Dimming circuit for infrared touch screen and control method thereof

Abstract

The application discloses a dimming circuit for an infrared touch screen and a control method thereof, comprising a controller, a transmitting component, a receiving component, a transmitting adjustment signal circuit, a receiving operational amplifier adjustment circuit, an operational amplifier adjustment amplification circuit and a signal acquisition circuit, and the signal amplitude is controlled within ±5% by adopting a combination mode of transmitting adjustment and receiving adjustment, so that the infrared touch screen signal consistency is realized; the transmitting adjustment signal circuit and the operational amplifier adjustment amplification circuit are combined to control the adjustment mode, the adjustment gear is more, the adjustment signal range is large, the same circuit parameter can be used to realize the consistency of the overall signal of infrared touch screens with different sizes, the production and research and development efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of control circuit technology, and in particular to a dimming circuit and control method for an infrared touch screen. Background Technology

[0002] Infrared touchscreens are a type of touchscreen that enables touch functionality. Currently, infrared touchscreens consist of a controller, a transmitting control circuit, transmitting diodes, a receiving control circuit, receiving diodes, a receiving operational amplifier adjustment circuit, and a signal acquisition circuit. The transmitting diode array and the receiving diode array are distributed around the display screen, using a fan-shaped scanning method. They require highly consistent AD signals to satisfy the controller's analysis and enable more functional requirements of the infrared touchscreen.

[0003] Because infrared touchscreens use a multiple-transmit, multiple-receive scanning method, a single transmitting diode will correspond to multiple receiving diodes, and a single receiving diode will also receive signals from multiple transmitting diodes, such as... Figure 4 As shown, the infrared lamps of an infrared touchscreen have varying energy levels at different angles along the X-axis. When a single lamp is working, there will be a phenomenon where the signal is strong at the center of the lamp and gradually weakens at the sides. Figure 4 As shown, the signal at the center angle of the lamp's X-axis is much stronger than the signals at the two sides of the lamp's X-axis; the overall signal of the infrared touchscreen will vary due to differences in the performance parameters of the infrared tubes themselves, and the parameters of the infrared tube driver components during mass production, such as the difference in the transistor amplification factor from 100 to 300, resulting in... Figure 6 The infrared touchscreens shown exhibit inconsistent photoelectric signal strength. To ensure signal quality for touchscreens of different sizes, smaller sizes require smaller circuit parameters, and larger sizes require larger circuit parameters, making it impossible to maintain consistent circuit parameters. High consistency in the performance parameters of infrared diodes and driving components further complicates the mass production of touchscreens of varying sizes. This also increases the difficulty of implementing more functions on the infrared touchscreens, such as multi-touch fine and thick pen recognition. Summary of the Invention

[0004] The purpose of this invention is to provide a dimming circuit and its control method for an infrared touchscreen in order to solve the above-mentioned problems.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] A dimming circuit for an infrared touchscreen includes a controller, a transmitting component, a receiving component, a transmitting modulation signal circuit, a receiving operational amplifier modulation circuit, an operational amplifier modulation and amplification circuit, and a signal acquisition circuit. The signal output terminal of the controller is connected to the signal input terminals of the transmitting component, the receiving component, the transmitting modulation signal circuit, and the operational amplifier modulation and amplification circuit, respectively. The light emitted by the transmitting component is received by the receiving component. The input terminal of the receiving operational amplifier modulation circuit is connected to the signal output terminal of the receiving component and the signal output terminal of the operational amplifier modulation and amplification circuit, respectively. The signal acquisition circuit is used to acquire the signal from the receiving operational amplifier modulation circuit.

[0007] Preferably, the transmitting component includes a transmitting control circuit and a transmitting diode, the signal output terminal of the controller is connected in series with the transmitting control circuit and the transmitting diode, and the signal output terminal of the transmitting adjustment signal circuit is connected to the signal input terminal of the transmitting diode.

[0008] Preferably, the receiving component of the present invention includes a receiving control circuit and a receiving diode. The signal output terminal of the controller is connected in series with the receiving control circuit and the receiving diode. The light emitted by the emitting diode is received by the receiving diode. The signal output terminal of the receiving diode is connected to the signal input terminal of the receiving operational amplifier adjustment circuit.

[0009] Preferably, the emission adjustment signal circuit of the present invention includes a third transistor connected in series with the positive terminal of the emission diode, which is used by the DA terminal of the controller to control the base voltage and current of the third transistor to adjust the power of the emission diode.

[0010] Preferably, the emission adjustment signal circuit of the present invention includes a third transistor connected in series with the negative terminal of the emission diode, which is used by the DA terminal of the controller to control the base voltage and current of the third transistor to adjust the power of the emission diode.

[0011] Preferably, the operational amplifier adjustment and amplification circuit of the present invention includes a multi-select switch and multiple resistors connected in series on different channels of the multi-select switch. The controller controls the multi-select switch to select resistors of different channels to adjust the amplification factor of the operational amplifier in order to adjust the received photoelectric signal.

[0012] Preferably, the resistors connected in series on different channels of the multi-select switch have different resistance values.

[0013] Preferably, the receiving operational amplifier adjustment circuit of the present invention includes a first amplifier and a second amplifier. The signal input terminal of the first amplifier is connected to the signal output terminal of the receiving diode, and the signal output terminal of the first amplifier is connected in series with the second amplifier and then connected to the AD terminal of the controller.

[0014] A control method for a dimming circuit of an infrared touchscreen, comprising the aforementioned dimming circuit, is implemented according to the following steps:

[0015] S1, the controller sets a typical value for AD, and the controller controls the operational amplifier adjustment circuit through the I / O terminal to make the received signal value close to the typical value of AD;

[0016] S2 adjusts the voltage and current of the base of the third transistor through the DA terminal of the controller, and adjusts the current of the emitting diode. The AD value of the controller's AD terminal acquired by the signal acquisition circuit is within ±5% of the typical AD value, that is, the signal value is consistent, so that the touch screen performance is optimal.

[0017] Preferably, according to step S1, the controller controls the multi-select switch in the operational amplifier adjustment circuit to select resistors with different resistance values ​​for range adjustment, so as to adjust the overall received signal value to be close to the typical AD value.

[0018] Preferably, according to step S2, when the signal acquisition circuit detects that the overall signal at the controller's AD terminal does not meet the set AD typical value ±5% requirement, the transmission adjustment signal circuit intervenes for adjustment. The controller compares each signal with the AD typical value. When the signal is stronger than the AD typical value, the controller controls the transmission adjustment signal circuit to reduce the current operating current of the current transmitting diode. When the signal is weaker than the AD typical value, the controller controls the transmission adjustment signal circuit to increase the current operating current of the current transmitting diode. After fine-tuning each signal, the overall infrared touch screen signal is made consistent, and the touch screen performance is optimal.

[0019] The beneficial effects of this invention are as follows:

[0020] Compared with existing technologies, this invention uses a combination of transmit and receive modulation to control the signal amplitude within ±5%, achieving signal consistency for infrared touchscreens. The combination of transmit modulation signal control circuit and operational amplifier modulation circuit provides multiple modulation levels and a wide modulation signal range, enabling infrared touchscreens of different sizes to achieve overall signal consistency using the same circuit parameters. This improves production and R&D efficiency and reduces production costs. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and, together with their descriptions, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0022] Figure 1 This is a circuit block diagram of a dimming circuit for an infrared touchscreen according to the present invention;

[0023] Figure 2This is a schematic diagram of the adjustment circuit combining the emission adjustment signal circuit for controlling the negative terminal of the emission diode and the operational amplifier adjustment and amplification circuit as described in Embodiment 1 of the present invention;

[0024] Figure 3 This is a schematic diagram of the adjustment circuit combining the emission adjustment signal circuit for controlling the positive electrode of the emission diode and the operational amplifier adjustment and amplification circuit as described in Embodiment 2 of the present invention;

[0025] Figure 4 This is the infrared tube angle diagram described in the background art of this invention;

[0026] Figure 5 This is a schematic diagram of a signal without adjustment circuitry as described in the background section of this invention;

[0027] Figure 6 This is a schematic diagram of a signal with single-ended adjustment as described in the background art of this invention;

[0028] Figure 7 This is the infrared tube angle diagram described in the background art of this invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] like Figures 1-3 As shown, a dimming circuit for an infrared touchscreen includes a controller MCU, a transmitting component, a receiving component, a transmitting modulation signal circuit, a receiving operational amplifier modulation circuit, an operational amplifier modulation and amplification circuit, and a signal acquisition circuit. The signal output terminal of the controller MCU is connected to the signal input terminals of the transmitting component, the receiving component, the transmitting modulation signal circuit, and the operational amplifier modulation and amplification circuit, respectively. The light emitted by the transmitting component is received by the receiving component. The input terminal of the receiving operational amplifier modulation circuit is connected to the signal output terminal of the receiving component and the signal output terminal of the operational amplifier modulation and amplification circuit, respectively. The signal acquisition circuit is used to acquire the signal from the receiving operational amplifier modulation circuit.

[0031] like Figure 1 and Figure 2 As shown, the transmitting component includes a transmitting control circuit and a transmitting diode LED1. The signal output terminal of the controller MCU is connected in series with the transmitting control circuit and the transmitting diode LED1. The signal output terminal of the transmitting adjustment signal circuit is connected to the signal input terminal of the transmitting diode LED1.

[0032] like Figure 1 and Figure 3As shown, the receiving component includes a receiving control circuit and a receiving diode LED2. The signal output terminal of the controller is connected in series with the receiving control circuit and the receiving diode LED2. The light emitted by the emitting diode LED1 is received by the receiving diode LED2. The signal output terminal of the receiving diode LED2 is connected to the signal input terminal of the receiving operational amplifier adjustment circuit.

[0033] like Figures 1-3 As shown, the operational amplifier adjustment and amplification circuit includes a multi-select switch S and multiple resistors R1...Rn connected in series on different channels of the multi-select switch S. The controller MCU controls the multi-select switch S to select resistors R1...Rn from different channels to adjust the amplification factor of the operational amplifier in order to adjust the received photoelectric signal. The resistance values ​​of the resistors R1...Rn connected in series on different channels of the multi-select switch S are different.

[0034] like Figures 1-3 As shown, the receiving operational amplifier adjustment circuit includes a first amplifier AP1 and a second amplifier AP2. The signal input terminal of the first amplifier AP1 is connected to the signal output terminal of the receiving diode LED2. The signal output terminal of the first amplifier AP1 is connected in series with the second amplifier AP2 and then connected to the AD terminal of the controller MCU.

[0035] Example 1:

[0036] like Figure 1 and Figure 2 As shown, the emission adjustment signal circuit includes a third transistor Q3, which is connected in series with the positive terminal of the emission diode LED1. The controller MCU controls the base voltage and current of the third transistor Q3 at the DA terminal to adjust the power of the emission diode LED1.

[0037] like Figure 1 and Figure 2 As shown, the transmit control circuit includes a first transistor Q1 and a second transistor Q2. The emitter of the first transistor Q1 is connected to the negative power supply VCC. The base of the first transistor Q1 is connected to the I / O1 terminal of the controller MCU. The collector of the first transistor Q1 is connected in series with the emitter diode LED1 and then connected to the collector of the second transistor Q2. The base of the second transistor Q2 is connected to the I / O2 terminal of the controller MCU. The emitter of the second transistor Q2 is connected to the collector of the third transistor Q3. The base of the third transistor Q3 is connected to the DA terminal of the controller MCU. The emitter of the third transistor Q3 is grounded.

[0038] Example 2:

[0039] like Figure 1 and Figure 3As shown, the emission adjustment signal circuit includes a third transistor Q3, which is connected in series with the negative terminal of the emission diode LED1. The controller MCU controls the base voltage and current of the third transistor Q3 at the DA terminal to adjust the power of the emission diode LED1.

[0040] like Figure 1 and Figure 3 As shown, the transmit control circuit includes a first transistor Q1 and a second transistor Q2. The emitter of the first transistor Q1 is connected to the emitter of the third transistor Q3. The base of the first transistor Q1 is connected to the I / O1 terminal of the controller MCU. The collector of the first transistor Q1 is connected in series with the emitter diode LED1 and then connected to the collector of the second transistor Q2. The base of the second transistor Q2 is connected to the I / O2 terminal of the controller MCU. The emitter of the second transistor Q2 is grounded. The base of the third transistor Q3 is connected to the DA terminal of the controller MCU. The emitter of the third transistor Q3 is connected to the negative power supply VCC.

[0041] like Figures 1-3 As shown, a control method for a dimming circuit of an infrared touchscreen includes the aforementioned dimming circuit, and the method is implemented according to the following steps:

[0042] S1, the controller MCU sets a typical AD value, the controller MCU controls the multi-select switch S in the operational amplifier adjustment circuit through the I / O terminal to select resistors R1...Rn with different resistance values ​​to adjust the range, and adjust the overall received signal value to be close to the typical AD value;

[0043] S2, by adjusting the voltage and current of the base of the third transistor Q3 through the DA terminal of the controller MCU, the current of the emitting diode LED1 is adjusted. The AD value of the controller MCU AD terminal acquired by the signal acquisition circuit is within ±5% of the typical AD value. When the overall signal acquired by the signal acquisition circuit at the controller MCU AD terminal does not reach the set AD typical value ±5% requirement, the emission adjustment signal circuit intervenes to adjust. The controller MCU compares each signal with the AD typical value. When the signal is stronger than the AD typical value, the MCU controls the emission adjustment signal circuit to reduce the current operating current of the emitting diode LED1. When the signal is weaker than the AD typical value, the controller MCU controls the emission adjustment signal circuit to increase the current operating current of the emitting diode LED1. After fine-tuning each signal, the overall infrared touch screen signal is made consistent, and the touch screen performance is optimal.

[0044] The working principle of this invention is as follows:

[0045] like Figures 1-3As shown, by setting up an operational amplifier adjustment circuit, multiple resistors R1...Rn with different resistance values ​​are connected in series on different channels of the multi-select switch S. The controller MCU controls the multi-select switch S to select different channels of resistors R1...Rn to adjust the operational amplifier amplification factor to adjust the received photoelectric signal, forming multiple controllable adjustment levels. At the same time, a third transistor Q3 is connected to the negative terminal of the emitting diode LED1. The controller MCU's DA terminal is used to drive the base voltage and current of the third transistor Q3 to control the operating current of the emitting diode LED1. Alternatively, the controller MCU's DA terminal is connected to the positive terminal of the emitting diode LED1 and the controller MCU's DA terminal is used to drive the base voltage and current of the third transistor Q3 to control the operating current of the emitting diode LED1.

[0046] like Figure 7 As shown, the control method is as follows: first, a typical AD value Vr_Typ is set in the infrared touch screen software. When the signal difference collected by the MCU is large, the controller MCU controls the multi-select switch S to select resistors R1...Rn of different channels to adjust the operational amplifier amplification factor to adjust the received photoelectric signal, so that the overall signal of the infrared touch screen is close to the typical AD value Vr_Typ. At this time, the signal still does not meet the requirements. Then, the controller MCU controls the third transistor Q3 to adjust the working current of the emitting diode LED1 through the DA terminal. Each signal is compared and finely adjusted to make the overall signal of the infrared touch screen meet the requirements of the typical AD value Vr_Typ.

[0047] The two signal adjustment methods and their circuits mentioned above have the advantages of multiple adjustment levels, wide adjustment signal range, and flexible control methods. They can solve problems such as signal consistency for different sizes of infrared touch screens, universality of circuit parameters, R&D efficiency, production convenience, and effective reduction of production costs.

[0048] In summary, a dimming circuit and its control method for infrared touchscreens were designed. By combining transmit and receive modulation, the signal amplitude is controlled within ±5%, achieving signal consistency for the infrared touchscreen. The combination of transmit modulation circuit and operational amplifier modulation circuit provides multiple modulation levels and a wide modulation signal range. This enables infrared touchscreens of different sizes to achieve overall signal consistency using the same circuit parameters, improving production and R&D efficiency and reducing production costs.

[0049] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0050] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, article, or apparatus that includes that element.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A dimming circuit for an infrared touchscreen, characterized in that, The system includes a controller, a transmitting component, a receiving component, a transmitting modulation signal circuit, a receiving operational amplifier modulation circuit, an operational amplifier modulation and amplification circuit, and a signal acquisition circuit. The signal output terminal of the controller is connected to the signal input terminals of the transmitting component, the receiving component, the transmitting modulation signal circuit, and the operational amplifier modulation and amplification circuit, respectively. The light emitted by the transmitting component is received by the receiving component. The input terminal of the receiving operational amplifier modulation circuit is connected to the signal output terminal of the receiving component and the signal output terminal of the operational amplifier modulation and amplification circuit, respectively. The signal acquisition circuit is used to acquire the signal from the receiving operational amplifier modulation circuit. The operational amplifier adjustment and amplification circuit includes a multi-select switch and multiple resistors with different resistance values ​​connected in series on different channels of the multi-select switch. The controller controls the multi-select switch to select resistors from different channels to adjust the operational amplifier amplification factor in order to adjust the received photoelectric signal. The transmitting component includes a transmitting diode, and the transmitting adjustment signal circuit includes a third transistor connected in series with the positive or negative terminal of the transmitting diode. The third transistor is used by the DA terminal of the controller to control the base voltage and current of the third transistor to adjust the power of the transmitting diode.

2. The dimming circuit for an infrared touchscreen according to claim 1, characterized in that, The transmitting component also includes a transmitting control circuit, wherein the signal output terminal of the controller is connected in series with the transmitting control circuit and the transmitting diode, and the signal output terminal of the transmitting adjustment signal circuit is connected to the signal input terminal of the transmitting diode. The receiving component includes a receiving control circuit and a receiving diode. The signal output terminal of the controller is connected in series with the receiving control circuit and the receiving diode. The light emitted by the emitting diode is received by the receiving diode. The signal output terminal of the receiving diode is connected to the signal input terminal of the receiving operational amplifier adjustment circuit.

3. A dimming circuit for an infrared touchscreen according to claim 2, characterized in that, The receiving operational amplifier adjustment circuit includes a first amplifier and a second amplifier. The signal input terminal of the first amplifier is connected to the signal output terminal of the receiving diode, and the signal output terminal of the first amplifier is connected in series with the second amplifier and then connected to the AD terminal of the controller.

4. A control method for the dimming circuit as described in any one of claims 1-3, characterized in that, This method is implemented according to the following steps: S1, the controller sets a typical value for AD, and the controller controls the operational amplifier adjustment circuit through the I / O terminal to make the received signal value close to the typical value of AD; S2 adjusts the voltage and current of the base of the third transistor through the DA terminal of the controller, and adjusts the current of the emitting diode. The AD value of the controller AD terminal acquired by the signal acquisition circuit is within ±5% of the typical AD value, that is, the signal value is consistent.

5. The control method for a dimming circuit of an infrared touchscreen according to claim 4, characterized in that, According to step S1, the controller controls the multi-select switch in the operational amplifier adjustment circuit to select resistors with different resistance values ​​for range adjustment, so as to adjust the overall received signal value to be close to the typical AD value.

6. The control method for a dimming circuit of an infrared touchscreen according to claim 5, characterized in that, According to step S2, when the signal acquisition circuit detects that the overall signal at the controller's AD terminal does not meet the set AD typical value ±5% requirement, the transmission adjustment signal circuit intervenes for adjustment. The controller compares each signal with the AD typical value. When the signal is stronger than the AD typical value, the controller controls the transmission adjustment signal circuit to reduce the current operating current of the current transmitting diode. When the signal is weaker than the AD typical value, the controller controls the transmission adjustment signal circuit to increase the current operating current of the current transmitting diode. After fine-tuning each signal, the overall infrared touch screen signal becomes consistent.

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