Circuit and method for driving an array of light emitting pixels
AssigneeIgnis Innovation Inc.
InventorsArokia Nathan, Yuriy Vygranenko, Shahin Jafarabadiashtiani, Peyman Servati
Life of this patent
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Abstract
A technique for driving a column of pixels that include light emitting elements. The technique incorporates feedback data provided from feedback data sources connected to the data line and to feedback line of the array, pixel driving circuit with feedback path. The technique can also include block of the reference elements for input signal corrections.
Claims19
A pixel circuit for use in a display, the display comprising a plurality of pixels with each pixel having a select line, a signal line, and a feedback line, each of the pixels comprising:
- a light emitting element;
- a drive part for providing a drive current to the light emitting element, the drive part having a storage capacitor, a switch use transistor, a drive use transistor, and a feedback diode;
- the switch use transistor having a gate terminal connected to the select line, a first terminal connected to the signal line, and a second terminal connected to the storage capacitor,
- the drive use transistor having a gate terminal connected to the second terminal of the switch use transistor, a first terminal connected to the light emitting element, and a second terminal connected to the feedback diode, and
- the feedback switch having a gate connected to the select line, a first terminal connected to the drive use transistor, and a second terminal connected to the feedback line.
A pixel circuit for use in a display, the display comprising a plurality of pixels each pixel connected to a select line, a signal line, and a feedback line, each of the pixels comprising:
- a light emitting element;
- a drive part for providing a drive current to the light emitting element, the drive part including:
- a storage capacitor;
- a switch use transistor;
- a drive use transistor connected to the light emitting element;
- a feedback transistor having a gate connected to the select line, a first terminal connected to the drive use transistor and to the storage capacitor, and a second terminal connected to the feedback line;
- the switch use transistor having a gate terminal connected to the select line, a first terminal connected to the signal line, and a second terminal connected to the storage capacitor,
- the drive use transistor having a gate terminal connected to the second terminal of the switch use transistor, a first terminal connected to the light emitting element, and a second terminal connected to a reference potential.
A method of driving a plurality of light emitting elements arranged in a column, comprising:
- selecting one pixel of a plurality of pixels in the column via a select line, each of the pixels including a light emitting element and a current driving circuit having a storage capacitor and a switch use transistor;
- establishing, in a control unit external to the selected pixel, the desired brightness of a reference diode of the control unit according to an external reference current supplied to a current source of the control unit;
- converting in the control unit the reference current flowing through the reference diode into a corresponding voltage level;
- transmitting, by a difference amplifier in the control unit, the voltage level from the control unit to the selected pixel;
- converting in the selected pixel the voltage level into a drive current and generating a feedback voltage signal representing a drive current level to form a negative feedback loop between the selected pixel and the difference amplifier;
- the difference amplifier adjusting the voltage level in response to the feedback voltage signal from the selected pixel to establish a drive current substantially equal to the reference current;
- storing the adjusted voltage level in the selected pixel;
- and
- driving the light emitting element of the selected pixel with the drive current in accordance with the adjusted voltage level, wherein the reference diode in the control unit and the light emitting element in the selected pixel have matched fabrication characteristics.
Dependencies are inferred from the claim text.