US-12619047-B2 - Lens unit

US12619047B2US 12619047 B2US12619047 B2US 12619047B2US-12619047-B2

Abstract

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.

Inventors

Yasuo Tsuruoka
Akinori Yamamoto
Katsumi Umeda
Masanori TANIKAWA
Shinya Okada

Assignees

NIDEC SANKYO CORPORATION
PANASONIC CORPORATION

Dates

Publication Date: 20260505
Application Date: 20210714
Priority Date: 20200715

Claims (12)

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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefits of Japanese Patent Application No. 2020-121287 filed Jul. 15, 2020. The content of Japanese Patent Application No. 2020-121287 is hereby incorporated by reference in its entirety. BACKGROUND Field of the Invention At least an embodiment of the present invention relates to a lens unit in which a plurality of lenses are disposed on an optical axis. Description of the Related Documents Japanese Patent No. 4252959 and Japanese Unexamined Patent Application Publication No. 2019-168509 disclose a lens unit used in an optical device. The lens unit of Japanese Patent No. 4252959 includes a plurality of lenses disposed on an optical axis and a lens holder that holds the plurality of lenses. The lens holder has a lens barrel (support means) and a case (casing) that covers the lens barrel. Moreover, a similar lens unit is disclosed also in Japanese Unexamined Patent Application Publication No. 2019-168509. In the lens unit of Japanese Patent No. 4252959 and Japanese Unexamined Patent Application Publication No. 2019-168509, a heater is disposed inside the lens unit in order to suppress condensation inside the lens unit when the lens unit is used outdoors. For example, Japanese Patent No. 4252959 describes the use of a conductive film such as an ITO film formed on the lens surface as a heater. In addition, Japanese Unexamined Patent Application Publication No. 2019-168509 describes a flexible printed circuit board with an electric heating wire (heater) disposed between a first lens and a second lens. In a lens unit including a plurality of lenses, positioning of the lenses in the optical axis direction is performed by bringing an outer peripheral portion of the lens into contact with the other lenses or a lens barrel in the optical axis direction. Here, Japanese Patent No. 4252959 describes that, when the ITO film is used as a heater, power is fed by using an extraction electrode disposed on an outer peripheral portion of the ITO film and a wiring member (connection line) connected to the extraction electrode, but if the connection portion between the extraction electrode and the wiring member is sandwiched between the lens and the lens barrel or another lens, the connection portion is pressed, and the wiring member and the electrode are crushed. This may cause nonconformities such as a short circuit. For example, in Japanese Unexamined Patent Application Publication No. 2019-168509, a flexible printed circuit board is used as a wiring member. When the flexible printed circuit board is used as a wiring member for feeding power to the ITO film, if the connection portion between the extraction electrode of the ITO film and the flexible printed circuit board is sandwiched between the lens and the lens barrel or another lens, the connection portion will be crushed, which causes a short circuit. For example, if a fine wiring pattern made of a conductive material is formed on a flexible printed circuit board, there is a risk that the wiring pattern is crushed, and a short-circuit occurs between the wirings. In view of the above-described problems, a problem of at least an embodiment of the present invention is to avoid the occurrence of nonconformities such as a short circuit caused by a crush of a connection portion between an electrode for feeding power to a conductive film (heater) disposed on the surface of a lens and an electrode on a flexible printed circuit board. SUMMARY In order to solve the above problem, the lens unit of at least an embodiment of the present invention has a first lens disposed 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 conductive film disposed on an image-side surface of the first lens, and a flexible printed circuit board that feeds power to the conductive film, in which the image side surface includes an image-side lens surface and an image-side flange surface that surrounds the image-side lens surface, the flexible printed circuit board includes a flat surface portion along the image-side flange surface, an extension portion extending to an outer side in a radial direction, and a protruding portion that projects to the outer side in the radial direction from the flat surface portion, and the protruding portion includes an electrode electrically connected to the conductive film. According to at least an embodiment of the present invention, since the first lens can be heated by the conductive film, condensation inside the lens unit which causes lowering the optical performance can be suppressed. In addition, in the flexible printed circuit board that feeds power to the conductive film, electrodes for connection to the conductive film are disposed on the protruding portion that projects to the outer side in the radial