Detection circuit for touch screen

Abstract

The utility model relates to a detection circuit for a touch screen. A port of the touch screen is sequentially connected with a voltage dividing module, a detection module and an output module. The voltage dividing module is used for simulating voltage when the touch screen is pressed and inputting the voltage to the detection module, the detection module is used for detecting the voltage, and when the voltage is within a set voltage range, the output module displays the voltage. The voltage division module of the detection circuit can simulate voltage division when the touch screen is pressed, so that resistance detection can be performed on a plurality of ports of the touch screen at the same time by pressing the touch screen once during detection, and rapidness and convenience are achieved; the detection module is used for limiting the standard voltage range of the touch screen and comparing the partial voltage generated by the voltage dividing module, if the partial voltage is within the standard voltage range, the detection result is displayed on the output module, automatic detection can be achieved, manual operation is not needed, time and labor are saved, and the detection result is accurate.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of industrial tablet computer, and relates to the touch screen of tablet computer, especially a detection circuit for touch screen. BACKGROUND

[0002] The touch screen of industrial tablet computer needs to be detected after production, and the manufacturer usually uses single-chip microcomputer or PLC chip to detect, connects five ports of the touch screen and applies voltage, detects current through the single-chip microcomputer or PLC chip, and then calculates resistance value through voltage and current to ensure that the quality of the touch screen is qualified.

[0003] However, the purchaser of the touch screen usually does not have the above professional equipment, and the cost is high if the equipment is purchased, so the purchaser can only use the resistance position of the multimeter to detect the five ports of the touch screen in turn, and then presses the touch screen to detect, which is complicated, time-consuming, low in efficiency, and large in human error.

[0004] Therefore, the utility model provides a detection circuit for touch screen to solve the above problems. UTILITY MODEL CONTENTS

[0005] The utility model aims at overcoming the defects of the prior art, and provides a detection circuit for touch screen, which is simple in structure and rapid in detection.

[0006] To solve the above problems, the technical scheme of the utility model is as follows:

[0007] A detection circuit for touch screen, the ports of the touch screen are connected with a voltage division module, a detection module and an output module in turn;

[0008] The voltage division module is used for simulating voltage when the touch screen is pressed, and the voltage is input to the detection module; the detection module is used for detecting the voltage, and the output module displays when the voltage is within the set voltage range.

[0009] In a further embodiment, the detection module comprises an upper limit detection unit and a lower limit detection unit, one end of the upper limit detection unit and the lower limit detection unit is connected with the voltage division module, and the other end of the upper limit detection unit and the lower limit detection unit is connected with the output module;

[0010] The upper limit detection unit is used for detecting the maximum voltage of the voltage division module, and the lower limit detection unit is used for detecting the minimum voltage of the voltage division module.

[0011] In a further embodiment, the voltage division module comprises a third resistor and a fourth resistor, one end of the touch screen is grounded, and the other end of the touch screen is connected with the fourth resistor, the third resistor and an external voltage in turn.

[0012] In a further embodiment, the upper limit detection unit comprises a first operational amplifier, a first resistor and a second resistor, the 2 pin of the first operational amplifier is connected to the third resistor and the fourth resistor respectively, the 3 pin of the first operational amplifier is connected to the external voltage through the first resistor, and the 3 pin is also connected to the ground through the second resistor.

[0013] In a further embodiment, the 1 pin of the first operational amplifier is connected to the output module, the 4 pin of the first operational amplifier is grounded, and the 8 pin of the first operational amplifier is connected to the external voltage.

[0014] In a further embodiment, the lower limit detection unit comprises a second operational amplifier, a fifth resistor and a sixth resistor, the 6 pin of the second operational amplifier is connected to the third resistor and the fourth resistor respectively, the 5 pin of the second operational amplifier is connected to the external voltage through the fifth resistor, and the 5 pin is also connected to the ground through the sixth resistor.

[0015] In a further embodiment, the 7 pin of the second operational amplifier is connected to the output module, the 4 pin of the second operational amplifier is grounded, and the 8 pin of the second operational amplifier is connected to the external voltage.

[0016] In a further embodiment, the output module comprises a seventh resistor and an LED lamp, one end of the seventh resistor is connected to the 1 pin of the first operational amplifier, the other end of the first resistor is connected to the positive electrode of the LED lamp, and the negative electrode of the LED lamp is connected to the 7 pin of the second operational amplifier.

[0017] In a further embodiment, when the output voltage value of the voltage division module is lower than the predetermined voltage value of the upper limit detection unit, the first operational amplifier outputs a high level, otherwise it outputs a low level;

[0018] When the output voltage value of the voltage division module is higher than the predetermined voltage value of the lower limit detection unit, the second operational amplifier outputs a low level, otherwise it outputs a high level.

[0019] In a further embodiment, when the first operational amplifier outputs a high level and the second operational amplifier outputs a low level, the LED lamp is turned on to emit light.

[0020] Compared with the prior art, the beneficial effects of the utility model are:

[0021] 1、The detection circuit is sequentially connected with the voltage division module, the detection module and the output module on a plurality of ports of the touch screen, the voltage division module can simulate the voltage division when pressing the touch screen, so that the resistance of the plurality of ports of the touch screen can be detected at one time when pressing the touch screen, which is fast and convenient; the detection module is used for limiting the standard voltage range of the touch screen, and is used for comparing the voltage division generated by the voltage division module, if the voltage division is within the standard voltage range, the detection result is displayed on the output module, automatic detection can be realized, manual operation is not needed, time and labor are saved, and the detection result is accurate.

[0022] 2、The detection module of the detection circuit comprises an upper limit detection unit and a lower limit detection unit, the upper limit detection unit comprises a first operational amplifier, one pin of the first operational amplifier inputs a maximum voltage value, another pin of the first operational amplifier inputs a voltage division value of the voltage division module, if the voltage division value is lower than the maximum voltage value, the first operational amplifier outputs a high level; similarly, if the voltage division value input by the second operational amplifier of the lower limit detection unit is higher than a minimum voltage value, the second operational amplifier outputs a low level, and the LED lamp of the output module is turned on to emit light, indicating that the detection is qualified.

[0023] 3、The detection circuit has simple structure, can select resistors with corresponding resistance values according to the model of the touch screen, has strong applicability, wide measurement range, and can be used for touch screens of various specifications; measurement is convenient and fast, and only needs to connect the detection circuit to each port of the touch screen, and the light emitting condition of the LED lamp can be observed to obtain the detection result. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a module connection schematic diagram of a detection circuit for a touch screen;

[0025] Figure 2 It is a circuit diagram of a detection circuit for a touch screen.

[0026] In the figure: 1, touch screen port; 2, voltage division module; 3, detection module; 31, upper limit detection unit; 32, lower limit detection unit; 4, output module. DETAILED DESCRIPTION

[0027] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only for description purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first", "second" and the like can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0028] Example 1:

[0029] A detection circuit for a touch screen, as Figure 1 ,Figure 2 As shown, the touch screen detection device comprises a touch screen port 1, a voltage division module 2, a detection module 3 and an output module 4, the touch screen port 1 is connected to the voltage division module 2, the detection module 3 and the output module 4 in sequence, the voltage division module 2 outputs the resistance value after voltage division to the detection module 3 by simulating the resistance and voltage division when pressing the touch screen, if the voltage division is within the predetermined voltage range of the detection module 3, the output module 4 displays, that is, the touch screen detection is qualified.

[0030] The touch screen has five touch screen ports 1, and one of the ports UR is taken as an example in the embodiment; the voltage division module 2 comprises a third resistor R3 and a fourth resistor R4, one end of the port UR is grounded, the other end of the port UR is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to an external voltage VCC, and the third resistor R3 and the fourth resistor R4 are selected according to the use requirement to simulate the resistance and voltage division generated when pressing the touch screen.

[0031] The detection module 3 comprises an upper limit detection unit 31, the upper limit detection unit 31 comprises a first operational amplifier U1A, a first resistor R1 and a second resistor R2, the 1 pin of the first operational amplifier U1A is connected to the output module 4 for outputting the comparison result; the 4 pin of the first operational amplifier U1A is grounded, the 8 pin of the first operational amplifier U1A is connected to the external voltage VCC, the 2 pin of the first operational amplifier U1A is connected to the third resistor R3 and the fourth resistor R4 respectively, the 3 pin of the first operational amplifier U1A is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the external voltage VCC, the 3 pin of the first operational amplifier U1A is also connected to one end of the second resistor R2, and the other end of the second resistor R2 is grounded; when the voltage value output by the voltage division module 2 is higher than the predetermined voltage value of the upper limit detection unit 31, that is, the voltage value of the 2 pin of the first operational amplifier U1A is higher than the voltage value of the 3 pin, the resistance of the touch screen is abnormally higher than the standard, the 1 pin of the first operational amplifier U1A outputs a low level, otherwise, the voltage value of the 2 pin of the first operational amplifier U1A is lower than the voltage value of the 3 pin, and the 1 pin of the first operational amplifier U1A outputs a high level. Preferably, the model of the first operational amplifier U1A is LM392.

[0032] The detection module 3 further comprises a lower limit detection unit 32, which comprises a second operational amplifier U1B, a fifth resistor R5 and a sixth resistor R6. The 7th pin of the second operational amplifier U1B is connected to the output module 4 for outputting a comparison result; the 4th pin of the second operational amplifier U1B is grounded; the 8th pin of the second operational amplifier U1B is connected to an external voltage VCC; the 6th pin of the second operational amplifier U1B is connected to the third resistor R3 and the fourth resistor R4 respectively; the 5th pin of the second operational amplifier U1B is connected to one end of the fifth resistor R5, and the other end of the fifth resistor R5 is connected to the external voltage VCC; the 5th pin of the second operational amplifier U1B is also connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is grounded; when the voltage value output by the voltage dividing module 2 is lower than the predetermined voltage value of the lower limit detection unit 32, i.e. the voltage value of the 6th pin of the second operational amplifier U1B is lower than the voltage value of the 5th pin, the resistance of the touch screen is abnormally lower than the standard, the 1st pin of the second operational amplifier U1B outputs a high level, otherwise, the voltage value of the 6th pin of the second operational amplifier U1B is higher than the voltage value of the 5th pin, and the 7th pin of the second operational amplifier U1B outputs a low level. Preferably, the model of the second operational amplifier U1B is LM392.

[0033] The output module 4 comprises a seventh resistor R7 and an LED lamp D1. One end of the seventh resistor R7 is connected to the 1st pin of the first operational amplifier U1A, the other end of the first resistor R7 is connected to the positive electrode of the LED lamp D1, and the negative electrode of the LED lamp D1 is connected to the 7th pin of the second operational amplifier U1B. When the 1st pin of the first operational amplifier U1A outputs a high level and the 7th pin of the second operational amplifier U1B outputs a low level, the LED lamp D1 is turned on and emits light, indicating that the resistance of the touch screen is within the standard range and the detection is qualified. In addition, when the 1st pin of the first operational amplifier U1A outputs a low level, the LED lamp D1 has no driving power, and when the 7th pin of the second operational amplifier U1B outputs a high level, the LED lamp D1 is reverse biased, and the LED lamp D1 does not emit light, indicating that the resistance of the touch screen is abnormal and the detection fails.

[0034] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A detection circuit for a touchscreen, characterized in that, The ports of the touch screen are connected in sequence to the voltage divider module, the detection module, and the output module; The voltage divider module is used to simulate the voltage when the touch screen is pressed, and inputs the voltage to the detection module. The detection module is used to detect the voltage, and when the voltage is within a set voltage range, the output module displays it. The detection module includes an upper limit detection unit and a lower limit detection unit. One end of the upper limit detection unit and the lower limit detection unit are respectively connected to the voltage divider module, and the other end of the upper limit detection unit and the lower limit detection unit are respectively connected to the output module. The upper limit detection unit is used to detect the maximum voltage of the voltage divider module, and the lower limit detection unit is used to detect the minimum voltage of the voltage divider module.

2. The detection circuit for a touchscreen according to claim 1, characterized in that, The voltage divider module includes a third resistor and a fourth resistor. One end of the touch screen is grounded, and the other end of the touch screen is connected in sequence to the fourth resistor, the third resistor, and an external voltage.

3. The detection circuit for a touchscreen according to claim 2, characterized in that, The upper limit detection unit includes a first operational amplifier, a first resistor, and a second resistor. Pin 2 of the first operational amplifier is connected to the third resistor and the fourth resistor, respectively. Pin 3 of the first operational amplifier is connected to an external voltage through the first resistor, and pin 3 is also grounded through the second resistor.

4. The detection circuit for a touchscreen according to claim 3, characterized in that, Pin 1 of the first operational amplifier is connected to the output module, pin 4 of the first operational amplifier is grounded, and pin 8 of the first operational amplifier is connected to an external voltage.

5. The detection circuit for a touchscreen according to claim 4, characterized in that, The lower limit detection unit includes a second operational amplifier, a fifth resistor, and a sixth resistor. The 6th pin of the second operational amplifier is connected to the third resistor and the fourth resistor, respectively. The 5th pin of the second operational amplifier is connected to an external voltage through the fifth resistor, and the 5th pin is also grounded through the sixth resistor.

6. The detection circuit for a touchscreen according to claim 5, characterized in that, Pin 7 of the second operational amplifier is connected to the output module, pin 4 of the second operational amplifier is grounded, and pin 8 of the second operational amplifier is connected to an external voltage.

7. The detection circuit for a touchscreen according to claim 6, characterized in that, The output module includes a seventh resistor and an LED. One end of the seventh resistor is connected to pin 1 of the first operational amplifier, the other end of the first resistor is connected to the positive terminal of the LED, and the negative terminal of the LED is connected to pin 7 of the second operational amplifier.

8. The detection circuit for a touchscreen according to claim 7, characterized in that, When the output voltage of the voltage divider module is lower than the predetermined voltage of the upper limit detection unit, the first operational amplifier outputs a high level; otherwise, it outputs a low level. When the output voltage of the voltage divider module is higher than the predetermined voltage of the lower limit detection unit, the second operational amplifier outputs a low level; otherwise, it outputs a high level.

9. The detection circuit for a touchscreen according to claim 8, characterized in that, When the first operational amplifier outputs a high level and the second operational amplifier outputs a low level, the LED light is turned on and illuminates.

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