JP2015031926A - Lens unit and camera module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide; a lens unit which allows for preventing fogging due to outgassing of adhesives at low cost when bonding an optical filter in a lens barrel by using adhesives, by providing a communication groove on a bonding surface; and a camera module having the same.SOLUTION: A lens unit includes a lens barrel 1, lenses 2, 3, 4, 6 housed in the lens barrel 1, and an optical filter 7 located at one end of the lens barrel 1. One end surface 22 of the lens barrel 1 has a bonding surface 21 located in an inner area thereof with a step surface 23 between itself and the end surface 22. A circumferential edge portion of the optical filter 7 is bonded to the bonding surface 21. An adhesive recess 25, which has a bottom surface 24 connected to the bonding surface 21 and is for supplying adhesives to be introduced to a space between the bonding surface 21 and the circumferential edge portion of the optical filter 7, is provided at a plurality of locations on the end surface 22. A communication groove 27, which puts the inside of the lens barrel 1 in communication with the outside thereof in a state that the optical filter 7 is bonded to the bonding surface 21, is provided on the bonding surface 21.

Description

  The present invention relates to a lens unit and a camera module that are preferably used for a camera disposed outdoors so that at least a part of the camera is exposed.

  In recent years, since a monitor is mounted on a car for car navigation or the like, for example, as a back monitor system, an image taken by a vehicle-mounted camera mounted on the back of the vehicle is displayed on the monitor. Also, a system has been developed in which this camera is provided not only in the back but also in the front, rear, left, and right sides of the vehicle, and an image overlooking the periphery of the vehicle is synthesized and displayed on a monitor in substantially real time.

Such an in-vehicle camera lens unit is a wide-angle lens unit, and the tip on the object side is out of the vehicle, so strength, waterproofness, chemical resistance, high temperature resistance, etc. are required. Is done. In addition, it is necessary to prevent the lens from fogging with respect to temperature changes.
For example, a lens unit for an in-vehicle camera having a sealed structure for preventing the lens from fogging has been proposed (see, for example, Patent Document 1).

  In this lens unit, as a group of lenses in a cylindrical barrel, for example, four lenses are arranged substantially in the optical axis direction in the barrel, and the gap between the most object side lens and the barrel is Sealed by an O-ring as a sealing material. Further, on the most image side (image sensor side), the optical filter or the lens disposed on the most image side and the lens barrel are fixed with an adhesive, so that the cured adhesive functions as a sealing material.

  Accordingly, the inside of the lens barrel is hermetically sealed by the object-side seal and the image-side seal of the lens barrel, and the occurrence of fogging of the lens in the lens barrel due to a temperature change is prevented. The filter is, for example, an optical filter that cuts light in a predetermined wavelength range, and the filter exemplified in Patent Document 1 is an infrared cut filter. In general digital cameras, the image sensor has sensitivity not only to visible light but also to infrared rays, so it is possible to reduce noise and suppress the redness of the image by placing an infrared cut filter. I do.

Japanese Patent No. 4999508

  By the way, it is known that outgas is generated from the adhesive, and when the structure is finally sealed with the adhesive as described above, there is no escape space from the inside of the lens barrel for the outgas released from the adhesive to be cured. For example, the infrared cut filter may be clouded by outgas.

  In Patent Document 1 described above, a communication path used for inspecting the airtight state inside the lens barrel is provided. The communication path is formed as a hole penetrating between the inner peripheral surface and the outer peripheral surface of the lens barrel so as to communicate between the sealed lens barrel interior and the exterior of the lens barrel. The communication path is closed after the airtight state is inspected. In this case, since the communication path is maintained for a while while penetrating the inside and outside of the lens barrel, there is a possibility that outgas may come out from the communication path, and fogging due to the outgas of the infrared cut filter may be prevented.

  However, since the communication path is provided through the inner peripheral surface from the outer peripheral surface to the central portion of the cylindrical lens barrel, the manufacturing becomes complicated and the manufacturing cost of the lens barrel may increase. For example, when a lens barrel is manufactured by resin molding, the structure of the mold becomes complicated, and mechanical accuracy such as roundness and coaxiality is lowered during molding. This increases the manufacturing cost. Moreover, when providing a through-hole after shaping | molding, a manufacturing process will increase and cost will increase.

  In addition, the work of attaching an optical filter such as an infrared cut filter to the attachment part at the end on the image side (imaging device side) of the lens barrel is costly for the work of applying an adhesive or attaching the filter. In addition, when manufacturing the lens barrel by, for example, injection molding, it is necessary to consider the processing of gate marks and the like. For example, if the gate mark is cut in order to prevent the gate mark from protruding to the image sensor side, the manufacturing process of the lens barrel increases and the cost increases. In addition, when fiber reinforced resin such as glass fiber reinforced resin is used for the lens barrel in order to give the strength required for an in-vehicle camera as described above, fiber fragments fall from the gate traces that cut the gate. If it is on the image sensor side, the fiber fragments may adversely affect the photographing. In particular, there is a tendency for image sensors to have higher resolutions, and when the image sensors of in-vehicle cameras are successively increased in resolution, there is a possibility that the influence of fiber fragments may become serious.

  The present invention has been made in view of the above circumstances, and at the time of bonding an optical filter to a lens barrel with an adhesive, by providing a communication groove on the bonding surface, prevention of fogging due to the outgas of the adhesive can be made at low cost. It is an object to provide a lens unit and a camera module that can be performed.

The lens unit of the present invention includes a lens barrel, a plurality of lenses provided inside the lens barrel along the axial direction of the lens barrel, and an optical filter disposed at one end of the lens barrel. A lens unit in which a space between the outer peripheral surface of the lens and the inner peripheral surface of the lens barrel that is disposed on the other end side of the lens barrel is sealed;
An annular adhesive surface closer to the other end than the end surface is provided inside the annular end surface of the one end of the lens barrel via a step between the end surface,
The peripheral portion of the optical filter is bonded to this bonding surface,
A plurality of locations on the end surface are provided with a bottom surface connected to the adhesive surface, and a recess into which the adhesive is placed to allow an adhesive to enter between the adhesive surface and the peripheral edge of the optical filter. ,
The bonding surface is provided with a communication groove that allows communication between the inside and the outside of the lens barrel in a state where the filter is bonded.

  According to such a configuration, for example, the optical filter is attached to the lens barrel so that the annular adhesive surface and the annular peripheral edge of the optical filter overlap in a state where the lens barrel stands with one end facing up. And the adhesive is put into the concave portion, so that the liquid adhesive enters the narrow gap between the peripheral edge of the optical filter and the adhesive surface by capillary action. As a result, the optical filter can be easily bonded to the lens barrel, and if an appropriate amount of adhesive is injected into the recess, the lens barrel and the optical filter are bonded to each other, thereby facilitating the bonding operation.

  Also, with the lens and lens barrel on the other end side sealed, one end is bonded by bonding the annular peripheral edge of the optical filter to the annular bonding surface inside the end face on one end. It is possible to prevent the inside of the lens tube from being sealed by the agent and to prevent the outgas escape from the adhesive from being lost by the communication groove. That is, even if an optical filter is attached to one end of the lens barrel, outgas can be discharged to the outside through the communication groove. In addition, when the communication groove is closed later, it is preferable to close the communication groove after an elapse of time from the adhesion of the optical filter to the outgas.

  In addition, since the communication groove is provided on the bonding surface of one end of the lens barrel, the mold becomes complicated even if the communication groove is provided at the time of resin molding, compared to the case where the through hole is provided in the lens barrel. In addition, the lens barrel can be formed at low cost without impairing the forming accuracy such as roundness and coaxiality.

  Here, when applying the optical filter after applying the adhesive to the adhesive surface, depending on the cross-sectional area and cross-sectional shape of the communication groove when the adhesive is applied to the adhesive surface, the communication groove is an adhesive. The possibility of being buried is high, and the outgas cannot be released after the optical filter is bonded.

  In addition, if the cross-sectional area of the communication groove is increased, the communication groove will not be filled with the adhesive, but if a communication groove with a large cross-sectional area is provided, the communication groove is surely provided to prevent fogging due to temperature changes. Need to be blocked.

  On the other hand, when the adhesive is spread by capillarity between the adhesive surface and the peripheral edge portion of the optical filter from the concave portion as described above, the distance between the optical filter and the adhesive surface at the communicating groove portion is As a result, the spread of the adhesive liquid stops, the adhesive does not flow into the communication groove, and the communication groove is not filled with the adhesive.

  Depending on the combination of the wettability of the adhesive surface, the cross-sectional area and cross-sectional shape of the communication groove, and the liquid property such as the viscosity of the adhesive, the adhesive may flow into the communication groove. It is preferable to confirm that the adhesive does not flow into the communication groove and fill the communication groove. Moreover, it is preferable to arrange | position a communicating groove in the position as far as possible from the some said recessed part along the circumferential direction of a cyclic | annular adhesive surface as a structure where an adhesive agent does not flow into a communicating groove easily. For example, when a plurality of concave portions are arranged at equal intervals along the circumferential direction, it is preferable that the communication groove is arranged at the center between two adjacent concave portions.

  In this case, even if the cross-sectional area of the communication groove is reduced to some extent, the communication groove is not buried in the adhesive, so the outgas of the adhesive generated in the lens barrel is pushed out from the communication groove near the generation site. However, since the cross-sectional area of the communication groove is small, the movement of air inside and outside the lens barrel is suppressed. It is highly possible to prevent fogging of the water. Therefore, it is possible to reduce the manufacturing cost of the lens unit by adopting a configuration in which the communication groove is not closed.

  Moreover, it is preferable that there is no level | step difference between the bottom face of the recessed part connected to an adhesion surface, and an adhesion surface, and it is preferable that it is the same plane as an adhesion surface, ie, is flush | level. If the adhesive can smoothly enter between the adhesive surface and the peripheral edge of the optical filter when the adhesive is injected into the concave portion, it can be interposed between the adhesive surface and the bottom surface of the concave portion. There may be some steps or slopes.

  In the above configuration of the present invention, it is preferable that the lens barrel is provided by resin molding, and a gate mark formed by separating the gate at the time of the resin molding is disposed in at least a part of the recess.

  According to such a configuration, when a cylindrical lens barrel is manufactured by resin molding such as injection molding, when the gate is cut off after molding, the gate on the product side (lens barrel body side) molded from the gate is used. As long as it is not cut off, gate marks will remain. Note that the manufacturing cost increases when the gate is completely cut off.

  By disposing the gate trace in the recess, it is possible to prevent the gate trace from protruding from the end face of one end of the lens barrel if the gate trace is shorter than the depth of the recess. For example, when one end of the lens barrel is mounted on a mounter provided with an image sensor, it is possible to prevent the gate trace from becoming an obstacle. Therefore, it is not necessary to completely separate the gate from the lens barrel, and the manufacturing cost can be reduced.

  Further, in the above configuration of the present invention, the lens barrel is provided by resin molding, and apart from the recess, there is a gate trace recess in which a gate trace formed by separating the gate at the time of the resin molding is arranged. It is preferable to be provided.

  According to such a configuration, the recess for the gate trace is formed separately from the recess for injecting the adhesive. However, since the recess is formed at the time of molding, the manufacturing cost of the lens barrel does not increase. In addition, since it is not necessary for the concave part for gate traces to put an adhesive agent between an adhesive surface and an optical filter, for example, the adhesive surface and the bottom surface do not need to be connected flush.

  Moreover, the said structure of this invention WHEREIN: It is preferable that the adhesive agent is put into the said recessed part for gate traces.

  According to such a configuration, it is possible to prevent the resin additive and dust from dropping from the gate mark by curing the adhesive. Further, when a fiber reinforced resin such as a glass fiber reinforced resin is used as the resin, it is possible to prevent the fiber fragments from dropping from the gate trace. In this case, it is possible to prevent the fiber fragment or the like from entering a certain part of the mounter side, particularly the image pickup device, and causing a stain or a shadow to appear in the image, thereby adversely affecting photographing.

  Moreover, the said structure of this invention WHEREIN: It is preferable that the obstruction | occlusion member which plugs up this communication groove is provided in the said communication groove.

  According to such a configuration, after the outgas inside the lens barrel is discharged by the communication groove, the inside of the lens barrel is made airtight by closing the communication groove, and moisture or the like is deposited inside the lens barrel due to a temperature difference or the like. Thus, it is possible to more reliably prevent the lens in the lens barrel from being fogged. In addition, by replacing the air inside the lens barrel with nitrogen before closing the communication groove to make it oxygen-free, the internal lens when exposed to a high temperature environment of 100 ° C. or higher for a long time. In the case where a resin lens is used, it is possible to prevent the resin lens from being oxidized by oxygen and causing deterioration such as yellowing.

  The camera module of the present invention includes the lens unit having the above-described configuration, and further includes an imaging element that captures an image formed by the lens unit.

  According to such a configuration, the camera module can achieve the same effects as any one of the lens units described above.

  According to the present invention, the gas is sealed at the other end side of the lens barrel, and the optical filter is adhered with an adhesive at one end side so that the lens barrel is closed. In order to discharge the gas, a communication groove that communicates with the inside and outside of the lens barrel is provided on the bonding surface to which the optical filter is bonded. Therefore, the structure in which the outgas in the lens barrel is discharged at low cost can be obtained. In addition, since the adhesive spreads from the concave portion between the adhesive surface and the optical filter by capillary action, it is possible to prevent the adhesive for adhering the optical filter from flowing into the communication groove.

It is sectional drawing which shows the lens unit of embodiment of this invention. It is a principal part perspective view which shows the said lens unit before attaching an optical filter. It is a perspective view which shows the said lens unit before attaching an optical filter. It is a principal part perspective view which shows the said lens unit. It is a perspective view which shows the said lens unit. It is principal part sectional drawing which shows the said lens unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1 to FIG. 6, the lens unit of this embodiment includes a lens barrel 1, a plurality (four) of lenses 2, 3, 4, 6 arranged in the lens barrel 1, and a lens barrel An optical filter 7 disposed at one end on the (imaging) side (the side on which the image sensor is disposed) where the one lens 2, 3, 4, 6 connects the image, and the most object side of the lens barrel 1. An O-ring 8 as a seal member, a diaphragm member 9, and a spacer (intermediate ring) 5 are provided between the outer peripheral surface of the lens 2 and the inner peripheral surface of the lens barrel 1.

This lens unit is, for example, a wide-angle lens unit used in an in-vehicle camera that is disposed in a state where at least the object-side lens 2 is exposed to the outside of the automobile in order to photograph the back side of the automobile or the surroundings of the automobile. It is.
The lens barrel 1 is made of a nylon resin reinforced with glass fibers. This nylon resin is generally a polyamide containing an aliphatic skeleton. This resin is excellent in chemical resistance, exhibits excellent toughness, impact resistance, and flexibility, and has high affinity with a composite material such as glass fiber and can be handled 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 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.

  In addition, the lens barrel 1 has four lenses 2, 3, 4, and 6 that constitute one lens group arranged side by side along the axial direction of the lens barrel 1. Further, the optical axis directions of the lenses 2, 3, 4, and 6 are arranged so as to substantially coincide with the axial direction of the lens barrel 1. One end of the lens barrel 1 is disposed on the imaging side as the imaging side, and the other end is disposed on the object side toward the photographing target.

  The lenses 2, 3, 4, 6, the diaphragm member 9, and the spacer 5 are inserted and installed in order from the object side to the imaging side with respect to the lens barrel 1. A diaphragm member 9 is disposed between the second lens 3 and the third lens 4 from the object side, and a spacer 5 is disposed between the third lens 4 and the fourth lens 6 from the object side. ing. When the lenses 2, 3, 4, and 6 are installed in the lens barrel 1, the lenses 2, 3, 4, and 6, the aperture member 9, and the spacer 5 are placed on the object side in the lens barrel 1 in this order from the imaging side. Insert from the end of the.

  Further, the diameters of the lenses 2, 3, 4, 6 and the spacer 5 are reduced in the order of arrangement from the object side to the imaging side. On the other hand, a plurality of (five) installation portions 11 to 15 having different diameters are provided on the inner peripheral side of the lens barrel 1. The installation units 11, 12, 13, and 15 are the lens installation units 11, 12, 13, and 15 for the lenses 2, 3, 4, and 6, and the installation unit 14 is the installation unit for the spacer 5.

  Each of the installation portions 11 to 15 has an inner diameter that decreases from the object side to the imaging side of the lens barrel 1. Corresponding to the fact that the second lens 3 from the object side consists of a large-diameter portion on the object side and a small-diameter portion on the imaging side, the installation portion 12 on which the lens 3 is installed has a large-diameter portion and It consists of a small inner diameter part.

Moreover, the inner peripheral surface of the installation part 11 closest to the object has a cylindrical shape, but the other installation parts 12 to 15 have an inner peripheral surface of an octagonal or more polygonal cylindrical shape. In addition, the installation part 14 of the spacer 5 may have a circular or polygonal inner peripheral surface.
In addition, each installation portion 12 to 15 is provided with a lens introduction portion having an enlarged inner diameter at the end on the object side where the lenses 3 to 6 are inserted, and the imaging side thereby has a cylindrical shape with a constant inner diameter. It has become.

  Further, the object-side installation portion 11 has an end portion on the object side serving as a heat caulking portion 17, and after the four lenses 2, 3, 4, and 6 are installed in the lens barrel 1, the heat caulking portion is provided. Since the lens 17 is crimped by applying heat, the lenses 2, 3, 4 and 6 are accommodated so as not to come out of the opening on the object side end of the lens barrel 1 and pressed to the image forming side. It is attached.

  Further, at the opening of the end portion on the image forming side of the lens barrel 1, an annular plate-shaped reduced diameter portion 18 is adjacent to the image forming side of the installation portion 15 closest to the image forming side of the lens barrel 1. The inner diameter of this portion is narrower than the outer diameter of the lens 6 on the most image-forming side, and the lens 6 on the most image-forming side has a reduced diameter portion 18. Thus, the lens barrel 1 is supported so as not to come out from the end portion on the image forming side of the lens barrel 1. Therefore, the four lenses 2, 3, 4, and 6 are supported on the inner side of the lens barrel 1 so as not to move between the reduced diameter portion 18 and the heat caulking portion 17.

  Further, the above-described O-ring 8 is disposed between the inner peripheral surface of the installation portion 11 closest to the object side of the lens barrel 1 and the small diameter portion where the diameter of the outer peripheral surface of the lens 2 closest to the object side is reduced. . The O-ring 8 seals between the inner peripheral surface of the lens barrel 1 and the outer peripheral surface of the lens 2 closest to the object side at the object side end of the lens barrel 1.

  A flange portion 19 having the largest outer diameter in the lens barrel 1 is provided slightly closer to the imaging side than the heat caulking portion 17 provided at the object side end of the lens barrel 1. The flange portion 19 is formed in a bowl shape protruding outward, an O-ring (not shown) is disposed on the object side, and an inner peripheral surface of a cylindrical case (not shown) that is placed on the lens barrel 1 and the lens barrel 1. The outer peripheral surface is sealed to prevent water from entering between the lens barrel 1 and the case to the mounter side where the lens barrel 1 is fixed.

  Further, a male screw portion 20 is formed adjacent to the image forming side of the flange portion 19 of the lens barrel 1. The male screw portion 20 is for screwing into a female screw portion (not shown) provided with an image pickup device to fix the lens barrel 1 to the mounter. It should be noted that by adjusting the axial position of the lens barrel 1 when the male screw portion 20 is screwed, focusing can be performed during the manufacture of the in-vehicle camera. A set number of recesses for rotating the lens barrel 1 with a jig when the lens barrel 1 is screwed to the mounter are arranged at equal intervals on the outer peripheral surface of the flange portion 19.

  An adhesion surface 21 for adhering the optical filter 7 to the above-described reduced diameter portion 18 is provided at the image forming end of the lens barrel 1. The structure of the end portions of the lens barrel 1 such as the end surface 22 on the image forming side and the bonding surface 21 will be described in detail later.

  Of the lenses 2, 3, 4, and 6 for calibrating a series of lens groups, the lens 2 on the most object side is made of glass and is more resistant to scratches and heat than a resin lens. Further, the lens 2 has a smaller outer diameter on the image forming side than on the object side, and the O-ring 8 described above is arranged in a small diameter portion where the outer diameter is small.

  Except for the lens 2, the second to fifth lenses 3 to 6 in the order from the object side are resin lenses, and are made of, for example, an amorphous polyolefin resin, a polycarbonate resin, or the like, and are manufactured by injection molding. . In addition, the gate marks 3a, 4a and 6a remain on the outer peripheral surfaces of the lenses 3, 4 and 6.

The optical filter 7 is, for example, a multilayer film deposited on glass for the purpose of removing a specific frequency component of outside light. In this embodiment, the optical filter 7 is an infrared cut filter (infrared removal filter). ).
The optical filter 7 is not limited to the infrared cut filter as long as it removes a specific frequency component as described above.

  For example, the optical filter 7 transmits light in the visible light band, blocks light in the first near infrared band adjacent to the visible light band, and further has a second wavelength longer than the first near infrared band. An optical filter that transmits light in the near-infrared band may be used. According to this optical filter, the second near-infrared wavelength band is adjusted to the output wavelength (for example, 880 nm) of the infrared illumination that is used auxiliary during night photography, so that the second near-infrared wavelength band can be Light in the infrared band excluding the infrared band is blocked and good shooting is possible, and shooting at night is possible with infrared illumination light using the second near-infrared band that passes through the optical filter. .

  As described above, the O-ring 8 is a seal member that seals between the cylindrical outer peripheral surface of the lens 2 closest to the object side and the cylindrical inner peripheral surface of the installation portion 11 closest to the object side of the lens barrel 1. is there. The material of the O-ring 8 is, for example, NBR (nitrile rubber), EPDM (ethylene propylene rubber), FKM (fluorine rubber), CR (chloroprene rubber), VMQ (silicone rubber), UR (polyurethane rubber), NR ( Natural rubber), ACM (acrylic rubber) and the like can be suitably used.

  The diaphragm member 9 is an annular light shielding sheet, and is fixed by the adjacent lens 3 and lens 4 to limit the range of passing light. Main materials of the diaphragm member 9 are, for example, a plastic material such as PET (stretched polyester) and carbon black. The reduced diameter portion 18 may have a function similar to that of the aperture member 9.

  The spacer 5 functions as a light amount diaphragm, and controls the amount of light passing therethrough to determine the F value as a lens unit. The principal ray passes through the center of the spacer 5, and the object side and the image (imaging) side. It plays the role of a conjugate point where the light beam inverts at the stop. The light beam passing through the spacer 5 is most focused. Further, the spacer 5 is configured to maintain a predetermined distance between the lens 4 and the lens 6 in the optical axis direction as a spacer. The spacer 5 can be made of, for example, black polycarbonate that blocks light.

  Such a lens unit includes the above-described imaging device, and is configured to constitute a camera module in combination with a mounter to which the lens barrel 1 is screwed and the above-described case covering the outer periphery of the lens barrel 1. The camera module is attached to the vehicle and wired.

Next, the structure of the end portion (one end portion) including the image-side end surface 22 and the adhesive surface 21 to which the optical filter 7 of the lens barrel 1 is attached will be described.
At the end of the lens barrel 1 on the image forming side, a reduced diameter portion 18 is formed so as to protrude inward. The outer peripheral side of the reduced diameter portion 18 is integrally joined to the inner peripheral surface of the lens barrel 1, and the inner peripheral side has a shape in which a circular opening is provided in the central portion of the plate body. That is, the reduced diameter portion 18 is annular and plate-shaped.

  The side surface on the object side of the reduced diameter portion 18 is a flat surface and is in contact with the contact surface of the outer peripheral portion of the lens 6 on the most imaging side so as to receive the lens 6. Further, the side surface on the imaging side of the reduced diameter portion 18 is a bonding surface 21 to which the outer peripheral edge and the inner peripheral edge are circular planes and the peripheral edge of the disk-shaped optical filter 7 is bonded. .

  An adhesive surface 21 is disposed adjacent to the inside of the end surface 2 that is the surface closest to the image formation side of the lens barrel 1, and the adhesive surface 21 has a shape that is drawn one step closer to the object side than the end surface 22. A step surface 23 is provided in a circular shape between the adhesive surface 21 and the end surface 22. That is, the end face 22 is provided around the adhesive face 21 so as to protrude in the axial direction of the lens barrel 1.

The end face 22 is provided with an adhesive recess 25 for supplying an adhesive between the adhesive face 21 and the peripheral edge of the optical filter 7 so that the bottom face 24 is connected to the adhesive face 21.
The recess 25 is formed in a substantially semicircular shape or an arc shape smaller than the semicircle on the inner peripheral side of the end surface 22, and opens to a step surface 23 between the adhesive surface 21 and the end surface 22. As a result, the bottom surface 24 of the recess 25 and the adhesive surface 21 are connected. Further, the bottom surface 24 and the adhesive surface 21 are arranged in the same plane.

  A plurality (three) of the adhesive recesses 25 are provided at equal intervals along the circumferential direction on the inner peripheral portion of the end surface 22 in which the outer peripheral edge and the inner peripheral edge are coaxially arranged.

  The concave portion 25 for adhesive is used to supply the adhesive between the adhesive surface 21 and the optical filter 7 when the peripheral portion of the optical filter 7 is bonded to the adhesive surface 21. For example, the optical filter 7 is placed on the adhesive surface 21 with the lens barrel 1 standing with the adhesive surface 21 facing up, and the adhesive is recessed with the adhesive surface 21 and the peripheral edge of the optical filter 7 overlapped. 25, for example, the adhesive that has entered the recess 25 enters and spreads between the optical filter 7 and the adhesive surface 21 from the outer edge of the optical filter 7 by capillary action, and the peripheral surface of the adhesive surface 21 and the optical filter 7 Adhesive will spread throughout.

  The adhesive is, for example, an ultraviolet curable resin and spreads smoothly between the adhesive surface 21 and the optical filter 7 by the capillary phenomenon as described above, and does not flow into the communication groove 27 described later. The viscosity is preferably 1000 to 3000 mPa · S. Note that the adhesive is not limited to the ultraviolet curable resin, and may be a thermosetting resin or other resin. However, the ultraviolet curable resin is cured in a short time by being irradiated with ultraviolet rays, so that it can be handled. Easy.

  The circular bonding surface 21 whose outer peripheral edge and inner peripheral edge are coaxial is provided with a communication groove 27 along the radial direction of the bonding surface 21 from the inner peripheral edge to the outer peripheral edge. The communication groove 27 has an inner end that opens to the inner peripheral surface of the lens barrel 1 and communicates with the inner side of the lens barrel 1, and an outer end that is bent at a right angle by the step surface 23. It extends along the surface 23 and communicates with the outside of the lens barrel 1 at this portion.

The outside position of the communication groove 27 is a position where a later-described gate mark recess 30 is disposed,
The communication groove 27 extending to the step surface 23 opens to the bottom surface 31 of the gate mark recess 30.
Therefore, as shown in FIG. 6, the communication groove 27 opens to the inner peripheral surface of the lens barrel 1 and the end surface portion outside the optical filter 7 of the lens barrel 1 at the position of the inner side surface of the optical filter 7. As described above, in the lens barrel 1 in which the object side is sealed with the O-ring 8 and the optical filter 7 is adhered and sealed (sealed) on the imaging side with the adhesive, It communicates with the outside.
The communication groove 27 is provided substantially at the center between two adjacent adhesive recesses 25 among the adhesive recesses 25 arranged at equal intervals along the circumferential direction of the end face 22.

Further, the end face 22 of the lens barrel 1 is provided with a gate mark recess 30 in which a gate mark 32 (shown in FIG. 1) generated when the lens barrel 1 is molded with resin. The gate mark recess 30 is substantially circular and is open to the end surface 22, and is open to the step surface 23 on the inner periphery of the end surface 22. The gate mark 32 is shown in FIGS. 1 and 2 and is not shown in other drawings.
In addition, the bottom surface 31 of the gate mark recess 30 is located closer to the adhesive surface 21 than the end surface 22 between the end surface 22 and the adhesive surface 21 in the axial direction of the lens barrel 1.

  Accordingly, there is a step between the bottom surface 31 of the gate mark recess 30 and the bonding surface 21. Further, as shown in FIG. 1, there is a gate mark 32 that is separated from the bottom surface 31 of the gate mark recess 30 when the lens barrel 1 is formed, but the height of the gate mark 32 (in the axial direction of the lens barrel 1). The length along the axial direction of the lens barrel 1), and the gate trace recess so that the gate trace 32 does not protrude outward from the gate trace recess 30. A depth of 30 is set.

  The gate is called a pin gate designed to be cut naturally when the lens barrel 1 is released, and is not cut by post-processing such as cutting. Thereby, there is a possibility that a piece of fiber such as glass fiber may fall from the gate mark 32, and an adhesive is applied to the gate mark portion of the recess 30 for the gate mark. That is, an adhesive is put in the recess 30 for gate traces. Thereby, it will be in the state where the fiber fragment exposed in the gate trace 32 part was hardened so that it might not fall with adhesives. This adhesive is, for example, an ultraviolet curable resin, and preferably has a viscosity of 5000 mPa · S or more. The adhesive is not limited to the ultraviolet curable resin, but may be a thermosetting resin or other resin, but the ultraviolet curable resin is easier to handle as described above.

  A plurality (three) of gate trace recesses 30 are arranged at equal intervals along the circumferential direction of the end face 22. Further, in this embodiment, the same number of the recesses for gate traces 30 and the recesses for adhesive 25 are provided, and the recesses for gate traces 30 and the recesses for adhesive 25 are alternately arranged at equal intervals. Yes. Therefore, since the gate mark recess 30 is arranged at the approximate center between the two adhesive recesses 25 adjacent in the circumferential direction, the communication groove 27 at the center between the two adhesive recesses 25 adjacent to each other. Similarly, the gate trace recess 30 at the center between the two adjacent adhesive recesses 25 partially overlaps.

Next, a method for attaching the optical filter 7 to the lens barrel 1 in such a lens unit will be described.
In the lens barrel 1 to which the lenses 2, 3, 4, and 6 are attached, the lens barrel 1 is set up with the bonding surface 21, that is, one end on the imaging side facing up. Next, the optical filter 7 is disposed on the adhesive surface 21 inside the end surface 22. At this time, the optical filter 7 is placed on the adhesive surface 21 in a state where the outer peripheral edge of the optical filter 7 is guided by the stepped surface 23, so that the optical filter 7 is positioned on the adhesive surface 21. Placed on. Note that the inner diameter of the cylindrical step surface 23 is slightly larger than the outer diameter of the disk-shaped optical filter 7.

  Next, an adhesive is dripped at each of the three concave portions 25 for adhesive. The dropped adhesive travels along the bottom surface 24 of the adhesive recess 25 and enters between the adhesive surface 21 and the optical filter 7 by capillary action and spreads between them. At this time, the adhesive expanded from the three adhesive recesses 25 comes into contact with the adhesive expanding from the adjacent adhesive recess 25 to become an integral adhesive, and the adhesive surface 21 and the optical filter 7 are bonded. It will be in the state extended to the substantially whole between the peripheral part which overlaps with the surface 21. FIG. As a result, the optical filter 7 is bonded to the bonding surface and is sealed with an adhesive except for the portion of the communication groove 27.

  In the communication groove 27 portion, the adhesive spreads as described above from the adhesive concave portions 25 on both the left and right sides of the communication groove 27, but the spread of the adhesive stops at the communication groove 27 portion. That is, when the adhesive spreading from the left and right sides of the communication groove 27 reaches the left and right edges of the communication groove 27, the distance between the optical filter 7 and the bonding surface 21 is widened at the portion of the communication groove 27. The spread of the agent stops. Accordingly, the adhesive can be put up to the left and right side edges of the communication groove 27, and the adhesive does not flow into the communication groove 27, and the inside and outside of the lens barrel 1 can be communicated with each other at the communication groove 27.

  The communication between the inside and outside of the lens barrel 1 by the communication groove 27 enables the outgas generated from the adhesive for applying the optical filter 7 to be discharged. Thereby, it is possible to prevent the optical filter 7 and the lenses 2, 3, 4, and 6 from being fogged by outgassing.

Further, when the inside of the lens barrel 1 is completely sealed, the closing member is put into the communication groove 27 after the outgas is exhausted to some extent. As the closing member, for example, an adhesive can be used, and in particular, an adhesive made of an ultraviolet curable resin can be suitably used. Further, the cross-sectional area of the communication groove 27 is preferably about 0.4 mm × 0.3 mm (0.12 mm ² ), for example, and is not so large, and even if the communication groove 27 is not completely closed, it is practically usable. There is a high possibility that it can be used at a satisfactory level.

  In such a lens unit, as described above, by sticking the optical filter 7 to one end of the lens barrel 1 with an adhesive, the outgas of the adhesive escapes when the inside of the lens barrel 1 is made a sealed structure. The communication groove 27 can prevent the optical filter 7 and the like from being fogged by remaining in the lens barrel 1. In this case, the communication groove 27 is formed on the bonding surface 21 disposed adjacent to the inner side of the end surface 22 of the lens barrel 1, and on the image forming side of the bonding surface 21 on the inner side of the end surface 22, Even if there is no member and grooves are formed on the adhesive surface during molding, the mold structure for resin molding is prevented from becoming complicated, and mechanical accuracy such as roundness and coaxiality is also achieved in molding. It can be prevented from decreasing.

Accordingly, even if the communication groove 27 is provided as a communication path that communicates the inside and outside of the lens barrel 1, an increase in cost can be suppressed.
Further, when the optical filter 7 is bonded to the bonding surface 21, an adhesive is applied between the bonding surface 21 and the optical filter 7 by a capillary phenomenon from the adhesive recess 25 having the bottom surface 24 connected to the bonding surface 21. Since the configuration expands, it is possible to prevent the communication groove 27 from clogging due to the adhesive flowing into the communication groove 27 during bonding.

  That is, even if the communication groove 27 is formed on the bonding surface 21, if the adhesive applied to the bonding surface 21 flows into the communication groove 27 and the communication groove 27 is filled, the inside and outside of the lens barrel 1 cannot be communicated. Therefore, as described above, as a configuration in which the adhesive is spread between the adhesive surface 21 and the optical filter 7 by capillary action, the surface on the adhesive side of the optical filter 7 and the adhesive surface 21 ( By separating the bottom surface of the communication groove 27 (increasing the distance), the capillary phenomenon does not occur, and the spread of the adhesive is stopped. Internal and external communication can be secured.

  Further, when the lens barrel 1 is molded, gates are provided at a plurality of locations on the end surface 22 of the lens barrel 1 and resin is injected from the plurality of gates into the cavity for molding the lens barrel 1. Since the gate mark 32 when the gate is cut is arranged in the gate mark recess 30, it is possible to prevent the gate mark 32 from protruding from the end face 22 to the image forming side.

  Further, by injecting an adhesive into the gate mark recess 30 and hardening the gate mark 32 with the adhesive, a glass fiber fragment is prevented from dropping from the gate mark 32 to the mounter to which the lens barrel 1 is attached. it can. Thereby, for example, it is possible to prevent a glass fiber fragment from falling on the surface of the image pickup device and appearing as a spot or shadow in the photographed image and adversely affecting the photographing.

  In this embodiment, the concave portion for adhesive 25 and the concave portion for gate trace 30 are provided separately, but by configuring the gate trace 32 on the bottom surface of the concave portion for adhesive 25, The adhesive recess 25 and the gate trace recess 30 may be one type of recess. For example, in the above-described embodiment, three adhesive recesses 25 are provided and six recesses 30 are provided by providing three gate trace recesses 30. However, these recesses are also used as three recesses. It is good also as a structure which provides only one.

1 Lens barrel 2, 3, 4, 6 Lens 7 Optical filter 21 Adhesive surface 22 End surface 23 Step surface (step)
24 Bottom 25 Recess for adhesive (recess)
27 Communication groove 30 Recess for gate mark 32 Gate mark

Claims (6)

A lens barrel; a plurality of lenses provided inside the lens barrel along the axial direction of the lens barrel; and an optical filter disposed at one end of the lens barrel; A lens unit in which a gap between the outer peripheral surface of the lens and the inner peripheral surface of the lens barrel disposed on the end side of the lens unit is sealed,
An annular adhesive surface closer to the other end than the end surface is provided inside the annular end surface of the one end of the lens barrel via a step between the end surface,
The peripheral portion of the optical filter is bonded to this bonding surface,
A plurality of locations on the end surface are provided with a bottom surface connected to the adhesive surface, and a recess into which the adhesive is placed to allow an adhesive to enter between the adhesive surface and the peripheral edge of the optical filter. ,
The lens unit according to claim 1, wherein a communication groove is provided on the bonding surface to communicate the inside and the outside of the lens barrel in a state where the optical filter is bonded.   The lens unit according to claim 1, wherein the lens barrel is provided by resin molding, and a gate mark formed by separating the gate at the time of the resin molding is disposed in at least a part of the recess. .   The lens barrel is provided by resin molding, and apart from the recess, a gate trace recess is provided in which a gate trace formed by separating the gate at the time of the resin molding is provided. The lens unit according to claim 1.   The lens unit according to claim 3, wherein an adhesive is placed in the recess for the gate mark.   The lens unit according to any one of claims 1 to 4, wherein a blocking member that closes the communication groove is provided in the communication groove.   A camera module comprising the lens unit according to any one of claims 1 to 5 and an imaging device that captures an image formed by the lens unit.

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