JP2001013588A - Illuminating optical system and projection type display device using thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique to miniaturize a projection type display device. SOLUTION: This device is provided with an illuminating optical system to emit illuminating light, electric optical devices 300R, 300G and 300B to generate a modulated light beam flux by modulating the illuminating light in accordance with picture information and a projecting optical system 340 to project the modulated light beam flux. Also, the illuminating optical system is provided with a light source device 100 to emit a nearly parallel light beam flux and light guiding parts 250R, 250G and 250B to nearly uniformize the intensity distribution of the light of a light beam flux emitted by the light source device 100. The light guiding parts 250R, 250G and 250B possess a light incident plane on which the light emitted by the light source device 100 is made incident, a light-emitting surface to emit the light made incident from the light incident plane and a diffusing part provided between the light incident plane and the light-emitting surface and to diffuse the light, and also has a stereoscopic shape having the light incident plane and the light-emitting surface as a bottom surface. The illuminating optical system is miniaturized when the illuminating optical system thereof is used, so that the projection type display device is miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a projection display device for projecting and displaying an image.

[0002]

2. Description of the Related Art In a projection display device, illumination light emitted from an illumination optical system is modulated according to image information (image signal) using a liquid crystal panel or the like, and the modulated light is projected on a screen. This realizes image display. As an illumination optical system, a light source device using a high-pressure discharge lamp and a so-called integrator optical system are generally used. The integrator optical system includes a lens array and a superimposing lens, divides a light beam emitted from the light source device using the lens array, and superimposes the divided light beam using the superimposing lens to thereby generate light. This is to make the intensity distribution uniform.

[0003]

In recent years, there has been a demand for a reduction in the size of a projection display device. However, in the conventional projection display device, the illumination optical system including the integrator optical system occupies a large volume in the projection display device, so that there is a problem that miniaturization is difficult.

[0004] The present invention has been made to solve the above-mentioned problems in the prior art, and has as its object to provide a technique capable of reducing the size of an illumination optical system and a projection display device using the same. And

[0005]

In order to solve at least a part of the above-mentioned problems, an illumination optical system according to the present invention comprises a light source device that emits a substantially parallel light beam, and a light source device that emits a substantially parallel light beam. A light guide for substantially uniforming the intensity distribution of the light of the emitted light beam, wherein the light emitted from the light source device is incident on the light guide. A light incident surface, a light exit surface for emitting light incident from the light incident surface, and a diffusing unit for diffusing light provided between the light incident surface and the light exit surface,
It has a three-dimensional shape having the light incident surface and the light exit surface as bottom surfaces.

[0006] The illumination optical system of the present invention includes a light source device for emitting a substantially parallel light beam, and a light guide for uniformizing the intensity distribution of light emitted from the light source device. With such an illumination optical system, the size can be considerably reduced as compared with an illumination optical system including a conventional integrator optical system. When such an illumination optical system is applied to a projection display device, the projection display device can be downsized.

In this specification, the “three-dimensional shape having a light incident surface and a light exit surface as bottom surfaces” means a three-dimensional shape having a light incident surface and a light exit surface as two bottom surfaces, an upper bottom surface and a lower bottom surface. Means shape.

[0008] In the above illumination optical system, it is preferable that the diffusing portion is a polished surface.

With this configuration, the light incident on the light guide can be easily diffused, so that light having a substantially uniform intensity distribution can be emitted from the light guide.

[0010] In the illumination optical system described above, the diffusing section may be a diffraction grating.

Alternatively, in the above-mentioned illumination optical system, the diffusing section may be a lens array including a plurality of lenses.

As described above, even when a diffraction grating or a lens array is used as the diffusing portion, the light incident on the light guiding portion can be diffused, so that light having a substantially uniform intensity distribution is emitted from the light guiding portion. can do.

In the above illumination optical system, it is preferable that a reflection film for reflecting light traveling in the light guide is formed on a side surface of the light guide.

With this configuration, it is possible to prevent a part of the light diffused by the diffusing portion from being emitted from the side surface of the light guiding portion, so that light having higher intensity is emitted from the light guiding portion. It is possible to eject from the surface.

According to another aspect of the invention, there is provided a projection display apparatus, comprising: an illumination optical system according to any one of the above; an electro-optical device that modulates the illumination light in accordance with image information to generate a modulated light beam; A projection optical system for projecting the modulated light beam, wherein the light source device collects the light emitted from the light source lamp by reflecting the light emitted from the light source lamp. A reflector having a spheroidal reflecting surface for emitting light, and a collimating lens for collimating the light reflected by the reflecting surface of the reflector, and emitted from the collimating lens. It is preferable that the cross-sectional shape of the light beam is adjusted to a size that is included in the light incident surface of the light guide.

In this projection display device, the illumination optical system as described above is used, so that the illumination optical system can be downsized. As a result, the projection display device can be downsized. Becomes In the illumination optical system,
When the light source device as described above is used, all the light beams emitted from the light source device can be made incident on the light guide portion, so that light can be used effectively.

In the above-mentioned projection type display device, the electro-optical device includes a substantially rectangular modulation region for modulating the illumination light, and the light exit surface of the light guide section is It is preferable to have a substantially rectangular shape larger than the modulation area by a predetermined width.

Alternatively, in the above-mentioned projection type display device, the electro-optical device includes a substantially rectangular modulation region for performing the modulation of the illumination light, and the light exit surface of the light guide unit has a light exit surface. , And may have a shape that encompasses the modulation region and substantially circumscribes the modulation region.

With this configuration, the light emitted from the light guide can be reliably incident on the modulation area. Further, in the modulation region, it is possible to effectively use the light emitted from the light guide.

In the above-mentioned projection display device, the light incident surface and the light exit surface of the light guide may be set to have substantially the same shape.

In this case, it is possible to easily manufacture the light guide portion having the light entrance surface and the light exit surface having different shapes.

Alternatively, in the above-mentioned projection display device, the light entrance surface and the light exit surface of the light guide section are set such that the light entrance surface is set larger than the light exit surface. Is also good.

As described above, even when the light incident surface of the light guide portion is larger than the light exit surface, it is possible to emit light having a substantially uniform intensity distribution from the light exit surface.
Also, when the cross-sectional shape of the substantially parallel light beam emitted from the light source device is relatively large, a relatively large light incident surface suitable for the cross-sectional shape of the light beam emitted from the light source device and the modulation of the electro-optical device If a light guide having a relatively small light exit surface suitable for the size of the region is prepared, the light guide can be matched to the modulation regions of the light source device and the electro-optical device.

In the above projection display device, the cross-sectional shape of the opening of the reflector, the shape of the light incident surface of the light guide, and the shape of the light exit surface of the light guide are controlled by the modulation. The area may be set to be substantially similar to the area.

In the case where a reflector having a sectional shape substantially similar to that of the modulation region is used, the sectional shape of a substantially parallel light beam emitted from the light source device is also substantially similar to that of the modulation region. At this time, as described above, if the cross-sectional shape of the opening of the reflector, the shape of the light incident surface and the shape of the light exit surface of the light guide are all similar to the modulation region, the light source device and the light guide The part can be aligned with the modulation area of the electro-optical device.

[0026]

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is an explanatory diagram showing a projection display device to which the present invention is applied. This projection display device includes a light source device 100, three light guides 250R, 250G, 250B, three liquid crystal light valves 300R, 300G, 300B, a cross dichroic prism 320, and a projection lens 340. I have. This device also includes two dichroic mirrors 201 and 202 for guiding the light emitted from the light source device 100 to the three light guides 250R, 250G and 250B.
And three reflecting mirrors 203, 204, 205.

Light emitted from the light source device 100 is separated into three color lights of red (R), green (G), and blue (B) by two dichroic mirrors 201 and 202. Each of the separated color lights is provided as a light guide 250R, 250G,
After passing through the liquid crystal light valve 300R,
The light enters 300G and 300B. Liquid crystal light valve 30
Each of 0R, 300G, and 300B modulates the incident color light according to image information. Each modulated color light (modulated light beam)
Are synthesized by the cross dichroic prism 320,
An image is displayed by projecting the combined light on the screen SC by the projection lens 340.

The light source device 100 includes a light source lamp 102,
A reflector 104 and a parallelizing lens 106 are provided. The center of each optical element 102, 104, 106 is
00ax. The axis 100ax is
It coincides with the central axis of the light beam emitted from the light source device 100.

FIG. 2 is an explanatory diagram showing the light source device 100 in an enlarged manner. In FIG. 2, for convenience, the light source lamp 10 is used.
2 (FIG. 1) is omitted, and the center 102c of the light source lamp is shown. Here, the center 1 of the light source lamp
02c means the center of the arc generated between the electrodes of the light source lamp 102.

The light source lamp 102 is located at the center 1 of the light source lamp.
Light is emitted radially from 02c. FIG. 2 illustrates the trajectory of the light beam emitted from the center 102c of the light source lamp. Light radially emitted from the center 102c of the light source lamp is reflected by the reflector 104. In addition,
As the light source lamp, a high-pressure discharge lamp such as a metal halide lamp or a high-pressure mercury lamp is used.

The reflector 104 is an elliptical reflector having a reflection surface 104R formed of a spheroid symmetrical about the axis 100ax. The spheroid is formed using, for example, glass. A dielectric multilayer film is formed on the reflection surface 104R. Note that a metal reflection film such as an aluminum film or a silver film may be formed on the reflection surface 104R.

The center 102c of the light source lamp is positioned between the two focal points FR on the axis 100ax of the elliptical reflector 104.
1 and FR2, it is arranged at the position of the focus (first focus) FR1 closer to the elliptical reflector 104. The light emitted from the light source lamp 102 is the elliptical reflector 1
The light is reflected by the light source 04 and goes to the other focal point (second focal point) FR2 of the elliptical reflector 104. The light traveling while being collected in the direction of the second focal point FR2 enters the collimating lens 106.

The collimating lens 106 is an elliptical reflector 1
It has a function of converting the reflected light reflected by the light into substantially parallel light. The collimating lens 106 shown in FIG.
The entrance surface 106i has a flat surface, and the exit surface 106o has a spheroidal aspheric surface. Exit surface 106o
Is set such that the light incident on the collimating lens 106 is effectively converted into parallel light. As shown in FIG. 2, the parallelizing lens 106 is provided at a position relatively far from the elliptical reflector 104. By arranging the collimating lens 106 at such a position, the light traveling while being collected by the elliptical reflector 104 can be collimated. Therefore, the width of the light beam emitted from the collimating lens 106 is relatively small. It is possible to set.

The exit surface 106 of the collimating lens 106
o may be a spherical surface instead of an aspheric surface. Again,
Light incident on the collimating lens can be made substantially parallel light. However, using a collimating lens having an aspheric surface as shown in FIG. 2 has an advantage that a light beam with higher parallelism can be obtained. The incident surface 106i may be a spherical surface instead of a plane. This makes it possible to emit a light beam with higher parallelism.

R, G, B emitted from the light source device 100
The light including the color components of the above is separated into three color lights of R, G, and B via the two dichroic mirrors 201 and 202 in FIG. Specifically, the first dichroic mirror 2
Numeral 01 separates the incident light into red light R and light containing green and blue color components G and B. The second dichroic mirror 202 further separates the light containing the separated green and blue color components G and B into green light G and blue light B. The separated red light R is guided to the reflection mirror 203 and enters the light guide 250R. The green light G directly enters the light guide 250G. The blue light B is guided to the two reflection mirrors 204 and 205 and enters the light guide 250B.

Since the light emitted from the light source device 100 is a substantially parallel light beam as described above, the dichroic mirrors 201 and 202 and the reflection mirror 20 are not used.
After passing through 3, 204 and 205, three light guides 250R and 25
Light incident on 0G and 250B is also a substantially parallel light beam. Further, the cross-sectional shape of the light beam L1i incident on the light guide 250G is the same as the cross-sectional shape of the light beam emitted from the light source device 100 (FIG. 2). The cross-sectional shape of the light beam will be described later.

FIG. 3 shows the three light guides 250R, 2 of FIG.
It is explanatory drawing which shows one light guide part 250G among 50G and 250B. FIG. 3A is a perspective view of the light guide 250G, and FIG. 3B is a plan view of the light guide 250G when viewed from the −X direction.

The light guide section 250G has a substantially square incident surface 25.
It has a substantially columnar outer shape with 0 Gi and the emission surface 250Go as bottom surfaces. The light guide section 250G includes two transparent bodies 251a and 251b such as glass transparent to visible light.
A diffusion part 252 is provided between the two. Light guide 2
On the side surface of 50G, a reflection film 250Gr for reflecting light traveling in the light guide 250G is formed. The reflection film 250Gr is formed of a dielectric multilayer film, a metal film, or the like.

The diffusing portion 252 has a function of diffusing substantially parallel light beams incident from the incident surface 250Gi.
As can be seen from the distribution of the trajectories of the light rays shown in FIG. 2, the light emitted from the light source device 100 has a relatively high light intensity near the axis 100ax, and has a relatively high light intensity away from the axis 100ax. It is getting smaller. The shaft 100a
Since the electrodes of the light source lamp 102 and the like exist on x and become a shadow when light is emitted, actually, the axis 100ax
The intensity of the light in the vicinity of is extremely small. When light having such an uneven intensity distribution is directly incident on the liquid crystal light valves 300R, 300G, and 300B (FIG. 1), unevenness in brightness and darkness occurs in an image displayed on the screen SC. As shown in FIG. 3B, the diffusing unit 252 diffuses light having a non-uniform intensity distribution to make the intensity distribution of light emitted from the light guiding unit 250G substantially uniform. The light diffused by the diffusion unit 252 is reflected by the reflection film 250 formed on the side surface of the light guide unit 250G.
Reflected at least once by Gr, or not reflected,
Proceed to the exit surface 250Go. In this way, the emission surface 250
Since the intensity distribution of the light reaching Go is almost uniform, it is possible to reduce the unevenness of the brightness of the image displayed on the screen SC.

In this embodiment, the diffusion portion 252 is formed by a polished surface. The polished surface is formed, for example, by polishing at least one contact surface of the two transparent bodies 251a and 251b with gold sand or the like. After the polished surface is formed, the two transparent bodies 251a and 251b are brought into contact with each other, and then the reflective film 250Gr is formed on the side surface. Or,
A reflection film 250Gr is formed on each side surface of the two transparent bodies 251a and 251b, and the two transparent bodies 251a and 251b are brought into mechanical contact with each other.

Further, the diffusing portion 252 can be formed by a diffraction grating or a microlens array. The micro lens array is a lens group in which a plurality of minute lenses are arranged. As described above, even if a diffraction grating or a lens array is used, it is possible to diffuse an incident substantially parallel light beam.

In the present embodiment, the diffusing section 252 is
Although it is provided at a position relatively close to the incident surface 250Gi within 50G, generally, the diffusing portion 252 is
What is necessary is just to be provided between i and the emission surface 250Go.
When the diffusion portion 252 is provided at a position relatively close to the incident surface 250Gi as in the present embodiment, the number of times light is reflected inside the light guide portion 250G can be increased, so that a more uniform intensity distribution can be obtained. There is an advantage that it is highly possible to emit the light having the light. In this case, the light guide 250
Since the length L of G can be set relatively small,
There is also an advantage that the projection display device can be further reduced in size.

Although the light guide 250G of this embodiment has the reflective film 250Gr formed on the side surface, the reflective film may be omitted. Also in this case, it is possible to emit light having a substantially uniform intensity distribution. However, if the reflective film 250Gr is provided as in the present embodiment, it is possible to prevent a part of light incident at an incident angle smaller than the critical angle from being emitted to the outside from the side surface of the light guide 250G. Thus, light with higher intensity can be emitted from the emission surface 250Go.

FIG. 4 is an explanatory diagram showing a cross-sectional shape of a light beam incident on the light guide 250G and a cross-sectional shape of a light beam emitted from the light guide 250G.

FIG. 4A shows the incident surface 2 of the light guide 250G.
The cross-sectional shape of the light beam L1i incident on 50 Gi is shown. As shown in FIG. 4A, the substantially parallel light beam L1i incident on the light guide 250G has a substantially circular cross-sectional shape. This is because, in the light source device 100 (FIG. 2), the cross-sectional shape of the opening of the elliptical reflector 104 is substantially circular. As shown in the drawing, the cross-sectional shape of the light beam L1i incident on the light guide 250G, in other words, the cross-sectional shape of the light beam emitted from the light source device 100 is different from that of the light guide 25.
The size is adjusted so as to be included in a substantially square entrance surface 250Gi of 0G. In this embodiment,
The cross-sectional shape of the substantially parallel light beam emitted from the light source device is adjusted to a size such that the cross-sectional shape is included in the incident surface of the light guide unit. May be adjusted to include the size. However, according to the present embodiment, all substantially parallel light beams emitted from the light source device 100 can be made incident on the light guide 250G, so that light can be used effectively.

FIG. 4B shows the light exit surface 2 of the light guide 250G.
The cross-sectional shape of the light beam L1o emitted from 50Go is shown. In FIG. 4B, the liquid crystal light valve 30
OG (FIG. 1) is also shown. As shown in FIG. 4B, the cross-sectional shape of the light beam L1o emitted from the light guide 250G has a substantially square shape. This is the light guide 2
This is because the shape of the 50G emission surface 250Go is substantially square. That is, the substantially parallel light beam L1i incident from the incident surface 250Gi is diffused by the diffusion unit 252 when passing through the light guide unit 250G, and further,
The light is reflected by the reflection film 250Gr. Through this process, the light beam L1 emitted from the light guide portion 250G
The cross-sectional shape of “o” is substantially the same as the shape of the emission surface 250Go.

The liquid crystal light valve 300G is shown in FIG.
As shown in the figure, the effective display area EA is included. The effective display area EA is a modulation area for modulating incident light (illumination light), and has a substantially rectangular shape. As shown in the figure, the emission surface 250Go of the light guide 250G has a substantially rectangular shape that is larger than the effective display area EA by a predetermined width. In this way, the light beam L1o emitted from the emission surface 250Go of the light guide 250G can be surely made incident on the effective display area EA of the liquid crystal light valve 300G.

Although one light guide 250G in FIG. 1 has been described above, the same applies to the other light guides 250R and 250B. The light source device 100 according to the present embodiment
, Two dichroic mirrors 201, 202, 3
The three reflecting mirrors 203, 204, 205 and the three light guides 250R, 250G, 250B correspond to an illumination optical system in the present invention.

The three light guides 250R, 250G, 250
B (FIG. 1) emits three color lights (illumination lights) respectively from three liquid crystal light valves 300R, 300G, and 300.
Illuminate B. Three liquid crystal light valves 300R, 30
0G and 300B modulate the three color lights in accordance with given image information (image signals) to generate modulated light beams. The liquid crystal light valves 300R, 300 of this embodiment
G and 300B each include a liquid crystal panel corresponding to the electro-optical device of the present invention, and polarizing plates disposed on the light incident surface side and the light exit surface side.
Note that the polarizing plate provided on the light incident surface side of the liquid crystal light valve may be provided on the emission surfaces of the three light guides 250R, 250G, and 250B.

The cross dichroic prism 320 is
The modulated light fluxes of the three colors modulated through the liquid crystal light valves 300R, 300G, and 300B are combined to generate combined light representing a color image. In the cross dichroic prism 320, a red light reflecting dichroic surface 321 and a blue light reflecting dichroic surface 322 are formed in an approximately X-shape at the interface between the four right-angle prisms. On the red light reflecting dichroic surface 321, a dielectric multilayer film that reflects red light is formed.
In 22, a dielectric multilayer film that reflects blue light is formed. The three color lights are combined by the red light reflecting dichroic surface 321 and the blue light reflecting dichroic surface 322 to generate combined light representing a color image.

The combined light generated by the cross dichroic prism 320 is emitted toward the projection lens 340. The projection lens 340 projects the combined light emitted from the cross dichroic prism 320 to display a color image on the screen SC. The projection lens 34
As 0, a telecentric lens can be used.

As described above, the projection type display device of this embodiment has, as an illumination optical system, a light source device 100 that emits a substantially parallel light beam and an intensity distribution of light emitted from the light source device 100. A light guide portion 250R for making the light substantially uniform,
250G and 250B. If the illumination optical system has such a configuration, the illumination optical system can be reduced in size, and as a result, the projection display device can be reduced in size.

B. Modification of Light Guide: FIG. 5 is an explanatory view showing a first modification of the light guide shown in FIG. The light guide 260G in FIG. 5 is used instead of the light guide 250G in FIG. Note that, instead of the other light guide units 250R and 250B in FIG. 1, the same light guide unit 260G in FIG. 5 is used.
FIG. 5A is a perspective view of the light guide 260G, and FIG.
(B) is a top view when the light guide part 260G is seen from the -X direction.

The light guide 260G is formed by the light guide 25 shown in FIG.
0G and the outer shape are different. That is, the light guide 250G in FIG. 3 has a substantially columnar outer shape in which the entrance surface 250Gi and the exit surface 250Go have squares of substantially the same size, but the light guide 260G in FIG.
Gi and the shape of the exit surface 260Go are substantially quadrangular pyramid-shaped outer shapes. Specifically, the incident surfaces 250Gi, 260G of the two light guides 250G, 260G in FIGS.
Gi have the same shape, but the emission surfaces 250Go, 260G
The shape of o is different.

FIG. 6 is an explanatory diagram showing a cross-sectional shape of a light beam incident on the light guide 260G of FIG. 5 and a cross-sectional shape of a light beam emitted from the light guide 260G. FIG. 6A shows a light beam L2 incident on the incident surface 260Gi of the light guide 260G.
4A shows a cross-sectional shape, which is the same as FIG.
FIG. 6B shows a cross-sectional shape of the light beam L2o emitted from the emission surface 260Go of the light guide 260G, which is substantially rectangular. This corresponds to the exit surface 26 of the light guide 260G.
This is because the shape of 0Go is substantially rectangular.

As shown in FIG. 6B, the emission surface 260G
o is substantially similar to the effective display area EA of the liquid crystal light valve 300G, and has a substantially rectangular shape larger than the effective display area EA by a predetermined width. By using the light guide 260G having such an exit surface 260Go, most of the light emitted from the light guide 260G can be made to enter the effective display area EA. Therefore, there is an advantage that the light beam L2o emitted from the light guide 260G can be used more effectively than using the light guide 250G (FIG. 4B) having a substantially square exit surface. However, since the outer shape of the light guide section 250G in FIG. 3 is substantially columnar, the light guide section 2 has a substantially conical shape.
There is an advantage that it can be easily manufactured as compared with 60G.

FIG. 7 is an explanatory view showing a second modification of the light guide section shown in FIG. The light guide 270G of FIG. 7 is used instead of the light guide 250G of FIG. It should be noted that the other light guides 250R and 250B in FIG.
The same thing as 0G is used. FIG. 7A is a perspective view of the light guide unit 270G, and FIG.
It is a top view when G is seen from the -X direction. The light guide 270G has a substantially columnar outer shape in which the entrance surface 270Gi and the exit surface 270Go have substantially the same substantially circular shape.

FIG. 8 is an explanatory diagram showing a cross-sectional shape of a light beam incident on the light guide 270G of FIG. 7 and a cross-sectional shape of a light beam emitted from the light guide 270G. FIG. 8A shows a light beam L3 incident on the incident surface 270Gi of the light guide 270G.
The cross-sectional shape of i is shown. Also in this case, similarly to FIG. 4, the light beam L3 incident on the light guide 270G
The cross-sectional shape of i, in other words, the cross-sectional shape of the light beam emitted from the light source device 100 is adjusted to a size that is included in the substantially circular incident surface 270Gi of the light guide 270G. Accordingly, all the substantially parallel light beams emitted from the light source device 100 can be made incident on the light guide 270G, so that the light can be used effectively.

FIG. 8B shows the light exit surface 2 of the light guide 270G.
It shows the cross-sectional shape of the light beam L3o emitted from 70Go, and is substantially circular as shown in the figure. This is because the shape of the exit surface 270Go of the light guide 270G is substantially circular. As shown in FIG.
The shape of the emission surface 270Go is a liquid crystal light valve 300G.
And the effective display area EA
Has a shape substantially circumscribed by Such an emission surface 2
Even if the light guide unit 270G having 70Go is used, the light guide unit 2
The light emitted from 70G can be made to enter the effective display area EA successfully.

FIG. 9 is a perspective view showing a third modification of the light guide shown in FIG. The light guide 280G of FIG. 9 is used instead of the light guide 250G of FIG. It should be noted that the other light guides 250R and 250B in FIG.
The same thing as 0G is used. In this light guide section 280G, the entrance surface 280Gi and the exit surface 280Go have a substantially columnar outer shape having substantially the same substantially rectangular shape. It has a similar shape.

FIG. 4A, FIG. 6A, FIG.
In (A), the cross-sectional shapes of the light beams L1i, L2i, and L3i incident on the light guide portions 250G, 260G, and 270G are all substantially circular. This is because the cross-sectional shape of the light beam emitted from the light source device 100 (FIG. 2) is substantially circular as described above. FIG. 4 (A), FIG.
(A), as shown in FIG. 9, when using the light guide portions 250G and 260G having a substantially rectangular incident surface, the cross-sectional shape of the incident light beam may be substantially rectangular.

FIG. 10 is an explanatory view showing an example of a light source device in the case where the cross-sectional shape of the light beam incident on the light guide is substantially rectangular, and is suitable for the light guide 280G of FIG. This light source device 100 'is different from the light source device 100 of FIG. 1 in the shape of a reflector 104'. In addition,
In FIG. 10, the illustration of the light source lamp is omitted, and only the reflector 104 ′ and the parallelizing lens 106 are illustrated.

FIG. 10A is a plan view when the reflector 104 'is viewed from the + Y direction as in FIG.
0 (B) is a plan view when the reflector 104 ′ is viewed from the −X direction. As shown in FIGS. 10A and 10B, this reflector 104 ′ is obtained by changing the curved surface of the reflection surface 104 R (FIG. 2) near the opening of the reflector 104 to the axis 100.
4 parallel to ax and perpendicular to the X or Y direction
It has a reflecting surface 104R 'replaced by two planes.
The ratio of the length Wx in the X direction of the opening to the length Wy in the Y direction is:
The aspect ratio (the ratio between the height and the width) of the effective display area EA of the liquid crystal light valve is set to be substantially the same. FIG. 10C is a plan view when the reflector 104 ′ is viewed from the + Z direction. As shown in the figure, the shape of the opening of the reflector 104 ′ has a substantially rectangular shape (W
xxWy). Such a reflector 10
The cross-sectional shape of the light beam emitted from 4 ′ is a substantially rectangular shape similar to the effective display area EA of the liquid crystal light valve. For this reason, the cross-sectional shape of the substantially parallel light beam emitted from the light source device 100 ′ after passing through the collimating lens 106 also becomes a substantially rectangular shape similar to the effective display area EA of the liquid crystal light valve. As described above, by using the light source device 100 ′, it is possible to emit a light beam having a cross-sectional shape suitable for the shape of the light guide 280G in FIG.

FIG. 11 shows the cross-sectional shape of the light beam incident on the light guide 280G of FIG. 9 and the cross-sectional shape of the light beam emitted from the light guide 280G when the light source device 100 ′ of FIG. 10 is used. FIG.

FIG. 11A shows a cross-sectional shape of the light beam L4i incident on the incident surface 280Gi of the light guide 280G, which is substantially similar to the shape of the incident surface 280Gi. As described above, the reflector 10 of the light source device 100 ′
By making the cross-sectional shape of the opening 4 ′ substantially rectangular, the light beam L4i having the substantially rectangular cross-sectional shape can be transmitted to the light guide portion 2.
80G. FIG. 11B shows the cross-sectional shape of the light beam L4o emitted from the emission surface 280Go of the light guide 280G, which is substantially the same as the shape of the emission surface 280Go. The shape of the exit surface 280Go is determined by the effective display area EA of the liquid crystal light valve 300G.
And has a substantially rectangular shape larger by a predetermined width than the effective display area EA.

As described above, the entrance surface 280Gi and the exit surface 280Go of the light guide 280G are substantially similar to the effective display area EA of the liquid crystal light valve 300G. The cross-sectional shape of the opening of the reflector 104 'of the light source device 100' is also substantially similar to the effective display area EA of the liquid crystal light valve 300G. By using such a light source device 100 ′ and the light guide 280G, light that matches the effective display area EA of the liquid crystal light valve can be easily obtained.

In FIG. 10, the cross-sectional shape of the opening of the reflector is substantially rectangular similar to the effective display area EA of the liquid crystal light valve, but the cross-sectional shape of the opening of the reflector may be substantially square. The light beam emitted from the light source device having such a reflector is adapted to the light guide having a substantially square incident surface shown in FIGS. 4 (A) and 6 (A).

By the way, the above light source devices 100 and 10
At 0 ′ (FIGS. 1 and 10), the cross-sectional shape of the emitted substantially parallel light beam is adjusted to substantially match the size of the effective display area EA of the liquid crystal light valve. When the size is further reduced, that is, when the distance between the reflector and the parallelizing lens is further reduced, the cross-sectional shape of the emitted substantially parallel light beam increases. In such a case, a light guide unit having an incident surface larger than the exit surface may be prepared, such as the light guide unit 260G shown in FIG. That is, it is necessary to prepare a light guide unit having an incident surface that allows the light beam emitted from the light source device to be incident on the light guide unit and an exit surface suitable for the size of the effective display area EA of the liquid crystal light valve. The light guide can be aligned with the light source device and the effective display area EA.

As described above, the light guide in the present invention generally includes an incident surface on which light emitted from the light source device is incident, an exit surface for emitting light incident from the incident surface,
What is necessary is just to have a diffusion part provided between the entrance surface and the exit surface for diffusing the light, and to have a three-dimensional shape having the entrance surface and the exit surface as bottom surfaces.

C. Modification of Light Source Device: FIG.
FIG. 9 is an explanatory diagram showing a first modification of the light source device shown in FIG. 2. The light source device 110 of FIG. 12 includes a light source lamp (not shown), an elliptical reflector 114, and a parallelizing lens 116. The light source device 110 includes the light source device 100
This is almost the same as (FIG. 2), but the shape of the parallelizing lens 116 is different. That is, the collimating lens 10 of FIG.
6 has an incident surface 106i having a flat surface and an exit surface 10i.
6o has a spheroidal aspherical surface. On the other hand, in the parallelizing lens 116 in FIG. 12, the entrance surface 116i has an aspheric surface having a hyperboloid of revolution, and the exit surface 116o has a flat surface. Even when the light source device 110 having such a parallelizing lens 116 is used, a substantially parallel light beam can be emitted.

The trajectory of the light beam emitted from the light source device 110 shown in FIG. 12 is compared with the trajectory of the light beam emitted from the light source device 100 shown in FIG. The intensity of the emitted light is
It becomes considerably large near x. That is, the light source device 100 of FIG.
A light beam having a more uniform intensity distribution can be emitted. Therefore, when the light source device 100 of FIG. 2 is used, there is an advantage that it is highly likely that the intensity distribution of the light emitted from the light guide unit can be made more uniform.

FIG. 13 is an explanatory view showing a second modification of the light source device shown in FIG. 1 (FIG. 2). Light source device 1 of FIG.
Reference numeral 20 denotes a light beam width adjusting lens 12 including a light source lamp (not shown), a reflector 124, and two plano-convex lenses.
6 is provided. Reflector 1 of light source device 120
Reference numeral 24 denotes a parabolic reflector having a rotational parabolic reflecting surface 124R that is symmetric about the axis 120ax. The center 102c of the light source lamp is disposed at the focal position FR of the paraboloid of revolution, and the light emitted radially from the center 102c of the light source lamp is reflected by the parabolic reflector 124 and then becomes substantially parallel light. It is ejected. The substantially parallel light beam reflected by the parabolic reflector 124 is emitted from the light source device 120 after the light beam width adjustment lens 126 adjusts the light beam width. Such a light source device 12
Even if 0 is used, it is possible to emit a substantially parallel light beam included in the incident surface of the light guide. As can be understood from this description, the light source device in the present invention may be any device that generally emits a substantially parallel light beam.

As can be seen by comparing the trajectory of the light beam emitted from the light source device 120 in FIG. 13 with the trajectory of the light beam emitted from the light source device 100 in FIG. The intensity of the applied light is
It becomes considerably large near x. Therefore, when the light source device 100 of FIG. 2 is used, there is an advantage that it is highly likely that the intensity distribution of the light emitted from the light guide unit can be made more uniform.

Further, in the light source device 120 of FIG. 13, since the light beam width adjusting lens 126 is composed of two plano-convex lenses, a larger volume than the light source device 100 of FIG. 2 and the light source device 110 of FIG. Required. Therefore, using the light source devices 100 and 110 shown in FIGS. 2 and 12 has an advantage that the projection display device can be further reduced in size.

The light source device 11 shown in FIGS.
The cross-sectional shape of the opening of the reflectors 0 and 120 is shown in FIG.
As shown in (1), if the effective display area EA of the liquid crystal light valve has a shape similar to that of the liquid crystal light valve, and the shapes of the incident surface and the exit surface of the light guide portion are substantially similar to the effective display area EA, the illumination light matching the effective display area EA. Can be easily obtained.

The present invention is not limited to the above Examples and Embodiments, but can be implemented in various modes without departing from the gist of the present invention. For example, the following modifications are possible.

(1) As described with reference to FIG.
Since the diffusing portion 252 in 0G is formed by a polished surface, a diffraction grating, a lens array, or the like, the diffusing characteristics of the diffusing portion 252 can be changed according to the intensity distribution of the incident light beam. That is, in the plane of the diffusion section 252, it is possible to change the surface roughness of the polished surface, change the grating pitch of the diffraction grating, or change the radius of curvature or the degree of eccentricity of each lens of the lens array. it can.
In this case, the intensity distribution of the substantially parallel light flux emitted from the light guide unit may be more uniform, and
There is a possibility that the length L of the light guide unit 250G may be reduced to further reduce the size of the projection display device.

In FIG. 3, the diffuser 252 is provided at one location in the light guide 250G, but may be provided at a plurality of locations. Also in this case, the intensity distribution of the incident substantially parallel light beam can be made more uniform, and the length L of the light guide portion 250G is shortened.
There is a possibility that the projection display device can be further downsized.

(2) The above-mentioned projection type display device is described by taking as an example the case where the illumination optical system of the present invention is applied to a transmission type projection type display device. However, the present invention is directed to a reflection type projection type display device. It is also possible to apply to. Here, “transmission type” means that an electro-optical device as a light modulating unit transmits light, such as a transmission type liquid crystal panel, and “reflection type” means a reflection type. This means that an electro-optical device as a light modulating unit, such as a liquid crystal panel, is of a type that reflects light. Even when the present invention is applied to a reflection type projection display device, almost the same effects as those of a transmission type projection display device can be obtained.

(3) In the above embodiment, the projection type display device for displaying a color image is described as an example. However, the illumination optical system of the present invention is applied to a projection type display device for displaying a monochrome image. It is also possible. Also in this case, the same effects as those of the projection display device can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a projection display device to which the present invention is applied.

FIG. 2 is an explanatory diagram showing the light source device 100 in an enlarged manner.

FIG. 3 shows three light guides 250R, 250G, and 25 shown in FIG.
FIG. 9B is an explanatory diagram illustrating one light guide unit 250G of FIG.

FIG. 4 is an explanatory diagram showing a cross-sectional shape of a light beam incident on the light guide unit 250G and a cross-sectional shape of a light beam emitted from the light guide unit 250G.

FIG. 5 is an explanatory view showing a first modification of the light guide section shown in FIG. 1;

6 is an explanatory diagram showing a cross-sectional shape of a light beam incident on the light guide unit 260G of FIG. 5 and a cross-sectional shape of a light beam emitted from the light guide unit 260G.

FIG. 7 is an explanatory diagram showing a second modification of the light guide section shown in FIG. 1;

8 is an explanatory diagram illustrating a cross-sectional shape of a light beam incident on the light guide unit 270G of FIG. 7 and a cross-sectional shape of a light beam emitted from the light guide unit 270G.

FIG. 9 is a perspective view showing a third modification of the light guide section shown in FIG.

FIG. 10 is an explanatory diagram illustrating an example of a light source device in a case where a cross-sectional shape of a light beam incident on a light guide unit is substantially rectangular.

11 is an explanatory diagram showing a cross-sectional shape of a light beam incident on the light guide unit 280G of FIG. 9 and a cross-sectional shape of a light beam emitted from the light guide unit 280G when the light source device 100 ′ of FIG. 10 is used. It is.

FIG. 12 is an explanatory diagram showing a first modification of the light source device shown in FIG.

FIG. 13 is an explanatory diagram showing a second modification of the light source device shown in FIG.

[Explanation of symbols]

 100, 100 ': Light source device 100ax: Axis 102: Light source lamp 102c: Center of the light source lamp 104: Elliptical reflector 104R: Reflecting surface 106: Parallelizing lens 106i: Incident surface of the parallelizing lens 106o: Exiting surface of the parallelizing lens 110 ... Light source device 110ax ... Axis 114 ... Elliptical reflector 116 ... Collimating lens 116i ... Parallizing lens incident surface 116o ... Parallizing lens emitting surface 120 ... Light source device 120ax ... Axis 124 ... Parabolic reflector 124R ... Reflecting surface 126 ... Light beam width adjusting lenses 201, 202: dichroic mirrors 203, 204, 205: reflection mirrors 250R, 250G, 250B: light guide 250Gr: reflective film 250Gi: entrance surface of the light guide 250Go: exit surface of the light guide 251a, 251b: Transparent body 252: Diffusion unit 2 60G: light guide 260Gi: entrance surface of light guide 260Go: exit surface of light guide 270G: light guide 270Gi: entrance of light guide 270Go: exit of light guide 280G: light guide 280Gi: guide Incident surface of light part 280Go ... Outgoing surface of light guide part 300R, 300G, 300B ... Liquid crystal light valve 320 ... Cross dichroic prism 321 ... Red light reflecting dichroic surface 322 ... Blue light reflecting dichroic surface 340 ... Projection lens EA ... Effective display area SC ... Screen

Claims (11)

[Claims] An illumination optical system comprising: a light source device that emits a substantially parallel light beam; and a light guide unit that makes the light intensity distribution of the light beam emitted from the light source device substantially uniform. Wherein the light guide unit comprises: a light incident surface on which light emitted from the light source device is incident; a light exit surface for emitting light incident from the light incident surface; the light incident surface and the light emission An illumination optical system, comprising: a diffusing portion provided between the light incident surface and the light exit surface; and a three-dimensional shape having the light incident surface and the light exit surface as bottom surfaces. 2. The illumination optical system according to claim 1, wherein the diffuser is a polished surface. 3. The illumination optical system according to claim 1, wherein the diffusion unit is a diffraction grating. 4. The illumination optical system according to claim 1, wherein the diffusion unit is a lens array including a plurality of lenses. 5. The illumination optical system according to claim 1, wherein a reflection film for reflecting light traveling in the light guide is formed on a side surface of the light guide. The illumination optics. 6. An illumination optical system according to claim 1, wherein the illumination light is modulated according to image information to generate a modulated light beam, and the modulated light beam is projected. A projection optical system, comprising: a light source device that radially emits light; and a rotation device that reflects and condenses the light emitted from the light source lamp. A reflector having an elliptical reflecting surface; and a collimating lens for collimating the light reflected by the reflecting surface of the reflector, wherein a cross section of the light beam emitted from the collimating lens is provided. The projection display device, wherein the shape is adjusted to a size that is included in the light incident surface of the light guide unit. 7. The projection display device according to claim 6, wherein the electro-optical device includes a substantially rectangular modulation region for performing the modulation of the illumination light, The projection display device, wherein the light exit surface has a substantially rectangular shape larger than the modulation area by a predetermined width. 8. The projection display device according to claim 6, wherein the electro-optical device includes a substantially rectangular modulation region for performing the modulation of the illumination light. The light exit surface includes the modulation region,
And has a shape substantially circumscribed to the modulation region,
Projection display device. 9. The projection display device according to claim 7, wherein the light incident surface and the light emission surface of the light guide are set to have substantially the same shape. . 10. The projection display device according to claim 7, wherein the light incident surface and the light exit surface of the light guide are larger at the light incident surface than at the light exit surface. Is set,
Projection display device. 11. The projection display device according to claim 9, wherein a cross-sectional shape of an opening of the reflector, a shape of the light incident surface of the light guide, and the light of the light guide. The projection display device, wherein the shape of the exit surface is set to be substantially similar to the modulation area.