JP2002006260A - Illumination optical system and projector using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique by which nearly one kind of polarized light is efficiently emitted in an illumination optical system. SOLUTION: This illumination optical system is equipped with a light source device 120 emitting nearly parallel bundles of rays, a polarized light generating part 130 which extends the cross sectional shape of the bundles of rays in 1st and 2nd directions orthogonal to each other while keeping the bundles of rays nearly parallel by partially separating the nearly parallel bundles of rays emitted from the light source device and which generates the bundle of rays of nearly one kind of polarized light having a specified polarization direction, a lens array 170 for dividing the bundle of rays of the nearly parallel polarized light emitted from the polarized light generating part to a plurality of bundles of rays of partially polarized light and a superposing optical system 190 for superposing the plurality of bundles of rays of partially polarized light on a specified illumination area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical system and a projector for projecting and displaying an image using the illumination optical system.

[0002]

2. Description of the Related Art In a projector, 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 to display an image. Has been realized.

FIG. 9 shows a conventional illumination optical system 9.
It is explanatory drawing which shows 00. This illumination optical system 900 includes a light source device 920 and first and second lens arrays 94.
0,950, the polarization generating optical system 960, and the superimposing lens 9
70. In FIG. 9, the illumination optical system 900
Is equivalent to a liquid crystal panel provided in the projector.

The light source device 920 includes a lamp 922 and a reflector 924 having a concave surface in the shape of a paraboloid of revolution. The light emitted from the lamp 922 is reflected by the reflector 92.
4, and a substantially parallel light beam is emitted from the reflector 924.

The first lens array 940 has a plurality of small lenses 942 arranged in a matrix. The first lens array 940 divides the substantially parallel light beam emitted from the light source device 920 into a plurality of partial light beams and emits them. The second lens array 950 also has a plurality of small lenses 952 arranged in a matrix. The second lens array 950 and the superimposing lens 970 form an image of each small lens 942 of the first lens array 940 in the illumination area LA.
It has the function of imaging on top. The partial light beam emitted from each small lens 942 of the first lens array 940 is condensed in the polarization generation optical system 960 via the second lens array 950.

The polarization generating optical system 960 includes a light shielding plate 962
, A polarizing beam splitter array 964, and a selective retardation plate 966. The light-shielding plate 962 is
2b and the opening surface 962a are arranged in a stripe pattern. The polarizing beam splitter array 964 is
Columnar glass substrate 964c having a substantially parallelogram cross section
Are bonded together. Each glass substrate 9
The polarization separation film 964a and the reflection film 964
b are alternately formed. First lens array 94
Each partial light beam emitted from 0 passes through the opening surface 962a of the light shielding plate 962 and enters the polarization splitting film 964a.
The polarization separation film 964a separates the incident partial light beam into an s-polarized light beam and a p-polarized light beam. The selective retardation plate 966 includes the opening layer 966a and the λ / 2 retardation layer 96.
6b are arranged in a stripe pattern. The aperture layer 966a transmits the incident s-polarized partial beam as it is, and the λ / 2 retardation layer 966b converts the incident p-polarized partial beam into an s-polarized partial beam having orthogonal polarization directions. . As a result, from the polarization generating optical system 960, a partial light beam having substantially one type of polarization direction (s-polarized light) is emitted.

The superimposing lens 970 includes a polarization generating optical system 96.
It has a function of superimposing a plurality of s-polarized partial light beams emitted from 0 on the illumination area LA.

As described above, in the conventional illumination optical system 900, the substantially parallel light beam emitted from the light source device 920 is divided into a plurality of partial light beams by the first lens array 940, and the divided light beams are divided. A plurality of partial light beams are converted into an s-polarized light beam by the polarization generation optical system 960. Then, the s-polarized partial light beam is superimposed on the illumination area LA by the superimposing lens 970.

[0009]

In the illumination optical system, it is preferable that the light emitted from the light source device is efficiently converted into one kind of polarized light and emitted. However, in the conventional illumination optical system 900, it is difficult to efficiently convert the light emitted from the light source device 920 into one type of polarized light and emit the same. This is because the plurality of partial light beams emitted from the first lens array 940 are condensed light, and when such condensed light is incident on the polarization splitting film 964a of the polarization beam splitter array 964, the polarization This is because it is difficult to efficiently perform polarization separation by the separation film 964a.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and has as its object to provide a technology capable of efficiently emitting almost one type of polarized light in an illumination optical system. And

[0011]

In order to solve at least a part of the above-described problems, a first apparatus of the present invention is an illumination optical system which emits a substantially parallel light beam. By separating the light source device and a part of the substantially parallel light beam emitted from the light source device, the cross-sectional shape is enlarged in the first and second directions orthogonal to each other while keeping the light beam substantially parallel, Almost 1 with a given polarization direction
A polarization generator that generates different types of polarized light beams, a lens array for dividing the substantially parallel polarized light beams emitted from the polarized light generator into a plurality of partially polarized light beams, and the plurality of partially polarized light beams. And a superimposing optical system for superimposing the bundle on a predetermined illumination area.

The polarization generating section of the illumination optical system separates a part of the substantially parallel light beam emitted from the light source device, so that the first and second directions are perpendicular to each other while the light beam is substantially parallel. And a substantially one kind of polarized light beam having a predetermined polarization direction is generated. in this way,
When a substantially parallel light beam is incident on the polarization generation unit, the light emitted from the light source device can be efficiently processed by the polarization generation unit, so that almost one type of polarized light can be efficiently processed in the illumination optical system. It becomes possible to inject well.

Further, if the magnification in the first and second directions is made substantially equal, and this illumination optical system is applied to a projector to illuminate a liquid crystal light valve, color unevenness and brightness of the projected and displayed image can be obtained. It is possible to reduce unevenness.

In the above apparatus, the polarized light generator may include:
A first beam bundle expanding unit that includes a beam splitter that separates incident substantially parallel light beams, and emits a light beam that is expanded in the first direction by using the separated light beams; A polarizing beam splitter for separating the light beam expanded in the first direction into two types of polarized light beams whose polarization directions are orthogonal to each other, and using the separated polarized light beam, the polarized light beam expanded in the second direction. And a retardation plate for aligning one polarization direction of the two types of polarized light bundles emitted from the second light bundle enlargement unit with the other polarization direction. May be provided.

Alternatively, in the above apparatus, the polarization generating section includes a polarization beam splitter that separates the incident substantially parallel light beam into two types of polarized light beams whose polarization directions are orthogonal to each other. The first using a bundle
And a beam splitter for splitting the polarized light beam expanded in the first direction, and using the separated polarized light beam. A second light beam expanding unit that emits the polarized light beam expanded in the second direction; and one of two types of polarized light beams emitted from the first or second light beam expanding unit. A phase difference plate for aligning the polarization direction with the other polarization direction.

With this configuration, the illumination optical system can expand the light beam in the first and second directions while keeping the light beam substantially parallel, and can efficiently emit substantially one type of polarized light. Becomes

In the above apparatus, the light source device may include a lamp for emitting light, a reflector having a spheroidal concave surface for reflecting the light emitted from the lamp, and a light for reflecting the light reflected by the reflector. And a collimating lens for converting the light into a parallel light.

With this configuration, the size of the substantially parallel light beam emitted from the light source device can be made relatively small, so that the polarization generating section can be downsized. As a result, the illumination optical system can be downsized. Can be realized.

In the above apparatus, the superposition optical system may be a lens array including a plurality of decentered lenses.

This makes it possible to omit the superimposed lens which is usually provided independently.

According to a second aspect of the present invention, there is provided a projector, comprising: the illumination optical system according to any one of the above; an electro-optical device for modulating light from the illumination optical system in accordance with image information; And a projection optical system that projects modulated light obtained by the electro-optical device.

Since this projector is provided with the above-mentioned illumination optical system, it is possible to efficiently emit almost one kind of polarized light in the illumination optical system. This makes it possible to improve the brightness of the image projected and displayed by the projector.

[0023]

DETAILED DESCRIPTION OF THE INVENTION First Embodiment: Next, an embodiment of the present invention will be described based on an embodiment. FIG. 1 is a schematic configuration diagram showing an example of a projector to which the present invention has been applied. The projector 1000 includes an illumination optical system 100, a color light separation optical system 200, a relay optical system 220, three liquid crystal light valves 300R, 300G, 300B, a cross dichroic prism 320, and a projection optical system.
0.

The illumination optical system 100 emits one type of linearly polarized light having a substantially uniform polarization direction. The light emitted from the illumination optical system 100 is separated into three color lights of red (R), green (G), and blue (B) in the color light separation optical system 200. Each of the separated color lights is a liquid crystal light valve 300R,
In 300G and 300B, modulation is performed according to image information. Liquid crystal light valves 300R, 300G, 300B
Includes a liquid crystal panel corresponding to the electro-optical device according to the present invention, and polarizing plates disposed on the light incident surface side and the light exit surface side. A drive unit (not shown) for supplying image information to and driving the liquid crystal panel is connected to each liquid crystal light valve. Liquid crystal light valve 300
The modulated light beam modulated in accordance with the image information in the R, 300G, and 300B is applied to the cross dichroic prism 3
20 and are projected on the screen SC by the projection optical system 340. As a result, an image is displayed on the screen SC. The configuration and function of each part of the projector as shown in FIG. 1 are described in, for example, Japanese Patent Application Laid-Open No. H10-325 disclosed by the present applicant.
No. 954, the detailed description is omitted in this specification.

The illumination optical system 100 provided in the projector 1000 can efficiently emit almost one type of polarized light, as described later. For this reason, it is possible to improve the brightness of the image projected and displayed on the screen SC.

FIG. 2 is an explanatory diagram showing the illumination optical system 100 of FIG. 1 in an enlarged manner. The illumination optical system 100 includes a light source device 120, a polarization generation optical system 130, first and second light sources.
, And a superimposing lens 190. The light beam emitted from the illumination optical system 100 is emitted with the system optical axis Lax as a central axis. In FIG. 2, the illumination area LA illuminated by the illumination optical system 100 corresponds to the liquid crystal light valves 300R, 300G, and 300B of the projector 1000 (FIG. 1).

The light source device 120 has a function of emitting substantially parallel light beams. The light source device 120 includes the lamp 12
2 and a reflector 124 having a spheroidal concave surface
And a collimating lens 126. Lamp 122
Is reflected by the reflector 124, and the reflected light is converted by the collimating lens 126 into substantially parallel light.

As the lamp 122, a metal halide lamp, a high-pressure mercury lamp, or the like can be used. In the present embodiment, an aspheric lens is used as the collimating lens 126. Specifically, an aspheric lens having a concave surface in the shape of a rotational hyperboloid on the incident surface and a flat surface on the exit surface is used. Used. For this reason, a light beam with considerably high parallelism is emitted from the light source device 120.

The polarization generating optical system 130 includes two light beam expanding units 140 and 150 and a λ / 2 retardation plate 160. The polarization generating optical system 130 has a function of expanding an incident light beam into a light beam having a size approximately four times as large and emitting the light beam. That is, the first light beam expanding unit 140 has a function of expanding the cross-sectional shape of the incident light beam almost twice in the x direction, and the second light beam expanding unit 150 Has a function of enlarging the cross-sectional shape of the same approximately twice in the y direction. Further, the polarization generating optical system 130 has a function of generating almost one kind of polarized light beam having a predetermined polarization direction from the incident light beam having no bias.

FIG. 3 is an enlarged perspective view showing the polarization generating optical system 130 of FIG. 2 in an enlarged manner. As shown in the drawing, the first and second light beam expanding units 140 and 150 are configured by combining a plurality of substantially columnar light-transmitting members having a bottom surface of a substantially right triangle. Note that, for example, glass is used as the translucent member.

The first light beam expanding section 140 includes three light transmitting members 141 to 143. The first translucent member 141 includes second and third translucent members 142 and 143.
And are joined. First and second translucent members 14
Semi-transparent mirror film (beam splitter)
The third light-transmitting member 143 has a reflective film 140b formed substantially parallel to the semi-transparent mirror film 140a. Here, the semi-transparent mirror film is a thin film that transmits a part of the incident light amount and reflects the other part, and is formed of a metal film or a dielectric multilayer film. Semi-transparent mirror film 1 of the present embodiment
40a transmits approximately 50% of the incident light amount and approximately 50%
And has an optical characteristic of reflecting light, and functions as a so-called half mirror. The reflection film 140b is a thin film that reflects most of the amount of incident light, and is formed of a dielectric multilayer film or a metal film.

The light beam incident on the first translucent member 141 is split into two light beams by the semi-transparent mirror film 140a. The light beam transmitted through the semi-transparent mirror film 140a is emitted through the second light-transmitting member 142. On the other hand, the semi-transparent mirror film 140a
The light beam reflected by the light incident on the third light transmitting member 143 is reflected by the reflection film 140b and emitted. That is, the light beam incident on the first light transmitting member 141 is separated, and the separated light beam is emitted from the second and third light transmitting members 142 and 143. Accordingly, the first light beam expanding unit 140 expands the cross-sectional shape of the incident light beam almost twice in the x direction.

The second beam expanding section 150 includes six light-transmitting members 151 to 156. The first light-transmitting member 151 includes second and third light-transmitting members 152 and 153.
And are joined. First and second translucent members 15
A polarization separation film (deflection beam splitter) 150a is formed on the interface between the first and second light-transmitting members 1 and 152.
53 includes a reflection film 15 substantially parallel to the polarization separation film 150a.
0b is formed. Here, the polarization separation film 150a
Is a thin film for separating incident non-biased light (s + p) into p-polarized light and s-polarized light, and is formed of a dielectric multilayer film. The separated p-polarized light and s-polarized light have a light amount of approximately 50% of the incident light amount.

The non-biased light beam (s + p) incident on the first translucent member 151 is separated into a p-polarized light beam and an s-polarized light beam by the polarization separation film 150a. Polarization separation film 15
0a passes through the second light-transmitting member 15
It is ejected through 2. On the other hand, the s-polarized light beam reflected by the polarization separation film 150a enters the third light transmitting member 153, is reflected by the reflection film 150b, and is emitted. That is, the unbiased light beam (s + p) incident on the first light-transmitting member 151 is separated into a p-polarized light beam and an s-polarized light beam, and the second light-transmitting member 152 and the third light beam, respectively. From the light transmitting member 153.

The fourth to sixth translucent members 154
To 156 are first to third translucent members 151 to 15
Same as 3. That is, the unbiased light beam (s + p) incident on the fourth light transmitting member 154 is separated into a p-polarized light beam and an s-polarized light beam, and the fifth light transmitting member 155 and the sixth light beam, respectively. From the light transmitting member 156. Accordingly, the second light beam expanding unit 150 expands the cross-sectional shape of the incident light beam almost twice in the y direction.

The λ / 2 phase difference plate 160 has a function as a polarization conversion element for converting incident linearly polarized light into linearly polarized light having a polarization direction orthogonal to the polarization direction. In the present embodiment, as shown in FIG.
And fifth translucent members 1 of the light beam expanding section 150 of FIG.
52, 155 are provided on the exit surface. The p-polarized light beams emitted from the second and fifth translucent members 152 and 155 are converted to s-polarized light beams by the λ / 2 retardation plate 160 and emitted. The s-polarized light beam is emitted from the third and sixth translucent members 153 and 156. As described above, the unbiased light beam (s + p) incident on the polarization generating optical system 130 is converted into an s-polarized light beam and emitted.

By disposing a λ / 2 retardation plate on the exit surfaces of the third and sixth translucent members 153 and 156 from which the s-polarized light beam is emitted, the deviation incident on the polarization generating optical system 130 can be improved. Can be converted into a p-polarized light beam and emitted.

As described above, the polarization generating optical system 130 converts the incident non-biased light beam into an s-polarized light beam, and expands the incident light beam into a nearly four-fold light beam. The light beam emitted from the polarization generation optical system 130 is
The light enters the first lens array 170 (FIG. 2).

The first lens array 170 has a plurality of small lenses 172 arranged in a matrix. Each small lens 172 is a plano-convex lens, and the external shape when viewed from the z direction is set to be similar to the illumination area LA (liquid crystal light valve). The first lens array 170 divides the substantially parallel s-polarized light beam emitted from the polarization generating optical system 130 into a plurality of s-polarized partial light beams and emits the divided s-polarized light beams.

The second lens array 180 has a plurality of small lenses 182 arranged in a matrix, and the same as the first lens array 170 is used. The second lens array 180 and the superimposing lens 190 have a function of forming an image of each small lens 172 of the first lens array 170 on the illumination area LA.

The superimposing lens 190 converts a plurality of s-polarized partial light beams having the same polarization direction into an illumination area L as shown in FIG.
It has the function of superimposing on A. At this time, the intensity distribution of the light illuminating the illumination area LA is substantially uniform.

In this embodiment, the superimposing lens 1
As 90, an aspheric lens is used. Specifically, an aspherical lens having a flat surface on the incident surface and a convex surface in the form of a hyperboloid of revolution on the exit surface is used. This can reduce the spherical aberration that can occur when the respective partial light beams split by the first lens array 170 are superimposed on the illumination area LA, so that the respective partial light beams are successfully superimposed on the illumination area LA. It becomes possible.

As can be seen from the above description, the first lens array 170 in this embodiment corresponds to the lens array of the present invention, and the superimposing lens 190 corresponds to the superimposing optical system of the present invention. Note that the second lens array 180 can be omitted.

The liquid crystal light valves 300R, 300R
The optical characteristics of 00G and 300B largely depend on the angle of the incident light (referred to as “swallow angle”). In this embodiment, the ratio of the size in the x direction to the size in the y direction of the light beam emitted from the polarization generating optical system 130 is approximately 1: 1.
It is set to be 1. Therefore, the illumination area L
The light swallow angle θx in the x and y directions of A,
θy have substantially the same magnitude. Using such an illumination optical system 100, the liquid crystal light valves 300R, 30R
By illuminating 0G and 300B, a color image without color unevenness can be projected and displayed on the screen.

As described above, the polarization generating optical system 130 in the illumination optical system 100 of the present embodiment is a semi-transparent mirror film (beam splitter) for separating incident substantially parallel light beams.
A first light beam expanding unit 140 that includes a separated light beam and emits a light beam that is expanded in the x direction using the separated light beam;
And a polarization separation film 150a for separating the light beam expanded in the x direction into two types of polarized light beams whose polarization directions are orthogonal to each other.
A second light beam enlarging unit 150 including a (polarized beam splitter) and emitting a polarized light beam expanded in the y-direction using the separated polarized light beam beam; and a second light beam expanding unit 150
Plate 160 for aligning one polarization direction of the two types of polarized light beams emitted from the light source with the other polarization direction
And In the illumination optical system 100, since the light beam incident on the polarization separation film 150a is a substantially parallel light beam, the illumination optical system 100 can efficiently emit almost one type of polarized light.

B. Second Embodiment FIG. 4 is an explanatory diagram showing an illumination optical system 400 as a second embodiment. In the illumination optical system 400, a polarization generation optical system 430 is changed from the illumination optical system 100 (FIG. 2) of the first embodiment. The other optical elements are the same as those in the first embodiment, and detailed description is omitted.

The polarization generating optical system 430 includes two light beam expanding units 440 and 450 and a λ / 2 retardation plate 460. As in the first embodiment, the polarization generation optical system 430 includes:
It has the function of expanding an incident light beam into a light beam of approximately four times the size and emitting it, and generates one kind of polarized light beam having a predetermined polarization direction from the incident light beam having no bias. It has the function to do.

FIG. 5 is an enlarged perspective view showing the polarization generating optical system 430 of FIG. 4 in an enlarged manner. First ray bundle expanding section 44
0 has three translucent members 441-443.
The first light transmitting member 441 is joined to the second and third light transmitting members 442 and 443. At the interface between the first and second translucent members 441 and 442, the polarization separation film 44 is provided.
0a is formed, and the third translucent member 443 includes
A reflection film 440b is formed substantially parallel to the polarization separation film 440a.

The unbiased light beam (s + p) incident on the first light-transmitting member 441 is separated into a p-polarized light beam and an s-polarized light beam by the polarization separating film 440a. Polarization separation film 44
0a is transmitted to the second translucent member 44.
It is ejected through 2. On the other hand, the s-polarized light beam reflected by the polarization separation film 440a enters the third light transmitting member 443, is reflected by the reflection film 440b, and is emitted. That is, the unbiased light beam (s + p) incident on the first light-transmitting member 441 is separated into a p-polarized light beam and an s-polarized light beam, and the second light-transmitting member 442 and the third light beam, respectively. From the light transmitting member 443. Thereby, the first
The beam bundle enlargement unit 440 enlarges the cross-sectional shape of the incident light beam approximately twice in the x direction.

The second light beam expanding section 450 includes six light transmitting members 451 to 456. The first translucent member 451 includes the second and third translucent members 452 and 453.
And are joined. First and second translucent members 45
A semi-transmissive mirror film 450a is formed on the interface between the first and the second light-transmitting members 452.
The reflection film 450b is formed substantially in parallel with the above.

The p-polarized light beam incident on the first translucent member 451 is split into two p-polarized light beams by the semi-transparent mirror film 450a. The p-polarized light beam transmitted through the semi-transparent mirror film 450a passes through the second light-transmitting member 452 and is emitted. On the other hand, the p-polarized light beam reflected by the semi-transparent mirror film 450a enters the third light-transmitting member 453, is reflected by the reflection film 450b, and is emitted. That is, the first translucent member 45
The p-polarized light beam incident on 1 is separated and
The polarized light beam is transmitted to the second and third translucent members 452 and 45.
Injected from 3

The fourth to sixth translucent members 454
To 456 are first to third translucent members 451 to 45
Same as 3. That is, the s-polarized light beam incident on the fourth light-transmitting member 454 is separated, and the separated s-polarized light beam is emitted from the fifth and sixth light-transmitting members 455 and 456. Thereby, the second light beam expanding unit 450
Enlarges the cross-sectional shapes of the incident p-polarized light beam and s-polarized light beam almost twice in the y direction.

In this embodiment, the λ / 2 phase difference plate 460
Are provided on the exit surfaces of the second and third translucent members 452 and 453 of the second light beam bundle expanding section 450, as shown in FIG. Second and third translucent members 452, 4
The p-polarized light beam emitted from the light beam 53
At 60, it is converted into an s-polarized partial light beam and emitted. The fifth and sixth light transmitting members 455, 45
6, an s-polarized light beam is emitted. That is, the unbiased light beam that has entered the polarization generating optical system 430 is converted into an s-polarized light beam and emitted.

By disposing a λ / 2 retardation plate on the exit surfaces of the fifth and sixth translucent members 455 and 456 from which the s-polarized light beam is emitted, if the λ / 2 phase difference plate is placed on the polarization generating optical system 430 Can be converted into a p-polarized light beam and emitted.

As described above, the polarization generating optical system 430 converts the incident non-biased light beam into an s-polarized light beam, and expands the incident light beam into a nearly four-fold light beam.

As described above, the polarization generation optical system 430 in the illumination optical system 400 of the present embodiment separates the incident substantially parallel light beam into two types of polarized light beams whose polarization directions are orthogonal to each other. Film (polarizing beam splitter)
A first light beam enlarging unit 440 that emits a polarized light beam expanded in the x direction using the separated polarized light beam, and a semi-transparent mirror film that separates the polarized light beam expanded in the x direction A beam splitter 450a including a beam splitter 450a for emitting a polarized light beam expanded in the y-direction using the separated polarized light beam; And a retardation plate 460 for aligning one polarization direction of the two types of polarized light beams with the other polarization direction. Thereby, the illumination optical system 4
00 can efficiently emit almost one type of polarized light.

C. Third Embodiment FIG. 6 is an explanatory diagram showing an illumination optical system 400 ′ as a third embodiment. The illumination optical system 400 'is almost the same as the illumination optical system 400 (FIG. 4) of the second embodiment, except that the polarization generation optical system 430' is changed. Specifically, the polarization generating optical system 430 'of the present embodiment includes two light beam expanding units 440 and 450 having the same configuration as the second embodiment, and a modified λ / 2 retardation plate 460'. Have. That is, in the present embodiment, the λ / 2 retardation plate 460 ′ is disposed between the first and second light beam expanding units 440 and 450. In addition,
Detailed description of the same optical elements as in the first and second embodiments will be omitted.

FIG. 7 is an enlarged perspective view showing the polarization generating optical system 430 'of FIG. 6 in an enlarged manner. First ray bundle enlarger 4
The unbiased light beam (s + p) incident on the first light-transmissive member 441 of FIG. 40 is separated into a p-polarized light beam and an s-polarized light beam, and the second light-transmitting member 442 and the third light beam, respectively. From the light transmitting member 443. Accordingly, the first light beam expanding unit 440 changes the cross-sectional shape of the incident light beam to x
The direction is almost doubled.

In this embodiment, the λ / 2 retardation plate 46
0 ′ is the first light beam expanding unit 440 as shown in FIG.
Of the second light transmitting member 442.
The p-polarized light beam emitted from the second translucent member 442 is converted into an s-polarized light beam by the λ / 2 retardation plate 460 ′ and emitted. The s-polarized light beam is emitted from the third translucent member 443. Thereby, in the present embodiment, the second light beam enlarging unit 45
At 0, only the s-polarized light beam is incident.

By disposing a λ / 2 retardation plate on the exit surface of the third translucent member 443 from which the s-polarized light beam is emitted, the p-polarized light beam is It is also possible to make only light incident.

The s-polarized light beam incident on the first light transmitting member 451 of the second light beam expanding portion 450 is
At a, it is split into two s-polarized light beams. Semi-transparent mirror film 450
The s-polarized light beam transmitted through the second light-transmitting member 452
It is ejected through. On the other hand, the s-polarized light beam reflected by the semi-transparent mirror film 450a enters the third light-transmitting member 453, is reflected by the reflection film 450b, and is emitted. That is, the s-polarized light beam incident on the first translucent member 451 is separated, and the separated s-polarized light beam is separated into the second and third light beams.
Are emitted from the light transmitting members 452 and 453.

The fourth to sixth translucent members 454
To 456 are first to third translucent members 451 to 45
3 and s incident on the fourth translucent member 454.
The polarized light beam is separated, and the separated s-polarized light beam is emitted from the fifth and sixth translucent members 455, 456. Accordingly, the second light beam expanding unit 450 expands the cross-sectional shape of the incident s-polarized light beam almost twice in the y direction.

As described above, the polarization generating optical system 430 'converts the incident non-biased light beam into an s-polarized light beam, and expands the incident light beam into a nearly four-fold light beam.

In the second embodiment (FIG. 5), the λ / 2 retardation plate 460 is provided on the exit surfaces of the second and third light transmitting members 452 and 453 of the second light beam expanding section 450. However, in the third embodiment (FIG. 7), the λ / 2 retardation plate 4
Reference numeral 60 ′ is provided only on the exit surface of the second light transmitting member 442 of the first light beam expanding portion 440. As in the third embodiment, the first and second light beam expanding units 440 and 45 are provided.
If the λ / 2 retardation plate 460 ′ is arranged between 0,
There is an advantage that the phase difference plate 460 'can be made relatively small.

As described above, the polarization generating optical system 430 'in the illumination optical system 400' of this embodiment separates the incident substantially parallel light beam into two types of polarized light beams whose polarization directions are orthogonal to each other. A polarization separation film (polarization beam splitter) 440a is included, and x
A first light beam enlarging unit 440 that emits a polarized light beam that has been expanded in the direction, and a semi-transparent mirror film (beam splitter) 450a that separates the polarized light beam that has been expanded in the x direction. , A second light beam expanding unit 450 that emits a polarized light beam expanded in the y direction, and one polarization direction of two types of polarized light beams emitted from the first light beam expanding unit 440. And a retardation plate 460 ′ for aligning the light with the other polarization direction. Even if you do this,
As in the second embodiment, the illumination optical system 400 ′ can efficiently emit almost one type of polarized light.

D. Fourth Embodiment FIG. 8 is an explanatory diagram showing an illumination optical system 100A as a fourth embodiment. The illumination optical system 100A is substantially the same as the illumination optical system 100 (FIG. 2) of the first embodiment, but has a second lens array 180A.
Has been changed. The second lens array 18
With the change of 0A, the superimposing lens is omitted. The other optical elements are the same as those in the first embodiment, and detailed description is omitted.

The second lens array 180A of this embodiment
Is a plurality of small lenses 182A arranged in a matrix.
have. Each small lens 182A is a decentered lens in which the center of a spherical lens is decentered, and has a system optical axis (central axis of a light beam emitted from the illumination optical system 100A) Lax
The degree of eccentricity increases as the distance from the distance increases.
Thus, the small lens 1 of the second lens array 180A
If an eccentric lens is used as 82A, the second lens array 180A will have the function of the second lens array 180 of the illumination optical system 100 shown in FIG. That is, the second lens array 180 </ b> A of the present embodiment is
It has a function of forming an image of 72 on the illumination area LA and a function as a superposition optical system.

Even if the illumination optical system 100A as in this embodiment is used, the illumination optical system 100A can efficiently emit almost one type of polarized light.

It should be noted that the present invention is not limited to the above examples and embodiments, but can be implemented in various modes without departing from the gist thereof.
For example, the following modifications are possible.

(1) In the above embodiment, the light source device 120
A lamp 122 for emitting light, a reflector 124 having a spheroidal concave surface for reflecting light emitted from the lamp 122, and a parallelizing lens 126 for parallelizing light reflected by the reflector 124. However, as the reflector, for example, a reflector having a concave surface in the shape of a paraboloid of revolution may be used. In this case, since the light reflected by the reflector becomes parallel light, the collimating lens can be omitted. However, if the light source device 120 as in the above embodiment is used, the size of the substantially parallel light beam emitted from the light source device 120 can be adjusted by adjusting the distance between the light source device 120 and the parallelizing lens 126. , Can be quite small. Thereby, the polarization generating optical systems 130, 430, 430 'can be reduced in size, and as a result, the illumination optical systems 100, 400, 400', 100
A can be reduced in size.

(2) In the above embodiment, the polarization generating optical system 1
30, 430, and 430 ′ expand the light beam in the x direction and the y direction. For example, the second light beam expanding unit 4 of the polarization generating optical system 430 ′ (FIG. 7) in the third embodiment.
By using an illumination optical system in which 50 is omitted, the light beam may be expanded only in the x direction. However,
In this case, the swallow angle θx in the x direction and the swallow angle θy in the y direction of the light incident on the illumination area LA are different, so that when the illumination optical system is applied to the projector, the projection display is performed. Color unevenness may occur in the color image. Similarly, in a projector that projects and displays a monochrome image, the displayed image may have uneven brightness. Therefore, as in the above embodiment, it is preferable that the polarization generating optical system expands the light beam in the x direction and the y direction.

As described above, the polarization generating section of the present invention generally separates a part of the substantially parallel light beams emitted from the light source device, thereby making the cross-sectional shapes orthogonal to each other while keeping the light beams substantially parallel. What is necessary is just to expand in the first and second directions and to generate almost one kind of polarized light beam having a predetermined polarization direction.

(3) In the above embodiment, the polarization generating optical system 1
Each of 30, 430, and 430 'is formed by combining a plurality of substantially columnar light-transmitting members (glass materials) on which a semi-transparent mirror film, a polarization separation film, a reflection film, and the like are formed. You may make it comprise combining the glass substrate in which the polarization separation film and the reflection film were formed. Further, instead of the glass substrate on which the reflection film is formed, a metal reflection mirror may be used. By doing so, the illumination optical systems 100, 400, 4
00 ', 100A can be reduced in weight.

(4) In the above embodiment, the case where the present invention is applied to a transmissive projector is described as an example. However, the present invention can be applied to a reflective projector. Here, “transmissive” means that the electro-optical device as light modulating means transmits light, such as a transmissive liquid crystal panel, and “reflective” means reflective liquid crystal. This means that an electro-optical device as a light modulating means, such as a panel, is of a type that reflects light. When the present invention is applied to a reflection type projector, almost the same effects as those of a transmission type projector can be obtained.

(5) In the above embodiment, the projector 10
00 has a liquid crystal panel as an electro-optical device, but may instead have a micromirror type light modulator. For example, a DMD (digital micromirror device) (trademark of TI) can be used as the micromirror light modulation device. In general, any electro-optical device may be used as long as it modulates incident light in accordance with image information.

(6) In the above embodiment, the projector 1000 for displaying a color image has been described as an example, but the same applies to a projector for displaying a monochrome image.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of a projector to which the present invention has been applied.

FIG. 2 is an explanatory diagram showing the illumination optical system 100 of FIG. 1 in an enlarged manner.

3 is an enlarged perspective view showing the polarization generating optical system 130 of FIG. 2 in an enlarged manner.

FIG. 4 is an explanatory diagram showing an illumination optical system 400 as a second embodiment.

FIG. 5 is an enlarged perspective view showing the polarization generating optical system 430 of FIG. 4 in an enlarged manner.

FIG. 6 is an explanatory diagram showing an illumination optical system 400 ′ as a third embodiment.

FIG. 7 is an enlarged perspective view showing the polarization generating optical system 430 ′ of FIG. 6 in an enlarged manner.

FIG. 8 is an explanatory diagram showing an illumination optical system 100A as a fourth embodiment.

FIG. 9 is an explanatory view showing a conventionally used illumination optical system 900.

[Explanation of symbols]

 100, 100A: Illumination optical system 1000: Projector 120: Light source device 122: Lamp 124: Reflector 126: Parallelizing lens 130: Polarization generating optical system 140: First ray bundle expanding section 140a: Semi-transparent mirror film (beam splitter) 140b ... Reflecting films 141 to 143 Translucent member 150 Second light flux expanding portion 150a Polarization separating film (polarizing beam splitter) 150b Reflecting films 151 to 156 Translucent member 160 .lambda. / 2 retardation plate 170 first lens array 180, 180A second lens array 172, 182, 182A small lens 190 superimposed lens 200 color light separation optical system 220 relay optical system 300R, 300G, 300B liquid crystal light valve 320 Cross dichroic prism 340: Projection optical system 400, 400 ... Illumination optical system 430,430 '... Polarization generating optical system 440,450 ... Beam beam expanding part 440a ... Polarization separation film (polarization beam splitter) 440b ... Reflection film 441-443 ... Transmissive member 450a ... Semi-transparent mirror film (beam) Splitter) 450b Reflective films 451 to 456 Translucent members 460, 460 '.lambda. / 2 retardation plate 900 Illumination optical system 920 Light source device 922 Lamp 924 Reflector 940, 950 Lens array 942, 952 Small lens 960 ... Polarization generating optical system 962 ... Light shielding plate 962a ... Opening surface 962b ... Light shielding surface 964 ... Polarization beam splitter array 964a ... Polarization separation film 964b ... Reflection film 964c ... Glass substrate 966 ... Selection phase difference plate 966a ... Opening layer 966b .... lambda./2 phase difference layer 970 ... superimposed lens Lax ... system optical axis L ... illumination region SC ... screen

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 19/00 G02B 19/00 2H099 G02F 1/13 505 G02F 1/13 505 5C058 1/13357 G03B 21/00 E 5C060 G03B 21/00 21/14 A 21/14 H04N 5/74 A H04N 5/74 9/31 C 9/31 G02F 1/1335 530 F term (reference) 2H042 CA07 CA10 CA14 CA17 DD07 DE04 2H049 BA06 BB62 BC22 2H052 BA02 BA03 BA09 BA14 2H088 EA15 HA13 HA15 HA20 HA24 HA25 MA06 2H091 FA05X FA05Z FA10Z FA11Z FA14Z FA17Z FA26X FA26Z FA29Z LA03 MA07 2H099 AA12 BA09 CA02 CA08 DA05 5C058 AA06 BA05 EA02 BA14 EA02 EA02 EA02 HD00 HD02 JA19 JA20

Claims (6)

[Claims] 1. An illumination optical system, comprising: a light source device that emits a substantially parallel light beam; and a part of the substantially parallel light beam that is emitted from the light source device, the light beam device outputs a substantially parallel light beam. A polarization generator that expands the cross-sectional shape in the first and second directions orthogonal to each other and generates substantially one type of polarized light beam having a predetermined polarization direction; The parallel polarized light beam
An illumination optical system, comprising: a lens array for splitting a plurality of partially polarized light beams; and a superimposing optical system for superimposing the plurality of partially polarized light beams on a predetermined illumination area. 2. The illumination optical system according to claim 1, wherein the polarization generator includes a beam splitter that separates incident substantially parallel light beams, and uses the separated light beams to generate the first light. A first light beam expanding unit that emits the light beam expanded in the first direction; and a polarization beam splitter that separates the light beam expanded in the first direction into two types of polarized light beams whose polarization directions are orthogonal to each other. Using the separated and bundled polarized light beams
A second light beam expanding unit that emits the polarized light beam expanded in the direction of the above, and one of the two types of polarized light beams emitted from the second light beam expanding unit is changed to the other polarization direction. An illumination optical system comprising: a retardation plate for aligning the directions. 3. The illumination optical system according to claim 1, wherein the polarization generation unit converts the incident substantially parallel light beams into light beams whose polarization directions are orthogonal to each other.
A first beam bundle expander that includes a polarizing beam splitter that separates polarized light beams into different types, and that emits a polarized light beam that is expanded in the first direction using the separated polarized light beams; A beam splitter that separates the polarized light beam expanded in the direction of the second light beam expanding section that emits the polarized light beam expanded in the second direction using the separated polarized light beam, An illumination optical system, comprising: a retardation plate for aligning one polarization direction of the two types of polarized light beams emitted from the first or second light beam expanding unit with the other polarized light direction. 4. The illumination optical system according to claim 1, wherein the light source device comprises: a lamp for emitting light; and a spheroidal surface for reflecting light emitted from the lamp. An illumination optical system, comprising: a reflector having a concave surface; and a collimating lens for collimating light reflected by the reflector. 5. The illumination optical system according to claim 1, wherein the superposition optical system is a lens array including a plurality of decentered lenses. 6. A projector, the illumination optical system according to claim 1, an electro-optical device that modulates light from the illumination optical system according to image information, and the electro-optical device. And a projection optical system for projecting the modulated light obtained in (1).