JP2002277829A - Polarizing illuminator and projection-type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a small-sized and compact polarizing illuminator which has an integrator optical system and a polarized light converting optical system combined and has a high light utilization efficiency. SOLUTION: A polarizing illuminator 1 is provided with a light source part 2, which emits light having random directions of polarization, a first lens plate 3 which is constituted of many rectangular condenser lenses, having rectangular external forms and converges light emitted from the light source to form many secondary light source images, and a second lens plate 4, which is places in the vicinity of positions where the secondary light source images are formed and is provided with a condenser lens array, a polarized light separating prism array 420, a λ/2-phase difference plate 430, and an exit-side lens 440. Polarized light is separated at a stage, where minute secondary light source images are formed by the first lens plate 3 constituting the integrator optical system. Thus spatial spread of the optical path accompanied with separation of polarized light is suppressed to miniaturize the polarizing illuminator, regardless of the provision of the polarized light converting optical system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarized light illuminating apparatus for uniformly illuminating a rectangular illumination area or the like using polarized light having a uniform polarization direction. In addition, the present invention relates to a projection display device that modulates polarized light emitted from the polarized light illuminating device by a liquid crystal light valve to display an image on a screen in an enlarged manner.

[0002]

2. Description of the Related Art As an optical system for uniformly illuminating a rectangular illumination area such as a liquid crystal light valve, an integrator optical system using two lens plates is conventionally known. The integrator optical system is disclosed in, for example,
No. 6, published by No. 6, which has already been put into practical use as a lighting device of a projection display device using a liquid crystal light valve.

The integrator optical system is the same as that used in an exposure machine in principle, and divides a light beam from a light source by a plurality of rectangular condensing lenses constituting a first lens plate. Then, an image (light source image) cut out by each of the rectangular condenser lenses is placed on one illumination area via a second lens plate having a condenser lens group corresponding to each of the rectangular condenser lenses. To form a superimposed image. In this optical system, the light source light use efficiency (illumination efficiency) is improved, and the intensity distribution of light illuminating the liquid crystal light valve can be made substantially uniform.

On the other hand, in a general projection display device using a liquid crystal light valve of a type that modulates polarized light, only one kind of polarized light can be used. About half are not used. Therefore, proposals have been made to increase the light use efficiency by making unused light available. A typical example is EURODISPLAY '90 PROCE
As disclosed on pages 64 to 67 of EDINGS, a polarization conversion optical system mainly including a polarizing beam splitter and a λ / 2 retardation plate is used. The polarization conversion optical system converts a type of polarized light that cannot be used by a liquid crystal light valve into a type of polarized light that can be used by the liquid crystal light valve, thereby increasing the efficiency of use of the light source light.

[0005]

Here, by combining the above-described integrator optical system and polarization conversion optical system, it is possible to further improve the utilization efficiency of light from the light source light. However, when these are simply combined, the lateral width of the entire optical system is approximately doubled.
For this reason, unless a very large projection lens having a small F-number is used, not only the light use efficiency in the projection display device cannot be improved, but also it is difficult to achieve the miniaturization of the optical system.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a small and compact polarized light illuminating device having a high light use efficiency by combining an integrator optical system and a polarization conversion optical system.

Another object of the present invention is to use a small and compact polarizing illuminator having a high light utilization efficiency and a bright projection image without using a large-aperture projection lens having a small F-number. It is an object of the present invention to realize a projection display device capable of obtaining the following.

[0008]

In order to solve the above-mentioned problems, a polarized light illuminating apparatus according to the present invention comprises a light source section for emitting light having a random polarization direction, and a plurality of rectangular light condensing sections each having a rectangular outer shape. A lens plate formed of a lens, for condensing light emitted from the light source unit to form a plurality of secondary light source images, and disposed near a position where the plurality of secondary light source images are formed; A condenser lens array, a polarization separation prism array, and a polarization conversion element, wherein the condenser lens array is composed of a plurality of condenser lenses, and the polarization separation prism array is composed of the plurality of rectangular condenser lenses. Each of the plurality of condensed lights is separated into a pair of adjacent P-polarized light and S-polarized light, and includes a plurality of polarization beam splitters and a plurality of reflection mirrors. , The P bias The polarization direction of the light and the S-polarized light is aligned, and is disposed on the side of the exit surface of the polarization separation prism array, and the optical axis and the lens plate of the light source unit are positioned with respect to a system optical axis. A configuration is employed in which the polarizing beam splitter is disposed at a position parallelly moved by half the width of the polarizing beam splitter. Further, a lateral width of the condenser lens constituting the condenser lens array is equal to a lateral width of the polarizing beam splitter. Or
The width is equal to twice the width of the polarizing beam splitter, and the condenser lens is disposed at a position shifted toward the width direction of the polarizing beam splitter by half the width of the polarizing beam splitter. And

In the polarized light illuminating device of the present invention, a plurality of minute light beams (secondary light source images) are formed by the first lens plate including a plurality of minute rectangular condenser lenses, and these light beams are polarized in the direction of polarization. After being separated into different P-polarized light and S-polarized light, the polarization plane of one or both polarized lights is rotated so that the polarization planes are aligned. Therefore, it is possible to irradiate one type of polarized light having a uniform polarization direction. Therefore, high-quality illumination light with high light use efficiency can be obtained.

Although it is possible to construct a polarization illumination optical system by simply using a polarization beam splitter, in this case, the width of the entire optical system is approximately doubled. Inconveniences such as extremely difficult miniaturization occur. In the present invention, since the polarized light is separated using the process of generating a minute secondary light source image, which is a feature of the integrator optical system, the spatial spread of the optical path due to the polarized light separation can be suppressed. . Therefore, the polarization illuminating device can be reduced in size despite having the polarization conversion optical system.

On the other hand, a projection type display device according to the present invention is characterized in that a polarization illuminating device having the above configuration is provided as an illuminating device.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a polarized light illuminating device according to the present invention, the condenser lens constituting the second lens plate is
The first lens plate may have a shape similar to that of the rectangular condenser lens.

Alternatively, the size and shape of each of the condensing lenses constituting the second lens plate may be different. That is, in correspondence with the size and shape of the secondary light source image formed by each of the rectangular condensing lenses constituting the first lens plate,
A configuration may be adopted in which the size and shape of each of the polarizing beam splitters on which these secondary light source images are formed are set. In this case, each condensing lens constituting the second lens plate is also set to have a size and shape corresponding to the size and shape of the corresponding polarizing beam splitter.

In this manner, each of the condensing lenses and the polarizing elements are made to correspond to the size and shape of the secondary light source image to be formed, that is, to have a size and shape sufficient to include the secondary light source image. By setting the size and shape of the beam splitter, the light use efficiency can be improved.
In addition, the illuminance distribution can be made uniform.

In general, a large secondary light source image is formed on the center side, which is closer to the system optical axis, and the smaller the secondary light source image is formed toward the peripheral side. Therefore, the condensing lens and the polarizing beam splitter on the center side should be made large, and those on the peripheral side should be made small.

Here, the condenser lenses having the same size and shape are used, and only the polarization beam splitters have the size and shape corresponding to the secondary light source image to be formed. You may do so. Also in this case, the light use efficiency can be improved and the illuminance distribution can be made uniform.

Next, 2 formed by the first lens plate
The light source section needs to be arranged such that the light source optical axis forms a slight angle with respect to the system optical axis so that the next light source image is located at the portion of the polarization beam splitter. Instead, by arranging the variable-angle prism, the light source optical axis R can be made coincident with the system optical axis L, and the light source unit can be disposed without tilting. For example, between the light source unit and the first lens plate,
A configuration in which a variable-angle lens is arranged can be adopted. The variable-angle lens can be integrated with the first lens plate.

Instead of using a variable angle lens, a rectangular condensing lens constituting the first lens plate may be an eccentric lens. Instead, the condenser lens constituting the condenser lens array on the side of the second lens plate may be an eccentric lens. When the condenser lens constituting the condenser lens array on the side of the second lens plate is an eccentric lens,
By adjusting the amount of eccentricity of each eccentric lens and the angle of the reflection film of the reflection mirror, it is possible to omit the emission side lens which is a component of the second lens plate.

On the other hand, instead of configuring the optical system so that the light source optical axis of the light source section is inclined with respect to the system optical axis, the following configuration is adopted to use the secondary light source formed by the first lens plate. The image can also be located on the polarizing beam splitter. In other words, the optical system may be configured such that the optical axis of the light source is translated with respect to the system optical axis by half the width of the polarizing beam splitter in the arrangement direction of the polarizing beam splitter. In this case, the first lens plate is also moved in the same direction by the same amount in parallel with the movement of the light source optical axis, and the center of the first lens plate is aligned with the light source optical axis.

The condensing lens constituting the condensing lens array of the second lens plate actually has a portion corresponding to the width of the polarizing beam splitter. Therefore, the width of each condensing lens may be set to a dimension at least equal to the width of the polarizing beam splitter.

As the λ / 2 retardation plate, a TN (twisted nematic) liquid crystal can be used.

Next, the above-mentioned polarized light separating prism array has a prism prism composite body having a polarized light separating film formed therein as a polarizing beam splitter, and a reflective film formed inside as a reflecting mirror. A structure having a formed quadrangular prism composite can be adopted.

In this case, the prism composite formed with the polarization separation film and the prism composite formed with the reflection mirror are:
It is possible to adopt a configuration in which they are arranged in a line in a direction perpendicular to the system optical axis.

For example, the prism composite formed with the polarization splitting film and the prism composite formed with the reflection mirror are alternately arranged in a direction perpendicular to the optical axis of the system optical axis, and each of the polarization splitting films is arranged separately. Are arranged so as to have substantially the same inclination angle with respect to the system optical axis.

Instead, a prism composite formed with a polarization splitting film and a prism composite formed with a reflection mirror are arranged in a direction perpendicular to the system optical axis, and each of the polarization splitting films is arranged in the system. On both sides of the optical axis,
A configuration in which the light sources are arranged so as to have a symmetrical inclination angle with respect to the optical axis may be employed.

On the other hand, in the projection display device of the present invention provided with the polarized light illuminating device of each of the above structures, generally, a color light separating means for separating a light beam from the polarized light illuminating device into at least two light beams; Color light combining means for combining modulated light fluxes modulated by the modulation means, and the combined light flux obtained by the color light combining means is projected and displayed as a color image on a screen via a projection optical system. You.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic structural view of a main part of a polarized light illuminating device of Embodiment 1 as viewed in plan. The polarized light illuminating device 1 of the present embodiment is generally constituted by a light source unit 2, a first lens plate 3, and a second lens plate 4 arranged along the system optical axis L. Light emitted from the light source unit 2 is condensed into the second lens plate 4 by the first lens plate 3, and the polarization direction of the randomly polarized light is aligned in the process of passing through the second lens plate 4. It is converted into one kind of polarized light, and the illumination area 5
Has been reached.

The light source unit 2 is generally constituted by a light source lamp 201 and a parabolic reflector 202. The randomly polarized light emitted from the light source lamp 201 is reflected in one direction by the parabolic reflector 202, and is incident on the first lens plate 3 as a substantially parallel light flux. Here, instead of the parabolic reflector 202, an elliptical reflector, a spherical reflector, or the like can be used.
The light source optical axis R is inclined by a certain angle with respect to the system optical axis L.

FIG. 2 shows the appearance of the first lens plate 3. As shown in this figure, the first lens plate 3 has a configuration in which a plurality of minute rectangular condenser lenses 301 having a rectangular outline are arranged vertically and horizontally. The light incident on the first lens plate 3 forms the same number of condensed images as the number of the rectangular condensing lenses 301 in a plane perpendicular to the system optical axis L by the condensing action of the rectangular condensing lens 301. Since the plurality of condensed images are nothing but the projection images of the light source lamps, they are hereinafter referred to as secondary light source images.

Next, the second lens plate 4 of this embodiment will be described with reference to FIG. The second lens plate 4 includes a condenser lens array 410, a polarization separation prism array 420,
This is a composite laminate composed of a λ / 2 retardation plate 430 and an emission side lens 440,
It is arranged in a plane perpendicular to the system optical axis L near the position where the next light source image is formed. This second
The lens plate 4 has a function as a second lens plate of the indexer optical system, a function as a polarization separation element, and a function as a polarization conversion element.

The condenser lens array 410 has substantially the same configuration as the first lens plate 3. That is, a plurality of the same number of condensing lenses 411 as the rectangular condensing lens 301 constituting the first lens plate 3 are arranged.
Has the effect of condensing light from Condensing lens array 41
0 corresponds to the second lens plate of the integrator optical system.

The condenser lens 411 constituting the condenser lens array 410 and the rectangular condenser lens 301 constituting the first lens plate 3 do not need to have exactly the same dimensions and lens characteristics. It is desirable that each be optimized according to the characteristics of the light from the light source unit 2. However, it is ideal that the light incident on the polarizing beam prism array 420 has a chief ray inclined parallel to the system optical axis L. From this point, the condenser lens 411 has the same lens characteristics as the rectangular condenser lens 301 constituting the first lens plate 3 or has the same shape as the rectangular condenser lens 301. It often has characteristics.

FIG. 3 shows the appearance of the polarization separating prism array 420. As shown in this figure, the polarization splitting prism array 420 includes a polarization beam splitter 4 composed of a prismatic prism composite having a polarization splitting film inside.
21 and a reflecting mirror 422 also formed of a prismatic prism composite having a reflecting film therein as a basic structural unit, and a plurality of such pairs are arranged in a plane (a plane on which a secondary light source image is formed). Are arranged within). The pair of basic constituent units are regularly arranged so as to correspond to the condenser lens 411 constituting the condenser lens array 410. Also, one polarization beam splitter 42
One lateral width Wp is equal to the lateral width Wm of one reflection mirror 422. Further, in this example, the width of the condensing lens 411 constituting the condensing lens array 410 is １ ／ of the width thereof.
The values of Wp and Wm are set, but are not limited thereto.

Here, the second lens plate 4 including the polarization separation prism array 420 is arranged so that the secondary light source image formed by the first lens plate 3 is located at the portion of the polarization beam splitter 421. I have. For this purpose, the light source unit 2 is arranged such that the light source optical axis R makes a slight angle with respect to the system optical axis L.

Referring to FIG. 1 and FIG. 3, random polarized light incident on the polarization splitting prism array 420 is converted into two types of polarized lights of P-polarized light and S-polarized light having different polarization directions by the polarization beam splitter 421. Is separated into The P-polarized light passes through the polarization beam splitter 421 without changing the traveling direction. On the other hand, the S-polarized light is reflected by the polarization splitting film 423 of the polarization beam splitter 421 to change the traveling direction by about 90 degrees, and the adjacent reflection mirror 422
The light is reflected by the reflection surface 424 of the (a pair of reflection mirrors), changes the traveling direction by about 90 degrees, and is finally emitted from the polarization separation prism array 420 at an angle substantially parallel to the P-polarized light.

On the exit surface of the polarization separating prism array 420, a λ / 2 phase difference film 431 is regularly arranged, and
A retardation plate 430 is provided. That is, the λ / 2 retardation film 431 is disposed only on the exit surface of the polarization beam splitter 421 included in the polarization separation prism array 420, and the λ / 2 retardation film 431 is disposed on the exit surface of the reflection mirror 422. Not. By such an arrangement state of the λ / 2 retardation film 431, the polarization beam splitter 4
The P-polarized light emitted from 21 is converted to a λ / 2 retardation film 431.
Is converted into S-polarized light by the rotation of the plane of polarization. On the other hand, since the S-polarized light emitted from the reflection mirror 422 does not pass through the λ / 2 phase difference film 431, it does not undergo any rotation of the polarization plane and passes through the λ / 2 phase plate 430 as it is S-polarized light. . To summarize the above, random polarized light is one kind of polarized light (S-polarized light in this case) by the polarization separating prism array 420 and the λ / 2 retardation plate 430.
Has been converted to

The light beam thus aligned to the S-polarized light is guided to the illumination area 5 by the exit lens 440.
It is superimposed on the illumination area 5. That is, the image plane cut out by the first lens plate 3 is superimposed and formed on the illumination area 5 by the second lens plate 4. At the same time, random polarized light is spatially separated into two kinds of polarized lights having different polarization directions by the polarization separating prism array 420 on the way, and when passing through the λ / 2 retardation plate 430, one kind of polarized light is And almost all light reaches the illumination area 5. Therefore, the illumination area 5 is almost uniformly illuminated with one type of polarized light.

As described above, according to the polarized light illuminating apparatus 1 of the present embodiment, the randomly polarized light radiated from the light source unit 2 is polarized by the first lens plate 3 into the polarized light separating prism array 42.
After condensing on a predetermined minute area of 0 and spatially separating into two kinds of polarized lights having different polarization directions, each polarized light is guided to a predetermined area of the λ / 2 retardation plate 430, and the P The light is converted to S-polarized light. Therefore, there is an effect that the illumination region 5 can be irradiated with the randomly polarized light emitted from the light source 2 almost aligned with the S polarized light. Further, since there is almost no light loss in the process of converting polarized light, there is a feature that the light source light utilization efficiency is extremely high.

Further, in the present embodiment, the minute rectangular condenser lens 301 constituting the first lens plate 3 is formed into a horizontally long rectangular shape in accordance with the shape of the illumination region 5 which is a horizontally long rectangular shape. The two types of polarized light emitted from the separation prism array 420 are separated in the horizontal direction. For this reason, even when illuminating the illumination region 5 having a horizontally long rectangular shape, the illumination efficiency can be increased without wasting the light amount.

In general, when a randomly polarized light is simply separated into a P-polarized light and an S-polarized light using a polarizing beam splitter, the width of the light beam emitted from the polarizing beam splitter is doubled, and the optical system is correspondingly expanded. It becomes large. However, in the polarized light illuminating device of the present invention, the process of generating a minute secondary light source image, which is a feature of the integrator optical system, is effectively used to absorb the spread of the luminous flux width caused by separating polarized light. As a result, the width of the light beam is not widened, and a small optical system can be realized.

(Embodiment 2) In the first embodiment, the light source unit 2 has its light source optical axis R set so that the secondary light source image formed by the first lens plate 3 is located at the polarization beam splitter 421. Had to be arranged at a slight angle with respect to the system optical axis L. However, by disposing the deflecting prism, the light source optical axis R was coincident with the system optical axis L, and the light source section was not tilted. Can be arranged.

The polarization illuminating device 10 according to the second embodiment shown in FIG. 4 is an example using a variable-angle prism. As shown in this figure, in the polarized light illumination device 10, the variable-angle prism 6 is arranged between the light source unit 2 and the first lens plate 3. The light incident on the deflecting prism 6 from the light source unit 2 is slightly bent in the traveling direction by the deflecting prism, and is incident on the first lens plate 3 with a certain angle that is not perpendicular. Reach the position.

As described above, the position of the secondary light source image formed by the first lens plate 3 can be freely set by installing the variable-angle prism 6. Therefore, the light source unit 2
Can be arranged on the system optical axis L, and the production of the optical system becomes simpler and easier.

In this embodiment, the variable-angle prism 6 is connected to the first
Of the lens plate 3 on the incident side. Therefore, it is possible to reduce the number of interfaces between the variable-angle prism 6 and the first lens plate 3 that cause a reflection loss of light. By integrating the variable-angle prism 6 with the first lens plate 3, light from the light source unit 2 can be guided to the second lens plate 4 without loss.

(Embodiment 3) In order to arrange the light source unit 2 which needs to be arranged slightly inclined with respect to the system optical axis L on the system optical axis L, the above-mentioned embodiment 2 is required. In addition to the method described above, the present invention can also be realized by a method in which the rectangular condenser lens 301 constituting the first lens plate 3 is an eccentric lens. Embodiment 3 shown in FIG. 5 is a polarized light illuminating device having such a configuration.

As shown in FIG. 5, the lighting device 100 of this embodiment
In the first embodiment, the first lens plate 3 is constituted by the eccentric minute condensing lens 310, the principal ray of the light beam emitted from the first lens plate 3 is slightly inclined, and the secondary light source image is set at a predetermined position of the polarizing beam splitter 421. Is set to be formed. For this reason, the light source unit 2 can be arranged on the system optical axis L, and the fabrication of the optical system becomes simpler and easier.

Fourth Embodiment Each of the second lens plates 4 used in the first to third embodiments has a condenser lens array 410 and an emission-side lens 440. Since the light incident on the polarizing beam prism array 410 is ideally such that the inclination of the principal ray is parallel to the system optical axis L, the condensing lens array 421 has a rectangular shape forming the first lens plate 3. In many cases, the same lens as the condenser lens 301 is used.
This is necessary for superimposing and coupling light beams passing through different positions on the lens plate 4 apart from the system optical axis L onto a predetermined illumination area 5.

However, the condensing lens array 410 is formed as an eccentric lens, and the reflecting surface 42 of the reflecting mirror 422 is formed.
By devising the installation angle of the output lens 4,
It is possible to omit 0. FIG. 6 shows a polarized light illuminating apparatus according to the fourth embodiment having this configuration.

As shown in FIG. 6, in this example, the condensing lens array 410 is configured by using the decentered condensing lenses 412 and 413, so that the condensing lens array 410 passes through the polarizing beam splitter 421. The principal ray of the P-polarized light can be directed to the center 51 of the illumination area.
The luminous flux passing through the polarizing beam splitter 421 at a position away from the system optical axis L can be dealt with by increasing the amount of eccentricity of the eccentric focusing lens 412. On the other hand, even for the S-polarized light emitted through the polarizing beam splitter 421 and the reflecting mirror 422, the principal angle of the S-polarized light is illuminated by setting the setting angle of the reflecting surface 424 of the reflecting mirror 422 to an appropriate value. It can be directed to the center 51 of the area. Of course, in this case, the system optical axis L
It is necessary to individually optimize the installation angle of the reflecting surface according to the distance from the camera.

With the above configuration, the emission side lens 440 becomes unnecessary, and the cost of the optical system can be reduced.

Further, in the configuration in which the exit side lens is not used as in this example, the installation place of the condenser lens array 410 is not limited to the light source side of the polarization separation prism array 420, and the condenser lens array 410 is Depending on the lens characteristics of the decentered condensing lenses 412 and 413 and the arrangement angle of the polarization separation films 423 and the reflection films 424 of the polarization separation prism array 420, the light collection lens array 410 is more illuminated than the polarization separation prism array 420. 5 can also be installed.

(Embodiment 5) In each of Embodiments 1 to 3, the light source unit 2 and the first lens plate 3 are arranged on the system optical axis L in any case, and the direction of the light source unit 2 or By adjusting the lens characteristics of the first lens plate 3, a secondary light source image is formed at a predetermined position of the polarizing beam splitter 421. The light source unit 2 and the first
The same result can be obtained by moving the lens plate 3 in parallel with the system optical axis.

Further, focusing on the lateral size (width) of the condenser lens 411 constituting the condenser lens array 410 of the second lens plate 4, the image forming position of the secondary light source image is always a polarizing beam splitter. Since the width is limited to the width 421, it can be understood that the condensing lens 411 functions sufficiently if the width is equal to the width Wp of the polarization beam splitter 421.

A specific example incorporating the above contents is shown in FIG. 7 as a polarized light illumination device 300 according to the fifth embodiment. In this example, the polarization separation prism array 420 is moved by an amount (= D) corresponding to １ ／ of the width Wp of the polarization beam splitter 421 with respect to the system optical axis L.
In FIG. 7, the light source unit 2 and the first lens plate 3 are arranged in a state of being translated in a direction in which the polarizing beam splitter 421 exists (downward in the figure). Further, a lens width (width) equal to the width Wp of the polarization beam splitter 421.
The condensing lens array 410 of the second lens plate 4 is configured by arranging the converging half lenses 414 having the following in accordance with the location of the polarization beam splitter.

With the above configuration, the design of the optical system is facilitated and the cost of the optical system can be reduced.

(Modification of Fifth Embodiment) In the fifth embodiment, focusing on the fact that the image forming position of the secondary light source image is always limited on the polarizing beam splitter 421, The width of the polarizing beam splitter 42
Condensing half lens 414 having a size equal to the width Wp of 1
You are using Such a condensing half lens 414
Is manufactured by cutting both ends of a normal condenser lens, for example, the condenser lens 411 shown in the first to third embodiments.

However, in some cases, the use of the ordinary condenser lens 411 as shown in Embodiments 1 to 3 may be more advantageous in terms of cost and the like than the adoption of the condenser half lens 414.

FIG. 8 shows a configuration example in which the condensing lens 411 used in the first to third embodiments is used instead of the converging half lens 414 in consideration of this point. The overall configuration of the polarized light illuminating device 300A shown in this drawing is the same as that of the polarized light illuminating device 300 according to the fifth embodiment. The difference is that the condensing lens constituting the condensing lens array 410 is not a half lens but a condensing lens 4 similar to that used in the first to third embodiments.
11 and that the condensing lenses 411 have their widths Wp toward the width direction of the polarizing beam splitter 421.
In the position moved by half the amount of.

(Embodiment 6) In each of the above embodiments, the polarization beam splitting film 423 of the polarization beam splitter 421 formed on the polarization beam splitting prism array 420, which is one of the components of the second lens plate 4, Reflection mirror 4
The reflection surfaces 424 of 22 are inclined in the same direction with respect to the system optical axis L. Instead of employing this configuration, a configuration in which the inclination directions of the polarization separation film 423 and the reflection film 424 are symmetrical with respect to the system optical axis L may be employed.

FIG. 9 shows a polarized light illuminating device 500 in which a polarized light separating prism array having this structure is incorporated. The polarized light illuminating device 500 of the present example also has the light source unit 2 disposed along the system optical axis L, similarly to the above-described embodiments.
It is roughly composed of a first lens plate 3 and a second lens plate 4. Light emitted from the light source unit 2 is condensed into the second lens plate 4 by the first lens plate 3, and the polarization direction of the randomly polarized light is aligned in the process of passing through the second lens plate 4. The light is converted into one kind of polarized light and reaches the illumination area 5.

In the first lens plate 3 of the polarized light illuminating device 500, a minute condenser lens 311 composed of an eccentric lens is arranged on the system optical axis L side, which is the center side, and a normal condensing lens 311 is disposed outside the first condensing lens. The minute condenser lenses 312 are arranged. The minute condenser lens 311 formed of an eccentric lens is arranged axially symmetrically with respect to the system optical axis L, so that the brightness in the illumination area 5 is made uniform.

The second lens plate 4 is provided with a condensing lens array 410, a polarization separation prism array 420, a λ / 2 retardation plate 430,
And the emission-side lens 440 are arranged in this order. The second lens plate 4 is the first lens plate 3
Are located in a plane perpendicular to the system optical axis L near the position where the secondary light source image is formed.

In the condenser lens array 410, each minute condenser lens 31 composed of an eccentric lens of the first lens plate 3
In the vicinity of the position where the secondary light source image 1 is formed, a condenser lens 415 also formed of an eccentric lens is arranged. In addition, an ordinary concentric condenser lens 416 is disposed in the vicinity of the position where the secondary light source image is formed by each minute condenser lens 312 on the first lens plate 3. Here, each condenser lens 415, 416 constituting the condenser lens array 410
Is set large enough to include the secondary light source image formed here. That is, the secondary light source image formed on the center side of the system optical axis L is larger than the secondary light source image formed on the outer peripheral side. For this reason, in this example,
The side of the system optical axis L, that is, the condenser lens array 410
The size of the decentered condensing lens 415 located on the center side is set to be larger than the size of the condensing lens 416 located on the peripheral side.

As described above, the condenser lens 415 constituting the condenser lens array 410 on the second lens plate 4 side,
Since the size of the second lens plate 416 is different between the center side and the peripheral side of the second lens plate,
The polarization beam splitter 421 formed on the polarization separation prism array 420 disposed on the output side
Correspondingly, the dimensions of A, 421B and the reflection mirrors 422A, 422B are larger on the central side than on the peripheral side.

In the polarizing prism array 410 of this embodiment, a polarizing beam splitter 421A having a polarization separating film 423A formed therein is disposed in a symmetrical manner in the width direction about the system optical axis L. On both sides of these, a reflection mirror 422A having a reflection film 424A formed therein is disposed. Further, a reflection mirror 422B of a small size is arranged on each of these sides. The reflection film 424B formed on the small-size reflection mirror 422B is inclined in the opposite direction to the reflection film 424A of the large-size reflection mirror 422A located inside. The small-sized polarizing beam splitters 4 are provided on both sides of the small-sized reflecting mirror 422B having this configuration.
21B are arranged. The polarization separation film 423B formed on these polarization beam splitters 421B is also
The polarization beam splitter 421A of a large dimension located inside is inclined in the opposite direction to the polarization separation film 423A.

As described above, the condensing lens and the polarization splitting prism array 420 constituting the condensing lens array 410 are adjusted in accordance with the position and size of the secondary light source image formed by the first lens plate 3. By optimizing the dimensions and shape of the polarizing beam splitter and the reflecting mirror to configure,
There is an effect that the use efficiency of the light source light can be further improved and the second lens plate 4 can be downsized.

(Embodiment 7) In Embodiment 6 described above, the condensing lens array 410 of the second lens plate 4 corresponding to the size of the secondary light source image formed by the first lens plate 3
Are set for the size and shape of each condenser lens. Similarly, the dimensions and shapes of the polarization beam splitters and the reflection mirrors constituting the polarization separation prism array 420 are set.

However, the condensing lens array 410 is constituted by using condensing lenses having the same dimensions and shape, and the size of each prism constituting the polarization separating prism array 420, that is, the polarization beam formed on them Only the dimensions and shapes of the splitter and the reflection mirror may be made to correspond to the size of the secondary light source image.

FIG. 10 shows an example of a polarized light illuminating device having this configuration. Polarized illumination device 600 shown in this figure
Has basically the same configuration as that of the polarized light illumination device 300A which is a modification of the fifth embodiment described above. Therefore, the characteristic portions will be described below.

In the polarized light illuminating apparatus 600 of this embodiment, the condensing lens arrays 410 constituting the second lens plate 4 have the same shape and the same size as the condensing lenses 416A to 416.
D.

However, the polarization separation prism array 420
The sizes of the polarizing beam splitter and the reflecting mirror formed in the above are changed according to the size of the formed secondary light source image. That is, since the secondary light source image formed on the center side on the side of the system optical axis L is large, a large polarizing beam splitter 425A and a reflection mirror 425B are arranged correspondingly. On the other hand, on the peripheral side far from the system optical axis L, the formed secondary light source image is relatively small, and accordingly, a relatively small polarizing beam splitter 426A and a reflection mirror 426B are arranged correspondingly. I have.

Here, each of the lenses 314A to 314D constituting the first lens plate 3 and each of the condenser lenses 416A to 416D constituting the condenser lens array 410 on the second lens plate 4 side. Uses eccentric lenses for some of these lenses. Further, similarly to the above-described fifth embodiment, an arrangement is used in which the light source optical axis R is translated from the system optical axis L by a fixed distance D in parallel. In addition,
The first lens plate 3 is also translated in the same direction by the same amount so that its center coincides with the optical axis of the light source.

By adopting these configurations, the first
The secondary light source image obtained through the lens plate 3 is formed on the polarizing beam splitter.

The value of the distance D in FIG. 10, the condenser lenses 314A to 314D, and which of the condenser lenses 416A to 416D are to be used as the eccentric lens, and the eccentric lens to be used. The amount of eccentricity of the optical system is determined by the design of the optical system. Therefore, these items are not uniquely determined, but are to be determined according to each specific device configuration.

In this embodiment, each of the condenser lenses 4 constituting the condenser lens array 410 on the side of the second lens plate 4
16A to 416D use concentric lenses.
However, as described above, the condensing lenses 416A to 416D having the same shape and the same size are bonded to the polarizing beam splitters 425A and 426A having different sizes, and therefore, their centers are shifted. Because of this, as a result, these concentric focusing lenses 416
A to 416D are equivalent to using an eccentric lens.

As described above, the polarized light illuminator 600 includes the condensing lenses 416A to 416D having a size corresponding to the size of the secondary light source image to be formed. With this configuration as well, the utilization efficiency of light can be improved, as in the sixth embodiment.

In this example, the condenser lens array 410 of the second lens plate 4 is composed of condenser lenses 416A to 416D having the same shape and the same dimensions. Therefore, there is also an advantage that the manufacture of the condenser lens array is easy.

FIG. 11 shows a projection type display using the polarized light illuminating device 100 shown in FIG. 5 among the polarized light illuminating devices of the first to sixth embodiments. An example of a type display device is shown.

As shown in FIG. 11, the polarized light illuminating device 100 of the projection type display device 3400 of this example includes a light source unit 2 for emitting randomly polarized light in one direction. The polarized light is guided to a predetermined position of the second lens plate 4 while being collected by the first lens plate 3, and then is separated by the polarization separation prism array 420 in the second lens plate 4. Separated into different types of polarized light. Further, among the separated polarized lights, the P-polarized light is λ
The light is converted into S-polarized light by the / 2 phase plate 430.

The light beam emitted from the polarized light illuminating device 100 is first converted to a blue-green reflecting dichroic mirror 340.
At 1, red light is transmitted and blue and green light are reflected. The red light is reflected by the reflection mirror 3402 and reaches the first liquid crystal light valve 3403. On the other hand, of the blue light and the green light, the green light is reflected by the green reflecting dichroic mirror 3404 and reaches the second liquid crystal light valve 3405.

Here, since blue light has the longest optical path length of each color light, the blue light has
406, relay lens 3408 and emission side lens 34
Light guide means 34 constituted by a relay lens system consisting of 10
50 are provided. That is, after transmitting the blue light through the green reflecting dichroic mirror 3404, first, the blue light is guided to the relay lens 3408 via the incident side lens 3406 and the reflecting mirror 3407, and the relay lens 3408
8, the light is guided to the emission side lens 3410 by the reflection mirror 3409, and then reaches the third liquid crystal light valve 3411. Here, the first to third liquid crystal light valves 3403, 3405, and 3411 modulate the respective color lights, include video information corresponding to each color, and then apply the modulated color lights to the dichroic prism 341.
3 (color combining means). In the dichroic prism 3413, a dielectric multilayer film for red reflection and a dielectric multilayer film for blue reflection are formed in a cross shape, and synthesize modulated light beams. The luminous flux synthesized here passes through a projection lens 3414 (projection unit) and passes through a screen 3415.
An image will be formed on top.

The projection display device 340 thus configured
At 0, a type of liquid crystal light valve that modulates one type of polarized light is used. Therefore, when random polarized light is guided to the liquid crystal light valve using a conventional lighting device, half of the random polarized light is absorbed by a polarizing plate (not shown) and converted into heat. However, there is a problem that a large-sized and noisy cooling device for suppressing the heat generation of the polarizing plate is required, as well as a low use efficiency. However, in the device 3400 of this example, such a problem is greatly improved.

That is, the projection display device 3400 of this embodiment
In the polarized light illuminating device 100, only one polarized light, for example, P-polarized light, is given a rotating action of the polarization plane by the λ / 2 retardation plate 430, and the other polarized light, for example, S
The polarized light and the plane of polarization are aligned. Therefore, the polarized light having the uniform polarization direction is supplied to the first to third liquid crystal light valves 34.
Since the light is guided to 03, 3405, and 3411, the light absorption by the polarizing plate is very small, and therefore, the light use efficiency is improved, and a bright projected image can be obtained.

Further, since the amount of light absorbed by the polarizing plate is reduced, a rise in temperature at the polarizing plate is suppressed. Therefore, the cooling device can be reduced in size and noise can be reduced, and a high-performance projection display device can be realized.

Further, in the polarized light illuminating device 100, two kinds of polarized light are separated in the horizontal direction in the second lens plate 4 in accordance with the shape of the condenser lens 411. Therefore, it is possible to form a horizontally long rectangular illumination area without wasting light. Therefore, the polarized light illumination device 1
00 is suitable for a horizontally long liquid crystal light valve capable of projecting a powerful image that is easy to see.

As described in connection with the first embodiment, in the polarized light illuminating device 100 of the present embodiment, the polarization conversion prism array 4 is provided although the polarization conversion optical element is incorporated.
The spread of the light beam exiting from the light source 20 is suppressed. This means that when illuminating the liquid crystal light valve, almost no light enters the liquid crystal light valve with a large angle. Therefore, a bright projected image can be realized without using an extremely large-diameter projection lens having a small F-number.

In this embodiment, since the dichroic prism 3413 is used as the color synthesizing means, the size can be reduced. Also, the liquid crystal light valves 3403 and 34
Since the optical path length between the lens elements 05 and 3411 and the projection lens 3414 is short, a bright projection image can be realized even with a projection lens having a relatively small aperture. Each color light has a different optical path length only in one of the three optical paths. In this example, the blue lens having the longest optical path length has an incident side lens 340.
6, relay lens 3408 and emission side lens 3410
Since there is provided the light guide means 3450 constituted by a relay lens system consisting of, the color unevenness and the like do not occur.

Incidentally, the projection type display device can also be constituted by a mirror optical system using two dichroic mirrors for the color synthesizing means. Of course, even in that case, the polarized light illuminating device of this embodiment can be incorporated, and a bright high-quality projected image with excellent light use efficiency can be formed as in the case of this embodiment.

(Other Embodiments) In each of the above-described embodiments, for example, P-polarized light is made to be S-polarized light by the polarization splitting means. Good. Further, a phase difference layer may impart a rotating action on the polarization plane to both the P-polarized light and the S-polarized light to make the polarization planes uniform.

On the other hand, in each embodiment, it is assumed that a λ / 2 retardation plate is formed of a general polymer film. However, these retardation plates may be configured using a twisted nematic liquid crystal (TN liquid crystal). When the TN liquid crystal is used, the wavelength dependence of the retardation plate can be reduced, so that the polarization conversion performance of the λ / 2 retardation plate can be improved as compared with the case where a general polymer film is used. .

[0092]

As described above, the polarized light illuminating device according to the present invention can irradiate the irradiated area with polarized light having a uniform polarization direction. Therefore, when the polarization illuminating device according to the present invention is used for a projection display device using a liquid crystal light valve,
Since polarized light having a uniform plane of polarization can be supplied to the liquid crystal light valve, the light utilization efficiency is improved, and the brightness of the projected image can be improved. Further, since the amount of light absorbed by the polarizing plate is reduced, a rise in temperature at the polarizing plate is suppressed. Therefore,
The cooling device can be reduced in size and noise can be reduced.

Further, in the present invention, the process of generating a minute secondary light source image, which is a feature of the integrator optical system, is used to avoid the spatial spread caused by the separation of polarized light. Therefore, in spite of the optical system having the polarization conversion element, the size of the device can be suppressed to the same size as the conventional lighting device.

Further, since a polarization beam splitter provided with a thermally stable dielectric multilayer film is used as the polarization separation means, the polarization separation performance of the polarization separation section is thermally stable. For this reason, a stable polarization separation performance can always be exhibited even in a projection display device requiring a large light output.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an optical system of a polarized light illumination device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a first lens plate of FIG. 1;

FIG. 3 is a perspective view of the polarization splitting prism array of FIG. 1;

FIG. 4 is a schematic configuration diagram illustrating an optical system of a polarized light illumination device according to a second embodiment of the present invention.

FIG. 5 is a schematic configuration diagram illustrating an optical system of a polarized light illumination device according to a third embodiment of the present invention.

FIG. 6 is a schematic configuration diagram illustrating an optical system of a polarized light illumination device according to a fourth embodiment of the present invention.

FIG. 7 is a schematic configuration diagram illustrating an optical system of a polarized light illumination device according to a fifth embodiment of the present invention.

8 is a schematic configuration diagram showing a modified example of the polarized light illumination device shown in FIG.

FIG. 9 is a schematic configuration diagram illustrating an optical system of a polarized light illumination device according to a sixth embodiment of the present invention.

FIG. 10 is a schematic configuration diagram illustrating an optical system of a polarized light illumination device according to a seventh embodiment of the present invention.

11 is a schematic configuration diagram of an optical system showing an example of a projection display device in which the polarized light illumination device of FIG. 5 is incorporated.

[Explanation of symbols]

1, 10, 100, 200, 300, 300A, 40
0, 500, 600 polarized light illumination device 2 light source unit 3 first lens plate 301 rectangular condenser lens 310, 311, 312, 314A to 314D rectangular condenser lens 4 second lens plate 410 condenser lens array 411, 412, 413 Condensing lens 414 Condensing half mirror 415 Eccentric condensing lens 416, 416A to 416D Condensing lens 420 Polarization separating prism array 421, 421A, 421B, 425A, 426A Polarizing beam splitter 422, 422A, 422B, 425B, 426B Reflection mirror 423, 423A, 423B Polarization separation film 424, 424A, 424B Reflection film 430 λ / 2 phase plate 440 Emission lens 5 Illumination area 6 Deflection prism 3400 Projection display device 3401 Blue-green reflection dichroic mirror 3402 Reflection Mirror 3403 Liquid crystal light valve 3404 Dichroic mirror 3405 Liquid crystal light valve 3405 3406 Incident lens 3407 Reflector mirror 3408 Relay lens 3450 Light guide 3410 Exit lens 3409 Reflector mirror 3411 Liquid crystal light valve 3413 Dichroic prism 3414 Projection lens (Screening means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) G02F 1/13357 G03B 21/14 A G03B 21/00 33/12 21/14 H04N 5/74 A 33/12 F21Y 101: 00 H04N 5/74 F21M 1/00 R // F21Y 101: 00 F term (reference) 2H088 EA15 EA47 HA13 HA16 HA18 HA25 HA28 MA04 MA06 2H091 FA05Z FA11Z FA29Z FA41Z LA03 LA17 LA18 MA07 2H099 AA12 BA09 BA04 CA08 CA08 AA01 AC06 BB03 BC09 BE08 5C058 AB03 BA05 BA23 EA01 EA02 EA12 EA14 EA26 EA42 EA51

Claims (13)

[Claims] 1. A light source unit for emitting light having a random polarization direction, and a plurality of rectangular condenser lenses having a rectangular outer shape. A lens plate for forming a secondary light source image, disposed near a position where the plurality of secondary light source images are formed, a condenser lens array, a polarization separation prism array, and a polarization conversion element, The condensing lens array is composed of a plurality of condensing lenses, and the polarization splitting prism array is a pair of adjacent P-polarized light and S-polarized light for each of the plurality of lights condensed by the plurality of rectangular condensing lenses. And is separated into
The polarization conversion element is composed of a plurality of polarization beam splitters and a plurality of reflection mirrors, and the polarization conversion element aligns the polarization directions of the P-polarized light and the S-polarized light, and is provided on an emission surface side of the polarization separation prism array. Wherein the optical axis of the light source unit and the lens plate are arranged at a position parallel to a system optical axis by an amount equal to a half of a width of the polarizing beam splitter; Wherein the width of the condenser lens is equal to the width of the polarization beam splitter. 2. A light source unit for emitting light having a random polarization direction, and a plurality of rectangular condenser lenses having a rectangular outer shape. A lens plate for forming a secondary light source image, disposed near a position where the plurality of secondary light source images are formed, a condenser lens array, a polarization separation prism array, and a polarization conversion element, The condensing lens array is composed of a plurality of condensing lenses, and the polarization splitting prism array is a pair of adjacent P-polarized light and S-polarized light for each of the plurality of lights condensed by the plurality of rectangular condensing lenses. And is separated into
The polarization conversion element is composed of a plurality of polarization beam splitters and a plurality of reflection mirrors, and the polarization conversion element aligns the polarization directions of the P-polarized light and the S-polarized light, and is provided on an emission surface side of the polarization separation prism array. Wherein the optical axis of the light source unit and the lens plate are arranged at a position parallel to a system optical axis by an amount equal to a half of a width of the polarizing beam splitter; The width of the condensing lens is equal to twice the width of the polarizing beam splitter, and the converging lens is directed toward the width direction of the polarizing beam splitter by half the width of the polarizing beam splitter. A polarized light illuminating device which is arranged at a moved position. 3. The polarized light illuminating device according to claim 2, wherein the rectangular condenser lens has a horizontally long rectangular shape. 4. The polarized light illuminating device according to claim 2, wherein the condensing lens forming the condensing lens array has a similar shape to the rectangular condensing lens forming the lens plate. . 5. A plurality of secondary light source images are formed by condensing light emitted from a light source unit, and the light forming the plurality of secondary light source images is respectively condensed by a condenser lens array and / or a lens. A polarized light illuminating device superimposed on an illumination area, wherein each of the lights forming the plurality of secondary light source images includes a plurality of polarization beam splitters and a plurality of reflection mirrors arranged alternately. By prism array,
The pair of adjacent P-polarized light and S-polarized light is separated into a pair of adjacent P-polarized light and S-polarized light.
Aligned by a polarization conversion element, the condenser lens array is composed of a plurality of condenser lenses, and the optical axis of the light source unit has been translated with respect to a system optical axis by an amount equal to half the width of the polarization beam splitter. A polarizing illuminator, which is disposed at a position, wherein a width of the condenser lens is equal to a width of the polarization beam splitter. 6. A plurality of secondary light source images are formed by condensing light emitted from the light source unit, and the light forming the plurality of secondary light source images is respectively condensed by a condenser lens array and / or a lens. A polarized light illuminating device superimposed on an illumination area, wherein each of the lights forming the plurality of secondary light source images includes a plurality of polarization beam splitters and a plurality of reflection mirrors arranged alternately. By prism array,
The pair of adjacent P-polarized light and S-polarized light is separated into a pair of adjacent P-polarized light and S-polarized light.
The light-condensing lens array is composed of a plurality of condensing lenses, and the optical axis of the light source unit is translated to the system optical axis by an amount equal to half the width of the polarization beam splitter. Wherein the width of the condensing lens constituting the condensing lens array is equal to twice the width of the polarizing beam splitter, and the condensing lens is half the width of the polarizing beam splitter. A polarization illuminating device, wherein the polarization beam splitter is disposed at a position shifted in a width direction of the polarization beam splitter. 7. The polarized light separating prism array according to claim 1, wherein the polarized light separating prism array has, as the polarized light beam splitter, a rectangular prism-shaped prism composite in which the polarized light separating film is formed. Along with
A polarized light illuminating device comprising, as the reflection mirror, a prism composite having a quadrangular prism shape having a reflection film formed therein. 8. The polarization illuminating device according to claim 1, wherein the polarization conversion element is formed of a retardation plate. 9. The method according to claim 8, wherein the phase difference plate is λ /
A polarized light illuminating device comprising a two-phase retarder. 10. The polarized light illuminating device according to claim 1, wherein the polarization conversion element is formed of a twisted nematic liquid crystal. 11. A projection display device comprising: the polarization illuminating device according to claim 1; and modulating and projecting a light beam from the polarization illuminating device. . 12. A polarized light illuminating device according to claim 1, and a liquid crystal light valve for modulating polarized light contained in a light beam from the polarized illuminating device to include image information. And a projection optical system for projecting and displaying the modulated light beam. 13. A color light synthesizing means according to claim 12, further comprising: a color light separating means for separating a light beam from said polarized light illuminating device into two or more light beams; And a combined light beam obtained by the color light combining means is projected and displayed via the projection optical system.