CN114256017A - Backlight module and luminous keyboard - Google Patents

Abstract

The invention discloses a backlight module and a luminous keyboard. The light-emitting keyboard comprises a plurality of keys and a backlight module arranged below the keys, wherein one of the keys is a different-color key. The backlight module comprises a light guide plate, at least one multicolor light source group, a light attenuation structure and a second optical medium. The light guide plate is composed of a first optical medium; the multi-color light source group is provided with a plurality of multi-color light sources, wherein the first light source is closest to the different-color key; the second optical medium has a refractive index less than the refractive index of the first optical medium. The multicolor light source group is arranged corresponding to the light incident surface of the light guide plate. The second optical medium is arranged between the multicolor light source group and the light incident surface. The light attenuation structure is arranged between the first light source and the heterochromatic keys and attenuates first chromatic light of the first light source passing through or passing through the light attenuation structure. The invention can effectively solve the problem of color difference that the luminous color of the key is biased to the color of the colored light of the light source closest to the key, thereby greatly improving the luminous effect and the use impression of the key of the luminous keyboard.

Description

Backlight module and luminous keyboard

Technical Field

The present invention relates to a backlight module and a light-emitting keyboard thereof, and more particularly, to a backlight module and a light-emitting keyboard thereof using a light attenuating structure to improve the problem of color shift of light emitted from keys.

Background

Generally, in order to make the keyboard have the key light emitting function, a backlight module having light emitting diodes is directly disposed under a plurality of keys of the keyboard, and light of the light emitting diodes can be incident on a light guide plate of the backlight module and finally emitted to a keycap of each key to generate the key light emitting effect.

In the prior art, the color light emitting effect on the keyboard is a light mixing design using a plurality of multi-color light source sets (such as red, green, and blue light emitting diodes (RGB LEDs)) to make the light emitting color of the identification mark on the keycap or the periphery of the keycap meet the requirement. The multiple groups of multi-color light source groups are usually arranged on a certain side or middle section of the keyboard, and the number, the angle and the distribution of the groups need to ensure that each key on the keyboard has high uniformity.

However, no matter where the multi-color light source group is arranged, the distance from each monochromatic light source to the light emitting position of each key is different, so that the specific key is affected by more closest monochromatic light sources to cause light mixing proportion deviation, and the light emitting colors of the specific key and surrounding keys are different, namely the problem of the so-called heterochromatic key is caused.

The light emitting color of the different color key is biased to the color of the color light emitted by the closest monochromatic light source. For example, when the entire keyboard is to emit white light uniformly, if the light source closest to the different-color key is the red light source of the multi-color light source group, the white light appearing on the different-color key is prone to have mixed light deviation of red, which affects the visual effect of the light-emitting keyboard and raises quality doubt.

Disclosure of Invention

In view of the problems in the prior art, the present invention provides a backlight module and a light-emitting keyboard to solve the above problems.

Therefore, an object of the present invention is to provide a backlight module, disposed under a plurality of keys of a light-emitting keyboard, wherein one of the keys is a different-color key, and a light-emitting area is defined by a keycap of the different-color key, the backlight module includes:

the light guide plate is provided with a bottom surface, a light incident surface and a light emergent surface, wherein the bottom surface is adjacent to the light incident surface and is opposite to the light emergent surface;

at least one multicolor light source group which is arranged corresponding to the light inlet surface of the light guide plate and comprises a plurality of light sources, the plurality of light sources generate a plurality of color lights which are different from each other, a first light source in the plurality of light sources is positioned at a first side of the multicolor light source group and is closest to the light outlet area of the different-color key, and a second light source in the plurality of light sources is positioned at a second side of the multicolor light source group and is farthest from the light outlet area of the different-color key;

at least one second optical medium arranged between the multi-color light source group and the light incident surface of the light guide plate, wherein the first refractive index of the first optical medium is greater than the second refractive index of the at least one second optical medium; and

the light attenuation structure is arranged between the first light source and the heterochromatic key and attenuates first chromatic light of the first light source passing through the light attenuation structure;

the first color light enters the light guide plate through the light incident surface, and the first color light sequentially passes through the second optical medium, the light attenuation structure and the light guide plate, so that the attenuated first color light and other color lights generated by the multi-color light source set generate mixed light, and the mixed light is emitted from the light emitting surface of the light guide plate to illuminate the light emitting area of the different-color key.

As an optional technical solution, the light incident surface of the light guide plate has a first light incident section and a second light incident section, the first light incident section is close to the first light source, the second light incident section is close to the second light source, and a second distance from the second light source to the second light incident section is smaller than a first distance from the first light source to the first light incident section.

As an optional technical solution, the light attenuating structure is disposed between the second optical medium and the first light incident section of the light incident surface, and the light attenuating structure is composed of a third medium, where the third medium has a third refractive index, and the third refractive index is not less than the second refractive index of the second medium.

As an optional technical solution, the light attenuating structure is an optical microstructure, and the optical microstructure is formed on the light emitting surface or the bottom surface and is adjacent to the light incident surface.

As an optional technical solution, the backlight module further includes a light shielding sheet, the light shielding sheet has a covering layer, the light shielding sheet is disposed on the light emitting surface, and the covering layer defines a plurality of openings respectively corresponding to the plurality of keys; the light attenuation structure is a semi-transparent adhesive layer, the adhesive layer is adhered between the shading sheet and the light guide plate, the adhesive layer corresponds to the light incident surface and the first light source, and the adhesive layer does not extend to correspond to the second light source.

As an optional technical solution, the backlight module further comprises a reflective sheet disposed under the bottom surface; the light attenuation structure is a semi-transparent adhesive layer, the adhesive layer is adhered between the reflector plate and the light guide plate, the adhesive layer corresponds to the light incident surface and the first light source, and the adhesive layer does not extend to correspond to the second light source.

As an optional technical solution, the backlight module further comprises a reflective sheet disposed under the bottom surface; the light attenuation structure is a semi-transparent adhesive layer, the adhesive layer is adhered between the reflection sheet and the light guide plate and corresponds to the light incident surface and the first light source, and the adhesive layer is provided with an extension section extending along a light transmission path of the first color light of the first light source.

As an optional technical solution, the backlight module further includes a light shielding sheet, the light shielding sheet has a covering layer, the light shielding sheet is disposed on the light emitting surface, and the covering layer defines a plurality of openings respectively corresponding to the plurality of keys; the light attenuation structure is a semi-transparent adhesive layer, the adhesive layer is adhered between the shading sheet and the light guide plate, the adhesive layer corresponds to the light incident surface and the first light source, and the adhesive layer is provided with an extension section which extends along the light transmission direction of the first color light of the first light source.

As an optional technical solution, the backlight module further includes a light shielding sheet, the light shielding sheet has a covering layer, the light shielding sheet is disposed on the light emitting surface, and the covering layer defines a plurality of openings respectively corresponding to the plurality of keys; the cover layer comprises a printed layer to form the light attenuation structure, and the printed layer is located at a projection position of the first color light of the first light source on the light shielding sheet relative to the propagation path of the key.

As an optional technical solution, the backlight module further comprises a reflective sheet disposed under the bottom surface; the reflecting sheet comprises a printed layer forming the light attenuation structure, and the printed layer is positioned at the projection position of the first color light of the first light source relative to the propagation path of the heterochromatic key on the reflecting sheet.

As an optional technical solution, the at least one multi-color light source set is disposed at one side of the light guide plate or is accommodated in the light guide plate.

The invention also provides a light-emitting keyboard, which comprises:

a plurality of keys; and

the backlight module is provided.

Compared with the prior art, the luminous keyboard comprises a plurality of keys and the backlight module arranged under the keys, wherein one of the keys is a different-color key. The backlight module comprises a light guide plate, at least one multicolor light source group, a light attenuation structure and a second optical medium. The light guide plate is composed of a first optical medium; the multi-color light source group is provided with a plurality of multi-color light sources, wherein the first light source is closest to the different-color key; the second optical medium has a refractive index less than the refractive index of the first optical medium. The multicolor light source group is arranged corresponding to the light incident surface of the light guide plate. The second optical medium is arranged between the multicolor light source group and the light incident surface. The light attenuation structure is arranged between the first light source and the heterochromatic keys and attenuates first chromatic light of the first light source passing through or passing through the light attenuation structure. The backlight module and the luminous keyboard can effectively solve the problem of color difference that the luminous color of the key deviates to the color light color of the light source closest to the key, thereby greatly improving the luminous effect and the use impression of the key of the luminous keyboard.

The invention is described in detail below with reference to the drawings and specific examples, but the invention is not limited thereto.

Drawings

Fig. 1A is a schematic top view of a light-emitting keyboard according to a first embodiment of the present invention.

Fig. 1B is a schematic partial cross-sectional view of a light-emitting keyboard according to a first embodiment of the present invention.

Fig. 2A is a partially enlarged top view of the light-emitting keyboard of fig. 1A.

Fig. 2B is a partially enlarged view of fig. 2A.

Fig. 3 is a partially enlarged top view of a light-emitting keyboard according to a second embodiment of the present invention.

Fig. 4 is a schematic partial cross-sectional view of a light-emitting keyboard according to a third embodiment of the present invention.

Fig. 5 is a schematic partial cross-sectional view of a light-emitting keyboard according to a fourth embodiment of the present invention.

Fig. 6 is a partially enlarged top view of the illuminated keyboard of fig. 5.

Fig. 7 is a partially enlarged top view of a light-emitting keyboard according to a fifth embodiment of the present invention.

Fig. 8 is a partially enlarged top view of a light-emitting keyboard according to a sixth embodiment of the present invention.

Detailed Description

In order to further understand the objects, structures, features and functions of the present invention, the following embodiments are described in detail.

Referring to fig. 1A and 1B, and fig. 2A and 2B, fig. 1A is a schematic top view of a light-emitting keyboard 10 according to a first embodiment of the present invention, fig. 1B is a schematic partial cross-sectional view of the light-emitting keyboard 10 according to the first embodiment of the present invention, fig. 2A is an enlarged top view of the light-emitting keyboard 10 of fig. 1B, and fig. 2B is an enlarged partial view of fig. 2A, wherein only a different-color key 16 and a backlight module 14 of the light-emitting keyboard 10 are shown in fig. 2A in order to clearly show a design of the backlight module 14 of the light-emitting keyboard 10. As shown in fig. 1A and 1B and fig. 2A and 2B, the light-emitting keyboard 10 includes a plurality of keys 12 and a backlight module 14. The plurality of keys 12 are located above the backlight module 14 for a user to press to execute a function desired by the user, one of the plurality of keys 12 may be a different color key 16 desired to be illuminated by the backlight module 14, and a key cap 17 of the different color key 16 defines a light emitting area 19 (shown in fig. 2A by a dotted line, and the related description of the design of the light emitting area 19 (such as key characters and the like) is common in the prior art and is not described herein), so as to allow light provided by the backlight module 14 to be emitted to generate a key light emitting effect. In various embodiments, the light exiting area 19 defined by the key cap 17 of each key 12 on the light-emitting keyboard 10 may include any one or more positions within the outline of each key cap 17, the periphery of the outline of the key cap 17, or the spacing region defined between any 2 or more adjacent key caps 17.

Each key 12 comprises a key cap 17, a base plate, a support structure (e.g., a pair of scissor-leg mounts) connecting the key cap 17 to the base plate, and a switching circuit on a thin film circuit board, which may be located on or under the base plate. The base plate and the thin film circuit board have holes H corresponding to the light-emitting area 19 or other light-transmitting areas of the keys 12 for transmitting light.

As shown in fig. 1A and 1B and fig. 2A and 2B, the backlight module 14 is disposed under the plurality of keys 12 and includes a light guide plate 18, at least one multi-color light source set 20 (preferably, three monochromatic leds, red, green and blue, one of which is shown in fig. 2A and 2B, but not limited thereto), at least one second optical medium 22 (preferably, air, but not limited thereto) and a light attenuating structure 24. The light guide plate 18 has a bottom surface 26, a light incident surface 28 and a light emitting surface 30, the bottom surface 26 is adjacent to the light incident surface 28 and opposite to the light emitting surface 30, and the light guide plate 18 may be preferably made of a light transmissive plastic material (such as, but not limited to, Polycarbonate (PC), polymethyl methacrylate (PMMA)). If necessary, the light guide plate 18 may be disposed with a light shielding sheet on the light emitting surface 30 (e.g., the top surface) of the light guide plate 18, and a reflective sheet on the bottom surface 26 of the light guide plate 18. Generally, after entering the light guide plate 18 through the light incident surface 28, the light is totally reflected in the light guide plate 18 until encountering a reflection structure (not shown) of the light guide plate 18, and then is reflected upward and exits through the light exiting surface 30.

The multi-color light source set 20 is disposed corresponding to the light incident surface 28 of the light guide plate 18, and the multi-color light source set 20 is preferably accommodated in the opening of the light guide plate 18 (but not limited thereto, it can also be designed to be disposed on one side of the light guide plate 18), and the multi-color light source set 20 includes a plurality of light sources disposed on a flexible circuit board F1 (schematically shown by a dashed box in fig. 1A), and the plurality of light sources can be a plurality of single-color LED chips packaged separately or three single-color LEDs packaged integrally. The plurality of light sources generate a plurality of different color lights (e.g., three color lights such as red, green and blue), wherein a first light source 32 of the plurality of light sources is close to the first side S1 of the multi-color light source group 20 and is closest to the light exit area 19 of the different-color key 16, and a second light source 34 of the plurality of light sources is close to the second side S2 of the multi-color light source group 20 and is farthest from the light exit area 19 of the different-color key 16. The second optical medium 22 is disposed between the multi-colored light source group 20 and the light-in surface 28 of the light guide plate 18. in this embodiment, the first refractive index of the first optical medium of the light guide plate 18 is greater than the second refractive index of the second optical medium 22.

The light attenuating structure 24 may preferably be designed to be retracted from the light incident surface 28 in a direction away from the first light source 32 at a position corresponding to the first light source 32, for example, as shown in fig. 1A and 1B and fig. 2A and 2B, the light attenuating structure 24 is disposed between the first light source 32 and the different-color key 16 to attenuate the first color light of the first light source 32 passing through the light attenuating structure 24. In more detail, in this embodiment, the light incident surface 28 of the light guide plate 18 may have a first light incident section 36 and a second light incident section 38, wherein the first light incident section 36 is close to the first light source 32, and the second light incident section 38 is close to the second light source 34 (as can be seen from fig. 2A and 2B, a second distance from the second light source 34 to the second light incident section 38 is smaller than a first distance from the first light source 32 to the first light incident section 36), the arrangement directions of the first light incident section 36, the second light incident section 38 and the multi-color light source group 20 are approximately parallel, and the light attenuating structure 24 is disposed between the second light medium 22 and the first light incident section 36 of the light incident surface 28. In the present invention, the light attenuating structure 24 may be comprised of a third optical medium having a third index of refraction; in the present embodiment, the third optical medium is preferably air, that is, the third refractive index is equal to the second refractive index of the second optical medium 22, and the range of the light attenuating structure 24 can be defined by both the partial wall surface of the first light incident section 36 of the light incident surface 28 that is retracted toward the light emergent area 19 of the key cap 17 and the straight extension line of the second light incident section 38 before retraction (as shown in fig. 2A and fig. 2B, but not limited thereto). Although the light attenuating structures 24 and the second optical medium 22 are both air in the embodiment, the first color light emitted from the first light source 32 must pass through the light attenuating structures 24 and is attenuated and attenuated, so that the first color light actually passing through the first light incident section 36 is reduced.

Through the above design, the first color light emitted by the first light source 32 closest to the light exiting region 19 of the different-color key 16 can enter the light guide plate 18 through the light incident surface 28, that is, the first color light can sequentially pass through the second optical medium 22, the light attenuating structure 24, the first light incident section 36 of the light incident surface 28, and the light guide plate 18. The light attenuating structure 24 has a color light attenuating effect, so that when the attenuated first color light is mixed with other color lights of the multi-color light source set 20, the problems of color difference and color cast are avoided, and the first color light is emitted from the light emitting surface 30 of the light guide plate 18 to illuminate the light emitting area 19 of the different-color key 16, so that the key light emitting effect with higher uniformity is generated at the different-color key 16 and nearby positions. Therefore, the problem of color difference that the luminous color of the key deviates to the color light color of the light source closest to the key in the prior art can be effectively solved, and the luminous effect and the use impression of the key of the luminous keyboard are greatly improved.

It should be noted that any light attenuation structure may be adopted in the present invention as long as the light attenuation structure is formed by retracting from the light incident surface in the direction away from the first light source at the position corresponding to the first light source, and the design of the step-shaped retraction described in the above embodiments is not limited.

For example, please refer to fig. 3, which is a partially enlarged top view of a light-emitting keyboard 10 ' according to a second embodiment of the present invention, wherein in order to clearly show the design of the backlight module 14 ' of the light-emitting keyboard 10 ', only the different-color keys 16 and the backlight module 14 ' of the light-emitting keyboard 10 ' are shown in fig. 3. In this embodiment, elements mentioned in the above embodiments have the same number, which means the same or similar structure or function, and the description thereof can refer to the above embodiments and the description thereof is omitted. In this embodiment, as shown in fig. 3, the light-emitting keyboard 10 ' includes a plurality of keys (only the different-color key 16 is shown in fig. 3) and a backlight module 14 ', and the backlight module 14 ' includes a light guide plate 18, a multi-color light source set 20, a second optical medium 22 and a light attenuating structure 24 ', in this embodiment, the light attenuating structure 24 ' is formed by obliquely retracting from a light incident surface 28 of the light guide plate 18 to a position corresponding to the first light source 32 in a direction away from the first light source 32, wherein the light attenuating structure 24 ' may be formed by a third optical medium (preferably air, i.e. the third refractive index is equal to the second refractive index of the second optical medium 22) having a third refractive index, and a range of the light attenuating structure 24 ' may be defined by a partial wall surface of a first light incident section 36 of the light incident surface 28 retracting towards a light emergent region 19 of the key cap 17 and a straight extension line of a second light incident section 38 before retraction (as shown in fig. 3, but not limited thereto). In this embodiment, the first light-entering segment 36 of the light-entering surface 28 is at an angle with respect to the second light-entering segment 38 and the arrangement direction of the multicolor light source group 20, i.e. is not parallel to each other.

Please refer to fig. 4, which is a schematic partial cross-sectional view of a light-emitting keyboard 100 according to a third embodiment of the present invention, wherein the elements in this embodiment have the same numbers as those in the above-mentioned embodiments, which represent the same or similar structures or functions. In this embodiment, as shown in fig. 4, the light-emitting keyboard 100 includes a plurality of keys 12 (two are shown in fig. 4, but not limited thereto) and a backlight module 102, one of the keys 12 is a different-color key 16 to be illuminated by the backlight module 102, the backlight module 102 includes a light guide plate 18, a multi-color light source set 20, a second optical medium 22, and a light attenuating structure 104, the light attenuating structure 104 is preferably an optical microstructure and is formed on the light emitting surface 30 and adjacent to the light incident surface 28 (but not limited thereto, the present invention can also adopt a design in which the optical microstructure is formed on the bottom surface 26 and adjacent to the light incident surface 28), such that a first color light emitted by a first light source 32 closest to a light emitting area 19 of the different-color key 16 can sequentially pass through the second optical medium 22 and pass through the light attenuating structure 104 and the light guide plate 18, thereby the first color light is attenuated by scattering of the optical microstructure, the problem of color difference that the luminous color of the key is biased to the color of the colored light of the light source closest to the key in the prior art is effectively solved, and therefore the luminous effect and the use impression of the key of the luminous keyboard are greatly improved.

In all embodiments of the present invention, the first color light is not limited to pass through (pass through) or pass through (dependent through) the light attenuation structure to achieve the attenuation effect. In the third embodiment (fig. 4), the fourth embodiment (fig. 5 and 6), the fifth embodiment (fig. 7), and the sixth embodiment (fig. 8), the first color light is not limited to the passing (passby) light attenuation structure, and the attenuation effect can be achieved.

In a fourth embodiment, the present invention can adopt a design that the adhesive layer generates light attenuation effect, for example, please refer to fig. 5 and fig. 6, fig. 5 is a partial cross-sectional view of a light-emitting keyboard 150 according to the fourth embodiment of the present invention, fig. 6 is a partial enlarged top view of the light-emitting keyboard 150 of fig. 5, wherein in order to clearly show the design of the backlight module 152 of the light-emitting keyboard 150, only the different-color keys 16 and the backlight module 152 of the light-emitting keyboard 150 are shown in fig. 6. In this embodiment, elements mentioned in the above embodiments have the same number, which means the same or similar structure or function, and the description thereof can refer to the above embodiments and the description thereof is omitted. In this embodiment, as shown in fig. 5 and fig. 6, the light-emitting keyboard 150 includes a plurality of keys 12 (two are shown in fig. 5, but not limited thereto) and a backlight module 152, one of the plurality of keys 12 is a different-color key 16 to be illuminated by the backlight module 152, and the backlight module 152 includes a light guide plate 18, a multi-color light source set 20, a second optical medium 22, a light shielding sheet 154, a reflective sheet 156, and a light attenuating structure 158 a. The light-shielding sheet 154 is disposed on the light-emitting surface 30 of the light guide plate 18 and the reflective sheet 156 is disposed under the bottom surface 26 of the light guide plate 18, the light-shielding sheet 154 may have a covering layer 160, and the covering layer 160 defines a plurality of openings 161 corresponding to the plurality of keys 12, for example, the light-shielding sheet 154 may be made of a transparent material, on which white paint and black paint are sequentially coated to form the covering layer 160, and a plurality of openings 161 (i.e., areas not coated with black paint and white paint) are formed at positions corresponding to the plurality of keys 12, respectively, for transmitting light, but not limited thereto. The light attenuating structure 158a is preferably a part of a semi-transparent adhesive layer 158 (such as, but not limited to, an aqueous adhesive), which has a refractive index greater than the second refractive index of the second optical medium 22, located on the first color light traveling path, the adhesive layer 158 is adhered between the light shielding sheet 154 and the light emitting surface 30 of the light guide plate 18 and between the reflective sheet 156 and the bottom surface 26 of the light guide plate 18, and corresponds to the light incident surface 28 and the first light source 32, and the adhesive layer 158 does not extend to correspond to the second light source 34 (as shown in the non-adhesive region B of fig. 6). In this way, the first color light emitted by the first light source 32 closest to the light emitting area 19 of the different-color key 16 can sequentially pass through the second optical medium 22, the light attenuating structure 158a and the light guide plate 18, and since a part of the first color light enters the light attenuating structure 158a, the part of the first color light is guided to other directions due to the optical diffusion effect of the light attenuating structure 158a and the adhesive layer 158, so that the first color light has the light attenuating effect; in contrast, since the second color light is not attenuated by the light attenuating structure 158a, when reaching the light emitting area 19, the second color light and the first color light have similar luminous fluxes, thereby effectively solving the problem that the key light emitting color is biased to the color closest to the light source color light.

It should be noted that the light attenuation design with the adhesive layer disposed on the light shielding sheet and the light attenuation design with the adhesive layer disposed on the reflective sheet can be set simultaneously or alternatively, so as to simplify the structural design of the backlight module and improve the configuration flexibility of the backlight module.

In addition, the present invention can further adopt an extension design of the adhesive layer to generate the light attenuation effect, please refer to fig. 7, which is a partially enlarged top view of the light-emitting keyboard 150 ' according to a fifth embodiment of the present invention, wherein in order to clearly show the design of the backlight module 152 ' of the light-emitting keyboard 150 ', only the different-color keys 16 and the backlight module 152 ' of the light-emitting keyboard 150 ' are shown in fig. 7. In this embodiment, elements mentioned in the above embodiments have the same number, which means the same or similar structure or function, and the description thereof can refer to the above embodiments and the description thereof is omitted. In this embodiment, as shown in fig. 7, the light-emitting keyboard 150 ' includes a plurality of keys (only the different-color key 16 is shown in fig. 7) and a backlight module 152 ', the backlight module 152 ' includes a light guide plate 18, a multi-color light source set 20, a second optical medium 22, a light shielding sheet 154 and a light attenuating structure 158b, the light attenuating structure 158b is preferably a semi-transparent adhesive layer 158 ' (such as, but not limited to, an aqueous adhesive) having a refractive index greater than a second refractive index of the second optical medium 22, the adhesive layer 158 ' is adhered between the light shielding sheet 154 and the light guide plate 18 and corresponds to the light incident surface 28 and the first light source 32, and the adhesive layer 158 ' has an extension section 159 extending along a light transmission path of the first color light of the first light source 32, such that a portion of the adhesive layer 158 ' and the extension section 159 form the light attenuating structure 158b on the path of the first color light. Since a part of the first color light enters the light attenuating structure 158b, the part of the first color light is guided to other directions due to the optical diffusion effect of the light attenuating structure 158b and the adhesive layer 158', so that the first color light has a light attenuation phenomenon; on the other hand, since the second color light is not attenuated by the light attenuating structure 158b, when reaching the light emitting area 19, the second color light and the first color light have similar luminous fluxes, thereby effectively solving the color shift problem. In addition, the above-mentioned extending design of the adhesive layer can be applied to the reflective sheet, and the related description can be analogized with reference to fig. 7, which is not described herein again.

In another embodiment, the present invention can adopt a design of using a printed layer to generate light attenuation effect, for example, please refer to fig. 8, which is a partially enlarged top view of the light-emitting keyboard 200 according to the sixth embodiment of the present invention, wherein in order to clearly show the design of the backlight module 202 of the light-emitting keyboard 200, only the different-color keys 16 and the backlight module 202 of the light-emitting keyboard 200 are shown in fig. 8. In this embodiment, elements mentioned in the above embodiments have the same number, which means the same or similar structure or function, and the description thereof can refer to the above embodiments and the description thereof is omitted. In this embodiment, as shown in fig. 8, the light-emitting keyboard 200 includes a plurality of keys (only the different-color key 16 is shown in fig. 8) and a backlight module 202, the backlight module 202 includes a light guide plate 18, a multi-color light source set 20, a second optical medium 22, a light-shielding sheet 204, a reflective sheet 207 and a light-attenuating structure, the light-shielding sheet 204 has a cover layer 206, the cover layer 206 defines a plurality of openings to respectively correspond to the plurality of keys and may include a printed layer 208 to form the light-attenuating structure, and the printed layer 208 may be located at a projection position of a propagation path of the first color light of the first light source 32 relative to the different-color key 16 on the light-shielding sheet 204. The printed layer 208 may be a black printed layer to generate a light absorption and attenuation effect, or a printed layer having the same color as the second color light of the second light source 34 to generate a first color light attenuation, or a printed layer having the color of the second color light to adjust the color development effect of the first color light. In this way, through the light absorption or light mixing design of the printed layer 208, the first color light incident on the printed layer 208 is not directly reflected back to the light guide plate 18, so that the color shift problem of the first color light can be solved. In addition, the above printed layer design can be applied to the reflective sheet 207 simultaneously or separately, and the description thereof can be analogized with reference to fig. 8, and will not be repeated herein.

The different color keys 16 described in the above embodiments of the present invention are not limited to the keys 12 closest to the multi-color light source group 20. Wherever the optical paths of the multiple light sources of the multi-color light source set 20 can reach, the keys 12 with the problem of different colors can be regarded as the different color keys 16. For example, in fig. 1A, the optical paths of the light sources of a certain multi-color light source group 20 are indicated by dashed arrows, and each key 12 forming the sector light emitting coverage area has a different color problem, i.e. a different color key 16. Since multiple multi-color light source sets 20 can be disposed to illuminate each key 12, in other words, all keys 12 on the entire illuminated keyboard 10 can be different color keys 16, the technical solutions or combinations thereof of the foregoing embodiments of the present invention can be used for exclusion.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.

In summary, the light-emitting keyboard of the present invention includes a plurality of keys and a backlight module disposed under the plurality of keys, wherein one of the plurality of keys is a different color key. The backlight module comprises a light guide plate, at least one multicolor light source group, a light attenuation structure and a second optical medium. The light guide plate is composed of a first optical medium; the multi-color light source group is provided with a plurality of multi-color light sources, wherein the first light source is closest to the different-color key; the second optical medium has a refractive index less than the refractive index of the first optical medium. The multicolor light source group is arranged corresponding to the light incident surface of the light guide plate. The second optical medium is arranged between the multicolor light source group and the light incident surface. The light attenuation structure is arranged between the first light source and the heterochromatic keys and attenuates first chromatic light of the first light source passing through or passing through the light attenuation structure. The backlight module and the luminous keyboard can effectively solve the problem of color difference that the luminous color of the key deviates to the color light color of the light source closest to the key, thereby greatly improving the luminous effect and the use impression of the key of the luminous keyboard.

The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention.

Claims (12)

1. A backlight module is used for being arranged under a plurality of keys of a luminous keyboard, one of the keys is a different-color key, a keycap of the different-color key defines a light emitting area, and the backlight module comprises:

the light guide plate is provided with a bottom surface, a light incident surface and a light emergent surface, wherein the bottom surface is adjacent to the light incident surface and is opposite to the light emergent surface;

at least one multicolor light source group which is arranged corresponding to the light inlet surface of the light guide plate and comprises a plurality of light sources, the plurality of light sources generate a plurality of color lights which are different from each other, a first light source in the plurality of light sources is positioned at a first side of the multicolor light source group and is closest to the light outlet area of the different-color key, and a second light source in the plurality of light sources is positioned at a second side of the multicolor light source group and is farthest from the light outlet area of the different-color key;

at least one second optical medium arranged between the multi-color light source group and the light incident surface of the light guide plate, wherein the first refractive index of the first optical medium is greater than the second refractive index of the at least one second optical medium; and

the light attenuation structure is arranged between the first light source and the heterochromatic key and attenuates first chromatic light of the first light source passing through the light attenuation structure;

the first color light enters the light guide plate through the light incident surface, and the first color light sequentially passes through the second optical medium, the light attenuation structure and the light guide plate, so that the attenuated first color light and other color lights generated by the multi-color light source set generate mixed light, and the mixed light is emitted from the light emitting surface of the light guide plate to illuminate the light emitting area of the different-color key.

2. The backlight module of claim 1, wherein the light incident surface of the light guide plate has a first light incident section and a second light incident section, the first light incident section is close to the first light source, the second light incident section is close to the second light source, and a second distance from the second light source to the second light incident section is smaller than a first distance from the first light source to the first light incident section.

3. The backlight module of claim 2, wherein the light attenuating structure is disposed between the second light medium and the first light incident section of the light incident surface, the light attenuating structure being formed of a third medium having a third refractive index not less than the second refractive index of the second medium.

4. The backlight module of claim 1, wherein the light attenuating structure is an optical microstructure formed on the light emitting surface or the bottom surface and adjacent to the light incident surface.

5. The backlight module as claimed in claim 1, further comprising a light shielding sheet having a covering layer disposed on the light emergent surface, the covering layer defining a plurality of openings corresponding to the plurality of keys respectively; the light attenuation structure is a semi-transparent adhesive layer, the adhesive layer is adhered between the shading sheet and the light guide plate, the adhesive layer corresponds to the light incident surface and the first light source, and the adhesive layer does not extend to correspond to the second light source.

6. The backlight module of claim 1, further comprising a reflector disposed under the bottom surface; the light attenuation structure is a semi-transparent adhesive layer, the adhesive layer is adhered between the reflector plate and the light guide plate, the adhesive layer corresponds to the light incident surface and the first light source, and the adhesive layer does not extend to correspond to the second light source.

7. The backlight module of claim 1, further comprising a reflector disposed under the bottom surface; the light attenuation structure is a semi-transparent adhesive layer, the adhesive layer is adhered between the reflection sheet and the light guide plate and corresponds to the light incident surface and the first light source, and the adhesive layer is provided with an extension section extending along a light transmission path of the first color light of the first light source.

8. The backlight module as claimed in claim 1, further comprising a light shielding sheet having a covering layer disposed on the light emergent surface, the covering layer defining a plurality of openings corresponding to the plurality of keys respectively; the light attenuation structure is a semi-transparent adhesive layer, the adhesive layer is adhered between the shading sheet and the light guide plate, the adhesive layer corresponds to the light incident surface and the first light source, and the adhesive layer is provided with an extension section which extends along the light transmission direction of the first color light of the first light source.

9. The backlight module as claimed in claim 1, further comprising a light shielding sheet having a covering layer disposed on the light emergent surface, the covering layer defining a plurality of openings corresponding to the plurality of keys respectively; the cover layer comprises a printed layer to form the light attenuation structure, and the printed layer is located at a projection position of the first color light of the first light source on the light shielding sheet relative to the propagation path of the key.

10. The backlight module of claim 1, further comprising a reflector disposed under the bottom surface; the reflecting sheet comprises a printed layer forming the light attenuation structure, and the printed layer is positioned at the projection position of the first color light of the first light source relative to the propagation path of the heterochromatic key on the reflecting sheet.

11. The backlight module of claim 1, wherein the at least one multicolor light source set is disposed at one side of the light guide plate or accommodated in the light guide plate.

12. A light-emitting keyboard comprising a plurality of keys and the backlight module of any one of claims 1-11.

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