JP2596116B2 - Image display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device used for a color television receiver, a terminal display of a computer, and the like.

2. Description of the Related Art An image display device having an image screen divided into a plurality of band blocks is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 60-189848 (image display device using a flat cathode ray tube). FIG. 28 is a perspective view of a main part of the apparatus, wherein 1 is an image screen divided into a plurality of band blocks,
Is a phosphor in which the three primary colors of red, green and blue are repeatedly arranged in a stripe pattern in the horizontal direction, 3 is a horizontal deflection electrode having the same number of pairs as band blocks for deflecting the electron beam in the horizontal direction, 4 is Glass substrate supporting horizontal deflection electrode 3, 5
Is a linear cathode that emits the same number of vertically long electrons as band blocks that are independently arranged at equal intervals in the horizontal direction, 6 is a grid that controls the electron beam from the linear cathode 5, and 7 is a linear cathode. 5 is a vertical scanning electrode which is provided adjacent to the linear cathode 5 in the direction opposite to the image screen 1 and is electrically divided so as to perform a vertically elongated vertical scanning in the horizontal direction. The same number is provided. Note that the horizontal direction H and the vertical direction are illustrated to clarify the horizontal and vertical directions of the screen.

Next, in the image display apparatus, a signal processing system until a video signal is applied to the linear cathode 5 will be described with reference to a signal processing system diagram of FIG. Line memory with timing pulse generator 9 based on TV synchronization signal 8
A timing pulse for driving the D / A converter 14 is generated. R, G, B primary color signals (ER, EG, EB) 10
Is converted into a digital signal by the A / D converter 11, and a signal of 1H (one horizontal scanning period) is inputted to the first line memory 12. When all the signals during 1H are input, the signals are transferred to the second line memory 13 at the same time, and the next 1H signal is input to the first line memory 12 again. The signal transferred to the second line memory 13 retains data for a 1H period and is input to the D / A converter 14 to be converted into an analog signal. This analog signal is amplified and applied to the linear cathode 5 shown in FIG. The line memories 12, 13 are used for time axis conversion (serial-parallel conversion).

Assuming that the number of beams (the number of linear cathodes) used for scanning the effective screen area is n, and the area where each beam scans horizontally is 2 triplets (1 triplet is one set of R, G, B phosphor stripes) The effective display period T of the video signal of each R, G, B primary color signal 10 of a certain 1H period is divided into T / n, and the time axis of the video signal of each period is multiplied by n to T,
If the arrangement of the phosphor stripes on the phosphor screen is R → G → B, the primary color signals multiplied by n and extended in the time period in the T period are gated by the gate pulse in the T / 6 period, and ERt →
The signal is converted into a time series signal (parallel signal) of EGt → EBt and input to the linear cathode 5.

In an image display apparatus that displays a color image by vertical and horizontal scanning as described above, in order to display a faithful color image, a video signal of each color corresponding to the color phosphor on which the electron beam is incident (the time-series signal 15). ) Must be input to the linear cathode. As a method thereof, color unevenness correction is performed by controlling the timing of applying the video signal of each color based on the index signal. This conventional color non-uniformity correction circuit will be described with reference to FIG. 30 illustrating the basic principle of the color non-uniformity correction circuit.

As shown in FIG. 30 (a), an index area 17 is provided outside the display area (image effective area) 16 on the image screen 1. This index area 17 is, as shown in FIG.
The index phosphor 95 is applied so that the relative position of the display area 16 with respect to the color phosphor 96 has a predetermined relationship, and the same beam scanning as that of the display area 16 is performed to emit light.
The index phosphor 95 may have the same or different emission wavelength as the color phosphor 96. This index area
The light emitted from 17 is converted into an electric signal by a photoelectric conversion element 18 provided on the front surface of the face plate, and this signal is processed through a BPF (band-pass filter) 24b to perform a process such as waveform shaping to perform an index signal. (A). On the other hand, the light emitted from the blue (B) phosphor in the display area 16 is converted into another photoelectric conversion element similarly provided on the front surface of the face plate.
The signal is converted into an electric signal by 19, and the waveform is shaped through the BPF 24 to be a position signal (b) of the blue (B) phosphor. Here, the reason why the light emitted from the blue (B) phosphor is received is that a signal having a high response speed can be obtained due to the short afterglow.

The phase relationship between the index signal (a) and the B position signal (b) thus obtained is as shown in FIG. 30 (b) if the assembly accuracy of the device is good. Therefore, time differences t1, t2,... From each rising portion of the index signal (a) to the rising portion of the B position signal (b) are measured and stored in the memory 21. This operation is performed beforehand over the entire screen display area without performing the phase correction on the color signals. Then, when actually displaying an image, the time when the time stored in the memory 21 has elapsed from each rising portion of the index signal (a) is referred to as
This is the timing for applying the B color signal. Also, R, G,
For the B color signal, the application timing can be obtained by multiplying the timing signal by three.

As described above, a video signal of each color corresponding to the color phosphor on which the electron beam is incident is applied to the linear cathode, and a faithful color image display is performed.

As a means for reducing color unevenness in and between band blocks, color change is averaged by triangular scanning in which scanning is alternately performed for each scanning line in the screen of FIG. The unevenness is reduced.

However, in the above-described configuration, the scanning direction is reversed by performing the triangular scanning operation, so that signal discrimination and position measurement of a plurality of B position signals in each scanning direction become complicated, and When the amount of change in the color shading correction signal increases, there is a problem that the memory capacity and the circuit scale of the correction circuit increase. Therefore, there is a problem that the circuit scale becomes very large in order to perform highly accurate color unevenness correction, and complicated processing is required.

In view of the foregoing, an object of the present invention is to provide an image display device having a small circuit size and capable of performing highly accurate color unevenness correction in a triangular scanning operation for reducing color unevenness.

Means for Solving the Problems According to a first aspect of the present invention, in a triangular scanning operation in which scanning is performed alternately for each scanning line, an image display area includes an index area provided with an index phosphor, an index area and an image display area. Means for detecting light in one scanning direction to generate a color shading correction signal, means for storing correction data and reading it out in synchronization with an index signal, and means for correcting correction data in one scanning direction in the other scanning direction. Means for obtaining correction data by interpolation.

According to a second aspect of the present invention, in the first aspect of the present invention, the color non-uniformity correction signal creating means measures the position of the reference position and the B position signal synchronized with the index signal, and the index signal missing period. Of the correction data obtained by interpolation calculation.

According to a fourth aspect of the present invention, the index region according to the first aspect of the present invention is configured such that the index phosphor is provided on the phosphor at the center position of each color phosphor cycle in the image display region. .

According to a fifth aspect of the present invention, there is provided an index region in which an index phosphor is provided on a phosphor at the center position of each color phosphor period in the image display region, a plurality of electron guns for emitting light in the image display region, and an image display region. And a plurality of deflecting means for alternately deflecting the electron beam for each scanning line.

According to the first aspect of the present invention, in a triangular scanning operation in which scanning is performed alternately for each scanning line, light in one scanning direction from the index area and the image display area is detected to generate a color unevenness correction signal, This correction data is read out in synchronization with the index signal, and the correction data in the other scanning direction is obtained by interpolation from the correction data in one scanning direction to control the application timing of the video signal, thereby achieving stable and accurate Good color unevenness correction can be performed. In addition, the means for generating the color shading correction signal performs measurement for performing position measurement with respect to the reference position, and prevents missing by adding the previous value data during the missing period of the index signal, so that the correction amount in each scanning direction is reduced. In addition, the color shading correction signal can be set with a small amount of change, as well as a simple circuit configuration with a small memory capacity of the correction circuit.
Stable and highly accurate color unevenness correction can be realized. In addition, a color unevenness correction signal is created by detecting light from the image display area and the index area where the index fluorescent substance is provided on the fluorescent substance at the center position of each color fluorescent substance cycle of the image display area, and this correction data is By controlling the application timing of the video signal by reading it out in synchronization with the index signal, a symmetrical correction signal can be detected at all times. Therefore, interpolation of correction data in the other scanning direction and color unevenness correction are realized with a simple circuit configuration. it can.

According to the fifth aspect of the present invention, the index region in which the index phosphor is provided on the phosphor at the center position of each color phosphor period in the image display region, and the electron beam in the image display region are alternately arranged for each scanning line. By deflecting, even if the screen phase or amplitude changes, color unevenness hardly occurs, and stable and highly accurate color unevenness correction cannot be realized.
This is an image display which is clear, has good color purity, and does not cause uneven division.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 6 show an image display device according to a first embodiment of the present invention. In FIG. 1, reference numeral 31 denotes a color unevenness correction signal generation circuit for generating a color unevenness correction signal from the B position signal from the display area 16 and the index signal from the index area 17, and 32 denotes a color unevenness correction signal generation circuit 31.
A memory interpolation circuit for storing correction data from the memory and performing data interpolation, 37 is a color unevenness correction circuit composed of the color unevenness correction signal generation circuit 31 and the memory interpolation circuit 32, and 33 is correction data from the memory 32. A signal processing circuit for controlling the application timing of the video signal of each color and rearranging the signals corresponding to each image display area in accordance with the image signal, and performs alternate deflection for each scanning line of each image display area Scanning circuit.

In order to describe the color unevenness correction circuit 37 of this embodiment in detail, a block diagram of the color unevenness correction circuit 37 shown in FIG. 2 will be used. In FIG. 2, reference numerals 18 and 19 denote photoelectric conversion elements and reference numeral 24 denotes a band-pass filter, which is the same as that shown in FIG. 27, 28
BPF24 Position detection circuit for waveform shaping and position detection of the extracted signal from I and B, 38 is a phase shift circuit for controlling the pulse phase, and 39 is a phase difference detection circuit for detecting the pulse phase difference , 40 are memories for reading out the correction data in synchronization with the index signal from the position detection circuit 27.

The operation of the color unevenness correction circuit 37 in the horizontal direction of the image display apparatus according to this embodiment configured as described above will be described below with reference to the waveform diagram of FIG. The light emitted from the index phosphor is converted into an electric signal (a) by the photoelectric conversion element 18 and only the signal near the index frequency is extracted by the BPF 24 to obtain an extraction signal (b). The extracted signal (b) is supplied to the position detection circuit 27, and a peak position of the extracted signal (b) is detected to obtain a position signal (c). The position signal (c), that is, the index signal, from the position detection circuit 27 is input to the phase difference detection circuit 38 via the phase shift circuit 32. The phase shift circuit 32 is composed of a monostable multivibrator or the like, and can change the phase within the range of the repetition period as shown in FIG. 3 (d).

On the other hand, the emission of the B phosphor is converted into an electric signal (e) by the photoelectric conversion element 19, and the BP is converted in the same manner as the index signal.
Using F24, only a signal near the index frequency is extracted to obtain an extracted signal (f). This extracted signal (f)
Is supplied to the position detection circuit 28, and the peak position of the extraction signal (f) is detected to obtain the position signal (g). The position detected signal (g), that is, the B position signal is input to the phase difference detection circuit 38.

In the phase difference detection circuit 38, the index signal and B
The phase difference is detected between the pulses of the position signal, and this phase difference is detected.
t1 to t12 are stored in the memory interpolation circuit 32. The phase difference can be detected by a method of starting detection of a clock pulse synchronized with the horizontal synchronizing signal (HD) with an index signal pulse and ending detection with a B position signal pulse. The reading of the correction data from the memory interpolation circuit 32 is performed by the position detection circuit.
The data is read out in synchronization with the index signal from 27, subjected to data interpolation, and supplied to the signal processing circuit 33. The signal processing circuit 33 rearranges the two primary color video signals from the input terminal 35 in accordance with the scanning direction of each image display area and the phosphor arrangement, and applies the signal application timing based on the correction data from the memory interpolation circuit 32. Is controlled. Therefore,
Video signals of each color corresponding to the color phosphors of the entire screen on which the electron beam is incident are applied to the linear cathodes, and a faithful color image is displayed.

Next, the scanning direction and the operation of the color unevenness correction circuit will be described in detail with reference to the waveform diagram of FIG. 4 and the block of FIG. As shown in the enlarged view in the scanning direction on the display area 16 in FIG.
In the first scanning line, the screen is scanned from left to right (right scanning) as indicated by a solid line, and in the second scanning line, scanning is performed from left to right (scanning left) as indicated by a broken line, and this operation is performed alternately. The configuration of the phosphor screen corresponding to the position of the display area 16 shown in FIG. 6A is shown in FIGS. 5B and 5C, and the phosphors 25 for each color are shown in FIG. The index phosphor 26 is shown in FIG. The operation of the color non-uniformity correction circuit in the case of triangular scanning in which alternate scanning is performed for each scanning line will be described below.

First, at the time of scanning the solid line of the first scanning line in FIG.
The light emission of the index phosphor shown in FIG. 3C is converted into an electric signal (f) by the photoelectric conversion element 18, and the pulse shown in FIG. Also, the light emission of the B phosphor in the display area 16 shown in FIG. 2B is converted into an electric signal (d) by the photoelectric conversion element 19, and the pulse shown in FIG. Is done. The index signals shown in the same figure (g) and the B position signals shown in the same figure (e) from the position detection circuits 27 and 28 are supplied to the phase difference detection circuit 39,
A phase difference is detected between the pulses of the index signal and the B position signal, and the phase differences + t21 to + t25 are stored in the memory interpolation circuit 32. In the first scanning line, the B position signal in FIG. 7E is delayed with respect to the index signal in FIG.

Next, when scanning the broken line of the second scanning line in FIG.
The light emission of the index phosphor shown in FIG. 3C is converted into an electric signal (j) by the photoelectric conversion element 18, and the pulse shown in FIG. Also, the light emission of the B phosphor in the display area 16 shown in FIG. 3B is converted into an electric signal (h) by the photoelectric conversion element 19, and the pulse shown in FIG. Is done. The index signals shown in the same figure (k) from the position detection circuits 27 and 28 and the B position signal shown in the same figure (i) are supplied to the phase difference detection circuit 39,
A phase difference is detected between the pulses of the index signal and the B position signal, and the phase differences -t26 to -t30 are stored in the memory interpolation circuit 32. In the second scanning line, the position signal B in the figure (i) leads the index signal in the figure (k). That is, the phase relationship between the index signal and the B position signal is reversed for each scanning line. The positive correction data (+ t21 to + t25) on the first scan line, which has different correction data polarities for each scan line, and the second
Reading from the memory interpolation circuit 32 in which the minus correction data (-t26 to -t30) in the scanning line is stored is performed in synchronization with the index signal from the position detection circuit 27, and is supplied to the signal processing circuit 33. I have. Since the correction data from the memory 40 is synchronized with the index signal, stable color unevenness correction can be performed because the correction data is always synchronized with the index signal even when a screen phase or amplitude fluctuation occurs.

Next, in order to describe the effect of improving color unevenness by triangular scanning, a characteristic diagram of FIG. 5 and a chromaticity diagram of FIG. 6 will be used. In the case of the conventional scanning method in only one direction, when the spot diameter on the phosphor screen in FIG. 5A shifts to the right, the G (green) color becomes B (blue) in the chromaticity diagram shown in FIG. 5) When the color changes in the direction of the black arrow and the spot diameter on the phosphor screen in FIG. 5A shifts to the left, the G (green) color changes to R (red) in the chromaticity diagram shown in FIG. Since the color changes in the direction of the black arrow and the hue in the block changes in the same direction, uneven division is likely to occur. In the present invention, scanning is performed alternately for each scanning line as shown in FIG. 4 (a), and the response on the phosphor screen is changed to the first forward scanning direction of the same scanning line as shown in FIG. Then, a solid line is shown, and a broken line is shown in the second reverse scanning direction. At this time, when the screen amplitude and phase change occur in the image display element and the signal position shifts in the forward direction as shown in FIG. 5 (b), the signal located on the G phosphor is shifted to the left during forward scanning. ,
At the time of reverse scanning, it shifts to the right. That is, in the conventional single scanning method, the hue changes as indicated by the black arrow in FIG.
In the alternate scanning, black arrows in two directions like white arrows shift in the averaged direction. This means that the hue change due to the signal phase change is averaged by alternately scanning the hue change for each band block, thereby reducing color unevenness.

Next, FIG. 7 to FIG. 10 will be used to describe the data interpolation of the memory interpolation circuit 32 in detail. In this data interpolation, correction data in one scanning direction is obtained by interpolation from correction data in one scanning direction in order to eliminate complicated processing of data detection and signal judgment in each scanning direction. Seventh
In the figure, 41 is a pulse selection circuit for selecting a B position signal for each scanning line, 40 is a memory for storing data, and 42 is the other from correction data in the same scanning direction selected from the memory 40. An interpolation circuit 43 for obtaining correction data in the scanning direction of the pulse selection circuit 41 and the interpolation circuit 43
42 is a control input terminal for inputting a control signal for setting a pulse selection and an interpolation period of 42. In FIG. 7, the components that perform the same operations as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The operation diagram of FIG. 8 will be used to explain the image display device of this embodiment in detail. FIG. 3A shows a screen diagram when the contents of the correction data from the memory 40 at the same scanning shown in the conventional example shown in FIG. 3A are displayed in the display area 16, and the correction data (1) is displayed in the first to ninth scanning lines. Since the correlation for each scanning line is high, signal discrimination and position measurement can be performed relatively easily. Conventionally, the correction data of all the scanning lines is stored in the memory 40. The contents of the correction data from the memory 40 at the time of triangular scanning shown in FIG.
When the scanning direction is alternately inverted, the correlation between the correction data becomes low. Therefore, signal discrimination and position measurement for each scanning line become very complicated, so that the circuit scale becomes very large. Therefore, in the present invention, (b)
A circle point in the same scanning direction shown by a solid line in the drawing is a position where the B position signal is detected and this correction data is stored in the memory 40.A square point in a scanning direction different from the scanning direction shown by a broken line is By interpolating from the correction data, the color unevenness correction circuit at the time of triangular scanning is stabilized and improved in accuracy.

Next, in order to explain this operation in detail, a block diagram of the interpolation processing section of FIG. 9 and an operation diagram of FIG. 10 will be used. In the operation diagram of FIG. 10, the vertical axis shows the position in the scanning line direction, and the horizontal axis shows the index signal position, and shows the phase relationship between only the first index signal and the B position signal in the scanning line. On the image display area, the leftmost index signal portion is provided. However, since the scanning direction is reversed, the first index signal position in one horizontal scanning period during right scanning, and the last index signal in the horizontal scanning period during left scanning. Signal position. 46
Is a line for subtracting the correction data for the right scan and the position for the difference period between the left and right alternate scans from the index signal start position for the left scan and performing a linear approximation operation between the lines to obtain the correction data in the left scan direction. An approximation operation circuit 47 is a switching circuit for switching the interpolated left-scan direction correction data from the operation circuit and the right-scan correction data of the detection point from the memory 40 by a control signal applied to the input terminal 43. is there.
By performing triangular scanning on the input terminal 45, signals of ti1 and ti2 having different index signal start positions are input,
The pulse-selected B position signals D1 to D9 are input to the input terminal 44, and these two signals are supplied to the phase difference detection circuit 39 to measure the phase difference. The phase difference measurement circuit 39 outputs an error signal t31 corresponding to the detection points D1, D3, D5, D7, and D9.
The correction data is supplied to the memory 40. The correction data of t31 'to t35' read in synchronization with the index signal from the memory 40 is supplied to a linear approximation operation circuit 46 for performing interpolation. Linear approximation arithmetic circuit
In 46, the following calculations are performed and interpolation points D2, D4, D6,
D8 data is obtained by linear approximation.

Interpolation point data = ti2-(ts + At) Detection point data = ti1 + (t31 to 35) ti1: Index signal start position at right scan ti2: Index signal start position at left scan t31 to 35: Right scan (detection point) Ts: Time difference at the time of left scanning Δt: Change amount obtained by linear approximation from the correction data of the detection point Therefore, when representing the correction data of the interpolation point D2 on the index signal position in FIG. The position shifted from the index signal start position ti2 in the right direction by the ts period and Δt becomes the data of the interpolation D2. Also, when the interpolation data of the interpolation point D4 is expressed, the position shifted from the index signal start position ti2 in the left scan by ts period and Δt in the left direction becomes the data of the interpolation D4. It is. In the above equation, since the shift direction of the correction data is reversed by the alternate scanning in the data processing, the polarity is inverted at the interpolation point and the detection point. However, the shift is performed in the same direction on the screen. The interpolation data from the linear approximation operation circuit 46 and the correction data from the memory 40 are supplied to a switching circuit 47, which performs data switching for each scanning line to obtain interpolated correction data. This correction data is supplied to the signal processing circuit 47 in the same manner as described above, and the application timing of the video signal is controlled to perform color unevenness correction.

As described above, the correction data in one scanning direction is obtained by interpolation from the correction data in one scanning direction, and the projection timing of the video signal of each color is controlled by this data, so that the B position signal and the B signal in each scanning direction are obtained. Since it is not necessary to detect the position of the index signal and determine the signal for each trio trio, it is possible to perform stable and highly accurate color unevenness correction with a simple circuit scale. Further, the interpolation of the correction data can be realized by simple interpolation means such as data shift and linear approximation. Also, by detecting light from the index area and the image display area, a color shading correction signal is created, the correction data is read out in synchronization with the index signal, and the application timing of the video signal is controlled, so that the screen phase and amplitude can be controlled. Can be performed stably and accurately. Also, by performing a triangular scan,
Since the color unevenness can be greatly improved by averaging the hue change, the clock frequency of the color unevenness correction circuit can be reduced and the circuit can be realized with a simple circuit scale.

FIG. 11 to FIG. 14 show a second embodiment of the present invention. The difference from the configuration of the first embodiment is that the color unevenness correction signal is generated by performing position measurement with respect to a reference position in order to perform stable position measurement.
In FIG. 11, reference numeral 48 denotes a reference position setting circuit for setting a reference position for position measurement from the index signal, and reference numeral 49 denotes a position for measuring the phase difference between the reference position signal and the B position signal from the reference position setting circuit. It is a measurement circuit. In FIG. 11, those performing the same operations as in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The operation diagram of FIG. 12 is used to describe the image display device of the present embodiment in detail. FIG. 2A is a diagram showing a conventional position measurement method corresponding to each scanning line and an index signal position. White circles indicate detection points D1 to D9 during right scanning and black circles indicate detection points D1 to D9 during left scanning. . At the detection point D1 of the first scanning line, the position of the index signal positions ti1 and D1 is measured to calculate the correction data t41. At the detection point D3 of the third scanning line, the position of the data t41 of the previous line is measured and the correction data t42 is calculated. Is calculated. At the detection points D5, D7, D9 in the same scanning direction and the detection points D2, D4, D6, D8 in the other scanning directions, the phase difference from the previous line correction data is measured in the same manner. However, when the previous line correction data has a position detection malfunction or omission, the position measurement cannot be performed, so that stable color unevenness correction cannot be performed.

Therefore, in the present invention, the reference position is set in advance from the index signal, and the position measurement of the reference signal and the B position signal is performed to perform stable position measurement. From the position detection circuit 27, the index signal positions ti1 and ti2 in the respective scanning directions in FIGS. The position detection circuit 28
(A) in FIG.
The B position signals D1 to D9 in FIG. The index signal in each scanning direction from the position detection circuit 27 is supplied to the reference position setting circuit 48, and the reference positions tr1 and tr2 in each scanning direction in FIG. The reference position signals tr1 and tr2 from the reference position setting circuit 48 and the B position signals (D1 to D9) from the position detection circuit 28 are supplied to a position measurement circuit 49, which performs position measurement of the phase difference between the two signals. . At the time of right scanning in the same figure (b), there is a phase difference in the right direction of the screen, and the detection point
T1 for D1, t52 for D3, t53 for D5, t54 for D7, and t9 for D9
The phase difference at t55 is measured, and data processing in the plus direction is performed. Also, a phase difference in the right direction of the screen occurs during left scanning, and t56 at detection point D2, t57 at D4, and t5 at D6.
At 8, D8, the phase difference at t59 is measured, and data processing in the minus direction is performed because the scanning direction is different. The phase difference data from the position measuring circuit 49 is stored in the memory 40, and its reading is read out in synchronization with the timing of the index signal from the position detecting circuit 27. This correction data is supplied to the signal processing circuit 47 in the same manner as described above, and the application timing of the video signal is controlled to perform color unevenness correction.

Next, a block diagram of the reference position setting unit shown in FIG. 13 and an operation diagram shown in FIG. 14 will be used to describe in detail the method of setting the reference position. FIG. 13 shows the phase relationship between only the index signal on the screen of each scanning line and the B position signal. 50 is a maximum value detection circuit for detecting the maximum value of the B position signal, 51 is B
Minimum value detection circuit for detecting the minimum value of the position signal, 52
Is a first reference position setting circuit for setting a first reference position in the right scanning direction according to detection signals from the maximum / minimum value detection circuits 50 and 51, and 53 is a maximum / minimum value detection circuit 50, 51 A second reference position setting circuit for setting a second reference position in the left scanning direction in accordance with the detection signal from the control unit; 49 is a position for measuring the phase difference between the reference position in each scanning direction and the B position signal It is a measurement circuit. FIG. 3A shows a position measuring method at the time of right scanning, and FIG. 3B shows a position measuring method at the time of left scanning. The position detection circuit 27 outputs the index signal ti1 in FIG. 7A and the index signal ti2 in FIG. 7B, and the position detection circuit 28 outputs the B position signals D1, D3, D5, and B in FIG. D7
B position signals D2, D4, D6, and D8 shown in FIG.

First, the case of the reference position setting at the time of right scanning shown in FIG. The index signal and the B position signal from the position detection circuits 27 and 28 are the maximum / minimum value detection circuit 5
The signals are supplied to 0 and 51, where the maximum value Dmax and the minimum value Dmin are detected. This signal is supplied to a first reference position setting circuit 52. In the first reference position setting circuit 52, based on the maximum / minimum value detection signal, for example, a reference position tr1 near the maximum value for performing position shift by performing data shift in the same direction or an average value near the average value where the data shift amount is minimum. Is set as the reference position trc1. Similarly, the setting of the reference position at the time of the left scanning shown in (b) is the maximum value Dm from the maximum / minimum value detection circuits 50 and 51.
ax and the minimum value Dmin are detected by the second reference position setting circuit.
Supplied to 53. In the second reference position setting circuit 52, the maximum
Based on the minimum value detection signal, for example, a reference position near the maximum value for performing position measurement by shifting data in the same direction
A reference position trc2 near tr2 and an average value where the data shift amount is minimum is set. The reference signal having a different reference position for each scanning line and the B position signal from the position detection circuit 28 are supplied to the position measurement circuit 49, and the phase difference between the reference signal and the B position signal is measured. When the reference position is set near the maximum value, that is, when the reference signal is located at ti1 and ti2, t61 at the detection point D1, t62 at D3, and t62 at D5 in FIG.
At t63 and D7, the phase difference at t64 is measured, and at D9, the phase difference at t65 is measured. Further, in the same figure (b), the detection point D2 is t66, D4 is t67, and D6 is t6.
At 8, D8, the phase difference at t69 is measured, and the phase difference data is stored in the memory 40.

As described above, the color unevenness correction signal is created by performing the position measurement of the reference signal and the B position signal in which the position measurement for the color unevenness correction is synchronized with the index signal, thereby causing the position detection malfunction and the image display. Even when a pixel of an element is missing, highly accurate position measurement can be performed, so that stable and highly accurate color unevenness correction can be performed.

FIG. 15 to FIG. 18 show a third embodiment of the present invention. The difference from the configuration of the first embodiment is that in order to prevent a malfunction due to a missing detection signal for creating a color shading correction signal and to prevent missing correction data, a missing period of the detection signal is detected, and The point is that the interpolation data is obtained by interpolation. In FIG. 15, reference numeral 54 denotes B of the image display area.
A missing period detecting circuit 55 for detecting the missing period of the B position signal detected by the light emission of the phosphor; 55 is an interpolation for obtaining correction data of the missing period from the correction data from the memory 40 by, for example, previous value scanning line interpolation; Circuit. In addition,
In FIG. 15, components performing operations equivalent to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The operation diagram of FIG. 16 is used to explain the image display device of the present embodiment in detail.

From the position detection circuit 27, the index signal positions ti1 and ti2 in the respective scanning directions in FIGS. In addition, the position detection circuit 28 outputs a B position signal for each scanning line in FIGS. 7A and 7B due to the emission of the B phosphor in the display area.
The index signal in each scanning direction from the position detection circuit 27 and the B position signal from the position detection circuit 28 are
After performing the position measurement of the phase difference between the two signals, the correction data of the phase difference is stored in the memory 40.
The correction data stored in the memory 40 is d1 in the first scanning line, d3 in the third scanning line, d5 in the fifth scanning line, d5 in the seventh scanning line, and d9 in the ninth scanning line in the right scanning direction. The data is stored, and d is stored in the second scanning line in the left scanning direction.
2, d4 is stored in the fourth scan line, d6 is stored in the sixth scan line, and d8 is stored in the eighth scan line. In FIG. 1A, when a missing period tn occurs due to an external factor or a defect of the image display element, it is not possible to detect and write correction data in the missing period, resulting in a missing correction data. Color unevenness occurs.

Therefore, in the present invention, stable color unevenness correction is performed by detecting a missing period and obtaining data of the period by, for example, interpolation of a previous value to generate a color unevenness correction signal. The B position signal from the position detection circuit 28 is a phase difference detection circuit
At the same time as 39, it is also supplied to the missing period detecting circuit 54, and the missing period detecting circuit detects the missing period tn in FIG.
Since the B position signal does not exist in the missing period tn, the phase difference detecting circuit 39 does not detect the phase difference during this period. The correction data for which there is no data of the missing period from the phase difference detection circuit 39 is stored in the memory 40. The correction data of the detection point for each scanning line stored in the memory 40 is calculated by an interpolation circuit.
The correction data for the missing period is supplied to 55 and replaced with the correction data for the previous scanning line to be interpolated. Therefore, the correction data of the fourth to sixth scan lines in the missing period is d2 in the fourth scan line, d3 in the fifth scan line, and d3 in the sixth scan line, as shown in the interpolation period tm in FIG. Interpolated to d2. This means that the correction data for the missing period has been obtained by preceding value interpolation. In FIG. 16, for simplicity of explanation, an interpolation error occurs due to a large change in data for each scanning line. However, no interpolation error actually occurs because the correlation of the correction data for each scanning line is very high. The interpolated correction data from the interpolation circuit 55 is supplied to the signal processing circuit 47 in the same manner as described above, and the application timing of the video signal is controlled to perform color unevenness correction.

Next, a block diagram of the interpolation unit in FIG. 17 and an operation diagram in FIG. 18 will be used to describe in detail a method of interpolating the correction data in the missing period. FIG. 18 shows the phase relationship between only the index signal on the screen of each scanning line and the B position signal. 56 is a buffer memory for holding the correction data from the memory 40 for several horizontal scanning periods, 58 is a coefficient ROM between detection points for performing a linear approximation operation, and 57 is a coefficient ROM from a detection point adjacent to the missing period. Is a linear approximation circuit for obtaining correction data of a missing period from the correction data by linear approximation. First, interpolation by linear approximation of the interpolation point H2 in FIG. 18 will be described. Detection point correction data d1 to d3 and d7 to d9 from the memory 40
Are supplied to the buffer memory 56 and hold data for several H (H is one horizontal scanning period). Buffer memory
The data from 56 is supplied to a linear approximation circuit 57. In the linear approximation circuit 57, data between the detection points is weighted by the coefficient from the interpolation coefficient ROM. At the interpolation point H2, the interpolation point corresponds to two scanning line sections, so the straight line approximation circuit 57 uses the data d3 of the third scanning line and the data of the seventh scanning line.
By adding 1/2 of the difference of d7 to d3, the data of the interpolation point H1 corresponding to the fifth scanning line can be calculated. In addition, since the interpolation points correspond to three scanning line sections at the interpolation points H1 and H3, the linear approximation circuit 57 calculates 1/3 and 2/3 of the difference between the data d2 of the second scanning line and the data d8 of the eighth scanning line. By adding to d2, the interpolation point corresponding to the fourth and sixth scanning lines is obtained.
H1 and H3 data can be calculated. In the setting of the interpolation coefficient ROM 58, a division between detection points is set based on a loss detection signal from the loss period detection circuit 54. Therefore, as shown in FIG. 18, the relationship between the correction data for the missing period tm and the correction signal with a small interpolation error can be created. FIG. 18 shows a formula for calculating each interpolation point.

As described above, the missing period of the B position signal from the image display area is detected, and the correction data for the period is obtained by interpolation to create a color shading correction signal. Even when the B position signal is lost due to a missing pixel, stable correction data is created, so that stable and accurate color unevenness correction can be performed.

FIG. 19 to FIG. 21 show a fourth embodiment of the present invention. The difference from the configuration of the first embodiment is that the change in the large phase relationship between the index signal and the B position signal in each scanning direction is reduced to simplify the signal determination and the data processing at the time of generating the color unevenness correction signal. Therefore, an index phosphor is provided at a center position of each color phosphor cycle to generate a color non-uniformity correction signal. In FIG. 19, reference numeral 61 denotes a color phosphor, reference numeral 60 denotes an index phosphor provided at the center position of a color phosphor cycle (one toiplet cycle), reference numeral 63 denotes an index area constituted by the index phosphor 60, and reference numeral 64 denotes a display. A color unevenness correction signal generation circuit for generating a color unevenness correction signal from the B position signal from the area 16 and the index signal from the index area 63, and 65 is a color unevenness correction signal generation circuit 64
Reference numeral 66 denotes a memory for storing the correction data from the color unevenness correction signal generation circuit 64 and the memory 65. In FIG. 19, components that perform operations equivalent to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The waveform diagram of FIG. 20 is used to explain the image display device of this embodiment in detail. The enlarged view in the scanning direction on the display area 16 is alternately deflected for each scanning line as shown in FIG. 7A, and the first scanning line is from the left to the right of the screen (right scanning direction) as shown by the solid line. In the second scanning line, scanning is performed from the right to the left of the screen (left scanning) as indicated by a broken line, and triangular scanning in which the deflection direction is alternately reversed for each scanning line is performed. The configuration of the phosphor screen corresponding to the position of the display area 16 shown in FIG. 7A is shown in FIGS. 7B and 7C, and the phosphors 61 for each color are shown in FIG. The index phosphor 60 arranged on the phosphor screen at the center position of the color phosphor cycle is shown in FIG. The operation of the color non-uniformity correction circuit in the case of triangular scanning in which alternate scanning is performed for each scanning line will be described below. The basic operation of the color shading correction signal generation circuit 64 is the same as that shown in FIG. 2, and therefore the description will be made with reference to the block diagram of the color shading correction signal generation circuit 31 shown in FIG.

First, at the time of scanning the solid line of the first scanning line in FIG.
The light emission of the index phosphor 60 shown in FIG. 3 (c) is converted into an electric signal (f) by the photoelectric conversion element 18, and a pulse shown in FIG. Also, the light emission of the B phosphor in the display area 16 shown in FIG. 7B is converted into an electric signal in FIG. 7D by the photoelectric conversion element 19, and the position detection circuit 28 at the subsequent stage outputs the pulse shown in FIG. Is output.
The index signal shown in FIG. 9G and the B position signal shown in FIG. 9E from the position detection circuits 27 and 28 are supplied to a phase difference detection circuit 39, and the phase difference between the index signal and the pulse of the B position signal is detected. The phase difference + t71 to + t75 is stored in the memory 65. In the first scanning line, the B position signal in FIG. 7E is delayed with respect to the index signal in FIG.

Next, when scanning the broken line of the second scanning line in FIG.
The light emission of the index phosphor 60 shown in FIG. 7C is converted into an electric signal (j) by the photoelectric conversion element 18, and the pulse shown in FIG. Also, the light emission of the B phosphor in the display area 16 shown in FIG. 2B is converted into an electric signal by the photoelectric conversion element 19 as shown in FIG. 2H, and a pulse signal shown in FIG. Is output. At this time, even if the scanning direction changes, by providing the index phosphor 60 at the center position of the color phosphor period, the right scanning can be performed (f).
And the index signal positions of left scan (j) are the same.
The index signal shown in FIG. 7 (k) and the B position signal shown in FIG. 7 (i) from the position detection circuits 27 and 28 are supplied to a phase difference detection circuit 39, and the phase difference between the index signal and the pulse of the B position signal is detected. The phase differences -t81 to -t85 are detected and stored in the memory 65. In the second scanning line, the position signal B in the figure (i) leads the index signal in the figure (k). That is, the phase relationship between the index signal and the B position signal is reversed for each scanning line.
The positive correction data (+ t71 to + t75) on the first scan line and the negative correction data (-t81 to -t85) on the second scan line from the memory 65 in which the polarity of the correction data is different for each scan line are stored. The reading is performed in synchronization with the index signal from the position detection circuit 27, and the signal processing circuit 33
Supplied to Since the correction data from the memory 40 is synchronized with the index signal, stable color unevenness correction can be performed because the correction data is always synchronized with the index signal even when a screen phase or amplitude fluctuation occurs. Memory 65
Is supplied to the signal processing circuit 47 in the same manner as described above, and the application timing of the video signal is controlled to perform color unevenness correction.

Next, by providing the index phosphor 60 at the center position of the color phosphor cycle, the index signal position is always constant even if the scanning direction is reversed, as shown in FIGS. The operation diagram of FIG. 21 is used to explain that it is very convenient for signal discrimination of position signals and data processing. In the operation diagram of FIG. 21, the vertical axis shows the position in the scanning line direction, and the horizontal axis shows the index signal position, and shows the phase relationship between only the first index signal and the B position signal in the scanning line. On the image display area, the leftmost index signal portion is provided. However, since the scanning direction is reversed, the first index signal position in one horizontal scanning period during right scanning, and the last index signal in the horizontal scanning period during left scanning. Signal position. FIG. 7A shows the phase relationship between the index signal and the B position signal when triangular scanning is performed at the conventional index phosphor position. Since the index phosphor is not arranged at the center position of the color phosphor cycle, the index signal positions ti1 and ti2 are different depending on each scanning direction. Accordingly, the position interval between the first B position signal at the time of right scanning and the first B position signal at the time of left scanning increases, and overlaps with the adjacent B position signal at the time of the second right scanning. This means that it is impossible to discriminate between the first B position signal during left scanning and the second B position signal during right scanning. Further, since the position interval of the B position signal in each scanning direction is large, a large capacity memory is required. However, by arranging the index phosphor 60 at the center position of the color phosphor period as in the present invention, the index signal positions ti1 and ti2 are kept at the same position even if the scanning direction changes as shown in FIG. , The signal discrimination and data processing of the B position signal having different scanning directions can be easily performed only by detecting the correction direction with respect to the index signal position. Correction can be performed.

As described above, by arranging the index phosphor in the index area at the center position of the color phosphor cycle and generating a color nonuniformity correction signal, a large phase relationship between the index signal and the B position signal in each scanning direction can be obtained. Since the change is greatly reduced and the signal discrimination, the position measurement, and the data processing at the time of generating the color non-uniformity correction signal can be easily realized, the color non-uniformity correction with a simple circuit scale and high accuracy can be performed.

Next, in order to simplify the data processing for generating the color shading correction signal, a case where correction data in one scanning direction is obtained by calculation from correction data in one scanning direction will be described in detail with reference to FIG. 23 are used. 22nd
In the figure, 68 is a pulse selection circuit for selecting a pulse of the B position signal only in the same scanning direction, 67 is a phase difference detection circuit for detecting the phase difference between the index signal and the B position signal only in the same scanning direction, 65 is a memory for storing correction data only in the same scanning direction, 69 is an inversion circuit for inverting the polarity of the correction data, and 70 is an arithmetic circuit for calculating correction data in the other scanning direction. In addition,
In FIG. 22, components performing the same operations as those in the fifth embodiment are denoted by the same reference numerals, and description thereof is omitted.

The operation diagram of FIG. 23 is used to explain the image display device of the present embodiment in detail. FIG. 23 (a) shows a conventional case where a B position signal is detected in both scanning directions, and FIG. 23 (b) detects only a B position signal in the same scanning direction according to the present invention and calculates data in the other scanning direction according to the present invention. FIG. In the case of the conventional method (a), detection of the B position signal in both scanning directions and data processing are required, so that signal discrimination and data processing are complicated, and a position detection malfunction or pixel loss of the image display element is caused. When the B position signal is missing, color unevenness occurs due to missing correction data or malfunction.

Therefore, in the present invention, stable color unevenness correction is performed by detecting a B position signal only in the same scanning direction and generating a color unevenness correction signal obtained by calculating data in another scanning direction. The B position signal from the position detection circuit 28 is output from the position detection circuit 27 at the same time as the phase difference detection circuit 39 from the index phosphor provided at the center position of the color phosphor cycle.
With the light emission of 60, ti1 and ti2 having the same index signal position in each scanning direction in FIGS. 7A and 7B are output.
In addition, the position detection circuit 28 outputs a B position signal for each scanning line in FIGS. 7A and 7B due to the emission of the B phosphor in the display area. The B position signal from the position detection circuit 28 is supplied to a pulse selection circuit 68, and selection for each scanning line is performed by a control signal from an input terminal 71. Therefore, from the pulse selection circuit 68, the detection points D1-1, D3-1, D5-1, D7-1, D9-1 of the white circles in FIG.
Of the first B position signal and detection points D1-2, D3-2,.
Only the second B position signals D5-2, D7-2, and D9-2 are output. The index signal in each scanning direction from the position detection circuit 27 and the B position signal from the pulse selection circuit 68 are supplied to a phase difference detection circuit 67, and after measuring the position of the phase difference between the two signals, The correction data is stored in the memory 65. The correction data stored in the memory 65 is t91 at the detection point D1-1, t91 at the detection point D3-1, t92 at the detection point D5-1, and t93 at the detection point D7-1 of the first B position signal. T9 at point D9-1
4 is stored, and the detection point D of the second B position signal is stored.
1-2 at t95, detection point D3-2 at t96, detection point D5-2 at t97,
Data of t98 is stored at the detection point D7-2, and data of t99 is stored at the detection point D9-2. The correction data from the memory 65 is supplied to the arithmetic circuit 70 and the inversion circuit 69, and the undetected correction data in the other scanning direction is obtained. The inverting circuit 69 delays the data by one horizontal scanning period (1H) and inverts the data, and performs an arithmetic circuit 70
Is supplied to The arithmetic circuit 70 creates correction data for all scan lines based on the correction data of the detection point from the memory 65 and the 1H-delayed inversion correction data from the inversion circuit 69. Data obtained by delaying the data at the detection point by 1H and inverting the data is obtained as correction data in the next other scanning direction. Therefore, the correction data of the calculation point indicated by the mark x in the figure (b) output from the calculation circuit 70 is correction data obtained by shifting the correction data of the previous scanning line in the opposite direction with respect to the index signal position. Therefore, the operation point S2 of the first B position signal
-1 for -t90, operation point S4-1 for -t91, and operation point S6-1 for-
At t92, the correction data of -t93 is output at the calculation point S8-1, and at the calculation point S2-2 of the second B position signal, -t95 and the calculation point S4
-2 at -2, -t96 at operation point S6-2, -t97 at operation point S6-2,-
The correction data at t98 is output. As described above, the correction data of all the scanning lines from the arithmetic circuit 70 obtained by calculating the correction data in the other scanning direction from the correction data in one scanning direction is supplied to the signal processing circuit 47 in the same manner as described above. Thus, the application timing of the video signal is controlled to perform color unevenness correction. That is, by correcting the index phosphor to the center position of the color phosphor period, the B position signal at the time of triangular scanning always exists at a position symmetrical with respect to the index signal position. The correction data in the other scanning direction can be obtained by a simple calculation method because the data cannot be detected.

As described above, the index phosphor in the index area is arranged at the center position of the color phosphor cycle, and correction data in the other scanning direction is obtained by calculation from correction data in one scanning direction to create a color shading correction signal. By doing so, the change in the large phase relationship between the index signal and the B position signal in each scanning direction is greatly reduced, and the signal processing and the data processing of position measurement and calculation can be easily realized when creating the color unevenness correction signal. It is possible to perform stable and highly accurate color unevenness correction with a simple circuit scale.

FIGS. 24 to 27 show a fifth embodiment of the present invention. The difference from the configuration of the first embodiment is that in order to reduce color unevenness and to simplify the color unevenness correction circuit, the index phosphor is arranged at the center position of the color phosphor cycle, and the display area is set for each scanning line. Are alternately scanned to reduce color unevenness. In FIG. 24, reference numeral 60 denotes an index phosphor provided at the center position of the color phosphor cycle, reference numeral 73 denotes an index area in which the index phosphor is provided in an area 72 outside the effective screen, and 3 denotes a display area 16 of the effective screen area. The horizontal deflection electrodes alternately deflect the electron beams of the entire screen of the index area 73 in the horizontal direction for each scanning line, and have the same number of pairs as the band blocks. In FIG. 22, those performing the same operations as those in the first and fifth embodiments are denoted by the same reference numerals, and description thereof is omitted.

The waveform diagram of FIG. 25 is used to explain the image display device of this embodiment in detail. The display area 16 and the index area 73 of the effective screen area shown in FIG. 24 are connected to the horizontal deflection electrodes 3 having the same number of pairs as the number of band blocks for alternately deflecting the electron beam of the entire screen in the horizontal direction for each scanning line. Has been
The horizontal deflection electrode 3 is applied with a continuous triangular wave voltage of two horizontal scanning periods shown in FIG. 2A or a stepped triangular wave voltage shown in FIG. 2B to deflect the entire screen in the horizontal direction. I have. Also, the index phosphor 60 in FIG. 11D is provided on the G phosphor which is the center position of the RGB array of the color phosphor 61 in FIG. Even when the scanning direction is different for each scanning line as shown in the figure,
Since the index signal position exists symmetrically in the display area 16 of each band block, the index signal is always output at a fixed position as shown in FIG. The index phosphor i1-1 of the odd scan line in FIG.
1-1, the index phosphor i1-2 corresponds to the signal Si1-2, the index phosphor i1-3 corresponds to the signal Si1-3, and the index phosphor i2-3 of the even-numbered scan line corresponds to the signal Si2-3.
The index phosphor i2-2 outputs a signal Si2-2, and the index phosphor i2-1 outputs an index signal corresponding to the signal Si2-1. Therefore, if this index signal is expressed in correspondence with the index signal position and each scanning line, the figure (f) is obtained, and even if the scanning line changes sequentially, the index signals ti1, ti2, and ti3 at the fixed positions are always output. This means that, as described above, it is very convenient to perform signal discrimination and data processing of the color nonuniformity correction signal, so that a color nonuniformity correction circuit can be realized with a simple circuit scale.

Next, an index area is provided in the area outside the effective screen,
In order to describe in detail the operation when reading from the memory is performed in synchronization with the index signal, the block diagram in FIG. 26 and the waveform diagram in FIG. 27 will be used. In FIG. 26, components performing the same operations as those in the first and fifth embodiments are denoted by the same reference numerals, and description thereof is omitted.

The index signals 74 and 75 for each band block provided in the area outside the effective screen and the index signals and the B position signals from the display areas 76 and 77 are supplied to a color unevenness correction signal generation circuit 64 to generate a color unevenness correction signal. Then, the correction data is stored in the memory 65. The correction data is read out from the memory 65 in synchronization with the detected index signal. The correction data from the memory 65 is supplied to the signal processing circuit 47 in the same manner as described above, and the application timing of the video signal is controlled to perform color unevenness correction. Further, the triangular scanning circuit 34 performs the same operation to generate a triangular waveform for alternately deflecting each scanning line. In the case where the index signal processed by the color shading correction signal generation circuit 64 is as shown in FIG. 6A and the B position signal is as shown in FIG. 6B, the correction data stored in the memory 65 is a phase difference component between the two signals. Is stored. Therefore, in the first scan line, the correction data d11, d12, d1
3, the correction data d14, d15, and d16 are stored in the memory 65 in the second scanning line. Also, the deflection waveform from the triangular scanning circuit 34 at this time is shown in FIG. 11C, which is in the triangular scanning mode in which the scanning direction is reversed for each scanning line. In the case of the index signal shown in FIG. 7A, when a phase change Δt1 occurs in the scanning direction as shown in FIG. The timing is as shown in FIG. (A)
In the index signal shown in the figure, the first direction is shifted as shown in FIG.
When a phase change Δt2 occurs in the reverse scanning direction on the scanning line and a phase change Δt3 occurs in the scanning direction on the second scanning line, the timing of the correction data read from the memory 65 is as shown in FIG. That is, since the correction data is read out in synchronization with the phase of the index signal for each H from the index area 74 provided outside the screen display area, the index signal shown in FIGS. Even when the timing changes, data whose correction data is shifted with reference to the index signal position is always read. Therefore, since the phase relationship between the index signal and the B position signal is always constant, color unevenness does not occur.

As described above, a panel configuration in which an index area in which an index phosphor is arranged at the center position of a color phosphor cycle is provided outside an effective screen, and reading of correction data is performed in synchronization with an index signal, thereby improving the screen phase. And even when the amplitude fluctuates, stable and highly accurate color unevenness correction can be performed. Further, in the panel configuration of the image display element, it can be easily realized only by changing the positions of the index area and the index phosphor.

In the first to fifth embodiments, the description has been given of the case where the image display device uses the flat-plate type cathode ray tube. However, other image display devices may be used.

In the first to fifth embodiments, the case where the application timing of the video signal is controlled as the color unevenness correction means has been described. However, the application timing may be controlled by the deflection speed.

In the first embodiment, linear approximation has been described as an interpolation method. However, another interpolation method may be used.

In the first, second, and fourth embodiments, the processing method between the correction data has been described as the interpolation means.
Processing may be performed using the position signal.

Further, in the third embodiment, the case where the missing period is detected by the B position signal has been described, but the missing period may be detected by detecting the beam current.

Further, in the fourth embodiment, the index phosphor is changed to RG.
Although the case where the phosphor is arranged on the G phosphor positioned at the center of the B phosphor cycle has been described, any color phosphor may be disposed as long as it is located at the center phosphor position of one triplet cycle.

Further, in the fourth embodiment, the calculation between the scanning lines has been described in the case of performing the preceding value interpolation. However, other calculations may be performed.

In the fifth embodiment, the case where the reference index area is provided at the upper part of the screen has been described. However, the reference index area may be provided at another position outside the effective screen.

Effects of the Invention As described above, according to the first aspect of the present invention, color unevenness can be significantly reduced, and stable and accurate color unevenness correction can be realized even when the screen phase or amplitude fluctuates. At the same time, color non-uniformity can be corrected with high accuracy by detection and data processing only in the same scanning direction, so that it can be realized with a simple circuit configuration.

According to the second aspect of the present invention, stable color unevenness correction can be realized by always performing stable position measurement.

According to the third aspect of the present invention, stable correction data is created even when the B position signal is lost due to a position detection malfunction or a missing pixel of the image display element, so that stable and accurate color unevenness correction is performed. be able to.

According to the fourth aspect of the present invention, since signal discrimination, position measurement, and data processing can be easily realized when a color unevenness correction signal is generated, it is possible to perform stable and accurate color unevenness correction with a simple circuit scale. Can be. In addition, high-precision color non-uniformity correction can be performed by detecting only one scanning direction and data processing, and the amount of change in correction data in each scanning direction is greatly reduced, realizing a very simple circuit configuration with a small memory capacity. it can.

According to the fifth aspect of the invention, it is possible to reduce color unevenness and achieve stable image display with a very simple panel configuration, and the practical effect is large.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image display device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a detailed configuration of a color unevenness correction circuit according to the embodiment, and FIGS. FIGS. 5 and 6 are characteristic diagrams of the embodiment, FIG. 7 is a block diagram of an interpolation processing system in the embodiment, FIG. 8 is an operation diagram in the embodiment, and FIG. FIG. 11 is a block diagram showing a detailed configuration of the interpolation circuit in the embodiment,
FIG. 10 is an operation diagram of the embodiment, and FIG. 11 is a second embodiment of the present invention.
FIG. 12 is a block diagram of an image display device in the embodiment, FIG. 12 is an operation diagram in the embodiment, FIG. 13 is a block diagram of a reference position setting circuit in the embodiment, FIG. 14 is an operation diagram in the embodiment, FIG. 15 is a block diagram of an image display device according to a third embodiment of the present invention, FIG. 16 is an operation diagram of the third embodiment, FIG. 17 is a block diagram of an interpolation circuit of the third embodiment,
18 is an operation diagram of the same embodiment, FIG. 19 is a block diagram of an image display device according to a fourth embodiment of the present invention, FIG. 20 is an operation waveform diagram of the same embodiment, and FIG. FIG. 22 is an operation diagram in the example, FIG. 22 is a block diagram of an interpolation circuit in the embodiment, FIG. 23 is an operation diagram in the embodiment, FIG. 24 is a block diagram of an image display device in a fifth embodiment of the present invention, FIG. 25 is an operation waveform diagram in the embodiment, FIG. 26 is a block diagram of a color unevenness correction circuit in the embodiment, FIG. 27 is a waveform diagram in the embodiment, and FIG. 28 is divided into a plurality of band blocks. 29 is a perspective view of an image display device having an image screen, FIG. 29 is a signal processing system diagram of the conventional image display device, FIG. 30 is an operation diagram of a color unevenness correction circuit of the conventional image display device, and FIG. FIG. 3 is a configuration diagram of a phosphor screen of the image display device. 1 ... image screen, 17, 73 ... index area,
16: Display area, 61: Color phosphor, 60: Index phosphor, 31: Color unevenness correction signal generation circuit, 37 ... Color unevenness correction circuit, 18, 19 ... Photoelectric conversion element, 32 ... Memory interpolation circuit, 65 ... Memory, 33 ... Signal processing circuit, 34 ... Triangle scanning circuit, 42, 55 ... Interpolation circuit, 39 ... Phase difference detection circuit, 48 ... Reference position setting circuit, 49 ... Position measurement circuit, 54
… Missing detection circuit, 70… Operation circuit.

Claims (5)

(57) [Claims] An image display element having a plurality of image display areas; an index area in which an index phosphor is provided in the image display area; and a plurality of electron beam deflection elements for alternately deflecting an electron beam in the image display area for each scanning line. Deflecting means,
Means for detecting light in one scanning direction from the index area and the image display area to create a color shading correction signal,
Means for reading out the correction data in synchronization with the storage and index signals, and obtaining the data in the other scanning direction by interpolation, controlling the application timing of the video signal of each color by the correction data, and corresponding to each of the image display areas. An image display device comprising: means for performing serial-parallel conversion for applying the parallel signal to the cathode of the image display element. 2. The image display according to claim 1, wherein said color unevenness correction signal creating means measures a position between a reference position synchronized with the index signal and a B position signal from the image display area. apparatus. 3. The color unevenness correction signal creating means according to claim 1, wherein a missing period of the detection signal from the image display area is detected, and correction data in the period is obtained by interpolation. Image display device. 4. The image display device according to claim 1, wherein the index region is provided with an index phosphor on the phosphor at the center position of each color phosphor period in the image display region. 5. An image display area provided with a phosphor screen in which phosphors are repeatedly arranged in sequence, and an index area in which an index phosphor is provided on a phosphor at a center position of each color phosphor cycle of the image display area. A plurality of electron guns for emitting light in the image display area; a plurality of deflection electrodes for alternately deflecting the electron beam in the image display area for each scanning line; An image display device comprising means for generating a signal corresponding to a body arrangement and applying the signal to a cathode of the image display element.