Electroluminescent display driver device

An EL display device comprising:

• an EL display panel having a plurality of scan electrodes, a plurality of data electrodes, and a plurality of EL elements formed at intersections of said scan electrodes and said data electrodes;
• a scan electrode drive circuit to sequentially output a scan voltage having a differing polarity with each positive and negative field to said plurality of scan electrodes;
• and
• a data electrode drive circuit to output data voltage to said plurality of data electrodes;
• and
• a voltage supply circuit for generating said scan voltage and said data voltage by supplying to said scan electrode drive circuit, in said positive field, a positive polarity scan voltage and a first offset voltage which is higher than ground level;
• wherein
• said scan electrode drive circuit is further for setting voltages of said plurality of scan electrodes to be said first offset voltage in said positive field, together with outputting said positive polarity scan voltage to said plurality of scan electrodes during electroluminescence operation;
• said data voltage has a modulation voltage to determine electroluminescence of said plurality of EL elements;
• and
• said voltage supply circuit is for supplying said modulation voltage and a second offset voltage which is higher than ground level to said data electrode drive circuit as said data voltage in said negative field.

An EL display device comprising:

• an EL display panel having a plurality of scan electrodes, a plurality of data electrodes, and a plurality of EL elements formed at intersections of said scan electrodes and said data electrodes;
• a scan electrode drive circuit to sequentially output a scan voltage having a differing polarity with each positive and negative field to said plurality of scan electrodes;
• and
• a data electrode drive circuit to output data voltage to said plurality of data electrodes;
• a voltage supply circuit for generating said scan voltage and said data voltage by supplying to said scan electrode drive circuit, in said positive field, a positive polarity scan voltage and a first offset voltage which is higher than ground level;
• first switching means for setting a power source voltage to be applied to an EL element of said EL elements during electroluminescence drive of said EL element;
• a charge collecting capacitor for collecting a charge charged in said EL element by application of said power source voltage;
• and
• second switching means for charging said EL element by a charge collected by said charge collecting capacitor prior to electroluminescence drive of said EL element, and for causing said capacitor to collect a charge charged in said EL element subsequent to electroluminescence drive of said EL element;
• wherein said scan electrode drive circuit is further for setting voltages of said plurality of scan electrodes to be said first offset voltage in said positive field, together with outputting said positive polarity scan voltage to said plurality of scan electrodes during electroluminescence operation.

An EL display device comprising:

• an EL display panel having a plurality of scan electrodes, a plurality of data electrodes, and a plurality of EL elements formed at intersections of said scan electrodes and said data electrodes;
• a scan electrode drive circuit to sequentially output a scan voltage having a polarity alternating in correspondence with an alternation in positive and negative field of operational cycles of said device to said plurality of scan electrodes;
• and
• a data electrode drive circuit to output a data voltage to said plurality of data electrodes;
• and
• a voltage supply circuit for generating said scan voltage and said data voltage by supplying to said scan electrode drive circuit, in said positive field, a positive polarity scan voltage and a first offset voltage which is higher than ground level;
• wherein
• said scan electrode drive circuit is further for setting voltages of said plurality of scan electrodes to be said first offset voltage in said positive field, together with outputting said positive polarity scan voltage to said plurality of scan electrodes doing electroluminescence operation;
• said data electrode drive circuit is for outputting, as one of said data voltages and in a relationship with said scan voltage, a modulation voltage to cause one of said EL elements to selectively emit light;
• and
• said voltage supply circuit supplying said modulation voltage to said data electrode drive circuit, said voltage supply circuit including first switching means for supplying said modulation voltage during electroluminescence drive of said EL element, a charge collecting capacitor, and a second switching means for charging of said EL element via said data electrode drive circuit by a charge collected by said capacitor for charge collecting use prior to electroluminescence drive of said EL element, and for charging said charge collecting capacitor to collect via said data electrode drive circuit a charge charged in said EL element subsequently to electroluminescence drive of said EL element.

An EL display device comprising:

• an EL display panel having a plurality of scan electrodes, a plurality of data electrodes, and a plurality of EL elements are formed at intersections of said scan electrodes and said data electrodes;
• a scan electrode drive circuit to sequentially output a scan voltage having a differing polarity with each positive and negative field to said plurality of scan electrodes;
• and
• a data electrode drive circuit to output data voltage to said plurality of data electrodes;
• and
• a voltage supply circuit for generating said scan voltage and said data voltage by supplying a modulation voltage to determine electroluminescence of said plurality of EL elements and an offset voltage which is higher than ground level to said data electrode drive circuit;
• wherein said data electrode drive circuit, in said negative field, with respect to a data electrode of an EL element caused to be in an electroluminescent state, is further for setting a voltage thereof to be said modulation voltage, and with respect to a data electrode of an EL element caused to be in a non-electroluminescent state, is further for setting a voltage thereof to be said offset voltage;
• said voltage supply circuit is for supplying a voltage lower than said modulation voltage by an amount corresponding to said offset voltage and ground voltage to said data electrode drive circuit as said data voltage;
• and
• said data electrode drive circuit, in said positive field, with respect to a data electrode of an EL element caused to be in an electroluminescent state, is for setting a voltage thereof to be said ground voltage, and with respect to a data electrode of an EL element caused to be in a non-electroluminescent state, is for setting a voltage thereof to be a voltage lower than said modulation voltage by an amount corresponding to said offset voltage.

An EL display device having an EL element, said device comprising:

• a first drive circuit to output a first drive voltage to a first electrode of said EL element and a second drive circuit to output a second drive voltage to a second electrode of said EL element so that a drive voltage pulse with an alternating positive and negative polarity is applied between said first and second electrodes, said first and second electrodes forming a pair of electrodes;
• wherein said device further comprises a voltage supply circuit for generating a voltage required to generate said alternating positive and negative polarity drive voltage pulse in said first and second drive circuits by supplying a first main voltage to generate said positive polarity drive voltage pulse and a first offset voltage which is higher than ground level to a first one of said first and second drive circuits,
• said first main voltage is such that, in a relationship with said second drive voltage, voltage applied between said pair of electrodes becomes at least a threshold voltage for causing said EL element to emit light,
• said first off set voltage is such that, in a relationship with said second drive voltage, voltage applied between said pair of electrodes becomes lower than a threshold voltage,
• said voltage supply circuit is further for supplying a modulation voltage to generate said negative polarity drive voltage pulse and a second offset voltage which is higher than ground level to a second one of said first and second drive circuits, and
• said second offset voltage is such that, in a relationship with a drive voltage of said first one of said first and second drive circuits, voltage applied between said pair of electrodes becomes lower than said threshold voltage.

A display device comprising:

• a display panel having a plurality of scan electrodes, a plurality of data electrodes, and a plurality of display elements formed at intersections of said scan electrodes and said data electrodes;
• a scan electrode drive circuit to input a first power voltage from a first power supply through a pair of power supply lines and sequentially output a scan voltage;
• and
• a data electrode drive circuit to input a second power voltage from a second power supply through a pair of power supply lines and sequentially output a data voltage;
• wherein a positive terminal of said first power supply is connected to a negative terminal of said second power supply with a first switch interposed therebetween,
• a negative terminal of said first power supply is connected to a positive terminal of said second power supply with a second switch interposed therebetween,
• an operational cycle of said display device includes a positive field and a negative field, one of said first and second switches being turned on alternately in each of said positive and negative fields.

An EL display device comprising:

• an EL display panel having a plurality of scan electrodes, a plurality of data electrodes, and a plurality of EL elements formed at intersections of said scan electrodes and said data electrodes;
• a scan electrode drive circuit to sequentially output a scan voltage having a polarity alternating in correspondence with an alternation in positive and negative fields of an operational cycle of said device to said plurality of scan electrodes;
• a data electrode drive circuit to output a data voltage to said plurality of data electrodes;
• and
• a voltage supply circuit for generating said scan voltage and said data voltage by supplying to said scan electrode drive circuit, in a pre-determined field, a scan voltage with predetermined polarity scan voltage and a first offset voltage which has a pre-determined voltage which is different from ground level;
• wherein said scan electrode drive circuit is further for setting voltages of said plurality of scan electrodes to be said first offset voltage in said pre-determined field, together with outputting said pre-determined polarity scan voltage to said plurality of scan electrodes during electroluminescence operation,
• said data voltage has a modulation voltage to determine electroluminescence of said plurality of EL elements,
• said first offset voltage is established at a voltage level identical to said modulation voltage,
• said voltage supply circuit has a first power source and a second power source, and
• said voltage supply circuit includes first switching means for connecting a positive electrode of said first power source and a negative electrode of said second power source so that when said modulation voltage is supplied from said first power source positive electrode to said data electrode drive circuit and said first switching means has been switched on, said first offset voltage equal to said modulation voltage and said predetermined polarity scan voltage arc respectively supplied to said scan electrode drive circuit from said second power source negative electrode of said second power source and positive electrode of said first power source.