TWI851185B - Lighting keyboard and backlight module thereof - Google Patents

Abstract

A backlight module includes a lighting board, a light guide panel, a shielding sheet, and a protrusion structure. The lighting board includes two non-intersected traces, a plurality of microstructure regions and at least one illuminant unit. The illuminant unit is connected between the microstructure regions. The microstructure regions do not overlap with the two non-intersected traces. The light guide panel is disposed above the lighting board, and the shielding sheet is disposed above the light guide panel. The protrusion structure is formed on the shielding sheet, protrudes towards the lighting board, and is between the microstructure regions. The protrusion structure diffuses light of the illuminant unit at an early section of its light path to enter into the light guide panel for lateral transmission. The plural microstructure regions reflect and recycle the light at a following section of the light path to jointly enhance the uniformity of illuminating a keycap.

Description

Illuminated keyboard and its backlight module

The present invention relates to a luminous keyboard and a backlight module, and in particular to a luminous keyboard and a backlight module that can improve the consistency of overall luminescence.

With the development of technology, keyboard designs are becoming more and more diverse. When users choose a keyboard, in addition to the basic input function, the keyboard's visual effect is also valued by users. Currently, luminous keyboards have been launched on the market. In addition to being visually attractive to users, they can also be used at night or in places with insufficient lighting. It is known that luminous keyboards use low-brightness LEDs to illuminate each square key, so the following problems will arise: 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 light around the keycap is inconsistent; and 3) The overall lighting of a single key and multiple keys is inconsistent.

One of the purposes of the present invention is to provide a luminous keyboard, backlight module and light panel that can improve the consistency of overall luminescence to solve the above-mentioned problems.

According to one embodiment, the present invention provides a backlight module for illuminating at least one keycap, and the backlight module includes a lamp panel, a light guide plate, a shading sheet, and a protruding structure. The lamp panel includes two non-intersecting conductors, a plurality of microstructure areas, and at least one light-emitting unit, the light-emitting unit is connected between the two non-intersecting conductors, and the plurality of microstructure areas and the two non-intersecting conductors do not overlap. The light guide plate is disposed on the lamp panel; the shading sheet is disposed on the light guide plate. The protruding structure is formed on the shading sheet and protrudes toward the lamp panel, the protruding structure is located between the plurality of microstructure areas, and the protruding structure diffuses the light of the light-emitting unit to enter the light guide plate for horizontal transmission. In a derivative example, in a derivative example, the lamp panel further includes a first reflective layer surrounding the light-emitting unit and the protruding structure. In a derivative example, the light guide plate has a light guide hole for accommodating the light-emitting unit, and the first reflective layer is at least partially located in the light guide hole. In a derivative example, the first reflective layer has a reflective layer hole, and the first reflective layer is at least partially located between the reflective layer hole and the light guide hole. In a derivative example, the light-shielding sheet includes an inner reflective area overlapping a protruding structure and a first reflective layer. In a derivative example, the backlight module further includes a glue layer at least partially surrounding the protruding structure. In a derivative example, the light-emitting unit includes at least three grains to provide at least three colors of light, and the three grains are arranged in succession with their short sides facing each other. In a derivative example, the protruding structure is located between two non-intersecting wires. In a derivative example, a plurality of microstructure areas include a pair of inner microstructure areas spaced from each other, and the pair of inner microstructure areas are located on opposite sides of the protruding structure. In a derivative example, the two non-intersecting conductors include two main conductors spaced apart from each other. In a derivative example, the plurality of microstructure regions include a pair of inner microstructure regions spaced apart from each other and located between the two main conductors. In a derivative example, the plurality of microstructure regions include a pair of outer microstructure regions spaced apart from each other and located outside the two main conductors. In a derivative example, the light panel has two sub-conductors electrically connected to the pair of main conductors, and the plurality of microstructure regions include a pair of inner microstructure regions spaced apart from each other and located on opposite sides of the two sub-conductors.

According to another embodiment, the present invention provides a luminous keyboard, comprising at least two adjacent key caps; and a backlight module is located below the at least two adjacent key caps. The backlight module comprises a shading sheet, a light board and at least three protruding structures. The shading sheet has at least two light emitting areas corresponding to at least two adjacent key caps. The light board has at least two light emitting units corresponding to at least two light emitting areas respectively. At least two protruding structures are respectively formed in at least two light emitting areas of the shading sheet and protrude toward the light board respectively, and the at least two protruding structures diffuse the local light of at least two light emitting units respectively. In a derivative example, the light board has a microstructure area located between at least two protruding structures, and the microstructure area spans the gap between at least two adjacent key caps. In a derivative example, the lamp panel has a pair of non-intersecting wires spanning under two adjacent keycaps, and at least two protruding structures are located between the pair of non-intersecting wires.

According to another embodiment, the present invention provides a backlight module including at least three phase neighboring key caps and the backlight module is located below the at least three phase neighboring key caps. The backlight module includes a shading sheet, a lamp board and at least three protruding structures. The shading sheet allows light to pass through and illuminate the at least three phase neighboring key caps. The lamp board has at least three light-emitting units corresponding to the at least three phase neighboring key caps. The at least three protruding structures are respectively formed on the shading sheet and protrude toward the lamp board, and the at least three protruding structures diffuse the local light of the at least three light-emitting units. The backlight module has a plate hole and at least one microstructure area surrounding the plate hole, and the at least one microstructure area is located between the plate hole and the at least three protruding structures in a top view. In a derivative example, the plate hole and at least one microstructure area at least partially overlap a gap between at least three adjacent keycaps. In a derivative example, the backlight module further includes a glue-free area between the plate hole and the glue layer. In a derivative example, the backlight module further includes a glue layer surrounding the plate hole, and at least one microstructure area is located between the glue layer and at least three protruding structures.

Based on the backlight module provided by each embodiment of the present invention, in a derivative example, the light board has a pair of welding pads connected to the light-emitting unit, each of the pair of welding pads has at least one hollow area overlapping protruding structure, and at least one hollow area requires at least two divergent multiple branch lines to define the concave portion of at least one hollow area. In a derivative example, at least one of the multiple branch lines of the pair of welding pads has an exposed portion that can reflect light. In a derivative example, the multiple branch lines of the pair of welding pads constitute a pair of parallel flat edges, and the short side of the light-emitting unit is smaller than the width of the pair of flat edges.

In summary, the present invention forms a protruding structure between two non-intersecting conductors or multiple microstructure areas, and the position of the protruding structure corresponds to the position of the light-emitting unit, thereby increasing the amount of light emitted by the light-emitting unit entering the light guide plate, and using the specially configured microstructure area on the lamp board to recycle light or assist light emission, thereby improving the consistency of overall lighting.

In addition, each embodiment of the present invention solves the connection stability problem of the light-emitting unit and the problem of excessive light concentration in the vicinity of the light-emitting unit. In addition to using a solder pad with a hollow area to ensure that the light-emitting unit can still be connected smoothly when the component is offset, the solder pad and its hollow area are further used to form a light homogenization design of the first light homogenization area with the first reflective layer; in addition, the light board is matched with the inner microstructure area of the second light homogenization area, the glue layer and the glue-free area of the third light homogenization area, and the present invention provides different light homogenization solutions for different blocks along the light path from the light-emitting unit to the outside, and can achieve a high degree of homogenization in both a single key and the entire keyboard.

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

LKB: Luminous keyboard

BLM: Backlight module

KS, KS1, KS2, KS3: Buttons

KCC: Keycaps

KC0: Inner light-transmitting area

KC1: External light-transmitting area

KC2: opaque area

SSR: Support device

MEM: Circuit board

SUP: bottom plate

LCB: Light Board

LGP: Light Guide Plate

SS: Shade film

LT,HT,STa,STb: conductor wire

LED: light emitting unit

RL1: First reflection layer

RL2: Second reflection layer

RL0: internal reflection area

RLF: External Reflection Zone

RLH: Reflection Layer Hole

Mh: Copper mesh

ML:Mask layer

ML0: Inner mask area

MLH: Mask hole

PL: Protective layer

MS,LMS: microstructure area

IMS: Internal Microstructure Zone

OMS: External microstructure zone

CMS: nuclear microstructure region

L0: light guide hole

Sc: Inner hole

Sr0: Annular rib

Sr1: Bridge rib

Sf: Support frame

SUPH: Peripheral hole

BP,DP,SP: protruding structure

IP: Groove

Gx, Gy: Gap

BH: Plate hole

MP: Masking Department

HA: Porous gel

HC: Porosity

Ah, Ah1, Ah2: glue layer

AP:Colloid gap

Br: branch line

CL: Conductive layer

CA: glue-free area

Dt: conductor direction

Dn: Normal direction (conductor)

FP: solder pad

FG: Pad gap

Ha,Hb: hollow area

IE: Intersection point

RL1i: Inner ring part

RLH1: Reflection layer hole

Figure 1 is a schematic diagram of a luminous keyboard according to an embodiment of the present invention.

Figure 2 is a partial top view of the illuminated keyboard in Figure 1.

Figure 3 is a partial exploded view of the illuminated keyboard in Figure 1.

Figure 4 is a partial cross-sectional view of the luminous keyboard in Figure 1.

Figure 5 is a partial top view of a luminous keyboard according to another embodiment of the present invention.

Figure 6 is a partial cross-sectional view of the luminous keyboard in Figure 5.

Figure 7 is a partial cross-sectional view of a luminous keyboard according to another embodiment of the present invention.

Figure 8 is a partial cross-sectional view of a luminous keyboard according to another embodiment of the present invention.

Figure 9 is a partial cross-sectional view of a luminous keyboard according to another embodiment of the present invention.

Figure 10 is another partial top view of the luminous keyboard in Figure 1.

Figure 11 is another partial top view of the luminous keyboard in Figure 1.

Figure 12A is a top view schematic diagram of the end-to-end connection between the (sub) wires of the light board, the pads and the light-emitting unit in another embodiment of the present invention.

Figure 12B is a partially enlarged schematic diagram of the embodiment of Figure 12A.

Figure 12C is a top view schematic diagram of the side connection of the embodiment of Figure 12A.

Figures 13A to 13F are respectively top-view schematic diagrams of the connection structure between the (sub) conductors of the light board and the two pads and the light-emitting unit in different embodiments of the present invention.

Figure 14A is a partial top view schematic diagram of the optical structure of the backlight module in the area around the light-emitting unit in another embodiment of the present invention.

Figure 14B is a partial cross-sectional schematic diagram of the backlight module of the embodiment of Figure 14A.

Figure 14C is a partial top view schematic diagram of the optical structure of the backlight module in the area around the light-emitting unit in another embodiment of the present invention.

Figure 14D is a partial top view schematic diagram of the optical structure of the backlight module of the derivative embodiment of Figure 14A of the present invention.

The use of low-power light-emitting units such as Mini LED or Micro LED can reduce power consumption, reduce the total heat generated by the backlight module, and reduce the overall thickness of the backlight module, which helps to further thin the overall illuminated keyboard. However, the highly limited luminous range of Mini LED or Micro LED brings great challenges to the luminous uniformity of the single key and the entire keyboard. The embodiment of the present invention first focuses on how to achieve a large proportion of the light from the light-emitting unit entering the light guide plate for horizontal transmission, and how to effectively recycle the light that passes through the light guide plate during the horizontal transmission process into the light guide plate for reuse.

Please refer to Figure 1, which is a schematic diagram of a luminous keyboard LKB according to an embodiment of the present invention.

As shown in FIG. 1 , the luminous keyboard LKB includes a backlight module BLM and a plurality of keys KS. A base plate SUP is disposed on the backlight module BLM, and the plurality of keys KS are disposed on the base plate SUP. Generally speaking, the plurality of keys KS may include square keys and multiple keys (e.g., blank keys). It should be noted that the number, size, and arrangement of the keys KS may be determined according to actual applications and are not limited to the embodiments shown in the figure.

The backlight module BLM includes a lamp board LCB, a light guide plate LGP and a light shielding sheet SS. The light guide plate LGP is disposed on the lamp board LCB, and the light shielding sheet SS is disposed on the light guide plate LGP. Each key KS on the light-emitting keyboard LKB corresponds to at least one light-emitting unit (e.g., light-emitting diode) on the lamp board LCB of the backlight module BLM.

Please refer to Figures 2 to 4. Figure 2 is a partial top view of the luminous keyboard LKB in Figure 1, Figure 3 is a partial exploded view of the luminous keyboard LKB in Figure 1, and Figure 4 is a partial cross-sectional view of the luminous keyboard LKB in Figure 1.

As shown in FIGS. 2 to 4, the light board LCB includes two non-intersecting wires LT and HT, another two non-intersecting wires STa and STb, a light-emitting unit LED, a first reflective layer RL1, and a plurality of microstructure regions MS. The light board LCB can be a light-emitting circuit board. The light-emitting unit LED is connected between the two non-intersecting wires STa and STb, and the light-emitting unit LED is connected between the two non-intersecting wires LT and HT via the two non-intersecting wires STa and STb. In this embodiment, the wires LT and HT are the main driving circuits of the light-emitting unit LED, and the wires STa and STb are the sub-driving circuits of the light-emitting unit LED, wherein the wire LT can be a low potential wire, and the wire HT can be a high potential wire. The light-emitting unit LED can be a white light-emitting diode or a combination of red, green and blue light-emitting diodes, depending on the actual application. Generally speaking, the wires LT and HT are main wires with larger cross-sectional areas, which can cross multiple keys KS. The wires LT and HT do not intersect at least within the range of a single key KS, and may also not intersect within adjacent multiple keys KS and a larger continuous area covering the key gaps. The pair of wires STa and STb set within each single key KS are sub-wires with smaller cross-sectional areas. Although they may be located on the same straight line, the ends of the wires STa and STb are respectively connected to the two electrodes of the light-emitting unit LED, so the wires STa and STb do not overlap.

The first reflective layer RL1 is disposed on two non-intersecting conductors LT, HT and another two non-intersecting conductors STa, STb. A plurality of microstructure regions MS are formed on the first reflective layer RL1. In the present embodiment, the microstructure region MS may be a concave-convex structure formed on the first reflective layer RL1. For example, the light board LCB may be formed of a flexible circuit board, and a copper mesh (such as the component labeled Mh in FIG. 14B ) is often used to enhance the supporting strength of the circuit board. The first reflective layer RL1 may be formed by spraying reflective paint or coating a reflective film on the surface of the flexible circuit board (including the copper mesh surface). The grid structure of the copper mesh will form regular concave points (grid points) and convex areas (grid lines) on the first reflective layer RL1. These concave points and convex areas have the function of reflection points, which can reflect light back to the light guide plate LGP. In fact, the copper wire area (wires LT, HT, STa, STb) can also become a protruding linear reflection area. In principle, the copper mesh does not overlap with the wires LT and HT on the flexible circuit board, nor is it electrically connected to the wires STa and STb. However, in application, the copper mesh has a radio frequency interference shielding effect, so the copper mesh may be connected to the ground of the drive line. However, in practice, not any reflection layer covering the copper mesh and the line can produce a concave and convex reflection structure. If the first reflective layer RL1 is an independent thin film element, the thickness of the first reflective layer RL1 must be thin enough, for example, lower than the thickness of the copper foil substrate (including the adjacent flat copper mesh and copper wire area), and the first reflective layer RL1 needs to have a high degree of plasticity to form a concave-convex microstructure in the copper mesh and copper wire area when covering the copper foil substrate. If the first reflective layer RL1 is formed by ink coating, for example, the coating thickness, ink concentration, coating area control, etc. must be strictly controlled, otherwise the original hollow areas of the copper foil substrate are easily filled with ink flow, reducing the depth of the reflective microstructure and the reflective diffusion effect.

In addition, even if the circuit of the light board LCB is not a copper foil substrate, there is no thick copper circuit, and there is no copper mesh to enhance the structural strength of the light board LCB, a microstructure with a diffusion effect can still be formed on the first reflective layer RL1. For example, printing micro-dot ink on the first reflective layer RL1 forms a concave area/convex area as a microstructure area MS; or, using ink with larger reflective particles, when spraying or printing the first reflective layer RL1, a concave area/convex area is formed as a microstructure area MS; or, if the first reflective layer RL1 is a layer of reflective film, the reflective film surface can be selected as long as it has reflective particles with medium to low flatness and has an uneven reflective surface, which can be used as the microstructure area MS.

In this embodiment, within the scope of a single key KS, the plurality of microstructure regions MS include two inner microstructure regions IMS and two outer microstructure regions OMS, wherein the two inner microstructure regions IMS are located between the two non-intersecting wires LT and HT, and the two outer microstructure regions OMS are located outside the two non-intersecting wires LT and HT. The patterns of the two inner microstructure regions IMS may be different from the patterns of the two outer microstructure regions OMS, but are not limited thereto. The light-emitting unit LED is located between the plurality of microstructure regions MS, that is, the light-emitting unit LED is located between the two inner microstructure regions IMS and also between the two outer microstructure regions OMS.

In this embodiment, the conductors STa and STb divide two inner microstructure regions IMS, so the conductors STa and STb are also located between the two inner microstructure regions IMS; similarly, the conductors LT and HT divide an outer microstructure region OMS and two inner microstructure regions IMS, respectively, so it can also be said that the conductors LT and HT are located between an outer microstructure region OMS and two inner microstructure regions IMS, respectively. In some embodiments, the aforementioned plurality of microstructure regions MS, whether the outer microstructure region OMS or the inner microstructure region IMS, do not overlap the conductors LT and HT, nor do they overlap the conductors STa and STb; for example, this is the case when the circuit of the lamp panel LCB is copper wire matched with copper mesh. If the microstructure area MS on the first reflective layer RL1 is only surface treated and not formed from the copper mesh or other substrate below, multiple microstructure areas MS/OMS/IMS may overlap the wires LT, HT, or overlap the wires STa, STb. The light guide plate LGP has a light guide hole L0, and the light-emitting unit LED is located in the light guide hole L0. The top surface and/or bottom surface of the light guide plate LGP near the light guide hole L0 may have an adhesive surrounding the light guide hole L0 to respectively adhere the shading sheet SS and/or the lamp board LCB. In addition, the light guide plate LGP also has multiple microstructure areas LMS corresponding to the positions of the inner hole Sc and the peripheral hole SUPH of the bottom plate SUP, so as to guide the light transmitted in the light guide plate LGP to emit light upward. Below the orthographic projection of the peripheral hole SUPH of the base plate SUP, the microstructure area LMS of the light guide plate LGP can at least partially overlap with the multiple microstructure areas MS of the first reflective layer RL1 of the lamp board LCB, and in particular can increase the light output effect through the inner hole Sc and the peripheral hole SUPH, and enhance the brightness of the corner symbol (external light-transmitting area KC1) of the key cap KCC. The inner microstructure area IMS on the first reflective layer RL1 of the light board LCB near the light-emitting unit LED can be used as an optical adjustment method. When the light output near the light-emitting unit LED is excessively weakened, for example, the inner mask area ML0 of the mask layer ML of the light-shielding sheet SS is too large, or the transmittance of one of the inner reflective areas RL0 of the second reflective layer RL2 is too low, the inner microstructure area IMS on the first reflective layer RL1 of the light board LCB near the light-emitting unit LED can enhance the light output effect of the light-transmitting area KC0 passing through the inner hole Sc or the key cap KCC.

A better way to optimize the configuration of the aforementioned multiple microstructure areas MS/OMS/IMS is to set the wires STa, STb, LT, and HT to overlap with any rib area or frame area (such as annular rib Sr0, bridge rib Sr1, support frame Sf) of the base plate SUP as much as possible. In this way, the aforementioned multiple microstructure areas MS/OMS/IMS will be able to correspond to the microstructure area LMS of the light guide plate LGP, and also to the peripheral hole SUPH or inner hole Sc of the base plate SUP, and even to the inner light-transmitting area KC0 and the outer light-transmitting area KC1 of the key cap KCC. In addition, multiple microstructure areas MS/OMS/IMS may overlap the annular rib Sr0, bridge rib Sr1 or support frame Sf of the bottom plate SUP. Although these positions cannot emit light, the microstructure area MS/OMS/IMS can help guide the light that escapes from the light guide plate LGP into the light guide plate LGP for recycling, which is helpful for the subsequent light emission effect of another key KS that is further outside or even adjacent. Of course, the aforementioned microstructure area MS/OMS/IMS can also overlap with the second reflective layer RL2 of the light shielding sheet SS, including overlapping with the inner reflective area RL0 and the outer frame of the second reflective layer RL2, which is helpful for light recycling to the light guide plate LGP.

The shading sheet SS is disposed above the plurality of microstructure regions MS. The shading sheet SS plate includes a mask layer ML, a second reflective layer RL2, and a protective layer PL, wherein the mask layer ML, the second reflective layer RL2, and the protective layer PL can be stacked on each other in various ways. For example, any one of the mask layer ML, the second reflective layer RL2, and the protective layer PL can be stacked on the top, the middle, or the bottom to form the shading sheet SS. The mask layer ML is opaque. The second reflective layer RL2 can have both reflective and translucent properties, that is, the second reflective layer RL2 can reflect part of the light and allow part of the light to pass through. The mask layer ML can be black paint, and the second reflective layer RL2 can be white paint, but not limited thereto. In this embodiment, the mask layer ML has a mask hole MLH and an inner mask area ML0 located in the mask hole MLH, and the second reflective layer RL2 has a reflective layer hole RLH and an inner reflective area RL0 located in the reflective layer hole RLH. The mask hole MLH can be larger, equal to or smaller than the reflective layer hole RLH, and the inner mask area ML0 can be larger, equal to or smaller than the inner reflective area RL0, depending on the desired luminous effect. The inner mask area ML0 and the inner reflective area RL0 are located above the light-emitting unit LED. In this embodiment, the inner mask area ML0 and/or the inner reflective area RL0 above the light-emitting unit LED are at least partially projected between two non-intersecting conductors LT, HT or STa, STb.

Each key KS includes a portion of the bottom plate SUP. In the present embodiment, the bottom plate SUP has an inner hole Sc, an annular rib Sr0, a plurality of bridging ribs Sr1, and a support frame Sf, wherein the annular rib Sr0 surrounds the inner hole Sc, and the plurality of bridging ribs Sr1 connect the annular rib Sr0 and the support frame Sf. In addition, there are a plurality of peripheral holes SUPH between the bridging rib Sr1, the annular rib Sr0, and the support frame Sf. In the present embodiment, the two inner microstructure regions IMS at least partially overlap with the projections of the inner hole Sc, the annular rib Sr0, the plurality of bridging ribs Sr1, and/or the support frame Sf. In addition, the two outer microstructure regions OMS at least partially overlap with the projections of the annular ribs Sr0, the plurality of bridging ribs Sr1 and/or the support frame Sf.

The key KS includes a key cap KCC, a support device SSR, a circuit board MEM and a bottom plate SUP. The key cap KCC is arranged relative to the bottom plate SUP. The key cap KCC has an inner light-transmitting area KC0 and a plurality of outer light-transmitting areas KC1, wherein the inner light-transmitting area KC0 and the outer light-transmitting area KC1 are surrounded by a non-light-transmitting area KC2. The positions of the inner light-transmitting area KC0 and the outer light-transmitting area KC1 correspond to the positions of the inner hole Sc and the peripheral hole SUPH of the bottom plate SUP, respectively, so that the light emitted by the light-emitting unit LED can be projected from the inner light-transmitting area KC0 and the outer light-transmitting area KC1 of the key cap KCC through the light guide plate LGP, the light shielding sheet SS, the inner hole Sc and the peripheral hole SUPH of the bottom plate SUP. The support device SSR is arranged between the key cap KCC and the bottom plate SUP. When the key cap KCC is pressed, the key cap KCC moves vertically toward the base plate SUP along with the support device SSR. In addition, a reset member (not shown in the figure) is provided between the key cap KCC and the base plate SUP, such as a rubber dome, but not limited thereto. The circuit board MEM has a switch corresponding to the key KS, such as a membrane switch or other trigger switch.

From the top view, the light-emitting unit LED, the light-guiding hole L0, the internal reflection area RL0, the internal mask area ML0, the inner hole Sc, the inner light-transmitting area KC0 and the adhesive around the light-guiding hole L0 can be located between the two non-intersecting conductors LT, HT and/or STa, STb.

From the top view, the light-emitting unit LED, the light-guiding hole L0, the internal reflection area RL0, the internal mask area ML0, the inner hole Sc, the inner light-transmitting area KC0, and the adhesive around the light-guiding hole L0 can be located between the two inner microstructure areas IMS.

As shown in FIG. 4 , the backlight module BLM further includes a protruding structure BP, wherein the position of the protruding structure BP corresponds to the position of the light-emitting unit LED, and the protruding structure BP is located between two non-intersecting wires LT and HT. In addition, the protruding structure BP is also located between a plurality of microstructure regions MS, that is, the protruding structure BP is located between two inner microstructure regions IMS and between two outer microstructure regions OMS. In this embodiment, the protruding structure BP is formed on the lamp board LCB, and the protruding structure BP forms a groove IP to accommodate the light-emitting unit LED, so that the upper surface of the light-emitting unit LED is flush with or lower than the upper surface of the light guide plate LGP and higher than the lower surface of the light guide plate LGP. Since the shading sheet SS is arranged on the light guide plate LGP, the upper surface of the light-emitting unit LED will also be flush with or lower than the lower surface of the shading sheet SS, so that the shading sheet SS can remain flat and will not be pushed by the light-emitting unit LED and partially enter the inner hole Sc of the bottom plate SUP. In this way, the amount of light emitted by the light-emitting unit LED entering the light guide plate LGP can be increased, thereby improving the consistency of the overall lighting. Furthermore, the circuit board MEM can have a switch arranged corresponding to the inner hole Sc of the bottom plate SUP, so that the switch can partially enter the inner hole Sc of the bottom plate SUP without interfering with the SS shading sheet and the light-emitting unit LED below it.

Please refer to Figure 5 and Figure 6. Figure 5 is a partial top view of the luminous keyboard LKB according to another embodiment of the present invention, and Figure 6 is a partial cross-sectional view of the luminous keyboard LKB in Figure 5.

As shown in Figures 5 and 6, the base plate SUP may not have the above-mentioned inner hole Sc. At this time, the shading sheet SS remains flat and will not be pushed by the light-emitting unit LED. When the base plate SUP does not have the inner hole Sc, the key cap KCC may not have the inner light-transmitting area KC0. However, if the key cap KCC has an inner light-transmitting area KC0, the peripheral holes SUPH around the central area of the key cap KCC can be used to emit light, so that the light is projected from the inner light-transmitting area KC0 without the inner hole Sc. In this embodiment, the two non-intersecting wires HT and LT may overlap with the projection of at least one of the at least one outer light-transmitting area KC1. As long as the two non-intersecting wires HT and LT meet at least one of the following three conditions, the wires HT and LT will not affect the luminescence of the light-transmitting area KC1 outside the key cap KCC. Condition 1: The projections of the two non-intersecting conductors HT, LT and the annular ribs Sr0, bridge ribs Sr1 and/or support frame Sf of the bottom plate SUP overlap. Condition 2: The projections of the two non-intersecting conductors HT, LT and the mask layer ML and/or the second reflective layer RL2 of the light shielding sheet SS overlap. Condition 3: The projections of the two non-intersecting conductors HT, LT and the opaque area KC2 of the key cap KCC overlap.

Please refer to Figure 7, which is a partial cross-sectional view of the luminous keyboard LKB according to another embodiment of the present invention.

As shown in FIG. 7 , the protruding structure SP of the backlight module BLM can be formed on the shading sheet SS, wherein the light-emitting unit LED is located below the protruding structure SP. The position of the protruding structure SP corresponds to the position of the light-emitting unit LED, and the protruding structure SP is located between two non-intersecting conductors LT and HT. In addition, the protruding structure SP is also located between a plurality of microstructure regions MS, that is, the protruding structure SP is located between two inner microstructure regions IMS and also between two outer microstructure regions OMS. In the present embodiment, the protruding structure SP may be lower than or slightly enter the inner hole Sc of the bottom plate SUP, and the upper surface of the light-emitting unit LED is flush with or lower than the upper surface of the light guide plate LGP or the lower surface of the shading sheet SS. It should be noted that the protruding structure SP can be pressed back so that the top of the shading sheet SS below the bottom plate SUP has a flat surface. In FIG. 7, the effect of the protruding structure SP formed on the light shielding sheet SS may come from the fact that the second reflective layer RL2 on the light shielding sheet SS above the light emitting unit LED is formed with a curved surface or a slope due to the protruding structure SP; because the reflection angle provided by the straight second reflective layer RL2 is small, it is difficult to guide the upward irradiated light to enter directly from the light guide hole L0 hole wall of the light guide plate LGP.

Please refer to Figure 8, which is a partial cross-sectional view of the luminous keyboard LKB according to another embodiment of the present invention.

As shown in Figure 8, the upper surface of the light-emitting unit LED can be higher than the upper surface of the light guide plate LGP and lower than the lower surface of the light shielding sheet SS, that is, the upper surface of the light-emitting unit LED can be located between the upper surface of the light guide plate LGP and the lower surface of the light shielding sheet SS. If necessary, the light-emitting unit LED can also exceed the upper surface of the LGP. For example, the protrusion structure SP can bulge upward to allow the thickness of the light shielding sheet SS itself and the thickness of the upper and lower adhesive layers of the light shielding sheet SS to provide space for accommodating the light-emitting unit LED; at this time, the upper surface of the light-emitting unit LED will be located between the lower surface of the bottom plate SUP and the upper surface of the LGP. Thus, when the upper surface of the light-emitting unit LED is higher than the upper surface of the light guide plate LGP, the protrusion structure SP can provide space for accommodating the light-emitting unit LED to prevent the light-emitting unit LED from interfering with the light shielding sheet SS.

Please refer to Figure 9, which is a partial cross-sectional view of the luminous keyboard LKB according to another embodiment of the present invention.

As shown in FIG. 9, the light-emitting keyboard LKB may not include the protruding structure BP shown in FIG. 4 or the protruding structure SP shown in FIG. 7. In this embodiment, the upper surface of the light-emitting unit LED is flush with or lower than the upper surface of the light guide plate LGP and higher than the lower surface of the light guide plate LGP. In this way, the amount of light emitted by the light-emitting unit LED entering the light guide plate LGP can be increased, thereby improving the consistency of the overall lighting.

Please refer to Figure 10, which is another partial top view of the luminous keyboard LKB in Figure 1.

As shown in FIG. 10 , the plurality of microstructure regions OMS, IMS at least partially overlap the projection of the gaps Gx, Gy between any two adjacent keys KS1, KS2, KS3. Three adjacent keys KS1, KS2, KS3 may have three adjacent outer microstructure regions OMS, wherein the three adjacent outer microstructure regions OMS are combined together in the X and Y directions. Two outer microstructure regions OMS outside two non-intersecting wires of the light board LCB disposed under a key KS may have the same pattern, and may have the same size, the same shape, and the same distance (outside the wires) in two identical regions. Within the projection range of a single key KS (e.g., a square key), the two outer microstructure regions OMS may have different patterns defined by the key KS. For two adjacent keys KS in the Y direction, the two adjacent outer microstructure regions OMS may have different patterns defined by the two adjacent keys KS.

Please refer to Figure 11, which is another partial top view of the luminous keyboard LKB in Figure 1.

As shown in FIG. 11 , a plate hole BH may be provided on the light board LCB, wherein the plate hole BH is used for fixing or heat dissipation. A mask portion MP may be provided on the light board LCB, wherein the mask portion MP surrounds the plate hole BH and is used to shield and absorb light to prevent light from leaking from the plate hole BH. In practice, the mask portion MP may be a light-absorbing or opaque substrate of the light board LCB, that is, the first reflective layer RL1, the circuit layer, and the insulating layer (if necessary) above the substrate of the light board LCB are all provided with holes larger than the plate hole BH, so as to expose the mask portion MP surrounding the plate hole BH. Another practical approach is to coat the upper surface of the first reflective layer RL1 of the lamp board LCB with a mask portion MP surrounding the plate hole BH. In this case, the hole size of the first reflective layer RL1 is similar to the plate hole BH. The plate hole BH and the mask portion MP on the lamp board LCB may correspond to the plate hole and the mask portion on the light shielding sheet SS (not shown in the figure). The porous glue HA on the lamp board LCB may be disposed on the mask portion MP and surround the plate hole BH. The pore HC does not overlap with the outer microstructure area OMS or any microstructure. The pore HC without the first reflective layer RL1 may be defined between the first reflective layer RL1 and the plate hole BH. The pore HC without glue may be defined between the porous glue HA and the plate hole BH. The inner microstructure region IMS (between two non-intersecting wires HT, LT and/or between STa, STb) does not overlap with the plate hole BH, the porous gel HA and/or the pore HC. A plurality of adjacent keys KS1, KS2, KS3 in the X and/or Y directions may have adjacent outer microstructure regions OMS that jointly surround the mask portion MP, the plate hole BH, the porous gel HA and/or the pore HC. The mask portion MP, the plate hole BH, the porous gel HA and/or the pore HC are located between the wires HT, LT corresponding to the key KS1 and the wires HT, LT corresponding to the keys KS2, KS3. Furthermore, the mask MP, the plate hole BH, the porous gel HA and/or the pore HC may be located between the wire LT corresponding to the key KS1 and the wire HT corresponding to the keys KS2 and KS3. It should be noted that the mask MP, the porous gel HA and the pore HC are schematically shown at the same position in Figure 11. However, the definitions of the mask MP, the porous gel HA and the pore HC can be clearly understood based on the above description.

In summary, the present invention makes the multiple microstructure areas on the lamp panel non-overlapping with the two non-intersecting wires, so that the specially configured microstructure areas on the lamp panel can be used to recycle light or assist light emission, thereby improving the consistency of the overall light emission. In addition, although the technical solution of the present invention is based on solving the application problem of low-power light-emitting units, the present invention is also applicable to the application of medium and high-power light-emitting units in backlight modules.

Furthermore, since the low-power light-emitting unit is too small, when it is installed on the light board, the melting of the solder paste can easily cause the position of the light-emitting unit to shift, resulting in the failure of smooth electrical connection between the light-emitting unit and the light board. The following embodiments of the present invention will introduce several technical solutions through a special solder pad design

Please refer to Figures 12A to 12C. Figure 12A is a top view schematic diagram of the end-to-end connection between the (sub) wires of the lamp panel and the pads and the light-emitting unit of another embodiment of the present invention. Figure 12B is a partial enlarged schematic diagram of the embodiment of Figure 12A. Figure 12C is a top view schematic diagram of the side connection of the embodiment of Figure 12A.

In FIG. 12A and FIG. 12B, two (sub) conductors STa/STb (see the aforementioned embodiments and FIG. 3, FIG. 8, and FIG. 9) extend respectively along the conductor direction Dt, and the two (sub) conductors STa/STb have a pad FP at their ends respectively, and a pad gap FG is provided between the two pads FP. Each pad FP can be directly formed integrally with the circuit of the light board LCB (such as the conductors HT/LT/STa/STb) through printed conductive wires, or can be formed integrally with the circuit of the light board LCB through a copper foil substrate etching process; however, each pad FP can also be secondary molded, or made of a different material from the circuit of the light board LCB. The two pads FP have an intersection point IE as the end, and the distance between the two intersection points IE is also the shortest distance between the two pads FP. The gap FG between the two intersection points IE is smaller than the long side of the light-emitting unit LED, for example, the gap between the two intersection points IE is close to 0.5 times the long side of the light-emitting unit LED or shorter. The intersection point IE can actually be the end point of the two adjacent ends of the pads FP, or the geometric center point of the two adjacent ends of the pads FP. The two pads FP of the present invention each have at least two branch lines Br (branch) extending outward from the intersection point IE, thereby defining at least one hollow area Ha/Hb. In Figure 12A/12B, each pad FP has three branch lines Br, of which the middle branch line Br extends straight outward from the intersection point IE to connect to the (sub) conductor STa/STb, and the remaining two left and right branch lines Br extend outward from the intersection point IE in an L-shaped path and also connect to the (sub) conductor STa/STb. The three branch lines Br of each pad FP jointly define two hollow areas Ha/Hb, and the boundary (bbrder) of the two hollow areas Ha/Hb extends along the middle branch line Br. Structurally, in order to form a concave structure as the hollow area Ha or Hb, at least two divergent branch lines Br are required to define the concave part of the hollow area Ha or Hb.

The positive and negative electrodes of the light-emitting unit LED are electrically connected to the two pads FP through a conductive layer CL, and the connection position is located at the two intersection points IE or their vicinity. The conductive layer CL is implemented, for example, with solder paste or its substitute material. The thickness and area of the conductive layer CL will affect the degree of deviation of the light-emitting unit LED during component bonding. Therefore, the printing of the conductive layer CL must be concentrated as much as possible at the intersection point IE of the two pads FP and extend to a limited extent along the branch line Br. The connection direction of the positive and negative electrodes of the light-emitting unit LED, or the long side of the light-emitting unit LED, is parallel to the wire direction Dt. The (flat side) width of the two pads FP can be set to be at least 0.8-1.5 times the short side of the LED. If the light-emitting unit LED is offset along the normal direction Dn of the wire STa/STb or along the short side of the light-emitting unit LED, the positive and negative electrodes of the light-emitting unit LED still have a considerable chance of ensuring electrical connection to the two pads FP. If the light-emitting unit LED is offset along the wire direction of the wire STa/STb or along the long side of the light-emitting unit LED, the offset must exceed 0.5 times the long side length of the light-emitting unit LED, so that the light-emitting unit LED cannot be electrically connected to the two pads FP at the same time. Regardless of how the light-emitting unit LED is offset, the light-emitting unit LED overlaps at least partially with one of the hollow areas Ha or Hb of one of the pads FP, for example, a corner or one side of the light-emitting unit LED overlaps with at least one hollow area Ha or Hb. The overall size of the two pads FP (including the hollow area Ha or Hb, the branch line Br and the pad gap FG) can be set to be at least 1.2 times larger than the light-emitting unit LED; or, the two pads FP each have at least one branch line Br forming a pair of parallel flat edges, and the short side of the light-emitting unit LED is preferably smaller than the width of the pair of flat edges of the two pads FP. In this way, even in the case of maximum offset, the light-emitting unit LED (either side) does not exceed the outermost periphery of any pad FP. In an ideal situation with no component offset, all four corners of the light-emitting unit LED can overlap with the hollow area Ha or Hb respectively. However, under the premise of highly stable process parameters, the flat side of the pad FP may be less than or equal to the short side of the light-emitting unit LED; even so, at least the light-emitting unit LED (such as a side or corner) must be able to overlap the hollow area Ha/Hb to maintain the basic offset prevention mechanism.

The first significance of the hollow area Ha/Hb is to provide at least two branch lines Br for each solder pad FP to connect the positive/negative electrodes of the light-emitting unit LED. Secondly, the intersection point IE of the intersection of the branch lines Br (or the end of the junction of the two hollow areas Ha/Hb) can be used as the positioning point of the light-emitting unit LED in the automated process. Furthermore, the conductive layer CL tends to flow along the branch line Br when it is melted, and the existence of the hollow area Ha/Hb prevents the conductive layer CL from flowing toward the hollow area Ha/Hb when it is melted to a considerable extent. In addition, the width of each branch line Br can be only 0.5 times or less of the short side of the light-emitting unit LED, so as to limit the range/angle of the melting flow of the conductive layer CL so as not to diffuse, and further limit the angle/path of the deviation of the light-emitting unit LED. In this way, it can be ensured that the light-emitting unit LED will be offset along the branch line Br, thereby improving the yield of the light-emitting unit LED electrically connecting the two pads FP and the two wires STa/STb.

Please refer to Figures 12A to 12C at the same time. In Figures 12A and 12B, the wires STa/STb are end-to-end opposite to each other, and their two hollow areas Ha and two hollow areas Hb are arranged perpendicular to the wire direction Dt. Figure 12C is different. The wires STa/STb are partially overlapped in the perpendicular wire direction Dt and are edge-to-edge opposite to each other, so the positions of the two pads FP are rotated 90 degrees, and the two hollow areas Ha and two hollow areas Hb are arranged along the wire direction Dt. Regardless of end-to-end or edge-to-edge connection, the hollow areas Ha/Hb and branch lines Br of the pad FP can effectively improve the yield of the two pads FP and the two wires STa/STb of the light-emitting unit LED.

Please refer to Figures 13A to 13F, and also to Figures 12A to 12C. Figures 13A to 13F are respectively top views of the connection structure of the (sub) conductors STa/STb of the lamp board LCB and the two pads FP and the light-emitting unit LED in different embodiments of the present invention.

In Figures 12A to 12C, three branch lines Br form a T shape, and each branch line Br is at least partially parallel to the short side and the long side of the light-emitting unit LED, but the present invention is not limited to this. In Figure 13A, each pad FP has only two branch lines Br extending outward obliquely from the intersection IE, and the two branch lines Br of each pad FP are bent at a blunt angle, and finally define a hollow area Ha/Hb with the two conductive wires STa/STb. Although the light-emitting unit LED in FIG. 13A still at least partially overlaps the hollow area Ha and/or Hb, the distance between the two branch lines Br on the same side of different pads FP will become larger and larger when the light-emitting unit LED shifts left and right along the normal direction Dn, so the blunt angle between the two branch lines Br of each pad FP should not be too small, for example, between 150 degrees and 180 degrees, so as to avoid the light-emitting unit LED shifting beyond the width of the two electrodes. A similar but better implementation example is shown in FIG. 13B, which is also a triangular pad FP, and the two angular branch lines Br are formed with flat sides opposite to the flat sides formed by the branch lines Br of another pad FP, so that the problem of the distance between the two branch lines Br on the same side of different pads FP will not occur when the light-emitting unit LED shifts. In addition, the width of the wires STa/STb in FIG. 13B is narrower (e.g., copper wires formed by etching a copper foil substrate, while the width of the wires STa/STb in FIG. 13A is wider (e.g., printed from a metal paste with lower conductivity than the etched copper wire). Both have no direct effect on the electrical connection between the pad FP and the light-emitting unit LED.

In Figure 13C, both pads FP have three branch lines Br, and the configuration is similar to Figures 12A and 12B. The middle branch line Br extends straight outward from the intersection IE to connect to the (sub) wire STa/STb, and the remaining two branch lines Br extend outward from the intersection IE in a U-shaped path and also connect to the (sub) wire STa/STb. The width of the wire STa/STb in Figure 13C is narrower, compared to the width of the wire STa/STb in Figures 12A and 12B. However, as mentioned above, the width of the wire STa/STb has little effect on the electrical connection between the pad FP and the light-emitting unit LED.

In Figure 13D, both pads FP have three branch lines Br, and the configuration is similar to Figure 13C. In Figure 13D, the middle branch line Br extends straight outward from the intersection point IE to connect to the (sub) conductor STa/STb, and the remaining left and right branch lines Br extend outward from the intersection point IE in a U-shaped path and also connect to the (sub) conductor STa/STb. The difference is that the shape of the pad FP in Figure 13D is closer to a semicircle, that is, the left and right branch lines Br in Figure 13D both have arc-shaped guide angles, which corresponds to the more arcs of the light guide hole L0 in the aforementioned Figure 3 or the subsequent Figures 14A to 14D, so that it can better match and increase the amount of light entering the side of the light guide plate LGP. In Figure 13E, although each pad FP has a branch line Br extending outward from the intersection IE to form a flat edge, only the central branch line Br is connected to the (sub) conductor STa/STb. The left and right branch lines Br extend outward from the intersection IE in a straight line path in the normal direction Dn, and do not extend to the (sub) conductor STa/STb or connect to the conductor STa/STb. However, the central branch line Br still defines the hollow area Ha/Hb with the left and right branch lines Br respectively, so that the light-emitting unit LED at least partially overlaps one of the hollow areas Ha/Hb.

The pads FP in FIG. 13F are similar to those in FIG. 13D, but the middle branch line Br is missing. Only the left and right branch lines Br extend outward from the intersection IE in a U-shaped path and connect to the (sub) conductors STa/STb. The two pads FP and their branch lines Br in FIG. 13F also form a pair of parallel flat edges. Each of the two pads FP has only one hollow area Ha/Hb, so that the light-emitting unit LED at least partially overlaps (two short sides) at least one of the hollow areas Ha/Hb. The two short sides of the light-emitting unit LED in FIG. 13F respectively cross the hollow areas Ha/Hb, which is also similar to the triangular pads FP in FIG. 13A and FIG. 13B, but the pads FP and the hollow areas Ha/Hb in FIG. 13F are larger than those in FIG. 13A and FIG. 13B. Furthermore, in FIG. 13A to FIG. 13F, although each pair of pads FP is connected to the light-emitting unit LED in an end-to-end structure, in practice, based on the description of the aforementioned embodiments, the different types of pads FP in FIG. 13A to FIG. 13F of the present invention can be applied to an edge-to-edge lateral connection structure similar to FIG. 12C.

In addition, the area around the low-power light-emitting unit is the area with the highest brightness. Expanding the light reflection angle in this area is the key to increasing the amount of light entering the side of the light guide plate, improving the lateral transmission ratio, and promoting the uniformity of light emission. However, the area around the light-emitting unit is the physical connection area between the light-emitting unit LED and the light board LCB line. How to make the electrical connection structure of the light-emitting unit LED and the light board LCB line simultaneously expand the light reflection angle is a major issue in the design of the light-emitting unit LED electrical connection structure.

Please refer to Figures 14A/14B/14C. Figure 14A is a partial top view schematic diagram of the optical structure of the backlight module in the area around the light-emitting unit in another embodiment of the present invention. Figure 14B is a partial cross-sectional schematic diagram of the backlight module in the embodiment of Figure 14A. Figure 14C is a partial top view schematic diagram of the optical structure of the backlight module in the area around the light-emitting unit in another embodiment of the present invention. Figure 14D is a partial top view schematic diagram of the optical structure of the backlight module of the derivative embodiment of Figure 14A of the present invention.

In FIG. 14A and FIG. 14B, the height difference between the six branch lines Br and the four hollow areas Ha/Hb of the two pads FP produces a concave-convex structure, and the first reflective layer RL1 covering the light-emitting unit LED makes the entire area of each pad FP form a core microstructure area CMS surrounding at least a part of the light-emitting unit LED, wherein the concave area (hollow area Ha/Hb) and the convex area (branch line Br) can play the role of the microstructure area MS respectively. These pads FP and the core microstructure area CMS are located below the reflective area RL0 in the light-shielding sheet SS. Even without the special pad FP and its hollow area Ha/Hb and branch line Br, as long as the first reflective layer RL1 covering the light-emitting unit LED has the above-mentioned concave-convex structure, the core microstructure area CMS can still be formed around the light-emitting unit LED. Therefore, one or more core microstructure areas CMS surrounding the light-emitting unit LED can further reflect and diffuse the light reflected downward by the internal reflection area RL0 of the light shielding sheet SS upward, increase the amount of side light entering the light guide hole L0, and thus improve the lateral transmission ratio and promote the overall light uniformity of the key KS and the light-emitting keyboard LKB.

From the overall structure, with the light-emitting unit LED as the center, the backlight module BLM of the embodiment of the present invention provides a plurality of light-distributing zones for achieving a light-distributing uniform effect, and the plurality of light-distributing zones of the backlight module BLM at least include a first light-distributing zone Z1 and a second light-distributing zone Z2. The first light-distributing zone Z1 surrounds the light-emitting unit LED, and the first light-distributing zone Z1 includes an inner ring portion RL1i of the first reflective layer RL1 and a pair of welding pads FP, which are located on the lamp board LCB for connecting the light-emitting unit LED, and the inner ring portion RL1i of the first reflective layer RL1 at least partially covers the welding pad FP, so that the inner ring portion RL1i of the first reflective layer RL1 reflects and diffuses the light of the light-emitting unit LED. The second light-distributing area Z2 surrounds the first light-distributing area Z1. The second light-distributing area Z2 includes a pair of microstructure areas MS spaced apart from each other and located on the first reflective layer RL1. The pair of microstructure areas MS surround the pair of solder pads FP together. The pair of microstructure areas MS reflect and diffuse the light transmitted by the light-emitting unit LED through the first light-distributing area Z1.

The first light-distributing area Z1 closest to the light-emitting unit LED provides one or more core microstructure areas CMS surrounding the light-emitting unit LED through the two pads FP on the lamp board LCB and the first reflective layer RL1. The combination of the branch lines Br and the hollow areas Ha/Hb makes the first light-distributing area Z1 have a concave-convex structure. Since the pad FP and its core microstructure area CMS overlap at least partially with the internal reflection area RL0 of the light-shielding sheet SS in the Z direction, they can be used to reflect, diffuse and open the angle of the light from the internal reflection area RL0, and incident toward the side of the light guide hole L0. In the first light-homogenizing zone Z1, the reflective layer hole RLH1 may overlap the two pads FP and their hollow areas Ha/Hb, the branch lines Br and the core microstructure area CMS, and the light-guiding hole L0 may also overlap the two pads FP and their hollow areas Ha/Hb, the branch lines Br and the core microstructure area CMS.

Secondly, the second light-evening zone Z2 surrounds the light-emitting unit LED at a further distance, and also surrounds the light-guiding hole L0 and the reflective layer hole RLH1. The second light-evening zone Z2 includes two inner microstructure zones IMS separated by a pair of non-intersecting (sub) conductors STa/STb on the lamp board LCB (refer to FIG. 3, FIG. 10 and FIG. 11 of the aforementioned embodiment together). The two inner microstructure zones IMS are located on the upper surface of the first reflective layer RL1, and together surround at least a portion of the first light-evening zone Z1. Although the two inner microstructure areas IMS may only partially overlap the inner reflection area RL0 of the light shielding sheet SS, and the light directly from the inner reflection area RL0 of S rarely reaches the inner microstructure area IMS, during the lateral transmission of light in the light guide plate LGP, the light with a smaller angle than the critical angle will not be able to continue to be totally reflected inside the light guide plate LGP and pass through the lower surface of the light guide plate LGP. These penetrating light rays can be recovered by the two inner microstructure areas IMS, and then incident on the light guide plate LGP through reflection diffusion to continue lateral transmission.

Furthermore, the backlight module BLM can be provided with a third light-distributing area Z3 between the first light-distributing area Z1 and the second light-distributing area Z2, and the third light-distributing area Z3 can overlap with the first light-distributing area Z1 and/or the second light-distributing area Z2 in the Z direction. The third light-distributing area Z3 mainly includes the glue layer Ah (such as the glue layer Ah1 and/or Ah2 in FIG. 14B ) disposed above the light board LCB in FIG. 14A . Although there is a need to use glue to position the layers of the backlight module BLM, the glue should also be taken into consideration in the optical design; first, the glue layer Ah1/Ah2 is selected to be a light-transmissive glue material with good optical coupling. Although excessive concentration of light around the LED of the light-emitting unit is an original problem of low-brightness light-emitting units, it is also possible to make an overcorrection during implementation, for example, resulting in insufficient light output from the inner light-transmitting area KC0 near the center of the keycap KCC in Figure 3. At this time, the use of the glue layers Ah1/Ah2 can fine-tune and increase the light intensity as a means of post-correction. In detail, the adhesive layer Ah1 can be arranged around the light guide hole L0, the reflective layer hole RLH1 and the light-emitting unit LED on the upper surface of the light guide plate LGP (or between the light guide plate LGP and the light shielding sheet SS), and the adhesive layer Ah2 can be arranged around the light guide hole L0, the reflective layer hole RLH1 and the light-emitting unit LED on the lower surface of the light guide plate LGP (or between the light guide plate LGP and the light board LCB).

The glue layers Ah/Ah1/Ah2 are not suitable to be too close to the light-emitting unit LED. On the one hand, the light coupling effect of the glue layers Ah/Ah1/Ah2 will make the light of the light-emitting unit LED too concentrated and unable to diffuse. On the other hand, if the glue layers Ah/Ah1/Ah2 come into contact with the light-emitting unit LED for some reason during the process, their viscosity may cause the light-emitting unit LED to peel off. Therefore, the glue layers Ah/Ah1/Ah2 must be used under proper control, including setting the glue-free area CA or reducing the glue layer width. The glue-free area CA can be set between the glue layer Ah/Ah1/Ah2 and the light guide hole L0, or between the glue layer Ah/Ah1/Ah2 and the reflective layer hole RLH1. In the Z direction, the glue-free area CA can be set on the upper surface of the light guide plate LGP (or between the light guide plate LGP and the light shielding sheet SS), or the glue-free area CA can be set on the lower surface of the light guide plate LGP (or between the light guide plate LGP and the light board LCB). In practice, the glue layers Ah1/Ah2 can be set one by one, or both at the same time. The glue gap AP is another means of adjusting the glue layer Ah1/Ah2. If there is a need to increase the outline halo of the keycap KCC or the brightness of the outer characters (outer light-transmitting area KC1) in a certain direction, a gel gap AP can be opened in the gel layer Ah1/Ah2 to correspond to the required direction or light-transmitting area. The gel gap AP can allow more light to continue to be transmitted horizontally outward smoothly, thereby improving the light output brightness in that direction.

In general, the first light-distributing area, the second light-distributing area, and the third light-distributing area cover different blocks and different areas of the light-emitting unit LED in the 360-degree range from the Z direction. Due to the different configurations of the optical elements, the upward light output of the first light-distributing area/the second light-distributing area/the third light-distributing area can be relatively close. In addition, there are other elements that can be used as adjustment means. For example, the microstructure area MS on the surface of the light guide plate LGP can be used in combination with the core microstructure area CMS, the inner microstructure area IMS, and the outer microstructure area OMS of the first reflection layer RL1 of the light board LCB to increase the reflection and diffusion effects. In addition, covering the glue layer Ah1/Ah2 with the inner reflection area RL0 of the light shielding sheet SS can also reduce the light loss caused by the glue layer Ah1/Ah2 and recycle the light.

From the Z direction, in Figure 14A/14B, the light guide hole L0 is larger than the reflective layer hole RLH1 of the first reflective layer RL1, and the reflective layer hole RLH1 is larger than the light-emitting unit LED, that is, the wall of the reflective layer hole RLH1 surrounds the light-emitting unit LED and does not completely cover the two pads FP. In other words, the reflective layer hole RLH1 is located between the light-emitting unit LED and the light guide hole L0, and a portion of the first reflective layer RL1 (the innermost ring area) is located between the reflective layer hole RLH1 and the light guide hole L0. In this way, the two pads FP are at least partially exposed in the reflective layer hole RLH1. The exposure range of the pad FP directly affects the range of the LED light-emitting unit that can be smoothly connected even if it is offset during the assembly. Therefore, exposing more pads FP can ensure that the LED light-emitting unit can be smoothly connected to the pad FP. At the same time, exposing the pad FP means that there is no first reflective layer RL1 to provide reflection, but this does not mean that the reflective layer hole RLH1 cannot provide a reflective diffusion effect. First, since the pad FP is copper or copper alloy (or other alternative metals), the reflective layer hole RLH1 can provide a reflective diffusion effect in the light guide hole L0 through the branch line Br line segment exposed by the two pads FP (located between the LED light-emitting unit and the reflective layer hole RLH1). Secondly, the hollow areas of the exposed areas of the two pads FP (including the hollow areas Ha/Hb and the pad gap FG) usually expose the substrate of the light board LCB (located below the lines and pads FP). As long as the exposed upper surface of the substrate can reflect light, whether the upper surface of the substrate itself is reflective, or there is a metal solder/conductive layer there, or there is a colloid that ensures the fixation of the light-emitting unit LED, it can also provide a reflective diffusion effect.

Referring to Figure 14C, when the mass production yield rate has become stable, and the chipping accuracy, chipping temperature, conductive layer flow, and chipping offset of the light-emitting unit LED are well controlled, a smaller reflective layer hole RLH1 can be used. The smaller the reflective layer hole RLH1 is, even when the four sides of the light-emitting unit LED surround the hole wall of the reflective layer hole RLH1, the first reflective layer RL1 can almost fully cover the lamp board LCB within the range of the light guide hole L0, without exposing any part of the pad FP. At this time, the two completely covered pads FP, their branch lines Br and multiple hollow areas Ha/Hb can form multiple microstructures with complete shapes and larger areas, and constitute the core microstructure area CMS surrounding the light-emitting unit LED. The larger the area of the core microstructure region CMS, the more light can be diffused in the early stage, allowing more light to enter smoothly from the side wall of the light guide hole L0. The core microstructure region CMS may be partially located within the light guide hole L0, and partially located outside the hole wall of the light guide hole L0. Of course, the size and shape of the reflective layer hole RLH1 is similar to the light-emitting unit LED, or slightly larger than the light-emitting unit LED, which can also achieve a similar effect.

Based on the configuration of the above-mentioned embodiment, in Figures 14A to 14C, a portion of the multiple branch lines Br of the two pads FP together surround at least a portion of the light guide hole L0; a plurality of hollow areas Ha/Hb of the two pads FP together surround and/or overlap the reflective layer hole RLH1; an inner ring portion RL1i of a portion of the first reflective layer RL1 located between the reflective layer hole RLH1 and the light guide hole L0 overlaps at least a portion of the two pads FP, so that the local first reflective layer RL1 exposed in the light guide hole L0 can form a concave-convex reflective diffusion structure together with the local pads FP, such as a core microstructure area CMS. Finally, although each pad FP in each embodiment of the present invention is used as an example to connect the (sub) conductors STa/STb, in actual applications, each pad FP can also be selectively directly connected to the (main) conductors HT/LT mentioned in the aforementioned embodiments and Figures 2 to 11 as needed.

Referring to FIG. 14D , the light-emitting unit LED is packaged with three-color chips to provide three-color light (such as red, green, and blue). In order to achieve a good light-mixing effect for the three-color chips of the light-emitting unit LED, the aforementioned core microstructure area CMS surrounding the light-emitting unit LED is also formed in the inner ring portion RL1i of the first reflective layer RL1 (regardless of the presence of the aforementioned solder pad FP or the type of solder pad FP), so as to increase the light-mixing effect of the three-color chips of the light-emitting unit LED by improving the reflection and diffusion effects. In addition, the arrangement of the three-color chips can be arranged in a long-side to long-side sequence. The advantage is that the light-emitting unit LED is shorter, and the offset of the chip is less likely to interfere with the small-sized light guide hole L0, but the disadvantage is that the light-mixing effect is poor; because the long side of the chip with a larger light output is blocked by the long side of the adjacent chip, it is not easy for different colors of light to be transmitted crosswise. Another method is shown in Figure 14D. Each long side of the three-color crystal is parallel to the long side of the entire light-emitting unit LED. That is, each long side of the three-color crystal is arranged along the Y direction, or the three-color crystals are arranged in a row with their short sides facing each other. In this way, the long sides of the crystals with larger light output and larger light output range are facing the X direction in the figure and overlapping and interlacing with each other, so that a better light mixing effect can be achieved in the two larger fan-shaped ranges in the X direction; at the same time, in the Y direction, because the short sides of the crystals are adjacent, the light output of the short sides of the crystals is small and the light output range is small, the light blocked by the short sides of the crystals is also small, and the polarization problem caused is also small.

In summary, the embodiments provided in Figures 12A to 14C of the present invention solve the connection stability problem of the light-emitting unit and the problem of excessive light concentration in the vicinity of the light-emitting unit. In addition to using a solder pad with a hollow area to ensure that the light-emitting unit can still be connected smoothly when the component is offset, the solder pad and its hollow area are further used to form a light homogenization design of the first light homogenization area in combination with the first reflective layer; in addition, the light board is matched with the inner microstructure area of the second light homogenization area, the glue layer and the glue-free area of the third light homogenization area, and the present invention provides different light homogenization schemes for different blocks along the light path from the light-emitting unit to the outside, so that the character brightness and keycap halo of a single key, and even the entire keyboard range can achieve a high degree of uniformity.

In addition, the microstructure regions MS, LMS, inner microstructure region IMS, outer microstructure region OMS, core microstructure region CMS, etc. mentioned in the above embodiments are regions respectively constituted by a plurality of microstructures. In practice, as long as they are arranged on the same component surface, the above microstructure regions can be selectively integrated and arranged on one or more microstructure layers MSL. For example, the (first layer) microstructure layer MSL can include the inner microstructure region IMS, outer microstructure region OMS, and core microstructure region CMS (as shown in Figures 11, 14A-14D) that are simultaneously arranged on the first reflective layer RL1 of the light board LCB. The (second layer) microstructure layer MSL can include multiple microstructure regions LMS that can be arranged on the light guide plate LGP (as shown in Figure 3). If necessary, the (third layer) microstructure layer MSL can be disposed on the second reflective layer RL2 of the shading sheet SS. The significance of the (first and third layers) microstructure layer MSL located on the lamp board LCB and the shading sheet SS is that the proportion of total reflection of the internal light transmitted laterally by the light guide plate LGP is not as high as expected. As long as the angle between the light and the normal line of the light guide plate LGP is less than the critical angle, part of the light will be refracted to pass through the light guide plate LGP; in particular, the (second layer) microstructure layer MSL disposed on the light guide plate LGP corresponding to the key cap KCC, such as the microstructure area LMS in Figure 3, diffuses the light in multiple directions rather than 100% guiding the light vertically upward to pass through the light guide plate LGP. Therefore, the (first and third) microstructure layers MSL of the light board LCB and the shading sheet SS are needed to reflect and recycle the scattered light, so that it can return to the light guide plate LGP to continue to be transmitted horizontally. The microstructure diffusion effect of the (first and third) microstructure layer MSL helps to reach light in every direction of 360 degrees, thereby improving the luminous uniformity of the corner characters and outline halo of the keycap KCC.

Secondly, low-power light sources such as mini LED or micro LED are used in low-travel keys with short vertical light emission distance (1-2mm), while the target light emission area (covering the main character/sub-character/key cap edge halo) is large (about 10-12mm). If the number and power of light sources are not increased, pure optical means must be used to prevent light from escaping, increase the horizontal transmission distance of light, or increase the amount of light transmitted horizontally. However, in a small space, how to make 80% of the light emitted upward by the light source open the transmission angle so that most of the light enters the light guide plate for horizontal 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 (the critical angle of total reflection must be met), then the light will be wasted unnecessarily at the initial stage of the light source. Therefore, reducing the initial loss is another problem. Therefore, the backlight module BLM disclosed in the following embodiment of the present invention is provided with a protruding structure DP protruding toward the light-emitting unit LED to reduce the initial loss of light and open the light transmission angle so that more light enters the light guide plate LGP for lateral transmission.

Please continue to refer to Figures 14A, 14B, 14C and 14D. Referring to Figures 1 and 3, the luminous keyboard LKB provided in the following embodiments of the present invention includes a plurality of keys KS and a backlight module BLM. The key KS includes a key cap KCC, a support device SSR (see Figures 4, 6, 8, and 9), a circuit board MEM, and a base plate SUP; in addition, a reset member (not shown in the figure) is provided between the key cap KCC and the base plate SUP. The base plate SUP has an inner hole Sc and a peripheral hole SUPH at a position corresponding to the key cap KCC. When the base plate SUP is opaque (such as made of metal or opaque material), the inner hole Sc and the peripheral hole SUPH allow light from the backlight module BLM to pass through and illuminate the key KS.

Refer to Figures 14A, 14B and Figure 3. The backlight module BLM includes a shading sheet SS, a light guide plate LGP, a lamp plate LCB, and a protruding structure DP. The shading sheet SS is disposed between the key KS (bottom plate SUP) and the light guide plate LGP. The shading sheet SS can be provided with the aforementioned second reflective layer RL2 on the protective layer PL, for example, to reduce and/or prevent light from passing through a specific portion. At the light emitting position corresponding to the key cap KCC (such as the main/sub-character formed by the inner light-transmitting area KC0 and the outer light-transmitting area KC1), the light-shielding sheet SS does not have the second reflective layer RL2, so as to form the light emitting area OA of the backlight module BLM; the light emitting area OA is equivalent to the mask hole MLH of the mask layer ML of the light-shielding sheet SS, or the reflective layer hole RLH of the second reflective layer RL2, or the light emitting area OA is defined by the mask hole MLH and the reflective layer hole RLH. The halo of the four sides of the key cap contour controls the light emission through the four sides of the light emitting area OA; the longer the four sides of the light emitting area OA, or the closer to the edge of the key cap KCC, the greater the halo light emission. The second reflective layer RL2 may include an inner reflective area RL0 (block-shaped) and an outer reflective area RLF (frame-shaped). Among them, the light-emitting area OA surrounds the inner reflection area RL0, and the outer reflection area RLF surrounds the light-emitting area OA, so that the light-emitting area OA surrounds between the inner reflection area RL0 and the outer reflection area RLF. The outer reflection area RLF corresponds to the inner and outer areas of the periphery of the key cap KCC, preventing the user from seeing the bright spots under the bottom plate SUP (peripheral hole SUPH) (such as the microstructure introduced later) from the gap around the key cap KCC. The inner reflection area RL0 corresponds to covering the top of the light-emitting unit LED, which is to allow the strongest light to be reflected into the light guide plate LGP, avoid the problem of the main characters of the key cap KCC being too bright, help to improve the brightness of the edge or corner characters, and also help to improve the uniformity of the light emission of the key KS. If necessary, the light shielding sheet SS may include a mask layer ML to further shield the light penetrating the second reflective layer RL2. The mask layer ML is formed above the second reflective layer RL2 corresponding to the position of the light-emitting unit LED. The mask layer ML can be divided into an inner mask area ML0 (block shape) and an outer mask area MLF (frame shape).

The light guide plate LGP is located below the light shielding sheet SS, and the lamp board LCB is disposed below the light guide plate LGP and has a light-emitting unit LED. The light guide plate LGP has a light guide hole L0 at a position corresponding to the light-emitting unit LED, and the light-emitting unit LED is disposed in the light guide hole L0. The light-emitting unit LED includes one or more light-emitting bodies. The backlight module BLM may further include a microstructure layer MSL, and the microstructure layer MSL may be disposed parallel to the light guide plate LGP and the lamp board LCB. The microstructure layer MSL is disposed correspondingly in the area below the main character/sub-character of the keycap KCC, such as formed on the upper surface or lower surface of the light guide plate LGP (e.g., the microstructure area LMS in Figure 3), or formed on the upper surface of the reflective layer of the lamp board LCB, or independently formed between the light guide plate LGP and the lamp board LCB (e.g., the inner microstructure area IMS and the outer microstructure area OMS in Figure 3).

The protruding structure DP can be formed on the shading sheet SS and located above the light-emitting unit LED, and protrude toward the light-emitting unit LED, or in other words, protrude toward the light-emitting unit LED. The main purpose of providing the protruding structure DP is to diffuse the light and open or increase the light transmission angle (relative to the normal line of the top surface of the light-emitting unit LED), that is, to allow the light to have a larger lateral transmission component, so that more light can enter the light guide plate LGP at the initial stage of light emission, and be transmitted laterally in the light guide plate LGP through total reflection. In general, the protruding structure DP protruding toward the light-emitting unit LED/light board LCB of the present invention can be set on any component above the light-emitting unit LED, such as the shading sheet SS (Figures 3, 11, and 14B), the base plate SUP (not shown), or the circuit board MEM (protrusions 4, 6, 7, 8, and 9). The protruding structure DP can be formed integrally by the shading sheet SS, the base plate SUP or the circuit board MEM (for example, by stamping with a mold), or fixed as an independent component on the surface of the shading sheet SS, the base plate SUP or the circuit board MEM (for example, by printing or dotting paint, ink or glue to form a bump). The height of the protruding structure DP can be, for example, 18% to 95% of the thickness of the light guide plate LGP. The protruding structure DP on the shading sheet SS can be formed by the protruding portion of the protective layer PL, and the inner reflection area RL0 and the inner mask area ML0 are located on the upper surface and/or lower surface of the protruding portion of the protective layer PL. The independent protruding structure DP is located on the lower surface of the lowest layer among the protective layer PL, the inner reflection area RL0 and the inner mask area ML0.

The protruding structure DP protrudes toward the light-emitting unit LED or toward the lamp board LCB. This design is contrary to common sense. It will not only increase the thickness of the backlight module BLM at the light-emitting unit LED, but also interfere with the light-emitting unit LED and affect the light effect. When using low-power light sources such as mini LED or micro LED, the height of the light-emitting unit LED is greatly reduced compared to traditional LEDs, but the solder joint area is too small, which reduces the welding strength. In addition, the backlight module BLM and its light shielding sheet SS, light guide plate LGP and lamp board LCB have all undergone a process of thinning. The thickness at the light-emitting unit LED is too large, which may make the solder joint of the light-emitting unit LED easily touched by external force and break. The protruding structure DP protruding toward the light-emitting unit LED may cause the backlight module BLM to be too thick at the light-emitting unit LED, causing the top or bottom surface of the backlight module BLM to bulge. The convexity of the backlight module BLM means that the lamp board LCB protrudes downward at the light-emitting unit LED (similar to Figure 6), which causes the line of the lamp board LCB to bend locally near the light-emitting unit LED, making it possible for the light-emitting unit LED soldering to peel off. Alternatively, the light-shielding sheet SS may also convex upward at the light-emitting unit LED (similar to Figure 7). Regardless of whether the backlight module BLM is convex upward or downward at the light-emitting unit LED, the light-emitting unit LED may also interfere with the protruding structure DP, thereby damaging the phosphor on the surface of the light-emitting unit LED, ultimately causing color deviation problems (for example, white light is blue or multi-color mixed light has color deviation). The next problem is that if the protruding structure DP partially enters the light guide hole L0 of the light guide plate LGP, it will force the relative position of the light-emitting unit LED to move downward, affecting the optical coupling mechanism between the light-emitting unit LED and the wall of the light guide hole L0. Another problem is that if the light guide hole L0 of the light guide plate LGP cannot completely accommodate the protruding structure DP, the outer area of the protruding structure DP may cause unnecessary air gaps, resulting in light dissipation and loss, and failure to smoothly enter the light guide plate LGP. However, on the contrary, solving these problems also means that the present invention protrudes the protruding structure DP toward the light-emitting unit LED, which can be transformed into a favorable solution.

In FIG. 14B , the protruding structure DP is formed by the protection layer PL of the light shielding sheet SS protruding downward, or a transparent or non-transparent protrusion is formed at the same place, and the protruding direction is toward the light-emitting unit LED or toward the light board LCB. The inner reflection area RL0 and the inner mask area ML0 of the light shielding sheet SS can be overlapped and formed on the upper surface or lower surface of the protruding structure DP (the upper and lower surfaces of the protection layer PL at that place). In addition, the stacking order of the second reflection layer RL2 of the light shielding sheet SS, the mask layer ML and the protection layer PL is not limited, and the size ratio relationship between the second reflection layer RL2 and the mask layer ML, the ink color and the material type vary depending on the actual light output application of the backlight module BLM. For example, the second reflective layer RL2 (inner reflection area RL0) can be formed on the surface S2 of the protective layer PL below the protruding structure DP, and the mask layer NL (inner mask area ML0) can be formed between the second reflective layer RL2 (inner reflection area RL0) and the lower surface of the protective layer PL. Alternatively, the second reflective layer RL2 (inner reflection area RL0) can be formed on the lower surface of the protective layer PL above the protruding structure DP, and the mask layer ML (inner mask area ML0) can be formed on the upper surface of the protective layer PL above the protruding structure DP. The diffusion effect of the protruding structure DP can come from the second reflective layer RL2 (inner reflection area RL0) or the protruding structure DP itself; the smooth or rough curved surface of the protruding structure DP, or the protruding structure DP is made of reflective material, so that the protruding structure DP can provide the effect of diffusing light without the help of the second reflective layer RL2 (inner reflection area RL0). The protruding structure DP can have a single or multiple protrusions, or form a multi-point concave-convex area, which is set in close proximity within the light-emitting range of the light-emitting unit LED, such as an elliptical hemisphere with a horizontal angle of 360 degrees and a vertical angle of 120 degrees.

Regarding the interference problem between the protruding structure DP and the light-emitting unit LED, several solutions can be used to reduce the negative impact. For example, thinning the thickness of the shading sheet SS, improving the elasticity and surface smoothness of the shading sheet SS and its internal reflection area RL0 can reduce the negative impact of the protruding structure DP on the light-emitting unit LED during interference. In addition, by controlling the arc curvature of the mold, the arc curvature of the protruding structure DP can be increased, reducing the depth of the protruding structure DP entering the light guide hole L0 of the light guide plate LGP, thereby creating a safe distance between the protruding structure DP and the light-emitting unit LED. Another method is to apply glue (such as UV light curing glue) on the surface of the light-emitting unit LED, which can also allow an additional layer of protective glue to be added to the phosphor of the light-emitting unit LED as a safe distance between the protruding structure DP and the light-emitting unit LED. Alternatively, the lowest point of the protruding structure DP can be raised through design or mold processing, or even a part of the surrounding of the protruding structure DP can be slightly convex, so that a safe distance can be generated between the protruding structure DP and the light-emitting unit LED, and the overall thickness of the light-emitting unit LED position can be well controlled. Alternatively, the protruding structure DP is not directly facing the light-emitting unit LED, but at least partially surrounds the light-emitting unit LED to reduce the interference problem between the protruding structure DP and the light-emitting unit LED.

In addition, the present invention can further adopt a glue layer design. For example, as shown in Figures 14A and 14B, the backlight module BLM can further include at least one glue layer Ah. Figures 14A and 14B show that a glue layer Ah is attached between the light shielding sheet SS and the light guide plate LGP, and this glue layer Ah at least partially surrounds the protruding structure DP, the light guide hole L0 and the light-emitting unit LED. Figures 14A and 14B also show that another glue layer Ah is attached between the light guide plate LGP and the first reflective layer RL1, and this glue layer Ah also at least partially surrounds the protruding structure DP, the light guide hole L0 and the light-emitting unit LED. The aforementioned glue layer Ah is arranged parallel to the light shielding sheet SS, the light guide plate LGP, and the lamp panel LCB. A non-adhesive area CA may be preferably provided between the adhesive layer Ah and the light guide hole L0 of the light guide plate LGP. In a top view, the non-adhesive area CA at least partially surrounds the protruding structure DP to prevent the adhesive layer Ah from entering the light guide hole L0 of the light guide plate LGP and adhering to the light-emitting unit LED for some reason during the manufacturing process, resulting in excessive light emission or the light-emitting unit LED falling off. The non-adhesive area CA may be provided on the upper surface of the light guide plate LGP (or between the light guide plate LGP and the light shielding sheet SS), or the non-adhesive area CA may be provided on the lower surface of the light guide plate LGP (or between the light guide plate LGP and the light board LCB). The adhesive layer Ah has a good light coupling effect. Through the above-mentioned adhesive layer Ah design, the light of the light-emitting unit LED can smoothly reach the medium on the other side of the adhesive layer Ah when it is directly or indirectly incident on the adhesive layer Ah, so that the light can be reflected back to the light guide plate LGP between the second reflection layer RL2 and the first reflection layer RL1 after emitting from the light guide plate LGP, so as to avoid the light from being lost in the air gap between the light guide plate LGP and the light shielding sheet SS, or in another air gap between the light guide plate LGP and the first reflection layer RL1 of the lamp board LCB, so as to ensure that a sufficient proportion of light can continue to be transmitted horizontally in the light guide plate LGP to a farther position.

Through the above configuration, the protruding structure DP can diffuse the light and open or increase the light transmission angle (relative to the normal line of the top surface of the light-emitting unit LED), increase the lateral transmission component of the light, and allow more light to enter the light guide plate LGP for lateral transmission at the initial stage of light emission. Then, through the optical coupling effect of the adhesive layer Ah surrounding the protruding structure DP, the initial scattered light can be guided back to the light guide plate LGP. In addition, the light scattered from the upper and lower surfaces of the light guide plate LGP can be reflected and recycled to the light guide plate LGP through the first reflection layer RL1 and the second reflection layer RL2, ensuring that as much light as possible reaches the bottom of the side and corner of the key cap KCC. At this time, the light can be diffused upward through the microstructure layer MSL (as shown in Figures 3, 11, 14A, and 14B), allowing the light to pass through the light guide plate LGP upward. In this way, the light can continue to pass through the light-emitting area OA of the light-shielding sheet SS, the inner hole Sc and the peripheral hole SUPH of the bottom plate SUP, and the circuit board MEM in sequence and emit light from the key cap KCC, thereby generating the character luminescence and surrounding halo effect of the key cap KCC, and achieving a considerable degree of uniformity. Next, further integrating the protruding structure DP into the aforementioned embodiments of the present invention will obtain several optimized designs.

In Figure 14D, the light-emitting unit LED has multi-color dies arranged in a straight line along the short side, or each long side of the three-color dies is parallel to the long side of the entire light-emitting unit LED, that is, each long side of the three-color dies is arranged along the Y direction. Even if the arrangement in Figure 14D is not adopted, the design of the protruding structure DP protruding toward the light-emitting unit LED and the light board LCB can still help diffuse different colors of light, help the three-color dies of the light-emitting unit LED to fully mix light at a very short distance, and reduce color deviation problems.

Please refer to Figures 3, 14A, and 14B. The first preferred design of the backlight module BLM of the present invention is to combine the protruding structure DP with the pad FP to produce an optical effect of uniform lighting. This backlight module BLM at least includes a shading sheet SS, a lamp board LCB, and a protruding structure DP. The lamp board LCB has a light-emitting unit LED and a pair of pads FP respectively connected to the light-emitting unit LED. Each of the pair of pads has one or more hollow areas Ha/Hb, and these hollow areas Ha/Hb at least partially overlap the light-emitting unit LED. The protruding structure DP is formed on the shading sheet SS and protrudes toward the lamp board LCB. The protruding structure DP at least partially overlaps the aforementioned pair of pads FP to diffuse the local light of the light-emitting unit LED between the protruding structure DP and the pair of pads FP. The significance of overlapping pads FP is that the protruding structure DP is directly above the light-emitting unit LED. For the light-emitting unit LEDs such as mini LED or Micro LED, which currently emit nearly 80% of light upward, it can reflect and diffuse the early light emitted by the light-emitting unit LED to the greatest extent. Secondly, pad FP is partially exposed outside the light-emitting unit LED, which allows the metal surface of the exposed part of pad FP to reflect the light diffused by the protruding structure DP and enter the light guide plate LGP for horizontal transmission; or, pad FP can be partially covered by the inner ring part RL1i of the first reflective layer RL1 of the lamp board LCB, and when the protruding structure DP overlaps pad FP, it also overlaps the inner ring part RL1i, so that the inner ring part RL1i can also reflect the light diffused by the protruding structure DP. Therefore, the local light of the light-emitting unit LED can be diffused between the protruding structure DP and a pair of pads FP, and enter the light guide plate LGP for horizontal transmission.

Please refer to Figures 3, 11, 14A, and 14B. The second preferred design of the backlight module BLM of the present invention is to combine the protruding structure DP with the microstructure area MS of the lamp panel LCB to produce an optical effect of uniform lighting. The backlight module BLM at least includes a light shielding sheet SS, a light guide plate LGP, a lamp panel LCB, and a protruding structure DP. The lamp board LCB includes two non-intersecting conductors (for example, main conductors HT and LT, or sub-conductors STa and STb), a plurality of microstructure regions (for example, inner microstructure region IMS, outer microstructure region OMS, or core microstructure region CMS), and at least one light-emitting unit LED, the light-emitting unit LED is connected between the two non-intersecting conductors (HT and LT, or STa and STb), and the plurality of microstructure regions (for example, inner microstructure region IMS, outer microstructure region OMS, or core microstructure region CMS) and the two non-intersecting conductors do not overlap (HT and LT, or STa and STb). The light guide plate LGP is disposed on the lamp board LCB; the light shielding sheet SS is disposed on the light guide plate LGP. The protruding structure DP is formed on the shading sheet SS and protrudes toward the lamp board LCB. The protruding structure DP is located between a plurality of microstructure regions (such as the inner microstructure region IMS or the outer microstructure region OMS or the core microstructure region CMS), thereby diffusing the local light of the light-emitting unit LED to enter the light guide plate LGP for horizontal transmission. The significance of the protruding structure DP and the microstructure area MS located in the light board LCB is to add and multiply the effect of the protruding structure DP diffusing the light into the light guide plate LGP for lateral transmission at the initial stage of the light path, and the effect of the core microstructure area CMS, the inner microstructure area IMS or the outer microstructure area OMS, etc., reflecting and recycling the light back to the light guide plate LGP for continued transmission in the subsequent light path, so as to achieve the result of the single key and multi-key luminous brightness equalization of the above-mentioned keys KS in each embodiment of the present invention.

Please refer to Figures 3, 11, 14A, and 14B. The third preferred design of the backlight module BLM of the present invention is to combine the protruding structure DP with the microstructure area MS of the lamp board LCB to produce an optical effect of uniform lighting. The backlight module BLM includes a first light-homogenizing area Z1 surrounding the light-emitting unit LED to homogenize the light of the light-emitting unit LED. The first light-homogenizing area Z1 includes a protruding structure DP, a pair of welding pads FP, and a first reflective layer RL1. The protruding structure DP is formed on the shading sheet SS and protrudes toward the lamp board LCB. The protruding structure DP can diffuse the light of the light-emitting unit LED. The welding pad FP is located on the lamp board LCB for connecting the light-emitting unit LED. The first reflective layer RL1 is disposed on the lamp board LCB and has an inner ring portion RL1i that at least partially covers the butt pad FP, and the inner ring portion RL1i of the first reflective layer RL1 reflects light from the light-emitting unit LED and/or the protruding structure DP; this means that the first reflective layer RL1 also surrounds the light-emitting unit LED, in particular, the annular area of the first reflective layer RL1 within the light guide hole L0 of the light guide plate LGP; in addition, the first reflective layer RL1 also surrounds the protruding structure DP and the butt pad FP at the same time in a top view. Since the portion of the butt pad FP covered by the inner ring portion RL1i of the first reflective layer RL1 can form a core microstructure area CMS with better reflection and diffusion effects, the light directly from the light-emitting unit LED (such as side light emission) or the light indirectly diffused by the protruding structure DP can be further reflected and diffused by the inner ring portion RL1i of the first reflective layer RL1 so as to enter the light guide plate LGP for lateral transmission. In addition, the backlight module BLM may also include a second light-distributing area Z2 surrounding the first light-distributing area Z1. The second light-distributing area Z2 includes a pair of microstructure areas IMS spaced apart from each other and located on the first reflective layer RL1. The pair of microstructure areas IMS are located on opposite sides of the protruding structure DP (and the butt pad FP) (in a top view).

Please refer to Figure 11. A better design of the luminous keyboard LKB of the present invention is to use a multi-protrusion structure DP to produce an optical effect of uniform lighting between multiple keys KS. The key caps KCC of two adjacent keys KS2 and KS3 are arranged in the same horizontal row, and the backlight module BLM is located below the two adjacent key caps KCC. The shading sheet SS has at least two light emitting areas OA corresponding to the two adjacent key caps KCC of the keys KS2 and KS3 respectively. The light board LCB has at least two light emitting units corresponding to the at least two light emitting areas OA of the shading sheet SS corresponding to the keys KS2 and KS3 respectively. At least two protruding structures DP are formed in at least two light emitting areas OA of the light shielding sheet SS, and protrude toward the lamp board LCB, respectively. The at least two protruding structures DP diffuse the local light of the at least two light emitting units LED, respectively enter the light guide plate LGP for horizontal transmission, and irradiate the at least two adjacent key caps KCC of the keys KS2 and KS3 through the at least two light emitting areas OA of the light shielding sheet SS. In a top view, the lamp board LCB has a microstructure area MS (composed of two adjacent inner microstructure areas IMS) located between the at least two protruding structures DP, and the microstructure area MS spans the gap Gx in the X direction between the at least two adjacent key caps KCC of the keys KS2 and KS3. The significance of this design is that the adjacent keys KS2 and KS3 use the exclusive protruding structure DP to diffuse light respectively, so that the two adjacent keycaps KCC can achieve uniform lighting within the single key range. When the same specification/number of light-emitting unit LEDs and keycap KCC sizes are used, the two adjacent keycaps KCC can achieve consistent lighting uniformity.

Please refer to FIG. 11. Another preferred design of the luminous keyboard LKB of the present invention is to use multiple protruding structures DP and microstructure regions MS to produce uniform light emission between multiple keys KS and reduce light leakage. Among the three adjacent keys, the key caps KCC of two keys KS2 and KS3 are arranged in the same horizontal row, the key cap KCC of key KS1 is arranged in another adjacent horizontal row in the Y direction, and the backlight module BLM is located below the three adjacent key caps KCC. The light shielding sheet SS has at least three light emitting areas OA corresponding to the three adjacent key caps KCC of keys KS1, KS2 and KS3. The lamp board LCB has at least three light-emitting units LED corresponding to three phase neighboring key caps KCC of keys KS1, KS2 and KS3 respectively. At least three protruding structures DP are formed on the shading sheet SS and protrude toward the lamp board LCB respectively. The at least three protruding structures DP diffuse the local light of the at least three light-emitting units LED respectively, so as to enter the light guide plate LGP for horizontal transmission respectively, and irradiate the at least three phase neighboring key caps KCC of keys KS1, KS2 and KS3 through the at least three light-emitting areas OA of the shading sheet SS. Among them, the backlight module BLM has a plate hole BH and at least one microstructure area MS (for example, three outer microstructure areas OMS) surrounding the plate hole BH, and the plate hole BH penetrates the shading sheet SS, the light guide plate LGP and the lamp board LCB. This at least one microstructure area MS is located between the plate hole BH and the at least three protruding structures DP in a top view, which means that the at least three protruding structures DP greatly increase the light component transmitted laterally, and also highlight the problem of light leakage from the plate hole BH. Since the three external microstructure areas OMS are not only distributed in the vertical projection range of the at least three adjacent key caps KCC of the keys KS1, KS2 and KS3, but also distributed all the way to the gaps Gx and Gy in the X direction and Y direction, and then surround the plate hole BH. It is equivalent to that the three external microstructure areas OMS constitute a merged microstructure area MS that overlaps the gaps Gx and Gy between the three key caps KCC, so that this merged microstructure area MS also surrounds the plate hole BH located in the gaps Gx and/or gaps Gy. Therefore, when the light path goes beyond the light exit area OA, the excess light can be reflected, diffused, and consumed in advance through at least one of the aforementioned microstructure areas MS (three outer microstructure areas OMS) to reduce the light component reaching the plate hole BH and reduce light leakage from the plate hole BH. The aforementioned microstructure area MS is not limited to the three outer microstructure areas OMS located on the first reflection layer RL1 of the light board LCB. As mentioned above, the microstructure area LMS can be set on the light guide plate LGP in Figure 3, and even the microstructure area MS can be set on the second reflection layer RL2 of the light shielding sheet SS. The three layers of microstructure areas MS can be used independently or in combination to reduce the light component reaching the plate hole BH in the area beyond the light exit area OA. Another thing that can be used is the light coupling effect of the glue layer Ah. The glue layer Ah surrounds the plate hole BH, and the aforementioned merged microstructure area MS is also located between the glue layer Ah and the three protruding structures DP. The glue layer Ah can consume light in advance. If necessary, a non-glue area CA can be set around the plate hole BH, and the glue layer Ah surrounds the non-glue area CA to prevent the glue layer Ah from being too close to the plate hole BH and leaking light. In this way, the aforementioned at least one microstructure area MS is located between the glue layer Ah and at least three protruding structures DP, and the three provide diffused light, light-guiding light, and diffused loss at different stages of the light path, and finally reduce the light leakage of the plate hole BH.

In summary, the present invention adopts the arrangement of overlapping the protruding structure and the light source, 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 or the light panel, so as to open the light transmission angle, increase the lateral transmission component, and increase the amount of light entering the light guide plate LGP. In this way, in addition to preventing the middle characters from being too bright, the brightness of the side or corner characters is also improved, or the light mixing effect of the multi-color crystals of the light-emitting unit is improved, thereby greatly improving the light uniformity of the backlight keys and the visual aesthetic effect when in use. Before exceeding the light-emitting area of the light-shielding sheet and reaching the plate hole at the end of the light path, the protruding structure can also be used in combination with the microstructure area and the glue layer to achieve the effect of reducing light leakage.

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.

LCB: Light Board

STa, STb: conductors

LED: light emitting unit

RL1: First reflection layer

RL0: internal reflection area

ML0: Inner mask area

IMS: Internal Microstructure Zone

CMS: nuclear microstructure region

L0: light guide hole

Ah: glue layer

AP:Colloid gap

Br: branch line

CA: glue-free area

DP: Prominent structure

FG: Pad gap

Ha,Hb: hollow area

RL1i: Inner ring part

RLH1: Reflection layer hole

Claims (17)

A backlight module is used to illuminate at least one keycap. The backlight module comprises: a light board, comprising two non-intersecting wires, a plurality of microstructure areas and at least one light-emitting unit, the light-emitting unit is connected between the two non-intersecting wires, the plurality of microstructure areas do not overlap with the two non-intersecting wires, the two non-intersecting wires comprise two main wires spaced apart from each other, the plurality of microstructure areas comprise a pair of outer microstructure areas spaced apart from each other and respectively located outside the two main wires; a light guide plate, disposed on the light board; a light shielding sheet, disposed on the light guide plate; and a protruding structure, formed on the light shielding sheet and protruding toward the light board, the protruding structure is located between the plurality of microstructure areas, and the protruding structure diffuses the light of the light-emitting unit to enter the light guide plate for lateral transmission. The backlight module as described in claim 1, wherein the light panel further includes a first reflective layer surrounding the light-emitting unit and the protruding structure. The backlight module as described in claim 2, wherein the light guide plate has a light guide hole for accommodating the light-emitting unit, and the first reflective layer is at least partially located in the light guide hole. The backlight module as described in claim 2, wherein the light guide plate has a light guide hole for accommodating the light-emitting unit, the first reflective layer has a reflective layer hole, and the first reflective layer is at least partially located between the reflective layer hole and the light guide hole. A backlight module as described in claim 2, wherein the light shielding film includes an internal reflection area overlapping the protruding structure and the first reflection layer. The backlight module as described in claim 1 further comprises a glue layer at least partially surrounding the protruding structure. The backlight module as described in claim 1, wherein the light-emitting unit comprises at least three chips providing at least three colors of light, and the at least three chips are arranged in sequence with their short sides facing each other. A backlight module as described in claim 1, wherein the protruding structure is located between the two non-intersecting conductive lines. The backlight module as described in claim 1, wherein the plurality of microstructure regions include a pair of inner microstructure regions spaced apart from each other, and the pair of inner microstructure regions are located on opposite sides of the protruding structure. A backlight module as described in claim 1, wherein the plurality of microstructure regions include a pair of inner microstructure regions spaced apart from each other and located between the two main conductors. The backlight module as described in claim 1, wherein the light panel has two sub-conductors respectively electrically connected to the pair of main conductors, and the plurality of microstructure regions include a pair of inner microstructure regions spaced apart from each other and located on opposite sides of the two sub-conductors. A light-emitting keyboard comprises: at least two adjacent key caps; and a backlight module located below the at least two adjacent key caps, the backlight module comprising: a light shielding sheet having at least two light-emitting areas corresponding to the at least two adjacent key caps; a light board having at least two light-emitting units respectively corresponding to the at least two light-emitting areas, the light board having a pair of non-intersecting wires across the at least two adjacent key caps; and at least two protruding structures respectively formed in the at least two light-emitting areas of the light shielding sheet and protruding toward the light board respectively, the at least two protruding structures respectively diffuse the local light of the at least two light-emitting units, and the at least two protruding structures are located between the pair of non-intersecting wires. The luminous keyboard as described in claim 12, wherein the light panel has a microstructure area located between the at least two protruding structures, and the microstructure area spans the gap between the at least two adjacent key caps. A light-emitting keyboard comprises: at least three adjacent key caps; and a backlight module located below the at least three adjacent key caps, the backlight module comprising: a shading sheet; a light board having at least three light-emitting units corresponding to the at least three adjacent key caps; and at least three protruding structures, respectively formed on the shading sheet and protruding toward the light board, respectively, the at least three protruding structures respectively diffuse the local light of the at least three light-emitting units; wherein the backlight module has a plate hole and at least one microstructure area surrounding the plate hole, the at least one microstructure area is located between the plate hole and the at least three protruding structures in a top view. A luminous keyboard as described in claim 14, wherein the plate hole and the at least one microstructure region at least partially overlap a gap between the at least three adjacent key caps. The luminous keyboard as described in claim 14, wherein the backlight module further comprises a glue layer surrounding the plate hole, and the at least one microstructure is located between the glue layer and the at least three protruding structures. The luminous keyboard as described in claim 16, wherein the backlight module further includes a glue-free area between the plate hole and the glue layer.