Gary A Greene

US Patent:

58152547, Sep 29, 1998

Filed:

Oct 8, 1996

Appl. No.:

8/728296

Inventors:

Gary R. Greene - Penfield NY

Assignee:

Spectronic Instruments, Inc. - Rochester NY

International Classification:

G01N 2117

US Classification:

356 73

Abstract:

An apparatus and method are provided for selectively measuring color values of a transmittance sample in a transmittance mode and a reflectance sample in a reflectance mode. The spectrophotometer includes two light channels, a first light channel from a light source to a first detector and a second light channel from the same light source to a second detector. The light channels conduct the light through the spectrophotometer. The spectrophotometer includes appropriate circuitry to compare the light striking the first and second detectors to determine the color value of a sample. A transmittance cell is located in the first light channel for selectively receiving a transmittance sample. When a sample is present, light passing through the transmittance sample is altered because the sample selectively absorbs some of the wavelengths of light. The spectrophotometer also includes a reflectance measurement area in the second light channel for selectively receiving a reflectance sample.