2. The proposed system structure
In this section, the convectional structure and operation principle
of a traditional 3D imaging is first addressed. Fig. 1(a) shows
the schematic diagram of a two-view display with the conventional
lenticular lens sheet and composited images. Each cylindrical
lens covers approximately two pixels (the left and right images).
The composited image is formed with multi-pixels interlaced and
placed behind the lenticular lens. This lenticular sheet consists of
a linear array of thick plano-convex cylindrical lenses. By the principle
of refraction, the left and right images are projected onto the
viewer’s left and right eyes, respectively, in the horizontal direction.
Under this condition, a viewer can perceive a 3D imaging based on
the principle of binocular vision [15].
Following the review of the principle and structure of a 3D display,the
concept oftwo-view autostereoscopic display with anAOL
is shown in Fig. 1(b). TheAOL thatis proposed to replace the convectional
lenticular lens and can function according to the acouto-optic
principle, is placed in front of the display panel. By applying an
external radio frequency (RF) signalto the AOL through a piezoelectric
transducer, the electrical energy can be converted into acoustic
energy and produces an acoustic wave inside the acousto-optic
material and hence create a standing sound wave (acoustic profile
principle) inside the acousto-optic cell under the Bragg condition.
The positions of loop and nodes for standing acoustic wave inside
the AOL/AOL array are stationary. Therefore, a cylinder lens array
with adjustable focal length and lens pitch can then be formed
inside the AOL crystal. A periodic change of refractive index occurs
inside the AOL crystal due to the interaction between standing
acoustic wave and acousto-optic material inside the crystal and
hence creates a lens or lens array with the focal length and/or the
pitch of the lenses that are adjustable through the tuning of the
amplitude/power and frequency of the external acoustic wave.