JPH09270978A - Projection-type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically adjust a zoom lens, so that inputted signals having different ranges are projected to the whole range of a screen and to realize projection by means of effectively using the screen, without previously preparing numeric data for adjustment by detecting the end part of a projected video and adjusting the zoom lens so that the video is projected to the end part of the screen. SOLUTION: The device is provided with a video device main body 15 to which the zoom lens 16 is attached, the screen 10 and photodetectors 11, 12, 13 and 14 provided at the periphery of the effective range of the screen 10. The detection results of the photodetectors are transmitted to the main body 15 by a cable or radio, such as infrared light and a radio wave, a zoom lens mechanism for projection is controlled and desirable projection by using the end part of the screen 10 is realized. One or plural photodetectors are used, in response to purposes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device which always projects an image up to the end of the projection range of a screen for a plurality of different types of image input signals.

[0002]

2. Description of the Related Art A display device is used as a multi-sync type display device that automatically synchronizes and displays images in accordance with a plurality of video signals having different synchronization frequencies. Among them, in a device of the type that magnifies and projects by a lens using a dot type display unit such as a liquid crystal panel, if the number of dots of the image of the input signal and the number of dots of the display device do not match, the surroundings of the projected image are displayed. A blank portion occurs, the target image itself becomes small, and the projection screen is wasted.

As a means for solving this, there is a conventional adjusting method using a zoom lens. This is because the signal image with a dot number that does not match, that is, with a small number of dots, is adjusted to the same range as the signal image that displays all the dots of the display device by adjusting the zoom lens. The projection image is enlarged, and an example thereof is described in JP-A-6-337651. In the screen range adjustment function described in this publication, control signal information for driving the zoom lens position to a predetermined optimum value corresponding to each video signal is provided in the projection device system. A method is used in which the number of methods is held and the signals are extracted and used according to the type of input signal.

[0004]

The first problem of the prior art described in the above-mentioned publication is that the control signal information for adjusting the zoom lens position must be prepared in advance for the corresponding signal. There is. The reason is,
This is because there is no feedback function from the projection screen to the zoom lens control circuit, so that the position is adjusted to a position specified in advance by the control signal information.

The second problem is that it cannot cope with the case where the screen is small due to the black portion included in the signal. The reason is that in the adjustment using the control signal information prepared in advance, the entire screen is displayed regardless of the screen content, and thus the black portion is also displayed as a signal.

An object of the present invention is to provide a projection capable of automatically adjusting the zoom lens so as to project the input signals having different image ranges to the full range of the screen without preparing numerical data for adjustment in advance. Type display device.

Another object of the present invention is to provide a projection type display device capable of projecting an image on the entire screen by trimming an image input having a ratio different from the original aspect ratio of the device. .

[0008]

According to the present invention, the end portion of the actual projected image is detected, and the zoom lens is adjusted so as to project the image to the end portion of the screen.

More specifically, means for electrically storing and holding a video signal for a certain period of time in order to cope with fluctuations in the video signal, a switching device for switching between the stored video and the normal video, and a screen for detecting the video. It has a photodetector for arranging the four circles and an adjustment control circuit for driving the zoom lens until an image is detected.

According to the present invention, the adjustment operation is started and the input video signal is accumulated and held by switching the type of the input signal or by the operation of the user at an arbitrary time point, and after a certain time has elapsed, the accumulated signal is projected. To do. The zoom lens is driven and adjusted until the photodetector determines that the projected image has reached the end of the screen.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an example of device installation according to an embodiment of the present invention. In the figure, a video device main body 15 having a zoom lens 16 attached thereto, a screen 10 and a photodetector 1 provided around the effective range of the screen 10.
1, 12, 13, and 14, and sends the detection result of the photodetector to the main body 15 by a wired or wireless signal such as infrared rays or radio waves for zoom control. However, one or more photodetectors are used depending on the purpose.

Next, FIG. 2 shows a circuit configuration diagram for adjustment. First, the video input signal enters the signal synchronization determination circuit 201, performs synchronization determination, and outputs synchronization signal information to the switching circuit 203.
To the video display panel drive circuit 205 to drive the video display panel 208. In the present embodiment, the adjustment is started when the input signal is switched or the operator arbitrarily gives an instruction. Here, the peak of the video signal is held by the peak video signal holding circuit 202 for a predetermined time and used as a video signal for adjustment. This is switched from the normal input signal by the switching circuit 203 and sent to the video display panel drive circuit 205. Video display panel 2
The image displayed on 08 is projected on the projection screen 210 (corresponding to the screen 10 in FIG. 1) via the zoom lens mechanism 209. Then, the photodetector 211 provided around the projection screen 210 (the photodetectors 11 to 14 in FIG.
(Corresponding to one or more of the above) is operated, and the information of detection / non-detection thereof is sent to the adjustment control circuit 204 as a detection signal and the motor drive circuit 206 is controlled to drive the zoom lens mechanism 209.

FIG. 3 shows a flow of adjustment in the present invention. In the figure, there are two types of start of the adjusting function: when the input signal is switched and when an arbitrary operation is performed. At the time of signal switching, signal synchronization determination 302 is performed after signal switching 301, synchronization frequency switching 303 is performed, and adjustment is started after the image display panel is in a state in which it operates normally.

After the adjustment is started, the peak hold 304 of the input video signal is performed. This is repeated until the time determination 305 recognizes that the predetermined time has elapsed. When the peak hold ends after a lapse of a predetermined time, the video signal is switched and the peak signal projection 306 is performed. Next, the light detection is started 307. The flow is divided according to the presence / absence of detection in the detection determination 308. However, when a plurality of photodetectors are used, the result of the logical sum or logical product of the detection signals is used as the presence or absence of detection, depending on the purpose.

First, when the detection is first recognized, it is judged whether the zoom lens mechanism can perform the reduction operation 309.
If possible, zoom reduction 311 for one step is performed.
If the zoom lens mechanism cannot reduce at the end of the adjustment range, the zoom adjustment is finished and an indication of the limit of the adjustment 31
After performing step 7, the photodetector is stopped 315. After the one-step reduction 311, light detection 313 is performed again, and if there is still detection, the process returns to the reduction possibility determination 309. On the contrary, if the detection is lost, the light detection is stopped 315.

If no detection is found in the first detection judgment 308, the image is considered to be small, and the enlargement judgment 31
Go to 0. Here, it is determined whether or not the zoom lens mechanism can be operated in the enlargement direction, and if possible, one stage of zoom enlargement 312 is performed. On the contrary, when it is determined that the magnifying zoom cannot be performed, the display 317 indicating that the adjustment is at the limit is performed and the light detection is stopped 315. After the zoom enlargement 312, the light detection 314 is performed again, and if detected, the zoom enlargement is considered to have exceeded the range of the screen, and the one-step reduction operation 3
After inserting 18 and returning to the range, the light detection is stopped 315. When the detection is not recognized by the light detection 314 after zoom expansion, it is considered that the image has not reached the maximum range of the screen yet, and the process returns to the expansion possible determination 310. After the zoom adjustment is completed and the light detection is stopped 315 in this way, the video signal is switched and the normal signal is projected 316.

In the present invention, when the adjustment is started, only the specific one of the plurality of photodetectors is designated to be effective, so that the aspect ratios of the image display panel and the input image signal do not match. In this case, trimming processing can be performed. For example, when an image with an aspect ratio that is wider than that of the image display panel is input, the image is normally detected first in the horizontal direction, so there is a blank area in the vertical direction, but only the photodetectors in the vertical direction of the screen are effective. If this is done, the image in the horizontal direction will be outside the screen, but it can be projected onto the entire screen including the vertical direction.

[0018]

The first effect of the present invention is that the maximum projected image can be automatically obtained on the screen without limiting the input signal. The reason is that the actual video signal is detected and fed back to the display device for adjustment.

The second effect is that when a video signal having a ratio different from the original aspect ratio of the video device is output, the video can be projected on the entire screen by trimming. The reason is that there is a black portion in the video signal because the zoom lens mechanism is adjusted while detecting the actually projected video, rather than determining the type of the input signal and projecting it to a size corresponding to it. This is because, in this case, it can be determined as no signal without considering it as a part of the signal.

[Brief description of drawings]

FIG. 1 shows an apparatus arrangement according to an embodiment of the present invention.

FIG. 2 shows a circuit configuration of an embodiment of the present invention.

FIG. 3 shows a flow of adjustment of the present invention.

[Explanation of symbols]

10 screen 11, 12, 13, 14 photodetector 15 display device main body 16 zoom lens mechanism portion 201 signal synchronization determination circuit 202 peak video signal holding circuit 203 switching circuit 204 adjustment control circuit 205 video display panel drive circuit 206 motor drive circuit 207 Projection lamp 208 Image display panel 209 Zoom lens mechanism 210 Projection screen 211 Photodetector 301 Signal switching 302 Signal discrimination 303 Video panel driver sync frequency switching 304 Video signal peak hold 305 Peak hold time count 306 From normal signal to peak signal 307 Start of operation of photodetector 308 Branch depending on presence / absence of detection at start of adjustment 309 Judgment of driving of zoom lens in image reduction direction 310 Image enlargement of zoom lens Judgment of drive in the large direction 311 Zoom lens, 1-step reduction operation 312 Zoom lens, 1-step enlargement operation 313, 314 Detection by photo detector 315 Stop operation of photo detector 316 Switching from peak signal to normal signal 317 Indication that the adjustment range of the zoom lens mechanism is at the limit 318 Correction operation when the effective projection range is exceeded due to zoom enlargement at the adjustment stage

Claims (5)

[Claims] 1. A projection type display device, characterized in that a projection image range is changed by projecting a video signal and varying the enlargement ratio of a zoom lens mechanism in accordance with a signal detecting the projected video light. . 2. A plurality of photodetectors are provided as means for detecting the projected image light, and the magnification of the zoom lens mechanism is varied by selectively using the outputs of the plurality of photodetectors. Projection display device. 3. A plurality of photodetectors are provided as means for detecting the projected image light, and logically OR or AND processing is performed on the detection signals from the plurality of effective photodetectors in any combination. The projection display apparatus according to claim 1, wherein the magnification of the zoom lens is changed according to the processing result. 4. The projection display apparatus according to claim 1, wherein the input video signal is peak-held for a predetermined time, and the projected video range is changed using the peak-held video signal. 5. The projection display device according to claim 2, wherein a plurality of photodetectors are arranged at the end of the screen.