JP7296826B2 - Lens unit and camera module - Google Patents

Description

The present invention relates to lens units and camera modules.

2. Description of the Related Art In recent years, a vehicle is equipped with a camera, and an image such as a landscape outside the vehicle captured by the vehicle-mounted camera is displayed on a monitor or the like mounted inside the vehicle. In addition, the captured image is used for a parking assist function, an automatic braking function, an automatic driving function, and the like. The lens unit used in this on-vehicle camera is required to have strength, waterproofness, chemical resistance, high-temperature durability, etc., because the side facing the imaging target (object side) is exposed to the outside of the vehicle. In addition, it is necessary to prevent fogging of the lens due to temperature changes.

Patent Literature 1 discloses a lens unit configured to ensure an airtight state inside a lens barrel. In this lens unit, four lenses are arranged side by side along the optical axis in the lens barrel. , sealing is achieved. Further, on the image side (imaging element side), the optical filter is adhered to the lens barrel via an adhesive to achieve sealing. By sealing the object side and the image side in this manner, the airtightness of the inside of the lens barrel is ensured, and fogging of the lens is prevented.

Japanese Patent No. 4999508

By the way, in some lens units as described above, a square concave portion is formed on the image side surface of the lens barrel, and a square optical filter is adhesively fixed to the concave portion. When the optical filter is fixed by adhesion in this way, there is a large variation in the adhesive strength (bonding strength), so there is a problem that it is difficult to quantitatively control the adhesive strength and stabilize the quality. In addition, the bonding strength between the optical filter and the lens barrel may decrease due to changes in the environment (temperature, etc.) in which it is used, which poses a problem in terms of reliability. In particular, when a shock or vibration is applied to the lens unit, the adhesive strength tends to decrease and the optical filter tends to come off or peel off remarkably.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. It is an object of the present invention to provide a lens unit and a camera module with improved productivity and reliability.

In order to solve the above problems, the lens unit of the present invention includes:
A lens unit comprising a resin barrel formed in a cylindrical shape and a plurality of lenses arranged side by side along the axial direction of the barrel inside the barrel,
The lens barrel is
an annular filter placement portion formed on the image-side inner peripheral surface so as to extend radially inward;
a filter holding portion having at least two plate-shaped members extending radially inward at the inner peripheral edge portion of the image-side end surface;
Either a combination of a convex portion and a convex portion or a combination of a convex portion and a stopper portion is formed on the object-side surface of the filter holding portion,
A rectangular optical filter is arranged on the image-side surface of the filter arrangement portion,
Of the four corners of the optical filter, at least two opposing corners are locked between the projections or between the projections and the stopper.

According to such a configuration, the plate-like filter holding portion extending radially inward is provided on the image-side end surface of the lens barrel, and at least two of the four corners of the square optical filter, which are opposite to each other, are provided. The two corners are locked between the projections formed on the object-side surface of the filter holding portion, or between the projections and the stopper portion, so that the optical filter can be rotated in the direction of rotation. Movement is restricted, and axial movement of the optical filter is restricted. As a result, since the optical filter can be fixed to the lens barrel without bonding, there is no need to manage the bonding strength, and the quality is stabilized and the productivity is improved. Moreover, since the adhesive strength does not decrease due to changes in the usage environment, reliability can be improved.

Further, in the configuration of the present invention, the stopper portion has a projection shape having a larger projection amount than the projection portion. Further, in the configuration of the present invention, the stopper portion is a surface perpendicular to the object side surface of the filter holding portion and has a shape having a flat portion for restricting rotation of the optical filter. do.

According to this configuration, the stopper portion has a projection shape with a large amount of projection or a shape having a flat portion that restricts the rotation of the optical filter. It is possible to reliably prevent the optical filter from rotating without stopping when engaging between the projections of the filter holding portion or between the projection and the stopper portion. This improves workability when arranging the optical filter.

Further, in the configuration of the present invention, the filter holding portion has a concave shape at a portion corresponding to the convex portion on at least one of the image-side surfaces, and the convex portion located on the opposite side of the concave shape. The base end portion is positioned closer to the object side than the base surface, which is the object-side surface of the filter holding portion.

According to such a configuration, the base end portion of the convex portion located on the opposite side of the concave shape of the filter holding portion is located closer to the object than the base surface, which is the object-side surface of the filter holding portion. Therefore, the movement of the optical filter in the rotational direction is more reliably restricted, and the movement of the optical filter in the axial direction is more reliably restricted. Thereby, the reliability of fixation of the optical filter can be further improved.

Further, in the configuration of the present invention, the optical filter is adhered to the filter placement portion. According to such a configuration, at least two of the four corners of the square-shaped optical filter, which face each other, are positioned between the convexes formed on the object-side surface of the filter holder. , or is locked between the convex portion and the stopper portion, and the optical filter is additionally adhered to the filter placement portion, so that the optical filter is fixed more firmly. reliability can be further improved.

Further, in the configuration of the present invention, the filter placement portion of the lens barrel is formed with an axially penetrating hole at a position facing the object-side surface of the filter holding portion. do. According to such a configuration, the filter mounting portion has a hole axially penetrating therethrough at a position facing the object side surface of the filter holding portion. Even if a filter holding portion protruding inward is provided, the shape of the lens barrel does not become a so-called undercut shape. Therefore, the lens barrel can be molded with a mold having a simple structure without making the structure of the mold complicated. As a result, the manufacturing cost can be reduced, and the time required for molding is shortened, thereby improving productivity.

A camera module of the present invention is characterized by comprising the lens unit configured as described above, and an imaging device for capturing an image formed by the lens unit. With such a configuration, the camera module can achieve the same effects as the lens unit of the present invention described above.

According to the present invention, there is no need to manage the adhesive strength of the optical filter arranged on the image side of the lens barrel, and the peeling of the optical filter due to a decrease in the adhesive strength does not occur, thereby improving productivity and reliability. can be improved.

1 is an axial sectional view of a lens unit according to an embodiment of the invention; FIG. It is the figure which looked at the lens-barrel from the image side equally. It is a figure which looked at the lens-barrel from the image side similarly, and shows a modification. FIG. 3 is an end view of the same taken along the line AA shown in FIG. 2; Similarly, the lens unit is viewed from the image side, (a) is a diagram showing a state in which the optical filter is placed on the filter placement portion, and (b) is a diagram showing a state in which the optical filter is rotated so that the two corners of the filter It is a figure which shows the state hold|maintained at the holding|maintenance part. Similarly, the lens unit using the lens barrel shown in FIG. 3 is viewed from the image side. It is a figure which shows the state rotated and the four corner|angular parts were hold|maintained at the filter holding|maintenance part. 6 is a schematic cross-sectional view taken along line BB shown in FIG. 5; FIG. FIG. 6 is a schematic cross-sectional view taken along the line BB shown in FIG. 5, showing a modified example of the filter holding portion; FIG. 8A is a view of the lens barrel viewed from the image side, and FIG. 8B is a schematic cross-sectional view taken along line CC shown in FIG. 3A shows a case where a part of the filter holding portion is heat-sealed, FIG. 4A is a view of the lens unit viewed from the image side, and FIG. It is a diagram. FIG. 4 is a view of the lens unit viewed from the image side of the same, and is an explanatory view of an adhesive application location. FIG. 10 is an explanatory diagram showing a mold structure of portions for molding the filter placement portion and the filter holding portion of the lens barrel.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an axial cross-sectional view of a lens unit 100 according to this embodiment. In addition, in FIG. 1, hatching indicating a cross section is omitted. The lens unit 100 includes a lens barrel 10, a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a plurality of diaphragms 6, an optical filter 7, and the like.

In the lens unit 100, an optical filter 7 is arranged at the end on the image side (imaging side) where the first lens 1, the second lens 2, the third lens 3 and the fourth lens 4 form images. Details of the arrangement of the optical filter 7 will be described later. An imaging element (not shown) is arranged at a position facing the optical filter 7 on the image side of the lens unit 100, and this imaging element is imaged by the first lens 1 to the fourth lens 4. Take an image. Further, the lens unit 100 is arranged such that the end on the side opposite to the image side, that is, the end on the object side faces the imaging target. This lens unit 100 forms an image of an object on the image side, and is used, for example, in an on-vehicle camera mounted on an automobile. On-vehicle cameras include, for example, a rear view camera that is mounted on a side mirror of a vehicle and captures an image behind the vehicle. The lens unit 100 is installed in the vehicle with the end on the object side exposed to the outside of the vehicle.

The lens barrel 10 is a cylindrical member made of resin. As the resin, a nylon-based resin reinforced with glass fiber is used. This nylon-based resin is generally a polyamide containing an aliphatic skeleton. This resin has excellent chemical resistance, exhibits excellent toughness, impact resistance, and flexibility, and has a high affinity with composite materials such as glass fiber, making it easy to handle as an engineering plastic. However, since it has a high water absorption rate and expands when it absorbs water, it is preferable to use a polyamide-based resin having a low water absorption rate as much as possible. Therefore, for example, Reny (manufactured by Mitsubishi Engineering-Plastics Co., Ltd.), which is a polyamide resin with reduced water absorption, may be used.

The first lens 1 is a substantially circular lens made of glass, and the second lens 2 to the fourth lens 4 are substantially circular lenses made of glass or resin. The first lens 1 to the fourth lens 4 are arranged inside the lens barrel 10 with their optical axes aligned. The inner peripheral surface of the lens barrel 10 has a diameter (inner diameter) that decreases stepwise from the object side to the image side. In addition, the outer diameters of the substantially circular first to fourth lenses 1 to 4 decrease as the arrangement position goes from the object side to the image side. The outer peripheral surfaces of the first lens 1 to the fourth lens 4 are in contact with the inner peripheral surface of the lens barrel 10, so that they are positioned in a direction orthogonal to the optical axis direction. The inner peripheral surface of the lens barrel 10 is, for example, a dodecagonal polygonal shape.

The diaphragm 6 is an annular member and is made of metal, for example. The diaphragm 6 is arranged inside the lens barrel 10, for example, between lenses. The diaphragm 6 has an aperture diaphragm that limits the amount of transmitted light and determines an F-number, which is an index of brightness, or a light shielding diaphragm that shields light rays that cause ghosts and aberrations.

A supporting portion 11 that protrudes radially inward and has an annular shape when viewed from the axial direction is provided on the image-side inner peripheral surface of the lens barrel 10 . The image-side surface of the outer peripheral portion of the fourth lens 4 is in contact with the supporting portion 11 . The outer peripheral portion of the lens is a portion (flange portion) formed on the outer peripheral side of the effective diameter of the lens. Further, the support portion 11 is provided with an opening having a smaller diameter than the outer diameter of the fourth lens 4 .

A crimped portion 12 is provided at the end of the lens barrel 10 closest to the object side. The crimped portion 12 is formed by crimping after the components are accommodated inside the lens barrel 10 . The inner diameter of this crimped portion 12 is smaller than the outer diameter of the first lens 1 . The inner peripheral surface of the crimped portion 12 is in contact with the outer peripheral portion of the object-side surface of the first lens 1 . The components housed inside the lens barrel 10 are held between the supporting portion 11 and the crimped portion 12 so as to be sandwiched therebetween. Thereby, a gap is not formed between each part.

Although not shown, a diameter-reduced portion having an outer diameter smaller than that of the object-side outer peripheral surface is provided on the image-side outer peripheral surface of the first lens 1, and this diameter-reduced portion and the inner peripheral surface of the lens barrel An O-ring as a sealing member may be arranged between and. This O-ring is made of, for example, rubber so that it can be elastically deformed. The gap is sealed to prevent water, dust, etc. from entering the inside of the lens barrel 10. - 特許庁

The optical filter 7 is a rectangular filter and is arranged for the purpose of removing a specific frequency component. As the optical filter 7, there is an infrared cut filter, for example.

Next, fixing of the optical filter 7 to the lens barrel 10 will be described.
As shown in FIG. 1 , a support portion 11 is provided on the image-side inner peripheral surface of the lens barrel 10 , and this support portion 11 also serves as a filter placement portion 16 . That is, it can be said that the filter placement portion 16 is formed in an annular shape so as to extend radially inward on the image-side inner peripheral surface of the lens barrel 10 . The filter arranging portion 16 is formed so as to be located closer to the object side than the end face 15 closest to the image located on the outer peripheral side. In other words, the image-side end surface 15 is located closer to the image side than the filter placement portion 16 .

A filter holding portion 20 is provided on the end face 15 of the lens barrel 10 on the image side. FIG. 2 is a view of the lens barrel 10 viewed from the image side. In the present embodiment, the filter holders 20 are provided at positions facing each other (symmetrical with respect to the center of the lens barrel 10) on the inner peripheral edge of the image-side end surface 15 of the lens barrel 10. It is composed of two plate-like shapes (members) formed so as to extend inward in the direction. A through-hole 17 is provided through the filter placement portion 16 at a position facing the filter holding portion 20 in the axial direction.

FIG. 3 is a diagram showing a modification of the filter holding portion 20. In this example, the filter holding portion 20 is provided on the edge on the inner peripheral side of the end face 15 at intervals of 90° along the circumferential direction. It is composed of four plate-like shapes (members) extending inward in the direction. Hereinafter, there are cases in which the shape of all two or four locations is referred to as the filter holding portion 20 , and in which the shape of one location is referred to as the filter holding portion 20 . As shown in FIG. 1, the filter holding portion 20 extends toward the image side (imaging element side) from the inner peripheral side edge portion of the end face 15 and is bent at right angles to extend radially inward. It is L-shaped.

4 is an end view taken along line AA shown in FIG. 2. FIG. Among the surfaces of the filter holding portion 20 perpendicular to the axial direction, the object-side surface (lens-side surface) is defined as a base surface 21 . On the base surface 21, two projecting protrusions 22 protruding toward the object side are arranged in parallel. The convex portions 22, 22 are arranged side by side with a predetermined distance in the width direction of the filter holding portion 20 (the direction orthogonal to the straight line connecting the center of the lens barrel 10 and the center portion of the filter holding portion 20). It is This predetermined distance is a distance by which the rotation of the optical filter 7 is restricted when the filter holding portion 20 holds the optical filter 7 . Further, the tips of the projections 22, 22 are R surfaces and have roundness.

Next, a procedure for attaching the optical filter 7 to the lens barrel 10 will be described with reference to FIG.
First, as shown in FIG. 5A, the rectangular optical filter 7 is placed on the filter placement portion 16 while avoiding interference with the filter holding portion 20 .
Next, as shown in FIG. 5B, while the lens barrel 10 is fixed, the rectangular optical filter 7 is rotated clockwise or counterclockwise by 45° so that two opposite corners of the optical filter 7 are rotated. are moved between the protrusions 22, 22 on the filter holding portion 20, respectively. At this time, the two corners of the optical filter 7 move while abutting on the tip of one of the convex portions 22, and when they get over the one convex portion 22, they reach the front of the other convex portion 22 (that is, the one convex portion 22 and the other convex portion 22).

6A and 6B are diagrams illustrating a procedure for attaching the optical filter 7 to the lens barrel 10 when the filter holding portion 20 shown in FIG. 3 is provided.
First, as shown in FIG. 6A, the optical filter 7 is placed on the filter placement section 16 while avoiding interference with the filter holding section 20 .
Next, as shown in FIG. 6B, while being fixed to the lens barrel 10, the rectangular optical filter 7 is rotated clockwise or counterclockwise by 45°, and the four corners of the optical filter 7 are bent. , are moved between the convex portions 22, 22 of the filter holding portion 20, respectively.

FIG. 7 is a schematic cross-sectional view along line BB shown in FIG.
The optical filter 7 has at least two opposing corners locked between the projections 22 , 22 . As a result, movement of the optical filter 7 in the rotational direction (circumferential direction) is restricted, and movement of the optical filter 7 in the axial direction (object side and image side) is restricted. As a result, the optical filter can be fixed to the lens barrel 10 without being adhered, so that there is no need to manage the adhesion strength, and the quality is stabilized and the productivity is improved. Moreover, since the adhesive strength of the optical filter 7 does not decrease due to changes in the usage environment, reliability can be improved.

Next, a modified example (part 1) of the filter holding portion 20 will be described with reference to FIG.
The projecting amounts of the convex portions 22, 22 with respect to the base surface 21 may be different. That is, as shown in FIG. 8, the protrusion amount of one protrusion 22 (referred to as protrusion 22a) may be larger than the protrusion amount of the other protrusion 22 (protrusions 22 arranged side by side). . In this case, the convex portion 22a having a larger amount of protrusion functions as a stopper portion that stops the rotation of the optical filter 7. As shown in FIG. For example, when the convex portion 22a is provided on the right side of each filter holding portion 20 as viewed from the center side of the lens barrel 10, the optical filter 7 is positioned clockwise in one direction from the state shown in FIG. 5(a). When rotated by 45°, the two corners get over the small (short) projection 22 and then come into contact with the large (long) projection 22a and stop. As a result, it is possible to reliably prevent the optical filter 7 from rotating without stopping, and the workability when arranging the optical filter 7 is improved.

Next, a modified example (part 2) of the filter holding portion 20 will be described with reference to FIG. 9 .
9(a) is a view of the lens barrel 10 viewed from the image side, and FIG. 9(b) is a schematic cross-sectional view taken along line CC in FIG. 9(a).
A rib 23 may be provided instead of one projection 22 in the filter holding portion 20 . The rib 23 is formed so as to protrude from the base surface 21 toward the object side, and has, for example, a substantially triangular shape when viewed from the axial direction. The rib 23 may have any shape as long as it has a plane portion 23a that is perpendicular to the base surface 21, faces the adjacent convex portion 22, and restricts the rotation of the optical filter 7. FIG. The plane portion 23a is formed so that an angle formed by a straight line connecting the center portion of the filter holding portion 20 and the center of the lens barrel 10 is approximately 45° when viewed in the axial direction.

The rib 23 functions as a stopper portion that stops the rotation of the optical filter 7 . In this embodiment, the rib 23 is provided on the left side of each filter holder 20 when viewed from the center side of the lens barrel 10 . One corner of the optical filter 7 is accommodated between the flat portion 23 a and the convex portion 22 . When the optical filter 7 is rotated 45 degrees counterclockwise, which is one direction, from the state shown in FIG. It will happen.

Next, in order to further improve the reliability of holding (fixing) the optical filter 7 by the filter holding portion 20, the case where the filter holding portion 20 is thermally welded will be described.
FIG. 10(a) is a view of the lens unit 100 viewed from the image side, and FIG. 10(b) is a schematic sectional view taken along line DD in FIG. 10(a). In the present embodiment, heat welding refers to applying heat and pressure to a part of the resin-made filter holding part 20 to partially deform the shape. In FIG. 10(a), two X portions, that is, portions of the image side surface of the filter holding portion 20 corresponding to one convex portion 22, are thermally welded from the image side toward the object side. there is FIG. 10A shows the case where the portion corresponding to one convex portion 22 in the filter holding portion 20 is thermally welded from the image side. It may be thermally welded from.

As shown in FIG. 10(b), a concave shape 30 is formed at the thermally welded portion. The base end 22b of the convex portion 22 located on the opposite side of the concave shape 30 is positioned closer to the object than the base surface 21 is. That is, as the concave shape 30 is formed, the convex portion 22 moves further toward the object side. As a result, the movement of the optical filter 7 in the rotational direction (circumferential direction) is more reliably restricted, and the movement of the optical filter 7 in the axial direction (object side and image side) is more reliably restricted. Thereby, the reliability of fixation of the optical filter can be further improved.

In the above description, a case where a part of the filter holding portion 20 is heat-sealed has been described, but instead of heat-sealing or in addition to heat-sealing, the optical filter 7 may be adhered to the image-side surface of the filter placement portion 16 . You may In the present embodiment, the optical filter 7 is adhered to the image-side surface of the filter placement portion 16 using, for example, an ultraviolet curable resin, a thermosetting resin, or a thermoplastic resin as an adhesive.
FIG. 11 is a diagram of the lens unit 100 viewed from the image side. The locations where the adhesive is applied are, for example, the four Y portions shown in FIG. By adhesively fixing the optical filter 7 to the filter placement portion 16, the fixing of the optical filter 7 becomes stronger, and the reliability of fixing the optical filter 7 can be further improved.

As shown in FIG. 2 , through holes (holes) 17 are formed in the filter placement portion 16 . The through hole 17 is provided at a position facing the filter holding portion 20 (base surface 21) and has a rectangular shape.
12A and 12B are explanatory diagrams showing a mold structure for forming the filter placement portion 16 and the filter holding portion 20 of the lens barrel 10. FIG. By providing the through hole 17 in the filter placement portion 16, even when the filter holding portion 20 having a shape protruding radially inward is provided on the image side end face 15 of the lens barrel 10, the lens barrel The shape of 10 does not become a so-called undercut shape. That is, the filter holder 20 of the lens barrel 10 can be formed by splitting the mold vertically, for example. Therefore, the lens barrel 10 can be molded with a mold having a simple structure rather than a complicated structure. As a result, the molding time can be shortened, the productivity can be improved, and the manufacturing cost of the lens barrel 10 can be reduced.

Note that the lens unit 100 according to the present embodiment constitutes a camera module together with an imaging element, camera case, substrate, signal processing circuit, flexible wiring sheet, connector (all not shown), and the like.

The camera module works as follows. Light incident from the object side enters the image sensor through the lens group of the lens unit 100 . The imaging device converts an incident image into an electrical signal. The signal processing circuit performs signal processing (A/D conversion, image correction processing, etc.) on the electrical signal from the imaging element. An electrical signal output from the signal processing circuit is output to an external electronic device via the flexible wiring sheet and the connector.

1, 2, 3, 4 Lens 7 Optical filter 10 Lens barrel 15 End face 16 (on the image side of the lens barrel) Filter placement part 17 Through hole (hole)
20 Filter holding portion 22 Convex portion 22a Stopper portion 22b Base end portion 23 Stopper portion 23a Plane portion 30 Concave shape 100 Lens unit

Claims (7)

A lens unit comprising a resin barrel formed in a cylindrical shape and a plurality of lenses arranged side by side along the axial direction of the barrel inside the barrel,
The lens barrel is
an annular filter placement portion formed on the image-side inner peripheral surface so as to extend radially inward;
a filter holding portion having at least two plate-shaped members extending radially inward at the inner peripheral edge portion of the image-side end surface;
Either a combination of a convex portion and a convex portion or a combination of a convex portion and a stopper portion is formed on the object-side surface of the filter holding portion,
A rectangular optical filter is arranged on the image-side surface of the filter arrangement portion,
At least two opposing corners out of four corners of the optical filter are locked between the projections or between the projections and the stopper. lens unit. 2. The lens unit according to claim 1, wherein the stopper portion has a projection shape having a larger amount of projection than the convex portion. 2. The lens unit according to claim 1, wherein the stopper portion is a surface perpendicular to the object-side surface of the filter holding portion and has a shape having a planar portion for restricting rotation of the optical filter. . The filter holding portion has a concave shape at a portion corresponding to the convex portion on at least one of the image side surfaces, and the base end portion of the convex portion located on the opposite side of the concave shape is the filter holding portion. 4. The lens unit according to any one of claims 1 to 3, wherein the lens unit is located closer to the object than the base surface, which is the object-side surface of the lens unit. 5. The lens unit according to any one of claims 1 to 4, wherein the optical filter is adhered to the filter placement portion. 6. An axially penetrating hole is formed in the filter mounting portion of the lens barrel at a position facing the object side surface of the filter holding portion. A lens unit according to any one of the items. A camera module, comprising: the lens unit according to any one of claims 1 to 6; and an imaging device that captures an image formed by the lens unit.

Images