Different axis of work have been developed and compared:
- Chip-on-flex technology, where LCD driver chips are mounted and glob topped directly onto a flex print connected to the lines and the columns of the display, using an anisotropic conductive adhesive (ACA),
- Chip-on-glass technology, where the driver chips are reported directly onto the display substrates, using different mounting techniques:
TAB chips with ACAs,
Resin encapsulated naked chips wire bonded on the glass.
To achieve these objectives, different tasks have been performed:
- Definition of functional specifications of high density ACAs (Z conductors),
- Evaluation of existing ACAs commercially available on the market (US and Japanese suppliers),
- Development of specific ACAs with respect to the defined specifications,
- Development of a bonding technique for high density flex print on glass using ACAs,
- Development of wire bonding on flex-print and encapsulation of naked chips on flex-print,
- Development of a low cost industrial path for low and medium quantity TAB needs or for prototyping,
- Mounting of TAB chips onto an ITO pattern (glass substrate) using ACAs,
- Optimisation of wire bonding on glass and study of compatible finishing metallizations of the glass substrate for this purpose,
- Reliability study of the different techniques.
At the end of this project, the participating industries are able to produce or incorporate high resolution and/or high reliability flat panel displays into their products. The use of these techniques is crucial for European industries to compete with Japan on the market of Flat Panel displays.
Other industries, such as manufacturers of automotive parts, will benefit from this, because they will be able to develop products or equipments containing flat panel displays without having to rely solely on foreign suppliers.
The development of techniques for reliable high density interconnection of plat panel displays is proposed. The developed technologies can be used by display manufacturers as by OEMs. The presently used techniques for the interconnection of liquid crystal displays do not allow the interconnection of high resolution displays. The techniques to be developed in this project will solve the resolution and reliability problems of the presently used ones. Instead of elastomeric connectors to connect the display and the driver-circuits a number of alternatives will be developed:
1. A "chip on Flex-print" technology. A flex-print is connected to the lines and columns of the display by using an anisotropic conducting adhesive. The driver ICs are naked chips mounted onto the flex-print by wire-bonding and these ICs are hermetically sealed afterwards.
2. A "chip On Glass" technology. The driver ICs are mounted directly onto the display-substrate; the glass substrate is used as the "driver PCB" . Different mounting methods of the drivers will be investigated.
a) TAB chips mounted with anisotropic conducting adhesives
b) NAKED chips mounted with wire-bonding onto the display glass substrate.
By the end of this project the participating industries should be able to produce or incorporate high resolution and/or high reliability flat panel displays into their products. The use of these techniques for the interconnection of flat panel displays will be crucial for European industries to compete with Japan on the display market.
Funding SchemeCSC - Cost-sharing contracts
47151 Boecillo - Valladolid