TWI648577B - Reflecting layer design method and display device thereof - Google Patents

Abstract

The invention provides a design method of a reflective layer and a display device thereof, wherein the design method of the reflective layer is suitable for a display device. The display device includes a first substrate, a display medium layer, a reflective layer, and a second substrate. The design method of the reflective layer includes selecting a viewing angle θ _{2 for} viewing the display device; providing an optical film on the first substrate and the refraction angle of light passing through the optical film is θ ₂ ′; and forming the reflective layer with a plurality of convex structures, everything The line is tangent to the surface of the convex structure, and there is an angle α between the tangent line and the plane where the reflective layer is located. The angle α conforms to the following formula, so that the display device can be viewed at the viewing angle θ ₂ : α = (θ ₁ + θ ₂ ′ -θ ₂ ) / 2 where θ ₁ is the original angle of incidence of light rays toward the reflective layer.

Description

Design method of reflective layer and display device thereof

The present invention relates to a design method of a display device structure, and particularly to a design method of a reflective layer and a display device suitable for the design method.

A transflective display device or a reflective display device can use a reflective layer to reflect the ambient light passing through the display medium layer to complete the display operation, so it is suitable for outdoor use. Generally speaking, the best viewing direction can be obtained at the position where the reflected light exits the display device, otherwise it is not. In other words, in the current transflective display device or reflective display device, the viewing angle for viewing the display device is limited. In addition, although good reflectivity can be obtained at the position where the reflected light exits the display device, the reflectance at other positions is not improved, resulting in low display quality of the display device.

The invention provides a design method of a reflective layer, which can provide a display device with excellent display quality.

The invention provides a display device with good display quality.

The design method of the reflective layer of the present invention is suitable for a display device. The display device includes a first substrate, a display medium layer, a reflective layer, and a second substrate. The design method of the reflective layer includes selecting a viewing angle θ _{2 for} viewing the display device; providing an optical film on the first substrate, and a refractive angle of light passing through the optical film is θ ₂ ′; and forming the reflective layer with a plurality of convex structures. All the lines are tangent to the surface of the convex structure, and there is an angle α between the tangent line and the plane where the reflective layer is located. The angle α conforms to the following formula, so that the display device can be viewed at a viewing angle θ ₂ : α = (θ ₁ + θ ₂ '-θ ₂ ) / 2 where θ ₁ is the original angle of incidence of light rays toward the reflective layer.

The display device of the present invention is suitable for viewing at a viewing angle θ ₂ . The display device includes a first substrate, a second substrate opposite to the first substrate, a display medium layer between the first substrate and the second substrate, an optical film on the first substrate, and a layer between the second substrate and the display medium layer Reflective layer. The refraction angle of light passing through the optical film is θ ₂ ′. The reflective layer has multiple convex structures. All the lines are tangent to the surface of the convex structure, and there is an angle α between the tangent line and the plane where the reflective layer is located. The angle α conforms to the following formula, so that the display device can be viewed at a viewing angle θ ₂ : α = (θ ₁ + θ ₂ '-θ ₂ ) / 2 where θ ₁ is the original angle of incidence of light rays toward the reflective layer.

In an embodiment of the invention, θ ₂ may be between -60∘ and + 60∘.

In an embodiment of the invention, θ ₂ ′ may be between -30∘ and + 30∘.

In an embodiment of the present invention, the scattering angle of light passing through the optical film is δ, so that the viewing angle for viewing the display device may be between θ ₂ -δ and θ ₂ + δ.

In an embodiment of the invention, δ may be between -45∘ and + 45∘.

In an embodiment of the invention, the convex structure may be a symmetrical or asymmetrical convex structure.

Based on the above, the reflective layer according to an embodiment of the present invention is formed with a convex structure conforming to the above formula, so that incident light can be reflected through the convex structure to a selected viewing angle. In addition, the reflectivity around the selected viewing angle can be increased through the optical film. As a result, the problems of limited viewing angle and low display quality of the transflective display device or the reflective display device described in the prior art can be improved.

In order to make the above-mentioned features and advantages of the present invention more obvious and understandable, the embodiments are specifically described below and described in detail in conjunction with the accompanying drawings.

Hereinafter, specific embodiments will be described in more detail with reference to the drawings. However, the present invention can be embodied in different forms, and the present invention should not be construed as being limited to the embodiments set forth herein. Specifically, these embodiments are provided so that the present invention will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the drawings, for clarity of description, various features are not drawn to scale, wherein the size of various features may be exaggerated or reduced, and the same or corresponding symbols refer to the same or corresponding elements.

It should be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited to these terms. These terms are only used to distinguish each element. Therefore, the first element may be simply referred to as an element without departing from the teaching content of the embodiments of the present invention.

2 is a schematic diagram of a display device according to an embodiment of the invention.

Referring to FIG. 2 first, the display device 100 includes a first substrate 102, a second substrate 104, a display medium layer 106, an optical film 110, and a reflective layer 108. However, the present invention is not limited to this, and other layers or components commonly used in the display device, such as color filter layers or active elements, etc., can be selectively provided in the display device 100 according to actual requirements, without particular limitation. In this embodiment, the second substrate 104 is opposite to the first substrate 102, the display medium layer 106 is located between the first substrate 102 and the second substrate 104, the optical film 110 is located on the first substrate 102, and the reflective layer 108 is located on the second Between the substrate 104 and the display medium layer 106. Display device 100 for viewing perspective [theta] _2, [theta] ₂ is defined as a viewing angle to the normal line of sight of the eye NL3 (perpendicular to the first substrate 102) included angle between the viewing angle [theta] ₂ + 60∘ to be interposed between -60∘ .

In an embodiment of the invention, the materials of the first substrate 102 and the second substrate 104 may be the same or different. Furthermore, the material of the first substrate 102 is a light-transmitting material, and the material of the second substrate 104 may be a light-transmitting or opaque / reflecting material. The transparent material is, for example, glass, quartz, organic polymer, or other applicable materials, and the opaque / reflective material is, for example, wafer, ceramic, or other applicable materials.

Please refer to Figure 2. The optical film 110 is located on the first substrate 102 and the display medium layer 106 (eg, liquid crystal) on the upper and lower surfaces of the first substrate 102, respectively. The optical film 110 has a refractive power, so that the light (for example, the second reflected light RL2) can be deflected by a refractive angle θ ₂ ′, pass through the optical film 110, and exit the display device 100 with the refracted light RR. The refraction angle θ ₂ ′ is defined as the angle between the second reflected light RL2 and the refracted light RR, which can be between -30∘ and + 30∘. However, the present invention is not limited to this. In other embodiments, the optical film 110 may have both refractive power and scattering power. In detail, the optical film 110 can also disperse light (for example, refracted light RR) at a scattering angle δ. The scattering angle δ is defined as the angle at which the refracted light RR deviates from its original path (ie, the angle between the refracted light RR and the scattered light SL), which can be between -45∘ to + 45∘ and surround the refracted light RR, so that the original concentration The refracted light RR emitted at a point is dispersed to the peripheral area of the point (for example, the area where the scattered light SL surrounds the refracted light RR), thereby improving the reflectivity of the peripheral area. In other words, the viewing angle for viewing the display device 100 may be between θ ₂ -δ to θ ₂ + δ, and the light uniformity within the viewing angle range between θ ₂ -δ to θ ₂ + δ is improved. In a possible embodiment, in addition to the above-mentioned refractive or scattering capabilities, the optical film 110 may also have at least one of the following characteristics: allowing light to have a specific directivity, controlling the angle of light exit, and changing the optical path.

Please refer to Figure 2. An organic layer 112 and a pixel electrode 114 may be disposed between the second substrate 104 and the reflective layer 108. The organic layer 112 is disposed on the second substrate 104 and has a plurality of raised structures 112P. The raised structure 112P may be located on a part of the surface of the organic layer 112, but not limited thereto. In some embodiments, the raised structure 112P may also be located on the entire surface of the organic layer 112. In addition, the convex structure 112P is, for example, a symmetrical convex structure or an asymmetrical convex structure in the cross section shown in FIG. The shape of the convex structure 112P is, for example, a strip shape or a dot shape when viewed from the direction z (perpendicular to the second substrate 104). For example, in the cross section shown in FIG. 2, the raised structure 112P and the first plane F1 where it is located have a first base angle β1 and a second base angle β2 that are oppositely arranged, The substrate 104 is parallel. When the convex structure 112P is a point-like symmetrical convex structure, the first base angle β1 and the second base angle β2 are the same as each other and are symmetrically located around the center of the convex structure 112P to become a point-like symmetrical convex structure. When the convex structure 112P is a strip-shaped symmetric convex structure, the first base angle β1 and the second base angle β2 are the same as each other and the convex structure 112P extends along the direction y to become a strip-shaped symmetric convex structure.

Please refer to Figure 2. A pixel electrode 114 and a reflective layer 108 may be sequentially arranged on the organic layer 112, but the present invention is not limited thereto. In other embodiments, the reflective layer 108 can be replaced with the pixel electrode 114. More specifically, the pixel electrode 114, which is usually a transparent conductive material, can be changed to a pixel electrode of a conductive material that can reflect light, so that the pixel electrode 114 can be used as the reflective layer 108. In other words, in other possible embodiments, it is not necessary to provide the pixel electrode 114 and the reflective layer 108 separately.

In the embodiment of FIG. 2, the pixel electrode 114 covers the protrusion structure 112P of the organic layer 112 to form a plurality of protrusion structures 114P, and the reflective layer 108 covers the protrusion structure 114P of the pixel electrode 114 to form a plurality of protrusions From the structure 108P. Therefore, the convex structure 114P and the convex structure 108P respectively have a shape change corresponding to the convex structure 112P. Taking the raised structure 108P as an example, there is a line TL on the surface of the raised structure 108P, and the tangent line TL is tangent to the surface of the raised structure 108P at a point. It should be noted that, for clarity, the second plane F2 is depicted on the upper surface of the reflective layer 108 parallel to the second substrate 104. There is an included angle α between the tangent line TL and the second plane F2 and another included angle (not shown) opposite thereto, wherein the included angle α may have the same angle as the first base angle β1, and the other included angle (not shown) may It has the same angle as the second base angle β2, and the convex structure 108P has a shape change corresponding to the convex structure 112P. In this embodiment, in order to make the display device 100 suitable for viewing at a viewing angle θ ₂ , after selecting the viewing angle θ _{2 of the} viewing display device 100 and the optical film 110 to be used together, the angle α can be calculated according to the following formula to obtain an ideal Design value: α = (θ ₁ + θ ₂ '-θ ₂ ) / 2 where θ ₁ is the original angle of incidence of light (for example, incident light IL) toward the reflective layer 108, which means that the angle of incidence θ _{1 is} defined as the normal The angle between NL1 (perpendicular to the second substrate 104) and the incident light IL.

The following describes in detail the traveling path of light rays after the incident light IL (for example, ambient light) is irradiated to the reflective layer 108 having the convex structure 108P and after being irradiated to the flat reflective layer 108 with reference to FIG. 2.

When the incident light IL (for example, ambient light) is irradiated onto the flat reflective layer 108, according to the reflection rate, the reflection path is based on the normal NL1 (perpendicular to the second substrate 104) based on the path of the first reflected light RL1 reflection. When the incident light IL (for example, ambient light) is irradiated onto the reflective layer 108 with the convex structure 108P, according to the reflection rate, the reflection path will be based on the normal NL2 (perpendicular to the tangent line TL) and the second reflected light RL2 Path for reflection. In other words, when a part or all of the reflective layer 108 is formed with the convex structure 108P, the first reflected light RL1 can be changed to the second reflected light RL2 at an angle 2α. Then, the second reflected light RL2 can be deflected by the angle θ ₂ ′ through the optical film 110 having refractive power, and then exit the display device 100 with the refracted light RR. The display device 100 is suitable for viewing at a viewing angle θ ₂ .

FIG. 1 is a step diagram of a design method of a reflective layer according to an embodiment of the invention. According to the concept of the present invention, a design method of the reflective layer as shown in FIG. 1 can be provided.

Please refer to Figure 1 and Figure 2 at the same time. In step S100, the viewing angle θ _{2 for} viewing the display device 100 is first selected. Next, in step S102, an optical film 110 is provided on the first substrate 102, and the refraction angle of light (for example, the second reflected light RL2) passing through the optical film 110 is θ ₂ ′. After that, in step S104, the reflective layer 108 is formed with a plurality of convex structures 108P, the tangent line TL is tangent to the surface of the convex structure 108P, and there is an angle α between the tangent line TL and the second plane F2 where the reflective layer 108 is located , The angle α conforms to the following formula, so that the display device 100 can be viewed at the viewing angle θ ₂ : α = (θ ₁ + θ ₂ ′ -θ ₂ ) / 2 where θ ₁ is light (for example, incident light IL) that is incident on the reflective layer 108 The original angle of incidence. In this embodiment, in addition to forming the reflective layer 108 with a plurality of raised structures 108P, step S104 may also include the steps of forming the organic layer 112 and the pixel electrode 114, where the reflective layer 108, the pixel electrode 114 and For a detailed description of the organic layer 112, reference may be made to the foregoing embodiment, and no further description is provided here.

FIG. 3 is a schematic diagram of a display device according to an embodiment of a design method of a reflective layer according to the present invention, which includes incident light IL (for example, ambient light) after being irradiated on the reflective layer 108 having a convex structure 108P and on a flat The ray travel path behind the reflective layer 108. FIG. 4 is a graph showing the relationship between the viewing angle θ ₂ and the reflectance in FIG. 3.

Please refer to Figure 3 first. The basic architecture of the display device 200 is the same as the basic architecture of the display device 100. Unless otherwise stated, the specific description of the display device 200 can refer to the display device 100. In this embodiment, the viewing angle θ ₂ of the display device 200 is first selected to be 0∘ (that is, the line of sight of the eye is perpendicular to the display device 200), and then an optical film 110 is provided on the first substrate 102, in which light (eg, second reflection The refraction angle of the light RL2) passing through the optical film 110 is θ ₂ ′. After that, the angle α is calculated according to the formula α = (θ ₁ + θ ₂ ′ -θ ₂ ) / 2. In this embodiment, the included angle α is, for example, in the range of greater than 0∘ and less than 45∘, so that after the incident light IL is reflected by the reflective layer 108 having the convex structure 108P, the first reflected light RL1 can be changed by the included angle 2α to The second reflected light RL2, and the second reflected light RL2 may be deflected by the angle θ ₂ ′ when passing through the optical film 110 and exit the display device 200 with refracted light RR. In this embodiment, the path of the refracted light RR may be perpendicular to the display device 200, so the reflectance is improved at a position where the viewing angle θ ₂ is 0∘ (see FIG. 4). In detail, FIG. 4 shows that when the flat reflective layer 108 reflects, it has excellent reflectance at a position of, for example, 30∘, taking the normal NL3 as a reference, and the reflectance at a position where the selected viewing angle θ ₂ is 0∘ There is also an upward trend. In addition, in the present embodiment, the optical film 110 has, for example, a scattering ability so that light rays (for example, refracted light RR) can be dispersed at a scattering angle δ. Therefore, the reflectance in the viewing angle range of θ ₂ -δ to θ ₂ + δ can be increased together, so that uniform brightness can be obtained in the viewing angle range of θ ₂ -δ to θ ₂ + δ.

FIG. 5 is a schematic diagram of a display device according to still another embodiment of the design method of the reflective layer according to the present invention, which includes the incident light IL (for example, ambient light) after being irradiated to the reflective layer 108 having the convex structure 108P and irradiated to be flat The path of light travels behind the reflective layer 108. FIG. 6 is a relationship diagram between the viewing angle θ ₂ and the reflectance in FIG. 5.

Please refer to Figure 5 first. The basic architecture of the display device 300 is the same as the basic architecture of the display device 100. Unless otherwise stated, the specific description of the display device 300 may refer to the display device 100. In this embodiment, the viewing angle θ ₂ of the display device 300 is first selected to be -10∘, and then the optical film 110 is provided on the first substrate 102, wherein the light (for example, the second reflected light RL2) is refracted through the optical film 110 The angle is θ ₂ ′. After that, the angle α is calculated according to the formula α = (θ ₁ + θ ₂ ′ -θ ₂ ) / 2. In this embodiment, the included angle α is, for example, in the range of greater than or equal to 45∘ and less than 90∘, so that after the incident light IL is reflected by the reflective layer 108 having the convex structure 108P, the first light located on the side of the normal NL1 The reflected light RL1 changes to the second reflected light RL2 located on the other side of the normal NL1 at the included angle 2α, and the second reflected light RL2 can be deflected by the angle θ ₂ ′ when passing through the optical film 110, and emitted as the refracted light RR Display device 300. In this embodiment, the path of the refracted light RR is shifted by -10∘ compared to the normal NL3, so the reflectivity is improved at the position where the viewing angle θ ₂ is -10∘ (see FIG. 6). In detail, FIG. 6 shows that when the flat reflective layer 108 reflects, it has excellent reflectivity at a position of, for example, 30∘, based on the normal NL3, and reflects at a position where the selected viewing angle θ ₂ is -10∘ The rate also tends to rise. In addition, in the present embodiment, the optical film 110 has, for example, a scattering ability so that light rays (for example, refracted light RR) can be dispersed at a scattering angle δ. According to this, the reflectance in the viewing angle range of θ ₂ -δ to θ ₂ + δ can be increased together, so that uniform brightness can be obtained in the viewing angle range of θ ₂ -δ to θ ₂ + δ.

7 is a schematic diagram of a display device according to yet another embodiment of the design method of the reflective layer of the present invention, which includes incident light IL (for example, ambient light) irradiated to the reflective layer 108 having a convex structure 108P and irradiated to a flat The path of light travels behind the reflective layer 108. FIG. 8 is a relationship diagram between the viewing angle θ ₂ and the reflectance in FIG. 7.

Please refer to Figure 7 first. The basic architecture of the display device 400 is the same as the basic architecture of the display device 100. Unless otherwise stated, the specific description of the display device 400 may refer to the display device 100. In this embodiment, the viewing angle θ ₂ of the display device 400 is first selected to be 0∘ (that is, the line of sight of the eye is perpendicular to the display device 400), and then an optical film 110 is provided on the first substrate 102, in which light (eg, second reflection The refraction angle of the light RL2) passing through the optical film 110 is θ ₂ ′. After that, the angle α is calculated according to the formula α = (θ ₁ + θ ₂ ′ -θ ₂ ) / 2. In this embodiment, there is an included angle α between the tangent line TL and the second plane F2 and another included angle (not shown) opposite thereto, wherein the angle between the included angle α and another included angle (not shown) is different, making the convex The raised structure 108P may be an asymmetric raised structure. After the incident light IL is reflected by the reflective layer 108 having the convex structure 108P, the first reflected light RL1 can be changed to the second reflected light RL2 at an angle 2α, and the second reflected light RL2 can be deflected when passing through the optical film 110 At an angle of θ ₂ ′, the display device 400 is emitted with refracted light RR. In this embodiment, the path of the refracted light RR may be perpendicular to the display device 400, so the reflectance is improved at a position where the viewing angle θ ₂ is 0∘ (see FIG. 8). In detail, FIG. 8 shows that when the flat reflective layer 108 reflects, it has excellent reflectance at a position of, for example, 30∘, taking the normal NL3 as a reference, and the reflectance at a position where the selected viewing angle θ ₂ is 0∘ There is also an upward trend. Further, in the present embodiment, for example, an optical film 110 having scattering ability, so that the light (e.g. refractive RR) can be dispersed in a scattering angle [delta] Accordingly, together can improve the viewing angle + δ to θ ₂ θ ₂ -δ Reflectivity in the range, so that uniform brightness is obtained in the viewing angle range of θ ₂ -δ to θ ₂ + δ. It is worth noting that, in this embodiment, the convex structure 108P is an asymmetric convex structure, so the reflective layer 108 can exert the maximum benefit and obtain a higher reflectivity in a limited space. Hereinafter, it will be further described with reference to FIGS. 3 and 7. In a raised structure 108P of FIG. 3, the left area and the right area of the apex of the raised structure 108P are substantially the same; in a raised structure 108P of FIG. 7, the left area of the apex of the raised structure 108P is greater than Right area. When the area on the left side of the apex of the convex structure 108P in FIGS. 3 and 7 is the same, since the area on the right side of the apex of the convex structure 108P in FIG. 7 is reduced, more convex structures 108P can be provided, thereby increasing the number of The reflected light RL1 is changed to the amount of the second reflected light RL2 at an angle 2α, and a higher reflectance is obtained. The results can be shown in Figures 4 and 8. The reflectance at the position where the viewing angle θ ₂ is 0∘ selected in FIG. 8 is higher than the reflectance at the position where the viewing angle θ ₂ is 0∘ selected in FIG. 4.

In summary, the reflective layer according to an embodiment of the present invention is formed with a convex structure that meets the above formula, so that incident light can be reflected through the convex structure to a selected viewing angle. In addition, through the optical film, the reflectivity of the periphery of the selected viewing angle can be increased. As a result, the problems of limited viewing angle and low display quality of the transflective display device or the reflective display device described in the prior art can be improved.

Although the present invention has been disclosed as above with examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be subject to the scope defined in the appended patent application.

100, 200, 300, 400: display device 102: first substrate 104: second substrate 106: display medium layer 108: reflective layer 108P, 112P, 114P: raised structure 110: optical film 112: organic layer 114: pixel Electrode F1: first plane F2: second plane IL: incident light NL1, NL2, NL3: normal RL1: first reflected light RL2: second reflected light RR: refracted light S100, S102, S104: step SL: scattered light TL: tangent y, z: direction α: angle β1: a first base angle β2: a second base angle θ _1: an original incidence angle θ _2: angle θ ₂ ': angle of refraction δ: scattering angle

FIG. 1 is a step diagram of a design method of a reflective layer according to an embodiment of the invention. 2 is a schematic diagram of a display device according to an embodiment of the invention. 3 is a schematic diagram of a display device according to an embodiment of the design method of the reflective layer of the present invention. FIG. 4 is a graph showing the relationship between the viewing angle θ ₂ and the reflectance in FIG. 3. 5 is a schematic diagram of a display device according to still another embodiment of the design method of the reflective layer of the present invention. FIG. 6 is a relationship diagram between the viewing angle θ ₂ and the reflectance in FIG. 5. 7 is a schematic diagram of a display device according to still another embodiment of the design method of the reflective layer of the present invention. FIG. 8 is a relationship diagram between the viewing angle θ ₂ and the reflectance in FIG. 7.

Claims (9)

A design method of a reflective layer is suitable for a display device. The display device includes a first substrate, a display medium layer, a reflective layer and a second substrate. The design method of the reflective layer includes: selecting to view the display device Viewing angle θ ₂ ; an optical film is provided on the first substrate, and the angle of refraction of light passing through the optical film is θ ₂ ′; and the reflective layer is formed with a plurality of convex structures, the convex structures forming a On a continuous arc surface, all lines are tangent to the surface of the convex structure, and there is an angle α between the tangent line and the plane where the reflective layer is located. The angle α conforms to the following formula, so that the display device can view the viewing angle θ ₂ Viewing: α = (θ ₁ + θ ₂ '-θ ₂ ) / 2 where θ ₁ is the original angle of incidence of the light toward the reflective layer, and the included angle α is in the range greater than 0 ° and less than 90 °. The design method of the reflective layer as described in item 1 of the patent application scope, wherein θ _{2 is} between -60 ° and + 60 °. The design method of the reflective layer as described in item 1 of the patent application scope, wherein θ ₂ ′ is between -30 ° and + 30 °. The design method of the reflective layer as described in item 1 of the patent application range, wherein the scattering angle of light passing through the optical film is δ, so that the viewing angle for viewing the display device is between θ ₂ -δ to θ ₂ + δ , Where δ is between -45 ° and + 45 °. Between a display medium layer, located between the first substrate and the second substrate; a first substrate; a second substrate opposed to the first substrate: a display device adapted perspective view θ _2, the display device comprising An optical film is located on the first substrate, and the angle of refraction of light passing through the optical film is θ ₂ ′; and a reflective layer is located between the second substrate and the display medium layer and has a plurality of protrusions Structure, the convex structures have a continuous arc surface, and all lines are tangent to the surface of the convex structure, and an angle α between the tangent line and the plane where the reflective layer is located, the angle α conforms to the following formula, to Enable the display device to be viewed at the viewing angle θ ₂ : α = (θ ₁ + θ ₂ ′ -θ ₂ ) / 2 where θ ₁ is the original angle of incidence of light rays toward the reflective layer, and the included angle α is greater than 0 ° and less than 90 °. The display device as described in item 5 of the patent application scope, wherein θ _{2 is} between -60 ° and + 60 °. The display device as described in item 5 of the patent application scope, wherein θ ₂ ′ is between -30 ° and + 30 °. The display device as described in item 5 of the patent application range, wherein the scattering angle of light passing through the optical film is δ, so that the viewing angle for viewing the display device is between θ ₂ -δ to θ ₂ + δ, where δ Between -45 ° and + 45 °. The display device as described in item 5 of the patent application range, wherein the raised structures are symmetric or asymmetric raised structures.