CN220626818U - Backlight module and display device - Google Patents

Abstract

A backlight module and a display device using the same are provided. The backlight module comprises a light source, a light guide plate, a first optical film and a second optical film. The light incident surface of the light guide plate is opposite to the light source. The first optical film is arranged opposite to the light emergent surface of the light guide plate. The first plate body of the first optical film has a first surface facing the light-emitting surface. The first optical microstructures of the first optical film are arranged on the first surface, and two first inclined planes of the first optical microstructures respectively form a first included angle with the first surface, and the angle of the first included angle is 15-60 degrees. The second optical film is arranged on one side of the first optical film far away from the light guide plate. The second plate body of the second optical film is provided with a second surface far away from the first optical film, and the second optical microstructure of the second optical film is arranged on the second surface. The backlight module can improve the brightness and contrast of the light and maintain a wide enough visual angle.

Description

Backlight module and display device

Technical Field

The present utility model relates to a light source module, and more particularly to a backlight module and a display device using the same.

Background

The components of the liquid crystal display device mainly comprise a backlight module, a display panel, an outer frame and the like. The backlight module can be divided into an edge type backlight module and a direct type backlight module according to different light source directions. Generally, the edge-lit backlight module is configured with a light guide plate, and a light source is disposed at an edge of the light guide plate; the light guide plate can guide light beams generated by the light source to exit from the light emitting surface facing the display panel, so that a surface light source is formed.

Generally, for convenience of daily use, the viewing angle of the lcd device is often not too small. However, in order to provide a wide enough viewing angle, the backlight module is often additionally configured with an optical film with high haze, which results in a decrease of brightness and contrast of the backlight module. In addition, since part of the light beam is emitted from the backlight module at a larger angle, the light beam can cause light leakage of the display panel in a dark state.

The background section is only for the purpose of aiding in the understanding of the subject matter so that the disclosure of this background section may contain some of the known art that does not form part of the knowledge of one of ordinary skill in the art. Furthermore, nothing disclosed in the "background" is intended to represent such disclosure or problems to be solved by one or more embodiments of the present utility model, nor is it intended to represent such disclosure as would be known or appreciated by one of ordinary skill in the art prior to the present utility model.

Disclosure of Invention

The present utility model provides a backlight module to improve brightness and contrast of light output and maintain a wide enough visual angle.

The present utility model provides a display device to improve the image quality and improve the dark state light leakage.

Other objects and advantages of the present composition will be further appreciated from the technical features disclosed in the present composition.

In order to achieve one or a part or all of the above objects or other objects, the present utility model provides a backlight module comprising a light source, a light guide plate, a first optical film and a second optical film. The light guide plate is provided with a light incident surface and a light emergent surface which are connected. The light incident surface is arranged opposite to the light source. The first optical film is arranged opposite to the light emergent surface. The first optical film has a first plate body and a plurality of first optical microstructures. The first plate body is provided with a first surface facing the light-emitting surface. The first optical microstructures are arranged on the first surface, and each of the first optical microstructures extends on the first surface along the first direction. The first optical microstructures have two first inclined planes, respectively, and each of the two first inclined planes has a first end and a second end which are opposite. The first ends of the two first inclined planes of each of the first optical microstructures are respectively arranged on the first surfaces, and a first included angle is formed between the two first inclined planes and the first surfaces, wherein the angle of the first included angle is 15-60 degrees. The second optical film is arranged on one side of the first optical film far away from the light guide plate. The second optical film has a second plate body and a plurality of second optical microstructures. The second plate body is provided with a second surface far away from the first optical film. The second optical microstructures are arranged on the second surface, and each of the second optical microstructures extends on the second surface along the second direction.

In an embodiment of the present utility model, the first included angle of each of the first optical microstructures may be between 36 ° and 60 °.

In an embodiment of the present disclosure, the two second ends of the two first inclined planes of each of the first optical microstructures are connected to each other to form a first vertex angle, and the angle of the first vertex angle is, for example, between 100 ° and 150 °.

In an embodiment of the present utility model, the first vertex angle may include a sharp corner or a rounded corner.

In an embodiment of the present utility model, an angle between the first direction and a normal direction of the light incident surface may be less than or equal to 15 °.

In an embodiment of the present utility model, an angle between the first direction and the second direction is, for example, 75 ° to 105 °.

In an embodiment of the present utility model, each of the first optical microstructures may further have two second slopes. The two second inclined planes are respectively provided with a third end and a fourth end which are opposite, and the third end is adjacent to the second end of the first inclined plane. The two fourth ends of the two second inclined planes are connected with each other to form a second apex angle, and a second included angle is formed between the second inclined planes and the first surface. The second included angle is smaller than the first included angle, for example.

In an embodiment of the present utility model, the angle of the second vertex angle may be between 100 ° and 150 °.

In an embodiment of the present utility model, the second vertex angle includes a sharp corner or a rounded corner.

In an embodiment of the present utility model, the first optical film may include a plurality of first light-diffusing particles, and the first light-diffusing particles are disposed on a third surface of the first plate body away from the light guide plate.

In an embodiment of the present disclosure, the first optical film may include a plurality of reflective particles disposed in the first optical microstructure.

In an embodiment of the present utility model, the second optical film may include a plurality of second light-diffusing particles, and the second light-diffusing particles are disposed on a fourth surface of the second optical film facing the first optical film.

In an embodiment of the present disclosure, the first optical film includes a plurality of elastic fillers, and the elastic fillers are disposed in the first optical microstructure.

In an embodiment of the present utility model, the light guide plate may further have a plurality of columns. The columns are arranged on the light-emitting surface, and each column extends on the light-emitting surface along the third direction.

In an embodiment of the present disclosure, the backlight module further includes a diffusion sheet disposed between the light guide plate and the first optical film.

In an embodiment of the present disclosure, the backlight module may further include a reflective brightness enhancement film, and the reflective brightness enhancement film is disposed on a side of the second optical film away from the first optical film.

In an embodiment of the present disclosure, the backlight module may further include a reflective sheet disposed on a side of the light guide plate away from the first optical film.

In order to achieve one or a part or all of the above objects or other objects, the display device provided by the present utility model includes the above backlight module and a display panel. The display panel is arranged on one side of the second optical film far away from the first optical film and is overlapped on the light emitting surface of the light guide plate.

The backlight module of the creation adopts a first optical film and a second optical film, wherein the first optical film can concentrate the solid angle of light beam emergence through a first optical microstructure. In addition, the second optical microstructure of the second optical film can not only concentrate the vertical opening angle of the light beam emergent, thereby improving the light collecting property of the light beam at the vertical opening angle, but also increase the light emergent brightness of the light beam in the horizontal viewing angle range, so that the backlight module can provide a wide enough visible angle. Based on the structure, the backlight module can improve the brightness and the contrast ratio and simultaneously maintain a wide enough visual angle. Because the display device of the present utility model adopts the backlight module, the image quality can be improved. In addition, the backlight module can concentrate the solid angle of light beam emergence, so the problem of light leakage of the display device in a dark state can be improved.

The foregoing and other objects, features and advantages of the present utility model will be more readily apparent from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a schematic side view of a backlight module according to an embodiment of the present disclosure.

Fig. 2 is a schematic perspective view of the first and second optical films of fig. 1.

FIG. 3 is an enlarged schematic view of a portion of a first optical microstructure of the first optical film of FIG. 1.

Fig. 4 is a schematic enlarged view of a portion of a first optical film of a backlight module according to another embodiment of the present disclosure.

Fig. 5 is a partial schematic top view of the first and second optical films of fig. 2.

FIG. 6 is a schematic diagram of a light-emitting field pattern of the first optical film of FIG. 1.

Fig. 7 is a schematic diagram showing the distribution of brightness of the vertical viewing angle after the first optical film and the second optical film of fig. 1 are stacked.

Fig. 8 is a schematic diagram showing the distribution of the luminance of the horizontal viewing angle after the first optical film and the second optical film of fig. 1 are stacked.

Fig. 9 is a schematic enlarged view of a portion of a first optical film of a backlight module according to another embodiment of the present disclosure.

Fig. 10 is a schematic enlarged view of a portion of a first optical film of a backlight module according to another embodiment of the present disclosure.

Fig. 11 is a schematic side view of a backlight module according to another embodiment of the present disclosure.

Fig. 12 is a schematic side view of a backlight module according to another embodiment of the present disclosure.

Fig. 13 is a schematic side view of a backlight module according to another embodiment of the present disclosure.

Fig. 14 is a schematic side view of a backlight module according to another embodiment of the present disclosure.

Fig. 15 is a schematic side view of a backlight module according to another embodiment of the present disclosure.

Fig. 16 is a perspective view of the light source and the light guide plate of fig. 15.

Fig. 17 is a schematic side view of a backlight module according to another embodiment of the present disclosure.

Fig. 18 is a schematic side view of a display device of an embodiment of the present disclosure.

FIG. 19 is a diagram illustrating a light-emitting field of a conventional display device and a light-emitting field of a display device according to an embodiment of the present disclosure.

Reference numerals illustrate:

100. 100b, 100c, 100d, 100e, 100f, 100g, 100h, 100i: backlight module 110: light source

120. 120h: light guide plate

121: light incident surface

122: light-emitting surface

123: column body

130. 130a, 130b, 130c, 130d, 130e, 130g: first optical film

131: first plate body

132. 132a, 132b, 132c: first optical microstructure

133: reflective particles

133e: first light scattering particle

134: elastic filler

140. 140f: second optical film

141: second plate body

142: second optical microstructure

143: second light scattering particles

150: reflection sheet

160: diffusion sheet

170: reflective brightness enhancement film

200: display device

210: display panel

A1: first included angle

A2: second included angle

D1: first direction

D2: second direction

D3: third direction of

E10, E11, E21: first end

E20, E21: second end

E30, E31: third end

E40, E41: fourth end

IA: included angle

L1, L2: longest edge

N: normal direction

S1: a first surface

S10, S11: first inclined plane

S2: a second surface

S20, S21: second inclined plane

S3: third surface

S4: fourth surface

TA1: first apex angle

TA2: second apex angle

Z1a, Z2a, Z1b, Z2b: region(s)

θ1, θ2, θ2b, θ2c: angle of

X, Y, Z: direction.

Detailed Description

The foregoing and other technical content, features and effects of the present utility model will be apparent from the following detailed description of the preferred embodiments with reference to one of the accompanying drawings. The directional terms mentioned in the following embodiments are, for example: upper, lower, left, right, front or rear, etc., are merely references to the directions of the attached drawings. Thus, directional terminology is used for purposes of illustration and is not intended to be limiting.

Fig. 1 is a schematic side view of a backlight module according to an embodiment of the present disclosure. Fig. 2 is a schematic perspective view of the first and second optical films of fig. 1. FIG. 3 is an enlarged schematic view of a portion of a first optical microstructure of the first optical film of FIG. 1. Referring to fig. 1 and 2, the backlight module 100 includes a light source 110, a light guide plate 120, a first optical film 130 and a second optical film 140. The light guide plate 120 has a light incident surface 121 and a light emergent surface 122 connected to each other. The light incident surface 121 is disposed opposite to the light source 110. The first optical film 130 is disposed opposite to the light-emitting surface 122. The first optical film 130 has a first plate 131 and a plurality of first optical microstructures 132. The first plate 131 has a first surface S1 facing the light-emitting surface 122. The first optical microstructures 132 are disposed on the first surface S1, and each of the first optical microstructures 132 extends along the first direction D1 on the first surface S1, wherein the first direction D1 of the present embodiment is substantially parallel to the direction X, and each of the first optical microstructures 132 is arranged along the second direction D2 (shown in fig. 2) on the first surface S1, wherein the second direction D2 of the present embodiment is substantially parallel to the direction Y, but the present disclosure is not limited thereto. Referring to fig. 2 and 3, in the present embodiment, the first optical microstructure 132 has a first inclined surface S10 and S11, respectively, wherein the first inclined surface S10 has a first end E10 and a second end E20 opposite to each other, and the first inclined surface S11 has a first end E11 and a second end E21 opposite to each other. The first ends E10 and E11 are respectively arranged on the first surface S1, and a first included angle A1 is formed between the first inclined surfaces S10 and S11 and the first surface S1, wherein the angle of the first included angle A1 is 15-60 degrees; it should be further noted that, if the angle of the first included angle A1 is further limited to 36 ° to 60 °, the solid angle of the light beam exiting from the first optical film 130 can be further concentrated, so as to further improve the brightness of the backlight module 100. Referring to fig. 1 and 2 again, the second optical film 140 is disposed on a side of the first optical film 130 away from the light guide plate 120. The second optical film 140 has a second plate 141 and a plurality of second optical microstructures 142. The second plate 141 has a second surface S2 remote from the first optical film 130. The second optical microstructures 142 are disposed on the second surface S2, and each of the second optical microstructures 142 extends along the second direction D2 on the second surface S2, and each of the second optical microstructures 142 is arranged along the first direction D1 on the second surface S2, wherein the first direction D1 of the present embodiment is substantially parallel to the direction X, for example, but the present disclosure is not limited thereto.

With continued reference to fig. 1, the light source 110 of the present embodiment may include a plurality of Light Emitting Diodes (LEDs), and the LEDs may be arranged along a long side direction (e.g., a direction Y) of the light incident surface 121. Further, the light emitting wavelength of the aforementioned led may include blue light or white light, but the present utility model is not limited thereto.

The material of the light guide plate 120 may include plastic, glass or other materials suitable for light penetration. For example, in the present embodiment, the material of the light guide plate 120 may include polymethyl methacrylate (Polymethyl methacrylate, PMMA); however, in other embodiments, the material of the light guide plate 120 may include a cycloolefin polymer (Cyclo olefin polymer, COP) or a Polycarbonate (PC). In addition, the light guide plate 120 of the present embodiment may be manufactured by hot press molding or injection molding, but the present utility model is not limited thereto.

Referring to fig. 1 and fig. 2 together, in the present embodiment, the first optical microstructure 132 of the first optical film 130 may be in a column shape, and the first direction D1 may be an axial direction or an extending direction of a long side of the first optical microstructure 132. For example, the first optical microstructure 132 may be a triangular prism, and the first direction D1 may be a direction (e.g., the direction X) in which the longest side L1 of the triangular prism extends. The angle between the first direction D1 and the normal direction N of the light incident surface 121 may be less than or equal to 15 °. For example, in the present embodiment, the first direction D1 and the normal direction N of the light incident surface 121 are substantially parallel to the direction X, and the included angle is about 0 °, but the present utility model is not limited to the value of the included angle.

Referring to fig. 2 and 3 again, in the present embodiment, the second end E20 of the first inclined surface S10 and the second end E21 of the first inclined surface S11 are connected to each other to form a first vertex angle TA1, and the angle θ1 of the first vertex angle TA1 is, for example, between 100 ° and 150 °, so that the solid angle of the light beam exiting from the first optical film 130 can be more concentrated, and the brightness of the backlight module 100 can be further improved. Specifically, the first apex angle TA1 of the present embodiment may include a sharp angle, and the angle θ1 of the sharp angle may be between 100 ° and 150 °. It should be further noted that, when the shape of the first optical microstructure 132 is a triangle, the angle of the first included angle A1 of the first optical microstructure 132 may be between 15 ° and 40 °.

Fig. 4 is a schematic enlarged view of a portion of a first optical film of a backlight module according to another embodiment of the present disclosure. In the embodiment of fig. 4, the structure and advantages of the first optical film 130a of the backlight module 100a are similar to those of the embodiment of fig. 3, and only differences are described below. The first vertex angle TA1 of the first optical microstructure 132a of the first optical film 130a may include a rounded corner, and the angle θ1 shown in fig. 3 corresponds to the angle θ2 between the second end E20 of the first inclined surface S10 and the second end E21 of the first inclined surface S11 in fig. 4, and the angle θ2 may be between 100 ° and 150 °.

Fig. 5 is a partial schematic top view of the first and second optical films of fig. 2. Referring to fig. 2 and fig. 5 together, the second optical microstructure 142 of the second optical film 140 may be in a column shape, and the second direction D2 may be an axial direction or an extending direction of a long side of the second optical microstructure 142. For example, the second optical microstructure 142 may be a triangular prism, and the second direction D2 may be a direction (e.g., the direction Y) in which the longest side L2 of the triangular prism extends. The angle IA (shown in fig. 5) between the first direction D1 and the second direction D2 is, for example, 75 ° to 105 °, so as to concentrate the solid angle at which the light beam exits from the second optical film 140. In the present embodiment, the angle IA is about 90 °, for example, but the present utility model is not limited thereto.

Compared to the prior art, the backlight module 100 of the present embodiment employs the first optical film 130 and the second optical film 140, wherein the first optical film 130 can concentrate the solid angle of the light beam exiting through the first optical microstructure 132. In addition, the second optical microstructure 142 of the second optical film 140 not only can concentrate the vertical opening angle of the light beam, thereby improving the light collecting property of the light beam at the vertical opening angle, but also can increase the light emitting brightness of the light beam in the horizontal viewing angle range, so that the backlight module 100 can provide a sufficiently wide visible angle. Based on the above structure, the backlight module 100 of the present embodiment can improve the brightness and contrast of the light emitted and maintain a wide enough viewing angle.

FIG. 6 is a schematic diagram of a light-emitting field pattern of the first optical film of FIG. 1. Fig. 7 is a schematic diagram showing the distribution of brightness of the vertical viewing angle after the first optical film and the second optical film of fig. 1 are stacked. Fig. 8 is a schematic diagram showing the distribution of the luminance of the horizontal viewing angle after the first optical film and the second optical film of fig. 1 are stacked. It should be noted that, fig. 6 illustrates the light intensity with the distribution density of the net points, wherein the higher the distribution density of the net points in the net bottom pattern, the stronger the light emitting intensity of the area; conversely, the lower the distribution density of the network points in the network bottom pattern, the weaker the outgoing light intensity of the area. In addition, fig. 7 and 8 illustrate the distribution of the luminance of the backlight module according to the prior art by a dashed line, and illustrate the distribution of the luminance of the backlight module according to the present embodiment by a solid line, it should be further noted that the prism sheet used in the prior art comprises only one positive prism sheet (the optical microstructure is disposed on the side of the prism sheet away from the light guide plate), and the prism sheet used in the backlight module according to the present embodiment comprises the first optical film 130 and the second optical film 140. Referring to fig. 6, fig. 6 shows that after the light beam emitted from the light emitting surface 122 of the light guide plate 120 is transmitted to the first optical film 130, the light beam emitted from the first optical film 130 is emitted, and as can be seen from fig. 6, the first optical film 130 (shown in fig. 1) can concentrate the solid angle of the light beam to a range. Referring to fig. 7 and 8, fig. 7 and 8 are schematic views showing the brightness distribution of the vertical and horizontal viewing angles of the light beam emitted from the first optical film 130 after being transmitted to the second optical film 140, and as shown in fig. 7, compared with the conventional backlight module, the backlight module 100 (shown in fig. 1) of the present embodiment can enhance the light collecting performance of the vertical viewing angle, thereby enhancing the brightness and contrast ratio. In addition, as shown in fig. 8, the backlight module 100 can further enhance the brightness of the light emitted from the backlight module 100 within a horizontal viewing angle range, so as to further increase the brightness and contrast of the light emitted from the backlight module 100 and provide a wide enough viewing angle.

Referring to fig. 1 again, the backlight module 100 may further include a reflective sheet 150. The reflective sheet 150 is disposed on a side of the light guide plate 120 away from the first optical film 130 to increase light utilization. The material of the reflection sheet 150 may include silver, but the present utility model is not limited thereto.

Fig. 9 is a schematic enlarged view of a portion of a first optical film of a backlight module according to another embodiment of the present disclosure. Fig. 10 is a schematic enlarged view of a portion of a first optical film of a backlight module according to another embodiment of the present disclosure. In the embodiment of fig. 9 and 10, the structure and advantages of the first optical film 130b of the backlight module 100b and the first optical film 130c of the backlight module 100c are similar to those of the embodiment of fig. 1, and only differences are described below. Referring to fig. 9, the first optical microstructures 132b of the first optical film 130b may further have second slopes S20 and S21, respectively. The second inclined surface S20 has a third end E30 and a fourth end E40 opposite to each other, and the second inclined surface S21 has a third end E31 and a fourth end E41 opposite to each other. The third end E30 is adjacent to the second end E20 of the first inclined surface S10, and the third end E31 is adjacent to the second end E21 of the first inclined surface S11. The fourth ends E40 and E41 are connected to each other to form a second apex angle TA2, and the second inclined surfaces S20 and S21 respectively form a second included angle A2 with the first surface S1. The second angle A2 is smaller than the first angle A1, for example. Thus, the solid angle of the light beam emitted from the first optical film 130b can be further concentrated, so as to further improve the brightness of the backlight module 100 b. Specifically, the first inclined surfaces S10 and S11 and the second inclined surfaces S20 and S21 have slopes (gradients) with respect to the first surface S1, and the first inclined surface S10 and the second inclined surface S20 are described below, and the characteristics of the first inclined surface S11 and the second inclined surface S21 are the same as those of the first inclined surface S10 and the second inclined surface S20. Further, the first slope S10 has a first slope with respect to the first surface S1, and the second slope S20 has a second slope with respect to the first surface S1, wherein the absolute value of the first slope is greater than the absolute value of the second slope. In an embodiment, the angle θ2b of the second vertex angle TA2 may be between 100 ° and 150 °, so as to further concentrate the solid angle of the light beam exiting from the first optical film 130b and further enhance the brightness of the backlight module 100 b. Similarly, the second apex angle TA2 of the present embodiment includes, for example, a sharp angle, and the angle θ2b of the sharp angle may be between 100 ° and 150 °. In another embodiment, such as the backlight module 100c shown in fig. 10, the second vertex angle TA2 of the first optical film 130c may include rounded corners; in detail, the angle θ2b in fig. 9 corresponds to the angle θ2c in fig. 10, wherein the angle θ2c is an angle between the fourth end E40 of the second inclined surface S20 and the fourth end E41 of the second inclined surface S21, and the angle θ2c may be between 100 ° and 150 °. Incidentally, referring to fig. 9 and 10 together, the shape of the first optical microstructures 132b and 132c may include pentagonal columns, but other embodiments are not limited thereto.

Fig. 11 is a schematic side view of a backlight module according to another embodiment of the present disclosure. The structure and advantages of the backlight module 100d of the present embodiment are similar to those of the embodiment of fig. 1, and only differences are described below. Referring to fig. 11, the first optical film 130d may include a plurality of first light-diffusing particles 133, where the first light-diffusing particles 133 are disposed on the third surface S3 of the first plate 131 away from the light guide plate 120. In detail, the third surface S3 is opposite to the first surface S1, and the third surface S3 faces the second optical film 140. In addition, the first light-diffusing particles 133 can allow the light beam to pass through, so that the brightness of the light emitted from the third surface S3 can be more uniform, and the uniformity of the light emitted from the backlight module 100d can be further improved. In this embodiment, the first light-diffusing particles 133 are integrally formed with the first plate 131, for example. Further, the first light-diffusing particles 133 may be formed on the third surface S3 by thermo-compression molding, but the present utility model is not limited thereto. It should be further noted that, the third surface S3 of the first plate 131 faces the second plate 141 of the second optical film 140, and by disposing the first light-diffusing particles 133 on the third surface S3, the first optical film 130d is prevented from being absorbed to the second optical film 140.

Fig. 12 is a schematic side view of a backlight module according to another embodiment of the present disclosure. The structure and advantages of the backlight module 100e of the present embodiment are similar to those of the embodiment of fig. 1, and only differences are described below. Referring to fig. 12, the first optical film 130e may include a plurality of reflective particles 133e, where the reflective particles 133e are disposed in the first optical microstructure 132. Specifically, the reflective particles 133e can reflect the light beam, so that the brightness of the light emitted from the first optical film 130e can be more uniform, and the uniformity of the light emitted from the backlight module 100e can be further improved. In this embodiment, the material of the reflective particles 133e may include plastic and be in a separate structure from the first optical microstructure 132. Further, the reflective particles 133e may be mixed with the material of the first optical microstructure 132, and then the reflective particles 133e are fixed in the first optical microstructure 132 by hot press molding or injection molding. However, the present disclosure does not limit the manufacturing process of the first optical film 130 e.

Fig. 13 is a schematic side view of a backlight module according to another embodiment of the present disclosure. The structure and advantages of the backlight module 100f of the present embodiment are similar to those of the embodiment of fig. 1, and only differences are described below. Referring to fig. 13, the second optical film 140f may include a plurality of second light-diffusing particles 143, where the second light-diffusing particles 143 are disposed on the fourth surface S4 of the second optical film 140f facing the first optical film 130. In detail, the fourth surface S4 is opposite to the second surface S2, and the second light-diffusing particles 143 can pass through the light beam; thus, the brightness of the light emitted from the second optical film 140f can be more uniform, so as to further improve the uniformity of the light emitted from the backlight module 100 f. In the present embodiment, the second light scattering particles 143 are integrally formed with the second plate 141, for example. Further, the second light-diffusing particles 143 may be formed on the fourth surface S4 by thermo-compression molding, but the present utility model is not limited thereto. It should be further noted that, the fourth surface S4 of the second plate 141 faces the first plate 131 of the first optical film 130, and by disposing the second light-scattering particles 143 on the fourth surface S4, the first optical film 130 is prevented from being absorbed to the second optical film 140f.

Fig. 14 is a schematic side view of a backlight module according to another embodiment of the present disclosure. The structure and advantages of the backlight module 100g of the present embodiment are similar to those of the embodiment of fig. 1, and only differences are described below. Referring to fig. 14, the first optical film 130g includes a plurality of elastic fillers 134, and the elastic fillers 134 are disposed in the first optical microstructure 132. In detail, when the first optical film 130g is pressed by an external force, the elastic filler 134 is more easily deformed than the first optical microstructure 132, so that the elastic filler 134 can slow down the external force applied to the first optical microstructure 132, and further prevent the surface of the first optical microstructure 132 from being damaged by the external force to leave marks. In this embodiment, the material of the elastic filler 134 may include plastic, silica gel or rubber; the elastic filler 134 may be a gel including the above-described materials. Further, the elastic filler 134 may be mixed in the photosensitive resin, and then the photosensitive resin is disposed on the first plate 131, and the first optical microstructure 132 is formed by compression molding or roll molding (roller pressure molding process), and the elastic filler 134 is fixed in the first optical microstructure 132.

Fig. 15 is a schematic side view of a backlight module according to another embodiment of the present disclosure. Fig. 16 is a perspective view of the light source and the light guide plate of fig. 15. The structure and advantages of the backlight module 100h of the present embodiment are similar to those of the embodiment of fig. 1, and only differences are described below. Referring to fig. 15 and 16, the light guide plate 120h may further have a plurality of columns 123. The pillars 123 are disposed on the light-emitting surface 122, and each of the pillars 123 extends along the third direction D3 on the light-emitting surface 122. In detail, the column 123 can pass through the light beam and raise the brightness of the light beam; thus, the brightness of the light emitted from the light guide plate 120h can be further improved, so as to further improve the brightness of the light emitted from the backlight module 100 h. In the present embodiment, the third direction D3 is, for example, substantially parallel to the extending direction of the longest side of the cylinder 123, and fig. 16 illustrates the extending direction in the direction X. Further, the third direction D3 is substantially perpendicular to the light incident surface 121, but the present utility model is not limited thereto. In addition, referring to fig. 16, in the present embodiment, the light sources 110 and the columns 123 may be arranged along the same direction; for example, the light sources 110 are disposed side by side with each other along the direction Y, and the columns 123 are disposed side by side with each other along the direction Y.

Fig. 17 is a schematic side view of a backlight module according to another embodiment of the present disclosure. The structure and advantages of the backlight module 100i of the present embodiment are similar to those of the embodiment of fig. 1, and only differences are described below. Referring to fig. 17, the backlight module 100i further includes a diffusion sheet 160 (diffuser), where the diffusion sheet 160 is disposed between the light guide plate 120 and the first optical film 130, so as to further improve the uniformity of light emitted from the backlight module 100i. In addition, the backlight module 100i may further include a reflective brightness enhancement film 170 (dual brightness enhancement film, DBEF), wherein the reflective brightness enhancement film 170 is disposed on a side of the second optical film 140 away from the first optical film 130, so as to further enhance the light utilization of the backlight module 100i. It is understood that the diffuser 160 and the reflective brightness enhancing film 170 can be separately disposed, and the diffuser 160 and the reflective brightness enhancing film 170 are not limited to be disposed in the same embodiment. In other embodiments, the backlight module 100i can be configured with other different types of optical films, which is not limited in this disclosure.

Fig. 18 is a schematic side view of a display device of an embodiment of the present disclosure. Referring to fig. 18, the display device 200 includes a backlight module 100 and a display panel 210. The display panel 210 is disposed on a side of the second optical film 140 away from the first optical film 130, and overlaps the light emitting surface 122 of the light guide plate 120. In other words, the display panel 210 may be disposed opposite to the second surface S2 of the second optical film 140. In this embodiment, the display panel 210 may include a liquid crystal display panel, and the backlight module 100 can provide light to the display panel 210. However, the present embodiment does not limit the variety of the display panel 210. Incidentally, in other embodiments, the display device 200 may employ the backlight modules 100a, 100b, 100c, 100d, 100e, 100f, 100g, 100h or 100i described above.

Compared with the prior art, the display device 200 of the present embodiment adopts the backlight module 100, so that the image quality can be improved. In addition, since the backlight module 100 can concentrate the solid angle of the light beam, the problem of light leakage of the display device 200 in the dark state can be improved. Incidentally, referring to fig. 8 and 18 together, since the backlight module 100 can increase the brightness of the display device 200 in a horizontal viewing angle range (e.g. about 30 ° to 55 °), in the embodiment in which the display panel 210 employs a liquid crystal display panel, the display device 200 can also meet the requirements of TCO Certification (TCO).

FIG. 19 is a diagram illustrating a light-emitting field of a conventional display device and a light-emitting field of a display device according to an embodiment of the present disclosure. Similarly, FIG. 19 illustrates light intensity in terms of the distribution density of the dots, where the higher the distribution density of the dots in the mesh base pattern, the stronger the light exiting the region; conversely, the lower the distribution density of the net points in the net bottom pattern is, the weaker the emergent light intensity of the area is; it should be further noted that, the prism sheet used in the backlight module of the conventional display device includes only one positive prism sheet (the optical microstructure is disposed on the side of the prism sheet away from the light guide plate), and the prism sheet used in the backlight module of the display device of the present embodiment includes the first optical film 130 and the second optical film 140. Referring to fig. 19, (a) is a light-emitting field type of a conventional display device, and (a) illustrates a region with a larger light angle by regions Z1a and Z2 a. In addition, (b) is the light-emitting field type of the display device 200 according to the embodiment of the present disclosure, and (b) indicates the regions with larger light angles by the regions Z1b and Z2 b. Compared with the light output intensity of the light output field type in the regions Z1a and Z2a of the known display device, the light output intensity of the light output field type in the regions Z1b and Z2b of the display device 200 of the present utility model is significantly reduced, thereby improving the dark state light leakage problem. Incidentally, in fig. 19, (a) and (b) show angles represented by a plurality of concentric circles as shown in fig. 6.

In summary, the backlight module of the present utility model employs the first optical film and the second optical film, wherein the first optical film can concentrate the solid angle of the light beam emitted by the first optical microstructure. In addition, the second optical microstructure of the second optical film can not only concentrate the vertical opening angle of the light beam emergent, thereby improving the light collecting property of the light beam at the vertical opening angle, but also increase the light emergent brightness of the light beam in the horizontal viewing angle range, so that the backlight module can provide a wide enough visible angle. Based on the structure, the backlight module can improve the brightness and the contrast ratio and simultaneously maintain a wide enough visual angle. Because the display device of the present utility model adopts the backlight module, the image quality can be improved. In addition, the backlight module can concentrate the solid angle of light beam emergence, so the problem of light leakage of the display device in a dark state can be improved.

The foregoing description is only illustrative of the preferred embodiments of the present utility model and is not intended to limit the scope of the utility model, i.e., all simple and equivalent changes and modifications that may be made in accordance with the appended claims and their novel forms are to be embraced by the present utility model. Furthermore, no single embodiment or claim of the subject innovation is intended to achieve all of the objects or advantages or features disclosed by the subject innovation. Furthermore, the abstract and the title of the utility model are only used to assist in patent document retrieval, and are not intended to limit the scope of the claims of this patent. Furthermore, references to "first," "second," etc. in this specification or in the claims are only intended to name an element or distinguish between different embodiments or ranges, and are not intended to limit the upper or lower limit on the number of elements.

Claims (17)

1. A backlight module comprises a light source, a light guide plate, a first optical film and a second optical film:

the light guide plate is provided with a light incident surface and a light emergent surface which are connected, and the light incident surface is opposite to the light source;

the first optical film is arranged opposite to the light emitting surface, the first optical film is provided with a first plate body and a plurality of first optical microstructures, the first plate body is provided with a first surface facing the light emitting surface, the plurality of first optical microstructures are arranged on the first surface, each of the plurality of first optical microstructures extends to the first surface along a first direction, each of the plurality of first optical microstructures is provided with two first inclined planes, each of the two first inclined planes is provided with a first end and a second end which are opposite, the first ends of the two first inclined planes of each of the plurality of first optical microstructures are respectively arranged on the first surface, and a first included angle is formed between the two first inclined planes and the first surface, wherein the first included angle is 15-60 degrees; and

the second optical film is arranged on one side, far away from the light guide plate, of the first optical film, the second optical film is provided with a second plate body and a plurality of second optical microstructures, the second plate body is provided with a second surface far away from the first optical film, the plurality of second optical microstructures are arranged on the second surface, and each of the plurality of second optical microstructures extends to the second surface along a second direction.

2. The backlight module according to claim 1, wherein the first included angle of each of the plurality of first optical microstructures is between 36 ° and 60 °.

3. The backlight module of claim 1, wherein the two second ends of the two first slopes of each of the plurality of first optical microstructures are connected to each other to form a first vertex angle, the first vertex angle having an angle ranging from 100 ° to 150 °.

4. A backlight module according to claim 3, wherein the first vertex angle comprises a sharp or rounded corner.

5. The backlight module according to claim 1, wherein an angle between the first direction and a normal direction of the light incident surface is less than or equal to 15 °.

6. The backlight module according to claim 1, wherein an included angle between the first direction and the second direction is between 75 ° and 105 °.

7. The backlight module of claim 1, wherein the plurality of first optical microstructures further have two second inclined planes, respectively, the two second inclined planes have third and fourth opposite ends, respectively, the third end is adjacent to the second end of the first inclined plane, the two fourth ends of the two second inclined planes are connected to each other to form a second apex angle, and a second included angle is formed between the second inclined plane and the first surface, and the second included angle is smaller than the first included angle.

8. The backlight module according to claim 7, wherein the angle of the second vertex angle is between 100 ° and 150 °.

9. The backlight module of claim 7, wherein the second vertex angle comprises a sharp or rounded corner.

10. The backlight module according to claim 1, wherein the first optical film comprises a plurality of first light-diffusing particles disposed on a third surface of the first plate body away from the light guide plate.

11. The backlight module of claim 1, wherein the first optical film comprises a plurality of reflective particles disposed within the plurality of first optical microstructures.

12. The backlight module according to claim 1, wherein the second optical film comprises a plurality of second light-diffusing particles disposed on a fourth surface of the second optical film facing the first optical film.

13. The backlight module according to claim 1, wherein the light guide plate further comprises a plurality of columns disposed on the light emitting surface, and each of the columns extends along a third direction to the light emitting surface.

14. The backlight module according to claim 1, further comprising a diffusion sheet disposed between the light guide plate and the first optical film.

15. The backlight module of claim 1, further comprising a reflective brightness enhancement film disposed on a side of the second optical film remote from the first optical film.

16. The backlight module according to claim 1, further comprising a reflective sheet disposed on a side of the light guide plate away from the first optical film.

17. A display device comprises a backlight module and a display panel:

the backlight module comprises a light source, a light guide plate, a first optical film and a second optical film:

the light guide plate is provided with a light incident surface and a light emergent surface which are connected, and the light incident surface and the light source are arranged oppositely;

the first optical film is arranged opposite to the light emitting surface, the first optical film is provided with a first plate body and a plurality of first optical microstructures, the first plate body is provided with a first surface facing the light emitting surface, the plurality of first optical microstructures are arranged on the first surface, each of the plurality of first optical microstructures extends on the first surface along a first direction, each of the plurality of first optical microstructures is provided with two first inclined planes, each of the two first inclined planes is provided with a first end and a second end which are opposite, the first ends of the two first inclined planes of each of the plurality of first optical microstructures are respectively arranged on the first surface, and a first included angle is formed between each of the first optical microstructures and the first surface, and the two first included angles are respectively 15-60 degrees; and

the second optical film is arranged on one side, far away from the light guide plate, of the first optical film, the second optical film is provided with a second plate body and a plurality of second optical microstructures, the second plate body is provided with a second surface far away from the first optical film, the plurality of second optical microstructures are arranged on the second surface, and each of the plurality of second optical microstructures extends on the second surface along a second direction; and

the display panel is arranged on one side of the second optical film far away from the first optical film and is overlapped on the light emitting surface of the light guide plate.