Lens unit and camera unit

Abstract

To provide a lens unit that can prevent the occurrence of dew condensation on a lens, while easily improving assemblability.SOLUTION: A lens unit has: a first lens arranged on the most object side; a second lens arranged closer to an image side than the first lens; a lens barrel supporting the first lens and the second lens; a first sealing part sealing between the first lens and the lens barrel; a lens barrel holder supporting the lens barrel; and an adhesive bonding the lens barrel holder and the lens barrel to each other. The second lens is supported without a gap on the whole circumference. The lens barrel is provided with a communication hole communicating the inside and outside of the lens barrel. The communication hole is blocked by the adhesive facing the lens barrel holder.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a lens unit and a camera unit. [Background technology]

[0002] Conventionally, there has been known a lens unit in which an O-ring is compressed and held between the outer diameter portion of a first lens positioned closest to the object and the inner circumferential surface of a lens barrel to ensure waterproof performance. Patent Document 1 discloses a lens unit that can perform an O-ring leak test using a hole provided in the lens barrel that connects the space between the first lens and a second lens positioned on the image side of the first lens with the space outside the lens barrel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-144307 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the lens unit of Patent Document 1 requires an additional process for sealing the hole in the lens barrel in addition to the usual processes, which increases the number of facilities and parts. If the hole is not sealed, there is a risk of condensation forming on the image side of the first lens due to changes in the ambient temperature during use. If the hole is removed, there is no escape route for the air in the space between the first and second lens elements, and the repulsion of the air makes it impossible to insert the first lens, with the O-ring attached, into the lens barrel.

[0005] An object of the present invention is to provide a lens unit that can be easily assembled and can suppress the occurrence of condensation on the lens. [Means for solving the problem]

[0006] A lens unit according to one aspect of the present invention includes a first lens arranged closest to the object, a second lens arranged closer to the image than the first lens, a lens barrel supporting the first lens and the second lens, and a second lens sealing the gap between the first lens and the lens barrel. One envelope a lens barrel holder for supporting the lens barrel; and an adhesive for bonding the lens barrel holder to the lens barrel. All around teeth, It abuts against the lens barrel in a direction perpendicular to the optical axis. The lens barrel is provided with a communication hole that connects the inside and outside of the lens barrel, and the communication hole is Through adhesive Opposite to the lens barrel holder death It is characterized by the fact that [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a lens unit that can easily improve assembly efficiency and can suppress the occurrence of condensation on the lens. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a lens unit according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the camera unit of the first embodiment. [Figure 3] FIG. 10 is a cross-sectional view of a camera unit according to a second embodiment. [Figure 4] FIG. 10 is a perspective view illustrating a fixing portion of the second embodiment. [Figure 5] FIG. 10 is a cross-sectional view of a lens unit according to a third embodiment. [Figure 6] FIG. 10 is a perspective view showing a support portion for a medium lens in Example 3. [Figure 7] FIG. 10 is a perspective view showing a state in which a medium lens of Example 3 is supported. [Figure 8] FIG. 10 is a cross-sectional view of a camera unit according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same components, and redundant explanations will be omitted. [Example]

[0010] FIG. 1 is a cross-sectional view of lens unit 100 taken along a plane passing through the optical axis of lens unit 100 and a ventilation hole (vent hole, communication hole) 24 (described later). Lens unit 100 includes lens group 1, lens barrel 2, and lens barrel holder 203 (described later). In this embodiment, lens group 1 includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, and a fifth lens 15, arranged in this order from the object side to the image side, and is held inside lens barrel 2. Lens barrel 2 is a roughly cylindrical member with openings at both ends. Specifically, lens barrel 2 has an object-side opening 21 and an image-side opening 22. Note that, although the number of lenses included in lens group 1 is five in this embodiment, the present invention is not limited to this. Lens group 1 may include a first lens arranged closest to the object side and a second lens arranged on the image side of the first lens.

[0011] The first lens 11 to the fifth lens 15 are held inside a hole provided in the lens barrel 2 that connects the object-side opening 21 and the image-side opening 22. A sealant (first sealing portion) 3 is provided between the inner peripheral surface of the lens barrel 2 and the outer peripheral surface of the first lens 11 to prevent water, dust, and the like from entering the inside of the lens barrel 2. The sealant 3 is, for example, a resin such as an adhesive, and is more preferably an O-ring made of elastically deformable rubber. If the sealant 3 is a rubber O-ring, it is desirable that the sealant 3 be compressed and held between the inner peripheral surface of the lens barrel 2 and the outer peripheral surface of the first lens 11.

[0012] The second lens 12 is fixed in place by a fixing portion 25 formed by deforming a portion of the lens barrel 2, while being abutted against the third lens 13 in the optical axis direction. The fixing portion 25 abuts against the second lens 12 without any gaps around the entire circumference. This makes it possible to prevent air from passing through a gap between the second lens 12 and the inner surface of the lens barrel 2.

[0013] Here, we will explain "thermal crimping," a typical method for deforming a portion of the lens barrel 2 to form a fixing portion 25 that supports the second lens 12 without gaps around its entire circumference. The fixing portion 25 in FIG. 1 is formed by a thermal crimping process. Before the thermal crimping process, the portion of the lens barrel 2 corresponding to the fixing portion 25 has a shape similar to crimping claws 2b. In the thermal crimping process, the second lens 12 is first inserted into the inner periphery of the lens barrel 2, thereby fitting the second lens 12 to the lens barrel 2 in the diametric direction. Next, a forming jig (not shown), which has been heated to near the melting point of the lens barrel 2, is brought into contact with the portion corresponding to the fixing portion 25 and pressed in the direction of insertion of the second lens 12, thereby forming the fixing portion 25. The forming jig is then cooled to a predetermined temperature and then separated from the fixing portion 25, completing the thermal crimping process. As described above, by pressing fixed portion 25, which is a part of lens barrel 2 that has been temporarily liquefied, against second lens 12, second lens 12 is supported by fixed portion 25 without any gaps around the entire periphery.

[0014] It should be noted that it is not necessarily the second lens 12 that is supported without gaps around its entire circumference by fixing portion 25, but rather any of the second lens 12 to the fifth lens 15. Furthermore, fixing of each lens around its entire circumference does not necessarily have to be achieved by deforming lens barrel 2, and the lenses may be fixed without gaps to lens barrel 2 with, for example, an adhesive.

[0015] Furthermore, the lens barrel 2 is provided with an air vent 24 that connects a space 23 (inside the lens barrel 2) between the first lens 11 and the second lens 12 with the outside of the lens barrel 2. By providing the air vent 24, it becomes possible to exhaust air from the space 23 to the outside when assembling the first lens 11 and the sealing material 3 to the lens barrel 2, improving ease of assembly.

[0016] When first lens 11 is fixed to lens barrel 2, a part of lens barrel 2 may be deformed, an adhesive may be used, or a pressing ring may be used.

[0017] 2(a) is a cross-sectional view of camera unit 200 taken along a plane passing through the optical axis of lens unit 100 and air vent 24. Camera unit 200 has lens unit 100, image sensor 201, sensor board 202, lens barrel holder 203, and adhesive 204. Image sensor 201 and sensor board 202 are disposed inside lens barrel holder 203. Image sensor 201 is mounted on sensor board 202 and converts light incident through lens unit 100 into an electrical signal. The electrical signal converted by image sensor 201 undergoes predetermined signal processing by an electrical circuit (not shown) and is then output from camera unit 200 to the outside.

[0018] The lens unit 100 functions as a camera unit 200 when integrated with a barrel holder 203 to which an image sensor 201 and a sensor substrate 202 are attached. After the lens unit 100 and the image sensor 201 are adjusted to an optimal relative positional relationship using a predetermined device, the lens unit 100 and the barrel holder 203 are bonded together with adhesive 204. Before hardening, the adhesive 204 has a viscosity that prevents a gap from forming between the adhesive surfaces of the lens unit 100 and the barrel holder 203, even when the relative positions of the two are adjusted. The clearance in the optical axis direction between the adhesive portion 203a of the barrel holder 203 and the barrel 2 (i.e., the thickness of the adhesive 204) is approximately 1 mm. This allows the relative positions of the lens unit 100 and the image sensor 201 to be adjusted along six axes. After the relative positions of the lens unit 100 and the image sensor 201 are adjusted, the adhesive 204 is hardened to bond the lens unit 100 and the barrel holder 203 together. This allows the adhesive 204 to hold the lens barrel holder 203 and the lens barrel 2. At this time, the air vent 24 is blocked by the hardened adhesive 204 that faces the lens barrel holder 203. In other words, the air vent 24 and the adhesive portion 203a overlap when viewed in the optical axis direction.

[0019] The adhesive 204 may be any material that can hold the lens barrel holder 203 and the lens barrel 2 and that can adjust the relative position of the lens unit 100 and the imaging sensor 201 in six axes, and may be, for example, a double-sided adhesive sheet.

[0020] In this embodiment, the extension direction of the ventilation holes 24 is parallel to the optical axis direction, but the present invention is not limited to this. It is preferable to impose some limitations on the diameter of the ventilation holes 24 in consideration of actual production. For example, if the lens barrel 2 is made of metal, the ventilation holes 24 may be formed by cutting. However, if the diameter of the ventilation holes 24 is too small, the strength of the drill bit will be insufficient, resulting in frequent replacement of the bit. Furthermore, if the lens barrel 2 is made of resin, if the diameter of the ventilation holes 24 is too small, the strength of the mold used for resin molding will be insufficient, resulting in a shorter mold maintenance cycle. However, to ensure that the ventilation holes 24 are reliably sealed with the cured adhesive 204, it is preferable to reduce the diameter of the ventilation holes 24. Thus, considering various factors involved in actual production, it is preferable that the diameter of the ventilation holes 24 be approximately 1 to 3 mm.

[0021] The effect of sealing the ventilation hole 24 with adhesive 204 will be described below. When the camera unit 200 captures an image, electronic components such as the imaging sensor 201 mounted on the sensor board 202 generate heat due to electrical current. This heat causes moisture held by various components of the camera unit 200 to evaporate inside the camera unit 200, filling the space 26 within the camera unit 200 with hot, humid air. In addition to the evaporation of moisture held by the components within the camera unit 200, the air in the space 26 may become humid due to the intrusion of water vapor from the outside into the camera unit 200. When the ventilation hole 24 is sealed with adhesive 204, humid air will not infiltrate the space 23 through the ventilation hole 24. Furthermore, because the second lens 12 is tightly fixed to the lens barrel 2 by the fixing portion 25, humid air will not infiltrate the space 23 through gaps between each lens and the inner circumferential surface of the lens barrel 2. Therefore, even if the temperature of the first lens 11 becomes lower than the temperature of the space 23 due to the outside air temperature, the air in the space 23 is not hot and humid, so condensation on the image-side surface of the first lens 11 is suppressed.

[0022] Hot and humid air can enter the space between the second lens 12 and the third lens 13 through the gap between the third lens 13 and the inner circumferential surface of the lens barrel 2. However, the insulating effect of the space 23 prevents the temperature of the second lens 12 from becoming lower than the temperature of the space between the second lens 12 and the third lens 13 due to the outside air temperature. This prevents condensation from forming on the image-side surface of the second lens 12. For the same reasons as the second lens 12, condensation is also prevented from forming on the lens surfaces of the third lens 13 to the fifth lens 15.

[0023] In this embodiment, the case where the second lens 12 is tightly fixed to the lens barrel 2 by the fixing portion 25 has been described, but the same effect can be obtained if any of the second lens 12 to the fifth lens 15 is tightly fixed to the lens barrel 2.

[0024] As explained above, considering the ease of assembly and the function of suppressing condensation, providing one ventilation hole 24 in the lens barrel 2 is sufficient, but multiple ventilation holes 24 may also be provided in the lens barrel 2. In this case, it is preferable that the multiple ventilation holes 24 be arranged at equal intervals around the optical axis (arranged at equal intervals around the circumference of the lens barrel 2). Furthermore, as shown in FIG. 2(b), multiple holes may be provided in the lens barrel 2, with at least one of the multiple holes being a ventilation hole 24 that connects the inside and outside of the space 23, and the remaining holes being blind holes 27 that do not connect the inside and outside of the space 23. In this embodiment, one ventilation hole 24 and three blind holes 27 are arranged at equal intervals around the optical axis in the lens barrel 2.

[0025] Here, we will explain the effect of providing multiple holes, including the air vent 24, in the lens barrel 2, at equal intervals around the optical axis. Any misalignment after adjusting the relative position between the lens unit 100 and the image sensor 201 directly leads to a decrease in the imaging performance of the camera unit 200, so it is desirable to minimize this misalignment. However, the adhesive 204 may shrink as it hardens. The hardening and shrinkage of the adhesive 204 has the tendency to cause misalignment of the relative positions between the lens unit 100 and the image sensor 201. If a single air vent 24 is provided on the bonding surface 2a of the lens barrel 2, the hardening and shrinkage of the doughnut-shaped adhesive 204 may become unbalanced, potentially causing misalignment of the relative positions between the lens unit 100 and the image sensor 201. On the other hand, providing multiple holes at equal intervals around the optical axis is expected to have the effect of making the hardening and shrinkage of the adhesive 204 uniform. Furthermore, by making one or more of the holes provided in the lens barrel 2 blind holes 27, that is, by reducing the number of through holes that need to be blocked with adhesive 204, the yield can be improved.

[0026] As described above, the lens unit 100 can be positioned to protrude from the exterior components of a vehicle because it can suppress condensation on each lens. For example, when an imaging device using the camera unit 200 is mounted on a vehicle, the imaging device can be embedded inside a decorative cover of the vehicle, leaving only the tip of the lens unit 100 exposed, making the lens unit 100 less noticeable. This allows for an imaging device that does not interfere with the vehicle's design. Furthermore, because high-temperature, high-humidity air generated by the camera unit 200 due to heat generated by the imaging sensor 201 cannot enter the space 23, condensation on the image-side surface of the first lens 11 can be suppressed even when the temperature of the first lens 11 drops due to the outside temperature. Furthermore, the insulating effect of the space 23 can suppress a temperature drop in the second lens 12, thereby suppressing condensation on the image-side surface of the second lens 12. [Example]

[0027] FIG. 3 is a cross-sectional view of camera unit 200 taken along a plane passing through the optical axis of lens unit 100 and vent hole 24. An elastically deformable sealant (second sealing portion) 4 is compressed and held between the inner circumferential surface of lens barrel 2 and the outer circumferential surface of second lens 12. Sealant 4 prevents humid air generated by heat from imaging sensor 201 from entering space 23 through a gap between second lens 12 and the inner circumferential surface of lens barrel 2. Therefore, fixing portion 25 does not need to fix second lens 12 to lens barrel 2 along the entire circumference. For example, as shown in FIG. 4, fixing portion 25 may fix second lens 12 at multiple locations around the circumference, or may fix second lens 12 over most of the circumference but leave some portions unfixed due to local cutouts.

[0028] By fixing the second lens 12 using the above configuration of this embodiment, it is possible to prevent humid air from entering the space 23 through the gaps between the second lens 12 to the fifth lens 15 and the inner circumferential surface of the lens barrel 2, as in the first embodiment. Therefore, even if the temperature of the first lens 11 becomes lower than the temperature of the space 23 due to the outside air temperature, the air in the space 23 is not high in temperature and humidity, so condensation on the image-side surface of the first lens 11 can be prevented. Furthermore, due to the insulating effect of the space 23, it is possible to prevent the temperature of the second lens 12 from becoming lower than the temperature of the space between the second lens 12 and the third lens 13 due to the outside air temperature. This prevents condensation on the image-side surface of the second lens 12. For the same reasons as for the second lens 12, it is also possible to prevent condensation on the surfaces of the third lens 13 to the fifth lens 15.

[0029] Furthermore, when the second lens 12 is fixed as in this embodiment, there is no limitation on the method for fixing the third lens 13 to the fifth lens 15. [Example]

[0030] 5(a) is a cross-sectional view of the lens unit 100 when cut along a plane passing through the optical axis of the lens unit 100. The basic configuration of the lens unit 100 of this embodiment is similar to that of the lens unit 100 of embodiment 1. In this embodiment, configurations that differ from embodiment 1 will be described, and descriptions of configurations that are similar to those of embodiment 1 will be omitted.

[0031] Lens unit 100 has a lens group 1, a lens barrel 2, and a lens barrel holder 203. In this embodiment, lens group 1 is made up of a first lens (front lens) 11, a second lens 12, a third lens 13, a fourth lens 14, and a fifth lens (rear lens) 15, arranged in that order from the object side to the image side, and is held inside lens barrel 2. Note that second lens 12, third lens 13, and fourth lens 14, which are arranged in positions sandwiched between the front lens and the rear lens, are collectively referred to as middle lenses.

[0032] The first lens 11 and the fifth lens 15 are fixed by fixing portions 24a and 24c that are formed by deforming a portion of the lens unit 100 while the first lens 11 and the fifth lens 15 are abutted against the lens barrel 2 in the optical axis direction. The fixing portions 24a and 24c abut against the first lens 11 and the fifth lens 15 without any gaps around their entire circumference. This makes it possible to prevent air from passing through gaps in the lens barrel 2.

[0033] Here, we will explain "thermal crimping," a typical method for deforming a portion of the lens barrel 2 to form a fixed portion 24a that supports the first lens 11 without gaps around its entire circumference. The fixed portion 24a in FIG. 5(a) is formed by a thermal crimping process. Before the thermal crimping process, the portion of the lens barrel 2 corresponding to the fixed portion 24a has a shape resembling a crimping claw 24d. In the thermal crimping process, the first lens 11 is first inserted into the inner periphery of the lens barrel 2, thereby fitting the first lens 11 to the lens barrel 2 in the diametric direction. Next, a forming jig (not shown), which has been heated to near the melting point of the lens barrel 2, is brought into contact with the portion corresponding to the fixed portion 24a and pressed in the insertion direction of the first lens 11, thereby forming the fixed portion 24a. The forming jig is then cooled to a predetermined temperature and then separated from the fixed portion 24a, completing the thermal crimping process. As described above, by pressing fixed portion 24a, which is a part of lens barrel 2 that has been temporarily liquefied, against first lens 11, first lens 11 is supported without gaps all around by fixed portion 24a. Note that fixed portion 24c, which supports fifth lens 15 without gaps all around, is also formed in a similar manner.

[0034] Note that the first lens 11 and the fifth lens 15 do not necessarily have to be fixed around their entire circumference by deforming the lens barrel 2, and may be fixed to the lens barrel 2 without any gaps, for example, by an adhesive. As shown in FIG. 5(b), a sealant 4 may be compressed and held between the fifth lens 15 and the lens barrel 2.

[0035] Of the middle lenses that are fixed by deforming the lens barrel 2, the lens that is positioned closest to the object side is fixed with a gap that connects the object side and image side of the lens barrel 2. In Figure 5(a), the second lens 12 and the third lens 13 are fixed in the above state.

[0036] First, when the third lens 13 is inserted into the lens barrel 2, radial support portion (first lens support portion) 29b partially supports the third lens 13 in the radial direction perpendicular to the optical axis direction. In this case, as shown in FIG. 6, multiple radial support portions 29b may be provided. In FIG. 6, three radial support portions 29b are provided. The three radial support portions 29b are arranged at equal intervals around the optical axis. In the optical axis direction, thrust support portion (second lens support portion) 29a partially supports the third lens 13. In this case, as shown in FIG. 6, multiple thrust support portions 29a may be provided. In FIG. 6, three thrust support portions 29a are provided. The three thrust support portions 29a are arranged at equal intervals around the center. In other words, the radial gap 28a and the thrust gap 28b are provided between the third lens 13 and the lens barrel 2, so that a gap communicating between the space on the object side of the third lens 13 and the space on the image side is formed.

[0037] Next, the second lens 12 is inserted into the lens barrel 2 and pushed in until the image-side surface of the second lens 12 abuts against the object-side surface of the third lens 13. This determines the thrust direction position of the second lens 12. In the radial direction, the radial support portion 29b supports the second lens 12 in the same way as the third lens 13.

[0038] By forming fixing portion 24b by thermal caulking in the above-described state, second lens 12 and third lens 13 are fixed to lens barrel 2. Fixing portion 24b is not formed around the entire circumference as shown in Fig. 7, but is formed partially along the circumferential direction. This maintains a state in which space 23a on the object side of second lens 12, space 23b between second lens 12 and third lens 13, and space 23c on the image side of third lens 13 are in communication.

[0039] When the sealant 3 and first lens 11 are inserted into the lens barrel 2 in the above state, the air in space 23a is compressed as the first lens 11 advances until its image-side surface abuts the lens barrel 2. However, because the second lens 12 and the third lens 13 are fixed with a gap between them and the lens barrel 2, the air in spaces 23b and 23c is also compressed at the same time. Although no particular mention was made of the method for fixing the fourth lens 14, by fixing the fourth lens 14 to the lens barrel 2 in the same way as the third lens 13, the air compressed by the insertion of the first lens 11 and the sealant 3 extends to space 23d. By fixing each middle lens with a gap between them and the lens barrel 2 in this way, it is possible to reduce the compression ratio of the air inside the lens barrel 2 that is compressed by the insertion of the first lens 11 and the sealant 3. This improves the ease of assembly of the lens unit 100.

[0040] In this embodiment, three fixing portions 24b are arranged at equal intervals around the optical axis, but the present invention is not limited to this. For example, only one fixing portion 24b may be provided around the entire circumference, or four or more fixing portions 24b may be provided, and the fixing portions 24b may not be arranged at equal intervals around the optical axis.

[0041] Furthermore, as long as the center lens can be fixed with a gap between the object side and the image side, the fixing method is not limited to thermal caulking. For example, adhesive, a press ring, or a C-ring may be used.

[0042] The effect of fixing fifth lens 15 to lens barrel 2 without any gaps will be described below. Figure 8 is a cross-sectional view of camera unit 200 taken along a plane passing through the optical axis of lens unit 100. Lens unit 100 functions as camera unit 200 when integrated with lens barrel holder 203 to which image sensor 201 and sensor board 202 are attached. At this time, lens unit 100 and image sensor 201 are adjusted by a specified device to have an optimal relative positional relationship, and then lens unit 100 and lens barrel holder 203 are bonded together with adhesive 204.

[0043] When the camera unit 200 captures an image, electronic components such as the image sensor 201 mounted on the sensor board 202 generate heat due to the passage of electricity. This heat causes moisture held by the various components of the camera unit 200 to evaporate inside the camera unit 200, filling the space 26 within the camera unit 200 with hot, humid air. In addition to the evaporation of moisture held by the components within the camera unit 200, water vapor may also enter the camera unit 200 from the outside, causing the air in the space 26 to become humid.

[0044] When fifth lens 15 is fixed to lens barrel 2 without any gaps around its entire circumference, humid air will not pass between fifth lens 15 and lens barrel 2 and enter space 23. Therefore, even if the temperature of first lens 11 becomes lower than the temperature of space 23 due to the outside air temperature, the air in space 23 is not hot and humid, so condensation on the image-side surface of first lens 11 is suppressed.

[0045] In spaces 23a to 23d, air can move to some extent in the gaps between each middle lens and the inner circumferential surface of lens barrel 2, but these gaps are extremely small. Therefore, the insulating effect of space 23a prevents second lens 12 from becoming colder than the temperature in space 23b due to the outside air temperature. This prevents condensation from forming on the image-side surface of second lens 12. For the same reason as second lens 12, condensation is also prevented from forming on the lens surfaces of third lens 13 to fifth lens 15.

[0046] As described above, the lens unit 100 can be positioned to protrude from the exterior components of a vehicle because it can suppress condensation on each lens. For example, when an imaging device using the camera unit 200 is mounted on a vehicle, the imaging device can be embedded inside a decorative cover of the vehicle, leaving only the tip of the lens unit 100 exposed, making the lens unit 100 less noticeable. This allows for an imaging device that does not interfere with the vehicle's design. Furthermore, because high-temperature, high-humidity air generated by the camera unit 200 due to heat generated by the imaging sensor 201 cannot enter the space 23, condensation on the image-side surface of the first lens 11 can be suppressed even when the temperature of the first lens 11 drops due to the outside temperature. Furthermore, the insulating effect of the space 23 can suppress a temperature drop in the second lens 12, thereby suppressing condensation on the image-side surface of the second lens 12.

[0047] The disclosure of this embodiment includes the following configurations and methods.

[0048] (Configuration 1) a first lens arranged closest to the object; a second lens arranged closer to the image than the first lens; a lens barrel supporting the first lens and the second lens; a first sealing portion that seals the gap between the first lens and the lens barrel; a lens barrel holder for supporting the lens barrel; an adhesive that bonds the lens barrel holder and the lens barrel; the second lens is supported without gaps around its entire periphery, the lens barrel is provided with a communication hole that connects the inside and outside of the lens barrel; The lens unit is characterized in that the communication hole is closed by the adhesive facing the lens barrel holder. (Configuration 2) The lens unit according to configuration 1, wherein the second lens is fixed by deformation of a part of the lens barrel over the entire circumference. (Configuration 3) The lens unit according to configuration 1, wherein the second lens is adhered to the lens barrel over the entire periphery with an adhesive. (Configuration 4) The lens unit according to configuration 1, further comprising an elastically deformable second sealing portion that seals the gap between the second lens and the lens barrel. (Configuration 5) the lens barrel has a plurality of holes including the air vent; The lens unit according to any one of configurations 1 to 4, wherein the plurality of holes are filled with the adhesive and are arranged at equal intervals around the optical axis of the first lens. (Configuration 6) 6. The lens unit according to configuration 5, wherein the plurality of holes include a blind hole that does not communicate between the inside and outside of the lens barrel. (Configuration 7) 7. The lens unit according to claim 5, wherein the plurality of holes include one of the air vents and three blind holes that do not communicate between the inside and outside of the lens barrel. (Configuration 8) The lens unit described in any one of configurations 1 to 7, wherein the lens barrel and the lens barrel holder are bonded with the adhesive while adjusting the positional relationship between the lens unit and an image sensor that is disposed inside the lens barrel holder and converts light incident through the lens unit into an electrical signal. (Configuration 9) The front lens element is located closest to the object. A rear lens element is positioned closest to the image side, and a center lens disposed at a position sandwiched between the front lens and the rear lens; a lens barrel supporting the front lens, the rear lens, and the center lens; a first sealing portion that seals the gap between the front lens and the lens barrel, the front lens and the rear lens are supported by the lens barrel without any gaps around their entire circumference, The lens unit is characterized in that the middle lens is fixed with a gap communicating between the object side and the image side of the lens barrel. (Configuration 10) The lens unit described in configuration 9, wherein the lens barrel includes a first lens support portion that supports the medium lens in a direction perpendicular to the optical axis of the medium lens. (Configuration 11) the first lens support portion is composed of a plurality of first lens support portions, 11. The lens unit according to configuration 10, wherein the plurality of first lens support portions are provided at equal intervals around the optical axis. (Configuration 12) A lens unit described in any one of configurations 9 to 11, characterized in that the lens barrel has a second lens support portion that supports the middle lens in a direction parallel to the optical axis of the middle lens. (Configuration 13) the second lens support portion is composed of a plurality of second lens support portions, 13. The lens unit according to configuration 12, wherein the plurality of second lens support portions are provided at equal intervals around the optical axis. (Configuration 14) A lens unit described in any one of configurations 9 to 13, characterized in that the lens among the middle lenses that is positioned closest to the front lens is fixed by partially deforming the lens barrel in the circumferential direction. (Configuration 15) A lens unit described in any one of configurations 9 to 13, characterized in that the lens among the middle lenses that is located closest to the front lens is partially adhered to the lens barrel in the circumferential direction with an adhesive. (Configuration 16) A lens unit described in any one of configurations 9 to 15, characterized in that the front lens and the rear lens are fixed by deformation of a portion of the lens barrel over the entire circumference. (Configuration 17) The lens unit according to any one of configurations 9 to 15, wherein the front lens and the rear lens are bonded to the lens barrel with an adhesive over their entire circumference. (Configuration 18) 16. The lens unit according to any one of configurations 9 to 15, further comprising an elastically deformable second sealing portion that seals the gap between the rear lens and the lens barrel. (Configuration 19) A lens unit according to any one of configurations 1 to 18; a camera unit having an image sensor that converts light incident through the lens unit into an electrical signal;

[0049] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0050] 2 Telescope tube 3. Sealing material (first sealing part) 11 First lens (first lens) 12 Second lens (second lens) 13 Third lens (second lens) 14 Fourth lens (second lens) 15 5th lens (2nd lens) 24 ventilation holes 100 Lens Unit 203 Telescope holder 204 Adhesive

Claims

1. a first lens arranged closest to the object; a second lens arranged closer to the image than the first lens; a lens barrel supporting the first lens and the second lens; a first sealing portion that seals the gap between the first lens and the lens barrel; a lens barrel holder for supporting the lens barrel; an adhesive that bonds the lens barrel holder and the lens barrel; the second lens is in contact with the lens barrel along a direction perpendicular to the optical axis, the lens barrel is provided with a communication hole that connects the inside and outside of the lens barrel; The lens unit is characterized in that the communication hole faces the lens barrel holder via the adhesive.

2. 2. The lens unit according to claim 1, wherein the entire periphery of the second lens is fixed to the lens barrel by deformation of the lens barrel or by adhesive.

3. 2. The lens unit according to claim 1, further comprising a second sealing portion that seals the gap between the second lens and the lens barrel.

4. The lens unit according to claim 3 , wherein the second sealing portion is elastically deformable.

5. the lens barrel is provided with a plurality of holes including the communication hole, The lens unit according to claim 1 , wherein the plurality of holes are sealed with the adhesive.

6. 6. The lens unit according to claim 5, wherein the plurality of holes include a blind hole that does not communicate between the inside and outside of the lens barrel.

7. A lens unit according to any one of claims 1 to 6; a camera unit having an image sensor that converts light from the lens unit into an electrical signal;

8. 8. The camera unit according to claim 7, wherein the image sensor is disposed inside the lens barrel holder.

Images