JPH0156594B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a convergence measuring device for an in-line color picture tube, and in particular, an object of the present invention is to efficiently and accurately measure convergence.

A method for measuring the convergence of a conventional in-line color picture tube will now be described. Here, convergence refers to the color picture tube 1 as shown in Figure 1.
Electron beams of three colors, that is, blue, green, and red (hereinafter referred to as B, G, and R) emitted from an electron gun 2 sealed in This is the degree of overlapping of electron beams when riding on the phosphor coated on the inner surface 4 of the panel of a color picture tube.

Generally, this convergence measurement is carried out by projecting a crosshatch pattern from a signal generator 6 on the screen of the color picture tube via a socket 5 attached to the color picture tube, and detecting the B, G, and This is done by reading the difference in the center coordinates of each crosshatch pattern. An example is shown in FIG. Figure A shows a crosshatch pattern when the convergence is out of alignment in the detection unit 10, and the coordinates of the intersections of the vertical lines and horizontal lines of B, G, and R do not match. B in the same figure shows a crosshatch pattern when convergence is good, and the coordinates of the intersection points match, and in this case, a good screen can be obtained.

A conventional automatic convergence adjustment device for an in-line color picture tube will now be described. In this example, as shown in FIG. 3, a convergence adjustment magnet 12 is attached to the outside of the network of the picture tube 11, and this magnet 12 is connected to a pulse motor 14 via a drive device 13. A detection device 16 that detects the crosshatch pattern projected on the picture tube 11 via the lens 15 is connected to the picture tube 1.
It is placed in front of 1. A signal processing device 17 that binarizes the detection signal is connected to the detection device 16, and a control device 18 receives the signal from the signal processing device 17 and sends out a control pulse to rotate the pulse motor 14. Pulse motor 14
and the signal generator 6.

To adjust the convergence in such a device, the crosshatch pattern projected on the picture tube 11 is detected by the detection device 16 through the lens 15, and the detected signal is binarized by the signal processing device 17. Then, the center coordinates of each of the crosshatch patterns of B, G, and R are determined, and the pulse motor 1 is controlled by the control device 18 according to the amount of deviation of the center coordinates.
This is done by sending a control pulse to 4 and rotating the convergence adjustment magnet 12. That is, by determining the relationship between the rotation angle of the magnet 12 and the amount of movement of the electron beam in advance, the adjustment magnet 12 is rotated via the drive device 13 based on the relationship. This operation is performed by sequentially switching the B, G, and R crosshatch patterns from the signal generator 6.

The detection screen of the detection device 16 at this time is shown in FIG. Figure 4A is for one color, B, G, or R, and there is one intersection point between the vertical line and the horizontal line of the crosshatch pattern in the detection part, and the center coordinate C
can be easily determined. However, when the type of tube changes, as shown in Figure B, since the magnification of the lens remains constant, two or more (nine in the figure) intersections of the vertical and horizontal lines of the crosshatch pattern will enter the detection area. Become. In such a case, it is difficult to determine the center coordinates, so the magnification of the lens must be changed, which is extremely time-consuming.

Furthermore, in an in-line color picture tube 20 as shown in FIG. neck part 23 of
A magnetizing device consisting of a ring-shaped multipolar magnetizing coil 24 and a magnetizing power supply 25 attached to the magnetizing coil 24 is provided on the outside of the magnetizing device. In this case, the adjustment magnet and pulse motor of the picture tube 11 are not provided, but the other devices are arranged in the same way, and the same parts are designated by the same reference numerals. There is.

The method for this color picture tube 20 will be explained next. The center coordinates of the crosshatch pattern are detected by a detection device 16 consisting of a matrix camera through a lens 15, and then passed through a signal processing device 17.
The control device 18 sends B, G, and R switching signals to the signal generator 6 to sequentially switch the colors. The light-receiving section 26 of the detection device 16 has light-receiving elements arranged in a matrix, and the detection signal here is binarized by the signal processing device 17 to determine the center coordinates of each of B, G, and R. A current is applied to the ring-shaped magnetizing coil 24 to magnetize the ring-shaped magnetic body 22 according to the amount of deviation of the center coordinates. The magnitude and direction of the current flowing through the ring-shaped magnetized coil 24 are B,
The control device 18 determines the central coordinates of the G and R crosshatch patterns, and controls charging and discharging of the magnetizing power source 25.

In order to adjust the convergence in this way, the magnetic body 22 is first magnetized to saturation, and then gradually demagnetized until the convergence matches. The reason for using this method is to stabilize the magnetization, reduce the influence of external magnetic fields, suppress deterioration over time, and create a stable magnetic field over a long period of time. However, this method uses lens 1
Since the magnification of 5 is constant, the spread of the beam becomes large during saturation magnetization, so that there may be cases where no intersection point enters the light receiving section. Therefore, the above B, G,
The magnification of the lens 15 must be determined so that only one intersection point of each of the R crosshatch patterns is detected by the light receiving section 26.
FIG. 6 shows the positional relationship of the crosshatch pattern of the detection sections detected by the light receiving section 26. A in the figure shows the center coordinates of B, G, and R during saturation magnetization, which are shown as B _c , G _c , and R _c .
However, as mentioned above, in the signal generator, B,
Since G and R are switched, only one intersection point for each color is displayed on the detection unit 30. Next, the positional relationship of B, G, and R when demagnetized is shown in FIG. Since the magnification of the lens is constant, there is only one intersection point (B _c , G _c , R _c ) of each of the B, G, and R crosshatch patterns, and the detection accuracy is the same as in A of the same figure.
For convergence adjustment, it is necessary to further improve the accuracy, but with a magnification that allows only one intersection point during saturation magnetization, there is a limit to detection accuracy, and it is not possible to perform the more accurate detection required for convergence adjustment. Therefore, it is necessary to change the magnification of the lens each time as necessary, which is extremely time-consuming.

The present invention has been made in consideration of these points, and provides a convergence measuring device that can automatically change the magnification of a lens and can perform measurements efficiently.

The present invention will be described below with reference to the drawings. As shown in FIG. 7, regarding the convergence measuring device in the in-line color picture tube 20, the same parts as in FIG. 5 are given the same numbers. A pulley 41 is attached to a lens 15' attached to a detection device 16 for detecting a crosshatch pattern projected on a picture tube 20, and a pulse motor 4 connected to a control device 18 is attached to a lens 15'.
Pulley 43 and belt 44 fixed to the rotating shaft of No. 2
This constitutes a magnification changing device for the lens 15' which is interlocked via the lens 15'.

Convergence adjustment using such a device is performed as follows. First of all, signal generator 6
The B, G, and R crosshatch pattern signals are then switched and displayed on the screen of the picture tube 20. First, take out the B pattern and find its center coordinates, then take out the G pattern and find its center coordinates, then take out the R pattern and find its center coordinates. In this way, the crosshatch pattern is projected one color at a time, and the detection signal obtained from the light receiving section 26 is binarized by the signal processing device 17, and this binarized signal is subjected to arithmetic processing by the control device 18. Afterwards, B.
The charging voltage and current direction of the magnetizing power source 25 are determined according to the center coordinates of each of the G and R crosshatch patterns. Next, a magnetizing current is applied to the ring-shaped magnetizing coil 24 according to a signal from the control device 18, and the magnetic body 22 is saturated and magnetized in a direction to converge the electron beam. Thereafter, the B, G, and R crosshatch patterns are sequentially projected again, their center coordinates are determined, and the direction of the charging voltage and current of the magnetizing power source is determined again to discharge the magnet. In this way, by repeating the detection of the center coordinates of the crosshatch pattern for each color of B, G, and R, calculation of the magnetizing voltage and polarity, and discharge, the three color beams are gradually demagnetized so as to coincide.

Next, how to determine the magnification of the beam lens 15' will be explained. First, at the time of saturation magnetization, how much the center coordinates of the three color beams are shifted is determined, and only one intersection point of each beam is made to enter the light receiving section 26. In the light receiving section 26, photodiode arrays are arranged in a grid pattern, the grid spacing is 60 μm, and the number of grids is arranged in columns.
The photodetector used was made up of a total of 10,000 light-receiving elements, 100 light-receiving elements and 100 rows, and had a size of 6 mm x 6 mm.

Therefore, 1x lens 15' is 6mm x 6mm.
Only the center coordinates of the crosshatch pattern of the three color beams within the range of can be detected. By the way, if the magnetic body 22 has a structure with a sufficient convergence correction amount, the movement of the three-color beam in the case of saturation magnetization (the positions of B _c , G _c , and R _c shown in FIG. 6A and the position before saturation magnetization) The difference from the positions of B _c , G _c , and R _c ) is large, about 10 mm.
It will spread over an area of approximately 20mm x 20mm. Therefore, in the case of saturation magnetization, the zoom lens 15
When the magnification is set to 1/4, it becomes possible to detect the center coordinates of the three color beams within a range of about 24 mm x 24 mm on the screen of the picture tube 20. If the magnification is smaller than this, for example 1/6, the center coordinates of the three color beams will be detected in an area of approximately 36 mm x 36 mm on the panel surface of the picture tube 20, and up to the intersection of adjacent crosshatch patterns. This increases the possibility that the center coordinates of the three color beams cannot be accurately detected. Therefore, it is necessary to appropriately determine the lattice spacing of the crosshatch pattern and the amount of movement of the three color beams in the case of saturation magnetization.

Therefore, if the magnification at saturation magnetization is set to 1/4,
1 for each of the three colors at any saturation magnetization
Only two intersections enter the light receiving area. At this time, the detection accuracy of one bit of the light receiving element corresponds to approximately 240 μm on the screen of the picture tube 20. In the next demagnetization step, the B, G, and R crosshatch patterns gradually approach each other, but since the magnification of the lens is constant, the detection accuracy remains unchanged. However, in adjusting convergence, the above detection accuracy is insufficient, and the center coordinates of the three color beams must be brought close to about 100 μm. In other words, if the magnification of the zoom lens 15' is 1/4, one light receiving element is 60 μm, so on the screen of the picture tube 20,
The detection limit is a position error of 240 μm x 240 μm, or 0.24 mm x 0.24 mm, but it is generally necessary to keep this error to 0.1 mm x 0.1 mm or less.
In this state, it is not possible to converge the three color beams with sufficient accuracy. However, as the three color beams are demagnetized, they converge to one point, so the magnification of the zoom lens 15' can be increased. The rate of convergence, that is, the ratio of the range in which the center position of the three color beams spreads, is often less than 1/3 after the first demagnetization, so after the first demagnetization, the magnification of the lens is reduced. 1/3, 1/2 the second time, and so on, as the beam converges so that each of the B, G, and R crosshatch patterns fills the effective area of the light receiving section 26 and only one intersection point. Bye. If the magnification of the zoom lens 15' is 1x,
The detection accuracy of the center position of the three color beams on the screen of the picture tube 20 is 60 μm x 60 μm, or 0.06 mm x 0.06 mm.
Therefore, the accuracy is sufficient.

This lens magnification can be automatically changed as follows. In other words, in order to make the pattern that has entered the light receiving section 26 have one intersection point for each of the three colors and to spread over the entire effective area, a saturation magnetization or several demagnetization signal and the screen of the picture tube 20, which will be described later, are used. If the size or type of video signal is to be changed, the magnification of the zoom lens 15' is determined according to the type of video signal, and the control device 1
8 to the pulse motor 42, and via the pulley 43 and belt 44 fixed to the pulse motor 42, the zoom lens 15'
The lens magnification is automatically changed by rotating a pulley 41 fixed to the lens. In this example, the initial lens magnification of 1/4 is automatically changed to 1/2, and as a result, the detection accuracy is 120 μm per 1 bit of the light receiving element, which improves the convergence measurement accuracy. The accuracy can be automatically improved to the desired level. Of course, when detecting the center position of the three color beams, it is a matter of course that the position data is processed in consideration of the magnification of the zoom lens 15'.

In this way, B in the crosshatch pattern,
Since the detection accuracy can be automatically changed according to the position of the center coordinates of G and R, it is possible to automatically adjust the convergence from large pipes to small pipes, greatly improving efficiency. It is something that can be done.

Next, another embodiment of the convergence measurement apparatus shown in FIG. 8 will be described. The same parts as those in FIG. 3 are given the same reference numerals. color picture tube 11
lens 1 attached to a detection device 16 that detects the crosshatch pattern displayed on the screen of
A pulley 51 is attached to 5', and this pulley 51 is connected to a pulley 53 fixed to the rotating shaft of a pulse motor 52 connected to the control device 18 and a belt 5.
A magnification changing device for the lens 15' is configured to be interlocked via the lens 15'.

In order to measure convergence using the device formed in this way, the picture tube 1 is
1 is detected by the detection device 16, and the control pulse is controlled according to the amount of deviation of the center coordinates of B, G, and R, which is binarized and determined by the signal processing device 17. This is done by sending the signal from the device 18 to the pulse motor 14 and rotating the convergence adjustment magnet 12. However, if the tube types are different, the spacing of the crosshatch patterns will be different due to the difference in screen size, so there is a possibility that adjacent three-color beams will be detected, making it difficult to detect the center coordinates. Said lens 1
Pulley 51 attached to 5' and control device 1
Since the pulley 53 fixed to the rotating shaft of the pulse motor 52 receives control pulses from the control device 8, when a different pattern appears on the detection unit, the control device 18 that matches the pattern The magnification of the lens 15' can be automatically and easily changed by moving the pulley 51 in accordance with the output signal. Therefore, even if various crosshatch patterns with different intervals appear in the detection section, the magnification of the lens 15' can be automatically changed so that the center coordinates can be easily found in accordance with each pattern. Efficiency can be improved by comparison.

Determination of the magnification of such a lens 15' is performed by B.
This can be easily performed by storing a predetermined procedure in the control device 18 according to the position of each central coordinate of the G and R three color beams, thereby enabling precise measurement. In addition to the above-mentioned lens magnification changing device, various modified structures are possible in accordance with the gist of the present invention.

In the embodiments shown in FIGS. 7 and 8, the main configuration of the control device can be made common, and adaptation to each embodiment can be made possible by changing the control software. , or you can create your own.

As described above, according to the present invention, the detection accuracy can be automatically changed depending on the degree of convergence matching, that is, the position of the center coordinates of the three B, G, and R color beams, and the convergence can be automatically adjusted for each product type. It is possible to measure the color picture tube, improve work efficiency, and provide a color picture tube with good image quality.

[Brief explanation of drawings]

Figure 1 is a schematic explanatory diagram of a color picture tube, Figure 2 is a diagram showing a crosshatch pattern projected on the panel surface and the detection area, and Figure A shows a pattern in which B, G, and R do not match. B in the same figure is B, G, R.
FIG. 3 is a diagram showing the configuration of a conventional picture tube convergence measuring device.
Figure 4 is a diagram showing the relationship between a pattern of one color, B, G, or R, and a detection area. Figure A shows a pattern with one intersection of vertical and horizontal lines, and Figure B shows a pattern with multiple A diagram showing the pattern of intersection points, FIG. 5 is a diagram showing the configuration of another conventional convergence measuring device,
Figure 6 shows a crosshatch pattern, Figure A is a diagram when magnetized to saturation, Figure B is a diagram when it is demagnetized, and Figures 7 and 8 are convergence measurements of the color picture tube of the present invention. FIG. 3 is a diagram showing the configuration of the device. 11, 20...Color picture tube, 12...Convergence adjustment magnet, 22...Magnetic material, 1
5'...zoom lens, 16...detection device, 17
... Signal processing device, 18 ... Control device, 41, 4
3, 51, 53... Pulley, 42, 52... Pulse motor.

Claims (1)

[Claims] 1. Adjusting the convergence of an in-line color picture tube in which a convergence adjustment magnet is rotatably attached to the outside of the net, or an in-line color picture tube in which a convergence adjustment magnetic body is disposed inside the net. A convergence measuring device for measuring the convergence, which includes a drive device for moving the convergence adjustment magnet or a magnetization device for magnetizing the convergence adjustment magnetic body, and a variable magnification device disposed opposite to the screen of the color picture tube. zoom lens and
a magnification changing device that changes the magnification of the zoom lens; a detection device that detects a pattern projected on the screen via the zoom lens; and a signal processing device that processes a detection signal from the detection device;
A control signal for adjusting convergence is sent to the driving device or the magnetizing device according to the signal from the signal processing device, and the magnification of the zoom lens is changed to a magnification that matches the control pulse to the magnification changing device. A convergence measurement device characterized by comprising a control device that sends out a magnification change signal.