JPH0479488A - Adjusting method for horizontal focusing dispersion in vertical partition of image display device - Google Patents

Abstract

PURPOSE:To adjust horizontal focusing dispersion in the vertical partition of an image display device by detecting the horizontal focusing diameter of an electron beam in the vertical partition quantitatively, and setting the diameter of the beam when deflecting in an upper direction equal to that when deflecting in a lower direction by adjusting each electrode voltage. CONSTITUTION:A horizontal deflecting voltage is varied for the scanning line of each vertical partition of the image display device 1 at a constant interval, and luminance at that time is measured by a photodetector 3, and after the output of the photodetector 3 is amplified by an amplifier 4 and is A/D-converted, the luminance change of each scanning line is stored in memory 6. The data of the change is processed by a personal computer 7, and the dispersion of the horizontal focusing diameter in the vertical partition is made into a numerical value, and each electrode voltage is adjusted so as to minimize the numerical value. Therefore, the horizontal focusing diameted of the electron beam in the vertical partition can be detected quantitatively, and the horizontal focusing diameter of the electron beam when it is varied in the upper and lower directions can be set equally. Thereby, it is possible to adjust the horizontal focusing dispersion in the vertical partition of the image display device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an adjustment force method for horizontal focus variations within a vertical section of an image display device.

(Prior Art) The basic structure of a conventional image display element is shown in FIG. 5 and will be explained.

This display element includes, in order from the rear to the anode side, a back electrode 11, a line cathode 12 as a beam source, a beam extraction electrode 13, a beam current control electrode 1'@14, and a focusing electrode 15.
, horizontal deflection electrode 16, vertical deflection electrode 17, screen 1
8, etc. are arranged, and these are housed inside the vacuum container.

The line cathode 12 as a beam source is oriented horizontally so as to generate an electron beam distributed linearly in the horizontal direction. A plurality of wire cathodes 12 (only seven wire cathodes 12<b>1 to 12<b>g are shown in this description) are provided at intervals in the vertical direction. In this configuration, the spacing between the line cathodes is 3 mm, and the number of line cathodes 12 is 12i to 127, assuming that 30 line cathodes are provided. The interval between the line cathodes 12 cannot be freely increased, and the vertical deflection electrode 1 described later
7 and the screen 18. These wire cathodes 12 are constructed by coating the surface of a tungsten rod with a diameter of 10 to 30 μm with an oxide cathode material. As will be described later, the line cathodes 12 are controlled to sequentially emit electron beams from the upper line cathode 12a to the lower line cathode 127 for a fixed period of time.

The back electrode 11 has the function of suppressing the generation of electron beams from line cathodes other than the corresponding line cathode, as well as pushing the electron beams only toward the anode.

Although the vacuum container is not shown in FIG. 5, it is also possible to adopt a structure in which the back electrode 11 is used to integrate the back electrode 11 with the vacuum container. The beam extraction electrode 13 is a conductive plate 20 having a large number of through holes 19 arranged at regular intervals in the horizontal direction facing each of the line cathodes 12a to 127, and allows the electron beam emitted from the line cathodes 12 to be It is taken out through the through hole 19. Next, the beam flow control electrode 14 is connected to the line cathode 12
The conductive plates 22 are vertically long conductive plates 22 having through holes 21 at positions facing each of the conductive plates 127, and a plurality of conductive plates 22 are arranged in parallel in the horizontal direction at predetermined intervals. In this configuration, 120 conductive plates 22a to 22n for control electrodes are provided (only 8 are shown in FIG. 5). The beam flow control circuit 1'l14 controls the amount of passage of each of the electron beams divided horizontally by the beam extraction electrode 13, corresponding to the picture elements of the video signal and in synchronization with the timing of horizontal deflection, which will be described later. are doing. The focusing electrode 15 is
The electron beam is focused by a conductive plate 24 having a through hole 23 at a position facing each through hole 21 provided in the beam flow control electrode 14 .

The horizontal deflection electrodes 16 include a plurality of conductive plates 2 arranged vertically along both sides of the through hole 23 in the horizontal direction.
5.26, and a horizontal deflection voltage is applied to each conductive plate. The electron beams for each picture element are each deflected in the horizontal direction by 3-, and sequentially irradiate the R, G, and B phosphors on the screen 18 to emit light. In this configuration, each electron beam has two
It is deflected by a trio. The vertical deflection electrode 17 is connected to the through hole 2
The electron beam is composed of a plurality of conductive plates 27 and 28 arranged horizontally at intermediate positions in the vertical direction of each of the conductive plates 27 and 28, and a vertical deflection voltage is applied to deflect the electron beam in the vertical direction. In this configuration, the pair of conductive plates 27 and 28
The electron beam generated from the book line cathode is deflected by eight lines in the vertical direction. Thirty pairs of vertical deflection conductors corresponding to each of the 30 line cathodes are formed on the vertical deflection electrode 17, which is composed of 31 pieces, and the screen 18
240 horizontal scanning lines are drawn vertically on the top.

As explained above, in this configuration, the horizontal deflection electrode +6. A plurality of vertical deflection electrodes 17 are arranged in a comb shape. Further, by setting the distance to the screen 18 longer than the distance between the horizontal and vertical deflection electrodes, it becomes possible to irradiate the screen 18 with the electron beam with a small amount of deflection.

This allows the number of horizontal and vertical deflection electrodes to be reduced.

As shown in FIG. 5, the screen 18 is constructed by coating the back surface of a glass plate 29 with phosphor 30 in a striped pattern.

Although not shown, a metal back and carbon are also coated. The phosphor 30 is provided so as to irradiate two trios of R, G, and B phosphor pairs by horizontally deflecting an electron beam passing through one through hole 21 of the beam control electrode 14. It is applied in vertical stripes.

In FIG. 5, the dashed lines drawn on the screen 18 indicate the vertical divisions displayed corresponding to each of the plurality of line cathodes 12, and the two-dot chain lines correspond to each of the plurality of beam flow control electrodes 14. Indicates the horizontal division that will be displayed. FIG. 4 shows an enlarged view of one section partitioned by broken lines and two-dot chain lines. As shown in Fig. 4, in the horizontal direction, there are two trios of R and G.

The B phosphor has a width of 8 lines in the vertical direction. In this example, the size of one section is 1 mm in the horizontal direction and 3M in the vertical direction.

Although the phosphors of the three colors R, G, and B are shown in stripes in FIG. 4, they may be arranged in a delta pattern. However, when arranged in a delta shape, it is necessary to apply horizontal and vertical deflection waveforms that are compatible with the arrangement.

In FIG. 4, for convenience of explanation, the vertical and horizontal dimension ratios are different from the image displayed on the actual screen.

In addition, in this configuration, two trios of R, G, and B phosphors are provided for one through hole 21 of the beam flow control electrode 14, but it may be configured with one trio, three trios, or more. You can leave it there. However, the beam flow control electrode 14 has one
A trio or more than three trios of R, G, and B video signals are sequentially applied, and it is necessary to perform horizontal deflection in synchronization with this.

Next, the operation of the drive circuit for driving this display element is as follows.
This will be explained with reference to FIG. First, the driving portion that irradiates the screen 18 with an electron beam to display the image will be explained.

The power supply circuit 31 is a circuit for applying a predetermined bias voltage to each electrode of the display element, including Vl to the back electrode 11, V3 to the beam extraction electrode 13, V5 to the converging electrode 15,
A DC voltage of V8 is applied to the screen 18. The line cathode drive circuit 32 uses the vertical synchronization signal V and the horizontal synchronization signal H to create line cathode drive pulses (I-MA). FIG. 7 shows the timing diagram. As shown in FIG. 6 (I to M), each line cathode 12A to 127 is heated by a current flowing while the drive pulse is at a high potential.
The heated state is maintained such that electrons are emitted during periods when the potential is low. As a result, electrons are emitted from the 30 line cathodes 12a to 127 for eight horizontal scanning periods to which low potential drive pulses (i to ma) are applied, respectively. During the period when a high potential is applied, the back electrode 11 and the beam extraction electrode 13
The potential around the linear cathode 12 determined by the bias voltage applied to the linear cathode 12
Since the potential applied to 7 is higher, no electrons are emitted from the line cathode. To construct one screen, the potentials may be sequentially switched from the upper line cathode 12a to the lower line cathode 127 every 8 scanning periods.

Next, the deflection part will be explained. The deflection voltage generation circuit 33 is
Direct memory access controller (hereinafter referred to as DMA controller) 34. Deflection voltage waveform memory (
(hereinafter referred to as deflection memory) 35. It is composed of digital-to-analog converters (hereinafter referred to as D/A converters) 36h, 36v, etc., and outputs vertical deflection signals.

V' and a horizontal deflection signal, h'.

In this configuration, the vertical deflection signal is displayed for 240 horizontal scanning periods in an l field in consideration of overscanning. Further, the memory address area storing vertical deflection position information corresponding to each line is divided into a first field and a second field, each having one set of memory capacity. When displaying, data is read from the corresponding deflection memory 35, converted to an analog signal by the D/A converter 36v, and applied to the vertical deflection electrode 17.

The vertical deflection position information stored in the deflection memory 35 is composed of almost regular data every 8 horizontal scanning periods, and the D/A converted waveform is also a vertical deflection signal with approximately 8 levels. As mentioned above, it has a memory capacity for two fields, so that the position can be finely adjusted for each horizontal scanning line.

Regarding the horizontal deflection signal, it is necessary to horizontally deflect the electron beam in six stages during one horizontal scanning period, and a memory is provided so that the deflection position can be finely adjusted for each horizontal scanning. Therefore, assuming that 480 horizontal scanning periods are displayed between one frame, 480 x 6 = 2880 bytes of memory are required, but since the data of the first field and the second field are shared, the memory is actually 1440 bytes. is using memory. When displaying, the deflection information corresponding to each horizontal scanning line is read out from the deflection memory 35 and sent to the D/A.
The signal is converted into an analog signal by a converter 36v and applied to the horizontal deflection electrode 16. To summarize, during the display period excluding the vertical retrace period of the vertical period, the electron beam emitted from one of the line cathodes 12a to 12ma to which a low-potential driving pulse is applied is a beam. It is horizontally divided into 120 sections by extraction electrodes 13, forming 120 electron beam rows. As will be described later, the amount of beam passing through the electron beam is controlled by a beam flow control electrode 14 for each section, and after being focused by a focusing electrode 15, a pair of electron beams that change in approximately six stages as shown in FIG. R1, Gl, Bl and R2, G2 . The phosphors such as B2 are sequentially irradiated for each horizontal display period/6.

Thus, each horizontal line raster directs the electron beam in each of the 120 sections to R1, Gl, Bl and R2, G2 .
, B2, a color image can be displayed on the screen 18.

Next, the modulation control portion of the electron beam will be explained. First, in Fig. 6, signal input terminals 37R937G, 37E
The R, G, and B video signals applied to the sample and hold circuits are applied to 120 sample-and-hold circuit sets 38a to 38n.

Each sample and hold circuit set 38a to 38n is connected to R
6 for 1, for GI, for BL and R2, for G2, for B2
It consists of several sample and hold circuits. The sampling pulse generation circuit 39 has a horizontal period (63.5 μs)
During the horizontal display period (approximately 50 μs), each of the 120 sample and hold circuits 38a to 38n for R1,
720 (120× 6 ) sampling pulses Ra corresponding to sample hold circuits for Gl, Bl, R2, G2, and B2
1 to Rn2 are generated sequentially. The 720 sampling pulses are applied to each of the 120 sample-and-hold circuit sets 38a to 38n, six pulses at a time, so that each sample-and-hold circuit set receives two pulses from each of the 120 sample-and-hold circuits. R1゜Gl, Bl for picture elements,
R2, G2. Each B2 video signal is individually sampled and held. 120 sample-held sets of R1, Gl, Bl, R2°G2. The B2 video signal is 19
120 sets of memory 4 after 42 minutes of sample hold
0a to 40n are transferred all at once by a transfer pulse t,
Here, it is held for the next l horizontal scanning period. The held signals are applied to 120 switching circuits 41a to 4In. Each of the switching circuits 41a to 41n is R
1.Gl.

Bl, R2, G2. It is composed of a circuit having individual input terminals of B2 and a common output terminal that sequentially switches and outputs them, and the switching pulses rl, gl, bl, r applied from the switching pulse generation circuit 42.
2. g2. Switching is controlled simultaneously by B2.

Switching pulses rl, gl, bl, r2°g2. B
2 divides each horizontal display period into 6 and divides each horizontal display period into 6 horizontal display periods/6
Switch the switching circuits 41a to 4In by R1,
Gl, Bl, R2, G2. Each B2 video signal is time-divided and sequentially output, and supplied to pulse width modulation circuits 43a to 43n.

The output of each switching circuit 41a to 41n is 120
A set of pulse width modulation (hereinafter referred to as PWM) circuits 43a to 4
3n, R1, Gl, Bl, R2, G2゜B2
The pulse width is modulated according to the magnitude of each video signal and output. The outputs of the pulse width modulation circuits 43a to 43n are used as control signals for modulating the electron beam to the 120 conductive plates 22a to 22n of the beam flow control electrode 14 of the display element.
are added to each separately.

Next, horizontal deflection and display timing will be explained. R1°Gl, B in switching circuits 41a to 41n
l, R2, G2. B2 video signal switching and DMA
Electron beams R1, Gl, Bl, by the controller 34
R2, G2. The timing and order of switching the horizontal deflection to the B2 phosphor are synchronously controlled so that they completely match. As a result, when the R1 phosphor is irradiated with the electron beam, the irradiation amount of the electron beam is controlled by the R1 control signal, and the following Gl, Bl, R2, G2 . B2 is also controlled in the same way, and R1°Gl, Bl of each picture element
, R2, G2. B2 The light emission of each phosphor is the R1 of that picture element,
Gl, Bl, R2, G2. Each picture element is controlled by the B2 video signal, and each picture element is displayed by emitting light according to the input video signal. Such control is executed for 120 sets (2 picture elements each) for 1 line for a period of time to display an image of 240 picture elements for 1 line, and is further carried out sequentially for 1 field of 240 lines starting from the upper line. An image is displayed on the screen 18.

Further, the above operations are repeated for each field of the input video signal, and a television signal or the like is displayed on the screen 18.

The basic clock necessary for this configuration is supplied from a pulse generation circuit 44 shown in FIG. 6, and the timing is controlled by a horizontal synchronizing signal H and a vertical synchronizing signal V.

(Problem to be Solved by the Invention) In the image display device as described above, by applying a different voltage to each electrode, the lever finally causes the phosphor to emit light on the screen to form a beam spot. , if each electrode voltage is not appropriate, the horizontal focus diameter of the electron beam in the vertical section will be different in two directions, and when it is deflected downward.

For the above reasons, in order to adjust the image display device, it is necessary to detect the horizontal focus diameter of the electron beam in the vertical section. Conventionally, the horizontal focus diameter was adjusted by visual inspection so that the horizontal focus diameter was the same when deflected upward and downward, so it was not possible to make a quantitative judgment.

An object of the present invention is to solve the above-mentioned drawbacks, and to quantitatively detect the horizontal focus diameter of an electron beam in a vertical section, and adjust the horizontal focus diameter when deflected upward or downward by adjusting each electrode voltage. An object of the present invention is to provide a method for adjusting horizontal focus variations within a vertical section of an image display device, which can be made equal in amount by the following methods.

(Means for Solving the Problems) The present invention provides a light receiving element capable of measuring the brightness of an image display element;
An amplifier that amplifies the output of the light receiving element, and an A/
It consists of an A/D converter that performs D conversion, a memory that stores digital data, a controller that controls the amount of deflection of the electron beam of the image display device, and a personal computer that processes data and controls the controller.

(Function) With the above configuration, the horizontal focus diameter of the electron beam in the vertical section can be quantitatively detected by the following procedure, and the horizontal focus diameter when deflected upward and downward can be made the same amount.

The horizontal deflection voltage is varied at regular intervals for the scanning lines of each vertical section of the image display device. The brightness at that time is measured by a light receiving element, and the output of the light receiving element is amplified by an amplifier and A/D converted, and then the change in brightness of each scanning line is stored in a memory. The data is processed by a personal computer, and the variation in horizontal focus diameter in vertical sections is quantified. Each electrode voltage is adjusted so that its value is the smallest.

(Example) An example of the present invention will be described with reference to FIGS. 1, 2, and 3.

FIG. 1 is a block diagram of a device that implements a method for adjusting horizontal focus variations in an image display device according to the present invention. In the figure, reference numeral 1 denotes an image display device for adjusting horizontal focus diameter variations in vertical sections, and has the configuration shown in FIG. 4. 2 is a controller that controls the amount of deflection of the electron beam of the image display device, 3 is a light receiving element that can measure the brightness of the image display device, 4 is an amplifier that amplifies the output of the light receiving element, and 5 is an A/D converter for the output of the amplifier. 6 is a memory for storing digital data. 7 is a personal computer that processes data and controls the controller, and 8 is a filter that allows only light of a certain wavelength to pass through.

FIG. 2 shows the relationship between beam position and brightness when the horizontal deflection voltage is changed at certain intervals for a scanning line with vertical divisions.

FIG. 3 shows the relationship between the vertical deflection voltage and WB representing the horizontal focus diameter for vertically divided electron beams.

The operation will be explained below.

For purposes of explanation, assume that the number of scanning lines in the vertical section of the image display device is two. First, the personal computer 7 controls the controller 2 to set the horizontal deflection voltage of the image display device l.
It is changed at constant intervals with a period of /60. At that time, the movement of the beam spot in the scanning line with vertical divisions will be as shown in Figure 2 (a), and the change in brightness obtained at the light receiving element 3 through the filter 8 will be as shown in Figure 2 (b). Become.

Focusing on the peak of this change in brightness, the steepness differs depending on the size of the horizontal focus diameter. Here, the maximum value PT and minimum value pH of the peak are determined by the personal computer 7.
, calculate P-(PT + PB)/2, and calculate the value of the bandwidth WB when the peak is sliced at the brightness of P. The size of the horizontal focus of each scanning line can be quantitatively detected by the value of WIl.

Next, as shown in Figure 3, the vertical deflection voltages α and β
By determining WB when , and calculating the slope = (WB(β)-WB(α))/β-α, it is possible to express the variation in the horizontal focus diameter of the electron beam in the vertical section. That is, if the value of K is made as small as possible by adjusting each electrode voltage, the horizontal focus diameter can be made the same amount when deflecting upward and downward.

(Effects of the Invention) According to the present invention, the horizontal focus diameter of the electron beam in the vertical section of the image display device is quantitatively detected, and
The horizontal focus diameter when deflected downward can be made the same amount by adjusting each electrode voltage, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a device that implements a method for adjusting horizontal focus variations in an image display device according to an embodiment of the present invention, FIGS. 2 and 3 are characteristic diagrams for explaining the same operation, and FIG. Enlarged view of the screen in the image display device, No. 5
The figure is an exploded perspective view of the image display device, FIG. 6 is a block diagram of the drive circuit of the device, and FIG. 7 is a waveform diagram for explaining the operation. l...Image display device, 2...Controller,
3... Light receiving element, 4... Amplifier, 5...
・A/D converter, 6...Memory, 7...Personal computer, 8...Filter patent applicant Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] A screen coated with a phosphor that emits light when irradiated with an electron beam, a line cathode that generates an electron beam in each vertical section of the screen above the screen, and an electron beam generated at the line cathode. separating means for separating the electron beam into each horizontal section and irradiating the screen onto the screen; a deflection electrode that deflects; and a beam flow control back electrode that controls the amount of emitted light from each pixel on the screen by controlling the amount of the electron beams separated into the horizontal sections irradiated onto the screen. , quantitatively detects the horizontal focus diameter of the electron beam in the vertical section of the image display device including an acceleration electrode that accelerates the electron beam to irradiate the electron beam to the screen, and determines the horizontal focus diameter when deflected upward and downward. A method for adjusting horizontal focus variation within a vertical section of an image display device, characterized in that the horizontal focus variation can be made the same amount by adjusting an electrode voltage.