TWI658294B - Backlight module with switchable viewing angles and related electronic device - Google Patents

Abstract

In the backlight module with switchable viewing angle, the first light guide plate is used to guide the first light provided by the first light source module to a light emitting direction, and the second light guide plate is used to guide the first light provided by the second light source module. The second light is guided to the light emitting direction. The first reflecting plate is disposed between the first light guide plate and the second light guide plate, and is configured to reflect the light leakage from the first light guide plate and introduce the light into the first light guide plate. The second reflecting plate is used to reflect the leaked light of the second light guide plate into the second light guide plate. The grating layer is disposed between the first reflective plate and the second light guide plate, and is used to reduce the light emitting angle of the second light guide plate.

Description

Backlight module with switchable viewing angle and related electronic device

The present invention provides a backlight module and related electronic devices, and more particularly, a backlight module and related electronic devices with switchable viewing angles to provide a privacy function.

With the development of science and technology, portable electronic devices, such as mobile phones, e-books or notebook computers, have become indispensable tools for people to communicate in daily life and work. Users often use portable devices in crowded public places (such as on mass transit systems) for instant messaging, browsing the web, and running social software, which greatly increases the risk of personal data leakage. At present, the viewing angle narrowing technology or anti-peeping technology used in the industry usually attaches or installs a polymer film with anti-peep function on the surface of the display device. The polymer film has the physical properties of blocking light, so that The user can see the display screen of the flat display device in a fixed field of view, but other people cannot see the display screen in areas outside the field of view. However, the disadvantage of using this polymer film is that a film with a certain thickness must be additionally attached to the display device, which will increase the cost and thickness of the flat display device. In addition, the plug-in anti-peeper also requires the user to manually switch the anti-peeper or not, which causes inconvenience in use.

The present invention provides a backlight module, which includes a first light source module for providing a first light; a second light source module for providing a second light; a first light guide plate for The first light is guided to a light emitting direction; a second light guide plate is used to guide the second light to the light emitting direction; a first reflecting plate is disposed between the first light guide plate and the second light guide plate For reflecting the light leakage of the first light guide plate into the first light guide plate; a second reflection plate for reflecting the light leakage of the second light guide plate into the second light guide plate; and a grating layer Is disposed between the first reflective plate and the second light guide plate, and is used to reduce the light-emitting angle of the second light guide plate.

The invention further provides an electronic device, which includes a display screen, a backlight module, and a controller. The backlight module includes a first light source module for providing a first light, a second light source module for providing a second light, and a first light guide plate for guiding the first light. To the display screen; a second light guide plate for guiding the second light to the display screen; a first reflective plate disposed between the first light guide plate and the second light guide plate for Light leakage reflection of the first light guide plate is introduced into the first light guide plate; a second reflection plate is used to reflect the light leakage of the second light guide plate into the second light guide plate; and a grating layer is disposed on the first light guide plate. A reflecting plate and the second light guide plate are used to reduce a light emitting angle of the second light guide plate. The controller is used to determine a display mode selected by the electronic device; when it is determined that the electronic device selects a sharing mode, the first light source module is turned on to provide the first light with a first light angle to the display screen And when it is judged that the electronic device selects a privacy mode, turning on the second light source module to provide the second light with a second light angle to the display screen, wherein the second light angle is smaller than the first light angle .

10‧‧‧Reflective Brightening Film

20‧‧‧ cymbals

30‧‧‧ diffuser

40‧‧‧ grating layer

42‧‧‧light blocking area

44‧‧‧light-emitting area

50‧‧‧ Hole

52‧‧‧display

54‧‧‧Gate driving circuit

56‧‧‧Source driving circuit

58‧‧‧controller

61‧‧‧First Zone

62‧‧‧Second Zone

100, 200‧‧‧ backlight module

500‧‧‧ electronic device

610 ~ 650‧‧‧step

S1, S2 ‧‧‧ user's sight

M1, M2‧‧‧ screen

LPG1, LPG2‧‧‧light guide plate

RF1, RF2‧‧‧ reflector

LED1, LED2‧‧‧light source module

FIG. 1 is a schematic diagram of a backlight module with a switchable viewing angle according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a backlight module with a switchable viewing angle according to another embodiment of the present invention.

Figure 3 shows a top view of a grating layer in an embodiment of the invention.

FIG. 4 shows a top view of the light guide plate in the embodiment of the present invention.

FIG. 5 shows a functional block diagram of an electronic device to which the backlight module can be applied in the embodiment of the present invention.

FIG. 6 shows a flowchart of the operation of the electronic device in the embodiment of the present invention.

FIG. 7 and FIG. 8 show schematic diagrams of the backlight module when the backlight module operates in a sharing mode according to an embodiment of the present invention. FIG. 9 and FIG. 10 show schematic diagrams of the backlight module when the backlight module is operated in a privacy mode according to an embodiment of the present invention.

FIG. 11 shows a schematic diagram of an electronic device operating in a sharing mode according to an embodiment of the present invention.

FIG. 12 shows a schematic diagram of an electronic device operating in a privacy mode according to an embodiment of the present invention.

FIG. 1 is a schematic diagram of a backlight module 100 with a switchable viewing angle according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a backlight module 200 with a switchable viewing angle according to another embodiment of the present invention. The backlight module 100 and the backlight module 200 each include a dual brightness enhancement film (DBEF) 10, a prism film 20, a diffuser film 30, a grating layer 40, two Light guide plate LPG1 And LPG2, two reflection plates RF1 and RF2, and two light source modules LED1 and LED2.

In the present invention, the reflection plate RF1 is provided between the lower side of the light guide plate LPG1 and the upper side of the light guide plate LPG2, and the reflection plate RF2 is provided under the light guide plate LPG2. The light guide plates LPG1 and LPG2 can respectively guide the point light sources provided by the light source modules LED1 and LED2 into a planar light source to the diffusion film 30. In the backlight module 100 shown in FIG. 1, the light source modules LED1 and LED2 are respectively disposed on the same side of the light guide plates LPG1 and LPG2. In the backlight module 100 shown in FIG. 2, the light source modules LED1 and LED2 are disposed on opposite sides of the light guide plates LPG1 and LPG2, respectively. However, the positions of the light source modules LED1 and LED2 do not limit the scope of the present invention.

The bottom surfaces of the light guide plates LPG1 and LPG2 contain printed pattern diffusion points. When the light sources provided by the light source modules LED1 and LED2 reach the bottom surfaces of the light guide plates LPG1 and LPG2, the use of dense and different diffusion point pattern designs can destroy the entire light Reflect, and then diffuse the reflected light to various angles to form a planar light source, and guide the light to the upper surfaces of the light guide plates LPG1 and LPG2. On the other hand, the reflective plates RF1 and RF2 can reflect the light leakage from the bottom surfaces of the light guide plates LPG1 and LPG2 to the light guide plates LPG1 and LPG2 respectively, thereby improving the optical use efficiency.

FIG. 3 shows a top view of the grating layer 40 in the embodiment of the present invention. The grating layer 40 includes a light-blocking region 42 (black-coated portion) and a light-emitting region 44. The light-blocking region 42 can be formed by printing an opaque material on the light-emitting side (upper surface) of the light guide plate LPG2 or under the reflection plate RF1. Therefore, the light emitting angle of the light guide plate LPG2 can be reduced. In the embodiment shown in FIG. 3, the grating layer 40 is designed with a stripe pattern. In other embodiments, the light blocking region of the grating layer 40 The domain 42 and the light-exiting region 44 can also be designed with other patterns. The pattern of the grating layer 40 does not limit the scope of the present invention.

FIG. 4 shows a top view of the light guide plate LPG1 in the embodiment of the present invention. The light guide plate LPG1 includes a first area 61 corresponding to the light-exiting area 44 and a second area 62 corresponding to the light-blocking area 42. The light guide plate LPG1 includes a plurality of light-transmissive holes 50 at least in the first area 61. The emitted light passed. It should be noted that the shape and number of the holes 50 do not limit the scope of the present invention.

In the backlight module 100 shown in FIG. 1 and the backlight module 200 shown in FIG. 2, the diffusion film 30 is disposed above the light guide plate LPG1, and its function is to make the emitted light more uniform. A cymbal 20 having a light-concentrating effect may be disposed above the diffusion film 30, thereby increasing the directivity of the emitted light to improve frontal brightness. A reflective brightness-enhancing film 10 including a ytterbium structure can be disposed above the cymbal 20, which can concentrate the scattered light to the on-axis to further increase the brightness. However, the arrangement of the optical elements such as the reflective brightness enhancement film 10, the louver 20, and the diffusion film 30 does not limit the scope of the present invention.

FIG. 5 shows a functional block diagram of an electronic device 500 to which the backlight modules 100 and 200 can be applied according to an embodiment of the present invention. The electronic device 500 includes a display screen 52, a gate driving circuit 54, a source driving circuit 56, a controller 58, and a backlight module 100 or 200. The backlight modules 100 and 200 of the present invention can be applied to any electronic device 500 including a display screen, such as a notebook computer, a tablet computer, a mobile phone, or a television. However, the type of the electronic device 500 does not limit the scope of the present invention.

The electronic device 500 can operate in a sharing mode or a privacy mode. FIG. 6 shows a flowchart of the operation of the electronic device 500 in the embodiment of the present invention, which includes the following steps:

Step 610: Start.

Step 620: The controller 58 determines the display mode selected by the electronic device 500; when the sharing mode is selected, step 630 is performed; when the privacy mode is selected, step 640 is performed.

Step 630: The controller 58 turns on the light source module LED1; step 650 is performed.

Step 640: The controller 58 turns on the light source module LED2; step 650 is performed.

Step 650: The controller 58 controls the gate driving circuit 54 and the source driving circuit 56 to drive the display screen 52. Step 620 is performed.

In step 620, the user may use a keyboard or software to set a display mode of the electronic device 500. When the sharing mode is selected, the controller 58 of the electronic device 500 turns on the light source module LED1 in step 630; when the privacy mode is selected, the controller 58 of the electronic device 500 turns on the light source module LED2 in step 640. In one embodiment, the present invention may use the AUX channel of the embedded display port (eDP) or the general-purpose input / output (GPIO) of the controller 58 to set the display mode of the electronic device 500. . However, the setting mode of the display mode does not limit the scope of the present invention.

FIG. 7 is a schematic diagram of the backlight module 100 in the sharing mode according to an embodiment of the present invention. FIG. 8 shows a schematic diagram of the backlight module 200 in the shared mode according to an embodiment of the present invention. In the sharing mode, the light source module LED1 is on and the light source module LED2 is off. At this time, the light guide plate LPG1 and the reflection plate RF1 can reflect the light emitted by the light source module LED1 into the diffusion film 30 and pass through the cymbals 20 in sequence And reflective brightening film 10, The backlight modules 100 and 200 of the present invention can provide a light source with a light output angle of θ 1 to the display screen 52 in a sharing mode.

FIG. 9 shows a schematic diagram of the backlight module 100 in a privacy mode according to an embodiment of the present invention. FIG. 10 shows a schematic diagram of the backlight module 200 in a privacy mode according to an embodiment of the present invention. In the privacy mode, the light source module LED1 is turned off and the light source module LED2 is turned on. At this time, the light guide plate LPG2 and the reflection plate RF2 can reflect the light emitted by the light source module LED2 into the grating layer 40 to reduce the light angle of view, and then guide the light through The hole 50 of the light plate LPG1 reaches the diffusion film 30. After passing through the cymbal 20 and the reflective brightness enhancement film 10 in sequence, the backlight modules 100 and 200 of the present invention can provide a light source with a light viewing angle of θ 2 to the display screen 52 in a privacy mode, where θ 2 <θ 1.

FIG. 11 shows a schematic diagram of the electronic device 500 operating in a sharing mode according to an embodiment of the present invention. FIG. 12 shows a schematic diagram of the electronic device 500 operating in a privacy mode according to an embodiment of the present invention. In FIG. 11 and FIG. 12, the user A and the user B are both located in the display range of the electronic device 500, where the user A is an operator of the electronic device 500, the arrow S1 represents the line of sight of the user A, and the arrow S2 represents use In the sight of the user B, the picture M1 is an image seen by the user A, and the picture M2 is an image seen by the user B. In the sharing mode, the backlight module 100 or 200 of the present invention in the electronic device 500 can provide a larger light angle θ 1, so that both the user A and the user B can see the image on the display screen 52. In the privacy mode, the backlight module 100 or 200 of the present invention in the electronic device 500 can provide a smaller light angle of view θ 2. At this time, only the user A can see the image on the display screen 52, and the user B can only see Go to black screen to provide anti-peep function.

In summary, the present invention provides a backlight module with switchable viewing angles. When applied to an electronic device, it can provide light with a first light angle to the display screen in the sharing mode, and provide a backlight module in the privacy mode. The light from the second light angle reaches the display screen, wherein the second light angle is smaller than the first light angle.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the scope of patent application of the present invention shall fall within the scope of the present invention.

Claims (7)

A backlight module includes a first light source module for providing a first light, a second light source module for providing a second light, and a first light guide plate. Containing a plurality of transparent holes for guiding the first light to a light emitting direction; a second light guide plate for guiding the second light to the light emitting direction; a first reflecting plate for setting Between the first light guide plate and the second light guide plate, the light leakage of the first light guide plate is reflected and introduced into the first light guide plate; a second reflection plate is disposed on the second light guide plate and faces away from the second light guide plate. One side of the first reflection plate is used to reflect the leaked light of the second light guide plate and be introduced into the second light guide plate; and a grating layer is disposed between the first reflection plate and the second light guide plate for The light emitting angle of the second light guide plate is narrowed, and the grating layer includes: a light emitting area corresponding to the plurality of holes for allowing the second light guided by the second light guide plate to pass through; and a block A light region containing an opaque material to block the light guided by the second light guide plate To attract the second light, the opaque material is formed on one side of the second light guide plate facing the first reflective plate, or formed on one side of the first light guide plate facing the second light guide plate. The backlight module according to claim 1, further comprising: a diffuser film for guiding the first light guided by the first light guide plate or the second light guide plate. Second light is scattered to increase the uniformity of the first light or the second light; a prism film is used to increase the directivity of the first light or the second light; and a reflective brightness enhancement film (dual brightness enhancement film, DBEF), which is used to focus the first light or the second light to an on-axis to increase the brightness. An electronic device includes: a display screen; a backlight module including: a first light source module for providing a first light; a second light source module for providing a second light; A first light guide plate including a plurality of light-transmissive holes for guiding the first light to the display screen; a second light guide plate for guiding the second light to the display screen; a A first reflecting plate is disposed between the first light guiding plate and the second light guiding plate, and is configured to reflect the leaked light of the first light guiding plate into the first light guiding plate; a second reflecting plate is provided on the first light guiding plate; The two light guide plates face away from one side of the first reflection plate, and are used to reflect the light leakage from the second light guide plate and be introduced into the second light guide plate; and a grating layer is disposed on the first reflection plate and the second light guide plate. Between the light plates, used to reduce the light output angle of the second light guide plate, the grating layer includes: a light output area, which is located corresponding to the plurality of holes, and is used for the second light guide plate guided by the second light guide plate Light passes; and a light-blocking area, which contains opaque material to Blocking the second light guided by the second light guide plate, the opaque material is formed on one side of the second light guide plate facing the first reflecting plate, or is formed on the first reflecting plate facing the second One side of the light guide plate; and a controller for: determining a display mode selected by the electronic device; when determining that the electronic device selects a sharing mode, turning on the first light source module to provide a first light The first light from the viewing angle reaches the display screen; and when it is determined that the electronic device selects a privacy mode, the second light source module is turned on to provide the second light with a second light viewing angle to the display screen, wherein the The second light angle of view is smaller than the first light angle of view. The electronic device according to claim 3, wherein the backlight module further comprises: a diffusion film for guiding the first light guided by the first light guide plate or the first light guided by the second light guide plate. Two light scatters to increase the uniformity of the first light or the second light; a diaphragm to increase the directivity of the first light or the second light; and a reflective brightness enhancement film to apply the light The first light or the second light is focused to a positive viewing angle to increase the brightness. The electronic device according to claim 3, wherein: in the sharing mode, the first light provided by the first light source module is guided by the first light guide plate to the display screen; and in the privacy mode At this time, the second light provided by the second light source module is sequentially guided to the display screen by the second light guide plate and the first light guide plate. The electronic device according to claim 3, further comprising an embedded display port (eDP). The embedded display port includes an AUX channel for selecting the display mode. The electronic device according to claim 3, wherein the controller includes a general-purpose input / output (GPIO) for selecting the display mode.