Display panel, preparation method thereof and display device

Abstract

The embodiment of the invention provides a display panel, a preparation method thereof and a display device. The display panel comprises a substrate, a pixel light-emitting layer, a packaging layer and a photochromic layer, the pixel light-emitting layer is arranged on the substrate, the photochromic layer is arranged on the side, away from the substrate, of the pixel light-emitting layer, and the packaging layer is arranged between the pixel light-emitting layer and the photochromic layer; a plurality of first light-emitting units are arranged in the pixel light-emitting layer, and the first light-emitting units are connected with a first driving circuit on the substrate; the first driving circuit is used for driving the first light-emitting unit to emit write-in light; the area, irradiated by the write-in light, on the photochromic layer changes in color to form a color developing area and keeps the color developing area, the color of the color developing area is different from that of a primary color area, not irradiated by the write-in light, on the photochromic layer, and the color of the color developing area changes to be the same as that of the primary color area after being irradiated by the erase light; and the color of the color developing area is kept unchanged before being irradiated by the erasing light.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of display technology, and in particular, to a display panel and a method for preparing the same, and a display device. Background Art

[0002] Organic Light Emitting Diodes (OLED) and flat panel display devices based on technologies such as Light Emitting Diodes (LED) have been widely used in various consumer electronic products such as mobile phones, televisions, laptops, desktop computers, etc. due to their advantages such as high image quality, power saving, thin body and wide application range, becoming the mainstream in display devices.

[0003] However, the power consumption of current display devices such as OLED needs to be reduced. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a new display panel to at least partially solve the above problems.

[0005] According to a first aspect of an embodiment of the present application, a display panel is provided, comprising: a substrate, a pixel light-emitting layer, an encapsulation layer and a photochromic layer; the pixel light-emitting layer is arranged on the substrate, the photochromic layer is arranged on a side of the pixel light-emitting layer away from the substrate, and the encapsulation layer is arranged between the pixel light-emitting layer and the photochromic layer; a plurality of first light-emitting units are arranged in the pixel light-emitting layer, and the first light-emitting units are connected to a first driving circuit on the substrate; the first driving circuit is used to drive the first light-emitting units to emit writing light; the area on the photochromic layer irradiated by the writing light changes color to form a color development area and maintains the color, the color of the color development area is different from the color of the primary color area on the photochromic layer that is not irradiated by the writing light, wherein the color of the color development area changes to the same color as the primary color area after being irradiated by the erasing light, and the color of the color development area remains unchanged before being irradiated by the erasing light.

[0006] In some optional embodiments, the display panel further includes a second light emitting unit for emitting erasing light, and the second light emitting unit is disposed on a side of the photochromic layer close to the base substrate.

[0007] In some optional embodiments, the display panel includes a plurality of the second light-emitting units, and the plurality of the second light-emitting units are located in the pixel light-emitting layer; and the orthographic projection of each of the first light-emitting units on the photochromic layer is adjacent to the orthographic projection of at least one of the second light-emitting units on the photochromic layer.

[0008] In some optional embodiments, the second light emitting unit is disposed on a side of the first light emitting unit away from the substrate, and at least a portion of an orthographic projection of the second light emitting unit on the photochromic layer intersects with an orthographic projection of the first light emitting unit on the photochromic layer;

[0009] In some optional embodiments, along the thickness direction of the display panel, the second light emitting unit is spaced apart from the first light emitting unit, and the orthographic projection of the first light emitting unit on the photochromic layer is located within the orthographic projection of the second light emitting unit on the photochromic layer.

[0010] In some optional embodiments, the second light-emitting unit is disposed between the pixel light-emitting layer and the photochromic layer; and the encapsulation layer includes a first encapsulation layer and a second encapsulation layer, the first encapsulation layer is disposed between the pixel light-emitting layer and the second light-emitting unit, and the second encapsulation layer is disposed between the second light-emitting unit and the photochromic layer.

[0011] In some optional embodiments, the encapsulation layer further includes a first inkjet-printed encapsulation layer; the first inkjet-printed encapsulation layer is located between the first encapsulation layer and the second light-emitting unit, or the first inkjet-printed encapsulation layer is located between the second light-emitting unit and the second encapsulation layer.

[0012] In some optional embodiments, the encapsulation layer further includes a second inkjet-printed encapsulation layer and a third encapsulation layer; when the first inkjet-printed encapsulation layer is located between the first encapsulation layer and the second light-emitting unit, the second inkjet-printed encapsulation layer is arranged on a side of the second encapsulation layer close to the photochromic layer, and the third encapsulation layer is arranged between the second inkjet-printed encapsulation layer and the photochromic layer.

[0013] In some optional embodiments, the second light-emitting unit is arranged on a side of the first light-emitting unit away from the base substrate, the second light-emitting unit is adjacent to the first light-emitting unit, and the orthographic projection of the second light-emitting unit on the photochromic layer coincides with the orthographic projection of the first light-emitting unit on the photochromic layer.

[0014] In some optional embodiments, the display panel further includes a third light emitting unit; the third light emitting unit is configured to emit the erasing light toward the photochromic layer at a side of the photochromic layer away from the base substrate.

[0015] In some optional embodiments, the photochromic layer includes a plurality of sub-chromic layers stacked along the thickness direction of the display panel, and the color development area on the photochromic layer includes a sub-color development area on the sub-chromic layer; the first light-emitting unit includes a plurality of first sub-light-emitting units, and the first sub-light-emitting units correspond to the sub-chromic layers one by one; the first sub-light-emitting units are used to emit the writing light, and the wavelength of the writing light emitted by each of the first sub-light-emitting units is different; the area on the sub-chromic layer irradiated by the writing light of the corresponding first sub-light-emitting unit undergoes color change to form the sub-color development area, and the color of the sub-color development area formed on each of the sub-chromic layers is different.

[0016] According to a second aspect of an embodiment of the present application, a method for preparing a display panel is provided, the method comprising: forming a pixel light-emitting layer on one side of a substrate; forming an encapsulation layer on a side of the pixel light-emitting layer away from the substrate; forming a photochromic layer on a side of the encapsulation layer away from the pixel light-emitting layer; wherein a plurality of first light-emitting units are arranged in the pixel light-emitting layer, and the first light-emitting units are connected to a first driving circuit on the substrate; the first driving circuit is used to drive the first light-emitting units to emit writing light; the area on the photochromic layer irradiated by the writing light changes color to form a color development area and maintains the color, the color of the color development area is different from the color of the primary color area on the photochromic layer that is not irradiated by the writing light, the color of the color development area changes to the same color as the primary color area after being irradiated by the erasing light, and the color of the color development area remains unchanged before being irradiated by the erasing light.

[0017] In some optional embodiments, a second light emitting unit is formed on a side of the base substrate where the pixel light emitting layer is disposed.

[0018] In some optional embodiments, forming a second light-emitting unit on a side of the base substrate where the pixel light-emitting layer is provided includes: forming a plurality of the second light-emitting units on the pixel light-emitting layer; wherein the orthographic projection of each of the first light-emitting units on the photochromic layer is adjacent to the orthographic projection of at least one of the second light-emitting units on the photochromic layer.

[0019] In some optional embodiments, forming the second light-emitting unit on the side of the base substrate where the pixel light-emitting layer is provided comprises: forming the second light-emitting unit on the side of the first light-emitting unit away from the base substrate; wherein at least a portion of the orthographic projection of the second light-emitting unit on the photochromic layer intersects with the orthographic projection of the first light-emitting unit on the photochromic layer;

[0020] In some optional embodiments, forming an encapsulation layer on a side of the pixel light-emitting layer away from the substrate substrate includes: forming a first encapsulation layer on a side of the pixel light-emitting layer away from the substrate substrate; forming the second light-emitting unit on a side of the first light-emitting unit away from the substrate substrate includes: forming the second light-emitting unit on a side of the first encapsulation layer away from the pixel light-emitting layer; forming an encapsulation layer on a side of the pixel light-emitting layer away from the substrate substrate also includes: forming a second encapsulation layer on a side of the second light-emitting unit away from the first encapsulation layer;

[0021] In some optional embodiments, the orthographic projection of the first light-emitting unit on the photochromic layer is located within the orthographic projection of the second light-emitting unit on the photochromic layer;

[0022] In some optional embodiments, forming the encapsulation layer on the side of the pixel light-emitting layer away from the base substrate further comprises: forming a first inkjet-printed encapsulation layer on the side of the first encapsulation layer away from the pixel light-emitting layer, so that the first inkjet-printed encapsulation layer is located between the first encapsulation layer and the second light-emitting unit, or forming a first inkjet-printed encapsulation layer on the side of the second light-emitting unit away from the first encapsulation layer, so that the first inkjet-printed encapsulation layer is located between the second light-emitting unit and the second encapsulation layer;

[0023] In some optional embodiments, forming an encapsulation layer on a side of the pixel light-emitting layer facing away from the substrate further includes: forming a first inkjet-printed encapsulation layer on a side of the first encapsulation layer facing away from the pixel light-emitting layer, forming a second inkjet-printed encapsulation layer on a side of the second encapsulation layer facing away from the second light-emitting unit, and forming a third encapsulation layer on a side of the second inkjet-printed encapsulation layer facing away from the second encapsulation layer, so that the third encapsulation layer is located between the second inkjet-printed encapsulation layer and the photochromic layer.

[0024] According to a third aspect of an embodiment of the present application, a display device is provided, comprising the display panel described in the above embodiment.

[0025] In an embodiment of the present application, the display panel includes a substrate, a pixel light-emitting layer, an encapsulation layer and a photochromic layer. The pixel light-emitting layer is arranged on the substrate, the photochromic layer is arranged on the side of the pixel light-emitting layer away from the substrate, and the encapsulation layer is arranged between the pixel light-emitting layer and the photochromic layer. A plurality of first light-emitting units are arranged in the pixel light-emitting layer, and the first light-emitting unit is connected to a first driving circuit on the substrate; the first driving circuit is used to drive the first light-emitting unit to emit writing light. The area on the photochromic layer irradiated by the writing light changes color to form a color development area, and the color of the color development area is different from the color of the primary color area on the photochromic layer that is not irradiated by the writing light, wherein the color of the color development area changes to the same color as the primary color area after being irradiated by the erasing light, and the color of the color development area remains unchanged before being irradiated by the erasing light. By controlling a plurality of first light-emitting units to emit writing light, a color development area corresponding to a predetermined pattern composed of a plurality of first light-emitting units can be formed on the photochromic layer, thereby realizing the display of the predetermined pattern. After the display area of ​​the predetermined pattern is formed on the photochromic layer, the first light-emitting unit can be turned off, and the predetermined pattern can be displayed only by reflecting the ambient light through the display area without consuming electric energy, which can significantly reduce the power consumption of the display panel. In particular, in the scene where the predetermined pattern needs to be displayed continuously, the predetermined pattern can be displayed by using the continuously existing display area, which can greatly save electric energy, so that the average power consumption of the display panel can even be reduced to near zero. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0027] Figure 1 A schematic diagram of the cross-sectional structure of a partial area of ​​a display panel provided in an optional embodiment of the present application.

[0028] Figure 2 Provided for optional embodiments of this application Figure 1 Schematic diagram of the display panel with writing light irradiation.

[0029] Figure 3 Provided for optional embodiments of this application Figure 1 Schematic diagram of erasing light irradiation in a display panel.

[0030] Figure 4 A schematic cross-sectional structure diagram of a first light-emitting unit provided in an optional embodiment of the present application.

[0031] Figure 5 A schematic diagram of the cross-sectional structure of a partial area in another display panel provided in an optional embodiment of the present application.

[0032] Figure 6 Provided for optional embodiments of this application Figure 5 Schematic diagram of the display panel with writing light irradiation.

[0033] Figure 7 Provided for optional embodiments of this application Figure 5 Schematic diagram of erasing light irradiation in a display panel.

[0034] Figure 8 A schematic cross-sectional view of a packaging layer structure provided for an optional embodiment of the present application.

[0035] Fig. 9 A schematic cross-sectional view of the structure of another packaging layer provided for an optional embodiment of the present application.

[0036] Fig.10 A schematic cross-sectional view of a structure of another encapsulation layer provided for an optional embodiment of the present application.

[0037] Fig.11 A schematic diagram of the cross-sectional structure of a partial area in another display panel provided as an optional embodiment of the present application.

[0038] Fig.12 Provided for optional embodiments of this application Fig.11 Schematic diagram of the display panel with writing light irradiation.

[0039] Fig.13 Provided for optional embodiments of this application Fig.11 Schematic diagram of erasing light irradiation in a display panel.

[0040] Fig.14 A schematic flow chart of a method for preparing a display panel provided in an optional embodiment of the present application.

[0041] Reference numerals:

[0042] 100, display panel; 110, base substrate; 111, first driving circuit; 112, second driving circuit; 120, pixel light-emitting layer; 130, encapsulation layer; 131, first encapsulation layer; 132, second encapsulation layer; 133, third encapsulation layer; 134, first inkjet printing encapsulation layer; 135, second inkjet printing encapsulation layer; 140, photochromic layer; 141, color development area; 150, first light-emitting unit; 151, first anode layer; 152, first hole injection layer; 153, first hole transport layer; 154, first light-emitting layer; 155, first electron transport layer; 156, first electron injection layer; 157, first cathode layer; 158, writing light; 160, second light-emitting unit; 161, second anode layer; 162, second light-emitting layer; 163, erasing light. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, 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. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the embodiments of the present application should fall within the scope of protection of the embodiments of the present application.

[0044] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "an" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0045] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0046] According to a first aspect of an embodiment of the present application, a display panel is provided to solve the above-mentioned problem.

[0047] Figure 1-3 FIG. 1 shows a schematic diagram of the structure of a display panel 100. Figure 1-3 As shown, the display panel 100 includes: a base substrate 110 , a pixel light emitting layer 120 , an encapsulation layer 130 and a photochromic layer 140 .

[0048] The pixel light emitting layer 120 is disposed on the base substrate 110, the photochromic layer 140 is disposed on the side of the pixel light emitting layer 120 away from the base substrate 110, and the encapsulation layer 130 is disposed between the pixel light emitting layer 120 and the photochromic layer 140. The encapsulation layer 130 may include a transparent insulating material, which may be used to encapsulate the pixel light emitting layer 120 and isolate the pixel light emitting layer 120 from the photochromic layer 140.

[0049] A plurality of first light-emitting units 150 are provided in the pixel light-emitting layer 120, and the first light-emitting units 150 are connected to the first driving circuit 111 on the base substrate 110; the first driving circuit 111 is used to drive the first light-emitting units 150 to emit writing light. The first light-emitting units 150 may be pixel units of OLED or Micro-LED, so that each first light-emitting unit 150 may be controlled to emit light individually, thereby flexibly controlling the color change on the photochromic layer 140.

[0050] For example, Figure 4 As shown, the first light-emitting unit 150 may specifically include a first anode layer 151, a first hole injection layer 152, a first hole transport layer 153, a first light-emitting layer 154, a first electron transport layer 155, a first electron injection layer 156 and a first cathode layer 157, etc. The first anode layer 151 is adjacent to the substrate 110 and connected to the first driving circuit 111 on the substrate 110; the first hole injection layer 152 can be located on the side of the anode away from the substrate 110; the first hole transport layer 153 can be located on the side of the first hole injection layer 152 away from the substrate 110; the first light-emitting layer 154 can be located on the side of the first hole transport layer 153 away from the substrate 110; the first electron transport layer 155 can be located on the side of the first light-emitting layer 154 away from the substrate 110; the first electron injection layer 156 can be located on the side of the first electron transport layer 155 away from the substrate 110; and the first cathode layer 157 can be located on the side of the first electron injection layer 156 away from the substrate 110. Figure 2 As shown, the driving circuit on the base substrate 110 can make the first light-emitting layer 154 between the first anode layer 151 and the first cathode layer 157 of the first light-emitting unit 150 emit writing light 158 ​​by applying a driving signal to the first anode layer 151 of the first light-emitting unit 150 .

[0051] like Figure 2 As shown, the area on the photochromic layer 140 irradiated by the writing light 158 ​​changes color to form a color development area 141 and maintains the color of the color development area 141. The color of the color development area 141 is different from the color of the primary color area on the photochromic layer 140 that is not irradiated by the writing light 158. Figure 3 As shown, the color of the color-developing area 141 changes to the same color as the primary color area after being irradiated by the erasing light 163, and the color of the color-developing area 141 remains unchanged before being irradiated by the erasing light. Optionally, in other embodiments, the color of the color-developing area 141 is allowed to gradually fade before being irradiated by the erasing light 163 to reduce the performance requirements of the photochromic layer 140.

[0052] It should be understood that the primary color area refers to the area on the photochromic layer 140 where the color is not changed by written light, and the color of the primary color area can be colorless, transparent or other colors.

[0053] The photochromic layer 140 may include a photochromic material. The photochromic material generally corresponds to two specific wavelengths / colors of light that can change its color. Specifically, the photochromic material can change color under the irradiation of the first specific wavelength of light, from the current first color to the second color. The photochromic material can change color under the irradiation of the second specific wavelength of light, from the second color back to the first color. The first specific wavelength of light and the second specific wavelength of light can be used as writing light and erasing light, respectively. By controlling the wavelength / color of light emitted by the first light-emitting unit, the first light-emitting unit can emit writing light, and by controlling the wavelength / color of light emitted by the second light-emitting unit or the third light-emitting unit below, the second light-emitting unit or the third light-emitting unit can emit erasing light. Exemplarily, the photochromic layer may include a photochromic material whose corresponding first specific wavelength of light is blue light and whose corresponding second specific wavelength of light is green light, and the photochromic material changes from colorless and transparent to purple under the irradiation of blue light, and the photochromic material that has changed to purple can change from purple to colorless and transparent under the irradiation of green light.

[0054] In addition, the photochromic material in the photochromic layer 140 can be an organic polymer or small molecule material, such as diarylethene (DAE), etc., or an inorganic material, which can form a fully solid film for making the photochromic layer 140. In an optional embodiment, the writing light emitted by the first light emitting unit 150 can be blue light, and the photochromic layer 140 can change from colorless and transparent to purple under the irradiation of blue light, forming a purple color development area, and the corresponding erasing light is green light, and the color of the purple color development area can change from purple to colorless and transparent under the irradiation of green light. By selecting a suitable photochromic material, the color of the color development area on the photochromic layer 140 can remain unchanged before being irradiated by the erasing light. The color development area can display color by passively reflecting ambient light, and can also maintain a good display effect under the condition of strong ambient light.

[0055] It should be noted that the predetermined time can be set according to the time required for the photochromic layer 140 to absorb the writing light and change color. When the time for the first light-emitting unit 150 to emit the writing light reaches the predetermined time, the first light-emitting unit 150 is extinguished, thereby saving electricity as much as possible and reducing the power consumption of the display panel 100.

[0056] As a feasible implementation, part / all of the plurality of first light-emitting units 150 may be controlled to emit writing light according to a predetermined pattern, so that the color development area formed on the photochromic layer 140 forms the predetermined pattern. For example, the first light-emitting units 150 required when the first light-emitting units 150 are used to form the predetermined pattern may be determined according to the predetermined pattern, and the required first light-emitting units 150 may be controlled to emit writing light toward the photochromic layer 140, so that the corresponding pattern formed on the photochromic layer 140 is the display area of ​​the predetermined pattern. As long as the erasing light is not emitted to the display area, the display area can continue to exist, thereby continuously displaying the predetermined pattern.

[0057] In the embodiment of the present application, the display panel 100 includes a base substrate 110, a pixel light-emitting layer 120, an encapsulation layer 130 and a photochromic layer 140. The pixel light-emitting layer 120 is disposed on the base substrate 110, the photochromic layer 140 is disposed on the side of the pixel light-emitting layer 120 away from the base substrate 110, and the encapsulation layer 130 is disposed between the pixel light-emitting layer 120 and the photochromic layer 140. A plurality of first light-emitting units 150 are disposed in the pixel light-emitting layer 120, and the first light-emitting units 150 are connected to the first driving circuit 111 on the base substrate 110; the first driving circuit 111 is used to drive the first light-emitting unit 150 to emit writing light. The area on the photochromic layer 140 irradiated by the writing light changes color to form a color development area, and the color of the color development area is different from the color of the primary color area on the photochromic layer 140 that is not irradiated by the writing light, wherein the color of the color development area changes to the same color as the primary color area after being irradiated by the erasing light, and the color of the color development area remains unchanged before being irradiated by the erasing light. By controlling the first light-emitting units 150 to emit writing light, a color development area corresponding to a predetermined pattern composed of the first light-emitting units 150 can be formed on the photochromic layer 140, thereby realizing the display of the predetermined pattern. After the display area of ​​the predetermined pattern is formed on the photochromic layer 140, the first light-emitting unit 150 can be extinguished, and the predetermined pattern can be displayed only by reflecting the ambient light through the display area without consuming electric energy, which can significantly reduce the power consumption of the display panel 100. In particular, in the scene where the predetermined pattern needs to be displayed continuously, the predetermined pattern can be displayed by using the continuously existing display area to greatly save electric energy, so that the average power consumption of the display panel 100 can even be reduced to near zero.

[0058] In order to reduce the power consumption of the display device, some display devices use electronic paper to make the display panel 100. Although electronic paper can reduce the power consumption of the display device to a certain extent, due to the mechanism problems of the electronic ink material and control method of the electronic paper, it has problems such as slow refresh rate and poor reliability.

[0059] like Figure 1-3 or Figure 5-7As shown, in some optional embodiments, the display panel 100 further includes a second light emitting unit 160 for emitting erasing light, and the second light emitting unit 160 is disposed on a side of the photochromic layer 140 close to the base substrate 110 .

[0060] The second light-emitting unit 160 can emit an erasing light, so that the color of the color-developing area on the photochromic layer 140 changes to the same color as the original color area under the irradiation of the erasing light, so that the pattern displayed by the color-developing area on the photochromic layer 140 can be eliminated, so as to prepare for the next pattern writing. Since the response time of the photochromic material to the writing light and the erasing light can reach the millisecond level, the photochromic layer 140 can quickly refresh and display the pattern under the action of the writing light and the erasing light. In addition, in the embodiment of the present application, the first light-emitting unit 150, the second light-emitting unit 160, and the photochromic layer 140 can all be made of stable solid materials, which have good reliability and can solve the shortcomings of easy leakage and poor reliability of liquid electronic ink in electronic paper.

[0061] like Figure 1-3 As shown, in some optional embodiments, the display panel 100 includes a plurality of second light-emitting units 160 , and the plurality of second light-emitting units 160 are located in the pixel light-emitting layer 120 ; and the orthographic projection of each first light-emitting unit 150 on the photochromic layer 140 is adjacent to the orthographic projection of at least one second light-emitting unit 160 on the photochromic layer 140 .

[0062] For example, the first light-emitting unit 150 may correspond to the second light-emitting unit 160 one by one, and the orthographic projection of each first light-emitting unit 150 on the photochromic layer 140 is adjacent to the orthographic projection of the second light-emitting unit 160 corresponding to the first light-emitting unit 150 on the photochromic layer 140. Alternatively, for each first light-emitting unit 150, a plurality of second light-emitting units 160 may be arranged around the first light-emitting unit 150, and the orthographic projection of each first light-emitting unit 150 on the photochromic layer 140 is adjacent to the orthographic projection of the plurality of second light-emitting units 160 corresponding to the first light-emitting unit 150 on the photochromic layer 140.

[0063] Similar to the first light-emitting unit 150, the second light-emitting unit 160 may include a second anode layer 161, a second hole injection layer, a second hole transport layer, a second light-emitting layer, a second electron transport layer, a second electron injection layer, a second cathode layer, etc., which are arranged in sequence and will not be described in detail here. Figure 1-3 As shown, the second anode layer 161 is connected to the second driving circuit 112 on the base substrate 110, so that the second light emitting unit 160 can be driven by the second driving circuit 112 to emit erasing light. Figure 1-3As shown, the second light emitting unit 160 can share the same cathode layer with the first light emitting unit 150, that is, the first cathode layer 157 is also used as the second cathode layer to simplify the circuit structure. The second driving circuit 112 on the substrate 110 applies a driving signal to the second anode layer 161 of the second light emitting unit 160, so that the second light emitting layer between the second anode layer 161 and the second cathode layer of the second light emitting unit 160 can emit an erasing light. Figure 3 As shown, after the second light emitting layer 162 emits the erasing light 163 to irradiate the photochromic layer 140 , the color of the color development area irradiated by the erasing light 163 can be changed to the same as the primary color area.

[0064] In the embodiment of the present application, the display panel 100 includes a plurality of second light emitting units 160, and the plurality of second light emitting units 160 are located in the pixel light emitting layer 120; and the orthographic projection of each first light emitting unit 150 on the photochromic layer 140 is adjacent to the orthographic projection of at least one second light emitting unit 160 on the photochromic layer 140. For a color development area formed based on the writing light emitted by a certain first light emitting unit 150, since the orthographic projection of the first light emitting unit 150 on the photochromic layer 140 is adjacent to the orthographic projection of at least one second light emitting unit 160 on the photochromic layer 140, the color of the color development area can be changed to the same as the primary color area by emitting an erasing light through at least one second light emitting unit 160, so that the color of any display area can be erased in a targeted manner, and the color development area can be restored to the primary color area, so that the control of the display area on the photochromic layer 140 is more flexible.

[0065] In some optional embodiments, the second light-emitting unit 160 is arranged on the side of the first light-emitting unit 150 away from the base substrate, and at least a portion of the orthographic projection of the second light-emitting unit 160 on the photochromic layer 140 intersects with the orthographic projection of the first light-emitting unit 150 on the photochromic layer 140, so that when the second light-emitting unit 160 emits erasing light 163 to the photochromic layer 140, at least a portion of the erasing light 163 can be concentrated on the color development area to improve the efficiency of eliminating the color development area.

[0066] In some optional embodiments, along the thickness direction of the display panel 100 , the second light emitting unit 160 is adjacent to the first light emitting unit 150 , and the orthographic projection of the second light emitting unit 160 on the photochromic layer 140 coincides with the orthographic projection of the first light emitting unit 150 on the photochromic layer 140 .

[0067] As a feasible implementation, similar to the first light-emitting unit 150, the second light-emitting unit 160 may include a second anode layer, a second hole injection layer, a second hole transport layer, a second light-emitting layer, a second electron transport layer, a second electron injection layer, a second cathode layer, etc., which are arranged in sequence. A second driving circuit corresponding to the second light-emitting unit 160 may be provided on the base substrate 110, and a via hole may be provided in the first light-emitting unit 150. The second anode layer of each second light-emitting unit 160 may be connected to a second driving circuit through a via hole provided in the first light-emitting unit 150, so as to drive the second light-emitting unit 160 to emit erasing light through the second driving circuit.

[0068] As another feasible implementation, the second light-emitting unit 160 may include a second light-emitting layer, and the second light-emitting layer is located between the first light-emitting layer and the first electron transport layer in the first light-emitting unit 150, that is, the second light-emitting unit 160 and the first light-emitting unit 150 share the first anode layer 151, the first hole injection layer 152, the first hole transport layer 153, the first electron transport layer 155, the first electron injection layer 156 and the first cathode layer 157, etc. The light-emitting voltage or light-emitting current of the first light-emitting unit 150 and the second light-emitting unit 160 may be set to be different, and by controlling the voltage or current between the first anode layer 151 and the first cathode layer 157, one of the first light-emitting layer and the second light-emitting layer may be controlled to emit light, that is, one of the first light-emitting unit 150 and the second light-emitting unit 160 may be controlled to emit light.

[0069] In the embodiment of the present application, the second light-emitting unit 160 is arranged adjacent to the first light-emitting unit 150 along the thickness direction of the display panel 100, and the orthographic projection of the second light-emitting unit 160 on the photochromic layer 140 coincides with the orthographic projection of the first light-emitting unit 150 on the photochromic layer 140, so that the trajectory of the erasing light 163 irradiated by the second light-emitting unit 160 to the photochromic layer 140 can be close to the trajectory of the writing light 158 ​​irradiated by the first light-emitting unit 150 to the photochromic layer 140, so that the erasing light 163 can be irradiated to the color development area more accurately, avoiding the waste of the erasing light 163.

[0070] It should be noted that the second light emitting unit 160 can be made of a transparent or translucent material, such as indium oxide, so that the writing light 158 ​​emitted by the first light emitting unit 150 can pass through the second light emitting unit 160 to irradiate the photochromic layer 140. The specific structural composition of the second light emitting unit 160 can be similar to that of the first light emitting unit 150, and will not be repeated here.

[0071] like Figure 5-7As shown, in some optional embodiments, the second light-emitting unit 160 is disposed between the pixel light-emitting layer 120 and the photochromic layer 140; and, the encapsulation layer 130 includes a first encapsulation layer 131 and a second encapsulation layer 132, the first encapsulation layer 131 is disposed between the pixel light-emitting layer 120 and the second light-emitting unit 160, and the second encapsulation layer 132 is disposed between the second light-emitting unit 160 and the photochromic layer 140.

[0072] For example, Figure 6 As shown, the writing light 158 ​​emitted by the first light emitting unit 150 can pass through the second light emitting unit 160 to irradiate the photochromic layer 140, so that a color development area 141 is formed on the photochromic layer 140. Figure 7 As shown, the erasing light 163 emitted by the second light emitting unit 160 can pass through and illuminate the photochromic layer 140 , so that the color of the color development area 141 on the photochromic layer 140 changes to the same as the primary color area.

[0073] The first encapsulation layer 131 and the second encapsulation layer 132 may be transparent CVD (chemical vapor deposition) encapsulation layers, i.e., encapsulation layers formed by CVD process, and the materials thereof may be transparent insulating materials. The light-emitting layer and other structures in the second light-emitting unit 160 may be made of transparent materials, so that the writing light emitted by the first light-emitting unit 150 may pass through the second light-emitting unit 160 to irradiate the photochromic layer 140.

[0074] The second light-emitting unit 160 is disposed between the pixel light-emitting layer 120 and the photochromic layer 140, so that the space between the pixel light-emitting layer 120 and the photochromic layer 140 can be fully utilized. In addition, the first encapsulation layer 131 is disposed between the pixel light-emitting layer 120 and the second light-emitting unit 160, and the second encapsulation layer 132 is disposed between the second light-emitting unit 160 and the photochromic layer 140, so that a certain distance can be provided between the second light-emitting unit 160 and the pixel light-emitting layer 120 and the photochromic layer 140, thereby reducing the restrictions of the pixel light-emitting layer 120 and the photochromic layer 140 on the installation of the second light-emitting unit 160, and facilitating the installation of the second light-emitting unit 160.

[0075] like Figure 5-Figure 7 As shown, in some optional embodiments, the orthographic projection of the first light-emitting unit 150 on the photochromic layer 140 is located within the orthographic projection of the second light-emitting unit 160 on the photochromic layer 140 .

[0076] After the first light emitting unit 150 emits writing light to form a color development area on the photochromic layer 140, the second light emitting unit 160 may emit erasing light. By setting the orthographic projection of the first light emitting unit 150 on the photochromic layer 140 to be within the orthographic projection of the second light emitting unit 160 on the photochromic layer 140, the second light emitting unit 160 may have a larger projection range on the photochromic layer 140 than the first light emitting unit 150, so that the range of irradiation of the erasing light emitted by the second light emitting unit 160 on the photochromic layer 140 covers the above-mentioned color development area, so as to ensure that the color of the color development area at any position on the photochromic layer 140 can be changed to the same color as the original color area by the erasing light of the second light emitting unit 160, so as to avoid the color of the color development area remaining when the color of the color development area is erased by changing the light.

[0077] In some optional embodiments, the encapsulation layer 130 further includes a first inkjet-printed encapsulation layer 134; Figure 8 As shown, the first inkjet printed encapsulation layer 134 is located between the first encapsulation layer 131 and the second light emitting unit 160; or Fig. 9 As shown, the first inkjet-printed encapsulation layer 134 is located between the second light-emitting unit 160 and the second encapsulation layer 132 .

[0078] It should be understood that the inkjet-printed encapsulation layer 130 is an encapsulation layer made by inkjet printing, and the first inkjet-printed encapsulation layer 134 and the second inkjet-printed encapsulation layer 135 thereunder can be made of transparent materials to avoid shielding the writing light or the erasing light.

[0079] By arranging the first inkjet-printed encapsulation layer 134 between the first encapsulation layer 131 and the second light-emitting unit 160, or arranging the first inkjet-printed encapsulation layer 134 between the second light-emitting unit 160 and the second encapsulation layer 132, leveling can be performed on the side of the second light-emitting unit 160 close to the first encapsulation layer 131, or leveling can be performed on the side of the second light-emitting unit 160 close to the second encapsulation layer 132, which can avoid the arrangement of the second light-emitting unit 160 affecting the flatness of the second encapsulation layer 132 and the photochromic layer 140, and is conducive to making the arrangement of the second encapsulation layer 132 and the photochromic layer 140 more flat.

[0080] In some optional embodiments, the encapsulation layer 130 further includes a second inkjet printing encapsulation layer 135 and a third encapsulation layer 133. The third encapsulation layer 133 and the second encapsulation layer 132 may be transparent CVD encapsulation layers. Fig.10As shown, when the first inkjet-printed encapsulation layer 134 is located between the first encapsulation layer 131 and the second light-emitting unit 160, the second inkjet-printed encapsulation layer 135 is arranged on the side of the second encapsulation layer 132 close to the photochromic layer 140, and the third encapsulation layer 133 is arranged between the second inkjet-printed encapsulation layer 135 and the photochromic layer 140.

[0081] In the embodiment of the present application, the second inkjet-printed encapsulation layer 135 can be used for leveling again, and the third encapsulation layer 133 can form a transition between the second inkjet-printed encapsulation layer 135 and the photochromic layer 140 , thereby better ensuring the flatness of the photochromic layer 140 .

[0082] It should be understood that the above-mentioned encapsulation layer 130 includes the first encapsulation layer 131, the second encapsulation layer 132, the third encapsulation layer 133, the first inkjet-printed encapsulation layer 134, the first inkjet-printed encapsulation layer 134, etc., which are all made of transparent materials to allow writing light or erasing light to pass through the encapsulation layer 130 to irradiate the photochromic layer 140.

[0083] In some optional embodiments, the display panel 100 further includes a third light emitting unit; the third light emitting unit is used to emit an erasing light toward the photochromic layer 140 at a side of the photochromic layer 140 away from the base substrate 110. The specific introduction of the erasing light can be referred to the embodiment of the second light emitting unit 160 above, which will not be repeated here.

[0084] like Fig.11 As shown, the third light emitting unit is not located on the side of the photochromic layer 140 close to the base substrate 110. Fig.12 As shown, the writing light 158 ​​emitted by the first light emitting unit 150 can be irradiated to the photochromic layer 140 after passing through the encapsulation layer 130, so that the color development area 141 is formed on the photochromic layer 140. The third light emitting unit can emit an erasing light 163 toward the photochromic layer 140 on the side of the photochromic layer 140 away from the substrate 110, so that the color of the color development area 141 on the photochromic layer 140 changes to the same as the primary color area. The erasing light 163 emitted by the third light emitting unit can refer to Fig.13 shown.

[0085] Similar to the first light-emitting unit 150, the third light-emitting unit may include a third anode layer, a third hole injection layer, a third hole transport layer, a third light-emitting layer, a third electron transport layer, a third electron injection layer, a third cathode layer, etc. arranged in sequence, which will not be repeated here.

[0086] Optionally, the third light-emitting unit may be a movable light-emitting unit. When it is necessary to emit erasing light to the color-developing area on the photochromic layer 140, the third light-emitting unit may be moved to the side of the photochromic layer away from the base substrate 110, so that the third light-emitting unit emits erasing light toward the photochromic layer 140. When it is not necessary to emit erasing light to the color-developing area on the photochromic layer 140, the third light-emitting unit may be moved away to avoid the third light-emitting unit obstructing the user from viewing the display panel 100. Of course, the third light-emitting unit may also be a light-emitting unit fixed to the side of the photochromic layer 140 away from the base substrate 110, and the embodiment of the present application does not limit the specific arrangement of the third light-emitting unit.

[0087] In the embodiment of the present application, the display panel 100 also includes a third light-emitting unit; the third light-emitting unit is used to emit erasing light toward the photochromic layer 140 on the side of the photochromic layer 140 away from the base substrate 110. The third light-emitting unit can be set to be movable, or the third light-emitting unit can be set to be fixed on the side of the photochromic layer 140 away from the base substrate 110, so that the setting of the third light-emitting unit does not interfere with the setting of the base substrate 110, the pixel light-emitting layer 120, the encapsulation layer 130 and the first light-emitting unit 150, so that the setting of the light-emitting unit for emitting erasing light is more flexible.

[0088] In some optional embodiments, the photochromic layer 140 may include a plurality of sub-chromic layers stacked along the thickness direction of the display panel 100, and the color development area on the photochromic layer 140 includes a sub-color development area on the sub-chromic layer, and the color development area may be composed of a sub-chromic layer or a combination of sub-color development areas of multiple sub-chromic layers.

[0089] The first light-emitting unit 150 may include a plurality of first sub-light-emitting units, and the first sub-light-emitting units correspond to the sub-color-changing layers one by one. The first sub-light-emitting units are used to emit writing light, and the wavelengths of the writing light emitted by each first sub-light-emitting unit are different; the area on the sub-color-changing layer irradiated by the writing light of the corresponding first sub-light-emitting unit changes color to form a sub-color-developing area, and the colors of the sub-color-developing areas formed on each sub-color-changing layer are different.

[0090] As a feasible implementation, each sub-color-changing layer changes color to form a sub-color display area only under the irradiation of the writing light of the corresponding first sub-light-emitting unit, and does not change color under the irradiation of the writing light of other first sub-light-emitting units. Specifically, each sub-color-changing layer can use different photochromic materials, and the wavelength of the writing light required for the color change of the photochromic materials used in each sub-color-changing layer is different.

[0091] By using a combination of sub-color development areas with different sub-color changing layers in the color development area, the color development area can display different colors, so that a colorful pattern can be presented on the display panel 100.

[0092] Optionally, the sub-color-developing areas of each sub-color-changing layer can be set to change color to the same color as the sub-color-changing area within the primary color area under the irradiation of erasing light of different wavelengths. At this time, each of the above-mentioned second light-emitting units 160 or third light-emitting units may include multiple second sub-light-emitting units, and the second sub-light-emitting units correspond to the sub-color-changing layers one by one. The second sub-light-emitting unit is used to emit erasing light, and the wavelength of the erasing light emitted by each second sub-light-emitting unit is different; after the sub-color-developing area on the sub-color-changing layer is irradiated by the erasing light of the corresponding second sub-light-emitting unit, the color of the sub-color-developing area changes to the same color as the sub-color-developing area within the primary color area, and after the sub-color-developing areas on other sub-color-changing layers are irradiated by the erasing light of the second sub-light-emitting unit, the color of the sub-color-developing areas on other sub-color-changing layers remains unchanged. Therefore, it is possible to select the corresponding second sub-light-emitting unit to emit erasing light for the sub-color-developing area on a certain sub-color-changing layer, so that the color of the sub-color-developing area changes to the same color as the sub-color-developing area within the primary color area, without interfering with the color retention of the sub-color-developing areas on other sub-color-changing layers. Alternatively, the sub-color-changing areas of each sub-color-changing layer may be set to change color to the same color as the sub-color-changing area within the primary color area under the irradiation of erasing light of the same wavelength. At this time, each of the above-mentioned second light-emitting units 160 may include a second sub-light-emitting unit, and after the sub-color-changing areas on each sub-color-changing layer are irradiated with the erasing light of the second sub-light-emitting unit, their colors change to the same color as the sub-color-changing area within the primary color area.

[0093] In the embodiment of the present application, the photochromic layer 140 includes a plurality of sub-chromic layers, and the first light-emitting unit 150 includes a plurality of first sub-light-emitting units, and the first sub-light-emitting units correspond to the sub-chromic layers one by one. The first sub-light-emitting units are used to emit writing light, and the wavelengths of the writing light emitted by each first sub-light-emitting unit are different. The area on the sub-chromic layer irradiated by the writing light of the corresponding first sub-light-emitting unit undergoes a color change to form a sub-coloring area, and the color of the sub-coloring area formed on each sub-chromic layer is different. Thus, each first sub-light-emitting unit in different first sub-light-emitting units can be used to control the formation of a sub-coloring area on the corresponding sub-chromic layer, and by adjusting the sub-coloring area included in the coloring area, the color of the coloring area can be adjusted so that the coloring area presents a variety of colors, thereby enabling the display panel 100 to display a colorful pattern, which can effectively improve the display effect of the display panel 100 and broaden the applicable scenarios of the display panel 100.

[0094] like Fig.14 As shown, according to a second aspect of an embodiment of the present application, a method for preparing a display panel is provided, the method comprising:

[0095] S210, forming a pixel light emitting layer on one side of the base substrate.

[0096] S220, forming an encapsulation layer on a side of the pixel light emitting layer facing away from the base substrate.

[0097] S230 , forming a photochromic layer on a side of the encapsulation layer away from the pixel light-emitting layer.

[0098] Among them, a plurality of first light-emitting units are arranged in the pixel light-emitting layer, and the first light-emitting units are connected to the first driving circuit on the substrate; the first driving circuit is used to drive the first light-emitting unit to emit writing light; the area on the photochromic layer irradiated by the writing light changes color to form a color-developing area and maintains it, the color of the color-developing area is different from the color of the primary color area on the photochromic layer that is not irradiated by the writing light, the color of the color-developing area changes to the same color as the primary color area after being irradiated by the erasing light, and the color of the color-developing area remains unchanged before being irradiated by the erasing light.

[0099] In some optional embodiments, a second light emitting unit is formed on a side of the base substrate where the pixel light emitting layer is disposed.

[0100] In some optional embodiments, forming a second light-emitting unit on a side of the base substrate where the pixel light-emitting layer is provided includes: forming a plurality of the second light-emitting units on the pixel light-emitting layer; wherein the orthographic projection of each of the first light-emitting units on the photochromic layer is adjacent to the orthographic projection of at least one of the second light-emitting units on the photochromic layer.

[0101] In some optional embodiments, forming the second light-emitting unit on the side of the base substrate where the pixel light-emitting layer is provided comprises: forming the second light-emitting unit on the side of the first light-emitting unit away from the base substrate; wherein at least a portion of the orthographic projection of the second light-emitting unit on the photochromic layer intersects with the orthographic projection of the first light-emitting unit on the photochromic layer;

[0102] In some optional embodiments, along the thickness direction of the display panel, the second light-emitting unit is adjacent to the first light-emitting unit, and the orthographic projection of the second light-emitting unit on the photochromic layer coincides with the orthographic projection of the first light-emitting unit on the photochromic layer.

[0103] In some optional embodiments, forming an encapsulation layer on a side of the pixel light-emitting layer away from the substrate substrate includes: forming a first encapsulation layer on a side of the pixel light-emitting layer away from the substrate substrate; forming the second light-emitting unit on a side of the first light-emitting unit away from the substrate substrate includes: forming the second light-emitting unit on a side of the first encapsulation layer away from the pixel light-emitting layer; forming an encapsulation layer on a side of the pixel light-emitting layer away from the substrate substrate also includes: forming a second encapsulation layer on a side of the second light-emitting unit away from the first encapsulation layer;

[0104] In some optional embodiments, the orthographic projection of the first light-emitting unit on the photochromic layer is located within the orthographic projection of the second light-emitting unit on the photochromic layer;

[0105] In some optional embodiments, forming the encapsulation layer on the side of the pixel light-emitting layer away from the base substrate further comprises: forming a first inkjet-printed encapsulation layer on the side of the first encapsulation layer away from the pixel light-emitting layer, so that the first inkjet-printed encapsulation layer is located between the first encapsulation layer and the second light-emitting unit, or forming a first inkjet-printed encapsulation layer on the side of the second light-emitting unit away from the first encapsulation layer, so that the first inkjet-printed encapsulation layer is located between the second light-emitting unit and the second encapsulation layer;

[0106] In some optional embodiments, forming an encapsulation layer on a side of the pixel light-emitting layer facing away from the substrate further includes: forming a first inkjet-printed encapsulation layer on a side of the first encapsulation layer facing away from the pixel light-emitting layer, forming a second inkjet-printed encapsulation layer on a side of the second encapsulation layer facing away from the second light-emitting unit, and forming a third encapsulation layer on a side of the second inkjet-printed encapsulation layer facing away from the second encapsulation layer, so that the third encapsulation layer is located between the second inkjet-printed encapsulation layer and the photochromic layer.

[0107] The method for preparing the display panel provided in the embodiment of the present application is based on the same inventive concept as the embodiment of the aforementioned display panel 100 and can achieve the same effect. The specific implementation process can refer to the description in the embodiment of the aforementioned display panel 100 and will not be repeated here.

[0108] According to a third aspect of the embodiments of the present application, a display device is provided, comprising a display panel 100 as described in any of the above embodiments. The display device may be a display, a mobile phone, a television, or a tablet computer.

[0109] The display device provided in the embodiment of the present application and the embodiment of the aforementioned display panel 100 are based on the same inventive concept and can achieve the same effect. The specific implementation process can refer to the description in the embodiment of the aforementioned display panel 100 and will not be repeated here.

[0110] It should be pointed out that, according to the needs of implementation, the various components / steps described in the embodiments of the present application can be split into more components / steps, or two or more components / steps or partial operations of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of the present application.

[0111] The above-mentioned method according to the embodiment of the present application can be implemented in hardware, firmware, or implemented as software or computer code that can be stored in a recording medium (such as a CD-ROM, RAM, floppy disk, hard disk or magneto-optical disk), or implemented as a computer code originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded through a network and to be stored in a local recording medium, so that the method described herein can be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor or programmable or dedicated hardware (such as an Application Specific Integrated Circuit (ASIC) or a Field Programmable Gate Array (FPGA)). It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component (for example, a random access memory (RAM), a read-only memory (ROM), a flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by a computer, a processor or hardware, the method described herein is implemented. In addition, when a general purpose computer accesses code for implementing the methods shown herein, the execution of the code transforms the general purpose computer into a special purpose computer for executing the methods shown herein.

[0112] Those of ordinary skill in the art will appreciate that the units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of the present application.

[0113] The above implementation methods are only used to illustrate the embodiments of the present application, and are not limitations on the embodiments of the present application. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application. The scope of patent protection of the embodiments of the present application should be limited by the claims.

Claims

1. A display panel, characterized in that: include: Substrate substrate, pixel light emitting layer, encapsulation layer and photochromic layer; The pixel light-emitting layer is arranged on the base substrate, the photochromic layer is arranged on a side of the pixel light-emitting layer away from the base substrate, and the encapsulation layer is arranged between the pixel light-emitting layer and the photochromic layer; A plurality of first light-emitting units are arranged in the pixel light-emitting layer, and the first light-emitting units are connected to a first driving circuit on the base substrate; the first driving circuit is used to drive the first light-emitting units to emit writing light; The area on the photochromic layer irradiated by the writing light changes color to form a color development area and maintains the color of the color development area, and the color of the color development area is different from the color of the primary color area on the photochromic layer that is not irradiated by the writing light, wherein the color of the color development area changes to the same color as the primary color area after being irradiated by the erasing light, and the color of the color development area remains unchanged before being irradiated by the erasing light.

2. The display panel according to claim 1, characterized in that: The display panel further includes a second light emitting unit for emitting erasing light, and the second light emitting unit is disposed on a side of the photochromic layer close to the base substrate.

3. The display panel according to claim 2, characterized in that: The display panel includes a plurality of the second light emitting units, and the plurality of the second light emitting units are located in the pixel light emitting layer; and The orthographic projection of each of the first light-emitting units on the photochromic layer is adjacent to the orthographic projection of at least one of the second light-emitting units on the photochromic layer.

4. The display panel according to claim 2, characterized in that: The second light emitting unit is disposed on a side of the first light emitting unit away from the base substrate, and at least a portion of an orthographic projection of the second light emitting unit on the photochromic layer intersects with an orthographic projection of the first light emitting unit on the photochromic layer; Preferably, along the thickness direction of the display panel, the second light emitting unit is spaced apart from the first light emitting unit, and the orthographic projection of the first light emitting unit on the photochromic layer is located within the orthographic projection of the second light emitting unit on the photochromic layer.

5. The display panel according to claim 4, characterized in that: The second light emitting unit is disposed between the pixel light emitting layer and the photochromic layer; and, The encapsulation layer comprises a first encapsulation layer and a second encapsulation layer, the first encapsulation layer is arranged between the pixel light-emitting layer and the second light-emitting unit, and the second encapsulation layer is arranged between the second light-emitting unit and the photochromic layer; Preferably, the encapsulation layer further comprises a first inkjet-printed encapsulation layer; the first inkjet-printed encapsulation layer is located between the first encapsulation layer and the second light-emitting unit, or the first inkjet-printed encapsulation layer is located between the second light-emitting unit and the second encapsulation layer; Preferably, the encapsulation layer further includes a second inkjet-printed encapsulation layer and a third encapsulation layer; when the first inkjet-printed encapsulation layer is located between the first encapsulation layer and the second light-emitting unit, the second inkjet-printed encapsulation layer is arranged on a side of the second encapsulation layer close to the photochromic layer, and the third encapsulation layer is arranged between the second inkjet-printed encapsulation layer and the photochromic layer.

6. The display panel according to claim 2, characterized in that: The second light emitting unit is arranged on a side of the first light emitting unit away from the base substrate, the second light emitting unit is adjacent to the first light emitting unit, and the orthographic projection of the second light emitting unit on the photochromic layer coincides with the orthographic projection of the first light emitting unit on the photochromic layer.

7. The display panel according to claim 1, characterized in that: The display panel further comprises a third light emitting unit; the third light emitting unit is used to emit the erasing light toward the photochromic layer at a side of the photochromic layer away from the base substrate; Preferably, the photochromic layer includes a plurality of sub-chromic layers stacked along the thickness direction of the display panel, the color development area on the photochromic layer includes a sub-color development area on the sub-chromic layer; the first light-emitting unit includes a plurality of first sub-light-emitting units, and the first sub-light-emitting units correspond to the sub-chromic layers one by one; The first sub-light-emitting unit is used to emit the writing light, and the wavelength of the writing light emitted by each of the first sub-light-emitting units is different; the area on the sub-color-changing layer that is irradiated by the writing light of the corresponding first sub-light-emitting unit undergoes a color change to form the sub-color-developing area, and the color of the sub-color-developing area formed on each of the sub-color-changing layers is different.

8. A method for preparing a display panel, characterized in that: The method comprises: forming a pixel light emitting layer on one side of the base substrate; Forming an encapsulation layer on a side of the pixel light emitting layer away from the base substrate; forming a photochromic layer on a side of the encapsulation layer away from the pixel light-emitting layer; Among them, a plurality of first light-emitting units are arranged in the pixel light-emitting layer, and the first light-emitting units are connected to the first driving circuit on the base substrate; the first driving circuit is used to drive the first light-emitting unit to emit writing light; the area on the photochromic layer irradiated by the writing light changes color to form a color development area and maintains it, the color of the color development area is different from the color of the primary color area on the photochromic layer that is not irradiated by the writing light, the color of the color development area changes to the same color as the primary color area after being irradiated by the erasing light, and the color of the color development area remains unchanged before being irradiated by the erasing light.

9. The method according to claim 8, characterized in that The method further comprises: forming a second light emitting unit on a side of the base substrate where the pixel light emitting layer is disposed; Preferably, forming a second light-emitting unit on a side of the base substrate where the pixel light-emitting layer is provided comprises: forming a plurality of the second light-emitting units on the pixel light-emitting layer; wherein the orthographic projection of each of the first light-emitting units on the photochromic layer is adjacent to the orthographic projection of at least one of the second light-emitting units on the photochromic layer; Preferably, forming the second light-emitting unit on the side of the substrate where the pixel light-emitting layer is arranged comprises: forming the second light-emitting unit on the side of the first light-emitting unit away from the substrate; wherein at least a part of the orthographic projection of the second light-emitting unit on the photochromic layer intersects with the orthographic projection of the first light-emitting unit on the photochromic layer; Preferably, forming an encapsulation layer on a side of the pixel light emitting layer away from the base substrate comprises: forming a first encapsulation layer on a side of the pixel light emitting layer away from the base substrate; The forming of the second light-emitting unit on a side of the first light-emitting unit away from the base substrate comprises: forming the second light-emitting unit on a side of the first encapsulation layer away from the pixel light-emitting layer; The forming of the encapsulation layer on the side of the pixel light emitting layer away from the base substrate further comprises: forming a second encapsulation layer on the side of the second light emitting unit away from the first encapsulation layer; Preferably, the orthographic projection of the first light-emitting unit on the photochromic layer is located within the orthographic projection of the second light-emitting unit on the photochromic layer; Preferably, forming the encapsulation layer on the side of the pixel light-emitting layer away from the base substrate further comprises: forming a first inkjet-printed encapsulation layer on the side of the first encapsulation layer away from the pixel light-emitting layer, so that the first inkjet-printed encapsulation layer is located between the first encapsulation layer and the second light-emitting unit, or forming a first inkjet-printed encapsulation layer on the side of the second light-emitting unit away from the first encapsulation layer, so that the first inkjet-printed encapsulation layer is located between the second light-emitting unit and the second encapsulation layer; Preferably, forming an encapsulation layer on a side of the pixel light-emitting layer away from the base substrate further comprises: forming a first inkjet-printed encapsulation layer on a side of the first encapsulation layer away from the pixel light-emitting layer, forming a second inkjet-printed encapsulation layer on a side of the second encapsulation layer away from the second light-emitting unit, and forming a third encapsulation layer on a side of the second inkjet-printed encapsulation layer away from the second encapsulation layer, so that the third encapsulation layer is located between the second inkjet-printed encapsulation layer and the photochromic layer.

10. A display device, characterized in that: The invention comprises a display panel as claimed in any one of claims 1 to 7.

Images