CN116299833A

CN116299833A - Backlight module

Info

Publication number: CN116299833A
Application number: CN202310136570.2A
Authority: CN
Inventors: 古士永; 许文明; 古佑铨
Original assignee: Huaian Darfon Electronics Co ltd; Darfon Electronics Corp
Current assignee: Huaian Darfon Electronics Co ltd; Darfon Electronics Corp
Priority date: 2020-02-18
Filing date: 2020-07-27
Publication date: 2023-06-23
Also published as: CN113341496A; CN113341496B

Abstract

The invention discloses a backlight module, which comprises a light guide structure, wherein the light guide structure is formed by a material of a first light medium and is provided with a light incident surface and a light diffusion structure, and the light diffusion structure is positioned at the inner side of the light guide structure and comprises at least one hollow structure. The hollow structure forms a space for accommodating a second optical medium, and the first optical medium is different from the second optical medium. The other backlight module comprises a light guide structure, wherein the light guide structure comprises a light guide part, the light guide part extends along the extending direction and is provided with a first bending part, a second bending part, a light incident surface, a first reflecting surface and a second reflecting surface in the direction perpendicular to the extending direction, the first reflecting surface is positioned at the first bending part and faces the light incident surface, and the second reflecting surface is positioned at the first bending part and faces the first reflecting surface. The invention can generate the effects of light reduction and light mixing by utilizing the hollow structure or the internal reflecting surface, thereby improving the light intensity distribution of the backlight provided by the light guide structure.

Description

Backlight module

The invention relates to a divisional application of an invention patent with the application number of 202010729820.X, the application date of 2020, 7, 27 days and the name of 'backlight module'.

Technical Field

The present invention relates to a backlight module, and more particularly to a backlight module with a light guiding structure.

Background

Backlight modules are commonly used to provide device backlight, and point light sources are commonly used. When the light guide member of the backlight module is smaller, for example, the light guide member extends in a strip shape, the light incident surface and the light emergent surface of the light guide member are positioned at two sides of the extending direction, and light enters the light guide plate through the light incident surface and exits the light guide plate through the light emergent surface. The light guide piece is difficult to mix light effectively, so that the backlight provided by the backlight module is obviously uneven and even obvious light spots are generated. In order to make the backlight uniform, the distance between the light emitting surface of the backlight module and the backlight projection target is generally increased, or the size of the light guiding plate of the backlight module is increased or a plurality of optical films, such as prism sheets, diffusion sheets, reflection sheets, etc., are stacked thereon, so as to increase the light mixing effect. The former increases the space required for arranging the light emitting module, and the latter increases the volume of the backlight module itself. In either case, the size of the device equipped with the backlight module is not easily reduced.

Disclosure of Invention

In view of the foregoing problems in the prior art, an object of the present invention is to provide a backlight module, in which a light guide structure of the backlight module utilizes a hollow structure to improve the light intensity distribution of the backlight provided by the backlight module.

In order to achieve the above objective, the present invention provides a backlight module, comprising: the light guide structure is formed by a material of a first optical medium and is provided with a first light incident surface and a light diffusion structure, the light diffusion structure is positioned at the inner side of the light guide structure and comprises at least one first hollow structure, the at least one first hollow structure forms a space for accommodating a second optical medium, and the first optical medium is different from the second optical medium.

As an optional technical solution, the at least one first hollow structure is adjacent to the first light incident surface.

As an optional technical scheme, the backlight module further comprises a light source, wherein the light source is adjacent to the first light incident surface, the light emitting direction of the light source faces the first light incident surface, and the light emitted by the light source enters the light guide structure through the first light incident surface and is changed in travelling direction by the light diffusion structure.

As an alternative solution, the at least one first hollow structure includes a through hole, and the through hole is formed by a plurality of continuous walls of the light guiding structure.

As an alternative solution, the first light incident surface is formed with a through groove, and the through groove is recessed toward the through hole.

As an optional technical solution, the at least one first hollow structure includes a plurality of triangular prism through holes, the plurality of triangular prism through holes are arranged along a reference arc segment, the reference arc segment has a notch, and the notch faces the first light incident surface.

Alternatively, the at least one first hollow structure comprises a slot formed by a plurality of continuous walls of the light guiding structure.

Alternatively, the slot has an extended path that is arcuate or angular.

Alternatively, the arc or the angle is provided with a notch, and the notch faces the first light incident surface; alternatively, the slot is crescent shaped.

As an alternative solution, the light guiding structure has a surface, the surface is adjacent to the first light incident surface and extends substantially perpendicular to the first light incident surface, the at least one first hollow structure includes a recess, the recess is concavely formed from the surface toward the inner side of the light guiding structure, and the recess has a plurality of continuous walls of the light guiding structure.

As an optional technical scheme, the inner side of the light guiding structure is provided with a light source accommodating groove, and the first light incident surface is a side surface of the light source accommodating groove.

As an optional technical scheme, the light source accommodating groove is provided with a second light incident surface, and the second light incident surface is opposite to the first light incident surface.

As an optional technical scheme, the backlight module further comprises at least one first light source and at least one second light source, wherein the at least one first light source and the at least one second light source are alternately arranged in the light source accommodating groove, the light emitting direction of the at least one first light source faces the first light incident surface, and the light emitting direction of the at least one second light source faces the second light incident surface.

As an alternative technical scheme, the backlight module further comprises a first light source and a second light source, wherein the inner side of the light guide structure is provided with a first light source accommodating groove and a second light source accommodating groove, the first light source accommodating groove and the second light source accommodating groove are arranged on two sides of the reference axis in a staggered manner along the reference axis, the first light incident surface is a side surface of the first light source accommodating groove adjacent to the reference axis, the second light incident surface is a side surface of the second light source accommodating groove adjacent to the reference axis, the first light source is arranged in the first light source accommodating groove, the second light source is arranged in the second light source accommodating groove, the light emitting direction of the first light source faces the first light incident surface, and the light emitting direction of the second light source faces the second light incident surface.

Therefore, in the backlight module, the at least one hollow structure can change the advancing direction and intensity of light, so that the light intensity distribution of the backlight provided by the light guide structure is improved.

In addition, the invention also provides another backlight module, which comprises: the light guide structure is formed by materials of a first light medium and comprises a first light guide part and a second light guide part, the first light guide part and the second light guide part are arranged along the arrangement direction, the first light guide part extends along a first extending direction, the second light guide part extends along a second extending direction, the first extending direction and the second extending direction are not parallel to each other and are perpendicular to the arrangement direction, the light guide structure is provided with a first light incident surface, a second light incident surface, a light emergent surface and a light diffusion structure, the first light incident surface is positioned on the first light guide part, the second light incident surface is positioned on the second light guide part, the light emergent surface extends along the arrangement direction, the light diffusion structure is positioned on the inner side of the first light guide part and comprises at least one first hollow structure, each first hollow structure forms a space for accommodating the second light medium, and the first light medium is different from the second light medium.

As an optional technical solution, the light diffusion structure further includes at least one second hollow structure, and the at least one second hollow structure is located inside the second light guiding portion.

Alternatively, the at least one first hollow structure extends perpendicular to the first extending direction, and the at least one second hollow structure extends obliquely to the second extending direction.

Therefore, in the backlight module, the light emitted by the light sources which are not arranged on the same plane can be guided by the first light guide part and the second light guide part, and the light can be emitted out of the light guide structure through the same light emitting surface, so that the capability of adapting to surrounding structures of the light guide structure can be improved. The at least one hollow structure can change the advancing direction and intensity of the light, so that the light intensity distribution of the backlight provided by the light guide structure is improved.

Another objective of the present invention is to provide a backlight module, in which the light guide structure uses a plurality of internal reflection surfaces to increase the light traveling path, so as to improve the light intensity distribution of the backlight provided by the backlight module.

Therefore, the invention also provides a backlight module, comprising: the light guide structure comprises a first light guide part, wherein the first light guide part extends along an extending direction and is provided with a first bending part, a second bending part, a light incident surface, a first reflecting surface and a second reflecting surface in a direction perpendicular to the extending direction, the first reflecting surface is positioned at the first bending part and faces the light incident surface, and the second reflecting surface is positioned at the second bending part and faces the first reflecting surface.

As an alternative technical scheme, the first reflecting surface and the second reflecting surface are both planes, and the first reflecting surface and the second reflecting surface are parallel or perpendicular to each other.

As an alternative solution, the light entering the first light guiding portion through the light incident surface travels in a first direction, the light is reflected by the first reflecting surface and travels in a second direction, the light is reflected by the second reflecting surface and travels in a third direction, and the first direction is opposite to or the same as the third direction.

As an alternative technical scheme, the light guiding structure includes a second light guiding portion, the second light guiding portion is in a plate structure and extends along the extending direction, and the light entering the first light guiding portion through the light incident surface is reflected by the first reflecting surface and the second reflecting surface in sequence, so as to enter the second light guiding portion.

As an optional technical scheme, the backlight module further comprises a light source device, the light source device is arranged adjacent to the light incident surface, and light rays emitted by the light source device enter the first light guide part through the light incident surface and are reflected by the first reflecting surface and the second reflecting surface in sequence.

As an optional technical solution, the first light guiding portion includes a first sub-portion, a second sub-portion and a third sub-portion, the second sub-portion is connected with the first sub-portion and the third sub-portion, the first sub-portion includes the light incident surface, the light source device includes a circuit board and a plurality of light sources, the first sub-portion and the third sub-portion are located at two sides of the circuit board, the plurality of light sources are fixed on the circuit board, and a light emitting direction of the plurality of light sources faces the light incident surface.

As an optional technical solution, the light source device includes a plurality of light sources, the plurality of light sources are disposed adjacent to the light incident surface, the light emitting directions of the plurality of light sources are different and face the light incident surface, and the plurality of light sources emit different color lights.

Therefore, in the backlight module, the light entering the light guide part through the light incident surface is reflected by the first reflecting surface and the second reflecting surface in sequence, so that the path length of the light traveling in the light guide structure can be increased, the light mixing effect is increased, and the light intensity distribution of the backlight provided by the light guide structure is improved.

Compared with the prior art, the backlight module can generate the dimming and mixing effects by utilizing the hollow structure or the internal reflecting surface, so that the light intensity distribution of the backlight provided by the light guide structure is improved, and the backlight module can solve the problem that the prior art is difficult to reduce the volume of the backlight module or the device provided with the backlight module for maintaining the uniformity of the backlight without increasing the structural size.

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

The invention will now be described in more detail with reference to the drawings and specific examples, which are not intended to limit the invention thereto.

Drawings

Fig. 1 is a schematic diagram of a backlight module according to an embodiment.

Fig. 2 is a top view of the backlight module in fig. 1.

Fig. 3 is an enlarged view of a hollow structure of the light diffusing structure in fig. 2.

Fig. 4 is an enlarged view of a variation of the hollow structure of fig. 3.

Fig. 5 is a top view of a hollow structure of a light diffusing structure according to an embodiment.

Fig. 6 is a top view of a hollow structure of a light diffusing structure according to an embodiment.

Fig. 7 is a cross-sectional view taken along line X-X of fig. 6.

Fig. 8 is a top view of a backlight module according to an embodiment.

Fig. 9 is a top view of a backlight module according to another embodiment.

Fig. 10 is a top view of a backlight module according to another embodiment.

Fig. 11 is a schematic diagram of a backlight module according to an embodiment.

Fig. 12 is a cross-sectional view of the backlight module of fig. 11 along the line Y-Y.

Fig. 13 is a cross-sectional view of a backlight module according to an embodiment.

Fig. 14 is a schematic diagram of structural logic of a first light guide portion according to an embodiment.

Fig. 15 is an exploded view of a backlight module according to an embodiment.

Fig. 16 is a bottom view of the backlight module of fig. 15.

Fig. 17 is a schematic diagram of a backlight module according to another embodiment.

Fig. 18 is a cross-sectional view of the backlight module of fig. 17 along the line Z-Z.

Fig. 19 is a cross-sectional view of the backlight module of fig. 17 along the line W-W.

Detailed Description

For a further understanding of the objects, construction, features, and functions of the invention, reference should be made to the following detailed description of the preferred embodiments.

Please refer to fig. 1 and 2. The backlight module 1 according to an embodiment includes a light guiding structure 12 and a light source device 14. The light guiding structure 12 is formed of a material of a first optical medium (for example, but not limited to, a light-permeable polymer material, for example, by injection molding), and the light guiding structure 12 has a light incident surface 122 and a light diffusing structure 124 (the range of which is shown in the figure with a dashed frame), and the light diffusing structure 124 is located inside the light guiding structure 12 and includes a plurality of hollow structures 1242. When the backlight module 1 is applied to a keyboard, the extending direction of the light incident surface 122 generally corresponds to the long side or the short side of the whole rectangular keyboard (not shown). The hollow structure 1242 forms a space (e.g., without limitation, accommodating air) accommodating a second optical medium, the first optical medium being different from the second optical medium. The light source device 14 includes a circuit board 142 (such as, but not limited to, a printed circuit board, a flexible printed circuit board, etc.) and a plurality of light sources 144 (such as, but not limited to, light emitting diodes) disposed thereon. The light sources 144 are disposed corresponding to the hollow structures 1242 and face the light incident surface 122, such that light rays (indicated by thin line arrows in fig. 2) emitted by the light sources 144 enter the light guiding structure 12 through the light incident surface 122. The light entering the light guiding structure 12 changes the traveling direction via the light diffusing structure 124, so that the light guiding structure 12 has a light mixing effect. In addition, the intensity of the light passing through the hollow structure 1242 is reduced in principle, so that the hollow structure 1242 also has an effect of adjusting the light intensity distribution.

In the present embodiment, the light guiding structure 12 has a plate-like structure, the light incident surface 122 is located at a side edge of the light guiding structure 12 and extends along an extending direction D1 (indicated by a double arrow), the circuit board 142 also extends along the extending direction D1, and the light sources 144 are also arranged along the extending direction D1 and the light emitting direction 144a (indicated by an arrow) thereof faces the light incident surface 122; the light emitting direction 144a is perpendicular to the extending direction D1, but the present invention is not limited thereto. The hollow structures 1242 are disposed adjacent to the light incident surface 122 and the corresponding light sources 144, so as to increase the light diffusing and light intensity weakening effects of the hollow structures 1242, and facilitate the backlight module 1 to provide a uniform backlight. For the strip-shaped light guide structure (extending along the extending direction D1), the above structure configuration can also provide a good light intensity distribution improving effect, which is beneficial to reducing the volume of the backlight module.

Please refer to fig. 3. In the present embodiment, the hollow structure 1242 is a slot, the extending direction of the slot is substantially perpendicular to the extending direction D1 and the light emitting direction 144a, and the hollow structure 1242 penetrates the light guiding structure 12. The slot is formed by a plurality of continuous walls 12420 of the light guide structure 12 (e.g., connected in a ring) and has an extended path 1242a (shown in phantom in fig. 3). The extending path 1242a has an angle shape with a notch facing the light incident surface 122, and the corresponding light source 144 is disposed towards the notch. The slots in principle provide refraction and reflection of light entering the light guide structure 12 and thereby provide light diffusion and weakening effects of the light after passing through. In addition, in the present embodiment, the angle forms an included angle 1242b, and the included angle 1242b is between, for example, but not limited to, 90 degrees to 140 degrees. Also, the angle has a side length 1242c, the side length 1242c being approximately, for example, but not limited to, 3.9mm. In practice, the extended path 1242a of the slot may have other geometric structures, such as an arc shape; at this time, the arc has a notch facing the light incident surface 122, which also has the effect of diffusing and reducing light. In addition, in practical operation, the light incident surface 122 may have a wave structure (shown in fig. 3 by dotted lines, for example, it may be formed simultaneously when the light guide structure 12 is injection molded), which may increase the diffusion effect. In addition, in the present embodiment, the slot width (along the extension path 1242 a) of the hollow structure 1242 is constant, but may be changed in practical operation, for example, the hollow structure 1242 is modified to be wider at the middle and narrower at the two sides, and the hollow structure 1242' as shown in fig. 4 is in a crescent shape. The hollow structure 1242' also has light diffusing and light-reducing effects.

In addition, in practice, the slots penetrating the light guide structure 12 may be replaced by other penetrating structures. As shown in fig. 5, the light diffusing structure 125 according to an embodiment includes a plurality of hollow structures 1252, and at least one hollow structure 1252 includes a plurality of triangular prism-shaped through holes 1252a. Each triangular-cylindrical through hole 1252a is formed by connecting three continuous walls. The plurality of triangular-cylindrical through holes 1252a are arranged along a reference arc 1252b (shown in chain lines in fig. 5). The reference arc 1252b has a notch facing the light incident surface 122. In this embodiment, reference arc 1252b has a center 1252c (shown in FIG. 5 with a cross-shaped label). Each triangular-cylindrical through hole 1252a has a long edge 1252d (projected as a point in fig. 5) perpendicular to the reference arc 1252 b. Each triangular prism shaped through-hole 1252a defines a direction 1252e (represented by an arrow in fig. 5), the direction 1252e passing through the long edge 1252d of the corresponding triangular prism shaped through-hole 1252a and pointing towards the center 1252c. The directions 1252e of two adjacent triangular-cylindrical through holes 1252a form an included angle 1252f, and the included angle 1252f is about, for example, but not limited to, 21 degrees. The corresponding light sources 144 (shown in fig. 5 with a dashed box) are disposed towards the light incident surface 122 and the plurality of triangular prism-shaped through holes 1252a (or the light diffusing structures 125).

In addition, in the present embodiment, the light incident surface 122 forms a through groove 122a, and the through groove 122a is recessed toward the light diffusion structure 125. The light source 144 is disposed toward the penetration groove 122 a. The cross section of the through groove 122a is substantially semicircular and has a cross section radius 122b, and the cross section radius 122b is three times the distance 1252g between the corresponding light diffusion structure 125 and the through groove 122a, for example, the distance 1252g is 1mm, and the cross section radius 122b is 3mm, but the invention is not limited thereto in practical operation. In this embodiment, the center of the circle corresponding to the section radius 122b coincides with the center 1252c of the reference arc segment 1252b, and the light source 144 is located approximately on the center 1252 c. In addition, in practical operation, the number of the triangular-pillar shaped through holes 1252a in the hollow structure 1252 is not limited to three, for example, the hollow structure 1252 includes one or more triangular-pillar shaped through holes 1252a. The hollow structure 1252 may be implemented with one or more through holes having the same or different polygonal cross-sections, and has the same diffusion and dimming effects.

The

hollow structures

1242, 1242', 1252 in the foregoing embodiments are all implemented as penetrating structures, but are not limited to these structures in practical operation. For example, the

hollow structures

1242, 1242', 1252 are instead blind via structures having a depth (e.g., a thickness greater than 1/3, 1/2, 2/3, 4/3, etc. of the plate-like light guiding structure 12), which still have a degree of diffusion and dimming effect. As another example, as shown in fig. 6 and 7, the light diffusing structure 126 according to an embodiment includes a plurality of hollow structures 1262. The light guiding structure 12 has a surface 120a (shown as a bottom surface 120a in this embodiment), and the surface 120a is adjacent to the light incident surface 122 and extends substantially perpendicular to the light incident surface 122. Hollow structure 1262 comprises recess 1262a, recess 1262a being recessed from surface 120a towards the inside of light guiding structure 12, i.e. formed by a plurality of continuous walls of light guiding structure 12. The corresponding light source 144 (shown in phantom) is disposed toward the light incident surface 122 and the recess 1262 a. Similar to the

hollow structures

1242, 1252 described above, the recesses 1262a may in principle provide refraction and reflection for light entering the light guiding structure 12, and thereby provide light spreading effects, and also attenuate the intensity of light passing through the hollow structure 1262. In practice, the depth 1262b of the recess 1262a is greater than one third of the thickness 120b of the light guiding structure 12, so as to provide good light diffusion effect. In addition, in the present embodiment, the projection section of the recess 1262a in the direction perpendicular to the extending direction D1 and the light emitting direction 144a is rectangular, but the present invention is not limited thereto, and may be, for example, circular, polygonal, etc., and may be the same as the projection section of the

hollow structures

1242, 1252 in the direction perpendicular to the extending direction D1 and the light emitting direction 144a, and the description thereof is omitted. Of the plurality of continuous wall surfaces constituting the hollow structure 1262, the wall surfaces of the front and rear low beams and the wall surface of the high beam along the light emitting direction 144a may be disposed at an acute angle or an obtuse angle without being parallel to the light incident surface 122; in other words, the angles between the low beam wall and the high beam wall and the light incident surface 122 are respectively selected from an acute angle, an obtuse angle or a combination of 0 degrees (parallel to each other).

In the foregoing embodiments, the light source 144 is disposed outside the light guiding structure 12, but the present invention is not limited thereto. As shown in fig. 8, the backlight module 3 according to an embodiment has substantially the same structure as the backlight module 1, and the backlight module 3 basically uses the reference numerals of the backlight module 1, so for other description of the backlight module 3, please refer to the related description of the backlight module 1 and its variation, and the description is omitted. The difference between the backlight module 3 and the backlight module 1 is mainly that the light source device 14 of the backlight module 3 is disposed at a position corresponding to the light guiding structure 12. In the backlight module 3, the light guiding structure 32 has a light source accommodating groove 322, one side surface (also referred to as a wall surface) of the light source accommodating groove 322 is taken as a first light incident surface 322a, and the circuit board 142 (the hidden outline of which is shown in the drawing with a dashed line) is disposed corresponding to the light source accommodating groove 322, such that the plurality of light sources 144 are accommodated in the light source accommodating groove 322 and face the first light incident surface 322a. When the backlight module 3 is applied to a keyboard, the shape of the light guiding structure 32 corresponds to four sides of a rectangular keyboard (not shown), the extending direction of the first light incident surface 322a in fig. 8 is parallel to the short side of the keyboard, and the light source accommodating groove 322 is adjacent to the light guiding structure 32 and the short side of the rectangular keyboard.

In the present embodiment, the light source accommodating groove 322 is disposed adjacent to one side of the light guiding structure 32, and the light source 144 emits light toward the middle portion of the light guiding structure 32, but the present invention is not limited thereto. As shown in fig. 9, the backlight module 3a according to an embodiment has substantially the same structure as the backlight module 3, and the backlight module 3a basically uses the reference numerals of the backlight module 3, so that the description of the backlight module 3a is omitted herein for reference. The difference between the backlight module 3a and the backlight module 3 is mainly that the light source device 34 of the backlight module 3a is disposed at a position corresponding to the light guiding structure 12. In the backlight module 3a, the other side surface (also referred to as another wall surface) of the light source accommodating groove 322 serves as a second light incident surface 322b, and the second light incident surface 322b is opposite to the first light incident surface 322a. The light source accommodating groove 322 is located at the middle portion of the light guiding structure 32 and extends along a reference axis 322c (shown as a chain line). The light source device 34 includes a plurality of first light sources 344a and a plurality of second light sources 344b, the plurality of first light sources 344a and the plurality of second light sources 344b are disposed in the light source accommodating groove 322 along the reference axis 322c in a staggered manner, a light emitting direction (shown by an arrow) of the first light sources 344a faces the first light incident surface 322a, and a light emitting direction (shown by an arrow) of the second light sources 344b faces the second light incident surface 322b. Thus, the light source device 34 can provide light to the light guide structure 32 at the two sides of the light source accommodating groove 322 (or the reference axis 322 c), respectively.

In the present embodiment, a single light source accommodating groove 322 is used to accommodate a plurality of first light sources 344a and a plurality of second light sources 344b, but the present invention is not limited thereto. As shown in fig. 10, the backlight module 3b according to an embodiment has substantially the same structure as the backlight module 3a, and the backlight module 3b basically uses the reference numerals of the backlight module 3a, so that the description of the backlight module 3b is omitted herein for reference. The difference between the backlight module 3b and the backlight module 3a is mainly that the backlight module 3b does not use a single light source accommodating groove to accommodate the

light sources

344a, 344b. In the backlight module 3b, the inner side of the light guiding structure 33 includes a plurality of first light source accommodating grooves 332a and a plurality of second light source accommodating grooves 332b corresponding to the plurality of first light sources 344a and the plurality of second light sources 344b, respectively, i.e. the plurality of first light source accommodating grooves 332a correspond to the plurality of first light sources 344a, and the plurality of second light source accommodating grooves 332b correspond to the plurality of second light sources 344b. The first light source accommodating grooves 332a and the second light source accommodating grooves 332b are disposed along the reference axis 333c (shown in the figure as a chain line) at two sides of the reference axis 333c in a staggered manner, for example, in the view of fig. 10, the first light source accommodating grooves 332a are disposed on the right side of the reference axis 333c, and the second light source accommodating grooves 332b are disposed on the left side of the reference axis 333 c. One side surface (also referred to as a wall surface) of the first light source accommodating groove 332a facing right serves as a first light incident surface 333a, and one side surface (also referred to as a wall surface) of the second light source accommodating groove 332b facing left serves as a second light incident surface 333b. The first light sources 344a are disposed in the corresponding first light source accommodating grooves 332a, and the light emitting direction (indicated by an arrow in the figure) of the first light sources 344a faces the corresponding first light incident surface 333a, that is, the first light incident surface 333a is located at a side surface of the first light source accommodating groove 332a adjacent to the reference axis 333 c. The second light sources 344b are disposed in the corresponding second light source accommodating grooves 332b, and the light emitting direction (indicated by an arrow in the figure) of the second light sources 344b faces the corresponding second light incident surface 333b, that is, the second light incident surface 333b is located at a side of the second light source accommodating groove 332b adjacent to the reference axis 333 c. Therefore, the light source device 34 can also provide light to the portions of the light guiding structure 32 at both sides of the reference axis 322c, and the arrangement of the light source

accommodating grooves

332a, 332b (and the light sources 344a, 334 b) can also help to reduce the interference of the light guiding effect of the light guiding structure 33. In addition, in the present embodiment, the light emitting directions of the first light source 344a and the second light source 344b are parallel and opposite, but the present invention is not limited thereto. In the present embodiment, the light source

accommodating grooves

332a, 332b are implemented as through holes, but the present invention is not limited thereto. For example, the light source

accommodating grooves

332a, 332b are implemented as blind holes, so that the interference of the light guiding effect of the light guiding structure 33 by the light source

accommodating grooves

332a, 332b can be further reduced.

In the foregoing embodiments, the

backlight modules

1, 3a, 3b utilize the

hollow structures

1242, 1252, 1262 to change the traveling direction and intensity of the light in the

light guiding structures

12, 32, 33, so that the

backlight modules

1, 3a, 3b can provide more uniform backlight. However, the present invention is not limited to this, and the light mixing effect can be increased by increasing the path length of the light traveling in the light guiding structure. Please refer to fig. 11 and 12. The backlight module 5 according to an embodiment includes a light guiding structure 52 and a light source device 54. The light guiding structure 52 includes a first light guiding portion 522, the first light guiding portion 522 has a light incident surface 5222, a first reflecting surface 5224, a second reflecting surface 5226 and a light emitting surface 5228, the first reflecting surface 5224 faces the light incident surface 5222, and the second reflecting surface 5226 faces the first reflecting surface 5224 and the light emitting surface 5228. The light source device 54 includes a circuit board 542 (such as, but not limited to, a printed circuit board, a flexible printed circuit board, etc.) and a plurality of light sources 544 (such as, but not limited to, light emitting diodes) disposed thereon. The plurality of light sources 544 are disposed adjacent to the light incident surface 5222. Light emitted by the light source 144 (shown by thin line arrows) enters the first light guiding portion 522 through the light incident surface 5222, and the light entering the light guiding structure 12 changes the traveling direction through the light diffusing structure 124, so as to enhance the light mixing effect of the light guiding structure 12 on the light. And is reflected by the first reflecting surface 5224 and the second reflecting surface 5226 in sequence.

In the present embodiment, the first light guiding portion 522 has a stripe structure and extends along an extending direction D2 (indicated by a double arrow in fig. 11), the light incident surface 5222 extends along the extending direction D2, the circuit board 542 also extends along the extending direction D2, the plurality of light sources 544 are also arranged along the extending direction D2, and the light emitting direction 544a thereof (indicated by an arrow in the figure) faces the light incident surface 5222; however, the light emitting direction 544a is not limited to this in practice, and is perpendicular to the extending direction D2.

In the present embodiment, the projection cross section of the first light guiding portion 522 in the extending direction D2 is zigzag, that is, the first light guiding portion 522 has a first bending portion 5220a and a second bending portion 5220b in a direction perpendicular to the extending direction D2, the first reflecting surface 5224 is located at the first bending portion 5220a, and the second reflecting surface 5226 is located at the second bending portion 5220b. The light entering the first light guiding portion 522 through the light incident surface 5222 travels in a first direction d1 (indicated by an arrow in fig. 12). The light ray travels in a second direction d2 (shown by an arrow in fig. 12) after being reflected by the first reflecting surface 5224. The light ray travels in a third direction d3 (shown by an arrow in fig. 12) after being reflected by the second reflecting surface 5226. The first direction d1 is the same as the third direction d 3. In the present embodiment, the first reflective surface 5224 and the second reflective surface 5226 are planar surfaces, and the two planar surfaces are parallel to each other, but the present invention is not limited thereto. For example, the first reflective surface 5224 and the second reflective surface 5226 can be slightly non-parallel and form an included angle therebetween. For another example, the first reflective surface 5224 and/or the second reflective surface 5226 can be curved.

In addition, in the present embodiment, the light guiding structure 52 further includes a second light guiding portion 524, and the second light guiding portion 524 has a plate-like structure. The light entering the first light guiding portion 522 through the light incident surface 5222 is reflected by the first reflecting surface 5224 and the second reflecting surface 5226 in sequence, and exits the first light guiding portion 522 from the light emergent surface 5228 to enter the second light guiding portion 524. In actual operation, the first light guiding portion 522 and the second light guiding portion 524 may be integrally formed; at this time, the light-emitting surface 5228 is virtually disappeared.

As shown in fig. 12, the first light guide portion 522 includes a first sub-portion 522a, a second sub-portion 522b, and a third sub-portion 522c, and the second sub-portion 522b connects the first sub-portion 522a and the third sub-portion 522c. The first sub-portion 522a includes a light incident surface 5222, the first reflective surface 5224 (and the first bending portion 5220 a) is located at a connection between the first sub-portion 522a and the second sub-portion 522b, and the second reflective surface 5226 (and the second bending portion 5220 b) is located at a connection between the second sub-portion 522b and the third sub-portion 522c. The light enters the first sub-portion 522a through the light incident surface 5222 and travels in the first direction d 1. Then, the light is reflected by the first reflecting surface 5224 to enter the second subsection 522b and travel in the second direction d 2. Then, the light is reflected by the second reflecting surface 5226 to enter the third sub-portion 522c and travel in the third direction d 3. In addition, the first sub-portion 522a and the third sub-portion 522c are located at two sides of the second direction d2, so that the first light guiding portion 522 has a zigzag structure, and the first direction d1 is the same as the third direction d 3. The first sub-portion 522a and the third sub-portion 522c are located at two sides of the circuit board 542 in the second direction d2, which helps to reduce the thickness of the backlight module 5 in the second direction d 2.

In addition, in practical operation, the structure of the first light guiding portion 522 may be modified to further reduce the size of the backlight module 5. For example, as shown in fig. 13, the backlight module 5a according to another embodiment is similar to the backlight module 5 in structure, and the backlight module 5a basically uses the reference numerals of the backlight module 5, so for other description of the backlight module 5a, please refer to the related description of the backlight module 5 and its variation, and the description is omitted. The difference between the backlight module 5a and the backlight module 5 is that, in the first light guiding portion 532 of the light guiding structure 53 of the backlight module 5a, the first sub-portion 522a and the third sub-portion 522C are located at the same side of the second direction d2 (or the second sub-portion 522 b), so that the first light guiding portion 532 has an inverted C-shaped structure, and the first reflective surface 5224 and the second reflective surface 5226 are located at the turning positions of the inverted C-shape (i.e., the first and

second bending portions

5220a and 5220 b), and the first direction d1 is opposite to the third direction d 3. Similarly, the first sub-portion 522a and the third sub-portion 522c are also located on two sides of the circuit board 542 in the second direction d2, which helps to reduce the thickness of the backlight module 5a in the second direction d 2. Also, the first sub-portion 522a and the third sub-portion 522c are located at the same side of the second direction d2 (or the second sub-portion 522 b), which helps to reduce the width of the backlight module 5a in the direction perpendicular to the second direction d 2. In addition, in the present embodiment, the first reflective surface 5224 and the second reflective surface 5226 are both planes, and the two planes are perpendicular to each other, but the present invention is not limited thereto. For example, the first and second

reflective surfaces

5224, 5226 can be slightly non-perpendicular forming an acute or obtuse angle therebetween that is approximately a right angle. For another example, the first reflective surface 5224 and/or the second reflective surface 5226 can be curved.

In addition, in the foregoing embodiments, the directions d1, d2, d3 in which the light travels in the

light guiding structures

52, 53 are common, but the present invention is not limited thereto. For example, as shown in fig. 14, the first sub-portion 522a, the second sub-portion 522b, and the third sub-portion 522c of the first light guiding portion 533 according to an embodiment are configured in a three-dimensional structure logically. For simplicity of illustration, the first light guide portion 533 follows the reference numeral of the first light guide portion 522. In this embodiment, the first direction d1 is non-parallel to the third direction d3, for example, the first direction d1, the second direction d2 and the third direction d3 are perpendicular to each other. This helps to increase the design flexibility of the first light guide portion 533.

In the foregoing embodiments, the light incident surface 5222 is substantially flat, but the present invention is not limited thereto. For example, as shown in fig. 15 and 16, the backlight module 5b according to another embodiment is similar to the backlight module 5 in structure, and the backlight module 5b basically uses the reference numerals of the backlight module 5, so that the description of the backlight module 5b is omitted herein for reference. The difference between the backlight module 5b and the backlight module 5 is that the light sources 544 of the backlight module 5b are disposed in different

light emitting directions

544a, 544b, 544c (shown by arrows in fig. 16) toward the light incident surface 5522 of the first light guiding portion 552 of the light guiding structure 55; the plurality of

light emitting directions

544a, 544b, 544c are radially distributed, which also helps to diffuse light. In the present embodiment, each three light sources 544 is a group, and each emits different color light, such as but not limited to red light, green light, and blue light; in practical applications, other numbers of light sources may be used to group the plurality of light sources 544, which is not described herein. In addition, in the present embodiment, the light incident surface 5522 also includes

light incident regions

5522a, 5522b, 5522c with different directions corresponding to the arrangement direction of the light sources 544 (or the

light emitting directions

544a, 544b, 544 c), such that the light emitted by each light source 544 is still substantially perpendicularly incident to the light incident surface 5522 (or the corresponding

light incident regions

5522a, 5522b, 5522 c).

As described above, the

backlight module

5, 5a, 5b reflects the light by the

reflective surface

5224, 5226 inside the

light guiding structure

52, 53, 55, so that the light can travel along the extending path of the

light guiding structure

52, 53, 55, so as to increase the path length of the light traveling in the

light guiding structure

52, 53, 55, thereby increasing the light mixing effect, which is also helpful for improving the uniformity of the backlight provided by the

backlight module

5, 5a, 5 b.

In addition, in the

backlight modules

1, 3a,3b, 5a, 5b, the

light sources

144, 344a, 344b, 544 are disposed substantially on the same plane and emit light parallel to the same plane, for example, in the

light guiding structures

12, 522, only the

light incident surface

122, 5222 is single, but the present invention is not limited thereto. For example, it may be desirable to have light enter from multiple light entrance surfaces because of the avoidance of specific components such as cable exit structures, or because of design aesthetics. However, when the light comes from the light incident surfaces and finally comes out together in the same flat plane (for example, the light emergent surface extends corresponding to the long side of the keyboard), the problems of brightness difference and non-uniformity of mixed light on each light emergent surface need to be solved.

As shown in fig. 17 to 19, the backlight module 7 includes a light guiding structure 72, a first light source device 74 and a second light source device 76. The light guiding structure 72 has a first light guiding portion 722 and a second light guiding portion 724, where the first light guiding portion 722 and the second light guiding portion 724 are arranged along an arrangement direction D3 and extend along a first extending direction D4 and a second extending direction D5, respectively, and specifically, the first light guiding portion 722 extends along the first extending direction D4 and the second light guiding portion 724 extends along the second extending direction D5; the arrangement direction D3, the first extending direction D4, and the second extending direction D5 are indicated by double arrows. The first extending direction D4 and the second extending direction D5 are not parallel to each other and are perpendicular to the arrangement direction D3. The first light source device 74 and the second light source device 76 are disposed corresponding to the first light guide portion 722 and the second light guide portion 724, respectively, such that the light emitted by the first light source device 74 and the second light source device 76 enter the light guide structure 72 through the first light guide portion 722 and the second light guide portion 724, respectively.

In the present embodiment, the first light guiding portion 722 has a plurality of first light incident surfaces 7222 implemented by a plurality of holes; correspondingly, the first light source device 74 includes a circuit board 742 and a plurality of light sources 744 disposed thereon, the light sources 744 are disposed in the holes to face the corresponding first light incident surfaces 7222, and the light emitting directions of the light sources 744 are shown by an arrow in fig. 18. Thereby, the light emitted by the light source 744 enters the first light guiding portion 722 through the first light incident surface 7222. The light sources 744 and the first light incident surfaces 7222 corresponding to the light sources are arranged along the arrangement direction D3, and the arrangement direction D3 is perpendicular to the first extending direction D4. Also, the second light guide portion 724 has a plurality of second light incident surfaces 7242 implemented by a plurality of recesses formed at one side of the second light guide portion 724; correspondingly, the second light source device 76 includes a circuit board 762 and a plurality of light sources 764 disposed thereon, wherein the plurality of light sources 764 are disposed in the plurality of recesses respectively to face the corresponding second light incident surface 7242, and the light emitting directions of the light sources 764 are shown by arrows in fig. 19. The light sources 764 and the second light incident surfaces 7242 corresponding to the light sources are also arranged along the arrangement direction D3, and the arrangement direction D3 is perpendicular to the second extending direction D5. Thereby, the light emitted by the light source 764 enters the second light guiding portion 724 through the second light incident surface 7242. In addition, the light guiding structure 72 has a light emitting surface 726, and the light emitting surface 726 extends straight along the arrangement direction D3, for example, along the long side or the short side of the keyboard. Light entering the light guiding structure 72 through the first light guiding portion 722 and the second light guiding portion 724 respectively will commonly exit the light guiding structure 72 through different partial sections of the same light exit surface 726.

In the present embodiment, the inner side of the first light guiding portion 722 includes a plurality of first hollow structures 7224, and the plurality of first hollow structures 7224 correspond to the plurality of first light incident surfaces 7222. The first hollow structure 7224 extends perpendicular to the first extending direction D4. The first hollow structure 7224 is a blind hole structure, and has a light-reducing effect; in practice, the first hollow structure 7224 can also be implemented by other structures (including structure extension direction, geometry, etc.), such as the

hollow structures

1242, 1252, 1262 and their variations as described above. Similarly, the inner side of the second light guiding portion 724 includes a plurality of second hollow structures 7244, and the plurality of second hollow structures 7244 correspond to the plurality of second light incident surfaces 7242. The second hollow structure 7244 extends obliquely to the second extending direction D5. The second hollow structure 7244 is a blind hole structure, and has diffusion and dimming effects; in practice, the first hollow structure 7224 can also be implemented by other structures (e.g., having different structure extension directions, geometric shapes, etc.), such as the

hollow structures

1242, 1252, 1262 and variations thereof described above. In addition, in the present embodiment, the surfaces of the first light incident surface 7222 and the second light incident surface 7242 are formed with diffusion structures (such as but not limited to wave structures, groove structures, etc., which may be formed simultaneously when the light guiding structure 72 is injection molded), so as to facilitate increasing the light mixing degree of the light in the light guiding structure 72. In practical applications, the first hollow structure 7224 and the second hollow structure 7244 can be designed based on the light path from the first light incident surface 7222 to the light emergent surface 726 and the light path from the second light incident surface 7242 to the light emergent surface 726, so that the backlight module 7 can provide a more uniform backlight through the light emergent surface 726. As shown in fig. 19, the second hollow structure 7244 corresponds to a partial section of the light emitting surface 726 of the second light incident surface 7242, and is located in the light emitting direction of the light source 764 or directly in front of the second light incident surface 7242; in fig. 18, the first hollow structure 7224 corresponds to a partial section of the light emitting surface 726 of the first light incident surface 7222, and is not located directly in front of the light emitting direction of the first light incident surface 7222 or the light source 744. The first light guiding portion 722 may be bent to form one or more reflective surfaces 7226, so as to guide the light from the first light incident surface 7222 to a partial section of the corresponding light emergent surface 726.

In addition, in the present embodiment, the light guiding structure 72 is also a light diffusing structure formed by the first hollow structure 7224 and the second hollow structure 7244, so that the light entering the light guiding structure 72 is adjusted (including the traveling path, the light intensity, etc.), and thus the effect of adjusting the light intensity distribution is also achieved. For other descriptions of the components of the backlight module 7, refer to the corresponding descriptions of the components of the foregoing Wen Beiguang module 1 and their variants, and the descriptions are omitted. In addition, in the present embodiment, as shown in fig. 17, the light guiding structure 72 further includes another first light guiding portion 722', and the another first light guiding portion 722' is arranged at the other side of the second light guiding portion 724 with respect to the first light guiding portion 722 along the arrangement direction D3. In practice, the backlight module 7 can be applied to an optical decoration application of the keyboard, for example, to emit light outwards along the long side of the keyboard. As shown in fig. 18, the light guiding structure 72 is sandwiched between an upper case 8a and a lower case 8b (all shown by dotted lines) of the keyboard, and the light emitting surface 726 is exposed to the keyboard. Various visual effects can be created by controlling the

light sources

744, 764 to emit light respectively. The light guiding structure 72 can adapt to the internal structure or the component configuration of the keyboard through the arrangement of the first light guiding portion 722 and the second light guiding portion 724. In practice, the light guiding structure 72 may include more light guiding portions of different structures to increase its adaptability to the internal structure or component configuration of the keyboard.

Of course, the present invention is capable of other various embodiments and its several details are capable of modification and variation in light of the present invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. The utility model provides a backlight unit which characterized in that includes:

the light guide structure is formed by a material of a first optical medium and is provided with a first light incident surface and a light diffusion structure which is arranged in parallel with the first light incident surface, the light diffusion structure is positioned at the inner side of the light guide structure and comprises at least one first hollow structure, the at least one first hollow structure forms a space for accommodating a second optical medium, and the first optical medium is different from the second optical medium;

The at least one first hollow structure comprises a slot formed by a plurality of continuous wall surfaces of the light guide structure, the slot is provided with a crescent, arc or angular extension path, the slot is provided with a notch and a convex edge opposite to the notch, the notch faces the first light incident surface, and the convex edge is far away from the first light incident surface.

2. A backlight module according to claim 1, wherein: the at least one first hollow structure is adjacent to the first light incident surface.

3. A backlight module according to claim 1, wherein: the backlight module further comprises a light source, wherein the light source is adjacent to the first light incident surface, the light emitting direction of the light source faces the first light incident surface, and the light emitted by the light source enters the light guide structure through the first light incident surface and is changed in advancing direction by the light diffusion structure.

4. A backlight module according to claim 1, wherein: the notch of the at least one first hollow structure is positioned between the convex edge corresponding to the notch and the first light incident surface.

5. A backlight module according to claim 1, wherein: the surface of the first light incident surface is provided with a diffusion structure formed by a wave structure or a groove structure.

6. A backlight module according to claim 1, wherein: the slot has a crescent-shaped extension path, the crescent-shaped slot having tapered ends.

7. A backlight module according to claim 1, wherein: the plurality of continuous wall surfaces of the at least one first hollow structure comprise a low beam wall surface arranged along the light emitting direction and a high beam wall surface opposite to the low beam wall surface, the low beam wall surface and the high beam wall surface form an arc or angle extending path, and the low beam wall surface is parallel to the high beam wall surface, or the plurality of continuous wall surfaces of the at least one first hollow structure comprise a low beam wall surface arranged along the light emitting direction and a high beam wall surface opposite to the low beam wall surface, the low beam wall surface and the high beam wall surface form a crescent, arc or angle extending path, and the low beam wall surface and the high beam wall surface are not parallel.

8. A backlight module according to claim 1, wherein: the inner side of the light guide structure is provided with a light source accommodating groove, and the first light incident surface is a side surface of the light source accommodating groove.

9. A backlight module according to claim 8, wherein: the light source accommodating groove is provided with a second light incident surface, and the second light incident surface is opposite to the first light incident surface.

10. A backlight module according to claim 9, wherein: the backlight module further comprises at least one first light source and at least one second light source, wherein the at least one first light source and the at least one second light source are arranged in the light source accommodating groove in a staggered mode, the light emitting direction of the at least one first light source faces the first light incident surface, and the light emitting direction of the at least one second light source faces the second light incident surface.

11. A backlight module according to claim 1, wherein: the backlight module further comprises a first light source and a second light source, wherein the inner side of the light guide structure is provided with a first light source accommodating groove and a second light source accommodating groove, the first light source accommodating groove and the second light source accommodating groove are arranged on two sides of the reference axis in a staggered mode along the reference axis, the first light incident surface is a side surface, adjacent to the reference axis, of the first light source accommodating groove, the second light incident surface is a side surface, adjacent to the reference axis, of the second light source accommodating groove, the first light source is arranged in the first light source accommodating groove, the second light source is arranged in the second light source accommodating groove, the light emitting direction of the first light source faces the first light incident surface, and the light emitting direction of the second light source faces the second light incident surface.

12. A backlight module according to claim 9, wherein: the backlight module further comprises at least one first light source and at least one second light source, the light diffusion structure further comprises at least one second hollow structure, the first light incident surface is located between the at least one first light source and the at least one first hollow structure, and the second light incident surface is located between the at least one second light source and the at least one second hollow structure.

13. A backlight module according to claim 12, wherein: the light emitting direction of the at least one first light source is far away from the light emitting direction of the at least one second light source.

14. The utility model provides a backlight unit which characterized in that includes:

wherein the at least one first hollow structure comprises a recess formed by a plurality of continuous wall surfaces of the light guide structure, the recess is concavely formed from the surface of the light guide structure towards the inside of the light guide structure, and the recess does not penetrate through the light guide structure;

The plurality of continuous wall surfaces of the at least one first hollow structure comprise a low beam wall surface arranged along the light emitting direction and a high beam wall surface opposite to the low beam wall surface, wherein the low beam wall surface and the first light incident surface form an included angle which is an acute angle, an obtuse angle or 0 degree; the high beam wall surface and the first light incident surface form another included angle which is an acute angle, an obtuse angle or 0 degree, and at least one of the low beam wall surface and the high beam wall surface is not parallel to the first light incident surface.

15. A backlight module according to claim 14, wherein: the low beam wall is not parallel to the high beam wall.

16. A backlight module according to claim 14, wherein: the depth of the recess is greater than one third of the thickness of the light guiding structure.