Optical: systems and elements – Lens – With support
Reexamination Certificate
1999-12-15
2001-05-15
Epps, Georgia (Department: 2873)
Optical: systems and elements
Lens
With support
C359S821000, C359S808000
Reexamination Certificate
active
06233103
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved housing structure for fixedly holding a lens array for use in an optical reader or the like.
2. Description of the Related Art
In recent years, optical readers employ an element called a rod lens array. An example arrangement of such a rod lens array is disclosed in, for example, Japanese Patent Laid-Open Publication No. HEI-8-220645 entitled “STRUCTURE FOR FIXEDLY HOLDING A ROD LENS ARRAY FOR USE IN OPTICAL READER”. The disclosed rod lens array comprises a plurality of columnar distributed index lenses made from a transparent material such as glass and plastics, arranged side by side in a row and then fixed by means of a resin. Thus, the array is elongate and has a rectangular cross section. In use, the array is held in a holder or a housing.
More specifically, the rod lens array is fitted in a U-shaped recess or groove formed in the holder and fixedly held therein by filling a space between a right wall defining part of the groove and a right wall of the lens array with a silicone resin and filling a space between a left wall of the groove and a left wall of the lens array with an acrylic resin.
Due to its flexibility, silicone resin is often used in this field of technology. However, it requires at least 30 minutes for the resin to become hardened. When complete hardening or setting needs to be assured, the resin should be allowed about 60 minutes to harden. During hardening of the resin, the rod lens array must be held immovably by means of an appropriate jig or clamp. This operation is tedious and time consuming, thereby making it difficult to achieve the desired increase in productivity.
To this end, there has been proposed as an adhesive a silicone-based resin which becomes hardened by ultraviolet rays in a shortened period of time. However, the proposed resin not only is expensive but also requires installations for producing unltraviolet rays, thereby increasing the cost of production of the end product.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a housing structure to which a rod lens array can be fixedly secured quickly.
According to an aspect of the present invention, there is provided a housing structure for fixedly holding an elongate lens array of rectangular cross section, which housing structure comprises an elongate U-shaped groove extending along the length of the housing structure and having a width and a depth corresponding to a sectional height and width of the lens array so that the lens array can be fitted therein, and at least one protrusion of thermoplastic resin provided at an open edge extending along the groove to thereby partly define the groove. The protrusion is thermally deformed to radially spread over part of the lens array so that the lens array can be fixedly held in the groove.
With this arrangement, it is no longer necessary to keep holding the lens array until an adhesive solidifies as required in the conventional arrangement. Consequently, after a short period of time for deforming the protrusion, the housing structure with the lens array fixedly housed therein can be passed to a succeeding process, thereby increasing the productivity.
Desirably, the protrusion comprises two protrusions of thermoplastic resin provided at opposite ends of the open edge.
The housing structure may be wholly made of a thermoplastic resin.
The lens array may comprise a rod lens array having a plurality of columnar distributed index lenses arranged side by side in a row and integrally fixed by means of a resin.
In a preferred form, the spread-over part of the protrusion is obtained by heating, press smashing and air cooling it by using a resin welder.
Preferably, the housing structure further comprises at least one cutout provided in the open edge for allowing access to a corner where a side surface of the lens array and a bottom surface of the cutout meet, and an adhesive applied to the corner for connecting together the lens array and the cutout bottom surface. The adhesive adds up the firmness of connection of the lens array to the housing structure, thereby increasing the reliability of the latter.
The adhesive may comprise a silicone-based adhesive.
It is desirable that the adhesive is applied by means of an adhesive gun accessed through the cutout.
The adhesive may be oval or semi-circular in shape when applied.
REFERENCES:
patent: 4059345 (1977-11-01), Kawamura et al.
patent: 4961802 (1990-10-01), Otsuki et al.
patent: 362171374 (1987-07-01), None
patent: 363080669 (1988-04-01), None
patent: 404261506 (1992-12-01), None
patent: 8-220645 (1996-08-01), None
patent: 409238227 (1997-09-01), None
Epps Georgia
Merchant & Gould P.C.
Nippon Sheet Glass Co. Ltd.
Seyrafi Saeed
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