Display panel and manufacturing method for display panel
Patent Information
- Application Number
- PCT/CN2025/079865
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-28
- Publication Date
- 2026-09-03
Smart Images
Figure CN2025079865_03092026_PF_FP_ABST
Abstract
Description
Display panel and how to make a display panel Technical Field
[0001] This invention relates to the field of display technology, and more particularly to a display panel and a method for manufacturing the display panel. Background Technology
[0002] Thin Film Transistor-Liquid Crystal Display (TFT-LCD) has a variety of commonly used display modes, such as Twisted Nematic (TN) display mode, Vertical Alignment (VA) display mode, Fringe Field Switching (FFS) display mode, and In-Plane Switching (IPS) display mode. Summary of the Invention
[0003] This disclosure provides a display panel and a method for manufacturing the display panel. The display panel includes:
[0004] An array substrate includes: a first substrate, an electrode structure located on one side of the first substrate, and a first alignment layer located on the side of the electrode structure opposite to the first substrate; wherein the electrode structure includes: a pixel electrode layer and a common electrode layer;
[0005] The opposing substrate includes: a second substrate, and a second alignment layer located on the side of the second substrate facing the array substrate;
[0006] An alignment layer is located between the array substrate and the opposing substrate. The alignment layer includes: a liquid crystal layer, a first polymer layer located on the side of the liquid crystal layer facing the array substrate, and a second polymer layer located on the side of the liquid crystal layer facing the opposing substrate; wherein the first polymer layer and the second polymer layer are formed by irradiating reactive monomers mixed in the liquid crystal layer with ultraviolet light; the horizontal electric field formed by the pixel electrode layer and the common electrode layer is used to drive the liquid crystal layer to rotate.
[0007] In one possible implementation, the materials of the first alignment layer and the second alignment layer comprise photoisomeric polyimide.
[0008] In one possible implementation, the materials of the first alignment layer and the second alignment layer include:
[0009] In one possible implementation, the pixel electrode layer includes: a plurality of pixel electrodes; the pixel electrodes include a first axis extending along a first direction and passing through the center of the pixel electrode;
[0010] The pixel electrode includes: a plurality of slits arranged along the first direction; the slits include: a first sub-slit portion located on one side of the first axis, and a second sub-slit portion located on the other side of the first axis.
[0011] This disclosure also provides a display device, which includes the display panel as described in this disclosure.
[0012] This disclosure also provides a method for manufacturing a display panel, comprising:
[0013] An array substrate having a first alignment layer and an opposing substrate having a second alignment layer are formed.
[0014] Ultraviolet light is used to perform photo-alignment on the first alignment layer of the array substrate and the second alignment layer of the opposing substrate;
[0015] Liquid crystal mixed with reactive monomers is injected between the array substrate and the opposing substrate, and the array substrate and the opposing substrate are then bonded together to form a display panel;
[0016] The display panel is irradiated with ultraviolet light so that the reactive monomers form a first polymer layer on the surface of the first alignment layer facing the opposing substrate and a second polymer layer on the surface of the second alignment layer facing the array substrate.
[0017] In one possible implementation, aligning the first alignment layer of the array substrate and the second alignment layer of the opposing substrate using ultraviolet light includes:
[0018] Ultraviolet light, along with an open mask, is used to align the first alignment layer of the array substrate and the second alignment layer of the opposing substrate.
[0019] In one possible implementation, aligning the first alignment layer of the array substrate and the second alignment layer of the opposing substrate using ultraviolet light includes:
[0020] Ultraviolet light is used, specifically the 300nm–330nm ultraviolet polarized light band. The angle between the light irradiation angle and the acute angle formed by the first alignment layer is controlled to be within the range of 40°–60° for alignment, and the angle between the light irradiation angle and the acute angle formed by the second alignment layer is also controlled to be within the range of 40°–60° for alignment.
[0021] In one possible implementation, aligning the first alignment layer of the array substrate and the second alignment layer of the opposing substrate using ultraviolet light includes:
[0022] The first and second rows of ultraviolet lamps were used for simultaneous exposure, with the exposure illuminance controlled at 50 mW / cm². 2 ~70mw / cm 2 The exposure speed is 100mm / s to 160mm / s, and the exposure energy is 30mJ to 50mJ. The first alignment layer of the array substrate and the second alignment layer of the opposing substrate are aligned.
[0023] In one possible implementation, irradiating the display panel with ultraviolet light to form a first polymer layer on the surface of the first alignment layer facing the opposing substrate and a second polymer layer on the surface of the second alignment layer facing the array substrate includes:
[0024] Using 350nm~380nm and energy of 8J / cm 2 ~12J / cm 2 Unpolarized ultraviolet light is used, and the angle between the irradiation angle and the first substrate is controlled to be within the range of 80° to 100°, so that the reactive monomer forms a first polymer layer on the surface of the first alignment layer facing the opposing substrate, and a second polymer layer forms on the surface of the second alignment layer facing the array substrate.
[0025] In one possible implementation, irradiating the display panel with ultraviolet light includes:
[0026] The array substrate controlling the display panel is located on the side of the opposing substrate facing the ultraviolet light source, irradiating the display panel.
[0027] In one possible implementation, the step of injecting liquid crystal mixed with reactive monomers between the array substrate and the opposing substrate, and then bonding the array substrate and the opposing substrate to form a display panel, includes:
[0028] A mixture is formed in which the concentration of the reactive monomer in the liquid crystal ranges from 1800 ppm to 2200 ppm;
[0029] The mixture is injected between the array substrate and the opposing substrate, and the array substrate and the opposing substrate are then bonded together to form a display panel.
[0030] In one possible implementation, the array substrate having a first alignment layer and the opposing substrate having a second alignment layer include:
[0031] A photoisotropic polyimide film is coated on the surface of the array substrate as a first alignment layer, and a photoisotropic polyimide film is coated on the surface of the opposing substrate as a second alignment layer.
[0032] The first alignment film layer and the second alignment film layer are first cured at a temperature of 70℃~90℃;
[0033] The first alignment film and the second alignment film are cured a second time at a temperature of 220℃~250℃.
[0034] In one possible implementation, the display panel includes an ADS display panel or a VA display panel. Attached Figure Description
[0035] Figure 1 is a cross-sectional schematic diagram of a display panel provided in an embodiment of this disclosure;
[0036] Figure 2 is a schematic diagram of the pixel electrode provided in an embodiment of this disclosure;
[0037] Figure 3 is a schematic diagram of the manufacturing process of the display panel provided in the embodiment of this disclosure;
[0038] Figure 4A shows UV. 2 The incident angle of UV light on the exposure equipment for process A and the angle between the incident angle and the substrate;
[0039] Figure 4B is a schematic diagram showing that the direction of the alignment force is perpendicular to the direction of polarized light.
[0040] Figure 5 shows the UV provided in the embodiments of this disclosure. 2 A schematic diagram illustrating the production differences between Process A and ADS process;
[0041] Figure 6 shows a schematic diagram of three routes for the ADS process;
[0042] Figure 7 is a schematic diagram comparing the advantages and disadvantages of PI solutions in ADS process with different UV wavelengths.
[0043] Figure 8 is a simulation diagram comparing the alignment forces before and after adding RM to the liquid crystal;
[0044] Figure 9 is a schematic diagram comparing the differences between the two ADS optical alignment methods;
[0045] Figure 10 is a schematic diagram of the first UV alignment;
[0046] Figure 11 is a schematic diagram of the photoalignment direction and rotation direction of the positive liquid crystal;
[0047] Figure 12 is a schematic diagram of the negative liquid crystal photoalignment direction and the liquid crystal rotation direction;
[0048] Figure 13 is a schematic diagram of various alignment schemes for the first UV light irradiation;
[0049] Figure 14 is a schematic diagram showing the relationship between energy and residual RM concentration during the second UV light irradiation.
[0050] Figure 15 is a schematic diagram showing the relationship between energy, residual RM concentration, and afterimage appearance during the second UV irradiation.
[0051] Figure 16 is a schematic diagram of the second verification scheme and test results;
[0052] Figure 17 is a schematic diagram of the afterimage test results under the second verification of optimal conditions. Detailed Implementation
[0053] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.
[0054] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.
[0055] As used herein, “approximately” or “substantially the same” includes the stated value and means within an acceptable range of deviations from the specific value, as determined by a person skilled in the art taking into account the measurement in question and the errors associated with the measurement of the specific quantity (i.e., limitations of the measurement system). For example, “substantially the same” may mean a difference relative to the stated value within one or more standard deviations, or within ±30%, 20%, 10%, or 5%.
[0056] In the accompanying drawings, the thicknesses of layers, films, panels, regions, etc., are enlarged for clarity. Exemplary embodiments are described herein with reference to cross-sectional views that are schematic diagrams of idealized embodiments. Thus, deviations from the shapes shown in the drawings will be expected as a result of, for example, manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the regions shown herein, but rather include deviations in shape caused, for example, by manufacturing processes. For example, regions illustrated or described as flat may typically have rough and / or non-linear characteristics. Furthermore, sharp corners illustrated may be rounded. Thus, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shapes of the regions, nor are they intended to limit the scope of the claims.
[0057] To keep the following description of the embodiments of this disclosure clear and concise, detailed descriptions of known functions and known components are omitted.
[0058] UV 2 Ultraviolet Vertical Alignment (VA) is one of the mainstream vertical alignment technologies currently used to fabricate vertically aligned (VA) display panels. Compared to the horizontally aligned Advanced Super Dimension Switch (ADS) photoalignment technology, UV... 2 Process A possesses excellent properties such as high contrast and low dark-state light leakage, but due to the UV... 2 The four-domain display mode formed by process A exhibits dark lines between different domain directions and at domain edges. As resolution continues to improve, UV... 2 The transmittance loss in the A process becomes increasingly severe, while the ADS process shows no significant change. To meet customers' diverse needs for product performance such as resolution, transmittance, and contrast, and to overcome the limitations of UV... 2 The limitations of high-resolution products using the A process necessitate the development of ADS-compatible technologies. In other words, currently, UV... 2 The equipment used in process A is only used for VA display panel manufacturing, limiting its application scope, and it also employs UV coating. 2 When the alignment liquid corresponding to the light source of device A is aligned, there is a risk of image retention due to weak alignment force during display.
[0059] In view of this, the present disclosure provides a display panel, as shown in FIG1, including:
[0060] The array substrate 1 includes: a first substrate 11, an electrode structure 12 located on one side of the first substrate 11, and a first alignment layer 13 located on the side of the electrode structure 12 facing away from the first substrate 11; wherein, the electrode structure 12 includes: a pixel electrode layer 121 and a common electrode layer 122 (the common electrode may include slits); in Figure 1, it is shown that the pixel electrode layer is disposed between the common electrode layer and the first substrate. Optionally, the common electrode may be disposed between the pixel electrode (the pixel electrode includes slits) and the first substrate, or the pixel electrode and the common electrode may be disposed in the same layer, and both the pixel electrode and the common electrode include multiple branch electrodes and slits.
[0061] The opposing substrate 2 includes: a second substrate 21, and a second alignment layer 22 located on the side of the second substrate 21 facing the array substrate 1;
[0062] Alignment layer 3 is located between array substrate 1 and opposing substrate 2. Alignment layer 3 includes: liquid crystal layer 31, a first polymer layer 321 located on the side of liquid crystal layer 31 facing array substrate 1, and a second polymer layer 322 located on the side of liquid crystal layer 31 facing opposing substrate 2; wherein, the first polymer layer 321 and the second polymer layer 322 are formed by ultraviolet light irradiation of reactive monomers mixed in liquid crystal layer 31; the horizontal electric field formed by pixel electrode layer 121 and common electrode layer 122 is used to drive liquid crystal layer 31 to rotate.
[0063] In this embodiment, the array substrate 1 of the display panel includes a pixel electrode layer 121 and a common electrode layer 122. The horizontal electric field formed by the pixel electrode layer 121 and the common electrode layer 122 is used to drive the liquid crystal layer 31 to rotate. The display panel is an ADS panel and can use UV... 2 Equipment A is manufactured to broaden UV radiation. 2 Application of device A; In addition, the alignment layer 3 includes: a liquid crystal layer 31, a first polymer layer 321, and a second polymer layer 322; wherein, the first polymer layer 321 and the second polymer layer 322 are formed by ultraviolet light irradiation of reactive monomers mixed in the liquid crystal layer 31, that is, by using UV... 2 When equipment A manufactures a display panel, reactive monomers can be mixed into the liquid crystal. When irradiated with ultraviolet light, these reactive monomers polymerize with surrounding reactive monomers to form macromolecules. These macromolecules then aggregate on the surface of the first alignment layer through diffusion, thereby strengthening the alignment force. A first polymer layer 321 is formed on the surface of the first alignment layer 13, and a second polymer layer 322 is formed on the surface of the second alignment layer 22. This strengthens the alignment force with the liquid crystal layer 31 and improves the transmission of UV light. 2 When device A forms an ADS display panel, it uses UV... 2 The alignment liquid corresponding to the light source of device A has weak alignment force, which poses a risk of image retention during display.
[0064] In one possible implementation, the materials of the first alignment layer 13 and the second alignment layer 22 include photoisomerizable polyimide. In this embodiment of the present disclosure, the materials of the first alignment layer 13 and the second alignment layer 22 include photoisomerizable polyimide, which can prevent the generation of decomposition products during photoalignment and avoid affecting the normal display of the display panel.
[0065] In one possible implementation, the materials of the first alignment layer 13 and the second alignment layer 22 include:
[0066] In one possible implementation, referring to FIG2, an example of pixel electrodes having slits is provided. The pixel electrode layer 121 includes: a plurality of pixel electrodes 120; the pixel electrodes 120 include a first axis k1 extending along a first direction X and passing through the center of the pixel electrode 120; the pixel electrodes 120 include: a plurality of slits S arranged along the first direction X; the slits S include: a first sub-slit portion S1 located on one side of the first axis k1, and a second sub-slit portion S2 located on the other side of the first axis k1.
[0067] Based on the same inventive concept, embodiments of this disclosure also provide a display device, which includes a display panel as provided in embodiments of this disclosure.
[0068] UV 2 Ultraviolet Vertical Alignment (VA) is one of the mainstream vertical alignment technologies currently used to fabricate vertically aligned (VA) display panels. Compared to the horizontally aligned Advanced Super Dimension Switch (ADS) photoalignment technology, UV... 2 Process A possesses excellent properties such as high contrast and low dark-state light leakage, but due to the UV... 2 The four-domain display mode formed by process A exhibits dark lines between different domain directions and at domain edges. As resolution continues to improve, UV... 2 The transmittance loss in the A process becomes increasingly severe, while the ADS process shows no significant change. To meet customers' diverse needs for product performance such as resolution, transmittance, and contrast, and to overcome the limitations of UV... 2 The limitations of high-resolution products using the A process necessitate the development of ADS-compatible technologies. In other words, currently, UV... 2 The equipment used in process A is only used for VA display panel manufacturing, limiting its application scope, and it also employs UV coating. 2 When the alignment liquid corresponding to the light source of device A is aligned, there is a risk of image retention due to weak alignment force during display.
[0069] In view of this, the present disclosure also provides a method for manufacturing a display panel, as shown in FIG3, including:
[0070] Step S100: Form an array substrate having a first alignment layer and an opposing substrate having a second alignment layer; wherein, the array substrate may include an electrode structure; the electrode structure includes: a pixel electrode layer and a common electrode layer (the pixel electrode layer and the common electrode layer may be disposed in the same layer or in different layers); that is, the structure of the array substrate is an ADS structure, and the horizontal electric field formed by the pixel electrode layer and the common electrode layer is used to drive the liquid crystal layer to rotate.
[0071] Optionally, step S100, forming an array substrate having a first alignment layer and an opposing substrate having a second alignment layer, may include:
[0072] Step S110: Coat the surface of the array substrate with an optically heterogeneous polyimide film as the first alignment film layer, and coat the surface of the opposing substrate with an optically heterogeneous polyimide film as the second alignment film layer.
[0073] Step S120: The first alignment film layer and the second alignment film layer are first cured at a temperature of 70℃~90℃; Optionally, the first alignment film layer and the second alignment film layer can be first cured at a temperature of 70℃, 80℃ or 90℃.
[0074] Step S130: The first alignment film layer and the second alignment film layer are cured a second time at a temperature of 200℃ to 250℃. Optionally, the first alignment film layer and the second alignment film layer can be cured a second time at a temperature of 200℃, 210℃, 220℃, 230℃, 240℃, or 250℃. Optionally, the thickness of the first alignment film layer after curing is in the range of 100nm to 120nm; the thickness of the second alignment film layer after curing is in the range of 100nm to 120nm.
[0075] Step S200: Photoalign the first alignment layer of the array substrate and the second alignment layer of the opposing substrate using ultraviolet light; this can be achieved through UV light. 2 A process exposure equipment, using UV 2 In process A exposure equipment, ultraviolet light performs photo-alignment on the first alignment layer of the array substrate and the second alignment layer of the opposing substrate.
[0076] Optionally, it can be based on UV. 2 A process exposure equipment uses linearly polarized light in the 313nm band to perform photo-alignment of the first alignment layer and the second alignment layer of the opposing substrate, with an energy of 40mJ / cm². 2Referring to the device structure shown in Figure 4A, the angle between the UV light irradiation angle and the substrate on the vertical plane is 50°, and the polarization direction is parallel to the substrate photoalignment direction. As shown in Figure 4B, a horizontal alignment force perpendicular to the polarization direction is finally obtained.
[0077] Step S300: Inject liquid crystal mixed with reactive monomers between the array substrate and the opposing substrate, and then bond the array substrate and the opposing substrate together to form a display panel;
[0078] Optionally, step S300, which involves injecting liquid crystal mixed with reactive monomers between the array substrate and the opposing substrate, and bonding the array substrate and the opposing substrate to form a display panel, includes:
[0079] Step S310: Form a mixture in which the concentration of the reactive monomer in the liquid crystal is in the range of 1800ppm to 2200ppm; this can make the residual concentration of the reactive monomer after irradiation relatively small, avoiding the problem of severe image retention on the display panel when the residual concentration of the reactive monomer after irradiation is relatively large; optionally, the concentration of the reactive monomer in the liquid crystal can be 1800ppm, 1900ppm, 2000ppm, 2100ppm, or 2300ppm;
[0080] Step S320: Inject a mixture between the array substrate and the opposing substrate, and then bond the array substrate and the opposing substrate together to form a display panel.
[0081] Step S400: Irradiate the display panel with ultraviolet light so that the reactive monomers form a first polymer layer on the surface of the first alignment layer facing the opposing substrate and a second polymer layer on the surface of the second alignment layer facing the array substrate.
[0082] Optionally, regarding step S400, irradiating the display panel with ultraviolet light to form a first polymer layer on the surface of the first alignment layer facing the opposing substrate and a second polymer layer on the surface of the second alignment layer facing the array substrate, may include: using 350nm to 380nm light with an energy of 8J / cm². 2 ~12J / cm 2 Unpolarized ultraviolet light is used, and the angle between the irradiation angle and the first substrate is controlled to be within the range of 80° to 100°, so that the reactive monomers form a first polymer layer on the surface of the first alignment layer facing the opposing substrate, and a second polymer layer on the surface of the second alignment layer facing the opposing substrate. Since the second ultraviolet light irradiation is to polymerize the reactive monomers in the liquid crystal layer, unpolarized ultraviolet light can be used, unlike the linearly polarized ultraviolet light required for alignment of the alignment layer. Optionally, the angle between the irradiation angle and the first substrate can be 90°.
[0083] Optionally, step S400, irradiating the display panel with ultraviolet light, includes: controlling the array substrate of the display panel to be located on the side of the opposing substrate facing the ultraviolet light source, and irradiating the display panel. This is to avoid the situation where, when the opposing substrate faces the ultraviolet light source, the color resist layer, which is usually provided on the opposing substrate, may block the entry of ultraviolet light, thereby affecting the polymerization of the reactive monomers.
[0084] In this embodiment of the disclosure, UV coating is applied to the display panel of the ADS structure. 2 A-process exposure equipment can be used for alignment, which can broaden the UV spectrum. 2 Application of Device A; Furthermore, by injecting liquid crystal mixed with reactive monomers between the array substrate and the opposing substrate, and irradiating the display panel with ultraviolet light, the reactive monomers form a first polymer layer on the surface of the first alignment layer facing the opposing substrate, and a second polymer layer on the surface of the second alignment layer facing the array substrate. That is, reactive monomers are mixed in the liquid crystal. When irradiated with ultraviolet light, these reactive monomers polymerize with surrounding reactive monomers to form macromolecules. These macromolecules aggregate on the surface of the first alignment layer through diffusion, thereby strengthening the alignment force. A first polymer layer 321 is formed on the surface of the first alignment layer 13, and a second polymer layer 322 is formed on the surface of the second alignment layer 22. This strengthens the alignment force with the liquid crystal layer 31 and improves the performance of the display panel under UV light. 2 When device A forms an ADS display panel, it uses UV... 2 The alignment liquid corresponding to the light source of device A has weak alignment force, which poses a risk of image retention during display.
[0085] In one possible implementation, step S200, aligning the first alignment layer of the array substrate and the second alignment layer of the opposing substrate with ultraviolet light, includes: aligning the first alignment layer of the array substrate and the second alignment layer of the opposing substrate with ultraviolet light and an open mask.
[0086] In this embodiment of the disclosure, when using UV... 2 When fabricating an ADS display panel using process A exposure equipment, an aperture mask is used to align the first alignment layer of the array substrate and the second alignment layer of the opposing substrate, while conventional UV... 2 When forming a VA display panel using process A exposure, a mask with pixel-level openings is required, while the embodiments disclosed herein use UV... 2 A process exposure equipment, but it is used to produce ADS display panels. This type of mask is not required. Only an open mask is needed to align the ADS display panels.
[0087] In one possible implementation, referring to Figures 4A and 4B, step S200, aligning the first alignment layer of the array substrate and the second alignment layer of the opposing substrate using ultraviolet light, includes: using ultraviolet light, selecting a 300nm–330nm ultraviolet polarized light band, and controlling the angle between the light irradiation angle and the acute angle α formed with the first alignment layer to be within the range of 40°–60° for alignment, and controlling the angle between the light irradiation angle and the acute angle α formed with the second alignment layer to be within the range of 40°–60° for alignment. Optionally, a 313nm linearly polarized light band can be used. Optionally, the acute angle α formed by the light irradiation angle and the first alignment layer is 50°; the acute angle α formed by the light irradiation angle and the second alignment layer is 50°.
[0088] In this embodiment of the present disclosure, linearly polarized ultraviolet light can be used when performing photoalignment on the first alignment layer and the second alignment layer, so as to achieve the desired pretilt angle for the liquid crystal.
[0089] In one possible implementation, step S200, aligning the first alignment layer of the array substrate and the second alignment layer of the opposing substrate using ultraviolet light, includes: simultaneously exposing the first and second rows of ultraviolet lamps to ultraviolet light, and controlling the exposure illuminance to 50 mw / cm². 2 ~70mw / cm 2 The exposure speed is 100mm / s to 160mm / s, and the exposure energy is 30mJ to 50mJ. The first alignment layer of the array substrate and the second alignment layer of the opposing substrate are aligned.
[0090] In this embodiment, the first and second rows of ultraviolet lamps are used for simultaneous exposure, and the exposure illuminance is controlled at 50 mw / cm². 2 ~70mw / cm 2 With an exposure speed of 100mm / s to 160mm / s and an exposure energy of 30mJ to 50mJ, the first alignment layer of the array substrate and the second alignment layer of the opposing substrate are aligned. The number of exposures is minimized and the time is shortest, which can optimize the overall production capacity and operational convenience.
[0091] In one possible implementation, the display panel provided in this disclosure may include an ADS display panel or a VA display panel. That is, the manufacturing method of the display panel provided in this disclosure can be used to manufacture either an ADS display panel or a VA display panel.
[0092] To better understand the inventive concept of the embodiments of this disclosure, the following further supplementary explanations are provided:
[0093] Conventional UV2A photoalignment technology is a pixel-level scanning exposure technology. By using the light-blocking and light-transmitting areas configured on the mask, the alignment films of the array substrate and the color filter substrate are aligned with opposite polarization directions in the corresponding pixel areas, achieving a display effect of 4 or more pixels after assembly. Specifically, the photomask is mounted on two stages. One sub-pixel unit corresponds to the light-shielding area and the light-transmitting area on different stages. The size of the light-shielding area and the light-transmitting area configured on the photomask is approximately half the size of a sub-pixel. An adjacent light-shielding area plus a light-transmitting area corresponds to one sub-pixel unit. The light alignment polarization direction is horizontal to the pixel scanning direction, and the light alignment polarization directions of the two stages are opposite. The array substrate TFT and the opposing substrate CF have the same light alignment method, but the sub-pixel light alignment directions are different. After assembly and bonding, the liquid crystal orientations on the array substrate TFF and the color filter substrate CF are different in different domains. The liquid crystal rotates in an orderly manner in the cell, forming a unique UV2A display mode. The theoretically calculated light amount of the array substrate TFF and the color filter substrate CF is the same. The azimuth angle of the liquid crystal in different domains is 45° with the polarization axis of the TFT / CF. At this time, the transmittance of the VA product is the highest.
[0094] Based on current UV 2 Considering the factors of cost reduction, the ADS process was chosen as the development direction for UV exposure equipment. 2 The vertical alignment technique (ADS) uses 313nm ultraviolet light and a mask to perform micron-level sub-pixel segmentation and alignment, causing phototactic molecules in the vertical alignment liquid coated on the substrate surface to align orient themselves, thereby controlling the tilting of liquid crystal molecules. In contrast, the ADS process does not require micron-level alignment precision; it only requires uniform alignment of the entire substrate in a single direction, causing phototactic molecules in the horizontal alignment liquid coated on the substrate surface to align orient themselves. Combined with the electric field force of the slits in the array substrate, this controls the rotation of liquid crystal molecules. Therefore, UV... 2 The A-process exposure equipment demonstrates the feasibility of ADS process production. Figure 5 is based on UV... 2 A process exposure equipment for UV exposure 2 Analysis of the differences between A process and ADS process;
[0095] Based on the wavelength range of UV lamps, the ADS process mainly includes three process routes: 254nm, 313nm, and 365nm. (Compared to UV...) 2 Process A's UV lamp band is 313nm, which cannot be used for alignment liquid alignment in 254nm and 365nm process routes. Furthermore, compared to the 254nm and 365nm process routes, the 313nm process requires more sophisticated UV switching techniques. 2Both A and ADS production modes do not require changing the UV lamp, and no additional drying process is needed after alignment with the alignment solution, resulting in lower operating costs and a cleaner, more environmentally friendly process. Considering the lowest implementation cost and the optimal subsequent production and operation method, the 313nm route was chosen for ADS process development. Figure 6 introduces the three routes of the ADS process;
[0096] The alignment liquid corresponding to 313nm can be applied to both vertical and horizontal alignment modes, with vertical alignment UV... 2 Process A utilizes the molecular side chains in the alignment solution for alignment, while the horizontal alignment ADS process utilizes the molecular backbone in the alignment solution. The advantage of the 313nm alignment solution is that it produces no decomposition products during photoalignment as an isomeric alignment solution, but its risk lies in the weaker alignment force, which poses a risk of image retention. Figure 7 compares the advantages and disadvantages of alignment solutions in different UV wavelength ADS processes. To address the image retention issue, reactive monomers (RMs) are added to the liquid crystal. After the array substrate and the opposing substrate are bonded, UV irradiation is performed again. This UV irradiation uses unpolarized UV light. After being irradiated by UV light, the RM monomers in the liquid crystal polymerize with surrounding monomers to form macromolecules. The polymerized RM macromolecules aggregate on the surface of the alignment layer through diffusion, thereby strengthening the alignment force. The alignment force simulation before and after adding RMs to the liquid crystal is shown in Figure 8.
[0097] The method for manufacturing the display panel in this embodiment may include the following:
[0098] Alignment liquid coating: First, photoheterogeneous alignment liquid is coated on the surface of the array substrate and the opposing substrate. Then, the array substrate and the opposing substrate are heated at 80°C to pre-cur the alignment liquid solvent. Finally, the array substrate and the opposing substrate are heated at 230°C for formal curing. After curing, the alignment film thickness is 115nm.
[0099] First UV exposure: The first UV exposure based on UV 2 Process A exposure equipment utilizes linearly polarized light in the 313nm band to perform photo-alignment of the alignment solution, with an energy of 40mJ / cm². 2 Referring to the device structure shown in Figure 4A, the angle between the UV light irradiation angle and the substrate on the vertical plane is 50°, and the polarization direction is parallel to the substrate photoalignment direction. As shown in Figure 4B, a horizontal alignment force perpendicular to the polarization direction is finally obtained.
[0100] Second UV irradiation: After the first UV irradiation, the array substrate and the opposing substrate are first coated with sealant, then liquid crystal containing photoreactive monomer RM (RM content 2000ppm) is dropped in. Next, the substrates are bonded together, and finally, the bonded substrates are irradiated twice with 365nm unpolarized UV light at an energy of 10J / cm². 2The angle between the UV light irradiation angle and the substrate on the vertical plane is 90°. At this time, the array substrate surface needs to be on top and close to the UV lamp, and the opposite substrate surface needs to be on the bottom and away from the UV lamp.
[0101] Further explanation regarding the first violet light exposure is as follows:
[0102] Conventional ADS process for photoalignment and the use of UV 2 The main differences in photoalignment using process equipment A are in terms of equipment structure, process parameters, and exposure methods, as shown in Figure 9.
[0103] Unlike in UV 2 The A process only performs alignment after PI liquid coating, while the 313nm ADS process requires two UV irradiation processes. The first UV irradiation determines the alignment direction, and the second UV irradiation enhances the alignment force.
[0104] The first UV irradiation process is performed after the PI solution is coated, using UV... 2 A process exposure equipment uses a 313nm UV lamp with a polarizing plate to orient the phototactic molecules in the PI liquid. The corresponding alignment scheme is selected according to the type of liquid crystal used (positive liquid crystal or negative liquid crystal). Figure 10 is a schematic diagram of the alignment scheme based on positive and negative liquid crystals for the first UV exposure.
[0105] The sub-pixel Slit electrode design is shown in Figures 11 and 12. The Slit electrodes in the two domains are designed in a fishbone shape. The angle between the long side of the Slit electrode and the initial direction of the liquid crystal, i.e. the direction of the alignment force, is 5° (which can be adjusted according to actual needs). The width L of the Slit electrode is 3μm, the distance S between the electrodes is 3μm, and the direction of the horizontal electric field force formed by the electrodes is perpendicular to the long side of the Slit electrode.
[0106] The characteristic of positive liquid crystal is that when energized, the liquid crystal molecules will rotate in the direction of the electric field force. In the dark state, the direction of the electric field force on the long axis of the liquid crystal is perpendicular, and in the bright state, the direction of the long axis of the liquid crystal is parallel to the direction of the electric field force. Figure 11 shows the alignment direction of the positive liquid crystal TFT substrate and CF substrate, the initial direction of the liquid crystal, and the direction of the electric field force and the rotation direction of the liquid crystal after energization.
[0107] The characteristic of negative liquid crystal is that when energized, the liquid crystal molecules will rotate in the direction of the electric field force. In the dark state, the direction of the electric field force on the long axis of the liquid crystal is parallel, and in the bright state, the direction of the long axis of the liquid crystal is perpendicular to the direction of the electric field force. Figure 12 shows the alignment direction of the negative liquid crystal array substrate and the opposing substrate, the initial direction of the liquid crystal, and the direction of the electric field force and the rotation direction of the liquid crystal after energization.
[0108] As mentioned earlier, since the 313nm ADS process uses a horizontally oriented PI solution and utilizes the main chain for alignment, only unidirectional polarized light irradiation is needed during the first UV alignment.2 The specific alignment scheme of the photo-alignment equipment for process A is shown in Figure 13;
[0109] Option 1: The array substrate and the opposing substrate are cast in the same direction, with a gap of 500μm between the dummy mask and the substrate (array substrate / opposing substrate), and exposure is completed in one exposure. The first row of lamps is used for exposure, with an exposure illuminance of 65mw / cm². 2 Exposure speed 65mm / s, exposure energy 40mJ;
[0110] Option 2: The array substrate and the opposing substrate are exposed in the same direction. The gap between the dummy mask and the substrate (array substrate / opposing substrate) is 500μm. The exposure is completed in one exposure. A second row of lamps is used for exposure, with an exposure illuminance of 65mw / cm². 2 Exposure speed 65mm / s, exposure energy 40mJ;
[0111] Option 3: The array substrate and the opposing substrate are cast in the same direction. The gap between the dummy mask and the substrate (array substrate / opposing substrate) is 500μm. Two exposures are performed, using the first row of lamps for exposure, with an exposure illuminance of 65mw / cm². 2 Exposure speed 130mm / s, single exposure energy 20mj, total energy of two exposures 40mj;
[0112] Option 4: The array substrate and the opposing substrate are cast in the same direction. The gap between the dummy mask and the substrate (array substrate / opposing substrate) is 500μm. Two exposures are performed, using the second row of lamps for exposure, with an exposure illuminance of 65mw / cm². 2 Exposure speed 130mm / s, single exposure energy 20mj, total energy of two exposures 40mj;
[0113] Option 5: The array substrate and the opposing substrate are cast in the same direction. The gap between the dummy mask and the substrate (array substrate / opposing substrate) is 500μm. Two exposures are performed. The first exposure uses the first row of lamps, and the second exposure uses the second row of lamps. The exposure illuminance is 65mw / cm². 2 Exposure speed 130mm / s, single exposure energy 20mj, total energy of two exposures 40mj;
[0114] Option 6: The array substrate and the opposing substrate are cast in the same direction. The gap between the dummy mask and the substrate (array substrate / opposing substrate) is 500μm. Two exposures are performed. The first exposure uses the second row of lamps, and the second exposure uses the first row of lamps. The exposure illuminance is 65mw / cm². 2Exposure speed 130mm / s, single exposure energy 20mj, total energy of two exposures 40mj;
[0115] Option 7: The array substrate and the opposing substrate are exposed in the same direction. The gap between the dummy mask and the substrate (array substrate / opposing substrate) is 500μm. The exposure is completed in one exposure. The first row of lamps and the second row of lamps are exposed simultaneously. The exposure illuminance is 65mw / cm². 2 Exposure speed 130mm / s, exposure energy 40m;
[0116] In summary, all seven schemes can achieve UV-based results. 2 For the first UV irradiation of the photo-alignment equipment in process A, considering factors such as overall capacity and cost, option seven requires the fewest exposures and has the shortest time.
[0117] Further explanation regarding the second violet light exposure is as follows:
[0118] The second UV irradiation is performed after the substrate is bonded. This UV irradiation uses 365nm unpolarized UV light with an irradiation energy of 5J / cm². 2 The angle between the UV light irradiation angle and the substrate on the vertical plane is 90°. The array substrate surface needs to be on top and close to the UV lamp, while the opposite substrate surface needs to be on the bottom and away from the UV lamp.
[0119] When RM monomers in liquid crystal are exposed to UV irradiation, they polymerize with surrounding monomers to form macromolecules. The polymerized RM macromolecules aggregate on the surface of PI molecules through diffusion, thereby strengthening the alignment force.
[0120] The initial concentration of RM in the liquid crystal was 2500ppm. Experiments showed that the residual RM concentration in the liquid crystal was positively correlated with the second UV energy. As the UV energy increased, the residual RM concentration in the liquid crystal gradually decreased. The verification scheme is shown in Figure 14. At the same time, as the residual RM concentration gradually decreased, the image retention performance became better and better, as shown in Figure 15.
[0121] The initial verification of optimal image retention conditions showed that the recovered grayscale reached L170 after 120 hours of image retention testing, which failed to meet the required image retention specifications (168 hours, recovered grayscale < L127). To further optimize image retention performance, the solution was improved by reducing RM concentration. ① Increasing the energy of the second UV irradiation to promote further reaction of residual RM in the liquid crystal; ② Reviewing the reduction of the initial RM concentration in the liquid crystal to reduce the DC effect caused by residual RM.
[0122] The results of the second verification scheme and test are shown in Figure 16. Scheme 5 has an initial RM content of 2000ppm and the best image retention performance when the UV energy is 10J in the second test. Increasing the energy to 15J further deteriorates the image retention performance. Moreover, when the initial RM is further reduced to 1500ppm, the image retention performance also deteriorates at the same energy. It is speculated that the high-energy irradiation damages the molecular structure in the alignment film (PI) in the substrate, resulting in disordered alignment forces and poor image retention. The final image retention test results of Scheme 5 with an initial RM content of 2000ppm and a UV energy of 10J in the second test are shown in Figure 17, which meet the required specifications.
[0123] In summary, according to the test results, the image retention performance of Scheme 5 is best when the initial RM content of the liquid crystal is 2000ppm and the second UV energy is 10J.
[0124] In some embodiments, the display panel provided in this disclosure may further include a first polarizer on the side of the array substrate away from the opposing substrate, and a second polarizer on the side of the opposing substrate away from the array substrate, wherein the polarization direction of the first polarizer is perpendicular to the polarization direction of the second polarizer. Other essential components of the display panel are those which should be understood by those skilled in the art and will not be described in detail here, nor should they be construed as limiting the scope of this disclosure.
[0125] Based on the same inventive concept, this disclosure also provides a display device, comprising the display panel described above and a backlight module located on the light-incident side of the display panel. The backlight module can be a direct-lit backlight module or an edge-lit backlight module. Optionally, the edge-lit backlight module may include LED strips, stacked reflective sheets, light guide plates, diffusers, prism groups, etc., with the LED strips located on one side of the thickness direction of the light guide plate. The direct-lit backlight module may include a matrix light source, a reflective sheet, a diffuser plate, and a brightness enhancement film stacked on the light-emitting side of the matrix light source, with the reflective sheet including openings directly opposite the positions of the LEDs in the matrix light source. The LEDs in the LED strips and the LEDs in the matrix light source can be light-emitting diodes (LEDs), such as miniature LEDs (Mini LEDs, Micro LEDs, etc.).
[0126] Micro-LEDs, at the sub-millimeter or even micrometer scale, are self-emissive devices, just like organic light-emitting diodes (OLEDs). Like OLEDs, they offer a range of advantages, including high brightness, ultra-low latency, and ultra-wide viewing angles. Furthermore, because inorganic LEDs emit light based on more stable and lower-resistance metal semiconductors, they offer advantages over organic LEDs, such as lower power consumption, better resistance to high and low temperatures, and longer lifespan. When used as backlights, micro-LEDs can achieve more precise dynamic backlighting effects, effectively improving screen brightness and contrast while eliminating glare caused by traditional dynamic backlighting between bright and dark areas, thus optimizing the visual experience.
[0127] In some embodiments, the display device provided in this disclosure can be any product or component with display function, such as a projector, 3D printer, virtual reality device, mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, navigator, smartwatch, fitness wristband, or personal digital assistant. Optionally, the display device provided in this disclosure includes, but is not limited to, components such as a radio frequency unit, network module, audio output & input unit, sensor, display unit, user input unit, interface unit, and control chip. Optionally, the control chip is a central processing unit, digital signal processor, system-on-a-chip (SoC), etc. For example, the control chip may also include a memory, a power module, etc., and achieve power supply and signal input / output functions through additionally provided wires, signal lines, etc. For example, the control chip may also include hardware circuits and computer-executable code. The hardware circuit may include conventional very-large-scale integrated circuits (VLSI) or gate arrays, as well as existing semiconductors or other discrete components such as logic chips and transistors; the hardware circuit may also include field-programmable gate arrays, programmable array logic, programmable logic devices, etc. Furthermore, those skilled in the art will understand that the above structure does not constitute a limitation on the display device provided in the embodiments of this disclosure. In other words, the display device provided in the embodiments of this disclosure may include more or fewer of the above components, or combine certain components, or have different component arrangements.
[0128] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0129] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations to the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.
Claims
1. A display panel, wherein, include: An array substrate includes: a first substrate, an electrode structure located on one side of the first substrate, and a first alignment layer located on the side of the electrode structure opposite to the first substrate; wherein the electrode structure includes: a pixel electrode layer and a common electrode layer; The opposing substrate includes: a second substrate, and a second alignment layer located on the side of the second substrate facing the array substrate; An alignment layer is located between the array substrate and the opposing substrate. The alignment layer includes: a liquid crystal layer, a first polymer layer located on the side of the liquid crystal layer facing the array substrate, and a second polymer layer located on the side of the liquid crystal layer facing the opposing substrate; wherein the first polymer layer and the second polymer layer are formed by irradiating reactive monomers mixed in the liquid crystal layer with ultraviolet light; the horizontal electric field formed by the pixel electrode layer and the common electrode layer is used to drive the liquid crystal layer to rotate.
2. The display panel as claimed in claim 1, wherein, The materials of the first alignment layer and the second alignment layer include photoisomeric polyimide.
3. The display panel as described in claim 2, wherein, The materials of the first alignment layer and the second alignment layer include:
4. The display panel as described in any one of claims 1-3, wherein, The pixel electrode layer includes: a plurality of pixel electrodes; each pixel electrode includes a first axis extending along a first direction and passing through the center of the pixel electrode. The pixel electrode includes: a plurality of slits arranged along the first direction; the slits include: a first sub-slit portion located on one side of the first axis, and a second sub-slit portion located on the other side of the first axis.
5. A display device, wherein, Includes the display panel as described in any one of claims 1-4.
6. A method for manufacturing a display panel, wherein, include: An array substrate having a first alignment layer and an opposing substrate having a second alignment layer are formed. Ultraviolet light is used to perform photo-alignment on the first alignment layer of the array substrate and the second alignment layer of the opposing substrate; Liquid crystal mixed with reactive monomers is injected between the array substrate and the opposing substrate, and the array substrate and the opposing substrate are then bonded together to form a display panel; The display panel is irradiated with ultraviolet light so that the reactive monomers form a first polymer layer on the surface of the first alignment layer facing the opposing substrate and a second polymer layer on the surface of the second alignment layer facing the array substrate.
7. The manufacturing method as described in claim 6, wherein, The method of aligning the first alignment layer of the array substrate and the second alignment layer of the opposing substrate using ultraviolet light includes: Ultraviolet light, along with an open mask, is used to align the first alignment layer of the array substrate and the second alignment layer of the opposing substrate.
8. The manufacturing method as described in claim 7, wherein, The method of aligning the first alignment layer of the array substrate and the second alignment layer of the opposing substrate using ultraviolet light includes: Ultraviolet light is used, specifically the 300nm–330nm ultraviolet polarized light band. The angle between the light irradiation angle and the acute angle formed by the first alignment layer is controlled to be within the range of 40°–60° for alignment, and the angle between the light irradiation angle and the acute angle formed by the second alignment layer is also controlled to be within the range of 40°–60° for alignment.
9. The manufacturing method according to any one of claims 6-8, wherein, The method of aligning the first alignment layer of the array substrate and the second alignment layer of the opposing substrate using ultraviolet light includes: The first and second rows of ultraviolet lamps were used for simultaneous exposure, with the exposure illuminance controlled at 50 mW / cm². 2 ~70mw / cm 2 The exposure speed is 100mm / s to 160mm / s, and the exposure energy is 30mJ to 50mJ. The first alignment layer of the array substrate and the second alignment layer of the opposing substrate are aligned.
10. The manufacturing method according to any one of claims 6-9, wherein, The step of irradiating the display panel with ultraviolet light to form a first polymer layer on the surface of the first alignment layer facing the opposing substrate and a second polymer layer on the surface of the second alignment layer facing the array substrate includes: Using 350nm~380nm and energy of 8J / cm 2 ~12J / cm 2 Unpolarized ultraviolet light is used, and the angle between the irradiation angle and the first substrate is controlled to be within the range of 80° to 100°, so that the reactive monomer forms a first polymer layer on the surface of the first alignment layer facing the opposing substrate, and a second polymer layer forms on the surface of the second alignment layer facing the array substrate.
11. The manufacturing method according to any one of claims 6-10, wherein, The step of irradiating the display panel with ultraviolet light includes: The array substrate controlling the display panel is located on the side of the opposing substrate facing the ultraviolet light source, irradiating the display panel.
12. The manufacturing method according to any one of claims 6-11, wherein, The process of injecting liquid crystal mixed with reactive monomers between the array substrate and the opposing substrate, and then bonding the array substrate and the opposing substrate together to form a display panel includes: A mixture is formed in which the concentration of the reactive monomer in the liquid crystal ranges from 1800 ppm to 2200 ppm; The mixture is injected between the array substrate and the opposing substrate, and the array substrate and the opposing substrate are then bonded together to form a display panel.
13. The manufacturing method according to any one of claims 6-12, wherein, The array substrate having a first alignment layer and the opposing substrate having a second alignment layer comprise: A photoisotropic polyimide film is coated on the surface of the array substrate as a first alignment layer, and a photoisotropic polyimide film is coated on the surface of the opposing substrate as a second alignment layer. The first alignment film layer and the second alignment film layer are first cured at a temperature of 70℃~90℃; The first alignment film and the second alignment film are cured a second time at a temperature of 220℃~250℃.
14. The manufacturing method according to any one of claims 6-13, wherein, The display panel includes: an ADS display panel or a VA display panel.