Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1999-02-17
2001-11-13
Sikes, William L. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S139000
Reexamination Certificate
active
06317184
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to liquid crystal displays (LCDs), and more specifically to an LCD with enhanced character visibility.
The LCD of the present invention has particular application in electronic price labels. EPL systems typically include a plurality of EPLs for merchandise items in a transaction establishment. EPLs typically display the prices of corresponding merchandise items on store shelves and are typically attached to a rail along the leading edge of the shelves. The EPLS are coupled to a central server from where information about the EPLs is typically maintained in an EPL data file. Price information displayed by the EPLs is obtained from a price look-up (PLU) data file and stored within an EPL price change record.
Since a transaction establishment may contain thousands of EPLs, the EPLs typically include low-cost components, including low-cost LCDs. The LCD of a typically EPL has segments which are either on or off. When turned on, a segment appears dark. When turned off, the segment appears semi-transparent. Alphanumeric characters have a maximum of seven segments. Special characters, such as the dollar and cents signs, require three additional segments. Thus, each character typically contains seven to twelve segments. The segments are physically separated from one another to provide paths for wiring to each segment. Thus, the term segment as used herein refers only to the areas of each character that appear dark when turned on.
Unfortunately, a typical low-cost LCD is difficult to read. Polarization limits visibility in both vertical and horizontal directions. Thus, use of such LCDs in EPLs requires customers to adjust viewing angle to clearly see prices along shelves and at different shelf heights. Also, activated segments appear uniformly dull to the eye.
Therefore, it would be desirable to provide an LCD with enhanced character visibility. It would also be desirable to provide an EPL containing an LCD with enhanced character visibility.
SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention, a liquid crystal display (LCD) with enhanced character visibility is provided.
A liquid crystal display (LCDs) which has higher contrast characters than previously available LCDs, particularly LCDs used in electronic price labels. The LCD includes a number of characters containing segments including four vertical segments and three horizontal segments arranged in a figure-8 shape. The four vertical segments have a width determined by a segment width to character width ratio of about 0.208-0.283 and the three horizontal segments have a width determined by a segment height to character height ratio of about 0.100-0.150.
The LCD includes additional segments beyond the seven segments as necessary to display alphanumeric and special characters.
Thus, the LCD includes two vertical segments within the upper and lower portions of the figure-8 shape whose centerlines have been shifted to opposite sides of the character centerline to provide optimal visibility.
The LCD further includes two enhanced vertical segments whose shapes are determined jointly by two parallel lines.
It is accordingly an object of the present invention to provide an LCD with enhanced character visibility.
It is another object of the present invention to provide an LCD in which differences in segment widths are exaggerated to produce contrast.
It is another object of the present invention to provide an electronic price label (EPL) containing an LCD with enhanced character visibility.
It is another object of the present invention to provide an improved method of displaying certain characters.
REFERENCES:
patent: 4002886 (1977-01-01), Sundelin
patent: 4237460 (1980-12-01), Huguenin
patent: 4500880 (1985-02-01), Gomersall et al.
patent: 4924363 (1990-05-01), Kornelson
patent: 5172314 (1992-12-01), Poland et al.
patent: 5448226 (1995-09-01), Failing, Jr. et al.
patent: 5559528 (1996-09-01), Ravid et al.
patent: 5748568 (1998-05-01), Harrison
patent: 195 24 086 (1997-01-01), None
patent: 109473 (1984-05-01), None
patent: 834854 (1998-04-01), None
Kwan Sik Piu
Poynter William D.
Martin Paul W.
NCR Corporation
Nguyen Dung
Sikes William L.
LandOfFree
Liquid crystal display with enhanced character visibility does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid crystal display with enhanced character visibility, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid crystal display with enhanced character visibility will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2592153