US 20050134461 A1
The present invention provides for an electronic label associated with a transponder. The electronic label displays at least one graphical element to provide a visual indication representative of information associated with the transponder. Representable information can include a result of a communication with the transponder, a location of the transponder or an item associated with the transponder, a state of the transponder, or an item associated with the transponder, a status of the transponder or an item associated with the transponder, or any combination of information. The display of the graphical element can further indicate if a read operation has failed or has not yet taken place. The graphical element is alterable and updateable. The graphical element can indicate if the RFID tag is activate or has been deactivated allowing a consumer to readily determine the state of an RFID tag associated with a consumer item.
1. A method for marking an item, comprising the steps of:
detecting the item at a location; and
displaying a visual indicator on an electronic label associated with the item in response to detection of the item;
wherein said electronic label comprises an electronic display.
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monitoring a plurality of locations to detect a change in location of the item, and
in response to a detection of the change in location of the item, displaying information on the electronic label.
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wherein the electronic label comprises a segmented electronic display having at least one segment.
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28. A method for indicating a state of an item, comprising the steps of:
detecting the state of the item; and
displaying a visual indicator on an electronic label associated with the item in response to detection of the state of the item,
wherein said electronic label comprises an electronic display.
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51. A system for electronically providing visual indications about an item, said system comprising:
a transceiver module capable of communicating with an electronic label associated with the item in a communications protocol, wherein the electronic label comprises
an interface mechanism for communicating with the transceiver module; and
a display medium for displaying a visual indicator, wherein said visual indicator represents at least one of a successful communication with the transceiver module, an unsuccessful communication with the transceiver module, and no communication with the transceiver module.
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84. A method for marking an item, comprising the steps of:
detecting a state of the item; and
displaying a visual indicator on an electronic label associated with the item in response to detection of said state of the item,
wherein said electronic label comprises an electronic display.
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89. A method for tracking an item, comprising the steps of:
detecting a status of the item; and
displaying a visual indicator on an electronic label associated with the item in response to detection of said status of the item,
wherein said electronic label comprises an electronic display.
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94. A method for tracking an item, comprising the steps of:
detecting information related to the item; and
displaying a visual indicator on an electronic label associated with the item in response to detection of said information related to the item,
wherein said electronic label comprises an electronic display.
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This application claims priority to provisional patent application Ser. No. 60/499,334, filed Sep. 3, 2003, the contents of which are hereby incorporated by reference.
The present invention is directed to electronic labels and display devices. More particularly, the present invention is directed to the tracking of changes in state, changes in location or changes in information related to an item associated with an electronic label.
The use of Radio Frequency Identification (RFID) tags are quickly gaining popularity for use in the monitoring and tracking of an item. RFID technology allows a user to remotely store and retrieve data in connection with an item utilizing a small, unobtrusive tag. As a RFID tag operates in the radio frequency (RF) portion of the electromagnetic spectrum, an electromagnetic or electrostatic coupling can occur between a RFID tag affixed to an item and a RFID tag reader. This coupling is advantageous, as it precludes the need for a direct contact or line of sight connection between the tag and the reader. A RFID tag may additionally incorporate an Electronic Product Code (EPC) number that serves to identify a specific item with a unique code. Additionally, a RFID tag may also include various storage means which allow for the storage of information related to the item to which the tag is affixed. Furthermore, data relating to an item can be stored in one or more databases linked to the RFID tag. These databases do not reside on the tag, but rather are linked to the tag through a unique identifier(s) or reference key(s).
Utilizing a RFID tag, an item may be tagged at a period when the initial properties of the item are known. For example, this first tagging of the item may correspond with the beginning of the manufacturing process, or may occur as an item is first packaged for delivery. Electronically tagging the item allows for subsequent electronic exchanges of information between the tagged item and a user, wherein a user may read information stored within the tag and may additionally write information to the tag. While such an arrangement is beneficial, several notable drawbacks exist.
First, following a communication with a tag, a user has no readily available indication if the communication was successful. In an assembly line setting, for example, it is difficult to determine if each item passing a tag reader is read successfully. Furthermore, should one become aware that at least one item was not read, it is time consuming and difficult to pinpoint which item failed to be read successfully. To ensure inventory accuracy in such a situation it may become necessary to reprocess a large number of items a second time in order to account for the missing item. Additionally, when scanning a number of tagged items that are all in close proximity to each other, it is oftentimes burdensome to determine which item tag a user is actually reading.
RFID tags may be employed in both manual and automatic scanning environments. An example of an automatic scanning environment is a conveyor belt with numerous tagged items passing a tag reader. A manual scanning environment, in contrast, is exhibited by a user utilizing a handheld tag reader to query individual packages within a warehouse. When employed in a manual scanning environment, existing RFID techniques require the user to look at a display external to the tag to view information. The display can be an integral part of a handheld manual reader or may be indirectly connected to the reader using various means such as a corded connection or wireless link. The reader may also take the form of a standalone computer system that displays RFID tag information on a computer monitor. Utilizing such an arrangement, a user is burdened by having to look at a computer screen or paper printout in order to try and understand what is transpiring electronically. In light of this, a user's attention is diverted away from the item. Such a diversion is clearly inefficient and may be potentially dangerous.
Additionally, as RFID technology has been implemented on a large global scale, active and passive RFID tags are being embedded within a high percentage of consumer and commercial items. These tags may be active or passive in nature and may communicate on various wavelengths within the electromagnetic spectrum. Active RFID tags are powered by an internal battery and typically support read from the tag, writing to the tag or a combination of both. Passive RFID tags operate without a separate external power source and generate operating power upon communication with the reader. In comparison to active tags, passive tags are much lighter, less expensive, and offer a virtually unlimited operational lifetime. Passive RFID tags typically only support reading information from the tag.
Both active and passive RFID tag may operate within various regions of the radio frequency spectrum. Low-frequency (30 KHz to 500 KHz) tags have low system costs and are limited to short reading ranges. Low frequency tags are commonly used in security access and animal identification applications. High-frequency (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) tags offer increased read ranges and high reading speeds. One common application of high frequency tags is automated toll collection on highways and interstates.
The long life and continuous operation of RFID tags, coupled with the distances at which a tag may be read, has caused considerable controversy regarding privacy concerns. A purchaser of a tagged item may pay for a product, leave the store, yet the embedded tag remains activate. An active tag can then be continually read from a distance without the knowledge or consent of the purchaser. Additionally, if the tagged item was purchased using a credit card or debit card, it is possible to associate the unique ID of the tag to the identity of the purchaser. An association such as this essentially allows tracking of individuals based upon tagged items that they have purchased.
The present invention provides for an electronic label associated with a transponder. The electronic label displays at least one graphical element to provide a visual indication representative of information associated with the transponder. Information associated with the transponder represent able by the graphical element can include a result of a communication with the transponder, a location of the transponder, a location of an item associated with the transponder, a state of the transponder, a state of an item associated with the transponder, a status of the transponder, a status of an item associated with the transponder, or any combination of information. For example, the display of the visual graphical element can indicate a read operation occurred between the transponder and electronic label. Likewise, the display of the visual graphical element can indicate read operation has failed or has not yet taken place between the transponder and electronic label. The graphical element is alterable and updateable, such that a varying status of the transducer, transponder, or an item associated with the transducer, transponder, or electronic label can be communicated to a user in a visual graphical manner. As such, the graphical element displayed by the associated electronic label can indicate if the RFID tag is activate or has been deactivated. Hence, in light of the inherent privacy concerns with the use of RFID tags with consumer items, the present invention provides a method and a system that allows a consumer to readily determine the state of an RFID tag associated with a consumer item through the use of a visual indicator.
The present invention further provides for an electronic label that displays a graphical indication to a user that serves to indicate a location, a state, a status, or any combination thereof of an item associated with the electronic label. This graphical indication is alterable and updateable, such that a varying status of the label can be communicated to a user in a graphical manner. Furthermore, this graphical indicator can be used to represent the status of the item associated with the electronic label.
In one illustrative embodiment of the present invention a method for visually tracking an item is disclosed. Performance of the method provides for the location of an item to be represented by visual indicators on the electronic display of the electronic label associated with the item. The display of this visual indicator is in response to the location, or change of location of the item. Performance of the method can further monitor the item at a plurality of locations to assist in detecting the item as it arrives, departs, or moves around within a location. Further, a plurality of locations may be monitored such that the location of an item may be determined.
The method can further include a step of providing an electronic display, associated with the item that is flexible in nature and capable of moving in a plurality of directions. In one aspect of the present invention, the electronic display may be capable of conforming to the surface topology of an item on which the electronic label is placed.
The method can further include the steps for providing an electronic display with a plurality of regions wherein a plurality of visual indicators may be displayed to indicate a plurality of changes in state or the current state of the item. These indicators can provide an indication in human readable form, a graphical form, a machine readable form or any combination thereof. Human readable forms can include alphanumeric characters, and graphical forms may include shapes, icons or changes in color. Machine readable forms can include barcodes or matrix code symbologies. Matrix code symbologies are not comprised of stacked rows, common to a traditional barcode, but of a matrix array made up of hexagonal, square, polygonal and/or other geometric shapes, lines, or dots. Such symbols are described in, for example, U.S. Pat. Nos. 5,2276,315 and 4,794,239 which are incorporated herein by reference. Such matrix code symbologies may include Vericode, Datacode, and Maxicode. Such matrix array symbologies are currently utilized by numerous parcel delivery services, including the United Parcel Service (UPS).
In one embodiment of the present invention, the electronic display may be constructed of at least a display medium and a backplane. The method can further include steps to display a visual indicator that remains illuminated for a period of time following the removal of power to the display medium. This time period may be a function of the material properties selected for the display medium, a function of the environment in which the display is operating, or may be a controlled by hardware, firmware, software or any combination thereof. In one aspect of the present invention, the electronic display can be sized to cover the entire surface occupied by the electronic label. In another aspect of the present invention, the electronic display can be sized to occupy only a portion of the electronic label.
In another illustrative embodiment of the present invention, a method for indicating the state of an item is disclosed. The current state or a change in state of the item is first detected or determined, wherein this change in state can be detected by monitoring the state of the item. For example, the state or change in state can be detected or determined by monitoring the state of the item using a sensor associated with the electronic label to detect a change in state of the item or the environment in which it is located. After the current state, or a change in state is detected, a visual indicator is displayed on the electronic label associated with the item, wherein the visual indicator indicates the current state or a change in state. In another aspect of the present invention, the state can be defined as read or unread or activated or deactivated. The state of the item can further be defined as having successfully or unsuccessfully received or transmitted information relating to an external database over a wireless link. Furthermore, the method of the present invention can include the step of providing a plurality of visual indicators on an electronic display such that a plurality of state changes can be graphically displayed individually or in a near simultaneous manner. The display of visual indicators can be in a machine readable format or can be in a human readable format. The method can further include the step of powering the electronic display with either an internal or external power source. The method can further include the step of powering the electronic display with a signal having a data component and a power component. Examples of mechanisms for powering an electronic label or RFID tag using a signal having both a power and data component are set forth in U.S. Pat. No. 5,583,819 and U.S. Pat. No. 5,945,920, the contents of which are herein incorporated by reference.
Moreover, upon removal of power to the entire electronic label, or a selected component of the electronic label, the display may continue to provide a visual indicator for a period of time. This time period may be a function of the material properties of those materials used in the electronic display or may be controlled by the electronic label. In one illustrate embodiment of the present invention, the electronic display may further be sized to occupy the entire region occupied by the electronic label. The electronic display can also be sized to occupy only a region of the electronic label. The electronic label, and the electronic display associated with the electronic label can further flex, thereby allowing for movement in a plurality of dimensions.
In another embodiment of the present invention, a system for electronically displaying state information of a tracked item is disclosed. This system includes an electronic label capable of displaying a visual indication of the state of a tracked item. The electronic label includes both a display medium and a mechanism for transferring state information of the tracked item to the label. The system further includes a transceiver module in communication with the electronic label. The transceiver module is capable of transmitting state information to the electronic label, using a communication protocol, either wired or wireless, to remotely update and permanently or temporarily alter the information displayed in human readable for, machine readable form, or both. This transmission can occur at a frequency within the electromagnetic spectrum, including but not limited to radio waves, light waves or microwaves.
The electronic label of the present invention can be flexible and capable of being formed in various shapes and sizes. The number of layers forming the device can vary depending upon the particular components employed in the device, and upon the requirements of the intended application. The electronic display associated with the electronic label can include a plurality of regions. Each region can be graphically display one or more visual indicators. The electronic display is capable of reproducing text and graphical images using segments, pixels or any combination thereof. The displayed visual indicator can be in a machine readable format, a human readable format, or a combination of both. The visual indicator can be reproduced in black and white, grayscale, color, or any combination thereof. Also the label can be used to present any vision based symbologies such as two dimension bar codes, three dimension coding schemes or any combination of graphical, alpha numeric, character, pixel or vision symbologies. Visual indicators presented on the electronic display may be turned on or off, or may be continuously updated and changed. For example, an initial bar code displayed on a pixel addressable display may be replaced with a second barcode to signify the change in status, state or location of an item.
It is a further object of the present invention to provide an electronic label wherein the electronic display continues to display information for a period of time after power is removed. The length of time that the label will continue to display information can be accurately controlled either by varying the attributes of the electronic display or through control hardware, software, or a combination of hardware and software. Furthermore, the time the image remains after power is removed can be a function of time or can be a function of varying parameters, such as the external environment in which the label is operating. Power for the label can be provided form either an internal means or an external means, including an on board battery source, a photovoltaic panel, an inductive or capacitance coupling or any combination thereof. For example, power supplied to the electronic label from an internal battery may be supplemented by power supplied to the electronic label by an external inductive coupling.
According to one practice, the electronic label can be updated utilizing wireless technology. For example radio waves, infrared waves, visible light, microwaves, or any combination thereof can be used. Furthermore, the electronic label can be incorporated into a mixed media label, wherein the electronic label is combined with traditional labels made of pulp or plastic material, onto which information is printed, using such mediums as color print advertisements or black and white barcodes to form a single label arrangement. This multimedia label can then be affixed to an item utilizing traditional means such as, but not limited to, adhesive backings, hook and loop fasteners, or mechanical hardware. In such an embodiment, the electronic label can be sized to cover the entire mixed media label, or can alternatively be sized to only cover a portion of the mixed media label. Furthermore, in one aspect, the electronic display associated with the electronic label can be a bi-stable non-volatile display. In an alternate aspect the electronic label can be volatile, thereby requiring an on board power source to maintain the visual indicator. In another aspect, the electronic label can be associated with an external sensor capable of providing state information of the item to be tracked.
The foregoing and other objects, features and advantages of the invention will be apparent from the following description and apparent from the accompanying drawings, in which like reference characters refer to the same parts throughout the different views. The drawings illustrate principles of the invention and, although not to scale, show relative dimensions.
The illustrative embodiment of the present invention provides a method and system for displaying a visual indicator on an electronic display associated with an item to indicate a state, a status or a location of the item. The method and system of the illustrative embodiment of the present invention allows a user to visually confirm the state, status and location of an item with which the electronic label is associated. Likewise, the visual indicator provided by the electronic label associated with the item allows a user to visually ascertain that a change has occurred with the item associated with the electronic display. The electronic display of the present invention may indicate the occurrence of a single location change, state change or a status change, or may indicate the occurrence of a number of state changes, location changes, or status changes of an item associated with the electronic display.
The transceiver module 12 can receive and transmit information concerning the item using a communication protocol. The term “communication protocol” as used herein refers to a format for transmitting data between two devices. The format defines any means by which a signal can be transmitted and can include wired means, wireless means or a combination of both. Wired means can include the use of electrical conductors or fiber optic conductors. Wireless signal transmission can occur using any region of the electromagnetic spectrum. For example the visible light, infrared, microwave, radio frequency, X-ray or gamma ray region of the electromagnetic spectrum can be utilized. An antenna 13A can be coupled to the transceiver module 12 for transmitting and receiving wireless signals. A power supply 15A for providing power to the transceiver module 12 can also be coupled with the transceiver module 12. The power supply 15A can be either internal to the transceiver module 12, or can be eternal to the transceiver module 12. For the purpose of illustration, the power supply 15A has been shown as external to the transceiver module 12.
The electronic label 14A can further contain an antenna 13B coupled with the interface module 16. This antenna 133B can be used to send, receive, or send and receive a wireless signal containing information of the item associated with the electronic label 14A. Those of ordinary skill will recognize that any number of suitable antennas can be employed in connection with the electronic label of the present invention. For example, the electronic label 14A can employ a common antenna perform all necessary functions, a discrete antenna for each function associated with the electronic label, or any subset of antennas for performing one or more functions. The wireless signal received by the antenna associated with the interface module 16 can contain a data signal, a power signal or a combination of both. A power signal can be used to provide power to the electronic label 14A. Absent a power signal, a power supply 15B can be coupled with electronic label 14A. This power supply 15B can be located internal to the electronic label or external to the electronic label. Additionally, the electronic label 14A can utilize more than one power supply means, wherein a second power supply 15B can be utilized in augmenting a primary power supply. For example, an electronic label 14A that receives power through a wireless power signal can further utilize an external power supply 15B to augment power provided to the label 14A.
The electronic label 14A further includes a Radio Frequency Identification (RFID) tag 19A. The RFID tag 19A can allow for the remote storage and retrieval of data in connection with the item associated with the label. The electronic label 14A can also be associated with an Electronic Product Code (EPC) module 19B. The EPC module 19B can provide a unique identifier associated with each tracked item in conjunction with the RFID tag 19A.
Furthermore, data relating to an item can be stored in one or more databases 17 linked to the RFID tag. These databases can reside on the electronic label 14, or can be linked to the electronic label 14 through a communication protocol such as an encrypted wireless link. For the purpose of clarity, the database 17 is shown remotely located from the electronic label 14A.
For the purpose of illustration, visual indicators displayed in the various regions are provided in plain text, but in practice the electronic label 14F can provide data on an electronic display in any number of formats including but not limited to machine readable barcodes and symbols, geometric shapes, or varying colors. For example, the visual indicator displayed on the electronic display 18 associated with the electronic label 14F may be a machine readable barcode or a matrix array symbology. Utilizing a barcode or matrix array symbology, detailed information can be presented in a machine readable format. The information can relate to past, present or future locations within the supply chain. In the alternative, the visual indicator may include both a human readable display as well as a machine readable display.
The visual indicator on the electronic display 18 can be used to display at least one of a past location, a present location or a future location of the item to be tracked. A future location of an item can be a new location or can be a return to a previous location. For example, an item can move from a shelf in a warehouse to an inventory control point within the same warehouse. This can be viewed as a move from a past to a present location. The item can then move from the present location, the inventory control point, to either a truck for delivery or can be return to the shelf in the warehouse. The move from the inventory control point to either the awaiting truck, or the shelf in the warehouse is a move from a present location to a future location. The present invention also provides a visual indication of current location of the electronic label attached to an item without the need for any knowledge of past or future locations relating to the item
In one embodiment information indicated on the various regions of the electronic display 18 associated with the electronic label 14F may remain for a fixed period of time upon the removal of power from the electronic display 18. This time period may be a function of the material properties of the electronic display 18, a function of the operating environment of the electronic display, or may be controlled by the interface module of the electronic label. Operating environment factors include, but are not limited to, temperature, humidity, pH, sun light, ultraviolet light, as well as the presence of various chemical compounds, radioactivity, pathogens, bacteria, viruses or pryons.
The visual indicator may additionally take numerous forms, and is not limited to the circular arrangement presented as an example. In one embodiment, a varying color change may be utilized to indicate a state change. In an alternate embodiment, numerous visual indicators may be associated with the electronic label 14G, wherein human readable or machine readable information is presented on each indicator. Furthermore, the electronic label 14G of the present invention may be sized such that it alone is the indicator of RFID tag state, or can be a portion of label 80 which combines a first media 82 and second media 14G. The first media 82 can be a non-alterable print advertisement, and the second media can be an electronic label in accordance with the present invention 14G.
The electronic label 14I can be attached to an item utilizing numerous means. For example, conventional mechanical fastening system, loop and hook-type arrangements, stitches, adhesives, as well as other known fixation techniques may be employed to permanently or temporarily attach the electronic label to an item. The electronic label 14I can also be integrally formed with the item, or can be used as a stand alone electronic label. As used herein, the term label is intended to include a label, strip, tag or general display device that is sufficiently sized and configured for attachment to an item. While the electronic display 18 associated with the electronic label 14I is shown as a plurality of layers in
Dispersed across the backplane 126 is a plurality of conductive traces 128, wherein these conductive traces 128 are oriented to activating a visual indicator on the display medium 124. The display medium 124 can be actuated utilizing numerous methods depending upon the intended visual indicator. The backplane 126 may employ direct drive icon activation, direct drive alpha numeric segment based character activation, row column addressable indicator activation, active matrix indicator activation, or a combination of the above to adequately display a visual indicator on the display medium 124. The aforementioned illumination means can be employed separately or in combination depending upon the intended visual indicator. For example, some indicators may require a direct line to illuminate the display medium, whereas other indicators such as free text may require an active matrix row column or a pixel addressable arrangement to adequately display the visual indicator.
The display medium 124 can be a bi-stable, non-volatile display medium or can be a volatile display medium. Examples of bi-stable non-volatile mediums include but are not limited to encapsulated and un-encapsulated electrophoretic material, Cholesteric materials, polymer dispersed cholesteric liquid crystals (PDChLC), encapsulated cholesteric materials, separated redox and dye reaction materials such as Dow Commotion® display medium, ph sensitive dyes, electrothermochromics displays and thermo-chromic, zenithal bi-stable, nematic, and surface stabilized ferroelectric liquid crystals.
The display medium 124 can further comprise electronic ink, wherein the electronic ink is capable of displaying a graphical indicator on the electronic label. The term “electronic ink” as used herein is intended to include any suitable bi-stable, non-volatile material. The term “bi-stable” as used herein is intended to indicate that the particles of the imaging material can alternately occupy two stable states. For example, the particles corresponding to different pixel locations of the display assembly can alternately occupy an ON or an OFF state to form selected indicia.
In an illustrative embodiment, the display media is reflective to provide a greater viewing angle to the image displayed by the electronic label. In this case, the particles in the imaging material can be oriented in a first state to reflect light (ON) or a second state to absorb light (OFF). The term “non-volatile” as used herein is intended to denote that the imaging material has indefinite memory without power and will retain an image in the absence of power to the electronic label. The particles in the imaging material maintain a first state unless actively directed to change to a second state. Thus, the imaging surface of the label shows a high-quality image even when power to the label is turned off. The electronic ink can also be a printable, conductive ink having an arrangement of particles or microscopic containers or microcapsules. Each microcapsule has disposed therein an electrophoretic composition of a fluid, such as a dielectric or emulsion fluid, and a suspension of colored or charged particles or colloidal material. The diameter of the microcapsules typically ranges from about 30 to about 300 microns.
According to one practice, the particles visually contrast with the dielectric fluid. According to another example, the electronic ink can include rotatable balls that can rotate to expose a different colored surface area, and which can migrate between a forward viewing position and/or a rear non-viewing position, or both. On example of such a material is a gyricon. Gyricon is a material comprised of twisting rotating elements contained in liquid-filled spherical cavities and embedded in an elastomer medium. The rotating elements can be made to exhibit changes in optical properties by the imposition of an external electric field. Upon application of an electric field of a given polarity, one segment of a rotating element rotates toward, and is visible by an observer of the display. Application of an electric field of opposite polarity, causes the element to rotate and expose a second, different segment to the observer. A gyricon display maintains a given configuration until an electric field is actively applied to the display assembly. Gyricon particles typically have a diameter of about 100 microns. Gyricon materials are disclosed in U.S. Pat. No. 6,147,791, U.S. Pat. No. 4,126,854 and U.S. Pat. No. 6,055,091, the contents of which are herein incorporated by reference.
A reference electrode layer 122 can be used in conjunction with the electronic ink disposed upon a display medium 124 and a backplane 126 to form an electronically activatable and addressable electronic display 18. The electrode and backplane can be disposed on, or cover opposite sides of the microcapsule arrangement, or both to provide structure for creating a potential difference across the electronic ink that causes particles within the microcapsules to migrate toward one of the electrodes. This migration can change the color of the sphere, and hence the pixel location, as viewed by an individual. According to one practice, the microcapsules can be filled with electrically charged white particles in a black or colored dye. Examples of electronic ink and methods of fabricating assemblies capable of controlling or effecting the orientation of the ink suitable for use with the present invention are set forth in International Patent Application Publication Number WO 98/41899, International Patent Application Publication Number WO 98/19208, International Patent Application Publication Number WO 98/03896, and International Patent Application Publication Number WO 98/41898, the contents of which are herein incorporated by reference.
The term electronic ink can also include a bi-stable non-volatile cholesteric imaging material. The cholesteric liquid crystal material has positive dielectric anisotropy and can include a chiral material in an amount effective to form focal conic and twisted planar textures. Typically cholesteric imaging material comprises liquid crystal cells ranging in thickness from about 25 microns to about 50 microns. Suitable cholesteric materials are disclosed for example in U.S. Pat. No. 6,154,190, U.S. Pat. No. 6,061,107 and U.S. Pat. No. 5,847,798, the contents of which are incorporated herein by reference.
In addition, the electronic ink can include zenithal bi-stable display technology to form the bi-stable nonvolatile display assembly comprised of a bi-stable nematic liquid crystal device cell. The bi-stable nematic cell is provided with a surface alignment grating on at least one cell wall and a surface treatment on an opposite cell wall. The material is activated by dc pulses to form an image. Suitable zenithal bi-stable devices are disclosed in U.S. Pat. No. 6,151,096, world patent application number WO09804953A1, world patent application number WO09934251A1, U.S. Pat. No. 6,054,973, world patent application number WO00052671A1, and U.S. Pat. No. 6,151,096, the contents of which are herein incorporated by reference.
Further, the electronic ink can include a thermo-chromic material. A thermo-chromic material is capable of changing its state alternately between transparent and opaque upon the application of heat. In this manner, a thermo-chromic imaging material develops images through the application of heat at specific pixel locations in order to form an image. The thermo-chromic imaging material retains a particular image until heat is again applied to the material. The display assembly is reusable, rewritable, non-volatile, bi-stable. Visually, black characters are written in a transparent background by applying heat to selected locations or pixels in the display layer. To form color displays other colors, such as red, yellow, and blue are used. Since the rewritable material is transparent, UV fluorescent printings, designs and patterns underneath can be seen through.
The electronic ink can also include surface stabilized ferrroelectric liquid crystals (SSFLC). Surface stabilized ferroelectric liquid crystals confining ferroelectric liquid crystal material between closely-spaced glass plates to suppress the natural helix configuration of the crystals. The cells switch rapidly between two optically distinct, stable states simply by alternating the sign of an applied electric field.
Magnetic particles suspended in an emulsion comprises an additional imaging material suitable for use with the present invention. Application of a magnetic force alters pixels formed with the magnetic particles in order to create, update or change human readable indicia, machine readable indicia or both. Those skilled in the art will recognize that a variety of bi-stable non-volatile imaging materials are available and may be implemented in the present invention.
The electronic label can further include an electronics layer 129 which can include an electronics module 127. The electronics module can control the activation of the display medium 124. The electronics module 127 can contain one or more silicon chips, programmable microcontrollers or discrete components used in displaying a visual indicator on the display medium 124. The electronics module can further include one or more sensors. These sensors can monitor the external environment in which the electronic label 14A is operating. For example, in one embodiment an external temperature sensor can be employed so that in the event that the electronic display 18 experiences a period below freezing a visual indicator on the display medium can be displayed to a user. Sensors may further monitor humidity, Ph, sunlight, ultraviolet light, chemicals, radioactivity, pathogens, bacteria, viruses or pryons in the environment surrounding the electronic display 18.
Furthermore, the electronics module 127 can transmit and receive information to and from a location using any suitable communication link, such as a standard electrical cable, optical fiber, wireless network or any suitable direct or indirect connection or link. The applications and embodiments described below generally employ radio signals transmitted and received through an applicable antenna associated with the electronics module 127.
The electronic label 14I can also contain conductive traces 128. The conductive traces can be oriented such that upon assembly of the electronic label 14I electrical continuity between the conductive traces 128 on the backplane layer 126 and the electronic layer 129 can be established by way of embedded electrical contact points 125.
The electronic label 14I can retain a visual indication on the display medium 124 for a period of time after power to the display medium is removed. The time period for which this visual indicator on the display medium remains present may be controlled by the material properties of the display medium 124, can be controlled by the electronic hardware 127 located on the electronic layer 129, or can be a function of the external environment in which the electronic label 14I is operating. The illustrated electronic label 14I may be of varying size and shape as understood by those skilled in the art. For example, the electronic label 14I may be sized to fit on a shipping container or a pallet. Furthermore, the electronic label 14I can be sized to fit on a envelope, or can be sized to cover a portion of a shelf in a supermarket.
It will thus be seen that the invention efficiently attains the objects set forth above, among those made apparent from the preceding description. Since certain changes may be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are to cover all generic and specific features of the invention described herein, and all statements of the scope of the invention which, as a matter of language, might be said to fall there between.