Display panel and manufacturing method thereof

Abstract

This invention relates to the field of display panel technology, and discloses a display panel and its preparation method, comprising a display panel substrate, a first ITO film, and a second ITO film; the first ITO film is disposed on the upper surface of the display panel substrate, and the second ITO film is disposed on the lower surface of the display panel substrate; the material and thickness of the first and second ITO films are adaptively adjusted according to the type of display panel; the absolute value of the difference between the coefficient of thermal expansion and contraction of the first and second ITO films and the coefficient of thermal expansion and contraction of the display panel substrate is ≤5×10⁻⁶ / ℃. This invention improves the compatibility of the ITO film with the display panel, avoids film cracking and peeling, optimizes display effect and mechanical properties, has a controllable preparation process, strong compatibility, is suitable for large-scale mass production, and can be widely used in the production of various types of display panels.

Description

Technical Field

[0001] This invention relates to the field of display panel technology, specifically to a display panel and its manufacturing method. Background Technology

[0002] As the core display component of electronic devices, display panels are widely used in various scenarios such as mobile phones, computers, televisions, and automotive displays. Their display effect, mechanical performance, and stability directly determine the user experience of electronic devices. ITO (Indium Tin Oxide) film, as a transparent conductive material with both high light transmittance and high conductivity, is a core component of display panel electrodes and touch layers, and is widely used in various display panels such as TFT LCD displays and OLED displays.

[0003] In existing technologies, display panels typically have an ITO film on only a single surface, or although an ITO film may be applied to both the upper and lower surfaces, the material and thickness of the ITO film are not adaptively adjusted according to the type of display panel. This results in poor compatibility between the ITO film and the display panel, failing to fully leverage the display panel's advantages. Furthermore, existing technologies do not specifically control the temperature expansion and contraction coefficient of the ITO film, leading to a significant difference in expansion coefficients between the ITO film and the display panel substrate. During the display panel's manufacturing process (such as annealing and deposition) and usage (such as changes in ambient temperature), inconsistent thermal expansion and contraction can generate internal stress, causing the ITO film to crack and peel off, thus affecting the display panel's lifespan and display stability.

[0004] Furthermore, for OLED display panels, existing ITO films are mostly transparent materials, which cannot meet the color adaptation requirements of some special display scenarios; for TFT liquid crystal display panels, the light transmittance and conductivity of ITO films are not well controlled, which can easily lead to problems such as blurry display and unresponsive touch; at the same time, the existing ITO film preparation methods have defects such as uneven film deposition and weak adhesion to the substrate, which further affect the overall performance of the display panel.

[0005] To address the aforementioned technical issues, there is an urgent need to design an ITO thin film-based display panel and its fabrication method that is highly adaptable, stable, has a long service life, and can meet the requirements of different types of display panels. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for improving panel strength, temperature and electrical stability, solving problems such as poor compatibility between ITO films and display panels, film cracking and peeling due to mismatched expansion coefficients, poor display effects and imperfect manufacturing processes in existing technologies.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a display panel, comprising a display panel substrate, a first ITO film, and a second ITO film; the first ITO film is disposed on the upper surface of the display panel substrate, and the second ITO film is disposed on the lower surface of the display panel substrate; the materials and thicknesses of the first and second ITO films are adaptively adjusted according to the type of the display panel; the absolute value of the difference between the coefficients of thermal expansion and contraction of the first and second ITO films and the coefficient of thermal expansion and contraction of the display panel substrate is ≤5×10⁻ 6 / ℃.

[0008] Preferably, when the display panel is a TFT liquid crystal display panel, both the first ITO film and the second ITO film are transparent ITO films, and the visible light transmittance of the transparent ITO film is ≥85%, and the sheet resistance is ≤10Ω / □.

[0009] Preferably, when the display panel is an OLED display panel, the second ITO film is an ITO film of any color, and the first ITO film is a transparent ITO film; the visible light transmittance of the transparent ITO film is ≥88%, and the color uniformity deviation of the colored ITO film is ≤5%.

[0010] Preferably, the thickness of the first ITO film and the second ITO film is 50-500 nm; when the display panel is a rigid display panel, the thickness of the ITO film is 200-500 nm; when the display panel is a flexible display panel, the thickness of the ITO film is 50-200 nm.

[0011] Preferably, when the display panel substrate is a glass substrate, the coefficient of thermal expansion and contraction of the ITO film is 3.0 × 10⁻⁻⁻⁶. 6 -8.0×10⁻ 6 / ℃; When the display panel substrate is a flexible polymer substrate, the coefficient of thermal expansion and contraction of the ITO film is 7.0×10⁻ 6 -12.0×10⁻ 6 / ℃.

[0012] Preferably, the ITO thin film is made of an indium tin oxide doped system, with a doping ratio of 5%-10% tin oxide and 90%-95% indium oxide; the colored ITO thin film is achieved by doping the indium tin oxide system with coloring elements, which are one or more of titanium, zirconium, and cerium, with a doping amount of 0.1%-2%.

[0013] Preferably, a transition layer is provided between the first ITO film and the display panel substrate, and between the second ITO film and the display panel substrate. The thickness of the transition layer is 10-50 nm, and the material is SiO2 or Al2O3.

[0014] A method for manufacturing a display panel, comprising the following steps:

[0015] S1. Pre-treat the display panel substrate to remove impurities, oil, and oxide layers from the surface of the substrate, resulting in a clean substrate;

[0016] S2. Determine the material and thickness of the first ITO film and the second ITO film according to the type of display panel, and adjust the temperature expansion and contraction coefficient of the ITO film to match the expansion coefficient of the display panel substrate.

[0017] S3. A physical vapor deposition process is used to deposit a first ITO film on the upper surface of a clean substrate and a second ITO film on the lower surface. The deposition temperature is controlled at 100-200℃ during the deposition process.

[0018] S4. Anneal the deposited first ITO film and second ITO film at a temperature of 250-350℃ for 30-60 minutes to obtain the substrate modified with ITO film.

[0019] Preferably, the physical vapor deposition process in step S3 is magnetron sputtering or electron beam evaporation. When using magnetron sputtering, the sputtering power is 100-300W, the sputtering pressure is 0.1-0.5Pa, and the sputtering gas is a mixture of argon and oxygen with a volume ratio of argon to oxygen of 10:1-5:1.

[0020] Preferably, the pretreatment in step S1 includes two steps: ultrasonic cleaning and plasma cleaning; the ultrasonic cleaning uses a mixed solution of ethanol and deionized water, and the ultrasonic time is 15-30 min; the plasma cleaning power is 50-100 W, and the cleaning time is 5-10 min.

[0021] The present invention has the following beneficial effects:

[0022] (1) The method for improving the strength, temperature and electrical stability of the panel is to set ITO film on both the upper and lower surfaces of the display panel substrate, and to adaptively adjust the material and thickness of the ITO film according to the type of display panel (TFT liquid crystal, OLED), thereby improving the compatibility between the ITO film and the display panel and giving full play to the display advantages of different types of display panels. TFT liquid crystal display panels use transparent ITO film to ensure light transmittance and conductivity; OLED display panels use a combination of transparent and colored ITO film to meet the display effect and color compatibility requirements.

[0023] (2) The method for improving the strength, temperature and electrical stability of the panel is to strictly control the temperature expansion and contraction coefficient of the ITO film, so that the difference between the expansion coefficient of the ITO film and the expansion coefficient of the display panel substrate is controlled within a reasonable range. This effectively avoids the internal stress caused by inconsistent thermal expansion and contraction, reduces the cracking and peeling of the ITO film, and significantly improves the stability and service life of the display panel.

[0024] (3) The method for improving the strength, temperature and electrical stability of the panel further improves the display effect of the display panel by optimizing the material (doping ratio, coloring elements) and thickness of the ITO film. The transparent ITO film ensures high light transmittance, the colored ITO film achieves color matching, and the reasonable thickness design takes into account both mechanical performance and display / conductivity performance. At the same time, the transition layer is set to enhance the bonding force between the ITO film and the substrate, further improving the product stability. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] A display panel includes a display panel substrate, a first ITO film, and a second ITO film. The first ITO film is disposed on the upper surface of the display panel substrate, and the second ITO film is disposed on the lower surface of the display panel substrate. The materials and thicknesses of the first and second ITO films are adaptively adjusted according to the type of the display panel. The absolute value of the difference between the coefficients of thermal expansion and contraction of the first and second ITO films and the coefficient of thermal expansion and contraction of the display panel substrate is ≤5×10⁻. 6 / ℃.

[0028] In this embodiment, when the display panel is a TFT liquid crystal display panel, both the first ITO film and the second ITO film are transparent ITO films. The visible light transmittance of the transparent ITO film is ≥85%, and the sheet resistance is ≤10Ω / □. In this technical solution, the TFT liquid crystal display panel has high requirements for the light transmittance and conductivity of the ITO film. The transparent ITO film can ensure the normal transmission of light, meeting the light transmittance requirements of the liquid crystal display. At the same time, the low sheet resistance can ensure the conductivity of the electrodes and avoid problems such as display blurring and touch delay.

[0029] In this embodiment, when the display panel is an OLED display panel, the second ITO film is an ITO film of any color, and the first ITO film is a transparent ITO film; the visible light transmittance of the transparent ITO film is ≥88%, and the color uniformity deviation of the colored ITO film is ≤5%. The light-emitting layer of the OLED display panel itself has light-emitting capability, and the colored ITO film on the lower surface can be adapted to different colors according to display requirements, improving the appearance diversity and special display effects of the display panel. At the same time, the transparent ITO film can ensure that the light from the OLED light-emitting layer is emitted smoothly, and the high transmittance and uniform color distribution can further improve the display quality of the display panel.

[0030] In this embodiment, the thickness of the first ITO film and the second ITO film is 50-500 nm; when the display panel is a rigid display panel, the thickness of the ITO film is 200-500 nm; when the display panel is a flexible display panel, the thickness of the ITO film is 50-200 nm. Rigid display panels (such as glass-based display panels) require high mechanical strength, and a thicker ITO film can improve their mechanical properties and conductivity; flexible display panels (such as polymer-based display panels) need to have good bending performance, and a thinner ITO film can reduce internal stress during bending, prevent film cracking, and ensure their light transmittance and conductivity.

[0031] In this embodiment, when the display panel substrate is a glass substrate, the coefficient of thermal expansion and contraction of the ITO film is 3.0 × 10⁻⁻⁻⁶. 6 -8.0×10⁻ 6 / ℃; When the display panel substrate is a flexible polymer substrate, the coefficient of thermal expansion and contraction of the ITO film is 7.0×10⁻ 6 -12.0×10⁻ 6 / ℃. By precisely matching the expansion coefficients of the ITO film and the substrate, the internal stress generated during thermal expansion and contraction can be effectively reduced, preventing the ITO film from cracking and peeling off, and improving the stability and lifespan of the display panel; the expansion coefficients of different substrates vary greatly, and the expansion coefficient of the ITO film can be adjusted in a targeted manner to further improve compatibility.

[0032] In this embodiment, the ITO thin film is made of an indium tin oxide (ITO) doped system, with a doping ratio of 5%–10% tin oxide and 90%–95% indium oxide. The colored ITO thin film is achieved by doping the ITO system with coloring elements, which are one or more of titanium, zirconium, and cerium, with a doping amount of 0.1%–2%. Tin oxide doping effectively improves the conductivity of the ITO thin film, while indium oxide ensures the film's light transmittance. A reasonable doping ratio achieves a balance between light transmittance and conductivity. The doping of coloring elements allows for color control of the ITO thin film, and by keeping the doping amount within a reasonable range, it avoids affecting the light transmittance and conductivity of the ITO thin film.

[0033] In this embodiment, transition layers are provided between the first ITO film and the display panel substrate, and between the second ITO film and the display panel substrate. The thickness of the transition layers is 10-50 nm, and the material is SiO2 or Al2O3. The transition layers can effectively improve the adhesion between the ITO film and the display panel substrate, prevent the ITO film from falling off, and at the same time reduce the impact of substrate surface defects on the deposition quality of the ITO film, thereby improving the uniformity and stability of the ITO film.

[0034] Example 2

[0035] A method for manufacturing a display panel lamp, used to manufacture a display panel according to any one of claims 1-7, comprising the following steps:

[0036] S1. Pre-treat the display panel substrate to remove impurities, oil, and oxide layers from the substrate surface, resulting in a clean substrate. Pre-treatment can improve the cleanliness and activity of the substrate surface, providing a good base for subsequent ITO film deposition and avoiding impurities, oil, etc., from affecting the adhesion between the ITO film and the substrate and the deposition quality of the film.

[0037] S2. Based on the type of display panel, determine the material and thickness of the first ITO film and the second ITO film, and adjust the coefficient of thermal expansion and contraction of the ITO film to match the coefficient of thermal expansion of the display panel substrate; through targeted adjustments, ensure the compatibility of the ITO film with the display panel and avoid various problems caused by mismatch in coefficient of thermal expansion.

[0038] S3. A physical vapor deposition process is used to deposit a first ITO film on the upper surface of a clean substrate and a second ITO film on the lower surface. The deposition temperature is controlled at 100-200℃ during the deposition process. Physical vapor deposition can achieve uniform deposition of ITO film. By controlling the reasonable deposition temperature, damage to the substrate caused by high temperature can be avoided. At the same time, the crystallinity of ITO film and its adhesion to the substrate are improved.

[0039] S4. Anneal the deposited first and second ITO films at a temperature of 250-350℃ for 30-60 minutes to obtain the substrate modified with ITO film. Annealing can eliminate the internal stress generated during the deposition of ITO film, improve the crystallinity and stability of the film, and further enhance the bonding force between the ITO film and the substrate, thus preventing the film from cracking and falling off.

[0040] In this embodiment, the physical vapor deposition process in step S3 is either magnetron sputtering or electron beam evaporation. When using magnetron sputtering, the sputtering power is 100-300W, the sputtering pressure is 0.1-0.5Pa, and the sputtering gas is a mixture of argon and oxygen, with a volume ratio of argon to oxygen of 10:1-5:1. Magnetron sputtering has advantages such as fast deposition rate, good film uniformity, and strong adhesion to the substrate, making it suitable for large-scale mass production. Electron beam evaporation can achieve precise deposition of ultra-thin ITO films, making it suitable for applications with high requirements for film thickness, such as flexible display panels. Reasonable control of sputtering parameters can ensure the uniformity and precise thickness of the ITO film, while improving the film's light transmittance and conductivity.

[0041] In this embodiment, the pretreatment in step S1 includes two steps: ultrasonic cleaning and plasma cleaning. Ultrasonic cleaning uses a mixed solution of ethanol and deionized water, with an ultrasonic time of 15-30 minutes. Plasma cleaning has a power of 50-100W and a cleaning time of 5-10 minutes. Ultrasonic cleaning effectively removes oil and soluble impurities from the substrate surface, while plasma cleaning removes the oxide layer and residual impurities from the substrate surface. Simultaneously, it enhances the activity of the substrate surface, further strengthening the adhesion between the ITO film and the substrate, and preventing subsequent film peeling, cracking, and other problems.

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the phrase "comprising an element defined as..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A display panel, characterized in that, It includes a display panel substrate, a first ITO film, and a second ITO film; the first ITO film is disposed on the upper surface of the display panel substrate, and the second ITO film is disposed on the lower surface of the display panel substrate; the material and thickness of the first ITO film and the second ITO film are adaptively adjusted according to the type of display panel; The absolute value of the difference between the coefficients of thermal expansion and contraction of the first and second ITO films and the coefficient of thermal expansion and contraction of the display panel substrate is ≤5×10⁻ 6 / ℃.

2. The display panel according to claim 1, characterized in that: When the display panel is a TFT liquid crystal display panel, both the first ITO film and the second ITO film are transparent ITO films, with a visible light transmittance of ≥85% and a sheet resistance of ≤10Ω / □.

3. The display panel according to claim 1, characterized in that: When the display panel is an OLED display panel, the second ITO film is an ITO film of any color, and the first ITO film is a transparent ITO film; the visible light transmittance of the transparent ITO film is ≥88%, and the color uniformity deviation of the colored ITO film is ≤5%.

4. The display panel according to claim 1, characterized in that: The thickness of the first ITO film and the second ITO film is 50-500nm; when the display panel is a rigid display panel, the thickness of the ITO film is 200-500nm; when the display panel is a flexible display panel, the thickness of the ITO film is 50-200nm.

5. The display panel according to claim 1, characterized in that: When the display panel substrate is a glass substrate, the coefficient of thermal expansion and contraction of the ITO film is 3.0 × 10⁻⁻⁻⁶. 6 -8.0×10⁻ 6 / ℃; When the display panel substrate is a flexible polymer substrate, the coefficient of thermal expansion and contraction of the ITO film is 7.0×10⁻ 6 -12.0×10⁻ 6 / ℃.

6. The display panel according to claim 1, characterized in that: The ITO thin film is made of an indium tin oxide doped system, with a doping ratio of 5%-10% tin oxide and 90%-95% indium oxide; the colored ITO thin film is achieved by doping the indium tin oxide system with coloring elements, which are one or more of titanium, zirconium, and cerium, with a doping amount of 0.1%-2%.

7. The display panel according to claim 1, characterized in that: A transition layer is provided between the first ITO film and the display panel substrate, and between the second ITO film and the display panel substrate. The thickness of the transition layer is 10-50nm, and the material is SiO2 or Al2O3.

8. A method for manufacturing a display panel, characterized in that: The method for preparing a display panel according to any one of claims 1-7 includes the following steps: S1. Pre-treat the display panel substrate to remove impurities, oil, and oxide layers from the surface of the substrate, resulting in a clean substrate; S2. Determine the material and thickness of the first ITO film and the second ITO film according to the type of display panel, and adjust the temperature expansion and contraction coefficient of the ITO film to match the expansion coefficient of the display panel substrate. S3. A physical vapor deposition process is used to deposit a first ITO film on the upper surface of a clean substrate and a second ITO film on the lower surface. The deposition temperature is controlled at 100-200℃ during the deposition process. S4. Anneal the deposited first ITO film and second ITO film at a temperature of 250-350℃ for 30-60 minutes to obtain the substrate modified with ITO film.

9. The preparation method according to claim 8, characterized in that: In step S3, the physical vapor deposition process is either magnetron sputtering or electron beam evaporation. When using magnetron sputtering, the sputtering power is 100-300W, the sputtering pressure is 0.1-0.5Pa, and the sputtering gas is a mixture of argon and oxygen with a volume ratio of argon to oxygen of 10:1-5:

1.

10. The preparation method according to claim 8, characterized in that: The pretreatment in step S1 includes two steps: ultrasonic cleaning and plasma cleaning. Ultrasonic cleaning uses a mixed solution of ethanol and deionized water, and the ultrasonic time is 15-30 min. The plasma cleaning power is 50-100 W, and the cleaning time is 5-10 min.