JPH08220475A - Polarizing illuminator and projection type display device using the same - Google Patents

Abstract

PURPOSE: To realize an illuminator stably demonstrating excellent performance under environments causing a remarkable change in temperature by using a polarizing separating means where the temperature stability of a polarizing separating angle is excellent and a projection type display device forming a bright projected video by improving light utility. CONSTITUTION: When random polarized light radiated from a light source 20 is separated into two kinds of the polarized light by a polarized light separation film 31 using a dielectric multilayer film layer at a polarized light separating part 30, polarized light P is converted into the polarized light S by the λ/2 phase difference plate 62 of a condensing lens 60 in the polarizing illuminator 10A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarized illuminating device for uniformly illuminating a specific rectangular area or the like by using polarized light whose polarization directions are uniform, and a polarized light emitted from this polarized illuminating device by a light valve. The present invention relates to a projection-type display device that modulates and displays an image enlarged on a screen.

[0002]

2. Description of the Related Art In a general projection display device using a liquid crystal light valve of the type that modulates polarized light, improvement of light utilization efficiency is one of the important problems to be solved. In order to solve the above-mentioned problems, for example, as disclosed in Japanese Patent Laid-Open No. 6-202094, a novel illumination optical system in which a polarization conversion method is combined with an integrator illumination method has been proposed.

The illumination optical system disclosed in the above publication is
As shown in FIG. 15A, a conventional integrator optical system is used as a base, and this integrator optical system 98 is used.
The lens 9 has a first lens plate 981 and a second lens plate 983. Here, the first lens plate 98
A polarized light separating means 982 is arranged in the vicinity of 1, and a λ / 2 retardation plate 984 is formed on the second lens plate 983. In the integrator optical system 989, the one having a plurality of minute rectangular lenses 985 shown in FIG. 15B is used as the first lens plate 981, and the same number as the rectangular lenses 985 is used as the second lens plate 983. The one provided with a minute lens is used. In the illumination optical system having such a configuration, first, polarized light emitted from the light source unit 986 with random polarization directions (actually, it is considered to be mixed light of P-polarized light and S-polarized light) is a liquid crystal material. The polarized light is incident on the polarized light separating means 982 as a main component, and is separated into P polarized light and S polarized light having slightly different outgoing angles due to the outgoing angle dependent characteristics of each polarized light which the polarized light separating means 982 has. The two polarized lights emitted from the polarized light separating means 982 are the first lens plate 98 of the integrator optical system 989.
1, and a pair of secondary light source images composed of a light source image of P-polarized light and a light source image of S-polarized light are formed in the second lens plate 983 by the condensing action. The number of the pair of secondary light source images is equal to the number of minute lenses forming the first lens plate. Here, since the λ / 2 phase difference plate 984 is arranged in the second lens plate 983 in accordance with each position where the secondary light source image is formed, this phase difference plate 984 is used for one polarized light ( For example, when P-polarized light passes, the polarized light is rotated by the polarization plane, and is guided to the illumination area 988 with the polarization plane aligned with the other polarized light (for example, S-polarized light). Get burned. Therefore, in this optical system,
By spatially separating the secondary light source image formed in the integrator optical system 989 according to the type of polarized light,
It is possible to convert the plane of polarization of specific polarized light.

[0004]

In the above-mentioned polarized illumination device, an optical system using a liquid crystal material is used as the polarized light separating means. In this optical system, the utilization efficiency of light is improved, so that a bright projected image is obtained. However, since the refractive index of liquid crystal materials is highly temperature-dependent, the polarization separation angle becomes unstable when incorporated in a light source system of a projection display device that causes a significant temperature change. There is a problem.

In view of the above problems, the object of the present invention is to
The purpose of the present invention is to realize a lighting device that can stably exhibit excellent performance even in an environment accompanied by a remarkable temperature change, by using a polarization separation means having an excellent temperature dependence of a polarization separation angle.

Another object of the present invention is to realize a projection type display device capable of forming a bright projected image by improving the light utilization efficiency by using such an illuminating device.

[0007]

In order to solve the above problems, in a polarized light illumination device according to the present invention, a light source section for emitting polarized light having a random polarization direction, and a polarization separation film composed of a dielectric multilayer film. Is sandwiched between two right-angled prisms, and the polarization separation film separates the polarized light emitted from the light source into two polarized lights, P-polarized light and S-polarized light, whose polarization directions are orthogonal to each other. And a plurality of minute condenser mirrors having a rectangular outer shape,
The first condensing mirror plate for condensing the P-polarized light emitted from the polarization separation unit to form a plurality of secondary light source images of the P-polarized light, and the first condensing mirror plate are almost the same. The S-polarized light having the same size and shape is condensed from the S-polarized light, and the S-polarized light is formed at a position slightly different from the position where a plurality of secondary light source images of the P-polarized light are formed. Multiple 2
A second condenser mirror plate for forming a secondary light source image;
Between the second condensing mirror plate and the polarization splitting section and between the second collecting mirror plate and the polarization splitting section.
/ 4 phase difference plate, a second λ / 4 phase difference plate, and a plurality of secondary light source images composed of P-polarized light and a plurality of secondary light source images composed of S-polarized light are formed in the vicinity of the position. Λ / 2 and a condenser lens plate arranged by the same number of minute lenses as the minute condenser mirrors constituting the first or second condenser mirror plate
It is characterized in that it is provided with a condenser lens portion including a retardation plate.

In the present invention, it is preferable that a variable angle prism is arranged between the light source section and the polarized light separating section.

Alternatively, in the present invention, the polarization splitting section and the first
It is preferable that the angle-changing prism is arranged between the condenser mirror plate and the condenser mirror plate and between the polarization splitting section and the second condenser mirror plate. In that case, it is preferable that the gonio prism is integrated with the polarization splitting unit, or the gon prism is integrated with the first condenser mirror plate and the second condenser mirror plate. Is preferably provided. Furthermore, it is preferable that the variable angle prism is integrated with the polarization splitting unit, the first light collecting mirror plate, and the second light collecting mirror plate.

In the present invention, the polarization separation section may be composed of a flat polarization separation plate.

Further, in the present invention, the right angle prism forming the polarized light separating portion may be a liquid filling prism.

Further, in the present invention, the λ / 2 retardation plate and the λ / 4 retardation plate may be formed of TN (twisted nematic) liquid crystal.

In the present invention, it is preferable that the separation directions of the two types of secondary light source images formed by the two condenser mirror plates coincide with the longitudinal direction of the illumination area.

Further, in the present invention, it is preferable that the minute lenses of the condenser lens plate are similar to the minute condenser mirrors.

In the projection display device according to the present invention using the polarized illumination device having the above-described structure, the light source section for emitting polarized light having a random polarization direction and the polarization separation film formed of a dielectric multilayer film are provided. This is a structure in which it is sandwiched by right-angled prisms, and the polarized light emitted from the light source unit is divided into two, P-polarized light and S-polarized light, whose polarization directions are orthogonal to each other.
The P polarized light emitted from the polarized light separating unit is composed of a polarized light separating unit that separates and emits two polarized light and a plurality of minute light collecting mirrors having a rectangular outer shape. A first condensing mirror plate for forming a plurality of secondary light source images, and a size and shape substantially the same as the first condensing mirror plate, and condensing S-polarized light emitted from the polarization separation unit. However, a plurality of S-polarized light beams are formed at positions slightly different from the positions at which a plurality of P-polarized light secondary light source images are formed.
A second condenser mirror plate for forming a secondary light source image;
Between the second condensing mirror plate and the polarization splitting section and between the second collecting mirror plate and the polarization splitting section.
/ 4 phase difference plate, a second λ / 4 phase difference plate, and a plurality of secondary light source images composed of P-polarized light and a plurality of secondary light source images composed of S-polarized light are formed in the vicinity of the position. Λ / 2 and a condenser lens plate arranged by the same number of minute lenses as the minute condenser mirrors constituting the first or second condenser mirror plate
A condensing lens unit formed of a phase difference plate, a color separation unit that separates light that has passed through the λ / 2 phase difference plate into respective color lights of three primary colors, and each color light is modulated based on a video signal from the outside 3 It is characterized in that a sheet of light valves, a color synthesizing means for synthesizing the modulated light of each color light modulated by the light valve, and a light projecting means for projecting the respective color light synthesized by the color synthesizing means on a screen are provided. Have.

Here, it is preferable that the color synthesizing means has a dichroic prism, and a light guiding means is provided in an optical path having the longest optical path length among the optical paths of the respective color lights from the color separating means to the respective light valves. .

[0017]

In the polarized illumination device according to the present invention, of the polarized light split into two by the polarized light splitting unit using the dielectric multilayer film, one or both polarized light is retarded by the phase difference layer. The rotation effect of the plane of polarization is given by to make the plane of polarization uniform. Therefore, it is possible to irradiate polarized light having the same polarization direction. Therefore, when the polarized illuminating device according to the present invention is used for the projection type display device using the liquid crystal light valve, 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, the temperature rise in the polarizing plate is suppressed. Therefore, downsizing and noise reduction of the cooling device can be realized. Moreover, since a thermally stable dielectric multilayer film is used as the polarization separation film,
The polarization separation performance of the polarization separation section is thermally stable. Therefore, a stable polarization separation performance is always exhibited even in a projection display device that requires a large light output.

[0018]

Embodiments of the present invention will be described with reference to the drawings. In each of Examples 1 to 10, polarized light having a random polarization direction (hereinafter, simply referred to as random polarized light) is aligned with S-polarized light, but of course, P-polarized light is used. There is no essential difference in the format of aligning. Further, both the P-polarized light and the S-polarized light may be rotated by the retardation layer so that the polarization planes are aligned.

[Embodiment 1] FIG. 1 is a schematic configuration diagram of a main part of a polarized light illuminating device of the present embodiment as seen in a plan view.

In FIG. 1, a polarized light illumination device 10A of this example.
Is a light source unit 20, a polarization splitting unit 30, a first condenser mirror plate 40, a second condenser mirror plate 50, and a condenser lens unit along the system optical axis L (L ′) that bends at a right angle. 6
The light beam having a value of 0 and emitted from the light source unit 20 is separated into two types of polarized light beams by the polarization separation unit 30,
The condensing mirror plate 40, the second condensing mirror plate 50, the polarization splitting unit 30, and the condensing lens unit 60 combine again into one type of polarized light flux and reach the rectangular illumination area 70. .

The light source section 20 is generally composed of a light source lamp 21 and a parabolic reflector 22, and the polarized light emitted from the light source lamp 21 and having a random polarization direction is
The light is reflected in one direction by the parabolic reflector 22, becomes a substantially parallel light beam, and is incident on the polarization separation unit 30. Here, instead of the parabolic reflector 22, an ellipsoidal reflector, a spherical reflector or the like can be used.

The polarization splitting unit 30 is a general rectangular column-shaped polarization beam splitter, that is, a polarization splitting film 31 made of a dielectric multilayer film is sandwiched between two glass right-angle prisms (triangular prisms) 32. It has a structure. At this time, the polarization separation film 31 is formed so as to form an angle α = 45 degrees with respect to the incident surface 301 of the polarization separation unit 30. However, the angle α formed by the polarization separation film 31 and the incident surface 301 is not limited to 45 ° and may be set according to the incident angle of the incident light beam from the light source unit 20.

A first λ / 4 phase difference plate 33 is provided on the first emission surface 302 of the polarization separation section 30, and a second emission surface 303 is provided.
A second λ / 4 phase difference plate 34 is formed on each of the first and second phase difference plates 34, and the first condensing mirror plate 40 and the second condensing mirror plate 40 are formed outside the phase difference plates so as to face substantially the center of the polarization separation section 30. A condenser mirror plate 50 is installed. As shown in FIG. 2, an external view of each of these condensing mirror plates is formed by arranging a plurality of the same minute condensing mirrors 41 each having a rectangular outer shape in a matrix, and the surface of which is made of general aluminum. The reflecting surface 42 is formed by a vapor deposition film. In this example, the reflecting surface 42 of the minute condenser mirror 41 is formed in a parabolic shape. However, the curvature shape of the reflecting surface 42 may be spherical, elliptical, or toric, and these may be set according to the incident angle of the incident light beam from the light source unit 20.

On the illumination area 70 side of the third exit surface 304 of the polarized light separating portion 30, a condenser lens portion 60 composed of a condenser lens plate 61 and a λ / 2 phase difference plate 62 is provided. After that, the first light collecting mirror plate 40 and the second light collecting mirror plate 50 are installed in a position perpendicular to the system optical axis L at a position where a secondary light source image is formed. The condensing lens plate 61 is a compound lens body including rectangular minute lenses 611 as shown in FIG. 15B, and the number of minute lenses constituting the condensing lens plate 61 is the first and the first. The number is equal to the number of minute condenser mirrors 41 constituting the two condenser mirror plates (40 and 50). In the case of this example, a decentering lens is used as a part of the plurality of minute lenses 611. Also,
λ / 2 retardation layer 6 formed on the λ / 2 retardation plate 62
21 is regularly formed in the secondary light source image formed by the S-polarized light and the P-polarized light so as to correspond to the position where the P-polarized light forms the secondary light source image.

The polarized illumination device 10 configured as described above.
In A, as shown in FIG. 1, randomly polarized light is radiated from the light source section 20 and is incident on the polarization separation section 30. The randomly polarized light incident on the polarization splitting unit 30 is
It can be considered as a mixed light of P-polarized light and S-polarized light, and the mixed light is polarized in the polarization splitting unit 30.
1 separates into two types of polarized light of P polarized light and S polarized light. That is, the P-polarized light included in the randomly polarized light passes through the polarization separation film 31 as it is, and the first exit surface 3
02, on the other hand, the S-polarized light is transmitted through the polarization separation film 31.
Is reflected by and changes its traveling direction to the second emission surface 303 of the polarization splitting unit 30.

The two types of polarized light separated by the polarization separation unit 30 pass through the λ / 4 phase difference plate, are reflected by the condenser mirror plate, and are polarized while passing through the λ / 4 phase difference plate again. At the same time that the traveling direction of light is reversed by about 180 degrees, the plane of polarization is rotated by 90 degrees. How the polarized light changes will be described with reference to FIG. In FIG. 3, the first or second condenser mirror plate (40 or 50) is shown as a planar mirror plate 332 for the sake of simplification of description. λ / 4 retardation plate 33
The P-polarized light 333 that has entered 1 is converted into clockwise circularly polarized light 335 by the λ / 4 retardation plate and reaches the mirror plate 332. The light is reflected by the mirror plate 332, but at the same time, the rotation direction of the plane of polarization also changes. That is, the clockwise polarized light is changed to the counterclockwise polarized light (the counterclockwise polarized light is changed to the clockwise polarized light). The traveling direction of the light is inverted by 180 degrees by the mirror plate 332, and at the same time, the left-handed circularly polarized light 33
The polarized light of 6 is converted into S-polarized light 334 when passing through the λ / 4 retardation plate 331 again. In addition, the S-polarized light is converted into P-polarized light through the same process.

Therefore, the P-polarized light reaching the first emission surface 302 is inverted by 180 degrees in the traveling direction of the polarized light by the first λ / 4 retardation plate 33 and the first condensing mirror plate 40. At the same time, it is converted into S-polarized light, reflected by the polarization separation film 31, changed in traveling direction, and travels toward the third emission surface 304. On the other hand, the S-polarized light that has reached the second emission surface 303 has its traveling direction reversed by approximately 180 degrees by the second λ / 4 phase difference plate 34 and the second condensing mirror plate 50. It is converted into P-polarized light, and this time it is transmitted through the polarization separation film 31 as it is, and heads for the third emission surface 304. That is,
At this time, the polarization separation film 31 also functions as a polarization combining film.

Since the first light collecting mirror plate 40 and the second light collecting mirror plate 50 are composed of the minute light collecting mirrors 41 having a light collecting function, the traveling direction of the polarized light is substantially reversed, and at the same time, A plurality of condensing images are formed in the same number as the minute condensing mirrors forming each condensing mirror plate. Since these condensed images are nothing but the light source images, they will be referred to as secondary light source images below.

At this time, the first collecting mirror plate 40 and the second collecting mirror plate 40
Of the light collecting mirror plates 50 are slightly tilted (the first light collecting mirror plate 40 is aligned with the system optical axis L ′, and the second light collecting mirror plate 50 is aligned with the system optical axis L). The secondary light source image formed by the P-polarized light and the secondary light source image formed by the S-polarized light are formed at slightly different positions from each other. Will be done. That is, the lens unit 60 is viewed from the illumination area 70 side.
FIG. 4 shows a secondary light source image formed by two types of polarized light when viewed from above. A secondary light source image C1 formed by P-polarized light (in a circular image, a region shaded upward to the left) ), And two secondary light source images C2 (region of the circular image with a diagonal line rising to the right) formed by the S-polarized light are formed in a state where they are aligned in the horizontal direction. . On the other hand, λ /
In the two phase difference plate 62, the phase difference layer 621 is selectively formed corresponding to the formation position of the secondary light source image C1 by the P polarized light. Therefore, the P-polarized light is rotated by the plane of polarization when passing through the retardation layer 621, and the P-polarized light is converted into S-polarized light. On the other hand, since the S-polarized light does not pass through the retardation layer 621, the S-polarized light passes through the λ / 2 retardation plate 62 without being rotated by the polarization plane. Therefore, most of the light flux emitted from the condenser lens unit 60 is aligned with the S-polarized light.

The light flux thus converted into S-polarized light is applied to the illumination area 70 by the condenser lens section 60. That is, the image planes cut out by the minute condenser mirrors 41 of the first condenser mirror plate 40 and the second condenser mirror plate 50 are superposed and imaged at one place by the condenser lens plate 61, and λ / Since almost all the light reaches the illumination area 70 by being converted into one type of polarized light when passing through the two phase difference plate 62, the illumination area 70 is uniformly illuminated with almost one type of polarized light.

As described above, according to the polarized light illuminating device 10A of the present example, the random polarized light emitted from the light source section 20 is directionally separated into two types of polarized light by the polarization separating section 30, and then each polarized light is polarized. The light is guided to a predetermined area of the λ / 2 retardation plate 62 to convert the P polarized light into the S polarized light. Therefore, it is possible to irradiate the illumination region 70 with the randomly polarized light emitted from the light source unit 20 almost aligned with the S polarized light.

Moreover, each of the two types of polarized light is λ / 2.
To guide the light to a predetermined area of the retardation plate 62, the polarization splitting unit 30
It is necessary that the polarization separation performance of is high, but in this example,
Since the polarization splitting section 30 is configured using the glass prism and the dielectric multilayer film made of an inorganic material, the polarization splitting performance of the polarization splitting section 30 is thermally stable. Therefore, even in an illuminating device that requires a large light output, a stable polarized light separating performance is always exhibited, so that a polarized illuminating device having satisfactory performance can be realized.

Further, in this example, the first condensing mirror plate 4 is matched with the shape of the illumination region 70 which is a horizontally long rectangular shape.
The minute condenser mirrors 41 of the 0 and second condenser mirror plates 50 have a horizontally long rectangular shape, and at the same time, two types of polarized light emitted from the polarization separation unit 30 are laterally separated. . Therefore, the illumination area 7 having a horizontally long rectangular shape
Even when 0 is formed, the illumination efficiency can be improved without wasting the light amount.

[Modification of First Embodiment] In the first embodiment, the λ / 2 phase difference plate 62 is arranged on the illumination area side of the condenser lens plate 61, but if it is near the position where the secondary light source image is formed. However, there is no limitation in other positions. For example, the λ / 2 retardation plate 62 may be arranged on the light source unit side of the condenser lens plate 61.

Further, although the minute lens 611 forming the condenser lens plate 61 is a horizontally long rectangular lens, its shape is not particularly limited. However, as shown in FIG.
The secondary light source image C1 formed by the polarized light and the secondary light source image C2 formed by the S-polarized light are formed in a state of being aligned in the horizontal direction. Therefore, the condenser lens plate is formed corresponding to the formation position of the image. 6
It is desirable to determine the microlenses 611 that make up one.

Further, two kinds of retardation layers having different characteristics are
It may be arranged at each of the condensing position of the P-polarized light and the condensing position of the S-polarized light so that one kind of polarized light having a certain specific polarization direction is aligned.

[Embodiment 2] In Embodiment 1, the first condensing mirror plate 4 is used to spatially separate the formation positions of the secondary light source image of P-polarized light and the secondary light source image of S-polarized light.
0 and the second light collecting mirror plate 50 are slightly tilted (the first light collecting mirror plate 40 is with respect to the system optical axis L ′, and the second light collecting mirror plate 50 is with the system). It was necessary to arrange the light beams so that they each form an angle of β ° with respect to the optical axis L. The mirror plate can be arranged perpendicular to the system optical axis L (or L '). As will be described later, if the vertical arrangement can be realized, the polarization splitting section 30 and the λ / 4 phase difference plate 33 are provided.
(Or the λ / 4 retardation plate 34) or the like can be easily integrated.

That is, the polarized light illumination device according to the second embodiment shown in FIG. 5 may be constructed. In this polarized light illumination device and each of the embodiments described below, the basic configuration is the same as that of the polarized light illumination device according to the first embodiment. Is omitted.

In the polarized illumination device 10B shown in FIG. 5, the variable angle prism 71 is disposed between the light source section 20 and the polarized light separating section 30. By arranging the variable angle prism 71 at this position, the first condensing mirror plate 40 becomes the system optical axis L ′.
It can be arranged at a position perpendicular to the above, and the optical system can be easily manufactured. Of course, if the direction of the variable angle prism 71 is reversed (in FIG. 5, the acute angle portion of the variable angle prism is arranged so as to face the second light collecting mirror plate 50), the first light collecting mirror. Instead of the plate 40, the second condenser mirror plate 50 can be arranged at a position perpendicular to the system optical axis L.

Further, the variable angle prism 71 is provided with a polarization separation unit 30.
Can be integrated with the gonio prism 7
1 has the effect of reducing the reflection loss of light at the interface between the incident light beam No. 1 and the incident surface 301 of the polarization splitting unit 30.

[Third Embodiment] In the second embodiment, since the gonio prism 71 is arranged between the light source section 20 and the polarization splitting section 30, the first converging mirror plate 40 is moved to the system optical axis L. (Or the second condenser mirror plate 50 can be arranged at a position perpendicular to the system optical axis L), and the polarization splitting portion 30 and the λ / 4 phase difference plate 33 (or the λ / 4 phase difference plate) can be arranged. 34) and the like, it is easy to integrate the same, but a specific example of the polarization illumination device 10C according to the third embodiment is as follows.
As shown in FIG.

In this example, a condenser mirror plate 72 whose appearance is shown in FIG. 7 is used. That is, the light incident surface 721 is a flat surface, and the reflection surface 723 is formed on the back surface of the glass block 722. With such a shape, as shown in FIG. 6, the exit surface (first exit surface 302 in this case) of the polarization splitting unit 30 and the λ / 4 phase difference plate (first λ in this case) are formed. / 4 phase difference plate 33) and the condensing mirror plate 72 (corresponding to the first condensing mirror plate in this case) can be integrated, and the optical system can be further downsized, and at the interface. This has the effect of reducing the reflection loss of light.

[Fourth Embodiment] Further, as in the polarized light illuminating device 10D shown in FIG.
And the first condenser mirror plate 40 and the second condenser mirror plate 5
It may be arranged at two positions of 0. In this case, the first condenser mirror plate 40 and the second condenser mirror plate 5
Both 0 are system optical axis L '(or system optical axis L)
Since it can be arranged in a position perpendicular to, the installation of the condenser mirror plate becomes easy.

In the case of this example, the gonio prism 71 is integrated with the first exit surface 302 and the second exit surface 303 of the polarization splitting section 30 by optical adhesion, and the light at the interface is integrated. The effect is to reduce the reflection loss of.

Further, the first λ / 4 phase difference plate 33 (or the second λ / 4 phase difference plate 34) is the first emission surface 302 (or the second emission surface 303) of the polarization separation section 30. ) And the variable angle prism 71.

[Fifth Embodiment] Further, the variable angle prisms 71 arranged at two positions in the fourth embodiment are arranged in a form integrated with the first light collecting mirror plate 40 and the second light collecting mirror plate 50. In that case, there is also an effect that the reflection loss of light at the interface can be reduced. A configuration example in that case is shown in FIG. 9 as a polarized illumination device 10E according to the fifth embodiment.
In this example, in order to integrate the variable angle prism 71 and the first light collecting mirror plate 40, and the variable angle prism 71 and the second light collecting mirror plate 50, the third embodiment has been described. The same condensing mirror plate 72 is used.

Further, the first λ / 4 phase difference plate 33 (or the second λ / 4 phase difference plate 34) is the first condensing mirror plate 4
0 (or the second condenser mirror plate 50) and the variable angle prism 7
You may arrange between 1.

[Embodiment 6] Further, as in the polarization illuminating device 10F shown in FIG. 10, the polarization splitting section 30, the first λ / 4 phase difference plate 33, the variable angle prism 71, and the first condensing unit. The mirror plate 40, the polarization splitting unit 30, the second λ / 4 phase difference plate 34, the gonio prism 71, and the second condenser mirror plate 5
It is also possible to integrate 0 and 0, in which case there is an effect that the reflection loss of light at the interface can be reduced and the entire optical system can be downsized. Also in this example, the same condensing mirror plate 72 as that shown in the third embodiment is used.

The first λ / 4 phase difference plate 33 (or the second λ / 4 phase difference plate 34) is the first condensing mirror plate 4
0 (or the second condenser mirror plate 50) and the variable angle prism 7
You may arrange between 1.

[Embodiment 7] The polarized illumination device 1 shown in FIG.
At 0G, the arrangement of each optical system is the same as that of the first embodiment, but the prism structure 30G is configured by the six transparent plates 73 that form the wall surface, and the polarization separation film 31 is formed inside thereof. A flat plate-shaped polarization separation plate 74 is arranged, and the liquid 7
It is characterized in that the structure formed by filling 5 is used as the polarized light separating section 30. This makes it possible to reduce the cost and the weight of the polarization splitting unit 30.

[Embodiment 8] The polarized illumination device 1 shown in FIG.
At 0H, the arrangement of each optical system is the same as that of the first embodiment, but is characterized in that the polarization separation section 30 is a flat plate-shaped structure. That is, by arranging the polarization separation plate 74 on which the polarization separation film 31 is formed so as to form an angle of γ = 45 degrees with respect to the system optical axis L ′, the two main prisms shown in FIG. The same function as that of the polarized light separating section 30 is achieved. Thereby, the polarization splitting unit 30
It is possible to reduce cost and weight.

[Embodiment 9] The projection display apparatus (liquid crystal projector) of the present embodiment uses the polarized illumination device of Embodiments 1 to 8 to improve the brightness of the image. FIG. 13 is a schematic configuration diagram of a projection type display device using the polarized illumination device shown in FIG.

In FIG. 13, the projection type display device 8 of this example is shown.
00 includes a polarized illumination device 10A, that is, a light source unit 2 that emits randomly polarized light in one direction.
Random polarized light emitted from the light source unit 20 is split into two types of polarized light in the polarization splitting unit 30, and P polarized light of the split polarized light is Λ / 2 phase difference plate 6 of the condenser lens unit 60
2, the light is converted into S-polarized light.

The luminous flux emitted from the polarized illumination device 10A is first of all a blue-green reflecting dichroic mirror 80.
In No. 1, red light is transmitted and blue light and green light are reflected. The red light is reflected by the reflection mirror 802.
Is reflected by the first liquid crystal light valve 803 and reaches the first liquid crystal light valve 803.
On the other hand, of the blue light and the green light, the green light is reflected by the green reflective dichroic mirror 804 and reaches the second liquid crystal light valve 805.

Here, the blue light has the longest optical path length among the respective color lights, so that for the blue light, the incident side lens 806, the relay lens 808, and the emission side lens 81.
A light guide unit 850 constituted by a relay lens system of 0 is provided. That is, the blue light is first transmitted through the green reflective dichroic mirror 804, and then, first, the emission side lens 8
06 and the reflection mirror 807, and then the relay lens 8
08, after being focused by the relay lens 808, it is guided by the reflection mirror 809 to the emission side lens 810, and then reaches the third liquid crystal light valve 811. Here, the first and third liquid crystal light valves 80
Reference numerals 3, 805 and 811 modulate respective color lights to include image information corresponding to the respective colors, and then the modulated color lights are incident on the dichroic prism 813 (color combining means).
The dichroic prism 813 has a red-reflecting dielectric multilayer film and a blue-reflecting dielectric multilayer film in a cross shape, and synthesizes the respective modulated light beams. The light fluxes combined here pass through the projection lens 814 (projection means) and form an image on the screen 815.

Projection type display device 800 having such a configuration
In, a liquid crystal light valve of the type that modulates one type of polarized light is used. Therefore, when random polarized light is guided to the liquid crystal light valve using the conventional lighting device, half of the randomly polarized light is absorbed by the polarizing plate and converted into heat, resulting in low light utilization efficiency. At the same time, there is a problem that a cooling device that suppresses the heat generation of the polarizing plate and that is large in noise is required. However, in the projection display apparatus 800 of this example, such a problem is largely solved.

That is, in the projection type display device 800 of this example, in the polarized illumination device 10A, only one polarized light (for example, P polarized light) is rotated by the λ / 2 retardation plate 62. To make the polarization plane aligned with the other polarized light (for example, S-polarized light). Therefore, the polarized light whose polarization direction is uniform is guided to the first to third liquid crystal light valves 803, 805, 811, so that the light utilization efficiency is improved and a bright projected image can be obtained. Further, since the amount of light absorbed by the polarizing plate is reduced, the temperature rise in the polarizing plate is suppressed. Therefore, downsizing and noise reduction of the cooling device can be realized. Moreover, the polarized illumination device 10
In A, since a thermally stable dielectric multilayer film is used as the polarization separation film, the polarization separation performance of the polarization separation unit 30 is thermally stable. Therefore, the stable polarization separation performance is always exhibited even in the projection display device 800 that requires a large light output.

Further, in the polarized illumination device 10A, since the two types of polarized light emitted from the polarized light separating section 30 are separated in the lateral direction, they have a horizontally long rectangular shape without wasting the light amount. An illuminated area can be formed. Therefore,
The polarized illumination device 10A is suitable for a horizontally long liquid crystal light valve that is easy to see and can project a powerful image.

In addition, in this example, since the dichroic prism 813 is used as the color synthesizing means, the size can be reduced and the liquid crystal light valve 80 can be used.
Since the optical path length between 3, 805, 811 and the projection lens 814 is short, there is a feature that a bright projection image can be realized even if a projection lens having a relatively small diameter is used. Also, each color light has a different optical path length only in one of the three optical paths,
In this example, for blue light having the longest optical path length, the light guide unit 8 configured by a relay lens system including an incident side lens 806, a relay lens 808, and an emission side lens 810.
Since 50 is provided, color difference or the like does not occur.

[Embodiment 10] As the projection type display device, as shown in FIG. 14, a color synthesizing means may be constituted by a mirror optical system. When a mirror optical system is used as the color synthesizing means, liquid crystal light valves 803, 805 at three locations,
Since the optical path lengths of 811 and the light source unit 20 are equal, there is a feature that effective illumination with little brightness unevenness and color unevenness can be performed without using a special light guide means.

That is, referring to FIG. 14, in the projection display device 900 of this example, the polarized illumination device 10A shown in FIG.
Random polarized light emitted from the light source unit 20 is split into two types of polarized light in the polarization splitting unit 30, and among the split polarized lights, the P-polarized light is Λ / 2 phase difference plate 6 of the condenser lens unit 60
2, the light is converted to S-polarized light.

With respect to the light flux emitted from the polarized illumination device 10A, first, red light is reflected by the red reflection dichroic mirror 901, and blue light and green light are transmitted. Here, the red light is reflected by the reflection mirror 9
It is reflected at 02 and reaches the first liquid crystal light valve 803. On the other hand, of the blue light and the green light, the green light is reflected by the green reflective dichroic mirror 903 and reaches the second liquid crystal light valve 805. The blue light reaches the third liquid crystal light valve 811 after passing through the green reflective dichroic mirror 903. Then, the first and third liquid crystal light valves 803, 805, 811 are
Each color light is modulated, and image information corresponding to each color is included, and then the modulated color light is emitted. Here, the intensity-modulated red light is reflected by the green reflection dichroic mirror 904.
Then, the light passes through the blue reflection dichroic mirror 905 and reaches the projection lens 814 (projection unit). The intensity-modulated green light is reflected by the green reflection dichroic mirror 904.
After being reflected by, the light passes through the blue reflection dichroic mirror 905 and reaches the projection lens 814. The intensity-modulated green light is reflected by the green reflective dichroic mirror 904, then passes through the blue reflective dichroic mirror 905, and reaches the projection lens 814. The intensity-modulated blue light reaches the projection lens 814 after being reflected by the blue reflection dichroic mirror 905.

As described above, since the liquid crystal light valve of the type that modulates one kind of polarized light is also used in the projection type display device 900 in which the color synthesizing means is constituted by the mirror optical system including the dichroic mirror, When the randomly polarized light is guided to the liquid crystal light valve by using the illumination device, half of the randomly polarized light is absorbed by the polarizing plate and converted into heat. Therefore, in the conventional lighting device, there is a problem that the efficiency of using light is low and a large-sized and noisy cooling device that suppresses heat generation of the polarizing plate is required. However, in the projection display device 900 of this example, This problem has been largely resolved.

That is, in the projection display apparatus 900 of this example, in the polarized illumination device 10A, only one polarized light (for example, P polarized light) is rotated by the λ / 2 retardation plate 62 to rotate the polarization plane. To make the polarization plane aligned with the other polarized light (for example, S-polarized light). Therefore, the polarized light whose polarization direction is uniform is guided to the first to third liquid crystal light valves 803, 805, 811, so that the light utilization efficiency is improved and a bright projected image can be obtained. Further, since the amount of light absorbed by the polarizing plate is reduced, the temperature rise in the polarizing plate is suppressed. Therefore, downsizing and noise reduction of the cooling device can be realized. Moreover, the polarized illumination device 10
In A, since a thermally stable dielectric multilayer film is used as the polarization separation film, the polarization separation performance of the polarization separation unit 30 is thermally stable. Therefore, a stable polarization separation performance is always exhibited even in the projection display device 900 that requires a large light output.

Other Examples In each of the above examples, the λ / 2 retardation plate and the λ / 4 retardation plate made of a general polymer film are used. The retardation plate may be configured by using 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 of the λ / 2 retardation plate and the λ / 4 retardation plate can be reduced as compared with the case of using a general polymer film. This has the effect of improving conversion performance.

[0066]

As described above, in the polarized light illumination device according to the present invention, one of the polarized lights separated by the polarized light separating section using the dielectric multilayer film, or the polarized light of both polarized lights. Since the retardation layer gives a rotating action of the polarization plane to the light to bring the polarization planes into alignment, it is possible to irradiate polarized light with aligned polarization directions. Therefore, when the polarized illuminating device according to the present invention is used for the projection type display device using the liquid crystal light valve, the polarized light whose polarization planes are aligned can be supplied to the liquid crystal light valve, so that the light utilization efficiency is improved. , It is possible to improve the brightness of the projected image. Further, since the amount of light absorbed by the polarizing plate is reduced, the temperature rise in the polarizing plate is suppressed. Therefore, downsizing and noise reduction of the cooling device can be realized. Moreover, since the thermally stable dielectric multilayer film is used as the polarization separation film, the polarization separation performance of the polarization separation unit is thermally stable. Therefore, a stable polarization separation performance is always exhibited even in a projection display device that requires a large light output.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing the configuration of a polarized light illumination device according to a first embodiment of the invention.

FIG. 2 is an external view showing the configuration of a condenser mirror plate used in the polarized illumination device shown in Embodiment 1 of the present invention.

FIG. 3 is a diagram for explaining a rotation process of a polarization plane by a λ / 4 retardation plate and a condenser mirror plate.

FIG. 4 is a diagram showing a state of forming a secondary light source image formed by two types of polarized light of P-polarized light and S-polarized light in the vicinity of the condenser lens in the polarized illumination device shown in Example 1 of the present invention. Explanatory drawing at the time of seeing from a side toward a polarization separation part.

FIG. 5 is a schematic plan view showing the configuration of the polarized illumination device according to the second embodiment of the invention.

FIG. 6 is a schematic plan view showing the configuration of a polarized lighting device according to a third embodiment of the invention.

FIG. 7 is an external view showing a configuration of a condenser mirror plate used in Examples 3, 5 and 6 of the present invention.

FIG. 8 is a schematic plan view showing the configuration of a polarized lighting device according to a fourth embodiment of the invention.

FIG. 9 is a schematic plan view showing the configuration of a polarized lighting device according to a fifth embodiment of the invention.

FIG. 10 is a schematic plan view showing the configuration of a polarized lighting device according to a sixth embodiment of the present invention.

FIG. 11 is a schematic plan view showing the configuration of the polarized illumination device according to the seventh embodiment of the present invention.

FIG. 12 is a schematic plan view showing the configuration of a polarized lighting device according to an eighth embodiment of the present invention.

FIG. 13 is a schematic plan view showing the configuration of a projection display apparatus according to Embodiment 9 of the present invention.

FIG. 14 is a schematic plan view showing the configuration of the projection display apparatus according to Embodiment 10 of the present invention.

15A is a schematic plan view showing the configuration of a conventional polarized illumination device, and FIG. 15B is an external view showing the configuration of a condenser lens plate.

[Explanation of symbols]

10A to 10H ... Polarized illumination device 20 ... Light source 21 ... Light source lamp 22 ... Parabolic reflector 30 ... Polarization separation unit 30G ... Prism structure 301 ... Incident surface 302 ... ..First exit surface 303 ... Second exit surface 304 ... Third exit surface 31 ... Polarization separation film 32 ... Right-angle prism 33 ... First λ / 4 phase difference Plate 331 ... λ / 4 retardation plate 332 ... Mirror plate 333 ... P-polarized light 334 ... S-polarized light 335 ... Clockwise circularly polarized light 336 ... Counterclockwise circularly polarized light Light 34 ... Second λ / 4 retardation plate 40 ... First condensing mirror plate 41 ... Micro condensing mirror 42 ... Reflecting surface 50 ... Second condensing mirror plate 60 ... Condensing lens part 61 ... Condensing lens plate 611 ... Micro lens 62 ... λ / Retardation plate 621 ... λ / 2 retardation layer 70 ... Illumination area 71 ... Deflection prism 72 ... Condensing mirror plate 721 ... Incident surface 722 ... Glass block 723 ... -Reflecting surface 73 ... Transparent plate 74 ... Polarization separating plate 75 ... Liquid 800 ... Projection display device (dichroic prism type) 801 ... Blue-green reflection dichroic mirror 802 ... Reflection mirror 803・ ・ ・ First liquid crystal light valve 804 ・ ・ ・ Green reflective dichroic mirror 805 ・ ・ ・ Second liquid crystal light valve 806 ・ ・ ・ Incoming side lenses 807, 809 ・ ・ ・ Reflecting mirror 808 ・ ・ ・ Relay lens 810 ・..Emitting side lens 811, 3rd liquid crystal light valve 813, dichroic prism 814, projection lens 815, screen 850 ... Light guide means 900 ... Projection display device (mirror optical system) 901 ... Red reflection dichroic mirror 902 ... Reflection mirrors 903, 904 ... Green reflection dichroic mirror 905 ... Blue reflection Dichroic mirror 981 ... First lens plate 982 ... Polarization separation means 983 ... Second lens plate 984 ... .lambda. / 2 phase difference plate 985 ... Rectangular lens 986 ... Light source unit 988 ... Illumination area 989 ... Integrator optical system

Claims (13)

[Claims] 1. A structure in which a light source section for emitting polarized light having a random polarization direction and a polarization separation film made of a dielectric multilayer film are sandwiched between two right-angle prisms, and the polarization separation film is used to separate the light source section from the light source section. It is composed of a polarization splitting unit that splits the emitted polarized light into two polarized lights of P-polarized light and S-polarized light whose polarization directions are orthogonal to each other and emits the polarized light, and a plurality of minute condenser mirrors having a rectangular outer shape. A first condensing mirror plate for condensing the P-polarized light emitted from the polarization splitting unit and forming a plurality of secondary light source images of the P-polarized light; and the first condensing mirror plate. It has almost the same dimensions and shape as
The S-polarized light emitted from the polarization splitting unit is condensed, and a plurality of S-polarized light beams are formed at positions slightly different from the positions at which the plurality of P-polarized light secondary light source images are formed.
A second light collecting mirror plate for forming a secondary light source image; a space between the first light collecting mirror plate and the polarization separation unit; and a second light collection mirror plate and the polarization separation unit. And a first λ / 4 retardation plate and a second λ /
A four-phase retarder, a plurality of secondary light source images composed of the P-polarized light and a plurality of secondary light source images composed of the S-polarized light are arranged in the vicinity of the position, and the first or second collection plate is formed. A polarized light illuminating device, comprising: a condenser lens plate composed of the same number of minute lenses as the minute condenser mirrors constituting the optical mirror plate, and a condenser lens portion composed of a λ / 2 phase difference plate. 2. The polarized light illumination device according to claim 1, wherein a variable angle prism is arranged between the light source unit and the polarized light separating unit. 3. The divergence angle according to claim 1, between the polarization separation section and the first condenser mirror plate, and between the polarization separation section and the second condenser mirror plate. A polarized light illuminating device comprising a prism. 4. The polarized illumination device according to claim 2 or 3, wherein the variable angle prism is integrated with the polarized light separating unit. 5. The polarized illumination device according to claim 3, wherein the variable angle prism is integrated with the first condenser mirror plate and the second condenser mirror plate. 6. The deflecting prism according to claim 3, wherein the deflection prism is integrated with the polarization splitting section, the first condenser mirror plate, and the second condenser mirror plate. Polarized illumination device. 7. The polarized light separating unit according to claim 1,
A polarized illuminating device comprising a flat polarization separating plate. 8. The polarized illumination device according to claim 1, wherein the right-angled prism forming the polarized light separating section is a liquid-filled prism. 9. The polarized illumination device according to claim 1, wherein the λ / 2 retardation plate and the λ / 4 retardation plate are made of TN (twisted nematic) liquid crystal. 10. The separation direction of the two types of secondary light source images formed by the two condensing mirror plates is the same as the longitudinal direction of the illumination area according to any one of claims 1 to 9. A polarized lighting device characterized by the above. 11. The polarized illumination device according to claim 1, wherein in the condenser lens plate, the minute lenses have a shape similar to that of the minute condenser mirror. 12. A structure in which a light source section for emitting polarized light having a random polarization direction and a polarization separation film made of a dielectric multilayer film are sandwiched between two right-angle prisms, and the polarization separation film is used to separate the light source section from the light source section. It is composed of a polarization splitting unit that splits the emitted polarized light into two polarized lights of P-polarized light and S-polarized light whose polarization directions are orthogonal to each other and emits the polarized light, and a plurality of minute condenser mirrors having a rectangular outer shape. A first condensing mirror plate for condensing the P-polarized light emitted from the polarization splitting unit and forming a plurality of secondary light source images of the P-polarized light; and the first condensing mirror plate. It has almost the same dimensions and shape as
The S-polarized light emitted from the polarization splitting unit is condensed, and a plurality of S-polarized light beams are formed at positions slightly different from the positions at which the plurality of P-polarized light secondary light source images are formed.
A second light collecting mirror plate for forming a secondary light source image; a space between the first light collecting mirror plate and the polarization separation unit; and a second light collection mirror plate and the polarization separation unit. And a first λ / 4 retardation plate and a second λ /
A four-phase retarder, a plurality of secondary light source images composed of the P-polarized light and a plurality of secondary light source images composed of the S-polarized light are arranged in the vicinity of the position, and the first or second collection plate is formed. A condenser lens part composed of a condenser lens plate composed of the same number of minute lenses as the minute mirror mirror constituting the optical mirror plate and a λ / 2 phase difference plate, and light passing through the λ / 2 phase difference plate. Of the three primary colors, three light valves for respectively modulating each color light based on an image signal from the outside, and the modulated light of each color light modulated by the light valve are combined. A projection display device comprising: a color synthesizing unit configured to perform the color synthesizing; and a light projecting unit configured to project each color light synthesized by the color synthesizing unit onto a screen. 13. The color synthesizing means according to claim 12, wherein the color synthesizing means has a dichroic prism, and among the optical paths of the respective color lights from the color separating means to the respective light valves, the optical path having the longest optical path length is guided. A projection display device characterized by having a light means.