Display screen cover plate and coating method thereof

Abstract

This invention discloses a coating method for a display screen cover plate. Using an infrared cutoff glass cover plate as the coating substrate, a composite film layer is deposited on the outer surface of the infrared cutoff glass cover plate. This composite film layer simultaneously possesses visible light antireflection and infrared light cutoff functions. This coating method can simultaneously meet the requirements of visible light antireflection and infrared light cutoff using a relatively thin composite film layer. This invention also discloses a display screen cover plate prepared using the above-described coating method.

Description

Technical Field

[0001] This invention relates to cover plate coating technology, and in particular to a display screen cover plate and its coating method. Background Technology

[0002] Display cover plates are typically made of optical glass. The difference in refractive index between the glass and air causes surface reflection, resulting in severe glare and reduced contrast under strong light. Therefore, the industry commonly uses anti-reflective coatings (AR coatings) to optimize visual effects. However, in outdoor applications such as motorcycles and vehicles, the heat radiation from the sun's near-infrared rays can cause the cover plate to overheat. This can easily lead to the OCA optical adhesive bonding the cover plate to the display screen coming unglued, causing the cover plate to fall off. It can also affect the operational stability of the electronic components inside the display screen. Therefore, a composite film layer with both visible light anti-reflection and infrared light blocking functions is required.

[0003] However, in existing technologies, the composite film layer uses an aluminosilicate glass cover plate as the coating substrate. To simultaneously meet the requirements of visible light antireflection and infrared light cutoff, the total number of layers in this composite film layer needs to be at least ten or more, resulting in a large film thickness. A thicker composite film layer not only presents challenges in optical design and is prone to interference wavelength misalignment, affecting infrared cutoff accuracy, but also generates stray light and ghosting, further degrading display effects. It also generates significant deposition stress, making the film layer prone to cracking and detachment under outdoor temperature changes and vibration conditions, leading to insufficient reliability. Furthermore, due to the large film thickness, the coating time required for this composite film layer is long, resulting in low coating efficiency. Moreover, after prolonged operation, the temperature inside the coating chamber of the coating machine becomes too high. Since existing cover plates require full-surface coating, they cannot be clamped at the edges for loading and unloading; they can only be glued to the fixture. The excessively high chamber temperature easily causes the adhesive between the cover plate and the fixture to fail, leading to cover plate detachment and significantly reducing the coating yield. Summary of the Invention

[0004] To address the shortcomings of the prior art, this invention provides a display screen cover and its coating method, which can simultaneously meet the requirements of visible light anti-reflection and infrared light cutoff by using a composite film layer with a relatively small thickness.

[0005] The technical problem to be solved by the present invention is achieved through the following technical solution: A coating method for a display screen cover plate, using an infrared cut-off glass cover plate as the coating substrate, depositing a composite film layer on the outer surface of the infrared cut-off glass cover plate, wherein the composite film layer has both visible light anti-reflection and infrared light cut-off functions.

[0006] Furthermore, the composite film layer has a high light absorption rate or high reflectivity in the infrared band, and the infrared cut-off glass cover is an infrared absorbing glass or an infrared reflecting glass.

[0007] Furthermore, the composite film layer has high reflectivity in the infrared band, and the infrared cut-off glass cover is infrared absorbing glass.

[0008] Furthermore, the infrared cut-off glass cover is a phosphate optical glass containing copper oxide, and the mass percentage of copper oxide in the infrared cut-off glass cover is 0.5-2.5%.

[0009] Furthermore, the composite film is formed by alternating layers of multiple high-refractive-index films and multiple low-refractive-index films.

[0010] Furthermore, the step of depositing a composite film layer on the outer surface of the infrared cutoff glass cover is as follows: The inner surface of the infrared cut-off glass cover is bonded and fixed to a coating fixture. The coating fixture with the infrared cut-off glass cover plate bonded to it is fed into the coating chamber of the coating machine. The coating machine is used to sequentially deposit each layer of the composite film on the outer surface of the infrared cut-off glass cover. The coating fixture with the infrared cut-off glass cover plate bonded to it is removed from the coating chamber of the coating machine and unloaded. The infrared cutoff glass cover plate coated with the composite film is peeled off from the coating fixture.

[0011] Furthermore, the coating machine is a magnetron sputtering coating machine or a vacuum evaporation coating machine.

[0012] Furthermore, the infrared cutoff glass cover is not less than 6 inches, and the coating machine is a magnetron sputtering coating machine.

[0013] Furthermore, the infrared cutoff glass cover and the composite film have an average reflectance Rave≤1% in the visible light band of 400-700nm, an average transmittance Tave≤30% in the infrared light band of 800-1000nm, and a film thickness of less than 0.3 micrometers.

[0014] A display screen cover is prepared by the above-described coating method.

[0015] The present invention has the following beneficial effects: The coating method of the present invention uses an infrared cutoff glass cover as the coating substrate to replace the aluminosilicate glass cover of the prior art, and deposits a composite film layer with both visible light antireflection and infrared light cutoff functions on the outer surface of the infrared cutoff glass cover. By utilizing the synergistic infrared cutoff effect of the infrared cutoff glass cover and the composite film layer, the film thickness of the composite film layer is reduced. This not only reduces the optical design difficulty of the composite film layer to avoid interference wavelength misalignment, but also reduces the deposition stress of the composite film layer, making the film layer more stable and reliable under outdoor temperature change and vibration conditions. At the same time, due to the significant reduction in the film thickness of the composite film layer, the coating time of the coating machine is short and the coating efficiency is high. Moreover, the temperature inside the coating chamber of the coating machine is low, which can prevent the peelable adhesive between the infrared cutoff glass cover and the coating fixture from failing due to prolonged high temperature, thereby preventing the infrared cutoff glass cover from falling off during coating and improving the coating yield. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the stacked structure of the display cover plate provided by the present invention.

[0017] Figure 2 This is a schematic diagram of the stacked structure of another display cover provided by the present invention.

[0018] Figure 3 A flowchart illustrating the steps of the coating method for the display screen cover provided by the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, "multiple" means two or more, unless otherwise explicitly specified.

[0022] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," and "setting," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Example 1 like Figure 1 As shown, a coating method for a display screen cover plate uses an infrared cut-off glass cover plate 1 as the coating substrate, and a composite film layer 2 is deposited on the outer surface of the infrared cut-off glass cover plate 1. The composite film layer 2 has both visible light anti-reflection and infrared light cut-off functions.

[0024] The coating method of the present invention uses an infrared cutoff glass cover plate 1 as the coating substrate to replace the aluminosilicate glass cover plate of the prior art. A composite film layer 2 with visible light antireflection and infrared light cutoff functions is deposited on the outer surface of the infrared cutoff glass cover plate 1. By utilizing the synergistic infrared cutoff effect of the infrared cutoff glass cover plate 1 and the composite film layer 2, the film thickness of the composite film layer 2 is reduced. This not only reduces the optical design difficulty of the composite film layer 2 to avoid interference wavelength misalignment, but also reduces the deposition stress of the composite film layer 2, making the film layer more stable and reliable under outdoor temperature change and vibration conditions.

[0025] The infrared cut-off glass cover 1 has an inner surface and an outer surface arranged opposite each other along its thickness direction. The inner surface is the side facing the display screen during use, and the outer surface is the side facing the user or air during use. During assembly, the inner surface of the infrared cut-off glass cover 1 needs to be bonded to the display screen or touch screen with OCA optical adhesive.

[0026] The composite film layer 2 has a high light absorption rate or high reflectivity in the infrared band, and the infrared cut-off glass cover plate 1 is an infrared absorbing glass or an infrared reflecting glass.

[0027] In the first example, the composite film layer 2 has high reflectivity in the infrared band, and the infrared cut-off glass cover 1 is infrared reflective glass; in the second example, the composite film layer 2 has high absorbivity in the infrared band, and the infrared cut-off glass cover 1 is infrared absorbing glass; in the third example, the composite film layer 2 has high reflectivity in the infrared band, and the infrared cut-off glass cover 1 is infrared absorbing glass; in the fourth example, the composite film layer 2 has high absorbivity in the infrared band, and the infrared cut-off glass cover 1 is infrared reflective glass.

[0028] Given that the composite film layer 2 has high reflectivity in the infrared band and the infrared cut-off glass cover plate 1 is a total internal reflection scheme for infrared reflective glass, infrared light can be reflected multiple times at the interface between the infrared reflective glass and the composite film layer 2. After superimposing and interfering with visible light, stray light, ghosting, and glare will be generated, which seriously interfere with the visual clarity of the motorcycle display screen under strong light. In order to avoid the interference wavelength misalignment between the infrared reflective glass and the composite film layer 2, the optical parameters of the glass and the film layer must be strictly matched, and even matched with the optical parameters of the antireflective film 3. The design is difficult and has a low tolerance for error.

[0029] For the composite film layer 2, which has a high absorption rate in the infrared band, and the infrared cut-off glass cover plate 1, which is a full absorption scheme of infrared absorbing glass, almost all infrared light is absorbed by the composite film layer 2 and the infrared absorbing glass. Its infrared radiation energy is converted into heat energy. Under the summer sun, the temperature of the cover plate will rise sharply, causing the OCA optical adhesive to fail and the display screen to thermally run away.

[0030] For the composite film layer 2, which has a high light absorption rate in the infrared band, and the infrared cut-off glass cover plate 1, which is an infrared reflective glass with a first absorption and then reflection scheme, the infrared light is first absorbed by the composite film layer 2, and part of its infrared radiation energy is converted into heat energy. The other part is reflected by the infrared reflective glass and then absorbed by the composite film layer 2 again. This part of the infrared radiation energy is also converted into heat energy, which will also cause the temperature of the composite film layer 2 to be too high. As a result, the light-absorbing material of the composite film layer 2 will degrade due to high temperature, the bonding force between the film layer and the glass will decrease, and long-term outdoor exposure will easily cause the film layer to peel off and the absorption performance to deteriorate. Moreover, the composite film layer 2 is a thin film structure with extremely low heat capacity. The absorbed heat will be quickly conducted to the infrared reflective glass on its inner surface, causing the infrared reflective glass to heat up as well. Ultimately, the OCA optical adhesive will fail and the display screen will experience thermal runaway.

[0031] For the composite film layer 2, which has high reflectivity in the infrared band, and the infrared cut-off glass cover plate 1, which is an infrared absorbing glass with a first-reflection-then-absorption scheme, the portion of infrared light passing through the composite film layer 2 will be absorbed by the infrared absorbing glass, cutting off the reflection circuit between the composite film layer 2 and the infrared absorbing glass. This completely eliminates the optical crosstalk of the total internal reflection scheme, and the reflection band of the composite film layer 2 and the absorption band of the infrared absorbing glass do not need to be precisely interfered and matched. At the same time, the composite film layer 2 first blocks and reflects 60% to 70% of the infrared light to the outside, and only a small amount of residual infrared light is absorbed by the infrared absorbing glass. This greatly reduces the heating effect of the infrared absorbing glass, fundamentally solving the heat accumulation problem of the total absorption scheme and the first-absorption-then-reflection scheme.

[0032] Therefore, the present invention preferably uses the composite film layer 2 which has high reflectivity in the infrared light band, and the infrared cut-off glass cover plate 1 is an infrared absorbing glass with a first reflection and then absorption scheme.

[0033] When the infrared cut-off glass cover 1 is an infrared absorbing glass, the infrared cut-off glass cover 1 is preferably a phosphate optical glass containing copper oxide, and the mass percentage of copper oxide in the infrared cut-off glass cover 1 is 0.5-2.5%.

[0034] The copper oxide in the phosphate optical glass releases copper ions, which are the core functional groups that enable the infrared absorbing glass to absorb infrared light. The main components of the phosphate optical glass are phosphorus pentoxide and modified phosphate. The phosphorus pentoxide forms the glass network structure of the phosphate optical glass through "PO4 tetrahedra," and its mass percentage in the infrared cutoff glass cover plate 1 is 50-55%. The modified phosphate includes at least one of barium metaphosphate, aluminum metaphosphate, and sodium metaphosphate to enhance the mechanical strength, chemical stability, and surface wettability of the phosphate optical glass, and its mass percentage in the infrared cutoff glass cover plate 1 is 39.5-49.5%.

[0035] The composite film layer 2 is formed by alternating layers of multiple high-refractive-index films and multiple low-refractive-index films. The number of high-refractive-index and low-refractive-index films is between 3 and 6, depending on the required visible light anti-reflection and infrared cutoff effects, as well as the specific refractive indices of the high-refractive-index and low-refractive-index materials.

[0036] Preferably, the high refractive index film is a niobium pentoxide film, and the low refractive index film is a silicon dioxide film. Both the niobium pentoxide film and the silicon dioxide film have good lattice compatibility with the phosphate optical glass, and can be more stably bonded and attached to the surface of the phosphate optical glass.

[0037] The thickness of each niobium pentoxide film layer is between 14-26 nm, and the thickness of each silicon dioxide film layer is between 24-31 nm.

[0038] More preferably, the niobium pentoxide film layer is located on the inner surface of the composite film layer 2 and is combined with the infrared cutoff glass cover plate 1 to improve the bonding force between the composite film layer 2 and the phosphate optical glass. The silicon dioxide film layer is located on the outer surface of the composite film layer 2 to optimize the interface matching between the composite film layer 2 and the outside air.

[0039] In this embodiment, as Figure 2 As shown, the composite film layer 2 is formed by alternating layers of three niobium pentoxide films and four silicon dioxide films, for a total of seven layers. Specifically, it includes a first silicon dioxide film layer, a first niobium pentoxide film layer, a second silicon dioxide film layer, a second niobium pentoxide film layer, a third silicon dioxide film layer, a third niobium pentoxide film layer, and a fourth silicon dioxide layer, which are sequentially stacked on the outer surface of the infrared cutoff glass cover plate 1. The thicknesses of each film layer are 20nm, 13nm, 35nm, 53nm, 10nm, 39nm, and 89nm, respectively, with a total thickness of approximately 250nm. The thickness error of each film layer can be controlled within ±5.

[0040] The infrared cutoff glass cover plate 1 and the composite film layer 2 have an average reflectance Rave≤1% in the visible light band of 400-700nm and an average transmittance Tave≤30% in the infrared light band of 800-1000nm. The total film thickness of the composite film layer 2 is less than 0.3 micrometers.

[0041] In contrast, if the composite film 2 is deposited on the aluminosilicate glass cover using existing technology, to achieve the same average reflectance Rave≤1% in the visible light band (400-700nm) and average transmittance Tave≤30% in the infrared band (800-1000nm), the film thickness of the composite film 2 would need to be approximately 1.5 micrometers. Therefore, the present invention reduces the film thickness of the composite film 2 by approximately 80%.

[0042] Specifically, such as Figure 3 As shown, the steps for sequentially depositing the composite film layer 2 on the outer surface of the infrared cutoff glass cover plate 1 are as follows: Step S1: Adhere and fix the inner surface of the infrared cut-off glass cover plate 1 to a coating fixture; Step S2: The coating fixture with the infrared cut-off glass cover plate 1 bonded and fixed is fed into the coating chamber of the coating machine; Step S3: The coating machine is used to sequentially coat each layer of the composite film layer 2 on the outer surface of the infrared cut-off glass cover plate 1. Step S4: Remove the coating fixture with the infrared cut-off glass cover plate 1 bonded and fixed to it from the coating chamber of the coating machine and unload it; Step S5: Peel the infrared cut-off glass cover plate 1 coated with the composite film layer 2 from the coating fixture.

[0043] The coating fixture has an adhesive surface, and the inner surface of the infrared cutoff glass cover 1 is bonded to the adhesive surface of the coating fixture with peelable adhesive. Since the entire outer surface of the infrared cutoff glass cover 1 needs to be coated, it is impossible to use a clamp to hold and fix the edge of the infrared cutoff glass cover 1 to move it up and down. Therefore, the coating fixture is used to bond and fix the inner surface of the infrared cutoff glass cover 1 to move it up and down.

[0044] In the prior art, due to the large thickness of the composite film layer 2, the coating time of the coating machine is long and the coating efficiency is low. Moreover, when the coating machine is working for a long time, the temperature inside the coating chamber is too high. The peelable adhesive between the aluminosilicate glass cover and the coating fixture is prone to failure under long-term high temperature, which causes the aluminosilicate glass cover to fall off during coating and affects the coating yield.

[0045] In this embodiment, because the infrared cutoff glass cover plate 1 is used instead of the aluminosilicate glass cover plate of the prior art, the film thickness of the composite film layer 2 is greatly reduced. The coating time of the coating machine is short and the coating efficiency is high. Moreover, the temperature inside the coating chamber of the coating machine is low, which can prevent the peelable adhesive between the infrared cutoff glass cover plate 1 and the coating fixture from failing due to prolonged high temperature. This prevents the infrared cutoff glass cover plate 1 from falling off during coating and improves the coating yield.

[0046] The coating machine is a magnetron sputtering coating machine or a vacuum evaporation coating machine.

[0047] When the infrared cutoff glass cover plate 1 is not less than 6 inches, the efficiency of coating the infrared cutoff glass cover plate 1 using the vacuum evaporation coating machine is low and the production capacity is small. Therefore, in this case, the coating machine is preferably a magnetron sputtering coating machine.

[0048] Example 2 like Figure 1As shown, a display screen cover includes an infrared cut-off glass cover 1 and a composite film layer 2. The composite film layer 2 is deposited on the outer surface of the infrared cut-off glass cover 1. The infrared cut-off glass cover 1 and the composite film layer 2 have an average reflectance Rave≤1% in the visible light band of 400-700nm and an average transmittance Tave≤30% in the infrared light band of 800-1000nm. The film thickness of the composite film layer 2 is less than 0.3 micrometers.

[0049] The display screen cover is prepared by the above-described coating method. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention and not to limit them. Although the embodiments of the present invention have been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the embodiments of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coating method for a display screen cover, characterized in that, Using an infrared cutoff glass cover as the coating substrate, a composite film layer is deposited on the outer surface of the infrared cutoff glass cover. The composite film layer has both visible light anti-reflection and infrared light cutoff functions.

2. The coating method according to claim 1, characterized in that, The composite film layer has a high light absorption rate or high reflectivity in the infrared band, and the infrared cut-off glass cover is an infrared absorbing glass or an infrared reflecting glass.

3. The coating method according to claim 1, characterized in that, The composite film has high reflectivity in the infrared band, and the infrared cut-off glass cover is infrared absorbing glass.

4. The coating method according to claim 1 or 3, characterized in that, The infrared cutoff glass cover is a phosphate optical glass containing copper oxide, and the mass percentage of copper oxide in the infrared cutoff glass cover is 0.5-2.5%.

5. The coating method according to claim 1, characterized in that, The composite film is formed by alternating layers of multiple high-refractive-index films and multiple low-refractive-index films.

6. The coating method according to claim 1, characterized in that, The steps for depositing a composite film layer on the outer surface of the infrared cutoff glass cover are as follows: The inner surface of the infrared cut-off glass cover is bonded and fixed to a coating fixture. The coating fixture with the infrared cut-off glass cover plate bonded to it is fed into the coating chamber of the coating machine. The coating machine is used to sequentially deposit each layer of the composite film on the outer surface of the infrared cut-off glass cover. The coating fixture with the infrared cut-off glass cover plate bonded to it is removed from the coating chamber of the coating machine and unloaded. The infrared cutoff glass cover plate coated with the composite film is peeled off from the coating fixture.

7. The coating method according to claim 5, characterized in that, The coating machine is a magnetron sputtering coating machine or a vacuum evaporation coating machine.

8. The coating method according to claim 5, characterized in that, The infrared cutoff glass cover is not less than 6 inches, and the coating machine is a magnetron sputtering coating machine.

9. The coating method according to claim 1, characterized in that, The infrared cutoff glass cover and composite film have an average reflectance Rave≤1% in the visible light band of 400-700nm and an average transmittance Tave≤30% in the infrared light band of 800-1000nm. The thickness of the composite film is less than 0.3 micrometers.

10. A display screen cover, characterized in that, It is prepared by the coating method described in claim 1.

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