TWI894574B - Optical film and display device - Google Patents

Abstract

An optical film includes a grid layer. The grid layer has a first surface, a second surface, a plurality of shade portions and a plurality of translucent portions. The first surface is opposite to the second surface. The shade portions and the translucent portions are located between the first surface and the second surface and are disposed alternately. The shade portions have the following characteristics. A third surface is coplanar with the first surface. A fourth surface and a fifth surface is connected to two opposite sides of the third surface. An angle of an included angle between the fourth surface and the third surface is A1, and an angle of an included angle between the fifth surface and the third surface is A2. A sixth surface is connected to the fourth surface and the second surface. The seventh surface is connected to the fifth surface and the second surface. An angle of an included angle between the sixth surface and the second surface is A3, and an angle of an included angle between the seventh surface and the second surface is A4. A1 and A2 are between 85~90°, A3 and A4 are between 0~85°, A2≠A4, and A1≠A3. A display device is also provided.

Description

Optical film and display device

The present invention relates to an optical element, in particular an optical film, and a display device having the optical film.

Depending on the type of light source, known display devices include liquid crystal displays (LCDs), light-emitting diode (LED) displays, and organic light-emitting diode (OLED) displays. For example, the main components of an LCD include a backlight module, a display panel, and a frame. The backlight module can be further divided into edge-lit backlight modules and direct-lit backlight modules. Generally speaking, edge-lit backlight modules are less expensive, while direct-lit backlight modules are more suitable for achieving local dimming. Furthermore, each of these display types is typically equipped with an optical film to adjust the imaging effect according to different requirements.

This "Prior Art" section is intended solely to facilitate understanding of the present invention. Therefore, the information disclosed in this section may contain information that does not constitute general knowledge within the art. Furthermore, the information disclosed in this section does not represent that the information or one or more embodiments of the present invention address the problem or problems to be solved, nor does it represent that the information or information was known or understood by a person of ordinary skill in the art prior to the filing of this application.

The present invention provides an optical film that can reduce the light output angle, thereby reducing stray light caused by excessively large light output angles.

The present invention provides a display device to improve image quality.

Other purposes and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

To achieve one, part, or all of the above-mentioned purposes or other purposes, the optical film provided by the present invention includes a grid layer. The grid layer has a first surface, a second surface, a plurality of light-shielding portions, and a plurality of light-transmitting portions. The first surface is opposite to the second surface and is parallel to each other. The light-shielding portions and the light-transmitting portions are located between the first surface and the second surface, and the light-shielding portions and the light-transmitting portions are alternately arranged along the first surface. Each light-shielding portion has a third surface, a fourth surface, a fifth surface, a sixth surface, and a seventh surface. The third surface is coplanar with the first surface. The fourth surface and the fifth surface are respectively connected to opposite sides of the third surface. The first angle between the fourth surface and the third surface is A1, and the second angle between the fifth surface and the third surface is A2. The sixth surface connects the fourth surface and the second surface. The seventh surface connects the fifth surface and the second surface. The third angle between the sixth surface and the second surface is A3, and the fourth angle between the seventh surface and the second surface is A4. Among them, 85°<A1≦90°, 85°<A2≦90°, 0°<A3<85°, 0°<A4<85°, A2≠A4, and A1≠A3.

In one embodiment of the present invention, each of the aforementioned light-shielding portions may further have a first corner and a second corner. Each fourth surface has a first edge and a second edge opposite each other. The first edge is adjacent to the third surface. The second edge is connected to the sixth surface, and the first corner is located between the fourth and sixth surfaces. Each fifth surface has a third edge and a fourth edge opposite each other. The third edge is adjacent to the third surface. The fourth edge is connected to the seventh surface, and the second corner is located between the fifth and seventh surfaces. In a first direction from the first surface to the second surface, each first corner and each second corner are farther from the first surface and closer to the second surface.

In one embodiment of the present invention, the aforementioned light shielding portions are disposed on the first surface at equal distances from each other.

In one embodiment of the present invention, in the direction in which the light-shielding portions and the light-transmitting portions are alternately arranged along the first surface, the distance between the third edge of the fifth surface of one light-shielding portion connected to the third surface and the third edge of the fifth surface of another adjacent light-shielding portion connected to the third surface may be between 30 μm and 200 μm.

In one embodiment of the present invention, the distance between the first surface and the second surface in a first direction from the first surface to the second surface may be between 30 μm and 200 μm.

In one embodiment of the present invention, the side of the sixth surface of each light-shielding portion connected to the second surface and the side of the seventh surface connected to the second surface are, for example, adjacent to each other or not adjacent to each other.

In one embodiment of the present invention, the cross-section of each of the light-shielding portions extending from the first surface to the second surface may be asymmetrical.

In one embodiment of the present invention, any two of the aforementioned light-shielding portions may have different shapes.

In one embodiment of the present invention, the optical film further includes a first light-transmitting plate disposed on a side of the second surface facing away from the light-shielding portion.

In one embodiment of the present invention, the first light-transmitting plate may have a first light-transmitting surface and a second light-transmitting surface. The first light-transmitting surface and the second light-transmitting surface are opposed to each other, and the first light-transmitting surface is disposed on a side of the second surface facing away from the light-shielding portion. The second light-transmitting surface may have a plurality of first microstructures.

In one embodiment of the present invention, the optical film may further include a plurality of first light scattering particles disposed within the first light-transmitting plate.

In one embodiment of the present invention, the optical film may further include a light-transmitting layer disposed between the second surface and the first light-transmitting plate.

In one embodiment of the present invention, the optical film further includes a second light-transmitting plate, which is disposed on the first surface.

In one embodiment of the present invention, the second light-transmitting plate may have a third light-transmitting surface and a fourth light-transmitting surface. The third light-transmitting surface and the fourth light-transmitting surface are opposed to each other, and the third light-transmitting surface is disposed on the first surface. The fourth light-transmitting surface has a plurality of second microstructures.

In one embodiment of the present invention, the optical film may further include a plurality of second light scattering particles disposed within the second light-transmitting plate.

In one embodiment of the present invention, the second light-transmitting plate includes, for example, a brightness enhancement film.

In one embodiment of the present invention, the absolute value of the refractive index difference between the light-shielding portion and the light-transmitting portion is, for example, greater than 0.005.

Effect: Excellent total reflection effect, increasing light brightness

To achieve one, some, or all of the above objectives, or other objectives, the present invention provides a display device comprising a light guide plate, a light source, a display panel, and an optical film. The light guide plate has a light incident surface and a light emitting surface, the light emitting surface being connected to the light receiving surface. The light source is disposed opposite the light incident surface. The display panel is disposed opposite the light emitting surface. The optical film is disposed between the light emitting surface and the display panel.

In one embodiment of the present invention, the first surface or the second surface may face the display panel.

The optical film of the present invention utilizes a grid layer comprising multiple light-blocking sections and multiple light-transmitting sections. Specifically, the light-blocking sections have two connected, mutually inclined surfaces (i.e., the fourth, fifth, sixth, and seventh surfaces) on opposite sides, while the light-transmitting section is located between adjacent light-blocking sections. This allows a light beam passing through the light-transmitting section to be incident on either the fourth or fifth surface, where it is then reflected and exits the grid layer. As a result, the light beam's angle of exit from the grid layer is smaller than its angle of entry into the grid layer. Therefore, the optical film of the present invention can reduce stray light caused by excessively large light output angles. Because the display device of the present invention utilizes the aforementioned optical film, it can improve stray light that occurs at wide viewing angles, thereby enhancing image quality.

In order to make the above and other purposes, features and advantages of the present invention more clearly understood, the following is a detailed description of the preferred embodiments with reference to the accompanying drawings.

10, 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10i, 10j, 10k, 10l: Optical Film

20, 20a: Display device

21: Light guide plate

22: Light Source

23: Display Panel

100, 100a, 100j, 100k, 100l: Grid layer

101, 101a: First side

102, 102a: Second side

103a: Third side

104a: Fourth side

110: First surface

120: Second surface

130, 130a, 130j, 130k: Light shielding parts

131: Third Surface

132: Fourth Surface

133: The Fifth Surface

134: Sixth Surface

135: Seventh Surface

136: The Eighth Surface

140, 140a, 140j, 140k, 140l: Translucent portion

200, 200c, 200d: First light-transmitting plate

210: First light-transmitting surface

211: Light-entering surface

212: Luminous side

213: Surface

220c, 220d: Second light-transmitting surface

221c, 221d: First microstructure

300: First light scattering particle

400: Translucent layer

500: Second light-transmitting plate

510: Third light-transmitting surface

520: Fourth light-transmitting surface

521: Second Microstructure

600: Second light scattering particles

1340, 1350: side

A1, A2, A3, A4: Angles

B1, B2: Beams

C1: First corner

C2: Second corner

CA, CA’: Cross-section

D: Direction

D1: First Direction

E1: First Edge

E2: Second Edge

E3: The Third Edge

E4: The Fourth Edge

EA, IA: Zhang Jiao

F1: Diffuse film

F2: Brightening film

H, P: distance

IA1: First Angle

IA2: Second angle

IA3: Third Angle

IA4: Fourth Angle

L1, L2, L3, L4: Length

S: Imaginary surface

T: Prism structure

Z1, Z2: Areas

Figure 1 is a schematic top view of an optical film according to one embodiment of the present invention.

Figure 2 is a schematic partial cross-sectional view of the optical film in Figure 1 along line A-A.

Figure 3 is a schematic top view of an optical film according to another embodiment of the present invention.

Figure 4 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 5 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 6 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 7 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 8 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 9 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 10 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 11 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 12 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 13 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 14 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention.

Figure 15 is a side view schematic diagram of a display device according to an embodiment of the present invention.

Figure 16 is a schematic cross-sectional view of the optical film and display panel in Figure 15.

Figure 17 is a schematic cross-sectional view of an optical film and display panel of a display device according to another embodiment of the present invention.

Figure 18 is a schematic diagram showing the light output pattern of a conventional display device and the light output pattern of a display device according to an embodiment of the present invention.

Figure 19 is a schematic diagram showing the light output field pattern of a conventional display device and the vertical viewing angle brightness distribution of a display device according to an embodiment of the present invention.

The aforementioned technical contents, features, and functions of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. Directional terms such as up, down, left, right, front, and back mentioned in the following embodiments are merely references to the directions in the accompanying drawings. Therefore, the directional terms used are for illustrative purposes only and are not intended to limit the present invention.

FIG1 is a schematic top view of an optical film according to an embodiment of the present invention. FIG2 is a schematic partial cross-sectional view of the optical film of FIG1 along the A-A section line. Referring to FIG1 and FIG2 , the optical film 10 includes a grid layer 100. The grid layer 100 has a first surface 110, a second surface 120 (shown in FIG2 ), a plurality of light-shielding portions 130, and a plurality of light-transmitting portions 140. The first surface 110 and the second surface 120 are opposite to and parallel to each other. The light-shielding portions 130 and the light-transmitting portions 140 are located between the first surface 110 and the second surface 120, and the light-shielding portions 130 and the light-transmitting portions 140 are alternately arranged along the first surface 110. Each light-shielding portion 130 has a third surface 131, a fourth surface 132, a fifth surface 133, a sixth surface 134, and a seventh surface 135. The third surface 131 is coplanar with the first surface 110. The fourth surface 132 and the fifth surface 133 connect to opposite sides of the third surface 131, respectively. A first angle IA1 between the fourth surface 132 and the third surface 131 is A1, and a second angle IA2 between the fifth surface 133 and the third surface 131 is A2. The sixth surface 134 connects the fourth surface 132 and the second surface 120. The seventh surface 135 connects the fifth surface 133 and the second surface 120. A third angle IA3 between the sixth surface 134 and the second surface 120 is A3, and a fourth angle IA4 between the seventh surface 135 and the second surface 120 is A4. The following conditions hold: 85° < A1 ≤ 90°, 85° < A2 ≤ 90°, 0° < A3 < 85°, 0° < A4 < 85°, A2 ≤ A4, and A1 ≤ A3. It should be further explained that, as can be seen from the top view of FIG1 , each light shielding portion 130 may extend from the first side 101 of the grid layer 100 to the second side 102 of the grid layer 100 opposite the first side 101 , but the present invention is not limited thereto.

The light-transmitting portion 140 allows light beams B1 and B2 (shown in FIG. 2 ) to pass through. In this embodiment, the material of the light-transmitting portion 140 may include UV-curable adhesive. Incidentally, the light-transmitting portion 140 is attached to and covers the outer surface of the light-shielding portion 130 . For example, in this embodiment, the light-transmitting portion 140 is attached to and covers the fourth surface 132 , fifth surface 133 , sixth surface 134 , and seventh surface 135 of the light-shielding portion 130 .

Continuing with Figure 2, the light shielding portion 130 can reflect the light beams B1 and B2 via the fourth surface 132 and the fifth surface 133. Specifically, the fourth surface 132 and the fifth surface 133 can be tilted toward each other relative to the first surface 110, thereby forming a first angle IA1 and a second angle IA2. Therefore, after being reflected by the fourth surface 132 and the fifth surface 133, the light beams B1 and B2 can exit the grid layer 100 at an angle smaller than the angle at which they were incident on the grid layer 100, thereby reducing the angle at which the light beams B1 and B2 exit the grid layer 100. For example, the light beams B1 and B2 enter the grid layer 100 at an angle IA and exit the grid layer 100 at an angle EA, where the angle EA is smaller than the angle IA. Furthermore, the light-shielding portions 130 and the light-transmitting portions 140 are arranged alternately along direction D, for example. This allows the light-shielding portions 130 to reduce the angle EA of the light beams B1 and B2 emerging from the grille layer 100 in direction D (also shown in FIG. 1 ). In one embodiment, the fourth surface 132 and the fifth surface 133 may be substantially perpendicular to the first surface 110. In other words, the first angle IA1 and the second angle IA2 may be approximately 90°, further reducing the angle EA of the light beams B1 and B2 emerging from the grille layer 100. Incidentally, the material of the light-shielding portions 130 may include UV-curable adhesive and carbon black. However, in one embodiment, the material of the light-shielding portions 130 may include a light-reflective material, thereby further increasing light utilization efficiency. However, the present invention does not impose any particular limitations on the material of the light-shielding portions 130.

In this embodiment, each light-shielding portion 130 may further have a first corner C1 and a second corner C2. Each fourth surface 132 has a first edge E1 and a second edge E2 opposite each other. The first edge E1 is adjacent to the third surface 131. The second edge E2 is connected to the sixth surface 134, and the first corner C1 is located between the fourth and sixth surfaces 132, 134. Each fifth surface 133 has a third edge E3 and a fourth edge E4 opposite each other. The third edge E3 is adjacent to the third surface 131. The fourth edge E4 is connected to the seventh surface 135, and the second corner C2 is located between the fifth and seventh surfaces 133, 135. In a first direction D1 pointing from the first surface 110 to the second surface 120, each first corner C1 and each second corner C2 are located farther from the first surface 110 and closer to the second surface 120, thereby further reducing the angle EA of the light beams B1 and B2 emitted from the grid layer 100. In other words, the length L1 of the third surface 131 may be greater than the length L2 of the sixth surface 134, and the length L3 of the fifth surface 133 may be greater than the length L4 of the seventh surface 135, so that the first corner C1 and the second corner C2 are farther from the first surface 110 and closer to the second surface 120. In this embodiment, the first corner C1 may be adjacent to the second edge E2 and the sixth surface 134, and the second corner C2 may be adjacent to the fourth edge E4 and the seventh surface 135. Incidentally, while the number of first corners C1 and second corners C2 is shown as one, and the shape of the light shielding portion 130 is shown as a pentagon, the present invention is not limited to this. For example, in one embodiment, the number of first corners C1 and second corners C2 may each be greater than one, and the shape of the light shielding portion 130 may not be limited to a pentagon.

In this embodiment, a side 1340 of the sixth surface 134 of each light-shielding portion 130 connected to the second surface 120 and a side 1350 of the seventh surface 135 connected to the second surface 120 are adjacent to each other. For example, the side 1340 of the sixth surface 134 and the side 1350 of the seventh surface 135 are adjacent to each other, forming a sharp angle. However, in one embodiment, the side 1340 of the sixth surface 134 and the side 1350 of the seventh surface 135 are adjacent to each other, forming a rounded angle. The present invention does not impose any restrictions on the shape of the connection between the sixth surface 134 and the seventh surface 135.

In this embodiment, along the direction D in which the light-shielding portions 130 and the light-transmitting portions 140 are alternately arranged along the first surface 110, the distance P between the third edge E3 of the fifth surface 133 of one light-shielding portion 130 and the third edge E3 of the fifth surface 133 of another adjacent light-shielding portion 130 may be between 30 μm and 200 μm. Specifically, the third edge E3 may, for example, be connected to the third surface 131 and coplanar with the first surface 110 and the third surface 131. In other words, the distance P may be the distance between the third edges E3 of two adjacent light-shielding portions 130 along the direction D. It should be noted that the light-shielding portions 130 of this embodiment may be equidistant from one another, meaning that the distance P between any two adjacent light-shielding portions 130 may be equal, but the present invention is not limited thereto. On the other hand, in this embodiment, the distance H between the first surface 110 and the second surface 120 in the first direction D1 may be between 30 μm and 200 μm. Similarly, the distance H between each light shielding portion 130 may be substantially equal. However, in other embodiments, the distance H between each light shielding portion 130 may vary slightly, and the present invention is not limited thereto.

Compared to conventional techniques, the optical film 10 of this embodiment utilizes a grid layer 100 comprising a plurality of light-blocking portions 130 and a plurality of light-transmitting portions 140. Specifically, the light-blocking portions 130 have two connected, mutually inclined surfaces (i.e., a fourth surface 132, a fifth surface 133, a sixth surface 134, and a seventh surface 135) on opposite sides thereof, while the light-transmitting portions 140 are located between adjacent light-blocking portions 130. Light beams B1 and B2, upon passing through the light-transmitting portions 140, can be incident on the fourth surface 132 or the fifth surface 133, where they are then reflected by the fourth surface 132 or the fifth surface 133 and emitted from the grid layer 100. Based on the above, the angle EA of the light beams B1 and B2 emerging from the grid layer 100 can be smaller than the angle IA of the light beams incident on the grid layer 100. Therefore, the optical film 10 of this embodiment can reduce stray light caused by excessively large light emission angles.

Incidentally, in one embodiment, the absolute value of the difference in refractive index between the light-shielding portion 130 and the light-transmitting portion 140 is, for example, greater than 0.005, to enhance the light reflectivity of the grille layer 100. Furthermore, the refractive index of the light-shielding portion 130 can be smaller than that of the light-transmitting portion 140, making it easier for the light beams B1 and B2 to undergo total internal reflection within the light-transmitting portion 140, thereby enhancing the brightness of the light beams B1 and B2 emerging from the grille layer 100. However, the refractive index of the light-shielding portion 130 can also be greater than that of the light-transmitting portion 140, and the present invention is not limited thereto.

Figure 3 is a schematic top view of an optical film according to another embodiment of the present invention. It will be appreciated that in other embodiments, the extension direction of the light shielding portion 130 may not be limited to that shown in Figures 1 and 2 . For example, referring to the optical film 10a in Figure 3 , a portion of the light shielding portion 130a extends from the first side 101a of the grid layer 100a to the second side 102a of the grid layer 100a opposite the first side 101a, while another portion of the light shielding portion 130a extends from the third side 103a of the grid layer 100a to the fourth side 104a of the grid layer 100a opposite the third side 103a. Furthermore, the first side 101a and the third side 103a are perpendicular to each other (e.g., substantially perpendicular to each other). In other words, the light-shielding portions 130a of this embodiment can be arranged in a checkerboard pattern on the grid layer 100a. Since the structure and advantages of the light-shielding portions 130a and light-transmitting portions 140a are substantially the same as those of the embodiment shown in FIG1 , their description will be omitted here.

FIG4 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. The structure and advantages of the optical film 10b of this embodiment are similar to those of the embodiment of FIG1 , and the differences are described below. Referring to FIG4 , the optical film 10b further includes, for example, a first light-transmitting plate 200, which is disposed on a side of the second surface 120 facing away from the light-shielding portion 130. For example, in this embodiment, the first light-transmitting plate 200 can be adhered to the second surface 120 of the grid layer 100. In this way, the light-shielding portion 130 and the light-transmitting portion 140 can be fixed to the first light-transmitting plate 200 to prevent the light-shielding portion 130 and the light-transmitting portion 140 from separating from each other, thereby enhancing the structural strength of the optical film 10b. In this embodiment, the material of the first light-transmitting plate 200 may include polyethylene terephthalate (PET), but other embodiments are not limited thereto.

Figure 5 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. Figure 6 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. The structures and advantages of optical films 10c and 10d are similar to those of the embodiment of Figure 4 . The differences are described below. Referring first to Figure 5 , the first light-transmitting plate 200c may have a first light-transmitting surface 210 and a second light-transmitting surface 220c. The first light-transmitting surface 210 and the second light-transmitting surface 220c are opposed to each other, and the first light-transmitting surface 210 is disposed on the side of the second surface 120 facing away from the light-shielding portion 130 (e.g., the second surface 120). The second light-transmitting surface 220c may have a plurality of first microstructures 221c to enhance the optical quality of the optical film 10c. For example, in this embodiment, the first microstructure 221c can be formed by roughening the second light-transmitting surface 220c to improve the light uniformity of the optical film 10c. However, in one embodiment, referring to Figure 6 , the first microstructure 221d can include a prism structure T. This can further reduce the angle at which the light beam incident from the first light-transmitting plate 200d enters the grid layer 100, thereby further reducing the angle at which the light beam exits the grid layer 100. It should be understood that the present invention does not impose any particular limitations on the specific shapes of the first microstructures 221c and 221d.

Figure 7 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. The structure and advantages of optical film 10e of this embodiment are similar to those of the embodiment shown in Figure 4 , with the differences described below. Referring first to Figure 7 , optical film 10e may further include a plurality of first light-scattering particles 300 disposed within first light-transmitting plate 200 . This further enhances the optical quality of optical film 10e . In this embodiment, the first light-scattering particles 300 may be made of a light-reflecting material and may be evenly distributed within first light-transmitting plate 200 .

Figure 8 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. The structure and advantages of the optical film 10f of this embodiment are similar to those of the embodiment shown in Figure 4 , with the differences described below. Referring to Figure 8 , the optical film 10f may further include a light-transmitting layer 400 disposed between the second surface 120 and the first light-transmitting plate 200. In other words, the light-transmitting layer 400 may be sandwiched between the second surface 120 and the first light-transmitting plate 200. In this embodiment, the material of the light-transmitting layer 400 may be the same as that of the light-transmitting portion 140, but this is not a limitation of the present invention.

Figure 9 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. The structure and advantages of the optical film 10g of this embodiment are similar to those of the embodiment shown in Figure 4 , with the differences described below. Referring to Figure 9 , the optical film 10g further includes a second light-transmitting plate 500 , disposed on the first surface 110 of the grid layer 100 . This allows the first and second light-transmitting plates 200 and 500 to further secure the light-shielding portion 130 and the light-transmitting portion 140 , further enhancing the structural strength of the optical film 10g . In one embodiment, the second light-transmitting plate 500 includes, for example, a dual brightness enhancement film (DBEF), which further enhances the light output brightness of the optical film 10g . In another embodiment, the second light-transmitting plate 500 may include a prism. The other features of the second light-transmitting plate 500 are the same as those of the first light-transmitting plate 200, so the relevant descriptions are omitted here.

Figure 10 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. The structure and advantages of the optical film 10h of this embodiment are similar to those of the embodiment shown in Figure 9 , with the differences described below. Referring to Figure 10 , the second light-transmitting plate 500 may have a third light-transmitting surface 510 and a fourth light-transmitting surface 520 . The third light-transmitting surface 510 and the fourth light-transmitting surface 520 are opposed to each other, and the third light-transmitting surface 510 is disposed on the first surface 110 . The fourth light-transmitting surface 520 may, for example, have a plurality of second microstructures 521 to enhance the optical quality of the optical film 10h . The features of the second microstructures 521 are similar to those of the first microstructures 221c in Figure 5 or the first microstructures 221d in Figure 6 , and therefore their description is omitted here.

Figure 11 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. The structure and advantages of optical film 10i of this embodiment are similar to those of the embodiment shown in Figure 9 , with the differences described below. Referring to Figure 11 , optical film 10i may also include a plurality of second light-scattering particles 600 disposed within the second light-transmitting plate 500 . This further enhances the optical quality of optical film 10i. The features of second light-scattering particles 600 are similar to those of first light-scattering particles 300 in Figure 7 , and therefore their description is omitted here.

FIG12 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. The structure and advantages of the optical film 10j of this embodiment are similar to those of the embodiment of FIG1 , with the differences described below. Referring to the grid layer 100j of FIG12 , a side 1340 of the sixth surface 134 of each light-shielding portion 130j connected to the second surface 120 and a side 1350 of the seventh surface 135 connected to the second surface 120 are, for example, non-adjacent to each other. In other words, the side 1340 of the sixth surface 134 and the side 1350 of the seventh surface 135 can be separated from each other. For example, the light-shielding portion 130j can further include an eighth surface 136, which can be connected between the side 1340 of the sixth surface 134 and the side 1350 of the seventh surface 135. Furthermore, the eighth surface 136 may be, for example, opposite the first surface 110 and the third surface 131, and may be coplanar with the second surface 120. However, the present invention does not impose any particular limitations on the specific structure of the separation between the sixth surface 134 and the seventh surface 135. Incidentally, the shape of the light-transmitting portion 140j can be modified based on the shape of the light-blocking portion 130j, such that the light-transmitting portion 140j fills the space between two adjacent light-blocking portions 130j and adheres to the outer surface of the light-blocking portion 130j. The present invention does not impose any particular limitations on the shape of the light-transmitting portion 140j.

FIG13 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. The structure and advantages of the optical film 10k of this embodiment are similar to those of the embodiment of FIG1 , and the differences are described below. Referring to the grid layer 100k of FIG13 , the cross-section CA of each light-shielding portion 130k extending from the first surface 110 to the second surface 120 may be an asymmetric shape. It should be noted that the opposite sides of the cross-section CA are connected to the first surface 110 and the second surface 120, respectively. In detail, in this embodiment, each light-shielding portion 130K may further have an imaginary surface S, the imaginary surface S being perpendicular to the first surface 110 and the second surface 120, and the imaginary surface S extending from the center of the third surface 131 to the second surface 120, and the direction facing the imaginary surface S and the extension direction of the light-shielding portion 130K are perpendicular to each other. The light-shielding portion 130k may be asymmetric with respect to the imaginary plane S. Furthermore, the fourth surface 132 and the fifth surface 133 may be asymmetric with respect to the imaginary plane S, and the sixth surface 134 and the seventh surface 135 may be asymmetric with respect to the imaginary plane S. However, the present invention does not impose any further restrictions on the shape of the light-shielding portion 130k. Similarly, in this embodiment, the shape of the light-transmitting portion 140k may be modified based on the shape of the light-shielding portion 130k, and the present invention does not impose any further restrictions on the shape of the light-transmitting portion 140k.

FIG14 is a partial cross-sectional schematic diagram of an optical film according to another embodiment of the present invention. The structure and advantages of the optical film 101 according to this embodiment are similar to those of the embodiment of FIG1 , and the differences are described below. In this embodiment, any two of all the shading portions may have different shapes. For example, referring to FIG14 , the grid layer 1001 may include shading portions 130 and 130k, and the shading portions 130 and 130k have different shapes. For example, the cross-section CA' of the shading portion 130 extending from the first surface 110 to the second surface 120 may be a symmetrical shape, and the cross-section CA of the shading portion 130k extending from the first surface 110 to the second surface 120 may be an asymmetrical shape. Since other features of the shading portions 130 and 130k have been described above, the relevant description is omitted here. It will be appreciated that in other embodiments, the grille layer 100l may include the light-shielding portion 130, the light-shielding portion 130j, the light-shielding portion 130k, or a combination thereof, and the shape of the light-shielding portion of this embodiment is not limited to the above examples. Similarly, the shape of the light-transmitting portion 140l of this embodiment may be modified based on the shape of the light-shielding portion 130, the light-shielding portion 130j, or the light-shielding portion 130k, and the present invention does not impose any further limitations on the shape of the light-transmitting portion 140l.

Figure 15 is a schematic side view of a display device according to an embodiment of the present invention. Referring to Figure 15 , the display device 20 includes a light guide plate 21, a light source 22, a display panel 23, and an optical film 10. The light guide plate 21 has a light incident surface 211 and a light emitting surface 212, with the light emitting surface 212 connected to the light incident surface 211. The light source 22 is disposed opposite the light incident surface 211. The display panel 23 is disposed opposite the light emitting surface 212. The optical film 10 is disposed between the light emitting surface 212 and the display panel 23.

The light guide plate 21, for example, has a light incident surface 211 and a light emitting surface 212, wherein the light incident surface 211 is connected to the light emitting surface 212 and is opposite to the light source 22. The material of the light guide plate 21 may include plastic, glass or other materials suitable for light penetration. For example, in the present embodiment, the material of the light guide plate 21 may include polymethyl methacrylate (PMMA); however, in other embodiments, the material of the light guide plate 21 may include cycloolefin polymer (COP) or polycarbonate (PC). In addition, the light guide plate 21 of the present embodiment may be manufactured by hot pressing or injection molding, but the present invention does not impose any restrictions on this. In one embodiment, the surface 213 of the light guide plate 21 opposite to the light emitting surface 212 may have a light-scattering structure, which can reflect more light beams to the light emitting surface 212, thereby improving light utilization efficiency.

The light source 22 of this embodiment may include a light-emitting diode (LED), wherein the number of the LEDs may be multiple. Furthermore, the light-emitting diodes may emit blue light or white light at a wavelength, but this is not a limitation of the present invention.

In this embodiment, the optical film 10 can be disposed on the side of the light guide plate 21 having the light incident surface 211. Furthermore, the optical film 10 can be the one closest to the display panel 23 among all the optical films in the display device 20. For example, the display device 20 can also include two diffusors F1 (diffusers) and one brightness enhancement film F2 (BEF), wherein the diffusors F1 and the brightness enhancement film F2 are disposed between the light guide plate 21 and the optical film 10, and the optical film 10 is closer to the display panel 23 than the diffusors F1 and the brightness enhancement film F2. It should be understood that in one embodiment, the number of diffusors F1 and the brightness enhancement film F2 is not limited to that shown in Figure 15, and the diffusors F1 and the brightness enhancement film F2 can be replaced with other types of optical films. In another embodiment, the display device 20 may include other types of optical films between the light guide plate 21 and the optical film 10 according to actual needs. The present invention is not limited to these details.

Figure 16 is a schematic cross-sectional view of the optical film and display panel of Figure 15 . Figure 17 is a schematic cross-sectional view of the optical film and display panel of a display device according to another embodiment of the present invention. Referring first to Figures 15 and 16 , the first surface 110 of the grid layer 100 faces the display panel 23; in other words, a light beam can enter the grid layer 100 via the second surface 120 and exit the grid layer 100 via the first surface 110 to be incident on the display panel 23. However, in one embodiment, such as the display device 20a shown in Figure 17 , the second surface 120 of the grid layer 100 can face the display panel 23 to provide a different effect of reducing the light output angle than the display device 20 of Figure 16 . For example, the angle of light emitted from the first surface 110 of the grid layer 100 in Figure 16 can be smaller than the angle of light emitted from the second surface 120 of the grid layer 100 in Figure 17 . Thus, the optical film 10 can be configured in the manner shown in Figure 16 or Figure 17 according to actual needs, and the present invention is not limited to this.

Referring again to FIG. 15 , the display panel 23 of this embodiment can receive the light beam emitted from the optical film 10 . The display panel 23 may include, for example, a liquid crystal display panel, but other embodiments are not limited thereto.

Compared to conventional technology, the display device 20 of this embodiment utilizes the aforementioned optical film 10, thereby improving stray light at wide viewing angles and enhancing image quality. Incidentally, in other embodiments, the optical film 10 can be replaced with optical films 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10i, 10j, 10k, or 10l.

Figure 18 is a schematic diagram of the light output pattern of a conventional display device and the light output pattern of a display device according to an embodiment of the present invention. Figure 19 is a schematic diagram of the vertical viewing angle brightness distribution of the light output pattern of a conventional display device and the display device according to an embodiment of the present invention. It should be noted that Figure 18 illustrates light intensity using dot density. A higher density of dots in the grid pattern indicates a higher brightness of the light output in that area. Conversely, a lower density of dots in the grid pattern indicates a lower intensity of the light output in that area. Referring first to Figure 18, (a) is a schematic diagram of the light output pattern of a conventional display device, while (b) is a schematic diagram of the light output pattern of a display device according to an embodiment of the present invention. The distribution density of dots representing light brightness in regions Z1 and Z2 of the display device of the present invention shown in (b) is significantly lower than that of the conventional display device shown in (a). Therefore, the display device of the present invention can effectively reduce stray light emitted at large viewing angles. Furthermore, referring to FIG19 , compared to conventional display devices, the display device of one embodiment of the present invention can reduce light intensity at relatively large vertical viewing angles, such as approximately between 50° and 90° and -50° and -90°. On the other hand, the display device of the present invention can more concentratedly emit light within relatively small vertical viewing angles, such as approximately between -40° and 40°, but the present invention is not limited thereto. Please refer to Table 1 for the full width at half maximum of the display device of an embodiment of the present invention and a conventional display device in terms of vertical and horizontal viewing angles.

Incidentally, because the display device 20 of this embodiment has a small vertical viewing angle, in one embodiment, the display device 20 can be used as a non-obstructive display device. Furthermore, in another embodiment, the display device 20 can be a vehicle display device. However, the present invention does not impose any particular limitations on the specific use of the display device 20.

In summary, the optical film of the present invention utilizes a grid layer comprising multiple light-blocking sections and multiple light-transmitting sections. Specifically, the light-blocking sections have two connected, mutually inclined surfaces (i.e., the fourth, fifth, sixth, and seventh surfaces) on opposite sides, while the light-transmitting section is located between adjacent light-blocking sections. This allows light beams passing through the light-transmitting sections to be incident on either the fourth or fifth surface, where they are then reflected and emitted from the grid layer. As a result, the light beams emerging from the grid layer have a smaller angle than the angle at which they entered the grid layer. Therefore, the optical film of the present invention can reduce stray light caused by excessively large light emission angles. Because the display device of the present invention utilizes the aforementioned optical film, it can improve stray light that occurs at wide viewing angles, thereby enhancing image quality.

However, the above descriptions are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. In other words, any simple equivalent variations and modifications made within the scope of the present invention's patent application and the contents of the invention description are still covered by the present invention. Furthermore, no single embodiment or patent application of the present invention is required to achieve all of the objects, advantages, or features disclosed herein. Furthermore, the abstract and title are intended solely to assist in searching patent documents and are not intended to limit the scope of the present invention. Furthermore, terms such as "first" and "second" in this specification or patent application are used solely to name elements or to distinguish between different embodiments or scopes, and are not intended to limit the upper or lower limits on the number of elements.

10: Optical film

100: Grid layer

110: First surface

120: Second surface

130:Light shielding part

131: Third Surface

132: Fourth Surface

133: The Fifth Surface

134: Sixth Surface

135: Seventh Surface

140: Translucent part

1340, 1350: side

A1, A2, A3, A4: Angles

B1, B2: Beams

C1: First corner

C2: Second corner

D: Direction

D1: First Direction

E1: First Edge

E2: Second Edge

E3: The Third Edge

E4: The Fourth Edge

EA, IA: Zhang Jiao

H, P: distance

IA1: First Angle

IA2: Second angle

IA3: Third Angle

IA4: Fourth Angle

L1, L2, L3, L4: Length

Claims (18)

An optical film comprises: a grid layer having a first surface, a second surface, a plurality of light-shielding portions and a plurality of light-transmitting portions, the first surface being opposite to and parallel to the second surface, the light-shielding portions and the light-transmitting portions being located between the first surface and the second surface, and the light-shielding portions and the light-transmitting portions being alternately arranged along the first surface; each of the light-shielding portions having a third surface, a fourth surface, a fifth surface, a sixth surface, and a seventh surface, the third surfaces being coplanar with the first surface, the fourth surface and the fifth surface being connected to opposite sides of the third surface, respectively, a first angle between the fourth surface and the third surface being A1, and a second angle between the fifth surface and the third surface being A2; the sixth surface being connected to the fourth surface and the second surface, the seventh surface being connected to the fifth surface and the second surface, and the sixth surface being connected to the second surface. A third angle between the seventh surface and the second surface is A3, and a fourth angle between the seventh surface and the second surface is A4; wherein 85°<A1≦90°, 85°<A2≦90°, 0°<A3<85°, 0°<A4<85°, A2≠A4, and A1≠A3; wherein the fourth surface has a first edge and a second edge opposite to each other, the first edge is adjacent to the third surface, and the second edge is connected to the sixth surface, The fifth surface has a third edge and a fourth edge opposite each other, the third edge being adjacent to the third surface, and the fourth edge being connected to the seventh surface. Each of the light-shielding portions has an imaginary plane perpendicular to the first and second surfaces, and extending from the center of the third surface to the second surface. The fourth and fifth surfaces are asymmetric with respect to the imaginary plane, and the sixth and seventh surfaces are asymmetric with respect to the imaginary plane. The optical film as described in claim 1, wherein each of the light-shielding portions further has a first corner and a second corner, the first corner being located between the fourth surface and the sixth surface, and the second corner being located between the fifth surface and the seventh surface; in a first direction from the first surface toward the second surface, the first corner and the second corner are farther from the first surface and closer to the second surface. The optical film as described in claim 1, wherein the light-shielding portions are arranged equidistantly from each other on the first surface. The optical film as described in claim 3, wherein in a direction in which the light-shielding portions and the light-transmitting portions are alternately arranged along the first surface, a distance between the third edge of the fifth surface of one light-shielding portion connected to the third surface and the third edge of the fifth surface of another adjacent light-shielding portion connected to the third surface is between 30 μm and 200 μm. The optical film as described in claim 1, wherein in a first direction from the first surface to the second surface, the distance between the first surface and the second surface is between 30 μm and 200 μm. The optical film as described in claim 1, wherein the side of the sixth surface connected to the second surface and the side of the seventh surface connected to the second surface of each of the light-shielding portions are adjacent to or not adjacent to each other. The optical film as described in claim 1, wherein any two of the light-shielding portions have different shapes. The optical film as described in claim 1 further includes a first light-transmitting plate disposed on a side of the second surface facing away from the light-shielding portions. The optical film as described in claim 8, wherein the first light-transmitting plate has a first light-transmitting surface and a second light-transmitting surface, the first light-transmitting surface and the second light-transmitting surface are opposite to each other, and the first light-transmitting surface is disposed on the side of the second surface facing away from the light-shielding portions, and the second light-transmitting surface has a plurality of first microstructures. The optical film as described in claim 8 further includes a plurality of first light scattering particles, wherein the first light scattering particles are disposed within the first light-transmitting plate. The optical film as described in claim 8 further includes a light-transmitting layer disposed between the second surface and the first light-transmitting plate. The optical film as described in claim 1 further includes a second light-transmitting plate, wherein the second light-transmitting plate is disposed on the first surface. The optical film as described in claim 12, wherein the second light-transmitting plate has a third light-transmitting surface and a fourth light-transmitting surface, the third light-transmitting surface and the fourth light-transmitting surface are opposite to each other, and the third light-transmitting surface is disposed on the first surface, and the fourth light-transmitting surface has a plurality of second microstructures. The optical film as described in claim 12 further includes a plurality of second light scattering particles, wherein the second light scattering particles are disposed in the second light-transmitting plate. The optical film as described in claim 12, wherein the second light-transmitting plate includes a brightness enhancement film. The optical film as described in claim 1, wherein the absolute value of the refractive index difference between the light-shielding portions and the light-transmitting portions is greater than 0.005. A display device includes: a light guide plate having a light incident surface and a light emitting surface, the light emitting surface being connected to the light incident surface; a light source disposed opposite the light incident surface; a display panel disposed opposite the light emitting surface; and an optical film disposed between the light emitting surface and the display panel, wherein the optical film includes: a grid layer having a first surface, a second surface, a plurality of light-shielding portions, and a plurality of light-transmitting portions, the first surface and the second surface being opposite and parallel to each other, the light-shielding portions and the light-transmitting portions being disposed between the first surface and the second surface. The light-shielding portions and the light-transmitting portions are alternately arranged along the first surface. Each of the light-shielding portions has a third surface, a fourth surface, a fifth surface, a sixth surface, and a seventh surface. The third surfaces are coplanar with the first surface. The fourth surface and the fifth surface are connected to opposite sides of the third surface, respectively. A first angle between the fourth surface and the third surface is A1, and a second angle between the fifth surface and the third surface is A2. The sixth surface The fourth surface is connected to the second surface, the seventh surface is connected to the fifth surface and the second surface, a third angle between the sixth surface and the second surface is A3, and a fourth angle between the seventh surface and the second surface is A4; wherein 85°<A1≦90°, 85°<A2≦90°, 0°<A3<85°, 0°<A4<85°, A2≠A4, and A1≠A3; wherein the fourth surface has a first edge and a second edge opposite to each other, the first edge The edge is adjacent to the third surface, the second edge is connected to the sixth surface, the fifth surface has a third edge and a fourth edge opposite to each other, the third edge is adjacent to the third surface, and the fourth edge is connected to the seventh surface; wherein each of the light-shielding portions has an imaginary plane, the imaginary plane being perpendicular to the first and second surfaces and extending from the center of the third surface to the second surface, the fourth surface and the fifth surface being asymmetric with respect to the imaginary plane, and the sixth surface and the seventh surface being asymmetric with respect to the imaginary plane. The display device as described in claim 17, wherein the first surface or the second surface faces the display panel.