Solid-State Lighting for Use in Computers, Flat Panel TVs, and More
This organic light emitting diode (OLED) utilizes microcavities to create more efficient devices for solid state lighting. The Energy Independence and Security Act of 2007 mandated the transition to higher-efficiency bulbs. Solid-state lighting, such as OLED, has the potential to reduce the nation’s energy costs by $250 billion in 20 years. However, some solid-state lighting fails to match the performance of technologies it is replacing and is cost-prohibitive. Quality lighting requires broadband light sources that resemble the spectrum of sunlight. The Color Rending Spectrum measures this spectrum by the ability of a light source to reproduce the colors of various objects compared to those seen in natural light. White OLEDs are ideal for lighting because organic materials have wider emission spectra and higher CRI than regular LEDs. One major hindering factor to OLEDs, however, is the light extraction; light emitted from an OLED is trapped between the organic layers and the glass substrate, causing the emitted light to be less crisp. To address this problem, researchers at the University of Florida have developed a microcavity organic light emitting diode for enhanced light extraction. Using this development will increase effectiveness for numerous lighting sources in everything from computers to flat panel TVs while saving in fabrication time and costs.
Application
OLED device that produces light of one or more desired wavelengths for use in a variety of applications
Advantages
- Utilizes inorganic and organic phosphors, permitting light to be broad and uniform or direct and concentrated
- Constant thickness of the organic film layer for devices having different cavity lengths, reducing the need to specialize production for each product
- Maintains the same voltage while allowing the wavelength to vary from device to device, expanding applicability to a broad range of markets
- Ability to select a particular wavelength of the reflected light, enhancing light efficiency and output
Technology
This lighting device uses a blue emitting light together with a dielectric mirror. The blue light that is produced also will generate a yellow light due to excited phosphors. The phosphor materials can be inorganic phosphors or organic phosphors. Inorganic phosphor particles tend to scatter light more and provide more uniform light emitting devices while organic phosphors tend to give more directional light sources. After proper mixture of the two lights is achieved, a high efficiency white source is created. This efficiency can be two to three times greater than even the best OLED emitting devices on the market today. Also included with this invention is a method to fabricate the microcavity device. Dielectric mirrors are strategically placed so that the cavity can be properly tuned. This allows the wavelength of the reflected light to be selected, which creates a cavity effect. Because the wavelength can be selected, the resonance within the cavity enhances the light efficiency and output.
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