A display screen of a home appliance implementing multi-cell touch control

Abstract

The utility model discloses a kind of home appliance display screen of realizing multi-unit touch control, including circuit board, support, light barrier layer, diaphragm and panel arranged in sequence, the position corresponding to touch display unit is set on circuit board touch sensing area, the air layer formed between touch point position and touch sensing area through the lamp cavity opened in support formed by touch sensing area on circuit board, lamp cavity, diaphragm touch display unit, the thickness 2mm of air layer is L≤5mm, LED lamp pearl is set in touch sensing area, microcontroller and its peripheral circuit for processing touch signal are set on circuit board. The utility model dispenses with the setting of light guide plate, touch sensing area is set on circuit board, both save material cost, also reduce process step. Special design LED lamp pearl is used, reduce the use quantity of lamp pearl in same touch electrode area, reduce noise, improve signal amount, realize larger interval's spaced touch.

Description

Technical Field

[0001] This utility model belongs to the field of touch display technology, specifically relating to a home appliance display screen that realizes multi-unit touch control. Background Technology

[0002] When a display screen has multiple touch units, the signals between the touch units will affect each other. When the system has low sensitivity to touch signal detection, the mutual influence is weak. However, when the system has high sensitivity to touch signal detection, touching one unit will affect other units.

[0003] Chinese utility model patent CN118170274A discloses a doorless touch display system for a household refrigerator, comprising a circuit control unit and an auxiliary structural unit. The auxiliary structural unit is mounted on the circuit control unit via adhesive bonding. When a touch button is pressed, the corresponding touch-sensitive PAD acquires the touch signal. The acquired touch signal is fed back to a touch chip via a control circuit etched on a PCB substrate. The touch chip detects and analyzes the touch signal and generates a corresponding touch display scheme result. The display scheme result is sent to an LED display unit electrically connected to the PCB substrate for display. This doorless touch display system uses a frame to create a gap between the touch panel and the PCB substrate, and utilizes the touch display scheme result built into the control chip, replacing traditional touch display methods such as springs and rubber rings. Existing doorless touch methods require a very small gap to meet sensitivity requirements; increasing the air gap makes accurate touch signal acquisition impossible. Furthermore, it cannot solve the problem of signal interference and mutual influence between multiple adjacent units. Utility Model Content

[0004] The technical problem solved by this utility model is to provide a home appliance display screen that improves the touch sensitivity of an array-type multi-touch unit display system and reduces the mutual interference of signals between adjacent touch units, thereby enabling multi-unit touch control.

[0005] Technical solution: To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0006] A home appliance display screen for multi-unit touch control includes a circuit board, a bracket, a light-blocking layer, a film, and a panel arranged sequentially. A touch-sensing area is set at the position corresponding to the touch display unit on the circuit board. The touch-sensing area on the circuit board, the lamp cavity opened on the bracket, and the film form the touch display unit. An air layer formed by the lamp cavity opened on the bracket passes between the touch point and the touch-sensing area. The thickness of the air layer is 2mm < L < 10mm. LED beads are set in the touch-sensing area. A microcontroller for processing touch signals and its peripheral circuits are set on the circuit board.

[0007] Furthermore, the electrode pads of the touch sensing area are disposed on the circuit board and are correspondingly disposed in the lamp cavity of each touch display unit.

[0008] Furthermore, the LED beads are disposed on the circuit board inside the lamp cavity; the LED beads are bottom-emitting light sources, and the LED beads are disposed corresponding to the touch sensing area.

[0009] Furthermore, the LED beads are surface-mount LEDs with an average light intensity diffusion angle of 150°~175°.

[0010] Furthermore, the height of the lamp cavity is less than or equal to the length and width of the touch sensing area, and the interval between adjacent touch sensing areas is greater than or equal to the height of the lamp cavity.

[0011] Furthermore, the circuit board is disposed on the back of the bracket, and a sealant layer is disposed on the back of the circuit board.

[0012] Furthermore, the light-blocking layer is a black foam disposed between the film and the support, and the black foam is located on the outer periphery of the lamp cavity, blocking the light between adjacent touch display units.

[0013] Furthermore, the panel is 3mm thick, the distance between the touch position on the upper surface of the panel and the electrode plate of the touch sensing area is 5~8mm, the display unit composed of the circuit board, bracket, light blocking layer and film is set inside the panel, and the panel is mounted on the front control bracket.

[0014] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0015] (1) The home appliance display screen of this utility model that realizes multi-unit touch control can eliminate the need for a light guide plate. The touch sensing area is set on the circuit board, which eliminates the need to set the touch sensing area on the film as in the existing lamp cavity type display screen structure. This saves material costs and reduces process steps.

[0016] (2) The home appliance display screen of this utility model that realizes multi-unit touch control uses a circuit composed of signal processing chips, which can improve the signal quantity and reduce noise. It meets the signal acquisition and processing requirements of array-type adjacent touch units and reduces signal interference between adjacent touch display units. It can reduce the noise of the overall circuit to 1 / 6 of that in the prior art, realize air-to-air touch with a larger spacing, and meet the requirements of signal sensitivity.

[0017] (3) The home appliance display screen of this utility model that realizes multi-unit touch control adopts specially designed LED beads, which reduces the number of beads used in the same touch electrode area, reduces the influence of the beads on the touch sensing area, reduces noise, and increases the signal quantity. Attached Figure Description

[0018] Figure 1 This is an exploded view of a multi-unit touch system with air contact.

[0019] Figure 2 This is a schematic diagram of a multi-unit touch system bracket.

[0020] Figure 3 This is a schematic diagram of the circuit board for a multi-unit touch system with air contact.

[0021] Figure 4 This is a schematic diagram of the touch mode of a multi-unit touch system with air contact.

[0022] Figure 5 Schematic diagram of the touch structure of a multi-unit touch system with air contact;

[0023] Figure 6 Schematic diagram of a multi-unit touch system;

[0024] Figure 7 Schematic diagram of signal processing circuit for a multi-unit touch system;

[0025] Figure 8 Circuit diagrams for different numbers of LED beads;

[0026] Figure 9 Circuit diagrams showing different numbers of LED beads;

[0027] Figure 10 Noise results for setting a single LED bead in the touch sensing area;

[0028] Figure 11 Noise results for setting three LED beads in the touch sensing area;

[0029] Figure 12 The noise results are compared between having one and three LED beads in the touch sensing area;

[0030] Figure 13 These are the parameters of the LED beads used in this utility model;

[0031] Figure 14 This utility model describes the circuit principle of a home appliance display screen that implements multi-unit touch control. Figure 1 ;

[0032] Figure 15 This utility model describes the circuit principle of a home appliance display screen that implements multi-unit touch control. Figure 2 ;

[0033] Figure 16 This utility model describes the circuit principle of a home appliance display screen that implements multi-unit touch control. Figure 3 ; Detailed Implementation

[0034] The present invention will be further illustrated below with reference to specific embodiments. The embodiments are implemented on the premise of the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0035] like Figure 1 As shown, the home appliance display screen for multi-unit touch control in this embodiment includes a circuit board 1, a bracket 2, a light-blocking layer 3, a film 4, a touch sensing area 5, a lamp cavity 21, an air layer 22, LED beads 23, a sealant layer 8, a front control bracket 7, and a microcontroller and its peripheral circuits.

[0036] like Figure 1 The diagram shown is an exploded view of a home appliance display screen that implements multi-unit touch control. Circuit board 1, bracket 2, light-blocking layer 3, and film 4 are arranged sequentially. A touch sensing area 5 is set at the position corresponding to the touch display unit on circuit board 1. The touch sensing area 5 on circuit board 1, the lamp cavity 21 opened on bracket 2, and film 4 form a touch display unit. An air layer 22, formed by the lamp cavity 21 opened on bracket 2, passes between the touch point and the touch sensing area 5. The thickness of the air layer 22 is less than 10mm and greater than 2mm. The display system has multiple adjacent touch display units. The microcontroller and its peripheral circuits receive the touch signals from the touch sensing area 5 and process the signals. Under high-sensitivity touch signal recognition, signal interference from adjacent touch display units is eliminated, and the touch signal of the predetermined target touch display unit is accurately identified.

[0037] Preferably, the thickness of the air layer is 3mm to 5mm, and the thickness of the film and panel 6 above the air layer is about 3mm. Therefore, the distance between the touch position and the touch sensing area 5 can achieve a touch distance of 6-8mm (touch distance threshold).

[0038] The height of the lamp cavity 21 is less than or equal to the length and width of the touch sensing area 5, and the interval between adjacent touch sensing areas 5 is greater than or equal to the height of the lamp cavity 21.

[0039] Touch sensing areas 5 are disposed on the circuit board 1 and are correspondingly disposed in the lamp cavity 21 of each touch display unit. In this embodiment, there are multiple lamp cavities 21 arranged in a matrix. The lamp cavity in the middle is surrounded by adjacent lamp cavities and touch sensing areas on all sides. When a touch signal is received, the adjacent touch sensing areas will also receive the touch signal, thereby interfering with the touch sensing area of ​​the predetermined target.

[0040] like Figure 3 As shown, the touch display unit also includes LED beads 23, which are disposed on the circuit board 1 inside the lamp cavity 21. The LED beads 23 are bottom-emitting light sources, and the LED beads 23 are correspondingly disposed with the touch sensing area 5.

[0041] In this invention, the LED beads are set in the touch sensing area. In order to reduce the influence of the LED beads on the sensing signal of the touch sensing area, the fewer the number of LED beads set in the touch sensing area 5, the better, and the smaller the area occupied by the LED beads, the better.

[0042] Because the size of the touch-sensing area varies, the number of LED beads in each area also varies. In actual use, one, two, or more LEDs can be used to achieve uniform light and meet the required brightness. Figure 8 and 9 As shown, touch sensing areas 5 have different numbers of LED beads. For touch sensing areas of the same size, the effect of deploying one LED bead versus multiple LED beads on the touch signal is different. In this implementation, we take deploying one LED bead and three LED beads as examples for comparison and compare the noise values ​​of the two.

[0043] The signal noise of the touch sensing area was tested for single LED beads and three LED beads, and the results are as follows: Figure 10-12 As shown, Figure 10 The noise level for setting a single LED bead in the touch sensing area was 32. Figure 11 The noise level is 66, which is the result of setting three LED beads in the touch sensing area. Figure 12 This is a comparison of noise results when the touch sensing area has one and three LED beads. It can be seen that the fewer the number of LED beads, the lower the noise and the less impact it has on the touch signal.

[0044] To reduce the number of LED chips, minimize their impact on touch signals, lower noise, and achieve both light intensity and uniformity despite the reduced number of chips, this invention employs specially designed LED chips. In this embodiment, the LED chips are surface-mount LEDs with an average light intensity diffusion angle of 150°~170°. In the prior art, the average light intensity diffusion angle of conventional LED chips is less than 120 degrees. This invention specially designs the LED chips to achieve an average light intensity diffusion angle greater than 150°. This reduces the number of LED chips used in the same area of ​​the touch sensing area 5, while achieving uniform light and light intensity that meets design requirements, and satisfying the LED light path requirements within the limited height of the lamp cavity.

[0045] like Figure 13 The figure shows the parameters of the LED beads used in this embodiment. Using LED beads with these parameters results in a large light diffusion range, effectively reducing the number of LED beads required and significantly decreasing touch signal noise.

[0046] Circuit board 1 is mounted on the back of bracket 2, and a sealant layer 8 is applied to the back of circuit board 1. A waterproof layer is formed by potting the sealant, which is then evenly applied to the back of the circuit board to a thickness of approximately 3mm to 5mm. The waterproof sealant may be polyurethane sealant or silicone, etc. Alternatively, a sealing ring can be used to prevent water from entering the circuit board from appliances near water sources, such as washing machines, and thus affecting its normal operation.

[0047] The thickness of the membrane 4 is 0.1mm~0.5mm. The base film of the membrane 4 can be PET or PC film. A graphic layer is set and printed on the PET or PC film. The membrane can be a colored film to realize the display of icons and text with multiple functions, and can display background patterns with a sense of design.

[0048] The light-blocking layer 3 is a black foam disposed between the film 4 and the bracket 2. The black foam is located on the outer periphery of the lamp cavity 21, blocking the light between adjacent touch display units. The black foam also serves as a filler, filling the gap between the film and the bracket. Furthermore, the foam layer acts as an adhesive medium, bonding the film to the bracket and preventing the film from not adhering tightly to the rigid bracket.

[0049] The display system also includes a panel 6. A display unit consisting of a circuit board 1, a bracket 2, a light-blocking layer 3, and a film 4 is disposed within the panel 6. The panel 6 is mounted on a front control bracket 7. A display window is provided on the panel 6. The display window is made of acrylic, glass, in-mold molding (IMD), or other injection molded parts (using ABS, PC, or ABS+PC materials). The display window can clearly display the content of the screen, and the touch display unit can be controlled by touch through the acrylic or glass panel.

[0050] like Figure 6 The diagram shown is a schematic of the principle of a finger touching the touch sensing area, where C F It's a finger capacitor, C p It's parasitic capacitance, the sensor capacitance in a capacitive sensing system when there's no finger present. When a finger approaches or touches the sensor, the sensor capacitance changes, which generates a capacitance similar to C. p The other capacitor connected in parallel is called the finger capacitor C. F When a finger is present, the total sensor capacitance Cs is as shown in the following formula:

[0051] Cs=C p +C F ;

[0052] However, when multiple touch sensing areas are arranged in an array, when a finger touches one touch sensing area, adjacent sensing pads will also generate signals, interfering with the intended touch sensing area. This interference is particularly pronounced on adjacent touch sensing areas near the palm. To address this issue, this embodiment employs the following signal processing circuitry to weaken interference signals and noise, accurately selecting the signal for the intended touch sensing area.

[0053] like Figure 14-16 The diagram shown is a circuit schematic of a touch control unit for a home appliance. Figure 14 The circuit diagram shown is for controlling touch signals and LED beads, including a microcontroller and peripheral circuits (button input module, communication interface, power supply and reset circuit, etc.). The microcontroller uses the CY8C4147AZI series microcontroller chip: the microcontroller is the control center of the circuit, and all peripherals are connected to its pins to realize signal input / output, communication, control and other functions.

[0054] The +5V power supply is connected to the VSSA and VSSD pins of the microcontroller via filter capacitors C2 and C3 to power the chip. The +5V is connected to the XRES pin via resistor R10, which, together with capacitor C7, forms a reset circuit to achieve system power-on reset or manual reset.

[0055] The key input module mainly handles the touch control input signals of this invention. Multiple touch control keys (SW1~SW32) are connected to the GPIO pins (P0.0~P0.7, P2.0~P2.7, etc.) of the microcontroller through resistors. When a touch signal is received, the key is activated, the corresponding pin level changes, and the microcontroller can detect the key input.

[0056] The LED Driver_SDA and LED Driver_SCL pins are connected to an external LED to drive external LED devices. The SPI_MISO, SPI_MOSI, and SPI_SCK pins are used for SPI protocol communication.

[0057] like Figure 7 The diagram shown is a schematic of the signal processing circuit in this embodiment. The total capacitance of the sensor is processed. The signal processing circuit removes the reference and converts it to a differential form.

[0058] The signal processing circuit includes the sensor capacitor C. s The first set of switches swph0 and swph1, the second set of switches swph2 and swph3, and the external capacitor C. MOD1 External capacitor C MOD2 Reference capacitor C ref And a Σ-Δ converter, wherein the Σ-Δ converter includes a comparator and an N-bit counter. Sensor capacitance C sOne end is grounded, and the other end is connected to C via switch swph1. MOD1 Connection, simultaneously via swph1 and C MOD1 Grounding; C MOD2 One end is connected to the total sensor capacitance C via swph3. s Connect one end to the ground; C MOD1 One end is connected to the inverting input of the comparator, and the non-inverting input of the converter is connected via C. MOD2 Ground; Reference capacitor C ref The internal switches of the converter form a feedback loop, with reference capacitor C. ref The comparator's non-inverting input is connected via a switch, and its inverting input is also connected via a switch. The comparator's output forms a feedback circuit via a reference capacitor and a switch. A counter is used to count the output pulses. The final output is Raw Count.

[0059] ;

[0060] Where Raw Count represents the raw count, Cs represents the total sensor capacitance, and C ref This represents the reference capacitance, and α is a proportional sign, which can also be understood as a coefficient.

[0061] Figure 7 The working principle of the signal processing circuit shown:

[0062] External capacitor C MOD1 and external capacitor C MOD2 During initialization, precharge to Vdda / 2.

[0063] Step 1: Turn off swph0, short Cs and vdda, and charge Cs to vdda.

[0064] Step 2: Open swph0, close swph1, Cs and C MOD1 Short circuit, C MOD1 The voltage will be boosted, exceeding vdda / 2, at which point C MOD1 Charge from precision capacitor array C ref Release, until C MOD1 Voltage to vdda / 2.

[0065] Step 3: Turn off swph2, short Cs and GND, and reduce the voltage of Cs to 0.

[0066] Step 4: Open swph2, close swph3, Cs and C MOD2 Short circuit, C MOD2 The voltage will be pulled down to less than vdda / 2, at which point the precision capacitor array C ref For C MOD2 Charge until CMOD2 Voltage to vdda / 2.

[0067] The value of Raw Count is used to calculate the time it takes for Raw Count charge to be released to vdda / 2, and C MOD2 The charging time is until vdda / 2. At this point, the only noise source is the comparator error, which eliminates at least two to three noise sources compared to conventional touch mechanisms in existing technologies. Therefore, the current touch sensitivity is higher, the noise is lower, and the anti-interference capability between multi-touch buttons is stronger.

[0068] The above are merely preferred embodiments of this utility model. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model.

Claims

1. A home appliance display screen that enables multi-unit touch control, characterized in that: The circuit includes a circuit board (1), a bracket (2), a light-blocking layer (3), a diaphragm (4), and a panel (6) arranged in sequence. A touch-sensing area (5) is set at the position corresponding to the touch display unit on the circuit board (1). The touch-sensing area (5) on the circuit board (1), the lamp cavity (21) opened on the bracket (2), and the diaphragm (4) form a touch display unit. An air layer (22) is formed between the touch point and the touch-sensing area (5) through the lamp cavity (21) opened on the bracket (2). The thickness of the air layer (22) is 2mm < L < 10mm. An LED lamp bead (23) is set in the touch-sensing area (5). A microcontroller and its peripheral circuits for processing touch signals are set on the circuit board (1).

2. The home appliance display screen for multi-unit touch control according to claim 1, characterized in that: The electrode plates of the touch sensing area (5) are disposed on the circuit board (1) and are respectively disposed in the lamp cavity (21) of each touch display unit.

3. The home appliance display screen for realizing multi-unit touch control according to claim 1, characterized in that: The LED beads (23) are disposed on the circuit board (1) inside the lamp cavity (21); the LED beads (23) are bottom-emitting light sources, and the LED beads (23) are disposed corresponding to the touch sensing area (5).

4. The home appliance display screen for realizing multi-unit touch control according to claim 1, characterized in that: The LED beads (23) are surface-mount LEDs with an average light intensity diffusion angle of 150°~175°.

5. The home appliance display screen for realizing multi-unit touch control according to claim 2, characterized in that: The height of the lamp cavity (21) is less than or equal to the length and width of the touch sensing area (5), and the interval between adjacent touch sensing areas (5) is greater than or equal to the height of the lamp cavity (21).

6. The home appliance display screen for realizing multi-unit touch control according to claim 1, characterized in that: The circuit board (1) is disposed on the back of the bracket (2), and a sealant layer (8) is disposed on the back of the circuit board (1).

7. The home appliance display screen for realizing multi-unit touch control according to claim 1, characterized in that: The light-blocking layer (3) is a black foam disposed between the diaphragm (4) and the bracket (2). The black foam is located on the outer periphery of the lamp cavity (21) and blocks the light between adjacent touch display units.

8. The home appliance display screen for realizing multi-unit touch control according to claim 1, characterized in that: The thickness of the panel (6) is 3mm. The distance between the touch position on the upper surface of the panel (6) and the electrode plate of the touch sensing area (5) is 5~8mm. The display unit composed of the circuit board (1), bracket (2), light blocking layer (3) and film (4) is set inside the panel (6). The panel (6) is mounted on the front control bracket (7).

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