JPH0355989A - Picture display device - Google Patents

Abstract

PURPOSE:To reduce the deterioration in the spot characteristic especially in the horizontal direction and to attain sharp picture display with excellent color purity without uneven division by using a deflection means to deflect continuous and discontinuous deflection waveforms while they are being switched and modulating the scanning speed of only each fluorescent material position with the discontinuous deflection. CONSTITUTION:A deflection circuit 31 generates a modulation signal to correct the deflection speed corresponding to each color fluorescent material position, that is, the scanning speed corresponding to a correction data from a storage circuit 28. A deflection waveform from the deflection circuit 31 is applied to horizontal deflection electrodes (3-1)-(3-n) to improve a considerable spot characteristic with the continuous scanning of each picture display area and the scanning speed modulation limited to a part of each color fluorescent material position.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image display device used in color television receivers, computer terminal displays, and the like.

2. Description of the Related Art An example of an image display device having an image screen divided into a plurality of band blocks is disclosed in Japanese Patent Application Laid-Open No. 1898-1898.
A device disclosed in Japanese Patent No. 48 (Image display device using a flat cathode ray tube) is known. Figure 15 is a perspective view of the main parts of the device; 1 is an image screen divided into a plurality of band blocks; 2 is an image screen in which the three primary colors of red, green, and blue are repeatedly arranged in stripes in the horizontal direction; phosphor,
3 is a horizontal deflection electrode having the same number of pairs as band blocks for horizontally deflecting the electron beam, 4 is a glass substrate that supports the horizontal deflection electrode 3, and 5 is a band arranged independently at equal intervals in the horizontal direction. A linear cathode that emits the same number of long electrons in the vertical direction as the blocks, 6 a grid that controls the electron beam from the linear cathode 5, 7 a linear cathode 5 in the opposite direction to the image screen 1; cathode 5
These vertical scanning electrodes are electrically divided and provided close to each other to perform elongated vertical scanning in the horizontal direction, and are usually provided in the same number as the number of horizontal scanning lines. Note that in order to clarify the horizontal and vertical directions of the screen, a horizontal direction H1 and a vertical direction V are illustrated.

Next, regarding the above-mentioned image display device, the signal processing system until the video signal is applied to the linear cathode 5 will be described in the 16th section.
This will be explained using figures. Based on the TV synchronization signal 8, the timing pulse generator 9 connects the line memory 12, 13 and D/A.
A timing pulse is generated to drive the converter 14. Three primary color signals of R, G, B (ER, EG, EB)
10 is converted into a digital signal by an A/D converter 11,
The IH (one horizontal scanning period) signal is stored in the first line memory 1.
Enter 2. When all the signals between IHs are input, the signals are simultaneously transferred to the second line memory 13 and transferred to the next IH.
The signal is also input to the first line memory 12. Second
The signal transferred to the line memory 13 is held as data during the IH 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. Note that the line memories 12 and 13 are used for time axis conversion (serial-parallel conversion).

The number of beams used to scan the effective screen area (the number of linear cathodes) is n1, and the area horizontally scanned by each beam is 2 triplets (one triplet is a set of R, G, and B phosphor stripes). Then, R, G for a certain IH period
,B Effective display period T'j of the video signal of each primary color signal 10
Divide into t T / n, multiply the time axis of the video signal of each period by n and set it as T. If the arrangement of phosphor stripes on the phosphor screen is R-+G → B, then multiply by n. Each primary color signal whose time axis has been expanded in the T period is gated with a gate pulse of the T/6 period, converted into a time series signal (parallel signal) of ERt→EGt+EBt, and inputted to the linear cathode 5.

In an image display device that displays a color image by vertical and horizontal scanning as described above, when trying to display a faithful color image, the video signal of each color (time series signal 15) corresponding to the color phosphor on which the electron beam is incident ) must be input to the linear cathode. As a method, color unevenness correction is performed by controlling the timing of applying video signals of each color based on the index signal. This conventional color unevenness correction circuit will be explained using the block diagram shown in FIG. 17 showing the basic principle of the color unevenness correction circuit.

As shown in FIG. 17 (18), an index area 17 is located outside the display area (image effective area) 16 on the image screen 1.
will be established. As shown in FIG. 18, this index area 17 is coated with an index phosphor 25 such that the relative position with the color phosphor 26 of the display area 16 is in a predetermined relationship, and the same beam scanning as that of the display area 16 is performed. By doing this, it will emit light. Index phosphor 25 is color phosphor 2
The light emitting wavelength may be the same as that of 6, or may have a different emission wavelength.

The light emitted from this index area 17 is converted into an electrical signal by a photoelectric conversion element 18 provided on the front surface of the face plate, and this signal is passed through a bandpass filter BP.
It passes through F24A and undergoes processing such as waveform shaping to become an index signal (A).

On the other hand, the light emitted from the blue (B) phosphor in the display area 16 is converted into an electric signal by another photoelectric conversion element 19 similarly provided on the front surface of the face plate, and the waveform is shaped through the BPF 24. Then, the position signal of the blue (B) phosphor (
b). The reason why the light emitted from the blue (B) phosphor was received here is that a signal with a fast response speed can be obtained due to the short afterglow.

If the assembly accuracy of the device is good, the phase relationship between the index signal (A) and the B position signal (X) obtained in this way will be as shown in FIG. Therefore, the time differences tl, t2 from each rising part of the index signal (a) to the rising part of the B position signal (b),...
... is measured and stored in the memory 21. This work is performed in advance over the entire screen display area without performing phase correction on the color signals. When actually displaying an image, the timing at which the B color signal is applied is set at the time when the time stored in the memory 21 has elapsed from each rising edge of the index signal (a).

Furthermore, for the R, G, and B color signals, the application timing can be obtained by multiplying this timing signal by three.

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

Problems to be Solved by the Invention However, in the above configuration, since a time-series signal (parallel signal) obtained by expanding the time axis of the three primary color signals is supplied to the linear cathode, the response speed of the time-series signal (rise, However, due to the high-brightness spot characteristics of flat cathode ray tubes (falling characteristics) and the high-brightness spot characteristics of flat cathode ray tubes, there was a problem in that unevenness in division, such as unevenness in brightness and color, occurred.

In view of this, the present invention improves the spot characteristics at each phosphor position by continuously scanning the electron beam in the image display area and discontinuously modulating the deflection speed only at each phosphor position. It is an object of the present invention to provide an image display device that does not cause division unevenness such as brightness unevenness or color unevenness.

Means for Solving the Problems In order to achieve the above object, an image display device of the present invention includes a cathode that emits an electron beam, a deflection means that deflects the electron beam from the cathode according to a deflection signal, and a plurality of An image display device having an image display area, an index phosphor provided in each image display area, and an image display element in which an image is formed by impinging an electron beam on the phosphor in the image display area. , a color unevenness correction signal generating means for generating a correction signal for color unevenness correction by detecting light from the index phosphor in the index area and light from the phosphor in the image display area; Conversion means converts the input video signal from serial to parallel and supplies it to the cathode, and creates a discontinuous signal that modulates the scanning speed of the phosphor portion based on the correction signal, superimposes it on the deflection signal, and supplies it to the deflection means. A deflection circuit is provided.

Effect According to the above configuration, the deflection means is deflected by switching between continuous and discontinuous deflection waveforms, and the discontinuous deflection modulates the scanning speed of only each phosphor position, thereby improving the spot characteristics, especially in the horizontal direction. The purpose of this invention is to reduce the deterioration of the image and display images that are clear, have good color purity, and are free from division unevenness. Furthermore, by reading out the color unevenness correction data in synchronization with the index signal, stable color unevenness correction becomes possible. Furthermore, even more stable image display can be achieved by controlling the switching of the deflection waveform so that it becomes a continuous sawtooth wave when creating a color unevenness correction signal and a staircase wave when projecting an image.

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

FIG. 1 is a block diagram of an image display device according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an image screen, which is similar to that in FIG. 15. 10 is an input terminal for inputting three primary color video signals (ER, EG, EB); 2
7 is a color unevenness correction signal creation circuit for detecting light from the index area 17 and the display area 16 and creating a color unevenness correction signal; 28 is a storage circuit for storing data of the color unevenness correction signal; 29 is a memory circuit for storing data of the color unevenness correction signal; In order to make the serial video signal of each color correspond to each image display area, time axis conversion is performed, and in order to make it correspond to the three primary colors of each image display area, each color is converted using the correction data. 30 is an amplifier circuit for amplifying the serial signal; 5-1 to 5-n are linear cathodes to which the video signal from the amplifier circuit 30 is applied; 8
31 is an input terminal for inputting a synchronization signal, and 31 is a continuous horizontal sawtooth waveform or a memory circuit 28 according to the input synchronization signal.
3-1 to 3-n are deflection circuits for creating a deflection signal of a horizontal deflection waveform of a discontinuous staircase waveform in response to a read clock signal from the deflection circuit 31, to which the horizontal deflection waveform from the deflection circuit 31 is applied. This is a horizontal deflection electrode.

The operation of the image display device of this embodiment configured as described above will be explained below using the waveform diagrams of FIGS. 2 and 3. Three primary color video signals (ER, EG, EB) shown in FIG. time axis conversion and rearrangement of each color signal are performed.In other words, T
Time axis conversion and rearrangement of each color signal are performed so that the two-period signal becomes the t2 period as shown in Figure 2 (bl).
The T3 and T4 periods shown in FIG. 2(a) correspond to the t3 and t4 periods shown in FIG. 2(C), and the T5 period corresponds to the t3 and t4 periods shown in FIG. 2(td).
5 periods, Tl, T6, T7. During the no-signal period T8, a no-signal parallel signal is created. A parallel signal from the serial-parallel conversion circuit 29 is applied to the linear cathodes 5-1 to 5-n of each block.

A synchronizing signal shown in FIG. 3 (al) is input to the input terminal 8. This synchronizing signal is supplied to the deflection circuit 31, and is converted into a continuous deflection waveform and a discontinuous deflection waveform corresponding to each image display area. First, the former continuous deflection waveform is generated by creating the sawtooth waveform shown in Fig. 3 (bl) from the synchronization signal shown in Fig. 3 (al), as in a conventional television receiver. Created.

Next, a case will be described in which a discontinuous deflection waveform is generated.

The correction data from the color unevenness correction signal generation circuit 27 is stored in the storage circuit 28, and from this storage circuit 28, the correction data corresponding to the application timing of the parallel signal is sent to the deflection circuit 3.
1. In the deflection circuit 31, in response to the correction data from the storage circuit 28, a modulation signal shown in FIG. This modulated signal is shown in Figure 3 (b
By superimposing it on the continuous sawtooth waveform shown in l,
FIG. 3 (A staircase waveform shown by fl is created. Deflection circuit 3
The deflection waveform from 1 is applied to the horizontal deflection electrodes 3-1 to 3-n, and by continuous scanning of each image display area and scanning speed modulation limited to the portion of each color phosphor position, as shown in FIG. (g) ni fruit! (deflection due to signal ff>) and the wavy line (signal (
As shown in (deflection due to bl), the spot characteristics can be significantly improved.

Generally, image display elements have specific spot characteristics, so that the beam response on the phosphor screen has a large spot diameter and a slow pulse response. Figure 3 (The solid line shows the beam response on the phosphor screen when partial scanning speed modulation is not performed. Due to the spot characteristics, the pulse width is wide and becomes φ1, and it is incident on the adjacent R and H phosphors. This causes a decrease in color purity and a decrease in brightness due to a decrease in the aperture ratio of the G phosphor.
The dashed line l indicates the beam response on the phosphor screen when partial scanning speed modulation is performed during the period of the G phosphor position, as shown in Figure 3+fl, and the scanning speed at the G phosphor position is By controlling in the direction of slowing down, the pulse width φ2, which is smaller than the pulse width φ1 shown in the solid line in FIG.
becomes. Therefore, an image with good color purity can be displayed without being incident on the adjacent R and B phosphors. Furthermore, since the aperture ratio of the G phosphor is improved, it is possible to achieve higher brightness, and because there is relatively little change in brightness even if the phase of the parallel signal changes, it is possible to display stable divided images with less uneven brightness. .

Next, a method for creating a discontinuous deflection waveform will be explained in detail with reference to FIGS. 4 to 6. FIG. 4 shows a detailed block diagram of the color unevenness correction signal generation circuit 27 and the deflection circuit 31. In FIG. 4, components similar to those in FIG. 1 are denoted by the same reference numerals and detailed explanation thereof will be omitted. In FIG. 4, 18.19 is a photoelectric conversion element, and 24a and 24b are bandpass filters (B P
F), 33.34 is a position detection circuit for detecting the position by shaping the waveform of the extracted signal from the extraction circuit 36.37, 20
is a phase difference detection circuit for detecting the phase difference of the position signals from the position detection circuits 33 and 34, and 36 is for creating a continuous deflection waveform (sawtooth waveform) signal (Fig. 3 (b)) from the synchronization signal. 35 is a discontinuous waveform producing circuit for producing a discontinuous waveform signal (Fig. 3 {e}) in response to a parallel signal readout clock;
8 is a switching circuit for turning on and off the discontinuous waveform signal from the discontinuous waveform switching circuit 35 to a continuous deflection waveform signal; 37 is the waveform of the continuous waveform switching circuit 36 and switching circuit 3;
This is an addition circuit 37 for adding the waveforms from 8 to 8.

A method of creating a color unevenness correction signal will be explained using the waveform diagram of FIG. 5. The light emitted from the index phosphor is converted by the photoelectric conversion element 18 into an electrical signal shown in ta+ in FIG.
At F24a, only the signals near the index frequency are extracted, and the extracted signal shown in FIG. 5(b) is obtained. This fifth
The extracted signal shown in FIG. 5 (bl) is supplied to the position detection circuit 27, and the peak position of the extracted signal is detected to obtain the index signal shown in FIG. 5 (Cl).

On the other hand, the light emitted from the B phosphor is emitted by the photoelectric conversion element 19 as shown in Fig. 5+e.
), and in the same manner as the index signal, only the signals near the index frequency are extracted using the BPF 24, to obtain the extracted signal shown in FIG. 5 if). This extracted signal is supplied to the position detection circuit 34, and the peak position of the extracted signal is detected to obtain the B position signal shown in FIG. The B position signal is input to the phase difference measurement circuit 20.

In the phase difference measurement circuit 20, after adjusting the phase of the index signal as shown in FIG. 5(d), the phase difference is detected between the pulses of the index signal and the B position signal, respectively.
The phase differences t1 to t9 are stored in the memory 28. The phase difference can be detected by using a clock pulse synchronized with a horizontal synchronizing signal (HD), starting detection with an index signal pulse, and ending detection with a B position signal pulse. Further, the correction data is read out from the memory 28 in synchronization with the index signal, and this correction data is supplied to the serial-parallel conversion circuit 29 and read out as a parallel signal at a timing corresponding to the correction data.

Next, a method of creating a deflection waveform will be explained using the waveform diagram of FIG. 6. A horizontal synchronization signal is input to input terminal 8,
The signal is supplied to the continuous waveform generating circuit 36 as shown in FIG.
The horizontal sawtooth waveform shown in a) is created and added to the adder circuit 37.
supplied to On the other hand, the correction data shown in FIG. 6(b) from the storage circuit 28 in which color unevenness correction data is stored is supplied to the discontinuous waveform adjudication circuit 35, and the correction data is subjected to first-order differential processing, as shown in FIG. (The modulation signal for scanning speed modulation shown in Cl is output. This modulation signal is ON-
The signal is supplied to an adder circuit 37 through a switching circuit 38 for performing OFF control. The addition circuit 37 receives the sawtooth waveform signal from the continuous waveform generation circuit 36 shown in FIG.
The modulation signal from the switching circuit 38 shown in FIG. 6 (fc) is added to output a discontinuous deflection waveform signal shown in FIG. 6 (dl). As a result, a signal with a continuous deflection waveform as shown in FIG. By supplying signals to the horizontal deflection electrodes 3 of the image screen 1, a modulation of the scanning speed at points corresponding to the positions of the respective color phosphors on the phosphor screen is carried out. In the second half of the rise of bl, the scanning speed of the beam becomes faster, so the amount of light emitted at the corresponding point on the screen is kept small.

Furthermore, since the light is delayed during the falling period, the amount of light emitted at the corresponding point on the screen increases rapidly. Furthermore, as a means of the discontinuous waveform creation circuit 35, by performing first-order differentiation,
Since the average value of the modulation signal does not change at all, even when it is added to a continuous deflection waveform, there is no change in the amplitude of the deflection waveform or the DC component, so a stable deflection operation can be performed.

In the end, the amount of light emitted by the phosphor position in the horizontal direction of the screen is shown in Figure 6 (
e) The solid line eG2 shows the case of continuous scanning, and the broken line eG1 shows the case of partial scanning speed modulation, which improves the horizontal spot characteristics especially at high brightness and high frequency range. I can do it.

Next, the reason why brightness unevenness and color unevenness can be reduced by realizing a response as indicated by the broken line eG1 in FIG. 6(e) will be explained in detail. In the solid line in FIG. 6(e), the spot diameter is large and the signal is incident on the adjacent phosphors B and R, so the color is not monochromatic green (G) and the color purity is lowered, resulting in uneven division. Furthermore, since the aperture ratio of the G phosphor is low, the brightness is low, and even if a small change in the signal phase occurs, the aperture ratio changes, resulting in uneven brightness. The broken line +el in Figure 6 shows the case when discontinuous scanning is performed, and the scanning speed is modulated to slow down the scanning speed at the G phosphor position to improve the spot characteristics.
Since there is no incidence on adjacent phosphors and the aperture ratio of the G phosphor is high, uneven division does not occur. Factors that cause the spot diameter to deteriorate during continuous scanning include changes in the deflection position and limitation of the video signal band.

Next, a structure for stabilizing changes in the screen phase and amplitude due to fluctuations in the deflection system or high voltage fluctuations in the image display state will be described using the block diagram in FIG. 7 and the operational waveform diagram in FIG. 8.

The index signal from the index area 39 provided outside the display area 15 of the image screen 1 is supplied to the color unevenness correction signal generation circuit 27, and correction data is output by measuring the phase of the index signal and the B position signal. Ru. The correction data from the color unevenness correction signal generation circuit 27 is supplied to a storage circuit 28, where the data is stored. Data is read out from the storage circuit 28 by a correction data readout circuit 38 in synchronization with an index signal from the position detection circuit 33. That is, even during image projection, the signal from the index area 39 provided outside the display area 16 is constantly detected, and correction data is read out in synchronization with this index signal, thereby eliminating fluctuations in the deflection and high voltage systems. Even if the screen phase or amplitude varies due to the above, it is possible to always stably input signals to each color phosphor on the phosphor screen. Furthermore, even when performing discontinuous scanning, the input signal to the discontinuous waveform generation circuit 35 is generated by the signal from the correction data readout circuit 38 that is read out in synchronization with the index signal, so it is linear. Since there is no fear that the timing of each color signal of the parallel signal applied to the cathode and the modulation signal from the discontinuous waveform generation circuit 35 will deviate, stable image display without division unevenness can be performed.

Next, a method of switching between continuous scanning waveform and non-continuous scanning waveform will be explained. When creating the color unevenness correction signal in the color unevenness correction signal generation circuit 27 described above, it is necessary to measure the phase of the index signal from the index area and the B position signal from the display area 15 in each image display area. , measurements under continuous deflection conditions are required. Therefore, only when creating a color unevenness correction signal, a sawtooth wave with a continuous scanning waveform is generated as shown in FIG. 6th waveform
The deflection circuit 31 is switched so as to generate a staircase waveform of a discontinuous scanning waveform to which the modulation signal shown in FIG. 3(C) is added.

Note that this switching can be realized by controlling a switching circuit 38 shown in FIG. 4 that turns on and off the signal from the discontinuous waveform generating circuit 35.

As described above, continuous scanning is performed during the initial adjustment color unevenness correction signal, discontinuous scanning is performed during image projection, and the deflection speed of only each phosphor position within that area is modulated. As a result, the aperture ratio of each phosphor is always stable, especially with respect to fluctuations in the signal phase, so uneven brightness does not occur, and deterioration of spot characteristics in the horizontal direction is reduced, resulting in clear color purity and uneven division. Faithful image display is performed without any distortion. In addition, by reading out color unevenness correction data in synchronization with the index signal from the index area and creating a discontinuous scanning waveform using this data, stable images can be obtained even when screen phase and amplitude fluctuations occur. Display is performed.

Next, an image display device according to a second embodiment of the present invention will be explained using FIGS. 8 and 9. The difference from the first embodiment is that waveform processing is performed so that the scanning speed stop period of discontinuous scanning is wider than the parallel signal application period in order to further reduce division unevenness. It is.

In FIG. 8, components similar to those in the first embodiment are designated by the same reference numerals and detailed explanation thereof will be omitted. In FIG. 8, 40 is a color switching circuit for changing the color of data from the correction data reading circuit 38, and 41 is a color switching circuit for performing waveform shaping such as phase and pulse width of data from the correction data reading circuit 38. The waveform shaping circuit 42 is a first-order differentiation circuit that performs first-order differentiation to create a modulated waveform. The data from the color unevenness correction signal generation circuit 27 and the address signal which is an index signal are supplied to the storage circuit 28 and the correction data reading circuit 38, and the correction data is read out in synchronization with the index signal shown in FIG. 9 Tal. issued. In reality, the response of the display area 16 is in a state where the pulse response is degraded as shown in FIG. 9(b) depending on the spot diameter, the band of the amplifier circuit, etc. Note that FIG. 9 shows each operation waveform at a position corresponding to the position on the phosphor screen shown in (Cl).

The correction data from the correction data reading circuit 38 is supplied to the discontinuous waveform creation circuit 35. The discontinuous waveform creation circuit 35 includes a waveform shaping circuit 41 for performing waveform processing and a first-order differentiation circuit 42 for performing first-order differentiation.

First, the operation in the case where waveform shaping processing is not performed will be described below. The correction data shown in FIG. 9(al) is supplied to the first-order differentiation circuit 42, and the first-order differentiated signal shown in FIG. 9(d) is obtained. The deflection waveform shown in FIG. 9 (tel) is applied to the horizontal deflection electrode.However, by performing first-order differentiation processing in the first-order differentiation circuit 42, the data in FIG. 9(a) and FIG. 9(1e) Since a phase error t23 occurs between the deflection waveforms in FIG.
This means that the phase relationship between this and the stop period t21 of the deflection waveform shown in FIG. 9(e) is shifted, and therefore, it is not possible to reduce unevenness in division by superimposing the modulation waveform.

Therefore, in order to enlarge this phase error and stop period, the waveform shaping circuit 41 performs waveform shaping to reduce division unevenness. FIG. 9 fa from the correction data reading circuit 38
) is supplied to the waveform shaping circuit 41,
As shown in FIG. 9 +fl, the phase t20 is shifted in the direction of delay, and this shifted data generates the sawtooth wave shown in FIG. 9 (gl). The sawtooth wave is supplied to a first-order differentiating circuit 42. This first-order differentiating circuit 42 performs first-order differentiation of the data signal using, for example, reflection from a delay circuit, and differentiates the data signal corresponding to each color phosphor position shown in FIG. 9 (hl). A first-order differentiated correction signal is created.
The first-order differential signal shown in FIG. 9(h) is added to a common horizontal sawtooth wave, and the deflection waveform shown in FIG. After that, by performing first-order differentiation processing in the first-order differentiation circuit 42, there is no phase error between the data in FIG. 9(a) and the deflection waveform in FIG. 9(i), and The scanning speed is performed at a position corresponding to each color of phosphor shown in FIG.
Since the stop period t22 of the deflection waveform shown in FIG. 9 (it) can be set wider than the application period of lr, even when the signal phase changes or the screen amplitude/phase changes, the deflection waveform If it exists within the stop period t22 of By being able to realize this, it is possible to further reduce unevenness in division.

From the above, stopping the deflection speed during period t22 on the R phosphor as shown in FIG. 9(i) means that the signal phase is t31 at the position on the phosphor screen shown in FIG. If a signal position exists between t32 and t32, it will be projected on the R phosphor during period t22.In other words, even if a phase change occurs in the signal by stopping the deflection speed, the change in aperture ratio will The resulting brightness changes can be significantly reduced.As described above, by modulating the deflection speed only at each phosphor position within the image display area, spot characteristics can be improved, and by stopping the deflection speed, the signal can be improved. It is possible to have a correction margin for phase changes, and high brightness can be achieved.

As described above, waveform shaping is performed so that the scanning speed stop period of discontinuous scanning is wider than the application period of the parallel signal, and a discontinuous waveform is created to perform scanning speed modulation at each color phosphor position. As a result, the deterioration of the spot characteristics, especially in the horizontal direction, is significantly reduced, and a faithful image display that is clear, has good color purity, and is free from division unevenness is performed. In addition, by stopping the deflection speed only at each phosphor position, it is possible to have margin for correcting division unevenness at high brightness, and stable scanning speed modulation is possible even against various fluctuations and drifts. It is possible to further reduce unevenness in division.

10 to 12 show a third embodiment of the present invention. The difference from the first embodiment is that in order to create various deflection waveforms, a modulation waveform is created from the color signal corresponding to the position of each phosphor on the basic deflection waveform, and the modulation waveform is superimposed on the basic waveform. The point is that an arbitrary deflection waveform can be generated.

Note that in FIG. 10, components that perform the same operations as those in the first embodiment are given the same reference numerals, and explanations thereof will be omitted. In FIG. 10, 52 is a basic waveform generation circuit for generating a basic waveform such as a sawtooth waveform of a deflection waveform, 51 is an input terminal to which a color signal corresponding to each phosphor position on the image screen 1 is input, and 54 is a basic waveform generation circuit for generating a basic waveform such as a sawtooth waveform of a deflection waveform. 53 is an address generation circuit for generating an address corresponding to the color signal applied to the input terminal 51; 55 is a modulation waveform generation circuit for generating various modulation waveforms based on the address signal from the address generation circuit 54; 5 is a superimposition circuit for superimposing the modulation waveform from the modulation waveform generation circuit 55 on the fundamental waveform from the basic waveform generation circuit 52;
6 is a horizontal deflection output circuit for amplifying the deflection waveform from the superimposing circuit 53.

Next, regarding the image display device of this embodiment, FIG.
The operation will be explained using the operation waveform diagram shown in FIG.

First, a case will be described in which the scanning speed is stopped for each color signal. A horizontal synchronization signal is input to input terminal 8,
The signal is supplied to the basic waveform generation circuit 52 to create the horizontal sawtooth waveform shown in FIG.
3. On the other hand, the 11th
The color signal shown in FIG. 11(b) is supplied to an address generation circuit 54 to generate an address corresponding to the color signal shown in FIG. 11 fcl.

The address signal from the address generation circuit 54 is supplied to a modulation waveform generation circuit 55, and various modulation waveforms are generated at timings corresponding to the address signal. The modulation waveform generation circuit 55 is composed of a ROM in which data is written in advance. For example, from the modulation waveform generation circuit 55, as shown in FIG.
A modulated waveform as shown in FIG.
The horizontal deflection waveform shown in Fig. The modulation waveform shown in Fig. 11 (fl) is output, and by superimposing it on the basic waveform, the modulation waveform shown in Fig. 11 (hl
The horizontal deflection waveform shown in can be created.

Next, a case will be described in which modulation is performed in different scanning directions in each color signal period or trio period. Similarly to FIG. 11, the color signal shown in FIG. 12 (al) is supplied to an address generation circuit 54, which generates an address corresponding to the color signal. Various modulation waveforms are generated at timings corresponding to the signals.The modulation waveform generation circuit 55 outputs modulation waveforms with different scanning directions in the color signal period, as shown in FIG. ) superimposition circuit 53 on the basic waveform shown in
By superimposing the modulated waveform in , the horizontal deflection waveform shown in FIG. 12 (Cl) can be created from the superimposition circuit 53.
As shown in Figure +dl, scanning in which the scanning direction differs for each color phosphor period can be realized. Further, the modulation waveform generation circuit 55 outputs a modulation waveform with different scanning directions in a trio period as shown in FIG. 12, for example, and the modulation waveform is superimposed on the basic waveform shown in FIG. As a result, the horizontal deflection waveform shown in FIG. 12 (fl) can be created from the superimposition circuit 53. The scanning state corresponding to the fluorescent screen at the time of this horizontal deflection waveform is as shown in FIG. 12 (■■■).
Scanning with different scanning directions for each trio period can be realized.

As mentioned above, the basic waveform and modulation waveform are generated independently,
By creating horizontal deflection waveforms using these two different signal sources, various waveforms can be created. Further, by performing ON/OFF control of the modulated waveform, it becomes possible to switch and deflect the deflection waveform on which the fundamental waveform and the modulated waveform are superimposed. That is, a continuous fundamental deflection waveform,
Scanning can be performed by switching discontinuous deflection waveforms that can be set arbitrarily.

As described above, by creating a modulation signal to modulate the scanning speed at a position corresponding to the application timing of each color signal and adding this modulation waveform to the deflection waveform, it is possible to create a continuous deflection waveform and a discontinuous deflection waveform. Deflection waveform switching and arbitrary waveform generation can be easily realized.

13 and 14 show a fourth embodiment of the invention. The difference between this embodiment and the first embodiment is that in order to create various deflection waveforms, data is selected according to the application timing of the video signal by reading from a memory circuit in which deflection waveforms are written in advance. By converting the selected data into analog quantities, a continuous deflection waveform and a discontinuous deflection waveform are generated. In FIG. 13, components that perform the same operations as those in the first and third embodiments are designated by the same reference numerals, and their explanations will be omitted. In FIG. 13, 57 is an address creation circuit for creating an address signal corresponding to the synchronization signal applied to the input terminal 8, and 58 is a basic waveform for generating a basic waveform such as a sawtooth waveform of a deflection waveform. 1 is a data selection circuit for selecting correction data from the memory, and 60 is a digital-to-analog converter (D/A) for converting a digital quantity into an analog quantity.
), 61 is a data selection signal creation circuit for creating a data selection signal corresponding to the color signal applied to the input terminal 51.

Next, the image display device of this embodiment will be explained using the operating waveform diagram of FIG. 13. A horizontal synchronizing signal +bl is applied to the input terminal 8, and is supplied to the address signal generation circuit 57 to generate an n-bit address signal (Cl).
Cl is a memory 58 in which basic waveform data is written in advance.
supplied to A color signal (dl) is applied to the input terminal 51, and is supplied to the data selection signal creation circuit 61 to create the data selection signal tel.The data selection circuit 59 receives the basic waveform data from the memory 58 and the data selection signal. A selection signal tel is supplied from the control circuit 61, data in the address period of the selection signal is selected, and the data is selected so that the deflection speed stops during the ON period of the color signal fdl.Data selection circuit 59 The correction data from D/
A 60 is applied to convert the digital quantity into an analog quantity. Therefore, from D/A 60, when data selection is not performed, for example, a horizontal sawtooth wave (when al is data selection signal (e) and data selection is performed, color signal + hl
A staircase wave synchronized with the application timing of is output. Also, when a color signal with a different color signal period (fl is applied),
By performing the same operation as described above, the data selection signal generation circuit 61 outputs a selection signal {(a), and this signal is supplied to the data selection circuit 59 to perform data selection.
The D/A 60 outputs a staircase wave (it). In this way, a continuous sawtooth wave and a discontinuous staircase wave are obtained with the application timing of the color signal synchronized. The signal from the D/A 60 is a horizontally polarized The signal is supplied to the output circuit 56, amplified, and then applied to the horizontal deflection electrode 3.

As described above, by reading out the deflection waveform from the memory circuit in advance, selecting data in accordance with the application timing of the video signal, and converting the selected data into analog quantities, continuous It is easy to switch between a regular deflection waveform and a discontinuous deflection waveform, and to generate arbitrary waveforms.

In the first and second embodiments, the image display device uses a flat cathode ray tube in which a plurality of image display areas and phosphors of the three primary colors of red, green, and blue are sequentially arranged. Other image display devices may also be used.

Further, in the first to third embodiments, the case where the modulation signal superimposition means adds to a sawtooth wave which is a common horizontal deflection waveform has been described, but the superposition may be performed using an auxiliary deflection electrode.

Further, in the first to fourth embodiments, the continuous deflection waveform is a sawtooth wave and the discontinuous deflection waveform is a staircase wave, but other waveforms may be used.

Further, in the first embodiment, the case where the index area is provided at the top of the screen has been described, but it may be placed at any position as long as it is not affected by the image display area.

In addition, in the first and second embodiments, the correction signal is created using a first-order differential waveform or a sawtooth waveform synchronized with the parallel signal period. You may do so.

Furthermore, in the third embodiment, a case has been described in which the scanning direction is a deflection waveform generation for performing alternate scanning in the period of each color phosphor in a band block or in one triblet period. Alternate scanning may be performed.

Effects of the Invention As explained above, according to the present invention, it is possible to reduce the deterioration of the spot characteristics, especially in the horizontal direction, to display an image that is clear, has good color purity, and does not cause division unevenness, and also allows index signals to be By reading out the color unevenness correction data in synchronization, stable color unevenness correction can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an image display device according to a first embodiment of the present invention, FIG. 2 is an operational waveform diagram of a signal processing system in the same device, and FIG. 3 is an operational waveform diagram of a deflection system in the same device.
Figure 4 is a block diagram of the color unevenness correction signal generation circuit and deflection circuit in the device, Figure 5 is an operating waveform diagram of the correction signal generation circuit, Figure 6 is an operation waveform diagram of the deflection circuit, and Figure 7 is FIG. 8 is a block diagram of the image display device according to the second embodiment of the present invention, FIG. 9 is an operational waveform diagram of the same device, and FIG. 10 is a block diagram of the correction data reading means. A block diagram of an image display device in an embodiment of
1 and 12 are operational waveform diagrams of the same device, FIG. 13 is a block diagram of the image display device according to the fourth embodiment of the present invention, FIG. 14 is an operational waveform diagram of the same device, and FIG. 15 is a conventional diagram. FIG. 16 is a block diagram of a signal processing system of a conventional image display device; FIG. 17 is a block diagram of a conventional color unevenness correction circuit; FIG. 18 is a sectional view showing the structure of the phosphor screen of the image display device. 1... Image screen, 16... Display area, 17.39... Index area, 27
...Color unevenness correction signal creation circuit, 28...
- Memory circuit, 29... Serial-parallel conversion circuit, 3... Deflection electrode, 5... Linear cathode, 31... Deflection circuit, 35...・・・・・・
Discontinuous waveform adjudication circuit, 36... Continuous waveform creation circuit, 38... Switching circuit, 37... Addition circuit, 38... Correction data reading circuit, 41
......Waveform shaping circuit, 61...Modulation waveform creation circuit, 57...゜Address creation circuit, 58
... Memory, 59 ... Data selection circuit, 61 ... Data selection signal generation circuit.

Claims (1)

[Claims] It has a cathode that emits an electron beam, a deflection means that deflects the electron beam from the cathode according to a deflection signal, and a plurality of image display areas, and each image display area is provided with an index phosphor. An image display device comprising an image display element that forms an image by impinging an electron beam on a phosphor, the image display device detecting light from the index phosphor in the index area and light from the phosphor in the image display area. a color unevenness correction signal creation means for creating a correction signal for color unevenness correction; a conversion means for serial-to-parallel converting the input video signal according to the correction signal and supplying it to the cathode; An image display device comprising: a deflection circuit that generates a discontinuous signal that modulates the scanning speed of a body part, superimposes it on a deflection signal, and supplies the signal to the deflection means.