Viewing angle control body and method for manufacturing same

Abstract

Provided are a viewing angle control body and a method for manufacturing the same, which are capable of eliminating the risk of warping or deformation even if the viewing angle control body is thicker in order to reduce the viewing range or, for example, the setting environment of an image display device is at a high temperature, and a method for manufacturing the viewing angle control body. A sheet-shaped viewing angle control body (1) is provided with: a shutter layer (2) in which a plurality of light-transmitting tapes (3) and light-shielding tapes (4) are alternately arranged side by side; a pair of adhesive layers (5) that are respectively laminated on both surfaces of the shutter layer (2); and a pair of light-transmitting polycarbonate resin films (6) that are respectively laminated and adhered to the pair of adhesive layers (5). In order to control the viewing angle of an entertainment monitor mounted on the passenger seat side of the dashboard of an automobile, light-transmitting tapes (3) of a shutter layer (2) are formed from light-transmitting silicone rubber, light-shielding tapes (4) of the shutter layer (2) are formed from colored silicone rubber, and the light-shielding tape width of the light-shielding tapes (4) is 10-20 [mu] m (inclusive). The shutter layer 2 is made of silicone rubber, so that the risk of warpage or deformation caused by heat can be eliminated.

Description

Technical Field

[0001] The present invention relates to a viewing angle control body and a manufacturing method thereof which can restrict a driver from peeking at an image display device on a passenger seat side while driving a car. Background Art

[0002] In recent years, four-wheeled vehicles are equipped with various devices, and one of them is an entertainment monitor. The entertainment monitor is arranged on the passenger seat side of the dashboard of the vehicle or on the upper back of the driver's seat and / or the passenger seat to display various images and play music to make driving comfortable. However, when the entertainment monitor is installed on the passenger seat side of the dashboard of the car, although comfortable driving can be expected, there is a risk that the driver in the driver's seat may peek at the image on the entertainment monitor on the passenger seat side while driving the car, resulting in careless driving with reduced concentration and attention, which may lead to unexpected situations.

[0003] As a means to eliminate such concerns, the following method can be listed: a viewing angle control body that controls the viewing angle (visible range) is installed on the entertainment monitor on the passenger seat side. Through the viewing angle control body, the viewing angle is narrowed to make it difficult for the driver to visually identify the entertainment monitor on the passenger seat side, thereby limiting peeking. Conventional viewing angle controllers are not shown in the figure, but are formed as light control films having louver layers in which a plurality of transmissive regions and absorptive regions are alternately arranged (see Patent Documents 1 and 2). When the viewing angle is narrowed, the louver layers are formed thicker. Prior Art Literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application No. 2021-507285; Patent document 2: International Publication No. WO2018 / 225714. Summary of the invention Problems to be solved by the invention

[0005] Conventional viewing angle control bodies are formed as described above, and the louver layer is formed by arranging a plurality of transmission areas and absorption areas. When the viewing angle is reduced, the louver layer is relatively thick, and thus there is a risk of warping. In particular, in the case of the light control film of Patent Document 1, the heights of the plurality of transmission areas and absorption areas are different, and the front and back (up and down) are asymmetrical, and thus there is a problem of easy warping. In the case where the viewing angle control body is not seamlessly affixed to the image display portion of the entertainment monitor for integration, but another viewing angle control body is embedded in the retaining frame of the entertainment monitor in order to reduce manufacturing costs, the control of the viewing angle becomes difficult due to the warping of the viewing angle control body, and thus the problem becomes serious.

[0006] In addition, when the entertainment monitor with the viewing angle control body installed is installed on the dashboard of the car, the dashboard is in a position where it is easily exposed to sunlight, and sometimes the temperature becomes as high as about 80°C even inside the car, so sometimes the viewing angle control body is greatly warped due to the high temperature. If the viewing angle control body is greatly warped, the components of the entertainment monitor are compressed, resulting in problems such as Newton rings, which reduces visual recognition.

[0007] The present invention is made in view of the above, and its purpose is to provide a viewing angle control body and a manufacturing method thereof, which can eliminate the risk of warping or deformation even if it is thicker to narrow the visible range or the installation environment of the image display device becomes high temperature. Solutions to Solve Problems

[0008] In order to solve the above-mentioned problem, the present invention provides an image display device embedded in the passenger seat side of the dashboard of a car, and a viewing angle control body that restricts the driver from peeking at the image display device on the passenger seat side by controlling the viewing angle within a predetermined range, characterized in that: The invention comprises a louver layer in which a plurality of light-transmitting bands and light-shielding bands are alternately arranged side by side, a plurality of adhesive layers respectively laminated on both sides of the louver layer, and a plurality of light-transmitting polycarbonate resin films respectively laminated and bonded to the plurality of adhesive layers. The light-transmitting bands of the louver layer are formed by light-transmitting silicone rubber, and the light-shielding bands of the louver layer are formed by colored silicone rubber, so that the light-shielding bands of the louver layer have a width of 10 μm or more.

[0009] Furthermore, the aspect ratio of the light-transmitting band, which is obtained by dividing the thickness of the louver layer by the width of the light-transmitting band, can be set to 5 or more and 13 or less. In addition, the aspect ratio of the light-shielding band obtained by dividing the thickness of the louver layer by the light-shielding band width can be set to 16 or more and 97 or less. In addition, the light-transmitting bands and the light-shielding bands of the louver layer can be formed to have substantially the same height so that the front and back sides of the louver layer are symmetrical.

[0010] In addition, the silicone rubber is good in that the hardness when measured by a type A durometer in accordance with JIS K 6253 is 73 to 83, the tensile strength when measured in accordance with JIS K 6251 is 7.5 MPa to 13.5 MPa, the elongation at break when measured in accordance with JIS K 6251 is 270% to 490%, and the tear strength when measured in accordance with JIS K 6252 is 8 kN / m to 28 kN / m.

[0011] In addition, in order to solve the above-mentioned problems, the present invention provides a method for manufacturing a viewing angle control body as described in claim 1 or 2, characterized in that: A plurality of silicone rubber sheets for light-transmitting tapes and silicone rubber sheets for light-shielding tapes are alternately stacked to form a laminate, which is then pressurized and cut to form a louver layer, and light-transmitting silicone rubber serving as an adhesive layer is stacked on both sides of the louver layer, and light-transmitting polycarbonate resin films are stacked and bonded to the silicone rubber serving as the adhesive layer.

[0012] Here, the image display device in the claims includes at least an entertainment monitor, a visor monitor, a flip down monitor, a DVD player, etc. In addition, the shading band width of the louver layer also includes a value of 10μm or 20μm by rounding off. The aspect ratio of the light-transmitting band also includes a value of 5 or 13 by rounding off. In addition, the physical properties of silicone rubber also include approximate values ​​as long as there is no difference in the effect. Furthermore, it is ideal that the viewing angle control body surface involved in the present invention is dorsally symmetrical, and it is good that the total light transmittance is greater than 60% and less than 80% in the measurement angle range of 20° to -20°, and preferably greater than 60% and less than 77%.

[0013] According to the present invention, the louver layer is formed of silicone rubber with excellent heat resistance, so the risk of warping or deformation caused by heat can be suppressed. In addition, in addition to silicone rubber, the polycarbonate resin film exhibits excellent heat resistance of more than 90°C, so that large warping due to high temperature can be prevented from occurring in the viewing angle control body. In addition, the shading band width of the shading band is not less than 9μm, but the thickness is more than 10μm, so a sufficient shading effect based on the shading band can be expected. Effects of the Invention

[0014] According to the present invention, there is an effect that even if the thickness is increased to reduce the visible range, or the image display device is installed in a high temperature environment, the risk of warping or deformation can be eliminated. Therefore, it is possible to effectively prevent the driver from driving carelessly by peeking at the image of the image display device on the passenger seat side while driving the car. In addition, the light shielding band width of the louver layer is 10 μm or more, so there is an effect that the risk of light leakage can be effectively eliminated.

[0015] According to the invention described in claim 2, the aspect ratio of the light-transmitting band is set to be between 5 and 13, thereby preventing the driver from peeking as the visible range is expanded. In addition, the visible range can be prevented from becoming too narrow and the image display device on the passenger seat side from being visually recognized. According to the invention described in claim 3, by limiting the numerical values ​​of the hardness, tensile strength, elongation at break, and tear strength of the silicone rubber measured by a type A durometer, it is possible to prevent the viewing angle control body from warping or deforming.

[0016] According to the invention described in claim 4, a plurality of silicone rubber sheets for light-transmitting bands and silicone rubber sheets for light-shielding bands are alternately stacked to form a stacked body, and the stacked body is pressurized and then cut to form a louver layer, thereby being able to quickly and easily manufacture a louver layer having a plurality of light-transmitting bands and light-shielding bands alternately arranged side by side. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a top view schematically showing an embodiment of the viewing angle control body involved in the present invention. Figure 2 It is a front view diagram schematically showing an embodiment of the viewing angle control body involved in the present invention. Figure 3 Yes Figure 2 The cross-sectional illustration diagram is an enlarged view of part III. Figure 4 It is an explanatory diagram schematically showing a stacked body in an embodiment of a method for producing a viewing angle control body according to the present invention. Figure 5 It is shown in Figure 4 An explanatory diagram of the state in which a stacked body is pressurized and then cut to form a louver layer. Figure 6 The silicone rubber to be the adhesive layer is shown to be laminated on Figure 5 An illustration of the state of both sides of the louver layer. Figure 7 The polycarbonate resin films are laminated and bonded to form Figure 6 An explanatory diagram of the state of the silicone rubber of the adhesive layer. Figure 8 : is a graph showing the optical characteristics in an embodiment of the viewing angle control body involved in the present invention. DETAILED DESCRIPTION

[0018] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Figures 1 to 7 As shown, the viewing angle control body 1 in this embodiment is a sheet that is preferably symmetrical on the front and back and controls the viewing angle θ1 and has the following: a louver layer 2, which is arranged with a plurality of light-transmitting bands 3 and light-shielding bands 4; a pair of light-transmitting adhesive layers 5, which are respectively laminated on both sides of the louver layer 2; and a pair of light-transmitting polycarbonate resin films 6, which are respectively laminated and bonded to the pair of adhesive layers 5. The viewing angle control body 1 is installed on an entertainment monitor on the passenger seat side of the dashboard of a car, and contributes to the achievement of Goal 9 of SDGs (the United Nations' international goals for sustainable development, sustainable development goals consisting of 17 global goals and 169 specific goals (achievement benchmarks)) adopted by the United Nations Summit.

[0019] The viewing angle control body 1 is not particularly limited, and is formed, for example, in a plane rectangular shape with a size corresponding to the size of the entertainment monitor on the front passenger seat (12.3 inches wide or 11 inches wide, etc.) and is symmetrical on the front and back. From the perspective of reliably preventing the driver of the car from visually recognizing the entertainment monitor on the front passenger seat, it functions in a manner that controls the viewing angle θ1 within a range of 15° to 30°, preferably 20° to 30°, and more preferably 20°, 25°, or 30°. Figure 1 As shown, the viewing angle control body 1 is formed in a planar rectangle (specifically, a planar oblong), but a cutout may be formed in at least a portion of the peripheral portion, at least a portion of the peripheral portion may be formed in a curve, or at least one of the four corners may be chamfered.

[0020] The angle control body 1 transmits the light of the entertainment monitor on the passenger seat side, and it is good that the overall light transmittance (total light transmittance) is 55% to 100%, preferably 60% to 80%, more preferably 60% to 77%, and more preferably 64% to 71.5%. This is because when the overall light transmittance is less than 55%, the visual recognition of the entertainment monitor from the passenger seat deteriorates. If tolerance is taken into account, the overall light transmittance is preferably 60% to 68%, and ideally about 64%, when the viewing angle θ1 of the angle control body 1 is 20°, and is preferably 66.5% to 76.5%, and ideally about 71.5%, when the viewing angle θ1 of the angle control body 1 is 30°.

[0021] The light transmittance mentioned here is the following value: in a device that uses D65 specified in JIS Z 8720 as a light source and uses a light receiving sensor to measure the intensity of the inspection light emitted from the light source, when the output value of the light receiving sensor in a state where there is no object to be measured on the optical path of the inspection light is A, and the output value in a state where the object to be measured is placed on the optical path of the inspection light and the light that has passed through the object to be measured is received by the light receiving sensor is B, the light transmittance is calculated as follows: light transmittance = (B / A) × 100 (unit: %).

[0022] Furthermore, the wavelength of the light of the entertainment monitor may be the entire range of visible light of 380 nm to 830 nm, or a part thereof.

[0023] like Figure 3 As shown, the louver layer 2 is formed by repeatedly arranging a plurality of light-transmitting bands 3 and light-shielding bands 4 alternately in a row, and the spacing from each light-transmitting band 3 to the adjacent light-shielding band 4 is set to be between 52 μm and 141 μm, and the thickness is between 0.24 mm and 1.45 mm, preferably about 0.51 mm, about 0.62 mm or about 1.20 mm.

[0024] The setting angles of the light-transmitting band 3 and the light-shielding band 4 are adjusted to be not less than 0° and not more than 1°, respectively. In addition, if the tolerance is taken into account, the spacing from each light-transmitting band 3 to the adjacent light-shielding band 4 is not less than 52μm and not more than 141μm. In order to obtain a high light-shielding ratio, it is preferably not less than 60μm and not more than 132μm, more preferably about 60μm, about 75μm, about 110μm, about 130μm, and further preferably 110μm is the most appropriate. When the viewing angle θ1 is as small as 20°, the thickness of the louver layer 2 increases due to the influence of the diffraction of light, and thus the louver layer 2 is greatly thickened. The thickness of the louver layer 2 is not less than 0.24mm and not more than 1.45mm because, as long as it is within this range, the viewing angle θ1 can be easily adjusted and it can be easily manufactured.

[0025] For example, in the case of a viewing angle control body 1 with a viewing angle of 20°, the thickness of the louver layer 2 is 0.57 mm to 1.45 mm, preferably about 1.2 mm. In contrast, in the case of a viewing angle control body 1 with a viewing angle of 25°, the thickness is 0.29 mm to 0.74 mm, preferably 0.39 mm to 0.74 mm, and more preferably about 0.62 mm. In addition, in the case of a viewing angle control body 1 with a viewing angle of 30°, the thickness is 0.24 mm to 0.62 mm, preferably 0.51 mm to 0.62 mm, and more preferably about 0.51 mm.

[0026] Regarding the louver layer 2, each light-transmitting band 3 is formed of a transparent silicone rubber having excellent heat resistance, cold resistance, moisture resistance, environmental resistance, flexibility, transparency, etc. above 90°C, and helps prevent warping or deformation. Each shading band 4 is formed of a transparent silicone rubber that has been colored to provide shading properties. These light-transmitting bands 3 and shading bands 4 are formed to have the same height, so that the louver layer 2 is symmetrical on the front and back.

[0027] As silicone rubber, for example, the following can be cited: silicone rubber composition generally called millable rubber, which is composed of diorganopolysiloxane whose molecular chain ends are blocked by hydroxysilyl or vinylsilyl groups and organic peroxide; so-called addition reaction type organic silicone rubber composition, which is a diorganopolysiloxane having at least two vinyl groups bonded to silicon atoms in the molecule, and an organic hydrogen polysiloxane having at least three hydrogen atoms bonded to silicon atoms (i.e., SiH bonding) in the molecule and a platinum catalyst. As a specific example of silicone rubber, KE-153U [manufactured by Shin-Etsu Chemical Co., Ltd.: product name] can be cited.

[0028] The density of the silicone rubber measured at 23° C. in accordance with JIS K 6268 is preferably 1.21 g / cm 3 Above 1.25g / cm3 Below, preferably 1.24 g / cm 3 In addition, from the viewpoint of preventing warping or deformation of the viewing angle control body 1, it is good that the hardness measured by a type A rubber / plastic durometer (hardness tester) according to JIS K 6253 is 73 to 83, preferably 78 to 79. In addition, from the viewpoint of preventing warping or deformation, it is good that the tensile strength measured according to JIS K 6251 is 7.5 MPa to 13.5 MPa, preferably about 10.5 MPa.

[0029] Ideally, the silicone rubber has an elongation of 270% to 490% when cut when measured according to JIS K 6251, preferably 310% to 380%. In addition, in order to prevent warping or deformation, it is good that the tear strength (crescent shape) when measured according to JIS K6252 is 8kN / m to 28kN / m, preferably 13kN / m to 18kN / m. In these measurements, measuring equipment and testing machines of M&K Co., Ltd., ITS Japan Co., Ltd., etc. can be used.

[0030] Each light-transmitting band 3 is formed of a transparent silicone rubber with a longitudinally long rectangular cross section, and transmits light from the entertainment monitor on the front passenger seat. From the perspective of both anti-peeping performance and visual recognition, the light-transmitting band width of the light-transmitting band 3 is designed to be 37 μm to 126 μm, preferably 45 μm to 115 μm, and more preferably about 45 μm, about 60 μm, about 95 μm, or about 115 μm.

[0031] It is good that the aspect ratio of the light-transmitting band 3, which is the thickness of the louver layer 2 divided by the width of the light-transmitting band involved, is greater than 5 and less than 13, preferably greater than 5.2 and less than 12.8, and more preferably greater than 5.3 and less than 12.7. This is because when the aspect ratio is less than 5, the visible range is expanded and the driver can peek. In contrast, when the aspect ratio exceeds 13, the visible range becomes too narrow, resulting in that, in the passenger seat, as long as the visual recognition position is slightly shifted to the left or right, it becomes outside the field of vision and the entertainment monitor on the passenger seat cannot be visually recognized. In addition, it is good that the transmittance when the light is incident only on the light-transmitting band 3 is greater than 75%, preferably greater than 75% and less than 100%, and more preferably greater than 85% and less than 100%.

[0032] Each shading band 4 is made of silicone rubber that has been colored to block light, and is formed in a longitudinal cross-sectional rectangle that is thinner than the light-transmitting band 3, so as to block light from the entertainment monitor on the passenger seat. Silicone rubber has a light-blocking color by adding colorants such as pigments and dyes to the type used for light-transmitting bands with the above-mentioned physical properties. Specific examples of colorants include general organic pigments or inorganic pigments such as carbon black, iron oxide, titanium oxide, yellow iron oxide, disazo yellow, and phthalocyanine blue, but black carbon black with excellent shielding properties is the most suitable. In the case where a black pigment is not used as a colorant, in order to ensure light-blocking properties, it is preferably used together with a white pigment. In addition, a single colorant may be used alone, or two or more may be used together.

[0033] The shading band 4 has the same height as the adjacent light-transmitting band 3, but from the viewpoint of reliably preventing light leakage, the shading band width is set to be 10 μm or more, preferably 10 μm or more and 20 μm or less, more preferably 15 μm or more and 20 μm or less, and further preferably 15 μm, in consideration of tolerance. The aspect ratio of the shading band 4 obtained by dividing the thickness of the louver layer 2 by the most suitable shading band width of 15 μm is 16 or more and 97 or less, preferably 34 or more and 80 or less.

[0034] The aspect ratio of the light shielding band 4 is preferably in the range of 16 to 97, but in the case of a viewing angle control body 1 with a viewing angle of 20°, for example, an aspect ratio of 38 to 97 is ideal. In contrast, in the case of a viewing angle control body 1 with a viewing angle of 30°, for example, an aspect ratio of 16 to 41 is ideal.

[0035] like Figure 3 As shown, each adhesive layer 5 is formed of transparent silicone rubber with adhesiveness, and the front and back surfaces of the louver layer 2 are bonded to the polycarbonate resin film 6 to transmit the light of the entertainment monitor on the passenger seat. For transparent silicone rubber, silicone adhesives and adhesive silicone rubber sheets that are excellent in heat resistance, cold resistance, moisture resistance, environmental resistance, flexibility, transparency, etc. above 90°C and help prevent warping or deformation are suitable. Specific examples of silicone adhesives include KE-1825 [manufactured by Shin-Etsu Chemical Co., Ltd.: product name] and KE-1056 [manufactured by Shin-Etsu Chemical Co., Ltd.: product name], etc.

[0036] The thickness of the adhesive layer 5 is set to be 10 μm to 30 μm, preferably 20 μm to 30 μm, more preferably about 20 μm or about 30 μm. In addition, it is good that the light transmittance when the light is incident only on the adhesive layer 5 is 75% or more, preferably 75% to 100%, more preferably 85% to 100%.

[0037] like Figure 3As shown, each polycarbonate resin film 6 has the characteristics of heat resistance above 90°C, weather resistance, impact resistance, dimensional accuracy, excellent transparency, difficulty in warping, and difficulty in deformation, and transmits the light of the entertainment monitor on the front passenger seat. From the viewpoint of suppressing the installation space and preventing warping, the thickness of the transparent polycarbonate resin film 6 is set to be 0.1 mm or more, preferably 0.1 mm or more and 0.2 mm or less, more preferably 0.189 mm or more and 0.2 mm or less, further preferably 0.195 mm or more and 0.2 mm or less, and further preferably about 0.2 mm. It is good that the light transmittance when the light is incident only on the polycarbonate resin film 6 is 75% or more, preferably 75% or more and 100% or less, and more preferably 85% or more and 100% or less.

[0038] Such a viewing angle control body 1 is fitted as another component into the holding frame of the entertainment monitor on the passenger seat side and is located on the backlight side. By controlling the viewing angle θ1 within the range of 20° to 30°, the driver in the driver's seat is effectively restricted from peeking at the entertainment monitor on the passenger seat side. The viewing angle θ1 of the viewing angle control body 1 is not particularly limited, but can be measured by a meter in accordance with JIS K 7361. In addition, Figure 2 The maximum light transmittance angle θ2 of the viewing angle control body 1 is not particularly limited and is adjusted according to the positional relationship between the passenger seat and the entertainment monitor on the passenger seat. The maximum light transmittance angle θ2 can also be measured by a haze meter according to JIS K 7361.

[0039] In the above-mentioned structure, when manufacturing the viewing angle control body 1, first, a plurality of transparent light-transmitting silicone rubber sheets 10 and a light-shielding silicone rubber sheet 11 colored in black are prepared, and these plurality of light-transmitting silicone rubber sheets 10 and light-shielding silicone rubber sheets 11 are alternately stacked to form a stacked body 12 (see FIG. Figure 4 The light-transmitting silicone rubber sheet 10 and the light-shielding silicone rubber sheet 11 can be manufactured by extrusion molding, calendar molding, or stamping molding. In addition, the light-transmitting silicone rubber sheet 10 and the light-shielding silicone rubber sheet 11 are preferably thermocompression bonded, but can also be alternately laminated and bonded by a silicone transparent adhesive that can be expected to be reliably bonded.

[0040] Next, the laminate 12 is heated and pressurized to form a block, and the block is cut to form a sheet-shaped louver layer 2 (see Figure 5 ), the transparent silicone rubber 13 which will become the adhesive layer 5 is laminated on both the front and back surfaces of the louver layer 2 (refer to Figure 6). As for the transparent silicone rubber 13, a silicone adhesive having a high light transmittance after curing and being expected to have reliable bonding is most suitable. As the silicone adhesive, an adhesive having a light transmittance of 65% or more, preferably 65% ​​or more and 100% or less, and more preferably 80% or more and 100% or less after being applied to the louver layer 2 and cured is most suitable.

[0041] After the transparent silicone rubber 13 serving as the adhesive layer 5 is laminated on both the front and back surfaces of the louver layer 2, the polycarbonate resin film 6 is laminated and bonded to each silicone rubber 13 (see Figure 7 ) and the silicone rubber 13 is dried and cured, the front and back surfaces of the louver layer 2 are firmly bonded to a pair of polycarbonate resin films 6, and unnecessary portions of each polycarbonate resin film 6 are removed, thereby manufacturing the viewing angle control body 1. At this time, the transparent silicone rubber 13 serving as the adhesive layer 5 may be applied and laminated on the polycarbonate resin film 6, and the polycarbonate resin films 6 may be laminated and dried and cured on the front and back surfaces of the louver layer 2 via the adhesive layer 5.

[0042] According to the above, the aspect ratio of the light-transmitting band 3 is greater than 5 and less than 13, so the louver layer 2 can be made thicker and the viewing angle θ1 can be greatly reduced. Therefore, it is possible to effectively prevent the driver from driving carelessly while peeking at the image of the entertainment monitor on the passenger seat side. In addition, the louver layer 2 and the adhesive layer 5 are formed of silicone rubber with excellent heat resistance, the light-transmitting band 3 and the light-shielding band 4 of the louver layer 2 are of the same height, and the front and back of the louver layer 2 are symmetrical, so the risk of warping or deformation caused by heat can be effectively eliminated.

[0043] Furthermore, when an entertainment monitor equipped with the viewing angle control body 1 is installed on a dashboard of a car, the dashboard may become as high as about 80°C, but the silicone rubber and polycarbonate resin film 6 have excellent heat resistance of more than 90°C, thereby effectively preventing large warping of the viewing angle control body 1 due to high temperature. Therefore, problems such as Newton rings will not be generated in the viewing angle control body 1 to reduce visual recognition.

[0044] In addition, even if another viewing angle control body 1 is embedded in the holding frame of the entertainment monitor in order to reduce manufacturing costs, the control of the viewing angle θ1 will not become difficult. In addition, silicone rubber has excellent coloring properties, so it is easy to obtain a shading band 4 with excellent concealment. Furthermore, the width of the shading band is not 1μm, 5μm, 9μm, etc., but is more than 10μm, so it can be expected that the excellent shading effect based on the shading band 4 can reliably eliminate the risk of light leakage from the shading band 4.

[0045] Furthermore, in the above-mentioned embodiment, the viewing angle control body 1 is fitted into the retaining frame of the entertainment monitor on the passenger seat side so that the viewing angle control body 1 is located on the backlight side, but the viewing angle control body 1 may be installed on the entertainment monitor so that the viewing angle control body 1 is located on the surface side. In addition, a prism sheet that makes light uniform may be installed on the entertainment monitor so that the light is converged and the converged light is incident on the viewing angle control body 1. In addition, at least one of the pair of polycarbonate resin films 6 may be subjected to an anti-glare (AG) coating treatment or a hard coating treatment to prevent light from being reflected and dazzling and becoming difficult to see. Furthermore, a protective acrylic plate may be laminated on at least one of the pair of polycarbonate resin films 6. Example

[0046] Hereinafter, embodiments of the viewing angle control body and the method for manufacturing the same according to the present invention will be described together with comparative examples. [Example 1] In order to manufacture a viewing angle control body with a viewing angle of 20°, first, a plurality of transparent silicone rubber sheets for light-transmitting belts and silicone rubber sheets for light-shielding belts colored black are prepared, and these plurality of silicone rubber sheets for light-transmitting belts and silicone rubber sheets for light-shielding belts are alternately stacked and heat-pressed to form a laminate. Each silicone rubber sheet for light-transmitting belts uses KE153U [manufactured by Shin-Etsu Chemical Co., Ltd.: product name] with a thickness of 95 μm. In contrast, the silicone rubber sheet for light-shielding belts uses KE153U [manufactured by Shin-Etsu Chemical Co., Ltd.: product name] with a thickness of 15 μm, which is a mixture of 15 parts by mass of carbon black in 100 parts by mass of silicone rubber.

[0047] When forming the laminate, the hardness, tensile strength, elongation at break, and tear strength (crescent) of the silicone rubber sheet for the light-transmitting tape used in the laminate were measured by a type A hardness tester and are shown in Table 1. As a result of the measurement, the hardness of the silicone rubber sheet measured in accordance with JIS K 6253 was 78, the tensile strength of the silicone rubber sheet measured in accordance with JIS K 6251 was 10.5 MPa, the elongation at break of the silicone rubber sheet measured in accordance with JIS K 6251 was 380%, and the tear strength of the silicone rubber sheet measured in accordance with JIS K 6252 was 18 kN / m.

[0048] Next, the laminate was heated and pressurized to form a block, the block was cut to form a louver layer with a thickness of 1.2 mm in the form of a sheet, and a silicone adhesive to be a transparent adhesive layer was applied to both the front and back surfaces of the louver layer, a polycarbonate resin (PC resin) film with a thickness of 0.2 mm was laminated and bonded to each silicone adhesive and dried and cured, and unnecessary portions of each polycarbonate resin film were removed to manufacture a viewing angle control body with a viewing angle of 20°. The silicone adhesive used was KE-1825 [manufactured by Shin-Etsu Chemical Co., Ltd.: product name].

[0049] When the manufactured viewing angle control body was measured using a measuring microscope [manufactured by Mitutoyo Co., Ltd.: product name MF-UB4020B], as shown in Tables 2 and 3, the outer dimensions were 288 mm × 108 mm, the width of the light-transmitting band of the louver layer was 95 μm, the width of the light-shielding band was 15 μm, the spacing from the light-transmitting band to the adjacent light-shielding band was 110 μm, and the thickness of the adhesive layer was 30 μm. In addition, the aspect ratio of the light-transmitting band was calculated to be 12.6.

[0050] The haze meter HM-150 [Murakami Color Research Laboratory: product name] according to JIS K 7361 was modified by attaching a rotating table, and the viewing angle of the viewing angle control body was measured and confirmed to be 20°. Specifically, a rotating table was attached to the sample placement part of the haze meter HM-150, which has an opposing light source unit and a light receiving unit. The viewing angle control body of the measurement sample size of 50 mm was placed on the rotating table and rotated, and the viewing angle was measured together with the maximum light transmittance angle. At this time, after measuring the transmittance, the operation of rotating the viewing angle control body of the measurement sample by 1° was repeated. The viewing angle (visible range) is the range where the total light transmittance is greater than 1% based on the measured value of the haze meter HM-150.

[0051] After manufacturing the viewing angle control body, three viewing angle control bodies were prepared, and the warping and dimensional changes of the outer shape were measured and evaluated as ○×. The measurement was carried out under the conditions of 120°C and 240 hours using a measuring microscope [manufactured by Mitutoyo Co., Ltd.: product name MF-UB4020B]. In addition, the ○× evaluation was ○ when no warping or outer shape changes exceeding 0.5 mm were observed in the viewing angle control body, and × when warping or outer shape changes exceeding 0.5 mm were observed in the viewing angle control body and became a problem in actual use.

[0052] [Example 2] Basically, the same as in Example 1, but in order to manufacture a viewing angle control body with a viewing angle of 20°, first, a plurality of transparent light-transmitting silicone rubber sheets and a light-shielding silicone rubber sheet colored in black are prepared, and these plurality of light-transmitting silicone rubber sheets and light-shielding silicone rubber sheets are alternately stacked and heat-pressed to form a laminate. Each light-transmitting silicone rubber sheet is changed to KE153U [manufactured by Shin-Etsu Chemical Co., Ltd.: product name] with a thickness of 45 μm.

[0053] When forming the laminate, the hardness, tensile strength, elongation at break, and tear strength of the silicone rubber sheet for the light-transmitting tape used in the laminate were measured by a type A hardness tester and are shown in Table 1. As a result of the measurement, the hardness of the silicone rubber sheet measured in accordance with JIS K6253 was 78, the tensile strength of the silicone rubber sheet measured in accordance with JIS K 6251 was 10.5 MPa, the elongation at break of the silicone rubber sheet measured in accordance with JIS K 6251 was 380%, and the tear strength of the silicone rubber sheet measured in accordance with JIS K 6252 was 18 kN / m.

[0054] Next, the laminate was heated and pressurized to form a block, the block was cut to form a 0.57 mm thick louver layer in a sheet shape, and a silicone adhesive to be a transparent adhesive layer was applied to both the front and back surfaces of the louver layer, a 0.2 mm thick polycarbonate resin film was laminated and bonded to each silicone adhesive and dried and cured, and unnecessary portions of each polycarbonate resin film were removed to manufacture a viewing angle control body with a viewing angle of 20°. The silicone adhesive used was KE-1825 [manufactured by Shin-Etsu Chemical Co., Ltd.: product name].

[0055] When the manufactured viewing angle control body was measured using a measuring microscope [manufactured by Mitutoyo Co., Ltd.: product name MF-UB4020B], as shown in Tables 2 and 3, the outer dimensions were 288 mm × 108 mm, the width of the light-transmitting band of the louver layer was 45 μm, the width of the light-shielding band was 15 μm, the spacing from the light-transmitting band to the adjacent light-shielding band was 60 μm, and the thickness of the adhesive layer was 30 μm. In addition, the aspect ratio of the light-transmitting band was calculated to be 12.7.

[0056] The haze meter HM-150 [Murakami Color Research Laboratory: product name] according to JIS K 7361 was modified by attaching a rotating table, and the viewing angle of the viewing angle control body was measured and confirmed to be 20°. Specifically, a rotating table was attached to the sample placement part of the haze meter HM-150, which has an opposing light source unit and a light receiving unit. The viewing angle control body of the measurement sample size □50mm was placed on the rotating table and rotated, and the viewing angle was measured together with the maximum light transmittance angle. At this time, after measuring the transmittance, the operation of rotating the viewing angle control body of the measurement sample by 1° was repeated. The viewing angle (visible range) is the range where the total light transmittance is 1% or more based on the measured value of the haze meter HM-150.

[0057] After manufacturing the viewing angle control body, three viewing angle control bodies were prepared, and the warping and dimensional changes were measured and evaluated as ○×. The measurement was carried out under the conditions of 120°C and 240 hours using a measuring microscope [manufactured by Mitutoyo Co., Ltd.: product name MF-UB4020B]. In addition, the ○× evaluation was ○ when no warping or shape change exceeding 0.5 mm was observed in the viewing angle control body, and × when warping or shape change exceeding 0.5 mm was observed in the viewing angle control body and it became a problem in actual use.

[0058] [Example 3] Basically, the same as in Example 1, but in order to manufacture a viewing angle control body with a viewing angle of 25°, the block was cut to form a louver layer with a thickness of 0.62 mm in the form of a sheet, and a silicone adhesive to be a transparent adhesive layer was applied to both the front and back surfaces of the louver layer, and a polycarbonate resin film with a thickness of 0.2 mm was laminated and bonded to each silicone adhesive and dried and cured, and unnecessary portions of each polycarbonate resin film were removed to manufacture a viewing angle control body with a viewing angle of 25°. The aspect ratio of the light-transmitting band of the viewing angle control body was calculated to be 6.5.

[0059] When manufacturing the viewing angle control body, the hardness, tensile strength, elongation at break, and tear strength of the silicone rubber sheet for the transmission belt used in the laminate were measured by a type A hardness tester and recorded in Table 1. As a result of the measurement, the hardness of the silicone rubber sheet measured in accordance with JIS K 6253 was 79, the tensile strength of the silicone rubber sheet measured in accordance with JIS K 6251 was 10.5 MPa, the elongation at break of the silicone rubber sheet measured in accordance with JIS K 6251 was 310%, and the tensile strength of the silicone rubber sheet measured in accordance with JIS K 6252 was 13 kN / m. After manufacturing the viewing angle control body, three viewing angle control bodies were prepared in the same manner as in Example 1, and the warpage and dimensional change of the viewing angle control body were measured and evaluated as ○×.

[0060] [Example 4] Basically, the same as in Example 3, but in order to manufacture a viewing angle control body with a viewing angle of 25°, first, a plurality of transparent light-transmitting silicone rubber sheets and a light-shielding silicone rubber sheet colored in black are prepared, and these plurality of light-transmitting silicone rubber sheets and light-shielding silicone rubber sheets are alternately stacked and heat-pressed to form a laminate. Each light-transmitting silicone rubber sheet is changed to KE153U [manufactured by Shin-Etsu Chemical Co., Ltd.: product name] with a thickness of 60 μm.

[0061] When the laminate is formed, the hardness, tensile strength, elongation at break, and tear strength of the silicone rubber sheet for the light-transmitting tape used in the laminate were measured by a type A hardness tester and are shown in Table 1. As a result of the measurement, the hardness of the silicone rubber sheet measured in accordance with JIS K6253 was 79, the tensile strength of the silicone rubber sheet measured in accordance with JIS K 6251 was 10.5 MPa, the elongation at break of the silicone rubber sheet measured in accordance with JIS K 6251 was 310%, and the tear strength of the silicone rubber sheet measured in accordance with JIS K 6252 was 13 kN / m.

[0062] Next, the laminate was heated and pressurized to form a block, the block was cut to form a louver layer with a thickness of 0.39 mm in the form of a sheet, and a silicone adhesive to be a transparent adhesive layer was applied to both the front and back surfaces of the louver layer, a polycarbonate resin film with a thickness of 0.2 mm was laminated and bonded to each silicone adhesive and dried and cured, and unnecessary portions of each polycarbonate resin film were removed to manufacture a viewing angle control body with a viewing angle of 25°. The silicone adhesive used was KE-1825 [manufactured by Shin-Etsu Chemical Co., Ltd.: product name].

[0063] When the manufactured viewing angle control body was measured using a measuring microscope [manufactured by Mitutoyo Co., Ltd.: product name MF-UB4020B], as shown in Tables 2 and 3, the outer dimensions were 288 mm × 108 mm, the width of the light-transmitting band of the louver layer was 60 μm, the width of the light-shielding band was 15 μm, the spacing from the light-transmitting band to the adjacent light-shielding band was 75 μm, and the thickness of the adhesive layer was 30 μm. In addition, the aspect ratio of the light-transmitting band was calculated to be 6.5. After the viewing angle control body was manufactured, three viewing angle control bodies were prepared in the same manner as in Example 1, and the warping and dimensional changes of the viewing angle control bodies were measured and evaluated as ○×.

[0064] [Example 5] Basically, the same as Example 1, but in order to manufacture a viewing angle control body with a viewing angle of 30°, the block was cut to form a louver layer with a thickness of 0.51 mm in the form of a sheet, and a silicone adhesive to be a transparent adhesive layer was applied to both the front and back surfaces of the louver layer, and a polycarbonate resin film with a thickness of 0.2 mm was laminated and bonded to each silicone adhesive and dried and cured, and unnecessary portions of each polycarbonate resin film were removed to manufacture a viewing angle control body with a viewing angle of 30°. The aspect ratio of the light-transmitting band of the viewing angle control body was calculated to be 5.4.

[0065] When manufacturing the viewing angle control body, the hardness, tensile strength, elongation at break, and tear strength of the silicone rubber sheet for the light-transmitting tape used in the laminate were measured by a type A hardness tester and are recorded in Table 1. As a result, the hardness of the silicone rubber sheet measured in accordance with JIS K6253 was 79, the tensile strength of the silicone rubber sheet measured in accordance with JIS K 6251 was 10.5 MPa, the elongation at break of the silicone rubber sheet measured in accordance with JIS K 6251 was 310%, and the tear strength of the silicone rubber sheet measured in accordance with JIS K 6252 was 13 kN / m. After manufacturing the viewing angle control body, three viewing angle control bodies were prepared in the same manner as in Example 1, and the warpage and dimensional change of the viewing angle control bodies were measured and evaluated.

[0066] [Example 6] Basically, the same as Example 5, but in order to manufacture a viewing angle control body with a viewing angle of 30°, first, a plurality of transparent light-transmitting silicone rubber sheets and a light-shielding silicone rubber sheet colored in black are prepared, and these plurality of light-transmitting silicone rubber sheets and light-shielding silicone rubber sheets are alternately stacked and heat-pressed to form a laminate. Each light-transmitting silicone rubber sheet is changed to KE153U [manufactured by Shin-Etsu Chemical Co., Ltd.: product name] with a thickness of 115 μm.

[0067] When the laminate is formed, the hardness, tensile strength, elongation at break, and tear strength of the silicone rubber sheet for the light-transmitting tape of the laminate were measured by a type A hardness tester and are shown in Table 1. As a result of the measurement, the hardness of the silicone rubber sheet measured in accordance with JIS K 6253 was 79, the tensile strength of the silicone rubber sheet measured in accordance with JIS K 6251 was 10.5 MPa, the elongation at break of the silicone rubber sheet measured in accordance with JIS K 6251 was 310%, and the tear strength of the silicone rubber sheet measured in accordance with JIS K 6252 was 13 kN / m.

[0068] Next, the laminate was heated and pressurized to form a block, the block was cut to form a louver layer with a thickness of 0.62 mm in the form of a sheet, and a silicone adhesive to be a transparent adhesive layer was applied to both the front and back surfaces of the louver layer, a polycarbonate resin film with a thickness of 0.2 mm was laminated and bonded to each silicone adhesive and dried and cured, and unnecessary portions of each polycarbonate resin film were removed to manufacture a viewing angle control body with a viewing angle of 30°. The silicone adhesive used was KE-1825 [manufactured by Shin-Etsu Chemical Co., Ltd.: product name].

[0069] When the manufactured viewing angle control body was measured using a measuring microscope [manufactured by Mitutoyo Co., Ltd.: product name MF-UB4020B], as shown in Tables 2 and 3, the outer dimensions were 288 mm × 108 mm, the width of the light-transmitting band of the louver layer was 115 μm, the width of the light-shielding band was 15 μm, the spacing from the light-transmitting band to the adjacent light-shielding band was 130 μm, and the thickness of the adhesive layer was 30 μm. In addition, the aspect ratio of the light-transmitting band was calculated to be 5.4.

[0070] After manufacturing the viewing angle control body, three viewing angle control bodies are prepared, and the warping and dimensional changes are measured and evaluated as ○×. The measurement is carried out under the conditions of 120°C and 240 hours using a measuring microscope [manufactured by Mitutoyo Co., Ltd.: product name MF-UB4020B]. In addition, the ○× evaluation is ○ when the warping or shape change is hardly seen in the viewing angle control body, ○ when the warping or shape change is seen in the viewing angle control body but there is no problem in actual use, and × when the warping or shape change is seen in the viewing angle control body and it becomes a problem in actual use.

[0071] [Comparative Example 1] In order to obtain a viewing angle control body, a commercially available acrylic resin sheet was prepared instead of the louver layer for comparison, and the resin sheet was used as it was as the viewing angle control body. When the viewing angle control body was measured using a measuring microscope [manufactured by Mitutoyo Co., Ltd.: product name MF-UB4020B], the outer dimensions were 288 mm × 108 mm, and the thickness of the resin sheet was 0.5 mm.

[0072] A viewing angle control body was manufactured, but since the louver layer and the polycarbonate resin film were omitted from the viewing angle control body, the hardness, tensile strength, elongation at break, and tear strength of the silicone rubber sheets of the light-transmitting band and the light-shielding band were not measured by a type A hardness tester. In addition, three viewing angle control bodies were prepared, and the warping and dimensional changes of the outer shape were measured and evaluated as ○×. The measurement was carried out under the conditions of 120°C and 240 hours using a measuring microscope [manufactured by Mitutoyo Co., Ltd.: product name MF-UB4020B]. In addition, the ○× evaluation is ○ when no warping or outer shape changes exceeding 0.5 mm can be seen in the viewing angle control body, and is × when warping or outer shape changes exceeding 0.5 mm can be seen in the viewing angle control body and become a problem in actual use.

[0073] [Comparative Example 2] Basically, the same as in Example 1, but in order to manufacture a viewing angle control body with a viewing angle of 20°, the block was cut to form a louver layer with a thickness of 1.2 mm in the form of a sheet, and a silicone adhesive to be a transparent adhesive layer was applied to both the front and back surfaces of the louver layer, and a polyethylene terephthalate resin (PET resin) film with a thickness of 0.188 mm, which is easy to warp, was laminated and bonded to each silicone adhesive and dried and cured, and unnecessary portions of each polyethylene terephthalate resin film were removed to manufacture a viewing angle control body with a viewing angle of 20°. The aspect ratio of the light-transmitting band of the viewing angle control body was calculated to be 12.6.

[0074] When manufacturing the viewing angle control body, the hardness, tensile strength, elongation at break and tear strength of the silicone rubber sheet for the light-transmitting belt used in the manufacturing were measured by a type A hardness tester and recorded in Table 1. As a result, the hardness of the silicone rubber sheet measured in accordance with JIS K6253 was 78, the tensile strength of the silicone rubber sheet measured in accordance with JIS K 6251 was 10.5 MPa, the elongation at break of the silicone rubber sheet measured in accordance with JIS K 6251 was 380%, and the tear strength of the silicone rubber sheet measured in accordance with JIS K 6252 was 18 kN / m. In addition, similarly to Comparative Example 1, three viewing angle control bodies were prepared, and the warpage and dimensional change of the viewing angle control bodies were measured and evaluated as ○×.

[0075] [Table 1]

[0076] [Table 2]

[0077] [Table 3]

[0078]

evaluate

[0079] In addition, the optical properties of the viewing angle control bodies of the various embodiments were measured and Figure 8 As a result, the total light transmittance of the viewing angle control body is 60% to 70% in the measuring angle range of 10° to -10°, and is 68% to 75% in the measuring angle range of 20° to -20°. The viewing angle of the viewing angle control body is the same as that of Example 1, which is a value measured by a haze meter HM-150 and a total light transmittance in the range of 1%. Based on the above optical characteristics, if the viewing angle control body of the embodiment is embedded in the retaining frame of the entertainment monitor, it is presumed that the deterioration of the visual recognizability of the entertainment monitor from the passenger seat can be prevented.

[0080] In contrast, in the case of the viewing angle control body of Comparative Example 1, a resin sheet of only acrylic resin without a viewing angle control function is used, and thus the viewing angle cannot be narrowed. In addition, when the warping and dimensional change of the viewing angle control body are measured, although there is no warping, a large dimensional change of more than -5.6 mm is observed, which casts serious doubts on the practicality. Therefore, in the case of embedding the viewing angle control body of Comparative Example 1 in the retaining frame of an entertainment monitor, it is presumed that the control of the viewing angle becomes difficult. In addition, if a polycarbonate resin film is laminated and bonded to a resin sheet of acrylic resin, it is presumed that the warping becomes larger along with the large dimensional change of the acrylic resin sheet.

[0081] In addition, when the warping and dimensional change of the viewing angle control body of Comparative Example 2 were measured, since a polyethylene terephthalate resin film was used, warping of more than 3 mm and dimensional change of more than 1.2 mm were observed, which raised doubts about the practicality. Therefore, when the viewing angle control body of Comparative Example 2 was embedded in the holding frame of an entertainment monitor, it was estimated that the control of the viewing angle became difficult, similar to Comparative Example 1. Industrial Applicability

[0082] The viewing angle control body and the manufacturing method thereof according to the present invention are used in the field of automobile manufacturing. Description of Reference Numerals

[0083] 1 View Control Body 2 louver layers 3 light-transmitting belt 4 Shading tape 5 Adhesive layer 6Polycarbonate resin film 10Silicone rubber sheet for light-transmitting belt 11Silicone rubber sheet for shading tape 12-layer stack 13 Silicone rubber θ1 viewing angle.

Claims

1. A viewing angle control body, which is an image display device embedded in the passenger seat side of the dashboard of a car, and which restricts the driver from peeking at the image display device on the passenger seat side by controlling the viewing angle within a predetermined range, characterized in that: The invention comprises a louver layer in which a plurality of light-transmitting bands and light-shielding bands are alternately arranged side by side, a plurality of adhesive layers respectively laminated on both sides of the louver layer, and a plurality of light-transmitting polycarbonate resin films respectively laminated and bonded to the plurality of adhesive layers. The light-transmitting bands of the louver layer are formed by light-transmitting silicone rubber, and the light-shielding bands of the louver layer are formed by colored silicone rubber, so that the light-shielding bands of the louver layer have a width of 10 μm or more.

2. The viewing angle control body according to claim 1, wherein: The aspect ratio of the light-transmitting band obtained by dividing the thickness of the louver layer by the width of the light-transmitting band is set to be 5 or more and 13 or less.

3. The viewing angle control body according to claim 1 or 2, wherein: The silicone rubber has a hardness of 73 to 83 when measured by a type A durometer in accordance with JIS K 6253, a tensile strength of 7.5 MPa to 13.5 MPa when measured in accordance with JIS K 6251, an elongation at break when measured in accordance with JIS K 6251 of 270% to 490%, and a tear strength of 8 kN / m to 28 kN / m when measured in accordance with JIS K 6252.

4. A method for manufacturing a viewing angle control body, which is the method for manufacturing a viewing angle control body according to claim 1 or 2, characterized in that: A plurality of silicone rubber sheets for light-transmitting tapes and silicone rubber sheets for light-shielding tapes are alternately stacked to form a laminate, which is then pressurized and cut to form a louver layer, and light-transmitting silicone rubber serving as an adhesive layer is stacked on both sides of the louver layer, and light-transmitting polycarbonate resin films are stacked and bonded to the silicone rubber serving as the adhesive layer.

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