CN110133817B

CN110133817B - Optical unit

Info

Publication number: CN110133817B
Application number: CN201910104137.4A
Authority: CN
Inventors: 新谷昌之; 船桥章; 本目成男
Original assignee: Konica Minolta Inc
Current assignee: Konica Minolta Inc
Priority date: 2018-02-02
Filing date: 2019-02-01
Publication date: 2022-05-31
Anticipated expiration: 2039-02-01
Also published as: JP2019133093A; JP7011220B2; CN110133817A

Abstract

The invention provides an optical unit which does not apply excessive stress to a lens frame and a lens holder even when temperature changes occur in a high-temperature environment and can prevent deterioration of optical performance. An optical unit (100) is provided with: a fourth lens (first optical lens) (L4) having a glass lens body (31) and a resin lens frame (32) with the lens body (31) assembled inside; and a third lens (second optical lens) (L3) having a linear expansion coefficient greater than that of the lens frame (32), wherein the lens frame (32) has a first outward fitting section (4a), the third lens (second optical lens) (L3) has a first inward fitting section (3b), and the third lens (second optical lens) (L3) is fixed to the lens frame (32) by fitting the first outward fitting section (4a) to the first inward fitting section (3 b).

Description

Optical unit

Technical Field

The present invention relates to an optical unit including a lens as an element, the lens holding a glass lens body by a lens frame made of resin.

Background

In applications such as in-vehicle cameras, a glass material is sometimes used for a lens near a diaphragm having high sensitivity in order to maintain optical performance even in an environmental test involving a large temperature change. When a glass lens is used, the outer diameter may not be increased due to processing constraints, and patent document 1 adopts a structure in which a glass lens is housed in a lens frame separate from a lens holder member, and the lens frame is press-fitted into the lens holder member.

However, in the case of this structure, it is preferable that the relationship between the linear expansion coefficients of the lens frame and the lens holder is a relationship in which the linear expansion coefficient of the lens frame is larger than the linear expansion coefficient of the lens holder, and when the lens holder is placed in a high-temperature environment, the lens frame disposed inside expands more than the lens holder, and an excessive stress acts on the lens holder, and an annealing effect is generated in this state. Even when the press-fit relationship is not maintained and a shake occurs between the lens frame and the lens holder, the optical performance may be deteriorated. In addition, it is also conceivable that the lens frame does not have a constant amount of play in the original press-fitting relationship, but in this case, the lens frame may be misaligned with respect to the lens holder at normal temperature, and it is difficult to maintain stable optical performance.

Patent document 1: japanese patent laid-open No. 2014-170123

Disclosure of Invention

The present invention has been made in view of the above-described problems of the background art, and an object of the present invention is to provide an optical unit capable of preventing deterioration of optical performance without applying excessive stress to a lens frame and a lens holder even when a temperature change occurs in a high-temperature environment.

In order to achieve at least one of the above objects, an optical unit reflecting an aspect of the present invention includes: a first optical lens having a glass lens body and a resin lens frame in which the lens body is assembled; and a second optical lens having a linear expansion coefficient larger than that of the lens frame, the lens frame having a first outwardly-fitting portion, the second optical lens having a first inwardly-fitting portion, the second optical lens being fixed to the lens frame by fitting the first outwardly-fitting portion and the first inwardly-fitting portion.

According to the optical unit, since the coefficient of linear expansion of the second optical lens is larger than the coefficient of linear expansion of the lens frame and the second optical lens is fixed to the lens frame by fitting the first outward fitting portion and the first inward fitting portion, the second optical lens expands more than the lens frame when placed in a high-temperature environment, and thus the second optical lens is in a direction in which the fitting is loosened, and it is possible to avoid excessive stress from acting on the frame portion or the lens frame of the second optical lens. Since excessive stress does not act in a high-temperature environment, the fixed state by fitting can be secured when the temperature returns from the high-temperature environment to a normal-temperature environment, and deterioration of optical performance can be prevented. On the other hand, in a low-temperature environment, a phenomenon opposite to the above occurs, and the second optical lens fastens the lens frame and applies a large stress to the lens frame, but since the annealing effect does not occur in the low-temperature environment, the fixing state by fitting of the second optical lens and the lens frame does not change when returning to the normal-temperature environment.

In a specific aspect of the present invention, the optical unit further includes: and a third optical lens having a linear expansion coefficient larger than that of the lens frame, the lens frame having a second outward fitting portion different from the first outward fitting portion, the third optical lens having a second inward fitting portion, and the third optical lens and the lens frame being fixed such that the third optical lens is disposed on the opposite side of the second optical lens with respect to the first optical lens by fitting the second outward fitting portion and the second inward fitting portion. In this case, since the third optical lens and the lens frame are fixed by fitting the second outward fitting portion having a relatively small coefficient of linear expansion and the second inward fitting portion having a relatively large coefficient of linear expansion, excessive stress does not act on the third optical lens or the lens frame in a high-temperature environment depending on the difference in the degree of expansion, and deterioration of the fixed state due to deformation of the frame portion of the third optical lens or the like can be prevented.

In another aspect of the present invention, the present invention further includes: one or more element optical lenses different from the first optical lens and the second optical lens; and a lens holder that holds the first optical lens, the second optical lens, and the element optical lens. In this case, the environmental resistance can be improved by configuring the optical unit with three or more optical lenses and disposing the first optical lens at a position susceptible to the temperature change.

In still another aspect of the present invention, the lens holder fixes any one of the first optical lens, the second optical lens, and the element optical lens at a predetermined position by fitting. In this case, if the relative arrangement of the other optical lenses is adjusted with reference to the optical lens fixed to the lens holder, a predetermined accuracy can be secured with respect to the overall arrangement relationship.

In still another aspect of the present invention, a pair of adjacent optical lenses other than the first optical lens is fixed by the inward fitting portion having a large coefficient of linear expansion and the outward fitting portion having a small coefficient of linear expansion.

In still another aspect of the present invention, the lens frame is formed of a material containing fibers, and the lens body, the second optical lens, and the element optical lens are formed of a material containing no fibers. In this case, the coefficient of linear expansion of the lens frame can be easily made smaller than that of the second optical lens or the like.

In still another aspect of the present invention, the first optical lens is disposed in the vicinity of the stop position. Since the first optical lens has a glass lens body and can suppress the variation in characteristics due to temperature, the temperature sensitivity of the entire optical unit can be reduced by disposing the first optical lens particularly near the stop position.

Drawings

Fig. 1 is a cross-sectional view illustrating an imaging apparatus including an optical unit according to a first embodiment.

Fig. 2A is a partially enlarged cross-sectional view illustrating fixation by fitting of the outer peripheral frame portions of the third lens and the fourth lens, fig. 2B is a partially enlarged cross-sectional view illustrating fixation by fitting of the outer peripheral frame portions of the fourth lens and the fifth lens, and fig. 2C is a partially enlarged cross-sectional view illustrating fixation by fitting of the outer peripheral frame portion of the seventh lens and the image side end portion of the lens holder.

Fig. 3 is a cross-sectional view illustrating an optical unit according to a second embodiment.

Fig. 4 is a cross-sectional view illustrating an optical unit according to a third embodiment.

Detailed Description

[ first embodiment ]

Hereinafter, an optical unit and an imaging device including the same according to a first embodiment of the present invention will be described with reference to the drawings.

As shown in fig. 1, the optical unit 100 is combined with the sensor unit 50 to form an imaging device 200. The optical unit 100 includes an imaging optical system 10 and a lens holder 20 that houses the imaging optical system 10. The photographing optical system 10 is configured by first to seventh lenses L1 to L7. Of the first to seventh lenses L1 to L7, the first to third lenses L1 to L3 and the fifth to seventh lenses L5 to L7 are resin optical lenses, and the fourth lens L4 is an optical lens having a glass lens body 31 and a resin lens frame 32 in which the lens body 31 is incorporated. The lens holder 20 is formed of a resin material, a material obtained by mixing glass fibers in a resin, or the like. A diaphragm ST1 is disposed between the second lens L2 and the third lens L3, and a diaphragm ST2 is fixed to the lens frame 32 of the fourth lens L4. As the lens holder 20 and the lens frame 32, for example, a material in which glass fiber is mixed with polycarbonate or polyamide is used. On the other hand, materials having a refractive index and the like that exhibit desired optical properties are selected for the lenses L1 to L3, L5 to L7, and the lens body 31.

The first lens L1 has a step portion 11c on the image side of the outer peripheral portion 11a, the step portion 11c has a surface parallel to the optical axis AX and a surface perpendicular to the optical axis AX, and the waterproof O-ring 25 is attached to the step portion 11 c. A flat portion 11d having a contact surface perpendicular to the optical axis AX is provided on the image side of the outer peripheral portion 11 a. On the other hand, the object-side outer edge of outer peripheral portion 11a is fixed to object-side end 20a in close contact with a heat caulking portion 20h formed at object-side end 20a of lens holder 20. The second lens L2 has an annular frame 12 outside the main body portion that functions optically, and in the frame 12, the object side contact portion 2a is provided on the first lens L1 side, and the outward fitting portion 2b is provided on the third lens L3 side. The third lens L3 has an annular frame portion 13 outside the main body portion that functions optically, and the frame portion 13 is provided with an inward fitting portion 3a on the second lens L2 side and an inward fitting portion 3b (first inward fitting portion) on the fourth lens L4 side. In the frame portion 14 of the lens frame 32 constituting the fourth lens L4, an outward fitting portion 4a (first outward fitting portion) is provided on the third lens L3 side, and an outward fitting portion 4b (second outward fitting portion) is provided on the fifth lens L5 side. The fifth lens L5 has an annular frame portion 15 outside a main body portion that performs an optical function, and the frame portion 15 is provided with an inward fitting portion 5a (second inward fitting portion) on the fourth lens L4 side and an outward fitting portion 5b on the sixth lens L6 side. The sixth lens L6 has an annular frame portion 16 outside the main body portion that functions optically, and the frame portion 16 is provided with an inward fitting portion 6a on the fifth lens L5 side and an outward fitting portion 6b on the seventh lens L7 side. The seventh lens L7 has an annular frame 17 outside the main body portion that functions optically, and the frame 17 is provided with an inward fitting portion 7a on the sixth lens L6 side and an inward fitting portion 7b on the image side end 20b side of the lens holder 20.

Fig. 2A is a diagram illustrating fixation by fitting of the third lens L3 and the fourth lens L4. The outward fitting portion 4a of the fourth lens L4, which is provided on the third lens L3 side, has an outer peripheral surface 41 parallel to the optical axis AX and a pair of

flat surfaces

42 and 43 perpendicular to the optical axis AX. The inward fitting portion 3b of the third lens L3, which is provided on the fourth lens L4 side, has an inner peripheral surface 44 parallel to the optical axis AX and a pair of

flat surfaces

45 and 46 perpendicular to the optical axis AX. The outer peripheral surface 41 of the outward fitting portion 4a and the inner peripheral surface 44 of the inward fitting portion 3b abut against each other, whereby the third lens L3 and the fourth lens L4 are aligned in a direction perpendicular to the optical axis AX and are supported by each other. Further, the one flat surface 42 of the outward fitting portion 4a and the one flat surface 45 of the inward fitting portion 3b abut against each other, whereby the third lens L3 and the fourth lens L4 are aligned in a direction parallel to the optical axis AX and are supported by each other. In other words, the combination of the outward fitting portion 4a of the lens frame 32 constituting the fourth lens L4 as the first optical lens and the inward fitting portion 3b of the third lens L3 as the second optical lens causes the third and fourth lenses L3 and L4 to be aligned with and fixed to each other in the direction of the optical axis AX and in the direction perpendicular thereto. Here, the

flat surfaces

43 and 46 do not contribute to alignment, and may have any shape that does not interfere with each other, without being limited to the illustrated configuration.

In the third and fourth lenses L3 and L4, materials are selected so that the linear expansion coefficient of the third lens L3 as the second optical lens is larger than the linear expansion coefficient of the lens frame 32 of the fourth lens L4 as the first optical lens, and when the optical unit 100 is placed in a high-temperature environment, the third lens L3 as the second optical lens expands more than the lens frame 32 of the fourth lens L4, and therefore, the fitting is in a loosening direction, and it is possible to avoid an excessive stress from being applied to the frame portion 13 of the third lens L3 and the lens frame 32. Since excessive stress does not act in a high-temperature environment, when the temperature is returned from the high-temperature environment to a normal-temperature environment, the fixed state by the fitting of the inward fitting portion 3b and the outward fitting portion 4a can be ensured, and deterioration of the optical performance of the optical unit 100 can be prevented. On the other hand, in a low-temperature environment, a phenomenon opposite to the above occurs, and the third lens L3 as the second optical lens fastens the lens frame 32 and applies a large stress to the lens frame 32, but since the annealing effect does not occur in the low-temperature environment, the fixed state by the fitting of the third lens L3 and the lens frame 32 does not change when returning to the normal-temperature environment.

Fig. 2B is a diagram illustrating fixation by fitting of the fourth lens L4 and the fifth lens L5. The outward fitting portion 4b of the fourth lens L4, which is provided on the fifth lens L5 side, has an outer peripheral surface 141 parallel to the optical axis AX and a pair of

flat surfaces

142, 143 perpendicular to the optical axis AX. The inward fitting portion 5a of the fifth lens L5 provided on the fourth lens L4 side has an inner peripheral surface 144 parallel to the optical axis AX and a pair of

flat surfaces

145 and 146 perpendicular to the optical axis AX. The outer peripheral surface 141 of the outward fitting portion 4b abuts against the inner peripheral surface 144 of the inward fitting portion 5a, whereby the fourth lens L4 and the fifth lens L5 are aligned in a direction perpendicular to the optical axis AX and are supported by each other. Further, the one flat surface 142 of the outward fitting portion 4b abuts against the one flat surface 145 of the inward fitting portion 5a, whereby the fourth lens L4 and the fifth lens L5 are aligned in a direction parallel to the optical axis AX and are supported by each other. In other words, the combination of the outward fitting portion 4b of the lens frame 32 constituting the fourth lens L4 as the first optical lens and the inward fitting portion 5a of the fifth lens L5 as the third optical lens causes the fourth and fifth lenses L4 and L5 to be aligned with and fixed to each other in the direction of the optical axis AX and in the direction perpendicular thereto. Here, the

planes

143 and 146 do not contribute to alignment, and may have any shape that does not interfere with each other, without being limited to the illustrated configuration.

In the fourth and fifth lenses L4 and L5, the material is selected in a large formula such that the linear expansion coefficient of the fifth lens L5 as the third optical lens is larger than the linear expansion coefficient of the lens frame 32 of the fourth lens L4 as the first optical lens, and the deterioration of the fixed state due to the deformation of the lens frame 32 of the fourth lens L4 and the frame portion 15 of the fifth lens L5 can be prevented without applying an excessive stress to the fifth lens L5 and the lens frame 32 in a high-temperature environment depending on the difference in the expansion degree.

Fig. 2C is a diagram illustrating fixation by fitting of the seventh lens L7 to the image-side end 20b of the lens holder 20. The inward fitting portion 7b of the seventh lens L7, which is provided on the image-side end 20b side, has an inner peripheral surface 241 parallel to the optical axis AX and a pair of

planes

242 and 243 perpendicular to the optical axis AX. The outward fitting portion 8a of the image-side end portion 20b on the seventh lens L7 side has an outer peripheral surface 244 parallel to the optical axis AX, and a pair of

flat surfaces

245 and 246 perpendicular to the optical axis AX. The seventh lens L7 is aligned with and supported by the lens holder 20 in a direction perpendicular to the optical axis AX by the inner peripheral surface 241 of the inward fitting portion 7b abutting against the outer peripheral surface 244 of the outward fitting portion 8 a. Further, the one flat surface 242 of the inward fitting portion 7b abuts against the one flat surface 245 of the outward fitting portion 8a, whereby the seventh lens L7 and the lens holder 20 are aligned in a direction parallel to the optical axis AX and are supported by each other. In other words, the seventh lens L7 is aligned and fixed with respect to the lens holder 20 in the direction of the optical axis AX and in the direction perpendicular thereto by the combination of the inward fitting portion 7b of the seventh lens L7 as an element optical lens and the outward fitting portion 8a of the lens holder 20. Here, the

planes

243 and 246 do not contribute to alignment, and may have any shape that does not interfere with each other, without being limited to the illustrated configuration.

As described above, the material of the lens holder 20 is selected so that the coefficient of linear expansion of the lens holder 20 is equal to or greater than the coefficient of linear expansion of the seventh lens L7, which is an elemental optical lens, and excessive stress does not act on the seventh lens L7 and the image-side end 20b in a high-temperature environment depending on the difference in the degree of expansion, and deterioration of the fixed state due to deformation of the frame portion 17 and the image-side end 20b of the seventh lens L7 can be prevented.

Returning to fig. 1, in the fourth lens L4, the lens body 31 is fixed in a state of being fitted into the inward fitting portion 4c of the lens frame 32. The coefficient of linear expansion of the glass lens body 31 is smaller than the coefficient of linear expansion of the resin lens frame 32, and due to the difference in the degrees of expansion, excessive stress does not act between the lens body 31 and the lens frame 32 in a high-temperature environment, and deformation of the lens frame 32 does not occur in a low-temperature environment, and deterioration of the fixed state due to deformation of the lens frame 32 can be prevented.

Although detailed description is omitted, in the fixation by fitting of the second lens L2 and the third lens L3 which are a pair of adjacent element optical lenses, the outward fitting portion 2b of the second lens L2 having the same or relatively small linear expansion coefficient and the inward fitting portion 3a of the third lens L3 having the same or relatively large linear expansion coefficient are fitted and fixed to each other not only in the direction of the optical axis AX and in the direction perpendicular thereto, but also in a high temperature environment, excessive stress does not act between the second lens L2 and the third lens L3 due to the difference in the degree of expansion, and deterioration of the fixed state can be prevented. In the fixation by fitting of the fifth lens L5 and the sixth lens L6, which are a pair of adjacent element optical lenses, the outward fitting portion 5b of the fifth lens L5 having the same or relatively small coefficient of linear expansion is fitted to the inward fitting portion 6a of the sixth lens L6 having the same or relatively large coefficient of linear expansion, and the fixation is performed while aligning and fixing the lens portions in the direction of the optical axis AX and the direction perpendicular thereto, and an excessive stress is not applied between the fifth lens L5 and the sixth lens L6 in a high temperature environment depending on the difference in the degree of expansion, and thus the fixed state can be prevented from being deteriorated. With respect to fixation by fitting of the sixth lens L6 and the seventh lens L7, which are a pair of adjacent element optical lenses, the outward fitting portion 6b of the sixth lens L6 having the same or relatively small coefficient of linear expansion is fitted to the inward fitting portion 7a of the seventh lens L7 having the same or relatively large coefficient of linear expansion, and not only are the lenses aligned and fixed with each other in the direction of the optical axis AX and in the direction perpendicular thereto, but also excessive stress is not applied between the sixth lens L6 and the seventh lens L7 in a high temperature environment depending on the difference in the degree of expansion, and deterioration of the fixed state can be prevented.

As described above, the first to sixth lenses L1 to L6 have linear expansion coefficients equal to or smaller than the linear expansion coefficient of the lens holder 20, and can reliably avoid adverse effects of stress acting between the lenses and the lens holder 20 in a high-temperature environment, but if an appropriate space SP is provided between the body portion 20c of the lens holder 20 and the outer peripheral surfaces of the frame portions 11 to 16 of the lenses L1 to L6, stress deformation due to expansion of the first to sixth lenses L1 to L6 can be avoided.

To explain the assembly of the optical unit 100 simply, the lens holder 20 is prepared, and the seventh lens L7 is inserted into the lens holder 20 and fixed to the image side end 20b using the

fitting portions

8a and 7 b. Next, the sixth lens L6 is inserted into the lens holder 20 and fixed to the seventh lens L7 by the

fitting portions

7a and 6 b. Next, the fifth lens L5 is inserted into the lens holder 20 and fixed to the sixth lens L6 by the

fitting portions

6a and 5 b. Next, the fourth lens L4 is inserted into the lens holder 20 and fixed to the fifth lens L5 by the

fitting portions

5a and 4 b. Next, the third lens L3 is inserted into the lens holder 20 and fixed to the fourth lens L4 by the

fitting portions

4a and 3 b. Next, the second lens L2 is inserted into the lens holder 20 and fixed to the third lens L3 by the

fitting portions

3a and 2 b. Finally, the O-ring 25 is attached to the step portion 11c of the first lens L1, and then inserted into the lens holder 20, and the flat portion 11d of the first lens L1 is brought into contact with the object side contact portion 2a of the second lens L2, and the portion to be swaged at the tip of the lens holder 20 is thermally deformed to form the thermal swaged portion 20h, thereby completing the assembly of the optical unit 100.

In the imaging device 200, the sensor unit 50 includes: a solid-state imaging element 51 that photoelectrically converts an object image formed by the imaging optical system 10 of the optical unit 100; and a sensor holder 53 that holds the solid-state imaging element 51 and the filter 52. The solid-state imaging element 51 is, for example, a CMOS type image sensor.

In the optical unit 100 of the first embodiment described above, since the material is selected so that the linear expansion coefficient of the third lens L3 as the second optical lens is larger than the linear expansion coefficient of the lens frame 32 of the fourth lens L4 as the first optical lens, and the third lens L3 and the lens frame 32 are fixed by fitting the outward fitting portion 4a and the inward fitting portion 3b, the third lens L3 as the second optical lens is more expanded than the lens frame 32 of the fourth lens L4 when the optical unit 100 is placed in a high-temperature environment. Therefore, the fitting between the third lens L3 and the lens frame 32 is relaxed, and excessive stress can be prevented from acting on the frame portion 13 of the third lens L3 and the lens frame 32. Since excessive stress does not act in a high-temperature environment, when the temperature is returned from the high-temperature environment to a normal-temperature environment, the fixed state by the fitting of the inward fitting portion 3b and the outward fitting portion 4a can be ensured, and deterioration of the optical performance of the optical unit 100 can be prevented. On the other hand, in a low-temperature environment, a phenomenon opposite to the above occurs, and the third lens L3 as the second optical lens fastens the lens frame 32 and applies a large stress to the lens frame 32, but since the annealing effect does not occur in the low-temperature environment, the fixed state by the fitting of the third lens L3 and the lens frame 32 does not change when returning to the normal-temperature environment.

[ second embodiment ]

Hereinafter, an optical unit according to a second embodiment will be described. The optical unit of the second embodiment is obtained by modifying the optical unit of the first embodiment, and the details which are not described in particular are the same as those of the first embodiment and the like.

As shown in fig. 3, the optical unit 100 includes an imaging optical system 10 and a lens holder 20 that houses the imaging optical system 10. The photographing optical system 10 is configured by first to seventh lenses L1 to L7.

In this case, the fourth lens L4 is fixed by fitting in the lens holder 20 and is positioned in a direction perpendicular to the optical axis AX. The seventh lens L7 is not fixed in the lens holder 20 by fitting, but is positioned in the direction of the optical axis AX. Specifically, the outer peripheral surface 9b of the lens frame 32 of the fourth lens L4 is abutted against the inner peripheral surface 9a of the lens holder 20, and the lens holder 20 is fixed in the direction perpendicular to the optical axis AX by fitting with the fourth lens L4. The outward fitting portion 8a is omitted from the image side end portion 20b of the lens holder 20, and the inward fitting portion 7b is omitted from the seventh lens L7. Instead, the flat surface 9d of the frame portion 17 of the seventh lens L7 is abutted against the flat surface 9c of the image-side end portion 20b of the lens holder 20, and the lens holder 20 is abutted against the seventh lens L7, whereby support or positioning in the direction of the optical axis AX is achieved. The fixing or positioning of the first to seventh lenses L1 to L7 is the same as that in the first embodiment, and the description thereof is omitted.

[ third embodiment ]

Hereinafter, an optical unit according to a third embodiment will be described. The optical unit of the third embodiment is obtained by modifying the optical unit of the first embodiment, and the details which are not described in particular are the same as those of the first embodiment and the like.

As shown in fig. 4, in the photographing optical system 10 in the optical unit 100, the second lens L2 is fixed by fitting with the object-side end 20a of the lens holder 20. With respect to fixation of the second lens L2 as an element optical lens to the object side end 20a of the lens holder 20, the inward facing fitting portion 12a of the second lens L2 having the same or relatively large coefficient of linear expansion is fitted to the outward facing fitting portion 8b of the object side end 20a of the lens holder 20 having the same or relatively small coefficient of linear expansion. At this time, the inner peripheral surface 341 of the inward fitting portion 12a abuts against the outer peripheral surface 344 of the outward fitting portion 8b, whereby the second lens L2 is aligned with respect to the lens holder 20 in the direction perpendicular to the optical axis AX. Further, although detailed description is omitted, the second lens L2 is also aligned in the direction of the optical axis AX with respect to the lens holder 20 when the inward fitting portion 12a and the outward fitting portion 8b are fitted. In this case, the third to seventh lenses L3 to L7 are positioned and fixed in order from the second lens L2 as a starting point, and the seventh lens L7 is fixed to the image side end 20b of the lens holder 20 by thermal caulking. The first lens L1 is positioned by bringing the flat portion 11d of the first lens L1 into contact with the object-side end 20a of the lens holder 20.

[ others ]

While the optical unit 100 has been described as a specific embodiment, various modifications can be made without limiting the optical unit of the present invention. For example, the number of optical lenses constituting the imaging optical system 10 is not limited to seven, and for example, three or more optical lenses of various positive and negative power combinations may be used. The shape of the lens holder 20 can be appropriately changed according to the application of the imaging optical system and the like.

In the above embodiment, the fourth lens L4 is a compound type lens constituted by the lens main body 31 and the lens frame 32, but one or more other lenses than the fourth lens L4 may be a compound type lens constituted by the lens main body and the lens frame.

Claims

1. An optical unit is provided with:

a first optical lens having a glass lens body and a resin lens frame in which the lens body is assembled;

a second optical lens having a linear expansion coefficient larger than that of the lens frame;

one or more elemental optical lenses different from the first optical lens and the second optical lens; and

a lens holder that holds the first optical lens, the second optical lens, and the element optical lens,

the optical unit is characterized in that it is provided with,

the first optical lens, the second optical lens, and the element optical lens are integrally inserted into the body of the lens holder in a state where a pair of adjacent optical lenses are fitted to each other,

the lens frame has a first outward fitting portion,

the second optical lens has a first inward-fitting portion,

fixing the second optical lens to the lens frame by fitting the first outward fitting portion and the first inward fitting portion,

the lens holder fixes any one of the first optical lens, the second optical lens, and the element optical lens at a predetermined position by fitting.

2. An optical unit according to claim 1,

further comprising a third optical lens having a linear expansion coefficient larger than that of the lens frame,

the lens frame has a second outward fitting portion different from the first outward fitting portion,

the third optical lens has a second inward fitting portion,

the second outward fitting portion and the second inward fitting portion are fitted to each other, whereby the third optical lens and the lens frame are fixed such that the third optical lens is disposed on the opposite side of the second optical lens with the first optical lens interposed therebetween.

3. An optical unit according to claim 1,

the pair of adjacent optical lenses other than the first optical lens is fixed by an inward fitting portion having a large linear expansion coefficient and an outward fitting portion having a small linear expansion coefficient.

4. An optical unit according to claim 2,

5. An optical unit according to any one of claims 1-4,

the lens frame is formed from a material comprising fibers,

the lens body, the second optical lens, and the element optical lens are formed of a material that does not include fibers.

6. An optical unit according to any one of claims 1-4,

the diaphragm is arranged between the first optical lens and the optical lens adjacent to the first optical lens.

7. An optical unit according to claim 5,