Glass cap wirebond protection for imaging tiles in an x or gamma ray indirect imaging detector

Abstract

Wirebond protection is provided for imaging tiles in which the imaging sensor and PCB are mounted side-by-side on a tile carrier for use in X or Gamma Ray indirect imaging detectors without use of a “glob top” encapsulant. A glass cap comprising a bead of adhesive material and a lid is formed to provide an enclosed open-air cavity around the wire bonds. As such, any expansion of the bead material does not produce mechanical stress on the wire bonds.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention relates to X or Gamma ray indirect imaging detectors and more specifically to wirebond protection without use of an encapsulant.[0003]2. Description of the Related Art[0004]X or Gamma ray indirect imaging detectors include a conversion layer or “scintillator” that converts X or Gamma rays to visible light, an optional fiber optic plate (FOP) that transfers light to an imaging plane and a visible band imaging sensor at the imaging plane. For X rays, phosphor or cesium-iodide are typical conversion layer materials. The FOP protects the imaging detector from being damaged by the high energy X or Gamma rays, prevents the sensor from reading those rays as light and takes the image created by the conversion layer and focuses it on the imaging sensor keeping the image sharp and coherent. Indirect imaging leverages the established visible band CCD and CMOS imaging technologies.[0005]To read out the image, the ima...

AI Technical Summary

Benefits of technology

The patent describes a tile that includes an imaging sensor and a PCB mounted side-by-side on a common carrier. The imaging sensor uses wire bonds to connect to the PCB. An adhesive material is applied to the top surface of the imaging sensor and the carrier, forming a continuous perimeter around the wire bonds and the imaging area. A lid is placed on the adhesive material to form an enclosed cavity around the wire bonds. The adhesive material may be UV cured or visible light, thermal, or moisture curable. The lid may also be made of a transparent material to allow inspection of the wire bonds. A second bead of material may be applied around the perimeter of the lid to make the enclosure air tight to protect the wire bond from environmental effects. The technical effect of this design is a more durable and reliable imaging sensor that can withstand environmental stresses.

Problems solved by technology

The wire bonds are very fragile and susceptible to damage or failure due to corrosion or mechanical stress that may occur during final assembly and handling.

The failure of even a single wire bond can result in the loss of the detector.

Images