High efficiency backlight for multiscopic display

A system comprising:

• a liquid crystal display (LCD) device comprising:
• a backlight unit;
• a first polarizer and a second polarizer having a first polarization orientation and a second polarization orientation, respectively, wherein the first polarizer is arranged between the backlight unit and the second polarizer;
• at least one liquid crystal (LC) layer arranged between the first polarizer and the second polarizer, the at least one LC layer comprising a plurality of LC cells;
• and
• a second drive circuit that is employed to individually control the plurality of LC cells of the at least one LC layer;
• an optical combiner arranged on an optical path of the liquid crystal display device and on an optical path of a real-world light field of a real-world environment;
• tracking means;
• and
• at least one processor configured to:
• generate drive signals for controlling the plurality of LC cells of the at least one LC layer;
• and
• send the drive signals to the second drive circuit,
• wherein the plurality of LC cells of the at least one LC layer are controlled individually by the second drive circuit using the drive signals, to adjust a polarization of light passing therethrough for producing a synthetic light field, and wherein the optical combiner is configured to reflect the synthetic light field towards eyes of at least one user, while optically combining the real-world light field with the synthetic light field;
• wherein the at least one LC layer comprises a first LC layer and a second LC layer that are arranged between the first polarizer and the second polarizer, the second LC layer being arranged between the first LC layer and the second polarizer, and wherein the first LC layer and the second LC layer have a gap therebetween,
• wherein the at least one processor is further configured to:
• utilise the tracking means to determine a relative location of a first eye and of a second eye of the at least one user with respect to an image plane of the LCD device;
• generate or obtain a first virtual image and a second virtual image to be presented to the first eye and the second eye of the at least one user, respectively, based on the relative location of the first eye and of the second eye of the at least one user with respect to the image plane of the LCD device;
• and
• when generating the drive signals, generate drive signals for controlling LC cells of the first LC layer and LC cells of the second LC layer based on the first virtual image, the second virtual image, and the relative location of the first eye and of the second eye of the at least one user with respect to the image plane of the LCD device,
• wherein the synthetic light field presents the first virtual image and the second virtual image to the first eye and the second eye of the at least one user, respectively, and
• wherein, when generating the drive signals, the at least one processor is configured to:
• for a given LC cell of the second LC layer, determine a first viewing direction and a second viewing direction from which the first eye and the second eye view the given LC cell of the second LC layer, respectively, based on a location of the given LC cell in the second LC layer and the relative location of the first eye and of the second eye of the at least one user with respect to the image plane of the LCD device;
• determine a first LC cell and a second LC cell of the first LC layer that lie along the first viewing direction and the second viewing direction, respectively;
• determine a first pixel location of a given first pixel of the first virtual image based on the first viewing direction and the relative location of the first eye with respect to the image plane of the LCD device;
• determine a second pixel location of a given second pixel of the second virtual image based on the second viewing direction and the relative location of the second eye with respect to the image plane of the LCD device;
• fetch, from the first pixel location in the first virtual image, a first intensity value of the given first pixel of the first virtual image;
• fetch, from the second pixel location in the second virtual image, a second intensity value of the given second pixel of the second virtual image;
• and
• generate respective drive signals for the given LC cell of the second LC layer, the first LC cell of the first LC layer, and the second LC cell of the first LC layer based on the first intensity value of the given first pixel of the first virtual image and the second intensity value of the given second pixel of the second virtual image.