US Patent 7796495 Optical disk

An optical disk comprising two layers including a signal recording layer and an image recording layer further comprises a metal reflective layer formed on a surface of the image recording layer on the incidence side of laser light. The image recording layer is capable of forming a visible image in response to an increase in temperature caused by application of laser light to the metal reflective layer. The visible image is capable of being visually observed from a side opposite to the incidence side.