To provide a device and a method for preventing, improving, or preventing a worsening of depression by irradiating light having specific wavelengths, such as violet light, as well as a method for operating the device.
The above-described problem is solved by a device and a method used for the purpose of preventing, improving, or preventing a worsening of depression by irradiating a subject with violet light having a wavelength within a range of 360 to 400 nm. An operating method of a device is a method for operating a device including irradiation means for irradiating a subject with violet light having a wavelength within a range of 360 to 400 nm and used for the purpose of preventing, improving, or preventing a worsening of depression. The operating method comprises operating the irradiation means of the device by changing, by transmission and reception with an isolation controller such as a mobile terminal, one or two or more irradiation conditions selected from an irradiation state (including continuous light or blinking frequency), an irradiance, an irradiation time, an irradiation start time, an irradiation end time, and continuous light or a blinking frequency.