OPTICAL RECORDING MEDIUM AND OPTICAL INFORMATION DEVICE Russian patent published in 2013 - IPC G11B7/24 G11B7/252 

FIELD: physics.

SUBSTANCE: recording medium has three recording surfaces, a coating layer and two intermediate layers. Thicknesses tr1, tr2 and tr3 of the coating layer, first intermediate layer and second intermediate layer, respectively, are converted to thicknesses t1, t2, t3 of corresponding layers, each having a predefined standard refraction index no, based on the equation tα=trα*(tan(θrα)/tan(θo)), where θrα and θo are angles of convergence of light in the layer, having each refraction index nrα and standard refraction index no. Thicknesses t1, t2 and t3 satisfy the condition |t1-(t2+t3)| ≥ 1 mcm. The difference between any two values of thicknesses t1, t2 and t3 is set equal to or greater than 1 mcm in any case.

EFFECT: preventing formation of an image on the rear surface of the optical recording medium and suppressing coherence between reflected light from recording surfaces.

2 cl, 13 dwg