JPH01122546A - Beam misregistration measuring device - Google Patents

Abstract

PURPOSE:To prevent the electromagnetic effect from a cathode-ray tube and simultaneously detect the misregistration of each color by arranging a color sensor against the tube face via optical fibers and detecting the brightness for each color on the tube face. CONSTITUTION:The light intensity at the preset position on the tube face 2 of a color cathode-ray tube 1 is picked up 3, and this detection signal is converted 4 into the preset signal. On the other hand, the preset image signal to display the position measuring pattern is fed to the tube 1 from a position measuring pattern generator 5. The pickup device 3 is provided with multiple optical fibers 6 and a color sensor S corresponding to them, the sensor S has a light receiving section 7 consisting of elements 7A-7D. The image signal with the signal level changed with time at the fixed increase rate is fed to the tube 1 from the device 5, thereby the brightness of the displayed pattern is detected at the preset fixed position, and the misregistration of an electron beam is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a beam position deviation measuring device suitable for use in adjusting the deflection and convergence of a color cathode ray tube constituting a television receiver or the like.

B6 Summary of the Invention The present invention relates to a beam position deviation measuring device used for adjusting the deflection and convergence of a color cathode ray tube constituting a television receiver, etc. , is equipped with a color sensor that detects the brightness of each color of blue, and by installing this color sensor via an optical fiber that transmits the tactility of the position measurement pattern, the electron beam of each hue of the color cathode ray tube can be detected. The positional deviation from the reference position is measured at the same time, and the distance between the color sensor and the tube surface is secured to avoid electromagnetic influence from the tube surface on the color sensor, and the positional deviation of the electron beam is measured. Quick ■.

The present invention provides a beam position deviation measuring device that can realize highly accurate measurement.

C9 Prior Art Conventionally, the deflection and convergence of a color cathode ray tube that constitutes a television receiver, etc. is adjusted by displaying a predetermined dot pattern on the tube surface of the color cathode ray tube, and photographing this dot pattern with a color camera. By this, red,
The positional information of the electron beam is detected by finding the center of each blue and green dot, and the scanning is performed based on this positional information.

However, in order to detect the positional information of the electron beam in this way, it is necessary to arrange a high-resolution color camera with high precision, and it is also necessary to use the image immersion obtained from the color camera. Since complex calculations are required to detect this, there is a problem that the device becomes large and expensive.

Therefore, in order to solve the problems mentioned in item 1, the applicant of the present application first proposed the following in Japanese Patent Application Laid-Open No. 62-62692 as a beam position deviation measuring device used for adjusting the deflection and convergence of color cathode ray tubes. We are proposing something configured as described in the official gazette.

As shown in FIG. 19, this beam position deviation measuring device is used to
A pickup device with a plurality of optical sensors built in at predetermined positions of 02 and 03 are arranged facing each other, and a monochromatic position measurement pattern having a predetermined brightness gradient is placed on the piping surface 102 at a position corresponding to the registered optical sensor. By displaying the information, the position information of the electron beam falling at the position corresponding to each of the above-mentioned optical sensors can be detected from the luminance multiplied by the output from the optical sensors. That is, since the position measurement pattern has a predetermined gradient, the relative positional relationship between the optical sensor and the position measurement pattern can be detected from the luminance signal output by the optical sensor. Since the optical sensor is arranged at a predetermined position, the positional displacement of the position measuring pattern with respect to the optical sensor is detected as the positional displacement of the electron beam.

In this way, by individually measuring the positional deviation of the electron beam for each color of red, blue, and green, and adjusting each electron beam based on the measurement results,
Deflection and convergence adjustment of the color cathode ray tube is completed.

D0 Problems to be Solved by the Invention Incidentally, in the beam position deviation measuring device as described above, the pink amplifier device 103 is connected to the tube surface 102.
It is placed in close contact with the Therefore, accurate brightness measurement may not be possible due to the influence of electromagnetic noise such as a discharge phenomenon within the bulb of the color cathode ray tube. If the brightness measurement is not performed accurately in this way, it will not be possible to maintain high accuracy of the device information made up of the brightness information output by this optical sensor, making it difficult to accurately detect the positional deviation of the electron beam. Can not.

Further, since the optical sensor cannot distinguish the color of light, it is necessary to display the position measurement pattern in a single color, switch the electron beam for each color, and measure each color individually. Therefore, electron beams displaying different colors are measured temporally apart from each other. Therefore, when measurement conditions such as the temperature of the color cathode ray tube change over time, the electron beams of each hue are measured under different measurement conditions, making it impossible to perform accurate deflection and convergence adjustment.

Therefore, the present invention is proposed by further improving the beam position shift measuring device proposed by the applicant in 1 above. Another object of the present invention is to provide a beam position deviation measuring device that can simultaneously measure positional deviations from a reference position for a plurality of electron beams of each hue.

E9 Means for Solving the Problems In order to achieve efficient distribution, in the beam position deviation measuring device according to the present invention, A plurality of optical fibers are arranged such that one end thereof faces each other and transmit the light emitted from the tube surface to the other end, and the other end of the optical fiber is provided correspondingly to this optical fiber, and the light transmitted by this optical fiber is provided. A color sensor that simultaneously detects the intensity of each color of red, green, and blue;
position measurement pattern generating means for displaying a position measurement pattern having a predetermined brightness gradient at a position on the tube surface corresponding to one end of the optical fiber; ``Conversion means for converting into a position signal representing the relative position between one end side of the optical fiber/N and the position measurement pattern, and based on the position signal, one end of the optical fiber on the tube surface is provided. The present invention is characterized in that a positional deviation of the electron beam corresponding to each color of the color cathode ray tube from a reference position at a position corresponding to the side is detected.

29 Effects In the beam position deviation measurement device according to the present invention, the color sensor identifies the colors that constitute the position measurement pattern displayed on the screen and detects the brightness of each color of red, green, and blue. , the positional deviation of the electron beam of each hue from the reference position is simultaneously detected, and this color sensor also detects -
Since it is installed via an optical fiber to the 1-distribution surface, the distance between the 1-distribution sensor and the 1-distribution surface is maintained, and the Electromagnetic influence from the color cathode ray tube on the detection of pattern brightness is prevented.

G. Examples Specific examples of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the beam position deviation measurement device according to the present invention includes a pink amplifier device 3 that detects the light intensity emitted from the tube surface 20 of the color cathode ray tube 1 at a predetermined position, and a color cathode ray tube 1 to be adjusted. , to which the output signal of the pink-up device 3 is sent, a conversion device 4 serving as a conversion means for converting this output signal into a predetermined signal, and a predetermined image for displaying a position measurement pattern on the color cathode ray tube 1. The position measurement pattern generating device 5 serves as a position measurement pattern generation means for supplying signals.

As shown in FIGS. 1 and 2, the pickup device 3 is composed of a plurality of optical fiber halos and a color sensor S provided corresponding to the optical fiber 6.

The optical fibers 6 are arranged in such a way that one end side is two-dimensionally arranged, and each time this one end side is opposed to the tube surface 2, light emitted from the tube surface 2 at each position is transmitted to the other end side. be done. The number of optical fibers is determined by the number of locations on the tube surface 2 where the positional deviation of the electron beam from the reference position is to be detected. That is, - the number of detection points in the horizontal direction and the number of detection points in the vertical direction on the tube surface 2 is multiplied by the total number, for example, 25.
(5 x 5) books or 63 (7 x 9) books, etc.

As shown in FIG. 3, the force radial sensor S has a light receiving section 7 consisting of first to fourth light receiving elements 7A, 7B, 7c and 7°, and these light receiving elements 7^.

7. Monochromatic filters are provided on the light receiving surfaces of 7c and 7D, respectively. That is, a red filter 8R is provided on the light-receiving surface "2" of the first light-receiving element 7, which passes only red light, and a light-receiving surface -F of the second light-receiving element 7B is provided with a red filter 8R that transmits green light. Green filter 8 that only passes through
A blue filter 8B that allows only blue light to pass is provided on the light receiving surfaces of the third and fourth light receiving elements. Also, “two-signature photodetector?” A, 7I+, 7
゜The output signals of the ID can be taken out independently from the plurality of terminal sections 9. The color sensor S is disposed on the other end side of each of the optical fibers 6 so as to receive the light transmitted by the optical fiber 6 and emitted from the tube surface 2.

When the pickup device 3 configured in this manner is placed at a predetermined position with respect to the tube surface 2, one end ijll of the optical fiber halo facing the tube surface 2 and the tube surface 2 are connected to each other. , are arranged at predetermined intervals. Therefore,
Only the light emitted from a predetermined range of the tube surface 2, that is, the measurement range, is made to enter the optical fiber 6. The luminance of the measurement range of the tube surface 2 is transmitted to the light receiving section 7 of the color sensor S through the optical fiber 6.

At this time, if a white pattern is displayed on the tube surface 2, the red, green, and blue lights that make up the white pattern are transmitted through the fiber 6 while being diffused. red, green,
White light composed of light of each color of blue is projected.

Of the lights constituting this white light, red light is received by the first light receiving element 7^, and green light is received by the second light receiving element 7^.
The blue light is received by the light receiving element 7B, and the blue light is received by the third and fourth light receiving elements 7° and 1o. The reason why there are two light-receiving elements that receive blue light is that the sensitivity of these light-receiving elements to blue light is low.

As shown in FIG. 4, the conversion device 4 has a first light receiving element 7A, a second light receiving element 711, and a third and fourth light receiving element corresponding to all of the two-signal color sensors S. Amplifier AR (1) to which the output signals of elements 7° and 7o are supplied
, AG (1) and AB (1) to AR<nf,
Aa (n) and All (n) are provided. The output signals of all these amplifiers AR, 80, and All are connected to integrators TR(1), Ia(1), and III(1), respectively.
〜IR(n), Ic+(n) and In(n)
sent to. The output signals of the above-mentioned integrators 1p, Ia, and In are respectively output from analog switches SWR(1) and
SWa (], ) and SWl+ (1) to SWR
(n), SWa (n) and S''#++ (n), it is switched to l1lfj and sent to the A/D converter lO. This A/D converter 10 converts it into a digital signal. The signal is sent to computer 12 via T10ponite 11.

The position measurement pattern generator 5 supplies a predetermined video signal to the color cathode ray tube 1 and generates a plurality of position measurement patterns P (1) to P (n) on the tube surface 2. It is displayed at a predetermined position corresponding to one end side of the plurality of optical fibers 6. As shown in FIG. 5, this position measurement pattern P has a rectangular shape of a predetermined size corresponding to the measurement range of the tube surface 2, and has a predetermined brightness gradient within this rectangle. That is, there is a brightness gradient of a predetermined gradient in the horizontal direction of the color cathode ray tube 1, indicated by the X coordinate in FIG. 5, and a predetermined gradient in the vertical direction of the color cathode ray tube 1, indicated by the X coordinate in FIG. It has a brightness gradient of In FIG. 5, the position measurement pattern P
The brightness of is shown in two coordinates orthogonal to the above X and y coordinates. Therefore, in FIG. 5, Po. The corner of the lower luminance side of both the X and y coordinates indicated by is the part of the position measurement pattern P that has the lowest luminance, and the diagonal of the rectangle that forms this corner and the position measurement pattern P is The corner indicated by P(Wy1) in FIG.

Next, in the video camera according to the present invention configured as described above, the color cathode ray tube 1
The principle and procedure for measuring the positional deviation of the electron beam from the reference position will be explained.

As shown in FIG.
A video signal whose signal level changes at a constant rate of increase (or rate of decrease) is supplied. At this time, if the electron beam of the color cathode ray tube 1 is not displaced, a pattern having a brightness gradient at the beam position p corresponding to the time t will be formed on the tube surface 2, as shown in FIG. Is displayed.

Here, if the brightness q is detected at a position +11o using an optical sensor, the brightness level qo can be obtained.

When the electron beam of the color cathode ray tube 1 is shifted to the right in FIG. As a result, a pattern having a luminance gradient is displayed shifted to the right. Here, if the brightness q is detected at the same position pO as the position where the brightness level is detected in FIG.
A brightness level q1 different from o is obtained.

Furthermore, when the electron beam of the color cathode ray tube 1 is shifted to the left in FIG. hand,
A pattern having a brightness gradient is displayed shifted to the left.

Here, when the brightness q is detected at the same position po as the position where the brightness level is detected in FIG. 7, the brightness level Qo
A brightness level q2 different from that obtained is obtained.

In this way, a video signal whose signal level changes at a constant increase rate (or decrease rate) with time t is supplied, and the brightness of a pattern displayed by this video signal is detected at a predetermined constant position. By doing so, the positional deviation of the electron beam can be detected from the detected brightness level.

In the above description, in order to simplify the explanation, it is assumed that the brightness level q detected by the optical sensor changes in proportion to the change in the signal level of the video signal. However, as shown in FIG. 0, the brightness level detected by the optical sensor may not change in proportion to the change in the brightness level of the video signal. In such a case, as shown in FIG. 1I, the luminance level detected by the optical sensor changes at a constant rate of increase (or decrease) in accordance with the position p of the electron beam. The rate of change (or rate of decrease) of the signal level of the video signal may be controlled.

In the beam position deviation detection device according to the present invention, when detecting the position deviation of the electron beam from the reference position, the first to third position measurement patterns as shown in FIGS. 12 to 14 are used. P1. P2゜P3, fourth position measurement pattern P+, fifth position measurement pattern P, total 5
Various position measurement patterns are used. Each of these position measurement patterns is formed by uniformly projecting electron beams of each hue of red, green, and blue, and is therefore formed as a white pattern.

As shown in FIG. 12, in the first position measurement pattern P, the luminance increases at a constant rate of increase with time t in the horizontal and vertical directions indicated by the X and Y coordinates in FIG. This is an increasing pattern. As shown in FIG. 13, in the second position measurement pattern P2, the luminance decreases at a constant rate of decrease with time t in the horizontal direction indicated by the X coordinate in FIG. 13, and is indicated by the Y coordinate. This is a pattern in which the brightness increases at a constant rate of increase with time t in the vertical direction. As shown in FIG. 14, in the third position measurement pattern P3, the luminance increases at a constant rate of increase with time t in the horizontal direction indicated by the X coordinate in FIG. 14, and is indicated by the Y coordinate. This is a pattern in which the brightness decreases at a constant rate of decrease with time t in the vertical direction.

In the first position measurement pattern P□, the 12th
In the figure, the display start part of the horizontal and vertical pattern, not indicated by P (rru. Then, on a straight line that is the same distance from the darkest part and the brightest part of this pattern, indicated by M1 in FIG. 12, the median brightness of this pattern is This median value is set to (K, /2), assuming that the maximum brightness obtained on the tube surface 2 is 14.

In the second position measurement pattern P2, the 13th
In the figure, P tm+. The middle area of the pattern becomes darker at the end of the display of the pattern in the horizontal direction and the start of the display of the pattern in the vertical direction, as indicated by P and -E in FIG. The display start part and the display end part of the pattern in the vertical direction become brighter as well. Then, on a straight line indicated by M2 in FIG. 13, which is the same distance from the darkest part and the brightest part of this pattern, is the median brightness value of this pattern (K t + n
a y+/2) is obtained.

In the third position measurement pattern P3, the fourteenth
The part where the pattern starts to be displayed in the horizontal direction and the part where the pattern ends in the vertical direction, indicated by Po+++n+ in the figure, is also darkened, and the 14th
In the figure, the portion where the display of the pattern ends in the horizontal direction and the portion where the display of the pattern starts in the vertical direction, indicated by P (a) in the figure, becomes brighter as well. and,
The median brightness value of this pattern is (K (1)
/2) is obtained.

Such first to third position measurement patterns PI
, P2 + P3 and the above fourth. The fifth position measurement patterns PL and PH are connected to the plurality of color sensors 5(1).
Displayed at predetermined positions corresponding to all of S (n),
Detect brightness. That is, the first position measurement patterns P+(1) to P+(n).

Second position measurement patterns P2 (1) to P2(n
), third position measurement pattern P3 (1) to P3
(n), fourth position measurement pattern P1□(1) to P+, (n), and fifth position measurement pattern PH(+>
The brightness is detected by sequentially displaying P□(n).

At this time, the luminance detected by the color sensor S is independently detected for each of the colors red, green, and blue forming the white pattern.

An arbitrary light receiving element of an arbitrary color sensor S among the plurality of color sensors 5(1) to S(n) will be described. That is, as shown in FIG. 15, in the first position measurement pattern P1, a luminance of 2 is detected, and as shown in FIG. 16, in the second position measurement pattern P2, a luminance of 2 is detected. is detected, and as shown in FIG. 17, in the third position measurement pattern P3,
Assume that 3 is detected as the brightness. The first to third position measurement patterns P, P2. At P3, the brightness is constant on a straight line parallel to the straight line portions indicated by M+, M2, and M3 in FIGS. 15 to 17, where the brightness is the center brightness, that is, (K1(a)/2).

In the first position measurement pattern P1, the distance b1 in the vertical direction between the straight line indicated by β1 in FIG. 15 whose luminance is the above-mentioned luminance and the straight line indicated by MI in FIG. 15 whose luminance is the center luminance is , the rate of increase with respect to the vertical distance is Ks T
If E P, then -S, ・Ks T E P
......(Equation 1). That is, in the first position measurement pattern P, the straight line indicated by β1 in FIG.・・・・・・
(Second equation) Similarly, in the second position measurement pattern P2, the brightness is 2 to the above brightness and the straight line indicated by β2 in FIG. 16 and the brightness is the center brightness. If the vertical distance b2 from the straight line indicated by M2 in the middle and the increase rate with respect to the vertical distance are KsTpP, then K2-b2 ・KSTEP・・・・・・・・・(3rd
formula). That is, in the second position measurement pattern P2, the brightness is 2 to the above brightness, and I
The straight line indicated by 12 is y=x+b2 =x + (K2/Ks T E P )...
...(4th equation) From the 2nd equation and the 4th equation, regarding the positional deviation K (x, y) of the electron beam from the reference position, x = (KI
K2)/ (2・KsTEp)・・・・・・・・・(
Equation 5) is obtained as:

The increase rate KSTEP is the fourth position measurement pattern P I having a luminance of (K+TIII=s/2 K sT Ep ).

and (Kn+++x / 2 + K S T E P )
The fifth position measurement pattern P having a luminance of 2.

It can be found by using . That is, if the brightness of the fourth position measurement pattern P+ in -1- is KL and the brightness of the fifth position measurement pattern PH in 1 is KH, then KH- is 1, -2·KsTEP... ...(6th formula)
becomes. The increase rate Ks T E determined by this 6th equation
Substituting P into the fifth equation, X = (KI K2 ) / (KM
KL )・・・・・・・・・(7th formula) The positional deviation of the above electron beam K (x, y)
The X coordinate of is determined.

The X coordinate of the position deviation K (x, y) of the electron beam is between the straight line indicated by βl in FIG. From the straight line indicated by I13 in FIG. 17 where the luminance is 3 to the above luminance in the measurement pattern P3, 'J = (KI K3) / (Ko K1
．． )・・・・・・・・・(Equation 8)

In this way, the entire area of the tube surface 2 is covered with red,
The positional deviation of the electron beam from the reference position is measured for the electron beam of each hue of green and blue.

Refer to the flowchart shown in FIG. 18 for the procedure for measuring the positional deviation of an electron beam and measuring the deflection and convergence of a color cathode ray tube using the beam positional deviation measuring device according to the present invention as described above. I will explain.

First, in step STI, the characteristics of the color sensor S, that is, the relationship between the output signal level of the color sensor S and the luminance of the tube surface 2, are determined, and in step ST2, each of the characteristics is determined based on the characteristics of the color sensor S. The first to third position measurement patterns P1.in which the output signal level of the force sensor array S changes at a constant rate of increase (or rate of decrease) with respect to the position of the electron beam for each position of the color sensor. P2 + P3 and the above 4th. Fifth
Create position measurement patterns PL and PH.

In step ST3, each position measurement pattern is generated on the tube surface 2 using the position measurement pattern generator 5.
Adjust the display position of the two-signature position measurement pattern so that the position measurement pattern at the center of the tube surface 2 matches one end of the optical fiber halo at the center of the pickup device 3.

In step ST4, the first to fifth position measurement patterns P1+P2, P3, P+, .

are sequentially displayed, the brightness is detected for all the position measurement patterns, and the detected brightness signal for each color is stored in the computer 12 of the conversion device 4. At this time, all the light receiving elements 7A, 7B, and 7° of all the color sensors 5(1) to S(n).

The output signal of 7D is sent to the analog switch S W R (1
), SWa (1) and SWB (n) to SW
R(n), SWa (n) and SWB (n), the A/D converter 10. I1 above
The data is sent to the computer 12 via the 0 port 11.

In step ST5, the computer 12 calculates the positional deviation of the electron beam of each hue of red, green, and blue from the reference position based on all the stored luminance signals,
A position signal representing the relative positional relationship between the position measurement pattern and one end side of the optical fiber 6, that is, the positional deviation of the electron beam is obtained.

In step ST6, from the position signal of the green electron beam, the vertical and horizontal P■N of this electron beam is determined.
The adjustment amount of the deflection system such as distortion is calculated. Next, the amount of misconvergence of the red electron beam and the blue electron beam is calculated using the green electron beam as a reference.

In the above description, a pattern in which the brightness changes diagonally on the screen surface is used as the position measurement pattern, but it is also possible to use a position measurement pattern in which the brightness changes in the horizontal and vertical directions. You may also do so.

H9 Effects of the Invention As described above, according to the beam position deviation measuring device according to the present invention, a position measurement pattern is displayed on the tube surface of a color cathode ray tube, and the brightness of this position measurement pattern is adjusted to the brightness of a predetermined position. By detecting using a color sensor, the positional deviation of the electron beam from the reference position can be measured with high precision without using a color camera. Therefore, the device is smaller and cheaper, and P
In both the AL system and the NTSC system, the positional deviation of the electron beam can be measured in the same way.

Furthermore, in the beam position deviation measuring device according to the present invention, the color sensor identifies the colors that constitute the position measurement pattern displayed on the tube surface and detects the brightness of each color.

Therefore, the positional deviations of multiple electron beams in each color layer from the reference position are detected simultaneously, so the positional deviations of the electron beams can be measured without being affected by temperature changes in the color cathode ray tube over time. Highly accurate deflection and convergence adjustments can be made.

Moreover, since the color sensor is disposed with respect to the tube surface via an optical fiber, the distance between the color sensor and the tube surface is maintained.

Therefore, measurement accuracy will not be reduced due to electromagnetic influence from the color cathode ray tube on the pickup device including the color sensor.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing the configuration of the main parts of the beam position deviation measuring device according to the present invention, and FIG. FIG. 3 is a front view showing the structure of an example of the color cathode ray tube facing the tube surface; FIG. 3 is a front view showing the structure of a color sensor forming the pickup device;
The figure is a block diagram showing the configuration of a converting device constituting the beam position deviation measuring apparatus, and FIG. 6 to 9 are diagrams showing the principle of detecting the positional deviation of an electron beam by the beam positional deviation measuring device according to the present invention, and FIG. 6M shows the relationship between time and video signal level in the position measurement pattern. FIG. 7 is a diagram showing the brightness detected when there is no positional deviation of the electron beam, and FIG. 8 is a diagram showing the brightness detected when there is positional deviation in one direction of the electron beam. FIG. 9 is a diagram showing the brightness detected when there is a positional shift of the electron beam in the other direction. FIG. 10 is a diagram showing the relationship between the video signal level and the detected luminance in the color sensor constituting the beam position deviation measuring device according to the present invention, and FIG. 11 corresponds to the position on the tube surface of the color cathode ray tube. FIG. 4 is a diagram showing changes in the video signal level in which the brightness changes at a constant rate of increase. FIG. 12 is a diagram showing a first position measurement pattern used in the beam position deviation measuring device according to the present invention.
FIG. 3 is a diagram showing a second position measurement pattern used in the beam position deviation measuring device, and FIG. 14 is a diagram showing a third position measurement pattern used in the beam position deviation measuring device. , FIG. 15 is a diagram showing a state in which brightness is detected in the first position measurement pattern, and FIG. 16 is a diagram showing a state in which brightness is detected in the second position measurement pattern. Figure 17 is the third figure above.
FIG. 3 is a diagram showing a state in which brightness is detected in a position measurement pattern of FIG. FIG. 18 is a flowchart 1 to 1 showing steps 1ll'i when adjusting the deflection and convergence of a color cathode ray tube using the beam position shift measuring device according to the present invention. FIG. 19 is a partially cutaway perspective view showing the configuration of a conventional beam position deviation measuring device. 1...Color cathode ray tube 2...Tube surface 3...Pickup device 4...Conversion device 5... ...Position measurement pattern generator 6...
・・・・・・Optical fiber S・・・・・・Color sensor

Claims (1)

[Scope of Claims] A plurality of optical fibers, one end of which is arranged opposite to another at a predetermined position on the tube surface of a color cathode ray tube, and which transmits light emitted from the tube surface to the other end; It is provided corresponding to the optical fiber, and the red, green, and
a color sensor that simultaneously detects the intensity of each color of blue; a position measurement pattern generating means that displays a position measurement pattern having a predetermined brightness gradient at a position on the tube surface corresponding to one end side of the optical fiber; converting means for converting the signal output by the color sensor into a position signal representing a relative position between one end side of the optical fiber and the position measurement pattern for each color; A beam position deviation measuring device for detecting a positional deviation of an electron beam corresponding to each color of the color cathode ray tube from a reference position at a position corresponding to one end side of the optical fiber on the surface.