Information recording medium, information recording method, and information reproduction method

An information recording method that records information using an arrangement of a plurality of micro-denatured regions formed by irradiating an inside of a light-transmitting medium with a pulsed laser beam, the information recording method comprising:

• a recording step of forming the micro-denatured regions in each of a first layer and a second layer inside the information recording medium, wherein
• in the recording step, the micro-denatured regions are formed at a plurality of positions corresponding to a plurality of lattice points on a two-dimensional plane orthogonal to a thickness direction of the information recording medium in each of the first layer and the second layer,
• in the recording step, the micro-denatured regions formed in the first layer and the micro-denatured regions formed in the second layer are formed such that positions of the micro-denatured regions differ from each other when projected onto the two-dimensional plane, and
• in the recording step, the micro-denatured regions are formed such that all positions on the lattice points of the micro-denatured regions formed in the first layer do not overlap with any positions on the lattice points of the micro-denatured regions formed in the second layer.

An information reproduction method that reproduces information recorded in an information recording medium that records the information using an arrangement of a plurality of micro-denatured regions formed by irradiating an inside of a light-transmitting medium with a pulsed laser beam, wherein

• the micro-denatured regions are formed in each of a first layer and a second layer inside the information recording medium,
• the micro-denatured regions are formed at a plurality of positions corresponding to a plurality of lattice points on a two-dimensional plane orthogonal to a thickness direction of the information recording medium in each of the first layer and the second layer,
• the micro-denatured regions are formed such that all positions on the lattice points of the micro-denatured regions formed in the first layer do not overlap with any positions on the lattice points of the micro-denatured regions formed in the second layer, and
• the information reproduction method comprises:
• a step of irradiating illumination light onto the information recording medium from a direction not orthogonal to the first layer and the second layer;
• a step of capturing the information recording medium irradiated with the illumination light with an image capturing device;
• and
• a step of reproducing the information from an image captured with the image capturing device.