JPH01204332A - Measuring device for landing characteristics of color picture tube - Google Patents

Abstract

PURPOSE:To make it possible to quickly measure the clearance of electron beam to other color phosphors of a color picture tube in high accuracy by measuring the current of a subdeflection magnetic field generated to displace the electron beam so as that the electron beam is incident to the corresponding color phosphor and to adjacent color phosphors in the phosphor mosaic of the tube with a specified ratio. CONSTITUTION:Main deflection means 21, 23, and a subdeflection coil 22 and a subdeflection current generating means 25 for micro-displacement of the electron beam on the phosphor screen are provided on a measuring device. Photodetection means 41R, 41G, 41B for detecting the luminosity of the phosphor screen, and a dividing means 60 for calculating the level ratio of the detected outputs of these photodetection means, and a control means 70 for controlling the subdeflection current generating means so as that the said calculated level ratio is made to a specified value are also provided on the device. The landing characteristics of the electron beam is measured basing on the subdeflection current which makes the level ratio to the specified value. Thereby the beam clearance to other phosphors of a color picture tube can be quickly measured in high accuracy.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A. Field of industrial application B. Overview of the invention C. Prior art D. Problem to be solved by the invention E. Means for solving the problem (Fig. 1) F. Effect G. Example G1. Structure of the example (Fig. 1) Operation of the G2 Embodiment (FIGS. 1 to 4) Effects of the Invention A Industrial Application Field The present invention relates to a landing characteristic measuring device for a color picture tube having a color selection mechanism.

B. Summary of the Invention The present invention provides a landing characteristic measuring device for a color picture tube, in which an electron beam has a phosphor mosaic of a corresponding color;
By generating a sub-deflection magnetic field and deflecting the electron beam so that it is incident on the adjacent phosphor mosaic of other colors at a predetermined ratio, based on the sub-deflection current value at this time, This allows the other color tolerance of an electron beam to be measured quickly and with high accuracy.

C. Conventional Technology As is well known, current color picture tubes produce red, red, It is designed to generate three colors of light: green and blue.

In a color picture tube, the alignment of the centers of the phosphor mosaic and the electron beam that irradiates it is an important condition in order to obtain a bright screen with correct colors, but there are various problems during the manufacturing process and operation. Depending on the cause, the two do not necessarily match. A state in which the center of the electron beam and the phosphor mosaic are deviated is called mislanding, and it is important to accurately and quickly measure this amount in manufacturing, quality assurance, etc. of color picture tubes. Such a device for measuring the amount of mislanding is disclosed in, for example, Japanese Patent Publication No. 57-10632.
It is disclosed in the publication No.

First, a conventional color picture tube landing characteristic measuring device will be described with reference to FIGS. 5 to 7.

An example of the configuration of a conventional landing characteristic measuring device is shown in FIG.

In FIG. 5, (10) shows the color picture tube as a whole, and three electron beams (11) are emitted from the electron gun (11).
2R), (12G) and (12B) are color-selecting mechanisms (such as aperture grills or shadow masks).
Through the slit or hole 13), the fluorescent mosaic of red, green, and two primary colors that constitute the fluorescent surface (14) is irradiated to emit light.

A main deflection coil (2) is installed at the neck of the color picture tube (10).
1) and a sub-deflection coil (22) are installed. The output of the deflection circuit (23) is supplied to the main deflection coil (21), and from this deflection circuit (23), a vertical synchronizing signal (■) as shown in FIG. 6A is supplied to the square wave generation circuit (24). The output of the square wave generating circuit (24) as shown in Figure B and the positive and negative outputs of the variable DC power supply (25) are supplied to the sub-deflection coil (22). is a bidirectional ammeter.

As a result, three electron beams (12R), (12G
) and (12B) have a fluorescent surface (14
) is deflected to scan the entire area, and microscopically oscillates near each phosphor mosaic.

The color switching circuit (27) is connected to the electron gun (
11), three electron beams (12R),
(12G).

(12B) Any one of them to be measured,
For example, the current amount of the green electron beam (12G) is set to a predetermined value, and the amount of current of the other two electron beams (12R) is set to a predetermined value.
and (12B) are blocked.

As a result, the fluorescent surface (14) of the color picture tube (lO) emits green light, and the green electron beam (12G)
As shown in Figure A, an arbitrary green phosphor mosaic (15), e.g.
G>, X
Areas symmetrically shifted by △X on the axis (1
7) and (18).

As shown in the figure, the centers (15c) and (16c) of the phosphor mosaic (15G) and the beam incidence area (16) in the absence of the sub-deflection magnetic field are shifted by Δd, that is, Since the mislanding amount of this phosphor mosaic (15G) in the X direction is △d, the areas where the left and right beam incidence areas (17) and (18) overlap with the phosphor mosaic (15G) are different. ,
As shown in the light output characteristic curve (19) in FIG. 7B, the light outputs , , 7 and LI 118 corresponding to each of the beam incident areas (17) and (18) are different.

From this FIG. 7, each beam incidence area (16) ~
While maintaining the relative positional relationship of (18), align the center (16c) of the central beam incidence area (16) with the center (15c) of the phosphor mosaic (15G) to make the amount of mislanding zero. , it is easy to understand that the light outputs corresponding to the beam radiation areas (17) and (18) on both sides are equal.

In other words, if the electron beam is oscillated symmetrically with respect to the emission center in the mislanding state, and both oscillating beam incident areas are deviated by the same amount in the same direction so that the corresponding optical outputs are equal, then this amount of deviation is Δd is the amount of mislanding required.

Therefore, in the conventional device shown in Fig. 5, the color picture tube (
A light receiver (31) is placed in front of a predetermined measurement area of the fluorescent surface 14) of 10), and the color filter (32) and the photoelectric conversion element (33) such as a photodiode are used to The optical output based on such a swinging electron beam is converted into an electrical signal. Generally, the electron beam mislandes on the phosphor mosaic, so as shown in Figure 6C, the output signal ◎ of the photoreceiver (32) at the start of measurement is a pulse with the same level every other field. and is displayed on a display device (34) such as an onroscope.

While observing the waveform of this oscilloscope (34), the measurer adjusts the voltage of the DC power supply (25) so that the height of each pulse is equal, and uses the ammeter (26) to adjust the voltage of the DC power supply (25) so that the height of each pulse is equal.
25) Read the output current I.

This output current 1 and the amount of deflection △d caused by the sub-deflection coil (22)' are calculated as follows: △d=KI when the sub-deflection angle is minute, K is a comparison constant. ), so if K is calibrated first, the amount of misland ink can be found from equation ( ]).

In addition, in the conventional device, as shown in Figure 6 and E, each pulse of the odd field and even field is separated and supplied to a zero output detection circuit (differential amplifier) in place of an oscilloscope, and this detection output is is supplied to a control device (35) such as a servo motor, and this control device (35)
By controlling the output of the DC power supply (25), automation of the measurement becomes possible.

D. Problems to be Solved by the Invention By the way, when a color picture tube is shipped with a deflection yoke attached in advance, it is difficult to guarantee or manage its quality.
The most important landing characteristic is the amount of mislanding that the electron beam can tolerate without damaging adjacent phosphor mosaics, that is, the tolerance for other colors.

However, although the conventional landing characteristic measuring device as described above can easily measure the amount of mislanding, it is not suitable for measuring other color latitude.

Therefore, when measuring the other color latitude, observation using an optical microscope is required, which is complicated and takes a long time, and it is difficult to measure with high precision.

Alternatively, the measurement result of the amount of mislanding as described above may be used as a substitute, but since the actual dimensions and arrangement pitch of the phosphor mosaic vary from the design standard values, it does not necessarily correspond to other color tolerances and may result in high There was a problem that accuracy could not be obtained.

In view of the above, an object of the present invention is to provide a landing characteristic measuring device that can quickly and accurately measure the other color latitude of a color picture tube.

E Means for Solving the Problems The present invention provides a main deflection means (main deflection means) for deflecting the electron beam of a color picture tube having a color selection mechanism over the entire fluorescent surface.
21), (23), and a color picture tube landing characteristic measuring device comprising a sub-deflection coil (22) and a sub-deflection current generating means (25) for minutely deflecting an electron beam on a fluorescent surface. There are a plurality of light detection means (41R) and (41G) for detecting light emission from the fluorescent surface.

(41B), a dividing means (60) for calculating the level ratio of the detection outputs of the plurality of light detecting means, and a sub-deflection current generating means so that the level ratio calculated by the dividing means becomes a predetermined value. A control means (70) for controlling the sub-deflection current value I22. when the level ratio is a predetermined value. This is a landing characteristic measuring device for a color picture tube, which measures the landing characteristic of an electron beam based on the following.

F Effect: According to this configuration, the mislanding margin for other colors of the electron beam can be measured quickly and with high precision.

G. Embodiment Hereinafter, an embodiment of the landing characteristic measuring device for a color picture tube according to the present invention will be described with reference to FIGS. 1 to 4.

G1 Structure of Embodiment FIG. 1 shows the structure of an embodiment of the present invention. In FIG. 1, parts corresponding to those in FIG. 5 are given the same reference numerals and redundant explanation will be omitted.

In FIG. 1, the fluorescent surface (14) of the color picture tube (10) is shown.
) facing the three light receivers (41R), (41G) and (41) corresponding to the three primary colors of red, green and blue, respectively.
B) is provided. This receiver consists of small diameter color filters (42R), (42G), (42B) and photodiodes (43R), (43G), (43B), respectively.
) and are preferably arranged close to each other and close to the front surface of the color picture tube (10).

Receiver (41R), (41G) and (41B)
The outputs of are the amplifiers (44R) and (44G), respectively.
and (44B)), the peak hold circuit (
45R), (45G) and (45B).

(50) is a crosstalk removal circuit, and in the embodiment shown in FIG. It is provided to remove crosstalk and mainly consists of subtracters (51) and (52) and variable resistors (53) and (54) connected in series therebetween.

Peak hold circuit (45R) and (45B>
The outputs of the peak hold circuit (45G) are supplied to the subtracters (51) and (52), respectively, and the output of the peak hold circuit (45G) is supplied to the connection midpoint (input terminal) (55) of the variable resistors (53) and (54). The outputs of both subtractors (51) and (52) are supplied to the p-side and p-side fixed contacts of the changeover switch (56), respectively.

Reference numeral (60) denotes a divider circuit, which is composed of logarithmic amplifiers (61) and (62) and a subtracter (63). The output of the peak hold circuit (45G) is supplied to one logarithmic amplifier (61) via the input terminal (55) of the crosstalk removal circuit (50), and the switch (56)
The output of the logarithmic amplifier (62) is supplied to the other logarithmic amplifier (62), and the output of the other logarithmic amplifier (62) is subtracted from the output of the one logarithmic amplifier (61) in the subtracter (63). ) and (62) are obtained.

The output of the division circuit (60) is sent to the comparator (
The voltage is supplied to one input terminal of a differential amplifier (71) and compared with a reference voltage V r e f of a voltage source (72) connected to the other input terminal. The output of the comparator (71) is sent to the selector switch (
The output of the switch (74) is supplied to the n-side fixed contact of the switch (74) and directly to the p-side fixed contact of the switch (74) as a control signal. The positive and negative polarity outputs of this DC type #1 (25) are supplied to the sub-deflection coil (22) via a bisonal ammeter (26), and a closed loop including the color picture tube (10) is formed. It is formed.

G2 Operation of the Embodiment Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to FIGS. 2 and 3.

In this example, the color picture tube (10
) is equipped with an aperture grill as a color selection mechanism (13), and correspondingly, a three-color phosphor mosaic (15R)
, (15G) and (15B) form a stripe shape as shown in FIG. Furthermore, the cross section of the electron beam that passes through the aperture grill becomes approximately rectangular.

First, the walking direction (negative direction) of the green electron beam (12G)
The other color latitude is to be measured, and the spindles 56) and (74) are connected as shown. Forward direction (positive direction)
When measuring other color tolerances, switch (56) and (
74) is switched to a connection state opposite to that shown.

First, the color switching circuit (27) switches the green electron beam (
The current amount of red and blue electron beams (12R) and (12B) is set to a predetermined value.
is shut off and measurement begins.

As shown in FIG. 3A, at the opening time t, the value of the sub-deflection current I22 flowing through the coil (22) is zero, and the green beam (12G) is directed to a predetermined position on the fluorescent surface (14). The light is incident on an arbitrary green stripe (15G) at the measurement position.

As shown in Figure 2A, the first beam incidence area (16)
The center (16c) is a green stripe (15G)
Although it is in a mislanding state shifted by Δd from the center (15c) of , it does not invade the adjacent red and blue stripes (15R) and (15B).

Therefore, the fluorescent surface (14) of the color picture tube (10) emits green light, and this green light passes through the green filter (42G) of the light receiver (41G) and is transmitted to the photodiode (42G).
3G), the receiver (41R) and (
Although the light is attenuated by the red and blue filters (42R) and (42B) of 41B), it reaches the photodiodes (43R) and (43B>, respectively).

The detection output of the normal light of the photoreceiver (41G) is detected by the amplifier (
44G) and the peak hold circuit (45G) to the input terminal (5
5), and the light receiver (41R) and (
The detection output of the losstalk light of 41B) is transmitted through amplifiers (44R) and (44B) and peak hold circuits (45R) and (45B), respectively.
It is supplied to attenuators (51) and (52).

The variable resistors (53) and (54) are adjusted appropriately,
The detection output of the normal light whose level has been reduced is the output of both subdividers (51)
and (52), the detection outputs of the crosstalk light are canceled out, and the outputs of both the subtractors (51) and (52) become minute.

The minute output of the subtracter (51) or (52) is selected by a switch (56) and supplied to the other logarithmic amplifier (62) of the divider circuit (60). One logarithmic amplifier (6
1) is supplied with the normal light detection output from the terminal (55), and as shown in Figure 3, the initial value of the output V60 of the divider circuit (60) is positive and large V a S becomes.

In the comparator (71), the initial output voltage V a s of this divider circuit (60) and the reference voltage V r of the power supply (72)
@r is compared, and the initial output of the comparator (71) also becomes a large positive value, which is inverted by the inverter (73). This causes the output V, of the control port (70), as shown in FIG. 3C. The initial value of is negative polarity and large V
b s, the initial output voltage V b s of this control circuit (70) is supplied to the variable DC power supply (25), and the third
As shown in the figure, □Output current I2 of the DC power supply (25)
2 increases in the negative direction, and the intermediate time point 1. Its value becomes II.

The electron beam (12G) is deflected to the left by the auxiliary deflection magnetic field generated when this current 11 flows through the coil (22), and as shown in FIG.
However, the red stripe (15R) and the green stripe (15R)
G) For example, let us assume that you straddle the same area. At this time, since the photodetection outputs of the photodetectors (41R) and (41G) are equal, the output voltage of the divider circuit (60) becomes zero, and the output voltage of the control circuit (70) is V. corresponds to the negative reference voltage C-vrer), which has a positive polarity and has an intermediate value Vbl which is smaller than the initial absolute value 1vb,l (FIG. 3B, C).

The output voltage vbt of this control circuit (70) is supplied to an appropriately offset variable power supply (25), and as shown in FIG.
As shown in the figure, the value of the sub-deflection current I22 is controlled to be small.

In this embodiment, the reference voltage V r of the power supply (72)
f is the optical output of the measured green beam (12G) slightly incident on the red or blue stripe (15R) or (15B) and the green beam (15G)
The control loop is set to be balanced when the ratio of the light output to the light output becomes, for example, 1:100.

As a result, the values of the sub-deflection current I22, the outputs V60 and v i o of the divider circuit (60) and control circuit (70) are as follows.
As shown in FIG. 3, after the above-mentioned time ti, it changes in a damped oscillatory manner, and at the loop equilibrium time t, it converges to Vref and zero, respectively. At this time, the incident area (17f) of the green beam (12G) slightly invades the red stripe (15R), as shown in FIG. 2C.

Then, the value ■22 of the sub-deflection current I22 at time t.
f is read with an ammeter (26), and the initial beam incidence area (
16), the amount of deviation Δ× of the beam incident area (17f) is determined according to the above equation (1), and this is taken as the other-color tolerance in the walking direction.

The other color tolerance ΔXB in the forward direction as shown in the second diagram is obtained in the same manner as described above by switching the switch 56) and the gate 74) to the opposite connection state from that shown.

Although the measurement of the other color tolerance of the green electron beam according to this embodiment has been described above, in reality, it is necessary to also measure the other color tolerance of the red and blue electron beams.

For this reason, for example, as shown in FIG.
7), three color receivers (41R), (41G)
.

The switching circuit (80) that switches the photodetection output of (41B) according to the beam to be measured is a crosstalk removal circuit 5.
0), and also within the crosstalk removal circuit (50), a pair of variable resistors (53R), (54R), etc. are switched depending on the beam to be measured, and the level of the canceling signal is changed. can be switched.

According to this embodiment, the other color latitudes of the three-color electron beam in the positive and negative directions can be measured with high precision per measurement position in a short period of time, for example, about 1 second.

Although the embodiment shown in FIG. 1 employs analog circuits, the divider circuit (60) and control circuit (70), including the variable DC power supply (25) and ammeter (26), are digitally operated. It can be replaced with a circuit.

H Effects of the Invention As detailed above, according to the present invention, an electron beam is incident on a phosphor mosaic of a corresponding color and an adjacent phosphor mosaic of another color at a predetermined ratio. In this way, the electron beam is deflected by generating a sub-deflection magnetic field, so the color picture tube can quickly and accurately measure the other color tolerance of the electron beam based on the sub-deflection current value at this time. A landing characteristic measuring device is obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of a color picture tube landing characteristic measuring device according to the present invention, and FIGS. 2 and 3 are route diagrams and route diagrams for explaining the operation of the embodiment shown in FIG. 4 is a block diagram showing the configuration of essential parts of an embodiment of the present invention, FIG. 5 is a block diagram showing an example of the configuration of a conventional color picture tube landing characteristic measuring device, and FIGS. Figure 7 is a time chart and route map for explaining the operation of the conventional example. (10) is a color picture tube, <12R), (12G),
(12B) is an electron beam, (21) is a main deflection coil, (22) is a sub-deflection coil, (25) is a variable DC power supply, (26) is an ammeter, and (41R). (41G), (41B) are light receivers, (50) are crosstalk removal circuits, (60) are division circuits, (71) are comparators, ①, 8. is the reference voltage. Agent Mamukai Ito
Matsukuma Hide Morinaka ￥ Gu- g ward If' elJ Kitozu row 5 Sakurai-Iwo°1ri Yubutsu Keyato 6 Figure 15Q: Dimensions of the treasure body 7G, /'7.18: Electric) Yumu incident nod taste (fl coming 4
Te'lq Lunch°゛Inf'' (missing boil, Figure 7)

Claims (1)

[Scope of Claims] A main deflection means for deflecting an electron beam of a color picture tube having a color selection mechanism over the entire phosphor surface, and a sub-deflection means for slightly deflecting the electron beam on the phosphor surface. A landing characteristic measuring device for a color picture tube, comprising a coil and a sub-deflection current generating means, comprising a plurality of light detection means for detecting light emission from the fluorescent surface, and a level of detection output of the plurality of light detection means. a dividing means for calculating the ratio; and a control means for controlling the sub-deflection current generating means so that the level ratio calculated by the dividing means becomes a predetermined value; A landing characteristic measuring device for a color picture tube, characterized in that the landing characteristic of the electron beam is measured based on a sub-deflection current value.