JPH08327960A - Picture projection device - Google Patents

Abstract

PURPOSE: To provide a multi-plate type projector constituted so that the quality of a projected picture is prevented from being deteriorated. CONSTITUTION: By display devices 20, 22 and 24, a blue, a green and a red light beams including the blue, the green and the red components of an original video are emitted. Then, reference light beams made incident on the display devices 20, 22 and 26 from a reference light beam source 112 are successively detected by the optical detectors disposed at prescribed positions on the display devices and inputted to correction devices 30, 32 and 34 as electric signal S42ij . By the correction devices 30, 32 and 34, the deviation of the display devices 20, 22 and 24 from a correct position is detected based on the signal S42ij . Then, the display devices 20, 22 and 24 are moved to be returned to the correct position so as to compensate the deviation. By an L-shaped prism 140, the light beams emitted by the display devices 20, 22 and 24 are overlapped, composited and projected on a screen and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image projection apparatus for superimposing images generated for each of the three primary colors of light using a liquid crystal display device or the like to synthesize a color image and projecting and displaying the combined color image.

[0002]

2. Description of the Related Art Using a plurality of display devices, the images generated by the respective display devices are superposed to generate one image,
A multi-plate image projection device (projector) that projects on a screen or the like is used. A display device of a multi-plate projector, for example, decomposes an original color image into components of three primary colors of light, adds the components of these images to light of the three primary colors of light, synthesizes them, and projects in an enlarged scale. Is configured.

[0003]

The position of the display device of the multi-plate type projector may be changed over time after manufacturing, or
It will be displaced due to deformation of the device due to heat generated during use. However, such a positional shift of the display device does not have a great influence on the image quality when displaying an image having a resolution of a normal television broadcast, and is therefore usually ignored. However, when a high-resolution image such as a high-definition television (HDTV or high-definition) broadcast that has been put into practical use in recent years is projected, the displacement of the position of the display device has a great influence on the image. That is, the position of the display device in the steady state before the start of use is
Even if the position is exactly adjusted to the desired position, the relative position of the display device is displaced due to heat generated from the light source or the like during use, and this displacement is relatively larger than the pixel of the image of the HDTV. As a result, the image quality is deteriorated due to coloring to white or color unevenness.

The present invention has been made in view of the above-mentioned problems of the prior art, and when a plurality of display devices of a multi-plate type projector have positional deviations, the positional deviations are detected and automatic It is an object of the present invention to provide an image projection device that can be corrected dynamically. Another object of the present invention is to provide an image projection device capable of preventing deterioration of the image quality of a projected image by automatically correcting the position of the display device.

[0005]

In order to achieve the above-mentioned object, an image projection apparatus according to the present invention generates parallel projection light, and red light, green light and blue light are generated from the projection light. A first optical system for extracting light and the red light,
The three liquid crystal display means for transmitting the green light and the blue light to generate a reference image, and the beam-like reference light beam indicating the reference of the position of each of the three liquid crystal display means are passed through the first optical system. A reference light beam irradiating means for irradiating a predetermined position of each of the three liquid crystal display means through
Positional deviation detecting means for receiving the reference light beam irradiated to the predetermined position of each of the three liquid crystal display means and detecting a positional deviation between the reference position and the actual position of the three liquid crystal display means, respectively. A second optical system for synthesizing and projecting the position correcting means for correcting the position of each of the three liquid crystal display means and the reference image generated by each of the three liquid crystal display means so as to cancel each of the positional deviations. Have and.

The position correcting means expands and contracts according to the temperature and fixes the liquid crystal display means at a predetermined position, and the temperature of each of the fixing members based on each of the detected positional deviations. And the length of these liquid crystal display means is expanded or contracted to correct the position of each of the three liquid crystal display means.

The position shift detecting means are provided at predetermined positions of the three liquid crystal display means, respectively, and three light receiving means for converting the received reference light rays into electric signals and the three liquid crystal display means are provided. Based on each of the electrical signals converted by the three light receiving means provided at a predetermined position of the means, each of the positional deviations between the reference position and the actual position of the three liquid crystal display means is detected. And a detection means.

[0008]

The first optical system extracts the light of the three primary colors (red light, green light and blue light) from the light for projection generated by the predetermined light source. Each of the three liquid crystal display means uses the three components corresponding to the three primary colors of light included in the original color image to correspond to the red light, the green light and the blue light, respectively, to correspond to the three components of the original color image. Attach the image you want. The reference light beam irradiating means uses a beam-like light beam such as a laser beam for pointing a position where a predetermined point of the liquid crystal display means should be located, when each of the three liquid crystal display means is in a correct position, as a reference light beam. Irradiate each.

The position shift detecting means has a light receiving element which is divided into a matrix and is arranged at a position where the reference light beams of the three liquid crystal display means are irradiated, and when the display device is in the correct position. The positional deviation between the position of the light receiving element that is irradiated with the reference light beam and the position of the light receiving element that is actually irradiated with the reference light beam is detected as the positional deviation of the position of the display device.

The position correction means is, for example, the liquid crystal display means detected by the position deviation detection means so that the images given to the light of the three primary colors of the light by the liquid crystal display means are overlapped without a position deviation to form the original color image. The position of each liquid crystal display means is moved in a direction to cancel the deviation from the correct position, and each liquid crystal display means is returned to the correct position. The second optical system superimposes and combines the three primary colors of light with an image on each of the liquid crystal display means, and projects them onto a screen or the like.

[0011]

Embodiments of the image projection apparatus (projector) according to the present invention will be described below. FIG. 1 is a diagram showing a configuration of a multi-plate type projector 1 according to the present invention. Figure 2
2 is a diagram showing a configuration of the display devices 20, 22, and 24 shown in FIG. 1, and FIG.
It is sectional drawing cut | disconnected by the -X 'plane, (B) is the top view which looked at the display devices 20, 22, and 24 from Z side. Figure 3
FIG. 3 is a diagram showing a configuration of the correction devices 30, 32, 34 shown in FIG. 1. FIG. 4 is a diagram showing the configuration of the photodetector 40 of the correction devices 30, 32, 34 shown in FIGS. 2 and 3.

As shown in FIG. 1, the projector 1 is
Parabolic reflector 100, projection light source 110, reference light source 112, UV / IR filter 114, pre-polarizer (PP
L) 116, condenser lens 118, dichroic mirrors 120, 122, 124, 126, blue filter 130 with polarizing element, green filter 1 with polarizing element
32, a red filter 134 with a polarizing element, an L-type prism 140, display devices 20, 22, 24, a correction device 30,
32, 34 and a projection lens 150.

The L-shaped prism 140 is the first prism 1
42 and the second prism 144. The projector 1 includes the display device 2 having the above-described components.
Each of 0, 22, and 24 superimposes the light of the three primary colors of the light with the three components corresponding to the three primary colors of the original image without error, and synthesizes and displays it on a predetermined screen (not shown).

The reference light source 112 is, for example, a laser diode and generates a beam-like reference light that indicates the reference of the position of the display device 20, 22, 24, and the display device 2.
The photodetector 40 arranged at a predetermined position of each of 0, 22, and 24 is irradiated. The parabolic reflector 100 reflects the projection light generated by the projection light source 110 and removes unnecessary wavelength light such as ultraviolet rays from the UV / IR filter 114, and partially deflects the light. The light enters the condenser lens 118 through the PPL 116 that generates light according to natural light. The condenser lens 118 is the parabolic reflector 1.
The light reflected at 00 and incident through the UV / IR and PPL 116 is collimated.

Dichroic mirrors 120, 122, 1
24 and 126 are arranged in the respective angles and positional relationships as shown in FIG. 1, and as shown by the solid line in FIG. 1, transmit or reflect the component of the predetermined wavelength of the incident projection light, and As indicated by the dotted line, a part of the reference light beam is transmitted or reflected and guided to the photodetector 40 of each of the display devices 20, 22, 24. The blue filter 130, the green filter 132, and the red filter 134 respectively take out components of the three primary colors (blue B, green G, and red R) of light from the incident projection light and display blue light, green light, and red light, respectively. Emit to devices 20, 22, 24.

The display devices 20, 22, and 24 are, for example, liquid crystal display devices capable of displaying halftones of images, and a blue component and a green component obtained by decomposing an original color image into three primary color components of light. A blue component, a red component, a blue component, a red component, a blue component, a red component, a blue component, a green component, and a red component, respectively. The image corresponding to the blue component, the green component, and the red component of the image is attached and emitted. The display device 2
The configuration and operation of 0, 22, and 24 will be described in further detail with reference to FIGS. 2 and 3.

The correction devices 30, 32, and 34 are electric signals S4 from the light receiving elements 42 _ij (FIG. 3) of the photodetector 40 which are arranged at predetermined positions of the display devices 20, 22, and 24, respectively.
The positions of the display devices 20, 22, and 24 are corrected based on 2 _ij . The configuration and operation of the correction devices 30, 32, 34 will be described in further detail with reference to FIG.

The prism 142 of the L-shaped prism 140 is
The blue light incident from the display device 20 is transmitted, the green light incident from the display device 22 is reflected, and these lights are superposed. The prism 144 of the L-type prism 140 superimposes the red light and the light incident from the prism 142.

As described herein, the L-shaped prism 140
Prisms 142, 144 of the display device 20, 22, 2
4, the blue light, the green light and the red light to which the images corresponding to the blue color component, the green color component and the red color component of the original color image are respectively added and combined to reproduce the original color image to reproduce the projection lens 150. Emit to. Projection lens 1
Reference numeral 50 projects an image reproduced by each component of the projector 1 described above on a screen.

The configurations and operations of the display devices 20, 22, and 24 will be further described below with reference to FIGS. 2 and 3. 2 and 3, the signal lines connecting the photodetector 40 and the correction devices 30, 32, 34 are omitted in FIG. 2 and FIG. 3. As shown in FIG. 2, each of the display devices 20, 22, and 24 has a holding member 2
00, display 220 and fixing members 208 _{1 to} 208 ₈
The display unit 220 includes a frame member 202,
Liquid crystal display unit 204, photodetector 40 and Peltier device 2
10, 210 ', 212, 212', 214, 21
4 ', 216, 216'.

The frame member 202 of the display section 220 is a fixing member 208 _{1 to} 208 ₈ such as an aluminum material which expands and contracts according to temperature.
It is fixed to the holding member 200 by. Peltier elements 210, 210 ′, 212 arranged on the frame member 202,
212 ′, 214, 214 ′, 216, 216 ′ are configured such that when a current is applied, the temperature of any one of the end portions rises and the temperature of the other end portion falls, and the fixing members 208 are respectively provided. ₁ , 208 ₂ , fixing members 208 ₃ , 208
₄ , fixing members 208 ₅ , 208 ₆ , fixing members 208 ₇ ,
Adjust the temperature of 208 ₈ .

For example, when the correction devices 30, 32, and 34 apply current to the Peltier elements 210 and 210 'so that the temperature on the side of the fixing member 208 ₁ rises and the temperature on the side of the fixing member 208 ₂ decreases, the Peltier elements 210, 210' are fixed. The member 208 ₁ expands, on the contrary, the fixing member 208 ₂ contracts, and the display unit 220 moves toward the left side in FIG. 2. Similarly, the correction devices 30, 32, and 34 are connected to other Peltier elements 212 ′, 212, 214, 214 ′, 21.
It is possible to move the display unit 220 in an arbitrary direction and correct its position by controlling the currents flowing in the channels 6, 216 '.

The liquid crystal display unit 204 is held by the frame member 202 and displays the blue component, green component and red component of the original color image. The photodetector 40 is composed of light receiving elements 42 _ij (i and j are integers) such as phototransistors arranged in a matrix as shown in FIG. 3, and each of the light receiving elements 42 _ij receives a reference light beam. Then, the electric signal S having a voltage value proportional to the intensity of the received reference light beam
It is converted into 42 _ij and output to the correction devices 30, 32 and 34.

Hereinafter, referring to FIG. 4, the correction devices 30, 3
The configuration and operation of Nos. 2 and 34 will be described. 1 and 4
As shown in FIG. 3, the correction devices 30, 32, 34 are provided corresponding to the display devices 20, 22, 24, respectively.
It is composed of an error detection circuit 36 and a control circuit 38.

The error detection circuit 36 is provided in the display devices 20, 2
Based on the electric signals S42 _ij input from the light receiving elements 42 _{ij of the} 2, 24 photodetectors 40, respectively, the display device 2
It is detected how much the positions of 0, 22, and 24 deviate from the correct position (design value) in the vertical and horizontal directions. Hereinafter, a specific description will be given based on the example shown in FIG. When manufacturing the projector 1, the display devices 20, 22, and 24 are aligned in correct positions, and further, the light receiving element 42 ₀₀ shown in FIG.
When the orientation and position of the reference light source 112 (FIG. 1) are adjusted so that the center of the reference light and the center point of the reference light coincide with each other, when the display devices 20, 22, and 24 are in the correct positions, the light receiving element 42 ₀₀ is the most. The light receiving element 42 strongly receives the reference light beam.
₁₀ , 42 _{0, -1} , 42 ₁₀ , 42 _-1 , ₀ receive the reference ray equally weakly.

However, when the positions of the display devices 20, 22, 24 deviate from the correct positions due to the aging of the projector 1 or the uneven heat distribution generated during use, etc., the light receiving elements 42 _ij and the light receiving elements 42 _ij for receiving the reference rays. The intensity changes. For example, as illustrated in FIG. 3, the light receiving element 42
_-2,1 , 42 _-1,1 , 42 _-2,0 , 42 _-1,0 receive the reference rays almost uniformly, the display devices 20, 22, 24
3 is shifted by 0.5 light receiving elements 42 _{ij in} the downward direction of FIG. 3 and by 1.5 light receiving elements 42 _{ij in} the right direction.

As described above, the error detection circuit 36 includes the light receiving element 42 _ij for receiving the reference light beam and the light receiving element 42 _ij.
From the voltage of the electric signal S42 _ij output from the display device 20, 22, 24 from the correct position (X,
Y) can be detected. The area of the reference light beam and the distance between the light receiving elements 42 _ij are not limited to the required display devices 20, 2
The accuracy of the position correction for 2, 24 can be obtained by, for example, an experiment or calculation.

The control circuit 38 controls the Peltier elements 210, 210 ', 212, 212', 214, 21 so as to cancel the deviation amount (X, Y) detected by the error detection circuit 36.
The currents flowing through 4 ', 216, 216' are controlled to move the display devices 20, 22, 24 back to the correct positions.

The overall operation of the projector 1 will be described below. The projection light generated by the projection light source 110 is reflected by the parabolic reflection mirror 100 and enters the dichroic mirror 120 via the UV / IR filter 114, the PPL 116 and the condenser lens 118.

The blue component (blue light) of the projection light is reflected by the dichroic mirrors 120 and 122, filtered by the blue filter 130, and enters the display device 20. The display device 20 receives the incident blue light,
An image corresponding to the blue component of the above-mentioned original image is attached and emitted to the prism 142.

Of the projection light that has passed through the dichroic mirror 120, the green component (green light) is reflected by the dichroic mirror 124, filtered by the green filter 132, and incident on the display device 22. The display device 22 attaches an image corresponding to the green component of the above-described original image to the incident green light, and outputs the green light to the prism 142.

The projection light (red light) that has passed through the dichroic mirrors 120 and 124 is filtered by the red filter 134 and enters the display device 24. The display device 24 attaches an image corresponding to the red component of the above-described original image to the incident red light, and outputs the red light to the prism 144.

The prisms 142 and 144 are used for the display device 2.
The blue light, green light, and red light to which the images corresponding to the blue component, the green component, and the red component of the original image are respectively added by 0, 22, and 24 are superimposed, and the projection lens 15
Emitting to the screen via 0.

On the other hand, the display devices 20, 22, 24 are respectively
The reference rays incident on the display device 20, 22, 24
The electric signals S are sequentially detected by the respective photodetectors 40.
42 _ijThe error of each of the correction devices 30, 32 and 34 is
Input to the detection circuit 36. Correction device 30, 32, 3
4 each of the error detection circuits 36 is connected to the display device 20, 2
Deviation amount (X, Y) indicating the deviation of 2, 24 is detected and corrected.
For the control circuit 38 of each of the devices 30, 32, 34
Output. Control times of the correction devices 30, 32, 34 respectively
The paths 38 are respectively input from the error detection circuit 36.
Based on the deviation amount (X, Y), the deviation amount (X, Y) is set.
Peltier elements 210, 210 ', 212, 2 to be erased
12 ', 214, 214', 216, 216 '
The flow is controlled and the position of the display device 20, 22, 24 is correct.
Return to position.

For example, the distance between the display portion 220 of the display device 20, 22, 24 and the holding member 200 is 2.9 mm,
When an aluminum material having a length of 20.9 mm is used as the fixing members 208 _{1 to} 208 ₈ , the Peltier elements 210, 210 ′,
212, 212 ', 214, 214', 216, 21
6 ′ 0.5 μ each time a temperature difference of ΔT = 1 ° C. is given to the fixing members 208 _k and 208 _{k + 1} (k is an odd number) side.
It is possible to obtain changes in the positions of the display devices 20, 22, 24 of m. As described above, since the positions of the display devices 20, 22, and 24 can be finely corrected, it is possible to almost completely prevent color unevenness of an image projected by the projector 1 and burn-in to white. Moreover, as compared with the case where an actuator such as a motor is used, this correction can be performed silently and accurately.

As the light receiving element 42 _ij of the photodetector 40, for example, a CCD element can be used instead of the phototransistor. Further, the photodetector 40 can be integrally formed on the polysilicon or TFT of the liquid crystal display section 204. If the reference light source 112 is two and the photodetector 40 receives the two reference lights and the error detection circuit 36 is capable of detecting the positional deviation of these two reference lights, the display devices 20, 22, The inclination θ of 24 can also be detected. Further, the control circuit 38 is arranged so that the Peltier elements 210, 210 ′, 212, 212 ′, 214, 2 at the target position with respect to the center of the liquid crystal display unit 204.
It is more preferable to control the 14 ', 216, and 216' in association with each other so as to cancel the inclination θ detected by the error detection circuit 36.

In addition to the aluminum material as the fixing members 208 _{1 to} 208 ₈ , for example, metals such as SUS and copper, and
Engineering plastic or the like may be used. In addition, the Peltier elements 210, 210 ', 212, 21
Instead of 2 ', 214, 214', 216, 216 ', a semiconductor element or a heating element using a nichrome wire may be used.

Further, in the above-described embodiment, the projector 1 is configured so as to correct the absolute position with respect to the reference light beam from the reference light source 112, but the display is relatively performed within a predetermined range. The same effect can be achieved by performing the position correction of the devices 20, 22, 24. In addition to the above-described embodiments, the image projection apparatus according to the present invention can be modified as in the modification shown here, or, for example, the error detection circuit 36 and the control circuit 3.
Various configurations can be taken, such as 8 being common to all the display devices 20, 22, 24.

[0039]

As described above, according to the image projection apparatus of the present invention, when a plurality of display devices of a multi-plate type projector are misaligned, the misalignment is automatically detected. Can be corrected to. Further, according to the image projection apparatus of the present invention, it is possible to prevent the deterioration of the image quality of the projected image by automatically correcting the position of the display apparatus.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a multi-plate type projector according to the present invention.

2A and 2B are diagrams showing a configuration of the display device shown in FIG. 1, in which FIG. 2A is a cross-sectional view of the display device taken along a plane XX ′, and FIG. It is a top view.

FIG. 3 is a diagram showing a configuration of a correction device shown in FIG.

FIG. 4 is a diagram showing a configuration of a photodetector of the correction apparatus shown in FIGS. 2 and 3.

[Explanation of symbols]

1 ... Projector, 100 ... Parabolic reflector, 112 ...
Reference light source, 114 ... UV / IR filter, 116 ...
PPL, 118 ... Condenser lens, 130 ... Blue filter, 132 ... Green filter, 134 ... Red filter,
120, 122, 124, 126 ... Dichroic mirror, 140 ... L-type prism, 142, 144 ... Prism, 150 ... Projection lens, 20, 22, 24 ... Display device, 200 ... Holding member, 220 ... Display unit, 202 ... Frame member, 204 ... liquid crystal display unit, 208 _{1 to 208 8} ... fixing member, 210, 210 ', 212, 212', 214,2
14 ', 216, 216' ... Peltier device, 30, 3
2, 34 ... Correction device, 36 ... Error detection circuit, 38 ... Control circuit, 40 ... Photodetector, 42 _ij ... Light receiving element

Claims (3)

[Claims] 1. A first optical system that generates parallel projection light and extracts red light, green light, and blue light from the projection light, and the red light, the green light, and the blue light, respectively. Through the first optical system, and three liquid crystal display means for transmitting a reference image to generate a reference image, and a beam-shaped reference light beam indicating a reference for the position of each of the three liquid crystal display means.
A reference light beam irradiating means for irradiating a predetermined position of each of the three liquid crystal display means; A positional deviation detecting unit that detects a positional deviation from an actual position, a position correcting unit that corrects the position of each of the three liquid crystal display units so as to cancel each of the detected positional deviations, and the three liquid crystals. A second optical system for synthesizing and projecting the reference images generated by the respective display means. 2. The position correcting means expands and contracts according to temperature to fix each of the liquid crystal display means to a predetermined position, and each of the fixing members based on each of the detected positional deviations. The image projection apparatus according to claim 1, further comprising: a correction unit that changes the temperature of the liquid crystal display device to expand or contract the lengths thereof and corrects the positions of the three liquid crystal display devices. 3. The positional deviation detecting means is provided at predetermined positions of the three liquid crystal display means, respectively, and three light receiving means for respectively converting the received reference light rays into electric signals, and the three light receiving means. Based on each of the electrical signals converted by the three light receiving means provided at a predetermined position of the liquid crystal display means, a positional deviation between the reference position and the actual position of the three liquid crystal display means is calculated. The image projection apparatus according to claim 1, further comprising a detection unit that detects the image.