JP2000250137A - Illuminating optical device and projector device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute an illuminating optical device for a light valve type projector device so that it may occupy a short space in terms of a distance. SOLUTION: The illuminating optical system is provided with a light source 21, a 1st multi-lens array 24 for condensing light emitted from the light source 21, a 2nd multi-lens array 25 on which the light condensed through the 1st multi lens array 24 is made incident, and a light condensing lens 22 for condensing the light from the 2nd multi-lens array 25, and as for the system, a 1st reflection surface 1 for reflecting the light from the light condensing lens 22 and a 2nd reflection surface 2 for reflecting the light from the 1st reflection surface 1 are arranged so that a luminous flux P1 from the light condensing lens 22, a luminous flux P2 from the 1st reflection surface 1 and a luminous flux P3 from the 2nd reflection surface 2 may mutually cross.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating optical device provided with a multi-lens array for making the luminance distribution of light incident on an object uniform. The invention also relates to a projector device provided with such an illumination optical device as an illumination optical system.

[0002]

2. Description of the Related Art Projectors (projection televisions), which are large screen display devices, are broadly classified into CRT projection type and light valve type. FIG. 14 shows a basic configuration example of an optical system of a light valve type projector apparatus. In this projector device, light emitted from a light source 21 such as a discharge lamp is
The light is condensed by 2 and is incident on a spatial light modulator (= light valve) 23 such as a liquid crystal panel. In the spatial light modulator 23, this light is spatially modulated according to the image signal. Then, an image is displayed on the screen 52 by projecting the modulated light onto the screen 52 via the projection optical system 51. In a light valve type projector, an optical system from the light source 21 to a position before the spatial light modulator 23 is usually called an illumination optical system, and this name is used in this specification.

In such a light valve type projector, in order to display an even image on a screen, it is necessary that the luminance distribution of light incident on the spatial light modulator is uniform. However, the brightness of the light of the light source itself often varies depending on the location of the light source. For example, in a discharge lamp often used as a light source, such a variation in luminance occurs due to convection of internal gas and intensity distribution of an electric field between arcs. As a result, when the light emitted from the light source is directly incident on the spatial light modulator through the condenser lens, light having a non-uniform luminance distribution is incident on the spatial light modulator.

Therefore, in general, the illumination optical system of such a projector device is provided with a light integrator, which is an optical element for making the luminance distribution of light incident on the spatial light modulation element uniform. One type of this light integrator is a multi-lens array. As illustrated in FIG. 15, the multi-lens array has a plurality of small (for example, about 1 to 5 mm in diameter) lenses 61 arranged in an array. In the example of this figure, each lens 61 has a shape with both surfaces having a curvature, but one surface of each lens may be flat.

When a multi-lens array is provided in the illumination optical system of the projector shown in FIG. 14, for example, as shown in FIG. 16, two multi-lens arrays 24 and 25 are provided.
To the individual lenses 24 of the multi-lens array 24
a (the lens 61 in FIG. 15) is disposed between the light source 21 and the condenser lens 22 at a distance of about the focal length.

The individual lenses 2 of the multi-lens array 24
The shape of 4a is similar to that of the spatial light modulator 23 so that the light from the lenses is focused on the spatial light modulator 23. On the other hand, the shape of each lens 25a (the lens 61 in FIG. 15) of the multi-lens array 25 does not need to be similar to that of the spatial light modulator 23, and the light from the lens 24a of the multi-lens array 24 is incident as much as possible. What is necessary is just to be the shape which can be made to be made.

In the illumination optical system shown in FIG. 16, the light emitted from the light source 21 is split by each lens 24a of the multi-lens array 24, condensed by the lenses 24a, and opposed to the multi-lens array 25. The light enters the lens 25a. Then, light from each lens 25 a of the multi-lens array 25 is condensed by the condensing lens 22 so as to be superimposed on each other, and is incident on the spatial light modulator 23. As a result, light from all parts of the light source 21 is superimposed and incident on the spatial light modulation element 23, so that the light source 21
Even if the brightness of the light itself varies depending on the region, light having a uniform brightness distribution is incident on the spatial light modulator 23.

FIG. 16 shows an example in which only one condenser lens is provided in the illumination optical system. In this illumination optical system,
The principal ray of the light emitted from the light source 21 is not parallel to the optical axis. That is, this illumination optical system is not a telecentric optical system (an optical system in which a principal ray of light emitted from a light source is parallel to an optical axis).

However, in the light valve type projector, there is a case where at least a part of the illumination optical system is required to be a telecentric optical system. When a telecentric optical system is required in an illumination optical system provided with a multi-lens array, two or more condenser lenses must be provided in the illumination optical system.

FIG. 17 shows an example in which a second condenser lens 26 is added between the condenser lens 22 and the spatial light modulator 23 of the illumination optical system of FIG. In this example, a portion of the illumination optical system behind the condenser lens 26 is a telecentric optical system.

A telecentric optical system is required for the illumination optical system in the following cases. FIG. 16 shows an example in which only one spatial light modulator is used in the illumination optical system. For example, a case where a color projector device is configured using three spatial light modulators corresponding to the three primary colors of RGB will be described. Is an optical element (color separation mirror or color separation prism) that separates white light emitted from a light source into three primary colors of RGB.
And an optical element (color combining prism) for combining the light of the three primary colors from each spatial light modulator must be provided in the illumination optical system.

As shown in FIG. 18, an illumination optical system which is not a telecentric optical system (for example, a portion before the condenser lens 26 in FIG. 17 is shown) has such an optical system for color separation or color synthesis. When the element 71 is provided, the angle of incidence of light on the optical element 71 differs depending on the position of the optical element 71.

However, in the case of a metal thin film or the like coated on an optical element for color separation or color synthesis, FIGS. 19A and 19B show the relationship between the incident angle of the long wavelength reflection color separation mirror 72 and the short wavelength reflection color separation mirror 73, respectively. As exemplified by the wavelength characteristics, the relationship between the wavelength and the reflectance changes according to the incident angle. As a result, when an optical element for color separation or color synthesis is provided in an illumination optical system that is not a telecentric optical system, light separated by the optical element for color separation and incident on the spatial light modulator, or light for color synthesis Color unevenness occurs in light combined by the optical element.

On the other hand, as shown in FIG. 20, a portion of the illumination optical system which is a telecentric optical system (for example, a portion behind the condenser lens 26 in FIG. 17) is used for color separation or color separation. When the optical element 71 for synthesis is provided,
Since the angle of incidence of light on the optical element 71 is constant irrespective of the position of the optical element 71, the occurrence of color unevenness is prevented. For these reasons, when configuring a color projector device, a telecentric optical system is required for the illumination optical system.

FIG. 16 shows an illumination optical system using a transmissive spatial light modulator. For example, even in a monochrome projector, when a reflective spatial light modulator is used, a spatial light modulator is used. A polarizing beam splitter must be provided in the illumination optical system to make the direction of light incident on the element different from that of light reflected from the spatial light modulator. And
Even in a thin film or the like coated on the reflection surface of the polarization beam splitter, the relationship between the wavelength and the reflectance changes according to the incident angle, as shown in FIG. Therefore, even when a reflective spatial light modulator is used, a telecentric optical system is required for the illumination optical system.

[0016]

In a conventional light valve type projector, an illumination optical system provided with a multi-lens array occupies a long space regardless of whether it is a telecentric optical system or not. I was

That is, in an illumination optical system other than the telecentric optical system as shown in FIG.
The distance from to the spatial light modulator 23 becomes longer. The reason is as follows. In this illumination optical system, the images of the individual lenses 24a of the multi-lens array 24 are
Thereby, an image is formed on the spatial light modulator 23. Here, from the theory of the imaging optical system, as shown in FIG.
The size ratio between the object y1 and the image y2 is equal to the ratio between the distance h1 from the object y1 to the lens Le and the distance h2 from the lens Le to the image.

In the illumination optical system shown in FIG. 16, the image of each lens 24a of the multi-lens array 24 is changed to the object y1 shown in FIG.
21; the distance from the lens 24a to the condenser lens 22 corresponds to the distance h1 in FIG. 21; the image of the lens 24a formed on the spatial light modulator 23 corresponds to the image y2 in FIG.
The distance from the condenser lens 22 to the spatial light modulator 23 corresponds to h2 in FIG. Since the lens 24a is generally much smaller than the spatial light modulator 23, the distance from the condenser lens 22 to the spatial light modulator 23
This is considerably longer than the distance from 4a to the condenser lens 22.

Further, in the illumination optical system including the telecentric optical system as shown in FIG. 17, the distance from the condenser lens 22 to the spatial light modulator 23 becomes longer for the same reason. In addition, in the illumination optical system of FIG. 17, since the two condenser lenses 22 and 26 are present, the distance from the lens 24a to the position between the condenser lens 22 and the condenser lens 26 is h1 in FIG. (That is, h1 is longer than in the illumination optical system of FIG. 16), so that the distance from the condenser lens 22 to the spatial light modulator 23 is correspondingly longer.

Further, in an illumination optical system including a telecentric optical system, since a color separation optical element and a polarizing beam splitter are provided at a portion behind the converging lens 26 which is a telecentric optical system, spatial light is transmitted from the converging lens 26. The distance to the modulation element 23 must be increased. As a result, the distance from the condenser lens 22 to the spatial light modulator 23 becomes longer than that shown in FIG.

In particular, in a color projector provided with three transmissive spatial light modulators corresponding to the three primary colors of RGB, among the illumination optical system including the telecentric optical system, the light is collected from the condenser lens 22. The length of the distance to the optical lens 26 becomes noticeable.

FIG. 22 shows an example of the configuration of a conventional illumination optical system of such a color projector device. In this illumination optical system, a portion behind the condenser lens 26, which is a telecentric optical system, is provided with color separation mirrors 71 and 72.
Reflection mirrors 73 to 75 and a relay lens 76 for guiding the light separated by the color separation mirrors 71 and 72 to three transmission-type spatial light modulators 27, 28, and 29; A color synthesizing prism 77 for synthesizing light of the three primary colors transmitted through 29 is provided.

On the other hand, the portion of the illumination optical system from the condenser lens 22 to the condenser lens 26 is not only used for a long distance but is not used for providing any optical element. Therefore, the length of the distance from the condenser lens 22 to the condenser lens 26 is particularly noticeable.

In order to effectively use the portion from the condenser lens 22 to the condenser lens 26, there has conventionally been a color projector device provided with a color separation mirror or the like in this portion. However, since this portion is not a telecentric optical system, as described above with reference to FIGS. 18 and 19, color unevenness occurs in the color projector device. Therefore, in order to prevent the occurrence of such color unevenness, a color separation mirror or the like must be disposed in a portion behind the condenser lens 26 as well.

As described above, in the conventional light valve type projector, the illumination optical system provided with the multi-lens array occupies a long distance space in order to make the luminance distribution of light uniform. There has been a disadvantage that the entire apparatus becomes large.

In the above, the illumination optical system of the projector device has been described as an example of the related art. However, it is necessary to make the luminance distribution of the light incident on the object uniform even in the optical system of a device other than the projector device. (For example, an optical system of an exposure apparatus which is an apparatus for transferring a pattern of a semiconductor element or a wiring formed on a mask to a photosensitive resin on a wafer). Even in such an optical system, there is a disadvantage that providing a multi-lens array also occupies a long space.

Accordingly, an object of the present invention is to make an optical system having a multi-lens array occupy a shorter space than a conventional one in order to make the luminance distribution of light incident on an object uniform. It is in. In the present specification, an optical system that makes light incident on an object as in an illumination optical system of a light valve type projector device is referred to as
It is generically called an illumination optical device.

[0028]

In order to solve this problem, the present applicant collects a light source, such as an illumination optical system in a light valve type projector, and collects light emitted from the light source. A first multi-lens array, a second multi-lens array on which light condensed by the first multi-lens array is incident, and a condensing light for condensing light from the second multi-lens array An illumination optical device having a lens and a first reflection surface for reflecting light from the condenser lens, as described in claim 1, and the first reflection surface.
And a second reflecting surface for reflecting light from the reflecting surface such that the light beam from the condenser lens, the light beam from the first reflecting surface, and the light beam from the second reflecting surface cross each other. We propose an illumination optical device with a simple arrangement.

In this illumination optical device, the light beam from the condenser lens is such that the light beam from the condenser lens, the light beam from the first reflecting surface and the light beam from the second reflecting surface intersect each other. As a result, the light is reflected by the first reflection surface and the second reflection surface. Thereby, the light from the condenser lens is focused on the first reflection surface and the second reflection surface before being converged and incident on the object.
Is reflected by the reflection surface of the lens and passes through the same place three times. Therefore, the distance from the condenser lens to the object is significantly shorter than before, so that the illumination optical device occupies a space that is much shorter than before.

In this illumination optical device, as an example, the first reflection surface and the second reflection surface may be arranged so as to form an angle of 45 degrees with each other. It is suitable. Thus, the direction of the light emitted from the light source changes exactly 90 degrees by being reflected by the first reflection surface and the second reflection surface.

Therefore, if this illumination optical device is applied to an optical system including a light source which must be arranged in a direction in which light is emitted in a horizontal direction, for example, light is emitted while the light source is arranged in such a direction. It is possible to bend in the vertical direction (therefore, the optical element after the second reflecting surface is arranged in the vertical direction).

In this illumination optical device, as an example, it is preferable that the first reflecting surface and the second reflecting surface are formed by the same prism surface. . As a result, the first reflection surface and the second reflection surface are constituted by one optical element, so that the number of optical elements that need to be added to the conventional illumination optical device can be reduced, and Adjustment (for example, adjusting the angle formed between the first reflecting surface and the second reflecting surface to a constant angle) is facilitated.

Next, the present applicant discloses a light source and a first light source for condensing light emitted from the light source.
A multi-lens array, a second multi-lens array on which light condensed by the first multi-lens array is incident, and a first reflecting surface for reflecting light from the second multi-lens array. , A second reflecting surface for reflecting light from the first reflecting surface, and the first and second reflecting surfaces are configured to be coupled with the light beam from the second multi-lens array and the first reflecting surface. And a light beam from the second reflecting surface is arranged to intersect with each other, and at least one of the first reflecting surface and the second reflecting surface is concave. An optical device is proposed.

In this illumination optical device, the light beam from the second multi-lens array is divided into the light beam from the second multi-lens array, the light beam from the first reflecting surface, and the light beam from the second reflecting surface. So that the light beams intersect each other,
And the second reflection surface. This allows
By the time the light from the second multi-lens array is incident on the object, the light is reflected by the first reflection surface and the second reflection surface and passes through the same place three times.

Further, in this illumination optical device, since at least one of the first reflecting surface and the second reflecting surface is concave, light from the second multi-lens array is reflected by these reflecting surfaces. The light is condensed (that is, these reflection surfaces also function as condensing lenses).

Therefore, at least a part of the condensing lens provided in the conventional illumination optical device becomes unnecessary, and the distance from the second multi-lens array to the object becomes significantly shorter than before. This allows the illumination optics to occupy a shorter distance of space and reduces the number of optical elements of the illumination optics.

In this illumination optical device, as an example, the first reflecting surface and the second
It is preferable that the reflecting surface of the lens is formed of the same prism surface, so that the number of optical elements that need to be added to the conventional illumination optical device can be reduced, and the optical adjustment can be performed. It will be easier.

Next, the present applicant discloses a light source and a first light source for condensing light emitted from the light source.
A multi-lens array, a second multi-lens array to which light condensed by the first multi-lens array is incident, and a condensing lens for condensing light from the second multi-lens array; A first reflection surface for reflecting light from the condenser lens, a second reflection surface for reflecting light from the first reflection surface, and light condensed by the condenser lens, A spatial light modulator that modulates the light in accordance with an image signal; a projection optical system on which light modulated by the spatial light modulator is incident; and a screen on which light from the projection optical system is projected. , The first reflection surface and the second reflection surface are arranged such that the light beam from the condenser lens, the light beam from the first reflection surface, and the light beam from the second reflection surface cross each other. We propose a light valve type projector.

In this projector device, the light from the condenser lens of the illumination optical system is reflected by the first reflection surface and the second reflection surface before being collected and incident on the spatial light modulator. Pass the same place three times. Therefore, the distance from the condenser lens to the spatial light modulator is significantly shorter than before, so that the illumination optical system occupies only a much shorter space than before. It is downsized.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to an illumination optical system of a light valve type projector will be described below. FIG. 1 is a diagram showing an example of a basic configuration of an illumination optical system of a light valve type projector device to which the present invention is applied. The same parts as those in FIG. Omitted.

The illumination optical system of this projector device includes:
The reflection mirror 1 that reflects the light from the condenser lens 22 and the reflection mirror 2 that reflects the light from the reflection mirror 1 are reflected by the ray bundle P1 from the condenser lens 22 and the ray bundle P2 from the reflection mirror 1. The light beam bundle P3 from the mirror 2 is provided so as to intersect each other. Then, light from the reflection mirror 2 is transmitted to a spatial light modulator (for example, a liquid crystal panel) 2.
3 is incident.

Thus, in this illumination optical system, the light from the condenser lens 22 is reflected by the reflection mirror 1 and the reflection mirror 2 before being converged and incident on the spatial light modulator 23, and is reflected at the same position. (A place surrounded by the condenser lens 22, the reflection mirror 1, and the reflection mirror 2) three times.

FIG. 2 shows an example of the arrangement angles and intervals of the reflection mirrors 1 and 2 in detail. Optical axis a of an optical element from a light source (for example, a discharge lamp) 21 to a condenser lens 22
Assuming that the direction of x is the X-axis direction and the direction orthogonal to the X-axis direction in the drawing is the Y-axis direction, the reflection mirror 1 sets the normal of the reflection surface to θ1 = 22 with respect to the X-axis in the XY plane. .5 degrees. In the reflection mirror 1, the interval t1 between the center of the condenser lens 22 and the center c1 of the reflection mirror 1 (referred to as a point on the optical axis ax) is (1 + 2) / 2 times the diameter h of the condenser lens 22 ( (About 1.207 times).

The reflection mirror 2 sets the normal of the reflection surface to X.
It is arranged at an angle θ2 = 22.5 degrees with respect to the Y axis in the Y plane. Thereby, the reflection surface of the reflection mirror 1 and the reflection surface of the reflection mirror 2 form an angle of 45 degrees with each other. The reflection mirror 2 has a center c1 of the reflection mirror 1 and a center c2 of the reflection mirror 2 (light on the optical axis ax is not reflected by the reflection mirror 1).
(Which is a point where the light is reflected and enters the reflection mirror 2) is arranged so that the distance t2 is approximately the same as the diameter h of the condenser lens 22.

FIG. 3 shows the change in the direction of light by the reflection mirrors 1 and 2. Optical axis ax emitted from light source 21
The direction of the upper light is changed by 45 degrees in the Y-axis direction in the XY plane by the reflection mirror 1, and further changed by 45 degrees in the Y-axis direction in the XY plane by the reflection mirror 2, so that the Y direction is just Y from the X-axis direction. Bend in the axial direction (ie a total of 9
0 degree).

The light emitted from the light source 21 is condensed by the condensing lens 22. Even if the direction of the light from the periphery of the condensing lens 22 is assumed to be parallel to the optical axis ax, 2, the light L1 and L2 from the peripheral edge are obstructed by the reflection mirrors 1 and 2 and the condenser lens 22, as shown in FIG. Never. That is, the light from the condenser lens 22 is not obstructed at all by the reflection mirrors 1 and 2 and the condenser lens 22 before being converged and incident on the spatial light modulator 23. Therefore, the loss of the amount of light incident on the spatial light modulation element 23 hardly occurs (there is only a slight loss because only a small part of the incident light is not reflected by the reflection mirrors 1 and 2).

FIG. 4 shows the space occupied by the illumination optical system of FIG. 1 and the space occupied by the conventional illumination optical system as shown in FIG.
4A and FIG. 4B when the optical path length is the same (approximately 3.414 times h). In the illumination optical system of FIG. 1, the same place is set to three times until the light from the condenser lens 22 enters the spatial light modulator 23.
Therefore, the distance from the condensing lens 22 to the spatial light modulator 23 is significantly shorter than that of the conventional illumination optical system. As a result, the illumination optical system has a considerably shorter distance than the conventional illumination optical system. Only occupy.

The illumination optical system shown in FIG. 1 can be realized at low cost because the optical element can be constituted by adding only two reflecting mirrors to the conventional illumination optical system.

Some types of light sources included in the illumination optical system of the projector device must be arranged in such a direction that light is emitted in a horizontal direction when used. Therefore, for example, in the case where the light source 21 in FIG. 1 is such a light source, if the direction of the optical axis ax (X-axis direction) shown in FIG. With the light source 21 installed in such a direction that
The direction of light in the illumination optical system is set to 9 by the reflection mirrors 1 and 2.
The optical element can be changed by 0 degree to make it vertical (therefore, the optical element after the reflection mirror 22 is arranged in the vertical direction).

Next, FIGS. 5 to 7 show specific examples of the configuration of the illumination optical system of FIG. 1 in various light valve type projectors. Among them, FIG.
This is an example of an illumination optical system of a monochrome projector device using only one transmissive spatial light modulation element in the same manner as described above. Light from the condenser lens 22 is reflected by the reflection mirrors 1 and 2 respectively, and After three passes, the spatial light modulator 23
Is incident on. The light transmitted through the spatial light modulator 23 (light modulated according to the image signal) is projected on a screen (not shown) via the projection optical system 51.

In the projector device of FIG. 5, FIG.
As is clear from the comparison with the projector device, since the distance from the condenser lens 21 to the spatial light modulator 23 is significantly reduced, the illumination optical system occupies only a relatively short distance. In addition, the entire device is smaller than before.

As described above, the reflection mirrors 1 and 2
Changes the direction of light by 90 degrees in the illumination optical system while keeping the light source 21 installed in such a direction that the direction of the emitted light is horizontal. (The same applies to the projector device shown in FIGS. 6 and 7 described later).

FIG. 6 shows an example of an illumination optical system of a monochrome projector using only one reflection-type spatial light modulator. As already described with reference to FIGS.
When a reflection type spatial light modulator is used, a telecentric optical system is required for the illumination optical system. Therefore, the illumination optical system of this projector device includes a condenser lens 22 and a reflection type spatial light as in FIG. A second condensing lens 26 is provided between the modulator 30 and the modulator 30.

The reflection mirrors 1 and 2 shown in FIG. 1 are provided between the condenser lens 22 and the condenser lens 26. Therefore, the light from the condenser lens 22 is reflected by the reflection mirrors 1 and 2 respectively, passes through the same place three times, and then enters the condenser lens 26.

If the direction of the light incident on the spatial light modulator 30 from the condenser lens 26 and the direction of the reflected light from the spatial light modulator 30 are different from each other in a portion behind the condenser lens 26 which is a telecentric optical system. A polarizing beam splitter 41 is provided.

The light from the condenser lens 26 passes through the polarization beam splitter 41 and enters the spatial light modulator 30. Then, the light reflected by the spatial light modulator 30 (light modulated in accordance with the image signal) is reflected by the polarization beam splitter 41 and then projected on a screen (not shown) via the projection optical system 51. You.

In the projector device shown in FIG. 6, the distance from the condenser lens 22 to the condenser lens 26 is significantly shorter than that in the related art (therefore, the distance from the condenser lens 22 to the spatial light modulator 30 is smaller). Since the illumination optical system occupies a space that is considerably shorter than before, the entire apparatus is smaller than before.

FIG. 7 shows an example of an illumination optical system of a color projector using three reflective spatial light modulators corresponding to the three primary colors of RGB. As already described with reference to FIGS. 18 to 20, since a telecentric optical system is required for the illumination optical system even when a color projector device is configured, the illumination optical system of this projector device also includes:
Condensing lens 22 and reflective spatial light modulators 31 and 32
And 33, a second condenser lens 26 is provided.

The reflection mirrors 1 and 2 shown in FIG. 1 are provided between the condenser lens 22 and the condenser lens 26. Therefore, the light from the condenser lens 22 is reflected by the reflection mirrors 1 and 2 respectively, passes through the same place three times, and then enters the condenser lens 26.

Further, at a portion behind the converging lens 26 which is a telecentric optical system, the light from the converging lens 26 is separated into light of three primary colors and each of the spatial light modulators 31 and 3 is provided.
Color separation for combining reflected light of three primary colors from 2 and 33
A combining prism 42 and a polarizing beam splitter 43 for changing the direction of light incident on these spatial light modulators and the direction of light reflected from these spatial light modulators are provided.

The light from the condenser lens 26 passes through the polarization beam splitter 43 and is separated from the color separation / combination prism 42.
Are separated into light of three primary colors and the corresponding spatial light modulator 3
1, 32 and 33. Then, reflected lights of three primary colors (light modulated according to RGB image signals) from the spatial light modulators 31, 32 and 33 are combined by a color separation / combination prism 42 and reflected by a polarization beam splitter 43. After that, the image is projected on a screen (not shown) via the projection optical system 51.

In the projector of FIG. 7 as well, the distance from the condenser lens 22 to the condenser lens 26 is significantly shorter than in the prior art (therefore, the distance from the condenser lens 22 to the spatial light modulators 31, 32 and 33) is reduced. Since the distance of the part is significantly shorter than before, the illumination optical system occupies only a space of a considerably shorter distance than before, so that the whole apparatus is smaller than before.

FIG. 7 shows a color projector device using a reflection type spatial light modulator, but FIG. 7 shows a color projector device using a transmission type spatial light modulator as shown in FIG. (For example, even if the reflection mirrors 1 and 2 are provided between the condenser lens 22 and the condenser lens 26 in FIG. 2), it is of course that the entire apparatus can be made smaller than before. It is.

In the projector shown in FIG. 6 or 7, instead of providing the reflection mirrors 1 and 2 between the condenser lens 22 and the condenser lens 26, the multi-lens array 25 and the condenser lens 22 The reflection mirrors 1 and 2 may be provided between them.

Next, FIGS. 8 and 9 show modifications of the arrangement angles of the reflection mirrors 1 and 2 of the illumination optical system of FIG. 1 (modifications to the example of FIG. 2). Among them, in the example of FIG. 8, the reflection mirror 1 sets the normal of the reflection surface to X.
The reflection mirror 2 is disposed at a tilt of θ3 = 21.75 degrees with respect to the X axis in the Y plane, and the reflection mirror 2 tilts the normal of the reflection surface by θ4 = 24.75 degrees with respect to the Y axis in the XY plane. Are located. Since the reflection surface of the reflection mirror 1 and the reflection surface of the reflection mirror 2 form an angle of 43.5 degrees with each other, the direction of light on the optical axis ax emitted from the light source 21 is reflected. 43. In the Y-axis direction in the XY plane by the mirror 1
5 degrees, and further reflected by the reflection mirror 2 in the XY plane.
A change of 43.5 degrees in the axial direction results in a total change of 87 degrees.

In the example of FIG. 9, the reflecting mirror 1 sets the normal of the reflecting surface to θ5 = 23.2 with respect to the X axis in the XY plane.
The reflection mirror 2 is arranged at an angle of θ5 = 20.25 degrees with respect to the Y axis in the XY plane in the XY plane. Accordingly, the reflection surface of the reflection mirror 1 and the reflection surface of the reflection mirror 2 form an angle of 46.5 degrees with each other, so that the optical axis ax emitted from the light source 21 is formed.
The direction of the upper light is changed by 46.5 degrees in the Y-axis direction in the XY plane by the reflection mirror 1, and further changed by 46.5 degrees in the Y-axis direction in the XY plane by the reflection mirror 2.
It changes 93 degrees in total.

In the projector device using the reflection type spatial light modulator as shown in FIGS. 6 and 7, whether the angle of the arrangement of the reflection mirrors 1 and 2 is the same as in the example of FIG. It is preferable to determine whether to use the configuration shown in FIG. 9 according to, for example, the type of a polarizing beam splitter provided in the illumination optical system.

That is, the polarization beam splitter is the one shown in FIG.
As shown by a polarization beam splitter 44 at 0, a type in which the incident angle of light on the polarization splitting surface is 45 degrees is widely used. This is because the incident angle of light to the polarization splitting surface of 45 degrees is convenient when using a polarizing beam splitter.

As is well known, the polarization beam splitter has a reflectance and a transmittance for an object made of the same material for P-polarized light (electric field component parallel to the incident surface) and S-polarized light (electric field component perpendicular to the incident surface). Is different, and by transmitting P-polarized light and reflecting S-polarized light on the polarization separation surface, P
The polarized light and the S-polarized light are separated from each other. Each material has an angle at which the reflectance of P-polarized light becomes zero (referred to as Brewster angle). When the angle of incidence of light on the polarization splitting surface is matched with this Brewster angle, the P-polarized light And S-polarized light have the best separation accuracy.

Glass having a refractive index of about 1.5 to 1.9 is generally used as a material of the polarizing beam splitter.
The Brewster angle of this glass is not 45 degrees. Therefore, in the polarization beam splitter of the type in which the incident angle is 45 degrees as shown in FIG. 10, in order to improve the separation accuracy, a multi-layered beam splitter designed so that the separation accuracy is the best when the incident angle is 45 degrees. A thin film is coated on the polarization splitting surface.

On the other hand, if a polarizing beam splitter of a type whose incident angle is closer to the Brewster angle of glass than 45 degrees is manufactured, the design of a multilayer thin film coated on the polarization splitting surface becomes very simple. 45 incident angle
Separation accuracy can be further improved as compared with a polarization beam splitter of a certain type. Therefore, if such a polarizing beam splitter is provided in a projector device using a reflective spatial light modulator, the contrast can be improved.

FIG. 11 shows an example of such a type of polarizing beam splitter, in which the angle of incidence of light on the polarization splitting surface is 48 degrees and the angle of incidence of light on the polarization separating surface is 42 degrees. And the polarization beam splitter 46 shown in FIG. Among them, a polarization beam splitter such as the polarization beam splitter 45 having an incident angle of 48 degrees is already widely used. Thus, in addition to the type of the polarizing beam splitter, the incident angle is 45 degrees,
Some have an incident angle of 48 degrees, and others have an incident angle of 42 degrees.

Therefore, in a projector device using a reflection type spatial light modulator as shown in FIGS.
As shown in the polarization beam splitter 44 in FIG.
In the case where a polarization beam splitter of a type having an angle of 5 degrees is provided in the illumination optical system, the angle of the arrangement of the reflection mirrors 1 and 2 is set as shown in FIG. It is preferable that the light be changed in the direction by 90 degrees so as to be incident on the polarizing beam splitter. Accordingly, the direction of light reflected by the polarization splitting surface of the polarization beam splitter and incident on the projection optical system can be made parallel to the direction of light emitted from the light source.

Further, in a projector apparatus using a reflection type spatial light modulator as shown in FIGS. 6 and 7, the incident angle is 48 as in the polarization beam splitter 45 in FIG.
In the case where a polarization beam splitter of a different type is provided in the illumination optical system, the angle of the arrangement of the reflection mirrors 1 and 2 is set as in the example of FIG. It is preferable that the emitted light on the optical axis ax be changed in direction by 93 degrees so as to be incident on the polarization beam splitter. Thereby, the direction of the light (S-polarized light) reflected by the polarization splitting surface of the polarization beam splitter becomes coincident with the direction of the optical axis ax, so that the direction of the light entering the projection optical system is also emitted from the light source. Parallel to the direction of the light to be emitted.

In a projector device using a reflection type spatial light modulator as shown in FIGS. 6 and 7, an incident angle of 42 is used as in a polarization beam splitter 46 in FIG.
In the case where a polarization beam splitter of a different type is provided in the illumination optical system, the angle of the arrangement of the reflection mirrors 1 and 2 is set as in the example of FIG. It is preferable that the emitted light on the optical axis ax be changed in the direction of 87 degrees so as to be incident on the polarization beam splitter. As a result, the direction of the light reflected by the polarization splitting surface of the polarization beam splitter is changed to the optical axis a.
Since the direction coincides with the direction of x, the direction of light incident on the projection optical system can be made parallel to the direction of light emitted from the light source.

Next, FIG. 12 shows a modification of the optical element that reflects the light from the condenser lens 22 in the illumination optical system of FIG. This illumination optical system is provided with a prism 3 instead of the reflection mirrors 1 and 2 in FIG.
The prism 3 separates the reflecting surface 3a that reflects light from the condenser lens 22 and the reflecting surface 3b that reflects light from the reflecting surface 3a from the light beam P1 from the condenser lens 22 and the reflecting surface 3a. And the light beam P5 from the reflection surface 3b are arranged so as to intersect each other. The reflecting surfaces 3a and 3b are formed by coating the surface of the prism 3 with a thin film or the like that reflects visible light and transmits infrared light and ultraviolet light.

Thus, even in this illumination optical system, the light from the condenser lens 22 is reflected by the reflection surfaces 3a and 3b and is reflected at the same position before being condensed and incident on the spatial light modulator 23. (Condenser lens 22, reflection surface 3a and reflection surface 3
b) three times.

The interval between the arrangement of the reflecting surfaces 3a and 3b is
The intervals between the reflection mirrors 1 and 2 in FIG. 1 may be the same as those described with reference to FIG. Also, the angle of arrangement of the reflecting surfaces 3a and 3b may be the same as any of the angles described with reference to FIGS. 2, 8 and 9 for the reflecting mirrors 1 and 2.

Also in the illumination optical system shown in FIG. 12, the light from the condenser lens 22 passes through the same place three times before being incident on the spatial light modulator 23. Again, the distance from the condenser lens 22 to the spatial light modulator 23 is significantly shorter, and as a result, the illumination optical system occupies a much shorter space than before.

Further, the illumination optical system of FIG. 12 can be constituted by adding only one prism to the conventional illumination optical system as an optical element, so that the number of optical elements can be reduced. Optical adjustment (for example, reflecting surface 3a
(Adjusting the angle formed by the reflection surface 3b to 45 degrees, 43.5 degrees, or 46.5 degrees).

FIG. 13 is a diagram showing another example of the basic configuration of the illumination optical system of the light valve type projector device to which the present invention is applied. The same parts as those in FIG. The reference numerals are given and the duplicated explanation is omitted.

In this illumination optical system, a condenser lens as in the illumination optical system of FIG. 1 is not provided, and a reflecting mirror 11 for reflecting light from the multi-lens array 25 is provided.
The reflection mirror 12 that reflects the light from the reflection mirror 11 is arranged such that the light beam P6 from the multi-lens array 25, the light beam P7 from the reflection mirror 11, and the light beam P8 from the reflection mirror 12 intersect each other. It is equipped with. The reflecting surfaces of the reflecting mirrors 11 and 12 are not flat like the reflecting mirrors 1 and 2 in FIG. 1 but are concave surfaces. Then, light from the reflection mirror 12 is incident on the spatial light modulator 23.

Thus, in this illumination optical system, the light from the multi-lens array 25 is reflected by the reflection mirror 11 and the reflection mirror 12 and is surrounded by the same place (the multi-lens array 25, the reflection mirror 11, and the reflection mirror 12 are surrounded). Three times).

Further, in this illumination optical system, since the reflecting surfaces of the reflecting mirrors 11 and 12 are concave, the light from the multi-lens array 25 is condensed by these reflecting surfaces (that is, these reflecting surfaces). Also function as a condenser lens).

In the illumination optical system shown in FIG. 13, a condenser lens corresponding to the condenser lens 22 of the illumination optical system shown in FIG. 1 is not provided, and the distance from the multi-lens array 25 to the spatial light modulator 23 is reduced. It is significantly shorter than before.
As a result, the space occupies a shorter distance than the illumination optical system of FIG. 1, and the number of optical elements is reduced compared to the illumination optical system of FIG.

The arrangement angles of the reflection mirrors 11 and 12 in the illumination optical system of FIG. 13 are the same as those described with reference to FIGS. 2, 8 and 9 for the reflection mirrors 1 and 2 of FIG. May be. Although the illumination optical system shown in FIG. 13 does not include a condenser lens, the location of the reflection mirrors 11 and 12 in the entire illumination optical system depends on the interval between the locations described with reference to FIG. The location of the reflection mirrors 1 and 2 in the entire illumination optical system of FIG. 1 to be determined may be the same.

The illumination optical system shown in FIG. 13 is also provided in a monochrome projector or a color projector using a reflective or transmissive spatial light modulator.
It goes without saying that the entire projector apparatus can be downsized in the same manner as described with reference to FIGS. 5 to 7 for the illumination optical system of FIG.

Also, in the illumination optical system of FIG. 13, similarly to the illumination optical system of FIG. 1, a prism (a reflection surface is concave) is used instead of the reflection mirrors 11 and 12, as shown in FIG. Accordingly, a portion where the reflection surface is formed is convex when viewed from the outside).

In the example of FIG. 13, the reflecting surfaces of the reflecting mirrors 11 and 12 are both concave, but only one of the reflecting surfaces of the reflecting mirrors 11 and 12 is concave, and the other one is concave. It may be flat. Also, when a prism is provided instead of the reflection mirrors 11 and 12, only one of the two reflection surfaces may be concave and the other may be flat. Even in such a case, these reflecting surfaces can also function as a condenser lens.

In the above example, the direction of the light emitted from the light source is adjusted to 90 degrees, 87 degrees by a reflecting mirror or a prism.
Although the angle is changed by any one of degrees and 93 degrees, the direction of the light may be changed by any other appropriate angle.

In the above example, the present invention is applied to the illumination optical system of the light valve type projector.
For example, the present invention may be applied to an optical system of an appropriate device other than a projector device provided with a multi-lens array in order to make the luminance distribution of light incident on an object uniform, such as an optical system of an exposure apparatus. . Further, the present invention is not limited to the above-described example, and it is needless to say that various other configurations can be adopted without departing from the gist of the present invention.

[0092]

As described above, according to the illumination optical device of the first aspect of the present invention, the light from the condenser lens is
The light is reflected by the first reflection surface and the second reflection surface and passes through the same place three times. As a result, the distance from the condenser lens to the object becomes significantly shorter than in the past, so that the effect that the illumination optical device can occupy a space much shorter than in the past can be obtained.

In this illumination optical device, when the first reflecting surface and the second reflecting surface are arranged so as to form an angle of 45 degrees with each other, the light from the light source may The direction of the emitted light can be changed exactly 90 degrees by the first reflection surface and the second reflection surface. Therefore, if this illumination optical device is applied to an optical system that includes a light source that must be arranged in a direction such that the direction of emitted light is horizontal, for example, the light is emitted while the light source is arranged in such a direction. The effect that the optical element can be bent in the vertical direction (therefore, the optical element after the second reflecting surface is disposed in the vertical direction) can be additionally obtained.

In the illumination optical device, when the first reflecting surface and the second reflecting surface are formed of the same prism surface, one optical element is provided. Since the first reflection surface and the second reflection surface are configured by the above, the number of optical elements that need to be added to the conventional illumination optical device can be reduced, and the optical adjustment (for example, the first reflection surface) can be performed. (Adjusting the angle between the reflecting surface and the second reflecting surface to a constant angle) is also easily obtained.

Next, according to the illumination optical device of the fourth aspect of the present invention, the light from the second multi-lens array is reflected by the first reflection surface and the second reflection surface and becomes the same. Light passes through the location three times and from the second multi-lens array is collected by these reflective surfaces (ie, these reflective surfaces also serve as condensing lenses).

Therefore, at least a part of the condensing lens provided in the conventional illumination optical device becomes unnecessary, and the distance from the second multi-lens array to the object becomes significantly shorter than in the prior art. The effect is obtained that the optical device can occupy a shorter space, and the number of optical elements of the illumination optical device can be reduced.

In this illumination optical device, when the first reflecting surface and the second reflecting surface are formed of the same prism surface as in the fifth aspect, the conventional optical system is still used. The effect of reducing the number of optical elements that need to be added to the illumination optical device and the effect of facilitating optical adjustment are also obtained.

Next, according to the projector device of the sixth aspect of the present invention, the distance from the condenser lens to the spatial light modulator is significantly shorter than before, so that the illumination optical system becomes more compact than before. Since the space occupies only a considerably short space, an effect is obtained that the whole projector device can be made smaller than before.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a basic configuration of an illumination optical system of a light valve type projector device to which the present invention is applied.

FIG. 2 is a diagram showing an example of the arrangement angles and intervals of the reflection mirror of FIG. 1;

FIG. 3 is a diagram showing a change in the direction of light by the reflection mirror of FIG. 1;

FIG. 4 is a diagram showing a space occupied by the illumination optical system of FIG. 1 in comparison with a space occupied by a conventional illumination optical system.

FIG. 5 is a diagram showing a specific configuration example of the illumination optical system of FIG. 1 in the monochrome projector device.

FIG. 6 is a diagram showing a specific configuration example of the illumination optical system of FIG. 1 in the monochrome projector device.

FIG. 7 is a diagram showing a specific configuration example of the illumination optical system of FIG. 1 in the color projector device.

FIG. 8 is a diagram showing an example of changing the angle of arrangement of the reflection mirror in FIG. 1;

FIG. 9 is a diagram showing an example of changing the arrangement angle of the reflection mirror in FIG. 1;

FIG. 10 is a diagram illustrating an example of a polarization beam splitter and its incident angle on a polarization splitting surface.

FIG. 11 is a diagram illustrating an example of a polarization beam splitter and an angle of incidence on a polarization splitting surface thereof.

FIG. 12 is a diagram illustrating a modification of the optical element that reflects light from the condenser lens in the illumination optical system of FIG. 1;

FIG. 13 is a diagram showing another example of the basic configuration of the illumination optical system of the light valve type projector device to which the present invention is applied.

FIG. 14 is a diagram illustrating a basic configuration example of an optical system of a light valve type projector device.

FIG. 15 is a diagram showing an example of a multi-lens array from the front, top, and side.

FIG. 16 is a diagram showing an example in which a multi-lens array is provided in the illumination optical system of the projector device of FIG.

17 is a diagram illustrating an example in which a second condenser lens is provided in the illumination optical system of FIG. 16;

FIG. 18 is a diagram showing an incident angle of light to an optical element for color separation or color synthesis provided in an illumination optical system other than the telecentric optical system.

FIG. 19 is a diagram illustrating an example of a wavelength characteristic depending on an incident angle of a color separation mirror.

FIG. 20 is a diagram showing an incident angle of light to a color separating or color combining optical element provided in a telecentric optical system portion of the illumination optical system.

FIG. 21 is a diagram illustrating the relationship between the size of an object and an image of an imaging optical system and the distance between an object and a lens and between a lens and an image.

FIG. 22 is a diagram illustrating a configuration example of an illumination optical system of a conventional color projector device.

[Explanation of symbols]

1,2,11,12 reflection mirror, 3 prism,
3a, 3b Reflecting surface of prism, 21 light sources, 2
2,26 condenser lens, 23,27-33 spatial light modulator, 24,25 multi-lens array, 24
a, 25a, 61 individual lenses of a multi-lens array,
41, 43-46 polarizing beam splitter, 42
Color separation / combination prism, 51 Projection optical system, 52
screen

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 5/04 G02B 19/00 G02F 1/13 505 G03B 21/00 D 19/00 F21M 1/00 Q G02F 1/13 505 R 1/13357 G02F 1/1335 530 G03B 21/00 F-term (reference) 2H042 CA03 CA08 CA14 CA17 DB14 DD01 DD08 DE04 2H052 BA02 BA03 BA09 BA14 2H088 EA15 EA19 HA24 HA25 HA28 MA20 2H091 FA14Z FA21Z FA26X FA26Z FA26Z FA26Z FD01 LA11 3K042 AA01 BB01 BB11 BC09 BE08

Claims (6)

[Claims] A light source; a first multi-lens array for condensing light emitted from the light source; and a second multi-lens array for receiving light condensed by the first multi-lens array. An illumination optical device comprising: a condensing lens for condensing light from the second multi-lens array; a first reflecting surface for reflecting light from the condensing lens; and the first reflecting surface. And a second reflecting surface that reflects light from
An illumination optical device, comprising: a light beam from the condenser lens, a light beam from the first reflection surface, and a light beam from the second reflection surface, which are arranged so as to intersect each other. 2. The illumination optical device according to claim 1, wherein the first reflecting surface and the second reflecting surface are mutually 45 degrees apart.
An illumination optical device characterized by an angle of degrees. 3. The illumination optical device according to claim 1, wherein the first reflection surface and the second reflection surface are surfaces of the same prism. 4. A light source; a first multi-lens array for condensing light emitted from the light source; and a second multi-lens array for receiving light condensed by the first multi-lens array. And a first reflecting the light from the second multi-lens array.
And a second reflecting surface that reflects light from the first reflecting surface, wherein the first reflecting surface and the second reflecting surface are separated from the second multi-lens array. And the light flux from the first reflection surface and the light flux from the second reflection surface are arranged so as to intersect with each other, and among the first reflection surface and the second reflection surface, Characterized in that at least one of them is concave. 5. The illumination optical device according to claim 4, wherein the first reflection surface and the second reflection surface are the same prism surface. 6. A light source; a first multi-lens array for condensing light emitted from the light source; and a second multi-lens array for receiving light condensed by the first multi-lens array. A condenser lens that collects light from the second multi-lens array; a first reflection surface that reflects light from the condenser lens; and a light that reflects light from the first reflection surface A second reflection surface, light condensed by the condenser lens is incident, a spatial light modulator that modulates the light in accordance with an image signal, and light modulated by the spatial light modulator is incident A projection optical system, and a screen on which light from the projection optical system is projected, wherein the first reflection surface and the second reflection surface are configured such that the light beam from the condenser lens and the first The light beam from the reflecting surface and the light beam from the second reflecting surface are mutually Projector apparatus characterized by being arranged such that the difference.