JPH09282097A - Projection-type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a control instruction based on light beams projected on a screen by means of an optical indication device and to input it to a personal computer. SOLUTION: Since the light beams outputted from the optical indication device 30 are not polarized light, the light beams of the optical indication device 30, which are reflected on the screen 12, pass through a projection lens 24, are separated into two polarized components in a polarized beam splitter 25 and are projected on a liquid crystal display device 23 and a two-dimensional optical sensor 26. The two-dimensional optical sensor 26 converts a projected video into a video signal b1 and supplies it to an indication signal processing circuit 27. The indication signal processing circuit 27 checks to which part of the screen 12 the light beams emitted from the optical indication device 30 are projected based on the video signal b1 of the detection result of the two-dimensional optical sensor 26. The control instruction is generated based on information and it is transmitted to the personal computer 11 as a control signal c1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal display device for displaying image light by projecting image light on a screen,
In particular, it relates to a projection type liquid crystal display device with improved operability.

[0002]

2. Description of the Related Art In recent years, with the increase in definition of liquid crystal panels, it has become possible to project an image of a personal computer by a projection type liquid crystal display device, and it has come to be used for presentations and the like.

FIG. 11 is a block diagram showing a projection system for projecting an image of such a conventional personal computer by a projection type liquid crystal display device.

Reference numeral 201 is a personal computer, and a video signal a9 from the personal computer 201.
Is enlarged and projected on the screen 202 which is projected by the projection type liquid crystal display device 210.

The projection type liquid crystal display device 210 comprises a video signal processing circuit 211, a light source 212, a liquid crystal display unit 213 and a projection lens 214.

The video signal processing circuit 211 performs video signal processing on the video signal a9 from the personal computer 201 and displays it on a liquid crystal display unit 213 composed of a liquid crystal panel and its drive circuit.

The liquid crystal display unit 213 has a video signal a9.
The light from the light source 212 is transmitted while the amount of transmission in the corresponding pixel is controlled based on The light transmitted through the liquid crystal display unit 213 is enlarged and projected on the screen 202 by the projection lens 214.

An operator who gives a presentation performs an operation such as switching of screens. Therefore, an input device 2 such as a mouse is used.
03 was operated to input a control command to the personal computer 201. In this case, the projection type liquid crystal display device 2
In many cases, the distance between the screen 10 and the screen 202 is large.
It is necessary to explain by 02.

Therefore, the personal computer 201
Is placed on the side of the person who gives the presentation, and is connected to the projection type liquid crystal display device 210 with a long cable.
It was necessary to put 01 operators.

[0010]

In the above-mentioned conventional projection type liquid crystal display device, the operator who gives a presentation operates the input device such as a mouse to operate the input device such as a mouse, so that the personal computer is operated. I was entering a control command. In this case, the projection type liquid crystal display device and the screen are often separated from each other, but the person giving the presentation needs to explain by the screen. Therefore, it is necessary to place the personal computer on the side of the person who gives the presentation and connect it to the projection type liquid crystal display device with a long cable, or to place an operator of the personal computer other than the person who gives the presentation.

Therefore, it is an object of the present invention to provide a projection type liquid crystal display device capable of producing a control command based on a light beam projected on a screen by an optical pointing device and inputting the control command into a personal computer.

[0012]

A projection type liquid crystal display device according to claim 1, wherein a light source, at least one liquid crystal display unit for transmitting a light beam from the light source in a state where a transmission amount is controlled, A lens is installed between the liquid crystal display unit and the projection lens, the polarized light transmitted through the liquid crystal display unit passes through, and the non-polarized light incident from the projection lens is directed to the liquid crystal display device and the liquid crystal display. A polarized beam splitter that branches in different directions with respect to the device; and a two-dimensional optical sensor that is disposed at a position that is optically equal to the liquid crystal display unit with respect to the projection lens and that detects a projected image. The position of the pointing light beam projected by the external optical pointing device is detected based on the detection result of the two-dimensional optical sensor, and the control command is generated based on the detection result. Characterized by comprising an indication signal processing circuits to be transmitted to the personal computer Te.

A projection type liquid crystal display device according to a second aspect is the projection type liquid crystal display device according to the first aspect, wherein at least two liquid crystal display units are provided, and one of the liquid crystal display units has a liquid crystal display unit. The polarization beam splitter is provided immediately before the unit, and the wavelength of the light beam projected from the optical pointing device is in the wavelength band of the light beam that the one liquid crystal display unit transmits and projects the light beam from the light source. It is characterized in that it is included.

A projection type liquid crystal display device according to a third aspect is the projection type liquid crystal display device according to any one of the first and second aspects, wherein the polarization beam splitter and the two-dimensional optical sensor are provided between the polarization beam splitter and the two-dimensional optical sensor. It is characterized in that reduction optical means for reducing the image projected by the projection lens is provided.

A projection type liquid crystal display device according to a fourth aspect is the projection type liquid crystal display device according to any one of the first to third aspects, wherein a control signal of the personal computer is modulated by turning on and off an instruction light source. An instruction light source control circuit is provided in the optical pointing device, and the instruction signal processing circuit demodulates the control signal of the personal computer from the output of the two-dimensional optical sensor and transmits the control signal to the personal computer. Characterize.

A projection type liquid crystal display device according to a fifth aspect is the projection type liquid crystal display device according to any one of the first to third aspects, wherein the projection type liquid crystal display device is provided in the optical indicating device, and is provided in the personal computer. Remote control signal transmitting means for modulating and transmitting a control signal to a remote control signal, and remote control signal receiving for receiving the remote control signal, demodulating the control signal of the personal computer, and transmitting the control signal to the personal computer And demodulation means.

According to a sixth aspect of the present invention, there is provided a projection type liquid crystal display device, wherein the optical indicating device is provided in the optical indicating device, and the indicating light source control circuit modulates a control signal of the personal computer by intermittently turning on the indicating light source. Provided are remote control signal transmitting means for modulating the control signal of the personal computer to a remote control signal and transmitting the remote control signal, and remote control signal receiving demodulating means for receiving the remote control signal and demodulating the control signal of the personal computer. The instruction signal processing circuit demodulates the control signal of the personal computer from the output of the two-dimensional optical sensor, and selects a correct signal from the control signal and the signal demodulated by the remote control signal reception demodulation means. And transmit it to the personal computer. Characterized in that it.

According to the present invention, the light beam projected on the screen by the optical pointing device is projected on the two-dimensional optical sensor, and the pointing signal processing circuit detects the two-dimensional optical sensor. Since the position of the pointing light beam projected by the optical pointing device is detected based on the result, the detection result is transmitted to the personal computer.
A control command can be created based on the light beam projected on the screen by the optical pointing device and input to the personal computer.

[0019]

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

FIG. 1 is a block diagram showing a first embodiment of a projection type liquid crystal display device according to the present invention.

In FIG. 1, reference numeral 11 is a personal computer, and a video signal a1 from the personal computer 11 is enlarged and projected on a screen 12 which is projected by a projection type liquid crystal display device 20.

The projection type liquid crystal display device 20 comprises a video signal processing circuit 21, a light source 22, a liquid crystal display unit 23, a projection lens 24, a polarization beam splitter 25, a two-dimensional optical sensor 26 and an instruction signal processing circuit 27. .

The video signal processing circuit 21 performs video signal processing on the video signal a1 from the personal computer 11 and displays it on the liquid crystal display unit 23 including a liquid crystal panel and a drive circuit thereof.

The liquid crystal display unit 23 transmits the light from the light source 22 in a state where the transmission amount in the corresponding pixel is controlled based on the video signal a1. In this case, the light output from the liquid crystal display unit 23 becomes polarized light. The light transmitted through the liquid crystal display unit 23 enters the polarization beam splitter 25. The polarization beam splitter 25 has a 45
The light having the polarization axis of the polarized light output from the liquid crystal display unit 23 is transmitted at the angle of 90 degrees, and the light having the polarization axis different from that by 90 degrees is reflected. The light emitted from the polarization beam splitter 25 is enlarged and projected on the screen 12 by the projection lens 24.

Consider an optical pointing device 30 which gives an instruction by projecting a light beam such as a laser pointer on the screen from the outside. Since the light beam output from the optical pointing device 30 is not polarized, the light beam of the optical pointing device 30 reflected from the screen 12 passes through the projection lens 24 and is separated into two polarization components by the polarization beam splitter 25. The image is projected on the liquid crystal display device 23 and the two-dimensional optical sensor 26. The two-dimensional optical sensor 26 detects a projected image, is composed of an image pickup device such as a CCD, and is arranged at a position optically equal to the liquid crystal display unit 23 with respect to the projection lens 24. , The projected image is converted into an image signal b1 and supplied to the instruction signal processing circuit 27. The instruction signal processing circuit 27 includes the two-dimensional optical sensor 2
Based on the video signal b1 as the detection result of No. 6, it is checked where the light beam emitted from the optical pointing device 30 is projected on the screen 12, a control command is created based on this information, and the control signal c1 is sent to the personal computer 11. To transmit.

The personal computer 11 performs various controls such as video switching based on the control signal c1.

FIG. 2 is an explanatory view showing the liquid crystal display unit 23 of FIG. 1 in detail.

The liquid crystal display unit 23 is a TN type liquid crystal panel and is composed of a first polarizing plate 41, a liquid crystal panel 42, a second polarizing plate 43 and a drive circuit (not shown). Light input to the light source of FIG. 1 is polarized by the first polarizing plate 41 and input to the liquid crystal panel 42.

Since the liquid crystal panel 42 has the property of changing the direction of the polarization axis of the input polarized light by the voltage applied by the drive circuit, the second polarizing plate 43
The transmittance changes according to the applied voltage.
Therefore, the light output from the liquid crystal display unit 23 becomes polarized light.

Since the light output from the liquid crystal display unit 23 passes through the polarization beam splitter 25 as it is, it is possible to obtain almost the same amount of light as when the screen does not have the polarization beam splitter 25.

FIG. 3 is an explanatory diagram showing the operation of the embodiment of the invention shown in FIG. In FIG. 3, the light source and the polarizing panel are omitted for simplification, and the light from the light source enters from the direction indicated by the thick arrow.

In FIG. 3, an image 51 of "ABC" is displayed on the liquid crystal display unit 23. The liquid crystal display unit 23 displaying such an image 51 transmits the light from the light source 22 as polarized light, and the light transmitted through the liquid crystal display unit 23 is transmitted to the screen 12 via the polarization beam splitter 25 and the projection lens 24. The image 52 is enlarged and projected.

In this case, most of the polarized light from the liquid crystal display unit 23 passes through the polarization beam splitter 25.

On the contrary, the light reflected from the screen 12 will be considered. The light reflected from the screen 12 again passes through the projection lens 24 and the polarization beam splitter 25 and enters the liquid crystal display unit 23. At this time,
The optical path of the light reflected by the screen 12 is the same as the optical path projected from the liquid crystal display unit 23 onto the screen 12. Therefore, as long as the image 52 projected on the screen 12 is in focus, the liquid crystal display unit 2
The image formed on the liquid crystal panel 3 (the liquid crystal panel 42 in FIG. 2) is the focal length of the projection lens 24 or the projection lens 24.
The image is exactly the same as the image displayed on the liquid crystal panel of the liquid crystal display unit 23, regardless of the distance between the screen and the screen 12. Further, the light reflected by the screen 12 with its polarization axis changed is reflected by the polarization beam splitter 25 and is incident on the two-dimensional optical sensor 26. Since the two-dimensional optical sensor 26 is optically located at the same position as the liquid crystal panel with respect to the projection lens 24, the screen 1 is displayed on the liquid crystal panel.
The same shape as the image reflected from 2 is projected. Therefore, regardless of the focal length of the projection lens 24 or the distance between the projection lens 24 and the screen 12, the two-dimensional optical sensor 26 projects an image 53 having the same shape as the image 51 displayed by the liquid crystal panel. Become. The screen 12
Then, since most of the light is reflected while keeping the same polarization axis, the amount of light of the image 53 reflected by the two-dimensional optical sensor 26 is small.

On the other hand, let us consider a case where an instruction is given by projecting a light beam on the screen 12 by the optical pointing device 30.

The light from the optical pointing device 30 is displayed on the screen 12 as an image 54. Here, since the light beam output from the optical pointing device 30 is not polarized light, the light of the image 54 reflected from the screen 12 passes through the projection lens 24 and is separated into two polarization components by the polarization beam splitter 25. Images 55 and 56 having similar brightness are projected on the liquid crystal display unit 23 and the two-dimensional optical sensor 26, respectively. Thereby, the two-dimensional optical sensor 26
The image 56 displayed by the optical pointing device 30 is displayed stronger than the image 53 displayed by the liquid crystal display unit 23.

Therefore, based on the signal from the two-dimensional optical sensor 26, the instruction signal processing circuit 27 examines where the light beam emitted from the optical pointing device 32 is projected, and the control instruction is generated based on this information. Control signal c1
As a result, the personal computer 11 can be operated by using the optical pointing device 32.

According to such an embodiment of the invention, a control command can be created based on the light beam projected on the screen by the optical pointing device and input to the personal computer. You can operate the projection-type liquid crystal display device by simply moving the light beam to be projected onto the screen, and when giving a presentation near the screen, place the personal computer on the side of the person giving the presentation and use the long cable to There is no need to connect to a display device or to place an operator of the personal computer other than the person giving the presentation, which is very convenient for the person giving the presentation.

FIG. 4 is a block diagram showing a second embodiment of the projection type liquid crystal display device according to the present invention, which is applied to a three-plate type projection liquid crystal display device.

In FIG. 4, the three-plate projection type liquid crystal display device 60 basically has a structure in which the liquid crystal display means of the single-plate projector shown in FIG. 1 is changed from the single-plate liquid crystal display unit 23 to the three-plate structure. It just changed.

The three-plate projection type liquid crystal display device 60 includes a light source 6
1, a mirror 62, a liquid crystal display unit 70, a polarization beam splitter 63, a projection lens 64, and a two-dimensional optical sensor 65.

The light from the light source 61 is reflected by the total reflection mirror 62 and enters the liquid crystal display means 70.

The liquid crystal display means 70 comprises red (R), green (G) and blue (B) liquid crystal display units 71R, 71G,
71B, separation system dichroic mirrors 72 and 73,
It is composed of total reflection mirrors 74 and 75 and synthetic dichroic mirrors 76 and 77.

The light incident on the liquid crystal display means 70 is separated into two by the separation system dichroic mirror 72, and one of the separated lights is reflected on the total reflection mirror 74 and is incident on the R liquid crystal display unit 71R. It The other light separated by the separation system dichroic mirror 72 is separated into two by the separation system dichroic mirror 73 and is incident on the G and B liquid crystal display units 71G and 71B, respectively.

R, G, B liquid crystal display units 71R, 7
1G and 71B allow incident light to be transmitted in a state where the amount of transmission in the corresponding pixel is controlled based on the R, G, and B video signals from the video signal processing circuit. The light output from the R, G, B liquid crystal display units 71R, 71G, 71B becomes polarized light. R and G liquid crystal display units 71R,
The R and G lights output from 71G are combined by the combining dichroic mirror 76 and enter the combining dichroic mirror 77 as combined R and G lights. The B light output from the B liquid crystal display unit 71B is reflected by the total reflection mirror 75 and is combined with the dichroic mirror 77.
Incident on. The combining dichroic mirror 77 combines the incident R and G combined lights and the incident B light, and makes them incident on the polarization beam splitter 63 as color image light. The polarization beam splitter 63 transmits light having a polarization axis of polarization output from the liquid crystal display unit 70, and reflects light having a polarization axis different from that by 90 degrees. The light emitted from the polarization beam splitter 63 is enlarged and projected on the screen by the projection lens 64. Light from the optical pointing device reflected from the screen passes through the projection lens 64, is separated into two polarization components by the polarization beam splitter 63, enters the liquid crystal display means 70, and is projected on the two-dimensional optical sensor 65. It Here, in the embodiment of the present invention, the projection lens 64 and the R, G, B liquid crystal display units 71R, 71
Since the distance between the G and 71B liquid crystal panels is longer than the distance between the projection lens 24 and the liquid crystal panel of the liquid crystal display unit 23 shown in FIGS. 1 to 3, the polarization beam splitter 63 and the two-dimensional optical sensor 65 are Is also getting longer.

According to the embodiment of the second invention, the same effect as that of the embodiment of the invention of FIG. 1 can be obtained in the three-plate projection type liquid crystal display device.

FIG. 5 is a block diagram showing a third embodiment of the projection type liquid crystal display device according to the present invention.
The same components as those of the embodiment of the present invention are denoted by the same reference numerals, and description thereof is omitted.

5, in the embodiment of the present invention, in the liquid crystal display means 79, one total reflection mirror 75 of the embodiment of the invention shown in FIG.
, And the two-dimensional optical sensor 65 is placed at the same position as the B liquid crystal panel 71B.

The light incident on the polarization beam splitter 63 from the projection lens 64 is only the light for the B liquid crystal panel 71B due to the function of the synthesizing dichroic mirror 77. Therefore, it is necessary to match the wavelength band of the B liquid crystal panel 71B with the wavelength band of the light beam emitted from the optical pointing device. When the rays emitted from the optical pointing device are to be used for red and green rays, the separation dichroic mirror 7
2, 73, the polarization beam splitter 63, and the composition type dichroic mirrors 76, 77 are changed, and R, G, B liquid crystal display units 71R, 71G, 71B are changed.
Must be exchanged and the two-dimensional optical sensor 65 must be configured so that the light beam emitted from the optical pointing device arrives.

According to such an embodiment of the present invention,
The projection type liquid crystal display device can be made smaller than that of the embodiment of the present invention shown in FIG.

FIG. 6 is a block diagram showing a fourth embodiment of the projection type liquid crystal display device according to the present invention.
The same components as those of the projection type liquid crystal display device are attached with the same notations and an explanation thereof is omitted.

6, in the projection type liquid crystal display device 80 of the embodiment of the present invention, instead of the two-dimensional optical sensor 26 having the same size as the liquid crystal panel of the liquid crystal display unit shown in FIGS. 1 to 3, A reduction optical unit 81 and a two-dimensional optical sensor 82 smaller than the liquid crystal panel are used.

In the embodiments of the first to third inventions shown in FIGS. 1 to 5, it is necessary to use the two-dimensional optical sensor having the same size as the liquid crystal panel. Generally, a CCD or the like is used for the two-dimensional optical sensor, but its size is much smaller than the liquid crystal panel. Therefore, in the embodiment of the present invention, the reduction optical unit 81 divides the image projected on the two-dimensional optical sensor 82 into a fraction.
The size is reduced to. By using this reduction optical unit 81, it is smaller than a liquid crystal panel.
A dimensional optical sensor 82 can be used. The reduction optical unit 81 and the small two-dimensional optical sensor 82 are three
It can also be used for plate projection type liquid crystal display devices.

FIG. 7 is a block diagram showing a fifth embodiment of the projection type liquid crystal display device according to the present invention.
The same components as those of the projection type liquid crystal display device are attached with the same notations and an explanation thereof is omitted.

Generally, an instruction device for operating a computer is provided with a portion for moving a cursor on the screen, such as a mouse, and one to three switches for inputting a command. In the embodiment of the present invention,
The optical pointing device 90 is provided with a personal computer controlling switch 91 for command input. When this switch 91 is pressed, the pointing light source control circuit 92 controls ON / OFF of the pointing light source 93, and the screen is displayed. 1
A command (control signal of the personal computer 99) is transmitted by modulating ON / OFF of the light projected on the screen 2. On the other hand, the instruction signal processing circuit 97 analyzes the position information instructed by the optical instruction device 90 and the command by the personal computer control switch 91 based on the video signal b1 from the two-dimensional optical sensor 26, and the analysis result is The instruction signal c2 is transmitted to the personal computer 99. The personal computer 99 performs various controls such as video switching based on the instruction signal c1.

With the above configuration, it becomes possible to operate the personal computer like a mouse using the optical pointing device 90.

FIG. 8 is a block diagram showing a sixth embodiment of the projection type liquid crystal display device according to the present invention.
The same components as those of the projection type liquid crystal display device are attached with the same notations and an explanation thereof is omitted.

In FIG. 8, in the embodiment of the sixth invention, a personal computer control switch 102,
The projection type liquid crystal display device control switch 103 and the remote control light emission control circuit 104 constitute remote control signal transmission means for modulating the control signal of the personal computer 124 into a remote control signal and transmitting the modulated remote control signal.

The light receiving circuit 121 and the remote control control circuit 122 receive a remote control signal, demodulate the control signal of the personal computer 124, and output this control signal to the personal computer 124.
It constitutes a remote control signal receiving and demodulating means for transmitting to.

A normal liquid crystal remote controller 101 and an optical pointing device 110 are integrated into the pointing device 100. The command of the personal computer control switch 102 is modulated by the remote control light emission control circuit 104 together with the signal from the projection type liquid crystal display control switch 103, and a part of the normal infrared remote control signal is modulated by the light emission circuit 105. Is transmitted as. The remote control signal is converted into an electric signal by the light receiving circuit 121 of the projection type liquid crystal display device 120,
It is demodulated by the remote control control circuit 122. The remote control control circuit 122 controls the video signal processing circuit 123 and the like when a command for controlling the projection type liquid crystal display device is sent, and processes an instruction signal when a command for controlling the personal computer is sent. The control command is superimposed on the position information from the circuit 27 and transmitted to the personal computer 124. The configuration of the projection liquid crystal display device 120 other than this is the same as that of the projection liquid crystal display device 20 of FIG.

According to such an embodiment of the present invention,
The same effect as the embodiment of the present invention shown in FIG. 7 can be obtained.

9 and 10 are block diagrams showing a seventh embodiment of the projection type liquid crystal display device according to the present invention. FIG. 9 shows a case where the projection type liquid crystal display device is arranged in front of the screen. FIG. 10 shows a case where the pointing device is arranged on the back side of the screen.

In FIG. 9, in the pointing device 130, the command of the personal computer control switch 131 is sent to both the remote control light emission control circuit 133 and the pointing light source control circuit 134 together with the signal from the projection type liquid crystal display device control switch 132. Is transmitted. Therefore, the control signal of the personal computer 151 and the projection type liquid crystal display device 14
The control signal of 0 is transmitted by both the light beam projected from the pointing light source 135 and the infrared light emitted from the remote control light emitting circuit 136. On the other hand, in the main body of the projection type liquid crystal display device 140, the remote control light receiving circuit 141 is used to control the remote control light emitting circuit 1.
The two-dimensional optical sensor 26 receives the signal from the pointing light source 135, and the two-dimensional optical sensor 26 receives the signal from the pointing light source 135. The respective reception signals are demodulated by the remote control control circuit 142 and the instruction signal control circuit 143, and the signals sent by exchanging signals with each other are used to transmit the video signal processing circuit 144 of the projection type liquid crystal display device 140 and the personal computer. Compute 15
1 is controlled.

With such a configuration, the remote control light emitting circuit 136 is used, for example, when the light from the projection type liquid crystal display device 130 is projected on the screen 12 from the back surface as shown in FIG.
Even if the infrared signal from the optical display device 130 does not easily reach the display device display device 130, remote control can be performed by projecting the light beam from the optical display device 130 onto the screen 12.

The embodiments of the invention shown in FIGS. 7 to 10 are applied to a projection type liquid crystal display device using a two-dimensional optical sensor of a single plate type and having the same size as the liquid crystal panel of the liquid crystal display unit. The present invention may be applied to the three-plate projection type liquid crystal display device shown in FIGS. 4 and 5, or may be applied to the one using the reduction optical unit and the small two-dimensional optical sensor shown in FIG.

[0066]

As described above, according to the present invention, a control command can be created based on the light beam projected on the screen by the optical pointing device and input to the personal computer. You can operate the projection-type liquid crystal display device by simply moving the light beam to be projected onto the screen, and when giving a presentation near the screen, place the personal computer on the side of the person giving the presentation and use the long cable to There is no need to connect to a display device or to place an operator of the personal computer other than the person giving the presentation, which is very convenient for the person giving the presentation.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a first invention of a projection type liquid crystal display device according to the present invention.

FIG. 2 is an explanatory diagram showing the liquid crystal display unit of FIG. 1 in detail.

FIG. 3 is an explanatory diagram showing an operation of the embodiment of the invention shown in FIG.

FIG. 4 is a block diagram showing a second embodiment of a projection type liquid crystal display device according to the present invention.

FIG. 5 is a block diagram showing an embodiment of a third invention of the projection type liquid crystal display device according to the present invention.

FIG. 6 is a block diagram showing an embodiment of a fourth invention of a projection type liquid crystal display device according to the present invention.

FIG. 7 is a block diagram showing a fifth embodiment of a projection type liquid crystal display device according to the present invention.

FIG. 8 is a block diagram showing an embodiment of a sixth invention of the projection type liquid crystal display device according to the invention.

FIG. 9 is a block diagram of the projection type liquid crystal display device according to the seventh embodiment of the present invention, in which the projection type liquid crystal display device is arranged on the front side of the screen.

FIG. 10 is a block diagram of a projection type liquid crystal display device according to an eighth embodiment of the present invention, in which the projection type liquid crystal display device is arranged on the back side of the screen.

FIG. 11 is a block diagram showing a conventional projection system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Projection liquid crystal display device 11 Personal computer 12 Screen 20 Projection liquid crystal display device 21 Video signal processing circuit 22 Light source 23 Liquid crystal display unit 24 Projection lens 25 Polarizing beam splitter 26 Two-dimensional optical sensor 27 Instruction signal processing circuit

Claims (6)

[Claims] 1. A light source, at least one liquid crystal display unit that transmits a light beam from the light source in a state in which the amount of transmission is controlled, a projection lens, and is installed between the liquid crystal display unit and the projection lens. A polarized beam splitter that splits the polarized light that has passed through the liquid crystal display unit and that has entered the projection lens and is not polarized light into a different direction with respect to the liquid crystal display device and the liquid crystal display device. A two-dimensional optical sensor disposed at a position optically equal to the liquid crystal display unit with respect to the projection lens and detecting a projected image, and an external optical instruction based on the detection result of the two-dimensional optical sensor. Detecting the position of the pointing beam projected by the device,
A projection-type liquid crystal display device, comprising: an instruction signal processing circuit that creates a control command based on the detection result and transmits the control command to a personal computer. 2. At least two liquid crystal display units are provided, the polarization beam splitter is provided immediately before one of the liquid crystal display units, and the one liquid crystal display unit is the light source. 2. The projection type liquid crystal display device according to claim 1, wherein the wavelength band of the light beam which is transmitted and projected from is included in the wavelength band of the light beam which is projected from the optical indicating device. 3. A reduction optical unit for reducing an image projected by a projection lens is provided between the polarized beam splitter and the two-dimensional optical sensor. Projection type liquid crystal display device according to item 1. 4. An instruction light source control circuit for modulating a control signal of the personal computer by intermittently emitting an instruction light source is provided in the optical instruction device, and the instruction signal processing circuit outputs the output of the two-dimensional optical sensor to the personal computer. 4. The projection type liquid crystal display device according to claim 1, wherein the control signal is demodulated and the control signal is transmitted to the personal computer. 5. A remote control signal transmitting means which is provided in the optical indicating device and which modulates a control signal of the personal computer into a remote control signal and transmits the remote control signal, and a control signal of the personal computer which receives the remote control signal. 4. The projection type liquid crystal display device according to claim 1, further comprising: a remote control signal reception demodulation unit that demodulates the control signal and transmits the control signal to the personal computer. 6. An instruction light source control circuit, which is provided in the optical indicating device and modulates a control signal of the personal computer by intermittently turning on and off an indicating light source, and a control signal of the personal computer provided in the optical indicating device. Remote control signal transmitting means for modulating and transmitting to a remote control signal, and remote control signal receiving demodulating means for receiving the remote control signal and demodulating the control signal of the personal computer. Demodulating a control signal of the personal computer from the output of the two-dimensional optical sensor, selecting a correct signal from the control signal and the signal demodulated by the remote control signal receiving demodulating means, and transmitting the selected signal to the personal computer. Claim 1 No 4. The projection type liquid crystal display device according to any one of items 3 to 3.