Color Variable Lighting Device

About

A novel method of fabricating a polymer-based electroluminescent device that is capable of emitting light with two or more independent colors at room temperature. The Need Conjugated polymers have proven to be viable materials for use in electronic   displays ranging from watches, digital cameras, and cell phones to backlighting in dashboards. Polymer organic light emitting devices (P-OLEDs) have many advantages over traditional LEDs and LCD devices including elimination of complex filters and increased brightness and visibility while reducing power consumption. Potential commercial uses include consumer electronic products with larger displays (i.e., TVs, laptops), display monitors for facilities, and, on the largest end, advertising billboards. P-OLEDs have experienced limited use as a display technology partially due to limited functionality of the conjugated polymer material. Advances in manufacturing techniques that improve P-OLED performance and functionality could increase their utility in consumer goods and other commercial applications that require responsive color variance.For most P-OLEDs, the color of the emitted light is fixed once the device is fabricated; therefore developing devices that emit two or more independent colors that could subsequently combine to produce an array of colors for display purposes is desired. This has been traditionally achieved by introducing a blocking layer in between the conjugated polymer layers, but this also causes a need for an increased operating voltage. The brightness of the display is also dependent on the operating voltage, so modifying the applied voltage could adversely affect the display in most P-OLEDs. The Market The global market for electroactive polymers is expected to increase from $2.1 billion in 2011 to $3.1 billion in 2016 with conductive polymers exhibiting the largest compounded annual growth rate of 16.4%. (BCC Research) P-OLEDs are expected to account for a growing share of the OLED global market with the anticipated production increase of large-format OLED TVs which is estimated to reach $5 billion in total sales by 2018. (BCC Research) The global market for OLED panels will increase from $5.2 billion in 2013 to $25.7 billion in 2018 with a compounded annual growth rate of 37.4%. (BCC Research) Global shipments of organic materials for OLED displays are expected to increase from nearly 26 metric tons in 2013 to over 103 metric tons in 2018. (BCC Research) The Technology Researchers at The Ohio State University, led by Dr. Arthur Epstein, developed a novel method for fabricating a bipolar electroluminescent device capable of emitting light with controlled color variance. The device is comprised of at least one electroluminescent polymer sandwiched between two different redox polymer layers which modify the charge injection and transport properties of the device in order for it to operate under both forward and reverse bias. Modifying these properties could also allow for the use of electrode materials that are more stable against oxidation which can prolong the device's shelf life. At least one of the redox polymers is capable of also modifying the emission properties of the emitting polymer at the interface allowing for the emission of colors different from the light emitted from the bulk of the emitting polymer layer. The polarity of the driving voltage in combination with the charge injection and transport properties can be used to control the color of the emitted light by selecting the corresponding emission locations at the interface. The emitted light is able to change rapidly since operation is not dependent on the movement of ionic species. Category Electronics, Optronics/Photonics, Engineering & Physical Sciences, Gray (Light) Intellectual Property Issued Tech ID T1997-022