JP2020154121A - Lens unit - Google Patents

Abstract

To highly accurately determine positional relations between individual lenses and between the lenses and a diaphragm.SOLUTION: A fifth lens L5 is made of glass, and is housed in a lens barrel while being press-fitted in a lens holder 51 made of a resin material to form an integrated fifth lens body L50. On an object side of the lens holder 51, three convex parts 51A, in each of which a cross-sectional shape vertical to an optical axis A is round, are formed at regular intervals in a circumferential direction. The periphery of the convex parts 51A is regarded as a diaphragm placing surface 51B vertical to the optical axis A. Meanwhile, on a diaphragm 20, three positioning holes 20A penetrating through the diaphragm in an optical axis A direction are formed so as to correspond to the convex parts 51A outside a central opening 20B. Therefore, the convex parts 51A are made to engage with the positioning holes 20A to be able to fixed while the diaphragm 20 is placed on the diaphragm placing surface 51B.SELECTED DRAWING: Figure 4

Description

The present invention relates to a lens unit having a configuration in which a plurality of lenses and an aperture are housed in a lens barrel.

For example, as an optical system used in an image pickup device mounted on an automobile, a surveillance camera, etc., a plurality of lenses are used as an optical axis (optical axis of the image pickup device) from the object side to the image side (image sensor side). Lens units that are stacked in the direction and fixed inside the lens barrel are used. At this time, the diaphragm and the light-shielding sheet for limiting the luminous flux are also fixed with the positional relationship with respect to the lens determined. This lens unit is designed so that an image of an object by visible light can be imaged well on an image sensor. Therefore, it is required that the positional relationship between each lens and the diaphragm in the lens unit is maintained with high accuracy and fixed to the lens barrel. When manufacturing this lens unit, for example, each lens, aperture, and light-shielding sheet are sequentially attached to the lens barrel side. At this time, the shapes of the lens barrel, the lens, and the like are set so that the lens and the like are not tilted and the above positional relationship is determined with high accuracy.

A lens unit satisfying such a requirement is described in, for example, Patent Document 1. Here, when mounting each lens on the lens barrel, only some lenses are press-fitted and fixed to the inner surface of the lens barrel in order to obtain high position accuracy in a state where the mounting is easy and there is no tilt. .. On the other hand, the other lens is fixed directly to the fixed lens or indirectly via another lens, and is not in contact with the inner surface of the lens barrel. At this time, the aperture provided on the most object side of the lens barrel and the light-shielding sheet provided between the lenses adjacent to each other in the optical axis direction on the image side of the aperture function as an aperture. At this time, among the aperture and the light-shielding sheet on the lens barrel side, the one that functions to substantially limit the luminous flux in this lens unit and the inclination of the adjacent lens have a particularly large effect on the imaging characteristics. Therefore, in the technique described in Patent Document 1, such a lens far from the aperture and the light-shielding sheet on the lens barrel side is press-fitted and fixed to the inner surface of the lens barrel as described above, and the aperture and the light-shielding sheet on the lens barrel side are fixed. The lens adjacent to the lens barrel is not in contact with the inner wall of the lens barrel as described above. As a result, a lens unit capable of stably obtaining good imaging characteristics can be obtained.

Japanese Unexamined Patent Publication No. 2013-205808

In the structure described in Patent Document 1, when a diaphragm (light-shielding sheet) that substantially limits the luminous flux is provided between the lenses and the diaphragm is sandwiched between adjacent lenses and installed, the adjacent lenses are installed. The interval between them is determined by the thickness of the aperture. In this case, since there are manufacturing variations in the thickness of the diaphragm, it is difficult to bring the positional relationship (interval) between adjacent lenses in the optical axis direction close to the design value (constant value). When the diaphragms were installed without being sandwiched between adjacent lenses and the lenses were fixed in this way, play in this diaphragm occurred in the optical axis direction. In this case, for example, when the diaphragm is tilted with respect to the optical axis, adverse effects on imaging characteristics such as ghosting occur.

As described above, in a lens unit having a configuration in which a diaphragm is arranged between adjacent lenses in the optical axis direction, it is difficult to determine the positional relationship between each lens and the diaphragm with high accuracy.

The present invention has been made in view of such a situation, and in a lens unit having a configuration in which a diaphragm is arranged between adjacent lenses in the optical axis direction, the positional relationship between each lens and between them and the diaphragm is highly accurate. The purpose is to determine in.

The lens unit according to the present invention includes a first lens group arranged on the object side along the optical axis, a second lens group arranged on the image side along the optical axis of the first lens group, and the above. The first lens group includes an aperture arranged between the first lens group and the second lens group, and a lens barrel that holds the first lens group, the aperture, and the second lens group. Of the lens adjacent to the object side that is most arranged on the image side and adjacent to the aperture in the optical axis direction, and the adjacent lens on the image side that is arranged closest to the object side and adjacent to the aperture in the optical axis direction of the second lens group. One is a one-sided lens made of glass, the other is a other-side lens made of a resin material, and the lens barrel is made of a resin material different from the other-side lens, and the object-side adjacent lens and the aperture are The image-side adjacent lens is housed in a lens housing portion provided in the lens barrel, and the one-side lens is supported by a lens holder on the outside as seen from the optical axis and housed in the lens housing portion. By engaging with the lens holder, the other side lens is fixed in the positional relationship between the one side lens in the optical axis direction and in the direction perpendicular to the optical axis, and the aperture has a circumference around the optical axis. A plurality of positioning holes are formed in the direction, and a plurality of convex portions projecting to the side where the aperture is located are formed on the side of the lens holder facing the aperture, and the aperture is formed. The convex portion is mounted on the lens holder in a state of being engaged with the positioning hole.

In this configuration, one of the object-side adjacent lens and the image-side adjacent lens, which is made of glass, is accommodated in the lens housing portion of the lens barrel in a form supported by the lens holder. The other side lens made of a resin material among the object side adjacent lens and the image side adjacent lens is engaged with the lens holder, so that the positional relationship with the one side lens is fixed. Further, the diaphragm is fixed to the lens holder in a state where the convex portion formed on the lens holder side and the positioning hole formed on the diaphragm side are engaged with each other. With the structure using such a lens holder, the positional relationship between the adjacent lens on the object side, the adjacent lens on the image side, and the diaphragm can be precisely determined, and a lens unit having good imaging characteristics can be easily manufactured.

Further, the length of the positioning hole along the circumferential direction around the optical axis is made larger than the length of the corresponding convex portion along the circumferential direction.
With this configuration, the work of attaching the diaphragm to the lens holder (adjacent lens on the image side) becomes easy.

Further, the one-sided lens is the image-side adjacent lens, and in the second lens group, an image-side lens adjacent to the image-side of the image-side adjacent lens is provided, and a plurality of lenses projecting to the image-side in the lens holder. The protrusions are provided, and the plurality of protrusions are divided into a plurality of protrusion groups according to the amount of protrusion, and the plurality of protrusions belonging to one protrusion group are attached to the image side lens on the image side. By being locked, the movement of the image-side adjacent lens to the image side is restricted.
In this configuration, the distance between the image-side lens and the image-side adjacent lens is determined by the amount of protrusion of the protrusion. At this time, if a plurality of protrusion groups having different protrusion amounts are provided so that only the protrusions of the selected protrusion group come into contact with the image-side lens, the interval can be finely adjusted. If the image-side lens is locked to the lens barrel side on the image side, the image-side adjacent lens is also indirectly locked to the lens barrel side.

Further, the lens holder is formed with a lens built-in hole which is a hole for accommodating the one-sided lens from the side opposite to the side where the diaphragm is located, and the one-sided lens has the diaphragm of the lens built-in hole. The diaphragm is fixed to the lens holder in a state of being locked by a lens fixing surface which is a bottom surface on the side and is formed in a plurality of dispersed directions in the circumferential direction around the optical axis, and the diaphragm is a region other than the convex portion in the lens holder. The region that is in contact with the diaphragm mounting surface and is fixed to the lens holder and is in contact with the one-sided lens on the lens fixing surface and the region that is in contact with the diaphragm on the diaphragm mounting surface are in the optical axis direction. It overlaps when viewed from the perspective.
In this configuration, the lens fixing surface is used to fix the one-sided lens, and the diaphragm mounting surface is used to fix the diaphragm from the opposite side to the lens holder. At this time, the optical axis of the one-sided lens, the diaphragm, and the lens holder is overlapped by overlapping the region of contact with the one-sided lens on the lens fixing surface and the region of contact with the diaphragm on the diaphragm mounting surface when viewed from the optical axis direction. The positional relationship in the direction can be determined particularly precisely.

Further, the surface of the lens holder on the side opposite to the side with the diaphragm is a groove dug down toward the side with the diaphragm, and the lens is viewed from the side opposite to the side with the diaphragm in the optical axis direction. A plurality of first adhesive grooves connected to the built-in hole are dispersed in the circumferential direction around the optical axis.
In this configuration, a plurality of first adhesive grooves are formed around the lens incorporating hole. When the one-side lens is joined in the lens built-in hole using an adhesive, excess adhesive on the side opposite to the side where the diaphragm is located can be accumulated in the first adhesive groove.

Further, inside the lens built-in hole, a plurality of ribs locally projecting toward the optical axis are formed in the circumferential direction around the optical axis so as to lock the one-sided lens from the outside when viewed from the optical axis. The surface of the lens holder on the side with the diaphragm is a groove dug down toward the side opposite to the side with the diaphragm, and overlaps with the rib when viewed from the side with the diaphragm in the optical axis direction. A plurality of notches are formed in a circumferential direction around the optical axis.
In this configuration, during assembly, the one-sided lens is press-fitted into the lens built-in hole in contact with the rib. In the portion where the rib is not formed in the circumferential direction, a notch portion is formed instead of the lens fixing surface. Therefore, it is possible to prevent fine chips generated by press-fitting from intervening between the lens fixing surface and the one-sided lens. Therefore, it is possible to suppress a decrease in the position accuracy of the one-side lens in the optical axis direction.

Further, an adhesive for fixing the one-sided lens to the lens holder is stored in the first adhesive groove or the notch.
In this configuration, not only the excess adhesive on the side opposite to the side with the squeeze is accumulated in the groove for the first adhesive, but also the excess adhesive on the side with the squeeze is accumulated in the notch. Therefore, a sufficient amount of adhesive can be applied so that the position of the one-sided lens with respect to the lens holder does not shift, and the adhesive is applied to the outside of the one-sided lens on the side of the lens holder where the aperture is located and on the opposite side. It is possible to prevent leakage.

Further, the other side lens and the lens holder are made of amorphous plastic, the lens barrel is made of crystalline plastic, and the other side lens is not in contact with the lens barrel.
In this configuration, since the other side lens and the lens holder are made of the same material, the lens body in which the one side lens is fixed to the lens holder can be treated in the same manner as the other side lens. Also, unlike the lens on the other side, the lens barrel is made of crystalline plastic with high weather resistance, so there is a difference in thermal expansion between the lens on the other side and the lens barrel, but these are non-contact. Therefore, this does not cause adverse effects such as distortion of the other side lens.

According to the present invention, in a lens unit having a configuration in which a diaphragm is arranged between adjacent lenses in the optical axis direction, the positional relationship between each lens and the diaphragm can be determined with high accuracy.

It is sectional drawing of the lens unit which concerns on embodiment. It is sectional drawing (a) and perspective view (b) of the lens barrel used in the lens unit which concerns on embodiment. It is an exploded assembly drawing of the lens unit which concerns on embodiment. It is a perspective view which shows the relationship between the diaphragm and the 5th lens body in the lens unit which concerns on embodiment. It is a perspective view seen from the image side of the lens holder in the lens unit which concerns on embodiment. FIG. 5 is a plan view of the fifth lens body of the lens unit according to the embodiment as viewed from the object side. FIG. 5 is a plan view of the lens holder unit (a) and the fifth lens body (b) in the lens unit according to the embodiment as viewed from the image side. It is sectional drawing along the optical axis of the 5th lens body in the lens unit which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view of the lens unit 1 according to the present embodiment along the optical axis A. Here, the object (Ob) side is the upper side in the figure, the image (Im) side is the lower side in the figure, and the image sensor 100 is located at the lowermost part in the figure. Each of the lenses L1 to L7 is directly or indirectly fixed to the lens barrel 10. In FIG. 1, the configuration for fixing each lens, the aperture 20, or between each lens and the lens barrel 10 is mainly described, and the positional relationship between the image sensor 100 and the lens barrel 10 is actually fixed. There is also a structure for this, but the description is omitted.

The image sensor 100 is a two-dimensional CMOS image sensor, and each pixel is arranged two-dimensionally in a plane perpendicular to the optical axis A. In reality, the image sensor 100 is covered with a cover glass (not shown). There is. In FIG. 1, a lens unit 1 including a first lens L1 to a seventh lens L7 is configured. The lens unit 1 is configured to form an image of visible light to be imaged on an image pickup device 100 (image plane) in a desired field of view and in a desired form.

In FIG. 1, the first lens L1 provided on the most object side (upper side in the drawing) is a fisheye lens, which mainly determines the field of view of the image pickup apparatus. A second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7 are sequentially arranged on the image sensor 100 side (image side). Each lens has a substantially symmetrical shape around the optical axis A. Further, a diaphragm 20 for limiting the luminous flux is provided between the fourth lens L4 and the fifth lens L5. Further, a light-shielding plate for removing unnecessary light is also appropriately provided between the second lens L2 and the third lens L3, but the description thereof is omitted in FIG.

2 (a) is a cross-sectional view of the lens barrel 10 along the optical axis A, and FIG. 2 (b) is a perspective view of the lens barrel 10 as viewed from the diagonally upper side (object side) in FIG. On the object side (upper side in the drawing) of the lens barrel 10, a first accommodating portion 10A having a substantially cylindrical inner peripheral surface is provided, and the bottom surface of the first accommodating portion 10A on the image side is the first lens L1. This is the first mounting portion 11 that comes into contact with the lens. Further, on the image side (lower side in the figure) of the first mounting portion 11, a substantially cylindrical cavity portion coaxial with the first accommodating portion 10A and having a smaller diameter than the first accommodating portion 10A. Two accommodating portions 10B are provided, and the bottom surface of the second accommodating portion 10B on the image side is a second mounting portion (mounting surface) 12 that comes into contact with the bonding lens L60 (image side lens described later). The central axis of the first accommodating portion 10A and the second accommodating portion 10B is common and is equal to the optical axis A. Further, as shown in FIG. 2A, the inner peripheral surface of the second accommodating portion 10B is actually gradually reduced from the object side to the image side.

In FIG. 1, the lens surfaces on the object side and the image side (the surface through which the light forming the image passes) in each lens are appropriately curved surfaces (convex curved surface, concave curved surface) so that the lens unit 1 provides desired imaging characteristics. ) It has been processed. Hereinafter, the lens surface on the object side of each lens is referred to as a first surface R1, and the lens surface on the image side is referred to as a second surface R2. Further, as the shape of the lens surface (convex curved surface or concave curved surface), the shape of the first surface R1 means the shape seen from the object side, and the shape of the second surface R2 means the shape seen from the image side. To do.

In general, there are two types of materials constituting a lens in such a small image pickup apparatus: glass and resin material. The former has high mechanical strength but is expensive, and the latter has low mechanical strength but is inexpensive. In addition, since the coefficient of thermal expansion of glass is smaller than that of resin materials, lenses that have a large effect on imaging characteristics (changes in focal position, etc.) due to minute changes in shape and position due to thermal expansion at high temperatures are glass. It is preferably made of. Therefore, in order to make the lens unit 1 high-performance and inexpensive, it is preferable that only the lens made of glass is made of glass and the other lenses are made of resin material.

From this point of view, in the present embodiment, since the first lens L1 arranged on the object side is located on the outermost surface of the image pickup apparatus 1, it is made of glass that is not easily scratched. Further, since the change in the focal length due to the temperature change appears remarkably in the lenses (fourth lens L4 and fifth lens L5) adjacent to the aperture 20, one of them (the fifth lens L5 in the present embodiment). Is made of glass. As the other lens, one made of an inexpensive resin material is used.

The first lens L1 is a negative lens in which the lens surface L1R1 on the object side is a convex curved surface and the lens surface L1R2 on the image side is a concave curved surface. On the upper surface side of the first lens L1, the lens surface L1R1 occupies almost the entire surface. On the lower surface side (image side) of the first lens L1, outside the lens surface L2R2, a first lens first lower surface L1A formed by a plane perpendicular to the optical axis A is provided. Further outside the first lower surface L1A of the first lens, a first lower surface L1B of the first lens located parallel to the first lower surface L1A of the first lens and closer to the object side (upper side in the drawing) than the first lower surface L1A is provided. Further, the outermost peripheral portion of the first lens L1 constitutes a cylindrical first lens outer peripheral surface L1C centered on the optical axis A. Of these surfaces, the lens surfaces L1R1 and L1R2 are optically used, and the other surface is used for fixing the first lens L1 to the lens barrel 10.

In FIG. 1, the upper end side of the lens barrel 10 is a first lens locking portion 13 bent toward the optical axis A (center) side so as to restrict the movement of the first lens L1 toward the object side. .. Further, the first lower surface L1A of the first lens comes into contact with the first mounting surface 11 of the lens barrel 10. Therefore, the positional relationship of the first lens L1 with respect to the lens barrel 10 in the optical axis A direction is determined by the first lens locking portion 13 on the object side (upper side in the figure) and first on the image side (lower side in the figure). It is determined by the mounting surface 11. At this time, on the outer side of the first lower surface L1A of the first lens, the gap between the second lower surface L1B of the first lens and the first mounting surface 11 was compressed and elastically deformed in the direction perpendicular to the optical axis A direction. By arranging the ring-shaped O-ring 30, a waterproof function inside the lens barrel 10 can be obtained. The shape of the first lens locking portion 13 as described above is the shape after processing (heat caulking) to fix the first lens l1 to the lens barrel 10, and the upper end of the lens barrel 10 before fixing. As shown in FIG. 2A, the shape of the portion side is such that the first lens L1 can be inserted into the lens barrel 10 from above as shown in FIG.

Further, the outer peripheral surface L1C of the first lens comes into contact with the inner peripheral surface of the first accommodating portion 10A in the lens barrel 10. As a result, the positional relationship between the first lens L1 and the lens barrel 10 in the direction perpendicular to the optical axis A is determined. That is, according to the above configuration, the first lens L1 is fixed to the lens barrel 10.

The second lens L2 is a negative lens in which the lens surface L2R1 on the object side is a convex curved surface and the lens surface L2R2 on the image side is a concave curved surface. On the object side (upper side in the figure) of the second lens L2, the outer side of the lens surface L2R1 is a plane that is perpendicular to the optical axis A and is located on the image side (lower side in the figure) with respect to the lens surface L2R1. The first upper surface L2A of the lens is provided. Further, on the image side (lower side in the drawing) of the second lens L2, a step portion (engagement structure) L2B composed of a surface parallel to the optical axis A and a surface perpendicular to the optical axis A is located outside the lens surface L2R2. Provided. The outer peripheral surface L2C of the second lens, which is the outermost surface of the second lens L2, comes into contact with the inner peripheral surface of the second accommodating portion 10B. The outer peripheral surface L2C of the second lens is formed in a substantially conical surface shape so that the inner diameter around the optical axis A gradually decreases toward the image side. As a result, the positional relationship between the second lens L2 and the lens barrel 10 in the direction perpendicular to the optical axis A is determined.

Further, in the region inside the first mounting portion 11 (the side closer to the optical axis A) and outside the lens surface L1R2 and the lens surface L2R1, the second lens first upper surface L2A and the first lens second lower surface L1B An elastic member 40 composed of an elastic body and thin in the direction of the optical axis A is arranged between them. That is, the first lens L1 and the second lens L2 do not come into direct contact with each other in the direction along the optical axis A, and an elastic member 40 is provided between them.

The third lens L3 is a positive lens in which the lens surface L3R1 on the object side is a concave curved surface and the lens surface L3R2 on the image side is a convex curved surface. On the object side (upper side in the drawing) of the third lens L3, a step portion (engagement structure) L3A formed so as to engage with the step portion L2B of the second lens L2 is provided on the outside of the lens surface L3R1. .. Further, on the image side (lower side in the drawing) of the third lens L3, a step portion (engagement structure) L3B composed of a surface parallel to the optical axis A and a surface perpendicular to the optical axis A is located outside the lens surface L3R2. Provided. Further, the outer peripheral surface L3C of the third lens, which is a substantially cylindrical surface forming the outermost outer circumference of the third lens L3, is not in contact with the inner peripheral surface of the second accommodating portion 10B.

The fourth lens L4 is a positive lens in which the surface L4R1 on the object side is a concave curved surface and the surface L4R2 on the image side is a convex curved surface. On the object side (upper side in the drawing) of the fourth lens L4, a step portion (engagement structure) L4A formed so as to engage with the step portion L3B of the third lens L3 is provided on the outside of the lens surface L4R1. .. Further, on the image side (lower side in the drawing) of the fourth lens L4, a step portion (engagement structure) L4B composed of a surface parallel to the optical axis A and a surface perpendicular to the optical axis A is located outside the lens surface L4R2. Provided. Further, the outer peripheral surface L4C of the fourth lens, which is a substantially cylindrical surface forming the outermost outer circumference of the fourth lens L4, is not in contact with the inner peripheral surface of the second accommodating portion 10B. That is, the third lens L3 and the fourth lens L4 are not in contact with the lens barrel 10.

As described above, the fifth lens L5 is a positive lens made of glass, the surface L5R1 on the object side having a convex curved surface, and the surface L5R2 on the image side having a convex curved surface. However, unlike other lenses, the fifth lens L5 is housed in the lens barrel 10 in a state of being a fifth lens body L50 which is press-fitted and fixed to a lens holder 51 made of a resin material and integrated. That is, the fifth lens L5 is treated as a lens in the same state as the third lens L3 and the fourth lens L4 made of the resin material in the state of being the fifth lens body L50.

On the object side (upper side in the drawing) of the fifth lens body L50, a step portion (engagement) formed so as to engage with the step portion L4B of the fourth lens L4 on the outer lens holder 51 of the fifth lens L5. Structure) L50A is provided. Further, on the image side (lower side in the figure) of the fifth lens body L50, the protruding portion L50B locally projecting outward from the fifth lens L5 toward the image side (lower side in the figure) than the surroundings. Is provided. Details of the protrusion L50B will be described later. Further, the outer peripheral surface L50C of the fifth lens body, which is the outermost surface of the fifth lens body L50, comes into contact with the inner peripheral surface of the second accommodating portion 10B. The outer peripheral surface L50C of the fifth lens body is formed in a substantially conical surface shape so that the inner diameter around the optical axis A gradually decreases toward the image side. As a result, the positional relationship between the fifth lens body L50 (fifth lens L5) and the lens barrel 10 in the direction perpendicular to the optical axis A is determined.

The sixth lens L6 is a negative lens in which the surface L6R1 on the object side is a concave curved surface and the surface L6R2 on the image side is a concave curved surface. The seventh lens L7 is a positive lens having an outer diameter smaller than that of the sixth lens L6, the surface L7R1 on the object side having a convex curved surface, and the surface L7R2 on the image side having a convex curved surface. Further, the sixth lens L6 and the seventh lens L7 are set so as to form a bonded lens (image side lens) L60 closest to the image side by fitting and joining the opposing lens surfaces. That is, the image-side lens, which is substantially the most image-side lens, is a junction in which the image-side lens surface L6R2 of the sixth lens L6 and the object-side lens surface L7R1 of the seventh lens L7 are fitted and joined. It becomes the lens L60.

On the object side (upper side in the drawing) of the bonded lens L60 (sixth lens L6), on the outside of the lens surface L6R1, a bonded lens upper surface L6A which is a flat surface in contact with the protruding portion L50B of the fifth lens body L50 is provided. In FIG. 1, for convenience, the protrusions L50B are shown to be in contact with the upper surface L6A of the junction lens on both sides of the optical axis A, but the actual details will be described later.

Further, on the image side (lower side in the drawing) of the bonded lens L60 (sixth lens L6), a bonded lens lower surface L6B which is a plane perpendicular to the optical axis A is provided outside the lens surface L7R2. The lower surface L6B of the bonded lens comes into contact with the second mounting portion (mounting surface) 12. The sixth lens outer peripheral surface L6C, which is the outermost surface of the bonded lens L60 (sixth lens L6), comes into contact with the inner peripheral surface of the second accommodating portion 10B. The outer peripheral surface L6C of the sixth lens is formed in a substantially conical surface shape so that the inner diameter around the optical axis A gradually decreases toward the image side. Therefore, the position of the bonded lens L60 in the direction along the optical axis A is limited by the lens barrel 10 (second mounting portion 12) on the image side.

In this case, since the fifth lens body L50 (protruding portion L50B) is locked to the junction lens L60 on the image side, the position of the fifth lens body L50 in the direction along the optical axis A is the junction lens L60 on the image side. It is limited by the second mounting portion 12 (lens barrel 10) via.

Further, according to the above configuration, the position of the fourth lens L4 in the direction along the optical axis A is such that the step portion L4B and the step portion L50A engage with each other, so that the fifth lens body L50 and the junction lens L60 are placed on the image side. Limited by the lens barrel 10 through. On the other hand, the position of the fourth lens L4 in the direction perpendicular to the optical axis A is determined by the inner peripheral surface of the second accommodating portion 10B via the fifth lens body L50 by engaging the step portion L4B and the step portion L50A. It is decided. Similarly, the position of the third lens L3 in the direction along the optical axis A is such that the step portion L3B and the step portion L4A engage with each other, so that the fourth lens L4, the fifth lens body L50, and the junction lens L60 are formed on the image side. It is limited by the lens barrel 10 via. On the other hand, the position of the third lens L3 in the direction perpendicular to the optical axis A is such that the step portion L3B and the step portion L4A engage with each other, so that the second accommodating portion 10B passes through the fourth lens L4 and the fifth lens body L50. It is determined by the inner peripheral surface of.

Further, according to the above configuration, the position of the second lens L2 in the direction along the optical axis A is such that the step portion L2B and the step portion L3A engage with each other, so that the third lens L3 and the fourth lens L4 on the image side. It is limited by the lens barrel 10 via the fifth lens body L50 and the junction lens L60. On the other hand, the position of the second lens L2 in the direction perpendicular to the optical axis A is determined by the inner peripheral surface of the second accommodating portion 10B as described above.

That is, in the above configuration, of the second lens L2 to the junction lens L60 (seventh lens L7), the second lens L2, the fifth lens L5 (fifth lens body L50), and the junction lens L60 have outer peripheral portions thereof. It is a contact lens that comes into contact with the inner peripheral surface of the second accommodating portion 10B of the lens barrel 10. These contact lenses thereby fix the positional relationship between the lens barrel 10 in the direction perpendicular to the optical axis A. On the other hand, the third lens L3 and the fourth lens L4 are non-contact lenses that do not come into direct contact with the inner peripheral surface of the second accommodating portion 10B. The non-contact lens is perpendicular to the optical axis A between the contact lens by directly or indirectly engaging with the contact lens on the object side or the image side via the step portion (engagement structure) as described above. By fixing the positional relationship in the above direction, the positional relationship with the lens barrel 10 in this direction is fixed. As a result, the positional relationship between all the second lens L2 to the junction lens L60 (seventh lens L7) and the lens barrel 10 in the direction perpendicular to the optical axis A is fixed.

On the other hand, the outer peripheral surfaces of the third lens L3 and the fourth lens L4 are not in contact with the inner peripheral surface of the second accommodating portion 10B. Therefore, it is suppressed that a force is applied to the third lens L3, the fourth lens L4 (lens system), and the lens barrel 10 due to the difference in thermal expansion between the third lens L3, the fourth lens L4, and the lens barrel 10. Will be done. Therefore, distortion of the lens due to the difference in thermal expansion is suppressed, and the adverse effect of the temperature change on the imaging characteristics is reduced.

FIG. 3 is an exploded perspective view of the lens unit 1, and here, a light-shielding plate 21 whose description is omitted in FIG. 1 is also described. Here, the junction lens L60, the fifth lens body L50, the aperture 20, the fourth lens L4, the third lens L3, the shading plate 21, the second lens L2, the elastic member 40, the O-ring 30, and the first lens L1 are shown in the drawing. It is sequentially attached to the lens barrel 10 from the upper side (object side). As shown, the elastic member 40 and the O-ring 30 are annular.

As the material of the lens barrel 10, crystalline plastics (polyethylene, polyamide, polytetrafluoroethylene) having excellent weather resistance are preferably used. On the other hand, the second lens L2, the third lens L3, the fourth lens L4, the sixth lens L6, and the seventh lens L7 are amorphous plastics (polycarbonate, etc.) having excellent lens performance (light transmission and moldability). Consists of. Further, since the lens holder 51 is made of the same amorphous plastic as the fourth lens L4 and the like, the fifth lens body L50 can be treated as a plastic lens similar to the fourth lens L4 and the like as a whole. As described above, the first lens L1 and the fifth lens L5 are made of glass.

In the lens unit 1, the aperture 20, the fifth lens body L50 (lens holder 51), and the surrounding structure thereof are particularly shaped so as to facilitate maintaining their positional relationship appropriately. This point will be described below.

In the lens unit 1, the diaphragm 20 is mounted on the fifth lens body L50 (lens holder 51) in a highly reproducible and highly accurate positional relationship. The structure for this purpose will be described below. In the above description, the description is mainly based on the structure after assembly of FIG. 1, whereas in the following, each component before assembly will be mainly described. At this time, the optical axis A, the object side, the image side, and the like mean those in the case where each component is arranged in FIG.

FIG. 4 is a perspective view of the diaphragm 20 and the fifth lens body L50 as viewed from the object side. As shown in FIG. 4, three convex portions 51A having a circular cross-sectional shape perpendicular to the optical axis A are formed on the object side of the lens holder 51 at equal intervals in the circumferential direction. Further, the periphery of the convex portion 51A is a plane (aperture mounting surface 51B) perpendicular to the optical axis A. On the other hand, the thin flat diaphragm 20 is formed with three positioning holes 20A penetrating the aperture 20 in the direction of the optical axis A so as to correspond to the convex portion 51A on the outside of the central opening 20B. Therefore, the positioning hole 20A can be engaged with the convex portion 51A, and the diaphragm 20 can be fixed in a state of being mounted on the diaphragm mounting surface 51B. At this time, for example, the diaphragm 20 is fixed to the lens holder 51 (fifth lens body L50) by melting the convex portion 51A protruding from the positioning hole 20A toward the object side after mounting the diaphragm 20 and fusing it with the surroundings. Can be done. In FIG. 1, the diaphragm 20 is provided perpendicular to the optical axis A, and when this angle fluctuates, ghosts may occur in the image pickup apparatus. On the other hand, with such a configuration, the diaphragm 20 is fixed to the fifth lens body L50 in an appropriate manner, and the angle of the diaphragm 20 with respect to the optical axis A is suppressed from fluctuating. In the above example, the convex portion 51A has a circular shape, but more generally, the length of the positioning hole 20A along the circumferential direction around the optical axis A includes the case where this shape is not circular. , It may be set longer than the length of the convex portion 51A along the same direction. This facilitates the work of attaching the diaphragm to the lens holder, and does not cause an adverse effect on the imaging characteristics.

At this time, as shown in FIG. 4, the positioning hole 20A is formed longer in the circumferential direction around the optical axis A than in the radial direction of the optical axis A. As a result, the diaphragm 20 can be rotated by a small amount around the optical axis A while the diaphragm 20 is mounted, so that the diaphragm 20 can be mounted on the fifth lens body L50 particularly easily. On the other hand, if the opening 20B of the aperture 20 is circular around the optical axis A, the condition of the opening 20B does not change even during the above rotation, so that even if the aperture 20 rotates in this way, an image is formed. There is no adverse effect on the characteristics. Therefore, with this configuration, the aperture 20 can be fixed to the lens holder 51 with good reproducibility and high accuracy.

Further, as described above, the lens holder 51 is fixed to the lens barrel 10 in a state where the fifth lens L5 is supported by the lens holder 51. Therefore, in order to improve the position accuracy of the fifth lens L5 with respect to the lens barrel 10, it is necessary to fix the fifth lens L5 to the lens holder 51 with high position accuracy. The structure of the lens holder 51 for this purpose will be described below.

FIG. 5 is a perspective view of the lens holder 51 alone as viewed from the image side. Further, FIG. 6 is a plan view of the lens holder 51 (fifth lens body L50) in a state where the fifth lens L5 is mounted, as viewed from the object side, and FIG. 7 is a plan view of the lens holder 51 as viewed from the image side. It is a plan view (a: a lens holder 51 alone, b: a state in which a fifth lens L5 is attached).

As shown in FIG. 5, in the lens holder 51, a lens built-in hole 51C which is a hole for accommodating the fifth lens L5 from the image side is formed, and the fifth lens L5 is formed in the lens built-in hole 51C. It is locked on the object side by the lens fixing surface 51D which is the bottom surface on the object side. That is, the fifth lens L5 is locked to the lens holder 51 by the lens fixing surface 51D on the object side in the direction of the optical axis A. As shown in FIG. 7A, the lens fixing surface 51D is formed along the outer peripheral portion of the fifth lens L5, but is divided into three in the circumferential direction.

Further, in the lens incorporating hole 51C, the outer peripheral portion of the fifth lens L5 comes into contact with the rib 51E locally protruding toward the optical axis A side as shown in FIG. As shown in FIGS. 6 and 7B, three ribs 51E are formed at locations where the lens fixing surface 51D is not provided in the circumferential direction. That is, in the direction perpendicular to the optical axis A, the fifth lens L5 is fixed to the lens holder 51 by being locked around by three ribs 51E.

In FIG. 5, three small claw-shaped lens fall prevention portions 51F bent toward the optical axis A side are provided in the circumferential direction as in the case of the first lens locking portion 13. However, unlike the first lens locking portion 13, this lens fall prevention portion 51F does not come into contact with the fifth lens L5 and is not used for supporting (fixing) the fifth lens L5.

Further, as shown in FIG. 7, on the image side of the lens holder 51, a portion (groove) dug down with respect to the lens holder bottom surface 51G, which is the bottom surface perpendicular to the optical axis A, outside the lens built-in hole 51C. The first adhesive groove 51H is formed in a portion where the rib 51E is not formed in the circumferential direction. Six first adhesive grooves 51H are formed at equal intervals in the circumferential direction so as to be connected to the lens incorporating holes 51C. Further, as shown in FIG. 4, on the object side of the lens holder 51, a portion (groove) is dug down on the outside of the lens built-in hole 51C with respect to the aperture mounting surface 51B which is the bottom surface perpendicular to the optical axis A. ), A groove (notch portion) 51J for the second adhesive is formed. As shown in FIG. 6, three second adhesive grooves 51J are formed at equal intervals in the circumferential direction in the portion where the ribs 51E are formed in the circumferential direction so as to be connected to the lens incorporating hole 51C. There is.

Further, FIG. 8 is a cross-sectional view in the BB direction in FIG. 6 (a state in which the fifth lens L5 is attached). In FIG. 8, the left side with respect to the optical axis A shows a cross section of a portion having a lens fixing surface 51D and not having a rib 51E and a second adhesive groove 51J. The right side with respect to the optical axis A shows a cross section of a portion without a lens fixing surface 51D and having a rib 51E and a second adhesive groove 51J. Further, as will be described later, the fifth lens L5 is actually fixed in the lens incorporating hole 51C by using an adhesive, but the description of this adhesive is omitted in FIG.

As shown in FIGS. 6 and 8, the lens fixing surface 51D supporting the fifth lens L5 and the diaphragm mounting surface 51B fixing the diaphragm 20 are formed so as to overlap each other when viewed from the direction of the optical axis A. .. In this way, the region of contact with the fifth lens L5 on the lens fixing surface 51D and the region of contact with the diaphragm 20 on the diaphragm mounting surface 51B are configured to overlap when viewed from the optical axis A direction, thereby making the lens holder. The positional relationship between the 51, the fifth lens L5, and the aperture 20 in the optical axis A direction can be precisely determined.

Further, in FIG. 8, the outer peripheral portion of the fifth lens L5 and the lens holder 51 side (inner surface of the lens built-in hole 51C) are separated from each other on the left side of the optical axis A (the portion where the rib 51E is not provided) and are on the right side. Is in contact with the rib 51E. Actually, the gap between the outer peripheral portion of the fifth lens L5 and the inner surface of the lens incorporating hole 51C in the place where the rib 51E is not provided is filled with the adhesive, and the adhesive solidifies. The fifth lens L5 is fixed to the lens holder 51. As described above, in the circumferential direction, a plurality of portions (ribs 51E) in which the outer peripheral portion of the fifth lens L5 and the inner surface of the lens incorporating hole 51C are in contact with each other and a plurality of portions in which a narrow gap is formed between them are provided. The positional relationship between the fifth lens L5 and the lens holder 51 in the direction perpendicular to the optical axis A can be determined, and the adhesive in the gap can firmly bond them.

In the work of fixing the fifth lens L5 to the lens holder 51, first, the fifth lens L5 is press-fitted into the lens built-in hole 51C so as to be locked to the rib 51E and the lens fixing surface 51D as described above. Lens. After that, the adhesive before solidification is applied to the first adhesive groove 51H, and the adhesive is solidified after the adhesive is supplied to the voids from here.

As described above, the first adhesive groove 51H is used for supplying the adhesive. Further, the excess adhesive leaking to the image side is housed in the first adhesive groove 51H. By providing a plurality of first adhesive grooves 51H as described above and reducing the individual areas, the adhesive leaks to the outside of the first adhesive groove 51H due to the surface tension of the adhesive before solidification. Is suppressed. The adhesive inside the first adhesive adoption groove 51H solidifies at the same time as the adhesive between the outer peripheral portion of the fifth lens L5 and the inner surface of the lens incorporating hole 51C. As a result, it is possible to prevent the adhesive leaking to the image side from adhering to, for example, the protruding portion L50B and hardening, thereby adversely affecting the positional relationship between the fifth lens body L50 and the bonded lens L60.

The same applies to the second adhesive groove 51J formed on the object side. That is, the excess adhesive before solidification that leaked to the object side is accommodated in the second adhesive groove 51J, and the adhesive adheres to the diaphragm mounting surface 51B, which adversely affects the positional relationship between the diaphragm 20 and the lens holder 51. Is suppressed. Further, if necessary, the adhesive before solidification may be supplied to the second adhesive groove 51J before joining.

Further, since the rib 51E is formed so that the outer peripheral surface of the fifth lens L5 and the three ribs 51E are in contact with each other, in the above assembly work, the fifth lens L5 is viewed from the image side with respect to the lens incorporating hole 51C. It is press-fitted. Since the lens holder 51 is made of a resin material, small chips may be discharged particularly toward the object side at this time. As described above, when the second adhesive groove (notch portion) 51J is provided so as to overlap the rib 51E, the lens fixing that locks the fifth lens L5 on the object side at the place where the rib 51E exists. A second adhesive groove (notch portion) 51J will be provided instead of the surface 51D. Therefore, it is possible to prevent the chips from intervening between the lens fixing surface 51D and the fifth lens L5, and the chips are housed in the second adhesive groove 51J.

Next, a structure for maintaining the positional relationship between the fifth lens body L50 (fifth lens L5) and the junction lens L60 on the image side with high accuracy will be described. As shown in FIG. 1, in the fifth lens body L50, the protruding portion L50B formed on the lens holder 51 abuts on the upper surface L6A of the bonding lens of the bonding lens L60, so that the fifth lens body L50 and the fifth lens L5 in the optical axis A direction thereof The distance between the junction lenses L60 is fixed. In order to obtain good imaging characteristics, it is required to bring this interval close to a predetermined design value with high accuracy.

Here, as described above, the fifth lens L5 is made of glass. In general, a glass lens is polished so that its lens surface is formed into a predetermined shape with high accuracy. On the other hand, the thickness of the lens is several μm or less in the case of a plastic lens manufactured by resin molding, whereas it is coarser and several tens of μm in the case of a glass lens. Become. This variation in thickness can be compensated for by finely adjusting the distance between the fifth lens L5 and the adjacent lens (junction lens L60).

Here, as shown in FIG. 5, the projecting portions L50B are formed at 21 equal intervals in the circumferential direction, and each of the projecting portions L50B is composed of three projecting portions L50B (projecting portion group) to L50B7. It is classified into a group consisting of, according to the amount of protrusion toward the image side. This protrusion amount is set to increase from L50B1 to L50B7. Therefore, when manufacturing this lens unit 1, the fifth lens L5 and the bonded lens L60 are combined according to the actually measured thickness of the fifth lens L5 after being bonded to the lens holder 51 as described above. The protruding portion L50B that actually abuts on the upper surface L6A of the bonded lens can be selected from the above L50B1 to L50B7 so that the interval between them becomes an appropriate value. At this time, the protruding portion L50B of the protruding portion group having a larger protruding amount than the selected protruding portion group can be mechanically removed. Since the protrusions L50B1 to L50B7 are formed on the lens holder 51 made of a resin material, such processing can be easily performed. Further, if three protrusions L50B1 to L50B7 are provided as shown in the drawing, the fifth lens body 51 can be supported by three points on the junction lens L60, so that the fifth lens L5 and the junction lens L60 can be supported. The interval can be determined with high accuracy after compensating for the variation in the thickness of the fifth lens L5 as described above. The same applies not only to variations in the thickness of the fifth lens L5, but also to variations in the manufacturing of the bonded lens L60 and the lens barrel 10. On the other hand, when the outer peripheral surface L50C of the fifth lens body comes into contact with the inner peripheral surface of the second accommodating portion 10B, the positional relationship of the fifth lens L5 (fifth lens body L50) with respect to the lens barrel 10 in the direction perpendicular to the optical axis A. Is fixed.

On the other hand, as for the positional relationship between the fourth lens L4 and the fifth lens L5 (of the fifth lens body L50) in the optical axis A direction and the direction perpendicular to the optical axis A, as described above, the stepped portion L4B is the fifth lens body L50. It is determined by engaging with the step portion L50A of. Therefore, according to the above configuration, the positional relationship between the fourth lens L4, the aperture 20, the fifth lens body L50, the junction lens L60, and the inner peripheral surface (lens barrel 10) of the second accommodating portion 10B around them is It is decided. Further, since the fourth lens L4 and the lens barrel 10 are made of different resin materials, the coefficient of thermal expansion is different, and although there is a difference in thermal expansion (difference in expansion and contraction) between them when the temperature changes, Since these are non-contact, this difference in thermal expansion does not cause an adverse effect such as distortion on the fourth lens L4.

At this time, the fifth lens body L50 is configured by mounting the lens holder 51 around the small-diameter fifth lens L5, and the lens holder 51 is made of the same resin material as the fourth lens and the like. Since the fifth lens L5 has a small diameter and is made of glass, its coefficient of thermal expansion is small, the amount of expansion and contraction of the fifth lens L5 when there is a temperature fluctuation is small, and the lens holder 51 and the fourth lens L4 Is made of the same resin material, so that the difference in thermal expansion between the fifth lens body L50 and the fourth lens L4 is substantially small. In the above configuration, the fourth lens L4 engages with the fifth lens body L50 (lens holder 51) by an engaging structure in order to determine the positions of the fourth lens L4 in the optical axis A direction and the direction perpendicular to the optical axis A. However, since the difference in thermal expansion between them is small in this way, it is possible to suppress the occurrence of adverse effects such as distortion on the fourth lens L4 when the temperature changes. Therefore, in the above lens unit 1, good imaging characteristics are maintained even when there is a temperature fluctuation.

In the above example, the fifth lens L5 (image side adjacent lens) is a glass lens (one side lens), and the fourth lens L4 (object side adjacent lens) is a resin material lens (other side lens). However, conversely, the object-side adjacent lens may be made of glass and the image-side adjacent lens may be made of resin material. In this case, the same lens holder as above may be used on the adjacent lens side on the object side, and the aperture may be attached to this lens holder in the same manner as above. Further, the lens holder is fixed to the inner peripheral surface of the second accommodating portion, the image side adjacent lens is not in contact with the inner peripheral surface, and the image side adjacent lens is the object side adjacent lens as described above. It may be engaged with the lens holder). However, it is preferable that the adjacent lens on the image side is made of glass because the fluctuation of the angle of view due to the temperature change can be suppressed more effectively.

(Main features of this form)
The features of this embodiment are briefly summarized as follows.
(1) The lens unit 1 has a first lens group (first lens L1 to fourth lens L4) arranged on the object (Ob) side along the optical axis A, and an optical axis A more than the first lens group. The second lens group (fifth lens L5 to seventh lens L7) arranged on the image (Im) side along the image (Im), the aperture 20 arranged between the first lens group and the second lens group, and the first lens group. A lens group, an aperture 20, and a lens barrel 10 for holding a second lens group are provided, and an object-side adjacent lens (first) adjacent to the aperture 20 in the optical axis A direction and arranged on the image side of the first lens group. Of the four lenses L4) and the image-side adjacent lens arranged on the object side closest to the second lens group and adjacent to the aperture 20 in the optical axis A direction, one is made of glass and the other is made of resin material. The other-side lens, and the lens barrel 10 is made of a resin material different from that of the other-side lens, and the object-side adjacent lens, the aperture 20, and the image-side adjacent lens are lens accommodating portions provided in the lens barrel. The lens is housed in the second housing section 10B), the one-sided lens is supported by the lens holder 51 on the outside as seen from the optical axis, and is housed in the lens housing section (second housing section 10B), and the other-side lens is housed in the lens holder 51. By engaging with, the positional relationship between the optical axis A direction and the one-sided lens in the direction perpendicular to the optical axis A is fixed, and the aperture 20 has a plurality of positioning holes in the circumferential direction around the optical axis A. 20A is formed, and on the side of the lens holder 51 facing the aperture 20, a plurality of convex portions 51A projecting to the side where the aperture 20 is located are formed corresponding to the positioning holes 20A, and the aperture 20 has the convex portions 51A. It is attached to the lens holder 51 in a state of being engaged with the positioning hole 20A.

In this configuration, the lens barrel 10 is a glass-made one-sided lens (fifth lens L5 in the case of this embodiment) of the object-side adjacent lens and the image-side adjacent lens supported by the lens holder 51. It is housed in the lens housing part 10B of. The other-side lens (fourth lens L4 in the case of this embodiment) made of a resin material is engaged with the lens holder 51 to fix the positional relationship with the one-side lens. Further, the diaphragm 20 is fixed to the lens holder 51 in a state where the convex portion 51A formed on the lens holder 51 side and the positioning hole 20A formed on the diaphragm 20 side are engaged with each other. With such a structure using the lens holder 51, the positional relationship between the fourth lens L4, the fifth lens L5, and the aperture 20 can be precisely determined, and a lens unit having good imaging characteristics can be easily manufactured. ..

(2) The length of the positioning hole 20A along the circumferential direction around the optical axis A is made larger than the length along the circumferential direction of the corresponding convex portion 51A.
With this configuration, the work of mounting the diaphragm 20 on the lens holder 51 (fifth lens L5 side) becomes easy.

(3) The one-side lens is an image-side adjacent lens (fifth lens L5), and in the second lens group, an image-side lens L60 is provided adjacent to the image side of the image-side adjacent lens (fifth lens L5). The lens holder 51 is provided with a plurality of projecting portions L50B protruding toward the image side, and the plurality of projecting portions L50B are divided into a plurality of projecting portion groups (L50B1 to L50B7) according to the amount of projecting, and one projecting portion group. By locking the plurality of projecting portions L50B belonging to the image side to the image side lens L60 on the image side, the movement of the image side adjacent lens (fifth lens L5) to the image side is restricted.

In this configuration, the distance between the image-side lens L60 and the image-side adjacent lens (fifth lens L5) is determined by the amount of protrusion of the protrusion L50B. At this time, if a plurality of protrusion groups (L50B1 to L50B7) having different protrusion amounts are provided so that only the protrusions L50B of the selected protrusion group come into contact with the image side lens L60, fine adjustment of this interval can be performed. It can be carried out. On the other hand, if the image-side lens L60 is locked to the lens barrel 10 side on the image side, the image-side adjacent lens (fifth lens L5) is also indirectly locked to the lens barrel 10 side.

(4) The lens holder 51 is formed with a lens built-in hole 51C which is a hole for accommodating a one-sided lens (fifth lens L5) from the side opposite to the side where the aperture 20 is located, and a one-sided lens (fifth lens L5). ) Is the bottom surface of the lens built-in hole 51C on the side where the diaphragm 20 is located, and is fixed to the lens holder 51 in a state of being locked by a lens fixing surface 51D formed in a plurality of directions in the circumferential direction around the optical axis A. The diaphragm 20 is fixed to the lens holder 51 in contact with the diaphragm mounting surface 51B, which is a region other than the convex portion 51A of the lens holder 51, and is in contact with the one-side lens (fifth lens L5) on the lens fixing surface 51D. And the region of the diaphragm mounting surface 51B that comes into contact with the diaphragm 20 overlaps with each other when viewed from the optical axis A direction.

In this configuration, the lens fixing surface 51D is used to fix the one-sided lens (fifth lens L5), and the aperture mounting surface 51B is used to fix the diaphragm 20 to the lens holder 51 from opposite sides. .. At this time, the region of contact with the one-sided lens (fifth lens L5) on the lens fixing surface 51D and the region of contact with the diaphragm 20 on the diaphragm mounting surface 51B are overlapped with each other when viewed from the optical axis A direction. The positional relationship between the side lens (fifth lens L5), the diaphragm 20, and the lens holder 51 in the optical axis A direction can be determined particularly precisely.

(5) The surface of the lens holder 51 opposite to the side with the aperture 20 is a groove dug down toward the side with the aperture, and the lens is viewed from the side opposite to the side with the aperture 20 in the optical axis A direction. A plurality of first adhesive grooves 51H connected to the built-in hole 51C are dispersed in the circumferential direction around the optical axis A.
In this configuration, a plurality of first adhesive grooves 51H are formed around the lens incorporating hole 51C. When joining one side lens (fifth lens L5) with an adhesive in the lens built-in hole 51C, the adhesive or excess adhesive supplied for joining on the side opposite to the side where the aperture 20 is located. Can be stored in the first adhesive groove 51H.

(6) Inside the lens built-in hole 51C, a rib 51E that locally protrudes toward the optical axis A so as to lock the one-sided lens (fifth lens L5) from the outside as viewed from the optical axis A is optical. A plurality of grooves are formed in the circumferential direction around the axis A, and the surface of the lens holder 51 on the side where the diaphragm 20 is located is a groove dug down toward the side opposite to the side where the diaphragm 20 is located. A plurality of cutout portions 51J that overlap with the rib 51E when viewed from the side where the 20 is located are formed so as to be dispersed in the circumferential direction around the optical axis A.
In this configuration, at the time of assembly, the one-side lens (fifth lens L5) is press-fitted into the lens incorporating hole 51C in a state of being in contact with the rib 51E. It is possible to prevent the chips generated at this time from adhering to the lens fixing surface 51D, and to collect the chips in the notch portion 51J.

(7) An adhesive for fixing the one-side lens (fifth lens L5) to the lens holder 51 is stored in the groove 51H for the first adhesive or the notch 51J.
In this configuration, not only the excess adhesive on the side opposite to the side where the drawing 20 is located is accumulated in the first adhesive groove 51H, but also the excess adhesive on the side where the drawing 20 is located is accumulated in the notch 51J. Be done. These can be used in the same way in the supply of the adhesive used for joining.

(8) The other side lens (fourth lens L4) and the lens holder 51 are made of amorphous plastic, the lens barrel 10 is made of crystalline plastic, and the other side lens (fourth lens L4) is the lens barrel 10. It is said to be non-contact.
In this configuration, since the other side lens (fourth lens L4) and the lens holder 51 are made of the same material, the one side lens (fifth lens L5) is fixed to the lens holder 51. The fifth lens body L50) can be treated in the same manner as the other side lens (fourth lens L4). Further, since the lens barrel 10 is made of crystalline plastic having high weather resistance unlike the other side lens (fourth lens L4), heat is generated between the other side lens (fourth lens L4) and the lens barrel 10. Although expansion differences occur, since they are non-contact, adverse effects such as distortion of the other side lens (fourth lens L4) do not occur.

In addition to the above examples, it is possible to construct a lens system including the above-mentioned object-side adjacent lens, diaphragm, image-side adjacent lens, and the like. At this time, the number of other lenses in the lens system is arbitrary.

The present invention has been described based on an embodiment and a modification thereof, but this embodiment is an example, and various modifications can be made to the combination of each component thereof, and such a modification is also described in the present invention. It will be understood by those skilled in the art that it is within the scope of the invention.

1 Lens unit 10 Lens barrel 10A 1st housing 10B 2nd housing (lens housing)
11 1st mounting part 12 2nd mounting part (mounting surface)
13 1st lens locking part 20 Aperture 20A Positioning hole 20B Opening 21 Shading plate 30 O ring 40 Elastic member 51 Lens holder 51A Convex part 51B Aperture mounting surface 51C Lens built-in hole 51D Lens fixing surface 51E Rib 51F Lens fall prevention part 51G Lens holder bottom surface 51H 1st adhesive groove 51J 2nd adhesive groove (notch)
100 Image sensor A Optical axis Im image (side)
L1 1st lens L1A 1st lens 1st lower surface L1B 1st lens 2nd lower surface L1C 1st lens outer peripheral surface L2 2nd lens L2A 2nd lens 1st upper surface L2B, L3A, L3B, L4A, L4B, L50A Stepped portion Combined structure)
L2C 2nd lens outer peripheral surface L3 3rd lens L3C 3rd lens outer peripheral surface L4 4th lens (object side adjacent lens)
L4C 4th lens outer peripheral surface L5 5th lens (image side adjacent lens)
L6 6th lens L6A Upper surface of the bonded lens L6B Lower surface of the bonded lens L6C Outer surface of the 6th lens L7 7th lens L50 5th lens body (adjacent lens on the image side)
L50B, L50B1 to L50B7 Protruding part L50C 5th lens body outer peripheral surface L60 junction lens (image side lens)
Ob object (side)
R1 first surface R2 second surface

Claims (8)

The first lens group arranged on the object side along the optical axis and
A second lens group arranged on the image side along the optical axis of the first lens group, and
An aperture arranged between the first lens group and the second lens group,
A lens barrel that holds the first lens group, the aperture, and the second lens group.
With
An object-side adjacent lens arranged on the image side of the first lens group and adjacent to the aperture in the optical axis direction, and an object-side adjacent lens arranged on the object side of the second lens group and adjacent to the aperture in the optical axis direction. Of the image-side adjacent lenses, one is a one-sided lens made of glass and the other is a other-side lens made of a resin material, and the lens barrel is made of a resin material different from the other-side lens.
The object-side adjacent lens, the diaphragm, and the image-side adjacent lens are housed in a lens accommodating portion provided in the lens barrel.
The one-sided lens is supported by the lens holder on the outside as seen from the optical axis and is housed in the lens housing.
By engaging with the lens holder, the other-side lens is fixed in the positional relationship between the one-side lens in the optical axis direction and in the direction perpendicular to the optical axis.
A plurality of positioning holes are formed in the diaphragm in the circumferential direction around the optical axis.
On the side of the lens holder facing the diaphragm, a plurality of convex portions protruding toward the side where the diaphragm is located are formed corresponding to the positioning holes.
The diaphragm is a lens unit characterized in that it is mounted on the lens holder in a state where the convex portion is engaged with the positioning hole. The lens unit according to claim 1, wherein the length of the positioning hole along the circumferential direction around the optical axis is made larger than the length of the corresponding convex portion along the circumferential direction. The one-sided lens is the image-side adjacent lens.
In the second lens group, an image side lens adjacent to the image side of the image side adjacent lens is provided.
The lens holder is provided with a plurality of protrusions protruding toward the image side.
The plurality of protrusions are divided into a plurality of protrusion groups according to the amount of protrusion, and the plurality of protrusions belonging to one protrusion group are locked to the image side lens on the image side. The lens unit according to claim 1 or 2, wherein the movement of the image-side adjacent lens to the image side is restricted. The lens holder is formed with a lens built-in hole, which is a hole for accommodating the one-sided lens from the side opposite to the side where the diaphragm is located.
The one-sided lens is fixed to the lens holder in a state of being locked by a lens fixing surface formed by being dispersed in a plurality of directions in the circumferential direction around the optical axis, which is the bottom surface of the lens incorporating hole on the side where the diaphragm is located. ,
The diaphragm is fixed to the lens holder in contact with the diaphragm mounting surface, which is a region other than the convex portion of the lens holder.
Claims 1 to 3 are characterized in that a region of contact with the one-sided lens on the lens fixing surface and a region of contact with the diaphragm on the diaphragm mounting surface overlap with each other when viewed from the optical axis direction. The lens unit according to any one of the above items. The surface of the lens holder opposite to the side with the diaphragm is a groove dug down toward the side with the diaphragm, and the lens incorporating hole is viewed from the side opposite to the side with the diaphragm in the optical axis direction. The lens unit according to claim 4, wherein a plurality of first adhesive grooves to be connected to the lens are dispersed and formed in the circumferential direction around the optical axis. Inside the lens built-in hole, a plurality of ribs that locally project toward the optical axis are formed in the circumferential direction around the optical axis so as to lock the one-sided lens from the outside when viewed from the optical axis.
On the surface of the lens holder on the side where the aperture is located,
It is a groove dug down toward the side opposite to the side with the diaphragm, and a plurality of notches overlapping the rib when viewed from the side with the diaphragm in the optical axis direction are dispersed in the circumferential direction around the optical axis. The lens unit according to claim 5, wherein the lens unit is formed. The lens unit according to claim 6, wherein an adhesive for fixing the one-side lens to the lens holder is stored in the first adhesive groove or the notch. The other side lens and the lens holder are made of amorphous plastic.
The lens barrel is made of crystalline plastic and
The lens unit according to any one of claims 1 to 7, wherein the other side lens is not in contact with the lens barrel.