Method for driving a ferroelectric liquid crystal optical apparatus using superposed DC and AC driving pulses to attain intermediate tones
First Claim
1. A method for driving a liquid crystal optical apparatus, forming pixels in the form of a matrix by providing the ferroelectric liquid crystal having AC stabilizing effect between a scanning electrode group and a control electrode group, whereina first pulse is applied to the pixels in order to initialize the ferroelectric liquid crystal to a saturated reverse condition depending on the voltage difference between the signal supplied to the scanning electrode group and the signal supplied to the control electrode,a second pulse is applied to initialize the ferroelectric liquid crystal to a saturated response condition or a third pulse where a high frequency AC pulse is superposed to the second pulse, is thereafter applied to initialize the liquid crystal to the desired response condition including intermediatetone,an AC pulse group is then applied to hold the desired response condition,a mean voltage level of the first and second pulses and a mean voltage level of the first and third pulses are 0, anda high frequency AC pulse superposed to the second pulse is controlled depending on the display tone.
1 Assignment
0 Petitions
Accused Products
Abstract
The present invention realizes display of the intermediate tone by shortening the selection period of the one scanning line and setting a mean voltage level applied to the pixels to 0 by selectively applying the pulse, to the pixels, for initializing the ferroelectric liquid crystal to the saturated reverse response condition and the pulse superposing the high frequency AC pulse to the pulse having a mean voltage of 0 for such pulse and then applying the AC pulse which holds the response condition of ferroelectric liquid crystal while such pulse group is not applied to the pixels, and moreover by controlling a voltage value or duty (rate of the period for applying high frequency AC pulse and the period for not applying the pulse) of the high frequency AC pulse to be superposed to such pulse depending on the display tone.
26 Citations
8 Claims
-
1. A method for driving a liquid crystal optical apparatus, forming pixels in the form of a matrix by providing the ferroelectric liquid crystal having AC stabilizing effect between a scanning electrode group and a control electrode group, wherein
a first pulse is applied to the pixels in order to initialize the ferroelectric liquid crystal to a saturated reverse condition depending on the voltage difference between the signal supplied to the scanning electrode group and the signal supplied to the control electrode, a second pulse is applied to initialize the ferroelectric liquid crystal to a saturated response condition or a third pulse where a high frequency AC pulse is superposed to the second pulse, is thereafter applied to initialize the liquid crystal to the desired response condition including intermediate tone, an AC pulse group is then applied to hold the desired response condition, a mean voltage level of the first and second pulses and a mean voltage level of the first and third pulses are 0, and a high frequency AC pulse superposed to the second pulse is controlled depending on the display tone.
-
5. A method for driving liquid crystal optical apparatus, comprising pixels providing ferroelectric liquid crystal having AC stabilizing effect between two electrodes, where;
-
a pulse including the DC pulse element for initializing the pixels to a saturated reverse response condition, a pulse superposing a high frequency AC pulse to the DC pulse of reverse polarity which is symmetrical to the DC pulse element in order to initialize the ferroelectric liquid crystal to a desired response condition including intermediate tone, and a high frequency AC pulse to hold the desired response condition are sequentially applied to the pixels and said high frequency AC pulse superposed to the DC element is controlled depending on the display tone.
-
-
7. A method for driving a liquid crystal optical apparatus, forming matrix-type pixels by providing
ferroelectric liquid crystal having AC stabilizing effect between a scanning electrode group and a control electrode group, where initialization signals are sequentially supplied to the scanning electrode group, a selection signal is supplied thereto following the initialization signals and a nonselection signal is supplied when the initialization signals and selection signal are not supplied, a desired signal is supplied to the control electrode group, after the ferroelectric liquid crystal is initialized to a saturated reverse response condition depending on the voltage difference between the desired signal and initialization signals, a pulse superposing a high frequency AC pulse to the DC pulse is applied in order to initialize the ferroelectric liquid crystal to the desired response condition depending on the voltage difference between the desired signal and selection signal, an AC pulse which holds the desired response condition of the ferroelectric liquid crystal is applied depending on the voltage difference between the desired signal and nonselection signal, a mean voltage level applied to the ferroelectric liquid crystal is 0, and said high frequency AC pulse superposed to the DC pulse is controlled depending on the display tone.
Specification
-
- Resources
-
Current AssigneeSeikosha Co., Ltd.
-
Original AssigneeSeikosha Co., Ltd.
-
InventorsFujita, Masanori
-
Primary Examiner(s)Miller, Stanley D.
-
Assistant Examiner(s)Gallivan, Richard
-
Application NumberUS07/192,589Time in Patent Office386 DaysField of Search350/332, 350/333, 350/350 S, 340/765, 340/784, 340/805US Class Current345/97CPC Class CodesG09G 2310/06 Details of flat display dri...G09G 3/3629 using liquid crystals havin...
