Circuit and method for generating gray scale in gaseous discharge panels

A circuit for generating a gray scale display in a gas discharge display/memory cell from a video information analog signal, said cell having at least two spaced apart electrodes, comprising:

• a source of said video signal;
• means for storing a sample of said video signal;
• means for selectively connecting said storage means to said video signal source to store a sample having a potential porportional to the magnitude of said video signal when said sample is stored;
• means for generating a trigger signal from said sample, said trigger signal having a wave form with at least one dimension proportional to the potential of said sample;
• and
• means for applying said trigger signal from said trigger signal generating means to said cell wherein said trigger signal applying means is connected to one of said electrodes defining said cell for applying a predetermined potential thereto and wherein said trigger signal applying means removes said predetermined potential to apply said trigger signal to said electrode.

A circuit for generating a gray scale display in a gas discharge display/memory cell from a video information analog signal, said cell having at least two spaced apart electrodes, comprising:

• a source of said video signal;
• means for storing a sample of said video signal;
• means for selectively connecting said storage means to said video signal source to store a sample having a potential proportional to the magnitude of said video signal when said sample is stored;
• means for generating a trigger signal from said sample, said trigger signal having a wave form with at least one dimension proportional to the potential of said sample;
• and
• means for applying said trigger signal from said trigger signal generating means to said cell wherein said trigger signal applying means includes a source of a predetermined potential and a normally closed switch connected between said potential source and the junction of said storage means and one of said electrodes defining said cell and wherein said switch is opened to apply said trigger signal to said electrode.

A circuit for generating a gray scale display in a multiple cell gas discharge display/memory panel from a video information analog signal, comprising:

• a source of said video signal;
• means for storing a plurality of samples of said video signal;
• means for selectively connecting said storage means to said video signal source to store a plurality of samples, each of said samples having a potential proportional to the magnitude of said video signal when said sample was taken;
• means for generating a trigger signal from each of said samples, said trigger signal having a wave form with at least one dimension proportional to the potential of the associated one of said samples, said trigger signal generating means including means connected between said means for selectively connecting and said storage means for generating a write signal wherein said storage means responds to said write signal by generating said trigger signal;
• and
• means for applying said trigger signals to selected cells of said panel.

A method of obtaining variable light intensity from a gas discharge display/memory cell comprising the steps of:

• sampling an analog video signal to generate a sample having a potential proportional to the magnitude of said video signal when said sample was taken;
• storing said sample;
• generating a trigger signal from said stored sample, said trigger signal having a wave form with at least one dimension proportional to the potential of said sample so as to cause a gas discharge proportional to the light intensity desired;
• applying said trigger signal across said cell;
• and
• applying an alternating current maintain voltage signal to said cell of a constant magnitude insufficient to initiate a gas discharge or to maintain a sequence of gas discharges or relatively constant intensity for an indefinite length of time, the maintain voltage magnitude being sufficient to maintain a sequence of gas discharges for a number of cycles of the maintain voltage signal proportional to the selected dimension of said trigger signal.

A method of obtaining a gray scale display from a multiple cell gas discharge display/memory panel comprising the steps of:

• sampling an analog video signal at preselected time intervals to generate a plurality of samples, each of said samples having a potential proportional to the magnitude of said video signal when said sample was taken;
• storing said samples;
• generating a trigger signal from each of said stored samples, said trigger signal having a wave form with at least one dimension proportional to the potential of the associated one of said samples so as to cause a gas discharge proportional to the light intensity desired;
• applying said trigger signals across selected cells;
• and
• applying an alternating current maintain voltage signal to said selected cells of a constant magnitude insufficient to initiate a gas discharge or to maintain a sequence of gas discharges of relatively constant intensity for an indefinite length of time, the maintain voltage magnitude being sufficient to maintain a sequence of gas discharges for a number of cycles of the maintain voltage signal proportional to the selected dimension of said trigger signal.