Device for water examination

A water examination device comprising:

• a main body;
• a fluid accommodation unit formed in the main body;
• a wave source for irradiating waves toward the fluid accommodation unit;
• a detector for detecting a laser speckle at every set time period that is set in advance, the laser speckle being generated due to multiple scattering of the waves in the fluid;
• a controller for estimating existence of impurities in the fluid by using the detected laser speckle;
• and
• a calibration unit for controlling the wave source or the detector such that an intensity of light irradiated from the wave source and measured by the detector is within a certain range set in advance,
• wherein the fluid accommodation unit includes:
• a bottom portion formed in the main body;
• and
• a wall portion formed to have a certain angle with respect to the bottom portion and includes a reflective region,
• wherein an angle between the bottom portion and the wall portion is not a right angle,
• wherein the wall portions facing each other are inclined with respect to the bottom portion toward each other,
• wherein the wave source irradiates waves toward the wall portions, and
• wherein the fluid accommodation unit is configured to accept a cup of fluid that is separatable from the fluid accommodation unit.