CN113219659B

CN113219659B - Display device

Info

Publication number: CN113219659B
Application number: CN202110388770.8A
Authority: CN
Inventors: 罗诚
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-08-15
Filing date: 2018-09-29
Publication date: 2022-07-29
Anticipated expiration: 2038-09-29
Also published as: CN113219659A; CN109164636B; CN109164636A; WO2020034658A1

Abstract

The embodiment of the application provides a display device, including backlight unit and display screen, backlight unit includes emitting diode LED and light guide plate, is provided with the light-emitting microstructure on the light guide plate, and the position that sets up of light-emitting microstructure is corresponding with the first pixel region position in the visual field of display screen, and LED's light passes through the light-emitting microstructure and reaches the first pixel region in visual field, has reduced the waste of light energy.

Description

Display device

The present application claims priority from the chinese patent application filed on 15/08/2018 under the name of "a method for VR display" with the chinese patent office, application No. 201810930320.5, the entire contents of which are incorporated herein by reference.

Technical Field

The present disclosure relates to the field of virtual reality, and in particular, to a Virtual Reality (VR) display method and a VR display apparatus.

Background

VR display devices began to move to the consumer market in 2016. The display in the VR display device is fixed to the head of the user, and two images are displayed to both eyes using two displays, respectively. The images in the two displays are driven by the display chips respectively, and have small difference, similar to binocular parallax. The display simulates the real world by creating an enlarged virtual image through the lens. When the head moves to the left, the display displays an animation moving from the left to the right, and changes of visual pictures seen by human eyes in the real world are simulated. However, in order to solve the problem that a conventional Liquid Crystal Display (LCD) displays a moving picture moving at a high speed may have serious smear, which may cause a user to feel dizzy and nausea, a fast response LCD (fast LCD) with a backlight black insertion technology is used.

The VR display device simulates human eyes, and after passing through the lenses, the eyes see a field of area (FoV), while the Active Area (AA) of the fast response liquid crystal display is generally square, so that the pixels in the AA cannot be seen in the field of view, as shown in fig. 1, which causes pixel waste and also causes waste of light energy of the backlight module for the fast response liquid crystal display.

Disclosure of Invention

The embodiment of the application provides a display device, and waste of light energy is reduced.

The application provides a display device, including backlight unit and display screen, backlight unit includes emitting diode LED and light guide plate, is provided with the light-emitting microstructure on the light guide plate, and the position that sets up of light-emitting microstructure is corresponding with the first pixel area position in the visual field of display screen, and LED's light passes through the light-emitting microstructure and reaches the first pixel area in visual field, has reduced the waste of light energy.

In one possible design, the light guide plate is further provided with a high-reflection layer, the high-reflection layer is arranged at a position corresponding to the position of the second pixel area of the view field of the display screen, and the high-reflection layer is used for blocking the light of the LEDs from reaching the second pixel area of the view field.

In one possible design, the display screen is a fast response liquid crystal display.

In one possible design, the display device is a virtual reality display device.

The display device has the advantages that light from the LEDs is concentrated to reach the area of the FoV effective pixels through the light guide plate and the light outlet microstructures through the display adopting the backlight module, the LED light is prevented from reaching the area of invalid pixels outside the FoV, and waste of light energy is avoided.

Drawings

FIG. 1 is a schematic diagram of an optical FoV active pixel area and an optical FoV inactive pixel area in a VR display device;

FIG. 2 is a schematic diagram comparing a hold type display with an impulse type display provided in the examples of the present application;

FIG. 3 is a schematic diagram illustrating the comparison of the smear when moving pictures are displayed by the conventional LCD and fast LCD plus backlight black insertion technology;

FIG. 4 is a schematic view of an AA area frame and a FoV frame viewed through a lens of a fast LCD according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of a non-IC-side dummy pixel region cut away according to an embodiment of the present disclosure;

FIG. 6 is a schematic diagram of a VR display device according to embodiments of the present application;

FIG. 7 is a schematic view of the VR display device of FIG. 6 with cross-hatching;

FIG. 8 is a schematic diagram of an optical path provided by an embodiment of the present application;

FIG. 9 is a schematic diagram of another VR display device provided in embodiments of the present application;

fig. 10 is a schematic view of another optical path provided in the embodiment of the present application.

Detailed Description

The embodiment of the application provides a VR display device, and the VR display device uses a fast response liquid crystal display (fast LCD) of a backlight black insertion technology, so that the problem of smear caused when a display screen displays a moving picture is reduced, and the degree of dizzy and nausea caused when a user uses the VR display device is reduced.

The display principle of the LCD is to change the transmittance of the liquid crystal layer to different gray-scale pixels by changing the driving voltage. The switching response time of the slowest order of the conventional in-plane switching (IPS) LCD can be as high as 30-40 milliseconds (msec), and the fast LCD technology can reduce the switching response time of the slowest order to 5-6 msec by reducing the cell thickness, changing the liquid crystal material, changing the design of the pixel electrode and the like, and then the hold type display is changed into the impulse type display by matching with the backlight module black insertion technology, so that the smear can be effectively reduced. As shown in FIGS. 2 and 3, FIG. 2 is a schematic diagram comparing a smear of a hold type display with an impulse type display; FIG. 3 is a schematic diagram of the comparison of the smear when moving pictures are displayed by the conventional LCD and fast LCD plus backlight black insertion technology. In fig. 2, the smear length of the black inserted type display is 4 pixels (pixels), and the smear length of the 50% black inserted type display is only 2 pixels. In fig. 2, ppf is an abbreviation of pixel per frame (pixel per frame). It is also apparent from the image display of fig. 3 that the smear of the motion of the dynamic image in the conventional LCD is more severe than the smear of the motion of the dynamic image in the fast response LCD with the backlight black-insertion technique.

The Active Area (AA) of the fast response liquid crystal display is generally square. In order to simulate human eyes, after the VR display device passes through the lens, human eyes can see an approximately circular FoV, so that pixels in the AA cannot be completely displayed in the FoV through the lens, that is, the pixels in the AA cannot be all seen in a field of view, as shown in fig. 4 and fig. 1, the pixels in the FoV can be seen by a user and are called effective pixels, and an area in the FoV is called an effective pixel area; pixels outside the FoV are not visible to the user and are called invalid pixels, and regions outside the FoV are called invalid pixel regions. This results in a waste of pixels. For the fast response liquid crystal display, the waste of the light energy of the backlight module is also caused.

In order to reduce the waste of light energy, as shown in fig. 5, compared with fig. 1 or fig. 4, the glass of the ineffective pixel region is cut off to reduce the waste of light energy caused by the ineffective pixel region. Here, the LCD is constructed by two parallel glass substrates, and transparent electric films are coated on the inner sides of the two glass substrates, and depending on the display mode, an alignment film capable of aligning liquid crystal molecules in a certain direction is formed on the surfaces of the electric films, and then liquid crystal is injected between the two glass substrates to seal them. Therefore, the glass for cutting the ineffective pixel region is the glass substrate corresponding to the ineffective pixel region, and the fast LCD shown in fig. 5 after the ineffective pixel region is cut is further obtained. As shown in fig. 5, only a part of the glass of the ineffective pixel area corresponding to the AA area is cut. The reason why the glass of the other invalid pixel region in the AA region is not cut is that the fast LCD panel is provided with a driving Integrated Circuit (IC) on the side, and the glass substrate has a circuit trace, so that the glass of the invalid pixel region on the non-IC side can be cut only. Therefore, the invalid pixel area near the IC side has the problem of light energy waste of the backlight module.

In order to further reduce the waste of light energy, the application provides a display device, including backlight unit and display screen, backlight unit includes emitting diode LED and light guide plate, is provided with the light-emitting microstructure on the light guide plate, and the position that sets up of light-emitting microstructure is corresponding with the first pixel region position of the visual field of display screen, and the first pixel region of visual field here is the effective pixel region of visual field, and LED's light passes through the first pixel region of visual field that the light-emitting microstructure reachd the display screen.

Optionally, in this embodiment of the present application, the display screen is a fast response liquid crystal display.

Optionally, in an embodiment of the present application, the display device is a virtual reality VR display device.

The following describes aspects of embodiments of the present application, taking as an example that the display device is a VR device. It should be noted that, in this embodiment, the effective pixel area of the field of view of the display screen may be referred to as the first pixel area of the field of view of the display screen; the inactive pixel area of the field of view of the display screen may be referred to as a second pixel area of the field of view of the display screen.

The VR display device provided by the embodiment of the application uses a display including a backlight module, and the display uses a fast LCD which is not self-luminous, as shown in fig. 6, and fig. 6 is a schematic cross-sectional view of fig. 7.

As shown in fig. 6, the VR display device includes a backlight module and a display screen, where the display screen is a fast LCD. Liquid crystal displays may also be referred to as liquid crystal cells. The backlight module includes a Light Emitting Diode (LED) and a light guide plate. A light-emitting microstructure is arranged on the light guide plate at a position corresponding to the effective pixel area, and the light-emitting microstructure is used for light to pass through; light generated by the LED can reach the display area of the liquid crystal box through the light guide plate and the light outlet microstructures. And the light reaches the effective pixel area of the FoV through the light-emitting microstructure in a concentrated manner, so that the light generated by the LED reaches the ineffective pixel area of the FoV through the light guide plate, and the waste of light energy is reduced. The light path diagram of the light generated by the LED reaching the effective pixel area through the light guide plate and the light-emitting microstructures is shown in fig. 8.

The light-emitting microstructures are used for destroying the total reflection of light rays in the light guide plate; when the light meets the light-emitting microstructure, the total reflection condition is destroyed, and the light leaves the light guide plate and enters the liquid crystal box.

Optionally, in this embodiment, the light-emitting microstructures near the LED are arranged at a lower density, and the light-emitting microstructures far from the LED are arranged at a higher density, so as to ensure uniform light distribution of the backlight module.

The light-emitting microstructures may be convex or concave, and their specific shape is not limited in this embodiment, but all of them can uniformly emit light. In addition, it should be noted that there are many manufacturing methods for the light-emitting microstructure, for example, the light-emitting microstructure is directly printed on the light guide plate, or the microstructure is snapped on the mold core and then is engraved on the light guide plate to form the light-emitting microstructure on the light guide plate, and the manufacturing method of the light-emitting microstructure is not limited in the embodiment of the present application.

Optionally, as shown in fig. 6, the VR display device further includes a reflective sheet and some other devices. The reflector plate is arranged on the other side of the light source for reflecting the light generated by the LED back to the light guide plate in the transmission process of the light guide plate so as to improve the use efficiency of the light.

Adopt this VR display device can be effectual, the waste of further reduction light energy. Under the same brightness setting, the power consumption of the backlight module can be reduced by about 10%, or the display brightness of the VR display device can be effectively increased by 10%.

As shown in fig. 9, embodiments of the present application further provide a VR display device, in comparison with the VR display device shown in fig. 6, in the light guide plate, a high reflection layer is added at a position corresponding to a second pixel region of a field of view of the display screen, that is, a high reflection layer is provided at a position of the light guide plate corresponding to an invalid pixel region of the field of view of the display screen. The highly reflective layer prevents light from passing through to the inactive pixel areas, further reducing the waste of light energy compared to the VR display device provided in fig. 6.

Wherein, the material of the high reflection layer can be metal. For example, metals such as aluminum and silver.

In this embodiment, the high reflection layer may be a metal sheet or a metal plating film, or may be a white metallic paint or a white reflection sheet. If a high reflection layer with higher reflectivity is needed, a plurality of high reflection layers with coating films can be arranged to enable the high reflection layer to have higher reflectivity.

Fig. 9 is a schematic diagram of a light path of light generated by an LED of the VR display device, which reaches an effective pixel area through a light guide plate and a light-emitting microstructure, as shown in fig. 10.

By adopting the VR display device provided by the embodiment of the application, the waste of the light energy of the VR display device in the AA area invalid pixel area outside the FoV is reduced. Meanwhile, the display brightness of the VR display device can be effectively increased by 10%, or the power consumption of the display backlight module can be reduced by 10% under the condition of the same brightness.

It should be noted that the technical solution of the embodiment of the present application can be applied not only to the VR field, but also to all devices or apparatuses having invalid pixel areas in the non-self-luminous display AA area.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A display device is characterized by comprising a backlight module and a display screen, wherein the display screen comprises a view field first pixel area and a view field second pixel area, the view field first pixel area and the view field second pixel area are active areas of the display screen, the backlight module comprises a Light Emitting Diode (LED) and a light guide plate, a light emitting microstructure is arranged on the light guide plate corresponding to the view field first pixel area, and light of the LED reaches the view field first pixel area through the light emitting microstructure; the light-emitting microstructures are not arranged in the light guide plate corresponding to the second pixel areas of the view fields, so that the light of the LEDs is prevented from reaching the second pixel areas of the view fields through the light guide plate;

the high-reflection layer is arranged on the light guide plate, the arrangement position of the high-reflection layer corresponds to the position of a second pixel area of a view field of the display screen, and the high-reflection layer is used for preventing the light of the LED from reaching the second pixel area of the view field;

the backlight side of the light guide plate is provided with a reflector plate for reflecting light rays back to the light guide plate;

the display screen is a fast response liquid crystal display;

the display device is a virtual reality display device.