Abstract: A method for remotely measuring the temperature of a target maintained at a first relatively low temperature while at the same time the target is heated by thermal radiation from a source spaced from the target and maintained at a second relatively high temperature which employs a two wavelength radiometer and a computer. First and second wavelengths are selected for use. The second wavelength is shorter than the first wavelength, both source and target exhibiting appreciable radiation at the first wavelength, the source emitting appreciable radiation while the target emits essentially no radiation at the second wavelength. The radiation of the source at the first wavelength and at the second wavelength are measured. These two source radiation measurements are stored in the computer. The radiation of the target at the first wavelength and at the second wavelength are measured. These two target radiation measurements are stored in the computer.

Abstract: Pyrometer apparatus measures the temperature of a semiconductor wafer which when heated by radiation from a bank of lamps emits thermal radiation which includes radiation contained in a selected spectral band. The apparatus includes a reaction chamber supporting the wafer and disposed above the bank of lamps. A hollow envelope reflecting incident radiation and thermal radiation from the wafer surrounds and is spaced from the chamber and the bank of lamps. A portion of the reflected radiation and the thermal radiation passes upwardly through a first opening. A source of said incident radiation disposed adjacent a second opening produces radiation within said spectral band which enters said envelope and is reflected inside the envelope to illuminate a selected spot on the wafer hemispherically. The spot reflects a portion of the incident radiation upwardly through the first opening.

Abstract: Apparatus for measuring the value of the directional spectral hemispherical reflectance of the surface of a target when not engaging but being spaced from the target employs a hollow elongated member having a longitudinal axis and first and second opposite ends. The area of the first end is relatively large relative to that of the second end. The first end is open. The member has an inner chamber extending between the ends and has an inner surface adapted to reflect light falling within a specified wave band. The member when the apparatus is in use is positioned with the first end adjacent but spaced from a selected portion of the surface of the target. The longitudinal axis is oriented essentially normal to a region on the selected surface which would be engaged by a line coincident with the axis and sufficiently extended outwardly from the first end.

Abstract: The temperature of a thermally emitting target which radiates over a band of wavelengths which includes first and second spaced wavelengths and which has an unknown emissivity characteristic at which the emissivity at one wavelength may but does not necessarily differ from the emissivity of another wavelength is read remotely by [a] deriving signals from those portions of the thermal radiation at these two wavelengths; [b] deriving signals from the reflected portions of two beams of radiation at these wavelengths which strike the target; and [c] by using these derived signals to compute the temperature.

Abstract: A pyrometer adapted to be disposed remotely from a heated diffusely reflecting target obtains a first electrical signal from that portion of target radiance which reaches the instrument. A laser beam is generated within the instrument and is directed upon the target, a portion of the beam being reflected back to the instrument. A second signal is obtain from this portion. The separation between target and instrument is measured and a third signal depending on the separation is produced. A fourth signal dependent upon the power level of the beam is produced. The instrument then computes from these signals the surface temperature of the target.

Abstract: A pyrometer adapted to be disposed remotely from a heated target employs a manually operated optical range finding device for measuring the distance between the target and the pyrometer. The device includes an objective lens mounted in a rotation-type focusing mechanism, split image effect prisms and a viewing screen. A split image appears on the screen when viewing until the mechanism is rotated to a unique angular position at which the image split disappears, the unique focusing position being a monotonic function of the distance. A mechanical gearing arrangement responsive to mechanism rotation is connected to a multi-turn potentiometer having oppositely disposed fixed contacts at each end and a movable contact. The movable contact is moved along the potentiometer in accordance with rotation of the mechanism. For each unique focusing position of the lens there is a corresponding unique position of the movable contact with respect to the end contacts.