Tag Archives: light

Advanced High-Efficiency Nanowire LEDs

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Summary:

There is great interest in developing new solid state semiconductor-based light emitting diodes (LEDs) that exhibit new functionality and performance. Principal challenges in creating new semiconductor LED structures include the formation of defects and low doping efficiency, both of which negatively affect device performance. To overcome these challenges, researchers at The Ohio State University have developed new methods and device structures that lead to defect-free, high-efficiency nanowire LEDs. These LEDs can be easily mass manufactured and integrated in silicon electronics, and can hit any bandgap due to the lack of strain relaxation.

Potential Applications:

  • Lighting
  • Laser diodes
  • Photodetectors
  • Communications
  • Sensors

Advantages:

  • Defect-free formation during epitaxial growth
  • Extremely high-efficiency
  • Low resistance
  • Enables simple and broad bandgap engineering
  • Low manufacturing costs and easy integration into Si electronics

Novel Organic Light Emitting Diode (OLED) Technologies for Lighting and Display Applications

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Summary:

Researchers at The Ohio State University have developed a comprehensive portfolio of Organic Light Emitting Diode (OLED) technologies that include novel materials and device architectures as platforms for functional devices and for device manufacturing. These developments improve material stability over time while improving their performance such that the required voltage can be reduced and improved electroluminescence can be obtained with reduced power consumption. The bilayer device structure improves device quantum efficiency and brightness due to charge confinement and exciplex emission at the emitting polymer interface. Beyond advancements in the materials themselves, novel device architectures have been developed which are independent of the materials used. These advancements may be of significant value in simplifying manufacturing, thereby accelerating the displacement of LCD and plasma display technologies as well as the displacement of traditional incandescent and fluorescent lighting sources. The associated patent portfolio consists of 8 patent families with a total of 11 issued U.S. patents and 39 associated national stage filings (spanning all US cases). A listing of all issued U.S. patents can be found below.

Potential Applications:

  • Conformal, designable, and color-variable interior and exterior lighting for residential and commercial environments
  • Power and weight sensitive lighting and display applications (e.g. aircraft interior lighting, portable display backlighting)
  • Portable lighting devices such as flashlights
  • Light, ultra-thin, flexible displays with rich colors viewable from very wide angles
  • Body-wearable lighting and display applications
  • Nearly endless list of potential applications

Advantages:

  • More energy efficient lighting source compared to incandescent and fluorescent approaches
  • Color quality matches or surpasses conventional approaches in lighting and display applications
  • Estimated useful life is approximately 17-25 times longer than incandescent lighting and nearly twice as long as linear flourescent lighting (which is commonly used in modern LCD displays)
  • Polymeric material is conformal to a wide range of surface topologies and allows for ultra-thin, flexible displays
  • Low cost, materials-independent architectures have the potential to lower manufacturing costs
  • Adjustable color spectrum

Device and Method for Producing Optically-Controlled Incremental Time Delays

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Summary:

Generating precise and reliable true time delays (TTDs) is of paramount importance for phased array radars and a host of other applications. True time delay avoids beam squint in wideband antenna systems. Researchers at The Ohio State University have developed a free-space optical TTD device that can provide many bits of delay (more than 15 bits) for hundreds of antenna elements in ultra-compact form (half a cubic foot) with delays varying from femtoseconds to tens of nanoseconds. The invention uses a single MEMS chip, free space for massive overlapping of beam space, and a handful of mirrors. A programmable tapped delay line has many other uses, including optical correlation, optical matched filtering, optical signal processing, optical code-division multiple access coding and decoding, photonic analog-to-digital conversion, and optical communications performance monitoring. A variation of the device can also be used for optical interconnections and routers. Electronically implementing TTDs is generally impractical because of the need for many long lengths of strip line, waveguides, or coaxial cable, which are expensive, bulky, and temperature sensitive. Since long path lengths are relatively easy to obtain optically, optical TTD systems have been developed, either using fibers or free-space paths, but these existing systems are expensive and bulky due to the use of multiple optical switches. Researchers at The Ohio State University have developed a free-space optical TTD device that uses only one optical switch or spatial light modulator for the entire system instead of one or more switches for each bit, as in previous systems. Furthermore, the device avoids beam-spreading problems that may be present in other free-space systems by using a multiple-pass optical cell with refocusing mirrors. As a result, the device is more inexpensive, compact, and temperature insensitive than existing devices.

Potential Applications:

  • Optical multiplexing/demultiplexing applications
  • Optical routing and switching
  • Phased array radars
  • Optical signal processing
  • Optical performance monitoring

Advantages:

  • Uses only one optical switch or spatial light modulator
  • Ultra-compact form factor
  • Small component count

Cantilever Couplers for Intra-Chip Coupling to Silicon Photonic Integrated Circuits

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Summary:

As electronics continue to get smaller and faster, standard copper connections between devices will prove to be inadequate for transmitting such high-bandwidth data. A more efficient and high-bandwidth solution is to use photonics, where data is transmitted via light in fiber-optic cables rather than via electrons on a copper wire. Photonic components are expensive, however, and in order to reach mass manufacturing status photonics must somehow be integrated into circuits based on silicon. This is difficult as coupling light directly to silicon integrated circuits has required dicing or cleaving the circuit in some way. Researchers at The Ohio State University have invented a way to efficiently couple light from an optical fiber to silicon photonic integrated circuits at any location on the surface of the circuit without the need to dice or cleave the circuit. This is achieved using on-chip cantilever couplers that can be fabricated using standard CMOS processes used in the semiconductor integrated circuit industry. This technique is an important step towards the widespread realization of optoelectronic devices based on silicon.

Potential Applications:

  • Optical interconnects
  • Low-cost telecommunications
  • Optical Sensors
  • Could revolutionize computing by allowing nearly limitless bandwidth

Advantages:

  • Couples light to silicon photonic ICs without the need to dice or cleave the circuit
  • Efficient and low-loss coupling method
  • Can couple light at any location on the surface of the circuit
  • Cost effective and mass producible as the invention is silicon-based