Optical: systems and elements – Lens – With support
Reexamination Certificate
1999-01-07
2001-04-10
Epps, Georgia (Department: 2873)
Optical: systems and elements
Lens
With support
C359S704000, C359S822000
Reexamination Certificate
active
06215603
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based on Application No. HEI 10-1211 filed in Japan filed on Jan. 7, 1998, the content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lens holding structure, and more specifically relates to a lens holding structure in a lens block of an optical system used in optical devices such as a digital camera, video camera, lens shutter camera and the like.
2. Description of the Related Art
Recent years has seen a demand for compact digital still cameras, lens shutter cameras and the like, and particularly heightened demand for compactness in optical systems that occupy a relatively large space in such equipment. Size of an optical system in a direction of an optical axis thereof, i.e., a distance from a surface of a lens positioned on the outermost object side to the image plane is determined by the optical design specifications and the like. On the other hand, a size of the optical system in a direction perpendicular to the optical axis is normally determined by an outer diameter of a lens element forming a structural element of the optical system. The size of the optical system is determined based on a lens element of the largest outer diameter since each lens element is held by fixedly fitting the outer circumference of the lens element within a holding barrel. Accordingly, in a conventional optical system, the holding barrel cannot be made smaller than the lens element of the largest outer diameter even when there are markedly different outer diameters among the lens elements, thereby disadvantageously enlarging the optical system.
In order to eliminate this disadvantage, U.S. Pat. No. 5,699,200 proposes a lens holding structure that reduces the outer diameter of the holding barrel by providing a notch in the outer circumference of the lens element and securing the lens element by applying an adhesive to the notch. U.S. Pat. No. 5,461,444 proposes a lens holding structure wherein flat surface areas parallel to the optical axis are formed outside effective diameter of a lens element with the lens element fastened to the holding barrel via screws in the flat surface areas.
In the lens holding structure disclosed in U.S. Pat. No. 5,699,200, however, it is difficult to reduce the cost of the lens element due to the complex shape of the lens element provided with the notch, and the notch cannot always be formed depending on the shape of the lens element. Furthermore, in the lens holding structure disclosed in U.S. Pat. No. 5,461,444, sufficient compactness cannot be attained because holding areas formed on the holding barrel for the screw fastening in the flat surface areas have a larger diameter than the largest outer diameter of the lens element.
OBJECT AND SUMMARY
An object of the present invention is to provide an improved lens holding structure and lens block assembling method, capable of eliminating the previously described disadvantages.
Another object of the present invention is to provide a lens holding structure and a lens block assembling method capable of attaining a compact lens block of inexpensive and simple construction.
These objects are attained by providing a lens holding structure in a lens block forming all or part of an optical system, the lens holding structure comprising:
a first lens element;
a second lens element arranged adjacent to the first lens element with a predetermined open space on an optical axis of the lens block relative to the first lens element; and
a holding barrel having an outer diameter smaller than the maximum outer diameter of the first lens element;
wherein the second lens element is fixed to the holding barrel, and the first lens element is directly attached and fixed only to the second lens element.
In this lens holding structure, the first lens element may be fixed to the second lens element by adhesive. Furthermore, the first lens element may include a first face perpendicular to the optical axis and outside effective diameter thereof, and the second lens element may include a second face perpendicular to the optical axis and outside effective diameter thereof, and the first lens element may be fixed to the second lens element by adhering the first face to the second face using adhesive.
These objects are further attained by providing a lens holding structure in a lens block forming all or part of an optical system, the lens holding structure comprising:
a first lens element; and
a holding barrel having an outer diameter smaller than the maximum outer diameter of the first lens element;
wherein the first lens element is directly attached and fixed to the holding barrel only by a first face thereof perpendicular to an optical axis of the lens block.
In this lens holding structure, the first lens element may be fixed to the holding barrel by adhesive. The holding barrel may include a second face perpendicular to the optical axis, and the first lens element may be fixed to the holding barrel by adhering the first face to the second face using adhesive. Furthermore, the lens holding structure may be further provided with the second lens element arranged adjacent to the first lens element with a predetermined open space on the optical axis relative to the first lens element.
These objects are further attained by providing a lens holding structure in a lens block forming all or part of an optical system, the lens holding structure comprising:
a first lens element; and
a holding barrel having an outer diameter smaller than the maximum outer diameter of the first lens element;
wherein the first lens element is directly attached and fixed to the holding barrel by a first face thereof placed at an angle with respect to an optical axis of the lens block.
In this lens holding structure, the first lens element may be fixed to the holding barrel using adhesive. Furthermore, the holding barrel may include a second face corresponding to the first face of the first lens element, and the first lens element may be fixed to the holding barrel by adhering the first face to the second face using adhesive. The lens holding structure may be further provided with the second lens element arranged adjacent to the first lens element with a predetermined open space on the optical axis relative to the first lens element.
These objects are attained by providing a lens holding structure in a lens block forming all or part of an optical system, the lens holding structure comprising:
a first lens element; and
a holding barrel having an outer diameter smaller than the maximum outer diameter of the first lens element;
wherein the first lens element directly attached and fixed to the holding barrel by a first face outside effective diameter thereof, the first face forming an extension of effective surface of the first lens element.
In this lens holding structure, the first lens element may be fixed to the holding barrel using adhesive. The holding barrel may include a second face corresponding to the first face of the first lens element, and the first lens element may be fixed to the holding barrel by adhering the first face to the second face using adhesive. The lens holding structure may be further provided with the second lens element arranged adjacent to the first lens element with a predetermined open space on the optical axis relative to the first lens element.
These objects are further attained by providing a method for assembling the lens block which forms all or part of an optical system and includes a first lens element, a second lens element adjacent to the first lens element and a holding barrel having an outer diameter smaller than the maximum outer diameter of the first lens element, the method comprising the steps of:
fixing the second lens element to the holding barrel;
adhering the first lens element to the second lens element or the holding barrel using adhesive; and
centering the first lens element before adhesion at the step of adhering is completely finished, so as to achieve alignment of the lens block.
Doi Tomoo
Ishimaru Kazuhiko
Isono Masashi
Kohno Tetsuo
Mukai Hiromu
Epps Georgia
Minolta Co. , Ltd.
Morrison & Foerster / LLP
Thompson Tim
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