Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
424 words
A display device comprising a liquid crystal display having at least one polariser, which liquid crystal display comprises two parallel supporting plates having facing surfaces spaced a distance d from each other and on one surface of which a pattern of line electrodes is provided and on the other surface of which a pattern of column electrodes is provided, the line electrodes crossing the column electrodes and the crossings forming a matrix of display cells, a layer of a nematic liquid crystal with a cholesteric addition being present between the supporting plates, the liquid crystal having a positive dielectric anisotropy and a natural pitch p, characterized in that the ratio d/p has a value between 0.5 and 1, the said surfaces are provided with an orientation layer which gives the average direction of the longitudinal axis of the liquid crystal molecules (director) over the layer thickness d a rotation increasing to a value between π and 2π radians and gives the molecules at one surface an angle of tilt between 0 and 70° and those at the other surface an angle of tilt between 5° and 70 0 with respect to the respective surfaces, the device further comprises a line scanning circuit for scanning, within a frame time t f , successively and periodically the line electrodes with a line selection pulse, and a column selection circuit for applying data pulses to the column electrodes during a time that a line electrode is scanned for selecting those display cells which are to be switched from a first condition to a second condition differing optically from the first, the line selection pulses, the data pulses and the frame time t f being chosen such that a display cell in the stationary "on" condition during the frame time shows a transmission which is formed by the superposition of a background level T b1 and a peak response having a peak height T 1 , a display cell in the stationary "off" condition during the frame time shows a transmission which is formed by the superposition of a background level T b2 and a peak response having peak height T 2 , and a display cell which is switched from the stationary "off" condition to the stationary "on" condition reaches said "on" condition via a transmission response curve which is formed by the superposition of a background level and a peak response having final values T b1 and T 1 , respectively, T 1 being larger than or equal to 0.5 (T b1 - T b2 ).
Claim 2
Dependent Claim
424 words
A display device comprising a liquid crystal display having at least one polariser, which liquid crystal display comprises two parallel supporting plates having facing surfaces spaced a distance d from each other and on one surface of which a pattern of line electrodes is provided and on the other surface of which a pattern of column electrodes is provided, the line electrodes crossing the column electrodes and the crossings forming a matrix of display cells, a layer of a nematic liquid crystal with a cholesteric addition being present between the supporting plates, the liquid crystal having a positive dielectric anisotropy and a natural pitch p, characterized in that the ratio d/p has a value between 0.5 and 1, the said surfaces are provided with an orientation layer which gives the average direction of the longitudinal axis of the liquid crystal molecules (director) over the layer thickness d a rotation increasing to a value between π and 2π radians and gives the molecules at one surface an angle of tilt between 0 and 70° and those at the other surface an angle of tilt between 5° and 70 0 with respect to the respective surfaces, the device further comprises a line scanning circuit for scanning, within a frame time t f , successively and periodically the line electrodes with a line selection pulse, and a column selection circuit for applying data pulses to the column electrodes during a time that a line electrode is scanned for selecting those display cells which are to be switched from a first condition to a second condition differing optically from the first, the line selection pulses, the data pulses and the frame time t f being chosen such that a display cell in the stationary "on" condition during the frame time shows a transmission which is formed by the superposition of a background level T b1 and a peak response having a peak height T 1 , a display cell in the stationary "off" condition during the frame time shows a transmission which is formed by the superposition of a background level T b2 and a peak response having peak height T 2 , and a display cell which is switched from the stationary "off" condition to the stationary "on" condition reaches said "on" condition via a transmission response curve which is formed by the superposition of a background level and a peak response having final values T b1 and T 1 , respectively, T 1 being larger than or equal to 0.5 (T b1 - T b2 ).
Claim 3
Dependent Claim
49 words
A display device as claimed in Claim 1, characterized in that a display cell which is switched from the stationary "off" condition to the stationary "on" condition shows a transmission response which during the first occurring frame time is equal to that of each of the subsequent frame times.
Claim 4
Dependent Claim
43 words
A display device as claimed in Claim 1 or 2, characterized in that the ratio d/p is approximately 0.75, the director over the layer thickness d shows a rotation increasing to 3/2π radians and the layer thickness d is smaller than 8 microns.
Claim 5
Dependent Claim
26 words
A display device as claimed in Claim 1, 2 or 3, characterized in that the front supporting plate and the rear supporting plate comprise a polariser.
Claim 6
Dependent Claim
60 words
A display device as claimed in Claim 1, 2, or 3, characterized in that it comprises a first liquid crystal display and a second liquid crystal display placed behind the first, the front supporting plate of the first display and the rear supporting plate of the second display comprising a polariser, a common polariser being present between the two displays.
Claim 7
Dependent Claim
23 words
A display device as claimed in Claim 4, characterized in that a reflector is provided on the polariser of the rear supporting plate.
Claim 8
Dependent Claim
98 words
A display device as claimed in any of the preceding Claims, characterized in that the line scanning circuit provides line selection pulses of the voltage V 1 , the column selection circuit provides data pulses of the voltage ±V c and that of the display cells which during a line time are connected to an instantaneously scanned line electrode, selected display cells convey a voltage V 1 +V c , non-selected display cells convey a voltage V 1 -V c and all the cells not connected to the instantaneously scanned line electrode convey a voltage ±V c .
Claim 9
Dependent Claim
31 words
A display device as claimed in any of the preceding Claims, characterized in that the data pulses are formed as pulses which are modulated in pulse duration by the picture information.
Claim 10
Dependent Claim
24 words
A display device as claimed in any of the preceding Claims, characterized in that it relates to a device for alphanumerical or television display.