WO2018055844A1

WO2018055844A1 - Lens unit

Info

Publication number: WO2018055844A1
Application number: PCT/JP2017/021369
Authority: WO
Inventors: 智成増沢
Original assignee: 富士フイルム株式会社
Priority date: 2016-09-23
Filing date: 2017-06-08
Publication date: 2018-03-29
Also published as: JP2019203907A

Abstract

This lens unit 10 has a cylindrical lens barrel 40 having a receiving part 43, the receiving part 43 being positioned inside the cylinder in a direction orthogonal to the axial direction of the cylinder. A lens retaining ring 20 is positioned inside the cylinder of the lens barrel 40. The lens retaining ring 20 comprises a first annular part 22, a second annular part 24, and a third annular part 26 which are positioned in such a manner that a gap is formed with the inner periphery of the lens barrel 40, and a supported part 23 facing the receiving part 43 in the axial direction of the cylinder. The lens retaining ring 20 is supported within the cylinder of the lens barrel 40 by the close fitting of the supported part 23 and the receiving part 43. A second lens 34, third lens 36 and fourth lens 38 are fitted to the inner periphery of the lens retaining ring 20, and housed inside the lens barrel 40.

Description

Lens unit

This disclosure relates to a lens unit.

The lens unit may be configured to hold the lens in the lens barrel by press-fitting the lens into the lens holding ring and fitting the lens holding ring inside the lens barrel (for example, Japanese Patent Application Laid-Open No. 2014-2014). No. 170123). When the lens is held in the lens barrel via the lens holding ring in this way, the lens is affected by the lens barrel via the lens holding ring. For example, when the lens expands due to heat, if the lens holding ring also expands due to heat, the force from the lens barrel may act on the lens holding ring and the lens, and stress may be generated in the lens to cause distortion. Further, in order to ensure the positional accuracy of the lens, it is necessary to position the lens barrel and the lens holding ring in the optical axis direction.

The present disclosure is based on the above facts, and is capable of suppressing the distortion of the lens accommodated in the lens barrel and easily positioning the lens holding ring and the lens barrel in the optical axis direction. The purpose is to provide.

The lens unit according to the first aspect is cylindrical, and is arranged with a gap between the lens barrel having a receiving portion arranged in a direction intersecting the cylinder axis direction in the cylinder and the inner periphery of the lens barrel. A lens holding ring that is supported in the barrel of the lens barrel in a state where the supported portion and the receiving portion are in close contact with each other. And a lens fitted in the inner periphery of the annular portion of the lens holding ring and accommodated in the lens barrel.

In the lens unit according to the first aspect, the lens holding ring is supported by the lens barrel in a state in which the receiving portion arranged in the direction intersecting the tube axis direction and the supported portion of the lens holding ring are in close contact with each other. The lens holding ring can be easily positioned in the cylinder axis direction with respect to the cylinder. In addition, since there is a gap between the annular portion of the lens holding ring and the inner periphery of the lens barrel, even if the lens fitted to the inner periphery of the annular portion expands due to heat, it is difficult to receive the force from the lens barrel. can do.

In the lens unit according to the second aspect, a gap is formed between the outer peripheral surface of the lens holding ring and the inner peripheral surface of the lens barrel to allow the lens holding ring to move radially outward over the entire optical axis direction. ing.

In the lens unit according to the second aspect, since the lens holding ring can move radially outward over the entire optical axis direction, the influence of the force from the lens barrel due to the thermal expansion of the lens can be further reduced.

In the lens unit according to the third aspect, the lens barrel has a large diameter portion and a small diameter portion having a smaller diameter than the large diameter portion, and the receiving portion is formed by a step between the large diameter portion and the small diameter portion.

In the lens unit according to the third aspect, the receiving portion can be easily formed by forming the large diameter portion and the small diameter portion in the lens barrel and forming the receiving portion by the step between the large diameter portion and the small diameter portion. .

In the lens unit according to the fourth aspect, the annular portion includes a first annular portion disposed on the radially inner side of the large diameter portion, and a second smaller diameter than the first annular portion disposed on the radially inner side of the small diameter portion. The supported part is formed by a step between the first annular part and the second annular part.

In the lens unit according to the fourth aspect, the first annular portion and the second annular portion are formed respectively corresponding to the large diameter portion and the small diameter portion of the lens barrel, and the first annular portion and the second annular portion to which the lens is fitted are formed. By making the step with the part a supported part, the supported part can be easily formed.

In the lens unit according to the fifth aspect, a resin lens is fitted in the annular portion.

Since the thermal expansion coefficient of the resin is relatively large, it is easy to receive a force from the lens barrel when the lens is thermally expanded. In the lens unit according to the fifth aspect, since the outer periphery of the annular portion into which the resin lens is fitted is separated from the inner periphery of the lens barrel, even if the resin lens expands due to heat, It can make it difficult to receive power.

In the lens unit according to the sixth aspect, the lens holding ring has a fitting portion that fits into the inner periphery of the lens barrel.

Since the lens unit according to the sixth aspect has the fitting portion, the holding force of the lens holding ring in the lens barrel can be increased.

The lens unit according to a seventh aspect is the lens unit according to the sixth aspect, wherein the lens barrel has a large diameter portion and a small diameter portion having a smaller diameter than the large diameter portion, and the receiving portion includes the large diameter portion and the small diameter. It is formed by the level difference of the part.

In the lens unit according to the seventh aspect, the receiving portion can be easily formed by forming the large diameter portion and the small diameter portion in the lens barrel and forming the receiving portion by the step between the large diameter portion and the small diameter portion. .

In the lens unit according to the eighth aspect, the annular portion is disposed radially inside the large diameter portion, the fitting portion is disposed radially inside the small diameter portion, and the supported portion is the annular portion and the fitting portion. It is formed by the level | step difference of the outer periphery.

In the lens unit according to the eighth aspect, the annular portion and the fitting portion are formed respectively corresponding to the large diameter portion and the small diameter portion of the lens barrel, and the outer circumferential step between the annular portion and the fitting portion is supported. By using the part, the supported part can be easily formed.

In the lens unit according to the ninth aspect, the fitting portions are formed at both ends of the annular portion in the optical axis direction.

In the lens unit according to the ninth aspect, the annular portion spaced from the inner periphery of the lens barrel is disposed between the fitting portions that fit into the lens barrel, so that the lens can be held in a balanced manner. it can.

In the lens unit according to the tenth aspect, a glass lens is fitted to the inner periphery of the fitting portion, and a resin lens is fitted to the inner periphery of the annular portion.

In the lens unit according to the tenth aspect, a glass lens having a relatively low coefficient of thermal expansion is accommodated in a fitting portion in which movement of the lens holding ring to the outside in the radial direction is restricted by the lens barrel. Therefore, the force received from the lens barrel due to the thermal expansion of the lens can be made relatively small. In addition, since the outer periphery of the annular portion to which the resin lens is fitted is separated from the inner periphery of the lens barrel, even if the resin lens expands due to heat, it is difficult to receive the force from the lens barrel. it can.

In the lens unit according to the eleventh aspect, the lens holding ring is made of a material whose thermal expansion coefficient in the optical axis direction is smaller than the thermal expansion coefficient in the direction orthogonal to the optical axis.

According to the lens unit of the eleventh aspect, the amount of change in the optical axis direction due to thermal expansion can be reduced to reduce the influence on the resolution reduction.

In the lens unit according to the twelfth aspect, the lens holding ring is formed of an inorganic fiber-containing resin.

According to the lens unit of the twelfth aspect, the strength of the lens holding ring can be increased by forming the lens holding ring with the inorganic fiber-containing resin, and the thermal expansion coefficient is made anisotropic by the orientation of the inorganic fibers. You can have it.

In the lens unit according to the thirteenth aspect, the inner periphery of the lens holding ring and the outer periphery of the lens are in contact with each other at three or more locations in the circumferential direction.

According to the lens unit of the thirteenth aspect, since the outer periphery of the lens is in contact with the inner periphery of the lens holding ring at three or more locations in the circumferential direction, it is easy to ensure the positional accuracy of the lens. Further, when the lens is thermally expanded, even if stress is concentrated on the contact portion between the lens and the lens holding ring, it is possible to make it difficult to receive a force from the lens barrel.

In the lens unit according to the fourteenth aspect, the inner peripheral surface of the lens holding ring is polygonal when viewed from the optical axis direction.

According to the lens unit of the fourteenth aspect, since the inner peripheral surface of the lens holding ring is polygonal, the contact between the outer periphery of the lens and the inner periphery of the lens holding ring is a line contact in the optical axis direction. Thereby, compared with the structure of the surface contact which receives the outer periphery of a lens with a curved surface, the resistance at the time of an assembly | attachment reduces and it is easy to assemble | attach a lens. Further, when the lens is thermally expanded, even if stress is concentrated on the contact portion between the lens and the lens holding ring, it is possible to make it difficult to receive a force from the lens barrel.

In the lens unit according to the fifteenth aspect, a plurality of lenses are fitted in the lens holding ring.

According to the lens unit of the fifteenth aspect, the number of parts can be reduced as compared with the case where a lens holding ring is provided for each lens.

In the lens unit according to the sixteenth aspect, the lens barrel is made of metal.

Since the thermal expansion coefficient of metal is relatively small, even if the lens is thermally expanded, it does not expand following the thermal expansion, and a force from the lens barrel is easily applied to the lens. In the lens unit according to the sixteenth aspect, since the outer periphery of the annular portion is separated from the inner periphery of the lens barrel, even if the lens fitted to the inner periphery of the annular portion expands due to heat, the lens is removed from the lens barrel. The force received can be reduced.

The lens unit according to the seventeenth aspect is an in-vehicle or monitoring lens unit.

Although the on-vehicle and monitoring lens units may be exposed to high temperatures, the lens unit according to the seventeenth aspect has the outer periphery of the annular portion spaced from the inner periphery of the lens barrel. Therefore, even if the lens fitted to the inner periphery of the annular portion is exposed to a high temperature and expands due to heat, it is difficult to receive a force from the lens barrel.

According to the lens unit of the present disclosure, it is possible to suppress the distortion of the lens accommodated in the lens barrel and to easily position the lens holding ring and the lens barrel in the optical axis direction.

It is a semi-longitudinal sectional view of the lens unit concerning a 1st embodiment. FIG. 2 is a cross-sectional view of the lens holding ring of the first embodiment taken along line AA in FIG. FIG. 3 is a cross-sectional view of the lens holding ring of the first embodiment taken along line BB in FIG. FIG. 2 is a cross-sectional view taken along the line CC of FIG. 1 of the lens holding ring of the first embodiment. FIG. 6 is a cross-sectional view taken along the line AA in FIG. 1 of a modification of the lens holding ring of the first embodiment. FIG. 6 is a cross-sectional view taken along line BB of FIG. FIG. 6 is a cross-sectional view taken along the line CC of FIG. It is a half longitudinal cross-sectional view of the lens unit which concerns on 2nd Embodiment. FIG. 6 is a cross-sectional view of the lens holding ring according to the second embodiment, taken along the line DD in FIG. 4. It is a half longitudinal cross-sectional view of the lens unit which concerns on 3rd Embodiment. FIG. 9 is a cross-sectional view of the lens holding ring according to the third embodiment, taken along line EE of FIG.

[First embodiment]
Hereinafter, a first embodiment will be described with reference to the drawings. In the drawings, components having the same function are denoted by the same reference numerals, and description thereof will be omitted as appropriate. Moreover, S shown suitably in each figure shows an optical axis, and the direction along the optical axis S is described as an optical axis direction.

As shown in FIG. 1, the lens unit 10 according to this embodiment includes a lens barrel 40, a lens holding ring 20, a cap 16, a spacing ring 14, and a lens group 30. In FIG. 1, the left side in the figure is the object side, and the right side in the figure is the image side. An imaging element (not shown) such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor is disposed on the image side of the lens unit 10. *

<Lens>
The lens group 30 includes a first lens 32, a second lens 34, a third lens 36, and a fourth lens 38, which are arranged in order from the object side.

The first lens 32 is formed in a substantially circular shape when viewed from the optical axis direction, and is curved so as to be convex on the object side. The image side of the first lens 32 is curved so that the center is concave, and a flat portion 32F is formed on the outer edge facing the image side. The first lens 32 has a groove 32A formed on the outer periphery on the image side, and an O-ring 32B is attached to the groove 32A. In the first lens 32, an outer peripheral portion 32C is formed on the outer periphery on the object side of the groove 32A. The first lens 32 is fitted into a large diameter portion 42 of a lens barrel 40 described later. As an example, the first lens 32 is made of glass.

The second lens 34 is formed in a substantially circular shape when viewed from the optical axis direction, the object side is curved so that the center is convex, and a flat portion 34E is formed on the outer edge facing the object side. The flat portion 34E is in contact with the flat portion 32F of the first lens 32. The image side of the second lens 34 is curved so that the center is concave, and a flat portion 34F is formed on the outer edge facing the image side. The second lens 34 has a smaller diameter than the first lens 32, and an outer peripheral portion 34 C is formed on the outer periphery of the second lens 34. The second lens 34 is fitted into the first annular portion 22 of the lens holding ring 20 described later. The second lens 34 is made of resin.

The third lens 36 is formed in a substantially circular shape when viewed from the optical axis direction, the object side is curved so that the center is concave, and a flat portion 36E is formed on the outer edge facing the object side. The flat portion 36E is in contact with the flat portion 34F of the second lens 34. The image side of the third lens 36 is curved so that the center is convex, and a flat portion 36F is formed on the outer edge facing the image side. The flat portion 36F is in contact with an end face 14E of the interval ring 14 described later. The third lens 36 has a smaller diameter than the second lens 34, and an outer peripheral portion 36 C is formed on the outer periphery of the third lens 36. The third lens 36 is fitted into the second annular portion 24 of the lens holding ring 20 described later. The third lens 36 is made of glass.

The fourth lens 38 is formed in a substantially circular shape when viewed from the optical axis direction, the object side is curved so that the center is convex, and a flat portion 38E is formed on the outer edge facing the object side. The flat portion 38E is in contact with a flat portion 14F of the interval ring 14 described later. The image side of the fourth lens 38 is curved so that the center is convex, and a flat portion 38F is formed on the outer edge facing the image side. The fourth lens 38 has a slightly smaller diameter than the third lens 36, and an outer peripheral portion 38 C is formed on the outer periphery of the fourth lens 38. The fourth lens 38 is fitted into a third annular portion 26 of the lens holding ring 20 described later. The fourth lens 38 is made of resin.

<Interval ring>
The spacing ring 14 is an annular member as viewed in the optical axis direction, the object-side end surface 14E is in contact with the flat portion 36F of the third lens 36, and the image-side flat portion 14F is the flat portion 38E of the fourth lens 38. In contact with. The spacing ring 14 determines the spacing in the optical axis direction between the third lens 36 and the fourth lens 38. The spacing ring 14 is made of resin.

<Tube>
As shown in FIG. 1, the lens barrel 40 is formed in a cylindrical shape, and is arranged so that the optical axis S coincides with the cylinder axis. The lens barrel 40 has a large diameter portion 42 disposed on the object side and a small diameter portion 44 disposed on the image side. The inner peripheral surfaces of the large-diameter portion 42 and the small-diameter portion 44 are circular when viewed from the optical axis direction. The image side end of the large diameter portion 42 and the object side end of the small diameter portion 44 are connected by a receiving portion 43. The receiving portion 43 forms a step between the large-diameter portion 42 and the small-diameter portion 44, is disposed in the radial direction so as to be orthogonal to the cylinder axis, and has a flat surface facing the object side. The receiving portion 43 receives a supported portion 23 of the lens holding ring 20 described later in the optical axis direction.

The first lens 32 is fitted to the inner peripheral surface of the object side end of the large diameter portion 42. A space between the first lens 32 and the inner peripheral surface of the large diameter portion 42 is sealed with an O-ring 32B. On the image-side end of the small diameter portion 44, a protruding line 44A protruding from the inner peripheral surface is formed.

A male screw 42 A is formed on the outer periphery of the large-diameter portion 42. A cap 16 described later is screwed onto the male screw 42A.

The lens barrel 40 can be made of metal as an example. Since the thermal expansion coefficient of the metal is relatively small, even if the lens is thermally expanded, it does not expand following the thermal expansion, and the force from the lens barrel 40 is easily applied to the lens. Thus, when the lens barrel 40 is made of metal, it can be suitably used to reduce the force that the lens receives from the lens barrel 40. The lens barrel 40 can also be made of resin using the same material as the lens holding ring 20 described later.

<Cap>
The cap 16 is annular and is disposed on the outer periphery of the large-diameter portion 42 of the lens barrel 40. The cap 16 has a pressing portion 16 B formed at the end on the object side. The pressing portion 16B is configured by a ridge protruding inward in the radial direction. The outer edge of the first lens 32 on the object side is pressed by the pressing portion 16B, and the detachment of the first lens 32 from the lens barrel 40 is restricted.

The outer diameter of the cap 16 is larger than the outer diameter of the lens barrel 40. A female screw 16A is formed on the inner peripheral surface of the cap 16, and is screwed with a male screw 42A formed on the outer periphery of the large-diameter portion 42 of the lens barrel 40. The cap 16 can be formed of metal as an example.

<Lens holding ring>
As shown in FIG. 1, the lens holding ring 20 has a cylindrical shape with both ends in the optical axis direction opened, and is formed by resin molding. The lens holding ring 20 is disposed so that the cylinder axis coincides with the optical axis of the lens unit 10.

Here, as an example, the lens holding ring 20 can be made of a resin containing inorganic fibers. By making the lens holding ring 20 made of a so-called fiber reinforced plastic containing inorganic fibers or the like, the mechanical strength is increased. Examples of the resin used include polyamide, polyacetal, polycarbonate, polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate, polyethylene, syndiotactic polystyrene, polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, polyamideimide, and polyether. It is possible to use at least one selected from the group consisting of imide, polyether ether ketone, acrylonitrile budadiene styrene, polyolefin and each modified polymer, or a polymer alloy containing at least one selected from the group. As the fiber, glass fiber, carbon fiber, fiber reinforced plastic, inorganic filler, or the like can be used.

The lens holding ring 20 preferably has a thermal expansion coefficient in the optical axis direction smaller than the thermal expansion coefficient in the direction orthogonal to the optical axis. This is because the amount of change in the optical axis direction due to thermal expansion can be reduced to reduce the effect on resolution reduction. By making the above-mentioned fiber orientation direction along the optical axis, the thermal expansion coefficient in the optical axis direction can be made smaller than the thermal expansion coefficient in the direction orthogonal to the optical axis.

The lens holding ring 20 has a first annular portion 22, a second annular portion 24, and a third annular portion 26 in order from the object side. The outer diameter of the first annular portion 22 is set smaller than the inner diameter of the large diameter portion 42 of the lens barrel 40 and larger than the inner diameter of the small diameter portion 44. The first annular portion 22 is disposed on the radially inner side of the large diameter portion 42. A flange portion 21 that extends radially outward is formed at the object-side end of the first annular portion 22. A flat surface 21 E is formed on the object side of the flange portion 21. An outer peripheral surface 21 A is formed on the radially outer end surface of the flange portion 21. The flat surface 21E and the flat portion 32F of the first lens 32 are separated from each other. Further, the outer peripheral surface 21A and the inner peripheral surface of the large diameter portion 42 of the lens barrel 40 are separated from each other. An outer peripheral surface 22 A facing outward in the radial direction is formed on the outer periphery on the image side of the flange portion 21 of the first annular portion 22. The outer peripheral surface 22A and the inner peripheral surface of the large diameter portion 42 of the lens barrel 40 are separated from each other.

The outer diameter of the second annular portion 24 is set smaller than the inner diameter of the small diameter portion 44 of the lens barrel 40, and the inner diameter of the second annular portion 24 is set smaller than the inner diameter of the first annular portion 22. A flat portion 24 E is formed on the object-side end surface of the second annular portion 24. On the outer periphery of the second annular portion 24, an outer peripheral surface 24A facing outward in the radial direction is formed. The second annular portion 24 is disposed on the radially inner side of the small diameter portion 44. 24 A of outer peripheral surfaces and the internal peripheral surface of the small diameter part 44 of the lens-barrel 40 are spaced apart.

A supported portion 23 is formed between the image side end portion of the first annular portion 22 and the object side end portion of the second annular portion 24. The supported portion 23 is arranged to extend in the radial direction so as to be orthogonal to the cylinder axis, and is a step toward the image side. The supported portion 23 is in close contact with the receiving portion 43 of the lens barrel 40, and the lens holding ring 20 is held by the lens barrel 40 at the supported portion 23.

The outer diameter of the third annular portion 26 is set smaller than the outer diameter of the second annular portion 24, and the inner diameter of the third annular portion 26 is set smaller than the inner diameter of the second annular portion 24. On the outer periphery of the third annular portion 26, an outer peripheral surface 26A facing outward in the radial direction is formed. The third annular portion 26 is disposed on the radially inner side of the small diameter portion 44. The outer peripheral surface 26A is separated from the inner periphery of the small-diameter portion 44 of the lens barrel 40 and the inner periphery of the protrusion 44A. On the image-side end of the third annular portion 26, a ridge 26D protruding inward in the radial direction is formed.

2A, 2B, and 2C, the inner peripheral surface 22B of the first annular portion 22, the inner peripheral surface 24B of the second annular portion 24, and the inner peripheral surface 26B of the third annular portion 26 are: It is formed in a polygonal shape as viewed from the optical axis direction, and in the present embodiment, as an example, it is formed in a substantially regular dodecagonal shape as viewed from the optical axis direction. Each of the 12 surfaces constituting the inner

peripheral surfaces

22B, 24B, and 26B is a straight flat surface when viewed from the optical axis direction. Each flat surface constituting the inner peripheral surface 22B is defined as a flat surface 22C, each flat surface constituting the inner peripheral surface 24B is defined as a flat surface 24C, and each flat surface constituting the inner peripheral surface 26B is defined as a flat surface 26C. 2A, 2B, and 2C, members other than the lens holding ring 20 and the second lens 34, the second lens 36, and the third lens 38 that are fitted to the inner periphery thereof are omitted. .

A second lens 34 is fitted on the inner periphery of the first annular portion 22. As for the 2nd lens 34, the outer peripheral part 34C is linearly hold | maintained by each of the flat surfaces 22C in the optical axis direction. The flat portion 34F of the second lens 34 and the flat portion 24E of the second annular portion 24 are separated (see FIG. 1).

A third lens 36 is fitted on the inner periphery of the second annular portion 24. The outer periphery 36C of the third lens 36 is linearly held in the optical axis direction by each of the flat surfaces 24C. A spacing ring 14 is fitted to the inner side of the second annular portion 24 on the image side of the third lens 36. The spacing ring 14 has an outer peripheral portion 14C that is linearly held in the optical axis direction by each of the flat surfaces 24C. A fourth lens 38 is fitted on the inner periphery of the third annular portion 26. In the fourth lens, the outer peripheral portion 38C is held linearly in the optical axis direction by each of the flat surfaces 26C.

The entire outer peripheral surface (outer

peripheral surfaces

21A, 22A, 24A, 26A) facing the radially outer side of the lens holding ring 20 is separated from the inner peripheral surface of the lens barrel 40.

(Function and effect)
Next, the operation and effect of this embodiment will be described.

In the lens unit 10 of the present embodiment, the lens holding ring 20 is supported by the lens barrel 40 when the supported portion 23 of the lens holding ring 20 is in close contact with the receiving portion 43 of the lens barrel 40. Therefore, it is possible to easily position the lens holding ring 20 with respect to the lens barrel 40 in the optical axis direction. Further, since the entire outer peripheral surface (the outer

peripheral surfaces

21A, 22A, 24A, 26A) of the lens holding ring 20 is separated from the inner peripheral surface of the lens barrel 40, it is fitted to the inner periphery of the lens holding ring 20. Even if the lenses (the second lens 34, the third lens 36, and the fourth lens 38) expand due to heat, the lens holding ring 20 as a whole can also move radially outward. Therefore, it is possible to make the lens (second lens 34, third lens 36, and fourth lens 38) less susceptible to force from the lens barrel 40.

In the present embodiment, the second lens 34 and the fourth lens 38 are made of resin and have a relatively large coefficient of thermal expansion. Since a gap is formed between the portion 22 and the third annular portion 26 and the inner periphery of the lens barrel 40, the force from the lens barrel 40 can be made difficult to receive.

In the present embodiment, the lens barrel 40 is provided with the large-diameter portion 42 and the small-diameter portion 44, and the receiving portion 43 is configured by the step between the large-diameter portion 42 and the small-diameter portion 44. Can be formed. Further, the lens holding ring 20 is also provided with the first annular portion 22 and the second annular portion 24, and the supported portion 23 is configured by the step between the first annular portion 22 and the second annular portion 24. The supported portion 23 can be easily formed.

Further, the inner peripheral surface (inner

peripheral surfaces

22B, 24B, 26B) of the lens holding ring 20 of the lens unit 10 of the present embodiment is formed in a polygonal shape when viewed from the optical axis direction. Therefore, the contact between the outer periphery of the lens (the outer

peripheral portions

34C, 36C, and 38C) and the inner peripheral surface of the lens holding ring 20 is a line contact in the optical axis direction. Thereby, compared with the structure of the surface contact which receives the outer periphery of a lens with a curved surface, the resistance at the time of an assembly | attachment reduces and it is easy to assemble | attach a lens. Further, when the lenses (second lens 34, third lens 36, and fourth lens 38) fitted to the inner periphery of the lens holding ring 20 are thermally expanded, stress concentrates on the holding position by the lens holding ring 20. However, the force from the lens barrel 40 can be made difficult to receive. Further, since each lens is supported at multiple points of three or more points, it is easy to ensure the positional accuracy of each lens.

Further, since the lens unit 10 of the present embodiment holds a plurality of lenses by the lens holding ring 20, the number of parts can be reduced as compared with the case where the lens holding ring is provided for each lens.

In the present embodiment, the inner peripheral surface 22B of the first annular portion 22, the inner peripheral surface 24B of the second annular portion 24, and the inner peripheral surface 26B of the third annular portion 26 are substantially positive when viewed from the optical axis direction. Although it is formed in a dodecagonal shape, it is not necessarily a regular dodecagonal shape, and may be a regular hexagonal shape, a regular octagonal shape, or a circular shape when viewed from the optical axis direction.

3A, 3B, and 3C, the inner peripheral surface 22B of the first annular portion 22, the inner peripheral surface 24B of the second annular portion 24, and the inner peripheral surface 26B of the third annular portion 26 are provided. In addition, the

lens receiving portions

22G, 24G, and 26G that protrude radially inward may be formed. The lens receiving portions 22G protrude radially inward from three equally spaced locations in the circumferential direction of the inner peripheral surface 22B, and the lens receiving portions 24G radially inward from three equally spaced locations in the circumferential direction of the inner peripheral surface 24B. The lens receiving portion 26G protrudes radially inward from three equally spaced locations in the circumferential direction of the inner peripheral surface 26B. In this case, the second lens 34 is held by the lens receiver 22G, the third lens 36 is held by the lens receiver 24G, and the fourth lens 38 is held by the lens receiver 26G. Even in this case, each lens is supported by multiple points of three or more points, so it is easy to ensure the positional accuracy of each lens. In addition, when the lens is thermally expanded, even if stress is concentrated on the contact portion between the lens and the lens holding ring 20, it is possible to make it difficult to receive the force from the lens barrel 40.

[Second Embodiment]
Next, the lens unit 48 of the second embodiment will be described. In addition, about the structure same as 1st Embodiment, the code | symbol same as 1st Embodiment is attached | subjected and description is abbreviate | omitted. The lens unit 48 of the present embodiment is different from the first embodiment in the configuration of the lens holding ring, and the other configurations are the same as those in the first embodiment.

As shown in FIG. 4, the lens unit 48 of this embodiment includes a lens holding ring 50. The lens holding ring 50 has a cylindrical shape with both ends in the optical axis direction opened, and is formed by resin molding. The lens holding ring 50 is disposed so that the cylinder axis coincides with the optical axis of the lens unit 48. The lens holding ring 50 can be formed of the same material as the lens holding ring 20 of the first embodiment. The lens holding ring 50 preferably has a thermal expansion coefficient in the optical axis direction smaller than the thermal expansion coefficient in the direction orthogonal to the optical axis. This is because the amount of change in the optical axis direction due to thermal expansion can be reduced to reduce the effect on resolution reduction. By making the above-mentioned fiber orientation direction along the optical axis, the thermal expansion coefficient in the optical axis direction can be made smaller than the thermal expansion coefficient in the direction orthogonal to the optical axis.

The lens holding ring 50 has a first annular portion 22 and a third annular portion 26 similar to the lens holding ring 20 of the first embodiment, and has a fitting portion 54 instead of the second annular portion 24. Yes. The outer diameter of the fitting portion 54 is substantially the same as the inner diameter of the small diameter portion 44 of the lens barrel 40, and is set so as to be fitted to the inner periphery of the small diameter portion 44. The inner diameter of the fitting portion 54 is set smaller than the inner diameter of the first annular portion 22. A flat portion 54 E is formed on the object-side end surface of the fitting portion 54. The flat portion 54E is separated from the flat portion 34F of the second lens 34. On the outer periphery of the fitting portion 54, an outer peripheral surface 54A facing outward in the radial direction is formed. The fitting portion 54 is disposed on the radially inner side of the small diameter portion 44. The outer peripheral surface 54 A is in close contact with the inner periphery of the small diameter portion 44 of the lens barrel 40, and the fitting portion 54 is fitted to the small diameter portion 44.

A supported portion 23 is formed between the image side end portion of the first annular portion 22 and the object side end portion of the fitting portion 54. The supported portion 23 is arranged to extend in the radial direction so as to be orthogonal to the cylinder axis, and is a step toward the image side. The supported portion 23 is in close contact with the receiving portion 43 of the lens barrel 40, and the lens holding ring 50 is held by the lens barrel 40 at the supported portion 23.

As shown in FIG. 5, the inner peripheral surface 54B of the fitting portion 54 is formed in a polygonal shape when viewed from the optical axis direction. It is formed into a shape. Each of the 12 surfaces constituting the inner peripheral surface 54B is a straight flat surface as viewed from the optical axis direction. Each flat surface constituting the inner peripheral surface 54B is defined as a flat surface 54C. The third lens 36 is fitted on the inner periphery of the fitting portion 54. The outer periphery 36C of the third lens 36 is held linearly in the optical axis direction by each of the flat surfaces 54C. The spacing ring 14 is fitted to the inner periphery of the fitting portion 54 on the image side of the third lens 36. The spacing ring 14 has an outer peripheral portion 14 C linearly held in the optical axis direction by each of the flat surfaces 54 C.

Outer

peripheral surfaces

21A, 22A, and 26A among the outer peripheral surfaces facing the radially outer side of the lens holding ring 20 are separated from the inner peripheral surface of the lens barrel 40.

In addition, the shape of the inner peripheral surface 54B can be made equivalent to each modification of the first embodiment.

In the lens unit 48 of the present embodiment, the supported portion 23 is in close contact with the receiving portion 43 of the lens barrel 40 and the fitting portion 54 is fitted into the small diameter portion 44 of the lens barrel 40, so that the lens holding ring 50 is formed. It is supported by the lens barrel 40. Therefore, the lens holding ring 50 can be easily positioned in the optical axis direction with respect to the lens barrel 40 and the holding force of the lens holding ring 50 in the lens barrel 40 can be increased.

In the present embodiment, the third lens 36 made of glass is fitted in the inner periphery of the fitting portion 54. Since the thermal expansion coefficient of the glass-made third lens 36 is smaller than that of the resin-made lens, the force received from the lens barrel 40 due to the thermal expansion of the lens can be made relatively small.

In the present embodiment, the lens holding ring 50 is provided with the first annular portion 22 and the fitting portion 54, and the supported portion 23 is configured by a step between the first annular portion 22 and the fitting portion 54. Therefore, the supported portion 23 can be easily formed.

Further, the inner peripheral surface 54B of the fitting portion 54 of the lens holding ring 50 of the lens unit 48 of the present embodiment is formed in a polygonal shape when viewed from the optical axis direction. Therefore, the contact between the outer peripheral portion 36C of the third lens 36 and the inner peripheral surface of the lens holding ring 50 is a line contact in the optical axis direction. Thereby, compared with the structure of the surface contact which receives the outer periphery of a lens with a curved surface, the resistance at the time of an assembly | attachment reduces and it is easy to assemble | attach a lens. Further, when the third lens 36 fitted to the inner periphery of the lens holding ring 50 is thermally expanded, even if stress is concentrated on the holding position by the lens holding ring 50, it is difficult to receive the force from the lens barrel 40. be able to.

Further, since the lens unit 48 of the present embodiment holds a plurality of lenses by the lens holding ring 50, the number of parts can be reduced as compared with the case where the lens holding ring is provided for each lens.

[Third embodiment]
Next, the lens unit 58 of the third embodiment will be described. In addition, about the structure same as 1st, 2nd embodiment, the code | symbol same as 1st, 2nd embodiment is attached | subjected, and description is abbreviate | omitted. The lens unit 58 of this embodiment is different from the second embodiment in the configuration of the image side of the lens barrel and the lens holding ring, and the other configurations are the same as those in the second embodiment.

As shown in FIG. 6, a protrusion 44 A is formed on the image side of the lens barrel 40. The protrusion 44 A extends longer to the image side than the protrusion 44 A of the first embodiment. In the lens holding ring 50, a second fitting portion 56 is formed on the image side of the ridge 26D. The second fitting portion 56 is annular, the outer diameter is larger than the outer diameter of the third annular portion 26, and the inner diameter is smaller than the inner diameter of the third annular portion 26. An outer peripheral portion 56 A is formed on the radially outer side of the second fitting portion 56. The outer peripheral portion 56A is in close contact with the inner periphery of the ridge 44A. The inner peripheral surface 56B of the second fitting portion 56 is formed in a polygonal shape as viewed from the optical axis direction. In the present embodiment, as an example, the inner peripheral surface 56B is formed in a substantially regular dodecagonal shape as viewed from the optical axis direction. . Each of the 12 surfaces constituting the inner peripheral surface 56B is a straight flat surface as viewed from the optical axis direction. Each flat surface constituting the inner peripheral surface 56B is defined as a flat surface 56C.

The fifth lens 39 is fitted to the inner periphery of the second fitting portion 56. The fifth lens 39 is formed in a substantially circular shape when viewed from the optical axis direction, and is curved so that both the object side and the image side are convex. The fifth lens 39 has a smaller diameter than the fourth lens 38, and an outer peripheral portion 39 C is formed on the outer periphery of the fifth lens 39. The outer periphery 39C of the fifth lens 39 is linearly held in the optical axis direction by each of the flat surfaces 56C. The fifth lens 39 is made of glass.

Note that the shape of the inner peripheral surface 56B may be the same as that of each modification of the first embodiment.

In the lens unit 58 of the present embodiment, the same components as in the second embodiment can achieve the same effects as those of the lens unit 48 according to the second embodiment.

In the lens unit 58 of the present embodiment, since the second fitting portion 56 of the lens holding ring 50 is fitted to the protrusion 44A of the lens barrel 40, the holding force of the lens holding ring 50 in the lens barrel 40 is increased. be able to.

Moreover, since the 3rd annular part 26 spaced apart from the inner periphery of the lens-barrel 40 is arrange | positioned between the fitting part 54 fitted to the inner periphery of the lens-barrel 40, and the 2nd fitting part 56, it is in good balance The fourth lens 38 can be held.

In the present embodiment, the fifth lens 39 made of glass is fitted on the inner periphery of the second fitting portion 56. Since the thermal expansion coefficient of the glass-made fifth lens 39 is smaller than that of the resin-made lens, the force received from the lens barrel 40 due to thermal expansion of the lens can be made relatively small.

Further, the inner peripheral surface 56B of the second fitting portion 56 of the lens holding ring 50 of the lens unit 58 of the present embodiment is formed in a polygonal shape when viewed from the optical axis direction. Therefore, the contact between the outer peripheral portion 39C of the fifth lens 39 and the inner peripheral surface of the lens holding ring 50 is a line contact in the optical axis direction. Thereby, compared with the structure of the surface contact which receives the outer periphery of a lens with a curved surface, the resistance at the time of an assembly | attachment reduces and it is easy to assemble | attach a lens. Further, when the fifth lens 39 fitted to the inner periphery of the lens holding ring 50 is thermally expanded, even if stress is concentrated on the holding position by the lens holding ring 50, it is difficult to receive the force from the lens barrel 40. be able to.

In addition, the lens units according to the first to third embodiments can reduce performance deterioration even when used in an environment where it is difficult to maintain imaging performance, such as exposure to high temperatures. Therefore, it is suitable for those that may be exposed to high temperatures, such as surveillance cameras and in-vehicle cameras. The monitoring lens unit is a lens unit that is provided in a building or the like and captures images of surrounding objects. The in-vehicle lens unit is a lens unit that is provided in a vehicle (mainly in a vehicle interior) and captures an image of an object or the like outside the vehicle.

The disclosure of Japanese Patent Application No. 2016-185881 filed on September 23, 2016 is hereby incorporated by reference in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference, Incorporated herein by reference.

10 lens unit 14 spacing ring, 14C outer peripheral part, 14E end face, 14F flat part 16 cap, 16B pressing part,
20 Lens holding ring 21 Flange, 21A Outer peripheral surface, 21E Flat surface,
22 1st annular part (annular part), 22A outer peripheral surface, 22B inner peripheral surface, 22C flat surface 22G lens receiving part 23 supported part 24 2nd annular part (annular part), 24A outer peripheral surface, 24B inner peripheral surface, 24C Flat surface 24E Flat portion, 24G Lens receiving portion 26 Third annular portion (annular portion), 26A Outer peripheral surface, 26B Inner peripheral surface, 26C Flat surface 26D Convex, 26G Lens receiving portion 30 Lens group 32 First lens, 32A Groove , 32B O-ring, 32C outer peripheral portion 32F flat portion 34 second lens (lens, resin lens), 34C outer peripheral portion 34E, 34F flat portion 36 third lens (glass lens), 36C outer peripheral portion 36E, 36F flat portion 38 Fourth lens (lens, resin lens), 38C outer peripheral portion 38E, 38F flat portion 39 fifth lens (glass lens), 39C outer peripheral portion 40 lens barrel, 42 large-diameter portion, 43 receiving portion, 44 small-diameter portion, 44A convex ridge 48 lens unit 50 lens holding ring 54 fitting portion, 54A outer peripheral surface, 54B inner peripheral surface, 54C flat surface 54E flat portion 56 second fitting portion ( Fitting portion), 56A outer peripheral surface, 56B inner peripheral surface, 56C flat surface 58 lens unit S optical axis

Claims

A lens barrel having a receiving portion arranged in a direction intersecting the cylinder axis direction in a cylinder
An annular annular portion disposed with a gap between the inner periphery of the lens barrel and a supported portion that faces the receiving portion in the tube axis direction, and the supported portion and the receiving portion A lens holding ring supported in the barrel of the lens barrel in a state in which the portion is in close contact,
A lens fitted in the inner periphery of the annular portion of the lens holding ring and accommodated in the lens barrel;
Lens unit equipped with.
2. A gap is formed between the outer peripheral surface of the lens holding ring and the inner peripheral surface of the lens barrel to allow the lens holding ring to move radially outward over the entire optical axis direction. The lens unit described in 1.
The lens barrel has a large-diameter portion and a small-diameter portion having a smaller diameter than the large-diameter portion, and the receiving portion is formed by a step between the large-diameter portion and the small-diameter portion. The lens unit described.
The annular portion includes a first annular portion disposed on the radially inner side of the large diameter portion and a second annular portion having a smaller diameter than the first annular portion disposed on the radially inner side of the small diameter portion. The lens unit according to claim 3, wherein the supported portion is formed by a step between the first annular portion and the second annular portion.
The lens unit according to any one of claims 1 to 4, wherein a resin lens is fitted into the annular portion.
The lens unit according to claim 1, wherein the lens holding ring has a fitting portion that fits into an inner periphery of the lens barrel.
The lens barrel has a large diameter portion and a small diameter portion smaller in diameter than the large diameter portion, and the receiving portion is formed by a step between the large diameter portion and the small diameter portion. The lens unit described.
The annular portion is disposed radially inside the large diameter portion, the fitting portion is disposed radially inside the small diameter portion, and the supported portion is a step between the annular portion and the fitting portion. The lens unit according to claim 7, formed by:
The lens unit according to claim 6 or 7, wherein the fitting portion is formed at both ends of the annular portion in the optical axis direction.
The glass lens according to any one of claims 6 to 9, wherein a glass lens is fitted to the inner periphery of the fitting portion, and a resin lens is fitted to the inner periphery of the annular portion. Lens unit.
The lens according to any one of claims 1 to 10, wherein the lens holding ring is made of a material whose thermal expansion coefficient in the optical axis direction is smaller than the thermal expansion coefficient in the direction orthogonal to the optical axis. unit.
12. The lens unit according to claim 1, wherein the lens holding ring is made of an inorganic fiber-containing resin.
The lens unit according to any one of claims 1 to 12, wherein an inner periphery of the lens holding ring and an outer periphery of the lens are in contact with each other at three or more locations in the circumferential direction.
The lens unit according to any one of claims 1 to 13, wherein an inner peripheral surface of the lens holding ring has a polygonal shape when viewed from the optical axis direction.
The lens unit according to any one of claims 1 to 14, wherein a plurality of the lenses are fitted into the lens holding ring.
The lens unit according to any one of claims 1 to 15, wherein the lens barrel is made of metal.
The lens unit according to any one of claims 1 to 16, wherein the lens unit is for vehicle use or for monitoring.