JPH0815639A - Projection type display device using deformed mirror type spacial light modulator element - Google Patents

Abstract

PURPOSE:To project/display a picture by a spacial light modulation element having a wide area without expanding an optical system and to effectively use the light quantity of a light source. CONSTITUTION:This projection type display device is provided with a light source 1, a heat wave cutting filter 2 for removing the heat ray of a light beam from the light source 1, a condenser lens 3 converting the light beam whose heat ray is removed to almost a parallel beam, a deformed mirror type spacial light modulator element 4 for modulating the parallel light beam complied with a picture signal, a projection lens 5 for projecting the reflected beam from the spacial light modulator element 4 and a light shielding plate 8 shielding the reflected beam out of the direction of an optical axis among the beams modulated by the spacial light modulator element 4 and forming the entrance pupil 5a of a projection lens 5. The deformed mirror type spacial light modulator element 4 has some power as a whole and is composed so that a light beam diverged from the light source 1 is converged on the entrance pupil 5a of the projection lens 5 when all mirrors of the element 4 are oriented to the direction in which a light beam is made incident on the projection lens 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device for projecting an image by irradiating a deforming mirror type spatial light modulator with light from a light source.

[0002]

2. Description of the Related Art Conventionally, an electric image signal is enlarged and projected,
A transmissive liquid crystal is used to display on the screen image, and the pattern of the image is drawn by electrically controlling the orientation of the liquid crystal to change the transmittance, irradiating the liquid crystal with light and enlarging and projecting with a projection lens. are doing. FIG. 4 is a main part configuration diagram showing one of conventional examples of this type of projection display device.

This projection type display device, as shown in FIG.
A light source 41 including a halogen lamp or a metal halide lamp, a heat ray cut filter 43 that absorbs or reflects heat rays of a light flux incident through a reflection mirror 42 that reflects a part of the light flux emitted from the light source 41, and the heat rays are A condenser lens 44 that converts the removed light flux into a parallel light flux, a polarizing plate 45 that converts the parallel light flux into a linearly polarized light, a liquid crystal light valve 47 that modulates the linearly polarized light according to an image signal, and the modulated light. A polarizing plate 48 that transmits only the component of the linearly polarized light in the transmission axis direction and a projection lens 49 that magnifies and projects the transmitted linearly polarized light on a screen (not shown) are provided.

However, in the projection type display device shown in FIG. 4, only the linearly polarized light component of the light flux emitted from the light source 41 that passes through the polarizing plate 45 is used as the illumination light of the liquid crystal light valve 47, and the transmitted straight line. Since the linearly polarized light component orthogonal to the polarized light component is lost, the light utilization efficiency is 5
There was a drawback that it was 0% or less.

Therefore, a modified mirror type spatial light modulator is used instead of the liquid crystal to reduce the loss of light.
It is possible that the amount of light on the screen is increased.

This modified mirror type spatial light modulator is disclosed for each pixel as shown in Japanese Patent Application Laid-Open No. 61-129627, Japanese Patent Publication No. 3-78622, and Japanese Patent Application Laid-Open No. 58-10714. It is an element that switches the direction of light reflected by the mirror surface by tilting the mirror surface made of a metal thin film by the Coulomb force of electric charges.

FIG. 5 is a view showing the structure of a cantilever type modified mirror type spatial light modulator.

In FIG. 5, reference numeral 51 is a mirror oscillating portion which is made of a material such as Al or Ag and serves to reflect incident light, reference numeral 52 is a hinge, reference numeral 53 is an air gap, and reference numeral 54 is a field plate. Reference numeral 55 is a floating source, reference numeral 56 is a drain, and reference numeral 57 is a metal gate. A voltage is applied to the field plate 54 from the floating source 55 according to the ON / OFF information of the transistor. With this voltage, the mirror swing unit 51
The hinge 52 bends and swings.

FIG. 6 is a block diagram showing a conventional projection type display device using a modified mirror type spatial light modulator.

As shown in FIG. 6, the conventional projection type display device is incident via a light source 61 composed of a halogen lamp or a metal halide lamp, and a reflection mirror 62 for reflecting a part of a light beam emitted from the light source 61. A heat ray cut filter 63 that absorbs or reflects heat rays of a light beam, a condenser lens 64 that converts the light rays from which the heat rays have been removed into substantially parallel light rays, and a deforming mirror type spatial light modulation that modulates the parallel light rays according to an image signal. The element 67, a field lens 66 that transmits and collects a component of the modulated light in the optical axis direction to form an image of a light source on an entrance pupil 69a of a projection lens 69 described later, and light transmitted through the field lens 66. Of the light modulated by the deforming mirror type spatial light modulator 67 and reflected outside the optical axis direction. Light was blocked, and the projection lens 6
The light-shielding plate 68 which forms the nine entrance pupils 69a.

[0011]

However, in the above-mentioned conventional projection type display device, the projection lens becomes large as the area of the deforming mirror type spatial light modulator increases. Further, even if the light flux is focused on the entrance pupil of the projection lens using the field lens, the field lens itself becomes large. For these reasons, there is a problem in that as the size of the deforming mirror type spatial light modulator increases, the size of the optical system also increases.

Further, when a field lens is used, there is a problem in that the field lens reduces the light transmission efficiency.

In view of the above-mentioned problems of the prior art, the present invention projects and displays an image by a spatial light modulator having a large area without increasing the size of the optical system, and moreover the light quantity of the light source is effective. It is an object of the present invention to provide a projection type display device using a deformable mirror type spatial light modulator that can be used for

[0014]

In order to achieve the above object, the present invention provides a modified mirror type spatial light modulation device which allows a luminous flux diverging from a light source to pass through a condenser lens and enter a modified mirror type spatial light modulation device. A modified mirror type spatial light modulator is used which forms an image by projecting an image of an object by the modified mirror type spatial light modulator on a screen by causing a part of light reflected by the element to enter an entrance pupil of a projection lens. In the projection display device, the image of the object does not electrically switch the angle of the mirror surface of each pixel of the deformable mirror type spatial light modulator to allow reflected light from the mirror surface to enter the projection lens. The deformed mirror type spatial light modulator has a certain power as a whole when all the mirrors are oriented in the direction of incidence on the projection lens. Characterized in that it is configured so as to focus the divergent light flux into the entrance pupil of the projection lens.

In the projection type display device using the modified mirror type spatial light modulator, a diffuser plate is installed in the optical path between the modified mirror type spatial light modulator and the light source, or the modified mirror type. The mirror surface for each pixel of the spatial light modulator may be a diffusion surface that diffuses light.

[0016]

In the present invention configured as described above, the modified mirror type spatial light modulator has a certain power as a whole when all mirrors of this element are directed in the direction in which the light beam is incident on the projection lens. The light beam diverging from the light source is focused on the entrance pupil of the projection lens. The light flux that illuminates the image on the modified mirror type spatial light modulator by this so-called Koehler illumination is efficiently projected onto the screen through the projection lens.

Due to this, even if the area of the element becomes large, it is not necessary to enlarge the projection lens or to enlarge the field lens to focus the light on the entrance pupil of the projection lens. Therefore, the optical system does not become large, and since the field lens is not used, the amount of light from the light source can be effectively used.

[0018]

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

(First Embodiment) FIG. 1 is a block diagram showing the first embodiment of the projection type display device of the present invention.

As shown in FIG. 1, the projection display apparatus of this embodiment comprises a light source 1 composed of a halogen lamp, a metal halide lamp, etc., and a heat ray cut filter 2 for absorbing or reflecting the heat rays of the luminous flux emitted from the light source 1. A condenser lens 3 for converting the light flux from which the heat rays have been removed into a substantially parallel light flux, a modified mirror type spatial light modulation element 4 for modulating the parallel light flux according to an image signal, and a modified mirror type spatial light modulation element 4 A projection lens 5 for projecting the reflected light from the screen 7 onto a screen 7, and a light which is reflected outside the optical axis direction out of the light modulated by the deforming mirror type spatial light modulation element 4 is shielded and an entrance pupil of the projection lens 5 And a light shielding plate 8 forming 5a.

The deforming mirror type spatial light modulator 4 projects a light beam having a certain power as a whole and diverging from the light source 1 when all the mirrors of this device 4 are oriented in the direction of making the light beam enter the projection lens 5. It is configured to focus the light on the entrance pupil 5a of the lens 5. In other words, the modified mirror type spatial light modulation element is configured such that when all the mirrors of this element are in positions where they reflect light to the projection lens, the mirrors are gradually adjusted so that the normal line of each mirror faces the entrance pupil of the projection lens. The tilted reflected light beam is narrowed down. The light flux condensed on the projection lens 5 by the deforming mirror type spatial light modulation element 4 has substantially the same shape as the entrance pupil 5 a of the projection lens 5.

In the above-mentioned structure, the light beam emitted from the light source 1 is incident on the heat ray cut filter 2, and the heat ray is absorbed or reflected by the heat ray cut filter 2.
The light flux from which the heat rays have been removed is incident on the condenser lens 3, is converted into a substantially parallel light flux by the condenser lens 3, and is incident on the deforming mirror type spatial light modulator 4 that modulates in accordance with the image signal.

The modified mirror type spatial light modulator 4 is controlled by an electric signal, and an image is formed by switching the direction of the reflected light with a mirror for each pixel.

Further, the modified mirror type spatial light modulator 4 is
When all the mirrors of this element 4 are oriented in the direction in which the light beam is incident on the projection lens 5, the light beam having a certain power as a whole and diverging from the light source 1 is incident pupil 5a of the projection lens 5.
Focus on. The light flux that illuminates the image on the modified mirror type spatial light modulator 4 by this so-called Koehler illumination is efficiently projected onto the screen 4 through the projection lens 5.

As described above, in the present embodiment, when all the mirrors are oriented in the direction in which the light flux is incident on the projection lens, the light flux having a certain power as a whole and diverging from the light source is focused on the entrance pupil of the projection lens. By including the modified mirror type spatial light modulator configured to emit light, the image of the light source can be displayed without increasing the size of the projection lens or using the field lens even if the area of the light modulator increases. It can be made on the entrance pupil of the projection lens. Therefore, the optical system does not become large even if the area of the light modulation element becomes large, and since the field lens is not used, the amount of light from the light source does not decrease.

(Second Embodiment) FIG. 2 is a block diagram showing a second embodiment of the projection type display device of the present invention.

As shown in FIG. 2, the projection type display device of this embodiment has a light source 21 composed of a halogen lamp, a metal halide lamp, etc., and a heat ray cut filter 22 for absorbing or reflecting the heat ray of the luminous flux emitted from the light source 21. A condenser lens 23 for converting the light flux from which the heat rays have been removed into a substantially parallel light flux, a modified mirror type spatial light modulation element 24 for modulating the parallel light flux according to an image signal, and a modified mirror type spatial light modulation element 24. The reflected light from the screen 27
A projection lens 25 for projecting light onto the projection lens 25, and a light shield plate 28 for blocking the light reflected outside the optical axis direction out of the light modulated by the deforming mirror type spatial light modulator 24 and forming an entrance pupil 25a of the projection lens 25. Have and. Further, in the parallel light flux from the condenser lens 23 to the deforming mirror type spatial light modulator 24, a diffusing plate 26 such as an opal plate is provided so that the light flux entering the entrance pupil 25a of the projection lens 25 has a uniform light quantity distribution. Is installed.

In the modified mirror type spatial light modulator 24, when all the mirrors are oriented in the direction in which the light beam is incident on the projection lens 25, the light beam emitted from the light source 21 and having a certain power as a whole is incident on the projection lens 25. The light is focused on the pupil 25a. In other words, the modified mirror type spatial light modulation element is configured such that when all the mirrors of this element are in positions where they reflect light to the projection lens, the mirrors are gradually adjusted so that the normal line of each mirror faces the entrance pupil of the projection lens. The tilted reflected light beam is narrowed down. The light beam condensed on the projection lens 25 by the deforming mirror type spatial light modulation element 24 has substantially the same shape as the entrance pupil 25 a of the projection lens 25.

In the above structure, the light beam emitted from the light source 21 enters the heat ray cut filter 22, and the heat ray is absorbed or reflected by the heat ray cut filter 22. The light flux from which the heat rays have been removed enters the condenser lens 23 and is converted into a substantially parallel light flux by the condenser lens 23.

The parallel light flux from the condenser lens 23 is diffused by the diffuser plate 26 and is incident on the deforming mirror type spatial light modulator 24.

The modified mirror type spatial light modulator 24
Is controlled by an electric signal, and an image is formed by switching the direction of reflected light with a mirror for each pixel.

In addition, the modified mirror type spatial light modulator 24
Means that when all the mirrors of the element 24 are oriented in the direction in which the light beam is incident on the projection lens 25, the light beam having a certain power as a whole and diverging from the light source 21 through the diffusion plate 26 is incident pupil of the projection lens 25. Focus on 25a. At this time, the entrance pupil 25a of the projection lens 25 is illuminated with a uniform light amount distribution. The light flux that illuminates the image on the modified mirror type spatial light modulator 24 by this so-called Koehler illumination is efficiently projected onto the screen 24 through the projection lens 25.

As described above, in this embodiment, in addition to the structure described in the first embodiment, the diffuser plate is installed in the optical path between the deforming mirror type spatial light modulator and the light source, so that the uniform structure can be obtained. Images can be displayed with various light intensity distributions. In other words, it is difficult to illuminate the entrance pupil of the projection lens with a uniform light amount distribution because the illumination optical system decreases the light amount as the distance from the optical axis increases.However, in the present embodiment, the diffuser plate is used to obtain a uniform light amount distribution. Was achieved.

(Third Embodiment) FIG. 3 is a block diagram showing a third embodiment of the projection type display device of the present invention.

As shown in FIG. 3, the projection display apparatus of this embodiment has a light source 31 composed of a halogen lamp, a metal halide lamp, etc., and a heat ray cut filter 32 for absorbing or reflecting the heat ray of the luminous flux emitted from the light source 31. A condenser lens 33 that converts the light flux from which the heat rays have been removed into a substantially parallel light flux, a modified mirror type spatial light modulation element 34 that modulates the parallel light flux in accordance with an image signal, and a modified mirror type spatial light modulation element 34. The reflected light from the screen 37
A projection lens 35 for projecting light onto the optical axis, and a light shield plate 38 for blocking the light reflected out of the optical axis direction out of the light modulated by the deforming mirror type spatial light modulator 34 and forming an entrance pupil 35a of the projection lens 35. Have and.

In the modified mirror type spatial light modulator 34, when all the mirrors are oriented in the direction in which the light flux enters the projection lens 35, the light flux emitted from the light source 31 has a certain power as a whole and enters the projection lens 35. It is configured to focus the light on the pupil 35a. In other words, the modified mirror type spatial light modulation element is configured such that when all the mirrors of this element are in positions where they reflect light to the projection lens, the mirrors are gradually adjusted so that the normal line of each mirror faces the entrance pupil of the projection lens. The tilted reflected light beam is narrowed down.

Further, the mirror surface of each pixel of the deformable mirror type spatial light modulator 34 is processed so as to diffuse light so that the light beam incident on the entrance pupil 35a of the projection lens 35 has a uniform light amount distribution. It has been subjected. Further, the light flux condensed on the projection lens 35 by the deforming mirror type spatial light modulation element 34 has substantially the same shape as the entrance pupil 35 a of the projection lens 35.

With the above-described structure, the light beam emitted from the light source 31 is incident on the heat ray cut filter 32, and the heat ray is absorbed or reflected by the heat ray cut filter 32. The light flux from which the heat rays have been removed enters the condenser lens 33 and is converted into a substantially parallel light flux by the condenser lens 33.

The parallel light flux from the condenser lens 33 enters the deforming mirror type spatial light modulator 34.

The modified mirror type spatial light modulator 34
Is controlled by an electric signal, and an image is formed by switching the direction of reflected light with a mirror for each pixel.

In addition, the modified mirror type spatial light modulator 34.
When all the mirrors of the element 34 are oriented in the direction in which the light flux is incident on the projection lens 35, the projection lens 35 transmits the light flux having a certain power as a whole and diverging from the light source 31.
The light is focused on the entrance pupil 35a. The light flux that illuminates the image on the modified mirror spatial light modulation element 34 by this so-called Koehler illumination is projected as a light flux having a uniform light quantity distribution by the diffusion processing of each mirror surface of the modified mirror spatial light modulation element 34. The light is focused on the entrance pupil 35 a of the lens 35 and is efficiently projected on the screen 34 through the projection lens 35.

As described above, in this embodiment, in addition to the structure described in the first embodiment, processing is performed to diffuse light on the mirror surface of each pixel of the modified mirror type spatial light modulator. The image can be displayed with a uniform light amount distribution. In other words, it is difficult to illuminate the entrance pupil of the projection lens with a uniform light amount distribution because the illumination optical system has a light amount that decreases as the distance from the optical axis increases. It was possible to achieve a uniform light intensity distribution display by diffusing the mirror surface of.

[0043]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, when all the mirrors of the element are oriented in the direction of incidence on the projection lens, the luminous flux diverging from the light source having a certain power is focused on the entrance pupil. By constructing a modified mirror type spatial light modulator in, the image of the spatial light modulator with a large area can be projected and displayed without increasing the size of the optical system, and the light quantity of the light source can be used effectively. You can

According to a second aspect of the present invention, in addition to the effect of the first aspect, a diffuser plate is installed in the optical path between the deforming mirror type spatial light modulator and the light source, so that the uniform light can be obtained. Images can be displayed with various light intensity distributions.

According to a third aspect of the present invention, in addition to the effect of the first aspect, a process is performed to diffuse light on the mirror surface of each pixel of the modified mirror type spatial light modulator. The image can be displayed with a uniform light amount distribution.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a projection type display device of the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the projection type display device of the present invention.

FIG. 3 is a configuration diagram showing a third embodiment of the projection type display device of the present invention.

FIG. 4 is a main part configuration diagram showing one of conventional examples of a projection type display device using liquid crystal.

FIG. 5 is a diagram showing a structure of a cantilever type modified mirror type spatial light modulator.

FIG. 6 is a configuration diagram showing a conventional projection type display device using a modified mirror type spatial light modulator.

[Explanation of symbols]

 1, 21, 31 Light source 2, 22, 32 Heat ray cut filter 3, 23, 33 Condenser lens 4, 24, 34 Deformation mirror type spatial light modulator 5, 25, 35 Projection lens 5a, 25a, 35a Entrance pupil 26 Diffuser plate 7,27,37 Screen 8,28,38 Light shield

Claims (3)

[Claims] 1. A light flux diverging from a light source is transmitted through a condenser lens and is incident on a deforming mirror type spatial light modulating element, and a part of light reflected by the deforming mirror type spatial light modulating element is incident on an entrance pupil of a projection lens. In the projection display device using the deformable mirror type spatial light modulator, the image of the object is projected onto the screen by the deformable mirror type spatial light modulator to form an image, wherein the image of the object is the deformable mirror. The modified mirror type spatial light modulator is formed by electrically switching the angle of the mirror surface of each pixel of the type spatial light modulator to prevent the reflected light from the mirror surface from entering the projection lens. Is that when all the mirrors are oriented in the direction of incidence to the projection lens, the light flux that has a certain power as a whole and diverges from the light source is focused on the entrance pupil of the projection lens. Characterized in that it is configured to,
A projection type display device using a deforming mirror type spatial light modulator. 2. A diffuser plate is installed in an optical path between the modified mirror type spatial light modulator and the light source.
A projection type display device using the modified mirror type spatial light modulator according to claim 1. 3. The modified mirror type spatial light modulator according to claim 1, wherein the mirror surface of each pixel of the modified mirror type spatial light modulator is a diffusion surface for diffusing light. Projection type display device.