Quick-Response Liquid Powder Display Research Articles

Constrained non-negative matrix factorization for multiline addressing schemes of quick-response liquid powder display

A quick-response liquid powder display (QR-LPD) is a favorable candidate for flexible electronic papers because it can be simply operated by passive-matrix driving. However, the slow image refreshing rate is its major problem. In this study, multiline addressing (MLA) schemes for QR-LPD have been developed for improving the driving efficiency. Non-negative matrix factorization (NMF) with boundary constraints is used for the MLA scheme. A hybrid pulse modulation (HPM) is proposed for further shortening the driving waveform. The experimental results reveal that the MLA using NMF produces a noisy image on QR-LPD. The root cause for this is that NMF is a linear factorization but the electro-optical response of QR-LPD is not a linear curve. Therefore, we have proposed a lossless matrix factorization (LMF) method. The MLA scheme using LMF not only improves the image refreshing rate but also shows images without loss.

Color Realization of Reflective Electronic Display Using Particle-Moving Method

We propose a color realization method of a reflective display based on quick response-liquid powder display (QR-LPD). We use the particle-moving method in order to address the color particles cyan, magenta, yellow, and black (CMYK) into their respective cells. We fabricated a color addressed reflective display panel using indium-tin-oxide (ITO) glass with a rib width of 15 μm, a cell size of 300 μm × 300 μm, an average particle diameter of 8 μm, and a particle charge to mass ratio (q/m) from +8.5 μC/g to -4 μC/g. Most particles are inserted into their cells on the upper substrate, with non-movable particles removed in a previous step. The fabricated color panel shows a well-addressed CMYK array in microscopic photographs. An additional color display is fabricated using line-by-line addressing in order to facilitate the addressing process.

An Analysis of Particle-clumping Phenomena of a Charged Particle-type Reflective Electronic Display

Both the electrically positive and negative particles in a cell of quick response-liquid powder display (QR-LPD) are surrounded by conductive electrodes on the upper and lower substrate and the dielectric materials of the barrier ribs. Particles in a cell are attached to or detached from the other materials by image force, electric field, Coulomb's force, and Van der Waals' force. Through these forces, the moving particles form an image but induce clumping phenomena. Particles having a large kinetic energy by a large q/m value crash into the opposite electrode with high speed at a large driving voltage and quickly lose electrically charged material. As a result, these particles are clumped and degrade panel performance. The clumped particles in a cell are observed by microscopic photographs and ascertained by a response time. When the bias voltage is increased to 0.68-0.76 <TEX>$V/{\mu}m$</TEX>, particle clumping occurs abruptly and the response time increases sharply. This particle clumping is similarly observed after the number of driving times at the driving voltage (0.42-0.64 <TEX>$V/{\mu}m$</TEX>).

Improvement of Electric and Optical Properties of a Reflective Electronic Display by Particle-Moving Method

We propose a new particle-insertion method for a reflective display based on the structure of a quick response-liquid powder display (QR-LPD). To compare this method with the reported simple loading method, two panels are fabricated in the same panel condition of which the width of ribs is 30 μm, the cell size is 220 μm 220 μm, the cell gap is 116-120 μm, the m value of the black particles is μC/g and that for the white particles is μC/g. This method excludes the non-moving particles, inserting only mobile particles into a substrate by using electric fields so that a panel fabricated by the particle-moving method can drive most of the particles in a cell. Also, most of the particles move at the threshold voltage of 40 V with enhanced reflectivity.

Active-Matrix Backplane with Inkjet Printed Organic Thin-Film Transistors (OTFTs) for QR-LPD

Active matrix organic-TFT(OTFT) array for Quick-Response Liquid Powder Display (QR-LPD) was fabricated by use of inkjet printing technology.To define the shape and size of patterns formed by inkjet printing, we adopted a novel surface modification technique called photocatalytic lithography. Photocatalyst such as TiO2 oxidizes various organic materials in an excited state. Therefore photomask with a photocatalytic layer, irradiated with ultraviolet (UV) light, can oxidize selectively the surface of the organic material layer facing the phtocatalytic and then form hydrophobic and hydrophilic patterns. Ink-droplets ejected from ink jet print head spread only on the hydrophilic area and set like the mask pattern.We have developed to apply this technique to fabricating flat panel display components such as color filter, biomedical tools, and so on. The combination of inkjet printing and photocatalytic lithography enables fine patterns to be formed in a few steps and at low cost.In this study, we obtained well-defined source and drain electrode in which the channel length is below 10 micron by use of inkjet and photocatalytic lithography. As a result, high contrast image consist of 10 inch, 80 dpi QR-LPD active matrix array was refreshed successfully.

A Flexible electronic‐paper display with an ultra‐thin and flexible LSI driver using quick‐response liquid‐powder technology

Abstract— A thin and flexible LSI driver with a thickness of less than 35 μm for a passive‐matrix‐driven Quick‐Response Liquid‐Powder Display (QR‐LPD™) was successfully mounted onto the flexible printed circuit (FPC) and the back substrates of a flexible QR‐LPD™. Amounted LSI driver on a plastic substrate shows no significant degradation in the driving performances and maintains physical flexibility without any connection failures. This technology can realize a fully flexible electronic paper in combination with a plastic‐substrate QR‐LPD™ fabricated by a roll‐to‐roll process.

Novel Type of Bistable Reflective Display (QR-LPD&amp;#xAE;) and Material Design of Electronic Liquid Powder&amp;#xAE;

A novel reflective display; Quick-Response Liquid Powder Display (QR-LPD&#xAE;), has been developed in this study. The new display shows the advantages of outstanding image stability, easy viewing, low-power consumption and a fast-response time. A highly fluidizing powder is used for producing paper like images. In this paper the material design of the powders for the display is described and the electrostatic features are discussed. Some of the recent products using QR-LPD&#xAE; will also be demonstrated.

37.3: Three-Voltage-Level Driver Driven Quick-Response Liquid Powder Display

We developed a new custom-made high voltage driver with three voltage levels and with low power consumption for Quick-Response Liquid Powder Display (QR-LPD), which allows a variety of driving method. The difference between the driving methods was investigated in terms of image quality and power consumption.

A quick‐response liquid‐powder display (QR‐LPD®) with plastic substrate

Abstract— Paper‐like displays as thin as 290 μm have been developed using QR‐LPD technology. We fabricated two types of displays. One is a dot‐matrix type with a 160 × 160 array of pixels and a 3.1‐in.‐diagonal viewable image size. The other is a segmented type for clock use. Each display has a paper‐like appearance and exhibits high contrast. Plastic substrates with a thickness of 120 μm were used, resulting in flexible displays that can be bent up to a radius of curvature of 20 mm.