Abstract:
Embodiments of the present application relate generally to methods and apparatus for relating information in a form either machine-readable, human-readable, or some combination thereof. More particularly, although not exclusively, these embodiments are concerned with the display of information on a smart active label or smart packaging where low power and low cost are significant considerations. In some embodiments, display methods are based on electronic, electromechanical, electrochemical, and combinations thereof configured or manufactured using printing techniques, micro-electromechanical system (MEMS) techniques, or combinations thereof to achieve high reliability, low cost, and low activation energies. The embodiments described above can provide an accurate and low-cost apparatus and method for relating the information obtained by smart active labels and smart packages.

Description:
RELATED APPLICATION 
   This application claims priority to U.S. Provisional Patent Application No. 60/670,508, filed Apr. 11, 2005 and entitled ELECTRONICALLY ACTIVATED DISPLAY APPARATUS AND METHOD, the disclosure of which is incorporated herein by reference in its entirety. 

   BACKGROUND 
   Embodiments of the present application relate generally to methods and apparatus for electronic and electrically activated displays. More particularly, although not exclusively, these embodiments are concerned with small, low cost, low power electronic and electrically activated displays for use in product and packaging labels. 
   It is generally desirable in the art of making smart labels and smart packaging products to be able to relate information obtained by the smart label sensor in a low energy and low cost manner. Such methods of relating information can be used in quality control and quality assurance activities to improve product quality, safety, and security. Information may be related in either a machine-readable, human-readable, or a combination of both human and machine-readable forms. 
   To accomplish such information transfer, it is known in the art that certain industry standard embedded radio frequency (RF) transmitters or static bar codes may be used to relate machine-readable information. Static printed labels and enzymatic tags may be used to relate human-readable information. Liquid crystal displays (LCD) or light emitting diode (LED) displays may be used to relate both machine and human-readable information. 
   When considering the update in information made available by the smart label or smart package, a static bar code or static printed message is not useful. When considering the limited energy available to a smart label or package, industry standard RF transmitters, LCD, and LED displays are not practical for extended use. Passive RF transmitters may be used in limited application without additional energy requirements, however, better reliability is obtained with active, or battery assisted, RF transmitters. Industry standard LCD options are further constrained by their useful operating temperature range. Enzymatic and similar displays presently provide only a general indication of an event without variations or details. 
   Additionally, when considering the cost of goods required to build such displays into smart labels and smart packages, even at the smallest levels of integration (deep sub-micron), using fully custom Application Specific ICs (ASICs), the cost of goods may be too high to be applicable in a typical case-ready packaging situation. Cost sensitivities drive the need for lower-cost and lower-power methods for relating information for smart label and smart packaging devices. 
   SUMMARY 
   The architecture and fabrication methods of the present application provide lower-cost signal display and information transfer options through combinations of chemical, mechanical, and electronic systems. 
   It is understood that circuit elements such as transistors, resistors, capacitors, LEDs, and high grade conductors can be fabricated directly upon polyethyleneterephthalate (PET) substrates using ink-jet printing methods. It is also understood that silicon may be etched to make small mechanical parts and machines, much the way integrated circuits are manufactured. The systems and methods described herein apply these methods, in combination with the use of silicon-based circuits, to achieve low-cost and low power display and information transfer systems. 
   In one embodiment, a variable display system for a perishable product comprises an environmental sensor configured to sense one or more environmental conditions of the perishable product, a controller in communication with the environmental sensor, and a variable display element in communication with the controller via a display driver. The variable display element comprises a reservoir containing ink or a reactive agent. In addition, the controller is configured to modify the appearance of the variable display element by transmitting an electronic control signal to the variable display element in response to a selected change in the environmental conditions of the perishable product, as sensed by the environmental sensor. 
   In another embodiment, a variable display system for a perishable product comprises an environmental sensor configured to sense one or more environmental conditions of the perishable product, a controller in communication with the environmental sensor, and a variable display element in communication with the controller via a display driver. The controller is configured to modify the appearance of the variable display element by transmitting an electronic control signal to the variable display element in response to a selected change in the environmental conditions of the perishable product, as sensed by the environmental sensor. In addition, the variable display element comprises an electrochemical material configured to change optical characteristics in response to the electronic control signal. 
   In another embodiment, a variable display system for a perishable product comprises an environmental sensor configured to sense one or more environmental conditions of the perishable product, a controller in communication with the environmental sensor, and a variable display element in communication with the controller via a display driver. The controller is configured to modify the appearance of the variable display element by transmitting an electronic control signal to the variable display element in response to a selected change in the environmental conditions of the perishable product, as sensed by the environmental sensor. In addition, the variable display element comprises one or more electromechanical components configured to move in response to the electronic control signal. 
   These and other embodiments of the present application will be discussed more fully in the detailed description. The features, functions, and advantages can be achieved independently in various embodiments of the present application, or may be combined in yet other embodiments. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram of one exemplary embodiment of a display driver system. 
       FIG. 2  is a schematic diagram of one embodiment of a variable “Use By” or “Sell by:” packaging date stamp. 
       FIG. 3  is a schematic diagram of one embodiment of a variable bar code display. 
       FIG. 4  illustrates various exemplary embodiments of bi-stable, low power, ink-based display elements. 
       FIG. 5  illustrates various exemplary embodiments of electrochemical displays. 
       FIGS. 6-8  illustrate various exemplary embodiments of MEMS based display elements. 
       FIG. 9  is a schematic diagram of exemplary embodiments of graphical display elements using any of the disclosed display methods. 
   

   DETAILED DESCRIPTION 
   In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific illustrative embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that various changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense. 
     FIG. 1  shows a basic schematic configuration of one exemplary embodiment of a display driver system  100 . In the illustrated embodiment, the system  100  comprises at least one sensor  105  and timer  110  in communication with a controller  115 , such as an analog controller circuit or a programmable logic device (PLD) controller. As illustrated, the controller  115  includes environmental information  120  regarding one or more environmentally-sensitive products, such as perishable products (e.g., meat, poultry, seafood, dairy products, cosmetics, chemicals), temperature-sensitive devices, components or structures, etc. The controller  115  is in communication with a display driver  125 , which in turn communicates with a display  130 , such as the date display  200  shown in  FIG. 2  or the variable bar code display  300  shown in  FIGS. 3A and 3B . 
   In operation, the system  100  controls the display  130  based on sensor input to the controller  115 . One or more sensors  105  feed information to the controller  115 , which makes a determination of whether or not the display  130  needs to be changed and by how much. Based on this assessment, the controller  115  signals the display driver  125  to make a change to the display  130 . This display driver  125  may be integrated into the controller  115  or a separate unit. The display  130  and associated methods described below may be used in a variety of forms, including graphical display elements for such tasks as a freshness or doneness indicator. 
   The display  130  may comprise part of a smart active label (SAL) or intelligent package (IP) with an incorporated sensor, and the SAL or IP controlling the display  130 . A “Use by” date can be more accurately posted by allowing the SAL or IP to update the date based on freshness information and environmental conditions of the related product. In some embodiments, the UPC changes after spoilage to identify a different product, such as a spoiled product. 
     FIG. 2  illustrates a portion of one exemplary embodiment of an integrated UPC and “Use By” or “Sell By” date display  200  that updates to match measured freshness values of a product. The date display  200  comprises one or more variable display elements  205 , such as alphanumeric characters representing a display date, which can be modified based on a freshness assessment. The date display  200  further comprises one or more static display elements  210 , such as a printed legend located below the display date. In the illustrated embodiment, the variable display elements  205  comprise segmented display characters, whereas in other embodiments, the variable display elements  205  may comprise dot matrix displays, character overlay displays, etc. 
   In some embodiments, the date display  200  comprises a variable date stamp, which can be used to relate “Use By” or “Sell-By” information on perishable products. The display  200  is preferably low power and bi-stable, such as NTERA nanotubes or e-Ink electrostatic colored balls. The display  200  may also comprise mechanical MEMS-based sliding or flipping displays. Given a variety of uses, the display  200  may also comprise a liquid crystal display (LCD), light emitting diode (LED), or electroluminescence (EL) display. Low power EL inks make it possible to print the display  200  directly on a plastic substrate for mass produced labels. 
     FIG. 3  illustrates one exemplary embodiment of a variable bar code display  300 . In the illustrated embodiment, the bar code display  300  comprises a plurality of variable bar code characters  305 , as well as a plurality of optional alphanumeric characters  310 . Both the bar code characters  305  and the alphanumeric characters  310  may be partially printed in ink and partially variable displays. The display  300  may comprise electronically actuated micro-inkjet, or electronic display using LCD, LED, EL, MEMS, or bi-stable display material. 
   In some embodiments, each bar code character  305  is represented by one or more adjacent vertical pixels, which are long and narrow, e.g., the width of a single bar code element. The display of adjacent pixels can be selectively controlled to adjust the width, and hence the numerical value, associated with a given bar code character  305 . Therefore, as described above, a sensor  105 , controller  115 , and display driver  125  can be used to alter the UPC code represented by the variable bar code display  300  when spoilage or another selected condition occurs. In this scenario, a manufacturer could secure additional UPC codes to assign to products in a modified condition, which could help the manufacturer in monitoring and tracking of returned goods. 
     FIG. 4  illustrates various embodiments of bi-stable, low power, ink-based display elements  400 . In these embodiments, an electronically-released ink or dye is used for display purposes. The ink-based display elements  400  may comprise part of a smart active label (SAL) or intelligent package (IP) with an incorporated sensor, and the SAL or IP controlling the display. A change in the portion of a label or identification area on the SAL or IP caused by the activation of an ink-based display element  400  could indicate a change in the product as determined by the sensors and algorithms of the SAL or IP. An area on the label or package may be filled with a color, or a different alphanumeric character may appear in a code, or the UPC label may change to a different number. This change in color or state could result from material released from a reservoir by any of a variety of means including fuse-like bursting of a containment wall, electromechanical linkages, and single inkjet-like nozzles. 
   In general, the ink-based display elements  400  shown in  FIG. 4  have an ink reservoir and a projector or mover for the ink. These display elements  400  may also include a shaped space or particular wicking material to enhance the speed or shape of the display. The ink projector-mover may take a variety of forms, including a small ink jet nozzle, which may be similar in the form of standard industry printer nozzles, or based on a piezo-electric pump. 
   For example, display element  400 A comprises an ink reservoir  405 , a display area  415  comprising a wicking material or capillary space, and a flash barrier  410 , which initially separates the ink reservoir  405  from the display area  415 . While the display area  415  has a generic rectangular shape in the illustrated embodiment, those of ordinary skill in the art will understand that the display area  415  may have any of a wide variety of desired shapes and sizes. For example, the display area  415  may comprise one or more segments in a segmented display, one or more dots in a dot matrix display, one or more pixels in a variable bar code display, etc. The barrier  410  may comprise a small resistive material that is destroyed when a sufficient electrical current passes through it, such as a fuse. In operation, when the barrier  410  is removed or destroyed, the ink in the reservoir  405  moves into the display area  415  through wicking action or capillary motion. 
   Display element  400 B comprises an ink reservoir  420 , a MEMS based linear actuator  425  and plunger  430  located on one side of the reservoir  420 , a nozzle  435  located on the other side of the reservoir  420 , and an optional display area  440  comprising a wicking material or capillary space located adjacent to the nozzle  435 . The optional display area  440  may have any desired shape and size. Upon activation, the MEMS based linear actuator  425  moves the plunger  430  to squeeze the ink out of the reservoir  420  through the nozzle  435  and into the optional display area  440  (if present). 
   Display element  400 C comprises an ink reservoir  445 , a piezo film  450  located on one side of the reservoir  445 , a nozzle  455  located on the other side of the reservoir  445 , and an optional display area  460  comprising a wicking material or capillary space located adjacent to the nozzle  455 . In operation, the piezo film  450  acts as a pump that, upon activation, squeezes the ink out of the reservoir  445  through the nozzle  455  and into the optional display area  460  (if present). 
   Display element  400 D comprises an ink reservoir  465  having a desired shape and size, as well as an upper surface  470  comprising a flash barrier or other suitable material. In operation, the upper surface  470  can be destroyed or disrupted by an electrical pulse, thereby revealing the ink stored in the reservoir  465 . In other embodiments, the top surface  470  may comprise an enzymatic material to create a “timed” or organic time-temperature integration display. 
   Display element  400 E comprises an ink reservoir  475  having a desired shape and size, a piezo oscillator  480  located on a lower surface of the reservoir  475 , and one or more nozzles  485  located on an upper surface of the reservoir  475 . In operation, the piezo oscillator  480  acts as a pump that squeezes the ink out of the reservoir  475  through the one or more nozzles  485  upon activation. 
   Display element  400 F comprises an ink reservoir  490 , a piezo film  492  located on an upper and lower surface of the reservoir  490 , a nozzle  494  located on one side of the reservoir  490 , and an optional display area  496  comprising a wicking material or capillary space located adjacent to the nozzle  494 . In operation, the piezo film  450  acts as a pump that, upon activation, squeezes the ink out of the reservoir  445  through the nozzle  455  and into the optional display area  496  (if present). 
   As an alternative to ink, the display elements  400  could use a reactive agent in their respective reservoirs to change the color of a wicking agent or a pre-printed area on the display or its surface. The display elements  400  can be driven by a system  100  like that shown in  FIG. 1 . Once activated, these display elements  400  would be one-time-use, and could not be altered or changed again. These display elements  400  may be activated as a fail-safe display method when the display or label power source nears the end of its operational life. 
     FIG. 5  illustrates various embodiments of electrochemical displays  500 . These displays  500  may comprise part of a smart active label (SAL) or intelligent package (IP), with an incorporated sensor and the SAL or IP controlling the display. A change in the portion of a label or identification area on the SAL or IP caused by the activation of an electrochemical display  500  could indicate a change in the product as determined by the sensors and algorithms of the SAL or IP. An area on the label or package may change color, or a different alphanumeric character may appear in a code, or the UPC label may change to a different number. This change in color or state could result from electrically stimulating the electrochemical material. 
   In general, the electrochemical displays  500  shown in  FIG. 5  comprise inks or other materials that change optical characteristics, such as color or transparency, when a voltage or current is applied to them. Preferably, these inks or other materials are bi-stable, similar to dithienylethene type compounds. These chemicals may be held in a reservoir or printed on a substrate. Each display  500  comprises one or more display elements in electrical communication with a positive electrode  510  and a negative electrode  520 , which can be used to apply an electrical voltage or current to control the appearance of the respective display elements. 
   As illustrated, the electrochemical displays  500  may comprise a wide variety of suitable shapes and sizes. For example, displays  500 A and  500 B comprise generic dot or pixel display elements  525 , display  500 C comprises an alphanumeric display element  530 , display  500 D comprises a plurality of vertical pixels  535  that can be used in connection with a variable bar code display  300 , display  500 E comprises a plurality of adjacent rectangular display elements  540  to form a variable bar graph display, and display  500 F comprises a plurality of segment display elements  545  to form a segmented display. Other suitable shapes and sizes will become apparent to those of ordinary skill in the art. 
   In operation, the electrodes  510 ,  520  can be activated and controlled with a system  100  similar to that shown in  FIG. 1 . In addition, the electrochemical displays  500  shown in  FIG. 5  can be colorized to enhance readability. Displays for smart active labels and packaging are preferably low-power and bi-stable. 
     FIGS. 6-8  illustrate various embodiments of MEMS based electromechanical displays, in which one or more very small mechanical mechanisms are used to physically move contrasting pixels or areas in and out of view, or move a cover to allow the contrasting pixel elements to be seen or hidden from view. These displays provide information transfer for SAL and IP as well. 
   In operation, the appearance of a MEMS based electromechanical display is controlled by using a MEMS actuator (e.g., a rotary or linear actuator) to uncover or cover a contrasting colored area. For example, if the background is a dark color, the contrasting color may be white or blaze orange. Similarly, if the background color is a light color, the contrasting color may be black. The cover color should match that of the background color so as not to hide the contrasting colored component of the display. A MEMS based electromechanical display may be a one-time or multi-use display. A system  100  as in  FIG. 1  may be used to actuate such a display based on a predetermined condition. 
     FIGS. 6A and 6B  illustrate one exemplary embodiment of a MEMS based rotary display element  600 . In the illustrated embodiment, the display element  600  comprises a MEMS rotary actuator  605 , a rotating-flipping piece  610 , a fixed piece  615 , and a rotation constraint  620  holding the rotating-flipping piece  610  in position with the rotary actuator  605 . In some embodiments, the open face of the rotating-flipping piece  610  is the same color as the contrasting colored area, while the backside of the rotating-flipping piece  610  is the same as the background color. 
     FIGS. 7A and 7B  illustrate one exemplary embodiment of a MEMS based sliding display element  700 . In the illustrated embodiment, the sliding display element  700  comprises a MEMS linear actuator  705 , a sliding piece  710 , a fixed piece  715 , and a pair of slide guides  720 . In some embodiments, a contrasting-colored area  725  is covered or uncovered by the background-colored sliding piece  710  when the linear actuator  705  is activated. 
     FIGS. 7C and 7D  depict another embodiment of a sliding display element  750 . In this embodiment, a base or backing piece  755  is marked with pattern of contrasting color in the same way as a top, sliding piece  760  is patterned with a background color. The pattern of the backing piece  755  varies between the background color, C 1 , and the contrasting color, C 2 . The pattern of the sliding piece  760  varies between the background color, C 1 , and a clear space, C 3 , that allows the color of the backing piece  755  to show through. This clear space may also comprise holes cut into a pattern, as shown in  FIG. 7E . 
   In some embodiments, the background-colored pattern on the sliding piece  760  is slightly larger than that of the backing piece  755  to ensure that the contrasting color, C 2 , is completely covered when the pieces are overlaid, as shown in  FIG. 7C . Upon actuation, the sliding piece  760  is moved slightly allowing the contrasting color, C 2 , on the backing piece  755  to show through, as shown in  FIG. 7D . 
     FIG. 8  depicts an additional embodiment of a MEMS based display element  800 . In this embodiment, the display element  800  comprises a lower backing piece  805  and an upper sliding piece  810 . In some embodiments, the bottom of the backing piece  805  is colored with a contrasting color, whereas in other embodiments, the backing piece  805  covers the contrasting color or image. In some embodiments, the top of the backing piece  805  is fabricated from a substrate comprising a clear polarized filter, or from a clear substrate with small, aligned elements such as micro-slats or filaments, or diffraction grating. The upper sliding piece  810  can be made of the same or similar substrate as the backing piece  805 , without a bottom coloring or covering, so as to be substantially transparent. The micro-slats or filaments used are preferably colored the same as the display background color. 
   In operation, the sliding piece  810  may be slid horizontally over the backing piece  805 , as described above in connection with  FIG. 7 . Alternatively, the backing piece  805  and the sliding piece  810  may be anchored at their centers by a spindle  815  allowing rotary movement. In this configuration, the backing piece  805  and the sliding piece  810  can be held at 90 degrees to each other to cover the image or contrasting color below, or rotated into alignment to display the image or contrasting color. 
   This rotation can be accomplished using a variety of suitable mechanisms, as shown in  FIGS. 8B through 8D . For example, the spindle  815  can be rotated directly by a rotary MEMS actuator  820 , as shown in  FIG. 8B , thereby rotating either the lower backing piece  805  or the upper sliding piece  810 . Alternatively, a rotary MEMS actuator  820  can rotate gearing or a friction wheel  825 , as shown in  FIG. 8C , to rotate either the lower backing piece  805  or the upper sliding piece  810 . As another example, the rotation may be accomplished by a linear actuator  830  and linkage  835  in cooperation with a slider arm  840  attached to either the backing piece  805  or the sliding piece  810 , as shown in  FIG. 8D . 
   The display element principle illustrated in  FIG. 8  may also be accomplished by covering an image or contrasting color with a LCD that reveals what is underneath it as the LCD elements are turned off. The LCD elements may be pigmented to match a background color. The LCD may comprise a standard form of aligned liquid crystal or an anamorphic form, in which the covered image or contrast color is not revealed until activation or deactivation. 
   The MEMS based electromechanical display elements depicted in  FIGS. 6-8  can represent a wide variety of display elements, such as, for example, one or more segments in a segmented display, one or more dots in a dot matrix display, one or more vertical pixels in a variable bar code display, etc. In addition, these displays elements may be driven by a system  100  like that shown in  FIG. 1 . In operation, these display elements may be activated and re-activated to either show or hide the contrasting color, thereby changing the image and information displayed. These display configurations may also be used with backlighting to enhance readability. 
     FIG. 9  illustrates various embodiments of a smart active label  900  with graphical display options. These displays may be constructed using LCD, LED, EL, bi-stable display components such as e-ink, or with any of the display elements and associated methods described above. In some embodiments, the graphical displays shown in  FIG. 9  may be colorized to enhance readability. Displays for smart active labels and packaging are preferably low-power and bi-stable. 
   Although this invention has been described in terms of certain preferred embodiments, other embodiments that are apparent to those of ordinary skill in the art, including embodiments that do not provide all of the features and advantages set forth herein, are also included within the scope of this invention. Accordingly, the scope of the present invention is defined only by reference to the appended claims and equivalents thereof.