Steven B Day

US Patent:

47309210, Mar 15, 1988

Filed:

Oct 31, 1985

Appl. No.:

6/793653

Inventors:

Gerald L. Klein - Edmonds WA
Gene D. Russell - Seattle WA
Steven R. Day - Bothell WA
Jerrold D. Liebermann - Seattle WA

Assignee:

Genetic Systems, Inc. - Seattle WA

International Classification:

G01N 3348

US Classification:

356 39

Abstract:

An automated vertical photo densitometer for reading solutions contained in microwell plates. The densitometer utilizes an optical system for minimizing the optical effect of a meniscus on the fluid sample. The invention also discloses a method for determining a centrally located position of a microwell beneath an interrogating beam of light by controlling the size of the light beam and by stepping the well through the beam. A measurement of the light intensity received by a detector is taken at each step. A maximum light intensity value is selected as corresponding to a well position wherein a central area of the fluid sample is substantially within the interrogating beam.