JP2001042430A - Illumination optical system and projection display device using the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the light use efficiency of an illumination optical system. Further, a lens array used for the split optical system is easily manufactured. An illumination optical system according to the present invention includes a light source, a split optical system, and a superposition optical system. The splitting optical system includes a first lens array having a plurality of small lenses for splitting light emitted from the light source into a plurality of partial light beams, and a plurality of small lenses respectively corresponding to the plurality of small lenses of the first lens array. A second lens array having a lens. The second lens array is disposed at a position where a plurality of partial light beams emitted from the first lens array are condensed, and is located between a plurality of lens arrays including a plurality of small lenses. , Respectively, are formed with flat portions. The plurality of small lenses of the second lens array are formed in a polygonal shape other than the substantially rectangular shape according to the contour shape of the partial light beam collected by the corresponding plurality of small lenses of the first lens array. Have been.

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 which divides the light emitted from a light source into a plurality of partial light beams and superimposes each light beam substantially on the same illumination area. The present invention also relates to a projection display device capable of displaying a uniform and bright image using the illumination optical system.

[0002]

2. Description of the Related Art In a projection display device, a "light valve" is used.
Illumination light from an illumination optical system, which is applied to a light modulator, is modulated in accordance with image information (image signal) to be displayed, and the modulated light is projected on a screen to realize image display. .

It is preferable that an image displayed by such a projection display device is uniform and bright. However, the light emitted from the light source of the illumination optical system generally has the highest light intensity near the optical axis of the light source, and tends to decrease as the distance from the optical axis increases. If such light is used as illumination light as it is, an uneven image will be displayed on the projection display device. In order to solve such a problem, an integrator optical system has been conventionally used as an optical system for uniformly illuminating a light modulator which is an illumination area.

The integrator optical system divides light emitted from a light source into a plurality of partial light beams, and superimposes each of the plurality of divided partial light beams on an illumination area to provide uniform illumination. Is generally realized.

[0005]

The light source lamp used for the light source of the illumination optical system is ideally a point light source, but it is difficult to realize a point light source. Therefore, in the integrator optical system, when the light from the light source is divided into a plurality of partial light beams and superimposed on the illumination area, the use efficiency of the light emitted from the light source is reduced, and invalid light is reduced. Components may generate heat.

However, it is preferable that the image displayed by the projection display device is brighter, and it is desired that the illumination optical system used for the image display device has higher light use efficiency.

[0007] In general, the split optical system of the integrator optical system is configured using a lens array in which a plurality of small lenses are spread, but it is difficult to accurately manufacture this lens array. There is also a problem.

The present invention has been made to solve the above-mentioned problems in the prior art, and provides a technique capable of improving the efficiency of use of light of an illumination optical system and suppressing heat generation of constituent parts. The first purpose is to do so. It is another object of the present invention to provide a technique for easily manufacturing a lens array used for a split optical system. Further, a third object is to obtain a uniform and brighter projected image in the projection display device.

[0009]

In order to solve at least a part of the above problems, an illumination optical system according to the present invention provides an illumination optical system that illuminates a light incident surface of a predetermined optical device as an illumination area. A first lens array having a light source, a plurality of small lenses that divide light emitted from the light source into a plurality of partial light beams, and a plurality of small lenses of the first lens array. A second lens array having a corresponding plurality of lenslets;
Is arranged at a position where a plurality of partial light beams emitted from the first lens array are condensed, and between the plurality of lens rows constituted by the plurality of small lenses, , Each of which has a flat portion.

In the second lens array of the illumination optical system according to the present invention, a plane portion is formed between each of the plurality of lens rows composed of the plurality of small lenses. They are connected to each other via a plane portion and do not directly contact each other. Thus, the second lens array can be easily and accurately manufactured as compared with the case where the lenses are in direct contact with each other.

The plurality of small lenses of the second lens array may have a shape other than a substantially rectangular shape depending on the contour shape of the partial light beam condensed by the corresponding plurality of small lenses of the first lens array. Is preferably formed in a polygonal shape.

A partial light beam emitted from each small lens of the first lens array may not be used as effective illumination light unless it enters each corresponding small lens of the second lens array. As a result, the light use efficiency of the illumination optical system may decrease. On the other hand, in the illumination optical system of the present invention, a polygonal shape other than a substantially rectangular shape is used in accordance with the contour shape of the partial light beam condensed by the plurality of small lenses of the corresponding first lens array. Is formed, the partial light beam emitted from each small lens of the first lens array is prevented from entering another small lens adjacent to the corresponding small lens of the second lens array. be able to. Thereby, the light use efficiency of the illumination optical system can be improved. The “substantially rectangular shape” means not only a completely rectangular shape (rectangular or square) but also a case where the shape is not completely rectangular due to a design error or the like, and chamfering of some corners is added. Including the shape. That is, it means that the lens has a rectangular shape as a design concept.

Further, when it is assumed that a plurality of small lenses are spread and arranged without having the flat portion, the plane of the second lens array has the polarization conversion function of the plurality of small lenses. It is preferable that the optical system be formed on at least a part of a portion where light is incident on the invalid incidence surface of the optical system.

Light incident on the invalid incidence surface of the polarization conversion optical system is light that cannot be effectively used in the polarization conversion optical system. Therefore, in the above-described configuration, the light use efficiency of the illumination optical system is hardly reduced as compared with the case where it is assumed that a plurality of small lenses are laid out without a flat portion.

Here, when two reference axes passing through the center of the second lens array and perpendicular to each other are defined, at least one of the dividing lines for dividing the plurality of small lenses of the second lens array. It is preferable that the portion is formed so that the inclination with respect to the two reference axes increases as the distance from the two reference axes increases.

[0016] At least a part of the plurality of small lenses of the second lens array is one of the two reference lines.
It may have a trapezoidal shape divided by two division lines parallel to one reference line and two division lines inclined with respect to the other reference line.

According to the above arrangement, the small lenses of the second lens array can be formed according to the inclination of the contour shape of the incident partial light beam.

It is preferable that a light diffusing surface is formed on the surface of the flat portion.

With this configuration, since the light incident on the flat portion is diffused, the light incident on the ineffective incident surface of the polarization conversion optical system can be reduced. If the light incident on the ineffective incident surface of the polarization conversion optical system is reduced, heat generated by a polarizer such as a polarizing plate can be reduced.

Further, a light-shielding surface may be formed on the surface of the flat portion.

If a light-shielding surface is formed on the flat portion, light that enters the ineffective incident surface of the polarization conversion optical system can be easily shielded.

In the above illumination optical system, the first lens array has M rows (M is an integer of 2 or more) of small lens rows, and the second lens array has N rows (N is an integer). M
(A smaller integer of 1 or more), and a plurality of rows of partial light beams formed by a plurality of small lens rows in the first lens array are grouped into a smaller number of rows. By being incident on the second lens array,
The partial light beam split by the M small lens rows of the first lens array may be configured to be incident on the N small lens rows of the second lens array.

According to the above arrangement, the partial light beam split by the M small lens rows of the first lens array can be incident on the N small lens rows of the second lens array. Therefore, it is possible to widen the interval between the rows of partial light beams emitted from the second lens array. This allows
When an optical element corresponding to each column of the plurality of partial light beams is provided between the second lens array and a superimposing optical system that superimposes light emitted from the second lens array on an illumination area, Since the width of the optical element corresponding to each row in the column direction can be increased, the efficiency of light incidence on the optical element corresponding to each row can be improved. As a result, it is possible to improve the light use efficiency of the illumination optical system.

Here, the plurality of small lens rows in the first lens array are two small lens rows, and the two small lens rows are outer ones of the two small lens rows. 1
The position of each lenslet in the row, along the row direction,
One small lens row of the second lens array corresponding to the two small lens rows of the first lens array is arranged so as to be shifted from the position of each small lens in the row. It is preferable that the first small lenses corresponding to the outer one row of small lenses and the second small lenses corresponding to the inner one row of small lenses are alternately arranged.

In this way, the plurality of partial light beams emitted from the two small lens rows of the first lens array are
It is possible to easily enter the second lens array as a plurality of partial light beams arranged in a line.

In the illumination optical system, it is preferable that the illumination optical system includes an afocal optical system that converts an incident light beam into an exit light beam having a width smaller than the width of the incident light beam.

With the afocal optical system, the width of the light beam emitted from the illumination optical system can be reduced as compared with the case without the afocal optical system. Can be made smaller. Generally, the smaller the angle of incidence of the light beam incident on the optical element, the better the light use efficiency of the optical element. Therefore, according to the illumination optical system having the above configuration, the light use efficiency can be improved.

Here, a condenser lens having a condenser function for realizing the afocal optical system is provided near the first lens array, and a plurality of small lenses of the second lens array are provided. Preferably has a function of collimating light for realizing the afocal optical system.

According to the above configuration, an afocal optical system can be easily realized.

The projection display apparatus of the present invention has one of the above-mentioned illumination optical systems and a light incident surface as the illumination area, and modulates incident light from the illumination optical system according to an image signal. And a projection optical system for projecting the modulated light obtained by the light modulation device.

As described above, the illumination optical system according to the present invention comprises:
Light utilization efficiency can be improved as compared with the related art.
Therefore, in a projection display device incorporating the illumination optical system of the present invention, the brightness of a projected image can be improved.

Since the illumination optical system of the present invention has an integrator optical system using a split optical system, the light emitted from the light source has a large deviation in the light intensity distribution within the cross section of the light beam. Even if it is, it is possible to obtain illumination light with uniform brightness and without brightness or color unevenness, so that it is possible to obtain a projection image with uniform brightness over the entire projection surface and without brightness or color unevenness. it can.

The projection display apparatus further includes a color light separation optical system that separates the light emitted from the illumination optical system into at least two color lights, and modulates the color lights separated by the color light separation optical system. A plurality of the light modulation devices,
A color light synthesizing optical system that synthesizes the modulated light of each color after being modulated by each of the light modulation devices, and the synthesized light obtained by the color light synthesizing means is projected through the projection optical system. You can also

This makes it possible to project and display a brighter, more uniform, and more even color image than in the prior art.

[0035]

Embodiments of the present invention will be described below with reference to the drawings. In each of the following embodiments, unless otherwise specified, the traveling direction of light is the z-axis direction (direction parallel to the optical axis), and the direction at 12:00 when viewed from the z-axis direction is the y-axis direction (vertical direction). Direction) and the 3 o'clock direction is the x-axis direction (lateral direction)
And

A. FIG. 1 shows an overall configuration of the first embodiment.
FIG. 1 is a schematic configuration diagram of a main part of an illumination optical system 100 according to an embodiment, as viewed in plan. The illumination optical system 100 includes a light source 20
, A split optical system 30, a polarization conversion optical system 60, and a superimposing optical system (superimposing lens) 70. These optical elements 20, 30, 60, 70 are arranged such that their respective central axes coincide with the system optical axis 100 ax of the illumination optical system 100. The split optical system 30 and the superimposing optical system 70 constitute an integrator optical system for illuminating the effective illumination area ELA of the illumination area LA almost uniformly.

The light source 20 has a light source lamp 22 as a radiation light source for emitting a radial light beam, and a concave mirror 24 for emitting the radiation light emitted from the light source lamp 22 as a substantially parallel light beam. As the light source lamp 22, a high-pressure discharge lamp such as a metal halide lamp or a high-pressure mercury lamp is usually used. As the concave mirror 24, it is preferable to use a parabolic mirror. Note that, instead of a parabolic mirror, an elliptical mirror, a spherical mirror, or the like can be used.

The split optical system 30 includes the first lens array 4
0 and a second lens array 50. The first lens array 40 divides the substantially parallel light emitted from the light source 20 into a plurality of partial light beams, and collects the respective partial light beams to form a second lens array 50 and a polarization conversion optical system. It has a function of forming a condensed image near the system 60.

FIG. 2 is an explanatory diagram showing the first lens array 40. FIG. 2A shows the light incident surface side (light source 20 side).
It is the front view seen from. 2 (B) and 2 (C) are a plan view and a side view. The first lens array 40 has a configuration in which first convex small lenses 42 each having a substantially rectangular outline are arranged in a plurality of rows (M rows) and a plurality of columns (N columns). Note that the size of the lens array refers to the size of the entire small lens arrayed in a plurality of rows and columns, and does not include other peripheral portions. In addition, FIG.
An example where M = 8 and N = 6 is shown. First small lens 42
Has a substantially rectangular outer shape, but the optical axis of the lens is at the center of the lens. Hereinafter, such a lens whose optical axis coincides with the center of the lens is referred to as a “concentric lens”.

The outer shape of each first small lens 42 as viewed in the z-axis direction is usually set to be substantially similar to the shape of the effective illumination area ELA. For example, assuming a liquid crystal panel as an illumination area, if the aspect ratio (ratio of horizontal to vertical dimensions) of an image formation area, which is an effective illumination area, is 4: 3, the aspect ratio of the first small lens 42 Is also preferably set to 4: 3.

FIG. 3 is an explanatory diagram showing the second lens array 50. FIG. 3A is a front view as viewed from the light incident surface side (the first lens array 40 side). 3 (B) and 3 (C) are a plan view and a side view. The first lens array 40 has a configuration in which the same number of second small lenses 52 as the first small lenses 42 are arranged substantially in a matrix.

Here, a line passing through the central axis 50ax along the y-axis direction is defined as a reference line 50y, and x
A line along the axial direction is defined as a reference line 50x. The plurality of second small lenses 52 are arranged in three rows in both left and right directions (± x-axis directions) around the reference line 50y. Each of the columns on the right side has eight second vertical lines centered on the reference line 50x.
Are arranged. Each second small lens 5
2 have different shapes depending on the arrangement position. Each column on the left is the same as each column on the right. In the following, each column may be indicated by omitting the left side or the right side. In this case, the left or right column is shown.

Each row of the second small lenses 52 is not arranged by laying out the rows of the first small lenses 42 like the first lens array 40 (FIG. 2), but via a plane portion 54. Are spaced apart from each other. However, the first rows on the left and right are laid out and arranged. Note that the first rows on the left and right may also be arranged separately from each other via the plane portion 54 as in the other rows.

The vertical height L50 and the horizontal length L50 of the second lens array 50 are the vertical height H40 (FIG. 2) and the horizontal length L40 of the first lens array 40.
Is approximately equal to However, the length is reduced by a length corresponding to the plane portions 54 at the left and right ends.

The shape of the second small lens 52 of the second lens array 50 and the plane portion 54 will be described later.

FIG. 4 is a front view showing the second lens array 50 and the first lens array 40 from the z-axis direction. The dashed line shown in FIG.
Is shown. Further, the + mark indicates the optical axis of each first small lens 42 of the first lens array. The optical axis of each second small lens 52 of the second lens array 50 is configured to coincide with the optical axis of the corresponding first small lens 42 of the first lens array 40.

The direction of the lenses of the first lens array 40 need not be limited to the direction shown in FIG. 1, but may be arranged so as to have a convex surface on the exit surface side. The second lens array 50 does not need to be limited to the direction shown in FIG. 1 and may be arranged so as to have a convex surface on the exit surface side. Further, the superposition optical system 70 need not be limited to the direction shown in FIG. 1 and may be arranged so as to have a convex surface on the incident surface side.

The polarization conversion optical system 60 shown in FIG. 1 has a structure in which the second lens array 50 has a negative optical axis around the system optical axis 100ax.
The first where each partial light beam emitted from the x-axis direction enters
And a second polarization conversion element array 60b on which the respective partial light beams emitted from the + x-axis direction side are incident.

FIG. 5 shows a first polarization conversion element array 60a.
It is a perspective view which shows a structure of. The first polarization conversion element array 60a includes a light shielding plate 62, a polarization beam splitter array 64, and a λ / 2 phase difference plate 68 selectively disposed on a part of the light exit surface of the polarization beam splitter array 64. Have. The polarizing beam splitter array 64 includes a plurality of first translucent members 64 each having a columnar shape having a parallelogram cross section.
a are sequentially bonded, and the second and third translucent members 64b and 64c having a trapezoidal cross section are bonded to both ends thereof. The second and third translucent members 6
4b and 64c may be columnar bodies having the same cross section as the first translucent member 64a and having a parallelogram shape. Further, the section may be a columnar body having a substantially right triangle.

At the interface between the translucent members 64a, 64b, 64c, the polarization separation films 66a and the reflection films 66b are formed alternately. The polarization beam splitter array 64 is formed by bonding a plurality of glass plates having these films formed thereon such that the polarization separation films 66a and the reflection films 66b are alternately arranged, and is inclined at a predetermined angle. It is made by cutting. The polarization separation film 66a can be formed of a dielectric multilayer film, and the reflection film 66b can be formed of a dielectric multilayer film or an aluminum film.

The λ / 2 retardation plate 68 includes a polarization separation film 66 a
Alternatively, it is selectively disposed on the mapping portion in the x direction of the light exit surface of the reflection film 66b. In this example, a λ / 2 retardation plate 68 is selectively disposed at a portion in the x direction on the light exit surface of the polarization separation film 66a.

The light-shielding plate 62 has a plurality of light-shielding surfaces 62a and a plurality of opening surfaces 62b arranged in a stripe pattern. In this example, the light-shielding surface 62a is arranged in the x-direction image portion of the light incident surface of the reflection film 66b, and the aperture surface 62 is arranged in the x-direction image portion of the light incidence surface of the polarization separation film 66a.
b are arranged. Accordingly, of the light incident on the first polarization conversion element array 60a, the light that has passed through the opening surface 62b is incident only on the polarization splitting film 66a. Light shield plate 62
The light-shielding film (for example, a chromium film, an aluminum film, and a dielectric multilayer film) is partially formed on a flat transparent body (for example, a glass plate). A light-blocking flat plate provided with an opening or the like can be used.

FIG. 6 shows a first polarization conversion element array 60a.
FIG. 4 is an explanatory diagram showing the function of FIG. Opening surface 62b of light shielding plate 62
The unpolarized light beam (s-polarized light + p-polarized light) that has passed through
The light enters the polarization splitting film 66a of the polarization beam splitter array 64 and is divided into two types of linearly polarized light (s-polarized light and p-polarized light).
Is separated into Most of the p-polarized light is
a is transmitted as it is. On the other hand, most of s-polarized light is
The light is reflected by the polarization separation film 66a, further reflected by the reflection film 66b, and emitted in a state substantially parallel to the p-polarized light that has passed through the polarization separation film 66a as it is. The p-polarized light transmitted through the polarization separation film 66a is converted into s-polarized light by the λ / 2 retardation plate 68 and emitted. As a result, most of the non-polarized light incident on the first polarization conversion element array 60a is s.
The light is converted into polarized light and emitted. Of course, by forming the λ / 2 retardation layer 68 only on the exit surface of the light reflected by the reflection film 66b, almost all light beams can be converted into p-polarized light and emitted.

Here, assuming that the non-polarized light is directly incident on the reflection film 66b instead of the polarization separation film 66a, the first polarization conversion element array 60a outputs p light instead of s-polarized light.
The polarized light is emitted. As mentioned above,
In the present embodiment, light is prevented from being incident on the reflection film 66b by the light-shielding surface 62a of the light-shielding plate 62. Therefore, it is possible to prevent the unpolarized light from being incident on the reflection film 66b and emitting the undesired linearly polarized light from the first polarization conversion element array 60a.

Incidentally, one adjacent polarization splitting film 66a and one reflecting film 66b, and one λ / 2 retardation plate 68
Can be regarded as one row of polarization conversion elements. In the polarization conversion element array 60a, such polarization conversion elements are arranged in a plurality of rows in the x direction. In this embodiment, it is composed of three rows of polarization conversion elements.

The second polarization conversion element array 60b has a structure symmetrical to the polarization conversion element array 60a with the system optical axis 100ax as the axis of symmetry, and has the same function. .

As can be seen from the above description, the polarization conversion element array 6 corresponding to the light shielding surface 62a of the light shielding plate 62
The incident surfaces of the light beams 0a and 60b correspond to the ineffective incident surface of the polarization conversion optical system 60, and the light incident surfaces of the polarization conversion element arrays 60a and 60b corresponding to the aperture surfaces 62b of the light shielding plate 62 correspond to the polarization conversion optical system 60. Corresponds to the effective incident surface. In this embodiment, the reflection film 66b of the polarization conversion element arrays 60a and 60b is used.
Of the polarization separation film 66a corresponds to the effective incident surface.

The polarization conversion optical system 60 includes:
Instead of two polarization conversion element arrays 60a and 60b, 1
It is also possible to provide one polarization conversion element array.

The light emitted from the light source 20 in FIG.
Are divided into a plurality of partial light beams by the plurality of first small lenses 42 of the lens array 40. The plurality of divided partial light beams are condensed so as to be incident on the corresponding second small lenses 52 of the second lens array 50, and are located near the second lens array 50 and the polarization conversion optical system 60. Respectively form a condensed image. In FIG. 1, the central axis of each partial light beam is shown by a solid line for ease of explanation. The second lens array 50 is provided for each second small lens 5.
2 has a function of condensing light so that the light incident on the illumination area LA is effectively irradiated on the illumination area LA. The partial light beam emitted from each second small lens 52 enters the polarization splitting film 66 a of the polarization conversion optical system 60. As described above, the plurality of partial light beams incident on the polarization conversion optical system 60 are converted into almost one type of linearly polarized light, respectively. The plurality of partial light beams emitted from the polarization conversion optical system 60 are
0, and are substantially superimposed on the effective illumination area ELA of the illumination area LA by the superposition action of the superposition optical system 70. As a result, the effective illumination area ELA is almost uniformly illuminated with one kind of linearly polarized light.

The second lens array 50, the polarization conversion optical system 60, and the superposition optical system 70 are shown separated from each other. However, usually, in order to reduce the loss of light at each interface, it is preferable that they are closely arranged by bonding each other with an adhesive or the like. Further, the superposition optical system 70 can be omitted.

B. Function of the second lens array 50: In the following, in order to describe the function of the second lens array 50,
First, the function of the lens array 50M of the comparative example shown in FIG. 7 will be described. The lens array 50M of this comparative example is the same as the second lens array 50 shown in FIG. 3 except that no flat portion is formed between the small lens rows.

FIG. 8 is an explanatory diagram showing a condensed image formed by the first lens array 40. The condensed image in the figure is represented by the light intensity indicated by the contour lines. FIG. 8 shows only the condensed image of the １ ／ portion at the upper right of the second lens array 50. Usually,
Since the characteristics of the light emitted from the light source 20 are symmetric about the optical axis, the left half condensed image is left-right symmetric with respect to the right half condensed image, and the lower half condensed image is the upper half. Is vertically symmetrical with respect to the condensed image.

Since the light source lamp 22 constituting the light source 20 is not a point light source, the condensed image of each partial light beam also has a shape corresponding to the shape of the light source lamp. In this example, it has an elongated shape (substantially elliptical shape or approximately elliptical shape) along a direction (hereinafter, referred to as “radiation direction”) connecting the system optical axis 100ax and the position where the condensed image is formed. I have. In addition, since the light emitted from the light source 20 tends to have more excellent parallelism as the distance from the system optical axis 100ax is increased, the overall size of the condensed image in the periphery tends to be smaller.

In such a case, the second lens array is
Assuming that the lens array has the same shape as the first lens array 40, as shown in FIG. 8, there are cases where many portions where the condensed image by each partial light beam protrudes from the corresponding small lens occur. (Indicated by oblique lines in the figure). The split optical system constituted by the first lens array and the second lens array is set so that the light beam passing through the corresponding small lens is irradiated to the effective illumination area ELA via the superimposing optical system 70. Have been. Therefore, the light beam incident on the lens other than the corresponding small lens may not be effectively irradiated on the effective illumination area ELA. As described above, if there are many protruding portions, the light use efficiency of the illumination optical system is reduced accordingly.

FIG. 9 is an explanatory diagram showing the relationship between the condensed image formed by the first lens array 40 at a position near the second lens array 50M, which is a comparative example, and the second lens array 50M. . The inclination of the long axis of each condensed image with respect to the x-axis depends on the radiation direction, that is, the system optical axis 100a.
It changes according to the angle between the line connecting x and the center of each condensed image and the x-axis. For example, the condensed image in the first row from the bottom in FIG. 9 is formed such that the major axis is along the x-axis direction.
Is formed so that the major axis is along the y-axis direction. The condensed images in the second and third rows of the second and third columns are formed such that the major axis is inclined according to the position. Therefore, the second lens array 50M has a trapezoidal shape corresponding to each position so as to efficiently separate each condensed image according to the inclination of the long axis of the condensed image formed by each partial light beam. It is constituted by a second small lens 52M. Specifically, each condensed image is divided as follows by each second small lens 52M of the second lens array 50M.

Each row is sectioned parallel to the y-axis. Each row is divided by a different inclination (inclination with respect to the x-axis) according to the inclination of the long axis of the condensed image. For example, the inclination of the long axis of the condensed image increases in a row farther from the system optical axis 100ax, and accordingly, the inclination of the dividing line between the rows increases. However, each condensed image in the first column from the system optical axis 100ax has its major axis almost aligned with the y-axis. Although it has a slight inclination, it is divided substantially along the x-axis.

In the case of the second lens array 50M configured as described above, each condensed image can be prevented from protruding from the corresponding second small lens 52M.
The efficiency of the illumination optical system can be improved as compared with the case where a lens array formed of substantially rectangular small lenses similar to the first lens array 40 is used as the second lens array.

Note that the second lens array 50M is
Second lens 52M constituting the lens array 50M of FIG.
Has a trapezoidal shape, but the present invention is not limited to this. In the above description, the characteristics of the light emitted from the light source are described as being symmetric about the system optical axis 100ax. However, the present invention can be applied to a case where the characteristics are not symmetric. In short, the second lens array is a small lens having a polygonal shape other than a rectangular shape according to the contour shape such as the size and inclination of the corresponding condensed image so as to efficiently partition each condensed image. With such a configuration, each condensed image can be prevented from protruding from the corresponding second small lens, so that the second lens array has a substantially rectangular shape similar to that of the first lens array 40. The efficiency of the illumination optical system can be improved as compared with the case where a lens array constituted by small lenses is used.

FIG. 9 shows a second lens array 50M formed by the second lens array 50M and the first lens array 40.
FIG. 5 is an explanatory diagram showing a relationship with a converged image formed at a position near M. The inclination of the long axis of each condensed image with respect to the x axis is
The angle between the radiation direction and the x axis, that is, the system optical axis 1
It changes according to the angle between the direction connecting 00ax and the center of each condensed image and the x-axis. For example, the condensed image in the first row from the bottom in FIG. 9 is formed such that the major axis is along the x-axis direction,
The condensed image in the first column from the left in FIG. 9 is formed such that the long axis is along the y-axis direction. The condensed images in the second and third rows of the second and third columns are formed such that the major axis is inclined according to the position. Therefore, the second lens array 50M adjusts the inclination of the long axis of the condensed image formed by each partial light beam,
A trapezoidal second small lens 52M corresponding to each position is configured to efficiently separate each condensed image. Specifically, each second small lens 52M of the second lens array 50M is divided as follows.

The dividing line for dividing each row of the second lens array 50M is divided by a straight line parallel to the y-axis direction.
It should be noted that the dividing line for dividing each column is not necessarily a straight line, and may not be parallel to the y-axis. However, a straight line parallel to the y-axis direction is preferable for the following reasons.

In the lower part of FIG. 9, a polarization conversion optical system 60 is shown for reference. Light shielding surface 62 of polarization conversion optical system 60
a and the opening surface 62b are arranged for each column of the second lens array 50M. Also, the opening surfaces 62b of each row
Are arranged such that partial light beams emitted from the second lens array 50 are respectively incident thereon,
a is arranged between the opening surfaces 62b of each row. Therefore, it is preferable that the position in the x-axis direction of the division line along the y-axis dividing each column is within the width of the light-shielding surface 62a in the x-axis direction. Therefore, each row of the second lens array 50M is
It is divided by a straight line parallel to the y-axis direction. This makes it easy to divide each column.

Each row of the second lens array 50M is divided by a different inclination (inclination with respect to the x-axis) according to the inclination of the long axis of the condensed image. For example, the system optical axis 100a
The inclination of the long axis of the condensed image increases as the distance from the row x increases, and accordingly, the inclination of the dividing line between the rows increases.
However, since each condensed image in the first column stands with its major axis almost along the y-axis, the dividing line between each row is slightly inclined according to the inclination of the major axis of each condensed image. , But are generally sectioned along the x-axis.

The second lens array 50 can be regarded as being divided as follows. That is, assuming that a reference line (reference axis) parallel to the x-axis and passing through the system optical axis 100ax is 50x and a reference line (reference axis) parallel to the y-axis is 50y, the first line along the reference line 50x and The division line of the second small lens other than the division line dividing the second small lens 52 in the first row along the reference line 50y becomes 2 as the distance from the at least two reference lines 50x and 50y increases.
The inclination with respect to the two reference lines 50x and 50y is formed to be large.

When the second lens array 50M configured as described above is used, each condensed image can be prevented from protruding from the corresponding second small lens 52M. The efficiency of the illumination optical system can be improved as compared with the case where a lens array having the same shape as the first lens array is used as the array.

In the above description, the case where the second small lens 52M constituting the second lens array 50M has a trapezoidal shape is shown, but the present invention is not limited to this. For example, the shape may be a triangle, a pentagon, or a rhombus. Further, in the above description, the characteristics of the light emitted from the light source 20 are described as being symmetrical about the system optical axis 100ax. In short, the second lens array is a small lens having a polygonal shape other than a rectangular shape according to the contour shape such as the size and inclination of the corresponding condensed image so as to efficiently partition each condensed image. What is necessary is just to comprise.

In the second lens array 50 of the present embodiment, the flat lens 54 has an end in the direction of each small lens M of the second lens array 50M of the comparative example. This variant has the following advantages.

When manufacturing a lens array in which small lenses are spread all over like the second lens array 50M, the shape of the boundary where the small lenses contact each other is likely to deteriorate. For example, the slope of the curved surface that is in contact may become smaller or larger, which results in the boundary portion becoming thicker or thinner.
In some cases, this boundary portion becomes too thin and separates. In order to prevent such separation, a lens array having a certain thickness is usually manufactured in consideration of thinning. Such a problem is less likely to occur when the lens surface and the plane contact each other than when the lens surfaces contact each other.

Accordingly, the second lens array 50 is manufactured because the second small lenses 52 along the direction in which the light-shielding surface 62a and the opening surface 62b are aligned with each other via the plane portion 54. Is easy.

Further, as described above, the end of each small lens 52M in each column of the second lens array 50M of the comparative example in the column direction is located at a position corresponding to the light shielding surface 62a of the polarization conversion optical system 60. . Since the light-shielding surface 62a is an invalid incident surface, even if there is no portion of each small lens 52M that emits light incident on the light-shielding surface 62a, the light use efficiency of the entire illumination optical system does not change. Therefore, the second lens array 50 of the present embodiment is a portion of the second lens array 50M of the comparative example that emits light incident on the light-shielding surface 62a, that is, the second lens array 50M of each column of the second lens array 50M. The end portion is a flat portion 54.

The light shielding surface 6 of each of the small lenses 52M
It is not necessary to make the entire part that emits the light incident on 2a a flat part, and at least a part may be made a flat part. In other words, when it is assumed that the plane portion of the second lens array does not have such a plane portion and a plurality of small lenses are spread and arranged, the invalidity of the polarization conversion optical system among the plurality of small lenses is considered. What is necessary is just to form at least part of the part which makes light incident on an incident surface. In this case, the second lens array can be easily manufactured. The width of the flat portion may be at least about 2 mm or more.

If a light-shielding surface is formed on the surface of the flat portion 54, the light-shielding plate 62 provided on the polarization conversion element arrays 60a and 60b can be omitted. This light-shielding surface can be realized by attaching a light-shielding plate or forming a light-shielding film on the surface of the flat portion 54. Also, the flat portion 54
If a diffusion surface is formed on the surface of the light-emitting device, the amount of light passing through the flat portion 54 and entering the light-shielding surface 62a of the polarization conversion element arrays 60a and 60b can be reduced. Thereby, the light shielding plate 62 provided in the polarization conversion element arrays 60a and 60b is provided.
Can also be omitted. Such a diffusing surface can be formed, for example, by forming the surface of the flat portion 54 with sand.

As described above, the illumination optical system 100 of the present embodiment can improve the efficiency of the illumination optical system by using the second lens array 50. The second lens array 50 is easy to manufacture.

C. Second Embodiment FIG. 11 is a schematic configuration diagram of a main part of an illumination optical system 100A according to a second embodiment as viewed in plan. This illumination optical system 100A is obtained by changing the split optical system 30 and the polarization conversion optical system 60 of the first embodiment, and the other configuration is the same as that of the first embodiment.

The split optical system 30A according to the second embodiment includes a first lens array 40A and a second lens array 50A.

FIG. 11 is an explanatory diagram showing the first lens array 40A. FIG. 11A is a perspective view of the first lens array 40A. FIG. 11B is a front view seen from the light incident surface side (the light source 20 side). FIGS. 11C and 11D are a plan view and a bottom view, respectively, and FIG.
(D) is a left side view and a right side view. First
As in the first lens array 40 (FIG. 2) of the first embodiment, a first convex small lens 42A having a substantially rectangular contour is spread and arranged in a plurality of rows and a plurality of columns. It has the structure which was done. However, the number of rows in each column (the number of small lenses included in each column) does not necessarily need to be the same.

Here, a line passing through the central axis 40Aax in the y-axis direction is defined as a reference line 40Ay, and a line passing through the central axis 40Aax in the x-axis direction is defined as a reference line 40Ax. The plurality of first small lenses 42A are arranged in three rows in both left and right directions (± x-axis directions) around the reference line 40Ay. In each of the first and second columns on the right side, eight first small lenses 42A are arranged vertically with respect to the reference line 40Ax, and seven in the third column on the right side. The first small lenses 42 are laid out and arranged. Further, the first small lenses 42 in each row of the third column on the right side are arranged exactly between rows of the first small lenses 42 in each row of the second column on the right side. Each column on the left is the same as each column on the right. In the following, each column may be indicated by omitting the left side or the right side. In this case, the left or right column is shown.

In FIG. 11 (B), the symbols .times., .Times., And + indicate the positions of the optical axes of the first small lenses 42A. Each first
The position of the optical axis of the small lens 42A is set to a different position according to the arrangement position. The mark indicates the position of the optical axis of the first small lens 42A in the first column.
The + mark indicates the position of the optical axis of the first small lens 42A in the second row, and the X mark indicates the position of the optical axis of the first small lens 42A in the third row.

FIG. 12 is an explanatory diagram showing the second lens array 50A. FIG. 12A is a perspective view of the second lens array 50A. FIG. 12B is a front view as viewed from the light incident surface side (the first lens array 40A side). 12C and 12D are a plan view and a bottom view, and FIGS. 12E and 12D are a left side view and a right side view.

Here, a line passing through the central axis 50Aax in the y-axis direction is defined as a reference line 50Ay, and a line passing through the central axis 50Aax in the x-axis direction is defined as a reference line 50Ax. The plurality of second small lenses 52A are arranged in two rows in both the left and right directions (± x-axis directions) around the reference line 50Ay. In the first column on the right side, eight second small lenses 52A are arranged in the vertical direction about the reference line 50Ax. In the second column on the right side, 15 second small lenses 52
A is arranged. At the end in the column direction of each column, a plane portion 54A is provided similarly to the second lens array 50 (FIG. 3) of the first embodiment. The same applies to each column on the left.
However, the first rows on the left and right are laid out and arranged.
Note that the left and right first rows are also similar to the other rows in the plane portion 54.
It may be arranged to be spaced apart through A. Each of the second small lenses 52A has a different shape depending on the arrangement position. In the following, each column may be indicated by omitting the left side or the right side. In this case, the left or right column is shown.

The height in the vertical direction and the length L50A in the horizontal direction of the second lens array 50A are equal to those of the first lens array 4A.
It is approximately equal to a vertical height H40A (FIG. 2) and a horizontal length L40A of zero. However, the flat portions 54A at both left and right ends
Is reduced by a length corresponding to.

The polarization conversion optical system 60A has a polarization conversion element array having polarization conversion elements of the number of rows corresponding to the number of rows of the second lens array 50A symmetrically with respect to the system optical axis 100Aax. In this embodiment, a polarization conversion element array one row smaller than the polarization conversion element array 60a (FIG. 5) is used.

Similarly to the second lens array 50 of the first embodiment, the end of each second small lens of the second lens array 50N shown in FIG. Part. Hereinafter, in order to facilitate the description of the second lens array 50A, the second lens array 50A will be described as a second lens array 50N.

FIG. 13 is an explanatory diagram showing the second lens array 50N. FIG. 13A is a perspective view of the second lens array 50N. FIG. 13B is a front view as viewed from the light incident surface side (the first lens array 40A side). FIGS. 13C and 13D are a plan view and a bottom view, respectively, and FIGS. 13E and 13D are a left side view and a right side view.

The second lens array 50N has the same shape as the second lens array 50M having the first function described in the first embodiment. 52M has a configuration in which a plurality of rows and a plurality of columns are arranged. The second lens array 50N has the same number of second small lenses 52N as the first small lenses 42A so as to correspond to each first small lens 42A of the first lens array 40A. However, the first lens array 40
The small lenses of the second lens array 50N corresponding to the small lenses in the second and third rows of A are arranged only in the second row, that is, in one row. Second lens array 50N
Vertical height H50N and horizontal length L50N
Is the vertical height H40A of the first lens array 40A.
(FIG. 11B) and the length L40A in the horizontal direction. Note that a line passing through the central axis 50Nax along the y-axis direction is referred to as a reference line 50Ny, and a line passing through the central axis 50Nax along the x-axis direction is referred to as a reference line 50Nx.

In FIG. 13B, the symbols .times., .Times., And + indicate the positions of the optical axes of the second small lenses 52N. Each second
The position of the optical axis of the second small lens 52N is set to a different position according to the arrangement position. The mark indicates the position of the optical axis of the second small lens 52N in the first column. The + mark indicates the position of the optical axis of the second small lens 52N in the odd-numbered row from the second column, and the X mark indicates the position of the optical axis of the second small lens 52N in the even-numbered row.

In the following, the second lens array 50N
In order to facilitate the description, first, an example in which a virtual second lens array 50B shown in FIG. 14 is used will be described. FIG. 14A is a front view of the light of the second lens array 50B as viewed from the incident surface side (the first lens array 40A side). FIG. 14B shows a bottom view.

The second lens array 50B has a configuration in which plano-convex second small lenses 52B having a substantially rectangular outline are arranged in a plurality of rows and columns. The second lens array 50B has the same number of second small lenses 52B as the first small lenses 42A so as to correspond to each first small lens 42A of the first lens array 40A. However, as described below, a second lens array corresponding to the small lenses in the second and third columns of the first lens array 40A.
The small lenses of the lens array 50B are only in the second row,
That is, they are arranged in one line. Second lens array 5
0B vertical height H50B and horizontal length L50
B is substantially equal to the vertical height H40A (FIG. 11B) and the horizontal length L40A of the lens array 40A. Note that a line passing through the central axis 50Bax along the y-axis direction is referred to as a reference line 50By, and a line passing through the central axis 50Bax along the x-axis direction is referred to as a reference line 50Bx.

The plurality of second small lenses 52B are connected to the reference line 5
Two rows are arranged in both left and right directions (± x-axis direction) with 0By as the center. In the first column on the right side, the same number of the second small lenses 52 as the first small lenses 42A (FIG. 11B) arranged in the first column on the right side of the first lens array 40A are provided.
B are arranged. That is, four rows of the second small lenses 52 in both the upper and lower directions around the reference line 50Bx.
B are arranged. The second column on the right side has the same number as the sum of the numbers of the first small lenses 42A arranged on the second and third columns on the right side of the first lens array 40A, that is, fifteen second lenses. The small lenses 52B are arranged. The second small lenses 52B in odd-numbered rows in the second column on the right side are the first small lenses 42A in the second column on the right side of the first lens array 40A.
It corresponds to. Further, the second small lenses 52B in the even rows
Corresponds to the first small lens 42A in the third column on the right side of the first lens array 40A.

The entire length of each row on the right side in the y-axis direction is set to be the same. However, the length of each second small lens 52 in the y direction as viewed from the z-axis direction has a different size depending on its position. The second lens array 50B
Each of the second small lenses 52A on the left side is similar to that on the right side.

[0100] In Fig. 14A, the marks-,-and + indicate the position of the optical axis of each second small lens 52B. The mark indicates the position of the optical axis of the second small lens 52B in the first column. The + mark indicates the position of the optical axis of the second small lens 52B in the odd row from the second column, and the x mark indicates the optical axis of the second small lens 52B of the second small lens 52A in the even row. The position of is shown. Similarly to the first small lenses 42A of the first lens array 40A, the position of the optical axis of each second small lens 52B is set to a different position according to the arranged position. This is for the following reason.

FIG. 15 is a plan view showing the positional relationship between the first lens array 40A and the second lens array 50B. + X side from the system optical axis 100Aax and + x
Since the configuration is symmetrical with the direction side, a description will be given here on the −x direction side.

The second lens array 50B has substantially the same size as the first lens array 40A.
1 and the first lens array 40 as shown in FIG.
One column is smaller than the number of columns of A. Therefore, the second small lenses 52B (52Ba to 52B) of the second lens array 50B
c) shows the first small lens 4 of the first lens array 40A.
The width of each small lens in the x-axis direction is larger than that of 2A (42Aa to 42Ac). Therefore, the first small lenses 42Aa to 42Aa of the first to third columns of the first lens array 40A are formed.
42Ac is the second lens array 50B corresponding to the second lens array 50B.
Each of the small lenses 52Ba to 52Bc is configured with a lens having an optical axis at a different position so that each of the partial light beams is incident. In addition, the second small lenses 52Ba of the second lens array 50B corresponding to the first small lenses 42Aa to 42Ac of the first lens array 40A.
52Bc are also constituted by lenses having optical axes at different positions. Further, the first lens array 40
The second small lens 52Bb corresponding to the second column of A and the third
As described above, the second small lenses 52Bc corresponding to the rows are arranged in one row so as to form the third rows of the second lens array 50. More specifically, the second small lenses 52Bc and the second small lenses 52Bb are alternately arranged.

Each of the partial light beams emitted from each of the first small lenses 42Aa to 42Ac of the first lens array 40A is deflected according to the position of each lens, and the corresponding partial light beam of each of the second lens arrays 50B. 2 small lenses 52Ba-52
Bc. Each of the second small lenses 52Ba to 52Bc
Each of the incident partial light beams is deflected such that its central axis is substantially parallel to the system optical axis 100Aax.

FIG. 16 is an explanatory diagram showing a condensed image formed at a position near the second lens array 50B by the first lens array 40A. FIG. 16 shows only the upper right half condensed image similarly to FIG.

The condensed images of light formed near the second lens array 50B are arranged in two rows as shown in FIG. 16, so that three rows of condensed images are formed within the same width. Compared with the case, the interval between the rows of the condensed images can be increased. This has the following advantages.

As described with reference to FIGS. 5 and 6, the polarization conversion optical system includes the adjacent polarization separation film 66a and reflection film 6a.
6b are arranged in a number corresponding to the number of columns of the second lens array, and the light incident on the polarization splitting film 66a included in the polarization conversion element is substantially 1
It converts the light into linearly polarized light. Therefore, the higher the efficiency of light incidence on the polarization separation film 66a, the better the light use efficiency.

When the splitting optical system 30B is constituted by the first lens array 40A and the second lens array 50B, the interval between the columns of the condensed images (the interval between the partial light beams) can be increased. The width of the polarization conversion element in the column direction can be increased. Thereby, the width of the polarization splitting film 66a included in the polarization conversion element can be increased, so that the efficiency of incidence of light emitted from the second lens array 50B to the polarization conversion optical system 60A can be improved. . As a result, the light use efficiency of the illumination optical system can be improved.

If the interval between the columns of the condensed images is the same as the interval between the condensed images when the number of columns is not reduced, the size of the second lens array and the polarization conversion optical system can be reduced. In this case, the incident angle of the light beam incident on the optical element arranged at the subsequent stage can be reduced. The smaller the incident angle of the light beam incident on the optical element, the higher the light use efficiency of the optical element, and as a result, the light use efficiency of the illumination optical system can be improved.

The second lens array 50N has both the function of the second lens array 50B and the function of the second lens array 50M of the first embodiment. That is, the condensed image formed in the vicinity of the second lens array 50B may have a portion that protrudes from the corresponding small lens depending on the position, as shown in FIG. Therefore, as shown in FIG. 17, the second lens array 50N has a polygonal second shape formed so as to divide the condensed image formed by each partial light beam according to the shape of the condensed image. Of the small lens 52N. Thereby, it is possible to suppress the condensed image of each partial light beam from protruding from the corresponding second small lens 52N of the second lens array 50N, so that the virtual second lens array 50B is used. As compared with the case, the light use efficiency of the illumination optical system can be improved.

The second lens array 5 of the embodiment of the present embodiment
0A indicates that the end of each second small lens of the second lens array 50N in the column direction is a plane portion.
Has the same function as the lens array 50N. Therefore, the illumination optical system 100A of the present embodiment is different from the illumination optical system 100A in which a lens array including substantially rectangular small lenses similar to the first lens array 40 is used as the second lens array. Efficiency can be improved.

Further, the second lens array 50A is easy to manufacture because the end of each second small lens 52N in the column direction is constituted by the flat portion 54. Further, there are the following advantages.

FIG. 18 shows the second small lenses 52N in the second row from the second column of the second lens array 50N and the two rows from the second column in the second lens array 50A. It is a schematic side view which shows the 2nd small lens 52A of an eye. FIG.
As can be seen from (A) and (B), the end of the second small lens 52 of the second lens array 50A corresponds to the end of the second small lens 52N of the second lens array 50N. A flat portion 54A is formed in the portion. For this reason,
The degree to which the lens surface of the second small lens 52A of the second lens array 50A sinks into the substrate 56 can be made smaller than the degree to which the lens surface of the second small lens 52N sinks into the substrate 56. Thereby, there is an advantage that the thickness of the substrate portion 56 can be reduced as compared with the second lens array 50N.

In the illumination optical system 100A of this embodiment, a condensed image formed by the leftmost two columns and the rightmost two columns of the plurality of partial light beams divided by the first lens array 40A. Are arranged in a line. However, it is not limited to this. For example, the condensed images formed by the partial light beam bundles of three or more rows may be arranged in one row. Further, it is not necessary to combine the two rows at the left and right ends into one row, and only one of them may be combined into one row. Further, it is not necessary to have the last two rows. Further, three rows may be combined into two rows. That is, in general, a plurality of rows of partial light beams formed by a plurality of small lens rows in the first lens array may be collected into a smaller number of rows and incident on the second lens array. The above modification can be similarly applied to the following third embodiment.

E. Third Embodiment FIG. 19 is a schematic configuration diagram of a main part of an illumination optical system 100C according to a third embodiment as viewed in plan. This illumination optical system 100C is obtained by changing the split optical system 30A and the polarization conversion optical system 60A of the second embodiment, and the other configuration is the same as that of the second embodiment.

The split optical system 30C according to the third embodiment includes a first lens array 40C and a second lens array 50C.

FIG. 20 is an explanatory diagram showing the first lens array 40C. FIG. 20A is a perspective view of the first lens array 40C. FIG. 20B is a front view seen from the light incident surface side (the light source 20 side). FIGS. 20C and 20D are a plan view and a bottom view, respectively, and FIG.
(D) is a left side view and a right side view. First
Is larger than the first lens array 40A on the side opposite to the surface on which the first small lenses 42A of the first lens array 40A (FIG. 11) of the second embodiment are formed. It has a configuration provided with a lens 44. The condenser lens 44 is a plano-convex lens.

The second lens array 50C has a second lens array 50C corresponding to the size of the light beam condensed by the condenser lens 44.
The second lens array 50A (FIG. 12) of the embodiment has a shape that is entirely reduced. However, each second small lens 5
2C is configured to have both the function of returning the light condensed by the condenser lens 44 to parallel light and the function of each second small lens 52A of the second lens array 50A.

FIG. 21 is an explanatory diagram showing the function of the condenser lens 44 of the first lens array 40C. FIG. 21 shows a light source 20, a condenser lens 44, and a first lens array 40.
D and a second lens array 50 </ b> D are sequentially arranged. Each first small lens 42D of the first lens array 40D is the same concentric lens as the first small lens 42 constituting the lens array 40 of the first embodiment. The second lens array 50D is the first lens array of the first lens array.
Is composed of a second small lens 52D smaller than the small lens 42D. The position of the optical axis of each of the second small lenses 52D differs depending on the arrangement position.

The substantially parallel light emitted from the light source 20 becomes condensed light by the condensing action of the condensing lens 44. The condensed light emitted from the condenser lens 44 is divided into a plurality of partial light beams by each first small lens 42D of the first lens array 40D. The partial light beam emitted from each first small lens 42D is deflected such that the central axis of each partial light beam is inclined toward the system optical axis 100Dax by the light condensing function of the light condensing lens 44, and the second lens The light enters the corresponding second lenslet 52D of the array 50D. The second small lens 52D has a function of deflecting the central axis of the incident partial light beam so as to be parallel to the system optical axis 100Dax. As a result, the entire light emitted from the second lens array 50D is smaller than the entire width of the light that has entered the condenser lens 44. As described above, the condenser lens 44 and the second lens array 50 </ b> D
4 functions as an afocal optical system that converts the light beam incident on the light beam into a light beam having a width smaller than the width of the light beam. The condensing lens 44 has a condensing function for realizing an afocal optical system, and the second lens array 50D has a function for collimating light for realizing an afocal optical system. I have.

The light emitted from the afocal optical system is
Since the size is reduced as a whole, the angle of incidence on the optical system arranged at the subsequent stage can be reduced as compared with the case without the afocal optical system. As described in the second embodiment, the smaller the incident angle of the light beam incident on the optical element, the better the light use efficiency of the optical element. Therefore, by using the afocal optical system, the light use efficiency can be improved.

The condenser lens 44 of the first lens array 40C of this embodiment corresponds to the condenser function of the afocal optical system, and the second lens array 50C is the second lens array 50A of the second embodiment. It has the function of FIG. 12 and the function of the second lens array 50D (FIG. 21), that is, the function of collimating the light of the afocal optical system. Therefore, according to the illumination optical system 100C of the present embodiment, similarly to the second embodiment, it is possible to increase the efficiency of incidence on the polarization conversion optical system 60C disposed downstream of the second lens array 50C. In addition, the function of the afocal optical system can improve the light use efficiency of the optical element disposed downstream of the second lens array 50C. As a result, also in the illumination optical system 100C of the present embodiment, the light use efficiency can be improved. Further, it is easy to manufacture the second lens array 50C used for the illumination optical system 100C.

F. Projection Display Device: FIG. 22 is a schematic configuration diagram of a main part of a projection display device 1000 using the illumination optical system 100C of the present invention, as viewed in plan. This projection display apparatus 1000 uses the illumination optical system 100C of the present invention.

The projection display apparatus 1000 includes the illumination optical system 1
00C, the color light separation optical system 200, and the relay optical system 22
0 and three liquid crystal light valves 300R, 300G, 3
00B, a cross dichroic prism 320, and a projection optical system 340. Projection display device 100
0 indicates that the light emitted from the illumination optical system 100C is separated into three color lights of red (R), green (G), and blue (B) by a color light separation optical system 200, and each of the separated color lights is a liquid crystal. The light is modulated according to image information (image signal) through the light valves 300R, 300G, and 300B, and the modulated color lights are combined by the cross dichroic prism 320, and an image is displayed on the screen SC via the projection optical system 340. Is what you do.

As described above, the illumination optical system 100C
Illumination light of linearly polarized light (s-polarized light in the above example) whose polarization directions are aligned is emitted to illuminate the liquid crystal light valves 300R, 300G, and 300B that are the illumination area LA. Each of the liquid crystal light valves 300R, 300G, and 300B includes a liquid crystal panel and a polarizing plate disposed on the light incident / exit surface side. The polarizing plate disposed on the light incident surface of the liquid crystal panel is for further increasing the degree of polarization of the illumination light, and the polarization direction of the linearly polarized light emitted from the illumination optical system 100C is changed by these polarizing plates. In the transmission axis direction. By doing so, it is possible to further increase the purity (degree of polarization) of the linearly polarized light included in the illumination light emitted from the illumination optical system 100C. When the degree of polarization of the illumination light emitted from the illumination optical system 100C is extremely high, the polarizing plate disposed on the light incident surface side can be omitted.

The color light separation optical system 200 includes two dichroic mirrors 202 and 204 and a reflection mirror 208, and converts a light beam emitted from the illumination optical system 100 into three colors of red, green and blue. It has the function of separating into color light.
The first dichroic mirror 202 is connected to the illumination optical system 10.
While transmitting the red light component of the light emitted from 0, it reflects the blue light component and the green light component. The red light R transmitted through the first dichroic mirror 202 is reflected by the reflection mirror 208 and emitted toward the cross dichroic prism 320. The red light R emitted from the color light separation optical system 200 reaches the liquid crystal light valve 300R for red light through the field lens 232. The field lens 232 converts each partial light beam emitted from the illumination optical system 100 into a light beam parallel to its central axis. The same applies to the field lenses 234 and 230 provided in front of the other liquid crystal light valves.

Of the blue light B and the green light G reflected by the first dichroic mirror 202, the green light G is reflected by the second dichroic mirror 204 and passes from the color light separation optical system 200 to the cross dichroic prism 3.
Injected toward 20. The green light G emitted from the color light separation optical system 200 reaches the liquid crystal light valve 300G for green light through the field lens 234. on the other hand,
Blue light B transmitted through the second dichroic mirror 204
Are emitted from the color light separation optical system 200 and enter the relay optical system 220. The blue light B incident on the relay optical system 220 is incident on the incident-side lens 222, the relay lens 226,
4,228 and emission side lens (field lens) 2
The liquid crystal light valve 300B for blue light passes through 30. Here, the reason why the relay optical system is used for the blue light B is to prevent a decrease in light use efficiency because the optical path length of the blue light B is longer than the optical path lengths of the other color lights. is there. That is, it is for transmitting the blue light incident on the incident side lens 222 to the exit side lens 230 as it is.
The distances from the superimposing optical system 70 of the illumination optical system 100 to the liquid crystal light valve 300R, the liquid crystal light valve 300G, and the incident side lens 222 are set to be substantially equal.

Three liquid crystal light valves 300R, 300
G and 300B have a function as a light modulator that forms an image by modulating three color lights in accordance with a given image signal. Cross dichroic prism 32
0 is a liquid crystal light valve 300R, 300G, 300B
Has a function as a color light combining optical system that forms a color image by combining three color lights modulated by passing through. In addition,
The cross dichroic prism 320 includes a red light reflecting dichroic surface 321 on which a dielectric multilayer film for reflecting red light is formed, and a blue light reflecting dichroic surface 322 on which a dielectric multilayer film for reflecting blue light is formed. An X-shape is formed at the interface between the four right-angle prisms. The three color lights are combined by the red light reflecting dichroic surface 321 and the blue light reflecting dichroic surface 322 to form combined light for projecting a color image.
The combined light generated by the cross dichroic prism 320 is emitted toward the projection optical system 340. The projection optical system 340 projects the combined light emitted from the cross dichroic prism 320 and displays a color image on the screen SC. Note that a telecentric lens can be used as the projection optical system 340.

The projection display apparatus 1000 includes an illumination optical system 10 using an integrator optical system having high light use efficiency.
Since 0C is used, a uniform and bright image can be displayed.

In the above embodiment, the illumination optical system 100
Although the case where C is used is described as an example, the illumination optical system of another embodiment can be used.

In the projection display apparatus 1000,
The case where the illumination optical system 100C of the present invention is applied to a projection display device that projects a color image using three liquid crystal panels (liquid crystal light valves) has been described, but is not limited thereto. The illumination optical system of the present invention can be used as an illumination optical system in various devices. For example, 1
The present invention is also applicable to a projection display device that projects a monochrome image or a color image using two liquid crystal panels. Further, the present invention can be applied to a display device other than the projection display device.

Also, the projection type display apparatus 1000 has been described as an example in which the illumination optical system of the present invention is applied to a transmission type projection type display apparatus. Can be applied to the projection type display device.
Here, “transmission type” means that the light modulation device is a type that transmits light, and “reflection type” means that the light modulation device is a type that reflects light. ing. Examples of the reflection type light modulation device include a reflection type liquid crystal panel and a digital micromirror device (trademark of TI). In the reflection type projection display device, the cross dichroic prism can be used as a color light separating unit that separates light into three colors of red, green and blue, and recombines the modulated three colors of light into the same light. It can also be used as a color light combining unit that emits light in the direction of. Even when the present invention is applied to a reflection type projection display device, almost the same effects as those of a transmission type projection display device can be obtained.

The present invention is not limited to the above examples and embodiments, but can be implemented in various modes without departing from the gist of the invention.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of an illumination optical system 100 according to a first embodiment as viewed in plan.

FIG. 2 is an explanatory diagram showing a first lens array 40;

FIG. 3 is an explanatory diagram showing a second lens array 50;

FIG. 4 is a front view showing the second lens array 50 and the first lens array 40 from the z-axis direction.

FIG. 5 is a perspective view showing a configuration of a first polarization conversion element array 60a.

FIG. 6 is an explanatory diagram showing functions of a first polarization conversion element array 60a.

FIG. 7 is an explanatory diagram showing a second lens array 50M of a comparative example.

FIG. 8 is an explanatory diagram showing a condensed image formed by the first lens array 40.

FIG. 9 is an explanatory diagram showing a relationship between a converged image formed by a first lens array 40 at a position near a second lens array 50M as a comparative example and the second lens array 50M.

FIG. 10 is a schematic configuration diagram of a main part of an illumination optical system 100A as a second embodiment, as viewed in plan.

FIG. 11 is an explanatory diagram showing a first lens array 40A.

FIG. 12 is an explanatory diagram showing a second lens array 50A.

FIG. 13 is an explanatory diagram showing a second lens array 50N.

FIG. 14 is an explanatory diagram showing a second lens array 50B.

FIG. 15 is a plan view showing an arrangement relationship between a first lens array 40A and a second lens array 50B.

FIG. 16 is an explanatory diagram showing a condensed image formed at a position near a second lens array 50B by a first lens array 40A.

FIG. 17 is an explanatory diagram showing a relationship between a second lens array 50N and a condensed image formed at a position near the second lens array 50A by the first lens array 40.

FIG. 18 shows a second small lens 52N in the second row from the second column of the second lens array 50N and a second small lens 52N in the second row from the second column of the second lens array 50A. It is a schematic side view which shows 2 small lenses 52A.

FIG. 19 is a schematic configuration diagram of a main part of an illumination optical system 100C according to a third embodiment, as viewed in plan.

FIG. 20 is an explanatory diagram showing a first lens array 40C.

FIG. 21 shows a condenser lens 44 of the first lens array 40C.
FIG. 4 is an explanatory diagram showing the function of FIG.

FIG. 22 is a schematic configuration diagram of a main part of a projection display apparatus 1000 using the illumination optical system 100C of the present invention, as viewed in plan.

[Explanation of symbols]

 Reference Signs List 20 light source 22 light source lamp 24 concave mirror 30 split optical system 30A split optical system 30B split optical system 30C split optical system 40 first lens array 40A first lens array 40C first lens Array 40D First lens array 42 First small lens 42A First small lens 42Aa to 42Ac First small lens 42D First small lens 44 Condensing lens 50 Second lens array 50A second lens array 50B second lens array 50C second lens array 50D second lens array 50M second lens array 50N second lens array 52 second small lens 52A .. Second small lens 52B second small lens 52Ba to 52Bc second small lens 52C second small lens 52D second small lens 2M 2nd small lens 52N 2nd small lens 54 ... plane part 54A ... plane part 56 ... substrate part 60 ... polarization conversion optical system 60A ... polarization conversion optical system 60C ... polarization conversion optical system 60a, 60b ... polarization conversion Element array 62 ... Light shielding plate 62a ... Light shielding surface 62b ... Opening surface 64 ... Polarizing beam splitter array 64a ... First light transmitting member 64b ... Second light transmitting member 64c ... Third light transmitting member 66a ... Polarized light Separating film 66b Reflecting film 70 Superimposing optical system 100 Illuminating optical system 100A Illuminating optical system 100C Illuminating optical system 1000 Projection display device 200 Color light separating optical system 202 First dichroic mirror 204 Second Dichroic mirror 208 ... Reflection mirror 220 ... Relay optical system 222 ... Incoming side lens 224,228 ... Reflection mirror 226 ... Relay lens 230: Exit lens (field lens) 232: Field lens 234: Field lens 300R, 300G, 300B: Liquid crystal light valve 320: Cross dichroic prism 321: Red light reflecting dichroic surface 322: Blue light reflecting dichroic surface 340: Projection optical system

Claims (23)

[Claims] An illumination optical system for illuminating a light incident surface of a predetermined optical device as an illumination area, comprising: a light source; and a plurality of small lenses that divide light emitted from the light source into a plurality of partial light beams. A first lens array having a plurality of small lenses respectively corresponding to the plurality of small lenses of the first lens array;
The second lens array is arranged at a position where a plurality of partial light beams emitted from the first lens array are collected, and a plurality of the plurality of small lenses are provided. An illumination optical system in which a planar portion is formed between lens rows. 2. The illumination optical system according to claim 1, wherein the plurality of small lenses of the second lens array are respectively condensed by the corresponding plurality of small lenses of the first lens array. An illumination optical system which is formed in a polygonal shape other than a substantially rectangular shape according to a contour shape of a bundle. 3. The illumination optical system according to claim 1, wherein the plane portion of the second lens array does not have the plane portion, and a plurality of small lenses are spread and arranged. An illumination optical system formed on at least a part of a portion of the plurality of small lenses that causes light to enter the ineffective incident surface of the polarization conversion optical system. 4. The illumination optical system according to claim 2, wherein two light beams which pass through the center of the second lens array and are perpendicular to each other.
When one reference axis is defined, at least a part of the dividing line for dividing the plurality of small lenses of the second lens array has a larger inclination with respect to the two reference axes as the distance from the two reference axes increases. An illumination optical system that is formed as follows. 5. The illumination optical system according to claim 2, wherein at least a part of the plurality of small lenses of the second lens array is one of the two reference lines. An illumination optical system having a trapezoidal shape divided by two division lines parallel to the first and second reference lines and two division lines inclined with respect to the other reference line. 6. The illumination optical system according to claim 1, wherein a light diffusing surface is formed on a surface of the flat portion. 7. The illumination optical system according to claim 1, wherein a light-shielding surface is formed on a surface of the flat portion. 8. The illumination optical system according to claim 1, wherein the first lens array has M columns (M is an integer of 2 or more).
, And the second lens array has N rows (N is an integer of 1 or more smaller than M) of small lens rows, and the second lens array has A plurality of rows of partial light beams formed by a plurality of small lens rows are grouped into a smaller number of rows and incident on the second lens array, thereby being divided by M small lens rows of the first lens array. The illumination optical system, wherein the divided partial light beam is incident on the N small lens rows of the second lens array. 9. The illumination optical system according to claim 8, wherein the plurality of small lens rows in the first lens array are two or more.
A row of small lens rows, wherein the two rows of small lens rows are arranged such that the position of each outer small row of the two row of small lens rows is along the row direction,
One small lens row of the second lens array corresponding to the two small lens rows of the first lens array is arranged so as to be displaced from the position of each small lens of one inner row, A first small lens corresponding to the outer one row of small lenses of the first lens array and a second small lens corresponding to the inner one row of small lenses are alternately arranged; Illumination optics. 10. The illumination optical system according to claim 1, wherein the incident light beam is converted into an exit light beam having a width smaller than the width of the incident light beam. Comprising a system,
Illumination optics. 11. The illumination optical system according to claim 10, further comprising: a condensing lens having a condensing function for realizing the afocal optical system, near the first lens array. The illumination optical system, wherein the plurality of small lenses of the second lens array have a function of collimating light for realizing the afocal optical system. 12. A projection display device for projecting and displaying an image, comprising: an illumination optical system for illuminating a predetermined illumination area; and a light incident surface as the illumination area, wherein A light modulation device that modulates incident light according to image information; and a projection optical system that projects modulated light obtained by the light modulation device. The illumination optical system includes: a light source; and light emitted from the light source. A first lens array having a plurality of small lenses that divides light into a plurality of partial light beams, a second lens array having a plurality of small lenses respectively corresponding to the plurality of small lenses of the first lens array, ,
The second lens array is disposed at a position where a plurality of partial light beams emitted from the first lens array are collected, and the plurality of small lenses are formed by the plurality of small lenses. A projection display device in which a plane portion is formed between lens rows. 13. The projection display according to claim 12, wherein the plurality of small lenses of the second lens array are condensed by the corresponding plurality of small lenses of the first lens array. A projection display device formed in a polygonal shape other than a substantially rectangular shape according to the contour shape of a light beam. 14. The projection type display device according to claim 12, wherein a plurality of small lenses are spread and arranged on the flat portion of the second lens array without the flat portion. A projection display device formed at least in a part of the plurality of small lenses, at which light is incident on the invalid incidence surface of the polarization conversion optical system. 15. The projection display device according to claim 13, wherein two light beams passing through a center of the second lens array and perpendicular to each other are provided.
When one reference axis is defined, at least a part of the dividing line for dividing the plurality of small lenses of the second lens array has a larger inclination with respect to the two reference axes as the distance from the two reference axes increases. A projection display device that is formed as follows. 16. The projection display device according to claim 13, wherein at least a part of the plurality of small lenses of the second lens array is one of the two reference lines. A projection display device having a trapezoidal shape divided by two division lines parallel to a line and two division lines inclined with respect to the other reference line. 17. The projection display device according to claim 12, wherein a light diffusing surface is formed on a surface of the flat portion. 18. The projection display device according to claim 12, wherein a light-shielding surface is formed on a surface of the flat portion. 19. The projection display according to claim 12, wherein the first lens array has M columns (M is an integer of 2 or more).
, And the second lens array has N rows (N is an integer of 1 or more smaller than M) of small lens rows, and the second lens array has A plurality of rows of partial light beams formed by a plurality of small lens rows are grouped into a smaller number of rows and incident on the second lens array, thereby being divided by M small lens rows of the first lens array. A projection display device, wherein the divided partial light beam is configured to be incident on N small lens rows of the second lens array. 20. The projection display device according to claim 19, wherein the plurality of small lens rows in the first lens array has two rows.
A row of small lens rows, wherein the two rows of small lens rows are arranged such that the position of each outer small row of the two row of small lens rows is along the row direction,
One small lens row of the second lens array corresponding to the two small lens rows of the first lens array is arranged so as to be displaced from the position of each small lens of one inner row, A first small lens corresponding to the outer one row of small lenses of the first lens array and a second small lens corresponding to the inner one row of small lenses are alternately arranged; Projection display device. 21. An afocal display according to claim 12, wherein the incident light beam is converted into an outgoing light beam having a width smaller than the width of the incident light beam. Equipped with an optical system,
Projection display device. 22. The projection display device according to claim 21, further comprising: a condensing lens having a condensing function for realizing the afocal optical system, near the first lens array. A projection display device, wherein the plurality of small lenses of the second lens array have a function of collimating light for realizing the afocal optical system. 23. The projection type display device according to claim 12, further comprising: a color light separation optical system for separating light emitted from the illumination optical system into at least two color lights. A plurality of light modulators that respectively modulate the respective color lights separated by the color light separation optical system, and a color light combining optical system that combines modulated lights of respective colors after being modulated by the respective electro-optical devices. A projection display device, wherein the combined light obtained by the color light combining means is projected via the projection optical system.