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A Technique to Overcome Pel Limitations on a Plasma Panel

IP.com Disclosure Number: IPCOM000044737D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Haslam, M: AUTHOR [+3]

Abstract

In a plasma panel used for display of alpha-numeric characters, the number of picture elements (pels) operated at any one time in limited due to current limitations during discharge. A technique is necessary to avoid exceeding this limit when an overload condition such as "Reversed" characters are displayed, i.e., where the cells designating the characters are turned "off", while all other background cells which do not define the character are turned "on". The plasma display is generated by horizontal scanning techniques, and the conventional display contains a plurality of rows of characters corresponding to the size of the character matrix.

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A Technique to Overcome Pel Limitations on a Plasma Panel

In a plasma panel used for display of alpha-numeric characters, the number of picture elements (pels) operated at any one time in limited due to current limitations during discharge. A technique is necessary to avoid exceeding this limit when an overload condition such as "Reversed" characters are displayed,
i.e., where the cells designating the characters are turned "off", while all other background cells which do not define the character are turned "on". The plasma display is generated by horizontal scanning techniques, and the conventional display contains a plurality of rows of characters corresponding to the size of the character matrix.

To solve the inversion problem, all pels in the bottom line of each character row are turned off, and the adjacent rows are sequentially erased until the total number of lighted pels is within the limit of the display. This is effective since the rows at the bottom of the character display are primarily designed to contain cursors and underscores and thus generally unused. Thus, even in extreme cases, a large number of pels can be turned off before degrading the characters being displayed.

In the example illustrated in the accompanying drawing, 148 of 192 pels are lighted. Suppose the display limit is 50%, i.e. 96 pels. By turning off the pels in the bottom 4 rows of the character cells, only 88 pels will remain lighted, while the display characters themselves are sub...