Backlight circuit board, backlight module, backlight key and keyboard

Abstract

The utility model provides a backlight circuit board, a backlight module, a backlight key and a keyboard, the backlight circuit board is used for bearing a keycap, the backlight circuit board comprises a substrate, a switch circuit, a light emitting circuit and a light source; the substrate is provided with a plurality of broken holes and a plurality of connecting pieces, the plurality of broken holes penetrate through the substrate, the plurality of connecting pieces are arranged on the substrate, and the plurality of connecting pieces are used for directly or indirectly connecting the keycaps; the switch circuit is arranged on the substrate, the switch circuit is provided with a switch connecting pad, and the switch connecting pad moves towards the substrate from the key cap to trigger a key signal; the light-emitting circuit is arranged on the substrate and is positioned on the opposite side of the plurality of connecting pieces; the light source is electrically connected with the light-emitting circuit, and the vertical projection of the switch connecting pad and the vertical projection of the light source jointly fall within the surrounding range of the connecting pieces.

Description

Technical Field

[0001] The utility model relates to a backlight circuit board, in particular to a backlight circuit board with a key connector, a switch circuit and a light-emitting circuit, and a backlight module, a backlight key and a keyboard comprising the backlight circuit board. Background Art

[0002] In the prior art, backlit keys and keyboards are typically manufactured by separately manufacturing the key structure that generates the trigger signal and the backlight module that provides the backlight. The key structure and backlight module are then laminated together. However, the key structure and backlight module in the prior art are both multi-layer stacked, making it difficult to reduce the overall thickness of the backlit keys (or keyboards), hindering device thinning. Utility Model Content

[0003] The utility model provides a backlight circuit board, a backlight module, a backlight key and a keyboard to solve the above technical problems.

[0004] In order to achieve the above-mentioned objectives, the present invention proposes a backlight circuit board for carrying keycaps, the backlight circuit board comprising a substrate, a switching circuit, a light-emitting circuit and a light source; the substrate has a plurality of holes and a plurality of connectors, the plurality of holes passing through the substrate, the plurality of connectors are arranged on the substrate, and the plurality of connectors are used to directly or indirectly connect to the keycaps; the switching circuit is arranged on the substrate, the switching circuit has a switch pad, and the switch pad triggers a key signal when the keycap moves toward the substrate; the light-emitting circuit is arranged on the substrate and is located on the opposite side of the plurality of connectors; the light source is electrically connected to the light-emitting circuit, wherein the vertical projections of the switch pad and the light source fall together within the surrounding range of the plurality of connectors.

[0005] As an optional technical solution, the substrate is a non-metallic plate, so that the upper surface and the lower surface of the substrate are insulating surfaces.

[0006] As an optional technical solution, the substrate includes a metal plate and at least one insulating layer, and the at least one insulating layer at least partially covers the upper surface and the lower surface of the metal plate.

[0007] As an optional technical solution, the at least one insulating layer at least covers the hole wall of at least one of the plurality of holes, the side wall of the metal plate and / or the surface of at least one of the plurality of connecting members.

[0008] As an optional technical solution, a vertical projection of the switch pad overlaps with the light source.

[0009] As an optional technical solution, a vertical projection of the switch circuit at least partially overlaps with the light-emitting circuit.

[0010] As an optional technical solution, the backlight circuit board further includes at least one protective layer, wherein the at least one protective layer is disposed on the substrate and covers the switch circuit and / or the light-emitting circuit.

[0011] As an optional technical solution, the substrate has a plurality of ribs to define the plurality of holes, the protective layer has a microstructure or the protective layer has a reflective surface and a microstructure, and the microstructure overlaps with at least one of the plurality of ribs of the substrate.

[0012] As an optional technical solution, the keycap has a light emitting area and a non-light emitting area, the protective layer has a microstructure or the protective layer has a reflective surface and a microstructure, and the microstructure overlaps with the non-light emitting area of ​​the keycap.

[0013] As an optional technical solution, the substrate has a plurality of ribs to define the plurality of holes, and the switch circuit and the light-emitting circuit are respectively disposed on the upper side and the lower side of at least one of the plurality of ribs.

[0014] In addition, the present invention also provides a backlight module, which includes the backlight circuit board and the light guide plate as described above, wherein the light emitted by the light source enters the light guide plate and is transmitted laterally to illuminate the keycap.

[0015] As an optional technical solution, the light guide plate has a light hole, and the light source is accommodated in the light hole.

[0016] As an optional technical solution, the backlight module further includes an adhesive layer, wherein the adhesive layer surrounds the light source and is disposed between the light guide plate and the substrate, and forms an adhesive-free area between the light hole and the adhesive layer.

[0017] As an optional technical solution, the backlight module further includes a reflective layer, wherein the reflective layer is arranged on the opposite side of the light guide plate relative to the substrate.

[0018] As an optional technical solution, the backlight module further includes a light shielding sheet, wherein the light shielding sheet is arranged between the substrate and the light guide sheet, and the light shielding sheet has at least one light-transmitting window corresponding to the keycap.

[0019] As an optional technical solution, the light shielding plate has a light source through-hole, the light guide plate has a light hole corresponding to the light source through-hole, and the light source passes through the light source through-hole and is accommodated in the light hole.

[0020] In addition, the present invention also provides a backlight key, which includes the backlight circuit board and the keycap as described above.

[0021] In addition, the present invention also provides a backlight keyboard, which includes the backlight circuit board and the keycap as described above.

[0022] The present invention provides a backlight circuit board, a backlight module, a backlight key, and a keyboard. The backlight circuit board not only serves as the base plate of the key structure, but also includes a switching circuit and a lighting circuit, thereby serving as both the switch circuit board for the key structure and the light source circuit board for the backlight module. Furthermore, the backlight circuit board of the present invention integrates the key structure's switching circuit and the backlight module's lighting circuit into the key structure's base plate, effectively reducing the overall thickness of the key structure and promoting a thinner design. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] Figure 1 This is a schematic diagram of a stack of backlit keyboards according to an embodiment of the present invention;

[0025] Figure 2 This is a cross-sectional diagram of a backlight key according to an embodiment of the present invention;

[0026] Figure 3 A bottom view schematically shows the arrangement of the lower surface of the backlight circuit board around the light source according to an embodiment of the present invention;

[0027] Figure 4 This is a top view of a backlight circuit board corresponding to a single key according to an embodiment of the present invention;

[0028] Figure 5 This is a bottom view schematic diagram of a backlight circuit board corresponding to a single key according to an embodiment of the present invention;

[0029] Figure 6A A bottom view schematically illustrates the configuration of a backlight circuit board and a lifting mechanism corresponding to multiple buttons according to an embodiment of the present invention;

[0030] Figure 6B for Figure 6A A bottom-up schematic diagram of a backlight circuit board without a lifting mechanism;

[0031] Figure 7 FIG1 is a top view of a backlight circuit board corresponding to multiple buttons according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] To more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. Those skilled in the art should understand that the following detailed description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0033] This utility model mainly involves the integrated application of the bottom plate of the key structure, the switch circuit of the key structure and the luminous circuit of the backlight module, which can reduce the overall thickness of the key and improve the ultimate luminous efficiency and luminous uniformity of the backlight module per unit light output of a single key or even the entire key panel. Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a stack of a backlight keyboard KB according to an embodiment of the present invention. Figure 2 1 is a cross-sectional view of a backlight key 1 according to an embodiment of the present invention. In one embodiment, the backlight keyboard KB of the present invention comprises a plurality of keys KS (such as square keys SK or multiple keys MK) and a backlight module BL, wherein each key KS (such as Figure 2 The backlight key 1) includes a keycap 12, a lifting mechanism 14, a reset member 18 and a backlight circuit board 10; for the backlight keyboard KB, the backlight module BL may include the backlight circuit board 10, a light shielding plate 250, a light guide plate 210 and a reflective layer 220. That is, the backlight circuit board 10 can also serve as the base plate of the key KS, the switch circuit board of the key KS and the light source circuit board of the backlight module BL.

[0034] like Figure 2As shown, the keycap 12 is arranged above the backlight circuit board 10 and has a light-emitting area 122 (for example, one or more translucent characters) and a non-light-emitting area 124. The lifting mechanism 14 is connected between the backlight circuit board 10 and the keycap 12 to support the keycap 12 to move up / down relative to the backlight circuit board 10. The backlight circuit board 10 is arranged below the keycap 12 and has a switch circuit 160, and the switch circuit 160 is preferably located on the upper surface of the backlight circuit board 10. The switch circuit 160 has a switch pad 162 as a switch unit. When the keycap 12 is pressed, the switch pad 162 of the switch circuit 160 will be turned on to trigger the key signal. The reset member 18 is arranged between the keycap 12 and the backlight circuit board 10 to provide a restoring force so that the keycap 12 can move upward relative to the backlight circuit board 10 and return to its position before being pressed after being pressed. In this embodiment, the reset member 18 can be an elastomer (rubber dome) and is arranged corresponding to the switch pad 162. When the keycap 12 is pressed and moved downward to squeeze the reset member 18, the trigger portion 182 of the reset member 18 can trigger the switch pad 162, but the present invention is not limited to this. The switch pad 162 can be triggered by a trigger portion, and the trigger portion can be set on the reset member 18, the lifting mechanism 14 or the keycap 12, etc. According to the actual application, the reset member 18 can be any element that can provide a restoring force to drive the keycap 12 to reset after being pressed, such as a spring, a magnetic member, etc. In this embodiment, the lifting mechanism 14 is a scissor-leg lifting mechanism, which has two brackets pivotally connected to each other, and the two ends of each bracket can be movably connected to the backlight circuit board 10 and the keycap 12, respectively, but the present invention is not limited to this. According to the actual application, the lifting mechanism 14 can be a butterfly-type lifting mechanism, a cantilever-type lifting mechanism, etc. The above constitutes the key unit of the backlight key 1 composed of the backlight circuit board 10, the keycap 12, the lifting mechanism 14 and the reset member 18. The backlight circuit board 10 of the present invention and the backlight module BL including the backlight circuit board 10 will be described in detail below.

[0035] Specifically, the backlight circuit board 10 is used to carry at least one keycap (e.g., keycap 12), and the backlight circuit board 10 may include a substrate 110, a switch circuit 160, a light-emitting circuit 120, and a light source 130. The substrate 110 has a plurality of holes 113 and a plurality of connectors 115. The plurality of holes 113 penetrate the substrate 110 to allow light emitted by the light source 130 to pass through, thereby illuminating the keycap 12. Specifically, the substrate 110 has a plurality of ribs 117 to define the plurality of holes 113, and the shape, number, and position of the ribs 117 and the holes 113 may be determined based on factors such as the structural strength of the backlight key 1, the position of the light emitting area 122 of the keycap 12, and the power of the light source 130. The plurality of connectors 115 are disposed on the substrate 110 and are used to directly or indirectly connect to the keycap 12. In this embodiment, the connector 115 can be a hook-shaped connector, and the lifting mechanism 14 is coupled to the connector 115 to connect the keycap 12 and the backlight circuit board 10, but the present invention is not limited thereto. Depending on the actual application, the connector 115 can be in the form of a slot, a column, etc.

[0036] In one embodiment, the substrate 110 may include a metal plate 112 and at least one insulating layer (e.g., an upper insulating layer 114U and a lower insulating layer 114B), wherein the at least one insulating layer at least partially covers the upper and lower surfaces of the metal plate 112. For example, the lower insulating layer 114B is disposed on the lower surface of the metal plate 112, with the surface (e.g., the lower surface) of the lower insulating layer 114B serving as the insulating surface 110a. The upper insulating layer 114U is disposed on the upper surface of the metal plate 112, with the surface (e.g., the upper surface) of the upper insulating layer 114U serving as the insulating surface 110b. The metal plate 112 may be a conductive substrate such as an aluminum alloy or steel plate, so that the metal plate 112 itself can shield radio waves and serve as a grounding component to reduce electrostatic discharge (ESD) issues. The upper insulating layer 114U and the lower insulating layer 114B can be applied to at least the upper and lower surfaces of the metal plate 112 by any suitable method, such as bonding, printing, coating, deposition, or molding, to form the insulating surfaces 110b / 110a on the upper and lower surfaces of the substrate 110. For example, the upper insulating layer 114U can be applied to the entire upper surface of the metal plate 112 or only to the portion of the upper surface of the metal plate 112 where the switch circuit 160 is to be arranged; the lower insulating layer 114B can be applied to the entire lower surface of the metal plate 112 or only to the portion of the lower surface where the light-emitting circuit 120 is to be arranged. In one embodiment (not shown), the insulating layer (e.g., the upper insulating layer 114U or the lower insulating layer 114B) can further cover the walls of the perforations 113 (or other through-holes), the sidewalls of the metal plate 112, and / or the surface of the connector 115 to prevent electrostatic discharge (ESD) issues caused by the exposed metal plate 112. Furthermore, the upper insulating layer 114U and the lower insulating layer 114B may comprise any insulating material capable of electrically isolating the metal plate 112 from the conductive circuit (e.g., the switch circuit 160 and the light-emitting circuit 120), such as a polymer material or a dielectric material. The upper insulating layer 114U and the lower insulating layer 114B may comprise the same or different insulating materials. When the substrate 110 is a metal plate 112, the connector 115 may be formed by, for example, the following methods: (1) stamping a planar connector from the metal plate and then bending the connector so that it stands on the surface of the metal plate; (2) insert molding a plastic connector onto the metal plate; or (3) hot-melting a preformed plastic connector onto the metal plate, but the present invention is not limited thereto.

[0037] In another embodiment, the substrate 110 may be a non-metallic plate, such as a non-conductive substrate made of glass fiber, carbon fiber, synthetic resin, polymer material, etc., and the insulating surfaces 110a and 110b may be the lower surface and upper surface of the non-metallic plate. When the substrate 110 is a non-metallic plate, the connector 115 may be fixed to the substrate 110 by, for example, the following methods: (1) using a mold to inject the substrate 110 with the connector 115 in one step; (2) using insert molding to form a plastic connector on the non-metallic plate; (3) using a hot melt method to fix the pre-formed plastic connector to the non-metallic plate; (4) fixing a metal frame with the connector 115 to the non-metallic plate; or (5) fixing the metal frame to the non-metallic plate and then fixing the pre-formed plastic connector to the metal frame by hot melt, but the present invention is not limited thereto.

[0038] Please also refer to Figure 2 and Figure 3 ,in, Figure 3 This is a bottom-up schematic diagram illustrating the configuration of the lower surface of the backlight circuit board around the light source according to one embodiment of the present invention. As shown, the switch circuit 160 is disposed on the upper surface of the substrate 110 (e.g., the insulating surface 110b). The switch circuit 160 includes switch pads 162, which trigger a key signal as the keycap 12 moves toward the substrate 110. The switch circuit 160 (including the switch pads 162) can be formed on the upper surface of the substrate 110 by printing (e.g., silver paste printing) or wire etching (e.g., copper foil etching). This allows the backlight circuit board 10 to integrate the switch circuit 160, serving simultaneously as the base plate of the key structure, the switch circuit board of the key structure, and the light source circuit board of the backlight module, effectively achieving a thinner key structure. It should be noted that when the switch circuit 160 is formed on the upper surface of the substrate 110, the switch pads 162, which serve as the switch unit, are preferably exposed toward the trigger portion 182, and the trigger portion 182 preferably has a conductive portion 182a. When the keycap 12 moves downward toward the backlight circuit board 10 , the trigger portion 182 moves downward accordingly, so that the conductive portion 182 a touches the switch pad 162 , thereby turning on the switch pad 162 and triggering a key signal.

[0039] The light-emitting circuit 120 is disposed on the lower surface (e.g., insulating surface 110a) of the substrate 110 and is located on the opposite side of the plurality of connectors 115 (i.e., the plurality of connectors 115 and the light-emitting circuit 120 are located on opposite sides of the substrate 110). Specifically, the connectors 115 (and the switching circuit 160) and the light-emitting circuit 120 are located on the upper surface (i.e., insulating surface 110b) and the lower surface (i.e., insulating surface 110a) of the substrate 110, respectively. The light-emitting circuit 120 can be formed on the insulating surface 110a by printing a metal paste (e.g., silver paste) or by etching a metal foil circuit from a solid sheet of metal foil (e.g., copper foil). The light-emitting circuit 120 can include a main circuit 121 and a sub-circuit 123, which are used to electrically connect the light source 130 and a driving element (not shown) so that the light source 130 can be driven to emit light.

[0040] The light source 130 is electrically connected to the light-emitting circuit 120 so as to receive power from the light-emitting circuit 120 to drive the light source 130 to emit light. For example, the light source 130 can be fixed to the light-emitting circuit 120 by a conductive adhesive layer to be electrically connected to the light-emitting circuit 120, but the present invention is not limited thereto. In another embodiment, the light source 130 can be fixed to the insulating surface 110a by a non-conductive adhesive layer and then electrically connected to the light-emitting circuit 120 by other conductive circuits. The light source 130 can be a single-chip or multi-chip light-emitting diode. In one embodiment, the light source 130 can be a side-emitting light-emitting diode, which has higher power. Although it consumes more electricity, it can transmit light farther. Therefore, the backlit keyboard KB only needs to be partially provided with a few light sources 130 to provide backlight to multiple keys KS or even all keys KS of the backlit keyboard KB, but the present invention is not limited thereto. In another embodiment, the light source 130 may be a micro light emitting diode having a five-sided light pattern, such as top light and four side light, so that a dedicated light source 130 can be set under any key KS that requires a backlight.

[0041] Furthermore, the backlight circuit board 10 optionally includes at least one protective layer (e.g., an upper protective layer 140U and a lower protective layer 140B). At least one of the protective layers is disposed on the substrate 110 to cover the switch circuit 160 and / or the light-emitting circuit 120. For example, the upper protective layer 140U is disposed on the insulating surface 110b and preferably covers the switch circuit 160 excluding the switch pads 162. The lower protective layer 140B is disposed on the insulating surface 110a and covers the light-emitting circuit 120. This provides waterproofing and insulation to the switch circuit 160 and the light-emitting circuit 120. In one embodiment, the upper protective layer 140U is preferably formed of a light-absorbing material (e.g., black paint or black ink), while the lower protective layer 140B may be formed of a reflective material (e.g., white paint or white ink), but the present invention is not limited thereto. Depending on the actual application, the upper protective layer 140U and the lower protective layer 140B may be formed of the same or different materials, for example, both may be formed of reflective materials. In one embodiment, the lower protective layer 140B preferably has a reflective surface 146 and / or a microstructure 144. The lower protective layer 140B is preferably formed of a reflective insulating material so that the lower surface of the lower protective layer 140B (i.e., the surface relatively far away from the insulating surface 110a) can serve as the reflective surface 146. In one embodiment, the lower protective layer 140B can be formed on the insulating surface 110a of the substrate 110 by white paint or white ink, for example, by printing. The lower protective layer 140B preferably covers all insulating surfaces 110a and the light-emitting circuit 120 except for the position of the light source 130, and has a larger reflective surface 146, which is conducive to recycling more light into the light guide plate 210. From another point of view, the lower protective layer 140B can be regarded as having an opening 142 (shown in FIG. Figure 3) is an insulating reflective film, and the opening 142 corresponds to the position of the light source 130, allowing the light source 130 to protrude from the opening 142 of the lower protective layer 140B toward the light guide plate 210. Furthermore, the lower protective layer 140B (or upper protective layer 140U) may have a through hole 148B (or 148U) at a position corresponding to the hole 113 of the substrate 110. This allows light to be emitted from the hole 113 of the substrate 110 (and the through hole 148U of the upper protective layer 140U) toward the keycap 12 through the through hole 148B, but the present invention is not limited thereto. Depending on the actual application, if the lower protective layer 140B (or upper protective layer 140U) is formed of a light-transmitting film, the protective layers (e.g., 140B, 140U) may not have a through hole. The reflective surface 146 of the lower protective layer 140B can be formed on the lower surface of the lower protective layer 140B using a reflective material or coating. The upper protective layer 140U can be provided with light-absorbing or light-reflecting capabilities by, for example, disposing a light-absorbing or light-reflecting material on a surface other than the surface corresponding to the aperture 113. In one embodiment, the reflective surface 146 preferably does not correspond to the location of the aperture 113 of the substrate 110. Specifically, in the stacking direction, the vertical projection of the aperture 113 and the reflective surface 146 preferably do not at least partially overlap, allowing light to escape from the aperture 113 of the substrate 110 through the lower protective layer 140B (or the through-hole 148B). In one embodiment, the microstructure 144 of the lower protective layer 140B preferably corresponds to at least one of the plurality of ribs 117 of the substrate 110, such that the microstructure 144 and the at least one rib 117 at least partially overlap in the stacking direction. On the other hand, the microstructures 144 of the lower protective layer 140B preferably correspond to the non-light emitting area 124 of the keycap 12, such that the microstructures 144 at least partially overlap with the non-light emitting area 124 of the keycap 12 in the stacking direction. The microstructures 144 preferably guide light toward the light guide plate 210 by reflection, scattering, or diffusion, thereby enhancing light recovery and lateral propagation.

[0042] The light guide 210 is disposed below the lower protective layer 140B, so that the light emitted by the light source 130 enters the light guide 210 and is transmitted laterally to illuminate the keycap 12. Specifically, the light guide 210 has a light hole 212, and the light source 130 is accommodated in the light hole 212. The light guide 210 can be a thin plate or sheet made of any suitable optical material (such as an optical polymer), and the light hole 212 is a through hole that passes through the thickness direction of the light guide 210, so that the light source 130 protrudes from the opening 142 of the lower protective layer 140B and can extend into the light hole 212. The light guide 210 also has a plurality of light emitting portions 214 for destroying total reflection to allow light to be emitted upward. The plurality of light emitting portions 214 are preferably arranged corresponding to the plurality of holes 113, but are not limited thereto. The light emitting portion 214 can be arranged at any suitable position where light is required to be emitted. The light emitting portion 214 may be any appropriate micro-optical structure, so that light transmitted to the light emitting portion 214 will be scattered upward.

[0043] The backlight module BL may optionally include a light shielding sheet 250, and the light shielding sheet 250 is disposed between the lower protective layer 140B and the light guide sheet 210. The light shielding sheet 250 has at least one light-transmitting window 252 corresponding to at least one keycap 12. Specifically, the light shielding sheet 250 is a light-transmitting film (such as polyethylene terephthalate (PET)), and the film has a light-shielding material (or coating material) to form a light-shielding coating 254 to define a plurality of light-transmitting windows 252. The light-shielding coating 254 can be a single layer or multiple layers structure for reflecting or absorbing light so that most of the light can be emitted from the light-transmitting window 252 into the hole 113 of the backlight circuit board 10. For example, the light-shielding material can include white paint (white ink) and / or black paint (black ink), but is not limited thereto. Depending on the actual application, the light-shielding coating 254 can be disposed on the upper surface and / or lower surface of the light shielding sheet 250. The light-shielding material can be any suitable optical material, and the light-shielding coating 254 can be formed by any suitable method (e.g., printing) to achieve the effects of partial light shielding and partial light transmission. In this embodiment, the light-shielding sheet 250 can have a light source through-hole 256. The light source through-hole 256 is arranged corresponding to the light source 130, so that the light source 130 can extend into the light hole 212 of the light guide sheet 210 through the light source through-hole 256. In one embodiment, the light-shielding sheet 250 preferably has a one-to-one light-transmitting window 252 corresponding to the indentation of the keycap 12 to improve the consistency of the halo at the edge of the keycap 12, but the present invention is not limited thereto.

[0044] Furthermore, in another embodiment, the light shielding sheet 250 can be integrated with the lower protective layer 140B. This allows the light shielding sheet 250 to not only provide partial light shielding and partial light transmission, but also serve as a protective layer for the light-emitting circuit 120. The lower protective layer 140B can be omitted, further reducing the overall thickness of the keypad. From another perspective, the lower protective layer 140B can be integrated with the light shielding sheet 250. This allows the lower protective layer 140B to not only protect the light-emitting circuit 120, but also provide partial light shielding and partial light transmission, serving as a light shield. This allows the light shielding sheet 250 to be omitted, further reducing the overall thickness of the keypad.

[0045] The backlight module BL may optionally include a reflective layer 220, and the reflective layer 220 is arranged on the other side (for example, below) of the light guide plate 210 relative to the light shielding plate 250 (that is, the reflective layer 220 and the light shielding plate 250 are located on opposite sides of the light guide plate 210). The reflective layer 220 is used to reflect light leaking from the bottom surface of the light guide plate 210 back to the light guide plate 210. Specifically, the reflective layer 220 can be a reflective film formed by a reflective material (for example, a metal foil), or a reflective film formed by coating a reflective material on a non-reflective film, or a plastic film doped with reflective particles (for example, a PET film doped with reflective particles), but is not limited thereto. In one embodiment, the reflective layer 220 can be a reflective film arranged on the lower surface of the light guide plate 210, but is not limited thereto. The reflective layer 220 can be further provided with a reflective layer microstructure 222 to guide light upward. For example, the reflective layer 220 may be provided with reflective layer microstructures 222 at locations corresponding to the light holes 212 of the light guide plate 210 to effectively reflect light emitted by the light source 130 and allow it to enter the light guide plate 210 through the sidewalls of the light holes 212 of the light guide plate 210, but the present invention is not limited thereto. The reflective layer microstructures 222 may be provided at any suitable location to increase light output or promote light recycling.

[0046] In addition, the backlight module BL may further include at least one adhesive layer (e.g., 236, 238, 231) for bonding the lower protective layer 140B, the light shielding sheet 250, the light guide sheet 210, and the reflective layer 220 to each other. Specifically, the light shielding sheet 250 and the lower protective layer 140B may be bonded to each other via the adhesive layer 236. For example, the adhesive layer 236 is disposed between the light shielding sheet 250 and the lower protective layer 140B around the light source 130, and preferably forms an adhesive-free area 236' between the light source through-hole 256 and the adhesive layer 236. The adhesive layer 236 is disposed on the top surface of the light shielding sheet 250 and is located around the light source through-hole 256, so that the light shielding sheet 250 and the light source 130 can be positioned by the adhesive layer 236, thereby improving the stability of optical coupling. There is a non-glue area 236 ′ between the glue layer 236 and the edge of the light source through hole 256 of the light shielding sheet 250 , ie, an area around the light source through hole 256 where no glue layer 236 is disposed, to prevent the glue layer 236 from entering the light source through hole 256 and interfering with light output.

[0047] The light shielding sheet 250 and the light guide sheet 210 can be bonded together by an adhesive layer 238. For example, the adhesive layer 238 is disposed between the light shielding sheet 250 and the light guide sheet 210, surrounding the light source 130. Preferably, an adhesive-free zone 238' is formed between the light source through-hole 256 (or light hole 212) and the adhesive layer 238. The adhesive layer 238 is disposed on the bottom surface of the light shielding sheet 250 and around the light source through-hole 256 (or light hole 212). This allows the light shielding sheet 250, the light guide sheet 210, and the light source 130 to be positioned by the adhesive layer 238, thereby improving the stability of optical coupling. There is a non-glue area 238 ′ between the glue layer 238 and the edge of the light source through hole 256 of the light shielding plate 250 (or the light hole 212 of the light guide plate 210 ), i.e., an area around the light source through hole 256 (or the light hole 212 ) where no glue layer 238 is disposed, to prevent the glue layer 238 from entering the light hole 212 and interfering with light output.

[0048] An adhesive layer 231 surrounds the light source 130 and is disposed between the light guide plate 210 and the reflective layer 220, forming an adhesive-free zone 233 between the light hole 212 and the adhesive layer 231. The adhesive layer 231 is disposed on the bottom surface of the light guide plate 210 and is positioned around the light hole 212. Specifically, the adhesive layer 231 is used to connect the light guide plate 210 and the reflective layer 220 and is positioned around the light hole 212 corresponding to the light source 130. This allows the light guide plate 210, the reflective layer 220, and the light source 130 to be positioned by the adhesive layer 231, thereby improving the stability of optical coupling. A adhesive-free zone 233 is defined between the adhesive layer 231 and the edge of the light hole 212 of the light guide plate 210. This is an area around the light hole 212 where the adhesive layer 231 is not disposed. This prevents the adhesive layer 231 from entering the light hole 212 and interfering with light output.

[0049] Furthermore, the adhesive layers 236, 238, or 231 can be formed from an adhesive material that is translucent and has a refractive index closer to that of air than that of the light guide plate 210. This allows a higher proportion of reflected light to enter the light guide plate 210 and undergo total internal reflection within the light guide plate 210. The vertical projections of the plurality of light exit portions 214 on the backlight circuit board 10 preferably do not overlap with the ribs 117. In this embodiment, the plurality of light exit portions 214 are preferably disposed outside the adhesive-free regions 236', 238', and 233 defined by the adhesive layers 236, 238, and 231 to increase the proportion of light transmitted laterally. From another perspective, the adhesive-free regions 236', 238', and 233 can be located between the light shielding plate 250 and the backlight circuit board 10, between the upper surface of the light guide plate 210 and the light shielding plate 250, or between the lower surface of the light guide plate 210 and the reflective layer 220. The vertical projections of the adhesive-free areas 236 ′, 238 ′, and 233 may at least partially overlap, or even completely overlap.

[0050] like Figure 2 and Figure 3As shown, the opening 142 of the lower protective layer 140B is preferably smaller than the light hole 212 of the light guide plate 210, but this is not limited to this. Furthermore, within the areas corresponding to the adhesive-free regions 236', 238', and 233, the microstructures 144 of the lower protective layer 140B preferably correspond to the reflective layer microstructures 222 of the reflective layer 220, such that the microstructures 144 and the reflective layer microstructures 222 at least partially overlap in the stacking direction. Furthermore, the reflective layer microstructures 222 of the reflective layer 220 are preferably disposed within the light hole 212 of the light guide plate 210 to reflect light emitted by the light source 130 and allow it to enter the light guide plate 210 from the sidewalls of the light hole 212. The switch circuit 160 and the light-emitting circuit 120 are respectively disposed on opposite sides (e.g., the top and bottom sides) of the substrate 110, and the switch pads 162 overlap with the light source 130 in a vertical projection on the backlight circuit board 10. Specifically, the switch circuit 160 and the light-emitting circuit 120 are respectively disposed on the upper side and the lower side (e.g., the upper surface and the lower surface) of at least one of the multiple ribs 117, and the vertical projections of the switch pad 162 and the light source 130 are preferably located within the range surrounded by the multiple connecting members 115 or even fall within the glue-free areas 236', 238', 233.

[0051] Please refer to Figure 4 and Figure 5 , Figure 4 This is a top view of a backlight circuit board corresponding to a single key according to an embodiment of the present invention. Figure 5 This is a bottom view of a backlight circuit board corresponding to a single key according to an embodiment of the present invention. Figure 4 and Figure 5 As shown, the light-emitting circuit 120 may include a main circuit 121 and a sub-circuit 123. The light-emitting circuit 120 is arranged on the insulating surface 110a (e.g., the bottom surface) of the substrate 110 and at least partially overlaps with the ribs 117. For example, the light-emitting circuit 120 may be arranged on the bottom surfaces of the frame ribs 117a, bridge ribs 117b, and island ribs 117c. To avoid light being blocked by the holes 113 in the substrate 110, the switch circuit 160 is preferably arranged at least directly above the ribs 117 of the substrate 110, for example, on the top surfaces of the frame ribs 117a, bridge ribs 117b, and island ribs 117c. Therefore, the vertical projection of the switch circuit 160 may at least partially overlap with the light-emitting circuit 120. For example, the switch circuit 160 may have a switch circuit segment and a light-emitting circuit segment of the light-emitting circuit 120, which are overlapped and arranged in the upper and lower projection ranges of the same frame rib 117a, bridge rib 117b, or center island rib 117c, and are partially parallel to each other. The switch pad 162 and the light source 130 are respectively arranged on the upper and lower sides of the center island rib 117c, so that the vertical projection of the switch pad 162 at least partially overlaps with the light source 130. Furthermore, if Figure 4As shown, there may be a gap GU between the upper protection layer 140U and the edge of the hole 113, so that the through hole 148U of the upper protection layer 140U is larger than the hole 113 of the substrate 110. Figure 5 As shown, a gap GB may be provided between the lower protective layer 140B and the edge of the opening 113, such that the through hole 148B of the lower protective layer 140B is larger than the opening 113 of the substrate 110, but this is not limiting. Depending on the actual application, the through hole 148U (or 148B) of the upper protective layer 140U (or lower protective layer 140B) may be larger than or equal to the opening 113. For example, the upper protective layer 140U (or lower protective layer 140B) may extend to the sidewall elevation of the opening 113 of the substrate 110.

[0052] Please refer to Figure 6A and Figure 6B , Figure 6A This is a bottom view schematic diagram of the configuration of the backlight circuit board and the lifting mechanism corresponding to multiple buttons according to an embodiment of the present invention. Figure 6B for Figure 6A Schematic diagram of the backlight circuit board without the lifting mechanism. Figure 6A and Figure 6B As shown, the light-emitting circuit 120 includes multiple main circuits 121 and multiple sub-circuits 123. The multiple main circuits 121 preferably extend parallel to the direction in which the keys are arranged, while the multiple sub-circuits 123 extend toward the light source 130 to electrically connect to the corresponding light source 130. In each key, a lifting mechanism 14 is coupled to the connector 115, and the vertical projection of the lifting mechanism 14 preferably falls within the area surrounded by the multiple holes 113. In one embodiment, the keycap 12 has a hook for direct connection to the connector 115 having a guided slot structure, in which case the lifting mechanism 14 is not required.

[0053] Please refer to Figure 7 , Figure 7 FIG. 1 is a top view of a backlight circuit board corresponding to multiple buttons according to an embodiment of the present invention. Figure 7 As shown, the switch circuit 160 is disposed along the surface of the substrate 110, and the switch pad 162 is disposed on the island rib (e.g., 117c). The switch pad 162 is preferably located within the vertical projection range of the reset member 18 (e.g., covered by an elastic body) to correspond to the trigger portion 182 (shown in FIG. 1 ) disposed on the reset member 18. Figure 2 On the other hand, the vertical projection of the switch pad 162 overlaps with the light source 130, so that the light source 130 can also be located within the vertical projection range of the reset member 18. The plurality of holes 113 preferably fall within the vertical projection range of the keycap 12 to enhance the appearance of the key or keyboard.

[0054] In summary, the present invention provides a backlight circuit board, a backlight module, a backlight key, and a keyboard. The backlight circuit board not only serves as the base plate of the key structure, but also incorporates a switching circuit and a lighting circuit, thereby serving as both the switch circuit board for the key structure and the light source circuit board for the backlight module. Furthermore, the backlight circuit board of the present invention integrates the key structure's switching circuit and the backlight module's lighting circuit into the key structure's base plate, effectively reducing the overall thickness of the key structure and promoting a thinner design.

[0055] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A backlight circuit board for carrying keycaps, characterized in that: The backlight circuit board contains: A substrate having a plurality of holes and a plurality of connectors, wherein the plurality of holes penetrate the substrate, the plurality of connectors are disposed on the substrate, and the plurality of connectors are used to directly or indirectly connect to the keycaps; A switch circuit is disposed on the substrate, the switch circuit having a switch pad, the switch pad triggering a key signal when the keycap moves toward the substrate; a light-emitting circuit, disposed on the substrate and located on the opposite side of the plurality of connecting members; as well as A light source electrically connected to the light emitting circuit, The vertical projections of the switch pad and the light source are both within the surrounding range of the plurality of connecting members.

2. The backlight circuit board according to claim 1, wherein: The substrate is a non-metal plate, so that the upper surface and the lower surface of the substrate are insulating surfaces.

3. The backlight circuit board according to claim 1, wherein: The substrate includes a metal plate and at least one insulating layer. The at least one insulating layer at least partially covers the upper surface and the lower surface of the metal plate.

4. The backlight circuit board according to claim 3, wherein: The at least one insulating layer at least covers the hole wall of at least one of the plurality of holes, the side wall of the metal plate and / or the surface of at least one of the plurality of connecting members.

5. The backlight circuit board according to claim 1, wherein: A vertical projection of the switch pad overlaps with the light source.

6. The backlight circuit board according to claim 1, wherein: A vertical projection of the switch circuit at least partially overlaps with the light-emitting circuit.

7. The backlight circuit board according to claim 1, wherein: The backlight circuit board further includes at least one protective layer, wherein the at least one protective layer is disposed on the substrate and covers the switch circuit and / or the light-emitting circuit.

8. The backlight circuit board according to claim 7, wherein: The substrate has a plurality of ribs to define the plurality of holes. The protection layer has a microstructure or the protection layer has a reflective surface and a microstructure. The microstructure overlaps with at least one of the plurality of ribs of the substrate.

9. The backlight circuit board according to claim 7, wherein: The keycap has a light emitting area and a non-light emitting area, the protective layer has a microstructure or the protective layer has a reflective surface and a microstructure, and the microstructure overlaps with the non-light emitting area of ​​the keycap.

10. The backlight circuit board according to claim 1, wherein: The substrate has a plurality of ribs to define the plurality of holes. The switch circuit and the light-emitting circuit are respectively arranged on the upper side and the lower side of at least one of the plurality of ribs.

11. A backlight module, characterized in that: The backlight module includes: The backlight circuit board according to any one of claims 1 to 10; and Light guide sheet, The light emitted by the light source enters the light guide plate and is transmitted laterally to illuminate the keycap.

12. The backlight module according to claim 11, wherein: The light guide plate has a light hole, and the light source is accommodated in the light hole.

13. The backlight module according to claim 12, wherein: The backlight module further comprises a glue layer, wherein the glue layer surrounds the light source and is disposed between the light guide plate and the substrate, and forms a glue-free area between the light hole and the glue layer.

14. The backlight module according to claim 11, wherein: The backlight module further comprises a reflective layer, wherein the reflective layer is arranged on the opposite side of the light guide plate relative to the substrate.

15. The backlight module according to claim 11, wherein: The backlight module further comprises a light shielding sheet, wherein the light shielding sheet is arranged between the substrate and the light guide sheet, and the light shielding sheet has at least one light-transmitting window corresponding to the keycap.

16. The backlight module according to claim 15, wherein: The light shielding plate has a light source through hole, the light guide plate has a light hole corresponding to the light source through hole, and the light source passes through the light source through hole and is accommodated in the light hole.

17. A backlight key, characterized in that: The backlit buttons include: The backlight circuit board according to any one of claims 1 to 10; and The keycaps.

18. A backlit keyboard, characterized in that: This backlit keyboard includes: The backlight circuit board according to any one of claims 1 to 10; and The keycaps.

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