U.S. patent application number 15/070958 was filed with the patent office on 2016-07-07 for light source unit, light source device, and display apparatus.
This patent application is currently assigned to Sony Corporation. The applicant listed for this patent is Sony Corporation. Invention is credited to Norimasa Furukawa, Ichiro Murakami, Hiroshi Murayama.
Application Number | 20160195226 15/070958 |
Document ID | / |
Family ID | 40998099 |
Filed Date | 2016-07-07 |
United States Patent
Application |
20160195226 |
Kind Code |
A1 |
Furukawa; Norimasa ; et
al. |
July 7, 2016 |
LIGHT SOURCE UNIT, LIGHT SOURCE DEVICE, AND DISPLAY APPARATUS
Abstract
A light source unit is used in a multiply combined manner, and
includes a light source element having a substrate and one or more
light emitting elements disposed on the substrate. The light source
unit is configured such that when a plurality of the light source
units are arranged in cascade, the light source element in the
light source unit comes to in electric connection with another
light source element in an adjacent light source unit. Thereby, the
plurality of light source units may emit light at the same time.
Thus, the structure similar to rod-shaped light source such as CCFL
is achieved.
Inventors: |
Furukawa; Norimasa; (Tokyo,
JP) ; Murayama; Hiroshi; (Kanagawa, JP) ;
Murakami; Ichiro; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sony Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
Sony Corporation
Tokyo
JP
|
Family ID: |
40998099 |
Appl. No.: |
15/070958 |
Filed: |
March 15, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12390721 |
Feb 23, 2009 |
9316360 |
|
|
15070958 |
|
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Current U.S.
Class: |
362/84 ;
362/217.17 |
Current CPC
Class: |
F21V 19/0025 20130101;
G02F 1/133603 20130101; F21Y 2103/10 20160801; H01L 2224/48091
20130101; F21K 9/27 20160801; F21V 19/0045 20130101; F21Y 2115/10
20160801; F21K 9/20 20160801; F21Y 2101/00 20130101; H01L
2224/48091 20130101; H01L 2924/00014 20130101 |
International
Class: |
F21K 99/00 20060101
F21K099/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 25, 2008 |
JP |
2008-043369 |
Claims
1. A light source device comprising: a plurality of light source
units, each having one or more light emitting elements and
electrical connection portions, and an arrangement restriction
structure restricting arrangement of the plurality of light source
units so that the plurality of light source units are arranged in
cascade, wherein the plurality of light source units are
electrically connected to one another the respective electrical
connection portions of the light source units, wherein the
arrangement restriction structure is a hollow tube, and the
plurality of the light source units are arranged in cascade within
the hollow tube.
2. The light source device according to claim 1, wherein: the one
or more light emitting elements comprise at least one light
emitting diode.
3. The light source device according to claim 1, wherein: the
arrangement restriction structure is formed of a material that is
transparent to visible light.
4. The light source device according to claim 1, wherein: the one
or more light emitting elements include zinc oxide as a main
material, and the one or more light emitting elements are
configured to emit ultraviolet light.
5. The light source device according to claim 1, further
comprising: one or more non-light-emitting elements inside the
hollow tube, wherein the one or more non-light-emitting elements
separate the plurality of light source units from one another.
6. The light source device according to claim 1, wherein: the
hollow tube comprises an inner fluorescent surface, wherein the
inner fluorescent surface is configured to be excited by light from
the one or more light emitting elements to emit fluorescent light,
and the fluorescent light s emitted to outside the light source
device.
7. The light source device according to claim 6, wherein: the
hollow tube is opaque to ultraviolet light.
8. An apparatus comprising: a plurality of light source units, each
light source unit of the plurality of light source units having one
or more light emitting elements and one or more electrical
connection portions; and an arrangement restriction structure
restricting arrangement of the plurality of light source units so
that the plurality of light source units are arranged in cascade,
wherein at least one first light source unit of the plurality of
light source units is electrically connected to at least one second
light source unit of the plurality of light source units via at
least one electrical connection portion, wherein the arrangement
restriction structure comprises a hollow tube, and wherein the
plurality of the light source units are arranged in cascade within
the hollow tube.
9. The apparatus according to claim 8, wherein: the one or more
light emitting elements comprise at least one light emitting
diode.
10. The apparatus according to claim 8, wherein: the plurality of
light source units are configured to produce light, the apparatus
further comprises a display section having a first side and a
second side, the display section being arranged with respect to the
plurality of light source units so that the light produced by the
plurality of light source units is incident on the first side, and
the display section is configured to alter its transmissivity in
response to an image signal so as to selectively allow the incident
light to pass to the second side and thereby generate an image
corresponding to the image signal.
11. The apparatus according to claim 8, wherein: the arrangement
restriction structure is formed of a material that is transparent
to visible light.
12. The apparatus according to claim 8, wherein: the one or more
light emitting elements include zinc oxide as a main material, and
the one or more light emitting elements are configured to emit
ultraviolet light.
13. The apparatus according to claim 8, further comprising: one or
more non-light-emitting elements inside the hollow tube, wherein
the one or more non-light-emitting elements separate the plurality
of light source units from one another.
14. The apparatus according to claim 8, wherein: the hollow tube
comprises an inner fluorescent surface, wherein the inner
fluorescent surface is configured to be excited by light from the
one or more light emitting elements to emit fluorescent light, and
the fluorescent light is emitted to outside the apparatus.
15. The apparatus according to claim 14, wherein: the hollow tube
is opaque to ultraviolet light.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of and claims the benefit under 35
U.S.C. .sctn.120 of U.S. patent application Ser. No. 12/390,721,
titled "LIGHT SOURCE UNIT, LIGHT SOURCE DEVICE, AND DISPLAY
APPARATUS", filed on Feb. 23, 2009, which claims the benefit under
35 U.S.C. .sctn.119 of Japanese Priority Patent Application
JP2008-043369, filed in the Japanese Patent Office on Feb. 25,
2008, each of which is hereby incorporated herein by reference in
its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a light source unit using,
for example, LED (Light Emitting Diode) as a light emitting
element, to a light source device including a plurality of the
light source units being combined to one another, and to a display
apparatus using the light source device as a backlight.
[0004] 2. Background Art
[0005] A light source using a bar-like fluorescent tube or a
rod-like fluorescent tube such as CCFL (Code Cathode Fluorescent
Lamp) has been known as a light source of a backlight of a liquid
crystal display apparatus and the like. Moreover, a backlight has
been proposed, such as in Japanese Unexamined Patent Application
Publication No. 2001-266605, in which a rod-like ultraviolet lamp
is used as a light source, and in which ultraviolet rays are
converted into visible light for illumination light.
SUMMARY OF THE INVENTION
[0006] Furthermore, recently, a light source using LED (Light
Emitting Diode) has appeared as a light source of a backlight.
Light sources for the backlight include a light source using
respective color LED or R (red), G (green) and B (blue) being
combined into color mixture, and a light source using a single LED
chip for white light emission. Particularly, since it is considered
that the light source using a single LED chip for white light
emission may not require a servo system for color matching, and may
provide a relatively wide color display range, the light source has
been considered to be promising, and now practically used as a
white backlight. In this case, a configuration of the backlight
typically includes a light guide type where light from a light
source, being disposed in a side face direction with respect to an
illumination object, is guided to an illumination object side via a
light guide plate, and a direct type where a light source is
disposed directly below an illumination object. A diffuser plate is
disposed at a light emission side of the backlight for uniforming
illumination light.
[0007] In the case of the light guide type, the backlight is
practically used for a mobile phone or the like through reduction
of thickness of the diffuser plate and the like. In the light guide
type, design of the diffuser plate is devised, thereby the
backlight becomes advantageous for reduction in thickness. However,
the light guide type has a difficulty in a way which allows light
in the light guide to exit from the light guide. Generally, since
operation that light entering the inside of a diffuser plate
through total reflection is emitted to the outside of the plate is
contrary to operation that the light is contained within the plate,
contradiction exists in that point, leading to a disadvantage of
low light-use efficiency. Moreover, since the light guide type has
relatively heavy weight, the light guide type is not frequently
used for a large device. On the other hand, the direct type has
high light-use efficiency, but has a disadvantage that thickness
reduction is difficult.
[0008] In this way, the light guide type and the direct type have
both advantages and disadvantages respectively. In particular, the
direct type, being used for a large liquid crystal TV or the like,
is now necessary to be reduced in thickness, to be increased in
luminance, and to be decreased in unevenness of chromaticity.
[0009] The Japanese Unexamined Patent Application Publication No.
2001-266605 describes an invention where a reflective plate is
disposed outside an ultraviolet lamp, and a fluorescent light
emission plate is disposed on a surface of the reflective plate and
excited by ultraviolet light from the ultraviolet lamp, thereby
fluorescent light emission with high light-use efficiency is made.
In the structure described in Japanese Unexamined Patent
Application Publication No. 2001-266605, ultraviolet rays are used
for excitation light, which are invisible. Moreover, since
mercury-discharge UV fluorescent-light-emission CCFL or the like is
specifically used for an excitation light source, a transparent
glass tube is used. Therefore, in the configuration, the excitation
light source may not make a shadow in observation from an
excitation light illumination side.
[0010] On the other hand, a configuration is considered, where blue
light given by blue LED is used for excitation light, and red and
green phosphors are excited by the blue light, and emitted light
are mixed with the excitation light, so that white light is
obtained. In this case, since the blue LED being the excitation
light source is neither colorless nor transparent unlike the
ultraviolet lamp, if it is simply configured into the direct type,
the light source itself is problematically seen from an
illumination object side. Even if the light source is floated in
the air, a shadow of the light source itself is made at the
excitation light illumination side. Therefore, a configuration that
allows observation of the excitation light illumination side has
not been able to be actually achieved.
[0011] Moreover, a configuration is considered, where ultraviolet
light given by ultraviolet LED is used for excitation light to
obtain white light. LED using GaN (gallium nitride) has been
largely developed as ultraviolet LED in the past. However, LED
using ZnO (zinc oxide) is recently developed. In the ultraviolet
LED using zinc oxide, a light emitting element itself may be
colorless and transparent to visible light. Therefore, ultraviolet
LED using zinc oxide as a main material is used, thereby a
direct-type illumination device may be configured without making a
shadow of a light source itself. However, unlike a rod-shaped light
source such as CCFL, for example, if a flat backlight is intended
to be configured using LED, LED need to be two-dimensionally
arranged, and a circuit board is necessary for establishing wiring
to the LED. If a structure similar to the rod-shaped light source
such as CCFL or the flat backlight is achieved without using such a
circuit board, the structure is practically useful. However, such a
structure is not achieved yet.
[0012] In view of foregoing, it is desired to provide a light
source unit, a light source device, and a display apparatus, which
allow a structure similar to a rod-shaped light source such as CCFL
to be achieved by using point source of light such as LED.
[0013] A light source unit according to an embodiment of the
invention is used in a multiply combined manner, and includes: a
light source element having a substrate and one or more light
emitting elements disposed on the substrate, wherein the light
source unit is configured such that when a plurality of the light
source units are arranged in cascade, the light source element in
the light source unit comes to in electric connection with another
light source element in an adjacent light source unit.
[0014] A light source device according to an embodiment of the
invention includes: a plurality of light source units, each having
one or more light emitting elements and electrical connection
portions, and an arrangement restriction structure restricting
arrangement of the plurality of light source units so that the
plurality of light source units are arranged in cascade, wherein
the plurality of light source units are electrically connected to
one another via the respective electrical connection portions of
the light source units.
[0015] A display apparatus according to an embodiment of the
invention includes: an illumination device; and a display section
displaying an image with use of illumination light from the
illumination device, wherein the illumination device has a
plurality of rod-shaped light sources, each of the rod-shaped light
sources having an optically transparent cylindrical tube with a
hollow space inside thereof and having a plurality of light source
units emitting light, and the light source units are arranged in
cascade inside the optically transparent cylindrical tube, and the
light source units adjacent to each other are electrically
connected to each other.
[0016] In the light source unit according to the embodiment of the
invention, when a plurality of light source units are arranged in
cascade, adjacent light source elements are electrically connected
to each other, so that light is emitted from a structure similar to
a rod-shaped light source such as CCFL by using point source of
light such as LED.
[0017] In the light source device according to the embodiment of
the invention, the arrangement restriction structure restricts
arrangement of a plurality of light source units, so that the
plurality of light source units are arranged in cascade. The
plurality of light source units are electrically connected to one
another via the respective electrical connection portions. Thus,
light is emitted from a structure similar to a rod-shaped light
source such as CCFL by using point source of light such as LED.
[0018] In the display apparatus according to the embodiment of the
invention, the plurality of light source units are arranged in
cascade within the optically transparent, cylindrical tube in each
of the plurality of rod-shaped light sources configuring the
illumination device. In each rod-shaped light source, adjacent
light source units are electrically connected to each other. Thus,
light is emitted from a structure similar to a rod-shaped light
source such as CCFL by using point source of light such as LED,
leading to image display similar to image display given by a
display apparatus using a rod-shaped light source such as CCFL as a
backlight.
[0019] According to the light source unit of the embodiment of the
invention, the light source unit is configured such that when a
plurality of light source units are arranged in cascade, the light
source element in the light source unit comes to in electric
connection with another light source element in an adjacent light
source unit. Therefore a structure similar to a rod-shaped light
source such as CCFL is achieved by using point source of light such
as LED.
[0020] According to the light source device of the embodiment of
the invention, the light source device is configured such that the
arrangement restriction structure restricts arrangement of a
plurality of light source units, so that the plurality of light
source units are arranged in cascade. In addition, the plurality of
light source units are electrically connected to one another via
the respective electrical connection portions. Therefore a
structure similar to a rod-shaped light source such as CCFL is
achieved by using point source of light such as LED.
[0021] According to the display apparatus of the embodiment of the
invention, the display apparatus is configured such that a
plurality of rod-shaped light sources are provided as an
illumination device, and a plurality of light source units are
arranged in cascade, and adjacent light source units are
electrically connected to each other within an optically
transparent, cylindrical tube in each of the rod-shaped light
sources. Therefore light is emitted from a structure similar to a
rod-shaped light source such as CCFL by using point source of light
such as LED, which enables image display similar to image display
given by a display apparatus using a rod-shaped light source such
as CCFL as a backlight.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a configuration view illustrating an example of a
light source device according to a first embodiment of the
invention.
[0023] FIGS. 2A to 2D are views illustrating a configuration
example of a light source unit formed by packaging the light source
element according to the first embodiment of the invention, and
illustrating a packaging process of the light source element.
[0024] FIG. 3 is an explanatory view illustrating a dimensional
relationship between the light source unit according to the first
embodiment of the invention and an outer tube to be inserted with
the light source unit.
[0025] FIG. 4 is a configuration view illustrating an example of
the outer tube to be inserted with the light source unit according
to the first embodiment of the invention.
[0026] FIG. 5 is an explanatory view illustrating a state where the
light source unit according to the first embodiment of the
invention is inserted into the outer tube.
[0027] FIG. 6 is a section view illustrating a configuration
example of a rod-shaped light source as a light source device
according to the first embodiment of the invention.
[0028] FIG. 7 is a circuit diagram illustrating an electrical
equivalent circuit of the rod-shaped light source as the light
source device according to the first embodiment of the
invention.
[0029] FIG. 8 is an explanatory view illustrating a light emission
principle of the rod-shaped light source as the light source device
according to the first embodiment of the invention.
[0030] FIG. 9 is a general configuration view illustrating an
example of a display apparatus using the light source device
according to the first embodiment of the invention.
[0031] FIGS. 10A to 10B are configuration views illustrating an
example of the light source device according to the first
embodiment of the invention.
[0032] FIGS. 11A to 11D are views illustrating a configuration
example of a non-light-emitting unit used in combination with a
light source unit according to a second embodiment of the
invention, and illustrating a packaging process of the
non-light-emitting unit.
[0033] FIG. 12 is an explanatory view illustrating a state where
the light source unit and the non-light-emitting unit according to
the second embodiment of the invention are inserted into a glass
tube (outer tube).
[0034] FIG. 13 is an explanatory view illustrating a dimensional
relationship between each of the light source units and the
non-light-emitting unit according to the second embodiment of the
invention, and the glass tube (outer tube).
[0035] FIG. 14 is a circuit diagram illustrating an electrical
equivalent circuit of a rod-shaped light source as a light source
device according to the second embodiment of the invention.
[0036] FIG. 15 is a view illustrating a configuration example of a
non-light-emitting unit used in combination with a light source
unit according to a third embodiment of the invention, and
illustrating a packaging process of the non-light-emitting
unit.
[0037] FIG. 16 is a section view illustrating a configuration
example of the non-light-emitting unit used in combination with the
light source unit according to the third embodiment of the
invention.
[0038] FIG. 17 is an explanatory view illustrating a state where a
light source unit and a non-light-emitting unit according to a
fourth embodiment of the invention are inserted into a glass tube
(outer tube).
[0039] FIG. 18 is an explanatory view illustrating a dimensional
relationship between each of the light source units and the
non-light-emitting unit according to the fourth embodiment of the
invention, and the glass tube (outer tube).
[0040] FIG. 19 is a structural view illustrating an example of a
contact structure of the non-light-emitting unit according to the
fourth embodiment of the invention.
[0041] FIG. 20 is a circuit diagram illustrating an electrical
equivalent circuit of a rod-shaped light source as a light source
device according to the fourth embodiment of the invention.
[0042] FIG. 21 is a configuration view illustrating an example of a
light source unit according to a fifth embodiment of the
invention.
[0043] FIG. 22 is an explanatory view illustrating a difficulty in
case that the light source unit according to the fifth embodiment
of the invention is not used.
[0044] FIG. 23 is an explanatory view illustrating an advantage of
using the light source unit according to the fifth embodiment of
the invention.
[0045] FIG. 24 is a view illustrating a configuration example of a
rod-shaped light source as a light source device according to a
sixth embodiment of the invention.
[0046] FIG. 25 is a configuration view illustrating an example of
an arrangement restriction structure in a light source device
according to a seventh embodiment of the invention.
[0047] FIG. 26 is a configuration view illustrating an example of a
light source device according to the seventh embodiment of the
invention.
[0048] FIG. 27 is a configuration view illustrating another example
of the light source device according to the seventh embodiment of
the invention.
[0049] FIG. 28 is an explanatory view of a backlight that partially
emits light.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0050] Hereinafter, preferred embodiments of the invention will be
described in detail with reference to drawings.
First Embodiment
[0051] FIG. 1 illustrates a structure of a light source element 11
according to a first embodiment of the invention.
[0052] The light source element 11 includes a generally plate-like
support substrate 1 having a rectangular surface, and an LED chip 2
disposed in the center of the support substrate 1. The support
substrate 1 and the LED chip 2 are formed using, for example, zinc
oxide as a main material and thus formed to be optically
transparent. The LED chip 2 emits, for example, ultraviolet light.
The zinc oxide may be added with MgO (magnesium oxide). Magnesium
oxide is added; thereby an emission wavelength may be
shortened.
[0053] In the embodiment, the light source element 11 corresponds
to one of examples of the "light source" in the invention, and the
LED chip 2 corresponds to one of examples of the "light emitting
element" in the invention.
[0054] Moreover, substrate electrodes 5 are provided on the surface
of the support substrate 1. Two substrate electrodes 5 are provided
for positive and negative electrodes on both ends in a longitudinal
direction. Two chip electrode-pads 3 for each of positive and
negative electrodes are provided on respective surfaces of the LED
chip 2 and the substrate electrodes 5. A chip electrode-pad 3 on
the LED chip 2 and a chip electrode-pad 3 on each substrate
electrode 5 are connected to each other by a wire 4, and thus
electrically conducted. Furthermore, a terminal electrode-pad 6 is
provided on the surface of each substrate electrode 5. The terminal
electrode-pad 6 is connected with one end of a terminal lead-line
7. In this way, the LED chip 2 is conducted to the terminal
lead-lines 7 at respective ends of the support substrate 1 via the
chip electrode-pads 3, wires 4, and the substrate electrodes 5.
[0055] The light source element 11 is used as a light source unit
in a multiply combined manner, and is structured such that when a
plurality of the light source elements are arranged in series or in
cascade as a light source unit, adjacent light source elements are
electrically connected in series or in cascade to each other.
[0056] FIG. 2D illustrates a configuration example of a light
source unit 25 for achieving such a structure. The light source
element 11 is enclosed (packaged) within the light source unit 25.
Hereinafter, the structure of the light source unit 25 is described
together with a packaging process of the light source element 11
with reference to FIGS. 2A to 2D. The light source unit 25 includes
a cylindrical glass tube 21 made of, for example, optically
transparent quartz (SiO.sub.2) glass, and a disk-like electrode
plate 22 provided at each of both ends of the glass tube 21. If
needed, the glass tube 21 may be made of a material opaque to
ultraviolet light, or may be subjected to coating treatment or the
like for filtering ultraviolet light as described later.
[0057] In the embodiment, the glass tube 21 corresponds to one of
examples of the "holding member" in the invention, and the
electrode plate 22 corresponds to one of examples of the
"connection electrode" in the invention.
[0058] As illustrated in FIG. 2A, the glass tube 21 has a hollowed
inside or a hollow space through which the light source element 11
is inserted. Length of the glass tube 21 and length of the support
substrate 1 of the light source element 11 are made approximately
the same, L1. In addition, an inner diameter of the glass tube 21
and width of the support substrate 1 of the light source element 11
are made approximately the same, d1. This gives a structure where
the support substrate 1 is held in the air by an inner
circumferential face of the glass tube 21 as illustrated in FIG.
2B.
[0059] The electrode plate 22 is optically transparent, for
example, by using zinc oxide as a main material. The electrode
plate 22 has a lead hole 23 to be inserted with the terminal
lead-line 7 of the light source element 11. In packaging, as
illustrated in FIGS. 2B and 2C, the light source element 11 is
inserted into the glass tube 21, and then the electrode plate 22 is
attached to each of both ends of the glass tube 21. At that time,
the terminal lead-line 7 is inserted through the lead hole 23 of
the electrode plate 22. Then, as illustrated in FIG. 2D, the
terminal lead-line 7 is folded at either end, and welded to a
welding portion 24 on an outer surface of the electrode plate 22.
This provides conduction to the inner light source element 11 via
the electrode plate 22, leading to a structure where in case that a
plurality of light source units 25 are arranged in cascade,
adjacent light source elements 11 are electrically connected in
series to each other via the electrode plate 22. In this way, in
the embodiment, the electrode plate 22 acts as an "electrical
connection portion" for electrically connecting a plurality of
light source units 25 to one another.
[0060] As illustrated in FIGS. 5 and 6, a plurality (n) of the
light source units 25 are combined in cascade, thereby the light
source units 25 are formed into a structure similar to a bar light
source or a rod-shaped light source such as CCFL as a light source
device. Next, description is made on a method of forming the
rod-shaped light source as the light source device by using the
light source units 25 in the embodiment.
[0061] FIGS. 3 and 4 illustrate an example of a hollow tube (outer
tube 31) used for configuring a rod-shaped light source
respectively. The outer tube 31 is a cylindrical glass tube made
of, for example, optically transparent quartz (SiO.sub.2) glass. If
needed, the outer tube 31 may be made by a material opaque to
ultraviolet light, or may be subjected to coating treatment or the
like for filtering ultraviolet light as described later. FIG. 3
illustrates a dimensional relationship between the outer tube 31
and the glass tube 21 of the light source unit 25. When it is
assumed that the glass tube 21 of the light source unit 25 has
inner diameter d1, outer diameter d2, and length L1, and the outer
tube 31 has inner diameter d3, outer diameter d4, and length L2,
the following dimensional relationship is given, enabling a
plurality of light source units 25 to be inserted into the outer
tube 31. The outer diameter d4 of the outer tube 31 is preferably
set to be, for example, about 3 mm to 7 mm.
d1<d2<d3<d4
L1<L2
[0062] An inner surface of the outer tube 31 is coated with a
phosphor 41 as illustrated in FIG. 4, and formed to be a
fluorescent surface that is excited by light from the light source
unit 25 and thereby emits fluorescent light.
[0063] A plurality of light source units 25 are inserted in cascade
into such an outer tube 31 as illustrated in FIG. 5. Thus, adjacent
light source units 25 are connected in cascade to each other via
the electrode plate 22 at both ends of the light source unit 25.
Consequently the rod-shaped light source is formed as illustrated
in FIG. 6. In this way, in the embodiment, the outer tube 31
restricts arrangement of the plurality of light source units 25,
and acts as an "arrangement restriction mechanism" or an
"arrangement restriction structure" for arranging the plurality of
light source units 25 in cascade. In the rod-shaped light source,
an external electrode body 60 is provided at each end 64 of an
outer tube 31. The external electrode body 60 includes an external
electrode 61 using, for example, iron (Fe) or nickel (Ni) as a main
material, and a crimp spring 62 attached in the inside of the
external electrode 61. The crimp spring 62 has a sufficient spring
property for exhibiting pressing force to keep contact between
respective electrode plates 22 of adjacent light source units 25.
The crimp spring 62 applies pressing force 63 to the inside, so
that a contact between the light source units 25 is stabilized.
[0064] FIG. 7 illustrates an electrical equivalent circuit of the
rod-shaped light source. FIG. 7 illustrates an example that the
rod-shaped light source emits light according to PWM (Pulse Width
Modulation) control. In the example, the rod-shaped light source is
connected with a power supply 73 at one end, and has a PWM switch
71 at the other end. The PWM switch 71 is controlled by a PWM
signal 72, so that light emission control is performed.
[0065] In case of forming a white rod-shaped light source, as
illustrated in FIG. 8, for example, a light source emitting
ultraviolet light 81 may be used as the light source element 11 of
the light source unit 25, and a phosphor that is excited by the
ultraviolet light 81 and thereby emits white luminescent light may
be used as the phosphor 41 on the inner surface of the outer tube
31. In this case, preferably, the glass tube 21 of the light source
unit 25 transmits light in a range from ultraviolet light to
visible light, and the outer tube 31 transmits visible light 82,
and does not transmit the ultraviolet light 81. This provides a
structure where harmful ultraviolet light 81 is cut off, and only a
fluorescent light emission component (white light) is emitted to
the outside as illumination light. While not illustrated, for
example, a phosphor may be provided on an inner surface of the
glass tube 21 configuring the light source unit 25. In this case,
the following configuration may be used: the glass tube 21
transmits the visible light 82, and does not transmit the
ultraviolet light 81.
[0066] In terms of light emitting efficiency, a light source
element, using zinc oxide as a main material to be shifted to a
relatively short wavelength, is preferably used as the light source
element 11. However, in case that the light source element being
shifted to a relatively short wavelength is used as a light
emitting material, ozone may be considered to be generated in
compensation for light emitting efficiency. In such a case, the
light source element 11 is preferably placed in a vacuum for
suppressing ozone generation. For example, the inside of the light
source unit 25 is preferably sealed in a vacuum.
[0067] Even if the inner surface of the outer tube 31 or the inner
surface of the light source unit 25 is not formed to be a
fluorescent surface, and white LED is used as the light source
element 11 of the light source unit 25, a white light source is
formed. Furthermore, the light source device according to the
embodiment is not limitedly used for the white light source, and
may be used for an ultraviolet lamp. Even in case that the light
source device is used as the ultraviolet lamp, the inner surface of
the outer tube 31 or the inner surface of the light source unit 25
is not formed to be a fluorescent surface.
[0068] FIG. 9 illustrates an example of a display apparatus using
the light source device (rod-shaped light source) according to the
embodiment. The display apparatus is a transmissive liquid crystal
display apparatus, and includes a liquid crystal panel 200, a
backlight 201, and a diffuser plate 202 disposed between the
backlight 201 and the liquid crystal panel 200. The backlight 201
corresponds to an illumination device, and uses the rod-shaped
light source in the embodiment. The liquid crystal panel 200
corresponds to a display section that displays an image by using
illumination light from the backlight 201 as light for display.
[0069] FIG. 10B illustrates a configuration example of the
backlight 201. FIG. 10A illustrates a state where the backlight 201
illustrated in FIG. 10B is disassembled. The backlight 201 includes
a light source group 102 including a plurality of rod-shaped light
sources, and a lamp house 101 as a housing for accommodating the
light source group 102. The rod-shaped light source of the
embodiment is used as each of the rod-shaped light sources of the
light source group 102. The light source group 102 is accommodated
within the lamp house 101 while being supported by as lamp holder
103 at each of both ends.
[0070] In the display apparatus, illumination light from the
backlight 201 is illuminated from a back side of the liquid crystal
panel 200 via the diffuser plate 202. In the liquid crystal panel
200, the illumination light is modulated according to an image
signal so that an image is displayed.
[0071] As described hereinbefore, according to the light source
unit 25 and the light source device of the embodiment, the light
source unit 25 and the light source device are configured such that
when a plurality of the light source units 25 are arranged in
cascade, the light source element 11 in the light source unit 25
comes to in electric connection with another light source element
11 in an adjacent light source unit 25, Therefore, a structure
similar to a rod-shaped light source such as CCFL is achieved.
Moreover, according to the display apparatus of the embodiment,
since a plurality of rod-shaped light sources are provided as an
illumination device, and the light source device of the embodiment
is used as the rod-shaped light source, image display is performed,
which is similar to image display of a previous display apparatus
using a rod-shaped light source such as CCFL as a backlight.
[0072] Particularly, according to the light source unit 25 of the
embodiment, since the light source unit has an electrical
connection portion (the electrode plate 22) at each of both ends
for electrically connecting a plurality of light source units 25 to
one another, the plurality of light source units 25 are easily
connected to one another. Thus, a plurality of light source
elements 11 are simply electrically connected in series to one
another without using a special tool.
[0073] In the case of an existent LED backlight system, since the
system is structured such that a plurality of LED light source
elements are directly mounted on an opaque substrate, each light
source element emits light only in one direction, i.e., a surface
direction of the mounting substrate. Therefore, loss is large in
terms of light emitting efficiency. On the other hand, according to
the light source device of the embodiment, since the light source
element 11 as a whole is enclosed in a transparent tube, light is
emitted even in an opposite direction (a back direction of the
mounting substrate) compared with a case of the existent LED
backlight system. Therefore, according to the light source device
of the embodiment, when the light source device is applied to a
device or the like requiring only one direction as an illumination
direction such as a backlight of a display apparatus, a reflective
plate may be provided on a surface opposite to a surface at an
illumination object, thereby radiation loss of light is suppressed
compared with the existent LED backlight system, consequently
amount of apparent light emission is increased. In addition, in
case that the light source device of the embodiment is used as the
backlight, since the light source device is configured such that a
plurality of rod-shaped light sources, each having the same
appearance as that of CCFL, are separately arranged in parallel,
the device has a significant advantage not only in terms of light
emitting efficiency but also in terms of heat radiation efficiency
compared with the existent LED backlight system. The existent LED
backlight system is structured such that a plurality of LED light
source elements are directly mounted on a plate-like substrate,
which is disadvantageous in terms of heat radiation.
Second Embodiment
[0074] Next, a second embodiment of the invention is described.
Substantially the same components as in the first embodiment are
denoted by the same symbols, and description of them is
appropriately omitted.
[0075] In the embodiment, a rod-shaped light source uses a
non-light-emitting unit 28 emitting no light (FIGS. 11A to 11D) in
addition to the light source unit 25. The non-light-emitting unit
28 may be used for adjusting an interval between the respective
light source units 25 within the outer tube 31. The
non-light-emitting unit 28 is approximately the same in external
structure as the light source unit 25, but the light source element
11 is not enclosed therein. The non-light-emitting unit 28 includes
a cylindrical glass tube 27 made of for example, optically
transparent quartz glass, and a disk-like electrode plate 22
provided at each of both ends of the glass tube 27, as in the light
source unit 25.
[0076] As illustrated in FIG. 11A, the glass tube 27 has a hollowed
inside or a hollow space. Length L3 of the glass tube 27 is
optionally set. Inner diameter d1 and outer diameter d2 of the
glass tube 27 are the same as those of the glass tube 21 of the
light source unit 25 respectively. The electrode plate 22 is the
same as the electrode plate 22 of the light source unit 25, and has
a lead hole 23. In the light source unit 25, as illustrated in
FIGS. 2B and 2C, the lead hole 23 is inserted with the terminal
lead-line 7 of the light source element 11 in packaging. However,
in the non-light-emitting unit 28, as illustrated in FIGS. 11B and
11C, the lead hole 23 is inserted with a connection lead-line 8.
Then, as illustrated in FIG. 11D, the connection lead-line 8 is
folded at each of both ends, and welded to a welding portion 24 on
an outer surface of the electrode plate 22. Thus, the electrode
plates 22 at both ends are electrically conducted to each other via
the connection lead-line 8.
[0077] One or more (m) non-light-emitting units 28 and a plurality
(n) of light source units 25 are combined in cascade as illustrated
in FIGS. 12 and 13, thereby a structure similar to a rod-shaped
light source such as CCFL is formed as a light source device. In
this case, the non-light-emitting units 28 for interval adjustment
are arranged in cascade with the light source units 25, and
adjacent light source units 25 are electrically connected in series
to each other partially via the non-light-emitting unit 28 (a
plurality of light source units 25 are separately arranged with the
non-light-emitting unit 28 being partially interposed between them)
within the outer tube 31. In this way, the rod-shaped light source
is the same in basic structure as in the first embodiment except
that the non-light-emitting unit 28 is partially used.
[0078] FIG. 14 illustrates an electrical equivalent circuit of the
rod-shaped light source of the embodiment. FIG. 14 illustrates an
example that the rod-shaped light source emits light according to
PWM control as in the first embodiment (FIG. 7). The circuit
configuration is the same as in the first embodiment except that a
portion corresponding to the non-light-emitting unit 28 is
expressed as a conductor line.
Third Embodiment
[0079] Next, a third embodiment of the invention is described.
Substantially the same components as in the above embodiments are
denoted by the same symbols, and description of them is
appropriately omitted.
[0080] In the embodiment, a rod-shaped light source uses a
non-light-emitting unit 50 emitting no light (FIGS. 15 to 16) in
addition to the light source unit 25 as in the second embodiment.
The non-light-emitting unit 50 may be used for adjusting an
interval between the respective light source units 25 within the
outer tube 31 as in the non-light-emitting unit 28 of the second
embodiment. The non-light-emitting unit 50 is approximately the
same in overall structure as the light source unit 25, but the
light source element 11 is not enclosed therein. The
non-light-emitting unit 50 includes a cylindrical glass tube 57
made of, for example, optically transparent quartz glass, and an
electrode cap 52 provided at each of both ends of the glass tube 57
similarly as the light source unit 25.
[0081] The glass tube 57 is covered with an optically transparent,
transparent conductive film (such as ITO) 58 over an outer surface
thereof. In a case that a light source element emitting ultraviolet
light is used as the light source element 11, the transparent
conductive film 58 is preferably made of a material being
transparent not only to visible light but also ultraviolet light.
The electrode cap 52 is adhered to each of both ends of the glass
tube 57 by a conductive adhesive 53. The electrode cap 52 has an
air hole 51. For the electrode cap 52, light-reflective metal
(aluminum) or the like is used. However, a transparent electrode
cap 52 may be formed by using ITO-coated glass or the like. In this
way, the non-light-emitting unit 50 has a structure where the
entire surface is covered with a material being electrically
conductive.
[0082] One or more (m) non-light-emitting units 50 and a plurality
(n) of light source units 25 are combined in cascade as in the
second embodiment, thereby a structure similar to a rod-shaped
light source such as CCFL is formed as a light source device. In
this case, the non-light-emitting units 50 for interval adjustment
are arranged in cascade with the light source units 25, and
adjacent light source units 25 are electrically connected in series
to each other partially via the non-light-emitting unit 50 within
the outer tube 31. The rod-shaped light source in the embodiment is
the same in basic structure as in the first embodiment except that
the non-light-emitting unit 50 is partially used.
Fourth Embodiment
[0083] Next, a fourth embodiment of the invention is described.
Substantially the same components as in the above embodiments are
denoted by the same symbols, and description of them is
appropriately omitted.
[0084] In the embodiment, the non-light-emitting unit 50 in the
third embodiment is used as an electrical contact for lead-out to
the outside. FIGS. 17 and 18 illustrate a configuration example of
a rod-shaped light source according to the embodiment respectively.
The rod-shaped light source of the embodiment has a cut-hole-formed
outer tube 42 partially having a cut hole 43 in place of the outer
tube 31 in the first embodiment. The non-light-emitting unit 50 and
the light source unit 25 are accommodated within the
cut-hole-formed outer tube 42. The non-light-emitting unit 50 is
disposed at a position corresponding to the cut hole 43. Thereby,
an electrical contact to the outside is formed at the
non-light-emitting unit 50. Size of the cut hole 43 is formed small
compared with size of each of the non-light-emitting unit 50 and
the light source unit 25 so that each of the non-light-emitting
unit 50 and the light source unit 25 does not fall off from the
inside of the outer tube 42 to the outside.
[0085] The electrical contact to the outside may be achieved by,
for example, a clamp mechanism or a clamp structure as illustrated
in FIG. 19. In the clamp structure, a holder (clamp) 59 is used to
hold the non-light-emitting unit 50 from the outside of the outer
tube 42 via the cut hole 43. The holder 59 is made conductive.
Thereby, electrical conduct from the outside of the outer tube 42
is made via the holder 59.
[0086] FIG. 20 illustrates an electrical equivalent circuit of the
rod-shaped light source of the embodiment. FIG. 20 illustrates an
example that the rod-shaped light source emits light according to
PWM control as in the first embodiment (FIG. 7). The circuit
configuration is basically the same as in the first embodiment
except that a portion corresponding to the non-light-emitting unit
50 is expressed as a conductor line. However, an optional
non-light-emitting unit 50 is made as the electrical contact to the
outside.
[0087] When the light source unit 25 is assumed as one light
source, the rod-shaped light source as a light source device of the
embodiment may be considered to be an assembly of a plurality of
single light sources. In addition, the above electrical contact is
provided. Thereby a light source unit 25 in any region is turned
one Therefore, the light source device of the embodiment may be
used for a partial-driving LED backlight.
[0088] FIG. 28 illustrates a concept of the partial-driving LED
backlight. In the backlight 110, a light-emitting area of the
entire screen is divided into a plurality of partial light-emitting
areas 111 of n in row and m in column, and light emission control
is independently made for each partial light-emitting area 111. In
a display apparatus using the partial-driving LED backlight, since
luminance of a backlight is partially changed depending on an image
to be displayed, an image having relatively high quality is
displayed. By using the light source device of the embodiment,
since partial light emission is made even in a rod-shaped light
source, it is possible to establish such a partial-driving LED
backlight.
Fifth Embodiment
[0089] Next, a fifth embodiment of the invention is described.
Substantially the same components as in the above embodiments are
denoted by the same symbols, and description of them is
appropriately omitted.
[0090] FIG. 21 illustrates an example of a light source unit 25A
according to the embodiment.
[0091] In the embodiment, a prevention structure is provided at
each of both ends (electrode plate 22) of the light source unit 25A
for preventing displacement between adjacent light source units. A
convex portion 32 and a concave portion 33 are provided as the
prevention structure in the electrode plate 22 at each of both
ends. In a case that the electrode plate 22 at each of both ends is
flat, when a plurality of light source units 25A are combined,
since each glass tube is freely rotated as illustrated in FIG. 22,
a mutual position between the electrode plates 22 is not fixed. On
the other hand, in the embodiment, the structure as illustrated in
FIG. 21 is made, thereby when a plurality of light source units 25A
are combined, since the convex portion 32 and the concave portion
33 are engaged with each other between adjacent light source units
25A, the displacement is prevented.
[0092] In a case that the light source unit 25A of the embodiment
is to be inserted into an outer tube 31, a step is performed where
a wire-like lead line 9 is beforehand inserted through a lead hole
23 of the electrode plate 22 as illustrated in FIG. 23, and the
lead line 9 is pulled out later. Thereby, the convex portion 32 and
the concave portion 33 between the light source units 25A are
engaged with each other in the outer tube 31 so that the
displacement is securely prevented, and consequently the light
source unit is easily processed and assembled. In this case, the
lead line 9 preferably includes a material having high hardness so
as to provide high bending resistance. This reduces a stroke to the
utmost, the stroke being a rotation stroke of the light source unit
25A in a tube diameter direction within the outer tube 31.
Therefore, the light source unit 25A is positioned with respect to
a different light source unit 25A, being previously accommodated in
the outer tube 31, concurrent with insertion of a light source unit
25A into the outer tube 31.
[0093] In a case that a plurality of light source units 25A are to
be accommodated in the outer tube 31, before a light source unit
25A is accommodated, an electrode plate 22 at each of both ends of
the light source unit may be beforehand engaged with an electrode
plate 22 at each of both ends of a different light source unit, and
the light source units 25A may be accommodated step by step. This
also enables secure electrical connection between a plurality of
light source units 25A within the outer tube 31.
Sixth Embodiment
[0094] Next, a sixth embodiment of the invention is described.
Substantially the same components as in the above embodiments are
denoted by the same symbols, and description of them is
appropriately omitted.
[0095] FIG. 24 illustrates a configuration example of a rod-shaped
light source according to the embodiment.
[0096] In the embodiment, a light source element 11 itself is used
as a light source unit. In the embodiment, a groove 300 is provided
on an inner surface of the outer tube 31, and a light source
element 11 is inserted into the outer tube in such a manner that a
support substrate 1 is sandwiched in the groove 300. In the
embodiment, respective ends of adjacent light source elements 11
are directly conducted to each other via a terminal lead-line 7
within the outer tube 31.
Seventh Embodiment
[0097] Next, a seventh embodiment of the invention is described.
Substantially the same components as in the above embodiments are
denoted by the same symbols, and description of them is
appropriately omitted.
[0098] In the above embodiments, the cylindrical tube is used for
an arrangement restriction structure for arranging the light source
units in cascade. However, in the embodiment, rail-shaped guide
members 90A and 90B are used for the arrangement restriction
structure as illustrated in FIG. 25, In addition, the embodiment
uses a light source element 11A itself as a light source unit. Two
guide members 90A and 90B are arranged in parallel. Grooves 92 are
provided on at least opposed inside portions of the two guide
members 90A and 90B arranged in parallel respectively.
[0099] FIG. 26 illustrates a configuration example where a
plurality of light source elements 11A are arranged in cascade by
using the guide members 90A and 90B. In the embodiment, two guide
members 90A and 90B are arranged in parallel, and a plurality of
light source elements 11A are accommodated in such a manner that
each of both ends of a light source element 11A is slid into the
groove 92. An arrangement interval (interval in a Y direction in
the figure) between the two guide members 90A and 90B arranged in
parallel is set small compared with a size of the light source
element 11A, so that each of both ends of a light source element
11A may be held between the guide members. In (a support substrate
1 of) each light source element 11A, an electrical connection
portion 12 is formed for connecting an LED chip 2 to the outside or
to a different light source element 11A at each of both ends in a
direction (Y direction in the figure) perpendicular to an
arrangement direction (X direction in the figure) of a plurality of
light source elements 11A. Moreover, a current path to be connected
to the electrical connection portion 12 is formed in the groove 92
of each of the guide members 90A and 90B. Thus, when a plurality of
light source elements 11A are accommodated into the guide members
90A and 903, the light source elements are electrically connected
to one another via electrical connection portions 12 at both ends
of respective elements and respective current paths of the guide
members 90A and 90B.
[0100] In the configuration example of FIG. 26, since the plurality
of light source elements 11A are electrically connected to one
another via the respective current paths formed in the guide
members 90A and 90B, adjacent light source elements 11A are not
necessary to be directly contacted to each other, and an optional
interval D may be provided between the plurality of light source
elements 11A. Therefore, a non-light-emitting element or the like
is also unnecessary to be provided for adjusting an interval. In
the configuration example of FIG. 26, the interval D is provided
between all of the light source elements 11A. However, the light
source elements may be arranged such that a part or all of the
light source elements 11A are contacted to one another, that is,
the interval D is zero.
[0101] In the configuration example of FIG. 26, in a case that the
respective current paths formed in the guide members 90A and 90B
act as common electrodes of the respective electrical connection
portions 12 of the plurality of light source elements 11A, the
plurality of light source elements 11A have a parallel
electrical-connection relationship in an X direction in the figure.
The case that the current paths act as the common electrodes
described herein means, for example, a case of a configuration
where a current path is continuously formed in the groove 92 of
each of the guide members 90A and 90B, and a current path in one
guide member 90A is used to commonly connect between electrical
connection portions 12 at respective one ends of the plurality of
light source elements 11A, and a current path in the other guide
member 90B is used to commonly connect between electrical
connection portions 12 at respective other ends of the plurality of
light source elements 11A.
[0102] On the other hand, in the configuration example of FIG. 26,
the plurality of light source elements 11A may also be made to have
a series electrical-connection relationship. For example, a pattern
may be formed as a current path formed in each of the guide members
90A and 90B, in which a conductive region and an insulative region
alternately appear in correspondence to an arrangement interval
between the plurality of light source elements 11A. In this case,
when it is assumed that a current sequentially flows through the
plurality of light source elements 11A from a near side to a back
side in the X direction in FIG. 26, a direction (polarity) of the
current is alternately changed in a Y direction within each light
source element HA (current directions in the Y direction is opposed
to each other between adjacent light source elements 11A),
consequently the current flows in a zigzag.
[0103] FIG. 27 illustrates another configuration example of a light
source device of the embodiment. In this configuration example, in
(a support substrate 1 of) each light source element 11B, an
electrical connection portion 13 is formed at each of both ends in
the same direction (X direction in the figure) as an arrangement
direction of a plurality of light source elements 11B for
connecting the plurality of light source elements to one another.
The light source elements are fixedly held by grooves 92 and outer
side faces 91 of respective guide members 90A and 90B therebetween.
In the configuration example, when the plurality of light source
elements 11B are accommodated between the guide members 90A and
90B, adjacent electrical connection portions 13 contact to each
other, thereby the plurality of light source elements 11B are
electrically connected to one another. The electrical connection
portion 13 of the light source element 11B may have a
concavo-convex shape such that adjacent electrical connection
portions are engaged with each other in order to secure mechanical
connection strength and ease in connection. More specifically, the
light source device may be configured in such a manner that an
electrical connection portion 13 at one end of the light source
element 11B is made to have a male pattern (convex shape), and an
electrical connection portion 13 at the other end thereof is made
to have a female pattern (concave shape), so that when a plurality
of light source elements 11B are arranged, adjacent light source
elements are engaged with each other by the respective e electrical
connection portions 13.
[0104] As in the configuration example of FIG. 26, a current path
may be formed in each of the guide members 90A and 90B even in the
configuration example of FIG. 27. However, since a plurality of
light source elements 11B are directly connected to one another by
the electrical connection portions 13 of the light source elements
11B in the configuration example of FIG. 27, such a current path
may not be necessarily provided. In addition, in the configuration
example of FIG. 27, the optional interval D is not provided between
the light source elements 11B unlike the configuration example of
FIG. 26. Therefore, a non-light-emitting element 14 may be provided
for adjusting an interval as needed.
[0105] A backlight of a display apparatus may be configured even by
using the light source device of the embodiment. Moreover, a
partial-driving backlight may be configured by using the device as
in the fourth embodiment. For example, when an electrical contact
for lead-out to the outside is provided at an optional position in
a current path in each of the guide members 90A and 90B so that a
light source element 11B at the optional position partially emits
light, it is possible to establish the partial-driving
backlight.
Other Embodiment
[0106] The invention is not limited to the above embodiments, and
various other modifications may be made.
[0107] For example, while an example of a liquid crystal display
apparatus (FIG. 9) is described as a display apparatus in the first
embodiment, the light source device of the invention may be used
for various display apparatuses other than the liquid crystal
display apparatus. Moreover, the light source device of the
invention may be used for various applications other than a
backlight of a display apparatus.
[0108] It should be understood by those skilled in the art that
various modifications, combinations, sub-combinations and
alterations may occur depending on design requirements and other
factors insofar as they are within the scope of the appended claims
or the equivalent thereof.
* * * * *