| Architectures for enhancing reflective, bi-stable magneto-optical displays -> Monitor Keywords |
|
|
  Architectures for enhancing reflective, bi-stable magneto-optical displaysUSPTO Application #: 20080074368Title: Architectures for enhancing reflective, bi-stable magneto-optical displays Abstract: Magneto-optical displays offer numerous advantages in a multitude of applications, most notably large format signage applications. New designs and architectures such as the use of optical fluids, segmented magneto-optical element densities, frontplane lenses and color filters significantly expand the utility of these displays. (end of abstract)
Inventors: USPTO Applicaton #: 20080074368 - Class: 345 87 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20080074368. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001]This application claims the benefit of and priority to U.S. Provisional Application No. 60/847,601, filed Sep. 27, 2006, U.S. Provisional Application No. 60/847,603, filed Sep. 27, 2006 and U.S. Provisional Application No. 60/875,514, filed Dec. 18, 2006, all of which are incorporated herein by reference in their entirety. BACKGROUND OF THE INVENTION [0002]1. The Field of the Invention [0003]Embodiments of the present invention relate to improvements in the design of reflective bi-stable magneto-optical displays. Such displays are suitable for a multitude of applications especially low-cost, large-format information displays and outdoor signage applications. [0004]2. The Relevant Technology [0005]Traditional flat panel display technologies like plasma, liquid crystal and organic light emitting diode displays have proven unsuccessful for use in large format signage applications. These display technologies do not offer sufficient brightness and contrast when exposed to direct sunlight. In addition they are not cost effective or reliable when put in large format, outdoor environments. Today, large panel arrays of discrete light emitting diodes (LEDs) have been developed to fill the need of the digital signage market. These indoor and outdoor digital signage devices are very expensive products with a high number of discrete components and high power requirements. They must use a high number of densely packed high-brightness LEDs to emit enough light to compete directly with sunlight in outdoor and high brightness applications. Direct sunlight can be up to 100,000 lux. A simple one color, 4 line.times.20 character LED display will typically use approximately 2,800 discrete LEDs. An LED "Jumbotron" large format, color video screen may require more than 1 million discrete components. [0006]Additional features the sign industry is looking for are reflective technology in place of light emitting. In this scenario, direct sunlight is used during the day for illumination. At night, illumination requirements are far lower so the power used by a reflective display even with night lighting will be much lower. A reflective bistable display (a display that keeps the image without continuous power) can be very low power and effective for signs. This is because many signs will not required information to be changed frequently. A gas price sign may only be updated once a day. A clock only changes one digit every 60 seconds. Bistable displays can be ultra-low power making it possible for them to be powered by small batteries or solar cells. This would eliminate the need for costly wiring especially where the sign may not be near utilities. Finally light weight and thin digital signs are desirable because they reduce the cost of installation and the support structure required. The invention described herein has all of these features: reflective, bistable, low power, thin and light. [0007]Prior to LED signs, starting in the early 1900s, there were various electronic signage technologies that used electromagnetic actuators (Naylor U.S. Pat. No. 1,191,023, Taylor U.S. Pat. No. 3,140,553 and Browne U.S. Pat. No. 4,577,427). These discrete actuators were generally variations of small electromagnetic coils or motors with a reflective mechanical flap apparatus. They were broadly used and a small number of these device are still in use today for specific outdoor signage applications like score boards and transit signs however, they have become obsolete with the advent of LEDs because they were very expensive to construct, suffer from reliability issues and are limited in resolution due to the size of the discrete mechanical assemblies needed for each pixel. [0008]Development continued in the use of magnetic actuators for displays by Weiacht (U.S. Pat. No. 6,510,632) where magnets were attached to large flaps or "flags" that could be rotated 180 degrees in forming a signage character. This type of technology was continued with the patents of Fischer et al and others (U.S. Pat. No. 6,603,458, U.S. Pat. No. 3,936,818) again discussing the use of magnetically driven flaps as individual display pixels. These devices are mounted on a mechanical axis and only one magneto-optic "flag" is used in each individual device. [0009]While magnetics itself and the study of magnetic materials is an old discipline that dates back centuries and is still studied heavily today (Spaldin, N., Magnetic Materials: Fundamentals and Device Applications, Cambridge Univ. Press, 2003; Kittel, C. Introduction to Solid State Physics, Wiley, 1996), few attempts have been made to develop reflective magnetic-based display technology. In 1898 and 1928 Poulsen and Pfleumer, respectively, leveraging magnetic phenomena, developed the use of magnetics in recording media. In the 1960's magnetic materials were used to store memory, first by Forrester et al and others (U.S. Pat. No. 2,736,880, U.S. Pat. No. 2,667,542, U.S. Pat. No. 2,708,722). Magnetic core memory, pioneered by Olsen and others (U.S. Pat. No. 3,161,861, U.S. Pat. No. 4,161,037, U.S. Pat. No. 4,464,752) has seen significant attention for decades due to its implications on the computing industry but for a number of reasons was replaced by silicon-based memory devices. The only work in the use of magnetics in displays outside of the older "flap" technologies utilize bi-colored magnetic particles instead of mechanical flaps. Here, the use of smaller discrete magnetic spheres has been envisioned as a display design by Magnavox (Lee, L. IEEE Transactions on Electron Devices, ED-22, P758) and more recently by Katsuragawa et al. (Japan Patent Publication 2002-006346) and to a lesser extent by Masatori (Japan Patent Publication 08-197891). This prior art deals primarily with the use of small magnetic particles which respond to external magnetic field by rotating. The rotation of these magnetic particles is in response to the external field and the particles desire to lower their potential energy. Here, the magnetic spheres are magnetized along the center axis. The north and south poles of the spheres are coated with different colors. A magnetic field is then applied that rotates the particles between the two color states. This method of making an electromagnetic display has several problems which will now be discussed. [0010]A first problem is an external magnetic field needs to be sustained. Without an ongoing electromagnetic field, the particles will align to each other in a low energy, grey state. Two methods to sustain the magnetic field are: 1) Use constant current to the electromagnetic coil--the issue here is constant power consumption and it requires much higher cost control electronics. 2) Add a layer of ferrite/"writable" magnetic material. This layer must sustain a sufficient magnetic field after it has been "written" by an electromagnetic write pulse. One issue here is that the added layer is a complex magnetic material that needs to be developed. Also the strength of the magnetic field and stability of the "writable" magnetic state is complex. There is significant added cost of manufacturing with this more complex structure. Finally, the energy required to create a sufficient B magnetic field inside the material to "write" a sustainable magnetic state can be considerable. [0011]A second problem is crosstalk between pixels. The flux patterns created by two pixels of different states will create curved flux lines between their poles. The transition from one pixel's color state (North) to the second pixel's color state (South) will create flux patterns that are displayed as artifacts between pixels that will be viewed as a "grey" zone. Creating distinct separation between pixels without crosstalk is a major problem. Another form of crosstalk can occur when the magnetic field of one pixel "overpowers" a neighboring pixel and reverse its state during the write process. [0012]A third problem is low contrast. Spherical particles, if placed in a single layer, will have limited contrast because they do not have full coverage of the display plane. If multiple layers of magnetic spheres are used, this increases their interference with each other, making it more difficult to control their states and thus requiring a stronger external magnetic field. [0013]A fourth problem is magnetic materials. Development of new materials of construction and methods of fabrication are needed. The materials and methods must create low cost, light weight, environmentally stable, permanent magneto optical elements with accurate alignment of the magnetic field to the color planes. [0014]A fifth problem is resolution limitations. This is because the domains of permanent magnetic particles lose stability when they are isolated or particles are made too small (for example, below 100 microns a drop in stability in magnetic particles starts to be observed depending on the specific material). In addition, electromagnetic coil assemblies become less efficient when the size is below 1 mm due to heat losses in the wire windings from the increased resistance of the smaller conductors. Also, in order for low cost, industrial manufacturing processes to replace high cost "clean room" processes, the manufacturing tolerances need to be in the range of .+-.25 microns or larger to enable ease of manufacturing. [0015]A sixth problem is design of a low cost electronic backplane. The highest cost processes in flat panel displays is the manufacturing of active matrix backplane layers that control the display. Most liquid crystal (LCD), organic light emitting diode (OLED) and even the latest electronic-paper (ePaper) displays utilize an array of thin film transistors (TFTs) that are manufactured over the entire back of the display to control the image. The cost of this backplane can equal 50% of the entire process costs of the display panel. A low cost backplane alternative is needed for large format signage applications. BRIEF SUMMARY [0016]A first embodiment disclosed herein relates to a magneto-optical display. The display includes a plurality of magneto-optical display elements, a cavity configured to house the plurality of magneto-optical display elements and permit rotation of the plurality of magneto-optical display elements, and an optical carrier fluid disposed within the cavity, wherein the plurality of magneto-optical display elements are placed in the optical carrier fluid. The plurality of magneto-optical display elements include a magnetic component, two colored surfaces that are configured to be rotated into a first and second viewable state, a top portion configured to have a density that is less than the optical carrier fluid, such that the top portion is buoyant; and a bottom portion that has a density greater than the density of the optical carrier fluid, such that the bottom portion is non-buoyant. [0017]A second embodiment disclosed herein relate to a magneto-optical display. The display includes a plurality of reflective bi-stable magneto-optical display elements configured to change from a first viewable color to a second viewable color, the plurality of magneto-optical display elements defining at least a portion of one or more display portions that changes color, one or more display portions that do not change color or that include a shadow, and a front panel including one or more optical elements configured to redirect light from the one or more display portions that do not change colors or include a shadow to the one or more display portions that do change color. [0018]A third embodiment disclosed herein relate to a magneto-optical display. The display includes a plurality of reflective bi-stable magneto-optical display elements configured to change from a first viewable color to a second viewable color, a frontplane disposed in front of the plurality of magneto-optical display elements, and one or more light sources placed at one or more edges of the frontplane, wherein the frontplane is configured to direct light generated by the one or more light sources towards the plurality of magneto-optical display elements. [0019]A fourth embodiment disclosed herein relate to a magneto-optical display. The display includes a plurality of reflective bi-stable magneto-optical display elements configured to change from a first viewable color to a second viewable color, wherein the first color is a color configured to at least partially reflect light and the second color is a color configured to at least partially absorb light, a frontplane disposed in front of the plurality of magneto-optical display elements, and one or more color filters placed between the plurality of magneto-optical display elements and an observer of the display, wherein the one more color filters are of a different color than the first and second colors. [0020]A fifth embodiment disclosed herein relate to a magneto-optical display. The display includes a plurality of reflective bi-stable magneto-optical display elements configured to change from a first viewable color to a second viewable color, frontplane disposed in front of the plurality of magneto-optical display elements, and one or more graphics placed between the plurality of magneto-optical display elements and an observer of the display, wherein changing from the first viewable color to the second viewable color causes the one or more graphics to change from a third viewable color to a fourth viewable color. [0021]A sixth embodiment disclosed herein relate to a magneto-optical display. The display includes a plurality of magneto-optical display elements configured as one or more pixels, wherein the one or more pixels are configured in a full Red, Green and Blue (RGB) display, and wherein the one or more pixels are configured to be selectively activated when subjected to a magnetic field such that the activated pixels generate a plurality of color combinations viewable in the magneto-optical display. Continue reading... Full patent description for Architectures for enhancing reflective, bi-stable magneto-optical displays Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Architectures for enhancing reflective, bi-stable magneto-optical displays patent application. Patent Applications in related categories: 20080246709 - Display device - A display device which includes a display panel with plural sub-pixels, first and second conversion circuits for converting the display data in the intermediate gradation input from the external system into different values, a driver which outputs the video voltage corresponding to the display data to the sub-pixels, and a ... 20080246710 - Display device and driving method thereof - A display device includes an active-matrix-type display panel including video signal lines, and a video signal lines driving circuit which supplies display data to the video signal lines, and a display control circuit receiving video data from an external signal source, and outputting the display data to the video signal ... 20080246708 - Liquid crystal device, image sensor, and electronic apparatus - The invention provides a liquid crystal device including: a first substrate; a second substrate that is provided over the first substrate in such a manner that the first substrate and the second substrate face each other; a plurality of optical sensing sections that is formed in an image display area ... 20080246711 - Using packet transfer for driving lcd panel driver electronics - In a digital display device, a packet based method of driving selected pixel elements by way of associated data latches included in a column driver is disclosed. For each frame lines in a video frame, a number of video data packets are provided directly to the column driver at a ... ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Architectures for enhancing reflective, bi-stable magneto-optical displays or other areas of interest. ### Previous Patent Application: Reflective, bi-stable magneto optical display architectures Next Patent Application: Cross-talk correction for a liquid crystal display Industry Class: Computer graphics processing, operator interface processing, and selective visual display systems ### FreshPatents.com Support Thank you for viewing the Architectures for enhancing reflective, bi-stable magneto-optical displays patent info. IP-related news and info Results in 2.65334 seconds Other interesting Feshpatents.com categories: Qualcomm , Schering-Plough , Schlumberger , Seagate , Siemens , Texas Instruments , |
||
