TWI738465B - Display device - Google Patents

Abstract

A display device including a liquid crystal module and a backlight module is provided. The liquid crystal module includes a dual-domains liquid crystal layer, a lower polarizer and an upper polarizer. The lower polarizer has a transmission axis along a first direction. The backlight module includes a light emitting module, a first prism sheet, a second prism sheet, a reflective-polarizing film and a light expanding film. The reflective-polarizing film has a transmission axis along a third direction, wherein an angle between the third direction and the first direction falls within a range of 0±5 degrees. The light expanding film has a plurality of first microstructures extending along a first extension direction. A light emitted by the light emitting module is emitted through a light emitting surface of an optical plate, and then sequentially passes through the first prism sheet, the second prism sheet, the reflective-polarizing film, the light expanding film and the liquid crystal module to form an image light.

Description

Display device

The present invention relates to an optical module, and particularly relates to a display device.

Due to the development of electronic products such as TVs, computers, laptops, mobile devices, and smart phones, the improvement of the experience of display devices has become a trend in the market. Existing display devices, for example, use a multi-domain vertical alignment (VA) liquid crystal layer to improve the color washout problem (color washout) of the display screen presented by the display device at a large viewing angle. In addition, in order to improve the problem of poor gamma (Gamma) value of the display screen at a large viewing angle, the display device can use a multi-domain coplanar switching (In-Plane-Switching, IPS) liquid crystal layer, or the display device can be used in multiple A microstructure film is arranged on the domain vertical alignment type liquid crystal layer.

However, the cost of providing the microstructure film is high, which increases the overall cost of the display device and makes the contrast of the display screen of the display device poor. Furthermore, although the higher the number of domains of the liquid crystal layer can reduce the color shift problem of the display screen, it also causes the poor utilization of light energy of the display device and the poor brightness of the display screen. Conversely, for display devices with a small number of areas of the liquid crystal layer, such as a dual-domain liquid crystal layer, the display device also has the problem of asymmetrical light shape of the surface light source provided by the backlight module of the display device due to the matching method of the various layers. , And at the lowest gray level, there is also the problem of light leakage at the large viewing angles of the vertical viewing angle and the horizontal viewing angle.

The present invention provides a display device, which can effectively reduce the problem of asymmetry of the light shape of the surface light source and the problem of light leakage at a large viewing angle when the display picture presented by the display device is at the lowest gray level.

The display device of an embodiment of the present invention includes a liquid crystal module and a backlight module. The liquid crystal module includes a dual domain liquid crystal layer, a lower polarizer and an upper polarizer. The liquid crystal molecules of the dual-domain liquid crystal layer are arranged along a horizontal arrangement direction when no voltage is applied. The lower polarizer has a penetration axis along a first direction, wherein the corner between the first direction and the horizontal arrangement direction is within a range of 45±5 degrees. The upper polarizer has a penetration axis along a second direction. The lower polarizer, the dual domain liquid crystal layer and the upper polarizer are arranged in sequence in an arrangement direction. The backlight module is used to provide a surface light source. The backlight module includes a light emitting module, a first light emitting film, a second light emitting film, a reflective polarization film and a light diffusing film. The light emitting module includes an optical plate and a light source. The optical plate has a light-emitting surface and a light-incident surface. The light source is arranged on one side of the light incident surface of the optical plate. The reflective polarization film has a penetration axis along a third direction, wherein the corner between the third direction and the first direction is within a range of 0±5 degrees. The light diffusing film has a plurality of first microstructures extending along a first extending direction. The light emitting module, the first light emitting film, the second light emitting film, the reflective polarizing film, the light diffusing film and the liquid crystal module are arranged in sequence in the arrangement direction. The light emitted by the light-emitting module is emitted through the light-emitting surface of the optical plate, and then sequentially passes through the first film, the second film, the reflective polarization film, the light diffusing film and the liquid crystal module to form an image Light.

Based on the above, in the display device of an embodiment of the present invention, because the reflective polarizing film is provided with a light-diffusing film and the combination of each film layer in the display device, the backlight module of the display device provides The light shape of the surface light source is better, and the display effect of the display device is better.

Reference will now be made in detail to the exemplary embodiments of the present invention, and examples of the exemplary embodiments are illustrated in the accompanying drawings. Whenever possible, the same component symbols are used in the drawings and descriptions to indicate the same or similar parts.

It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element, or Intermediate elements can also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements. As used herein, "connected" can refer to physical and/or electrical connection. Furthermore, "electrically connected" or "coupled" may mean that there are other elements between two elements.

As used herein, "about", "approximately", or "substantially" includes the stated value and the average value within the acceptable deviation range of the specific value determined by a person of ordinary skill in the art, taking into account the measurement in question and the The specific amount of measurement-related error (ie, the limitation of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or within ±30%, ±20%, ±10%, ±5%. Furthermore, "about", "approximately" or "substantially" as used herein can be based on optical properties, etching properties or other properties to select a more acceptable range of deviation or standard deviation, and not one standard deviation can be applied to all properties .

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with their meanings in the context of related technologies and the present invention, and will not be interpreted as idealized or excessive The formal meaning, unless explicitly defined as such in this article.

FIG. 1 is a three-dimensional exploded view of a display device according to an embodiment of the invention. Please refer to FIG. 1, a display device 10 according to an embodiment of the present invention includes a liquid crystal module 100 and a backlight module 200. The liquid crystal module 100 includes a two domains liquid crystal layer 110, a lower polarizer 120 and an upper polarizer 130. The lower polarizer 120, the dual-domain liquid crystal layer 110, and the upper polarizer 130 are sequentially arranged in an arrangement direction A. The backlight module 200 includes a light emitting module 210, a first light emitting film 220, a second light emitting film 230, a reflective polarization film 240, and a light diffusing film 250. The light emitting module 210, the first light emitting film 220, the second light emitting film 230, the reflective polarizing film 240, the light diffusing film 250, and the liquid crystal module 100 are arranged in sequence in the arrangement direction A.

In detail, the liquid crystal molecules of the dual domain liquid crystal layer 110 of this embodiment are arranged along a horizontal arrangement direction H when no voltage is applied. The lower polarizer 120 has a penetration axis along a first direction D1, wherein the corner between the first direction D1 and the horizontal arrangement direction H is within a range of 45±5 degrees. The upper polarizer 130 has a transmission axis along a second direction D2, wherein the corner between the second direction D2 of the upper polarizer 130 and the first direction D1 of the lower polarizer 120 is within a range of 90±5 degrees. In an embodiment, the second direction D2 and the first direction D1 are preferably perpendicular to each other.

In this embodiment, the backlight module 200 is used to provide a surface light source. Specifically, the backlight module 200 indicates that the light module 210 includes an optical plate 212 and a light source 214. The optical plate 212 has a light-emitting surface 212S1 and a light-incident surface 212S2. The light source 214 is arranged on one side of the light incident surface 212S2 of the optical plate 212. Furthermore, the light source 214 is, for example, a light-emitting diode (LED) light source, a sub-millimeter light-emitting diode (mini LED) light source, or other suitable light sources. The light emitted by the light-emitting module 210 is emitted through the light-emitting surface 212S1 of the optical plate 212, and then sequentially passes through the first sheet 220, the second sheet 230, the reflective polarization film 240, the light diffusing film 250, and the liquid crystal The module 100 forms an image light. FIG. 1 illustrates that the light-emitting surface 212S1 of the optical plate 212 is adjacent to the light-incident surface 212S2. In other words, the optical plate 212 in FIG. 1 may be a light guide plate, but the present invention is not limited to this. In one embodiment, the optical plate may be a diffuser plate, and the light-emitting surface is opposite to the light-incident surface. In other words, the light source is arranged under the optical plate. In the display device 10 of an embodiment of the present invention, when the optical plate 212 is a light guide plate, the overall volume of the display device 10 is small; when the optical plate is a diffuser plate, since the light source is arranged under the optical plate, the backlight module The light shape of the group can be adjusted by the position of the light source, so the light shape of the backlight module is more uniform.

In one embodiment, the backlight module 200 further includes a quantum dots layer 260 disposed on the optical plate 212, and the light source 214 includes a blue light source. The quantum dot layer 260 is disposed between the optical plate 212 and the first sheet 220. In another embodiment, the quantum dot layer 260 can be directly disposed on the light-emitting surface 212S1 of the optical plate 212. In the display device 10 of an embodiment of the present invention, since the backlight module 200 includes the quantum dot layer 260, the surface light source provided by the backlight module 200 has better color rendering properties.

In this embodiment, the reflective polarization film 240 has a penetration axis along a third direction D3, wherein the corner between the third direction D3 and the first direction D1 is within a range of 0±5 degrees. In an embodiment, the third direction D3 and the first direction D1 are preferably parallel to each other.

2 is a cross-sectional view of a light diffusing film of a display device according to an embodiment of the invention. Please refer to FIG. 1 and FIG. 2 at the same time. In this embodiment, the light diffusing film 250 has a plurality of first microstructures 252 extending along a first extension direction E1. Specifically, the light diffusing film 250 includes a substrate 254, and the first microstructure 252 is disposed on the substrate 254 on the upper surface 254S opposite to the optical plate 212, but the present invention is not limited thereto. Furthermore, the first microstructure 252 has a plurality of first turning regions 252F. The first turning area 252F is the height difference L′ of the first microstructure 252 between each local extremum relative to the surface 252S of the optical plate 212 and its adjacent local extremum along the arrangement direction A. The area in the range of 0 to 10%, where the height is the distance between the surface 252S of the first microstructure 252 and the upper surface 254S of the substrate 254. The extension direction of the first turning area 252F is perpendicular to the arrangement direction of the first microstructures 252. Incidentally, in the first turning area 252F1 of FIG. 2, the first turning area 252F1 includes the local extreme values LM2, LM3, and LM4. The first turning area of the local extremum LM2 is an area in which the height difference between the adjacent local extremums LM1 and LM3 falls within a range of 0 to 10%. In the same way, the first turning zone of the local extremum LM3 is the area where the height difference between the adjacent local extremums LM2 and LM4 falls within the range of 0 to 10%, and the first turning zone of the local extremum LM4 It is the area where the height difference between the adjacent local extreme values LM3 and LM5 falls within the range of 0 to 10%. Therefore, for the convenience of illustration, the first turning area 252F1 of FIG. 2 includes the aforementioned three first turning areas of local extrema LM2, LM3, and LM4.

In this embodiment, the ratio of the projection area of the first turning area 252F on the upper surface 254S of the light diffusing film 250 relative to the optical plate 212 to the projection area of the first microstructure 252 on the upper surface 254S of the light diffusing film 250 is greater than or equal to 30% and less than or equal to 60%.

FIG. 3 is a graph of the luminance gain ratio of the display device according to an embodiment of the present invention with respect to the average height L/average pitch P between the first microstructures. Please refer to FIGS. 2 and 3 at the same time. In this embodiment, the first microstructure 252 of the light diffusing film 250 also satisfies the following condition: 4%≦L/P≦25%, where L is the average of the first microstructure 252 The height difference, and P is the average pitch of the first microstructure 252. Figure 3 shows that different L/Ps produce different luminance gain rates. In a preferred embodiment, L/P=4%.

4 is a cross-sectional view of an upper polarizer of a display device according to an embodiment of the invention. Please refer to FIGS. 1 and 4 at the same time. In this embodiment, the upper polarizer 130 has a plurality of second microstructures 132 along a second extension direction E2, wherein the distance between the second extension direction E2 and the horizontal arrangement direction H The included angle is less than or equal to 20 degrees. Specifically, the upper polarizer 130 includes a substrate 134, and the second microstructure 132 is disposed on the substrate 134 on the upper surface 134S opposite to the optical plate 212, but the present invention is not limited thereto. Furthermore, the second microstructure 132 has a plurality of second turning regions 132F. The second turning area 132F is the height difference L′ of the second microstructure 132 along the arrangement direction A between each local extremum of the surface 132S of the optical plate 212 and its adjacent local extremum. The area in the range of 0 to 10%, where the height is the distance between the surface 132S of the second microstructure 132 and the upper surface 134S of the substrate 134. The extension direction of the second turning area 132F is perpendicular to the arrangement direction of the second microstructure 132.

In this embodiment, the ratio of the projection area of the second turning area 132F on the upper polarizer 130 relative to the upper surface 134S of the optical plate 212 to the projection area of the second microstructure 132 on the upper surface 134S of the upper polarizer 130 is greater than or equal to 85% and 93% or less.

5A is a graph of the gamma value versus gray scale in the vertical viewing angle direction of the display device without the second microstructure on the upper polarizer according to an embodiment of the present invention. FIG. 5B is a graph of the gamma value in the vertical viewing angle direction with respect to the gray scale in the display device with the upper polarizer provided with the second microstructure in an embodiment of the present invention. Please refer to FIG. 5A and FIG. 5B. In FIG. 5A, curves C1, C3, and C5 are graphs of gamma values versus gray scales with viewing angles of 30, 45, and 60 degrees in the vertical viewing direction, respectively; in FIG. 5B Among them, the curves C2, C4, and C6 are graphs of gamma values versus gray scales with viewing angles of 30, 45, and 60 degrees in the vertical viewing angle direction, respectively. Among them, the average gamma value of curve C1 is about 1.2, and the average gamma value of curve C2 is about 1.3; the average gamma value of curve C3 is about 0.5, and the average gamma value of curve C4 is about 0.8; curve C5 The average gamma value of is about -0.1, and the average gamma value of curve C6 is about 0.5. That is to say, when the second microstructure 132 is provided on the upper polarizer 130 in the display device 10 of an embodiment of the present invention, the overall gamma value of the display device 10 is better, and the second microstructure 132 has a better The arrangement also overcomes the problem of grayscale inversion of the display device at a large viewing angle in the vertical viewing angle direction.

FIG. 6A is a cross-sectional view of the first or second ridge of the display device according to an embodiment of the present invention. Please refer to FIG. 1 and FIG. 6A at the same time. In FIG. 1, in order to clearly show the structure of the first microstructure 222 and the second microstructure 232, FIG. 1 only shows a first microstructure 222 and The second 稜鏡 microstructure 232. In this embodiment, the first scallop sheet 220 has a plurality of first scallop microstructures 222 extending along a third extension direction E3, wherein the corner between the third extension direction E3 and the first direction D1 is 90± Within 20 degrees. The second scallop sheet 230 has a plurality of second scallop microstructures 232 extending along a fourth extension direction E4, wherein the included angle between the fourth extension direction E4 and the first direction D1 is less than or equal to 20 degrees. In one embodiment, the third extension direction E3 and the fourth extension direction E4 are preferably perpendicular to each other.

In this embodiment, the corner between the first extension direction E1 of the light diffusing film 250 and the fourth extension direction E4 of the second scallop 230 is within a range of 45±10 degrees.

Specifically, the first ridge sheet 220 of this embodiment includes a substrate 224, and the first ridge microstructure 222 is disposed on the substrate 224 on the upper surface 224S1 opposite to the optical plate 212, but the invention is not limited thereto. Furthermore, the first microstructure 222 has a plurality of third turning regions 222F. The third turning area 222F is the height difference L between each local extremum of the first microstructure 222 relative to the surface 222S of the optical plate 212 and its adjacent local extremum along the arrangement direction A. The area falling within the range of 0 to 10%, where the height is the distance between the surface 222S of the first microstructure 222 and the upper surface 224S1 of the substrate 224. The extension direction of the third turning area 222F is perpendicular to the arrangement direction of the first ridged microstructures 222.

In the present embodiment, the projection area of the third turning area 222F on the upper surface 224S1 of the first ridge sheet 220 relative to the optical plate 212 and the projection area of the first ridge microstructure 222 on the upper surface 224S1 of the first ridge sheet 220 The ratio of is greater than or equal to 21% and less than or equal to 25%.

Similarly, the second sheet 230 of this embodiment includes a substrate 234, and the second microstructure 232 is disposed on the substrate 234 on the upper surface 234S1 opposite to the optical plate 212, but the invention is not limited thereto. Furthermore, the second microstructure 232 has a plurality of fourth turning regions 232F. The fourth turning area 232F is the height difference L along the arrangement direction A between each local extremum of the second 稜鏡 microstructure 232 relative to the surface 232S of the optical plate 212 and its adjacent local extremum. The area falling within the range of 0 to 10%, where the height is the distance between the surface 232S of the second microstructure 232 and the upper surface 234S1 of the substrate 234. The extension direction of the fourth turning area 232F is perpendicular to the arrangement direction of the second ridged microstructures 232.

In the present embodiment, the projection area of the fourth turning area 232F on the upper surface 234S1 of the second optical plate 230 relative to the optical plate 212 and the projected area of the second microstructure 232 on the upper surface 234S1 of the second optical plate 230 The ratio of is greater than or equal to 21% and less than or equal to 25%.

Fig. 6B is a partial enlarged view of Fig. 6A in the first microstructure or the second microstructure. Please refer to FIG. 6B. In this embodiment, the tips 222T and 232T of the first microstructure 222 and the second microstructure 232 relative to the optical plate 212 may be rounded. Furthermore, the radius of curvature R2 of the tip 232T of each second microstructure 232 is less than or equal to the radius of curvature R1 of the tip 232T of each first microstructure 222.

FIG. 7 is a display device according to an embodiment of the present invention, the radius of curvature of the tip of the first ridge microstructure of the first ridge is greater than and smaller than the radius of curvature of the second ridge of the second ridge of the second plate in the display device according to an embodiment of the present invention. The curve graph of the relative luminance value of the horizontal viewing angle direction with respect to the viewing angle when the radius of curvature of the tip is at the lowest gray level. The curve C7 in FIG. 7 shows that the radius of curvature R1 of the tip 222T of the first microstructure 222 is smaller than the radius of curvature R2 of the tip 232T of the second microstructure 232, where R1 is 0.5 microns, and R2 is 7 microns; the curve C8 is that the radius of curvature R1 of the tip 222T of the first microstructure 222 is greater than the radius of curvature R2 of the tip 232T of the second microstructure 232, where R1 is 7 microns, and R2 is 0.5 Micrometers. Please refer to FIG. 7, in the display device 10 of an embodiment of the present invention, when the radius of curvature R2 of the ridge tip 232T of the second ridge microstructure 232 is less than or equal to that of the ridge tip 232T of the first ridge microstructure 222 With the radius of curvature R1, the problem of light leakage at a large viewing angle of the display device 10 at the lowest gray level is improved.

In this embodiment, the refractive index of the second sheet 230 is greater than or equal to the refractive index of the first sheet 220. 8 is a display device according to an embodiment of the present invention, the refractive index of the first film is greater than and smaller than the refractive index of the second film at the lowest gray level and the relative luminance value in the horizontal viewing angle direction is relatively A graph based on the viewing angle. Curve C9 in FIG. 8 indicates that the refractive index of the first sheet 220 is 1.65, and the refractive index of the second sheet 230 is 1.52; the curve C10 indicates that the refractive index of the first sheet 220 is 1.52, and the refractive index of the second sheet 230 is 1.65. Referring to FIG. 8, in the display device 10 of an embodiment of the present invention, when the refractive index of the second sheet 230 is greater than or equal to the refractive index of the first sheet 220, the display device 10 is at the lowest gray scale The problem of light leakage at large viewing angles has also been improved.

Please refer to FIG. 6A again. In one embodiment, the first ridge sheet 220 and the second ridge sheet 230 respectively have a first atomization structure layer 226 and a second atomization structure on the lower surface 224S2, 234S2 facing the optical plate 212 The structure layer 236, wherein the haze of the second atomized structure layer 236 is preferably less than or equal to the haze of the first atomized structure layer 226. 9 is a display device according to an embodiment of the present invention, the haze of the first atomized structure layer of the first sheet is greater than and smaller than the haze of the second atomized structure layer of the second sheet at the lowest gray level Time and horizontal viewing angle relative brightness value versus viewing angle curve. The curve C11 in FIG. 9 indicates that the haze of the first atomization structure layer 226 is 3%, and the haze of the second atomization structure layer 236 is 8%; the curve C12 indicates the fog of the first atomization structure layer 226 The degree is 8%, and the haze of the second atomization structure layer 236 is 3%. Please refer to FIG. 9, in the display device 10 of an embodiment of the present invention, when the haze of the second atomized structure layer 236 is less than or equal to the haze of the first atomized structure layer 226, the display device 10 is at the lowest gray level. The problem of light leakage at large viewing angles has also been improved.

FIG. 10A is an example of a light shape of a display device according to an embodiment of the present invention. FIG. 10B is an example of the light-emitting shape of the backlight module of the display device according to an embodiment of the present invention. 10A and 10B illustrate that the first extension direction E1 of the light diffusing film 250 of the display device 10 and the backlight module 200 is 0 degrees in the axial direction, and the third direction D3 of the reflective polarizing film 240 is 45 degrees in the axial direction. , The fourth extension direction E4 of the second ridge piece 230 is 45 degrees in the axial direction, and the third extension direction E3 of the first ridge piece 220 is 135 degrees in the axial direction. 10A and 10B, in the display device 10 of an embodiment of the present invention, due to the arrangement of the mold layers of the display device 10, the light output of the backlight module 200 is more symmetrical and collimated, and the display device 10 is The light shape of the displayed display screen is also more symmetrical.

FIG. 11A is a graph of the relative luminance value in the horizontal viewing angle direction with respect to the viewing angle of the display device according to an embodiment of the present invention at the lowest gray level. FIG. 11B is a graph of the relative luminance value in the vertical viewing angle direction with respect to the viewing angle of the display device according to an embodiment of the present invention at the lowest gray level. The curves C13 and C15 in FIGS. 11A and 11B show that the display device is not provided with a light-diffusing film, and the third direction of the reflective polarizing film is 45 degrees in the axial direction, and the fourth extension direction of the second thin film is in the axial direction. 150 degrees, and the third extension direction of the first film is 60 degrees in the axial direction; curves C14 and C16 are the first extension direction E1 of the light diffusing film 250 of the display device at 0 degrees in the axial direction, the reflective polarization film The third direction D3 of the sheet 240 is at 45 degrees in the axial direction, the fourth extension direction E4 of the second sheet 230 is at 45 degrees in the axial direction, and the third direction E3 of the first sheet 220 is at 135 degrees in the axial direction. Please refer to FIGS. 11A and 11B. In the display device 10 of an embodiment of the present invention, due to the arrangement of the various modes of the display device 10, the vertical viewing angle and the horizontal viewing angle of the display device 10 at the lowest gray level are at the peak of the large viewing angle. It is reduced by 40%. Therefore, the problem of light leakage of the vertical viewing angle and the large viewing angle of the horizontal viewing angle of the display device 10 at the lowest gray level is effectively improved.

In addition, in this embodiment, the average gamma value of the image light in the range of 32 to 192 gray scale values along the 60-degree viewing angle of the liquid crystal module 10 is greater in the horizontal viewing angle direction than in the vertical viewing angle direction.

In summary, in the display device of an embodiment of the present invention, because the reflective polarizing film is provided with a light-diffusing film and the combination of various layers in the display device, the backlight module of the display device The light shape of the provided surface light source is more symmetrical and collimated, and the problem of light leakage from the vertical viewing angle and the horizontal viewing angle of the display device at the lowest gray level is effectively improved. In addition, the display device adopts a dual-domain liquid crystal layer, so the brightness performance of the display device is better.

10: Display device

100: LCD module

110: Dual domain liquid crystal layer

120: Lower polarizer

130: upper polarizer

132: The second microstructure

132F: The second turning area

132S, 252S, 222S, 232S: surface

134, 224, 234, 254: substrate

134S, 224S1, 234S1, 254S: upper surface

200: Backlight module

210: Light emitting module

212: Optical Board

212S1: Glossy surface

212S2: Glossy surface

214: light source

220: The first 稜鏡 piece

222: The first microstructure

222F: The third turning area

222T, 232T: tip

224S2, 234S2: bottom surface

226: The first atomization structure layer

230: The second 稜鏡 piece

232: The second microstructure

232F: The third turning area

236: The second atomization structure layer

240: Reflective polarization diaphragm

250: light diffusion film

252: The first microstructure

252F, 252F1: the first turning area

260: Quantum dot layer

A: Arrangement direction

C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16: Curve

D1: First direction

D2: second direction

D3: Third party

E1: The first extension direction

E2: second extension direction

E3: Third extension direction

E4: Fourth extension direction

H: Horizontal arrangement direction

L’: Height difference

LM1, LM2, LM3, LM4, LM5: local extremum

P: Pitch

R1, R2: radius of curvature

FIG. 1 is a three-dimensional exploded view of a display device according to an embodiment of the invention. 2 is a cross-sectional view of a light diffusing film of a display device according to an embodiment of the invention. FIG. 3 is a graph of the luminance gain ratio of the display device according to an embodiment of the present invention with respect to the average height L/average pitch P between the first microstructures. 4 is a cross-sectional view of an upper polarizer of a display device according to an embodiment of the invention. 5A is a graph of the gamma value versus gray scale in the vertical viewing angle direction of the display device without the second microstructure on the upper polarizer according to an embodiment of the present invention. FIG. 5B is a graph of the gamma value in the vertical viewing angle direction with respect to the gray scale in the display device with the upper polarizer provided with the second microstructure in an embodiment of the present invention. FIG. 6A is a cross-sectional view of the first or second ridge of the display device according to an embodiment of the present invention. Fig. 6B is a partial enlarged view of Fig. 6A in the first microstructure or the second microstructure. FIG. 7 is a display device according to an embodiment of the present invention, the radius of curvature of the tip of the first ridge microstructure of the first ridge is greater than and smaller than the radius of curvature of the second ridge of the second ridge of the second plate in the display device according to an embodiment of the present invention. The curve graph of the relative luminance value of the horizontal viewing angle direction with respect to the viewing angle when the radius of curvature of the tip is at the lowest gray level. 8 is a display device according to an embodiment of the present invention, the refractive index of the first film is greater than and smaller than the refractive index of the second film at the lowest gray level and the relative luminance value in the horizontal viewing angle direction is relatively A graph based on the viewing angle. 9 is a display device according to an embodiment of the present invention, the haze of the first atomized structure layer of the first sheet is greater than and smaller than the haze of the second atomized structure layer of the second sheet at the lowest gray level Time and horizontal viewing angle relative brightness value versus viewing angle curve. FIG. 10A is an example of a light shape of a display device according to an embodiment of the present invention. FIG. 10B is an example of the light-emitting shape of the backlight module of the display device according to an embodiment of the present invention. FIG. 11A is a graph of the relative luminance value in the horizontal viewing angle direction with respect to the viewing angle of the display device according to an embodiment of the present invention at the lowest gray level. FIG. 11B is a graph of the relative luminance value in the vertical viewing angle direction with respect to the viewing angle of the display device according to an embodiment of the present invention at the lowest gray level.

10: Display device

100: LCD module

110: Dual domain liquid crystal layer

120: Lower polarizer

130: upper polarizer

132: The second microstructure

200: Backlight module

210: Light emitting module

212: Optical Board

212S1: Glossy surface

212S2: Glossy surface

214: light source

220: The first 稜鏡 piece

222: The first microstructure

230: The second 稜鏡 piece

232: The second microstructure

240: Reflective polarization diaphragm

250: light diffusion film

252: The first microstructure

260: Quantum dot layer

A: Arrangement direction

D1: First direction

D2: second direction

D3: Third party

E1: The first extension direction

E2: second extension direction

E3: Third extension direction

E4: Fourth extension direction

H: Horizontal arrangement direction

Claims (19)

A display device includes: a liquid crystal module, including: a dual domain liquid crystal layer, wherein the liquid crystal molecules of the dual domain liquid crystal layer are arranged along a horizontal arrangement direction when no voltage is applied; A penetration axis in one direction, wherein the corner between the first direction and the horizontal arrangement direction is within a range of 45±5 degrees; and an upper polarizer having a penetration axis in a second direction, wherein the The lower polarizer, the dual domain liquid crystal layer, and the upper polarizer are sequentially arranged in an arrangement direction; and a backlight module for providing a surface light source. The backlight module includes: a light emitting module, including: a The optical plate has a light-emitting surface and a light-incident surface; and a light source disposed on one side of the light-incident surface of the optical plate; a first optical plate; a second optical plate; a reflective polarization film Sheet, having a penetration axis along a third direction, wherein the corner between the third direction and the first direction is within a range of 0±5 degrees; and a light-diffusing film having a plurality of first The first microstructure extending in the extension direction; The light emitting module, the first light emitting film, the second light emitting film, the reflective polarization film, the light diffusing film and the liquid crystal module are arranged in sequence in the arrangement direction, and the light emitting module The emitted light is emitted through the light-emitting surface of the optical plate, and then sequentially passes through the first film, the second film, the reflective polarizing film, the light diffusing film and the liquid crystal module, and An image light is formed, wherein the refractive index of the second sheet is greater than or equal to the refractive index of the first sheet. The display device according to claim 1, wherein the corner between the second direction of the upper polarizer and the first direction of the lower polarizer is within a range of 90±5 degrees, and the upper polarizer has A plurality of second microstructures along a second extension direction, the included angle between the second extension direction and the horizontal arrangement direction is less than or equal to 20 degrees. The display device according to claim 2, wherein the first ridge sheet has a plurality of first ridged microstructures extending along a third extending direction, wherein the corner between the third extending direction and the first direction Within the range of 90±20 degrees. The display device according to claim 3, wherein the second ridge sheet has a plurality of second ridged microstructures extending along a fourth extension direction, wherein the included angle between the fourth extension direction and the first direction is less than Equal to 20 degrees. The display device according to claim 4, wherein the corner between the first extension direction of the light-diffusing film and the fourth extension direction of the second sheet is within a range of 45±10 degrees. The display device according to claim 5, wherein the first microstructures, the second microstructures, the first microstructures and the second microstructures are separated There are multiple first turning areas, multiple second turning areas, multiple third turning areas, and multiple fourth turning areas, the first turning areas, the second turning areas, and the third turning areas And the fourth turning regions are the first microstructures, the second microstructures, the first microstructures, and the second microstructures on each surface relative to the optical plate. The area where the height difference between a local extreme value and its neighboring local extreme values along the arrangement direction falls within a range of 0 to 10%; the first turning areas and the second turning areas , The extension directions of the third turning regions and the fourth turning regions are respectively perpendicular to the first microstructures, the second microstructures, the first microstructures, and the second microstructures. The direction of the arrangement of the structure. The display device according to claim 6, wherein the projection area of the first turning areas on the upper surface of the light-expanding film relative to the optical plate and the difference between the first microstructures on the upper surface of the light-expanding film The ratio of the projected area is greater than or equal to 30% and less than or equal to 60%. The display device according to claim 6, wherein the projection area of the second turning areas on the upper polarizer relative to the upper surface of the optical plate and the projection area of the second microstructures on the upper surface of the upper polarizer The ratio of the projected area is greater than or equal to 85% and less than or equal to 93%. The display device according to claim 6, wherein the projected area of the third turning areas on the upper surface of the first optical plate and the projection area of the first optical microstructures on the first optical plate The ratio of the projected area of the upper surface is greater than or equal to 21% and less than or equal to 25%. The display device according to claim 6, wherein the projection area of the fourth turning areas on the second ridge sheet relative to the upper surface of the optical plate and the second ridge microstructures on the second ridge sheet The ratio of the projected area of the upper surface is greater than or equal to 21% and less than or equal to 25%. The display device according to claim 1, wherein the average height difference of the first microstructures is L, the average pitch is P, and 4%≦L/P≦25%. The display device according to claim 4, wherein the radius of curvature of each second ridge microstructure relative to the ridge tip of the optical plate is less than or equal to the edge of each first ridge microstructure relative to the optical plate The radius of curvature of the mirror tip. The display device according to claim 1, wherein the first ridge sheet and the second ridge sheet respectively have a first atomization structure layer and a second atomization structure layer on the lower surface facing the optical plate, and the first atomization structure layer The haze of the second atomization structure layer is less than or equal to the haze of the first atomization structure layer. The display device according to claim 1, wherein the optical plate is a light guide plate, and the light-emitting surface is adjacent to the light-incident surface. The display device according to claim 1, wherein the optical plate is a diffuser plate, and the light-emitting surface is opposite to the light-incident surface. The display device according to claim 1, wherein the backlight module further includes a quantum dot layer disposed on the optical plate, and the light source includes a blue light source. The display device according to claim 16, wherein the quantum dot layer is disposed between the optical plate and the first sheet. The display device according to claim 1, wherein the average gamma value of the image light in the range of 32 to 192 gray scale values along the 60-degree viewing angle of the liquid crystal module is greater in the horizontal viewing angle direction than in the vertical viewing angle direction. The display device according to claim 2, wherein the average gamma value of the image light in the range of 32 to 192 gray scale values along the 60-degree viewing angle of the liquid crystal module is greater in the horizontal viewing angle direction than in the vertical viewing angle direction.

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