Abstract

Display technologies have evolved from the bulky Cathode Ray Tube based displays to the latest lightweight and low power micro-Led (uLED) based flat panel displays. A display system consists of a device technology that either manipulates the incoming light or emits its own light and a controller circuit to control the behavior of these devices. This system makes up the backplane of a display technology. uLEDs due to their small size provide higher resolution and better contrast than all the previous display technologies like the LCDs and the OLEDs. Backplane system design considerations for a uLED flat panel display is the primary focus of this work. The uLEDs are arranged in a 2-D matrix on a glass substrate with each uLED driven by an arrangement of 2 transistor and 1 capacitor that make up a pixel circuit. Indium Gallium Zinc Oxide TFTs are used as the choice of transistors for this project. The backplane design considerations are done to support an active matrix of 10x10, 50x50 and 380x380 pixel count in both monochrome and color versions. The behavior of the pixel circuit is evaluated using existing TFT and uLED electrical device compact models to determine the optimal value of the storage capacitor needed for the pixel circuit operation at 30 & 60Hz refresh rates. A model board with shift registers, transistors and LEDs to mimic the operation of a 10x10 uLED array is made and a FPGA is used to control the operation of this board. A timing relationship between the row and column data latch is deduced and the impact of the row-line, column-line RC delay and the pixel transient response time is evaluated. The impact of IR losses due to the power and ground line resistances are evaluated with the help monochrome pixel circuit physical layout. A new pixel circuit to accommodate the RGB pixels is made and care is taken to minimize both the RC delay and IR losses. Finally, a low contact resistance (0.05Ω-mm2) modular packaging scheme to electrically bond the two-dimensional array of pixel circuits on glass with the electronics on the PCB and to reduce RC delay is given.

Library of Congress Subject Headings

LED lighting--Design and construction; LED lighting--Materials; Flat panel displays

Publication Date

12-2020

Document Type

Thesis

Student Type

Graduate

Degree Name

Microelectronic Engineering (MS)

Department, Program, or Center

Microelectronic Engineering (KGCOE)

Advisor

Karl D. Hirschman

Advisor/Committee Member

Robert Pearson

Advisor/Committee Member

Mark Indovina

Campus

RIT – Main Campus

Plan Codes

MCEE-MS

Download

Share

COinS