Holographic display apparatus, head-up display apparatus, and image providing method

A holographic display apparatus comprising:

• a backlight unit comprising a light source configured to emit coherent light
• a spatial light modulator configured to diffract incident light from the backlight unit and generate a holographic image;
• a beam deflector configured to change a traveling direction of the incident light from the backlight unit to change a focal position of the holographic image;
• an eye-tracking sensor configured to recognize positions of a viewer's eyeballs;
• and
• a controller configured to perform, in real time, calibration of the eye-tracking sensor and the beam deflector to focus the holographic image on the recognized positions of the viewer's eyeballs;
• an infrared light source configured to emit infrared rays to be incident upon the beam deflector or the spatial light modulator;
• and
• an infrared sensor configured to sense an image generated by the infrared rays emitted from the infrared light source and reproduced by the beam deflector and the spatial light modulator,
• wherein the controller is further configured to perform, in real time, calibration of the eye-tracking sensor and the beam deflector based on the image sensed by the infrared sensor
• wherein the controller is further configured to calculate position coordinates at which a primary image of the holographic image is focused based on the image obtained by the eye-tracking sensor or the infrared sensor, the primary image being generated by first order diffracted light.

An image providing method using a display apparatus, the display apparatus comprising an image generating apparatus, a beam deflector configured to change a traveling direction of light from the image generating apparatus, and an eye-tracking sensor configured to recognize positions of a viewer's eyeballs, the image providing method comprising:

• sensing a first position of the viewer's eyeballs using the eye-tracking sensor;
• providing an image generated using the image generating apparatus to the viewer's eyeballs;
• sensing a position at which the image is focused;
• and
• performing, in real time, mutual calibration of the eye-tracking sensor and the beam deflector based on the first position and the position at which the image is focused.

A head-up display apparatus configured to project an image on a windshield providing an external view to a driver, the head-up display apparatus comprising:

• a display apparatus comprising an image generating apparatus and an eye-tracking sensor configured to recognize the driver's eyeballs;
• an optical system configured to project the image from the display apparatus on the windshield;
• and
• a beam deflector configured to change a traveling direction of incident light from the image generating apparatus to change a position at which the image is focused,
• wherein the display apparatus further comprises a controller configured to perform, in real time, calibration of the eye-tracking sensor and the beam deflector to focus the image on positions of the driver's eyeballs, the positions being recognized by the eye-tracking sensor,
• wherein the controller is further configured to compare a first position of the driver's eyeballs, the first position recognized by the eye-tracking sensor, with a second position at which the image is focused, and control an operation of the beam deflector to change the second position such that a distance between the first position and the second position is less than or equal to a critical distance, and
• wherein the controller comprises a memory in which a look-up table (LUT) formed in advance is stored, the LUT matching first data related to the first position with second data related to the second position.