Lens unit and camera module

Abstract

To provide a lens unit with a heater, which is advantageous in terms of both the cost and quality.SOLUTION: A lens unit (101A) provided herein has a heater (8) provided in a step-facing area (S1bB) of a second surface (S1b) in a lens barrel (2A) on an eyepiece side of a spacer (S1) provided between a first lens (L1) and a second lens (L2).SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In recent years, in-vehicle cameras have been mounted on automobiles for purposes such as driving assistance, collision prevention, and driving recording. Such in-vehicle cameras include those arranged inside the vehicle cabin and those arranged outside the vehicle cabin. For in-vehicle cameras arranged outside the vehicle cabin, there is an increasing need to mount a heater on the in-vehicle lens for defrosting and fog removal of ice and snow adhering to the lens disposed closest to the object side. For in-vehicle cameras as well, there is a growing demand for versatility to ensure the camera function under all situations (such as weather), and the lens heater is regarded as an effective solution particularly for lens icing in cold regions.

[0003] For example, the lens assembly of Patent Document 1 includes an objective lens having a first surface facing the object side of the lens assembly and a second surface facing the first surface, and further includes a heating assembly having an annular heating element disposed on the second surface of the objective lens.

[0004] Also, the imaging device of Patent Document 2 includes a heater member used for heating a top lens indicating the lens located closest to the subject side among a plurality of lenses included in the lens unit, a region outside the effective region of the top lens, and a reflection suppressing material interposed between the heater member and suppressing light reflection. This reflection suppressing material has a configuration in which a first reflection suppressing material disposed on the top lens side and having irregularities on the surface and a second reflection suppressing material disposed on the heater member side are laminated.

[0005] In addition, in the lens unit of Patent Document 3, the first lens closest to the object side has an object-side lens surface, an image-side lens surface, and an image-side flange surface surrounding the image-side lens surface, and a first housing portion for housing the first lens is configured to include a regulating portion that regulates the position of the first lens in the optical axis direction. The image-side flange surface is provided with a flexible printed circuit board having an inner peripheral region where the flexible printed circuit board is disposed and an outer peripheral region where the regulating portion abuts, and a flexible printed circuit board provided with a heater is disposed on the image-side flange surface of the first lens. In the lens unit of Patent Document 3, a heater is disposed on the image-side flange surface of the first lens, and the first lens and the second lens are caulked and fixed respectively.

[0006] In addition, Patent Document 4 discloses a lens unit in which a heater is disposed between lenses. In this configuration, the lenses are fitted together, and / or an optical element constituting the lens group other than the lens and the lens are fitted together, and / or the optical elements are fitted together to optically position them. Thus, an insertion space for inserting a power supply portion of the heater is secured along the optical axis direction between the lens barrel and the lens and / or the optical element on the radially outer side of the fitting region.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0008] As described above, various technologies have been developed. Furthermore, in order to address the contradictions caused by mounting a heater and to accommodate various structures to be mounted, new forms of lens units equipped with heaters are required.

[0009] One aspect of the present invention aims to realize a lens unit equipped with a heater that is advantageous in terms of cost and quality.

Means for Solving the Problems

[0010] To solve the above problems, a lens unit according to one aspect of the present invention includes a first lens on the most object side, a second lens on the eyepiece side of the first lens, and a spacer between the first lens and the second lens that contacts the first lens on a first surface on the object side and contacts the second lens on a second surface on the eyepiece side. The lens unit further includes a lens barrel that houses at least the first lens, the second lens, and the spacer. The spacer includes a second lens contact region that contacts the second lens on the second surface and a second lens non-contact region that is disposed in the outer diameter direction relative to the second lens contact region and does not contact the second lens. A heater is mounted in the second lens non-contact region of the lens unit.

[0011] To solve the above problems, a camera module according to one aspect of the present invention includes the above-described lens unit and an imaging element.

Advantages of the Invention

[0012] According to one aspect of the present invention, a lens unit equipped with a heater that is advantageous in terms of cost and quality can be provided.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

MODE FOR CARRYING OUT THE INVENTION

[0014] 〔Embodiment 1〕 [Configuration of Lens Unit] Hereinafter, an embodiment of the present invention will be described in detail. FIG. 1 is a cross-sectional view schematically showing the configuration of a lens unit according to Embodiment 1 of the present invention. Note that details of the optical systems of the respective lenses included in the lens unit are omitted from the illustration.

[0015] As shown in FIG. 1, the lens unit 101A has at least lenses L1 to L6, a lens barrel 2A, spacers S1 to S5, a sealing member 4, a retainer 5, a filter 6, and a heater 8. The lens unit 101A is, as an example, an in-vehicle lens unit mounted on an in-vehicle camera.

[0016] <Lens Barrel> The lens barrel 2A has a configuration integrally including a first barrel portion 2a, a stepped portion 2b, and a second barrel portion 2c in order from the eyepiece side. The first barrel portion 2a is a portion on the eyepiece side of the stepped portion 2b. The stepped portion 2b is a portion that expands outward along a direction intersecting the axis of the first barrel portion 2a (for example, a direction perpendicular to the axis). The second barrel portion 2c is a portion continuous from the stepped portion 2b to the objective side and has a larger diameter than the first barrel portion 2a.

[0017] The lens barrel 2A holds lenses L1 to L6 in this order inside the barrel. The lens L1 is the lens (first lens) located on the most object side. The lens L1 is held in the second barrel portion 2c. Hereinafter, the lenses L2 to L6 are held in the first barrel portion 2a in this order from the object side toward the eyepiece side. The outer peripheral portion on the object side of the lens L2 protrudes toward the object side from the stepped portion 2b.

[0018] Note that FIG. 1 shows the optical axes X of the lenses L1 to L6. Note that the optical axis X is located on the same line as the axis of the lens barrel 2A.

[0019] The lens barrel 2A is, as an example, made of resin. The resin is, for example, a resin capable of insert molding with a conductive member (a wiring as an example). In this case, the resin may be one kind or more than one kind. Examples of such resin materials include super engineering plastics such as LENZE (registered trademark) and polyphenylene sulfide (PPS). In addition to the resin material, additives such as a plasticizer, an ultraviolet absorber, a light stabilizer, and a filler may be included. When the lens unit 101A is an in-vehicle lens unit as described above, it is used for applications related to the safety and comfort of passengers in vehicle operations such as autonomous driving, driver assistance, and peripheral monitoring. Therefore, high reliability is required for the in-vehicle lens unit. Therefore, the lens barrel 2A may be made using a super engineering plastic that has high heat resistance, durability, and dimensional stability, and also has a lower manufacturing cost compared to metal parts and is suitable for mass production.

[0020] Note that the lens barrel 2A is not limited to being made of resin and may be made of metal.

[0021] A lens reference plane is provided on the eyepiece side of the first barrel portion 2a (lens barrel 2A), and holds the lenses L1 to L6 and the filter 6.

[0022] <Lens> Lenses L1 to L6 are held at the above-described portions of the lens barrel 2A. Lens L1 is the lens (first lens) located on the most object side. Lens L2 (second lens) is the lens on the eyepiece side of lens L1. In the present embodiment, six lenses are provided, but the number of lenses included in the lens unit is not particularly limited.

[0023] The materials of lenses L1 to L6 have sufficient light transmittance, and may be one kind or more than one kind. The materials of lenses L1 to L6 can be appropriately determined from viewpoints such as being suitable for low cost and mass production. Examples of the materials of lenses L1 to L6 include glass, acrylic resin, polystyrene resin, polycarbonate resin, and polyolefin.

[0024] Here, a magnified cross-sectional view centered on lenses L1 and L2 is shown below FIG. 1. As shown below FIG. 1, on the eyepiece-side surface of lens L1, a chamfered eyepiece-side stepped portion L1c is provided over the entire periphery. A sealing member 4 is fitted into the eyepiece-side stepped portion L1c. The sealing member 4 will be described later.

[0025] <Retainer> Retainer 5 (front pressing ring) abuts against the peripheral portion of lens L1 from the object side, and presses in the axial direction of the lens barrel 2A to fix lenses L1 to L6 and filter 6 to the lens barrel 2A.

[0026] An opening 5k centered on the optical axis X is provided on the object side of retainer 5, and light can be incident on the object-side optical surface of lens L1 through the opening 5k.

[0027] Retainer 5 has, for example, a first threaded portion on its inner peripheral surface, and is fixed (screw-fastened) to the lens barrel 2A by screwing the first threaded portion into a second threaded portion formed at the object-side end of the outer peripheral surface of the lens barrel 2A. Retainer 5 presses against the peripheral portion on the object side of lens L1 and is in close contact with the peripheral portion.

[0028] The retainer 5 can be rephrased as a lens cap that axially presses the lens L1. The retainer 5 is made of resin or metal.

[0029] <Sealing member> The sealing member 4 is a sealing member arranged over the entire periphery of the lens L1 on the eyepiece side of the lens L1. The sealing member 4 is located at the corner between the stepped portion 2b and the second cylindrical portion 2c in the lens barrel 2A. The sealing member 4 is in close contact with the inner peripheral surface of the second cylindrical portion 2c, the surface of the stepped portion 2b, and the eyepiece-side peripheral portion of the lens L1 over the entire circumference, and seals the space between the lens barrel 2A and the lens L1 in a liquid-tight manner.

[0030] The sealing member 4 is a ring-shaped structure centered on the optical axis X and is arranged along the periphery of the lens L1 (first lens). When the retainer 5 is fixed to the lens barrel 2A, the sealing member 4 is crushed between the eyepiece side of the lens L1 and the stepped portion 2b. As a result, the sealing member 4 is in close contact with the inner peripheral surface of the second cylindrical portion 2c, the surface of the stepped portion 2b, and the eyepiece-side peripheral portion of the lens L1 over the entire circumference, and seals the space between the lens barrel 2A side and the optical axis X side in a liquid-tight manner with the sealing member 4 as the boundary. The sealing member 4 can be constituted by an O-ring.

[0031] There is no particular limitation on the material of the sealing member 4, but EPDM (ethylene propylene rubber), NBR (nitrile rubber), VMQ (silicone rubber), etc. can be used. Among them, from the viewpoints of the use temperature range, weather resistance, water resistance, and chemical resistance, it is preferable to use EPDM.

[0032] <Spacer> Spacers S1 to S5 are annular structures arranged between adjacent lenses. Specifically, spacer S1 is arranged between lens L1 (the first lens) and lens L2. Also, spacer S2 is arranged between lens L2 and lens L3. Also, spacer S3 is arranged between lens L3 and lens L4. Also, spacer S4 is arranged between lens L5 and lens L6. Also, spacer S5 is arranged between lens L6 and filter 6. Spacers S1 to S5 can be realized using well-known spacer materials.

[0033] Spacer S1 between lens L1 (the first lens) and lens L2 contacts lens L1 on the first surface S1a on the objective side, as shown on the lower side of FIG. 1. Also, spacer S1 contacts lens L2 on the second surface S1b on the eyepiece side. In other words, in a state where retainer 5 is fixed to lens barrel 2A, spacer S1 is sandwiched between lens L1 and lens L2.

[0034] The second surface S1b of spacer S1 includes a second lens contact region S1bA that contacts lens L2, and a step portion facing region S1bB (second lens non-contact region) that does not contact lens L2 and extends from the end of the second lens contact region S1bA toward step portion 2b and faces step portion 2b in the optical axis direction. In other words, on the second surface S1b of spacer S1, there is an annular second lens contact region S1bA along the circumference around the optical axis X closer to the optical axis X, and an annular step portion facing region S1bB on the outer peripheral side of the annular second lens contact region S1bA.

[0035] The step portion facing region S1bB is separated from the step portion 2b by a predetermined distance (Dw shown on the lower side of FIG. 1). More specifically, in a state where retainer 5 is fixed to lens barrel 2A, there is a gap of the predetermined distance Dw between the step portion facing region S1bB and the step portion 2b.

[0036] As long as the material of the spacer S1 has thermal conductivity, well-known spacers can be adopted. As an example, a metal one is preferable, and specifically, aluminum, brass, etc. can be adopted. Since these materials have a high thermal conductivity, the temperature of the heater 8 can be transferred to the lens quickly. Note that the other spacers S2 to S5 may be made of the same material as the spacer S1, or may be made of, for example, resin or the like.

[0037] The spacer S1 may be processed, for example, on the first surface S1a to prevent light reflection.

[0038] <Heater> The heater 8 is, for example, an annular heater and is fixed to the step-opposing region S1bB of the second surface S1b of the spacer S1. The heater 8 fixed to the step-opposing region S1bB is arranged to face the step 2b. The heater 8 is fixed to the step-opposing region S1bB using, for example, an adhesive.

[0039] The heater 8 heats up the lens L1 via the spacer S1. That is, the heat generated by the heater 8 is transmitted to the spacer S1 through the step-opposing region S1bB, and further transmitted from the first surface S1a of the spacer S1 to the lens L1 in contact with the first surface S1a. By heating up the lens L1 in this way, even when the temperature of the external environment of the lens unit 101A is low (for example, in a cold region), it is possible to melt the ice formed on the lens surface, for example, when the vehicle is parked, and a highly reliable lens unit can be realized.

[0040] The heater 8 is a heater having a length (the thickness of the heater 8) (8w shown on the lower side of FIG. 1) along the optical axis direction that is equal to or less than the predetermined distance Dw in a state where the heater 8 is fixed to the step-opposing region S1bB and the retainer 5 is fixed to the lens barrel 2A. A member having heat insulation or elasticity may be arranged between the heater 8 and the step 2b.

[0041] By configuring in this way, as shown in the lower part of FIG. 1, the force for fastening the lens L1 (the force for fastening to a predetermined position of the lens barrel 2A), which is associated with the retainer 5 being fixed to the lens barrel 2A, is not transmitted to the heater 8. Therefore, a failure of the heater 8 due to the fastening force does not occur. Note that the fastening force of the lens L1 and the fastening force extending to the lens L1, the spacer S1, and the lens L2 associated with the fastening of the lens L1 are schematically shown by arrows in the lower part of FIG. 1. As shown by the arrows, even when the lens L1 pushes the spacer S1 toward the eyepiece side upon fastening of the lens L1, the pushing force is only transmitted to the lens L2 via the spacer S1 and does not reach the heater 8.

[0042] In other words, a heater 8 sized to fit into the gap surrounded by the protruding outer peripheral portion on the objective side in the lens L2, the second surface S1b (step portion facing region S1bB) of the spacer S1, the second cylindrical portion 2c, and the step portion 2b is provided. This means that the heater 8 is arranged outside the outer diameter of the lens L2.

[0043] Also, if the heater 8 is mounted at the above-described location, compared with a comparative mode in which a heater is arranged between the lens on the most objective side and the lens on the eyepiece side of the said lens, only a spacer is arranged between the lenses. Therefore, according to the present embodiment, there is also an advantage that there is no adverse effect on the optical performance due to the dimensional accuracy of the heater. In short, in the case of a comparative mode where a heater is arranged between lenses, if the dimensional accuracy of the heater is poor, the distance between the lenses may change from the designed one, or the optical axes of the lenses may be displaced (eccentric). On the other hand, according to the configuration of the present embodiment, there is no such risk, and a highly accurate lens unit can be realized.

[0044] Thus, according to the configuration of this embodiment, there is no adverse effect on the optical performance due to the dimensional accuracy of the heater, and the heater 8 does not fail due to the fastening force, so advantageous effects can be obtained in terms of cost and quality. Note that there are no particular restrictions on the components for supplying power to the heater 8 and their arrangements.

[0045] As shown in FIG. 1, the heater 8 is smaller in size (surface area) than the spacer S1, and the contact area of the spacer S1 with respect to the lens L1 is larger than the case where the small heater 8 is directly in contact with the lens L1. Therefore, according to the aspect of FIG. 1, the heating area with respect to the lens L1 becomes wider than the case where the small heater 8 is directly in contact with the lens L1, and the lens L1 can be heated evenly.

[0046] Note that the heater 8 is not limited to having an annular shape when viewed along the optical axis direction, and may be an arc shape. As an example, a mode in which a plurality of arc-shaped heaters 8 are arranged side by side along the annular step 2b may be used. Alternatively, it is not limited to having an arc shape, and as long as it does not affect the other optical performance of the lens L1, a square heater that fits within the width of the step 2b may be used.

[0047] <Filter> The filter 6 is arranged on the eyepiece side of the lens unit 101A. As the filter 6, a well-known filter having optical characteristics can be adopted. As the filter 6, for example, an IR cut filter, a polarizing filter, an ND filter, a band-pass filter, etc. can be adopted.

[0048] [Manufacture of Lens Unit] As an assembly method of the lens unit 101A, a lens barrel 2A is prepared. After arranging the heater 8 on the stepped portion 2b from the opening on the object side of the lens barrel 2A, other components are inserted into the lens barrel 2A from the opening on the object side of the lens barrel 2A. That is, after inserting the filter 6 and arranging it on the eyepiece side, the spacers S5 to S1 and the lenses L6 to L1 are alternately inserted in the order shown in FIG. 1. Before arranging the lens L1, the sealing member 4 is arranged on the object side of the spacer S1. Next, the retainer 5 is fixed to the lens barrel 2A. By the above method, the lens unit 101A can be assembled.

[0049] Note that the present invention is not limited to this assembly method. For example, a method may be adopted in which the heater 8 is previously fixed to the second surface S1b of the spacer S1, and the spacer S1 is arranged on the object side of the lens L2.

[0050] [Configuration of Camera Module] FIG. 2 is a diagram schematically showing the configuration of the camera module according to the present embodiment. As shown in FIG. 2, the camera module 100 includes a lens unit 101A, a casing 102, and an imaging element 103. The camera module 100 is used for an in-vehicle camera.

[0051] The casing 102 is a housing and has an opening into which the lens barrel 2A of the lens unit 101A is inserted. The lens unit 101A is inserted into the opening and is fixed to the casing 102 in a state of abutting against the opening edge of the casing 102 at the stepped portion of the lens barrel 2A.

[0052] The imaging element 103 is fixed at a position at the bottom of the casing 102 centered on the axis of the lens barrel 2A. The imaging element 103 is an image sensor, and examples thereof include a CMOS (Complementary Metal Oxide Semiconductor) camera and a CCD (Charge Coupled Device) camera.

[0053] The camera module 100 further includes various configurations for operating the lens unit 101A. For example, the camera module 100 can further include wiring and a power source (not shown).

[0054] (Modification) In the above-described embodiment, as shown on the lower side of FIG. 1, the spacer S1 is configured to be flat from the ends closer to the optical axis X on both the first surface S1a and the second surface S1b to the ends closer to the lens barrel 2A. However, it is not limited to such a flat aspect. For example, the spacer S1 may be provided with a depression along the shape of the heater 8 on the second surface S1b.

[0055] [Embodiment 2] Another embodiment of the present invention will be described below. For convenience of explanation, members having the same functions as those described in the above embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

[0056] FIG. 3 is a cross-sectional view schematically showing the configuration of the lens unit 101B according to Embodiment 2 of the present invention. In the lens unit 101A of Embodiment 1, a chamfered eyepiece-side stepped portion L1c is provided on the eyepiece side of the lens L1 (first lens) over the entire periphery, and the sealing member 4 is fitted into the chamfered eyepiece-side stepped portion L1c. On the other hand, in the lens unit 101B of the present embodiment, there is no chamfered eyepiece-side stepped portion L1c on the eyepiece side of the lens L1 (first lens), and there is also no sealing member 4.

[0057] In addition, although the number of lenses and the total number of spacers differ between Embodiment 1 and this embodiment, the relationship between the lens L1 on the most objective side, the lens L2 on the eyepiece side thereof, the spacer S1 sandwiched therebetween, the heater 8 fixed to the spacer S1, and the lens barrel 2A and the stepped portion 2b is equivalent to that described in Embodiment 1. Therefore, similar to the lens unit 101A of Embodiment 1, in the lens unit 101B as well, there is no adverse effect on the optical performance due to the dimensional accuracy of the heater, and the heater 8 does not malfunction due to the fastening force, so advantageous effects in terms of cost and quality can be obtained. Note that in FIG. 3, for convenience of explanation, the illustration of the filter 6 shown in FIG. 1 is omitted.

[0058] 〔Embodiment 3〕 Another embodiment of the present invention will be described below. For convenience of explanation, members having the same functions as those described in the above embodiments are denoted by the same reference numerals, and the description thereof will not be repeated.

[0059] FIG. 4 is a cross-sectional view schematically showing the configuration of a lens unit 101C according to Embodiment 3 of the present invention. As shown in FIG. 4, the lens barrel 2C of the lens unit 101C has a caulking structure portion 25 at the objective-side opening, and the caulking structure portion 25 fixes each component arranged in the lens barrel 2C within the lens barrel 2C. For this reason, the lens unit 101C does not have the retainer 5 provided in the lens unit 101A of Embodiment 1.

[0060] When inserting various components arranged in the lens barrel 2C into the lens barrel 2C from the objective-side opening, the caulking structure portion 25 is in a state of rising toward the objective side. After inserting the various components into the lens barrel from the objective-side opening, by bending the caulking structure portion 25 rising toward the objective side to the optical axis side as shown in FIG. 4, the lens and the like are fixed.

[0061] Note that although the number of lenses and the total number of spacers are different between Embodiment 1 and this embodiment, the relationship between the lens L1 on the most objective side, the lens L2 on the eyepiece side thereof, the spacer S1 sandwiched therebetween, the heater 8 fixed to the spacer S1, and the lens barrel 2C and the stepped portion 2b is the same as that described in Embodiment 1. Therefore, similar to the lens unit 101A of Embodiment 1, the lens unit 101C also has no adverse effect on the optical performance due to the dimensional accuracy of the heater, and no failure of the heater 8 occurs due to the fastening force, so advantageous effects can be obtained in terms of cost and quality. Note that FIG. 4 omits the illustration of the filter 6 shown in FIG. 1 for convenience of explanation.

[0062] 〔Embodiment 4〕 Another embodiment of the present invention will be described below. For convenience of explanation, members having the same functions as those described in the above embodiments are denoted by the same reference numerals, and the description thereof will not be repeated.

[0063] FIG. 5 is a cross-sectional view schematically showing the configuration of a lens unit 101D according to Embodiment 4 of the present invention. As shown in FIG. 5, the lens unit 101D is different from Embodiment 1 in that a chamfered objective-side stepped portion L1d is provided on the outer peripheral portion of the objective-side surface L1a of the lens L1, while the eyepiece-side stepped portion L1c is provided on the outer peripheral portion of the eyepiece-side surface L1b of the lens L1 without a chamfered portion. Further, as shown in FIG. 5, the lens unit 101D is different from Embodiment 1 in that the objective-side sealing member 3 is disposed on the objective-side stepped portion L1d.

[0064] Further, as shown in FIG. 5, the lens unit 101D includes a retainer 5D having a lens contact portion 5a in contact with the object-side surface L1a of the lens L1 and a sealing member contact portion 5b in contact with the objective-side sealing member 3 in the region on the lens L1 side. Such an aspect of the retainer is also different from that of the retainer of Embodiment 1. Note that FIG. 5 omits the illustration of the filter 6 shown in FIG. 1 for convenience of explanation.

[0065] In addition, although the number of lenses and the total number of spacers are different between Embodiment 1 and this embodiment, the relationship between the lens L1 on the most objective side, the lens L2 on the eyepiece side thereof, the spacer S1 sandwiched therebetween, the heater 8 fixed to the spacer S1, and the lens barrel 2A and the step portion 2b is the same as that described in Embodiment 1. Therefore, similar to the lens unit 101A of Embodiment 1, in the lens unit 101D as well, there is no adverse effect on the optical performance due to the dimensional accuracy of the heater, and the heater 8 does not fail due to the fastening force, so that advantageous effects in terms of cost and quality can be obtained.

[0066] 〔Embodiment 5〕 Another embodiment of the present invention will be described below. For convenience of explanation, members having the same functions as those described in the above embodiments are denoted by the same reference numerals, and the description thereof will not be repeated.

[0067] FIG. 6 is a cross-sectional view schematically showing the configuration of a lens unit 101E according to Embodiment 5 of the present invention. As shown in FIG. 6, the lens unit 101E is different from Embodiment 1 having a second cylinder portion 2c without such a step portion in that the second cylinder portion 2cE at the objective-side opening of the lens barrel 2E has a step portion 2d in the middle portion thereof.

[0068] The second cylinder portion 2cE includes a lower cylinder portion continuous with the step portion 2b, a step portion 2d that is continuous with the lower cylinder portion and extends outward along a direction intersecting the optical axis X (for example, a direction perpendicular to the axis), and an upper cylinder portion on the objective-side opening side of the lens barrel 2E that is continuous with the step portion 2d.

[0069] Further, the sealing member 4 fitted into the stepped portion L1c on the eyepiece side of the lens unit 101E is in close contact and seals liquid-tightly between the upper cylinder portion, the step portion 2d, and the stepped portion L1c on the eyepiece side described above.

[0070] The outer peripheral edge of the spacer S1 is in contact with the peripheral surface of the lower cylinder portion of the second cylinder portion 2cE or is provided with a slight gap therebetween.

[0071] Although the number of lenses and the total number of spacers in Embodiment 1 and this embodiment are different, the lens L1 on the most objective side, the lens L2 on the eyepiece side thereof, the spacer S1 sandwiched therebetween, the heater 8 fixed to the spacer S1, and the relationship between the lens barrel 2E and the stepped portion 2b are the same as those described in Embodiment 1. Therefore, similar to the lens unit 101A in Embodiment 1, the lens unit 101E also has no adverse effect on the optical ability due to the dimensional accuracy of the heater, and no failure of the heater 8 occurs due to the fastening force, so advantageous effects can be obtained in terms of cost and quality. Note that, for convenience of explanation, FIG. 6 omits the illustration of the filter 6 shown in FIG. 1.

[0072] 〔Embodiment 6〕 Each of the above-described embodiments is a lens unit including a lens barrel 2A having a stepped portion 2b as shown in FIG. 1, for example. However, the present invention is not limited thereto. For example, the lens on the most objective side (first lens) and the lens on the eyepiece side of the lens (second lens) may have the same diameter, and the inner diameter of the lens barrel may be uniform in the region holding these lenses (first lens and second lens). Even in that case, if the portion near the inner peripheral surface of the lens barrel on the eyepiece side surface of the spacer (corresponding to the spacer S1 in the above-described embodiments) sandwiched by these lenses (first lens and second lens) is separated from the lens on the eyepiece side (second lens), by arranging a heater in the separated portion, an effect equivalent to the effects achieved by the above-described embodiments can be achieved.

[0073] Incidentally, as a specific example of the separated state, there may be an example in which a portion near the inner peripheral surface of the lens barrel on the eyepiece side of the spacer (corresponding to the spacer S1 in the above-described embodiment) is recessed toward the objective side. As another specific example, there may be an example in which an outer peripheral portion on the objective side of the eyepiece-side lens (second lens) is recessed toward the eyepiece side. Based on these specific examples, it is possible to provide a separated portion between the portion near the inner peripheral surface of the lens barrel on the eyepiece side of the spacer (corresponding to the spacer S1 in the above-described embodiment) and the eyepiece-side lens (second lens). A heater may be disposed in this portion.

[0074] 〔Summary〕 As is apparent from the above description, the lens unit according to the first aspect of the present invention includes a first lens on the most objective side, a second lens on the eyepiece side of the first lens, and a spacer between the first lens and the second lens, the spacer being in contact with the first lens on a first surface on the objective side and in contact with the second lens on a second surface on the eyepiece side, a lens barrel that houses at least the first lens, the second lens, and the spacer, wherein the spacer includes, on the second surface, a second lens contact region that contacts the second lens and a second lens non-contact region that is disposed in the outer diameter direction relative to the second lens contact region and does not contact the second lens, and a heater is mounted in the second lens non-contact region. According to the first aspect, the force for fastening the first lens (the force for fastening to a predetermined portion of the lens barrel) is not transmitted to the heater, and a failure of the heater due to the fastening force does not occur. Further, there is no adverse effect on the optical performance due to the dimensional accuracy of the heater. From these facts, it is possible to realize a lens unit that provides advantageous effects in terms of cost and quality.

[0075] In the lens unit according to the second aspect of the present invention, in the first aspect, the lens barrel includes a first cylindrical portion that holds the second lens, a second cylindrical portion that is on the objective side of the first cylindrical portion and has a diameter larger than that of the first cylindrical portion, and a stepped portion that is between the first cylindrical portion and the second cylindrical portion and extends outward along a direction intersecting the axis of the first cylindrical portion. The non-contact region of the spacer with respect to the second lens is a stepped portion facing region that faces the stepped portion in the optical axis direction and is spaced apart from the stepped portion by a predetermined distance along the optical axis direction. The heater is mounted in the stepped portion facing region, and the heater may have a length along the optical axis direction that is equal to or less than the predetermined distance. According to the first aspect, since a heater having a length along the optical axis direction that is equal to or less than the predetermined distance is mounted in the stepped portion facing region that is spaced apart from the stepped portion by a predetermined distance along the optical axis direction, the force for fastening the first lens (the force for fastening a predetermined portion of the lens barrel) is not transmitted to the heater, and a failure of the heater due to the fastening force does not occur. Further, there is no adverse effect on the optical performance due to the dimensional accuracy of the heater. From these aspects, a lens unit that can obtain advantageous effects in terms of cost and quality can be realized.

[0076] In the lens unit according to the third aspect of the present invention, in the first aspect or the second aspect, the heater may be disposed outside the outer diameter of the second lens. According to the third aspect, the heater fits into a void surrounded by the stepped portion facing region of the second surface of the spacer, the second cylindrical portion, and the stepped portion, which are provided outside the outer diameter of the second lens.

[0077] In the lens unit according to the fourth aspect of the present invention, in any one of the first aspect to the third aspect, the spacer may be made of metal. According to the fourth aspect, the heat conduction of the spacer is good, and the heat of the heater disposed on the second surface of the spacer is favorably transmitted to the first lens in contact with the first surface of the spacer, and the temperature of the first lens can be raised.

[0078] In the lens unit according to the fifth aspect of the present invention, in any one of the first aspect to the fourth aspect, on the outside of the optical surface of the first lens, at least one of the object side and the eyepiece side may be provided with a sealing member arranged over the entire periphery of the first lens. According to the fifth aspect, even when water enters from the object side of the lens unit into the lens barrel, the sealing member can block the water from entering the eyepiece side more than the first lens.

[0079] In the lens unit according to the sixth aspect of the present invention, in any one of the first aspect to the fifth aspect, the first lens may be fixed to the lens barrel by screw fastening of the front pressing ring, or may be fixed to the lens barrel by thermal caulking provided on the lens barrel.

[0080] The camera module according to the seventh aspect of the present invention includes any one of the lens units according to the first aspect to the sixth aspect and an image sensor. According to the sixth aspect, a highly reliable in-vehicle camera can be provided.

[0081] According to such a configuration, it is possible to provide a lens unit suitable for an in-vehicle camera. As a result, it is expected that the environment for promoting automation such as autonomous driving of automobiles will be improved. Therefore, the present invention is expected to contribute to the achievement of the Sustainable Development Goals (SDGs) related to the expansion of technological innovation and the promotion of sustainable industrialization.

[0082] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Explanation of Reference Numerals

[0083] 2A, 2C, 2E Lens barrel 2a First cylindrical portion 2b Step portion 2c, 2cE Second cylindrical portion 3 Object-side sealing member 4 Sealing member 5, 5D Retainer (front retainer ring) 6 Filter 8 Heater Length along the optical axis direction of the 8w heater (thickness of the heater) 25 Crimping structure part (front retainer ring, thermal crimping) 100 Camera module 101A, 101B, 101C, 101D, 101E Lens unit 103 Image sensor L1 Lens (first lens) L2 Lens (second lens) L3, L4, L5, L6 Lenses S1, S2, S3, S4, S5 Spacers S1bA Second lens contact area S1bB Step portion facing area Dw Separation distance between the step portion facing area of the spacer and the step portion of the lens barrel (predetermined distance)

Claims

1. A first lens located on the most object side, a second lens located on the eyepiece side of the first lens, a spacer located between the first lens and the second lens, the spacer being in contact with the first lens on a first surface on the object side and in contact with the second lens on a second surface on the eyepiece side, a lens barrel that houses at least the first lens, the second lens, and the spacer, a lens unit comprising: the spacer includes a second lens contact region that contacts the second lens on the second surface and a second lens non-contact region that is arranged in the outer diameter direction relative to the second lens contact region and does not contact the second lens, a heater is mounted in the second lens non-contact region of the lens unit, Lens unit.

2. The lens barrel is a first cylindrical portion that holds the second lens, a second cylindrical portion that is on the object side of the first cylindrical portion and has a diameter larger than that of the first cylindrical portion, a stepped portion that is between the first cylindrical portion and the second cylindrical portion and extends outward along a direction intersecting the axis of the first cylindrical portion, having, the second lens non-contact region of the spacer is a stepped portion facing region that faces the stepped portion in the optical axis direction and is a stepped portion facing region spaced apart from the stepped portion by a predetermined distance along the optical axis direction, the heater is mounted in the stepped portion facing region and has a length along the optical axis direction that is equal to or less than the predetermined distance, The lens unit according to claim 1.

3. The heater is arranged outside the outer diameter of the second lens, The lens unit according to claim 1.

4. The spacer is made of metal, The lens unit according to claim 1.

5. Outside the optical surface of the first lens, on at least one of the object side and the eyepiece side, a sealing member arranged over the entire periphery of the first lens is further provided, The lens unit according to claim 1.

6. The first lens is fixed to the lens barrel by screw fastening of a front retainer ring or is fixed to the lens barrel by thermal caulking provided on the lens barrel, The lens unit according to claim 1.

7. A camera module having the lens unit according to any one of claims 1 to 6 and an imaging element.

Images