JP2000305045A - Picture projection device and picture observation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture projection device being suitable for a liquid crystal projector having high utilizing efficiency of light. SOLUTION: This picture projection device is provided with a color separation system 5 separating a light beam emitted from a lamp unit 101 to the plural color light beam, plural liquid crystal panels 9 modulating the respective color light beams R, G and B separated by the separation system 5 based on an image signal, a color synthesis system DP synthesizing the color light beams emitted from the respective panels 9 to one light beam and a projection lens 12 projecting the light beam synthesized by the synthesis system DP on a screen 13. Then, the synthesis system DP is composed of a cross dichroic prism obtained by forming a dichroic film at the sticking surfaces of four prisms and the respective beams R, G and B made incident on the cross dichroic prism are the straight-line polarized light beams. When an angle formed by the polarizing direction of a color light component transmitted through all the dichroic films and that of the color light component reflected on the dichroic films once is defined as θ, the expression of 0 deg.<θ<90 deg. is satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for projecting an image and an apparatus for observing an image. More particularly, the present invention uses a liquid crystal display element (liquid crystal panel) as an image display element and projects an image obtained by the projection lens, The present invention is suitable for a liquid crystal projector that projects onto a polarizing screen, and an image observation system in which images of a computer screen or a video camera can be enlarged and observed.

[0002]

2. Description of the Related Art Conventionally, an image is displayed using a liquid crystal panel by illuminating the liquid crystal panel with a light beam from a light source, and an image based on transmitted or reflected light from the liquid crystal panel is enlarged and projected on a screen by a projection lens. Various image projection apparatuses (liquid crystal projectors) have been proposed.

FIG. 17 is a schematic view of a main part of a conventional image projection apparatus. In FIG. 17, reference numeral 101 denotes a white light source.
102 is a reflector. Reference numeral 103 denotes a visible light transmitting filter that removes light components other than visible light.

An integrator 104 for obtaining a uniform illumination area is composed of fly-eye lenses 104a and 104b, each of which comprises a plurality of lens arrays. Reference numeral 105 denotes a polarization conversion element array that converts non-polarized light into linearly polarized light that is polarized in a predetermined polarization direction.
Polarization separation surface 105a, reflection surface 105b, and 1/2 phase plate 1
05c.

Reference numeral 106 denotes a condenser lens. 107 is the first
Are dichroic mirrors DM1, 108, and second dichroic mirrors DM2, 109a, 109b are reflection mirrors. Reference numeral 110 denotes a relay system for relaying illumination light, and includes relay lenses 110a and 110b and a relay mirror 1
10c and 110d.

Reference numerals 111r, 111g, and 111b denote condenser lenses for images (light) of R (Red), G (Green), and B (Blue) colors, respectively. 112
r, 112g, and 112b are image display elements for R, G, and B, respectively. Reference numeral 113 denotes a cross dichroic prism DP for color synthesis. 114 is a projection lens.

The white light emitted from the white light source 101 is
The light is condensed by the reflector 102, the integrator 104, the polarization conversion element array 105, and the condensing lens 10
After passing through No. 6, dichroic mirrors 107 and 108
By the first color light (B in the figure).
Is guided to the image display element 112b via the reflection mirror 109b and the condenser lens 111b, and the second color light (G in the figure) is guided to the image display element 112g via the condenser lens 111g and becomes the third color light (R in the figure). Is the relay system 11
0 and the image display element 1 via the condenser lens 111r
It is led to 12r.

The image display elements 112b, 112g,
The light of each color transmitted through 112r and modulated in accordance with the image signal is combined with the R, G, and B color lights by the cross dichroic prism DP113 to form the projection lens 1
By 14, the images displayed by the respective image display elements are superimposed and projected on a screen (not shown). As a white light source, a discharge lamp such as a metal halide lamp or a mercury lamp is used.

FIG. 18 shows an example of the spectral distribution of the white light source 101. From white light having a continuous spectral distribution as described above, for example, by dichroic mirrors DM1 and DM2, for example,
R and G, each having a spectral distribution as shown in FIG.
Three color lights of B are generated.

Conventionally, these lights are modulated by the image display elements 112r, 112g, and 112b, respectively, and then synthesized by the cross dichroic prism DP. In order to eliminate the loss of light amount in the cross dichroic prism DP, the cross dichroic prism is used. Are reflected as red (R) and blue (B) S-polarized light components, and green (G) light transmitted through the dichroic film of the cross dichroic prism DP is referred to as a P-polarized light component.

This is because, as shown in FIG. 20, when the dichroic film is reflected, the reflection band of the S-polarized light component can be set wider than that of the dichroic film (BRs, RR).
s), when transmitting through the dichroic film, the P-polarized light component can set a wider transmission band (GTp). This is the change in the cut wavelength of the dichroic film due to the change in the incident angle of the light beam to the dichroic film.
The loss of light quantity at the dichroic prism due to the so-called incident angle characteristic of the dichroic film is suppressed.

In order to realize such a configuration, when the polarization direction of the image light emitted from the image display element is as shown in FIG. 21, a 1/2 phase plate is provided for each of the three emission optical paths.
The slow axis direction of the phase plate is set so that the G polarization direction is orthogonal to the R and B polarization directions, and the G polarization direction is P-polarized light with respect to the dichroic film of the dichroic prism DP. Was.

[0013]

However, when an image is projected, it is necessary to align the directions of polarization of the projected light (for example, a polarized image projection system using a polarizing screen, a polarized image projection system using light having different polarization directions from each other). In a stereoscopic image projection system that projects images for the right and left eyes, a polarizing means is provided at an arbitrary position in an optical path from a dichroic prism to a polarizing screen or an observer, and the polarization direction of G and the polarization of R and B are provided. They have to be aligned.

This is because green light is absorbed when the polarization direction of the light reflected by the polarizing screen is set parallel to the S-polarized light component of the dichroic prism.
This is because when the polarization direction of the light reflected by the polarizing screen is set in parallel with the P-polarized light component of the dichroic prism, red and blue color lights are absorbed and a correct color image cannot be reproduced.

Therefore, for example, as shown in FIG. 22, the polarization direction SC of the screen is converted into a polarization direction inclined by 45 degrees with a half-wave plate, or as shown in FIG.
It is conceivable to convert each polarized light into a circularly polarized light by using a / 4 wavelength plate.

However, in such a use method, the intensity of the projected light becomes cos ² (45) = 0.5 due to the absorption of the polarizing plate on the polarizing screen, and another problem that the brightness of the projected image is reduced by half. Is generated, and the configuration is not suitable for an image projection system that aligns polarized light.

If the polarization directions of the respective color lights incident on the dichroic prism are aligned in advance, the loss of brightness in the polarizing screen can be almost eliminated. However, as shown in FIG. Becomes narrower, and the margin for the wavelength component of each color light transmitted or reflected by the dichroic prism decreases, and the loss of the light amount due to the incident angle characteristic of the dichroic film increases.

An object of the present invention is to provide a projection device and an image observation device capable of improving the light use efficiency as compared with the related art.

[0019]

A first aspect of the present invention provides a means for supplying light, a color separation system for separating the light from the means into a plurality of color lights, and each color separated by the color separation system. It has a plurality of light modulating elements for modulating light based on image signals, a color synthesizing system for synthesizing color lights emitted from the respective light modulating elements, and a projection optical system for projecting the light synthesized by the color synthesizing systems. In the projection device, the color combining system has a plurality of dichroic films, and the color lights incident on the dichroic films are respectively linearly polarized light, and the polarization direction of the color light transmitted through all the dichroic films and reflected by the dichroic film. An image projection apparatus characterized by satisfying 0 ° <θ <90 ° when an angle between polarization directions of colored light is θ.

According to a second aspect of the present invention, there is provided means for supplying light,
A color separation system for separating the light from the means into a plurality of color lights;
A plurality of light modulation elements for modulating each color light separated by the color separation system based on an image signal; a color synthesis system for synthesizing color light emitted from each light modulation element; and a light synthesized by the color synthesis system. In a projection apparatus having a projection optical system for projecting light on a polarizing screen, the color synthesizing system has a plurality of dichroic films, and color light incident on the dichroic films is linearly polarized light, and all of the dichroic films pass through the dichroic films. When the angle between the polarization direction of the color light to be reflected and the polarization direction of the color light reflected by the dichroic film is θ, 0 ° <θ <90 ° is satisfied, and 1 ° is present in the optical path from the color synthesis system to the polarizing screen. / 2 phase plate is disposed, and the angle between the polarization direction of the color light transmitted through the dichroic film and the transmitted polarization direction of the polarizing screen is equal to the angle of the color light reflected by the dichroic film. An image projection apparatus, wherein an angle between a polarization direction and a transmission polarization direction of the polarizing screen is substantially equal.

According to a third aspect of the present invention, there is provided the image projection apparatus according to the second aspect, wherein the half-phase plate is provided at an emission portion of a projection lens of the projection optical system.

The invention according to claim 4 is the image projection apparatus according to claim 2, wherein the 1/2 phase plate is provided between the color synthesizing means and the projection lens of the projection optical system.

The invention according to claim 5 is the image projection apparatus according to claim 2, wherein the slow axis of the half-phase plate rotates around the optical axis of the projection optical system. is there.

According to a sixth aspect of the present invention, there is provided means for supplying a plurality of color lights, a plurality of light modulation elements for modulating each of the color lights based on an image signal, and a color synthesis for synthesizing the color lights emitted from each of the light modulation elements. System, and a projection apparatus having a projection optical system for projecting light synthesized by the color synthesis system, wherein each color light incident on the dichroic film of the color synthesis system is linearly polarized light, and is transmitted through the dichroic film. An image projection apparatus characterized by satisfying 0 ° <θ <90 ° when an angle between the polarization direction of the color light to be emitted and the polarization direction of the color light reflected by the dichroic film is θ.

According to a seventh aspect of the present invention, the polarization direction of the color light component reflected by the dichroic film is S with respect to the dichroic film.
7. The image projection device according to claim 1, wherein the image projection device is polarized light.

The invention according to claim 8 is the image projection apparatus according to claim 1, wherein the angle θ satisfies 0 ° <θ <80 °.

According to a ninth aspect of the present invention, there is provided the image projection apparatus according to any one of the first to sixth aspects, wherein the angle θ satisfies 0 ° <θ <60 °.

According to a tenth aspect of the present invention, there is provided the image projection apparatus according to the first, second or sixth aspect, wherein the angle θ satisfies 0 ° <θ <45 °.

An eleventh aspect of the present invention is the image projection apparatus of the first, second or sixth aspect, wherein the angle θ is θ = 45 °.

In a twelfth aspect of the present invention, the observer wears polarized glasses for selectively inputting light having different polarization states to the left and right eyes, and places the polarized light on the polarizing screen for preserving the polarization direction by the first and second projection devices. In an image observation apparatus for observing a stereoscopic image from a projected parallax image, the first and second image projection apparatuses each include a unit for supplying light and a unit for separating the light from the unit into a plurality of color lights. A color separation system, a plurality of light modulation elements for modulating the respective color lights based on image signals, a synthesis system having a plurality of dichroic films for synthesizing the color lights emitted from the respective light modulation elements, and synthesis by the color synthesis system. A projection optical system for projecting the divided light onto the polarizing screen, and a polarization direction of the color light that passes through the dichroic film and the dichroic film, which are arranged in an optical path to the color combining system and the polarizing screen. A polarizing plate whose polarization axis is oriented in a direction that bisects the angle formed by the polarization directions of the color lights reflected by the
The color light incident on the dichroic film is a linearly polarized light, and the angle between the polarization direction of the color light component transmitted through the dichroic film and the polarization direction of the color light component reflected by the dichroic film is 0 °. <Θ <90 °, and a phase plate capable of changing a polarization state of light is provided at a light emission position of at least one of the first and second image projection devices, 2 above
An image observation apparatus characterized in that the polarization states of light projected by the two projection apparatuses are different.

13. An image observation apparatus according to claim 12, wherein said angle θ satisfies 0 ° <θ <80 °.

14. An image observation apparatus according to claim 12, wherein said angle θ satisfies 0 ° <θ <60 °.

15. An image observation apparatus according to claim 12, wherein said angle θ satisfies 0 ° <θ <45 °.

16. An image observation apparatus according to claim 12, wherein said angle θ is θ = 45 °.

According to a seventeenth aspect of the present invention, there is provided a system for projecting an image created by a computer using the image projection device according to any one of the first to eleventh aspects.

The invention according to claim 18 is the image projection apparatus according to claim 1, wherein the angle θ is 80 degrees.

According to a nineteenth aspect, in the image observation apparatus according to the twelfth aspect, the angle θ is 80 degrees.

According to a twentieth aspect of the present invention, there is provided the image projection apparatus according to the sixth aspect, wherein the light emitting portion of the projection optical system has a half-wave plate.

The invention according to claim 21 is the image projection apparatus according to claim 6, wherein a half-wave plate is provided between said projection optical system and said color synthesizing system.

The invention according to claim 22, wherein the slow axis of said half-wave plate is rotatable around the optical axis of said projection optical system. It is.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part of a first embodiment of the present invention. In the figure, reference numeral 101 denotes a light source (lamp) such as a metal halide lamp or a mercury lamp. Reference numeral 102 denotes a reflector having a paraboloid or an ellipsoid.

Reference numeral 103 denotes a fly-eye lens type integrator including a first lens array 103a and a second lens array 103b. 4 is a plurality of polarized light separating surfaces 4a
And a polarization conversion element array including a plurality of reflection surfaces 4b corresponding to the polarization separation surfaces 4a and a plurality of phase plates 4c. Reference numeral 5 denotes a color separation system including dichroic mirrors 51 and 52.

Reference numerals 71 and 72 are mirrors. Reference numeral 8 denotes a relay system having condensing mirrors 81, 82, 83 and mirrors 84, 85. Reference numerals 1r, 1g, and 1b denote image display elements for red, green, and blue using liquid crystal. 2r, 2
g and 2b denote polarizing plates for detecting light from the image display elements 1r, 1g and 1b as analyzers, and 3r and 3b denote 位相 phases for converting the polarization directions of the light fluxes of the R light path and the B light path. It is a board. DP is a cross dichroic prism as a color synthesis system.

Reference numeral 12 denotes a projection lens having a positive refractive power for magnifying and projecting an image displayed by each image display element. Reference numeral 6 denotes a condenser lens for condensing diffused light from the polarization conversion element array 4 on the image display element.

Reference numerals 9G and 9B denote illumination lenses for projecting lens 12 respectively.
This is a condenser lens for collecting light.

The optical path shown in FIG. 1 will be described. Light source 101
Part of the light beam from the first lens array 1
03a, and the other light flux is reflected by the reflector 102 and enters the first lens array 103a. These light beams form a plurality of secondary light source images near the second lens array 103b by the first lens array 103a.

Each light beam from a plurality of secondary light source images near the second lens array 103b enters the corresponding polarization conversion element. Then, the light is incident on the condenser lens 6 as a light beam (S-polarized light) whose polarization direction is aligned by the polarization conversion element array 4.

Light beams from a plurality of secondary light source images formed in the vicinity of the second lens array 103b are passed through a condenser lens 6 and a condenser lens 9B (9G, relay system 8) to form an image display element as a surface to be irradiated. 1b (1g, 1r) is superimposed on and illuminates it.

Here, the white light from the condenser lens 6 is reflected by the mirror 71 and is incident on the dichroic mirror 51. The blue light is transmitted by the dichroic mirror 51, reflected by the mirror 7, condensed by the condenser lens 9B, and illuminates the image display element 1b for blue.

Of the green light and the red light reflected by the dichroic mirror 51, the green light is reflected by the dichroic mirror 52 and the red light is transmitted.

The green light reflected by the dichroic mirror 52 is condensed by the condenser lens 9G to illuminate the green image display element 1g.

The red light transmitted through the dichroic mirror 52 is collected by the relay system 8 and illuminates the red image display element 1r. The images of the respective color lights from the image display elements 1b, 1g, and 1r are shown in the enlarged view of FIG.
After passing through a / 2 phase plate 3), they are combined by a cross dichroic prism DP (hereinafter, referred to as a dichroic prism DP). Then, the light is enlarged and projected on the polarizing screen 13 by the projection lens 12 via the 1/2 phase plate 34.

As shown in the enlarged view of FIG. 2, the polarization conversion element array 4 has an incident light L on a polarization separation surface 4a provided with a polarization separation film.
Of I, P-polarized light is transmitted and S-polarized light is reflected. Among them, the P-polarized light that has passed through the polarization separation surface 4a is 1
After passing through the half-wave plate 4c, the polarization direction is changed by 90 degrees and S
The light becomes polarized light and exits.

On the other hand, the S-polarized light reflected on the polarization separation surface 4a is reflected on the reflection surface 4b and exits from the exit surface 4d. Thus, the polarization conversion element array 4 emits the incident light as a linearly polarized light beam of S-polarized light.

FIG. 3 is an enlarged view showing a main part near the cross dichroic prism DP according to the first embodiment of the present invention.

FIG. 3 shows a configuration from the image display elements 1r, 1g, 1b to the dichroic prism DP. In FIG. 3, 1r, 1g, and 1b are image display elements for red (R), green (G), and blue (B), respectively, and 2r, 2g, and 2b are analyzers for light from the image display element. Is a polarizing plate.

Reference numerals 3r and 3b denote 1/2 phase plates for converting the polarization directions of the light beams in the R light path and the B light path.

FIG. 4 shows the directions of polarized light in the respective optical elements used in this embodiment. In the image display elements 1r, 1g, and 1b, the polarization direction of the image light indicated by the arrow in the drawing is at 45 degrees with respect to the direction of the S-polarized component (polarized light perpendicular to the paper surface) of the dichroic film of the dichroic prism. In the polarizing plates 2r, 2g, and 2r, the transmission polarization directions indicated by arrows in the figure are set parallel (0 degrees) to the polarization direction of the image light of the image display device.
In 3g, the direction of the dotted line in the figure is the slow axis direction, and this direction is set at 22.5 degrees with respect to the direction of the S-polarized light component of the dichroic film of the dichroic prism.

Thus, the polarization directions of R and B are converted into the S-polarized light component of the dichroic film of the dichroic prism DP, and then are incident on the dichroic prism DP. The polarization direction of G is 45 ° with respect to the S-polarized light component of the dichroic film because it enters the dichroic prism with the polarization direction exiting from the image display element 1g. Therefore, the polarization direction of light passing through all of the dichroic film and the dichroic film Once, the angle formed by the polarization direction of the reflected light is 45 degrees.

FIG. 5 shows a portion from the cross dichroic prism DP to the polarizing screen 13 according to the first embodiment of the present invention. In FIG. 5, DP is a cross dichroic prism (dichroic prism), 34 is a 1/2 phase plate for converting the polarization direction of light combined by the prism DP, 12 is a projection lens, and 13 is a polarizing screen.

In this embodiment, the polarization directions of the R and B lights exiting the dichroic prism DP are S-polarized with respect to the dichroic film of the dichroic prism DP. The polarization direction of the light is inclined 45 degrees with respect to the polarization directions of the R and B lights.

FIG. 6 shows the relationship between the direction of the slow axis of the 1/2 phase plate 34 and the direction of the transmitted polarization of the polarizing screen 13 with respect to the direction of polarization of the projection light.

In FIG. 6, the slow axis direction (dotted line) of the 1/2 phase plate 34 is set at an angle of 11.25 degrees with respect to the S polarization direction in the dichroic film of the dichroic prism. The light of the three colors R, G, and B from the prism DP, after passing through the half-phase plate 34, is a light having a polarization direction inclined by 22.5 degrees with respect to the S polarization direction in the dichroic film of the dichroic prism DP. And the transmission polarization direction of the polarizing screen 13 is set parallel to the S-polarization direction of the dichroic film of the dichroic prism. Therefore, the ratio of light that is not absorbed by the screen 13 and can be used for observation is expressed as cos ² (22. 5) = 0.853.

As a result, 85.3% of the projected light can be transmitted through the polarizing screen 13 and used.

In the present embodiment, the light utilization efficiency is reduced by 5%.
This is greatly improved compared to 0%. The position of the 1/2 phase plate 34 may be anywhere between the dichroic prism DP and the polarizing screen 13, and is provided on the exit side of the projection lens 12 as shown in FIG. May be.

As described above, according to the present embodiment, the polarization direction of the color light component that passes through all the dichroic films of the cross dichroic prism and the dichroic film of the cross dichroic prism in the color light incident on the cross dichroic prism for color synthesis. By setting the angle between the polarization directions of the color light components that are once reflected to 45 °, which is smaller than 90 °, the loss of the light amount when the polarization direction is aligned and used is suppressed.

At this time, the polarization direction of the color light component once reflected by the dichroic film is S direction with respect to the dichroic film.
The S-polarized light component is set to have an angle of more than 0 degree and less than 90 degrees with respect to the S-polarized light, so that the loss of light amount due to the incident angle characteristic of the dichroic film is reduced for each color. The polarization direction can be suppressed more than when the polarization directions are aligned, and even in a system not using a polarizing screen, loss of the light amount in the dichroic film can be suppressed to a small extent.

Further, the color light transmitted through the dichroic film is denoted by G, and the color light reflected by the dichroic film is denoted by R and B.
Then, the loss of the light amount in the dichroic film may be small. If the angle between the two polarization components is 80 degrees or less, the light amount increases by 17% or more. If the angle is 60 degrees or less, the light amount increases by 50% or more. More preferably, if the angle is 45 degrees or less, 70%. It is more desirable because the above is improved.

FIG. 8 is a schematic view showing a main part of a part of the second embodiment of the present invention. FIG. 8 shows image display elements 11r, 11b,
The configuration from 11 g to the dichroic prism DP is shown.

In FIG. 8, reference numerals 11r, 11g and 11b denote image display elements for red (R), green (G) and blue (B). Reference numerals 12r, 12g, and 12b denote polarizing plates as analyzers for light from the image display device.

Reference numerals 13r, 13g, and 13b denote 1/2 phase plates on which light paths of R, G, and B are placed, for converting the polarization direction of the corresponding color light.

FIG. 9 shows the directions related to the polarized light in the respective optical elements used in the present embodiment. Image display device 1
In 1r, 11g, and 11b, the polarization direction of the image light indicated by the arrow in the drawing is at 45 degrees with respect to the direction of the S-polarized light component of the dichroic film of the dichroic prism DP, and in the polarizing plates 12r, 12g, and 12b, The transmission polarization direction indicated by the middle arrow direction is parallel (0 degree) to the polarization direction of the image light of the image display device, and the phase plates 13r, 13g, 1
In FIG. 3b, the direction of the dotted line in the drawing is the slow axis direction, and the phase plates 13r, 1 of the optical paths of the R and B colors with respect to the direction of the S-polarized light component of the dichroic film of the dichroic prism DP.
3b is set at 22.5 degrees, and the phase plate 13 of the optical path G is set.
g is set at 50 degrees.

As a result, the polarization directions of R and B are converted into the S-polarized light component of the dichroic film of the dichroic prism DP, and then are incident on the dichroic prism DP.

On the other hand, the polarization direction of G is set so as to be converted into a polarization direction at an angle of 55 degrees with respect to the S-polarized light component of the dichroic film of the dichroic prism DP and to be incident on the dichroic prism. Thereby, the same effect as in the first embodiment is obtained.

FIG. 10 is a schematic view of a main part of a part of the third embodiment of the present invention. FIG. 10 shows image display elements 21r and 21r.
2 shows the configuration from g, 21b to the dichroic prism DP.

In FIG. 10, reference numerals 21r, 21g and 21b denote image display elements for red (R), green (G) and blue (B). Reference numerals 22r, 22g, and 22b denote polarizing plates as analyzers for light from the image display device.

Reference numeral 23g denotes a 1/2 phase plate placed in the G optical path for converting the polarization direction of the G light. FIG. 11 shows directions of polarized light in the respective optical elements used in the third embodiment. In each image display element 2, the direction of the arrow in the drawing is the polarization direction of the image light, and this direction is parallel to the direction of the S-polarized component of the dichroic prism DP. In the polarizing plates 22r, 22b, and 22g, the direction of the arrow in the figure is the transmission polarization direction, and this direction is set parallel (0 degree) to the polarization direction of the image light of the image display element.
In the phase plate 23g, the direction of the dotted line in the figure is the slow axis direction,
This direction is set at 30 degrees with respect to the direction of the S-polarized light component of the dichroic prism DP.

As a result, the polarization directions of the R and B lights are incident on the dichroic prism DP while being parallel to the S-polarized light component of the dichroic film of the dichroic prism DP. The polarization direction of the G light is changed by the phase plate 23g, and the angle between the polarization direction of the G light that passes through the entire dichroic film and the polarization direction of the R and B light that reflects the dichroic film once is 60 degrees. It is set at the time. Thereby, the same effect as in the first embodiment is obtained.

FIG. 12 is a schematic view showing a main part of a part of the fourth embodiment of the present invention. In FIG. 12, DP is a dichroic prism, and 44 is a 1/2 phase plate for changing the polarization direction of the combined light. 45 is a projection lens. 4
Reference numeral 6 denotes a polarizing screen.

The present embodiment also has the configuration as shown in the first to third embodiments, that is, R, B, which reflects the dichroic prism DP once by the dichroic film and emits it.
The polarization direction of the light is S-polarized light with respect to the dichroic film of the dichroic prism DP.
The polarization direction of the light is inclined by 45 °, which is larger than 0 degree and smaller than 90 degrees with respect to the polarization directions of the R and B lights. FIG. 13 shows the relationship between the direction of the slow axis of the 位相 phase plate 44 and the direction of the transmitted polarization of the polarizing screen 46 with respect to the polarization direction of the projection light in the fourth embodiment.

In FIG. 13, the direction of the slow axis of the 1/2 phase plate 44 is indicated by a dotted line, and the dichroic prism D
56.25 with respect to the S polarization direction in the P dichroic film
The angle is set in degrees. Therefore, the light transmitted through the 位相 phase plate 44 is 22.5 light with respect to the P polarization direction in the dichroic film of the dichroic prism DP.
The light is converted into light having a polarization direction inclined at an angle. Polarizing screen 4
6 is set perpendicular to the S-polarization direction in the dichroic film of the dichroic prism DP, the ratio of light that can be used for observation without being absorbed by the screen 46 is cos ² (22.5) = 0. 853.

As a result, 85.3% of the projected light can be transmitted through the polarizing screen and used.

In the first and fourth embodiments, the phase plate may not be fixed, and may be configured to be rotatable about a direction parallel to the optical axis of the projection lens as a rotation axis. According to this, it is possible to convert the polarization direction of the light to be projected into an optimum state regardless of the transmission polarization direction of the polarization screen.

Next, a fifth embodiment as an image observation apparatus of the present invention will be described. As a system for observing a stereoscopic image using an image projection device, two image projection devices PJ are used.
Using PJ1 and PJ2, PJ1 and PJ2 respectively project an enlarged image of a right-eye image and a left-eye image (or a left-eye image and a right-eye image) onto a screen Sc having characteristics of preserving a polarization state,
A stereoscopic image projection system for observing the image with polarized glasses provided with polarizing plates of polarization components orthogonal to the left and right eyes is generally used. The present embodiment relates to such a system.

FIG. 14 is a schematic diagram of a main part of a stereoscopic image projection system according to Embodiment 5 of the present invention. In FIG. 14, the image projection devices PJ1 and PJ2 each have a color synthesis system having the configuration shown in the first to fourth embodiments, and the polarization directions of the R and B lights emitted from the dichroic prism are relative to the dichroic film of the dichroic prism. The polarization direction of the G light is 4 degrees which is larger than 0 degree and smaller than 90 degrees with respect to the polarization directions of the R and B lights.
The configuration is inclined by 5 °.

The emission portions of the projection lenses of the image projection devices PJ1 and PJ2 are provided with filters PF1 and PF2 each composed of a 1/2 phase plate and a polarizing plate. 1/2 of the filter PF1 with respect to the polarization direction of the projection light exiting the dichroic prism DP in the image projection device PJ1
FIG. 15 shows the relationship between the slow axis direction of the phase plate and the transmitted polarization direction of the polarizing plate.

In FIG. 15, the slow axis direction of the 位相 phase plate indicated by the dotted line is set at an angle of 11.25 degrees with respect to the S polarization direction in the dichroic film of the dichroic prism DP. The light transmitted through the plate is converted into light having a polarization direction inclined by 22.5 degrees with respect to the S polarization direction in the dichroic film of the dichroic prism DP, whereas the transmitted polarization direction A of the polarizing plate of the filter PF1 is Is set parallel to the S polarization direction in the dichroic film of the dichroic prism DP.
The dichroic prism D in the image projection device PJ2
Filter PF for the polarization direction of the projection light emitting P
FIG. 16 shows the relationship between the slow axis direction of the 21/2 phase plate and the transmitted polarization direction of the polarizing plate.

In FIG. 16, the slow axis direction (dotted line) of the 1/2 phase plate is set at an angle of 56.25 degrees with respect to the S polarization direction in the dichroic film of the dichroic prism DP. After passing through the plate, the light is converted into light having a polarization direction inclined by 22.5 degrees with respect to the P polarization direction in the dichroic film of the dichroic prism DP, whereas the transmission polarization direction A of the polarizing plate of the filter PF2 is changed. The direction is set perpendicular to the S-polarized light direction in the dichroic film of the dichroic prism DP.

Thus, the polarization direction of the light projected by the image projection device PJ1 and the polarization direction of the light projected by the image projection device PJ2 can be set to be orthogonal to each other. By projecting an image on a screen having characteristics that can be observed by observing a polarizing plate having transmission polarization axes perpendicular to each other through polarizing glasses provided for the right eye and the left eye, a parallax image of the right eye and the left eye can be obtained. The parallax image is guided to the left eye, and the stereoscopic image is observed.

Instead of the cross dichroic prism as the color synthesizing means in each of the embodiments described above, two dichroic mirrors are crossed, or a plurality of dichroic mirrors are arranged in parallel to each other like color separating means. And a plurality of prisms as shown in Japanese Patent No. 2505758 can be used.

As an integrator for uniform illumination, a rod-type integrator (light pipe) can also be used.

[0092]

As described above, according to the present invention, a light image can be obtained because the light use efficiency is increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of a first embodiment of the present invention.

FIG. 2 is an enlarged explanatory view of a part of FIG. 1;

FIG. 3 is an enlarged explanatory view of a part of FIG. 1;

FIG. 4 is a diagram illustrating a polarization direction of projection light according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of a part according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a polarization direction of projection light according to the first embodiment of the present invention.

FIG. 7 is a partial modification of the first embodiment of the present invention.

FIG. 8 is a schematic diagram of a main part of a part of Embodiment 2 of the present invention.

FIG. 9 is a diagram illustrating a polarization direction of projection light according to the second embodiment of the present invention.

FIG. 10 is a schematic diagram of a main part of a part of a third embodiment of the present invention.

FIG. 11 is a diagram illustrating a polarization direction of projection light according to a third embodiment of the present invention.

FIG. 12 is a schematic diagram of a main part of a part of the fourth embodiment of the present invention.

FIG. 13 is a diagram illustrating a polarization direction of projection light according to a fourth embodiment of the present invention.

FIG. 14 is a schematic view of a main part of a part of a fifth embodiment of the present invention.

FIG. 15 is a diagram illustrating a polarization direction of projection light according to the third embodiment of the present invention.

FIG. 16 is a diagram illustrating a polarization direction of projection light according to a third embodiment of the present invention.

FIG. 17 illustrates a configuration of a conventional projection device.

FIG. 18 is a diagram illustrating characteristics of a color separation system in a conventional example.

FIG. 19 is a diagram illustrating characteristics of a color separation system in a conventional example.

FIG. 20 is a diagram illustrating characteristics of a color separation system in a conventional example.

FIG. 21 is a diagram illustrating a polarization direction of projection light in a conventional example.

FIG. 22 is a view for explaining the polarization direction of projection light on a polarizing screen in a conventional example.

FIG. 23 is a diagram illustrating a polarization direction of projection light on a polarizing screen in a conventional example.

FIG. 24 is a diagram illustrating characteristics of a color separation system in another conventional example.

[Explanation of symbols]

1r, 1g, 1b Image display element provided in the optical path of R, G, B 2r, 2g, Polarizer provided in the optical path of 2b R, G, B 3r, 3b Phase plate provided in the optical path of R, G, B 101 Light source means Reference Signs List 102 reflector 103 integrator 4 polarization conversion element 6 condenser lens 5 color separation system 51, 52 dichroic mirror 9B, 9G condenser lens 8 relay system 81, 82, 83 relay lens 71, 72, 84, 85 mirror DP color synthesis system (cross Dichroic prism) 12 Projection lens 13 Polarizing screen PJ1, PJ2 Image projector PF1, PF2 Polarizing plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/74 H04N 5/74 K 9/31 9/31 C

Claims (22)

[Claims] 1. A means for supplying light, a color separation system for separating the light from the means into a plurality of color lights, and a plurality of lights for modulating each of the color lights separated by the color separation system based on an image signal. A modulation device, a color combining system that combines the color lights emitted from the light modulation devices, and a projection device that projects the light combined by the color combining system. The color light having a dichroic film and being incident on the dichroic film is linearly polarized light, and the angle between the polarization direction of the color light transmitted through the dichroic film and the polarization direction of the color light reflected by the dichroic film is θ. An image projection apparatus characterized by satisfying 0 ° <θ <90 °. 2. A means for supplying light, a color separation system for separating the light from the means into a plurality of color lights, and a plurality of lights for modulating each of the color lights separated by the color separation system based on an image signal. A projection device having a modulation element, a color synthesis system for synthesizing the color lights emitted from the light modulation elements, and a projection optical system for projecting the light synthesized by the color synthesis system onto a polarizing screen. Has a plurality of dichroic films, each of the color lights incident on the dichroic film is a linearly polarized light, and the angle between the polarization direction of the color light transmitted through the dichroic film and the polarization direction of the color light reflected by the dichroic film. Where 0 ° <θ <90 ° is satisfied, a １ ／ phase plate is arranged in the optical path from the color synthesis system to the polarizing screen, and the color light passing through the dichroic film is Image projection apparatus, wherein the angle between the transmitting polarization direction of the polarizing screen and light direction is substantially equal to the transmission polarization direction of the angle of the polarizing screen to the polarization direction of the color lights reflected by the dichroic film. 3. An image projection apparatus according to claim 2, wherein said half-phase plate is provided at an emission portion of a projection lens of said projection optical system. 4. An image projection apparatus according to claim 2, wherein said half-phase plate is provided between said color synthesizing means and a projection lens of said projection optical system. 5. The image projection apparatus according to claim 2, wherein a slow axis of said half-phase plate rotates around an optical axis of said projection optical system. 6. A means for supplying a plurality of color lights, a plurality of light modulation elements for modulating each of the color lights based on an image signal, a color synthesis system for synthesizing the color lights emitted from each of the light modulation elements, and a color synthesis. And a projection optical system for projecting light synthesized by the system, wherein each color light incident on the dichroic film of the color synthesis system is a linearly polarized light, and a polarization direction of the color light transmitted through the dichroic film. And an angle θ between the polarization directions of the color lights reflected by the dichroic film is 0 ° <θ <90 °. 7. The image projection apparatus according to claim 1, wherein the polarization direction of the color light component reflected by the dichroic film is S-polarized light with respect to the dichroic film. 8. The image projection apparatus according to claim 1, wherein said angle θ satisfies 0 ° <θ <80 °. 9. The image projection apparatus according to claim 1, wherein the angle θ satisfies 0 ° <θ <60 °. 10. The image projection apparatus according to claim 1, wherein said angle θ satisfies 0 ° <θ <45 °. 11. The image projection apparatus according to claim 1, wherein said angle θ is θ = 45 °. 12. An observer wears polarized glasses for selectively inputting light of different polarization states to the left and right eyes, and projects the polarized light on a polarizing screen for preserving the polarization direction by the first and second projection devices. From the parallax image thus obtained, in an image observation device for observing a stereoscopic image, the first and second image projection devices are each configured to supply light and separate the light from the device into a plurality of color lights. A color separation system, a plurality of light modulation elements that modulate the respective color lights based on image signals, a synthesis system having a plurality of dichroic films that synthesize the color lights emitted from the respective light modulation elements, and a synthesis system that is synthesized by the color synthesis system. A projection optical system for projecting the reflected light onto the polarizing screen, and a polarization direction of the color light that is transmitted through the dichroic film and is reflected by the dichroic film, which is disposed in an optical path to the color combining system and the polarizing screen. A polarizing plate whose polarization axis is oriented in a direction that divides the angle between the polarization directions of light into two equal parts, wherein the color lights incident on the dichroic film are linearly polarized lights, respectively, and the color lights transmitted through the dichroic film are all. When the angle between the polarization direction of the component and the polarization direction of the color light component reflected by the dichroic film is θ, 0 ° <θ <90 °
And a phase plate capable of changing the polarization state of light is provided at a light emission position of at least one of the first and second image projection devices, whereby
An image observation apparatus characterized in that the polarization states of light projected by the two projection apparatuses are different. 13. The image observation apparatus according to claim 12, wherein the angle θ satisfies 0 ° <θ <80 °. 14. The image observation apparatus according to claim 12, wherein the angle θ satisfies 0 ° <θ <60 °. 15. The image observation apparatus according to claim 12, wherein the angle θ satisfies 0 ° <θ <45 °. 16. The image observation apparatus according to claim 12, wherein the angle θ is θ = 45 °. 17. The method according to claim 1, wherein:
A system for projecting an image created by a computer using the image projecting device described in the above section. 18. The image projection apparatus according to claim 1, wherein θ = 80 degrees. 19. The image observation apparatus according to claim 12, wherein the angle θ is 80 degrees. 20. The image projection apparatus according to claim 6, wherein a half-wave plate is provided in a light exit portion of the projection optical system. 21. The image projection apparatus according to claim 6, further comprising a half-wave plate between said projection optical system and said color synthesis system. 22. The 1 / about the optical axis of the projection optical system.
22. The image projection device according to claim 20, wherein a slow axis of the two-wave plate is rotatable.