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Method for grounding a temperature-sensitive liquid crystal microdisplay to a substrate using solder ball laser shooter technology

IP.com Disclosure Number: IPCOM000083143D
Publication Date: 2005-Mar-01
Document File: 4 page(s) / 217K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for grounding a temperature-sensitive liquid crystal microdisplay to a substrate using solder ball laser shooter technology. Benefits include improved functionality, improved performance, improved ease of manufacturing, and improved process simplicity.

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Method for grounding a temperature-sensitive liquid crystal microdisplay to a substrate using solder ball laser shooter technology

Disclosed is a method for grounding a temperature-sensitive liquid crystal microdisplay to a substrate using solder ball laser shooter technology. Benefits include improved functionality, improved performance, improved ease of manufacturing, and improved process simplicity.

Background

      The application of a cross-over ground connection on a microdisplay device from the cover glass to the substrate is an extremely difficult task to complete in high volume. It is either time consuming or costly to the process flow.

              Conventionally, the cross-over ground is applied by hand soldering the connection. An alternative method is the manual dispensing by an operator of a conductive epoxy bead between the display glass and the substrate. To make the indium tin oxide (ITO) and conductive epoxy connection robust, the interface is treated with a laser after thermal curing. This treatment is a very delicate process that relies on manual precision. No material can remain on top of the cover glass. Other methods, such as conductive metal clips or pins, are also possible alternatives to hand soldering but are too costly.

              The conventional manual ground connection process occurs after cell attach to the mesa. The operator manually dispenses the conductive epoxy bead in between the display glass and the shim. The substrate must be rotated (see Figure 1).

              The assembly is cured in an oven for 2 hours at 60°C to cure the die attachment and the ITO at the same time. Afterwards, a laser is used to make the connection more robust.

General description

      The disclosed method is a ground connection from the glass cover plate ITO to the ceramic substrate by using solder ball shooter technology.

              The key elements of the disclosed method...