Filter lens holding mechanism in filter frame

Abstract

The present invention provides a filter holding mechanism which can stick a filter lens to a thin filter frame without deformation and still have a large effective diameter. In the filter holding mechanism, a calking formation unit mounted and inserted into the rear of filter lens front edge frame and clamping the filter lens on the other surface is formed with a cylindrical ring shaped body from a support edge periphery. The cylindrical ring shaped body of the calking formation unit has a length covering the edge of the anti-reflective covering process surface which is processed to be clad in the other surface of the filter lens by covering a chamfered portion contact surface of the filter lens.

Description

technical field [0001] The present invention relates to the improvement of the filter lens holding mechanism in the filter lens frame. [0002] The present invention provides a filter lens holding mechanism in the filter frame, which can make the size of the filter frame in the direction of the optical axis, that is, the thickness of the filter frame, thinner. , to maximize the effective diameter of the filter lens built into the filter frame. Also, the present invention provides a filter frame that does not easily cause vignetting even if it is installed on the front side of a telescope or a wide-angle lens. Furthermore, the present invention provides a riveting processing method that can prevent physical deformation or deformation due to heating on the filter lens when fixing it while the filter lens is built-in and held in the filter lens frame. The state holds various filter lenses within the filter frame. Background technique [0003] In particular, the filter frame ...

AI Technical Summary

Problems solved by technology

[0008] In the fixing method of the filter lens realized by the above-mentioned riveting process, there is the following disadvantage: the annular edge portion arranged on the inner diameter portion of the incident light side of the filter lens frame main body is received by the riveting tongue portion arranged at the rear portion of the filter lens. The shape processing, the outer diameter size of the riveting mold or the outer diameter size of the riveting heating tool when performing riveting processing, so the effective diameter defined by the annular edge of the filter lens is reduced and usually becomes smaller, so that even Deliberately making the main body of the filter frame thin will also cause vignetting due to the reduction in the effective diameter of the filter lens

It is also necessary to solve the following problem: that is, in order to ensure the holding accuracy of the frame, many holding structures that use convex portions at three positions to receive the lens support surface are used. In this case, the deformation of the lens surface will further become serious.

[0023] Therefore, the disadvantage of the invention of the above-mentioned Patent Document 2 is that, in terms of the three positions on the outer periphery of the lens (2), the convex plane part (1b) and the convex riveted part (1c) of the lens frame body (1) When thermal deformation is caused by pressing, the corner of the peripheral portion of the lens (2) inserted into the inner diameter portion (1d) without gaps during the caulking process is pressed by the caulking tongue, and the lens (2) is deformed by the caulking process

In addition, the same phenomenon also occurs in the lens frame main body (1) produced by cutting a metal annular ring such as aluminum or brass, and has the following disadvantages: in the above-mentioned patent document (2) described In the lens frame main body (1) made of synthetic resin, it is a lens frame having a structure in which the lens (2) is fixed by thermal caulking, and the flat caulking part (3a) is used while sinking the caulking mold (3) in a heated state. ) heats the lens (2) that is fixed when it is deformed by pressing, and the heat is directly transferred through the convex flat part (1b), convex riveted part (1c) and inner diameter part (1), so that the lens (2) generates heat out of shape

In addition, the annular cutting groove 71 needs to have a large inner diameter φ2, and the annular cutting groove 71 needs to be formed to have a large width W. The inner diameter of the optical lens front edge frame 69 decreases in the direction of the optical axis C, thereby producing the following disadvantages: that is, in the filter frame main body 51 whose filter aperture φ has been determined, its effective diameter φ3 is significantly reduced, and becomes vignetting The main reason

In this way, the gap from the edge portion of the chamfered abutting surface 80 to the peripheral edge portion of the anti-reflection coating 81a is a portion that has not been processed for the anti-reflection coating, so there is a gap where reflected light passes through without the anti-reflection coating. Gap incidence adversely affects the performance of the filter lens 52

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