JP3835620B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging device, and more particularly to a wide-angle imaging device with improved environmental resistance.

  In recent years, imaging devices for various uses such as outdoor use have been put into practical use as performance of downsizing of image sensors such as charge-coupled devices (CCDs) and complementary metal-oxide semiconductors (CMOS) has been put into practical use. Such techniques have been proposed.

  In Patent Documents 1 to 4, a ring-shaped protrusion formed on the periphery of a lens barrel made of a resin material that houses and holds a lens is attached by thermal welding so as to cover the front-side periphery of the first lens. A technique for tightening is disclosed.

  Patent Documents 5 to 8 disclose a technique for projecting the convex surface of the first convex lens from a case or the like as a means for ensuring a wide visual field range for the lens system.

  Further, Non-Patent Document 1, Patent Documents 8 and 9 are technologies used for underwater cameras and the like, in which the first wide-angle lens is directly hermetically sealed without using protective glass. It is disclosed.

  Furthermore, Patent Documents 10 to 12 disclose a technique for hermetically sealing a case opening with a lens barrel.

Japanese Unexamined Patent Publication No. 02-198403 JP 11-313235 A Japanese Utility Model Publication No. 04-101511 Japanese Patent No. 2679784 Japanese Utility Model Publication No. 06-055871 Japanese Patent Laid-Open No. 02-280107 Japanese Patent Laid-Open No. 05-077272 Japanese Utility Model Publication No. 02-064927 Japanese Patent Laid-Open No. 09-265035 JP 2002-090603 A Japanese Patent Laid-Open No. 05-241227 Japanese Patent Laid-Open No. 08-029851 JP 2001-290086 A Japanese Utility Model Publication No. 62-017091 JP 2000-175091 A Japanese Utility Model Publication No. 06-064244 Japanese Utility Model Publication No. 03-006370 JP 05-154102 A JP 2002-090603 A Japanese Utility Model Publication No. 03-005120 JP 2002-098878 A Japanese Patent Laid-Open No. 09-265035 Japanese Unexamined Patent Publication No. 03-072789 Utility Model Registration No. 3084259 Japanese Patent Laid-Open No. 2002-13962 JP 2002-098874 A JP 04-051105 A Japanese Unexamined Patent Publication No. 63-141011 JP 2002-221750 A JP 2000-284422 A JP-A-10-133263 Photo Industry, Vol.50, 1992, No.7, P.11-12, New Product Introduction

  However, the above-described proposed technique may not always be sufficient in environmental resistance performance such as waterproof performance, and further technical improvement has been desired. The present invention has been made in view of the current situation, and an object thereof is to provide an imaging apparatus with improved environmental resistance.

Therefore, in order to solve this problem, the present invention provides:
According to an aspect of the imaging apparatus of the present invention on the apparatus main body side, a wide-angle lens group positioned at least on the incident side among the lens groups arranged on the solid-state imaging device so that the optical axes coincide with each other has an optical axis interval by a lens barrel. In an imaging apparatus having an imaging apparatus body that is housed and disposed in a position-held state and in which the first lens in the wide-angle lens group is formed with a convex surface that forms a light image incident area,
The first lens has a rising portion formed on its outer peripheral surface side so as to extend in parallel with the optical axis toward the convex surface side, and a surface orthogonal to the lens optical axis from the rising portion base side A ring-shaped flat portion with a diameter expanded along the inside,
On the other hand the front side of the lens barrel is fixed to the convex surface of the first sheet of the lens through the barrel locking portion provided at the base side of the lens barrel so as to protrude toward the subject, the 1 A cylindrical pressing member having an opening (hereinafter referred to as an annular opening) defined by an annular pressing portion that presses and supports the outer peripheral edge of the subject lens side of the first lens,
A first ring-shaped step portion having a pressing portion formed by enlarging the inner periphery of the pressing member located on the lower side of the annular pressing portion and facing the ring circular flat portion is provided. By pressing the ring-shaped flat part by the pressing part of the ring-shaped step part, the opening of the pressing member is sealed ,
Further, the lens barrel tip side is positioned and held on the lower surface side of the ring-shaped flat portion of the first lens directly or via a second lens so that the lens barrel is not exposed to the subject side. Features. Here, the optical axis interval refers to the interval between lenses in the optical axis direction.
The pressing member may be a screw-in type, or may be fitted to the outer periphery of the lens barrel to press the first lens in the optical axis direction. The first lens may be positioned in the optical axis direction by contacting a predetermined surface on the subject side of the second lens.
The first and second lenses may be positioned in the optical axis direction by contacting the lens barrel. Further, the coating to be applied to the subject side surface of the first lens may be eliminated.

In the configuration in which the imaging device main body is housed and fixed in the camera case, a second ring-shaped step portion on which a seal ring is placed is provided on the outer peripheral side of the pressing member, and the convex surface of the first lens The seal ring placed on the second ring-shaped stepped portion presses the support surface on the inner side of the camera case so that the tip end side of the holding member including the protrusion protrudes from the opening of the camera case that houses the imaging device main body. The front end of the lens barrel is positioned and held on the lower surface side of the ring-shaped flat portion of the first lens so that the lens barrel is not exposed to the subject side. in a state where the structure, have good that the imaging device body is accommodated and fixed inside the camera case.

Further, the aspect of the imaging device according to the present invention is a surface contact seal structure in which the pressing portion of the first ring-shaped stepped portion is brought into contact with the ring circular flat portion by surface contact to perform liquid-tight sealing, that is, hermetic sealing. It may be a seal structure in which a liquid-tight seal is performed by interposing a seal ring between the pressing portion of the first ring-shaped stepped portion and the ring-circular flat portion. In this case, it is better to use an O-ring.
In particular, when the seal ring is an O-ring, in order to prevent damage to the O-ring without pushing the O-ring more than the specified pressure, a ring-circular shape of the pressing portion of the first ring-shaped stepped portion is used. An O-ring storage groove is provided on the side facing the flat portion, and the specified pressure of the O-ring is set according to the storage height of the storage groove, or the O-ring is pressed at a position facing the lens barrel of the pressing member. An amount regulating surface is provided, and the pressing member is engaged with the regulating surface to set the prescribed pressure of the O-ring, or further, the amount of O-ring pressing on the outer peripheral edge of the convex surface of the first lens It is preferable to provide a regulating surface and set the prescribed pressure of the O-ring by locking the pressing member to the regulating surface.

  Further, when the present invention is used as a waterproof camera for rear monitoring for automobiles, it is necessary to ensure a wide viewing angle without interfering with the light incident on the first lens. When used in this way, the top surface of the annular opening of the pressing member is extended in the light image incident maximum angle (viewing angle) of the first lens or in the retracting direction, or the first lens The top surface of the annular opening of the pressing member facing the lens may extend at a position lower than the outer peripheral edge of the convex surface of the first lens.

In addition, when the wide-angle lens group holds the position of the optical axis by the lens barrel, the optical axis distance is narrow in order to achieve miniaturization regardless of the wide viewing angle. Maintaining accuracy is extremely important.
Therefore, in the present invention, the first lens has two support surfaces formed on the outer peripheral surface thereof so as to extend in parallel with the optical axis toward the convex surface side, and the first support surface. Is a support surface for the pressing member, and the second support surface is a support surface for the lens barrel, and each of the support surfaces is positioned in a plane orthogonal to the optical axis so as to be movable in the optical axis direction by the counterpart member. It is regulated.
A camera case having an opening; a wide-angle lens group housed in a lens barrel; a cylindrical pressing member having an opening defined by an annular pressing portion; and a step provided on an outer periphery of the pressing member; A rising portion having a predetermined diameter provided on the imaging side of the first lens in the wide-angle lens group, and a flat portion substantially orthogonal to the optical axis continuously provided on the rising portion, The pressing member presses the flat portion of the first lens, the opening of the pressing member is sealed by the first lens, and the convex surface of the first lens is the pressing member. The holding member is screwed and fixed to the outer peripheral portion of the lens barrel so as to protrude outward from the opening of the member, and the holding member screwed and fixed has its tip protruded from the opening of the camera case and The camera case is supported by the stepped portion of the holding member. Open circuit, characterized in that it is housed and fixed to said camera case to be sealed in.

  As described above, according to the present invention, it is possible to obtain an imaging apparatus that is suitably applied in environmental resistance such as waterproof performance, and is particularly effective as a rear monitoring (rear viewing camera) mounted on an automobile.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

1 is a cross-sectional view of the imaging apparatus according to the present embodiment, FIG. 2 is a perspective view of the imaging unit, FIG. 3 is a front view of the imaging unit, and FIG. 4 is a perspective view in which the imaging unit is incorporated in the front case.
As shown in FIG. 1, the imaging apparatus 1 of the present embodiment includes a front case 2 and a rear case 3, and a seal 4 is inserted between the front case 2 and the rear case 3 so as to be hermetically sealed. As shown, the imaging unit 10 is incorporated in the case. The front case 2 and the rear case 3 are fixed to a boss (not shown) of the front case 2 by screwing with a screw inserted through a hole (not shown) of the rear case 3 from the rear surface of the rear case 3.

  5 and 6 are exploded perspective views of the imaging unit 10, and FIG. 7 is a cross-sectional view taken along line AA of the front view of the imaging unit 10 shown in FIG. The imaging unit 10 includes an imaging device main body 20, a form ring 40, an adjustment ring 42, a ring fixing plate 44, a lens holder 46, a CCD substrate 48, and a power supply substrate 50 in order from the subject side.

  The imaging apparatus main body 20 (lens assembly) includes a first lens 23, a second lens 24, a diaphragm 29, a third lens 25, a fourth lens 26, a fifth lens 27, and a sixth lens in order from the subject side as a wide-angle lens group. 28. In the present embodiment, a mask is provided between the diaphragm 29 and the third lens 25 to block incident light from the effective light beam of the lens. This is increased or decreased or moved in view of actual lens performance. You may let them.

The first lens 23 is formed with a convex surface 239 on the light image incident side, and the outer peripheral portion has a step-cut structure as shown in the enlarged views of FIGS. 10 and 11, specifically, the convex surface. 239 A first step portion 231 (first support surface) which is a rising portion formed on the outer peripheral surface edge side so as to extend in parallel with the optical axis, and a flat surface for mounting the O-ring 34 which is enlarged in diameter from its base end. A ring-shaped stepped protrusion 230 having a portion 230a is provided. Further, a second step portion 232 (second support surface) having a diameter larger than that of the first step portion 231 is provided below the ring-shaped step protrusion 230. Then, the O-ring 34 is disposed on the ring-shaped flat portion 230 a on the upper surface of the ring-shaped step protrusion 230 that is a step-cut portion provided on the outer peripheral portion of the lens 23.
On the other hand, on the front side of the lens barrel 32, the convex surface 239 of the first lens 23 is projected via the lens barrel screwing portion 302 provided on the base side inner periphery so as to protrude toward the subject side. A pressing member 30 that is screwed and fixed to the lens barrel 32 is provided. The pressing member 30 hangs down the lower side 192a of the annular opening 192 set narrowly toward the outer peripheral edge of the convex surface 239 of the first lens in the direction of the optical axis, and the base side thereof is (rectangular). A first ring-shaped step portion 310 having a pressing surface 301 facing the ring-shaped circular flat portion 230a whose diameter is increased, and the pressing surface 301 of the first ring-shaped step portion 310 and the ring The pressing member 30 seals the first lens 23 by the clamping pressure of the circular flat portion 230a.
The second step portion 232 is locked to a step portion 321 provided on the inner peripheral side of the distal end of the lens barrel 32, and is formed by an annular protrusion 192 of the screw-type pressing member 30 that is screwed with the outer peripheral portion of the lens barrel 32. As shown in FIG. 11, the first lens 23 is pressed substantially in the direction of the optical axis OA via the first step portion 231 and the convex outer edge 234 thereof. At this time, the O-ring 34 is pressed by the lens pressing member 30 and the ring-shaped flat portion 230 a on the upper surface of the ring-shaped step protrusion 230 of the first lens 23. In addition, fitting, caulking, welding, etc. can be illustrated as latching other than screwing.
Further, since the first step portion 231 and the second step portion 232 which are the rising portions are extended in parallel to the optical axis toward the convex surface side on the outer peripheral surface side, the two support surfaces are provided. That is, the first step portion 231 has the same diameter as the lower side 192a of the annular opening 192 of the pressing member 30 to function as a support surface for the pressing member 30, and the second step portion 232 is the tip of the lens barrel 32. The diameter is slightly smaller than the stepped portion 321 provided on the inner peripheral side, and functions as a support surface for the lens barrel.
As a result, the positions of the support surfaces defined by the first step portion 231 and the second step portion 232 are regulated within the plane perpendicular to the optical axis so as to be movable in the optical axis direction by the counterpart member. The lens pressing member 30 and the first lens 23 are hermetically sealed via an O-ring 34, and waterproof performance is obtained. Here, as will be described later, the rising portion 231 is effective for projecting the lens 23 outward and obtaining a wide viewing angle. However, as described above, it can also function as a support surface for the pressing member. .

  In the lens holding member 22 that holds the fourth lens 26, the fifth lens 27, and the sixth lens 28, the three key grooves 21 are linear, and the position at which the outer periphery of the lens holding member 22 is equally divided into three. Provided in relation. In this figure, only one keyway 21 is represented. In this embodiment mode, the number is not limited to three and can be provided as appropriate.

  The foam ring 40 is made of foamed rubber, has an annular shape, and is inserted into the imaging device main body 20. The adjustment ring 42 is threaded on the inside, and is fitted to the imaging device main body 20 so as to be freely rotatable.

  The ring fixing plate 44 is fixed to the imaging device main body 20 by the first and second tap tight screws 80 and 82 so as to sandwich the adjustment ring 42. At this time, the design is taken into consideration so that the adjustment ring 42 does not fall off while the rotation degree of the adjustment ring 42 is maintained.

  The lens holder 46 is linearly provided with three keys 47 that are key-fitted with the three key grooves 21 provided in the lens holding member 22 inside. In this figure, one key 47 is represented. In this embodiment mode, the number is not limited to three and can be provided as appropriate.

  Further, the lens holder 46 is configured so that a male screw is processed to a predetermined length on the outer periphery thereof and is screwed with a screw applied to the inside of the adjustment ring 42. Therefore, when the adjustment ring 42 rotates, the key fitting serves as a guide, and the lens holder 46 moves back and forth in the optical axis direction without rotating.

  Note that when the lens holder 46 is in a predetermined position immediately before being fitted with the imaging apparatus main body 20 and being in the designed focus position, the end of the lens holder 46 close to the subject comes into contact with the foam ring 40. Due to the pretension generated when the foam ring 40 is compressed by being pushed by the lens holder 46, the threaded portion in which the adjustment ring 42 and the lens holder 46 are fitted and the entire structure of the adjustment ring 42 are unidirectional. It is offset and is not affected by the dimensional change of the accommodation portion of the adjustment ring 42 due to backlash of the threaded portion or variations in the component size.

  The ring fixing plate 44 is formed with a female thread portion 45 that is parallel to the outer periphery of the adjustment ring 42. By attaching the ring fixing screw 56 at the pointed end to the female thread portion 45 and integrating the adjustment ring 42 and the ring fixing plate 44, the focus is securely fixed. Further, since the lens barrel 32 is not directly fixed when the focus is fixed, a load is not directly applied to the lens. Therefore, the lens is not distorted, and the deterioration of the imaging quality can be avoided.

  A CCD substrate 48 provided with a CCD as an imaging device is fixed to the lens holder 46 by third and fourth tap tight screws 84 and 86. As described above, the lens holder 46 is key-fitted to the imaging apparatus main body 20, and its position is adjusted by the adjustment ring 42, and the accuracy of each component is appropriately managed, so-called. Positioning called “vertical alignment” or “tilt adjustment” is not required. By attaching the CCD substrate 48 so as to be perpendicular to the lens holder 46, the imaging surface becomes perpendicular to the optical axis direction. Therefore, the adjustment of the imaging surface may be performed only in the X and Y axis directions and the rotation direction (θ) when the optical axis direction is the Z axis direction. The tap tight screw may be a tapping screw or a normal screw depending on circumstances.

  A power supply substrate 50 having a function of supplying power to the CCD substrate 48 and outputting a signal output from the CCD substrate 48 to the outside of the imaging unit 10 is attached to the CCD substrate 48. The imaging unit 10 is screwed to the front case 2 through first and second exterior set screw holes 92 and 94 provided in the imaging apparatus main body 20.

  With the above configuration, focus adjustment is possible without adjusting the lens itself, and the efficiency of adjustment work is improved. In addition, by using the adjustment ring 42, it is possible to independently perform focus adjustment and so-called “optical axis adjustment” in which the lens optical axis coincides with a predetermined pixel of the image sensor. Further, since the focus can be fixed by fixing the adjustment ring 42, it is possible to avoid the lens from being distorted without applying a load directly to the lens.

  The imaging apparatus main body (lens assembly) 20 will be described in detail. FIG. 8 is a cross-sectional view of the imaging apparatus main body 20, and FIG. 9 is a cross-sectional view in which the opening of the front case 2 is sealed with the pressing member 30 and the first lens 23. A lens barrel 32 is disposed on the subject side of the imaging apparatus main body 20, a first lens 23 is disposed on the subject side of the lens barrel 32, and an outer peripheral portion of the first lens 23 has a step-cut structure. Specifically, on the outer peripheral surface edge side of the convex surface of the first lens, there is a rising portion formed by extending the optical axis in parallel, and a flat portion for O-ring placement that is enlarged in diameter from its base end. An O-ring 34 as a sealing material is disposed on the O-ring mounting flat portion, and the first lens 23 is pressed in the direction of the optical axis OA by the pressing member 30 via the O-ring 34. . Here, the O-ring 34 is formed of hydrogenated nitrile butadiene rubber (HNBR). Nitrile-Butadiene Rubber (NBR) is generally used as a sealing material for waterproof cameras due to its oil resistance and weather resistance. Further, HNBR that improves the ozone resistance, heat resistance, and weather resistance of NBR and extends the deterioration life is more suitable as a sealing material. The position of the first lens 23 in the direction of the optical axis OA is defined by a contact between a predetermined surface on the image plane side of the first lens 23 and a predetermined surface on the subject side of the second lens 24.

  As shown in FIG. 9, a step 55 which is a second ring-shaped step portion is formed on the peripheral portion of the pressing member 30, and an O-ring 54 different from the above-described one is disposed on the step 55. When the pressing member 30 is inserted into the opening of the front case 2, a protrusion 91 (shown in FIG. 2) provided on the imaging device body 20 is positioned in a not-shown recess provided on the back surface of the front case 2, and The opening of the front case 2 is sealed by the pressing member 30 by screwing to a boss (not shown) provided on the back surface of the front case 2 with a screw inserted into the hole 90 provided.

  10 and 11 are enlarged views of the region 70 shown in the cross-sectional view of the imaging device main body 20 in FIG. 8, and a structure in which the opening of the imaging device main body 20 is sealed by the first lens 23 will be described.

  The first lens 23 is held and housed on the subject side of the lens barrel 32, and a small claw-like and annular protrusion 192 is provided at the end of the pressing member 30 toward the inside. By screwing the pressing member 30 into the lens barrel 32, the O-ring 34 disposed between the first lens 23 and the pressing member 30 is pressed and deformed, and the first lens 23 is positioned at the first step portion 231 thereof. In this state, the opening of the pressing member 30 is hermetically sealed by the first lens 23. At this time, the following design considerations are taken.

  First, the inner diameter of the O-ring 34 is designed to be larger than the outer diameter of the first step portion 231 of the first lens 23, and the outer diameter of the O-ring 34 is designed to be smaller than the inner diameter of the pressing member 30. In this way, as shown in FIG. 10, the O-ring before screwing the pressing member 30 into the lens barrel 32 is arranged without being pressed and deformed, and even after the pressing member 30 shown in FIG. 11 is screwed into the lens barrel 32. The O-ring 34 can avoid contact with the inner wall surface of the pressing member 30 and the edge portion 234 (outer edge of the convex surface) of the first lens 23 so as to generate a large frictional force. As a result, unnecessary frictional force and twisting force in the rotational direction are not generated on the O-ring 34, and the O-ring 34 is not easily damaged.

  Furthermore, it has been established as a common sense of design that an antireflection coating is applied to the first lens on the object side in order to prevent irregular reflection inside the lens and ghost, flare and the like due to backlight in the optical design. However, in the case of an imaging device for outdoor use, where the surface of the first lens is exposed and dust or the like can hit the lens surface due to wind or the like, a part of the coating on the surface of the first lens is peeled off, and photographing is performed. Could cause degradation of image quality. Also, cracks in the coating due to thermal expansion cause similar problems. Therefore, in the present embodiment, in the case of an imaging device used in a bad environment, the lens outside the first lens is abolished and the ghost, flare, and the like are not easily generated in this case, contrary to conventional design common sense. It is configured.

  Of course, as long as the imaging device is not used in a bad environment, the coating may be applied as usual. On the other hand, the coating of the first lens may be abolished when there is a possibility that some object may hit the first lens even when it is for indoor use, or when it is susceptible to a change in environmental temperature.

  The imaging apparatus according to the present embodiment that employs a structure in which the opening of the front case 2 is sealed by the pressing member 30 is disclosed in, for example, FIG. Compared to the structure of the following, there are the following operational effects.

  The above is one embodiment of the present invention. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to each of those components and combinations thereof, and such modifications are also within the scope of the present invention. Hereinafter, modifications will be described.

(1) Temperature characteristics In an outdoor camera, the exposed portion is directly exposed to the outside air or receives direct sunlight, so that the temperature fluctuation is large. If the lens barrel is exposed outside the case, the lens barrel will be distorted, twisted and deformed due to temperature fluctuations, and the lens mounting position accuracy will be reduced. The lens barrel is inherently sophisticated enough to affect the optical performance with a deviation of 1/100 mm or less.
On the other hand, if the lens barrel is not exposed from the case as in the present embodiment, the lens mounting position accuracy is not affected even if the pressing member 30 is slightly deformed. The lens mounting position accuracy is compensated by the lens barrel. The lens pressing member 30 can be further prevented from being deformed by heat by forming it with a metal material such as anodized aluminum material or stainless steel material.

(2) Intensity Outdoor cameras, particularly in-vehicle cameras, may exert a force on the camera part during car washing or maintenance. If the lens barrel is exposed to the outside, a force is directly applied to the lens barrel and the lens barrel is deformed, which may affect the lens mounting position accuracy. On the other hand, if the lens barrel is not exposed from the case as in the present embodiment, the force is applied to the pressing member 30 rather, the force applied to the lens barrel is suppressed, and deformation of the lens barrel is suppressed. Therefore, the lens mounting position accuracy is hardly affected. In addition, if the lens pressing member 30 is made of the above-described metal material, deformation due to an external impact can be further prevented.

(3) Resistance to chemicals Outdoor cameras, especially mounted cameras, are easily exposed to oils and oils such as wax, and can be corroded by corrosive chemicals such as polymers. In the configuration where the lens barrel is exposed, there is a concern that the lens mounting position accuracy may be reduced due to the corrosion of the lens barrel, but in this embodiment, the lens barrel is not exposed from the case, so that the lens barrel is not corroded and the lens mounting position Accuracy can be maintained. In addition, if the lens holding member 30 is comprised with the above-mentioned metal material, corrosion can be prevented more.

(4) Tamper resistance Outdoor cameras, especially in-vehicle cameras, etc., must be assumed to be mischievous from the outside. If the lens barrel is exposed, a force is directly applied to the lens barrel, causing lens displacement. Moreover, there is a possibility that the first lens may come off by cutting or peeling off the heat-welded portion with a cutter or the like. On the other hand, in this embodiment, since the lens barrel is not exposed from the case, the first lens is not detached unless the case is opened, and the durability is excellent. In addition, if the lens pressing member 30 is comprised with the above-mentioned metal material, tamper-resistant performance will improve further.

(5) Aging characteristics Each member of the apparatus deteriorates due to a change with time. In particular, the deterioration of the portion exposed to the outside is faster than that of the internal member. In the configuration in which the lens barrel is exposed and the lens is pressed against the lens barrel by heat welding, there is a concern that the pressing portion creeps and the lens is detached. On the other hand, in the present embodiment, the lens barrel is not exposed from the case, and the first lens is not easily detached, and is resistant to changes with time. Note that if the lens pressing member 30 is made of the above-described metal material, it is more resistant to changes with time.

(6) Maintainability In the configuration in which the lens is caulked to the lens barrel by heat welding, it is necessary to replace the lens and the lens barrel at the time of maintenance, which is costly. In this embodiment, the lens is integrated with the lens barrel. Since the first lens is not fixed to the lens, the lens, the lens barrel, and the pressing member can be replaced separately, which is advantageous in terms of cost.

(7) Manufacturability In the configuration in which the lens is pressed onto the lens barrel by thermal welding, the dimensional variations of all the parts to be fixed by thermal welding are overlapped. Although it is difficult to keep constant, in the configuration of the present embodiment, since the lens is not fixed to the lens barrel by heat, the mounting position of the lens does not depend on the dimensional variation of the parts, and the process management It is advantageous in terms of yield. If the lens pressing member 30 is made of the aforementioned metal material, the lens mounting position accuracy is further improved.

(8) Waterproof performance Generally, when performing hermetic sealing with an O-ring, that is, sealing, the compression rate when the O-ring is pressed and deformed is set to 8% as a lower limit and 40% as an upper limit. It is preferable to change the control value of the compression ratio depending on the wire diameter of the ring. That is, when the wire diameter is small, the compression ratio is increased in order to increase the contact area, and conversely, when the wire diameter is large, it is not necessary to take an excessive contact area, so the compression ratio may be small. The compression rate is generally set in consideration of tolerance and aging deterioration.

  On the other hand, according to publicly disclosed materials by manufacturers, etc., waterproofing with O-rings has a compression rate of 15% to 40% at a wire diameter of 2 mm or less, a compression rate of 10% to 30% at a wire diameter of less than 2 to 4 mm, and a wire diameter of 4 mm. In the above, a compression rate of 8% to 20% is considered good. In the present embodiment, in consideration of compression set, a margin of 5% is provided on the high compression side, and the management value of the compression rate is 15% to 35%.

  As described above, the compression ratio must be strictly controlled when sealing with an O-ring. However, in the configuration in which the lens is pressed against the lens barrel by heat welding, as described above, the caulking portion is caused by the dimensional variation of the lens components. Therefore, it is difficult to secure a certain amount of caulking with the heat welding jig. As a result, the compression ratio of the O-ring varies, and it is difficult to achieve a desired waterproof performance. On the other hand, according to the configuration of the present embodiment, the compression rate of the O-ring can be managed very easily by managing the screwing amount and screwing force of the pressing member, so that the yield and the desired waterproof performance can be provided. .

  If the lens pressing member 30 is made of the above-described metal material, the compression rate of the O-ring can be managed more strictly. In addition, since the dimensional accuracy is improved as compared with a general resin molded product, the management of the compression rate is further facilitated.

(9) Downsizing In the configuration in which the lens is pressed against the lens barrel by heat welding, it is difficult to manage the compression rate of the O-ring as described above, so that only a diameter of the O-ring or more can be adopted, and downsizing is achieved. Is difficult. On the other hand, with the configuration of the present embodiment, an extremely small diameter O-ring can be adopted, and the apparatus can be designed to be smaller. Also in this case, if the lens pressing member 30 is made of the aforementioned metal material, the compression rate of the O-ring can be managed more strictly, which contributes to further miniaturization.

(10) Vibration resistance In the configuration in which the lens is pressed against the lens barrel by heat welding, there is a concern that this press may be released due to vibration of the vehicle or the like, particularly in the case of an in-vehicle camera or the like. On the other hand, such a problem does not occur in the configuration of the present embodiment.

(11) Others In the configuration of the present embodiment, in addition to the above, by changing only the pressing member, it is possible to cope with cases having different opening dimensions, so that the degree of freedom in design is high. In addition, by forming the pressing member exposed to the outside with the above-described metal or the like, engraving silk printing or the like can be performed on the pressing member, and the appearance can be easily improved by performing a decoration process or the like. .

  The imaging apparatus according to the present embodiment further has the following operational effects compared to, for example, a structure in which the opening of the front case disclosed in Patent Document 10 and Patent Document 5 described above is sealed by the first lens. Play.

  In the above-described prior art, the mounting position accuracy is ensured by the front case in which the first lens is generally formed of resin. On the other hand, the lens after the second lens is also held and housed in a lens barrel generally formed of resin. However, since the lens barrel itself is attached to the front case, the positional accuracy after the second lens. In addition to the accuracy of the lens barrel itself, the accuracy of the mounting position between the lens barrel and the front case deteriorates. Therefore, the accuracy between the first lens and the second lens deteriorates, and there is room for improvement in the performance of the optical system. On the other hand, in the present embodiment, since the distance between the first lens and the second lens can be determined by the surface accuracy of each lens, an imaging apparatus with very high optical system accuracy is realized.

  The above is the embodiment of the present invention. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to each of those components and combinations thereof, and such modifications are also within the scope of the present invention.

  For example, FIG. 12A shows a structure of a camera body (lens assembly) for a waterproof camera in which the O-ring 34 is not disposed, and the first lens 23A and the pressing member 30A are sealed by direct surface contact. Thus, the pressing surface 301 of the first ring-shaped step portion 310 of the pressing member 30A has a surface contact seal structure in which the ring circular flat portion 230 is brought into contact with the surface by surface contact to perform a liquid-tight seal.

  That is, the first lens 23 </ b> A is a first step portion 231 that is a rising portion formed by forming a light image incident side with a convex surface 239 and extending on the outer peripheral edge side of the convex surface 239 in parallel with the optical axis. (First support surface) and a ring-shaped stepped protrusion 230 having a diameter larger than the base end thereof and having a flat portion 230a for mounting the O-ring 34, and the first stepped portion 231 below the ring-shaped stepped protrusion 230. A second step portion 232 (second support surface) having a diameter is provided, and the pressing member 30 is in surface contact with the ring-shaped flat portion 230a on the upper surface of the ring-shaped step protrusion 230 to be sealed.

FIG. 12B shows a structure of a waterproof camera in which an O-ring 34 is arranged. The O-ring is accommodated on the pressing surface 301 of the first ring-shaped step portion 310 of the pressing member 30B on the side facing the ring circular flat portion 230. A groove 3010 is provided, and the specified pressure of the O-ring 34 is set according to the storage height of the storage groove 3010. According to this configuration, the prescribed pressure of the O-ring 34 is set on the surface of the pressing surface 301 of the first ring-shaped step portion 310 of the pressing member 30B that contacts the ring-circular flat portion 230a, and the O-ring 34 Prevents crushing.
12A and 12B, since the height of the top surface of the pressing member 30A can be set at a position lower than the outer edge of the convex surface 239, the first lens spherical surface ( The light incident on the convex surface 239) can be prevented from being interrupted, and the angle of view can be widened.
In particular, in the structure of the waterproof camera of FIG. 12B, the pressing surface 301 of the first ring-shaped step portion 310 of the pressing member 30A is in surface contact with the flat portion 230a of the first lens so as to wrap the O-ring 34. Therefore, the O-ring 34 is not pushed more than the prescribed pressure, and the O-ring 34 can be prevented from being damaged.

The configuration of the waterproof camera imaging device main body of FIG. 12C is provided with a restricting portion that restricts the movement of the pressing member in the optical axis direction by supporting the proximal end of the pressing member 30C on the step 322 on the lens barrel tip side. It is what.
In other words, the base side of the pressing member 30C is configured as a pressing amount regulating surface of the O-ring 34 by being screwed so as to contact the step portion 322 of the lens barrel 32C at a position facing the lens barrel of the pressing member. The opening edge of the annular opening 192 on the front side of the pressing member 30C is set so as to extend at an angle greater than or equal to the maximum light image incident angle of the first lens.

  In the configuration of FIG. 12D, the lens barrel tip side is formed so that the proximal end side of the pressing member is housed in the ring-shaped groove 323, and the ring-shaped protruding portion 3011 is expanded on the outer peripheral side surface of the pressing member. In this configuration, the movement of the pressing member 30 </ b> D in the optical axis direction is restricted.

  Accordingly, in the configuration of FIGS. 12C and 12D, an O-ring pressing amount regulating surface is provided at a position facing the lens barrel of the pressing member, and the pressing member is locked to the regulating surface so that the O-ring is locked. Since the specified pressure is set, the O-ring is not pushed more than the specified pressure, and the O-ring can be prevented from being damaged.

FIG. 13 shows another embodiment of the camera body for a waterproof camera. The first lens 23E is formed by extending the outer peripheral surface of the first lens 23E in parallel with the optical axis toward the convex surface. The first support surface 231 is a support surface for the pressing member 30, the second support surface 232 is a support surface for the lens barrel 32, and the respective support surfaces 231, 23 are provided. 10 is similar to FIG. 10 and FIG. 12 in that the position is regulated within the plane orthogonal to the optical axis so as to be movable in the optical axis direction by the counterpart member.
That is, the first lens 23E is a first step portion 231 which is a rising portion formed by forming the light image incident side with the convex surface 239 and extending the outer peripheral surface of the convex surface 239 in parallel with the optical axis. (First support surface) and a ring-shaped stepped protrusion 230 having a flat diameter 230a for mounting the O-ring 34, and a first stepped portion 231 below the ring-shaped stepped protrusion 230. A second step portion 232 (second support surface) having a small diameter is provided, and the pressing member 30 is sealed via an O-ring 34 to a ring-shaped flat portion 230 a on the upper surface of the ring-shaped step protrusion 230.

In this embodiment, the annular opening 192 on the front side of the pressing member 30E may be brought into contact with the outer peripheral edge of the convex surface 239 of the first lens (FIGS. 13A and 13D). The annular opening 192 may be brought into contact with or not in contact with one step portion 231 (first support surface).
That is, in FIG. 13A, the peripheral side of the annular opening 192 of the pressing member 30E extends downward in a direction to retract from the maximum optical image incident angle of the first lens 23E. The incident light is configured not to be blocked by the opening edge to ensure a wide viewing angle, and the second step portion 232 of the first lens 34E is fitted to the inner periphery of the lens barrel 32E so that the optical axis Prevents deviation.
In FIG. 13B, the first step 231 of the first lens 23E is slidably supported by the annular opening 192 of the pressing member 30E (first support surface), and the second step 232 is This is a configuration (second support surface) supported by the inner peripheral surface of the lens barrel 32E.
According to this embodiment, since the first lens 34E is supported by the pressing member 30E and the lens barrel 32E, there is a difference in the coefficient of thermal expansion between the first lens 34E, the pressing member 30E, and the lens barrel 32E. Even if there is, since the first lens 34 is supported by either one or both of the pressing member 30E and the lens barrel 32E, the optical axis can be reliably prevented from shifting.
The configuration of the waterproof camera image pickup apparatus main body in FIG. 13C is a modification of FIG. 13B, and the first lens 24E has a ring shape of the inner wall surface of the pressing member 30E and the first lens. It is different from the configuration of FIG. 13B in that it is supported on the outer peripheral surface of the step projection 230 (first support surface).
According to this embodiment, since the first lens 24E is supported by the inner peripheral surface 301 of the pressing member 30E, the first lens 23E is formed at the opening edge of the annular opening 192 of the pressing member in FIG. In particular, it can be firmly supported against the radial force.
The configuration of FIG. 13D is a configuration in which the shape of the opening edge of the annular opening 192 provided at the subject-side tip of the pressing member 30E is matched to the incident angle of the light incident on the first lens.
Accordingly, when the outer edge of the convex surface 239 of the first lens 23E is pressed by the annular opening 192 of the pressing member 30E, the shape of the annular opening edge can be configured in accordance with the incident angle of the light incident on the lens. The viewing angle can be secured, and the strength of the ring-shaped protrusion 192 of the pressing member can be increased by increasing the thickness within a range in which the incident angle of light incident on the lens is not narrowed. Can be prevented from being damaged by strong impact.

  That is, as shown in the comparative example of FIG. 14, in the pressing of the convex surface 239F of the first lens 23F by the pressing ring 192F of the opening edge of the annular opening 192, the maximum necessary condition of the rear monitoring camera is limited by the light beam. This creates a restriction on the angle of view (the maximum incident angle of light image). However, in the embodiment of FIG. 13, instead of pressing the convex surface 192 of the first lens 23E, the outer peripheral edge deviated from the angle of view of the first lens 23E or the circumference of the first step portion 231. By pressing the surface or the peripheral surface of the ring-shaped protrusion 230, the restriction of the viewing angle can be eliminated. Therefore, according to the present embodiment, a desired degree of viewing angle can be secured, and the size of the outer diameter of the tip portion, which has many restrictions on arrangement, can be reduced.

  Further, in the method of pressing the convex surface of the first lens 23F with the annular opening edge of the pressing member 30F as in the comparative example of FIG. 14, excessive stress is generated at the annular opening edge, and the strength of the annular opening edge is increased. Is required. In order to prevent deformation of the annular opening edge due to this stress, the strength of the annular opening edge must be increased. In order to increase the strength, the thickness of the presser ring must be increased. As a result, the angle of view incident on the first lens is inevitably limited, and the wide-angle field of view, which is a feature of the rear monitoring camera, must be sacrificed.

As shown in FIG. 15, in the design of the first lens 23, the pressing force applied to the connection point of the ring-shaped protrusion 230 connected to the base of the first step portion 231 of the first lens 23 is defined. the standard 350 N / ^{m 2} must be designed so as not to exceed (Newton-per-square meter), in particular, the thickness T of the ring-shaped protrusion 230 which is provided on the side surface of the first sheet of the lens 23, 0.7 mm or more Must consist of
Therefore, the first step portion 231 is also preferably configured to be 0.7 mm or more, and specifically, is calculated from the length of the diameter of the O-ring 34 and the length of the pressing portion of the pressing member in the optical axis direction. The
For example, since the O-ring 34 is compressed by the pressing member 30 at a value of 15 to 40%, if the diameter of the O-ring is 0.6 mm from the viewpoint of waterproofness, the optical axis direction when the O-ring is crushed The length (crushing diameter X) is 0.435 mm. (Compression rate is calculated at 15%)
When the pressing member 30 is formed of molded plastic, the thickness Y and the width Z on the O-ring pressing surface side of the pressing member necessary to achieve the compression ratio are Z * X> (0.6 / 2) ² >Z> 0.65 is derived from π, and Y> 0.7691 is derived from Y = √0.91 * Z.
Therefore, the length S in the optical axis direction of the upright portion is
It is understood that S> 0.435 + 0.7691 = 1.2041 mm is the minimum length.

(Detailed description of the first embodiment (sealing structure))
Now, with respect to the first embodiment, a point that enables wide-angle imaging while having a sealing structure will be described in detail.
FIG. 16 shows that the O-ring shown in FIGS. 1 to 11 in the first embodiment is hermetically sealed instead of the hermetically sealed without using the O-ring. 1 shows an imaging apparatus having a structure.
According to FIG. 16, the first lens 700 has a convex surface 702 for wide-angle shooting on the subject side, and an imaging lens surface 707 on the imaging side (an imaging element side not shown). The first lens includes a first diameter portion 701 having a diameter r, a second diameter portion 704 having a diameter r ′ satisfying r ′> r, and a diameter r ″ third satisfying r <r ″ <r. And a diameter portion 709. By these diameter portions, a rising portion 721 having a predetermined diameter (diameter r) on the subject side of the first lens 700 and having a predetermined rising length l is formed. In addition, a flat portion having a length l ′ that is substantially orthogonal to the optical axis is formed continuously from the rising portion 721 by these diameter portions.
Further, the first lens 700 is a step in which a first lens positioning projection 711 formed on the lens barrel 706 is formed by a second diameter portion 704 and a third diameter portion 709 on the imaging side of the first lens 700. By positioning the part, it is positioned and accommodated in the lens barrel 706.

Further, the first lens 700 is pressed and fixed to the lens barrel 706 by pressing the flat portion 703 of the first lens 700 toward the imaging side by a ring-shaped pressing portion 705 disposed on the subject side. The pressing member 705 is screwed and fixed to the outer peripheral portion of the lens barrel 706, and although not shown, a step portion is provided on the outer periphery of the pressing member 705. Similarly, the pressing member 705 is opened from an opening of a camera case (not shown). And the opening of the camera case is sealed so that the stepped portion of the pressing member 705 is inserted into the opening of the camera case.
In addition, the inner periphery on the subject side of the pressing member 705 is configured to extend along the outer periphery of the first lens 700, and in particular, the outer periphery of the rising portion 721 of the rising portion 700 of the first lens 700. An inner peripheral surface 724 of the pressing member 705 is formed over substantially the entire area.

Here, in the case of an imaging device that requires particularly high sealing performance, it is required to maintain a high pressing force for pressing and fixing the first lens 700 to the lens barrel 706. For this reason, the pressing member 705 that presses the first lens 700 against the lens barrel 706 needs to secure a large thickness m in order to keep the flat portion 703 of the first lens 700 with a high pressing force. If the wall thickness m is small, the ability to press and hold the first lens 700 is low and sufficient sealing performance cannot be obtained, or even if sufficient sealing performance is initially obtained, it is strongly affected by changes over time. After that, sufficient sealing performance cannot be obtained.
Therefore, although depending on the required sealing performance and the material of the pressing member, the thickness m of the pressing member 705 for pressing and holding the first lens 700 must have a certain size or more.

Here, instead of the first lens 700, when using a holding member 705 having a wall thickness m in which sealing performance is ensured as well as lifting using the first lens 722 that does not have the rising portion 721, wide-angle performance. FIG. 16 shows an example in which the image quality is significantly impaired.
The convex surface on the subject side of the first lens 722 is shown as a dotted line 722 in FIG. The maximum wide-angle field of view of this image pickup apparatus is as shown by line 723. In other words, a light beam having a wider angle than the line 723 is blocked by the side surface 724 of the pressing member 705, and as a result, the wide-angle field of view is narrowed. Here, since the thicker pressing member 705 must be used as the sealing performance is required, it is difficult to achieve both the sealing performance and the viewing angle.
On the other hand, the maximum wide-angle field of view of the imaging device in the case of the first lens 700 provided with the rising portion 724 is a line 708, and compared with the case of the first lens 722 having no rising portion, the side surface 724 of the pressing member 705. Therefore, a remarkable wide-angle field of view can be obtained.
In other words, by setting the rising portion 724 to be equivalent to or more than the thickness m of the holding member 705 sufficient to satisfy the sealing performance, a high wide-angle visual field can be realized while ensuring a sufficient sealing performance. .

Here, the first lens 700 has a circular cross section perpendicular to the optical axis as an embodiment, but the present invention can form an optical system that can form an image of an object on an image sensor (not shown). Needless to say, an oval shape or a square shape may be used.
Further, the first lens 700 has the third diameter portion 709 larger in diameter than the first diameter portion 701 and smaller in diameter than the second diameter portion 704 as an embodiment. Needless to say, the diameter is not limited to 709, and the first lens 700 may not have the third diameter portion 709 as long as the first lens 700 is positioned and held by the lens barrel 706. The first lens 700 does not need to be directly positioned on the lens barrel 706. For example, a second lens (not shown) is positioned and accommodated in the lens barrel 706, and the first lens 700 is positioned by the second lens (not shown). Alternatively, it may be indirectly positioned as stored in the lens barrel 706.

(Detailed description of the first embodiment (sealing and sealing structure))
With respect to the first embodiment, a detailed description will be given of the fact that wide-angle imaging is possible while having a hermetic sealing structure using an O-ring as a sealing material.
FIG. 17 shows that a high wide-angle field of view can be realized while ensuring sufficient hermetic sealing performance for the embodiment hermetically sealed using the O-ring shown in FIGS. 1 to 11 among the first embodiments. FIG.
In FIG. 17, the same reference numerals as those in FIG. 16 indicate the same contents, and thus the description thereof is omitted.
FIG. 17 uses the first lens 700 having the rising portion 721 as in FIG. 16, except that the O-ring 712 is disposed between the flat portion 703 of the first lens 700 and the pressing member 705. The difference from FIG. 16 is that the holding member 705 that holds and holds the flat portion 703 of the first lens 700 on the imaging side has a protrusion 701 at the tip of the first lens 700 on the convex surface 702 side.

Here, the pressing member 705 is configured to have a corresponding thickness m so as to obtain a corresponding required hermetic sealing performance by pressing and holding the flat portion 703 of the first lens 700 via the O-ring 712. ing.
In the case of an imaging device that requires particularly high hermetic sealing performance, the first lens 700 is pressed and fixed to the lens barrel 706 via the O-ring 712, and the O-ring 712 is compressed at a suitable compression ratio for hermetic sealing. It is necessary to Therefore, the pressing member 705 that presses the first lens 700 against the lens barrel 706 via the O-ring 712 keeps the flat portion 703 of the first lens 700 with a high pressing force, and the O-ring 712 is correspondingly It is necessary to ensure a large wall thickness m in order to compress and hold at the compression ratio. If the wall thickness m is thin, the ability to press and hold the first lens 700 is low and the O-ring 712 cannot be compressed with a corresponding compression ratio, and the required hermetic sealing performance is obtained. I can't. In addition, even if sufficient sealing performance is obtained at the beginning, the pressing member 705 may be deteriorated due to changes over time, and the press-holding ability may be deteriorated so that sufficient sealing performance cannot be obtained.
Therefore, although depending on the required sealing performance and the material of the pressing member, the thickness m of the pressing member 705 that presses and holds the first lens 700 via the O-ring 712 must have a certain size or more. .

Next, a description will be given of the protrusion 701 disposed at the tip of the first lens 700 on the convex surface 702 side of the pressing member 705 that presses and holds the flat portion 703 of the first lens 700 on the imaging side.
The protrusion 701 is the same member as the annular protrusion 192 shown in FIGS. The protrusion 701 (protrusion 192) surely abuts on the convex surface 702 of the first lens 700 and presses it toward the imaging side, but it is the protrusion 701 (protrusion 192) that actually presses. In FIG. 17, the imaging side surface portion 726 of the pressing member 705 that press-deforms the O-ring 712 is not the portion but the elliptical upper portion (subject side) of the O-ring 712 in FIG. For this reason, the main use of the protrusion 701 (protrusion 192) is not the pressing but the compression ratio setting of the O-ring 712 as described below.
As described above, the O-ring 712 needs to manage the compression ratio management value from 15% to 35% in this embodiment. For this reason, conventionally, when the pressing member 705 is screwed and fixed, the screwing amount (screwing rotation speed) of the pressing member 705 and the movement amount due to screwing of the pressing member 705 are detected in the manufacturing process of the imaging apparatus, and specified. 17 was made constant by screwing up to the detected amount, and as a result, the compression ratio of the O-ring 712 was managed.
Here, it is not easy to detect the amount of screwing and the amount of movement, and the number of extra manufacturing facilities and processes increases in the manufacturing process, which has a great adverse effect on productivity, yield, and cost.

However, according to the present embodiment, by setting the above-described dimension n at a position where the above-described protrusion 710 (protrusion 192) contacts the convex surface 702 of the first lens 700, that is, the protrusion 710 (protrusion 192). ) Is in contact with the convex surface 702 so that the pressing member 705 cannot be screwed in, and the size n of the compression space of the O-ring 712 is designed so that the O-ring 712 is compressed at an appropriate compression ratio. Therefore, it is possible to appropriately manage the compression ratio of the O-ring 712.
Therefore, by simply managing only the screwing torque of the pressing member 705, it is not necessary to detect the amount of screwing or the amount of movement, and the manufacturing process can be reduced, the yield can be improved, and the manufacturing equipment can be reduced as compared with the past. it can.

  Since the protrusion 710 (protrusion 192) is not required to press and hold the first lens 700, the thickness m as described above is not necessary, and can be configured with a relatively thin thickness. . Therefore, although the wide-angle field of view of the first lens 700 is slightly impaired as a result, as shown by the line 725 indicating the wide-angle field of view shown in FIG. It is clear that this is secured.

Next, the dimensions of the assembling members designed for the vehicle-mounted imaging device according to this embodiment will be described.
FIG. 18 is generally called a differential pressure test, and applies a pressure by a predetermined medium to the front surface portion of the imaging apparatus of the present embodiment through a first path, and a reference through a second path. The result of having tested the pressure difference in both the paths at the time of applying to this member by changing the diameter of the O-ring 712 is shown. In this test, the smaller the differential pressure value on the vertical axis, the better the sealing performance. The same diameter is measured five times.
In general, an in-vehicle imaging device is required to perform five tests in the above differential pressure test and to be 10 Pa or less. Accordingly, the diameter of the O-ring 712 is O.D. It is necessary to design with 5 mm or more. On the other hand, when the diameter of the O-ring 712 is set to 3.0 mm or more, the pressing force by the pressing member 705 necessary to change the compression ratio of the O-ring from 15% to 35% is the second diameter portion 704 of the first lens 700. Although it is also influenced by the thickness of the glass, it exceeds 350 * 10 ⁸ N / m ² of the glass strength of a general optical glass lens, and becomes NG in terms of strength. Therefore, the diameter of the O-ring 712 is preferably 0.5 mm or more and 3.0 mm or less.

  Further, as apparent from FIG. 18, when the diameter of the O-ring 712 is 1.4 mm or more, the measured differential pressure is almost settled in the vicinity of zero. For this reason, it is not preferable to select a more expensive O-ring having a diameter of 1.4 mm or more. In addition, since a large value is required for the pressing force as the diameter increases, it is necessary to make various members strong, so there is a concern that the cost of various members may be increased and the size of the entire apparatus may be increased.

Further, if the length l of the flat portion 703 of the first lens 700 is equal to or less than a predetermined length, there is a problem that the first lens 700 is likely to be damaged by an impact or the like during manufacture or transportation. Therefore, the design is required to be 0.7 mm or more. On the other hand, when the O-ring 712 is pressed and deformed, the O-ring 712 is deformed so as to be in close contact with the first diameter portion 701 of the first lens 700 and the inner peripheral surface of the pressing member 705 as shown in FIG. Even if it does not come in contact, the sealing performance is significantly improved.
Therefore, the O-ring 712 is required to be more preferably 0.7 mm or more and 1.4 mm or less.

Here, an example will be described in which a 0.6 mm O-ring 712 is designed to make the imaging device smaller. When the compression ratio is managed at 15%, the thickness n in the optical axis direction of the O-ring 712 is 0.435 mm.
Further, the thickness Z (corresponding to l ′ of the flat portion 703) in the direction orthogonal to the optical axis of the O-ring 712 is
From Z * n> (0.6 / 2) 2π, Z> 0.65 mm.
Here, the wall thickness m of the pressing member is:
m = √0.91 * l ′.
Therefore, the minimum length l required for the rising portion 701 of the first lens 700 is
From 1 = n + m, l = 0.435 + 0.7691 = 1.2041 mm.
Therefore, it is more preferable that the rising length of the rising portion 701 is at least 1.2042 mm.

  Here, the inner diameter of the O-ring 712 is larger than the outer diameter of the first diameter portion 701 of the first lens 700, and the outer diameter of the O-ring 712 is designed to be smaller than the inner diameter of the pressing member 705. Even after being screwed into 706, the O-ring 712 generates a large frictional force between the inner wall surface of the pressing member 705 and the edge portion formed by the first diameter portion 701 and the flat portion 703 of the first lens 700. Needless to say, such contact is avoided. As a result, unnecessary frictional force and twisting force in the rotational direction are not generated in the O-ring 712, and no damage is caused.

In the above embodiment, the protrusion 710 (protrusion 192) is provided at the tip of the pressing member 705 in order to manage the compression ratio of the O-ring 712, but the present invention is not limited to this. No protrusion may be provided at the tip like the pressing member shown in FIG. 16, and the screwing amount of the pressing member 705 is set near the threaded screw portion of the lens barrel 706 to which the pressing member 705 is screwed and fixed. It is good also as what provided the member to regulate.
Moreover, although the example which used O-ring as a sealing material was shown, this example is not limited to this, It cannot be overemphasized that the sealing material of a liquid form or a tape form may be sufficient.

  The following summarizes the points of sealing in the image pickup apparatus of the first embodiment. The imaging device of this example includes a camera case having an opening, a lens group housed in a lens barrel, and a cylindrical pressing member having an opening defined by an annular pressing member, and the pressing member The opening of the pressing member is sealed by the first lens in the lens group by screwing and fixing to the outer peripheral portion of the lens barrel, and the tip of the pressing member fixed by screwing is the camera case. The opening of the camera case is sealed by being housed and fixed in the camera case so as to protrude outward from the opening.

  In the imaging apparatus of this example, the lens group housed in the lens barrel is a wide-angle lens group, and the pressing member has the opening of the pressing member sealed by the first lens in the wide-angle lens group. And the convex surface of the lens is screwed and fixed to the outer peripheral portion of the barrel so that it protrudes outward from the opening of the pressing member, and the inner periphery of the pressing member is the lens group The first lens is arranged so as to extend along the outer peripheral portion of the first lens.

  In the imaging apparatus of the present example, the lens group housed in the lens barrel is a wide-angle lens group, and a step portion is provided on the outer periphery of the pressing member, and the pressing member is the first of the wide-angle lens group. A protrusion provided to form a first step and a second step on a side surface formed between a convex surface on the subject side of the lens and a surface on the imaging side, The first lens is positioned and accommodated in the lens barrel by the second step portion, and the pressing member is a first sealing material disposed on the first step portion of the first lens and the first step. Of the lens barrel so that the opening of the pressing member is hermetically sealed by the lens and the convex surface on the subject side of the first lens protrudes outward of the pressing member from the opening of the pressing member. The holding member screwed and fixed to the outer peripheral portion has its tip attached to the camera. The camera case so that the opening of the camera case is hermetically sealed by the second sealing material that protrudes from the opening of the case and is disposed at the step portion of the pressing member and the pressing member that is screwed and fixed. It is characterized by being housed and fixed in

  In the imaging apparatus of the present example, a sealing material for sealing and sealing is disposed between the pressing member and the first lens, and the pressing member is in a state before being screwed and fixed to the lens barrel. Then, in the state after the clearance between the pressing member and the first lens is larger than the width of the sealing material and the pressing member is screwed and fixed to the lens barrel, the sealing material is pressed and deformed. The clearance has a dimensional relationship to be closed.

  Further, the imaging device of the present example is arranged with a sealing material that hermetically seals between the pressing member and the camera case, and in a state before the pressing member is screwed and fixed to the lens barrel, In a state where the clearance between the pressing member and the camera case is larger than the width of the sealing material and the pressing member is screwed and fixed to the lens barrel, the sealing material is pressed and deformed to close the clearance. It has a dimensional relationship.

  Further, the imaging apparatus of this example includes a camera case having an opening, a wide-angle lens group housed in a lens barrel, a cylindrical pressing member having an opening defined by an annular pressing member, and the pressing member. A step portion provided on the outer periphery, a rising portion having a predetermined diameter provided on the subject side of the first lens in the wide-angle lens group, and an optical axis provided continuously to the rising portion. An orthogonal flat part, and the pressing member presses the flat part of the first lens, and the opening of the pressing member is sealed by the first lens and the first sheet The convex surface of the lens is screwed and fixed to the outer peripheral portion of the lens barrel so that the convex surface of the lens protrudes from the opening of the pressing member. Projecting from the opening of the case and the pressing member Opening of the camera case is characterized in that it is housed and fixed to said camera case in a sealed manner by the section.

In addition, the imaging apparatus of the present example includes a sealing material that is hermetically sealed between the pressing member and the first lens, and a subject of the first lens that is provided at the tip of the pressing member. And a compression ratio of the sealing material by the pressing member is set by contact between the protrusion and the imaging surface of the first lens.
In the imaging apparatus of this example, the diameter of the sealing material is 0.5 mm or more and 3.0 mm or less.
Further, the imaging apparatus of this example is characterized in that the diameter of the sealing material is 0.7 mm or more and 1.4 mm or less.
In the imaging device of this example, the length of the flat portion is 0.7 mm or more. In the imaging apparatus of this example, the rising length of the rising portion is 1.1 mm or more.

  In addition, the imaging apparatus of the present example includes a camera case having an opening, a lens barrel that houses a lens group that is positioned relative to each other, a cylindrical pressing member that surrounds the outer periphery of the lens barrel, and the pressing member And a lens assembly having an opening defined by the first lens in the lens group by screwing and fixing the pressing member to the outer periphery of the lens barrel. The opening of the camera case is sealed by accommodating and fixing the sealed and screwed pressing member in the camera case so that the tip of the pressing member protrudes from the opening of the camera case. It is characterized by that.

  The imaging apparatus of the present example includes the front case having the opening of the camera case and the rear case, and the camera case is configured, and the lens assembly is inserted from the rear of the front case and then screwed from the rear. The front case and the rear case are fixed by screws from the rear side of the rear case, and can be assembled from one direction.

(Modification 1 regarding the first embodiment)
With respect to the first embodiment, a modified example that enables wide-angle imaging while having a hermetic sealing structure using an O-ring will be described.
FIG. 19 is different from the one in which the compression ratio of the O-ring 712 which is the sealing material of FIG. 17 in the first embodiment is managed by the protrusion 710 provided at the tip of the pressing member 705, and the restriction provided on the lens barrel 706. 7 is a diagram illustrating an example of managing the compression ratio of an O-ring 712 by a unit 714. FIG.
In FIG. 19, the same reference numerals as those in FIGS. 16 and 17 indicate the same contents, and thus the description thereof is omitted. Reference numeral 716 denotes a step provided on the pressing member 705 (not shown in FIGS. 16 and 17).

FIG. 19 uses the first lens 700 having the rising portion 721 as in FIG. 17, but as described above, the protrusion 710 that regulates the screwing amount of the pressing member 705 at the tip of the pressing member 705. Not equipped. Instead, in order to prevent the pressing member 705 from being screwed in a predetermined amount or more, the lens barrel 706 is provided with a restricting portion 714 that contacts the lower end surface of the pressing member 705.
The restriction portion 714 restricts the screwing amount of the pressing member 705 to be constant, and as a result, the compression ratio of the O-ring 712 is managed to be constant.
Further, in FIG. 19, a notch 713 is provided at the tip of the pressing member 705. This notch 713 can ensure a wider wide-angle field of view of the first lens 700 than when there is no notch (indicated by a dotted line in FIG. 18). In other words, by providing the notch 713, the rising length of the rising portion 701 of the first lens 700 can be further reduced, and the apparatus can be miniaturized.

In the example shown in FIG. 19, the distance x between the inner peripheral surface of the pressing member 705 and the side surface of the first diameter portion 701 of the first lens 700, the inner peripheral surface of the pressing member 705, and the second of the first lens 700. The distance y from the side surface of the diameter portion 704 is secured wider than that in FIGS.
When the outer periphery of the pressing member 705 protruding from the apparatus receives some external force F due to the spacing between the pressing member 705 and the first lens 700 caused by x and y, only the pressing member 705 is allowed to be deformed. However, it is possible to achieve the effect of reducing the influence of external force on the first lens 700 that is required to maintain accuracy.
Note that the amount of spacing is appropriately set depending on the material of the pressing member 705. Further, it is more preferable to secure both x and y spacing, but it is needless to say that even if one of them is secured, there is a corresponding effect, and this example may secure one. .

(Variation 2 regarding the first embodiment)
With respect to the first embodiment, a modified example that enables wide-angle imaging while having a hermetic sealing structure using an O-ring will be described.
20 is similar to the one in which the compression ratio of the O-ring 712, which is the sealing material of FIG. 17 in the first embodiment, is managed by the protrusion 710 provided at the tip of the pressing member 705. FIG. 20 is a diagram showing a modified example provided with a structure that alleviates a deviation in accuracy of the first lens 700 due to an external force as in the modified example shown in FIG. 19.
In FIG. 20, the same reference numerals as those in FIGS. 16, 17, and 19 indicate the same contents, and thus the description thereof is omitted.
20 has an inclined surface 718 that gently inclines as the object-side tip of the pressing member 705 moves away from the optical axis. Even if any object collides with the pressing member 705 by this inclined surface, the collision can be escaped well by the inclined surface 718 and, of course, the first member is prevented from being destroyed. The effect on 700 can be significantly reduced.

20, as in the example shown in FIG. 19, the distance x between the inner peripheral surface of the pressing member 705 and the side surface of the first diameter portion 701 of the first lens 700 and the inner periphery of the pressing member 705 are the same. The distance y between the surface and the side surface of the second diameter portion 704 of the first lens 700 is secured wider than those in FIGS.
Due to the spacing between the pressing member 705 and the first lens 700 generated by x and y, only the pressing member 705 is deformed when the outer periphery of the pressing member 705 protruding from the apparatus receives some external force F. While allowing, the effect of reducing the influence of external force on the first lens 700 that is required to maintain accuracy can be achieved.
Note that the amount of spacing is appropriately set depending on the material of the pressing member 705. Further, it is more preferable to secure both x and y spacing, but it is needless to say that even if one of them is secured, there is a corresponding effect, and this example may secure one. .

(Variation 3 regarding the first embodiment)
With respect to the first embodiment, a modified example that enables wide-angle imaging while having a hermetic sealing structure using an O-ring will be described.
FIG. 21 differs from that in which the compression ratio of the O-ring 712, which is the sealing material of FIG. 17 in the first embodiment, is managed by the protrusion 710 provided at the tip of the pressing member 705, and is provided on the pressing member 705 itself. It is a figure which shows the example which manages the compression ratio of O-ring 712 by the recessed part 720. FIG.
In FIG. 21, the same reference numerals as those in FIGS. 16, 17, 19, and 20 indicate the same contents, and thus the description thereof is omitted.

FIG. 21 uses the first lens 700 having the rising portion 721 as in FIG. 17, but as described above, the protrusion 710 that regulates the screwing amount of the pressing member 705 at the tip of the pressing member 705. Not equipped. Instead, the compression ratio of the O-ring 712 is managed by the depth z in the optical axis direction of the recess 720 provided in the pressing member 705.
The concave portion 720 includes a slope 719, and the slope 719 can prevent deformation such as twisting of the O-ring 712 when the pressing member 705 is screwed.
Instead of the one shown in FIG. 21, the first lens 700 may be provided with a recess for managing the compression ratio of the O-ring 715 so that the surface of the pressing member 705 that presses the first lens 700 is flat. .

  According to the present invention, it is possible to provide an imaging apparatus with particularly improved environmental resistance.

It is sectional drawing of the imaging device which concerns on embodiment. It is a perspective view of the image pick-up unit concerning an embodiment. It is a front view of the image pick-up unit concerning an embodiment. It is the perspective view which incorporated the imaging unit in the front case concerning an embodiment. It is a disassembled perspective view of the imaging unit concerning an embodiment. It is another disassembled perspective view of the imaging unit which concerns on embodiment. It is AA sectional drawing of the imaging unit which concerns on embodiment. It is sectional drawing of the imaging device main body which concerns on embodiment. It is sectional drawing which sealed the opening of the front case which concerns on embodiment with the pressing member, and sealed the opening of the pressing member with the 1st lens. It is sectional drawing which sealed the opening of the imaging device main body with the 1st lens, and is the state before pressing down with a pressing member. It is sectional drawing which sealed the opening of the imaging device main body with the 1st lens, and is the state after pressing with the pressing member. (A), (b), (c), (d) all show another embodiment corresponding to FIG. (A), (b), (c), (d) all show another embodiment corresponding to FIG. It is a comparative example which shows the advantage of the Example of FIG. It is an effect | action figure which shows the intensity | strength relationship of the lens at the time of sealing with an O-ring, and a pressing member. It is the figure which showed the imaging device of the structure which carried out simple sealing instead of hermetic sealing without using an O-ring. It is a figure explaining that a high wide angle view is realizable, ensuring sufficient sealing performance. It is a figure which shows the result of having performed the differential pressure test by changing the diameter of an O-ring. It is a figure which shows the example which manages the compression ratio of an O-ring by the control part provided in the lens barrel. It is a figure which shows the modification provided with the structure which relieve | moderates the precision deviation of the 1st lens by external force. It is a figure which shows the example which manages the compression ratio of an O-ring with the recessed part provided in pressing member itself.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging device 2 Front case 3 Rear case 10 Imaging unit 20 Imaging device main body 23 1st lens 30 Holding member 32 Lens tube 34, 54 O-ring

Claims (11)

A wide-angle lens group located at least on the incident side among the lens groups arranged on the solid-state imaging device so as to coincide with the optical axis is housed and arranged with the optical axis interval held by a lens barrel, and the wide-angle lens In an imaging apparatus having an imaging apparatus body in which a first lens in the group is formed with a convex surface that forms a light image incident area,
The first lens has a rising portion formed on its outer peripheral surface side so as to extend in parallel with the optical axis toward the convex surface side, and a surface orthogonal to the lens optical axis from the rising portion base side A ring-shaped flat portion with a diameter expanded along the inside,
On the other hand the front side of the lens barrel is fixed to the convex surface of the first sheet of the lens through the barrel locking portion provided at the base side of the lens barrel so as to protrude toward the subject, the 1 A cylindrical pressing member having an opening defined by an annular pressing portion that presses and supports the outer peripheral edge of the lens on the subject side,
A first ring-shaped step portion having a pressing portion formed by enlarging the inner periphery of the pressing member located on the lower side of the annular pressing portion and facing the ring circular flat portion is provided. By pressing the ring-shaped flat part by the pressing part of the ring-shaped step part, the opening of the pressing member is sealed ,
Further, the lens barrel tip side is positioned and held on the lower surface side of the ring-shaped flat portion of the first lens directly or via a second lens so that the lens barrel is not exposed to the subject side. An imaging device that is characterized.   A camera case in which a second ring-shaped step portion on which a seal ring is placed is provided on the outer peripheral side of the pressing member, and the distal end portion side of the pressing member including the convex surface of the first lens houses the imaging device main body The seal ring placed on the second ring-shaped step as if protruding from the opening of the camera presses the support surface on the inner side of the camera case so that the opening of the camera case is sealed. The imaging apparatus according to claim 1, wherein the imaging apparatus is housed and fixed in a case.   2. The imaging apparatus according to claim 1, wherein the pressing portion of the first ring-shaped stepped portion has a surface contact seal structure that makes a liquid-tight seal by contacting the ring circular flat portion by surface contact.   The imaging apparatus according to claim 1, wherein the imaging device has a sealing structure in which a seal ring is interposed between a pressing portion of the first ring-shaped stepped portion and a ring-shaped flat portion to perform liquid-tight sealing.   The seal ring is an O-ring, and an O-ring storage groove is provided on a side of the pressing portion of the first ring-shaped step portion facing the ring circular flat portion, and the height of the O-ring is determined by the storage height of the storage groove. The imaging apparatus according to claim 4, wherein a specified pressure is set.   The seal ring is an O-ring, and a pressing amount regulating surface of the O-ring is provided at a position facing the lens barrel of the pressing member, and the pressing member is locked to the regulating surface so that the prescribed pressing of the O-ring is performed. The imaging apparatus according to claim 4, wherein the imaging apparatus is set.   The seal ring is an O-ring, and an O-ring pressing amount regulating surface is provided on the outer peripheral edge of the convex surface of the first lens, and the pressing member is engaged with the regulating surface to define the O-ring. The imaging apparatus according to claim 4, wherein pressing is set.   The top surface of the annular opening of the pressing member facing the first lens extends in a direction away from the maximum light image incident angle or the maximum light image incident angle of the first lens. The imaging device according to claim 7.   8. The imaging device according to claim 7, wherein the top surface of the annular opening of the pressing member facing the first lens extends at a position lower than the outer peripheral edge of the convex surface of the first lens.   The first lens has two support surfaces formed on its outer peripheral surface side so as to extend in parallel with the optical axis toward the convex surface side, and the first support surface is a support surface for the pressing member. And the second support surface is a support surface for the lens barrel, and the position of each support surface is regulated in a plane perpendicular to the optical axis so as to be movable in the optical axis direction by the counterpart member. The imaging apparatus according to claim 1, wherein: A camera case with an opening;
A wide-angle lens group housed in a lens barrel;
A cylindrical pressing member having an opening defined by an annular pressing portion;
A step provided on the outer periphery of the pressing member;
A rising portion having a predetermined diameter provided on the imaging side of the first lens in the wide-angle lens group, and a flat portion substantially orthogonal to the optical axis provided continuously to the rising portion. ,
The pressing member presses the flat portion of the first lens, the opening of the pressing member is sealed by the first lens, and the convex surface of the first lens is It is screwed and fixed to the outer peripheral portion of the lens barrel so as to protrude outward from the holding member from the opening,
The screwed and fixed pressing member has its tip projecting from the opening of the camera case, and the opening of the camera case is sealed by the step of the pressing member, and the ring circle of the first lens The front end side of the lens barrel is positioned and held on the lower surface of the flat portion of the shape directly or via a second lens, and the lens barrel is configured not to be exposed from the camera case and is housed and fixed in the camera case. An imaging device.

Images