U.S. patent application number 13/154877 was filed with the patent office on 2011-09-29 for projection display.
Invention is credited to Koji HIRATA, Masahiko Yatsu.
Application Number | 20110234982 13/154877 |
Document ID | / |
Family ID | 37721659 |
Filed Date | 2011-09-29 |
United States Patent
Application |
20110234982 |
Kind Code |
A1 |
HIRATA; Koji ; et
al. |
September 29, 2011 |
PROJECTION DISPLAY
Abstract
A projection type image display apparatus is provided which
includes a housing to hold an optical system including
multi-lenses, a polarized-light conversion element and a color
separation portion. The housing operates to provide an optical path
between a light source, located outside the housing, and
penetration-type image display elements and an optical synthesizing
portion also located outside of the housing.
Inventors: |
HIRATA; Koji; (Yokohama,
JP) ; Yatsu; Masahiko; (Fujisawa, JP) |
Family ID: |
37721659 |
Appl. No.: |
13/154877 |
Filed: |
June 7, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12419423 |
Apr 7, 2009 |
7982958 |
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13154877 |
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11500993 |
Aug 9, 2006 |
7532407 |
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12419423 |
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Current U.S.
Class: |
353/20 |
Current CPC
Class: |
H04N 9/3105 20130101;
H04N 9/3144 20130101 |
Class at
Publication: |
353/20 |
International
Class: |
G03B 21/14 20060101
G03B021/14 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 9, 2005 |
JP |
2005-231052 |
Claims
1. A projection-type image display apparatus, comprising the
following in a housing thereof: a light source; a lighting optical
system; penetration-type image display elements configured for use
of R-color, G-color and B-color; an optical synthesizing portion;
and a projection lens, wherein: said projection-type image display
elements configured for use of the R-color, G-color and B-color are
attached with a cross dichroic prism, which constructs said optical
synthesizing portion, in one body, on optical surfaces thereof
differing from each other, said cross dichroic prism attached with
said image display elements can be freely and detachably attached,
so that an emission surface differing from the surfaces, on which
said image display elements are attached, opposes to an incident
surface of said projection lens, and also a reflection-type
polarizing plate and an absorption-type polarizing plate are
disposed, sequentially, between the emission surface of said cross
dichroic prism and the incident surface of said projection lens,
from the emission surface of said cross dichroic prism, opposing to
said cross dichroic prisms, and the degree of polarization of said
reflection=type polarizing plate is larger than that of said
absorption-type polarizing plate.
2. The projection-type image display apparatus, according to claim
1, wherein on a side of the incident surface of said projection
lens is provided a support member for attaching said cross dichroic
prism, on which said image display elements are attached, freely
and detachably.
3. The projection-type image display apparatus, according to claim
2, wherein a member configured for use of positioning is attached
on said support member, on the side of the incident surface of said
projection lens, by fixing said member configured for use of
positioning on one surface, on which said cross dichroic prism is
not attached and further said reflection-type polarizing plate and
said absorption-type polarizing plate are not disposed.
4. A projection-type image display apparatus, comprising the
following is a housing thereof: a light source; a lighting optical
system; penetration-type image display elements configured for use
of R-color, G-color and B-color; an optical synthesizing portion;
and a projection lens, wherein: said penetration-type image display
elements configured for use of the R-color, G-color and B-color
are, at least, attached with a cross dichroic prism, which
constructs said optical synthesizing portion, in one body together
with said cross dichroic prism, on optical paths opposing surfaces
of said cross dichroic prism differing from each other, said cross
dichroic prism attached with said image display elements can be
freely and detachably attached, so that an emission surface
differing from the surfaces, on which said image display elements
are attached, opposes to an incident surface of said projection
lens, and also a reflection-type polarizing plate and an
absorption-type polarizing plate are disposed, sequentially,
between the emission surface of said cross dichroic prism and the
incident surface of said projection lens, from the emission surface
of said cross dichroic prism, opposing to said cross dichroic
prisms, and the degree of polarization of said reflection-type
polarizing plate is larger than that of said absorption-type
polarizing plate.
5. The projection-type image display apparatus, according to claim
4, wherein on a side of the incident surface of said projection
lens is provided a support member for attaching said cross dichroic
prism, on which said image display elements are attached, freely
and detachably.
6. The projection-type image display apparatus, according to claim
5, wherein a member for use of positioning is attached on said
support member, on the side of the incident surface of said
projection lens, by fixing said member for use of positioning on
one surface, on which said cross dichroic prism is not attached and
further said reflection-type polarizing plate and said
absorption-type polarizing plate are not disposed.
7. The projection-type image display apparatus, according to claim
5, wherein said cross dichroic prism has reflection-type polarizing
prisms, which are fixed on surfaces neighboring with each other,
and said R-color, G-color and B-color display elements are attached
on said reflection-type polarizing prisms, on surfaces differing
thereof from each other.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 12/419,423, filed Apr. 7, 2009, which, in turn, is a
continuation of U.S. application Ser. No. 11/500,993, filed Aug. 9,
2006 (now U.S. Pat. No. 7,532,407); and which applications claim
priority from Japanese Patent Application 2005-231052, filed Aug.
9, 2005, the entire contents of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a projection-type image
display apparatus, for modulating light intensity of lights
irradiated from an illumination optic system, through liquid
crystal image display elements (i.e., panels) for use of lights of
R, G and B, in particular, applying polarization effect therein,
thereby forming an optic image, and projecting said optic image
upon a screen through a projection optic system.
[0003] Conventionally, the projection-type image display apparatus
was already known by a name, such as, a liquid crystal projector or
the like, for example, i.e., containing an optical unit, as well
as, an electric source circuit and/or a video driver circuit within
a housing thereof, for projecting the optic image that is formed
through modulating the light intensity upon the lights from a light
source, with applying polarization effect thereto, so as to vary
the density for each of pixels, depending on an image signal
through light valve elements for use of R-, G- and B-lights, and
thereby projecting the said optic image formed onto the screen or
the like, by means of a projection lens. Further, at present, as
such the light valve element mentioned above is also widely known
and practically used, for example, so-called a transmission or a
transparent-type liquid crystal panel, or a reflection-type liquid
crystal panel, etc.
[0004] As the optic unit of such the projection-type image display
apparatus is also already known an optic unit, as is disclosed in
Japanese Patent Laying-Open No. 2004-126496 (2004) or Japanese
Patent Laying-Open No. 2004-184889 (2004), for example, wherein the
optic image is formed through cross dichroic prisms, functioning as
a color synthesizing element, after conducting the light-intensity
modulation on the lights, which are divided with applying the
polarization functions, by means of the reflection-type liquid
crystal panels for use of the R-, G- and B-lights, and thereby
projecting the optical image formed onto the screen or the like,
through the projection lens.
[0005] Also, an optical unit is already known, in Japanese Patent
Laying-Open No. 2005-12303 (2005), for example, (in particular, in
the second embodiment shown in FIGS. 3 and 4) wherein the optic
image is formed also through the cross dichroic prisms, as the
color synthesizing element, but conducting the light intensity
modulations of R, G and B lights, with applying the
transparent-type liquid crystal panels (or, the transparent-type
light valves) therein, in the place of such the reflection-type
liquid crystal panels as mentioned above, and thereby projecting
the optic image formed onto the screen or the like, through the
projection lens.
[0006] Also further is already known a cooling structures within
the optic unit of projecting the optic image on the screen or the
like, which is formed through the cross dichroic prisms while
conducting the light intensity modulations of R, G and B lights
with applying the reflection-type liquid crystal panels (or, the
reflection-type light valves) or the transparent-type liquid
crystal panels (or, the transparent-type light valves) therein.
SUMMARY OF THE INVENTION
[0007] By the way, as the light source within the projection-type
display mentioned above, such as, the liquid crystal projector,
etc., in general, there is used a high-pressure discharge lamp,
such as, a metal halide lamp and a high-pressure mercury lamp,
etc., for example, because of the reasons that the conversion
efficiency there of is high and that lights can be easily obtained
therewith, being very similar to that irradiated from a point-like
light source. However, with such the liquid crystal projector, it
is tried to obtain high-brightness, as well as, high-definition,
accompanying with large-sizing of a display screen thereof, i.e.,
adopting a high-output lamp therein (for example, the metal halide
lamp having an electric power, being equal to 250 W or larger than
that), and for this reason, ill-influences are exerted on the
characteristics of the liquid crystal panels, by the heats
generating from such the light radiation source of high output, and
further the heat-generation of the liquid crystal panels due to
irradiation of strong lights from that light radiation source.
[0008] Then, conventionally, within such the projector, for the
purpose of preventing various portions of the apparatus including
the liquid crystal panel (in particular, a lamp and a controller
portion thereof) from increasing of temperature, i.e., protecting
them from the ill-influences thereof, there is provided a fan for
use of air cooling, and thereby introducing/circulating cooling air
from an outside of the apparatus into an inside of a housing
thereof. Further, as is already known in Japanese Patent
Laying-Open No. 2004-354795 (2004), an attempt is made for cooling
down the cross dichroic prisms including the liquid crystal panels,
which is installed within the housing while being mounted on an
attachment member having a cooling fin on one-side surface thereof,
thereby to obtain cooling through a cooling air current within that
housing.
[0009] On the other hand, with the reflection-type liquid crystal
panels or the transparent-type liquid crystal panels, to be applied
as the light intensity modulating elements within such the optic
unit, also demand is made remarkably for small-sizing, as well as,
for low-costs thereof, in recent years, and therefore the strong
lights emitted from the light radiation source are irradiated upon
the liquid crystal panels, each having a smaller surface area
thereof. For this reason, the heat generation on the liquid crystal
panel due to the light irradiation comes up to be large much more,
but on the contrary to that, it is difficult by any possibility, to
suppress such the heat-generation on the liquid crystal panel as
was mentioned above, fully by only means of the introduction and/or
the circulation of cooling air into the inside of the apparatus by
means of the air-cooling fan mentioned above.
[0010] Then, according to the present invention, by taking the
drawbacks of the conventional arts mentioned above into the
consideration thereof, i.e., an object thereof is to provide the
practical structures of the optic unit, in particular, for enabling
to achieve the optical performances desired, depending on necessity
thereof, dissolving those deteriorations in performances that are
caused due to the heat generation mentioned above, within the
projection-type image display apparatus, representatively, such as,
the liquid crystal projector, for example, upon which requirements
are made strongly for the high-definition, as well as the
high-brightness thereof, and in other words, an improved
projection-type image display apparatus.
[0011] Namely, according to the present invention, first of all,
there is provided a projection-type image display apparatus,
comprising the followings in a housing thereof: a light source; an
illumination optic system; penetration-type image display elements
for R-, G- and B-lights; an optical synthesizing means, and a
projection lens, wherein the R-light penetration-type image display
element, the G-light penetration-type image display element and the
B-light penetration-type image display element are attached on
surfaces different from each other of the said cross dichroic
prisms, for building up the optical synthesizing means, onto which
the display elements are attached, in one body, so that the said
cross dichroic prisms attached with the display elements thereon
can be attached, detachably, while opposing to a surface different
from those, on which the display elements are attached, to an
incident surface of the projection lens.
[0012] Further, according to the present invention, there is also
provided a projection-type image display apparatus, comprising the
followings in a housing thereof: a light source; an illumination
optic system; reflection-type image display elements for R-, G- and
B-lights; an optical synthesizing means, and a projection lens,
wherein the R-light penetration-type image display element, the
G-light penetration-type image display element and the B-light
penetration-type image display element are attached with the said
cross dichroic prisms for building up the optical synthesizing
means, in one body, on optical paths opposing to surfaces thereof
different from each other, so that the said cross dichroic prisms
attached with the display elements thereon can be attached,
detachably, while opposing to a surface different from those, on
which the display elements are attached, to an incident surface of
the projection lens.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Those and other objects, features and advantages of the
present invention will become more readily apparent from the
following detailed description when taken in conjunction with the
accompanying drawings wherein:
[0014] FIG. 1 is a block diagram for showing the entire structures
of a projection-type image display apparatus, which applies
transparent-type liquid crystal elements (or panels) therein,
according to an embodiment 1 of the present invention;
[0015] FIG. 2 is a partially exploded perspective view for showing
the detailed structures of a cross dichroic prisms, as being an
optical synthesizing means, and the transparent-type liquid crystal
elements for use of R, G and B color lights, in the projection-type
image display apparatus mentioned above;
[0016] FIG. 3 is also a partially exploded perspective view for
showing the detailed structures of the cross dichroic prisms, as
being the optical synthesizing means, and the transparent-type
liquid crystal elements for use of R, G and B color lights, in the
projection-type image display apparatus mentioned above;
[0017] FIG. 4 is a partially enlarged perspective view for showing
the details of the cross dichroic prisms mentioned above;
[0018] FIG. 5 is a partially enlarged perspective view for showing
the condition when installing the cross dichroic prisms, on which
are attached the transparent-type liquid crystal elements for use
of R, G and B color lights, onto an attachment structure;
[0019] FIG. 6 is also a partially enlarged perspective view for
showing the condition when installing the cross dichroic prisms, on
which are attached the transparent-type liquid crystal elements for
use of R, G and B color lights, onto the attachment structure;
[0020] FIG. 7 is a partially enlarged perspective view for showing
the condition after installing the cross dichroic prisms, on which
are attached the transparent-type liquid crystal elements for use
of R, G and B color lights, onto the attachment structure;
[0021] FIG. 8 is a perspective view of the projection lens after
being installed with the cross dichroic prisms, on which are
attached the transparent-type liquid crystal elements for use of R,
G and B color lights, onto the attachment structure;
[0022] FIG. 9 is a block diagram for showing the entire structures
of a projection-type image display apparatus, according to an
embodiment 2 of the present invention;
[0023] FIG. 10 is a block diagram for showing the entire structures
of a projection-type image display apparatus, applying
reflection-type image display elements therein, according to an
embodiment 3 of the present invention; and
[0024] FIG. 11 is a partially enlarged perspective view for showing
the details of the structures for installing the optical
synthesizing means, including the cross dichroic prisms, thereon in
the projection-type image display apparatus according to the
embodiment 3.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Hereinafter, embodiments according to the present invention
will be fully explained by referring to the attached drawings.
[0026] First of all, FIG. 1 attached herewith shows the entire
structures of a projection-type image display apparatus according
to an embodiment 1, in particular, applying transparent-type liquid
crystal image display elements (or panels) therein, as those for
modulating light strength or intensity of three color lights, i.e.,
R, G and B lights, within an optic unit.
[0027] In the figure, a light source 10 is made up with a white
color lamp, i.e., so-called a high-pressure lamp, such as, the
metal halide lamp or the high-pressure mercury lamp or the like, as
was mentioned above, for example, or alternately a xenon lamp, a
mercury-xenon lamp, or a halogen lamp, etc. Further, a reference
numeral 11 in the figure depicts a concave mirror (i.e., a
reflector) having a reflection surface of an ellipsoidal surface or
a parabolic surface, which is attached around that lamp, and it
emits the light (i.e., white light) irradiated from the lamp into
one (1) direction.
[0028] Next, the light emitting from this light source 10,
penetrating through a pair of multi-lenses 21 and 22 disposed on an
optical axis thereof (however, each multi-lens is made up with a
large number lens cells, which are aligned in matrix-like), comes
to be a white light having a uniform light strength within an
irradiation surface area, and further it is incident upon a
polarized-light conversion element 23, which is constructed with
lines of rhombic or diamond-shaped prisms, each having about a half
(1/2) size of the lens width, which are disposes to be fitting to a
pitch of the vertical direction on the each optical axis of the
lenses. Upon the polarized-light conversion element 23, a polarized
light separation film is provided on a prism surface thereof, and
therefore the incident light thereon is divided or separated into a
P-polarized light and a S-polarized light through that polarized
light separation film. The P-polarized light penetrates through the
polarized light separation film as it is, to be emitted outside. On
the other hand, after being reflected upon the polarized light
separation film and further being reflected again into the
direction of the inherent optical axis within the diamond-shaped
prisms neighboring to each other, the S-polarized light is rotated
in the polarization direction by 90.degree. through a .lamda./2
phase difference plate, which is provided on an emission surface of
the prism. Thus, it is converted into the P-polarized light and is
emitted from. In this manner, only the P-polarized light is emitted
from the polarized-light conversion element 23.
[0029] The P-polarized light from the polarized-light conversion
element 23 is further condensed by a collimator lens 24, which has
a positive refractive power and equipped with a condensing
function, and is incident upon an optic system, which will be
explained below, through a filter 25, for example.
[0030] Thus, the P-polarized light incident thereupon, after being
separated G-color light therefrom through a R- and B-lights
penetrating and G-light reflecting dichroic mirror 31, i.e., the
G-light separated therefrom is further reflected upon a first white
color reflection mirror 32, to be incident upon an image display
element portion which will be explained in details thereof later,
through a collimator lens 33. On the other hand, the R-light and
the B-light penetrating through the dichroic mirror 31 mentioned
above, next after being color-separated the B-light by a R-light
penetrating and B-light reflecting dichroic mirror 34, i.e., the
B-light separated therefrom is incident upon the image display
element portion through a collimator lens 33. Lastly, the R-light
penetrating through a dichroic mirror 34, after penetrating through
the collimator lens 33, is reflected upon a white light reflection
mirror 35, and further after penetrating through another collimator
lens and reflected upon a third white light reflection mirror 36,
it is incident upon the image display element portion through a
collimator lens 33. In this manner, the P-polarized light from the
light source mentioned above is separated into the R-light, the
B-light and the G-light, respectively, with using the polarization
thereof, and they reach to the image display element portion which
will be mentioned in details thereof below.
[0031] However, the image display element portion 40 mentioned
above comprises an optical synthesizing means being cubic-like in
the external configuration thereof, which is made up with four (4)
pieces of triangular prisms, i.e., so-called cross dichroic prisms
41. And, upon the incident surfaces of the cross dichroic prisms
41, each separating from one another (but, only one (1) surface
41-1 is shown in the figure), as is shown in FIG. 2 attached
herewith, are attached a R-light penetration type image display
element 42R, a G-light penetration type image display element 42G,
and a B-light penetration type image display element 42B,
respectively, in one body (or, as a unit), through jigs 43 for
fixing, each providing an opening 44 at a central portion of a
metal plate and also projections 45 formed through cutting at every
corners thereof. Further, those of the R-light penetration type
image display element 42R, the G-light penetration type image
display element 42G, and the B-light penetration type image display
element 42B are fixed on the fixing jigs 43, respectively, through
a solder or an adhesive, for example, and they are positioned and
fixed at the predetermined portions with respect to three (3)
incident surfaces, at high accuracy thereof, so as to synthesize
the lights from the light source, penetrating therethrough while
being modulated the intensity thereof, respectively.
[0032] Further, as is shown in FIG. 3 attached herewith, on lower
surfaces of cross dichroic prisms 41, being attached with the
R-light penetration type image display element 42R, the G-light
penetration type image display element 42G, and the B-light
penetration type image display element 42B thereon, there is also
attached a seat portion 46, having a shape being almost similar to
the cross-section of the prisms 41 mentioned above, in one (1) body
through ah adhesive, for example. Further, on two (2) sides of this
almost square-shaped seat portion 46, neighboring to each other,
are formed projection portions (or frames) 47 and 47 for use of
positioning, crossing on each other. With this, it is possible to
fix the seat portion 46 at the desired position on the lower
surfaces of the cross dichroic prisms 41, correctly, but only by
mounting the lower surfaces of the prisms 41 on the seat portion 46
and abutting it onto the projection frames 47 and 47, simply.
Further, on the lower side surface of this seat portion are formed
a plural number of projections 48 for use of positioning (two (2)
pieces in this example), in advance, correctly and at high
accuracy, at a predetermined position, as will be explained later,
so that it can be positioned and fixed, easily, onto the attachment
structures formed on the side of the projection lens 60.
[0033] Again, turning back to FIG. 1 mentioned above, after being
modulated in the intensity thereof through the respective
penetration-type image display elements, within the image display
element portion 40 which was explained in the above, the lights
synthesized within the cross dichroic prisms 41, as being the color
synthesizing means, is enlarged and projected onto a screen 80, for
example, through a projection lens, the details of which will be
explained below. However, this image display element portion 40 has
such the structures of being detachable opposing to the incident
surface of the projection lens 60. Further, reference numerals 61
and 62 in the figure depict a reflection-type polarizing plate and
an absorption-type polarizing plate, which are provided on the
incident side surface of the projection lens 60.
[0034] Following to the above, by referring to FIGS. 4 to 8
attached herewith, there is shown an example of the structures
(i.e., a supporting portion) for enabling the image display element
portion 40 to be detachable on the incident side surface of the
projection lens 60. As apparent from those figures, on the incident
side surface of the projection lens 60 is provided so-called an
attachment portion 70 for the image display element, for attaching
the image display element portion 40 thereon, in a detachable
manner. However, as is also apparent from FIG. 4, this image
display element attachment portion 70 is formed into a
predetermined shape, such as, through the injection molding of
plastic or the like, for example. With the present example, it is
almost square in the external configuration thereof, and further it
is formed into such a shape that it has a projection portion 71 at
around a central portion thereof, i.e., on a surface opposing to
the incident surface of the projection lens 60.
[0035] And, on this projection portion 71 is formed a square shaped
portion 72, being opened therein, with fitting to an exit surface
of the cross dichroic prisms 41 mentioned above (i.e., the surface
of the cross dichroic prisms 41, but differing from those mounding
the R-light penetration type image display element 42R, the G-light
penetration type image display element 42G, and the B-light
penetration type image display element 42B thereon). And, further
below that opening portion 72 is formed so-called a tongue-like
fixing portion 73 in one body (or as a unit), for attaching the
image display element portion 40, i.e., the cross dichroic prisms
on an upper surface thereof, detachably. And, on the upper surface
of this tongue-like portion 73 are formed holes 74 and 74, into
which the projections 48 for use of positioning shown in FIG. 3
mentioned above are inserted to be fitted, at predetermined
positions thereof, correctly and with high accuracy.
[0036] In FIGS. 5 an 6 attached herewith is shown the condition
where the image display element portion 40, the detailed structures
of which are explained in the above, is mounted on the attachment
portion 70 for the image display element, which is attached on the
incident side surface of the projection lens 60. Also, in FIG. 7
attached herewith is shown the condition after mounting the image
display element portion 40 on the attachment portion 70 for the
image display element, and further, in FIG. 8 attached herewith the
condition after mounting the image display element portion on the
incident side surface of the projection lens 60, respectively.
[0037] As was mentioned above, in the projection-type image display
apparatus according to the embodiment 1, in particular, applying
the penetration-type liquid crystal image display elements (panels)
as those for modulating the light intensities of the three (3)
color lights, R, G and B lights, with adopting the structures for
enabling to amount the image display element portion 40, which is
built up with attaching the R-light penetration type image display
element 42R, the G-light penetration type image display element
42G, and the B-light penetration type image display element 42B
upon the three (3) surfaces of the cross dichroic prisms,
neighboring to one another, onto the image display element
attachment portion 70 attached on the incident side surface of the
projection lens 60, in particular, with applying the tongue-like
fixing portion 73, and further the positioning projections 48 and
the fitting holes 74 thereof, easily, at the correct position, in
detachable manner, it is possible to exchange only the image
display element portion 40, easily.
[0038] Thus, with the projection-type image display apparatus
according to the embodiment 1, though the heat generation also
comes up to be large more and more on the liquid crystal panels,
due to irradiation of the stronger light irradiated from the light
radiation source upon a small area of the liquid crystal panel,
accompanying with the remarkable improvement for achieving the high
definition and the high brightness, however according to the
present invention, being accomplished by taking the fact into the
consideration thereof, that it is difficult at all to suppress the
heat generation mentioned above on the liquid crystal panel only by
the introduction and the circulation of the cooling air into the
inside of the apparatus by means of the conventional air-cooling
fan, while also on the other hand being achieved by paying
attention onto the liquid crystal image display elements (the
panels), on which improvement is made remarkably for achieving the
low-costs and the small-sizing thereof in recent years, it is to
bring the optic unit being inescapable or unavoidable from
deterioration thereof due to the heat generation mentioned above,
in particular, the image display element portion made up with the
cross dichroic prisms equipped with the liquid crystal image
display elements (i.e., the panels), to be exchangeable with a new
image display element portion, with easy or simple work, depending
on necessity thereof, accompanying with the deterioration thereof,
and thereby enabling to obtain the desired optical performance,
always therefrom.
[0039] Also, within the projection-type image display apparatus
according to the embodiment 1, it is preferable to provide a
supporting portion for mounting the cross dichroic prisms thereon,
on which the display elements are attached, in a freely detachable
manner, in particular, on the incident surface side of the
projection lens, or to fix a member for positioning on a surface of
the cross dichroic prisms where no display element is attached, to
be attached onto that supporting portion, which is provided on the
incident surface side of the projection lens. And, it is also
preferable to put a member for preventing the reflection between
the incident surface side of the projection lens and the projection
lens.
[0040] In more details thereof, as is apparent from the
above-mentioned, in the manufacturing processes thereof, it is
possible to fix the image display element portion 40 at the correct
position on that seat portion 46, which is built up with the
R-light penetration type image display element 42R, the G-light
penetration type image display element 42G, and the B-light
penetration type image display element 42B, being attached at high
accuracy on the three (3) pieces of surfaces of the cross dichroic
prisms 41, neighboring to one another, but only through fixing it
while abutting onto the positioning projection frames 47 and 47 on
that seat portion 46. Then, with a simple work, i.e., inserting the
positioning projections 48 formed on the lower surface of that seat
portion 46 into the fitting holes 74, which are formed on a surface
of the tongue-like fixing portion 73 of the image display element
attachment portion 70, it is possible to position that image
display element portion 40, again, correctly, with respect to the
optic system of the projection-type image display apparatus
mentioned above, in particular, on the light paths of R-light,
G-light and B-light thereof.
[0041] Also, the reflection-type polarizing plate 61 and the
absorption-type polarizing plate 62 are disposed on the incident
surface side of the projection lens 60 (i.e., between the
projection lens 60 and the cross dichroic prisms 41), according to
the embodiment 1 mentioned above, and thereby building up the
structures for absorbing the reflection of incident light upon the
projection lens 60. With such the structures, it is possible to
obtain the projection-type image display apparatus prohibiting to
generate a ghost or the like due to the reflection light, for
example, i.e., being more superior in the optical performances
thereof. Further in more details thereof, it is preferable to set a
degree of polarization of the main reflection-type polarizing plate
61 to be larger than that of the absorption-type polarizing plate
62, since it is possible to absorb the reflection light upon the
projection lens much more therewith. However, those reflection-type
polarizing plate 61 and absorption-type polarizing plate 62 are
separated from the image display element portion 40, i.e., they are
not detachable in the structures thereof.
[0042] FIG. 9 attached herewith shows the projection-type image
display apparatus, according to an embodiment 2. As is apparent
from the figure, in particular, according to this embodiment 2, it
is so constructed that the optical paths within the inside thereof
can be protected from dusts, which are introduced from an outside
of the apparatus, by disposing the optic system, i.e., for
separating the lights emitting from the light source 10 into the
colors thereof, and thereby entering them upon the three (3) pieces
of surfaces of the cross dichroic prisms 41 building up the image
display element portion 40 neighboring to one another, i.e., the
R-light penetration type image display element 42R, the G-light
penetration type image display element 42G, and the B-light
penetration type image display element 42B, within an inside of a
dustproof housing 90 made of a plastic, for example.
[0043] In more details thereof, as is apparent from the figure, the
pair of the multi-lenses 21 and 22, the polarized-light conversion
element 23, the collimator lens 24 and the filter 25, further the
R- and B-lights penetrating and G-light reflecting dichroic mirror
31, the first white color reflection mirror 32 and the collimator
lens 33, further the R-light penetrating and B-light reflecting
dichroic mirror 34 and the collimator 33, and further the second
white light reflection mirror 35, the collimator lens 33, the third
white light reflection mirror 36, and the collimator lens 33 are
sealed within the housing 90 made of a plastic, air-tightly.
[0044] With the embodiment 2, the details of which was explained in
the above, there was mentioned only the case of applying the
penetration-type liquid crystal image display elements (i.e., the
panels), in particular, to be the liquid crystal image display
elements (i.e., the panels) for modulating the light intensities of
the three (3) color lights, i.e., the R-light, G-light and B-light,
within the optic unit thereof; however, it would be apparent that
the present invention should not be restricted only to such the
penetration-type liquid crystal image display elements (i.e., the
panels), but is also applicable into the projection-type image
display apparatus adopting the refection-type liquid crystal image
display elements (i.e., the panels), for example, in the place
thereof.
[0045] FIGS. 10 and 11 attached herewith show the structures,
mainly around a reflection polarized-light prism, including cross
dichroic prisms 410 and the liquid crystal image display elements
(i.e., the panels) attached on the three (3) neighboring surfaces
thereof, in particular, being constructed to be detachable onto the
apparatus, in case of applying reflection type liquid crystal image
display elements (i.e., panels), according to an embodiment 3.
[0046] First, FIG. 10 shows the structures of the projection-type
image display apparatus applying such reflection-type liquid
crystal image display elements (i.e., the panels) as was mentioned
therein, wherein the P-polarized light emitted from the light
source similar to that mentioned above, after being separated in
the color into thereof G-light upon a R- and B-lights penetrating
and G-light reflecting dichroic mirror 31', and in particular, the
G-light separated, it is reflected upon a first white color
reflection mirror 32' through a collimator lens 33', and after
being incident upon a correction polarization plate 37 through that
collimator 33', again, is incident upon an image display element
portion 400 having a reflection-type polarization prism therein. On
the other hand, R-light and B-light penetrating through the
dichroic mirror 31' are separated in the color thereof, next, upon
a R-light penetrating and B-light reflecting dichroic mirror 34',
and thereafter the B-light separated is incident upon the image
display element portion 400. Finally, the R-light penetrating
through the dichroic mirror 34' is also incident upon the image
display element portion 400, in the similar manner.
[0047] However, as is apparent from the figure, this image display
element portion 400 comprises cross dichroic prisms 410, i.e., a
light synthesizing means being cube-like in the outer configuration
thereof, and combining four (4) pieces of triangular prisms with,
and onto the three (3) pieces of surfaces thereof, neighboring to
one another, are connected or bonded a R-light reflection-type
image display prism 420R, a G-light reflection-type image display
prism 420G, and a B-light reflection-type image display prism 420B,
respectively, so as to build up necessary light paths. And, upon
surfaces of those reflection-type image display prisms 420 opposing
to the bonding surfaces thereof are attached a reflection-type
G-light liquid crystal image display element (i.e., panel) 450G, a
reflection-type B-light liquid crystal image display element (i.e.,
panel) 450B, and a reflection-type R-light liquid crystal image
display element (i.e., panel) 450R, respectively, through an
analyzer 430 and a 1/2 wavelength plate 440 each. Further, a
reference numeral 460 in the figure depicts convex lenses, which
are attached on side surfaces of the reflection-type image display
prisms 420, for the purpose of introducing the R-, G- and B-lights
therein, respectively. Also, it is possible to build up the optical
paths necessary, by using reflection-type of polarized-light
mirrors, not shown in the figure, but in the place of the
reflection-type image display prisms 420.
[0048] Within the projection-type image display apparatus applying
the reflection-type liquid crystal image display elements (i.e.,
the panels) having such the structures therein, but similar to
those shown in the embodiments 1 and 2, the optic image is formed
through the cross dichroic prisms 410, functioning as being the
color synthesizing means after modulating the light intensities of
the lights through the R-, G- and B-lights reflection-type image
display prisms 420 mentioned above, and it is projected onto the
screen 80 or the like, through the projection lens 60.
[0049] Next, FIG. 11 shows the image display element portion 400,
the detailed structures of which was explained in the above, and in
particular, the structures for attaching or mounting the cross
dichroic prisms 410, including the reflection-type image display
prisms 420. However, in this embodiment, also in the similar manner
to that shown in FIG. 3 mentioned above, a bottom surface of the
cross dichroic prisms 410 is fixed onto an upper surface of the
seat portion 46 mentioned above, with using the positioning
projection frames 47 and 47 formed thereupon. And, the positioning
projections 48 formed on the lower surface of that seat portion 46
into the fitting holes 74, which are formed in advance on the
surface of the tongue-like fixing portion 73 of the image display
element attachment portion 70, are also inserted into the fitting
holes 74 and 74, which are formed on the surface of the tongue-like
fixing portion 73 of the image display element attachment portion
70, the details of which were explained in FIG. 4 mentioned above,
and thereby enabling this image display element portion 400 to be
attached or mounted at the correct position, simply or easily, in a
detachable manner.
[0050] As was mentioned above, also with the projection-type image
display apparatus applying therein the liquid crystal image display
elements (i.e., panels) 450 explained in the above, in the similar
manner, the optic unit, inescapable from the deterioration thereof
accompanying with the remarkable advances in the high definition
and the high brightness in recent years, can be built up with the
reflection-type image display elements (i.e., the panels),
depending on the necessity thereof, i.e., the cross dichroic prisms
410, including the reflection-type polarization prisms 420, etc.,
can be formed in one body (as a unit), to be exchangeable with a
new image display element portion through simple works, thereby
enabling it to exhibit or keep the desired optical performances
thereof, always.
[0051] In more details, as is similar to that mentioned above, in
the manufacturing processes thereof, it is also possible to
position the image display element portion 400, again, correctly on
the light paths of R-light, G-light and B-light, only by fixing the
image display element portion 400 at the correct position on that
seat portion 46, which is built up with the cross dichroic prisms
410 and also the R-, G- and B-light reflection-type polarization
prisms 420 attached on the three (3) surfaces thereof neighboring
to one another, and also inserting this into the fixing holes 74
which are disposed and formed correctly on the surface of the
tongue-like fixing portion 73 of the image display element
attachment portion 70.
[0052] In addition thereto, according to the embodiment 3, it is
also possible to achieve the projection-type image display
apparatus being more superior in the optical performances thereof,
i.e., prohibiting to generate a ghost or the like due to the
reflection light, for example, with disposing the reflection-type
polarizing plate 61 and the absorption-type polarizing plate 62 on
the incident surface side of the projection lens 60 (i.e., between
the projection lens 60 and the cross dichroic prisms 410). Also, in
the similar manner to that of FIG. 9 mentioned above, it is also
possible to obtain the structures for protecting the optical paths
within the inside thereof, while disposing the optic system, which
guides the lights incident upon the three (3) pieces of surfaces of
the image display element portion 400 neighboring to one another,
within the housing 90 made of a plastic, for example.
[0053] In the projection-type image display apparatus according to
the embodiment 3, it is preferable to provide the supporting
portion on the incident surface side of the projection lens, for
attaching or mounting the cross dichroic prisms thereon in
detachable manner, each of which is attached with the display
element. And, it is also preferable to fix the member for
positioning on the surface of the cross dichroic prisms where no
display element is attached, to be attached onto the supporting
portion, which is provided on the incident surface side of the
projection lens. Further, for each of the cross dichroic prisms, it
is preferable to comprise the reflection-type polarizing prism,
which is fixed on the surfaces neighboring to each other, and it is
also preferable that the R-, G- and B-light reflection-type image
display elements are attached on different surfaces of the
reflection-type polarizing prisms. In addition thereto, it is also
preferable to put a member for antireflection between the exit side
of the cross dichroic prisms and the projection lens.
[0054] In those embodiments 1 to 3, although the explanation was
given on an assumption that the P-polarized lights can be obtained
from the illumination system (i.e., the light source 10 mentioned
above); however they should not be restricted only to that. For
example, it may be so constructed that only S-polarized lights can
be emitted from, in the place thereof. However, in more details
thereof, in case where the lights emitted from the light source 10
building up the illumination system are the S-polarized lights,
those lights are reflected upon the reflection-type polarization
prisms 420, functioning as being the polarized-light conversion
devices, and they are converted into the P-polarized lights in
conformity with image signals through the reflection-type liquid
crystal image display elements (i.e., panels) 450G, 450B and 450R,
to be incident upon the cross dichroic prisms (i.e., the color
synthesizing device) 410. In this instance, by taking the
characteristics of the prisms mentioned above into the
consideration thereof, in particular, with provision of a .lamda./2
plate between the polarized-light conversion devices (i.e., the
reflection-type polarization prisms 420B and 420 R) thereof,
corresponding to B-light and R-light, and the cross dichroic prisms
410 building up the color synthesizing device, it is possible to
change the incident lights upon that prisms into the S-polarized
lights, and thereby obtaining preferable dichroic
characteristics.
[0055] As is apparent from the above, with the projection-type
image display apparatuses, according to the embodiments 1 to 3,
enabling the cross dichroic prisms, each being attached with the
display element thereon, to be mounted detachably, it is possible
to exhibit or keep the desired optical performances thereof,
always, by exchanging the prisms with a new image display element
portion, depending upon the necessity, accompanying with
deterioration of the performances thereof, with simple works.
[0056] The present invention may be embodied in other specific
forms without departing from the spirit or essential feature or
characteristics thereof. The present embodiment(s) is/are therefore
to be considered in all respects as illustrative and not
restrictive, the scope of the invention being indicated by the
appended claims rather than by the forgoing description and range
of equivalency of the claims are therefore to be embraces
therein.
* * * * *