JPH09318923A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically correct inclination in a horizontal direction in the case of setting and to facilitate adjustment operation. SOLUTION: A dichroic mirror 5, and spatial optical modulation elements 6B, 6G, and 6R are integrated to be an optical block 21. The block 21 is turnably held around the optical axis L2 of a projection optical system 7, and the inclination in the horizontal direction is automatically corrected by an automatic balancing mechanism 22. The mechanism 22 is provided with a level vial sensor 24 detecting the inclination with respect to the gravity direction of the block 21, a step motor 23 turning the block 21, and an image position controlling part 25 for driving and controlling the motor 23 by a signal from the sensor 24, etc. The part 25 drives and controls the motor 23 and a liquid crystal driver 27 by the signal from a vertically long and long sideways screen switching switch 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector for enlarging and projecting image light on a screen to display a projected image.

[0002]

2. Description of the Related Art A liquid crystal projector of this type using a liquid crystal panel as a spatial light modulating element is provided with a light source for irradiating the spatial light modulating element regardless of whether it is a rear projection type or a front projection type. As the light source, a xenon lamp, a halogen lamp, a metal halide lamp, etc. are generally used.

FIG. 4 is a schematic configuration diagram showing a conventional example in which such a liquid crystal projector is applied to a color liquid crystal projector. This liquid crystal projector includes a light source 2 in a housing 1,
A relay optical system 3, a polarization beam splitter 4, a cross dichroic mirror 5, a reflective spatial light modulator 6B,
6G, 6R, the projection optical system 7, a power source (not shown), a drive circuit for the spatial light modulators 6B, 6G, 6R, etc. are housed.
The light emitted from the light source 2 is natural light having the property of circularly polarized light, and after passing through the relay optical system 3, enters the polarization beam splitter 4. The polarization beam splitter 4 is
The light from the light source 2 is separated by the dielectric multilayer film 4a into reflected linearly polarized light (S polarized light) and transmitted linearly polarized light (P polarized light).
The S-polarized light is further separated into three primary colors of red (R), green (G), and blue (B) by the cross dichroic mirror 5 and is incident on each spatial light modulator 6B, 6G, 6R. At this time, if the voltage is selectively supplied to each of the spatial light modulators 6B, 6G, and 6R according to the constituent pixels of the image to be projected, the S-polarized light is partially rotated in the polarization direction according to the image. The light becomes image light, which is re-incident on the cross dichroic mirror 5 and is combined to become combined image light, which is re-incident on the polarization beam splitter 4. In this case, the spatial light modulators 6B, 6
The S polarized light incident on G and 6R becomes S + P polarized light by being modulated by the video signal. Therefore, P of the combined image light re-incident on the polarization beam splitter 4 is
Only polarized light passes through the polarization beam splitter 4, passes through the projection optical system 7, and is enlarged and projected on a screen (not shown) to form a projected image.

The light source 2 is fixed in the housing 1 by a fixing member 8. Polarization beam splitter 4, cross dichroic mirror 5, spatial light modulators 6B, 6G, 6
The R and the like are fixed on the frame 9 after the optical axis adjustment and the position adjustment of each part.

When using such a liquid crystal projector, place the liquid crystal projector on a desk or a dedicated stand 10,
The left and right height adjusting mechanisms 11 provided on the front end side of the lower surface of the housing 1 are manually rotated to adjust the projection image position (projection angle) and the horizontal inclination of the projection image.

[0006]

As described above, in the conventional liquid crystal projector, two height adjusting mechanisms 11 are used to adjust the projection angle and the horizontal inclination of the projected image. However, since the height adjusting mechanisms 11 can only be adjusted one by one, adjusting one of the height adjusting mechanisms 11 causes the housing 1 to be tilted as shown in FIG. 5, and the screen 12 accordingly. The upper projection image 13 also tilts. Therefore, since it is necessary to operate the other height adjusting mechanism 11 to correct the inclination of the housing 1, there is a problem that adjustment takes time.

Recently, a so-called presentation has been actively conducted by connecting a liquid crystal projector and a personal computer. In this presentation, a document file, a graph, etc. are displayed as a format file of vertical writing paper, or a report paper or a business document is directly read by a scanner or the like and displayed by a liquid crystal projector.
However, since LCD projectors have a horizontally long screen due to the standards of conventional TV broadcasting and high-definition broadcasting, reducing the size to display a vertically long format file makes it difficult to see the contents of the important document or the projection screen. Most of it is wasted. In addition, since the up / down / left / right scroll operation needs to be frequently performed during the presentation when the image is not reduced, the user cannot concentrate on the original important presentation or the presentation is interrupted during scrolling. There were problems such as not being able to use time effectively.

The present invention has been made in order to solve the above-mentioned conventional problems, and it is an object of the present invention to adjust the inclination in the horizontal direction by using a height adjusting mechanism instead of the horizontal adjustment of the projection image. An object of the present invention is to provide a liquid crystal projector capable of automatically correcting the inclination of the direction. It is another object of the present invention to provide a liquid crystal projector capable of easily switching between a vertically long screen and a horizontally long screen.

[0009]

In order to achieve the above object, the present invention comprises a spatial light modulator for modulating light by a video signal, and the spatial light modulator is the optical axis of a projection optical system or the optical axis. A self-balancing mechanism is provided that is rotatably held about an arbitrary axis parallel to, and detects the inclination of the spatial light modulator in the horizontal direction by a sensor and automatically corrects it. Further, the present invention is a dichroic mirror that decomposes and combines the polarized waves split by the polarization beam splitter into red, green, and blue color lights, and a space that modulates each color light decomposed by the dichroic mirror by a video signal. An optical block is provided by integrating the spatial light modulator with the dichroic mirror, and the optical block is rotatable about the optical axis of the projection optical system or an arbitrary axis parallel to the optical axis. An automatic balancing mechanism is provided for holding the optical block and automatically correcting the horizontal inclination of the optical block by a sensor. Further, in the present invention, the automatic balancing mechanism is
An actuator for rotating the spatial light modulator about the optical axis of the projection optical system or an arbitrary axis parallel to the optical axis, and an image position controller for controlling the drive of the actuator by a signal from the sensor are provided. Characterize. Further, in the present invention, the automatic balancing mechanism, the actuator for rotating the optical block around the optical axis of the projection optical system or an arbitrary axis parallel to the optical axis, and drive control of this actuator by a signal from the sensor. An image position control unit is provided. Further, the present invention is characterized by including a portrait / landscape screen changeover switch. Further, in the present invention, the image position control unit is characterized by controlling the drive of the actuator by the signal from the portrait / landscape screen changeover switch and, at the same time, controlling the drive circuit of the spatial light modulator. Furthermore, the present invention is characterized in that means for outputting the signal state of the portrait / landscape screen changeover switch from the liquid crystal projector is provided.

In the present invention, the automatic balancing mechanism automatically corrects the inclination of the spatial light modulator or the optical block in the horizontal direction. In this correction, the sensor detects the inclination of the spatial light modulation element or the optical block, the image position control unit sends a signal to the actuator by the signal of this sensor, and the actuator detects the inclination of the spatial light modulation element or the optical block based on this signal. It is performed by rotating until the inclination becomes zero. Further, the image position control unit controls driving of the actuator and the spatial light modulator driving circuit simultaneously by a signal from the portrait screen / landscape screen switch.
At this time, the actuator rotates the optical block by 90 °, the drive circuit exchanges the scanning of the image signal of the spatial light modulator in the X direction and the Y direction, and the image is projected normally even if the screen is rotated by 90 °. To control. As a result, the portrait screen and the landscape screen are switched. The signal state of the portrait / landscape screen switch is output from the liquid crystal projector by means such as RS-232C, which is transmitted to the personal computer side. On the personal computer side, when the output from the projector is input,
It is possible to switch the conventional analog R, G, B signal output of a horizontally long screen to the output of analog R, G, B signals which can be easily displayed in a vertically long screen.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the embodiments shown in the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment in which the liquid crystal projector according to the present invention is applied to a monochrome liquid crystal projector. The constituent members and the like described in the section of the prior art are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. In the figure, the light source 2
And the projection optical system 7 are arranged so that the optical axes L1 thereof coincide with each other. The spatial light modulator 6 is arranged so that its center coincides with the optical axis L1. Further, the spatial light modulator 6 is held rotatably around the optical axis L1, and the horizontal tilt is automatically corrected by the automatic balancing mechanism 22.

FIG. 2 is a schematic configuration diagram showing an embodiment in which the liquid crystal projector according to the present invention is applied to a color liquid crystal projector. In the figure, the light source 2 and the relay optical system 3 are provided with an optical axis L1 above the polarization beam splitter 4.
Are arranged so as to be orthogonal to the optical axis L2 of the polarization beam splitter 4, the cross dichroic mirror 5, and the projection optical system 7. The cross dichroic mirror 5 and the spatial light modulators 6B, 6G, and 6R are housed in the case 20 and integrated to form an optical block 21. The optical block 21 is rotatably held around the optical axis L2 of the polarization beam splitter 4, the cross dichroic mirror 5 and the projection optical system 7, and the horizontal tilt is automatically corrected by the automatic balancing mechanism 22. It is supposed to be done.

Here, the automatic balancing mechanism 22 means the light source 2,
Even if the housing 1 for accommodating the spatial light modulator 6 and the like is tilted as shown in FIG. 4B, the optical block 21 is placed on the side opposite to the tilt direction of the housing 1 around the optical axis L2. Rotating the same angle as the tilt angle to automatically correct or correct the tilt, and level the image 13 projected on the screen 11.

More specifically, the automatic balancing mechanism 22
Detects the tilt of the optical block 21, corrects the tilt by rotating the optical block 21 by the same angle as the tilt angle in the opposite direction to the tilt direction, and projects it on the screen 12 as shown in FIG. This is a mechanism for leveling the image 13 to be displayed. The automatic balancing mechanism 22 includes a step motor 23 as an actuator for rotating the optical block 21 about the optical axis L2, and a level sensor 24 for sequentially detecting how much the optical block 21 is inclined with respect to the gravity direction. An image position control unit 25 for driving and controlling the step motor 23 by a signal 24a from the level sensor 24 is provided. The level sensor 24 is fixed to the case 20 and sends an output signal 24a having a magnitude corresponding to the inclination angle of the optical block 21 with respect to the gravity direction to the image position control section 25. Image position control unit 25
Sends a drive signal 25A to the drive circuit of the step motor 23 based on the output signal 24a. Therefore, the step motor 23 is driven to rotate the optical block 21 in the direction opposite to the tilt direction by the same angle as the tilt angle, and the tilt is automatically corrected. The automatic balancing mechanism 22 shown in FIG.
Also has the same configuration as the automatic balancing mechanism 22 shown in FIG. 2, but differs in that the spatial light modulator 6 itself is rotated.

In the liquid crystal projector having such a structure, the light source 2, the spatial light modulator 6, and the projection optical system 7 are provided.
Even if the housing 1 for accommodating the like is placed tilted to the left or right, the spatial light modulator 6 or the optical block 21 is rotated by the automatic balancing mechanism 22 to the side opposite to the tilted side of the housing. Since the inclination in the horizontal direction is automatically corrected, the projection image 13 is projected horizontally on the screen 11. Therefore, the operation for adjusting the inclination of the image is not necessary, and the adjustment operation is easy if only the projection angle is adjusted.

Further, in FIG. 2, the image position control unit 25 is connected to a portrait / landscape screen changeover switch 26 provided on the housing 1. When the signal 26a from the switch 26 is input, the image position control unit 25 drives and controls the step motor 23, and at the same time, the liquid crystal driver (driving circuit) 27 of the spatial light modulators 6B, 6G, 6R.
Control. That is, the image position control unit 25 is
The signal 26a from the horizontally long screen changeover switch 26 determines whether the user desires the vertically long screen or the horizontally long screen. For example, in the case of the horizontally long screen, the step based on the signal from the level sensor 24 as described above is performed. The motor 23 is drive-controlled to rotate the optical block 21 in a horizontal state. Further, the operation of the liquid crystal driver 27 will be briefly described by taking a TV signal scan as an example. As usual, the liquid crystal driver 27 uses a horizontal image signal of one line as a scan signal in the X direction.
Hereinafter, the 2-line and 3-line signals are sent to the liquid crystal driver 27 as the control signal 25B so as to supply the scanning signals to the spatial light modulators 6B, 6G and 6R in the Y direction. On the other hand, when the user operates the portrait / landscape screen change switch 26 to switch from the landscape screen to the portrait screen in a presentation or the like, the step motor 23 is drive-controlled based on a signal from the switch 26. At this time, the step motor 23 rotates the optical block 21 about the optical axis L2 in a predetermined direction by 90 ° to make it vertical. Further, at this time, the liquid crystal driver 27, contrary to the usual case, the horizontal image signal of one line is used as a scanning signal in the Y direction, and the following two lines are used.
The 3-line signals are transmitted in the X direction by the spatial light modulators 6B, 6G, 6
The control signal 25B is sent to the liquid crystal driver 27 so that the scanning signal is supplied to R. As a result, the projection screen is switched to the portrait screen.

In the liquid crystal projector having such a structure, even if the projector itself is mounted tilted to the right (or left) as shown in FIG. 5, the automatic balancing mechanism 22 causes the optical block 21 to be mounted on the projector. Since the tilt in the horizontal direction is automatically corrected by rotating it to the side opposite to the tilt side, it is not necessary to adjust the tilt of the housing 1 by the height adjusting mechanism 11, and the projected image 13 as shown in FIG. Can be projected on the screen 12 without tilting.

Further, since the conventional projector has a horizontally long screen, when a vertically long format file is displayed at one time, it is necessary to reduce the size of the projected image, or to scroll up, down, left and right when not reducing the size. However, in the present invention, since the horizontally long screen can be switched to the vertically long screen for projection by rotating the optical block 21 by 90 °, the operation is easy without the need. In addition, the content of the document is easy to see because it does not need to be reduced.

Further, in the conventional hanging type liquid crystal projector in which the projector is installed upside down for the purpose of installing the housing 1 on the ceiling and the like, it is usually necessary to invert the screen vertically and horizontally by manual operation. In the present invention, since the level sensor 24 can detect this, the image position control unit 25 operates the step motor 23 to operate the optical block 2.
A balanced projection image can be realized simply by rotating 1 by 180 °.

The present invention is not limited to the above-described embodiment, and various modifications and changes can be made. For example, the polarization beam splitter 4 and the optical block 2 can be used.
1 may be integrally provided, or instead of using the step motor 23, a DC motor, an ultrasonic motor or the like may be used as an actuator. Further, the spatial light modulator or the optical block may be held rotatably around an arbitrary axis parallel to the optical axis of the projection optical system. In addition, the image position control unit 25
Can be realized by an inexpensive MPU (microprocessor unit) and motor driver. Further, the conversion of the video signal into the horizontally long screen and the vertically long screen can also be performed by a method of expanding the image signal on a VRAM (Video Random Access Memory) and performing address conversion by 90 ° rotation in the vertical and horizontal directions. Further, when the signal state of the portrait / landscape screen changeover switch 26 is transmitted to the personal computer side by the output means such as RS-232C from the liquid crystal projector, the personal computer side displays the analog R of the conventional landscape screen,
Analog clock R, which makes it easy to display G and B signal outputs in portrait orientation
The output can be switched to G and B signals, and the application range can be expanded.

[0021]

As described above, the liquid crystal projector according to the present invention is provided with the spatial light modulation element that modulates light by the image signal, and the spatial light modulation element is parallel to the optical axis of the projection optical system or the optical axis. Since an automatic balance mechanism is provided that is rotatably held around an arbitrary axis and detects the horizontal tilt of the spatial light modulator by a sensor and automatically corrects it, the projector itself can be mounted tilted. However, the attitude of the spatial light modulator can be automatically corrected by the automatic balancing mechanism. Therefore, it is possible to eliminate the inconvenience of simultaneously adjusting the position of the projected image and adjusting the tilt while observing the image projected on the screen, and the operation for adjustment during placement is easy and quick setup is possible. .

Further, according to the present invention, a dichroic mirror for decomposing and synthesizing the polarized waves split by the polarization beam splitter into red, green, and blue color lights, and each color light decomposed by the dichroic mirror by a video signal. A spatial light modulation element for modulating is provided, and the spatial light modulation element and the dichroic mirror are integrated into an optical block, and this optical block is rotatably held around the optical axis of the projection optical system. Since an automatic balancing mechanism that detects the inclination of the direction and automatically corrects it,
The same effects as those of the above-described invention can be obtained.

Further, according to the present invention, the image position control unit is vertically long /
Since the actuator is driven and controlled by the signal from the landscape screen change switch to rotate the optical block and the drive circuit of the spatial light modulator is controlled at the same time, it is necessary to project in a portrait screen when using it in a presentation. As a result, an efficient and effective presentation can be performed without the need for complicated scrolling operations and reduced projection on the landscape screen. Further, the present invention provides
Since the means for outputting the signal state of the portrait / landscape screen changeover switch from the liquid crystal projector is provided, when the output is input to the personal computer, the conventional analog R, G, B signal output of the landscape screen is displayed vertically. It is possible to switch to the output of analog R, G, B signals which can be easily displayed by.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment in which a liquid crystal projector according to the present invention is applied to a monochrome liquid crystal projector.

FIG. 2 is a schematic configuration diagram showing an embodiment in which the liquid crystal projector according to the present invention is applied to a color liquid crystal projector.

3A and 3B are diagrams showing an image on a screen and a state of a housing in the present invention.

FIG. 4 is a schematic configuration diagram showing a conventional example of a liquid crystal projector.

FIG. 5 is a diagram showing an image on a screen and a state of a housing in a conventional device.

[Explanation of symbols]

1 ... Housing, 2 ... Light source, 3 ... Relay optical system, 4 ... Polarization beam splitter, 5 ... Cross dichroic mirror,
6, 6B, 6G, 6R ... Spatial light modulation element, 7 ... Projection optical system, 20 ... Case, 21 ... Optical block, 22 ... Automatic balancing mechanism, 23 ... Step motor, 24 ... Level sensor,
25 ... Image position control unit, 26 ... Vertical / horizontal screen switching switch, 27 ... Liquid crystal driver, L1, L2 ... Optical axis.

Claims (7)

[Claims] 1. A spatial light modulation element for modulating light according to a video signal, the spatial light modulation element being held rotatably around an optical axis of a projection optical system or an arbitrary axis parallel to the optical axis. A liquid crystal projector comprising an automatic balancing mechanism for detecting a horizontal inclination of the spatial light modulator by a sensor and automatically correcting the inclination. 2. A dichroic mirror that decomposes and combines the polarized waves split by the polarization beam splitter into red, green, and blue color lights, and spatial light that modulates each color light decomposed by the dichroic mirror by a video signal. A spatial light modulator and a dichroic mirror are integrated to form an optical block, and the optical block is held rotatably around the optical axis of the projection optical system or an arbitrary axis parallel to the optical axis. Then, the liquid crystal projector is provided with an automatic balancing mechanism for automatically correcting the horizontal inclination of the optical block by a sensor. 3. The liquid crystal projector according to claim 1, wherein the automatic balancing mechanism rotates the spatial light modulator about an optical axis of the projection optical system or an arbitrary axis parallel to the optical axis, and an actuator. A liquid crystal projector comprising an image position control section for driving and controlling an actuator according to a signal from a sensor. 4. The liquid crystal projector according to claim 2, wherein the automatic balancing mechanism rotates the optical block around the optical axis of the projection optical system or an arbitrary axis parallel to the optical axis, and the actuator. A liquid crystal projector comprising an image position control unit that controls driving by a signal from a sensor. 5. The liquid crystal projector according to claim 1, 2, 3 or 4, further comprising a portrait / landscape screen changeover switch. 6. The liquid crystal projector according to claim 5, wherein the image position control unit drives and controls the actuator by a signal from the portrait / landscape screen changeover switch, and at the same time.
A liquid crystal projector characterized by controlling a drive circuit of a spatial light modulator. 7. The liquid crystal projector according to claim 5, further comprising means for outputting the signal state of the portrait / landscape screen changeover switch from the liquid crystal projector.