JPH03201790A - Adjustment method for picture display device - Google Patents

Abstract

PURPOSE:To easily adjust horizontal vertical deflection voltages by obtaining brightness gravity center of each beam spot of a picture data of a small divided periods, calculating a mean value of the brightness gravity center of several beam spots of a same scanning line, defining each scanning line position and deciding the vertical deflection voltage so as to decrease a change in the brightness between scanning lines. CONSTITUTION:Brightness of each line is measured by using a television camera 53 picking up the entire pattern and a horizontal deflection voltage at that time is stored, The horizontal deflection voltage maximizing the brightness is obtained and the color of each maximum point is discriminated from the difference of the brightness of R,G,B to recognize the horizontal deflection voltage to radiate each color fluorescent substance accurately. Then a camera 51 able to be moved vertically and horizontally is approached to divide the pattern in vertical and horizontal directions and the brightness gravity center of each beam spot of the picture data of a small section is obtained and the mean value of the brightness gravity center of several beam spots on a same scanning line is calculated to define each scanning line position and the vertical deflection voltage is decided to reduce the change in the brightness between scanning lines. Thus, the horizontal and vertical deflection voltages are adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention divides a screen on a screen vertically into a plurality of sections, and an electron beam generated from a line cathode provided in each vertical section is This invention relates to a method for adjusting an image display device in which an image is formed by many beam spots formed on a screen by irradiating a phosphor coated on the screen after being deflected in the vertical and horizontal directions. .

2. Description of the Related Art First, a basic configuration of an image display element used here will be explained with reference to FIG.

This display element includes, in order from the back to the front, a back electrode 1, a line cathode 2 as a beam source, and a beam extraction electrode 3.
, beam flow control electrode 4, focusing electrode 5, horizontal deflection electrode 6,
A vertical deflection electrode 7 and a screen plate 8 are arranged, and these are housed inside a flat vacuum container (not shown).

The line cathode 2 as a beam source is stretched in the horizontal direction so as to generate an electron beam distributed linearly in the horizontal direction, and a plurality of line cathodes 2 are arranged vertically at appropriate intervals. In the following, only seven wires (2A to 2G are shown) are provided. In this example, the spacing of the line cathodes is 3 m, and the number of line cathodes is 30.
27. The distance between the line cathodes 2 is not allowed to be increased freely, but is regulated by the distance between the vertical deflection electrode 7 and the screen 8, which will be described later. These wire cathodes 2 are constructed by coating the surface of a tungsten wire with a diameter of 10 to 30 um, for example, with an oxide cathode material. Then, as will be described later, the electron beams are controlled to be emitted sequentially from the upper line cathode 2a for a fixed period of time. The back electrode 1 is a line cathode 2 which is controlled to emit an electron beam for a certain period of time.
suppressing the generation of electron beams from other line cathodes 2,
It also functions to push out the generated electron beam only in the forward direction. This back electrode 1 may be constructed using the inner surface of the rear wall of the vacuum container.

The beam extraction electrode 3 is a conductive plate 11 having a large number of through holes 10 arranged at predetermined intervals in the horizontal direction facing each of the line cathodes 2a to 27, and conducts the electron beam emitted from the line cathode 2. It is taken out through the through hole 10.

Next, the control n-electrode 4 is connected to a vertically long conductive plate 1 having through holes 14 at positions facing each of the line cathodes 2a to 27.
5, and a plurality of them are arranged in parallel in the horizontal direction at predetermined intervals. In this embodiment, 120 conductive plates 15a to 15n for control electrodes are provided (only 8 are shown in the figure). This control electrode 4 controls the amount of passage of each of the electron beams divided horizontally by the beam extraction electrode 3 in accordance with a video signal for displaying each picture element. The 120 control electrodes 4 include 1
Video for each line is displayed at once.

The focusing electrode 5 is a conductive plate 17 having a through hole 16 at a position facing each through hole 14 provided in the control electrode 4,
The electron beam passing through the through hole 14 provided in the control electrode 4 is focused.

The horizontal deflection electrodes 6 include a plurality of conductive plates 18.1 arranged vertically on both sides of the through hole 16.
A voltage for horizontal deflection is applied to each electrode 18.18', and the electron beam of each picture element is deflected in the horizontal direction.
The G and B phosphors are sequentially irradiated to emit light. The deflection range is 2 for each electron beam in this example.
It is the width of a picture element.

The vertical deflection electrodes 7 include a plurality of conductive plates 19.1 arranged horizontally at intermediate positions between the through holes 16.
Consists of 9°, each conductive plate 19.19°
A vertical deflection voltage is applied to deflect the electron beam in the vertical direction. In this embodiment, a pair of conductive plates 19, 19'
The electron beam generated from one line cathode is vertically deflected to eight line positions. The 31 vertical deflection electrodes 7 constitute 30 pairs of conductors corresponding to each of the 30 line cathodes 2, resulting in a screen 8.
The electron beam is deflected so as to draw 240 horizontal lines upward.

The electron beam is mainly bent in the space between the horizontal and vertical deflection electrodes 6.7 and the screen 8, but the entire screen is deflected with a sufficiently small amount compared to the distance in this space so that large deflection distortion does not occur. The screen is split to allow for configuration.

The screen 8 is constructed by coating the back surface of a glass plate 21 with a phosphor 20 that emits light when irradiated with an electron beam, and adding a metal back layer (not shown) if necessary. The phosphors 20 are provided with two pairs of phosphors of three colors R, G, and 13 for each slit 14 of the control electrode 4, that is, for each horizontally divided electron beam. It is applied in vertical stripes.

The broken lines drawn on the screen 8 in FIG. 5 indicate vertical divisions displayed corresponding to each of the plurality of line cathodes 2, and the two-dot chain lines correspond to each of the plurality of control electrodes 4. Indicates the horizontal division that will be displayed. As shown in the enlarged view in Fig. 7, one section partitioned by these two has two R, G, and B phosphors for two picture elements in the horizontal direction.
0, and has a width of 8 lines in the vertical direction.

For example, the size of one section is IMn in the horizontal direction.

The vertical direction is 3wn. The phosphors of the three colors R, G, and B may be applied in an arrangement other than a vertical strip, for example, a delta arrangement.

Note that in FIG. 7, the length in the horizontal direction is drawn to be approximately twice as long as the length in the vertical direction for clarity.

Further, in this embodiment, one control electrode 4, that is, one
Two pairs of R, G, and B phosphors 20 are provided for two picture elements for the electron beam of the book, but of course, one picture element or three or more picture elements may be provided, and in that case, R, G, and B video signals for one picture element or three or more picture elements are sequentially applied to the control electrode 4, and horizontal deflection is performed in synchronization with this. Furthermore, the R, G, and B color phosphors may be applied in an arrangement other than vertical stripes, such as a delta arrangement, in which case horizontal and vertical deflection voltages suitable for the phosphor arrangement may be applied. Apply.

Next, the basic configuration of a drive circuit for displaying an image on this display element will be described with reference to FIG. 6. First, a driving portion for irradiating the screen 8 with an electron beam to emit raster light will be described.

The power supply circuit 22 is a circuit for applying a predetermined bias voltage (operating voltage) to each electrode of the display element, including Vl to the back electrode l, v3 to the beam extraction electrode 3, and ■ to the focusing electrode 5.
5. Apply a DC voltage of V8 to the screen 8.

The line cathode drive circuit 26 uses the vertical synchronization signal V and the horizontal synchronization signal H to create line cathode drive pulses (I-MA). Figure 8 shows the relationship between the vertical synchronizing signal (■), the horizontal synchronizing signal H, and the line cathode drive pulses (I-MA). is heated by flowing, and the heated state is maintained so that electrons can be emitted during the low potential period of the drive pulse (I to M). As a result, electrons are emitted from the 30 line cathodes 2i to 27 only during BHwi to which a low potential drive pulse (i to ma) is applied to each cathode. During the period when a high potential is applied, the potential applied to the line cathodes 2-27 is higher than the potential at the position of the line cathode 2 determined by the bias voltage applied to the back electrode 1 and the beam extraction electrode 3. Since the higher potential is positive, no electrons are emitted from the line cathodes 2a-27. Thus, in the line cathode 2, electrons are sequentially emitted from the upper line cathode 2a toward the lower line cathode 27 for each 8H period during the effective vertical scanning period.

The deflection voltage waveform generation circuit 40 includes a direct memory access controller (hereinafter referred to as a DMA controller) 41, a memory for storing deflection voltage waveforms (hereinafter referred to as a deflection memory) 42, and a digital-to-analog converter (hereinafter referred to as a D/A converter) 43h, 43.
V and generates vertical deflection signals v, v'' and horizontal deflection signals r, h''.

In this embodiment, regarding the vertical deflection signal, 240H
There are two sets of memory address areas for storing vertical deflection signals corresponding to each line of 8 minutes, and regular data is stored in the memory every 8 minutes.
A stepwise vertical deflection signal for two fields can be obtained. In addition, for the horizontal deflection signal, as described below, it is necessary to horizontally deflect the electron beam in six stages within one period, so six during IH and 240HX during one
There are memory address areas corresponding to 6/H = 1440 horizontal deflection waveforms, and by storing regular data in the memory every IH minute, a 6-step wave horizontal deflection signal can be obtained. .

As mentioned above, the line cathode 2
1 to which a low potential drive pulse is applied among A to 27
The electron beam emitted from the main line cathode is divided horizontally into 120 sections by the beam extraction electrode 3.
It is taken out as a row of 20 electron beams. As will be described later for each section, the amount of electron beam passing through the electron beam is suppressed by the mt control pole 4, and after being focused by the focusing electrode 5, a pair of horizontal deflection signals that change in six steps as shown in FIG. horizontal deflection electrode 18.18'
Therefore, R1, G1 of the screen 8 during each horizontal period
, B1, R2, G2, B2 (1 each of the limiting poles 5
The phosphors corresponding to 5a to 15h are R, G, and B for 2 pixels.
However, for convenience of explanation, one pixel is designated as R1, GI Bl, and the other is designated as R2, G2, B2).
/6 is irradiated.

Thus, in each line raster, horizontally 1
The electron beam for each of the 20 sections is R1, G1, B1, R.
The phosphors 20 of No. 2, G2, and B2 are sequentially irradiated. Therefore, for each horizontal section of each line, the electron beams are set to R1 and G1.
, B1. , R2, G2, and B2, a color image can be displayed on the screen 8.

Next, the modulation control portion of the electron beam will be explained. First, the R, G, and B primary color signals (hereinafter referred to as R, G, and B video signals) applied to the signal input terminals 23R, 123G, and 23B are sent to 120 sample-and-hold circuit sets, 31a
~31n. Each sample hold circuit &u3
1a to 31n are for R1, GI, Bl, and R2, respectively.
It has six sample and hold circuits for 1, G2, and B2. The sampling pulse generation circuit 34 generates signals for R1, G1, Bl, and R of the 120 sample and hold circuits m31a to 31n during an effective horizontal scanning period (approximately 50μ5ec) of the horizontal period (63.5μ5ec).
Corresponds to sample hold circuits for 2, G2, and B2. 120X6=720 sampling pulses Rat
~Bn2 are generated sequentially. Six of these 720 sampling pulses Ral to Bn2 are applied to each of the 120 #Jl sample and hold circuits u31a to 31n, and thereby each sample and hold circuit group 31a to 31n
When one line is divided into 120 groups, the video signals of R1, G1, B1, R2, G2, and B2 for each two picture elements are individually sampled and held. R1, G1, B of 1201Jl that sample and hold
The video signals of 1, R2, G2, and B2 are stored in 120 sets of memos '732a to 32n after completing the sample hold for one line.
The signals ◆ are transferred all at once by the transfer pulse t, and are held here for the next horizontal period. This retained R1, G1
, Bl, R2, G2, and B2 are applied to 120 switching circuits 35a to 35n. The switching circuits 35a to 35n each have R1, G1, B1, and R.
2, G2, and B2, and a common output terminal that sequentially switches and outputs these input terminals. The switching circuits 35a to 35n are simultaneously controlled by switching pulses rLgl, bl, r2, B2, and B2 applied from the switching pulse generating circuit 36.

Switching pulses r1, gl, bl, r2, B2, B
2 divides each horizontal period into 6 and switches the switching circuits 35a to 35n by H/6, R1, G1, B1, R2.
.

The output of each switching circuit 35a to 35n is applied to 120 sets of pulse width varying (PWM) circuits 37a to 37n, where sampled and held R1, G1,
The B1, R2, G2, and B2 video signals are pulse width modulated according to their magnitudes and output. This pulse width modulation circuit 37a
The output of ~37n is sent to the 120 conductive plates 15a of the control electrode 4 of the display element as a control signal for modulating the electron beam.
~15n each separately.

What should be noted here is that the switching circuits 35a to 3
Switching the supply of video signals of R1, G1, Bl, R2, G2, B2 at 5n, and switching the horizontal deflection of irradiation of the electron beams R1, G1, B1, R2, G2, B2 to the phosphors by the horizontal deflection drive circuit 41. However, they are synchronously controlled so that both the tie and the order match completely. As a result, when the electron beam is irradiating the R1 phosphor, the irradiation amount of the electron beam is
Controlled by the video signal, Gl, Bl, R2, G2,
B2 is also controlled in the same way, and R1 and G1 of each picture element
, B1, R2, G2, B2 The light emission of each party light is controlled by the video signal of R1, Gl, Bl, R2, G2, B2 of the picture element, and each picture element follows the input video signal. It is displayed by emitting light. Such control is 1
This is done simultaneously for lines 120 & II (2 pixels each) to display an image of 240 pixels per line, and then for 240 lines sequentially from the upper line to display one image on the screen 8. It will be displayed.

The above-mentioned operations are repeated for each field of the human video signal, and as a result, a moving image is displayed on the screen 8 in the same manner as in a normal television receiver.

Note that the lock necessary for controlling this image display device is supplied from a pulse generating circuit 39 whose timing is controlled by a horizontal synchronizing signal H and a vertical synchronizing signal V.

Problems to be Solved by the Invention Unlike the shadow mask type image display device, it is necessary to accurately irradiate the R, G, and B phosphors on the screen with an electron beam, and therefore the horizontal deflection voltage of the electron beam is must be accurately adjusted for each image display element.

Further, the above-mentioned image display element can be considered to have a structure in which a plurality of image display units each having a negative line cathode are connected in the vertical direction. Therefore, vertical and horizontal deflection distortion occurs in each image display unit, and mechanical assembly errors also occur in each image display unit, so the relationship between the deflection voltage and the amount of electron beam deflection is Different for each display unit.

In addition, when the electron beam is vertically deflected, the shape of the electron beam is deformed differently at the upper and lower sides. Furthermore, the brightness peak position of the electron beam differs between the upper and lower portions.

For the above reasons, in order to obtain a raster with good uniformity using the above-mentioned image display element, that is, a raster in which the joints of each image display unit are not noticeable as a peculiar pattern, it is necessary to increase the horizontal deflection voltage of each electron beam. It is necessary to precisely adjust the vertical deflection voltage. Conventionally, by visual inspection,
Since each electron beam spot was adjusted,
Approximately one hour of adjustment time was required for each unit.

The present invention solves the above-mentioned problems and provides an adjustment method that can easily and accurately adjust the horizontal and vertical deflection voltages in such an image display element.

Means to solve the problem i! In order to solve the problem I, the adjustment method of the present invention
- It is equipped with a television camera attached to the Y table and the X-Y table, an A/D converter that converts the video signal of the television camera into a digital signal, a personal computer, and a controller that controls the deflection waveform of the image display device. .

Operation With this configuration, horizontal deflection waveforms and vertical deflection waveforms are created by the following procedure, and the adjustment is completed.

First, several types of voltages v1, V2,
... Vm is applied, the brightness of each line at each voltage is measured using a television camera that captures the entire screen, and the horizontal deflection voltage at that time is stored. By determining the horizontal deflection voltage at which the brightness becomes maximum, and determining the color of each maximum point from the difference in the brightness of R, C, and B, the horizontal deflection voltage is determined to accurately irradiate each color of phosphor. can be known.

By performing the above operations on the entire screen, an accurate horizontal deflection voltage waveform can be created.

Next, after applying the horizontal deflection voltage waveform obtained in the above operation, a vertically and horizontally movable camera is brought closer and the screen is divided vertically and horizontally, and the brightness of each beam spot of the image data of a small section is Find the center of gravity, calculate the average of the luminance centroids of several beam spots on the same scanning line, define the position of each scanning line, and determine the vertical deflection voltage so that there is little change in luminance between each scanning line. do.

By performing the above operations for the entire screen, an accurate vertical deflection voltage waveform can be created.

Example An embodiment of the present invention will be described with reference to FIG.

50 is an image display device to be adjusted having the above-described configuration; 51
53 is a first camera that can capture a small section of the screen of the image display device 50; 52 is an X-Y table that can accurately move the first camera 51 to any small section of the screen; A second camera 54 that can capture the entire screen is connected to a second camera 53 for adjusting the horizontal deflection voltage waveform.
The first camera 51 is switched to be used for vertical deflection voltage waveform adjustment. It is a camera changeover switch. 55 is an A/D converter that converts the video signals of the cameras 51 and 53 into digital signals. 56 is a personal computer. 57 is a controller that changes the deflection voltage.

For purposes of explanation, the horizontal deflection voltage of the image display device 50 is V
It is assumed that 256 types of voltage settings for O-V255 are possible. First, the controller 54 fixes the horizontal deflection voltage of the image display device 50 to vo. The second camera 53 is used to measure the screen output and captures the entire screen. In this state, a raster is drawn on the image display device, and the output of the second camera 53 for each scanning line is A/D converted and stored in the personal computer 56.

If the number of scanning lines is -240, the amount of data is 240, and the required time is 1/60 second. Next, the horizontal deflection voltage is fixed at vl and the same operation is repeated. The total amount of data is
240 x 255 pieces and the required time is 1/60 x 25
5=4.3 seconds.

Next, a method for creating horizontal deflection data based on 240 x 255 pieces of data will be explained using FIG. 2.

If the output is graphed with one scanning line fixed and the horizontal deflection voltage as a variable, it will look like the curve in FIG. 2.

Adjustments are made using a filter or the like so that the maximum values have different sizes depending on the R, G, and B colors.

fR, fG+, fB+, fRz, fGz,
rBz(7) A waveform in which horizontal deflection voltages each giving two maximum values are connected in a stepwise manner becomes the horizontal deflection voltage waveform necessary to draw the scanning line specified above.

Adjustment for waterside deflection is completed by similarly obtaining horizontal deflection voltage waveforms for all scanning lines.

Next, leave the determined waterside deflection voltage applied,
The camera changeover switch 54 is set to the first camera 51.

In order to obtain the required resolution, the first camera 51 is brought closer and a certain part of the screen is enlarged.

At this time, by using the X-Y table 52, it is possible to accurately move vertically and horizontally, and to measure a small section of any part of the screen.

Next, the third method of defining the scanning line position and creating vertical deflection data by determining the luminance center of gravity for a certain small section.
This will be explained using FIG.

First, image data of a small section in FIG. 3 is shown.

It includes five scanning lines, and each scanning line is data consisting of 13 beam spots. FIG. 4 is an enlarged view of a certain beam spot. The luminance center of gravity in this case is determined as follows.

m□10m! +...m□ (mig...brightness data of each sample) mi,
. . . Luminance data of each sample k . . . Maximum sample value l of the X coordinate. . . Maximum sample value of the Y coordinate.

The luminance centroid is determined for each beam spot, and the vertical position of the scanning line is defined as the average of the luminance centroids of the 13 beam spots. In this way, the scanning line position is determined, and the vertical deflection voltage is determined based on the position so that the change in brightness between each scanning line is small.

Adjustment for vertical deflection is completed by obtaining vertical deflection voltage waveforms for all scanning lines in the same manner.

Effects of the Invention As described above, according to the present invention, in order to create a deflection waveform by selecting the horizontal deflection voltage at which the electron beam irradiates the center of the striped phosphor for each scanning line, the horizontal deflection voltage is adjusted. This can be done automatically, quickly, and accurately. Furthermore, by determining the luminance center of gravity at that position for each scanning line, the vertical deflection voltage can be adjusted so that there is little change in luminance between each line based on that position. automatically and promptly,
and can be determined accurately.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a system conceptual diagram of an apparatus for realizing an image display element adjustment method in an embodiment of the present invention, and FIG.
3 and 4 are diagrams for explaining the vertical deflection voltage setting and operation of FIG. 1, and FIG. 5 is an exploded perspective view of the image display element. 6 is a block diagram showing the drive circuit of FIG. 5, FIG. 7 is an enlarged view of the screen, and FIG. 8 is a diagram of various voltage waveforms for explaining the operation of FIG. 5. 1... Back electrode, 2... Line cathode, 3...
...Beam extraction electrode, 4...Beam flow control electrode, 5...Focusing electrode, 6...Horizontal deflection electrode, 7...Vertical Deflection electrode, 8...
... Screen, 51.53 ... Camera, 52
......X-Y table, 55...A/D
Converter, 56...Personal computer, 5
7... Controller.

Claims (1)

[Claims] Divide the screen vertically into multiple sections,
After the electron beam generated from the line cathode provided in each vertical section is deflected in the vertical and horizontal directions,
In an image display device in which an image is formed by many beam spots formed on a screen by irradiating a phosphor coated on the screen, a means for changing a horizontal deflection voltage and a first camera are used. Means for detecting changes in brightness of the entire screen is provided, and the horizontal deflection voltage is determined by determining the relationship between the changes in brightness and the horizontal deflection voltage, and a second camera that can move in vertical and horizontal directions is provided. A second camera is brought close to the image display device, the screen is divided vertically and horizontally, the brightness center of gravity of each beam spot of the image data of the divided small sections is determined, and the brightness of several beam spots of the same scanning line is determined. A method for adjusting an image display device, comprising: calculating an average of the center of gravity, defining the position of each scanning line, and determining a vertical deflection voltage so that there is little change in brightness between each scanning line.