JPH10319506A - Focusing device for projection television - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a quick and accurate just focusing action regardlessly of the picture size of a projection video and without causing the individual difference of an adjustment person by providing a device with a deviation detection means comparing a signal with the reference signal of the forming means of a pattern for adjustment and detecting deviation and controlling a projection lens means based on a deviation signal obtained by the deviation detection means. SOLUTION: An image pickup video signal generated by an image pickup signal processing part 61 is inputted to a phase detection part 13 from a screen 57. The scanning line of a horizontal bar is counted with the vertical synchronizing signal of the image pickup video signal by the detection part 13 as a reference. Then, the values of the respective horizontal bars obtained by the detection part 13 are inputted to a control signal generation part 14. The reference value of a pattern signal from a pattern signal generation part 12 is inputted to the input terminal 15 of the generation part 14. Then, the scanning start line and the number of width lines of the respective horizontal bars from the detection part 13 are compared with the reference value. When there is difference in the number of lines, a control signal corresponding to phase difference is inputted to a lens control part 58.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection system capable of selecting a screen size of a video screen projected on a screen and projecting a video image picked up by an imaging device in addition to a television image such as a broadcast or package video on the same screen. In a television device, the present invention relates to a focus adjustment device for a video screen projected on a screen from the projection television device.

[0002]

2. Description of the Related Art Recently, television broadcast images and images of movies and theater stages have been magnetically recorded at theaters and event venues.
2. Description of the Related Art A projection television device is used as a device that allows a large number of viewers to simultaneously watch a so-called package video. On the other hand, in lectures and presentations, OH
P (Over Head Projector), slide projectors, etc. are used to display materials, graphics, and images that supplement the lecture presentation on the screen. However, with this OHP or projector, the screen projected on the screen is dark. Therefore, it is necessary to darken the lighting in the venue. For this reason, there has been used a projection device in which an imaging device is combined with a projection television device that does not require dimming the illumination in the venue and that allows a large number of viewers to view a clear and bright screen.

FIG. 5 shows a specific configuration of this projection apparatus.
This will be described with reference to FIG. Note that this projection device will be described using a projection television device using a liquid crystal element as an example. A television video signal is input to a terminal 51a of the switch 51 in the figure. As the TV video signal, a TV broadcast wave received by a receiving antenna (not shown) is obtained through a channel selection device and a video signal reproduction device, or is recorded in a magnetic recording medium in the form of a TV signal. There are video video signals and the like reproduced by the recording / reproducing device, and are hereinafter simply referred to as television video signals. A video signal processing unit 52 is connected to the movable piece 51c of the switch 51. The video signal processing unit 52 includes the switch 1
5 is processed to generate color signals of three primary colors for reproducing a color video. The three primary color signals generated by the video signal processing unit 52 are input to a liquid crystal element panel driving unit 53. The liquid crystal element panel drive section 53 generates horizontal and vertical driving pulses for driving a liquid crystal element panel 54 described later for each of the three primary color signals. The liquid crystal element panel 54 displays a color image on the liquid crystal panel surface by the driving pulse supplied from the liquid crystal element panel driving unit 53. A light source 55 for projecting an image is provided behind the liquid crystal element panel 54, and in front of the liquid crystal element panel 54,
A projection lens unit 56 is provided. The projection light from the light source 55 passes through the liquid crystal element panel 54, and projects an image displayed on the liquid crystal panel 54 onto a screen 57 via a projection lens 56. This projection lens unit 5
By changing the arrangement position of the projection lens in 6,
The size of the video screen displayed on the screen 57 can be arbitrarily set, or the focus of the video screen projected on the screen 57 can be adjusted. For setting the screen size and adjusting the focus, a lens driving unit 59 that slides and moves the position of the projection lens according to a control signal from the lens control unit 58 is provided. The lens control unit 5
8 generates a signal for controlling a driving time and a driving direction of an electric motor or the like built in the lens driving section 59 in response to an instruction input from the input terminal 58a. As a method of inputting an instruction from the input terminal 58a, although not shown, a plurality of screen size switching switches are provided, and by switching the switches, the lens position in the projection lens unit 56 is moved to change the size. And adjusting the focus by finely adjusting the lens position by changing the resistance value.

Further, the projection device incorporates a device for imaging materials, figures, sample products, and the like at lectures or presentations. The imaging apparatus includes an imaging lens unit 60 and an imaging video signal processing unit 61 that photoelectrically converts video light captured by the imaging lens unit 60 to generate a television video signal. The captured video signal generated by the captured video signal processing unit 61 is connected to the terminal 5 of the switch 51.
1b. That is, the movable piece 51 of the switch 51
When c is switched to the terminal 51a, the screen of the television video signal is switched to the terminal 51b, and when it is switched to the terminal 51b, the screen of the captured video signal is projected and displayed on the screen 57.
In the following description, capturing and projecting a material or the like in this manner will be referred to as OHP display for convenience.

When the image screen projected on the screen 57 is switched by the switch 51, the image screen displayed on the screen 57
In step 8, a predetermined screen size is set or the focus is adjusted each time. Of the screen size and the focus adjustment, particularly the focus adjustment is performed on the screen 57.
Of the lens control unit 5
The fine adjustment of the input instruction from the input terminal 58a of No. 8 or the manual driving of the lens drive unit 59 is performed to search for the best focus. For this reason, there is a difference in the best focus point (hereinafter referred to as “just focus”) due to the individual difference of the focus adjuster, or the focus adjustment must be made quickly and just focus every time the projection screen size is changed. If just focus cannot be obtained, the viewer will feel uncomfortable every time the screen size is changed.

[0006]

In a conventional projection television apparatus, when projecting either a television video signal or a captured video signal onto a screen, the screen size is changed and the screen focus is adjusted. Just focus differences may occur due to individual differences of coordinators, or just focus search takes time,
There were issues such as giving viewers discomfort.

SUMMARY OF THE INVENTION An object of the present invention is to provide a focus adjusting device for a projection television which enables a quick and accurate just focus adjustment irrespective of the size of a projected video screen and without causing individual differences between adjusters. I do.

[0008]

According to the present invention, there is provided a video display element for reproducing a television video signal to generate a video screen,
Projection television means for enlarging and projecting a video screen generated on the video display element onto a screen via a projection lens means capable of controlling a projection ratio, and capable of capturing a video screen projected on the screen by the projection television means Image pickup means, an adjustment pattern generation means for generating a signal for displaying an arbitrary reference pattern video screen for focus adjustment on the screen instead of the television video signal, and a signal from the adjustment pattern generation means With this, an arbitrary reference pattern projected on the screen is imaged by the imaging means, a display pattern position displayed on the screen is detected from the imaged video signal, and compared with a reference signal of the adjustment pattern generation means. A shift detecting means for detecting a shift, and a shift signal obtained by the shift detecting means. A focus adjustment apparatus of projection television which is characterized in that to control the serial projection lens unit.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of a focus adjustment device for a projection television according to the present invention. The same parts as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0010] The present invention enables a video screen of either a television video signal or a captured video signal to be projected on a screen, and converts a video signal captured by the imaging device into the same signal form as a television video signal to perform video signal processing. The liquid crystal element panel driving section 53, the liquid crystal element panel 54, the projection lens section 56, the lens control section 58, and the lens driving section 59 are shared by supplying the liquid crystal element panel driving section 53 and the liquid crystal element panel 54. In addition to the OHP display, the imaging lens unit 60 and the imaging video signal processing unit 61 can also capture a video screen projected on a screen, and perform just-focus adjustment based on the captured screen video. It is.

The difference between FIG. 1 and FIG. 5 is that three terminals a1, a2, and a3 are provided in a changeover switch 11 for a signal input to a video signal processing unit 52, and the terminal a1 is provided with the TV video signal. Is input to a terminal a2, and a pattern signal from the pattern generation unit 12 is input to a terminal a2, and an imaging video signal from the imaging video signal processing unit 61 is input to a terminal a3. Further, a phase detection unit 13 to which an image pickup video signal from the image pickup signal processing unit 61 is input, a signal generated by the phase detection unit 13 and the pattern generation unit 12
And a control signal generating unit 14 that compares the reference signal with a control signal and supplies a control signal to the lens control unit 58 based on the comparison result.

In a projection television having such a configuration, it is assumed that a predetermined control signal is given to an input terminal 58a of the lens control section 58 and a video screen of a predetermined screen size is displayed on the screen 57. In this state, the movable piece of the switch 11 is switched to the terminal a2,
A pattern signal for focus adjustment is input from the pattern generation unit 12 to the video signal processing unit 52. The pattern signal from the pattern generator 12 is displayed as an image on the liquid crystal element panel 54 and projected on a screen 57. An example of the shape of the pattern projected on the screen 57 is shown in FIG.

This pattern has predetermined widths and equal widths and lengths above, at the center and below the center of the screen.
The pattern generation unit 12 outputs the horizontal bars x, y, and z of the book as reference signals and displays them on the screen 57. FIG. 2A shows a just-focused state when this pattern shape is displayed on the screen 57.

The pattern displayed on the screen 57 is taken in by the image pickup lens 60 and the image pickup signal processing section 61
Is converted to an image pickup video signal. The captured video signal generated by the captured signal processing unit 61 is input to the phase detection unit 13. The phase detector 13 counts the scanning lines of the horizontal bars x, y, and z based on the vertical synchronization signal of the captured video signal. For example, the horizontal bar x starts scanning from the n1st line, the horizontal bar y starts scanning from the n2th line, and the horizontal bar y starts scanning from the n3rd line, and a predetermined number of lines (indicating the width of the horizontal bar: for example, the horizontal bar z) Has the number of lines of n3 to n30). The line number and the line number indicating the line width of the scanning start line of the horizontal bars x, y, and z are obtained. Each horizontal bar x, y,
z, the scanning start line and the line width are determined by the control signal generator 1
Enter 4 The reference value of the pattern signal from the pattern generation unit 12 is input to an input terminal 15 of the control signal generation unit 14, and the reference value from the pattern generation unit 12 and each horizontal signal from the phase detection unit 13 are input. The scanning start line of the bar is compared with the number of width lines. If there is a difference between the scanning start line and the number of width lines, a control signal corresponding to the difference is input to the lens control unit 58.

Next, FIG. 2B shows a state in which the image screen projected on the screen 57 is out of focus (that is, a state in which just focus is not performed). Horizontal bar x,
y, z, and dotted rectangles x1, y indicating the state of defocus.
1, z1 are shown. If just focus is not performed, the positions and widths of the horizontal bars x, y, and z displayed on the screen 57 by the pattern signal from the pattern generator 12 change as indicated by the dotted lines in the figure. For example, the horizontal bar x is displayed as a dotted rectangle x1 having a width of scan lines n01 to n1 above the horizontal bar x in the figure, and the horizontal bar y is a dotted rectangle y1 having a width of scan lines n02 to n21. And the horizontal bar z is the scan line n
It is assumed that the image is projected as a dotted rectangle z1 having a width of 30 to n31. The image screen displayed on the screen 57 is captured by the imaging lens unit 60, and is converted into an image signal by the image signal processing unit 61. From the captured video signal, the phase detection unit 13 detects a scanning start line of the horizontal bar x1 of the pattern. The detected scanning start line signal is input to the control signal generator 14. The control signal generator 14 compares the reference value of the pattern signal of the horizontal bar x from the pattern generator 12 input to the input terminal 15 with the horizontal bar x1 scanning start line. That is, when the horizontal bar x is in just focus, the scan start line is n1, whereas when the horizontal bar x is not in focus, the scan start line is n01. The scanning start lines n1 and n0
The difference from 1 is the width of the focus shift. Accordingly, the control signal generator 14 generates a control signal corresponding to the difference between the scanning start lines n1 and n01, and generates the control signal.
And a control signal is supplied until the difference between the scanning start lines n1 and n01 disappears. Scan start lines n1 and n01
The point at which the values match is in the just focus state. At this time, when n1-n01> 0, the projection lens unit 5
6 to supply a control signal to shorten the focal length, and n1
If −n01 <0, the control signal is set to supply a control signal that increases the focal length.

In this manner, the scanning start line of the horizontal bar of the reference pattern signal is compared with the scanning start line of the horizontal bar detected from the image signal, and a control signal is generated so that the difference becomes zero. By adjusting the focal length of the projection lens unit 56 via the lens control unit 58 and the lens driving unit 59 based on the control signal, a just-focused video screen can be obtained. In this state, when the switch 11 switches the television image signal from the terminal a1, the image screen of the television image signal can be displayed on the screen 57 in the just-focused state.

In the above description, the scanning start line of the horizontal bar x is used. However, a control signal for focus adjustment is generated using the scanning start line of any horizontal bar or all the horizontal bars. It is apparent that the control signal may be generated on the basis of both signals of the scanning start line and the number of width lines.

Next, another embodiment of the present invention will be described with reference to FIG. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. The difference between FIG. 3 and FIG. 1 is that the captured video signal generated by the captured video signal processing unit 61 is supplied to the control signal generation unit 14 via the distance measurement circuit 21. The operation of this embodiment will be described with reference to FIG.

First, as shown in FIG. 4A, the distance t between the screen 57 and the projection lens unit 56 of the projection television device and the distance t between the imaging lens unit 60 and the screen 57 of the image pickup device are made equal. Set to.
Furthermore, the center point of the projection lens unit 56 and the center point of the screen 57 are arranged on a coaxial line, and the line connecting the center point of the imaging lens unit 60 of the imaging device and the screen 57 is the projection lens unit. It is installed so as to be parallel to the line connecting 56 and the screen 57. Further, the focus of the imaging lens unit 60 of the imaging device is accurately adjusted to the distance t of the screen 57.

Under these conditions, the same three-dimensional pattern as described above by the reference pattern signal from the pattern generator 12 is used.
A pattern image composed of two horizontal bars x, y, z is projected on the screen 57. Each projected horizontal bar x, y, z
When the focus adjustment of the projection lens unit 56 is in the just-focus state, the interval H0 is projected at the same position as shown in FIG. Therefore, the horizontal bar interval h0 of the image screen of the screen 57 projected on the photoelectric conversion element surface of the image screen captured by the imaging lens unit 60 of the imaging apparatus is obtained.
The distance H0 on the screen 57 and the distance h0 between the photoelectric conversion element surfaces are proportional. In the distance measuring circuit 21, for example, the scanning start lines of the horizontal bars x and y are counted, and the difference between the number of scanning lines is detected as the distance, so that the interval H0 can be obtained. The signal of the detected difference in the number of scanning lines is supplied to the control signal generator 14. The control signal generator 14 has a horizontal bar x in the reference pattern signal from the pattern generator 12 to an input terminal 15.
And the interval value signal of y are supplied. The reference interval signal is compared with the scanning line number difference signal from the distance measuring circuit 21. The comparison result is supplied to a projection lens control unit 58, which controls the driving of a lens driving unit 59 to control the projection lens 56.
Adjust the projected video screen from to just focus.

The operation when the image projected on the screen 57 is not in the just focus state will be described with reference to FIG. FIG. 4C shows horizontal bars x, y, and z in the just-focused state, and horizontal bars x1, y1, and z1 indicated by dotted rectangles in the figure showing the defocused state. For example, the horizontal bar x1 indicates that the scanning start line is n
At 10, the scan end line is n1m. Further, the scan start line of the horizontal bar y1 is n20, and the scan end line is n20.
2 m. The difference in the number of lines between the scan start and end lines is the width caused by the focus shift of each of the horizontal bars x and y. A signal having the difference between the number of scanning start lines and the number of ending lines is supplied to the distance measuring circuit 21 to determine the center lines nx and ny of the horizontal bars x and y from the respective line number differences, and calculate the center lines nx and ny from the center lines nx and ny. A line number difference H1 signal is detected. This line number difference H1 signal is output from the control signal generator 1
4 is supplied. The control signal generator 21 receives a reference line number difference H0 between the horizontal bars x and y from the pattern generator 12 input to the input terminal 15 as a reference value. The reference line number difference H0 of this reference value
And a control signal is generated such that the line number difference H1 from the distance measuring circuit 21 becomes equal. The control signal from the control signal generator 14 is transmitted to the projection lens controller 5
8, the lens driving section 59 is driven to adjust the focus of the projection lens section 56, and the projection lens of the projection lens section 56 is slid and adjusted until the focus state is reached.

In this description, the just focus adjustment is performed by detecting the distance between the horizontal bars x and y. However, the distance between the horizontal bars y and z is used, or the distance between the horizontal bars x and y is used. It is clear that the same adjustment can be made by using two distances between the horizontal bar y and the z.

As described above, according to the present invention, a projection television apparatus and an imaging apparatus are provided side by side, and a reference pattern signal for focus adjustment is projected from a pattern signal generating section onto a screen via the projection television apparatus. The reference pattern image projected on the screen is imaged by the imaging device. A difference signal between the scan start lines or the scan lines of the pattern is generated from the captured image, and is compared with a reference scan start line or a signal between scan lines from the pattern signal generator. By the comparison, the projection lens of the projection television apparatus is slid so that the reference scanning start line or the inter-scanning line signal and the scanning start line difference or the inter-scanning line difference signal obtained from the captured image coincide with each other. The focus is adjusted.

Thus, when the size of the projection screen projected from the projection lens unit is changed from the input terminal 58a of the lens control unit 58, the switch 11 is only switched to project the reference pattern signal and the screen is projected. Just focus according to the size can be automatically secured.

In the description of another embodiment of the present invention, the central axis of the projection lens and the screen and the central axis of the imaging lens and the screen are in a parallel state, but the central axis of the projection lens is the center point of the screen. It is also clear that the distance between the reference patterns can be measured by adjusting the center axis of the imaging lens to the center point of the screen.

Further, it goes without saying that the imaging device can be used for OHP display after just focus adjustment. Further, in the above description, a projection type projection television using a liquid crystal element panel is taken as an example, but it is apparent that the invention can also be applied to a projection television using a projection type cathode ray tube.

In the above description, each time the size of the screen projected on the screen is changed, the just-focus adjustment is performed by projecting the reference pattern image from the reference pattern generating section. May change the screen size on the way. In such a case,
In addition to the OHP display camera, a very small imaging camera is provided near the projection lens of the projection television apparatus so that the focus state of the screen screen is constantly monitored, and the viewer's view is displayed on the OHP display screen. Superimposing the reference pattern image on a screen so as not to disturb the viewing, projecting the reference pattern image on a screen, imaging the reference pattern with the focus monitoring camera, and always performing just focus adjustment every time the projection screen size is changed. Is also possible.

[0028]

As described above, according to the present invention, when the screen size projected on the screen is changed, just focus can be obtained automatically and reliably by simply projecting the reference pattern for focus adjustment. In addition, when the screen size is changed during OHP display, the use of an imaging device for monitoring the screen focus separately has the effect that a just-focus state can always be obtained each time the screen size is changed. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a focus adjustment device for a projection television according to the present invention.

FIG. 2 is a plan view illustrating the operation of the present invention.

FIG. 3 is a block diagram showing a configuration of another embodiment of a focus adjustment device for a projection television according to the present invention.

FIG. 4 is a plan view illustrating the operation of another embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional projection television that projects a television video and a captured video on the same screen.

[Explanation of symbols]

11 ... switch, 12 reference pattern generator, 13 phase detector, 14 control signal generator, 15 reference value input terminal, 52
Video signal processing unit, 53 liquid crystal element panel driving unit, 54 liquid crystal element panel, 55 light source, 56 projection lens unit, 58 lens control unit, 59 lens driving unit, 60 imaging lens unit, 61 imaging video signal processing unit.

Claims (4)

[Claims] 1. A video display element for generating a video screen by reproducing a television video signal and enlarging the video screen generated by the video display element to a screen via projection lens means capable of controlling a projection ratio. Projection television means for projecting; imaging means capable of imaging a video screen projected on the screen by the projection television means; and displaying an arbitrary reference pattern video screen for focus adjustment on the screen instead of the television video signal. An adjustment pattern generating means for generating a signal for causing the imaging apparatus to capture an arbitrary reference pattern projected on the screen by a signal from the adjustment pattern generating means; The position of the displayed display pattern is detected, and the reference of the adjustment pattern generating means is determined. No. and compared, and the deviation detecting means for detecting a deviation, the deviation detecting means projection television focus adjusting device which is characterized in that the deviation signal obtained for controlling said projection lens means. 2. The method according to claim 1, wherein the shift detecting unit detects a scan start line of an arbitrary reference pattern projected on the screen imaged by the imaging unit and a scan start line of an arbitrary reference pattern from the adjustment pattern generating unit. 2. The focus adjusting device for a projection television according to claim 1, wherein the shift is detected. 3. The method according to claim 1, wherein the shift detecting unit calculates a difference between a scanning line width of an arbitrary reference pattern projected on the screen imaged by the imaging unit and a scanning line width of the arbitrary reference pattern from the adjusting pattern generating unit. 2. The focus adjusting device for a projection television according to claim 1, wherein the shift is detected. 4. The apparatus according to claim 1, wherein the shift detecting means compares a distance between any reference patterns projected on the screen imaged by the imaging means and a distance between any reference patterns from the adjustment pattern generating means. Claim 1 characterized by the following:
The focus adjusting device for a projection television described in the above item.