U.S. patent application number 14/933137 was filed with the patent office on 2016-02-25 for light source unit, optical conversion unit, light source apparatus and light source system for an endoscope.
This patent application is currently assigned to OLYMPUS CORPORATION. The applicant listed for this patent is OLYMPUS CORPORATION. Invention is credited to Takeshi Ito, Iwao Komazaki, Masahiro Nishio, Eiji Yamamoto.
Application Number | 20160054558 14/933137 |
Document ID | / |
Family ID | 46931334 |
Filed Date | 2016-02-25 |
United States Patent
Application |
20160054558 |
Kind Code |
A1 |
Ito; Takeshi ; et
al. |
February 25, 2016 |
Light Source Unit, Optical Conversion Unit, Light Source Apparatus
and Light Source System for an Endoscope
Abstract
A light source unit for use with an endoscope. The light source
including: a primary light source configured to emit primary light;
and a first connector provided on an optical path of the primary
light and to which each of a plurality of optical conversion units
are attachable and removable. Wherein each of the plurality of the
optical conversion units include an optical conversion element
having an optical conversion function to convert optical properties
of the primary light to generate secondary light and each of the
plurality of the optical conversion units further having a second
connector configured to detachably engage the first connector to
transmit the primary light to the optical conversion element; and
an optical conversion unit is selected from the plurality of
optical conversion units based on the optical conversion function
desired for the secondary light, the secondary light being an
illumination light of the endoscope.
Inventors: |
Ito; Takeshi; (Hino-shi,
JP) ; Yamamoto; Eiji; (Musashimurayama-shi, JP)
; Nishio; Masahiro; (Hachioji-shi, JP) ; Komazaki;
Iwao; (Saitama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OLYMPUS CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
OLYMPUS CORPORATION
Tokyo
JP
|
Family ID: |
46931334 |
Appl. No.: |
14/933137 |
Filed: |
November 5, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14038251 |
Sep 26, 2013 |
9228725 |
|
|
14933137 |
|
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|
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PCT/JP2012/058333 |
Mar 29, 2012 |
|
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14038251 |
|
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Current U.S.
Class: |
362/553 ;
362/558; 362/583 |
Current CPC
Class: |
H01S 5/02284 20130101;
F21Y 2115/30 20160801; H01S 5/0092 20130101; A61B 1/07 20130101;
G02B 6/0006 20130101; H01S 5/4025 20130101; G02B 6/0008 20130101;
F21V 29/85 20150115; F21V 17/002 20130101; G02B 23/2423 20130101;
G02B 23/2469 20130101; A61B 1/0653 20130101; G01N 21/8806 20130101;
G02B 23/2476 20130101; A61B 1/0638 20130101; F21Y 2101/00 20130101;
A61B 1/00126 20130101 |
International
Class: |
G02B 23/24 20060101
G02B023/24; F21V 8/00 20060101 F21V008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2011 |
JP |
2011-075282 |
Mar 30, 2011 |
JP |
2011-076078 |
Claims
1. A light source unit for use with an endoscope, the light source
unit comprising: a primary light source configured to emit primary
light; and a first connector provided on an optical path of the
primary light and to which each of a plurality of optical
conversion units are attachable and removable, wherein each of the
plurality of the optical conversion units include an optical
conversion element having an optical conversion function to convert
optical properties of the primary light to generate secondary light
and each of the plurality of the optical conversion units further
having a second connector configured to detachably engage the first
connector to transmit the primary light to the optical conversion
element; and an optical conversion unit is selected from the
plurality of optical conversion units based on the optical
conversion function desired for the secondary light, the secondary
light being an illumination light of the endoscope.
2. A light source system comprising: the light source unit
according to claim 1; and an optical conversion unit selected from
the plurality of optical conversion units having the second
connector detachably engaged with the first connector, wherein the
optical conversion unit is mounted in the endoscope.
3. The light source system according to claim 2, wherein the
optical conversion unit is mounted in a distal end unit of the
endoscope.
4. The light source system according to claim 2, the optical
conversion unit is exchangeable among the plurality of optical
conversion units.
5. The light source system according to claim 2, wherein the
optical conversion unit is selected to meet a predetermined
observation criteria of the endoscope.
6. The light source system according to claim 1, wherein the
primary light source consists of a laser light source.
7. The light source system according to claim 2, wherein the
plurality of optical conversion units each providing a different
optical conversion function to optically convert the primary light
into secondary light with a different optical property.
8. The light source system according to claim 7, wherein the
optical conversion function includes one or more of a peak
wavelength, a spectral shape, and a radiation angle.
9. The light source system according to claim 7, wherein the
plurality of optical conversion units include an optical conversion
unit with functions to convert a radiation angle and to avoid
converting a peak wavelength and a spectral shape, the radiation
angle, the peak wavelength, and the spectral shape being included
in the optical properties of the primary light.
10. The light source system according to claim 9, wherein the
optical conversion element of the optical conversion unit is a
radiation angle conversion element, and the radiation angle
conversion element is one of a diffusion member configured to
broaden a radiation angle of the primary light and a lens
configured to one of focus and scatter the primary light.
11. The light source system according to claim 2, wherein the
plurality of optical conversion units having different input
limitations on optically convertible optical properties including a
wavelength, a spectrum, and a light intensity of the primary
light.
12. The light source system according to claim 11, wherein at least
one optical conversion element of the plurality of optical
conversion units is a wavelength conversion member configured to
convert the primary light into light with a peak wavelength and a
spectrum different from a peak wavelength and a spectrum of the
primary light, and at least some of the plurality of optical
conversion units comprising wavelength conversion members with
different absorption rates for the wavelength of the primary
light.
13. The light source system according to claim 11, wherein at least
some of the plurality of optical conversion units having different
thermal resistance properties for heat generated in a corresponding
optical conversion element during a process from incidence of the
primary light to emission of the secondary light.
14. The light source system according to claim 11, wherein at least
some of the plurality of optical conversion units exhibiting
different thermal radiation properties in radiating heat to an
exterior of an optical conversion unit exhibiting the different
thermal radiation properties, the heat being generated in the
optical conversion unit exhibiting the different thermal radiation
properties during a process from incidence of the primary light to
emission of the secondary light.
15. The light source system according to claim 11, wherein at least
some of the plurality of optical conversion units having one or
more of different secondary light output area sizes and different
secondary light output shapes.
16. The light source system according to claim 2, wherein the light
source unit comprises a plurality of light source units each
emitting a different primary light, and each of the plurality of
light source units include the first connector.
17. The light source system according to claim 16, wherein at least
some of the plurality of light source units emitting primary light
differing in at least one of a peak wavelength, a spectrum shape,
and a maximum optical output.
18. The light source system according to claim 2, further
comprising: light guides configured to optically connect the light
source unit to a selected one of the plurality of optical
conversion units, wherein the light guides comprise a first light
guide optically connected between the primary light source and the
first connector and a second light guide optically connected
between the second connector and a corresponding optical conversion
unit of the selected one of the plurality of optical conversion
units.
19. The light source unit according to claim 1, wherein the light
source unit further comprises a light guide configured to optically
connect the primary light source to the first connector.
20. The light source system according to claim 2, wherein each of
the plurality of optical conversion units further includes a light
guide optically connected to a corresponding optical conversion
element, and the first and second connectors are provided between
the primary light source and the light guide.
21. The light source system according to claim 18, wherein the
light guides are one of an optical fiber and a film light
guide.
22. An optical conversion unit for use with an endoscope, the
optical conversion unit comprising: an optical conversion element
configured to convert optical properties of primary light to
generate secondary light, the optical conversion element being
selected from a plurality of optical conversion elements wherein at
least some of the plurality of optical conversion elements having
different optical conversion functions and the secondary light is
an illumination light of the endoscope; and a connector provided on
an optical path of the primary light and which is attachable to and
removable from a light source unit with a primary light source
configured to emit the primary light, wherein the optical
conversion unit is mounted in the endoscope.
23. The light source system according to claim 22, wherein the
optical conversion unit is mounted in a distal end unit of the
endoscope.
24. The light source system according to claim 22, wherein the
optical conversion unit is exchangeable among the plurality of
optical conversion units.
25. The light source system according to claim 22, wherein the
optical conversion unit is selected to meet a predetermined
observation criteria of the endoscope.
26. The light source system according to claim 22, wherein the
primary light source consists of a laser light source.
27. A light source apparatus for use with an endoscope, the light
source apparatus comprising: a light source unit with a primary
light source configured to emit primary light; an optical
conversion unit holder for holding a plurality of optical
conversion units, each having an optical conversion element
configured to convert optical properties of the primary light to
generate secondary light, the optical conversion unit holder being
selected from a plurality of optical conversion unit holders based
on an optical conversion function desired for the secondary light,
the secondary light being an illumination light of the endoscope; a
plurality of light guides configured to optically connect the
primary light source to the plurality of optical conversion units
by respective light guides; and for optically connecting the
primary light source to the plurality of optical conversion
units.
28. The light source apparatus according to claim 27, wherein the
connector comprises a first connector having first connection
portions attached to a light source unit side and a second
connector having second connector portions attached to an optical
conversion unit side, the first connector portions are integrated
together to form a first integrated connection portion, the second
connector portions are attached to a connection portion holding
member to form a second integrated connection portion, and the
first connector and the second connector form a removable
integrated connection portion.
29. The light source apparatus according to claim 28, wherein a
number of effective first connection portions in the first
connector is a number of first connection portions optically
connected to the primary light source, and a number of effective
second connection portions in the second connector is a number of
second connection portions attached to the connection portion
holding member of the second connector, and the number of effective
first connection portions in the first connector is greater than or
equal to the number of second effective connection portions in the
second connector.
30. The light source apparatus according to claim 29, wherein the
connection portion holding member includes connection portion
attachment positions to which the second connection portions are
attachable, and a light blocking member configured to prevent the
primary light from leaking to an exterior is provided at each of
connection portion attachment positions to which the second
connector portions are not attached.
31. The light source apparatus according to claim 28, wherein a
number of primary light sources in the light source unit is less
than or equal to the number of the first connection portions.
32. The light source apparatus according to claim 28, wherein each
of the plurality of optical conversion units comprises an optical
conversion function for at least one of a peak wavelength, a
spectral shape, and a radiation angle included in the optical
properties of the primary light, and the optical conversion unit
holder includes a plurality of optical conversion units with the
wavelength conversion functions which are different from one
another.
33. A light source system for use with an endoscope, the light
source system comprising: the light source apparatus according to
claim 28, and wherein the optical conversion unit holder forms an
integrated optical conversion unit group together with a plurality
of integrated optical conversion units different from the optical
conversion unit holder, and the integrated optical conversion units
which are members of the integrated optical conversion unit group
are all attachable to and removable from the light source unit at
the removable integrated connection portion.
34. The light source system according to claim 33, wherein the
integrated optical conversion unit group includes a plurality of
integrated optical conversion units each with the plurality of
optical conversion units attached on the optical conversion unit
holder at different positions.
35. The light source system according to claim 33, wherein the
integrated optical conversion unit group comprises an integrated
optical conversion unit including optical conversion units, each of
the optical conversion units having a different optical conversion
function for at least one of a peak wavelength, a spectral shape,
and a radiation angle included in the optical properties of the
primary light.
36. The light source system according to claim 33, wherein the
integrated optical conversion unit group includes at least one
integrated optical conversion unit with optical conversion units
and at least one integrated optical conversion unit with optical
conversion units which are different from, in number, the optical
conversion units of the integrated optical conversion unit.
37. A light source system using the light source apparatus
according to claim 28, wherein the light source unit forms a light
source unit group together with a plurality of light source units
different from the light source unit, the light source unit is used
for a primary light of the endoscope, and members of the light
source unit group are all attachable to and removable from members
of the plurality of optical conversion units at the removable
integrated connection portion
38. The light source system according to claim 37, wherein the
light source unit group comprises members which are able to radiate
primary light among which at least one of a peak wavelength, a
spectral shape, and a maximum output varies, the peak wavelength,
the spectral shape, and the maximum output being included in
optical properties of the primary light emitted by the light source
unit.
39. The light source system according to claim 37, wherein the
light source unit group comprises members among which a number of
primary light sources in the light source unit varies.
40. The light source system according to claim 37, wherein the
light source unit group comprises members among which a number of
the first connection portions in the first integrated connection
portion varies.
41. The light source apparatus according to claim 28, wherein at
least one of the plurality of light guides is one of an optical
fiber and a film light guide.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. application Ser. No.
14/038,251, filed on Sep. 26, 2013, which is a Continuation
Application of PCT Application No. PCT/JP2012/058333, filed Mar.
29, 2012, which was published under PCT Article 21(2) in Japanese,
and which is based upon and claims the benefit of priority from
prior Japanese Patent Application Nos. 2011-075282 and 2011-076078,
both filed Mar. 30, 2011, the entire contents of all of which
(i.e., U.S. application Ser. No. 14/038,251; PCT Application No.
PCT/JP2012/058333; and Japanese Patent Application Nos. 2011-075282
and 2011-076078) are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a light source unit, an
optical conversion unit, a light source apparatus, and a light
source system.
[0004] 2. Description of the Related Art
[0005] U.S. Patent Application No. 2006/0152926 proposes a light
emitting apparatus with a combination of a first unit with a second
unit. In this case, the first unit uses a blue laser light source
and a light guide to guides laser light emitted by the blue laser
light source and also uses a wavelength conversion member provided
at a distal end of the light guide to convert the wavelength of the
laser light. The second unit uses a laser light source for a
wavelength shorter than the wavelength of blue light, a light
guide, and a wavelength conversion member. U.S. Patent Application
No. 2006/0152926 discloses that the combination of the first unit
with the second unit improves a color rendering index compared to
the first unit alone.
[0006] In recent years, for observation light source apparatuses
such as endoscopes, much effort have been made to improve the
visibility of an observation target by appropriately selecting a
brightness level, a peak wavelength, a luminescent color, that is,
a spectral shape, a radiation angle, and the like according to the
purpose of the observation.
[0007] In connection with such effort, to obtain light that meets
the purpose, the light source apparatus in U.S. Patent Application
No. 2006/0152926 needs preparation of units each using a laser
light source, a light guide, and a wavelength conversion member and
the number of which is equal to the number of types of light needed
for the purpose. However, preparing a large number of units is
difficult in a practical sense in terms of costs, a storage site,
and the like.
BRIEF SUMMARY OF THE INVENTION
[0008] With the foregoing in view, it is an object of the present
invention to enable various types of light to be radiated according
to the purpose.
[0009] According to a first aspect of the invention, there is
provided a light source unit comprising: a primary light source
configured to emit primary light; and a connection portion provided
on an optical path of the primary light and to and from which an
optical conversion unit is attachable and removable, the optical
conversion unit including an optical conversion element configured
to convert optical properties of the primary light to generate
secondary light.
[0010] According to a second aspect of the invention, there is
provided a light source system comprising: the light source unit
according to the first aspect of the invention; and an optical
conversion unit group comprising a plurality of optical conversion
units, and wherein the optical conversion units belonging to the
optical conversion unit group are connectible to the light source
unit by the connection portion.
[0011] According to a third aspect of the invention, there is
provided an optical conversion unit comprising: an optical
conversion element configured to convert optical properties of
primary light to generate secondary light; and a connection portion
provided on an optical path of the primary light and which is
attachable to and removable from a light source unit with a primary
light source configured to emit the primary light.
[0012] According to a fourth aspect of the invention, there is
provided a light source apparatus comprising: a light source unit
with a primary light source configured to emit primary light; a
plurality of optical conversion units each having an optical
conversion element configured to convert optical properties of the
primary light to generate secondary light; a plurality of light
guides configured to optically connect the primary light source to
the plurality of optical conversion units by respective light
guides; and a connection portion provided on each of the light
guides, the primary light source and a corresponding one of the
plurality of optical conversion units being attachable to and
removable from the connection portion.
[0013] According to a fifth aspect of the invention, there is
provided a light source system comprising a light source apparatus
comprising: a light source unit with a primary light source
configured to emit primary light; a plurality of optical conversion
units each having an optical conversion element configured to
convert optical properties of the primary light to generate
secondary light; a plurality of light guides configured to
optically connect the primary light source to the plurality of
optical conversion units by respective light guides; and a
connection portion provided on each of the light guides, the
primary light source and a corresponding one of the plurality of
optical conversion units being attachable to and removable from the
connection portion, the plurality of optical conversion units being
attached to a common optical conversion unit holding member to form
an integrated optical conversion unit, first connection portions
being integrated together to form a first integrated connection
portion when the first connection portions included in the
connection portion are attached to a light source unit side and
second connection portions included in the connection portion are
attached to an optical conversion unit side, the second connection
portions being attached to one connection portion holding member to
form a second integrated connection portion, the first integrated
connection portion and the second integrated connection portion
forming the removable integrated connection portion, wherein the
integrated optical conversion unit forms an integrated optical
conversion unit group together with a plurality of integrated
optical conversion units different from the integrated optical
conversion unit, and the integrated optical conversion units which
are members of the integrated optical conversion unit group are all
attachable to and removable from the light source unit at the
integrated connection portion.
[0014] According to a sixth aspect of the invention, there is
provided a light source system using a light source apparatus
comprising: a light source unit with a primary light source
configured to emit primary light; a plurality of optical conversion
units each having an optical conversion element configured to
convert optical properties of the primary light to generate
secondary light; a plurality of light guides configured to
optically connect the primary light source to the plurality of
optical conversion units by respective light guides; and a
connection portion provided on each of the light guides, the
primary light source and a corresponding one of the plurality of
optical conversion units being attachable to and removable from the
connection portion, the plurality of optical conversion units being
attached to a common optical conversion unit holding member to form
an integrated optical conversion unit, first connection portions
being integrated together to form a first integrated connection
portion when the first connection portions included in the
connection portion are attached to a light source unit side and
second connection portions included in the connection portion are
attached to an optical conversion unit side, the second connection
portions being attached to one connection portion holding member to
form a second integrated connection portion, the first integrated
connection portion and the second integrated connection portion
forming the removable integrated connection portion, wherein the
light source unit forms a light source unit group together with a
plurality of light source unit different from the light source
unit, and members of the light source unit group are all attachable
to and removable from members of the integrated optical conversion
unit group at the integrated connection portion.
[0015] According to the present invention, because various light
source units can be connected to various optical conversion units
or by replacing the integrated optical conversion unit according to
the purpose because the integrated optical conversion unit can be
replaced for one light source unit. Therefore, any of various types
of light meeting the purpose can be radiated by using a combination
of the light source unit with the optical conversion unit which
allows target light to be radiated.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0016] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate embodiments of
the invention, and together with the general description given
above and the detailed description of the embodiments given below,
serve to explain the principles of the invention.
[0017] FIG. 1 is diagram showing a configuration of a light source
system according to a first embodiment of the present
invention;
[0018] FIG. 2A is a cross-sectional view showing a configuration of
a first optical conversion unit;
[0019] FIG. 2B is a cross-sectional view showing a configuration of
a second optical conversion unit;
[0020] FIG. 2C is a cross-sectional view showing a configuration of
a third optical conversion unit;
[0021] FIG. 3A is a diagram illustrating optical conversion
characteristics of the first optical conversion unit, wherein the
axis of ordinate represents light intensity and the axis of
abscissas represents wavelength;
[0022] FIG. 3B is a diagram illustrating optical conversion
characteristics of the first optical conversion unit, wherein the
axis of ordinate represents light intensity and the axis of
abscissas represents wavelength;
[0023] FIG. 4 is a diagram illustrating a spectrum of light emitted
when the first light source unit and the first optical conversion
unit are combined together;
[0024] FIG. 5A is a diagram illustrating optical conversion
characteristics of the second optical conversion unit, wherein the
axis of ordinate represents light intensity and the axis of
abscissas represents wavelength;
[0025] FIG. 5B is a diagram illustrating optical conversion
characteristics of the second optical conversion unit, wherein the
axis of ordinate represents light intensity and the axis of
abscissas represents wavelength;
[0026] FIG. 6 is a diagram illustrating optical conversion
characteristics of the third optical conversion unit;
[0027] FIG. 7 is diagram showing a configuration of a light source
system according to a second embodiment of the present
invention;
[0028] FIG. 8A is a cross-sectional view showing a configuration of
a fourth optical conversion unit;
[0029] FIG. 8B is a cross-sectional view showing a configuration of
a fifth optical conversion unit;
[0030] FIG. 9A is a diagram showing a configuration of a first
optical conversion unit in a light source system according to a
third embodiment of the present invention;
[0031] FIG. 9B is a cross-sectional view showing a configuration of
a sixth optical conversion unit;
[0032] FIG. 9C is a cross-sectional view showing a configuration of
a seventh optical conversion unit;
[0033] FIG. 10 is diagram showing a configuration of a light source
system according to a fourth embodiment of the present
invention;
[0034] FIG. 11A is a cross-sectional view showing a configuration
of an eight optical conversion unit;
[0035] FIG. 11B is a cross-sectional view showing a configuration
of a ninth optical conversion unit;
[0036] FIG. 11C is a cross-sectional view showing a configuration
of a tenth optical conversion unit;
[0037] FIG. 12 is a diagram showing a configuration of a light
source system according to a modification of a fourth
embodiment;
[0038] FIG. 13 is diagram showing a configuration of a light source
system according to a fifth embodiment of the present
invention;
[0039] FIG. 14 is a diagram illustrating a modification of the
first to fifth embodiments of the present invention;
[0040] FIG. 15 is a diagram illustrating a configuration of a film
light guide;
[0041] FIG. 16 is diagram showing a configuration of a light source
system according to a sixth embodiment of the present
invention;
[0042] FIG. 17A is a cross-sectional view showing a configuration
of a first integrated optical conversion unit;
[0043] FIG. 17B is a cross-sectional view showing a configuration
of a second integrated optical conversion unit;
[0044] FIG. 17C is a cross-sectional view showing a configuration
of a third integrated optical conversion unit;
[0045] FIG. 18 is a perspective view showing a configuration of an
integrated connection portion;
[0046] FIG. 19 is diagram showing a configuration of a light source
system according to a seventh embodiment of the present
invention;
[0047] FIG. 20A is a diagram showing a configuration of a fourth
integrated optical conversion unit;
[0048] FIG. 20B is a diagram showing another example of
configuration of the fourth integrated optical conversion unit;
[0049] FIG. 21 is a diagram illustrating the operation of a
combination of an eleventh light source unit with the fourth
integrated optical conversion unit;
[0050] FIG. 22 is a diagram showing a twelfth light source
unit;
[0051] FIG. 23 is a diagram showing a thirteenth light source
unit;
[0052] FIG. 24 is a diagram showing a fourteenth light source unit;
and
[0053] FIG. 25 is a diagram illustrating an optical coupler
according to a modification of the sixth and seventh
embodiments.
DETAILED DESCRIPTION OF THE INVENTION
[0054] Embodiments of the present invention will be described below
with reference to the drawings.
First Embodiment
[0055] First, a configuration of a light source system according to
a first embodiment of the present invention will be described.
[0056] As shown in FIG. 1, the light source system according to the
present embodiment includes a light source unit group including a
plurality of light source units 10-1 and 10-2 and an optical
conversion unit group including a plurality of optical conversion
units 12-1, 12-2, and 12-3. A light source apparatus can be
configured by combining one light source unit 10-1 or 10-2 with one
optical conversion unit 12-1, 12-2, or 12-3.
[0057] According to the present embodiment, each of the light
source units 10-1 and 10-2 includes a connector 14 with a structure
common to all of the light source units. Furthermore, all of the
optical conversion units 12-1, 12-2, and 12-3 include a connector
16 that can be attached to and removed from the connector 14. Thus,
all the members of the light source unit group can be connected to
all the members of the optical conversion unit group in all
combinations.
[0058] The light source system according to the present embodiment
can deliver different types of illumination light simply by
replacing the optical conversion unit 12-1, 12-2, or 12-3 for the
light source unit 10-1 or 10-2.
[0059] As shown in FIG. 1, each of the light source units 10-1 and
10-2 includes a semiconductor laser 18-1 or 18-2, respectively, an
optical fiber 20, and a connector 14. In this case, the
semiconductor lasers 18-1 and 18-2 are primary light sources that
emit primary light. The optical fiber 20 functions as a first light
guide. The connector 14 is one of two connectors forming a
connection portion 22 which is provided on an optical path for
primary light traveling through the optical fiber 20 and to and
from which any of the optical conversion units 12-1, 12-2, and 12-3
can be attached and removed.
[0060] The semiconductor laser 18-1 mounted on the first light
source unit 10-1 is, for example, a blue semiconductor laser that
emits blue light with a wavelength of about 450 nm. The
semiconductor laser 18-1 and the optical fiber 20 are optically
connected together by a lens (not shown in the drawings) or the
like and configured such that blue laser light that is primary
light emitted by the semiconductor laser 18-1 efficiently enters a
core of the optical fiber 20. The blue laser light having entered
the optical fiber 20 is guided via the connection portion 22 to the
optical conversion unit 12-1, 12-2, or 12-3 connected to the
connection portion 22.
[0061] Furthermore, in the second light source unit 10-2, the
semiconductor laser 18-2 emits laser light with a wavelength
different from the wavelength of laser light emitted by the
semiconductor laser 18-1. The semiconductor laser 18-2 mounted on
the light source unit 10-2 is, for example, a blue-violet
semiconductor laser that emits blue-violet light with a wavelength
of about 405 nm.
[0062] As shown in FIG. 2A, the first optical conversion unit 12-1
includes a connector 16, an optical fiber 24, a phosphor 26-1, and
a holding member 28-1. The connector 16 is one of the two
connectors forming the connection portion 22 which is provided on
the optical path for the primary light, and can be attached to and
removed from the connector 14 of the light source unit 10-1 or
10-2. The optical fiber 24 is a second light guide configured to
guide the primary light from the connector 16 to a wavelength
conversion member serving as an optical conversion element. The
wavelength conversion member is inserted into the cylinder of the
holding member 28-1, which is shaped like a bottomed cylinder. In
the first optical conversion unit 12-1 according to the present
embodiment, the wavelength conversion member is, for example, the
phosphor 26-1, which absorbs the primary light to convert the
primary light so as to shift to longer the peak wavelength thereof
and to broaden the spectral shape and radiation angle. The phosphor
26-1 is formed by mixing powdery fluorescent substance with resin,
glass, or the like, which has the property of allowing the primary
light to pass through, and solidifying the mixture. The holding
member 28-1 includes an opening formed in the bottom surface of the
cylinder and in which a ferrule 30 and the optical fiber 24
disposed in the ferrule 30 are interposed. According to the present
embodiment, the fluorescent substance in the phosphor 26-1 is
formed of Ce-doped yttrium aluminum garnet (YAG) phosphor mixed
into a transparent silicone resin. The phosphor 26-1 is a shaped
like a cylinder with a thickness adjusted such that optical
characteristics of secondary light emitted by the phosphor 26-1 are
optimum for observation light.
[0063] As shown in FIG. 2B, the second optical conversion unit 12-2
is basically configured similarly to the first optical conversion
unit 12-1. The second optical conversion unit 12-2 is different
from the first optical conversion unit 12-1 in a holding member
28-2 and an optical conversion element interposed in the holding
member 28-2. The optical conversion unit 12-2 includes a radiation
angle conversion element interposed therein as an optical
conversion element. Specifically, the radiation angle conversion
element is a diffusion member 32 that diffuses the primary light.
The diffusion member 32 has a function to broaden the radiation
angle of the primary light without converting the peak wavelength
or spectral shape thereof. The diffusion member is formed by
mixing, into a first member having the property of allowing the
primary light to pass through, a second member with a refractive
index different from the refractive index of the first member, and
solidifying the mixture. For example, the diffusion member is
formed by mixing a resin with a refractive index of 1.4 and a glass
filler with a refractive index of 1.5. The diffusion member 32 has
a thickness adjusted such that the optical characteristics of
secondary light emitted by the diffusion member 32 are optimum for
observation light.
[0064] As shown in FIG. 2C, the third optical conversion unit 12-3
is basically configured similarly to the first optical conversion
unit 12-1. The third optical conversion unit 12-3 is different from
the first optical conversion unit 12-1 in a holding member 28-3 and
an optical conversion element interposed in the holding member
28-3. The optical conversion element in the optical conversion unit
12-3 includes a collimate lens group 34 arranged in predetermined
positional relationships to convert primary light into collimate
light and to emit the collimate light as secondary light. The
collimate lens group is set such that the emitted secondary light
has an optimum beam diameter for observation light.
[0065] The material for the holding members 28-1, 28-2, and 28-3 is
illustrated as resin in FIGS. 2A to 2C but is not particularly
specified. Any material such as metal, resin, or ceramic may be
used provided that the material enables the optical conversion
element to be held.
[0066] Each of the optical fibers 20 and 24 is a common single
optical fiber configured such that the core has a higher refractive
index than a clad. The type of optical fiber is selected according
to characteristics of a primary light source used in combination
with the optical fiber. According to the present embodiment, the
multimode semiconductor lasers 18-1 and 18-2 are used as a primary
light source, and thus, the suitable type is a multimode fiber.
Furthermore, the suitable optical fibers 20 and 24 have the same
optical characteristics. This enables a reduction in loss on the
connection portion 22. For example, a step index optical fiber may
be used which has a core diameter of about 50 .mu.m and a numerical
aperture NA of about 0.22.
[0067] The connection portion 22 may be connectors that very
efficiently connect the optical fibers 20 and 24 together. Although
not shown in the drawings, the connection portion has a function to
align ferrules with each other via sleeves or the like for
fixation. Common optical connectors may be used.
[0068] Now, the operation of the light source system according to
the present embodiment will be described.
[0069] As described above, the light source system according to the
present embodiment is configured such that the two light source
units 10-1 and 10-2, the members of the light source unit group,
can be connected, by the connection portion 22, to the three
optical conversion units 12-1, 12-2, and 12-3, the members of the
optical conversion unit group, in all combinations.
[0070] First, an operation will be described which is performed by
a combination of the first light source unit 10-1 with any of the
three optical conversion units 12-1, 12-2, and 12-3.
[0071] First, an operation will be described which is performed by
a light source apparatus with a combination of the first light
source unit 10-1 with the optical conversion unit 12-1.
[0072] The semiconductor laser 18-1 of the first light source unit
10-1 is connected to a power source and a control circuit that
provide predetermined power to the first light source unit 10-1.
The semiconductor laser 18-1 thus emits laser light with a
wavelength of 450 nm. Blue laser light emitted by the semiconductor
laser 18-1 is focused on a proximal end of the optical fiber 20 by
a lens or the like (not shown in the drawings). The blue laser
light enters the core of the optical fiber 20 and is guided through
the optical fiber 20 and emitted from the connector 14 toward the
connector 16 in the connection portion 22. The blue laser light
delivered to the connector 16 enters the core of the optical fiber
24 and is guided through the optical fiber 24 and delivered to the
phosphor 26-1, which is an optical conversion member interposed in
the holding member 28-1 of the first optical conversion unit
12-1.
[0073] The blue laser light having entered the phosphor 26-1 is
partly absorbed by the Ce-doped YAG, a fluorescent substance
distributed in the phosphor 26-1. The blue laser light thus has the
wavelength thereof converted and becomes yellow fluorescence, which
is then radiated. That is, as shown in FIG. 3A, the phosphor 26-1
converts the peak wavelength from 450 to 550 nm, and for the
spectral shape, converts a spectrum with a line width (full width
at half maximum [FWHM]) of about 1 to 2 nm into a broad spectrum
with a line width of 50 nm or more. Furthermore, another portion of
the blue laser light having entered the phosphor 26-1 is scattered
in the phosphor 26-1 and radiated to the exterior. Additionally,
for the radiation angle, the Ce-doped YAG absorbs a portion of blue
laser light 36 and emits yellow fluorescence 38 in various
directions regardless of the direction in which the blue laser
light 36 enters the phosphor 26-1, as shown in FIG. 3B. Thus, the
yellow fluorescence 38 has a very wide radiation angle.
Transmission light 40 contained in the blue laser light and
scattered and radiated to the exterior instead of being absorbed by
the phosphor 26-1 has a wider radiation angle than the blue laser
light 36 as is not scattered. The transmission light 40 has a
radiation angle substantially equal to the radiation angle of the
yellow fluorescence 38.
[0074] That is, the first optical conversion unit 12-1 has a
function to convert all of the peak wavelength, the spectral shape,
and the radiation angle for a portion of the blue laser light and
to convert only the radiation angle and avoid converting the peak
wavelength and the spectral shape for the remaining portion of the
blue laser light.
[0075] As a result, a light source apparatus with a combination of
the first light source unit 10-1 with the first optical conversion
unit 12-1 radiates illumination light serving as secondary light
and having such a spectrum as shown in FIG. 4 and a radiation angle
corresponding to the transmission light 40 and yellow fluorescence
38 of the blue laser shown in FIG. 3B. The illumination light is
white light formed of blue light and yellow light that is a
complementary color for the blue light. Thus, this combination
enables provision of a light source apparatus that radiates white
light.
[0076] Now, the operation of a light source apparatus with a
combination of the first light source unit 10-1 with the second
optical conversion unit 12-2 will be described. The basic operation
of this light source apparatus is similar to the basic operation of
the light source apparatus with the combination of the first light
source unit 10-1 with the second optical conversion unit 12-1. Only
differences between these light source apparatuses will be
described.
[0077] Blue laser light emitted by the first light source unit 10-1
is delivered through the optical fiber 20, the connection portion
22, and the optical fiber 24 to the diffusion member 32 interposed
inside the holding member 28-2 of the second optical conversion
unit 12-2. The diffusion member 32 has a function to avoid
converting the peak wavelength and spectral shape of the blue laser
light and convert only the radiation angle of the blue laser light.
FIG. 5A and FIG. 5B show the spectrum and radiation angle of
illumination light radiated by the second optical conversion unit
12-2 configured as described above.
[0078] As shown in FIG. 5A, the spectrum has a wavelength of 450 nm
and a spectral line width of 1 to 2 nm, which are the same as the
wavelength and spectral line width of the laser light emitted by
the semiconductor laser 18-1. On the other hand, as shown in FIG.
5B, the original laser light is blue laser light 42 having a much
wider radiation angle than the laser light radiated from the
optical fiber 24 (36 in FIG. 5B).
[0079] As a result, the combination of the first light source unit
10-1 with the second optical conversion unit 12-2 provides
illumination light having the same wavelength and spectrum as those
of the laser light and a wider radiation angle than the laser
light. The illumination light with a wide radiation angle is also
characterized in that the laser light provides significantly
reduced coherence, thus making speckles and the like unlikely to
occur.
[0080] Now, the operation of a light source apparatus with a
combination of the first light source unit 10-1 with the third
optical conversion unit 12-3 will be described. The basic operation
of this light source apparatus is similar to the basic operations
in the above-described two examples of combinations. Here, only
differences will be described.
[0081] Blue laser light emitted by the first light source unit 10-1
is delivered through the optical fiber 20, the connection portion
22, and the optical fiber 24 to the collimate lens group 34
interposed in the holding member 28-3 of the third optical
conversion unit 12-3. The blue laser light having entered the
collimate lens group 34 is converted into collimate light beams 44
that are parallel light beams, and the collimate light beams 44 are
delivered to the exterior. This is shown in FIG. 6, which is an
image drawing. Without the collimate lens group, the blue laser
light 36 would be radiated so as to have a divergence angle (36 in
FIG. 6). In contrast, the collimate light beams 44 can be delivered
to an illumination target with the beam diameter approximately
unchanged. The third optical conversion unit 12-3 has a function to
convert the blue laser light into parallel light beams, that is,
has only a function to convert and narrow the radiation angle and
an optical conversion function to avoid converting the peak
wavelength and the spectral line width. As described above, the use
of the third optical conversion unit 12-3 allows a remote
illumination target to be illuminated with the beam diameter
approximately unchanged. As a result, light beams with a relatively
high power density can be delivered to the illumination target.
[0082] As described above, the combination of the first light
source unit 10-1 with any of the three optical conversion units
12-1, 12-2, and 12-3 enables the single light source unit 10-1 to
provide three different types of illumination light, that is, white
light, laser diffused light, and collimate light.
[0083] Now, an operation will be described which is performed by a
combination of the second light source unit 10-2, which emits
blue-violet laser light with a wavelength of 405 nm, with any of
the three optical conversion units 12-1, 12-2, and 12-3.
[0084] A basic operation in this case is similar to the basic
operation in the case where the first light source unit 10-1 is
used as described above. Thus, mainly differences will be
described. The operation of the combination of the second light
source unit 10-2 with either of the second and third optical
conversion unit 12-2 and 12-3 is approximately equal to the
operation of the combination of the first light source unit 10-1
with any of the optical conversion units and will thus not be
described. Only the combination of the first light source unit 10-2
with the optical conversion unit 12-1 will be described.
[0085] That is, blue-violet laser light emitted by the second light
source unit 10-2 is delivered through the optical fiber 20, the
connection portion 22, and the optical fiber 24 to the phosphor
26-1 interposed in the holding member 28-1 of the first optical
conversion unit 12-1. The Ce-doped YAG of the phosphor 26-1 absorbs
much of the blue light with a wavelength of 450 nm to perform a
wavelength conversion to convert the blue light into yellow
fluorescence, but absorbs little of the blue-violet light with a
wavelength of 405 nm, thus involving substantially none of such a
wavelength conversion as shown in FIG. 3A. That is, the phosphor
26-1 serving as an optical conversion element absorbs two types of
primary light at different absorption rates, and thus, absorbs much
of the primary light with a wavelength of 450 nm to convert the
primary light into white light but absorbs little of the primary
light with a wavelength of 405 nm to emit the primary light without
any change. However, the Ce-doped YAG, a fluorescent member
arranged in the phosphor 26-1 in a distributed manner, has a
refractive index of about 1.8, which is larger than the refractive
index of common glass or resin, which is used for sealing; the
common glass or resin or the like has a refractive index of about
1.4 to about 1.5. Thus, the phosphor 26-1 interposed in the first
optical conversion unit 12-1 acts on the blue-violet laser light in
a manner substantially equal to the manner in which the diffusion
member 32 acts on the blue-violet laser light. That is, as shown in
FIG. 5A and FIG. 5B, an optical conversion is carried out so as to
broaden only the radiation angle, with the peak wavelength and the
spectral shape substantially unconverted. In other words, for the
second light source unit 10-2, the first optical conversion unit
12-1 provides an optical conversion function similar to the optical
conversion function of the second optical conversion unit 12-2 with
the diffusion member 32.
[0086] That is, when white light and diffusion light of blue-violet
light are to be used for observation, the observation can be
achieved simply by preparing the two light source unit 10-1 and
10-2 and combining each of the light source unit 10-1 and 10-2 with
the first optical conversion unit 12-1.
[0087] As described above, various types of illumination light can
be obtained by appropriately combining the members of the light
source unit group with the members of the optical conversion unit
group.
[0088] As described above, according to the first embodiment, the
connection portion 22 is provided at a primary light output end of
each of the light source units 10-1 and 10-2 and configured such
that any of the various optical conversion units 12-1, 12-2, and
12-3 can be attached to and removed from the connection portion 22.
In the light source system according to the first embodiment, the
various light source units 10-1 and 10-2 and optical conversion
units 12-1, 12-2, and 12-3 are prepared and connected together by
the compatible connection portion 22, so that various combinations
can be made. Thus, various types of illumination light can be
provided by a reduced number of members.
[0089] Such a conventional configuration as disclosed in the U.S.
Patent Application No. 2006/0152926 needs units each with a
combination of a light source unit with an optical conversion unit
the number of which is equal to the number of types of illumination
light. In contrast, the first embodiment can provide a number of
types of illumination light the number of which is equal to the
number of light source units multiplied by the number of optical
conversion units. A large number of types of illumination light can
be very effectively produced using a small number of members.
[0090] Furthermore, if a space in which the optical conversion
units are mounted is limited as is the case with an endoscope or
the like, such a conventional configuration as disclosed in the
U.S. Patent Application No. 2006/0152926 limits the number of types
of illumination light that can emitted. In contrast, the
configuration according to the present embodiment provides various
types of illumination light by preparing a number of light source
units and a number of optical conversion units the numbers of which
correspond to the needed types of illumination light (for example,
the light source units 10-1 and 10-2 and the optical conversion
units 12-1, 12-2, and 12-3) and appropriately replacing the light
source units and the optical conversion units.
[0091] That is, a light source system can be provided which allows
a light source apparatus capable of radiating various types of
light to be arranged with high space efficiency by appropriately
selecting a combination of either of the light source units 10-1
and 10-2 with any of the optical conversion units 12-1, 12-2, and
12-3.
[0092] The configuration shown in FIG. 1 of the first embodiment is
only an example and only illustrates a simplified system with two
types of light source units (light source units 10-1 and 10-2) and
three types of optical conversion units (optical conversion units
12-1, 12-2, and 12-3) for simplification. For practical use, more
light source units and more optical conversion units may be
appropriately prepared according to the needed functions of the
illumination light. The primary light source mounted on the light
source unit is not limited to the semiconductor laser but may be
any of various light sources such as various laser light sources,
LEDs, and lamps. More desirably, the light source can be
efficiently connected to an optical fiber.
[0093] The optical conversion element mounted in the optical
conversion unit is also not limited to the above-described
phosphor, diffusion member, and collimate lens system but may be
any of various optical conversion elements. Examples of the usable
optical conversion element include not only various powdery
phosphors, ceramic phosphors, and single crystal phosphors, but
also a quantum dot, a semiconductor light emitting element, and an
organic light emitting element. Furthermore, the diffusion member
may be of a type including a transparent member the surface of
which is processed to include recesses and protrusions. Moreover,
when a directional optical conversion element such as a diffraction
grating, a polarizing element, or a photonic crystal is used, the
radiation angle or intensity distribution of emitted secondary
light can be made directional. In addition, the use of various
wavelength filters enables only the light in the desired wavelength
range to be extracted or cut.
[0094] Moreover, in the present embodiment, only the example in
which the single optical conversion element is used has been
described. However, the present embodiment is not limited to the
embodiment. A plurality of optical conversion elements can be
mounted in one holding member. For example, when a filter that cuts
a portion of the wavelength of fluorescence is disposed on an
output surface of the phosphor, exclusively the fluorescence in the
desired wavelength region can be extracted. Furthermore, mounting a
filter that cuts the primary light enables only the fluorescence to
be extracted.
Second Embodiment
[0095] Now, a second embodiment of the present invention will be
described.
[0096] The basic configuration of the second embodiment is the same
as the basic configuration of the first embodiment. Thus, only
differences from the first embodiment will be described.
[0097] A light source system according to the present embodiment is
configured as shown in FIG. 7 and basically configured similarly to
the light source system according to the first embodiment. The
second embodiment is different from the first embodiment in the
organization of the members of a light source unit group and the
organization of the members of an optical conversion unit
group.
[0098] That is, the light source unit group according to the
present embodiment includes two light source unit 10-1 and 10-3 as
members. The first light source unit 10-1 includes a semiconductor
laser 18-1 that emits 450-nm blue laser light. Furthermore, the
third light source unit 10-3 similarly includes a semiconductor
laser 18-3 that emits 450-nm blue laser light. The two
semiconductor lasers 18-1 and 18-3 are different from each other in
the maximum intensity of light that can be output, that is, the
maximum optical output. The semiconductor laser 18-1 is a blue
semiconductor laser with a maximum optical output of 100 mW. On the
other hand, the semiconductor laser 18-3 is a blue semiconductor
laser with a maximum optical output of 1,000 mW.
[0099] The remaining part of the configuration is similar to the
corresponding part of the configuration of the first
embodiment.
[0100] The optical conversion unit group according to the present
embodiment includes three optical conversion units 12-1, 12-4, and
12-5 as members. The first optical conversion unit 12-1 includes a
holding member 28-1 with a phosphor 26-1 interposed therein as is
the case with the first embodiment. Furthermore, the fourth optical
conversion unit 12-4 includes a holding member 28-4 with a phosphor
26-2 interposed therein and which is different from the phosphor
26-1. The fifth optical conversion unit 12-5 uses the phosphor 26-1
and includes a holding member 28-5 with a thermal radiation member
46 connected thereto.
[0101] Of the three optical conversion units, the two optical
conversion units 12-4 and 12-5 will be described, which are
different from the corresponding optical conversion units in the
first embodiment.
[0102] As shown in FIG. 8A, the fourth optical conversion unit 12-4
appears similar to the first optical conversion unit 12-1 shown in
FIG. 2A. The phosphor 26-1 in the first optical conversion unit
12-1 includes Ce-doped YAG solidified in a silicone resin in a
distributed manner. In contrast, a phosphor 26-2 in the fourth
optical conversion unit 12-4 includes a powder of Ce-doped YAG
which is a fluorescent substance and which is dispersed in glass in
order to improve thermal resistance. The Ce-doped YAG, which is a
fluorescent substance, offers sufficiently high thermal resistance,
whereas the silicone resin may be yellowed or subjected to cracks
or the like to exhibit degraded performance as an optical
conversion element when held at higher than about 200.degree. C.
for a long time. In comparison, the phosphor 26-2 using glass does
not substantially have its performance degraded even at high
temperatures greater than or equal to 400.degree. C.
[0103] The holding member 28-4 of the fourth optical conversion
unit 12-4 is shaped similarly to the holding member 28-1 of the
first optical conversion unit 12-1 but is formed of a highly
heat-resistant material. As described above, any holding member
28-1 may be used provided that the holding member 28-1 can hold the
phosphor 26-1. In contrast, the holding member 28-4 is a highly
heat-resistant material, for example, metal or ceramic.
[0104] In the above-described configuration, the fourth optical
conversion unit 12-4 can offer higher thermal resistance than the
first optical conversion unit 12-1.
[0105] As shown in FIG. 8B, the fifth optical conversion unit 12-5
includes a phosphor 26-1 mounted therein as an optical conversion
element positioned inside a holding member 28-5, the phosphor 26-1
being similar to the phosphor in the first optical conversion unit
12-1. The holding member 28-5 is formed of a highly thermally
conductive member. The highly thermally conductive member is, for
example, aluminum or copper. Furthermore, any highly thermally
conductive member other than metal may be used. The appropriate
thermal conductivity of the usable highly thermally conductive
member is 0.1 W/mK or higher. The appropriate thermal conductivity
is desirably 1.0 W/mK or higher.
[0106] A metal wire as a thermal radiation member 46 is connected
to the holding member 28-5. The metal wire is formed of copper or
the like, which has high thermal conductivity, and is thermally
connected to the holding member 28-5. The thermal radiation member
46 may also be any highly thermally conductive member other than
the metal wire, for example, a metallic rod or mesh or carbon
fiber. The appropriate thermal conductivity of the usable thermal
radiation member 46 is 0.1 W/mK or higher. The appropriate thermal
conductivity is desirably 1.0 W/mK or higher.
[0107] Now, the operation of the light source system according to
the second embodiment will be described. The operation of the light
source system according to the second embodiment is basically the
same as the operation of the light source system according to the
first embodiment. Here, only differences from the first embodiment
will be described.
[0108] For light source apparatuses with all possible combinations
of the light source units 10-1 and 10-3 and the optical conversion
units 12-1, 12-4, and 12-5, a series of operations of turning blue
laser light radiated by the light source unit 10-1 or 10-3 into
white illumination light are similar to corresponding operations
according to the first embodiment.
[0109] First, the operation of a light source apparatus with a
combination of the first light source unit 10-1 with the fourth
optical conversion unit 12-4 will be described. The fourth optical
conversion unit 12-4 uses a highly heat-resistant phosphor 26-2 and
a highly heat-resistant holding member 28-4. Thus, the fourth
optical conversion unit 12-4 can be used at high temperatures
greater than or equal to 100.degree. C., at which the first optical
conversion unit 12-1 may suffer functional deterioration as a
result of degradation of the member. For example, even when
inserted into an engine for use immediately after the engine stops,
the fourth optical conversion unit 12-4 does not substantially
suffer functional deterioration as a result of degradation of the
member.
[0110] Now, the operation of a light source apparatus with a
combination of the first light source unit 10-1 with the fifth
optical conversion unit 12-5 will be described. The fifth optical
conversion unit 12-5 is configured to easily radiate heat resulting
from optical conversion by the phosphor 26-1 to the exterior of the
optical conversion unit 12-5 using the holding member 28-5 and the
thermal radiation member 46. Thus, the fifth optical conversion
unit 12-5 can be maintained at a lower surface temperature than the
first optical conversion unit 12-1, including no thermal radiation
member. For example, when the optical conversion unit may come into
contact with a living organism during use, this light source
apparatus may reduce the risk of thermal destruction of the living
tissue. Even for an endoscope or the like, which is used for the
human body, the light source unit apparatus can reduce the risk of
a burn or the like.
[0111] Now, the operation of a light source apparatus with a
combination of the third light source unit 10-3 with any of the
optical conversion units 12-1, 12-4, and 12-5 will be described.
The third light source unit 10-3 includes a blue semiconductor
laser 18-3 with a maximum optical output of 1,000 mW, which is 10
times as much as the maximum optical output of the blue
semiconductor laser 18-1 mounted on the first light source unit
10-1, which is 100 mW. Heat generated during a process in which a
phosphor absorbs blue laser light to emit yellow fluorescence is
generally proportional, in amount, to the intensity of incident
light. Thus, heat generated by the phosphor 26-1 when the third
light source unit 10-3 emits light at the maximum output is about
10 times as much as heat generated by the phosphor 26-1 when the
first light source unit 10-1 emits light at the maximum output.
[0112] First, the operation of a light source apparatus with a
combination of the third light source unit 10-3 with the first
optical conversion unit 12-1 will be described. Since the third
light source unit 10-3 has a higher maximum optical output than the
first light source unit 10-1, the third light source unit 10-3 can
increase brightness up to the limit of the first optical conversion
unit 12-1. That is, the third light source unit 10-3 allows bright
illumination light to be obtained until the local temperature of
the first optical conversion unit 12-1 reaches the thermal
resistance temperature limit of the silicone resin as a result of
heat generation involved in optical conversion. However, when, for
example, silicone with a thermal resistance temperature limit of
200.degree. C. is used as the phosphor 26-1, if even a part of the
silicone resin exceeds the thermal resistance temperature limit,
the resin in the phosphor 26-1 may be yellowed or cracked. Thus,
the brightness of the light source unit can no longer be
increased.
[0113] In such a case, the use of the fourth optical conversion
unit 12-4 with improved thermal resistance enables a further
increase in brightness. The fourth optical conversion unit 12-4 is
formed of a more thermally-resistant member than the first optical
conversion unit 12-1. Thus, the combination of the fourth optical
conversion unit 12-4 with the third light source unit 10-3 provides
brighter illumination light than the combination of the first
optical conversion unit 12-1 with the third light source unit 10-3.
Compared to the phosphor 26-1, the phosphor 26-2, including
Ce-doped YAG dispersed in glass, serves to significantly improve
thermal resistance. For example, the phosphor 26-2 has a low
possibility of being degraded even when 1,000-mW primary light
enters the phosphor 26-2. Furthermore, at an elevated atmospheric
temperature, the phosphor has a consistently increased local
temperature and is likely to be degraded even by an intensity of
primary light that does not affect the phosphor at room
temperature. However, the combination of the fourth optical
conversion unit 12-4 with the third light source unit 10-3 can be
used even for observation in an environment at elevated
temperatures.
[0114] Now, the operation of a light source apparatus with a
combination of the third light source unit 10-3 with the fifth
optical conversion unit 12-5 will be described. The fifth optical
conversion unit 12-5 is configured to efficiently release heat
generated by the phosphor 26-1 to the exterior. Thus, the fifth
optical conversion unit 12-5 not only enables a reduction in the
risk of affecting the living organism as described in connection
with the combination of the first light source unit 10-1 with the
first optical conversion unit 12-1, but also allows local heat
generation by the phosphor 26-1 to be reduced by thermal radiation.
As a result, even the use of the phosphor 26-1 with the same
thermal resistance enables brighter light emission.
[0115] As described above, the light source system according to the
second embodiment can mitigate degradation of the phosphor 26-1 or
26-2 and reduce an increase in the local temperature the phosphor
26-1 or 26-2 by using the optical conversion units 12-1, 12-4, and
12-5 with different thermal resistance properties and different
thermal radiation properties.
[0116] That is, when the optical conversion units 12-4 and 12-5 are
prepared which have improved thermal resistance and radiation
compared to the optical conversion unit 12-1, brighter illumination
light can be obtained, observation at elevated temperatures can be
achieved, and the risk of affecting the living organism can be
reduced. Furthermore, if the thermal resistance or radiation is
unwanted, implementation of the corresponding function may be
avoided to provide a simpler and less expensive optical conversion
unit 12-1.
[0117] The above-described configuration is only an example, and
for example, an optical conversion unit with a combination of the
highly thermally resistant phosphor 26-2 with the thermal radiation
member 46 can be produced. Thus, a light source apparatus allowing
the use of elevated temperatures and excitation light with high
intensity can be maintained at a low surface temperature.
[0118] Furthermore, the example in which the phosphors 26-1 and
26-2 provide white light has been illustrated. However, the present
embodiment is not limited to the example. Even when a diffusion
member 32 is used to convert the radiation angle, the diffusion
member may be formed using a highly thermally resistant member as a
base material or the thermal radiation member 46 may be provided.
Thus, the diffusion member allows the use of elevated temperatures
and high intensity light, and heat generation by the diffusion
member in connection with optical diffusion can be reduced. This
also applies to the use of an optical conversion element such as a
filter which generates heat in connection with optical
conversion.
Third Embodiment
[0119] Now, a third embodiment of the present invention will be
described.
[0120] The basic configuration of the third embodiment is the same
as the basic configuration of the first embodiment. Here, only
differences from the first embodiment will be described.
[0121] The light source system according to the third embodiment is
basically configured similarly to the light source system according
to the first embodiment. The third embodiment is different from the
first embodiment in the organization of the members of an optical
conversion unit group, and a light source unit group according to
the third embodiment is different from the light source unit group
according to the first embodiment in that the light source unit
group according to the third embodiment has only the first light
source unit 10-1 as a member.
[0122] Third embodiment has the same optical conversion function as
that of the first and second embodiments but is different from the
first and second embodiments in the shape and size of a holding
member provided at a distal end of an optical conversion unit.
[0123] That is, the optical conversion unit group according to the
third embodiment includes three optical conversion units 12-1,
12-6, and 12-7 as members as shown in FIG. 9A to FIG. 9C. In FIG.
9A to FIG. 9C, a figure shown on the left side is a cross-sectional
view showing the central axis of an optical fiber 24, and a figure
shown on the right is a front view of the optical conversion unit
as seen from a secondary light output side, that is, from the right
side of the figure shown on the left side. The basic structure of
each of the optical conversion units 12-1, 12-6, and 12-7 is
similar to that of the first optical conversion unit 12-1
illustrated in the first embodiment. However, the sixth and seventh
optical conversion units 12-6 and 12-7 are different from the first
optical conversion unit 12-1 only in the sizes and shapes of the
holding member and the phosphor.
[0124] The first optical conversion unit 12-1 shown in FIG. 9A is
the same as the first optical conversion unit 12-1 described in the
first embodiment and shown in FIG. 2A. FIG. 9B is a diagram showing
the sixth optical conversion unit 12-6 with the phosphor 26-1 and
holding member 28-1 of the first optical conversion unit 12-1
increased in radial size (a phosphor 26-3 and a holding member
28-6, respectively). The phosphor 26-3 has the same thickness as
that of the phosphor 26-1. FIG. 9C is a diagram showing the seventh
optical conversion unit 12-7. A phosphor 26-4 is one of two pieces
into which the phosphor 26-3 is cut, and a holding member 28-7 is
shaped to be suitable for holding the phosphor 26-4.
[0125] Now, the operation of the light source system according to
the third embodiment will be described. For all possible
combinations of the members belonging to the light source unit
group and the members belonging to the optical conversion unit
group, a series of operations of turning blue laser light into
white illumination light are similar to the operations of the
combination of the first light source unit 10-1 with the optical
conversion unit 12-1 according to the first embodiment.
[0126] Optical conversion units such as the first optical
conversion unit 12-1 which have small distal end diameters emit
light from small points and are thus similar to point light source.
The sixth optical conversion unit 12-6, which is large in size,
emits light more similarly to a surface light source than to a
point light source. Furthermore, light distribution and the like
vary depending on the shape.
[0127] As described above, the light source system according to the
third embodiment allows selection of any of the optical conversion
units 12-1, 12-6, and 12-7 which has the suitable size and shape
for limitations on the place where the optical conversion units are
mounted.
[0128] The third embodiment exerts the following effect in addition
to the effects illustrated in the first embodiment. That is, a
distal end unit can be selected so as to achieve the optimum space
efficiency for an area where an illumination apparatus is mounted
simply by appropriately selecting any of the optical conversion
units 12-1, 12-6, and 12-7 for the one light source unit 10-1. For
example, when the optical conversion unit is combined with an
imaging device or the like or needs to be mounted in a small space
such as in an endoscope, the suitable optical conversion unit can
be selected so as to effectively utilize the space in the gap
between the optical conversion unit and another member.
[0129] The shapes and sizes shown in FIG. 9A to FIG. 9C are only
examples, and the shape and size may be modified in various ways.
Optical conversion units can be produced which have different
shapes including an ellipse and a square and selected taking
mounting of an imaging device into account.
[0130] Furthermore, the optical conversion element is not limited
to the phosphor but any of various optical conversion elements may
be used such as an optical conversion element such as a diffusion
member or a collimate lens group which converts only the radiation
angle, a wavelength selection filter, and a combination
thereof.
Fourth Embodiment
[0131] Now, a fourth embodiment of the present invention will be
described.
[0132] The basic configuration of the fourth embodiment is the same
as the basic configuration of the first embodiment. Here, only
differences from the first embodiment will be described.
[0133] A light source system according to the fourth embodiment is
different from the light source systems according to the first to
third embodiments in the position of a connection portion to and
from which a light source unit and an optical conversion unit are
attached and removed.
[0134] That is, as shown in FIG. 10, the light source system
according to the present embodiment is different from the light
source system according to the first embodiment in that a
connection portion 48 is provided between a ferrule 30 and a
holding member rather than on an optical fiber 20 serving as a
light guide. A fourth light source unit 10-4 and a fifth light
source unit 10-5 and an eighth optical conversion unit 12-8, a
ninth optical conversion unit 12-9, and a tenth optical conversion
unit 12-10 are different from the first and second light source
units 10-1 and 10-2 and the first, second, and third optical
conversion units 12-1, 12-2, and 12-3 illustrated in the first
embodiment only in the position and structure of the connection
portion. The above-described units of the fourth embodiment have
the same optical functions as those of the above-described units of
the first embodiment corresponding to the units of the fourth
embodiment in the above-described order.
[0135] Each of the fourth and fifth light source units 10-4 and
10-5 includes a semiconductor laser 18-1 or 18-2, respectively, the
optical fiber 20, the ferrule 30, and a connector 50 of the
connection portion 48 as shown in FIG. 10. Although the connection
portion 48 is partly omitted from FIG. 10 for simplification, the
connector 50 and a connector 52 have a fitting structure such as a
joint which allows the connectors 50 and 52 to be fixed to each
other.
[0136] The connection portion 48 has a positioning function to
place the ferrule 30 in the optimum positional relationship with an
optical conversion element in a holding member 28-8, 28-9, or
28-10.
[0137] FIGS. 11A to 11C show cross-sectional views of the eighth,
ninth, and tenth optical conversion units 12-8, 12-9, and 12-10,
which are the members of the optical conversion unit group
according to the present embodiment.
[0138] A connector 52 of the connection portion 48 is formed on
each of optical conversion units 12-8, 12-9, and 12-10. Connector
52 is shaped like a ring and includes a through-hole formed therein
into which the ferrule 30 is fitted.
[0139] When the ferrule 30 disposed at the distal end of the
optical fiber from the fourth or fifth light source unit 10-4 or
10-5 is inserted through the through-hole in the connector 52 and
through a through-hole in the holding member 28-8, 28-9, or 28-10,
the connectors 50 and 52 are fitted and fixed together at a
position where an end of the ferrule 30 substantially contacts a
phosphor 26-1, a diffusion member 32, or a collimator lens group
34.
[0140] For all possible combinations of the members belonging to
the light source unit group and the members belonging to the
optical conversion unit group, the basic operation of the light
source system according to the fourth embodiment described above is
similar to the basic operation described in the first
embodiment.
[0141] As described above, the light source system according to the
fourth embodiment allows the structures of the optical conversion
units 12-8, 12-9, and 12-10 to be simplified without substantially
complicating the structure of the light source unit. Thus, the
light source system according to the fourth embodiment is suitable
for a reduction in size and costs.
[0142] Thus, the sizes and costs of the optical conversion units
12-8, 12-9, and 12-10 can be reduced, allowing many optical
conversion units to be easily held and stored. Furthermore,
exclusively the distal end of a light source apparatus may be
replaced. Hence, even when, for example, the light source apparatus
is incorporated into an endoscope or the like, the fourth
embodiment enables a replacement operation to be performed more
easily than the first to third embodiments.
[0143] The fourth embodiment illustrates the example in which the
connection portion 48 is located between each of the holding
members 28-8, 28-9, and 28-10 and the ferrule 30 as shown in FIG.
10. However, the fourth embodiment is not limited to this example.
For example, as shown in FIG. 12, a holding member 28-11 and each
of the phosphor 26-1 and a phosphor 26-2, which are optical
conversion elements, may be configured to be attachable to and
removable from each other. That is, a connection portion 54 may be
provided between the optical conversion element (26-1 or 26-2) and
the holding member 28-11. Only an area of FIG. 12 enclosed by a
dotted line is drawn as a cross-sectional view. The connection
portion 54 may include a connection surface 56 which is a part of
the outer surface of the optical conversion element and which
corresponds to one side of the connection portion 54, and a
connection surface 58 that is the inner surface of the holding
member 28-11. In this case, a light source unit 10-6 includes the
semiconductor laser 18-1, the optical fiber 20, the ferrule 30, and
the holding member 28-11. An eleventh optical conversion unit 12-11
and a twelfth optical conversion unit 12-12 each include only an
optical conversion element (26-1 or 26-2, respectively). This
arrangement allows the optical conversion units 12-11 and 12-12 for
replacement to be configured using the minimum amount of members.
Furthermore, the optical conversion units can be configured to have
a very small size. Although not shown in the drawings, the
connection surface 56 of each of the optical conversion units 12-11
and 12-12 has its size defined to fit the connection surface 58 of
the holding member 28-11 or has a fitting structure that fits and
holds the connection surface 58, and is thus prevented from being
inadvertently detached from the connection surface 58.
[0144] Many modifications of the optical conversion unit other than
the above-described examples may be used such as the first to
seventh optical conversion units 12-1 to 12-7, described in the
first to third embodiments, a wavelength selection filter, and a
combination thereof.
Fifth Embodiment
[0145] Now, a fifth embodiment of the present invention will be
described.
[0146] The basic configuration of the present embodiment is the
same as the basic configuration of the first embodiment. Here, only
differences from the first embodiment will be described.
[0147] A light source system according to the fifth embodiment is
different from the light source systems according to the first to
fourth embodiments in the position of a connection portion to and
from which a light source unit and an optical conversion unit are
attached and removed.
[0148] That is, as shown in FIG. 13, the light source system
according to the present embodiment is different from the light
source system according to the first embodiment in that a
connection portion 60 is provided between a semiconductor laser
18-1 or 18-2 and an optical fiber 20 serving as a light guide
rather than on an optical fiber 20.
[0149] A seventh light source unit 10-7 and an eighth light source
unit 10-8 and a thirteenth optical conversion unit 12-13, a
fourteenth optical conversion unit 12-14, and a fifteenth optical
conversion unit 12-15 are different from the first and second light
source units 10-1 and 10-2 and the first, second, and third optical
conversion units 12-1, 12-2, and 12-3 illustrated in the first
embodiment only in the position and structure of the connection
portion. The above-described units of the fifth embodiment have the
same optical functions as those of the corresponding
above-described units of the first embodiment.
[0150] Each of the seventh and eighth light source units 10-7 and
10-8 includes a semiconductor laser 18-1 or 18-2, respectively, the
optical fiber 20 and a connector 62 of the connection portion 60 as
shown in FIG. 13. Although the connection portion 60 is partly
omitted from FIG. 13 for simplification, a connector 62 and a
connector 64 have a fitting structure such as a joint which allows
the connectors 62 and 64 to be fixed to each other.
[0151] The connection portion 60 has a positioning function to
place the ferrule 30 in the optimum positional relationship with
the semiconductor laser 18-1 or 18-2. A lens or the like may be
used to optically connect the ferrule 30 to the semiconductor laser
18-1 or 18-2. In this case, the connection portion 60 has a
positioning function to place the lens in the optimum positional
relationship with the ferrule 30.
[0152] FIG. 13 shows the thirteenth, fourteenth, and fifteenth
optical conversion units 12-13, 12-14, and 12-15, which are members
belonging to a light source unit group according to the present
embodiment.
[0153] The structure of an optical output end side of each of the
thirteenth, fourteenth, and fifteenth optical conversion units
12-13, 12-14, and 12-15 is similar to the structure in the first
embodiment. The thirteenth, fourteenth, and fifteenth optical
conversion units 12-13, 12-14, and 12-15 are similar to the first,
second, and third optical conversion units 12-1, 12-2, and 12-3
according to the first embodiment except that the connection
portion 60 is configured to be suitable for direct connection to
the seventh and eighth light source units 10-7 and 10-8.
[0154] The connection portion 60 is configured such that the
external shape of the ferrule fits the inner diameter of a
through-hole in the connector 62 so that the ferrule 30 is
positioned to efficiently receive primary light emitted by the
semiconductor laser 18-1 or 18-2 of the seventh or eighth light
source unit 10-7 or 10-8. When the ferrule 30 and the connector 62
are fitted together and the distal end of the optical fiber 24 is
positioned to efficiently receive the primary light, the connectors
62 and 64 are fixed to each other. This adjustably allows the
primary light to be more efficiently transmitted through the
connection portion 60.
[0155] For all possible combinations of the members belonging to
the light source unit group and the members belonging to the
optical conversion unit group, the basic operation of the light
source system according to the fifth embodiment described above is
similar to the basic operation described in the first
embodiment.
[0156] As described above, the light source system according to the
fifth embodiment allows the structures of the light source units
10-7 and 10-8 to be simplified without substantially complicating
the structures of the optical conversion units. Thus, the light
source system according to the fifth embodiment is suitable for a
reduction in size and costs.
[0157] That is, the configuration according to the present
embodiment enables a reduction in the sizes and costs of the light
source units 10-7 and 10-8. Furthermore, exclusively the
semiconductor laser 18-1 or 18-2, serving as a primary light
source, can be replaced. For example, even when the light source
apparatus is incorporated into an endoscope or the like, the fifth
embodiment enables a replacement operation to be performed more
easily than the first to third embodiments. In particular, if
lighting is to be provided, for example, under water, a waterproof
structure is easily constructed because the connection portion 60
is not located on the distal end side of the optical fiber 24.
[0158] Many modifications of the optical conversion unit other than
the above-described examples may be used such as the first to
seventh optical conversion units 12-1 to 12-7, described in the
first to third embodiments, a wavelength selection filter, and a
combination thereof.
Modification of the First to Fifth Embodiments
[0159] Now, a modification of the first to fifth embodiments will
be described.
[0160] The first to fifth embodiments illustrate only the examples
in which the optical fibers 20 and 24 as a light guide. However,
the light guide is not limited to the optical fibers, and any of
various common light guides may be used. The various available
light guides include, for example, a film light guide formed by
areas with different refractive indices provided on a film
substrate in contact with one another, a semiconductor light guide
formed by areas with different refractive indices provided on a
semiconductor substrate in contact with one another, and a slab
light guide formed of resin or the like.
[0161] FIG. 14 is a diagram showing the modification of the first
embodiment. FIG. 14 shows an example in which the first light
source unit 10-1 and the optical fiber 20 and 24 used for the first
optical conversion unit 12-1 are replaced with film light guides 66
and 68. For a ninth light source unit 10-9 and a sixteenth optical
conversion unit 12-16, the connection portion 22 and the connectors
14 and 16, which are the components of the connection portion 22,
are replaced with a connection portion 70 and connectors 72 and 74
to allow the use of the film light guides 66 and 68. Furthermore,
the ferrule 30 is replaced with a light guide end holding member
76.
[0162] As shown in FIG. 15, each of the film light guides 66 and 68
includes a light guiding portion 80 formed of a transparent member
having a higher refractive index than a film substrate 78 and a
transparent cover member 82 disposed on the light guiding portion
80 and having a refractive index approximately equal to the
refractive index of the film substrate 78. This configuration
hinders light entering the light guiding portion 80 from
propagating to the film substrate 78 or the cover member 82 and
enables the light to be efficiently guided.
[0163] The connection portion 70 may be based on a normal technique
such as connectors to and from which film light guides can be
attached and removed.
[0164] Moreover, if light guides other than the film light guides
such as semiconductor light guides or slab light guides are used,
the appropriate technique may be selected for the connection
portion.
Sixth Embodiment
[0165] Now, a configuration of a light source system according to a
sixth embodiment of the present invention will be described.
[0166] As shown in FIG. 16, the light source system according to
the present embodiment includes a tenth light source unit 10-10, a
plurality of integrated optical conversion units 84-1, 84-2, and
84-3. A light source apparatus can be provided by combining the
tenth light source unit 10-10 with one of the integrated optical
conversion units 84-1, 84-2, and 84-3.
[0167] The tenth light source unit 10-10 includes two semiconductor
lasers 18-1 serving as a primary light source, optical fibers 20
each serving as a first light guide, and a multi-core connector 88
which is included in an integrated connection portion 86 and which
is a light source unit side connector serving as a first integrated
connection portion. The multi-core connector 88 can be attached to
and removed from an opposite multi-core connector 90 serving as a
second integrated connection portion on the integrated optical
conversion unit 84-1, 84-2, or 84-3 side.
[0168] The semiconductor laser 18-1 is a blue semiconductor laser
that emits blue light with a wavelength of about 450 nm. The blue
semiconductor laser 18-1 and the optical fiber 20 are optically
connected together by a lens or the like (not shown in the
drawings) and configured such that blue laser light that is primary
light emitted by the semiconductor laser 18-1 efficiently enters a
core of the optical fiber 20. The blue laser light having entered
the optical fiber 20 is guided via the integrated connection
portion 86 to the optical conversion unit of the integrated optical
conversion unit 84-1, 84-2, or 84-3 connected to the integrated
connection portion 86.
[0169] Each of the integrated optical conversion units 84-1, 84-2,
and 84-3 includes two optical conversion units. Each of the two
optical conversion units includes a ferrule 30, two holding members
28-1 or two holding members 28-2 or a holding member 28-1 and a
holding member 28-2, and optical conversion elements mounted in the
holding members 28-1 and/or 28-2. The two optical conversion units
are fixed to one optical conversion unit holding member 92-1, 92-2,
or 92-3 to form an integrated optical conversion unit 84-1, 84-2,
or 84-3, respectively. Furthermore, a plurality of connection
portions provided at a proximal end of a second optical fiber 24
connected to the optical conversion unit and serving as a light
guide is aggregated into a second integrated connection portion
(multi-core connector 90) as described above.
[0170] As shown in FIG. 17A, the first integrated optical
conversion unit 84-1 includes two first optical conversion units
12-1 mounted on the optical conversion unit holding member 92-1.
Each of the two first optical conversion unit 12-1 includes a
holding member 28-1, a phosphor 26-1, and a ferrule 30. The holding
member 28-1 is shaped like a bottomed cylinder in which the
phosphor 26-1 is interposed, and the phosphor 26-1 is a wavelength
conversion member carrying out an optical conversion so as to shift
to longer the peak wavelength of the primary light and to broaden
the spectrum shape and the radiation angle. Furthermore, an opening
through which the primary light passes is formed on a bottom
surface of the cylinder of the holding member 28-1. The ferrule 30
and the optical fiber 24 disposed in the ferrule 30 and serving as
a second light guide are inserted through the opening.
[0171] Furthermore, as shown in FIG. 17B, the second integrated
optical conversion unit 84-2 is configured similarly to the first
integrated optical conversion unit 84-1. The second integrated
optical conversion unit 84-2 is different from the first integrated
optical conversion unit 84-1 in the holding member 28-2 with two
optical conversion units and an optical conversion element
interposed in the holding member 28-2. An optical conversion
element in a second optical conversion unit 12-2 of the integrated
optical conversion unit 84-2 is a radiation angle conversion
element including a diffusion member 32 interposed in the holding
member 28-2 and diffusing the primary light.
[0172] As shown in FIG. 17C, the third integrated optical
conversion unit 84-3 includes the first optical conversion unit
12-1 with the phosphor 26-1 mounted on the first integrated optical
conversion unit 84-1 and the second optical conversion unit 12-2
with the diffusion member 32 mounted on the second integrated
optical conversion unit 84-2.
[0173] As shown in FIG. 18, the integrated connection portion 86
includes the multi-core connector 88 serving as a first integrated
connection portion and the multi-core connector 90 serving as a
second integrated connection portion. The multi-core connector 88
mounted on the light source unit 10-10 side includes the optical
fibers 20 connected to the respective blue semiconductor lasers
18-1 and first connection portions 94 attached to the distal ends
of the respective optical fibers 20. The two first connection
portions 94 are attached to a common connection portion holding
member 96 to form a multi-core connector 88 serving as a first
integrated connection portion.
[0174] Similarly, the integrated optical conversion unit side
multi-core connector 90 includes the optical fibers 24 and second
connection portions 98 attached to the proximal ends of the
respective optical fibers 24. The two second connection portions 98
are attached to a common connection portion holding member 100 to
form a multi-core connector 90 serving as a second integrated
connection portion.
[0175] The multi-core connectors 88 and 90 are configured so as to
fix, by a fitting portion (not shown in the drawings), the optical
fibers 20 and 24 at positions where the optical fibers are
efficiently optically connected together. The fitting portion may
be based on a common optical connector technique. Furthermore, for
example, a multi-core ferrule may be used which is like a plurality
of integrated connection portions.
[0176] Now, the operation of the light source system according to
the present embodiment will be described.
[0177] As described above, the light source system allows the
plurality of integrated optical conversion units 84-1, 84-2, or
84-3 to be replaced for the tenth light source unit 10-10.
[0178] First, the operation of a combination of the tenth light
source unit 10-10 with the first integrated optical conversion unit
84-1 will be described.
[0179] The tenth light source unit 10-10 and the first integrated
optical conversion unit 84-1 are connected together by the
integrated connection portion 86. The semiconductor lasers 18-1
mounted on the tenth light source unit 10-10 are allowed to emit
light. Then, blue laser light emitted by the semiconductor lasers
18-1 is delivered to the phosphor 26-1 of the first optical
conversion units 12-1 through the integrated connection portion 86
and the second optical fibers 24. The phosphors 26-1 have its
thickness and fluorescent material content adjusted so as to absorb
a portion of the blue laser light to convert the portion into
yellow light while transmitting the remaining portion of the blue
laser light so that the yellow light resulting from the conversion
and the transmitted blue light form white light. Therefore, when
the blue laser light emitted by the semiconductor lasers 18-1 is
delivered to the phosphors 26-1, white light is emitted as
illumination light.
[0180] According to the present embodiment, the two semiconductor
lasers 18-1 of the light source unit 10-10 are configured to have
the same characteristics, and the two first optical conversion
units 12-1 of the first integrated optical conversion unit 84-1 are
configured to have the same characteristics. Thus, regardless of
whether the two semiconductor lasers 18-1 are turned on or any one
of the two semiconductor lasers 18-1 is turned on, the properties
of emitted white light are the same. However, the irradiation
pattern or intensity distribution of delivered white light can be
adjusted based on the manner of lighting the two semiconductor
lasers 18-1. Furthermore, the system may be designed such that an
irradiation pattern or intensity distribution suitable for an
illumination target can be obtained by adjusting a mounting portion
on the optical conversion unit holding member 92-1 which allows the
first optical conversion units 12-1 to be mounted thereon.
Additionally, operation of each of the semiconductor lasers up to a
brightness limit allows the resultant brightness to be doubled
compared to operation of only one of the semiconductor lasers up to
the brightness limit.
[0181] Now, the operation of a light source apparatus with a
combination of the tenth light source unit 10-10 with the second
integrated optical conversion unit 84-2 will be described. The
basic operation of this light source apparatus is similar to the
basic operation of the above-described light source apparatus using
the first integrated optical conversion unit 84-1.
[0182] The optical conversion elements of the second optical
conversion units 12-2 mounted on the second integrated optical
conversion unit 84-2 are the diffusion members 32. The diffusion
member 32 has the property of broadening the radiation angle of
blue laser light emitted by the semiconductor laser 18-1.
Furthermore, upon passing through the diffusion member 32, the
laser light has its coherence length reduced and is hindered from
forming speckles or the like on the illumination target. Thus, with
this combination, turning on of the semiconductor lasers 18-1
enables emission of blue laser light, which has a divergence angle
suitable for illumination of the target and which is unlikely to
form speckles and the like.
[0183] Now, the operation of a light source apparatus with a
combination of the tenth light source unit 10-10 with the third
integrated optical conversion unit 84-3 will be described. The
basic operation of this light source apparatus is similar to the
basic operations of the above-described light source apparatuses
using the first and second integrated optical conversion units 84-1
and 84-2.
[0184] The optical conversion elements of the first and second
optical conversion units 12-1 and 12-2 mounted on the third
integrated optical conversion unit 84-3 are one phosphor 26-1 and
one diffusion member 32. When the semiconductor laser 18-1
optically connected to the phosphor 26-1 is turned on, the first
optical conversion unit 12-1 emits white light. Furthermore, when
the semiconductor laser 18-1 optically connected to the diffusion
member 32 is turned on, the second optical conversion units 12-2
emits diffused blue illumination light.
[0185] As described above, the light source system according to the
sixth embodiment allows illumination light suitable for
illuminating various intended illumination targets to be obtained
by replacing only the integrated optical conversion unit 84-1,
84-2, or 84-3 for the tenth light source unit 10-10. Furthermore,
according to the light source system according to the sixth
embodiment, a plurality of optical conversion units is integrated
into the integrated optical conversion unit 84-1, 84-2, or 84-3 to
enable design of an irradiation pattern and provision of a brighter
light source apparatus. Additionally, the use of the third
integrated optical conversion unit 84-3 with two different optical
conversion units enables the illumination light to be
instantaneously switched by turning the semiconductor lasers on and
off. In this case, a plurality of connection portions is integrated
into the integrated connection portion 86 and is thus
simultaneously attachable and removable.
[0186] That is, the light source system according to the sixth
embodiment allows the plurality of integrated optical conversion
units 84-1, 84-2, and 84-3 to be replaced for one light source unit
10-10, thus enabling a small number of members to generate more
types of illumination light.
[0187] Furthermore, when a plurality of optical conversion units is
integrated into the integrated optical conversion unit 84-1, 84-2,
or 84-3, the irradiation pattern can be designed according to the
illumination target, a brighter light source apparatus can be
provided, and a light source apparatus can be provided which allows
different illumination light colors to be instantaneously switched
by turning the light sources on and off. In this case, a plurality
of connection portions is integrated into the integrated connection
portion 86 and is thus easily simultaneously attachable and
removable without erroneous connection.
[0188] In the above-described sixth embodiment, the system includes
the one type of light source unit and the three types of integrated
optical conversion units for simplification. However, for practical
use, more light source units and more integrated optical conversion
units may be appropriately prepared according to the demanded
functions of the illumination light. The primary light source
mounted on the light source unit is not limited to the
semiconductor laser 18-1 but may be any of various light sources
such as various laser light sources, a LED, and a lamp. More
desirably, the light source is efficiently connectible to the
optical fiber.
[0189] Furthermore, the optical conversion element mounted on the
optical conversion unit is also not limited to the above-described
phosphor or diffusion member but may be any of various optical
conversion elements. Examples of the usable optical conversion
element include not only various powdery phosphors, ceramic
phosphors, and single crystal phosphors, but also a quantum dot, a
semiconductor light emitting element, and an organic light emitting
element. Additionally, when a filter that cuts a portion of the
wavelength of fluorescence is disposed on an output surface of the
phosphor, exclusively the fluorescence in the desired wavelength
region can be extracted. Alternatively, mounting a filter that cuts
the primary light enables only the fluorescence to be extracted.
Furthermore, the diffusion member may be of a type including a
transparent member the surface of which is processed to include
recesses and protrusions. Moreover, when various optical conversion
units are used such as a lens group configured to adjust the
radiation angle, a diffraction grating, a polarizing element, and a
photonic crystal, the radiation angle or intensity distribution of
emitted secondary light can be optimized or made directional. In
addition, the use of various wavelength filters enables only the
light in the desired wavelength range to be extracted or cut.
Seventh Embodiment
[0190] Now, a seventh embodiment of the present invention will be
described.
[0191] The basic configuration of the seventh embodiment is the
same as the basic configuration of the sixth embodiment. Thus, only
differences from the sixth embodiment will be described.
[0192] The light source system according to the present embodiment
is configured as shown in FIG. 19 and basically configured
similarly to the light source system in the sixth embodiment shown
in FIG. 16. The seventh embodiment is different from the sixth
embodiment in the number of primary light sources in a light source
unit, the number of optical conversion units in an integrated
optical conversion unit, and the number of connection portions in
an integrated connection portion.
[0193] That is, the present embodiment illustrates an example of an
integrated optical conversion unit group with integrated optical
conversion units. In the integrated optical conversion unit group,
when effective light source unit side connection portions are
defined as those of the connection portions of a first integrated
connection portion provided on a light source unit which are
optically connected to a primary light source and effective optical
conversion unit side connection portions are defined as those of
the connection portions of a second integrated connection portion
provided on an integrated optical conversion unit which are
optically connected to optical conversion units, the effective
light source side connection portions are different, in number,
from the effective optical conversion unit side connection
portions. The present embodiment describes an example of an
integrated optical conversion unit group with integrated optical
conversion units in which the effective optical conversion unit
connection portions are fewer than the effective light source side
connection portions.
[0194] As shown in FIG. 19, the light source unit according to the
present embodiment is an eleventh light source unit 10-11 with two
semiconductor lasers 18-1 and two semiconductor lasers 18-2 in
which the semiconductor lasers 18-1 and 18-2 are of different
types. The eleventh light source unit 10-11 includes the
semiconductor lasers 18-1, which emit 450-nm blue laser light as is
the case with the sixth embodiment, and the semiconductor lasers
18-2, which are different from the semiconductor lasers 18-1 and
emit 405-nm blue-violet laser light. A first optical fiber 20 is
connected to each of the total of four semiconductor lasers 18-1
and 18-2 and to a multi-core connector 102 serving as a first
integrated connection portion. That is, the multi-core connector
102 includes four connection portions. In other words, a connection
portion holding member 96 provided on the light source unit 10-11
includes four connection portion mounting positions to all of which
connection portions are mounted.
[0195] The remaining part of the configuration is similar to the
corresponding part of the sixth embodiment.
[0196] On the other hand, the integrated optical conversion unit
according to the present embodiment includes three integrated
optical conversion units 84-4, 84-5, and 84-6 as members. The
fourth integrated optical conversion unit 84-4 includes a total of
four optical conversion units including two holding members 28-1
each with a phosphor 26-1 interposed therein as is the case with
the sixth embodiment and two holding member 28-16 each with a
phosphor 26-5 mounted thereon to optically convert 405-nm
blue-violet light into red light. The four optical conversion unit
12-1 and 12-16 are fixed to one optical conversion unit holding
member 92-4. Furthermore, the fourth integrated optical conversion
unit 84-4 includes a multi-core connector 104 serving as a second
integrated connection portion with four connection portions. Four
optical fibers 24 extending from the respective connection portions
are connected to respective holding members 28-1 and 28-2.
[0197] Furthermore, the fifth integrated optical conversion unit
84-5 includes only the two first optical conversion units 12-1,
including the phosphors 26-1 and included in the four optical
conversion units mounted on the fourth integrated optical
conversion unit 84-4. The two first optical conversion units 12-1
are fixed to one optical conversion unit holding member 92-5.
Additionally, the fifth integrated optical conversion unit 84-5
includes the multi-core connector 104 serving as a second
integrated connection portion with four connection portions. Second
optical fibers 24 are connected to ports optically connected to two
of the four connection portions of the multi-core connector that
are connected to the semiconductor lasers 18-1 of the light source
unit 10-11. Each of the second optical fibers 24 extends to the
corresponding optical conversion unit with the phosphor 26-1
mounted thereon. In addition, each of the two remaining ports
includes a shutter 106 serving as a light blocking member that
prevents laser light from leaking to the exterior. That is, the
number of effective connection portions is two. Here, the number of
effective connection portions refers to the number of connection
portions each with the distal end thereof connected to the optical
conversion unit and does not involve apparent connection portions
with no actual connection. In other words, the connection portion
holding member 100 includes four connection portion attachable
positions so that the connection portions are attached at two of
these positions, whereas the shutters 106 are attached at the
remaining two positions.
[0198] Furthermore, the sixth integrated optical conversion unit
84-6 includes a total of two optical conversion units included in
the four optical conversion units mounted on the fourth integrated
optical conversion unit 84-4, the two optical conversion units
including one first optical conversion unit 12-1 with the phosphor
26-1 and one sixteenth optical conversion unit 12-16 with the
phosphor 26-5. The two optical conversion units 12-1 and 12-6 are
fixed to one optical conversion unit holding member 92-6.
Additionally, the sixth integrated optical conversion unit 84-6
includes the multi-core connector 104 serving as a second
integrated connection portion with four connection portions. Second
optical fibers 24 are connected to a total of two connection ports,
that is, one of those two connection portions of the four
connection portions of the multi-core connector 104 which are
connected to the semiconductor lasers 18-1 of the light source unit
10-11 and to one of those two connection portions of the four
connection portions of the multi-core connector 104 which are
connected to the semiconductor lasers 18-2 of the light source unit
10-11. Each of the second optical fibers 24 extends to the
corresponding optical conversion unit with the phosphor 26-1 or
26-5. In addition, each of the two remaining ports includes the
shutter 106 serving as a light blocking member that prevents laser
light from leaking to the exterior. That is, the number of
effective connection portions is two. In other words, the
connection portion holding member 100 includes four connection
portion attachable positions so that the connection portions are
attached at two of these positions, whereas the shutters 106 are
attached at the two remaining positions.
[0199] The appropriate design according to the purpose can be
applied to the arrangement of the individual optical conversion
units on the optical conversion unit holding members 92-4, 92-5,
and 92-6 in the integrated optical conversion units 84-4, 84-5, and
84-6. FIG. 20A shows an example of a configuration using, for
example, a cylindrical optical conversion unit holding member
92-4-A, and FIG. 20B shows an example of a configuration using, for
example, a plate-like optical conversion unit holding member
92-4-B. The example of the fourth integrated optical conversion
unit 84-4-A shown in FIG. 20A is suitable for illuminating the
interior of a thin hole or the like. The example of the fourth
integrated optical conversion unit 84-4-B shown in FIG. 20B is
suitable for illuminating the interior of a thin crack-like gap.
Thus, even the integrated optical conversion units 84-4, 84-5, 84-6
with the same optical conversion unit mounted thereon allows the
size and shape of the distal end unit to be made suitable for the
purpose by changing an attachment position on the optical
conversion unit holding member 92-4, 92-5, or 92-6. Furthermore,
the shape of the irradiation pattern delivered to the illumination
target can be made suitable for the purpose.
[0200] Now, the operation of the light source system according to
the seventh embodiment will be described. The operation is
basically the same as the operation of the light source system
according to the sixth embodiment. Here, only differences from the
sixth embodiment will be described.
[0201] First, the operation of a light source apparatus with a
combination of the eleventh light source unit 10-11 with the fourth
integrated optical conversion unit 84-4 will be described.
[0202] Blue laser light emitted by the semiconductor lasers 18-1 is
guided to the phosphors 26-1 via the optical fibers 20 and 24. The
phosphors 26-1 convert a portion of the blue laser light into
yellow fluorescence while transmitting the remaining portion, to
emit white light. The spectrum of the emitted white light is shown
in FIG. 21. In FIG. 21, a spectrum resulting from turning on of the
blue semiconductor lasers 18-1 contains blue laser light 108 and
yellow fluorescence 110. The corresponding illumination light
appears to be white light, but light of a red component which is
600 nm or more in wavelength is weak.
[0203] Blue-violet laser light emitted by the semiconductor lasers
18-2 is guided to the phosphors 26-5 via the optical fibers 20 and
24. The phosphors 26-5 convert a portion of the blue-violet laser
light into red fluorescence. In FIG. 21, a spectrum resulting from
turning on of the blue-violet semiconductor lasers 18-2 contains
blue-violet laser light 112 and red fluorescence 114. The present
embodiment illustrates the example in which the phosphors 26-5
absorb a portion of the blue-violet laser light 112 to convert the
portion into red fluorescence 114 while transmitting the remaining
portion. However, the phosphors 26-5 may be configured to convert
all of the blue-violet laser light 112 into the red fluorescence
114.
[0204] That is, when both the semiconductor lasers 18-1 and 18-2
are turned on, the spectrum of illumination light emitted by the
fourth integrated optical conversion unit 84-4 contains the
blue-violet laser light 112, the blue laser light 108, and
fluorescence 16 with the yellow fluorescence 110 and the red
fluorescence 114 overlapping each other as shown in FIG. 21.
[0205] Now, the operation of a combination of the light source unit
10-11 with the fifth integrated optical conversion unit 84-5 will
be described.
[0206] An operation resulting from turning on of the semiconductor
lasers 18-1 is similar to the operation associated with a
combination of the light source unit 10-10 with the first
integrated optical conversion unit 84-1 according to the sixth
embodiment.
[0207] On the other hand, when the semiconductor lasers 18-2 is
turned on, blue-violet laser light is fed from a connection portion
of the multi-core connector 102 with the light source unit 10-11
which portion is connected to the semiconductor lasers 18-2 to a
connection portion of the multi-core connector 104 of the fifth
integrated optical conversion unit 84-5 which portion has no
connection. However, the connection portion with no connection
includes the shutters 106 serving as a light blocking member that
prevents laser light from leaking to the exterior, thus blocking
the laser light by the shutters 106 to prevent the laser light from
leaking to the exterior.
[0208] Now, the operation of a combination of the light source unit
10-11 with the sixth integrated optical conversion unit 84-6 will
be described.
[0209] An operation resulting from turning on of the semiconductor
lasers 18-1 and 18-2 on the light source unit 10-11 optically
connected to the phosphors 26-1 and 26-5 via the multi-core
connectors 102 and 104 is basically similar to the operation
associated with the connection between the light source unit 10-11
and the fourth integrated optical conversion unit 84-4 as described
above. In the above-described example, two semiconductor lasers
18-1 are combined with two optical conversion units with the
respective phosphors 26-1, and two semiconductor lasers 18-2 are
combined with two optical conversion units with the respective
phosphors 26-5. When the light source unit 10-11 is combined with
the sixth integrated optical conversion unit 84-6, one
semiconductor laser 18-1 is combined with one optical conversion
unit with the phosphor 26-1, and one semiconductor laser 18-2 is
combined with one optical conversion unit with the phosphor 26-5,
but the operation is similar to the operation in the
above-described example.
[0210] Furthermore, the operation of a connection portion of the
multi-core connector 102 of the light source unit 10-11 which
portion has no connection is similar to the above-described
operation associated with the fifth integrated optical conversion
unit 84-5. Laser light delivered to the shutters 106 is absorbed by
the shutters 106 and prevented from leaking to the exterior.
[0211] As described above, in the light source system according to
the seventh embodiment, different primary light sources are mounted
on one light source unit 10-11, different numbers of optical
conversion units with different functions are mounted on the
integrated optical conversion units 84-4, 84-5, and 84-6, and
various types of needed illumination light can be provided by
appropriately combining the light source unit with any of the
integrated optical conversion units.
[0212] That is, the present embodiment allows any of the integrated
optical conversion units 84-4, 84-5, and 84-6 to be selected
according to the characteristics of needed illumination light. That
is, in the configuration according to the sixth embodiment, the
light of the red component is slightly weaker than the other
colors, and the weak light of the red component may pose a problem
depending on the illumination target. For example, when a red
object is to be illuminated, illumination light with few red
components makes the object appear dark. The configuration
according to the present embodiment may combine the light source
unit 10-11 with the fourth integrated optical conversion unit 84-4
for applications needing bright red components and may use the
fifth integrated optical conversion unit 84-5 for applications not
emphasizing red components. The fifth integrated optical conversion
unit 84-5 includes only a small number of, that is, two optical
conversion units mounted thereon and can thus be small and
inexpensive. Furthermore, if brightness is unwanted but red
components are needed, the needed light can be obtained by using
the sixth integrated optical conversion unit 84-6. The sixth
integrated optical conversion unit 84-6 is also small and
inexpensive.
[0213] Thus, an illumination apparatus corresponding to an
application can be provided using the common light source unit
10-11.
[0214] The present embodiment illustrates the example in which the
light source unit includes two primary light sources mounted
thereon and emitting one type of light and two other primary light
sources mounted thereon and emitting a different type of light.
However, the present embodiment is not limited to this example.
Three or more types of primary light sources may be mounted on the
light source unit depending on the application. Such a
configuration can provide a brighter light source apparatus and
implement illumination light in more colors and with different
spectra.
[0215] Furthermore, the present embodiment illustrates the example
in which the connection portion uses four-core connectors. However,
the present embodiment is not limited to this example. At least two
cores enable different types of illumination light to be
implemented according to the connection. Additionally, at least
five cores enable more different types of illumination light to be
implemented.
[0216] Moreover, the present embodiment illustrates the example in
which the color rendering index for red is improved by adding red
fluorescence to yellow fluorescence. The present embodiment is not
limited to this example. For example, the intensity of a blue
component can be improved by using a phosphor that converts 405-nm
blue-violet laser light into blue. This allows a blue object to be
brightly illuminated.
[0217] According to such a light source system, for a user who does
not particularly need brightness and who is to utilize white light
and white light with a red component added thereto, a small,
inexpensive illumination apparatus can be implemented by providing
a light source unit with a reduced number of primary light
sources.
[0218] A twelfth light source unit 10-12 shown in FIG. 22 includes
one semiconductor laser 18-1 emitting blue light and one
semiconductor laser 18-2 emitting blue-violet light. The multi-core
connector 102 serving as a first integrated connection portion is
connectible to any of the integrated optical conversion units 84-4,
84-5, and 84-6 illustrated in the seventh embodiment. In a
combination of the twelfth light source unit 10-12 with the sixth
integrated optical conversion unit 84-6, white light can be
obtained by turning only the semiconductor laser 18-1 on, and the
red component can be added to the white color by further turning
the semiconductor laser 18-2 on. In this case, the number of
effective connection portions is two. Furthermore, two ineffective
connection portions include the shutter 106 as a cover. In other
words, the connection portion holding portion 96 includes four
connection portion mountable positions so that the connection
portions are attached at two of these positions, whereas the
shutters 106 are attached at the remaining two positions.
[0219] Furthermore, if brighter illumination light is needed for
the future, the light source can be stepped up by purchasing the
eleventh light source unit 10-11 and the fourth integrated optical
conversion unit 84-4. In this case, the already owned sixth
integrated optical conversion unit 84-6 can be continuously
used.
[0220] Moreover, a user who owns the eleventh light source unit
10-11 and a plurality of integrated optical conversion units can
utilize such a small light source unit 10-12 as a reserve or handy
light source unit.
[0221] That is, the eleventh light source unit 10-11 and the
twelfth light source unit 10-12 form a light source unit group. The
user can obtain a light source unit meeting the user's purpose from
the light source unit group or add the light source unit group to
the user's owned light source system.
[0222] Now, a modification of the light source unit according to
the seventh embodiment will be described.
[0223] The present modification illustrates a configuration of a
light source unit configured differently from the above-described
light source units and which can be combined, for use, with any of
the integrated optical conversion units 84-4, 84-5, and 84-6
described in the seventh embodiment.
[0224] The eleventh light source unit 10-11 described in the
seventh embodiment uses four semiconductor lasers, that is, the two
semiconductor lasers 18-1 emitting blue light and the two
semiconductor lasers 18-2 emitting blue-violet light. As shown in
FIG. 23, a thirteenth light source unit 10-13 according to the
present modification includes one semiconductor laser 18-1 and one
semiconductor laser 18-2. The thirteenth light source unit 10-13 is
combined with a 1.times.2 optical coupler 118 with one input end
and two output ends to allow blue light and/or blue-violet light to
be emitted through a connection port of the multi-core connector
102 serving as a first integrated connection portion. That is, a
part of the light guide corresponding to the optical fiber 20 is
replaced with the optical coupler 118. The optical coupler is based
on a common optical fiber technique and produced by a method for
optical coupling of a core portion of the optical fiber.
[0225] In such a configuration, laser light emitted by the
semiconductor lasers 18-1 and 18-2 enters input ends of the optical
couplers 118, where the light is split into two light beams in the
respective optical paths. The light beams are then emitted through
two of the four connection portions of the multi-core connector
102. The subsequent operation is similar to the corresponding
operation according to the seventh embodiment.
[0226] Such a configuration allows a reduced number of
semiconductor lasers to emit illumination light through an
increased number of optical conversion units in the integrated
optical conversion unit 84-4, 84-5, or 84-6.
[0227] This enables an increase in the number of light emission
points in the integrated optical conversion unit to be increased
above the number of semiconductor lasers. As a result, for example,
when a close illumination target is to be illuminated, an
illumination light output portion may be arranged so as to hinder
shading. Furthermore, a reduced number of semiconductor lasers
enable a compact light source unit to be inexpensively
provided.
[0228] The present modification illustrates the example using the
1.times.2 optical coupler 118. However, the present modification is
not limited to this example. For example, the use of a 1.times.3 or
larger multi-branch type allows the use of an increased number of
optical conversion units. Thus, the illumination pattern can be
more freely designed, for example, so as to hinder shading.
[0229] Alternatively, an optical coupler with a plurality of input
ends may use, and a monitor for optical feedback is connected to
one of the input ends. This allows monitoring of the status of
laser light fed back from the optical conversion unit and light
subjected to optical conversion.
[0230] For example, FIG. 24 shows an example in which a fourteenth
light source unit 10-14 uses a 2.times.2 optical coupler 120 with
two input ends and two output ends. A photodetector 122 is disposed
on one of the two input ends of each of the two optical couplers
120 that is not connected to the semiconductor laser 18-1 or 18-2.
Thus, the photodetector 122 can detect optical feedback, that is,
laser light emitted by the semiconductor laser 10 and fed back to
the emission side after being delivered to the optical conversion
unit optically connected to the semiconductor laser 10, as well as
light subjected to optical conversion.
[0231] Moreover, the modification of the seventh embodiment
illustrates the example in which the optical coupler is provided on
the light source unit 10-13 or 10-14 side. However, the optical
coupler may be used on the integrated optical conversion unit side.
This enables an increase in the number of optical conversion units
in the integrated optical conversion unit without increasing the
number of connection portions.
[0232] Exemplary types of optical conversion units mounted on the
integrated optical conversion unit include not only the exemplary
optical conversion units illustrated in the sixth and seventh
embodiments but also various modifications thereof. For example,
the optical conversion unit may be modified to offer enhanced
thermal resistance to enable stronger primary light to be
converted, or a wavelength conversion filter, a plurality of
phosphors mixed or stacked, or a combination of a plurality of such
optical conversion units may be used.
Modification of the Sixth and Seventh Embodiments
[0233] Now, a modification of the sixth and seventh embodiments
will be described.
[0234] Like the first to fifth embodiments, the sixth and seventh
embodiments allow various light guides to be utilized. In this
case, a plurality of light guides may be formed on one
substrate.
[0235] Similarly, the optical couplers 118 and 120 serving as light
guides are not limited to optically coupled optical fibers, and
optical couplers based on various common light guides may be used.
The various light guides may include the above-described film light
guide, a semiconductor substrate light guide, and a slab light
guide formed of resin.
[0236] Here, as the film light guide, a film light guide 68 as
shown in FIG. 15 may be used.
[0237] FIG. 25 is a perspective view of an example of the optical
coupler 118 based on a film light guide technique as viewed from an
upper surface of the optical coupler 118. Primary light entering an
input end 124 is split into two light beams in the respective
paths. The light beams are then emitted through respective output
ends 128.
[0238] The integrated connection portion 86 may be based on a
normal technique such as connectors to and from which film light
guides can be attached and removed.
[0239] Moreover, if light guides other than the film light guides
such as semiconductor light guides or slab light guides are used,
the appropriate technique may be selected for the connection
portion.
[0240] The present invention has been described based on the
embodiments. However, of course, the present invention is not
limited to the above-described embodiments, and various
modifications and applications may be made to the embodiments
without departing from the scope of the present invention.
[0241] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details, and
representative devices shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
* * * * *