TW202224928A - Antireflection-film-equipped glass covering - Google Patents

Abstract

The present invention pertains to an antireflection-film-equipped glass covering that is a glass covering provided with an antireflection film. The antireflection film is formed by alternately layering high refractive index layers and low refractive index layers. The outermost layer of the antireflection film is a low refractive index layer, and the total number of layers of the high refractive index layers and low refractive index layers is five or more. The thickness of the low refractive index layer which is the third layer from the outermost side of the antireflection film is no more than 35nm, and the thickness of the low refractive index layer which is the fifth layer from the outermost side is no more than 15nm.

Description

Cover glass with anti-reflection film

The present invention relates to a cover glass with an anti-reflection film.

In-vehicle information equipment, such as car navigation systems and audio systems, and portable communication equipment are equipped with display devices. In the display device, in order to protect the display panel from external impact, a protective cover such as a cover glass is provided. On the surface of the protective cover, in order to reduce the reflection of external light, an anti-reflection film is sometimes provided.

In addition, on the surface of the protective cover on the display panel side, for example, the light shielding layer is provided in a frame shape. In addition to being beautiful, the light-shielding layer also has the function of shielding the wiring on the side of the display panel or shielding the illumination light of the backlight, so as to prevent the illumination light from leaking from the surrounding of the display panel.

In such a display device, a sign, or the like, for example, as shown in FIG. 1 , an infrared sensor 4 is incorporated in the display area or its vicinity. The purpose is to use infrared rays for communication or object detection, specifically, for monitoring drivers or for fingerprint detection, touch sensing, gesture sensing, and the like. However, due to the infrared transmittance of the protective cover, specifically the infrared transmittance of the cover glass 2 provided with the anti-reflection film 1, the transmittances of the sensing light and the signal light used for the infrared sensor 4 are reduced, cause the sensor to malfunction or fail.

Therefore, there is known a structure in which an infrared sensor can be provided on the back surface of the light-shielding layer by forming an opening in a part of the light-shielding layer in the shape of a frame to provide an infrared-transmitting layer, which is a region through which infrared light can transmit. side, and the infrared transmission layer is made inconspicuous (Patent Documents 1 and 2). [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2017-49469 [Patent Document 2] Japanese Patent No. 5392641

[Problems to be Solved by Invention]

However, as shown in FIG. 1 , when the cover glass 2 is punched to form an opening, even if it is a part of the frame-shaped light-shielding layer, the design property is impaired from a design viewpoint. In addition, there is also concern that the cost will increase due to the drilling process.

In this regard, an object of the present invention is to provide a cover glass with an antireflection film, which can maintain the suppression of visible light reflectance without forming an opening, and can also suppress infrared light reflectance and has high infrared light transmittance. [Technical means to solve problems]

The inventors of the present invention found that the above-mentioned problems can be solved by setting the thickness of the low-refractive-index layer at a specific position among the high-refractive-index layer and the low-refractive-index layer constituting the antireflection film to a thickness below a fixed value, and completed the this invention.

That is, one aspect of the present invention is as follows. [1] A cover glass with an anti-reflection film, which is a cover glass with an anti-reflection film, wherein the anti-reflection film is formed by alternately laminating high-refractive-index layers and low-refractive-index layers, and the outermost layer is a low-refractive-index layer , the total number of layers of the high-refractive-index layer and the low-refractive-index layer is 5 or more, the thickness of the low-refractive-index layer located in the third layer from the outermost layer is 35 nm or less, and the thickness of the low-refractive index layer located in the third layer from the outermost layer is 35 nm or less, The thickness of the low refractive index layer of the fifth layer is 15 nm or less. [2] The cover glass with an antireflection film according to the above [1], wherein the reflectance of visible light at a wavelength of 550 nm of the antireflection film is 0.4% or less, and the reflectance of infrared light at a wavelength of 950 nm is 5% or less . [3] The cover glass with antireflection film according to the above [1] or [2], wherein the high refractive index layer has a refractive index of 1.9 or more at a wavelength of 550 nm, and the low refractive index layer has a refractive index of 550 nm at a wavelength of 550 nm. The refractive index is 1.6 or less. [4] The cover glass with an antireflection film according to any one of the above-mentioned [1] to [3], wherein the high-refractive-index material constituting the above-mentioned high-refractive index layer comprises a material selected from the group consisting of Mo, W, Mg, Si, and Nb. , at least one oxide of the group consisting of Ti, Zr, Ta, Al, Sn and In. [5] The cover glass with an antireflection film according to any one of the above [1] to [4], wherein the low refractive index material constituting the low refractive index layer is selected from SiO ₂ , MgF ₂ , Si and Sn At least one of the group consisting of the material of the mixed oxide, the material of the mixed oxide of Si and Zr, and the material of the mixed oxide of Si and Al. [6] The cover glass with an antireflection film according to any one of the above [1] to [5], which is used together with an infrared sensor, and does not have an opening at the portion where the incoming and outgoing light of the infrared sensor is transmitted. . [7] A display device including an infrared sensor and the cover glass with an antireflection film according to any one of the above [1] to [6]. [Effect of invention]

According to the present invention, it is possible to obtain a cover glass with an antireflection film that suppresses not only the reflectance of visible light but also the reflectance of infrared light. By applying such a cover glass with an antireflection film to a display device, it is possible to provide an in-vehicle display device capable of improving infrared light transmittance, maintaining excellent visibility, and preventing malfunction of an infrared sensor, etc. Mobile display devices, signage, etc.

Hereinafter, although this invention is demonstrated in detail, this invention is not limited to the following embodiment, It can change arbitrarily in the range which does not deviate from the summary of this invention, and can implement. In addition, "-" which shows a numerical range is used in the meaning which includes the numerical value described before and after it as a lower limit and an upper limit.

<Cover glass with anti-reflection film> The cover glass with an antireflection film according to this embodiment is provided with an antireflection film on the surface of the cover glass. As shown in FIG. 3 , the antireflection film 1 is formed by alternately laminating high-refractive-index layers and low-refractive-index layers, and its outermost layer is a low-refractive-index layer 11 . The total number of high-refractive-index layers and low-refractive-index layers is 5 or more, and the thickness of the low-refractive index layer 12 is 35 nm or less, and the thickness of the low-refractive index layer 12 is 35 nm or less, and it is the fifth layer from the outermost layer. The thickness of the low refractive index layer 13 of the layer is 15 nm or less.

[Anti-reflection film] In the cover glass with anti-reflection film, the anti-reflection film 1 is arranged on the surface of the cover glass 2 . The antireflection film is formed by alternately laminating high-refractive-index layers and low-refractive-index layers. The high-refractive index layer and the low-refractive index layer may be dielectric layers having different refractive indices from each other. That is, the level of the refractive index is not determined by the absolute value, but refers to the relative height and lowness with respect to the refractive index of the adjacent layer when the layers are stacked.

Reflection of visible light is suppressed by laminating high-refractive-index layers and low-refractive-index layers having different refractive indices. Furthermore, the outermost layer among the high-refractive-index layers and the low-refractive-index layers to be laminated is made the low-refractive-index layer 11 from the viewpoint of relatively easy production of an anti-reflection film with low visible light reflectance. Furthermore, the visible light reflectance in this specification refers to the reflectance of light with a wavelength of 550 nm.

Furthermore, by reducing the thicknesses of the low refractive index layers 12 and 13 located at the third and fifth layers from the outermost layer, not only the reflectance of visible light but also the reflectance of infrared light can be suppressed. In addition, the low-refractive index layers 12 and 13 located at the third and fifth layers from the outermost layer correspond to only the low-refractive index layer as the object and the outermost low-refractive index layer as the first layer. the second low refractive index layer and the third low refractive index layer. In addition, the infrared light reflectance in this specification refers to the reflectance of light with a wavelength of 950 nm.

The specific thickness of the low refractive index layer 12 located in the third layer from the outermost layer is 35 nm or less. Moreover, the thickness of the low-refractive-index layer 13 located in the fifth layer from the outermost layer is 15 nm or less. In this way, the reflectance of infrared light can be significantly reduced, thereby increasing the transmittance of infrared light. Therefore, the loss of the sensing light and the signal light of the infrared sensor is less, and the malfunction or error of the sensor can be suppressed.

The thickness of the low refractive index layer 12 located in the third layer from the outermost layer may be 35 nm or less, preferably 25 nm or less, and more preferably 15 nm or less. The thickness of the low refractive index layer 13 located in the fifth layer from the outermost layer may be 15 nm or less, and preferably 10 nm or less. In addition, the lower limit is not particularly limited, but it is usually preferable that the thickness of the low-refractive index layers located in the third layer and the fifth layer from the outermost layer is 5 nm or more.

The thickness of the low-refractive-index layer 12 located in the third layer from the outermost layer and the low-refractive-index layer 13 located in the fifth layer from the outermost layer may be the same or different.

The thickness of the low-refractive-index layers other than the low-refractive-index layers 12 and 13 of the third and fifth layers from the outermost layer is not particularly limited. From the viewpoint of suppressing reflectance, the outermost low refractive index layer 11 is preferably thicker than the third and fifth low refractive index layers 12 and 13, more preferably 75 nm or more, and more preferably 80 nm above, and more preferably 85 nm or more. Furthermore, from the aspect of the design of the display device, the thickness of the outermost low refractive index layer 11 is preferably 110 nm or less, more preferably 100 nm or less.

The thickness of the high refractive index layer in the antireflection film is not particularly limited. When the cover glass with the anti-reflection film is applied to a display device, in terms of the design of the device, the high-refractive index layer 21 is located in the second layer from the outermost layer, that is, the high-refractive index layer is located closest to the high-refractive index layer. The high refractive index layer on the outermost layer side is preferably 40 nm or less, more preferably 35 nm or less, and still more preferably 30 nm or less. Moreover, from the viewpoint of lowering the reflectance, the high refractive index layer 21 in the second layer is preferably 10 nm or more, more preferably 15 nm or more, and still more preferably 20 nm or more.

From the viewpoint of reducing reflectance, the thickness of the high refractive index layers after the fourth layer from the outermost layer of the antireflection film 1 is preferably 2 nm or more, more preferably 3 nm or more, and more preferably 4 nm above. In addition, from the viewpoint of productivity, the thickness of the high refractive index layers after the fourth layer from the outermost layer is preferably 25 nm or less, more preferably 20 nm or less, and still more preferably 15 nm or less.

The total number of layers of the high-refractive index layer and the low-refractive index layer constituting the antireflection film 1 may be 5 or more, but from the viewpoint of reflectivity, it is preferably 8 or more, more preferably 10 or more. Moreover, from the viewpoint of productivity, the total number of layers is preferably 12 or less, and more preferably 11 or less.

In the antireflection film, the layer in contact with the cover glass may be a low-refractive index layer or a high-refractive-index layer, but from the viewpoint of adhesiveness, a low-refractive index layer is preferred. In addition, in FIG. 3, the dotted line "..." is shown between the high refractive index layer 23 located in the sixth layer from the outermost layer, and the low refractive index layer 14 in contact with the cover glass. The dotted line is shown between the high-refractive-index layer 23 located at the sixth layer from the outermost layer and the low-refractive-index layer 14 in contact with the cover glass, and any number of low-refractive-index layers and high-refractive-index layers can be alternately laminated. rate layer.

The total thickness of the high refractive index layer and the low refractive index layer, that is, the thickness of the antireflection film 1 is not particularly limited, but from the viewpoint of productivity, it is preferably 550 nm or less, more preferably 350 nm or less, and still more preferably below 290 nm.

From the viewpoint of lowering the reflectance, the refractive index of the high refractive index layer at a wavelength of 550 nm is preferably 1.9 or more, more preferably 2.2 or more. In addition, the upper limit of the refractive index is not particularly limited, but is usually 2.5 or less.

From the viewpoint of lowering the reflectance, the refractive index of the low refractive index layer at a wavelength of 550 nm is preferably 1.6 or less, more preferably 1.5 or less. In addition, the lower limit of the refractive index is not particularly limited, but is usually 1.35 or more.

The high-refractive index layer and the low-refractive index layer preferably contain at least one oxide, nitrogen selected from the group consisting of Mo, W, Mg, Si, Nb, Ti, Zr, Ta, Al, Sn, and In compound, or fluoride. By using the above oxides, nitrides or fluorides, the absorption energy of the high-refractive index layer and the low-refractive index layer in the entire visible wavelength region is reduced, and the reflectance of visible light and infrared light can be suppressed to be low, so better.

In order to achieve a desired refractive index, each material constituting the high refractive index layer and the low refractive index layer is appropriately selected from the above-mentioned oxides, nitrides or fluorides. Each of the high refractive index layer and the low refractive index layer may be composed of only one of the above oxides, nitrides and fluorides, or may include two or more. In addition, the high-refractive-index layer and the low-refractive-index layer each have a plurality of layers, and these layers may be composed of the same material or may be composed of different materials. That is, the high-refractive-index layer and the low-refractive-index layer having a plurality of layers may have different refractive indices, respectively.

Among the above materials, the high refractive index material constituting the high refractive index layer preferably contains at least one selected from the group consisting of Mo, W, Mg, Si, Nb, Ti, Zr, Ta, Al, Sn and In the above oxides.

Further, among the above-mentioned materials, the low-refractive-index material constituting the low-refractive-index layer is preferably selected from SiO ₂ , MgF ₂ , materials containing mixed oxides of Si and Sn, materials containing mixed oxides of Si and Zr, and At least one of the group consisting of materials containing a mixed oxide of Si and Al, more preferably SiO ₂ , and more preferably mainly containing SiO ₂ . In addition, in this specification, "mainly contained" means that it occupies 20 mass % or more in the component which comprises this layer.

The anti-reflection film may be directly formed on the surface of the cover glass, but an anti-reflection film may also be formed on the surface of the cover glass by forming an anti-reflection film on the surface of the film and attaching the film to the cover glass. The film is not particularly limited as long as it is transparent. For example, a film called a clear hard coat (CHC) film or the like can be generally used.

When an antireflection film is formed on the surface of the film, in order to prevent gas components from the film, etc., a silicon nitride (SiN) layer may be formed on the surface of the film, and then the antireflection film may be formed. Although the thickness of this layer is not specifically limited, For example, 5-30 nm is mentioned.

The adhesive layer at the time of bonding the film to the cover glass is not particularly limited, and for example, an acrylic-based optical adhesive, a silicone-based adhesive, a urethane-based adhesive, and the like can be used. Using the adhesive layer, the bonding is performed so that the film is on the cover glass side, that is, the antireflection film is bonded on the outside. The thickness of the adhesive layer is not particularly limited, and for example, 5 to 100 μm can be mentioned.

Such an antireflection film separated by a film may be formed on both sides of the cover glass. Moreover, an antireflection film may be formed directly on one surface of the cover glass, and an antireflection film may be formed on the other surface via the film.

Moreover, an IR (infrared) transmission ink may be apply|coated to the surface of a cover glass or a film, and an antireflection film may be formed on this IR (infrared) transmission ink. IR-transmitting ink is preferable because it can improve designability. As the IR-transmitting ink, previously known inks can be used.

When the cover glass with the anti-reflection film is used for a display device, from the viewpoint of visibility of the display device, the visible light reflectance of the anti-reflection film at a wavelength of 550 nm is preferably 1% or less, more preferably 0.4% or less , and more preferably 0.3% or less. The lower the visible light reflectance, the better, but is usually 0.05% or more. In addition, the visible light reflectance at a wavelength of 550 nm and the infrared light reflectance at a wavelength of 950 nm in this specification are values measured by a spectrophotometer (manufactured by Shimadzu Corporation, trade name: Solid Spec-3700). In addition, the visible light transmittance at the wavelength of 550 nm and the infrared light transmittance at the wavelength of 950 nm described below are both vertical incidence transmittances, which are also made by a spectrophotometer (manufactured by Shimadzu Corporation, trade name: Solid Spec-3700). ) measured value.

When a cover glass with an antireflection film is used together with an infrared sensor, from the viewpoint of preventing malfunction of the infrared sensor, the infrared reflectance of the antireflection film at a wavelength of 950 nm is preferably 5% or less , more preferably 3% or less, still more preferably 1% or less. The lower the infrared light reflectivity, the better, but it is usually 0.5% or more.

The color tone of the cover glass with the anti-reflection film can be based on the color index. The color index is a value obtained as a ^* value and b ^* value, which are color indexes specified in JIS Z 8729:2004, from the reflection spectrum of the spectral reflectance obtained in the above-mentioned reflectance measurement.

The antireflection film can be formed on the main surface of the cover glass by known film-forming methods such as sputtering, ion beam sputtering, vacuum deposition, plasma-assisted ion-assisted deposition, and ion plating. That is, the high-refractive-index layer and the low-refractive-index layer constituting the antireflection film are formed on the main surface of the cover glass in this lamination order. The sputtering method includes magnetron sputtering, pulse sputtering, AC (Alternating Current) sputtering, digital sputtering, and the like. Among the above-mentioned film forming methods, for example, the magnetron sputtering method is a method in which a magnet is provided on the backside of the material to be a high-refractive index layer or a low-refractive index layer to generate a magnetic field, and gas ion atoms collide with the front surface of the material to generate a magnetic field. It is knocked out, thereby sputtering into a film with a thickness of several nm. A continuous film of oxides or nitrides of metals can be formed as materials.

The digital sputtering method is different from the ordinary magnetron sputtering method. First, a metal thin film is formed by sputtering, and then oxidized by irradiating oxygen plasma, oxygen ions or oxygen radicals. The steps of forming and oxidizing the metal electrode film are repeatedly performed in the same chamber to form a film that will become a high-refractive index layer or a low-refractive index layer. In this case, since the molecular film formed on the substrate is metal, it is presumed that it has ductility compared with the case where the film is formed with a metal oxide. Therefore, even at the same energy, it is considered that the relocation of the film-forming molecules is facilitated, and as a result, a dense and smooth film can be realized.

The antireflection film may be formed on at least one main surface of the cover glass. Moreover, when using the cover glass with an antireflection film for a display device, it is preferable to form an antireflection film on the main surface of the surface side exposed to the outside of the cover glass. If necessary, an anti-reflection film can also be formed on both main surfaces of the cover glass. In addition, the surface side exposed to the outside of a cover glass means the surface side opposite to the surface side which has an infrared sensor or a display part in a display apparatus.

[cover glass] The refractive index of the cover glass provided with the antireflection film is preferably 1.4 or more and 1.7 or less. This is because, when a cover glass with an antireflection film is used for a display device, when a display or a touch panel is optically bonded, reflection on the bonding surface can be sufficiently suppressed. Glasses having various compositions can be used for the cover glass. For example, it is preferable to contain sodium, and it is more preferable that it is a composition which can be shaped and strengthened by chemical strengthening treatment. Further, specific examples thereof include aluminosilicate glass, soda lime glass, borosilicate glass, lead glass, alkali barium glass, aluminoborosilicate glass, and the like.

The thickness of the cover glass is not particularly limited, but when the chemical strengthening treatment is performed, in order to effectively perform the chemical strengthening treatment, it is usually preferably 5 mm or less, more preferably 3 mm or less. The lower limit is not particularly limited, but is preferably 0.5 mm or more in terms of strength. Moreover, it is preferable to use the chemically strengthened glass which improved the intensity|strength by chemical strengthening.

When the cover glass with anti-reflection film is used together with an infrared sensor, from the viewpoint of preventing malfunction of the infrared sensor, the cover glass with anti-reflection film has better infrared transmittance at a wavelength of 950 nm It is 85% or more, more preferably 88% or more, still more preferably 90% or more, and the higher the better.

The visible light transmittance of the cover glass with the anti-reflection film at a wavelength of 550 nm is preferably 90% or more, more preferably 92% or more, the higher the better.

When the anti-glare treatment is performed on the cover glass, the chemical strengthening treatment is preferably performed after the anti-glare treatment and before the anti-reflection film is formed.

The anti-glare treatment is preferably performed on the main surface of the cover glass on the side having the antireflection film. The anti-glare treatment method is not particularly limited, and a method in which a surface treatment is applied to the main surface of the glass to form desired irregularities can be used. Specifically, a method of chemically treating the main surface of the cover glass, for example, a method of performing a frosting treatment can be mentioned. In the frosting treatment, for example, the cover glass, which is the object to be treated, is dipped in a mixed solution of hydrogen fluoride and ammonium fluoride to perform chemical surface treatment on the immersed surface. In addition to chemical treatment methods, for example, physical treatment methods such as sandblasting in which crystalline silicon dioxide powder, silicon carbide powder, etc. are blown onto the surface of the glass substrate by pressurized air, or by water treatment, can also be used The brush of high quality silicon dioxide powder, silicon carbide powder, etc. is wet and then rubbed.

<Display device> The cover glass with the anti-reflection film of this embodiment is preferably used together with the infrared sensor 4 as shown in FIG. 2 . Moreover, the display device 10 of this embodiment is provided with the infrared sensor 4, and the cover glass 2 provided with the antireflection film 1. The cover glass 2 provided with the anti-reflection film 1 here can be the same as the cover glass with an anti-reflection film described in the above-mentioned <cover glass with an anti-reflection film>, and the preferred form is also the same. The infrared sensor 4 is not particularly limited as long as it includes a light source for emitting sensing light and a camera for detecting signal light for monitoring and the like. When the cover glass with anti-reflection film is used together with the infrared sensor, since the infrared light transmittance of the cover glass with anti-reflection film is high, it is not necessary to install the infrared sensor at the part where the incoming and outgoing light is transmitted. The opening shown in Figure 1. That is, it is preferable that the cover glass with an antireflection film does not have the said opening part from a viewpoint of designability or cost. A printed layer 5 may also be formed between the infrared sensor 4 and the cover glass 2 . The printed layer 5 may be a shielding layer for shielding wiring members and the like arranged on the peripheral edge of the cover glass 2 , and may also be a decorative layer for improving the designability of the display device 10 . In the case of having a printed layer or a decorative layer, in order to maintain the transmittance of the incoming and outgoing light of the infrared sensor, that is, the transmittance of infrared light in the light-transmitting region, it is preferable not to have the printed layer 5 in the light-transmitting region. Alternatively, it is preferable to include an IR-transmitting ink layer 6 instead of the printing layer 5 . The IR-transmitting ink layer is a layer formed by using ink with high infrared light transmittance, and is preferably formed in the region where the incoming and outgoing light passes through the sensing light and signal light of the infrared sensor.

The display panel in the display device is also not particularly limited. For example, a liquid crystal panel, an organic EL panel, a plasma display panel, an electronic ink type panel, etc. are mentioned. Depending on the type of the display panel, the display device may further include a backlight unit. In addition, conventionally known ones such as other touch panels may be further provided.

In the display device, from the viewpoint of protecting the outermost surface of the anti-reflection film, an anti-fouling film (AFP film: Anti Finger Print (anti-fingerprint) film) may be further formed on the surface of the anti-reflection film. When the antifouling film is formed, it is preferable that the low-refractive-index layer, which is the outermost layer of the antireflection film, be a layer mainly containing SiO ₂ from the viewpoint of bonding properties related to durability.

The anti-fouling film is laminated on the anti-reflection film, so when the anti-reflection film is formed on both main surfaces of the cover glass, the anti-fouling film can also be formed on both surfaces of the anti-reflection film. On the other hand, the antifouling film only needs to be installed at a place that is likely to be touched by human hands or the like. Therefore, it is sufficient to form an antifouling film at least on the surface of the antireflection film on the outermost layer side of the display device.

The antifouling film may be composed of, for example, a fluorine-containing organosilicon compound. The fluorine-containing organosilicon compound can be used without any particular limitation as long as it can impart antifouling properties, water repellency, and oil repellency. For example, a fluorine-containing organosilicon compound having one or more groups selected from the group consisting of a polyfluoropolyether group, a polyfluoroalkylene group, and a polyfluoroalkyl group can be mentioned. Furthermore, the polyfluoropolyether group is a divalent group having a structure in which a polyfluoroalkylene group and an etheric oxygen atom are alternately bonded.

In addition, a commercially available fluorine-containing organosilicon compound having one or more groups selected from the group consisting of a polyfluoropolyether group, a polyfluoroalkylene group, and a polyfluoroalkyl group can also be used. Specifically, KP-801 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY178 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY-130 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY-185 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) can be preferably used. Trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) OPTOOL (registered trademark) DSX and OPTOOL AES (both trade names, manufactured by Daikin Corporation), etc.

The display device of the present embodiment is suitable for in-vehicle information equipment such as navigation systems and audio equipment, portable communication equipment, signage, and the like. [Example]

Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these Examples. In addition, Example 1 - Example 3 are an Example, and Example 4 is a comparative example.

(Example 1) A chemically strengthened glass plate of 50 mm×50 mm×2 mm (Dragontrail (registered trademark) manufactured by AGC) was used as the cover glass. TiO ₂ is used as a high refractive index material, and SiO ₂ is used as a low refractive index material, which are sequentially laminated on one main surface of the cover glass by a magnetron sputtering method. In this way, a cover glass with an antireflection film formed by alternately laminating TiO ₂ layers, which are high-refractive index layers, and SiO ₂ layers, which are low-refractive index layers, is obtained. The anti-reflection film is an 8-layer laminated film whose outermost layer is a low refractive index layer. The thickness of each layer is 97 nm (low refractive index layer), 28 nm (high refractive index layer), 16 nm (low refractive index layer) Refractive index layer), 81 nm (high refractive index layer), 10 nm (low refractive index layer), 41 nm (high refractive index layer), 36 nm (low refractive index layer), 6 nm (high refractive index layer).

(Example 2) A cover glass with an antireflection film was obtained in the same manner as in Example 1, except that the number of layers of the high refractive index layer and the low refractive index layer in the antireflection film and the thickness of each layer were changed to the following. The outermost layer of the antireflection film is a 12-layer laminate film with a low refractive index layer. The thickness of each layer is 93.3 nm (low refractive index layer), 26 nm (high refractive index layer), 10 nm (low refractive index layer) from the outermost layer side. Refractive index layer), 75.3 nm (high refractive index layer), 8 nm (low refractive index layer), 32.3 nm (high refractive index layer), 25.9 nm (low refractive index layer), 17.5 nm (high refractive index layer).

(Example 3) On the surface of a transparent hard coat (CHC) film (manufactured by TOPPAN TOMOEGAWA OPTICAL FILMS), a layer containing silicon nitride (SiN) was deposited to a thickness of 15 nm. Next, using TiO ₂ as a high-refractive index material and using SiO ₂ as a low-refractive index material, these are sequentially laminated on a layer containing silicon nitride (SiN) by a magnetron sputtering method. In this way, a CHC film with an antireflection film formed by alternately laminating TiO ₂ layers, which are high-refractive index layers, and SiO ₂ layers, which are low-refractive index layers, is obtained. The CHC film with the anti-reflection film was attached to the chemically strengthened glass plate of 50 mm × 50 mm × 2 mm through an adhesive layer with a thickness of 25 μm (TD06A manufactured by Kashiwa Paper Co., Ltd.) so that the CHC film was on the side of the chemically strengthened glass plate. Tempered glass plate (Dragontrail (registered trademark) manufactured by AGC Corporation). The anti-reflection film is an 8-layer laminated film with a low refractive index layer as the outermost layer. The thickness of each layer from the outermost layer is 98 nm (low refractive index layer), 29 nm (high refractive index layer), 16 nm (low refractive index layer) Refractive index layer), 87 nm (high refractive index layer), 11 nm (low refractive index layer), 44 nm (high refractive index layer), 34 nm (low refractive index layer), 10 nm (high refractive index layer). Furthermore, an antifouling film (KY-185, manufactured by Shin-Etsu Chemical Co., Ltd.) of 4 nm was deposited on the surface of the antireflection film.

(Example 4) A cover glass with an antireflection film was obtained in the same manner as in Example 1, except that the number of layers of the high-refractive index layer and the low-refractive index layer in the antireflection film and the thickness of each layer were changed to the following. The anti-reflection film is a 5-layer laminated film whose outermost layer is a low refractive index layer. The thickness of each layer is 80 nm (low refractive index layer), 122 nm (high refractive index layer), 36 nm (low refractive index layer) Refractive index layer), 6 nm (high refractive index layer), 16 nm (low refractive index layer).

(Evaluate) The visible light reflectance and infrared light reflectance of the antireflection film, and the visible light transmittance and infrared light transmittance of the cover glass with the antireflection film were determined using a spectrophotometer (Solid Spec-3700 manufactured by Shimadzu Corporation). The visible light reflectance and the infrared light reflectance were measured at 550 nm and 950 nm, respectively. In addition, the visible light transmittance and the infrared light transmittance were measured at 550 nm and 950 nm, respectively, and the vertical transmittance was obtained. The results are shown in Table 1.

The color index a ^* value and the color index b ^* value were determined based on JIS Z 8729:2004 from the reflection spectrum measured using the above-mentioned spectrophotometer. The results are shown in Table 1.

[Table 1] Table 1 example 1 Example 2 Example 3 Example 4 Thickness of low refractive index layer (nm) 3rd layer from the outermost layer 16 10 16 36 5th layer from the outermost layer 10 8 11 16 Visible light reflectance (%) 0.30 0.19 0.40 5.6 Infrared light reflectivity (%) 0.86 0.26 0.93 2.3 Visible light transmittance (%) 95.31 95.39 93.91 93.80 Infrared transmittance (%) 94.68 95.18 93.63 97.70 a*value(%) -0.59 2.21 -0.01 5.81 b*value (%) -6.54 -4.85 -5.38 -23.83

According to the above results, the antireflection film provided on the cover glass is made into the low-refractive index layer as the outermost layer, and the thickness of the third and fifth low-refractive index layers from the outermost layer is reduced, respectively. , which can greatly reduce the reflectivity of infrared light.

The present invention has been described in detail with reference to the specific embodiments, but it should be understood by those skilled in the art that various changes and corrections can be added without departing from the spirit and scope of the present invention. This application is based on Japanese Patent Application (Japanese Patent Application No. 2020-211763) filed on December 21, 2020, the contents of which are incorporated herein by reference. [Industrial Availability]

When the cover glass with anti-reflection film of the present invention is used in a display device equipped with an infrared sensor, it is not necessary to form a part of the cover glass with an opening to achieve good visibility and high infrared light transmittance. Moreover, from a design viewpoint, it can suppress that designability is impaired, and it can suppress that the cost increase by a drilling process is also suppressed. Therefore, it is possible to achieve high designability and suppress malfunction of the infrared sensor at the same time, which is useful for display devices, more specifically, for in-vehicle information equipment such as navigation systems and audio, portable communication equipment, signage, etc. useful for the purpose.

1: Anti-reflection film 2: Cover glass 3: Display part 4: Infrared sensor 5: Printing layer 6: IR through the ink printing layer 10: Display device 11: Low refractive index layer located in the outermost layer 12: Low refractive index layer located at the third layer from the outermost layer 13: Low refractive index layer located at the 5th layer from the outermost layer 14: Low refractive index layer in contact with cover glass 21: High-refractive index layer located at the second layer from the outermost layer 22: High-refractive-index layer located at the 4th layer from the outermost layer 23: High-refractive-index layer located at the sixth layer from the outermost layer

FIG. 1 is a schematic cross-sectional view of a display device as an example of the prior art. 2 is a schematic cross-sectional view when the cover glass with an antireflection film according to an embodiment of the present invention is applied to a display device. FIG. 3 is a schematic cross-sectional view showing the structure of an antireflection film according to an embodiment of the present invention.

1: Anti-reflection film

2: Cover glass

11: Low refractive index layer located in the outermost layer

12: Low refractive index layer located at the third layer from the outermost layer

13: Low refractive index layer located at the 5th layer from the outermost layer

14: Low refractive index layer in contact with cover glass

21: High-refractive-index layer located at the second layer from the outermost layer

22: High-refractive-index layer located at the 4th layer from the outermost layer

23: High-refractive-index layer located at the sixth layer from the outermost layer

Claims (7)

A cover glass with anti-reflection film, which is a cover glass with anti-reflection film, The above-mentioned antireflection film is formed by alternately laminating high-refractive-index layers and low-refractive-index layers, and the outermost layer is a low-refractive-index layer, The total number of laminated layers of the high-refractive index layer and the low-refractive index layer is 5 or more, The thickness of the low-refractive-index layer located in the third layer from the above outermost layer is 35 nm or less, and the thickness of the low-refractive index layer located in the fifth layer from the above-mentioned outermost layer is 15 nm or less. The cover glass with anti-reflection film as claimed in claim 1, wherein the above-mentioned anti-reflection film has a reflectance of visible light at a wavelength of 550 nm of 0.4% or less, and a reflectance of infrared light at a wavelength of 950 nm of less than 5%. The cover glass with antireflection film according to claim 1 or 2, wherein the refractive index of the high refractive index layer at a wavelength of 550 nm is 1.9 or more, and the refractive index of the low refractive index layer at a wavelength of 550 nm is 1.6 or less. The cover glass with antireflection film according to any one of claims 1 to 3, wherein the high refractive index material constituting the high refractive index layer comprises a material selected from the group consisting of Mo, W, Mg, Si, Nb, Ti, Zr, Ta , at least one oxide of the group consisting of Al, Sn and In. The cover glass with antireflection film according to any one of claims 1 to 4, wherein the low refractive index material constituting the low refractive index layer is selected from the group consisting of SiO ₂ , MgF ₂ , and materials including mixed oxides of Si and Sn , at least one of the group consisting of a material comprising a mixed oxide of Si and Zr, and a material comprising a mixed oxide of Si and Al. The cover glass with an antireflection film according to any one of claims 1 to 5, which is used together with an infrared sensor, does not have an opening at the portion where the incoming and outgoing light of the infrared sensor is transmitted. A display device comprising an infrared sensor and a cover glass with an anti-reflection film according to any one of claims 1 to 6.

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