Optical unit and endoscope provided with optical unit

Abstract

An optical unit (1) is provided with: a lens retaining frame (11) for retaining an objective optical system (13); an imaging element retaining frame (12) for retaining an imaging element (21) having a light-receiving part (21a) for detecting a subject image formed by the objective optical system (13), a first retaining frame being inserted and fitted in the imaging element retaining frame (12); a weld part (30) provided to a fitting part of the lens retaining frame (11) and the imaging element retaining frame (12), the weld part (30) for fixing the lens retaining frame (11) and the imaging element retaining frame (12) in a fitting position in which the light-receiving part (21a) and the image plane of the subject image from the objective optical system (13) coincide; and a joining material (31) for filling a gap formed between the lens retaining frame (11) and the imaging element retaining frame (12).

Description

technical field [0001] The present invention relates to an optical unit for an endoscope. The optical unit fits and fixes a lens frame and an element frame. Background technique [0002] In order to observe difficult-to-observe parts such as the inside of a living body or the inside of a structure, an endoscope that can be introduced into the inside from the outside of the living body or structure is used, for example, in the medical field or in the industrial field. Optical units such as camera units. [0003] An optical unit such as an imaging unit of an endoscope has: an objective lens that forms an image of a subject; at the imaging surface. [0004] Such an optical unit is known, for example, as an imaging unit disclosed in Japanese Patent Application Laid-Open No. 2002-238837. Usually, the lens frame and the element frame are fitted together, and then joined by soldering with a thermosetting adhesive or solder. The material is bonded and fixed. [0005] However, in...

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Problems solved by technology

[0005] However, in the conventional optical unit, there is a problem that when the lens frame and the element frame are fitted and fixed so that the focal position of the lens coincides with the light-receiving part of the imaging element, a problem occurs during the curing process of the bonding material. Due to the expansion and contraction of the lens frame and the element frame including the bonding material, the predetermined fitting position of the lens frame and the element frame is fixed so that the desired optical performance cannot be obtained.

[0007] In endoscopes in recent years, the increase in the number of pixels of captured endoscope images and the reduction in the diameter of the insertion part to improve insertion performance have been advanced. The device may use a small device, so the following problem has arisen: even if the deviation of the fitting position of the lens frame and the element frame is small, the appropriate quality of the optical performance cannot be satisfied or the optical performance will be deteriorated.

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