CN114942553B

CN114942553B - Display substrate, control method thereof and display device

Info

Publication number: CN114942553B
Application number: CN202210563141.9A
Authority: CN
Inventors: 马勇; 谷新; 康昭; 李树磊; 赵承潭; 谢昌翰; 黄华; 张宜驰
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2022-05-18
Filing date: 2022-05-18
Publication date: 2023-11-14
Anticipated expiration: 2042-05-18
Also published as: CN114942553A

Abstract

The application provides a display substrate, a control method thereof and a display device. The display substrate comprises a substrate and a plurality of pixel units arranged in an array on the substrate, wherein the pixel units comprise a reflecting layer arranged on the substrate and are configured to: reflecting the light; a first dimming layer disposed on the reflective layer configured to: switching between a transparent state and a first color state under voltage control to adjust light passing through the first dimming layer; a second dimming layer disposed on the first dimming layer configured to: switching between a transparent state and a second color state under voltage control to adjust light passing through the second dimming layer. According to the application, gray scale display is realized by adjusting the transmitted light through the dimming layers in the pixel units.

Description

Display substrate, control method thereof and display device

Technical Field

The present application relates to the technical field of display substrates, and particularly to a display substrate, a control method thereof, and a display device.

Background

One possible steady state display technique in the related art is to implement a bi-state using an electrophoretic technique. The principle is that positive and negative charges are introduced into the display panel, and the display medium is charged, so that the principle of positive and negative attraction is utilized to move between the upper panel and the lower panel by means of the dielectric medium suspended in the solution, thereby realizing the conversion between a dark state and a bright state. Since the dielectric must be moved under the control of the voltage, steady state cannot be achieved once the voltage is removed.

Disclosure of Invention

In view of the above, the present application provides a display substrate, a control method thereof and a display device capable of implementing bistable reflection to a certain extent, so as to solve or partially solve the problem of unstable display.

As one aspect of the present application, there is provided a display substrate including a substrate and a plurality of pixel units arranged in an array disposed on the substrate, wherein the pixel units include:

a reflective layer disposed on the substrate base configured to: reflecting the light;

a first dimming layer disposed on the reflective layer configured to: switching between a transparent state and a first color state under voltage control to adjust light passing through the first dimming layer; and

a second dimming layer disposed on the first dimming layer configured to: switching between a transparent state and a second color state under voltage control to adjust light passing through the second dimming layer.

Optionally, at least one of the first dimming layer and the second dimming layer includes a first electrode layer, an electrochromic layer and a second electrode layer which are stacked;

the electrochromic layer is configured to: switching between a transparent state and a color state is performed under control of a voltage supplied by the first electrode layer and the second electrode layer.

Optionally, the electrochromic layer includes a metal organic framework compound.

Optionally, the display substrate further includes:

and a dielectric layer disposed between the first dimming layer and the second dimming layer.

Optionally, the first electrode layer and the second electrode layer are transparent electrode layers, and the dielectric layer is a transparent dielectric layer.

Optionally, the first color state is a red state, and the second color state is a green state.

Optionally, the reflective layer includes:

a lens structure disposed on the substrate; and

and the metal reflecting layer is arranged on the surface of the lens structure.

Optionally, a light blocking layer is disposed between adjacent pixel units.

Optionally, the display substrate further includes:

a third dimming layer disposed on the second dimming layer configured to: switching between a transparent state and a third color state under voltage control to adjust light passing through the third dimming layer.

Optionally, the third color state is a blue color state.

As a second aspect of the present application, there is provided a display device including the above display substrate provided by the present application.

As a third aspect of the present application, there is provided a control method of a display substrate, comprising:

determining a target pixel unit in the display substrate and a target gray scale value of the target pixel unit;

determining a first voltage and a second voltage corresponding to the first dimming layer and the second dimming layer of the target pixel unit according to the target gray scale value; and

and respectively controlling the color states of the first dimming layer and the second dimming layer by using the first voltage and the second voltage so as to adjust the light rays emitted by the display substrate.

Optionally, when the target pixel unit includes a third dimming layer, the control method further includes:

determining a third voltage corresponding to the third dimming layer of the target pixel unit according to the target gray scale value; and

and controlling the color state of the third dimming layer by using the third voltage so as to adjust the light emitted by the display substrate.

As can be seen from the above, the display substrate, the control method thereof and the display device provided by the application realize bistable states of bright state and dark state by controlling the color of the dimming layer.

Drawings

In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1A is a schematic diagram of an electronic paper electrophoresis technology.

Fig. 1B is a schematic view of a display substrate for bistable display by means of single particles.

FIG. 1C is a schematic diagram of a single particle display substrate in a dark state.

Fig. 1D is a schematic view of a single particle display substrate in a bright state.

Fig. 2A is a schematic diagram of an exemplary display substrate according to an embodiment of the present application.

FIG. 2B is a graph of the ultraviolet-visible spectrum of MOFs material at variable pressure.

Fig. 3A is a schematic diagram of an exemplary reflective layer structure according to an embodiment of the present application.

Fig. 3B is a schematic diagram of exemplary lens structure dimensions according to an embodiment of the application.

FIG. 3C is a diagram illustrating the reflection angle and brightness of the reflective layer.

Fig. 4 is a schematic diagram of an exemplary display substrate according to an embodiment of the present application.

Fig. 5 is a schematic diagram of another exemplary display substrate according to an embodiment of the present application.

Fig. 6 is a flowchart illustrating an exemplary display substrate control method according to an embodiment of the present application.

Detailed Description

The present application will be further described in detail below with reference to specific embodiments and with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present application more apparent.

It should be noted that unless otherwise defined, technical or scientific terms used in the embodiments of the present application should be given the ordinary meaning as understood by one of ordinary skill in the art to which the present application belongs. The terms "first," "second," and the like, as used herein, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.

The ultrathin, ultralight and soft characteristics of the electronic paper can make the electronic product rich in aesthetic feeling and visual shock, and various reflective display technologies with bistable characteristics are mainly used in the research of the practical technology with the characteristics of the electronic paper, and common types include electrophoretic display, spin ball display, bistable liquid crystal, electrowetting display, fast response electronic powder fluid display and other technologies, wherein the electrophoretic display technology is most rapidly developed.

The electronic paper mainly comprises a surface layer, a bottom layer and a middle layer, wherein tens of thousands of tiny ink particles are distributed in a transparent base solution to form a suspension system, the diameter of each ink particle is about 100 mu m, the surface of each ink particle is easy to absorb charges, and the particles capable of inducing charges can move under the action of an external electric field. The electronic particles are suspended in the pigment, uniformly arranged and randomly move and are jointly wrapped by the transparent capsule shell, under the action of an external electric field, the white particles can induce charges to move in different directions, one face of the white particles, which is gathered, can display white, and the other face of the white particles, which is gathered, displays the color of the dye, namely black, as shown in fig. 1A, and the electronic paper realizes the color conversion of characters and images by utilizing the principle.

In the light of this technology, the display principle has been developed to realize black-and-white display by means of black particles alone. Fig. 1B shows a schematic structure of an exemplary display substrate 100. The display substrate 100 may include a color film substrate, an array substrate, and ink particles 110 interposed between the color film substrate and the array substrate, and may be sealed with a frame sealing adhesive 106. The color film substrate may further include a substrate 102 and a color film layer 114 disposed on the substrate 102, and a lens structure 112 may be further disposed on the color film layer 114. The array substrate may further include a substrate 102 and a TFT array 104 disposed on the substrate 102. The display substrate 100 may include a plurality of pixel units disposed between the upper and lower substrates 102, and a barrier layer 108 may be disposed between the plurality of pixel units. The mechanism of action in which the display is by means of ink particles (the colour of which may be black, for example) is: under normal unpowered conditions, the ink particles 110 are suspended in the solution, and the device as a whole shows neither a bright nor a dark state; dark state display mechanism: the color film substrate is applied with a voltage opposite to that of the array substrate, the ink particles 110 start to move under the action of the electric field force, and the electric field force is large enough to enable the ink particles 110 to climb on the surface of the lens structure 112, as shown in fig. 1C, so that ambient light is incident into the lens structure and absorbed by the attached ink particles, and the ambient light cannot be reflected to human eyes to present a dark state; bright state display mechanism: the direction of the electric field is reversed and the ink particles 110 begin to move away from the lens surface toward the lower substrate. The lens surface is contacted with solute in the solution, and light is totally reflected on the lens surface, as shown in fig. 1D, and the lens surface is in a bright state.

Since the display substrate 100 can realize bright and dark dual-state display only by means of the continuous electric field effect, the display substrate is easily interfered by the environment and the power consumption of the display is greatly increased. Is not well suited for development of energy conservation. Moreover, for some markets, outdoor power replacement and power line introduction are inconvenient, and steady state cannot be achieved, so bistable display is more important.

In view of the above problems, the embodiments of the present application provide a display substrate, a control method thereof, and a display device, which are different from the conventional electrophoresis technology in that a continuous electric field is required to control, and the display substrate of the embodiments of the present application can still maintain stability after removing an electric signal, so that bistable states of a bright state and a dark state can be realized.

Fig. 2A shows a schematic diagram of an exemplary display substrate 200 provided by an embodiment of the application.

As shown in fig. 2A, the display substrate 200 may include a substrate 202 and a plurality of pixel units, e.g., pixel units 204A, 204B, disposed on the substrate 202. In some embodiments, a plurality of pixel units may be arranged in an array.

In some embodiments, as shown in fig. 2A, taking the pixel unit 204A as an example, the pixel unit may further include a reflective layer 206, a first dimming layer 208, and a second dimming layer 210 sequentially stacked on the substrate base 202. Wherein the reflective layer 206 may be used to reflect light (e.g., ambient light), the first dimming layer 208 may be used to switch between a transparent state and a first color state (e.g., red state) under voltage control to adjust the color or transmittance of light passing through the first dimming layer 208, and the second dimming layer 210 may be used to switch between a transparent state and a second color state (e.g., green state) under voltage control to adjust the color or transmittance of light passing through the second dimming layer 210.

In some embodiments, the display substrate 200 may implement a reflective display. As shown in fig. 2A, the ambient light may be incident on the display substrate 200 along an incident direction 212, wherein the second dimming layer 210 may be in a transparent state or a second color state under voltage control, such that the ambient light may be unchanged or changed into a light having the second color after passing through the second dimming layer 210. Next, the first dimming layer 208 may assume a transparent state or a first color state under voltage control, such that light after passing through the second dimming layer 210 may be light with no change or superposition of the first color after passing through the first dimming layer 208. For example, taking the first color as red and the second color as green as an example, assuming that the first dimming layer 208 is in the first color state, the second dimming layer 210 is in the second color state, and the transmittance of the first dimming layer 208 and the second dimming layer 210 are the same, ambient light will be completely absorbed after passing through the first dimming layer 208 and the second dimming layer 210 and then the corresponding pixel unit will take on a black state, and when both the first dimming layer 208 and the second dimming layer 210 are in the transparent state, ambient light may be reflected by the reflective layer 206 after passing through the first dimming layer 208 and the second dimming layer 210, and then take on a white state. By adjusting the transmittance of the first dimming layer 208 and the second dimming layer 210 by adjusting the voltages thereof, the gray scale of the corresponding pixel unit can be realized.

In some embodiments, the first dimming layer 208 and the second dimming layer 210 may be electrochromic structures. As shown in fig. 2A, the first dimming layer 208 may include a first electrode layer 2082, an electrochromic layer 2084, and a second electrode layer 2086 that are stacked. The electrochromic layer 2084 may switch between a transparent state and a first color state under control of voltages provided by the first and second electrode layers 2082, 2086. Similarly, the second dimming layer 210 may include a first electrode layer 2102, an electrochromic layer 2104, and a second electrode layer 2106 which are stacked. The electrochromic layer 2104 may be switched between a transparent state and a second color state under control of a voltage provided by the first electrode layer 2102 and the second electrode layer 2106.

As an alternative example, the electrochromic layers 2084, 2104 may include metal organic framework compounds (MOFs). The material is a material obtained by embedding a color-changing organic compound naphthalimide into a metal-organic framework material (MOF-74) with channels. The material presents transparent color when no voltage is applied, can quickly realize the color conversion from transparent state to dark state under different voltages, and can keep the dark state unchanged after the voltage is removed. For example, the material may appear red when a voltage of-1.6V is applied and green when a voltage of-2.3V is applied; the transparent state can be recovered from the dark state when the voltage of-0.7 to-0.5V is reapplied in the dark state, and the transparent state is unchanged after the voltage is removed.

Fig. 2B shows a graph of absorbance (absorptance) versus wavelength (wavelength) of a metal-organic framework compound under voltage control according to an embodiment of the present application. The left graph a in fig. 2B corresponds to the absorbance of the metal-organic framework compound for each wavelength of light at the cathode bias (cathode bias), and the right graph B in fig. 2B corresponds to the absorbance of the metal-organic framework compound for each wavelength of light at the anode bias (anode bias). Taking the embodiment of the graph A with the electrode pressing being-2V as an example and the embodiment of the graph B with the electrode pressing being-0.5V as an example, it can be seen that the color change material has higher light absorption degree under the cathode bias and lower light absorption degree under the anode bias, which means that the color of the color change material can be changed by voltage control, and the gray scale can be adjusted under more proper voltage control.

In some embodiments, as shown in fig. 2A, the display substrate 200 may further include a dielectric layer 214 disposed between the first dimming layer 208 and the second dimming layer 210. Because the voltages required for electrochromic layers 2104 and 2084 in different dark states may be different, when electrode layer 2102 is adjacent to electrode layer 2086, capacitance may form between the two and thus result in signal crosstalk, and thus dielectric layer 214 may be disposed between electrode layer 2102 and electrode layer 2086, thereby reducing the effects between adjacent electrode layers. To better avoid signal crosstalk problems, the dielectric constant of the dielectric layer 214 needs to be set higher, for example, a dielectric material with a dielectric constant greater than 3.7 may be selected.

In some embodiments, electrode layers 2106, 2102, 2086, and 2082 may be transparent electrode layers, for example, ITO may be used; the dielectric layer 214 may be a transparent dielectric layer, so as to improve transmittance and light efficiency.

To better reflect light, in some embodiments, the reflective layer 206 may have some special designs. Fig. 3A shows a schematic diagram of an exemplary reflective layer 206, according to an embodiment of the application.

In some embodiments, as in fig. 3A, the reflective layer may be composed of a LENs structure (LENs structure) 2602 disposed on the substrate base, and a metal reflective layer 2604 disposed on the LENs structure. Ambient light is reflected off of the reflective layer 206 as it is incident in direction 212 through the first dimming layer 208 and the second dimming layer 210. The LENs structure 2602 may be formed by a plurality of Lenses (LENs) arranged in an array, and may have a lambertian reflection function, so that the reflected light may be more uniform.

As an alternative embodiment, as shown in fig. 3A, a metal reflective layer 2604 may be applied to the LENs structure 2602 by nanoimprinting or thermal reflow plating, and planarized with a transparent organic material (OC) 2606 on the surface. Fig. 3B shows an exemplary lens structure size schematic in accordance with an embodiment of the application. As shown in fig. 3B, the lenses have a height H and a diameter D, the lenses have a pitch P therebetween, and the metal reflective layer has a thickness H. Wherein the lens height H may be 1 to 2 μm, the lens diameter D may be 3 to 5 μm, the lens pitch P may be 4 to 6 μm, and the thickness H of the metal reflective layer 2604 may be 0.3 to 0.5 μm. As an alternative embodiment, the lens height H may be 1.1 μm, the lens diameter D may be 4.01 μm, the lens pitch P may be 5.0 μm, and the thickness H of the metal reflective layer 2604 may be 0.35 μm. In this embodiment, experiments prove that (i.e., the size of the receiver is consistent with that of the light source), when the light source is covered with 5*5, 10×10 and 20×20 lenses, respectively, as shown in fig. 3C, the brightness of the light reflected in the reflective layer at different reflection angles is not greatly different, which indicates that the light reflected by the reflective structure is relatively uniform.

In some embodiments, a light blocking layer may also be disposed between adjacent pixel cells. Fig. 4 shows a schematic diagram of another exemplary display substrate 200 according to an embodiment of the application. As shown in fig. 4, taking the pixel units 204A and 204B as an example, in order to prevent the pixel units 204A and 204B from cross-color each other, a light blocking layer 216 is disposed therebetween. In some embodiments, the barrier layer is black. In some embodiments, the light blocking layer 216 in the display substrate 200 may be formed as a Black Matrix (BM).

As an implementation, the dark state principle of the display substrate 200 may be: when the first dimming layer and the second dimming layer are controlled by the electrode layer to be respectively in a red state and a green state, ambient light cannot penetrate through the pixel units on the substrate and is in a dark state due to the fact that the red and the green are overlapped to be black. The principle of the bright state may be: when the first light modulation layer and the second light modulation layer are both transparent, ambient light is reflected out of the reflecting layer through the pixel units on the substrate and presents a bright state. The materials selected in the embodiment of the application still keep the state unchanged after the voltage is removed, so that bistable reflective display can be realized.

Fig. 5 shows a schematic diagram of yet another exemplary display substrate 200 provided by an embodiment of the present application. As shown in fig. 5, in some embodiments, the display substrate 200 may further include a third dimming layer 218. The third dimming layer 218 may further include a first electrode layer 2186, an electrochromic layer 2184, and a second electrode layer 2182 that are stacked, and the electrochromic layer 2184 may be switched between a transparent state and a third color state (e.g., blue) under control of the first electrode layer 2186 and the second electrode layer 2182 to adjust the color or transmittance of light passing through the third dimming layer 218. Thus, when the first dimming layer 208, the second dimming layer 210 and the third dimming layer 218 are respectively configured to be switchable between a transparent state or a red state, a green state and a blue state, the combination of the three can further realize color adjustment, so that the display substrate 200 can realize color display.

It is understood that the third dimming layer 218 may not be made of MOFs material. As an alternative embodiment, WO may be included in electrochromic layer 2184 ₃ Or MoO ₃ An isoelectric material.

In some embodiments, the display substrate 200 may further include a dielectric layer 220 disposed between the second dimming layer 210 and the third dimming layer 218 to reduce signal crosstalk between adjacent electrodes of the second dimming layer 210 and the third dimming layer 218. As an alternative embodiment, to better avoid the signal crosstalk problem, the dielectric constant of the dielectric layer 214 needs to be set higher, for example, a dielectric material with a dielectric constant greater than 3.7 may be selected.

The embodiment of the present application further provides a display device, which includes any embodiment of the display substrate 200, and the arrangement and combination of the embodiments, and has the technical effects of the corresponding embodiment of the display substrate, which are not described herein again.

The display device may be a product having an image display function, and may be, for example: displays, televisions, billboards, digital photo frames, laser printers with display functions, telephones, mobile phones, personal digital assistants (Personal Digital Assistant, PDAs), digital cameras, portable video cameras, viewfinders, navigators, vehicles, large-area walls, home appliances, information query devices (e.g., business query devices for e-government, banking, hospitals, power departments, monitors, etc.).

The embodiment of the application also provides a control method of the display substrate. Fig. 6 shows a flow diagram of an exemplary control method 300 provided by an embodiment of the present application. The method 300 may be used to control the display substrate 200 and may further include the following steps.

In step 302, a target pixel cell in the display substrate and a target gray scale value for the target pixel cell may be determined.

Specifically, in this step, the gray-scale value of each pixel unit in the display substrate may be determined according to the screen to be displayed by the display substrate.

In step 304, a first voltage and a second voltage corresponding to the first dimming layer and the second dimming layer of the target pixel unit may be determined according to the target gray scale value.

Based on the foregoing, the dimming layer can switch between the color state and the transparent state under the voltage control, so that the voltage corresponding to the corresponding gray scale value and used for controlling the dimming layer, that is, the first voltage and the second voltage corresponding to the first dimming layer and the second dimming layer, can be determined according to the rule of the voltage required from the color state to the transparent state of the dimming layer.

In step 306, the first voltage and the second voltage may be used to control the color states of the first dimming layer and the second dimming layer, respectively, so as to adjust the light emitted from the display substrate.

Thus, by controlling each pixel unit of the display substrate by the above method, the display of the target display screen can be realized.

In some embodiments, the first and second dimming layers may include metal-organic framework compounds (MOFs) such that when the first and second dimming layers are voltage controlled to appear in a certain color state, the state may be maintained when the voltage is removed, and thus device power consumption may be reduced. Thus, in some embodiments, the method 300 may further comprise, after step 306: the first voltage and the second voltage are removed, thereby saving power consumption.

In some embodiments, when the target pixel unit includes a third dimming layer, the control method 300 may further include the steps of:

In this way, by introducing the third dimming layer, control of full-color display of the display substrate 200 can be achieved.

Those of ordinary skill in the art will appreciate that: the discussion of any of the embodiments above is merely exemplary and is not intended to suggest that the scope of the application (including the claims) is limited to these examples; the technical features of the above embodiments or in the different embodiments may also be combined within the idea of the application, the steps may be implemented in any order and there are many other variations of the different aspects of the application as described above, which are not provided in detail for the sake of brevity.

The embodiments of the application are intended to embrace all such alternatives, modifications and variances which fall within the broad scope of the appended claims. Therefore, any omission, modification, equivalent replacement, improvement, etc. of the present application should be included in the scope of the present application.

Claims

1. A display substrate characterized by comprising a substrate and a plurality of pixel units arranged in an array on the substrate, wherein the pixel units comprise:

a second dimming layer disposed on the first dimming layer configured to: switching between a transparent state and a second color state under voltage control to adjust light passing through the second dimming layer;

wherein at least one of the first dimming layer and the second dimming layer comprises a first electrode layer, an electrochromic layer and a second electrode layer which are stacked;

2. The display substrate of claim 1, wherein the electrochromic layer comprises a metal-organic backbone compound.

3. The display substrate of claim 1, wherein the display substrate further comprises:

4. A display substrate according to claim 3, wherein the first electrode layer and the second electrode layer are transparent electrode layers and the dielectric layer is a transparent dielectric layer.

5. The display substrate of claim 1, wherein the first color state is a red state and the second color state is a green state.

6. The display substrate of claim 1, wherein the reflective layer comprises:

a lens structure disposed on the substrate; and

7. The display substrate according to claim 1, wherein a light blocking layer is disposed between adjacent ones of the pixel units.

8. The display substrate according to any one of claims 1 to 7, further comprising:

9. The display substrate of claim 8, wherein the third color state is a blue color state.

10. A display device comprising a display substrate according to any one of claims 1-9.

11. A control method of the display substrate according to any one of claims 1 to 9, comprising:

12. The control method of claim 11, wherein when the target pixel cell includes a third dimming layer, the control method further comprises: