Blu-ray discs are the third generation of optical discs intended for the storage of digital data. Data is stored in the spiral-shaped track 0.1 mm below the surface of the disc, with a lateral stop distance of 0.35 micron. Laser light is used to read Blu-ray discs with a wavelength of 405 nm. Technology was developed by the Japanese company Sony, with other firms like Philips being involved also. The name Blue-ray is associated with the color of light used for reading the data.