Special-shaped ultra-thin display module and method for improving touch sensitivity of the module

Abstract

The present invention discloses a special-shaped ultra-thin display module and a method for improving the touch sensitivity of the module. The special-shaped ultra-thin display module has a bracket arranged between a circuit board and a diaphragm, the shape of the bracket is adapted to the shape of a cover plate, the bracket makes the special-shaped ultra-thin display module close to the special-shaped cover plate, and the bracket makes the distance between the touch keys of different display units of the special-shaped ultra-thin display module and the cover plate different, and the system processes the touch signals of different display units separately, respectively using different parameters to improve the resolution to obtain a suitable touch signal value. The bracket is used to fill the gap between the ultra-thin display module and the cover plate, which is more solid in structure, convenient to install, and can prevent the ultra-thin display module from deforming; the special-shaped ultra-thin display module is close to the outermost glass cover plate for touch, further improving the touch sensitivity and stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of display screens, and in particular relates to a special-shaped ultra-thin display module and a method for improving the touch sensitivity of the module. Background Art

[0002] The applicant disclosed an ultra-realistic ultra-thin display module in a Chinese invention patent with application number 2022235397721, entitled "An ultra-realistic ultra-thin display module," and the module has been put on the market. However, the product is only applicable to flat glass cover plates of home appliances. The glass of the cover plate shell of the home appliance is in close contact with the ultra-realistic ultra-thin display module to achieve high-sensitivity touch.

[0003] However, current display technology only allows a maximum distance of 5mm between the housing's glass cover and the touch-sensing device while ensuring normal touch sensitivity. Any distance exceeding 5mm will result in touch failure. For example, after installing an ultra-thin display module, the housing's glass is 3mm thick, and the module's light guide plate is 1.5mm thick, for a total spacing of 4.5mm. This spacing within 5mm ensures touch sensitivity, but any distance exceeding this distance will result in touch failure. Existing technology currently lacks a solution for larger touch distances.

[0004] The covers of home appliances on the market come in various shapes. Taking washing machines as an example, there are curved covers, stepped covers, and other forms. For example, when a curved display panel is installed with an ultra-realistic ultra-thin display module, a gap will form between the touch surface of the ultra-thin display module and the outer glass surface of the curved shell cover. This gap causes the distance between the curved glass surface of the shell cover and the ultra-thin display module to exceed 5 mm. In particular, the distance between the middle part of the curved glass and the ultra-thin display module is even greater, possibly reaching 10 mm or more, resulting in unstable touch. Summary of the Invention

[0005] Technical problem solved by the present invention: In order to solve the above-mentioned problem of large touch spacing, which leads to reduced touch sensitivity or even complete touch failure, the present invention provides a special-shaped ultra-thin display module suitable for an arc-shaped or special-shaped shell with a curved shell cover, which can ensure the touch spacing and improve touch sensitivity.

[0006] Technical solution: In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A special-shaped ultra-thin display module has a bracket disposed between a circuit board and a diaphragm. The bracket's shape is adapted to that of a cover plate, allowing the special-shaped ultra-thin display module to fit snugly against the special-shaped cover plate. The bracket also creates differences in the distances between touch buttons and the cover plate for different display units of the special-shaped ultra-thin display module. The system processes touch signals from different display units individually, using different parameters to improve resolution and obtain appropriate touch signal values.

[0008] Preferably, the special-shaped ultra-thin display module further includes a foam layer, and the foam layer is arranged between the diaphragm and the bracket.

[0009] Preferably, the upper end of the vertical cross-section of the bracket is arc-shaped or stepped.

[0010] Preferably, through display holes are provided on both the bracket and the diaphragm, and the positions and numbers of the display holes of the two correspond to the display units on the circuit board.

[0011] Preferably, a light guide plate is provided between the diaphragm and the circuit board, the position and number of the light guide plates correspond to the display units on the circuit board, and the light guide plates are provided in the display hole.

[0012] Preferably, the thickness of the light guide plate matches the thickness of the bracket.

[0013] A method for improving the touch sensitivity of special-shaped ultra-thin display modules utilizes the self-capacitance of the MSC touch sensor to receive finger touch signals. The capacitance signal is converted into a micro-current signal through a switching circuit. The current signal is converted into a digital signal as the original signal through analog-to-digital conversion, and then the original signal is filtered.

[0014] To cope with the key differences, the touch signals of different display units are processed separately, using different parameters and improving the resolution to obtain appropriate touch signal values.

[0015] Preferably, the filtering process is as follows: the original data is subjected to IIR filtering and median filtering to obtain a stable touch signal value. In order to resist external interference of the product, the touch signal will be subjected to sliding filtering again.

[0016] As a preferred option, the latest capacitive touch technology is used to become MSC (multi sense converter). Its main features include ratiometric sensing, differential mode, no need for reference voltage, and the use of capacitive DAC instead of current DAC to improve noise performance, achieving high signal output and a signal-to-noise ratio of more than 10 times.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0018] (1) The special-shaped ultra-thin display module of the present invention integrates the special-shaped bracket into the structure of the ultra-thin display module. The shape of the bracket matches the curved or other special-shaped display panel, filling the gap between the ultra-thin display module and the cover plate. The structure is more solid, easy to install, and can prevent the ultra-thin display module from deformation.

[0019] (2) The special-shaped ultra-thin display module of the present invention is in close contact with the outermost glass cover plate for touch, further improving touch sensitivity and stability.

[0020] (3) The bracket of the special-shaped ultra-thin display module of the present invention can be made by injection molding, and a display hole is set in the middle, in which the light guide plate can be embedded, saving space.

[0021] (4) The special-shaped ultra-thin display module of the present invention further provides a foam layer between the bracket and the diaphragm. The foam layer and the extremely thin diaphragm can be squeezed by the bracket, further filling and reducing the gap between the bracket and the cover plate. In addition, it can effectively block the light from the display light source from entering the adjacent display unit, preventing the light source of the unit to be lit from affecting other units.

[0022] (5) The method of improving the touch sensitivity of the special-shaped ultra-thin display module of the present invention uses the raw count value output by the new generation MSC to be associated with only two parameters, Cs (capacitance) and Cref (reference capacitance), with fewer influencing factors, high signal strength and high signal-to-noise ratio.

[0023] (6) The present invention adopts a touch sensor with integrated MSC, which adopts ratiometric sensing, differential mode, and does not require a reference voltage. It uses a capacitor DAC instead of a current DAC to improve noise performance, and can achieve high signal output and a signal-to-noise ratio of more than 10 times. It solves the problem that the thickness of the dielectric layer of each touch button of the present invention is different, and the touch button area and dielectric thickness have large differences, thereby improving the touch sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of a special-shaped ultra-thin display module.

[0025] Figure 2 It is the explosion of the special-shaped ultra-thin display module Figure 1 .

[0026] Figure 3 It is the explosion of the special-shaped ultra-thin display module Figure 2 .

[0027] Figure 4 This is a schematic diagram of a special-shaped ultra-thin display module bracket.

[0028] Figure 5 This is a schematic diagram of the display panel structure Figure 1 .

[0029] Figure 6 This is a schematic diagram of the display panel structure Figure 2 .

[0030] Figure 7 This is a schematic diagram of the display panel structure Figure 3 .

[0031] Figure 8 is a simplified block diagram of the Sigma Delta method. DETAILED DESCRIPTION

[0032] The present invention will be further illustrated below with reference to specific examples. The examples are implemented based on the technical solutions of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0033] like Figure 1-7 As shown, the special-shaped ultra-thin display module of the present invention includes a diaphragm 4, a foam layer 6, a light guide plate 8, a bracket 5 and a circuit board 3 arranged in sequence. The bracket 5 is a special-shaped bracket. The above components are assembled together to form a special-shaped ultra-thin display module with touch, display and control functions, which can be used in various home appliances, such as washing machines, dishwashers, refrigerators, water heaters, etc.

[0034] The present invention provides a bracket 5 between the circuit board 3 and the diaphragm 4. This bracket 5 fills the entire gap between the special-shaped ultra-thin display module and the cover plate 21, ensuring that the special-shaped ultra-thin display module 1 is in close contact with the special-shaped cover plate 21. The bracket 5 allows the touch buttons of different display units of the special-shaped ultra-thin display module 1 to have different distances from the cover plate 21. The system processes the touch signals of different display units individually, using different parameters to improve resolution and obtain appropriate touch signal values.

[0035] The shape of the bracket 5 is adapted to the shape of the cover plate 21. The upper end of the vertical cross section of the bracket 5 is arc-shaped, stepped or any other non-planar shape. The bracket 5 is made of ABS, PC or other materials using the in-mold injection molding process to form an in-mold injection molded part.

[0036] This embodiment uses a curved cover plate as an example. As shown in the accompanying drawings, the cover plate 21 is curved with a protruding center. To improve touch sensitivity and reduce the distance between the ultra-thin display module and the cover plate 21, a bracket 5 is used to fill the gap. Therefore, the bracket 5 is designed to be curved. The thickness of the curved bracket 5 in the center is greater than that on the sides. The thickest part in the center can reach 8-10 mm, while the thinnest parts on the sides can be as low as 3-5 mm.

[0037] To facilitate the display of the light source and the installation of the light guide plate 8, a plurality of through display holes 7 are provided on the bracket 5. The position and number of the display holes 7 correspond to the display units on the circuit board 3. The shape of the display holes 7 can be set as needed and can be rectangular, or the four corners of the rectangle can be chamfered, or other shapes can be set.

[0038] The special-shaped ultra-thin display module 1 also includes a foam layer 6, which is disposed between the diaphragm 4 and the bracket 5. The thickness of the foam layer 6 is set to 1.5-2 mm, which meets the requirements. The foam layer 6 is made of black foam. The foam layer has two functions: first, it effectively blocks the light from the display light source from entering adjacent display units, preventing the light source of the unit to be illuminated from affecting other units; second, the foam layer 6 is relatively soft. When the special-shaped ultra-thin display module 1 is installed, the foam layer 6 and the extremely thin diaphragm 4 can be squeezed by the bracket 5, further filling and reducing the gap between the bracket 5 and the cover plate 21.

[0039] Through display holes 7 are provided on the foam layer 6 . The positions and number of the display holes 7 on the foam layer 6 correspond to the display units on the circuit board 3 and the display holes 7 on the bracket 5 .

[0040] A light guide plate 8 is arranged between the diaphragm 4 and the circuit board 3. The position and number of the light guide plates 8 correspond to the display units on the circuit board 3. In order to save space and reduce the thickness of the entire special-shaped ultra-thin display module 1, the light guide plates 8 are arranged in the display hole 7.

[0041] The thickness of the light guide plate 8 can match that of the bracket 5 to ensure a tight fit between the light guide plate and the curved display surface. Alternatively, it can be a thin sheet of uniform thickness, with the thicker inner wall of the display aperture 7 of the bracket 5 providing a barrier to accommodate the light guide plate 8. Alternatively, the light guide plate 8 can be integral, but not a single piece. The inner light guide plates of each display aperture are connected by very thin connectors. This facilitates integrated installation, allowing for a single, complete installation without requiring separate light guide plates for each display aperture 7.

[0042] Diaphragm 4 can be black and white or colored. Functionally corresponding pattern areas are provided on diaphragm 4, with each pattern area corresponding one-to-one to display holes 7 on foam layer 6 and bracket 5. The present invention preferably utilizes a colored diaphragm, with multiple pattern areas on the colored diaphragm provided with corresponding color patterns, resulting in a more realistic and vivid display effect.

[0043] like Figure 5-7 As shown, the present invention also discloses a display panel, including a cover plate 21 and a housing 22. The cover plate 21 is arranged on the outer surface of the housing 22, and a special-shaped ultra-thin display module 1 is arranged inside the display panel. The cover plate 21 can be made of glass, or can be made of ABS, PC, or other materials using an in-mold injection molding process to form an in-mold injection molded part.

[0044] The special-shaped ultra-thin display module 1 is embedded in the housing 22 and can be snap-fitted into the housing 22 and sealed with glue, which can achieve good waterproof and fixing effects.

[0045] Because the curved bracket of the present invention causes the thickness of the light guide plate to vary at different locations, the thickness of the dielectric layer of each touch button varies, resulting in significant differences in the touch button area and dielectric thickness. Therefore, in order to improve touch sensitivity, the present invention also discloses a method for improving the touch sensitivity of a special-shaped ultra-thin display module, which is implemented by the following components:

[0046] The device consists of a touch button and an MSC sensor circuit module. The touch button utilizes PCB copper foil, which corresponds to the sensor's touch area. The touch foil is connected to the MSC sensor's GPIO (General-Purpose Input / Output) pins via traces and vias. The touch foil is covered with an insulating cover. When a finger touches the sensor surface, the body's conductive properties and large mass form a grounded conductive layer, forming a parallel plate capacitor. The MSC sensor circuit module utilizes a capacitive touch sensor, which detects changes in the body's capacitance to detect the presence of a finger near the sensor, thus implementing capacitive touch sensing.

[0047] The MSC sensor circuit module of the present invention uses the latest generation of touch sensors integrated with MSC (multi sense converter), which the present invention names as MSC sensor. The entire implementation process and logic of the MSC sensor are as follows:

[0048] MSC sensors use self-capacitance sensing technology: Self-capacitance uses a single pin to measure the change in capacitance between the board it's connected to and its surroundings. Specifically, a switched capacitor circuit on the driving pin converts the sensor capacitance into an equivalent current, and then converts the current signal into a digital signal. When a finger is placed on the sensor plate, the system capacitance increases, and the corresponding digital signal increases. This change in the digital signal is then used to detect a finger touch. This technology is typically used for single-touch or slider applications.

[0049] The solution to the technical problem of the present invention using MSC touch sensor is summarized as follows: the capacitance signal is converted into a micro-current signal through a switching circuit, and the current signal is converted into a digital signal (raw data) through analog-to-digital conversion. The raw count value (raw count) output by the new generation MSC is only associated with two parameters, Cs (capacitance) and Cref (reference capacitance). It has few influencing factors, high signal strength, and high signal-to-noise ratio. The raw count value is calculated after IIR filtering and median filtering to obtain a stable touch signal value. In order to resist external interference of the product (water vapor, soap liquid, etc.), the touch signal will be sliding filtered again. The filtering process uses software filtering, which is set in the following way: Figure 8 The software processing part is shown.

[0050] In this embodiment, the specific implementation process of the MSC touch sensor circuit module is as follows:

[0051] Each GPIO is equipped with a switched capacitor circuit (for Figure 8 The capacitance-to-current conversion (CTC) in the sensor is used to convert the sensor capacitance into an equivalent current. An analog multiplexer then selects one of the current signals and sends it to a current-to-digital converter (Sigma Delta). The operating principle of a current-to-digital converter is similar to that of a Delta Sigma ADC. The output count of the current-to-digital converter (called the raw count value) is a digital value proportional to the self-capacitance between each electrode.

[0052] Relationship between raw count value and sensor capacitance:

[0053] Raw count value = GcCs

[0054] Gc is the capacitance value of digital conversion gain;

[0055] Cs is the self-capacitance of the electrode;

[0056] When a finger touches the sensor, the Cs value increases from Cp to Cp + CF, which in turn increases the raw count. Cp is the capacitance when the finger is not touching the sensor, known as parasitic capacitance. Parasitic capacitance is generated by the electric field between the sensor and other conductors in the system. CF is the parallel finger capacitance generated when the finger touches the sensor surface, due to the conductive properties of the human body and the large mass forming a grounded conductive layer. By comparing the raw count value with a predetermined threshold, the sensor is determined to be active (i.e., whether a finger is touching), and the touch status is determined.

[0057] At the same time, in response to interference factors such as external temperature and coverings, the software system will adopt a variety of measures: regular updates of basic raw data, multiple initializations of MSC sensors, and touch signal timeout processing.

[0058] This invention utilizes the latest capacitive touch technology, MSC (multi-sense converter). Key features include ratiometric sensing, differential mode, and the absence of a reference voltage. The use of a capacitive DAC instead of a current DAC improves noise performance, enabling high signal output and a signal-to-noise ratio exceeding 10x. This solves the problem of varying dielectric thicknesses between touch buttons, resulting in significant variations in both touch button area and dielectric thickness, thereby improving touch sensitivity.

[0059] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A special-shaped ultra-thin display module, characterized in that: A bracket (5) is arranged between the circuit board (3) and the diaphragm (4); the shape of the bracket (5) is adapted to the shape of the cover plate (21); the bracket (5) enables the special-shaped ultra-thin display module (1) to be closely attached to the special-shaped cover plate (21); the bracket (5) causes the distances between the touch keys of different display units of the special-shaped ultra-thin display module (1) and the cover plate (21) to differ; in order to cope with the key differences, the touch signals of the different display units are processed separately, and different parameters are used to improve the resolution to obtain a suitable touch signal value; The components for improving the touch sensitivity of the special-shaped ultra-thin display module include touch buttons and MSC sensor circuit modules. The touch buttons are made of PCB copper foil. The PCB copper foil corresponds to the touch area of ​​the sensor. The touch copper foil is connected to the GPIO pin of the MSC sensor through wiring and vias. The touch copper foil is covered with an insulating cover. The self-capacitance of the MSC sensor is used to sense and receive finger touch signals. The capacitance signal is converted into a micro-current signal through a switch circuit. The current signal is converted into a digital signal as the original count value through analog-to-digital conversion, and then the original count value is filtered. The filtering process is as follows: the original count value is filtered by IIR and median filters, and then the stable touch signal value is calculated. To resist external interference of the product, the touch signal will be filtered again by sliding; Each GPIO has a switched capacitor circuit to convert the sensor capacitance into an equivalent current. The analog multiplexer then selects one of the current signals and sends it to the current-to-digital converter. The output count of the current-to-digital converter, called the raw count value, is a digital value proportional to the self-capacitance between each electrode. Relationship between raw count value and sensor capacitance: Raw count value = GcCs Gc is the capacitance value of digital conversion gain; Cs is the self-capacitance of the electrode; When a finger touches the sensor, the Cs value will increase from Cp to Cp + CF, thereby increasing the raw count. Cp is the capacitance when the finger is not touching the sensor, called parasitic capacitance. CF is the parallel finger capacitance generated by the conductive properties of the human body and the large mass forming a grounded conductive layer when the finger touches the sensor surface. By comparing the raw count value with the predetermined threshold, it is determined whether the sensor is in an activated state and whether there is a finger touch.

2. The special-shaped ultra-thin display module according to claim 1, characterized in that: The special-shaped ultra-thin display module (1) further comprises a foam layer (6), wherein the foam layer (6) is arranged between the diaphragm (4) and the bracket (5).

3. The special-shaped ultra-thin display module according to claim 1, characterized in that: The upper end of the vertical cross section of the bracket (5) is arc-shaped or stepped.

4. The special-shaped ultra-thin display module according to claim 1, characterized in that: Through display holes (7) are provided on both the bracket (5) and the diaphragm (4), and the positions and numbers of the display holes (7) of the two correspond to the display units on the circuit board (3).

5. The special-shaped ultra-thin display module according to claim 1, characterized in that: A light guide plate (8) is arranged between the diaphragm (4) and the circuit board (3); the position and number of the light guide plates (8) correspond to the display units on the circuit board (3); and the light guide plates (8) are arranged in the display hole (7).

6. The special-shaped ultra-thin display module according to claim 5, characterized in that: The thickness of the light guide plate (8) matches the thickness of the bracket (5).

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