U.S. patent number RE42,740 [Application Number 11/802,079] was granted by the patent office on 2011-09-27 for projector.
This patent grant is currently assigned to Seiko Epson Corporation. Invention is credited to Motoyuki Fujimori, Toshiaki Hashizume, Kenji Iguchi, Kiichi Okumura.
United States Patent |
RE42,740 |
Fujimori , et al. |
September 27, 2011 |
Projector
Abstract
A projector for separating white light into three primary
colors, forming images with liquid crystal light valves, mixing
these images, and projecting an enlarged picture of the mixed
images with a projection lens. The projector includes an optical
unit having a light source, a plurality of dichroic mirrors for
separating the white light into blue, green, and red beams,
respective liquid crystal light valves forming images of the blue,
green, and red colors. The optical unit has a chassis with a rigid
center portion at which one of the liquid crystal light valves is
mounted, the other two light valves being mounted symmetrically
with respect thereto. An adjustment mechanism is provided for
matching pixels of the second and third color valves with those of
the first color valve. The red color liquid crystal light valve is
disposed midway between the blue and green color liquid crystal
light valves and a cooling fan is disposed below the red color
liquid crystal light valve.
Inventors: |
Fujimori; Motoyuki (Suwa,
JP), Hashizume; Toshiaki (Okaya, JP),
Iguchi; Kenji (Okaya, JP), Okumura; Kiichi
(Kusatsu, JP) |
Assignee: |
Seiko Epson Corporation (Tokyo,
JP)
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Family
ID: |
27549399 |
Appl.
No.: |
11/802,079 |
Filed: |
May 18, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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09362623 |
Jul 28, 1999 |
Re. 40296 |
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07938261 |
Oct 21, 1992 |
5418586 |
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Reissue of: |
08394308 |
Feb 24, 1995 |
5651599 |
Jul 29, 1997 |
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Foreign Application Priority Data
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Feb 22, 1991 [JP] |
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03-028430 |
Mar 22, 1991 [JP] |
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03-059137 |
Jun 10, 1991 [JP] |
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03-137633 |
Jun 27, 1991 [JP] |
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03-049295 |
Jun 27, 1991 [JP] |
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03-156408 |
Jun 27, 1991 [JP] |
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03-156422 |
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Current U.S.
Class: |
353/61; 353/58;
353/38; 353/119; 353/31 |
Current CPC
Class: |
H04N
9/3105 (20130101); H04N 9/3141 (20130101); H04N
9/3144 (20130101); H04N 9/317 (20130101) |
Current International
Class: |
G03B
21/14 (20060101) |
Field of
Search: |
;353/31,33,34,37,119,57,58,60,61 ;349/5,7,8,9 ;362/264,345 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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6312301 |
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May 1918 |
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JP |
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5288337 |
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Jul 1977 |
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JP |
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61-14034 |
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Aug 1986 |
|
JP |
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2314051 |
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Sep 1988 |
|
JP |
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01-289912 |
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Nov 1989 |
|
JP |
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01-302387 |
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Dec 1989 |
|
JP |
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02-047642 |
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Feb 1990 |
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JP |
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2-73622 |
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Jun 1990 |
|
JP |
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02-195384 |
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Aug 1990 |
|
JP |
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02-196280 |
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Aug 1990 |
|
JP |
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02-275984 |
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Nov 1990 |
|
JP |
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2-287542 |
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Nov 1990 |
|
JP |
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287452 |
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Nov 1990 |
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JP |
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3-207777 |
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Jan 1991 |
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JP |
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03-024532 |
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Feb 1991 |
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JP |
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4040509 |
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Feb 1992 |
|
JP |
|
4040605 |
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Feb 1992 |
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JP |
|
4310913 |
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Nov 1992 |
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JP |
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63-123019 |
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May 1998 |
|
JP |
|
Other References
Japanese Patent Office Notification of Reasons for Refusal for
Application No. H11-040586 mailed Feb. 27, 2001 with English
translation. cited by other .
Japanese Patent Office Notification of Reasons for Refusal for
Application No. H11-040617 mailed Feb. 27, 2001 with English
translation. cited by other .
Japanese Patent Office Notification of Reasons for Refusal for
Application No. H11-040661 mailed Feb. 27, 2001 with English
translation. cited by other.
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Primary Examiner: Dowling; William C
Attorney, Agent or Firm: Oliff & Berridge, PLC
Parent Case Text
.Iadd.Notice: More than one reissue application has been filed for
the reissue of U.S. Pat. No. 5,651,599. The reissue applications
are application Ser. Nos. 09/362,623 (reissue of U.S. Pat. No.
5,651,599, now issued as RE 40,296), 11/802,079 (the present
application, which is a continuation reissue of Ser. No. 09/362,623
filed Jul. 28, 1999). .Iaddend.
This application is a divisional of U.S. Pat. No. 07/938,261, filed
Oct. 21, 1992 and now U.S. Pat. No. 5,418,586.
Claims
What is claimed is:
.[.1. A projector-type liquid crystal projector comprising a light
source; a plurality of color separating means for separating light
emitted by said light source into beams of blue, green and red
colors; optical means including image forming liquid crystal light
valves and image synthesizing means for synthesizing images for the
respective blue, green and red beams which are arranged in an
optical path; and a projection lens, said color separating means,
said image forming liquid crystal light valves, and said image
synthesizing means being secured to a top surface of a box-shaped
lower chassis by fixing members, an outer case being secured to
side surfaces of said lower chassis separate from said top
surface..].
.[.2. A projector-type liquid crystal projector comprising a light
source, a plurality of color separating means for separating light
emitted by said light source into beams of blue, green and red
colors; optical means including image forming liquid crystal light
valves and image synthesizing means for synthesizing images for the
respective blue, green and red beams which are arranged in an
optical path; and a projection lens, cooling fans being positioned
in a plane over a surface on which said image forming liquid
crystal light valves are secured, said image forming liquid crystal
light valves being operatively associated with said cooling fans by
being positioned directly in the path of cooling air produced by
said cooling fans..].
.[.3. A projector-type liquid crystal projector comprising a light
source; a plurality of color separating means for separating light
emitted by said light source into beams of blue, green and red
colors; optical means including image forming liquid crystal light
valves and image synthesizing means for synthesizing images for the
respective blue, green and red beams which are arranged in an
optical path; and a projection lens, said light source including a
light tube and a lamp reflector housed in a lamp housing; an
exhaust fan being arranged near one side surface of the lamp
housing to cover one side surface of the lamp housing and exhaust
air at said one side surface, a hole for air suction and exhaust
being formed in a second side surface of said housing opposed to
said one side surface of said housing, a lamp fan being positioned
further forward than an opening of the lamp reflector and laterally
of the lamp housing..].
.[.4. A projector as claimed in claim 3, further comprising an air
regulating plate for controlling air flow to the light tube, said
air regulating plate being disposed in the path of flowing air of
said lamp fan..].
.Iadd.5. A liquid crystal projector, comprising: a light source
including a light tube and a lamp reflector housed in a lamp
housing; a plurality of color separators that separate light
emitted by the light source into beams of blue, green and red
colors; image forming liquid crystal light valves; an image
synthesizer that synthesizes images for the blue, green and red
beams respectively; a projection lens; an exhaust fan arranged near
a first side surface of the lamp housing; a lamp fan positioned
further forward than an opening of the lamp reflector and laterally
of the lamp housing; and an opening through which air is blown into
the lamp housing by the lamp fan, the opening being formed in a
second side surface of the lamp housing. .Iaddend.
.Iadd.6. A projector, comprising: a light source; separation
optical elements that separate light emitted by the light source
into beams of blue, green and red colors; liquid crystal light
panels that modulate respective ones of the separated blue, green
and red beams; a synthesizing optical system that synthesizes the
modulated blue, green and red beams; a projection lens that
receives the synthesized light from the synthesizing optical
system; a chassis having a bottom member, wherein the separation
optical elements, the liquid crystal light panels and the
synthesizing optical system are secured so as to be constrained
against movement relative to the bottom member; and an outer case
to which the chassis is secured. .Iaddend.
.Iadd.7. A projector as claimed in claim 6, wherein the chassis
further comprises a plurality of walls, each of which is positioned
substantially perpendicular to the bottom member. .Iaddend.
.Iadd.8. A projector as claimed in claim 7, wherein the outer case
is secured to the bottom member or any of the plurality of walls.
.Iaddend.
.Iadd.9. A projector as claimed in claim 7, wherein the bottom
member and the plurality of walls form an enclosure. .Iaddend.
.Iadd.10. A projector as claimed in claim 7, wherein at least one
wall includes a projection that extends substantially parallel to
the bottom member. .Iaddend.
.Iadd.11. A projector as claimed in claim 6, wherein the separation
optical elements include two dichroic mirrors. .Iaddend.
.Iadd.12. A projector as claimed in claim 6, wherein the
synthesizing optical system includes two dichroic surfaces.
.Iaddend.
.Iadd.13. A projector comprising: a light source including a light
tube and a lamp reflector housed in a lamp housing; separation
optical elements that separate light emitted by the light source
into beams of blue, green and red colors; liquid crystal light
panels that modulate respective ones of the separated blue, green
and red beams; a synthesizing optical system that synthesizes the
modulated blue, green and red beams; a projection lens that
receives the synthesized modulated light from the synthesizing
optical system; an exhaust fan arranged near a first side surface
of the lamp housing; a lamp fan positioned further forward than an
opening of the lamp reflector and laterally of the lamp housing;
and an opening through which air is blown into the lamp housing by
the lamp fan, the opening being formed in a second side surface of
the lamp housing. .Iaddend.
.Iadd.14. A projector as claimed in claim 13, further comprising an
air regulating plate that controls air flow to the light tube, the
air regulating plate being disposed in a path of flowing air
generated by the lamp fan. .Iaddend.
.Iadd.15. A projector as claimed in claim 13, wherein the
separation optical elements include two dichroic mirrors.
.Iaddend.
.Iadd.16. A projector as claimed in claim 13, wherein the
synthesizing optical system includes two dichroic surfaces.
.Iaddend.
.Iadd.17. A projector as claimed in claim 13, wherein the
synthesizing optical system includes two dichroic layers.
.Iaddend.
.Iadd.18. A projector, comprising: a lamp housing having first and
second side surfaces; a light source including a light tube and a
lamp reflector housed in the housing; a light valve that modulates
light emitted by the light source; a projection lens that receives
the modulated light from the light valve; an exhaust fan arranged
near the first side surface of the lamp housing; a lamp fan
positioned further forward than an opening of the lamp reflector
and laterally of the lamp housing; and an opening through which air
is blown into the lamp housing by the lamp fan, the opening being
formed in the second side surface of the lamp housing.
.Iaddend.
.Iadd.19. A projector as claimed in claim 18, the exhaust fan being
an axial flow fan..Iaddend.
.Iadd.20. A projector as claimed in claim 18, the lamp fan being a
scirocco fan..Iaddend.
.Iadd.21. A projector as claimed in claim 18, further comprising:
an air regulating section that guides air to a region surrounded by
a reflection surface of the lamp reflector..Iaddend.
.Iadd.22. A projector as claimed in claim 21, the air regulating
section being disposed in the lamp housing..Iaddend.
.Iadd.23. A projector as claimed in claim 21, the air regulating
section being disposed between the lamp housing and the lamp
fan..Iaddend.
.Iadd.24. A projector as claimed in claim 18, further comprising:
an air regulating section that controls air flow to the light
tube..Iaddend.
.Iadd.25. A projector as claimed in claim 24, the air regulating
section being disposed in a path of flowing air generated by the
lamp fan..Iaddend.
.Iadd.26. A projector as claimed in claim 18, the exhaust fan
having blades with an outer diameter that is equal to or larger
than a diameter of the opening of the lamp reflector..Iaddend.
.Iadd.27. A projector as claimed in claim 18, the lamp fan being
smaller than a diameter of the opening of the lamp
reflector..Iaddend.
.Iadd.28. A projector as claimed in claim 18, the lamp fan being
smaller than an outer diameter of blades of the exhaust
fan..Iaddend.
.Iadd.29. A projector as claimed in claim 26, the exhaust fan being
an axial flow fan..Iaddend.
.Iadd.30. A projector as claimed in claim 27, the lamp fan being a
scirocco fan..Iaddend.
.Iadd.31. A projector as claimed in claim 28, the exhaust fan being
an axial flow fan..Iaddend.
.Iadd.32. A projector as claimed in claim 28, the lamp fan being a
scirocco fan..Iaddend.
.Iadd.33. A projector as claimed in claim 18, further comprising:
an air regulating section that guides air to a region surrounded by
a reflection surface of the lamp reflector, the exhaust fan having
blades with an outer diameter that is equal to or larger than a
diameter of the opening of the lamp reflector..Iaddend.
.Iadd.34. A projector as claimed in claim 18, further comprising:
an air regulating section that guides air to a region surrounded by
a reflection surface of the lamp reflector, the lamp fan being
smaller than an outer diameter of blades of the exhaust
fan..Iaddend.
.Iadd.35. A projector as claimed in claim 18, further comprising:
an air regulating section that controls air flow to the light tube,
the air regulating section being disposed in a path of flowing air
generated by the lamp fan, the exhaust fan having blades with an
outer diameter that is equal to or larger than a diameter of the
opening of the lamp reflector..Iaddend.
.Iadd.36. A projector as claimed in claim 18, further comprising:
an air regulating section that controls air flow to the light tube,
the air regulating section being disposed in a path of flowing air
generated by the lamp fan, the lamp fan being smaller than an outer
diameter of blades of the exhaust fan..Iaddend.
.Iadd.37. A projector as claimed in claim 18, the exhaust fan being
an axial flow fan, and the lamp fan being positioned further
forward than an axis of the exhaust fan..Iaddend.
.Iadd.38. A projector as claimed in claim 26, the exhaust fan being
an axial flow fan, and the lamp fan being positioned further
forward than an axis of the exhaust fan..Iaddend.
.Iadd.39. A projector as claimed in claim 28, the exhaust fan being
an axial flow fan, and the lamp fan being positioned further
forward than an axis of the exhaust fan..Iaddend.
.Iadd.40. A projector as claimed in claim 18, further comprising: a
power unit, the lamp fan being disposed in a path of air flowing
from the power unit to the light source..Iaddend.
.Iadd.41. A projector as claimed in claim 18, further comprising: a
power unit being located on the air intake side of the lamp
fan..Iaddend.
.Iadd.42. A projector as claimed in claim 18, further comprising: a
power unit, and an optical unit including an optical part, the lamp
fan being disposed between the power unit and the optical
unit..Iaddend.
.Iadd.43. A projector as claimed in claim 18, further comprising: a
lamp stabilizing unit that stabilizes the light emitted by the
light source, the lamp fan being disposed in a path of air flowing
from the lamp stabilizing unit to the light source..Iaddend.
.Iadd.44. A projector as claimed in claim 18, further comprising: a
lamp stabilizing unit that stabilizes the light emitted by the
light source, and an optical unit including an optical part, the
lamp fan being disposed between the lamp stabilizing unit and the
optical unit..Iaddend.
Description
TECHNICAL FIELD
The present invention relates to a projection type liquid crystal
projector for separating white light obtained from for example a
video tape into three primary colors, forming images with liquid
crystal panels (liquid crystal light valves), mixing the images,
and projecting an enlarged picture with a projection lens.
RELATED ARTS
In a conventional projection type liquid crystal projector as
disclosed in Japanese Patent Laid-Open Publication Serial No. SHO
63-247720, white light is separated into three primary colors with
dichroic mirrors. With liquid crystal light valves respective
images of these colors are formed. Thereafter, with an image mixing
mirror, these images are mixed. Next, with a projection lens, the
mixed image is enlarged and then projected.
With the above-mentioned projection type liquid crystal projector,
pixel positions of the liquid crystal light valves, which form
blue, green, and red images, cannot be relatively adjusted. In
addition, due to deviation of the mounting angles of reflection
mirrors disposed in the respective optical paths to the projection
lens, the optical axis is deviated. Moreover, due to deviation of
the mounting angles of the liquid crystal light valves to their
optical axes, when the three primary colors are mixed, the
resultant image is deviated. The deviations of positions of the
liquid crystal light valves for blue, green, and red colors to the
projection lens result in an out-of-focus image. As a result, the
quality of picture being projected is deteriorated.
To solve these problems, the mounting position and the mounting
angle of the liquid crystal light valve for each color should be
adjusted. Nevertheless, in the conventional apparatuses, only a
means for moving the mounting positions with eccentric pins or
adjustment screws is provided. However, in the apparatus where the
positions of the liquid crystal light valves are adjusted with the
eccentric pins, the rotating direction of the eccentric pin and the
moving direction of each liquid crystal light valve are not
uniformly determined. Thus, the adjustment of movement to a desired
direction is very difficult to do. In addition, the eccentric pins
are not easy to machine. Moreover, E rings, nuts, and so forth are
required to secure the eccentric pins. Consequently, the number of
parts increases and the assembling work takes a long time,
resulting in raising the production cost of the apparatus.
On the other hand, so far, the conventional liquid crystal light
valves are designed and produced for use in designated colors. In
particular, the specifications of the liquid crystal light valves
for forming a green image whose relative visibility is high are
severe. In contrast, the specifications of the liquid crystal light
valve for forming a blue image whose specific visibility is low are
comparatively less severe. Thus, even if a liquid crystal light
valve which can be satisfactorily used for blue color cannot be
used for green color. Therefore, in this situation, this valve
should be treated as an unacceptable item. Consequently, the yield
of these liquid crystal light valves is low, thereby raising the
production cost.
In addition, the conventional projection type liquid crystal
projector is provided with two fans which are an air intake fan and
an air exhaust fan as cooling means. With these fans, the interior
of the apparatus is cooled. However, lacking sufficient analysis of
the air flow paths and so forth, the spherical portion of a light
source (metal halide lamp), an UV and IR filter portion, polarizing
plate, a liquid crystal panel, electric parts for an exhaust
opening, electric devices, and so forth are not satisfactorily
cooled. Thus, these constructional parts are heated to temperatures
close to their limit values. On the other hand, there are demands
of brighter projectors of low-noise in the marketplace. However,
the conventional cooling means cannot satisfy such demands. Unless
the above-mentioned constructional parts are satisfactorily cooled,
problems such as deteriorating image quality and decreasing service
life would take place. An increase of the size and weight of the
projector is not permitted and, the conventional techniques have
not satisfied such requirements. In particular, the light source is
not satisfactorily cooled.
SUMMARY OF THE INVENTION
An object of the present invention is to enable a projection type
liquid crystal projector to clearly display images and to provide a
projector which is small in size, easy to adjust, and high in
reliability. Another object of the present invention is to provide
a projection type liquid crystal projector having high cooling
efficiency by an arrangement of relevant constructional parts, of
small and thin construction, and excellent properties with respect
to operability, durability, and maintainability. A further another
object of the present invention is provide a projection type liquid
crystal projector having a projection light source which is free of
deteriorations of image quality such as deviations of intensity,
colors, and picture elements (pixels) and a lighting unit having a
long service life as the light source.
The projection type liquid crystal projector according to the
present invention comprises optical means, comprising a light
source, a plurality of dichroic mirrors for separating white light
emitted by the light source into beams of blue, green, and red
colors, respective liquid crystal light valves for forming images
of the beams of blue, green, and red colors so as to form optical
paths, and a projection lens, wherein the optical means is
characterized in that at a center portion of a chassis made of
rigid members a first color type valve of the liquid crystal light
valves for forming the blue, green, and red colors, second and
third color type valves of the liquid crystal light valves being
disposed at positions symmetrical to the first color valve, and
wherein the projection type liquid crystal projector further
comprises an adjustment mechanism for mutually matching pixels of
the second and third color valves with those of the first color
valve.
Thus, the positions and angles of the liquid crystal light valves
can be easily and securely adjusted. In addition, the deviations of
color images and out-of-focus condition can be prevented.
Consequently, the quality of the projected images can be
improved.
The adjustment mechanism includes a plurality of members slidable
relative to each other and provided with notches. Into these
notches, a tool such as a screwdriver can be inserted so as to
perform an adjustment operation.
The chassis on which the liquid crystal light valves, mirrors, and
so forth are fixed is made of a metal plate. The periphery of the
chassis is formed by bending or drawing operations.
In addition, the projection type liquid crystal projector according
to the present invention comprises a white lamp, dichroic mirrors
for separating light of the white lamp into beams of three colors
of red, green, and blue, and liquid crystal light valves for
transmitting the beams of three colors and for forming images,
wherein a blue color type valves for forming a blue image of the
liquid crystal light valves has the same construction as a green
color type valve thereof so as to have compatibility with each
other.
Further, the projection type liquid crystal projector according to
the present invention comprises a case substantially of a
rectangular parallelepiped shape, a base plate disposed in the
case, a lamp housing unit having a projection light source, an
optical unit, comprising image forming liquid crystal light valves,
light mixing and separating mirrors, dichroic mirrors,
prepolarizers, and a projection lens, the lamp housing unit and the
optical unit being disposed on the base plate so that a main
optical path and the outer shape is of a plane L shape, the
projection lens facing a window of the front of the case, one end
of the lamp housing unit facing a window of a lamp housing cover on
a side of the case and the other an air exhaust opening in the rear
of the case, a power unit and a lamp stabilizer disposed in a space
surrounded by the plane L shape portion, the front and the side of
the case, an air intake regulating plate disposed below the liquid
crystal light valves, an air intake fan disposed below the air
intake regulating plate, a video board disposed between a side of
the case and the light guide unit, a liquid crystal drive board
unit disposed midway between the top of the case and the top of the
light guide unit, an air exhaust fan disposed midway between the
air exhaust opening in the rear of the case and the lamp housing
unit, and a lamp fan disposed in front of a light emitting surface
of the lamp housing unit.
Furthermore, as cooling means of the light source, the air exhaust
fan disposed adjacent to the lamp housing and a small blowing lamp
fan disposed adjacent to a reflector opening portion of the lamp
reflector are provided.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic plan view showing optical paths and principal
parts of an optical system in accordance with the present
invention;
FIG. 2 is a partial assembly sectional view showing a part of an
adjustment mechanism for fixing and moving in the focus direction a
liquid crystal light bulb in accordance with the present
invention;
FIG. 3 is a partial assembly plan view of FIG. 2;
FIG. 4 is an assembly exploded view showing an adjustment mechanism
for matching pixels of the liquid crystal light bulbs;
FIG. 5 is a partial assembly exploded view showing a part of FIG.
4;
FIG. 6 is a partial assembly exploded view showing the adjustment
mechanism for fixing and moving in the focus direction the liquid
crystal light bulbs, the mechanism being used for reference of
matching the pixels;
FIG. 7 is a perspective view showing a modified embodiment of an
adjustment and operation mechanism portion;
FIG. 8 is a detail view of FIG. 7;
FIG. 9 is a plan view showing an application of the adjustment and
operation mechanism portion;
FIG. 10 is an exploded perspective view of a chassis and a
cover;
FIG. 11 is a perspective view showing the chassis;
FIGS. 12 and 13 are plan views showing the compatibility of liquid
crystal light bulbs;
FIG. 14 is a schematic assembly plan view showing the entire
construction of the present invention;
FIG. 15 is a sectional view showing an optical;
FIG. 16 is a detail assembly plan view showing the optical
unit;
FIG. 17 is a plan view showing the case;
FIG. 18 is a front view of the case;
FIG. 19 is a rear view of the case;
FIG. 20 is a bottom view of the case;
FIG. 21 is a partial assembly plan view;
FIG. 22 is a plan view showing parts of an air intake regulating
plate of FIG. 14;
FIG. 23 is a plan view showing parts of a lower light guide of FIG.
22;
FIG. 24 is a rear view showing parts of the lower light guide;
FIG. 25 is a side view showing parts of the lower light guide;
FIG. 26 is a front view showing parts of the lower light guide;
FIG. 27 is a sectional view showing parts of the lower light
guide;
FIG. 28 is an assembly plan view showing a lamp housing unit and
portions adjacent thereto;
FIG. 29 is an assembly left side view excluding the case;
FIG. 30 is an assembly sectional view showing a lamp cover and
portions adjacent thereto;
FIG. 31 is an assembly plan view showing a lamp fan block;
FIG. 32 is an assembly plan view showing the lamp fan block;
FIG. 33 is a front view showing window frame parts;
FIG. 34 is an assembly sectional view showing the lamp housing unit
and portions adjacent thereto;
FIG. 35 is an assembly rear view showing the lamp housing unit and
the portions adjacent thereto;
FIG. 36 is an assembly side view showing the lamp housing unit and
the portions adjacent thereto;
FIG. 37 is an assembly sectional side view showing an inner
housing;
FIG. 38 is an assembly sectional front view showing the inner
housing;
FIG. 39 is an assembly front view showing the inner housing;
FIG. 40 is an assembly left side view showing the inner
housing;
FIG. 41 is an assembly front view showing the inner housing;
FIG. 42 is a left side view showing outer housing parts;
FIG. 43 is an assembly right side view showing the outer housing
parts;
FIG. 44 is a plan view showing the outer housing parts;
FIG. 45 is a front view showing inner housing parts;
FIG. 46 is a side view showing lamp connector plate parts;
FIG. 47 is a plan view showing the lamp connector plate parts;
FIG. 48 is a circuit block diagram of a lamp fan;
FIG. 49 is a circuit block diagram of a lamp fan;
FIG. 50 is a plan view of an air intake regulating plate;
FIG. 51 is a plan view of an air intake regulating plate;
FIG. 52 is a bottom view showing a case;
FIG. 53 is a rear view showing the case;
FIG. 54 is a bottom view showing the case;
FIG. 55 is a rear view showing the case;
FIG. 56(a) to (d) are schematic diagrams showing test results of
iso-speed distribution of an air intake fan;
FIG. 57 is a perspective front view showing the construction of a
lighting unit including a cooling means of a lamp; and
FIG. 58 is a perspective side view showing the lighting unit.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
FIG. 1 is a schematic plan view showing an optical system of an
embodiment according to the present invention. Reference numeral 1
is a light source. Reference numeral 2 is a blue dichroic mirror
which reflects blue light and allows other colors of light to pass
through (hereinafter, this mirror is referred to as B.D.M.).
Reference numerals 3a and 3b are red dichroic mirrors which reflect
red light and allows other colors of light to pass through
(hereinafter these mirrors are referred to as R.D.M.). Reference
numerals 4a and 4b are reflection mirrors. Reference numeral 5 is a
dichroic mirror which allows green light to pass through, reflects
other colors of light, and mixes red, green, and blue colors of
light (hereinafter, this mirror is referred to as a mixing mirror).
Reference numerals 6a, 6b, and 6c are condenser lenses. Reference
numeral 7a is a liquid crystal light valve for forming an image of
blue light. Likewise, reference numerals 7b and 7c are liquid
crystal light valve for forming images of red and green colors of
light, respectively. Reference numeral 8 is a chassis for holding
and fixing the above-mentioned parts. Reference numeral 9 is a
projection lens. The above-mentioned parts 2, 3a, 3b, 4a, 4b, 5,
6a, 6b, 6c, 7a, 7b, 7c, which are fixed and held with the chassis
8, form an optical means.
Now, the path of light in the optical means will be described. The
light source 1 generates white light 1w. The B.D.M. 2 reflects only
the rays in the wavelength range of blue, namely blue color 1b of
light 1w and the other rays of light in other wavelength ranges
(yellow light) to pass through. The R.D.M. 3a only reflects rays
having a wavelength range of red 1R of the light 1Y and allows the
remaining green rays 1G to pass through. The beam of rays 1G is
condensed by the condenser lens 6c and then an image is formed
thereby as a beam 1g. The beam 1g is reflected beam the reflection
mirror 4b. Thereafter, the beam 1g passes through the mixing mirror
5. Then, the beam 1g is projected onto a screen by the projection
lens 9. The blue beam 1B is reflected by the reflection mirror 4a.
Then, the blue ray 1B passes through the condenser lens 6a.
Thereafter, the liquid crystal light valve 7a forms an image as a
ray 1b. Then, the ray 1b passes through the R.D.M. 3b and comes to
the mixing mirror 5. Likewise, the red ray 1R passes through the
condenser lens 6b and comes to the liquid crystal light valve 7b.
Then, the liquid crystal light bulb 7b forms an image as a ray 1r.
The ray 1r is reflected with the R.D.M. 3b and then comes to the
mixing mirror S. The mixing mirror 5 reflects the rays 1b and 1r
mixes the rays of three primary colors 1g, 1b, and 1r as a
displayable picture. The projection lens 9 projects the picture on
the screen.
It should be appreciated that the liquid crystal light valve 7b
disposed in the middle position of the optical means can be used
for the red ray of light, the liquid crystal light valve 7a for
green ray of light, and the liquid crystal light valve 7c for blue
ray of light. Since each dichroic mirror disposed in the optical
path has an inclination to the optical axis, different optical
paths take place. Thus, in this construction, singe green ray
having high relative visibility is not used, astigmatism and
thereby unsharpness can be prevented.
To clearly display a picture, it is necessary to mix the rays 1g,
1b, and 1r in such a way that their mutual positions do not
deviate. Thus, the mutual pixel positions of the liquid crystal
light valves 7a, 7b, and 7c should be accurately matched each
other. In addition, these pixel positions should be precisely
matched with the back-focus position of the projection lens 9. FIG.
4 is a perspective view showing an example of a fixing and
adjusting mechanism of the liquid crystal light valve 7a. As shown
in the figure, the liquid crystal light valve 7a is mounted on a
circuit board 10. The board 10 is fixed to Z shaped bend portions
(four positions) disposed on a fixing plate 11 with screws 13. One
side of the fixing plate 11 is positioned with an oval hole 11b and
a dowel 12a formed on a fixing plate 12. In addition, a screw 14
pivoted with a bend portion 12b on the fixing plate 12 is connected
to a bend portion 11c of the fixing plate 11. Thus, the fixing
plate 11 is laterally slidably supported with the fixing plate 12.
The fixing plate 11 and the fixing plate 12 are fixed with screws
15 (two positions) through spring washers 16. In the center of the
fixing plate 12, an opening portion 12a is formed. About the center
of the opening portion 12c, arc shape holes 12d (three positions)
are formed as outer concentric circles. Dowels 19a (three
positions) formed on the fixing plate 19 are positioned and guided
in the holes 12d. In addition, an eccentric pin 17 connected to an
oval hole 12e formed on the fixing plate 12 and rotatably secured
with a washer 18 is pivotally supported in a hole 19b formed on the
fixing plate 19. Thus, the rotation of the fixing plate 12 can be
adjusted by the amount of eccentricity for which the eccentric pin
17 is rotated. In addition, a washer 20 connected to (the rear of)
a dowel on the fixing plate 19 is fixed to a screw hole 12f formed
on the fixing plate 12 with a screw 22 which pierces a deformed
hole 19d formed on the fixing plate 19 through a spring washer 21.
Thus, the fixing plate 12 and the fixing plate 19 can be fixed. A
notch 19f at a lower portion of an opening portion 19e formed in
the center of the fixing plate 19 is connected to a dowel 23a
formed on a fixing plate 23. Thus, one side of the fixing plate 19
is positioned and guided to the fixing plate 23. On the other hand,
a screw 24 pivotally supported with a bend portion 19g of the
fixing plate 19 is connected to a screw hole 23c formed on a bend
portion 23b over the fixing plate 23. Thus, the fixing plate 19 is
positioned and guided relative to the fixing plate 23 so that the
longitudinal position of the liquid crystal light valve 7a can be
adjusted. The fixing plate 19 is fixed in such a way that screws 25
(two positions) which pierce respective oval holes 23d (two
positions) formed on the fixing plate 23 are connected to screw
holes 19i (two positions) formed on the fixing plate 19 through
respective spring washers 26 (two positions).
In the above-mentioned construction, by moving pixels of the liquid
crystal light valve 7a in the horizontal, vertical, and rotational
directions, these pixels can be matched with those of the liquid
crystal light valves 7b. In addition, to more securely fix the
liquid crystal light valve 7a, screws 27 (two positions) which
pierce respective oval holes 11d (two positions) formed on the
fixing plate 11, respective oval holes 12g (two positions) formed
on the fixing plate 12, respective oval holes 19h formed on the
fixing plate 19 (two positions) are connected to respective screw
holes 23e (two positions) formed on the fixing plate 23 through
respective spring washers 28 (two positions). By controlling the
tightening torque of the screws 21, they allow the fixing plate 11,
the fixing plate 12, and the fixing plate 19 to be resiliently
fixed to the fixing plate 23 by the use of a resilient force of the
spring washers 28. Thus, since the fixing plates 11, 12, 19, and 23
can be temporarily fixed to each other by frictional forces, mutual
displacements thereof can be prevented during an adjustment
operation. After the adjustment mechanism has been mounted, the
screws 27 are present at unaccessible positions (see FIG. 2). Thus,
the permanent tightening operation can be omitted. Likewise, since
the spring washers 16, 21, and 26 allow the position of the liquid
crystal light valve 7a to be adjusted, when the above-mentioned
screws and so forth are tightened, the resilient forces of these
spring washers 16, 21, and 26 prevent the mechanism from being
displaced.
In the above-mentioned adjustment mechanism, the fixing plate 11,
the fixing plate 12, the fixing plate 19, and the fixing plate 23
have the same center dimensions in their outer shapes (in left and
right directions). Thus, by assembling these fixing plates 11, 12,
19, and 23 in such a way that these outer shapes are matched, a
position accuracy without a significant deviation to the desired
center can be obtained. In addition, by providing a means for
forming a gap between each connecting surface of the fixing plates
11, 12, 19, and 23, the gap prevents warping, distortion and so
forth of parts from badly affecting the liquid crystal light valve
7a.
Next, a mechanism for fixing and adjusting the position of the
liquid crystal light bulb 7a on the chassis 8 will be described in
detail. FIG. 2 is a schematic assembly sectional view showing a
part of the adjustment mechanism in the above-mentioned
construction. FIG. 3 is a schematic assembly plan view of FIG. 2.
As shown in FIGS. 1, 2, and 4, an upper fixing auxiliary plate 29
is pivotally guided on a bend portion 23b over the fixing plate 23
in such a way that a dowel 23f formed on the bend portion 23b can
be rotated. In addition, the upper fixing auxiliary plate 29 is
connected to an eccentric pin 30 which is rotatably secured to the
bend portion 23b. Thereafter, the upper fixing auxiliary plate 29
is temporarily fixed to the bend portion 23b with screws 31 (two
positions). The upper fixing auxiliary plate 29 is temporarily
fixed to an upper chassis 8a with screws 32 through screw holes 29a
(two positions) formed on the upper fixing auxiliary plate 29. A
dowel 29c formed on the upper fixing auxiliary plate 29 is
connected in an oval hole (not shown in the figure) on the upper
chassis plate 8a. In addition, a screw 33 pivotally held with a
bend portion 8c formed on the upper chassis plate 8a is connected
to a bend portion formed on the upper fixing auxiliary plate 29
with a screw. Thus, the mechanism can adjust the focus direction of
the liquid crystal light valve 7a. Since the eccentric pin 30 can
be adjusted from an opening portion (not shown in the figure)
formed on the upper chassis plate 8a. Thus, the amount of angular
deviation in the direction perpendicular to the optical axis of the
liquid crystal light valve 7a can be adjusted. After the
above-mentioned two adjustment operations are completed, by
permanently tightening the screws 31 and 32, the upper direction of
the adjustment mechanism is fixed.
Next, with reference to FIGS. 2, 4, and 5 (FIG. 5 is a perspective
view seen in the direction of the arrow in FIG. 4), the adjustment
and fixing of the adjustment mechanism in the lower direction will
be described. Dowels 8d (two positions) and an eccentric pin 35 are
rotatably secured to a lower chassis plate 8b. The dowels 8d and
the eccentric pin 35 allow the lower fixing auxiliary plate 34 to
be positioned. A bend portion 23g formed on the fixing plate 23 is
guided with a dowel 34a and mounted to the auxiliary plate 34. With
screws 36 (two positions), the lower fixing auxiliary plate 34 and
the bend portion 23g are temporarily fixed. In addition, with
screws 37 (two positions), the lower fixing auxiliary plate 34 and
the lower chassis plate 8b are temporarily fixed. The focus
adjustment in the lower direction is performed in accordance with
the mount of eccentricity of the eccentric pin 35. Thereafter, the
screws 37 (two positions) are permanently tightened. After the
angle adjustment in the plane direction to the upper optical axis
is completed, the screws 36 are permanently tightened along with
the screws 31. Obviously, the plane positions of the dowels 23f and
34a have been matched to each other in the reference dimensions. In
addition, screwdriver access holes for tightening the screws 36 and
37 and rotating the eccentric pin 35 are formed on the bend portion
23b of the fixing plate 23 and the upper fixing auxiliary plate 29
(this part will be described later in detail).
Next, as shown in FIG. 3, pixels in the horizontal direction can be
adjusted from a side direction of the chassis with a screwdriver
because the screw 14 is disposed at the opening portion formed on a
side of the chassis 8. As described above, the adjustment of
deviation of pixels in the vertical, horizontal, and rotational
directions is performed in the adjustment mechanism. The deviation
of plane angle between the focus direction (including the vertical
direction) and the direction of the optical axis is adjusted with
fixing portions for fixing the adjustment mechanism and the
chassis.
The liquid crystal light valve 7c is disposed such that light
valves 7c and 7a are symmetrical with respect to the liquid crystal
light valve 7b.
Next, a supporting and fixing mechanism of the liquid crystal light
valve 7b disposed at a center portion of the chassis 8 will be
described. When the liquid crystal light valve 7b can be disposed
within the depth of focus of the projection lens 9, the lack of
sharpness of pixels projected on the screen does not affect the
visibility by human eyes. However, in the cases of the mounting of
the liquid crystal light valve 7b and the construction of this
embodiment, where the chassis 8 is made of metal plates and so
forth, due to the overall effects of the tolerances involved in the
constructional elements and the machining tolerances, the position
of the liquid crystal light valve 7b is not always placed in the
range of the above-mentioned allowable depth of focus. Thus, the
adjustment mechanism for allowing the focus direction to be
adjusted is required. An example of this mechanism will be
described with reference to FIG. 6. As shown in FIG. 6, in an
adjustment mechanism for adjusting the upper direction of the
liquid crystal light valve 7b, the bulb 7b is mounted on a circuit
board 41 which is fixed to convex portions (four positions) formed
on a fixing plate 42 with screws 40 (four positions). In addition,
a lower fixing auxiliary plate 44 is positioned and guided to the
lower chassis plate 8b with dowels 8e (two positions) formed on the
lower chassis plate 8b and an eccentric pin 43 rotatably secured to
the lower chassis plate 8b. The lower fixing auxiliary plate 44 is
temporarily fixed with screws 49 (two positions). A dowel 44a
provided on the lower fixing auxiliary plate 44 is rotatably
connected in a hole 42c formed in the center of a bend portion 42b
formed on the fixing plate 42. Thereafter, the fixing plate 42 and
the fixing auxiliary plate 44 are temporarily fixed with screws 45
(two positions). The fixing auxiliary plate 47 which is pivoted
with a dowel 42e at a center portion of a bend portion 42d formed
over the fixing plate 42 and which is positioned and guided with an
eccentric pin 46 rotatably secured to a hole 42f is temporarily
fixed with a screw 50. Dowels 47a (two positions) disposed on the
upper fixing auxiliary plate 47 and an eccentric pin 48 rotatably
secured are positioned and guided in oval holes 8f (two positions)
and 8g (one position) formed on the upper chassis plate 8a. Then,
the upper fixing auxiliary plate 47 is temporarily fixed to the
upper chassis plate 8a with screws 51 (three positions). Of course,
the upper chassis plate 8a has screwdriver access holes (see FIG.
7) so that screws and so forth mounted below the upper chassis
plate 8a can be mounted and removed. In the focus adjustment
operation, the upper direction of the focus is adjusted by the
mount of eccentricity of the eccentric pin 48. Likewise, the lower
direction of the focus is adjusted by the amount of eccentricity of
the eccentric pin 43. In addition, the angular deviation in the
plane direction to the optical axis is adjusted by the amount of
eccentricity of the eccentric pin 46. After the above-mentioned
adjustment operations are complete the screws 49, 45, 50, and 51
are permanently tightened so as to securely fix the adjustment
mechanism. Thus, all the adjustment operations of this mechanism
can be performed. If the position of the liquid crystal light valve
7b were in the allowable range of depth of focus of the backfocus
of the projection lens by means of simplified mount construction of
the liquid crystal light valve 7b or improved machining accuracy
thereof, the above-mentioned adjustment mechanism could be
omitted.
As described above, since the angular deviation in the plane
direction to the optical axis is adjusted only in the direction of
the chassis plate 8a, the adjustment operation and the mechanism
thereof are simplified. In addition, by horizontally forming a
90.degree. bend portion (not shown in the figure) at an end of each
of the fixing plate 23 and the fixing plate 42, along with the
reinforcement of their fixing plates and the improvement of the
surface accuracy thereof, disturbing light can be effectively
prevented. In addition, when the bend portions 23b, 23g, 42b, and
42d formed on the fixing plate 23 and the fixing plate 42 fixed
between the chassis plates 8a and 8b are fixed with screws, errors
of the bend angles of the bend portions become bending moments.
These bending moments are applied to these chassis plates. To
suppress this bad influence applied to the liquid crystal light
valves 7a and 7b and the deviation of the adjustment mechanism, at
the base of each bend portion, an opening portion is formed so as
to reduce the amount of bending.
In particular, since the chassis plates 8a and 8b, the fixing
plates 11, 12, 19, 23, and 42, the upper fixing auxiliary plates 29
and 47, the lower fixing auxiliary plates 34, and 44, and so forth
are made of the same material such as steel parts, they have the
same coefficient of linear expansion. Thus, the parts of the
adjustment mechanism uniquely expand and shrink.
In addition, the position accuracy of the positioning holes and
dowels on the chassis 8 for use with the fixing mechanisms of the
mirrors and, the liquid crystal light valves is of the order of
approximately 10 microns. Moreover, a simple construction is used
in such a way that the liquid crystal light valves are directly
fixed to the fixing plate 23. Further, the allowable depth of focus
of the backfocus of the projection lens 9 can be reduced to
approximately 200 microns or less. Furthermore, when the size of
the liquid crystal light valves is of approximately 3 inches and
the number of pixels thereof is of the order of approximately
100,000, a construction which does not require the adjustment in
the focus direction can be satisfactorily accomplished. In
addition, when the amount of deviation of pixels in the horizontal
and vertical directions is approximately 1/2 to 2/3 times the
amount of the related art, a construction which does not require
the matching of pixels can be also accomplished.
As described above, according to the above-mentioned construction,
with reference to pixels of a first liquid crystal light valve
disposed in the center of the chassis, pixels of a second liquid
crystal light valve disposed point-symmetrically to the first
liquid crystal light valve are adjusted. Thus, the mechanism for
fixing the liquid crystal light valve disposed in the center of the
chassis can be constructed simply and in a small size. Therefore,
an optical system with a short optical path can be designed.
Consequently, this construction can contribute to reducing the size
of the optical system, namely, the size of the final product.
In addition, since the position adjustment operation of the liquid
crystal light valve disposed in the center of the chassis can be
performed from the top thereof, the disability of adjustment from
the side thereof due to the constructional restriction can be
compensated. Moreover, since the adjustment operation of the liquid
crystal light valves disposed point-symmetrically to another valve
is available from the top and the side, the number of operation
steps can be reduced. Furthermore, since the adjustment operation
from the side can be performed by using a simple adjustment jig in
the final product state where the optical apparatus is mounted in a
real machine, the adjustment quality is improved.
Since the shapes of the parts of the fixing and adjustment
mechanism of the liquid crystal light valves disposed
point-symmetrically can be formed symmetrically to those of the
valve disposed in the center of the chassis, the number of design
and machining steps can be reduced.
In addition, since the constructional parts of the adjustment
mechanism can be assembled in accordance with their outer shapes,
the assembled adjustment mechanism can have the nearly designed
accuracy. Thus, the adjustment operation can be easily estimated
and the number of working steps can be reduced. Moreover, by the
accomplishment of the construction in a small size, the projection
lens and the mirrors can have high cost performance. In addition,
the construction in the small size contributes to decreasing the
size of the final product and reducing the costs of the apparatus
and the final product.
Since the liquid crystal light valves and polarizing plates (not
shown in the figure) are exposed to strong light, they become hot.
To maintain the performance of these parts, a forced cooling
mechanism is required. To accomplish this mechanism, a fan 60 for
drawing outside air is disposed below the chassis 8b (see FIG. 1).
To equally cool the liquid crystal light valves and the polarizing
plates, the center portion of the fan 60 should be disposed in the
vicinity of the liquid crystal light valve 7b disposed at the
center portion of the chassis 8b. However, since a motor is
disposed at the center portion of the fan, the amount of air blown
is low. To improve the air blown capacity, the amount of air blow
is adjusted by using a regulating plate. However, in the present
invention, since the fixing mechanism of the liquid crystal light
valve 7b disposed at the center portion of the chassis is
simplified, the fluid resistance is decreased. Thus, without a
particular regulating means, the fixing mechanism of the liquid
crystal light valve 7b contributes to the improvement of the
cooling efficiency.
Since the constructional parts of the optical apparatus are made of
the same material, they equally expand and shrink for temperature
changes. Thus, the deviation of positions in the adjustment
mechanism can be suppressed. In other words, since the deviation of
pixels between the liquid crystal light valves are suppressed, the
quality and accuracy of the pictures can be improved.
As described in the last part of the above-mentioned embodiment,
when light incident on the projection lens 9 causes red and green
rays to be reflected by a mixing mirror, the adjustment accuracy of
matching pixels of the liquid crystal light valve 7b for red with
those of the liquid crystal light valve 7a for green can be
improved in a relatively small number of adjustment steps. When
light enters the projection lens, since red and green rays are
reflected on the same surface of the mixing mirror 5, the amount of
deviation of the optical axis due to the deviation of position of
the mixing mirror 5 for the red rays is the same as that of the
green rays. Thus, the amount of deviation of the red and green rays
is equal to the amount of deviation due to the deviation of
position of the R.D.M. 3b and the amount of deviation between the
mutual positions of the liquid crystal light valves 7a and 7b.
Consequently, the amount of deviation becomes small. In addition,
since the pixels of the liquid crystal light valve 7a can be stably
matched with those of the liquid crystal light valve 7b, they can
be adjusted in a small number of adjustment steps. On the other
hand, with respect to the blue rays, in addition to the amount of
deviation of the optical axis due to the deviation of position of
the mixing mirror 5, the deviation of the optical axis due to the
deviation of position of the reflection mirror 4b and the amount of
deviation between the mutual positions of the liquid crystal light
valve 7b and 7c are added. Thus, the number of adjustment steps
increases in accordance with the amount of deviation. However,
since the relative visibility of the blue rays is low, even if
there is still a minor error to adjust, the error does not affect
the picture quality.
In addition to setting the sizes of the liquid crystal light
valves, the number of pixels, and the allowable depth of focus of
the projection lens, when the improvement of the machining accuracy
of parts and the simplification of the fixing mechanisms of the
liquid crystal light valves are accomplished, the construction
which does not require the adjustment of the focus direction with
respect to the position of the liquid crystal light valve disposed
at the center portion of the chassis can be accomplished.
Alternatively, the construction which requires only the adjustment
for placing the liquid crystal light valve to a position
perpendicular to the optical axis can be accomplished. Thus, the
mechanism can be further simplified. In addition, the construction
which does not require the adjustment of matching pixels can be
accomplished. Consequently, such a construction allows the cost
reduction including the reduction of the number of production steps
and parts. Thus, the present invention contributes to reducing the
cost of products which were expensive.
FIGS. 7 and 9 show a practical example of an adjustment adjustment
and operation mechanism which can be adjusted with a screwdriver.
These figures present a light valve mounting surface where the
liquid crystal light valve is mounted and adjustment positions of
the light valve are obtained.
As shown in FIG. 7 which presents an embodiment of the adjustment
and operation mechanism, a liquid crystal light valve is mounted on
a light valve board 50. The light bulb board 50 is fixed to a light
valve fixing plate 51 with screws. A dowel 51a of the light valve
fixing plate 51 is rotatably guided by a lower adjustment plate 52.
A dowel 51b of the light valve fixing plate 51 is rotatably guided
by an upper adjustment plate 53. The light valve fixing plate 51 is
fixed to the lower adjustment plate 52 with screws. The lower
adjustment plate 52 is slidably connected to the lower light guide
54 with oval holes 52a and dowels 54a formed thereon. The lower
adjustment plate 52 is fixed to the lower light guide 54 with
screws. The upper adjustment plate 53 is slidably connected to an
upper light guide 55 with an oval hole 53a and a dowel 55a. The
upper adjustment plate 53 is connected to the upper light guide 55
with screws. The lower light guide 54 and the upper light guide 55
are spaced apart by columns 56. The lower light guide 54 and the
upper light guide 55 are fixed to the column 56 with screws.
The upper adjustment plate 53 has a notch 53b. The upper light
guide 55 opposed to the notch 53b has a hole 55b which the same
shape as the notch 53b. A space formed with the notch 53b and the
hole 55b has a shape where the tip of the screwdriver D can be
inserted regardless of the position of the upper adjustment plate
53 in its allowable slidable range. FIG. 8 shows a detail of the
shapes of the notch and hole. By loosening a screw which fixes the
upper adjustment plate 53 and the upper light guide 55 and rotating
the tip of screwdriver D inserted into the space between the notch
53b and the hole 55b, the upper adjustment plate 53 is guided and
slid with the oval hole 53a and the dowel 55a. Thus, an upper
portion of the light valve fixing plate 51 rotatably guided with
the upper adjustment plate 53 approach or goes away from the
projection lens 57. The direction in which the light valve fixing
plate 51 moves corresponds with the direction that the screwdriver
D rotates.
Likewise, by loosening a screw which fixes the lower light guide 54
and the lower adjustment plate 52 and rotating the tip of the
screwdriver inserted into the space between a notch 52b and a hole
54b, the lower adjustment plate 52 is guided and slid with the oval
hole 52a and the dowel 54a. Thus, a lower portion of the light
valve fixing plate 51 rotatably guided with the lower adjustment
plate 52 approaches and goes away from the projection lens 57.
The light valve fixing place 51 has a notch 51c. The lower
adjustment plate 52 opposed to the notch 51c has a hole 52c which
has the same shape as the notch 51c. By loosening a screw which
fixes the light bulb fixing plate 51 and the lower adjustment plate
52 and rotating the tip of the screwdriver inserted into the space
between the notch 51 and the hole 52c, the light valve fixing plate
51 rotates about a line which passes through the dowel 51a and the
dowel 51b. At this point, the direction in which the driver rotates
corresponds with the direction that the light valve fixing plate 51
rotates.
In the above-mentioned construction, only by removing the screws
which fix the upper adjustment plate 53 and the light valve fixing
plate 51, the adjustment mechanism can be dismounted from the light
guide. Thus, the workability in the assembling process and
after-service is very high.
FIG. 9 shows an example where the combination of the
above-mentioned notch and hole is used for an alignment adjustment
mechanism of a three-plate projection type liquid crystal
projector. In the three-plate liquid crystal projection apparatus,
to match the apparent positions of the three R, G, and B liquid
crystal panels, the apparent positions of at least two liquid
crystal panels should be adjusted in the horizontal, rotational,
and vertical directions. In an example shown in FIG. 9, a
horizontal adjustment plate 58 has a plurality of notches so as to
widen the adjustment range. By forming holes with the same shape as
the notches on the rotation adjustment plate 59, adjustment portion
can be disposed at any positions of the rotation adjustment plate
59 rather than the notches disposed on the periphery thereof. Thus,
the degree of freedom can be improved in designing the rotation
adjustment plate 59. In FIG. 9, reference numeral 60 is a vertical
adjustment plate.
Consequently, in the above-mentioned construction, the position of
the light valve can be adjusted with a minimum number of parts. In
addition, since the tip of screwdriver fits in the space between
the notch and the hole, the screwdriver does not fall during the
adjustment work. Moreover, since the direction in which the
screwdriver rotates corresponds to the direction in which the light
valve moves, the adjustment can be easily performed.
By applying the above-mentioned adjustment and operation mechanism
to the matching of pixels of the liquid crystal light valves 7a,
7b, and 7c, the mechanism can be simplified.
As described above, in the projection type liquid crystal
projector, light of a white light source is separated into rays of
three colors of red, green, and blue with dichroic mirrors.
Thereafter, the rays of these colors enter liquid crystal panels.
Next, these rays are mixed by dichroic mirrors. Then, the mixed
rays are projected onto a screen by a projection lens. Thus, if the
accuracies of the positions and angles of the dichroic mirrors
(B.D.M.) and the reflection mirrors 4a and 4b are low, the optical
axis of each color deviates from positions of a accurate color and
irregular coloration takes place in the composed picture
(hereinafter, this situation is referred to as unevenness of
colors). Moreover, in this situation, images projected from the
panels also deviate from matched or aligned positions (hereinafter,
this situation is referred to as deviation of pixels).
In this embodiment, since the lower chassis plate 8b, which mounts
the dichroic mirrors, reflection mirrors, and so forth, is made of
a metal plate, the production cost of the lower chassis plate 8b is
low. In addition, the accuracy of the metal mold is very high.
Thus, the lower chassis plate 8b can be quantitatively produced
with high accuracies of positions and angles of part mounting
holes. In other words, since there is no deviation of each color,
the optical system units free of unevenness of colors and deviation
of pixels can be quantitatively produced. The design of the units
can be easily changed by slightly modifying the design of the metal
mold.
If a liquid crystal projector were constructed in such a way that
the optical system unit, which mounts the dichroic mirrors,
reflection mirrors, and so forth, is fixed to an outer case with
screws, the lower chassis plate would be exposed to an excessive
force. Thus, the positions and angles of the dichroic mirrors,
reflection mirrors, and so forth, which are mounted on the lower
chassis plate, would deviate. Thereby, the optical axes in the
optical system unit would deviate, resulting in occurrences of
unevenness of colors and deviation of pixels. However, in this
embodiment, the periphery of the lower chassis plate is processed
by a bending operation, the adjacent portion being processed by
spot welds 8i, the resultant plate being formed in a box shape by
drawing or the like. Thus, the strength of the lower chassis plate
can be maintained, thereby preventing the positions and angles of
the dichroic mirrors, reflection mirrors, and so forth from
deviating. Consequently, the strength of the optical system unit
can be maintained, so that unevenness of colors and deviation of
pixels can be prevented. When the lower chassis plate is fixed to
the outer case and other board at three points in the vicinity of
the beam mixing portion or in the vicinity of the separating
portion, the forge applied to the lower chassis plate can be
decreased. This is because there are many vent openings on the
cooling upper and lower chassis plates in the vicinity of the
liquid crystal light valve. Thus, the strength of these portions is
high. When the lower chassis plate is fixed to a portion with a
high strength in the region between the lamp to the liquid crystal
light valve or the region between the liquid crystal light valve
and the reflection lens, of the lower chassis plate can be made
flat. On the other hand, the mounting portion of the projection
lens is not in a box shape. Thus, the strength of this portion is
low. However, by placing the upper chassis plate 8a on the lower
chassis plate in the same box shape as the upper chassis plate, the
relevant strength can be kept. As described above, this embodiment
is suitable for quantitatively producing liquid crystal video
projectors which can project beautiful pictures.
Next, with reference to FIGS. 10 and 11, an embodiment of the
liquid crystal video projector will be described. FIG. 10 is a
perspective view showing a lower chassis of the optical system unit
of the liquid crystal projector according to the present invention.
The lower chassis plate 8b is made of metal. The periphery of the
lower chassis plate 8b is bent or drawn so that the lower chassis
plate 8b is formed in a box shape. The lower chassis plate 8b has
mounting holes 8h. Fixing frames which fix the dichroic mirrors,
reflection mirrors, and so forth are mounted and fixed to these
holes. Since the lower chassis plate 8b is made of metal, its
production cost is low. In addition, by slightly modifying the
shape of the metal mold of the lower chassis plate 8b, the design
of the lower chassis plate 8b can be changed wholly or partially.
Moreover, since the lower chassis plate 8b is constructed in the
box shape by bending or drawing the strength thereof is maintained.
Thus, when the lower chassis plate 8b is fixed to an outer case of
a liquid crystal video projector with screws, even if an excessive
force is applied to the lower chassis plate 8b, the positions and
angles of the part mounting holes thereof would not deviate.
Thus, deviations of positions and angles of the reflection mirrors,
which have been known as a cause of unevenness of colors and
deviation of pixels, can be solved and thereby more beautiful
pictures can be projected.
In a liquid crystal video projector shown in FIG. 12, light from a
white light source is separated into rays of three colors of red,
green, and blue with separating dichroic mirrors 2 and 3a. The rays
of separated colors enter liquid crystal light valves 7b, 7a, and
7c. Thereafter, the rays of separated colors are mixed by mixing
dichroic mirrors 3b and 5. Next, the mixed rays are projected onto
a screen by a projection lens 9.
In this case, if any liquid crystal light valve has a point defect,
a portion of the relevant color of red, green, and blue may not
always be lit. Thus, the color of this portion changes. This point
detect is not significant at the periphery of the screen, but it is
in the center. In addition, the point defect of blue color whose
relative visibility is low is not significant, while that of green
color whose relative visibility is high is significant. Thus, the
liquid crystal light valve for green requires higher precision than
that for blue. In other words, if the high specifications were
maintained, the yield of the liquid crystal light valve for green
would be lower than that of the liquid crystal light valve for
blue.
To prevent this disadvantage, when the liquid crystal light valve
for green is of the same construction as that for blue, that is,
both the liquid crystal light valves have compatibility to each
other, the better one can be used for green so as to decrease
significant green point defects. In a quantitative production
stage, liquid crystal light valve which are not suitable for green
can be sometimes used for those for blue. Thus, when the liquid
crystal light valves for green are used for those for blue, the
yield thereof can be improved. In addition, since the number of
types of liquid crystal light valves to be designed and produced is
reduced from three to two, the cost thereof can be decreased.
In a liquid crystal video projector shown in FIG. 13, light from a
white light source is separated into rays of three colors of red,
green, and blue with separating dichroic mirrors 2 and 2a. The rays
of separated colors enter liquid crystal light valves 7b, 7a, and
7c. Thereafter, the rays of separated colors are mixed by mixing
dichroic mirrors 3b and 5. The mixed rays are projected onto a
screen by a projection lens 9. However, the liquid crystal light
valves are susceptible to heat. When these liquid crystal light
valves are exposed to strong light, the temperature thereof rises
and thereby accelerating the deterioration thereof. To solve this
problem, a cooling fan 66 mounted in the vicinity of the liquid
crystal light valves is rotated so as to generate wind. This wind
cools the liquid crystal light valves so as to prevent them from
deteriorating.
In this embodiment, the red color type liquid crystal light valve
7b is disposed midway between the green color type liquid crystal
light valve 7a and the red color type liquid crystal light valve
7c. Below the red color type liquid crystal light valve 7c, the
cooling fan 66 is disposed. The wind produced by the cooling fan 66
cools the three liquid crystal light valves. When the cooling fan
66 is rotated, it allows wind to satisfactorily blow the blue and
green color type liquid crystal light valves 7c and 7a disposed
outside of the red color type liquid crystal light valve 7b.
The cooling fan 66 according to this embodiment is of a blade type.
When the cooling fan 66 is rotated, the wind force in the periphery
thereof is stronger than that in the center thereof. The wavelength
of rays of light which enter each liquid crystal light valve
differs from each other. The energy of rays of blue region which
enters the blue color type liquid crystal light valve is higher
than that of the green and red regions. Thus, singe the temperature
of the blue color type liquid crystal light valve rises most, the
necessity of cooling this valve is highest. In contrast, since the
energy of rays which enter the red color type liquid crystal light
valve is least and the temperature of this valve does not greatly
rise, the necessity of cooling this valve is comparatively low. In
addition, singe rays which enter each liquid crystal light valve
have been passed through an infrared ray cutting filter after being
emitted from the light source, infrared rays do not enter each
liquid crystal light valve.
Thus, as described in the above-mentioned embodiment, the cooling
fan 66 is disposed below the red color type liquid crystal light
valve 7b so that wind produced by the cooling fan 66 satisfactorily
blows against the blue and red color type liquid crystal light
bulbs. In other words, the blue color type liquid crystal light
valve which is highly heated by the rays with high energy is
disposed at the peripheral portion of the cooling fan where the
wind force is strong and the red color type liquid crystal light
valve which is less heated by the rays with low energy is disposed
at the center portion of the cooling fan where the wind force is
weak. Consequently, each liquid crystal light valve can be
effectively cooled without cooling loss. In addition, with one fan,
the plurality of liquid crystal light valves can be cooled. In
addition to reducing the cost of the product, the weight and size
thereof can be decreased.
In this embodiment, an image produced by entering rays of red
region separated by the separating dichroic mirrors 2 and 3a into
the liquid crystal light valve 7a (hereinafter this image is
referred to as a red image) and an image produced by entering rays
of greed region separated likewise (hereinafter this image is
referred to as a green image) are mixed by the dichroic mirror 3b.
Thereafter, the mixed image and an image produce by entering rays
of blue region into the liquid crystal light valve 7c (hereinafter
this image is referred to as a blue image) are mixed by the
dichroic mirror 5. Thus, a mixed image with three colors of red,
green, and blue can be obtained.
In the above-mentioned embodiment, by decreasing the thickness of
the red color mixing dichroic mirror 3b, the astigmatism of the
green image which passes through this mirror 3b is decreased.
However, when the thickness of the dichroic mirror is decreased,
the surface accuracy of the red mixing dichroic mirror 3b
deteriorates and thereby lowering the accuracy of the reflection.
Thus, it is assumed that the resolution of the red image being
reflected degrades. However, since the distance between the red
mixing dichroic mirror 3b and the red color type liquid crystal
light valve 7b is small, the degradation of the surface accuracy of
the red mixing dichroic mirror does not significantly affect the
image quality. Moreover, in this embodiment, by increasing the
thickness of the mixing dichroic mirror 5, the surface accuracy is
maintained and thereby the resolution of the image mixed by the red
mixing dichroic mirror 3b is maintained. However, when the
thickness of the mixing dichroic mirror 5 is increased, the
astigmatism of the blue image transmitted in the mixing dichroic
mirror 5 becomes large. Nevertheless, since the relative visibility
of the blue image is lower than that of the green and red images,
it is not significant.
Thus, in the embodiment shown in FIG. 12, since the green color
type liquid crystal light valve 7a and the blue color type liquid
crystal light valve 7c are interchangeably used, point defects of
the green image with high relative visibility can be decreased. A
liquid crystal light valve which is not suitable for the green
color liquid crystal light valve 7a can be sometimes used as one
for blue. Thus, the yield can be improved. Conventionally, three
types of liquid crystal light valves have been designed and
produced. However, according to this embodiment, the number of
types of liquid crystal light valves can be reduced from three to
two. Thus, cost reduction can be accomplished.
In the embodiment shown in FIG. 13, the red color type liquid
crystal light valve 7b is disposed midway between the green color
type liquid crystal light valve 7a and the blue color type liquid
crystal light valve 7c. The cooling fan 66 which allows wind to
satisfactorily blow against the green and blue type color liquid
crystal light valves 7a and 7b is disposed below the red color type
liquid crystal light valve 7b. Thus, the blue color type liquid
crystal light valve which is heated most can be effectively cooled
down. Consequently, without cooling losses, the single fan can cool
down the plurality of liquid crystal light valves. Therefore, in
addition to reducing the production cost, the weight and size
thereof can be decreased.
Moreover, in the embodiment shown in FIG. 12, by decreasing the
thickness of the red color mixing dichroic mirror 3b, the
astigmatism of a green image whose relative visibility is high can
be decreased. By increasing the thickness of the mixing dichroic
mirror, the surface accuracy thereof can be improved. Thus, the
image mixed by the red color mixing dichroic mirror 5 can be
precisely reflected.
FIGS. 14 to 56 show practical examples of the overall construction
including a cooling unit of the liquid crystal projector of the
present invention. FIG. 14 is a schematic assembly plan view seen
from the top of the liquid crystal projector.
The liquid crystal projector of the present invention has a case 70
which is substantially of a rectangular parallelepiped shape. The
case 70 accommodates all parts, functionally separated as units. As
shown in FIGS. 17 to 19, the case 70 comprises a lower case 72 and
an upper case 71 which can be separated at a separation line
73.
At front symmetrical positions of the bottom of the lower case 72,
a pair of threaded adjusters 74 for adjusting the vertical position
of a projected picture are provided. At a position below an optical
unit 75 (which will be described later), an air intake slit portion
76 is formed. At rear symmetrical positions of the lower case 72, a
pair of fixing members 71 are disposed.
A window 78 of the projection lens is formed at a position slightly
left of the center of the case 70. By sliding a cover plate 78
sidewardly, the window 79 is open. Since the cover plate 79 is bent
in an arc shape. it slides along an arcuate path.
At a right position of the rear of the case 70, an inter-face board
frame unit 80 for connecting each interface is attached from the
top. At a left position of the rear of the case 70, an air exhaust
fan cover 81 is attached from the top. In the center of the air
exhaust fan cover 81, an air exhaust opening 82 is formed. As shown
in FIG. 19, at a lower center position of the rear of the case 70,
a power receptacle 83 is disposed.
At a left position of the rear of the case 70, a lamp housing cover
85 for accessing an inner housing 154 is disposed.
At a position left of the center of the top of the upper case 71, a
speaker hole portion 86 for conveying sound generated by a speaker
is formed. On the speaker hole portion 86, a speaker cover 87 made
of a punched plate having small holes is disposed. At a front
position of the top of the upper case 71, an operation panel 88 on
which the user effects for example image, sound, and autofocus
adjustment operations is disposed. At a rear position at the center
of the top of the upper case 71, a power switch button 89 is
disposed.
A base plate 90 is detachably mounted on the lower case 72 with
screws.
On the base plate 90, an optical unit 98 (see FIG. 28) where a lamp
housing unit 91 and a projection lens unit 92 are assembled in a
light guide unit 102 is disposed in such a way that the main
optical path is in an L shape when viewed from the top thereof (see
FIG. 14). In addition, the projection lens unit 9 faces the window
78 in the from of the case 70. Moreover, the access direction of an
inner housing 154 of the lamp housing unit 91 faces the lamp
housing cover 85 on the left of the case 70.
A power unit 95 is disposed in the front of the lamp housing unit
91 and on the air intake side. A lamp stabilizing unit 96 is
disposed on the left of the projection lens unit 9. A video board
unit 97 is disposed outside the optical unit 75. The lamp housing
unit 91, the power unit 95, the stabilizing unit 96, the video
board unit 97, and the optical unit 96 are separately and
detachably mounted on the base plate 90.
The power unit 95 and the lamp stabilizing unit 96 are accommodated
in a shield case having a plurality of holes for drawing and
exhausting air. The speaker 99 is fixed to the power unit 95
through the shield case.
A drive board unit 100 has a liquid crystal drive circuit, a
microcomputer built-in system control circuit, and so forth. The
drive board unit 100 is disposed at the top of the optical unit 75.
The drive unit 100 has board holes 101 for routing cables for the
liquid crystal light panels and air flow paths thereof. These holes
101 are formed over the respective liquid crystal light valves.
These holes 101 allow air to flow to the top of the drive board
unit 100.
The air intake fan 66, which is an axial flow fan, is mounted on
the base plate 90 below the light guide unit 102. An integrally
formed inlet air regulating plate 105 disposed midway between the
air intake fan 66 and the light guide unit 102 allows fresh air
drawn through the air intake slit portion 76 and a dust protecting
filter 104 disposed on the bottom to branch into at least three
flow routes toward the liquid crystal light valves and into a
plurality of flow paths in the direction perpendicular to the air
blow opening.
The optical unit 98 is the above-mentioned optical means.
Hereinafter, the above-mentioned upper chassis plate 8a is referred
to as an upper light guide 121 and the lower chassis plate 8b as a
lower light guide 126. Then, these light guides 121 and 126 will be
described in detail.
As shown in FIG. 22, the air intake regulating plate 105 is
connected to a guide hole 107 of the lower light guide 126.
Thereafter, by inserting screws in the fixing holes 108f the air
intake regulating plate 105 is fixed to the lower light guide. The
air intake fan 66 is disposed at a position perpendicular to the
three liquid crystal light valves 7c (7a, and 7b), which are
disposed in a crank shape. In addition, these three liquid crystal
light valves 7a, 7b, and 7c are disposed in a projection area with
the air blow diameter of the air intake fan 66. As a result, the
distance between the air blow opening 111 and each of liquid
crystal light valves 7a, 7b, and 7c becomes short. In addition, the
temperatures of the liquid crystal light valves 7a, 7b, and 7c and
the polarizing plates 112 can be decreased.
A second embodiment of the air intake regulating plate 105 has
basically a cylindrical shape as shown in FIG. 50. A third
embodiment of the air intake regulating plate has a construction
where two curved branching walls and a straight wall are added to
the construction of the first embodiment, the branching walls being
connected inwardly from the periphery of the air intake regulating
plate to the straight wall which is disposed in parallel with the
surface of the liquid crystal light valve. The axial flow fan
causes wind to blow in an inclined direction which is the same as
the rotating direction of the fan blades. FIG. 56(a) shows a result
of air speed data of the axial flow fan. From this figure, it is
known that when no obstacles (such as net and filter) are present
in the air intake side of the axial flow fan, although the center
portion of iso-speed curve a is low, the curve is extended toward
the front of the blades. When there are obstacles, as shown in FIG.
56(b), the overall speed of the axial flow fan decreases and the
curve a is extended in the vicinity of the air blow opening. Thus,
the wind blows outward. In the second embodiment, the iso-speed
curve shown in FIG. 56(c) is obtained. The speed and direction of
wind of the second embodiment as shown in FIG. 56(c) are superior
to those of the related art as shown in FIG. 56(b). The iso-speed
curve of the third embodiment is shown in FIG. 56(d). In the third
embodiment, wind also blows from the center portion of the axial
flow fan to the air blow side. As shown in FIG. 22, the first
embodiment of the air intake regulating plate 105 is an improvement
of the third embodiment. In the first embodiment, so as to easily
inject and mold plastics, air blow openings 116, 117, and 118
facing three liquid crystal panel blocks 115 are formed below these
blocks 115 on an upper surface 66a of a cylindrical member. A
plurality of branch walls 119 made of curved and straight portions
are disposed so that air flows through the liquid crystal light
valve 7c (7a, and 7b) equally upwardly along the space of the
polarizing plates 112. In addition, to activate the air flow of the
entire flow paths in the case, a plurality of air blow openings 120
are formed on the side of the cylindrical member.
In FIG. 14, the optical unit 75 is a block for separating and
mixing light of a light source. Reference numeral 121 an upper
light guide which is made as a metal plate and is in a box shape. A
light entrance opening 122 at which light enters and a light emit
opening 123 from which light is emitted are open. Reference numeral
124 is an air blow opening of three air paths formed on the top 125
of the upper light guide 121. Reference numeral 126 is a lower
light guide which is substantially of box shape. The upper light
guide 121 accommodates optical parts in such a way that the upper
light guide 121 covers the lower light guide 126. Column members
are disposed midway between the upper light guide 121 and the lower
light guide 126. In addition, the upper light guide 121 and the
lower light guide 126 are secured by screws. As a result, the
strength of the optical unit 75 becomes high. Reference numeral 127
is a prepolarizer block where a prepolarizer 128 made of a
plurality of glass plates arranged in a V shape is clamped with a
glass fixing plate 129, a support rubber 130, and a glass support
plate 131. A UV and IR filter portion 132 is adhered to the glass
support plate 131 with a double-sided adhesive tape. The
prepolarizer block 127 is mounted at the position of the light
entrance opening 122 of the optical unit 75. In this blocked
construction, the length of the optical paths in the optical unit
75 is shortened and the shock resistance thereof is improved.
Next, optical pants accommodated in the optical unit will be
described. The optical unit has three blocks, each of which
contains the prepolarizer 128, the UV and IR filter portion 132,
and the liquid crystal light valve 110. The polarizing plates 112
are disposed before and after each liquid crystal light halve.
Thus, a total of six polarizing plates 112 are disposed in the
three blocks. Reference numerals 4a and 4b are mirrors. Reference
numerals 2, 3a, 3b, and 5 are dichroic mirrors. Reference numeral
135 is a condenser lens. These optical parts are fixed to plate
shape fixing members. These fixing members are fixed to the inside
of the optical unit 75. As described above, the liquid crystal
light valves 7a, 7b, and 7c, and the polarizing plates 112 are
grouped into three liquid crystal light valve blocks 115, each of
which has an adjustment mechanism.
The projection lens unit 9 is fixed in accordance with the light
emitting opening 136 of the lower light guide 126.
FIGS. 23 to 26 show the construction of the lower light guide 126.
FIG. 23 is a plan view of the lower light guide 126. FIG. 24 is a
rear view of the lower light guide 126. FIG. 25 is a side view of
the lower light guide 126. FIG. 26 is a front view of the lower
light guide 126. Reference numeral 137 is an upper air blow opening
according to the air flow path of the air blow opening of the inlet
air regulating plate 105. Reference numeral 138 is an air blow
opening. This air blow opening 138 contributes to reducing the
weight of the lower light guide 126. Reference numeral 139 is an
air flow path guide. As shown in FIG. 27, the air flow path guide
139 is a wall which is bent at 90.degree. so as to guide cooling
air to the liquid crystal light valve 7c, (7a, and 7b) and the
polarizing plates 112 through the air intake opening 140.
Reference numeral 141 is an exhaust fan fixing plate. As shown in
FIGS. 28, 29, 30, and 36, the exhaust fan fixing plate 141 has
skirt-shaped air inlet guides 142 on the top, the right, and the
left thereof so as to suppress drawing air from the side of the air
intake opening of the exhaust fan 143 and to preferentially cool
heated members on the entire surface of the air intake opening in
front of the air blow opening of the exhaust fan 143.
As shown in FIGS. 28 and 34, a space 144 is formed in the vicinity
of the lamp. By disposing the lamp in the vicinity of the air
intake opening of the exhaust fan 143f the lamp and the highly
heated portion in the vicinity thereof can be directly and
effectively cooled.
In the conventional liquid crystal projectors, there is a problem
where dust and rubbish are attracted from the opening in the front
of the projection lens 9. To solve this problem, a side air blow
opening of the air intake regulating plate 105 is rotated
clockwise. The air from the rotating air blow opening strikes
against the upper wall on the right of the lower light guide 126
and thereby the wind is directed toward the window of the
projection lens. In addition, a branching plate 145 shown in FIG.
14 is disposed so as to prevent influence of the attracting force
of the exhaust fan 14S. Thus, the amount of blow air the front air
exhaust opening becomes low. As a result, dust and rubbish are not
attracted. The branching plate 145 is made of a thin plastic plate.
The branching plate 145 is substantially of a rectangular shape.
Part of the plate 145 is bent at 90.degree. and adhered to flat
surfaces of the base plate 90 and the lamp stabilizer 96 with a
double-sided adhesive tape.
Reference numeral 146 is a lamp fan block. The lamp fan block 146
is formed by winding a metal plate around the circumference of a
lamp fan 147. One side of the lamp fan block 146 is screwed to a
lamp fan fixing plate 149 which forms an air blow opening rotated
at 90.degree. from an air blow opening of the lamp fan 147. On a
side of a window frame 150 in the front of the air blow opening of
the lamp fan 147, the lamp fan fixing plate 149 is fixed so as to
form the lamp fan block 146. The lamp fan block 146 is fixed on a
side of the light entrance opening 122 of the upper light guide.
The window frame 150 prevents light from the lamp from leaking out
by using a surface of a front portion 151 and a 90.degree. bend
portion 152 as shown in FIG. 33. In addition, the window frame 150
allows air of the lamp fan 147 to pass through from a window frame
hole 153.
Next, an inner housing block 154 of the lamp housing unit 91 will
be described. As shown in FIGS. 34 to 47, reference numeral 1 is a
lamp as a light source. In the lamp 1, a lighting tube 156 is fixed
to a reflector 157. The lamp 1 is positioned and fixed to an
L-shaped lamp fixing plate 158 with a lamp spring 159. A lamp male
connector 160 is positioned and screwed to an L-shaped lower cut
portion of the lamp fixing plate 158. The lamp fixing plate 158 is
surrounded by a lamp inner housing member 161 and screwed to the
lamp fixing plate 158. The inner housing member 161 has a handle
162. In the rear of the lamp 1, a rear electrode plate 163 and a
side electrode plate are disposed. Both the electrodes and the lamp
male connector 160 are connected to electric wires 164. These
electric wires 164 have a high heat resistance. In addition to the
electric wires, respective electric wire connecting portions of the
lamp male connector 160 are coated with highly insulated shrinkable
tubes 165. On a side of the inner housing member 161, a vent hole
portion 166 for cooling is disposed. In the front of the lamp
lighting tube 156, a heat insulating film 167 is coated. In the
figure, reference numeral 168 is a control portion. Reference
numeral 169 is a hole for providing an insulating space. Reference
numeral 170 is a fixing portion of the lamp inner housing block
154. Reference numeral 171 is a grille portion for providing an
insulation space. Reference numeral 172 is an E ring by which the
lamp can be replaced without removing screws from the inner
housing. Reference numeral 173 is a slide guide portion. Reference
numeral 174 is an upper-lower positioning portion. Reference
numeral 175 is a vertical positioning portion. Reference numeral
176 is a left-right positioning portion. Reference 177 is an
opening portion.
The holes of vent hole portion 166 are formed at a pitch different
from those of the vent holes of the outer housing member 178 and
grille windows 180 so that light does not leak out to the
outside.
Next, a lamp outer housing block 181 of the lamp housing unit 91
will be described.
The front of the outer housing member 178 is an entrance opening of
the inner housing block 154. In the front, there are screw holes
for fixing the inner housing and two fixing tables 182 where three
portions of the lamp outer housing block 181 are cut and raised. On
the left side of the lamp outer housing block 181, there are grille
windows 180 for downward ventilation and vent holes 179. On the
right side of the lamp outer housing block 181, there are grille
windows 180 for upward ventilation and vent holes 179. At the top
of the lamp outer housing block 181, there is a grille portion 178a
for providing an insulation distance, left and right positioning
holes 183 of the lamp fixing plate 158, screw holes 184 for fixing
an overheat protection safety switch, and a screw hole 185 for
fixing a thermistor. In the rear of the lamp outer housing block
181, there is a vertical air flow control portion 186 and a
horizontal air flow control portion 187 for allowing wind to blow
against the surface of the lamp lighting tube 156 and the hottest
portion of the heat insulation film. These portions 186 and 187 are
formed by cutting and raising the lamp outer housing block 181. In
addition, at a center position of the rear of the lamp outer
housing block 181, a light emitting opening 188 is formed. At a
lower position of the rear of the lamp outer housing block 181, a
connector window 189 is formed. In the rear of the lamp outer
housing block 181, a rear member 190 with high vertical accuracy
and upper-lower positioning portions 191 are formed. Moreover, in
the rear of the lamp outer housing block 181, there are fixing
holes 192 for fixing the lamp outer housing block 181 to the base
plate 90 and positioning holes 193 thereof.
Reference numeral 194 is a lamp connector plate for connecting a
lamp female connector 196 to a connector fixing portion 195 through
a connector bush 197.
There is a space between the connector bush 197 and the connector
fixing hole 198. This space accommodates axial deviation of the
connector. A lamp connector plate upper member 199 insulates the
connector from light. In addition, the upper member 199 shields the
connector from EMI. Reference numeral 200 is a ground terminal
fixing portion. The lamp female connector 196 has a guide slope for
smooth connection.
When the inner housing block 154 is inserted into the outer housing
181, the vertical positioning portions 175 of the inner housing 154
are contacted with the rear member 190 which is the reference
surface of the outer housing 154. In addition, the upper-lower and
left-right positioning portions 174 and 176 are contacted in
positions. As a result, the inner housing block 154 is correctly
positioned.
A second embodiment of the case 70 will be described with reference
to FIGS. 52 and 53.
Reference numeral 201 is an exhaust air drawing protection wall.
When the liquid crystal projector is installed in such a way that
the rear of the case of the projector contacts a wall, this
protection wall 201 prevents the air intake opening from drawing
exhausted warm air through the space between a case bottom 202 and
the floor.
Next, a third embodiment of the case 70 will be described with
reference to FIGS. 54 and 55.
In this embodiment, the strength of the exhaust air drawing
protection wall 201 of the second embodiment is improved so that it
can have the function of a foot.
As described above, fresh air drawn by the air intake fan 105 cools
the liquid crystal light valves 7a, 7b, and 7c. Thereafter, the air
flows from the opening portion 101 of the drive board unit 100
upwardly. Next, the air merges with air coming from the side
openings 120 of the air intake regulating plate 105 in the vertical
direction and then cools the lamp stabilizer unit 96 and the power
unit 95. Thereafter, the air cook the lamp 1. Finally, the air is
exhausted to the outside by the lamp fan 147 and the air exhaust
fan 143.
In the above-mentioned construction, the optical unit, which
comprises the lamp housing unit, the liquid crystal light valves,
the mirrors, the dichroic mirrors, and the projection lens, the air
intake fan, the lamp fan, the exhaust fan, and so forth are
compactly accommodated in a rectangular parallelepiped case so that
an image mixed by at least three liquid crystal light valves for
forming color images is projected as a picture onto a screen by the
projection lens. In addition, with the air intake regulating plate
and the air branching plates, the air flow paths can be branched
and enlarged. Thus, the operability, durability, maintainability,
and environmental properties are improved.
FIGS. 57 and 58 show a cooling means of the lighting unit of the
liquid crystal projector. FIG. 57 is a view showing the
construction of the cooling means. The lamp 1 comprising a metal
halide lamp 156 and a lamp reflector 157 is fixed to a lamp fixing
plate 158 and accommodated in a lamp housing 207. A rear sealed
portion 208 of the metal halide lamp 156 is inserted into a lamp
fixing portion 209 of the lamp reflector 157 and then fixed with
cement or the like. By connecting a front electrode plate 210 and a
rear electrode plate 163 of the metal halide lamp to the lamp
stabilizer 96 disposed outside the lamp unit, the metal halide lamp
156 can be lit. As the cooling means, the air exhaust fan 143 which
is an axial flow fan having blades with an outer diameter equal to
or larger than the diameter of the opening portion of the lamp
reflector 157 is disposed near the lamp house 207. Thus, the air
exhaust fan 143 draws air through the inside of the lamp housing
207. On the sides of the lamp housing 207, there are air intake and
exhaust holes for cooling the lamp 1. Thus, air flows in the
directions of the arrow in the lamp housing 207. In addition, at a
position close to the lamp reflector opening portion 214, the lamp
fan 147 which is smaller than the diameter of the lamp reflector
opening portion 214 is disposed.
When an axial flow fan is used for the lamp fan 147, the wind is
widened in the air blow direction. In addition, since the wind is
twisted in the rotating direction of the fan, the wind also flows
to the region surrounded by the lamp reflector 157.
FIG. 58 is a side view of the cooling means. In the front of the
air blow side of the lamp fan 147, an air regulating plate 216 is
disposed. The air regulating plate 216 can accurately guide cold
air directly to the surfaces of the lighting robe 156 and the front
sealed portion 156a in the direction of the arrows.
It should be noted that the lamp fan 147 can be a scirocco fan or a
cross flow fan. In addition, the lamp fan 147 can be installed at
an angle. Moreover, the blowing direction of the lamp fan 147 can
be changed in the range of the conventional blowing direction
.+-.90.degree..
Further, the regulating plate 216 can be disposed in the lamp
housing 147 or midway between the lamp house 207 and the lamp fan
147.
In the above mentioned construction, after the metal halide lamp
156 is discharged and lit, the air exhaust fan 213 cools the entire
lamp 1. In addition, the lamp fan 147 and the regulating plate 216
produce air flows on the surfaces and peripheries of the lighting
tube 156 and the front sealed portion 156a, thereby improving the
cooling effect. In other words, the lamp fan 147 draws fresh air
and causes wind to blow against the lamp reflector opening portion
214. Thus, an air flow can be positively produced in the region
surrounded by the reflection surface of the lamp reflector 157.
Thus, by decreasing the surface temperature of the quartz glass of
the lighting tube 156.degree. to 900.degree. C. or below, the
phenomenon where only the upper portion becomes opaque can be
prevented. As a result, the differences of brightness and
temperatures at upper and lower portions of the lighting tube 156
can be reduced. In addition, when the temperature of the front
sealed portion 156a is decreased to 300.degree. C. or below, the
air insulation can be maintained for a long time. Thus, the life of
the lighting unit can be prolonged.
Thus, as the above-mentioned cooling means, by disposing another
lamp fan at a position adjacent to the reflector opening portion,
air flows effectively take place on the surface of the lighting
tube and in the front sealed portion in the region surrounded by
the reflection surface of the lamp reflector. Therefore, the
surface temperature of the quartz glass can be cooled to a required
temperature or below. As a result, the phenomenon where part of the
quartz glass becomes opaque does not take place. Consequently, the
optical properties such as brightness and color temperatures can be
stabilized. In addition, when the temperature of the front sealed
portion is decreased to the required temperature or below, the air
insulation of the metal halide lamp can be maintained for a long
time and thereby the life thereof can be prolonged. When this
lighting unit is used in the liquid crystal color projector,
projected pictures which are free of uneven intensity of
illumination and uneven colors can be accomplished. Moreover, in
comparison with the related art, a metal halide lamp with a long
life can be obtained.
INDUSTRIAL UTILIZATION
The present invention is suitable for a projection type liquid
crystal video projector which is small in size and light in weight,
free of uneven colors and deviation of pixels, and has high
brightness and high magnification.
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