JP6899701B2 - Manufacturing method of lens unit, camera module and first lens - Google Patents

Description

The present invention 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 further applications to automatic driving have been attempted.
A camera module such as an in-vehicle camera generally includes a lens group consisting of a plurality of lenses in which a plurality of lenses are arranged along an optical axis, a lens barrel in which the lens group is housed, and a lens group. It includes a lens unit having an aperture member arranged between at least one lens.

As an example of the conventional lens unit, the one described in Patent Document 1 is known. In this lens unit, four lenses are held in a state in which they are arranged in a row with their optical axis directions aligned with each other in the lens barrel.
When such a lens unit is used in an in-vehicle camera, water droplets may adhere to the lens surface exposed from the lens barrel in rainy weather. Since water droplets adhering to such a lens surface cause image deterioration, for example, to prevent water droplets from adhering, water is repelled on the lens surface exposed from the lens barrel (the lens surface of the lens on the object side located closest to the object side). By providing the film, the water droplets adhering to the lens surface are allowed to flow toward the outer peripheral side on the water-repellent film of the lens surface so that the water droplets adhering to the lens surface do not stay in the place.

Japanese Unexamined Patent Publication No. 2013-231993

By the way, the lens (object side lens) located closest to the object side of the lens barrel is fixed to the object side end portion of the lens barrel by a caulking portion (fixed portion) formed by caulking the object side end portion of the lens barrel. Therefore, the crimped portion is in contact with the outer peripheral edge portion of the lens surface. For this reason, a step is generated between the crimped portion and the outer peripheral edge portion of the lens surface, and water droplets flowing toward the outer peripheral side on the water-repellent film are accumulated in this step, which reduces visibility. was there.

The present invention has been made in view of the above circumstances, and is a lens with a film, a lens unit, and a camera that can prevent deterioration of visibility by preventing the retention of water droplets flowing toward the outer peripheral side of the lens surface. The purpose is to provide a module.

In order to solve the above problems, the lens with a film of the present invention is a lens that is fixed to the end of the lens barrel on the object side by a fixing portion provided at the end of the lens barrel on the object side and faces the object side. It is a lens with a film with a film on the surface.
A water-repellent film is provided on the entire lens surface.
The surface of the water-repellent film is characterized in that a hydrophilic film is provided on at least the surface radially inner of the outer peripheral edge of the contact where the fixing portion contacts.

Here, the water-repellent film is a thin film having water repellency, and means a film having a contact angle of water droplets with respect to the water-repellent film of 90 degrees or more.
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.
The contact angle shall be measured by using the static drip method (A, half-angle, Method), and 2.5 microliters of water droplets are dropped onto the lens surface on which the film is formed so as not to be affected by the lens surface. However, the curved surface connecting the left and right end points of the droplet is regarded as a straight line, and the contact angle of the water droplet is measured.
Further, since the hydrophilic film may be provided on the surface of the water-repellent film at least radially inside the outer peripheral edge of the contact where the fixing portion contacts, the hydrophilic film may be provided on the entire surface of the water-repellent film. It may be provided on the surface including the outer peripheral edge of the contact and radially inside the outer peripheral edge of the contact. Further, the hydrophilic film may not be provided at the radial center portion of the water repellent film.

In the present invention, since the hydrophilic film is provided on the surface of the water-repellent film on the inner surface in the radial direction from at least the contact outer peripheral edge portion with which the fixing portion contacts, the water-repellent film is directed toward the outer peripheral side. The flowing water droplets spread on the hydrophilic film provided on the inner surface in the radial direction from the outer peripheral edge of the contact to form a thin water film, and form a step between the fixed portion and the outer peripheral edge of the lens surface. Does not stay as water droplets. Therefore, it is possible to prevent the retention of water droplets that have flowed toward the outer peripheral side of the surface of the water-repellent film on the lens surface, and thus it is possible to prevent deterioration of visibility.

Further, in the configuration of the present invention, assuming that the radial radius of the lens surface inside the outer peripheral edge of the contact in the radial direction is the exposure radius.
The hydrophilic film may be provided radially inside the outer peripheral edge of the contact with a length of 5% or more of the exposure radius.

According to such a configuration, it is possible to more effectively prevent the water droplets that have flowed toward the outer peripheral side of the surface of the water-repellent film from staying as water droplets on the step.

Further, the lens unit according to the present invention is 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.
The lens with a film is provided at the opening on the object side of the lens barrel, and the lens with a film is fixed to the end of the lens barrel by a fixing portion provided at the end of the lens barrel on the object side. It is characterized by being.

In the present invention, the water droplets that have flowed toward the outer peripheral side of the surface of the water-repellent film on the step generated between the fixed portion and the outer peripheral edge of the lens surface of the lens with the film have a diameter larger than that of the outer peripheral edge of the contact. It spreads on the hydrophilic film provided on the inner surface in the direction to form a thin water film, and does not stay as water droplets on the step. Therefore, it is possible to prevent the retention of water droplets that have flowed toward the outer peripheral side of the surface of the water-repellent film on the lens surface, and thus it is possible to prevent deterioration of visibility.

Further, the camera module according to the present invention is characterized by including the lens unit.
According to such a configuration, the action and effect of the above-mentioned lens unit can be obtained by the camera module.

According to the present invention, the water droplets flowing on the water-repellent film toward the outer peripheral side do not spread on the hydrophilic film provided on the inner surface in the radial direction from the outer peripheral edge portion of the contact and do not stay as water droplets. Therefore, it is possible to prevent the retention of water droplets that have flowed toward the outer peripheral side of the lens surface, and thus it is possible to prevent a decrease in visibility.

A lens unit according to an embodiment of the present invention is shown, and is a schematic cross-sectional view thereof. It is a plan view of the lens with a film. The same is a schematic cross-sectional view of the main part. It is a process drawing for demonstrating the manufacturing method of the lens with a film which concerns on this Embodiment, (a) is the figure which shows the state which fixed the lens body to a lens holder, (b) was filled with an acrylic polymer liquid. The figure which shows the state which the lens holder was immersed in the container, (c) is the figure which shows the state which took out the lens holder from a container, (d) is the figure which shows the schematic structure of the lens unit with a film. It is the schematic sectional drawing which shows the camera module which concerns on embodiment in this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The lens unit of the present embodiment is 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 the wiring is drawn into the automobile and connected to a display or other device. Will be done.
Note that in FIGS. 1, 3 and 5, hatching is omitted for the plurality of lens members, and some of them are broken.

As shown in FIG. 1, the lens unit 11 of the present embodiment includes a cylindrical lens barrel 12 and a plurality of (for example, four) lenses 13, 14, 15, 18 arranged in the lens barrel 12. It includes two drawing members 22a and 22b. An in-vehicle camera including the 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, and 18 fixed and supported by the lens barrel 12 are arranged in a state in which their respective optical axes are aligned with each other, and each lens 13 and 13 are arranged along one optical axis O. 14, 15, and 18 are arranged side by side to form a group of lenses used for imaging. Further, the lens 18 is a bonded lens 18, and the lens 16 and the lens 17 are bonded to each other with an adhesive. Further, the lens 13 is a lens 13 with a film as described later. In the following, the lens 13 may be referred to as a lens with a film 13.

Of the two diaphragm members 22a and 22b, the first diaphragm member 22a from the object side is arranged between the second lens 14 and the third lens 15 from the object side. The second aperture member 22b from the object side is arranged between the third lens 15 and the fourth lens 16 from the object side. The diaphragm members 22a and 22b are 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. ..

A crimped portion (fixed portion) 23 is provided at the end portion (upper end portion in FIG. 1) of the lens barrel 12 on the object side, and the end portion is crimped to the inner diameter side. 13 is fixed to the end of the lens barrel 12 on the object side. The lens body other than the film of the lens 13 with a film is a glass lens, but a resin lens may be used.
Further, a flange portion 24 having an opening having a diameter smaller than that of the bonded lens 18 is provided at an end portion (lower end portion in FIG. 1) of the lens barrel 12 on the image plane side. The flange portion 24 and the caulking portion 23 hold a plurality of lenses 13, 14, 15, 18 and diaphragm members 22a, 22b forming a lens group in the lens barrel 12. When fixing the lens 13 with a film, the lens 13 is not limited to the crimped portion 23, but is a fixed portion attached to the end of the lens barrel 12 on the object side after the lenses 13, 14, 15, and 18 are stored in the lens barrel 12. There may be.

On the outer peripheral surface of the lens 13 with a film on the most object side, a reduced diameter portion having a smaller diameter is provided on the image surface side portion of the lens 13 with a film, and an O-ring 26 as a sealing member is provided on the reduced diameter portion. It is provided so that the outer peripheral surface of the lens 13 with a film 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. A cylindrical inner wall 12b is provided inside the lens barrel 12 on the object side, an annular body 27 is provided between the inner wall 12b and the outer wall 12a, and the O-ring 26 is in close contact with the annular body 27. There is.

The inner diameter of the lens barrel 12 gradually decreases from the object side to the image plane side. Correspondingly, the outer diameters of the lenses 13, 14, 15, and 18 become smaller from the object side toward the image plane side. Basically, the outer diameters of the lenses 13, 14, 15, and 18 are substantially equal to the inner diameters of the portions of the lens barrel 12 on which the lenses 13, 14, 15, and 18 are supported. On the outer peripheral surface of the lens barrel 12, a flange portion 25 used when the lens barrel 12 is installed on the vehicle-mounted camera is provided on the outer peripheral surface of the lens barrel 12 in a flange shape.

Further, as shown in FIGS. 1 to 3, the lens surface 13a of the lens 13 with a film facing the object side is formed in an arcuate shape convex toward the object side in a cross-sectional view, and the lens surface 13a is formed on the lens surface 13a. An antireflection film (AR coating) (not shown) is provided on the entire surface. Further, a water repellent film 20 is provided on the antireflection film by vapor deposition. The water-repellent film 20 is formed of a fluororesin, and the film thickness is set to 2 to 200 nm, but in the present embodiment, it is about 20 nm.

A hydrophilic film 21 is provided on the surface of the water-repellent film 20 at least radially inside the outer peripheral edge portion 20a in which the crimped portion 23 is in contact. Specifically, as shown in FIGS. 1 and 2, if the radial radius of the lens surface 13a inside the outer peripheral edge portion 20a in the radial direction is the exposure radius r, the hydrophilic film 21 is from the outer peripheral edge portion 20a in contact. It is provided on the inner side in the radial direction with a length L of 5% or more of the exposure radius r. In the present embodiment, the hydrophilic film 21 extends from the outer peripheral edge of the lens surface 13a beyond the contact outer peripheral edge portion 20a and the tip edge 23a of the caulking portion 23, and extends radially inward from the tip edge 23a by a length of L. ing.
The hydrophilic film 21 is formed of an acrylic polymer and the film thickness is set to 2 to 200 nm, but in the present embodiment, it is about 20 nm, which is the same thickness as the water repellent film 20.

The hydrophilic film 21 of the lens 13 with a film may be formed as follows, for example.
That is, first, as shown in FIG. 4A, the lens body 13A provided with the antireflection film and the water repellent film 20 not shown on the lens surface 13a is attached to the lens holder 30 for film formation. The lens body 13A is described as deformed.
The lens holder 30 has a fixed surface 30a for fixing the surface of the lens body 13A facing the lens surface 13a and an outer peripheral edge of the water-repellent film 20 on the lens surface 13a of the lens body 13A fixed to the fixed surface 30a. It is provided with a support portion 30c having a mask surface 30b that is in close contact with the surface of the central portion to be removed and covers the surface of the central portion.
The mask surface 30b is in close contact with the non-formed surface of the water-repellent film 20 that does not form the hydrophilic film 21. The forming surface on which the hydrophilic film 21 should be formed is a substantially ring-shaped surface of the outer peripheral edge portion of the surface of the water-repellent film 20, and the mask surface 30b is in close contact with the surface (non-forming surface) radially inside from this forming surface. ing.
Further, cavities 30d and 30d for exposing the forming surface on which the hydrophilic film 21 should be formed are provided inside the lens holder 30, and the cavities 30d and 30d communicate with the outside of the lens holder 30. There is.

Next, as shown in FIG. 4B, the lens holder 30 to which the lens body 13A is fixed is immersed in a container 31 filled with a paint PL made of an acrylic polymer solution. As a result, the hollow portions 30d and 30d of the lens holder 30 are filled with the paint PL, and the paint PL adheres to the formed surface exposed in the hollow portions 30d and 30d.
Then, after immersing the lens holder 30 in the container 31 for a predetermined time, as shown in FIG. 4C, the lens holder 30 is taken out from the container 31 and heat-treated. As a result, a hydrophilic film 21 made of an acrylic polymer is formed on the forming surface.
Finally, as shown in FIG. 4D, the lens 13 with a film can be obtained by taking out the lens body 13A from the lens holder 30.

FIG. 5 is a schematic cross-sectional view of the camera module 300 of the present embodiment. As shown in FIG. 5, the camera module 300 includes a lens unit 11 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 (flange, 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 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 upper case 301 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 collected through the lens unit 11 and reached 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.

As described above, according to the present embodiment, as shown in FIG. 3, the hydrophilic film 21 is on the surface of the water-repellent film 20 on the inner surface in the radial direction from the outer peripheral edge portion 20a in which at least the crimped portion 23 is in contact. Is provided, so that the water droplet wd that has flowed toward the outer peripheral side on the water-repellent film 20 spreads on the hydrophilic film 21 provided on the surface radially inside from the outer peripheral edge portion 20a of the contact, and is thin water. It becomes the film wf and does not stay as water droplets wd on the step formed between the caulking portion 23 and the outer peripheral edge portion of the lens surface 13a. Therefore, it is possible to prevent the water droplets wd that have flowed toward the outer peripheral side of the surface of the water-repellent film 20 on the lens surface 13a from staying, so that the visibility can be prevented from being lowered.

Further, assuming that the radial radius of the lens surface 13a radially inside the contact outer peripheral edge portion 20a is the exposure radius r, the hydrophilic film 21 has a length of 5% or more of the exposure radius radially inside the contact outer peripheral edge portion 20a. Therefore, it is possible to more effectively prevent the water droplets that have flowed toward the outer peripheral side of the surface of the water-repellent film 20 from staying as water droplets on the step.
Further, when the surface of the lens unit 11 is rubbed with a cleaning tool such as a scrubbing brush or a brush in order to remove dust and dirt adhering to the surface exposed to the outside of the lens 13 with a film, the outer peripheral edge is removed. The hydrophilic film 21 provided in the portion is less likely to be hit by a cleaning tool than the water-repellent film 20 provided in the central portion. Therefore, the hydrophilic film 21 is less likely to be scratched as compared with the case where the hydrophilic film is provided on the entire surface of the lens surface 13a.
Further, since the camera module 300 includes the lens unit 11, the effects of the film-attached lens 13 of the lens unit 11 can be obtained by the camera module 300.

In the present embodiment, the hydrophilic film 21 is provided on the outer peripheral edge of the surface of the water-repellent film 20, but the hydrophilic film 21 may be provided on the entire surface of the water-repellent film 20. In this case, the central portion of the hydrophilic film 21 may be peeled off by the cleaning tool as described above, but even if the hydrophilic film 21 is peeled off, the water-repellent film 20 is only exposed on the peeled-off portion. Since it is possible to prevent the retention of water droplets that have flowed toward the outer peripheral side of the surface of the water-repellent film 20, it is possible to prevent a decrease in visibility.

11 Lens unit 12 Lens barrel 13 Lens with film 13a Lens surface 20 Water-repellent film 20a Outer peripheral edge of contact 21 Hydrophilic film 23 Caulking part (fixed part)
300 camera module

Claims (4)

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.
The first lens on the object side of the lens group is crimped by a caulking portion provided at the end of the lens barrel on the object side and fixed to the end of the lens barrel.
A water-repellent film is provided on the entire lens surface on the object side of the first lens.
Of the surface of the water-repellent film, an annular hydrophilic film is formed on the surface radially inside from the outer peripheral edge of the water-repellent film, at least beyond the outer peripheral edge of the contact where the caulked portion contacts. A lens unit characterized by being provided with. When the radial radius of the lens surface inside the outer peripheral edge of the contact is taken as the exposure radius.
The lens unit according to claim 1, wherein the hydrophilic film is provided radially inside the outer peripheral edge of the contact with a length of 5% or more of the exposure radius. A camera module including the lens unit according to claim 1 or 2. A method for manufacturing a first lens, which is fixed to the end of the lens barrel on the object side by a caulking portion provided at the end of the lens barrel on the object side, and has a film on the lens surface facing the object. ,
Prepare a lens body with a water-repellent film on the entire lens surface, and
A fixed surface for fixing the surface of the lens body facing the lens surface, and
A lens holder provided with a mask surface provided on the lens surface, which is in close contact with the surface of the central portion excluding the outer peripheral edge portion of the water-repellent film and covers the surface of the central portion, is prepared.
Inside the lens holder, a cavity for exposing the forming surface on which the hydrophilic film should be formed is provided, and the cavity communicates with the outside of the lens holder.
When fixing the lens body provided with the water-repellent film on the lens surface to the lens holder,
The mask surface is brought into close contact with the non-formed surface that does not form the hydrophilic film, which is the surface of the central portion excluding the outer peripheral edge of the water-repellent film, and the surface facing the lens surface is fixed to the fixed surface.
Next, the lens holder to which the lens body is fixed is immersed in a container filled with a paint made of an acrylic polymer solution, and the cavity portion of the lens holder is filled with the paint to form the cavity. The paint is adhered to the formed surface exposed on the portion, and the paint is adhered to the formed surface.
Next, the lens holder is taken out from the container and heat-treated to form a hydrophilic film made of an acrylic polymer on the forming surface.
The hydrophilic film is provided on the surface of the water-repellent film in an annular shape from the outer peripheral edge of the water-repellent film beyond at least the outer peripheral edge of contact where the crimped portion contacts.
Finally, a method for manufacturing a first lens, which comprises taking out the lens body from the lens holder.

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