公开(公告)号：CA1247726A

公开(公告)日：1988-12-28

申请号：CA464051

申请日：1984-09-26

Applicant: IBM

Inventor： CLECAK NICHOLAS J ,  COX ROBERT J ,  FENG JOSEPH S ,  LEFF JERRY

IPC: G02F1/13 ,  G02F1/133 ,  G02F1/1335 ,  G02F1/1337 ,  G09F9/35

Abstract: ALIGNMENT LAYER ORIENTATION IN RASTER SCAN THERMALLY ADDRESSED SMECTIC LIQUID CRYSTAL DISPLAYS The orientation of the alignment layer in a rasterscanned thermally addressed smectic liquid crystal display device can be chosen relative to the writing orientation to accentuate a selected characteristic. A perpendicular alignment with respect to the scan direction produces uniformly written images in both scan directions to allow high quality bidirectional writing. In a preferred embodiment the liquid crystal cell includes a liquid crystal material comprising 4octyloxy-4'-cyanobiphenyl 37.5%, 4-decyl-4'-cyanobiphenyl 36.8% weight percent and 4-undecyl-4'-cyanobiphenyl 25.7 weight percent.

公开(公告)号：CA1081875A

公开(公告)日：1980-07-15

申请号：CA293003

申请日：1977-12-13

Applicant: IBM

Inventor： FENG JOSEPH S

IPC: H04M3/02 ,  H04M3/06 ,  H04M19/02 ,  H04M3/22 ,  G01R17/02 ,  G01R19/26

Abstract: DIGITAL MEASUREMENT OF THE DC VALUE IN AN AC SIGNAL ADAPTED TO TELEPHONE OFF-HOOK DETECTION The duty cycle of an AC telephone off-hook signal is measured by means of comparing it with the duty cycle of a known AC signal having a duty cycle of 0.5 because it has a DC component of zero. Measurement of the duty cycle in a telephone off-hook detector application involves measuring the DC portion of the signal on a pair of telephone lines from a telephone handset to an exchange. A high frequency master clock oscillator with a much higher frequency than the basic ringing voltage is used. An input signal is used to gate clock pulses when the input signal is positive to a counter. At the end of a predetermined number of clock pulses, the counter is gated into memory connected to a decoder for transmission of the decoded signal to the exchange for appropriate action.