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US 6,580,657 B2Granted
Low-power organic light emitting diode pixel circuit
AssigneeInternational Business Machines Corporation
InventorsJames Lawrence Sanford, Eugene S. Schlig
Life of this patent
Estimating the term…
Abstract
A pixel circuit comprises an organic light emitting diode (OLED), and a static memory for storing data that represents an operational state of the OLED. In alternative embodiments, a pixel circuit may include a complementary metal oxide semiconductor (CMOS) circuit for controlling the OLED, a protection circuit for protecting the CMOS circuit from an over-voltage condition, and a current source with a field effect transistor (FET) having a static gate to source voltage that is greater than a threshold voltage of the FET.
Claims26
A pixel circuit comprising:
- a static memory for storing data that represents an operational state of a pixel;
- a first input to enable writing data into said static memory;
- a second input to enable reading data from said static memory;
- and
- wherein said static memory comprises:
- a first component through which a data signal is coupled to provide a source signal drive current;
- a second component having an input for receiving said source signal drive current from said first component, and for being driven to a state to produce at an output thereof an output drive current that represents said stored data;
- and
- a third component having an input coupled to said output of said second component, and an output coupled to said input of said second component, for providing a latch signal drive current, which is less than said source signal drive current and said output drive current of said second component, to thereby maintain said state of said second component after a removal of said source signal.
6 more elements
A display comprising an array of pixel circuits, wherein each of said pixel circuits comprises:
- a light emitting device;
- a static memory for storing data that represents an operational state of said light emitting device;
- a first control input for enabling the writing of data to said static memory;
- a second control input for enabling the reading of data from said static memory, wherein said data represents a luminous state of said light emitting device;
- and
- wherein said static memory comprises:
- a first component through which a data signal is coupled to provide a source signal drive current;
- a second component having an input for receiving said source signal drive current from said first component, and for being driven to a state to produce at an output thereof an output drive current that represents said stored data;
- and
- a third component having an input coupled to said output of said second component, and an output coupled to said input of said second component, for providing a latch signal drive current, which is less than said source signal drive current and said output drive current of said second component, to thereby maintain said state of said second component after a removal of said source signal.
7 more elements
A static memory cell circuit comprising:
- a semiconductor memory cell;
- a first control input for writing data into said memory cell;
- a second control input for reading data from said memory cell;
- and
- wherein said memory cell comprises:
- a first component through which a data signal is coupled to provide a source signal drive current;
- a second component having an input for receiving said source signal drive current from said first component, and for being driven to a state to produce at an output thereof an output drive current that represents said written data;
- and
- a third component having an input coupled to said output of said second component, and an output coupled to said input of said second component, for providing a latch signal drive current, which is less than said source signal drive current and said output drive current of said second component, to thereby maintain said state of said second component after a removal of said source signal.
6 more elements
A static memory comprising:
- an array of semiconductor circuits, each semiconductor circuit being capable of storing a bit of data;
- a first control input connected to each of said semiconductor circuits for writing data;
- a second control input connected to each of said semiconductor circuits for reading data;
- and
- wherein each of said semiconductor circuits comprises:
- a first component through which a data signal is coupled to provide a source signal drive current;
- a second component having an input for receiving said source signal drive current from said first component, and for being driven to a state to produce at an output thereof an output drive current that represents said stored data;
- and
- a third component having an input coupled to said output of said second component, and an output coupled to said input of said second component, for providing a latch signal drive current, which is less than said source signal drive current and said output drive current of said second component, to thereby maintain said state of said second component after a removal of said source signal.
6 more elements
Dependencies are inferred from the claim text.