Andrew D. Arnold

System considerations for RGBW OLED displays

Abstract— The fabrication of full-color RGBW OLED displays using a white emitter with RGB color filters has been previously described. This paper discusses the effect of several display-system factors on the important RGBW OLED display performance attributes of power consumption, lifetime, and perceived image quality. These display-system factors include the spectrum of the white OLED, the white OLED structure, the color-filter selection, the subpixel aperture ratios, and the pixel arrangement (including sub-sampling).

4.3: Lifetime- and Power-Enhanced RGBW Displays Based on White OLEDs

In this paper, we describe techniques for improving the power consumption and lifetime of full-color AMOLED displays with an RGBW pixel format. A highly efficient and stable white OLED, with color optimized for the display white point (D65) has been developed, which enables low power consumption as well as stable emission. Additionally, a novel approach for improving the lifetime of RGBW displays using subsampled R and B subpixels is discussed.

Full-color AMOLED with RGBW pixel pattern

Abstract— A full-color AMOLED display with an RGBW color filter pattern has been fabricated. Displays with this format require about one-half the power of analogous RGB displays. RGBW and RGB 2.16-in.-diagonal displays with average power consumptions of 180 and 340 mW, respectively, were characterized for a set of standard digital still camera images at a luminance of 100 cd/m2. In both cases, a white-emitting AMOLED was used as the light source, and standard LCD filters were used to provide the R, G, and B emission. The color gamuts of these displays were identical and the higher overall efficiency of the RGBW format results from two factors. First, a large fraction of a typical image is near neutral in color and can be reproduced using the white sub-pixel. Second, the white sub-pixel in an RGBW AMOLED display is highly efficient because of the absence of any color filter. The efficiency of these displays can be further enhanced by choosing a white emitter optimized to the target display white point (in this case D65). A two-emission layer configuration based upon separate yellow and blue-emitting regions is shown to be well suited for both the RGBW and RGB formats.

System design for a wide‐color‐gamut TV‐sized AMOLED display

Abstract— By using current technology, it is possible to design and fabricate performance-competitive TV-sized AMOLED displays. In this paper, the system design considerations are described that lead to the selection of the device architecture (including a stacked white OLED-emitting unit), the backplane technology [an amorphous Si (a-Si) backplane with compensation for TFT degradation], and module design (for long life and low cost). The resulting AMOLED displays will meet performance and lifetime requirements, and will be manufacturing cost-competitive for TV applications. A high-performance 14-in. AMOLED display was fabricated by using an in-line OLED deposition machine to demonstrate some of these approaches. The chosen OLED technologies are scalable to larger glass substrate sizes compatible with existing a-Si backplane fabs.

P-138 Systems-Level Comparison of Singlet- and Triplet-Based Full-Color AM-OLED Displays for Power, Lifetime, and Color Gamut

In this paper, we compare the performance of full-color AM-OLED displays fabricated from singlet- and triplet-based materials. A systems-level approach was used to evaluate material performance, in terms of contribution to display power consumption, lifetime, and color gamut. Display architecture techniques were evaluated, such as microcavities and color filters, to enhance the performance of the display. Materials used for the evaluation included high-performance OLED materials from Kodak and published results from other OLED material manufacturers.

P-155: Ambient Contrast for OLED Displays

OLED devices typically include a back electrode that reflects both emitted and incident ambient light. The reflected ambient light reduces the contrast ratio of OLED displays, reducing the visibility and image quality of the display. A variety of techniques for improving OLED ambient contrast are described and measurements of their effectiveness are discussed together with any impact on other OLED performance characteristics.

P-34: Image Quality Impact of Pixel Patterns and Image Processing Algorithms for RGBW OLED Displays

Several RGBW pixel patterns were simulated with different RGB to RGBW color conversion approaches, and the resulting image quality was quantifiably compared to RGB pixel patterns. The image quality of select RGBW pixel patterns was found to be comparable or slightly higher than traditional RGB pixel patterns having the same number of pixels.

P‐73: Determining Power Consumption for Emissive Displays

Power consumption of an emissive display is directly influenced by image content. Therefore, when measuring display power consumption, it is important to select test targets that appropriately represent content that will be displayed within the application for which the display is intended. A model of display power consumption is used to understand the accuracy of various test targets for estimating average display power consumption for a defined application and to propose a technology-independent, but application-specific, method for measuring the average power consumption of a display.

62.3: Exploiting the Flexibility of RGBW OLED Displays: Trading Color Saturation for Power

The RGBW pixel pattern uniquely enables the tradeoff of color gamut for power consumption. A mechanism for achieving these tradeoffs and its application for reducing power consumption by more than 25% for typical images and 10% for typical web pages is discussed.

27.3: When is Sub‐Sampling in RGB Displays Practical?

The availability of more precise patterning continues to enable flat panel displays with higher resolution and addressability. As resolution increases, it becomes increasingly difficult for users to perceive individual light-emitting elements within a pixel. This paper explores the impact of several arrangements of light-emitting elements having fewer red and blue than green light-emitting elements on image quality, including displays providing two-color emission from spatially coincident areas.