Abstract: 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%.

Abstract: In a method of producing a lightguide plate for surface light source according to the present invention, a plate-shaped metal mold for defining the shape of a part of a cavity of a molding die and particularly, the shape of a light emitting surface of the lightguide plate for surface light source (a concavo-convex shape, a lenticular lens shape, etc.) is provided so as to be replaceable, to form a cavity having a desired shape by the replacement of the plate-shaped metal mold. Resin liquid is injected into the cavity, its resin liquid is solidified, and the resin is then released from the cavity. Consequently, a lightguide plate for surface light source having a desired shape and particularly, having its light emitting surface in a desired shape is produced.

Abstract: Two or three different signal recording regions are formed in one optical disk. One signal recording region is positioned at a depth of 0.6 mm from a disk surface and is formatted in accordance with a single layer or two layer DVD standard, for example. Remaining signal recording region is positioned at a depth of 1.2 mm from the disk surface and is formatted in accordance with the CD, CD-R or MO disk standard, for example. By using such an optical disk, whether a manufactured optical pickup device is capable of reproducing two or three different types of optical disks can be checked quickly.