Casio Computer Co., Ltd.

Casio Electronics Manufacturing Co., Ltd.

Casio Electronics Mfg. Co., Ltd.

Casio Electronics Manufac. Co. Ltd.

Morio Ohta

Shizuo Tsuchiya

Hideaki Inoue

Yoshito Nakano

Seiji Asaumi

Masaru Aikawa

An arrangement of the liquid crystal light shutter wherein its liquid crystal matter is two-frequency-driven by signals (or waveforms) in which frequencies (f.sub.H and f.sub.L) higher and lower than a frequency (f.sub.C), which inverts the dielectric aniostropy of the liquid crystal matter, is contained. The liquid crystal matter of this liquid crystal light shutter includes a dichroic dye, and serves to pass or absorb the light entering into the liquid crystal light shutter. This causes the liquid crystal light shutter to be opened or closed, and the liquid crystal light shutter is provided with a polarizing plate for polarizing the light passing through, or entering into this liquid crystal light shutter. The present invention relates to a second polarizing plate employed by the liquid crystal light shutter, for polarizing the light exiting the shutter.

Liquid crystal light shutter

A waveform generating apparatus for driving a liquid crystal device has a memory for storing waveform data for designating a drive waveform of the liquid crystal device and duration data for designating a duration for which the drive waveform designated by the waveform data is to be supplied, and for outputting the waveform data and the duration data in accordance with an input address designation signal. The apparatus also has a macro decoder for receiving the waveform data output from the memory and a clock signal having a predetermined period and a predetermined phase, and outputting a plurality of drive waveforms designated by the waveform data from corresponding output terminals, thereby generating predetermined waveforms.

Waveform generating apparatus for driving liquid crystal device

A method of driving a liquid crystal recording device comprises applying a drive signal to liquid crystal micro shutters defined at the intersection of common electrodes that are normal to signal electrodes. The drive signal is a signal experienced by a microshutter as a result of the application of a selected signal to the common electrode and the application of a recording signal to the signal electrode. Both the selected and recording signals contain components of frequencies grater and less than a specified frequency which causes the dielectric anistotropy of the liquid crystal to disappear. A drive signal which opens or closes microshutters for a selected period of time includes a signal whose frequency is lower than said specified frequency, and superposed waveform obtained when the signal whose frequency is loser than the specified frequency is superposed upon a signal whose frequency is higher than the specified frequency. A driving waveform which reversely sets the microshutters open or closed for the selected period of time is formed of a signal including a frequency higher than the specified frequency and a zero frequency signal. As a consequence of the application of signals of this nature to the microshutters, the temperature characteristics of the liquid crystal microshutters are improved.

Method of driving a recording apparatus

A waveform forming device comprises a light source, a liquid crystal light shutter for passing or preventing the light of the light source and a driving circuit for driving a plurality of electrodes of the liquid crystal light shutter by using drive control signals including a signal of a high frequency f.sub.H and a signal of a low frequency f.sub.L. The frequencies f.sub.H and f.sub.L are respectively higher and lower than the frequency which makes a liquid crystal dielectric anisotropy zero. The waveform forming device has a ROM in which a plurality of basic control signals are stored, a counter for addressing a desired memory areas of the ROM and a waveform selector for selecting the basic control signals. The drive control signals are formed by combining the basic control signals, thereby to provide a desired drive pattern signal.

Recording and waveform forming apparatus

A recording apparatus is capable recording information by light passed through the light shutter. When the information is recorded on to a sheet of paper, the recording apparatus controls that area on the paper where information is to be recorded, and it comprises plural AND or OR gates, counters and flip-flop circuits. The area on the paper where the information is to be recorded is indicated by an effective writing signal applied from a means located outside and recording data applied from a means located outside is recorded on to the sheet of paper responsive to this effective writing signal.

Recording apparatus

In the recording apparatus of this invention, liquid crystal light shutter operates by using the double frequency drive. The double frequency drive utilizes signals of a high frequency f.sub.H and lower frequency f.sub.L. The dielectric anisotropy of liquid crystal matrial becomes positive in the case of the frequency f.sub.L lower than crossover frequency f.sub.C and becomes negative in the case of the frequency f.sub.H higher than the frequency f.sub.C. When the data signal including the signal of the frequency f.sub.L for a final period of a writing cycle Tw, is applied to write selection electrodes and data signal electrodes, liquid crystal light shutter is kept open for the final period of the writing cycle Tw, namely, opening or closing state of the shutter which is caused during a selection period can be eliminated.

Recording apparatus with double frequency driven liquid crystal shutter

In a recording apparatus of this invention, liquid crystal light shutter operates by using the double frequency drive. The double frequency drive employs a higher frequency f.sub.H and lower frequency f.sub.L. The dielectric anisotropy becomes positive in the case of the lower frequency f.sub.L than crossover frequency f.sub.C and becomes negative in the case of the higher frequency f.sub.H than the frequency f.sub.C of liquid crystal material. The driver circuit of liquid crystal light shutter includes a delay circuit (146). Both a recording data delayed through the delay circuit (146) and a recording data formed without going through the delayed circuit (146) are produced in an LSI, to be supplied to write selecting electrodes and signal electrodes of the liquid crystal light shutter, thereby driving the liquid crystal light shutter in a time sharing manner.

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Tokyo, Japan

Morio Ohta