TWI545378B - Backlight module - Google Patents

Description

Backlight module

The present invention relates to a backlight module, and more particularly to a backlight module capable of maintaining the brightness of light in a light guide plate.

At present, the backlight module is one of the key components of the display device. For example, the display device can be a liquid crystal display device. Since the liquid crystal itself does not emit light, the function of the backlight module is sufficient supply. A light source with uniform brightness and distribution enables the display device to display images properly.

The assembly process of the conventional backlight module is mostly after the light-incident surface of the light guide plate is close to the light-emitting surface of the light-emitting unit, and then the double-sided adhesive is used to fix the light guide plate to the top surface of the circuit board carrying the light-emitting unit, but The surface adhesive is disposed on the top surface of the circuit board, so that when the light guide plate is close to the light-emitting unit and the light-incident surface of the light guide plate has not been pressed against the light-emitting surface of the light-emitting unit, it is easy to be mistakenly adhered to the double-sided tape, so that the light guide plate and the light-emitting plate There is an excessive gap between the cells, which affects the overall brightness of the light entering the light guide plate.

In addition, because of the thickness of the double-sided tape itself, when it is bonded between the light guide plate and the circuit board, the height of the light guide plate is raised to cause the light-incident surface of the light guide plate and the light-emitting surface of the light-emitting unit to be completely coupled due to misalignment. The light emitted by the light emitting unit is partially irradiated to the double-sided tape to reduce the overall brightness entering the light guide plate. Further, after the light enters the light guide plate, under the light guide plate The double-sided tape of the square is also thermally expanded by the heat generated by the circuit board and the light guide plate to increase the thickness thereof, so that the overall luminance after the light emitted from the light-emitting unit enters the light guide plate is further affected and reduced. On the other hand, the material of the double-sided tape adhered to the lower side of the light guide plate also affects the overall brightness of the light emitted from the light-emitting unit after entering the light guide plate.

The "Prior Art" section is only intended to aid in understanding the present invention, and thus the disclosure of the prior art paragraphs may contain some conventional techniques that are not known to those of ordinary skill in the art. The matters disclosed in the "Prior Art" section, which do not represent the subject matter or the problems to be solved by one or more embodiments of the present invention, are known or recognized by those of ordinary skill in the art prior to the present application.

One of the objects of the present invention is to provide a backlight module for improving the problems caused by the prior art.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein.

In order to achieve one or a part or all of the above or other purposes, the present invention provides a backlight module including a circuit board, a light emitting unit, and a light guide plate. The circuit board has opposing first and second sides. The light emitting unit is disposed on the first surface of the circuit board, and the light emitting unit has a first light emitting surface for emitting light. The light guide plate includes a second light emitting surface, a bottom surface, and a light incident surface. The bottom surface is disposed opposite to the second light exit surface. The light entrance surface is connected to the second light emitting surface and the bottom surface. The light incident surface has a concave portion, and the concave portion is recessed in the light incident surface, and the concave portion and the second light emitting surface and the bottom surface respectively have a spacing, wherein one end portion of the circuit board is embedded in the concave portion, and the first light emitting surface of the light emitting unit Abuts on the entrance surface.

In an embodiment of the invention, the recess has an opposite first inner surface and a second inner surface, and the second inner surface is located between the first inner surface and the bottom surface, and the second surface of the circuit board is located on the first surface Between the second inner surfaces of the recesses.

In an embodiment of the invention, the backlight module further includes a glue disposed between the second surface of the circuit board and the second inner surface of the recess.

In an embodiment of the invention, the backlight module further includes a fixing member for fixing one end of the circuit board in the recess.

In an embodiment of the invention, the light incident surface of the light guide plate completely covers the first light emitting surface of the light emitting unit.

In an embodiment of the invention, the recess forms a cavity with the circuit board.

In an embodiment of the invention, the backlight module further includes a frame body for accommodating the light-emitting unit, the circuit board and the light guide plate, wherein the frame body has a carrying portion, and the carrying portion carries the circuit board.

In an embodiment of the invention, the bearing portion abuts on the light incident surface of the light guide plate.

In an embodiment of the invention, the recess has a third inner surface, the third inner surface connecting the first inner surface and the second inner surface, respectively, and the third inner surface forms an obtuse angle with the second inner surface.

In an embodiment of the invention, the light guide plate forms a visible area and an invisible area, and the recessed portion is located in the invisible area.

In an embodiment of the invention, the second illuminating surface is located in the invisible area and has a combination of reflective structures.

The circuit board of the backlight module of the embodiment of the present invention can be embedded in the recessed portion of the light guide plate, so that the first surface of the circuit board on which the light emitting unit is disposed is straight. The grounding contact is connected to the bottom surface of the light guide plate, and the light incident surface of the light guide plate can abut the light incident surface of the light emitting unit, and then the light guide plate and the circuit board are further fixed to complete the assembly of the backlight module. Therefore, there is no medium that affects the brightness of the light between the bottom surface of the light guide plate and the first surface of the circuit board, and the overall brightness of the light emitted by the light-emitting unit into the light guide plate can be maintained. On the other hand, after the circuit board is embedded in the recessed portion of the light guide plate, the light-incident surface of the light guide plate needs to be abutted on the first light-emitting surface of the light-emitting unit, and the circuit board and the light guide plate are fixed to complete the assembly of the backlight module. Therefore, the backlight module of the embodiment of the invention has the problem of avoiding the gap between the light-emitting unit and the light guide plate when the circuit board and the light guide plate are fixed, and has the advantages of simple assembly.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

100, 200, 300‧‧‧ backlight module

110‧‧‧Circuit board

112‧‧‧ first side

114‧‧‧ second side

116‧‧‧End

120‧‧‧Lighting unit

122‧‧‧The first glazing

122a‧‧‧ top side

130‧‧‧Light guide plate

130a‧‧ visible area

130b‧‧‧Invisible area

131‧‧‧ corner

132‧‧‧Second glazing

132a‧‧‧Reflective structure combination

134‧‧‧ bottom

136‧‧‧Into the glossy surface

136a‧‧‧ top side

138‧‧‧Depression

138a‧‧‧First inner surface

138b‧‧‧Second inner surface

138c‧‧‧ third inner surface

139‧‧‧ cavity

140‧‧‧colloid

150‧‧‧Fixed parts

160‧‧‧ frame

162‧‧‧Loading Department

162a‧‧‧ top

162b‧‧‧ side

170‧‧‧reflector

D1‧‧‧first spacing

D2‧‧‧second spacing

Θ‧‧‧oblate angle

FIG. 1 is a top plan view of a backlight module according to an embodiment of the invention.

2 is a cross-sectional view of the backlight module of FIG. 1 taken along section line A-A'.

3 is a top plan view of a backlight module in accordance with another embodiment of the present invention.

4 is a top plan view of a backlight module in accordance with still another embodiment of the present invention.

Figure 5 is a cross-sectional view of the backlight module of Figure 4 taken along section line B-B'.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

1 and FIG. 2, FIG. 1 is a top view of a backlight module according to an embodiment of the invention, and FIG. 2 is a cross-sectional view of the backlight module according to FIG. 1 along a section line A-A'. As shown in FIG. 1 and FIG. 2 , the backlight module 100 of the present embodiment includes a circuit board 110 , a light emitting unit 120 , and a light guide plate 130 . It should be understood that the light-emitting unit 120 of the present embodiment is plural, but not limited thereto. In some embodiments, the light-emitting unit 120 can be implemented by only one.

The circuit board 110 has opposite first and second faces 112 and 114 , and the light emitting unit 120 is disposed on the first surface 112 of the circuit board 110 . The light emitting unit 120 has a first light emitting surface 122 for emitting light. It should be understood that the first light-emitting surface 122 of the light-emitting unit 120 is a surface on which the light-emitting unit 120 is exposed on the circuit board 110 and emits light. In this embodiment, the circuit board 110 can be a flexible printed circuit board, and the light emitting unit 120 can be a light emitting diode, but is not limited thereto.

On the other hand, the light guide plate 130 includes a second light-emitting surface 132, a bottom surface 134, and a light-incident surface 136. The bottom surface 134 is disposed opposite to the second light-emitting surface 132, and the light-incident surface 136 is connected to the second light-emitting surface 132 and the bottom surface 134. In this embodiment, the light incident surface 136 has a recessed portion 138, and the recessed portion 138 is recessed in the light incident surface 136, and the recessed portion 138 and the second light exiting surface 132 and the bottom surface 134 respectively have a spacing. In detail, the recess 138 has an opposite first inner surface Face 138a and second inner surface 138b, and second inner surface 138b is located between first inner surface 138a and bottom surface 134. Therefore, the distance between the first inner surface 138a of the recessed portion 138 and the second light-emitting surface 132 of the light guide plate 130 may be defined as a first pitch d1, a distance between the second inner surface 138b of the recessed portion 138 and the bottom surface 134 of the light guide plate 130. The length of the first spacing d1 is greater than the length of the second spacing d2, but is not limited thereto. In addition, the recess 138 of the embodiment may further have a third inner surface 138c, and the third inner surface 138c connects the first inner surface 138a and the second inner surface 138b, respectively, wherein the third inner surface 138c and the second inner surface 138b The obtuse angle θ is formed, and the obtuse angle θ faces the light incident surface 136 of the light guide plate 130, but is not limited thereto. In the present embodiment, the light guide plate 130 has a Y-shaped cross section, that is, the light guide plate 130 of the present embodiment forms a Y-shaped cross section due to the arrangement of the recessed portions 138, but is not limited thereto.

In the present embodiment, the light guide plate 130 may define a visible area 130a and an invisible area 130b, wherein the recessed portion 138 is located in the invisible area 130b. When the visible area 130a and the invisible area 130b are formed into a module or a device, they are defined according to whether or not the light guide plate 130 is shielded from being exposed to the outside. In addition, the portion of the second light-emitting surface 132 located in the invisible area 130b has a reflective structure combination 132a, and the reflective structure combination 132a can reflect the light that is incident on the second light-emitting surface 132 of the invisible area 130b into the light-guide plate 130, to further reflect The light is guided from the second light-emitting surface 132 of the visible area 130a, but is not limited thereto. For example, the reflective structure combination 132a may be a plurality of reflective structures formed on the second light-emitting surface 132. Further, the reflective structure combination 132a may be a reflective layer formed on the second light-emitting surface 132, but limit. On the other hand, since the light guide plate 130 has the recessed portion 138 in the invisible area 130b, since the recessed portion 138 cannot conduct light, only the light guide plate 130 can be used to conduct light at other portions of the invisible area 130b, and the light guide plate 130 is in the invisible area. The thickness of 130b must be substantially greater than the thickness of the light guide plate 130 in the visible region 130a. It should be understood that the aforementioned thickness may be the shortest linear distance between the second light exit surface 132 and the bottom surface 134. Further, the thickness of the light guide plate 130 in the invisible area 130b may gradually decrease toward the light incident surface 136, but is not limited thereto.

In addition, the one end portion 116 of the circuit board 110 is embedded in the recessed portion 138 of the light guide plate 130, and the first light emitting surface 122 of the light emitting unit 120 abuts the light incident surface 136 of the light guide plate 130, and at the same time, the second portion of the circuit board 110 The face 114 is located between the first face 112 and the second inner surface 138b of the recess 138. When the one end portion 116 of the circuit board 110 is embedded in the recess portion 138 of the light guide plate 130, the first surface 112 of the circuit board 110 can directly fit on the first inner surface 138a of the recess portion 138, so that the first surface of the circuit board 110 There is no additional medium between the surface 112 and the light guide plate 130. That is, there is no brightness between the first surface 112 of the circuit board 110 and the light guide plate 130 that affects the light entering the light guide plate 130. Medium, such as double-sided tape, adhesive, etc.

In this embodiment, the light incident surface 136 of the light guide plate 130 completely covers the first light emitting surface 122 of the light emitting unit 120, and at the same time, since the first surface 112 of the circuit board 110 can directly adhere to the first portion of the recessed portion 138 The inner surface 138a is such that there is no gap existing between the first surface 112 of the circuit board 110 and the light guide plate 130. Therefore, the light incident surface 136 of the light guide plate 130 and the first light exit surface 122 of the light emitting unit 120 It can be fully coupled, so that the light emitted from the first light-emitting surface 122 can completely enter the light-incident surface 136 of the light guide plate 130.

In this embodiment, the top edge 122a of the first light-emitting surface 122 is cut into the top edge 136a of the light-incident surface 136, but is not limited thereto. In other embodiments, the top edge of the light incident surface may be higher than the top edge of the first light exit surface. It should be understood that the top edge 136a of the light incident surface 136 and the top edge 122a of the first light exit surface 122 are The smooth surface 136 and the first light exit surface 122 are away from one side of the circuit board 110.

In this embodiment, the backlight module 100 further includes a colloid 140 disposed between the second surface 114 of the circuit board 110 and the second inner surface 138b of the recess 138. The colloid 140 can be bonded to the second surface 114 of the circuit board 110. The circuit board 110 and the light guide plate 130 are bonded to each other and the second inner surface 138b of the recessed portion 138. In this embodiment, the adhesive 140 can be an adhesive such as a double-sided tape or glue, but is not limited thereto. In addition, in other embodiments, the recessed portion 138 and the circuit board 110 form a cavity 139. When the colloid 140 is a liquid adhesive, the cavity 139 can accommodate the overflow of the circuit board 110 and the light guide plate 130 when they are bonded to each other. Colloid 140, but not limited to this.

In addition, the circuit board 110 and the light guide plate 130 are not limited to be fixed only by the bonding of the colloid 140. In some embodiments, referring to FIG. 3, a top view of a backlight module in accordance with another embodiment of the present invention is illustrated. As shown in FIG. 3, the backlight module 200 of the present embodiment may include a fixing member 150, and the colloid 140 of the backlight module 100 of the foregoing embodiment may not be disposed. The fixing member 150 may fix one end portion 116 of the circuit board 110 to the recess. In section 138. For example, the fixing member 150 can be a screw. After the one end portion 116 of the circuit board 110 is embedded in the recess portion 138 of the light guide plate 130, the fixing member 150 can lock the one end portion 116 of the circuit board 110 to the light guide plate 130. The recessed portion 138 is locked by a buckle or the like, but is not limited thereto. Further, the number of the fixing members 150 of the present embodiment is two, and is disposed at a position adjacent to the opposite two corners 131 of the light incident surface 136 of the light guide plate 130, but is not limited thereto. In other embodiments, the number of fasteners 150 can be only one.

Please refer to FIG. 4 and FIG. 5. FIG. 4 is a top view of a backlight module according to still another embodiment of the present invention. Figure 5 is a cross-sectional view of the backlight module of Figure 4 taken along section line B-B'. As shown in Figure 4 and Figure 5, it should be understood that The backlight module 300 of the embodiment is substantially the same as the backlight module 100 of the embodiment shown in FIG. 1 and FIG. 2 . The main difference is that the backlight module 300 of the embodiment further includes a frame 160 , and the frame 160 can be The light emitting unit 120, the circuit board 110 and the light guide plate 130 are accommodated, wherein the frame body 160 has a carrying portion 162, wherein the top surface 162a of the carrying portion 162 can carry the second surface 114 of the circuit board 110, and a side surface 162b of the carrying portion 162 The light incident surface 136 of the light guide plate 130 can be abutted. In detail, the side surface 162b of the carrying portion 160 can abut the light incident surface 136 between the recessed portion 138 and the bottom surface 134 of the light guide plate 130, thereby increasing the stability of the backlight module 300 after the assembly of the entire backlight module 300 and increasing the backlight. The convenience of assembling the module 300 is not limited thereto. In this embodiment, the carrying portion 162 can be disposed inside the accommodating space formed by the frame 160, but is not limited thereto. In this embodiment, the backlight module 300 further includes a reflective sheet 170, wherein the reflective sheet 170 is disposed between the light guide plate 130 and the frame 160. In one embodiment, the reflective sheet 170 can be disposed only between the bottom surface 134 of the light guide plate 130 and the frame 160. In another embodiment, the reflective sheet 170 is disposed between the bottom surface 134 of the light guide plate 130 and the frame 160, and further extends toward the light emitting unit 120 to serve as a reflector of the light emitting unit 120.

The circuit board of the backlight module of the embodiment of the present invention can be embedded in the recessed portion of the light guide plate, so that the first surface of the circuit board on which the light emitting unit is disposed directly contacts the bottom surface of the light guide plate and the light incident surface of the light guide plate can be abutted It is connected to the light incident surface of the light emitting unit. Therefore, there is no medium affecting the light intensity between the bottom surface of the light guide plate and the first surface of the circuit board, and the light emitted by the light emitting unit can be kept into the overall brightness of the light guide plate. On the other hand, after the circuit board carrying the light-emitting unit is embedded in the recessed portion of the light guide plate, the light-incident surface of the light guide plate needs to be abutted on the first light-emitting surface of the light-emitting unit and the circuit board is fixed on the recessed portion of the light guide plate. The assembly of the backlight module can be completed. Therefore, the backlight module of the embodiment of the present invention further The problem of avoiding the gap between the light-emitting unit and the light guide plate when the circuit board and the light guide plate are fixed is also provided, and the assembly is simple.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention. In addition, the terms "first", "second" and the like mentioned in the specification or the scope of the claims are only used to name the elements or distinguish different embodiments or ranges, and are not intended to limit the number of elements. Upper or lower limit.

100‧‧‧Backlight module

110‧‧‧Circuit board

112‧‧‧ first side

114‧‧‧ second side

116‧‧‧End

120‧‧‧Lighting unit

122‧‧‧The first glazing

122a‧‧‧ top side

130‧‧‧Light guide plate

130a‧‧ visible area

130b‧‧‧Invisible area

132‧‧‧Second glazing

132a‧‧‧Reflective structure combination

134‧‧‧ bottom

136‧‧‧Into the glossy surface

136a‧‧‧ top side

138‧‧‧Depression

138a‧‧‧First inner surface

138b‧‧‧Second inner surface

138c‧‧‧ third inner surface

139‧‧‧ cavity

140‧‧‧colloid

D1‧‧‧first spacing

D2‧‧‧second spacing

Θ‧‧‧oblate angle

Claims (11)

A backlight module includes: a circuit board having an opposite first surface and a second surface; at least one light emitting unit disposed on the first surface of the circuit board, the light emitting unit having a first light emitting surface, And a light guide plate, comprising: a second light emitting surface; a bottom surface disposed opposite to the second light emitting surface; and a light incident surface connecting the second light emitting surface and the bottom surface, the light incident surface Having a recessed portion, and the recessed portion is recessed in the light incident surface, the recessed portion and the second light exiting surface and the bottom surface respectively have a spacing; wherein one end portion of the circuit board is embedded in the recessed portion, and the The first light-emitting surface of the light-emitting unit abuts on the light-incident surface. The backlight module of claim 1, wherein the recess has a first inner surface and a second inner surface, and the second inner surface is located between the first inner surface and the bottom surface The second face of the circuit board is between the first face and the second inner surface of the recess. The backlight module of claim 2, further comprising a colloid disposed between the second surface of the circuit board and the second inner surface of the recess. The backlight module of claim 1, further comprising at least one fixing member, the end portion of the circuit board being fixed in the recess. The backlight module of claim 1, wherein the light guide The light incident surface of the panel completely covers the first light exiting surface of the light emitting unit. The backlight module of claim 1, wherein the recess forms a cavity with the circuit board. The backlight module of claim 1, further comprising a frame for accommodating the light emitting unit, the circuit board and the light guide plate, wherein the frame body has a carrying portion, and the carrying portion carries the Circuit board. The backlight module of claim 7, wherein the bearing portion abuts the light incident surface of the light guide plate. The backlight module of claim 2, wherein the recess has a third inner surface, the third inner surface connecting the first inner surface and the second inner surface, respectively, the third inner surface and The second inner surface forms an obtuse angle. The backlight module of claim 1, wherein the light guide plate forms a visible area and an invisible area, and the recessed portion is located in the invisible area. The backlight module of claim 10, wherein the second light exiting surface has a reflective structure combination in the invisible area.