US 6,982,795 B2
Surface plasmon resonance measuring apparatus
Shu Sato, Kaisei-machi (Japan)
Assigned to Fuji Photo Film Co., Ltd., Kanagawa-ken (Japan)
Filed on Aug. 27, 2003, as Appl. No. 10/648,509.
Claims priority of application No. 2002-249684 (JP), filed on Aug. 28, 2002; application No. 2002-254727 (JP), filed on Aug. 30, 2002; and application No. 2002-287291 (JP), filed on Sep. 30, 2002.
Prior Publication US 2004/0042012 A1, Mar. 04, 2004
Int. Cl. G01N 21/55 (2006.01)
U.S. Cl. 356—455 23 Claims
OG exemplary drawing
 
1. A measuring apparatus comprising:
a measuring chip comprising
a dielectric block portion,
a thin film layer formed on one surface of said dielectric block portion, and
a sample holding mechanism for holding a sample on a surface of said thin film layer;
a light source for emitting a light beam;
an optical incidence system for causing said light beam to enter said dielectric block portion at angles of incidence so that a total internal reflection condition is satisfied at an interface between said dielectric block portion and said thin film layer;
photodetection means, which comprises a plurality of light-receiving elements, for detecting intensities of said light beam whose incidence angles are different, totally reflected at said interface;
differentiation means for differentiating an optical detection signal output from each of the light-receiving elements of said photodetection means, in a direction where said light-receiving elements are juxtaposed, at intervals of outputs of two adjacent light-receiving elements; and
computation means for specifying a reference light-receiving element by a predetermined method, then judging whether or not values of the optical detection signals of a first predetermined number of light-receiving elements increase monotonously in directions going to both sides with said reference light-receiving element as center, and computing a position of a dark line, contained in said light beam reflected at said interface, on the basis of a value obtained by differentiating the outputs of a second predetermined number of light-receiving elements sandwiching said reference light-receiving element when it is judged that the values of the optical detection signals increase monotonously, in said direction where said light-receiving elements are juxtaposed.