Patent ID: 7291838

Claim:
A scattered material detection apparatus using a terahertz wave, comprising: (a) terahertz wave generation device which generates the terahertz wave; (b) a terahertz wave irradiation device which irradiates an object to be inspected with the terahertz wave, wherein the terahertz wave irradiation device comprises i. a lens that converts the generated terahertz wave into parallel light; and ii. an iris diaphragm that limits a sectional shape of the parallel light to be smaller than that of the object to be inspected to irradiate the object with light; and (c) a scattering intensity detection device for cutting a rectilinear wave of the terahertz wave which has passed through the object to be inspected and for detecting an intensity of a scattered wave, wherein the scattering intensity detection device comprises i. a confocal optical system for interrupting the terahertz wave that has rectilinearly passed through the object to be inspected midway and for focusing the terahertz wave scattered by the object to be inspected in a predetermined position; and ii. a scattering intensity detection unit that detects the intensity of the terahertz wave in the focal position.