TWI852409B - Backlight keyswitch and backlight module thereof - Google Patents

Abstract

A backlight keyswitch includes a keyswitch body, a board connected to the keyswitch body, a backlight module and a membrane disposed between the keyswitch body and the board. The backlight module is disposed under the board and includes a backlight circuit board, a light-blocking sheet, a first reflecting ink layer, and a light guide plate disposed between the light-blocking sheet and the backlight circuit board having a backlight source disposed in a containing hole of the light guide plate. The first reflecting ink layer is formed on the board, the membrane, or the light-blocking sheet and located above the backlight source, for at least partially reflecting light emitted by the backlight source back to an optical microstructure in the light guide plate, such that light can pass through the light-blocking sheet, the board and the membrane sequentially via scattering of the optical microstructure to be incident to the keyswitch body.

Description

Backlit keys and their backlight modules

The present invention relates to a backlight key and its backlight module, and in particular to a backlight key and its backlight module which use a reflective ink layer to reflect at least part of the light emitted upward by a backlight source back into a light guide plate.

Generally speaking, the backlight module of a backlight keyboard includes a light guide plate and a backlight light source. The bottom plate of the backlight keyboard is placed on the light guide plate and has perforated areas corresponding to the positions of the multiple backlight keys of the backlight keyboard. The light guide plate has an optical microstructure formed at the position corresponding to each perforated area to guide light rays through the perforated area to be incident on the corresponding characters on the backlight keys to produce a character luminous effect.

The common backlight source design at present is to directly configure a backlight circuit board with multiple LEDs corresponding to each key under the base plate, so that the LEDs can emit light to the corresponding characters on the keycaps to produce a character lighting effect. However, since the light emitted upward by the LEDs will directly enter the backlight keys, it often causes the middle characters on the backlight keys to be too bright but the side characters to be insufficiently bright, thus affecting the lighting uniformity of the backlight keys and the visual aesthetics when in use.

Therefore, the purpose of the present invention is to provide a backlight key and a backlight module thereof that use a reflective ink layer to reflect at least part of the light emitted upward from a backlight source back into a light guide plate, so as to solve the above-mentioned problem.

According to an embodiment, the backlight key of the present invention comprises a key body, a bottom plate, a thin film circuit board, and a backlight module. The bottom plate is arranged under the key body and connected to the key body so that the key body can move up and down relative to the bottom plate, and the bottom plate has at least one perforated area at a position corresponding to the key body. The thin film circuit board is arranged between the key body and the bottom plate. The backlight module is arranged under the bottom plate, and the backlight module comprises a light guide plate, a backlight circuit board, a light shielding sheet, and a first reflective ink layer. The light guide plate has a receiving hole at a position corresponding to the key body, and an optical microstructure is formed at a position corresponding to the at least one perforated area. The backlight circuit board is arranged under the light guide plate and has a backlight source, and the backlight source is arranged in the receiving hole. The light shielding sheet is arranged between the bottom plate and the light guide plate and has a light-transmitting area corresponding to the position of the key body. The first reflective ink layer is formed on one of the bottom plate, the thin film circuit board and the light shielding sheet and is located above the backlight source, and is used to reflect at least part of the light emitted upward by the backlight source back to the optical microstructure and pass through the light-transmitting area, the at least one perforated area and the thin film circuit board in sequence through the scattering of the optical microstructure to be incident on the key body.

According to another embodiment, the backlight module of the present invention is applicable to a backlight key, the backlight key has a key body, a bottom plate, and a thin film circuit board, the bottom plate is arranged under the key body and connected to the key body so that the key body can move up and down relative to the bottom plate, the bottom plate has at least one perforated area at a position corresponding to the key body, the thin film circuit board is arranged between the key body and the bottom plate, the backlight module includes a light guide plate, a backlight circuit board, a light shielding sheet, and a first reflective ink layer. The light guide plate has a receiving hole at a position corresponding to the key body and an optical microstructure is formed at a position corresponding to the at least one perforated area. The backlight circuit board is arranged under the light guide plate and has a backlight source, and the backlight source is arranged in the receiving hole. The light shielding sheet is arranged between the bottom plate and the light guide plate and has a light-transmitting area corresponding to the position of the key body. The first reflective ink layer is formed on one of the bottom plate, the thin film circuit board and the light shielding sheet and is located above the backlight source, and is used to reflect at least part of the light emitted upward by the backlight source back to the optical microstructure and pass through the light-transmitting area, the at least one perforated area and the thin film circuit board in sequence through the scattering of the optical microstructure to be incident on the key body.

In summary, the present invention adopts a light guide design that sets a reflective ink layer above the backlight source to reflect at least part of the light emitted upward by the backlight source back to the light guide plate (to prevent the middle character from being too bright) and then scatters the light through the optical microstructure of the light guide plate to the key body (to improve the brightness of the side characters), so as to solve the problem mentioned in the prior art that the light emitted upward by the LED directly enters the backlight key, causing the middle character to be too bright but the side characters to be insufficiently bright, thereby greatly improving the light uniformity of the backlight key and the visual aesthetic effect when in use.

The advantages and spirit of the present invention can be further understood through the following detailed description of the invention and the attached drawings.

10, 100, 150, 200: Backlit buttons

12: Button body

14: Base plate

15: Hole area

16: Thin film circuit board

18, 102, 152, 202: Backlight module

20: Keycaps

22: Lifting mechanism

24: Elastic return piece

26: Light guide plate

28: Backlight circuit board

30: Shading film

31: Translucent area

32, 104, 156, 206: first reflective ink layer

34: Accommodation hole

36: Optical microstructures

38: Backlight source

40, 44: opaque ink layer

42: Second reflective ink layer

154, 204: Middle hole area

207: Filling hole

S1, S3, S4: lower surface

S2: Upper surface

Figure 1 is a simplified cross-sectional view of a backlight key according to one embodiment of the present invention.

Figure 2 is a diagram of different ink layer configurations proposed according to different embodiments of the present invention.

Figure 3 is a simplified cross-sectional view of a backlight key according to another embodiment of the present invention.

Figure 4 is a simplified cross-sectional view of a backlight key according to another embodiment of the present invention.

Figure 5 is a simplified cross-sectional view of a backlight key according to another embodiment of the present invention.

Figure 6 is a top perspective view showing the arrangement relationship between the key cap, base plate, first reflective ink layer and opaque ink layer in Figure 5.

The following content will be accompanied by drawings to illustrate the technical content of the present invention through specific concrete embodiments. People familiar with this technology can easily understand other advantages and effects of the present invention from the content disclosed in this manual. The present invention can also be implemented or applied through other different specific embodiments. The details in this manual can also be modified and changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. In particular, the proportions and configurations of the various components in the drawings (such as the proportions of the ink layer, etc.) are only for exemplary purposes and do not represent the actual implementation of the present invention.

Please refer to FIG. 1, which is a cross-sectional view of a backlight key 10 according to an embodiment of the present invention. The backlight key 10 can be preferably applied to an openable electronic device generally composed of an upper cover and a lower housing or an electronic device having a key input function (such as a notebook computer or a keyboard device, but not limited thereto) and provides a character luminous function so that the user can press to execute the function the user wants to input. As shown in FIG. 1, the backlight key 10 includes a key body 12, a bottom plate 14, a thin film circuit board 16, and a backlight module 18. The bottom plate 14 is disposed under the key body 12 and connected to the key body 12 so that the key body 12 can move up and down relative to the bottom plate 14. The bottom plate 14 has at least one hole area 15 (two are shown in FIG. 1, but not limited thereto) at a position corresponding to the key body 12, and the thin film circuit board 16 is disposed between the key body 12 and the bottom plate 14. As for the description of the components of the key body 12, it is common in the prior art, for example, Specifically, the key body 12 may include a key cap 20, a lifting mechanism 22, and an elastic reset member 24 (but not limited thereto), the thin film circuit board 16 has a switch, the key cap 20 is connected to the lifting mechanism 22, the lifting mechanism 22 may be movably disposed on the bottom plate 14 to support the key cap 20 to move up and down to approach or move away from the switch, and the elastic restoring force stored in the elastic reset member 24 when it is pressed may help the key cap 20 return to its initial position so that the user can perform subsequent pressing operations.

The following is a detailed description of the design of the backlight module 18 . The backlight module 18 is disposed under the base plate 14 and includes a light guide plate 26 , a backlight circuit board 28 , a light shielding sheet 30 , and a first reflective ink layer 32 . The light guide plate 26 has a receiving hole 34 at a position corresponding to the key body 12 and an optical microstructure 36 is formed at a position corresponding to the perforated area 15. The backlight circuit board 28 is disposed under the light guide plate 26 and has a backlight source 38. The backlight source 38 (preferably a light-emitting diode, but not limited thereto) is disposed in the receiving hole 34. The light shielding sheet 30 is disposed between the bottom plate 14 and the light guide plate 26 and has a light-transmitting area 31 at a position corresponding to the key body 12. The first reflective ink layer 32 is preferably a white ink layer (but not limited thereto) and is formed on the light shielding sheet 30 and is located above the backlight source 38. In more detail, in this embodiment, as shown in FIG. 1, the first reflective ink layer 32 can be formed on the lower surface S1 of the light shielding film 30, and in actual application, in order to prevent light from partially penetrating the first reflective ink layer 32 and directly incident on the key body 12 to further improve the problem of the middle character being too bright, the backlight module 18 can further include an opaque ink layer 40, which can be preferably a black ink layer (but not limited to this) and is formed on the upper surface S2 of the light shielding film 30 to prevent light penetrating the first reflective ink layer 32 from directly incident on the key body 12.

Through the above configuration, the first reflective ink layer 32 can reflect at least part of the light emitted upward by the backlight source 38 back into the light guide plate 26 and incident on the optical microstructure 36 (as shown in Figure 1). Thus, the light in the light guide plate 26 can be scattered by the optical microstructure 36 and sequentially pass through the light-transmitting area 31 of the light-shielding sheet 30, the perforated area 15 of the bottom plate 14 and the thin film circuit board 16 and incident on the key body 12, thereby producing a character luminous effect.

It should be noted that the configuration of the above-mentioned reflective ink layer and opaque ink layer can also be applied to the backlight circuit board 28. For example, as shown in FIG. 1, the backlight module 18 can further include a second reflective ink layer 42 and an opaque ink layer 44. The second reflective ink layer 42 (preferably a white ink layer, but not limited to this) is formed on the backlight circuit board 28 to reflect the light emitted downward from the light guide plate 26 back to the light guide plate 26, and the opaque ink layer 44 (preferably a black ink layer, but not limited to this) is formed under the backlight circuit board 28 to prevent light from penetrating the backlight circuit board 28, thereby further improving the light utilization efficiency of the backlight light source 38 incident on the light guide plate 26.

In summary, the present invention adopts a light guide design that sets a reflective ink layer above the backlight source to reflect at least part of the light emitted upward by the backlight source back to the light guide plate (to prevent the middle character from being too bright) and then scatters the light through the optical microstructure of the light guide plate to the key body (to improve the brightness of the side characters), so as to solve the problem mentioned in the prior art that the light emitted upward by the LED directly enters the backlight key, causing the middle character to be too bright but the side characters to be insufficiently bright, thereby greatly improving the light uniformity of the backlight key and the visual aesthetic effect when in use.

It is worth mentioning that the stacking configuration of the ink layer is not limited to the above-mentioned embodiment, that is, the present invention can also adopt other ink layer stacking designs, and the ink layer size ratio relationship and the ink color and type vary depending on the actual light output application of the backlight module 18. For example, as shown in Figure 2 (a), the first reflective ink layer 32 can be formed on the lower surface S1 of the light shielding film 30, and the opaque ink layer 40 can be formed between the first reflective ink layer 32 and the light shielding film 30; as shown in Figure 2 (b), the first reflective ink layer 32 can be formed on the upper surface S2 of the light shielding film 30, and the opaque ink layer 40 can be stacked on the first reflective ink layer 32.

In addition, the formation position of the reflective ink layer is not limited to the above-mentioned embodiment. For example, please refer to FIG. 3, which is a cross-sectional diagram of a backlight key 100 according to another embodiment of the present invention. The components in this embodiment and the above-mentioned embodiment have the same number, which represent the same or similar structure and function, and will not be repeated here. As shown in FIG. 3, the backlight key 100 includes a key body 12, a bottom plate 14, a thin film circuit board 16, and a backlight module 102. The backlight module 102 is arranged under the bottom plate 14 and includes a light guide plate 26, a backlight circuit board 28, a light shielding sheet 30, a second reflective ink layer 42, an opaque ink layer 44, and a first reflective ink layer 104. In this embodiment, the first reflective ink layer 104 is preferably a white ink layer (but not limited thereto) and is formed on the lower surface S3 of the bottom plate 14. Thus, as shown in FIG. 3, the first reflective ink layer 104 can reflect at least part of the light emitted upward by the backlight source 38 back into the light guide plate 26 and incident on the optical microstructure 36. In this way, the light in the light guide plate 26 can be scattered by the optical microstructure 36 and sequentially pass through the light-transmitting area 31 of the light-shielding sheet 30, the perforated area 15 of the bottom plate 14 and the thin film circuit board 16 and incident on the key body 12, thereby generating a character luminous effect.

In addition, please refer to FIG. 4, which is a cross-sectional diagram of a backlight key 150 according to another embodiment of the present invention. In this embodiment, the components mentioned in the above embodiment have the same number, which means that they have the same or similar structure and function, and will not be repeated here. As shown in FIG. 4, the backlight key 150 includes a key body 12, a bottom plate 14, a thin film circuit board 16, and a backlight module 152. The bottom plate 14 may also have a middle hole area 154. The backlight module 152 is arranged under the bottom plate 14 and includes a light guide plate 26, a backlight circuit board 28, a light shielding sheet 30, a second reflective ink layer 42, an opaque ink layer 44, and a first reflective ink layer 156. In this embodiment, the first reflective ink layer 156 is preferably a white ink layer (but not limited thereto) and is formed on the lower surface S4 of the thin film circuit board 16. Thus, as shown in FIG. 4, the first reflective ink layer 156 can reflect at least part of the light emitted upward by the backlight source 38 and passing through the middle hole area 154 back to the light guide plate 26 and incident on the optical microstructure 36. In this way, the light in the light guide plate 26 can be scattered by the optical microstructure 36 and sequentially pass through the light-transmitting area 31 of the light-shielding sheet 30, the perforated area 15 of the bottom plate 14 and the thin film circuit board 16 and incident on the key body 12, thereby generating a character luminous effect.

In actual application, in order to avoid the problem of insufficient brightness at the position of the key cap corresponding to the reflective ink layer, the present invention can also selectively adopt a fill light hole design. For example, please refer to Figure 5, which is a cross-sectional schematic diagram of a backlight key 200 proposed according to another embodiment of the present invention. In this embodiment, the components mentioned in the above embodiment have the same number, which represents the same or similar structure and function, and will not be repeated here. As shown in Figure 5, the backlight key 200 includes a key body 12, a base plate 14, a thin film circuit board 16, and a backlight module 202. The base plate 14 may further have a middle hole area 204. The backlight module 202 is arranged under the base plate 14 and includes a light guide plate 26, a backlight circuit board 28, a shading film 30, an opaque ink layer 40, a second reflective ink layer 42, an opaque ink layer 44, and a first reflective ink layer 206. In this embodiment, the first reflective ink layer 206 is preferably a white ink layer (but not limited thereto). The first reflective ink layer 206 can be formed on the upper surface S2 of the light shielding sheet 30 and has at least one light filling hole 207. FIG. 5 shows two light filling holes 207 respectively located on both sides of the opaque ink layer 40 (but not limited thereto). In addition to reflecting at least part of the light emitted upward by the backlight source 38 back to the light guide plate 26, the first reflective ink layer 206 can also allow the light emitted upward by the backlight source 38 to pass through the light filling hole 207, the middle hole area 204 and the thin film circuit board 16 and be incident on the key body 12 to produce a brightness compensation effect, thereby further improving the light uniformity of the backlight key 200.

In addition, please refer to Figures 5 and 6. Figure 6 is a top perspective view of the arrangement relationship between the key cap 20, the bottom plate 14, the first reflective ink layer 206 and the opaque ink layer 40 in Figure 5. It can be seen from Figures 5 and 6 that the first reflective ink layer 206 can be further formed on the position of the light shielding sheet 30 corresponding to the area of the bottom plate 14 other than the perforated area 15, so as to further improve the light utilization efficiency of the backlight source 38 incident on the light guide plate 26. The coating arrangement of the first reflective ink layer 206 shown in Figure 6 is only for example, and the present invention is not limited thereto.

The above is only the preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

10: Backlit buttons

12: Button body

14: Base plate

15: Hole area

16: Thin film circuit board

18: Backlight module

20: Keycaps

22: Lifting mechanism

24: Elastic return piece

26: Light guide plate

28: Backlight circuit board

30: Shading film

31: Translucent area

32: First reflective ink layer

34: Accommodation hole

36: Optical microstructures

38: Backlight source

40, 44: opaque ink layer

42: Second reflective ink layer

S1: Lower surface

S2: Upper surface

Claims (16)

A backlight key, comprising: a key body; a bottom plate, which is arranged under the key body and connected to the key body so that the key body can move up and down relative to the bottom plate, the bottom plate has at least one perforated area at a position corresponding to the key body, and the bottom plate also has a middle hole area; a thin film circuit board, which is arranged between the key body and the bottom plate; and a backlight module, which is arranged under the bottom plate, the backlight module comprising: a light guide A plate having a receiving hole at a position corresponding to the key body and an optical microstructure formed at a position corresponding to the at least one hole area; a backlight circuit board arranged under the light guide plate and having a backlight source, the backlight source being arranged in the receiving hole; a light shielding sheet arranged between the bottom plate and the light guide plate and having a light-transmitting area at a position corresponding to the key body; a first reflective ink layer formed on the light shielding sheet and located between the backlight source The first reflective ink layer has at least one light-filling hole; and an opaque ink layer, wherein the first reflective ink layer is formed on an upper surface of the shading sheet and the opaque ink layer is stacked on the first reflective ink layer. The ink layer is formed on the upper surface and the lower surface of the light shielding film, or the opaque ink layer and the first reflective ink layer are formed on the upper surface and the lower surface of the light shielding film respectively, so as to prevent the light penetrating the first reflective ink layer from being incident on the key body; the at least one fill-in hole is located on at least one side of the opaque ink layer, so that the light emitted upward by the backlight source can pass through the at least one fill-in hole, the middle hole area and the thin film circuit board and be incident on the key body. The backlit key as described in claim 1, wherein the first reflective ink layer is a white ink layer and the opaque ink layer is a black ink layer. The backlit key as described in claim 1, wherein the first reflective ink layer is formed on the area of the light shielding sheet corresponding to the bottom plate except for the at least one perforated area. A backlit key as described in claim 1, wherein the first reflective ink layer is a white ink layer. The backlight key as described in claim 1, wherein the backlight module further comprises: a second reflective ink layer formed on the backlight circuit board, which is used to reflect the light emitted downward from the light guide plate back to the light guide plate. The backlit key as described in claim 5, wherein the first reflective ink layer and the second reflective ink layer are white ink layers. The backlight key as described in claim 1, wherein the backlight module further comprises another opaque ink layer; the other opaque ink layer is formed under the backlight circuit board to prevent light from penetrating the backlight circuit board. A backlight module is applicable to a backlight key. The backlight key has a key body, a bottom plate, and a thin film circuit board. The bottom plate is arranged under the key body and connected to the key body so that the key body can move up and down relative to the bottom plate. The bottom plate has at least one perforated area at a position corresponding to the key body. The bottom plate also has a middle hole area. The thin film circuit board is arranged between the key body and the bottom plate. The backlight module includes The invention comprises: a light guide plate, which has a receiving hole at a position corresponding to the key body and an optical microstructure formed at a position corresponding to the at least one hole area; a backlight circuit board, which is arranged under the light guide plate and has a backlight light source, and the backlight light source is arranged in the receiving hole; a light shielding sheet, which is arranged between the bottom plate and the light guide plate and has a light-transmitting area at a position corresponding to the key body; a first reflective ink layer, which is formed on the light shielding sheet and is located at the back The backlight source is disposed above the backlight source to reflect at least part of the light emitted upward by the backlight source back to the optical microstructure and pass through the light-transmitting area, the at least one perforated area and the thin film circuit board in sequence through the scattering of the optical microstructure to be incident on the key body, the first reflective ink layer having at least one light-filling hole; and an opaque ink layer, wherein the first reflective ink layer is formed on an upper surface of the shading sheet and the opaque ink layer is stacked on the first The reflective ink layer, or the opaque ink layer and the first reflective ink layer are respectively formed on the upper surface and the lower surface of the light shielding film to prevent the light penetrating the first reflective ink layer from being incident on the key body; the at least one fill-in hole is located on at least one side of the opaque ink layer, so that the light emitted upward by the backlight source can pass through the at least one fill-in hole, the middle hole area and the thin film circuit board and be incident on the key body. The backlight module as described in claim 8, wherein the first reflective ink layer is a white ink layer, and the opaque ink layer is a black ink layer. The backlight module as described in claim 8, wherein the first reflective ink layer is formed on the area of the light shielding film corresponding to the bottom plate except for the at least one perforated area. The backlight module as described in claim 8, wherein the first reflective ink layer is a white ink layer. The backlight module as described in claim 8, wherein the backlight module further comprises: a second reflective ink layer formed on the backlight circuit board, which is used to reflect the light emitted downward from the light guide plate back to the light guide plate. The backlight module as described in claim 12, wherein the first reflective ink layer and the second reflective ink layer are white ink layers. A backlight module as described in claim 8, wherein the backlight module further comprises another opaque ink layer; the other opaque ink layer is formed under the backlight circuit board to prevent light from penetrating the backlight circuit board. A backlight key, comprising: a key body; a bottom plate, which is arranged under the key body and connected to the key body so that the key body can move up and down relative to the bottom plate, and the bottom plate has at least one hole area at a position corresponding to the key body; a thin film circuit board, which is arranged between the key body and the bottom plate; and a backlight module, which is arranged under the bottom plate, and the backlight module comprises: a light guide plate, which has a receiving hole at a position corresponding to the key body and an optical microstructure is formed at a position corresponding to the at least one hole area; a backlight circuit board, which is arranged between the light guide plate and the bottom plate. The backlight source is disposed under the plate and is arranged in the receiving hole; a light shielding sheet is arranged between the bottom plate and the light guide plate and has a light-transmitting area at a position corresponding to the key body; and a first reflective ink layer is formed at a position of the light shielding sheet corresponding to an area of the bottom plate except the at least one perforated area and is located above the backlight source, and is used to reflect at least part of the light emitted upward by the backlight source back to the optical microstructure and pass through the light-transmitting area, the at least one perforated area and the thin film circuit board in sequence through the scattering of the optical microstructure to be incident on the key body. A backlight module is applicable to a backlight key. The backlight key has a key body, a bottom plate, and a thin film circuit board. The bottom plate is arranged under the key body and connected to the key body so that the key body can move up and down relative to the bottom plate. The bottom plate has at least one perforated area at a position corresponding to the key body. The thin film circuit board is arranged between the key body and the bottom plate. The backlight module includes: a light guide plate having a receiving hole at a position corresponding to the key body and an optical microstructure formed at a position corresponding to the at least one perforated area; a backlight circuit board arranged between the light guide plate and the bottom plate. The backlight source is disposed under the optical plate and is disposed in the receiving hole; a light shielding sheet is disposed between the bottom plate and the light guide plate and has a light-transmitting area at a position corresponding to the key body; and a first reflective ink layer is formed at a position of the light shielding sheet corresponding to an area of the bottom plate other than the at least one perforated area and is located above the backlight source, and is used to reflect at least part of the light emitted upward by the backlight source back to the optical microstructure and pass through the light-transmitting area, the at least one perforated area and the thin film circuit board in sequence through the scattering of the optical microstructure to be incident on the key body.

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