Infrared reflective cover glass

Abstract

The present invention relates to an infrared reflective cover glass, and more specifically, to an infrared reflective cover glass that protects an imaging device, wherein a plurality of low-refractive-index layers or high-refractive-index layers are formed in an alternating structure on a transparent support substrate that transmits light, and thereby performs low reflection of visible light and reflection in the infrared region, thereby reducing flare and ghosting phenomena of the imaging element and improving the durability of the cover glass through the rigidity of the reinforced thin film. The front thin film of the infrared reflective cover glass of the present invention for solving the above technical problem comprises a first high-refractive-index layer disposed furthest from the support substrate and a second high-refractive-index layer disposed thereafter, and the first high-refractive-index layer may have a higher refractive index than the second high-refractive-index layer.

Description

Technology Field

[0001] The present invention relates to an infrared reflective cover glass, and more specifically, to an infrared reflective cover glass that protects an imaging device, wherein a plurality of low-refractive-index layers or high-refractive-index layers are formed in an alternating structure on a transparent support substrate that transmits light, and thereby performs low reflection of visible light and reflection in the infrared region, thereby reducing flare and ghosting phenomena of the imaging element and improving the durability of the cover glass through the rigidity of the reinforced thin film. Background Technology

[0002] Generally, a cover glass for protecting a camera formed of a lens and an image sensor must satisfy optical characteristics including low reflection performance of visible light and scratch or wear resistance performance.

[0003] Products requiring a cover glass with a protective thin film coating to satisfy the above performance include portable devices such as smartphones, tablet computers, and laptop computers.

[0004] A thin film coating is applied by selecting a material with appropriate hardness so that it can have sufficient hardness and high transmittance at the same time as a protective cover glass.

[0005] To satisfy these requirements, the thin film formed on the surface of a transparent glass support substrate must be coated with a material having the same refractive index as glass.

[0006] However, since there is no single material that matches the refractive index n=1.5 (λ=550nm) of glass while possessing sufficiently high hardness, a high-refractive-index material with scratch resistance is coated. In this case, because this material has a higher refractive index than glass, its reflectivity increases; to resolve this issue, multiple low-refractive-index or high-refractive-index layers are formed in an alternating structure on the support substrate.

[0007] Figure 1 is a schematic diagram illustrating the structure of a typical cover glass and camera.

[0008] The human eye is sensitive to light in the visible region (visible light) with a wavelength of 420 nm to 700 nm. Meanwhile, an imaging element (230), such as CMOS, generally contains visible light and is sensitive to longer wavelengths of light, namely light with a wavelength of about 1.1 μm. Therefore, if an image captured by the imaging element (230) is taken as a photograph, it does not appear to the human eye as having natural color tones and causes a sense of unfamiliarity. Accordingly, the camera module (200) is configured to include an infrared blocking filter (220) that reflects light in the infrared region.

[0009] However, as the camera module (200) is embedded in a portable device, the camera module (200) becomes smaller and the configuration becomes thinner, and as the gap between the lens set (210), the infrared blocking filter (220), and the image element (230) becomes smaller, optical interference occurs, causing flare and ghosting phenomena. To solve this problem, there is a need to develop technology that includes an infrared blocking function in the protective cover glass (100) so that light in the infrared region is not incident into the camera module (200). The problem to be solved

[0010] The technical problem that the present invention aims to solve is to provide an infrared reflective cover glass that satisfies low-reflection optical characteristics and surface hardness characteristics while forming a thin film capable of reflecting light in the infrared region on a cover glass installed for protection of an imaging device.

[0011] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0012] The infrared reflective cover glass of the present invention for solving the above technical problem is a cover glass that protects an imaging device, comprising a transparent support substrate made of glass material, and a front thin film and a rear thin film in which a plurality of low-refractive-index layers or high-refractive-index layers are respectively formed in an alternating structure on the front side, which is the light incident side, and the rear side, which is the light exit side, with respect to the support substrate, and the cover glass can transmit visible light with a transmittance of 98.0% or more and reflect light in the infrared region.

[0013] In some embodiments of the present invention, the high refractive index layer is NbOx, TiOx, SiNx, SiOxNy (where x <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0014] In some embodiments of the present invention, the low refractive index layer may be formed as one of SiOx, SiOxNy (where x>y) or a nano-laminated thin film (SiOx+SiON).

[0015] In some embodiments of the present invention, the front thin film can reflect light in the infrared region.

[0016] In some embodiments of the present invention, the front thin film may be characterized by comprising a first high-refractive-index layer disposed furthest from the support substrate and a second high-refractive-index layer disposed thereafter, wherein the first high-refractive-index layer has a higher hardness than the second high-refractive-index layer.

[0017] In some embodiments of the present invention, the first high refractive index layers are formed in 2 to 5 layers, and the sum of the thicknesses of the formed first refractive index layers may be greater than 80 nm.

[0018] In some embodiments of the present invention, the first high-refractive-index layer is SiNx, SiOxNy (where x <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0019] In some embodiments of the present invention, the back film can reflect light in the infrared region.

[0020] In some embodiments of the present invention, the back film may be characterized by having a different infrared cutoff frequency. Effects of the invention

[0021] The infrared reflective cover glass according to the present invention includes a thin film capable of blocking infrared rays while having a high transmittance for visible light, so that light in the infrared region is not incident on the imaging device, thereby effectively eliminating flare and ghosting phenomena, and also increasing the durability of the applied product due to strong hardness characteristics. Brief explanation of the drawing

[0022] Figure 1 is a schematic diagram illustrating the structure of a cover glass and a camera. FIG. 2 is a drawing showing a cover glass according to a first embodiment of the present invention. FIG. 3 is a diagram showing the optical characteristics of the first embodiment of the present invention. FIG. 4 is a drawing showing a cover glass according to a second embodiment of the present invention. FIG. 5 is a diagram showing the optical characteristics of the second embodiment of the present invention. FIG. 6 is a drawing showing a cover glass according to a third embodiment of the present invention. FIG. 7 is a diagram showing the optical characteristics of the third embodiment of the present invention. FIG. 8 is a drawing showing a cover glass according to a fourth embodiment of the present invention. FIG. 9 is a diagram showing the optical characteristics of the fourth embodiment of the present invention. Figure 10 is a drawing showing an example for hardness reinforcement. Specific details for implementing the invention

[0023] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0024] "And / or" includes each of the mentioned items and all combinations of one or more.

[0025] The terms used herein are for describing embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, "comprising" and / or "comprising" does not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0026] Furthermore, throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly" or "electrically connected" with other members or elements interposed between them.

[0027] Additionally, throughout the specification, the description that each layer (film), region, pattern, or structure is formed "on" or "under" the substrate, each layer (film), region, pad, or pattern includes both direct formation and formation through another layer. The criteria for "on" or "under" each layer are described based on the drawings.

[0028] Furthermore, expressions such as 'first, second,' etc., are used solely to distinguish multiple compositions and do not limit the order or other characteristics between the compositions.

[0029] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0030] FIG. 2 is a drawing showing a cover glass according to a first embodiment of the present invention.

[0031] The cover glass (100) according to the present invention is a cover glass that protects an imaging device and comprises a transparent support substrate (101) made of glass material, and a front thin film and a rear thin film in which a plurality of low refractive index layers or high refractive index layers are formed in an alternating structure on the front side, which is the side of light incident, and the rear side, which is the side of light exit, respectively, based on the support substrate (101). The cover glass (100) can transmit visible light with a transmittance of 98.0% or more and reflect light in the infrared region.

[0032] Referring to FIG. 2, a cover glass (100) according to the first embodiment of the present invention may include a front film formed of a plurality of layers in an alternating structure of a low refractive index layer (110) and a first high refractive index layer (121) or a second high refractive index layer (122), and a rear film formed of a plurality of layers in an alternating structure of a low refractive index layer (110) and a high refractive index layer (120).

[0033] The refractive index of the high-index material that can be applied to the high-index layer (120) may have a range of 2.00≤n≤2.50 at λ=550nm, and the high-index layer (120) may be NbOx, TiOx, SiNx, SiOxNy (where x <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0034] The first high-refractive-index layer (121) is SiNx, SiOxNy (wherein x) which has relatively higher hardness performance among the high-refractive-index materials. <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0035] The second high-refractive-index layer (122) can be formed from one of NbOx or TiOx having a general hardness.

[0036] The refractive index of the low index material that can be applied to the low index layer (110) may have a range of 1.46≤n≤1.56 at λ=550nm, and the low index layer (110) may be formed as one of SiOx, SiOxNy (where x>y) or a nano-laminated thin film (SiOx+SiON).

[0037] The above Nano-Laminated thin film (SiOx+SiON) is a nano-laminate thin film in which SiOx and SiON are stacked in an alternating structure with a thickness of 2 nm to 10 nm.

[0038] The front thin film according to the present invention can reflect light in the infrared region.

[0039] The film thickness of the thin film formed on the front or back surface to reflect specific light can be formed with a thickness of λ / 4, where λ is the wavelength of the light to be reflected. By doing this, light reflected from all interfaces of the alternating layer becomes in the same phase when it reaches the incident surface, resulting in light enhancement; that is, the reflectivity increases near wavelength λ, allowing it to function as a light-reflecting film.

[0040] The front thin film of the cover glass according to the present invention may include a first high-refractive-index layer (121) disposed furthest from the support substrate (101) and a second high-refractive-index layer (122) disposed thereafter, and the first high-refractive-index layer (121) may be characterized by having a higher hardness than the second high-refractive-index layer (122).

[0041] The first high-refractive-index layer (121) is formed in 2 to 5 places, and the sum of the thicknesses of the formed first high-refractive-index layer (121) may be greater than 80 nm.

[0042] The above first high-refractive-index layer (121) is SiNx, SiOxNy with high hardness (where x <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0043] FIG. 10 is a drawing showing an example for hardness reinforcement according to the present invention.

[0044] Referring to FIG. 10, it can be seen that the surface hardness is improved depending on the number and thickness of the first high-refractive-index layer (121).

[0045] Bare glass is a support substrate (101) in its original state without a protective thin film formed, and its hardness is measured at 9.6 GPa.

[0046] Example 1 is a case where two first high-refractive-index layers (121) are formed with a total thickness of 82 nm, and the hardness is measured as 11.4 GPa.

[0047] Example 2 is a case where two first high-refractive-index layers (121) are formed with a total thickness of 75 nm, and the hardness is measured as 11.17 GPa.

[0048] Example 3 is a case where three first high-refractive-index layers (121) are formed with a total thickness of 120 nm, and the hardness is measured as 11.75 GPa.

[0049] Example 4 is a case where three first high-refractive-index layers (121) are formed with a total thickness of 230 nm, and the hardness is measured as 13.4 GPa.

[0050] Example 5 is a case where the first high refractive index layer (121) is formed with 5 layers and a total thickness of 250 nm, and the hardness is measured as 13.57 GPa.

[0051] Here, the above hardness measurement value is the average value obtained by measuring 16 points at a displacement of 100 to 200 nm with nanointenter hardness.

[0052] In this way, if the first high-refractive-index layer (121) with high hardness is formed at the position closest to the surface of the cover glass (100), the hardness of the cover glass (100) with the thin film formed can be increased, and the degree of hardness can be strengthened as the thickness of the formed first high-refractive-index layer (121) increases.

[0053] The cover glass (100) according to the first embodiment of the present invention shows an example in which three first high-refractive-index layers (121) are formed starting from the position closest to the surface of the cover glass (100), and the surface hardness can exhibit a performance of up to 12 GPa.

[0054] Referring to FIG. 2, the front thin film according to the first embodiment of the present invention is 1 from a position close to the support substrate (101). st The layer is a low refractive index layer (110), 2 nd The layer is formed as a second high-refractive-index layer (122), and the low-refractive-index layer (110) and the second high-refractive-index layer (122) are 16 th It can be formed by repeating up to the layer. Then 17 th The layer is a low refractive index layer (110), 18 th A layer is formed such that a first high-refractive-index layer (121) is formed, and the low-refractive-index layer (110) and the first high-refractive-index layer (121) are 22 ndThe layers are formed repeatedly, and finally, a low refractive index layer (110) can be formed.

[0055] In the above-mentioned front thin film, the refractive index of the low refractive index layer (110) can be formed to be 1.474, the refractive index of the first high refractive index layer (121) to be 2.041, and the refractive index of the second high refractive index layer to be 2.36.

[0056] At this time, the thickness of each refractive index layer of each front thin film is formed as shown in the table below, and the total thickness can be 1089 nm.

[0057] Table 1

[0058]

[0059] The rear thin film according to the first embodiment of the present invention is 1 from a position close to the support substrate (101). st The layer is a low refractive index layer (110), 2 nd The layer is formed as a high refractive index layer (120), and the low refractive index layer (110) and the high refractive index layer (120) are 6 th It can be formed by repeating up to the layer. Then 7 th A low refractive index layer (110) can be formed in the layer.

[0060] In the above-mentioned rear thin film, the refractive index of the low refractive index layer (110) can be formed to be 1.462, and the refractive index of the high refractive index layer (120) can be formed to be 2.316.

[0061] In addition, the thickness of each refractive index layer of each back-side thin film is formed as shown in the table below, and the total thickness can be 422 nm.

[0062] Table 2

[0063]

[0064] FIG. 3 is a diagram showing the optical characteristics of the first embodiment of the present invention, where (A) represents transmittance and (B) represents reflectance.

[0065] According to the first embodiment of the present invention, the front film may have both an anti-reflective film and an infrared reflective film formed thereon, and the rear film may have an anti-reflective film formed thereon.

[0066] Referring to FIG. 3 (A), the blue line represents a first embodiment of the present invention in which an anti-reflective film is formed on both the front and back surfaces, and the red line represents a comparative example in which an anti-reflective film is formed on only one of the two surfaces, that is, in which an anti-reflective film and an infrared reflective film are formed on one surface and no film is formed on the other surface.

[0067] In the case where a low-reflection film is formed on both the front and back surfaces, as shown by the blue line in (A) of Fig. 3, the average reflectance ≤1.3% and average transmittance ≥98.0% performance is shown in the visible light (λ=420~700nm) region.

[0068] When the anti-reflective thin film is formed on only one of the two surfaces, as shown by the blue line in (B) of Fig. 3, the cross-sectional average reflectance in the visible light (λ=420~700nm) region is ≤1.3% and the average transmittance is ≥94.5%.

[0069] Therefore, it can be confirmed that an excellent average transmittance is achieved when an anti-reflective thin film is formed on both the front and rear surfaces, as in the first embodiment of the present invention.

[0070] Referring to (B) of Fig. 3, the transmittance in the infrared region is ≤65% when λ=855nm, ≤25% when λ=1,000nm, and ≤50% when λ=1,200nm.

[0071] Referring to FIG. 1, since the infrared blocking filter (220) is still maintained inside the camera module (200), the cover glass (100) of the first embodiment according to the present invention can sufficiently perform the auxiliary function of the infrared blocking filter (220).

[0072] However, additional embodiments as follows may be applied so that the cover glass (100) according to the present invention can perform a more faithful infrared blocking function.

[0073] The rear thin film according to the present invention can be characterized by being able to reflect light in the infrared region and having a different cutoff frequency for infrared light.

[0074] The film thickness of the thin film formed on the front or back surface to reflect specific light can be formed with a thickness of λ / 4, where λ is the wavelength of the light to be reflected. By doing this, light reflected from all interfaces of the alternating layer becomes in the same phase when it reaches the incident surface, resulting in light enhancement; that is, the reflectivity increases near wavelength λ, allowing it to function as a light-reflecting film.

[0075] FIG. 4 is a drawing showing a cover glass according to a second embodiment of the present invention.

[0076] The cover glass (100) according to the present invention is a cover glass that protects an imaging device and comprises a transparent support substrate (101) made of glass material, and a front thin film and a rear thin film in which a plurality of low refractive index layers or high refractive index layers are formed in an alternating structure on the front side, which is the side of light incident, and the rear side, which is the side of light exit, respectively, based on the support substrate (101). The cover glass (100) can transmit visible light with a transmittance of 98.0% or more and reflect light in the infrared region.

[0077] Referring to FIG. 4, a cover glass (100) according to a second embodiment of the present invention may include a front film formed of a plurality of layers in an alternating structure of a low refractive index layer (110) and a first high refractive index layer (121) or a second high refractive index layer (122), and a rear film formed of a plurality of layers in an alternating structure of a low refractive index layer (110) and a high refractive index layer (120).

[0078] The refractive index of the high-index material that can be applied to the high-index layer (120) may have a range of 2.00≤n≤2.50 at λ=550nm, and the high-index layer (120) may be NbOx, TiOx, SiNx, SiOxNy (where x <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0079] The first high-refractive-index layer (121) is SiNx, SiOxNy (wherein x) which has relatively higher hardness performance among the high-refractive-index materials. <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0080] The second high-refractive-index layer (122) can be formed from one of NbOx or TiOx having a general hardness.

[0081] The refractive index of the low index material that can be applied to the low index layer (110) may have a range of 1.46≤n≤1.56 at λ=550nm, and the low index layer (110) may be formed as one of SiOx, SiOxNy (where x>y) or a nano-laminated thin film (SiOx+SiON).

[0082] The above Nano-Laminated thin film (SiOx+SiON) is a nano-laminate thin film in which SiOx and SiON are stacked in an alternating structure with a thickness of 2 nm to 10 nm.

[0083] The front film according to the second embodiment of the present invention is identical to the first embodiment according to the present invention, so the description is omitted.

[0084] According to the second embodiment of the present invention, the back film is formed such that, starting from a position close to the support substrate (101), the 1st layer is formed as a high refractive index layer (120) and the 2nd layer is formed as a low refractive index layer (110), and the high refractive index layer (120) and the low refractive index layer (110) can be repeated up to the 20th layer.

[0085] In the above-mentioned rear thin film, the refractive index of the low refractive index layer (110) can be formed to be 1.451, and the refractive index of the high refractive index layer (120) can be formed to be 2.378.

[0086] In addition, the thickness of each refractive index layer of the back film is formed as shown in the table below, and the total thickness can be 2576 nm.

[0087] Table 3

[0088]

[0089] FIG. 5 is a diagram showing the optical characteristics of the second embodiment of the present invention, where (A) represents transmittance and (B) represents reflectance.

[0090] According to a second embodiment of the present invention, an anti-reflective film and an infrared reflective film can be simultaneously formed on both the front film and the rear film.

[0091] Referring to FIG. 5, it can be seen that the reflection performance of light in the infrared region is improved compared to the reflection performance of the first embodiment according to the present invention.

[0092] In order to effectively block the infrared region, the blocking range can be expanded by having each region perform a blocking role without overlapping the blocking ranges of the optical designs of the front thin film and the back thin film.

[0093] In other words, areas other than those blocked from the front can be blocked from the rear.

[0094] By forming a back film, the second embodiment can optionally block infrared wavelengths of 950 nm or greater with a transmittance of 0.1% or less.

[0095] In this way, the back film can reflect light in the infrared region, and the infrared cutoff frequency can be formed differently.

[0096] FIG. 6 is a drawing showing a cover glass according to a third embodiment of the present invention.

[0097] The cover glass (100) according to the present invention is a cover glass that protects an imaging device and comprises a transparent support substrate (101) made of glass material, and a front thin film and a rear thin film in which a plurality of low refractive index layers or high refractive index layers are formed in an alternating structure on the front side, which is the side of light incident, and the rear side, which is the side of light exit, respectively, based on the support substrate (101). The cover glass (100) can transmit visible light with a transmittance of 98.0% or more and reflect light in the infrared region.

[0098] Referring to FIG. 6, a cover glass (100) according to a third embodiment of the present invention may include a front film formed of a plurality of layers in an alternating structure of a low refractive index layer (110) and a first high refractive index layer (121) or a second high refractive index layer (122), and a rear film formed of a plurality of layers in an alternating structure of a low refractive index layer (110) and a high refractive index layer (120).

[0099] The refractive index of the high-index material that can be applied to the high-index layer (120) may have a range of 2.00≤n≤2.50 at λ=550nm, and the high-index layer (120) may be NbOx, TiOx, SiNx, SiOxNy (where x <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0100] The first high-refractive-index layer (121) is SiNx, SiOxNy (wherein x) which has relatively higher hardness performance among the high-refractive-index materials. <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0101] The second high-refractive-index layer (122) can be formed from one of NbOx or TiOx having a general hardness.

[0102] The refractive index of the low index material that can be applied to the low index layer (110) may have a range of 1.46≤n≤1.56 at λ=550nm, and the low index layer (110) may be formed as one of SiOx, SiOxNy (where x>y) or a nano-laminated thin film (SiOx+SiON).

[0103] The above Nano-Laminated thin film (SiOx+SiON) is a nano-laminate thin film in which SiOx and SiON are stacked in an alternating structure with a thickness of 2 nm to 10 nm.

[0104] The front film according to the third embodiment of the present invention is identical to the first embodiment according to the present invention, so the description is omitted.

[0105] According to the third embodiment of the present invention, the back film is formed such that, starting from a position close to the support substrate (101), the 1st layer is formed as a high refractive index layer (120) and the 2nd layer as a low refractive index layer (110), and the high refractive index layer (120) and the low refractive index layer (110) are repeated up to the 26th layer.

[0106] In the above-mentioned rear thin film, the refractive index of the low refractive index layer (110) can be formed to be 1.463, and the refractive index of the high refractive index layer (120) can be formed to be 2.358.

[0107] In addition, the thickness of each refractive index layer of each back-side thin film is formed as shown in the table below, and the total thickness can be 2927 nm.

[0108] Table 4

[0109]

[0110] FIG. 7 is a diagram showing the optical characteristics of the third embodiment of the present invention, where (A) represents transmittance and (B) represents reflectance.

[0111] According to the third embodiment of the present invention, an anti-reflective film and an infrared reflective film can be simultaneously formed on both the front film and the rear film.

[0112] Referring to FIG. 7, it can be seen that the reflection performance of light in the infrared region is improved compared to the reflection performance of the first embodiment according to the present invention.

[0113] In order to effectively block the infrared region, the blocking range can be expanded by having each region perform a blocking role without overlapping the blocking ranges of the optical designs of the front thin film and the back thin film.

[0114] In other words, areas other than those blocked from the front can be blocked from the rear.

[0115] By forming a back film, the third embodiment can optionally block infrared wavelengths of 780 nm or more and 970 nm or less with a transmittance of 0.1% or less.

[0116] In this way, the back film can reflect light in the infrared region, and the infrared cutoff frequency can be formed differently.

[0117] FIG. 8 is a drawing showing a cover glass according to a fourth embodiment of the present invention.

[0118] The cover glass (100) according to the present invention is a cover glass that protects an imaging device and comprises a transparent support substrate (101) made of glass material, and a front thin film and a rear thin film in which a plurality of low refractive index layers or high refractive index layers are formed in an alternating structure on the front side, which is the side of light incident, and the rear side, which is the side of light exit, respectively, based on the support substrate (101). The cover glass (100) can transmit visible light with a transmittance of 98.0% or more and reflect light in the infrared region.

[0119] Referring to FIG. 8, a cover glass (100) according to a third embodiment of the present invention may include a front film formed of a plurality of layers in an alternating structure of a low refractive index layer (110) and a first high refractive index layer (121) or a second high refractive index layer (122), and a rear film formed of a plurality of layers in an alternating structure of a low refractive index layer (110) and a high refractive index layer (120).

[0120] The refractive index of the high-index material that can be applied to the high-index layer (120) may have a range of 2.00≤n≤2.50 at λ=550nm, and the high-index layer (120) may be NbOx, TiOx, SiNx, SiOxNy (where x <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0121] The first high-refractive-index layer (121) is SiNx, SiOxNy (wherein x) which has relatively higher hardness performance among the high-refractive-index materials. <y), AlNx, SiC, SiOxCy 중 하나로 형성될 수 있다.

[0122] The second high-refractive-index layer (122) can be formed from one of NbOx or TiOx having a general hardness.

[0123] The refractive index of the low index material that can be applied to the low index layer (110) may have a range of 1.46≤n≤1.56 at λ=550nm, and the low index layer (110) may be formed as one of SiOx, SiOxNy (where x>y) or a nano-laminated thin film (SiOx+SiON).

[0124] The above Nano-Laminated thin film (SiOx+SiON) is a nano-laminate thin film in which SiOx and SiON are stacked in an alternating structure with a thickness of 2 nm to 10 nm.

[0125] The front film according to the fourth embodiment of the present invention is identical to the first embodiment according to the present invention, so the description is omitted.

[0126] According to the fourth embodiment of the present invention, the back film is formed such that, starting from a position close to the support substrate (101), the 1st layer is formed as a high refractive index layer (120) and the 2nd layer is formed as a low refractive index layer (110), and the high refractive index layer (120) and the low refractive index layer (110) can be repeated up to the 36th layer.

[0127] In the above rear thin film, the refractive index of the low refractive index layer (110) can be formed to be 1.474, and the refractive index of the high refractive index layer (120) can be formed to be 2.503.

[0128] In addition, the thickness of each refractive index layer of each back film is formed as shown in the table below, so the total thickness can be 4421 nm.

[0129] Table 5

[0130]

[0131] FIG. 9 is a diagram showing the optical characteristics of the fourth embodiment of the present invention, where (A) represents transmittance and (B) represents reflectance.

[0132] According to the fourth embodiment of the present invention, an anti-reflective film and an infrared reflective film can be simultaneously formed on both the front film and the rear film.

[0133] Referring to FIG. 9, it can be seen that the reflection performance of light in the infrared region is improved compared to the reflection performance of the first embodiment according to the present invention.

[0134] In order to effectively block the infrared region, the blocking range can be expanded by having each region perform a blocking role without overlapping the blocking ranges of the optical designs of the front thin film and the back thin film.

[0135] In other words, areas other than those blocked from the front can be blocked from the rear.

[0136] By forming a back film, the fourth embodiment can optionally block infrared wavelengths of 750 nm or more and 1150 nm or less with a transmittance of 0.1% or less.

[0137] In this way, the back film can reflect light in the infrared region, and the infrared cutoff frequency can be formed differently.

[0138] As confirmed in the various embodiments above, the present invention can be applied to meet the specifications required by each device by varying the infrared cutoff frequency.

[0139] In addition, it can also be used as a protective cover for electronic products that are mainly used outdoors and have a high frequency and intensity of exposure to infrared rays, even in devices that do not include an imaging element.

[0140] The cover glass (100) according to an embodiment of the present invention may further include a water-repellent film (130).

[0141] The above-mentioned water-repellent film (130) can have an anti-fingerprint function as a film formed at the farthest point from the front film on the cover glass (100) to the support substrate (101).

[0142] The multilayer thin film formed on the cover glass (100) can be formed by a PVD or PECVD thin film coating on a support substrate (101).

[0143] PVD (Physical Vapor Deposition) refers to a physical vapor deposition method. When an inert gas such as argon or helium is filled into a vacuum container and a high voltage is applied to the coating material to discharge it, the ionized inert gas collides with the coating material, and at this time, ions from the coating material are ejected, causing a thin film to be deposited on the surface of the support substrate (101) or the previous coating layer.

[0144] PECVD (Plasma Enhanced Chemical Vapor Deposition) is a plasma chemical vapor deposition method. It utilizes a reaction in which gases decomposed by plasma adhere to the surface of a support substrate (101) or a previous coating layer.

[0145] Although the present invention has been described above, those skilled in the art will recognize that the invention may be implemented in other forms while maintaining the technical concept and essential features of the invention.

[0146] The scope of the rights of the present invention shall be determined primarily by the patent claims; however, configurations directly derived from the descriptions in the patent claims, as well as all modifications or variations derived from configurations equivalent thereto, shall be interpreted as being included within the scope of the rights of the present invention. Explanation of the symbols

[0147] 100 : Cover glass 101 : Support substrate 110: Low refractive index layer 120: High refractive index layer 121: First high-refractive-index layer 122 : Second high-refractive-index layer 130: Water-repellent film 200 : Camera module 210 : Lens set 220: Infrared blocking filter 230 : Image sensor

Claims

Claim 1 An infrared reflective cover glass for protecting an imaging device, comprising: a transparent support substrate made of glass material; a front thin film and a rear thin film, wherein a plurality of low-refractive-index layers or high-refractive-index layers are respectively formed in an alternating structure on the front side, which is the incident side of light, and the rear side, which is the exit side of light, with respect to the support substrate, wherein the cover glass transmits visible light with a transmittance of 98.0% or more and reflects light in the infrared region by the front thin film or the rear thin film, wherein the front thin film comprises a first high-refractive-index layer disposed furthest from the support substrate and a second high-refractive-index layer disposed thereafter, and wherein the first high-refractive-index layer has a higher hardness than the second high-refractive-index layer. Claim 2 In claim 1, the high refractive index layer is NbOx, TiOx, SiNx, SiOxNy (wherein x <y), AlNx, SiC, SiOxCy 중 하나로 형성되는, 적외선 반사 커버 글라스. Claim 3 In claim 1, the infrared reflective cover glass, wherein the low refractive index layer is formed from one of SiOx, SiOxNy (where x>y) or a nano-laminated thin film (SiOx+SiON). Claim 4 delete Claim 5 delete Claim 6 In claim 1, the infrared reflective cover glass, wherein the first high-refractive-index layers are formed in 2 to 5 layers, and the sum of the thicknesses of the formed first refractive-index layers is greater than 80 nm. Claim 7 In claim 1, the first high-refractive-index layer is SiNx, SiOxNy (wherein x <y), AlNx, SiC, SiOxCy 중 하나로 형성되는, 적외선 반사 커버 글라스. Claim 8 delete

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