Method and apparatus for controlling a gas discharge display device

Claim 3

A method of controlling a gas discharge display apparatus in accordance with claim 1, wherein the amplitude value of the sustaining voltage at the time of writing is increased to a maximum sustaining value, said maximum sustaining amplitude value being less than that of the firing voltage of the display apparatus.

Claim 4

A method of controlling a gas discharge display apparatus in accordance with claim 1, wherein the amplitude value of the sustaining voltage at the time of erasing is altered by being decreased to a minimum sustaining voltage amplitude value.

Claim 5

A method of controlling a gas discharge display apparatus as claimed in claim 1, wherein the frequency value of the sustaining voltage is altered by being reduced at the time of erasure to a minimum frequency value required to sustain a discharge.

Claim 6

A method of controlling a gas discharge display apparatus as claimed in claim 1, wherein the frequency of at least one of the AC voltage impressed upon the addressing instrument and the sustaining voltage is varied during erasing.

Claim 7

Apparatus for controlling the writing and erasing of information upon a gas discharged display device comprising an envelope for sealing an ionizable gas therein, and first and second sets of electrodes spaced from each other and defining intersecting points as to each other, establishing thereby discrete points where information may be written and erased, said apparatus comprising: a. an addressing instrument disposable at a selected one of the discrete points of said gas discharge display device; b. source means for applying an AC control voltage of selected amplitude and frequency values to said addressing instrument whereby a corresponding AC voltage is impressed upon the selected discrete point of said gas discharge display device; c. sustaining means for impressing a sustaining voltage of selected amplitude and frequency values between the electrodes of the first and second sets whereby the sustaining voltage is applied to each discrete display point of said gas discharge display device; and d. erasing means for varying at least one of said amplitude and frequency values of the sustaining voltage from the selected value to terminate the discharge at the discrete display point where the addressing instrument is disposed, said addressing instrument having an AC control voltage applied thereto during erasing which has at least the same said selected amplitude value as the said AC control voltage applied thereto during writing.

Claim 8

Apparatus for controlling the writing and erasing of information upon a gas discharged display device comprising an envelope for sealing an ionizable gas therein, and first and second sets of electrodes spaced from each other and defining intersecting points as to each other, establishing thereby discrete points where information may be written and erased, said apparatus comprising: a. an addressing instrument disposable at a selected one of the discrete points of said gas discharge display device; b. source means for applying an AC control voltage of selected amplitude and frequency values to said addressing instrument whereby a corresponding AC voltage is impressed upon the selected discrete point of said gas discharge display device; c. sustaining means for impressing a sustaining voltage of selected amplitude and frequency values between the electrodes of the first and second sets whereby the sustaining voltage is applied to each discrete display point of said gas discharge display device; and d. erasing means for varying at least one of said amplitude and frequency values of the sustaining voltage from the selected value to terminate the discharge at the discrete display point where the addressing instrument is disposed, said addressing instrument having an AC control voltage applied thereto during erasing which has at least the same said selected amplitude value as the said AC control voltage applied thereto during writing.

Claim 9

Apparatus as claimed in claim 6, wherein there is further provided first and second addressing means respectively coupled to said first and second sets of electrodes for selectively applying an addressing signal to a selected electrode of each of said first and second sets to establish a discharge at the corresponding intersection of the said selected electrodes thereby to achieve writing on said discharge display apparatus.

Claim 10

Apparatus as claimed in claim 6, wherein said gas discharge display device has a maximum amplitude value of its sustaining voltage which is slightly less than its firing voltage and a minimum sustaining voltage amplitude value, said sustaining means selecting the sustaining voltage amplitude value to be essentially equal to the said maximum sustaining voltage amplitude value during writing.

Claim 11

Apparatus as claimed in claim 8, wherein said erasing means reduces the amplitude value of the sustaining voltage output of said sustaining means to essentially the said minimum sustaining voltage amplitude value, during erasing.

Claim 12

Apparatus for controlling the writing and erasing of information upon a gas discharge display device comprising an envelope for sealing an ionizable gas therein, first and second sets of electrodes spaced from each other by the ionizable gas and intersecting each other to define discrete points where information may be written and erased, said apparatus comprising: a. an addressing instrument disposable at a selected one of the discrete points of said gas discharge display device; b. source means for applying an AC control voltage to said addressing instrument whereby a corresponding AC voltage is impressed upon the selected discrete point of said gas discharge display device; c. sustaining means for impressing a sustaining voltage of a selected level between the electrodes of the first and second sets whereby the sustaining voltage is impressed at each discrete point of said gas discharge display device; and d. erasing means for varying the sustaining voltage from the selected level to terminate the discharge across the discrete point where the addressing instrument is disposed, said erasing means including means for dividing the frequency of the sustaining voltage to be applied to the electrodes of said gas discharge display device.

Claim 13

Apparatus for controlling the writing and erasing of information upon a gas discharge display device comprising an envelope for sealing an ionizable gas therein, first and second sets of electrodes spaced from each other by the ionizable gas and intersecting each other to define discrete points where information may be written and erased, said apparatus comprising: a. an addressing instrument disposable at a selected one of the discrete points of said gas discharge display device; b. source means for applying an AC control voltage to said addressing instrument whereby a corresponding AC voltage is impressed upon the selected discrete point of said gas discharge display device; c. sustaining means for impressing a sustaining voltage of a selected level between the electrodes of the first and second sets whereby the sustaining voltage is impressed at each discrete point of said gas discharge display device; and d. erasing means for varying the sustaining voltage from the selected level to terminate the discharge across the discrete point where the addressing instrument is disposed, said erasing means including means for dividing the frequency of the sustaining voltage to be applied to the electrodes of said gas discharge display device.

Claim 14

Apparatus for controlling as claimed in claim 6, wherein said erasing means varies the amplitude of the sustaining voltage.

Claim 15

Apparatus for controlling as claimed in claim 6, wherein said erasing means varies the frequency of the sustaining voltage.

Claim 16

A method of controlling a gas discharge display apparatus as claimed in claim 1, wherein the frequency of the sustaining voltage is varied at the time of erasure.

Claim 17

A method as recited in claim 1, wherein: the sustaining voltage comprises a train of bipolar pulses applied in alternating succession to said first and second sets of electrodes, and the AC control voltage is sinusoidal, one half period thereof exceeding the interval of successive pulses of the bipolar pulse train.

Claim 20

A method as recited in claim 15 wherein: the sustaining voltage comprises a train of bipolar pulses applied in alternating succession to said first and second sets of electrodes, and the AC control voltage is sinusoidal, one half period thereof exceeding the interval of successive pulses of the bipolar pulse train.

Claim 23

A method as recited in claim 17, wherein: the sustaining voltage comprises a train of bipolar pulses applied in alternating succession to said first and second sets of electrodes, and the AC control voltage is sinusoidal, one half period thereof exceeding the interval of successive pulses of the bipolar pulse train.

Claim 24

A method of controlling a gas discharge display apparatus as claimed in claim 17, wherein the frequency of at least one of the AC voltage impressed upon the writing instrument and the sustaining voltage is varied during erasing.

Claim 27

Apparatus for controlling a gas discharge display device having an ionizable gas therein and first and second sets of electrodes disposed in spaced planes and intersecting relationship, defining therebetween a discharge display region at each such intersection and thereby a corresponding, discrete display position, comprising means for applying a sustaining voltage to said sets of electrodes of an amplitude value selected to be sufficient to maintain a wall charge in said device in each display region at which a discharge is occurring, an addressing instrument for positioning at a selected display position, means for applying an AC control voltage to the instrument, said instrument being effective to write in said display device at a selected display position by positioning the instrument, with the AC control voltage applied thereto, at the selected position while the sustaining voltage is applied to said sets of electrodes, means fr erasing said device at a selected display position at which the instrument, having the AC control voltage applied thereto, is positioned, said erasing means altering at least one of the frequency and amplitude values of the sustain voltage, said sustain voltage at all times having amplitude and frequency values sufficient to produce a wall voltage for maintaining an already existing discharge, and the values thereof being selected with respect to those of the AC control voltage to produce, in the write operation a composite voltage of sufficient amplitude and appropriate frequency for initiating a discharge and producing a resultant wall voltage thereafter maintainable by said sustaining voltage alone, for sustaining the discharge, and to result, in the erase operation, in a composite voltage which effects discharging of an existing wall voltage but which is not sufficient to maintain the wall voltage, thereby terminating the discharge.

Claim 28

Apparatus for controlling a gas discharge display device having an ionizable gas therein and first and second sets of electrodes disposed in spaced planes and intersecting relationship, defining therebetween a discharge display region at each such intersection and thereby a corresponding, discrete display position, comprising means for applying a sustaining voltage to said sets of electrodes of an amplitude value selected to be sufficient to maintain a wall charge in said device in each display region at which a discharge is occurring, an addressing instrument for positioning at a selected display position, means for applying an AC control voltage to the instrument, said instrument being effective to write in said display device at a selected display position by positioning the instrument, with the AC control voltage applied thereto, at the selected position while the sustaining voltage is applied to said sets of electrodes, means fr erasing said device at a selected display position at which the instrument, having the AC control voltage applied thereto, is positioned, said erasing means altering at least one of the frequency and amplitude values of the sustain voltage, said sustain voltage at all times having amplitude and frequency values sufficient to produce a wall voltage for maintaining an already existing discharge, and the values thereof being selected with respect to those of the AC control voltage to produce, in the write operation a composite voltage of sufficient amplitude and appropriate frequency for initiating a discharge and producing a resultant wall voltage thereafter maintainable by said sustaining voltage alone, for sustaining the discharge, and to result, in the erase operation, in a composite voltage which effects discharging of an existing wall voltage but which is not sufficient to maintain the wall voltage, thereby terminating the discharge.