JPH02214393A - Check device for automatic degaussing circuit - Google Patents

Abstract

PURPOSE:To improve the reliability of decision by deciding defect depending on the initial level of a degaussing signal, a degaussing time and a degaussing characteristic data corresponding to the degaussing characteristic in response to the attenuation state of the degaussing detected by a detection sensor. CONSTITUTION:A check section 3 uses an initial level arithmetic means 10 to calculate a mean value of a peak level at the initial point of time of a degaussing signal from a magnetic field detection sensor 4 inputted via an output section 5 and to calculate the initial level. A degaussing time measuring means 11 measures the degaussing time till the degaussing signal is inputted and attenuated. A degaussing characteristic data calculation means 12 multiplies each peak level with a prescribed period and adds the products sequentially, and the resulting data is divided with a data being the product between a reference initial level and a reference degaussing time set in a parameter setting section 7 to calculate the degaussing characteristic data. A deciding means 16 decides the circuit to be nondefective when the initial level is the reference initial level or below, the degaussing time is the reference degaussing time or below and the degaussing characteristic data is the reference degaussing characteristic data or over based on the outputs of the comparator circuits 13-15 and decides the circuit to be defective in other cases and gives the decision output to a display section 6.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an automatic demagnetizing device configured to automatically demagnetize a shadow mask, etc. of a color picture tube by a demagnetizing coil to which an alternating current demagnetizing current is applied. The present invention relates to an apparatus for inspecting the circuit state of the automatic degaussing circuit in a color television receiver equipped with the circuit.

<Prior art> When a shadow mask built into a color picture tube is magnetized, the trajectory of the electron beam emitted from the three-color electron system of the color picture tube is affected by the magnetization and changes the trajectory of the shadow mask. Irregularly bent in parts. It is known that when the trajectory of the electron beam is bent in this way, the electron beam cannot correctly irradiate the red, blue, and green phosphors, causing a so-called color shift phenomenon. .

In order to eliminate such color shift phenomenon, color television receivers are usually equipped with a degaussing coil around the color picture tube, and when the color television receiver is turned on, the degaussing coil is An automatic demagnetization circuit is provided that automatically demagnetizes the shadow mask by passing a current through it.

By the way, when inspecting the circuit condition of such an automatic degaussing circuit, it is necessary to check the state of the color picture tube at the time when the circuit chip constituting the automatic degaussing circuit, including the degaussing coil, is removed from the color television receiver on the inspection line. There are inspection methods that check the operating state of the automatic degaussing circuit by comparing the static state of the image on the tube surface and the shaking state of the image when the circuit chip is attached, or the external state of the color picture tube. There is an inspection method in which the shadow mask is forcibly magnetized to cause a color shift phenomenon, and the operating status of the automatic degaussing circuit is confirmed by removing the color shift with the circuit chip attached. It was getting worse.

However, with either inspection method, the slight degaussing operation is performed depending on the visual judgment of the operator, so when inspecting a large number of color television receivers on the inspection line, However, it is unavoidable that many inspection errors may occur even by skilled workers, and the reliability of inspections has not always been high.

Therefore, in the patent application "Inspection device for automatic degaussing circuit" filed on May 19, 1988, the applicant proposed an inspection device that can automatically and highly reliably test the operating state of an automatic degaussing circuit. is suggesting.

<Problems to be Solved by the Invention> In the above optical application, the attenuation rate is calculated as follows from the demagnetization signal corresponding to the demagnetization attenuation state obtained by processing the output of the sensor that detects the demagnetization operation. The authors have proposed an inspection device that determines whether the operating state of an automatic degaussing circuit is good or bad by comparing the damping ratio and damping ratio with a reference damping ratio and a reference damping ratio. In other words, the attenuation rate is determined by dividing the difference between the average value of the magnitude of the degaussing signal within a predetermined period from the start of the test and the average value of the magnitude of the degaussing signal within the predetermined period before the end of the test by one of the average values. The damping ratio is obtained by dividing the difference in the magnitude of the degaussing signal between two times by the difference in the magnitude of the degaussing signal between the other two times.

The present invention relates to the improvement of such an inspection device, and aims to provide a more reliable inspection device, in particular, to be able to make accurate judgments even when the degaussing time is extremely long or short. do.

Means for Solving the Problems> In order to achieve the above object, the inspection device of the present invention has the following features:
a detection sensor that detects a demagnetization operation in a shadow mask or the like of a color picture tube; an output unit that processes the output of the detection sensor and outputs a demagnetization signal according to a demagnetization attenuation state;
an inspection section that determines whether the circuit state of the automatic degaussing circuit is good or bad based on the degaussing signal; and a test section that determines whether the circuit state of the automatic degaussing circuit is good or bad based on the output of the inspection section. and a display section for displaying whether the degaussing signal is detected, and the inspection section includes: peak level detection means for detecting the peak level of the degaussing signal every predetermined period; and calculating an average value of the peak level at the start of degaussing. an initial level calculating means for calculating an initial level; a demagnetizing time measuring means for measuring a demagnetizing time from when the demagnetizing signal is input until it decays; demagnetizing characteristic data calculation means for calculating demagnetizing characteristic data corresponding to the demagnetizing characteristic by dividing the data sequentially added by the data obtained by multiplying the reference initial level and the standard demagnetizing time set in advance; initial level comparison means that compares the level with the reference initial level and provides a corresponding output; demagnetization time comparison means that compares the demagnetization time with the reference demagnetization time and provides a corresponding output; and the demagnetization characteristic data. and a demagnetizing characteristic data comparing means for comparing the demagnetizing characteristic data with preset reference demagnetizing characteristic data and outputting a corresponding output, based on the outputs of the initial level comparing means, the demagnetizing time comparing means, and the demagnetizing characteristic data comparing means. , and determining means for determining whether the circuit state of the automatic degaussing circuit is good or bad.

<Operation> According to the above configuration, the output section outputs a demagnetizing signal according to the attenuation state of the degaussing operation detected by the detection sensor,
The inspection section determines whether the circuit condition of the automatic degaussing circuit is good or bad based on this degaussing signal, and the judgment result of this inspection section is displayed on the display section. Therefore, if you look at the display on the display section, , the circuit status of the automatic degaussing circuit can be known.

Moreover, since the inspection section determines whether the circuit condition is good or bad based on the initial level of the degaussing signal, the degaussing time, and the demagnetizing characteristic data corresponding to the demagnetizing characteristic, the testing device proposed in the above-mentioned optical application, that is, the attenuation Compared to systems that judge good/bad based on ratio and attenuation rate, it is more reliable and accurate judgment can be made especially when the demagnetization time is long or extremely short. .

<Examples> Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram of an embodiment of the present invention. In the figure, 1 is a color television receiver equipped with an automatic degaussing circuit, and 2 is a remote control signal for turning on the color television receiver l in response to a control signal from an inspection section 3, which will be described later. It is a remote control transmitter, and when the power of the color television receiver 1 is turned on, the automatic degaussing circuit is configured to automatically perform a degaussing operation.

The automatic degaussing circuit inspection device of this embodiment includes a magnetic field detection sensor 4 that detects a strong magnetic field component of a color picture tube during degaussing operation and converts it into a voltage signal;
an output unit 5 that processes the output of the output as described below and outputs a demagnetization signal according to the demagnetization attenuation state, and based on the demagnetization signal,
Inspection section 3 that determines whether the circuit condition of the automatic degaussing circuit is good or bad
and a display section 6 that displays whether the circuit state of the automatic degaussing circuit is good or bad based on the output of the inspection section 3. Note that 7 is a parameter setting section for setting data, etc. as a criterion for determination in the inspection section 3.

The output unit 5 that processes the output of the magnetic field detection sensor 4 to form a demagnetizing signal includes an amplifier that amplifies the output of the magnetic field detection sensor 4, a low-pass filter to which the output of this amplifier is given, and an output unit that outputs the output of the low-pass filter into the aftermath. It is equipped with an aftereffect rectifier circuit that performs rectification and a peak hold circuit that peak-holds the output of this aftereffect rectifier circuit.
A).

A degaussing signal as shown in (B) is output to the inspection section 3.

The inspection section 3, which determines whether the circuit state of the automatic degaussing circuit is good or bad based on the degaussing signal, is composed of an A/D conversion circuit, a microcomputer, and the like.

FIG. 2 is a functional block diagram of this inspection section 3. The inspection unit 3 includes a peak level detection means 8 for detecting the peak level of the demagnetization signal at each predetermined period as shown in FIG. an initial level calculating means 10 for calculating an initial level (initial voltage) which is the average value of the peak level of the demagnetizing signal at , a demagnetizing time measuring means 11 for measuring the demagnetizing time until the demagnetizing signal attenuates, and a demagnetizing characteristic. A demagnetizing characteristic data calculation means that calculates demagnetizing characteristic data corresponding to! 2
and an initial level comparing means 1 which compares the initial level with a preset reference initial level and provides a corresponding output.
3, a demagnetizing time comparing means I4 which compares the demagnetizing time and a reference demagnetizing time and provides a corresponding output, and a demagnetizing device which compares the demagnetizing characteristic data with preset reference demagnetizing characteristic data and provides a corresponding output. It includes a characteristic data comparing means 15 and a determining means 16 for determining whether the circuit condition of the automatic degaussing circuit is good or bad based on the outputs of the respective comparing means t3, 14, and 15.

The initial level calculating means 10 calculates the average value of the peak levels of the degaussing signal at the initial point in time, for example, five peak levels P1, as shown in FIG. 3(A). P2. P3.
P4. The initial level is calculated by calculating the average value of P5.

The demagnetization time measuring means 11 measures the demagnetization time from when the demagnetization signal is input until it is attenuated, for example, the time t in FIG. 3(B).

The demagnetizing characteristic data calculation means I2 divides the data obtained by multiplying each peak level by a predetermined period and adding them sequentially by the data obtained by multiplying the reference initial level and reference demagnetizing time set in advance by the parameter setting section 7. By this,
Calculate demagnetizing characteristic data corresponding to the demagnetizing characteristic. The degaussing characteristic data calculating means 12 uses the data obtained by multiplying each detected peak level by a predetermined time and adding them sequentially, that is, the stepwise area S2 in FIG. 3(C), to the reference initial level Vl and the reference Demagnetization time t! , that is, divided by the area S1 of the rectangle in FIG. 3(C), and further multiplied by 100 to obtain demagnetization characteristic data.

The determining means 16, which determines whether the circuit state of the automatic degaussing circuit is good or bad based on the outputs of the respective comparing means 13, 14, 15, determines that the initial level is below the reference initial level, the demagnetizing time is below the reference demagnetizing time, Further, when the demagnetizing characteristic data is equal to or greater than the reference demagnetizing characteristic data, it is determined that the circuit condition is good; otherwise, it is determined that the circuit condition is defective, and the determination output is provided to the display section 6.

As a result, the display section 6 displays whether the circuit state of the automatic degaussing circuit is good or bad.

In this way, the circuit state of the automatic degaussing circuit can be known just by looking at the display on the display unit 6, and more accurate inspection than conventional visual judgment is possible.

Furthermore, the inspection section 3 determines whether the circuit condition is good or bad.
Since this is performed using the initial level of the demagnetizing signal, the demagnetizing time, and the demagnetizing characteristic data corresponding to the demagnetizing characteristic, it is more reliable than the method previously proposed by the applicant in which the determination of good/bad is made based on the damping ratio and damping rate. Accurate determination can be made even when the degaussing time is extremely long or short. In other words, with the previously proposed inspection device, the degaussing time may be judged as normal even if it is abnormally long, or the degaussing time may be short (which would result in poor reliability) because the average value of multiple points is used. With the inspection device of this embodiment, such a problem does not occur.

Further, in this embodiment, the respective data obtained by the initial level calculating means 10, the demagnetizing time measuring means 11, and the demagnetizing characteristic data calculating means 12 are also sequentially given to the display section 6 and displayed at each inspection. It has become. therefore,
Based on these displayed data, it is also possible to easily modify the reference data set from the parameter setting section 7.

<Effects of the Invention> As described above, according to the present invention, the output unit outputs a degaussing signal according to the attenuation state of the degaussing operation detected by the detection sensor, and the inspection unit outputs a degaussing signal based on this degaussing signal. , determines whether the circuit condition of the automatic degaussing circuit is good or bad, and displays the judgment result of this inspection section on the display section, so you can know the circuit condition of the automatic degaussing circuit by looking at the display on the display section. It is possible to make a more accurate determination than in the conventional example where the determination is made using the following method.

Furthermore, the inspection department uses the initial level of the degaussing signal, degaussing time, and degaussing characteristic data corresponding to the degaussing characteristics to determine whether the circuit condition is good or bad. Even in such cases, accurate judgments will be made.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG.
FIG. 3 is a functional block diagram of the inspection section shown in the figure, and FIG. 3 is a signal waveform diagram for explaining the operation. 3... Inspection section, 4... Magnetic field detection sensor, 5... Output section, 6... Display section.

Claims (1)

[Claims] (1) A device for inspecting the circuit state of the automatic degaussing circuit of a color television receiver equipped with an automatic degaussing circuit, which comprises a detection sensor for detecting degaussing operation in a shadow mask or the like of a color picture tube; an output section that processes the output and outputs a demagnetization signal according to a demagnetization attenuation state; an inspection section that determines whether the circuit state of the automatic degaussing circuit is good or bad based on the demagnetization signal; and a display section that displays whether the circuit state of the automatic degaussing circuit is good or bad based on the output, and the inspection section detects the peak level of the degaussing signal every predetermined period. peak level detection means; initial level calculation means for calculating an initial level by calculating an average value of the peak level at the time of starting demagnetization; and measuring demagnetization time from when the demagnetization signal is input until it attenuates. The degaussing characteristic is determined by using a degaussing time measuring means and dividing the data obtained by multiplying each of the peak levels and the predetermined period and sequentially adding them by the data obtained by multiplying the reference initial level and the reference demagnetizing time set in advance. a demagnetizing characteristic data calculating means for calculating demagnetizing characteristic data corresponding to the demagnetizing characteristic data; an initial level comparing means for comparing the initial level and the reference initial level to provide a corresponding output; and calculating the demagnetizing characteristic data corresponding to the demagnetizing time and the reference demagnetizing time. demagnetizing time comparison means for comparing and providing a corresponding output; demagnetizing characteristic data comparing means for comparing the demagnetizing characteristic data and preset reference demagnetizing characteristic data and providing a corresponding output; and the initial level comparing means. An inspection device for an automatic degaussing circuit, comprising: a determining means for determining whether the circuit state of the automatic degaussing circuit is good or bad based on the degaussing time comparison means and the demagnetization characteristic data comparison means and the output.