JP2017097042A - Protective member for display, and portable terminal using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a protective member for displays comprising a light permeable substrate having a through-hole in the surface, and an infrared ray transmission member secured in the through-hole, the protective member for displays being such that the presence of the infrared ray transmission member is not so much conspicuous from the outside, making the protective member look good by appearance.SOLUTION: Provided is a protective member 1 for displays comprising a light permeable substrate 2 having a through-hole 3 in the surface, and an infrared ray transmission member 4 secured in the through-hole 3, with an antireflection film formed on the surface of the infrared ray transmission member 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a protective member for a display and a portable terminal using the same, and more specifically to a protective member for a display having a through hole for operating an infrared sensor and a portable terminal using the same.

  Devices such as mobile phones, digital cameras, and mobile terminals are widely used and tend to become increasingly popular. Conventionally, in these applications, a resin substrate made of acrylic or the like has been used as a protective member for protecting the display. However, since the acrylic resin substrate has a low Young's modulus, it tends to bend when the display surface of the display is pressed with a pen or a human finger, and the resin substrate may come into contact with the internal display and display defects may occur. there were. In addition, the acrylic resin substrate has a problem in that the surface is easily scratched and the visibility is easily lowered. One method for solving these problems is to use a glass plate as a protective member. This glass plate (cover glass) has (1) high mechanical strength, (2) low density and light weight, (3) low cost and a large amount of supply, and (4) excellent foam quality. (5) It is required to have a high light transmittance in the visible range, and (6) to have a high Young's modulus so that it is difficult to bend when the surface is pushed with a pen or a finger. In particular, when the requirement of (1) is not satisfied, since it is no longer used as a protective member, a glass plate (so-called tempered glass plate) that has been tempered by ion exchange treatment or the like has been conventionally used (for example, Patent Document 1).

  In recent years, an infrared sensor that detects the movement of a person and controls ON / OFF has been researched and developed. With such an infrared sensor, ON / OFF control can be performed by detecting the presence or absence of slight infrared rays emitted from the human body. As an application of this detection technology, in order to reduce the power consumption of the device, it is determined by the infrared sensor whether there is a person in front of the screen, and on / off control of the device power supply is automatically controlled based on this determination Is being considered.

  However, when this infrared sensor is used for a portable terminal as described above, detection of infrared rays having a wavelength of 5 to 20 μm becomes a problem. Specifically, when a protective member made of tempered glass is used to protect the display of the mobile terminal, this protective member does not transmit infrared light having a wavelength of 5 to 20 μm, and therefore becomes an obstacle to infrared detection.

  Thus, it is conceivable to provide an infrared transmission part on the surface of the protective member. Specifically, in the translucent substrate constituting the protective member, it is conceivable that a through hole is formed at a position corresponding to the infrared sensor, and the infrared transmitting member is disposed in the through hole (see, for example, Patent Document 2). .

JP 2006-83045 A JP, 2015-91739, A

  When the infrared transmitting member is disposed in the through hole formed in the light transmitting substrate, there is a problem that the appearance is inferior due to the difference in material between the light transmitting substrate and the infrared transmitting member.

  The present invention has been made in view of the above circumstances, and its technical problem is for a display including a light-transmitting substrate having a through-hole on a surface and an infrared transmitting member fixed in the through-hole. The present invention is to create a protective member for a display, which is a protective member, and the presence of an infrared transmitting member is not conspicuous from the outside, and has a beautiful appearance.

  The display protective member of the present invention is a display protective member comprising a translucent substrate having a through-hole on the surface and an infrared transmitting member fixed in the through-hole, on the surface of the infrared transmitting member. An antireflection film is formed.

The reason why the presence of the infrared transmitting member disposed in the through-hole of the transparent substrate in the protective member for display is conspicuous is the reflectance on the surface of both members, that is, the refractive index of both members affecting the reflectance. The difference is considered to be the cause. For example, when a tempered glass substrate containing SiO ₂ as a main component as a translucent substrate and a glass member containing TeO ₂ as a main component as an infrared transmitting member are used, the refractive index (nd) of each member is about 1 respectively. .4 to 1.6 (more specifically, about 1.45 to 1.55) and about 1.8 or more (more specifically, 1.9 or more, or more than 2), so that infrared transmission is possible. The reflectance of the member is higher than that of the translucent substrate, and the member is easily noticeable from the outside.

  As a result of intensive studies by the present inventors, it is possible to reduce the difference in reflectance between the translucent substrate portion and the infrared transmitting member portion by forming an antireflection film that reduces the reflectance in the visible region on the surface of the infrared transmitting member. And found that the above problems can be solved.

  The “translucent substrate” refers to a substrate that is disposed on the front surface of the display of the image display device and has a visible light transmissivity that allows the image to be sufficiently viewed practically. The “infrared transmitting member” refers to a member having a transmittance (thickness direction) of 10% or more at a wavelength of 5 to 20 μm.

  In the display protective member of the present invention, it is preferable that an antireflection film is formed on the surface to be the viewing side of the infrared transmitting member and / or the surface opposite to the viewing side.

  In the display protective member of the present invention, the antireflection film is preferably formed of a multilayer film in which a high refractive index layer and a low refractive index layer are alternately laminated.

  In the display protective member of the present invention, the antireflection film is preferably made of at least one of oxide and fluoride.

  In the display protective member of the present invention, the translucent substrate is preferably made of tempered glass, non-alkali glass or sapphire.

  In the display protective member of the present invention, the infrared transmitting member is preferably made of oxide glass, chalcogenide glass, halogen glass, silicon, germanium, ZnSe, ZnS, or polyethylene.

  The portable terminal of this invention is equipped with said protective member for displays, It is characterized by the above-mentioned.

  In the mobile terminal of the present invention, it is preferable that an infrared sensor is disposed so as to correspond to the position of the through hole.

  If a through-hole is formed on the surface of the light-transmitting substrate and an infrared sensor is arranged below the through-hole, a slight infrared ray emitted from the human body passes through the through-hole and can be detected by the infrared sensor. The presence / absence of a person in front of the screen is determined by an infrared sensor, and based on this determination, it is possible to automatically control the power ON / OFF of the device.

(A) is a schematic plan view of the protective member for displays which concerns on one Embodiment of this invention. (B) is typical sectional drawing of the protective member for displays shown by (a). Sample No. in the examples. 1 is a schematic diagram illustrating a configuration of a SiO ₂ —Nb ₂ O ₅ multilayer film formed in 1. FIG.

  Hereinafter, embodiments of a protective member for a display according to the present invention will be described in detail with reference to the drawings. The display protective member of the present invention is not limited to the following embodiment.

(Protective member for display according to an embodiment of the present invention)
FIG. 1A is a schematic plan view of a display protection member according to an embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view of the display protection member shown in FIG. As shown in FIGS. 1A and 1B, in the display protective member 1, a through-hole 3 is formed on the surface of the translucent substrate 2, and the infrared transmitting member 4 is bonded to the through-hole 3. The adhesive 5 is fixed (the adhesive 5 is not shown in FIG. 1A). An infrared sensor 6 is disposed below so as to correspond to the position of the through hole 3. In the present embodiment, the shielding member 7 is disposed at least around the through hole 3 on the surface that should be opposite to the viewing side of the translucent substrate 2. Specifically, in this embodiment, the shielding member 7 is formed so as to cover the periphery of the screen D. The shielding member 7 is provided to prevent a peripheral member (not shown) of the infrared sensor from being seen through from the viewing side.

  An antireflection film 8 is formed on the surface 4a to be the viewing side of the infrared transmitting member 4 and the surface 4b opposite to the viewing side, respectively. When the antireflection film 8 is not formed, the presence of the infrared transmitting member 4 is easily visible from the outside due to the difference in reflectance caused by the difference in refractive index between the translucent substrate 2 and the infrared transmitting member 4. On the other hand, in this embodiment, since the antireflection film 8 is formed on the surface of the infrared transmitting member 4, the reflectance on the surface of the infrared transmitting member 4 is reduced, and the reflectance on the surface of the translucent substrate 2 is reduced. And the presence of the infrared transmitting member 4 is less noticeable from the outside. The antireflection film 8 may be formed only on one of the surface 4 a and the surface 4 b of the infrared transmitting member 4.

  Hereinafter, each component will be described.

  The light-transmitting substrate 2 is not particularly limited as long as it is a substrate that is disposed on the front surface of the display of the image display device and has a visible light transmission property that allows a sufficiently visible image. For example, the linear transmittance in the visible light wavelength region (about 400 to 800 nm) of the translucent substrate 2 is preferably 80% or more, 85% or more, particularly 90% or more. Specific examples include substrates such as tempered glass and non-alkali glass, and sapphire.

  The plate thickness of the translucent substrate 2 is preferably 2 mm or less, 1.5 mm or less, 1.3 mm or less, 1.1 mm or less, 0.9 mm or less, 0.7 mm or less, 0.5 mm or less, 0.4 mm or less, In particular, it is 0.05 to 0.3 mm. The smaller the plate thickness, the lighter the display protection member 1 can be made. However, if the plate thickness is too small, the mechanical strength tends to decrease.

  The number of through-holes 3 is not limited to one, and a plurality of through-holes 3 may be used for the purpose of increasing the infrared transmittance. In the following, “the area of the through-hole” refers to the total area when there are a plurality of through-holes. In addition, as for the area of a through-hole, it is preferable that at least any one of the opening part area of the visual recognition side or its reverse side satisfy | fills the following range.

The area of the through hole 3 on one surface of the translucent substrate 2 is 200 mm ² or less, 150 mm ² or less, 100 mm ² or less, 50 mm ² or less, 30 mm ² or less, 20 mm ² or less, 15 mm ² or less, 10 mm ² or less, 5 mm. ² or less, 2 mm ² or less, 1 mm ² or less, more preferably 0.5 mm ² or less. The smaller the area of the through-hole 3, the more difficult it is to visually recognize the through-hole 3. Therefore, the design of a portable terminal or the like is less likely to be impaired, and dust or moisture is less likely to enter the device from the through-hole 3. Reliability of terminals and the like is improved. On the other hand, if the area of the through-hole 3 is too small, infrared rays are hardly transmitted. Therefore, the area of the through hole 3 is preferably 0.1 mm ² or more, 0.2 mm ² or more, and particularly preferably 0.3 mm ² or more.

  The area of the through hole 3 on one surface may be different from the area of the through hole 3 on the other surface. For example, the cross section in the thickness direction of the through-hole 3 may be tapered so that the larger area is the infrared sensor 6 side and the smaller area is the viewing side (outside). If it does in this way, while it becomes difficult to impair the design property of a portable terminal etc., it will become difficult for dust, a water | moisture content, etc. to enter into a device from the through-hole 3. FIG. Alternatively, the through hole 3 may have a tapered cross section in the thickness direction, and the smaller area may be the infrared sensor 6 side, and the larger area may be the viewing side. In this way, infrared rays can be efficiently transmitted into the through hole 3. The taper angle (shift angle from 90 °) is preferably 0.1 to 20 °, 0.5 to 15 °, and particularly preferably 1 to 10 °.

In the translucent substrate 2, the ratio of [area of through-hole on one surface (mm ² )] / [thickness (mm)] is 0.5 or more, 1 or more, 3 or more, 5 or more, 10 or more, particularly It is preferable that it is 15 or more. If the ratio is too small, infrared rays are difficult to pass through the through-hole 3. On the other hand, the ratio is preferably 800 or less, 600 or less, 500 or less, 300 or less, 200 or less, particularly 100 or less. If the ratio is too large, the through-hole 3 is easily visible, and the design of the mobile terminal or the like is likely to be impaired. Furthermore, since dust, moisture, etc. are likely to enter the device through the through hole 3, the reliability of the portable terminal or the like is likely to be lowered.

As the infrared transmissive member 4, glass such as oxide glass, chalcogenide glass, and halogen glass, metal such as silicon and germanium, crystal such as ZnSe and ZnS, and resin such as polyethylene can be used. Among these, oxide-based glass is preferable from the viewpoints of appearance and mechanical strength. The oxide glass preferably has, as a glass composition, one or more of TeO ₂ , Bi ₂ O ₃ , Al ₂ O ₃ , and TiO ₂ as main components, and the total amount of the above components is 20 mol% or more. In particular, it is preferably 30 mol% or more. In addition to the above components, alkali metal oxides, alkaline earth metal oxides, ZnO, rare earth oxides, and the like can be added to promote vitrification. Note that SiO ₂ , B ₂ O ₃ , and P ₂ O ₅ are components that promote vitrification but reduce infrared transmittance. Therefore, the total amount of these components is preferably less than 5 mol%, particularly preferably less than 1 mol%.

  The infrared transmitting member 4 is preferably arranged at the same height position as the surface that should be on the viewing side of the translucent substrate 2, and in order to prevent the infrared transmitting member 4 from being damaged, It is also preferable to arrange at a height position (desirably 10 μm or more below, particularly 100 μm or more below) lower than the surface to be viewed.

  Examples of the antireflection film 8 include a multilayer film in which high refractive index layers and low refractive index layers are alternately stacked. Examples of the low refractive index layer include silicon oxide. Niobium oxide, titanium oxide, lanthanum oxide, tantalum oxide, yttrium oxide, gadolinium oxide, tungsten oxide, hafnium oxide, aluminum oxide and other oxides; fluorides such as magnesium fluoride and calcium fluoride; nitriding A nitride such as silicon; As the antireflection film 8, a single layer film made of silicon oxide or the like can be used in addition to the multilayer film. The thickness of the antireflective film 8 is not particularly limited, but if it is too large, it will be easy to peel off, so it is preferably 500 nm or less, particularly 200 nm or less.

  Examples of the method for forming the antireflection film 8 include vacuum deposition, ion plating, and sputtering. The antireflection film 8 may be formed on the infrared transmitting member 4 processed into a predetermined shape (columnar shape or truncated cone shape). The antireflection film 8 is formed on the surface of the original plate for obtaining the infrared transmitting member 4. After forming, it may be processed into a predetermined shape. However, in the latter case, the antireflection film 8 is likely to be peeled off during the processing step, so the former is preferable.

  In addition, the reflectance in the visible light wavelength region (for example, 400 to 800 nm) of the infrared transmitting member 4 on which the antireflection film 8 is formed is preferably 15% or less, particularly preferably 10% or less. The linear transmittance in the infrared region (for example, 5 μm) is preferably 60% or more.

  As the adhesive 5, it is preferable to use an organic resin such as a two-component mixed system or a UV curable system, or an inorganic material such as a low-melting glass or a ceramic. Specific examples of the organic resin include acrylic, silicon, urethane, polyamide, vinyl acetate, ester, styrene, silicon, cyanoacrylate, PVA, PP, PC, PET, PMMA type, PES type, PEN type, and cellulose type are mentioned. You may use these in mixture of 2 or more types. If an organic resin is used, the bonding operation is facilitated. When an inorganic material is used, airtightness is improved, so that moisture or the like hardly enters the device from the through hole.

  The adhesive 5 may be colored by containing a pigment or the like. For example, when the color of the adhesive 5 is substantially the same as that of the shielding member 7, the adhesive 5 becomes less conspicuous from the outside, which is preferable in appearance. Specifically, when the shielding member 7 is black, the adhesive 5 is also preferably black, and when the shielding member 7 is white, the adhesive 5 is also preferably white. Known pigments can be used, and examples thereof include organic black pigments such as carbon black, aniline black, and perylene black, and pigments such as inorganic black and titanium black containing Cu, Fe, Cr, Mn, Co, and the like. .

  The material of the shielding member 7 is not particularly limited, and examples thereof include resin, metal, ceramics, and the like. The shielding member 7 can shield at least peripheral members of the infrared sensor. The shielding member 7 may be an independent member (for example, a shielding plate), but may be a film (shielding film) formed on the surface of the translucent substrate 2. In this case, the shielding film can be formed by a known printing method (for example, a screen printing method) using, for example, the materials listed as specific examples of the adhesive 5.

(Mobile terminal according to an embodiment of the present invention)
The portable terminal of this invention is equipped with said protective member for displays, It is characterized by the above-mentioned. Some of the technical features of the portable terminal of the present invention have already been described in the description column of the display protective member of the present invention, and the description thereof is omitted here.

  In the portable terminal of the present invention, it is preferable that an infrared sensor is disposed so as to correspond to the position of the through hole formed in the surface of the light-transmitting substrate. In this way, a small amount of infrared rays emitted from the human body can pass through the through hole and be detected by the infrared sensor.

  Hereinafter, the present invention will be described based on examples. The present invention is not limited to the following examples. The following examples are merely illustrative.

  Table 1 shows an example (No. 1-2) and a comparative example (No. 3) of the present invention, respectively.

(1) Production of translucent substrate In mass%, SiO ₂ 61.6%, Al ₂ O ₃ 18%, B ₂ O ₃ 0.5%, Na ₂ O 14.5%, K ₂ O 2%, Raw materials were prepared by preparing raw materials so as to have a glass composition of MgO 3% and SnO ₂ 0.4%. The raw material batch was melted at 1580 ° C. for 8 hours and clarified, then molded by the overflow down draw method and further cut to obtain a 0.7 mm thick glass plate. About this glass plate, after forming a φ5mm through hole on the surface using a predetermined drill, the inner peripheral surface of the through hole is polished, and the cut surface of the glass plate is subjected to corner cutting (surface direction) and chamfering. Processing (thickness direction) was performed. This glass plate was immersed in a KNO ₃ bath maintained at 430 ° C. for 4 hours and subjected to ion exchange treatment to obtain a light-transmitting substrate (refractive index nd = 1.5).

(2) Production of Infrared Transmitting Member A raw material batch was prepared by preparing raw materials so as to have a glass composition of TeO ₂ 80% and ZnO 20% in mol%. The raw material batch was melted with stirring at 800 to 1000 ° C. for 30 minutes to 2 hours, and the molten glass was cast on a carbon plate to form a plate shape. The obtained plate glass was processed into a disk shape having a diameter of 4.9 mm and a thickness of 0.5 mm, and both surfaces were mirror-finished. Antireflection films described in Table 1 were formed on both surfaces by sputtering. Sample No. The structure of the SiO ₂ —Nb ₂ O ₅ multilayer film formed in FIG.

  The light reflectance in the visible region (wavelength 400 to 800 nm) was measured for an infrared transmitting member having an antireflection film (No. 3 was not formed with an antireflection film). Further, the transmittance in the infrared region (wavelength 5 μm) was measured. The results are shown in Table 1.

(3) Production of protective member for display A shielding film was formed on the surface of the translucent substrate to be on the infrared sensor side by performing a printing process using a UV curable resin containing a black pigment. A UV curable system containing a black pigment similar to the above as an adhesive in the gap between the infrared transmitting member and the light transmitting substrate in the through hole after the infrared transmitting member is disposed at the center position of the through hole of the light transmitting substrate. The infrared transmissive member was adhered and fixed in the through hole by injecting resin and curing the UV curable resin with UV light (wavelength 360 nm, irradiation for 3 minutes). In this way, a protective member for display was obtained.

  Visually confirm the appearance of the obtained protective member for display. “◎” indicates that the infrared transmitting member is hardly visible, “○” indicates that the infrared transmitting member is slightly visible, and clearly indicates the infrared transmitting member. What was possible was evaluated as "x". The results are shown in Table 1.

(4) Discussion of results As shown in Table 1, No. 1 as an example. In 1 and 2, the visible light reflectance of the infrared transmitting member was 15% or less, and the appearance was excellent. In particular, no. The sample No. 1 had a visible light reflectance of 8.4%, which almost coincided with the reflectance of the translucent substrate, and therefore the infrared transmitting member was hardly visible.

  On the other hand, a comparative example No. In No. 3, the visible light reflectance of the infrared transmitting member was as high as 20%, the infrared transmitting member was clearly visible, and the appearance was poor.

DESCRIPTION OF SYMBOLS 1 Display protective member 2 Translucent substrate 3 Through-hole 4 Infrared transmitting member 5 Adhesive 6 Infrared sensor 7 Shielding member 8 Antireflection film

Claims (8)

  A protective member for a display comprising a translucent substrate having a through hole on the surface and an infrared transmitting member fixed in the through hole, wherein an antireflection film is formed on the surface of the infrared transmitting member A protective member for a display.   2. The display protection member according to claim 1, wherein the antireflection film is formed on a surface to be the viewing side of the infrared transmitting member and / or a surface opposite to the viewing side.   3. The display protective member according to claim 1, wherein the antireflection film is formed of a multilayer film in which a high refractive index layer and a low refractive index layer are alternately laminated.   The said reflection preventing film consists of at least 1 sort (s) of an oxide and fluoride, The protective member for a display as described in any one of Claims 1-3 characterized by the above-mentioned.   The said translucent board | substrate consists of tempered glass, an alkali free glass, or sapphire, The protective member for displays as described in any one of Claims 1-4 characterized by the above-mentioned.   The display device according to claim 1, wherein the infrared transmitting member is made of oxide glass, chalcogenide glass, halogen glass, silicon, germanium, ZnSe, ZnS, or polyethylene. Protective member.   A portable terminal comprising the display protective member according to claim 1. The mobile terminal according to claim 7, wherein an infrared sensor is disposed so as to correspond to the position of the through hole.