TWI501278B - Backlight apparatus and illuminated keyboard including such backlight apparatus - Google Patents

Description

Backlight device and illuminated keyboard including the same

The present invention relates to a backlight apparatus and an illuminated keyboard including the same, and particularly to a backlight device having a reduced number of light sources, a small area circuit board, and avoiding dark areas, and including The keyboard portion of the backlight device.

The illuminated keyboard has been a common input peripheral device on the market. In current backlighting devices for illuminated keyboards, some prior art techniques have arranged a large number of light sources (typically light emitting diodes) along one of the long sides of the light guide plate. However, this prior art not only employs a large number of light sources, but also a large area required for a flexible circuit board on which the light source is fixed.

Other prior art techniques have arranged the light sources along one of the short sides of the light guide. However, dark areas may occur in the backlight away from the light source. Even the prior art would arrange the light source on the other short side. However, the number of light sources employed in this prior art may not be reduced, and the area required for the flexible circuit board on which the light source is fixed is limited to a limited extent.

Please refer to FIG. 1. FIG. 1 is a top view of a backlight device 1 of the prior art. The backlight device 1 includes a light guide plate 10, a flexible circuit board 12, and a plurality of light emitting diodes 14. The light guide plate 10 has a long side 101, a front surface 102, and a back surface opposite to the front surface 102 (not shown in FIG. 1). The light guide plate 10 also has a plurality of through openings 104. In particular, the plurality of through openings 104 are generally aligned along the centerline of the vertical long sides 101. Each opening 104 has a self The entrance surface 106. Each of the light emitting diodes 14 corresponds to an opening 104. A plurality of light emitting diodes 14 are fixed to the flexible circuit board 12. The flexible circuit board 12 is disposed on the back surface of the light guide plate 10 such that each of the light emitting diodes 14 is placed in its corresponding opening 104. The light emitted by each of the light-emitting diodes 14 is incident on the light guide plate 10 from the light-incident surface 106 of the corresponding opening 104, and is conducted inside the light guide plate 10, thereby being emitted from the front surface 102 of the light guide plate 10. The arrangement of the plurality of light-emitting diodes 14 causes the light rays to be staggered left and right to avoid dark areas. However, the area required for the flexible circuit board 12 employed in this prior art also has room for improvement.

Therefore, one technical problem to be solved by the present invention is to provide a backlight device having a small-area circuit board and avoiding occurrence of dark areas, and an illuminated keyboard including the same.

A backlight device according to a preferred embodiment of the present invention includes a light guide plate, a light emitting device, and a plurality of light redirecting structures. The light guide plate has a front surface, a back surface, side edges, and a plurality of openings. The openings are close to the sides of the light guide plate. Each opening has its own light entrance surface. A plurality of light exit regions are defined on the front surface of the light guide plate. The illuminating device comprises a circuit board and a plurality of light sources. Each light source is fixed to the circuit board and corresponds to an opening. Each light source is placed within its corresponding opening. The light emitted by each of the light sources is incident on the light guide plate from the light incident surface of its corresponding opening, and is conducted inside the light guide plate. A plurality of light-steering structures are disposed on the back surface of the light guide plate for guiding the light that is directed to the plurality of light-steering structures to the front surface of the light guide plate, and then emitted from the light-emitting areas of the front surface of the light guide plate.

An illuminated keyboard of a preferred embodiment of the present invention includes a substrate, a backlight, and a keyboard portion. The backlight device is disposed on the substrate. The keyboard portion is disposed on the backlight device. Light emitted from the front surface of the light guide plate is directed toward the keyboard portion.

Unlike the prior art, the backlight device of the present invention has a reduced number The light source is with a smaller area board.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

1‧‧‧Backlight

10‧‧‧Light guide plate

101‧‧‧Long side

102‧‧‧ positive

104‧‧‧ openings

106‧‧‧Into the glossy surface

12‧‧‧Soft circuit board

14‧‧‧Lighting diode

2‧‧‧Lighting keyboard

20‧‧‧ Keyboard Department

202‧‧‧ button

202a‧‧‧ long key

202b, 202c‧‧‧ function keys

202d‧‧‧Digital keypad

22‧‧‧Substrate

3‧‧‧Backlight

30‧‧‧Light mask

302‧‧‧Transmission Department

32‧‧‧Light guide plate

320‧‧‧ positive

321‧‧‧ side (long side)

322‧‧‧Back

324‧‧‧ openings

325‧‧‧Into the glossy surface

326‧‧‧Lighting area

326a, 326b, 326c‧‧‧ areas

327‧‧‧ trench

328‧‧ Dark area

329‧‧‧ Short side

34‧‧‧Lighting device

342‧‧‧ circuit board

344‧‧‧Light source

344a, 344b, 344c‧‧‧ external light source

344d‧‧‧ internal light source

36‧‧‧Light steering structure

38‧‧‧reflector

382‧‧‧through hole

C‧‧‧ center point

1 is a top plan view of a prior art backlight device.

2 is a development view of components of an illuminated keyboard in accordance with a preferred embodiment of the present invention.

Figure 3 is a top plan view of a light emitting device of the present invention.

4 is a partial cross-sectional view of a backlight device in accordance with a preferred embodiment of the present invention.

Figure 5 is a partial cross-sectional view showing a variation of one of the backlight devices of the present invention.

Figure 6 is a partial cross-sectional view showing another variation of the backlight device of the present invention.

Figure 7 is a partial cross-sectional view showing another variation of the backlight device of the present invention.

Figure 8 is a partial top plan view of a light guide plate of the present invention.

Figure 9 is a top plan view of a light guide plate of the present invention.

Figure 10 is a developmental view of a variation of one of the illuminated keyboards of the present invention.

Figure 11 is a top plan view of a variation of one of the illumination devices of the present invention.

Figure 12 is a top plan view showing another variation of the light-emitting device of the present invention.

Please refer to Figure 2. Figure 2 is a schematic exploded view of a lighted keyboard 2 in accordance with a preferred embodiment of the present invention.

As shown in FIG. 2, the illuminated keyboard 2 of the present invention includes a substrate 22, a backlight device 3 of the present invention, and a keyboard portion 20. The backlight device 3 is provided on the substrate 22, and the keyboard portion 20 is provided on the backlight device 3. The keyboard unit 20 includes a plurality of Button 202. Light emitted from the front surface 320 of the light guide plate 32 of the backlight device 3 is directed to a plurality of buttons 202.

Please refer to Figure 2, Figure 3 and Figure 4. Figure 3 is schematically drawn in a top view A light emitting device 34 of a specific embodiment of the present invention is shown. 4 is a partial cross-sectional view of the backlight device 3 of FIG. 2.

As shown in FIG. 2 and FIG. 4, the backlight device 3 of the present invention includes light guide Plate 32, illumination device 34, and a plurality of light redirecting structures 36. The light guide plate 32 has a front surface 320, a back surface 322, side edges 321 and a plurality of openings 324. The openings 324 are formed on the back surface 322 of the light guide plate 32 and are adjacent to the side edges 321 of the light guide plate 32. In FIG. 2, the openings 324 are close to the long sides 321 of the light guide plate 32, but the invention is not limited thereto. Each opening 324 has its own light incident surface 325. A plurality of light exit regions 326 are defined on the front surface 320 of the light guide plate 32. It must be stated here that the plurality of light exit zones 326 are not physical structures but are predetermined areas.

Further, as shown in FIGS. 2 and 4, the backlight device 3 of the present invention A light shielding film 30 is also included. The light shielding film 30 has a plurality of light transmitting portions 302. The plurality of transparent portions 302 may be hollowed out, but not limited thereto. Each of the light transmitting portions 302 corresponds to one light exiting region 326. The light shielding film 30 is disposed on the front surface 320 of the light guide plate 32. A plurality of light redirecting structures 36 are located below the plurality of light exiting regions 326.

In a specific embodiment, the light guide plate 32 can be made of acrylic, Made of silicone, thermoplastic polyurethane (TPU) or other commercial light-guided polymer materials. The layer thickness of the light guide plate 32 can be determined as needed, and is not particularly limited. For example, in one example, the thickness of the light guide plate 32 ranges from about 0.125 mm to 0.25 mm.

The light emitting device 34 includes a circuit board 342 and a plurality of light sources 344. In particular, the light sources 344 are arranged in an arc or a U-shape on the circuit board 342, and the light emitted by the light sources 344 is radiated into the light guide plate. 32 inside. As shown in FIGS. 2 and 3, the light sources 344 are arranged in an arc on the circuit board 342. In the partial cross-sectional view of FIG. 4, only the light source 344 arranged at both ends of the light source 344, that is, the light source 344a and the light source 344b in FIG. 4 are shown.

In a specific embodiment, the circuit board 342 can be a flexible circuit. Board, but the invention is not limited thereto.

In one embodiment, each of the light sources 342 can be illuminated A diode or an organic light emitting diode, but the invention is not limited thereto.

In a specific embodiment, the keyboard portion 20 includes a multiple key 202a, the openings 324 are located below the multiple key 202a, that is, the openings 324 are formed in the region 326a of the light guide plate 32 corresponding to the multiple key 202a. In the example shown in FIG. 2 and FIG. 4, the multiple key 202a is a blank key, but the invention is not limited thereto. Also in the example shown in Figs. 2 and 4, the blank key 20a has an intermediate portion which is located below the intermediate portion of the blank key 20a. In the example shown in FIG. 4, only the portion corresponding to the blank key 20a and the backlight device 3 of the adjacent button 202 is shown, and the light transmitting portion 302 corresponding to the light shielding film 30 of the adjacent button 202 is oppositely shown. The light exiting area 326 of the light panel 32. The blank key 20a shown in FIG. 2 and FIG. 4 is not transparent, but the invention is not limited thereto.

Each of the light sources 344 is fixed to the circuit board 342, and Corresponding to one opening 324. The illumination device 34 is disposed on the back surface 322 of the light guide plate 32 such that each of the light sources 344 is disposed within its corresponding opening 324. Light emitted by each of the light sources 344 is incident on the light guide plate 32 from the light incident surface 325 of its corresponding opening 324 and is conducted within the light guide plate 32.

A plurality of light redirecting structures 36 are disposed on the back of the light guide plate 32 322 is configured to direct light directed to the plurality of light redirecting structures 36 toward the front side 320 of the light guide plate 32 and further from the light exit regions 326 of the front side 320 of the light guide plate 32.

In a specific embodiment, the plurality of light redirecting structures 36 can A dot-colored (for example, white) ink is printed on the back surface 322 of the light guide plate 32, and may be formed by micro-lens or integrally formed with the light guide plate 32 by a plating method. However, the formation of the plurality of light redirecting structures 36 is not limited to the above process.

Further, the backlight device 3 of the present invention further includes a reflection sheet 38. The reflective sheet 38 is attached to the back surface 322 of the light guide plate 32 to assist in reflecting light. In FIG. 4, the reflection sheet 38 has a through hole 382, and the light emitting device 34 is disposed in the through hole 382.

Please refer to Figure 5. FIG. 5 is a partial cross-sectional view showing a variation of one of the backlight devices 3 of FIG. In this variation, the openings 324 extend through the light guide plate 32. The opening 324 penetrating the light guide plate 32 is suitable for the thin light guide plate 32. The components in FIG. 5 having the same reference numerals as those in FIG. 4 have the same or similar structures and functions, and will not be further described herein.

Please refer to Figure 6. Figure 6 is a partial cross-sectional view showing another variation of the backlight unit 3 of Figure 2. In this variation, the openings 324 are formed on the front surface 320 of the light guide plate 32 instead of the back surface 322 of the light guide plate 32. The light emitting device 34 is disposed on the front surface 320 of the light guide plate 32 instead of being disposed on the back surface 322 of the light guide plate 32. The components in FIG. 6 having the same reference numerals as in FIG. 4 have the same or similar structures and functions, and will not be described herein. In particular, the reflection sheet 38 has no through hole 382.

Please refer to Figure 7. FIG. 7 is a partial cross-sectional view showing another variation of the backlight device 3 of FIG. 2. In this variation, the openings 324 extend through the light guide plate 32. The light emitting device 34 is disposed on the front surface 320 of the light guide plate 32 instead of being disposed on the back surface 322 of the light guide plate 32. The components in FIG. 7 having the same reference numerals as those in FIG. 4 have the same or similar structures and functions, and will not be further described herein. In particular, the reflection sheet 38 has no through hole 382.

Please refer to Figure 8. Figure 8 is a partial top view of the light guide plate 32 of the present invention. Figure. As shown in FIG. 8, the light guide plate 32 of the present invention is likely to have a dark region 328. Generally, the dark region 328 may occur at the corner of the same side 321 of the light guide plate 32 and the light-emitting device 34, as shown in FIG.

In order to eliminate the dark area 328, the light guide plate 32 also has a groove 327, such as Figure 8 shows. In FIG. 8, dark region 328 is adjacent to side edge 321 and away from such openings 324. In the example shown in FIG. 8, the groove 327 is formed on the front surface 320 of the light guide plate 32. In other examples, the trench 327 may also be formed on the back surface 322 of the light guide plate 32. Light rays that are conducted within the light guide plate 32 and that are directed toward the grooves 327 are directed to the dark regions 328, thereby eliminating the dark regions 328.

In addition, to eliminate the dark area 328, the light source The light sources (344a, 344b) arranged at both ends of 344 have higher luminous intensities than the other light sources 344, thereby eliminating dark areas 328.

Please refer to Figure 9. Figure 9 is a top plan view of the light guide plate 32 of the present invention. As shown in FIG. 9, the light guide plate 32 may be rectangular and has a long side 321 and a short side 329. The openings 324 on the light guide plate 32 are also arranged in an arc or a U-shape relative to the light sources 344 arranged in an arc or a U-shape on the circuit board 342. In the example shown in FIG. 9, the center points of the openings 324 arranged in an arc or a U-shape are substantially on the center line of the long side 321 and near the long side 321 . This design allows the light distribution of the entire light guide plate 32 to be uniform.

Please refer to FIG. 10, FIG. 11 and FIG. Figure 10 shows another component exhibition The open drawing schematically illustrates a variation of the illuminated keyboard 2 of the present invention. 11 and 12 are schematic top views schematically showing variations of the light-emitting device 34 of the present invention.

The components of the illuminated keyboard 2 shown in FIG. 10 and the illuminated keys shown in FIG. The components of the disc 2 are substantially the same. The difference is that the length of the double key 202a of the keyboard portion 20 is short. In order to illuminate the numeric keypad 202d of the keyboard portion 20, the illumination device 34 must be disposed below the at least one function key between the multiple key 202a and the numeric keypad 202d and immediately adjacent to the multiple key 202a. In the example shown in FIG. 10, the light-emitting device 34 is disposed adjacent to the function key 202b next to the multiple key 202a, and functions. Below the key 202c. That is, the openings 324 are formed in the partial region 326a of the light guide plate 32 corresponding to the multiple key 202a and in the region 326b and the region 326c corresponding to the function key 202b and the function key 202c.

However, the arrangement of the light sources 344 is as shown in FIG. 2 and FIG. With the arrangement of the light sources 344, the light emitted by the light sources 344 cannot illuminate the function keys 202b and the function keys 202c next to the multiple keys 202a. Therefore, as shown in FIGS. 10 and 11, the light source 344 includes a plurality of external light sources (344a, 344b, and 344c) and an internal light source 344d. In particular, the external light sources (344a, 344b, 344c) are arranged in an arc or a U shape. The outer light source (344a, 344b, 344c) arranged in an arc or a U-shape has a first end position and a second end position, the outer light source 344a is located at the first end position, and the outer light source 344b is positioned at the second end position. The internal light source 344d is disposed in the external light sources (344a, 344b, 344c) as shown in FIGS. 10 and 11. The inner light source 344d is adjacent to the first end position and emits light toward the second end position. Thereby, the light-emitting device 34 shown in FIGS. 10 and 11 can illuminate the function key 202b and the function key 202c next to the double key 202a.

In another specific embodiment, as shown in FIG. 12, at the second end No external light source is provided at the position, that is, the external light source 344b in Fig. 11 is not provided. The light-emitting device 34 shown in Fig. 12 can illuminate the numeric keypad 202d of the keyboard portion 20, and can also illuminate the function key 202b and the function key 202c next to the double key 202a. The number of light sources of the light-emitting device 34 shown in Fig. 12 is smaller than the number of light sources of the light-emitting device 34 shown in Fig. 11.

With the details of the above preferred embodiments, it is hoped that The features and spirit of the present invention are clearly described, and the scope of the present invention is not limited by the preferred embodiments disclosed herein. On the contrary, the intention is to cover various modifications and equivalents that are within the scope of the invention as claimed. Therefore, the scope of the patent application of the present invention should be construed broadly in the light of the above description, so that it covers all possible changes and arrangements.

3‧‧‧Backlight

30‧‧‧Light mask

302‧‧‧Transmission Department

32‧‧‧Light guide plate

320‧‧‧ positive

322‧‧‧Back

324‧‧‧ openings

325‧‧‧Into the glossy surface

326‧‧‧Lighting area

326a‧‧‧Area

34‧‧‧Lighting device

342‧‧‧ circuit board

344a, 344b‧‧‧ light source

36‧‧‧Light steering structure

38‧‧‧reflector

382‧‧‧through hole

Claims (13)

A backlight device for an illuminated keyboard, comprising: a light guide plate having a front surface, a back surface, a side edge and a plurality of openings, the openings being adjacent to the side edges, each opening having a light incident surface, the front surface A plurality of light-emitting regions are defined thereon; a plurality of light sources are arranged in an arc shape or a U-shape, each light source is placed in its corresponding opening, and each light source emits a light from its corresponding opening The light incident surface is incident on the light guide plate; and a plurality of light redirecting structures are disposed on the back surface for guiding the light directed to the plurality of light redirecting structures to the front surface, and the Wait for the light exit area to shoot. The backlight device of claim 1, wherein the light sources of the light sources arranged at both ends of the light sources have higher luminous intensity than the light sources of the other light sources. The backlight device of claim 1, wherein the openings are also arranged in the arc shape or the U-shape, the light guide plate has a long side and a short side, and the openings are arranged in the arc shape or the U-shape. One of the center points falls substantially on one of the long sides. The backlight device of claim 1, wherein the light sources comprise a plurality of external light sources and an internal light source, the external light sources being arranged along an arc or a U-shape, the arc or the U-shaped arrangement having a first The end light source is disposed in the outer light source and is adjacent to the first end position and emits light toward the second end position. The backlight device of claim 4, wherein the second end position is not provided Set any external light source. The backlight device of claim 1, wherein the light guide plate further has a trench and a dark region, the dark region being adjacent to the side and away from the openings, conducting in the light guide plate and directed toward the trench The light is directed to the dark area. The backlight device of claim 1, further comprising a light shielding film, the light shielding film having a plurality of light transmitting portions, each of the light transmitting portions corresponding to one light emitting region, wherein the light shielding film is disposed on the light guiding plate On the front. The backlight device of claim 1, wherein the plurality of light redirecting structures are located below the plurality of light exiting regions. An illuminated keyboard comprising: a keyboard portion; and a backlight device according to any one of claims 1 to 8, disposed below the keyboard portion. The illuminated keyboard of claim 9, wherein the keyboard portion includes a multiple key, and the openings are located below the multiple key. The illuminated keyboard of claim 10, wherein the multiple key is a blank key. The illuminated keyboard of claim 10, wherein the blank key has an intermediate portion, the openings being located below the intermediate portion of the blank key. The illuminated keyboard of claim 9, wherein the keyboard portion comprises a multiple key, a numeric keypad, and at least one function key, the at least one function key being disposed between the multiple key and the numeric keypad and in close proximity thereto A multiple key, the openings being located below the edge of the at least one function key and the multiple key.