JPH0546109A - Display system and control method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the manufacturing cost, improve the reliability, and simplify the constituent circuit of the electronic control device for controlling the light control element of the spatial light modulator. A one-dimensional light modulator 2 in which a plurality of light control elements 1 are linearly arranged, and one-dimensional modulated light from the one-dimensional light modulator 2 are deflected to make a one-dimensional light modulation on a screen 3. An image based on the image signal is sequentially formed on the screen 3 line by line by the optical scanning device 4 that scans in a direction perpendicular to the length direction of the device 2. By making the one scanning time shorter than one cycle of the critical flicker frequency of the human eye, the difference of the light amount on the screen due to the difference of the operating time of each light control element 1 is changed by the human eye. It is possible to recognize the difference in the brightness of the pixel. Thus, by using the one-dimensional light modulator 2 in which the number of the light control elements 1 is significantly smaller than that of the two-dimensional light modulator,
The purpose can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a spatial light modulator,
The present invention relates to a display system that displays a video signal as a visible image on a screen, and a control method thereof.

[0002]

2. Description of the Related Art A display system using a CRT or a liquid crystal is generally used as a display system for displaying a video signal as a visible image. A larger screen size has been required for this display system. However, a display system using a CRT or a liquid crystal cannot be manufactured with such a large screen size in terms of cost and structure.

Therefore, recently, a display system having a screen size larger than that using a CRT or a liquid crystal has been realized by using a spatial light modulator.

FIG. 6 is a schematic configuration diagram showing a conventional example of a display system using this spatial light modulator (see Japanese Patent Laid-Open No. 3-40693).

As shown in the figure, in this display system, a two-dimensional light modulator 52, which is formed by arranging a large number of light control elements 51 in a plane, is arranged as a spatial light modulator. Each light control element 51 of the two-dimensional light modulator 52 is controlled by the electronic control device 53, and reflects the incident light in a specific direction and deflects it.

Further, as an optical system, a light source 54 and a concave mirror 55 are provided.
The three condenser lenses 56, the plane mirror 57, and the projection lens 58 are arranged, and the screen 59 is further arranged.

In the above structure, the concave mirror 55 efficiently reflects the light L-11 generated by the light source 54 by the condenser lens 56.
Then, the condenser lens 56 converts the light L-11 into a substantially parallel light beam L-12. The plane mirror 57 reflects the light beam L-12 from the light source 54 and makes it enter the two-dimensional light modulator 52.

Each light control element 5 of the two-dimensional light modulator 52
1 individually deflects the incident light flux L-12 toward the projection lens 58 under the control of the electronic control unit 53. In other words, this two-dimensional light modulator 52 is composed of individual light control elements 51.
The light flux L-12 is deflected by
12 will be modulated. And the projection lens 58
The modulated light from the two-dimensional light modulator 52 composed of the deflected beam L-13 from the light control element 51 is imaged on the screen 59.

FIG. 7 is a block diagram showing the configuration of the electronic control unit 53.

As shown in the figure, in the electronic control unit 53, the T
An analog video signal from a signal source 61 such as a V tuner is converted into a digital code by an A / D (analog / digital) converter 71, and the digital code is stored in a buffer memory 72. This digital code represents the address and brightness of each pixel forming the image. If the input video signal is a digital signal from a computer or the like, the digital video signal is sent directly to the buffer memory 72 and stored as a digital code.

Further, the digital code in the buffer memory 72 is decoded by the CPU 73 and stored in the video memory 74 as video data. In some cases, the video data can be transferred to the CPU 73
It is modified according to a program in 73 or an instruction from the outside and then stored in the video memory 74.

Then, the image data in the video memory 74 is sent to each light control element 51 of the two-dimensional light modulator 52 via the shift register latch 75, and the two-dimensional light modulator 5 is transmitted.
2 modulates the luminous flux L-12 from the light source 54.

According to the display system having the above structure, the light control element 51 of the two-dimensional light modulator 52 is controlled by the electronic control unit 53 on the basis of the video signal to modulate the light flux L-12 from the light source 54. Thus, the video signal can be displayed as a visible image on the screen 59 in a large size by enlarging the shape of the two-dimensional light modulator 52.

[0014]

However, since the two-dimensional light modulator 52 used in the conventional display system is formed by arranging a large number of light control elements 51 in a plane, The defective element that does not operate normally is included at a high rate, and the yield is low to obtain a perfect two-dimensional optical modulator 52. Therefore, in the conventional display system, the unit cost of the two-dimensional light modulator 52 is high, the manufacturing cost of the system is high, and the reliability is low.

Further, the electronic control device 53 for controlling the large number of light control elements 51 of the two-dimensional light modulator 52 has a problem in that its constituent circuit becomes complicated and the device itself becomes large.

The present invention has been made in order to solve these problems, and has a structure of an electronic control device for controlling the light control element of the spatial light modulator, which has a low manufacturing cost and high reliability. An object of the present invention is to provide a display system having a simplified circuit and a control method thereof.

[0017]

In order to achieve the above object, in the display system according to the present invention, a one-dimensional light modulator formed by arranging a plurality of light control elements in a line is arranged as a spatial light modulator. At the same time, an optical scanning device is arranged which deflects the one-dimensional modulated light from the one-dimensional light modulator and scans the screen in a direction perpendicular to the length direction of the one-dimensional light modulator.

As a control method of this display system, the scanning cycle of the optical scanning device is set shorter than one cycle of the critical flicker frequency of human eyes.

[0019]

In the display system having the above construction, the image based on the image signal is sequentially formed on the screen line by line by the one-dimensional light modulator and the optical scanning device. And by making the scanning time of one time shorter than one cycle of the critical flicker frequency of the human eye, the difference in the amount of light on the screen due to the difference in the operating time of each light control element,
It is possible for the human eye to recognize the difference in the brightness of each pixel. Therefore, by the configuration of this display system and the control method thereof, the video signal can be displayed large on the screen as a two-dimensional visible image.

[0020]

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

FIG. 1 is a schematic configuration diagram of a display system in an embodiment of the present invention. As shown in the figure, the feature of this display system is that a spatial light modulator is provided with a one-dimensional light modulator 2 formed by arranging a plurality of light control elements 1 in a straight line. Of the one-dimensional light modulator 2 by deflecting the modulated light of
The optical scanning device 4 for scanning in the direction perpendicular to the length direction of the optical disc is arranged.

As another configuration, an electronic control unit 5 for controlling the light control element 1 of the one-dimensional light modulator 2 is provided, and a light source 6, a concave mirror 7 and three condenser lenses 8 are provided as an optical system. And the projection lens 9 is arranged.

The one-dimensional light modulator 2 includes an electronic control unit 5
Each light control element 1 controlled by is a deformable mirror type that reflects and deflects incident light in a specific direction. This type of spatial light modulator is disclosed in US Pat. Nos. 4,441,791, 4,710,732 and 45,
No. 96992, No. 4615595, No. 46627
46 and 168724.

As shown in the perspective views of FIGS. 1 and 2, the optical scanning device 4 includes a plurality of reflecting planes 10 of the same size.
And a rotary mirror 11 having an axis 1
It is composed of a motor 13 for rotating around 2. The rotating mirror 11 is arranged on the optical path between the one-dimensional light modulator 2 and the projection lens 9 with its axis 12 parallel to the one-dimensional light modulator 2. In this example,
The rotating mirror 11 is a regular hexagonal prism, and has six reflecting planes 10.
Is equipped with. Regarding the shape of the rotating mirror 11,
Not limited to the regular hexagonal prism, a regular triangular prism having three reflection planes 10 as shown in the perspective view of FIG.
As shown in the perspective view of (B), it may have a plate shape having two reflecting flat surfaces 10. Further, instead of the rotating mirror 11,
It is also possible to use a columnar rotating prism, in which case the light from the one-dimensional light modulator 2 will be deflected by refraction.

In the above structure, the light L- emitted from the light source 6
When the concave mirror 7 efficiently makes 1 enter the condenser lens 8, the condenser lens 8 makes the light L-1 into a substantially parallel light beam L-2 and makes it enter the one-dimensional light modulator 2.

Each light control element 1 of the one-dimensional light modulator 2 individually enters the incident light beam L-2 under the control of the electronic control unit 5.
Is deflected toward the rotating mirror 11 of the optical scanning device 4. That is, the one-dimensional light modulator 2 modulates the light flux L-2 by deflecting the light flux L-2 by each light control element 1.

The rotating mirror 11 reflects the deflected beam L-3 from the light control element 1 on any one of the reflecting planes 10 and deflects it toward the projection lens 9. Then, the projection lens 9 forms an image on the screen 3 of the one-dimensional modulated light from the one-dimensional light modulator 2 composed of the deflected beam L-3. At this time, the one-dimensional modulated light is linearly imaged on the screen 3 corresponding to the shape of the one-dimensional light modulator 2.

Further, when the motor 13 rotates the rotating mirror 11 in a fixed direction, the rotating mirror 11 changes the deflection direction of the deflected beam L-3 from the light control element 1,
The one-dimensional modulated light from the one-dimensional light modulator 2 is transmitted to the screen 3
The top is scanned in a direction perpendicular to the length direction of the one-dimensional light modulator 2. Moreover, the rotating mirror 11 has the respective reflecting planes 1
Since the deflected beam L-3 is reflected one after another at 0, the one-dimensional modulated light repeatedly scans the screen 3 in a fixed direction according to the rotating direction of the rotating mirror 11.

FIG. 4 is a block diagram showing the configuration of the electronic control unit 5.

As shown in the figure, this electronic control unit 5 has an A / D
(Analog / digital) converter 21, buffer memory 22, CPU 23, S / P (serial / parallel) converter 24, shift register latch 25
And a pulse width generator 26. The pulse width generator 26 can be incorporated in the CPU 23.

In this electronic control unit 5, the analog video signal from the signal source 31 such as a TV tuner is converted into a digital code by the A / D converter 21, and the digital code is stored in the buffer memory 22. This digital code represents the address and brightness of each pixel forming the image. If the input video signal is a digital signal from a computer or the like, the digital video signal is sent directly to the buffer memory 22 and stored as a digital code.

Next, the digital code in the buffer memory 22 is decoded by the CPU 23 and sent to the S / P converter 24 as video data. In some cases, the video data is sent to the CPU 23 in the CPU 2
It is modified according to the program in 3 or an instruction from the outside and then sent to the S / P converter 24.

Subsequently, the video data from the CPU 23 is converted into S
/ P converter 24 divides each address,
The divided data is sent to the shift register latch 25 via the bus 27. The shift register latch 25
Then, when the data of the address corresponding to one line of the image is prepared, the data for one line is sent to the pulse width generator 26 in accordance with the synchronizing signal from the CPU 23, and the data having the pulse width corresponding to the brightness of each address is sent. The data signal of each address is converted to a signal and is sent to each light control element 1 of the one-dimensional light modulator 2 in accordance with the synchronization signal. With this data signal, the operating time of each light control element 1, that is, the time for deflecting the light beam L-2 from the light source 6 toward the rotating mirror 11 of the optical scanning device 4 is controlled according to the brightness of each pixel, The light flux L-2 from the light source 6 is modulated.

Then, a data signal for each line of the image is sent to the light control element 1 of the one-dimensional light modulator 2 and the luminous flux L-
2 is modulated, and at the same time, scanning is performed by the optical scanning device 4.

At that time, the scanning cycle of the optical scanning device 4 is controlled to be shorter than the critical flicker frequency of human eyes, that is, one cycle of the maximum frequency at which blinking of light can be recognized. By this control, each light control element 1 described above
It is possible for the human eye to recognize the difference in the amount of light on the screen 3 due to the difference in the operating time of 1 as a difference in the brightness of each pixel, and to display a flicker-free image. Of course, the light control element 1 of the one-dimensional light modulator 2 can operate at a sufficient speed in response to such control.

That is, according to the configuration and control method of this display system, the one-dimensional light modulator 2 and the optical scanning device 4 sequentially form an image based on the image signal line by line, and the scanning is performed once. By making the time shorter than one cycle of the critical flicker frequency of human eyes, the video signal is displayed large on the screen 3 as a two-dimensional visible image.

According to this display system, since the one-dimensional light modulator 2 having a significantly smaller number of light control elements than the two-dimensional light modulator is used as the spatial light modulator, the number of the light control elements 1 is increased. And a complete one-dimensional optical modulator 2 without any defective light control element 1 can be obtained with high yield, so that the cost of the spatial light modulator can be significantly reduced and the reliability can be improved. Can also be improved.

Further, the constituent circuit of the electronic control unit 5 for controlling the light control element 1 of the one-dimensional light modulator 2 can be greatly simplified as compared with the case of the two-dimensional light modulator, and thus the electronic component The control device 5 can also be reduced in cost and downsized. The cost reduction effect of the one-dimensional light modulator 2 and the electronic control device 5 can be sufficiently obtained even if the optical scanning device 4 having a simple structure is added.

Next, as another embodiment of the present invention, a method of displaying a color image using the above display system will be described.

In order to colorize the above display system, filters for the one-dimensional modulated light from the one-dimensional light modulator 2 corresponding to three colors of red (R), green (G) and blue (B) are used. A wavelength selecting means for sequentially transmitting light may be added.

As the wavelength selecting means, for example, as shown in the explanatory view of FIG. 5, the rotating mirror 11 of the optical scanning device 4 is used.
R, G, B optical filters RF, G on the reflection plane 10 of
Attach the same number of F and BF in a fixed order. Therefore, in this case, as the rotating mirror 11, one having the number of reflection planes 10 that is an integral multiple of 3 is used. When using the optical filters RF, GF, and BF in this way, a white light source such as a halogen bulb is used as the light source 6.

Then, the electronic control unit 5 controls the signal source 31.
The video signal from the video signal is divided into R, G, and B signals for each screen based on the color information included in the video signal.
The light control element 1 of the one-dimensional light modulator 2 is controlled by the G and B signals as described above. The control is performed by the rotating mirror 11
By synchronizing with the scanning by each reflection plane 10 and corresponding to the optical filters RF, GF, and BF of each color, a color image can be displayed on the screen 3. Also in this case, the scanning cycle of the optical scanning device 4 is set shorter than one cycle of the critical flicker frequency of human eyes.

In addition, the light source 6 is composed of three light sources such as LEDs which emit light of wavelengths corresponding to the three colors of R, G and B, and the light sources of the three colors are sequentially switched to emit light. Good. Even if such three color light sources are used, a color image can be displayed as in the case of using the optical filters RF, GF and BF.

In the above colorized or non-colored display system, the one-dimensional modulated light from the one-dimensional light modulator 2 is intermittently supplied to the screen 3 for each line of an image formed by the one-dimensional light modulator 2. By controlling so as to form an image on the upper side, the lines are more clearly separated from each other, and blurring does not occur at the boundary between the lines, and as a result, the image can be displayed more clearly on the screen 3. it can. Further, it is not necessary to irradiate the screen 3 with extra light during the flyback period from the final line to the return to the first line.

In order to form an image of the one-dimensional modulated light intermittently in this way, for example, the light emission of the light source 6 may be pulsed or a high-speed shutter may be arranged in the optical path from the light source 6 to the screen 3. Alternatively, a step motor may be used as the motor 13 for rotating the rotary mirror 11 of the optical scanning device 4, and the rotary mirror 11 may be intermittently rotated every scanning of one line.

Further, in the above-mentioned colorized or non-colored display system, the scanning speed of the optical scanning device 4 is controlled to be changed, that is, the rotational speed of the rotary mirror 11 by the motor 13 in the above embodiment. By changing the length, the length of the image displayed on the screen 3 in the scanning direction can be changed to easily and steplessly change the aspect ratio (aspect ratio) of the image. However, when the rotation speed of the rotating mirror 11 is increased to extend the length of the image in the scanning direction, the shape of the rotating mirror 11 and the size of the reflection plane 10 thereof are appropriately designed according to the length. I need to leave. In conventional display systems, this aspect ratio is determined by the arrangement of the light control elements of the two-dimensional light modulator.

[0047]

As described above, according to the display system and the control method thereof according to the present invention, an inexpensive one-dimensional light modulator and an optical scanning device are used, and a video signal is displayed on the screen as a two-dimensional visible image. Can be displayed. As a result, it is possible to reduce the manufacturing cost of the display system using the spatial light modulator, simplify the configuration circuit of the electronic control device that controls the light control element of the spatial light modulator, and downsize the electronic control device. You can

Further, it is possible to colorize by using a wavelength selection means or a light source corresponding to three colors of red, green and blue. Furthermore, the aspect ratio of the displayed image can be easily and steplessly changed. Will also be possible.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a display system according to an embodiment of the present invention.

FIG. 2 is a perspective view of an optical scanning device according to an embodiment of the present invention.

3A and 3B are perspective views showing another example of a rotating mirror of an optical scanning device.

FIG. 4 is a block diagram showing a configuration of an electronic control device according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram of wavelength switching means in another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a display system in a conventional example.

FIG. 7 is a block diagram showing a configuration of an electronic control device in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light control element 2 One-dimensional light modulator 3 Screen 4 Optical scanning device 5 Electronic control device 6 Light source 9 Projection lens 11 Rotating mirror (optical scanning device) 13 Motor (optical scanning device) 31 Signal source RF, GF, BF Optical filter (Wavelength switching means)

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[Procedure amendment]

[Submission date] January 22, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

[0019]

In the display system having the above construction, the image based on the image signal is sequentially formed on the screen line by line by the one-dimensional light modulator and the optical scanning device. Then, by making the vertical scanning time shorter than one cycle of the critical flicker frequency of the human eye, the afterimage effect of the human eye is reduced.
The result is perceived as a full-screen image. Furthermore, one line
Within the scanning period, the light intensity difference between on the screen due to a difference in operating time of the light control element, to the human eye, and can be recognized as a difference or gradation of brightness of each pixel (contrast) Become. Therefore, by the configuration of this display system and the control method thereof, the video signal can be displayed large on the screen as a two-dimensional visible image.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction content]

As shown in the perspective views of FIGS. 1 and 2, the optical scanning device 4 includes a plurality of reflecting planes 10 of the same size.
And a rotary mirror 11 having an axis 1
It is composed of a motor 13 for rotating around 2. The rotating mirror 11 is arranged on the optical path between the one-dimensional light modulator 2 and the projection lens 9 with its axis 12 parallel to the one-dimensional light modulator 2. In this example,
The rotating mirror 11 is a regular hexagonal prism, and has six reflecting planes 10.
Is equipped with. Regarding the shape of the rotating mirror 11,
Is not limited to the regular hexagonal prism, it may be a regular triangular prism having a reflecting plane 10 of the three-sided as shown in the perspective view of FIG. 3 (A), further
May be a regular polygonal prism having seven or more faces . Further, instead of the rotating mirror 11, it is also possible to use a columnar rotating prism, in which case the light from the one-dimensional light modulator 2 is deflected by refraction.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

At that time, the scanning cycle of the optical scanning device 4 is controlled to be shorter than the critical flicker frequency of human eyes, that is, one cycle of the maximum frequency at which blinking of light can be recognized. By this control, each light control element 1 described above
It is possible for the human eye to recognize the difference in the amount of light on the screen 3 due to the difference in the operating time of 1 as a difference in the brightness of each pixel, and to display a flicker-free image. Of course, the light control element 1 of the one-dimensional light modulator 2 can operate at a sufficient speed in response to such control. In the above description, each light control element 1 is
Corresponding to one pixel of digitized video signal
However, the contrast ratio of each light control element 1 is further increased.
If you want to increase the operation time or the operation time (when scanning one line
Interval) is short, and the contrast is sufficient at the same operating speed.
If it is not enough, one pixel of the video signal is controlled by multiple light control
It may be considered that the element 1 is used. In this case, each light system
High resolution and high contrast by reducing the size of the control element
You can get a video of

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

As the wavelength selecting means, for example, as shown in the explanatory view of FIG. 5, the rotating mirror 11 of the optical scanning device 4 is used.
R, G, B optical filters RF, G on the reflection plane 10 of
F, Fit the the BF in a certain order. Or optical filter RF as octopus, GF, in the case of using BF, the light source 6
Use a white light source such as a halogen bulb.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

Then, the electronic control unit 5 controls the signal source 31.
The video signal from the video signal is divided into R, G, and B signals for each screen based on the color information included in the video signal.
The light control element 1 of the one-dimensional light modulator 2 is controlled by the G and B signals as described above. The control is performed by the rotating mirror 11
By synchronizing with the scanning by each reflection plane 10 and corresponding to the optical filters RF, GF, and BF of each color, a color image can be displayed on the screen 3. Also in this case, R by the optical scanning device 4 ,
The time for presenting the three screens G and B is shorter than one cycle of the critical flicker frequency of the human eye.

Claims (6)

[Claims] 1. A spatial light modulator for modulating light from a light source by a light control element, an electronic control device for controlling the light control element of the spatial light modulator based on a video signal from a signal source, and the space. In a display system that includes a projection lens that forms an image of modulated light from an optical modulator on a screen, and that displays the video signal as a visible image on the screen, a plurality of light control elements are provided as the spatial light modulator. The one-dimensional light modulators arranged in a straight line are arranged, and the one-dimensional modulated light from the one-dimensional light modulator is deflected,
A display system, wherein an optical scanning device for scanning the screen in a direction perpendicular to a length direction of the one-dimensional light modulator is arranged. 2. A wavelength selecting means for selectively selectively transmitting the one-dimensional modulated light from the one-dimensional light modulator through filters respectively corresponding to three colors of red, green and blue is added. The display system according to claim 1. 3. The display system according to claim 1, wherein the light source comprises a red light source that emits red light, a green light source that emits green light, and a blue light source that emits blue light. 4. The display system according to claim 1, 2, or 3, wherein a scanning cycle of the optical scanning device is shorter than one cycle of a critical flicker frequency of human eyes. Display system control method. 5. The display system according to claim 1, claim 2, or claim 3, wherein the one-dimensional modulated light from the one-dimensional light modulator is provided for each line of an image formed by the one-dimensional light modulator. A method for controlling a display system, which comprises intermittently forming an image on a screen. 6. The display system control method according to claim 1, wherein the scanning speed of the optical scanning device is changed.