JP2002072139A - Illumination optical system and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination optical system that can correspond to the high wattage of a light source and be miniaturized. SOLUTION: This illumination optical system 10 is provided with a lens array 12, which divides a luminous flux emitted from a light source 111 into parted luminous fluxes, and a polarization-converting element 15, which divides each of the parted luminous fluxes into two kinds of polarized luminous fluxes and then converts them to one kind of polarized luminous flux having a uniform polarization direction. In this case, the polarization-converting element 15 comprises polarization-converting parts 151 which are placed in the direction X of the separation of the polarization luminous flux, and a size W2 in the direction X of the separation of a polarization-converting part 152 in the second row is larger than a size W1 in the direction of the separation of other polarization-converting parts 151. As the size of light source image in the direction X of the separation by the parted luminous flux in the second row becomes large in a light source having a long arc length with increased wattage, a use rate of light of the light source is improved and the size of the polarization- converting element 15 does not become larger than necessary only by making the polarization-converting part 152, which corresponds to this, large in size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a light source and a plurality of small lenses arranged in a matrix in a plane perpendicular to the optical axis of a light beam emitted from the light source. A lens array that divides the light into light beams and forms a plurality of light source images in a plane perpendicular to the optical axis;
The present invention relates to an illumination optical system including a polarization conversion element that separates polarized light into different types of polarized light and then converts the polarized light into one type of polarized light having a uniform polarization direction, and a projector including the illumination optical system.

[0002]

2. Description of the Related Art Conventionally, a light source, an electro-optical device such as a liquid crystal panel for modulating a light beam emitted from the light source in accordance with image information, and a projection optical device for enlarging and projecting the light beam modulated by the electro-optical device. A projector having a system is used. Such a projector employs an illumination optical system including a light beam splitting optical element and a polarization conversion element on the optical path from the light source to the electro-optical device, thereby using the light from the light source without waste, and improving brightness and color unevenness. The device has been devised so that a projection image without defects can be formed.

A light beam splitting optical element splits a light beam emitted from a light source into a plurality of partial light beams and forms a plurality of light source images in a plane perpendicular to the optical axis. For example, a lens array configured by arranging a plurality of small lenses in a matrix in a plane orthogonal to the optical axis of a light beam emitted from a light source is employed. By employing such a lens array, a light beam emitted from a light source such as a high-pressure mercury lamp or a metal halide lamp is divided into a plurality of partial light beams. It is possible to irradiate an illumination light beam with a uniform distribution.

Further, the polarization conversion element separates an incident light beam having a random polarization direction into two types of polarized light beams, and rotates one of the polarized light beams to emit a light beam having the same polarization direction. Optical element. Specifically, the polarization conversion element includes a plurality of polarization conversion units corresponding to a plurality of light source images formed by the lens array, and the polarization conversion unit is one of two types of polarized light beams having different polarization directions. And a reflection film that reflects the other polarized light beam that reflects the other polarized light beam, and a phase difference plate that rotates the polarization direction of one of the two types of polarized light beams. You. By adopting such a polarization conversion element, the polarization direction of the light beam emitted from the light source can be aligned in one direction, so that the amount of polarized light beam blocked by the polarizing plate disposed in the optical path to the liquid crystal panel is reduced. Thus, there is an effect that the utilization rate of the light source light can be improved.

Conventionally, when designing an illumination optical system including the above-described light source, lens array, and polarization conversion element, the arc length of the light source is shortened to reduce the size of a plurality of light source images formed by the lens array. By arranging a polarization conversion unit having a uniform width in the direction of separating the polarized light beam according to the plurality of light source images to be formed, the polarization conversion element is downsized, and the projector including the illumination optical system is downsized.

[0006]

In such a projector, the wattage of a light source has been promoted in recent years in order to increase the brightness of a projected image. However, such a light source has a long life. In order to ensure high luminance, a lamp having a long arc length has been adopted.
However, when such a light source having a long arc length is used, a plurality of light source images formed by the lens array become large, and the width dimension of the polarization conversion unit arranged in accordance therewith becomes large. There is a problem that it is difficult to reduce the size of the illumination optical system and downsize the projector.

An object of the present invention is to provide an illumination optical system and a projector which can cope with a high wattage light source and can be downsized.

[0008]

To achieve the above object, an illumination optical system according to the present invention comprises a light source and a plurality of small light sources arranged in a matrix in a plane perpendicular to the optical axis of a light beam emitted from the light source. A lens array configured by arranging lenses, dividing the light beam into a plurality of light beams, and forming a plurality of light source images in a matrix in a plane perpendicular to the optical axis; And a polarization conversion element that converts the polarized light into one kind of polarized light having a uniform polarization direction after the light is separated into light fluxes. , And each polarization conversion unit is characterized in that the dimension in the separation direction is set based on the dimension in the same direction of each light source image.

In the present invention, when observing a plurality of light source images formed by the above-described lens array, the plurality of light source images become smaller and have lower brightness as the distance from the center of the optical path increases. Specifically, among a plurality of light source images formed in a matrix in the orthogonal plane, the light source image in the first column has the highest luminance in the direction of separation of the polarization conversion element from the center of the optical path, and then has the second column. The brightness of the eyes is high, and the width in the separation direction is the largest. The light source images in the third column have lower luminance and a smaller width in the separation direction than the light source images in the first and second columns. , The brightness is low and the width dimension is getting smaller.

Further, as described above, the polarization conversion section transmits the polarized light separating film that transmits one of the two types of polarized light beams having different polarization directions and reflects the other, and reflects the other separated polarized light beam. And a retardation plate that rotates one of the polarization directions of the two types of polarized light beams. According to the present invention, by setting the size of the polarization conversion unit in the separation direction according to the size of the plurality of light source images in the separation direction, the minimum necessary for separating and converting each light source image is obtained. Since the size of the polarization conversion unit can be configured, the polarization conversion element does not become unnecessarily large.
Therefore, even if the arc length of the light source is increased due to the high wattage of the light source, the polarization conversion unit can be configured with a size required for each light source image, and the polarization conversion element can be reduced in size, and the illumination optical system and the optical system can be reduced. , The size of the projector including the projector can be reduced.

Another illumination optical system according to the present invention comprises a light source and a plurality of small lenses arranged in a matrix in a plane perpendicular to the optical axis of a light beam emitted from the light source.
A lens array that divides the light beam into a plurality of partial light beams and forms a plurality of light source images in a matrix in a plane perpendicular to the optical axis, and separates each partial light beam into two types of polarized light beams; A polarization conversion element configured to convert the polarized light into one kind of polarized light having a uniform direction, wherein the polarization conversion element includes a plurality of polarization conversion units arranged in a direction in which the polarized light is separated. Among the plurality of polarization conversion units,
The polarization conversion units in the second column corresponding to the light source images arranged in the second column in the separation direction around the optical axis have dimensions in the separation direction larger than dimensions in the same direction of other polarization conversion units. Is also large.

That is, when observing the light source images formed in a matrix in a plane perpendicular to the optical axis by the lens array, the light source images of the second row arranged in the separation direction with the optical axis as the center are separated. The light source image has the largest size and high brightness. Therefore, it is possible to improve the utilization rate of the light source light by configuring the polarization conversion unit in the second column to include the light source image in the second column and making the other polarization conversion units smaller than this. Since it is not necessary to increase the size of the other polarization conversion units more than necessary, the size of the polarization conversion element can be reduced, and the above object can be achieved.

In the above description, the dimension of the other polarization conversion section in the separation direction is the first dimension arranged in the separation direction with the optical axis as the center.
It is preferable to be defined by the dimension in the same direction of the polarization converter corresponding to the light source image in the row. As described above, the light source images in the first column are the light source images closest to the optical axis and have high luminance, and the light source images in the third and fourth columns are lighter than the light source images in the first column. The luminance is low and the dimension in the separation direction is small. Therefore,
If the polarization conversion units in the third and fourth columns are configured in the separation direction dimensions of the polarization conversion unit corresponding to the light source image in the first column, the third
The light source images in the fourth and fourth rows can be reliably introduced into the polarization separation film. By defining the size of the other polarization converter in the separation direction in this way, the polarization converter can be configured with only two types of polarization converters, thereby simplifying the manufacture of the polarization converter.

In the case where the second lens array is disposed between the above-mentioned lens array and the polarization conversion element, the principal ray of each small lens constituting the lens array is transmitted to the polarization conversion element in parallel with the optical axis. Preferably, the small lenses making up the second lens array are decentered so that they are incident. Here, the second lens array is provided to make the principal ray of each partial light beam split by the lens array incident on the polarization conversion element in parallel with the optical axis. It is preferable to use a decentered lens which is decentered so that a principal ray is incident on the polarization conversion element in parallel with the optical axis. Further, “set according to the arrangement of the polarization conversion unit” means, for example, that the boundary between the small lenses of the second lens array corresponds to the position of the reflection mirror constituting the polarization conversion unit. You just need to design the array. Since such a second lens array is provided, the principal ray of each partial light beam can be made incident on the polarization splitting film of the polarization conversion section in parallel with the optical axis. A point on the optical axis, for example, a light beam emitted from the illumination optical system can cross over an image forming area of an electro-optical device that modulates according to image information.

Further, when the above-mentioned polarization conversion section has a polarization separation film for separating two kinds of polarized light beams,
It is preferable that the small lenses constituting the lens array as the light beam splitting optical element are decentered so that a light source image by each partial light beam is formed near the polarization separation film. By decentering the small lenses of the lens array in this way,
The separation efficiency of the polarization separation film is improved, and the utilization rate of light from the light source can be further improved.

The present invention can also be configured as a projector including the above-described illumination optical system and an electro-optical device that modulates a light beam emitted from the illumination optical system according to image information. The same operation and effect can be obtained, and a projector with high luminance and small size can be obtained.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram illustrating a structure of a projector 1 according to an embodiment of the present invention.
In the following description, the Z-axis direction is the direction at which the light beam travels, and the Y-axis direction is the direction at 12:00 toward the traveling direction of the light beam (see FIG. 1).
, The X-axis direction indicates the direction of 3 o'clock toward the traveling direction of the light beam. This projector 1
Illumination optical system 10, color separation optical system 30, relay optical system 5
0, an electro-optical device 70, a cross dichroic prism 80 as a color combining optical system, and a projection lens 90 as a projection optical system.

In the projector 1, a light beam emitted from the illumination optical system 10 is separated into red light R, green light G, and blue light B by a color separation optical system 30, and only the blue light B is transmitted via a relay optical system 50. After being introduced into the electro-optical device 70, the electro-optical device 70 modulates each of the color lights R, G, and B in accordance with image information, and synthesizes the modulated color lights R, G, and B with the cross dichroic prism 80. The projection image is configured to be enlarged and projected on the screen 100 via the projection optical system 90.

The illumination optical system 10 includes a light source device 11, a first lens array 12, a reflection mirror 13, a second lens array 14, a PBS array 15 serving as a polarization conversion element, and a superposition lens 16. The light source device 11 includes a light source 111 and a reflector 112. Light source 11
In the case of 1, a metal halide lamp having an arc length of 2 mm or more is adopted in order to cope with a high wattage, and a high luminance and a long life are achieved. Reflector 11
2 is a parabolic reflector, and the light source 111
Are arranged at the focal position of the reflector 112. The diffused light emitted from the light source 111 has its emission direction aligned in the Z-axis direction by the reflector 112,
It becomes a light beam collimated in the axial direction.

The first lens array 12 is a light beam splitting optical element that splits the light beam emitted from the light source device 11 into a plurality of partial light beams, and is arranged in a matrix in a plane orthogonal to the Z axis which is the optical axis. And a plurality of small lenses 121. These plurality of small lenses 121 are provided by P
The light source image by each partial light beam is decentered by the polarization separation film 151 </ b> B of the BS array 15, and the amount of decentering increases toward the peripheral portion of the first lens array 12. Each of the small lenses 121 is set to have the same aspect ratio as the image forming areas of the liquid crystal panels 71R, 71G, and 71B described later. The reflection mirror 13
This is an optical element that bends the emission direction of each partial light beam divided by the first lens array 12 by 90 °. As shown in FIG. 1, the optical path from the light source 111 to the projection optical system 90 has a U-shape. The projector 1 is provided to reduce the planar shape of the projector 1 as much as possible.

The second lens array 14 is an optical element that causes the principal ray of each partial light beam split by the first lens array 12 to be incident perpendicularly to the light incident end face of the PBS array 15, that is, in parallel with the optical axis. Yes, the first lens array 12
In the same manner as described above, a plurality of small lenses 141 are arranged in a matrix in a plane perpendicular to the Z axis. And
Each of the small lenses 141 is provided so that the principal ray of each partial light beam enters the PBS array 15 in parallel with the optical axis.
1 are eccentric according to the arrangement. It should be noted that the second lens array 14 transmits the principal ray of each partial light beam to the PBS array 15.
Since it is only necessary to have a function of making the light incident parallel to the optical axis, like the small lens 121 of the first lens array 12,
The size of each small lens 141 is adjusted by the size of the liquid crystal panels 71R and 71.
It is necessary to match the aspect ratio of the image forming area of G, 71B,
Not necessarily.

The PBS array 15 includes the first lens array 1
An optical element that divides each partial light beam divided by 2 and enters through the second lens array 14 into two types of polarized light beams having different polarization directions, and then converts the divided light beams into one type of polarized light beam having the same polarization direction. As shown in FIG. 2, a plurality of polarization conversion units 1 symmetrically arranged about the Z axis serving as the optical axis.
51, 152, each of the polarization converters 151, 152
Are arranged along the direction of separation of polarized light beams, that is, along the X-axis direction. As illustrated in FIG. 3, the polarization conversion unit 151 includes a plurality of translucent members 151 </ b> A stacked in the X-axis direction that is a direction in which the polarized light beam is separated, and an adjacent translucent member 151.
A interposed and alternately arranged polarization separation films 151
B and the reflection film 151C, a light-shielding plate 151D is provided on the light-incident side end surface of the polarization conversion unit 151, and a phase difference plate 151E is provided on the light-irradiation side end surface.

The polarization separation film 151B has a function of spatially separating an incident non-polarized light beam into two types of linearly polarized light beams whose polarization directions are substantially orthogonal. That is, the polarization separation film 1
The light beam incident on the polarization separation film 151B is a first linearly polarized light beam that is transmitted light transmitted through the polarization separation film 151B.
1B, and is separated into a second linearly polarized light beam, which is reflected light whose traveling direction is bent by approximately 90 °. In the present embodiment, the first linearly polarized light beam is a P-polarized light beam, and the second linearly polarized light beam is an S-polarized light beam.
Are formed to have a characteristic and an angle so as to reflect the reflected light substantially parallel to the X-axis direction. Specifically, the polarization separation film 15
1B is approximately 45 ° with respect to a surface on which a plurality of light source images are formed.
It is inclined to become. This polarization separation film 151B
Can be realized by a dielectric multilayer film.

The reflecting film 151C has a function of reflecting the reflected light from the polarized light separating film 151B again and directing the traveling direction to the substantially same direction as the traveling direction of the transmitted light. This reflection film 1
The function of 51C can be realized by a dielectric multilayer film, an aluminum film, or the like formed on the translucent member 151A, and is disposed substantially parallel to the polarization separation film 151B. Light shield plate 151
D is a reflection film 1 on the light-incident end face of the translucent member 151A.
It is provided according to the arrangement of 51C, and blocks partial light beams from entering the light beam incident end face. When a partial light beam is incident on this portion, it becomes a polarization state opposite to the normal polarization state, resulting in wasted light. And
This wasted light is transmitted to the PBS array 15 and the liquid crystal panel 71.
R, 71G, and 71B contribute to the temperature rise,
In order to prevent this, a light shielding plate 151D is provided.

The phase difference plate 151E has a function of making the polarization direction of one of the transmitted light and the reflected light substantially coincide with the polarization direction of the other polarized light beam. Are provided in accordance with the arrangement of the polarization separation film 151B, and convert the polarization direction of a light beam transmitted through the polarization separation film 151B. In the present embodiment, a half-wave plate is used as the retardation plate 151E, and the polarization direction of the light beam transmitted through the polarization separation film 151B is rotated by about 90 °, and as a result, the light is reflected by the polarization separation film 151B and further reflected. The light beam reflected by the film 151C has the same polarization direction as the light beam, and one type of polarized light beam, that is, all of the light beams are emitted as S-polarized light beams.

The type of retardation plate and its position are not limited as long as the polarization directions of the two polarized light beams separated by the polarization separating film 151B can be unified into one type of polarized light beam. For example, two types of retardation plates having different phase differences are arranged on the emission-side end face from which the transmitted light of the polarization separation film 151B is emitted and the emission-side end face from which the reflected light is emitted, respectively, and pass through each phase difference plate. It is also possible to adopt a configuration in which the polarization directions of the polarized light beams are adjusted. Such a polarization converter 151 includes a light-transmitting plate-like member having a polarization separation film 151B formed on the surface and a reflective film 151C formed on the back surface by vapor deposition or the like, and a plate-like member having no film formed thereon. Can be manufactured by laminating and bonding, and then cutting at an angle of 45 ° in the thickness direction.

The polarization converter 152 also has the same structure as the polarization converter 151, but has a different width dimension along the X-axis direction, and accordingly, a different depth dimension along the Z-axis direction than the polarization converter 151. I do. Width dimension of the polarization conversion section 152,
The depth dimension is set based on the size of a plurality of light source images divided and formed by the first lens array 12. That is,
As shown in FIG. 4, the light beam emitted from the light source device 11 is divided into a plurality of partial light beams by the first lens array 12, and the light source image S in the first column in the X-axis direction with the optical axis O as a base point.
First, a light source image S2 in the second column and a light source image S3 in the third column are formed. The width dimension W2 of the polarization conversion unit 152 is set to approximately twice the dimension L2 of the light source image S2 because the light source image S2 in the second column is separated into two polarized light beams by the polarization separation film 151B. Is done. On the other hand, the light source image S in the first column
The width dimension W1 of the polarization conversion unit 151 that performs polarization conversion of the light source images S3 in the first and third columns is substantially twice as large as the dimension L1 of the light source images S1 so as to include the light source images S1 in the first column. Is set to The reason why the width W2 of the polarization conversion unit 152 in the second column is increased in this way is that the partial light beams split by the first lens array 12 spread radially from the optical axis O, as shown in FIG. This is because there is a characteristic of forming a light source image. That is, since the light source image S1 in the first column has a strong tendency to spread in the Y-axis direction, the width dimension L1 in the X-axis direction of the light source image S1 does not increase. On the other hand, the light source image S2 in the second column has a strong tendency to spread in the X-axis direction, so that the width dimension L2 increases accordingly.

As shown in FIG. 2, the superimposing lens 16
This is an optical element for superimposing the respective partial luminous fluxes polarized by the BS array 15 on the image forming areas of the liquid crystal panels 71R, 71G, and 71B described later.
Position of the light source image by the liquid crystal panels 71R, 71G
Of the image forming area. The positional relationship between the first lens array 12 and the PBS array 15 described above is as follows.
When viewed from the Z-axis direction, the chief ray of the small lens 121 constituting the first lens array 12 has a positional relationship such that it passes through substantially the center of the polarization separation film 151B of the PBS array 15, and the separation dimension is small. The dimensions are such that the position of the light source image formed by the lens 121 is substantially at the center of the polarization separation film 151B. On the other hand, the positional relationship between the second lens array 14 and the PBS array 15 is such that the boundary between the small lenses 141 constituting the second lens array 14 overlaps substantially the center of the reflective film 151C of the PBS array 15. It has been.

The design of the illumination optical system 10 is performed in the following procedure. (1) First, the size and the number of divisions of the first lens array 12 are determined. (2) First lens array 12 and second lens array 14
The focal length of the intermediate and superimposing lens 16 is determined.

(3) The pitch of the polarization converters 151 and 152 of the PBS array 15 is determined based on the size of the arc image of the light source 111. (4) Each small lens 121 of the first lens array 12 is decentered based on the pitch of the polarization conversion units 151 and 152 of the PBS array 15 so that the conversion efficiency of the PBS array 15 is improved. (5) Finally, the size of the second lens array 14 is determined, and the small lenses 141 of the second lens array 14 are decentered so that the emission light of each principal ray is parallel to the optical axis.

The color separation optical system 30 includes two dichroic mirrors 31 and 32 and a reflection mirror 33,
The illumination optical system 10 is
A plurality of partial luminous fluxes emitted from red light R, green light G,
It has a function of separating the light into three color lights of blue light B. The dichroic mirror 31 has a function of separating only the red light R of the light flux emitted from the illumination optical system 10 and transmitting the other green light G and blue light B. The dichroic mirror 32 has a function of reflecting the green light G and transmitting the blue light B among the green light G and the blue light B transmitted through the dichroic mirror 31. The relay optical system 50 includes an incident side lens 51, a relay lens 5
3 and reflection mirrors 55 and 57, and has a function of guiding color light, for example, blue light B, separated by the color separation optical system 30 to the liquid crystal panel 71B. As can be seen from FIG. 1, the incident side lens 51 and the relay lens 53 are provided because the optical path of the blue light B is longer than the optical paths of the red light R and the green light G. The image forming position of the luminous flux by the combined lens of the side lens 51 and the relay lens 53 is defined as an image forming area of the liquid crystal panel 71B.

The electro-optical device 70 includes liquid crystal panels 71R, 71G, and 71B serving as three electro-optical devices.
These use, for example, a polysilicon TFT as a switching element, and each color light separated by the color separation optical system 30 is supplied to the three liquid crystal panels 71R and 71R.
G and 71B modulate according to image information to form an optical image. The cross dichroic prism 80 serving as the color synthesizing optical system includes three liquid crystal panels 71R and 71R.
A color image is formed by synthesizing an image modulated for each color light R, G, B emitted from G, 71B. In the cross dichroic prism 80, a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in an approximately X shape along the interface of the four right-angle prisms. The three color lights R, G, and B are combined by the dielectric multilayer film. The projection lens 90 is for projecting a projection image on the screen 100 in an enlarged manner, and is configured as a unit in which a group lens including a plurality of lenses is incorporated in a metal housing.

Next, the operation of the projector 1 having the above-described structure will be described. (1) The light beam emitted from the light source 111 is reflected by the reflector 11
2, the light is emitted in the Z-axis direction. (2) After being divided into a plurality of partial light beams by the first lens array 12 and bending the traveling direction by 90 ° by the reflection mirror 13, the direction of each partial light beam is adjusted by the second lens array 14, and the PBS array 15 is incident.

(3) The luminous flux adjusted to S-polarized light by the PBS array 15 is condensed by the superimposing lens 16 and separated by the color separation optical system 30 into red light R, green light G, and blue light B. (4) Each of the color lights R, G, and B is a liquid crystal panel 71R, 71G,
An image is formed on the image forming area 71B, and the liquid crystal panel 71R,
After the modulation according to the image information is performed by 71G and 71B, each color light R,
Images for each of G and B are combined. The synthesized image is enlarged and projected on the screen 100 by the projection lens 90.

According to the present embodiment, the following effects can be obtained. Since the width W2 of the polarization conversion unit 152 is set to include the light source image S2 in the second column and the width W1 of the other polarization conversion units 151 is set smaller than this, the light from the light source 111 is set. And the size of the PBS array 15 does not become unnecessarily large. Further, a polarization conversion unit 151 that performs polarization conversion of the light source image S1 in the first column and the light source image S3 in the third column.
Is defined based on the light source image S1 in the first column, so that the PBS array 15 is divided into two types of polarization conversion units 151, 1
52, the manufacturing is simplified, and the utilization rate of the light source light is further increased by using all the partial light beams forming the light source image S1 in the first row having the highest luminance.

Further, the second lens array 14 and the PB
Since the positional relationship of the S array 15 is set such that the boundary between the small lenses 141 and the reflective film 151C correspond to each other, each principal ray is parallel to the optical axis with respect to the polarization conversion units 151 and 152. Can be incident. Therefore, even if the optical path length of the polarized light beam transmitted through the polarization separation film 151B is different from the optical path length of the reflected polarized light beam, the principal rays of each polarized light beam can be overlapped by crossing the optical axis at the same position at the same position. . Since the small lenses 121 constituting the first lens array 12 are decentered so as to converge each partial light beam at the center of the polarization separation film 151B of the PBS array 15, the separation efficiency in the polarization separation film 151B is reduced. Improve,
The light utilization rate of the light source 111 can be further improved.

The present invention is not limited to the above embodiment, but includes the following modifications. In the above embodiment, the PBS array 15 is constituted by the two types of polarization conversion units 151 and 152, but the present invention is not limited to this. That is, the light source image S shown in FIG.
The PBS array may be configured by arranging three types of polarization conversion units corresponding to the sizes of 1 to S3 in the direction of separating the polarized light beam. Thereby, the size of the polarization conversion unit that separates the light source image S3 can be further reduced, which is more preferable for downsizing the illumination optical system.

In the above embodiment, the first lens array 12 is configured to split the light beam emitted from the light source into partial light beams as shown in FIG.
Although the size and number of the polarization conversion units 151 and 152 in the BS array 15 are set, the number of divisions of the partial light beam can be appropriately set according to the size of the electro-optical device, the size of the light source, and the like. Then, the size and the number of the polarization conversion units constituting the polarization conversion element may be set. Further, in the above embodiment, the liquid crystal panels 71R, 71R as the electro-optical device 70.
G and 71B have been adopted, but are not limited to this. That is, the present invention may be applied to a projector using an electro-optical device other than a liquid crystal device, such as a device using a micromirror. The present invention may be applied to a projector.

In the above embodiment, the projector 1
Are separated into three color lights R, G, and B by the color separation optical system 30, and the liquid crystal panels 71R, 71G,
Although the projector is a three-panel projector that performs light modulation at 71B, the present invention is not limited thereto, and the present invention may be applied to a two-panel projector or a single-panel projector. In addition, specific structures, shapes, and the like at the time of carrying out the present invention may be other structures and the like as long as the object of the present invention can be achieved.

[0040]

As described above, according to the present invention, the size of the polarization conversion section in the separation direction is set in accordance with the size of the light source image, so that the polarization conversion section can be formed with a minimum necessary size. Since the polarization conversion element can be configured, the polarization conversion element does not become unnecessarily large, and can correspond to a light source having a long arc length with a high wattage, and can be downsized. can do.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a structure of a projector according to an embodiment of the invention.

FIG. 2 is a schematic diagram illustrating a positional relationship between a lens array and a polarization conversion element in the embodiment.

FIG. 3 is a sectional view illustrating a structure of a polarization conversion element in the embodiment.

FIG. 4 is a front view showing a plurality of light source images divided and formed by a lens array in the embodiment.

[Explanation of symbols]

 Reference Signs List 1 projector 10 illumination optical system 12 first lens array (lens array) 14 second lens array 15 PBS array (polarization conversion element) 111 light source 121 small lens 141 small lens 151, 152 polarization conversion unit 151B polarization separation film W1, W2 separation Direction dimensions S1, S2, S3 Light source image

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/13357 G03B 21/00 E 5C058 G03B 21/00 21/14 A 21/14 H04N 5/74 A H04N 5/74 G02F 1/1335 530 F-term (reference) 2H049 BA05 BA43 BB01 BC01 BC22 2H052 BA02 BA03 BA09 BA14 2H088 EA15 EA18 HA12 HA13 HA14 HA15 HA18 HA20 HA21 HA24 HA26 HA28 MA20 2H091 FA05Z FA10Z FA11Z FA21Z FAZZ FA14Z LA11 LA15 MA07 2H099 AA12 BA09 CA02 CA08 DA05 5C058 AA06 BA05 BA06 EA12 EA13 EA14 EA26 EA51

Claims (7)

[Claims] 1. A light source, comprising a plurality of small lenses arranged in a matrix in a plane orthogonal to the optical axis of a light beam emitted from the light source, dividing the light beam into a plurality of partial light beams, A lens array that forms a plurality of light source images in a matrix in a plane perpendicular to the optical axis, and separates each partial light beam into two types of polarized light beams, and then converts them into one type of polarized light beam having a uniform polarization direction. An illumination optical system comprising: a polarization conversion element, wherein the polarization conversion element is configured by a plurality of polarization conversion sections arranged in a direction in which the polarized light flux is separated, and each polarization conversion section has a dimension in the separation direction. Are set based on the size of each light source image in the same direction. 2. A light source, comprising a plurality of small lenses arranged in a matrix in a plane orthogonal to an optical axis of a light beam emitted from the light source, dividing the light beam into a plurality of partial light beams, A lens array that forms a plurality of light source images in a matrix in a plane perpendicular to the optical axis, and separates each partial light beam into two types of polarized light beams, and then converts them into one type of polarized light beam having a uniform polarization direction. An illumination optical system comprising: a polarization conversion element, wherein the polarization conversion element includes a plurality of polarization conversion units arranged in a direction in which the polarized light flux is separated; The polarization conversion units in the second column corresponding to the light source images arranged in the second column in the separation direction around the axis have a dimension in the separation direction larger than that in the same direction of the other polarization conversion units. An illumination optical system, comprising: 3. The illumination optical system according to claim 2, wherein the dimension of the other polarization conversion section in the separation direction is a first row of light source images arranged in the separation direction about the optical axis. An illumination optical system characterized by being defined by the same dimension of the polarization conversion section corresponding to the above. 4. The illumination optical system according to claim 1, wherein a second lens array is disposed between said lens array and said polarization conversion element. The illumination optical system is characterized in that the arrangement of the constituent small lenses is set in accordance with the arrangement of the polarization converters constituting the polarization conversion element. 5. The illumination optical system according to claim 4, wherein the principal ray of each of the small lenses constituting the lens array is incident on the polarization conversion element in parallel with an optical axis. An illumination optical system characterized in that the small lens constituting (1) is decentered. 6. The illumination optical system according to claim 1, wherein the polarization conversion unit has a polarization separation film for separating two types of polarized light beams, and An illumination optical system characterized in that the small lens is decentered so that a light source image is formed by each partial light beam in the vicinity of the polarization separation film. 7. An illumination optical system according to claim 1, further comprising an electro-optical device for modulating a light beam emitted from the illumination optical system in accordance with image information. A projector characterized by the above-mentioned.