U.S. patent application number 16/899129 was filed with the patent office on 2020-09-24 for projection lens and projector.
This patent application is currently assigned to FUJIFILM Corporation. The applicant listed for this patent is FUJIFILM Corporation. Invention is credited to Yasuto KURODA.
Application Number | 20200301267 16/899129 |
Document ID | / |
Family ID | 1000004885585 |
Filed Date | 2020-09-24 |
United States Patent
Application |
20200301267 |
Kind Code |
A1 |
KURODA; Yasuto |
September 24, 2020 |
PROJECTION LENS AND PROJECTOR
Abstract
A first holding member holds a first optical system and a first
mirror, and has a first junction surface. A second holding member
holds a second optical system and a second mirror, and has a second
junction surface. A junction portion is configured such that, in a
state where the first junction surface and the second junction
surface are aligned with each other, the second holding member is
capable of being shifted in a direction of both the junction
surfaces and rotated around an optical axis, and makes it possible
to perform optical axis alignment. An emission-side optical axis of
the first optical system and an incidence-side optical axis of the
second optical system are aligned with each other, and thus a
U-shaped optical path is formed by the first and second optical
systems.
Inventors: |
KURODA; Yasuto;
(Saitama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJIFILM Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
FUJIFILM Corporation
Tokyo
JP
|
Family ID: |
1000004885585 |
Appl. No.: |
16/899129 |
Filed: |
June 11, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16660453 |
Oct 22, 2019 |
10719003 |
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16899129 |
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16193979 |
Nov 16, 2018 |
10488747 |
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16660453 |
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15938093 |
Mar 28, 2018 |
10168609 |
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16193979 |
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PCT/JP2016/076639 |
Sep 9, 2016 |
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15938093 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03B 21/28 20130101;
G03B 21/14 20130101; G02B 7/02 20130101; G03B 21/00 20130101; G02B
7/021 20130101; G03B 21/147 20130101; G02B 27/0955 20130101; G02B
13/16 20130101 |
International
Class: |
G03B 21/28 20060101
G03B021/28; G02B 7/02 20060101 G02B007/02; G02B 13/16 20060101
G02B013/16; G03B 21/00 20060101 G03B021/00; G03B 21/14 20060101
G03B021/14; G02B 27/09 20060101 G02B027/09 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2015 |
JP |
2015-192002 |
Claims
1. A projector comprising: a projector body; an image forming
panel; a lens mount on which a first projection lens including an
optical axis bending member or a second projection lens is
selectively mounted; and an optical member between the lens mount
and the image forming panel in an optical path, wherein a
projection distance or a projection angle of the first projection
lens is different from a projection distance or a projection angle
of the second projection lens, and wherein the first projection
lens and the second projection lens project a projected image using
the optical member and the image forming panel commonly.
2. The projector according to claim 1, wherein the first projection
lens and the second projection lens are shiftable with respect to
the projector body at least in a vertical direction, so that the
projector can change a projection position of the projected image
in a state where a position of the projector is fixed.
3. The projector according to claim 1, wherein the projection lens
is shiftable with respect to the projector body in a horizontal
direction.
4. The projector according to claim 1 further comprising: a first
frame that holds at least an incident lens; a second frame that
holds at least an emission lens; and a third frame that holds an
intermediate lens, wherein the first projection lens is a
combination of at least the second frame and the third frame.
5. The projector according to claim 4, wherein the optical member
is the incident lens of the first frame.
6. The projector according to claim 4 further comprising: a fourth
frame that holds the optical axis bending member, wherein the first
projection lens is a combination of at least the fourth frame, the
second frame, and the third frame.
7. The projector according to claim 4 further comprising: wherein
the optical axis bending member and the intermediate lens are
located outside of an edge of the projector body in a side view,
and wherein the incident lens and the emission lens are located
inside of the edge of the projector body in the side view.
8. The projector according to claim 7, wherein the incident lens is
located more inside of the edge than the emission lens in the side
view.
9. The projector according to claim 4 further comprising: a holding
member including the first frame and the lens mount, wherein the
first projection lens and the holding member composes a
substantially U-shaped optical path.
10. The projector according to claim 4 further comprising: a
holding member including another optical axis bending member, the
first frame and the lens mount.
11. The projector system comprising: the projector according to
claim 1; the first projection lens, and the second projection
lens.
12. The projector system comprising: the projector according to
claim 2; the first projection lens, and the second projection
lens.
13. The projector system comprising: the projector according to
claim 3; the first projection lens, and the second projection
lens.
14. The projector system comprising: the projector according to
claim 4; the first projection lens, and the second projection
lens.
15. The projector system comprising: the projector according to
claim 5; the first projection lens, and the second projection
lens.
16. The projector system comprising: the projector according to
claim 6; the first projection lens, and the second projection
lens.
17. The projector system comprising: the projector according to
claim 7; the first projection lens, and the second projection
lens.
18. The projector system comprising: the projector according to
claim 8; the first projection lens, and the second projection
lens.
19. The projector system comprising: the projector according to
claim 9; the first projection lens, and the second projection
lens.
20. The projector system comprising: the projector according to
claim 10; the first projection lens, and the second projection
lens.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of copending U.S. patent
application Ser. No. 16/660,453, filed Oct. 22, 2019, which is a
Continuation of U.S. patent application Ser. No. 16/193,979, filed
Nov. 16, 2018, which has patented as U.S. Pat. No. 10,488,747 on
Nov. 26, 2019, which is a Divisional of U.S. patent application
Ser. No. 15/938,093 filed Mar. 28, 2018, which has patented as U.S.
Pat. No. 10,168,609 on Jan. 1, 2019, which is a Continuation of PCT
International Application No. PCT/JP2016/076639 filed on Sep. 9,
2016, which claims priority under 35 U.S.C .sctn. 119(a) to
Japanese Patent Application No. 2015-192002 filed on Sep. 29, 2015.
The above applications are hereby expressly incorporated by
reference, in their entirety, into the present application.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to a projection lens and a
projector.
2. Description of the Related Art
[0003] In recent years, projectors having an image forming panel
such as a liquid crystal display device or a digital micromirror
device (DMD) mounted therein have been in widespread use and have
increased in performance. Particularly, with an improvement in the
resolution of the image forming panel, there has also been a demand
for an improvement in the resolution performance of a projection
optical system.
[0004] In addition, in consideration of improving the degree of
freedom of the setting of distance to a screen or installability in
an indoor space, there has been a strong demand for mounting a
projection optical system having high versatility, in which higher
performance and a wider angle are achieved with a compact
configuration, in a projector.
[0005] In order to respond to such a demand, a projection optical
system is proposed in which an intermediate image is formed in a
first optical system consisting of a plurality of lenses, and the
image is re-formed in a second optical system likewise consisting
of a plurality of lenses (see WO09/107553A (corresponding to US
2011/002034A1) and JP2006-330410A).
[0006] In a projection optical system composed of only an optical
system having no normal intermediate image formed thereon, in a
case where an attempt is made to widen an angle by reducing a focal
length, a lens on the magnified side becomes excessively large. On
the other hand, in a projection optical system of a type in which
intermediate imaging is performed, it is possible to shorten the
back focus of a second optical system, and to reduce the lens
diameter of the second optical system on the magnified side.
Therefore, the system is also suitable for widening an angle by
reducing a focal length.
[0007] As a projector having a mirror incorporated into a
projection optical system, a rear projector of which the optical
axis is bent is proposed (see JP2008-203540A (corresponding to US
2008/291552A1)). In this rear projector, when a projection lens
unit is assembled which consists of a convergence optical system, a
mirror, a magnification optical system, and a lens housing having
these components integrally incorporated thereinto, the position of
the mirror is adjusted and then the mirror is fixed with an
adhesive. Thereby, even in a case where a mirror holding portion of
the lens housing is not processed with a high degree of accuracy,
the mirror is accurately fixed.
SUMMARY OF THE INVENTION
[0008] However, WO09/107553A and JP2006-330410A have an adverse
effect that the entire lens length increases due to an intermediate
image being formed one time. For this reason, the projection
optical system as disclosed in WO09/107553A and JP2006-330410A are
not able to be used, as it is, in a projector having a requirement
for compactness.
[0009] In JP2008-203540A, compactness is achieved by disposing a
mirror between a convergence optical system and a magnification
optical system to bend an optical axis. However, a length in a
traverse direction, for example, is shortened as much as the
optical axis is bent simply by inserting one mirror, but a length
in a longitudinal direction is lengthened as much as the optical
axis is bent, which leads to no achievement in compactness in a
longitudinal direction. Further, since the optical axis and a
screen surface are not at right angles to each other, there is a
need for a mirror for bending a ray of light emitted from a front
lens element which is a distal end lens of the projection lens.
[0010] The present invention is contrived in view of such
circumstances, and an object thereof is to provide a projection
lens and a projector which are capable of being accurately
assembled while achieving a reduction in size, and are capable of
widening an angle by reducing a focal length.
[0011] In order to achieve the above object, according to the
present invention, there is provided a projection lens comprising a
first optical system, a first optical axis bending member, a second
optical system, a second optical axis bending member, a first
holding member, a second holding member, a first junction surface,
a second junction surface, and a junction portion. The first
optical axis bending member is disposed between the first optical
system and an image forming surface of the first optical system,
and bends an optical axis. The second optical system projects an
image formed by the first optical system onto a projection surface.
The second optical axis bending member is disposed in the second
optical system and bends an optical axis. The first holding member
integrally holds the first optical system and the first optical
axis bending member. The second holding member integrally holds the
second optical system and the second optical axis bending member.
The first junction surface intersects an emission-side optical axis
of the first optical system and is formed in the first holding
member. The second junction surface intersects an incidence-side
optical axis of the second optical system and is formed in the
second holding member. The junction portion is configured such
that, in a state where the first junction surface and the second
junction surface are aligned with each other, at least one of the
first holding member and the second holding member is capable of
being shifted in a direction of both the junction surfaces and
rotated around the optical axis with respect to the other holding
member. The junction portion is configured such that a U-shaped
optical path is formed by optical axis alignment between an
emission side of the first optical system and an incidence side of
the second optical system.
[0012] It is preferable that the junction portion includes a screw
hole, a mounting hole, and a mounting screw. The screw hole is
provided in one of the first holding member and the second holding
member. The mounting screw is provided in the other of the first
holding member and the second holding member. The mounting screw is
inserted from the mounting hole and screwed to the screw hole, and
fixes the first holding member and the second holding member in a
state where the first junction surface and the second junction
surface are closely attached to each other. The junction portion is
configured such that the first holding member and the second
holding member are relatively shifted in the direction of both the
junction surfaces and are rotated around the optical axis, within a
gap between the mounting hole and the mounting screw.
[0013] It is preferable that the junction portion includes an
intermediate member, a first mounting screw, and a second mounting
screw. The intermediate member is configured such that the first
holding member and the second holding member are relatively shifted
in the direction of both the junction surfaces and are rotated
around the optical axis, between the first junction surface and the
second junction surface. The first mounting screw fixes the
intermediate member to the first junction surface by performing one
of a shift and rotation around the optical axis between the first
junction surface and the intermediate member. The second mounting
screw fixes the intermediate member to the second junction surface
by performing the other of a shift and rotation around the optical
axis between the intermediate member and the second junction
surface.
[0014] It is preferable that the junction portion includes an
intermediate mount, and that the second holding member is
detachably mounted to the intermediate mount. The intermediate
mount is closely attached to the first junction surface, and has a
second junction surface.
[0015] According to the present invention, there is provided a
projector comprising an image forming panel that displays an image,
a light source that illuminates the image forming panel, and the
projection lens that projects illumination light, from the image
forming panel illuminated by the light source, onto a projection
surface.
[0016] In addition, according to the present invention, there is
provided a projector comprising a projector main body including an
image forming panel that displays an image and a light source that
illuminates the image forming panel, and the projection lens,
detachably mounted to the projector main body, which projects
illumination light from the image forming panel illuminated by the
light source.
[0017] It is preferable that the image forming panel is disposed
such that a center of the image forming panel is shifted with
respect to the optical axis of the first optical system. In
addition, it is preferable that the image forming panel is disposed
such that a center of the image forming panel is shifted with
respect to the optical axis of the first optical system in a
direction of the optical axis bent by the first optical axis
bending member.
[0018] According to the present invention, it is possible to
provide a projection lens and a projector which are capable of
being accurately assembled while achieving a reduction in size, and
are capable of widening an angle by reducing a focal length.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a longitudinal cross-sectional view illustrating a
projection lens of a first embodiment of the present invention.
[0020] FIG. 2 is a longitudinal cross-sectional view illustrating a
state where a second holding member is mounted to a first holding
member.
[0021] FIG. 3 is a cross-sectional view taken along line in FIG.
1.
[0022] FIG. 4 is a perspective view illustrating a projector having
a projection lens mounted to a projector main body.
[0023] FIG. 5 is a schematic diagram illustrating a comparison
between a projection screen and an installation state of a
projector of the present invention and a projector of related
art.
[0024] FIG. 6 is an exploded longitudinal cross-sectional view
illustrating the periphery of a junction portion of a projection
lens of a second embodiment using an intermediate member.
[0025] FIG. 7 is an exploded longitudinal cross-sectional view
illustrating the periphery of a junction portion of a projection
lens of a third embodiment using an intermediate mount.
[0026] FIG. 8 is a perspective view illustrating replacement
between a second holding member and a third holding member in the
third embodiment.
[0027] FIG. 9 is a transverse cross-sectional view illustrating the
periphery of a junction portion of a fourth embodiment using a fine
adjustment screw.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
[0028] As shown in FIG. 1, a projection lens 10 of the present
embodiment includes a first optical system 11, a second optical
system 12, a first mirror 13 as a first optical axis bending
member, a second mirror 14 as a second optical axis bending member,
a first holding member 15, a second holding member 16, a first
junction surface 17, a second junction surface 18, and a junction
portion 19.
[0029] The first optical system 11 is composed of a first lens 21
and a second lens 22. The first lens 21 and the second lens 22 are
displayed as a single lens for the purpose of simplifying the
illustration, but are actually composed of a plurality of lens
groups. The first optical system 11 forms an image of an image
forming panel 67, as an intermediate image, on an image forming
surface 23.
[0030] The first mirror 13 is disposed between the first optical
system 11 and the image forming surface 23 of the intermediate
image formed by the first optical system 11. The first mirror 13
reflects projection light by bending an optical axis CL1 of the
first optical system by 90.degree..
[0031] The first holding member 15 integrally holds the first
optical system 11 and the first mirror 13. The first holding member
15 includes a first main body 24, a mounting cylinder 25, a first
lens frame 26, and a second lens frame 27. The first main body 24
is constituted by a square cylinder having a substantially
rectangular shape. One corner of a lower plate 24a of the first
main body 24 is cut out obliquely, and an inclination portion 24b
is formed. The first mirror is fixed onto the inside surface of the
inclination portion 24b.
[0032] A first mounting hole 24d of the first optical system 11 is
formed in an entrance-side front plate 24c facing the inclination
portion 24b. The mounting cylinder 25, the first lens frame 26, and
the second lens frame 27 are mounted to this first mounting hole
24d by mounting screws 28 and 29. The respective mounting screws 28
and 29 are disposed, for example, at a pitch of 120.degree. on the
hole edge of the first mounting hole 24d in a circumferential
direction. In the present embodiment, another mounting screw
described later is similarly disposed, for example, at a pitch of
120.degree. on the hole edge in a circumferential direction. One or
more mounting screws may be used. In addition, both may be fixed to
each other using an adhesive, instead of the mounting screws 28 and
29 and the like, or in addition thereto. A second mounting hole 24f
is formed in an upper plate 24e of the first main body 24 of the
first holding member 15.
[0033] The second optical system 12 is composed of a third lens 35,
a fourth lens 36, a fifth lens 37, and a sixth lens 38. The fourth
lens 36 to the sixth lens 38 are displayed as a single lens for the
purpose of simplifying the illustration, but are actually composed
of a plurality of lens groups.
[0034] The second optical system 12 magnifies the intermediate
image formed on the image forming surface 23 by the first optical
system 11, and projects the magnified image onto, for example, a
screen 39 which is an object to be projected. Meanwhile, the first
optical system 11 and the second optical system 12 are described in
detail in "Optical System for Projection and Projection-type
Display Device" of, for example, JP2015-035085, JP2015-045989 and
the like, and optical systems disclosed therein can be used as the
first optical system 11 and the second optical system 12. According
to the optical system for projection and the projection-type
display device, an optical system is obtained which has high
projection performance and in which various aberrations are
satisfactorily corrected with a wide angle.
[0035] The second mirror 14 is disposed between the third lens 35
and the fourth lens 36 of the second optical system 12. The second
mirror 14 reflects projection light by bending an optical axis CL2
of the second optical system 12 by 90.degree..
[0036] The second holding member 16 integrally holds the second
optical system 12 and the second mirror 14. The second holding
member 16 includes a second main body 40, a mounting plate 41, a
third lens frame 42, a fourth lens frame 43, and a fifth lens frame
44. The second main body 40 is constituted by a square cylinder
having a substantially rectangular shape. One corner of an upper
plate 40a of the second main body 40 is cut out obliquely, and an
inclination portion 40b is formed. The second mirror 14 is fixed
onto the inside surface of the inclination portion 40b.
[0037] A third mounting hole 40d is formed on a lower plate 40c,
located on the lower side, which faces the inclination portion 40b
in a vertical direction. The emission-side end face of the third
lens frame 42 is inserted into this third mounting hole 40d from a
vertically downward direction. A flange 42a is formed on the
emission-side end face of the third lens frame 42. The flange 42a
and the lower plate 40c are fixed to each other by a mounting screw
46.
[0038] A flange 40e is extensively provided on a front end face
facing the inclination portion 40b in a horizontal direction. The
mounting plate 41 is fixed to this flange 40e by a mounting screw
47. The mounting plate 41 has a mounting hole 41a. The fifth lens
frame 44 that holds the sixth lens 38 is inserted into the mounting
hole 41a. The fifth lens frame 44 is fixed to the mounting plate 41
by a mounting screw 48. The fourth lens frame 43 is externally
fitted to the incidence-side end of the fifth lens frame 44 and is
movably mounted in the direction of an emission-side optical axis
CL2O of the second optical system 12.
[0039] As shown in FIG. 2, the first junction surface 17 is formed
on the upper plate 24e of the first holding member 15 so as to be
at right angles to an emission-side optical axis CL1O of the first
optical system 11. In addition, the second junction surface 18 is
formed on the flange 42a of the third lens frame 42 of the second
holding member 16 so as to be at right angles to an incidence-side
optical axis CL2I of the second optical system 12.
[0040] The first holding member 15 and the second holding member 16
are individually assembled. In a case where the assembly of the
first optical system 11 is completed, an incidence-side optical
axis CL1I of the first optical system 11 is bent by 90.degree.
following reflection from the first mirror 13, and serves as the
emission-side optical axis CL1O. In addition, the first junction
surface 17 is at right angles to the emission-side optical axis
CL1O of the first optical system 11. Similarly, in a case where the
assembly of the second optical system 12 is completed, the
incidence-side optical axis CL2I of the second optical system 12 is
bent by 90.degree. following reflection from the second mirror 14,
and serves as the emission-side optical axis CL2O. In addition, the
second junction surface 18 is at right angles to the incidence-side
optical axis CL2I of the second optical system 12. Meanwhile, the
first junction surface 17 is at right angles to the optical axis
CL1O, and the second junction surface 18 is at right angles to the
optical axis CL2I, but both the junction surfaces may intersect the
respective optical axes CL1O and CL2I at constant angles instead of
the right angles.
[0041] As shown in FIG. 1, the first holding member 15 and the
second holding member 16 are assembled by the junction portion 19
in a state where the first junction surface 17 and the second
junction surface 18 are closely attached to each other. The
junction portion 19 is configured such that, in a state where the
first junction surface 17 and the second junction surface 18 are
aligned with each other, at least one of the first holding member
15 and the second holding member 16 is shifted in the direction of
both the junction surfaces 17 and 18 and is rotatable around the
optical axis CL1O with respect to the other. Thereby, the
emission-side optical axis CL1O of the first optical system 11 and
the incidence-side optical axis CL2I of the second optical system
12 are aligned with each other. On the optical axes CL1O and CL2I
aligned with each other, a U-shaped optical path is formed by the
incidence-side optical axis CL1I of the first optical system 11 and
the emission-side optical axis CL2O of the second optical system
12.
[0042] As shown in FIG. 3, the junction portion 19 includes a screw
hole 56, a screw mounting hole 57, and a mounting screw 58. The
screw hole 56 is provided in one of the first holding member 15 and
the second holding member 16. In the present embodiment, the first
holding member 15 is provided with the screw hole 56, for example,
at a pitch of 120.degree. on the circumference edge of the second
mounting hole 24f The screw mounting hole 57 is provided in the
other of the first holding member 15 and the second holding member
16. In the present embodiment, the second holding member 16 is
provided with the screw mounting hole 57. The mounting screw 58 is
screwed to the screw hole 56 following insertion from the screw
mounting hole 57, and fixes the first holding member 15 to the
second holding member 16 in a state where the first junction
surface 17 and the second junction surface 18 are closely attached
to each other.
[0043] The diameter of the screw mounting hole 57 is formed to be
larger than the diameter of the mounting screw 58, and a gap is
formed between the both. Within this gap, the first holding member
15 and the second holding member 16 can be relatively shifted in
the direction of both the junction surfaces and be rotated around
the optical axis. Therefore, the second holding member 16 is moved
(moved in an XY plane) in the direction of the incidence-side
optical axis CL1I (hereinafter, called the X-axis direction) of the
first optical system 11 and a direction which is at right angles to
an X-axis (called the Y-axis direction) in the in-plane of the
first junction surface 17 with respect to the first holding member
15, and the emission-side optical axis CL1O of the first optical
system 11 and the incidence-side optical axis CL2I of the second
optical system 12 are caused to be coincident with a Z-axis
direction which is at right angles to the XY plane. In addition,
one of the first holding member 15 and the second holding member 16
is rotated around the Z-axis with respect to the other in addition
to its shift in an XY direction, and thus the incidence-side
optical axis CL1I of the first optical system 11 and the
emission-side optical axis CL2O of the second optical system 12 are
caused to be coincident with each other. The fine adjustment
thereof is performed in a state where the first holding member 15
and the second holding member 16 are relatively movable by loosely
fastening the mounting screw 58, and are given a frictional force
enough not to lightly move. In a case where the optical axis
alignment is terminated, the mounting screw 58 is finally fastened,
and the first holding member 15 and the second holding member 16
are formed integrally with each other.
[0044] At the time of the optical axis alignment, as shown in FIG.
4, the projection lens 10 is set up in a projector main body 60
described later, or a tester for optical axis alignment or an
exclusive projection instrument configured similarly to this
projector main body 60. At the time of the setup, the projection
lens 10 is detachably mounted to the projector main body 60 by a
mount 61 (see FIG. 1) having a well-known structure. A pattern
image of a rectangular frame or any other patterns is displayed on
the image forming panel 67. The pattern image displayed on the
image forming panel 67 is projected onto the screen 39 by the
projection lens 10. In a direction in which inclinations are
eliminated when viewing the amount of shift of this projected
pattern image from a reference position with respect to, for
example, the horizontal line and the vertical line of the
rectangular frame, the second holding member 16 is shifted in
X-axis direction and the Y-axis direction with respect to the first
holding member 15. Thereby, the optical axis alignment in the
X-axis and Y-axis directions is performed. In addition, in a case
where the rectangular frame projected onto the screen 39 is rotated
or distorted in a trapezoidal shape when the rectangular frame is
observed, the second holding member 16 is rotated around the
optical axis up to a position at which the rotation and distortion
of the rectangular frame do not appear. Thereby, the adjustment
around the optical axis is completed.
[0045] In the optical axis alignment, after the second holding
member 16 is rotated and adjusted around the optical axis, the
second holding member 16 may be shifted in the XY plane. In
addition, the optical axis alignment may be performed by
simultaneously performing its shift in the XY plane and its
rotation around the optical axis. This optical axis alignment is
also performed by a user after product purchase, in addition to
being performed at the final stage of a product.
[0046] As described above, the first holding member 15 and the
second holding member 16 are joined by the junction portion 19 in a
state where the first junction surface 17 and the second junction
surface 18 are aligned with each other, and thus the projection
lens 10 having a U-shaped optical path is assembled.
[0047] As shown in FIG. 4, the projection lens 10 is detachably
mounted to the projector main body 60 through the mount 61 (see
FIG. 1), and a projector 62 is formed. The projector main body 60
has a light source 66, an image forming panel 67, and a control
unit 68 received in a case 65 having a substantially rectangular
shape.
[0048] As the image forming panel 67, a transmission-type liquid
crystal panel is used. The light source 66 is installed on the rear
surface of the image forming panel 67, that is, the opposite side
of the projection lens 10 based on the image forming panel 67. As
the light source 66, an LED is used which simultaneously emits
three colors of RGB, and illuminates the image forming panel 67.
Meanwhile, a xenon lamp that emits white light or a halogen lamp
and an ultrahigh-pressure mercury lamp may be used instead of the
LED. The projection lens 10 projects illumination light, from the
image forming panel 67 illuminated by the light source 66, onto a
projection surface, for example, the screen 39.
[0049] The control unit 68 turns on the light source 66, and causes
an image of three colors of RGB to be displayed on an image forming
surface 67a. The control unit 68 also performs the following other
processes. When an operation signal of a zoom dial 71 is received,
for example, in a case where an electromotive control function is
contained in the projection lens 10, the size of an image projected
onto the screen 39 is adjusted. When an operation signal of a focus
dial 73 is received, a focusing mechanism (not shown) of the
projection lens 10 is brought into operation, and the focus of the
image projected onto the screen 39 is adjusted.
[0050] As shown in FIG. 1, the image is projected onto the screen
39 located further upward than the optical axis CL2O of the
projection lens 10. The center of the image forming panel 67 is
shifted and fixed to the lower side in a direction opposite to a
direction in which the central position of a projected image
(projection surface of the screen 39) shifts with respect to the
optical axis CL1I of the projection lens 10, that is, the direction
of the emission-side optical axis CL1O of the first optical system
11 of the projection lens 10.
[0051] At the time of use, as shown in (A) of FIG. 5, the image of
the image forming panel 67 (see FIG. 1) can be magnified and
projected by the projection lens 10 onto the screen 39 installed
upward on the rear surface side of the projector 62.
[0052] (B) of FIG. 5 shows a projector 101 of a first related art
type. This projector 101 has a V-shaped optical path along which an
image is projected onto the rear surface side of the projector 101
through one mirror. As compared with this projector 101, a lens
shift is possible in the projection lens 10 of the present
invention, and thus a projection position can be changed in a state
where the projector 62 is fixed. Furthermore, in a case where a
shift ratio S is 0.5 as shown in FIG. 1, the emission-side optical
axis CL2O of the second optical system 12 of the projection lens 10
and the lower side of a projected image can be caused to be
coincident with each other as shown in (A) of FIG. 5. Meanwhile, in
a case where a distance from the optical axis to the center of the
image forming panel 67 is set to Y, and the length of the image
forming panel 67 in the shift direction of the image forming panel
67 is set to H, the shift ratio S is obtained by dividing the
distance Y by the length H. Therefore, in the present embodiment, a
gap between the emission-side optical axis CL2O of the projection
lens 10 and the lower side of the projected image can be set to
"0". On the other hand, as shown in (B) of FIG. 5, in the projector
101 of the first related art type, a gap between the projected
image and the projection lens cannot be set to "0". For this
reason, a gap L1 is necessarily required in the projector 101 of
the first related art type. In the present embodiment, the gap can
be set to "0", a set length's worth of space securing is not
required, and the degree of freedom of installation increases,
which leads to an advantage in the installation space. Meanwhile,
the lens shift may be performed in a horizontal direction in
addition to a vertical direction.
[0053] (C) of FIG. 5 shows a projector 102 of a second related art
type having an I-shaped optical path in which an optical path is
not bent. In this projector 102, a projection distance+a set
length's worth of installation space of the projector 102 is as
long as a length L2. In the projector 62 of the present embodiment,
as shown in (A) of FIG. 5, projection can be performed in the
installation space of a set length L3 of the projector 62.
Therefore, the installation space can be made smaller to that
extent than in the projector 102 of the second related art type,
and the degree of freedom of installation also increases.
[0054] Meanwhile, in the present embodiment, as shown in FIG. 1,
the projection lens 10 is detachably mounted to the projector main
body 60 through the mount 61, but the first optical system 11 may
be fixed directly to the projector main body 60 instead of the
mount 61.
Second Embodiment
[0055] In the first embodiment, using a gap between the screw
mounting hole 57 provided in the second holding member 16 and the
mounting screw 58 screwed to the first holding member 15, the
second holding member 16 is shifted in the XY plane with respect to
the first holding member 15, and is rotated around the optical axis
(Z-axis). On the other hand, in a second embodiment shown in FIG.
6, an intermediate member 80, a first mounting screw 81, and a
second mounting screw 82 are provided to form a junction portion
83. In this junction portion 83, shift adjustment in the XY plane
and adjustment around the optical axis are separately performed
through the intermediate member 80. Meanwhile, the same
configuration members as those in the first embodiment are denoted
by the same reference numerals and signs, and thus the repeated
description thereof will be omitted below.
[0056] The intermediate member 80 is provided between the first
junction surface 17 and the second junction surface 18, and a shift
in the XY plane is performed by the first mounting screw 81 between
the first holding member 15 and the intermediate member 80. In
addition, adjustment around the optical axis is performed by the
second mounting screw 82 between the intermediate member 80 and the
second holding member 16. Therefore, a gap for shift adjustment
within the XY plane is provided between the first holding member 15
and the intermediate member 80. In addition, a gap for adjustment
around the optical axis is provided between the intermediate member
80 and the second holding member 16.
[0057] The intermediate member 80 is provided with a screw mounting
hole 84 in a circumferential direction on the outer circumference
edge, for example, at a pitch of 120.degree.. The screw hole 56 is
formed on the first junction surface 17 at a position corresponding
to the screw mounting hole 84. The first mounting screw 81 is
inserted into the screw mounting hole 84 and is screwed to the
screw hole 56, whereby the intermediate member 80 is mounted to the
first holding member 15. A gap is provided between the first
mounting screw 81 and the screw mounting hole 84, and optical axis
alignment in the direction of the XY plane is performed by a shift
of the intermediate member 80 in the XY plane within a range of
this gap. After the completion of the optical axis alignment, the
first mounting screw 81 is fastened, and the intermediate member 80
is fixed to the first holding member 15.
[0058] An intermediate junction surface 80a with which the second
junction surface 18 is in contact is formed on the upper surface of
the intermediate member 80. A screw hole 85 is formed on the outer
circumference edge of the intermediate junction surface 80a at a
position corresponding to the screw mounting hole 57 of the second
holding member 16. The second mounting screw 82 is inserted into
the screw mounting hole 57 of the second holding member 16, and is
screwed to the screw hole 85, whereby the second holding member 16
is mounted to the intermediate member 80. A gap is provided between
the screw mounting hole 57 and the second mounting screw 82, and
optical axis alignment around the Z-axis is performed by the second
holding member rotating around the Z-axis within a range of this
gap. After the completion of the optical axis alignment, the second
mounting screw 82 is fastened, and the second holding member 16 is
fixed to the intermediate member 80.
Third Embodiment
[0059] In a third embodiment shown in FIG. 7, an intermediate mount
86 is provided instead of the intermediate member 80 of the second
embodiment. The intermediate mount 86 has a well-known mount
structure, and junction between the intermediate mount 86 and the
second holding member 16 is detachably performed. The intermediate
mount 86 includes the same second junction surface 18 as that in
the first embodiment on the lower surface. The first holding member
15 includes the first junction surface 17, and the mounting screw
58 is screwed to the screw hole 56, whereby the intermediate mount
86 is fixed to the first holding member 15.
[0060] In a state where the second holding member 16 is mounted to
the intermediate mount 86, the first junction surface 17 of the
first holding member 15 is closely attached to the second junction
surface 18, similarly to the first embodiment. Thereafter, the
second holding member 16 is moved relative to the first holding
member 15, and a shift in the XY plane and rotation around the
Z-axis are performed, whereby the emission-side optical axis CL1O
of the first optical system of the first holding member 15 and the
incidence-side optical axis CL2I of the second optical system of
the second holding member 16 are aligned with each other. In a case
where the optical axis alignment is completed, the mounting screw
58 inserted into the screw mounting hole 57 is screwed to the screw
hole 56, and the intermediate mount 86 is fixed to the first
holding member 15.
[0061] At the time of use, similarly to the first embodiment, the
first holding member 15 is set up on the mount 61 of the projector
main body 60, and thus a projector is assembled. In a case where
the projection distance or projection angle of view of a projection
lens is changed, as shown in FIG. 8, the second holding member 16
is removed from the intermediate mount 86, and thus a third holding
member 87 including a third optical system, for example, having a
different projection focal length can be set up on the intermediate
mount. In a case of the present embodiment, only the second holding
member 16 including the second optical system 12 is replaced by the
third holding member 87, and thus the projection distance or the
projection angle of view can be easily changed. In addition, the
intermediate mount 86 is mounted to the first holding member 15 in
a state of optical axis alignment. Therefore, in a case where the
third holding member 87 that newly holds another third optical
system is set up, new optical axis alignment is not required and
thus the time and effort are saved. Meanwhile, optical axis
alignment may be readjusted, as necessary, with respect to the
third holding member 87 by the intermediate mount 86 being shifted
in the XY plane or rotated around the Z-axis with respect to the
first holding member 15.
[0062] Meanwhile, in the third embodiment, junction between the
intermediate mount 86 and the second holding member 16 is
detachably performed, but junction between the intermediate mount
86 and the first holding member 15 may be detachably performed. In
this case, optical axis alignment is performed between the
intermediate mount 86 and the second holding member 16.
Fourth Embodiment
[0063] In the respective embodiments, the shift in the XY plane for
fine adjustment or the rotation around the Z-axis is performed by
moving the second holding member 16 directly, for example, with a
hand. On the other hand, in a fourth embodiment shown in FIG. 9,
the second holding member 16 is slightly shifted or rotated with
respect to the first holding member 15, using fine adjustment
screws 91, 92, and 93. The fine adjustment screws 91 to 93 are
screwed to a bracket 94. The fine adjustment screws 91 to 93 are
advanced and retreated with respect to the bracket 94 by turning
these fine adjustment screws 91 to 93, and thus the shift and the
rotation can be performed. Meanwhile, the numbers of fine
adjustment screws 91 to 93 for shift or rotation and the
installation positions thereof may be appropriately changed. In
addition, though not shown in the drawings, for example, a gear
mechanism or a link mechanism capable of moving the first holding
member 15 and the second holding member 16 relative to each other
may be used in addition to the fine adjustment screws 91 to 93 and
the bracket 94.
[0064] In the above embodiment, a transmission-type liquid crystal
panel is used as the image forming panel 67, but a reflection-type
liquid crystal panel may be used. In this case, the image forming
panel 67 has the light source 66 installed on its front side and is
irradiated simultaneously with irradiation light beams of three
colors of RGB. In addition, in a case where a DMD is used as the
image forming panel 67, the light source 66 is installed on the
front side of the image forming panel 67, and an LED of three
colors of RGB is emitted in a time-division manner in
synchronization with a timing at which a three-color image of the
DMD is formed.
[0065] In the respective embodiments, a description has been given
in a state where the projector 62 is installed on a table, but the
present invention can be applied even in a case where the projector
is used in a state of hanging down from a ceiling or the like. In
addition, an example has been described in which an image is
projected onto the screen 39, but the projection surface is not
limited to the screen 39, and a projector that projects an image
onto various projection surfaces can be used.
[0066] In the above embodiment, a U-shaped optical path is formed
using the first mirror 13 and the second mirror 14, but the first
and second junction surfaces 17 and 18 and the junction portion 19
of the present invention may be applied to a projection lens which
is configured to form an L-shaped optical path by removing either
the first mirror 13 or the second mirror 14. Even in this case, it
is possible to provide a projection lens and a projector which are
capable of being accurately assembled while achieving a reduction
in size, and are capable of widening an angle by reducing a focal
length.
EXPLANATION OF REFERENCES
[0067] 10: projection lens [0068] 11: first optical system [0069]
12: second optical system [0070] 13: first mirror [0071] 14: second
mirror [0072] 15: first holding member [0073] 16: second holding
member [0074] 17: first junction surface [0075] 18: second junction
surface [0076] 19: junction portion [0077] 21: first lens [0078]
22: second lens [0079] 23: image forming surface [0080] 24: first
main body [0081] 24a: lower plate [0082] 24b: inclination portion
[0083] 24c: front plate [0084] 24d: first mounting hole [0085] 24e:
upper plate [0086] 24f: second mounting hole [0087] 25: mounting
cylinder [0088] 26: first lens frame [0089] 27: second lens frame
[0090] 28, 29: mounting screw [0091] 35: third lens [0092] 36:
fourth lens [0093] 37: fifth lens [0094] 38: sixth lens [0095] 39:
screen [0096] 40: second main body [0097] 40a: upper plate [0098]
40b: inclination portion [0099] 40c: lower plate [0100] 40d: third
mounting hole [0101] 40e: flange [0102] 41: mounting plate [0103]
41a: mounting hole [0104] 42: third lens frame [0105] 42a: flange
[0106] 43: fourth lens frame [0107] 44: fifth lens frame [0108] 46,
47, 48: mounting screw [0109] 56: screw hole [0110] 57: screw
mounting hole [0111] 58: mounting screw [0112] 60: projector main
body [0113] 61: mount [0114] 62: projector [0115] 65: case [0116]
66: light source [0117] 67: image forming panel [0118] 67a: image
forming surface [0119] 68: control unit [0120] 71: zoom dial [0121]
73: focus dial [0122] 80: intermediate member [0123] 80a:
intermediate junction surface [0124] 81: first mounting screw
[0125] 82: second mounting screw [0126] 83: junction portion [0127]
84: screw mounting hole [0128] 85: screw hole [0129] 86:
intermediate mount [0130] 87: third holding member [0131] 91, 92,
93: fine adjustment screw [0132] 94: bracket [0133] 101, 102:
projector [0134] CL1, CL1I, CL1O, CL2, CL2I, CL2O: optical axis
[0135] L1: gap [0136] S: shift ratio [0137] Y: distance
* * * * *