Patent Application
20140176507
Printed electronics enables the integration of electronic, optical and other functionalities into products at potentially ultra-low cost. In order to provide power to electronic circuits, often printed batteries are discussed, but they have several disadvantages. Batteries employ electrolytes which make the fabrication (particular with respect to sealing or encapsulation) relatively complex and, moreover, batteries lose charge over time. Piezoelectric power sources can be fabricated more easily with a smaller form factor, and there is little concern of becoming non-functional because of lost charge.
In one aspect of the presently described embodiments, the device comprises a substrate, a piezoelectric power source on the substrate, a plurality of sensing elements on the substrate connected to the piezoelectric power source, the sensing elements being operative to change electronic state upon detection of a substance, and, a plurality of display elements on the substrate corresponding to the plurality of sensing elements on the substrate, the display elements being operative to display based the electronic state of the corresponding sensing elements when the piezoelectric power source is activated.
In another aspect of the presently described embodiments, the sensing elements are resistive elements and the electronic state is resistance.
In another aspect of the presently described embodiments, the sensing elements are capacitive elements and the electronic state is capacitance.
In another aspect of the presently described embodiments, the sensing elements comprise thin film transistors.
In another aspect of the presently described embodiments, the sensing elements comprise chemical field effect transistors.
In another aspect of the presently described embodiments, the sensing elements have diffusion barriers of varying thickness.
In another aspect of the presently described embodiments, the display elements comprise at least one of reflective display elements, emissive display elements, electrophoretic display elements, electrochromic display elements, MEMS display elements, Gyricon display elements, powder display elements, liquid crystal display elements, electrowetting display elements, electrochemical display elements, electroluminescent display elements, or OLED display elements.
In another aspect of the presently described embodiments, the display elements are voltage-driven display elements.
In another aspect of the presently described embodiments, the display elements are current driven display elements.
In another aspect of the presently described embodiments, the substrate is formed of at least one of a plastic or polymer material, paper, thin flexible metal, thin flexible glass or ceramic material.
In another aspect of the presently described embodiments, the piezoelectric power source is formed of a polymeric piezoelectric material, piezo-composite material, ferro-electric material or inorganic piezo materials.
In another aspect of the presently described embodiments, the method comprises removing a protective sheet from a sensor device, exposing sensor areas of the sensor device to the substance to initiate a reaction between sensing elements in the sensor areas and the substance to change a state of the sensing elements, agitating a piezoelectric power source on the sensor device, and, changing a display on the device based on the change of the state of the sensing elements, the display being powered by the piezoelectric power source.
In another aspect of the presently described embodiments, the sensing elements comprise resistive elements.
In another aspect of the presently described embodiments, the sensing elements comprise capacitive elements.
In another aspect of the presently described embodiments, the display comprises display elements.
In another aspect of the presently described embodiments, the agitating comprises at least one of bending, pushing or shaking the piezoelectric power source.
In another aspect of the presently described embodiments, the changing of the display comprises changing a color of a display element.
In another aspect of the presently described embodiments, the changing of the display comprises changing a timeline on the sensor device.
a) and (b) show a representative view of an example device according to the presently described embodiments;
The presently described embodiments relate to, in one form, an electronic sensor device or card which is powered by a piezoelectric source (such as a strip or foil), and includes an electronic sensing element and a display element. The elements of the card, in at least some forms, are printed on the device or card. The card or device may be used to test for the presence of a substance such as a gas, a liquid, a chemical substance or a biological substance, . . . etc. For example, as will be discussed hereafter in connection with
With more particular reference to
The display elements 20, 22, and 24 are powered by the charge of the piezoelectric element 30. The display elements 20, 22, and 24 may take a variety of forms. However, some examples of display elements include reflective and emissive display elements such as electrophoretic display elements, electrochromic display elements, MEMS (Micro Electro Mechanical System) display elements, Gyricon display elements, powder display elements, liquid crystal display elements, electrowetting display elements, electrochemical display elements, electroluminescent display elements, OLED (organic light emitting diode) display elements and display elements using other suitable display technologies.
As noted above, a battery source is generally too sophisticated for a device according to at least some of the presently described embodiments because the readout of the sensor only takes a short time. Accordingly, in at least some forms, a power source such as the piezoelectric power source 30 is implemented. In this regard, a polymer piezoelectric material such as PVDF (polyvinylidene fluoride) or PVDF-TrFE (polyvinylidene fluoride-Trifloroethylene) copolymer or other known piezoelectric polymer material may be applied to a substrate using printing or lamination methods. The piezoelectric material may include any other material that produces a charge when mechanically stressed. Examples are piezo-composite material, ferro-electret material, and transferred layers of inorganic piezomaterials.
In this regard,
Referring back to
The electronic or resistive structure illustrated is merely an example. In this regard, a resistance change may occur by other means—such as simple degradation of an organic semiconductor. The semiconductor may be part of a simple resistive structure or it may be part of a TFT. Further, it is contemplated that circuits for current-driven display elements could also be implemented wherein a chemical reaction changes the resistance of an electronic element—which in turn modulates the current to the display element. Still further, instead of resistive components, capacitive components (in which the capacitance changes when reacted with a chemical substance) may be employed.
The sensor device or card 10 may be fabricated in a variety of manners. However, in at least one form, as noted above, this device is fabricated using inexpensive fabrication methods such as printing. In this regard, the electronic circuits as well as other components may be printed on the substrate. This is a factor in many implementations where the resultant device or card will likely be low-cost and disposable. Further, it should be appreciated that protective films or sheets (not shown) may be applied to a card or device to protect or isolate elements until such time as the card or device is used. The film or sheet may cover all, or part, of the card or device.
In operation, the card or device 10 according to the presently described embodiments may be manipulated in a variety of manners. For example,
In another embodiment, a sensor device or card 110 accordingly to the presently described embodiments may be also used to determine the time a product has been exposed to a chemical, gas, etc. In this regard, with reference to
In other variations, the sensor card or device may be applied (e.g. as a sticker) to a surface. In one such example, the device or card is applied to a tube which is used to suction water. When the water comes in contact with the label surrounding the tube (e.g. through a porous area in the tube where the sticker is attached), ingredients in the water react with the sensors.
Further, although in some applications a battery is not desired, there may be implementations of the present application where a battery may be used instead of a piezoelectric strip. A switch would be used to apply power for readout.
Still further, the card or device described is used in chemical/bio-testing. However, a similar concept may be used to test for pressure (or other properties) applied to the card surface.
It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
