TWI893652B - Illuminated keyswitch structure and illuminating module - Google Patents

Abstract

An illuminated keyswitch structure and an illuminating module thereof are provided. The illuminating module includes a drive circuit board having a reflector layer disposed thereon, a light-emitting part disposed on the drive circuit board and proximate to the reflector layer, a covering structure having an island-shaped covering portion, and a spacer adhered between the covering structure and the drive circuit board and having a through hole and an adhesive-less clearance fringe at least partially surrounding the through hole, wherein the island-shaped covering portion covers above the light-emitting part and the through hole.

Description

Luminescent key structure and illumination module

The present invention relates to a key structure, and more particularly to a light-emitting key structure and an illumination module.

This case is a continuation-in-part of and claims priority to U.S. Patent Application No. 18/353,925 (filed on July 18, 2023), which is a continuation-in-part of U.S. Patent Application No. 17/847,853 (filed on June 23, 2022), now a continuation-in-part of U.S. Patent Application No. 11,728,110, which is a continuation-in-part of U.S. Patent Application No. 17/234,808 (filed on April 20, 2021). This application is a continuation-in-part of U.S. Patent No. 11,764,004 and claims priority to Taiwan Patent No. 110100264 (filed on January 5, 2021), China Patent No. 202110441985.1 (filed on April 23, 2021), and U.S. Provisional Application No. 63/325,623 (filed on March 31, 2022). This application also claims priority to U.S. Provisional Application No. 63/446,794 (filed on February 17, 2023). The entire contents of the aforementioned patent applications are incorporated herein by reference and made a part of this specification.

Some illuminated key structures on the market feature a dedicated light source beneath their baseplate, emitting light upward. Openings are formed in the baseplate corresponding to the light source to allow light to pass through. To prevent electrostatic discharge between the baseplate and the light source and to protect the light source, an insulating sheet is typically attached to the light source and its circuit board. The light source typically protrudes from the circuit board, creating a protruding insulating sheet. This protrusion creates an uneven surface near the light source, hindering component assembly and overall thinness. Furthermore, the protruding insulating sheet will enter the opening of the baseplate, and even the light source will partially enter the opening. This structural configuration increases the chance of structural interference with the structural components above the baseplate (such as the bracket supporting the keycap), causing the keycap to be unable to move up and down smoothly or indirectly damaging the light source.

Furthermore, in illuminated keyboards, an illumination module is typically used to illuminate the keycap characters and keycap outlines. However, when the light source is located below the keycaps, the keycap characters directly above the light source appear too bright, while the characters farther from the light source (such as corner characters) and keycap outlines appear too dark, making it difficult to achieve uniform illumination between characters and keycap outlines.

One objective of the present invention is to provide a light-emitting key structure that utilizes a flat spacer to separate the base plate from the light-emitting element. This helps control structural dimensions, ensures light mixing distance, and protects the light-emitting element by preventing structural interference with components above the base plate, which could cause damage.

According to one embodiment of the present invention, the light-emitting key structure includes a base plate, a driving circuit board, a spacer, a light-emitting element, and a light-transmitting cover structure. The base plate has a plurality of openings and a plurality of ribs separating the plurality of openings; the driver circuit board is disposed below the base plate; a spacer is disposed below the base plate and above the driver circuit board, the spacer having a through hole; a light-emitting element is disposed on the driver circuit board and located in the through hole, the light-emitting element vertically corresponding to one of the openings in the base plate; the light-transmitting cover structure includes at least one first cover layer and at least one second cover layer; the first cover layer covers the light-emitting element and overlaps with a vertical projection of the one of the openings in the base plate; the second cover layer vertically corresponds to the light-emitting element and the one of the openings in the base plate, and the second cover layer blocks at least a portion of light emitted by the light-emitting element toward the one of the openings, thereby reducing the intensity of light emitted from the one of the openings.

In another embodiment, the first covering layer covers the driving circuit board in the through hole of the spacer.

In another embodiment, the through hole of the spacer is vertically connected to at least two openings of the bottom plate, and/or the through hole of the spacer is connected to at least two ribs of the bottom plate.

In another embodiment, the vertical projections of at least two openings of the first covering layer and the bottom plate overlap, and/or the vertical projections of at least two ribs of the first covering layer and the bottom plate overlap.

In another embodiment, the spacer includes a top sealant disposed on top and a bottom sealant disposed on the bottom; the overall thickness of the spacer, the top sealant, and the bottom sealant is greater than or equal to the sum of the height of the light-emitting element and the thickness of a portion of the light-transmitting cover structure located above the light-emitting element.

In another embodiment, the spacer includes a top sealant disposed on the top and/or a bottom sealant disposed on the bottom; the spacer further includes an annular clear edge on which no top sealant or bottom sealant is disposed, and the annular clear edge surrounds the periphery of the through hole of the spacer.

In another embodiment, the second covering layer further includes an upper light absorbing layer and a bottom reflective layer.

In another embodiment, the diameter of the upper light-absorbing layer may be smaller than the diameter of the bottom reflective layer.

In another embodiment, the first cover layer is achieved by constructing a flat first cover layer between the base plate and the spacer and not entering the through hole.

In another embodiment, the second covering layer further includes an upper light absorbing layer disposed on top of the flat first covering layer and a bottom reflecting layer disposed on the bottom of the flat first covering layer.

In another embodiment, the flat first covering layer includes a septum glue disposed thereon, and the flat first covering layer further includes an annular clear edge without the septum glue thereon, and the annular clear edge surrounds the periphery of the vertical projection of the through hole of the spacer.

In another embodiment, the second cover layer is reflective to reflect light back to the first cover layer located in the through hole of the spacer.

In another embodiment, at least one second cover layer is reflective and is shielded between one of the ribs of the base plate and the first cover layer to reflect light from the one of the ribs back to the first cover layer.

In another embodiment, the driving circuit board includes a plurality of reflective elements disposed thereon, wherein the plurality of reflective elements are vertically positioned corresponding to at least two openings of the base plate.

In another embodiment, the driving circuit board includes at least one surface reflector and multiple point reflectors. The surface reflector is disposed on the top of the driving circuit board, and the multiple point reflectors are located on the surface reflector and vertically correspond to at least two openings of the bottom plate.

In another embodiment, the luminous key structure further includes a key cap having at least one light-transmitting portion, wherein light passes through the plurality of openings in the base plate and illuminates the light-transmitting portion.

In a derivative embodiment, the light-emitting key structure includes a base plate, a driving circuit board, a spacer, a light-emitting element, and a transparent cover structure. The base plate has a plurality of openings and a plurality of ribs separating the plurality of openings; the driving circuit board is disposed below the base plate; the spacer is disposed below the base plate and disposed on the driving circuit board; the spacer has a through hole; the light-emitting element is disposed on the driving circuit board and is located in the through hole, and the light-emitting element vertically corresponds to one of the openings of the base plate; the transparent cover structure includes a flat first cover layer, a block first cover layer, and at least one second cover layer, wherein the block first cover layer covers the through hole of the light-emitting element and the spacer. The drive circuit board is housed within the substrate, and the block-shaped first cover layer further overlaps a vertical projection of one of the openings in the substrate; the planar first cover layer is constructed between the substrate and the spacer and does not enter the through-hole; and the second cover layer is at least partially disposed on the planar first cover layer and perpendicularly corresponds to the light-emitting element and one of the openings in the substrate. The second cover layer blocks at least a portion of light emitted by the light-emitting element toward the one of the openings, thereby reducing the intensity of light emitted from the one of the openings.

In another derivative embodiment, the driving circuit board includes a plurality of reflective elements disposed thereon, wherein the plurality of reflective elements are located at positions vertically corresponding to at least two openings of the base plate.

In another derivative embodiment, the driving circuit board includes at least one surface reflector and multiple point reflectors. The surface reflector is disposed on the top of the driving circuit board, and the multiple point reflectors are located on the surface reflector and vertically correspond to at least two openings of the bottom plate.

In another variant embodiment, the second cover layer is reflective to reflect light back to the first cover layer located in the through hole of the spacer.

In another embodiment of the present invention, a light-emitting key structure includes a base plate, a driver circuit board, a spacer, a light-emitting element, and a transparent cover structure. The base plate has an opening; the driver circuit board has a surface reflector and at least one point reflector disposed thereon; the spacer is bonded to the driver circuit board and has a through hole and a glue-free clear edge at least partially surrounding the through hole; the light-emitting element is disposed on the driver circuit board and adjacent to the surface reflector and the point reflector; the transparent cover structure covers the light-emitting element and includes a reflective layer, wherein the reflective layer reflects light from the light-emitting element toward the surface reflector and/or the point reflector, causing the light to be reflected upward from the surface reflector and/or the point reflector, pass through the through hole of the spacer, and then illuminate upward through the opening of the base plate.

In yet another embodiment of the present invention, an illumination module for illuminating a keypad includes a driver circuit board, a spacer, a light-emitting element, and a transparent cover structure. The driver circuit board has a surface reflector and at least one point reflector disposed thereon. The spacer is bonded to the driver circuit board and has a through hole and a clear, adhesive-free edge at least partially surrounding the through hole. The light-emitting element is disposed on the driver circuit board and between the surface reflector and the at least one point reflector. The transparent cover structure covers the light-emitting element and includes a reflective layer. The reflective layer reflects light from the light-emitting element, while the surface reflector and/or the at least one point reflector reflect light so that it passes through the through hole of the spacer and then radiates upward through the transparent cover structure.

In yet another embodiment of the present invention, an illumination module is used to illuminate a keypad and includes a driver circuit board, a light-emitting element, a transparent cover structure, and a spacer. The driver circuit board has a surface reflector and at least one point reflector disposed thereon; the light-emitting element is disposed on the driver circuit board and positioned between the surface reflector and the at least one point reflector; the transparent cover structure covers the light-emitting element and includes a reflective layer and a flat transparent layer, with the reflective layer reflecting light from the light-emitting element; and the spacer is bonded between the flat transparent layer and the driver circuit board. The spacer has a through hole and a clear, adhesive-free edge at least partially surrounding the through hole, such that one or both of the surface reflector and the at least one point reflector are at least partially positioned between the light-emitting element and the clear, adhesive-free edge.

In one embodiment, the reflective layer of the light-transmitting cover structure at least partially allows light to pass through.

In one embodiment, the reflective layer of the light-transmitting cover structure at least partially overlaps with the surface reflective element and/or at least one point reflective element.

In one embodiment, the light-transmitting covering structure further includes a flat transparent layer that covers the light-emitting element without entering the through hole.

In one embodiment, the spacer is bonded between the driving circuit board and the flat transparent layer of the light-transmitting cover structure.

In one embodiment, the through hole of the spacer overlaps with the opening of the base plate.

In one embodiment, the light absorbing layer is disposed above the reflective layer of the light-transmitting cover structure.

In one embodiment, the diameter of the light-absorbing layer is smaller than the diameter of the reflective layer.

In one embodiment, one or both of the surface reflector and the at least one point reflector are at least partially disposed between the light emitting element and the edge of the adhesive-free clear space.

In another variation of the present invention, an illumination module is used to illuminate a keypad and includes a driver circuit board, a light-emitting element, a covering structure, and a spacer. The driver circuit board has a reflective layer disposed thereon; the light-emitting element is disposed on the driver circuit board and adjacent to the reflective layer; the covering structure has an island-shaped covering portion; and the spacer is bonded between the covering structure and the driver circuit board. The spacer has a through hole and a clear, glue-free edge at least partially surrounding the through hole, wherein the island-shaped covering portion covers the light-emitting element and the through hole.

In one embodiment, the covering structure further includes a frame-shaped covering portion surrounding the island-shaped covering portion. The island-shaped covering portion extends to connect opposite sides of the frame-shaped covering portion to define two light-transmissive portions in the frame-shaped covering portion. The two light-transmissive portions surround the light-emitting element.

In one embodiment, the illumination module further includes a light-emitting pattern, wherein the light-emitting pattern includes a reflective pattern and a diffusion pattern. The reflective pattern is on the reflective layer, and the diffusion pattern is on the spacer. The light-emitting pattern is used to guide light upward to at least one of the two light-transmissive portions.

In one embodiment, each of the two light-transmitting portions has two or more corners and three or more side edges, such that each corner of the frame-shaped covering portion corresponds to one of the corners of the two light-transmitting portions.

In one embodiment, the covering structure includes a first covering layer and a second covering layer. The first covering layer is configured to substantially reflect light, and the second covering layer is configured to substantially block light. At least one of the first covering layer and the second covering layer forms an island-shaped covering portion, and the first covering layer and the second covering layer together form a frame-shaped covering portion.

In one embodiment, the covering structure further includes a planar covering layer, the first covering layer and the second covering layer are disposed on the same side or on opposite sides of the planar covering layer, and the first covering layer is closer to the spacer than the second covering layer.

In one embodiment, the second covering layer extends from the first covering layer to at least partially surround at least one of the two light-transmissive portions.

In another derivative embodiment, the light-emitting key structure includes a base plate, a key cap and an illumination module, wherein the base plate has an opening; the key cap is arranged relative to the base plate; the illumination module includes: a driving circuit board, a light-emitting element, a covering structure and a spacer, wherein the driving circuit board has a reflective element layer thereon; the light-emitting element is arranged on the driving circuit board and adjacent to the reflective element layer; the covering structure The structure comprises a frame-shaped covering portion and an island-shaped covering portion. A spacer is bonded between the covering structure and the driver circuit board. The spacer has a through hole and a glue-free clear edge. The through hole corresponds to the opening, and the glue-free clear edge at least partially surrounds the through hole. The frame-shaped covering portion is disposed around the outline of the keycap, and the island-shaped covering portion covers the light-emitting element and the through hole.

In one embodiment, each of the two light-transmissive portions has two or more corners and three or more side edges, such that each corner of the keycap corresponds to one of the corners of the two light-transmissive portions.

In one embodiment, each of the two light-transmissive portions has two or more corners and three or more side edges, and each side edge of the keycap corresponds to at least one of the side edges of the two light-transmissive portions.

In one embodiment, the base plate further has two or more peripheral openings disposed around the opening, and each of the two light-transmissive portions at least partially corresponds to at least one of the two or more peripheral openings.

In one embodiment, the illumination module further includes a light-emitting pattern corresponding to the two light-transmitting portions and configured to guide light upward through at least one of the two light-transmitting portions and further through two or more peripheral openings.

In one embodiment, the keycap has multiple light-transmitting portions, and one of the two light-transmitting portions is located between two of the multiple light-transmitting portions.

In one embodiment, the keycap has multiple light-transmitting portions, and one of the two light-transmitting portions is located between one of the multiple light-transmitting portions and the outline of the keycap.

In another derivative embodiment, an illumination module is used to illuminate a key, and includes a driver circuit board, a light-emitting element, a covering structure, a spacer, and a light-emitting pattern. The driver circuit board has a reflective layer disposed thereon; the light-emitting element is disposed on the driver circuit board and adjacent to the reflective layer; the covering structure has an island-shaped covering portion; the spacer is bonded between the covering structure and the driver circuit board, and the spacer has a through hole and a glue-free clear edge that at least partially surrounds the through hole; the light-emitting pattern includes a reflective pattern and a diffusion pattern, the reflective pattern is on the reflective layer, and the diffusion pattern is on the spacer, wherein the island-shaped covering portion covers the light-emitting element and the through hole, and the light-emitting pattern is actually disposed adjacent to the island-shaped covering portion and is used to guide light upward.

According to an embodiment of the present invention, for illuminated keys with dedicated low-illuminance light-emitting elements, the lighting uniformity of the entire keycap can be enhanced. Furthermore, the illumination loss caused by light directed toward the ribs of the base plate can be resolved by a corresponding reflective second cover layer. In addition, a larger block-shaped first cover layer is introduced to cover the light-emitting elements within the through-holes of the spacer elements. The block-shaped first cover layer is large enough to overlap the vertical projections of at least two of the multiple openings in the base plate. Such a block-shaped first cover layer can have a reflective element underneath to reflect the recycled light toward the light-transmitting portions in the corners of the keycap, thereby improving the illumination uniformity. A flat first cover layer can be used with or without a blocky first cover layer to optimize the illumination uniformity of illuminated keys with low-intensity lighting elements.

The above and other objects of the present invention will no doubt become apparent to those skilled in the art after reading the following detailed description of the preferred embodiments shown in the various drawings and accompanying drawings.

1: Luminous button structure

10: Base Plate

102: Bottom

104: Opening

104’: Peripheral openings

106: Ribs

12: Keycaps

120, 120a, 120b: Translucent portion

14: Lifting mechanism

16: Switch circuit board

162: Switch

164: Perforation

18: Elastic return element

20: Driver circuit board

202: Upper surface

204: Circuit

206: Connecting pad

208: Reflective element

208a: Point reflector

208b: Reflection pattern

211: Main Layout

212: Sub-wiring

22: Luminous parts

222: Top

224:Side

24: Spacer

24a: Diffusion pattern

242, 242’: Through hole

242a, 242b, 242c, 242d: Side walls

244: Upper surface

244a: Annular clear edge

244b: Clear Space Outer Edge

246: Lower surface

246a: Annular clear edge

246b: Clear Space Outer Edge

26, 26’: Top glue

28, 28': Base glue

30, 30a, 30b, 30c: Translucent covering structure

30’: Covering structure

30a’: Island-shaped covering part

30b’: Frame-shaped covering portion

302, 302’: First covering layer

3021:Edge

304, 304’: Second covering layer

3041:Edge

306: Flat first covering layer

306’: Flat cover layer

306a: Annular clear edge

306b: Translucent portion

308: Septum glue

A:Circle

D1: Vertical direction

Figure 1 is an exploded view of a luminous key structure according to one embodiment.

Figure 2 is a cross-sectional view of the luminous key structure in Figure 1.

Figure 3 is an enlarged view of circle A in Figure 2.

Figure 4 is a schematic diagram of an embodiment of the coating range of the top glue on the spacer.

Figure 5 is a schematic diagram of an embodiment of the primer coating area on the spacer.

Figure 6 is a cross-sectional view of an embodiment of a through hole in a spacer.

Figure 7 is a cross-sectional view of another embodiment of a through hole in a spacer.

Figure 8 is a cross-sectional view of another embodiment of a through hole in a spacer.

Figure 9 is a cross-sectional view of an embodiment of a light-transmitting cover structure located within a through-hole of a spacer.

Figure 10 is a cross-sectional view of another embodiment of a light-transmitting cover structure located within a through-hole of a spacer.

Figure 11 is a cross-sectional view of a variation of the luminous key structure.

Figures 12A, 12B, and 12C are schematic diagrams of example patterns of the second covering layer in certain variations.

Figure 13 is a cross-sectional view of a luminous key structure according to another variation.

Figure 14 is an exploded view of a luminous key structure according to another variation.

Figure 15 is a cross-sectional view of the light-emitting key structure of Figure 14.

Figure 16 is a cross-sectional view of a luminous key structure according to a derivative example.

Figure 17 is a cross-sectional view of another variation of the luminous key structure.

Figures 18 to 21 are schematic plan views of the components of the luminous key structure of Figure 17.

Figure 22 is a schematic plan view of the stacking of certain components of the luminous key structure of Figure 17.

Please refer to Figures 1 to 3. According to one embodiment, a light-emitting key structure 1 includes a base plate 10, a keycap 12, a lifting mechanism 14, a switch circuit board 16, an elastic reset member 18, a drive circuit board 20, a light-emitting member 22, and a spacer 24. The keycap 12 is disposed on the base plate 10. The lifting mechanism 14 is connected between the base plate 10 and the keycap 12, allowing the keycap 12 to move up and down relative to the base plate 10. The switch circuit board 16 is disposed on the base plate 10 and has a switch 162 (indicated by a hatched circle in Figure 1). The elastic reset member 18 is disposed between the keycap 12 and the switch 162, corresponding to the switch 162. The keycap 12 can be pressed downward to squeeze the elastic reset member 18, causing the elastic reset member 18 to trigger the switch 162. The switch 162 can be triggered by a trigger bump located above the switch circuit board 16. The trigger bump extends from any component located above the switch circuit board 16, such as the elastic reset member 18, the lifting mechanism 14, or the keycap 12. When the keycap 12 is not pressed, the rebound force of the elastic reset member 18 causes the keycap 12 to move upward and return to its original position. The lifting mechanism 14 is implemented by a scissor-leg bracket, which includes two brackets that are individually connected between the base plate 10 and the keycap 12 and are pivotally connected to each other. The switch circuit board 16 is implemented as a thin film circuit board, comprising an upper circuit board, a lower circuit board, and an intermediate insulating plate disposed between the upper and lower circuit boards. The switch is implemented by circuit contacts located opposite each other on the upper and lower circuit boards. The elastic reset member 18 can be implemented, for example, but not limited to, a rubber protrusion.

In practice, the lifting mechanism 14, the switch circuit board 16, and the elastic reset member 18 can also be implemented by other structures that can produce the same effect. For example, the lifting mechanism 14 can be implemented by a butterfly bracket or other mechanism that can provide a corresponding keycap to move up and down. In practice, the lifting mechanism of a longer keycap (such as a blank key, input key, reverse key, shift key, etc.) can be implemented by multiple scissor-foot brackets, butterfly brackets, or a combination thereof. For another example, the switch circuit board 16 can be implemented by a circuit board with a touch switch. For another example, the switch circuit board 16 can be implemented by a printed circuit board or a flexible circuit board, on which two adjacent contacts are formed as a switch 162. The elastic reset member 18 has a conductive portion corresponding to the two contacts and can simultaneously contact the two contacts through the conductive portion to trigger the switch 162. For example, the elastic reset member 18 can be implemented by a spring or other elastic structure.

Furthermore, in this embodiment, the driver circuit board 20 is disposed below the base plate 10 and has an upper surface 202. A light-emitting element 22 is electrically disposed on the upper surface 202 of the driver circuit board 20. The light-emitting element 22 can be a single single-color LED (e.g., white) or multiple LEDs of different colors (e.g., red, green, and blue). A spacer 24 is disposed between the base plate 10 and the driver circuit board 20. The base plate 10 has a bottom surface 102 and one or more openings 104/104'. The switch circuit board 16 has a through hole 164. The spacer 24 has a through hole 242. The opening 104 of the base plate 10, the through-hole 164 of the switch circuit board 16, and the through-hole 242 of the spacer 24 are connected in the vertical direction D1 (as shown by the double arrows in the figure). The projections of the three in the vertical direction D1 can be completely aligned or at least partially overlap. In other words, the opening 104, the through-hole 164, and the through-hole 242 at least partially overlap in the vertical direction D1, so that a straight channel exists in the vertical direction D1, passing through the opening 104, the through-hole 164, and the through-hole 242. In other embodiments, the switch circuit board 16 is light-transmissive except for the circuitry, and the through-hole 164 is not absolutely necessary. The light-emitting element 22 has a top surface 222 and is located in the through-hole 242. The top surface 222 is lower in height than the bottom surface 102 of the base plate 10. This allows the illuminated key structure 1 to remain flat near the light-emitting element 22, facilitating structural size control. Furthermore, in other embodiments, the light-emitting element 22 and through-hole 242 may be located at positions corresponding to other openings 104' of the base plate 10. In larger multi-layer keys, or keys requiring an additional indicator light source, multiple light-emitting elements 22 may be located in corresponding openings 104 and 104' of the base plate 10.

The spacer 24 also prevents the light-emitting element 22 from structurally entering the opening 104 of the base plate 10, thereby preventing structural interference between the light-emitting element 22 and other components within the light-emitting key structure 1 located above the base plate 10 (for example, components that might temporarily enter the opening 104 during operation), potentially causing damage. Furthermore, in this embodiment, the spacer 24 is plate-shaped and conforms to the contour of the driver circuit board 20. This structural configuration further helps maintain a flat overall structure of the base plate 10, driver circuit board 20, and spacer 24, but this is not a limitation in practice. For example, the spacer 24 may be annular (e.g., circular, square, or other geometrically shaped) surrounding the light-emitting element 22, while still maintaining the flatness of the light-emitting key structure 1 near the light-emitting element 22. Furthermore, in practice, the switch circuit board 16 may be disposed beneath the base plate 10 and structurally integrated with the driver circuit board 20 into a single circuit board. For example, the switch circuit board 16 may be removed, and a touch switch may be provided on the driver circuit board 20 at a location corresponding to the trigger bump extending from any of the elastic reset member 18, the lift mechanism 14, or the keycap 12. A corresponding opening is formed in the base plate 10 to allow the elastic reset member 18 to move downward and contact the touch switch.

In this embodiment, the sidewalls 242a of the through-hole 242 in the spacer 24 surround the light-emitting element 22 and are sufficiently close to the side surfaces of the light-emitting element 22. The top of the sidewalls 242a are also higher than the light-emitting element 22 to protect it. Therefore, regardless of whether the light-emitting element 22 is covered with insulating material, it is protected from interference and impact during assembly or operation. Furthermore, the sidewalls 242a of the through-hole 242 are opaque, preventing light emitted by the light-emitting element 22 from entering the spacer 24, thus preventing unintended sidelight leakage around the keys or keyboard. In practice, when the spacer 24 is made of a light-transmitting material, the sidewalls 242a can be coated with an opaque layer. Alternatively, the spacer 24 can be made directly of opaque material, rendering the entire spacer 24 opaque. Furthermore, in this embodiment, the through-hole 242 of the spacer 24 is larger than the opening 104 of the base plate 10 (for example, in the vertical direction D1, the projection of the opening 104 falls within the projection of the through-hole 242, and the light-emitting element 22 falls within the projection of the opening 104). This helps prevent light reflected from the sidewalls 242a of the through-hole 242 from being emitted directly from the opening 104. Furthermore, the through-hole 164 of the switch circuit board 16 is larger than the opening 104 of the base plate 10 (for example, the projection of the opening 104 in the vertical direction D1 falls within the projection of the through-hole 164). This helps prevent light emitted from the opening 104 from entering the switch circuit board 16 through the sidewalls of the through-hole 164. In other embodiments, the size of the openings 104/104' in the base plate 10 does not necessarily need to be smaller than the size of the through-hole 242 in the spacer 24, as long as their projections in the vertical direction D1 at least partially overlap, and the light-emitting element 22 completely falls within the projection of the openings 104/104' in the base plate 10 in the vertical direction D1 and is not directly blocked by the base plate 10.

Furthermore, in this embodiment, the light-emitting key structure 1 includes a top adhesive 26 and a bottom adhesive 28 (not shown in FIG. 1 to simplify the diagram) to bond the spacer 24 to the base plate 10 and the driver circuit board 20, respectively. The spacer 24 has an upper surface 244 and a lower surface 246 opposite the upper surface 244. The top adhesive 26 is disposed between the upper surface 244 and the bottom surface 102 of the base plate 10. The top adhesive 26 avoids all openings 104/104' of the base plate 10. The spacer 24 is fixedly connected to the base plate 10 via the top adhesive 26 (i.e., the top adhesive 26 adheres to the upper surface 244 and the bottom surface 102 of the base plate 10). The base glue 28 is disposed between the lower surface 246 and the upper surface 202 of the driver circuit board 20. The spacer 24 is fixedly connected to the driver circuit board 20 via the base glue 28 (i.e., the base glue 28 adheres to the lower surface 246 and the upper surface 202 of the driver circuit board 20). Furthermore, the top glue 26 and the base glue 28 are also made of opaque materials to prevent light from entering the top glue 26 and the base glue 28.

In practice, the spacer 24 can first be coated with a top glue 26 and a bottom glue 28 on its upper surface 244 and lower surface 246, respectively. The spacer 24 is then bonded to the driver circuit board 20 via the bottom glue 28. Finally, the spacer 24 is bonded to the base plate 10 via the top glue 26. Generally speaking, the top glue 26 and bottom glue 28 do not overflow into the through hole 242 of the spacer 24 and contact the sidewall 242a of the through hole 242 or the light-emitting element 22. In this embodiment, the coating area of the top glue 26 on the upper surface 244 is shown as the hatched area in Figure 1, which corresponds to the projection area of the base plate 10 on the upper surface 244. After bonding, the top adhesive 26 is not exposed; that is, the bottom plate 10 and the spacer 24 are completely covered by the top adhesive 26. Furthermore, the bottom surface 246 of the spacer 24 can completely fall on the top surface 202 of the driver circuit board 20 in the vertical direction D1. Therefore, the bottom adhesive 28 is applied to the entire area of the bottom surface 246 of the spacer 24 outside the area corresponding to the light-emitting element 22, or in other words, the bottom adhesive 28 is applied to the entire area of the bottom surface 246 of the spacer 24 outside the area corresponding to the through hole 242. Similarly, after bonding, the bottom adhesive 28 is not exposed; that is, the driver circuit board 20 and the spacer 24 are completely covered by the bottom adhesive 28. However, this is not a limitation in practice. Furthermore, in the variation shown in Figure 4 , the top adhesive 26' (its thickness is shown exaggerated in the figure) is applied in a grid pattern on the upper surface 244 of the spacer 24. After bonding, the top adhesive 26' still completely covers the base plate 10. In practice, the grid pattern is not limited to that shown in Figure 4 . The grid pattern facilitates the application of the top adhesive 26', preventing it from overflowing from between the spacer 24 and the base plate 10 and interfering with the operation of other components (e.g., contact with the bracket of the lift mechanism 14) or assembly (e.g., contact with the outer casing of the illuminated key structure 1 (not shown)).

Furthermore, as shown in FIG4 , the upper surface 244 has an annular clear edge 244a surrounding the through-hole 242. The annular clear edge 244a is free of the top glue 26' (i.e., there is no clear edge), which prevents the top glue 26' from overflowing from between the spacer 24 and the base plate 10 and entering the through-hole 242 of the spacer 24 or the opening 104 of the base plate 10. Furthermore, the upper surface 244 has a clear outer edge 244b. The clear outer edge 244b is also free of the top glue 26', which prevents the top glue 26' from overflowing from between the spacer 24 and the base plate 10. Similarly, in the variation shown in FIG5 , primer 28 ′ (its thickness is shown exaggerated in the figure) is applied in a grid pattern on the lower surface 246 of the spacer 24. Lower surface 246 has an annular clear edge 246 a and a clear outer edge 246 b. Annular clear edge 246 a surrounds through-hole 242. There is no primer 28 ′ on annular clear edge 246 a, nor on clear outer edge 246 b. The grid pattern of primer 28 ′ also produces the same effects as the grid pattern of top glue 26 ′ described above, and will not be further described. Alternatively, in practice, the top and bottom adhesives can be applied as discrete dots on the upper and lower surfaces 244 and 246 of the spacer 24, similarly bonding the spacer 24 to the base plate 10 and driver circuit board 20. Furthermore, with the trend toward thinner light-emitting key structures, the distance between the light-emitting element 22 and the keycap 12 is gradually decreasing. When the light-emitting element 22 is a combination of multiple LEDs of different colors, the distance between the light-emitting element 22 and the keycap 12 may be too small, resulting in insufficient light mixing distance for white light or a specific color. Therefore, adjusting the thickness of the spacer 24, or adjusting the total thickness of the spacer 24/top glue 26 (26')/bottom glue 28 (28'), helps adjust the light mixing distance so that the multi-colored light emitted by the light-emitting element 22 can have a sufficient light mixing distance and can achieve the target color light mixing effect before passing through the key cap 12. In terms of the protection effect of the light-emitting element 22, the total thickness of the spacer 24/top glue 26 (26')/bottom glue 28 (28') (starting from the top surface of the driver circuit board 20, the same below), or the height of the side wall 242a of the through hole 242 plus the thickness of the top glue 26 (26') and the thickness of the bottom glue 28 (28'), should be greater than or equal to the height of the light-emitting element 22.

Returning to Figures 1 to 3 , in this embodiment, the light-emitting key structure 1 further includes a transparent cover structure 30 that covers the light-emitting element 22 . The light-emitting element 22 may be, for example, but not limited to, a light-emitting diode. The light-emitting element 22 emits light from a top surface 222 (i.e., emits light upward). The light-emitting element 22 has a side surface 224 (i.e., a sidewall surface adjacent to and surrounding the top surface 222 ). The transparent cover structure 30 covers the top surface 222 and side surfaces 224 of the light-emitting element 22, as well as the upper surface 202 of the driver circuit board 20. This allows the transparent cover structure 30 to simultaneously modulate the light emitted by the light-emitting element 22 and secure the light-emitting element 22 to the driver circuit board 20. The portion of the transparent cover structure 30 above the top surface 222 can be considered a light modulating portion (shown by a dashed frame in FIG. 3 ), which modulates the light emitted by the light-emitting element 22. This light modulating portion has an upwardly facing protrusion that provides a light-concentrating effect, but this is not a limitation in practice. In this embodiment, the connection pads 206 of the circuit 204 of the driver circuit board 20 are exposed through the through-holes 242 of the spacer 24, and the light-emitting element 22 is electrically connected to the connection pads 206. The transparent cover structure 30 covers both the connection pads 206 and the portion of the circuit 204 exposed through the through-holes 242, thus providing electrostatic discharge protection.

Furthermore, in this embodiment, the highest point of the light-transmitting cover structure 30 is approximately equal to the bottom surface 102 of the base plate 10, thereby avoiding structural interference with other components within the light-emitting key structure 1 located above the base plate 10. The light-transmitting cover structure 30 may also be lower than the bottom surface 102. Furthermore, in practice, the light-transmitting cover structure 30 may be implemented by dispensing glue (for example, after the spacer 24 is fixed to the driver circuit board 20) or by other means (for example, by assembling it to the light-emitting element 22 using a separate component). Furthermore, the light-emitting key structure 1 may also be implemented without the light-transmitting cover structure 30 covering the light-emitting element 22. In this case, the top surface 222 of the light-emitting element 22 may also be at the same height as the bottom surface 102 of the base plate 10.

In this embodiment, the light-transmitting cover structure 30 includes a first cover layer 302 and a second cover layer 304. The first cover layer 302 is disposed on the top surface 222, and the second cover layer 304 is disposed on the first cover layer 302. The first cover layer 302 covers the top surface 222, side surfaces 224, and connection pads 206 of the light-emitting element 22. The second cover layer 304 is disposed on the first cover layer 302 relative to the top surface 222, but this is not a limitation in practice. For example, the second cover layer 304 may cover the entire first cover layer 302. Furthermore, in practice, the first cover layer 302 or the second cover layer 304 can be a wavelength conversion layer, such as, but not limited to, a layer containing phosphor or quantum dots. Furthermore, the transparent cover structure 30 can also be a single-layer structure or a multi-layer structure.

Furthermore, in this embodiment, the light-transmitting cover structure 30 does not completely fill the through hole 242, resulting in a gap between the light-transmitting cover structure 30 and the sidewall 242a of the through hole 242. As shown in FIG3 , an air barrier is formed between the light-transmitting cover structure 30 and the sidewall 242a of the through hole 242, surrounding the side surface 224; however, this is not a limitation in practice. For example, in the variation shown in FIG6 , the sidewall 242b of the through hole 242′ is capable of reflecting light and is in the form of a cup-shaped structure with an opening facing upward (i.e., toward the opening 104 of the base plate 10). This helps guide the light emitted by the light-emitting element 22 upward. In this embodiment, the sidewall 242b is entirely concave. However, this is not a limitation in practice. For example, the side wall 242c is a cone (as shown in FIG7 ); for another example, the side wall 242d is a stepped surface (as shown in FIG8 ); for another example, the side wall may be other structures that can guide light upward. The aforementioned concave surface, cone surface, and stepped surface can be realized by hot pressing in practice. In addition, as shown in FIG6 , the light-transmitting covering structure 30a is filled with through holes 242 ' and is roughly coplanar with the bottom surface 102 of the base plate 10, but is not limited to this in practice. For example, the light-transmitting covering structure 30b has an upward convex portion (as shown in FIG9 ). For another example, a microstructure (such as a saw-tooth structure, as shown in FIG10 ) is formed on the surface of the light-transmitting covering structure 30c. Similarly, the aforementioned light-transmitting covering structure 30a and light-transmitting covering structure 30b can also be multi-layer structures, which will not be elaborated. The outlines of the light-transmitting covering structure 30a and light-transmitting covering structure 30b can also be realized through hot pressing. In terms of the protective effect of the light-emitting element 22, the total thickness of the spacer 24/top glue 26 (26')/bottom glue 28 (28'), or the height of the side wall 242a of the through hole 242 plus the thickness of the top glue 26 (26') and the thickness of the bottom glue 28 (28'), should be greater than or equal to the height of the light-emitting element 22 plus the total thickness of the light-transmitting covering structure 30 (or the light-transmitting covering structure 30a/30b) located above the light-emitting element 22.

Furthermore, as shown in Figures 1 through 3 , in the luminous key structure 1 , the elastic reset element 18 is translucent. This allows light emitted by the luminous element 22 to travel toward the keycap 12 even when the luminous element 22 is located below the elastic reset element 18 , thereby providing full backlighting for the translucent portion 120 of the keycap 12 (indicated by a dashed frame in Figures 1 and 2 ; e.g., numbers, symbols, letters, text, graphics, or combinations thereof). Furthermore, in this embodiment, the luminous element 22 emits light from the top surface 222 , but this is not a limitation. For example, the luminous element 22 can also be side-emitting, and in combination with cup-shaped through-hole sidewalls (e.g., sidewalls 242b-d), the light emitted by the luminous element 22 can still be effectively guided toward the keycap 12 .

Referring to Figure 1 , for a single, thin, illuminated key 1, its dedicated light-emitting element 22 is constructed very close to the keycap 12. Only low illumination is required to illuminate the keycap 12. However, while this successfully reduces power consumption, uniform illumination across the entire keycap 12 can become a significant issue. For example, the light-transmitting portion 120 on the inner side of the keycap 12 (i.e., in the center area of the keycap 12) may have the brightest intensity, while the light-transmitting portions 120 at the four corners may be much dimmer.

Please refer to Figure 11, which is a cross-sectional view of a light-emitting key structure according to a modified embodiment. In Figure 11, the low-illumination light-emitting element 22 is disposed within a single large through-hole 242 of the spacer 24. The light-emitting element 22 corresponds vertically to one of the openings 104 or 104' of the base plate 10. The size of the single through-hole 242 can overlap with most of the projected area of the key cap 12. The size of the single through-hole 242 is sufficient to communicate with at least two or more of the openings 104' and the inner opening 104 at the four corners of the base plate 10 in Figure 1. In other words, the large through-hole 242 overlaps with the vertical projections of the multiple ribs 106 of the base plate 10. Alternatively, a single through hole 242 at least partially overlaps with at least one of the four corner openings 104' and also at least partially overlaps with the inner opening 104 of the base plate 10. Of course, a single through hole 242 at least partially overlaps with one or more ribs 106 of the base plate 10. Similarly, the light-transmitting cover structure 30 includes a first cover layer 302 and a second cover layer 304. Both the first cover layer 302 and the second cover layer 304 can be light-transmitting. Alternatively, the first cover layer 302 can be light-transmitting, while the second cover layer 304 can be at least partially light-transmitting, absorbing or reflecting some of the light. The block-shaped first cover layer 302 is not only disposed on the top surface 222 of the light-emitting element 22, but also covers at least a majority of the through-hole 242 and the top surface of the driver circuit board 20 within the through-hole 242. This ensures that the first cover layer 302 at least partially overlaps with the vertical projections of each of the four corner openings 104' and the inner opening 104 of the base plate 10. A second cover layer 304 is disposed on the first cover layer 302 and corresponds to the light-emitting element 22. The second cover layer 304 at least partially overlaps with the vertical projection of the inner opening 104. In other words, the second cover layer 304 is disposed between the light-emitting element 22 and the opening 104 or 104' of the base plate 10, and is perpendicular to the light-emitting element 22 and the opening 104 or 104' of the base plate 10. The diameter of the second cover layer 304 is larger than the diameter of the light-emitting element 22, but can also be smaller than the diameter of the inner opening 104 to allow light to pass through the gap between the rib 106 of the base plate 10 and the second cover layer 304. In a variant embodiment, the second cover layer 304 can have the same diameter as the inner opening 104. Both the first cover layer 302 and the second cover layer 304 can be at least partially light-transmissive to allow light emitted by the light-emitting element 22 to pass through. The first cover layer 302 can be made of a highly translucent, curable gel material to allow light to propagate within the first cover layer 302. Under certain conditions (e.g., curing the first cover layer 302 to achieve a smooth, hard, and flat surface), some light can be totally internally reflected within the first cover layer 302, allowing the light to propagate laterally therein, thereby reducing the amount of light that passes through the openings 104 on the inner side of the base plate. The majority of the light from the light-emitting element 22 can be widely diffused to the openings 104' at all four corners of the base plate 10 and the vertical projection of the openings 104 on the inner side. Therefore, the light passing through the light-transmitting portions 120 at the four corners of the keycap 12 has an illumination level comparable to that of the light-transmitting portions 120 on the inner side, thereby achieving uniform illumination across all light-transmitting portions 120 of the keycap 12.

The second covering layer 304 can be implemented by a plastic sheet or an ink coating, which is disposed on the first covering layer 302 and aligned with the light-emitting element 22. Referring to Figures 12A, 12B, and 12C, each is a schematic diagram of an example pattern of the second covering layer 304 according to a variant embodiment of the present invention. Various light-transmitting pattern designs can be applied to determine the light-transmitting effect of the second covering layer 304. In Figure 12A, the second covering layer 304 is a pattern having two or more parallel line groups aligned and intersecting with each other. In Figure 12B, the second covering layer 304 is composed of concentric circles or concentric ellipses. The width and density of the lines and line groups are adjustable to change the light transmittance of the second covering layer 304. As shown in Figure 12C, the second cover layer 304 is a pattern formed by integrating multiple dots. The shape and size of each dot, as well as the spacing between dots, can also be used to adjust the light transmittance of the second cover layer 304. Regardless of the transmittance, reflectivity, and absorptivity of the second cover layer 304, the second cover layer 304 at least partially blocks (reflects or absorbs) light from the light-emitting element 22 from transmitting to the corresponding upper opening 104 of the base plate 10, thereby reducing the light intensity of the corresponding inner light-transmitting portion 120 of the keycap 12.

Returning to FIG11 , the light-transmitting cover structure 30 can be configured to partially enter the opening 104 of the base plate 10 and partially remain below the bottom surface 102 of the base plate 10. The top glue 26 (26') and bottom glue 28 (28') shown in FIG4 and FIG5 (omitted in FIG11 ) can be applied to the top and bottom of the spacer 24 of FIG11 , respectively. Therefore, the total thickness of the spacer 24, the top glue 26 (26'), and the bottom glue 28 (28') is greater than or equal to the sum of the height of the light-emitting element 22 and the thickness of the first cover layer 302 of the light-transmitting cover structure 30 above the light-emitting element 22. In FIG11 , although the second cover layer 304 is higher than the bottom surface of the base plate 10 and enters the opening 104, it is still possible to lower the second cover layer 304 and the entire light-transmitting cover structure 30 by reducing the thickness of the light-transmitting cover structure 30 or increasing the thickness of at least one of the spacer 24, the top glue 26 (26'), and the bottom glue 28 (28') to maintain the same height as or below the bottom surface of the base plate 10. In this case, the total thickness of the spacer 24, the top glue 26 (26'), and the bottom glue 28 (28') is greater than or equal to the sum of the height of the light-emitting element 22 and the thickness of the light-transmitting cover structure 30 above the light-emitting element 22.

Please refer to Figure 13, which is a cross-sectional view of the light-emitting key structure 1 of another variant embodiment of the present invention. The second cover layer 304 may include a reflective layer that reflects light back to the first cover layer. Optionally, the second cover layer 304 may include two coating layers, such as an upper light-absorbing layer and a bottom reflective layer. If necessary, the diameter of the upper light-absorbing layer may be smaller than the diameter of the bottom reflective layer to allow a certain proportion of non-reflected light to pass through. The reflective second cover layer 304 better reflects light back to the first cover layer 302 to be reused to illuminate all inner light-transmitting portions 120 and the light-transmitting portions 120 in the corners. Referring to Figures 4 and 13 , the upper surface 244 of the spacer 24 may have an annular clear edge 244a surrounding the through-hole 242 of the spacer 24. The annular clear edge 244a is free of the top glue 26', which prevents the top glue 26' from overflowing into the through-hole 242 of the spacer 24 or the opening 104 of the base plate 10. Similarly, referring to Figures 5 and 13 , the lower surface 246 of the spacer 24 may have an annular clear edge 246a (omitted in Figure 13 ) surrounding the through-hole 242 of the spacer 24. The annular clear edge 246a is free of the bottom glue 28' to prevent the bottom glue 28' from entering the through-hole 242.

In Figures 1 and 13 , the base plate 10 includes ribs 106 that separate the four corner openings 104' from the inner openings 104. In some cases, we have found that the ribs 106 actually block light. The ribs 106 do not effectively reflect light downward like metal does, allowing it to reflect back into the interior of the illuminated key 1 a second time, resulting in a loss of illumination. Therefore, in some embodiments, the ribs 106 of the base plate 10 contribute little to the uniformity of illumination across the entire keycap 12 and can be further adjusted. In Figure 13 , three second cover layers 304 are shown. If the first cover layer 302 overlaps the vertical projections of at least two openings 104 or 104' and also overlaps the vertical projections of at least two ribs 106, this helps improve lighting uniformity. Each of the two transverse second cover layers 304 not only covers a portion of the first cover layer 302 but also shields the first cover layer 302 from the corresponding rib 106 of the base plate 10. Similarly, the two transverse second cover layers 304 can be reflective to reflect light back toward the first cover layer. Thus, light directed toward the ribs 106 can be reflected and recycled back into the first cover layer 302 for further reuse. Furthermore, in another derivative example, the second covering layer 304 below the ribs of the base plate 10 can be implemented by coating the second covering layer 304 on the bottom surface, rather than directly coating it on the top surface of the first covering layer 302.

Referring to FIG. 13 , light recycling is crucial for low-light emitting elements 22. To better recycle light reflected from the second cover layer 304 to the first cover layer 302, the driver circuit board 20 includes multiple reflectors 208 disposed on its top surface. These reflectors 208 correspond to the inner openings 104 and the corner openings 104' of the base plate 10. The first cover layer 302 covers these reflectors 208, meaning the reflectors 208 are located beneath the first cover layer 302. Consequently, the amount of light illuminating the corners of the keycap 12 through the light-transmitting portion 120 is increased, improving illumination uniformity across the entire keycap 12. In another embodiment, all of the multiple reflectors 208 in FIG. 13 are integrated into a single device to achieve better lateral light transmission performance. Alternatively, in addition to the multiple reflectors 208 in FIG. 13 , an additional larger bottom reflector 208 can surround the light-emitting element 22 and cover the top surface of the driver circuit board 20 within the through hole 242, with all of the smaller reflectors 208 disposed on the larger bottom reflector 208.

Refer to Figures 14 and 15 , which are exploded views and cross-sectional views, respectively, of another alternative embodiment of the light-emitting key structure 1. The primary difference between Figures 14 and 15 and the previous embodiment is that the through-hole 242 is primarily filled with air and not with other materials. The light-transmitting cover structure 30 here includes a flat first cover layer 302 and a second cover layer 304 disposed on the flat first cover layer 302. The flat first cover layer 302 is disposed between the base plate 10 and the spacer 24. Specifically, the flat first cover layer 302 covers the through-hole 242 of the spacer 24 and also covers the light-emitting element 22 within the through-hole 242. The flat first cover layer 302 does not extend into the through-hole 242 and also overlaps at least two of the openings 104 and 104' in the base plate 10. The flat first cover layer 302 can still be made of a light-transmitting material, while the second cover layer 304 at least partially blocks light to reduce the luminous intensity of a corresponding light-transmitting portion 120 in the keycap 12. The double-layer second cover layer 304 in Figure 13 also applies to Figure 15. Here, both the upper light-absorbing layer and the bottom reflective layer can be disposed on the flat first cover layer 302. Alternatively, only the upper light-absorbing layer can be disposed on the flat first cover layer 302, while the bottom reflective layer can be disposed below the flat first cover layer 302. One advantage of this embodiment is that Figures 14 and 15 are thin, transparent or translucent sheets, making it easier to print or coat the second covering layer 304 to a certain height during automated manufacturing. This is easier than forming the second covering layer 304 on a solidified, much smaller block of the first covering layer 302 (e.g., Figure 13).

Refer to Figure 16, which is a cross-sectional view of a light-emitting key structure 1 according to a variant embodiment of the present invention. Compared to Figure 13, in addition to a blocky first cover layer 302 and a plurality of reflective second cover layers 304, the light-transmitting cover structure 30 in Figure 16 further includes a planar first cover layer 306. The planar first cover layer 306 can be the same as the planar first cover layer 302 described in the embodiments related to Figures 14 and 15 above. The planar first cover layer 306 is disposed between the base plate 10 and the spacer 24. Specifically, the planar first cover layer 306 covers the through-hole 242 of the spacer 24 and the light-emitting element 22 in the through-hole 242. On top of the flat first cover layer 306, the flat first cover layer 306 includes a spacer adhesive 308 for bonding to the base plate 10. The top surface of the flat first cover layer 306 also has a circular clear edge 306a surrounding the bottom perimeter of all corner openings 104' in Figure 14. Furthermore, a plurality of reflective second cover layers 304 are disposed above the flat first cover layer 306 and between the flat first cover layer 306 and the base plate 10. Some of the plurality of reflective second cover layers 304 are configured to correspond to the aforementioned ribs 106. Furthermore, similar to FIG13 , to better recycle light reflected from the second cover layer 304 to the first cover layer 302, the driver circuit board 20 includes a plurality of point reflectors 208a and surface reflectors 208. These point reflectors 208a and surface reflectors 208 are disposed on the top surface of the driver circuit board 20 and are located corresponding to the openings 104 on the inner side and the openings 104′ in the corners of the base plate 10. These point reflectors 208a and surface reflectors 208 are covered by the block-shaped first cover layer 302, that is, located below the block-shaped first cover layer 302. Therefore, light reflected by the second cover layer 304 back to the blocky first cover layer 302 is directed toward the reflective element 208a corresponding to the opening 104' at the corner of the base plate. This reduces the illumination of the light-transmitting portion 120 on the inner side of the keycap 12, while increasing the illumination of the light-transmitting portion 120 at the corner of the keycap 12, thereby enhancing the uniformity of illumination across the entire keycap 12.

There are many ways to arrange the above-mentioned point reflectors 208a and surface reflectors 208. For example, a plurality of parallel reinforcing ribs can be aligned and intersected with each other to form diamond-shaped rib units and diamond-shaped recesses therein. These ribs can be formed by winding a metal mesh. Since the entire top surface of the driving circuit board 20 is made of a reflective material or includes a reflective coating thereon, the surfaces of the rib units and recesses are reflective. Additional high-reflectivity coating dots can be filled into specific groups of these recesses to reflect light directly upward. Even without additional coating dots, the rib units and recesses themselves are already microstructures that can directly reflect light. By flattening or coating the rest of the recess with a non-reflective material, the uneven or uncoated area of the recess and the surrounding ribs can be transformed into dedicated reflective portions for illuminating a particular light-transmitting portion 120.

Through the technical solutions of Figures 11, 12A, 12B, 12C, 13, 14, 15, and 16, the illumination uniformity of the entire keycap 12 of the illuminated key 1 equipped with a dedicated low-intensity light-emitting element 22 can be significantly improved. Furthermore, the illumination loss caused by light traveling toward the ribs 106 of the base plate 10 can be addressed by the corresponding reflective second cover layer 304. Furthermore, a larger block-shaped first cover layer 302 is introduced to cover the light-emitting element 22 within the through-hole 242 of the spacer 24. Its size is sufficient to overlap the vertical projections of at least two of the multiple openings 104/104' of the base plate 10. This blocky first cover layer 302 can have a reflector 208 underneath to reflect the recovered light toward the light-transmitting portion 120 at the corner of the keycap 12, improving illumination uniformity. A flat first cover layer 306 can also be used with or without the blocky first cover layer 302, thereby optimizing illumination uniformity of the illuminated key structure when using a low-intensity light-emitting element 22.

Referring to FIG. 17 , which is a cross-sectional view of a light-emitting key structure 1 according to another variation of the present invention, FIG. 17 differs from the aforementioned embodiment in that the through hole 242 is much smaller, corresponding to only a portion of the multiple openings of the base plate 10, for example, only corresponding to the opening 104, and the configuration of the covering structure 30' is different. As shown in FIG. 17 , the light-emitting key structure 1 includes a base plate 10, a key cap 12, a lifting mechanism 14, a switch circuit board 16, an elastic reset member 18, a drive circuit board 20, a light-emitting member 22, and a spacer 24, which are the same or similar to those previously described. For example, the key cap 12 is disposed above the base plate 10 and has a plurality of light-transmitting portions 120 (e.g., numbers, symbols, letters, text, graphics, or a combination thereof). A lifting mechanism 14 is connected between the base plate 10 and the keycap 12, supporting the keycap 12 in its upward and downward motion relative to the base plate 10. A switch circuit board 16 is disposed below the keycap 12, preferably above the base plate 10. The switch circuit board 16 includes a switch 162. A resilient reset member 18 is disposed between the keycap 12 and the base plate 10, corresponding to the switch 162. When the keycap 12 is pressed, the resilient reset member 18 triggers the switch 162. The driving circuit board 20, the light-emitting element 22, the spacer 24, and the covering structure 30' constitute an illumination module, which is used to illuminate the key formed by the base plate 10, the key cap 12, the lifting mechanism 14, the switch circuit board 16, and the elastic reset element 18.

Referring to Figures 17 and 18 , which are schematic plan views of the base plate 10 of the luminous key structure 1 of Figure 17 , the base plate 10 can be stamped from metal, such that the base plate 10 has a plurality of ribs 106 . The ribs 106 are connected to define a plurality of openings (e.g., the opening 104 and two or more peripheral openings 104 ′). In this embodiment, four peripheral openings 104 ′ are arranged around the opening 104, but the present invention is not limited thereto. In other embodiments, the opening 104 may be surrounded on one side by a larger peripheral opening 104' and on the other side by two smaller peripheral openings 104', or on both sides by two larger peripheral openings 104', or on each side by two or more smaller peripheral openings 104'. The opening 104 (or peripheral opening 104') preferably at least partially corresponds to one or more light-transmitting portions 120 of the keycap 12. In one embodiment, as shown in FIG. 22 , the opening 104 preferably corresponds to one of the light-transmitting portions 120, such as the light-transmitting portion 120b marked with a "/", while the peripheral opening 104' corresponds to another light-transmitting portion 120, such as the light-transmitting portion 120a marked with a "?". From another perspective, each light-transmitting portion 120 of the keycap 12 preferably at least partially overlaps with one of the openings 104 and 104' of the base plate 10.

Referring to Figures 17 and 19 , which are schematic plan views of the covering structure 30' of the luminous key structure 1 of Figure 17 , the covering structure 30' includes an island-shaped covering portion 30a'. The island-shaped covering portion 30a' covers the light-emitting element 22 and the through-hole 242 of the spacer 24. In this embodiment, the covering structure 30' may further include a frame-shaped covering portion 30b' surrounding the island-shaped covering portion 30a'. The island-shaped covering portion 30a' extends to connect opposite sides of the frame-shaped covering portion 30b' to define two light-transmissive portions 306b within the frame-shaped covering portion 30b'. For example, as shown in Figure 22, the frame-shaped covering portion 30b' surrounds the outline of the keycap 12. In other words, the frame-shaped covering portion 30b' is preferably disposed continuously along the outline of the keycap 12 without vertically overlapping with the peripheral opening 104' of the base plate 10, but this is not limited to this. The island-shaped covering portion 30a' preferably extends from opposite sides of the long sides of the two light-transmitting portions 306b to connect the frame-shaped covering portion 30b', so that the two light-transmitting portions 306b surround the light-emitting element 22 disposed in the through-hole 242 of the spacer 24.

In one embodiment, each of the two light-transmissive portions 306b preferably has two or more corners and three or more sides, such that each corner of the frame-shaped cover portion 30b' corresponds to one of the corners of the two light-transmissive portions 306b. For example, as shown in FIG19 , the upper left corner and lower left corner of the left light-transmissive portion 306b correspond to the upper left corner and lower left corner of the frame-shaped cover portion 30b' and the keycap 12, respectively. Similarly, the upper right corner and lower right corner of the right light-transmissive portion 306b correspond to the upper right corner and lower right corner of the frame-shaped cover portion 30b' and the keycap 12, respectively. This configuration improves the uniformity of illumination of the keycap outline. Furthermore, in one embodiment, the width of the island-shaped covering portion 30a' between the two light-transmitting portions 306b is preferably 1/5, 1/4, 1/3, or more of the length of the longest side of the light-transmitting portion 306b. This ensures better illumination uniformity in the center and corner light-transmitting portions of the keycap 12, as well as the outline of the keycap 12.

In another embodiment (not shown), the island-shaped covering portion 30a' may be an independent covering portion, not connected to other covering portions of the covering structure 30'. For example, the island-shaped covering portion 30a' may be disposed within the frame-shaped covering portion 30b' without being connected thereto, thereby forming an annular light-transmitting portion within the frame-shaped covering portion 30b'. Similarly, the annular light-transmitting portion may surround the light-emitting element 22. In yet another embodiment, depending on actual application, the island-shaped covering portion 30a' may extend to connect to one side of the frame-shaped covering portion 30b' to form an open-loop light-transmitting portion. In other words, the island-shaped covering portion 30a' may be in the form of a semi-island.

Referring to Figures 17 and 19 , in one embodiment, the cover structure 30' includes a first cover layer 302' and a second cover layer 304'. The first cover layer 302' is configured to substantially reflect light, while the second cover layer 304' is configured to substantially block light. At least one of the first cover layer 302' and the second cover layer 304' forms an island-shaped cover portion 30a', and the first cover layer 302' and the second cover layer 304' together form a frame-shaped cover portion 30b', but the present invention is not limited thereto. In another embodiment, the frame-shaped cover portion 30b' may be formed by at least one of the first cover layer 302' and the second cover layer 304'. The first cover layer 302' and the second cover layer 304' have different light transmittances. The first cover layer 302' reflects most light while allowing a small portion to pass through (or absorbing a small portion of light). The second cover layer 304' substantially blocks or absorbs most light while allowing a small portion to pass through (or reflecting a small portion of light). For example, in one embodiment, the first cover layer 302' can be a white ink layer, and the second cover layer 304' can be a black ink layer. Both can be formed using printing technology, but are not limited to this. Furthermore, the covering structure 30' further includes a flat covering layer 306'. The first covering layer 302' and the second covering layer 304' are disposed on the same side or opposite sides of the flat covering layer 306', and the first covering layer 302' is closer to the spacer 24 than the second covering layer 304'. For example, the flat covering layer 306' can be a light-transmissive film, such as a polyethylene terephthalate (PET) film, and the first covering layer 302' and the second covering layer 304' are disposed on or printed on the flat covering layer 306'. In one embodiment, the light-transmissive portion 306b is preferably the portion of the flat cover layer 306' where the first cover layer 302' and the second cover layer 304' are not disposed. In another embodiment, the light-transmissive portion 306b may be the portion (or opening) of the flat cover layer 306' where the first cover layer 302' and the second cover layer 304' are not disposed. In one embodiment, the second cover layer 304' is closer to the base plate 10 than the first cover layer 302' (i.e., the first cover layer 302' is closer to the spacer 24 than the second cover layer 304'). In this way, most of the upward light is first reflected by the first cover layer 302', while a small portion of the upward light passes through the first cover layer 302' and is then absorbed by the second cover layer 304', effectively guiding the upward light from the vertical (upward) direction to the horizontal (or horizontal) direction.

In one embodiment, as shown in FIG17 , the first cover layer 302′ and the second cover layer 304′ are preferably disposed on different surfaces of the planar cover layer 306′. For example, the first cover layer 302′ is disposed on the lower surface of the planar cover layer 306′ (i.e., closer to the spacers 24), while the second cover layer 304′ is disposed on the upper surface of the planar cover layer 306′ (i.e., closer to the base plate 10), but the present invention is not limited thereto. In another embodiment (not shown), the first cover layer 302′ and the second cover layer 304′ may be disposed on the same surface of the planar cover layer 306′. For example, the first cover layer 302' can be disposed on the upper surface of the flat cover layer 306', while the second cover layer 304' can be disposed on the upper surface of the flat cover layer 306' and/or the upper surface of the first cover layer 302'. Alternatively, the second cover layer 304' can be disposed on the lower surface of the flat cover layer 306', while the first cover layer 302' can be disposed on the lower surface of the flat cover layer 306' and/or the lower surface of the second cover layer 304'. In this way, most of the upward-directed light is reflected by the first cover layer 302', while a small amount passes through the first cover layer 302' and is absorbed by the second cover layer 304'.

Note that in the diagrams (e.g., Figure 19 or Figure 22), the left-hatched area indicates where the first cover layer 302' is located, while the vertically hatched area indicates where the second cover layer 304' is located. When both left-hatched and vertically hatched lines are present in an area, the area indicates where the first and second cover layers 302', 304' overlap, with the first cover layer 302' being closer to the spacer 24 than the second cover layer 304'.

Referring to Figure 17 , the second cover layer 304' preferably extends from the first cover layer 302' to at least partially surround at least one of the two light-transmissive portions 306b. Specifically, the island-shaped cover portion 30a' is positioned corresponding to the opening 104 of the base plate 10 and covers the light-emitting element 22. In the area between the two light-transmissive portions 306b, the width of the second cover layer 304' is preferably greater than that of the first cover layer 302'. For example, the first cover layer 302' preferably vertically overlaps the opening 104 and further extends to the rib 106, while the second cover layer 304' vertically overlaps the first cover layer 302' and further extends from the first cover layer 302' to partially overlap the peripheral opening 104'. As shown in Figure 19, the second cover layer 304' defines the edge of the light-transmissive portion 306b. In other words, the edge 3041 of the second cover layer 304' serves as the edge of the light-transmissive portion 306b. The area between the edge 3021 of the first cover layer 302′ and the edge 3041 of the second cover layer 304′ is where the second cover layer 304′ is located, but this is not limited to this. In other embodiments (not shown), the light-transmissive portion 306b may be defined by at least one of the first cover layer 302′ and the second cover layer 304′. For example, the first cover layer 302′ may extend from the second cover layer 304′ to surround the light-transmissive portion 306b. Alternatively, the first cover layer 302′ and the second cover layer 304′ may have the same pattern and together define the light-transmissive portion 306b.

Referring to Figures 17 and 20, which are planar schematic diagrams of the spacer 24 of the light-emitting key structure 1 of Figure 17, the spacer 24 can be a film-shaped or sheet-shaped body, which can be made of a suitable optical material, such as an optical polymer. The through hole 242 is preferably smaller than the opening 104 of the base plate 10, and the light-emitting element 22 can be located in the through hole 242. In one embodiment, the spacer 24 can be a light guide plate, and the light emitted by the light-emitting element 22 enters the spacer 24 from the side wall of the through hole 242. The flat covering layer 306' is preferably completely overlapped with the spacer 24, so that the island-shaped covering portion 30a' is located directly above the through hole 242. The spacer 24 is bonded between the covering structure 30' and the driving circuit board 20. Similar to the aforementioned embodiment, top adhesive 26 and bottom adhesive 28 are disposed on the upper surface 244 and lower surface 246 of the spacer 24, respectively, and are positioned around the through-hole 242. Specifically, top adhesive 26 is used to connect the cover structure 30' and the spacer 24, while bottom adhesive 28 is used to connect the spacer 24 and the driver circuit board 20 (or the reflector layer 208). Top adhesive 26 or bottom adhesive 28 can be an annular adhesive portion surrounding the through-hole 242 of the spacer 24 and positioned between the light-transmissive portions 306b. Top adhesive 26 or bottom adhesive 28 can be made of an optical material that is light-transmissive and has a refractive index closer to that of the spacer 24 than that of air. In this way, a relatively high proportion of the light reflected from the first cover layer 302' can enter the spacer 24 and then propagate through total internal reflection in the spacer 24.

Furthermore, the spacer 24 has one or more adhesive-free clear edges (e.g., 244a or 246a) that at least partially surround the through-hole 242. Specifically, the top adhesive 26 or bottom adhesive 28 is spaced a distance from the edge of the through-hole 242 of the spacer 24, forming an annular clear edge 244a or 246a therebetween. This is an area surrounding the through-hole 242 that is free of the top adhesive 26 or bottom adhesive 28. The spacer 24 may further have a diffusion pattern 24a comprising multiple light-emitting portions (e.g., microstructures or light-emitting points) to disrupt total internal reflection (TRI) of light and allow it to be emitted upward. The diffusion pattern 24a is preferably positioned corresponding to the peripheral opening 104' (or the light-transmissive portion 306b), but is not limited thereto. The diffusion pattern 24a can be positioned at any suitable light-emitting location. In one embodiment, the diffusion pattern 24a is positioned on the lower surface 246 of the spacer 24, but is not limited thereto.

Referring to Figures 17 and 21 , which are schematic plan views of the driver circuit board 20 of the light-emitting key structure 1 of Figure 17 , a reflective layer 208 is disposed on the driver circuit board 20, and the light-emitting element 22 is disposed on the driver circuit board 20 adjacent to the reflective layer 208. The reflective layer 208 is used to reflect light exposed from the lower surface 246 of the spacer 24 back toward the spacer 24. Specifically, the reflective layer 208 can be a reflective film made of a reflective material (e.g., metal foil), a reflective material layer coated on a non-reflective film, or a plastic film doped with reflective particles (e.g., a PET film doped with reflective particles), but is not limited thereto. In one embodiment, the reflective layer 208 can be a reflective coating (e.g., a white ink coating) applied to the top surface of the driver circuit board 20. The reflectivity of the reflective layer 208 is preferably greater than 80%, but is not limited thereto. The openings in the reflective layer 208 can be through-holes extending through the reflective layer 208, or can be portions of the top surface of the driver circuit board 20 where the light-emitting elements 22 are to be disposed and which are not coated with the reflective coating. The driver circuit board 20 further includes one or more main traces 211 and one or more sub- traces 212. For example, two main wirings 211 provide high and low potentials, respectively, and two sub-wirings 212 extend from the two main wirings 211, respectively, so that the light-emitting element 22 is electrically connected to the main wirings 211 via the sub-wirings 212. Furthermore, a light-absorbing layer (not shown) can be disposed beneath the reflective layer 208 to absorb light passing through the reflective layer 208.

Furthermore, as shown in Figure 17 , the reflective layer 208 may have a reflective pattern 208b, which may include a plurality of microstructures (e.g., reflective dots) disposed on the top surface of the reflective layer 208. The reflective pattern 208b may be positioned away from the light-emitting element 22 and serve to direct light upward. For example, the reflective pattern 208b may be positioned corresponding to the peripheral opening 104' (or the light-transmissive portion 306b), but this is not limited to such. The reflective pattern 208b may be positioned at any suitable light-emitting location. In one embodiment, the reflective pattern 208b is disposed on the top surface of the reflective layer 208, but this is not limited to such.

From another point of view, the illumination module of the light-emitting key structure 1 further includes a light-emitting pattern. The light-emitting pattern is actually arranged adjacent to the island-shaped covering portion 30a' and is used to guide light upward. The light-emitting pattern includes a reflective pattern 208b on the reflective layer 208 and a diffusion pattern 24a on the spacer 24. The light-emitting pattern is used to guide light upward to at least one of the two light-transmitting portions 306b, and then pass through at least one peripheral opening 104' of the base plate 10. When the microstructure or reflection point of the reflective pattern 208b is arranged to overlap with the light-emitting portion of the diffusion pattern 24a of the spacer 24 in the stacking direction (i.e., the vertical direction D1 of the aforementioned embodiment), the light output can be increased. When the microstructures or reflection points of the reflective pattern 208b are arranged so as not to overlap with the light-emitting portion of the diffusion pattern 24a of the spacer 24 in the stacking direction, light recovery can be enhanced.

Referring to Figures 17 and 22 , which are schematic plan views of certain components of the luminous key structure 1 of Figure 17 , each light-transmissive portion 306b preferably at least partially overlaps with the light-emitting pattern. Each light-transmissive portion 306b has two or more corners and three or more sides, such that each side of the keycap 12 corresponds to at least one of these sides of the two light-transmissive portions 306b. For example, the left and right sides of the keycap 12 correspond to the left side of the left light-transmissive portion 306b and the right side of the right light-transmissive portion 306b, respectively. The upper side of the keycap 12 corresponds to the upper sides of the two light-transmitting portions 306b, while the lower side of the keycap 12 corresponds to the lower sides of the two light-transmitting portions 306b.

In one embodiment, one of the two light-transmitting portions 306b is located between two of the plurality of light-transmitting portions 120. For example, the right-side light-transmitting portion 306b is located between light-transmitting portion 120a and light-transmitting portion 120b. In other words, the light-emitting pattern on the right side is located between light-transmitting portion 120a and light-transmitting portion 120b. In another embodiment, one of the two light-transmitting portions 120 is located between one of the plurality of light-transmitting portions 120 and the outline of the keycap 12. For example, the right-side light-transmitting portion 306b is located between light-transmitting portion 120b and the right edge of the keycap 12. In other words, the light-emitting pattern on the right side is located between light-transmitting portion 120b and the right edge of the keycap 12. In yet another embodiment, the light-transmissive portion 306b may be located below one of the light-transmissive portions 120. For example, the right light-transmissive portion (or the right light-emitting pattern) is located below the light-transmissive portion 120a. In one embodiment, when the keycap 12 is a square keycap, the difference between the distance between the light-transmissive portion 306b (or the light-emitting pattern) and the light-emitting element 22, and the distance between the light-transmissive portion 120a and the light-emitting element 22, is preferably less than 1/4 of the side length of the keycap 12. In another embodiment, when the keycap 12 is a square keycap, the distance between the light-transmissive portion 306b (or the light-emitting pattern) and the light-transmissive portion 120a is preferably less than 1/4 of the side length of the keycap 12. The aforementioned "distance" can be the distance between the light-transmitting portion 306b (or the light-emitting pattern) and the geometric center of the light-transmitting portion 120a, the average distance, the minimum distance, or the maximum distance.

Since the light emitting patterns are arranged corresponding to the two light-transmissive portions 306b, the two light emitting patterns are preferably arranged to surround the island-shaped covering portion 30a', for example, on two opposite sides. According to the configuration of the above embodiment, little or no light passes through the openings 104 of the base plate 10 to illuminate the light-transmitting portions 120b. Instead, light propagates laterally (or horizontally) within the spacer 24. When the light strikes the light-emitting pattern, it is emitted upward through the two light-transmitting portions 306b and subsequently through the peripheral openings 104' of the base plate 102. This allows the light-transmitting portions 120b above the island-shaped cover portion 30a' to be illuminated by the two light-transmitting portions 306b. Furthermore, the light-transmitting portions 120a near the corners or sides of the keycap 12 are also illuminated, improving the uniformity of illumination for the characters in the center and corners of the keycap 12.

Those skilled in the art will appreciate that other modifications of the exemplary embodiments specifically described herein may be made without departing from the spirit of the present invention. Therefore, the scope of the present invention also covers such modifications and is limited only by the scope of the appended patent applications.

12 Keycap 120a, 120b Translucent portions 208b Reflective pattern 22 Light-emitting element 242 Through-hole 24a Diffusion pattern 244a Annular clear edge 26 Top adhesive 30a Island-shaped covering portion 30b Frame-shaped covering portion 304 Second covering layer 306b Translucent portion

Claims (18)

An illumination module for illuminating a keypad comprises: a driver circuit board having a reflective layer disposed thereon; a light-emitting element disposed on the driver circuit board and adjacent to the reflective layer; a covering structure having an island-shaped covering portion; and a spacer bonded between the covering structure and the driver circuit board, the spacer having a through hole and a non-adhesive clear edge at least partially surrounding the through hole, wherein the island-shaped covering portion covers the light-emitting element and the through hole. The covering structure further includes a frame-shaped covering portion surrounding the island-shaped covering portion. The island-shaped covering portion extends to connect two opposite sides of the frame-shaped covering portion to define two light-transmissive portions in the frame-shaped covering portion. The two light-transmissive portions surround the light-emitting element. The illumination module as described in claim 1 further includes a light emitting pattern, wherein the light emitting pattern includes a reflection pattern and a diffusion pattern, the reflection pattern is on the reflection layer, the diffusion pattern is on the spacer, and the light emitting pattern is used to guide light upward to at least one of the two light-transmissive parts. The illumination module as described in claim 1, wherein the two light-transmitting parts each have two or more corners and three or more sides, so that each corner of the frame-shaped covering part corresponds to one of the corners of the two light-transmitting parts. An illumination module as described in claim 1, wherein the covering structure includes a first covering layer and a second covering layer, the first covering layer is used to substantially reflect light, and the second covering layer is used to substantially block light, at least one of the first covering layer and the second covering layer forms the island-shaped covering portion, and the first covering layer and the second covering layer together form the frame-shaped covering portion. The illumination module as described in claim 4, wherein the covering structure further includes a flat covering layer, the first covering layer and the second covering layer are arranged on the same side or two opposite sides of the flat covering layer, and the first covering layer is closer to the spacer than the second covering layer. The illumination module as described in claim 4, wherein the second covering layer extends from the first covering layer to at least partially surround at least one of the two light-transmissive portions. A light-emitting key structure comprises: a base plate having an opening; a key cap disposed relative to the base plate; and an illumination module comprising: a driver circuit board having a reflective layer disposed thereon; a light-emitting element disposed on the driver circuit board and adjacent to the reflective layer; a covering structure having a frame-shaped covering portion and an island-shaped covering portion; and a spacer bonded between the covering structure and the driver circuit board, the spacer having a through hole and a glue-free clear edge, the through hole corresponding to the opening, and the glue-free clear edge at least partially surrounding the through hole. The frame-shaped covering portion is disposed around the outline of the keycap, and the island-shaped covering portion covers the light-emitting element and the through-hole. The island-shaped covering portion extends to connect opposite sides of the frame-shaped covering portion to define two light-transmissive portions within the frame-shaped covering portion, and the two light-transmissive portions surround the light-emitting element. The luminous key structure as described in claim 7, wherein the two light-transmissive parts each have two or more corners and three or more sides, so that each corner of the keycap corresponds to one of the corners of the two light-transmissive parts. The luminous key structure as described in claim 7, wherein the two light-transmissive parts each have two or more corners and three or more side edges, and each side edge of the key cap corresponds to at least one of the side edges of the two light-transmissive parts. The luminous key structure as described in claim 7, wherein the base plate further has two or more peripheral openings arranged around the opening, and the two light-transmissive portions each at least partially correspond to at least one of the two or more peripheral openings. The light-emitting key structure as described in claim 10, wherein the illumination module further includes a light-emitting pattern, which corresponds to the two light-transmitting parts and is used to guide light upward through at least one of the two light-transmitting parts and further through the two or more peripheral openings. The light-emitting key structure as described in claim 11, wherein the light-emitting pattern includes a reflective pattern and a diffusion pattern, the reflective pattern is on the reflective layer, and the diffusion pattern is on the spacer. The luminous key structure as described in claim 7, wherein the key cap has multiple light-transmitting portions, and one of the two light-transmitting portions is located between two of the multiple light-transmitting portions. The luminous key structure as described in claim 7, wherein the key cap has multiple light-transmitting portions, and one of the two light-transmitting portions is located between one of the multiple light-transmitting portions and the outline of the key cap. The luminous key structure as described in claim 7, wherein the covering structure includes a first covering layer and a second covering layer, the first covering layer is used to substantially reflect light, the second covering layer is used to substantially block light, at least one of the first covering layer and the second covering layer forms the island-shaped covering portion, and the first covering layer and the second covering layer together form the frame-shaped covering portion. The light-emitting key structure as described in claim 15, wherein the second covering layer extends from the first covering layer to at least partially surround at least one of the two light-transmissive portions. An illumination module for illuminating a keypad comprises: a driver circuit board having a reflective layer disposed thereon; a light-emitting element disposed on the driver circuit board and adjacent to the reflective layer; a covering structure having an island-shaped covering portion; a spacer bonded between the covering structure and the driver circuit board, the spacer having a through hole and a glue-free clear edge at least partially surrounding the through hole; and a light-emitting pattern comprising a reflective pattern and a diffusion pattern, the reflective pattern being on the reflective layer and the diffusion pattern being on the spacer. The island-shaped covering portion covers the light-emitting element and the through hole, and the light-emitting pattern is substantially disposed adjacent to the island-shaped covering portion and configured to guide light upward. The covering structure further includes a frame-shaped covering portion surrounding the island-shaped covering portion. The island-shaped covering portion extends to connect two opposite sides of the frame-shaped covering portion to define two light-transmissive portions in the frame-shaped covering portion. The two light-transmissive portions surround the light-emitting element. The illumination module as described in claim 17, wherein the light-emitting pattern is used to guide the light upward to at least one of the two light-transmissive parts.