Patent ID: 6886177

Claim:
A phase-change type optical information recording medium comprising: a transparent substrate; a first protective layer on the substrate; a recording layer on the first protective layer; a second protective layer on the recording layer; and a reflective layer on the second protective layer, wherein the recording layer includes as a main component Ag α In β Sb γ Te δ where α, β, γ, and δ represent atomic percents and satisfy the relations: 0.1≦α≦2.0, 3.0≦β≦8.0, 65.0≦γ≦75.0, 15.0≦δ≦30.0, and 97≦α+β+γ+δ≦100; and wherein assuming that a minimum recording linear velocity to be V 1 , a maximum recording linear velocity to be V 2 , and a degree of modulation at the time of reading out information to be I(V), then a value of I(V 2 )/I(V 1 ) is within a range from 1 to 1.2.