Optical unit

Abstract

To provide an optical unit capable of securing light transmissivity of a base material by achieving both snow melting effect and anti-fog effect.SOLUTION: An optical unit 10 includes: a housing 11; a light transmitting base material 12; an optical instrument 13 arranged in an internal space 10A defined by the housing 11 and the base material 12; an anti-fog film 15 formed in a region equivalent to a path of light emitted at least from the optical instrument 13 on an internal surface of the base material 12; and a transparent conductive film 17 provided coming into contact with the anti-fog film 15, and for generating heat by power being supplied.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an optical unit.

Background Art

[0002] Optical units are used in many fields such as vehicle and motorcycle lamps, optical sensors, street lamps, cameras, etc. However, there is a problem that snow adheres to the lens of the optical unit, or the surface temperature of the lens drops below the dew point temperature, causing moisture in the air to condense into fine water droplets and fogging occurs, reducing the light transmittance of the lens. To prevent such problems, a heater is installed inside the optical unit to ensure the light transmittance of the lens.

[0003] For example, Patent Document 1 discloses a vehicle lamp including a lamp body, a lamp cover having a light-transmitting portion and attached to an opening of the lamp body to define a lamp chamber inside, and a transparent film heater that generates heat when powered, wherein a protruding portion is formed on a surface of the lamp cover on the lamp chamber side, and the transparent film heater is attached to the protruding portion by thermal caulking.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in such a vehicle appliance where the transparent film heater is separated from the lamp cover, the snow melting effect and the anti-fogging effect are insufficient, and there is a risk that the light transmittance of the lens cannot be ensured. An object of the present invention is to provide an optical unit capable of ensuring the light transmittance of a base material by achieving both a snow melting effect and an anti-fogging effect.

Means for Solving the Problems

[0006] The optical unit of the present invention is a housing, a translucent base material, and an optical device disposed in an internal space defined by the housing and the base material, an anti-fog film formed on the inner surface of the base material in at least a region corresponding to the path of light emitted from the optical device, and a transparent conductive film provided in contact with the anti-fog film and generating heat when power is supplied.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4A

Figure 4B

Figure 5

Embodiments for Carrying Out the Invention

[0008] Hereinafter, preferred embodiments of the present invention will be described, but they may be appropriately modified and combined. Also, in the following description and the accompanying drawings, substantially the same or equivalent parts will be denoted by the same reference numerals for description.

[0009] FIG. 1 is a conceptual diagram showing the optical unit 10 of the present invention and is a cross-sectional view of the optical unit 10. In the present embodiment, the optical unit 10 is a headlight for an automobile. Note that the use of the optical unit 10 is not limited to a headlight for an automobile, and it may be used for vehicle lamps such as those for automobiles and motorcycles, optical sensors, street lamps, cameras, and the like.

[0010] As shown in FIG. 1, the optical unit 10 includes a housing 11, a translucent base material 12, a first optical device 13 disposed in an internal space 10A defined by the housing 11 and the base material 12, and a second optical device 14. Further, an anti-fog film 15 is formed on the inner surface of the base material 12, and a hard coat 16 is formed on the outer surface of the base material 12. Furthermore, a transparent conductive film 17 is provided in contact with the anti-fog film 15.

[0011] The housing 11 is a housing that covers and supports a part of the optical devices 13 and 14. Specifically, the housing 11 supports the optical devices 13 and 14 via fixing devices (not shown). The housing 11 has a lower wall 11A that covers the rear side of the optical devices 13 and 14, and a first side wall 11B that extends parallel to the light-emitting direction (the left side direction in FIG. 1) of the optical devices 13 and 14, and is open at the front.

[0012] The base material 12 is fixed to the housing so as to close the opening of the housing 11. The base material 12 has an upper wall 12A that covers the front side of the optical devices 13 and 14, and a second side wall 12B that extends parallel to the light-emitting direction (the left side direction in FIG. 1) of the optical devices 13 and 14, and is open at the rear. That is, the light emitted from the optical devices 13 and 14 passes through the base material 12 and is emitted to the outside of the internal space 10A. The opening at the rear of the base material 12 is closed by the housing 11.

[0013] As the base material 12, a polycarbonate resin (PC) is used. Note that the base material 12 may be any material having light-transmitting properties that transmit at least one of the lights emitted from the optical devices 13 and 14, and hydrophobic synthetic resins such as polymethyl methacrylate resin (PMMA) and PET (polyethylene terephthalate), and hydrophobic materials such as glass may also be used.

[0014] As the first optical device 13, an LED light source is used, and as the second optical device 14, a lidar is used as a sensor in an ADAS (Advanced Driving Assistant System). Note that as the first optical device 13 and the second optical device 14, a lighting unit such as a fluorescent lamp or an incandescent bulb, an optical sensor unit that emits visible light, infrared light, ultraviolet light, or millimeter waves, or an optical sensor unit that detects visible light, infrared light, ultraviolet light, or millimeter waves may also be used. Further, an optical sensor unit that uses a light source of an optical sensor and detects reflected light of the light emitted from the light source of the optical sensor may also be used.

[0015] Note that in the present embodiment, the optical unit 10 having two optical devices, the first optical device 13 and the second optical device 14, has been described, but the number of optical devices included in the optical unit 10 may be one or three or more.

[0016] The anti-fogging film 15 is formed on the entire inner surface of the base material 12 with a film thickness of 30 μm. On the surface of the base material, when the surface temperature becomes equal to or lower than the dew point temperature, moisture in the atmosphere condenses into fine water droplets, causing fogging. Therefore, there is a problem of reducing the light transmittance and causing visual field defects and malfunction of sensors and the like. In order to suppress such problems, the anti-fogging film 15 is formed on the inner surface of the base material 12.

[0017] Note that in the present embodiment, the anti-fogging film 15 is formed on the entire surface of the base material 12, but the anti-fogging film 15 may be formed in at least a region corresponding to the path of the light emitted from the optical devices 13 and 14.

[0018] Also, in this embodiment, the film thickness of the anti-fog film 15 is set to 30 μm. However, if the transparent conductive film 17 can be contacted and the light emitted from the optical devices 13 and 14 can be transmitted, the film thickness of the anti-fog film 15 can be arbitrarily adjusted.

[0019] The anti-fog film 15 is a cured film obtained by curing an active energy ray-curable anti-fog composition. If the anti-fog composition is a heat-curable anti-fog composition and the anti-fog composition is heat-cured in a state where the transparent conductive film is in contact with the anti-fog composition, the heat used for curing the anti-fog composition is transmitted to the transparent conductive film, causing a problem of thermally deforming the transparent conductive film. Further, when insert molding is used as a method of adhering the transparent conductive film to the substrate, the heat during insert molding is also transmitted to the transparent conductive film, causing the same problem. On the other hand, since the anti-fog composition of the present invention is an active energy ray-curable type (for example, ultraviolet ray-curable type), even when the anti-fog composition is cured in a state where the transparent conductive film is in contact with the anti-fog composition, it is possible to prevent the transparent conductive film from being thermally deformed. Therefore, the reliability of the transparent conductive film can be improved.

[0020] The anti-fog composition is a solvent-free composition containing a radical-reactive material and an initiator. Here, "solvent-free type" means that the anti-fog composition does not contain a non-reactive volatile organic solvent or substantially does not contain a non-reactive volatile organic solvent. "Substantially does not contain a non-reactive volatile organic solvent" means that when the anti-fog composition is subjected to gas chromatography analysis at 200 °C, the total value of the components detected with a structure not containing a vinyl group or an acryloyl group is less than 1% by mass.

[0021] Since the anti-fog composition is of the solvent-free type, when the anti-fog composition is cured, most of it becomes a cured film as an active ingredient. Therefore, the total amount of the anti-fog composition required when applying it to the surface of the substrate 12 can be reduced.

[0022] In this embodiment, the anti-fog composition is a solvent-free type, but an organic solvent may be used to use a diluted anti-fog composition.

[0023] The radical-reactive material is a radical-reactive material composed of a resin component such as a monomer or an oligomer and contains a hydrophilic group. When the anti-fog composition is applied to the surface of the inner surface of the base material 12, at least a part of the hydrophilic group is disposed on the surface layer of the anti-fog composition. Then, by curing the anti-fog composition by a radical reaction, an anti-fog film 15 can be formed as a cured film having a hydrophilic group on the surface of the base material 12.

[0024] Since the hydrophilic group is disposed on the surface of the anti-fog film 15, the surface of the anti-fog film 15 has a hydrophilic function. Therefore, the contact angle of the surface of the anti-fog film 15 with water can be reduced. Thus, by diffusing moisture on the surface of the anti-fog film 15, a water film is formed, and the anti-fog property of the base material 12 can be ensured.

[0025] The radical-reactive material is a radical-reactive material composed of a resin component such as a monomer or an oligomer. The content of the radical-reactive material in the anti-fog composition is preferably 70 to 95% with respect to the total amount. By incorporating the radical-reactive material into the anti-fog composition, the viscosity of the anti-fog composition can be adjusted. Therefore, the anti-fog composition can be adjusted to a viscosity suitable for spray coating without dilution with an organic solvent. The viscosity suitable for spray coating is, for example, 3 to 60 mPa·s / 25°C. Thus, in the step of curing the anti-fog composition on the surface of the base material 12, a heat drying step becomes unnecessary, and the power consumption during production can be reduced.

[0026] As the radical-reactive material, polyethylene glycol diacrylate, triethylene glycol diacrylate, pentaerythritol triacrylate, 2-hydroxy-3-acryloyloxypropyl acrylate, polytetramethylene glycol diacrylate, etc. can be used. Further, these radical-reactive materials may be used alone or in combination of two or more.

[0027] The initiator is a radical generator that generates highly active radicals upon irradiation with ultraviolet light. These radical species react with resin components such as monomers and / or oligomers through decomposition and the like. This reaction product further reacts with another resin component to cause the reaction to proceed in a chain. Then, the cross-linking reaction proceeds, the molecular weight increases, the radical-reactive material is cured, and a cured film is formed.

[0028] Examples of the initiator include ketone-based ones such as benzophenone, benzoin methyl ether, benzoin propyl ether, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone; azo-based ones such as 2,2'-azobisisobutyronitrile, azobis-2-methylbutyronitrile, azobisdivaleronitrile; organic peroxide-based ones such as t-butyl peroxyisobutyrate, t-butyl peroxy-2-ethylhexanoate, t-amyl peroxy 3,5,5-trimethylhexanoate, t-butyl peroxyisopropyl carbonate, 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane, di-t-butyl peroxide, di-t-amyl peroxide; acylphosphine-based ones such as 2,6-dimethylbenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, etc. Known compounds can be used. Among these, radical cleavage-type initiators such as 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyl diphenylphosphine oxide are preferred. Also, these initiators may be used alone or in combination of two or more.

[0029] The anti-fogging composition may contain a thiol material. The thiol material is a compound containing a polyfunctional thiol group. That is, it is a compound containing two or more functional thiol groups. By containing a thiol material in the anti-fogging composition, oxygen inhibition can be suppressed by the thiol-ene reaction.

[0030] The reaction mechanism of the thiol-ene reaction is shown below. First, ultraviolet light is irradiated and the initiator cleaves or undergoes energy transfer (initiation reaction). Then, the initiator extracts an electron from the thiol material to generate a thiyl radical. The thiyl radical attacks the double bond of the monomer of the radical-reactive material to form a thioether bridge and a radical-reactive material having a radical. This further extracts hydrogen from the thiol material to generate a thiyl radical. Then, the generated thiyl radical attacks the double bond of the monomer of another radical-reactive material (growth reaction). In this way, the reaction proceeds chainwise, and the anti-fogging composition can be cured efficiently.

Chemical formula

[0031] By containing a thiol material in the anti-fogging composition, curing can be promoted by a dark reaction even in the atmosphere (oxygen atmosphere). The reaction mechanism in an oxygen atmosphere is shown below. First, oxygen and the monomer react to generate a peroxy radical. Then, the peroxy radical extracts hydrogen from the thiol to generate a thiyl radical. And the above growth reaction is followed by the thiyl radical. Therefore, the anti-fogging composition can be cured even in an oxygen atmosphere.

Chemical formula

[0032] By containing a thiol material in the anti-fogging composition, a thioether cross-linked structure can be formed, and the flexibility of the cured film can be enhanced. Therefore, the generation of cracks in a low-temperature environment can be suppressed, and the durability can be further improved. Here, the ability to enhance the flexibility of the cured film is due to the fact that in the thioether cross-linked structure, sulfur atoms can move such as by rotation.

[0033] By containing a thiol material in the anti-fog composition, the curing shrinkage can be suppressed. Curing shrinkage occurs when the double bonds of the radically reactive material polymerize by radical polymerization and change into a high molecular weight compound connected by single bonds, resulting in a shortening of the molecular bond distance. However, by containing a thiol material, the shortening of the molecular bond distance can be suppressed by forming a thioether crosslink with the double bond of the radically reactive material. Therefore, even when the anti-fog composition is cured with the transparent conductive film embedded in the anti-fog composition, the occurrence of warping or twisting of the transparent conductive film can be suppressed.

[0034] The content of the thiol material is preferably 5% by mass or more and 20% by mass or less based on the total amount of the anti-fog composition.

[0035] In addition, the anti-fog composition may contain various additives such as antibacterial agents, antifungal agents, defoaming agents, antioxidants, antistatic agents, and polymerization inhibitors in addition to the thiol material.

[0036] The hard coat 16 is formed with a film thickness of 10 μm on the entire outer surface of the base material 12. When scratches or dirt adhere to the surface of the base material, it reduces the light transmittance, causing problems such as poor visibility and malfunction of sensors. To prevent such problems by enhancing the mechanical strength of the base material 12, the hard coat 16 is formed on the outer surface of the base material 12.

[0037] In this embodiment, the hard coat 16 is formed on the entire outer surface of the base material 12. However, the hard coat 16 is not an essential component of the light source unit 10 of the present invention. That is, the hard coat 16 may be formed on a part of the outer surface of the base material 12 or may not be formed.

[0038] Also, in this embodiment, the film thickness of the hard coat 16 is set to 10 μm. However, if the light emitted from the optical devices 13 and 14 can be transmitted, the film thickness of the hard coat 17 can be adjusted arbitrarily.

[0039] The hard coat 16 is a cured film obtained by curing an active energy curable composition. If the anti-fog composition is a thermosetting anti-fog composition and the anti-fog composition is thermally cured in a state where a transparent conductive film is in contact with the anti-fog composition, there is a problem that the heat used for curing the anti-fog composition is transmitted to the transparent conductive film, causing thermal deformation of the transparent conductive film. On the other hand, since the anti-fog composition of the present invention is an active energy curable type (for example, an ultraviolet curable type), even when the anti-fog composition is cured in a state where a transparent conductive film is in contact with the anti-fog composition, it is possible to prevent the transparent conductive film from being thermally deformed.

[0040] As the composition used for the hard coat 16, the same composition as the anti-fog composition used for the anti-fog film 15 can be used. Note that, as the composition used for the hard coat 16, a composition different from the anti-fog composition used for the anti-fog film 15 may be used.

[0041] The transparent conductive film 17 serves as a so-called heater that generates heat when power is supplied. As shown in FIG. 1, the transparent conductive film 17 is embedded in the anti-fog film 15 in a region corresponding to the path of the light emitted from the electric device 14. That is, the transparent conductive film 17 is fixed to the base material 12 by the anti-fog film 15.

[0042] Since the transparent conductive film 17 is embedded in the anti-fog film 15, the heat generated by the transparent conductive film 17 is easily transmitted to the entire anti-fog film 15, and fogging can be efficiently prevented. In addition, the heat generated by the transparent conductive film 17 is easily transmitted to the entire base material 12 through the anti-fog film 15, and the snow attached to the base material 12 can be efficiently melted. Furthermore, since the anti-fog film 15 is exposed on the inner surface of the base material 12, it is possible to achieve both the snow melting function of the transparent conductive film 17 and the anti-fog function of the anti-fog film 15.

[0043] Specifically, as shown in FIG. 2A, the transparent conductive film 17 has a light-transmissive thin film member 18, a plurality of metal wirings 19, a first contact 20, and a second contact 21. When a current is applied from the first contact 20 to the second contact 21, the metal wiring 19 generates heat.

[0044] The heat generated from the metal wiring 19 is transmitted to the base material 12 or the hard coat via the base material 12, thereby melting the snow adhering to the base material 12 or the hard coat 16. In addition, the heat generated from the metal wiring 19 is transmitted to the anti-fog film 15, thereby preventing the base material 12 from fogging.

[0045] In this embodiment, the transparent conductive film 17 is disposed in a region corresponding to the path of the light emitted from the electric device 14. However, as long as the snow adhering to the base material 12 or the hard coat 16 can be melted and the fogging of the base material 12 can be prevented, it may be disposed outside the region corresponding to the path of the light emitted from the electric device 14.

[0046] In this embodiment, the transparent conductive film 17 is embedded in the anti-fog film 15. However, the transparent conductive film 17 only needs to be in contact with the anti-fog film 15 so that the snow adhering to the base material 12 or the hard coat 16 can be melted and the fogging of the base material 12 can be prevented.

[0047] Also, a part of the transparent conductive film 17 may be embedded in the anti-fog film 15. Specifically, for example, the thin film member 18 may be embedded in the anti-fog film 15, and the first contact 20 and the second contact 21 may be disposed outside the anti-fog film 15. That is, the region of the transparent conductive film 17 excluding the first contact 20 and the second contact 21 that serve as contacts with the external wiring may be embedded in the anti-fog film 15. This makes it possible to easily connect the first contact 20 and the second contact 21 to the external wiring while obtaining the above-described effects.

[0048] The thin film member 18 is formed in a flat plate shape with a thickness of 20 μm. As the material of the thin film member 18, polycarbonate resin (PC) is used. As the material of the thin film member 18, any material having light transmissibility that transmits at least one of the lights emitted from the optical devices 13 and 14 may be used, and hydrophobic synthetic resins such as polymethyl methacrylate resin (PMMA) and PET (polyethylene terephthalate), and hydrophobic materials such as glass may also be used.

[0049] The thin film member 18 preferably has a total light transmittance of 85% or more, and more preferably 90% or more. Further, in order to suppress the steps (unevenness) formed on the surface of the thin film member 18, it is preferably formed to have a thickness of 10 to 50 μm, and more preferably 10 to 30 μm. By this, the transmittance of visible light and infrared rays of the transparent conductive film 17 can be made 80% or more.

[0050] Note that, as the material of the thin film member 18, it is preferable to use a material having the same dielectric constant as that of the base material 12. By using a material having the same dielectric constant for the thin film member 18 and the base material 12, the refractive indices of light of the thin film member 18 and the base material 12 become approximate or the same, and even when the transparent conductive film 18 and the base material 12 are in contact, the boundary between the transparent conductive film 18 and the base material 12 becomes less noticeable.

[0051] The metal wiring 19 is formed of a copper wire with a wire diameter of 6 μm. As shown in FIG. 2A, a plurality of metal wirings 19 are formed in parallel at equal intervals of 2 mm from the first contact 20 to the second contact 21 in the thin film member 18. By forming the plurality of metal wirings 19 in parallel, the transmittance of millimeter waves can be improved. In this embodiment, the metal wiring 19 is a copper wire with a wire diameter of 6 μm, but the wire diameter may be 4 to 80 μm, and the material may also be formed of nickel, tungsten wire, gold, silver, or polyethylene dioxythiophene. Also, in this embodiment, the interval between the plurality of metal wirings 19 is 2 mm, but the interval may be 0.5 to 5.0 mm. It is preferable that the plurality of metal wirings 19 are formed in parallel from the first contact 20 to the second contact 21 and at intervals of 1 to 5 mm with a wire diameter of 1.0 to 8.0 μm. By forming the metal wiring 19 in such a configuration, the transmittance of millimeter waves of the transparent conductive film can be made 80% or more.

[0052] Note that, as shown in FIG. 2B, the plurality of metal wirings 19 may be formed such that two metal wirings 19 intersect near the center of the thin film member 18. That is, the plurality of metal wirings 19 may be formed in a mesh shape.

[0053] Note that the transparent conductive film 17 may be a heat generating member of a thin film having translucency, and a transparent conductive film such as an ITO film (indium tin oxide film) may be used.

[0054] A modified example of the optical unit 10 of the present invention will be described with reference to FIG. 3. FIG. 3 is a conceptual diagram showing a modified example of the optical unit 10 of the present invention and is a cross-sectional view of the modified example of the optical unit 10.

[0055] As shown in FIG. 3, the modified example of the optical unit 10 is different from the above-described embodiment in that a recess 12C is formed in the translucent base material 12 and the transparent conductive film 17 is disposed inside the recess 12C.

[0056] The recess 12C formed in the base material 12 is formed with a size larger than that of the transparent conductive film 17, and the depth of the recess 12C is, for example, 20 μm. By disposing the transparent conductive film 17 in the recess 12C formed in the base material 12, the fixing strength of the transparent conductive film 17 can be improved.

[0057] Hereinafter, a method for manufacturing the base material 12 on which the anti-fog film 15 with the hard coat 16 formed on the outer surface and the transparent conductive filter 17 embedded in the inner surface will be described in detail with reference to the flowchart of FIG. 4A. Here, the inner surface of the base material 12 refers to the surface facing the internal space 10A side when the base material 12 is incorporated into the optical unit 10, and the outer surface of the base material 12 refers to the surface facing the inner surface of the base material 12.

[0058] First, the base material 12 was fixed to the coating jig so that the outer surface side of the base material 12 faced downward in the gravitational direction (STEP1). Next, a composition for the hard coat was applied to the entire outer surface of the base material 12 (STEP2). Next, an anti-fog composition was applied to the entire inner surface of the base material 12 so as to have a film thickness of 30 μm (STEP3). Next, the transparent conductive film 17 was embedded in the anti-fog composition (STEP4). Next, ultraviolet rays were irradiated onto the inner and outer surfaces of the base material 12 (STEP5). The composition for the hard coat and the anti-fog composition were cured, and an anti-fog film 15 was formed on the inner surface of the base material 12, and a hard coat 16 was formed on the outer surface of the base material 12 (STEP6). As described above, the base material 12 on which the anti-fog film 15 with the transparent conductive filter 17 embedded in the inner surface can be manufactured.

[0059] By manufacturing the base material 12 on which the anti-fog film 15 with the transparent conductive filter 17 embedded in the inner surface is formed using such a method, the anti-fog composition can wrap around to the internal space 10A side of the transparent conductive film 17, and the anti-fog film 15 can cover the transparent conductive film 17.

[0060] In STEP5, as a method of irradiating ultraviolet rays, two ultraviolet light sources may be used to simultaneously irradiate the inner and outer surfaces of the base material 12 with ultraviolet rays, or one ultraviolet light source may be rotated around the base material 12 to alternately irradiate the inner and outer surfaces of the base material 12 with ultraviolet rays. Further, while irradiating one of the inner or outer surfaces of the base material 12 with ultraviolet rays using one ultraviolet light source, a reflecting member that reflects the ultraviolet rays emitted from the ultraviolet light source may be used to irradiate the other of the inner or outer surfaces of the base material 12 with ultraviolet rays, thereby simultaneously irradiating the inner and outer surfaces of the base material 12 with ultraviolet rays. Further, as the ultraviolet light source, in addition to a UV-LED lamp, a high-pressure mercury lamp may be used.

[0061] Next, a modified example of a method for manufacturing the base material 12 on which an anti-fogging film having a hard coat 15 formed on the outer surface and a transparent conductive filter 17 embedded in the inner surface will be described in detail with reference to the flowchart of FIG. 4B.

[0062] First, it was fixed to a coating jig so that the outer surface side of the base material 12 faced downward in the gravitational direction (STEP1). Next, a hard coat composition was applied to the entire outer surface of the base material 12 (STEP2). Next, an anti-fogging composition was applied to the entire inner surface of the base material 12 so as to have a film thickness of 10 μm (STEP3). Next, using a mounting jig, the transparent conductive film 17 was adhered to the anti-fogging composition (STEP4). Next, an anti-fogging composition was applied to an area wider than the area where the transparent conductive film 17 was attached on the inner surface of the base material 12 so as to have a film thickness of 20 μm (STEP5). Next, the inner and outer surfaces of the base material 12 were irradiated with ultraviolet rays (STEP6). The hard coat composition and the anti-fogging composition were cured, and an anti-fogging film 15 was formed on the inner surface of the base material 12, and a hard coat 16 was formed on the outer surface of the base material 12 (STEP7). As described above, the base material 12 on which the anti-fogging film 15 in which the transparent conductive filter 17 is embedded is formed can be manufactured.

[0063] By manufacturing a substrate 12 on which an anti-fog film with a transparent conductive filter 17 embedded on the inner surface is formed using such a method, it is ensured that the anti-fog composition is applied to the inner space 10A side of the transparent conductive film 17, and the anti-fog film 15 can cover the transparent conductive film 17.

Example

[0064] Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. It should be noted that the present invention is not limited to these examples.

[0065] 〔Example 1〕 As the thin film member, a 20-μm-thick film (50 mm × 100 mm) made of polyethylene terephthalate (PET) was used. Copper nanoparticles (manufactured by Taiyo Nisso Co., Ltd.) were used as the material, and a plurality of metal wirings with a wire diameter of 6 μm were formed in a mesh pattern at intervals of 500 μm on the thin film member using an R&D inkjet device (manufactured by Seiko Epson Corporation). An FPC (Flexible printed circuits) manufactured by Nippon Mektron Ltd. was attached thereto to produce a transparent conductive film. Next, the transparent conductive film was placed on a 3-mm-thick substrate (manufactured by Covestro, 150 mm × 150 mm) made of polycarbonate resin (PC), and an anti-fog composition (product name: AUP-3500, manufactured by Toxic Co., Ltd.) was spray-coated thereon to a film thickness of 30 μm. Then, using a UV-LED lamp, the anti-fog composition was cured at 365 nm with 10,000 mJ / cm 2 to obtain the molded body of Example 1.

[0066] 〔Example 2〕 A film (50 mm × 100 mm) with a thickness of 20 μm made of polyethylene terephthalate (PET) was used as the thin film member. Copper nanoparticles (manufactured by Taiyo Nippon Sanso Corporation) were used as the material, and a plurality of metal wirings with a wire diameter of 6 μm were formed on the thin film member in parallel at 2 mm intervals using an R&D inkjet device (manufactured by Seiko Epson Corporation) (parallel wiring). An FPC (Flexible printed circuits) manufactured by Nippon Mektron Ltd. was attached thereto to produce a transparent conductive film. Next, the transparent conductive film was placed on a substrate with a thickness of 3 mm made of polycarbonate resin (PC) (manufactured by Covestro, 150 mm × 150 mm). A thiol material (Karenz MT(R) PE1 manufactured by Resonac Co., Ltd.) was added to the anti-fog composition (product name: AUP-3500 manufactured by Tokushiki Co., Ltd.) so that the content ratio was 5% with respect to the total amount of the anti-fog composition, and the mixture was spray-coated from above the transparent conductive film to a film thickness of 30 μm. Then, using a UV-LED lamp, the anti-fog composition was cured at 365 nm with 10,000 mJ / cm 2 to obtain the molded body of Example 2.

[0067] 〔Example 3〕 A film (50 mm × 100 mm) with a thickness of 20 μm made of polycarbonate resin (PC) was used as the thin film member. Copper nanoparticles (manufactured by Taiyo Nippon Sanso Corporation) were used as the material, and a plurality of metal wirings with a wire diameter of 6 μm were formed on the thin film member in parallel at 2 mm intervals using an R&D inkjet device (manufactured by Seiko Epson Corporation). An FPC (Flexible printed circuits) manufactured by Nippon Mektron Ltd. was attached thereto to produce a transparent conductive film. Next, the transparent conductive film was placed on a substrate with a thickness of 3 mm made of polycarbonate resin (PC) (manufactured by Covestro, 150 mm × 150 mm). A thiol material (Karenz MT(R) PE1 manufactured by Resonac Co., Ltd.) was added to the anti-fog composition (product name: AUP-3500 manufactured by Tokushiki Co., Ltd.) so that the content ratio was 5% with respect to the total amount of the anti-fog composition, and the mixture was spray-coated from above the transparent conductive film to a film thickness of 30 μm. Then, using a UV-LED lamp, the anti-fog composition was cured at 365 nm with 10,000 mJ / cm2 It was cured to obtain the molded article of Example 3.

[0068] [Example 4] As the thin film member, a 20-μm-thick film (50 mm × 100 mm) made of polycarbonate resin (PC) was used. Copper nanoparticles (manufactured by Taiyo Nippon Sanso Corporation) were used as the material, and a plurality of metal wirings with a wire diameter of 6 μm were formed on the thin film member in parallel at 2-mm intervals using an R&D inkjet device (manufactured by Seiko Epson Corporation). An FPC (Flexible printed circuits) manufactured by Nippon Mektron Ltd. was attached thereto to produce a transparent conductive film. Next, the transparent conductive film was placed on a 3-mm-thick base material (150 mm × 150 mm, manufactured by Mitsubishi Engineering Plastics Corporation) made of polymethyl methacrylate resin (PMMA). A material obtained by adding a thiol material (Karenz MT(R) PE1, manufactured by Resonac Corporation) to an anti-fog composition (product name: AUP-3500, manufactured by Tokushiki Corporation) so that the content ratio thereof becomes 5% with respect to the total amount of the anti-fog composition was spray-coated from above the transparent conductive film so as to have a film thickness of 30 μm. Thereafter, using a UV-LED lamp, the anti-fog composition was cured at 365 nm with 10,000 mJ / cm 2 to obtain the molded article of Example 4.

[0069] [Example 5] As the thin film member, a 20-μm thick film (50 mm × 100 mm) made of polyethylene terephthalate (PET) was used. Copper nanoparticles (manufactured by Taiyo Nisso Co., Ltd.) were used as the material, and a plurality of metal wirings with a wire diameter of 6 μm were formed on the thin film member in parallel at intervals of 2 mm using an R&D inkjet device (manufactured by Seiko Epson Corporation). An FPC (Flexible printed circuits) manufactured by Nippon Mektron Ltd. was attached thereto to produce a transparent conductive film. Next, the transparent conductive film was placed on a 3-mm thick base material (150 mm × 150 mm, manufactured by Covestro) made of polycarbonate resin (PC). A thiol material (Karenz MT(R) PE1, manufactured by Resonac Co., Ltd.) was added to the anti-fog composition (product name: AUP-3500, manufactured by Tokushiki Co., Ltd.) so that the content ratio thereof was 20% with respect to the total amount of the anti-fog composition, and the mixture was spray-coated from above the transparent conductive film to a film thickness of 30 μm. Thereafter, using a UV-LED lamp, the anti-fog composition was cured at 365 nm with 10,000 mJ / cm 2 to obtain the molded body of Example 5.

[0070] [Comparative Example 1] As the thin film member, a 20-μm thick film (50 mm × 100 mm) made of polyethylene terephthalate (PET) was used. A silver nanoink (diameter: 40 nm, length: 27 μm, viscosity: 4 mPa·s, manufactured by Showa Denko) was used as the material, and a plurality of wirings with a width of 10 μm were patterned in a mesh shape on the thin film member at intervals of 30 μm using an R&D inkjet device (manufactured by Seiko Epson Corporation). An FPC (Flexible printed circuits) manufactured by Nippon Mektron Ltd. was attached thereto to produce a transparent conductive film. Next, the transparent conductive film was attached to an injection molding die, and a base material made of polycarbonate resin (PC) (manufactured by Covestro) was poured into the injection molding die. The temperature of the polycarbonate resin (PC) at this time was about 200 degrees. In this way, by insert molding, a molded body of Comparative Example 1 in which a transparent conductive film was adhered on a 3-mm thick base material (150 mm × 150 mm) made of polycarbonate resin (PC) was obtained.

[0071] [Comparative Example 2] As the thin film member, a 20-μm-thick film (50 mm × 100 mm) made of polyethylene terephthalate (PET) was used. Copper nanoparticles (manufactured by Taiyo Nisso Co., Ltd.) were used as the material, and a plurality of metal wirings with a wire diameter of 6 μm were formed on the thin film member in parallel at intervals of 2 mm using an R&D inkjet device (manufactured by Seiko Epson Corporation). An FPC (Flexible printed circuits) manufactured by Nippon Mektron Ltd. was attached thereto to fabricate a transparent conductive film. Next, the transparent conductive film was attached to an injection molding die, and a base material of polycarbonate resin (PC) (Makrolon manufactured by Covestro) was poured into the injection molding die. The temperature of the polycarbonate resin (PC) at this time was about 200 degrees. In this way, by insert molding, a molded body of Comparative Example 2 in which a transparent conductive film was adhered onto a 3-mm-thick base material (150 mm × 150 mm) made of polycarbonate resin (PC) was obtained.

[0072] (Evaluation of Wiring Disturbance) The molded bodies of Examples 1 to 5 or the molded bodies of Comparative Examples 1 and 2 were observed with a KEYENCE VHX-8000 microscope to evaluate the disturbance of the metal wiring in five grades from A to E. The evaluation was set as A when there was no wiring disturbance, B when there were partial defects less than 10% of the wiring, C when there were defects from 10% to 30% of the wiring, D when there were defects in about half of the wiring, and E when there were defects in half to the entire surface. Fig. 5 summarizes the evaluation results of the wiring disturbance of Examples 1 to 5 and Comparative Examples 1 and 2.

[0073] (Evaluation of Curing Shrinkage) The shrinkage (warpage) of the molded bodies of Examples 1 to 5 or the molded bodies of Comparative Examples 1 and 2 during curing was evaluated in five grades from A to E by measuring the dimensional change rate in the height direction of the molded bodies. The evaluation was set as A when there was no dimensional change (0% or more and less than ±3%), B when it was ±3% or more and less than ±5%, C when it was ±5% or more and less than ±10%, D when it was ±10% or more and less than ±15%, and E when it was ±15% or more. Fig. 5 summarizes the evaluation results of the curing shrinkage of Examples 1 to 5 and Comparative Examples 1 and 2.

[0074] (Boundary evaluation) The boundaries between the transparent conductive films and the substrates in Molded Bodies of Examples 1 to 5 or Molded Bodies of Comparative Examples 1 and 2 were evaluated visually at five levels from A to E. The evaluation was defined as A when the boundary was not visible, B when less than 10% of the boundary was visible, C when 10% or more but less than 30% of the boundary was visible, D when 30% or more but less than 50% of the boundary was visible, and E when more than half of the boundary was visible. Fig. 5 summarizes the evaluation results of the boundaries between the transparent conductive films and the substrates in Examples 1 to 5 and Comparative Examples 1 and 2.

[0075] (Visible light transmittance evaluation) The visible light transmittance of the Molded Bodies of Examples 1 to 5 or Molded Bodies of Comparative Examples 1 and 2 was evaluated by measuring the transmittance of visible light at 440 nm using a spectrophotometer (manufactured by Shimadzu Corporation). The evaluation was defined as A when the transmittance was 90 or more, B when the transmittance was 85% or more but less than 90%, C when the transmittance was 80% or more but less than 85%, D when the transmittance was 75% or more but less than 80%, and E when the transmittance was less than 75%. Fig. 5 summarizes the evaluation results of the visible light transmittance of Examples 1 to 5 and Comparative Examples 1 and 2.

[0076] (Infrared transmittance evaluation) The infrared transmittance of the Molded Bodies of Examples 1 to 5 or Molded Bodies of Comparative Examples 1 and 2 was evaluated by measuring the transmittance of infrared light at 900 nm using a spectrophotometer (manufactured by Shimadzu Corporation). The evaluation was defined as A when the transmittance was 85% or more, B when the transmittance was 80% or more but less than 85%, C when the transmittance was 75% or more but less than 80%, D when the transmittance was 70% or more but less than 75%, and E when the transmittance was less than 70%. Fig. 5 summarizes the evaluation results of the infrared transmittance of Examples 1 to 5 and Comparative Examples 1 and 2.

[0077] (Millimeter wave transmittance evaluation) The molded articles of Examples 1 to 5 or the molded articles of Comparative Examples 1 and 2 were placed in a box surrounded by a radio wave absorber, and the S21 was measured using a millimeter-wave signal light source and a vector network analyzer. The frequency was set to 76.5 GHz to evaluate the transmittance of millimeter waves. The evaluation was as follows: A when the transmittance was 85% or more, B when the transmittance was 80% or more and less than 85%, C when the transmittance was 75% or more and less than 80%, D when the transmittance was 70% or more and less than 75%, and E when the transmittance was less than 70%. Fig. 5 shows the summarized results of the millimeter-wave transmittance evaluations of Examples 1 to 5 and Comparative Examples 1 and 2.

[0078] As is clear from Fig. 5, in the molded articles according to Examples 1 to 5, since the anti-fog coating composition is cured by ultraviolet rays and the transparent conductive film is fixed to the substrate, there is no wiring disorder in the metal wiring formed on the thin film member of the transparent conductive film, and visible light and infrared rays are transmitted. That is, a visible light monocular camera and an infrared LiDAR (sensor) can be incorporated inside the substrate. Also, on the hard coat side (outer surface side of the substrate), active snow melting can be achieved by applying a voltage to the metal wiring. Furthermore, by disposing the transparent conductive film on the optical path of the light emitted from the sensor, on the anti-fog film side (inner surface side of the substrate), anti-fogging can be actively performed in front of the sensor, and an anti-fogging effect can be obtained by the anti-fog film for portions not in front of the sensor. That is, the reliability of the ADAS sensor can be improved.

[0079] As shown by the fact that the evaluation of the curing shrinkage of the molded articles according to Examples 2 to 5 containing 5% or more of the thiol material in the anti-fog composition is B or more, the curing shrinkage of the molded articles is suppressed. Also, in the molded articles according to Examples 2 to 5, the transmittance of millimeter waves is improved by making the wiring pattern of the metal wiring a parallel wiring. By improving the transmittance of millimeter waves, it becomes possible to incorporate a millimeter-wave radar inside the substrate.

[0080] In Example 3, where both the material of the thin film member and the material of the base material are polycarbonate resin (PC), the refractive indices of the thin film member and the base material are the same, resulting in an A evaluation in the evaluation of the boundary. Therefore, the boundary between the thin film member and the base material is not visible, improving the appearance.

[0081] As shown by the evaluation results of the molded body according to Example 4, even when polymethyl methacrylate resin (PMMA) is used as the material of the base material, sufficient light transmittance in visible light, infrared rays, and millimeter waves can be obtained.

[0082] As shown by the fact that the evaluation of the cured shrinkage of the molded body according to Example 5, which contains 20% or more of a thiol material in the anti-fogging composition, is grade A, the cured shrinkage can be significantly suppressed.

[0083] As described above, according to the optical unit of the present invention, the light transmittance of the base material can be ensured by achieving both a snow melting effect and an anti-fogging effect.

Explanation of Reference Numerals

[0084] 10 Optical unit 11 Housing 12 Base material 13 First optical device 14 Second optical device 15 Anti-fogging film 16 Hard coat 17 Transparent conductive film 18 Thin film member 19 Metal wiring 20 First contact 21 Second contact

Claims

1. A housing, a light-transmissive base material, and an optical device disposed in an internal space defined by the housing and the base material, an anti-fog film formed on an inner surface of the base material in at least a region corresponding to a path of light emitted from the optical device, and an optical unit including a transparent conductive film provided in contact with the anti-fog film and generating heat when power is supplied.

2. The optical unit according to claim 1, wherein at least a part of the transparent conductive film is embedded in the anti-fog film.

3. The transparent conductive film has a thin film member and metal wiring formed on the thin film member, and the base material and the thin film member are formed of a light-transmissive material having the same dielectric constant. The optical unit according to claim 1.

4. The optical unit according to claim 1, wherein the transmittance of at least one of infrared rays, visible light, and millimeter waves of the transparent conductive film is 80% or more.

5. The anti-fog film is composed of a cured film obtained by curing an active energy ray-curable anti-fog composition containing a radical-reactive material and a thiol material, and in the anti-fog composition, the content of the radical-reactive material is 70 to 95%, and the content of the thiol material is 5 to 10%. The optical unit according to claim 1.

6. The optical unit according to claim 1, which is a vehicle headlight unit having a light-emitting device as the optical device.

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