Multi-stack information carrier

An optical scanning device for scanning an information carrier (610) by means of an optical beam (602), said information carrier comprising at least two information stacks (611, 612), wherein each stack comprises a first electrode, a second electrode and an information layer between the first and second electrodes, wherein the information layer comprises molecules which can be rotated when a suitable potential difference is applied between the first and second electrodes, said optical scanning device comprising means (601) for generating the optical beam, means (603, 605) for focusing said optical beam on an information layer and means for applying a potential difference between the first and second electrodes of an information stack.

A method of reading information from an information carrier by means of an optical beam, said information carrier comprising at least two information stacks, wherein each stack comprises a first electrode, a second electrode and an information layer between the first and second electrodes, wherein the information layer comprises molecules which can be rotated when a suitable potential difference is applied between the first and second electrodes, said method comprising the steps of applying a potential difference between the first and second electrodes of the information stack from which information is to be read and focusing the optical beam on the information layer of said stack.

A method of recording information on an information carrier by means of an optical beam, said information carrier comprising at least two information stacks, wherein each stack comprises a first electrode, a second electrode and an information layer between the first and second electrodes, wherein the information layer comprises molecules which can be rotated when a suitable potential difference is applied between the first and second electrodes, said method comprising the step of focusing the optical beam on the first electrode of the information stack on which information is to be recorded in order to locally reduce the electrical conductance of the first electrode.

A method of recording information on an information carrier by means of an optical beam, said information carrier comprising at least two information stacks, wherein each stack comprises a first electrode, a second electrode and an information layer between the first and second electrodes, wherein the information layer comprises molecules which can be rotated when a suitable potential difference is applied between the first and second electrodes, said method comprising the step of focusing the optical beam on the information layer of the information stack on which information is to be recorded in order to locally degrade the information layer.

A method of recording information on an information carrier by means of an optical beam, said information carrier comprising at least two information stacks, wherein each stack comprises a first electrode, a second electrode and an information layer between the first and second electrodes, wherein the information layer comprises a matrix comprising two types of surface-charged colloidal particles, one with negative charge and one with positive charge (422, 423), said surface-charged colloidal particles comprising liquid crystal molecules, said matrix having a viscosity which can be locally reduced by means of an optical beam, said method comprising the steps of focusing the optical beam on the information layer of the information stack on which information is to be recorded in order to locally reduce the viscosity of the matrix of said information layer, and applying a potential difference between the first and second electrodes of said stack.