JPH069393B2 - Convergence device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a convergence device for automatically adjusting the convergence that statically moves with temperature or the like after adjusting the dynamic convergence when adjusting the convergence of a color television receiver. Is.

2. Description of the Related Art Generally, in a projection type color image receiver that magnifies and projects on a screen by using three projection tubes that emit three primary colors, an incident angle of the projection tube with respect to the screen is different in each projection tube, and thus a color shift occurs on the screen. Occurs. Superposition of these three primary colors, so-called convergence, is a method in which a convergence correction waveform is created in an analog manner in synchronization with the horizontal and vertical scanning periods, and the size and shape of this waveform are changed to adjust. There is a problem in terms of accuracy. Therefore, as a method with high convergence accuracy, for example, Japanese Patent Publication No. 59-8114 is proposed, and further, a digital convergence device capable of shortening the adjustment time and simple operation and capable of automatic adjustment is proposed. ing.

The first method of the conventional convergence device will be described below. FIG. 12 shows a block diagram of a conventional digital convergence device. A convergence correction pattern such as a lattice pattern (shown in FIG. 13) is projected on the screen, and the convergence correction amount for each adjustment point is displayed. The data is digitally written in one frame memory, this data is read and D / A converted, and convergence correction is performed.

First, as shown in FIG. 13, for example, 9 lines in the horizontal direction,
The pattern projection circuit 1 projects a grid pattern of seven columns in the vertical direction. Horizontal signal 14 of this pattern signal
Is a horizontal address counter circuit 3 composed of a PLL circuit and a frequency dividing circuit for a horizontal synchronizing signal 2 synchronized with the scanning of the screen.
Will be supplied and created. Further, the vertical signal 15 is reset by the vertical synchronizing signal 4, and the vertical address counter circuit 5 is reset.
And is supplied to the pattern display circuit 1 and displayed. Next, a cursor key (not shown) on the control panel 8 is used to select a grid point at a position to be corrected and a corrected color, for example, red. The address of a grid point (hereinafter referred to as an adjustment point) selected by the cursor key is stored in the write address generation circuit 7 and supplied to the frame memory 11 via the frame memory control circuit 10, and the correction data of the adjustment point designated by the cursor key Is read from the frame memory 11 and written in the data reversible counter 9. Further, a write key (not shown) of the control panel 8 is operated to increase / decrease the data reversible counter 9 to perform write correction in the frame memory 11. Next, the reading of the convergence correction data written in the frame memory 11 will be described. The horizontal and vertical addresses corresponding to the adjustment points on the screen are created and read by the horizontal address counter circuit 3 which receives the horizontal synchronizing signal 2 and the vertical address counter circuit 5 which receives the vertical synchronizing signal 4 in synchronization with the scanning of the screen. It is supplied to the address generation circuit 6, and the frame memory control circuit 10
The correction data of each adjustment point is read in addition to the frame memory 11 via. Since the frame memory 11 stores only the correction data at the location corresponding to each adjustment point, the vertical interpolation circuit 12 interpolates between the adjustment points in the vertical direction. The vertical interpolation circuit 12 is composed of a subtraction circuit, a coefficient ROM, a multiplication circuit, an addition circuit, etc., and its operation is, for example, the second
The difference is obtained from the correction data of the two adjustment points on the 16th row and the 3rd row by the subtraction circuit, and the weighting coefficient for each scanning line previously written in the coefficient ROM is multiplied by the multiplication circuit,
The result is interpolated by adding the correction data in the second row 17 by the adder circuit. Vertical interpolation circuit 1 that operates as described above
The output of 2 is converted into an analog amount by the D / A conversion circuit 13 to obtain a staircase wave signal. The signal between the adjustment points in the horizontal direction is smoothed by a low-pass filter (not shown) for the correction amount of the adjustment points in each row, amplified, and then supplied to the convergence yoke.

As described above, according to the conventional method, each adjustment point can be corrected independently, so that the convergence correction can be performed accurately.

Next, the second conventional method will be described with reference to FIG. In FIG. 14, 18 is a projection tube, 19 is a projection lens, 20 is a screen, 21 is a deflection yoke, and 22 is a convergence yoke. Reference numeral 23 amplifies the video signal arriving at the video signal input terminal to a required amplitude by a video circuit 24 and drives the projection tube 18. The video circuit 24 operates in the same manner as an ordinary receiver, but during convergence adjustment, a convergence adjustment pattern such as a lattice pattern created by the digital convergence circuit 25 is supplied and displayed.
The convergence circuit 25 is the same as that described in the conventional method 1, and therefore the description thereof is omitted. The deflection circuit 27 and the deflection yoke 21 scan the electron beam of the projection tube 18 with the incoming synchronization signal 26. Although FIG. 25 shows only one projection tube 18, three projection tubes of red (R), green (G) and blue (B) are usually used in a color image receiver. The adjustment pattern detector 28 detects light from a camera or the like, detects the convergence adjustment pattern projected on the screen, and supplies it to the adjustment point detection circuit 29. The adjustment point detection circuit 29 detects the convergence deviation of each adjustment point, changes the correction amount of the digital convergence circuit 25 by the signal of the convergence deviation, and automatically performs the convergence adjustment. Further, as a method of automatically adjusting, there is a method of correcting the convergence deviation using a screen with a photodetector or the like, but the description thereof will be omitted.

Problems to be Solved by the Invention However, in the convergence device having the above-described configuration, the convergence can be adjusted accurately at the time of convergence adjustment, but static convergence deviation occurs after power-on or the ambient temperature of the display device. Occurs. This static deviation is caused by the neck charge of the projection tube,
This is a combination of gun center drift, etc., DC drift of the convergence output circuit, deformation of the convergence yoke due to heat, deflection and changes in the focus system. Therefore, when the convergence is adjusted accurately by the conventional method, it is necessary to adjust the heat run of the display device sufficiently. Further, there has been a problem that a static deviation that occurs after power-on or temperature rise has a function such as static centering and must be adjusted each time. In addition, when a detector is installed in the peripheral part of the screen for detection, complicated signal processing is required for accurate detection, the circuit scale becomes large, and the detector malfunctions or detects due to unnecessary light other than pattern signals. It has a problem that the accuracy is lowered. Further, considering the convergence drift of the device and the fluctuation of the screen phase, there is a problem that a large light receiving area of the detector is required, and a very expensive sensor is required as the detecting portion. Further, in the case of a two-body type system such as a front projection type display, there is a problem that it is difficult to transmit data between the detection unit and signal processing.

In view of such a point, the present invention accurately detects static color misregistration with a simple circuit configuration even when unnecessary light other than the pattern signal is received by the detector provided on the screen, and displays the image An object is to provide a convergence device that automatically performs static convergence correction.

Means for Solving the Problems The present invention is directed to a detection means for detecting a positional deviation by a photoelectric conversion element provided symmetrically with respect to a reference position on a screen, and a detection cycle setting for setting a detection cycle of the detection means. Means, a pattern generating means for generating a pattern signal of each color at a position on the screen where the detecting means can receive light, an output from the photoelectric conversion element arranged in one direction with respect to the reference position from the detecting means, and another direction. By subtracting the output from the photoelectric conversion element arranged at, create a detection signal of opposite polarity to the reference position, detect the maximum value and the minimum value of this subtraction output, Position detecting means for detecting the amount of positional deviation with respect to equal reference positions, storage means for storing the position data from the position detecting means, and amplitude detecting means for detecting the amplitude of the photoelectric conversion output from the detecting means, Amplitude test The detection cycle control means controls the detection cycle of the detection cycle setting means by the detection signal from the output means, and the convergence device controls the convergence correction means by the output from the storage means.

Effect of the Invention With the above-described configuration, when static convergence deviation occurs due to temperature or the like after the convergence adjustment is completed, the photoelectric conversion element symmetrically provided on the screen with respect to the reference position detects the deviation. , Subtracting the output from the photoelectric conversion element arranged in one direction with respect to the reference position from this detector and the output from the photoelectric conversion element arranged in the other direction, the polarities opposite to the reference position Detection signal, the maximum value and the minimum value of this subtraction output are detected, the amount of positional deviation from the reference position where the detection signals of both polarities are equal is accurately detected, and this detection signal is used for convergence correction. By controlling the circuit, detecting the amplitude of the photoelectric conversion output from the detector, and controlling the detection cycle with this detection signal, unnecessary light is displayed on the screen while the image is displayed on the screen. Even if it is incident, accurate automatic static convergence correction can be performed.

First Embodiment FIG. 1 is a block diagram of a convergence device according to a first embodiment of the present invention. In FIG.
Reference numeral 38 is a pattern generation circuit for generating a pattern signal necessary for detecting the convergence deviation, and reference numerals 30 and 31 are detectors provided with photoelectric conversion elements in the peripheral portion of the screen for detecting the convergence deviation with respect to the reference position. Is an amplitude detection circuit for detecting the amplitude of the photoelectric conversion output from the detector, 32 is a position detection circuit for detecting the reference position, which is composed of a maximum value detection circuit 33, a minimum value detection circuit 34 and an adder 35. , 36 is a storage circuit for storing the position data from the position detection circuit 32, 37 is a convergence correction circuit for performing static convergence correction by an output signal from the storage circuit 36, and 42 is a detection cycle setting for setting a detection cycle. A circuit, 43 is a detection cycle control circuit for controlling the detection cycle by the detection signal from the amplitude detection circuit 41. In the same figure, those that operate in the same manner as in the past are indicated by the same numbers and their explanations are omitted.

The operation of the convergence device of this embodiment configured as described above will be described below. The convergence adjustment of the entire screen is performed by the digital convergence circuit 25 or the analog convergence circuit as in the conventional case, and after the adjustment is completed, the pattern generating circuit 38 displays the pattern signal of each color passing through the detectors 30 and 31. 2a) shows a projected screen of the pattern signals 44 and 45 passing through the detectors 30 and 31, and FIG. 2b) c) shows an enlarged view of a part of the screen. Immediately after the convergence adjustment is finished, there is no color shift and the same position is scanned. At this time, the detectors 30 and 31 detect the positional deviation of the pattern signals 44 and 45. The normal detection cycle is determined by the signal from the detection cycle setting circuit 41, and this signal is supplied to the memory circuit 36 and the pattern generation circuit 38 to set the detection cycle. The detector is, for example, a plurality of photoelectric conversion elements (S1 to S1).
S4, S5 to S8), and the detectors 30, 3
The photoelectrically converted signal from 1 is supplied to the position detection circuit 32 to detect the position shift amount with respect to the reference positions X0 and Y0 (center positions of S2 and S3, S6 and S7). In the position detection circuit 32, the outputs from the photoelectric conversion elements arranged in one direction with respect to the reference positions from the detectors 30 and 31 are subtracted from the outputs from the photoelectric conversion elements arranged in the other direction,
A detection signal having polarities opposite to the reference position is created, and the maximum value detection circuit 33 and the minimum value detection circuit 34 of the subtraction output are generated.
The maximum value and the minimum value of the photoelectric conversion output whose polarity changes with respect to the reference position from the detectors 30 and 31 are detected, and the detection signals of both polarities are added by the adder 35 so that both detection signals become equal. The amount of displacement with respect to the reference position is detected.
The position data of each color from the position detection circuit 32 is stored in the storage circuit 3
In step 6, the displacement amount is stored for a certain period. Memory circuit 36
Since the output from is supplied to the convergence correction circuit 37 to control the static deviation amount, the pattern signal is always displayed at a fixed position on the detectors 30 and 31, and the convergence correction is automatically performed. Done. Even if the amount of convergence deviation does not occur, the pattern signal 3
9, 40 are always constant positions, that is, reference positions X0, Y0
The screen phase is automatically corrected so that

The photoelectric conversion outputs from the detectors 30 and 31 are supplied to the amplitude detection circuit 41 to detect the amplitude. The detection signal from the amplitude detection circuit 41 is supplied to the detection cycle control circuit 42, and when the amplitude of the detection signal is large, the detection cycle of the detection cycle is set so as to stop the detection operation set by the signal from the detection cycle setting circuit 42. Have control. Ie detector 3
When unnecessary light other than the pattern signal is incident on 0 and 31, the detection operation is forcibly stopped to prevent the detection error due to the unnecessary light and the convergence deviation due to the deterioration of the detection accuracy.

Next, the screen diagram of FIG. 2B) is used to explain the operation when the convergence shift occurs. The pattern signal after convergence adjustment will be described, for example, when the red pattern signal 46 is shifted upward as shown in FIGS. 2a) to 2b). The color of the pattern signal at this time is switched by a signal from the detection period setting circuit 42 which divides the vertical synchronizing signal from the input terminal 71 to set the detection period, for example, green (hereinafter referred to as G at the first field scanning). A red (hereinafter referred to as R) pattern signal 46 is output from the pattern generation circuit 38 during the second field scanning. G pattern signal 44 at detector 30
And the photoelectric conversion signal obtained by photoelectrically converting the R pattern signal 45 is
As described above, it is supplied to the position detection circuit 32 to detect the amount of displacement with respect to the reference position. The position detection circuit 32 outputs the amount of positional deviation of the difference data (X0-X1) between the reference position X0 and the movement position X1, and this data is stored in the storage circuit 36 as position data. Memory circuit 36
The output signal from is supplied to the R vertical direction static convergence correction circuit of the convergence correction circuit 37,
On the screen shown in FIG. 2b), the red pattern signal 41 is X1.
From X0 to X0 and the static deviation amount is controlled so that the green pattern signal 44 and the green pattern signal 44 are at the same position, static convergence correction can be automatically performed.

To explain the detection and control system of the present invention in more detail, the block diagram of FIG. 3, the operation waveform diagram of FIG. 4, and the operation characteristic diagram of FIG. 5 are used. FIG. 3 shows a detector 30, a position detection circuit 32, a storage circuit 36, and a convergence correction circuit 3.
6, a concrete block diagram of the amplitude detection circuit 41, the detection cycle setting circuit 42, and the detection cycle control circuit 43 is shown. Detector 3
The plurality of photoelectric conversion elements of 0 are composed of point sensors such as photodiodes and phototransistors. The photoelectric conversion signal obtained by photoelectrically converting the pattern signal 44 by the plurality of photoelectric conversion elements (S1 to S4) symmetrically provided with respect to the reference position X0 of the detector 30 is added by the adders 46, 47, 35, the subtractor 48, The position detection circuit 32 including the maximum value detection circuit 33 and the minimum value detection circuit 34 detects the amount of displacement of the detector 30 with respect to the reference position X0 in the same manner as described above. The photoelectric conversion element S1, which is upward with respect to the reference position X0,
The photoelectric conversion signals from S2 are added by the adder 46, and the photoelectric conversion signals from the photoelectric conversion elements S3 and S4 in the downward direction with respect to the reference position X0 are added by the adder 47. Adder 4
The addition outputs from 6, 47 are supplied to the subtractor 48 and subtracted. As the output from the subtractor 48, if the pattern signal is located at the reference position X0 of the detector 30, the adder 46,
Since the signal from 47 has the same amplitude waveform as shown in FIG. 4 a) b), the output from the subtractor 45 is shown in FIG. 4 c).
As shown in, the voltage becomes 0 (V). When the light of the pattern signal received by the detector 30 moves in the arrow direction as shown in FIG. 3, the signals from the adders 46 and 47 also move in the arrow direction as shown in FIGS. The signal amplitude changes. Therefore, as shown in FIG. 4D), the output from the subtractor 48 changes the polarity depending on the position shift direction with reference to the reference position of the detector 30, and changes the signal amplitude depending on the position shift amount. The signal including this position information is the maximum value detection circuit 3
3 and the minimum value detection circuit 34, the maximum value and the minimum value are detected, and the maximum value and the minimum value of this DC potential are added by the adder 35, so that the DC voltage corresponding to the position displacement direction and the position displacement amount is obtained. The place is output from the adder 35. Therefore, when the pattern signal is located at the reference position of the detector 30, the output from the adder 35 has a voltage of 0 as shown in FIG.
(V), the voltage becomes + V1 (V) when the pattern signal moves in the upward direction (arrow direction), and the voltage − when the pattern signal moves in the downward direction (direction opposite to the arrow).
It becomes V2 (V). As shown in the characteristic diagram of the output from the adder 35 with respect to the position on the detector 30 in FIG. 5, a signal including position information in which the reference position X0 of the detector 30 is a voltage 0 (V) is obtained. The output from the adder 35 stores the position data of each color, so that the comparator 49 and the reversible counter 50,
It is supplied to a storage circuit 36 which is composed of 53, 56, memories 51, 54, 57 and D / A conversion circuits 52, 55, 58. The signal including the position information from the adder 35 is the comparator 49.
Is compared with the voltage 0 (V) that is supplied to the reference position and becomes the reference voltage of the reference position. The comparison output from the comparator 49 is supplied to the reversible counters 50, 53 and 56 for the respective colors, the data is increased / decreased in synchronization with the projection of the pattern signals of the respective colors, and the position of the pattern signal of the respective colors becomes the reference position. Outputting data. The increased / decreased data from the reversible counters 50, 53, 56 is supplied to the memories 51, 54, 57 for the respective colors and the data is stored. The digital data from the memories 51, 54 and 57 are supplied to the D / A conversion circuits 52, 55 and 58 for the respective colors to convert the digital amount into an analog amount. Since the timing of data storage is synchronized with the color switching of the pattern signal, the control signal from the detection cycle control circuit 43 is the pattern signal generation circuit 38 and the storage circuit 36.
Is supplied to control the detection operation. The data of each color from the D / A conversion circuits 52, 55, 58 is supplied to the convergence correction circuit 37 and added with the manual data from the input terminal 59 by the adders 60, 61, 62, and then the amplifiers 63, 64, By supplying it to 65 and driving the RGB-H convergence yokes 66, 67, 68,
It automatically controls static convergence.
That is, the pattern signal of each color passing through the detector 30 is
The output voltage from the detector 30 is controlled to the reference position of the detector 30 where the output voltage becomes equal, and the screen phase is automatically adjusted together with the static convergence. Detector 30
The photoelectric conversion output from the peak value detection circuit 69 and the comparator 7
It is supplied to the amplitude detection circuit 41 configured by 0. In the amplitude detection circuit 41, the peak value of the signal photoelectrically converted by the detector 30 is detected by the peak value detection circuit 69, and this detection signal is compared with the comparison voltage Vr by the comparator 70. Comparison circuit 7
The comparison signal from 0 is supplied to the detection cycle control circuit 43, and when unnecessary light other than the pattern signal is incident on the detector 30, the signal from the detection cycle setting circuit 42 is controlled to stop the detection operation. The detection cycle is controlled. Since the subsequent processing is the same as that described above, the description thereof will be omitted.

Similarly, for static convergence adjustment in the left-right direction, a detector 31 provided in the horizontal direction at the bottom of the screen is also used.
Can be done using. Further, correction of blue color (hereinafter referred to as B) is performed in the same manner as red color (R), and therefore description thereof will be omitted.

As described above, according to the present embodiment, the position shift is detected by the detectors 30 and 31 formed of a plurality of photoelectric conversion elements provided on the screen, and this detection signal is supplied to the position detector 32. By detecting the amount of positional deviation with respect to the reference position and controlling the convergence correction circuit 37 by this detection signal, the circuit configuration is simple and unnecessary light other than the pattern signal enters the detector. It is possible to detect accurately without the influence of, and to adjust the fluctuation of the screen phase and static convergence automatically while the image is displayed on the screen. Further, since the detectors 30 and 31 are controlled so as to be located at the reference position, the area of the light receiving portion of the photoelectric conversion element can be reduced, complicated calculation in signal processing is unnecessary, and the processing of the control signal is a DC potential. Therefore, it can be realized with a simple circuit configuration. Further, since the detection cycle is controlled according to the amplitude of the photoelectric conversion output from the detector, accurate convergence correction can be performed without detection malfunction due to unnecessary light other than the pattern signal or deterioration of detection accuracy.

FIG. 6 is a part of a block diagram of a convergence device showing a second embodiment of the present invention. In FIG. 6, the components similar to those in FIG. 1 are omitted. The difference from the configuration in FIG. 1 is that the variations in the gain of photoelectric conversion of the detector 30 composed of a plurality of photoelectric conversion elements are corrected by the adders 46 and 47, and the photoelectric conversion from the adders 46 and 47 is performed. The point is that the signal level is clamped to detect the position. In this system, since the maximum value and the minimum value of the minute photoelectric conversion output are detected to detect the position shift direction and the position shift amount, fluctuations in the DC potential in the position detection circuit 32 and level fluctuations due to unnecessary light occur. Greatly affected by detection accuracy,
Therefore, the gain variation of the photoelectric conversion in the detector 30 is corrected, and the voltage 0 as the reference potential of the photoelectric conversion output is corrected.
The position is detected by clamping (DC regeneration) with (V) to improve the detection accuracy.

The characteristic diagram of FIG. 7 will be used to explain the operation of the convergence device of the second embodiment configured as described above. Reference numerals 46 and 47 are subtractors composed of operational amplifiers 73 and 74, 45 is a subtracter composed of operational amplifier 62, and 71 and 72 are operational amplifiers 75, 77, 76 and 78.
It is a clamp circuit composed of. Generally, adder 46,
The output voltage of 47 is expressed by the following equation.

The output voltage E01 of the operational amplifier 73 is E01 =-(Rf1 / R1 * E1 + Rf1 / R1 * E2) The output voltage E02 of the operational amplifier 74 is E02 =-(Rf2 / R2 * E3 + Rf2 / R2 * E4)
Becomes

The output voltage of the subtractor 48 is expressed by the following equation (R3
= R4, R5 = R6).

E03 = R5 / R3 * (E01-E02).

The photoelectric conversion element S positioned downward with respect to the reference position X0
The photoelectric conversion signals from 3 and S4 are supplied to the operational amplifier 74 through the resistor R2. Further, the photoelectric conversion signals from the photoelectric conversion elements S1 and S2 located above the reference position are supplied to the operational amplifier 73 through the resistor R1 and added. At this time, the resistance ratio of the resistors R1 and R2 is made the same (R1 =
R2) so that the operational amplifier 7
If the pattern signal is located at the reference position, equal photoelectric conversion signals are output from 3,74. However, since the gain variation of the photoelectric conversion characteristics of the photoelectric conversion element of the detector 30 is large, the operational amplifiers 73 and 74 show that the photoelectric conversion characteristics of the photoelectric conversion element are large.
As indicated by the solid line in b), photoelectric conversion signals having different gains are output. Therefore, the reference position between the detector 30 and the signal processing system changes due to the gain difference. Further, when unnecessary light other than the pattern signal as shown by the broken line in FIG. 7 a) b) is incident,
Due to this gain difference, as the output of the subtractor 48 in the subsequent stage, only the gain difference between the pattern signal and the photoelectric conversion signal of unnecessary light is output as shown in FIG. 7 (c), so the detection accuracy is reduced by this unnecessary light. . Therefore, the operational amplifiers 73 and 74 of the adders 46 and 47 are provided with a gain adjusting function for correcting the gain difference in the detector 30 to prevent the detection accuracy from decreasing. That is, by setting the resistance Rf2 of the operational amplifier 74 as a variable resistance so as to be equal to the gain of the photoelectric conversion signal from the operational amplifier 73 shown in FIG. 7a), the detector 30 is made to have a gain as shown in FIG. 7d). Even when unnecessary light is incident, only the pattern signal can be detected with high accuracy. Because the symmetrical position detection is performed by the detectors symmetrically arranged with respect to the reference position X0, the light received by each photoelectric conversion element of the detector has an influence on the light (unnecessary light) having a correlation. Therefore, only the light having no correlation, that is, the pattern signal for detection can be accurately detected.
In addition, the added signal from the adders 46 and 47 is the operational amplifier 7
Clamp circuit 71 composed of 5,76,77,78,
The detection accuracy is improved by being supplied to 72 and stabilizing the DC potential. The drift of the DC potential is caused by the photoelectric conversion characteristics of the operational amplifier and the photoelectric conversion element, and the addition outputs from the adders 73 and 74 have the same amplitude of the photoelectric conversion output but the DC potential is equal as shown in FIG. Similarly, in the case of shifting, the detection accuracy decreases because the reference positions of the detector and the signal processing system are different. The output from the adder 46 shown in FIG. 7 e) and the adder 47 shown in FIG. 7 f)
When the output from the signal is directly subtracted by the subtractor 48, a level shift of V3 + V4 occurs depending on the signal including the position information although it is located at the reference position of the detector as shown in FIG. I will end up. Therefore, clamp circuits 71 and 72 are provided between the adders 46 and 47 and the subtractor 48 to stabilize the DC potential and improve the detection accuracy.
The output from the adder 46 shown in FIG. 7e) is supplied to the feedback type baseline clamp circuit composed of the operational amplifier 75 through the coupling capacitor C1, and the minimum value of the signal is supplied as shown in FIG. 7h). Is clamped to 0 potential. The clamped signal from the operational amplifier 75 is supplied to the operational amplifier 77 to drive the subtraction group 48 in the subsequent stage. Similarly, the signal from the adder 47 shown in FIG. 7 (f) is also supplied to the operational amplifier 76 through the coupling capacitor C2 to clamp the minimum value of the signal to 0 potential. The clamped signal from the operational amplifier 76 is supplied to the operational amplifier 78 to drive the subtraction group 48 in the subsequent stage. Therefore, when the clamped signals from the clamp circuits 71 and 72 are subtracted by the subtraction base 48, the seventh
As shown in FIG. I), a position signal based on the zero potential of the reference position can be accurately obtained. The subsequent processing is the same as that described above, and the maximum value and the minimum value of the signal are detected, and both detection signals are added to perform the position detection.

As described above, according to the present embodiment, the addition bases 46 and 47 correct the gain difference of photoelectric conversion in the detector, and the adder 4
Since the photoelectric conversion signals from 6 and 47 are clamped to detect the position, stable and accurate automatic static convergence correction can be performed even when unnecessary light other than the pattern signal enters the detector. .

FIG. 8 is a part of a block diagram of a convergence device showing a third embodiment of the present invention. In FIG. 8, components similar to those in FIG. 1 are omitted. The difference from the configuration of FIG. 1 is that the amplitude detection circuit 41 performs peak value detection, and the detection signal detects the presence or absence of a photoelectric conversion signal of unnecessary light other than the pattern signal and the pattern signal received by the detector. The point is that the detection cycle is controlled by this detection signal.

The operation diagram of FIG. 9 will be used to explain the operation of the convergence device of the third embodiment configured as described above. The photoelectric conversion signals from the photoelectric conversion elements S1 and S2 are added by the adder 46 in the same manner as described above.
The photoelectric conversion signals from S4 are added by the adder 47. Both photoelectric conversion signals from the adders 46 and 47 are supplied to the adder 80 and added, and the photoelectric conversion signals from the photoelectric conversion elements S1 and S2 and S3 and S4 provided symmetrically with respect to the reference position are output. A photoelectric conversion output is obtained. The peak value of the signal from the adder 80 is detected by the peak value detection circuit 69 composed of the diode D1 and the capacitor C3. The signal from the peak value detection circuit 69 is supplied to the comparators 81 and 82 and compared with the reference potential Vr. The comparator 81 detects the presence or absence of unnecessary light other than the pattern signal received by the detector by comparing it with VrH in which the comparison potential is set high. Further, the comparator 82 detects the presence or absence of the pattern signal received by the detector by comparing it with VrL in which the comparison potential is set low.

The unnecessary light detection signal from the comparator 81 and the pattern signal detection signal from the comparator 82 are supplied to the OR circuit 83,
The detector detects that only the pattern signal is received. The vertical synchronizing signal is input to the input terminal 80 and divided by the counter 84 to generate an address signal for the ROM 85. The address signal from the counter circuit 84 is supplied to the ROM 85 in which the detection cycle is programmed in advance to set the detection cycle. The detection cycle can be arbitrarily set by changing the data content of the ROM. The detection cycle signal read from the ROM 85 and the O
The detection signal from the R circuit 83 is supplied to the switching circuit 86, and the detection cycle is controlled so that the detection cycle signal is generated only when only the pattern signal is received by the detector. The signal whose detection cycle is controlled from the switching circuit 86 is supplied to the pattern generation circuit 38 and the memory circuit 36 to generate the pattern signal of each color and control the operation mode of the memory circuit of each color. As shown in FIG. 9 showing the output voltage from the peak value detection circuit 69 and the detection operation mode, the detection operation is performed only when the output voltage is within the range of VrH to VrL, and the detection operation is stopped in other cases. Are in control. Subsequent processing is the same as that described above, and thus description thereof will be omitted.

As described above, according to this embodiment, the peak value of the photoelectric conversion output received by the detector is detected, and the presence or absence of unnecessary light other than the pattern signal and the pattern signal is detected. By controlling, the position can be detected without detection malfunction due to unnecessary light from the outside, so that accurate automatic static convergence correction can be performed.

FIG. 10 is a block diagram of a convergence device showing the fourth embodiment of the present invention. In FIG. 10, elements similar to those in FIG. 1 are omitted. The difference from the configuration of FIG. 1 is that when the correction data of the memory circuit is at the rising and lower limits, that is, when the operation of the convergence control is not converged, the preset data is controlled. In the case of the field back loop convergence control as shown in FIG. 1, the convergence correction can be accurately performed within the operation range, but when it is outside the operation range, the correction data becomes the upper limit or the lower limit, which causes a large convergence deviation. Will end up. Therefore, when the convergence control is not in the convergence mode, the data is forcibly set to the preset value to prevent the deviation of the convergence.

The operation diagram of FIG. 11 will be used to explain the operation of the convergence device of the fourth embodiment having the above-described structure. FIG. 10 shows a block diagram of the memory circuit 36, in which the signal from the adder 35 is supplied to the input terminal 86 and the comparator 49 compares it with 0 V which is the reference voltage at the reference position. The comparison data from the comparator 49 is the reversible counter 5
0, the data is amplified in synchronization with the projection of the pattern signal of each color, and the data of which the position of the pattern signal of each color is the reference position is output. The data from the reversible counter is supplied to the upper limit / lower limit detection circuit 88 to detect whether the convergence control is in the converged state or the non-converged state. The convergence state detection signal from the upper limit / lower limit detection circuit 88 is supplied to the preset value setting circuit 87, and the data of the reversible counter is set to the preset value in the non-convergence state. FIG. 11 shows the operation mode, and when the data value of the counter is the upper limit (non-converging state 1) and the lower limit (non-converging state 2), it is preset to the central value of the counter, for example. In the converged state, the normal feedback loop control is performed. The data from the reversible counter 50 is stored in the memory 51, and the D / A converter 52 converts the digital amount into an analog amount. Subsequent processing is the same as that described above, and thus description thereof will be omitted.

As described above, according to the present embodiment, the upper and lower limits of the correction data are detected to detect whether the control system is in the converged state or the non-converged state, and the preset value is set only in the non-converged state. It is possible to prevent convergence deviation in the non-convergent state and perform accurate automatic static convergence correction.

Although the present embodiment has been described with respect to the case where a plurality of photoelectric conversion elements are used as a detector for performing symmetrical position detection with respect to the reference position, a position detector having a position calculation function may be used. Needless to say.

Further, in the present embodiment, the case where the position detecting means and the amplitude detecting means are combinedly used has been described, but it goes without saying that the position detecting detector and the amplitude detecting detector may be separately provided. .

Further, in the present embodiment, the case where the photoelectric conversion signal clamping means is performed by the two processing system lines symmetrically provided with respect to the reference position has been described.
It goes without saying that the processing may be performed on the system processing line.

Further, in the present embodiment, the case where the gain difference correction means in the detector is performed by the adder at the post stage of the detector has been described, but two processing systems symmetrically provided with respect to the reference position thereafter are described. It goes without saying that you may go on line.

Further, although the case where the peak value detection is performed as the amplitude detection means has been described in the present embodiment, it goes without saying that the average value detection may be performed.

Further, although the present embodiment has described the case where the data of the memory circuit in the non-converging state is set to the data which is preset in advance, it goes without saying that the correction data at the time of the previous detection may be used.

Further, although the static convergence correction has been described in the present embodiment, a part of dynamic convergence correction may be performed by providing photoelectric conversion elements also in the opposite portions of the peripheral portion of the screen. Further, it goes without saying that it is possible to display that the dynamic convergence adjustment is performed by using a lamp or the like by determining whether it is a dynamic shift and give the dynamic convergence adjustment instruction.

Further, in this embodiment, the superposition of the three primary colors, so-called convergence correction and screen phase correction have been described.
It goes without saying that the screen amplitude and the like may be controlled.

Further, in the present embodiment, the projection type color image receiver has been described for easy understanding, but it goes without saying that the present invention is also effective for the direct view type image receiver.

As described above, according to the present invention, when the convergence accurately adjusted by the digital and analog dynamic convergence circuits is statically displaced due to temperature or the like, a state in which an image is displayed on the screen Since the static convergence and the screen phase can be automatically corrected at the same time, the light receiving area of the photoelectric conversion element of the detector can be reduced and the control signal can be handled with DC potential without complicated calculation in signal processing. Therefore, data transmission and signal processing can be performed with a simple circuit scale. In addition, a detection signal whose polarity changes with respect to the reference position of the detector is created, and the maximum value and the minimum value are detected to detect the symmetry with respect to the reference position. Even when is incident, since the positional deviation can be detected by completely removing the unnecessary light, stable and highly accurate position detection becomes possible. In addition to correcting the gain difference of the photoelectric conversion output from the detector and stabilizing the DC potential, the presence or absence of unnecessary light and the pattern signal is detected, and the detection cycle is controlled by this signal to perform position detection. Even if unnecessary light enters the vessel, there is no detection malfunction, detection accuracy and sensitivity are good, stable and accurate convergence correction can be realized, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram of a convergence device according to an embodiment of the present invention, FIG. 2 is a diagram for explaining the operation of the embodiment, and FIG. 3 is a detailed block diagram of the convergence device of the embodiment. 4 and 5 are operation waveform diagrams and characteristic diagrams of the same embodiment, FIG. 6 is a block diagram of the convergence device of the second embodiment of the present invention, and FIG. 7 is an operation characteristic diagram of the same embodiment.
FIG. 8 is a block diagram of the convergence device according to the third embodiment of the present invention, FIG. 9 is an operation characteristic diagram of the same embodiment, and FIG. 10 is a block diagram of the convergence device according to the fourth embodiment of the present invention. 11 is an operation diagram of the same embodiment, FIG. 12 is a block diagram of a conventional digital convergence circuit, FIG. 13 is an operation diagram of the same circuit, and FIG. 14 is a conventional convergence device for automatically adjusting convergence. It is a block diagram. 30, 31 ... Detector, 38 ... Pattern generation circuit, 3
7 ... convergence correction circuit, 36 ... memory circuit, 3
2 ... Position detection circuit, 46, 47, 35 ... Adder, 4
8 ... Subtractor, 33 ... Maximum value detection circuit, 34 ... Minimum value detection circuit, 41 ... Amplitude detection circuit, 42 ... Detection cycle generation circuit path, 43 ... Detection cycle control circuit, 71, 72 ...
... Clamp circuit, 69 ... Peak value detection circuit, 81, 8
2 ... comparison circuit, 86 ... switching circuit, 87 ... preset value setting circuit, 88 ... upper / lower limit detection circuit, 50, 5
3,56 ... Reversible counter

Claims (1)

[Claims] 1. A display means for displaying an image on a screen, a convergence correction means for correcting a color shift on the screen, and a photoelectric conversion element provided symmetrically with respect to a reference position on the screen. Detecting means for detecting a positional deviation; detecting cycle setting means for setting a detecting cycle of the detecting means; pattern generating means for generating a pattern signal of each color at a position on the screen where the detecting means can receive light; The output from the photoelectric conversion element arranged in one direction with respect to the reference position from the means and the output from the photoelectric conversion element arranged in the other direction are subtracted to create a detection signal having a polarity opposite to the reference position. Position detection means for detecting the maximum value and the minimum value of the subtraction output and detecting the amount of positional deviation from the reference position where the detection signals of both polarities are equal, and the position from the output of the position detection means. De Storage means for storing the data, amplitude detection means for detecting the amplitude of the photoelectric conversion output from the detection means, and detection cycle control means for controlling the detection cycle of the detection cycle setting means by the detection signal from the amplitude detection means. When,
A convergence device, comprising: a control unit that controls the convergence correction unit based on an output from the storage unit.