High bandwidth wet low e film

Abstract

The utility model discloses a kind of wet-process low reflection film of large bandwidth, including substrate layer, hard coating, high refractive index coating, bandwidth widening layer and low refractive index coating which are sequentially laminated;Wherein, the refractive index of high refractive index coating is 1.65-1.75, the refractive index of bandwidth widening layer is 2.0-2.5, the refractive index of low refractive index coating is 1.30-1.35.The utility model greatly improves the working bandwidth size of film by setting bandwidth widening layer between high refractive index coating and low refractive index coating, and using metal oxide with high refractive index to prepare bandwidth widening layer, reduces the average reflectivity and Y value (visual reflectivity) of film.

Description

Technical Field

[0001] This invention belongs to the field of optical thin film technology, specifically relating to a large-bandwidth wet-process low-reflection thin film. Background Technology

[0002] The high reflectivity of consumer electronics significantly impacts the user's visual experience, especially in bright sunlight where screen glare can interfere with reading content. To address this issue, a low-reflectivity film prepared using wet coating technology employs a multi-layered functional structure design to form a nanoscale coating on a transparent substrate. This not only controls reflectivity within the optically optimal range but also simultaneously improves light transmittance and color performance. This technology utilizes composite materials such as organic polymers and oxides, maintaining excellent optical performance while providing scratch-resistant protection for the screen.

[0003] With the optimization of coating processes, wet production has achieved precise thickness control, solving the early problem of uniformity in nano-coatings and significantly improving reflectivity fluctuations and color differences. This technology, which combines cost advantages with mass production stability, is widely used in mobile terminals such as smartphones and tablets. Its low-reflection effect allows the screen to maintain clear display even under strong outdoor light, and the increased brightness due to improved light transmittance can also alleviate eye fatigue. Through material innovation and process upgrades, wet-process low-reflection films are continuously driving the iterative upgrade of consumer electronics display quality.

[0004] Existing wet-process low-reflection film technologies require two or three layers to achieve the desired low-reflection effect. Typically, the reflection curve of a two-layer structure is "V"-shaped, while the reflection curve of a three-layer structure is "W"-shaped. Although the working bandwidth of a three-layer low-reflection film is larger and the reflectivity is lower than that of a two-layer structure, it still does not meet the needs of some specific application scenarios. Therefore, it is necessary to design a wet-process low-reflection film with a large bandwidth and extremely low reflectivity to meet market demands.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this utility model and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0006] The purpose of this invention is to provide a wet-process low-reflection film with a large bandwidth, which has a large operating bandwidth and ultra-low reflectivity.

[0007] To achieve the above objectives, the technical solution provided by a specific embodiment of this utility model is as follows:

[0008] A wide-bandwidth wet-process low-reflection thin film includes a substrate layer, a hardening coating, a high-refractive-index coating, a bandwidth-enhancing layer, and a low-refractive-index coating stacked sequentially.

[0009] The high refractive index coating has a refractive index of 1.65-1.75, the bandwidth widening layer has a refractive index of 2.0-2.5, and the low refractive index coating has a refractive index of 1.30-1.35.

[0010] In one or more embodiments of this utility model, the bandwidth broadening layer is a niobium pentoxide coating, a titanium dioxide coating, or a zirconium dioxide coating.

[0011] In one or more embodiments of this utility model, the thickness of the bandwidth broadening layer is 2nm-8nm.

[0012] In one or more embodiments of this utility model, the high refractive index coating is a polyurethane resin layer with a thickness of 120nm-150nm.

[0013] In one or more embodiments of this utility model, the low refractive index coating is an acrylic resin layer with a thickness of 95nm-110nm.

[0014] In one or more embodiments of this invention, the refractive index of the hardening coating is 1.50-1.55.

[0015] In one or more embodiments of this utility model, the hardening coating is an acrylic layer with a thickness of 3μm-5μm.

[0016] In one or more embodiments of this utility model, the substrate layer is a TAC layer.

[0017] Compared with the prior art, this invention greatly improves the working bandwidth of the film and reduces the average reflectance and Y value (visual reflectance) of the film by setting a bandwidth broadening layer between the high refractive index coating and the low refractive index coating and using metal oxides with high refractive index (niobium pentoxide, titanium dioxide, zirconium dioxide) to prepare the bandwidth broadening layer. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a large-bandwidth wet-process low-reflection film in one embodiment of the present invention;

[0020] Figure 2This is a reflectance curve of the large-bandwidth wet-process low-reflection film in Embodiment 1 of this utility model;

[0021] Figure 3 This is a reflectance curve of the large-bandwidth wet-process low-reflection film in Embodiment 2 of this utility model;

[0022] Figure 4 This is a reflectance curve of the large-bandwidth wet-process low-reflection film in Embodiment 3 of this utility model;

[0023] Figure 5 The reflectance curve of the large-bandwidth wet-process low-reflection film in Comparative Example 1 of this utility model is shown.

[0024] Figure 6 This is a reflectance curve of the large-bandwidth wet-process low-reflection film in Comparative Example 2 of this invention.

[0025] Explanation of key figure labels:

[0026] 1. Substrate layer; 2. Hardening coating; 3. High refractive index coating; 4. Bandwidth widening layer; 5. Low refractive index coating. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0028] A specific embodiment of this utility model provides a large-bandwidth wet-process low-reflection thin film, such as... Figure 1 As shown, it includes a substrate layer 1, a hardening coating 2, a high refractive index coating 3, a bandwidth widening layer 4, and a low refractive index coating 5, which are stacked sequentially; wherein, the refractive index of the high refractive index coating 3 is 1.65-1.75, the refractive index of the bandwidth widening layer 4 is 2.0-2.5, and the refractive index of the low refractive index coating 5 is 1.30-1.35.

[0029] Specifically, this invention employs a four-layer structure consisting of a hardening coating, a high refractive index coating, a bandwidth widening layer, and a low refractive index coating on a substrate layer. The high refractive index of the bandwidth widening layer significantly increases the working bandwidth of the thin film. Simultaneously, the combination of the high refractive index coating and the low refractive index coating effectively reduces the average reflectivity and Y-value (visual reflectivity) of the thin film, enabling it to be used in more advanced application scenarios.

[0030] Furthermore, the substrate layer is a TAC layer. The thickness of the TAC (cellulose triacetate) substrate can be selected as 40μm, 60μm, or 80μm. Based on the total light transmittance and haze of the TAC substrate, a TAC substrate with a total light transmittance of over 90% and a haze of less than 0.6% is preferred.

[0031] Furthermore, the hardening coating is an acrylic layer with a thickness of 3μm-5μm and a refractive index of 1.50-1.55.

[0032] Specifically, a hardening coating is applied to provide overall hardness to the film, improving its abrasion resistance and weather resistance. Furthermore, the refractive index of the TAC substrate is typically 1.5-1.55; to match the TAC substrate and prevent "rainbow patterns," the refractive index of the hardening coating is selected to be 1.50-1.55. The material used for the hardening coating is an epoxy acrylate polymer, model number Arakawa Chemical CHT-X1-NS.

[0033] Furthermore, the high refractive index coating is a polyurethane resin layer with a thickness of 120nm-150nm and a refractive index of 1.65-1.75.

[0034] Specifically, high-refractive-index coatings help reduce the reflectivity of the thin film while also ensuring its superior flexibility and weather resistance. The raw material used in the high-refractive-index coating is epoxy polyurethane resin, model number Halima UVH-D-ZR-165-32.

[0035] Furthermore, the bandwidth-enhancing layer is a niobium pentoxide coating, a titanium dioxide coating, or a zirconium dioxide coating, with a thickness of 2nm-8nm and a refractive index of 2.0-2.5.

[0036] Specifically, niobium pentoxide (Nb2O5), titanium dioxide (TiO2), and zirconium dioxide (ZrO2) all have high refractive indices. Placing a bandwidth-enhancing layer composed of these materials between the high-refractive-index coating and the low-refractive-index coating can greatly broaden the working bandwidth and reduce the reflectivity and Y value of the thin film.

[0037] Furthermore, the low-refractive-index coating is an acrylic resin layer with a thickness of 95nm-110nm and a refractive index of 1.30-1.35.

[0038] Specifically, choosing an acrylic resin layer can ensure that the film has better light transmittance and weather resistance. The acrylic resin is specifically a siloxane acrylic resin, model number Arakawa Chemical SL045.

[0039] The present invention will be further described in detail below with reference to specific implementations.

[0040] Example 1

[0041] The substrate selected is TAC substrate with a thickness of 40μm. First, a 4μm thick HC hardening coating with a refractive index of 1.52 is applied on top of the TAC substrate layer using a precision wet coating process. Next, a 125nm thick high refractive index coating with a refractive index of 1.65 is applied on top of the HC hardening coating using a precision wet coating process. Then, a 4nm thick bandwidth broadening layer with a refractive index of 2.1 is deposited on top of the high refractive index coating using a magnetron sputtering process. The material used is niobium pentoxide. Finally, a 100nm thick low refractive index coating with a refractive index of 1.33 is applied on top of the bandwidth broadening layer using a precision wet coating process to obtain a wide-bandwidth wet low-reflection film.

[0042] In this embodiment, the wide-bandwidth wet low-reflection film has an average reflectance of 0.35% in the 380-780nm band and a reflectance of 0.067% in the 550nm band. The working bandwidth is (445-645)nm, and the average reflectance in the working bandwidth band is 0.09%, with a Y value of 0.07%.

[0043] Example 2

[0044] The substrate selected is TAC substrate with a thickness of 60μm. First, a 3μm thick HC hardening coating with a refractive index of 1.54 is applied on top of the TAC substrate layer using a precision wet coating process. Next, a 135nm thick high refractive index coating with a refractive index of 1.68 is applied on top of the HC hardening coating using a precision wet coating process. Then, a 6nm thick bandwidth broadening layer with a refractive index of 2.2 is deposited on top of the high refractive index coating using a magnetron sputtering process. The material used is titanium dioxide. Finally, a 105nm thick low refractive index coating with a refractive index of 1.34 is applied on top of the bandwidth broadening layer using a precision wet coating process to obtain a wide-bandwidth wet low-reflection film.

[0045] In this embodiment, the wide-bandwidth wet low-reflection film has an average reflectance of 0.33% in the 380-780nm band and a reflectance of 0.059% in the 550nm band. The working bandwidth is (430-660)nm, and the average reflectance in the working bandwidth band is 0.075%, with a Y value of 0.065%.

[0046] Example 3

[0047] The substrate selected is TAC substrate with a thickness of 60μm. First, a 4μm thick HC hardening coating with a refractive index of 1.53 is applied on top of the TAC substrate layer using a precision wet coating process. Next, a 140nm thick high refractive index coating with a refractive index of 1.70 is applied on top of the HC hardening coating using a precision wet coating process. Then, a 5nm thick bandwidth broadening layer with a refractive index of 2.3 is deposited on top of the high refractive index coating using a magnetron sputtering process. The material used is zirconium dioxide. Finally, a 102nm thick low refractive index coating with a refractive index of 1.31 is applied on top of the bandwidth broadening layer using a precision wet coating process to obtain a wide-bandwidth wet low-reflection film.

[0048] In this embodiment, the wide-bandwidth wet low-reflection film has an average reflectance of 0.31% in the 380-780nm band and a reflectance of 0.054% in the 550nm band. The working bandwidth is (430-660)nm, and the average reflectance in the working bandwidth band is 0.069%, with a Y value of 0.057%.

[0049] Comparative Example 1

[0050] The substrate selected is TAC substrate with a thickness of 60μm. First, a 4μm thick HC hardening coating with a refractive index of 1.52 is coated on the TAC substrate layer using a precision wet coating process. Then, a 100nm thick low refractive index coating with a refractive index of 1.33 is coated on the HC hardening coating using a precision wet coating process to obtain a wet low-reflection film.

[0051] In this comparative example, the wet-process low-reflection film has an average reflectance of 1.03% in the 380-780nm band and a reflectance of 0.68% in the 550nm band. The working bandwidth is (525-575)nm, and the average reflectance in the working bandwidth band is 0.72%, with a Y value of 0.71%.

[0052] Comparative Example 2

[0053] The substrate selected is TAC substrate with a thickness of 60μm. First, a 4μm thick HC hardening coating with a refractive index of 1.52 is applied on top of the TAC substrate layer using a precision wet coating process. Next, a 150nm thick high refractive index coating with a refractive index of 1.65 is applied on top of the HC hardening coating using a precision wet coating process. Finally, a 100nm thick low refractive index coating with a refractive index of 1.33 is applied on top of the high refractive index coating using a precision wet coating process to obtain a wet low-reflection film.

[0054] The wet low-reflection film in this comparative example has an average reflectance of 0.55% in the 380-780nm band and a reflectance of 0.54% in the 550nm band. The working bandwidth is (520-580)nm, and the average reflectance in the working bandwidth band is 0.57%, with a Y value of 0.58%.

[0055] Operating bandwidth typically refers to the range of light wavelengths with reflectance centered at 550nm, where the reflectance falls within [R(550nm)±0.05%]. The thin film in Comparative Example 1 consists of two layers: an HC hardening coating and a low-refractive-index coating. As can be seen from the reflectance curve, the two-layer film only exhibits the lowest reflectance at 550nm; the reflectance is higher in other wavelengths. This results in a very narrow operating bandwidth for the two-layer structure, which cannot meet the needs of many applications.

[0056] In Comparative Example 2, a high-refractive-index coating was added between the HC hardening coating and the low-refractive-index coating to form a three-layer structure. As can be seen from the reflectance curve, although the reflectance in the wavelength range (450-650) nm is relatively low, a small peak is formed near the 500 nm wavelength range. Therefore, the working bandwidth of the three-layer structure film is also relatively narrow, resulting in a large average reflectance and Y value, which cannot meet the needs of more application scenarios.

[0057] from Figures 2-4 As can be seen, the reflectivity of the thin film in this embodiment of the invention exhibits slight fluctuations around the reflectivity at 550nm, centered on the reflectivity at 450-650nm. This eliminates the peak near 500nm in the three-layer thin film, ensuring that the reflectivity in the (450-650)nm band is centered on the reflectivity at 550nm, thus broadening the required operating bandwidth. Compared to two-layer and three-layer thin films, the thin film in this invention significantly broadens the operating bandwidth and reduces the reflectivity and Y-value, enabling its application in more advanced application scenarios.

[0058] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0059] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A wide-bandwidth wet-process low-reflection thin film, characterized in that, It includes a substrate layer, a hardening coating, a high refractive index coating, a bandwidth broadening layer and a low refractive index coating, which are stacked sequentially. The high refractive index coating has a refractive index of 1.65-1.75, the bandwidth widening layer has a refractive index of 2.0-2.5, and the low refractive index coating has a refractive index of 1.30-1.

35.

2. The large bandwidth wet-process low-reflection thin film according to claim 1, characterized in that, The bandwidth widening layer is a niobium pentoxide coating, a titanium dioxide coating, or a zirconium dioxide coating.

3. The large bandwidth wet-process low-reflection thin film according to claim 1, characterized in that, The thickness of the bandwidth broadening layer is 2nm-8nm.

4. The large bandwidth wet-process low-reflection thin film according to claim 1, characterized in that, The high refractive index coating is a polyurethane resin layer with a thickness of 120nm-150nm.

5. The large bandwidth wet-process low-reflection thin film according to claim 1, characterized in that, The low refractive index coating is an acrylic resin layer with a thickness of 95nm-110nm.

6. The large bandwidth wet-process low-reflection thin film according to claim 1, characterized in that, The refractive index of the hardened coating is 1.50-1.

55.

7. The large bandwidth wet-process low-reflection thin film according to claim 6, characterized in that, The hardening coating is an acrylic layer with a thickness of 3μm-5μm.

8. The large bandwidth wet-process low-reflection thin film according to claim 1, characterized in that, The substrate layer is a TAC layer.

Images