CN113437241B - Display substrate, display device and preparation method of display substrate - Google Patents

Abstract

The disclosure provides a display substrate, a display device and a preparation method of the display substrate, and belongs to the technical field of display. The display substrate disclosed by the invention is provided with pixel areas which are arranged in an array manner and a non-display area surrounding the pixel areas; the display substrate includes: a substrate base; a plurality of light emitting units arranged on the substrate, wherein one light emitting unit is arranged in one pixel area, and each light emitting unit comprises a light emitting device; the color filter layer is arranged on one side of the plurality of light-emitting units, which is away from the substrate; the color filter layer comprises a plurality of color resistance units and a black matrix arranged among the color resistance units; a color resistance unit is arranged in one pixel area; the black matrix is arranged in the non-display area; at least one light hole is arranged on the black matrix, and the light hole can transmit light emitted by one light emitting device.

Description

Display substrate, display device and preparation method of display substrate

Technical Field

The disclosure belongs to the technical field of display, and particularly relates to a display substrate, a display device and a preparation method of the display substrate.

Background

Organic Light-EMITTING DEVICE (OLED) has many advantages of self-luminescence, fast response, high brightness, light and thin, etc. compared with the liquid crystal display device, and is considered as the next generation mainstream display technology, especially the flexible and flexible characteristics, so that the OLED display device becomes the first choice for flexible display.

The color filter layer in the conventional OLED display device includes a black matrix structure (BM) which can absorb external light to reduce the reflectivity of the screen, however, due to the strong light absorption performance of the BM material, the problems of too fast luminance attenuation (L-Decay) and too large color shift (color shift) of the OLED display device at a large viewing angle may occur.

Disclosure of Invention

The disclosure aims to at least solve one of the technical problems in the prior art, and provides a display substrate, a display device and a preparation method of the display substrate.

In a first aspect, an embodiment of the present disclosure provides a display substrate having pixel regions arranged in an array, and a non-display region surrounding the pixel regions; the display substrate includes:

A substrate base;

A plurality of light emitting units arranged on the substrate, wherein one light emitting unit is arranged in one pixel area, and each light emitting unit comprises a light emitting device;

The color filter layer is arranged on one side of the plurality of light-emitting units, which is away from the substrate base plate; the color filter layer comprises a plurality of color resistance units and a black matrix arranged among the color resistance units; one color resistance unit is arranged in one pixel area; the black matrix is arranged in the non-display area; at least one light hole is arranged on the black matrix, and the light hole can transmit light emitted by one light emitting device.

Optionally, the extending direction of the light hole forms a preset angle with the substrate.

Optionally, the preset angle ranges from 15 ° to 80 °.

Optionally, the inner wall of the light hole is in a step shape.

Alternatively, the transmission holes for transmitting the same color light on the black matrix surrounding any one of the color group units are uniformly arranged.

Optionally, the color group units include a red color group unit, a green color group unit and a blue color group unit, and at least the transmission holes surrounding the red color group unit on the black matrix and transmitting red light are uniformly arranged.

Optionally, the light emitting device is an organic electroluminescent diode.

Optionally, the display substrate further includes an encapsulation layer, the encapsulation layer is disposed on a side of the plurality of light emitting units facing away from the substrate, and the color filter layer is disposed on a side of the encapsulation layer facing away from the substrate.

In a second aspect, an embodiment of the present disclosure provides a display device including the display substrate described above.

In a third aspect, an embodiment of the present disclosure provides a method for manufacturing a display substrate, where the display substrate includes a substrate, a plurality of light emitting units, and a color filter layer, and the method is characterized by including:

Forming a plurality of light emitting units on the substrate;

And forming a black matrix and a color resistance unit on one side of the plurality of light emitting units, which is away from the substrate, wherein the black matrix comprises at least one light hole.

Drawings

Fig. 1 is a schematic structural diagram of a display substrate according to an embodiment of the disclosure;

FIG. 2 is a cross-sectional view of a black matrix provided by an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of another display substrate according to an embodiment of the disclosure;

Fig. 4 is a schematic flow chart of forming the black matrix shown in fig. 2.

Detailed Description

In order that those skilled in the art will better understand the technical solutions of the present disclosure, the present disclosure will be described in further detail with reference to the accompanying drawings and detailed description.

Unless defined otherwise, technical or scientific terms used in this disclosure should be given the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The terms "first," "second," and the like, as used in this disclosure, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Likewise, the terms "a," "an," or "the" and similar terms do not denote a limitation of quantity, but rather denote the presence of at least one. 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.

In a first aspect, fig. 1 is a schematic structural diagram of a display substrate according to an embodiment of the present disclosure, as shown in fig. 1, where the display substrate has pixel areas AA arranged in an array, and a non-display area BB surrounding the pixel areas AA. The display substrate includes a substrate 11, a plurality of light emitting units 12, and a color filter layer 13.

Specifically, a plurality of light emitting units 12 are disposed on the substrate 11, and one light emitting unit 12 is disposed in one pixel area AA, and each light emitting unit 12 includes a light emitting device. The embodiments of the present disclosure will be described by taking the light emitting unit as an organic electroluminescent diode OLED as an example. In the embodiment of the present disclosure, the light emitting devices may include a red light emitting device 121, a green light emitting device 122, and a blue light emitting device 123, that is, the pixel unit in the implementation of the present disclosure includes a red sub-pixel, a green sub-pixel, and a blue sub-pixel. Of course, the light emitting device may be a device of other colors and types, and is not particularly limited herein.

Further, as shown in fig. 1, in the present embodiment, the color filter layer 13 is disposed on a side of the plurality of light emitting units 12 facing away from the substrate 11, the color filter layer 13 includes a plurality of color blocking units 131 and a black matrix 132 disposed between the color blocking units 131, one color blocking unit 131 is disposed in one pixel area AA, and the black matrix 132 is disposed in the non-display area BB.

The color blocking unit 131 may include a plurality of filters (not shown) capable of transmitting light of different colors, and the filters are correspondingly disposed on the light emitting side of each light emitting unit 12. The filter should enable the light of the corresponding color emitted by the light emitting unit below the projection to be transmitted, so that the color emitted by the light emitting unit is the same as the color allowed to transmit by the filter arranged on the light emitting side of the light emitting unit. For example, when the light emitting unit 12 is composed of a red light emitting device, a green light emitting device, and a blue light emitting device, the filter provided on the light emitting side of the red light emitting device is a red filter, that is, only red light is allowed to pass therethrough, the filter provided on the light emitting side of the green light emitting device is a green filter, only green light is allowed to pass therethrough, and the filter provided on the light emitting side of the blue light emitting device is a blue filter, only blue light is allowed to pass therethrough. The corresponding relation between the light emitting unit and the corresponding optical filter is only required to enable the light emitted by the light emitting unit to penetrate through the corresponding optical filter and exit, and the light emitting unit is not strictly limited to be completely corresponding in shape in the embodiment of the invention. In this case, the projection boundary of the filter on the light emitting unit may be slightly smaller than the size of the light emitting unit or slightly larger than the size of the light emitting unit, for example.

Further, as shown in fig. 1, in the present embodiment, at least one light transmitting hole 14 is provided on the black matrix 132, and the light transmitting hole 14 is capable of transmitting light emitted from one light emitting device. By providing the light holes 14 on the black matrix 132, the light output of the pixels at a large viewing angle can be improved, and thus the problem that the luminance of the display device is too fast in decay at a large viewing angle can be solved.

The light emitting unit 12 may include an anode, a cathode, and a light emitting layer between the anode and the cathode, and the light emitting layer includes an organic light emitting layer or a quantum dot light emitting layer, and the light emitting layer is exemplified as an organic light emitting layer. The organic functional layer sequentially comprises a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and an electron injection layer along the anode layer towards the cathode layer. Wherein the hole injection layer is adjacent to the anode layer and the electron injection layer is adjacent to the cathode layer. The anode is used as a connecting layer of forward voltage of the organic electroluminescent device, and has good conductivity, light transmittance in a visible light region and high work function. The anode is typically made of inorganic metal oxides (e.g., indium Tin Oxide (ITO), zinc oxide (ZnO), etc.), organic conductive polymers (e.g., poly 3, 4-ethylenedioxythiophene/polystyrene sulfonate (PEDOT: PSS), polyaniline (PANI), etc.), or high work function metallic materials (e.g., gold, copper, silver, platinum, etc.). The material of the hole injection layer includes any one of 2,3,6,7,10, 11-hexacyano-1, 4,5,8,9, 12-hexaazabenzophenanthrene (HAT-CN), 2,3,5, 6-tetrafluoro-7, 7', 8' -tetracyanodimethyl p-benzene (F4-TCNQ), and ammonium tris (4-bromophenyl) hexachloroantimonate (TBAHA). The hole transport layer may be made of an aromatic diamine compound, a triphenylamine compound, an aromatic triamine compound, a biphenyldiamine derivative, a triarylamine polymer, a metal complex, or a carbazole polymer, and is preferably: any one of N, N '-bis (1-naphthyl) -N, N' -diphenyl-1, 1 '-biphenyl-4-4' -diamine (NPB), triphenyldiamine derivative (TPD), TPTE, 1,3, 5-tris (N-3-methylphenyl-N-phenylamino) benzene (TDAB). The material of the electron transport layer 6 includes any one of 2- (4-biphenyl) -5-Phenyloxadiazole (PBD), 2, 5-bis (1-naphthyl) -1,3, 5-oxadiazole (BND), and 2,4, 6-triphenoxy-1, 3, 5-Triazine (TRZ). The material of the electron injection layer 7 is any one of lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, lithium oxide, and lithium metaborate. The cathode is used as a connecting layer of negative voltage of the organic electroluminescent device, and has good conductivity and low work function; the cathode typically employs a low work function metallic material such as: lithium, magnesium, calcium, strontium, aluminum, indium, etc. or alloys of the above metals with copper, gold, silver; or a very thin buffer insulating layer (such as lithium fluoride LiF, cesium carbonate CsCO3, etc.) and the metal or alloy.

For the electroluminescent display device, it is also classified into top emission and bottom emission according to the light emitting direction thereof, and those skilled in the art will recognize that the top emission and the bottom emission are only due to the change in the positional relationship between the cathode and the anode with respect to the light emitting layer, and the light emitting principles thereof are the same. The top emission will be described below as an example.

In some embodiments, the substrate base plate 11 includes: a substrate; a buffer layer disposed on a surface of the substrate; an active layer disposed on a surface of the buffer layer remote from the substrate; a gate insulating layer disposed on a surface of the buffer layer remote from the substrate, the gate insulating layer covering the active layer; a gate electrode disposed on a surface of the gate insulating layer remote from the substrate; an interlayer dielectric layer arranged on the surface of the gate insulating layer far from the substrate and covering the gate; the source electrode and the drain electrode are arranged on the surface of the interlayer dielectric layer far away from the substrate and are respectively and electrically connected with the active layer through the via hole; and the flat layer is arranged on the surface of the interlayer dielectric layer far away from the substrate and covers the source electrode and the drain electrode.

It should be noted that, the material of the base is not particularly limited, and may be a glass substrate or a flexible substrate, and when the base in the embodiment of the present invention is a flexible substrate, the bending and even folding functions may be conveniently realized. It should be appreciated by those skilled in the art that the substrate 11 shown in fig. 1 at least includes a flexible or glass substrate body and a back plate for emitting light of a plurality of light emitting units and a protection component thereof fabricated on the substrate, wherein the back plate may be an LTPS back plate, an Oxide back plate, or an organic TFT back plate, for example, and the protection component is bonded to the substrate 11 through a pressure sensitive adhesive or an optically transparent adhesive, and the fabrication material of the protection component may be Polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyurethane (PU), polycarbonate (PC), or the like.

In some embodiments, as shown in fig. 1, the display substrate further includes an encapsulation layer 15, where the encapsulation layer 15 is disposed on a side of the plurality of light emitting units 12 facing away from the substrate 11, and the color filter layer 13 is disposed on a side of the encapsulation layer 15 facing away from the substrate 11. The packaging layer 15 mainly isolates the light-emitting unit 12 from the external environment, so as to prevent intrusion of moisture, harmful gas, dust and rays, prevent damage by external force, stabilize various parameters of the device, and further improve the service life of the display panel. The encapsulation layer may be an encapsulation film; or may be a package substrate. When the encapsulation layer is an encapsulation film, the number of layers of the encapsulation film included in the encapsulation layer is not limited, and the encapsulation layer may include one layer of the encapsulation film, or may include two or more layers of the encapsulation film stacked. In some embodiments, the encapsulation layer comprises three encapsulation films arranged one above the other.

In the case where the encapsulation layer 15 includes three encapsulation films stacked in this order, the material of the encapsulation film located in the middle layer may be an organic material, and the material of the encapsulation films located on both sides may be an inorganic material.

The organic material is not limited, and may be, for example, PMMA (polymethyl methacrylate). The inorganic material is not limited, and may be, for example, one or more of SiNx (silicon nitride), siOx (silicon oxide), or SiOxNy (silicon oxynitride).

On this basis, the encapsulation film located in the intermediate layer can be manufactured by using an Ink Jet printing process (Ink Jet Printer, abbreviated as IJP). In addition, the encapsulation films on both sides may be respectively fabricated using a chemical vapor deposition method (Chemical Vapor Deposition, CVD for short).

In some embodiments, in order to prevent ambient light from passing through the light holes and increasing the reflectivity of the display substrate, as shown in fig. 1, the extending direction of the light holes 14 may be at a predetermined angle with respect to the substrate 11, i.e. the light holes 14 are disposed obliquely with respect to the horizontal substrate 11. Therefore, by obliquely arranging the light-transmitting holes 14, ambient light can be prevented from passing through the light-transmitting holes 14 to increase the reflectivity of the display substrate, and meanwhile, light rays with large viewing angles emitted by the light-emitting device 14 can be emitted from the obliquely arranged light-transmitting holes, so that the light quantity of pixels under the large viewing angle is increased under the condition of reducing the reflectivity of the display substrate, and the problem that the brightness of the display device is attenuated too quickly under the large viewing angle is solved.

The preset angle can be selected in a certain range according to actual needs, and the range of the preset angle is 15-80 degrees. Preferably, the preset angle may be set to 30 °, 60 °, or 45 °.

In some embodiments, to further reduce the reflectivity of the display substrate, as shown in fig. 2, the inner walls of the light holes 14 may be configured to be stepped. As shown in fig. 2, since the inner wall of the light transmitting hole 14 is provided in a stepped shape, the entry of ambient light into the display substrate through the light transmitting hole 14 can be completely blocked under the front view angle; under the condition of large visual angle, the light rays of large visual angle emitted by the light emitting device 12 can be emitted from the inclined light transmission holes 14, so that the light quantity of pixels under the large visual angle is increased under the condition of reducing the reflectivity of the display substrate, and the problem that the brightness of the display device is attenuated too quickly under the large visual angle is solved.

In some embodiments, as shown in fig. 1, the light-transmitting holes 14, which are on the black matrix 132 surrounding any one color group cell 131 and transmit the same color light, are uniformly arranged. In the following description, taking the blue sub-pixel as an example, the transmission holes 14 surrounding the black matrix 132 of the blue group unit and transmitting the same color light are uniformly arranged, which means that the plurality of transmission holes 14 surrounding the black matrix 132 of the blue group unit and transmitting the same color light may be symmetrically arranged along the first direction (X direction in the drawing) or symmetrically arranged along the second direction (Z direction in the drawing) with the blue blocking unit as the center, where the first direction and the second direction intersect. Similarly, the arrangement of the light holes 14 in the black matrix 132 corresponding to the sub-pixels of the other colors is the same as the arrangement of the light holes 14 in the black matrix 132 corresponding to the blue sub-pixels.

In this embodiment, the light holes surrounding the black matrix of any color unit and transmitting the same color light are uniformly arranged, so that the light quantity of the light rays emitted from the large viewing angle with the same color in each pixel is consistent, and color shift under the large viewing angle is prevented.

In some embodiments, as shown in fig. 3, the color set unit 131 includes a red color set unit, a green color set unit, and a blue color set unit, and the transmission holes 14 transmitting red light are uniformly arranged on at least the black matrix 132 surrounding the red color set unit. For example, only the transmission holes 14 surrounding the black matrix 132 of the red group unit and transmitting red light are uniformly arranged, and the transmission holes 14 are not arranged on the black matrix 132 surrounding the green group unit and surrounding the blue group unit, so that the light output of the red sub-pixel is increased under a large viewing angle, and the light output of the blue sub-pixel and the green sub-pixel is unchanged under the large viewing angle, thereby weakening the phenomenon of the pixel blushing under the large viewing angle, and solving the color cast problem. Of course, the light holes 14 may be disposed on the black matrix 132 surrounding the other color resistors to change the color shift caused by the light of different colors, which is not illustrated here.

In a second aspect, an embodiment of the present disclosure provides a display device including the display substrate described above.

In a third aspect, an embodiment of the present disclosure provides a method for manufacturing a display substrate, for the display substrate described above, where the display substrate includes a substrate, a plurality of light emitting units, and a color filter layer, and the manufacturing of the display substrate includes:

S110, forming a plurality of light emitting units on the substrate.

S120, forming a black matrix and a color resistance unit pattern on one side of the plurality of light emitting units, which is away from the substrate, wherein the black matrix comprises at least one light hole.

In step S120, the black matrix layer is formed by a patterning process using a preset mask. As shown in fig. 4, 1, a first black matrix layer is coated, and a first black matrix pattern is obtained through processes such as exposure, development, etching, stripping and the like; 2. coating a second black matrix layer on the first black matrix pattern, and obtaining a second black matrix pattern through processes such as exposure, development, etching, stripping and the like; 3. and coating a third black matrix layer on the second black matrix pattern, and obtaining the third black matrix pattern through processes such as exposure, development, etching, stripping and the like. A black matrix structure is formed of the first black matrix pattern, the second black matrix pattern, and the third black matrix pattern. The black matrix structure 132 is a multi-layered black matrix structure having two sides resembling right triangles and a middle resembling an isosceles triangle (see fig. 2). Because the inner wall of the light transmitting hole 14 in the black matrix 132 is in a ladder shape, light cannot enter the light emitting unit under the front view angle, and the reflectivity of the screen is effectively reduced; under a large viewing angle, the gaps of the black matrixes of each layer enable light rays emitted by the light emitting device to pass through the gaps within a certain viewing angle range, so that brightness attenuation under the large viewing angle is reduced.

In some embodiments, high precision black matrix oblique punching may also be achieved using an infrared ultrafast laser. According to the horizontal distance from the light emitting sub-pixel to the black matrix punching position and the vertical distance from the light emitting unit to the black matrix, the laser inclined punching angle can be determined, and inclined holes with different angles can be punched on one black matrix in a segmented mode, so that brightness attenuation of corresponding angles can be regulated and controlled, and the device large-view character bias can be improved in a targeted mode.

It is to be understood that the above embodiments are merely exemplary embodiments employed to illustrate the principles of the present disclosure, however, the present disclosure is not limited thereto. Various modifications and improvements may be made by those skilled in the art without departing from the spirit and substance of the disclosure, and are also considered to be within the scope of the disclosure.

Claims (6)

1. A display substrate having pixel regions arranged in an array, and a non-display region surrounding the pixel regions; the display substrate is characterized by comprising:

A substrate base;

A plurality of light emitting units arranged on the substrate, wherein one light emitting unit is arranged in one pixel area, and each light emitting unit comprises a light emitting device;

The color filter layer is arranged on one side of the plurality of light-emitting units, which is away from the substrate base plate; the color filter layer comprises a plurality of color resistance units and a black matrix arranged among the color resistance units; one color resistance unit is arranged in one pixel area; the black matrix is arranged in the non-display area; a plurality of light holes are formed in the black matrix and used for transmitting light emitted by the light emitting device;

The light holes are obliquely arranged compared with the horizontal substrate base plate; the inner wall of the light hole is stepped;

The color resistance unit comprises a red color resistance unit, a green color resistance unit and a blue color resistance unit;

the light holes which encircle any color resistance unit on the black matrix and transmit the same color light are uniformly distributed, and the plurality of light holes which encircle the color resistance unit on the black matrix and transmit the same color light are symmetrical with each other along the direction in which the red color resistance unit, the green color resistance unit and the blue color resistance unit are sequentially arranged.

2. The display substrate according to claim 1, wherein light holes which transmit red light are uniformly arranged on at least the black matrix surrounding the red color resist unit.

3. The display substrate of claim 1, wherein the light emitting device is an organic electroluminescent diode.

4. The display substrate of claim 1, further comprising an encapsulation layer disposed on a side of the plurality of light emitting cells facing away from the substrate, the color filter layer disposed on a side of the encapsulation layer facing away from the substrate.

5. A display device comprising the display substrate according to any one of claims 1 to 4.

6. A method for manufacturing the display substrate according to any one of claims 1 to 4, the display substrate comprising a substrate, a plurality of light emitting units, and a color filter layer, comprising:

Forming a plurality of light emitting units on the substrate;

Forming a black matrix and a color resistance unit on one side of the plurality of light emitting units, which is away from the substrate, wherein the black matrix comprises a plurality of light holes, and the light holes are used for transmitting light emitted by the light emitting devices; the inner wall of the light hole is stepped;

The color resistance unit comprises a red color resistance unit, a green color resistance unit and a blue color resistance unit;

the light holes which encircle any color resistance unit on the black matrix and transmit the same color light are uniformly distributed, and the plurality of light holes which encircle the color resistance unit on the black matrix and transmit the same color light are symmetrical with each other along the direction in which the red color resistance unit, the green color resistance unit and the blue color resistance unit are sequentially arranged.