JPH0740751B2 - Beam position deviation measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a beam position deviation measuring apparatus suitable for use in adjusting deflection and convergence of a television receiver.

[Outline of Invention]

The present invention, in a beam position deviation measuring device suitable for use in deflection and convergence adjustment of a television receiver, a plurality of sensors are opposed to a predetermined position on the tube surface,
By generating an inclination pattern for each position of each sensor and detecting the positional deviation of the beam from the output of each sensor, the positional deviation of the beam can be measured with high accuracy.

[Conventional technology]

Conventionally, deflection and convergence adjustment of a television receiver on a production line have been performed by projecting a predetermined dot pattern on the screen of the television receiver, capturing this dot pattern with a color camera, and storing the output of this color camera in memory. Then, from the output of this memory, red, green,
The position information of the electron beam was obtained by finding the center of each blue dot, and this was performed based on these position information.

[Problems to be solved by the invention]

However, in order to obtain the position information of each of the red, green, and blue beams from the image pickup output of the color camera stored in the memory in this way, a complicated calculation is required. In addition, when measuring with a color camera like this,
Since the measurement accuracy is determined by the sampling frequency of the color camera, there is a limit to improving the measurement accuracy. Furthermore,
A large number of color cameras are required to measure many measurement points at the same time, and a high-precision mechanism is required when absolute position measurement from the bezel is required such as deflection measurement. To do. Therefore, there is a problem that the device becomes large and expensive.

Therefore, an object of the present invention is to provide a beam position deviation measuring device that can measure a beam position with high accuracy and in a short time without using a color camera.

Another object of the present invention is to provide a beam position measuring device which is small in size and inexpensive.

[Means for solving problems]

According to the present invention, a plurality of sensors are arranged facing each other at a predetermined position on the surface of a color cathode ray tube, an inclination pattern is generated at each sensor position, and a beam of the color cathode ray tube from a reference position at each sensor position is generated. It is a beam position shift measuring device that detects a position shift.

[Action]

On the adjusted television receiver, a tilt pattern of a predetermined brightness change is projected corresponding to each sensor arranged at a predetermined position on the tube surface. The tilt pattern projected on the television receiver is received by the sensor arranged at a predetermined position on the tube surface.

The positional deviation of the beam is calculated from the detection output of this sensor.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall construction of an embodiment of the present invention. As shown in FIG. 1, the television receiver 1 to be adjusted is suitable for use as a display of a microcomputer, and is mounted on a mounting table 2 in which a computer 3 is incorporated and adjusted. When adjusting the deflection and convergence, as shown in FIG.
The pickup 4 is attached by an L-shaped attachment 5 at a predetermined position facing the fluorescent surface of the cathode ray tube of the television receiver 1.

As shown in FIG. 3, the pickup 4 has a predetermined number of photosensors, for example, 63 photodiodes S (1,1) to S (S).
(7,9) are arranged two-dimensionally. The outputs of these photodiodes S (1,1) to S (7,9) are amplifiers A (1,1) to A (7,9) and integrators I (1,1) to I
(7,9) are supplied respectively. Integrators I (1,1) to I (7,
The output of 9) is sequentially switched by the analog switches SW (1,1) to SW (7,9) and supplied to the A / D converter 11. Sensors S (1,1) to S by A / D converter 11
The output of (7,9) is digitized with 12 bits, for example. The output of the A / D converter 11 is output via the I / O port 12 and supplied to the computer 3. These amplifiers A (1,1) to A (7,9) and integrators I (1,1) to I (7,9)
9), the analog switches SW (1,1) to SW (7,9), and the A / D converter 11 are the circuit section 6 of the pickup 4 in FIG.
It is stored in.

The television receiver 1 to be adjusted is supplied with a tilt pattern having a predetermined brightness from the computer 3 corresponding to each sensor of the pickup 4. The projected patterns are photodiodes S (1,
The light is respectively received by 1) to S (7,9), and the outputs of the photodiodes S (1,1) to S (7,9) are sequentially supplied to the computer 6. The computer 6 calculates the position information of the electron beam from the outputs of the photodiodes S (1,1) to S (7,9).

The photodiodes S (1,1) to S (1,9) in the first row
After the output of is supplied to the computer 3, the output of the photodiodes S (5,1) to S (5,9) in the fifth row is supplied to the computer 3 with time. Similarly, there is a time margin between the photodiodes in the second row and the photodiodes in the sixth row and the photodiodes in the third row and the photodiodes in the seventh row with respect to data extraction. Therefore, the photodiode S (1,1) in the first row
To S (1,9) and the photodiodes S (5,1) to S (5,9) in the fifth row in the same column are connected to each other to connect the photodiodes S (2,1) in the second row. ~ S (2,9) and photodiodes S (6,1) ~ S (6,9) in the sixth row in the same column
Are connected to each other, and the photodiode S (3,1) in the third row is
It is also possible to connect each of -S (3,9) to the photodiodes S (7,1) to S (7,9) of the seventh row in the same column as each. With this configuration, the amplifiers A (1,1) to A
The number of (7,9), integrators I (1,1) to I (7,9), and analog switches SW (1,1) to SW (7,9) are, for example, 63 to 36, respectively.
Can be reduced to individual pieces.

In this way, the television receiver 1 projects an inclined pattern having a predetermined brightness at each position corresponding to the photodiodes S (1,1) to S (7,9), and the projected pattern is provided by the photodiode S ( It will be described that the position information of the electron beam is calculated by detecting each of 1,1) to S (7,9).

As shown in FIG. 5, it is assumed that a video signal having a pattern in which the brightness changes linearly with time t is supplied to the television receiver. If the beam of the television receiver is not displaced, the pattern is projected on the television receiver at the beam position P corresponding to the time t, as shown in FIG. 6A. Here, if the brightness Q is detected at P ₀ , the brightness level Q ₀ can be obtained.

It is assumed that the beam of the television receiver is shifted to the right.
Then, as shown in FIG. 6B, the pattern is displayed on the television receiver by shifting to the right as a whole. Here, when the brightness Q is detected at the same position P ₀ as the position where the brightness level is detected in FIG. 6A, the brightness level becomes Q ₁ .

Suppose the beam of the television receiver has been offset to the left.
Then, as shown in FIG. 6C, the pattern is displayed on the television receiver with the pattern shifted to the left. Here, when the brightness Q is detected at the same position P ₀ as the position where the brightness level is detected in FIG. 6A, the brightness level becomes Q ₂ .

In this way, if a video signal having a pattern in which the signal level changes linearly with time t is supplied and the brightness of the pattern displayed by this video signal is detected at the same position, the beam is output from this brightness level. You can see the position shift. If the beam is shifted to the right, the brightness level at position P ₀ is reduced to Q ₁ , as shown in FIG. 6B, and if the beam is shifted to the left, as shown in FIG. 6C, The brightness level at position P ₀ increases to Q ₂ . The change in the brightness level at the position P ₀ is proportional to the beam position shift. The accuracy of the measurement depends on the rate of change of the brightness level of the pattern.

In the above description, for ease of understanding, if the change in the input level of the video signal is linear, the luminance level Q can also be detected linearly. However,
The output level of the photodiode does not change linearly with the input signal level, as shown in FIG. 7A. Therefore, as shown in FIG. 7B, a value at which the output of the photodiode changes linearly corresponding to the position of the electron beam is calculated and stored in advance in the memory, and the input signal level is set based on the output of this memory. I am trying to change.

When detecting the positional deviation of the beam, see Figs. 8A and 8A.
Five types of patterns, pattern B and pattern L and pattern H respectively shown in FIG. 8C are used.

The first inclined pattern shown in FIG. 8A is a pattern in which the brightness increases linearly in both the horizontal and vertical directions. The second inclined pattern shown in FIG. 8B is a pattern in which the luminance decreases linearly in the horizontal direction and the luminance increases linearly in the vertical direction. The third inclined pattern shown in FIG. 8C is a pattern in which the brightness increases linearly in the horizontal direction and decreases linearly in the vertical direction.

When the first inclined pattern is projected, the upper left corner of the pattern becomes darkest and the lower right corner of the pattern becomes brightest, as shown in FIG. 8A. As shown by the broken line in FIG. 8A, the luminance in the diagonally upward right direction becomes equal. The brightness of the pattern becomes gradually brighter from the upper left to the lower right of the pattern, and the brightness shown by the solid line M ₁ in FIG. 8A becomes the median value (K _max / 2). It should be noted that K _max is the maximum brightness level during adjustment, and is the output of the photodiode when a video signal of, for example, 1VP-P is applied.

When the second inclined pattern is projected, the upper right corner of the pattern becomes darkest and the lower left corner of the pattern becomes brightest, as shown in FIG. 8B. As shown by the broken line in FIG. 8B, the luminance in the diagonally downward right direction becomes equal. The brightness of the pattern becomes gradually brighter from the upper right to the lower left of the pattern, and the brightness shown by the solid line M ₂ in FIG. 8B becomes the median value (K _max / 2).

When the third tilted pattern is projected, the lower left corner of the pattern becomes darkest and the upper right corner of the pattern becomes brightest, as shown in FIG. 8C. As shown by the broken line in FIG. 8C, the luminance in the diagonally rightward direction becomes equal. The brightness of the pattern gradually increases from the lower left to the upper right of the screen, and the brightness indicated by the solid line M ₃ in FIG. 8C becomes the median value (K _max / 2).

By using such first, second, and third tilt patterns, it is possible to obtain the positional deviation of the beam from the detection output of the luminance.

For example, in FIG. 9, the luminance K ₁ is obtained from the first tilt pattern, the luminance K ₂ is obtained from the second tilt pattern, and the third K ₃ is obtained.
It is assumed that the brightness K ₃ is obtained from the inclination pattern of. Based on these detection outputs, the position deviation of the beam from the origin 0, that is, the coordinates of K (x, y) are obtained.

That is, as shown in FIG. 8A, in the first tilt pattern, the brightness indicated by the solid line M ₁ is (K _max / 2), and the brightness on a line parallel to the solid line M ₁ is equal. With reference to the solid line M ₁ in FIG. 9 A, the rate of change with respect to the distance in the y direction from the solid line M ₁
If Kstep is used, the distance from the solid line M ₁ by b ₁ is K ₁ = b ₁ · Kstep, and the brightness is K ₁ . Thereby, the straight line l ₁ on the first pattern having the brightness of K ₁ is obtained as y = −x + b ₁ = −x + (K ₁ / Kstep).

Similarly, as shown in FIG. 9B, the straight line l ₂ on the second pattern having the brightness of K ₂ is obtained by the second tilt pattern.
Is calculated as y = x + b ₂ = x + (K ₂ / Kstep).

From the equations, the x-coordinate of the beam position deviation K (x, y) can be obtained by the following equation.

The change rate Kstep is the change rate of luminance. This rate of change Kstep
Is the luminance of the pattern L of _{(K max / 2-Kstep)} (K max / 2
+ Kstep) and the luminance pattern H is used. That is, assuming that the brightness of the pattern L having the brightness of (K _max / 2−Kstep) is K _L and the brightness of the pattern H having the brightness of (K _max / 2 + Kstep) is K _H , K _H −K _L = 2 · Kstep. Becomes Substituting the change rate Kstep obtained by this equation into the equation, Therefore, the x coordinate of the beam position deviation K (x, y) is calculated from the equation.

The y-coordinate of the beam position deviation K (x, y) is, as shown in 9A, a straight line l _{1 at} which the brightness obtained by the first tilt pattern is K _1, and as shown in FIG. 9C, It can be obtained in the same manner as in the case where the x coordinate is obtained by the following equation from the straight line l ₃ whose brightness is obtained by the inclination pattern of ₃ and which is K ₃ .

When detecting the positional deviation of the beam, for example, a first tilt pattern is projected for each screen, a pattern L having a luminance of (K _max / 2-Kstep) is projected, and a second tilt pattern is projected ( A pattern H having a luminance of K _max / 2 + Kstep) is projected, and a third tilt pattern is projected. In this way, the measurement is completed with 5 screens.

Convergence is measured as described above for red, green,
Blue beam misalignment (x _R , y _R ), (x _G , y _G ), (x _B ,
y _B ), and the difference between the red beam R and the blue beam B with respect to the green beam G which is the center beam. In other words, convergence in the horizontal direction, determined as x _B -x _R, convergence in the vertical direction is determined as y _B -y _R.

A measurement method in the case of measuring the deflection and the convergence using this one embodiment will be described with reference to the flowchart shown in FIG.

First, the relationship between the sensor and the brightness is obtained (step), and based on this characteristic, the sensor changes linearly with respect to the beam position at each sensor position.
Third inclined pattern and (K _max / 2-Kstep) pattern L, to create a five patterns of the pattern H in the _{(K max / 2 + Kstep)} ( step).

These patterns are displayed on the screen, and the pattern position is adjusted so that the centers of the patterns corresponding to the sensors at the center of the screen match (step).

Only the pattern portion is made green and five types of patterns are projected (step), and the sensor outputs of the five types of patterns are measured (step), and the beam position deviation of the green beam G is calculated by the output of this sensor ( Step). From the beam position shift coordinates of the green beam G, the adjustment amount of the deflection system such as the vertical and horizontal PIN distortions can be calculated.

Only the pattern portion is made red and five types of patterns are projected (step), the sensor outputs of the five types of patterns are measured (step), and the beam position deviation of the red beam R is calculated by the output of this sensor (step). ).

Only the pattern part is made blue and five types of patterns are projected (step), the sensor outputs of the five types of patterns are measured (step), and the beam position deviation of the blue beam B is calculated by the output of this sensor (step). ).

The adjustment amount of the deflection system is calculated based on the beam position deviation of the green beam G, and the misconvergence of the red beam R and the blue beam B is calculated with the sensor beam G as the center (step).

In the above description, a pattern in which the brightness changes in an oblique direction is used as the brightness inclination pattern for detecting the beam position deviation, but a pattern in which the brightness changes in the horizontal and vertical directions may be used. .

〔The invention's effect〕

According to the present invention, a tilted pattern is generated on the screen, and the tilted pattern is received by a sensor arranged at a predetermined position, so that the beam position can be measured with high accuracy without using a color camera. Further, since it is not necessary to use a color camera, the device is small and inexpensive. Further, the beam position can be similarly measured by the PAL method or the NTSC method.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall configuration of an embodiment of the present invention,
FIG. 2 is a perspective view used for explaining the mounting of the pickup in one embodiment of the present invention, FIG. 3 is a plan view used for explaining the arrangement of the sensors in one embodiment of the present invention, and FIG. The connecting portion of the sensor output portion in the embodiment, FIGS. 5, 6 and 7 are graphs used for explaining one embodiment of the present invention, and FIGS. 8 and 9 use one embodiment of the present invention. FIG. 10 is a schematic diagram used for explaining the case of measuring the beam position deviation by means of FIG. 10, and FIG. 10 is a flow chart used for explaining the case of performing the convergence adjustment using the embodiment of the present invention. Description of main symbols in the drawings 1: Television receiver, 3: Computer, 4: Pickup, S (1,1) to S (7,9): Photodiode.

Claims (1)

[Claims] 1. A pattern generating means for generating an inclined pattern in which a brightness level gradually changes at a predetermined change rate so that a change in the brightness level at a predetermined position and a beam shift correspond to each other, and a measured object. A sensor is provided for detecting the brightness level at a predetermined position on the surface of the color cathode ray tube, and it has a pickup means and a calculation means for calculating the positional deviation of the beam based on the detection output of the sensor. , The inclination pattern is projected on the tube surface of the color cathode ray tube to be measured, the pickup means is attached to the tube surface of the color cathode ray tube to be measured, and the brightness at a predetermined position on the tube surface of the color cathode ray tube is measured. The level is detected, and the calculation means uses the correspondence between the change in the brightness level at the predetermined position and the deviation of the beam to determine the brightness at the predetermined position on the tube surface of the color cathode ray tube to be measured. It performs an arithmetic operation for converting the change in the level of positional deviation of the beam from the reference position,
A beam position shift measuring device for determining the beam position shift of the color cathode ray tube to be measured.