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JP-2026075253-A - Lens module and imaging device

JP2026075253AJP 2026075253 AJP2026075253 AJP 2026075253AJP-2026075253-A

Abstract

[Problem] To provide a technology for reducing changes in the tilt of the lens barrel in a screw-in type lens module with a simple configuration. [Solution] The lens module comprises a lens barrel having a threaded portion on its outer circumferential surface for holding a lens, a lens holder having a threaded portion on its inner circumferential surface that engages with the threaded portion of the lens barrel and holding the lens barrel so that it can move back and forth in the optical axis direction of the lens, and a circular biasing member disposed between the outer circumferential surface of the lens barrel and the inner circumferential surface of the lens holder, wherein the biasing member is formed such that at least a portion of the cross-sectional area on the plane including the optical axis of the lens is different in order to give different biasing forces. [Selection Diagram] Figure 3

Inventors

  • 吉田 雅未

Assignees

  • キヤノン株式会社

Dates

Publication Date
20260508
Application Date
20241022

Claims (9)

  1. A lens barrel having a threaded portion on its outer surface and holding a lens, A lens holder having a threaded portion on its inner circumferential surface that engages with the threaded portion of the lens barrel, and holding the lens barrel so that it can move back and forth in the optical axis direction of the lens, A circular biasing member is disposed between the outer circumferential surface of the lens barrel and the inner circumferential surface of the lens holder, The lens module is characterized in that the biasing member is formed such that at least a portion of the cross-sectional area in the plane including the optical axis of the lens is different in order to give different biasing forces.
  2. The biasing member has a first portion and a second portion located opposite the first portion. The lens module according to claim 1, characterized in that the cross-sectional area of the first portion in the plane including the optical axis of the lens and the cross-sectional area of the second portion in the plane including the optical axis of the lens are different.
  3. The lens module according to claim 1, characterized in that, when the coefficient of friction between the lens barrel and the biasing member is μb, and the coefficient of friction between the lens holder and the biasing member is μh, μb < μh.
  4. The lens module according to claim 1, characterized in that, when the contact area between the lens barrel and the biasing member is Sb, and the contact area between the lens holder and the biasing member is Sh, Sb < Sh.
  5. The lens module according to claim 1, characterized in that the biasing member has a rotation-preventing portion for the lens barrel extending in the circumferential direction.
  6. The lens module according to claim 1, characterized in that the biasing member seals the gap between the lens barrel and the lens holder.
  7. The lens module according to claim 1, characterized in that the contact surface of the biasing member with the lens holder has a shape that is smoothly continuous in the direction perpendicular to the optical axis.
  8. The lens module according to claim 2, characterized in that, if Wc is the height of the first portion of the biasing member before deformation in the direction perpendicular to the optical axis, and Wd is the height of the second portion, which has a smaller cross-sectional area than the first portion, in the direction perpendicular to the optical axis, then Wd ≤ Wc ≤ Wd × 23/15.
  9. An imaging apparatus comprising an image sensor and a lens module according to any one of claims 1 to 8.

Description

This invention relates to a lens module and an imaging device equipped with a lens module. A screw-in lens module is known that allows for focus adjustment by rotating the lens barrel, which holds the lens, thereby moving the lens barrel forward and backward in the optical axis direction. In a screw-in lens module, threads are formed on both the lens barrel and the lens holder to which the lens barrel is attached. The lens holder and lens barrel are screwed together via the threads, and rotating the lens barrel causes the lens barrel to move relative to the lens holder in the optical axis direction. Furthermore, in screw-in lens modules, play occurs between the threaded portion of the lens barrel and the threaded portion of the lens holder due to tolerances and manufacturing errors. This play can cause the lens barrel to tilt relative to the lens holder, potentially leading to tilting relative to the image sensor. Especially in screw-in lens modules, the lens barrel moves each time it is rotated for focusing, causing a change in its tilt. When the lens barrel's tilt changes, adjusting the image sensor's tilt to match the lens barrel's tilt becomes time-consuming. Patent Document 1 discloses a technique in which a portion of the lens barrel has an elastically deformable extension, and when the lens barrel and lens holder are screwed together, the extension contacts the lens holder and the elastic deformation reaction force suppresses play between the lens barrel and lens holder. Japanese Patent Publication No. 2023-74047 Overall view of the camera module equipped with the lens module of Embodiment 1Exploded perspective view of a camera module equipped with the lens module of Embodiment 1.Cross-sectional view of a camera module equipped with the lens module of Embodiment 1Exploded perspective view of the lens barrel and elastic member of Embodiment 2Enlarged cross-sectional view of the elastic member of the lens module in Embodiment 3 Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. <Example 1> The lens module in Embodiment 1 will now be described with reference to Figures 1 to 4. Figure 1 is an overall view of the camera module equipped with the lens module of Embodiment 1. Figure 2 is an exploded perspective view of the camera module equipped with the lens module of Embodiment 1. The camera module 1 consists of a lens module 4 and an imaging unit 5 fixed to the lens module 4. The lens module 4 consists of a lens barrel 10, a lens holder 20, and a biasing member 30. The lens barrel 10 holds a lens group 100, which includes at least one lens. The lens barrel 10 is detachable (replaceable) from the lens holder 20. Therefore, to change the focal length, the lens barrel 10 is replaced. The lens holder 20 holds the lens barrel 10 so that it can move back and forth in the optical axis direction of the lens. The biasing member 30 is a member that biases the lens barrel 10. The biasing member 30 seals the gap between the lens holder 20 and the lens barrel 10. The imaging unit 5 consists of an image sensor 60 and an imaging substrate 70. The image sensor 60 is a CMOS sensor or CCD sensor, which converts the optical image (subject image) formed by the imaging optical system into an analog electrical signal (imaging signal). The image sensor 60 is mounted on the imaging substrate 70. The imaging substrate 70 is fixed to the lens holder 20 with screws 80. Note that the method of fixing the imaging substrate 70 and the lens holder 20 may be by other means, such as adhesive fixing. Alternatively, the imaging substrate 70 may be fixed to a plate member, and the imaging substrate 70 may be fixed to the lens holder 20 via the plate member. Furthermore, a sealing member may be placed between the imaging substrate 70 and the lens holder 20 to prevent dust from adhering to the image sensor 60. Next, the lens module 4 will be described in detail using Figure 3. Figure 3(a) is a cross-sectional view of the lens module of Embodiment 1 before the biasing member 30 is placed between the lens barrel 10 and the lens holder 20 (before deformation). Figure 3(b) is a cross-sectional view of the lens module of Embodiment 1 after the biasing member 30 is placed between the lens barrel 10 and the lens holder 20 (after deformation). Note that although Figure 3(a) shows the lens module before the biasing member 30 is placed between the lens barrel 10 and the lens holder 20, other components such as the lens barrel 10 are also shown for clarity. Therefore, the biasing member 30 appears to overlap with the lens barrel 10 in this diagram. The lens barrel 10 has a cylindrical portion 11 on its outer surface, and a male threaded portion 12 is formed on a part of the cylindrical portion 11. The material of the lens barrel 10 is a metal such as aluminum or a resin such as polycarbonate. The lens holder 20 has a cylindrical tube portion 21 on its inner circumferential surfac