Vadim V. Smirnov

Non-glasses type stereoscopic display system based on polarization

The problems related with a dichroic type polarization filter plate which is used as a spatial image separator for a non-glasses type stereoscopic display device utilizing a liquid crystal display panel are discussed. The filter plate is consisted of many parallel line filters. Each line filter is directing the light with the same polarization only to its corresponding pixel lines in the display panel. The filter plate is cemented to the display panel, back- illuminated by a halogen lamp through two cross-polarized polarizers in side by side. Two Fresnel lenses located before the filter plate for collimating the illuminating beam and after the liquid crystal display panel for forming the images of two polarizers in front of the liquid crystal display panel as viewing zones are used.

Real-time 3D display with acousto-optical deflectors

A laser volumetric display system based on the sequential scanning of 2D images on a rotating diffusing screen is introduced. The system can generate volume imags having a dimension of 120 X 120 X 100 mm3 with 250,000 resolvable volume pixels. The images are displayed with the frame rate of 15 to 25 Hz. The distance between the projection objective and the screen is 3m. The volumetric images generated by the system are clear and sharp.

Multi - viewing zone screen for multiview 3-D displays

A new type of multi-viewing zone screen for multiview 3-D display is described. The screen is made by stacking a Fresnel lens and a reflective prism array plate. The screen performs both focusing and beam dividing functions and directs very narrow light beams to three viewing zones for three spectators. The results of experimental testing of the screen have demonstrated that current technology of Fresnel lens and prism grooves on PMMA(Ploymethyl Methacrylate) allows manufacture of screen having a pixel size of about 1-2 mm. This size is reasonable enough for a screen with dimensions about 1m size. Optical qualities of Fresnel lenses and grooved prism arrays achieve an angular resolution for the screen of several angular minutes.

Holographic screens and their applications

The holographic screen is an unique image projecting screen for 3D image display. It can be made to display full color images by several different techniques. It is also possible to make the holographic screen having size more than 1 m by mosaicking small size screens. The full color holographic screen is highly transparent. This characteristic can lead the holographic screen to be used in art and the head up displays for cars.

Achromatized holographic screen for multiview TV display

A chromatically corrected reflective holographic screen is made by stacking two holographic plates with focused mirror properties. This screen has the properties of three equal power spherical mirrors by recording two spherical mirrors on one of the plates. Each of these mirrors is tuned to a corresponding CRTs spectral bandwidth centered at one of the wavelengths 450, 540 and 626 nm. The plate with two spherical mirrors are tuned and chirped its fringe structures to widen its bandwidths. An experimental sample with a dimension of 10 X 8 cm2 is recorded on DuPont photopolymer film, HRF- 706-20 such that the images of the exit pupil of a projectors objective by the three holographic spherical mirrors overlap together with a spatial resolution enough for 8-views image display. The image brightness on the screen is about 15 times of that on the standard white diffuser.

Characteristics of Reflection Type HOEs Measured Visually

The main parameters of defining the characteristics of a reflection-type holographic optical element, such as diffraction efficiency, the wavelength of the maximum reflection, spectral and angular selectivity, and grating vector directions are measured with a wide angle diverging beam incident normal to the element. Dark ring patterns in the intensity distribution of the beam transmitted through the element allow visual determination of the parameter values. The features of the rings, such as size, shape, thickness, intensity distribution and direction of deviation relative to the center of the distribution are analyzed to determine the parameter values. The results are closely matched with those predicted theoretically.

Fabrication of Lens Rasters Using a Laser Beam Scanning Method

A cylindrical lens raster array is drawn on a dichromatic gelatine layer by hardening with a scanning laser beam. The thicknesses of the gelatine layer used for the array range from 40 to 80 µm. The laser beam intensity profile is modified by a mask with a specific transparency function to fabricate the desired lens profile. This method is used to produce lens rasters which can be used as 3-dimensional image projection screens and anamorphosers.

VISUAL METHOD OF MEASURING REFLECTION-TYPE CHARACTERISTICS OF HOLOGRAPHIC OPTICAL ELEMENTS

A highly diverging laser beam is used to measure angular and spectral selectivities and grating vector direction for reflection-type holographic optical elements (HOEs). The intensity distribution of the beam transmitted from the HOEs reveals dark, ring-shaped patterns. Since these ring patterns are formed as a result of the beam diffracted by the HOEs, the thicknesses and the diameters of the ring patterns convey information on both the angular and the spectral selectivities of the HOEs. In addition the deviation of the ring centers relative to the center of the intensity distribution reveals the grating vector direction. Determination of values related to the ring patterns permits highly accurate measurement of HOE characteristics, such as the upper limit of the diffraction wavelength, the angular and the spectral selectivities, and the grating vector direction. This is proved experimentally.