Display device

Abstract

A display device comprises a backlight module, a half-wave plate, a visual angle modulation layer and a display panel which are stacked in sequence. The display panel comprises a first polaroid, a pixel layer and a second polaroid which are stacked in sequence. The first polaroid is located between the visual angle modulation layer and the pixel layer. The backlight module comprises a prismatic lens, and the prismatic lens comprises a plurality of prism structures arranged in the first direction. The half-wave plate is provided with a slow axis which is parallel to the second direction, and the first direction and the second direction are not parallel and not perpendicular.

Description

Technical Field

[0001] The present invention relates to an optical device, and in particular to a display device. Background Art

[0002] The backlight source of the display panel has a considerable difference between the intensity of vertical polarization and the intensity of horizontal polarization due to the structure of the film inside it. The former can be 22% stronger than the latter. In addition, the viewing angle modulation layer of the display panel is selective for the polarization direction, has a viewing angle modulation function for horizontal polarization, and has almost no viewing angle modulation function for vertical polarization. Summary of the invention

[0003] The invention provides a display device with high viewing angle modulation efficiency and high brightness.

[0004] According to one embodiment of the present invention, a display device is provided, comprising a backlight module, a half-wave plate, a viewing angle modulation layer and a display panel stacked in sequence. The display panel comprises a first polarizer, a pixel layer and a second polarizer stacked in sequence. The first polarizer is located between the viewing angle modulation layer and the pixel layer. The backlight module comprises a prism sheet, which comprises a plurality of prism structures arranged along a first direction. The half-wave plate has a slow axis, which is parallel to a second direction, and the first direction is not parallel to and not perpendicular to the second direction.

[0005] According to one embodiment of the present invention, a display device is provided, comprising a backlight module, a half-wave plate, a viewing angle modulation layer, a first polarizer, a pixel layer and a second polarizer which are stacked in sequence. The first polarizer has a transmission axis which is parallel to a first direction. The light provided by the backlight module has a first intensity and a second intensity before entering the half-wave plate. The first intensity is the intensity of the first part of the light, and the second intensity is the intensity of the second part of the light. The polarization direction of the first part of the light is parallel to the first direction, the polarization direction of the second part of the light is parallel to the second direction, and the second direction is perpendicular to the first direction. The ratio of the second intensity to the first intensity falls within the range of 1.23 to 2.34. The half-wave plate has a slow axis which is parallel to a third direction, and the first direction is not parallel to and not perpendicular to the third direction.

[0006] Based on the above, the display device provided by the embodiment of the present invention uses a half-wave plate to convert the polarization state of the backlight source to adapt to the viewing angle modulation layer, thereby improving the modulation efficiency of the viewing angle modulation layer and effectively improving the brightness of the display device.

[0007] In order to make the above features and advantages of the present invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1AA schematic diagram showing a display device according to some embodiments of the present invention is shown, Figure 1B According to an embodiment of the present invention, Figure 1A A schematic diagram of a viewing angle modulation layer in a display device is shown.

[0009] Figure 2 Schematic diagram showing a display device according to some embodiments of the present invention.

[0010] Figure 3 Schematic diagram showing a display device according to some embodiments of the present invention.

[0011] Description of reference numerals:

[0012] 1, 2, 3: Display device

[0013] 100: Half-wave plate

[0014] 200: Backlight module

[0015] 201: Prism

[0016] 201P: Prism structure

[0017] 202: Area light source

[0018] 300: Perspective Modulation Layer

[0019] 370: Liquid crystal layer

[0020] 372: Liquid crystal molecules

[0021] 400: Display panel

[0022] 410: Pixel layer

[0023] 440: Polarizer

[0024] 450: Polarizer

[0025] 500: Privacy film

[0026] 501: light-transmitting structure

[0027] 502: Light blocking structure DETAILED DESCRIPTION

[0028] Reference Figure 1A as well as Figure 1B , Figure 1A A schematic diagram showing a display device according to some embodiments of the present invention is shown, Figure 1B According to an embodiment of the present invention, Figure 1A A schematic diagram of a viewing angle modulation layer in a display device is shown.

[0029] The display device 1 includes a backlight module 200 , a half-wave plate 100 , a viewing angle modulation layer 300 , and a display panel 400 which are sequentially stacked along a Z direction.

[0030] The display panel 400 includes a polarizer 440, a pixel layer 410, and a polarizer 450 stacked in sequence, wherein the absorption axis of the polarizer 440 is parallel to the Y direction and the transmission axis is parallel to the X direction, the absorption axis of the polarizer 450 is parallel to the X direction and the transmission axis is parallel to the Y direction, wherein the X direction, the Y direction, and the Z direction are perpendicular to each other.

[0031] The viewing angle modulation layer 300 includes a liquid crystal layer 370, and the liquid crystal layer 370 includes liquid crystal molecules 372. Anchoring energy can be provided by an alignment film (not shown), and the direction of each liquid crystal molecule 372 can be controlled by an electrode layer (not shown) to control the viewing angle of the display device 1.

[0032] The backlight module 200 includes a prism sheet 201 and a surface light source 202. The prism sheet 201 includes a plurality of prism structures 201P, and the prism sheet 201 may be, for example, an inverse prism, but is not limited thereto. The prism structures 201P are arranged in sequence along the Y direction, and each prism structure 201P extends along the X direction. The cross-sectional schematic diagram of the prism sheet 201 on the YZ plane has a sawtooth shape. The surface light source 202 may include a plurality of light-emitting diodes, a light guide plate, an optical film and other components, and may be an edge-entry light source as shown in FIG. 1, but the present invention is not limited thereto.

[0033] It should be noted that, due to the directional structure of the prism sheet 201, the light from the surface light source 202 and penetrating the prism sheet 201 has an uneven electric field. Specifically, the electric field of the light from the backlight module 200 in the Y direction will be stronger than the electric field in the X direction, that is, the component of its polarization state in the Y direction will be greater than the component in the X direction. In other words, in the light from the backlight module 200, the intensity of the linear polarization in the Y direction is significantly greater than the intensity of the linear polarization in the X direction. In some embodiments, in the light from the backlight module 200, before it enters the half-wave plate 100, the ratio of the intensity of the linear polarization in the Y direction to the intensity of the linear polarization in the X direction falls between 1.23 and 2.34, but is not limited thereto. Accordingly, the display device 1 provided in this embodiment is provided with a half-wave plate 100, wherein the slow axis of the half-wave plate 100 is configured to be neither parallel to the X direction nor perpendicular to the X direction, so as to change the polarization state of the light from the backlight module 200, so that the changed polarization state can be adapted to the viewing angle modulation layer 300 and the polarizer 440, thereby improving the brightness of the display device 1. In one embodiment, the display device 1 provided with the half-wave plate 100 has a brightness improved by 12% compared with a display device according to a comparative example in which the half-wave plate 100 is not provided.

[0034] Specifically, in one embodiment, the electrode layer (not shown) of the viewing angle modulation layer 300 includes a plurality of electrodes arranged in sequence along the X direction and electrically insulated from each other, and each electrode has a strip shape extending along the Y direction. Therefore, when the liquid crystal molecules 372 in the liquid crystal layer 370 are driven by the electric field through the electrodes, the liquid crystal molecules 372 in the liquid crystal layer 370 can be as follows: Figure 1B Arranged as shown. The long axis of each liquid crystal molecule 372 is parallel to the XZ plane, and the long axes of multiple liquid crystal molecules 372 are inclined relative to the Z direction. Under such conditions, the viewing angle modulation layer 300 has a viewing angle modulation function for linear polarization of the electric field in the X direction, and has almost no viewing angle modulation function for linear polarization of the electric field in the Y direction. Therefore, in this embodiment, the slow axis of the half-wave plate 100 can be configured to have an angle of 45 degrees (or 225 degrees) with the X direction and an angle of 45 degrees (or 135 degrees) with the Y direction, so as to convert the Y-direction linear polarization in the light from the backlight module 200 into the X-direction linear polarization, so as to optimize the viewing angle modulation efficiency of the viewing angle modulation layer 300 and improve the transmittance of the polarizer 440.

[0035] In one embodiment, the display device 1 has only one prism sheet 201 having a prism structure 201P, and the display device 1 does not have other prism sheets having a prism structure 201P. Under such circumstances, the above-mentioned electric field non-uniformity is obviously present in the light from the backlight module 200. Therefore, by configuring the slow axis of the half-wave plate 100 to have an angle of 45 degrees (or 225 degrees) with the X direction and an angle of 45 degrees (or 135 degrees) with the Y direction, the Y-direction linear polarization with a larger intensity can be converted into the X-direction linear polarization. In other words, before the light enters the viewing angle modulation layer 300, its X-direction electric field intensity is greater than the electric field intensity in other directions, thereby maximizing the viewing angle modulation efficiency of the viewing angle modulation layer 300 and improving the transmittance of the polarizer 440.

[0036] In order to fully illustrate the various embodiments of the present invention, other embodiments of the present invention will be described below. It must be noted that the following embodiments use the component numbers and some contents of the previous embodiments, wherein the same numbers are used to represent the same or similar components, and the description of the same technical contents is omitted. For the description of the omitted parts, please refer to the previous embodiments, and the following embodiments will not be repeated.

[0037] Reference Figure 2 , which shows a schematic diagram of a display device according to some embodiments of the present invention.

[0038] The display device 2 includes a backlight module 200 , a privacy film 500 , a half-wave plate 100 , a viewing angle modulation layer 300 , and a display panel 400 which are sequentially stacked along the Z direction.

[0039] The display device 2 of this embodiment is different from the display device 1 in that a privacy film 500 is disposed in the display device 2, wherein the privacy film 500 is located between the backlight module 200 and the half-wave plate 100 to provide a privacy protection function. The privacy film 500 includes a plurality of light-blocking structures 502 arranged in sequence along the X direction and extending in the Y direction, and a light-transmitting structure 501 between the light-blocking structures 502, wherein each light-blocking structure 502 may be a columnar structure extending in the Y direction.

[0040] The prism sheet 201 in the display device 2 has the same structure as the prism sheet 201 in the display device 1. In this configuration, since the structure of the prism sheet 201 is directional and the structure of the privacy film 500 is directional, the light from the surface light source 202 and sequentially passing through the prism sheet 201 and the privacy film 500 has an uneven electric field, and the intensity of the linear polarization in the Y direction is significantly greater than the intensity of the linear polarization in the X direction.

[0041] The display device 2 provided in this embodiment is configured with a half-wave plate 100, wherein the slow axis of the half-wave plate 100 is configured to be neither parallel to the X direction nor perpendicular to the X direction, so as to change the polarization state of light from the backlight module 200 and the privacy film 500, so that the changed polarization state can be adapted to the viewing angle modulation layer 300 and the polarizer 440, and improve the brightness of the display device 2.

[0042] In one embodiment, the slow axis of the half-wave plate 100 can be configured to have an angle of 45 degrees (or 225 degrees) with the X direction and an angle of 45 degrees (or 135 degrees) with the Y direction, so as to convert the Y-direction linear polarization in the light from the backlight module 200 and the privacy film 500 into the X-direction linear polarization, so as to optimize the viewing angle modulation efficiency of the viewing angle modulation layer 300.

[0043] It should also be noted that the display device 2 of this embodiment further has a light collimation function compared to the display device 1 without the privacy film 500. The display device 2 has an improved privacy film function compared to the display device 1.

[0044] In one embodiment, the privacy film 500 in the display device 2 may be bonded to the half-wave plate 100 to avoid interface reflection between the privacy film 500 and the half-wave plate 100 , so as to further optimize the optical performance of the display device 2 .

[0045] According to some embodiments of the present invention, the positions of the privacy film 500 and the half-wave plate 100 in the display device 2 may be interchanged to form a display device 2 as follows: Figure 3The display device 3 shown. In the display device 3, the privacy film 500 is arranged between the half-wave plate 100 and the viewing angle modulation layer 300. By providing the privacy film 500, the display device 3 can be implemented as a privacy display device. By providing the half-wave plate 100, the optical performance of the display device 3 is good. In one embodiment, the privacy film 500 in the display device 3 can be bonded to the half-wave plate 100 to avoid interface reflection between the privacy film 500 and the half-wave plate 100, so as to further optimize the optical performance of the display device 3.

[0046] In summary, the display device provided by the embodiment of the present invention utilizes a half-wave plate to convert the polarization state of the backlight source to adapt to the viewing angle modulation layer, thereby improving the modulation efficiency of the viewing angle modulation layer and effectively improving the brightness of the display device.

Claims

1. A display device, comprising a backlight module, a half-wave plate, a viewing angle modulation layer and a display panel stacked in sequence, wherein The display panel includes a first polarizer, a pixel layer, and a second polarizer which are sequentially stacked, wherein the first polarizer is located between the viewing angle modulation layer and the pixel layer. The backlight module includes a prism sheet, wherein the prism sheet includes a plurality of prism structures arranged along a first direction, and The half-wave plate has a slow axis, the slow axis is parallel to a second direction, and the first direction is not parallel to and is not perpendicular to the second direction. 2 . The display device as claimed in claim 1 , wherein each of the prism structures extends toward a third direction, and the third direction is perpendicular to the first direction. The display device as claimed in claim 1 , wherein a transmission axis of the first polarizer is perpendicular to the first direction. The display device according to claim 1 , wherein the angle between the first direction and the second direction is 45 degrees or 135 degrees. The display device as claimed in claim 1 , wherein the display device includes only one film having the prism structure. The display device as claimed in claim 1 , wherein the prism sheet is an inverse prism sheet.

7. The display device as claimed in claim 2, further comprising a privacy film disposed between the backlight module and the viewing angle modulation layer, the privacy film comprising a plurality of light-blocking structures arranged along a third direction and extending toward the first direction.

8. The display device according to claim 7, wherein the privacy film is bonded to the half-wave plate. 9 . The display device as claimed in claim 7 , wherein the privacy film is disposed between the half-wave plate and the viewing angle modulation layer. 10 . The display device as claimed in claim 7 , wherein the privacy film is disposed between the half-wave plate and the backlight module. The display device as claimed in claim 1 , wherein the viewing angle modulation layer comprises liquid crystal molecules.

12. A display device, comprising a backlight module, a half-wave plate, a viewing angle modulation layer, a first polarizer, a pixel layer and a second polarizer stacked in sequence, wherein The first polarizer has a transmission axis, and the transmission axis is parallel to the first direction. The light provided by the backlight module has a first intensity and a second intensity before entering the half-wave plate, the first intensity is the intensity of the first part of the light, the second intensity is the intensity of the second part of the light, the polarization direction of the first part of the light is parallel to the first direction, the polarization direction of the second part of the light is parallel to the second direction, the second direction is perpendicular to the first direction, and the ratio of the second intensity to the first intensity falls within the range of 1.23 to 2.34, and The half-wave plate has a slow axis, the slow axis is parallel to a third direction, and the first direction is not parallel to and not perpendicular to the third direction. 13 . The display device according to claim 12 , wherein the backlight module comprises a prism sheet, the prism sheet comprises a plurality of prism structures arranged along the second direction, and each of the prism structures extends toward the first direction. 14 . The display device as claimed in claim 13 , wherein the display device includes only one film having the prism structure. The display device as claimed in claim 13 , wherein the prism sheet is an inverse prism sheet. 16 . The display device according to claim 12 , wherein an angle between the first direction and the third direction is 45 degrees or 225 degrees. 17 . The display device as claimed in claim 13 , further comprising a privacy film disposed between the backlight module and the viewing angle modulation layer, the privacy film comprising a plurality of light blocking structures arranged along a first direction and extending toward the second direction.

18. The display device of claim 17, wherein the privacy film is bonded to the half-wave plate. 19 . The display device as claimed in claim 17 , wherein the privacy film is disposed between the half-wave plate and the viewing angle modulation layer. 20 . The display device as claimed in claim 17 , wherein the privacy film is disposed between the half-wave plate and the backlight module.

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