lens unit

Abstract

A lens unit is provided in which a connecting portion of an electrode provided on a transparent conductive film and a flexible printed substrate arranged on a surface of a lens is prevented from being crushed. A lens unit (1) includes a plurality of lenses arranged along an optical axis (L) and a lens holder (2). A transparent conductive film (16) that functions as a heater is provided on an image-side lens surface (12) of a first lens (L1) arranged closest to a subject side (La). A flexible printed substrate (8) that supplies power to the transparent conductive film (16) includes a flat portion (81) along an image-side flange surface (13) that surrounds an outer periphery of the image-side lens surface (12), an extension portion (82) that extends to a radial outer side, and a protruding portion (83) that protrudes to the radial outer side from the flat portion (81). The protruding portion (83) includes a first electrode (84A) and a second electrode (84B) that are electrically connected to the transparent conductive film (16).

Description

Technical Field

[0001] This invention relates to a lens unit having multiple lenses arranged on an optical axis. Background Technology

[0002] Patent documents 1 and 2 disclose a lens unit used in an optical device. The lens unit in Patent Document 1 includes multiple lenses arranged on an optical axis and a lens holder for holding the multiple lenses. The lens holder includes a lens barrel (support unit) and a housing (outer shell) covering the lens barrel. Furthermore, a similar lens unit is disclosed in Patent Document 2.

[0003] In the lens units of Patent Documents 1 and 2, a heater is provided inside the lens unit to suppress condensation when used outdoors. For example, Patent Document 1 describes a lens unit in which a conductive film such as an ITO film formed on the lens surface is used as a heater. Patent Document 2 describes a lens unit in which a flexible printed circuit board with a heating wire (heater) is disposed between a first lens and a second lens.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 4252959

[0007] Patent Document 2: Japanese Patent Application Publication No. 2019-168509 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] In a lens unit with multiple lenses, the lens is positioned along the optical axis by bringing the outer periphery of the lens into contact with other lenses or lens barrels in the optical axis direction. Patent Document 1 describes a method where, when an ITO film is used as a heater, power is supplied using an electrode disposed on the outer periphery of the ITO film and a wiring component (connecting wire) connected to the electrode. However, if the connection between the electrode and the wiring component is sandwiched between the lens and lens barrel or other lenses, the connection is pressed, and the wiring component or electrode is crushed. This can potentially cause short circuits or other problems.

[0010] For example, in Patent Document 2, a flexible printed circuit board is used as a wiring component. When the flexible printed circuit board is used as a wiring component for supplying power to the ITO film, if the connection between the lead-out electrode of the ITO film and the flexible printed circuit board is sandwiched between a lens and a lens barrel or other lens, the connection may be crushed, causing a short circuit. For example, if a fine wiring pattern formed of a conductor is formed on the flexible printed circuit board, the wiring pattern may be crushed, causing the wirings to short-circuit with each other.

[0011] In view of the above problems, the objective of the present invention is to avoid problems such as short circuits caused by crushing of the connection portion between the electrode used to supply power to the conductive film (heater) disposed on the surface of the lens and the electrode on the flexible printed circuit board.

[0012] Technical solutions adopted to solve technical problems

[0013] To address the aforementioned technical problems, the present invention provides a lens unit, characterized by comprising: a first lens located closest to the object side; a second lens disposed on the image side relative to the first lens; a lens holder having a first receiving portion for accommodating the first lens and a second receiving portion for accommodating the second lens; a conductive film disposed on the image side side of the first lens; and a flexible printed circuit board supplying power to the conductive film, the image side side having an image side lens surface and an image side flange surface surrounding the image side lens surface, the flexible printed circuit board having a planar portion along the image side flange surface, an extension portion extending radially outward, and a protrusion portion protruding radially outward from the planar portion, the protrusion portion having an electrode electrically connected to the conductive film.

[0014] According to the present invention, since the first lens can be heated through the conductive film, condensation inside the lens unit that would degrade optical performance can be suppressed. Furthermore, in the flexible printed circuit board that supplies power to the conductive film, the electrode for connecting to the conductive film is positioned at a protruding portion extending radially outward. Therefore, interference between the electrode on the flexible printed circuit board and the connection portion of the lead-out electrode on the conductive film side in contact with the electrode is easily avoided from occurring with components (e.g., the second lens or the second receiving portion) disposed on the image side of the first lens. Consequently, the possibility of the electrode or wiring on the flexible printed circuit board being crushed between the first lens and other components (the second lens or the second receiving portion) is low, and the possibility of a short circuit resulting from crushed electrodes or wiring is low.

[0015] In this invention, preferably, the conductive film is a transparent conductive film disposed on the image-side lens surface. This allows for direct heating of the image-side lens surface of the first lens through the transparent conductive film, thereby suppressing condensation inside the lens unit and preventing a decrease in optical performance.

[0016] In this invention, preferably, the transparent conductive film has an arm disposed on the image-side flange surface, and the arm is connected to the electrode via a lead-out electrode disposed on the image-side flange surface. This reduces the likelihood of a short circuit between the electrode on the flexible printed circuit board and the transparent conductive film at locations other than the lead-out electrode.

[0017] In this invention, it is preferable to have a blackening film formed on the image-side flange surface, with the arm portion and the lead-out electrode stacked on the blackening film. This way, because the flexible printed circuit board overlaps with the blackening film, the reduction in optical performance caused by the placement of the flexible printed circuit board can be suppressed. Furthermore, because the blackening film can suppress ghosting caused by light transmitted through the image-side flange surface, the reduction in optical performance due to ghosting can be suppressed. Additionally, if unevenness (wrinkles) for light diffusion are formed on the image-side flange surface, the blackening film fills in the unevenness (wrinkles) and smooths the surface. Therefore, it is easy to form the arm portion of the transparent conductive film and the lead-out electrode on the image-side flange surface.

[0018] In this invention, preferably, the conductive film is made of a metal thin film disposed on a circumferential portion of the image-side flange surface, and the leading end of the circumferential portion of the metal thin film is connected to the electrode. This allows direct heating of the image-side flange surface of the first lens through the metal thin film. Furthermore, compared to forming the conductive film on the image-side lens surface, the impact on optical performance due to ghosting and other issues can be reduced.

[0019] In this invention, it is preferable to have a blackening film formed on the image-side flange surface, a metal thin film stacked on the blackening film, and a protective film stacked on the metal thin film, wherein the entire extent of the metal thin film, except for the front end portion, is covered by the protective film, the planar portion is annular, and the planar portion is disposed on the protective film. In this way, because the flexible printed circuit board overlaps with the blackening film, the reduction in optical performance caused by the placement of the flexible printed circuit board can be suppressed. Furthermore, because the blackening film can suppress ghosting caused by light transmitted through the image-side flange surface, the reduction in optical performance due to ghosting can be suppressed. Additionally, because the protective film is stacked on the metal thin film, the metal thin film can be protected. In particular, if a high temperature and high humidity condition occurs, the metal thin film may oxidize and crack, causing a change in resistance value, but the formation of cracks can be suppressed by providing the protective film. Therefore, changes in resistance value and changes in heat generation can be suppressed. Furthermore, when the flexible printed circuit board is disposed on the first lens, the protective film can be used as a fixing surface for the fixed planar portion.

[0020] In this invention, it is preferable that the flexible printed circuit board has a first notch adjacent to the protrusion in the circumferential direction, and the first notch is formed by cutting towards the radially inward side. By providing the notch at such a location, warping of the outer periphery of the flexible printed circuit board can be suppressed. In addition, since wiring or electrodes can be separated through the notch, the possibility of short circuits in wiring or electrodes can be reduced.

[0021] In this invention, preferably, the protrusion includes a first protrusion disposed on one circumferential side of the extension and a second protrusion disposed on the other circumferential side of the extension, with the first notch disposed between the extension and the first protrusion, and between the extension and the second protrusion. This way, since the positive and negative electrodes can be separated from the extension through the notch, short circuits in the wiring between the positive and negative electrodes and the extension are less likely. Furthermore, since the positive and negative electrodes can be concentrated near the extension, the wiring to the positive and negative electrodes can be shortened, and a simpler shape can be achieved.

[0022] In this invention, preferably, the planar portion is annular, and a connecting portion connected to the extension portion is provided in a circumferential portion of the planar portion. The flexible printed circuit board includes a second notch formed by cutting the inner periphery of the connecting portion radially outward. This reduces the possibility of short circuits between wiring connected to the electrode of the first protrusion disposed on one circumferential side of the connecting portion and wiring connected to the electrode of the second protrusion disposed on the other circumferential side of the connecting portion. Furthermore, it suppresses warping of the inner periphery of the flexible printed circuit board.

[0023] In this invention, the first and second notches are adhesive coating grooves. This improves the fixing strength when the flexible printed circuit board is fixed to the image-side flange. Furthermore, since the vicinity of the protrusion can be fixed, the electrodes disposed on the protrusion are less likely to float from the image-side flange.

[0024] In this invention, it is preferable that the flexible printed circuit board includes a heater disposed on the planar portion. This ensures that both the transparent conductive film and the heater on the flexible printed circuit board generate heat, thereby further reducing the possibility of condensation.

[0025] In this invention, preferably, the first receiving portion includes a limiting portion having a lens seat surface that abuts against the image-side flange surface and a countersunk portion recessed radially outward from the inner periphery of the limiting portion, the flat portion being disposed on the inner periphery of the limiting portion, and the protrusion being disposed on the countersunk portion. This prevents the protrusion and limiting portion, where the electrode is disposed, from interfering with each other. Therefore, the possibility of the connection portion between the electrode on the flexible printed circuit board and the lead-out electrode on the transparent conductive film side in contact with the electrode being sandwiched between the lens holder and the first lens is small. Consequently, the possibility of the wiring constituting the electrode being crushed and short-circuited is small.

[0026] Invention Effects

[0027] According to the present invention, since the first lens can be directly heated through the conductive film, condensation inside the lens unit that would degrade optical performance can be suppressed. Furthermore, in the flexible printed circuit board that supplies power to the conductive film, the electrode for connecting to the conductive film is positioned at a protruding portion extending radially outward. Therefore, interference between the electrode on the flexible printed circuit board and the connection portion of the lead-out electrode on the conductive film side in contact with the electrode is easily avoided from occurring with components (e.g., the second lens or the second receiving portion) disposed on the image side of the first lens. Consequently, the possibility of the electrode or wiring on the flexible printed circuit board being crushed between the first lens and other components (the second lens or the second receiving portion) is low, thus reducing the likelihood of a short circuit caused by crushed electrodes or wiring. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view of the lens unit according to an embodiment of the present invention.

[0029] Figure 2 yes Figure 1 A stereoscopic view of the lens unit's components.

[0030] Figure 3 This is a 3D view of the lens holder.

[0031] Figure 4 These are top views of the lens holder and the lens unit with the first lens and O-ring removed.

[0032] Figure 5 This is an explanatory diagram of the transparent conductive film, lead-out electrodes, and blackening film disposed on the first lens.

[0033] Figure 6 This is a top view of a flexible printed circuit board.

[0034] Figure 7 This is an explanatory diagram showing the arrangement of a flexible printed circuit board and lead-out electrodes in a side flange surface.

[0035] Figure 8 This is a partially enlarged cross-sectional view of the lens unit.

[0036] Figure 9 This is an explanatory diagram of the metal thin film, protective film, and blackening film disposed on the first lens.

[0037] Explanation of reference numerals in the attached figures

[0038] 1…Lens unit; 2…Lens holder; 3…Holder; 4…First receiving part; 5…Second receiving part; 6…Lens housing; 7…O-ring; 8…Flexible printed circuit board; 9…Heater; 11…Object-side lens surface; 12…Image-side lens surface; 13…Image-side flange surface; 13A…Outer peripheral region; 13B…Inner peripheral region; 14…Annular step portion; 15…Blackening film; 16…Transparent conductive film; 16A, 16B…Arm portion; 17A, 17B…Electrode; 18…Metal thin film; 18A, 18B…Front end portion; 19…Protective film; 40…Lens seat surface; 41…Annular connecting part; 42…Restricting part; 43…Peripheral wall portion; 44…Annular end face; 45…Riveting part; 46…Through hole; 47…Counterhole portion; 48…Outer edge portion; 50…Lens seat surface; 51…Cylinder portion; 52… Bottom; 53… Annular bottom surface; 54… Recess; 55… Opening; 56… Riveting part; 80A… Flexible substrate; 80B… Reinforcing plate; 81… Flat part; 82… Extension; 83… Protrusion; 83A… First protrusion; 83B… Second protrusion; 84… Electrode; 84A… First electrode; 84B… Second electrode; 85… Power supply wiring; 85A… First power supply wiring; 85B… Second power supply wiring; 86… Connecting part; 87… Arc part; 88… First notch part; 89… Second notch part; L… Optical axis; La… Object side; Lb… Image side; L1… First lens; L2… Third lens; L3… Third lens; L4… Fourth lens; L5… Fifth lens; L6… Sixth lens; L7… Light shield; L8… Aperture; L9… Joining lens; S… Gap. Detailed Implementation

[0039] Hereinafter, embodiments of the lens unit applying the present invention will be described with reference to the accompanying drawings.

[0040] (Overall structure)

[0041] Figure 1 This is a cross-sectional view of the lens unit 1 according to an embodiment of the present invention. Figure 1 In the diagram, L is the optical axis of lens unit 1. La is one side of the optical axis L, which is the object side (subject side) of lens unit 1. Lb is the other side of the optical axis L, which is the image side of lens unit 1. Lens unit 1 includes a plurality of lenses arranged in a row along the optical axis L and a lens holder 2 for holding the plurality of lenses. The plurality of lenses includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6. A light-shielding plate L7 is disposed between the second lens L2 and the third lens L3, and an aperture L8 is disposed between the third lens L3 and the fourth lens L4.

[0042] Of the multiple lenses, the first lens L1 and the fourth lens L4, located closest to the object side La, are glass lenses. The fourth lens L4 is disposed inside the lens holder 2 and fixed to the frame-shaped bracket 3. The second lens L2, the third lens L3, the fifth lens L5, and the sixth lens L6 are plastic lenses. The sixth lens L6 and the fifth lens L5, located closest to the image side Lb, constitute a combined lens L9. Furthermore, the number and structure of the lenses held in the lens holder 2 are not limited to the numbers and structures described above.

[0043] The lens holder 2 is made of resin. The lens holder 2 includes a first receiving portion 4 that holds the first lens L1, a second receiving portion 5 disposed on the image side Lb of the first receiving portion 4, and a lens housing 6 surrounding the outer periphery of the second receiving portion 5. The lens housing 6 extends from the outer periphery of the first receiving portion 4 toward the image side Lb. The second receiving portion 5 holds the second lens L2, the third lens L3, the fourth lens L4, and the joining lens L9 (the fifth lens L5 and the sixth lens L6).

[0044] Figure 2 yes Figure 1 A stereoscopic view of the dissection of lens unit 1. Figure 3 This is a 3D view of lens holder 2. Figure 4 (a) is a top view of lens holder 2. Figure 4 (b) is a top view of lens unit 1 with the first lens L1 and O-ring 7 removed. Figure 3 , Figure 4 It is an omission of the ratio Figure 1 The diagram shows the upper part (riveting part 45) of position A-A. Figure 1 , Figure 2 As shown, a first lens L1 is disposed on the lens holder 2 with reference to the inner peripheral surface of the first receiving portion 4. In addition, a second lens L2, a third lens L3, a fourth lens L4, and a joint lens L9 (a fifth lens L5 and a sixth lens L6) are disposed with reference to the inner peripheral surface of the second receiving portion 5.

[0045] The first lens L1 is positioned along the optical axis L using the lens mount surface 40 formed at the bottom of the first receiving portion 4 as a reference. For example... Figure 1 , Figure 3 As shown, the bottom of the first receiving portion 4 has an annular connecting portion 41 that is connected to the outer peripheral surface of the second receiving portion 5, an annular limiting portion 42 that protrudes from the outer peripheral side of the annular connecting portion 41 toward the object side La, and a peripheral wall portion 43 that rises from the outer peripheral edge of the limiting portion 42 toward the object side La.

[0046] like Figure 3 , Figure 4As shown, the limiting portion 42 has protrusions at multiple locations that slightly protrude from the annular end face 44 facing the object side La, and the front end face of each protrusion is a lens mount surface 40. In this configuration, the lens mount surface 40 is provided at four locations spaced approximately at equal angles around the optical axis L. The outer peripheral portion of the first lens L1 abuts against the lens mount surface 40, and the first lens L1 is riveted and fixed by a riveting portion 45 provided at the front end of the peripheral wall portion 43. The gap between the first lens L1 and the first receiving portion 4 is sealed by an O-ring 7.

[0047] like Figure 1 , Figure 2 As shown, the second receiving portion 5 includes a cylindrical portion 51 connected to the annular connecting portion 41 of the first receiving portion 4 and a bottom portion 52 disposed at the image-side Lb end of the cylindrical portion 51 extending along the optical axis L. The second lens L2, the third lens L3, the fourth lens L4, and the combined lens L9 (the fifth lens L5 and the sixth lens L6) are formed on the lens mount surface 50 of the bottom 52 of the second receiving portion 5 (see reference). Figure 3 , Figure 4 (a) is positioned in the direction of the optical axis L as a reference.

[0048] The bottom 52 of the second receiving portion 5 has protrusions at multiple locations that slightly protrude from the annular bottom surface 53 facing the object side La, and the front end surface of each protrusion is a lens seat surface 50. For example... Figure 4 As shown in (a), in this embodiment, lens mount surfaces 50 are provided at three locations spaced approximately at equal angles around the optical axis L. Additionally, the second receiving portion 5 includes a recess 54 recessed to the image side Lb at a predetermined depth on the inner circumferential side of the annular bottom surface 53, and a circular opening 55 located at the center of the recess 54.

[0049] The fifth lens L5 abuts against the lens mount surface 50, and the joining lens L9 is positioned in the optical axis L direction. The sixth lens L6, which is located closest to the image side Lb, is accommodated inside the recess 54, but does not contact the inner surface of the recess 54. Instead, it is positioned in the optical axis L direction via the fifth lens L5.

[0050] The fourth lens L4, located on the object side La of the bonding lens L9, is held in place by the bracket 3, which abuts against the outer peripheral portion of the fifth lens L5 in the optical axis L direction. Furthermore, the outer peripheral portion of the third lens L3, located on the object side La of the fourth lens L4, abuts against the outer peripheral portion of the bracket 3 in the optical axis L direction via the aperture L8. Additionally, the outer peripheral portion of the second lens L2, located on the object side La of the third lens L3, abuts against the outer peripheral portion of the third lens L3 in the optical axis L direction via the light-shielding plate L7. Therefore, the second lens L2, the third lens L3, and the fourth lens L4 are all positioned in the optical axis L direction with the lens mount surface 50 as a reference. The second lens L2 is riveted and fixed by a riveting portion 56 provided at the end of the cylindrical portion 51 on the object side La.

[0051] (Transparent conductive film)

[0052] Lens unit 1 includes a transparent conductive film 16 disposed on the surface of the first lens L1. The transparent conductive film 16 is a resistive element that heats up when energized, acting as a heater to directly heat the first lens L1. Figure 1 , Figure 2 As shown, the first lens L1 includes an object-side lens surface 11 protruding towards the object side La, an image-side lens surface 12 recessed towards the object side La, an image-side flange surface 13 surrounding the outer periphery of the image-side lens surface 12, and an annular step portion 14 recessed towards the object side La on the outer periphery of the image-side flange surface 13. The image-side flange surface 13 is an annular flat surface perpendicular to the optical axis L. An O-ring 7 is disposed in the annular step portion 14.

[0053] Figure 5 This is an explanatory diagram of the transparent conductive film 16, the lead-out electrodes 17A and 17B, and the blackening film 15 disposed on the first lens L1. Figure 5 (a)~ Figure 5 (d) is a top view of the first lens L1 as seen from the image side Lb. Figure 5 (a) represents the planar shape of the blackening film 15. Figure 5 (b) indicates the planar shape of the transparent conductive film 16. Figure 5 (c) indicates the planar shape of the lead-out electrodes 17A and 17B. Figure 5 (d) indicates the state in which the transparent conductive film 16, lead-out electrodes 17A and 17B and blackening film 15 are stacked on the image-side lens surface 12 and the image-side flange surface 13.

[0054] The image-side flange surface 13 is a light-diffusing surface, and minute irregularities (wrinkles) are formed on its entire surface. In this embodiment, a blackening film 15 is formed on the image-side flange surface 13. The blackening film 15 is formed, for example, by applying ink. Since the first lens L1 diffuses light through the minute irregularities (wrinkles) and absorbs light through ink application, the degradation of optical performance due to ghosting can be suppressed. Figure 5 As shown in (a), the blackening film 15 is formed on almost the entire surface of the image side flange surface 13.

[0055] A transparent conductive film 16 is disposed on the image-side lens surface 12. In this embodiment, the transparent conductive film 16 is an ITO film. The deposition process of the transparent conductive film 16 relative to the image-side lens surface 12 is performed after the blackening film 15 is formed on the image-side flange surface 13. In the lens unit 1, the image-side lens surface 12 is uniformly heated by energizing the transparent conductive film 16. Power is supplied to the transparent conductive film 16 via lead-out electrodes 17A and 17B disposed on the image-side flange surface 13.

[0056] like Figure 5As shown in (b), the transparent conductive film 16 has two arms 16A and 16B disposed on the image-side flange surface 13. Arms 16A and 16B extend radially in opposite directions from the outer periphery of the image-side lens surface 12. Lead-out electrodes 17A and 17B are arranged symmetrically about the optical axis L. Lead-out electrode 17B extends circumferentially in an arc shape with the front end of arm 16B as the center. Arms 16A and 16B and lead-out electrodes 17A and 17B are stacked on the blackening film 15.

[0057] (Flexible printed circuit board)

[0058] like Figure 1 , Figure 2 As shown, the lens unit 1 includes a flexible printed circuit board 8. The flexible printed circuit board 8 extends radially outward from between the first lens L1 and the second lens L2 and is bent at approximately a right angle, passing through a through hole 46 formed on the first receiving portion 4 of the lens holder 2, and is led out to the image side Lb of the lens holder 2.

[0059] A power supply wiring 85 and an electrode 84 for supplying power to the transparent conductive film 16 are disposed on the flexible printed circuit board 8. Additionally, a heater 9 is disposed on the flexible printed circuit board 8. That is, in this embodiment, heating elements (heaters) are respectively provided at both the first lens L1 and the flexible printed circuit board 8.

[0060] Figure 6 This is a top view of the flexible printed circuit board 8. The flexible printed circuit board 8 includes an annular planar portion 81 along the image-side flange surface 13, an extension portion 82 extending linearly from the planar portion 81 toward the radially outward direction, and protrusions 83 protruding radially outward from the planar portion 81 on both sides of the extension portion 82 in the circumferential direction. A heater 9 is disposed in the planar portion 81. The area where the heater 9 is disposed, for example, is... Figure 6 Region B is enclosed by a dashed line. A pattern of conductive material that heats up when electricity is applied is formed in region B (illustration omitted).

[0061] An electrode 84 is disposed on the protrusion 83 of the flexible printed circuit board 8, and the electrode 84 is electrically connected to the lead-out electrodes 17A and 17B disposed on the first lens L1. Additionally, a power supply line 85 connected to the electrode 84 and the heater 9 is disposed on the extension 82. More specifically, the protrusion 83 has a first protrusion 83A disposed on one side of the extension 82 in the circumferential direction and a second protrusion 83B disposed on the other side of the extension 82 in the circumferential direction. The electrode 84 has a first electrode 84A disposed on the first protrusion 83A and a second electrode 84B disposed on the second protrusion 83B. The power supply line 85 has a first power supply line 85A connected to the first electrode 84A and a second power supply line 85B connected to the second electrode 84B. One of the first electrode 84A and the second electrode 84B is a positive electrode, and the other of the first electrode 84A and the second electrode 84B is a negative electrode.

[0062] The planar portion 81 of the flexible printed circuit board 8 includes a connecting portion 86 disposed radially inward of the extension portion 82 and arcuate portions 87 extending circumferentially on both sides of the connecting portion 86. The arcuate portions 87 are connected to the extension portion 82 via the connecting portion 86. Protrusions 83 protrude radially outward from the arcuate portions 87 on both sides of the connecting portion 86 in the circumferential direction.

[0063] The first power supply line 85A and the second power supply line 85B extend substantially parallel to each other in an electrically insulated manner at the extension 82, and extend in opposite directions in the circumferential direction at the connecting portion 86. The first power supply line 85A, extending circumferentially to one side, extends radially outward toward the first protrusion 83A and connects to the first electrode 84A. Conversely, the second power supply line 85B, extending circumferentially to the other side, extends radially outward toward the second protrusion 83B and connects to the second electrode 84B. Furthermore, in... Figure 6 The diagram only shows the arrangement area of ​​electrode 84 and power supply wiring 85; detailed structures of electrode 84 and power supply wiring 85 are omitted. Electrode 84 can be disposed on protrusion 83, and its arrangement area is not limited to this. Figure 6 The area shown. Furthermore, the configuration area for power supply wiring 85 is not limited to... Figure 6 The area shown.

[0064] The flexible printed circuit board 8 includes a flexible substrate 80A made of a resin film such as polyimide and a pattern of wiring or electrodes formed on the flexible substrate 80A using a conductive material such as Cu. In this embodiment, electrodes 84 for energizing the transparent conductive film 16, power supply wiring 85 for energizing the transparent conductive film 16 and the heater 9, and a pattern of conductive material that functions as the heater 9 are formed on the flexible substrate 80A. The conductive material pattern is coated onto the surface of the flexible substrate 80A. However, a portion of the conductive material pattern is exposed and not coated. For example, the electrodes 84 for electrical connection with the transparent conductive film 16 are not covered by the coating.

[0065] The flexible printed circuit board 8 includes a first notch 88 formed by making a straight cut in the radially inward direction at the portion adjacent to the protrusion 83 in the circumferential direction. More specifically, the first notch 88 is provided at two locations: between the first protrusion 83A and the extension 82, and between the second protrusion 83B and the extension 82. By providing the first notch 88, warping of the first protrusion 83A and the second protrusion 83B is suppressed. In addition, the electrode 84 and the power supply wiring 85 are less prone to short circuits.

[0066] Furthermore, the flexible printed circuit board 8 includes a second notch 89 formed by making a straight cut along the inner periphery of the connecting portion 86 radially outward. The second notch 89 is located approximately at the center of the circumference of the extension 82 and is disposed between the first power supply line 85A and the second power supply line 85B. By providing the second notch 89, warping of the connecting portion 86 is suppressed, and short circuits between the first power supply line 85A and the second power supply line 85B are less likely to occur.

[0067] In this configuration, the first notch 88 and the second notch 89 are used as adhesive coating grooves. When assembling the lens unit 1, the flexible printed circuit board 8 is fixed to the image-side flange surface 13 by the adhesive disposed in the first notch 88 and the second notch 89.

[0068] Figure 7 This is an explanatory diagram showing the arrangement of the flexible printed circuit board 8 and the lead electrodes 17A and 17B in the side flange surface 13. (See diagram below.) Figure 7 As shown, when fixing the planar portion 81 of the flexible printed circuit board 8 to the image-side flange surface 13, the planar portion 81 is positioned such that the center of the image-side flange surface 13 coincides with the center of the planar portion 81. The shape of the planar portion 81 is set to a shape that has little impact on the optical performance of the lens unit 1. In this embodiment, the inner diameter D1 of the planar portion 81 is a predetermined size (e.g., 0.4 mm) larger than the inner diameter D2 of the image-side flange surface 13. Therefore, the possibility of the inner periphery of the planar portion 81 being exposed inside the image-side lens surface 12, thus reducing the optical performance, is small.

[0069] When the planar portion 81 is fixed to the image-side flange surface 13, the planar portion 81 is positioned in the circumferential direction so that the second notch portion 89, which is located at the center in the width direction of the extension portion 82, is positioned at the center of the circumferential gap between the two lead-out electrodes 17A and 17B. Thus, the first electrode 84A and the lead-out electrode 17A overlap, and the second electrode 84B and the lead-out electrode 17B overlap. Therefore, the power supply wiring 85 is electrically connected to the transparent conductive film 16 via the arms 16A and 16B and the lead-out electrodes 17A and 17B.

[0070] In this configuration, since the lead-out electrodes 17A and 17B extend circumferentially, the power supply positions to lead-out electrodes 17A and 17B can be made close together. Therefore, the first electrode 84A and the second electrode 84B, which are connected to lead-out electrodes 17A and 17B, can be concentrated near the extension portion 82. This shortens the power supply wiring 85 provided between the extension portion 82 and the first electrode 84A and the second electrode 84B, and allows for a simpler shape.

[0071] (Positioning of the first lens along the optical axis L)

[0072] Figure 8 This is a partially enlarged cross-sectional view of lens unit 1. Figure 4 (b) Diagram showing the C-C cutoff point. (See diagram below.) Figure 8 As shown, the lens holder 2 has a limiting portion 42 protruding from the bottom of the first receiving portion 4 towards the object side La. The image-side flange surface 13 of the first lens L1 has an outer peripheral region 13A that abuts against the lens seat surface 40 disposed at the front end of the limiting portion 42. In addition, the image-side flange surface 13 has an inner peripheral region 13B located on the inner peripheral side of the outer peripheral region 13A, and the planar portion 81 of the flexible printed circuit board 8 is disposed in the inner peripheral region 13B.

[0073] When the first lens L1 is installed into the first receiving part 4, as Figure 4 (b) Figure 8 As shown, the planar portion 81 disposed in the inner peripheral region 13B of the image-side flange surface 13 is disposed on the inner peripheral side of the limiting portion 42. Therefore, the planar portion 81 will not interfere with the limiting portion 42, and the flexible printed circuit board 8 will not be sandwiched between the first lens L1 and the lens holder 2. In this configuration, the position of the first lens L1 in the optical axis L direction is defined by the direct contact between the outer peripheral region 13A of the image-side flange surface 13 and the lens seat surface 40.

[0074] like Figure 8As shown, the planar portion 81 of the flexible printed circuit board 8 extends radially outward from the riveting portion 56 that fixes the outer periphery of the second lens L2. In this configuration, the gap S between the riveting portion 56 and the inner peripheral region 13B of the image-side flange surface 13 in the optical axis L direction is greater than the thickness of the flexible printed circuit board 8. Therefore, the planar portion 81 does not interfere with the riveting portion 56, and the flexible printed circuit board 8 is not sandwiched between the first lens L1 and the riveting portion 56.

[0075] (Counter-sunken section)

[0076] like Figure 2 , Figure 3 , Figure 4 As shown, the first receiving portion 4 has a countersunk portion 47 that is recessed radially outward from the inner periphery of the limiting portion 42. As... Figure 4 As shown in (b), the extension 82 and protrusion 83 of the flexible printed circuit board 8 are disposed in the countersunk hole portion 47. Additionally, as... Figure 2 As shown, the extension 82 bends towards the image side Lb midway through its radially outward extension and is inserted into the slit-shaped through hole 46, which is an opening on the bottom surface of the countersunk hole 47. Therefore, the extension 82 and the protrusion 83 do not interfere with the limiting portion 42. Furthermore, the extension 82 may also include a reinforcing plate 80B fixed to the flexible substrate 80A. When the reinforcing plate 80B is included, it is disposed within the through hole 46.

[0077] like Figure 1 , Figure 2 As shown, the through hole 46 extends through the bottom of the first receiving portion 4 along the optical axis L, communicating with the gap between the cylindrical portion 51 of the second receiving portion 5 and the lens housing 6. The inner circumferential surface of the lens housing 6 is recessed in shape along the radially outer edge of the through hole 46. The extension 82 inserted into the through hole 46 passes through the gap between the inner circumferential surface of the lens housing 6 and the outer circumferential surface of the cylindrical portion 51, and is led out to the image side Lb of the lens holder 2.

[0078] In this method, the extension 82 is not fixed in the through hole 46, but an adhesive can be placed in the through hole 46 to fix the extension 82 to the through hole 46. In this case, by pre-forming unevenness on the inner circumferential surface of the through hole 46, the bonding area can be increased, and the fixing strength of the extension 82 can be improved.

[0079] The limiting portion 42 includes an outer edge 48 extending circumferentially outward from the countersunk portion 47. The outer edge 48 is connected to lens mount surfaces 40 provided on both circumferential sides of the countersunk portion 47. Therefore, in this configuration, the limiting portion 42 is generally annular and is opposed to the outer periphery of the first lens L1 throughout the circumferential direction. Thus, since the O-ring 7 disposed on the outer periphery of the first lens L1 is supported by the limiting portion 42 throughout the circumferential direction, the O-ring 7 is prevented from falling into the inner side of the countersunk portion 47, thereby reducing the sealing performance.

[0080] (The main effects of this method)

[0081] As described above, the lens unit 1 of this embodiment includes a first lens L1 located closest to the object side La, a second lens L2 disposed on the image side Lb relative to the first lens L1, a lens holder 2 having a first receiving portion 4 for accommodating the first lens L1 and a second receiving portion 5 for accommodating the second lens L2, a transparent conductive film 16 (conductive film) disposed on the image-side lens surface 12 of the first lens L1, and a flexible printed circuit board 8 for supplying power to the transparent conductive film 16. The first lens L1 has an image-side flange surface 13 surrounding the image-side lens surface 12. The flexible printed circuit board 8 has a planar portion 81 along the image-side flange surface 13, an extension portion 82 extending radially outward, and a protrusion portion 83 protruding radially outward from the planar portion 81. The protrusion portion 83 has electrodes 84 (first electrode 84A, second electrode 84B) electrically connected to the transparent conductive film 16.

[0082] In this method, since the first lens L1 can be directly heated through the transparent conductive film 16, condensation inside the lens unit 1, which would otherwise reduce optical performance, can be suppressed. Furthermore, in the flexible printed circuit board 8 that supplies power to the transparent conductive film 16, the electrode 84 connected to the transparent conductive film 16 is disposed on a radially outwardly protruding portion 83. Therefore, it is easy to avoid interference between the electrode 84 (first electrode 84A, second electrode 84B) on the flexible printed circuit board 8 and the connection portions of the lead-out electrodes 17A, 17B in contact with the electrode 84 and components disposed on the image side Lb of the first lens L1 (e.g., the second lens L2 or the second receiving portion 5). Consequently, the possibility of the electrode 84 or wiring on the flexible printed circuit board 8 being crushed between the first lens L1 and other components (the second lens L2 or the second receiving portion 5) is low, and the possibility of a short circuit due to crushed electrode 84 or wiring is also low.

[0083] For example, in this embodiment, the planar portion 81 of the flexible printed circuit board 8 extends radially outward from the riveting portion 56 that fixes the outer periphery of the second lens L2 (see reference). Figure 8Therefore, the protrusion 83, which is located radially outward from the outer periphery of the planar portion 81, is positioned radially outward from the riveting portion 56 and will not interfere with it. Thus, the connection portions of the electrode 84 located on the protrusion 83 and the lead-out electrodes 17A and 17B in contact with it will not be crushed between the riveting portion 56 and the first lens L1. Consequently, the possibility of short circuits caused by crushing of wiring or the electrode 84 on the flexible printed circuit board 8 is low.

[0084] Furthermore, in this embodiment, the first receiving portion 4 accommodating the first lens L1 includes a limiting portion 42 having a lens seat surface 40 that abuts against the image-side flange surface 13, and a countersunk portion 47 recessed radially outward from the inner periphery of the limiting portion 42. The planar portion 81 of the flexible printed circuit board is disposed on the inner periphery of the limiting portion 42, and the protrusion 83 is disposed in the countersunk portion 47. Therefore, the protrusion 83, where the electrode 84 is disposed, will not interfere with the limiting portion 42. Thus, in this embodiment, because the bottom of the first receiving portion 4 is shaped to avoid interference with the protrusion 83 where the electrode 84 is disposed, the possibility of the electrode 84 on the flexible printed circuit board 8 and the connection portions of the lead electrodes 17A and 17B that contact the electrode 84 being sandwiched between the lens holder 2 and the first lens L1 is small. Consequently, the possibility of the electrode 84 or wiring on the flexible printed circuit board 8 being crushed and causing a short circuit is small.

[0085] In this embodiment, the flexible printed circuit board 8 has a first notch 88 adjacent to the protrusion 83 in the circumferential direction. Because the first notch is formed by cutting towards the radially inward side, warping of the outer periphery of the flexible printed circuit board 8 can be suppressed. In addition, because the electrode 84 provided on the protrusion 83 is separate from other wirings or electrodes, the possibility of short circuit between the electrode 84 and other wirings or electrodes is small.

[0086] In this embodiment, the protrusion 83 of the flexible printed circuit board 8 includes a first protrusion 83A disposed on one side of the extension 82 in the circumferential direction and a second protrusion 83B disposed on the other side of the extension 82 in the circumferential direction. Therefore, since the positive and negative electrodes 84 (first electrode 84A, second electrode 84B) can be concentrated on both sides of the extension 82, the wiring to the positive and negative electrodes 84 can be shortened, and a simple shape can be achieved. Furthermore, a first notch 88 is disposed between the extension 82 and the first protrusion 83A, and between the extension 82 and the second protrusion 83B. Therefore, since the wiring of the extension 82 and the positive and negative electrodes 84 can be separated by the first notch 88, the possibility of a short circuit between the wiring of the extension 82 and the positive and negative electrodes 84 is low.

[0087] In this embodiment, the planar portion 81 of the flexible printed circuit board 8 is annular, and a connecting portion 86 connected to the extension portion 82 is provided on a portion of the circumferential direction of the planar portion 81. Because the flexible printed circuit board 8 has a second notch 89 formed by cutting the inner periphery of the connecting portion 86 radially outward, warping of the inner periphery of the flexible printed circuit board 8 can be suppressed. In addition, the possibility of short circuits in the wiring disposed in the connecting portion 86 is small. For example, the possibility of short circuits between the first power supply wiring 85A disposed on one circumferential side of the connecting portion 86 and the second power supply wiring 85B disposed on the other circumferential side of the connecting portion 86 is small.

[0088] In this configuration, the first notch 88 and the second notch 89 serve as adhesive coating grooves for applying the adhesive used to fix the flexible printed circuit board 8 to the first lens L1. By placing the adhesive in the grooves of the flexible printed circuit board 8, the fixing strength of the flexible printed circuit board 8 can be improved. Furthermore, the vicinity of the protrusion 83 can be fixed, thus preventing the electrode 84 disposed on the protrusion 83 from easily floating off the image-side flange surface 13.

[0089] In this configuration, the transparent conductive film 16 has arms 16A and 16B disposed on the image-side flange surface 13. Arms 16A and 16B are connected to the electrode 84 via lead-out electrodes 17A and 17B disposed on the image-side flange surface 13. Therefore, when connecting the transparent conductive film 16 and the flexible printed circuit board 8, the possibility of a short circuit between the portion other than the lead-out electrodes 17A and 17B and the electrode 84 is small.

[0090] In this embodiment, a blackening film 15 is formed on the image-side flange surface 13 of the first lens L1, and the arms 16A, 16B and the lead-out electrodes 17A, 17B are stacked on the blackening film 15. Therefore, since the blackening film 15 is formed on the surface overlapping with the flexible printed circuit board 8, the reduction in optical performance caused by the flexible printed circuit board 8 being placed on the image-side flange surface 13 can be suppressed. In addition, since the blackening film 15 can suppress ghosting caused by light transmitted through the image-side flange surface 13, the reduction in optical performance caused by ghosting can be suppressed. Moreover, if the image-side flange surface 13 has irregularities (wrinkles) for light diffusion, the blackening film 15 fills in the irregularities (wrinkles) and smooths the surface. Therefore, the arms 16A, 16B of the transparent conductive film 16 and the lead-out electrodes 17A, 17B can be easily formed on the image-side flange surface 13.

[0091] In this method, since the flexible printed circuit board 8 has a heater 9 disposed on the planar portion 81, both the transparent conductive film 16 and the heater 9 on the flexible printed circuit board 8 can be heated. Therefore, the possibility of condensation can be further reduced.

[0092] (Example of a modified conductive film)

[0093] The above method involves placing a transparent conductive film 16, such as an ITO film, as a conductive film that directly heats the first lens L1 on the image-side surface (image-side lens surface 12, image-side flange surface 13) of the first lens L1. However, it is also possible to use a structure in which other conductive films are placed on the image-side surface of the first lens L1. Figure 9 This is an explanatory diagram of the metal thin film 18, the protective film 19, and the blackening film 15 disposed on the first lens L1. Figure 9 (a)~ Figure 9 (d) is a top view of the first lens L1 as seen from the image side Lb. Figure 9 (a) represents the planar shape of the blackening film 15. Figure 9 (b) represents the planar shape of the metal thin film 18. Figure 9 (c) indicates the planar shape of the protective film 19. Figure 9 (d) indicates the state in which the metal thin film 18, the protective film 19 and the blackening film 15 are stacked on the image-side flange surface 13.

[0094] The metal thin film 18 is a conductive film disposed on the image-side flange surface 13 of the first lens L1. The metal thin film 18 is, for example, a laminated film formed by stacking NiFe films, Ni films, or Cr films, or Ni and Cr films. The metal thin film 18 is stacked on the blackening film 15. Figure 9 As shown in (b), the metal film 18 is disposed on a portion of the circumferential direction of the image-side flange surface 13. In this configuration, the metal film 18 extends in an arc shape on the image-side flange surface 13, forming a C-shaped planar shape. The front end portion 18A on one side of the circumferential direction of the metal film 18 and the front end portion 18B on the other side of the circumferential direction of the metal film 18 are spaced apart by a predetermined gap and face each other in the circumferential direction.

[0095] The protective film 19 has low moisture permeability, thus protecting the metal film 18 from moisture. The protective film 19 is preferably a non-conductive film such as a SiO2 film. The protective film 19 is laminated on the metal film 18. Figure 9 As shown in (c), the protective film 19, like the metal film 18, is formed in a C-shaped planar shape. The protective film 19 extends over the entire radial range from the inner to the outer periphery of the image-side flange surface 13, but the angular range where the protective film 19 is disposed is smaller than the angular range where the metal film 18 is disposed. Therefore, as... Figure 9 As shown in (d), except for the front ends 18A and 18B, the entire extent of the metal film 18 is covered by the protective film 19.

[0096] In the lens unit 1, the image-side flange surface 13 is heated by energizing the metal thin film 18. Power is supplied to the metal thin film 18 via the exposed front portions 18A and 18B of the protective film 19. When the planar portion 81 of the flexible printed circuit board 8 is placed on the protective film 19 disposed on the image-side flange surface 13, the electrode 84 provided on the protrusion 83 protruding from the planar portion 81 contacts the front portions 18A and 18B of the metal thin film 18. Therefore, the metal thin film 18 is energized via the electrode 84.

[0097] Thus, in Figure 9 In the modified example shown, the conductive film disposed on the image-side surface of the first lens L1 is composed of a metal thin film 18. The metal thin film 18 is disposed on a portion of the circumferential direction of the image-side flange surface 13, and the circumferentially front ends 18A and 18B of the metal thin film 18 are connected to the power supply electrode 84 disposed on the flexible printed circuit board 8. Therefore, since the image-side flange surface 13 of the first lens can be directly heated through the metal thin film 18, condensation inside the lens unit 1, which would otherwise reduce optical performance, can be suppressed. In addition, compared with the case where a transparent conductive film 16 is formed on the image-side lens surface 12, the impact on optical performance due to ghosting and the like can be reduced.

[0098] In addition, Figure 9 In the modified example shown, a blackening film 15 is formed on the image-side flange surface 13 of the first lens L1, and a metal thin film 18 is stacked on the blackening film 15. Furthermore, a protective film 19 is stacked on the metal thin film 18, covering the entire area of ​​the metal thin film 18 except for its front end. Additionally, the planar portion 81 is annular and is disposed on the protective film 19. Therefore, similarly to the above, the flexible printed circuit board 8 overlaps with the blackening film 15, thus suppressing the degradation of optical performance caused by the placement of the flexible printed circuit board 8. Furthermore, since the blackening film 15 can suppress ghosting caused by light transmitted through the image-side flange surface 13, the degradation of optical performance caused by ghosting can be suppressed. Moreover, the protective film 19 protects the metal thin film 18, improving environmental resistance. In particular, if the environment becomes hot and humid, the metal film 18 may oxidize and crack, causing a change in resistance. However, by protecting the metal film 18 with the protective film 19, the formation of cracks can be suppressed. Therefore, the change in the resistance of the metal film 18 can be suppressed, thereby suppressing deviations in heat generation. Furthermore, when the flexible printed circuit board 8 is placed on the first lens, the protective film 19 can be used as a fixing surface for the fixing plane portion 81.

[0099] (Other variations)

[0100] (1) In the above method, a heater 9 is provided on the planar portion 81 of the flexible printed substrate 8, but the heater 9 may not be provided. The flexible printed substrate 8 only has a power supply wiring 85 and an electrode 84 for supplying power to the transparent conductive film 16 or the metal film 18.

[0101] (2) In the above manner, the planar portion 81 of the flexible printed substrate is annular, but it may also be a shape in which a portion of the circumferential portion 81 is missing.

Claims

1. A lens unit, characterized in that, have: The first lens is positioned closest to the object side; The second lens is disposed on the image side relative to the first lens; A lens holder, the lens holder having a first receiving portion for receiving the first lens and a second receiving portion for receiving the second lens; A conductive film is disposed on the image-side surface of the first lens; as well as A flexible printed circuit board that supplies power to the conductive film. The image-side surface has an image-side lens surface and an image-side flange surface surrounding the image-side lens surface. The conductive film is a transparent conductive film. The transparent conductive film is disposed on the image-side lens surface and has an arm disposed on the image-side flange surface. The flexible printed circuit board includes a planar portion along the image-side flange surface, an extension portion extending radially outward, and a protrusion portion protruding radially outward from the planar portion. The protrusion has an electrode that is electrically connected to the conductive film. The arm is connected to the electrode via an outgoing electrode disposed on the image-side flange surface.

2. The lens unit according to claim 1, characterized in that, It has a blackening film formed on the image side flange surface. The arm portion and the lead-out electrode are stacked on the blackening film.

3. The lens unit according to claim 1, characterized in that, The conductive film is composed of a thin metal film. The metal thin film is disposed on a portion of the circumferential direction of the image-side flange surface. The circumferential front end of the metal thin film is connected to the electrode.

4. The lens unit according to claim 3, characterized in that, It has a blackening film formed on the image side flange surface. The metal film is laminated on the blackened film. A protective film is laminated on the metal film, covering the entire extent of the metal film except for the front end. The planar portion is annular and is disposed on the protective film.

5. The lens unit according to any one of claims 1 to 4, characterized in that, The flexible printed circuit board has a first notch adjacent to the protrusion in the circumferential direction. The first notch is formed by cutting inward toward the radial side.

6. The lens unit according to claim 5, characterized in that, The protrusion includes a first protrusion disposed on one circumferential side of the extension and a second protrusion disposed on the other circumferential side of the extension. The first notch is disposed between the extension and the first protrusion, and between the extension and the second protrusion.

7. The lens unit according to claim 6, characterized in that, The planar portion is ring-shaped. A connecting portion that connects to the extension is provided in a portion of the circumferential direction of the planar portion. The flexible printed circuit board has a second notch formed by cutting the inner periphery of the connecting portion radially outward.

8. The lens unit according to claim 7, characterized in that, The first notch and the second notch are adhesive coating grooves.

9. The lens unit according to any one of claims 1 to 4, characterized in that, The flexible printed circuit board includes a heater disposed on the planar portion.

10. The lens unit according to any one of claims 1 to 4, characterized in that, The first receiving portion includes a limiting portion having a lens seat surface that abuts against the image-side flange surface and a countersunk portion that is recessed radially outward from the inner periphery of the limiting portion. The planar portion is disposed on the inner peripheral side of the limiting portion. The protrusion is disposed in the countersunk hole portion.

Images