Thermal measuring and testing – Determination of inherent thermal property
Patent
1995-07-31
1997-04-15
Gutierrez, Diego F. F.
Thermal measuring and testing
Determination of inherent thermal property
374 44, 364556, G01N 2520
Patent
active
056202539
ABSTRACT:
The thermal resistivities W.sub.s (=1/.kappa..sub.s) of electrically insulating, crystalline or polycrystalline samples under test (SUTs), all comprising host material such as CVD diamond, can be determined rather quickly once the thermal resistivities W=1/.kappa. of at least two other host crystalline or polycrystalline bodies B.sub.1 and B.sub.2 comprising the same host material as that of the SUTs, and containing the same type of impurity or combination of impurities as the SUTs, are measured by some other technique. These determinations of these thermal resistivities W.sub.s of the SUTs thus require only the measurements of the optical absorptivities .alpha..sub.1 and .alpha..sub.2 and of the thermal resistivities W.sub.1 and W.sub.2, respectively, of at least each of the two other bodies B.sub.1 and B.sub.2 and only of the optical absorptivities .alpha..sub.s of each of the SUTs by such other technique. These determinations of W.sub.s rely on our discovery that the following linear relationship exists: W=A+C.alpha., where A and C are constants so long as the type of impurity or combination of impurities in all the bodies B.sub.1, B.sub.2, and SUTs is the same, even though the impurities or combination of impurities have different concentrations in the bodies B.sub.1 and B.sub.2, as well as in the SUTs.
REFERENCES:
patent: 3552185 (1971-01-01), Goode, Jr. et al.
patent: 3611786 (1971-10-01), Schorr
patent: 4372691 (1983-02-01), Buckley
patent: 4522512 (1985-06-01), Atkins
patent: 5297868 (1994-03-01), Graebner
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E. A. Burgemeister, "Thermal Conductivity of Natural Diamond Between 320 and 450 K," Physica 93B (1978) pp. 165-179. Comment: As shown in FIG. 1 and accompanying text of this reference, the thermal conductivity of diamond was first measured by means of traditional heat-flow techniques pp. 166-167, especially equation 1). In addition the thermal conductivity of diamond was also measured by means of an infrared absorption technique, but using essentially only one single infrared wavelength at a time, i.e., and extremely narrow spectral range (p. 169, col. 2; p. 173, legend beneath FIG. 5). By contrast, the present invention recognizes that a much wider spectral range can and should be used, which takes the technique out of the laboratory and into the commercial world since the invention does not require spectrometer devices as does the prior art.
D. T. Morelli et al., "Correlating Optical Absorption and Thermal Conductivity in Diamond," Appl. Phys. Lett. vol. 63, No. 2, Jul. 12, 1993, pp. 165-167. Comment: This reference also teaches use of only narrow spectral ranges for each absorption measurement (FIG. 1 on p. 166). Likewise, this reference's statement regarding the relationships shown in FIG. 4 is limited to but a single wavelength at a time. There is thus no teaching here of the utility of the much wider spectral ranges taught by the present invention.
Elementary Physics: Classical and Modern, by Richard T. Weidner and Robert L. Sells, pp. 306-307 (1975). Comment: This reference is cited on p. 1 of applicant' specification.
Optics Guide 5, published by Melles Griot, Irvine, CA 92714, at pp. 22-29 through 22-38 (1990). Comment: This reference is cited on p. 9 of applicants' specification.
Graebner John E.
Jin Sung-ho
Caplan David I.
Gutierrez Diego F. F.
Lucent Technologies - Inc.
Pacher Eugen E.
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