Display device

Abstract

A display device includes a backlight unit, a viewing angle shifting film, and a lower polarizing film. The viewing angle offset film is disposed on the backlight unit. The lower polarizing film is disposed on the viewing angle offset film. The viewing angle offset film has a stretching direction, a first included angle is formed between the stretching direction and the first direction, the lower polarizing film comprises a first optical penetration axis, a second included angle is formed between the first optical penetration axis and the first direction, and the second included angle is smaller than or equal to the first included angle.

Description

Technical Field

[0001] This invention relates to a display device. Background Technology

[0002] In current display devices, different optical film layers are set for different display functions. However, the setting of optical film layers often leads to phase delay and brightness reduction when the backlight module emits light due to the different optical film layers. Therefore, it is very important to effectively reduce the phase delay of the display light and improve the brightness while realizing different functions of the display device. Summary of the Invention

[0003] The present invention provides a display device having high brightness and low phase delay.

[0004] The display device of the present invention includes a backlight unit, a viewing angle shift film, and a lower polarizing film. The viewing angle shift film is disposed on the backlight unit. The lower polarizing film is disposed on the viewing angle shift film. The viewing angle shift film has a stretching direction, and the stretching direction has a first angle with a first direction. The lower polarizing film includes a first optical transmission axis, and the first optical transmission axis has a second angle with the first direction, the second angle being less than or equal to the first angle.

[0005] Based on the above, the stretching direction of the viewing angle shift film has a first angle with the first direction, and the first optical transmission axis of the lower polarizing film has a second angle with the first direction, and the second angle is less than or equal to the first angle. In this way, the display device can have higher brightness and lower phase delay. Attached Figure Description

[0006] Figure 1A This is an exploded view of a display device according to an embodiment of the present invention.

[0007] Figure 1B This is an optical schematic diagram of a viewing angle shifting film in a display device.

[0008] Figure 1C This is a schematic diagram of the lower polarizing film in a display device.

[0009] Figure 1D This is a schematic diagram of the privacy-protecting reflective polarizing film in a display device.

[0010] Figure 1E This is a schematic diagram of the optical properties of the viewing angle dimming film in a display device.

[0011] Figure 2 This is a cross-sectional schematic diagram of a display device according to another embodiment of the present invention.

[0012] Figure 3 This is a cross-sectional schematic diagram of a display device according to another embodiment of the present invention.

[0013] In the attached figures, the following labels are used:

[0014] 100A, 100B, 100C: Display devices

[0015] 110: Backlight unit

[0016] 120: Viewpoint offset film

[0017] 122: Viewpoint Offset Structure Layer

[0018] 130: Anti-spy reflective polarizing film

[0019] 140: View Dimmer

[0020] 150: Lower polarizing film

[0021] 160: Panel

[0022] 170: Prism layer

[0023] 180: Optical adhesive layer

[0024] A1: First optical transmission axis

[0025] A2: Second optical transmission axis

[0026] B-B': Reference axis

[0027] D1: First Direction

[0028] D2: Second Direction

[0029] D3: Third direction

[0030] MD: Tension direction

[0031] P A :spacing Detailed Implementation

[0032] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0033] Figure 1A This is an exploded view of a display device according to an embodiment of the present invention. Figure 1B This is an optical schematic diagram of a viewing angle shifting film in a display device. Figure 1C This is a schematic diagram of the lower polarizing film in a display device. Figure 1D This is a schematic diagram of the anti-peeping reflective polarizing film in a display device. Please also refer to... Figures 1A to 1E .

[0034] A display device 100A includes a backlight unit 110, a viewing angle shift film 120, and a lower polarizing film 150. The viewing angle shift film 120 is disposed on the backlight unit 110, and the lower polarizing film 150 is disposed on the viewing angle shift film 120. The viewing angle shift film has a stretching direction MD, and the stretching direction MD has a first angle θ1 with a first direction. The lower polarizing film 150 includes a first optical transmission axis A1, and the first optical transmission axis A1 has a second angle θ2 with the first direction MD, wherein the second angle θ2 is less than or equal to the first angle θ1.

[0035] The first included angle θ1 falls within the range of 0 degrees or more and 135 degrees or less. The second included angle θ2 falls within the range of 0 degrees or more and 45 degrees or less.

[0036] The backlight unit 110 may sequentially include a frame, a diffuser plate, a light-emitting plate, a reflective sheet, and a baffle. The light-emitting plate may include, for example, an organic light-emitting diode (OLED), a miniLED, a microLED, or a quantum dot (QD, such as QLED or QDLED), fluorescent, phosphorescent, or other suitable materials, and these materials can be arranged and combined arbitrarily, but are not limited thereto. The frame, diffuser plate, and baffle are disposed around the light-emitting plate, and the frame, diffuser plate, and baffle may include a multi-layer structure, such as a two-layer structure, but the invention is not limited thereto; a single-layer structure is also possible.

[0037] The display device 100A also includes a prism layer 170 and a privacy reflective polarizing film 130. The prism layer 170 is disposed between the backlight unit 110 and the privacy reflective polarizing film 130. The privacy reflective polarizing film 130 includes a second optical transmission axis A2. The second optical transmission axis A2 and the first direction D1 have a third angle θ3. The range of the third angle θ3 is greater than or equal to 45 degrees and less than or equal to 135 degrees.

[0038] A better optical transmission efficiency can be obtained when the first optical transmission axis A1 is parallel to the second optical transmission axis A2 (for example, the angle between the first optical transmission axis A1 and the second optical transmission axis A2 falls within the range of greater than 179 degrees and less than 181 degrees). The display device can also obtain the best optical transmission efficiency when the first included angle θ1 is perpendicular to the first optical transmission axis A1 or the second optical transmission axis A2 (for example, the angle between the first included angle θ1 and the first optical transmission axis A1 or the second optical transmission axis A2 falls within the range of greater than 89 degrees and less than 91 degrees) or parallel to it (for example, the angle between the first included angle θ1 and the first optical transmission axis A1 or the second optical transmission axis A2 falls within the range of greater than 179 degrees and less than 181 degrees).

[0039] The display device 100A also includes a viewing angle dimmer 140 disposed between the lower polarizing film 150 and the panel 160. The viewing angle dimmer can control the brightness of the light L emitted by the backlight unit 110 to adapt to different environmental requirements. The material of the viewing angle shifting film 120 may be, for example, polyethylene terephthalate (PET).

[0040] The display device 100A also includes a panel 160, which may be made of, for example, glass, a polymer, or a transparent or translucent material that allows light to pass through, but is not limited thereto.

[0041] In this invention, the direction of the penetration axis is defined as the direction in which electromagnetic waves (e.g., light waves) are allowed to pass through. When two different diaphragms have the same penetration axis direction, these two diaphragms allow electromagnetic waves with the same polarization direction to pass through. When the penetration axes of the two diaphragms are at a 90-degree angle, only one diaphragm is allowed to pass through. When the angle between the penetration axes of the two diaphragms is less than or greater than 90 degrees, electromagnetic waves can partially penetrate both diaphragms. The stretching direction is defined as the machine stretching direction (MD), and the other direction relative to the machine stretching direction is the transverse direction (TD). The machine stretching direction is perpendicular to the transverse direction.

[0042] Please refer to Figures 1B to 1E The reference axis B-B' is parallel to the first direction D1 (i.e., the x-axis direction), and the angle between the stretching direction or the penetration axis and the first direction D1 is the angle between the stretching direction or the penetration axis and the first direction D1.

[0043] When the stretching direction MD of the viewing angle shifting film 120 is parallel to the first direction D1, the viewing angle shifting film has a first refractive index n1. When the stretching direction MD of the viewing angle shifting film 120 is perpendicular to the first direction D1, the viewing angle shifting film has a second refractive index n2. The first refractive index n1 and the second refractive index n2 are different. The difference between the first refractive index n1 and the second refractive index n2 is, for example, less than or equal to 0.004, but is not limited thereto. In some embodiments, the difference between the first refractive index n1 and the second refractive index n2 may also be greater than 0.004. The first refractive index n1 is, for example, 1.64, and the second refractive index n2 is, for example, 1.636.

[0044] Figure 1E This is a graph showing the relationship between the brightness of a display device and the viewing angle.

[0045] Depend on Figure 1EAs shown at point A, when the difference between the first included angle θ1 and the second included angle θ2 is 45 degrees, the display device 100A has approximately 50% brightness. As shown at point B, when the values ​​of the first included angle θ1 and the second included angle θ2 are equal (for example, both the first included angle θ1 and the second included angle θ2 are 45 degrees), the display device 100A has approximately 76% brightness. Therefore, point A exhibits greater interference and phase delay. In contrast, point B produces less phase difference, and thus its phase delay is significantly smaller than that of point A.

[0046] Depend on Figure 1E As can be seen from point C, when the first included angle θ1 is greater than the value of the second included angle θ2 by 45 degrees (for example, the value of the first included angle θ1 is 90 degrees and the value of the second included angle θ2 is 45 degrees), the display device 100A has a brightness of about 45%. As can be seen from point D, when the first included angle θ1 is greater than the value of the second included angle θ2 by 90 degrees (for example, the value of the first included angle θ1 is 135 degrees and the value of the second included angle θ2 is 45 degrees), the display device 100A has a brightness of about 82%. Therefore, point C has greater interference and phase delay. In contrast, point D produces less phase difference, and the phase delay at point D is significantly smaller than that at point C.

[0047] Figure 2 This is a cross-sectional schematic diagram of a display device according to another embodiment of the present invention.

[0048] The display device 100B also includes a venetian blind layer 132 and a viewing angle shifting structure layer 122. The venetian blind layer 132 is disposed between the viewing angle shifting structure layer 122 and the privacy-proof reflective polarizing film 130. The viewing angle shifting structure layer 122 includes multiple asymmetric structures, and each of the multiple asymmetric structures has a spacing P between it. A Spacing P A The range falls within 24 micrometers or less. Privacy-protected reflective polarizing films, such as dual brightness enhancement films (DBEF), primarily function to recover and reuse unused polarized light from the backlight unit through optical interference, thereby improving the overall brightness and visual quality of the display device and reducing energy consumption. In some embodiments, privacy-protected reflective polarizing films may be, for example, advanced light control films (ALCF), utilizing a venetian blind layer to control the light emission angle.

[0049] The venetian blind layer 132 includes a light-absorbing area and a light-transmitting area. The material of the light-absorbing area may include, for example, black block resin, while the material of the light-transmitting area may include, for example, transparent resin. This allows for control over light absorption and transmission. The viewing angle shifting structure layer 122 may be made of, for example, acrylic resin. The viewing angle shifting film 120 may be made of, for example, polyester fiber.

[0050] Figure 3 This is a cross-sectional schematic diagram of a display device according to another embodiment of the present invention.

[0051] The difference between display device 100C and display device 100B is that display device 100C also includes an optical adhesive layer 180, which is disposed between the viewing angle offset structure layer 122 and the venetian blind layer 132. The optical adhesive layer 180 may be, for example, a pressure-sensitive adhesive (PSA), used for bonding films to each other, and has high light transmittance.

[0052] In summary, the stretching direction of the viewing angle shift film of the present invention has a first angle with the first direction, and the first optical transmission axis of the lower polarizing film has a second angle with the first direction, and the second angle is less than or equal to the first angle. Thus, the display device can have higher brightness and lower phase delay.

[0053] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A display device, characterized in that, include: Backlight unit; A viewing angle offset film is disposed on the backlight unit; as well as The lower polarizing film is disposed on the viewing angle shifting film. The viewing angle shifting film has a stretching direction, and the stretching direction has a first angle with a first direction. The down-polarizing film includes a first optical transmission axis, and the first optical transmission axis has a second angle with the first direction, and the second angle is less than or equal to the first angle.

2. The display device as claimed in claim 1, characterized in that, The first included angle falls within the range of 0 degrees or more and 135 degrees or less.

3. The display device as claimed in claim 1, characterized in that, The range of the second included angle is greater than or equal to 0 degrees and less than or equal to 135 degrees.

4. The display device as claimed in claim 1, characterized in that, It also includes a prism layer and a privacy reflective polarizing film. The prism layer is disposed between the backlight unit and the privacy reflective polarizing film. The privacy reflective polarizing film includes a second optical transmission axis, and the second optical transmission axis has a third angle with the first direction. The range of the third angle is greater than or equal to 0 degrees and less than or equal to 135 degrees.

5. The display device as claimed in claim 1, characterized in that, When the stretching direction is parallel to the first direction, the viewing angle shifting film has a first refractive index; when the stretching direction is perpendicular to the first direction, the viewing angle shifting film has a second refractive index, and the first refractive index is different from the second refractive index.

6. The display device as claimed in claim 5, characterized in that, The difference between the first refractive index and the second refractive index is less than or equal to 0.

004.

7. The display device as claimed in claim 1, characterized in that, The view offset film further includes a view offset structure layer, which comprises multiple asymmetric structures, each of which has a spacing between it, and the spacing ranges from less than or equal to 24 micrometers.

8. The display device as claimed in claim 4, characterized in that, The angle between the first optical transmission axis and the second optical transmission axis falls within the range of greater than 179 degrees and less than 181 degrees.

9. The display device as claimed in claim 8, characterized in that, The angle between the first included angle and the first optical transmission axis or the second optical transmission axis falls within the range of greater than 89 degrees and less than 91 degrees.

10. The display device as claimed in claim 8, characterized in that, The angle between the first included angle and the first optical transmission axis or the second optical transmission axis falls within the range of greater than 179 degrees and less than 181 degrees.

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