Organic Light-emitting Diode Microdisplays Research Articles

Atomized Scan Method for High-Definition Silicon-Based OLED Microdisplays

Silicon-based organic light-emitting diode (OLED) microdisplays are widely used in the head-mounted devices. This article proposes a novel atomized scan method for the digital driving silicon-based OLED microdisplays. By eliminating the time redundancy in the digital driving, the proposed method generates the high transmission efficiency, high lighting efficiency, high grayscale efficiency, and good linearity compared with the traditional pulsewidth modulation (PWM) scan methods. Four scan characteristics of the high-efficiency scan sequence are analyzed. The high efficient atomized scan can be obtained by implanting the low grayscale scan into the high grayscale scan. A 1.6 k $\times1.6$ k full color silicon-based OLED microdisplay, together with the hardware driving platform, is designed and implemented to verify the proposed atomized scan method. By measuring the brightness values of 256 gray levels, the atomized scan method with the blank operation can achieve high scan efficiency with the low clock frequency (57.6 MHz).

Compact and efficient RGB to RGBW data conversion method and its application in OLED microdisplays

In many electronic information displays, a colour pixel comprises three spatially distinct sub-pixels containing red, green and blue (RGB) colour filters. The option of adding a fourth white (W) sub-pixel that allows light to pass through unfiltered can significantly improve the optical efficiency of the pixel that, in turn, increases the power efficiency of the display. Such a display is called an RGBW display, and the required transformation of data format from incoming RGB to pixel RGBW is termed as “RGB to RGBW conversion.” This paper reports a method of RGB to RGBW conversion that is highly compact and efficient in terms of system resources while retaining image quality. It processes incoming data through a new colour space conversion algorithm in order to reduce the average power consumption with no noticeable visual artefacts. We explain the method and demonstrate its cost-effective and power-effective implementation for the specific case of an organic light emitting diode microdisplay.

Aspects of a head-mounted eye-tracker based on a bidirectional OLED microdisplay

In today's mobile world, small and lightweight information systems are becoming increasingly important. Microdisplays are the base for several near-to-eye display devices. The addition of an integrated image sensor significantly boosts the range of applications. This paper describes the base-building block for these systems: the bidirectional organic light-emitting diode microdisplay. A small and lightweight optic design, an eye-tracking algorithm, and interaction concepts are also presented.

Design on general development platform for FPD systems

In this paper, a multi-functional development platform for flat panel display (FPD) development is proposed. With the proposed development platforms, a variety of FPD devices, including organic light-emitting diode (OLED) screens, liquid crystal display (LCD) screens with touchscreens, OLED microdisplay screens, etc., can be directly and instantly connected, examined and utilized. A field-programmable gate array (FPGA) is used in the development system to drive different types of FPD devices, and ARM11 S3C6410 is used as the application processor to provide various services. The development system uses Linux as the system kernel, Qt for Embedded Linux as the UI framework, various system libraries for video and audio services, and a custom-made user engine for fine-polished appearance and behavior. The development platform has been used not only in testing and verification of the FPD devices, but also in building OLED-powered handheld digital devices, shortening the development cycle from OLED devices to mature application products.

Towards organic light-emitting diode microdisplays with sub-pixel patterning

We report on solution processed top-emitting organic light-emitting diodes (TEOLEDs) that are compatible with TFT- and CMOS-substrates, thus being applicable in full-color microdisplays. In this device geometry TEOLEDs offer highly tunable and controllable color-coordinates. Compared to the standard sRGB-colorspace the color gamut is increased by 18%. The CIE ( Commission internationale de l’éclairage) color coordinates are more saturated in the red and green spectral region and comparable in the blue region. Brightness levels of 1000 cd/m 2 are reached at voltages below 7 V for all colors which is within the operating voltage range of CMOS-backplanes. The polymeric emitters are crosslinkable and can be patterned in a UV-lithography process. The achieved minimum feature size is suitable for high resolution microdisplays.