CN108957816A - Display component, display device and driving method thereof - Google Patents

Abstract

The application provides a display screen assembly, a display device and a driving method thereof. The display screen assembly comprises a display screen, a light sensing element and a light sensing driving assembly; the display screen comprises a first substrate, a second substrate and a liquid crystal layer, wherein: the liquid crystal display panel comprises a first substrate, a second substrate, a liquid crystal layer and a liquid crystal layer, wherein the first substrate and the second substrate are oppositely arranged, the liquid crystal layer is arranged between the first substrate and the second substrate, and the liquid crystal layer comprises a plurality of liquid crystal molecules; the display screen provides a display picture for a user at one side of the first substrate far away from the second substrate, and the light sensing element is arranged at one side of the liquid crystal layer far away from the first substrate; the light sensation driving component is arranged on the first substrate and/or the second substrate and drives the liquid crystal molecules to rotate when the display screen is in a screen resting state, so that light of the light sensation element can be transmitted in the liquid crystal layer. This makes it possible to dispose the light-sensing element under the screen in the liquid crystal display device.

Description

Display component, display device and driving method thereof

technical field

The present application relates to the field of display technology, in particular to a display screen component, a display device and a driving method thereof.

Background technique

The existing photosensitive element has been transferred to the bottom of the screen on OLED (Organic Light-Emitting Diode, Organic Light-Emitting Diode) products.

As for liquid crystal display devices, LTPS (Low Temperature Poly-silicon, low-temperature polysilicon technology) is widely used because of its ultra-thin, light weight, low power consumption, and can provide brighter colors and clearer images. However, LTPS usually adopts the FFS driving principle, that is, when the display screen is off, the liquid crystal light valve is in a constant dark mode, so that the light of the light sensing element cannot be transmitted in the display screen, thus limiting the use of the light sensing element in the liquid crystal display device. off-screen applications.

Contents of the invention

The application provides a display screen assembly, which includes a display screen, a photosensitive element, and a photosensitive drive assembly;

The display screen includes a first substrate, a second substrate and a liquid crystal layer, wherein:

The first substrate and the second substrate are arranged oppositely, the liquid crystal layer is arranged between the first substrate and the second substrate, and the liquid crystal layer includes a plurality of liquid crystal molecules;

The display screen provides a display screen to the user on a side of the first substrate away from the second substrate, and the photosensitive element is arranged on a side of the liquid crystal layer away from the first substrate;

The photosensitive driving component is arranged on the first substrate and/or the second substrate, and drives the liquid crystal molecules to rotate when the display screen is off, so that the light of the photosensitive element can be transport in the liquid crystal layer.

The present application also provides a display device, which includes a display screen assembly and a backlight module, the display screen assembly includes the above-mentioned display screen assembly, and the backlight module provides backlight for the display screen of the display screen assembly .

The present application also provides a method for driving a display device, the display device includes a display screen assembly and a backlight module, the display screen assembly includes a display screen, a photosensitive element, and a photosensitive driving assembly, and the display screen includes a first substrate , a second substrate and a liquid crystal layer, wherein the first substrate and the second substrate are oppositely disposed, the liquid crystal layer is disposed between the first substrate and the second substrate, and the liquid crystal layer includes a plurality of liquid crystals molecular;

The display screen provides a display screen to the user on a side of the first substrate away from the second substrate, and the photosensitive element is arranged on a side of the liquid crystal layer away from the first substrate;

The driving method includes:

The backlight module stops providing backlight to the display screen, and the first substrate and the second substrate stop driving the liquid crystal molecules in the liquid crystal layer to rotate, and the display screen is in a screen off state; the light The sensing driving component drives the liquid crystal molecules in the liquid crystal layer to rotate, so that the light of the photosensitive element can be transmitted in the liquid crystal layer.

In the present application, by arranging a photosensitive driving component on the first substrate and/or the second substrate, the liquid crystal molecules are driven to rotate when the display screen is off, so that the light of the photosensitive element can be transmitted in the liquid crystal layer, thereby achieving light The sensing element is arranged under the screen in the liquid crystal display device.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

FIG. 1 is a schematic diagram of the overall structure of a display screen assembly provided by an embodiment of the present application;

FIG. 2 is a schematic diagram of a disassembled structure of the display screen assembly shown in FIG. 1;

Fig. 3 is a schematic cross-sectional structure diagram of A1A2 dotted line shown in Fig. 2;

Fig. 4 is a schematic cross-sectional structure diagram of the dotted line B1B2 shown in Fig. 2;

FIG. 5 is a schematic top view of a TFT substrate provided in an embodiment of the present application;

FIG. 6 is a schematic structural view of the photosensitive driving component of the present application disposed on a TFT substrate;

FIG. 7 is a schematic structural diagram of a display device 700 provided in an embodiment of the present application;

FIG. 8 is a schematic flowchart of a method for driving a display device provided in an embodiment of the present application;

FIG. 9 is a waveform diagram of a driving signal of the driving method shown in FIG. 8 .

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific embodiments described here are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only some structures related to the present application are shown in the drawings but not all structures. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

Please refer to FIG. 1 and FIG. 2 . FIG. 1 is a schematic diagram of an overall structure of a display screen assembly provided by an embodiment of the present application, and FIG. 2 is a schematic diagram of a disassembled structure of the screen assembly shown in FIG. 1 . As shown in FIG. 1 , the display screen assembly 10 includes a display screen 100 , a photosensitive element 200 and a photosensitive driving assembly 300 .

The display screen 100 includes a display area A11 and a non-display area A12.

In other embodiments, the display screen 100 may only include the display area A11, that is, a full screen.

The display screen 100 includes a first substrate 103 , a second substrate 104 and a liquid crystal layer 105 .

The first substrate 103 and the second substrate 104 are disposed opposite to each other. The liquid crystal layer 105 is disposed between the first substrate 103 and the second substrate 104 . The liquid crystal layer 105 includes a plurality of liquid crystal molecules 1051 . The liquid crystal layer 105 is disposed corresponding to the display area A11 of the display screen 100 . The liquid crystal molecules 1051 have anisotropy and can rotate in the electric field formed by the first substrate 103 and the second substrate 104, so that the incident light passes through and displays a display image to the user. As shown in FIG. 1 , the light is incident from the second substrate 104 , passes through the liquid crystal layer 105 , and exits on the side of the first substrate 103 away from the second substrate 104 , so as to provide a display image to the user.

The first substrate 103 can be a CF substrate. Please refer to FIGS. 2-4 . FIG. 2 is a schematic top view of the CF substrate. The CF substrate 103 includes a CF substrate 1011 , a filter layer 1012 and a black matrix layer 1013 .

Wherein, the CF substrate 1011 can be made of glass, plastic and other materials.

The filter layer 1012 and the black matrix layer 1013 are disposed on the base 1011 .

The filter layer 1012 includes a first filter unit 1014 for filtering blue light and green light, a second filter unit 1015 for filtering blue light and red light, and a third filter unit 1016 for filtering green light and red light . That is to say, the first filter unit 1014 emits red light, the second filter unit 1015 emits green light, and the third filter unit 1016 emits blue light. The first filter unit 1014 , the second filter unit 1015 and the third filter unit 1016 are arranged sequentially.

The black matrix layer 1013 is disposed between two adjacent filter layers 1012 .

Further, the CF basically includes an insulating layer 1017 disposed on a side of the filter layer 1012 and the black matrix layer 1013 away from the CF substrate 1011 .

The second substrate 104 can be a TFT substrate. Please refer to FIG. 5 . FIG. 5 is a schematic top view of a TFT substrate. The TFT substrate 104 may include a TFT substrate 1020 , a plurality of scan lines S, data lines D, switch transistors 1021 and pixel electrodes 1022 disposed on the TFT substrate 1020 .

The scan lines S and the data lines D surround a plurality of pixel units 1023 . The switch tube 1021 and the pixel electrode 1022 are arranged in the pixel unit 1023 . The control end of the switch tube 1021 is electrically connected to the scan line S, the input end is electrically connected to the data line D, and the output end is electrically connected to the pixel electrode 1022 .

When the scan line S provides a turn-on scan line signal to the control terminal of the switch transistor 1021 , the switch transistor 1021 is turned on, and the data line D provides a data signal to the input terminal of the switch transistor 1021 to output to the pixel electrode 1022 . After receiving the data signal, the pixel electrode 1022 cooperates with the common electrode on the CF substrate 103 to form an electric field that can rotate the liquid crystal molecules 1051 of the liquid crystal layer 105 . Thus, light incident on the side of the TFT substrate 104 can pass through the liquid crystal layer 105 and exit from the side of the CF substrate 103 for display. This state may be a bright screen state of the display screen 100 , that is, a display state.

When the scan line S provides a turn-off scan line signal to the control terminal of the switch tube 1021 , the switch tube 1021 is turned off, the data line D stops providing data signals to the input terminal of the switch tube 1021 , and the pixel electrode 1022 does not receive the data signal. Therefore, there is no electric field between the CF substrate 103 and the TFT substrate 104 that can rotate the liquid crystal molecules 1051 of the liquid crystal layer 105 . The liquid crystal molecules 1051 are in the original state, that is, in the off state, which blocks the transmission of light, and realizes that the display screen 100 is turned off. This state may be an off-screen state of the display screen 100 , that is, a non-display state.

The photosensitive element 200 may include an infrared light sensor, an ambient light sensor, and the like. Among them, the infrared light sensor can achieve the purpose of sensing by emitting and receiving infrared light, for example, the infrared light distance sensor can achieve the purpose of sensing distance by emitting and receiving infrared light. The ambient light sensor can sense the intensity of the ambient light by receiving the ambient light.

The photosensitive element 200 is arranged on the side of the liquid crystal layer 105 away from the first substrate 103, as shown in FIG. The photosensitive element 200 is blocked and hidden by the display screen 100 . Thus, the setting position on the non-display area A12 of the display screen 100 can be saved, so as to achieve the effect of a narrow frame or a full screen.

In other embodiments, the photosensitive element 200 can also be disposed between the second substrate 104 and the liquid crystal layer 105 . The photosensitive element 200 can also be partially disposed in the display area A11.

Since the photosensitive element 200 is disposed on the side of the liquid crystal layer 105 away from the first substrate 103 , the light from the photosensitive element 200 needs to pass through the liquid crystal layer 105 . It is affected by the rotation state of the liquid crystal molecules 1051 in the liquid crystal layer 105 . Wherein, the light of the photosensitive element 200 includes the light emitted by the photosensitive element 200 and the light received by the photosensitive element 200 or only includes the light received by the photosensitive element 200 . It is specifically related to the type of the photosensitive element 200 .

According to the foregoing, when the display screen 100 is an off screen, the liquid crystal molecules 1051 are not rotated and are in the original state, which will block the transmission of light at this time, which will have a great impact on the application of the photosensitive element 200. Impact. Based on this, the present application provides a photosensitive driving component 300 for driving the liquid crystal molecules 1051 to rotate when the display screen 100 is off, so that the light of the photosensitive element 200 can be transmitted in the liquid crystal layer 105 .

Specifically, see Figures 2 and 4 again. The photosensitive driving assembly 300 is disposed on the CF substrate. And it is located in the display area corresponding to the photosensitive area 1018 of the photosensitive element 200 .

The photosensitive driving assembly 300 includes a plurality of driving electrodes 301 arranged at intervals and a plurality of driving signal lines 302 arranged at intervals. The number of the driving electrodes 301 and the driving signal lines 302 are the same and corresponding to each other, and the driving signal lines 302 provide driving signals to the driving electrodes 301 when the display screen 100 is off.

Wherein, the potentials of the driving signals received by the two adjacent driving electrodes 301 are opposite, so that the polarities of the two adjacent driving electrodes 301 are opposite. Thus, an electric field is formed between two adjacent driving electrodes 301 to drive the liquid crystal molecules 1051 in the liquid crystal layer 105 to rotate. The direction of the electric field formed between two adjacent driving electrodes 301 is perpendicular to the direction of the electric field formed between the first substrate 103 and the second substrate 104 described above.

The potentials of the driving signals at two adjacent transmission moments are opposite, so that the polarities of the driving electrodes 301 at two adjacent transmission moments are opposite. Specifically, the driving signal in the form of alternating current can be transmitted, and the potential of the driving signal can be changed. Thus, the liquid crystal molecules 1051 in the liquid crystal layer 105 can be prevented from being polarized.

As shown in FIG. 4 , on the CF substrate, the driving electrodes 301 are disposed on the black matrix layer 1013 . The driving signal line 302 is arranged on the driving electrode 301, more specifically, the driving electrode 301 is arranged between the black matrix layer 1013 and the insulating layer 1017, the driving signal line 302 is arranged on the insulating layer 1017, and is connected through the insulating layer 1017 The holes 1019 are electrically connected to the driving electrodes 301 .

The material of the driving signal line 302 can be the same as that of the scan line S and the data line D. Referring to FIG. Similarly, the driving electrode 301 may be made of the same material as the pixel electrode, and may be an ITO (Indium Tin Oxide, tin-doped indium oxide) film.

Therefore, in this embodiment, the liquid crystal molecules 1051 can be driven to rotate through the photosensitive driving component 300 when the display screen 200 is off, so that the light of the photosensitive element 200 can be transmitted in the liquid crystal layer 105, thereby realizing the realization of the photosensitive element 200 in the liquid crystal. Displays the off-screen settings in the device.

For example, if the photosensitive element 200 is an infrared light distance sensor, when the display screen 200 is off, the driving signal line 301 of the photosensitive driving component 300 provides a driving signal to the driving electrode 301, so that two adjacent driving electrodes 301 form a The electric field drives the liquid crystal molecules 1051 of the liquid crystal layer 105 to rotate. The light emitted by the infrared distance sensor can be transmitted to the outside of the display screen 100 after being transmitted by the liquid crystal layer 105, and the light reflected from the outside of the display screen 100 can be received by the infrared distance sensor after being transmitted by the liquid crystal layer 105, so that it can pass through the light. Transmit and receive times to calculate external things, such as the distance between the user and the display.

Similarly, if the photosensitive element 200 is an ambient light sensor, when the display screen 200 is off, the driving signal line 301 of the photosensitive driving component 300 provides a driving signal to the driving electrodes 301, so that two adjacent driving electrodes 301 An electric field is formed to drive the liquid crystal molecules 1051 of the liquid crystal layer 105 to rotate. The light outside the display screen 100 can be received by the ambient light sensor after being transmitted by the liquid crystal layer 105 .

Please refer to FIG. 6 . FIG. 6 is a schematic structural view of the photosensitive driving component of the present application disposed on the TFT substrate. As shown in FIG. 6 , the TFT substrate includes a substrate 1020 , a switch transistor 1021 and a pixel electrode 1022 . The switch tube 1021 and the pixel electrode 1022 are disposed on the substrate 1011 , the control terminal 1024 of the switch tube 1021 is electrically connected to the scan line, the input terminal 1025 is electrically connected to the data line, and the output terminal 1026 is electrically connected to the pixel electrode 1022 . The switching tube 1021 can be a MOS switching tube, the control terminal 1024 can be the base of the MOS switching tube, the input terminal 1025 can be the collector of the MOS switching tube, and the output terminal 1026 can be the emitter of the MOS switching tube.

The difference from the previous embodiments is that the photosensitive driving component 300 is disposed on the side of the TFT substrate 1020 away from the switch transistor 1021 and the pixel electrode 1022 . The driving electrodes 301 are disposed on the TFT substrate 1020 , and the driving signal lines 302 are disposed on the driving electrodes 301 and electrically connected to the driving electrodes 301 . As shown in FIG. 6 , the driving signal line 302 and the driving electrode 301 are in direct contact with each other. In other embodiments, the driving electrodes 301 and the driving signal lines 302 may also have the structure described above, that is, an insulating layer is disposed between them and electrically connected through via holes on the insulating layer.

In order to prevent the photosensitive driving component 300 from blocking the transmission of light, in this embodiment, the projection of the driving electrode 301 of the photosensitive driving component 300 on the TFT substrate 1020 overlaps with the position of the switch tube 1021 . The projection of the driving signal line 302 on the TFT substrate 1020 may overlap with the position of the data line or the scan line.

The photosensitive driving component 300 described in the above embodiments is arranged on a CF substrate or a TFT substrate. It should be understood that in other embodiments, the photosensitive driving component 300 can also be arranged on a CF substrate and a TFT substrate, and its structure can be similar to the above, I won't repeat them here.

Please refer to FIG. 7 . FIG. 7 is a schematic structural diagram of a display device 700 provided in an embodiment of the present application. The display device 700 includes a display screen assembly 701 and a backlight module 702. The backlight module 702 provides backlight for the display screen of the display screen assembly 701. The display screen assembly 701 includes the above-mentioned display screen assembly.

The present application also provides a driving method of a display device. The display device is the display device 700 mentioned above. Please refer to FIGS. 8-9 for specific driving methods. FIG. 8 is a schematic flowchart of a driving method of a display device, and FIG. 9 corresponds to a waveform diagram of a driving signal of the driving method shown in FIG. 8 .

As shown in Figure 8, the driving method of this embodiment includes the following steps:

Step 801: the backlight module stops providing backlight to the display screen, and the first substrate and the second substrate stop driving the liquid crystal molecules in the liquid crystal layer to rotate, and the display screen is in an off-screen state.

Before step 801, the backlight module can also provide backlight for the display screen, and the first substrate 103 and the second substrate 104 drive the liquid crystal molecules 1051 in the liquid crystal layer 105 to rotate, and the display screen 100 is in a bright state.

Specifically, the scan line S provides a turn-on scan line signal to the control terminal of the switch transistor 1021 , the switch transistor 1021 is turned on, and the data line D provides a data signal to the input terminal of the switch transistor 1021 to be output to the pixel electrode 1022 . After receiving the data signal, the pixel electrode 1022 cooperates with the common electrode on the CF substrate to form an electric field that can rotate the liquid crystal molecules 1051 of the liquid crystal layer 105 . In this way, the backlight provided by the backlight module can pass through the liquid crystal layer 105 and then exit to display. This state may be a bright screen state of the display screen 100 , that is, a display state.

In step 801, the scan line S provides a turn-off scan line signal to the control terminal of the switch tube 1021, the switch tube 1021 is turned off, the data line D stops providing data signals to the input terminal of the switch tube 1021, and the pixel electrode 1022 does not receive the data signal. Therefore, there is no electric field that can rotate the liquid crystal molecules 1051 of the liquid crystal layer 105 between the CF substrate and the TFT substrate. The liquid crystal molecules 1051 are in the original state, that is, in the off state, which blocks the transmission of light, and realizes that the display screen 100 is turned off. This state can be a non-display state of the display screen 100 .

Step 802: The photosensitive driving component drives the liquid crystal molecules in the liquid crystal layer to rotate, so that the light of the photosensitive element can be transmitted in the liquid crystal layer.

In step 802 , the driving signal line 302 in the photosensitive driving component 300 provides a driving signal to the driving electrode 301 to drive the liquid crystal molecules 1051 in the liquid crystal layer 105 to rotate. As shown in FIG. 9 , the potentials of the driving signals received by two adjacent driving electrodes 301 are opposite, so that the polarities of the two adjacent driving electrodes 301 are opposite. Thus, an electric field is formed between two adjacent driving electrodes 301 to drive the liquid crystal molecules 1051 in the liquid crystal layer 105 to rotate. The direction of the electric field formed between two adjacent driving electrodes 301 is perpendicular to the direction of the electric field formed between the first substrate 103 and the second substrate 104 described above.

The potentials of the driving signals at two adjacent transmission moments are opposite, so that the polarities of the driving electrodes 301 at two adjacent transmission moments are opposite. Specifically, the driving signal in the form of alternating current can be transmitted, and the potential of the driving signal can be changed. Thus, the liquid crystal molecules 1051 in the liquid crystal layer 105 can be prevented from being polarized.

The principle of the light transmission of the photosensitive element in the liquid crystal layer is as described above, and will not be repeated here.

Therefore, the present application drives the liquid crystal molecules to rotate when the display screen is off, so that the light of the photosensitive element can be transmitted in the liquid crystal layer, thereby realizing the under-screen arrangement of the photosensitive element in the liquid crystal display device.

The above is only the implementation of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process conversion made by using the specification and drawings of the application, or directly or indirectly used in other related technologies fields, are all included in the scope of patent protection of this application in the same way.

Claims (12)

1. a kind of display screen component, which is characterized in that the display screen component includes display screen, light sensitive component and light sensation driving group Part；

The display screen includes first substrate, the second substrate and liquid crystal layer, in which:

The first substrate and the second substrate are oppositely arranged, and the liquid crystal layer is arranged in the first substrate and the second substrate Between, the liquid crystal layer includes multiple liquid crystal molecules；

The display screen provides a user display picture, the light sensation far from the side of the second substrate in the first substrate Side of the liquid crystal layer far from the first substrate is arranged in element；

The light sensation driving assembly is arranged on the first substrate and/or the second substrate, is in the display screen The liquid crystal molecule is driven to rotate when ceasing screen state, so that the light of the light sensitive component can transmit in the liquid crystal layer.

2. display screen component according to claim 1, which is characterized in that the light sensation driving assembly includes that multiple intervals are set The driving electrodes set and a plurality of spaced drive signal line, the driving electrodes are identical with the quantity of the drive signal line And correspond, the drive signal line provides driving signal when the display screen is in breath screen state to the driving electricity Pole.

3. display screen component according to claim 2, which is characterized in that the letter of driving received by adjacent driving electrodes Number current potential on the contrary, making the polarity of the adjacent driving electrodes opposite.

4. display screen component according to claim 2 or 3, which is characterized in that the driving of two adjacent transmission times is believed Number current potential on the contrary, making the polarity of the driving electrodes of two adjacent transmission times opposite.

5. display screen component according to claim 2, which is characterized in that the first substrate be CF substrate, described second Substrate is TFT substrate.

6. display screen component according to claim 5, which is characterized in that the display screen includes viewing area or described aobvious Display screen includes viewing area and non-display area, and the liquid crystal layer corresponds to the viewing area setting, and the light sensitive component is at least partly right Answer the viewing area.

7. display screen component according to claim 6, which is characterized in that the CF substrate includes:

CF substrate；

Filter layer and black-matrix layer are arranged in the CF substrate；

The driving electrodes of the light sensation driving assembly are arranged in the black-matrix layer and the corresponding light sensitive component, institute Drive signal line is stated to be arranged in the driving electrodes and be electrically connected with the driving electrodes.

8. display screen component according to claim 6, which is characterized in that the TFT substrate includes:

TFT substrate；

The switching tube and pixel electrode of electrical connection are arranged in the TFT substrate；

Side of the TFT substrate far from the switching tube and pixel electrode, the light is arranged in the light sensation driving assembly The driving electrodes of sense driving assembly correspond to the light sensitive component.

9. display screen component according to claim 8, which is characterized in that the driving electrodes are in the TFT substrate It projects Chong Die with the position of switching tube.

10. a kind of display device, which is characterized in that the display device includes display screen component and backlight module, the display Screen assembly includes the described in any item display screen components of claim 1-9, and the backlight module is shown to the display screen component Display screen provides backlight.

11. a kind of driving method of display device, which is characterized in that the display device includes display screen component and backlight mould Group, the display screen component include display screen, light sensitive component and light sensation driving assembly, and the display screen includes first substrate, Two substrates and liquid crystal layer, wherein the first substrate and the second substrate are oppositely arranged, and the liquid crystal layer is arranged described Between first substrate and the second substrate, the liquid crystal layer includes multiple liquid crystal molecules；

The display screen provides a user display picture, the light sensation far from the side of the second substrate in the first substrate Side of the liquid crystal layer far from the first substrate is arranged in element；

The driving method includes:

The backlight module stops providing backlight to the display screen, and the first substrate and the second substrate stop driving The liquid crystal molecule rotation in the liquid crystal layer is moved, the display screen is in breath screen state；

The light sensation driving assembly drives the liquid crystal molecule in the liquid crystal layer to rotate, so that the light of the light sensitive component can It is transmitted in the liquid crystal layer.

12. driving method according to claim 11, which is characterized in that the driving method further include:

The backlight module provides backlight to the display screen, and the first substrate and the second substrate drive the liquid Liquid crystal molecule rotation in crystal layer, the display screen are in bright screen state.