JPH05250990A - Back plate inspecting method for display device - Google Patents

Abstract

PURPOSE:To detect a defective part, and also heighten work efficiency by treating a pattern inspection on a back plate electrically in a back plate inspecting method for a display device where laterally symmetrical same electrodes are formed in multi-shape patterns. CONSTITUTION:Electrically conductive rubber 8 having a common electrode 7 is connected to plural electrodes 4 where patterns are formed on a back plate substrate 1, and false signals 10 are inputted to the common electrode of the equipotential electrically conductive rubber, and the signals transmitted through back plate patterns 4 are detected by means of a selecting circuit 12, a differential Amp circuit 13 and a comparing circuit 14 arranged in the rear stage. The detected result is displayed by means of a display element 15. Thereby, the detection of a failure place becomes possible, and inputs of the selecting circuit 12 are also switched by means of a counter circuit 17 in synchronism with a reference clock signal, so that an inspecting time can be shortened significantly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention electrically processes a continuity test of a back electrode pattern formed on a back electrode plate in a flat panel type display device used for a television receiver, a computer terminal display, etc. The present invention relates to an inspection method for inspecting the location detection and the quality determination.

[0002]

2. Description of the Related Art In recent years, electron tube type flat panel display devices have been actively developed. This flat panel display device is similar in principle to a display device using a conventional cathode ray tube (CRT), but the distance from the cathode to the anode is significantly shorter than that of the conventional CRT system, and the flat panel display device is thin. It realizes a display device. Therefore, the flat panel display device generally has a configuration in which a box-shaped hot cathode and an anode are housed.

Further, in order to actually control the electron beam, a back electrode in which left and right symmetrical patterns are arranged in a multi-shape is indispensable, and the back electrode pattern is superior to the flat panel display device. There is a demand for a performance that does not impair the performance and an inspection method that satisfies the performance.

A conventional method for inspecting a back electrode for a display device will be described below. FIG. 6 is an explanatory diagram of a conventional method for inspecting a back electrode for a display device. 1 is a back electrode substrate, 2,
3 is a control signal supply electrode for controlling the electron beam, 4 is a back electrode pattern, 5a and 5b are measuring probes, and 6 is a measuring instrument.

A method of inspecting the back electrode pattern 4 will be described below. Electrode 2 for electron beam control signal supply, which has a pattern formed on the surface of the back electrode substrate 1 and which has a symmetrical shape.
The measurement probe 5a and the measurement probe 5b are connected to the electrode 3 and the electrode 3, and the conduction state of the back electrode pattern 4 formed between the electrodes 2 and 3 is measured using a measuring device 6 (for example, a tester or a buzzer). By doing so, it is possible to determine a defect in the back electrode pattern 4.

[0006]

However, for example, the electrode pattern 4 used in a display device corresponding to 14 inches is used.
Then, the number of lines becomes about 100 lines, and it is necessary to inspect a pattern having that number of lines. As described above, the back electrode pattern 4 made up of a large number is inspected line by line, which requires a working time and is inefficient.

Further, since a continuity test is conducted by using a tester, a buzzer or the like as a test measuring instrument, it is difficult to confirm even if the back electrode pattern 4 is cracked, pinhole, short-circuited or the like. At the same time, since the inspection is performed by using the measurement probe, the electrode surface is scratched or soiled, and there is a problem in reliability.The present invention solves the above-mentioned conventional problems, and has the advantage of the flat panel display device. It is an object of the present invention to provide a method for inspecting a back electrode for a display device, which can satisfy the performance without impairing, improve the working efficiency, and improve the reliability.

[0008]

In order to solve the above-mentioned problems, the present invention provides a method for inspecting a back electrode for a display device, in which a pattern having the same symmetrical electrodes on the back electrode substrate is arranged in a multi-shape. That is, a conductive rubber having a common electrode is placed on one side of the pattern formed and arranged in the multi-shape, and after connecting the pattern and the conductive rubber,
An input signal detecting means for inputting a pseudo signal having a square wave or a sine wave to the common electrode portion of the conductive rubber and providing the pseudo input signal in the vicinity of a stylus (hereinafter referred to as a prober) configured on the other electrode. The method for inspecting a back electrode for a display device is characterized in that:

In this case, the input signal detecting means includes, for example, an input signal selecting circuit, a counter circuit for controlling the selecting circuit, a differential Am for detecting the input signal potential difference and the reference input signal.
The input signal detection circuit includes a comparison circuit that compares p with the differential Amp output signal, and a display element that displays the output signal of the comparison circuit.

[0010]

With this configuration, the plurality of electrodes patterned on the back electrode substrate are connected to the conductive rubber having a common electrode, and the common electrode of the conductive rubber having the same potential has a square wave or a sine wave. By inputting the pseudo signal, the pseudo signal is input to the selection circuit provided near the other-side electrode prober through the back electrode pattern.

The pseudo signal input to the selection circuit is
For the actual signal to transmit the back electrode pattern,
The length and width of the pattern affect the voltage drop.
For the voltage-dropped signal, after the potential difference between the actual signal and the voltage-dropped signal is detected by the differential Amp provided in the subsequent stage,
It is input to the comparison circuit configured in the next stage, and is detected as a signal component that is equal to or higher than the reference voltage set value. By displaying the detection results on a display element, it is possible to detect defects such as disconnections, cracks, and shorts that have occurred in the back electrode pattern, and since conductive rubber is used, scratches and stains on the electrode surface Generation can be suppressed and reliability can be improved.

Since the input switching of the selection circuit is digitally controlled by the counter circuit synchronized with the reference clock signal, it becomes possible to automatically select a plurality of electrodes, which improves the inspection work efficiency. it can.

Further, a BCD circuit having another signal system and a driver / decoder circuit are formed in the subsequent stage of the input signal selection circuit, and the output data thereof are supplied to the display element to detect the input setting state of the selector circuit. This makes it possible to measure the defective portion.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an inspection method according to an embodiment of the present invention. Reference numeral 7 is a common electrode, 8 is a conductive rubber forming the common electrode, 9 is a holding plate of the conductive rubber and the electrode, 10 is a pseudo signal, 11 is a prober for taking out the pseudo signal, and 12 is an input signal. Selection circuit for selection, 13 is differential A
An mp circuit, 14 is a comparison circuit, and 15 is a display element.

Next, the operation of the method of this embodiment will be described with reference to FIGS. First, a conductive rubber 8 having a material of Au, Ag, or carbon and a pressing plate 6 on which a common electrode 7 is formed on an electrode 2 in which a plurality of electrode patterns are symmetrically arranged on a back electrode substrate 1 are placed. As a result, the electrode 2 and the conductive rubber 8 are connected to each other by the weight of the pressing plate 9, and the multiple electrodes 2 can be made to have the same potential.

Since the electrode 2 is connected to the common electrode 7, when the pseudo signal 10 having a square wave or a sine wave is input from the common electrode 7, the pseudo signal 10 passes through the electrode 2 and the back electrode pattern 4 and then to the other side. Au, P connected to the side electrode 3
In the vicinity of the prober 11 having any one of the materials d, a selection circuit 12 including a semiconductor switch (multiplexer) is provided.
Entered in.

Since the signal input to the selection circuit 12 is transmitted through the back electrode pattern 4, a voltage drop occurs between both ends of the electrodes 2 and 3 in proportion to the length and width of the back electrode pattern 4. (For example, if a crack or a pinhole is generated on the pattern surface, the pattern resistance decreases with a decrease in the pattern width, and the pattern resistance increases with respect to a short circuit between adjacent parts, so that signals are not supplied together in a disconnected state.) Pseudo-signal 1 with transmitted signal and source signal
By inputting 0 and 0 to the differential Amp 13 provided in the subsequent stage, the potential difference between the actual signal and the transmission system can be detected. R1 to R4 are high-precision matching resistors in consideration of the stability of the differential Amp13.

The output signal detected by the differential Amp 13 is
As shown in Fig. 2, E1 is the measurement input signal and E is the reference input signal.
Assuming that the output signal Aout has a larger potential difference than that of E2, a high output signal is detected, and on the other hand, E1 is normal. In the case of the signal transmission system with the amplitude B, a low output signal is detected because the potential difference is smaller than that of E2.

This detection signal is arranged in the next stage, and a certain reference voltage set value is input to the comparison circuit 14 which determines the output depending on whether the input signal is within a predetermined range or not, and the reference voltage set value is set. On the other hand, by detecting a signal component that is less than or equal to or less than that, it can be determined that the value is less than or equal to the set value and that the value is greater than or equal to the set value. By displaying the detection result on a display element (such as a light emitting diode), disconnection or cracks, pinholes,
A defect such as a short circuit can be detected, and by using the conductive rubber 8, it is possible to suppress the occurrence of scratches, stains and the like on the surface of the electrode 2 and improve the reliability.

Further, as shown in FIG. 3, the input circuit of the selection circuit 12 is switched by the counter circuit 17 synchronized with the clock signal of the reference clock generation circuit 16 in the case of a 4-digit drive. Have T / 4 to each other
Four types of digit pulses are generated, each of which is out of phase with each other. T1 of this digit pulse corresponds to the digit of 1 of the counter and is 1 in order.
The digit of 0 is T2, the digit of 100 is T3, the digit of 1000 is T4
Correspond to. Since the counter circuit 17 has a built-in BCD code for notifying the result of each counted number,
By inputting the BCD code output to the selector circuit 12, input switching of the selector circuit 12 is digitally controlled, and a plurality of electrodes can be automatically selected.
The inspection work efficiency can be improved.

Further, as shown in FIG. 4, a driver is provided in which a BCD circuit 18 having another signal system is provided in the subsequent stage of the selection circuit 12 for selecting an input signal, and the data output from the BCD circuit 18 is configured in the next stage. By inputting to a driver / decoder circuit 19 having a built-in circuit and a decoder circuit and supplying the output data thereof to a display element 20 (7-segment LED), it becomes possible to detect the input setting state of the selection circuit 12, resulting in a defect. The point can be measured.

Further, the pseudo signal 10 connected to the electrode 3
It is possible to prevent the surface of the electrode 3 from being damaged by using either Au or Pd as the material of the prober 11 for taking out.

Further, as shown in FIG. 5, the conductive rubber 8 having the common electrode 7 is placed on the flexible printed circuit board 21 having both surfaces patterned at the same pitch as the electrode 3, and the flexible printed circuit board 21 is placed. By configuring the selection circuit 12 on the end face side of the, the pseudo signal 10 is supplied to the selection circuit 12 and the same inspection as described above can be performed.

[0025]

As described above, according to the present invention, it is possible to detect defects such as disconnection, cracks, shorts, etc., which have occurred in the back electrode pattern, and since the conductive rubber is used, the electrode surface is not scratched or damaged. Generation of dirt and the like can be suppressed and reliability can be improved.

Further, when switching the input of the selection circuit, it is possible to automatically select a plurality of electrodes by forming a counter circuit synchronized with the reference clock signal and performing digital control, thereby improving inspection work efficiency. You can

Further, it becomes possible to detect the input setting state of the selector circuit and measure the defective portion.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a method for inspecting a back electrode for a display device of the present invention.

FIG. 2 is an explanatory diagram of a circuit used in the embodiment.

FIG. 3 is a waveform diagram of each part for explaining the operation of the counter circuit used in the embodiment.

FIG. 4 is a circuit configuration diagram of input setting position detection in the embodiment.

FIG. 5 is a sectional view of electrode connection in the same embodiment.

FIG. 6 is an explanatory view of a conventional method for inspecting a back electrode for a display device.

[Explanation of symbols]

 1 Back Electrode Substrate 2 Electrode 3 Electrode 4 Back Electrode Pattern 7 Common Electrode 8 Conductive Rubber 9 Holding Plate 10 Pseudo Signal 11 Prober 12 Selection Circuit 13 Differential Amp 14 Comparison Circuit 15 Display Element 16 Reference Clock Generation Circuit 17 Counter Circuit 18 BCD Circuit 19 Driver / Decoder Circuit 20 Display Element 21 Flexible Printed Circuit Board

Claims (6)

[Claims] 1. A method of inspecting a back electrode for a display device, wherein a pattern having left and right symmetrical electrodes on a back electrode substrate is arranged and formed in a multi pattern, which is common to one of the patterns arranged in the multi pattern. After placing a conductive rubber having an electrode and connecting the pattern and the conductive rubber, a pseudo signal having a square wave or a sine wave is input to the common electrode portion of the conductive rubber, and the pseudo input signal Is provided in the vicinity of a stylus (hereinafter referred to as a prober) configured on the other side electrode, and is supplied to an input signal detecting means. 2. An input signal detection means, an input signal selection circuit, a counter circuit for controlling the selection circuit, a differential Amp for detecting an input signal potential difference and a reference input signal, and the differential Am.
The method for inspecting a back electrode for a display device according to claim 1, wherein the input signal detection circuit comprises a comparison circuit for comparing p output signals and a display element for displaying an output signal of the comparison circuit. 3. A binary coded decimal circuit (hereinafter referred to as BCD) having another signal system at a stage subsequent to the input signal selection circuit, a driver / decoder circuit, and the driver / decoder circuit.
The method for inspecting a back electrode for a display device according to claim 2, wherein a display element for displaying output data of the decoder circuit is configured. 4. The material of the conductive rubber having a common electrode is A
2. The method for inspecting a back electrode for a display device according to claim 1, wherein the back electrode is u, Ag or carbon. 5. The material of the prober formed in the pattern on the other side is either Au or Pd.
A method for inspecting a back electrode for a display device as described above. 6. The method for inspecting a back electrode for a display device according to claim 1, wherein the connecting means for the pattern on the other side is composed of a conductive rubber and a flexible printed board.