Holographic display apparatus and method for providing expanded viewing window

A holographic display method comprising:

• providing a computer generated hologram (CGH) signal to a spatial light modulator to generate a holographic image;
• providing the holographic image to an input coupler of a light guide plate;
• and
• reproducing, on an image plane, the holographic image which is propagated inside the light guide plate and is output through an output coupler of the light guide plate,
• wherein the providing of the CGH signal to the spatial light modulator comprises:
• converting source image data based on a point spread function, which is obtained using an image processor for each pixel of the holographic image on the image plane, to compensate for a blur of the holographic image output through the output coupler;
• and
• obtain a CGH based on the converted source image data.

A holographic display apparatus comprising:

• a light guide plate comprising an input coupler and an output coupler, a size of the output coupler being greater than a size of the input coupler;
• a holographic image generating assembly configured to generate a holographic image and provide the holographic image to the input coupler of the light guide plate;
• and
• an image processor configured to convert source image data having a depth information based on a matrix that is previously obtained and stored.