CGH generator and display apparatus including the same

A holographic display apparatus comprising:

• a light source;
• a spatial light modulator configured to modulate light from the light source according to an image to be displayed on an object plane;
• and
• a processor configured to generate a computer generated hologram (CGH) in which a phase value of hologram data to be displayed on a reference plane of the spatial light modulator is 0, the processor being configured to apply a light modulation signal based on the CGH to the spatial light modulator,
• wherein the processor is further configured to:
• repeatedly change an amplitude value of the hologram data to be displayed on the reference plane;
• obtain a complex function by propagating the repeatedly changed amplitude value toward the object plane;
• and
• search for a value via which an amplitude of the complex function becomes equal to an amplitude value of hologram image data to be displayed on the object plane.

A holographic display apparatus comprising:

• a light source;
• a spatial light modulator configured to modulate light from the light source according to an image to be displayed on an object plane;
• and
• a processor configured to generate a computer generated hologram (CGH) in which a phase value of hologram data to be displayed on a reference plane of the spatial light modulator is 0, the processor being configured to apply a light modulation signal based on the CGH to the spatial light modulator,
• wherein the processor is further configured to search for a complex function of the object plane, via which the phase of the hologram data to be displayed on the reference plane of the spatial light modulator becomes 0, according to an iterative Fourier transform algorithm (iFTA) method.

A holographic display apparatus comprising:

• a coherent light source;
• an amplitude modulation spatial light modulator (SLM) configured to modulate coherent light incident from the coherent light source;
• and
• a processor configured to:
• receive object amplitude data of an image to be displayed at an object plane;
• calculate object phase data of the image to be displayed at the object plane such that reference phase data of a computer generated hologram (CGH) applied to the amplitude modulation SLM is substantially equal to zero;
• generate the CGH comprising the reference phase data;
• and
• apply the CGH to the amplitude modulation SLM to display the image at the object plane,
• wherein the calculating the object phase data comprises:
• generating a first complex function comprising an initial arbitrary value as the object phase data;
• and
• performing an iterative process comprising:
• generating a second complex function by propagating the first complex function to a reference plane of the amplitude modulation SLM;
• determining whether phase data of the second complex function is substantially equal to zero;
• and
• based on the phase data of the second complex function not being substantially equal to zero, generating a third complex function comprising corrected phase data based on the phase data of the second complex function and repeating the iterative process using the third complex function as the first complex function.