Image sensor containment system

• US 5,838,495 A
• Filed: 03/25/1996
• Issued: 11/17/1998
• Est. Priority Date: 03/25/1996
• Status: Expired due to Term

• Current Assignee: Welch Allyn Incorporated
• Original Assignee: Welch Allyn Incorporated
• Inventors: Hennick, Robert J.
• Primary Examiner(s): Nguyen, Thong
• Assistant Examiner(s): Robinson, Mark A.
• Application Number:
  US08/620,909
• Time in Patent Office: 967 Days
• Field of Search: 359/507, 359/513, 359/514
• US Class Current: 359/507
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10841 Particularities of the light-sensitive elements semiconductor devices H01L
• CPC Class Codes: H04N 1/00909 Cleaning arrangements or preventing or counter-acting contamination from dust or the like cleaning in general, prevention of fouling in general B08B
• CPC Class Codes: H04N 1/028 for picture information pick-up

Abstract

A containment system for containing an image sensor. The containment system includes a substrate for carrying an image sensor, an optics housing disposed about the image sensor and secured to the substrate, and a foam barrier interposed between the housing and the image sensor or between the optics housing and the substrate. The foam barrier of the containment system prevents the intrusion of particulate and stray light rays into the containment interior. Further, the foam barrier traps particulate so as to inhibit the free circulation of particulate in the region surrounding the containment system. Because it allows for a circulation of air into and out of the containment system, the foam barrier encourages the evaporation of condensate which may form on the contained image sensor and/or optical lens components.

Claims

1. In an optical reading apparatus of the type including an integrated circuit image sensor having an array of picture elements, a substrate for supporting said image sensor, an optics housing for protecting said image sensor from ambient light and for supporting a lens assembly in light focusing relationship to said array, and means for securing said image sensor and said optics housing to said substrate, at least two of said image sensor, said optics housing and said substrate together defining an opening through which air may circulate between the atmosphere and the interior of said optics housing, the improvement comprising:

a compressible barrier member which, when disposed in said opening, defines a multiplicity of pores having sizes which allow substantially particulate-free air to circulate between said interior and the atmosphere, but which filters out and traps particulates suspended in said air.

2. A reading apparatus as set forth in claim 1 in which said image sensor has an upper surface, and in which said barrier member is disposed between said upper surface and said optics housing and makes contact with said upper surface along the entire periphery thereof.

3. A reading apparatus as set forth in claim 1 in which said optics housing has a lower surface, and in which said barrier member is disposed between said lower surface and said substrate and makes contact with said lower surface along the entire periphery thereof.

4. A reading apparatus as set forth in claim 1 in which said image sensor has a generally horizontally disposed upper surface and at least one generally vertically disposed side surface, and in which said barrier member is disposed between said optics housing and said upper and said at least one side surface of said image sensor.

5. A reading apparatus as set forth in claim 2 in which said horizontally disposed upper surface and said at least one vertically disposed side surface define a step that extends around the entire periphery of said image-sensor, and in which said barrier member makes contact with said step along the entire periphery thereof.

6. A reading apparatus as set forth in claim 1 wherein said compressible barrier member comprises a foam material.

7. A reading apparatus as set forth in claim 6 in which said foam material has a density less than about 5 lb/ft³.

8. A reading apparatus as set forth in claim 6 in which said foam material has a density less than about 2 lb/ft³.

9. A reading apparatus as set forth in claim 6 in which said foam material comprises polyester-polyurethane.

10. A reading apparatus as set forth in claim 6 in which said barrier member comprises a piece of open cell polyester-polyurethane foam having a density of about 2 lb/ft³.