Display screen flexible circuit board with anti-peeping function

Abstract

The application discloses a display screen flexible circuit board with a privacy protection function, which comprises a transparent flexible base layer, a privacy protection driving electrode layer, an intermediate transparent insulation layer, a proximity sensing electrode layer, a top transparent protection layer and embedded control circuit components, the privacy protection driving electrode layer is arranged on the upper surface of the transparent flexible base layer, the intermediate transparent insulation layer covers the upper surface of the privacy protection driving electrode layer, the proximity sensing electrode layer is arranged above the intermediate transparent insulation layer, the proximity sensing electrode layer comprises at least four independent sensing channels, the four independent sensing channels are respectively a left sensing channel, a right sensing channel, a front sensing channel and an upper sensing channel, and the four independent sensing channels correspond to the left side of the display screen, the right side of the display screen, the front of the display screen and the upper side of the display screen respectively, and the top transparent protection layer is arranged above the proximity sensing electrode layer.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more specifically, to a flexible circuit board for a display screen with privacy protection function. Background Technology

[0002] With the widespread use of devices such as laptops, ATMs, public information terminals, and medical monitors, the demand for privacy protection of displayed content is becoming increasingly urgent, making privacy-protecting displays the mainstream choice. Currently, the core implementation method of privacy-protecting displays is to superimpose a switchable privacy film (dye-liquid crystal dimming film or electronically controlled grating) on ​​the surface of an ordinary display screen. By applying a driving voltage to control the alignment of liquid crystal molecules, the switching between "wide viewing angle (normal mode)" and "narrow viewing angle (privacy mode)" can be achieved.

[0003] Traditional switchable privacy screen protectors are redundant, costly, and complex to assemble. Driving a switchable privacy screen protector requires an independent driver IC, control board, and flexible cable. At the same time, proximity sensing (if applicable) requires an additional infrared sensor or camera module. As a result, the entire display module requires at least 3-4 FPCs, multiple connectors, and cables, which not only increases material costs and assembly steps but also increases the probability of failure, making it unfavorable for mass production. Summary of the Invention

[0004] The technical problem to be solved by the present invention is how to achieve the privacy protection function of the display screen with fewer components, thereby reducing product cost and assembly difficulty.

[0005] The technical problem to be solved by the present invention is achieved through the following technical solution: To address the aforementioned technical problems, this invention provides a flexible circuit board for a display screen with anti-peeping functionality. The board includes a transparent flexible substrate layer, an anti-peeping driving electrode layer, a middle transparent insulating layer, a proximity sensing electrode layer, a top transparent protective layer, and embedded control circuit components. The anti-peeping driving electrode layer is disposed on the upper surface of the transparent flexible substrate layer. The middle transparent insulating layer covers the upper surface of the anti-peeping driving electrode layer. The proximity sensing electrode layer is disposed above the middle transparent insulating layer and includes at least four independent sensing channels, namely a left sensing channel, a right sensing channel, and a right sensing channel. The system comprises four independent sensing channels: a front sensing channel, a front sensing channel, and an upper sensing channel, corresponding to the left, right, front, and top of the display screen, respectively. A top transparent protective layer is positioned above the proximity sensing electrode layer. Embedded control circuit components are located in the component area at the edge of the flexible circuit board. These components include a capacitance detection circuit, a privacy driving circuit, a microcontroller, and a power management module. The capacitance detection circuit is connected to the proximity sensing electrode layer, the privacy driving circuit is connected to the privacy driving electrode layer, and the microcontroller receives signals from the capacitance detection circuit and controls the privacy driving circuit to operate.

[0006] In a preferred embodiment of the flexible circuit board with anti-peeping function provided by the present invention, the material of the transparent flexible substrate layer is PI or PE, and the thickness of the transparent flexible substrate layer is 12μm-25μm.

[0007] In a preferred embodiment of the flexible circuit board with anti-peeping function provided by the present invention, the thickness of the intermediate transparent insulating layer is 2μm-5μm, and the upper surface of the intermediate transparent insulating layer is covered with a grounded transparent ITO shielding layer, the thickness of which is 1μm-2μm.

[0008] As a preferred embodiment of the flexible circuit board with anti-peeping function provided by the present invention, the thickness of the top transparent protective layer is 1μm-2μm, and the material of the top transparent protective layer is a high light transmittance, scratch-resistant and fingerprint-resistant hard coating.

[0009] As a preferred embodiment of the flexible circuit board with anti-peeping function provided by the present invention, the anti-peeping driving circuit adopts an alternating polarity driving waveform, the peak-to-peak driving voltage is 5V-20V, the frequency is 50Hz-500Hz, and the anti-peeping driving circuit has a built-in boost charge pump.

[0010] As a preferred embodiment of the flexible circuit board with anti-peeping function provided by the present invention, the capacitance detection circuit adopts a self-capacitance detection method, the detection frequency is 50kHz-500kHz, and a time-division multiplexing drive design is adopted to sample capacitance during the interval of the output drive waveform of the anti-peeping drive circuit.

[0011] As a preferred embodiment of the flexible circuit board with anti-peeping function provided by the present invention, the microcontroller is preset with a first threshold and a second threshold. When the capacitance change of one of the sensing channels of the left sensing channel, the right sensing channel, or the top sensing channel exceeds the first threshold and the duration is greater than or equal to 100ms, the microcontroller controls the anti-peeping drive circuit to output a drive voltage. When the capacitance change of one of the sensing channels of the left sensing channel, the right sensing channel, or the top sensing channel is lower than the second threshold and the capacitance change of the front sensing channel exceeds the first threshold, the microcontroller controls the anti-peeping drive circuit to stop outputting.

[0012] The present invention has the following beneficial effects: This invention is an ultra-thin transparent multilayer composite flexible circuit board that can be directly attached between the light-emitting surface of the display screen and the switchable privacy film, or integrally laminated with the privacy film without the need for additional fixing structures. The overall thickness is ≤0.2mm, the visible light transmittance is ≥90%, and the haze is ≤2%.

[0013] When the human body, as a conductor, approaches the sensing electrode, it forms a coupling capacitance with the electrode, causing a change in the capacitance value of the sensing electrode. The microcontroller can be pre-set with a first threshold (trigger threshold) and a second threshold (release threshold). When the capacitance change of one of the sensing channels (left, right, or top) exceeds the first threshold and lasts for more than 100ms, it is determined that someone is peeping from the left or right. The microcontroller immediately controls the anti-peeping drive circuit to output a drive voltage, causing the anti-peeping film to switch to a narrow viewing angle (anti-peeping mode). When the capacitance change of one of the sensing channels (left, right, or top) is lower than the second threshold and the capacitance change of the sensing channel directly in front exceeds the first threshold, it is determined that only someone is normally watching from directly in front. The microcontroller controls the anti-peeping drive circuit to stop outputting, and the anti-peeping film switches to a wide viewing angle (normal mode). When all sensing channels in all directions exceed the first threshold, it is determined that multiple people are watching, and the anti-peeping mode remains on, providing comprehensive privacy protection.

[0014] This allows for the implementation of privacy protection on the display screen with fewer components, thereby reducing product costs and assembly difficulty. Attached Figure Description

[0015] To more clearly illustrate the solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a flexible circuit board for a display screen with anti-peeping function provided by the present invention.

[0017] Figure 2 for Figure 1 A schematic diagram of the structure near the sensing electrode layer.

[0018] Explanation of icon numbers: 1. Transparent flexible substrate layer; 2. Privacy-proof driving electrode layer; 3. Middle transparent insulating layer; 4. Proximity sensing electrode layer; 5. Top transparent protective layer; 6. Embedded control circuit components; Left sensor channel 41; right sensor channel 42; front sensor channel 43; top sensor channel 44. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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, they should not be construed as limitations on this invention.

[0021] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. The present invention will be described in detail below with reference to the accompanying drawings and embodiments, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] Please see Figure 1 and Figure 2 This invention provides a flexible circuit board for a display screen with anti-peeping function, comprising a transparent flexible substrate layer 1, an anti-peeping driving electrode layer 2, a middle transparent insulating layer 3, a proximity sensing electrode layer 4, a top transparent protective layer 5, and embedded control circuit components 6. The anti-peeping driving electrode layer 2 is disposed on the upper surface of the transparent flexible substrate layer 1; the middle transparent insulating layer 3 covers the upper surface of the anti-peeping driving electrode layer 2; the proximity sensing electrode layer 4 is disposed above the middle transparent insulating layer 3, and the proximity sensing electrode layer 4 includes at least four independent sensing channels, namely a left sensing channel 41, a right sensing channel 42, etc. The four independent sensing channels 43 (front) and 44 (top) correspond to the left, right, front, and top of the display screen, respectively. The top transparent protective layer 5 is positioned above the proximity sensing electrode layer 4. The embedded control circuit components 6 are located in the component area at the edge of the flexible circuit board. The embedded control circuit components 6 include a capacitance detection circuit, a privacy driving circuit, a microcontroller, and a power management module. The capacitance detection circuit is connected to the proximity sensing electrode layer 4, the privacy driving circuit is connected to the privacy driving electrode layer 2, and the microcontroller receives the signal from the capacitance detection circuit and controls the privacy driving circuit to operate.

[0024] This invention is an ultra-thin transparent multilayer composite flexible circuit board that can be directly attached between the light-emitting surface of a display screen and a switchable privacy film, or integrally laminated with the privacy film without the need for additional fixing structures. The overall thickness is ≤0.2mm, that is, the thickness of the transparent flexible base layer 1, the privacy driving electrode layer 2, the intermediate transparent insulating layer 3, the proximity sensing electrode layer 4, and the top transparent protective layer 5 is ≤0.2mm. The visible light transmittance is ≥90%, and the haze is ≤2%.

[0025] When a human body, acting as a conductor, approaches the sensing electrode, it forms a coupling capacitance with the electrode, causing a change in the capacitance value of the sensing electrode. The microcontroller can be pre-set with a first threshold (trigger threshold) and a second threshold (release threshold). When the capacitance change of one of the sensing channels—left sensing channel 41, right sensing channel 42, or upper sensing channel 44—exceeds the first threshold and lasts for more than or equal to 100ms, it is determined that someone is peeping from the left or right. The microcontroller immediately controls the anti-peeping drive circuit to output a drive voltage, causing the anti-peeping film to switch to a narrow viewing angle (anti-peeping mode). When the capacitance change of one of the sensing channels—left sensing channel 41, right sensing channel 42, or upper sensing channel 44—is lower than the second threshold and the capacitance change of the front sensing channel 43 exceeds the first threshold, it is determined that only someone is normally watching from the front. The microcontroller controls the anti-peeping drive circuit to stop outputting, and the anti-peeping film switches to a wide viewing angle (normal mode). When all sensing channels exceed the first threshold, it is determined that multiple people are watching, and the anti-peeping mode remains active, providing comprehensive privacy protection.

[0026] This allows for the implementation of privacy protection on the display screen with fewer components, thereby reducing product costs and assembly difficulty.

[0027] The privacy-protecting driving electrode layer 2 is a transparent ITO or silver nanowire electrode array with parallel strips or grids as the electrode pattern, and each electrode is led out independently.

[0028] Furthermore, the transparent flexible substrate 1 is made of PI or PE material with high light transmittance and high flexibility. The thickness of the transparent flexible substrate 1 is 12μm-25μm. It has both insulation and flexibility, and can perfectly fit the surface of flat screen, curved screen and foldable screen. It is not easy to break or deform, and does not affect the light transmission of the screen.

[0029] Furthermore, the intermediate transparent insulating layer 3 is made of transparent photoresist or OCA optical adhesive with high light transmittance and low dielectric constant. The thickness of the intermediate transparent insulating layer 3 is 2μm-5μm. The intermediate transparent insulating layer 3 covers the surface of the privacy driving electrode layer 2, which plays an insulating and isolation role, while ensuring light transmittance and avoiding affecting the screen display effect.

[0030] To further enhance anti-interference capabilities, a grounded transparent ITO shielding layer can be covered on the upper surface of the intermediate transparent insulating layer 3. The thickness of the transparent ITO shielding layer is 1μm-2μm, forming a Faraday cage to isolate the electric field interference between the driving electrode and the sensing electrode.

[0031] Furthermore, the thickness of the top transparent protective layer 5 is 1μm-2μm. The material of the top transparent protective layer 5 is a high light transmittance, scratch-resistant and fingerprint-resistant hard coating, which covers the surface of the near sensing electrode layer 4, protecting the electrode from wear and contamination, while improving the surface hardness of the FPC and extending its service life.

[0032] Furthermore, the privacy protection drive circuit adopts an alternating polarity drive waveform, with a peak-to-peak drive voltage of 5V-20V and a frequency of 50Hz-500Hz. The privacy protection drive circuit has a built-in boost charge pump, which can boost the 3.3V or 5V power supply provided by the display screen to the drive voltage required by the privacy film without the need for an additional boost module.

[0033] Furthermore, the capacitance detection circuit adopts a self-capacitance detection method with a detection frequency of 50kHz-500kHz. It uses a time-division multiplexing drive design to sample capacitance during the intervals of the output drive waveform of the privacy protection drive circuit, thereby eliminating electric field interference.

[0034] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A flexible circuit board for a display screen with anti-peeping function, characterized in that, It includes: Transparent flexible substrate; A privacy-protecting drive electrode layer is disposed on the upper surface of the transparent flexible substrate layer; A transparent insulating layer in the middle covers the upper surface of the privacy-protecting drive electrode layer; The proximity sensing electrode layer is disposed above the intermediate transparent insulating layer. The proximity sensing electrode layer includes at least four independent sensing channels, namely a left sensing channel, a right sensing channel, a front sensing channel, and an upper sensing channel. The four independent sensing channels correspond to the left side, the right side, the front of the display screen, and the top of the display screen, respectively. A top transparent protective layer is disposed above the proximity sensing electrode layer; An embedded control circuit component is disposed in the component area at the edge of a flexible circuit board. The embedded control circuit component includes a capacitance detection circuit, a privacy protection drive circuit, a microcontroller, and a power management module. The capacitance detection circuit is connected to the proximity sensing electrode layer, the privacy protection drive circuit is connected to the privacy protection drive electrode layer, and the microcontroller receives the signal from the capacitance detection circuit and controls the privacy protection drive circuit to work.

2. The flexible circuit board for a display screen with anti-peeping function according to claim 1, characterized in that, The transparent flexible substrate is made of PI or PE material, and the thickness of the transparent flexible substrate is 12μm-25μm.

3. The flexible circuit board for a display screen with anti-peeping function according to claim 1, characterized in that, The thickness of the intermediate transparent insulating layer is 2μm-5μm, and the upper surface of the intermediate transparent insulating layer is covered with a grounded transparent ITO shielding layer, the thickness of which is 1μm-2μm.

4. The flexible circuit board for a display screen with anti-peeping function according to claim 1, characterized in that, The thickness of the top transparent protective layer is 1μm-2μm, and the material of the top transparent protective layer is a high-transmittance, scratch-resistant, and fingerprint-resistant hard coating.

5. The flexible circuit board for a display screen with anti-peeping function according to claim 1, characterized in that, The privacy protection drive circuit uses an alternating polarity drive waveform, with a peak-to-peak drive voltage of 5V-20V and a frequency of 50Hz-500Hz. The privacy protection drive circuit has a built-in boost charge pump.

6. The flexible circuit board for a display screen with anti-peeping function according to claim 1, characterized in that, The capacitance detection circuit adopts a self-capacitance detection method with a detection frequency of 50kHz-500kHz. It uses a time-division multiplexing drive design and performs capacitance sampling during the intervals of the output drive waveform of the privacy protection drive circuit.

7. The flexible circuit board for a display screen with anti-peeping function according to claim 1, characterized in that, The microcontroller is preset with a first threshold and a second threshold. When the capacitance change of one of the sensing channels (left, right, or top) exceeds the first threshold and lasts for more than or equal to 100ms, the microcontroller controls the anti-peeping drive circuit to output a drive voltage. When the capacitance change of one of the sensing channels (left, right, or top) is lower than the second threshold and the capacitance change of the front sensing channel exceeds the first threshold, the microcontroller controls the anti-peeping drive circuit to stop outputting.

Images