A transparent hard coating capable of reducing blue light and its preparation process

Abstract

The present invention relates to the technical field of surface coatings, and specifically discloses a transparent hard coating capable of reducing blue light and a preparation process thereof. Reactive magnetron sputtering technology is adopted to deposit a single-layer transparent hard coating on the surface of a substrate. Element doping and thin-film interference principles are utilized to achieve a good effect of reducing the transmittance of blue light. The operation is simple, and the prepared coating has high hardness, which improves the wear resistance of the coating. At the same time, by regulating the process parameters of the magnetron sputtering, the ratio of SiN to AlN can be precisely adjusted, thereby adjusting the transmittance of the coating to blue light of different wavelengths and other visible light. The coating has strong controllability, especially reducing the transmittance of harmful short-wavelength blue light, thereby protecting eyesight. While beneficial long-wavelength blue light can penetrate more of the coating, the coating has a good transmittance to other visible light, which is beneficial to the clarity and authenticity of color rendering.

Description

Technical Field

[0001] The present invention relates to the technical field of surface coatings, and in particular to a transparent hard coating capable of reducing blue light and a preparation process thereof. Background Art

[0002] With the increasing prevalence of electronic products, the accompanying problems and hidden dangers have become more pronounced. Blue light damage, such as eye discomfort and vision loss, has gradually attracted widespread attention. Blue light in visible light, due to its short wavelength, high energy, and strong penetrating power, can easily cause damage to the human eye. Commonly used devices such as mobile phones, computers, tablets, and televisions are sources of blue light damage. Therefore, anti-blue light technology to protect vision and safeguard eye health has become a topic of concern in the electronics industry. Research on various treatments and preventions for eye damage caused by blue light has also become a research and development hotspot in the field of visual health. On the one hand, various anti-blue light screens and anti-blue light films are used to reduce the blue light radiated by electronic devices. On the other hand, anti-blue light glasses are used to protect the eyes and reduce the amount of blue light transmitted to the human eye.

[0003] Currently, blue light protection technologies mainly include absorption and reflection. Absorption-based blue light protection achieves blue light protection by adding a blue light absorber to the substrate or by adding a blue light absorbing material to a film coated on the substrate. For example, patent publication CN104375285B discloses a blue light protection lens that absorbs blue light by applying a neodymium-praseodymium mixture film layer and a titanium dioxide and indium trioxide mixture film layer on the lens. Finally, palladium is evaporated on the outermost layer to form a reflective film. However, the outermost palladium layer has a low hardness and is easily worn during long-term use. Therefore, the wear resistance of the film needs to be improved. The reflective anti-blue light technology mainly deposits multiple layers of films on the surface of the substrate in sequence, and sets the material, refractive index and thickness of each film layer so that the coherent cancellation of the blue light band can be achieved between the multiple films, thereby reducing the transmittance of blue light and achieving the effect of anti-blue light. In addition, a hardening layer is set on the anti-blue light layer to improve the hardness and wear resistance. For example, the patent document with publication number CN110568529A discloses a hardened anti-blue light lens, which is formed by setting a composite layer, an anti-blue light layer, a silicon oxide layer and an oxide layer on the lens. The zirconium layer utilizes the tin oxide, cerium dioxide, palladium dioxide and platinum dioxide compounds inside the composite layer to work together with the titanium oxide, bismuth oxide, potassium fluoride and other compounds inside the anti-blue light layer, and then cooperates with the silicon oxide layer on one side of the anti-blue light layer and the zirconium oxide layer on the surface of the silicon oxide layer to increase the anti-blue light effect and hardness of the lens. However, the preparation process is complicated and requires multiple layers of composite layer, anti-blue light layer, silicon oxide layer and zirconium oxide layer to achieve the hardened anti-blue light effect, which increases the difficulty of thin film preparation.

[0004] It can be seen that in order to address the defect of difficulty in preparing blue light attenuating films in related technologies, it is urgent to provide a new preparation process for blue light attenuating films, which is simple to prepare and can achieve high hardness while attenuating blue light. Summary of the Invention

[0005] The purpose of the present invention is to provide a transparent hard coating and preparation process that can reduce blue light, which can improve the defect that the preparation of the blue light-reducing film is difficult, and the prepared film can reduce blue light while having high hardness.

[0006] In a first aspect, the present invention provides a process for preparing a transparent hard coating that can reduce blue light, comprising the following preparation steps: placing a substrate in a chamber of a magnetron sputtering system, introducing argon and nitrogen after vacuuming, turning on the power of an aluminum target and a silicon target for co-deposition, and preparing a transparent hard coating, wherein the sputtering power of the aluminum target is 280-320 W, the sputtering power of the silicon target is 28-55 W, the flow rate of the argon gas is 20-60 sccm, the flow rate of the nitrogen gas is 3-10 sccm, and the sputtering time is 50 to 100 minutes.

[0007] Optionally, the sputtering power of the aluminum target is 290-310 W, the sputtering power of the silicon target is 28-52 W, the flow rate of the argon gas is 35-45 sccm, the flow rate of the nitrogen gas is 3-10 sccm, and the sputtering time is 55-90 min.

[0008] In a second aspect, the present invention provides a transparent hard coating capable of reducing blue light, which is prepared by the aforementioned process for preparing a transparent hard coating capable of reducing blue light.

[0009] Optionally, the elemental composition of the transparent hard coating includes Al, Si and N.

[0010] Optionally, the molar ratio of SiN to AlN in the transparent hard coating is 2.8 to 5, calculated based on the atomic ratio of N-Al bonds to N-Si bonds.

[0011] Optionally, the hardness of the transparent hard coating is 18 to 24 GPa.

[0012] Optionally, the transparent hard coating has a blue light transmittance of 72% to 80% at a wavelength of 415 to 455 nm, and a blue light transmittance of 74% to 90% at a wavelength of 455 to 500 nm.

[0013] Optionally, the transparent hard coating has a blue light transmittance of 72-75% at 415-455 nm and a blue light transmittance of 75-85% at 455-500 nm.

[0014] Optionally, the transparent hard coating has a visible light transmittance of 85% to 90% in the range of 500 to 540 nm.

[0015] Optionally, the transparent hard coating has a thickness of 200 to 240 nm.

[0016] In summary, the present invention has the following beneficial effects:

[0017] 1. The present invention provides a process for preparing a transparent hard coating capable of reducing blue light. The process is simple to operate and utilizes reactive magnetron sputtering technology to deposit a single-layer transparent hard coating on a substrate surface. Utilizing the principles of element doping and thin-film interference, the process effectively reduces blue light transmittance. In subsequent examples, it was determined that the attenuation effect on harmful blue light of 415 to 455 nm can reach over 20%, and preferably, over 25%.

[0018] 2. The present invention provides a preparation process for a transparent hard coating that can reduce blue light. The process uses aluminum and silicon targets for co-deposition, and nitrogen and argon gases are introduced. By regulating the process parameters of magnetron sputtering, the ratio of SiN to AlN can be precisely adjusted, thereby adjusting the transmittance of the film to blue light of different wavelengths and other visible light. The process has strong controllability, especially reducing the transmittance of harmful blue light in the short-wave band (wavelength 415-455nm), protecting eyesight, while beneficial blue light in the long-wave band (wavelength 455-500nm) can penetrate the coating more. The process also has good transmittance for other visible light (wavelength 500-540nm), which is beneficial to the clarity and authenticity of color rendering, as well as the regulation of melatonin and circadian rhythm.

[0019] 3. The transparent hard coating that can reduce blue light provided by the present invention has the characteristics of good attenuation of harmful blue light transmittance and high surface hardness. The nano-level coating has excellent bonding strength with the substrate, which greatly improves the defect of easy wear and failure of the film caused by low film hardness and weak film-base bonding. In subsequent embodiments, the hardness of the substrate was measured to be 7.21 GPa, and after the transparent hard coating was formed on the surface of the substrate, the hardness was increased to more than 20 GPa, and preferably, it can reach 22.94 GPa. The hardness of the material is significantly improved and the wear resistance is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic cross-sectional view of a substrate and a coating according to an embodiment of the present invention;

[0021] Figure 2 These are photos of the sample coatings of Examples 1-2 and Comparative Examples 1-5 of the present invention;

[0022] Figure 3It is the XPS full element scanning diagram of the coating of the sample of Example 1 of the present invention and Comparative Example 2;

[0023] Figure 4 is a curve showing the variation of transmittance of the sample coating of Example 1-2 of the present invention with the wavelength of visible light;

[0024] Figure 5 1 is a curve showing the variation of transmittance of the coatings of the samples of Comparative Examples 1-5 of the present invention with the wavelength of visible light;

[0025] Figure 6 1-2 are the loading and unloading curves of the sample coatings of Comparative Examples 1-5 and Examples 1-2 of the present invention;

[0026] Figure 7 The surface hardness of the coating of the samples of Examples 1-2 and Comparative Examples 1-5 of the present invention varies with the indentation depth;

[0027] Description of reference numerals: 10, substrate; 20, transparent hard coating layer. DETAILED DESCRIPTION

[0028] Blue light has a wavelength of 400-500nm. Existing research shows that short-wavelength blue light in the 415-445nm band has high energy and can penetrate the cornea and lens directly to the retina. Excessive exposure increases the risk of macular degeneration, exacerbating color aberration and blurred vision, and impairing vision. Furthermore, short-wavelength blue light inhibits melatonin secretion and alters the body's circadian rhythms. Therefore, short-wavelength blue light in the 415-445nm band is called harmful blue light. Long-wavelength blue light in the 445-500nm band helps regulate melatonin secretion and circadian rhythms, and is relatively beneficial for normal color vision and pupil constriction. Therefore, long-wavelength blue light in the 445-500nm band is called beneficial blue light. The current main preparation process for anti-blue light films is relatively complex. In addition to setting up multiple layers of coherent films to achieve blue light attenuation, a separate outermost transparent hardening layer, such as TiO2 or SiO2, is required. However, the hardness of the hardening layer is still below 10GPa.

[0029] After a long period of research, the inventor surprisingly found that by using reactive magnetron sputtering technology, such as Figure 1 As shown, a single-layer transparent hard coating 20 is deposited on the surface of a substrate 10. By utilizing element doping and thin-film interference, it effectively reduces the transmittance of blue light, particularly harmful short-wavelength blue light. This allows more beneficial long-wavelength blue light to penetrate the coating, while maintaining good transmittance for the rest of the visible light spectrum, facilitating color rendering. Furthermore, the transparent hard coating exhibits a high surface hardness exceeding 20 GPa, significantly reducing the film's susceptibility to wear and failure.

[0030] In some embodiments of the present invention, a process for preparing a transparent hard coating that can reduce blue light includes the following preparation steps: placing a substrate in a chamber of a magnetron sputtering system, introducing argon and nitrogen after vacuuming, turning on the power of the aluminum target and the silicon target for co-deposition to prepare a transparent hard coating, wherein the sputtering power of the aluminum target is 280-320W, the sputtering power of the silicon target is 28-55W, the flow rate of the argon gas is 20-60sccm, the flow rate of the nitrogen gas is 3-10sccm, and the sputtering time is 50-100min. By adjusting the process parameters of magnetron sputtering and controlling the reaction co-deposition rate of aluminum, nitrogen and silicon, a single-layer transparent hard coating is prepared on the surface of the substrate. By utilizing the principles of element doping and thin film interference, a good effect of reducing the transmittance of blue light can be achieved. In particular, by adjusting the ratio of SiN and AlN in the coating, the transmittance of the coating to blue light and visible light in different bands is achieved, so that the transmittance of harmful blue light is significantly reduced, while the transmittance of beneficial blue light and other visible light can maintain high transmittance. In addition, the hardness of the coating can be increased, further improving the wear resistance of the coating.

[0031] In some embodiments of the present invention, the sputtering power of the aluminum target is 290-310W, the sputtering power of the silicon target is 28-52W, the argon flow rate is 35-45sccm, the nitrogen flow rate is 3-10sccm, and the sputtering time is 55-90 minutes. By precisely controlling the process parameters of magnetron sputtering, the coating's ability to reduce harmful blue light, its transmittance of beneficial blue light and visible light, and its hardness can be further optimized.

[0032] In some embodiments of the present invention, a transparent hard coating capable of reducing blue light is prepared by the aforementioned process for preparing a transparent hard coating capable of reducing blue light.

[0033] In some embodiments of the present invention, the elemental composition of the transparent hard coating layer includes Al, Si, and N.

[0034] In some embodiments of the present invention, the molar ratio of SiN to AlN in the transparent hard coating is 2.8 to 5, calculated as the atomic ratio of N-Al bonds to N-Si bonds; preferably, the molar ratio of SiN to AlN is 3 to 4.5.

[0035] In some embodiments of the present invention, the hardness of the transparent hard coating layer is 18 to 24 GPa; preferably, the hardness of the transparent hard coating layer is 20 to 24 GPa.

[0036] In some embodiments of the present invention, the blue light transmittance of the transparent hard coating layer is 72-80% at 415-455 nm, and the blue light transmittance at 455-500 nm is 74-90%.

[0037] In some embodiments of the present invention, the blue light transmittance of the transparent hard coating layer is 72-75% at 415-455 nm, and the blue light transmittance at 455-500 nm is 75-85%.

[0038] In some embodiments of the present invention, the transparent hard coating has a remaining visible light transmittance of 85% to 90% in the range of 500 to 540 nm, preferably 85% to 89%.

[0039] In some embodiments of the present invention, the thickness of the transparent hard coating layer is 200-240 nm, preferably 210-230 nm.

[0040] The present invention is described in detail below with reference to specific examples and comparative examples. In the following examples and comparative examples, electronic grade transparent glass (SiO2 material, electronic grade glass, sample is square, side length is 20mm, thickness is 1.1mm) is used as the substrate, and magnetron sputtering technology is used for preparation. The substrate is placed in the chamber of the magnetron sputtering system and evacuated to 5*10 - 6 Torr, before turning on the target gun power for deposition, argon gas is introduced, the argon gas flow rate is controlled to 40sccm, the RF bias is controlled to 100W, and the substrate surface is glow discharge cleaned for 10 minutes to remove contaminants on the substrate surface.

[0041] Example 1

[0042] After the substrate is glow discharge cleaned, the argon flow rate is maintained at 40 sccm, and nitrogen is introduced at the same time, and the nitrogen flow rate is controlled to 5 sccm. Then, the target gun power is turned on, and the AC power supply power of the aluminum target is controlled to RF300W, and the DC power supply power of the silicon target is controlled to DC30W. Reactive sputtering is performed for 85 minutes. After sputtering is completed, it is taken out to prepare sample A-1. The coating thickness of sample A-1 is measured to be 228 nm. The specific process parameters can be referred to Table 1.

[0043] Table 1. Process parameters of magnetron sputtering transparent hard coating

[0044]

[0045] Example 2

[0046] Referring to Table 1, the difference between Example 2 and Example 1 is that the DC power supply power of the silicon target in Example 2 is DC50W, the nitrogen flow rate is 8sccm, the sputtering time is 60min, and the remaining preparation steps are the same as those in Example 1. After sputtering is completed, sample A-2 is prepared, and the coating thickness of sample A-2 is measured to be 215nm.

[0047] Comparative Example 1

[0048] Referring to Table 1, the difference between Comparative Example 1 and Example 1 is that the substrate of Comparative Example 1 is not subjected to magnetron sputtering deposition coating, and is marked as Sample B-1.

[0049] Comparative Example 2

[0050] Referring to Table 1, the difference between Comparative Example 2 and Example 2 is that the DC power supply power of the silicon target in Comparative Example 2 is 0 W, and the remaining preparation steps are the same as those in Example 2. After sputtering is completed, sample B-2 is prepared, and the coating thickness of sample B-2 is measured to be 105 nm.

[0051] Comparative Example 3

[0052] Referring to Table 1, the difference between Comparative Example 3 and Example 1 is that the DC power supply power of the silicon target in Comparative Example 3 is 0 W, and the DC power supply power of the chromium target is DC40 W. The remaining preparation steps are the same as those in Example 1. After sputtering is completed, sample B-3 is prepared, and the coating thickness of sample B-3 is measured to be 375 nm.

[0053] Comparative Example 4

[0054] Referring to Table 1, the difference between Comparative Example 4 and Example 2 is that the DC power supply power of the silicon target in Comparative Example 4 is DC25W, and the remaining preparation steps are the same as those in Example 2. After sputtering is completed, sample B-4 is prepared, and the coating thickness of sample B-4 is measured to be 170nm.

[0055] Comparative Example 5

[0056] Referring to Table 1, the difference between Comparative Example 5 and Example 2 is that the DC power supply power of the silicon target in Comparative Example 5 is DC75W, and the remaining preparation steps are the same as those in Example 2. After sputtering is completed, sample B-5 is prepared, and the coating thickness of sample B-5 is measured to be 245nm.

[0057] Figure 2 The sample images of Examples 1, 2 and Comparative Examples 1-5 are shown in Figure 1. Figure 1 It can be seen that the coating of sample A-1 of Example 1 is a light blue transparent coating, the coating of sample A-2 of Example 2 is a light green transparent coating, sample B-1 of comparative example 1 is a transparent glass substrate, sample B-2 of comparative example 2 is a light purple transparent coating, sample B-3 of comparative example 3 is an opaque brown coating, sample B-4 of comparative example 4 is a light orange transparent coating, and sample B-5 of comparative example 5 is a light yellow transparent coating.

[0058] The elemental compositions of the samples in the examples and comparative examples of the present application were measured using an X-ray photoelectron spectrometer (XPS) from Thermo Fisher Scientific. Figure 3 The XPS test diagrams of the sample coatings of Example 1 and Comparative Example 2 are shown in FIG. Figure 3 It can be seen that the elemental composition detected in the sample coating of Example 1 includes Al, Si and N, as well as C and O. The elemental composition detected in the sample coating of Comparative Example 2 includes Al and N, as well as C and O. The elements detected in the sample coating of Example 2 and Comparative Examples 4 and 5 are the same as those detected in the sample coating of Example 1, and the elemental composition includes Al, Si and N, as well as C and O. Among them, the above-mentioned C and O elements all come from the air adsorbed on the surface of the sample coating when the sample is exposed to the air.

[0059] Analysis of the XPS test results shows that the atomic ratio of N-Si bonds and N-Al bonds in the coating of sample A-1 of Example 1 is 4.5, and the amount ratio of SiN and AlN in the coating is 4.5 based on the atomic ratio of N-Si bonds and N-Al bonds; the atomic ratio of N-Si bonds and N-Al bonds in the coating of sample A-2 of Example 2 is 3, and the amount ratio of SiN and AlN in the coating is 3 based on the atomic ratio of N-Si bonds and N-Al bonds; the atomic ratio of N-Si bonds and N-Al bonds in the coating of sample B-3 of Comparative Example 4 is 2.4, and the amount ratio of SiN and AlN in the coating is 2.4 based on the atomic ratio of N-Si bonds and N-Al bonds; the atomic ratio of N-Si bonds and N-Al bonds in the coating of sample B-4 of Comparative Example 5 is 1.5, and the amount ratio of SiN and AlN in the coating is 1.5 based on the atomic ratio of N-Si bonds and N-Al bonds.

[0060] The transmission spectra of the samples in the examples and comparative examples of the present application were measured using a Cary 5000 UV-visible-near-infrared spectrophotometer from Agilent Technologies, USA. The baseline correction signal was obtained from an empty stage without a sample placed thereon. The curve of the transmittance of the sample coatings in the examples as a function of visible light wavelength is shown in FIG. Figure 4 As shown in the figure, the curve of the transmittance of the comparative sample coating as a function of visible light wavelength is shown in Figure 5 Specific visible light transmittance data are shown in Table 2.

[0061] The hardness of the samples in the examples and comparative examples of the present application was measured using the continuous stiffness module of the G200 nanoindenter produced by KLA Corporation of the United States. Figure 6 1 is the loading and unloading curve of the coating of the embodiment of the present invention and the comparative example sample; Figure 7 2 is a curve showing the change of surface hardness of the coating of the embodiment of the present invention and the comparative example sample with the indentation depth. The specific hardness data are shown in Table 2.

[0062] Table 2. Hardness and visible light transmittance of the coatings of Examples 1-2 and Comparative Examples 1-5

[0063]

[0064] As can be seen from Table 2, the hardness of the glass substrate of Comparative Example 1 without magnetron sputtering deposition coating is 7.21 GPa, and the hardness of the coatings of the samples of Comparative Examples 2-5 are all better than the glass substrate of Comparative Example 1. In particular, the hardness of the coatings of the samples of Examples 1 and 2 is above 20 GPa, which is much higher than the hardness of the glass substrate of Comparative Example 1.

[0065] As can be seen from Table 2, the glass substrate of Comparative Example 1 has similar transmittances for visible light in various wavelength bands, with no significant difference. The transmittances are all around 89%. This shows that the glass substrate of Comparative Example 1 cannot reduce blue light.

[0066] The transmittance of the sample coating of Comparative Example 2 to harmful blue light and beneficial blue light is close, both between 88 and 89.9%, while the transmittance of the remaining visible light is between 86.0 and 88.5%. It can be seen that the sample coating of Comparative Example 2 cannot reduce blue light, but instead reduces the transmittance of the remaining visible light.

[0067] The coating of the sample in comparative example 3 can significantly reduce the transmittance of harmful blue light, beneficial blue light and other visible light, making the coating of the sample in comparative example 3 opaque.

[0068] The coating of the sample in Comparative Example 4 can significantly reduce harmful blue light, reducing the transmittance of harmful blue light to 73.4-78.1%. However, it also reduces the transmittance of beneficial blue light and other visible light, resulting in the transmittance of beneficial blue light and other visible light being lower than that of harmful blue light.

[0069] The coating of the sample in Comparative Example 5 can attenuate harmful blue light, but the attenuation effect is not obvious. The transmittance of harmful blue light is 76.1-86.9%, while the transmittance of beneficial blue light and other visible light is significantly reduced, with transmittances of 73.5-76.1% and 75.0-82.0%, respectively, which are lower than the transmittance of harmful blue light.

[0070] The sample coating of Example 1 can significantly reduce harmful blue light, with a transmittance of harmful blue light of 72.7% to 79.8%. At the same time, it can maintain the transmittance of beneficial blue light and other visible light, so that the beneficial blue light and other visible light are maintained at 79.8% to 89.3% and 87.5% to 89.3%, respectively. This achieves the goal of reducing harmful blue light and protecting eyesight while maintaining a high transmittance for beneficial blue light and other visible light, which is beneficial to the clarity and authenticity of color rendering, as well as to melatonin secretion and circadian rhythm regulation.

[0071] The sample coating of Example 2 can significantly reduce harmful blue light, with a harmful blue light transmittance of 72.1% to 74.6%. At the same time, it can transmit beneficial blue light and other visible light, so that the beneficial blue light and other visible light are maintained at 74.6% to 85.0% and 85.0% to 88.9% respectively. It achieves the goal of reducing harmful blue light and protecting eyesight while maintaining a high transmittance for beneficial blue light and other visible light, which is beneficial to the clarity and authenticity of color rendering, as well as to melatonin secretion and circadian rhythm regulation.

[0072] The transparent hard coating of the embodiment of the present application can be used alone as a functional film to reduce blue light, or as the outermost layer of a composite structure of a functional film to prevent blue light, thereby reducing the blue light transmittance of the film while improving the hardness of the film.

[0073] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A process for preparing a transparent hard coating capable of reducing blue light, characterized in that: The method comprises the following preparation steps: placing a substrate in a chamber of a magnetron sputtering system, introducing argon and nitrogen after evacuation, turning on the power of an aluminum target and a silicon target for co-deposition, and preparing a transparent hard coating, wherein the RF sputtering power of the aluminum target is 280-320 W, the DC sputtering power of the silicon target is 28-55 W, the flow rate of the argon gas is 20-60 sccm, the flow rate of the nitrogen gas is 3-10 sccm, and the sputtering time is 50-100 minutes.

2. The process for preparing a transparent hard coating capable of reducing blue light according to claim 1, wherein: The sputtering power of the aluminum target is 290-310 W, the sputtering power of the silicon target is 28-52 W, the flow rate of the argon gas is 35-45 sccm, the flow rate of the nitrogen gas is 3-10 sccm, and the sputtering time is 55-90 min.

3. A transparent hard coating capable of reducing blue light, prepared by the preparation process of the transparent hard coating capable of reducing blue light according to claim 1 or 2.

4. The transparent hard coating capable of reducing blue light according to claim 3, characterized in that: The elemental composition of the transparent hard coating layer includes Al, Si and N.

5. The transparent hard coating capable of reducing blue light according to claim 3, wherein: The molar ratio of SiN to AlN in the transparent hard coating layer is 2.8 to 5, calculated as the atomic ratio of N-Al bonds to N-Si bonds.

6. The transparent hard coating capable of reducing blue light according to claim 3, characterized in that: The hardness of the transparent hard coating is 18 to 24 GPa.

7. The transparent hard coating capable of reducing blue light according to claim 3, wherein: The transparent hard coating has a blue light transmittance of 72-80% at a wavelength of 415-455 nm and a blue light transmittance of 74-90% at a wavelength of 455-500 nm.

8. The transparent hard coating capable of reducing blue light according to claim 7, characterized in that: The transparent hard coating has a blue light transmittance of 72-75% at a wavelength of 415-455 nm and a blue light transmittance of 75-85% at a wavelength of 455-500 nm.

9. The transparent hard coating capable of reducing blue light according to claim 7, wherein: The transparent hard coating has a visible light transmittance of 85-90% in the range of 500-540 nm.

10. The transparent hard coating capable of reducing blue light according to claim 3, wherein: The thickness of the transparent hard coating is 200-240 nm.

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