Honeywell International Inc.

Jerry A Roush

Kalluri R Sarma

John T Schmidt

John F L Schmidt

Sonia R Dodd

John Schmidt

An improved AM OLED pixel circuit and method of wide dynamic range dimming for AM OLED displays are disclosed that maintain color balance throughout the dimming range, and also maintain the uniformity of the luminance and chromaticity of the display at low gray-levels as the display is dimmed to lower luminance values. As such, AM OLED displays can meet the stringent color/dimming specifications required for existing and future avionics, cockpit, and hand-held military device display applications. Essentially, the OLED pixel circuit and method of dimming that are disclosed use Pulse Width Modulation (PWM) of the OLED pixel current to achieve the desired display luminance. Two example circuits are disclosed that externally PW modulate the common cathode voltage or common power supply voltage to modulate the OLED current in order to achieve the desired display luminance. Three example circuits are disclosed that incorporate additional transistor switches in the pixel circuit to modulate the OLED current during the frame time. By PWM of the OLED current, in combination with data voltage (or current) modulation, wide dynamic range dimming can be achieved while maintaining the color balance and the luminance and chromaticity uniformity required over the surface of the display involved.

Active matrix organic light emitting diode display

Apparatus, systems, and methods are provided for controlling the luminance of a display. One apparatus includes a pre-charge circuit configured to supply a pre-charge voltage to a column of LED pixels, a programming circuit configured to supply current to the column, and a switch configured to selectively couple the pre-charge circuit or the programming circuit to the column. A system includes an array of LED pixels arranged in a plurality of columns. A plurality of pre-charge circuits, each configured to selectively supply a pre-charge voltage to at least one column of pixels, and a plurality of current sources, each configured to selectively supply current to at least one column of pixels are also included. One method includes determining a pre-charge voltage for each of a plurality of columns based on a target luminance level selected from the plurality of luminance levels and supplying the determined pre-charge voltages to the columns.

Hybrid driver for light-emitting diode displays

Apparatus, systems, and methods are provided for dimming pixels on an active matrix light-emitting diode display. One apparatus includes an LED couplable between a voltage source and ground. First and second pulse-width modulation (PWM) drivers are also coupled to the LED. A system includes a plurality of LEDs forming a plurality of rows coupled between a voltage source and ground. A plurality of PWM drivers, each coupled to each of the LEDs in one of the plurality of rows, and a global PWM driver coupled to each of the plurality of LEDs in each of the plurality of rows are also included. One method includes providing current to each LED of a row of LEDs for a first portion of a cycle via a PWM driver, and providing current to each LED in the row for a second portion of the cycle via a different PWM driver.

Apparatus, systems, and methods for dimming an active matrix light-emitting diode (LED) display

A flexible conductor formed on a flexible substrate. In one embodiment, a semiconductor device is disclosed. The semiconductor device comprises a periodic structure of islands and at least one conductor. The at least one conductor comprises a series of repeating geometric features affixed to the periodic structure of islands. The geometric features of the conductor are adapted to stretch the conductor rather than break the conductor when the substrate is bent.

Growing community of inventors

Phoenix, AZ, United States of America

Jerry A Roush