A novel display device with dual emissive and reflective display mode (dual-mode display) was demonstrated. The novel device was based on electrochromic reaction as reflective mode and photoluminescence as emissive mode. An electrochromic molecule of viologen derivative and an luminescent lanthanide (III) complex were introduced for achieving dual-mode representation. The device functioned as an electrochromic device when bias voltage was applied and as a light-emitting device if excitation lights are irradiated. When bias voltage was applied to the device, cell color was changed from clear transparent to cyan color by electrochromic reaction of the viologen derivatives. On the other hand, under UV irradiation, strong red emission was observed from the lanthanide (III) complex. The emission intensity could be controlled by electrochromic reaction of viologen derivatives.
People tend to feel difficulty in working on displays rather than on paper. We suppose that rather long memory holding time, in our short-term memory, requested by working on a display is a dominant reason of difficulty with complicated tasks on a display. That's because working on a display, on which we often have to watch multi sheet of documents alternatively, generally force us longer memory holding time than when we are working on multi sheet of real papers. Subjects were requested to process tasks which need cross-reference between multi pages of documents with different viewing conditions of the pages;parallel showing and alternate showing of the multi pages. The results of measurement showed longer working time in alternate showing. We regard the longer working time in the alternate showing as a result of shortage of short-term memory, which was more eagerly requested by the alternate showing conditions.
In this paper we demonstrate the scalability of electrowetting display technology by presenting 8.5” diagonal active matrix displays. The rapid increase of the maximum display size of the electrowetting technology in the last year is a clear demonstration of its scalability. This scalability is enabled by a large degree of overlap in manufacturing technologies with the LCD manufacturing process. In addition, the grey scales on these displays are generated by analog driving, which ensures low power consumption also at large display sizes. The prototypes presented illustrate a good uniformity across the display.
The Digital Micro Shutter (DMSTM) Technology developed by Pixtronix not only provides low power direct view displays with exceptional image quality but also provides ultra low power E-paper compatible modes. Based on MEMS micro-shutters formed on active TFT backplanes, DMSTM technology has enabled the development of color sequential, time division gray scale, direct-view displays achieving breakthrough performance all at 1/4 the power consumption of comparable TFT-LCD and OLED display modules. Its exceptional image quality is due to its optical architecture and device mechanism. In addition, DMSTM display also presents excellent sunlight readability in transflective color and monochrome reflective modes. This readability can be attributed to reflective properties of the DMSTM optical architecture. This reflective nature also enhances viewing characteristics of transmissive color modes in high ambient lighting conditions. This paper will briefly describe the Pixtronix DMSTM display technology, its key architecture elements responsible for superior performance and comparison of display in reflective and transflective modes under high ambient lighting conditions. This paper will also describe the unique advantages of this technology in direct view display applications including programmability and low temperature operation.
We have developed a flexible full-color 4.1-inch 121-ppi FWQVGA AM-OLED display and a flexible 4.8-inch 169-dpi VGA electrophoretic display (EPD) driven by organic TFTs (OTFTs). In the OTFTs, all dielectric layers are formed from solution of polymers. For organic semiconductors, peri-Xanthenoxanthene (PXX) derivatives have been originally developed. The OTFT with 5-μm channel length shows apparent mobility of 0.4cm2/Vs and current on/off ratio >106. We have developed an integrated gate-driver circuit with the OTFTs on the flexible OLED display. This enables to eliminate rigid gate-driver ICs and roll up the OLED display with bending radius of 4mm. We have also developed high resolution printing technique of the PXX derivatives. The printed OTFT backplane has successfully applied to the flexible EPD.
We have developed a high resolution printing method based on offset printing, which enables high resolution printing on a large area using silver nanoparticle ink. A thin-film-transistor (TFT) with a short channel length below 10μm was successfully obtained. Furthermore, we have successfully fabricated 11 inch diagonal organic TFT arrays with high precision entirely by printing processes. The fully-printed organic TFT exhibited the mobility and on/off ratio of 0.4cm2/Vs and 1.1×109, respectively. We also discuss the uniformity of 300 transistors within 2 inch diagonal area. Electrical characteristics of the TFTs were investigated in detail. These technologies have been successfully applied to demonstrate an 11 inch VGA flexible active-matrix display driven by a printed organic TFT backplane.
It is recognized that reflective displays will play an increasingly important role in future information devices, principally due to their readability under high ambient light conditions and their lower power consumption. Monochrome electrophoretic displays (EPD) already satisfy some aspects of this requirement. However, to extend this to bright and vivid colour will require developments beyond the use of a colour filter array over a black and white electrophoretic electro-optical layer. Saturated colour particles, optionally in combination with highly reflective white particles are required for creating fluids to realize colour-filter-free, full colour electrophoretic displays. The use of improved, dyed polymeric microparticles with tuneable size, charge and colour, together with white reflective composite particles as a full colour EPD media is demonstrated.
80ppi, 160ppi and 200ppi all-printed organic thin film transistor (OTFT) backplanes were fabricated by a surface energy controlled ink-jet printing and several printing methods on plastic substrate. We developed the surface energy controlled ink-jet printing with ultraviolet (UV) irradiation on a novel polyimide film for high-resolution electrode patterning. Minimum line width was 15μm and minimum space between two electrodes was 2μm respectively. A 200ppi all-printed OTFT backplane with a channel length of 5μm showed high mobility over 0.1cm2/Vs with small-molecule organic semiconductor (OSC). To show the scaling capability, we have also fabricated a 300ppi all-printed OTFT array on plastic substrate. Flexible electrophoretic displays (EPDs) driven by 80ppi, 160ppi and 200ppi all-printed OTFT backplanes were also successfully demonstrated.
A novel electronic paper technology;Quick Response-Liquid Powder Display (QR-LPD) has been developed. This panel is operated by a new material which behaves just like liquid despite powder form. This electronic paper has the advantages of outstanding image stability, easy viewing, low-power consumption and a high-response time. We have successfully developed thin and light weight flexible electronic paper using QR-LPD technology. Furthermore, we have proved there is the great potential to utilize printable technology for an electronic paper. Direct formation of line-shaped electrodes consisting of transparent conductive polymer of poly (3, 4-ethylene dioxythiophene) and poly (styrenesulfonate)(PEDOT/PSS) was successfully achieved onto a flexible polyethylene terephthalate (PET) substrate by using screen printing method.
Thermal rewritable marking media are now attracting attention because of their low environmental impact and advanced functionality. These media can be divided into two types : media rewritable by a physical mechanism and those rewritable by a chemical mechanism. In Japan, thermal rewritable marking media are now used to store and display information on point cards in consumer loyalty programs. The market for these rewritable marking media is expected to expand with the introduction of new full-color recording material and laser marking technology.