JPH0738294B2 - Electron beam adjusting device for cathode ray tube - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electron beam adjusting device for a cathode ray tube, which adjusts the position of an electron beam with respect to the phosphor coated on the tube surface of the cathode ray tube.

[Conventional technology]

Conventionally, a cathode ray electron beam has been applied to the surface of the R
ITC adjustment is performed in order to properly irradiate each dot-shaped phosphor of (red), G (green), and B (blue). In ITC adjustment, a CP ring or deflection yoke composed of a magnet for color purity adjustment provided at the neck of the cathode ray tube, or a separately provided adjustment coil is used as the adjustment means for adjusting the position of the electron beam with respect to the phosphor. Has been. At present, the emission brightness of the phosphor is used as a criterion for determining whether or not the electron beam position-adjusted by such adjusting means strikes the phosphor correctly. That is, since the light emitting area of the phosphor and the brightness thereof are generally in a proportional relationship, the state where the electron beam hits the phosphor correctly when the brightness becomes maximum, that is, the center of the electron beam and the phosphor It is determined that the centers of the two match.

In Fig. 4, moving the deflection yoke and CP ring,
Alternatively, when the electron beam 2 ₁ is moved to the positions of the electron beams 2 ₂ and 2 ₃ with respect to the phosphor 1 by moving an adjustment coil to which a current is passed, the brightness of the phosphor 1 at the position of the electron beam 2 _2. If is the maximum, the position is set as the optimum position.

In FIG. 5, when the electron beam is moved in the + and-directions from the reference point 0 and the brightness for each point is obtained and a curve is drawn, the distance (movement amount) between the maximum brightness and the reference point 0 corresponds to the electron beam. The amount of deviation a from the phosphor.

[Problems to be Solved by the Invention]

Since the electron beam adjustment of the conventional cathode ray tube is performed as described above, in the current manufacturing technology of the cathode ray tube as a mass-produced product, all the phosphors of all the products or individual products have a uniform thickness. Is difficult to apply, and if other external factors or the like are added to this, the proportional relationship between the light emitting area of the phosphor and the brightness is broken. Therefore, as shown in FIG. 6, the position of the electron beam (light emitting area) is not proportional to the brightness, and therefore the position where the maximum brightness is simply obtained and the reference point 0
There is a problem that an error occurs from the true optimum position when the distance between and is the shift amount a.

The present invention has been made to solve the above problems, and corrects the collapse of the proportional relationship between the light emitting area of the phosphor and the luminance, and can obtain the correct optimum position and shift amount a. An object is to obtain an electron beam adjusting device for a cathode ray tube.

[Means for Solving the Problems]

The electron beam adjusting device for a cathode ray tube according to the present invention is R, G,
Adjusting means for moving the irradiation position of the electron beam on any one of the dot-shaped phosphor of B, and detection means for detecting a plurality of brightness values of the phosphor at a plurality of irradiation positions of the electron beam , A continuous approximation curve indicating the relationship between the brightness value and the position of the electron beam, which is approximate to the relationship between the plurality of brightness values obtained from the detecting means and the plurality of irradiation positions of the electron beam And calculating means for calculating the peak value of the brightness value of this approximate curve,
The position of the electron beam is made to coincide with the position of the electron beam corresponding to the peak value by the adjusting means.

[Action]

The electron beam adjusting apparatus for a cathode ray tube according to the present invention can obtain the electron beam at the optimum position by obtaining the peak value of the approximate curve and then adjusting the adjusting means so that the brightness reaches the peak value.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 3 is a cathode ray tube, 4 is a deflection yoke provided at the neck portion of the cathode ray tube 3, 5 is a CP ring provided at the neck portion of the cathode ray tube 3, and 6 is R, G on the tube surface of the cathode ray tube 3. , A drive circuit including a deflection circuit for outputting the raster of B, 7 is a camera for photographing the tube surface of the cathode ray tube 3 and measuring the brightness, 8 is an amplifier for amplifying the brightness signal obtained from the camera 7, and 9 is An A / D converter for converting the output signal of the amplifier 8 into a digital signal, 10 processes the digital signal obtained from the A / D converter 9 to obtain an approximate curve to be described later, and to calculate the peak value of the approximate curve. In this embodiment, an arithmetic circuit including a microcomputer is used as the arithmetic means to be obtained.
The camera 7, the amplifier 8 and the A / D converter 9 constitute a detecting means for detecting the brightness.

Next, the operation will be described. In the case of an ideal cathode ray tube in which all the phosphors are coated on the tube surface with a uniform thickness, the electron beam center and the phosphor center coincide with each other and the maximum brightness is obtained. Left and right beam (+,-direction)
When shaken, the luminance with respect to the amount of movement of the electron beam should change symmetrically. The present invention is based on the above concept, and detects a change in luminance with respect to the amount of movement of an electron beam, obtains an approximate curve thereof, and uses a peak value of the approximate curve as a correction value. That is, first, in FIG. 2, the brightness at each position of the electron beam is measured, and based on the characteristic A obtained by plotting this, a two-dimensional approximation curve B approximating the characteristic A is obtained. Next, the peak value of the peak point p of the approximate curve B is obtained and this is set as the optimum position of the electron beam.

The operation of FIG. 1 based on the above principle will be described with the flowchart of FIG. First, in step ST (1), the drive circuit 6 is operated to scan the electron beam of the cathode ray tube 3 on the tube surface, and the camera 7 measures the brightness which changes accordingly. The measured luminance signal is converted into a digital signal as data indicating a luminance value by the A / D converter 9 through the amplifier 8 in step ST (2). The processing in steps ST (1) and ST (2) is performed until the end of measurement is determined in step ST (3). During this time, the measured data is sent to the arithmetic circuit 10 and held together with the position of the electron beam. When the measurement is completed, the process proceeds to step ST (4), the approximation range and the data interval required for the approximation are input to the arithmetic circuit 10, and the measured data is plotted according to these to obtain the characteristic A. Next, a two-dimensional approximation curve B that approximates the characteristic A is calculated, and the peak value of the peak point p of this approximation curve B and the shift amount a are calculated.
And so on, and so on. Next, in step ST (5), the adjusting means is used to move the electron beam and adjust so that the brightness measured at this time matches the peak value. When it is detected in step ST (6) that the brightness matches the peak value, the process ends.

In the above embodiment, the case where the ITC adjustment of the cathode ray tube 3 is performed has been described, but the focus adjustment of the camera can be performed by changing the focal point of the light emitting body having a constant luminance and measuring the luminance. .

〔The invention's effect〕

As described above, according to the present invention, the relationship between the position of the electron beam and the brightness is formed as a curve approximated based on the actual measurement data, and the point at which the peak value of the approximated curve is obtained is the electron beam. Since it is configured to be the optimum position of, it is possible to correct the variation of the phosphor, external factors, etc., and also it is possible to perform adjustment with high accuracy and fast measurement speed with a small number of measurement data. is there.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electron beam adjusting device for a cathode ray tube according to an embodiment of the present invention, FIG. 2 is a graph diagram for explaining the principle of the device, and FIG. 3 is a diagram for explaining the operation of the device. FIG. 4 is a flowchart showing an electron beam and a phosphor for explaining an electron beam adjusting method for a conventional cathode ray tube, FIG. 5 is a graph for explaining the principle of the conventional adjusting method, and FIG. [Fig. 6] is a graph for explaining problems of the conventional adjustment method. 3 is a cathode ray tube, 4 is a deflection yoke, 5 is a CP ring, 7 is a camera, 8 is an amplifier, 9 is an A / D converter, and 10 is an arithmetic circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. Adjustment means for moving an irradiation position of an electron beam on one of R, G, B dot-shaped phosphors, and a plurality of the phosphors at a plurality of irradiation positions of the electron beam. Of the brightness value and the position of the electron beam approximated to the relationship based on the relationship between the plurality of brightness values obtained from the detection means and the plurality of irradiation positions of the electron beam. And a calculating means for obtaining a peak value of the brightness value of the approximate curve, and the adjusting means adjusts the position of the electron beam to the position of the electron beam corresponding to the peak value. An electron beam adjusting device for a cathode ray tube, characterized in that they are matched.