WO2014188943A1

WO2014188943A1 - Lens unit and optical unit

Info

Publication number: WO2014188943A1
Application number: PCT/JP2014/062919
Authority: WO
Inventors: 和夫柴
Original assignee: 日本電産サンキョー株式会社
Priority date: 2013-05-20
Filing date: 2014-05-15
Publication date: 2014-11-27
Also published as: JP6174904B2; JP2014228587A; TWI519837B; TW201502632A

Abstract

Provided are a lens unit and an optical unit having high airtightness and having high lens fixing strength. The lens unit (100) has multiple lenses (1-4) arranged along the optical axis (L) of the lens unit, and a tubular holder (7) that holds these lenses (1-4). A convex lens surface (1a) is formed on the lens (1), and the lens surface (1a) protrudes from a large-diameter part (74) provided at the foremost end of the holder (7), and is secured by crimping. A continuous coating is applied to the lens surface (1a) and the surface of a crimping part (76) around the periphery of the lens surface. The process for coating the lens surface (1a) is performed with the lens (1) secured by crimping in the holder (7), so the gap between the lens surface (1a) and the crimping part (76) is sealed by the coating material, thereby improving airtightness.

Description

Lens unit and optical unit

The present invention relates to a lens unit in which a plurality of lenses are held by a cylindrical lens holder, and an optical unit including the lens unit.

In a lens unit in which a plurality of lenses are held in a cylindrical lens holder, an airtightness of the lens unit is improved by incorporating an O-ring between the lens arranged on the forefront side of the subject and the lens holder, It prevents foreign matter and moisture from entering the lens unit. Patent Document 1 discloses an imaging unit using this type of lens unit.

Conventionally, the surface of the lens incorporated in the lens unit is coated, and a thin film having an optical function such as antireflection, a surface reinforcing function such as scratch prevention, and a water repellent function is formed. This type of coating is applied by various methods such as vapor deposition, coating, and spin coating. Here, when a coating is applied to the surface of the lens of the lens unit, the coating is usually performed on the lens itself, and the coated lens is assembled to the holder, but as described in Patent Document 2 It has also been proposed that after the lens is attached to a holding member (lens holder), the integrated lens and the holding member are set on a spin coater to perform spin coating. In this way, it is possible to prevent the coating material from adhering to the back side of the lens and improve the uniformity of the film thickness.

JP 2009-265473 A International Publication No. 2008/062817

As in Patent Document 1, in the structure in which the air tightness of the lens unit is ensured by the O-ring, there is a possibility that foreign matter or water may enter the gap on the front side (subject side) from the O-ring. In addition, when the O-ring is assembled, there is a risk that foreign matter may adhere to the O-ring or the O-ring itself may be deformed, resulting in a loss of airtightness. If the airtightness is impaired, water droplets or foreign matter enter between the plurality of lenses, and the optical performance is remarkably deteriorated so that the function cannot be maintained.

Further, in the lens unit in which the lens is assembled to the lens holder, if the lens is loosely fixed to the lens holder, not only the airtightness is impaired, but also the accuracy of the optical system composed of a plurality of lenses is reduced, and the lens The optical performance of the unit may be degraded.

On the other hand, in Patent Document 2, spin coating is performed after the lens is attached to a holding member (lens holder), and an optical thin film is formed on the surfaces of the lens and the holding member. For this reason, the gap between the lens and the holding member can be covered with the optical thin film, and the airtightness of the lens unit is improved. However, in Patent Document 2, the coating material is prevented from accumulating at the boundary between the lens and the holding member, and the coating material that seals the gap is thin, so that the airtightness may not be sufficient.

Further, in the lens unit of Patent Document 2, the lens is disposed at the bottom of the concave portion provided in the holding member. With such a shape, it may be difficult to apply the coating only in a necessary range. For example, in dip coating, coating may be performed over an unnecessarily wide range, which may increase costs.

In view of the above problems, an object of the present invention is to provide a lens unit and an optical unit with high airtightness and high lens fixing strength easily and at low cost.

In order to solve the above problems, a lens unit according to the present invention includes a plurality of lenses arranged along an optical axis, and a cylindrical lens holder that holds the plurality of lenses, and the plurality of lenses. Includes a first lens having a convex lens surface, and the first lens has the lens holder in a state in which at least a part of the lens surface protrudes from one end of the lens holder in the optical axis direction. The lens surface and at least a part of the surface of the lens holder surrounding the lens surface are coated with a continuous coating.

In the present invention, since the gap between the first lens and the lens holder is sealed with the coating material, the air tightness of the lens unit can be improved, and foreign matter and moisture enter the inside of the lens unit. Can be suppressed. In addition, since the coating material is cured, the first lens can be firmly fixed to the lens holder, and the first lens can be prevented from loosening. Therefore, it is possible to suppress a decrease in the optical performance of the lens unit. Moreover, since the lens surface protrudes from the lens holder, the coating can be easily applied to a necessary range. In addition, since the coating is performed after the assembly of the lens, it is only necessary to apply the coating to non-defective products that have passed the inspection, so that the workload of the coating can be reduced and the coating material can be saved. Also, the surface of the lens holder can be protected by the coating material.

In the present invention, the lens holder is provided with a caulking portion for caulking and fixing an outer peripheral portion of the first lens, and the coating is formed on the lens surface and the surface of the lens holder including the surface of the caulking portion. It is desirable that it is continuously applied to at least a part. In this way, the fixing strength of the first lens can be increased by caulking, and the gap between the caulking portion and the first lens can be sealed by the coating material. Therefore, airtightness can be improved, and entry of foreign matter and moisture can be suppressed.

In the present invention, it is preferable that a boundary portion between the caulking portion and the lens surface is a liquid reservoir portion in which a coating material is accumulated. In this case, since the boundary portion can be thickly coated, the gap between the caulking portion and the lens can be more reliably sealed, and airtightness can be further improved. Therefore, intrusion of foreign matter, moisture, and the like can be more reliably suppressed.

In this case, it is desirable that the caulking portion is provided on the entire circumference of the first lens. By doing so, the entire circumference of the first lens can be fixed by caulking, and the fixing strength is further increased. In addition, since the liquid reservoir portion where the coating material is accumulated is formed on the entire circumference of the first lens, the airtightness is further improved.

In addition, it is desirable that the lens surface and the caulking portion are formed so that the outer peripheral side of the lens surface is closer to the liquid reservoir than the effective diameter of the lens. In this way, the coating material collected in the liquid reservoir does not affect the optical performance.

Here, in the present invention, the inner surface of the lens holder is formed with a positioning portion where the first lens abuts in the optical axis direction, and the caulking portion is located between the positioning portion and the first lens. It is desirable to crimp the outer periphery. In this way, even if the coating material enters the lens holder from the boundary between the crimping portion and the lens surface, the positioning portion becomes a liquid reservoir for the coating material, and the coating material is prevented from entering inside the positioning portion. Is done. Therefore, there is little possibility that a problem occurs due to the coating material that has entered the lens holder. In addition, since the gap between the positioning portion and the first lens can be sealed by the coating material accumulated in the positioning portion, the airtightness is further improved. In addition, the fixing strength of the first lens is further increased.

In the present invention, it is desirable to have an O-ring disposed between the first lens and the lens holder. If it does in this way, since airtightness can be improved not only by a coating material but by an O-ring, airtightness can be improved more.

In the present invention, it is desirable that a step is formed on the outer peripheral surface of the lens holder. In this case, since the step portion becomes a liquid pool portion, it is possible to prevent excessive coating material from dripping over the outer peripheral surface of the lens holder over a wide range.

Next, an optical unit of the present invention includes the lens unit described above and a holding member that holds the lens unit, and the holding member is an end of the lens holder on the side on which the first lens is fixed. And the coating applied to the lens surface and the surface of the lens holder in the lens unit is continuously applied to at least a part of the surface of the holding frame. Yes.

In the present invention, since the gap between the lens unit and its holding member is also covered with the coating, the optical unit is highly airtight and the fixing strength of the lens unit 100 is also high. Therefore, it is possible to suppress problems due to intrusion of foreign matter and moisture, and it is possible to suppress deterioration of optical performance.

According to the present invention, since the gap between the first lens and the lens holder is sealed with the coating material, the air tightness of the lens unit can be improved, and foreign matter and moisture can be prevented from entering the lens unit. . In addition, since the coating material is cured, the first lens can be firmly fixed to the lens holder, and the first lens can be prevented from loosening. Therefore, it is possible to suppress a decrease in the optical performance of the lens unit. Moreover, since the lens surface protrudes from the lens holder, the coating can be easily applied to a necessary range. In addition, by applying the coating after the lens is assembled, it is possible to apply the coating only to a non-defective product that has passed the inspection, thereby reducing the work load of the coating and saving the coating material. Also, the surface of the lens holder can be protected by the coating material.

It is sectional drawing of the lens unit which concerns on embodiment of this invention. It is explanatory drawing which extracts and shows the shaping | molding lens and aperture_diaphragm | restriction in a lens unit. It is a partial expanded sectional view of a lens unit. It is explanatory drawing of the optical unit which concerns on embodiment of this invention.

Hereinafter, a lens unit and an optical unit to which the present invention is applied will be described with reference to the drawings.

DESCRIPTION OF SYMBOLS 1

Lens

1a, 1b Lens surface 1c Annular surface 2

Lens

2a, 2b Lens surface 3

Lens

3a, 3b Lens surface 4

Lens

4a, 4b Lens surface 5 Aperture 6 Infrared filter 6a Object side surface 6b Image side surface 7 Holder 7a Object side opening 7b Image side opening portion 21 Flange portion 22 Step portion 31 Flange portion 41 Flange portion 45 Step portion 46 Molded

lenses

46a and 46b Lens surface 47 Molded

lenses

47a and 47b Lens surface 71 Bottom plate portion 72 Cylindrical body portion 73 Flange portion 74 Large diameter portion 75 Step portion 76 Caulking portion 77 Groove 78 O-ring 79 Step portion 80

Thin film

81, 82, 83 Liquid pool portion 100 Lens unit 110 Outer reference surface 200 Optical unit 201 Device case 202 Holding frame 203

Inner surfaces

210, 310, 410 Outer reference surface 460 Flange 470 Flange 720 Inner surface 721 Step 740 Surface L device optical axis L1 object side L2 image side

(Lens unit)
FIG. 1 is a cross-sectional view of a lens unit according to an embodiment of the present invention, and FIG. 2 is an explanatory view showing a molded lens and a diaphragm extracted from the lens unit. In FIG. 1, a thin film 80 to be described later is not shown. The lens unit 100 of the present embodiment includes a plurality of

lenses

1, 2, 3, 4 and an infrared filter 6 disposed along the device optical axis L, and the

lenses

1, 2, 3, 4 and infrared rays. The filter 6 is held by a cylindrical holder 7. In addition, a diaphragm 5 is disposed between the lens 3 and the lens 4 inside the holder 7. In this embodiment, among the

lenses

1, 2, 3, 4 and the infrared filter 6, the lens 1 located closest to the object side L 1 is the object side opening 7 a of the holder 7 (the front end opening of the large diameter portion 74 described later). It is arranged to close up. On the other hand, the infrared filter 6 located closest to the image side L2 is disposed so as to block an image side opening 7b (an opening formed in a bottom plate 71 described later) of the holder 7. The number of lenses is not limited to such a number, but may be other numbers. Further, the infrared filter 6 may not be provided.

The holder 7 is a resin cylinder. In addition, not only resin but metal, such as aluminum, may be sufficient. The holder 7 includes a perforated bottom plate portion 71 positioned on the most rear side (image side L2) in the apparatus optical axis L direction, and a cylindrical body portion extending from the outer periphery of the bottom plate portion 71 to the front side (object side L1). 72, a flange portion 73 formed on the outer peripheral side of the front end portion of the cylindrical body portion 72, and a cylindrical large-diameter portion 74 extending from the flange portion 73 to the front side (object side L1). . Inside the holder 7, the inner surface 740 of the large diameter portion 74 is larger in diameter than the inner surface 720 of the cylindrical body portion 72.

In the holder 7, the

lenses

2, 3, 4 are arranged with reference to the inner surface 720 of the cylindrical body 72. The lens 1 (first lens) is disposed at the foremost end of the holder 7 on the object side L1 with the inner surface 740 of the large diameter portion 74 as a reference. The lens 1 is arranged such that the lens surface 1a on the object side L1 has a convex shape, and at least a part of the lens surface 1a protrudes from the front end of the holder 7 toward the object side L1. In this embodiment, the lens 1 is arranged at the foremost end of the holder 7, and most of the lens surface 1 a protrudes from the front end of the holder 7 toward the object side L <b> 1. On the other hand, at the rear end of the holder 7, the object side surface 6 a of the infrared filter 6 is in contact with the image side L 2 surface of the bottom plate portion 71. The image side surface 6 b of the infrared filter 6 faces an imaging device (not shown) disposed on the rear side (image side L <b> 2) of the lens unit 100.

Lens 1 is a glass lens with negative power. As the lens 1, a plastic molded lens may be used. In the lens 1, the lens surface 1a on the object side L1 is a convex spherical surface, and the lens surface 1b on the image side L2 is a concave spherical surface. Comparing the curvature radii of the lens surfaces 1a and 1b, the curvature radius of the lens surface 1b is smaller than the curvature radius of the lens surface 1a. The outer peripheral surface of the lens 1 is an outer peripheral reference surface 110 that is disposed with reference to the inner surface 740 of the large diameter portion 74 and defines the position of the optical axis of the lens 1.

The lens 1 is positioned in the device optical axis L direction with reference to an annular step 75 (positioning portion) provided on the front surface (object side L1) of the flange portion 73. The holder 7 is provided with a caulking portion 76 at the front end of the large diameter portion 74 for caulking and fixing the lens 1 by heat caulking. The outer peripheral portion of the lens 1 is disposed so as to contact the step portion 75 in the apparatus optical axis L direction, and the caulking portion 76 fixes the outer peripheral portion of the lens 1 with the step portion 75 by caulking. The caulking portion 76 and the stepped portion 75 are provided annularly on the entire circumference of the lens 1.

An annular groove 77 is formed at a position near the inner periphery of the stepped portion 75, and an O-ring 78 is disposed in the groove 77. In the lens 1, a flat annular surface 1c is formed on the outer periphery of the lens surface 1b on the image side L2 so as to face the stepped portion 75 in the apparatus optical axis L direction. When the lens 1 is assembled in the large-diameter portion 74 and fixed by caulking, the annular surface 1 c comes into contact (pressure contact) with the step portion 75, and an O-ring 78 is formed between the annular surface 1 c and the bottom surface of the groove 77. Compressed. As a result, the O-ring 78 is in close contact with the bottom surface of the groove 77 and the annular surface 1 c, and the gap between the lens 1 and the holder 7 is sealed by the O-ring 78.

Lens 2 is a plastic molded lens having negative power. In the lens 2, the lens surface 2a on the object side L1 is a convex spherical surface or aspheric surface, and the lens surface 2b on the image side L2 is a concave spherical surface or aspheric surface. Comparing the curvature radii of the lens surfaces 2a and 2b, the curvature radius of the lens surface 2b is smaller than the curvature radius of the lens surface 2a. The lens 2 has a flange portion 21 on the outer peripheral side of the lens surfaces 2a and 2b. A step portion 22 is formed on the surface of the flange portion 21 on the object side L1. The outer peripheral surface of the flange portion 21 is an outer peripheral reference surface 210 that is arranged with reference to the inner surface portion located on the object side L1 of the inner surface 720 of the cylindrical body portion 72 and defines the position of the optical axis of the lens 2. Yes.

Lens 3 is a plastic molded lens having a positive power. In the lens 3, the lens surface 3a on the object side L1 is a concave spherical surface or aspheric surface, and the lens surface 3b on the image side L2 is a convex spherical surface or aspheric surface. Comparing the curvature radii of the lens surfaces 3a and 3b, the curvature radius of the lens surface 3a is smaller than the curvature radius of the lens surface 3b. The lens 3 has a flange portion 31 on the outer peripheral side of the lens surfaces 3a and 3b. The outer peripheral surface of the flange portion 31 is disposed on the basis of the inner surface portion of the inner surface 720 of the cylindrical body portion 72 located in the middle of the device optical axis L direction and defines the position of the optical axis of the lens 3. 310.

Lens 4 is a cemented lens having a positive power. In the lens 4, the lens surface 4a on the object side L1 is a convex spherical surface or aspheric surface, and the lens surface 4b on the image side L2 is a convex spherical surface or aspheric surface. Specifically, the lens 4 is a cemented lens in which a plastic molded lens 46 disposed on the object side L1 and a plastic molded lens 47 disposed on the image side L2 are cemented. The lens surface 46b on the image side L2 and the lens surface 47a on the object side L1 of the molded lens 47 are joined with an adhesive. Therefore, the lens surface 4a on the object side L1 of the lens 4 is configured by the lens surface 46a on the object side L1 of the molded lens 46, and the lens surface 47b on the image side L2 of the molded lens 47 is on the image side L2 of the lens 4. A lens surface 4b is configured. Comparing the curvature radii of the

lens surfaces

46a, 46b, 47a, 47b, the curvature radii of the lens surfaces 46b, 47a are smaller than those of the

other lens surfaces

46a, 47b.

Similarly to the

lenses

2 and 3, the lens 4 has a flange portion 41 on the outer peripheral side of the lens surfaces 4 a and 4 b, and the outer peripheral surface of the flange portion 41 is an image of the inner surface 720 of the cylindrical body 72. An outer peripheral reference surface 410 that defines the position of the optical axis of the lens 4 is arranged with reference to the inner surface portion located on the side L2. In this embodiment, since the molded lens 46 has a larger diameter than the molded lens 47, the outer peripheral reference surface 410 is formed by the outer peripheral surface of the flange portion 460 of the molded lens 46. Since the flange portion 470 of the molded lens 47 has a smaller diameter than the flange portion 460, a step 45 is formed on the image side L 2 surface of the flange portion 41.

In the holder 7, a stepped portion 721 is formed on the inner surface 720 of the cylindrical body portion 72 at a position on the image side L <b> 2 near the bottom plate portion 71. When the flange portion 41 of the lens 4 abuts on the stepped portion 721, the lens 4 is positioned in the apparatus optical axis L direction. On the object side L1 of the lens 4, an aperture 5, a lens 3, and a lens 2 are superposed in this order. In this embodiment, the

lenses

2, 3, and 4 are press-fitted into the cylindrical body 72, or are inserted with a minimum gap between the inner surface 720 of the cylindrical body 72, thereby holding the holder. 7 is fixed.

Here, the outer peripheral reference surface 110 of the lens 1 is parallel to the inner surface 740 of the large diameter portion 74. When the lens 1 is disposed in the large diameter portion 74, the outer peripheral reference surface 110 is disposed with reference to the large diameter portion 74, and as a result, the position of the optical axis of the lens 1 is determined. Similarly, the outer peripheral reference surfaces 210, 310, 410 of the

lenses

2, 3, 4 are parallel to the inner surface 720 of the holder 7. When the

lenses

2, 3, 4 are arranged inside the cylindrical body 72 of the holder 7, the outer peripheral reference surfaces 210, 310, 410 are arranged with reference to the inner surface 720 of the holder 7. As a result, the positions of the optical axes of the

lenses

2, 3, and 4 are determined.

(Sealing structure with coating material)
FIG. 3 is a partial enlarged cross-sectional view of the lens unit 100 (enlarged view of the region A in FIG. 1). In the lens unit 100, a hard coating for surface enhancement is applied to the lens surface 1a on the object side L1 of the lens 1, and the surface of the lens surface 1a is covered with a thin film 80 of a coating material. The thin film 80 is a hard film such as a UV curable film or a thermosetting film. In forming the thin film 80, a known material can be appropriately used as the coating material to be used according to the target performance. For example, in the case of a UV cured film, either an organic material or an inorganic material may be used, or a hybrid coating material including an organic material and an inorganic material may be used.

Note that the thin film 80 covering the lens surface 1a can have various functions. For example, the UV cured film may have not only a surface strengthening function but also weather resistance. The thin film 80 may be a thin film having an optical function such as an antireflection film or a thin film having a water repellent prevention function. Or what laminated | stacked several types of thin film may be used.

The lens surface 1a can be coated by various methods such as a spin coating method, a dip coating method, and a coating method. For example, in this embodiment, the UV cured film is formed by a spin coating method. If a necessary film thickness (for example, 2 to 3 μm) can be ensured, the coating may be performed by a sputtering method.

Here, in the present embodiment, the coating process on the lens surface 1 a is performed in a state where the lens 1 is caulked and fixed to the holder 7. That is, after assembling the lenses 1 to 4 and the diaphragm 5 into the holder 7, the lens unit 100 after completion of the assembling is held by the spin coater. Then, a coating material is supplied to the tip of the lens unit 100 on the object side L1, and the coating material is uniformly spread on the lens surface 1a by centrifugal force. Thereafter, the coating material is cured by ultraviolet rays, heat, or the like. At this time, the liquid coating material spreads and cures not only to the lens surface 1a but also to the surface of the crimping portion 76 surrounding the outer periphery of the lens surface 1a. As described above, when coating is performed after the lens is assembled to the holder 7, the range in which the coating is performed is a range including not only the lens surface 1 a but also the surface of the front end portion of the holder 7 surrounding the lens 1.

In the lens unit 100, at the portion where the coating material extends to the surface of the crimping portion 76, the lens surface 1a and the surface of the crimping portion 76 are continuously coated. Thereby, the surface of the lens surface 1a and the caulking portion 76 is covered with the continuous thin film 80, and the gap between the lens surface 1a and the caulking portion 76 is sealed. Further, when there is a gap between the lens surface 1a and the crimping portion 76, the liquid coating material penetrates into the gap and hardens, so that the gap between the lens 1 and the inner surface 740 of the large diameter portion 74 is coated. Sealed with material. At this time, the fixing of the lens 1 to the holder 7 is also reinforced by the coating material.

Inside the holder 7, the connecting portion between the inner surface 740 of the large diameter portion 74 and the stepped portion 75 is a liquid reservoir portion 81 where the coating material that has entered the gap between the holder 7 and the lens 1 is accumulated. The coating material that has entered the liquid reservoir 81 seals the gap between the holder 7 and the lens 1 and cures to strengthen the fixation of the lens 1.

Further, at the front end of the holder 7, a step corresponding to the thickness of the front end of the caulking portion 76 is formed at the boundary between the lens surface 1 a and the front end of the caulking portion 76. This level difference is a liquid reservoir 82 where the coating material is accumulated. Here, the tip of the caulking portion 76 is positioned on the outer peripheral side with respect to the lens effective diameter of the lens surface 1a, and a liquid reservoir portion 82 is formed on the outer peripheral side with respect to the lens effective diameter. The coating material supplied to the lens surface 1a is spread so as to have a uniform film thickness within the range of the lens effective diameter of the lens surface 1a. The excess coating material is accumulated in the liquid reservoir 82 and spreads to the surface of the caulking portion 76 on the outer peripheral side by centrifugal force or the like.

A stepped portion 79 having a stepped surface facing the object side L1 is formed on the outer peripheral surface of the large diameter portion 74 on the outside of the holder 7. The stepped portion 79 is formed in an annular shape over the entire circumference of the large diameter portion 74. Of the coating material supplied to the tip of the object side L1 of the lens unit 100, when an excessive coating material flows from the caulking portion 76 to the outer peripheral surface of the large diameter portion 74, the step portion 79 is a liquid pool of the coating material. Part 83. That is, the coating material is prevented from dripping over a wide range along the outer peripheral surface of the holder 7.

(Main effects of this form)
As described above, in the lens unit 100 of the present embodiment, the lens surface 1a of the lens 1 protrudes from the holder 7 to the object side L1 in the apparatus optical axis L direction, and the lens surface 1a exposed to the outside and the lens A continuous coating is applied to the surface of the front end portion (caulking portion 76) of the holder 7 surrounding the surface 1a. In such a configuration, since the thin film 80 that covers the gap between the lens surface 1a and the holder 7 is formed, the gap between the lens 1 and the holder 7 is sealed. Accordingly, the air tightness of the lens unit 100 is enhanced, and it is possible to suppress foreign matters and moisture from entering the lens unit 100. Further, since the coating material is cured, the fixing of the lens 1 to the holder 7 can be strengthened, and the loosening of the lens 1 can be suppressed. Therefore, it is possible to suppress a decrease in the optical performance of the lens unit 100.

In particular, in this embodiment, since the lens surface 1a protrudes from the holder 7, it can be easily applied to a necessary range by various coating methods. For example, the lens surface 1a and the caulking portion 76 can be coated by a simple method such as dip coating. In addition, since the coating is performed after the lenses 1 to 4 and the like are assembled in the holder 7, it is only necessary to perform the coating on non-defective products that have passed the inspection after the completion of the assembly. Therefore, the work load of the coating can be reduced and the coating material can be saved. Further, the surface of the holder 7 can be protected by the coating material, and the holder 7 can be provided with a water repellent function, a surface strengthening function, and the like.

Further, in this embodiment, since the lens 1 is caulked and fixed to the holder 7, the fixing strength of the lens is high. Further, since the liquid reservoir portion 82 is provided at the boundary portion between the crimping portion 76 and the lens surface 1a, the boundary portion where there is a possibility of forming a gap is thickly coated, so that the clearance between the crimping portion 76 and the lens 1 is more reliably provided. Can be sealed. Here, since the liquid reservoir 82 is provided on the outer peripheral side of the lens effective diameter of the lens surface 1a, the coating material accumulated in the liquid reservoir 82 does not affect the optical performance of the lens unit 100. Further, since the caulking portion 76 is provided on the entire circumference of the lens 1, the entire circumference of the lens 1 can be caulked and fixed, and the fixing strength is high. Further, since the liquid reservoir portion 82 is formed on the entire circumference of the lens 1, the lens 1 can be sealed more reliably. The caulking portion 76 may not be provided on the entire circumference of the lens 1. Further, the coating covering the boundary between the caulking portion 76 and the lens surface 1a may not be applied to the entire circumference of the lens surface 1a but may be applied only to a part thereof. Even if it is a part, the effect of improving airtightness and the effect of improving the fixing strength of the lens 1 can be obtained.

Furthermore, in this embodiment, a step portion 75 (positioning portion) for positioning the lens 1 by contacting the lens 1 in the direction of the optical axis L of the lens 1 is formed in the holder 7. The outer peripheral portion of the lens 1 is caulked and fixed between 75 and 75. In such a configuration, the stepped portion 75 becomes the liquid reservoir portion 81 of the coating material, and even if the coating material enters the holder 7 through the gap between the lens 1 and the caulking portion 76, the back side of the liquid reservoir portion 81 ( Intrusion of the coating material into the lens unit) is suppressed. Accordingly, it is possible to suppress the coating material that has entered the gap between the holder 7 and the lens 1 from adhering to the lens surface 1b of the lens 1 and the lenses 2 to 4, and the coating material that has entered the holder 7 is less likely to cause problems. . In addition, the gap between the inner surface 740 of the large-diameter portion 74 and the first lens is sealed by the coating material that accumulates in the liquid reservoir portion 81, and airtightness can be further improved. Further, the fixing strength of the lens 1 can be further increased by the curing of the coating material that has entered the liquid reservoir 81.

In addition, in this embodiment, a stepped portion 79 is also formed on the outer peripheral surface of the holder 7, and this stepped portion 79 becomes a liquid pool portion 83, and the coating material droops over a wide range along the outer peripheral surface of the holder 7. Can be prevented. Therefore, it is possible to suppress problems caused by unnecessary adhesion of the coating material to the outer peripheral surface of the holder.

Further, in this embodiment, since the gap between the lens 1 and the holder 7 is sealed using two kinds of sealing materials, that is, a coating material and an O-ring 78, an effect of improving the air tightness by the O-ring 78 can be obtained. It has a highly airtight structure. The O-ring 78 may be omitted. As a result of performing an airtightness inspection (leakage inspection) with respect to the lens unit 100 when the O-ring 78 is omitted and when the O-ring 78 is present, it is confirmed that even if the O-ring 78 is not provided, an airtightness at an inspection pass level is obtained. I have confirmed.

(Optical unit)
4A and 4B are explanatory diagrams of the optical unit according to the embodiment of the present invention. FIG. 4A is a cross-sectional view of the main part of the optical unit, and FIG. 4B is a partially enlarged cross-sectional view of the optical unit (FIG. 4). It is an enlarged view of the area | region B of (a). The optical unit 200 includes the lens unit 100 having the above-described configuration, a device case 201 as a holding member that holds the lens unit 100, an imaging element (not shown) disposed on the image side L2 of the lens unit 100, and the like.

In the apparatus case 201, a cylindrical holding frame 202 is formed at one end in the apparatus optical axis L direction. The holding frame 202 is formed so as to surround the end of the holder 7 on the side to which the lens 1 is fixed. In the lens unit 100, the outer peripheral surfaces of the flange portion 73 and the large diameter portion 74 are positioned and positioned on the inner side of the holding frame 202 with reference to the inner surface 203 of the holding frame 202. The lens unit 100 is fixed to the device case 201 by an adhesive or press fitting. Other fixing methods may be used. The lens unit 100 is disposed such that the tip portion on the object side L1 (that is, the tip portion of the lens surface 1a and the caulking portion 76) protrudes from the holding frame 202.

In the optical unit 200, the lens surface 1a is hard-coated for surface enhancement as described above, and the surface of the lens surface 1a is covered with a thin film 80 of a coating material. In this embodiment, the lens surface 1 a of the lens unit 100 is coated in a state where the lens unit 100 is fixed to the device case 201. For this reason, as shown in FIG. 4B, coating is continuously applied from the surface of the caulking portion 76 surrounding the lens surface 1 a and the outer periphery thereof to the surface of the holding frame 202 surrounding the outer periphery of the caulking portion 76. .

In such a configuration, the thin film 80 is formed so as to cover not only the gap between the lens surface 1 a and the holder 7 in the lens unit 100 but also the gap between the lens unit 100 and the apparatus case 201, and the lens unit 100 and the apparatus case 201. And the gap is sealed. Accordingly, the air tightness of the optical unit 200 is enhanced, and it is possible to suppress the entry of foreign matter and moisture into the optical unit 200. Moreover, since the coating material is cured, the fixing of the lens unit 100 to the device case 201 can be strengthened, and the loosening of the lens unit 100 can be suppressed. Further, since the tip portion of the lens unit 100 protrudes from the device case 201, coating is easy. Furthermore, the surface of the device case 201 can be protected by a coating material.

In the optical unit 200, as in the lens unit 100, by forming a liquid reservoir at the boundary between the caulking portion 76 and the holding frame 202, the boundary where there is a possibility of forming a gap is thickly coated, and the air tighter. Increases nature. Further, the step portion 79 formed on the outer peripheral surface of the holder 7 in the lens unit 100 functions as a liquid reservoir portion in which the coating material that has entered the gap between the lens unit 100 and the apparatus case 201 is accumulated. Therefore, it is possible to suppress problems caused by the coating material that has entered the optical unit 200. Further, an O-ring may be disposed between the outer peripheral surface of the holder 7 and the inner surface of the apparatus case 201. In this case, the airtightness can be further improved.

Claims

A plurality of lenses arranged along the optical axis;
A cylindrical lens holder for holding the plurality of lenses,
The plurality of lenses includes a first lens on which a convex lens surface is formed,
The first lens is fixed to the lens holder in a state in which at least a part of the lens surface protrudes from one end of the lens holder in the optical axis direction,
A lens unit comprising a continuous coating on at least a part of the lens surface and the surface of the lens holder surrounding the lens surface.
In claim 1,
The lens holder is provided with a caulking portion for caulking and fixing an outer peripheral portion of the first lens,
The lens unit is characterized in that the coating is continuously applied to at least a part of the lens surface and the surface of the lens holder including the surface of the caulking portion.
In claim 2,
The lens unit, wherein a boundary portion between the caulking portion and the lens surface is a liquid reservoir portion in which a coating material is accumulated.
In claim 3,
The lens unit, wherein the caulking portion is provided on the entire circumference of the first lens.
In claim 3 or 4,
The lens unit, wherein the lens surface and the caulking portion are formed such that an outer peripheral side of the lens surface is an effective diameter of the liquid reservoir.
In any one of claims 2 to 5,
On the inner surface of the lens holder, a positioning portion is formed in which the first lens abuts in the optical axis direction.
The lens unit, wherein the caulking portion caulks and fixes the outer peripheral portion of the first lens between the positioning portion and the caulking portion.
In any one of claims 1 to 6,
A lens unit comprising an O-ring disposed between the first lens and the lens holder.
In any one of claims 1 to 7,
A lens unit, wherein a step portion is formed on an outer peripheral surface of the lens holder.
The lens unit according to any one of claims 1 to 8,
A holding member for holding the lens unit;
The holding member includes a holding frame that surrounds an end of the lens holder on the side on which the first lens is fixed,
The optical unit, wherein the coating applied to the lens surface and the surface of the lens holder in the lens unit is continuously applied to at least a part of the surface of the holding frame.