JP2003029210A - Rear face projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a small rear face projection type display device using a lamp of a vertical lighting method. SOLUTION: A projection type display device part 100 has a light source 101, a folding mirror 102, a first lens plate 103, a second lens plate 104, a cross dichroic mirror 105, folding mirrors 106 and 107, a dichroic mirror 108, polarized beam splitters 109R, 109G and 109B, reflection type light valves 110R, 110G and 110B, a cross dichroic prism 111 and a projection lens 112. Respective members other than the light source 101 and the folding mirror 102 are disposed perpendicularly on a virtual reference plane A. Light source light emitted by the light source 101 advances in a Z direction, turned at a right angle by the folding mirror 102 and made incident on the first lens plate 103.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear projection type display device for projecting a projected image on a transmissive screen.

[0002]

2. Description of the Related Art A rear projection display device is known which projects light modulated by a light valve onto a transmissive screen.
FIG. 6 is a cross-sectional view of a conventional rear projection display device viewed from the side. In FIG. 6, the projection device 1 is arranged in the housing 5. The projection device 1 has a light valve and modulates the illumination light from the lamp 3 based on the image signal. Projector 1
The modulated light emitted from is incident on the bending mirror 3 via the projection lens 2. The modulated light that has entered the folding mirror 3 is reflected by the mirror 3 and projected onto the transmissive screen 4 from the inside of the housing 5. The projection image projected on the transmission screen 4 is observed from the outside of the housing 5 (transmission screen 4).

[0003]

In the above-mentioned rear projection type display device, since the lamp 3 is obliquely arranged, it is not possible to use a vertical lighting type long-life lamp.

It is an object of the present invention to provide a rear projection type display device in which the device is downsized while using a long-life lamp.

[0005]

The present invention will be described with reference to FIGS. 1 and 5 showing an embodiment. (1) In the rear projection display device according to the first aspect of the present invention, a straight line connecting the tip ends of the discharge electrodes is matched with the direction of substantially gravity to supply illumination light, and a light flux from the light source 101 is bent. Illumination optical system 102, 103,
104, light valves 110R, 110G, 110B having a rectangular shape and modulating illumination light from the illumination optical systems 102, 103, 104 based on image signals, and modulated light fluxes from the light valves 110R, 110G, 110B. Projection optical system 112 that bends and ejects, and projection optical system 1
The light valve 110R includes a reflection optical system 200 that reflects the light flux emitted from the light source 12, and a transmissive screen 300 on which an image formed by the light flux reflected by the reflection optical system 200 is projected.
Light valve 1 which is a surface perpendicular to 110G and 110B
By disposing the light valves 110R, 110G, 110B so that the virtual reference plane A including one side of the 10R, 110G, 110B forms a predetermined angle α with respect to the plane orthogonal to the gravity direction, Achieve the purpose. (2) The invention according to claim 2 is the rear projection display device according to claim 1, wherein the illumination optical system includes integrators 103 and 104 that uniformly illuminate the light valves 110R, 110G, and 110B. 10
3, 104 are light valves 110R, 110G, 11
It is characterized in that it is arranged according to the inclination of 0B. (3) The invention according to claim 3 is the rear projection display device according to claim 1, wherein the transmissive screen 300 is arranged parallel to the direction of gravity, and a surface parallel to the transmissive screen 300 and a reflective optical system. 200 and a predetermined angle α, and the axis passing through the center of the reflected light beam is the transmissive screen 300.
It is characterized in that it has a relationship of α = 90−2θ ± β with an incident angle β incident on. (4) The invention according to claim 4 is the rear projection type display device according to any one of claims 1 to 3, wherein the light valves are reflection type light valves 110R, 110G, 11
It is characterized by being 0B. (5) The invention according to claim 5 is the rear projection display device according to any one of claims 1 to 3, wherein the light valves are transmissive light valves 120R, 120G, 120.
It is characterized by being B. (6) The invention according to claim 6 is the rear projection display device according to claim 1, wherein the light valve includes a first light valve 120R that modulates the first color light based on the first image signal. , A second light valve 120G (120B) that modulates the second color light based on the second image signal, and color-separation optical systems 105 and 108 that perform color separation of the illumination light into the first color light and the second color light. And the first light valve 120R
Modulated light by the second light valve 120G (120
The color separation optical system 111 for color-synthesizing the modulated light by B) is further provided, and the first light valve 120R, the second light valve 120G (120B), and the color separation optical system 10 are provided.
5, 108 and the color combining optical system 111,
It has a rectangular effective area corresponding to the aspect ratio of the image, the short side of the effective area is parallel to the virtual reference plane A, and the long side of the effective area is perpendicular to the virtual reference plane A. It is characterized by being arranged.

In the section of means for solving the above-mentioned problems, the present invention is limited to the embodiments although it is associated with the drawings of the embodiments in order to explain the present invention in an easy-to-understand manner. is not.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. —First Embodiment— FIG. 1 is a perspective configuration diagram showing an optical system of a rear projection display device according to a first embodiment of the present invention. In this description,
An X axis, a Y axis, and a Z axis which are orthogonal to each other are defined, and directions and planes are described using these coordinate axes. The Z-axis is an axis parallel to the vertical line that indicates the direction of gravity, and the direction of this Z-axis is
It is the opposite direction of gravity. The X axis and the Y axis are orthogonal to the vertical line. The rear projection display device is placed on a horizontal plane parallel to the XY plane including the X axis and the Y axis.

In FIG. 1, the rear projection display device has a projection display device section 100, a reflection mirror 200, and a transmission screen 300, and is housed in a casing (not shown). The transmissive screen 300 is held in an opening provided in the housing. The projection display device unit 100 includes a light source 10
1, bending mirror 102, first lens plate 103
, Second lens plate 104, cross dichroic mirror 105, bending mirrors 106 and 107, dichroic mirror 108, and polarization beam splitter 1
09R, 109G and 109B, reflective light valves 110R, 110G and 110B, a cross dichroic prism 111, and a projection lens 112. Among the respective members that form the projection display apparatus unit 100,
Each member other than the light source 101 and the bending mirror 102 is arranged vertically on the virtual reference plane A.

FIG. 2 is a side view of the rear projection type display device as seen from the direction parallel to the X axis in the perspective view of FIG. The housing 400 is a rectangular parallelepiped box member, and has an opening for fitting the transmissive screen 300 in a part of its front surface (right side in FIG. 2). A rectangular transmissive screen 300 is fitted in this opening. Transmissive screen 300
Is perpendicular to the YZ plane and parallel to the XZ plane. The reference plane A described above is (1) the reference plane A is perpendicular to the YZ plane, and (2) the angle α between the reference plane A and the horizontal plane H parallel to the XY plane is, for example, α = 15 degrees. Composed.

In FIG. 2, out of the light flux projected from the projection lens 112, the outermost light ray of the light flux cut along a plane including the optical axis and parallel to the YZ plane is shown. Here, the optical axis means the center of the image projected on the transmission screen 300 and the light valves 110R, 110G and 110.
The axis connecting the center of the light flux passing through B. In the first embodiment, the optical axes are the light valves 110R and 11R.
The center of each of 0G and 110B runs perpendicular to the light valve. The optical axis further passes through the center of the transmissive screen 300 perpendicular to the screen.
As described above, since the reference plane A is inclined 15 degrees with respect to the horizontal plane H, the optical axis emitted from the projection lens 112 is emitted in a direction inclined 15 degrees with respect to the Z axis.

The light flux emitted from the projection lens 112 is reflected by the bending mirror 200, and the transmission screen 3
00 is projected. In order for the optical axis to pass through the center of the transmissive screen 300 at a right angle, it is necessary to set the angle θ between the folding mirror 200 and the XZ plane parallel to the transmissive screen 300 to a specific value. In this case, the following expression (1) is established between α and θ.

## EQU1 ## α = 90-2θ (1) From the above equation (1), when α = 15 degrees, θ = 37.5 degrees is calculated.

Details of the projection type display unit 100 will be described with reference to FIG. FIG. 3 is a plan configuration diagram of the projection display device unit 100 formed on the reference plane A. Light source 101
Is a lamp 101a and a parabolic concave mirror 101
b. The lamp 101a is a vertical lighting ultra high pressure mercury lamp. This lamp 101a is shown in FIG.
As shown in FIG. 5, when the virtual line connecting the tips of the discharge electrodes is arranged so as to match the direction of gravity (Z-axis direction), the lamp is designed to have the longest lamp life. The light source light emitted from the lamp 101a arranged parallel to the Z axis, that is, perpendicular to the XY plane, travels in the Z direction by the concave mirror 101b and is incident on the folding mirror 102.

The light flux of the light source incident on the bending mirror 102 is bent at a right angle so that its optical axis advances in the X-axis direction. The light source luminous flux bent by the folding mirror 102 is incident on the first lens plate 103 and the second lens plate 104. First lens plate 103 and second
The lens plate 104 is vertically arranged on the reference plane A. These lens plates 103 and 104 constitute a separate type fly-eye integrator on the optical axis.

The first lens plate 103 includes a plurality of lenses 10.
Reference numeral 3a is a lens array arranged in a matrix on a plane, and the outer peripheral shape thereof is formed into a substantially square shape. The outer shape of each lens 103a is the light valve 110R,
It has a rectangular shape obtained by proportionally reducing the effective pixel areas of 110G and 110B. As a result of the first lens plate 103 being vertically arranged on the reference plane A, the outer periphery of the square shape of the first lens plate 103 is 15 between the Y axis and the Z axis.
Make an angle of degrees. The outer peripheral shape of each lens 103a also forms an angle of 15 degrees with the Y axis and the Z axis.

Light valves 110R, 110G, 110
The effective pixel area of B will be described. When the aspect ratio of the projected image is, for example, horizontal 16: vertical 9, the effective pixel regions by the light valves 110R, 110G, and 110B and the rectangular shape obtained by proportionally reducing these effective pixel regions also have the ratio of 16: 9. In the first embodiment,
Since the optical axis is bent by the projection lens 112, which will be described later, the rectangular shape of each member disposed on the reference plane A is such that the side horizontal to the reference plane A is the vertical side of the image and the reference plane A is the vertical side.
The side perpendicular to the corresponds to the side of the image.

The second lens plate 104 is also the first lens plate 103.
Similarly to the above, a plurality of lenses 104a is a lens array in which two or more lenses are arranged in a matrix in a plane. The outer peripheral shape of the second lens plate 104 is formed in a substantially square shape. The outer peripheral shape of each lens 104a is the light valves 110R and 110R.
It has a rectangular shape in which the effective pixel area defined by G and 110B is proportionally reduced. The second lens plate 104 includes each lens 104.
It is arranged so that a is located at the focal point of each lens 103a of the first lens plate 103. As a result, the light source light incident on the first lens plate 103 is divided into a plurality of light fluxes corresponding to the number of lenses 103a by the openings defined by the outer shapes of the lenses 103a forming the first lens plate 103. It Each of the divided light beams is condensed on the corresponding lens 104a of the second lens plate 104 to form a bright spot. The light emitted from each bright spot on each lens 104a of the second lens plate 104 becomes a plurality of luminous fluxes and illuminates the light valves 110R, 110G, and 110B in a superimposed manner. As a result, each light valve is illuminated uniformly.

The light source light emitted from the second lens plate 104 is incident on the cross dichroic mirror 105.
The cross dichroic mirror 105 includes a dichroic mirror 105B and a dichroic mirror 105RG that are orthogonal to each other. Dichroic mirror 1
05B and 105RG are arranged vertically on the reference plane A. The dichroic mirror 105B is B (blue)
Has light reflection properties. On the other hand, the dichroic mirror 10
5RG has R (red) light and G (green) light reflection characteristics. The cross dichroic mirror 105 color-separates the incident light source light into a B light and a mixed light of the R light and the G light that travel in directions opposite to each other perpendicular to the incident optical axis.

The folding mirrors 106 and 107 are vertically arranged on the reference plane A, respectively. The color-separated B light is reflected by the bending mirror 106. The B light is further perpendicular to the incident surface of the B light polarization beam splitter 109B, and the B light polarization beam splitter 1
The light is incident on the polarization splitting unit 109B-P of 09B at an incident angle of 45 degrees. Polarization beam splitter 109B
Are arranged so that the polarized light separating portions 109B-P are perpendicular to the reference plane A. Polarization beam splitter 109B
Is polarized and separated into P-polarized light which is transmitted through the polarization separation unit 109B-P and is discarded and S-polarized light which is reflected by the polarization separation unit 109B-P.

The mixed light of R light and G light is reflected by the bending mirror 107 and is incident on the dichroic mirror 108. The dichroic mirror 108 has a reference plane A.
It is placed vertically on top. Dichroic mirror 10
Reference numeral 8 has a characteristic of reflecting G light and transmitting R light, and color-separates the incident mixed light into reflected G light and transmitted R light. In this way, the cross dichroic mirror 105
And the dichroic mirror 108 converts the light source light into B light
A color separation optical system that performs color separation into three primary colors of light of G light and R light is configured.

The color-separated G light is perpendicular to the plane of incidence of the G light polarization beam splitter 109G, and the polarization separation unit 109G- of the G light polarization beam splitter 109G-
It is incident on P at an incident angle of 45 degrees. The polarization beam splitter 109G is arranged so that the polarization separation unit 109G-P is perpendicular to the reference plane A. The polarization beam splitter 109G splits the P-polarized light that passes through the polarization splitting unit 109G-P and is discarded into the S-polarized light that reflects the polarization splitting unit 109G-P.

The color-separated R light is perpendicular to the incident surface of the R light polarization beam splitter 109R, and the polarization splitting unit 109R- of the R light polarization beam splitter 109R.
It is incident on P at an incident angle of 45 degrees. The polarization beam splitter 109R is arranged so that the polarization separation unit 109R-P is perpendicular to the reference plane A. The polarization beam splitter 109R splits the P-polarized light that passes through the polarization splitting unit 109R-P to be discarded and the S-polarized light that reflects the polarization splitting unit 109R-P.

Light valves 110B, 110G and 1
The 10Rs are arranged vertically on the reference plane A, respectively. The effective pixel area of each light valve has a rectangular shape. The long side direction is arranged perpendicular to the reference plane A, and the short side direction is arranged parallel to the reference plane A. The S polarized light of B color emitted from the polarization beam splitter 109B for B light is
The light is incident on the reflective light valve 110B. The G-color S-polarized light emitted from the G-light polarization beam splitter 109G is
The light is incident on the reflective light valve 110G. The S polarized light of R color emitted from the polarization beam splitter 109R for R light is
The light is incident on the reflective light valve 110R.

Here, the reflection type light valves 110B, 1
10G and 110R will be described. The reflective light valve is an electric writing reflective light valve.
That is, a plurality of non-linear switching elements such as TFTs are provided on the substrate so as to correspond to pixels, and electrodes for applying a voltage to the liquid crystal layer are connected to the respective TFTs. Further, a liquid crystal layer is formed on each electrode.
Each of these TFTs selectively applies a voltage corresponding to an image signal to the liquid crystal layer. In the liquid crystal layer to which a voltage is applied, the alignment of liquid crystal molecules changes, and the liquid crystal layer comes to function as a phase plate.

The electrode for applying a voltage to the liquid crystal layer also functions as a reflector for reflecting the light incident from the liquid crystal layer side.
The S-polarized light that is incident from above the liquid crystal layer on the region of the liquid crystal layer to which the voltage of the reflective light valve is applied is guided to the reflector through the liquid crystal layer. The reflected light reflected by the reflector is emitted again through the liquid crystal layer. As described above, since the liquid crystal layer to which the voltage is applied functions as a phase plate, the reflected light emitted from the reflective light valve is P-polarized modulated light having a vibration direction different from that of the incident S-polarized light. On the other hand, the S-polarized light incident on the liquid crystal layer in the portion corresponding to the non-selected pixel of the reflective light valve, that is, in the area where the TFT is not applied with voltage proceeds according to the twisted structure of the initial alignment of the liquid crystal molecules. Is reflected by the reflector. The reflected light travels in the opposite direction again according to the twisted structure, and is emitted as S-polarized light having the same vibration direction as the incident S-polarized light. In this way, the reflected light emitted from the reflective light valve is a mixed light composed of the P-polarized light that is the modulated light and the S-polarized light that is the non-modulated light.

The B-color light reflected and emitted from the light valve 110B for B light is re-incident on the polarization beam splitter 109B and is transmitted through the polarization separation unit 109B-P and the P-polarized modulated light and the polarization separation unit 109B-P. The S-polarized non-modulated light that is reflected is polarized and separated. Polarizing beam splitter 10
The non-modulated light reflected by 9B advances toward the light source 101 and is discarded. Similarly, a light valve 110G for G light
The G-color light reflected and emitted from the polarization beam splitter 109
The light is incident on G again, and is polarized and separated into P-polarized modulated light that passes through the polarization splitting unit 109G-P and S-polarized unmodulated light that reflects off the polarization splitting unit 109G-P. Further, the R color light reflected and emitted from the R light light valve 110R is incident again on the polarization beam splitter 109R, and the polarization splitting unit 1
P-polarized modulated light that transmits 09R-P and the polarization splitting unit 1
The polarized light is separated into S-polarized non-modulated light that reflects 09R-P. As a result, the non-modulated light of each color travels toward the light source 101 and is discarded.

The cross dichroic prism 111 is
It is a composite prism member in which the R light reflection dichroic film 111R and the B light reflection dichroic film 111B are arranged so as to be orthogonal to each other. The cross dichroic prism 111 includes the dichroic films 111R,
111B is vertically arranged on the reference plane A. The P-polarized light (modulated light) that has passed through the polarization beam splitter 109B for B light, that is, the analysis light is incident on the cross dichroic prism 111. Similarly, the P-polarized light (modulated light) transmitted through the G-light polarization beam splitter 109G and the P-polarized light (modulated light) transmitted through the R-light polarization beam splitter 109R are respectively incident on the cross dichroic prism 111. .

The R color analysis light incident on the cross dichroic prism 111 is reflected by the R light reflecting dichroic film 11.
It is reflected to the projection lens 112 side by 1R. Also,
The B-color analysis light incident on the cross dichroic prism 111 is reflected toward the projection lens 112 by the B-light reflection dichroic film 111B. Further, the G-color analysis light incident on the cross dichroic prism 111 is
The light passes through both dichroic films 111B and 111R and proceeds to the projection lens 112 side. As a result, the R, G, and B color analysis lights are transmitted to the cross dichroic prism 111.
Is emitted as color-combined light from the same surface. Thus, the cross dichroic prism 111 constitutes a color combining optical system.

The projection lens 112 has a mirror 112m (FIG. 1) inside so as to bend the optical axis at a right angle inside. That is, in the first embodiment, the projection lens 1
The incident optical axis incident on 12 is parallel to the X axis. Also,
The emission optical axis emitted from the projection lens 112 is perpendicular to the incident optical axis and perpendicular to the reference plane A. That is, the emission optical axis of the projection lens 112 is parallel to the YZ plane and has a tilt of 15 degrees with respect to the Z axis.

The projection image emitted from the projection lens 112 is bent by the bending mirror 200 and projected on the transmission screen 300. As a result, a full-color image is formed on the transmissive screen 300. The transmissive screen 300 is parallel to the XZ plane. Screen 300
The long side of the screen of is parallel to the X axis, and the short side of the screen of the screen 300 is parallel to the Z axis. The projection lens 11
2 is adjusted so that the image transmitted through the transmission screen 300 is not distorted.

According to the first embodiment described above,
The following effects can be obtained. (1) Of the members constituting the projection type display device unit 100, members other than the light source 101 and the folding mirror 102 (fly eye integrators 103 and 104, color separation optical systems 105 and 108, polarization separation and light analysis colors). Polarizing beam splitters 109B, 109G, 10 for each light
9R, reflective light valves 110B and 11 for each color light
0G, 110R, color combining optical system 111) as virtual reference plane A
Since the members are arranged vertically above, it is easier to adjust the optical axis and the like as compared with the case where the members are separately arranged on a plurality of different reference planes. (2) Since the light from the light source 101 is guided onto the reference plane A by the bending mirror 102, the discharge direction of the lamp 101a of the light source 101 is matched with the direction of gravity regardless of the direction of the reference plane A ( Parallel to the Z-axis). As a result, a vertical lighting type lamp can be used as the lamp 101a, and the lamp life can be extended. (3) The bending mirror 102 bends the optical axis of the light flux of the light source traveling in the Z-axis direction at a right angle so as to travel on the reference plane A in the X-axis direction. The projection lens 112 has a mirror 112m inside, bends an incident optical axis parallel to the X axis at a right angle, and emits the light toward a bending mirror 200 at an optical axis perpendicular to the incident optical axis and perpendicular to the reference plane A. To do. As a result, the height of the projection display apparatus unit 100 in the Z-axis direction can be suppressed, so that the apparatus can be downsized. (4) The reference plane A is inclined so as to form an angle of α = 15 degrees with the XY plane perpendicular to the direction of gravity. X parallel to the folding mirror 200 and the transmission screen 300
The angle θ with the Z plane is θ =
Set to 37.5 degrees. As a result, α = 0 degree (θ = 45
The projection length of the bending mirror 200 on the Y axis can be shortened as compared with the case of (degree), so that the device can be downsized. (5) Regarding the first lens plate 103 and the second lens plate 104 that form the fly-eye integrator, the plurality of lenses 103a that form the first lens plate 103 arranged in a matrix form the light valves 110R and 110R, respectively.
It has a rectangular shape in which the effective pixel area by G and 110B is proportionally reduced. Since the first lens plate 103 and the second lens plate 104 are arranged vertically on the reference plane A, the light valves 110R, 110G, and 110 are arranged.
B can be efficiently illuminated. (6) Since the optical axis is bent by the projection lens 112, the rectangular shape of each member arranged on the reference plane A is
A side horizontal to the reference plane A corresponds to a vertical side of the image, and a side vertical to the reference plane A corresponds to a horizontal side of the image. In general, since the projected image is horizontally long, the mounting area of each member on the reference plane A can be reduced. As a result, the dichroic prism and the like can be downsized, and the device can be downsized and the cost can be reduced.

In the above description, an example in which the angle α = 15 degrees between the reference plane A and the XY plane perpendicular to the direction of gravity has been described. The value of the angle α may be appropriately determined in consideration of the inclination θ of the folding mirror 200 within the range of 0 <α <45 degrees.

Further, in the above description, the fly-eye integrator using the first lens plate 103 and the second lens plate 104 is used for performing uniform illumination, but a rod integrator may be used as another method. . The rod integrator uses a glass rod whose cross-sectional shape is proportional to the rectangular shape which is the effective pixel area of the light valve. Also in this case, when the rod integrator is arranged on the reference plane A,
Of the rectangular sides of the cross section of the rod integrator, the long sides are arranged perpendicular to the reference plane A and the short sides are arranged horizontally on the reference plane A.

Since the reference plane A used in the above description is a virtual plane provided for the sake of easy understanding, it does not necessarily have to be provided in an actual device.

Second Embodiment In the first embodiment, the incident angle of the axis passing through the center of the transmissive screen 300 is perpendicular to the screen 300, but the incident angle is not perpendicular to the screen 300. May be.
FIG. 4 is a side view of the rear projection display device according to the second embodiment. The same members as those in the side view of FIG. 2 according to the first embodiment are designated by the same reference numerals and the description thereof will be omitted.
In FIG. 4, the axis passing through the center of the transmissive screen 300 is incident at an incident angle β. That is, the angle θ2 between the folding mirror 200 and the XZ plane parallel to the transmission screen 300 has a larger value than the angle θ according to the first embodiment. In this case, the reference plane A and XY
The following expression (2) is established between the angle α2, the angle θ2, and the incident angle β with the horizontal plane H parallel to the plane.

## EQU00002 ## .alpha.2 = 90-2.theta.2. ± ..beta. (2) The sign of. ± ..beta. Is the normal line when the incident optical axis to the screen 400 is downward from the horizontal direction as shown in FIG. The incident angle β of β (β is 0 or a positive value) is + β.
Further, the sign of ± β indicates that the incident angle β with the normal line (β is 0 or a positive value) is −β when the incident optical axis on the screen 400 is incident above the horizontal direction.

According to the second embodiment described above,
In addition to the same effect as the first embodiment, the depth of the rear projection display device (Y-axis direction in the drawing) can be reduced.

-Third Embodiment- In the third embodiment, a transmissive light valve is used instead of the reflective light valve. FIG. 5 is a perspective configuration diagram showing an optical system of a rear projection display device using a transmissive light valve. 5, the same components as those in the perspective configuration diagram of FIG. 1 according to the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The rear projection type display device includes a projection type display device section 100B, a reflection mirror 200, and a transmission screen 30.
0, and is housed in a casing (not shown). The projection display unit 100B includes a light source 101 and a folding mirror 102.
, First lens plate 103, second lens plate 104, cross dichroic mirror 115, and bending mirror 1
16 to 119 and a transmissive light valve 120B, 1
It has 20R and 120G, a cross dichroic prism 121, and a projection lens 112. Among the members constituting the projection display apparatus 100B, the members other than the light source 101 and the bending mirror 102 are arranged vertically on the virtual reference plane A.

XY perpendicular to the reference plane A and the direction of gravity
The angle α between the plane and the angle θ between the folding mirror 200 and the XZ plane parallel to the transmission screen 300 are the same as those in the first embodiment.

The light source luminous flux incident on the bending mirror 102 is bent at a right angle so that its optical axis advances in the X-axis direction. The light source luminous flux bent by the folding mirror 102 is incident on the first lens plate 103 and the second lens plate 104. First lens plate 103 and second
The lens plate 104 includes light valves 120B and 1 to be described later.
Each of 20R and 120G is uniformly illuminated.

The light source light emitted from the second lens plate 104 is incident on the cross dichroic mirror 115.
The cross dichroic mirror 105 includes a dichroic mirror 115B and a dichroic mirror 115R which are orthogonal to each other. Dichroic mirror 11
5B and 115R are arranged vertically on the reference plane A. The dichroic mirror 115B has a B (blue) light reflection characteristic. On the other hand, dichroic mirror 105R
Has an R (red) light reflection characteristic. The cross dichroic mirror 115 color-separates the incident light source light into B light and R light that travel in mutually opposite directions perpendicular to the incident optical axis and G light that passes through the cross dichroic mirror 115. In this way, the cross dichroic mirror 11
5 is a light source light, which is a light beam composed of B light, R light, and G light.
A color separation optical system that separates the primary colors is constructed.

The folding mirrors 116 to 119 are arranged vertically on the reference plane A, respectively. The color-separated B light is reflected by the bending mirrors 116 and 118, and enters the transmissive light valve 120B. The color-separated R light is reflected by the bending mirrors 117 and 119 and is incident on the transmissive light valve 120R. Color-separated G light is transmitted through the light valve 120G.
Is incident on.

Light valves 120B, 120R, 120
Each G is arranged vertically on the reference plane A. The effective pixel area of each light valve has a rectangular shape. The long side direction is arranged perpendicular to the reference plane A, and the short side direction is arranged parallel to the reference plane A. Light valve 120
The light of each color modulated by each of B, 120R, and 120G is color-synthesized by the cross dichroic prism 121, and projected onto the folding mirror 200 by the projection lens 112. The folding mirror 200 reflects the projection light to form a full-color image on the transmissive screen 300.

In the projection display device using the transmissive light valve according to the third embodiment described above, the life of the light source is extended and the device is downsized, as in the first embodiment. It will be possible.

As with the second embodiment, a method in which the incident angle is not right with respect to the transmissive screen 300 may be adopted for the third embodiment. In this case, a rear projection display device having a small depth (Y-axis direction) can be provided.

In the first to third embodiments described above, the case where a plurality of light valves are provided has been described as an example, but the present invention can also be applied to a single plate type projection display device. .

Correspondence between each component in the claims and each component in the embodiment of the invention will be described. The Z-axis direction corresponds to the gravity direction. Bending mirror 102, first lens plate 103, and second lens plate 1
Reference numeral 04 corresponds to the illumination optical system. Reflective light valve 1
10R, 110G and 110B (transmissive light valves 120R, 120G and 120B) correspond to the light valves. The projection lens 112 corresponds to the projection optical system. The folding mirror 200 corresponds to the reflection optical system.
The horizontal plane H corresponds to the plane orthogonal to the direction of gravity. Angle α
Corresponds to the inclination of the reference plane. The cross dichroic mirror 105 and the dichroic mirror 108 (cross dichroic mirror 115) correspond to the color separation optical system. Cross dichroic prism 111 (121)
Corresponds to the color combining optical system.

[0047]

According to the present invention, in a rear projection display device in which a light beam modulated by a light valve is bent and emitted, and the emitted light is reflected by a reflection optical system to project an image on a transmission screen. The light valve is arranged so that the virtual reference plane that is perpendicular to the bulb and that includes one side of the light bulb makes a predetermined angle α with respect to the plane orthogonal to the direction of gravity, and the tip of the discharge electrode is The light beam from the light source, in which the connecting straight line is aligned with the direction of substantially gravity, is bent to illuminate the light valve. This allows the device to be miniaturized while using a long-life lamp.

[Brief description of drawings]

FIG. 1 is a perspective configuration diagram showing an optical system of a rear projection display device according to a first embodiment of the present invention.

FIG. 2 is a side view of the rear projection display device seen from a direction parallel to the X axis in the perspective configuration diagram of FIG.

FIG. 3 is a plan configuration diagram of a projection type display device unit configured on a reference surface.

FIG. 4 is a side view of a rear projection display device according to a second embodiment.

FIG. 5 is a perspective configuration diagram showing an optical system of a rear projection type display device using a transmissive light valve.

FIG. 6 is a cross-sectional view of a conventional rear projection display device viewed from the side.

[Explanation of symbols]

101 ... Light source, 102,200
… Bending mirror, 103… First lens plate,
104 ... Second lens plate, 105, 115 ... Cross dichroic mirror, 106, 107, 116 to 11
9 ... Bending mirror, 108 ... Dichroic mirror,
109R, 109G, 109B ... Polarizing beam splitter,
110R, 110G, 110B ... Reflective light valve, 1
11,121 ... Cross dichroic prism, 112
... Projection lens, 120R, 120G, 120B ... Transmissive light valve, 300 ... Transmissive screen, 4
00 ... Case

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H099 AA11 BA09 BA17 CA02 CA07                       CA11                 5C058 BA29 EA01 EA12 EA13 EA42                       EA51                 5C060 GA01 GB02 GB04 HC19 HC21

Claims (6)

[Claims] 1. A light source for supplying illumination light by aligning a straight line connecting the tips of discharge electrodes with a substantially gravitational direction, an illumination optical system for bending and emitting a light beam from the light source, and a rectangular shape. A light valve that modulates the illumination light from the illumination optical system based on an image signal; a projection optical system that bends and outputs the modulated light flux from the light valve; and a reflection that reflects the light flux emitted from the projection optical system. An optical system and a transmissive screen onto which an image of the reflected light flux from the reflective optical system is projected, and a virtual reference plane that is a surface perpendicular to the light valve and includes one side of the light valve is the direction of gravity. A rear projection display device, wherein the light valve is arranged so as to form a predetermined angle α with respect to a surface orthogonal to the surface. 2. The rear projection display device according to claim 1, wherein the illumination optical system includes an integrator that uniformly illuminates the light valve, and the integrator is arranged according to an inclination of the light valve. And a rear projection display device. 3. The rear projection display device according to claim 1, wherein the transmissive screen is arranged parallel to the direction of gravity, and an angle θ between a plane parallel to the transmissive screen and the reflective optical system. And a predetermined angle α and an incident angle β at which the axis passing through the center of the reflected light beam enters the transmission screen, α = 90-2θ ± β. Display device. 4. The rear projection display device according to claim 1, wherein the light valve is a reflective light valve. 5. The rear projection display device according to claim 1, wherein the light valve is a transmissive light valve. 6. The rear projection display device according to claim 1, wherein the light valve includes a first light valve that modulates a first color light based on a first image signal and a second image signal. A second light valve that modulates a second color light based on the first light valve, and a color separation optical system that color-separates the illumination light into the first color light and the second color light. And a color combining optical system for color combining the modulated light by the second light valve, the first light valve, the second light valve, the color separating optical system, and the color combining optical. Each of the systems has a rectangular effective area corresponding to the aspect ratio of the image, the short side of the effective area is parallel to the virtual reference plane, and the long side of the effective area is the virtual side. To be perpendicular to the reference plane A rear projection type display device characterized in that the rear projection type display device is arranged.