JP2020181073A - Lens with film, lens unit and camera module - Google Patents

Abstract

The present invention provides a lens with a film, a lens unit, and a camera module that can optimally adjust the height and pitch of the surface unevenness of a highly heat-resistant antireflection film and also improve the adhesion of the highly heat-resistant antireflection film. A film-coated lens 13 (14-17) of the present invention is provided in a lens barrel and has an antireflection film 30 formed on its surface. The anti-reflective film 30 is provided as a highly heat-resistant anti-reflective film, and the surface shape of the highly heat-resistant anti-reflective film 30 is controlled to improve the optical performance of the highly heat-resistant anti-reflective film 30 on the surface of the lens 13 (14-17). An uneven portion 80 for adjustment is provided. A water-repellent film 50A or a hydrophilic film 50B may be provided on the highly heat-resistant antireflection film 30. [Selection diagram] Figure 7

Description

The present invention particularly relates to a lens with a film, a lens unit, and a camera module provided in an in-vehicle camera mounted on a vehicle such as an automobile.

In recent years, in-vehicle cameras have been installed in automobiles to support parking and to prevent collisions by image recognition, and attempts have been made to apply them to automatic driving. In addition, a camera module such as an in-vehicle camera generally includes a lens group in which a plurality of lenses are arranged along an optical axis, a lens barrel for accommodating and holding the lens group, and at least one lens group. A lens unit having an aperture member arranged between lenses is provided (see, for example, Patent Document 1).

An antireflection film is generally provided on the surface of the lens constituting the lens unit in order to increase its transmittance, but especially when a resin lens is used as each lens constituting the lens group of the lens unit. Since the lens easily expands and contracts due to temperature changes, it is desired that the antireflection film is resistant to high temperatures and can follow the expansion and contraction (thermal deformation) of the lens.

Therefore, particularly in a resin lens, as an antireflection film, an antireflection film having extremely low reflectance and excellent heat resistance that can follow the thermal deformation of the lens (hereinafter, "high heat resistant reflection" in the present specification. An anti-reflective coating) may be used.

Japanese Unexamined Patent Publication No. 2013-231993

By the way, such a highly heat-resistant antireflection film is generally formed by coating, and its surface inevitably has an uneven shape due to its manufacturing method or the like. Such an uneven morphology of the surface can contribute to a decrease in reflectance and, in particular, a decrease in the angle of incidence dependence on light incident at an angle. That is, the uneven shape of the surface of the highly heat-resistant antireflection film makes it difficult to reflect light even when the incident angle of light fluctuates compared to a smooth surface (realizes an antireflection film with low incident angle dependence). To do). Specifically, the light incident on the high heat resistant antireflection film is taken into the high heat resistant antireflection film while repeating reflection in the uneven surface, and the reflection to the outside of the high heat resistant antireflection film is suppressed. ..

However, it is difficult to optimally adjust the height and pitch of the uneven shape of the surface of the highly heat-resistant antireflection film. Further, since the highly heat-resistant antireflection film is only bonded to the lens, which is the base material, by charging, it cannot be said that its adhesion is sufficient.

The present invention has been made in view of the above circumstances, and is a film capable of optimally adjusting the height and pitch of the surface uneven shape of the high heat resistant antireflection film and improving the adhesion of the high heat resistant antireflection film. It is an object of the present invention to provide a lens with a lens, a lens unit and a camera module.

In order to solve the above problems, the present invention is a lens with a film provided on a lens barrel and having an antireflection film formed on the surface thereof.
The antireflection film is provided as a highly heat-resistant antireflection film,
The surface of the lens is characterized by being provided with an uneven portion for controlling the surface shape of the high heat resistant antireflection film and adjusting the optical performance of the high heat resistant antireflection film.

In the above configuration, the "high heat resistant antireflection film" is formed between a plurality of inorganic particles having a volume ratio of 5 to 74% in the high heat resistant antireflection film and the adjacent inorganic particles, and has a volume ratio. An organic compound or an inorganic substance that binds the inorganic particles or the inorganic particles and the air layer to an air layer of 65% or less, has a younger ratio lower than that of the inorganic particles, and has a volume ratio of 5 to 95%. It comprises either a compound or an inorganic polymer. Alternatively, the "high heat resistant antireflection film" is made of a fine particle laminated thin film having voids, and the fine particle laminated thin film is bonded to the lens in a laminated state by alternately adsorbing the electrolyte polymer and the fine particles. By forming the antireflection film in such a form, the surface of the highly heat-resistant antireflection film inevitably has an uneven shape.

Compared to a smooth surface, such an uneven surface morphology reflects light even when the incident angle of light fluctuates (for example, when light is incident at an angle with respect to the optical axis). Make it difficult (to realize an antireflection film with low incident angle dependence). That is, the light incident on the high heat resistant antireflection film is taken into the high heat resistant antireflection film while being repeatedly reflected in the uneven surface, and the reflection to the outside of the high heat resistant antireflection film is suppressed.

Further, in such a highly heat-resistant antireflection film, the film thickness determined by the desired refractive index is 1 / of the wavelength λ of the visible light so that the phase of the reflected light and the phase of the incident light overlap each other and cancel each other out. By setting it to a multiple of 4 (for example, 100 nm), excellent antireflection characteristics can be realized.

That is, the highly heat-resistant antireflection film having the above configuration has an antireflection effect due to the uptake of light due to the uneven shape described above and an antireflection effect due to setting the film thickness to a multiple of 1/4 of the wavelength λ of visible light. Due to the synergistic effect with, it has excellent antireflection characteristics (high light transmittance) as compared with the conventional antireflection film. The highly heat-resistant antireflection film, in combination with this synergistic effect, is formed in the form of the above-mentioned composition of inorganic particles, air layer and compound, or the form of fine particle laminated thin film, thereby being flexible and flexible. It has properties and excellent heat resistance, and as a result, it is possible to prevent cracks in the highly heat-resistant antireflection film at high temperatures. In this case, in particular, since the air layer (void) is formed between adjacent inorganic particles, even if the lens on which the highly heat-resistant antireflection film is formed expands or contracts due to a temperature change, A highly heat-resistant anti-reflective coating can follow suit. Therefore, it is possible to prevent the highly heat-resistant antireflection film from being destroyed.

Conventionally, it has been difficult to optimally adjust the height and pitch of the uneven shape of the surface of the highly heat-resistant antireflection film that contributes to the excellent antireflection characteristics as described above, but according to the present invention having the above configuration. For example, the surface of the lens is provided with an uneven portion for controlling the surface shape of the high heat resistant antireflection film to adjust the optical performance of the high heat resistant antireflection film. It can affect the surface morphology. Specifically, for example, the surface morphology of the highly heat-resistant antireflection film can be changed to a shape corresponding to the shape of the uneven portion on the lens surface, and the surface of the highly heat-resistant antireflection film surface. The height and pitch of the uneven shape can be optimally adjusted by the uneven portion.

Therefore, if the uneven portion of the lens surface is formed to suit the desired optical conditions and the height and pitch of the uneven shape of the highly heat-resistant antireflection film are optimized, the reflectance and the angle of incidence depend on the desired degree. (For example, regarding the incident angle dependence, it is also possible to average and cancel the optical path difference between the linear light incident parallel to the optical axis and the oblique light forming an angle with respect to the optical axis. Will be). In addition, such uneven portions on the lens surface that can adjust the surface unevenness morphology of the high heat resistant antireflection film have high heat resistant reflection on the lens due to the anchor effect (engagement of the unevenness between the lens and the high heat resistant antireflection film). It is also possible to improve the adhesion of the preventive film.

As can be seen from the above, the uneven portion of the lens surface of the present invention in the above configuration makes it possible to adjust the height and pitch of the uneven form of the high heat resistant antireflection film, whereby the optical performance of the high heat resistant antireflection film can be adjusted. It is for adjusting. In other words, the uneven portion on the lens surface is for realizing the desired antireflection property in cooperation with the highly heat-resistant antireflection film, and does not itself have an optical function. Therefore, for example, the height (depth) of the uneven portion on the lens surface is set to 70 nm so as not to have an optical function by itself. However, the uneven portion on the lens surface may have an optical function by itself.

In the above configuration, the "lens surface" includes both the surface of the lens facing the object side and the surface of the lens facing the image side. Further, in the above configuration, the uneven portion on the lens surface may be formed by processing the uneven portion on the mold for molding the lens, for example, when the lens is made of resin, or when the lens is made of glass. May be formed on the surface of the lens by etching or the like.

Further, in the above configuration of the present invention, the surface of the highly heat-resistant antireflection film formed on the uneven portion on the surface of the lens has an uneven shape substantially following the shape of the uneven portion on the surface of the lens. As for the uneven portion on the surface of the lens, the average value (P) of the distance between the apexes of the convex portions constituting the uneven shape of the surface of the highly heat-resistant antireflection film is 100 to 400 nm (preferably 150 to 300 nm), or The average value (H) of the heights of the convex portions forming the uneven shape of the surface of the highly heat-resistant antireflection film is 30 to 120 nm (preferably 50 to 100 nm), or further, the H / P is 0.3. It is preferably formed so as to be ~ 1.3.

By setting the H / P to 0.3 to 1.3, it is possible to effectively prevent foreign substances including water droplets from staying in the concave and convex portions on the surface of the highly heat-resistant antireflection film. Further, by setting the average value (mean pitch P) of the distances between the vertices of the convex portions forming the uneven shape of the surface of the highly heat-resistant antireflection film to 400 nm or less, which is smaller than the wavelength of visible light, the entire visible light is covered. It is possible to exhibit good antireflection characteristics and effectively prevent foreign matter including water droplets from staying in the recess. Further, by setting the average pitch P to 100 nm or more, the fluidity of the water droplets described above can be enhanced. Further, in addition to the average pitch P of 100 to 400 nm (or regardless of the average pitch P), by setting the average height H of the convex portion to 50 to 200 nm, the uneven portion on the lens surface and high heat resistant antireflection are prevented. The concavo-convex structure composed of the concavo-convex morphology of the film surface can effectively fulfill the above-mentioned function as the antireflection film.

The smaller the particle size of the particles constituting the high heat resistant antireflection film, the easier it is for the particles to aggregate, and the particles forming the high heat resistant antireflection film aggregate because the agglomerates form irregularities. By making it easier (adjusting the particle size), uneven morphology is likely to be formed on the surface of the high heat resistant antireflection film, but the surface shape of the high heat resistant antireflection film is controlled as in the present invention. If a concavo-convex portion for adjusting the optical performance of the highly heat-resistant antireflection film is provided on the lens surface, a desired concavo-convex shape (desired height and pitch) can be obtained without adjusting the particle size and the like. It can be realized on the surface of a highly heat-resistant antireflection film.

Further, in the above configuration of the present invention, a water-repellent film or a hydrophilic film may be provided on the antireflection film. A water-repellent film or a hydrophilic film is provided by providing a water-repellent film or a hydrophilic film on a highly heat-resistant antireflection film having an excellent antireflection property and having a surface having an uneven shape as described above due to the uneven portion of the lens surface. Water repellency or hydrophilicity can be improved. That is, the water-repellent film or the hydrophilic film provided on the high heat-resistant antireflection film has a shape substantially following the uneven shape of the surface of the high heat-resistant antireflection film, and the surface has an uneven shape. Under certain circumstances, the water droplets adhering to the surface of the concave-convex form are positioned so as to be placed between the convex portions (supported by the top of the convex portion) so as to straddle the concave portions constituting the concave-convex form. As a result, the contact frictional resistance between the membrane and the water droplet is reduced, and the fluidity of the water droplet is increased. At this time, the air layer existing in the recess between the water droplet and the membrane contributes to the promotion of the flow of the water droplet. As a result, for example, when a lens with a film is used as an exposure lens of an in-vehicle camera, water droplets are easily removed from the lens surface by the wind force received during traveling, and visibility through the lens can be improved. Alternatively, in other situations, the water droplets adhering to the surface of the concave-convex form of the water-repellent or hydrophilic film will be located extending between the convex portions so as to enter the concave portions constituting the concave-convex form. As a result, the contact area between the membrane and the water droplet is increased, and the water droplet is susceptible to the water-repellent effect or the hydrophilic effect of the water-repellent membrane or the hydrophilic membrane (the contact area between the water droplet and the water-repellent membrane or the hydrophilic membrane is increased. It can be sufficiently secured to efficiently exert a water-repellent or hydrophilic action on water droplets). As a result, under the water-repellent action, spheroidization of water droplets can be promoted to enhance water repellency and visibility can be improved, and under the hydrophilic action, fine water droplets adhering to the lens surface can be spread over the hydrophilic film. It can be expanded to form a thin water film, which can contribute to anti-fog without staying on the lens surface (it can suppress the formation of dew condensation (fog) on the lens due to a sudden change in temperature and prevent deterioration of visibility). ..

Further, in the above configuration, the water-repellent film or the hydrophilic film formed on the high heat-resistant antireflection film can act as a protective film for the high heat-resistant antireflection film. That is, a highly heat-resistant antireflection film having weak scratch resistance can be protected by a water-repellent film or a hydrophilic film, and the film strength can be increased.

In the above configuration, the lens with a film having a high heat resistant antireflection film may be made of glass or resin. However, as described above, the highly heat-resistant antireflection film has an excellent property of heat resistance that can follow the thermal deformation of the lens, and is therefore particularly suitable for a resin lens that easily expands and contracts due to a temperature change. Further, in the above configuration, a high heat resistant antireflection film may be further provided on the back surface of the lens with or without a hydrophilic film.

Further, in the above configuration, a fluorine-based material (for example, the trade name "WR4" provided by Merck & Co., Inc.) can be used as the water-repellent film. On the other hand, as the hydrophilic film, generally, an acrylic-based (for example, acrylic polymer; "LAMBIC" provided by Osaka Organic Chemical Industry Co., Ltd.) organic hydrophilic film, a silica-based inorganic hydrophilic film, titanium, etc. Photocatalysts such as systems can be mentioned. Further, such a water-repellent film and a hydrophilic film can be formed by, for example, thin-film deposition, coating, spraying, dipping method or the like with or without masking by taping, but it is said that the adhesion strength of the film is enhanced. From the viewpoint, it is preferable to form the water-repellent film and the hydrophilic film by vapor deposition.

Further, in the above configuration, the hydrophilic film is a thin film having hydrophilicity, and the contact angle of water droplets with the hydrophilic film is 40 degrees or less. On the other hand, the water-repellent film is a thin film having water repellency, which means that the contact angle of water droplets with the water-repellent film is 90 degrees or more, and is distinguished from the hydrophilic film in this respect. In this case, the contact angle shall be measured by the intravenous drop method (A, half-angle, Method), and the lens surface on which the film is formed is 2.5 microliters so as not to be affected by the lens surface. Water droplets are dropped, and the curved surface connecting the left and right end points of the droplets is regarded as a straight line, and the contact angle of the water droplets is measured.

Further, in the above configuration, the high heat resistant antireflection film is provided at least within an optically effective range of the lens, including the hydrophilic film and the water repellent film. Therefore, the term "lens surface" in the above configuration may also include a peripheral portion (peripheral end surface) of the lens surface. The high heat resistant antireflection film has a low refractive index, extremely low reflectance, and low dependence of the reflectance on the incident angle. Therefore, if a high heat resistant antireflection film is provided on the periphery of the lens surface, the amount of light around the lens Can contribute significantly to the increase in (and therefore suitable for wide-angle lenses).

Further, in the above configuration of the present invention, the average film thickness of the water-repellent film is 5% to 150% of the average film thickness of the high heat-resistant antireflection film, or the average film thickness of the hydrophilic film is the average film of the high heat-resistant antireflection film. It is preferably 5% to 150% of the thickness. By setting such a film thickness relationship, the film thickness of the water-repellent film or hydrophilic film and the film thickness of the high heat-resistant antireflection film are set to almost the same level, and the water-repellent film or hydrophilic film is made of the high heat-resistant antireflection film. The uneven shape can be well followed, and therefore the surface shape of the water-repellent film or the hydrophilic film can be an effective uneven shape capable of improving the water-repellent performance or the hydrophilic performance.

The present invention also provides a lens unit having the lens with a film and a camera module having the lens unit. With such a lens unit and a camera module, the same effects as those of the above-mentioned lens with a film can be obtained.

According to the lens with a film, the lens unit, and the camera module of the present invention, uneven portions for controlling the surface shape of the high heat resistant antireflection film and adjusting the optical performance of the high heat resistant antireflection film are provided on the surface of the lens. Therefore, the height and pitch of the surface uneven shape of the high heat resistant antireflection film can be optimally adjusted, and the adhesion of the high heat resistant antireflection film can be improved.

It is the schematic sectional drawing of the lens unit which concerns on one Embodiment of this invention. It is the schematic sectional drawing of the camera module including the lens unit of FIG. FIG. 5 is an enlarged cross-sectional view of a main part conceptually showing the structure of a highly heat-resistant antireflection film formed on the lens surface constituting the lens unit of FIG. 1. It is an enlarged cross-sectional view of a main part which conceptually and stepwise shows the structure of another highly heat-resistant antireflection film made of a fine particle laminated thin film having voids. 3 is a cross-sectional view of a main part conceptually showing the surface shape of the highly heat-resistant antireflection film having the structural form shown in FIG. 3 or 4, and FIG. 3A is a cross-sectional view when there is no uneven portion on the surface of the lens. (B) is a cross-sectional view when there is an uneven portion on the surface of the lens. It is an enlarged sectional view of the part A of FIG. 5 (b). It is an enlarged cross-sectional view of a main part conceptually showing the laminated structure of the highly heat-resistant antireflection film and the water-repellent film or the hydrophilic film provided on the lens surface having an uneven part. (A) is an enlarged cross-sectional view of a main part conceptually showing a state in which water droplets are attached between the convex portions so as to straddle the concave portions forming the concave-convex shape of the surface of the water-repellent film or the hydrophilic film, and (b) is an enlarged sectional view of a main part. It is an enlarged cross-sectional view of a main part conceptually showing a state in which water droplets extend and are positioned between the convex portions so as to enter the concave portions constituting the shape. It is a figure which shows various forms of the concavo-convex portion having a convex portion protruding from the surface of a lens. It is a figure which shows various forms of the concavo-convex portion having a groove-like recess which is bored from the surface of a lens. It is a top view which shows an example of the arrangement form of the concave part shown in FIG. 10 on the surface of a lens. It is a top view which shows an example of the arrangement form of the convex part shown in FIG. 9 on the surface of a lens.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The lens unit of the present embodiment described below is particularly for a camera module such as an in-vehicle camera. For example, the lens unit is fixedly installed on the outer surface side of an automobile, and wiring is drawn into the automobile. Is connected to a display or other device. Note that hatching is omitted for a plurality of lenses in FIGS. 1 and 2 described below.

FIG. 1 shows a lens unit 11 according to an embodiment of the present invention. As shown in the figure, the lens unit 11 of the present embodiment is, for example, a resin or metal cylindrical lens barrel (barrel) 12 and glass arranged in the stepped inner accommodation space S of the lens barrel 12. A plurality of lenses made of or made of resin, for example, five lenses including a first lens 13, a second lens 14, a third lens 15, a fourth lens 16 and a fifth lens 17, and an aperture (not shown). It is equipped with a member. The diaphragm member is an "aperture diaphragm" that limits the amount of transmitted light and determines an F value that is an index of brightness, or a "light-shielding diaphragm" that blocks light rays that cause ghosts and light rays that cause aberrations. An in-vehicle camera including such a lens unit 11 includes a lens unit 11, a substrate having an image sensor (not shown), and an installation member (not shown) for installing the substrate in a vehicle such as an automobile.

The plurality of lenses 13, 14, 15, 16, and 17 fixed and supported by the lens barrel 12 are arranged in a state where their respective optical axes are aligned with each other, and each lens is arranged along one optical axis O. 13, 14, 15, 16 and 17 are arranged side by side to form a group of lens groups L used for imaging. Of these, the two fourth and fifth lenses 16 and 17 located on the image side (the innermost innermost side of the inner accommodation space S) may be, for example, bonded lenses.

An object-side end (upper end in FIG. 1) of the lens barrel 12 is provided with a caulking portion 23 for caulking the end in the radial direction, and the caulking portion 23 is the most object of the lens group L. The first lens 13 located on the side is fixed to the end of the lens barrel 12 on the object side.

Further, an inner flange portion 24 having an opening having a diameter smaller than that of the fifth lens 17 is provided at the image-side end portion (lower end portion in FIG. 1) of the lens barrel 12. The inner flange portion 24 and the caulking portion 23 hold a plurality of lenses 13, 14, 15, 16, 17 and an aperture member forming the lens group L in the lens barrel 12.

On the outer peripheral surface of the first lens 13 located closest to the object, a reduced diameter portion having a smaller diameter is provided on the image side portion of the lens 13, and the reduced diameter portion is an O-ring 26 as a sealing member. Is provided, and the outer peripheral surface of the lens 13 and the inner peripheral surface of the lens barrel 12 are sealed by the object-side end of the lens barrel 12. This prevents fine particles such as water and dust from entering the lens barrel 12 from the end of the lens unit 11 on the object side.

The inner and outer diameters of the lens barrel 12 are gradually reduced from the object side to the image plane side. That is, the lens barrel 12 has a large-diameter portion 12A for accommodating and holding the first and second lenses 13 and 14, and a small-diameter portion 12B for accommodating and holding the third to fifth lenses 15, 16 and 17. Further, corresponding to the stepped shape of the lens barrel 12, the outer diameters of the lenses 13, 14, 15, 16 and 17 become smaller from the object side to the image plane side. Basically, the outer diameters of the lenses 13, 14, 15, 16 and 17 and the inner diameters of the portions of the lens barrel 12 where the lenses 13, 14, 15, 16 and 17 are supported (held) are It is almost equal. On the outer peripheral surface of the lens barrel 12, an outer flange portion 25 used when the lens barrel 12 is installed on the in-vehicle camera is provided on the outer peripheral surface of the lens barrel 12 in a flange shape.

Further, in the present embodiment, the first lens 13 located on the most object side of the lens group L has an outer surface (“lens surface”) on each of the object side and the image side. That is, the first lens 13 has a lens surface 13a facing the object side and a lens back surface 13b facing the image side. Further, the first lens 13 is formed of resin in the present embodiment, and is a lens with a film having an antireflection film 30 formed at least on the lens surface 13a. In the following, the film formation form of the first lens 13 as a lens with a film will be described, but the other lenses 14, 15, 16 and 17 constituting the lens group L have the same or similar film formation form. It may be formed as a lens with a film.

Further, in the present embodiment, the antireflection film 30 formed on the lens surface 13a of the first lens 13 is provided as a highly heat-resistant antireflection film, which will be described in more detail below. Further, in the present embodiment, the high heat resistant antireflection film 30 is also provided on the lens back surface 13b of the first lens 13. Then, in the present embodiment, the water-repellent film 50A is further formed on the high heat-resistant antireflection film 30 provided on the lens surface 13a. However, in another embodiment, the hydrophilic film 50B (shown in parentheses in FIG. 1) is on the highly heat resistant antireflection film 30 provided on the lens surface 13a of the first lens 13, which may or may not be exposed to the outside. The hydrophilic film 50B may be formed on the highly heat-resistant antireflection film 30 provided on the lens back surface 13b of the first lens 13. Further, the high heat resistant antireflection film 30 may not be provided on the back surface 13b of the first lens 13. Further, a high heat resistant antireflection film 30 is provided on the lens front surface and / or the lens back surface of the other lenses 14, 15, 16 and 17 constituting the lens group L, and a hydrophilic film 50B is provided on the heat resistant antireflection film 30. May be done. In this embodiment, it is assumed that the highly heat-resistant antireflection film 30 is directly formed on the lens surface 13a of the first lens 13.

Further, FIG. 2 shows a schematic cross-sectional view of the camera module 300 of the present embodiment having the lens unit 11 having the above configuration. As shown in the figure, the camera module 300 includes the lens unit 11 of FIG. 1 to which the filter 100 is mounted.

The camera module 300 includes an upper case (camera case) 301, which is an exterior component, and a mount (pedestal) 302 that holds the lens unit 11. Further, the camera module 300 includes a seal member 303 and a package sensor (image sensor) 304.

The upper case 301 is a member that exposes the end portion of the lens unit 11 on the object side and covers the other portion. The mount 302 is arranged inside the upper case 301 and has a female screw 302a that is screwed with the male screw 11a of the lens unit 11. The seal member 303 is a member inserted between the inner surface of the upper case 301 and the outer peripheral surface 12a of the lens barrel 12 of the lens unit 11, and is a member for maintaining the airtightness inside the upper case 301. ..

The package sensor 304 is arranged inside the mount 302 and is arranged at a position where it receives an image of an object formed by the lens unit 11. Further, the package sensor 304 includes a CCD, CMOS, and the like, and converts the light that is focused and reaches through the lens unit 11 into an electric signal. The converted electrical signal is converted into analog data or digital data, which are components of image data captured by the camera.

The high heat resistant antireflection film 30 formed on the lens surface 13a and the lens back surface 13b of the first lens 13 is adjacent to a plurality of inorganic particles having a volume ratio of 5 to 74% in the high heat resistant antireflection film 30. A plurality of air layers having a volume ratio of 65% or less (not including 0% volume ratio, and the air layer is an essential component of the high heat resistant antireflection film 30) formed between the matching inorganic particles. An organic compound, an inorganic compound, or an inorganic polymer that binds the inorganic particles or the inorganic particles and the air layer, has a younger ratio than the inorganic particles, and has a volume ratio of 5 to 95%. Is equipped with. This will be described in detail below.

FIG. 3 is an enlarged cross-sectional view of a main part of the lens 13 (or 14-17) formed with the highly heat-resistant antireflection film 30 in the vicinity of the light incident surface. As shown in the figure, the high heat resistant antireflection film 30 includes a plurality of inorganic particles 31, a binder 32, and a plurality of air layers (voids) 33. The viscoelasticity of the inorganic particles 31 is different from the viscoelasticity of the binder 32. Specifically, the Young's modulus of the inorganic particles 31 is 50 GPa or more. The Young's modulus of the binder 32 is 5 GPa or less.

The high heat resistant antireflection film 30 contains a plurality of compositions having different viscoelasticities. Therefore, the high heat resistant antireflection film 30 has high strength and high flexibility. The lens 13 (or 14-17) made of resin expands due to heat. Since the Young's modulus of the binder 32 is low, the flexibility of the highly heat-resistant antireflection film 30 is high. Therefore, even if the lens 13 (or 14-17) expands due to heat, the highly heat-resistant antireflection film 30 is not easily cracked. On the other hand, the Young's modulus of the inorganic particles 31 is 50 GPa or more. The inorganic particles 31 improve the strength of the high heat resistant antireflection film 30 and suppress the formation of scratches on the surface of the high heat resistant antireflection film 30.

The binder 32 has light transmission and contains a plurality of inorganic particles 31. As described above, the Young's modulus of the binder 32 is 5 GPa or less. The binder 32 is an organic compound or an inorganic compound. The binder 32 is, for example, a resin. The resin is, for example, polyethyleneimine, polyallylamine, polyvinylamine, polyvinylpyridine, diallylamine polymer, maleic acid-diallylamine copolymer, polyvinyl alcohol, polyoxyethylene, polymethylmethacrylate, polymethylacrylate, diacetylcellulose, triacetylcellulose. , Nitrocellulose, polyester, alkyd resin, fluoroacrylate, fluoropolymer and the like, or more. Fluoropolymers include, for example, fluoroolefins (fluoroethylene, vinylidene fluoride, tetrafluoroethylene, perfluorooctylethylene, hexafluoropropylene, perfluoro-2, 2-dimethyl-1,3-dioxol, etc.), complete or partial. Fluorinated vinyl ethers and the like. The refractive index of the binder 32 is 1.35 or less, and the preferable refractive index is 1.30 or less.

Further, the binder 32 may be an inorganic polymer, for example, a silicon compound, a hydrolyzate thereof, or a polycondensate product thereof. The silicon compound is, for example, a silane coupling agent. The silane coupling agent modifies the surface of the inorganic particles. As a result, the dispersion stability of the inorganic particles in the organic solvent is improved, and the aggregation and sedimentation of the inorganic particles are suppressed.

The inorganic particles 31 are, for example, inorganic oxides and inorganic fluorides. Inorganic oxides are, for example, cerium oxide, tantalum oxide, titanium oxide, silicon oxide, chromium oxide, aluminum oxide, tin oxide, yttrium oxide, and bismuth oxide. Inorganic fluorides are, for example, magnesium fluoride, aluminum fluoride, lithium fluoride, sodium fluoride. The plurality of inorganic particles 31 include one or more selected from the above-mentioned inorganic oxides and inorganic fluorides.

Preferably, the inorganic particles 31 are aluminum oxide and / or silicon oxide. The refractive indexes of aluminum oxide and silicon oxide are both low. The refractive index of aluminum oxide is 1.7 to 1.9, and the refractive index of silicon oxide is 1.4 to 1.7. Therefore, the refractive index of the highly heat-resistant antireflection film 30 can be lowered.

If the particle size of the inorganic particles 31 is too large, the inorganic particles 31 tend to scatter light. Further, the film thickness of the high heat resistant antireflection film 30 varies. Therefore, the preferable average particle size of the inorganic particles 31 is 100 nm or less. The preferable lower limit of the average particle size is 8 nm. The particle size is determined, for example, by measuring the particle size of 100 inorganic particles arbitrarily extracted from a photographic image by a scanning electron microscope (SEM) and obtaining an average value thereof.

The volume fraction of the inorganic particles 31 in the high heat resistant antireflection film 30 is 5 to 74%. The volume fraction of the binder 32 in the high heat resistant antireflection film 30 is 5 to 95%. The volume fraction of the air layer in the high heat resistant antireflection film 30 is 65% or less.

If the volume fraction of the inorganic particles 31 is too small, the strength of the high heat resistant antireflection film 30 decreases. Further, if the volume fraction of the inorganic particles 31 is too large, the flexibility of the high heat resistant antireflection film 30 decreases. On the other hand, if the volume fraction of the binder 32 is too small, the flexibility of the high heat resistant antireflection film 30 decreases. Further, if the volume fraction of the binder 32 is too large, the strength of the high heat resistant antireflection film 30 decreases.

If the volume fraction of the inorganic particles 31 is 5 to 74%, the volume fraction of the binder 32 is 5 to 95%, and the air layer is 65% or less, the high heat resistant antireflection film 30 is flexible and Has strength. Therefore, the high heat resistant antireflection film 30 is not easily scratched, and even if the lens made of resin is thermally expanded at a high temperature, the high heat resistant antireflection film 30 is not easily cracked.

The high heat resistant antireflection film 30 is formed by a wet process. More specifically, the high heat resistant antireflection film 30 is formed by applying the coating liquid constituting the high heat resistant antireflection film 30 to the surface of the lens 13 (or 14-17 as well). The method of applying the coating liquid is, for example, an inkjet printing method, a spray method, a spin coating method, a dip coating method, screen printing, or the like.

Hereinafter, as an example of the manufacturing method, a method of forming an antireflection film by a dip coating method will be described.
A coating liquid containing the composition of the highly heat-resistant antireflection film 30 is prepared. The solvent used in the coating solution is, for example, tetrahydrofuran (THF) or N, N-dimethylformamide (DMF). The solvent is not limited to these substances. The solvent may be water. When the solvent is an organic solvent, the boiling point of the organic solvent is preferably 30 ° C. to 250 ° C. If the boiling point of the organic solvent is too low, the volatilization rate of the organic solvent is too fast. Therefore, it is difficult for the film thickness of the high heat resistant antireflection film 30 to become uniform. On the other hand, if the boiling point of the organic solvent is too high, the organic solvent is unlikely to volatilize. Therefore, it is difficult to form the highly heat-resistant antireflection film 30. The boiling point of the preferred organic solvent is 50 ° C to 150 ° C.
The viscosity and surface tension of the coating liquid are preferably low. The viscosity of the coating liquid is preferably 10 (mPa · s) or less, more preferably 1 (mPa · s) or less. The preferable surface tension of the coating liquid is 70 (mN / m) or less, and more preferably 20 (mN / m) or less. This is because when the holding member holding the lens 13 (or 14-17) is pulled up from the dip tank filled with the coating liquid, the coating liquid is quickly discharged from the holding member. A surfactant or the like may be added to the coating liquid in order to control the physical properties of the viscosity and surface tension of the coating liquid.

In the coating liquid, the weight part of the binder 32 is 1 to 100 with respect to 100 parts by weight of the inorganic particles 31, and the weight part of the solvent is 2000 to 100,000. In this case, the volume fraction of the inorganic particles 31 in the formed high heat resistant antireflection film 30 is 5 to 70%, and the volume fraction of the binder 32 is 30 to 95%.

Next, the lens 13 (or 14-17) is sandwiched between the sandwiching members and immersed in a dip tank containing the coating liquid.

Next, the immersed lens 13 (or 14-17) is pulled up from the dip tank at a constant speed. As a result, the coating liquid is applied to the surface of the lens 13 (or 14-17 as well). The speed of pulling up is changed according to the thickness of the highly heat-resistant antireflection film 30 formed on the surface of the lens 13 (or 14-17).

Next, the coating liquid applied to the lens 13 (or 14-17) is dried. The pulled lens 13 (or 14-17) may be baked at a predetermined temperature.
As a result, the highly heat-resistant antireflection film 30 is formed.

Inorganic particles 31 come into contact with each other in the highly heat-resistant antireflection film 30. An air layer 33 is formed between adjacent inorganic particles 31. As described above, the volume fraction of the inorganic particles 31 in the highly heat-resistant antireflection film 30 is 5 to 74%, and may be less than 70%. The volume fraction of the binder 32 is 5 to 95%, and may be less than 95%. If the volume fraction of the air layer 33 is too large, the strength of the high heat resistant antireflection film 30 decreases. Therefore, the volume fraction of the air layer 33 in the high heat resistant antireflection film 30A is 65% or less.

The air layer 33 is formed, for example, according to the ratio of the binder 32 to the above-mentioned inorganic particles 31 in the coating liquid. The preferred weight portion of the binder 32 with respect to 100 parts by weight of the inorganic particles in the coating liquid is 1 to 100. In this case, after the coating liquid is dried, the air layer 33 is formed in the highly heat-resistant antireflection film 30A.

Since the air layer 33 has a low refractive index, the refractive index of the highly heat-resistant antireflection film 30 decreases. Therefore, the reflection of light is further suppressed.
With such a configuration, the high heat resistant antireflection film 30 has flexibility and flexibility and is excellent in heat resistance, and as a result, cracks and the like of the high heat resistant antireflection film at high temperature can be prevented. In this case, in particular, since the air layer (void) 33 is formed between the adjacent inorganic particles 31 and 31, the lens 13 (or 14-17) on which the highly heat-resistant antireflection film 30 is formed is formed. Even if it expands or contracts due to a temperature change, the highly heat-resistant antireflection film 30 can follow it. Therefore, it is possible to prevent the highly heat-resistant antireflection film 30 from being destroyed.

FIG. 4 shows the high heat resistant antireflection film 30 shown in FIG. 3 in more detail from a different point of view, and is basically the same as the high heat resistant antireflection film 30 shown in FIG. However, in the following description, the structure and film forming method of the high heat resistant antireflection film shown in FIG. 4 will be described as the high heat resistant antireflection film 30A. The highly heat-resistant antireflection film 30A is made of a fine particle laminated thin film having voids, and in this fine particle laminated thin film, an electrolyte polymer (binder) and fine particles are alternately adsorbed, and the alcoholic silica sol product is brought into contact with the lens to bring the lens and fine particles into contact with each other. And the fine particles are bonded to each other.

Such a fine particle laminated thin film (high heat resistant antireflection film) 30A is formed as follows. As shown in FIG. 4, a fine particle laminated thin film 30A having a void 64 is formed on the lens 13 (or 14-17 as well). The fine particle laminated thin film 30A alternately adsorbs the electrolyte polymer 62 (for example, binder) and the fine particles 63, and the lens 13 (or 14-17 also) and the fine particles are passed through the alcoholic silica sol product 65 (for example, binder). 63 and the fine particles 63 and the fine particles 63 are configured to be bonded. Hereinafter, each component of the fine particle laminated thin film 30A will be described.

The fine particles used for forming the fine particle laminated thin film 30A preferably have an average primary particle diameter of 2 to 100 nm in a state of being dispersed in the solution in order to obtain the transparency of the fine particle laminated thin film 30A. From the viewpoint of ensuring the optical function, 2 to 40 nm is more preferable, and 2 to 20 nm is most preferable.

Examples of the fine particles that can be used here include inorganic fine particles. Preferably, an oxide containing at least one element selected from the group consisting of silicon, aluminum, zirconium, titanium, niobium, zinc, tin, cerium and magnesium is preferably selected from the viewpoint of transparency.

As the electrolyte polymer used here, a polymer having a charged functional group in the main chain or the side chain can be used. This electrolyte polymer solution is obtained by dissolving an electrolyte polymer having a charge opposite to or the same as the surface charge of the fine particles in water, an organic solvent, or a mixed solvent of a water-soluble organic solvent and water.

As the alcohol-based silica sol, 4, 3, and bifunctional alkoxysilanes, condensates, hydrolysates, and silicone varnishes of these alkoxysilanes can be used. The alcoholic silica sol product preferably contains an alcoholic silica sol prepared by hydrolyzing at least one lower alkyl silicate represented by the following general formula in either methanol or ethanol. ..
(OR ¹ ) nSi (R ² ) _4-n (n = 1 to 4) ... (1)
(In the formula, R ¹ represents a methyl group or an ethyl group. R ² represents a non-hydrolyzable organic group.)

Further, the lens 13 (or 14-17) is used as it is, or the surface thereof is subjected to corona discharge treatment, glow discharge treatment, plasma treatment, ultraviolet irradiation, ozone treatment, chemical etching treatment with alkali, acid or the like. A polar functional group is introduced by a silane coupling treatment or the like to negatively or positively charge the surface charge of the lens.

Here, in order to generate the fine particle laminated thin film 30A having voids, for example, a dip coating method is used. The fine particle laminated thin film 30A can be formed by sequentially performing the following steps (1) to (3) (see FIG. 4).
(1) A layer of the electrolyte polymer 62 or the fine particles 63 is formed by contacting or applying either the electrolyte polymer solution or the fine particle dispersion liquid onto the lens 13 (or 14-17) (FIG. 4 (a)). )).
(2) A step of contacting or applying a dispersion of fine particles having an opposite charge to the electrolyte polymer of the electrolyte polymer solution on the lens 13 (or 14-17) after the contact or application of the electrolyte polymer solution, or A layer of the fine particles 63 or the electrolyte polymer 62 is formed by a step of contacting or applying a solution of an electrolyte polymer having an opposite charge to the fine particles of the fine particle dispersion on a plastic substrate after the fine particle dispersion is contacted or applied. (Fig. 4 (b)).
(3) The alcoholic silica sol product 65 is provided by the step of contacting or coating the alcoholic silica sol product 65 on the lens 13 (or 14-17) after the electrolyte polymer solution or the fine particles are contacted or coated. The lens 13 (or 14-17 is also used), the fine particles 63, and the fine particles 63 are coupled to each other via the medium (FIG. 4 (c)).
With such a configuration, the high heat resistant antireflection film 30A has flexibility and flexibility and is excellent in heat resistance, and as a result, cracks and the like of the high heat resistant antireflection film at high temperature can be prevented. In this case, in particular, even if the lens 13 (or 14-17) on which the high heat resistant antireflection film 30A is formed expands or contracts due to a temperature change due to the presence of the void 64, the high heat resistant antireflection film is prevented. The film 30A can follow it. Therefore, it is possible to prevent the high heat resistant antireflection film 30A from being destroyed.
The high heat resistant antireflection films 30 and 30A as described above have a heat resistance of 125 ° C. or higher and a thermal expansion coefficient close to the thermal expansion coefficient of the resin lens 13 (or 14-17). It is preferable to select.

Further, in the step of forming the fine particle laminated thin film (high heat resistant antireflection film) 30A shown in FIG. 4, the alcoholic silica sol product 65 was used in order to improve the fixability of the film, but of course, the alcoholic silica sol product The highly heat-resistant antireflection film 30A can be formed without using 65. In that case, for example, a silica aqueous dispersion in which beaded silica fine particles having an average primary particle size of 8 nm measured by the BET method are dispersed (manufactured by Nissan Chemical Industries, Ltd., trade name: Snowtex (ST) OUP, Silica sol) was used as a fine particle dispersion with a negative charge whose concentration was adjusted to 1% by mass without adjusting the pH, and polydiallyldimethylammonium chloride (PDDA, manufactured by Aldrich) was adjusted to 0.1% by mass and pH 10. The aqueous solution is used as an electrolyte polymer solution. Then, after immersing each of the lenses 13 (or 14-17) in the electrolyte polymer solution for 1 minute, the step (a) of showering the ultrapure water for rinsing for 1 minute, and after immersing in the fine particle dispersion for 1 minute. The step (b) of showering ultrapure water for rinsing for 1 minute is performed in this order. After that, one cycle of step (a) and one step (b) are taken as one cycle, the number of cycles is defined as the number of alternating fine particle laminations, the number of alternating fine particle laminations is four times, and then 24 hours at 25 ° C. dry. As a result, the fine particle laminated film 30A is formed on the surface of the lens 13 (or 14-17). That is, in this production method, the first step of contacting the surface of the lens 13 (or 14-17) with the electrolyte polymer solution (binder solution) and then rinsing, and after this first step, the lens 13 (or 14-17) The second step of contacting the surface of (14-17) with a dispersion of fine particles having a negative charge and then rinsing, and the first step and the second step are alternately repeated to form a fine particle laminated film. A third step of forming is included, and optionally, a further step of contacting the fine particle laminate with the electrolyte polymer solution (binder solution) and then rinsing is included, whereby the step of FIG. 4 (c) Be excluded.

By forming the antireflection film 30 (or 30A) in the above-described form, the surface of the highly heat-resistant antireflection film 30 inevitably has an uneven shape as shown in FIG. 5A. However, in the present embodiment, as shown in FIG. 5B, the optical performance of the high heat resistant antireflection film 30 is controlled by controlling such a surface uneven shape of the high heat resistant antireflection film 30. The uneven portion 80 for adjusting the lens 13 (14-17) is provided on the surface of the lens 13 (14-17). Note that the uneven portion 80 is not shown in FIGS. 3 and 4 for convenience.

Such an uneven portion 80 provided on the surface of the lens 13 (14-17) can affect the uneven form C1 on the surface of the highly heat-resistant antireflection film 30 as shown in FIG. 5 (b). Specifically, for example, the uneven shape C1 on the surface of the high heat resistant antireflection film 30 can be made into a shape corresponding to the shape of the uneven portion 80 on the surface of the lens 13 (14-17), and the high heat resistant antireflection film 30 can be formed. The height H and the pitch P of the uneven shape C1 on the surface of the surface 30 can be optimally adjusted by the uneven portion 80.

The uneven portion 80 on the surface of the lens 13 (14-17) enables the height H and the pitch P of the uneven form C1 of the high heat resistant antireflection film 30 to be adjusted, whereby the optics of the high heat resistant antireflection film 30 can be adjusted. It is for adjusting the performance. In other words, the uneven portion 80 is for realizing desired antireflection characteristics in cooperation with the high heat resistant antireflection film 30, and does not itself have an optical function. Therefore, for example, the height (depth) X (see (b) of FIG. 5) of the uneven portion 80 is set to 70 nm so that the concave-convex portion 80 itself does not have an optical function. However, the uneven portion 80 may have an optical function by itself.

The uneven portion 80 on the surface of the lens 13 (14-17) may be formed on the lens 13 (14-17), for example, when the lens 13 (14-17) is made of resin as in the present embodiment. It may be formed by processing unevenness on the mold for forming the lens 13 (14-17), or if the lens 13 (14-17) is made of glass, it is formed on the surface of the lens 13 (14-17) by etching or the like. May be done.

The uneven shape C1 of such a surface of the highly heat-resistant antireflection film 30 formed (adjusted) due to the uneven portion 80 reflects light even when the incident angle of light fluctuates, as compared with a smooth surface. (Achieves an antireflection film with low incident angle dependence). That is, as shown in FIG. 6, which is an enlarged view of part A in FIG. 5B, the light 70 incident on the highly heat-resistant antireflection film 30 is the unevenness of the convex portion 30a and the concave portion 30b constituting the concave-convex form C1. While repeating reflection in the plane, it is taken into the high heat resistant antireflection film 30 and the reflection to the outside of the high heat resistant antireflection film 30 is suppressed. Further, in such a high heat resistant antireflection film 30, the film thickness determined by the desired refractive index is set to 1 of the wavelength λ of the visible light so that the phase of the reflected light and the phase of the incident light overlap each other and cancel each other out. By setting it to a multiple of / 4 (for example, 100 nm), excellent antireflection characteristics can be realized.

That is, the highly heat-resistant antireflection film 30 having the above configuration has an antireflection effect due to the uptake of light accompanying the concave-convex form C1 and an antireflection effect due to setting the film thickness to a multiple of 1/4 of the wavelength λ of visible light. Due to the synergistic effect with, it has excellent antireflection characteristics (high light transmittance) as compared with the conventional antireflection film. In combination with this synergistic effect, the highly heat-resistant antireflection film 30 is formed in the form of the composition of the above-mentioned inorganic particles, air layer and compound, or the form of a fine particle laminated thin film, thereby providing flexibility and flexibility. It has flexibility and excellent heat resistance, and as a result, it is possible to prevent cracks in the highly heat-resistant antireflection film at high temperatures. In this case, in particular, since the air layers (voids) 33 and 64 are formed between adjacent inorganic particles, the lens on which the highly heat-resistant antireflection film 30 is formed may expand or contract due to a temperature change. Even so, the highly heat-resistant antireflection film 30 can follow suit. Therefore, it is possible to prevent the highly heat-resistant antireflection film 30 from being destroyed.

Then, in the present embodiment, a water-repellent film 50A or a hydrophilic film 50B is further formed on the highly heat-resistant antireflection film 30 having a surface forming such an uneven form C1 and having excellent antireflection characteristics ( For example, by providing it at 100 nm), the water-repellent performance or the hydrophilic performance of the water-repellent film 50A or the hydrophilic film 50B can be improved. That is, the water-repellent film 50A or the hydrophilic film 50B provided on the high heat-resistant antireflection film 30 has a shape substantially following the uneven shape C1 on the surface of the high heat-resistant antireflection film 30 as shown in FIG. The surface of the ridge has a concave-convex form C2 having a convex portion 50a and a concave portion 50b. Therefore, in a certain situation, the water droplet 90 adhering to the surface of the concave-convex form C2 is shown in FIG. As a result, the film 50A (supported by the top T of the convex portion 50a) is placed between the convex portions 50a so as to straddle the concave portion 50b forming the concave-convex shape. The contact frictional resistance between 50B) and the water droplet 90 is reduced, and the fluidity of the water droplet 90 is increased. At this time, the air layer 85 existing in the recess 50b between the water droplet 90 and the membrane 50A (50B) contributes to promoting the flow of the water droplet 90. As a result, for example, when the lens 13 with a film is used as the exposure lens (first lens) of the in-vehicle camera, the water droplet 90 is easily removed from the lens surface by the wind force received during traveling, and the water droplet 90 is easily removed from the lens surface and passed through the lens 13. Visibility can be improved. Alternatively, in another situation, as shown in FIG. 8B, the water droplet 90 adhering to the surface of the concave-convex form C2 of the water-repellent film 50A or the hydrophilic film 50B enters the concave portion 50b constituting the concave-convex form. As a result, the contact area between the film 50A (50B) and the water droplet 90 is increased, and the water droplet 90 is the water-repellent film 50A or the hydrophilic film. It becomes easy to receive the water-repellent effect or the hydrophilic effect of 50B (the contact area between the water droplet 90 and the water-repellent film 50A or the hydrophilic film 50B is sufficiently secured, and the water-repellent or hydrophilic action is efficiently applied to the water droplet 90. Can affect). As a result, under the water-repellent action, the spheroidization of the water droplet 90 can be promoted to enhance the water repellency and the visibility can be improved, and under the hydrophilic action, the fine water droplet 90 adhering to the lens surface can be formed on the hydrophilic film. It spreads over the top to form a thin water film that can contribute to anti-fog without staying on the lens surface (suppresses condensation (fog) on the lens due to sudden changes in temperature and prevents deterioration of visibility. it can).

In the present embodiment, a fluorine-based material (for example, trade name "WR4" provided by Merck & Co., Inc.) can be used as the water-repellent film 50A. On the other hand, the hydrophilic film 50B generally includes an acrylic-based hydrophilic film (for example, acrylic polymer; "LAMBIC" provided by Osaka Organic Chemical Industry Co., Ltd.), an inorganic-based hydrophilic film such as silica-based, and the like. Examples thereof include titanium-based photocatalysts. Further, such a water-repellent film 50A and a hydrophilic film 50B can be formed by, for example, vapor deposition, coating, spraying, dipping method or the like with or without masking by taping, but the adhesion strength of the film is increased. From the viewpoint of enhancing, it is preferable to form the water-repellent film 50A and the hydrophilic film 50B by vapor deposition. On the other hand, the highly heat-resistant antireflection film 30 that is the base of these films 50A (50B), including the hydrophilic film 50A and the water-repellent film 50B, is within at least an optically effective range of the lens 13 (14-17). It is provided.

Further, in the present embodiment, the uneven portion 80 on the surface of the lens 13 (14-17) which is the base of the high heat resistant antireflection film 30 and the water repellent film 50A or the hydrophilic film 50B is the surface of the high heat resistant antireflection film 30. The average value of the distance between the apexes (arrangement pitch of the convex portions 30a) P (see FIGS. 6 and 7) between the convex portions 30a and 30a constituting the concave-convex shape is 100 to 400 nm (preferably 150 to 300 nm). Or so that the average value of the height H (see FIGS. 6 and 7) of the convex portion 30a is 30 to 120 nm (preferably 50 to 100 nm), or further, the H / P is 0.3 to 0.3 to The shape, arrangement form, various dimensions (width, height X, etc.) and the like are set so as to be 1.3. Further, such dimensional setting of pitch P and height H also applies to the uneven form C2 on the surface of the water-repellent film 50A and the hydrophilic film 50B formed on the high heat-resistant antireflection film 30. In particular, in the present embodiment, the average film thickness of the water-repellent film 50A is set to 5% to 150% of the average film thickness of the high heat-resistant antireflection film 30, and the average film thickness of the hydrophilic film 50B is high heat-resistant reflection. It is set to 5% to 150% of the average film thickness of the prevention film 30. By setting such a film thickness relationship, the film thickness of the water-repellent film 50A or the hydrophilic film 50B and the film thickness of the high heat-resistant antireflection film 30 are made substantially the same level, and the water-repellent film 50A or the hydrophilic film 50B is made high. The surface shape of the water-repellent film 50A or the hydrophilic film 50B should be an effective uneven shape capable of improving the water-repellent performance or the hydrophilic performance, so that the uneven shape of the heat-resistant antireflection film 30 can be followed well. Can be done.

9 to 12 show an example of an arrangement and formation form of the uneven portion 80 that can enable such dimension setting of the pitch P and the height H.
The concave-convex portion 80 shown in FIGS. 9A to 9D has convex portions 80A, 80B, 80C, 80D protruding from the surface of the lens 13 (14-17). In this case, the concave portion of the uneven portion 80 is formed by the surface of the lens 13 (14-17). Specifically, the convex portion 80A shown in FIG. 9A is formed as a cylinder or a quadrangular prism, and the convex portion 80B shown in FIG. 9B is formed in a cannonball shape, and the convex portion 80B shown in FIG. The convex portion 80C shown in) is formed in a conical shape. Further, the convex portion 80D shown in FIG. 9D is formed in a prismatic shape having a square upper end surface 80Da, a square lower end surface 80Db, and a tapered side surface 80Dc tapering toward the upper end. ..

On the other hand, the uneven portion 80 shown in FIGS. 10A to 10D has groove-shaped recesses 80E, 80F, 80G, 80H formed from the surface of the lens 13 (14-17). .. In this case, the convex portion of the concave-convex portion 80 is formed by the surface of the lens 13 (14-17). Specifically, the recess 80E shown in FIG. 10A has a flat lower end surface 80Eb and an inclined surface 80Ea extending from the surface of the lens 13 (14-17) to the lower end surface 80Eb. It tapers toward the lower end surface 80Eb. Further, the recess 80F shown in FIG. 10B has a lower end edge 80Fb extending linearly and an inclined surface 80Fa extending from the surface of the lens 13 (14-17) to the lower end edge 80Fb, and the lower end edge 80F. It is formed as a V-shaped groove that tapers toward 80 Fb. Further, the recess 80G shown in FIG. 10 (c) is formed as a recessed groove having a parabolic cross section. Further, the recess 80H shown in FIG. 10D has a flat lower end surface 80Hb and a side surface 80Ea extending vertically from the surface of the lens 13 (14-17) to the lower end surface 80Eb.

FIG. 11 shows an example of the arrangement form of the recesses 80E, 80F, 80G, 80H shown in FIG. 10 on the surface of the lens 13 (14-17) in a plan view. In FIG. 11A, the recesses 80E, 80F, 80G, and 80H extend along the line L1 extending in a grid pattern. In this case, all of these lines L1 may be formed by only one of the recesses 80E, 80F, 80G, 80H, or two or more of the recesses 80E, 80F, 80G, 80H. Depending on the combination, these grid-like lines L1 may be formed. Further, in FIG. 11B, recesses 80E, 80F, 80G, and 80H extend along a plurality of concentric circles Ca. In this case as well, all of these concentric circles Ca may be formed by only one of the recesses 80E, 80F, 80G, 80H, or among the recesses 80E, 80F, 80G, 80H. These concentric circles Ca may be formed by a combination of two or more of. Further, in FIG. 11 (c), the recesses 80E, 80F, 80G, 80H extend along the line L2 extending radially. Also in this case, all of these lines L2 may be formed by only one of the recesses 80E, 80F, 80G, 80H, or two or more of the recesses 80E, 80F, 80G, 80H. These radial lines L2 may be formed by the combination of.

FIG. 12 is a plan view showing an example of the arrangement of the convex portions 80A, 80B, 80C, and 80D shown in FIG. 9 on the surface of the lens 13 (14-17). In FIG. 12A, the convex portions 80A, 80B, 80C, and 80D are provided at predetermined intervals along the line L1 extending in a grid pattern. In this case, all of these lines L1 may be formed by only one of the convex portions 80A, 80B, 80C, 80D, or two of the convex portions 80A, 80B, 80C, 80D. These grid-like lines L1 may be formed by the above combination. Further, in FIG. 12B, convex portions 80A, 80B, 80C, and 80D are provided along a plurality of concentric circles Ca at predetermined intervals. In this case as well, all of these concentric circles Ca may be formed by only one of the convex portions 80A, 80B, 80C, 80D, or the convex portions 80A, 80B, 80C, 80D. These concentric circles Ca may be formed by a combination of two or more of them. Further, in FIG. 12C, the convex portions 80A, 80B, 80C, and 80D are provided at predetermined intervals along the line L2 extending radially. Also in this case, all of these lines L2 may be formed by only one of the convex portions 80A, 80B, 80C, 80D, or two of the convex portions 80A, 80B, 80C, 80D. These radial lines L2 may be formed by one or more combinations.

As described above, according to the present embodiment, the uneven portion 80 for controlling the surface shape of the high heat resistant antireflection film 30 to adjust the optical performance of the high heat resistant antireflection film 30 is the lens 13 (14). Since it is provided on the surface of -17), the uneven portion 80 can affect the surface morphology of the high heat resistant antireflection film 30, and specifically, for example, the surface morphology of the high heat resistant antireflection film 30 can be set on the lens surface. The shape can be made according to the shape of the uneven portion 80, and the height H and the pitch P of the concave-convex form C1 on the surface of the highly heat-resistant antireflection film can be optimally adjusted by the uneven portion 80. Therefore, if the uneven portion 80 on the lens surface is formed so as to be suitable for the desired optical conditions and the height H and the pitch P of the concave-convex form C1 of the highly heat-resistant antireflection film 30 are optimized, the reflection is performed to a desired degree. It is possible to reduce the rate and angle of incidence dependence (for example, with respect to the angle of incidence dependence, the optical path difference between the straight light incident parallel to the optical axis and the oblique light forming an angle with respect to the optical axis is averaged. It is also possible to offset). Further, such an uneven portion 80 on the lens surface capable of adjusting the surface unevenness form C1 of the high heat resistant antireflection film 30 has an anchor effect (the unevenness between the lens 13 (14-17) and the high heat resistant antireflection film 30). It is also possible to improve the adhesion of the highly heat-resistant antireflection film 30 to the lens 13 (14-17).

Further, as in the present embodiment, the water-repellent film 50A or the water-repellent film 50A or the like on the high heat-resistant antireflection film 30 having an excellent antireflection property having a surface forming the unevenness form C1 as described above due to the uneven portion 80 on the lens surface. If the hydrophilic film 50B is provided, the water-repellent performance or the hydrophilic performance of the water-repellent film 50A or the hydrophilic film 50B can be improved. Further, in this case, the water-repellent film 50A or the hydrophilic film 50B formed on the high heat-resistant antireflection film 30 can act as a protective film for the high heat-resistant antireflection film 30. That is, the highly heat-resistant antireflection film 30 having weak scratch resistance can be protected by the water-repellent film 50A or the hydrophilic film 50B, and the film strength can be increased.

Further, in the present embodiment, the uneven portion 80 on the surface of the lens 13 (14-17) is the distance P between the vertices of the convex portions 30a, 30a constituting the uneven portion C1 on the surface of the high heat resistant antireflection film 30. The average value is 100 to 400 nm (preferably 150 to 300 nm), or the average value of the height H of the convex portion 30a is 30 to 120 nm (preferably 50 to 100 nm), or even more. It is formed so that the H / P is 0.3 to 1.3. When the H / P is set to 0.3 to 1.3 in this way, it is possible to effectively prevent foreign matter containing water droplets from staying in the concave portion 30b of the concave-convex form C1 on the surface of the highly heat-resistant antireflection film. Further, when the average value (mean pitch P) of the inter-vertex distances P between the convex portions 30a and 30a on the surface of the high heat resistant antireflection film 30 is set to 400 nm or less, which is smaller than the wavelength of visible light, it is good over the entire visible light. In addition to exhibiting excellent antireflection characteristics, it is possible to effectively prevent foreign matter containing water droplets from staying in the recess 30b. Further, by setting the average pitch P to 100 nm or more, the fluidity of the water droplets described above can be enhanced. Further, by setting the average height H of the convex portion 30a to 50 to 200 nm in addition to the average pitch P of 100 to 400 nm (or regardless of the average pitch P), the uneven portion 80 on the lens surface and high heat resistance are obtained. The concavo-convex structure composed of the concavo-convex form C1 on the surface of the antireflection film can effectively fulfill the above-mentioned function as the antireflection film.

Further, in the present embodiment, since the high heat resistant antireflection film 30 is directly formed on the surface of the lens 13 (14-17) made of resin, the high heat resistant antireflection film 30 has flexibility and flexibility. As a result, it is possible to prevent the high heat resistant antireflection film 30 from cracking at high temperatures. In this case, the air layer forming the highly heat-resistant antireflection film 30 is formed between a plurality of adjacent inorganic particles (for example, it is not formed in a portion such as a hollow portion of hollow silica fine particles), and thus is high. Even if the lens on which the heat-resistant antireflection film 30 is formed expands or contracts due to a temperature change, the high heat-resistant antireflection film 30 can follow it (in contrast, the air layer is a hollow portion of hollow silica fine particles, for example. When the base material on which the high heat resistant antireflection film is formed expands or contracts due to temperature changes, if it is formed in a part such as, and is confined inside a hard silica shell, high heat resistant antireflection is prevented. The membrane cannot follow it). Therefore, there is no possibility that the highly heat-resistant antireflection film 30 will be destroyed.

Although one embodiment of the present invention has been described above, the present invention can be variously modified and implemented without departing from the gist thereof. For example, in the present invention, the shapes of the lens, the lens barrel, the uneven portion, and the like are not limited to the above-described embodiment. Further, the form of forming the highly heat-resistant antireflection film on the lens may be any form as long as it has the above-mentioned function. In addition, a part or all of the above-described embodiments may be combined within a range that does not deviate from the gist of the present invention, or a part of the configuration may be omitted from one of the above-described embodiments. May be good.

11 Lens unit 12 Lens barrel 13, 14, 15, 16, 17 Lens (lens with film)
30 High heat resistant antireflection film 30a Convex part 50A Water repellent film 50B Hydrophilic film 80 Concavo-convex part 300 Camera module

Claims (9)

A lens with a film that is provided on the lens barrel and has an antireflection film formed on its surface.
The antireflection film is provided as a high heat resistant antireflection film, and the high heat resistant antireflection film is formed by a plurality of inorganic particles having a volume ratio of 5 to 74% in the high heat resistant antireflection film and adjacent inorganic particles. It binds the inorganic particles or the inorganic particles and the air layer to an air layer formed between the particles and having a volume ratio of 65% or less, has a Younger ratio lower than that of the inorganic particles, and has a volume ratio of 5 to 5. With any of organic compounds, inorganic compounds and inorganic polymers, which is 95%,
A lens with a film, characterized in that the surface of the lens is provided with an uneven portion for controlling the surface shape of the high heat resistant antireflection film and adjusting the optical performance of the high heat resistant antireflection film. A lens with a film that is provided on the lens barrel and has an antireflection film formed on its surface.
The antireflection film is provided as a high heat resistant antireflection film, and the high heat resistant antireflection film is composed of a fine particle laminated thin film having voids, and the fine particle laminated thin film is laminated on a lens by alternately adsorbing an electrolyte polymer and fine particles. Combined in state,
A lens with a film, characterized in that the surface of the lens is provided with an uneven portion for controlling the surface shape of the high heat resistant antireflection film and adjusting the optical performance of the high heat resistant antireflection film. The surface of the highly heat-resistant antireflection film has a concavo-convex shape substantially following the shape of the concavo-convex portion on the surface of the lens, and the average value of the distances between the vertices of the convex portions constituting the concavo-convex shape is 100 to 400 nm. The lens with a film according to claim 1 or 2, wherein the uneven portion on the surface of the lens is formed so as to be the same. The surface of the highly heat-resistant antireflection film has a concavo-convex shape substantially following the shape of the concavo-convex portion on the surface of the lens, and the average height of the convex portions constituting the concavo-convex shape is 30 to 120 nm. The lens with a film according to any one of claims 1 to 3, wherein the uneven portion on the surface of the lens is formed. The surface of the highly heat-resistant antireflection film has a concavo-convex shape substantially following the shape of the concavo-convex portion on the surface of the lens, and the average value of the distances between the apexes of the convex portions constituting the concavo-convex shape is P, and the convex portion. The present invention according to claim 1 or 2, wherein the uneven portion on the surface of the lens is formed so that the H / P is 0.3 to 1.3, where H is the average value of the heights of the lenses. Lens with film. The lens with a film according to any one of claims 1 to 5, wherein a water-repellent film or a hydrophilic film is provided on the antireflection film. The lens with a film according to claim 6, wherein the water-repellent film or the hydrophilic film is provided in a shape substantially conforming to the uneven shape on the surface of the highly heat-resistant antireflection film. A lens unit including a lens group in which a plurality of lenses are arranged along the optical axis of the lens and a lens barrel in which the lens group is housed.
A lens unit according to any one of claims 1 to 7, wherein at least one of the lenses constituting the lens group is a lens with a film. A camera module including the lens unit according to claim 8.

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