Patent ID: 8467067

Claim:
A dynamic light-scattering measuring apparatus ( 10 ) suitable for measuring a particle size of particles (S 1 ) contained in a medium (S 2 ) as a dispersion containing particles having particle sizes smaller than 100 nm or a dispersion in a multi-disperse state including having particle sizes smaller than 100 nm, the apparatus comprising: a Mach-Zehnder interferometer having: a low-coherence light source ( 1 ) for emitting low-coherence light, a first photocoupler ( 3 ) for dividing light emitted from the low-coherence light source ( 1 ) into two pieces, thereby one of the divided pieces of light to be used as a reference light, the other divided piece of light to be used as a scattering light through the dispersion (S) containing the particles (S 1 ), a light collecting device made of an objective lens ( 12 ) for collecting the scattering light from the dispersion (S), a second photocoupler ( 4 ) for combining the divided pieces of light.