Backlight module

Abstract

The present invention discloses a backlight module, which includes three light-emitting elements, a reverse prism lens, and a light guide assembly. The light guide assembly is disposed opposite to the reverse prism lens, and the light guide assembly includes a first light guide plate, a second light guide plate, and a third light guide plate. The first surface of the first light guide plate is located on the side facing away from the reverse prism lens. A first concave eye structure is formed on the first surface, and a connection line between two first eye corners of the first concave eye structure forms a first major axis. The second surface of the second light guide plate is located on the side facing away from the reverse prism lens. A second concave eye structure is formed on the second surface, and a connection line between two second eye corners of the second concave eye structure forms a second major axis. The third surface of the third light guide plate is located on the side facing away from the reverse prism lens. A third concave eye structure is formed on the third surface, and a connection line between two third eye corners of the third concave eye structure forms a third major axis. The positive projections of the second major axis and the third major axis on the first surface are inclined toward opposite sides of the reference direction respectively.

Description

Technical Field

[0001] The present invention relates to a light source module, and more particularly to a backlight module. Background Art

[0002] Liquid crystal displays mainly include a backlight module, a display panel, and a frame, etc. According to the different directions of the light-emitting elements, the backlight module can be further divided into a side-light type backlight module and a direct-lit type backlight module. Further, the side-light type backlight module has the advantages of thin thickness and low cost, so the screens using the side-light type backlight module have been widely used in daily life.

[0003] Since many electronic products in daily life are equipped with screens, and the above-mentioned electronic products are also widely used in work or public places, in order to prevent the information on the screen from being peeked by others, many screens will additionally provide an anti-peeking function. However, most of the existing anti-peeking functions are achieved by reducing the light-emitting brightness of the backlight module, resulting in poor image quality of the screen. Summary of the Invention

[0004] The present invention provides a backlight module to provide a multi-view switching function and narrow the overall light-emitting angle without reducing the light-emitting brightness.

[0005] The backlight module provided by the present invention includes a first light-emitting element, a second light-emitting element, a third light-emitting element, an inverse prism lens, and a light guide assembly. The light guide assembly is disposed opposite to the inverse prism lens. The light guide assembly includes a first light guide plate, a second light guide plate, and a third light guide plate. The first light guide plate has a first light-incident surface and a first surface. The first light-incident surface is disposed opposite to the first light-emitting element. The first surface is connected to the first light-incident surface and is located on the side of the first light guide plate facing away from the inverse prism lens. The first surface is formed with a first concave eye structure, and the first concave eye structure has two opposite first eye corners. The connection line between the two first eye corners forms a first major axis, and the first major axis extends along a reference direction. The second light guide plate has a second light-incident surface and a second surface. The second light-incident surface is disposed opposite to the second light-emitting element. The second surface is connected to the second light-incident surface and is located on the side of the second light guide plate facing away from the inverse prism lens. The second surface is formed with a second concave eye structure, and the second concave eye structure has two opposite second eye corners. The connection line between the two second eye corners forms a second major axis. The third light guide plate has a third light-incident surface and a third surface. The third light-incident surface is disposed opposite to the third light-emitting element. The third surface is connected to the third light-incident surface and is located on the side of the third light guide plate facing away from the inverse prism lens. The third surface is formed with a third concave eye structure, and the third concave eye structure has two opposite third eye corners. The connection line between the two third eye corners forms a third major axis. The projections of the second major axis and the third major axis on the first surface are inclined toward opposite sides of the reference direction respectively.

[0006] In an embodiment of the present invention, for example, the above-mentioned first light guide plate further has a side surface and a first light-emitting surface. The first light-emitting surface is connected to the first light-incident surface and is opposite to the first surface. The side surface is connected between the first light-incident surface, the first light-emitting surface, and the first surface. The included angle between the first major axis and the normal of the side surface is A1, where 80° ≤ A1 ≤ 100°. The included angle between the second major axis and the normal of the side surface is A2, where 100° < A2 < 180°. The included angle between the third major axis and the normal of the side surface is A3, where 0° < A3 < 80°.

[0007] In an embodiment of the present invention, where 130 < A2 < 140 and 40 < A3 < 50.

[0008] In an embodiment of the present invention, the above-mentioned first light guide plate can be closer to the reverse prism lens than the second light guide plate and the third light guide plate.

[0009] In an embodiment of the present invention, the number of the above-mentioned first concave eye structures, second concave eye structures, and third concave eye structures can be multiple. In the normal direction of the first light-incident surface, the first concave eye structures are arranged at equal intervals or unequal intervals. In the normal direction of the second light-incident surface, the second concave eye structures are arranged at equal intervals or unequal intervals. In the normal direction of the third light-incident surface, the third concave eye structures are arranged at equal intervals or unequal intervals.

[0010] In an embodiment of the present invention, for example, the above-mentioned first concave eye structures are arranged at unequal intervals, and the distance between some of the first concave eye structures closer to the first light-incident surface is greater than the distance between some of the first concave eye structures farther from the first light-incident surface. The second concave eye structures are arranged at unequal intervals, and the distance between some of the second concave eye structures closer to the second light-incident surface is greater than the distance between some of the second concave eye structures farther from the second light-incident surface. The third concave eye structures can be arranged at unequal intervals, and the distance between some of the third concave eye structures closer to the third light-incident surface is greater than the distance between some of the third concave eye structures farther from the third light-incident surface.

[0011] In an embodiment of the present invention, the above-mentioned first light guide plate may further include a plurality of first light-scattering microstructures. The first surface has a first near-light region and a first far-light region, and the first near-light region is closer to the first light-incident surface than the first far-light region. The first concave eye structures are formed in the first far-light region, and the first light-scattering microstructures are located in the first near-light region. The second light guide plate may further include a plurality of second light-scattering microstructures. The second surface has a second near-light region and a second far-light region, and the second near-light region is closer to the second light-incident surface than the second far-light region. The second concave eye structures are formed in the second far-light region, and the second light-scattering microstructures are located in the second near-light region. The third light guide plate, for example, further includes a plurality of third light-scattering microstructures. The third surface has a third near-light region and a third far-light region, and the third near-light region is closer to the third light-incident surface than the third far-light region. The third concave eye structures are formed in the third far-light region, and the third light-scattering microstructures are located in the third near-light region.

[0012] In an embodiment of the present invention, the above-mentioned backlight module may further include a fourth light-emitting element, a fifth light-emitting element, and a sixth light-emitting element. The fourth light-emitting element and the first light-emitting element are disposed on opposite sides of the first light guide plate. The fifth light-emitting element and the second light-emitting element are disposed on opposite sides of the second light guide plate. The sixth light-emitting element and the third light-emitting element are disposed on opposite sides of the third light guide plate.

[0013] In an embodiment of the present invention, the above-mentioned backlight module further includes, for example, a reflective sheet, and the reflective sheet is disposed on a side of the light guide assembly facing away from the reverse prism sheet.

[0014] The backlight module of the present invention employs a first light guide plate, a second light guide plate, and a third light guide plate. Specifically, the first light guide plate, the second light guide plate, and the third light guide plate have different light-emitting angles, and by activating any two of the first light-emitting element, the second light-emitting element, and the third light-emitting element, the light-emitting angles of any two of the first light guide plate, the second light guide plate, and the third light guide plate can be superimposed on each other. Therefore, the backlight module of the present invention can provide a multi-view switching function without reducing the brightness. In addition, since the backlight module of the present invention also employs a reverse prism sheet to narrow the light-emitting angle of the backlight module, the backlight module of the present invention also has the advantage of a small light-emitting angle.

[0015] To make the above and other objects, features, and advantages of the present invention more obvious and understandable, specific embodiments are hereinafter given in conjunction with the accompanying drawings and are described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of a backlight module according to an embodiment of the present invention.

[0017] Figure 2 is Figure 1 a bottom view of the first light guide plate of

[0018] Figure 3 is Figure 2 an enlarged schematic diagram of the first concave eye structure of

[0019] Figure 4 is Figure 1 a bottom view of the second light guide plate of

[0020] Figure 5 is Figure 4 an enlarged schematic diagram of the second concave eye structure of

[0021] Figure 6 is Figure 1 a bottom view of the third light guide plate of

[0022] Figure 7 is Figure 6 an enlarged schematic diagram of the third concave eye structure of

[0023] Figure 8 It is a schematic diagram of the first light guide plate of the backlight module according to another embodiment of the present invention.

[0024] Figure 9 is Figure 8 a schematic diagram of the second light guide plate of the backlight module of

[0025] Figure 10 is Figure 8 a schematic diagram of the third light guide plate of the backlight module of

[0026] Figure 11 It is a schematic diagram of the backlight module according to another embodiment of the present invention.

[0027] Among them, reference numerals:

[0028] 100, 100a, 100b: Backlight module

[0029] 110: First light-emitting element

[0030] 120: Second light-emitting element

[0031] 130: Third light-emitting element

[0032] 140: Inverse prism lens

[0033] 150, 150a: Light guide assembly

[0034] 151, 151a: First light guide plate

[0035] 152, 152a: Second light guide plate

[0036] 153, 153a: Third light guide plate

[0037] 160: Reflective sheet

[0038] 170: Fourth light-emitting element

[0039] 180: Fifth light-emitting element

[0040] 190: Sixth light-emitting element

[0041] 1510: First concave eye structure

[0042] 1511: First eye corner

[0043] 1520: Second concave eye structure

[0044] 1521: Second eye corner

[0045] 1530: Third concave eye structure

[0046] 1531: Third eye corner

[0047] A1, A2, A3: Included angles

[0048] B: Dorsal hillock

[0049] D: Reference direction

[0050] ES1: First light-emitting surface

[0051] ES2: Second light-emitting surface

[0052] ES3: Third light-emitting surface

[0053] F: Front hillock

[0054] IS1: First light-incident surface

[0055] IS2: Second light-incident surface

[0056] IS3: Third light-incident surface

[0057] L1: First major axis

[0058] L2: Second major axis

[0059] L3: Third major axis

[0060] MS1: First astigmatic microstructure

[0061] MS2: Second astigmatic microstructure

[0062] MS3: Third astigmatic microstructure

[0063] N, N1, N2, N3: Normal direction

[0064] S: Side surface

[0065] S1, S1a: First surface

[0066] S2, S2a: Second surface

[0067] S3, S3a: Third surface

[0068] SS1: First slope surface

[0069] SS2: Second slope surface

[0070] Z1: First low-beam region

[0071] Z2: First high-beam region

[0072] Z3: Second low-beam region

[0073] Z4: Second high-beam region

[0074] Z5: Third low-beam region

[0075] Z6: Third high-beam region Detailed implementation manners

[0076] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but it is not intended to limit the present invention.

[0077] Figure 1 It is a schematic diagram of a backlight module according to an embodiment of the present invention. Figure 2 is Figure 1 a bottom view schematic diagram of the first light guide plate of Figure 3 is Figure 2 an enlarged schematic diagram of the first concave eye structure of Figure 4 is Figure 1 a bottom view schematic diagram of the second light guide plate of Figure 5 is Figure 4 an enlarged schematic diagram of the second concave eye structure of Figure 6 is Figure 1 a bottom view schematic diagram of the third light guide plate of Figure 7 is Figure 6 an enlarged schematic diagram of the third concave eye structure of

[0078] Please first refer to Figure 1 , the backlight module 100 includes a first light-emitting element 110, a second light-emitting element 120, a third light-emitting element 130, a reverse prism lens 140, and a light guide assembly 150. The light guide assembly 150 is disposed opposite to the reverse prism lens 140. The light guide assembly 150 includes a first light guide plate 151, a second light guide plate 152, and a third light guide plate 153. The first light guide plate 151 has a first light-incident surface IS1 and a first surface S1. The first light-incident surface IS1 is disposed opposite to the first light-emitting element 110. The first surface S1 is connected to the first light-incident surface IS1 and is located on the side of the first light guide plate 151 facing away from the reverse prism lens 140. Please refer to Figure 2 and Figure 3 , at least one first concave eye structure 1510 is formed on the first surface S1 (also shown in Figure 1 ), and in this embodiment, a plurality of first concave eye structures 1510 are exemplified. Each first concave eye structure 1510 has two opposite first eye corners 1511. The connection line between the two first eye corners 1511 forms a first major axis L1, and the first major axis L1 extends along the reference direction D. Please refer to Figure 1 again, the second light guide plate 152 has a second light-incident surface IS2 and a second surface S2. The second light-incident surface IS2 is disposed opposite to the second light-emitting element 120. The second surface S2 is connected to the second light-incident surface IS2 and is located on the side of the second light guide plate 152 facing away from the reverse prism lens 140. Please refer to Figure 4 and Figure 5 , at least one second concave eye structure 1520 is formed on the second surface S2 (also shown in Figure 1), and in this embodiment, a plurality of second concave eye structures 1520 are exemplified. Each second concave eye structure 1520 has two opposite second eye corners 1521. The line connecting the two second eye corners 1521 forms a second major axis L2. Please refer back to Figure 1 , the third light guide plate 153 has a third light incident surface IS3 and a third surface S3. The third light incident surface IS3 is disposed opposite to the third light emitting element 130. The third surface S3 is connected to the third light incident surface IS3 and is located on the side of the third light guide plate 153 facing away from the reverse prism lens 140. Please refer to Figure 6 and Figure 7 , at least one third concave eye structure 1530 is formed on the third surface S3 (also shown in Figure 1 ), and in this embodiment, a plurality of third concave eye structures 1530 are exemplified. The third concave eye structure 1530 has two opposite third eye corners 1531. The line connecting the two third eye corners 1531 forms a third major axis L3. As shown in Figure 5 and Figure 7 , the projections of the second major axis L2 and the third major axis L3 on the first surface S1 are inclined toward opposite sides of the reference direction D.

[0079] Please refer back to Figure 1 , the first light emitting element 110, the second light emitting element 120, and the third light emitting element 130 may include light emitting diodes. However, in other embodiments, the first light emitting element 110, the second light emitting element 120, and the third light emitting element 130 may also be other types of light emitting elements. In addition, in one embodiment, the first light emitting element 110, the second light emitting element 120, and the third light emitting element 130 may be light emitting wafers cut from a single wafer and not encapsulated, such as light emitting diode wafers. For example, the light emitting diode wafers may be grain-level nitride light emitting diode wafers that emit blue light at the main wavelength, but the present invention is not limited thereto. In addition, the first light emitting element 110, the second light emitting element 120, and the third light emitting element 130 of this embodiment may be arranged in an array respectively, and the present invention does not limit the number of the first light emitting element 110, the second light emitting element 120, and the third light emitting element 130.

[0080] In the light guide assembly 150 of the present embodiment, the first light guide plate 151, the second light guide plate 152, and the third light guide plate 153 can respectively provide different light-emitting angles, wherein the light-emitting angle of the first light guide plate 151 can be closer to the forward light emission than those of the second light guide plate 152 and the third light guide plate 153. For example, the first light guide plate 151 may further have a first light-emitting surface ES1; the first light-emitting surface ES1 is connected to the first light-incident surface IS1 and is opposite to the first surface S1. In one embodiment, the half-value angle of the light beam generated by the first light-emitting element 110 exiting from the first light-emitting surface ES1 of the first light guide plate 151 may be approximately between -22° and 22°, and the central viewing angle is, for example, approximately 0°. Similarly, the half-value angle of the light beam generated by the second light-emitting element 120 exiting from the second light-emitting surface ES2 of the second light guide plate 152 may be approximately between -30° and 14°, and the central viewing angle may be approximately -8°; the half-value angle of the light beam generated by the third light-emitting element 130 exiting from the third light-emitting surface ES3 of the third light guide plate 153 may be approximately between -14° and 30°, and the central viewing angle may be approximately 8°. In this way, when any one of the first light-emitting element 110, the second light-emitting element 120, and the third light-emitting element 130 is activated, the backlight module 100 can respectively provide three different light-emitting angles. More specifically, if the first light-emitting element 110 and the second light-emitting element 120 are activated simultaneously, the backlight module 100 can provide the light-emitting angle obtained by superimposing the first light guide plate 151 and the second light guide plate 152; similarly, if the first light-emitting element 110 and the third light-emitting element 130 are activated simultaneously, the backlight module 100 can provide the light-emitting angle obtained by superimposing the first light guide plate 151 and the third light guide plate 153. Incidentally, in the present embodiment, the first light guide plate 151 can be closer to the inverse prism lens 140 than the second light guide plate 152 and the third light guide plate 153. In this way, when the first light-emitting element 110 is activated alone to use the light-emitting viewing angle of the first light guide plate 151, the second light guide plate 152 and the third light guide plate 153 will not interfere with the path of the light beam exiting from the first light-emitting surface ES1 of the first light guide plate 151.

[0081] The first light guide plate 151, the second light guide plate 152, and the third light guide plate 153 respectively provide different light-emitting angles with the first concave-eye structure 1510, the second concave-eye structure 1520, and the third concave-eye structure 1530. Since the characteristics of the first concave-eye structure 1510, the second concave-eye structure 1520, and the third concave-eye structure 1530 are similar to each other, only the characteristics of the first concave-eye structure 1510 will be described below, and the characteristics of the second concave-eye structure 1520 and the third concave-eye structure 1530 will be omitted here. Please refer to Figure 3, the first concave eye structure 1510 is recessed in the first surface S1, for example, and the shape of the first concave eye structure 1510 can be semi-olive spherical. On the other hand, a plurality of front mounds F and a plurality of back mounds B can also be formed on the first surface S1 of the first light guide plate 151, wherein each front mound F and each back mound B can protrude from the first surface S1, and the front mound F can be closer to the first light incident surface IS1 than the back mound B. In addition, each first concave eye structure 1510 can be located between each front mound F and each back mound B. Specifically, the first eye corner 1511 is close to the junction of the front mound F and the back mound B, for example. Incidentally, each first concave eye structure 1510 can also have a first slope surface SS1 and a second slope surface SS2, wherein the first slope surface SS1 is connected to the front mound F, and the second slope surface SS2 is connected to the back mound B. In this embodiment, the first slope surface SS1 and the second slope surface SS2 can be arc surfaces, and the areas of the first slope surface SS1 and the second wave surface SS2 can be different from each other, but the present invention does not limit these details much.

[0082] Please refer to again Figure 1 and Figure 2 , in this embodiment, the first light guide plate 151 also has a side surface S, for example. The side surface S is connected between the first light incident surface IS1, the first light exit surface ES1 and the first surface S1. As Figure 3 shown, the included angle between the first major axis L1 and the normal N of the side surface S is A1, and in one embodiment, 80° ≤ A1 ≤ 100°. Please refer to together Figure 4 and Figure 5 , the included angle between the second major axis L2 and the normal N is A2, and in one embodiment, 100° < A2 < 180°. Please refer to together Figure 6 and Figure 7 , the included angle between the third major axis L3 and the normal N is A3 and in one embodiment, 0° < A3 < 80°. Further, please refer to together Figure 5 and Figure 7 , in one embodiment, 130 < A2 < 140, and 40 < A3 < 50; for example, in another embodiment, A2 can be about 135°, and A3 can be about 45°, but the present invention does not limit these details much.

[0083] Please refer to again Figure 2, on the normal N1 of the first light incident surface IS1, the first concave eye structures 1510 are arranged at unequal intervals. For example, in this embodiment, the spacing between some of the first concave eye structures 1510 close to the first light incident surface IS1 is greater than the spacing between some of the first concave eye structures 1510 far from the first light incident surface IS1. Specifically, since the amount of light beams passing through the part of the first light guide plate 151 close to the first light incident surface IS1 is larger, the first concave eye structures 1510 can be arranged more dispersedly at the part of the first surface S1 close to the first light emitting element 110. On the contrary, because the amount of light beams passing through the part of the first light guide plate 151 far from the first light incident surface IS1 is smaller, the first concave eye structures 1510 can be arranged more concentratedly at the part of the first surface S1 far from the first light emitting element 110. However, in one embodiment, the first concave eye structures 1510 can be arranged at equal intervals on the normal N1 of the first light incident surface IS1.

[0084] On the other hand, as Figure 4 shown, on the normal N2 of the second light incident surface IS2, the second concave eye structures 1520 are arranged at unequal intervals; further, the spacing between some of the second concave eye structures 1520 close to the second light incident surface IS2 is greater than the spacing between some of the second concave eye structures 1520 far from the second light incident surface IS2. In this way, the light emission brightness of the second light emitting surface ES2 of the second light guide plate 152 can be more uniform. However, in one embodiment, the second concave eye structures 1520 can be arranged at equal intervals on the normal N2 of the second light incident surface IS2.

[0085] Similarly, as Figure 6 shown, on the normal N3 of the third light incident surface IS3, the third concave eye structures 1530 are arranged at unequal intervals; for example, the spacing between some of the third concave eye structures 1530 close to the third light incident surface IS3 is greater than the spacing between some of the third concave eye structures 1530 far from the third light incident surface IS3, so that the light emission brightness of the third light emitting surface ES3 of the third light guide plate 153 can be more uniform. It can be understood that in other embodiments, the third concave eye structures 1530 can be arranged at equal intervals on the normal N3 of the third light incident surface IS3.

[0086] Please refer to Figure 1 again. The inverse prism lens 140 can further reduce the light emission angle of view to further improve the anti-peeping effect. Specifically, the inverse prism lens 140 can include a plate body and a plurality of prism columns, wherein the aforementioned prism columns are, for example, arranged side by side on the aforementioned plate body and protrude towards the first light guide plate 151.

[0087] Compared with the prior art, the backlight module 100 of this embodiment adopts a first light guide plate 151, a second light guide plate 152, and a third light guide plate 153. Specifically, the first light guide plate 151, the second light guide plate 152, and the third light guide plate 153 have different light-emitting angles, and by activating any two of the first light-emitting element 110, the second light-emitting element 120, and the third light-emitting element 130, the light-emitting angles of any two of the first light guide plate 151, the second light guide plate 152, and the third light guide plate 153 can be superimposed on each other. Therefore, the backlight module 100 can provide the function of multi-view switching without reducing the brightness. In addition, since the backlight module 100 also adopts an inverse prism lens 140 to narrow the light-emitting angle of the backlight module 100, the backlight module 100 also has the advantage of a small light-emitting angle.

[0088] Incidentally, the backlight module 100 may further include, for example, a reflective sheet 160. The reflective sheet 160 is disposed on the side of the light guide assembly 150 facing away from the inverse prism lens 140 to increase the light utilization rate. In this embodiment, the material of the reflective sheet 160 may include silver, but the present invention is not limited thereto.

[0089] Figure 8 It is a schematic diagram of the first light guide plate of the backlight module according to another embodiment of the present invention. Figure 9 is Figure 8 a schematic diagram of the second light guide plate of the backlight module. Figure 10 is Figure 8 a schematic diagram of the third light guide plate of the backlight module. The structure and advantages of the backlight module 100a of this embodiment are similar to Figure 1 the embodiment of, and only the differences will be described below. Please first refer to Figure 8 , in the light guide assembly 150a of this embodiment, the first light guide plate 151a may further include a plurality of first light-scattering microstructures MS1. The first surface S1a has a first near-light region Z1 and a first far-light region Z2, and the first near-light region Z1 is closer to the first light-incident surface IS1 than the first far-light region Z2. The first concave-eye structure 1510 is formed in the first far-light region Z2, and the first light-scattering microstructures MS1 are located in the first near-light region Z1 to make the light-emitting brightness of the first light-emitting surface ES1 more uniform. Incidentally, the first light-scattering microstructures MS1 may protrude from or be recessed from the first surface S1a, and the present invention does not limit this further. Similarly, please refer to Figure 9, in this embodiment, the second light guide plate 152a may further include a plurality of second light-scattering microstructures MS2. The second surface S2a has a second near-light region Z3 and a second far-light region Z4, and the second near-light region Z3 is closer to the second light incident surface IS2 than the second far-light region Z4. The second concave-eye structure 1520 is formed in the second far-light region Z4, and the second light-scattering microstructures MS2 are located in the second near-light region Z3, making the light emission brightness of the second light exit surface ES2 more uniform. It can be understood that since the characteristics of the second light-scattering microstructures MS2 are similar to those of the first light-scattering microstructures MS1, the related description is omitted here. Please refer to Figure 10 , for example, the third light guide plate 153a may further include a plurality of third light-scattering microstructures MS3. The third surface S3 has a third near-light region Z5 and a third far-light region Z6, and the third near-light region Z5 is closer to the third light incident surface IS3 than the third far-light region Z6. The third concave-eye structure 1530 is formed in the third far-light region Z6, and the third light-scattering microstructures MS3 are located in the third near-light region Z5, making the light emission brightness of the third light exit surface ES3 more uniform. Similarly, the detailed characteristics of the third light-scattering microstructures MS3 are omitted here.

[0090] Figure 11 is a schematic diagram of a backlight module according to another embodiment of the present invention. The structure and advantages of the backlight module 100b in this embodiment are similar to those of Figure 1 the embodiment, and only the differences are described below. Please refer to Figure 11 , the backlight module 100b may further include a fourth light-emitting element 170, a fifth light-emitting element 180, and a sixth light-emitting element 190. The fourth light-emitting element 170 and the first light-emitting element 110 are disposed on opposite sides of the first light guide plate 151. The fifth light-emitting element 180 and the second light-emitting element 120 are disposed on opposite sides of the second light guide plate 152. The sixth light-emitting element 190 and the third light-emitting element 130 are disposed on opposite sides of the third light guide plate 153. In this way, the light emission brightness of the first light guide plate 151, the second light guide plate 152, and the third light guide plate 153 can be further increased. It can be understood that the characteristics of the fourth light-emitting element 170, the fifth light-emitting element 180, and the sixth light-emitting element 190 are similar to those of the first light-emitting element 110, the second light-emitting element 120, and the third light-emitting element 130, so the related description is omitted here.

[0091] In summary, the backlight module of the present invention adopts a first light guide plate, a second light guide plate and a third light guide plate. Specifically, the first light guide plate, the second light guide plate and the third light guide plate have different light-emitting angles, and by activating any two of the first light-emitting element, the second light-emitting element and the third light-emitting element, the light-emitting angles of any two of the first light guide plate, the second light guide plate and the third light guide plate can be superimposed on each other. Therefore, the backlight module of the present invention can provide the function of multi-view switching without reducing the brightness. In addition, because the backlight module of the present invention also adopts an inverse prism lens to narrow the light-emitting angle of the backlight module, the backlight module of the present invention also has the advantage of a small light-emitting angle.

[0092] Although the present invention has been disclosed above by way of examples, it is not intended to limit the present invention. Those of ordinary skill in the technical field to which the present invention pertains may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the appended patent application.

Claims

1. A backlight module, characterized in that, Comprising: a first light-emitting element, a second light-emitting element, and a third light-emitting element; an inverse prism lens; and a light guide assembly disposed opposite to the inverse prism lens, the light guide assembly comprising: a first light guide plate having a first light-incident surface and a first surface, the first light-incident surface being disposed opposite to the first light-emitting element, the first surface connecting the first light-incident surface and being located on a side of the first light guide plate facing away from the inverse prism lens, wherein a first concave-eye structure is formed on the first surface, and the first concave-eye structure has two opposite first eye corners, a connection line between the two first eye corners forms a first major axis, and the first major axis extends along a reference direction; a second light guide plate having a second light-incident surface and a second surface, the second light-incident surface being disposed opposite to the second light-emitting element, the second surface connecting the second light-incident surface and being located on a side of the second light guide plate facing away from the inverse prism lens, wherein a second concave-eye structure is formed on the second surface, and the second concave-eye structure has two opposite second eye corners, a connection line between the two second eye corners forms a second major axis; and a third light guide plate having a third light-incident surface and a third surface, the third light-incident surface being disposed opposite to the third light-emitting element, the third surface connecting the third light-incident surface and being located on a side of the third light guide plate facing away from the inverse prism lens, wherein a third concave-eye structure is formed on the third surface, and the third concave-eye structure has two opposite third eye corners, a connection line between the two third eye corners forms a third major axis; wherein the projections of the second major axis and the third major axis on the first surface are inclined toward opposite sides of the reference direction; the first light guide plate further has a side surface and a first light-emitting surface, the first light-emitting surface connecting the first light-incident surface and being opposite to the first surface, the side surface connecting between the first light-incident surface, the first light-emitting surface, and the first surface, and there is an included angle between the reference direction and the normal direction of the side surface; the first light guide plate, the second light guide plate, and the third light guide plate respectively provide different light-emitting angles with the first concave-eye structure, the second concave-eye structure, and the third concave-eye structure, and the light-emitting angle of the first light guide plate is closer to the forward light-emitting direction than that of the second light guide plate and the third light guide plate.

2. The backlight module according to claim 1, characterized in that, The included angle between the first major axis and the normal direction of the side surface is A1, 80° ≤ A1 ≤ 100°; The included angle between the second major axis and the normal direction of the side surface is A2, 100° < A2 < 180°; The included angle between the third major axis and the normal direction of the side surface is A3, 0° < A3 < 80°.

3. The backlight module according to claim 2, characterized in that: 130° < A2 < 140°, 40° < A3 < 50°.

4. The backlight module according to claim 1, wherein The first light guide plate is closer to the inverse prism lens than the second light guide plate and the third light guide plate.

5. The backlight module according to claim 1, characterized in that, The number of the first concave-eye structure, the second concave-eye structure, and the third concave-eye structure is multiple; In the normal direction of the first light-incident surface, the first concave-eye structures are arranged at equal intervals or unequal intervals; In the normal direction of the second light-incident surface, the second concave-eye structures are arranged at equal intervals or unequal intervals; In the normal direction of the third light-incident surface, the third concave-eye structures are arranged at equal intervals or unequal intervals.

6. The backlight module according to claim 5, wherein: The first concave eye structures are arranged at unequal intervals, and the distance between the first concave eye structures in the part closer to the first light incident surface is greater than the distance between the first concave eye structures in the part farther from the first light incident surface; The second concave eye structures are arranged at unequal intervals, and the distance between the second concave eye structures in the part closer to the second light incident surface is greater than the distance between the second concave eye structures in the part farther from the second light incident surface; The third concave eye structures are arranged at unequal intervals, and the distance between the third concave eye structures in the part closer to the third light incident surface is greater than the distance between the third concave eye structures in the part farther from the third light incident surface.

7. The backlight module according to claim 1, wherein: The first light guide plate further includes a plurality of first light diffusing microstructures. The first surface has a first near-light region and a first far-light region. The first near-light region is closer to the first light incident surface than the first far-light region. The first concave eye structures are formed in the first far-light region, and the first light diffusing microstructures are located in the first near-light region; The second light guide plate further includes a plurality of second light diffusing microstructures. The second surface has a second near-light region and a second far-light region. The second near-light region is closer to the second light incident surface than the second far-light region. The second concave eye structures are formed in the second far-light region, and the second light diffusing microstructures are located in the second near-light region; The third light guide plate further includes a plurality of third light diffusing microstructures. The third surface has a third near-light region and a third far-light region. The third near-light region is closer to the third light incident surface than the third far-light region. The third concave eye structures are formed in the third far-light region, and the third light diffusing microstructures are located in the third near-light region.

8. The backlight module according to claim 1, characterized in that, It further includes a fourth light-emitting element, a fifth light-emitting element, and a sixth light-emitting element, wherein: The fourth light-emitting element and the first light-emitting element are arranged on opposite sides of the first light guide plate; The fifth light-emitting element and the second light-emitting element are arranged on opposite sides of the second light guide plate; The sixth light-emitting element and the third light-emitting element are arranged on opposite sides of the third light guide plate.

9. The backlight module according to claim 1, wherein It further includes a reflective sheet disposed on a side of the light guide assembly facing away from the reverse prism lens.

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