Abstract: [Object] To provide an optical device for use with coherent terahertz light, which enables to reduce and remove an unwanted interference pattern, and to acquire a terahertz image of high image quality. [Solving Means] The optical device for use with coherent terahertz light includes an optical system (2) that uses coherent terahertz light beam (1) whose frequency(ies) is/are within a range from 0.1 to 10 THz. A structure(s) (4) being located outside of effective diameter (3) of the beam (1) and including anti-reflection material (5) on an area(s) of the structure, the area(s) is/are facing to the beam (1).

Abstract: Disclosed is an imaging system capable of reducing the generation of interference patterns in a state in which a beam of highly coherent electromagnetic waves is enlarged to a prescribed illumination area and used for illumination by moving the prescribed illumination region within a range of motion that is smaller than the illumination region.

Abstract: Provided is an imaging system, including: a light source; an imaging device; a first optical system for irradiating an imaging object with light from the light source; a second optical system for causing one of light reflected from the imaging object and light transmitted through the imaging object to enter the imaging device; a control device for controlling the light source to irradiate the light with a predetermined period; and a processing device for acquiring time-series image data over a plurality of frames by controlling the light source to irradiate the light with the predetermined period, and allocating a maximum pixel intensity among the time-series pixel data of each pixel as pixel data of the each pixel to thereby obtain first image data when the light source irradiates the light.

Abstract: Provided is an imaging system, including: a light source; an imaging device; a first optical system for irradiating an imaging object with light from the light source; a second optical system for causing one of light reflected from the imaging object and light transmitted through the imaging object to enter the imaging device; a control device for controlling the light source to irradiate the light with a predetermined period; and a processing device for acquiring time-series image data over a plurality of frames by controlling the light source to irradiate the light with the predetermined period, and allocating a maximum pixel intensity among the time-series pixel data of each pixel as pixel data of the each pixel to thereby obtain first image data when the light source irradiates the light.

Abstract: A vacuum cleaner includes a vacuum cleaner body in which a rotating brush, a dust collecting unit and an electric blower unit are integrally attached to a suction opening casing in which a brush chamber is formed. A rodlike handle is connected to the vacuum cleaner body. The rodlike handle is formed by a hollow member, and a plurality of batteries are arranged in series in the hollow member and are covered with a heat contraction tube.