TWI829395B - Backlight module and display device comprising the same - Google Patents

Abstract

A backlight module is described, which includes a carrier, a light guide element, a light-emitting unit, and an adhesive unit. The carrier has an accommodating space. The light guide element is accommodated in the accommodating space and has a light-incident side. The light emitting unit is arranged close to the light-incident side. The adhesive unit is disposed between the light guide element and the carrier, and includes a first adhesive layer, a second adhesive layer and a reflection structure. The first adhesive layer is attached to the light guide element. At least a part of the reflective structure is disposed between the first adhesive layer and the second adhesive layer. The transmittance of the first adhesive layer is lower than that of the second adhesive layer.

Description

Backlight module and display device including backlight module

The present invention relates to a backlight module and a display device including the backlight module, and in particular, to a backlight module applicable to a display device.

Generally, LCD monitors mainly include backlight modules and LCD panels. The backlight module is provided with a light guide plate that uniformly guides the light from the light-emitting unit to all parts of the liquid crystal display panel. There is a light guide plate fixing glue on the bottom of the light guide plate. The fixing glue of the light guide plate is a transparent colloid, and is combined with the reflective sheet to form a composite structure. The main function of the light guide plate fixing glue is to fix the light guide plate close to the light source. When the ambient temperature changes, the light guide plate fixing glue can ensure the alignment height of the light guide plate and the light source, or ensure that the light guide plate and the light source maintain a fixed distance in the plane direction to maintain light utilization efficiency and can also adapt to the module. Designs tend to have narrow bezels.

Since the light guide plate fixing glue itself is transparent or translucent, part of the light from the light-emitting unit is easily exported through the light guide plate fixing glue body and at its end. On the one hand, the LCD panel is close to the frame, causing bright bands and hot spots ( hotspot), which in turn affects the visual beauty of the LCD panel screen. On the other hand, due to the existence of bright bands and hot spots, a wider frame must be used to cover the aforementioned bright bands or hot spots, making it difficult to design a narrow frame for an LCD panel.

Therefore, one object of the present invention is to provide a backlight module that can suppress the occurrence of bright bands and/or hot spots, and a display device including the backlight module.

According to the above object of the present invention, a backlight module is proposed. The backlight module includes a carrier, a light guide element, a light emitting unit, and a gel unit. The bearing member has an accommodation space. The light guide element is accommodated in the accommodation space and has a light incident surface. The light-emitting unit is arranged on a side close to the light incident surface. The colloid unit is disposed between the light guide element and the carrier, and includes a first glue layer, a second glue layer and a reflective structure. The first adhesive layer is attached to the light guide element. At least a portion of the reflective structure is disposed between the first glue layer and the second glue layer. The penetration rate of the first glue layer is smaller than the penetration rate of the second glue layer.

According to an embodiment of the present invention, the second adhesive layer is attached to the bearing member.

According to another embodiment of the present invention, the light guide element has a reflective surface connected to the light incident surface. The backlight module also includes a main reflector. The main reflective sheet and the colloid unit are arranged between the reflective surface and the carrier, and the colloidal unit is closer to the light-emitting unit than the main reflective sheet.

According to another embodiment of the present invention, the reflective structure is a part of the main reflective sheet extending toward the light-emitting unit.

According to yet another embodiment of the present invention, the light-emitting unit further includes a plurality of light-emitting elements and a circuit board. The light-emitting element is arranged on the circuit board. A part of the circuit board extends between the carrier and the light guide plate, and the second adhesive layer is attached to the circuit board.

According to yet another embodiment of the present invention, the penetration rate of the first adhesive layer is no less than 40% and no more than 85%.

According to yet another embodiment of the present invention, the thickness of the first glue layer is greater than the thickness of the second glue layer.

According to another embodiment of the present invention, the first glue layer includes a color material.

According to the above object of the present invention, a display device is provided. This display device contains as before The backlight module and display panel. The display panel is arranged above the backlight module.

According to an embodiment of the present invention, the backlight module further includes a front frame. The front frame is disposed between the light guide element and the display panel to carry the display panel.

From the above, it can be seen that the present invention eliminates the light-guiding function of the first adhesive layer by reducing the transmittance of the first adhesive layer. In this way, the conventional problems of bright bands and/or hot spots in the display panel can be improved, thereby making the display device have better optical quality, and also achieving the purpose of narrowing the frame of the display device.

The present invention can also choose to add coloring matter into the first glue layer to adjust the composition of the first glue layer, so as to achieve the purpose of making the penetration rate of the first glue layer smaller than the penetration rate of the second glue layer.

On the other hand, the present invention can also adjust the thickness of the first glue layer to be greater than the thickness of the second glue layer, thereby enhancing the adhesion of the first glue layer.

10:Display device

100:Backlight module

110: Bearing part

111:Part One

111A:Top surface

112:Part 2

113: Accommodation space

114: Air gap

120:Light guide element

121: Light incident surface

122: Shiny surface

123: Reflective surface

130:Light-emitting unit

131:Light

132:Light-emitting component

133:Circuit board

140:Front frame

150: Colloidal unit

151: First glue layer

151A:Light incident surface

152:Second glue layer

153: Reflective structure

160: Main reflector

200:Display panel

201: Highlights and Hotspots

210: Shiny surface

For a more complete understanding of the embodiments and their advantages, reference is now made to the following description in conjunction with the accompanying drawings, in which: [FIG. 1A] is a schematic top view of a backlight module according to the first embodiment of the present invention. [Fig. 1B] is a schematic partial cross-sectional view cut along the AA' section line of [Fig. 1A]; [Fig. 2] is a diagram showing the penetration of the first adhesive layer according to the first embodiment of the present invention. A line graph obtained by transmittance versus hot spot degree; [Fig. 3] is a schematic partial cross-sectional view of a modified embodiment according to the first embodiment of the present invention; [Fig. 4] is a schematic diagram of a modified embodiment according to the first embodiment of the present invention. A schematic partial cross-sectional view of another modified embodiment of the present invention; [Fig. 5] illustrates a partial cross-sectional view along the AA' section line of [Fig. 1A] according to the second embodiment of the present invention. Schematic diagram of cross section.

Please refer to FIGS. 1A and 1B simultaneously. FIG. 1A is a schematic top view of a backlight module according to the first embodiment of the present invention. Figure 1B is a schematic partial cross-sectional view taken along the A-A' section line of Figure 1A. The Z direction in FIG. 1B is the normal direction of the light exit surface 210 of the display panel 200 , or can also be regarded as the stacking direction of the light guide element 120 on the colloid unit 150 . The X direction and the Y direction in FIG. 1A are respectively parallel to the light exit surface 122 of the light guide element 120, and the X direction is perpendicular to the Y direction. The X direction and the Y direction are respectively perpendicular to the Z direction shown in Figure 1B. The backlight module 100 according to an embodiment of the present invention includes a carrier 110, a light guide element 120, a light emitting unit 130, and a colloid unit 150. The bearing member 110 has an accommodation space 113 . The light guide element 120 is accommodated in the accommodation space 113 and has a light incident surface 121 . The light-emitting unit 130 is disposed on a side close to the light incident surface 121 . The glue unit 150 is disposed between the light guide element 120 and the carrier 110 and includes a first glue layer 151 , a second glue layer 152 and a reflective structure 153 . The first adhesive layer 151 is attached to the light guide element 120 . At least a part of the reflective structure 153 is disposed between the first glue layer 151 and the second glue layer 152 . The penetration rate of the first glue layer 151 is smaller than the penetration rate of the second glue layer 152 . By using the transmittance of the first glue layer 151 to be less than the transmittance of the second glue layer 152, the present invention can eliminate the light-guiding function of the first glue layer 151, thereby not only achieving the design purpose of narrow bezels, but also taking into account the overall Optical quality of the light-emitting surface, such as reducing bright bands, hotspots or unevenness on the light-emitting surface.

The display device 10 of this embodiment includes a backlight module 100 and a display panel 200 . The display panel 200 is disposed above the backlight module 100 and can be mainly combined with the backlight module 100 to provide a backlight source for the display panel 200 of the display device 10 . As shown in FIG. 1B , as shown in FIGS. 1A and 1B , the backlight module 100 mainly includes a carrier 110 , a light guide element 120 , one or more light emitting units 130 , a front frame 140 , and a gel unit 150 . The light guide element 120 can be combined with the carrier 110 through the colloid unit 150 . In this embodiment, the carrier 110 has an accommodating space 113, so that the accommodating space 113 of the carrier 110 can accommodate the light guide elements in sequence. 120, light-emitting unit 130, and colloid unit 150.

The carrier 110 includes a first part 111 and a second part 112 . In one embodiment, the plurality of first parts 111 substantially vertically surrounds the second part 112 to define the accommodation space 113 . For example, in one example, the number of the first parts 111 is four, and they are respectively arranged on each side of the second part 112 . In an exemplary example, the first part 111 and the second part 112 of the carrier 110 may together form a rectangular open box for illustrative purposes and are not intended to limit the present invention.

The light guide element 120 is disposed between the second part 112 of the carrier 110 and the front frame 140 and is accommodated in the accommodating space 113 . The light guide element 120 has a light incident surface 121 adjacent to the light emitting unit 130 and a light exit surface 122 adjacent to the display panel 200 . The light 131 from the light-emitting unit 130 enters the light guide element 120 from the light incident surface 121, and after being reflected multiple times in the light guide element 120, leaves the light guide element 120 from the light exit surface 122 and then enters the display panel 200. The light guide element 120 may be a light guide plate (LGP) or a light guide film (LGF) used in the backlight module 100 . In an exemplary example, the shape of the light guide element 120 may roughly correspond to the shape of the accommodating space 113 and be accommodated in the accommodating space 113 .

Each light-emitting unit 130 is disposed on a side close to the light incident surface 121 of the light guide element 120 , between the first part 111 of the carrier 110 and the light guide element 120 , and is accommodated in the accommodating space 113 . The light-emitting unit 130 further includes a plurality of light-emitting elements 132 and a circuit board 133. For example, the light-emitting element 132 is disposed on the circuit board 133 and the light-emitting element 132 is electrically connected to the circuit board 133. In one example, the light-emitting unit 130 and the light incident surface 121 of the light guide element 120 can be separated by an appropriate distance to form an air gap 114, so that the light 131 from the light-emitting unit 130 can first pass through the air gap 114, and then It enters the light guide element 120 from the light incident surface 121 . In an exemplary example, the light emitting unit 130 may be connected to the first part 111 of the carrier 110 or to the front frame 140, but is not limited thereto. In some examples, the light-emitting unit 130 may be an organic light-emitting diode, an inorganic light-emitting diode, or a combination thereof. Thereby, the light emitting unit 130 can provide the display panel 200 with monochromatic light or white light 131 . It should be noted that the type of the light emitting unit 130 in this embodiment is not intended to limit the present invention. In other embodiments, the light-emitting unit 130 may also utilize other different light-emitting devices. Made of light materials.

The front frame 140 is disposed between the light guide element 120 and the display panel 200 to carry the display panel 200 . The front frame 140 is disposed above the light guide element 120 and covers the light emitting unit 130 and the air gap 114, thereby preventing the light 131 from the light emitting unit 130 from directly entering the display panel 200 through the air gap 114 before entering the light guide element 120. . The front frame 140 also covers part of the light guide element 120 . The front frame 140 horizontally connects the top surface 111A of the first part 111 of the carrier 110 in the opposite direction extending along the light guide element 120 on the XY plane, so that the front frame 140 and the first part 111 of the carrier 110 cover the light emitting unit 130 . In one example, the front frame 140 may connect a side of the light-emitting unit 130 parallel to the direction in which the light guide element 120 extends.

The colloid unit 150 is disposed between the light guide element 120 and the carrier 110. In one embodiment, the colloid unit 150 is used to connect to the second part 112 of the carrier 110 and the light guide element 120 respectively. Thereby, the purpose of fixing the light guide element 120 to the second part 112 of the carrier 110 via the gel unit 150 can be achieved. Therefore, the colloid unit 150 can also be regarded as being sandwiched between the light guide element 120 and the second part 112 of the carrier 110 . In one embodiment, the colloid unit 150 includes a laminate structure composed of multiple material layers. For example, the glue unit 150 at least includes a first glue layer 151, a second glue layer 152, and a reflective structure 153. The first adhesive layer 151 or the second adhesive layer 152 may be an adhesive used for pasting reflective sheets or printed circuit boards (PCB) respectively, such as optically clear adhesive (Optically Clear Adhesive, OCA). The first glue layer 151 is attached to the light guide element 120 so that the first glue layer 151 is sandwiched between the light guide element 120 and the reflective structure 153 . In this embodiment, the second glue layer 152 is attached to the second part 112 of the carrier 110 to facilitate the glue unit 150 to fix the light guide element 120 on the carrier 110 so that the second glue layer 152 is sandwiched between the reflective structure and the light guide element 120 . 153 and the second part 112 of the carrier 110, the light guide element 120 is fixed on the carrier 110 through the second glue layer 152, thereby achieving the effect of fixing the light guide element 120. In one embodiment, at least a part of the reflective structure 153 is disposed between the first glue layer 151 and the second glue layer 152 for reflecting light. In this embodiment, the reflective structure 153 is a light-reflective material sandwiched entirely between the first glue layer 151 and the second glue layer 152 to form the glue layer. The stacked structure of the body unit 150. In one embodiment, the colloid unit 150 is disposed adjacent to the light-emitting unit 130 and between the light guide element 120 and the carrier 110 . In this way, the light entering the light guide element 120 is reflected by the reflective structure 153, and the brightness of the light exit surface adjacent to the light incident surface can be maintained.

In one embodiment, the penetration rate of the first glue layer 151 is smaller than the penetration rate 152 of the second glue layer. In this way, the amount of light 131 from the light-emitting unit 130 that passes through the first glue layer 151 near the light incident surface 151A of the light-emitting unit 130 and enters the first glue layer 151 can be reduced, thereby reducing the risk of the light guide element 120 close to the front frame 140 The purpose of producing bright bands and hot spots at locations.

第一膠層151的穿透率

85%。當第一膠層151的穿透率低於40%，則會降低第一膠層151的黏著力，而不利於第一膠層151固定導光元件120的能力，當第一膠層151的穿透率高於85%時，則容易發生亮帶及熱點出光不均勻的問題。 In one illustrative example, 40%

Penetration rate of the first adhesive layer 151

85%. When the transmittance of the first adhesive layer 151 is lower than 40%, the adhesion of the first adhesive layer 151 will be reduced, which is detrimental to the ability of the first adhesive layer 151 to fix the light guide element 120. When the first adhesive layer 151 When the transmittance is higher than 85%, the problem of uneven light emission in bright bands and hot spots is likely to occur.

FIG. 2 is a line graph illustrating the transmittance of the first adhesive layer 151 versus the degree of hot spots according to the first embodiment of the present invention. The horizontal axis in the figure is the penetration rate percentage (%), and the vertical axis is the hot spot degree evaluation value. It can be seen from the figure that when the transmittance of the first adhesive layer 151 is greater than 85%, the hot spot degree evaluation value will exceed a predetermined value, making the display panel 200 prone to the conventional bright band and hot spot 201 problems.

In some examples, when the first glue layer 151 is an optical glue containing colorants, the colorants are colorants used for low light transmittance. In some examples, the colorant is white. In this way, any one of the aforementioned methods can achieve the purpose of reducing the penetration rate of the first adhesive layer 151 to a range of no more than 85% and no less than 40%. It should be noted that the material and color of the first adhesive layer 151 in this embodiment are not intended to limit the present invention. In other embodiments, the optical glue of the first glue layer 151 can also be mixed using diffusion particles to obtain a first glue layer with lower transmittance.

In one embodiment, the thickness of the first glue layer 151 is greater than the thickness of the second glue layer 152, and can reach To increase the adhesion strength between the first adhesive layer 151 and the light guide element 120 . In other words, since the amount of coloring materials or particles added to the first glue layer 151 is greater than the amount of coloring materials or particles added to the second glue layer 152, the thickness of the first glue layer 151 must be increased to increase the amount of coloring materials or particles. The adhesive strength between the first adhesive layer 151 and the light guide element 120 is ensured.

Please refer to FIG. 3 , which is a schematic partial cross-sectional view of a modified example of the first embodiment of the present invention. In a modified embodiment, the backlight module 100 further includes a main reflective sheet 160 . The main reflection sheet 160 is accommodated in the accommodation space 113 and extends along the direction in which the light guide element 120 extends. In this modified embodiment, the main reflective sheet 160 is different from the reflective structure 153, that is to say, the main reflective sheet 160 and the reflective structure 153 are not connected to each other, so that the main reflective sheet 160 and the reflective structure 153 do not need to be installed at one time, and have the ability to assemble the backlight module. Group 100's of convenience. In this modified embodiment, the light guide element 120 has a reflective surface 123 connected to the light input surface 121, so that the first adhesive layer 151 is attached to the reflective surface 123 of part of the light guide element 120. After the light 131 from the light-emitting unit 130 enters the light guide element 120 from the light incident surface 121, it passes through the cooperation of the reflective structure 153 and the main reflective sheet 160, and is reflected uniformly by the reflective surface 123 in the light guide element 120 multiple times. is transmitted to all parts of the light guide element 120. In this modified embodiment, the main reflective sheet 160 and the colloid unit 150 are independently disposed between the reflective surface 123 and the carrier 110 . In particular, the colloid unit 150 is closer to the light-emitting unit 130 than the main reflective sheet 160 . The reflective structure 153 is generally disposed between the first glue layer 151 and the second glue layer 152, so that the first glue layer 151, the second glue layer 152, and the reflective structure 153 generally correspond to the shapes and sizes of each other. In addition, the circuit board 133 of the light-emitting unit 130 can be arranged to replace part of the first part 111 of the carrier 110 to surround the accommodation space 113, so that the circuit board 133 connects the front frame 140 and the second part of the carrier 110 in the Z direction. The edge of 112.

Please refer to FIG. 4 , which is a schematic partial cross-sectional view of another variant embodiment according to the first embodiment of the present invention. The backlight module 100 further includes a main reflective sheet 160 . Main reflective sheet 160 accommodate in the accommodating space 113 and extends along the direction in which the light guide element 120 extends. In this modified embodiment, the reflective structure 153 is a part of the main reflective sheet 160 , that is to say, the main reflective sheet 160 and the reflective structure 153 are connected to each other. For example, the reflective structure 153 is a part of the main reflective sheet 160 that extends toward the light-emitting unit 130 to ensure uniformity of reflected light and achieve better light uniformity.

Please refer to FIG. 5 . FIG. 5 is a schematic partial cross-sectional view taken along the A-A’ section line of FIG. 1A according to the second embodiment of the present invention. The Y direction and the Z direction in FIG. 5 correspond to the Y direction and the Z direction shown in FIG. 1B respectively. In this embodiment, the circuit board 133 is arranged parallel to the light guide element 120, so that a part of the circuit board 133 extends between the carrier 110 and the light-emitting element 132, and the other part of the circuit board 133 extends to the carrier. 110 and the light guide element 120, and is fixed on the carrier 110. In more detail, the first glue layer 151 of the glue unit 150 is attached to the light guide element 120, and the second glue layer 152 is attached to the circuit board 133, so that the circuit board 133 is sandwiched between the second glue layer 152 and the carrier 110. between them, and are relatively fixed on the light guide element 120 and the carrier 110 .

For those who wish to clarify, the number of first parts, the shape of the second part, the shape of the light guide element, the type of the light-emitting unit, the number of the light-emitting unit, the color of the light, the material of the colloid unit, and the main body are mentioned in each embodiment of the present invention. The material of the reflective sheet, the thickness of the first adhesive layer, or the thickness of the second adhesive layer are only for illustration and are not intended to limit the present invention. In other embodiments, the shape, number, material, or thickness of the above-mentioned components can be changed according to requirements. In some embodiments, the reflective structure and the main reflective sheet may or may not be connected. The connected reflective structure and the main reflective sheet can be formed into an integrated structure, and its shape can be designed to match the shape of the accommodation space.

As can be seen from the above embodiments of the present invention, the present invention fixes the light guide element to the carrier through a colloid unit, in which the first glue layer is attached to the reflective surface and reflective structure of the light guide element, and the second glue layer is attached to the carrier components and reflective structures, and the first adhesive layer has the characteristics of lower transmittance, thereby reducing the amount of light passing through the light guide element through the first adhesive layer, not only achieving the design purpose of a narrow frame, but also taking into account the overall The optical quality of the light-emitting surface can, for example, reduce the occurrence of bright bands, hot spots or unevenness in the light-emitting area of the light guide element close to the light-incoming surface.

According to the experimental results shown in Figure 2, it can be known that the penetration rate of the first adhesive layer is no more than 85%. The penetration rate of the first adhesive layer can range from 40% to 85%. If the penetration rate of the first adhesive layer is less than 40%, it is easy to cause poor adhesion. If the penetration rate of the first adhesive layer exceeds 85%, the conventional problems of bright bands and hot spots will become obvious, which will affect the display. The overall visual look and feel of the device. The transmittance of the first adhesive layer is lower than the transmittance of the second adhesive layer, thereby reducing the problems of bright bands and hot spots in the conventional backlight module. The thickness of the first glue layer can be adjusted to be greater than the thickness of the second glue layer, thereby achieving the purpose of making the penetration rate of the first glue layer smaller than the penetration rate of the second glue layer. Alternatively, coloring matter can be added to the first glue layer to adjust the composition of the first glue layer, thereby achieving the purpose of making the transmittance of the first glue layer smaller than the transmittance of the second glue layer, thereby making the display device It has a better overall visual look and feel. The above are only preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the patentable scope of the present invention shall fall within the scope of the present invention.

10:Display device

100:Backlight module

110: Bearing part

111:Part One

111A:Top surface

112:Part 2

113: Accommodation space

114: Air gap

120:Light guide element

121: Light incident surface

122: Shiny surface

130:Light-emitting unit

131:Light

132:Light-emitting component

133:Circuit board

140:Front frame

150: Colloidal unit

151: First glue layer

151A:Light incident surface

152:Second glue layer

153: Reflective structure

200:Display panel

210: light-emitting surface

Claims (9)

A backlight module includes: a carrier having an accommodation space; a light guide element accommodated in the accommodation space and having a light incident surface; a light emitting unit disposed close to the light incident surface One side; and a colloid unit, which is disposed between the light guide element and the carrier, and includes a first glue layer, a second glue layer and a reflective structure, wherein the first glue layer is attached to the guide Optical element, at least part of the reflective structure is disposed between the first glue layer and the second glue layer, the transmittance of the first glue layer is 40%-85%, endpoint values included, and the first The penetration rate of the glue layer is smaller than the penetration rate of the second glue layer. The backlight module of claim 1, wherein the second adhesive layer is attached to the carrier. The backlight module of claim 1, wherein the light guide element has a reflective surface connected to the light incident surface, the backlight module further includes: a main reflective sheet, the main reflective sheet and the colloid unit are arranged on the between the reflective surface and the carrier, and the colloid unit is closer to the light-emitting unit than the main reflective sheet. The backlight module of claim 3, wherein the reflective structure is a part of the main reflective sheet extending toward the light-emitting unit. As for the backlight module of claim 1, the light-emitting unit further includes a plurality of light-emitting elements and a circuit board. The light-emitting elements are provided on the circuit board. A part of the circuit board extends to the carrier and the conductor. between the optical components, and the second adhesive layer is attached to the circuit board. The backlight module of claim 1, wherein the thickness of the first glue layer is greater than the thickness of the second glue layer. The backlight module of claim 1, wherein the first adhesive layer contains a color material. A display device includes: a backlight module as described in any one of claims 1 to 7; and a display panel disposed above the backlight module. The display device of claim 8, wherein the backlight module further includes: a front frame disposed between the light guide element and the display panel to carry the display panel.