An optical disk includes a first substrate provided with a first minute
concaves/convexes forming a CD signal and a second substrate provided with
a second minute concaves/convexes forming a DVD signal, and a wavelength
selective multi-layered film is formed on the second minute
concaves/convexes by laminating titanium dioxide films and silicon dioxide
films approximately fifteen (15) layers. Due to the wavelength selective
multi-layered film, a laser beam which reproduces the CD signal is
transmitted by a transmissivity of more than 80%, and a laser beam which
reproduces the DVD signal is reflected by a reflectivity of more than 80%.
