Browse Prior Art Database

Fourfold Increased Resolution or Color DPDT

IP.com Disclosure Number: IPCOM000086541D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 45K

Publishing Venue

IBM

Related People

Wohl, RJ: AUTHOR

Abstract

This deformable plate display tube (DPDT) provides a fourfold increase in resolution for monochrome displays and permits a polychrome display as an alternative.

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Fourfold Increased Resolution or Color DPDT

This deformable plate display tube (DPDT) provides a fourfold increase in resolution for monochrome displays and permits a polychrome display as an alternative.

Fig. 1 shows a plan view of two unit cells of an x-y matrix of such cells, forming the target for a storage display tube. The quatrefoil cell on the left is for increased resolution monochrome displays while the trefoil on the right is for color displays.

The posts 12 for the deformographic membranes 14,15,16 and 17 and 18,19 and 20 are produced by evaporation of, e.g., Al(2)O(3) over the selectively exposed and developed first photoresist 26 (Fig. 2). Fig. 2 shows the situation at the step preceding the configuration of Fig. 1, as would be seen in a cross- section of the latter. Layer Al(2)O(3), which was deposited on the photoresist, has already been removed in Fig. 2.

The second photoresist 28 is then applied, exposed and the indicated structure is developed. In this case, the photoresist forms an interconnected mesh which fills all the openings between deformographic membranes 14-20. Note that the cross-section of the photoresist shows sloping walls 24. This undercut is a natural accompaniment to thick photoresist films. Efforts to avoid undercut are not made. Instead, the undercut is made even more pronounced by underexposing a negative photoresist or overexposing a positive photoresist, or using a positive photoresist and exposing it with a large-area light source.

The purpose of this undercutting is to assure easy access of the photoresist remover to the photoresist, despi...