Radiant energy – Photocells; circuits and apparatus – Housings
Reexamination Certificate
1999-03-22
2001-09-18
Epps, Georgia (Department: 2873)
Radiant energy
Photocells; circuits and apparatus
Housings
C250S559300, C438S106000, C438S116000
Reexamination Certificate
active
06291818
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a process and apparatus which compensates for manufacturing variations and more specifically to a process which enables production and assembly errors, associated with the active components in a sensor assembly package, to be quickly and easily compensated for.
BACKGROUND OF THE INVENTION
The accuracy of a sensor arrangement is determined by the relationship between its electronic components and the packaging (housing) that locates the active elements of the sensor in space. Under normal circumstances any errors in the packaging of the elements of the assembly will result in an error in the final position of the active sensor elements with respect to the article/object which is to be scanned and/or otherwise subjected to inspection.
In the case a sensor arrangement includes a lens array which is designed to focus an image on a photo responsive device, such as a charge couple device (CCD) or the like type of opto-electric transducer, any error in the setting of the lens array with respect to the transducer, or vice versa, is apt to cause a blurring, distortion or the like, of the image/data which is developed. The problem is further compounded in the instance that a mirror or prism is used to direct the image into the lens array in that any deviations in the angle and disposition of the mirror with respect to the lens array is, of course, apt to induce accuracy problems.
In devices such as image readers and scanners which are used to read information printed on the surface of an article such as a sheet of paper, envelope, etc., accuracy is paramount and any constructional/assembly errors which reduce this accuracy are apt to render the device partially or totally inoperative for its intended purpose.
The active elements, such as the lens array and the opto-electric transducer may be incorporated into a sub-housing or casing which is adapted to be mounted in the interior of a larger device, such as an optical scanner or the like. However, if these active elements are not precisely located within the sub-housing in a manner wherein the combined effect of the various deviations, which occur as a result of manufacturing and/or assembly, does not fall in an acceptable range, then the whole unit will produce unacceptable results. This, of course, results in the rejection of the unit.
In order to reduce/eliminate the number of units which are rejected for the above mentioned reason, it is necessary to tighten the manufacturing tolerances on each of the individual components as well as those pertaining to their assembly, so as to reduce unnecessary expense of rejecting a fully assembled unit. This of course raises the manufacturing costs and reduces productivity.
Circumnavigating these problems is difficult in as much as there is a tendency to use the unit housing as a reference and attempt to locate all of the elements which are disposed therein, in a very precise spatial relationship with respect to the housing and thus produce a unit which can be mounted in a larger device using preformed location features.
U.S. Pat. No. 5,565,674 discloses an example of the above mentioned type of arrangement. As shown in
FIG. 1
, this arrangement includes an optical package
10
having a molded, optically clear body
12
surrounding the central portion of a wing-shaped support
14
. This support has two wing-shaped portions
16
A and
16
B with mounting holes
18
A and
18
B extending therethrough for receiving mounting screws and permitting the optical package
10
to be mounted to the head of an optical CD read/write system. With this arrangement it is clear that if the active elements are, for any reason, not located within a predetermined tolerance with respect to the mounting holes
18
A,
18
B then the package is apt not to come up to specification and to be subject to rejection.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to an optimization technique which attenuates the above problem. More specifically, the technique is such that, after a package or unit is assembled, the package is moved with respect to a target and when a response of a sensor which is included in the package, responds to the target in a predetermined manner, indicating that the active element or elements in the package are suitably located with respect to the target, a location feature or mount is permanently deformed to form a location face. The location face is then used to located the package in a device in a manner wherein, irrespective of the minor deviations within the unit, the unit per se will, after final assembly of the device of which the unit forms a part, be supported in a position wherein acceptable operational characteristics will be derived.
It is an object of the invention to provide a technique whereby one or more location features on the case or unit which houses active elements such as a CCD, to be deformed by swaging or the like, in a manner which will ensure that the casing can be mounted in a device and support the active elements in space in a desired relationship with respect to a target.
In brief, in order to achieve the above objects and to locate a package casing which houses active elements including a sensor, in a position which assures that the sensor and other active elements will be located in a proper operative position when installed in a predetermined piece of apparatus, the package casing is provided with location features and is moved with respect to a target until such time as the sensor is detected as producing an optimal output. Under these conditions, one or more selected location features are deformed using a swaging tool or the like, to form location faces which have a predetermined spatial relationship with the active elements and which ensure that the active elements will be supported in an optimally operative position when the package is mounted in a device such as an optical scanner or the: like.
More specifically, a first aspect of the present invention resides in a method of optimizing comprising the steps of: forming a case with at least one location features, and disposing a sensor, which is provided either alone in combination with a plurality of other active elements, within the case in a predetermined relationship with respect to the case. The case is then selectively moved with respect to a target while the response of the sensor to the target (via, the sensor output) is monitored. When the sensor response meets a predetermined requirement, the movement of the case is halted and a location feature is deformed to form a location face. This face has a predetermined spatial relationship with the active elements within the case and locates the active elements in an optimal operating position when the case is mounted in a predetermined device.
A second aspect of the present invention resides in an optimizing apparatus comprising: means for supporting a case which has one or more location features and in which a sensor, which is either provided alone or in combination with one or more other active elements, is supported in a predetermined relationship therein; means for selectively moving the case with respect to a target; means for monitoring the response of the sensor to the target and for halting the movement of the case when the sensor output (viz., response) meets a predetermined requirement; and means for permanently deforming a selected location feature to form a location face which has a predetermined spatial relationship with sensor and which locates the sensor and/or active elements in a predetermined operative position when the case is mounted in a predetermined device.
REFERENCES:
patent: 4743772 (1988-05-01), Hefele et al.
patent: 5565674 (1996-10-01), Reele
patent: 5801374 (1998-12-01), Cambell et al.
patent: 6096575 (2000-08-01), Okada et al.
Allport Robert W.
Ferrari Graeme
Mitchell Paul
Morgan David
Capelli Christopher J.
Epps Georgia
Melton Michael E.
Pitney Bowes Inc.
Seyrafi Saeed
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