TW202414479A - Backlight module and backlight keyswitch thereof - Google Patents

Abstract

A backlight module for illuminating a keycap includes a shielding sheet, a light guide panel, a lighting board disposed under the light guide panel, and a first protrusion structure. The shielding sheet includes a light-permeable area. The light guide panel is disposed under the shielding sheet and has a light guide hole for containing a light source of the lighting board. The first protrusion structure is formed on the shielding sheet and protrudes toward the light source. The first protrusion structure is at least partially not overlapped with the light source in a vertical direction, for reflecting and diffusing at least partial light of the light source to enter the light guide panel for lateral transmission.

Description

Backlight module and backlight button

The present invention relates to a backlight module and a backlight key thereof, and in particular to a backlight module and a backlight key thereof having a protruding structure protruding toward a light source and not overlapping with the light source in a vertical direction, so that more light from the light source enters a light guide plate for horizontal transmission.

With the development of technology, keyboard designs are becoming more and more diverse. When users choose a keyboard, in addition to the basic input functions, the keyboard's visual effects are also important to users. Currently, luminous keyboards are available on the market. In addition to being needed at night or in environments with insufficient lighting, they can also provide users with visual feedback. When a luminous keyboard uses a low-brightness LED to illuminate each square key, the following problems will occur: (1) the main symbol above the LED is too bright, while the corner symbol of the keycap is too dark; (2) the brightness of the halo at the edge of the keycap is inconsistent; and (3) the overall illumination of a single key is inconsistent with that of multiple keys.

According to one embodiment, the backlight module provided by the present invention is used to illuminate at least one keycap and includes a shading sheet, a light guide plate, a lamp plate, and a first protruding structure. The shading sheet has a light-transmitting area. The light guide plate is disposed under the shading sheet and has a light guide hole. The lamp plate is disposed under the light guide plate and has a light source accommodated in the light guide hole. The first protruding structure is formed on the shading sheet and protrudes toward the light source. The first protruding structure does not overlap with the light source at least partially in a vertical direction. The first protruding structure reflects and diffuses at least a portion of the light of the light source to enter the light guide plate for lateral transmission.

According to another embodiment, the backlight key provided by the present invention comprises a key cap, a bottom plate, and the backlight module. The bottom plate is located below the key cap, and the backlight module is arranged under the bottom plate.

According to another embodiment, the backlight key provided by the present invention includes a key cap, a base plate, and a backlight module. The base plate is located below the key cap. The backlight module is arranged under the base plate, and the backlight module includes a shading sheet, a light board, and a light guide plate. The shading sheet has a light-transmitting area corresponding to the key cap. The light board is arranged under the shading sheet and has a light source. The light guide plate has a light guide hole to accommodate the light source, and the edge of the light guide hole forms a slope structure obliquely facing the shading sheet, so that at least part of the light of the light source enters the light guide plate through the slope structure and is transmitted laterally.

In summary, the present invention adopts the arrangement of non-overlapping protruding structures and light sources in the vertical direction, and the light from the light source can be reflected and diffused at the initial stage of the light path by the protruding structure protruding toward the light source, so as to open the light transmission angle, increase the lateral transmission component, and increase the amount of light entering the light guide plate. In this way, in addition to preventing the middle characters from being too bright, the brightness of the side or corner characters is also increased, thereby greatly improving the lighting uniformity of the backlit keys 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.

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 functions 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 various 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 configuration relationships of each component in the drawings (such as the size of the through hole, the proportion of the ink layer, etc.) are only for exemplary purposes and do not represent the actual situation of the implementation of the present invention. The components mentioned in the following embodiments or general descriptions of the present invention have the same name and/or the same number, which represent the same or similar structures and functions, and will not be repeated.

Each embodiment of the present invention aims to increase the proportion of lateral transmission of the light source, that is, to reduce the light output of the main characters on the keycaps corresponding to the surrounding area directly above the light source, and to increase the light output of the characters on the sides or corners of the keycaps. Low-power light sources such as mini LEDs or micro LEDs are used in low-travel keys with a short vertical light output distance (1-2 mm), and a large target light output area (covering the main character/sub-character/keycap edge halo) (about 10-12 mm). If the number and power of light sources are not increased, pure optical means must be used to prevent light from escaping. However, in a small space, how to allow 80% of the light sources that emit light upward to open the light transmission angle so that most of the light enters the light guide plate for lateral transmission is a major problem. Another problem is that if the light is allowed to diffuse through multiple reflections around the light source before the light transmission direction/angle is smoothly converted to lateral transmission inside the light guide plate (for example, reaching the critical angle of total reflection), the light will be wasted unnecessarily at the beginning of the light source. Therefore, reducing the initial loss is another difficult problem.

Please refer to FIG. 1, FIG. 2 and FIG. 3. FIG. 1 is a cross-sectional schematic diagram of a backlight key 10 according to an embodiment of the present invention. FIG. 2 is an exploded schematic diagram of the bottom plate 14, the light shielding sheet 26, the light guide plate 28, and the light board 30 of FIG. 1. FIG. 3 is a stacked schematic diagram of the backlight keyboard 10 applicable to the embodiment of the present invention. The backlight key 10 can be preferably applied to general electronic devices, such as a backlight keyboard LKB of a notebook computer or an independent keyboard device, but is not limited thereto. The backlight key 10 provides a character illuminating function so that the user can recognize and press to input text, numbers, symbols or perform other functions. As shown in FIG. 1 and FIG. 2 , the backlight key 10 includes a key body 12, a bottom plate 14, and a backlight module 18. As shown in FIG. 1 , the key body 12 may include a key cap 20, a lifting mechanism 22, and a reset member 24. The bottom plate 14 is disposed under the key body 12 and the key cap 20, and is connected to the key body 12 and the key cap 20, so that the key body 12 and the key cap 20 can move up and down relative to the bottom plate 14. The base plate 14 has one or more through holes 15 at positions corresponding to the key body 12 (in FIG. 1 , one through hole 15 in the middle and four through holes 15 in the side positions are shown, but the positions and number of the through holes are not limited thereto. For example, a design in which there is no hole in the middle of the base plate and light is emitted only through the side through holes can be adopted). When the base plate 14 is opaque (such as made of metal or opaque material), the through holes 15 allow light from the backlight module 18 to pass through and illuminate the key 20. The backlight key 10 may further include a thin film circuit board 16 (but not limited thereto), which is arranged parallel to the key cap 20 and the base plate 14, for example, between the key body 12 and the base plate 14, or below the base plate 14. The thin film circuit board 16 has a key circuit connected to a plurality of switches, which correspond to each backlight key 10 respectively, and can generate corresponding key signals when triggered. The lifting mechanism 22 is connected between the key cap 20 and the base plate 14, and the lifting mechanism 22 can rotate and/or move to support the key cap 20 to move up and down. The reset member 24 is elastic and can provide a restoring force to support the key cap 20 to return to the initial position when under pressure. The key body 12 also includes a triggering part arranged on the lower surface of one of the key cap 20, the reset member 24 or the lifting mechanism 22, which can move up and down with the key cap 20 to trigger the switch of the thin film circuit board 16, thereby generating a key signal.

In detail, as can be seen from FIG. 1 and FIG. 3, the backlight module 18 is disposed below the key body 12, the key cap 20 and the bottom plate 14. The backlight module 18 includes a light shielding sheet 26, a light guide plate 28, a light plate 30, and a first protruding structure 32, wherein the through hole 15 of the bottom plate 14 can preferably surround the first protruding structure 32 in the vertical direction V (but not limited thereto). In a broad sense, the backlight module 18 can also include the bottom plate 14 and the thin film circuit board 16, because in theory these multi-layer stacking structures can integrate circuits and components to reduce the total number of layers. To ensure that the light escaping from the light guide plate 28 can be recovered to the light guide plate 28 for continued transmission, the light panel 30 and the light shielding film 26 have a first reflective layer 42 and a second reflective layer 38 on the upper and lower surfaces facing the light guide plate 28, respectively.

The shading sheet 26 is disposed between the bottom plate 14 and the light guide plate 28. For example, the shading sheet 26 may be provided with the aforementioned second reflective layer 38 on a transparent substrate to reduce and/or prevent light from passing through a specific portion. At the light-emitting position corresponding to the key body 12 (such as characters and halo), the shading sheet 26 is not provided with the second reflective layer 38 so as to form a light-transmitting area 27. The second reflective layer 38 may be a white ink or paint layer, or may be implemented by a paint with highly reflective particles, or even a metal layer or metal paint. The second reflective layer 38 generally has a reflectivity of at least 15-20%. If necessary, the second reflective layer 38 may also have a considerable transmittance to allow local light to pass through. The second reflective layer 38 may include an inner reflective area 38a (block-shaped), an outer reflective area 38b (frame-shaped), and a rib reflective area 38c (if necessary). The light-transmitting area 27 surrounds the inner reflection area 38a, and the outer reflection area 38b surrounds the light-transmitting area 27, so that the light-transmitting area 27 surrounds the inner reflection area 38a and the outer reflection area 38b. The outer reflection area 38b corresponds to the inner and outer areas around the key cap 20, so as to prevent the user from seeing the highlights (such as the microstructures described later) below the through hole 15 of the bottom plate 14 through the gap around the key cap 20. The rib reflection area 38c is disposed between the inner reflection area 38a and the outer reflection area 38b, and each is spaced a distance apart. The inner reflection area 38a corresponds to and covers the light source 34, so as to allow the strongest light to be reflected into the light guide plate 28, avoid the problem of the main characters of the key cap 20 being too bright, help improve the brightness of the edge or corner characters, and also help improve the luminous uniformity of the backlight key 10. If necessary, the backlight module 18 may further include a mask layer 40, which may be formed above the light shielding sheet 26 and cover the light source 34 in the vertical direction V to further shield the light penetrating the second reflection layer 38. The mask layer 40 may be a black ink layer or a metal paint layer, and is formed above the second reflection layer 38 corresponding to the position of the light source 34. The mask layer 40 can be divided into an inner mask area 40a, an outer mask area 40b and a rib mask area 40c. In addition, in practical applications, the mask layer 40 may have at least one light-filling hole 41 (two are shown in FIG. 1, but not limited thereto). Thus, in addition to shielding the light that penetrates the second reflective layer 38, the mask layer 40 may also allow the light emitted upward by the light source 34 to pass through the light-filling hole 41, the through hole 15 and the thin film circuit board 16 and be incident on the key cap 20 to produce a brightness compensation effect, thereby further improving the light uniformity of the backlight key 10.

The light guide plate 28 is located below the light shielding sheet 26, and the light board 30 is disposed below the light guide plate 28 and has a light source 34. The light guide plate 28 has a light guide hole 29 (preferably a round hole, but not limited thereto, the present invention can also adopt other light guide hole designs, such as a square hole, etc.) at a position corresponding to the key body 12/key cap 20/light source 34. The light source 34 is disposed in the light guide hole 29, and one or more first protruding structures 32 are at least partially located in the light guide hole 29. The first reflective layer 42 and the second reflective layer 38 can overlap the first protruding structure 32 and the light guide hole 29 at least partially in the vertical direction V. The light source 34 includes one or more light-emitting bodies, such as single-color or multiple light-emitting diode chips of different colors. The light source 34 also has a fluorescent body with diffusion, dimming or mixing effects encapsulated on the surface of the chip, but not limited thereto. The light emitting range of the light source 34 includes, for example, the top surface and four side surfaces, and the first protruding structure 32 is at least partially located within the light emitting range of the light source 34. The closer the first protruding structure 32 is to the light source 34, the more a portion of the light rays can directly reach the first protruding structure 32 and be reflected and diffused as soon as it leaves the light source 34; another portion of the light rays are reflected by the second reflective layer 38 of the light shielding sheet 26, and then refracted and diffused through the first protruding structure 32. The backlight module 18 further includes a microstructure layer 36, and the microstructure layer 36 can be arranged parallel to the light guide plate 28 and the lamp board 30. The microstructure layer 36 is arranged correspondingly in the area below the main character/sub-character of the key cap 20, such as formed on the upper surface or lower surface of the light guide plate 28, or formed on the upper surface of the reflective layer of the lamp board 30, or independently formed between the light guide plate 28 and the lamp board 30. The microstructure layer 36 is a diffusion structure, such as metal paint/white paint microdots, concave-convex microdot structures, linear concave-convex structures composed of line segments or continuous lines, etc.

Please refer to FIG. 1 and FIG. 4. FIG. 4 is a top perspective view of the configuration of the key cap 20, the bottom plate 14, the first protruding structure 32 and the light source 34 of FIG. 1. As can be seen from FIG. 1 and FIG. 4, the first protruding structure 32 protrudes toward the light source 34. The first protruding structure 32 can be formed on the light shielding sheet 26 and at least partially does not overlap with the light source 34 in the vertical direction V. The first protruding structure 32 can be at least partially transparent. Alternatively, the surface of the first protruding structure 32 can also have good reflectivity by utilizing material properties or structural properties. The first protruding structure 32 can be fixed on the surface of the light shielding sheet 26 as an independent element (for example, by printing or dotting paint, ink or glue to form bumps or particles), or can be integrally formed by the light shielding sheet 26 (for example, by stamping with a mold). The height of the first protruding structure 32 can be, for example, 18% to 95% of the thickness of the light guide plate 28. The main purpose of providing the first protruding structure 32 is to diffuse the light and open or increase the light transmission angle (relative to the top normal of the light source 34), that is, to allow the light to have a larger lateral transmission component, so that more light can enter the light guide plate 28 at the initial stage of light emission and be transmitted laterally in the light guide plate 28 through total reflection; further, in this embodiment, the light guide hole 29 can be preferably expanded outward to form an expansion area 31 corresponding to the first protruding structure 32 in the vertical direction V, so as to allow at least part of the light from the light source 34 to be reflected and diffused by the first protruding structure 32 in the expansion area 31 and then transmitted laterally to the light guide plate 28 (as shown in Figure 1), thereby increasing the proportion of lateral transmission of the light source. It should be noted that the present invention may also omit the above-mentioned hole enlargement design. For example, as shown in FIG. 5, in the design without enlarging the light guide hole 29, the first protrusion structure 32 may be formed outside the light guide hole 29 and overlap with the light guide plate 28 in the vertical direction V, so as to further reduce the optical coupling distance between the first protrusion structure 32 and the light guide plate 28 and increase the amount of light entering the light guide plate 28. Although the drawings of the present invention use a larger size to draw the light guide hole 29 or the hole expansion area 31 for the convenience of showing details, in the implementation of a square key cap with a side length of 12-15 mm, the side length of the light guide hole 29 or the hole expansion area 31 may be only 0.5 to 1.2 mm, and each first protrusion structure 32 may have a diameter of no more than 0.1 mm.

The diffusion effect of the first protruding structure 32 can come from the second reflective layer 38 (internal reflection area 38a) or the first protruding structure 32 itself; the first protruding structure 32 is made of a reflective material, or the first protruding structure 32 has a smooth or rough curved surface, so that the first protruding structure 32 can provide the effect of diffusing light without the second reflective layer 38 (internal reflection area 38a). The first protruding structure 32 can have a single or multiple protrusions or form multiple concave and convex areas to surround the light source 34, such as an elliptical hemisphere with 360 degrees horizontally and 120 degrees vertically. As shown in FIG. 4 , the first protrusion structure 32 is preferably composed of a plurality of scattering protrusions 33 arranged at intervals around the light source 34, but this is not limited to the present invention, which means that the present invention can also adopt other continuous or discontinuous protrusion structure configurations. For example, please refer to FIG. 6 , which is a diagram of different protrusion structure configurations proposed according to different embodiments of the present invention. As shown in FIG. 6 (a), the first protruding structure 32 may be composed of at least two arc-shaped scattering layers 33' formed discontinuously around the surrounding light source 34; as shown in FIG. 6 (b), the first protruding structure 32 may be an annular scattering layer 33" formed continuously around the surrounding light source 34. Regardless of whether the first protruding structure 32 is composed of a plurality of scattering bumps 33, or is composed of at least two arc-shaped scattering layers 33', or is implemented by an annular scattering layer 33", the first protruding structure 32 The lowest point of the first protruding structure 32 does not overlap with the light source 34. This means that the first protruding structure 32 is staggered with the light source 34. In this way, the inclined surface or inclined curved surface (or other regular or irregular surface that is neither horizontal nor vertical) of the first protruding structure 32 is directed toward the light source 34, so as to refract, reflect and/or diffuse the light directly or indirectly coming from the light source 34, the second reflective layer 38 of the light shielding sheet 26 or the first reflective layer 42 of the light panel 30, thereby increasing the proportion of light entering the light guide plate 28 and transmitted laterally.

The above-mentioned protruding structure design can also be applied to the lamp panel. For example, as shown in FIG. 1, the backlight module 18 can further include a second protruding structure 32', which is formed on the lamp panel 30 and at least partially surrounds the light source 34. In this way, the second protruding structure 32' can diffuse the light of the light source 34 and open or increase the light transmission angle (relative to the top surface normal of the light source 34), that is, the light can have a larger lateral transmission angle. The amount of light can be increased, so that more light can enter the light guide plate 28 at the initial stage of light emission, and be transmitted laterally in the light guide plate 28 through total reflection, wherein the second protruding structure 32' is fixed on the surface of the light board 30 as an independent element (for example, by printing or dotting paint, ink or glue to form a protrusion), or can be integrally formed by the light board 30 (for example, by stamping with a mold), and the height of the second protruding structure 32' can be, for example, 18% to 95% of the thickness of the light guide plate 28. As for the relevant description of different structural configurations of the second protruding structure 32' (such as scattering protrusion configuration, arc scattering layer configuration, annular scattering layer configuration, etc.), it can be referred to Figure 6 by analogy, and will not be repeated here.

In addition, the present invention can further adopt a glue layer design. For example, as shown in FIG. 1, the backlight module 18 can further include at least one glue layer 44. FIG. 1 shows a glue layer 44 attached between the light shielding sheet 26 and the light guide plate 28. The glue layer 44 at least partially surrounds the first protruding structure 32/the second protruding structure 32', the light guide hole 29 and the light source 34 in the vertical direction V. FIG. 1 also shows another glue layer 44 attached between the light guide plate 28 and the first reflective layer 42. The glue layer 44 also at least partially surrounds the first protruding structure 32/the second protruding structure 32', the light guide hole 29 and the light source 34 in the vertical direction V. The aforementioned glue layer 44 is arranged parallel to the light shielding sheet 26, the light guide plate 28, and the light panel 30. The light guide plate 28 has a non-adhesive area 45 between the adhesive layer 44 and the first protruding structure 32 to prevent the adhesive layer 44 from entering the light guide hole 29 of the light guide plate 28 and adhering to the light source 34 during the manufacturing process, resulting in excessive light emission or the light source 34 falling off. The non-adhesive area 45 can be set on the upper surface of the light guide plate 28 (or between the light guide plate 28 and the light shielding sheet 30), and the non-adhesive area 45 can also be set on the lower surface of the light guide plate 28 (or between the light guide plate 28 and the light board 32). The adhesive layer 44 has a good light coupling effect. Through the design of the above-mentioned adhesive layer 44, the light from the light source 34 can smoothly reach the medium on the other side of the adhesive layer 44 when it is directly or indirectly incident on the adhesive layer 44, so that the light can be reflected back to the light guide plate 28 between the second reflective layer 38 and the first reflective layer 42 after emitting from the light guide plate 28, so as to avoid the light from being dissipated and lost in the air gap between the light guide plate 28 and the shading sheet 26, or in another air gap between the light guide plate 28 and the lamp panel 30 and the first reflective layer 42, so as to ensure that a sufficient proportion of light can continue to be transmitted horizontally in the light guide plate 28 to a farther position.

Through the above configuration, the first protruding structure 32/the second protruding structure 32' can diffuse the light and open or increase the light transmission angle (relative to the top normal of the light source 34), increase the lateral transmission component of the light, and allow more light to enter the light guide plate 28 for lateral transmission at the initial stage of light emission. Then, through the optical coupling effect of the glue layer 44 surrounding the first protruding structure 32/the second protruding structure 32', the initial scattered light can be guided back to the light guide plate 28. In addition, the light scattered from the upper and lower surfaces of the light guide plate 28 can be reflected and recycled to the light guide plate 28 through the first reflective layer 42 and the second reflective layer 38, ensuring that as much light as possible reaches the bottom of the side and corner of the key cap 20. At this time, the light can be diffused upward through the microstructure layer 36 (as shown in FIG. 1 ), so that the light can pass upward through the light guide plate 28. In this way, the light can continue to pass through the light-transmitting area 27 of the light shielding sheet 26, the through hole 15 of the bottom plate 14, and the thin film circuit board 16 in sequence and emit from the key cap 20, thereby generating the character luminescence of the key cap 20 and the surrounding halo effect, and achieving a considerable degree of uniformity.

In summary, the present invention adopts the arrangement of non-overlapping protruding structures and light sources in the vertical direction, and the light from the light source can be reflected and diffused at the initial stage of the light path by the protruding structure protruding toward the light source, so as to open the light transmission angle, increase the lateral transmission component, and increase the amount of light entering the light guide plate 28. In this way, in addition to preventing the middle characters from being too bright, the brightness of the side or corner characters is also increased, thereby greatly improving the lighting uniformity of the backlit keys and the visual aesthetic effect when in use.

It is worth mentioning that the present invention can also adopt a light guide plate inclined surface structure design to increase the ratio of lateral transmission of light source. For example, please refer to FIG. 7, which is a cross-sectional schematic diagram of a backlight key 100 proposed according to another embodiment of the present invention. The components shown in this embodiment diagram and the above embodiment diagram have the same number, which represents the same or similar structure and function, and will not be repeated here. As shown in FIG. 7 , the backlight key 100 may include a key body 12, a bottom plate 14, a thin film circuit board 16, and a backlight module 102. The backlight module 102 includes a light shielding sheet 26, a light board 30, and a light guide plate 104. In this embodiment, the inner mask area 40a and the inner reflection area 38a are respectively formed on the upper surface and the lower surface of the light shielding sheet 26 (but not limited to this, for example, they can also be uniformly arranged on the upper surface (as shown in FIG. 1 ) or the lower surface of the light shielding sheet 26). The light guide plate 104 has a light guide hole 106 for accommodating the light source 3 4. The light guide hole 106 forms an inclined surface structure 107 (which can be formed by extending continuously or discontinuously along at least a partial edge of the light guide hole 106) outwardly relative to the light source 34, and is inclined to face the light shielding sheet 26. The inclined surface structure 107 is at least partially higher than the light source 34 in the vertical direction V relative to the light board 30. The first reflection layer 42/the second reflection layer 38 can overlap with the light guide hole 106 and the inclined surface structure 107 at least partially in the vertical direction V. The through hole 15 of the bottom plate 14 can preferably surround the inclined surface structure 107 in the vertical direction V (but not limited to this).

Through the above design, at least part of the light from the light source 34 can enter the light guide plate 104 through the inclined structure 107 and be transmitted laterally. More specifically, the light from the light source 34 can enter the light guide plate 104 through at least three light paths and be transmitted laterally. As shown in FIG. 7 , the light can be emitted from the top surface of the light source 34 and incident on the inclined structure 107 after being reflected by the second reflective layer 38 (the light path is indicated by a thick solid arrow). Alternatively, the light may be emitted from the top surface of the light source 34 and incident on the bottom surface of the light guide plate 104 after being reflected by the second reflective layer 38 and the first reflective layer 42 in sequence (the light path is briefly indicated by a dotted arrow), or the light may be emitted from the side surface of the light source 34 and transmitted laterally to a farther distance by total reflection when directly incident on the inclined surface structure 107 (the light path is briefly indicated by a thin solid arrow). In this way, by designing the light guide plate with the inclined surface structure at least partially higher than the light source, the present invention can effectively increase the proportion of the light source being transmitted laterally, thereby avoiding the middle character from being too bright, and also increasing the brightness of the side or corner characters, thereby greatly improving the luminous uniformity of the backlit keys and the visual aesthetic effect when in use. In practice, the optical designs mentioned in the above embodiments (such as the protruding structure design, the expansion area design, the adhesive layer/no-adhesive area design, etc.) can be selectively applied in this embodiment, and the related descriptions (such as the adhesive layer can be arranged parallel to the light guide plate and at least partially surround the inclined surface structure in the vertical direction, the light guide plate can have a no-adhesive area located between the adhesive layer and the inclined surface structure, etc.) can be analogized based on the above embodiments, and will not be repeated here. The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

10, 100: backlight key 12: key body 14: bottom plate 15: through hole 16: thin film circuit board 18, 102: backlight module 20: key cap 22: lifting mechanism 24: reset member 26: light shielding sheet 27: light transmission area 28, 104: light guide plate 29, 106: light guide hole 30: lamp plate 31: expansion area 32: first protruding structure 32': second protruding structure 33: scattering bump 33': arc scattering layer 33": annular scattering layer 34: light source 36: microstructure layer 38: second reflection layer 38a: inner reflection area 38b: outer reflection area 38c: rib reflection area 40: mask layer 40a: inner mask area 40b: outer mask area 40c: rib mask area 41: fill light hole 42: first reflective layer 44: adhesive layer 45: non-adhesive area 107: inclined structure LKB: backlit keyboard V: vertical direction

Figure 1 is a simplified cross-sectional diagram of a backlight key according to one embodiment of the present invention. Figure 2 is an exploded simplified diagram of the base plate, shading sheet, light guide plate, and light panel of Figure 1. Figure 3 is a stacked schematic diagram of a backlight keyboard applicable to the embodiment of the present invention. Figure 4 is a top perspective diagram of the configuration of the key cap, base plate, first protruding structure, and light source of Figure 1. Figure 5 is a simplified cross-sectional diagram of a backlight key according to another embodiment of the present invention. Figure 6 is a diagram of different protruding structure configurations according to different embodiments of the present invention. Figure 7 is a simplified cross-sectional diagram of a backlight key according to another embodiment of the present invention.

10: Backlit buttons

12: Keyboard

14: Base plate

15:Through hole

16: Thin film circuit board

18: Backlight module

20: Keycaps

22: Lifting mechanism

24: Reset piece

26: Shading film

27: Translucent area

28: Light guide plate

29: Light guide hole

30: Light board

31: Expansion area

32: First protruding structure

32’: Second protruding structure

34: Light source

36: Microstructure layer

38: Second reflective layer

38a: Internal reflection area

38b: External reflection area

38c: Rib reflexology area

40: Mask layer

40a: Inner mask area

40b: Outer mask area

40c: Rib mask area

41: Filling hole

42: First reflection layer

44: Adhesive layer

45: No glue area

V: vertical direction

Claims (20)

A backlight module is used to illuminate at least one keycap, and the backlight module comprises: a light shielding sheet having a light-transmitting area; a light guide plate disposed under the light shielding sheet and having a light guide hole; a light board disposed under the light guide plate and having a light source accommodated in the light guide hole; and a first protruding structure formed on the light shielding sheet and protruding toward the light board, the first protruding structure does not overlap with the light source at least partially in a vertical direction, and the first protruding structure reflects and diffuses at least partial light of the light source to enter the light guide plate for horizontal transmission. The backlight module as described in claim 1 further comprises: A first reflective layer formed on the light panel, the first reflective layer at least partially overlaps with the first protruding structure and the light guide hole in the vertical direction. The backlight module as described in claim 1 further comprises: A second reflective layer formed on the light shielding sheet and at least partially overlapping with the first protruding structure and the light guide hole in the vertical direction. The backlight module as described in claim 1 further comprises: A mask layer formed above the light shielding sheet and covering the light source in the vertical direction. The backlight module as described in claim 1, wherein the first protruding structure is composed of a plurality of scattering protrusions arranged at intervals around the light source, or is composed of at least two arc-shaped scattering layers formed discontinuously around the light source, or is an annular scattering layer formed continuously around the light source. The backlight module as described in claim 1 further comprises: A second protruding structure formed on the light panel and at least partially surrounding the light source, the second protruding structure reflects and diffuses at least part of the light from the light source to enter the light guide plate for lateral transmission. A backlight module as described in claim 1, wherein the lowest point of the first protruding structure does not overlap with the light source. The backlight module as described in claim 1 further comprises at least one glue layer arranged parallel to the light guide plate and at least partially surrounding the first protruding structure in the vertical direction. The backlight module as described in claim 1 further comprises at least one adhesive layer arranged parallel to the light guide plate, and the light guide plate has a non-adhesive area located between the at least one adhesive layer and the first protruding structure. A backlight module as described in claim 1, wherein the first protruding structure is formed on the outer side of the light guide hole and overlaps with the light guide plate in the vertical direction. A backlight key, comprising: a key cap; a base plate located below the key cap; a backlight module as described in claim 1 to 10, disposed under the base plate. A backlight key as described in claim 11, wherein the base plate has a plurality of through holes surrounding the first protruding structure in the vertical direction. A backlight key, comprising: a key cap; a bottom plate, located below the key cap; a backlight module, disposed below the bottom plate, the backlight module comprising: a light shielding sheet, having a light-transmitting area corresponding to the key cap; a light board, disposed below the light shielding sheet and having a light source; and a light guide plate, having a light guide hole to accommodate the light source, the edge of the light guide hole forming a slope structure obliquely facing the light shielding sheet, so that at least part of the light from the light source enters the light guide plate through the slope structure and is transmitted laterally. The backlight key as described in claim 13, wherein the backlight module further comprises: A first reflective layer formed on the light panel, the first reflective layer at least partially overlaps with the light guide hole and the inclined surface structure in the vertical direction. The backlight key as described in claim 13, wherein the backlight module further comprises: A second reflective layer formed on the light shielding sheet and at least partially overlapping with the light guide hole and the inclined surface structure in the vertical direction. The backlight module as described in claim 13, wherein the backlight module further comprises: A mask layer formed above the light shielding sheet and covering the light source in the vertical direction. The backlight module as described in claim 13, wherein the backlight module further comprises: A first protruding structure formed on the light shielding sheet and protruding toward the light board, the first protruding structure does not overlap with the light source at least partially in the vertical direction, and the first protruding structure reflects and diffuses at least part of the light from the light source to enter the light guide plate for lateral transmission. A backlight key as described in claim 13, wherein the backlight module further comprises at least one glue layer arranged parallel to the light guide plate and at least partially surrounding the inclined structure in the vertical direction. A backlight key as described in claim 13, wherein the backlight module further comprises at least one glue layer arranged parallel to the light guide plate, and the light guide plate has a glue-free area located between the at least one glue layer and the inclined structure. A backlight key as described in claim 13, wherein the base plate has a plurality of through holes surrounding the inclined structure in the vertical direction.

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