Patent ID: 7113316

Claim:
A holographic optical element comprising: a diffraction surface that diffracts an incident light beam, said diffraction surface having in at least its part a holographic pattern having the function of twisting said diffracted light beam using the optical axis of the diffracted light beam as an axis of rotation; wherein said diffraction surface is divided into a first region and a second region, at least one of said first and second regions having said holographic pattern; wherein said first region has a first holographic pattern having the function of twisting said diffracted light beam in one direction using the optical axis of the diffracted light beam as an axis of rotation, and said second region has a second holographic pattern having the function of linearly twisting, without distorting said diffracted light beam in said one direction using the optical axis of the diffracted light beam as an axis of rotation, according to a linear shift in the position of said object from a focal point of said light beam.