Patent ID: 8196451
Filing Date: 2012-06-12
Classification: G01G,G01N

Abstract:
1. A detection sensor comprising: a disk-shaped resonator having a vibration characteristic changed by adherence or adsorption of a substance having a mass; a driving unit that causes vibration of the resonator; and a detection unit that detects a change in vibration of the resonator to detect the substance, wherein the resonator having a ring shape with an outer diameter Ra and an inner diameter Rb with an opening formed at the center; the resonator being formed of the outer diameter Ra and the inner diameter Rb that substantially satisfy U(r)=0 or V(r)=0 when r=Ra or Rb for displacement U(r) in a radial displacement and displacement V(r) in a tangential direction expressed by Expression (19) in a position r on a position coordinate (r, θ) when the resonator vibrates; and the resonator is supported on an anchor by a single-span beam set so that a boundary condition on a side of the resonator is pinned and a boundary condition on a side of the anchor that supports the resonator is clamped, where Expression 19 is expressed as: where σ represents Poisson's ratio of a resonator material, E represents Young's modulus of the resonator material, ρ represents a density of the resonator material, ω represents angular frequency, n represents a degree of vibration mode, and A wherein the single-span beam has a length and a width set so that a vibration frequency thereof is substantially equal to a vibration frequency of the resonator.