Waterproof backlight key core structure for keyboard and manufacturing method thereof

Abstract

The present application relates to the technical field of integrated light source elements on printed circuit boards, and proposes a waterproof backlight key core structure for a keyboard and a manufacturing method thereof. The structure comprises a flexible circuit board, a plurality of light-emitting diodes arranged on the flexible circuit board, a flexible light guide layer covering the surface of the flexible circuit board, a protective layer covering the light guide layer, and a key module mounted on the flexible circuit board. The flexible light guide layer covers the light-emitting diodes and has good light transmission and waterproof properties. Through the above structure, effective sealing and light guiding of the light-emitting diodes are achieved, and the reliability and light emission uniformity of the keyboard in a humid environment are improved. The present application also proposes a corresponding manufacturing method, which comprises flexible circuit board preparation, light-emitting diode installation, light guide layer molding, protective layer processing, and key module assembly, and is suitable for keyboard modules of portable electronic devices such as notebook computers.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of integrating light source elements on a printed circuit board, and in particular to a waterproof backlight key core structure for a keyboard and a manufacturing method thereof. BACKGROUND

[0002] With the popularity of notebook computers and portable electronic devices, keyboards are gradually developing towards thinness, backlighting and high reliability. The existing backlight keyboard usually sets light-emitting diodes on the circuit board, and cooperates with a light guide plate or a diffusion film to guide light to the key unit area to realize key cap character light transmission. However, in long-term use or humid environment, the existing technology still has the following problems:

[0003] Firstly, the backlight module of the traditional keyboard is usually independently set, that is, the light-emitting diodes are usually installed in a bare form or fixed by local packaging, which has poor sealing performance and cannot effectively prevent external water or liquid from entering, thereby causing the light-emitting diodes and their solder joints to be damp or damaged, reducing the reliability, and even directly scrapped and unable to use. Secondly, in order to cooperate with the use of the backlight module, the existing light guide structure is also usually an independent component, which needs to be additionally assembled with the circuit board and the light-emitting diode, or a reflector is set according to the situation, so that the process is more complex, and the sealing performance is insufficient because it is an independent component, and water or liquid may still enter the circuit area through the gap. Furthermore, such a separate design not only increases the thickness of the keyboard, but also easily causes uneven light distribution, light leakage and energy loss. Secondly, the existing light guide structure is usually made of ordinary optical materials, which has a certain light transmission, but is easy to scratch or crack due to repeated pressing or scratching in the long-term use process, thereby causing the optical performance and waterproof performance to decrease, and it is difficult to maintain long-term stability. In addition, the existing keyboard usually relies on mechanical switches or capacitive switches to realize input function, and the input confirmation completely relies on visual or sound prompt, lacking tactile feedback, and the input experience of the user on the thin keyboard is usually not as good as that of the traditional mechanical keyboard. If tactile feedback is to be increased, a vibration unit element usually needs to be additionally installed in the key module or the shell, which not only increases the structural complexity, but also easily damages the overall sealing performance, thereby affecting the waterproof performance.

[0004] Therefore, how to effectively combine waterproof sealing, backlight function and tactile feedback while maintaining the thinness of the keyboard, and at the same time improve the long-term waterproof performance, reliability and user experience of the keyboard, has become a technical problem to be solved in the field. SUMMARY

[0005] The application aims to provide a waterproof backlight key core structure for a keyboard and a manufacturing method thereof, so as to solve the problems of moisture and water entering the light-emitting diode, poor sealing of the backlight module, insufficient durability of the light guide structure, and lack of tactile feedback of the key in the prior art, thereby improving the reliability and user experience of the keyboard in a complex use environment.

[0006] To achieve the above-mentioned purpose, the application provides the following technical scheme:

[0007] A waterproof backlight key core structure for a keyboard comprises a flexible circuit board, the flexible circuit board comprising a first circuit layer, a second circuit layer, and an isolation layer arranged between the two, a plurality of capacitive key switches being arranged in the isolation layer, and at least one vibration unit being integrated in the flexible circuit board, the vibration unit being arranged opposite to the corresponding capacitive key switch; a plurality of light-emitting diodes being arranged on the first circuit layer and arranged in a matrix manner in the gap region of the plurality of capacitive key switches; a flexible light guide layer being arranged on the surface of the first circuit layer and covering the light-emitting diodes, for guiding the light of the light-emitting diodes to the corresponding key unit region, and the flexible light guide layer being made of a polymer material with self-repairing capability, so as to automatically recover when damaged due to pressing or slight scratches, thereby maintaining the light transmission and waterproof properties; a protective layer being arranged on the surface of the flexible light guide layer and having a plurality of openings to avoid the corresponding positions of the capacitive key switches; and a key module comprising a plurality of key units and a key frame, the key module being fixed on the flexible circuit board by the key frame, so that each key unit is arranged opposite to the corresponding capacitive key switch.

[0008] Through the above-mentioned structure design, the light-emitting diodes can realize optical guidance and sealing protection under the overall covering of the flexible light guide layer, and the protective layer further forms a shielding and light-shielding effect, thereby realizing a backlight keyboard key core with uniform backlight and reliable waterproofness.

[0009] (II) Manufacturing method scheme

[0010] The application further provides a manufacturing method of a waterproof backlight key core structure for a keyboard, comprising the following steps: providing a flexible circuit board, forming a plurality of capacitive key switches in the isolation layer, and embedding a vibration unit in the flexible circuit board; arranging a plurality of light-emitting diodes in a matrix manner on the first circuit layer; forming a flexible light guide layer with self-repairing capability on the surface of the first circuit layer to cover the light-emitting diodes; forming a protective layer on the surface of the flexible light guide layer and processing a plurality of openings on the protective layer to avoid the corresponding positions of the capacitive key switches; assembling a key module, and fixing a plurality of key units by a key frame to correspond to the capacitive key switches.

[0011] (III) Beneficial effects

[0012] Compared with the prior art, the present application has the following remarkable advantages:

[0013] 1. Double waterproof sealing: the flexible light guide layer entirely covers the light emitting diode and its welding position, combined with the coverage of the protective layer, forming a multi-layer barrier to avoid the light emitting diode from being damp and water, significantly improving the overall sealing and reliability.

[0014] 2. Self-repairing ability: the flexible light guide layer uses self-repairing polymer material, even if there is a slight damage due to knocking or scratching during long-term use, it can automatically restore its structure and optical performance, prolonging the service life of the keyboard.

[0015] 3. Enhanced tactile feedback: by directly integrating the vibration unit into the soft circuit board, the input trigger and tactile feedback are integrated into one design, maintaining the overall waterproofness while providing users with the real feel of a mechanical keyboard.

[0016] 4. Structure simplification and thickness reduction: by combining the flexible light guide layer with the sealing function, the assembly of additional independent parts is reduced, the overall thickness is reduced, and it is suitable for thin and light notebook keyboards.

[0017] 5. Improved light efficiency: the protective layer can use non-transparent material and set a reflective coating on its surface, so that the divergent light is reflected twice, improving the light energy utilization rate and light brightness.

[0018] In summary, by introducing the synergistic effect of the flexible light guide layer and the protective layer in the keyboard key core, the present application realizes the integrated design of waterproof sealing, optical guidance and structural optimization, significantly improves the use reliability and backlight display effect of the keyboard in a humid environment, and has good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0020] Among them:

[0021] Figure 1 is the sectional view of the waterproof backlight key core structure provided by the technical solution embodiment of the present application;

[0022] Figure 2 is the partial sectional view of the waterproof backlight key core structure provided by the technical solution embodiment of the present application;

[0023] Figure 3 is Figure 1A top view of a light emitting diode arranged in a matrix manner in a capacitive key switch gap region;

[0024] Figure 4 A flow chart of a manufacturing method of a waterproof backlight key core structure provided by the technical solution embodiment;

[0025] Figure 5 A sectional view of a flexible circuit board provided by the technical solution embodiment;

[0026] Figure 6 A sectional view of a first circuit layer of a waterproof backlight key core structure; Figure 5 A sectional view of a light emitting diode arranged on the first circuit layer;

[0027] Figure 7 A sectional view of a flexible light guide layer formed on the first circuit layer of the waterproof backlight key core structure; Figure 6 A sectional view of a protective layer formed on the flexible light guide layer of the waterproof backlight key core structure;

[0028] Figure 8 A sectional view of a flexible circuit board on which the protective layer is formed; Figure 7 A sectional view of a key module formed on the flexible circuit board on which the protective layer is formed;

[0029] Figure 9 A sectional view of a key module formed on the flexible circuit board on which the protective layer is formed; Figure 8

[0030] Main component symbol explanation

[0031] DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0033] Please refer to Figure 1 The waterproof backlight key core structure 100 provided by the technical solution embodiment for a keyboard mainly includes a flexible circuit board 110, a plurality of light emitting diodes 120, a flexible light guide layer 130, a protective layer 140, and a key module 150.

[0034] Please further refer to Figure 2 ​, which is a partial cross-sectional view of the waterproof backlight key core structure 100, to more clearly present the combination and correlation of the main components. Among them, the flexible circuit board 110 includes a first circuit layer 111, a second circuit layer 112, and an isolation layer 113 disposed between the first circuit layer 111 and the second circuit layer 112, and a plurality of capacitive key switches 114 are provided in the isolation layer 113. In this embodiment, the isolation layer 113 can use a polyimide film, and its thickness can range from 0.05 mm to 0.5 mm to ensure electrical isolation and flexibility. Each capacitive key switch 114 can be composed of a corresponding capacitive sensing unit, that is, the capacitive sensing unit includes a sensing electrode 111a formed on the first circuit layer 111 and a corresponding counter electrode 112a formed on the second circuit layer 112, which are isolated from each other by the isolation layer 113 to form a capacitive structure. Specifically, when the user touches or presses the key module 150, the capacitive key switch 114 located below will be pressed, causing the thickness or position of the isolation layer 113 to change, thereby causing the capacitance between the sensing electrode and the counter electrode to change, and the control circuit of the flexible circuit board 110 can detect the above-mentioned capacitance change in real time and convert it into a corresponding input signal, realizing the triggering of the capacitive key. The capacitive key switch 114 used in this embodiment mainly has the following advantages: (1) simplified structure: no metal spring or physical contact, reducing the number of independent components; (2) excellent sealing: the capacitive sensing unit is completely embedded between the flexible circuit board 110, completely sealing the electrical components, suitable for use in humid environments; (3) thin and light: the overall thickness is smaller, meeting the needs of thin keyboards for portable devices such as laptops. The flexible circuit board 110 is provided with at least one vibration unit 115, which is arranged opposite to the corresponding capacitive key switch 114. Specifically, the vibration unit 115 can use a micro vibration unit motor or a piezoelectric element, for example: (1) Micro Linear Resonant Actuator (LRA): by driving the coil to produce reciprocating vibration in the magnetic field, the structure is compact, the response speed is fast, and it can provide a short and clear tactile feedback when the user presses the key; (2) Eccentric Rotating Mass (ERM): by driving the rotor with eccentric mass to rotate to produce a vibration unit, suitable for low-frequency vibration unit feedback, with lower cost but larger thickness; (3) Piezoelectric Element: composed of a piezoelectric ceramic sheet or film, which produces deformation or micro-vibration when a driving voltage is applied, and can be integrated in an extremely thin structure, suitable for thin and light keyboards.In this embodiment, the vibration unit 115 is a piezoelectric element with a thickness of less than 0.5 mm, which can be directly embedded in the flexible circuit board 110, for example, it can be disposed in the second circuit layer 112. Through electrical correspondence with the capacitive key switch 114, when the user presses a keyboard key, the control circuit can simultaneously identify the change in capacitance and drive the vibration unit 115 to operate, thereby achieving instant tactile feedback without compromising the overall sealing. Through the above design, the vibration unit 115 and the capacitive key switch 114 work together to provide the user with not only visual backlighting cues but also tactile feedback each time they input, effectively improving the input confirmation feel and user experience of the thin keyboard.

[0035] The light-emitting diode 120 is disposed on the first circuit layer 111. The light-emitting diode 120 can be in flip-chip or chip-scale package (CSP) form to reduce the overall mounting size and improve heat dissipation performance. More specifically, as... Figure 3 As shown, the light-emitting diodes (LEDs) 120 are arranged in a matrix within the gaps of the capacitive key switches 114. Because the LEDs 120 and the capacitive key switches 114 are staggered, the light emitted by the LEDs 120 is mainly distributed in the gaps between the keys, preventing direct interference with the light when the user touches or presses the key module 150. This arrangement allows each LED 120 to evenly direct light into two or more adjacent key areas, achieving shared and balanced backlighting. Furthermore, the spacing of the LEDs 120 can be optimized according to the keyboard key spacing design, with a preferred center-to-center spacing of 8 mm to 20 mm to ensure uniform light coverage and brightness. In small-sized laptop keyboards, the LED density can be higher to avoid localized dark areas; while in full-size keyboards, a larger spacing can be used to reduce the number of components and lower power consumption. Furthermore, the light-emitting diodes 120 can be fixed to the conductive pads on the first circuit layer 111 using surface mount technology and electrically connected to the driving circuit of the flexible circuit board 110, thereby enabling single-diode or zone control. Preferably, backlight brightness adjustment can be achieved by combining PWM (pulse width modulation) dimming, or RGB (red, green, and blue) light effect switching can be achieved by multi-channel driving. Through the above matrix arrangement, the light-emitting diodes 120 can not only improve the overall lighting uniformity and display effect of the keyboard, but also significantly reduce light spots and light leakage problems after being combined with the optical diffusion effect of the flexible light guide layer 130, thereby ensuring that users can obtain a consistent visual experience from different angles.

[0036] The flexible light guide layer 130 covers the surface of the first circuit layer 111, and the flexible light guide layer 130 covers the light-emitting diode 120. The flexible light guide layer 130 is made of a self-repairing polymer material, which not only plays an optical light guide and diffusion role, but also protects the light-emitting diode 120 to form a waterproof sealing barrier, thereby preventing external liquid from eroding the light-emitting diode 120 and the internal circuit. In material selection, the flexible light guide layer 130 can use at least one of a self-repairing transparent silicone, a self-repairing polyurethane, and a self-repairing siloxane modified resin. The self-repairing polymer material has a dynamic covalent bond or a supramolecular structure, which can realize self-healing at room temperature or under slight heating conditions. When the flexible light guide layer 130 has small cracks or depressions due to long-term pressing, rubbing, or slight scratches, the dynamic chemical bond or reversible crosslinking network inside the material can self-reconstruct, so that the damaged area gradually returns to its original state, thereby maintaining the light transmission and waterproof performance of the flexible light guide layer 130. In an embodiment, when a self-repairing transparent silicone is used, it has excellent high-temperature resistance and humidity resistance, and can maintain stability under long-term use of the keyboard or in a high-humidity environment. When a self-repairing polyurethane (PU) is used, it can provide better mechanical flexibility and wear resistance, which is suitable for the repeated pressing requirements of thin keyboard structures. When a self-repairing siloxane modified resin is used, it can further improve the optical transmittance and anti-yellowing performance, and prolong the service life of the keyboard backlight. In a variant, the material of the flexible light guide layer 130 can also be a combination of the above-mentioned materials to balance the optical performance and structural reliability. Through the above design, the flexible light guide layer 130 not only provides uniform backlight effect and effective waterproof protection, but also can self-repair surface damage during use, prolonging the stable use period of the overall keyboard module. Further, the flexible light guide layer 130 can be dispersed and filled with at least one of titanium dioxide, aluminum oxide, quartz powder, or glass microbeads. When titanium dioxide or aluminum oxide is filled, it can significantly enhance the light scattering and reflection effect, making the light evenly diffuse in the light guide layer and reducing light spots. When quartz powder is filled, it can improve the mechanical strength and wear resistance of the light guide layer as a whole, avoiding scratches or indentations caused by long-term use. When glass microbeads are filled, they can enhance the multi-angle refraction of light through micron-sized spherical particles, further improving light uniformity. Through the above design, the flexible light guide layer 130, while covering the light-emitting diode 120, can have high light transmission, waterproofness, and diffusivity, so that the light can form a uniform backlight effect under the key module 150, effectively improving the reliability and service life of the entire machine in a humid environment.

[0037] The protective layer 140 is coated on the surface of the flexible light guide layer 130 to further form optical and mechanical protection. That is, the protective layer 140 can provide the function of blocking light and also the function of protecting the flexible light guide layer 130. Moreover, the protective layer 140 has a plurality of openings 141 so that the protective layer 140 avoids the corresponding positions of the capacitive key switch 114. In other words, each opening 141 corresponds to the position of the capacitive key switch 114, so as to ensure that the key module 150 can maintain an effective input triggering relationship with the corresponding capacitive key switch 114 when the protective layer 140 is covered. Specifically, the openings 141 can be formed by laser cutting or punching process to ensure accurate position and smooth edge. In the embodiment, the protective layer 140 adopts a lightproof material to block the light in the flexible light guide layer 130 from leaking to a non-target area, and limit the light to pass through the openings 141 only via the blocking of the protective layer 140. In other words, the openings 141 are the target area of the light path, and the area outside the openings 141 is the non-target area. Preferably, the protective layer 140 can be made of black polyimide, polycarbonate or lightproof polymer material. Such materials not only have good optical shielding property, but also have heat resistance and mechanical strength, and can maintain stable performance under high-frequency pressing and long-term use conditions. In order to further improve the optical utilization rate, the surface of the protective layer 140 can be coated with a light-reflecting coating. Specifically, the light-reflecting coating can be an aluminum plating layer, a silver plating layer or a high-reflective white paint layer. The light-reflecting coating can reflect part of the light escaping from the flexible light guide layer 130 back to the target area, thereby improving the light energy utilization rate and brightness uniformity. In addition, the light-reflecting coating can also effectively suppress the scattering of light to non-target directions and reduce the light leakage phenomenon. The light-reflecting coating is coated on the surface of the protective layer 140 to reflect the light escaping from the flexible light guide layer 130, and does not require the protective layer 140 itself to be lightproof. Through the above design, the protective layer 140 not only plays the role of optical shielding and reflection enhancement, but also forms additional mechanical protection and waterproof sealing on the surface of the flexible light guide layer 130, thereby further improving the reliability and optical performance of the waterproof backlight key core structure 100.

[0038] The key module 150 comprises a plurality of key units 151 and at least one key frame 152. In an embodiment, the key unit 151 can adopt an integrated structure of a key cap 151a and a support component 151b, or can also adopt a split structure according to design needs. Preferably, the key cap 151a can be made of a light-transmitting material (such as polycarbonate PC or polymethyl methacrylate PMMA), and characters are printed or laser-etched on the surface to ensure clear character transmission under backlight. The support component 151b can be a guide column sliding mechanism for ensuring the stable stroke of the key in the vertical direction. The key frame 152 is used for uniformly positioning and supporting the plurality of key units 151, and the material thereof can be high-strength engineering plastic or metal sheet. The key frame 152 is fixed on the flexible circuit board 110 by means of buckling, screwing or hot melting welding, etc. Preferably, the bottom of the key frame 152 is provided with a plurality of mounting holes or protruding structures, which are embedded with the positioning holes or flanges on the flexible circuit board 110, thereby realizing high-precision fixing. In the assembly process, the key module 150 is integrally mounted on the flexible circuit board 110 through the key frame 152, so that each key unit 151 is oppositely arranged with the corresponding capacitive key switch 114. When a user presses a key unit 151, the corresponding capacitive key switch 114 is triggered, and the control circuit can recognize the input action. At the same time, the control circuit can simultaneously recognize the change of the capacitance value and drive the vibration unit 115 to work, so as to realize instant tactile feedback. Since the light-emitting diodes 120 are distributed in the gap region between adjacent keys, and the light is uniformly guided to the light-transmitting region of the key cap 151a through the flexible light guide layer 130, the key module 150 can realize the synchronization function of input and backlight display. Further, the key module 150 can also be designed as a detachable structure, so as to quickly replace individual key units 151 during keyboard maintenance or replacement, without the need to integrally disassemble the flexible circuit board 110. This design not only improves the maintenance convenience of the keyboard, but also reduces the manufacturing and after-sales costs. In this embodiment, in order to simultaneously meet the lightweight design and waterproof sealing needs of the keyboard, the capacitive key switch 114 is adopted, and all electronic components (including the vibration unit 115 and the related control circuit) that need to be electrically connected are integrated in the flexible circuit board 110, and no electronic components are arranged in the key module 150.In the present embodiment, the so-called "integration" refers to embedding electronic components inside the flexible circuit board 110 or manufacturing them integrally, for example, in the manufacturing process of embedding the vibration unit 115, a mounting groove (e.g. laser ablation or mechanical drilling) can be pre-formed in the second circuit layer 112, and then the vibration unit 115 is embedded in the mounting groove in a surface mount manner, and an electrical connection relationship is established through a via hole or conductive glue. After encapsulation, the overall structure of the flexible circuit board 110 remains flat and does not affect the electrical performance and sealing performance of the capacitive key switch 114 located in the isolation layer 113. In this way, the circuit part and the key module 150 are completely isolated, so that the key module 150 only serves as a mechanical input and optical transmission unit and does not involve electrical functions. At the same time, the flexible light guide layer 130 covers the surface of the flexible circuit board 110 and covers the light-emitting diode 120, forming a first layer of sealing barrier; the protective layer 140 further covers the flexible light guide layer 130, forming a second layer of protective barrier. The double structure of the flexible light guide layer 130 and the protective layer 140 cooperates with each other, which not only ensures the uniformity of the optical output of the light-emitting diode 120, but also effectively prevents external liquid or dust from penetrating into the internal circuit area, thereby realizing high-level waterproof and dustproof performance of the whole machine. Through the integrated design, the key module 150 does not contain electronic components, so that in daily use, even if oil stains, sweat stains or dust are attached to the surface, they can be directly cleaned by washing or wiping without affecting the reliability of the internal circuit. In addition, when the keycap 151a is worn, the characters are missing, or the support structure is damaged, the user can directly replace the corresponding keycap 151a without touching or disassembling the flexible circuit board 110, thereby greatly simplifying the maintenance process and reducing the maintenance cost.

[0039] Please refer to Figure 4 which is a flow chart of the manufacturing method of the waterproof backlight key core structure 100 for the keyboard provided by the present technical solution embodiment, mainly including the following steps:

[0040] First step S1, please refer to Figure 5The soft circuit board 110 is provided, which comprises a first circuit layer 111, a second circuit layer 112, and an isolation layer 113 arranged between the first circuit layer 111 and the second circuit layer 112, and a plurality of capacitive key switches 114 are arranged in the isolation layer 113. Preferably, the first circuit layer 111 and the second circuit layer 112 can be copper foil layers with specific patterns formed by etching on a copper-clad substrate, which are used as carriers and paths for electrical connection and are supported by a flexible substrate to ensure the overall bendability and stable conductivity. The isolation layer 113 can be made of polyimide film, epoxy resin or other high polymer insulating materials, and the thickness thereof is preferably in the range of 0.05 mm to 0.5 mm to ensure that the overall flexibility is not affected while maintaining electrical insulation. A plurality of capacitive key switches 114 are arranged in the isolation layer 113. In an embodiment, the capacitive key switch 114 is of a capacitive structure, which comprises a sensing electrode arranged on the first circuit layer 111 and a counter electrode arranged on the second circuit layer 112, and the two are isolated from each other by the isolation layer 113 to form a capacitor. Therefore, the soft circuit board 110 not only can carry light-emitting diodes 120, chips and other components, but also can integrate the key input function at the same time, thereby realizing the integration of the circuit and the optical module and providing a reliable substrate for the subsequent stacking of the flexible light guide layer 130 and the protective layer 140. At least one vibration unit 115 is arranged in the soft circuit board 110, and the vibration unit 115 is arranged opposite to the corresponding capacitive key switch 114. Specifically, the vibration unit 115 can be a micro vibration unit motor or a piezoelectric element. In this embodiment, the vibration unit 115 can be a piezoelectric element with a thickness of less than 0.5 mm, which can be directly embedded in the soft circuit board 110, such as being arranged on the second circuit layer 112.

[0041] In the second step S2, please refer to Figure 6, a plurality of light emitting diodes 120 are arranged on the first circuit layer 111 and arranged in a matrix manner in the gap region of the plurality of capacitive key switch 114. The light emitting diodes 120 can adopt a flip chip or chip scale package (CSP) structure to reduce the overall package thickness, meet the design requirements of thin keyboard, and improve heat dissipation and electrical reliability. Specifically, the light emitting diodes 120 are arranged in a staggered manner with the capacitive key switch 114, thereby avoiding light passing through the key input position. Therefore, each light emitting diode 120 can uniformly cover the adjacent key area, forming a uniform backlight effect. Preferably, the arrangement pitch of the light emitting diodes 120 can be designed according to the keyboard key distance, and the center distance range is 8 mm~20 mm. In a small notebook keyboard, a smaller pitch can be used to avoid dark areas; in a full-size keyboard, the pitch can be appropriately increased to reduce the number of devices and reduce power consumption. In the embodiment, the light emitting diodes 120 are fixed on the pad position of the first circuit layer 111 through tin paste printing, and are electrically connected with the driving circuit of the flexible circuit board 110. Through the above design, the light emitting diodes 120 can not only ensure the uniformity of optical illumination, but also further reduce the problem of light spot and light leakage after combining the diffusion effect of the flexible light guide layer 130, thereby improving the overall quality of the keyboard backlight display.

[0042] The third step S3, please refer to Figure 7On the surface of the first circuit layer 111, a flexible light guide layer 130 is formed to cover the light emitting diode 120. In detail, the flexible light guide layer 130 is made of a self-repairing polymer material, which not only serves as a light guide and diffusion layer, but also forms a sealing barrier to protect the light emitting diode 120 and the internal circuit from water. In terms of manufacturing process, the flexible light guide layer 130 can be formed by injection molding. Through mold forming, the flexible light guide layer 130 can be tightly attached to the flexible circuit board 110, and can completely cover the light emitting diode 120 to avoid air gap, thereby improving optical coupling efficiency and enhancing sealing performance. In this embodiment, the flexible light guide layer 130 can be selected from at least one of self-repairing transparent silicone, self-repairing polyurethane, and self-repairing siloxane modified resin. When the flexible light guide layer 130 is slightly damaged due to long-term pressing, rubbing, or minor scratches, the dynamic chemical bonds or reversible cross-linking network inside the material can self-repair, gradually restoring the damaged area to its original state, thereby maintaining the light transmission and waterproof performance of the flexible light guide layer 130. Further, the flexible light guide layer 130 can be filled with at least one of titanium dioxide, aluminum oxide, quartz powder, and glass microbeads. Through the above design, the flexible light guide layer 130 not only realizes light guiding and diffusion, but also has the functions of sealing, waterproofing, and structural protection, so that the light emitting diode 120 can work stably in a humid environment, and the uniformity and brightness of the keyboard backlight are guaranteed.

[0043] In the fourth step S4, please refer to Figure 8A protective layer 140 is formed on the surface of the flexible light guide layer 130, and the protective layer 140 has a plurality of openings 141, so that the protective layer 140 avoids the corresponding positions of the capacitive key switch 114. The protective layer 140 covers the surface of the flexible light guide layer 130 as a whole, and is used to provide optical shielding and mechanical protection. The openings 141 ensure the normal cooperation between the key module 150 and the capacitive key switch 114. In this embodiment, the openings 141 can be formed by laser cutting or punching. Laser cutting can achieve high-precision edge processing, ensuring that the positions and sizes of the openings 141 completely correspond to the capacitive key switch 114, and is suitable for small-sized or high-density arranged keyboard structures. Punching is suitable for mass production, has low cost, and has smooth cutting edges. In addition, the protective layer 140 can be formed by pressing or printing. The pressing process can tightly combine the protective layer 140 and the flexible light guide layer 130, enhance the overall sealing performance, and have better flexibility. The printing process can facilitate the patterning of the protective layer 140, and is more suitable for local protection of complex circuit layout. The protective layer 140 is made of light-proof material to avoid light leakage and interference with adjacent keys. Preferably, the protective layer 140 can be black polyimide, polycarbonate or other high molecular materials, which not only have good optical shielding property, but also have heat resistance and mechanical strength, and can maintain stable performance under long-term and frequent pressing. Further, the surface of the protective layer 140 can be covered with a reflective coating, such as an aluminum plating layer, a silver plating layer or a high-reflective white paint layer. The reflective coating can reflect the light escaping from the flexible light guide layer 130 to the area needing light transmission, thereby improving the light efficiency and backlight uniformity, and reducing the light leakage. Through the above design, the protective layer 140 not only forms a sealed cooperation with the flexible light guide layer 130 in structure, and realizes the secondary protection of the light-emitting diode 120 and the internal circuit, but also shields and reflects light in optics, so that the backlight effect is brighter and more uniform, and the reliability and use experience of the keyboard are significantly improved.

[0044] In the fifth step S5, please refer to Figure 9, the key module 150 is installed, the key module 150 includes a plurality of key units 151 and at least one key frame 152, that is, the key module 150 is close to the flexible circuit board 110, so that the key module 150 is fixed on the flexible circuit board 110 through the key frame 152, and each key unit 151 is arranged opposite to the corresponding capacitive key switch 114. The key frame 152 is used for uniformly positioning and supporting the plurality of key units 151, and the material of the key frame 152 can be a metal sheet or an engineering plastic. The key frame 152 can be installed on the flexible circuit board 110 in a buckle, screw or hot melt fixing mode. In order to further improve the assembly precision, the bottom of the key frame 152 can be provided with positioning bumps or mounting holes, which are matched with positioning grooves or flanges on the flexible circuit board 110, so that the key unit 151 is aligned with the corresponding capacitive key switch 114. After installation is completed, each key unit 151 directly faces the capacitive key switch 114. When a user presses the key unit 151, the support structure drives the keycap 151a to move downward and triggers the capacitive key switch 114 in the isolation layer 113, and the circuit can detect and identify the input signal. At the same time, since the light-emitting diodes 120 are distributed in the gap region of the capacitive key switch 114, and combined with the optical effect of the flexible light guide layer 130 and the protective layer 140, the key character region can obtain uniform backlight effect, thereby realizing the synchronous function of input and display. In a variant, the key module 150 can also be designed as a detachable structure. Specifically, each key unit 151 can be independently assembled and disassembled through a buckle, which facilitates quick replacement or maintenance during use without the need to disassemble the keyboard as a whole. This design not only improves the convenience of use and maintenance, but also reduces production and after-sales costs. Since the key module 150 only serves as a mechanical input and optical transmission unit and does not involve electrical functions, even if oil stains, sweat stains or dust are attached to the surface during daily use, they can be directly cleaned by washing or wiping without affecting the reliability of the internal circuit. In addition, when the keycap 151a is worn, the characters are detached or the support structure is damaged, the user can directly replace the corresponding keycap 151a without touching or disassembling the flexible circuit board 110, thereby greatly simplifying the maintenance process and reducing maintenance costs.

[0045] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the foregoing embodiments of the present application have been described in detail, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A waterproof backlit key core structure for a keyboard, characterized in that, include: A flexible circuit board, comprising a first circuit layer, a second circuit layer, and an isolation layer disposed between the first circuit layer and the second circuit layer, wherein a plurality of capacitive push-button switches are disposed within the isolation layer, and at least one vibration unit is disposed within the flexible circuit board, wherein the vibration unit is disposed opposite to the corresponding capacitive push-button switch; Multiple light-emitting diodes are disposed on the first circuit layer and arranged in a matrix in the gap area of ​​the multiple capacitive push-button switches; A flexible light guide layer is provided, covering the surface of the first circuit layer, and the flexible light guide layer encapsulates the light-emitting diode. The flexible light guide layer is made of a self-healing polymer material. A protective layer covers the surface of the flexible light guide layer, and the protective layer has multiple openings, so that the protective layer avoids the corresponding position of the capacitive push button switch; as well as A button module, comprising multiple button units and at least one button frame, wherein the button module is fixed to the flexible circuit board via the button frame, and each button unit is positioned opposite to its corresponding capacitive push-button switch.

2. The waterproof backlit key core structure for a keyboard as described in claim 1, characterized in that, The flexible light guide layer is made of at least one of self-healing transparent silicone, self-healing polyurethane, and self-healing siloxane-modified resin, so that it can automatically recover after being pressed or scratched.

3. The waterproof backlit key core structure for a keyboard as described in claim 2, characterized in that, The flexible light guide layer is dispersed and filled with at least one of titanium dioxide, aluminum oxide, quartz powder and glass microspheres.

4. The waterproof backlit key core structure for a keyboard as described in claim 1, characterized in that, The protective layer is made of black polyimide, polycarbonate, or opaque polymer material.

5. The waterproof backlit key core structure for a keyboard as described in claim 4, characterized in that, The surface of the protective layer is covered with a reflective coating, which is selected from aluminum plating, silver plating or high-reflectivity white paint.

6. A method for manufacturing a waterproof backlit key core structure for a keyboard, characterized in that, include: A flexible circuit board is provided, the flexible circuit board including a first circuit layer, a second circuit layer and an isolation layer disposed between the first circuit layer and the second circuit layer, the isolation layer is provided with a plurality of capacitive push-button switches, and the flexible circuit board is provided with at least one vibration unit, the vibration unit being disposed opposite to the corresponding capacitive push-button switch; Multiple light-emitting diodes are provided, which are located on the first circuit layer and arranged in a matrix in the gap area of ​​the multiple capacitive push-button switches; A flexible light guide layer is formed on the surface of the first circuit layer, so that the flexible light guide layer covers the light-emitting diode, and the flexible light guide layer is made of a self-healing polymer material; A protective layer is formed on the surface of the flexible light guide layer, and the protective layer has multiple openings, such that the protective layer avoids the corresponding position of the capacitive push-button switch; and The button module is installed, which includes multiple button units and a button frame. The button module is fixed to the flexible circuit board through the button frame, so that each button unit is arranged opposite to the corresponding capacitive push button switch.

7. The method for manufacturing the waterproof backlit key core structure for a keyboard as described in claim 6, characterized in that, The opening in the protective layer is formed by laser cutting or punching.

8. The method for manufacturing the waterproof backlit key core structure for a keyboard as described in claim 6, characterized in that, The flexible light guide layer is formed by injection molding, and its material is selected from at least one of self-healing transparent silicone, self-healing polyurethane and self-healing siloxane modified resin, so that it can automatically recover after being pressed or scratched.

9. The method for manufacturing the waterproof backlit key core structure for a keyboard as described in claim 8, characterized in that, The flexible light guide layer is filled with at least one of titanium dioxide, aluminum oxide, quartz powder and glass microspheres.

10. The method for manufacturing the waterproof backlit key core structure for a keyboard as described in claim 6, characterized in that, The protective layer is formed by lamination or printing processes and is made of black polyimide, polycarbonate or opaque polymer materials.

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