Driving apparatus for display element

• US 3,883,778 A
• Filed: 12/03/1973
• Issued: 05/13/1975
• Est. Priority Date: 12/03/1973
• Status: Expired due to Term

• Current Assignee: Seiichi Murayama, Tetsunori Kaji
• Original Assignee: Seiichi Murayama, Tetsunori Kaji
• Inventors: Kaji, Tetsunori, Murayama, Seiichi
• Primary Examiner(s): Rolinec, R. V.
• Assistant Examiner(s): LaRoche, E. R.
• Application Number:
  US05/421,351
• Time in Patent Office: 526 Days
• Field of Search: 315/169R,169TV,2R,201,202,205,208,291,293,294,312,324,337,DIG.4,DIG.7 340/324M 178/7.3D
• US Class Current: 315/205
• CPC Class Codes: H04N 3/125 using gas discharges, e.g. plasma
• CPC Class Codes: Y10S 315/04 Dimming circuit for fluorescent lamps

Abstract

A driving apparatus for a display element comprises a plurality of sources for generating pulse-width modulated pulse signals each having a different amplitude depending on its source, an adder for adding the pulse signals from the sources together and a discharge tube to which the output of the adder is applied.

Claims

1. An apparatus comprising:

a display element;

first means for quantizing input signals representing the degree of brightness to which said display element is to be energized;

second means for digitizing the output from said first means;

a plurality of first AND gates to one of whose input terminals signals corresponding to predetermined upper bits within the output signals from said second means are applied;

a plurality of second AND gates to one of whose input terminals signals corresponding to predetermined lower bits within the output signals from said second means are applied;

third means for generating pulse signals varying in width within a predetermined range;

fourth means for applying simultaneously said pulse signals in the increasing order of their pulse width to the other input terminals of said first and second AND gates;

first and second OR gates to which the output signals from said first and second AND gates are applied, respectively;

fifth and sixth means to which the output signals from first and second OR gates are applied, for respectively generating output signals having different respective amplitudes;

seventh means for adding the outputs from said fifth and sixth means, together; and

means for supplying the output of said seventh means to said display element.

2. An apparatus according to claim 1, wherein each of said fifth and sixth means respectively comprises:

a transistor, a resistor element which is connected in series with the emitter of said transistor, a voltage source which is connected between said resistor element and ground, and a diode which is connected to the collector of said transistor, and wherein the respective outputs from each of said OR gates is applied to the base of said transistor.

3. An apparatus according to claim 1, wherein each of said fifth and sixth means comprises:

an AND gate to one of whose input terminals the output from said OR gate is applied, a pulse generator for applying pulse signals having a given period to the other input terminal of the AND gate, a transistor to whose base the output from the AND gate is applied, a resistor element connected in series with the emitter of said transistor, a voltage source connected between said resistor element and ground, and a diode connected to the collector of said transistor, and wherein the magnitude of the output can be varied with said resistor element.

4. An apparatus according to claim 1, wherein each of said fifth and sixth means comprises an AND gate to one of whose input terminals the output from said OR gate is applied, a pulse generator for applying pulse signals having a given period to the other input terminal of the AND gate, a transistor to whose base the output from the AND gate is applied, a resistor element connected to the emitter of said transistor, a voltage source connected between said resistor element and ground, and a diode connected to the collector of said transistor, and wherein the pulse frequency of the pulse signals from said pulse generator can be changed within one period of said pulse signal.

5. An apparatus comprising:

a display element;

first means for quantizing input signals representing the degree of brightness to which said display element is to be energized;

second means for digitizing the output quantization signal from said first means;

a plurality of AND gates to one of whose input terminals respective pulse output signals corresponding to predetermined upper bits within the digitized quantization signal are applied;

third means for generating pulse signals varying in width within a predetermined range;

fourth means for applying simultaneously respective pulse outputs from said third means to one input terminal of said AND gate, to the other of whose input terminals the pulse outputs for the predetermined lower bits within the digitized quantization signals are applied in the increasing order ot their pulse width;

fith means for measuring the difference of said quantization signals and said input signals;

an OR gate to which the outputs from said AND gates are respectively applied;

sixth means, to which the outputs from said fifth means and said OR gate are applied, for converting the signals applied thereto into respective separate output signals, the amplitudes of which are at different prescribed values; and

means for supplying the output from said sixth means to said display element.

6. A driving apparatus for a display element comprising:

a plurality of input terminals to which input signals, corresponding to the degree of brightness to which said display element is to be energized, are coupled;

a plurality of signal sources, coupled to said plurality of input terminals, each of which signal sources generates, in response to said input signals coupled thereto, a pulse-width modulated signal representative of the degree of brightness to which said display element is to be energized;

first means, coupled to said plurality of signal sources, for amplifying the respective pulse-width modulated signals from said signal sources by respectively different degrees of amplification, thereby providing separate pulse-width modulated signals having different amplitudes;

second means, coupled to said first means, for summing the respective separate pulse-width modulated signals having different amplitudes, to produce a summation signal; and

third means, coupled to said second means, for supplying said summation signal to said display element.

7. A driving apparatus according to claim 6, wherein each of said plurality of signal sources includes a signal source which generates analog signals representative of the difference between said input signals and a quantized representation of said Input signals.

8. A driving apparatus for a display element comprising:

a plurality of input terminals to which input signals, corresponding to the degree of brightness to which said display element is to be energized, are coupled;

a plurality of signal sources, coupled to said plurality of input terminals, each of which signal sources generates, in response to said input signals coupled thereto, a pulse-frequency modulated signal representative of the degree of brightness to which said display element is to be energized;

first means, coupled to said plurality of signal sources, for amplifying the respective pulse-frequency modulated signals from said signal sources by respectively different degrees of amplification, thereby providing separate pulse-frequency modulated signals having different amplitudes;

second means, coupled to said first means, for summing the respective separate pulse-frequency modulated signals having different amplitudes, to produce a summation signal; and

third means, coupled to said second means, for supplying said summation signal to said display element.

9. A driving apparatus according to claim 8, wherein each of said plurality of signal sources includes a signal source which generates analog signals representative of the difference between said input signals and a quantized representation of said input signals.

10. A driving apparatus for a display element comprising:

a plurality of input terminals to which input signals, corresponding to the degree of brightness to which said display element is to be energized, are coupled;

a plurality of signal sources, coupled to said plurality of input terminals, each of which signal sources generates, in response to said input signals coupled thereto, a pulse-frequency modulated signal representative of the degree of brightness to which said display element is to be energized;

first means, coupled to said plurality of signal sources, for producing a plurality of separate output signals, having respectively different numbers of pulses, in accordance with the respective pulse-frequency modulated signals generated by said plurality of signal sources;

second means, coupled to said first means, for summing said separate output signals to produce a summation signal; and

third means, coupled to said second means for supplying said summation signal to said display element.

11. A driving apparatus according to claim 10, wherein each of said plurality of signal sources includes a signal source which generates analog signals representative of the difference between said input signals and a quantized representation of said input signals.