Monolithic micro-spectrometer for low-cost sensing in materials processing
We have developed a monolithic micro-spectrometer suitable for a variety of sensing applications including industrial process monitoring. The device consists of a solid structure with a volume less than 6 cubic centimeters. All optical components of the spectrometer including two aspheric mirrors, a diffraction grating, and entrance and exit surfaces are fabricated onto the surface of the structure. All light paths are internally contained within the structure. The result is a small, rugged spectroscopic sensor ideally suited for use as a process monitor. Due to its monolithic nature the device requires no post-fabrication alignment; nor can it be knocked out of alignment during use. Although many materials and thus wavelength regions were possible, the prototype device discussed here was produced in PMMA by precision diamond turning. However, lower cost manufacturing approaches involving injection molding are under development to produce an affordable sensor. It is expected that modified versions of this sensor designs will be required for specific applications so as to maximize the performance and resolution over the operating range. For example, the prototype device described here operates over a wavelength range of 500 nm to 1000 nm. The performance of this device as a real-time surface monitoring sensor will be discussed in detail. Our approach of using wavelength dependent scattering resulted in the reduction to practice of a miniature, monolithic, rugged, low-cost, micro-instrument in a sensor sized package. The process sensor applications community has been faced by the cost versus performance issue. Simple go/no-go sensors are typically inexpensive but they provide very limited and sometimes dubious data. Scaled down traditional instruments offer very good measured information but are typically cost prohibitive, fragile, and still relatively large. This work will bridge the gap between these two extreme sensing alternatives.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Human Resources and Administration, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 459711
- Report Number(s):
- CONF-970201-10; ON: DE97003108
- Resource Relation:
- Conference: 126. annual meeting of the Minerals, Metals and Materials Society, Orlando, FL (United States), 9-13 Feb 1997; Other Information: PBD: [1997]
- Country of Publication:
- United States
- Language:
- English
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