U.S. patent number RE41,874 [Application Number 12/318,817] was granted by the patent office on 2010-10-26 for method of manufacturing reflective mirror, illumination device, and projector.
This patent grant is currently assigned to Seiko Epson Corporation. Invention is credited to Toshiaki Hashizume.
United States Patent |
RE41,874 |
Hashizume |
October 26, 2010 |
Method of manufacturing reflective mirror, illumination device, and
projector
Abstract
A reflective mirror manufacturing method for manufacturing a
reflective mirror used in an illumination device including an arc
tube including a light-emitting portion and a reflective mirror
including a reflective surface that reflects light from the
light-emitting portion in a predetermined direction, includes: a
first step of forming a tube by heating a tube including a material
of the reflective mirror, thereafter putting the tube in a form
block, applying internal pressure with an inert gas to cause a
center portion of the tube to expand, so that part of an inner
surface of the expanded center portion includes a shape
corresponding to the reflective surface of the reflective mirror; a
second step of cutting the tube at the center portion to form a
reflective mirror member; and a third step of forming a reflective
layer on an inner surface of the reflective mirror member.
Inventors: |
Hashizume; Toshiaki (Okaya,
JP) |
Assignee: |
Seiko Epson Corporation (Tokyo,
JP)
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Family
ID: |
34191056 |
Appl.
No.: |
12/318,817 |
Filed: |
January 8, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
10916603 |
Aug 12, 2004 |
07159990 |
Jan 9, 2007 |
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Foreign Application Priority Data
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Aug 18, 2003 [JP] |
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2003-294675 |
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Current U.S.
Class: |
353/98; 353/99;
445/26; 353/121; 362/263; 313/113 |
Current CPC
Class: |
G03B
21/2066 (20130101); C03B 23/07 (20130101); H04N
9/315 (20130101) |
Current International
Class: |
G03B
21/28 (20060101); G03B 21/00 (20060101); H01J
9/00 (20060101); H01J 5/16 (20060101); F21S
8/00 (20060101) |
Field of
Search: |
;353/98 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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A-52-22061 |
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Feb 1977 |
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JP |
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A-09-120067 |
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May 1977 |
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JP |
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A-55-101417 |
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Aug 1980 |
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JP |
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A-59-156927 |
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Sep 1984 |
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JP |
|
A-05-62595 |
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Mar 1993 |
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JP |
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A-06-339981 |
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Dec 1994 |
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JP |
|
A-08-281691 |
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Oct 1996 |
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JP |
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A-09-254271 |
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Sep 1997 |
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JP |
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A-11-143378 |
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May 1999 |
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JP |
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A-2000-173313 |
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Jun 2000 |
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JP |
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A-2000-298213 |
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Oct 2000 |
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JP |
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A-2000-347293 |
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Dec 2000 |
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JP |
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A-2002-90883 |
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Mar 2002 |
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JP |
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A-2002-154837 |
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May 2002 |
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JP |
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Primary Examiner: Koval; Melissa J
Attorney, Agent or Firm: Oliff & Berridge, PLC
Claims
The invention claimed is:
1. A .Iadd.method for manufacturing a .Iaddend.reflective mirror
.[.manufacturing method for manufacturing a reflective mirror.].
used in an illumination device including an arc tube
.[.including.]. .Iadd.having .Iaddend.a light-emitting portion and
a reflective mirror .[.including.]. .Iadd.having .Iaddend.a
reflective surface that reflects light from the light-emitting
portion in a predetermined direction, the method comprising: .[.a
first step of forming.]. .Iadd.heating .Iaddend.a tube .[.by
heating a tube including.]. .Iadd.comprising .Iaddend.a material of
the reflective mirror, thereafter putting the tube in a form block,
applying internal pressure with an inert gas to cause a center
portion of the tube to expand, so that part of an inner surface of
the expanded center portion includes a shape corresponding to the
reflective surface of the reflective mirror; .Iadd.the expanded
center portion being continuous with a part of a tube portion that
includes a shape corresponding to a fixing portion where the arc
tube is fixed to the reflective mirror; .Iaddend. .[.a second step
of.]. cutting the tube at the .Iadd.expanded .Iaddend.center
portion to form a reflective mirror member; and .[.a third step
of.]. forming a reflective layer on .[.an inner surface.].
.Iadd.the reflective surface .Iaddend.of the reflective mirror
member.
2. The .[.reflective mirror manufacturing method of.]. .Iadd.method
according to .Iaddend.claim 1, further .[.including.].
.Iadd.comprising.Iaddend.: .[.in the first step,.]. forming the
tube so that it has a shape where two reflective mirror members
mutually face each other, .Iadd.when the center portion of the tube
expands by applying internal pressure with an inert gas,
.Iaddend.and .[.in the second step,.]. forming the two reflective
mirror members.Iadd., when the tube cutting at the expanded center
portion.Iaddend..
3. The .[.reflective mirror manufacturing method of.]. .Iadd.method
according to .Iaddend.claim 1, the reflective mirror being a
reflective mirror disposed with an effective reflective surface in
a range from a portion of at least 40.degree. with respect to an
optical axis of the reflective mirror, using a light emission
center of the light-emitting portion as a reference, to an open end
portion of the reflective mirror.
4. An illumination device, comprising: an arc tube including a
light-emitting portion; and a reflector including a reflective
surface without mold marks that reflects light from the
light-emitting portion in a predetermined direction, the reflector
being a reflector manufactured by a reflector manufacturing method
comprising: .[.a first step of forming.]. .Iadd.heating .Iaddend.a
tube .[.by heating a tube including.]. .Iadd.comprising .Iaddend.a
material of the reflector, thereafter putting the tube in a form
block, applying internal pressure with an inert gas to cause a
center portion of the tube to expand, so that part of an inner
surface of the expanded center portion includes a shape
corresponding to the reflective surface of the reflector; .Iadd.the
expanded center portion being continuous with a part of a tube
portion that includes a shape corresponding to a fixing portion
where the arc tube is fixed to the reflector; .Iaddend. .[.a second
step of.]. cutting the tube at the .Iadd.expanded .Iaddend.center
portion to form a reflector member; and .[.a third step of.].
forming a reflective layer on .[.an inner surface.]. .Iadd.the
reflective surface .Iaddend.of the reflector member.
5. A projector, comprising: .[.the.]. .Iadd.an
.Iaddend.illumination optical system including the illumination
device of claim 4; an electro-optical modulation device that
modulates light from the illumination optical system in accordance
with image information; and a projection optical system that
projects the light modulated by the electro-optical modulation
device.
6. The illumination device .[.of.]. .Iadd.according to
.Iaddend.claim 4, the reflector being a reflector manufactured by
the reflector manufacturing method where .[.in the first step,.].
forming the tube so that it has a shape where two reflector members
mutually face each other, .Iadd.when the center portion of the tube
expands by applying internal pressure with an inert gas,
.Iaddend.and .[.in the second step,.]. forming the two reflector
members.Iadd., when the tube cutting at the expanded center
portion.Iaddend..
7. A projector, comprising: an illumination optical system
including the illumination device of claim 6; an electro-optical
modulation device that modulates light from the illumination
optical system in accordance with image information; and a
projection optical system that projects the light modulated by the
electro-optical modulation device.
8. The illumination device .[.of.]. .Iadd.according to
.Iaddend.claim 4, the reflector being a reflector disposed with an
effective reflective surface in a range from a portion of at least
40.degree. with respect to an optical axis of the reflector, using
a light emission center of the light-emitting portion as a
reference, to an open end portion of the reflector.
9. A projector, comprising: an illumination optical system
including the illumination device of claim 8; an electro-optical
modulation device that modulates light from the illumination
optical system in accordance with image information; and a
projection optical system that projects the light modulated by the
electro-optical modulation device.
10. An illumination device, comprising: an arc tube including a
light-emitting portion; a reflector including a reflective surface
without mold marks that reflects light from the light-emitting
portion to an illuminated region; and an auxiliary mirror that is
disposed facing the reflector with the light-emitting portion
sandwiched therebetween, the auxiliary mirror including a
reflective surface without mold marks and which reflects part of
the light emitted from the light-emitting portion towards the
light-emitting portion, the auxiliary mirror being an auxiliary
mirror manufactured by an auxiliary mirror manufacturing method
.[.including.]. .Iadd.comprising.Iaddend.: .[.a first step of
forming.]. .Iadd.heating .Iaddend.a tube .[.by heating a tube
including.]. .Iadd.comprising .Iaddend.a material of the auxiliary
mirror, thereafter putting the tube in a form block, applying
internal pressure with an inert gas to cause a center portion of
the tube to expand, so that part of an inner surface of the
expanded center portion includes a shape corresponding to the
reflective surface of the auxiliary mirror, .Iadd.the expanded
center portion being continuous with a part of a tube portion that
includes a shape corresponding to a fixing portion where the arc
tube is fixed to the auxiliary mirror.Iaddend.; .[.a second step
of.]. cutting the tube at the .Iadd.expanded .Iaddend.center
portion to form an auxiliary mirror member; and .[.a third step
of.]. forming a reflective layer on .[.an inner surface.].
.Iadd.the reflective surface .Iaddend.of the auxiliary mirror
member.
11. A projector, comprising: an illumination optical system
including the illumination device of claim 10; an electro-optical
modulation device that modulates light from the illumination
optical system in accordance with image information; and a
projection optical system that projects the light modulated by the
electro-optical modulation device.
12. The illumination device .[.of.]. .Iadd.according to
.Iaddend.claim 10, the auxiliary mirror being an auxiliary mirror
manufactured by the auxiliary mirror manufacturing method where
.[.in the first step,.]. .Iadd.forming .Iaddend.the tube .[.is
formed.]. so that it has a shape where two auxiliary mirror members
mutually face each other, .Iadd.when the center portion of the tube
expands by applying internal pressure with an inert gas,
.Iaddend.and .[.in the second step,.]. .Iadd.forming .Iaddend.the
two auxiliary mirror members .[.are formed.]. .Iadd., when the tube
cutting at the expanded center portion.Iaddend..
13. A projector, comprising: an illumination optical system
including the illumination device of claim 12; an electro-optical
modulation device that modulates light from the illumination
optical system in accordance with image information; and a
projection optical system that projects the light modulated by the
electro-optical modulation device.
14. The illumination device .[.of.]. .Iadd.according to
.Iaddend.claim 10, the auxiliary mirror being an auxiliary mirror
disposed with an effective reflective surface in a range from a
portion of at least 40.degree. with respect to an optical axis of
the auxiliary mirror, using a light emission center of the
light-emitting portion as a reference, to an open end portion of
the auxiliary mirror.
15. A projector, .[.including.]. .Iadd.comprising.Iaddend.: an
illumination optical system including the illumination device of
claim 14; an electro-optical modulation device that modulates light
from the illumination optical system in accordance with image
information; and a projection optical system that projects the
light modulated by the electro-optical modulation device.
16. The illumination device .[.of.]. .Iadd.according to
.Iaddend.claim 10, the reflector being a reflector manufactured by
a reflector manufacturing method .[.including.].
.Iadd.comprising.Iaddend.: .[.a first step of forming a.].
.Iadd.heating a .Iaddend.tube .[.by heating a tube including.].
.Iadd.comprising .Iaddend.a material of the reflector, thereafter
putting the tube in a form block, applying internal pressure with
an inert gas to cause a center portion of the tube to expand, so
that part of an inner surface of the expanded center portion
includes a shape corresponding to the reflective surface of the
reflector.Iadd., the expanded center portion being continuous with
a part of a tube portion that includes a shape corresponding to a
fixing portion where the arc tube is fixed to the
reflector.Iaddend.; .[.a second step of.]. cutting the tube at the
.Iadd.expanded .Iaddend.center portion .Iadd.being continuous with
a part of a tube portion that includes a shape corresponding to a
fixing portion where the arc tube is fixed to the reflector;
cutting the tube at the expanded center portion .Iaddend.to form a
reflector member; and .[.a third step of.]. forming a reflective
layer on .[.an inner surface.]. .Iadd.the reflective surface
.Iaddend.of the reflector member.
17. A projector, comprising: an illumination optical system
including the illumination device of claim 16; an electro-optical
modulation device that modulates light from the illumination
optical system in accordance with image information; and a
projection optical system that projects the light modulated by the
electro-optical modulation device.
Description
BACKGROUND
Exemplary aspects of the present invention relate to a method of
manufacturing reflective mirror, an illumination device and a
projector.
Related art projectors realize image display by modulating, in
accordance with image information using a liquid crystal panel,
illumination light emitted from an illumination optical system and
projecting the modulated light onto a projection surface, such as a
screen.
The illumination optical system is disposed with an arc tube
including a light-emitting portion and a reflector including a
reflective surface that reflects the light from the light-emitting
portion of the arc tube in a predetermined direction. It is
preferable for the illumination device to be able to use, as
effectively as possible, the light from the arc tube.
For this reason, a related art parabolic reflector including a
concave surface configured by a paraboloid of revolution is used as
the reflector. See JP-A-2000-298213. FIG. 4 is a schematic showing
an example of an optical system of a related art projector using
such a parabolic reflector. As shown in FIG. 4, a parabolic
reflector 930A is used, and by disposing a light emission center of
an arc tube 920A in the focal position of the parabolic reflector
930A, the light emitted from the arc tube 920A can be made into
substantially parallel light. Thus, the light emitted from the arc
tube can be used effectively.
An ellipsoidal reflector including a concave surface configured by
an ellipsoid of revolution is also used as the reflector. See
JP-A-2002-90883. FIG. 5 is a schematic showing an example of an
optical system of a projector 900B using such an ellipsoidal
reflector. As shown in FIG. 5, an ellipsoidal reflector 930B is
used, and by disposing the light emission center of an arc tube
920B in one focal point (first focal point) of the ellipsoidal
reflector 930B, the light emitted from the arc tube 920B can be
effectively focused at another focal point (second focal point) of
the ellipsoidal reflector 930B. Thus, the light emitted from the
arc tube can be used effectively.
FIG. 6 is a schematic showing another example of an optical system
901C of a projector 900C using such an ellipsoidal mirror. As shown
in FIG. 6, an ellipsoidal reflector 930C is used, and by disposing
the light emission center of an arc tube 920C in one focal point
(first focal point) of the ellipsoidal reflector 930C and disposing
a parallelizing lens 945 to make parallel the emission light from
the ellipsoidal reflector 930C, the light emitted from the arc tube
920C can be made into substantially parallel light. Thus, the light
emitted from the arc tube can be used effectively. See
JP-A-2000-347293.
Such reflectors are usually manufactured by press molding. FIG. 7
is a schematic showing a related art reflector manufacturing method
for explanation.
In the related art reflector manufacturing method, as shown in FIG.
7, a reflector 930D is molded using a form block 930M disposed with
a lower mold 931 including a concave cavity, a press mold 932
disposed so as to surround the periphery of the cavity of the lower
mold 931, and a core 933 that slides the inside of a slide-use
opening of the press mold 932 towards the inside of the cavity of
the lower mold 931. Specifically, a softened glass material is
supplied to the inside of the cavity of the lower mold 931, the
glass material is pressurized by sliding the core 933, and the
glass material spreads and fills the inside of the form block 930M.
Thus, reference surfaces 937 and 939 are formed by the press mold
932, and a reflective surface 935 is formed by the core 933.
SUMMARY
However, in this related art reflector manufacturing method, when
the continuous production quantity increases, the surface of the
form block is abraded and the reflector material adheres to the
surface of the form block, whereby the state of the surface of the
form block deteriorates. For this reason, there have been problems
that the characteristics of the reflective surface of the reflector
to be manufactured deteriorate, the light use efficiency drops and
the manufacturing cost rises.
Among illumination devices, there is an illumination device that
includes, in addition to an arc tube 920E and a reflector 930E, an
auxiliary mirror 940 that reflects, towards the arc tube 920E,
light emitted from the arc tube 920E to an illuminated region. See
JP-A-11-143378. FIG. 8 is a schematic showing an illumination
device 910E including such an auxiliary mirror 940. As shown in
FIG. 8, an auxiliary mirror 940 is also ordinarily manufactured by
press molding.
For this reason, even with respect to the auxiliary mirror 940,
when the continuous production quantity increases, the surface of
the form block is abraded and the auxiliary mirror material adheres
to the surface of the form block, whereby the state of the surface
of the form block deteriorates. For this reason, there have been
problems that the characteristics of the reflective surface of the
auxiliary mirror to be manufactured deteriorates, the light use
efficiency drops and the manufacturing cost rises.
Thus, exemplary aspects of the present invention have been made in
order to address and/or eliminate the above-described and/or other
problems, and provides a reflective mirror manufacturing method for
manufacturing a reflective mirror, such as a reflector and an
auxiliary mirror, so that even if the continuous production
quantity increases, the characteristics of the reflective surface
of the reflective mirror to be manufactured do not deteriorate, the
light use efficiency does not drop and the manufacturing cost does
not rise.
Exemplary aspects of the present invention also provide, at an
inexpensive manufacturing cost, an illumination device and a
projector including an excellent reflective mirror whose light use
efficiency is high.
Exemplary aspects of the present invention provide a reflective
mirror manufacturing method for manufacturing a reflective mirror
used in an illumination device including an arc tube including a
light-emitting portion and a reflective mirror including a
reflective surface that reflects light from the light-emitting
portion in a predetermined direction. The method includes: a first
step of forming a tube by heating a tube consisting of a material
of the reflective mirror, thereafter putting the tube in a form
block, applying internal pressure with an inert gas to cause a
center portion of the tube to expand, so that part of an inner
surface of the expanded center portion includes a shape
corresponding to the reflective surface of the reflective mirror; a
second step of cutting the tube at the center portion to form a
reflective mirror member; and a third step of forming a reflective
layer on an inner surface of the reflective mirror member.
For this reason, according to the reflective mirror manufacturing
method of an exemplary aspect of the invention, a form block to
form the reflective surface of the reflective mirror becomes
unnecessary because the tube is formed by applying internal
pressure with an inert gas to cause a center portion of the tube to
expand, so that the tube has a shape corresponding to the
reflective surface of the reflective mirror. As a result, even if
the continuous production quantity of the reflective mirror
increases, the situation where the surface of the form block is
abraded and the reflective mirror material adheres to the surface
of the form block is reduced or eliminated. For this reason, even
if the continuous production quantity of the reflective mirror
increases, the situation where the state of the surface of the form
block deteriorates is eliminated, and the situation where the
characteristics of the reflective surface of the reflective mirror
to be manufactured deteriorate, the light use efficiency drops and
the manufacturing cost rises is reduced or eliminated. Thus, it
becomes possible to manufacture, at an inexpensive manufacturing
cost, a reflective mirror whose light use efficiency is high.
Also, according to the reflective mirror manufacturing method of an
exemplary aspect of the invention, because internal pressure is
applied with an inert gas to cause the center portion of the tube
to expand, so that a tube is formed having a shape corresponding to
the reflective surface of the reflective mirror, the inner surface
of the reflective mirror member contacts only the inert gas. Thus,
a smooth reflective surface, whose surface roughness is extremely
small, can be obtained as the reflective surface of the reflective
mirror.
For this reason, according to the reflective mirror manufacturing
method of an exemplary aspect of the invention, it becomes possible
to manufacture, at an inexpensive manufacturing cost, a smooth
reflective mirror whose surface roughness is extremely small and
whose light use efficiency is high.
Also, according to the reflective mirror manufacturing method of an
exemplary aspect of the invention, because that which contacts the
form block is the outer surface of the reflective mirror member,
affects such as mold marks do not appear in the reflective surface
of the reflective mirror. Thus, there is also the effect that a
reflective mirror having characteristics that are stable from the
initial manufacture to the end of the mold life can be
manufactured.
In the reflective mirror manufacturing method of an exemplary
aspect of the invention, in the first step, the tube may be molded
to have a shape where two reflective mirror members mutually face
each other, and in the second step, the two reflective mirror
members may be formed.
By configuring an exemplary aspect of the invention in this manner,
it becomes possible to form two reflective mirrors from one tube,
and it becomes possible to further reduce the manufacturing cost of
the reflective mirror.
In this case, it is also easy to make the two reflective mirrors
have exactly the same shape, so that in this case, it becomes
possible to further reduce the manufacturing cost.
In the reflective mirror manufacturing method of an exemplary
aspect of the invention, the reflective mirror may be a reflective
mirror disposed with an effective reflective surface in a range
from a portion of at least 40.degree. with respect to an optical
axis of the reflective mirror, using a light emission center of the
light-emitting portion as a reference, to an open end portion of
the reflective mirror.
Usually, arc tubes, such as high-pressure mercury lamps and metal
halide lamps include a light distribution characteristic such that
the brightness of the light, emitted in a range of 40.degree. to
140.degree. with respect to an extension-direction axis of seal
portions extending from both ends of the arc tube, becomes
relatively high. Also, in illumination devices, usually the optical
axis of the reflective mirror, such as a reflector or auxiliary
mirror, coincides with the extension-direction axis of the seal
portions of the arc tube. For this reason, according to the
reflective mirror manufacturing method of an exemplary aspect of
the invention, because a reflective mirror is manufactured that has
an effective reflective surface in a range from a portion of at
least 40.degree. with respect to the optical axis of the reflective
mirror, using the light emission center of the light-emitting
portion as a reference, to an open end portion of the reflective
mirror, the reflective mirror can be made into a reflective mirror
having a reflectance characteristic matching the light distribution
characteristic of the arc tube, and the use efficiency of the light
emitted from the arc tube can be raised.
Exemplary aspects of the invention also provide an illumination
device including an arc tube including a light-emitting portion and
a reflector that reflects light from the light-emitting portion to
an illuminated region. The reflector is a reflective mirror
manufactured by the reflective mirror manufacturing method of an
exemplary aspect of the invention.
For this reason, according to the illumination device of an
exemplary aspect of the invention, as described above, the
illumination device is inexpensive and has a light use efficiency
that is high because the illumination device includes the reflector
that is inexpensive and has a light use efficiency that is
high.
Exemplary aspects of the invention also provide an illumination
device including an arc tube including a light-emitting portion, a
reflector that reflects light from the light-emitting portion to an
illuminated region, and an auxiliary mirror that is disposed facing
the reflector with the light-emitting portion sandwiched
therebetween and which reflects part of the light emitted from the
light-emitting portion towards the light-emitting portion. The
auxiliary mirror is a reflective mirror manufactured by the
reflective mirror manufacturing method of an exemplary aspect of
the invention.
For this reason, according to the illumination device of an
exemplary aspect of the invention, as described above, the
illumination device is inexpensive and has a light use efficiency
that is high because the illumination device includes the auxiliary
mirror that is inexpensive and has a light use efficiency that is
high.
In the illumination device of an exemplary aspect of the invention,
in addition to the auxiliary mirror, the reflector may also be a
reflective mirror manufactured by the reflective mirror
manufacturing method of an exemplary aspect of the invention.
By configuring an exemplary aspect of the invention in this manner,
as described above, in addition to including the auxiliary mirror
that is inexpensive and has a light use efficiency that is high,
the illumination device is even more inexpensive and has a higher
light use efficiency because it includes a reflector that is
inexpensive and has a light use efficiency that is high.
Exemplary aspects of the invention also provide a projector
including: an illumination optical system including the
illumination device of an exemplary aspect of the invention; an
electro-optical modulation device that modulates light from the
illumination optical system in accordance with image information;
and a projection optical system that projects the light modulated
by the electro-optical modulation device.
For this reason, according to the projector of an exemplary aspect
of the invention, as described above, the projector is inexpensive
and has a light use efficiency that is high because the projector
is disposed with the illumination device that is inexpensive and
has a light use efficiency that is high.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1(a)-(b-2) are schematics for describing a reflector
manufacturing method pertaining to a first exemplary
embodiment;
FIGS. 2(a)-(b-4) are schematics for describing an auxiliary mirror
manufacturing method pertaining to a second exemplary
embodiment;
FIG. 3 is a schematic showing an optical system of a projector
pertaining to a third exemplary embodiment;
FIG. 4 is a schematic showing an example of an optical system of a
projector using a parabolic reflector;
FIG. 5 is a schematic showing an example of an optical system of a
projector using an ellipsoidal reflector;
FIG. 6 is a schematic showing another example of an optical system
of a projector using an ellipsoidal reflector;
FIG. 7 is a schematic showing a related art reflector manufacturing
method for explanation; and
FIG. 8 is a schematic showing an illumination device including an
auxiliary mirror.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
A method of manufacturing reflective mirror, an illumination device
and a projector of exemplary aspects of the present invention will
be described below on the basis of exemplary embodiments shown in
the drawings.
First Exemplary Embodiment
A first exemplary embodiment will be described using a reflector
manufacturing method as an example of the reflective mirror
manufacturing method of an exemplary aspect of the invention.
FIGS. 1(a)-(b-2) are schematics for describing the reflector
manufacturing method pertaining to the first exemplary embodiment.
FIG. 1(a) is a schematic for describing a reflector manufacturing
method (press molding) pertaining to a comparative example, and
FIG. 1(b) are diagrams for describing the reflector manufacturing
method (gas pressure molding) pertaining to the first exemplary
embodiment.
As shown in FIG. 1(a), the reflector manufacturing method (press
molding) pertaining to the comparative example includes conducting
press molding in a state where a reflector material W1 is put
between an upper mold MU30 and a lower mold ML30 having desired
shapes. For this reason, according to the reflector manufacturing
method pertaining to the comparative example, a high-precision
reflector can be relatively easily manufactured using the
high-precision upper mold MU30.
However, in the reflector manufacturing method pertaining to the
comparative example, when the continuous production quantity
increases, the surface of the upper mold MU30 is abraded and the
reflector material W1 adheres to the surface of the upper mold
MU30, whereby the state of the surface of the upper mold MU30
deteriorates. For this reason, there have been problems that the
characteristics of the reflective surface of the reflector to be
manufactured deteriorate and the light use efficiency drops.
The reflector manufacturing method (gas pressure molding)
pertaining to the first exemplary embodiment includes: a first
heating part of a tube T1 including a reflector material as shown
in FIG. 1(b-1), thereafter putting the tube T1 in a form block M30,
applying internal pressure with an inert gas to cause the center
portion of the tube T1 to expand as shown in FIG. 1(b-2) so that
part of the expanded inner surface includes a shape corresponding
to the reflective surface of the reflector to be manufactured; a
second step (not shown) of cutting the tube T1 at the center
portion and both ends to form a reflector member; and a third step
(not shown) of forming a reflective layer by forming a derivative
multilayer film, such as TiO.sub.2 and SiO.sub.2, on the inner
surface of the reflector material by vapor deposition, sputtering
or CVD.
For this reason, according to the reflector manufacturing method
pertaining to the first exemplary embodiment, because internal
pressure is applied with an inert gas to cause the center portion
of the tube to expand, so that a tube is formed having a shape
corresponding to the reflective surface of the reflector, a form
block to form the reflective surface of the reflector becomes
unnecessary. As a result, even if the continuous production
quantity of the reflector increases, the situation where the
surface of the form block is abraded and the reflector material
adheres to the surface of the form block is eliminated. For this
reason, even if the continuous production quantity of the reflector
increases, the situation where the state of the surface of the form
block deteriorates is eliminated, and the situation where the
characteristics of the reflective surface of the reflective mirror
to be manufactured deteriorate, the light use efficiency drops and
the manufacturing cost rises is eliminated. Thus, it becomes
possible to manufacture, at an inexpensive manufacturing cost, an
excellent reflective mirror whose light use efficiency is high.
Also, according to the reflector manufacturing method pertaining to
the first exemplary embodiment, because internal pressure is
applied with an inert gas to cause the center portion of the tube
to expand, so that a tube is formed having a shape corresponding to
the reflective surface of the reflector, the inner surface of the
reflector member contacts only the inert gas. Thus, a smooth
reflective surface whose surface roughness is extremely small can
be obtained as the reflective surface of the reflector.
For this reason, according to the reflector manufacturing method
pertaining to the first exemplary embodiment, it becomes possible
to manufacture, at an inexpensive manufacturing cost, a smooth
reflector whose surface roughness is extremely small and whose
light use efficiency is high.
Also, according to the reflector manufacturing method pertaining to
the first exemplary embodiment, because that which contacts the
form block is the outer surface of the reflector material, affects,
such as mold marks, do not appear in the reflective surface of the
reflector. Thus, there is also the effect that a reflector having
characteristics that are stable from the initial manufacture to the
end of the mold life can be manufactured.
In the reflector manufacturing method pertaining to the first
exemplary embodiment, in the first step, as shown in FIG. 1(b-2),
the tube T1 is molded to have a shape where two reflector members
mutually face each other, and in the second step, the two reflector
members are formed (not shown).
For this reason, it becomes possible to form two reflectors with
the same shape from one tube T1, and it becomes possible to further
reduce the manufacturing cost of the reflector.
In the reflector manufacturing method pertaining to the first
exemplary embodiment, the reflector is a reflector disposed with an
effective reflective surface in a range from a portion of at least
40.degree. with respect to the optical axis of the reflector, using
the light emission center of a light-emitting portion as a
reference, to an open end portion of the reflector.
Usually, arc tubes, such as high-pressure mercury lamps and metal
halide lamps, include a light distribution characteristic such that
the brightness of the light emitted in a range of 40.degree. to
140.degree. with respect to an extension-direction axis of seal
portions extending from both ends of the arc tube becomes
relatively high. Also, in illumination devices, usually the optical
axis of the reflector coincides with the extension-direction axis
of the seal portions of the arc tube. For this reason, according to
the reflector manufacturing method pertaining to the first
exemplary embodiment, because a reflector is manufactured that has
an effective reflective surface in a range from a portion of at
least 40.degree. with respect to the optical axis of the reflector,
using the light emission center of a light-emitting portion as a
reference, to an open end portion of the reflector, the reflector
can be made into a reflector having a reflectance characteristic
matching the light distribution characteristic of the arc tube, and
the use efficiency of the light emitted from the arc tube can be
raised.
Hard glass and quartz glass are suitable as the material of the
tube T1. Among these, quartz glass is particularly suitable. This
is because the coefficient of thermal expansion is low, and
therefore internal warps do not remain, so that annealing is not
necessary.
In the reflector manufacturing method pertaining to the first
exemplary embodiment, an excellent reflective surface is obtained
and the inner surface of the reflector can always maintain a high
reflectance because the inner surface of the glass tube,
excellently managed by the mold at the time of removal ordinarily,
becomes a departure shape.
In this manner, according to the reflector manufacturing method
pertaining to the first exemplary embodiment, it becomes possible
to manufacture, at an inexpensive manufacturing cost, a smooth
reflector whose surface roughness is extremely small and whose
light use efficiency is high.
For this reason, by using, in an illumination device or projector,
the reflector manufactured by the reflector manufacturing method
pertaining to the first exemplary embodiment, it becomes possible
to manufacture, at an inexpensive manufacturing cost, an excellent
illumination device and projector whose light use efficiency is
high.
Second Exemplary Embodiment
A second exemplary embodiment will be described using an auxiliary
mirror manufacturing method as an example of the reflective mirror
manufacturing method of an exemplary aspect of the invention.
FIGS. 2(a)-(b-4) are schematics for describing the auxiliary mirror
manufacturing method pertaining to the second exemplary embodiment.
FIG. 2(a) is schematic for describing an auxiliary mirror
manufacturing method (press molding) pertaining to a comparative
example, and FIGS. 2(b-1)-(b-4) are schematics for describing the
auxiliary mirror manufacturing method (gas pressure molding)
pertaining to the second exemplary embodiment.
As shown in FIG. 2(a), the auxiliary mirror manufacturing method
(press molding) pertaining to the comparative example includes
conducting press molding in a state where an auxiliary mirror
material W2 is put between an upper mold MU40 and a lower mold ML40
having desired shapes. For this reason, according to the auxiliary
mirror manufacturing method pertaining to the comparative example,
a high-precision auxiliary mirror can be relatively easily
manufactured using the high-precision upper mold MU40.
However, in the auxiliary mirror manufacturing method pertaining to
the comparative example, when the continuous production quantity
increases, the surface of the upper mold MU40 is abraded and the
auxiliary mirror material W2 adheres to the surface of the upper
mold MU40, whereby the state of the surface of the upper mold MU40
deteriorates. For this reason, there have been problems that the
characteristics of the reflective surface of the auxiliary mirror
to be manufactured deteriorate and the light use efficiency
drops.
The auxiliary mirror manufacturing method (gas pressure molding)
pertaining to the second exemplary embodiment includes: a first
step of heating part of a tube T2 including quartz glass, which is
an auxiliary mirror material, as shown in FIG. 2(b-1), thereafter
putting the tube T2 in a form block M40, applying internal pressure
with an inert gas to cause the center portion of the tube T2 to
expand as shown in FIG. 2(b-2) so that part of the expanded inner
surface includes a shape corresponding to the reflective surface of
the auxiliary mirror to be manufactured; a second step of cutting
the tube T2 at the center portion and both ends to form an
auxiliary mirror member as shown in FIG. 2(b-3); and a third step
(not shown) of forming a reflective layer by forming a derivative
multilayer film, such as TiO.sub.2 and SiO.sub.2, on the inner
surface of the auxiliary mirror member by vapor deposition,
sputtering or CVD.
FIG. 2(b-4) is a schematic where the auxiliary mirror manufactured
by the auxiliary mirror manufacturing method pertaining to the
second exemplary embodiment is fixed to an arc tube using an
adhesive. A ceramic adhesive that can withstand high temperatures
is used as the adhesive.
For this reason, according to the auxiliary mirror manufacturing
method pertaining to the second exemplary embodiment, because
internal pressure is applied with an inert gas to cause the center
portion of the tube to expand, so that a tube is formed having a
shape corresponding to the reflective surface of the auxiliary
mirror, a form block to form the reflective surface of the
auxiliary mirror becomes unnecessary. As a result, even if the
continuous production quantity of the auxiliary mirror increases,
the situation where the surface of the form block is abraded and
the auxiliary mirror material adheres to the surface of the form
block is eliminated. For this reason, even if the continuous
production quantity of the auxiliary mirror increases, the
situation where the state of the surface of the form block
deteriorates is eliminated, and the situation where the
characteristics of the reflective surface of the auxiliary mirror
to be manufactured deteriorate, the light use efficiency drops and
the manufacturing cost rise is eliminated. Thus, it becomes
possible to manufacture, at an inexpensive manufacturing cost, an
excellent auxiliary mirror whose light use efficiency is high.
Also, according to the auxiliary mirror manufacturing method
pertaining to the second exemplary embodiment, because internal
pressure is applied with an inert gas to cause the center portion
of the tube to expand, so that a tube is formed having a shape
corresponding to the reflective surface of the auxiliary mirror,
the inner surface of the auxiliary mirror member contacts only the
inert gas. Thus, a smooth reflective surface whose surface
roughness is extremely small can be obtained as the reflective
surface of the auxiliary mirror.
For this reason, according to the auxiliary mirror manufacturing
method pertaining to the second exemplary embodiment, it becomes
possible to manufacture, at an inexpensive manufacturing cost, a
smooth auxiliary mirror whose surface roughness is extremely small
and whose light use efficiency is high.
Also, according to the auxiliary mirror manufacturing method
pertaining to the second exemplary embodiment, because that which
contacts the form block is the outer surface of the auxiliary
mirror member, affects, such as mold marks, do not appear in the
reflective surface of the auxiliary member. Thus, there is also the
effect that an auxiliary mirror having characteristics that are
stable from the initial manufacture to the end of the mold life can
be manufactured.
Moreover, according to the auxiliary mirror manufacturing method
pertaining to the second exemplary embodiment, there are the
effects that the rate at which the reflection light from the
reflector is blocked can be minimized and the light use efficiency
can be further raised because the auxiliary mirror can be formed
extremely thinly. There is also the effect that the molding of the
portion fixing the auxiliary mirror to the arc tube also becomes
easy.
In the auxiliary mirror manufacturing method pertaining to the
second exemplary embodiment, in the first step, as shown in FIG.
2(b-2) and FIG. 2(b-3), the tube T2 is molded to have a shape where
two auxiliary mirror members mutually face each other, and in the
second step, two auxiliary mirror members 42 are formed.
For this reason, it becomes possible to form two auxiliary mirrors
40 with the same shape from one tube T2, and it becomes possible to
further reduce the manufacturing cost of the auxiliary mirror.
In the auxiliary mirror manufacturing method pertaining to the
second exemplary embodiment, the auxiliary mirror is an auxiliary
mirror disposed with an effective reflective surface in a range
from a portion of at least 40.degree. with respect to the optical
axis of the auxiliary member, using the light emission center of a
light-emitting portion as a reference, to an open end portion of
the auxiliary mirror.
Usually, arc tubes, such as high-pressure mercury lamps and metal
halide lamps, include a light distribution characteristic such that
the brightness of the light, emitted in a range of 40.degree. to
140.degree. with respect to an extension-direction axis of seal
portions extending from both ends of the arc tube, becomes
relatively high. Also, in illumination devices, usually the optical
axis of the reflector coincides with the extension-direction axis
of the seal portions of the arc tube. For this reason, according to
the auxiliary mirror manufacturing method pertaining to the second
exemplary embodiment, because an auxiliary mirror is manufactured
that has an effective reflective surface in a range from a portion
of at least 40.degree. with respect to the optical axis of the
auxiliary mirror, using the light emission center of a
light-emitting portion as a reference, to an open end portion of
the auxiliary mirror, the auxiliary mirror can be made into an
auxiliary mirror having a reflectance characteristic matching the
light distribution characteristic of the arc tube, and the use
efficiency of the light emitted from the arc tube can be
raised.
Hard glass and quartz glass are suitable as the material of the
tube T2. Among these, quartz glass is particularly suitable. This
is because the coefficient of thermal expansion is low. Therefore
internal warps do not remain, so that annealing is not
necessary.
In the auxiliary mirror manufacturing method pertaining to the
second exemplary embodiment, an excellent reflective surface is
obtained and the inner surface of the auxiliary mirror can always
maintain a high reflectance because the inner surface of the glass
tube excellently managed by the mold at the time of removal
ordinarily becomes a departure shape.
In this manner, according to the auxiliary mirror manufacturing
method pertaining to the second exemplary embodiment, it becomes
possible to manufacture, at an inexpensive manufacturing cost, a
smooth auxiliary mirror whose surface roughness is extremely small
and whose light use efficiency is high.
For this reason, by using, in an illumination device or projector,
the auxiliary mirror manufactured by the auxiliary mirror
manufacturing method pertaining to the second exemplary embodiment,
it becomes possible to manufacture, at an inexpensive manufacturing
cost, an excellent illumination device and projector whose light
use efficiency is high.
Third Exemplary Embodiment
In order to describe the effects when the reflective mirror
manufactured by the reflective mirror manufacturing method of an
exemplary aspect of the invention is used in an illumination device
and projector, a third exemplary embodiment will be described
using, as an example, a case where the reflector manufactured by
the reflector manufacturing method pertaining to the first
exemplary embodiment is used in a projector.
FIG. 3 is a schematic showing an optical system of a projector
pertaining to the third exemplary embodiment.
A projector 100 pertaining to the third exemplary embodiment is an
optical device where light beams emitted from a light source are
modulated in accordance with image information to form an optical
image, and the optical image is enlarged and projected onto a
screen SCR.
The projector 100 pertaining to the third exemplary embodiment
includes an optical system that is basically the same as the
optical system of a related art projector 900A shown in FIG. 4.
Specifically, as shown in FIG. 3, the projector 100 pertaining to
the third exemplary embodiment is disposed with an illumination
optical system 101, a color light separation optical system 200, a
relay optical system 240, an optical device 250 and a projection
optical system 420.
The illumination optical system 101 is disposed with an
illumination device 10A and an integrator optical system 60.
The illumination device 10A is disposed with a reflector 30A
manufactured by the reflector manufacturing method pertaining to
the first exemplary embodiment and an arc tube 20 including a light
emission center at a focal position of the reflector 30A.
The arc tube 20 includes a tube and seal portions that extend at
both sides of the tube. The tube is made of quartz glass formed in
a spherical shape and includes a pair of electrodes disposed inside
the tube, with the inside of the tube being filled with mercury, a
noble gas and a small amount of halogen.
The pair of electrodes inside the tube of the arc tube 20 is to
form an arc image. When a voltage is applied to the pair of
electrodes, a potential difference arises between the electrodes, a
discharge arises, and an arc image is generated.
Here, various kinds of arc tubes that emit light at a high
brightness can be used as the arc tube. For example, a metal halide
lamp, a high-pressure mercury lamp and a super high-pressure
mercury lamp can be used.
The reflector 30A includes a concave surface that aligns and emits,
in a constant direction, the light emitted from the arc tube 20.
The concave surface of the reflector 30A is formed as a cold mirror
that reflects visible light and transmits infrared light. The
optical axis of the reflector 30A coincides with an optical axis
30ax that is the central axis of the light beams emitted from the
illumination device 10A.
As described above, the illumination device 10A includes the arc
tube 20, which includes a light-emitting portion, and the reflector
30A, which reflects the light from the light-emitting portion to an
illuminated region, and the reflector 30A is a reflector
manufactured by the reflector manufacturing method pertaining to
the first exemplary embodiment. For this reason, as described
above, the illumination device is inexpensive and has a light use
efficiency that is high because the illumination device includes
the reflector that is inexpensive and has a light use efficiency
that is high.
The integrator optical system 60 is an optical system that
separates the light beams emitted from the illumination device 10A
into plural partial light beams to equalize the in-plane
illuminance of the illumination region. The integrator optical
system 60 is disposed with a first lens array 950, a second lens
array 960, a polarization conversion element 970, a superposition
lens 980 and a reflective mirror 955. An infrared reflective filter
80 is disposed on the optical path between the illumination device
10A and the first lens array 950.
The first lens array 950 includes a function as a light beam
separation optical element that separates the light beams emitted
from the illumination device 10A into plural partial light beams,
and is disposed with plural small lenses arranged in a matrix in a
plane intersecting the optical axis 30ax that is the central axis
of the light beams emitted from the illumination device 10A.
The second lens array 960 is an optical element that focuses the
plural partial light beams separated by the first lens array 950,
and similar to the first lens array 950, includes a configuration
disposed with plural small lenses arranged in a matrix in a plane
intersecting the optical axis 30ax.
The polarization conversion element 970 is a polarization
conversion element that emits, as substantially one kind of
linearly polarized light whose polarization direction has been
aligned, the polarization direction of the partial light beams
separated by the first lens array 950.
Although it is not shown, the polarization conversion element 970
is disposed with a configuration where polarization separation
films and reflection films disposed at an inclination with respect
to the optical axis 30ax are alternately arranged. The polarization
separation films transmit the polarized light beams of one of
P-polarized light beams and S-polarized light beams included in the
partial light beams, and reflect the other polarized light beams.
The other reflected polarized light beams are bent by the
reflective films and emitted in the emission direction of the one
polarized light beams, i.e., in the direction along the optical
axis 30ax. The polarization of either of the emitted polarized
light beams is converted by a phase plate disposed in the light
beam emission plane of the polarization conversion element 970. By
using the polarization conversion element 970, the use efficiency
of the light source light used by the optical device 250 can be
raised because the light beams emitted from the illumination device
10A can be aligned into polarized light beams of substantially one
direction.
The superposition lens 980 is an optical element that focuses the
plural partial light beams passing through the first lens array
950, the second lens array 960 and the polarization conversion
element 970, and superposes the plural partial light beams onto an
image forming region of three later-described liquid crystal
devices of the optical device 250.
The light emitted from the illumination optical system 101 is
emitted to the color separation optical system 200 and separated
into color light of the three colors of red (R), green (G) and blue
(B) in the color light separation optical system 200.
The color separation optical system 200 is disposed with two
dichroic mirrors 210 and 212 and a reflective mirror 220, and
includes the function of using the dichroic mirrors 210 and 211 to
separate, into color light of the three colors of red (R), green
(G) and blue (B), the plural partial light beams emitted from the
integrator optical system 60.
The dichroic mirrors 210 and 212 are optical elements where a
wavelength selection film that reflects light beams of a
predetermined wavelength region and transmits light beams of
another wavelength region are formed on a substrate. Additionally,
the dichroic mirror 210 disposed in the former stage of the optical
path is a mirror that transmits red light and reflects other color
light. Also, the dichroic mirror 212 disposed in the latter stage
of the optical path is a mirror that reflects green light and
transmits blue light.
The relay optical system 240 is disposed with an incident-side lens
262, a relay lens 264 and reflective mirrors 252 and 254, and
includes the function of guiding, to the optical device 250, the
blue light transmitted through the dichroic mirror 212 configuring
the color separation optical system 200. The reason the relay
optical system 240 is disposed in the optical path of the blue
light is to reduce or prevent a drop in the use efficiency of the
light resulting from diffusion of the light, because the optical
path length of the blue light is longer than the optical path
lengths of the other color light. Although the projector 100
pertaining to the third exemplary embodiment is configured in this
manner because the optical path length of the blue light is long, a
configuration is also conceivable where the optical path length of
the red light is lengthened and the relay optical system 240 is
used in the optical path of the red light.
After the red light separated by the dichroic mirror 210 is bent by
the reflective mirror 220, it is supplied to the optical device 250
via a field lens. Also, the green light separated by the dichroic
mirror 212 is supplied to the optical device 250 as is, via a field
lens. Moreover, the blue light is focused and bent by the lenses
262 and 264 and the reflective mirrors 252 and 254 configuring the
relay optical system 240, and is supplied to the optical device 250
via a field lens. The field lenses disposed in the former stage of
the optical path of each color light of the optical device 250 are
disposed in order to convert, to light beams substantially parallel
to the optical axis 30ax, the partial light beams emitted from the
illumination optical system 101.
The separated color light is modulated in correspondence to image
information in liquid crystal devices 300R, 300G and 300B.
The optical device 250 forms a color image by modulating the
incident light beams in accordance with image information. The
optical device 250 is disposed with the liquid crystal devices
300R, 300G and 300B (the liquid crystal device for the red light is
300R, the liquid crystal device for the green light is 300G, and
the liquid crystal device for the blue light is 300B) and a cross
dichroic prism 400. Here, each of the liquid crystal devices 300R,
300G and 300B is configured by a liquid crystal panel corresponding
to an electro-optical modulation device of an exemplary aspect of
the invention and polarization plates disposed at the
light-incident surface side and the light-emission surface side of
the liquid crystal panel. Light modulation of each color light made
incident is conducted by the incident-side polarization plates, the
liquid crystal panels and the emission-side polarization
plates.
The liquid crystal panels are panels where liquid crystal, which is
an electro-optical substance, is sealed in a pair of
light-transmissive glass substrates. For example, a polysilicon TFT
is used as a switching element to modulate, in accordance with an
applied image signal, the polarization direction of the polarized
light beams emitted from the incident-side polarization plates.
The color light beams modulated in the liquid crystal devices 300R,
300G and 300B are synthesized by the cross dichroic prism 400.
The cross dichroic prism 400 is an optical element that forms a
color image by synthesizing optical images modulated per color
light emitted from the emission-side polarization plates. The cross
dichroic prism 400 has a substantially square shape in plan view
where four right-angled prisms are adhered together, and derivative
multilayer films are formed at the substantially X-shaped interface
where the right-angled prisms are adhered together. One of the
substantially X-shaped derivative multilayer films reflects red
light, and the other derivative multilayer film reflects blue
light. The red light and the blue light are bent by these
derivative multilayer films and aligned with the traveling
direction of the green light, whereby the light beams of the three
colors are synthesized.
The color image synthesized by the cross dichroic prism 400 is
enlarged and projected onto the screen SCR by the projection
optical system 420. Thus, an image is displayed on the screen
SCR.
As described above, the projector 100 pertaining to the third
exemplary embodiment is disposed with the illumination optical
system 101 including the illumination device 10A, the liquid
crystal devices 300R, 300G and 300B that modulate the light from
the illumination optical system 101 in accordance with image
information, and the projection optical system 420 that projects
the light modulated by the liquid crystal devices 300R, 300G and
300B.
For this reason, according to the projector 100 pertaining to the
third exemplary embodiment, as described above, the projector is
inexpensive and has a light use efficiency that is high because the
projector 100 is disposed with the illumination device 10A that is
inexpensive and has a light use efficiency that is high.
The projector 100 pertaining to the third exemplary embodiment uses
the illumination optical system 101 disposed with the integrator
optical system 60 and the illumination device 10A including the
reflector 30A manufactured by the reflector manufacturing method
pertaining to the first exemplary embodiment. But the projector 100
can also use an illumination optical system 901B disposed with an
illumination device 910B including an ellipsoidal reflector 930B
including a concave surface configured by an ellipsoid of
revolution as shown in FIG. 5 and an integrator optical system
including an integrator rod 990. In a case where the illumination
optical system 901B is used in the projector, similar to the case
of the projector 100 pertaining to the third exemplary embodiment,
the projector can be configured to be an inexpensive projector and
have a light use efficiency that is high by using, in lieu of the
ellipsoidal reflector 930B, the reflector manufactured by the
reflector manufacturing method pertaining to the first exemplary
embodiment.
Also, the projector 100 pertaining to the third exemplary
embodiment used the illumination device 10A including the reflector
30A manufactured by the reflector manufacturing method pertaining
to the first exemplary embodiment. But the projector can also use
an illumination device 910E including an auxiliary mirror 940 and
an ellipsoidal reflector 930E including a concave surface
configured by an ellipsoid of revolution as shown in FIG. 8. In a
case where the illumination device 910E is used in the projector,
similar to the case of the projector 100 pertaining to the third
exemplary embodiment, the projector can be configured to be an
inexpensive projector and have a light use efficiency that is high
by using, in lieu of the auxiliary mirror 940, the auxiliary mirror
40 (see FIG. 2(b-4)) manufactured by the auxiliary mirror
manufacturing method pertaining to the second exemplary embodiment.
In this case, the projector can be configured to be an inexpensive
projector and have a light use efficiency that is high by using, in
lieu of the ellipsoidal reflector 910E, the reflector manufactured
by the reflector manufacturing method pertaining to the first
exemplary embodiment. In an illumination device including such an
auxiliary mirror, because the light emitted to the illuminated
region from the light-emitting portion of the arc tube is reflected
towards the reflector by the auxiliary mirror, it is not necessary
to set the size of the reflector to a size that covers the
illuminated region end portion of the arc tube, and the reflector
can be made compact. As a result, the illumination device can be
made compact.
A method of manufacturing reflective mirror, an illumination device
and a projector of an exemplary aspect of the invention have been
described on the basis of the preceding embodiments. But the
present invention is not limited to these exemplary embodiments. It
is possible to implement the invention in various kinds of modes
within a range that does not deviate from the gist thereof. For
example, the following modifications are also possible.
The illumination device described in the first exemplary embodiment
is an illumination device including the reflector manufactured by
gas pressure molding, and the illumination device described in the
second exemplary embodiment is an illumination device including an
auxiliary mirror manufactured by gas pressure molding, but the
invention is not limited thereto. The illumination device of an
exemplary aspect of the invention may also be an illumination
device including, in addition to an auxiliary mirror manufactured
by gas pressure molding, a reflector manufactured by gas pressure
molding.
In the preceding exemplary embodiments, an illumination device
disposed with the reflector manufactured by the reflector
manufacturing method pertaining to the first exemplary embodiment
and/or the auxiliary mirror manufactured by the auxiliary mirror
manufacturing method pertaining to the second exemplary embodiment
was disposed in a projector, but the invention is not limited
thereto. The illumination device may also be disposed in another
optical device.
In the projector pertaining to the third exemplary embodiment, a
case was described where an illumination device disposed with the
reflector manufactured by the reflector manufacturing method
pertaining to the first exemplary embodiment and/or the auxiliary
mirror manufactured by the auxiliary mirror manufacturing method
pertaining to the second exemplary embodiment was used in a front
type projector that projects a projection image from the observing
side, but the invention is also applicable to a rear type projector
that projects a projection image from the side opposite from the
observing side.
In the projector pertaining to the third exemplary embodiment, a
projector using the three liquid crystal devices 300R, 300G and
300B was described as an example, but the invention is also
applicable to a projector disposed with one, two, or four or more
liquid crystal devices.
In the projector pertaining to the third exemplary embodiment, a
case was described where the illumination device of an exemplary
aspect of the invention was applied to a transmissive type
reflector. But it is also possible to apply the invention to a
reflective type projector. Here, "transmissive type" means a type
where an electro-optical modulation device serving as light
modulating means transmits light, such as in a transmissive type
liquid crystal device. "Reflective type" means a type where an
electro-optical modulation device serving as light modulating means
reflects light, such as in a reflective type liquid crystal device.
Even in a case where the invention is applied to a reflective type
projector, effects that are substantially the same as those of a
transmissive type projector can be obtained.
The projector pertaining to the third exemplary embodiment uses the
liquid crystal devices 300R, 300G and 300B as electro-optical
modulation devices, but the invention is not limited thereto. It
suffices as long as the electro-optical modulation device is one
that usually modulates incident light in accordance with image
information, and a micromirror type optical modulation device may
be used. For example, a DMD (digital micromirror device) can be
used as the micromirror type optical modulation device.
* * * * *