Circuit and method for driving an array of light emitting pixels
First Claim
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1. 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, a feedback line, the pixel circuit 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 and a switch use transistor having a gate terminal connected to the select line, and a first terminal connected to the signal line, and a second terminal; and
an on-pixel feedback element for generating a feedback voltage representing a drive current provided to the light emitting element, the feedback signal being provided to the feedback line.
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Abstract
A technique for driving a column of pixels that include light emitting elements is presented. 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.
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Citations
21 Claims
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1. 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, a feedback line, the pixel circuit comprising:
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a light emitting element;
a drive part for providing a drive current to the light emitting element, the drive part having a storage capacitor and a switch use transistor having a gate terminal connected to the select line, and a first terminal connected to the signal line, and a second terminal; and
an on-pixel feedback element for generating a feedback voltage representing a drive current provided to the light emitting element, the feedback signal being provided to the feedback line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A pixel circuit for use in a display, the display comprising a plurality of pixels with each pixel having a first select line, a second select line, a signal line, a feedback line, the pixel circuit comprising:
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a light emitting element;
a drive part for providing a drive current to the light emitting element, the drive part comprising;
a storage capacitor;
a switch use transistor having a gate terminal connected to the first select line, a first terminal connected to the signal line and a second terminal;
a drive use transistor having a gate terminal connected to the second terminal of the switch use transistor, a first terminal and a second terminal connected to the light emitting element; and
an on-pixel feedback circuit for generating a feedback voltage representing a drive current provided to the light emitting element, the feedback circuit comprising;
a resistor connected between the second terminal of said drive use transistor and a potential; and
a feedback transistor having a gate connected to the second select line, a first terminal connected to the first terminal of the drive use transistor and a second terminal connected to the feedback line. - View Dependent Claims (14, 15, 19, 20)
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16. 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, a feedback line, the pixel circuit comprising:
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a light emitting element;
a drive part for providing a drive current to the light emitting element, the drive part comprising;
a storage capacitor;
a switch use transistor having a gate terminal connected to the select line, a first terminal connected to the signal line and a second terminal;
a drive use transistor having a gate terminal connected to the second terminal of the switch use transistor, a first terminal and a second terminal connected to the light emitting element; and
an on-pixel feedback circuit for generating a feedback voltage representing a drive current provided to the light emitting element, the feedback circuit comprising;
a resistor connected between the second terminal of said drive use transistor and a potential; and
a feedback transistor having a gate connected to the select line, a first terminal connected to the first terminal of the drive use transistor and a second terminal connected to the feedback line. - View Dependent Claims (17)
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18. A display device, comprising:
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a select line;
a signal line to which a voltage signal in accordance with both brightness and feedback information is supplied;
a feedback line to which a feedback voltage signal in accordance with current level of drive current is supplied;
a plurality of pixels forming an array of pixels, each pixel of the plurality formed on a substrate at an intersecting portion of said scanning line and said signal and feedback lines, each pixel comprising;
a light emitting element;
a current driving circuit having a storage capacitor and a switch use transistor; and
a feedback circuit to provide feedback signals representing a current output of said current driving circuit;
a display column control circuit for receiving input signals, adjusting the input signals using a reference circuit formed on the substrate at each column, and modifying the input signals in response to the feedback signals from pixels in the column to produce a desired brightness level of said light emitting element in a selected pixel; and
a selecting line drive circuit for successively activating selecting lines.
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21. A method of driving a plurality of light emitting elements arranged in a column at a desired brightness, comprising the steps of:
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selecting one pixel of a plurality of pixels in the column;
establishing the desired brightness of a reference light emitting element by adjusting a reference current flowing through the light emitting element in response to a photocurrent from a photo-sensor that is optically coupled with the reference light emitting element;
converting the reference current into a corresponding voltage level;
transmitting the voltage level to the selected pixel;
converting the voltage level into a drive current and generating a feedback signal representing a drive current level;
adjusting the voltage level in response to the feedback signal from the selected pixel to establish a drive current substantially equal to the reference current;
storing the adjusted voltage level; and
driving the light emitting element with the drive current in accordance with the adjusted voltage level to produce the desired brightness level in the pixel.
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Specification