Patent attributes
In a display device, when blue (B) light enters a first liquid crystal panel, radiated light radiated from the first liquid crystal panel contains red (R) phosphorescence having a wavelength range longer than blue (B) light due to a deterioration of a liquid crystal material. Thus, in the display device, an optical sensor device is provided behind a mirror comprised of a dichroic mirror to monitor or the like the service life of the first liquid crystal panel on the basis of a result of reception, at the optical sensor device, of light having a frequency band ranging from 600 nm to 650 nm, and makes notification of the result. Furthermore, on the basis of a result from the optical sensor device, an electrode used to suck impurities provided at the first liquid crystal panel is driven to sweep ionic impurities from a display region.