Browse Prior Art Database

Sequential Refresh of Electrochromic Matrix Displays

IP.com Disclosure Number: IPCOM000039316D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Barclay, DJ: AUTHOR [+4]

Abstract

An earlier article [*] proposes that the display image is refreshed progressively on a non-sequential or random basis. This disclosure describes two sequential refresh methods using the hardware shown in the above reference. Firstly, blocks are erased sequentially in multiple areas, and secondly, a venetian blind technique of erasing every nth line, stepping by one line and repeating. There is evidence that bulk erase deterioration is primarily due to absorption of aggregated viologen species on the pel (picture element) surface. As displays are cycled, these aggregated species preferentially accumulate on frequently written pels, and because of the various resistive and electrochemical contributions to the erase process, they have a much more significant impact on bulk erase than on character erase.

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Sequential Refresh of Electrochromic Matrix Displays

An earlier article [*] proposes that the display image is refreshed progressively on a non-sequential or random basis. This disclosure describes two sequential refresh methods using the hardware shown in the above reference. Firstly, blocks are erased sequentially in multiple areas, and secondly, a venetian blind technique of erasing every nth line, stepping by one line and repeating. There is evidence that bulk erase deterioration is primarily due to absorption of aggregated viologen species on the pel (picture element) surface. As displays are cycled, these aggregated species preferentially accumulate on frequently written pels, and because of the various resistive and electrochemical contributions to the erase process, they have a much more significant impact on bulk erase than on character erase. The situation can be significantly improved if the way in which a full screen erase is performed in blocks. From an electrochemical viewpoint the ideal would be a row-by-row erase. This would take rather too long, say, at 30 seconds. However, intermediate cases would help the situation. For example, by erasing the display sequentially in 10 blocks of 30 rows, the time for a full screen erase is around 1 second. This can be effected by the sequential selection of numbers of rows and columns of shift registers 11 and 12 shown in Fig. 1 of the referenced article. The method of erasing a whole screen of information to remove all of the data with a single c...