JPH09197249A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically adjust focus, a field angle, or a swing and tilt. SOLUTION: The lights modulated by liquid crystal panels 3R, 3G, and 3B are put together by an optical part 2 and projected on a screen through a focus lens 7 and a zoom lens 9. The light reflected by the screen as a range-finding image pattern light is projected passes through a slit 12 and is made incident on a line sensor 13. An MPU 14 finds the distance to the screen from the position of the reflected light on the line sensor 13. Then a focus actuator 8 is controlled according to the found distance to move the focus lens 7 so that the image on the screen is put in focus.

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 projector having a focus adjusting function, an angle of view adjusting function or a tilt adjusting function.

[0002]

2. Description of the Related Art Focus adjustment in a conventional projection type liquid crystal projector has been performed by a user operating a projection lens while watching an image on a screen. Similarly, the angle of view adjustment for projecting an appropriate size on the screen is also performed manually. Further, when the screen is not perpendicular to the optical axis of the projection lens but is tilted, even if focus adjustment is performed, only a part of the screen is in focus, so it is difficult to focus on the entire screen. In such a case, it is necessary to tilt the projector itself according to the screen.

Also, by measuring the distance to the screen,
A liquid crystal projector that adjusts the focus based on this distance has been proposed (JP-A-3-257443 and JP-A-4).
-10785). These are the same as the infrared active method that is frequently used in AF systems such as lens shutter cameras that use infrared rays for distance measurement.

[0004]

As described above, in the conventional liquid crystal projector, the user manually performs the focus adjustment, the angle of view adjustment, or the tilt adjustment for correcting the tilt of the screen. There was a problem that a complicated adjustment had to be made every time the installation location was changed or the screen was changed. Further, in the methods disclosed in JP-A-3-257443 and JP-A-4-10785, since infrared rays are used, they are invisible to the human eye and the distance is measured at any position on the screen. However, there is a problem that it is not possible to confirm whether the focus is on or not and at which position the focus is adjusted. The present invention has been made in order to solve the above problems, and a liquid crystal projector capable of visually confirming a measurement point at the time of measuring a distance and the like and automatically performing focus adjustment, angle of view adjustment, or tilt adjustment. The purpose is to provide.

[0005]

According to a first aspect of the present invention, there is provided a liquid crystal panel comprising a liquid crystal panel for modulating light from a light source according to an input video signal and a focus lens for focus adjustment. From the screen, the projection unit that projects the light modulated by the screen to the screen, the focus actuator that drives the focus lens, the image pattern signal generation unit that gives the LCD panel a video signal for displaying the adjustment image pattern on the screen, The slit arranged so that the reflected light of the light enters, the light receiving part that senses the light that has passed through this slit, and the distance to the screen is calculated from the position of the light on this light receiving part. And a control unit for controlling and moving the focus lens. In this way, by applying the video signal to the liquid crystal panel from the image pattern signal generating section, the adjustment image pattern is projected on the screen, and the reflected light thereof passes through the slit and is incident on the light receiving section. The control unit measures the distance to the screen using the principle of so-called triangulation, which determines the distance depending on where on the light receiving unit the reflected light is observed, and moves the focus lens.

Further, as described in claim 2, a liquid crystal panel, a projection unit having a zoom lens for adjusting an angle of view, a zoom actuator for driving the zoom lens,
The distance to the screen is obtained from the image pattern signal generator, the slit, the light receiver, and the light position on the light receiver, and the image pattern is moved on the screen to determine the size of the screen according to the light position on the light receiver. And a control unit for controlling the zoom actuator and moving the zoom lens based on the calculated distance and the size of the screen. In this way, the control unit moves the adjustment image pattern on the screen to obtain the size of the screen from the position of the light on the light receiving unit, and moves the zoom lens based on the obtained distance and the size of the screen.

Further, as described in claim 3, the liquid crystal panel, the projection unit, the tilt actuator for driving the projection unit, the image pattern signal generating unit, the slit, the light receiving unit, and the light receiving unit. The distance to the screen is calculated from the position of the light, the image pattern is moved on the screen, the tilt of the screen is calculated from the position of the light on the light receiving part, and the tilt actuator is controlled based on the calculated distance and the tilt of the screen. And a control unit that tilts the projection unit back and forth. Thus, the control unit moves the adjustment image pattern on the screen to obtain the screen tilt from the position of the light on the light receiving unit, and tilts the projection unit back and forth based on the distance and the screen tilt. Moreover, as described in claim 4, the slit is provided with a polarization filter.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

1. Embodiment 1. FIG. 1 is a block diagram of a projection type liquid crystal projector showing a first embodiment of the present invention. 1 is the body of the liquid crystal projector, 2 is the three components of the light source (red,
Optical sections 3R, 3G, and 3B for separating and synthesizing into green and blue) are liquid crystal panels for modulating the separated color lights by image signals, 4 is a liquid crystal drive circuit for driving each liquid crystal panel, 5
Is a liquid crystal driver control unit for selecting a video signal from a pattern ROM or a video signal input unit, which will be described later, and giving it to the liquid crystal drive circuit 4. Reference numeral 6 is a liquid crystal driver control unit 5 for outputting a video signal for displaying an adjustment image pattern on the screen. 2 is a pattern ROM that serves as an image pattern signal generation unit to be given to

Further, 7 is a focus lens for focus adjustment, 8 is a focus actuator for driving the focus lens 7, 9 is a zoom lens for adjusting the angle of view, and 1 is a zoom lens.
0 is a zoom actuator for driving the zoom lens 9,
Reference numeral 12 is a slit, 13 is a line sensor that serves as a light-receiving unit that senses light that has passed through the slit 12, 14 is an MPU that serves as a control unit that controls the liquid crystal projector, and 15 is an MPU 14.
Is a screen ROM that stores information for calculating the distance to the screen or the size of the screen,
Reference numeral 16 is a video signal input unit for inputting a video signal given from the outside to the liquid crystal projector.

The projection unit for projecting the light modulated by the liquid crystal panels 3R, 3G, 3B on the screen is composed of a plurality of lenses (not shown) including the focus lens 7 and the zoom lens 9. Next, the operation of such a liquid crystal projector will be described. The optical section 2 has the structure shown in FIGS. 2 and 3 of the above-mentioned Japanese Patent Laid-Open No. 3-257443, for example. Then, the light source light incident on the inside of the optical unit 2 from a light source (not shown) is converted into R by the optical unit 2.
It is separated into (red), G (green), and B (blue) color lights and projected on the liquid crystal panels 3R, 3G, and 3B, respectively.

The respective reflected lights from the liquid crystal panels 3R, 3G, 3B are combined by the optical section 2 and emitted in the direction of the focus lens 7. Thus, the liquid crystal panels 3R, 3
The light modulated by G and 3B passes through the focus lens 7 and the zoom lens 9 and is projected on a screen (not shown). Since the liquid crystal panels 3R, 3G, and 3B have a property of rotating incident light according to a video signal, when the incident light is S-polarized light, its reflected light, that is, light emitted from the liquid crystal projector is P-polarized light. Become light.

FIG. 2 is a diagram for explaining a focus adjusting operation in such a liquid crystal projector. However, in FIG. 2, a part of the configuration of the liquid crystal projector of FIG. 1 is omitted. The liquid crystal driver control section 5 selects the video signal output from the pattern ROM 6 under the control of the MPU 14, and the liquid crystal drive circuit 4 converts this video signal into a liquid crystal drive signal and applies it to the liquid crystal panels 3R, 3G, 3B. This allows
An image pattern for distance measurement is projected on the center of the screen 17.

At this time, as the image pattern for distance measurement,
The circular spot image pattern 21 shown in FIG. 3A may be used, or the vertical line image pattern 22 shown in FIG.
May be. The pattern 21 has an advantage that the distance can be accurately measured even when the screen 17 is tilted, and the pattern 22, which is longer in the vertical direction than the pattern 21, has an advantage that it is easier to detect reflected light than the pattern 21. There is.

The light reflected by the screen 17 by the projection of the image pattern light passes through the slit 12 and enters the line sensor 13 in which pixels are arranged in the horizontal direction. At this time, when the screen 17 is at the position A in FIG. 2, the reflected light from the screen 17 is reflected by the line sensor 13.
Observed at point a above. Also, the screen 17 is at position B
In the case of, the reflected light is observed at point b on the line sensor 13. In this way, the liquid crystal projector and screen 1
When the distance X from 7 is different, the position on the line sensor 13 where the reflected light is observed is different.

In the screen ROM 15, the correspondence between the position on the line sensor 13 and the distance X is registered in advance, and the MPU 14 determines the corresponding distance X based on the position of the reflected light observed on the sensor 13. Screen ROM 15
Read from In this way, the distance X between the liquid crystal projector and the screen 17 can be measured easily and quickly. Subsequently, the MPU 14 controls the focus actuator 8 based on the obtained distance X to cause the screen 1
Focus lens 7 so that the image on 7 is in focus.
To move. This completes the focus adjustment.

FIG. 4 is a diagram for explaining the angle-of-view adjustment operation in the liquid crystal projector of this embodiment. MPU
After finishing the measurement of the distance X, the screen 14 displays the image pattern stored in the pattern ROM 6 in the same manner as described above on the screen 17
To project. The image pattern at this time is as shown in FIG.
The vertical line image pattern 22 shown in (b) is suitable.

Then, the MPU 14 instructs the liquid crystal driver control section 5 to move the image pattern to the right of the screen 17 (downward in FIG. 4). As a result, when the image pattern moves to the right on the screen 17,
The position of the reflected light observed by the line sensor 13 moves leftward from the position a observed during the distance measurement, and eventually the reflected light cannot be observed at the position a1 on the sensor 13.

Subsequently, the MPU 14 instructs the liquid crystal driver controller 5 to move the image pattern to the left of the screen 17 (upward in FIG. 3). As a result, the position of the reflected light observed by the line sensor 13 moves to the right, and eventually the reflected light cannot be observed at the position a2 on the sensor 13. Next, the MPU 14 performs the distance X1 from the positions a1 and a2 on the line sensor 13 to the right end of the screen 17 and the distance X to the left end similarly to the measurement of the distance X.
2 is calculated, and the horizontal angle of view θ is calculated using these X1 and X2 and the distance X to the center of the screen 17.

A correspondence relationship between the distance X and the angle of view θ and the vertical and horizontal sizes of a commercially available screen is registered in the screen ROM 15 in advance, and the MPU 14 stores the corresponding screen based on the obtained distance X and the angle of view θ. The size is read from the screen ROM 15. Thus, the screen 17
The size of can be determined easily and quickly. Then, the MPU 14 controls the zoom actuator 10 based on the obtained distance X and the size of the screen 17 in the lateral direction, and moves the zoom lens 9 so that the screen 17 can be projected at an optimum angle of view. This completes the angle of view adjustment.

Embodiment 2 FIG. 5 is a block diagram of a liquid crystal projector showing another embodiment of the present invention. The same components as those in FIG. 1 are designated by the same reference numerals. Reference numeral 6a is an image pattern signal generating section for generating an image pattern similar to that of the pattern ROM 6 and for generating an adjustment image pattern for obtaining the screen inclination.
OM and 10a are tilt actuators that drive the projection unit including the focus lens 7 and the zoom lens 9.

Reference numeral 13a designates a line sensor which serves as a light receiving portion capable of selecting a pixel arrangement direction by a rotation mechanism (not shown), and 14a, like the MPU 14, obtains the distance to the screen and the size of the screen, and at the same time MP that becomes a control unit that performs tilt adjustment by obtaining the tilt
U and 15a store the same information as the screen ROM 15 of FIG. 1, and a screen RO that stores information for the MPU 14a to calculate the screen tilt.
M.

First, the MPU 14a is the MPU 14 of FIG.
Similarly, the distance to the screen 17 is measured, and then the size of the screen 17 is obtained. At this time, the line sensor 13a is a horizontal line sensor as in the first embodiment. Next, the MPU 14a rotates the line sensor 13a by 90 ° so that the pixel becomes a vertical line sensor in which pixels are arranged in the vertical direction. Then, as in the case of the first embodiment, the image pattern stored in the pattern ROM 6a is projected on the screen 17. As the image pattern at this time, the horizontal line image pattern 23 shown in FIG. 3C is suitable.

Then, the MPU 14a instructs the liquid crystal driver control section 5 to move the image pattern downward in the screen 17. As a result, when the image pattern moves downward on the screen 17, the sensor 13a
The position of the reflected light observed at
The reflected light cannot be observed at the position c1 on 3a. Then, the MPU 14a instructs the liquid crystal driver control unit 5 to move the image pattern in the upward direction of the screen 17. As a result, the position of the reflected light observed by the line sensor 13a moves downward, and the position c2 on the sensor 13a moves.
The reflected light can no longer be observed at.

Here, the positions c1 and c2 on the sensor 13a
Depends on the distance X to the screen 17, the vertical size of the screen 17, and the inclination α of the screen 17. The screen ROM 15a includes a line sensor 13a.
The correspondence between the upper position, the distance X, the vertical size of the screen 17, and the inclination α is registered in advance.

The MPU 14a sets the corresponding inclination α to the screen ROM 15a based on the distance X obtained in the same manner as in the first embodiment, the vertical size of the screen 17 and the position of the reflected light observed on the sensor 13a. Read from. In this way, the inclination α of the screen 17 can be obtained. Then, the MPU 14a controls the swing actuator 10a based on the obtained distance X and the inclination α,
The optical lens group such as the focus lens 7 and the zoom lens 9 is tilted back and forth so that an image similar to that of the screen perpendicular to the optical axis is projected with respect to the screen 17 inclined by α from the surface perpendicular to the optical axis of the projection lens system. .

At this time, the inclination of the lens is determined based on Scheimpflug's law. That is, as shown in FIG. 6, the lenses 7 and 9 are inclined so that the extension line of the lens intersects the intersection P between the extension line of the screen 17 and the extension line of the optical unit 2. Therefore, in the state shown in FIGS. 5 and 6 in which the upper portion of the screen 17 is tilted toward the liquid crystal projector side, the lenses 7 and 9 are tilted so as to face obliquely above the projector (tilt up). Screen 1
When the upper part of 7 is tilted to the opposite side, lenses 7, 9
Is tilted so that it faces diagonally below the projector (tilt down).

Thus, the tilt adjustment is completed. In addition,
Which lens in the optical lens group is tilted depends on how the optical system is designed, and it is not always necessary to move all the lenses.

Further, in the first and second embodiments, the light emitted from the liquid crystal projector and reflected by the screen 17 is P-polarized light. Therefore, if a polarizing filter that allows the P-polarized light to pass is arranged in the slit 12, disturbance will occur. It is possible to prevent false measurement due to light. Further, in the first and second embodiments, the line sensor is used as the light receiving unit, but an inexpensive sensor such as a silicon photodiode may be moved to observe the position of the reflected light. Needless to say, an area sensor may be used for the light receiving section.

[0029]

According to the present invention, since the control unit moves the focus lens by obtaining the distance to the screen based on the position on the light receiving unit where the reflected light of the adjustment image pattern is observed, the optimum focus is obtained. Adjustments can be made automatically. In addition, since the distance is measured with the adjustment image pattern that uses the same visible light as in normal video, you can easily check where on the screen you are measuring, and the means for generating infrared light and visible light and infrared Focus adjustment can be realized without increasing a special mechanism such as separating light.

Further, since the control section moves the adjustment image pattern on the screen to obtain the size of the screen from the position of the light on the light receiving section and moves the zoom lens,
It is possible to automatically adjust the angle of view for projecting an appropriate size on the screen. Further, since the control unit moves the adjustment image pattern on the screen to obtain the screen tilt from the position of the light on the light receiving unit and tilts the projection unit back and forth, the tilt adjustment for the screen tilt can be automatically performed. You can Further, by providing the polarization filter in the slit, it is possible to receive only the polarized light from the liquid crystal projector, so that it is possible to prevent erroneous measurement due to ambient light.

[Brief description of drawings]

FIG. 1 is a block diagram of a liquid crystal projector showing a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a focus adjustment operation in the liquid crystal projector of FIG.

FIG. 3 is a diagram showing an example of an adjustment image pattern.

FIG. 4 is a diagram for explaining an angle-of-view adjustment operation in the liquid crystal projector of FIG.

FIG. 5 is a block diagram of a liquid crystal projector showing another embodiment of the present invention.

6 is a diagram for explaining the principle of tilt adjustment in the liquid crystal projector of FIG.

[Explanation of symbols]

2 ... Optical unit, 3R, 3G, 3B ... Liquid crystal panel, 4 ... Liquid crystal drive circuit, 5 ... Liquid crystal driver control unit, 6 and 6a ... Pattern ROM, 7 ... Focus lens, 8 ... Focus actuator, 9 ... Zoom lens, 10 ... Zoom actuator, 10a ... Tilt actuator, 12 ... Slit, 13,13a ... Line sensor, 14,14a ...
MPU, 15, 15a ... Screen ROM.

Claims (4)

[Claims] 1. A liquid crystal panel that modulates light from a light source according to an input video signal, a projection unit that includes a focus lens for focus adjustment, and that projects the light modulated by the liquid crystal panel onto a screen, the focus. A focus actuator that drives the lens, an image pattern signal generator that gives a video signal for displaying an adjustment image pattern on the screen to the liquid crystal panel, and a slit arranged so that reflected light from the screen enters. It has a light receiving part for sensing the light passing through this slit, and a control part for obtaining the distance to the screen from the position of the light on this light receiving part and controlling the focus actuator based on this result to move the focus lens. LCD projector characterized by. 2. A liquid crystal panel that modulates a light source light according to an input video signal, and a projection unit that includes a zoom lens for adjusting an angle of view, and that projects the light modulated by the liquid crystal panel onto a screen. A zoom actuator that drives the zoom lens, an image pattern signal generator that gives a video signal for displaying an adjustment image pattern on the screen to the liquid crystal panel, and a slit arranged so that the reflected light from the screen is incident. , The light receiving part that senses the light passing through this slit and the position of the light on this light receiving part are used to determine the distance to the screen, and the image pattern is moved on the screen to determine the size of the screen by the light position on the light receiving part. Seeking
A liquid crystal projector, comprising: a control unit that controls a zoom actuator to move a zoom lens based on the obtained distance and screen size. 3. A liquid crystal panel that modulates light from a light source according to an input video signal, a projection unit that projects the light modulated by the liquid crystal panel onto a screen, a tilt actuator that drives the projection unit, and a tilt actuator on the screen. An image pattern signal generator that gives an image signal for displaying the adjustment image pattern to the liquid crystal panel, a slit arranged so that reflected light from the screen is incident, and a light receiver that senses light passing through this slit. Then, the distance to the screen is obtained from the position of the light on the light receiving part, the image pattern is moved on the screen to obtain the screen tilt from the position of the light on the light receiving part, and based on the obtained distance and the screen tilt. , A liquid crystal projector having a control unit for controlling the tilt actuator to tilt the projection unit back and forth. 4. The liquid crystal projector according to claim 1, 2 or 3, wherein the slit includes a polarization filter.