JP2010134379A - Lens unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens unit in which a lens and a lens barrel are stuck and fixed by using a photosetting adhesive, and positional deviation or eccentricity or the like of the lens is hardly caused. <P>SOLUTION: A through-hole 56 is formed on a circumference surface of the lens barrel 5 so as to communicate with a circumference surface 14 of a first infrared lens 1 held by a lens holding part 51 of the lens barrel 5. A through-hole 55 is formed on the circumference surface of the lens barrel 5 so as to communicate with a contact part between a spacer 7 and a second infrared lens 2 inserted and fitted in the lens barrel 5 and positioned by the spacer 7. A recess 71 is formed at the contact part between the spacer 7 and the infrared lens 2 on the spacer 7, and the through-hole 55 of the lens barrel 5 is formed to communicate with the recess 71 of the spacer 7. By pouring the photosetting adhesive from the through-holes 55 and 56, and irradiating the adhesive with ultraviolet rays from the outside of the lens barrel 5, the photosetting adhesive is cured, so that the first infrared lens 1 and the second infrared lens 2 are stuck and fitted in the lens barrel 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens unit configured by inserting a plurality of infrared lenses into a lens barrel and bonding and fixing the infrared lens to the lens barrel with an adhesive.

  An imaging apparatus generally includes a lens unit, and the lens unit has a configuration in which a plurality of lenses are inserted into a substantially cylindrical barrel. When assembling the lens unit, insert a plurality of lenses in the lens barrel in sequence, align the lens (align the center axis of the lens), and then use an adhesive to bond and fix the lens to the lens barrel. Done in When a slight misalignment or decentration occurs between the lenses, the optical performance of the lens unit is significantly reduced. Therefore, it is necessary to accurately align the lens, and the misalignment or decentering of the lens occurs after assembly. To prevent this, the lens and the lens barrel must be securely bonded and fixed. As the adhesive for fixing the lens and the lens barrel, a photo-curing adhesive that is cured by irradiation with ultraviolet rays is often used. By using a photocurable adhesive, there is an advantage that the lens and the lens barrel can be bonded and fixed in a short time and with high accuracy.

  In Patent Document 1, a plurality of protrusions project from the outer peripheral surface of the lens or the inner peripheral surface of the lens frame, and the protrusions are fitted to the inner peripheral surface of the lens frame or the outer peripheral surface of the lens. In addition, a lens holding device having a configuration in which a lens is fixedly held in a lens frame by interposing an adhesive between gaps formed on the inner peripheral surface of the lens frame has been proposed. This lens holding device can reliably prevent the adhesive from protruding into the effective diameter of the lens when the lens is fixedly held via the adhesive. In addition, since the radial positioning of the lens can be performed by the protrusions and the centers of the lens and the lens frame can be matched, the quality and reliability of the lens system can be improved.

In recent years, infrared imaging devices that perform infrared imaging have become widespread. For example, a night vision system has been put into practical use in which an infrared imaging device is mounted on a vehicle to image the surroundings of the vehicle at night, detect pedestrians that may collide, and issue a warning to the driver. An infrared imaging device performs imaging by including an infrared lens that transmits and condenses infrared rays and an infrared imaging element that receives infrared rays.
Japanese Patent Laid-Open No. 2-110503

  However, the infrared lens included in the infrared imaging device is made of a material such as germanium (Ge), zinc sulfide (ZnS), zinc selenide (ZnSe), or chalcogenide glass, and transmits infrared rays, but ultraviolet rays and visible rays. The transmittance of is low. Further, the lens barrel of the lens unit is formed of a metal such as an aluminum alloy or a synthetic resin, and does not transmit ultraviolet rays. Therefore, since the ultraviolet rays cannot be transmitted through the lens unit, the lens unit of the infrared imaging device has a problem that the infrared lens and the lens barrel cannot be bonded and fixed using a photocurable adhesive.

  For this reason, in the lens unit of the infrared imaging device, a thermosetting adhesive is used to fix the infrared lens and the lens barrel. However, thermosetting adhesives take a long time to cure, and there is a risk of misalignment or eccentricity when the adhesive is cured due to the difference in thermal expansion between the infrared lens and the lens barrel. There is a problem that workability is lowered and accuracy of alignment of the infrared lens is lowered.

  The lens holding device described in Patent Document 1 has a configuration in which an adhesive is applied between the lens outer peripheral surface and the lens frame inner peripheral surface generated by the protrusion, and can be cured by irradiating the adhesive with ultraviolet rays. The lens and the lens frame can be bonded and fixed using an ultraviolet curable adhesive. However, this lens holding device has a configuration in which the outer peripheral surface of the lens and the inner peripheral surface of the lens frame are in contact with each other only at the protruding end of the projection, so that even after the adhesive is cured, the lens is displaced or decentered. Etc. are likely to occur.

  The present invention has been made in view of such circumstances, and an object of the present invention is to be able to bond and fix a lens and a lens barrel using a photo-curing adhesive, so that the lens is misaligned or decentered. The object is to provide a lens unit that is unlikely to cause such problems.

  The lens unit according to the present invention includes a plurality of infrared lenses, a lens barrel in which the infrared lenses are inserted, and a cylindrical spacer that is interposed between the plurality of infrared lenses and fits in the lens barrel. In the lens unit comprising: a through-hole communicating with the peripheral surface of the infrared lens inserted into the lens barrel and / or a portion of the spacer that contacts the infrared lens. Is formed.

  The lens unit according to the present invention is characterized in that the spacer has a recess formed in a portion where the infrared lens contacts, and the through hole is formed to communicate with the recess. .

  In addition, the lens unit according to the present invention includes a cover member that covers the through hole.

  The lens unit according to the present invention includes a lens holder that is fixed to the lens barrel, abuts on a peripheral portion of the infrared lens disposed on the outermost side in the axial direction of the lens barrel, and presses the infrared lens. The cover member is provided integrally with the lens presser.

  The lens unit according to the present invention is characterized in that a plurality of the through holes are formed at equal intervals in the circumferential direction of the lens barrel.

In the present invention, a through hole is formed on the peripheral surface of a lens barrel into which an infrared lens is inserted. The through hole is formed so as to communicate with the peripheral surface of the infrared lens inserted into the lens barrel. In addition, the through hole is formed so as to communicate with a portion of the spacer that contacts the infrared lens of the spacer that is positioned between the plurality of lenses in the lens barrel.
As a result, since the through hole is exposed to the outside, the photocurable adhesive is poured into the through hole and applied, and the photocurable adhesive is applied by irradiating ultraviolet rays from the outside of the lens barrel into the through hole. The infrared lens and the lens barrel and / or the spacer can be bonded and fixed.

  In the present invention, the cylindrical spacer is in contact with the infrared lens at its end surface, but the spacer is formed with a recess in the portion in contact with the infrared lens. Further, the through hole of the lens barrel is formed so as to communicate with the concave portion of the spacer. As a result, the photocurable adhesive can be poured from the through hole of the lens barrel into the recess of the spacer and cured. Further, since the concave portion of the spacer is formed in a portion that contacts the infrared lens, the infrared lens can be bonded and fixed to the spacer and the lens barrel by curing the adhesive poured from the through hole.

  In the present invention, the lens unit includes a cover member for covering the through hole of the lens barrel. Thereby, it is possible to prevent unnecessary light from entering the lens barrel from the through hole and degrading the optical performance of the lens unit.

  Further, in the present invention, the lens presser that holds the outermost infrared lens is fixed to the lens barrel and abuts against the peripheral portion of the infrared lens disposed in the outermost axial direction in the lens barrel. The unit is equipped. Further, a cover member that covers the through hole of the lens barrel is provided integrally with the lens holder. Thereby, since the number of components of the lens unit can be reduced, it is possible to reduce the number of assembling steps and the cost.

  In the present invention, a plurality of the above-described through holes are formed on the peripheral surface of the lens barrel, and the plurality of through holes are arranged at equal intervals in the circumferential direction. As a result, it is possible to efficiently and firmly bond and fix the lens barrel and the infrared lens.

  In the case of the present invention, an infrared ray is formed by forming a through-hole in the peripheral surface of the lens barrel so as to lead to the peripheral surface of the infrared lens inserted into the lens barrel and / or to the portion of the spacer that contacts the infrared lens. After the lens is inserted into the lens barrel, a photocurable adhesive can be poured into the through hole, and the photocurable adhesive in the through hole can be cured by irradiating with ultraviolet rays. Therefore, after aligning the infrared lens at the time of assembling the lens unit, the infrared lens and the lens barrel can be quickly bonded and fixed using the photocurable adhesive. Since there is no need for heating, there is no possibility that the infrared lens is displaced or decentered due to a difference in thermal expansion. In addition, since the ratio of the opening portion of the through hole to the peripheral length of the inner peripheral surface of the lens barrel or the infrared lens may be small, the peripheral surface of the infrared lens is brought into close contact with the inner peripheral surface of the lens barrel. And can be firmly fitted.

(Embodiment 1)
Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. 1 is a perspective view showing the configuration of a lens unit according to Embodiment 1 of the present invention, FIG. 2 is an exploded perspective view showing the configuration of the lens unit, and FIG. 3 shows the configuration of the lens unit. It is sectional drawing.

  The lens unit according to Embodiment 1 of the present invention includes a first infrared lens 1, a second infrared lens 2, a lens barrel 5, a lens holder 6, and a spacer 7, and the first infrared lens 1 is attached to the lens barrel 5. The spacer 7 and the second infrared lens 2 are sequentially inserted, and the lens holder 6 is fixed to one end of the lens barrel 5. In the following, with respect to the axial direction of the lens barrel 5, the second infrared lens 2 side (upper side in FIG. 3) is referred to as the front side, and the first infrared lens 1 side (lower side in FIG. 3) is referred to as the back side.

  The first infrared lens 1 and the second infrared lens 2 are manufactured using zinc sulfide, germanium, chalcogenide glass, or the like as a raw material, and are, for example, lenses that transmit infrared rays in the 8 to 12 μm band. The first infrared lens 1 has a disc shape, and is a so-called meniscus lens having a convex surface 11 on the front side and a concave surface 12 on the back side. Further, the first infrared lens 1 has a flange portion 13 in which peripheral portions of the front and back surfaces are formed smoothly, and the flange portion 13 is a portion for holding the first infrared lens 1 in the lens barrel 5. .

  Similarly, the second infrared lens 2 is a meniscus lens having a disk shape, having a convex surface 21 on the front side and a concave surface 22 on the back side. The second infrared lens 2 has a flange portion 23 in which peripheral portions of the front and back surfaces are formed smoothly, and the flange portion 23 is a portion for holding the second infrared lens 2 in the lens barrel 5. The second infrared lens 2 is larger in diameter and thicker than the first infrared lens 1. Therefore, with respect to the axial direction, the width of the peripheral surface 24 of the second infrared lens 2 is larger than the width of the peripheral surface 14 of the first infrared lens 1.

  The lens barrel 5 has a cylindrical shape, and is manufactured using, for example, an aluminum alloy. The diameter of the first infrared lens 1 is smaller than the inner diameter of the lens barrel 5, and a lens holding portion 51 for holding the first infrared lens 1 is formed in the lens barrel 5. The lens holding part 51 has an annular shape that protrudes from the inner peripheral surface of the rear side end of the lens barrel 5 over the entire circumference, and has a stepped shape in which the inner diameter gradually decreases from the front side to the rear side. It is. The lens holding part 51 has a part in contact with the peripheral surface 14 of the first infrared lens 1 and a part in contact with the back surface of the flange 13 of the first infrared lens 1, and the first infrared lens 1 is attached from the front side. The first infrared lens 1 is fitted and held in the lens holding part 51 of the lens barrel 5 by being inserted into the lens barrel 5 and bringing the peripheral surface 14 and the back surface of the collar part 13 into contact with the lens holding part 51. The

  In the state in which the first infrared lens 1 is fitted and held in the lens holding portion 51, a part of the front side of the peripheral surface 14 is exposed from the lens holding portion 51, and the exposed portion and the lens barrel 5 A gap A is provided between them. A through-hole 56 that penetrates in the radial direction of the lens barrel 5 is formed on the inner peripheral surface of the lens barrel 5 so as to face the exposed portion of the peripheral surface 14 of the first infrared lens 1. The through hole 56 is formed so as to communicate with the gap A between the first infrared lens 1 and the lens barrel 5, that is, formed in the lens barrel 5 so as to communicate with the peripheral surface 14 of the first infrared lens 1. ing. The lens barrel 5 has three through holes 56 formed at equal intervals in the circumferential direction.

  The spacer 7 has a cylindrical shape, and is manufactured using, for example, an aluminum alloy like the lens barrel 5. The outer diameter of the spacer 7 is substantially the same as the inner diameter of the lens barrel 5, and the spacer 7 can be inserted and fitted into the lens barrel 5 from the front side. Further, the inner peripheral surface of the spacer 7 is formed in a tapered shape whose inner diameter gradually decreases from the front side to the back side. In the lens barrel 5, the end surface on the back side of the spacer 7 contacts the front surface of the flange portion 13 of the first infrared lens 1, and the end surface on the front side of the spacer 7 contacts the back surface of the flange portion 23 of the second infrared lens 2. Touch. That is, the spacer 7 is interposed between the first infrared lens 1 and the second infrared lens 2, whereby the first infrared lens 1 and the second infrared lens 2 are positioned.

  The outer diameter of the spacer 7 is larger than the outer diameter of the first infrared lens 1, and a part of the outer edge side of the end surface on the back side of the spacer 7 does not come into contact with the flange portion 13 of the first infrared lens 1. Therefore, when the spacer 7 is inserted into the lens barrel 5, the outer edge side of the end surface on the back side faces the gap A between the peripheral surface 14 of the first infrared lens 1 and the inner peripheral surface of the lens barrel 5. Block from the side. Accordingly, the gap A is surrounded by the inner peripheral surface of the lens barrel 5, the front surface of the lens holding portion 51, the peripheral surface 14 of the first infrared lens 1, and the end surface on the back surface side of the spacer 7, and only through the three through holes 56. The structure communicates with the outside of the cylinder 5.

  After the first infrared lens 1 and the spacer 7 are inserted and fitted into the lens barrel 5, a photocurable adhesive is poured from the outside of the lens barrel 5 into the gap A in the lens barrel 5 through the through hole 56, The photo-curing adhesive is cured by irradiating with ultraviolet rays through 56. Accordingly, the first infrared lens 1 is bonded and fixed to the inner peripheral surface of the lens barrel 5 and the end surface on the back side of the spacer 7.

  The inner diameter of the lens barrel 5 is formed to be approximately equal to or slightly larger than the outer diameter of the second infrared lens 2, and the second infrared lens 2 can be inserted into the lens barrel 5 from the front side and fitted. In addition, after the first infrared lens 1 and the spacer 7 are inserted into the lens barrel 5, the second infrared lens 2 is inserted into the lens barrel 5, and the back surface of the flange portion 23 of the second infrared lens 2 is attached to the spacer 7. In the contacted state, the axial lengths of the lens barrel 5 and the spacer 7 are adjusted so that a part of the peripheral surface 24 of the second infrared lens 2 is exposed from the lens barrel 5. Thus, after the second infrared lens 2 is inserted into the lens barrel 5, the peripheral surface 24 of the second infrared lens 2 exposed from the lens barrel 5 is gripped by a jig or the like, and the second infrared lens 2 intersects the central axis. The alignment operation can be performed by moving or rotating on the plane to be rotated.

  In addition, a recess 71 is formed in the outer edge portion of the front end surface of the spacer 7 that contacts the second infrared lens 2. The recess 71 is a mode in which the outer edge portion of the front end surface of the spacer 7 and the front end portion of the outer peripheral surface are recessed, and three recesses 71 are formed at equal intervals in the circumferential direction of the spacer 7. In the lens barrel 5, three through holes 55 that penetrate in the radial direction are formed at equal intervals in the circumferential direction of the lens barrel 5 so as to communicate with the three recesses 71 of the spacer 7. Therefore, when the spacer 7 and the second infrared lens 2 are inserted and fitted into the lens barrel 5, the front surface of the recess 71 formed in the spacer 7 is blocked by the flange portion 23 of the second infrared lens 2. At the same time, it communicates with the outside of the lens barrel 5 only through the through hole 55.

  After the spacer 7 and the second infrared lens 2 are inserted and fitted into the lens barrel 5, the photo-curing adhesive is applied from the outside of the lens barrel 5 to the recess 71 formed in the spacer 7 in the lens barrel 5 through the through hole 55. The agent is poured and cured by irradiating the photocurable adhesive in the recess 71 with ultraviolet rays through the through hole 55. Thus, the second infrared lens 2 is bonded and fixed to the front end face of the spacer 7 (and the inner peripheral surface of the lens barrel 5).

  Although not shown, a thread groove is formed in the vicinity of the front side end portion of the outer peripheral surface of the lens barrel 5, and the mirror groove 5 is screwed into the thread groove formed on the inner peripheral surface of the lens holder 6. The cylinder 5 and the lens holder 6 can be fixed. The lens retainer 6 is provided in a cylindrical part 61 in which a thread groove to be screwed into a thread groove of the lens barrel 5 is formed on the inner peripheral surface, and from the front side end of the cylindrical part 61 toward the inside. 5, and a pressing portion 62 that contacts the flange portion 23 of the second infrared lens 2 that is inserted into the opening 5. The pressing portion 62 has an opening 63 for exposing the convex surface of the second infrared lens 2. . By screwing the lens holder 6 into the lens barrel 5, the second infrared lens 2 is sandwiched between the pressing portion 62 of the lens holder 6 and the front side end face of the spacer 7 in the axial direction and firmly fixed.

  When assembling the lens unit, first, the first infrared lens 1 is inserted into the lens barrel 5 and held by being fitted to the lens holding portion 51, and the spacer 7 is held on the back side end surface of the first infrared lens 1. Insert and fit until it comes into contact with the flange 13. At this time, the circumferential position of the spacer 7 is adjusted so that the through hole 55 of the lens barrel 5 and the recess 71 of the spacer 7 are at the same position. Thereafter, a photocurable adhesive is poured into the gap A between the lens barrel 5, the first infrared lens 1 and the spacer 7 from the through hole 56 of the lens barrel 5, and is cured by irradiating with ultraviolet rays.

  Next, the second infrared lens 2 is inserted into the lens barrel 5 until it comes into contact with the spacer 7, and the second infrared lens 2 is aligned. After completion of the alignment operation, a photo-curable adhesive is poured from the through hole 55 of the lens barrel 5 into the recess 71 of the spacer 7 and is cured by irradiating with ultraviolet rays. Next, the lens holder 6 is screwed to the front side of the lens barrel 5 to complete the assembly of the lens unit. The first infrared lens 1, the spacer 7, and the second infrared lens 2 are inserted into the lens barrel 5, and the lens holder 6 is screwed into and fixed to the lens barrel 5, and then light-cured to the through holes 55 and 56. The lens unit may be assembled by a procedure in which an adhesive is poured and cured. Further, the lens holder 6 may be bonded and fixed to the lens barrel 5.

  The lens unit having the above configuration communicates with the peripheral surface 14 of the lens barrel 5 into which the first infrared lens 1 and the second infrared lens 2 are inserted, and communicates with the peripheral surface 14 of the first infrared lens 1. By forming the through holes 55 and 56 so as to communicate with the contact portion between the lens 2 and the spacer 7, after the first infrared lens 1 and the second infrared lens 2 are aligned, the through holes 55 and 56 are formed. The photo-curing adhesive can be poured through, and the photo-curing adhesive can be cured by irradiating ultraviolet rays from the peripheral surface of the lens barrel 5 through the through-holes 55 and 56. Therefore, a heat-curing adhesive that requires heating is used. The first infrared lens 1 and the second infrared lens 2 can be quickly bonded and fixed to the lens barrel 5 using a photo-curing adhesive. There is no possibility that the first infrared lens 1 and the second infrared lens 2 are displaced or decentered due to the difference in thermal expansion, and the first infrared lens 1 and the second infrared lens 2 can be fixed with high accuracy. The optical performance and reliability of the unit can be improved.

  Further, the through hole 56 of the lens barrel 5 is formed on the inner peripheral surface of the lens barrel 5 facing the peripheral surface 14 of the first infrared lens 1 held by the lens holding portion 51, that is, the through hole is formed in the first infrared lens. By being formed so as to communicate with one peripheral surface 14, the first infrared lens 1 is surrounded by the peripheral surface 14, the end surface on the back side of the spacer 7, the inner peripheral surface of the lens barrel 5, and the front surface of the lens holding portion 51. The photocurable adhesive can be poured into the gap A to be cured, and the first infrared lens 1 can be quickly and reliably bonded and fixed to the lens barrel 5 and the spacer 7.

  In addition, a recess 71 is formed on the front end surface of the spacer 7 (that is, a portion in contact with the second infrared lens 2), and a through hole 55 is formed in the lens barrel 5 so as to communicate with the recess 71. The photocurable adhesive can be poured into the concave portion 71 through 55 to be cured, and the second infrared lens 2 can be quickly and reliably bonded and fixed to the spacer 7 and the lens barrel 5.

  In the present embodiment, the three through holes 55 are formed in the lens barrel 5, but the present invention is not limited to this, and two or less or four or more through holes 55 are formed in the lens barrel 5. May be. The same applies to the through hole 56. Moreover, although it was set as the structure which inserts two lenses, the 1st infrared lens 1 and the 2nd infrared lens 2, in the lens-barrel 5, it does not restrict to this but inserts three or more lenses in a lens-barrel. It may be a configuration. Further, although a part of the peripheral surface 24 of the second infrared lens 2 is exposed from the lens barrel 5, the present invention is not limited to this, and the configuration may be such that the peripheral surface 24 is entirely contained in the lens barrel 5. . In addition, the lens holder 6 is fixed by being screwed to the lens barrel 5, but the present invention is not limited to this. The lens holder 6 is externally fitted to the lens barrel 5 and fixed by an adhesive or the like. It may be.

(Embodiment 2)
FIG. 4 is a cross-sectional view showing a configuration of a lens unit according to Embodiment 2 of the present invention. The lens unit according to Embodiment 1 has a configuration in which a through hole 55 formed in the lens barrel 5 is exposed to the outside. On the other hand, the lens unit according to Embodiment 2 is configured to include a member that covers the through-hole 55 after the photocurable adhesive poured into the through-hole 55 is cured by irradiating with ultraviolet rays.

  The lens unit according to Embodiment 2 includes a lens holder that is screwed with a screw groove formed in the vicinity of the front end of the outer peripheral surface of the lens barrel 205 and a screw groove formed on the inner peripheral surface of the lens holder 206. The configuration is such that 206 is fixed to the lens barrel 205, but the through-hole 55 for pouring the photo-curing adhesive is formed in the portion of the lens barrel 5 where the thread groove is provided. Thus, after the photocurable adhesive is poured into the through hole 55 and cured, the lens holder 206 is screwed into the lens barrel 205 and fixed, so that the through hole 55 covers the cylinder part 261 of the lens holder 206. Hidden.

  The lens unit according to Embodiment 2 having the above-described configuration is configured to use the cylindrical portion 261 of the lens holder 206 as a cover member for covering the through-hole 55, thereby allowing the through-hole 55 to pass from the outside of the lens barrel 205. Since unnecessary light can be prevented from entering the inside, the optical performance of the lens unit can be prevented from deteriorating. Further, since the cover member is provided integrally with the lens presser 206, there is no increase in the number of parts of the lens unit, an increase in the number of assembly steps, and the like. Further, it is possible to prevent the aesthetic appearance of the lens unit from being obstructed by exposing the through hole 55 formed in the lens barrel 205.

  In addition, since the other structure of the lens unit which concerns on Embodiment 2 is the same as that of the lens unit which concerns on Embodiment 1, the same code | symbol is attached | subjected to the same location and detailed description is abbreviate | omitted.

(Modification)
FIG. 5 is a cross-sectional view showing a configuration of a lens unit according to a modification of Embodiment 2 of the present invention. The lens unit according to Embodiment 2 has a configuration in which the through hole 55 formed on the front side of the lens barrel 205 is covered with the cylinder portion 261 of the lens holder 206, and the through hole 56 on the back side is exposed to the outside. State. On the other hand, the lens unit according to the modification includes a cover member 209 for covering the through hole 56 formed on the back side of the lens barrel 205a.

  The cover member 209 has a cylindrical shape, and a screw groove is formed on the inner peripheral surface thereof although not shown. A screw groove that is screwed into the screw groove of the cover member 209 is formed in the vicinity of the rear end portion of the outer peripheral surface of the lens barrel 205a, and the through hole 56 for pouring the photocurable adhesive is provided in the lens barrel 5. Is formed in a portion provided with a screw groove on the back side. Thus, after the photocurable adhesive is poured into the through hole 56 and cured, the cover member 209 is screwed from the back side of the lens barrel 205a and fixed, so that the through hole 56 is covered with the cover member 209. It is.

  In the lens unit according to the modification of the second embodiment having the above-described configuration, the cover member 209 is screwed into the lens barrel 205a so as to cover the through-hole 56, so that the through-hole 56 from the outside of the lens barrel 205a. Since unnecessary light can be prevented from being incident on the inside through the lens unit, it is possible to prevent the optical performance of the lens unit from being deteriorated.

(Embodiment 3)
FIG. 6 is a cross-sectional view showing a configuration of a lens unit according to Embodiment 3 of the present invention. The lens units according to Embodiments 1 and 2 have a through hole 55 that communicates with the recess 71 formed in the spacer 7, and a through hole that communicates with the gap A between the peripheral surface 14 of the first infrared lens 1 and the inner peripheral surface of the lens barrel 5. 56 is formed in the lens barrel 5. On the other hand, in the lens unit according to the third embodiment, no recess is formed in the spacer 307, and the positions of the through holes 355 and 356 formed in the lens barrel 305 are different from those in the first and second embodiments.

  In the lens barrel 305 of the lens unit according to Embodiment 3, three through holes 356 are formed at equal intervals in the circumferential direction in the vicinity of the rear side end portion of the outer peripheral surface. The through hole 356 is formed through the lens holding part 51 in the radial direction of the lens barrel 305. That is, the through hole 356 is formed so as to communicate with the peripheral surface 14 of the first infrared lens 1 held by the lens holding portion 51.

  Further, in the lens barrel 305, three through holes 355 are formed at equal intervals in the circumferential direction in the vicinity of the front end portion of the outer peripheral surface. The through-hole 355 is formed in a portion of the lens barrel 305 that is screwed into the lens holder 6 and provided with a thread groove, and is inserted into the lens barrel 305 in the radial direction of the lens barrel 305. It is formed so as to communicate with the peripheral surface 24 of the lens 2.

  As described above, the through-holes 355 and 356 of the lens barrel 305 are communicated with the peripheral surface 14 of the first infrared lens 1 and the peripheral surface 24 of the second infrared lens 2, and the peripheral surface 14 and the first infrared lens 1 of the first infrared lens 1. 2 By forming on the inner peripheral surface of the lens barrel 305 in contact with the peripheral surface 24 of the infrared lens 2, a photocurable adhesive is poured from the through holes 355 and 356, and infrared rays are irradiated from the outside of the lens barrel 5 to pierce the through holes. The photocurable adhesive in 355 and 356 can be cured. Therefore, the first infrared lens 1 and the second infrared lens 2 can be bonded and fixed to the lens barrel 305 using a photocurable adhesive.

  Similarly to the lens unit according to the first embodiment, the lens unit according to the third embodiment having the above configuration uses a photocurable adhesive without using a thermosetting adhesive that requires heating, and uses a photocurable adhesive. The first infrared lens 1 and the second infrared lens 2 can be quickly fixed to each other. Since the first infrared lens 1 and the second infrared lens 2 can be fixed with high precision, the optical performance and reliability of the lens unit can be improved.

  In addition, since the other structure of the lens unit which concerns on Embodiment 3 is the same as that of the lens unit which concerns on Embodiment 1, it attaches | subjects the same code | symbol to the same location, and abbreviate | omits detailed description.

(Embodiment 4)
FIG. 7 is an exploded perspective view showing the configuration of the lens unit according to Embodiment 4 of the present invention, and FIG. 8 is a cross-sectional view showing the configuration of the lens unit. Although the lens units according to the above-described first to third embodiments are configured to include two infrared lenses, the lens unit according to the fourth embodiment is configured to include three infrared lenses.

  The lens unit according to Embodiment 4 includes first to third infrared lenses 401 to 403, a lens barrel 405, a lens holder 6, a first spacer 407, and a second spacer 409. In the lens unit, the first infrared lens 401, the first spacer 407, the second infrared lens 402, the second spacer 409, and the third infrared lens 403 are sequentially inserted into the lens barrel 405, and the lens is pressed on the front side of the lens barrel 405. 6 is fixed.

  The first infrared lens 401 has a disk shape, and has a convex surface 411 on the front side and a concave surface 412 on the back side. The first infrared lens 401 has a flange portion 413 in which peripheral portions of the front and back surfaces are formed smoothly. The flange portion 413 is a portion for holding the first infrared lens 401 in the lens barrel 405. Similarly, the second infrared lens 402 is a lens having a concave surface 421 on the front side and a convex surface 422 on the back side, and has a flange 423 in which peripheral portions of the front and back surfaces are formed smoothly. The third infrared lens 403 is a lens having a convex surface 431 on the front side and a concave surface 432 on the back side, and the peripheral portion of the back surface is formed smoothly. The second infrared lens 402 and the third infrared lens 403 have substantially the same diameter and are larger in diameter than the first infrared lens 401.

  The lens barrel 405 has a cylindrical shape, and a lens holding portion 451 for holding the first infrared lens 401 is formed on the back side. The lens holding portion 451 is a stepped portion that protrudes from the end on the back side of the lens barrel 405 over the entire circumference of the inner peripheral surface and has a stepped shape in which the inner diameter from the front side to the back side decreases stepwise. The lens holding portion 451 has a portion in contact with the peripheral surface 414 of the first infrared lens 401 and a portion in contact with the back surface of the collar portion 413 of the first infrared lens 401. The first infrared lens 401 is attached from the front side. The first infrared lens 401 is fitted and held in the lens holding portion 451 by inserting the lens barrel 405 into contact with the lens holding portion 451 with the back surface of the peripheral surface 414 and the collar portion 513.

  A through-hole 457 is formed in the radial direction of the lens barrel 405 in the vicinity of the rear side end portion of the outer peripheral surface of the lens barrel 405 so as to communicate the inside and outside of the lens holding portion 451 of the lens barrel 405. That is, the through hole 457 is formed so as to communicate with the peripheral surface 414 of the first infrared lens 401 held by the lens holding portion 451. Three through holes 457 are formed at equal intervals in the circumferential direction of the lens barrel 405.

  The first spacer 407 has a cylindrical shape and has an outer diameter that is substantially the same as the inner diameter of the lens barrel 405, and the first spacer 407 can be inserted into the lens barrel 405 from the front side and fitted. Further, the inside of the first spacer 407 is formed in a tapered shape in which the inner diameter gradually decreases from the front side to the back side. In the lens barrel 405, the end surface on the back side of the first spacer 407 contacts the front surface of the flange portion 413 of the first infrared lens 401, and the end surface on the front side of the first spacer 407 is the flange portion 423 of the second infrared lens 402. It touches the back of the. That is, the first spacer 407 is interposed between the first infrared lens 401 and the second infrared lens 402, and thereby the first infrared lens 401 and the second infrared lens 402 are positioned.

  The inner diameter of the lens barrel 405 is formed to be equal to or slightly larger than the inner diameter of the second infrared lens 402 and the third infrared lens 403, and after the first infrared lens 401 and the first spacer 407 are inserted into the lens barrel 405. Then, the second infrared lens 402 can be inserted into the lens barrel 405, and the second infrared lens 402 can be fitted to the approximate center position of the lens barrel 405 in the axial direction.

  A through-hole 456 is formed in the radial direction of the barrel 405 so as to communicate the inside and outside of the barrel 405 at the approximate center in the axial direction of the outer peripheral surface of the barrel 405. That is, the through hole 456 is formed so as to communicate with the peripheral surface 424 of the second infrared lens 402 that is inserted into the lens barrel 405 and positioned by the first spacer 407. Three through holes 456 are formed at equal intervals in the circumferential direction of the lens barrel 405.

  The second spacer 409 has a cylindrical shape and has an outer diameter that is substantially the same as the inner diameter of the lens barrel 405. The second spacer 409 can be inserted into the lens barrel 405 from the front side and fitted. In the lens barrel 405, the end surface on the back side of the second spacer 409 contacts the front surface of the flange 423 of the second infrared lens 402, and the end surface on the front side of the second spacer 409 is smooth on the back surface of the third infrared lens 403. Abut against the part. That is, the second spacer 409 is interposed between the second infrared lens 402 and the third infrared lens 403, and thereby the positioning of the second infrared lens 402 and the third infrared lens 403 is performed.

  The third infrared lens 403 can be inserted into the lens barrel 405. When the third infrared lens 403 is in contact with the second spacer 409 inserted into the lens barrel 405, the third infrared lens 403 is inserted. The lengths of the second spacer 409 and the lens barrel 405 are adjusted so that a part of the peripheral surface 434 is exposed from the lens barrel 405. Thus, after the third infrared lens 403 is inserted into the lens barrel 405, the peripheral surface 434 exposed from the lens barrel 405 can be gripped with a jig or the like, and the third infrared lens 403 can be aligned.

  Further, a through hole 455 is formed in the radial direction of the lens barrel 405 so as to communicate the inside and outside of the lens barrel 405 in the vicinity of the front end portion of the outer peripheral surface of the lens barrel 405. That is, the through-hole 455 is formed so as to communicate with the peripheral surface 434 of the third infrared lens 403 that is inserted into the lens barrel 405 and positioned by the second spacer 409. Three through holes 455 are formed at equal intervals in the circumferential direction of the lens barrel 405.

  A thread groove is formed in the vicinity of the front side end portion of the outer peripheral surface of the lens barrel 405. By screwing into a thread groove formed on the inner peripheral surface of the lens retainer 6, the lens barrel 405 and the lens retainer 6 are fixed. Fixing can be performed. By screwing the lens holder 6 into the lens barrel 405, the third infrared lens 403 is firmly fixed by being sandwiched between the lens holder 6 and the second spacer 409 in the axial direction. Further, the through hole 455 is formed in a portion of the lens barrel 405 where the thread groove is provided, and is covered and covered by screwing and fixing the lens presser 6 to the lens barrel 405.

  When assembling the lens unit according to the fourth embodiment, first, the first infrared lens 401 is inserted into the lens barrel 405 and is fitted and held in the lens holding portion 451, and then is light-cured and bonded in the through hole 457. The agent is poured, and the photocurable adhesive in the through-hole 457 is irradiated with ultraviolet rays from the outside of the lens barrel 405 to be cured. Next, the first spacer 407 is inserted and fitted into the lens barrel 405, and the second infrared lens 402 is inserted and fitted into the lens barrel 405 until the rear surface abuts against the first spacer 407, and then penetrates. A photocurable adhesive is poured into the hole 456, and the photocurable adhesive in the through hole 456 is irradiated with ultraviolet rays from the outside of the lens barrel 405 to be cured.

  Next, the second spacer 409 is inserted and fitted into the lens barrel 405, and the third infrared lens 403 is inserted and fitted into the lens barrel 405 until the back surface abuts against the second spacer 409. The lens 403 is aligned. After the alignment work is completed, a photocurable adhesive is poured into the through hole 455, and the photocurable adhesive in the through hole 455 is irradiated from the outside of the lens barrel 405 to be cured. Thereafter, the lens holder 6 and the lens barrel 405 are screwed together to complete the assembly of the lens unit. After the first infrared lens 401, the first spacer 407, the second infrared lens 402, the second spacer 409, and the third infrared lens 403 are inserted into the lens barrel 405, the photo-curing adhesive is attached to the through holes 455 to 457. It may be a procedure in which an agent is poured and cured.

  Even if the lens unit according to the fourth embodiment having the above-described configuration includes three or more infrared lenses in the lens barrel 405, the lens barrel 405 is similar to the lens unit according to the first to third embodiments. By forming the through holes 455 to 457, the first infrared lens 401 to the third infrared lens 403 and the lens barrel 405 can be bonded and fixed with a photocurable adhesive. Therefore, the first infrared lens 401 to the third infrared lens 403 can be quickly fixed, and there is no possibility that the first infrared lens 401 to the third infrared lens 401 are displaced or decentered. Optical performance and reliability can be improved.

  In addition, since the other structure of the lens unit which concerns on Embodiment 4 is the same as that of the lens unit which concerns on Embodiment 1, the same code | symbol is attached | subjected to the same location and detailed description is abbreviate | omitted.

It is a perspective view which shows the structure of the lens unit which concerns on Embodiment 1 of this invention. It is a disassembled perspective view which shows the structure of the lens unit which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the structure of the lens unit which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the structure of the lens unit which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the structure of the lens unit which concerns on the modification of Embodiment 2 of this invention. It is sectional drawing which shows the structure of the lens unit which concerns on Embodiment 3 of this invention. It is a disassembled perspective view which shows the structure of the lens unit which concerns on Embodiment 4 of this invention. It is sectional drawing which shows the structure of the lens unit which concerns on Embodiment 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st infrared lens 2 2nd infrared lens 5 Lens barrel 6 Lens holder 7 Spacer 14 Peripheral surface 24 Peripheral surface 51 Lens holding part 55, 56 Through-hole 71 Recessed part 205, 205a Lens barrel 206 Lens holder 209 Cover member 261 Tube part ( Cover member)
305 Lens barrel 307 Spacer 355, 256 Through hole 401 First infrared lens 402 Second infrared lens 403 Third infrared lens 405 Lens barrel 407 First spacer 409 Second spacer 414, 424, 434 Peripheral surface 455, 456, 457 Through hole

Claims (5)

In a lens unit comprising a plurality of infrared lenses, a lens barrel in which the infrared lenses are inserted, and a cylindrical spacer interposed between the plurality of infrared lenses and fitted in the lens barrel,
The peripheral surface of the lens barrel is formed with a through-hole leading to the peripheral surface of the infrared lens inserted into the lens barrel and / or a portion of the spacer that contacts the infrared lens. Characteristic lens unit. In the spacer, a concave portion is formed in a portion where the infrared lens contacts,
The lens unit according to claim 1, wherein the through hole is formed so as to communicate with the concave portion. The lens unit according to claim 1, further comprising a cover member that covers the through hole. A lens holder that is fixed to the lens barrel, abuts on a peripheral portion of the infrared lens disposed on the outermost side in the axial direction of the lens barrel, and holds the infrared lens;
The lens unit according to claim 3, wherein the cover member is provided integrally with the lens presser. The lens unit according to any one of claims 1 to 4, wherein a plurality of the through holes are formed at equal intervals in a circumferential direction of the lens barrel.

Images