JP2004295119A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an imaging apparatus with an improved environment-resistant function. <P>SOLUTION: The opening of a front case 2 is sealed by a pressing member 30, the opening of the pressing member 30 is sealed by a 1st lens 23. The inside diameter of an O-ring 34 used for sealing the front case 2 is larger than the outside diameter of the 1st lens 23, and the outside diameter of the O-ring 34 is smaller than the inside diameter of the pressing member 30. The O-ring 34 is compressed when the pressing member 30 is screwed in, and a clearance formed by the edge part of the 1st lens 23 and the inner wall surface of the pressing member 30 is sealed by the O-ring with the deformation when pressurized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  2. Description of the Related Art In recent years, along with performance improvements such as miniaturization of imaging elements such as charge-coupled devices (CCDs) and complementary metal-oxide semiconductors (CMOSs), imaging devices for various applications, for example, outdoor applications, have been put into practical use. Such a technique has been proposed.

  Patent Documents 1 to 4 disclose a method in which a ring-shaped projection formed on the periphery of a lens barrel formed of a resin material for housing and holding a lens is thermally welded so as to cover the front side peripheral edge of the first lens. A technique for tightening is disclosed.

  Further, Patent Documents 5 to 8 disclose a technique in which a convex surface of a first convex lens protrudes from a case or the like to secure a wide visual field range for a lens system.

  Non-Patent Documents 1, 8 and 9 disclose techniques used in underwater cameras and the like, in which a first wide-angle lens directly hermetically seals without using a protective glass. It has been disclosed.

  Further, Patent Literatures 10 to 12 disclose techniques for hermetically sealing a case opening with a lens barrel.

JP-A-02-198403 JP-A-11-313235 Japanese Utility Model Laid-Open No. 04-101511 Japanese Patent No. 2679784 JP-A-06-055871 JP-A-02-280107 JP 05-077272 A Japanese Utility Model Laid-Open No. 02-064927 JP-A-09-265035 JP-A-2002-090603 JP 05-241227 A JP 08-029851 A JP 2001-290086 A Japanese Utility Model Publication No. 62-017091 JP-A-2000-175091 Japanese Utility Model Application Laid-Open No. 06-064244 Japanese Utility Model Publication No. 03-006370 JP 05-154102 A JP-A-2002-090603 Japanese Utility Model Publication No. 03-005120 JP-A-2002-098878 JP-A-09-265035 JP-A-03-072789 Japanese Utility Model Registration No. 3084259 JP 2002-139662 A JP-A-2002-098874 JP-A-04-051105 JP-A-63-141011 JP-A-2002-221750 JP 2000-284422 A JP-A-10-133263 Photo Industry, Vol.50, 1992, No.7, P.11-12, New Product Introduction

  However, the above-mentioned proposed technology may not always have sufficient environmental resistance performance such as waterproof performance, and further technical improvement has been desired. The present invention has been made in view of such circumstances, and an object of the present invention is to provide an imaging device with improved environmental resistance and the like.

Therefore, the present invention, in order to solve such a problem,
The aspect of the imaging device of the present invention on the apparatus main body side is such that, of the lens groups arranged on the solid-state imaging device with their optical axes aligned, at least the wide-angle lens group located on the incident side has an optical axis interval by a lens barrel. An image pickup apparatus having an image pickup apparatus main body that is housed and arranged in a state where the position is held, and the first lens of the wide-angle lens group is formed by a convex surface forming an optical image incident area,
The first lens has a rising portion formed on the outer peripheral surface side so as to extend toward the convex surface side in parallel with the optical axis, and a surface perpendicular to the lens optical axis from the rising portion base side. A ring-shaped flat portion whose diameter is enlarged along the inside,
On the other hand, a holding member fixed to the barrel so that the convex surface of the first lens projects toward the subject side via a barrel locking portion provided on the base side of the barrel. The pressing member is provided with a first ring-shaped step portion having a pressing portion formed by expanding a base side of the annular opening so as to face the ring-shaped flat portion; The opening of the holding member is sealed by the pressing of the pressing portion on the ring-shaped flat portion by the pressing portion. Here, the optical axis interval refers to an interval between lenses and the like in the optical axis direction.
The pressing member may be of a screw type, and 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 of the second lens on the subject side.
Further, 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 side surface of the subject of the first lens may be omitted.

Further, in the configuration in which the imaging device body is housed and fixed in a camera case, a second ring-shaped step portion on which a seal ring is mounted is provided on an outer peripheral side of the pressing member, and a convex surface of the first lens is provided. The seal ring placed on the second ring-shaped step portion presses the camera case inner side support surface so that the distal end side of the holding member including the projection protrudes from the opening of the camera case accommodating the imaging device main body. It is preferable that the imaging device main body is housed and fixed in the camera case in a state where the opening is sealed.
For example, the camera case has a front case and a rear case, and after fixing a mechanism including the wide-angle lens group, the lens barrel and the pressing member so as to seal the opening of the front case, the rear surface of the front case is rearward. It may be sealed with a case, and furthermore, a ring-shaped projection is provided on the imaging device main body, and a projection receiving portion is provided on the front case, and the imaging device main body is positioned at a predetermined position of the front case. Is good.

Also, the aspect of the image pickup apparatus of the present invention is a surface contact seal structure in which a pressing portion of the first ring-shaped step portion comes into contact with a ring circular flat portion in surface contact to perform a liquid-tight seal, that is, a hermetic seal. Or a seal structure in which a seal ring is interposed between the pressed portion of the first ring-shaped step portion and the ring-shaped flat portion to perform a liquid-tight seal. In this case, an O-ring is preferably used.
In particular, when the seal ring is an O-ring, the O-ring is not pressed beyond a prescribed pressure, and in order to prevent the O-ring from being damaged, a ring-shaped circular portion of the pressed portion of the first ring-shaped step portion is provided. An O-ring storage groove is provided on the side facing the flat portion, and the specified pressing 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 locked to the regulating surface to set a prescribed pressing force of the O-ring, or furthermore, the pressing amount of the O-ring is formed on the outer peripheral edge of the convex surface of the first lens. It is preferable that a regulating surface is provided, and the pressing member is locked to the regulating surface to set the prescribed pressing of the O-ring.

  Further, when the present invention is used as a waterproof camera for rear monitoring of an automobile, it is necessary to secure a wide viewing angle without obstructing light incident on the first lens. In this case, the top surface of the annular opening of the pressing member extends in the direction of the maximum light image incidence angle (viewing angle) of the first lens or in the retracting direction, or 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.

Further, when the wide-angle lens group holds the position of the optical axis interval by the lens barrel, the optical axis interval is small to achieve miniaturization regardless of the wide viewing angle, so that the optical axis and the plane orthogonal to the optical axis Maintaining accuracy is extremely important.
For this reason, in the present invention, the first lens has two support surfaces formed on the outer peripheral surface side toward the convex surface side so as to extend in parallel with the optical axis. Is a support surface for the holding member, the second support surface is a support surface for the lens barrel, and each of the support surfaces is located in a plane orthogonal to the optical axis so as to be movable in the optical axis direction by a partner member. Regulated.
A camera case having an opening, a wide-angle lens group housed in a lens barrel, a cylindrical holding member having an opening defined by an annular holding portion, and a step provided on the outer periphery of the holding 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 provided substantially continuous with the optical axis and 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 pressed. The holding member is screwed and fixed to the outer peripheral portion of the lens barrel so as to protrude from the opening of the member to the outside of the holding member. The camera case is formed by the step 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 device that is suitably applied in environmental resistance performance such as waterproof performance, and is particularly effective as a rear monitor (a rear view camera) mounted on an automobile.

  Hereinafter, preferred embodiments of the present invention will be illustratively 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, and are merely illustrative examples. Not just.

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 a front case.
As shown in FIG. 1, the imaging apparatus 1 according to the present embodiment includes a front case 2 and a rear case 3, and a packing 4 is inserted between the front case 2 and the rear case 3 to hermetically seal it. As shown, the imaging unit 10 is incorporated in a case. The front case 2 and the rear case 3 are fixed to a boss (not shown) of the front case 2 by a screw inserted from a back surface of the rear case 3 through a hole (not shown) of the rear case 3.

  5 and 6 are exploded perspective views of the imaging unit 10, and FIG. 7 is a 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 foam 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 this order from the subject side.

  The imaging device 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 stop 29 and the third lens 25 to block light rays incident from the effective light rays of the lens. May be.

The first lens 23 has an optical image incident side formed with a convex surface 239, and as shown in the enlarged views of FIGS. 10 and 11, the outer peripheral portion has a step-cut structure. 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 has a diameter enlarged from its base end and a flat surface for mounting the O-ring 34. A ring-shaped step projection 230 having a portion 230a is provided. Further, a second step 232 (second support surface) having a larger diameter than the first step 231 is provided below the ring-shaped step projection 230. The O-ring 34 is provided on a ring-shaped flat portion 230a on the upper surface of the ring-shaped step projection 230, which 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 protruded toward the subject side via a lens barrel screwing portion 302 provided on the inner periphery of the base side. A holding member 30 screwed and fixed to the lens barrel 32 is provided. The holding member 30 causes the lower side 192a of the annular opening 192 set to be narrow toward the outer peripheral edge of the convex surface 239 of the first lens to hang down in the optical axis direction, and the base side thereof to be (rectangular). A first ring-shaped step 310 having a pressing surface 301 facing the ring-shaped flat portion 230a whose diameter has been increased, and the pressing surface 301 of the first ring-shaped step 310 and a 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 by 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 projection 192 of a screw-type pressing member 30 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 surface 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 230a on the upper surface of the ring-shaped step projection 230 of the first lens 23. In addition, as engagement other than screw engagement, fitting, caulking, welding and the like can be exemplified.
Further, the first step portion 231 and the second step portion 232 which are the rising portions are extended on the outer peripheral surface side toward the convex surface side in parallel with the optical axis, so that two supporting 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 holding member 30 and functions as a support surface for the holding member 30, and the second step portion 232 serves as a tip of the lens barrel 32. The diameter is slightly smaller than the step 321 provided on the inner peripheral side, and functions as a support surface for the lens barrel.
As a result, the support surfaces respectively defined by the first step portion 231 and the second step portion 232 are regulated by the mating member so as to be movable in the optical axis direction within a plane orthogonal to the optical axis. The lens holding member 30 and the first lens 23 are hermetically sealed via the O-ring 34, and waterproof performance is obtained. Here, as described later, the rising portion 231 is effective for projecting the lens 23 outward to obtain a wide viewing angle, but can also function as a support surface for the pressing member as described above. .

  In the lens holding member 22 that holds the fourth lens 26, the fifth lens 27, and the sixth lens 28, three key grooves 21 are positioned linearly and equally divide the outer periphery of the lens holding member 22 into three. Provided in a relationship. In this drawing, the keyway 21 is represented by one keyway. In the present embodiment, 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 body 20. The adjustment ring 42 is internally threaded and is freely rotatably fitted to the imaging device body 20.

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

  The lens holder 46 has three keys 47 linearly provided inside the lens holder 46 for key fitting with the three key grooves 21 provided in the lens holding member 22. In this drawing, the key 47 is represented by one key. In the present embodiment, the number is not limited to three and can be provided as appropriate.

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

  When the lens holder 46 is fitted to the imaging device main body 20 and reaches a predetermined position immediately before the focus position in design, 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 pressed by the lens holder 46, the screw portion in which the adjustment ring 42 and the lens holder 46 are fitted and the entire structure of the adjustment ring 42 move in one direction. The adjustment ring 42 is not affected by the backlash of the screw portion and the dimensional change of the storage portion of the adjusting ring 42 due to the dimensional variation of the components.

  A female screw portion 45 is formed in the ring fixing plate 44 so as to be parallel to the outer periphery of the adjusting ring 42. A sharpened ring fixing screw 56 is assembled to the female screw portion 45, and the adjustment ring 42 and the ring fixing plate 44 are integrated, so that the focus is securely fixed. In addition, since the lens barrel 32 is not directly fixed at the time of focusing, a load is not directly applied to the lens. Therefore, no distortion occurs in the lens, and deterioration of the imaging quality can be avoided.

  A CCD substrate 48 provided with a CCD as an image sensor is fixed to the lens holder 46 by third and fourth taptite screws 84 and 86. As described above, the lens holder 46 is key-fitted to the imaging device main body 20, and its position is adjusted by the adjustment ring 42, and by appropriately managing the accuracy of each component, a so-called There is no need for positioning called "vertical alignment" or "tilt adjustment". By mounting the CCD substrate 48 so as to be perpendicular to the lens holder 46, the imaging surface is perpendicular to the optical axis direction. Therefore, when the optical axis direction is the Z-axis direction, the adjustment of the imaging plane may be performed only in the X and Y-axis directions and the rotation direction (θ). The tap tight screw may be a tapping screw or a normal screw depending on the case.

  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 with first and second exterior set screw holes 92 and 94 provided in the imaging device body 20.

  With the above configuration, focus adjustment can be performed without adjusting the lens itself, and the efficiency of the adjustment operation 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 matches a predetermined pixel of the image sensor. Further, since the focus can be fixed by fixing the adjustment ring 42, a load is not directly applied to the lens, and the lens can be prevented from being distorted.

  The imaging device body (lens assembly) 20 will be described in detail. FIG. 8 is a cross-sectional view of the imaging device 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 device 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 provided a rising portion formed by extending the optical axis in parallel and a flat portion for expanding the O-ring from the base end thereof. An O-ring 34 serving as a sealing material is arranged on the flat portion for mounting the O-ring, and the first lens 23 is pressed by the pressing member 30 through the O-ring 34 substantially in the direction of the optical axis OA. . Here, the O-ring 34 is formed of hydrogenated nitrile-butadiene rubber (HNBR). Generally, nitrile-butadiene rubber (NBR) is used for a sealing material of a waterproof camera or the like because of its oil resistance and weather resistance. Furthermore, HNBR, which has improved the ozone resistance, heat resistance, and weather resistance of NBR and extended 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 the contact between the predetermined surface of the first lens 23 on the image plane side and the predetermined surface of the second lens 24 on the subject side.

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

  FIGS. 10 and 11 are enlarged views of a 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 with 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 projection 192 facing inward is provided at an end of the pressing member 30. By screwing the holding member 30 into the lens barrel 32, the O-ring 34 arranged between the first lens 23 and the holding member 30 is pressed and deformed, and the first lens 23 is positioned at the first step portion 231. In this state, the opening of the holding member 30 is hermetically sealed by the first lens 23. At this time, consider the following design considerations.

  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 holding member 30. In this case, as shown in FIG. 10, the O-ring before screwing the holding member 30 into the lens barrel 32 is arranged without being deformed by pressing, and even after screwing the holding member 30 shown in FIG. The O-ring 34 avoids a contact that generates a large frictional force between 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. 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, in optical design, it has been established as common design knowledge that an anti-reflection coating is applied to the first lens on the subject side in order to prevent ghost, flare, and the like due to irregular reflection or back light inside the lens. However, in an imaging apparatus for outdoor use, in a bad environment 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 the photographing is performed. Image quality may be degraded. In addition, cracks in the coating due to thermal expansion cause the same problem. Therefore, in the present embodiment, in the case of an imaging device used in a bad environment, contrary to the conventional design common sense, the coding outside the first lens is abolished, and even in that case, a ghost, a flare, and the like are unlikely to occur. It has a configuration.

  In addition, 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 if it is indoors, or when the first lens is susceptible to a change in environmental temperature.

  The imaging device of the present embodiment that employs a structure in which the opening of the front case 2 is sealed with the pressing member 30 is disclosed in, for example, FIG. The following operational differences are obtained as compared with those having the following structure.

  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 the components and combinations thereof and that such modifications are also within the scope of the present invention. Hereinafter, modified examples 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 varies greatly. If the lens barrel is exposed outside the case, the lens barrel may be distorted, twisted, or deformed due to temperature fluctuation, and the mounting position accuracy of the lens may be reduced. The lens barrel is so sophisticated that a deviation of 1/100 mm or less affects the optical performance.
On the other hand, if the lens barrel is not exposed from the case as in the present embodiment, even if the holding member 30 is slightly deformed, the accuracy of the lens mounting position is not affected. The lens mounting position accuracy is compensated by the lens barrel. In addition, deformation of the lens pressing member 30 due to heat can be further prevented by forming the lens pressing member 30 from a metal material such as an anodized aluminum material or a stainless steel material.

(2) Strength In the case of an outdoor camera, especially a vehicle-mounted camera, force may be applied to the camera portion during car washing or maintenance. When the lens barrel is exposed to the outside, a direct force is applied to the lens barrel and the lens barrel is deformed, which may affect the accuracy of the lens mounting position. On the other hand, if the lens barrel is not exposed from the case as in the present embodiment, a force is rather applied to the pressing member 30, and the force applied to the lens barrel is suppressed, and the deformation of the lens barrel is suppressed. Therefore, the accuracy of the lens mounting position is not easily affected. 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) Chemical resistance Outdoor cameras, especially mounted cameras, are easily exposed to oils and fats such as wax and oil, 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 corrosion of the lens barrel. However, in the present embodiment, since the lens barrel is not exposed from the case, corrosion of the lens barrel is prevented, and the lens mounting position is prevented. Accuracy can be maintained. If the lens holding member 30 is made of the above-described metal material, corrosion can be further prevented.

(4) Tamper resistance Outdoor cameras, especially in-vehicle cameras and the like, need to assume mischief from the outside. If the lens barrel is exposed, a force is directly applied to the lens barrel, causing lens displacement. Further, the first lens may be detached by cutting or peeling off the heat-welded portion with a cutter or the like. On the other hand, in the present embodiment, since the lens barrel is not exposed from the case, the first lens does not come off unless the case is opened, and the durability is excellent. If the lens pressing member 30 is made of the above-mentioned metal material, the tamper resistance is further improved.

(5) Temporal characteristics Each member of the device deteriorates due to a temporal change. In particular, the portion exposed to the outside deteriorates faster than the internal members. In a configuration in which the lens barrel is exposed and the lens is pressed against the lens barrel by thermal welding, there is a concern that the holding portion may be damaged by creep and the lens may come off. On the other hand, in the present embodiment, the lens barrel is not exposed from the case, the first lens is unlikely to come off, and is resistant to aging. If the lens holding member 30 is made of the above-described metal material, the lens holding member 30 is more resistant to aging.

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

(7) Manufacturability In the configuration in which the lens is pressed into the lens barrel by thermal welding, the dimensional variations of all the parts to be fixed by thermal welding overlap, and the height of the lens to be caulked varies, and the caulking strength is reduced. Although it is difficult to keep it constant, in the configuration of the present embodiment, since the fixing of the lens to the lens barrel does not depend on heat, the mounting position of the lens does not depend on the dimensional variation of the parts, and the process control is performed. And yield is advantageous. If the lens pressing member 30 is made of the above-described metal material, the mounting position accuracy of the lens is further improved.

(8) Waterproofing performance In general, when performing hermetic sealing with an O-ring, that is, sealing, the compression rate when the O-ring is pressed and deformed is 8% as a lower limit and 40% as an upper limit. It is preferable to change the control value of the compression ratio according to the diameter of the ring. That is, when the wire diameter is small, the compression rate is increased to increase the contact area, and when the wire diameter is large, the compression rate may be small because it is not necessary to take more contact area than necessary. The compression ratio is generally set in consideration of tolerance and aging.

  On the other hand, according to general publication materials of manufacturers and the like, the waterproofness of the O-ring is 15% to 40% for a wire diameter of 2 mm or less, 10% to 30% for a wire diameter of less than 2 to 4 mm, and a wire diameter of 4 mm. In the above, it is considered that a compression ratio of 8% to 20% is good. In the present embodiment, in consideration of the permanent compression set, a margin of 5% is provided on the high compression side, and the management value of the compression ratio is set to 15% to 35%.

  As described above, the compression ratio must be strictly controlled at the time of hermetic sealing with the 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 formed due to the dimensional variation of the lens components. Since the height of the O-ring fluctuates, it is difficult to secure a certain amount of caulking by the heat welding jig, and as a result, the compression ratio of the O-ring varies, and it is difficult to realize 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 extremely easily managed by managing the screwing amount and the screwing force of the pressing member, so that the yield can be improved and the desired waterproof performance can be provided. .

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

(9) Downsizing In the configuration in which the lens is pressed into the lens barrel by heat welding, as described above, it is difficult to control the compression ratio of the O-ring. Is difficult. On the other hand, according to the configuration of the present embodiment, an O-ring having an extremely small diameter can be employed, and the apparatus can be designed to be smaller. Also in this case, if the lens pressing member 30 is made of the above-described metal material, the compression ratio of the O-ring can be more strictly controlled, which contributes to further downsizing.

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

(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 a case having a different opening dimension, so that the degree of design freedom is high. In addition, by forming the holding member exposed to the outside with the above-described metal or the like, the holding member can be subjected to engraved silk printing or the like, and by performing a decoration process or the like, the appearance can be easily improved. .

  The imaging apparatus according to the present embodiment further has the following differences in operation and effect as compared with those having a structure in which the opening of the front case is sealed with the first lens disclosed in, for example, Patent Documents 10 and 5 described above. Play.

  In the prior art described above, 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 second and subsequent lenses are held and housed in a lens barrel which is also generally formed of resin, but since the lens barrel itself is attached to the front case, the positional accuracy of the second lens and subsequent lenses is reduced. Is deteriorated by the accuracy of the mounting position between the lens barrel and the front case in addition to the accuracy of the lens barrel itself. 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 device with extremely 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 the components and combinations thereof and that such modifications are also within the scope of the present invention.

  For example, FIG. 12A shows a configuration of a main body (lens assembly) of the imaging device for a waterproof camera in which the O-ring 34 is not disposed, in which the space between the first lens 23A and the pressing member 30A is sealed by direct surface contact. 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 pressing surface 301 comes into contact with the ring circular flat portion 230 in surface contact to perform a liquid-tight seal.

  That is, the first lens 23A has a first step portion 231 which is a rising portion formed by forming the light image incident side on the convex surface 239 and extending parallel to the optical axis on the outer peripheral surface edge side of the convex surface 239. (A first support surface) and a ring-shaped stepped projection 230 having a flat portion 230a for mounting the O-ring 34, the diameter of which is enlarged from the base end thereof, and the same as the first stepped portion 231 below the ring-shaped stepped projection 230. A second step portion 232 (second support surface) having a diameter is provided, and the pressing member 30 is brought into surface contact with the ring-shaped flat portion 230a on the upper surface of the ring-shaped step projection 230 to be sealed.

FIG. 12B shows a configuration of the waterproof camera in which the O-ring 34 is arranged. The O-ring is stored on the pressing surface 301 of the first ring-shaped step portion 310 of the pressing member 30B on the side facing the ring-shaped 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 such a configuration, the specified 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 which comes into contact with the ring-shaped flat portion 230a. Prevents collapse.
12A and 12B, since the top surface of the pressing member 30A can be set at a position where the first lens 23A is lower than the outer edge of the convex surface 239, the first lens surface ( Light incident on the convex surface 239) can be prevented from being blocked, and the angle of view can be widened.
In particular, in the configuration of the waterproof camera of FIG. 12B, the pressing surface 301 of the first ring-shaped step portion 310 of the pressing member 30A comes into surface contact with the flat portion 230a of the first lens so as to wrap the O-ring. As a result, the O-ring 34 is not pressed beyond the prescribed pressure, and the O-ring 34 can be prevented from being damaged.

The configuration of the main body of the imaging device for a waterproof camera in FIG. 12C has a regulating portion that supports the base end of the pressing member 30C on the step 322 on the lens barrel tip side and restricts the movement of the pressing member in the optical axis direction. Is what it is.
That is, the base side of the pressing member 30C is screwed into contact with the step 322 of the lens barrel 32C at a position facing the lens barrel of the pressing member to constitute a pressing amount regulating surface of the O-ring 34. The opening edge of the annular opening 192 on the front side of the pressing member 30C is set so as to extend at or above the maximum angle of incidence of the light image of the first lens.

  In the configuration shown in FIG. 12D, the lens barrel tip side is formed so that the base end side of the holding member is housed in the ring-shaped groove 323, and the ring-shaped projection 3011 is expanded on the outer peripheral side surface of the holding member. In this configuration, the movement of the pressing member 30D in the optical axis direction is restricted by making the diameter.

  Therefore, in the configuration of FIGS. 12C and 12D, 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 restricting surface so that the O-ring is locked. Since the specified pressure is set, the O-ring is not pressed more than the specified pressure, and the O-ring can be prevented from being damaged.

FIG. 13 shows another embodiment of the main body of the imaging device for a waterproof camera, in which the first lens 23E is formed so as to extend on the outer peripheral surface side toward the convex surface side in parallel with the optical axis. It has support surfaces 231 and 232, 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 and 23 are provided. 10 and 12 in that the position is regulated by a mating member in a plane orthogonal to the optical axis so as to be movable in the optical axis direction.
In other words, 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 parallel to the optical axis on the outer peripheral surface edge side of the convex surface 239. (A first support surface) and a ring-shaped step protrusion 230 having a flat portion 230a for mounting the O-ring 34 and a first step portion 231 below the ring-shaped step protrusion 230. A small-diameter second step portion 232 (second support surface) is provided, and the holding member 30 is sealed via an O-ring 34 in a ring-shaped flat portion 230 a on the upper surface of the ring-shaped step projection 230.

In this embodiment, the annular opening 192 on the tip 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 face the first step portion 231 (first support surface) in a contact or non-contact manner.
That is, FIG. 13A shows that the peripheral side of the annular opening 192 of the pressing member 30E extends downward in a direction to retract from the optical image incident maximum angle of the first lens 23E. A wide viewing angle is ensured by preventing the incident light from being obstructed by the opening edge, 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 The gap is prevented.
FIG. 13B shows that 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 holding member 30E and the lens barrel 32E, there is a difference in the coefficient of thermal expansion between the first lens 34E, the holding member 30E, and the lens barrel 32E. Even if there is, since the first lens 34 is supported by one or both of the pressing member 30E and the lens barrel 32E, the displacement of the optical axis can be reliably prevented.
The configuration of the imaging device body for a waterproof camera in FIG. 13C is a modified example of FIG. 13B, in which the first lens 24E is formed in a ring shape between the inner wall surface of the pressing member 30E and the first lens. The configuration is different from the configuration in FIG. 13B in that it is supported on the outer peripheral surface of the step protrusion 230 (first support surface).
According to this embodiment, since the first lens 24E is supported by the inner peripheral surface 301 of the holding member 30E, the first lens 23E is held by the opening edge of the annular opening 192 of the holding member in FIG. , It can be strongly supported particularly against radial force.
The configuration shown in 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 adjusted to the incident angle of light incident on the first lens.
Therefore, 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 light incident on the lens, and the shape can be wide. The viewing angle can be ensured, the thickness of the ring-shaped projection 192 of the holding member can be increased within a range that does not narrow the angle of incidence of light incident on the lens, and the strength can be improved. Can be prevented from being damaged by a strong shock.

  That is, as shown in the comparative example of FIG. 14, when the convex surface 239F of the first lens 23F is pressed by the pressing ring 192F of the opening edge of the annular opening 192, a restriction is imposed on the light beam and the maximum necessary condition of the camera for rearward monitoring. , A constraint on the angle of view (the maximum angle of incidence of the 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 first step portion 231 By pressing the surface or the peripheral surface of the ring-shaped protrusion 230, the restriction on the viewing angle can be eliminated. Therefore, according to the present embodiment, a desired viewing angle can be ensured, and the size of the distal end outer diameter, which has many restrictions on the arrangement, can be reduced.

  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 retaining ring must be increased. Then, there is a disadvantage that the angle of view incident on the first lens is necessarily limited, and the wide-angle field of view, which is a feature of the rear monitoring camera, must be sacrificed.

Now, 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 projection 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 be composed of
Therefore, the first step portion 231 is also preferably formed to have a diameter of 0.7 mm or more. Specifically, the first step portion 231 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. You.
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 assumed to be 0.6 mm from the viewpoint of waterproofness, the optical axis direction when the O-ring is crushed is considered. Has a length (crushed diameter X) of 0.435 mm. (Compression rate is calculated at 15%)
When the pressing member 30 is made of molded plastic, the thickness Y and the width Z of the O-ring pressing surface side of the pressing member required to achieve the compression ratio are Z * X> (0.6 / 2). from ² [pi Z> 0.65 is derived, from the Y = √0.91 * Z, Y> 0.7691 is derived.
Therefore, the length S of the rising part in the optical axis direction is
It is understood that S> 0.435 + 0.7691 = 1.2041 mm is the minimum length.

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

Further, the first lens 700 is pressed and fixed to the lens barrel 706 by pressing the flat part 703 of the first lens 700 toward the imaging side by the ring-shaped pressing part 705 arranged on the subject side. The holding member 705 is screwed and fixed to the outer periphery of the lens barrel 706, and a step is provided on the outer periphery of the holding member 705 (not shown). Are projected, and the opening of the camera case is sealed such that the step of the pressing member 705 passes through the opening of the camera case.
Further, the inner periphery of the holding member 705 on the subject side 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. The inner peripheral surface 724 of the holding member 705 is formed over substantially the entire area of the holding member 705.

Here, in the case of an imaging device that requires particularly high sealing performance, it is required that the pressing force for pressing and fixing the first lens 700 to the lens barrel 706 be kept high. For this reason, the holding member 705 that presses the first lens 700 against the lens barrel 706 needs to ensure a large thickness m in order to keep the flat portion 703 of the first lens 700 at 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. Sufficient sealing performance cannot be obtained after a certain period of time.
Therefore, 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 using the first lens 700, the first lens 722 without the rising portion 721 is used, and the holding member 705 having the thickness m, which similarly secures the sealing performance, is used to obtain the wide-angle performance. FIG. 16 shows an example in which is significantly impaired.
The convex surface on the object side of the first lens 722 is shown as a dotted line 722 in FIG. The maximum wide-angle field of view of this imaging device is as shown by line 723. In other words, the light beam having a wider angle than the line 723 is blocked by the side surface 724 of the holding member 705, and the wide field of view is narrowed accordingly. Here, since a 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 having the rising portion 724 is a line 708, and the side surface 724 of the pressing member 705 is compared with the case of the first lens 722 having no rising portion. It is possible to obtain a remarkable wide-angle field of view without being obstructed by light.
That is, by setting the rising portion 724 to have a thickness m equivalent to or more than the thickness of the pressing member 705 sufficient to satisfy the sealing performance, it is possible to secure a sufficient sealing performance and realize a high wide-angle field of view. .

Here, the first lens 700 has a circular shape whose cross section perpendicular to the optical axis is shown as an embodiment. However, according to the present invention, it is possible to form an optical system capable of forming an image of a subject on an image sensor (not shown). Needless to say, the shape may be an elliptical shape or a square shape.
Further, as the first lens 700, the third diameter portion 709 having a diameter larger than the first diameter portion 701 and a smaller diameter than the second diameter portion 704 has been described as an embodiment. It is needless to say that the diameter of the first lens 700 is not limited to the size, 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 in 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). The position may be indirectly determined, such as being stored in the lens barrel 706.

(Detailed description of first embodiment (sealed sealing structure))
Regarding the first embodiment, the point that a wide-angle imaging is enabled while having a hermetically sealed structure using an O-ring as a sealing material will be described in detail.
FIG. 17 shows that the first embodiment, in which the O-rings shown in FIGS. 1 to 11 are hermetically sealed, can realize a high wide-angle field of view while ensuring sufficient hermetic sealing performance. FIG.
Note that, in FIG. 17, those with the same reference numerals as those in FIG. 16 indicate the same contents, and therefore description thereof will be omitted.
FIG. 17 uses the first lens 700 having the rising portion 721 similarly to FIG. 16, but in addition to disposing the O-ring 712 between the flat portion 703 of the first lens 700 and the pressing member 705, The difference from FIG. 16 is that the pressing member 705 for pressing and holding the flat portion 703 of the first lens 700 on the imaging side has a protrusion 701 at the tip on the convex surface 702 side of the first lens 700.

Here, the pressing member 705 is configured to have a suitable thickness m in order to obtain a required required hermetic sealing performance by pressing and holding the flat portion 703 of the first lens 700 via the O-ring 712. ing.
In particular, in the case of an imaging device that requires 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 with an appropriate compression ratio for hermetic sealing. Need to be For this reason, the pressing member 705 that presses the first lens 700 to the lens barrel 706 via the O-ring 712 keeps the flat portion 703 of the first lens 700 at a high pressing force, and also presses the O-ring 712 appropriately. In order to maintain the compression at the compression ratio of, it is necessary to ensure a large wall thickness m. If the wall thickness m is small, the ability to press and hold the first lens 700 is low, or the O-ring 712 cannot be compressed at an appropriate compression ratio, which results in obtaining the desired hermetic sealing performance. Can not. Further, even if sufficient sealing performance is initially obtained, the holding member 705 may be deteriorated due to a change over time, and its pressing and holding ability may be reduced, so that sufficient sealing performance may not be obtained.
Therefore, 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 via the O-ring 712 must have a certain size or more. .

Next, a description will be given of the protrusion 701 of the pressing member 705 that presses and holds the flat portion 703 of the first lens 700 on the imaging side at the tip of the convex surface 702 of the first lens 700.
The projection 701 is the same member as the annular projection 192 shown in FIGS. The projection 701 (projection 192) surely has an effect of abutting against the convex surface 702 of the first lens 700 and pressing the projection surface 702 toward the image pickup side, but actually presses the projection 701 (projection 192). In FIG. 17, the imaging side surface portion 726 of the pressing member 705 that presses and deforms the O-ring 712 at the upper part (subject side) of the O-ring 712 in FIG. For this reason, the main use of the projection 701 (projection 192) is not pressing but setting of the compression ratio of the O-ring 712 described below.
As described above, the O-ring 712 needs to manage the management value of the compression ratio from 15% to 35% in the present embodiment. For this reason, conventionally, when the holding member 705 is screwed and fixed, the amount of screwing of the holding member 705 (the number of rotations for screwing), the amount of movement of the holding member 705 by screwing, and the like are detected in the manufacturing process of the present imaging apparatus, and are defined. The dimension n in FIG. 17 was made constant by screwing up to the detection amount of, and as a result, the compression ratio of the O-ring 712 was controlled.
Here, the detection of the screwing amount and the moving amount is not easy, and unnecessary manufacturing equipment and steps are increased in the manufacturing process, which has a great adverse effect on productivity, yield, and cost.

However, according to the present embodiment, the dimension n is set at a position where the above-described protrusion 710 (the protrusion 192) comes into contact with the convex surface 702 of the first lens 700, that is, the protrusion 710 (the protrusion 192). ) Abuts on the convex surface 702 so that the pressing member 705 cannot be screwed in, by designing the size n of the compression space of the O-ring 712 such that the O-ring 712 is compressed at an appropriate compression ratio. Thus, the compression ratio of the O-ring 712 can be appropriately managed.
Therefore, by simply managing only the screwing torque of the holding member 705, it is not necessary to detect the screwing amount and the moving amount, and it is possible to reduce the number of manufacturing processes, improve the yield, and reduce the number of manufacturing facilities, as compared with the related art. it can.

  Since the projection 710 (projection 192) is not required to have an action of pressing and holding the first lens 700, the above-described thickness m is not necessary, and the projection 710 (the projection 192) can be configured with a relatively small thickness. . Therefore, even though the wide-angle field of view of the first lens 700 is slightly impaired as an open-ended result, as shown by the line 725 indicating the wide-angle field of view shown in FIG. It is evident that

Next, a description will be given of the dimensions of the members of the assembling member that designed the image pickup device for the vehicle according to the present embodiment.
FIG. 18 is generally referred to as a differential pressure test, in which a pressure from a predetermined medium is applied to the front surface of the imaging apparatus according to the present embodiment through the first path, and the reference pressure is applied through the second path. 11 shows the results of a test in which the pressure difference between the two paths when the pressure was applied to the member No. 3 was changed by changing the diameter of the O-ring 712. This test shows that the smaller the differential pressure value on the vertical axis, the better sealing performance can be obtained. In addition, about the same diameter, measurement is performed 5 times.
In general, as a vehicle-mounted imaging device, the above-described differential pressure test is performed five times, and it is required that all of the tests be 10 Pa or less. Therefore, according to FIG. It is necessary to design at least 5 mm. On the other hand, when the diameter of the O-ring 712 is equal to or more than 3.0 mm, the pressing force of the pressing member 705 necessary for setting the compression ratio of the O-ring from 15% to 35% is equal to the second radial portion 704 of the first lens 700. Although it is affected by the thickness, the glass strength of a general optical glass lens exceeds 350 * 10 ⁸ N / m ^2, and it is NG in terms of strength. Therefore, it is preferable that the diameter of the O-ring 712 be 0.5 mm or more and 3.0 mm or less.

  Also, as is apparent from FIG. 18, when the diameter of the O-ring 712 is equal to or greater than 1.4 mm, the measured differential pressure is settled near zero. For this reason, it is not preferable to intentionally select a more expensive O-ring having a diameter of 1.4 mm or more. Further, since the pressing force is required to have a larger value as the diameter becomes larger, it is necessary to increase the strength of the various members. Therefore, there is a concern that the cost of the various members is increased and the size of the entire apparatus is increased.

In addition, if the length l of the flat portion 703 of the first lens 700 is less than the predetermined length, the first lens 700 has a problem that the first lens 700 is liable to be damaged by an impact or the like at the time of manufacturing or transportation. , 0.7 mm or more is required. On the other hand, when the O-ring 712 is pressed and deformed, as shown in FIG. 17, it is better to deform the O-ring 712 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, respectively. Even if it is not in contact, the hermetic sealing performance is improved.
Therefore, it is required that the O-ring 712 be more preferably 0.7 mm or more and 1.4 mm or less.

Here, an example in the case of designing with a 0.6 mm O-ring 712 to make a smaller imaging device will be described. When the compression ratio is controlled at 15%, the thickness n of the O-ring 712 in the optical axis direction becomes 0.435 mm.
The thickness Z of the O-ring 712 in the direction orthogonal to the optical axis (corresponding to l ′ of the flat portion 703) is
Z> 0.65 mm from Z * n> (0.6 / 2) 2π.
Here, the thickness m of the holding member is
m = {0.91 * l '}.
Therefore, the shortest length l required for the rising portion 701 of the first lens 700 is
From 1 = n + m, 1 = 0.435 + 0.7691 = 1.2411 mm.
Therefore, the rising length of the rising portion 701 is more preferably at least 1.2042 mm or more.

  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 shape of the O-ring 712 is designed to be smaller than the inner diameter of the pressing member 705, so that the pressing member 705 is a lens barrel. Even after the screw 706 is screwed, 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 of the first lens 700 and the flat portion 703. It goes without saying that contact that may occur is avoided. As a result, unnecessary frictional force and twisting force in the rotational direction are not generated on the O-ring 712, and the O-ring 712 is not damaged.

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. The holding member 705 may not be provided with a protrusion at the tip end as in the holding member shown in FIG. 16. Further, the amount of screwing of the holding member 705 near the screwing portion of the lens barrel 706 to which the holding member 705 is screwed is fixed. A member for regulating may be provided.
Although an example using an O-ring as the sealing material has been described, the present example is not limited to this, and it is needless to say that a liquid or tape-shaped sealing material may be used.

  Hereinafter, the imaging apparatus according to the first embodiment in which sealing is the point will be summarized. The imaging apparatus 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 opening of the pressing member is sealed by the first lens of the lens group by screwing and fixing to the outer peripheral portion of the lens barrel, and the tip of the screwing and fixing pressing member is the camera case. The camera case is housed and fixed so as to protrude outside from the opening of the camera case, whereby the opening of the camera case is sealed.

  Further, in the imaging apparatus of the present example, the lens group housed in the lens barrel is a wide-angle lens group, and the pressing member has an opening of the pressing member sealed by a first lens of the wide-angle lens group. And, the convex surface of the lens is screwed and fixed to the outer peripheral portion of the lens barrel so that the convex surface protrudes outward from the opening of the pressing member, and the inner periphery of the pressing member is the lens group. Characterized by being arranged to extend along the outer peripheral portion of the first one of the lenses.

  Further, in the imaging apparatus of the present example, the lens group housed in the lens barrel is a wide-angle lens group, a step is provided on the outer periphery of the pressing member, and the pressing member is a first lens of the wide-angle lens group. A projection provided to form a first step and a second step on a side surface formed between the object-side convex surface of the lens and the imaging-side surface; The second lens is positioned and accommodated in the lens barrel by the second step, and the pressing member includes a first sealing material disposed on the first step of the first lens and the first lens. The opening of the holding member is hermetically sealed by the lens, and the convex surface of the first lens on the subject side projects from the opening of the holding member to the outside of the holding member. The holding member screwed and fixed to the outer peripheral portion has The camera case so that the opening of the camera case is hermetically sealed by a second sealing member protruding from an opening of the case and disposed at the step of the holding member and the holding member fixed by screwing. Characterized in that it is housed and fixed in the housing.

  Further, the imaging device of the present example has a state in which a sealing material for hermetically sealing is arranged between the pressing member and the first lens, and the pressing member is not screwed and fixed to the lens barrel. In this case, the clearance between the pressing member and the first lens is larger than the width of the sealing material, and in a state after 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, while disposing a sealing material for hermetically sealing between the pressing member and the camera case, and in a state before screwing and fixing the pressing member to the lens barrel, The clearance between the holding member and the camera case is larger than the width of the sealing material, and in a state after the holding 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 image pickup apparatus of the present example has 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 a pressing member of 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 with the rising portion. An orthogonal flat portion, wherein 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 first The convex surface of the lens is screwed and fixed to the outer periphery of the lens barrel such that the convex surface of the lens protrudes outward from the opening of the holding member. Projecting from the opening of the case, and 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.

Further, the imaging apparatus of the present example includes a sealing member that is disposed between the holding member and the first lens for hermetic sealing, and a subject of the first lens provided at a tip of the holding member. A projection that abuts on a side surface, wherein the compression ratio of the sealing member by the pressing member is set by the abutment between the projection and the imaging surface of the first lens.
Further, the imaging device of the present example is characterized in that the diameter of the sealing material is 0.5 mm or more and 3.0 mm or less.
Further, the imaging device according to the present embodiment is characterized in that the diameter of the sealing material is 0.7 mm or more and 1.4 mm or less.
Further, the imaging device of this example is characterized in that the length of the flat portion is 0.7 mm or more. Further, the imaging device of the present example is characterized in that the rising length of the rising portion is 1.1 mm or more.

  Further, the imaging device of the present example includes a camera case having an opening, a lens barrel that stores the lens groups positioned relative to each other, a cylindrical pressing member that is an outer peripheral portion of the lens barrel, and the pressing member. And a lens assembly having an opening defined by the following. The fixing member is screwed and fixed to an outer peripheral portion of the lens barrel, so that the opening of the pressing member is formed by the first lens in the lens group. By sealing and holding the screwed and fixed holding member in the camera case so that the tip end projects outside from the opening of the camera case, the opening of the camera case is sealed. It is characterized in that.

  Further, the imaging device of the present example comprises a front case having an opening of the camera case, and a rear case, which constitutes the camera case, and after inserting the lens assembly from the rear of the front case, screws from the rear. The front case and the rear case are screwed and fixed from the rear of the rear case so that the front case and the rear case can be assembled from one direction.

(Modification 1 relating to the first embodiment)
Regarding the first embodiment, a modified example that enables wide-angle imaging while having a hermetically sealed structure using an O-ring will be described.
FIG. 19 is different from the first embodiment in which the compression ratio of the O-ring 712 as the sealing material in FIG. 17 is managed by the projection 710 provided at the tip of the holding member 705, and is different from the regulation provided in the lens barrel 706. FIG. 9 is a diagram illustrating an example in which a compression ratio of an O-ring 712 is managed by a unit 714.
Note that in FIG. 19, those with the same reference numerals as in FIGS. 16 and 17 indicate the same contents, and a description thereof will be 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 similarly to FIG. 17, but the protrusion 710 that regulates the amount of screwing of the pressing member 705 on the tip of the pressing member 705 as described above. Not equipped. Instead, in order to prevent the holding member 705 from being screwed by a predetermined amount or more, the lens barrel 706 is provided with a restricting portion 714 in contact with the lower end surface of the holding member 705.
The screwing amount of the pressing member 705 is regulated to be constant by the restricting portion 714, and as a result, the compression ratio of the O-ring 712 is controlled to be constant.
In FIG. 19, a notch 713 is provided at the tip of the holding member 705. The notch 713 can ensure a wider wide-angle field of view of the first lens 700 as compared with a case where there is no notch (shown by a dotted line in FIG. 18). In other words, by providing the cutout portion 713, the rising length of the rising portion 701 of the first lens 700 can be made shorter, and the size of the device can be reduced.

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 The distance y from the side surface of the diameter portion 704 is wider than those shown in FIGS.
Due to the spacing between the pressing member 705 and the first lens 700 caused by x and y, when the outer peripheral portion of the pressing member 705 protruding from the apparatus receives some external force F, only the pressing member 705 is allowed to deform. In addition, the effect of reducing the influence of an external force on the first lens 700 that is required to maintain accuracy can be obtained.
The amount of the spacing is appropriately set depending on the material of the pressing member 705. Further, it is more preferable to secure both x and y spacings, but it is needless to say that securing one of them has a corresponding effect, and that this example may secure one of them. .

(Modification 2 of the first embodiment)
Regarding the first embodiment, a modified example that enables wide-angle imaging while having a hermetically sealed structure using an O-ring will be described.
FIG. 20 illustrates the O-ring 712 by the protrusion 705 in the same manner as the first embodiment in which the compression ratio of the O-ring 712 as the sealing material in FIG. 17 is managed by the protrusion 710 provided at the tip of the pressing member 705. FIG. 20 is a diagram showing a modification provided with a structure for mitigating the irregularity of the accuracy of the first lens 700 due to an external force, similarly to the modification shown in FIG.
20, the same reference numerals as in FIGS. 16, 17, and 19 denote the same contents, and a description thereof will not be repeated.
20 has an inclined surface 718 that is gently inclined as the distal end of the holding member 705 on the subject side moves away from the optical axis. Even if any object collides with the holding member 705 due to the inclined surface, the collision can be successfully escaped on the inclined surface 718 to prevent destruction of the holding member 705 itself. The effect on 700 can be significantly reduced.

20, similarly to 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 peripheral surface of the pressing member 705. The distance y between the surface and the side surface of the second diameter portion 704 of the first lens 700 is wider than those shown in FIGS.
Due to the spacing between the pressing member 705 and the first lens 700 generated by the x and y, only the pressing member 705 is deformed when the outer periphery of the pressing member 705 protruding from the device receives some external force F. The effect of reducing the influence of the external force on the first lens 700, which is required to maintain the accuracy, while allowing it, can be obtained.
The amount of the spacing is appropriately set depending on the material of the pressing member 705. Further, it is more preferable to secure both x and y spacings, but it is needless to say that securing one of them has a corresponding effect, and that this example may secure one of them. .

(Modification 3 of the first embodiment)
Regarding the first embodiment, a modified example that enables wide-angle imaging while having a hermetically sealed structure using an O-ring will be described.
FIG. 21 is different from the first embodiment in which the compression ratio of the O-ring 712 as the sealing material in FIG. 17 is managed by the projection 710 provided at the tip of the holding member 705, and is provided on the holding member 705 itself. FIG. 9 is a diagram illustrating an example of managing a compression ratio of an O-ring 712 by a concave portion 720.
In FIG. 21, the same reference numerals as in FIGS. 16, 17, 19, and 20 denote the same contents, and a description thereof will not be repeated.

FIG. 21 uses the first lens 700 having the rising portion 721 similarly to FIG. 17, but the protrusion 710 that regulates the amount of screwing of the pressing member 705 on the tip of the pressing member 705 as described above. Not equipped. Instead, the compression ratio of the O-ring 712 is controlled by the depth z of the concave portion 720 provided on the pressing member 705 in the optical axis direction.
In addition, the concave portion 720 has 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.
Note that, instead of the one shown in FIG. 21, a concave portion for controlling the compression ratio of the O-ring 715 may be provided in the first lens 700, and the surface of the pressing member 705 pressing the first lens 700 may be flat. .

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

It is a sectional view of an imaging device concerning an embodiment. FIG. 3 is a perspective view of the imaging unit according to the embodiment. FIG. 3 is a front view of the imaging unit according to the embodiment. It is the perspective view which integrated the imaging unit in the front case which concerns on embodiment. FIG. 2 is an exploded perspective view of the imaging unit according to the embodiment. FIG. 4 is another exploded perspective view of the imaging unit according to the embodiment. It is an AA sectional view of an imaging unit concerning an embodiment. FIG. 3 is a cross-sectional view of the imaging device body according to the embodiment. It is sectional drawing which sealed the opening of the front case which concerns on embodiment with a pressing member, and sealed the opening of the pressing member with the 1st lens. FIG. 3 is a cross-sectional view in which the opening of the imaging device main body is sealed with a first lens, which is a state before being pressed by a pressing member. FIG. 4 is a cross-sectional view in which the opening of the imaging device main body is sealed with a first lens, and is a state after being pressed by a pressing member. (A), (b), (c), and (d) all show another embodiment corresponding to FIG. (A), (b), (c), and (d) all show another embodiment corresponding to FIG. 14 is a comparative example showing the advantages of the embodiment of FIG. FIG. 9 is an operation diagram showing a strength relationship between a lens and a pressing member when sealed with an O-ring. FIG. 3 is a diagram illustrating an imaging device having a structure in which sealing is performed without using an O-ring, instead of sealing. It is a figure explaining that a high wide-angle field of view can be realized, ensuring sufficient hermetic sealing performance. It is a figure showing the result of having performed the differential pressure test, changing the diameter of the O ring. FIG. 6 is a diagram illustrating an example in which a compression ratio of an O-ring is managed by a regulating unit provided in a lens barrel. It is a figure which shows the modification provided with the structure which relieves the deviation of the precision of the 1st lens by external force. It is a figure showing the example which manages the compression ratio of the O-ring by the concave part provided in the control member itself.

Explanation of reference numerals

Reference Signs List 1 imaging device 2 front case 3 rear case 10 imaging unit 20 imaging device main body 23 first lens 30 pressing member 32 lens barrel 34, 54 O-ring

Claims (11)

On the solid-state imaging device, among the lens groups arranged with the optical axes aligned, at least the wide-angle lens group located on the incident side is housed and arranged with the optical axis interval maintained by the lens barrel, and the wide-angle lens In an imaging apparatus having an imaging apparatus main body in which a first lens of a group is formed by a convex surface forming an optical image incidence area,
The first lens has a rising portion formed on the outer peripheral surface side so as to extend toward the convex surface side in parallel with the optical axis, and a surface perpendicular to the lens optical axis from the rising portion base side. A ring-shaped flat portion whose diameter is enlarged along the inside,
On the other hand, a holding member fixed to the barrel so that the convex surface of the first lens projects toward the subject side via a barrel locking portion provided on the base side of the barrel. The pressing member is provided with a first ring-shaped step portion having a pressing portion formed by expanding a base side of the annular opening so as to face the ring-shaped flat portion; An image pickup device, wherein an opening of a pressing member is sealed by pressing a ring-shaped flat portion by the pressing portion of the step portion.   A camera case in which a second ring-shaped step portion on which a seal ring is mounted is provided on an outer peripheral side of the pressing member, and a distal end side of the pressing member including a convex surface of the first lens accommodates an imaging device main body. When the seal ring placed on the second ring-shaped step portion as if protruding from the opening of the camera case presses the inner side support surface of the camera case and the opening of the camera case is sealed, the imaging device main body is The imaging device according to claim 1, wherein the imaging device is housed and fixed in a case.   2. The imaging device according to claim 1, wherein the pressing portion of the first ring-shaped step portion has a surface contact seal structure in which a liquid-tight seal is performed by making a surface contact with the ring circular flat portion.   2. The image pickup apparatus according to claim 1, wherein the image pickup apparatus has a seal structure that performs a liquid-tight seal by interposing a seal ring between a pressing portion of the first ring-shaped step portion and a ring-shaped flat portion.   The seal ring is an O-ring, and an O-ring receiving groove is provided on a side of the pressing portion of the first ring-shaped step portion facing the ring-shaped flat portion, and the O-ring is formed by the storing height of the storing groove. The imaging device according to claim 4, wherein the specified pressure is set.   The sealing 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 restricting surface to reduce the specified pressing of the O-ring. The imaging apparatus according to claim 4, wherein the setting is set.   The seal ring is an O-ring, and a pressing amount regulating surface of the O-ring is provided on an outer peripheral edge of the convex surface of the first lens, and the pressing member is locked to the regulating surface to define the O-ring. The imaging device 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 incidence angle of the first lens or the maximum light image incidence angle. The imaging device according to claim 7.   8. The imaging apparatus according to claim 7, wherein an annular opening top surface of the pressing member facing the first lens extends at a position lower than an outer peripheral edge of the convex surface of the first lens.   The first lens has, on its outer peripheral surface side, two support surfaces formed so as to extend parallel to the optical axis toward the convex surface side, and the first support surface is a support surface for the pressing member. And that the second support surface is a support surface for the lens barrel, and that the respective support surfaces are movably moved in the optical axis direction by a mating member in a position orthogonal to the optical axis. The imaging device according to claim 1, wherein: A camera case with an opening,
A wide-angle lens group housed in the lens barrel,
A cylindrical holding member having an opening defined by an annular holding portion,
A step provided on the outer periphery of the holding 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 provided substantially continuous with the optical axis and 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 from the opening to the outside of the holding member,
The holding member screwed and fixed was housed and fixed to the camera case so that the tip end protruded from the opening of the camera case, and the opening of the camera case was sealed by the step portion of the holding member. An imaging device characterized by the above-mentioned.

Images