CN100550634C - A kind of control board transducer and display device - Google Patents

Abstract

The present invention is applicable to the capacitive sensing field, a kind of control board transducer is provided, described control board transducer comprises a capacitive induction button, and be connected with described capacitive induction button, detect the capacitance detector of its capacitance variations, described capacitive induction button comprises two copper sheets, a copper sheet ground connection wherein, form an electric capacity between the described copper sheet, be coated with insulating barrier on the described copper sheet, described insulating barrier is provided with an induction antenna, forms an electric capacity respectively between described induction antenna and two copper sheets.Described equipment comprises that one is used for the control board transducer of function button control and power button control.In the present invention,, strengthened the sensitivity of control board transducer, thereby reduced the distance of reaction between control board transducer and the conductor by increasing by an induction antenna.Utilize this control board transducer simultaneously, realized that no touch on tv product and display product is by key control.

Description

A control board sensor and display device

technical field

The invention belongs to the field of capacitive sensing, in particular to a control panel sensor and a display device.

Background technique

The principle of the capacitive sensing button is as follows: the capacitive sensing button is generally a pair of adjacent electrodes, and there is a small capacitance between the adjacent electrodes, which is called parasitic capacitance. When a conductor, such as a finger or a human body, approaches the capacitive sensing key, the conductive surface area of the adjacent electrode will be increased, thereby generating an additional capacitance between the electrode and the conductor. Whether the capacitive sensing key is pressed is determined by detecting the capacitance change between the electrode and the conductor by the capacitive detector. The advantage of the capacitive sensing key is that it has good durability, is not easy to be damaged, and realizes touchless control of the key. The disadvantage is that it is difficult to control the coverage thickness, and the sensitivity of capacitive sensing is not high enough.

At the same time, because the capacitive sensing button has the above shortcomings, it has not been applied in television products and display products. In the current TV products and display products, the switch buttons and function buttons all adopt ordinary mechanical buttons, and the power switch and function selection are realized by pressing the buttons with fingers. At present, new key technologies such as tact switches have also appeared, but as mechanical switches, their inherent problems such as feel and life have not been fundamentally resolved. When mechanical buttons are in use, not only the pressure on the buttons will affect their sensitivity, but also the clicking sound of the buttons will bring unnecessary noise to consumers and affect consumers' hearing experience. At the same time, it will affect the display products And the overall aesthetics of TV products will be affected.

Contents of the invention

The purpose of the present invention is to provide a control board sensor, aiming at solving the problems of low capacitive sensing sensitivity and difficult control of covering thickness existing in the prior art;

Another object of the present invention is to provide a display device.

The present invention is achieved in this way, a control board sensor, the sensor includes a capacitive sensing key, and a capacitive detector connected to the capacitive sensing key to detect its capacitance change, and the capacitive sensing key includes two A copper sheet, wherein one copper sheet is grounded, a capacitor is formed between the two copper sheets, an insulating layer is plated on the two copper sheets, an induction antenna is arranged on the insulation layer, and the induction antenna is connected to the insulating layer. A capacitance is respectively formed between the two copper sheets, and the capacitance detector includes a capacitance switch, a charging power supply, a comparator, a reset switch, a pulse width modulator and a timer, the charging power supply, the comparator And the reset switch forms a relaxation oscillator, and the relaxation oscillator continuously charges and discharges the sensor on the control board.

The induction antenna is a conductive sponge.

A display device, the device includes a control board sensor, the control board sensor includes a capacitive sensing button, and a capacitive detector connected to the capacitive sensing button to detect its capacitance change, the capacitive sensing The button includes two copper sheets, one of which is grounded, a capacitor is formed between the two copper sheets, an insulating layer is plated on the two copper sheets, and an induction antenna is arranged on the insulating layer. A capacitance is respectively formed between the induction antenna and the two copper sheets, and the capacitance detector includes a capacitance switch, a charging power supply, a comparator, a reset switch, a pulse width modulator and a timer, and the charging power supply , a comparator and a reset switch form a relaxation oscillator, and the relaxation oscillator continuously charges and discharges the electrodes of the control board sensor.

The induction antenna is a conductive sponge.

The display device is a monitor or a television.

In the present invention, by adding an induction antenna to the control panel sensor, the sensitivity of the control panel sensor is enhanced, thereby reducing the sensing distance between the capacitive sensing button and the conductor. At the same time, the touchless control of function keys and switch keys on various television products and display products is realized by using the control board sensor provided by the invention.

Description of drawings

Fig. 1 is the circuit schematic diagram of the capacitive sensing button of the control board sensor of the present invention;

Fig. 2 is the composition structural diagram of the capacitive detector of control panel sensor of the present invention;

Fig. 3 is the hardware structural diagram of the display that utilizes control panel sensor of the present invention;

Fig. 4 is a module composition diagram of the specific implementation of the control board sensor on the display in the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

In the present invention, by adding an insulating layer on the copper sheet of the capacitive sensing key constituting the control panel sensor, and adding an induction antenna on the insulating layer, the sensitivity of the capacitive sensing key is increased, thereby reducing the impact of the covering thickness on the capacitive sensing The effect of keystrokes. At the same time, in the present invention, the touchless control of function buttons and switch buttons on various television products and display products is realized by using the control panel sensor.

The control panel sensor of the present invention includes at least one capacitive sensing key and a capacitive detector connected with the capacitive sensing key.

Figure 1 shows the structure of the capacitive sensing button, which is described in detail as follows:

The capacitive sensing button includes two copper sheets 1 , one of which is grounded, and a capacitance is formed between the two copper sheets 1 . Assume that the total capacitance value between the copper sheet 1 and the ground is C _P . When the capacitive sensing button is not pressed, a parasitic capacitance C _Y is formed between the copper sheet 1 and the ground, and at this time, C _P =C _Y . When a conductive element 3 (the conductive element can be a finger, a human body, etc.) is close to the capacitive sensing button, according to the sensing principle of the capacitive sensing technology, an additional capacitance C _X will be generated, so that the total distance between the copper sheet and the ground The value of capacitance C _P increases, and at this time C _P =C _Y +C _X . Copper skin 1 is plated with a layer of drain oil as an insulating layer, and an induction antenna 5 with a sensing function is provided on the insulation layer. The induction antenna can be a conductive sponge, which has strong conductivity and can enhance the capacitive induction button. Sensitivity, reduce the sensing distance between the capacitive sensing button and the conductor. A glass layer 7 is covered on the sensing antenna 5 to protect the capacitive sensing key. Due to the increased sensitivity of capacitive sensing keys, the thickness of this glass layer is relatively easy to control. Whether the capacitive sensing key is pressed can be determined by detecting the capacitance change of the capacitive sensing key by the capacitance detector.

Figure 2 shows the composition of a capacitive detector, detailed below:

The capacitance detector is used to detect the capacitance change of the capacitive sensing key to determine whether a key is pressed. The capacitance detector includes a capacitance switch, a charging power supply, a comparator, a reset switch, a pulse width modulator (PWM) and a timer. Wherein the capacitive switch is connected with the capacitive sensing key, and the electrode capacitance of the capacitive sensing key is continuously charged and discharged through a relaxation oscillator composed of a comparator, a charging power supply and a reset switch. At the same time, a capacitor charging threshold V _TH is set in the comparator, the output of the comparator is sent to the clock input circuit of the PWM, the output of the PWM is connected to the capture pin of the timer, and the output of the PWM will enable a timer. When the charging capacitor reaches the capacitor charging threshold V _TH , the count value (n) of the timer is calculated. The count value (n) of the timer is the number of times the capacitor is charged and discharged when the charging and discharging capacitor reaches the capacitor charging threshold V _TH .

The count value (n) of the timer can be associated with a specific threshold. When the count value of the timer is less than the specific threshold value, it is considered that the capacitive sensing key is pressed, otherwise it is considered not to be pressed.

The determination of the specific threshold value is related to the environment where the display is located and the sensing sensitivity of the capacitive sensing key. For example: Assume that when the capacitive sensing button is not pressed and the charging and discharging voltage reaches V _TH , the count value of the timer is n1; when the capacitive sensing button is approached by a conductor and the charging and discharging voltage reaches V _TH , the timer counts The value is n2. In principle, as long as the value of n2 is smaller than the value of n1 at this time, it can be considered that the capacitive sensing button is pressed. However, the capacitive sensing button is easily affected by the environment. When the temperature or humidity of the environment where the display is located increases, the capacitance of the capacitive sensing button may be increased, so that when there is no conductor close, the capacitance bridge charge conversion detection method can also judge A button is pressed, resulting in an operation error. Therefore, in the method for detecting the charge conversion of the capacitor bridge, by setting a specific threshold value, judgment errors caused by capacitance changes caused by environmental changes are avoided. The switch is considered to be pressed only when the value of n is less than this particular threshold.

When the sensitivity of the capacitive sensing key increases, the setting of the specific threshold value can also be correspondingly increased, thereby increasing the sensing distance between the capacitive sensing key and the conductor. Its specific size can be determined through multiple tests according to the coverage thickness and sensitivity of the capacitive sensing key. Since the greater the distance between the conductor and the capacitive sensing key, the lower the sensitivity of the sensing switch, only when a relatively small threshold value is set, can the correct sensing of the sensing capacitive switch be ensured.

In the present invention, by adding a conductive sponge on the electrode of the capacitive sensing key, the conductive sponge can increase the sensitivity of the capacitive sensing key, thereby determining a relatively large specific threshold value, increasing the conductor and capacitive sensing Sensing distance between keys.

Fig. 3 shows the hardware circuit structure of the application of the control board sensor on the display of the present invention.

Because the system on a PSoC chip contains 8 digital blocks and 12 analog blocks. Users can define the functions required by users by configuring these modules. For example: digital modules can be configured as timers, counters, serial communication ports (UARTS), CRC generators, PWM and other functional modules; analog modules can be configured as analog-to-digital converters, digital-to-analog converters, programmable gain amplifiers, Program filters, differential comparators and other functional modules. Digital modules and analog modules can also constitute modems, complex motor controllers, sensor signal processing circuits, etc.

In the present invention, by configuring the internal hardware of the PSoC chip CY8C21534, it is configured as a capacitance detector to form a control board sensor. The configured CY8C21534 chip cyclically detects the state of the electrode of the capacitive sensing button to determine whether a button is pressed. The CY8C21534 chip is connected to the burner through the software burn-in socket to configure the internal hardware of the CY8C21534 IC chip. Its specific configuration is as follows: the comparator occupies an analog module, and its non-inverting input terminal multi-channel analog switch is connected to the capacitive sensing button through the I/O interface, and its inverting input terminal is connected to the internal reference voltage as the capacitor charging threshold V _TH for Compare with the voltage at the input. The output of the comparator is sent to the clock input circuit of the pulse width modulator (PWM). The PWM pulse width modulation module occupies a digital module, its clock input is connected to the output of the comparator, and the output of the PWM is connected to the capture pin of the timer. A 16-bit timer occupies 2 digital modules, timing the pulse output by PWM, and calculates the count value (n) of the timer.

As a specific embodiment of the present invention, five capacitive sensing buttons are set on the display, namely: Menu capacitive sensing button, Auto capacitive sensing button, On/Of capacitive sensing button, "-" capacitive sensing The button and the "+" capacitive sensing button are used to adjust the display. Each capacitive sensing button is respectively connected to the corresponding pin of the CY8C21534 chip through wires.

After configuration, the PSoC chip CY8C21534 detects that the capacitive sensing button is pressed, connects with the control unit (LCD-MCU) of the display through the connection socket of the display control unit, and sends the detection result to the LCD-MCU. When the display is in the working state, the LCD-MCU controls the display to respond to the operation of the corresponding capacitive sensing button according to the detection result of the CY8C21534 chip, and sends an instruction to the buzzer, and the buzzer sounds to prompt. At the same time, the CY8C21534 chip provides the working voltage for the corresponding sensor indicator light, and the LED light corresponding to the pressed capacitive sensor button is displayed.

As mentioned above, in the present invention, by adding a sensing antenna on the capacitive sensing key, the sensitivity of the capacitive sensing key is enhanced, and by configuring the PSoC chip CY8C21534 as the control board sensor for detecting the capacitive sensing key The capacitive detector for capacitance change makes the control panel sensor applied to the display product, and the application principle of the control panel sensor to the TV product is similar to the above, and will not be repeated here.

Fig. 4 shows the module composition of the concrete realization of the application of control board sensor of the present invention on the display, detailed description is as follows:

When the display is in working state, that is, when the display is not turned off, the working power supply module 31 provides the working voltage for the capacitance detector module 32 and the LCD-MCU module 33 at the same time, and the capacitance detector here can be a CY8C21534 chip, so that the capacitance detector The module and the LCD-MCU module can communicate with each other to realize the operation of the capacitive sensing button on the display. At the same time, the LCD-MCU module 33 controls the on and off of the power indicator light in the power indicator light control module 36 according to the voltage provided by the working power supply module 31 . When the conductor is close to the induction control module 34, according to the principle of capacitive induction, the special IC module 32 detects the presence of the conductor, and the special IC module 32 sends an instruction to the induction indicator light control module 35, and provides it with an operating voltage at the same time, so that it is compatible with the capacitive type. The sensor indicator corresponding to the sensor button is on. Simultaneously capacitance detector module 32 sends instruction to LCD-MCU module 33, the voltage of LCD-MCU module 33 is reduced, and LCD-MCU module 33 detects the voltage change of itself, and judgment switch is pressed, and buzzer control module 37 gives instructions, and the buzzer sounds to prompt.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (5)

1, a kind of control board transducer, it is characterized in that, described transducer comprises a capacitive induction button, and be connected with described capacitive induction button, detect the capacitance detector of its capacitance variations, described capacitive induction button comprises two copper sheets, a copper sheet ground connection wherein, form an electric capacity between described two copper sheets, be coated with insulating barrier on described two copper sheets, described insulating barrier is provided with an induction antenna, form an electric capacity respectively between described induction antenna and two copper sheets, described capacitance detector comprises a capacitance switch, one charge power supply, one comparator, one reset switch, one pulse-width modulator and a timer, described charge power supply, comparator and reset switch are formed a relaxation oscillator, and described relaxation oscillator continues to discharge and recharge to described control board transducer.

2, control board transducer as claimed in claim 1 is characterized in that, described induction antenna is a conductive sponge.

3, a kind of display device, it is characterized in that, described equipment comprises a control board transducer, described control board transducer comprises a capacitive induction button, and be connected with described capacitive induction button, detect the capacitance detector of its capacitance variations, described capacitive induction button comprises two copper sheets, a copper sheet ground connection wherein, form an electric capacity between described two copper sheets, be coated with insulating barrier on described two copper sheets, described insulating barrier is provided with an induction antenna, form an electric capacity respectively between described induction antenna and two copper sheets, described capacitance detector comprises a capacitance switch, one charge power supply, one comparator, one reset switch, one pulse-width modulator and a timer, described charge power supply, comparator and reset switch are formed a relaxation oscillator, and described relaxation oscillator continues to discharge and recharge to the electrode of described control board transducer.

4, display device as claimed in claim 3 is characterized in that, described induction antenna is a conductive sponge.

5, display device as claimed in claim 3 is characterized in that, described display device is display or television set.

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