Camera cover and imaging device, and method for manufacturing a camera cover

Abstract

To obtain a camera cover that is easy to manufacture, highly scratch-resistant, and suitable for long-term outdoor installation. [Solution] A dome-shaped camera cover protects the imaging unit. The surface of the camera cover is coated with a urethane acrylate resin. The Berkovich hardness of the coating surface at an indenter penetration depth of 100-300 nm is 0.4 GPa or higher.

Description

[Technical Field]

[0001] The present invention relates to a camera cover, an imaging device, and a method for manufacturing a camera cover, and more particularly to a camera cover for a surveillance camera installed outdoors. [Background technology]

[0002] Surveillance cameras are widely used as security systems in residential or commercial buildings, or outdoors. Surveillance cameras are equipped with transparent camera covers to protect them from rainwater or gravel. Camera covers can be scratched by flying sand or by maintenance due to dirt and dust, and scratches on the camera cover can degrade the captured image.

[0003] Therefore, a technique is known to make camera covers more scratch-resistant by applying a coating. For example, Patent Document 1 discloses a hard coat made of silicone resin. Patent Document 2 also discloses a hard coat made of urethane acrylate resin. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-255917 [Patent Document 2] Japanese Patent Publication No. 2009-62423 [Overview of the project] [Problems that the invention aims to solve]

[0005] The hard coat made of the silicone resin described in Patent Document 1 has problems that cracks may occur after film formation and that the cost is high because long-time baking is required. The hard coat made of the urethane acrylate resin described in Patent Document 2 has advantages that cracks are less likely to occur and that it can be easily cured by short-time baking and light irradiation, but has a problem that the abrasion resistance is not sufficient.

[0006] An object of the present invention is to obtain a camera cover that is easy to manufacture, has high abrasion resistance, and is suitable for long-term outdoor installation.

Means for Solving the Problems

[0007] In order to achieve the object of the present invention, a camera cover according to an embodiment of the present invention has the following configuration. That is, A dome-shaped camera cover that protects an imaging unit, A coating containing a urethane acrylate resin is formed on the surface of the camera cover, The Vickers hardness at an indentation depth of 100 to 300 [nm] of the indenter on the surface of the coating is 0.4 [GPa] or more.

Effects of the Invention

[0008] It is possible to obtain a camera cover that is easy to manufacture, has high abrasion resistance, and is suitable for long-term outdoor installation.

Brief Description of the Drawings

[0009] [Figure 1] An outline view of an imaging device according to an embodiment. [Figure 2] An explanatory view of a camera cover according to an embodiment. [Figure 3] A partial cross-sectional view of a camera cover portion according to an embodiment. [Figure 4] A diagram for explaining a light irradiation method for photocuring. [Figure 5] A diagram for explaining a light irradiation method for photocuring. [Figure 6] A diagram for explaining a light irradiation method for photocuring. [Figure 7] A diagram for explaining a light irradiation method for photocuring. [Figure 8] A flowchart of a method for manufacturing a camera cover according to an embodiment. [Figure 9] A diagram showing the relationship between the Vickers hardness and the haze value.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0011] FIG. 1 is a schematic diagram of an imaging device 10 according to an embodiment of the present invention. The imaging device 10 shown in FIG. 1 includes a camera unit 100, a data transfer unit 120, a data storage unit 121, and a controller 122. The video captured by the camera unit 100 can be transferred to a network via the controller 122 and the data transfer unit 120. Further, the video captured by the camera unit 100 can be transferred to the data storage unit 121 via the controller 122 and stored in the data storage unit 121. The data transfer unit 120, the data storage unit 121, and the controller 122 are covered by an exterior 130 for protection from external impacts and for preventing the intrusion of moisture.

[0012] Furthermore, in one embodiment of the present invention, the camera unit 100 is covered by a camera cover 110. The camera cover 110 according to this embodiment is a dome-shaped camera cover that protects the imaging unit, and a coating 1500 containing urethane acrylate resin is formed on its surface. Such a camera cover 110 can protect the camera unit 100 from external impacts and the intrusion of moisture. The specific shape of the camera cover 110 is not particularly limited. For example, the camera cover 110 may have an outer wall and an opening, and the outer wall may define an internal space that communicates with the opening. In this case, as shown in Figure 1, the camera unit 100 can be housed in the internal space of the camera cover 110, and the camera unit 100 can be protected by closing the opening with a member such as an exterior casing 130. In one embodiment, the camera cover 110 has a generally hemispherical shape.

[0013] Figure 2 is a cross-sectional view showing an example of a camera cover 110. The camera cover 110 has a substantially hemispherical portion 1101 in the center. A base portion 1102 is present near the end of the substantially hemispherical portion 1101, and a flange 1103 is provided at the end. The camera cover 110 can be attached to the outer casing 130 by fixing the flange 1103 to the outer casing 130 with screws via an O-ring. In the example in Figure 2, the coating 1500 can be formed on the entire dome 140, including the outer surface of the spherical part of the substantially hemispherical portion 1101.

[0014] The camera cover 110 has a dome 140, which is a dome-shaped camera cover base material, and a coating 1500 formed on its surface. To enable imaging by the camera unit 100, the dome 140 is made of a transparent resin material. The type of dome 140 is not particularly limited, but it may be made of polycarbonate resin, acrylic resin, or polyester resin. In one embodiment, a dome 140 made of polycarbonate resin, which is resistant to impact, is used. For example, the material constituting the dome 140 may include polycarbonate, or 50% or 90% (by weight) or more of the material constituting the dome 140 may be polycarbonate. Alternatively, the dome 140 may be substantially made of polycarbonate.

[0015] Figure 3 is a partial cross-sectional view of a camera cover 110 according to one embodiment. As shown in Figure 3, a coating 1500 is formed on the surface of the camera cover 110. In this embodiment, the coating 1500 is a coating containing urethane acrylate resin. The coating containing urethane acrylate resin used in this embodiment is hard and resistant to scratches, and can therefore be called a hard coat. Since urethane acrylate resin can be photocured (ultraviolet curing), the coating 1500 can be formed at low cost. Furthermore, by using a urethane acrylate resin with a short drying time during application, the coating 1500 can be formed at an even lower cost.

[0016] Urethane acrylate resin refers to a resin having urethane bonds and acrylic groups (including methacrylic groups), or a resin obtained by photocuring this resin. Urethane acrylate resin can be obtained, for example, by reacting a compound having acrylic groups (including methacrylic groups) and hydroxyl groups, a polyisocyanate compound (including polyisocyanurate), and, if necessary, a polyol.

[0017] The type of urethane acrylate resin is not particularly limited, but in one embodiment, an aliphatic urethane acrylate resin is used. An aliphatic urethane acrylate resin refers to a urethane acrylate resin obtained by using aliphatic diisocyanate as the isocyanate constituent unit. Aliphatic urethane acrylate resins are less prone to yellowing in weathering tests, thus improving the weather resistance of the camera cover. In one embodiment, in order to improve the weather resistance of the camera cover, a urethane acrylate resin that does not contain a benzene ring as a constituent unit is used.

[0018] Examples of urethane acrylate resins include urethane acrylate oligomers obtained by reacting (meth)acrylate and polyisocyanate, as described in Japanese Patent Publication No. 2009-62423, or cured versions thereof.

[0019] Furthermore, to promote the photocuring of the urethane acrylate resin, the urethane acrylate resin may contain a photoradical polymerization initiator. The type of photoradical polymerization initiator is not particularly limited, but examples include α-hydroxyalkylphenones such as 1-hydroxycyclohexylphenyl ketone or benzophenones.

[0020] In this embodiment, the Berkovich hardness of the coating 1500 surface at an indenter penetration depth of 100-300 nm is 0.4 GPa or higher. In this specification, Berkovich hardness can be measured by nanoindentation using a Berkovich diamond indenter in accordance with ISO 14577-1:2015 and ISO 14577-4:2016. Since the film thickness of the coating 1500 is often around 2 μm to 10 μm, the indenter penetration depth is set to 100-300 nm, which is about 1 / 10 of the film thickness, in order to obtain physical property values ​​that do not include the characteristics of the substrate. As will be described later, the inventors of this application have found that by setting the Berkovich hardness to 0.4 GPa or higher, sufficient scratch resistance for the coating 1500 as an optical component can be obtained. Furthermore, by setting the Berkovich hardness to 0.45 [GPa] or higher, excellent abrasion resistance can be obtained, and by setting the Berkovich hardness to 0.55 [GPa] or higher, extremely excellent abrasion resistance can be obtained.

[0021] Furthermore, in one embodiment, the surface of coating 1500 exhibits a change in haze value of 10% or less when abrasion resistance is evaluated by the following method. In the abrasion resistance evaluation described herein, a sample cut from the camera cover 110 is rubbed with steel wool (steel wool roughness #1000, load 2000g, 5 back-and-forth strokes), and the difference in haze value of the rubbed portion before and after rubbing can be measured. In this specification, the haze value can be measured in accordance with JIS K7136:2000. If the change in haze value is 5% or less, coating 1500 is considered to have very good abrasion resistance; if the change is greater than 5% and 7% or less, it is considered to have good abrasion resistance; and if the change is greater than 7% and 10% or less, it is considered to have practically sufficient abrasion resistance.

[0022] In one embodiment, the film thickness of the coating 1500 can be 2 [μm] or more so that the function of the coating 1500 is fully exhibited. In another embodiment, the film thickness of the coating 1500 can be 10 [μm] or less in order to suppress optical effects.

[0023] In this specification, the measurement of Berkovich hardness and the evaluation of abrasion resistance can be performed on the top and peripheral portions of the camera cover 110. For example, the measurement and evaluation can be performed on the central and lower portions 1102 of the approximately hemispherical portion 1101. If the Berkovich hardness is above a predetermined value in both the top and peripheral portions of the camera cover 110, it can be determined that the Berkovich hardness of the camera cover 110 is above the predetermined value. Similarly, if the change in haze value is below a predetermined value in both the top and peripheral portions of the camera cover 110, it can be determined that the change in haze value of the camera cover 110 is below the predetermined value. The hardness and abrasion resistance of the peripheral portion of the camera cover 110 can be measured and evaluated at one point or multiple points at the edge of the imaging range of the camera portion 100 on the outer surface of the camera cover 110. The same applies to the measurement of film thickness.

[0024] Furthermore, as will be described later, since the hardness of coating 1500 depends on the amount of light during curing, the Berkovich hardness measurement and abrasion resistance evaluation may be performed on the area with the weakest irradiation light. In this case, if the Berkovich hardness in this area is above a predetermined value, and the change in the haze value is below a predetermined value, it can be determined that the Berkovich hardness of the camera cover 110 is above a predetermined value, and the change in the haze value is below a predetermined value.

[0025] In one embodiment, the Berkovich hardness of the entire outer surface of the camera cover 110 that is included in the imaging range of the camera unit 100 is 0.4 [GPa] or higher, 0.45 [GPa] or higher, or 0.55 [GPa] or higher. In another embodiment, the Berkovich hardness of the entire outer surface of the camera cover 110 is 0.4 [GPa] or higher, 0.45 [GPa] or higher, or 0.55 [GPa] or higher.

[0026] Next, a method for manufacturing the camera cover 110 by forming a coating 1500 will be described with reference to Figure 8. In S1010, a urethane acrylate resin coating solution is prepared. As the coating solution, a coating solution containing a urethane acrylate oligomer can be used. Here, the viscosity of the coating solution may be adjusted to change the thickness of the coating 1500 based on the relationship between surface tension and viscosity. By adjusting the viscosity of the coating solution, it is possible to ensure a sufficient film thickness to obtain the function of the coating 1500 while suppressing optical effects caused by the coating 1500 being too thick.

[0027] In S1020, a coating film is formed on the dome 140 by applying the coating solution prepared in S1010. The application apparatus and method for the coating solution are not particularly limited, but in this embodiment, spin coating using a spin coater is performed in order to apply the coating more uniformly to the dome 140 which has a three-dimensional shape. However, other methods such as dip coating or spray coating may also be used.

[0028] In S1030, the coating film applied in S1020 is cured. Since the urethane acrylate resin is a photocurable resin, the coating film can be cured by light irradiation. In this embodiment, the organic solvent is scattered from the coating film by heating and drying, and then the coating 1500 can be fixed by irradiation with ultraviolet light. The heating method is not particularly limited, and a method of maintaining the object to be heated at a specified temperature using a hot air furnace, electric furnace, far-infrared furnace, or near-infrared furnace can be used.

[0029] Furthermore, the light source is not particularly limited, and for example, an ultraviolet lamp such as a mercury lamp can be used. Incidentally, as shown in the embodiments described later, the inventors of this application have found that the hardness of coating 1500 depends on the amount of light irradiation. In one embodiment, in order to obtain practically sufficient abrasion resistance of coating 1500, the integrated light amount is 2000 [mJ / mm²]2 Light irradiation is performed so that the total light intensity is 2400 [mJ / mm²] or higher. In addition, in order to obtain excellent abrasion resistance, the total light intensity is 2400 [mJ / mm²]. 2 Light irradiation can be performed to a level of 3000 [mJ / mm²] or higher, and in order to obtain extremely excellent abrasion resistance, the integrated light intensity is 3000 [mJ / mm²]. 2 Light irradiation can be performed so as to be above ].

[0030] Furthermore, in one embodiment, in order to obtain practically sufficient abrasion resistance of coating 1500, the illuminance is 140 [mW / mm²]. 2 Light irradiation is performed so that the illuminance is 170 [mW / mm²] or higher. In addition, in order to obtain excellent scratch resistance, the illuminance is 170 [mW / mm²]. 2 Light irradiation can be performed to achieve a value of 220 [mW / mm²] or higher, and in order to obtain extremely excellent scratch resistance, the illuminance should be 220 [mW / mm²]. 2 Light irradiation can be performed so as to be above ].

[0031] Furthermore, similar to the measurement of Berkovich hardness, light irradiation may be performed so that the integrated light quantity or illuminance at the top and periphery of the camera cover 110 is equal to or greater than a predetermined value. Alternatively, light irradiation may be performed so that the integrated light quantity or illuminance at the weakest illuminated area is equal to or greater than a predetermined value. In addition, light irradiation may be performed so that the integrated light quantity or illuminance at the entire outer surface of the camera cover 110 that is included in the imaging range of the camera unit 100 is equal to or greater than a predetermined value. Alternatively, light irradiation may be performed so that the integrated light quantity or illuminance at the entire outer surface of the camera cover 110 is equal to or greater than a predetermined value.

[0032] The method of light irradiation is not particularly limited. However, by irradiating light from multiple positions, it is possible to irradiate the camera cover 110, which has a complex three-dimensional shape, more uniformly, making it easier to provide sufficient abrasion resistance to the entire camera cover 110. From this viewpoint, light can be irradiated onto the camera cover 110 from two or more or three or more positions. For example, multiple light sources may be arranged, and light may be irradiated onto the camera cover 110 from each light source. Alternatively, light may be irradiated onto the camera cover 110 from a movable light source. In this case, by fixing the light source to a movable member such as a robot arm and controlling the position of the movable member, light can be irradiated onto the camera cover 110 from multiple positions using a single light source. [Examples]

[0033] (Example 1) The coating solution was prepared by mixing the Z-700W-7 coating solution concentrate (manufactured by Aica Kogyo Co., Ltd.) with an organic solvent. The Z-700W-7 coating solution concentrate contains urethane acrylate obtained from aliphatic diisocyanate. As the organic solvent, 1-methoxy-2-propanol (manufactured by Kishida Chemical Co., Ltd.), one of the components of the Z-700W-7 coating solution concentrate, was used to adjust the viscosity.

[0034] Subsequently, the obtained coating solution was applied to the dome using a spin coater, dried, and then UV cured to produce a camera cover. An MS-B300 (manufactured by Mikasa Corporation) was used as the spin coater. As shown in Figure 4, 10 mL of the coating solution was applied from the zenith of the dome using a nozzle, and the spin coater was operated at a rotation speed of 200 rpm and a rotation time of 30 seconds. This allowed the coating solution to spread to the bottom, resulting in uniform coating of the entire dome. Drying was performed by heating in a circulating hot air furnace at 86°C ± 5°C for 5 minutes.

[0035] The method of ultraviolet curing is shown in Fig. 4. In this embodiment, a high-pressure mercury lamp unit 2000 was installed above the belt conveyor 2002. Then, with the light of one high-pressure mercury lamp 2001 hitting the dome 140 from above, the dried dome 140 was placed on the belt conveyor 2002 and passed under the high-pressure mercury lamp. Here, an air-cooled mercury lamp H08-L41 (manufactured by Iwasaki Electric Co., Ltd.) was used as the mercury lamp. Also, in order to measure the illuminance of ultraviolet rays, ultraviolet rays with a wavelength of 254 [nm] were measured using an ultraviolet integrated light quantity meter UIT-250 (manufactured by Ushio Electric Co., Ltd.). The illuminance of ultraviolet rays was measured by fixing the sensor part of the integrated light quantity meter in the direction of the light of the high-pressure mercury lamp and moving it on the belt conveyor. In this configuration, the irradiation light to the skirt portions on the left and right of the dome 140 with respect to the belt traveling direction became the weakest. Therefore, the illuminance at this portion became 100 [mW / mm 2 , and the illuminance of the mercury lamp and the irradiation time were adjusted so that the integrated light quantity became 800 [mJ / mm 2 . Note that the illuminance of 100 [mW / mm 2 and the integrated light quantity of 800 [mJ / mm 2 are the curing conditions recommended by the coating liquid manufacturer. Since the coating liquid contains α-hydroxyalkylphenone, which is a photoinitiator, polymerization proceeds by ultraviolet irradiation, and the coating liquid is cured and fixed. Here, the curing of the coating liquid was promoted by a photoradical polymerization reaction.

[0036] The abrasion resistance of the obtained coating was evaluated. In this embodiment (and the following embodiments), the abrasion resistance of the portion where the irradiation light was the weakest (in this embodiment, the skirt portions on the left and right with respect to the belt traveling direction) was evaluated. Specifically, a sample cut out from the camera cover was rubbed with steel wool (steel wool roughness #1000, load 2000 g, back and forth 5 times), and the change in haze value before and after rubbing at the rubbed portion was measured. A haze meter HM-150L2N (manufactured by Murakami Color Technology Laboratory Co., Ltd.) was used to measure the haze value. The obtained haze change was 30%, and it was evaluated that the abrasion resistance was insufficient as a coating film for optical components.

[0037] Furthermore, the Birkovich hardness of the obtained coating was measured. In this example (and the following examples), the Birkovich hardness was measured in the area where the irradiated light was weakest (in this example, the lower edges on the left and right sides relative to the direction of belt travel). The Birkovich hardness was measured by the nanoindentation method using NanoIndentaerG200 (manufactured by KLA Corporation). A Birkovich diamond indenter was used as the indenter. The obtained Birkovich hardness was 0.25 [GPa].

[0038] (Example 2) Except for the method of ultraviolet irradiation, a camera cover was manufactured in the same manner as in Example 1, and its abrasion resistance and Berkovich hardness were measured. The method of ultraviolet curing in this example is shown in Figure 5. In this example, high-pressure mercury lamp units 2000 were installed on the left and right sides of the belt conveyor 2002 in the direction of travel. Then, with light from each of the two high-pressure mercury lamps 2001 shining on the dome 140 from the left and right, the dried dome 140 was placed on the belt conveyor 2002 and passed through the installation positions of the high-pressure mercury lamps 2001. In this configuration, the light irradiation to the zenith of the dome 140 was weakest, and the illuminance at this part was 127 [mW / mm²]. 2 ], the total luminous intensity is 1777 [mJ / mm²]. 2 The results were as follows. Furthermore, for this portion of the camera cover obtained, the haze change obtained in the abrasion resistance evaluation test was 15.3%, and the Berkovich hardness was 0.36 [GPa].

[0039] (Example 3) Except for the method of ultraviolet irradiation, a camera cover was manufactured in the same manner as in Example 1, and its abrasion resistance and Berkovich hardness were measured. The method of ultraviolet curing in this example is shown in Figure 6. In this example, a high-pressure mercury lamp unit 2000 was installed above the belt conveyor 2002, and further high-pressure mercury lamp units 2000 were installed on the left and right sides in the direction of travel of the belt conveyor 2002. Then, with light from each of the three high-pressure mercury lamps 2001 shining on the dome 140 from above and from the left and right, the dried dome 140 was placed on the belt conveyor 2002 and passed through the installation positions of the high-pressure mercury lamps 2001. In this configuration, the light irradiation to the lower part of the dome 140 on the left and right sides in the direction of travel of the belt was weakest, and the illuminance at that part was 135 [mW / mm²]. 2 ], the total luminous intensity is 1886 [mJ / mm²] 2 The results were as follows. Furthermore, for this portion of the camera cover obtained, the haze change obtained in the abrasion resistance evaluation test was 10.8%, and the Berkovich hardness was 0.38 [GPa].

[0040] (Example 4) Except for the illuminance and cumulative intensity of ultraviolet light, a camera cover was fabricated in the same manner as in Example 3, and its abrasion resistance and Berkovich hardness were measured. In this configuration, the light irradiated to the lower edges of the dome 140 on both sides relative to the direction of belt travel was weakest, and the illuminance at that point was 143 [mW / mm²]. 2 ], the total light intensity is 2001 [mJ / mm 2 Furthermore, for this portion of the camera cover obtained, the haze change obtained in the abrasion resistance evaluation test was 10%, and the Berkovich hardness was 0.40 [GPa].

[0041] (Example 5) Except for the method of ultraviolet irradiation, a camera cover was manufactured in the same manner as in Example 1, and its abrasion resistance and Berkovich hardness were measured. The method of ultraviolet curing in this example is shown in Figure 7. In this example, a high-pressure mercury lamp unit 2000 was installed above the belt conveyor 2002 via a 6-axis articulated robot 2003. Then, while moving the position of the high-pressure mercury lamp unit 2000, the dried dome 140 was placed on the belt conveyor 2002 and passed through the installation position of the high-pressure mercury lamp 2001. At this time, the 6-axis articulated robot 2003 was driven so that light from one high-pressure mercury lamp 2001 struck the dome 140 from the left and right sides relative to the direction of belt travel. With this configuration, irradiation from two directions made it possible to irradiate the dome 140 with almost uniform light. The average illuminance at the top of the dome 140, where the irradiation light was weakest in the obtained camera cover, was 156 [mW / mm²]. 2 ], the total luminous intensity is 2188 [mJ / mm²]. 2 Furthermore, the haze change obtained in the abrasion resistance evaluation test for this portion was 8.9%, and the Berkovich hardness was 0.43 [GPa].

[0042] (Example 6) Except for the method of ultraviolet irradiation, a camera cover was fabricated in the same manner as in Example 5, and its abrasion resistance and Berkovich hardness were measured. In this example, a 6-axis articulated robot 2003 was driven so that light from a single high-pressure mercury lamp 2001 struck the dome 140 from above, and from the left and right sides relative to the direction of belt travel. With this configuration, irradiation from three directions allowed for nearly uniform illumination, and the average illuminance was 161 [mW / mm²]. 2 ], the total luminous intensity is 2254 [mJ / mm²]. 2 Furthermore, in the camera cover obtained, the haze change obtained in the scratch resistance evaluation test for the zenith portion of dome 140, where the illumination light was weakest, was 8.3%, and the Berkovich hardness was 0.44 [GPa].

[0043] (Example 7) Except for the method of ultraviolet irradiation, a camera cover was manufactured in the same manner as in Example 5, and its abrasion resistance and Berkovich hardness were measured. In this example, a 6-axis articulated robot 2003 was driven so that light from a single high-pressure mercury lamp 2001 struck the dome 140 from above, and from the left and right sides relative to the direction of belt travel. With this configuration, the irradiation from three directions made it possible to irradiate the dome 140 with light almost uniformly. In the obtained camera cover, the average illuminance at the zenith of the dome 140, where the irradiation light was weakest, was 161 [mW / mm²]. 2 ], the total luminous intensity is 2254 [mJ / mm²]. 2 Furthermore, the haze change obtained in the abrasion resistance evaluation test for this portion was 7.8%, and the Berkovich hardness was 0.44 [GPa].

[0044] (Example 8) Except for the ultraviolet illuminance and integrated light quantity, a camera cover was fabricated in the same manner as in Example 6, and its abrasion resistance and Berkovich hardness were measured. In this configuration, the illumination light could be irradiated almost uniformly. In the obtained camera cover, the average illuminance at the zenith of dome 140, where the illumination light was weakest, was 176 [mW / mm²]. 2 ], the total luminous intensity is 2464 [mJ / mm²]. 2 Furthermore, the haze change obtained in the abrasion resistance evaluation test for this portion was 6.9%, and the Berkovich hardness was 0.47 [GPa].

[0045] (Example 9) Except for the ultraviolet illuminance and integrated light quantity, a camera cover was fabricated in the same manner as in Example 6, and its abrasion resistance and Berkovich hardness were measured. In this configuration, the illumination light could be irradiated almost uniformly. In the obtained camera cover, the average illuminance at the zenith of dome 140, where the illumination light was weakest, was 204 [mW / mm²]. 2 ], the total luminous intensity is 2859 [mJ / mm²]. 2 Furthermore, the haze change obtained in the abrasion resistance evaluation test for this portion was 5.7%, and the Berkovich hardness was 0.5 [GPa].

[0046] (Example 10) Except for the ultraviolet illuminance and integrated light quantity, a camera cover was fabricated in the same manner as in Example 6, and its abrasion resistance and Berkovich hardness were measured. In this configuration, the illumination light could be irradiated almost uniformly. In the obtained camera cover, the average illuminance at the zenith of dome 140, where the illumination light was weakest, was 349 [mW / mm²]. 2 ], the total luminous intensity is 4883 [mJ / mm²]. 2 Furthermore, the haze change obtained in the abrasion resistance evaluation test for this portion was 2.1%, and the Berkovich hardness was 0.7 [GPa].

[0047] The table below summarizes the illuminance and integrated light quantity in Examples 1 to 10. As mentioned above, each example differs in ultraviolet irradiation conditions, i.e., the direction of the light, as well as the illuminance and irradiation time. The illuminance and integrated light quantity differ depending on the part of the dome, but the table below shows the illuminance and integrated light quantity for the part where the integrated light quantity is minimum. [Table 1]

[0048] Figure 9 also shows the relationship between the change in haze value and Berkovich hardness measured in each example. In Figure 9, the vertical axis represents the change in haze value in the abrasion resistance evaluation, and the horizontal axis represents Berkovich hardness. For reference, Figure 9 also shows the results of the abrasion resistance evaluation and the measurement results of Berkovich hardness performed similarly on the silicone resin disclosed in Patent Document 1. For the silicone resin disclosed in Patent Document 1, the change in haze value obtained in the abrasion resistance evaluation test was 15%, and the Berkovich hardness was 0.34 [GPa].

[0049] As shown in Figure 9, a correlation was found between the change in haze value in the abrasion resistance evaluation test and Berkovich hardness. Specifically, it was found that the higher the Berkovich hardness, the smaller the change in haze value in the abrasion resistance evaluation. From this result, it was found that abrasion resistance can be estimated by Berkovich hardness. In particular, when the Berkovich hardness was 0.4 GPa or higher, the change in haze value in the abrasion resistance test was 10% or less, confirming that sufficient abrasion resistance for practical use as an optical component was obtained. Furthermore, when the Berkovich hardness was 0.45 GPa or higher, the change in haze value in the abrasion resistance test was 7% or less, confirming that excellent abrasion resistance was obtained. Moreover, when the Berkovich hardness was 0.55 GPa or higher, the change in haze value in the abrasion resistance test was 5% or less, confirming that extremely excellent abrasion resistance was obtained.

[0050] Furthermore, the cumulative light intensity is 2000 [mJ / mm²] 2 It was found that by irradiating with light to a level of 2400 [mJ / mm²] or higher, the Berkovich hardness could be increased to 0.4 GPa or higher. Furthermore, when the integrated light intensity was 2400 [mJ / mm²], 2 ] and above and 3000 [mJ / mm 2 It was found that by irradiating with light to achieve a hardness of 0.45 GPa or higher and 0.55 GPa or higher, the Birkovich hardness was achieved.

[0051] Also, the illuminance is 140 [mW / mm²] 2 It was found that by irradiating with light to a level of 170 [mW / mm²] or higher, the Berkovich hardness could be increased to 0.4 GPa or higher. Furthermore, when the illuminance was 170 [mW / mm²], 2 ] and above and 220 [mW / mm 2 It was found that by irradiating with light to achieve a hardness of 0.45 GPa or higher and 0.55 GPa or higher, the Birkovich hardness was achieved.

[0052] Furthermore, it was found that irradiating a coating applied to the surface of a component with a complex three-dimensional shape, such as a camera cover, from multiple positions, particularly from three or more positions, is effective. With this configuration, it becomes easy to perform photocuring so that the entire coating has sufficient hardness.

[0053] Based on the above results, by forming a coating containing urethane acrylate resin on the surface of the camera cover such that the Berkovich hardness is 0.4 [GPa] or higher, we were able to obtain a camera cover and imaging device that can achieve good abrasion resistance.

[0054] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0055] 10: Imaging device, 100: Camera unit, 110: Camera cover, 140: Dome, 1500: Coating

Claims

1. A dome-shaped camera cover that protects the imaging unit, The surface of the camera cover is coated with a urethane acrylate resin, A camera cover characterized in that the Berkovich hardness of the surface of the coating at an indenter penetration depth of 100 to 300 nm is 0.4 GPa or higher.

2. The camera cover according to claim 1, characterized in that the thickness of the coating is 2 [μm] or more and 10 [μm] or less.

3. The camera cover according to claim 1 or 2, characterized in that the urethane acrylate resin contains a photoradical polymerization initiator.

4. The camera cover according to claim 3, characterized in that the photoradical polymerization initiator is α-hydroxyalkylphenone.

5. The camera cover according to any one of claims 1 to 4, characterized in that the urethane acrylate resin is an aliphatic urethane acrylate resin.

6. The camera cover according to any one of claims 1 to 5, characterized in that the camera cover is made of polycarbonate resin.

7. A camera cover according to any one of claims 1 to 6, characterized in that the change in haze value before and after rubbing the surface of the coating five times back and forth with steel wool of coarseness #1000 under a load of 2000g is 10% or less.

8. Imaging unit, A camera cover according to any one of claims 1 to 7, provided to house the imaging unit, An imaging device characterized by comprising:

9. The process of preparing a urethane acrylate resin coating solution, The process involves applying the coating liquid to a dome-shaped camera cover substrate to form a coating film, The process of curing the aforementioned coating film, A method for manufacturing a camera cover, characterized in that the coating film, after curing, has a Berkovich hardness of 0.4 [GPa] or more at an indenter penetration depth of 100 to 300 [nm] on its surface.

10. In the process of curing the coating film, the integrated light amount with respect to the camera cover substrate is 2000 [mJ / mm²] ２ A method for manufacturing a camera cover according to claim 9, characterized in that light irradiation is performed so as to be above ].

11. A method for manufacturing a camera cover according to claim 9 or 10, characterized in that, in the step of curing the coating film, ultraviolet light is irradiated onto the camera cover substrate from multiple positions.

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