JPS63261414A - Self-diagnosis circuit for conductive pattern - Google Patents

Abstract

PURPOSE:To execute a disconnection defect test or a test for fatigue, deterioration or the like by diagnosing a conductive pattern based on decision results outputted from plural comparing means. CONSTITUTION:An electric signal outputted from a conductive pattern to which a prescribed voltage is impressed by an impressing means M1 is compared with respectively different prescribed reference values by plural comparing means M2. A diagnosis means 3 diagnosis the conductive pattern based on the decision results outputted from the means M2. When the prescribed reference values of the means M2 are set up as a reference value for detecting the disconnection of the conductive pattern and a reference value for detecting the degree of fatigue, the disconnection and fatigue of the conductive pattern can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] Object of the Invention The present invention relates to a conductive pattern self-diagnosis circuit that performs self-diagnosis of a conductive pattern.

[Prior Art] Conventionally, in a touch switch having a conductive pattern, for example, a plurality of drive lines and sense lines arranged in an X-Y matrix, it has been difficult to determine whether there is a part that is always on when the power is turned on. (self-diagnosis). Thereby, it is possible to detect an abnormal state in which the drive line or sense line serving as the surface electrode becomes slack due to temperature change or strong pressing force and is constantly in contact with the sense line or drive line serving as the lower layer electrode.

[Problems to be Solved by the Invention] However, abnormal states of touch switches and the like as conductive patterns are not limited to the above-mentioned short circuit phenomenon, but also phenomena such as disconnection of the drive line or sense line, fatigue and fatigue due to changes over time, etc. A phenomenon of deterioration may also be considered. However, in conventional touch switches, etc., it is only possible to perform a test to determine a short circuit phenomenon as a self-diagnosis, which may cause the following problems.

In other words, if the drive line or sense line is disconnected, it may not be possible to detect input such as a pressed touch position, and if the drive line or sense line has deteriorated due to fatigue, the input detection sensitivity may be affected. There are problems such as a decrease in

The conductive pattern self-diagnosis circuit of the present invention was created with the aim of solving the above problem, and is configured as follows.

Structure of the Invention [Means for Solving Problems] The conductive pattern self-diagnosis circuit of the present invention is a circuit for self-diagnosing a conductive pattern, as shown in FIG. Application means (Ml) for applying a predetermined voltage to one end of the
), and a plurality of comparing means (M2
), and diagnostic means (M3) for diagnosing the conductive pattern based on the determination results output from the plurality of comparison means (M2).

[Function] The conductive pattern self-diagnosis circuit of the present invention having the above configuration functions as follows.

The conductive pattern self-diagnosis circuit of the present invention has an application means (Ml
), the electrical signal output from the conductive pattern to which a predetermined voltage has been applied is compared with predetermined reference values in various fields by a plurality of comparison means (M2), and based on the judgment results output from the plurality of comparison means (M2). The diagnostic means (M3) then moves to diagnose the conductive pattern. As a result, if the predetermined reference values of the plurality of comparison means (M2) are set as the reference value for detecting disconnection of the conductive pattern and the reference value for detecting the degree of fatigue, it will work to detect the disconnection and degree of fatigue of the conductive pattern. .

[Embodiment] Next, in order to further clarify the structure of the conductive pattern self-diagnosis circuit of the present invention, a preferred embodiment will be described with reference to the drawings. The conductive pattern self-diagnosis circuit of this embodiment shown in FIG. 2 employs the conductive pattern self-diagnosis circuit of the present invention in a touch switch input detection device that is arranged in an X-Y matrix and detects a pressed touch position. It is.

As shown in FIG. 2, the conductive pattern self-diagnosis circuit of this embodiment has a plurality of sense lines χ1 to χ5 as conductive patterns formed by depositing indium oxide (so-called ITO) on a substrate such as a polyester film. and drive line y
1 to y5 arranged in an X-Y matrix, selection switching circuits 3a to 3d for selecting arbitrary sense lines and/or drive lines of the touch switch 1, and so-called CPU 5a, ROM 5b, and RAM 5.
C, etc., and an analog/digital converter (hereinafter referred to as an A/D converter) 56 and an external input/output circuit 5.
e and an electronic control device 5 as a logic operation circuit, which are interconnected by a bus 5f. Note that the electronic control device 5 may be configured integrally with the electronic control device that detects the input of the touch switch 1, or may be configured separately.

The input side of the selection switching circuit 3a is connected to a power supply of a predetermined voltage E (V) via a signal line 10, and the plurality of output sides thereof are connected to a sense line χ.
Similarly, one end of each of 1 to χ5 and the selection switching circuit 3
The input side of b is connected to a power source of a predetermined voltage E (V) via a signal line 11, and the plurality of output sides thereof are connected to one end of each of drive lines y1 to y5. On the other hand, the plurality of input sides of the selection switching circuit 3C are connected to the other ends of each of the sense lines χ1 to χ5, and the output side thereof is connected to the A/D converter 5d of the electronic control unit 5 via the signal line 12, and similarly, The plurality of input sides of the selection switching circuit 3d are connected to the other ends of each of the drive lines y1 to y5,
The output side is connected to the A/D converter 5d via the signal line 13,
Each is connected. Furthermore, the output sides of the selection switching circuits 3C and 3d are both grounded via a resistor R1. Further, each of the selection switching circuits 3a to 3d is
It is connected to an external input/output circuit 5e of the electronic control device 5 via signal lines 14 to 17.

FIG. 3 shows the operation of this embodiment having the above configuration.

This will be explained with reference to the flowcharts shown in FIGS. 4 and 6. ``Disconnection failure test routine'' shown in Figure 3, ``Fatigue level test routine'' shown in Figure 4, and ``Fatigue level test routine'' shown in Figure 6.
Each of the "Short Circuit Failure Test Routines" is executed only once at power-on. First, the processing of the "disconnection defect test routine" will be explained.

First, the CPU 5a of the electronic control unit 5 sets the value of the variable i to 1.
Step 5100), after which the selection switching circuit 3a is switched via the external input/output circuit 5e and the signal line 14, and similarly the selection switching circuit 3C is switched via the signal line 12, and one end of the sense line χi is switched. A predetermined voltage E is applied to the sense line χi, and the voltage value VIN at the other end of the sense line χi is inputted via the signal line 12 and the A/D converter 5d (step 5105).

In the following step 5110, the voltage value V as an input signal is
It is determined whether IN is greater than or equal to a reference value VL (described in detail in 41). Here, if the judgment is affirmative, then the value of the variable i is incremented (step S
115), it is determined whether the value of this variable i is 6 or more (step 5120).

If a negative determination is made in step 3120, the process returns to step 5105 and repeats the above-described process (steps 3105 to 8115). That is, the CPU
5a switches the selection switching circuits 3a and 3C, respectively;
A process is performed in which the voltage value VIN on the ground side inputted for all of the sense lines χ1 to χ5 is compared with the reference value ■[.

On the other hand, if the determination in step 5120 is affirmative, the value of variable j is set to 1 (step 3125
), the selection switching circuits 3b and 3d are respectively switched to perform the same processing as the above-mentioned processing (steps 8105 to 3120) on the drive line yj (step 513).
0 to 8145).

Here, step 3110 or step 5135
If a negative determination is made in step S, it is determined that any of the tested sense lines χ1 to χ5 or drive lines y1 to y5 is disconnected, and the process proceeds to step S.
Proceeding to step 50 and subsequent steps, a report of the disconnection defect is created (step 5150), and a process is performed to output an alarm signal via the external input/output circuit 5e (step 51).
55). This will be explained in detail.

The input signal VIN to be compared with the reference voltage VL is expressed as follows: If the resistance values of the sense lines χ1 to χ5 and the drive lines y1 to y5 are R[Ω, then in a normal conduction state, VIN=R1XE/( R+R1). Therefore, in this embodiment, the reference value VL
R1XE/(2R+R1)(7) is set to a predetermined small value, and when the detected input signal VIN is less than the reference value VL, it is determined that the wire is disconnected.

Next, the "fatigue level test routine" shown in FIG. 4 will be explained.

Step 5 of the “Dotted Line Failure Test Routine” shown in Figure 3
100 and 8105, the CPU 5a sets the value of the variable i to 1 (step 3200), and then switches the selection switching circuits 3a and 3C to select the ground side voltage value of the sense line χi as the input signal χi. Step 5205> performs detection processing. After this, the detected input signal ■i is stored in the RAM 5G, step 5210>,
The above steps 5205 to 210 are executed for all sense lines (steps 5205 to 522
0).

When the input signals Vi of all the sense lines χ1 to χ5 are detected, the minimum value min V of the detected input signals vi becomes the reference value VH (described in detail later).
It is determined whether or not the above is true (step 5225>
. Here, if an affirmative determination is made, the above processing (steps 5200 to 5200) is also performed for the drive lines y1 to y5.
225) is executed (step 5230).
to 8255>.

On the other hand, if a negative determination is made in step 5225 or 5255, the tested sense lines χ1 to χ5
Alternatively, it is determined that one of the drive lines y1 to y5 is fatigued or deteriorated, and the process proceeds to step 5260 and thereafter, where a report of fatigue deterioration is created (step 5260>) and a process of outputting an alarm signal is performed ( Step 3265>. This will be explained in detail together with the reference value VH.

As shown in the graph of FIG. 5, the reference value VH is the input signal V=R1xE/(R+R1) detected when the sense lines χ1 to χ5 and the drive lines y1 to y5 are normal.
It is set to a slightly smaller value.

Generally, as fatigue and deterioration of a conductive pattern progresses, its conductivity decreases and its resistance value increases. Therefore, the voltage drop across the conductive pattern also increases.

As a result, in this embodiment, the sense lines χ1 to χ
5 and any one of the drive lines y1 to y5 becomes fatigued or deteriorated, the minimum value m1nV of the input signal will fall below the reference value VH. Moreover, when the input signal minimum value min v is less than the reference value VL, it is the case of the above-mentioned disconnection state.

In addition, in the defect report creation process of step 5260, the number of the sense line or drive line corresponding to the minimum input signal value m1nV less than the reference value VH may be simply stored; It may be configured such that the level of fatigue level is stored and a history of the level of fatigue is created together with the previous test results and the like.

The "short-circuit failure test routine" shown in FIG. 6 is executed according to the same process as the well-known digital scan for detecting the pressed position of a touch switch.

That is, one end of any sense line χi is connected to the power supply side (steps 5300 and 3305), and the input signal V
I! 74G: Comparison with the reference value VL (steps 5310 to 5325) is performed for all sense lines (steps 5310 to 5335). At this time,
If a negative determination is made in step 5315, it is determined that there is a short circuit failure, and the process proceeds to steps 5340 and 5345. In other words, when the power is turned on, there is no pressed and touched location, so the detected touch position is short-circuited between one of the sense lines χ1 to χ5 and one of the drive lines y1 to y5. Furthermore, step 53
The reference value V[, which is compared with the input signal VIN in step 15, is based on the above-mentioned "open circuit failure test" based on the maximum series resistance value (approximately 2R) between the sense line χ5 and the drive line y1 when the point P1 is touched. This is the same reference value as V[ used.

According to the conductive pattern self-diagnosis circuit of the present embodiment described in detail above, the short-circuit failure test of the sense lines χ1 to χ5 and the drive lines y1 to y5, which are the conductive patterns forming the touch switch 1, can be performed in a conventional manner. It has the excellent effect of being able to perform disconnection failure tests and fatigue tests that were previously impossible. As a result, it is possible to promptly replace the touch switch 1 determined to be defective, and to provide a touch switch input detection device that is free from erroneous detection. In addition, in the “fatigue test routine” of this example,
Another advantage is that the sense line or drive line that is most fatigued or degraded can be detected quickly. Furthermore,
When the conductive pattern self-diagnosis circuit of this embodiment is used with a CRT display device or the like, the program must be programmed in advance to avoid using the portion of the screen on the touch panel 1 that corresponds to a sense line or drive line that has been determined to be defective. If it is created, there is no need to immediately replace the touch panel 1 that is determined to be defective.

The conductive pattern self-diagnosis circuit of the present invention is not limited to the above-mentioned embodiments, and can be implemented in various forms without departing from the gist of the present invention. For example, although this embodiment has been configured as a logic operation circuit using a microconverter or the like, it may also be configured as a discrete circuit using a so-called comparator or the like.

Effects of the Invention According to the conductive pattern self-diagnosis circuit of the present invention, the conductive pattern can be diagnosed by comparing it with a predetermined reference value using the comparing means. As a result, if the conductive pattern self-diagnosis circuit of the present invention is adopted in a touch switch input detection device that detects a pressed touch position, a matrix switch used in a so-called keyboard, etc.,
Tests for disconnection and fatigue, which were previously impossible to perform,
It has an excellent effect of being able to perform tests for deterioration, etc.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the basic configuration of a conductive pattern self-diagnosis circuit according to the present invention, FIG. 2 is a schematic configuration diagram showing a conductive pattern self-diagnosis circuit according to an embodiment of the present invention, and FIG. A flowchart showing the processing of routine J,
Fig. 4 is a flowchart showing the processing of the "fatigue level test routine", Fig. 5 is an explanatory diagram illustrating the set voltage values of the reference values VH and V[, and Fig. 6 shows the processing of the "short circuit failure test routine". It is a flowchart. 1... Touch switch 5... Electronic control device R1.
··Resistor

Claims (2)

[Claims] (1) A circuit that performs self-diagnosis of a conductive pattern, comprising an application means for applying a predetermined voltage to one end of the conductive pattern, and comparing an electrical signal output from the other end of the conductive pattern with different predetermined reference values. A conductive pattern self-diagnosis circuit comprising: a plurality of comparison means for diagnosing the conductive pattern based on determination results output from the plurality of comparison means; (2) At least one of the plurality of comparison means sets a predetermined reference value for detecting disconnection of the conductive pattern, and at least two of the plurality of comparison means determines the degree of fatigue of the conductive pattern. 2. The conductive pattern self-diagnosis circuit according to claim 1, wherein the conductive pattern self-diagnosis circuit is configured by setting a predetermined reference value for detecting the conductive pattern.