TW201712379A - Backlight module - Google Patents

Abstract

A backlight module includes a light guide plate substantially extending along X axis and Y axis, a light source having a light-emitting face for providing light toward the light guide plate, at least one film disposed on the light guide plate, and at least one adhesive layer for adhering the film and the light guide plate, wherein a projection of the light-emitting face on the X axis has a light-emitting X length; a halo space is defined by translation of the light-emitting face along the Y axis; at least a portion of the adhesive layer is located within the projection area of the halo space on the Z axis; the distance in the Y axis between the adhesive layer and the light-emitting face is 2~3 mm; a projection of the portion of the adhesive layer on the X axis has an adhesive X length smaller than the light-emitting X length.

Description

Backlight module

The present invention generally relates to a backlight module. Specifically, the present invention relates to a backlight module that reduces halation on the light exit side of a light source.

With the evolution of technology and the improvement of notebook computer specifications, the illuminated keyboard has gradually become the mainstream input device for notebook computers. The illuminated keyboard usually consists of the upper button module and the lower backlight module, and the backlight module is close to the size of the button module; thus the backlight module can be stacked and extended under the entire button module, so that the entire illuminated keyboard is in different areas. The brightness of the light remains uniform.

However, as shown in FIG. 1 , the light source 1001 of the conventional backlight module is in front of the light exiting side, usually because the optical film (for example, the light blocking film 1002 and/or the reflective sheet 1004) is not closely covered above/under the light guiding plate 1006. The surface has a gap 1008, 1009 between the upper/lower surface of the light guide plate 1006 and the light shielding film 1002 and the reflection sheet 1004, respectively, so that the light emitted from the light source 1001 enters the light guide plate 1006, and the light guide plate adjacent to the gaps 1008 and 1009 The upper/lower surface of the 1006 is dissipated away from the light guide plate 1006, which causes a serious halo phenomenon at the gaps 1008 and 1009, which in turn causes the brightness of the illuminated keyboard to perform poorly. Conversely, if the adhesive is used to bond the light guide plate and the optical film over a large area to improve the tightness between the two, the light will not be properly placed because the refractive index of the adhesive is much higher than that of the air. The inside of the light guide plate is transmitted, which causes excessive leakage of light on the surface of the light guide plate coated with the adhesive, so that the light output from the light guide plate away from the light source can be output. The brightness is significantly reduced.

Therefore, how to effectively improve the halo phenomenon without affecting the brightness, and selectively use an adhesive on a specific region of the light guide plate to eliminate the gap between the light guide plate and the optical film is one of the focuses of research and development. .

An object of the present invention is to provide a backlight module which is designed to improve the halo phenomenon of the light-emitting side of the light source by not only closely bonding the light guide plate and the optical film, but also by the unique design of the adhesive layer disposed in front of the light-emitting side of the light source. It also reduces the possibility of light leakage around the light source without significantly affecting the overall brightness performance.

In one embodiment, the present invention provides a backlight module including a light guide plate, a light source, at least one film, and at least one first adhesive layer, wherein the light guide plate has a top surface, a bottom surface, and a light incident surface, and the light guide plate substantially follows The X-axis and the Y-axis extend, and the X-axis, the Y-axis and the Z-axis are orthogonal to each other; the light source has a light-emitting surface to provide light toward the light-incident surface, the light-emitting surface extends along the X-axis, and the light-emitting surface is projected on the X-axis. The X-axis length of the light-emitting surface defines a halo space by translating the light-emitting surface along the Y-axis toward the light guide plate; at least one film is disposed on at least one of the top surface and the bottom surface; at least one first adhesive layer has at least a portion located in the halo In the Z-axis projection area of the space, the first adhesive layer is used to adhere at least one film to the light guide plate, wherein the first adhesive layer and the light-emitting surface are spaced apart from each other on the Y-axis by 2 to 3 mm, and the first adhesive layer is at least A portion of the projection on the X-axis has a first adhesive layer X-axis length, and the first adhesive layer has an X-axis length that is less than the X-axis length of the light-emitting surface.

In one embodiment, the halo space has a first X-axis boundary and a second X-axis boundary, the first adhesive layer has a first X-axis end point and a second X-axis end point, and the first adhesive layer is completely in the halo space. Within the Z-axis projection region, and the first X-axis boundary has a first spacing from the first X-axis endpoint, The second X-axis boundary has a second pitch with the second X-axis end point, and the first pitch and the second pitch are both greater than 0.5 mm and less than 1 mm.

In one embodiment, the first adhesive layer has an X-axis length of 2 mm, and the first adhesive layer has a Y-axis length of the first adhesive layer projected on the Y-axis, and the Y-axis length of the first adhesive layer is 1 mm.

In one embodiment, the at least one film comprises at least one of the reflective sheet and the light shielding sheet, and at least one adhesive layer is used to adhere the reflective surface and the bottom surface and/or to adhere the light shielding sheet and the top surface.

In one embodiment, the backlight module of the present invention further includes at least one second adhesive layer for adhering at least one film and a light guide plate, wherein the light source has a non-light emitting surface, and the second adhesive layer is adjacent to the Z-axis. a non-light emitting surface of the light source, and the first adhesive layer and the second adhesive layer together form a non-closed annular pattern, and the non-closed annular pattern surrounds the light source and the opening of the non-closed annular pattern corresponds to the light emitting surface .

In one embodiment, the second adhesive layer has three sides of a right side, a middle side, and a left side, wherein the right side extends to the right side of the light emitting surface, and the middle side extends opposite to the light emitting surface opposite to the light emitting surface. On the side, the left side extends to the left of the light emitting surface.

In one embodiment, the second adhesive layer has a U-shaped profile and a U-shaped opening, and the first adhesive layer is disposed on the corresponding U-shaped opening side.

In one embodiment, the first adhesive layer has a gap with the right side and the left side, respectively, and the light can travel in the light guide plate at corresponding gaps.

In one embodiment, the backlight module of the present invention further includes at least one second adhesive layer for adhering at least one of the film and the light guide plate, wherein the light source further has a non-light emitting surface, and the first adhesive layer includes the first adhesive layer. An adhesive portion and a second adhesive layer, the second adhesive layer surrounds the light source and connects the first adhesive portion and the second adhesive portion, and the second adhesive layer is adjacent to the non-light emitting surface and is connected to the first adhesive portion and The second adhesive portion has a gap between the first adhesive portion and the second adhesive portion, and the light can travel in the light guide plate at the corresponding gap.

1‧‧‧Backlight module

10‧‧‧Light guide plate

101‧‧‧Into the glossy surface

102‧‧‧ top surface

103‧‧‧ bottom

110‧‧‧First light source hole

20‧‧‧Light source unit

210‧‧‧Light source

210a‧‧‧Lighting surface

220‧‧‧Circuit board

30‧‧‧reflector

310‧‧‧Second light source hole

40‧‧‧shading film

40a‧‧‧ shading pattern

410‧‧‧ third light source hole

50‧‧‧First adhesive layer

50a‧‧‧First X-axis endpoint

50b‧‧‧second X-axis endpoint

510‧‧‧Part 1

520‧‧‧Part II

530‧‧‧First Adhesive

532‧‧‧Parts of the first adhesive

540‧‧‧Second Adhesive Department

542‧‧‧Part of the second adhesive

60‧‧‧Halo space

60a‧‧‧First X-axis boundary

60b‧‧‧Second X-axis boundary

70‧‧‧Second Adhesive Layer

2‧‧‧Key Module

22‧‧‧ buttons

1001‧‧‧Light source

1002‧‧‧shading film

1004‧‧‧reflector

1006‧‧‧Light guide plate

1008, 1009‧ ‧ gap

L1‧‧‧Lighting surface X-axis length

L2‧‧‧First adhesive layer X-axis length

L21‧‧‧ first adhesive X-axis length

L22‧‧‧Second adhesion X-axis length

L3‧‧‧First adhesive layer Y-axis length

L4‧‧‧The length of the first adhesive layer on the X-axis projection

G, G1, G2‧‧‧ gap

D‧‧‧ spacing

D1‧‧‧first spacing

D2‧‧‧second spacing

1 is a schematic cross-sectional view of a conventional backlight module in which a light beam travels; FIG. 2 is a schematic diagram of a backlight module and a button module according to an embodiment of the present invention; FIG. 3A to FIG. 3C are respectively a view of the present invention; FIG. 4A and FIG. 4B are partial top views of a backlight module according to another embodiment of the present invention; FIG. 5A and FIG. 5B are respectively a schematic view of a front view of a backlight module according to an embodiment of the present invention; FIG. 6A and FIG. 6B are partial top views of a backlight module according to another embodiment of the present invention.

The invention provides a backlight module for reducing the halo phenomenon of the light exiting side of the light source. The backlight module of the present invention can be applied to, for example, an illuminated keyboard, especially to an illuminated keyboard of a notebook computer, but is not limited thereto. For example, as shown in FIG. 2, the illuminated keyboard includes the backlight module 1 and the button module 2 of the present invention, wherein the backlight module 1 is disposed under the button module 2, and the button module 2 includes a plurality of buttons 22 It can be any suitable button module with a permeable keycap. In this embodiment, the light emitted by the backlight module 1 is transmitted through the permeable cap of the button 22 to form an illuminated keyboard. Embodiments of the backlight module of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 3A to FIG. 3C , in one embodiment, the backlight module includes a light guide plate 10 , The light source 210, the at least one film (for example, the reflective sheet 30 and the light shielding sheet 40) and the at least one first adhesive layer 50, wherein the light source 210 has a light emitting surface 210a to provide light to the light guide plate 10; the reflective sheet 30 is disposed on the light guide plate 10. One side (for example, the lower side) and the light shielding sheet 40 is disposed on the other side (for example, the upper side) of the light guide plate 10 with respect to the reflective sheet 30; the first adhesive layer 50 is disposed in front of the light emitting surface 210a and is used to adhere at least one film and Light guide plate 10. In this embodiment, the two first adhesive layers 50 are respectively disposed on the top surface 102 and the bottom surface 103 of the light guide plate 10 to adhere the light shielding sheet 40 to the top surface 102 of the light guide plate 10 and the adhesive reflection sheet 30 to the light guide plate 10 respectively. The bottom surface 103.

Specifically, the light source 210 is preferably a light emitting diode (LED), and particularly preferably a side emitting light emitting diode, but is not limited thereto. Furthermore, in this embodiment, the surface on which the light source 210 emits light (for example, the side surface of the light-emitting diode) is the light-emitting surface 210a. The light emitting surface 210a of the light source 210 faces the light incident surface 101 of the light guide plate 10 so that the light passes through the light incident surface 101 and is transmitted to the light guide plate 10. In this embodiment, the plurality of light sources 210 (ie, the plurality of light emitting diodes) are preferably integrated into the circuit board 220 to form an integrated light source unit 20, thereby improving assembly efficiency. The circuit board 220 is preferably a flexible circuit board, but is not limited thereto.

The light guide plate 10 is configured to receive light from the light source 210, wherein the light guide plate 10 has a top surface 102, a bottom surface 103, and a light incident surface 101. The light guide plate 10 can be a sheet made of any suitable optical material, such as an optical polymer, and extends substantially along the X and Y axes, wherein the X axis, the Y axis, and the Z axis are orthogonal to each other. In this embodiment, the Z-axis direction is the thickness direction of the light guide plate 10, and the size of the light guide plate 10 in the X-axis and Y-axis directions is preferably much larger than the dimension in the Z-axis direction, so that the light guide plate 10 is a thin plate or a thin plate. form. In this embodiment, the light guide plate 10 is a rectangular plate body, and the size thereof is preferably corresponding to the size of the button module 2, but is not limited thereto. The top surface 102 and the bottom surface 103 of the light guide plate 10 are respectively an upper surface and a lower surface of the light guide plate 10 which are arranged along the Z-axis direction and extend along the X-Y axis plane. surface. In this embodiment, the light incident surface 101 is parallel to the X-Z axis plane and connects the top surface 102 and the bottom surface 103, and the top surface 102 serves as the light exit surface of the light guide plate 10. After entering the light guide plate 10 through the light incident surface 101, the light provided by the light source 210 substantially travels along the X-Y axis plane, and travels to the light shielding sheet 40 at an opening (or a light transmitting portion) to be emitted from the top surface 102.

Furthermore, in an embodiment, as shown in FIG. 3A, a plurality of first light source holes 110 are formed in the vicinity of the middle position of the light guide plate 10, and a plurality of light sources 210 are arranged correspondingly, and can be respectively accommodated in plural numbers. In the first light source hole 110, the light incident surface 101 is such that the light guide plate 10 is parallel to the sidewall of the XZ axis plane in the first light source hole 110. Specifically, the plurality of first light source holes 110 are arranged through the light guide plate 10 along the Z axis and arranged along the X-axis direction to distinguish the light guide plate 10 from the left half and the right half, wherein the size and shape of the first light source hole 110 can be determined according to The actual demand changes to accommodate one or more light sources 210. For example, the seven first light source holes 110 are disposed along the X axis, and the seven light sources 210 are respectively disposed in the corresponding first light source holes 110 to respectively enter the light incident surface 101 of the corresponding first light source holes 110. A light guide plate 10 that provides light into both sides. In this embodiment, the first light source hole 110 is a rectangular hole, and the plurality of light sources 210 may be disposed such that a part of the light source 110 is illuminated toward the left side and the other part is illuminated toward the right side, so that the light source hole 110 of the light source 210 for accommodating the left side is incident. The 101 is a left side wall of the rectangular hole, and the adhesive layer 50 is disposed on the left side of the light source hole 110; and the light incident surface 101 of the light source hole 110 for accommodating the light source 210 of the right side is a right side wall of the rectangular hole, and the light source hole An adhesive layer 50 is disposed on the right side of 110. Thereby, the left-side light source 210 provides light to the left side wall of the light-incident surface 101 as the light-incident surface 101, and the right-side light source 210 provides light to the right side wall of the light-incident surface 101 as the light-incident surface 101, thereby The light rays provided by the plurality of light sources 210 respectively enter the light guide plate 10 on the left and right sides of the first light source hole 110, and the light enters the light guide plate 10 via the light incident surface 101, and substantially travels along the XY axis planes of the two sides.

The reflective sheet 30 is disposed under the light guide plate 10 for reflecting light leaking from the lower surface of the light guide plate 10 back to the light guide plate 10. Specifically, the reflective sheet 30 disposed under the light guide plate 10 can reflect the light energy lost from the lower surface of the light guide plate 10, so that the light energy lost from the lower surface can be returned to the light guide plate 10, and continues along the XY axis plane later. When the light shielding sheet 40 has an opening (or a light transmitting portion), it is emitted from the light emitting surface (for example, the top surface 102). The reflective sheet 30 may be a reflective film formed of a reflective material (for example, a metal foil) or a reflective sheet formed by coating a reflective material on the non-reflective film. The shape and size of the reflection sheet 30 are preferably corresponding to the light guide plate 10.

Furthermore, the reflective sheet 30 further includes a second light source hole 310, wherein the second light source hole 310 is connected to the corresponding first light source hole 110. That is, in this embodiment, the second light source holes 310 preferably have the same number, shape, and arrangement as the first light source holes 110, but have a one-to-one correspondence, but are not limited thereto. In other embodiments, the second light source hole 310 and the first light source hole 110 may have different numbers, sizes, and shapes. When the light guide plate 10 and the reflective sheet 30 are stacked, the first light source hole 110 and the second light source hole 310 are connected. The portion is adapted to accommodate the plurality of light sources 210. As shown in FIG. 3B , when the light guide plate 10 , the reflective sheet 30 and the light source 20 are combined, the light source 210 can protrude from the lower portion of the reflective sheet 30 through the second light source hole 310 into the first light source hole 110 .

The light shielding sheet 40 is disposed above the light guide plate 10 and has a light shielding pattern (for example, 40a shown in FIG. 5A) to selectively block or allow light to pass therethrough. Specifically, the light shielding sheet 40 is a light transmissive optical film and has a pattern design on the film to shield a portion of the keyboard device that does not require light. For example, the visor 40 may have a pattern corresponding to the relative position and contour of the plurality of keys on the keyboard such that the gap between adjacent keys is masked to prevent light from passing through, and the position of the corresponding plurality of keys allows light to pass through Light can be emitted from the keycap. In one embodiment, the shape and size of the light shielding sheet 40 are preferably corresponding to the light guide plate 10. Furthermore, the light shielding sheet 40 can be selectively provided The third light source hole 410, wherein the third light source hole 410 is preferably aligned with the corresponding first light source hole 110 and the second light source hole 310. The third light source hole 410 preferably has the same number, shape, and arrangement as the first light source hole 110 and/or the second light source hole 310, but has a one-to-one correspondence relationship, but is not limited thereto. In other embodiments, the third light source hole 410 and the first light source hole 110 and/or the second light source hole 310 may have different numbers, sizes, and shapes, as long as the light shielding film 40, the light guide plate 10, and the reflection sheet 30 are stacked. The portion connecting the first light source hole 110, the second light source hole 310 and the third light source hole 410 can accommodate the plurality of light sources 210 to reduce the height of the structure after stacking. In another embodiment (not shown), the light shielding film 40 may not have the third light source hole 410. When the light shielding film 40, the light guide plate 10, the reflection sheet 30, and the light source unit 20 are combined into a backlight module, the light shielding film 40 is covered. Above the light source 210.

As shown in FIG. 3B and FIG. 3C, the first adhesive layer 50 is preferably a glue layer, and can be disposed on the top surface 102 and the bottom surface 103 of the light guide plate 10 by, for example, printing or coating, to adhere the light shielding film 40 to the light shielding sheet 40, respectively. The top surface 102 of the light guide plate 10 and the adhesive reflection sheet 30 are on the bottom surface 103 of the light guide plate 10 to reduce the chance of a gap between the light guide plate 10 and the reflection sheet 30 and the light shielding sheet 40 in front of the light-emitting surface 210a. The first adhesive layer 50 is disposed in front of the light emitting surface 210a of the light source 210, and the first adhesive layer 50 and the light emitting surface 210a have a spacing d, wherein the spacing d is greater than 1 mm; thus avoiding an adhesive (such as water gel) The tolerances during coating or printing cause the adhesive layer 50 to be offset and excessively close to or superimposed on the light emitting surface 210a, resulting in the light source 210 dissipating too much light energy from the adhesive layer 50. Moreover, the spacing d between the first adhesive layer 50 and the light-emitting surface 210a is preferably determined according to the position at which the light source 210 generates a halo phenomenon in the light guide plate 10. In this embodiment, the pitch d is preferably 2 to 3 mm. .

Specifically, the light emitting surface 210a of the light source 210 extends in the X-axis direction and is parallel to the XZ-axis plane. The light-emitting surface 210a is translated along the Y-axis toward the light guide plate 10 to define a halo space 60, and the first adhesive layer 50 is compared. Preferably, at least a portion of the Z-axis projection area is located in the halo space 60 Inside. In other words, the first adhesive layer 50 is at least partially located in the range in which the halo space 60 extends in the Z-axis direction, and the distance d between the first adhesive layer 50 and the light-emitting surface 210a on the Y-axis is greater than 1 mm and preferably 2 ~3mm.

Furthermore, the X-axis and Z-axis ranges of the halo space 60 are defined by the X-axis and Z-axis dimensions of the light-emitting surface 210a, and the Y-axis range of the halo space 60 is defined by the amount of translation in front of the light-emitting surface 210a. For example, the Y-axis shift amount of this embodiment depends on the position where the light source 210 generates a halo phenomenon on the light guide plate 10, for example, 1 to 5 mm. As shown in FIG. 3C, the halo space 60 has a first X-axis boundary 60a and a second X-axis boundary 60b, the first X-axis boundary 60a is aligned with the X-axis positive direction of the positive-source light-emitting surface 210a, and the second X-axis boundary 60b The X-axis negative direction boundary of the positive light source emitting surface 210a is such that the distance between the first X-axis boundary 60a and the second X-axis boundary 60b is the light-emitting surface X-axis length L1 of the light-emitting surface 210a projected on the X-axis. The portion of the first adhesive layer 50 located in the Z-axis projection area of the halo space 60 projected on the X-axis has a first adhesive layer X-axis length L2, wherein the first adhesive layer X-axis length L2 is smaller than the light-emitting surface X-axis length L1 . In this embodiment, the first adhesive layer 50 is completely located in the Z-axis projection area of the halo space 60, and the first adhesive layer X-axis length L2 is the first X-axis end point 50a of the first adhesive layer 50 and the first The distance between the two X-axis endpoints 50b. That is, from the top view of FIG. 3C, the first adhesive layer 50 is completely within the X-axis range defined by the halo space 60, and the first adhesive layer 50 is at both ends 50a, 50b on the X-axis. The halo space 60 is inside the two boundaries 60a, 60b on the X-axis.

In addition, in this embodiment, the first X-axis boundary 60a and the first X-axis end point 50a have a first spacing d1, and the second X-axis boundary 60b and the second X-axis end point 50b have a second spacing d2, wherein the first The pitch d1 and the second pitch d2 are preferably both greater than 0.5 mm and less than 1 mm. That is, from the top view of Fig. 3C, the two end points 50a, 50b of the first adhesive layer 50 on the X-axis have a distance d1, d2 from the two boundaries 60a, 60b of the halo space 60 on the X-axis, respectively. Where the spacings d1, d2 are preferably greater than 0.5 Mm and less than 1 mm, so that the first adhesive layer 50 does not completely cover the light-emitting surface 210a, and does not affect all the light emitted directly in front, thus reducing the influence on the brightness performance. In this embodiment, the first adhesive layer has an X-axis length L2 of 1 to 2 mm and preferably 2 mm, and the first adhesive layer 50 is projected on the Y-axis with a first adhesive layer Y-axis length L3, wherein the first adhesive layer The Y-axis length L3 is 1 to 2 mm and preferably 1 mm. In other words, in this embodiment, the first adhesive layer 50 is preferably a rectangular adhesive layer of 1 mm x 2 mm, but is not limited thereto. In other embodiments, the first adhesive layer 50 may have other suitable shapes, such as an elliptical shape, a circular shape, a triangular shape, and the like, and the first adhesive layer 50 preferably does not exceed a rectangular range of 1 mm x 2 mm, but is not limited thereto.

In the embodiment of FIGS. 3A-3C, the first adhesive layer 50 is completely within the Z-axis projection area of the halo space 60 such that "the first adhesive layer 50 is located within the Z-axis projection area of the halo space 60. The length L2" projected on the X-axis is equal to the length L4" of the first adhesive layer 50 projected on the X-axis, but is not limited thereto. In other embodiments, as shown in FIG. 4A, the first adhesive layer 50 may be only partially located within the Z-axis projection area of the halo space 60 such that "the first adhesive layer 50 is located within the Z-axis projection area of the halo space 60. The first adhesive layer X-axis length L2" projected on the X-axis is smaller than the length L4" of the first adhesive layer 50 projected on the X-axis. In the embodiment shown in FIG. 4A, the first adhesive layer 50 includes a first portion 510 and a second portion 520, wherein the first portion 510 is located in the Z-axis projection area of the halo space 60, and the second portion 520 is located in the light. The Z-axis projection area of the halo space 60 is outside, and the first portion 510 and the second portion 520 are connected to each other by a common side 50c. In this embodiment, the first adhesive layer X-axis length L2 projected on the X-axis is smaller than the X-axis length L1 of the light-emitting surface, and the length L4 of the first adhesive layer 50 on the X-axis projection may be greater than or equal to the actual demand. Or less than the X-axis length L1 of the light-emitting surface. In this embodiment, the first adhesive layer X-axis length L2 is preferably about 1 to 2 mm, and a gap is still maintained between the X-axis end point 50a of the first portion 510 and the X-axis boundary 60a of the halo space 60.

Furthermore, in another embodiment, as shown in FIG. 4B, the first adhesive layer 50 may include a first adhesive portion 530 and a second adhesive portion 540, wherein each of the first adhesive portion 530 and the second adhesive portion 540 has a portion ( For example, 532, 542) is located in the Z-axis projection area of the halo space 60, and the portion 532 of the first adhesive portion 530 and the portion 542 of the second adhesive portion 540 have a gap G to avoid the first adhesion. Layer 50 completely covers the light emitting surface 210a, affecting all of the light in front of it. The portion 532 of the first adhesive portion 530 and the portion 542 of the second adhesive portion 540 have a first adhesive portion X-axis length L21 and a second adhesive portion X-axis length L22 on the X-axis projection, respectively, and the first adhesive portion X The total length of the shaft length L21 and the second adhesive portion X-axis length L22 is smaller than the X-axis length L1 of the light-emitting surface, and the sum is preferably 1 to 2 mm.

It should be noted that, in the embodiment of FIG. 4B , the first adhesive portion 530 and the second adhesive portion 540 are partially located within the Z-axis projection range of the halo space 60 , but are not limited thereto. In other embodiments, the first adhesive layer can be designed such that there is a gap G between the first adhesive portion and the second adhesive portion and is completely within the Z-axis projection range of the halo space 60, respectively.

Furthermore, in another embodiment, as shown in FIG. 5A and FIG. 5B, in addition to the first adhesive layer 50, the backlight module may further include at least one second adhesive layer 70 for respectively adhering at least one film (for example, reflection). The sheet 30 and the light shielding sheet 40) and the light guide plate 10 are used to reinforce the adhesion between the diaphragm and the light guide plate 10. The second adhesive layer 70 preferably surrounds the light source 210 and has a gap (eg, G1, G2) with at least a portion of the first adhesive layer 50. In this embodiment, the second adhesive layer 70 has three sides of a right side, a middle side and a left side, and is disposed in an adhesive layer similar to a U-shaped outline, and surrounds the side of the light source 210 other than the light emitting surface 210a ( That is, the second adhesive layer 70 is disposed adjacent to the non-emitting surface of the light source 210; that is, the right side extends to the right side of the light emitting surface 210a, and the middle side extends to the opposite side of the light emitting surface opposite to the light emitting surface 210a, and the left side extends to The left side of the light emitting surface 210a. The first adhesive layer 50 is set in the word "U" The open side of the shape has a gap G1, G2 with the right side and the left side of the U-shape, so that the first adhesive layer 50 and the second adhesive layer 70 together form a non-closed annular adhesive layer pattern. That is, the non-closed annular pattern surrounds the light source 210 and the opening of the non-closed annular pattern (ie, the gap G1, G2 of FIGS. 5A to 5B or the gap G of FIG. 6A and FIG. 6B below) corresponds to the light-emitting surface. 210a, and light can travel in the light guide plate 10 at a corresponding gap (eg, G1, G2, or G).

In another embodiment, as shown in FIG. 6A, the second adhesive layer 70 is disposed to surround the three sides of the light source 210 to form an adhesive layer similar to a U-shaped pattern. The first adhesive layer 50 is disposed on the U. The opening side of the glyph is connected to the right side of the U-shape and has a gap G to the left side, and the light is transmitted in the light guide plate 10 at the corresponding gap G. In another embodiment, as shown in FIG. 6B, the first adhesive layer 50 includes a first adhesive portion 530 and a second adhesive portion 540. The second adhesive layer 70 surrounds the light source 210 in a non-closed manner and is connected to the first side. The adhesive portion 530 and the second adhesive portion 540 have a gap G between the first adhesive portion 530 and the second adhesive portion 540. In other words, the first adhesive portion 530 and the second adhesive portion 540 have a configuration similar to that of FIG. 4B , wherein the opposite ends of the first adhesive portion 530 and the second adhesive portion 540 are respectively connected to the two sides of the “U” shape. A gap G is formed between the opposite ends of the first adhesive portion 530 and the second adhesive portion 540.

It should be noted that, in the embodiment of FIG. 5A to FIG. 6B, the backlight module of the present invention comprises a first adhesive layer 50 disposed in front of the light emitting surface 210a of the light source 210 and a second adhesive layer 70 surrounding the light source 210. The non-closed annular adhesive layer is designed such that the front side of the light-emitting surface 210a is not completely covered by the adhesive layer and has a proper gap, so that a part of the light is guided by the first adhesive layer 50 after the light of the light source 210 is conducted into the light guide plate 10. Lost, but most of the light can still continue to travel in the light guide; this will only make the overall optical brightness slightly reduced, for example, only about 10% or less, but it can effectively improve the serious halo in front of the light source 210. Phenomenon; users cannot It is noticed that the overall brightness loss of the backlit keyboard is different, but it can obviously feel the improvement of the excessive light halo problem in front of the light source.

In addition, in the above embodiment, the reflective sheet 30 and the light shielding sheet 40 are respectively disposed on both sides of the light guide plate 10. However, according to actual needs, the backlight module can selectively provide only one of the reflective sheet 30 and the light shielding sheet 40 on the light guide plate. One side. In another embodiment, when the light leakage between the key caps on the backlight module is negligible, the backlight module may omit the above-mentioned light shielding film. For example, when the metal base plate opening of the button module 2 is only opened directly under the key cap, and the metal cap of the relatively wide width is shielded at the gap of the key cap, the upper light shielding sheet can be omitted. In addition, in another embodiment, if the lost light energy under the backlight module is limited and negligible, the backlight module may omit the lower reflective sheet. For example, when the material of the notebook computer under the backlight module has a high reflectivity, the lower reflection sheet can be omitted.

Compared with the prior art, the backlight module of the present invention closely adheres the optical film and the light guide plate by an adhesive layer disposed in front of the light emitting surface of the light source, thereby reducing the chance of creating a gap between the light guide plate and the optical film, thereby improving the light. Halo phenomenon and enhance the brightness performance, and the design of the non-closed adhesive layer reduces the possibility of excessive light leakage caused by excessive adhesion of the light source.

The present invention has been described by the above embodiments, but the above embodiments are for illustrative purposes only and are not intended to be limiting. It will be apparent to those skilled in the art that the embodiments specifically described herein may have other modifications of the embodiments. Accordingly, the scope of the invention is intended to cover such modifications and are only limited by the scope of the appended claims.

101‧‧‧Into the glossy surface

210‧‧‧Light source

210a‧‧‧Lighting surface

50‧‧‧First adhesive layer

50a‧‧‧First X-axis endpoint

50b‧‧‧second X-axis endpoint

60‧‧‧Halo space

60a‧‧‧First X-axis boundary

60b‧‧‧Second X-axis boundary

L1‧‧‧Lighting surface X-axis length

L2‧‧‧First adhesive layer X-axis length

L3‧‧‧First adhesive layer Y-axis length

D‧‧‧ spacing

D1‧‧‧first spacing

D2‧‧‧second spacing

Claims (11)

A backlight module includes: a light guide plate having a top surface, a bottom surface and a light incident surface, the light guide plate extending substantially along an X axis and a Y axis, the X axis, the Y axis and a Z The axes are orthogonal to each other; a light source having a light emitting surface for providing light toward the light incident surface, the light emitting surface extending along the X axis, the light emitting surface projected on the X axis having a light emitting surface X-axis length, The light emitting surface defines a halo space along the Y axis to translate toward the light guide plate; at least one film disposed on at least one of the top surface and the bottom surface; and at least one first adhesive layer having at least a portion In the Z-axis projection area of the halo space, the first adhesive layer is used to adhere the at least one film to the light guide plate, wherein the first adhesive layer and the light emitting surface are spaced apart from each other on the Y-axis. ~3mm, and the portion of the first adhesive layer projected on the X-axis has a first adhesive layer X-axis length, and the first adhesive layer X-axis length is smaller than the X-axis length of the light-emitting surface. The backlight module of claim 1, wherein the halo space has a first X-axis boundary and a second X-axis boundary, the first adhesive layer having a first X-axis end point and a second X-axis end An end point, the first adhesive layer is completely located in the Z-axis projection area of the halo space, and the first X-axis boundary has a first spacing from the first X-axis end point, the second X-axis boundary And a second spacing from the second X-axis end point, the first spacing and the second spacing being greater than 0.5 mm and less than 1 mm. The backlight module of claim 1, wherein the first adhesive layer has an X-axis length of 2 mm, and the first adhesive layer has a first adhesive layer Y-axis length projected on the Y-axis, the first adhesive layer The length of the Y axis is 1 mm. The backlight module of claim 1, wherein the at least one film comprises a reflective sheet and a light shielding film At least one of the adhesive layers is used to adhere the reflective surface to the bottom surface and/or to adhere the light shielding sheet to the top surface. The backlight module of claim 1, further comprising an at least one second adhesive layer for adhering the at least one film and the light guide plate, wherein the light source further has a non-light emitting surface, and the Z-axis is viewed from the Z-axis. The second adhesive layer is adjacent to the non-light emitting surface of the light source, and the first adhesive layer and the second adhesive layer together form a non-closed annular pattern, the non-closed annular pattern surrounds the light source and the non-closed type The opening of the annular pattern corresponds to the light emitting surface. The backlight module of claim 5, wherein the second adhesive layer has three sides of a right side, a middle side and a left side, and the right side extends to the right side of the light emitting surface, and the middle side extends On the opposite side of the light emitting surface opposite to the light emitting surface, the left side extends to the left of the light emitting surface. The backlight module of claim 6, wherein the second adhesive layer has a U-shaped outline and a U-shaped opening, and the first adhesive layer is disposed on a side corresponding to the U-shaped opening. The backlight module of claim 6, wherein the first adhesive layer and the left side and the left side respectively have a gap, and the light can travel in the light guide plate corresponding to the gap. The backlight module of claim 1, further comprising an at least one second adhesive layer for adhering the at least one film and the light guide plate, wherein the light source further has a non-light emitting surface, and the Z-axis is viewed from the Z-axis. The first adhesive layer includes a first adhesive portion and a second adhesive portion. The second adhesive layer is adjacent to the non-light emitting surface and connects the first adhesive portion and the second adhesive portion to make the first adhesive portion and There is a gap between the second adhesive portions, and the light can travel in the light guide plate at corresponding gaps. The backlight module of claim 9, wherein the second adhesive layer has three sides of a right side, a middle side and a left side, and a right side extends to the right of the light emitting surface, and the middle side extends with The opposite side of the light emitting surface opposite to the light emitting surface extends to the left of the light emitting surface. The backlight module of claim 10, wherein the second adhesive layer has a U-shaped outline and a U-shaped opening, and the first adhesive layer is disposed on a side corresponding to the U-shaped opening.