Lens unit
A lens unit 1 includes a plurality of lenses aligned in a row along an optical axis L and a lens holder 2. A transparent conductive film 16, which functions as a heater, is disposed on an image-side lens surface 12 of the first lens L 1 disposed the closest to an object side La. A flexible printed circuit board 8 that feeds power to the transparent conductive film 16 includes a flat surface portion 81 along an image-side flange surface 13 surrounding an outer peripheral side of the image-side lens surface 12, an extension portion 82 extending to an outer side in a radial direction, and a protruding portion 83 projecting to the outer side in the radial direction from the flat surface portion 81. The protruding portion 83 includes a first electrode 84 A and a second electrode 84 B electrically connected to the transparent conductive film 16.
1 . A lens unit comprising:
a first lens located the closest to an object side;
a second lens disposed on an image side with respect to the first lens;
a lens holder including a first housing portion that accommodates the first lens and a second housing portion that accommodates the second lens;
a transparent conductive film disposed on an image-side surface of the first lens; and
a flexible printed circuit board that feeds power to the transparent conductive film,
wherein the image-side surface of the first lens includes an image-side lens surface and an image-side flange surface that surrounds the image-side lens surface,
the image-side lens surface of the first lens is concave and forms an optically active portion, and the image-side flange surface of the first lens is an annular flat surface perpendicular to the optical axis,
the transparent conductive film has a portion disposed on the optically active portion of the first lens and arm portions disposed on the image-side flange surface of the first lens,
the flexible printed circuit board includes a flat surface portion along the image-side flange surface of the first lens, an extension portion that extends to an outer side in a radial direction; and a protruding portion that project to the outer side in the radial direction from the flat surface portion,
the protruding portion of the flexible printed circuit board includes an electrode electrically connected to the transparent conductive film,
the arm portions of the transparent conductive film are connected to the electrode via extraction electrodes disposed on the image-side flange surface of the first lens,
the transparent conductive film is a resistive element that generates heat when energized, and is a heater that directly heats the first lens,
power is fed to the transparent conductive film via the extraction electrodes,
the first housing portion of the lens holder includes a recess and a regulation portion having a face in a direction perpendicular to the optical axis, the image-side flange surface being in contact with the face,
the recess extends toward the outer side in the radial direction from an inner peripheral edge of the regulation portion,
the flat surface portion of the flexible printed circuit board is disposed on an inner peripheral side of the regulation portion of the first housing portion, and
the protruding portion of the flexible printed circuit board is disposed on the recess of the first housing portion.
2 . The lens unit according to claim 1 , further comprising: a blackened film formed on the image-side flange surface, wherein the arm portions and the extraction electrodes are stacked on top of the blackened film.
3 . The lens unit according to claim 1 , wherein the flexible printed circuit board includes a first notch portion adjacent to the protruding portion in a circumferential direction; and the first notch portion is notched toward an inner side in a radial direction.
4 . The lens unit according to claim 3 , wherein the protruding portion includes a first protrusion portion disposed on one side in a circumferential direction of the extension portion and a second protrusion portion disposed on the other side in the circumferential direction of the extension portion; and the first notch portion is provided between the extension portion and the first protrusion portion and between the extension portion and the second protrusion portion.
5 . The lens unit according to claim 4 , wherein the flat surface portion is annular; a connecting portion connecting to the extension portion is provided on a part in a circumferential direction of the flat surface portion; and the flexible printed circuit board includes a second notch portion having an inner peripheral edge of the connecting portion notched to the outer side in the radial direction.
6 . The lens unit according to claim 5 , wherein the first notch portion and the second notch portion are adhesive application grooves.
7 . The lens unit according to claim 1 , wherein the flexible printed circuit board includes a heater disposed on the flat surface portion.
8 . The lens unit according to claim 2 , wherein the flexible printed circuit board includes a first notch portion adjacent to the protruding portion in a circumferential direction; and the first notch portion is notched toward an inner side in a radial direction.
9 . The lens unit according to claim 8 , wherein the protruding portion includes a first protrusion portion disposed on one side in a circumferential direction of the extension portion and a second protrusion portion disposed on the other side in the circumferential direction of the extension portion; and the first notch portion is provided between the extension portion and the first protrusion portion and between the extension portion and the second protrusion portion.
10 . The lens unit according to claim 9 , wherein the flat surface portion is annular; a connecting portion connecting to the extension portion is provided on a part in a circumferential direction of the flat surface portion; and the flexible printed circuit board includes a second notch portion having an inner peripheral edge of the connecting portion notched toward the outer side in the radial direction.
11 . The lens unit according to claim 10 , wherein the first notch portion and the second notch portion are adhesive application grooves.
12 . The lens unit according to claim 1 , wherein the flat surface portion of the flexible printed circuit board and the regulation portion of the first housing portion of the lens holder are not in contact with each other.