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公开(公告)号：DE3480956D1
公开(公告)日：1990-02-08
申请号：DE3480956
申请日：1984-10-26
Applicant: IBM
Inventor： CLECAK NICHOLAS JEFFRIES , COX ROBERT JAMES , FENG JOSEPH SHAO-YING , LEFF JERRY
IPC: G02F1/13 , G02F1/133 , G02F1/1335 , G02F1/1337
Abstract: The orientation of the alignment layer in a raster-scanned 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. A perpendicular alignment with respect to the scan direction produces uniformly written images in both scan directions to allow high quality bidirectional writing. Parallel alignment maximizes the contrast in unidirectional writing. Antiparallel alignment increases the selective erase window and improves the resolution in unidirectionally written pages. In a preferred embodiment the liquid crystal cell includes a liquid crystal material comprising 4-octyloxy-4'-cyanobiphenyl 37.5%, 4-decyl-4'-cyanobiphenyl 36.8% weight percent and 4-undecyl-4'-cyanobiphenyl 25.7 weight percent.The drawing shows an LC cell comprising glass substrates 10, 12 having an outer anti reflection coating 8, 21. The substrate 10 carries a second anti reflection coating 10A, a conductive, metal, light absorbing layer 18, the reflective aluminium layer 20, an insulating silicon dioxide layer 19 and the alignment layer 22. The substrate 12 carries the second alignment layer 27 and a transparent conductor layer 24. The laser beam 7 sweeps in a direction perpendicular to the plane of the paper and increments vertically. The alignment layers 22, 27 are put down so that the liquid crystal directors are orientated parallel to the plane of the layers 22, 27 and perpendicular to the sweep direction of the laser beam.
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公开(公告)号：DE2816981A1
公开(公告)日：1978-11-02
申请号：DE2816981
申请日：1978-04-19
Applicant: IBM
Inventor： FENG JOSEPH SHAO-YING
Abstract: 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 to a counter when the input signal is positive. 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.
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