Galina E. Romanova

Virtual-display optical devices

Modern optical systems of virtual displays are organized on various principles, including holographic, geometrical, and diffraction. This article discusses the most widely used types and features of these systems.

Using prism elements to construct flat waveguide screens

This paper discusses questions of the design of structured optical systems with a periodically repeated group of elements in the form of rhomb–prisms for transmitting an image from a microdisplay to the observer’s eyes. Recommendations are given for selecting the parameters of the prism elements that make up the waveguide screen.

Systems design of augmented-reality collimator displays

This paper describes the optical systems of helmet-mounted augmented-reality displays. Designs are presented that are based both on a nonplanar combiner and a flat combiner that brings a supplementary image into coincidence with an image of ambient space. Examples of systems are given for various implementations that use an opaque image generator.

Double degree master program: Optical Design

Modern tendencies of higher education require development of master programs providing achievement of learning outcomes corresponding to quickly variable job market needs. ITMO University represented by Applied and Computer Optics Department and Optical Design and Testing Laboratory jointly with Warsaw University of Technology represented by the Institute of Micromechanics and Photonics at The Faculty of Mechatronics have developed a novel international master double-degree program “Optical Design” accumulating the expertise of both universities including experienced teaching staff, educational technologies, and experimental resources. The program presents studies targeting research and professional activities in high-tech fields connected with optical and optoelectronics devices, optical engineering, numerical methods and computer technologies. This master program deals with the design of optical systems of various types, assemblies and layouts using computer modeling means; investigation of light distribution phenomena; image modeling and formation; development of optical methods for image analysis and optical metrology including optical testing, materials characterization, NDT and industrial control and monitoring. The goal of this program is training a graduate capable to solve a wide range of research and engineering tasks in optical design and metrology leading to modern manufacturing and innovation. Variability of the program structure provides its flexibility and adoption according to current job market demands and personal learning paths for each student. In addition considerable proportion of internship and research expands practical skills. Some special features of the “Optical Design” program which implements the best practices of both Universities, the challenges and lessons learnt during its realization are presented in the paper.

Designing and researching of the virtual display system based on the prism elements

Problems of designing of systems for virtual display systems for augmented reality placed near the observers eye (so called head worn displays) with the light guide prismatic elements are considered. Systems of augmented reality is the complex consists of the image generator (most often it’s the microdisplay with the illumination system if the display is not self-luminous), the objective which forms the display image practically in infinity and the combiner which organizes the light splitting so that an observer could see the information of the microdisplay and the surrounding environment as the background at the same time. This work deals with the system with the combiner based on the composite structure of the prism elements. In the work three cases of the prism combiner design are considered and also the results of the modeling with the optical design software are presented. In the model the question of the large pupil zone was analyzed and also the discontinuous character (mosaic structure) of the angular field in transmission of the information from the microdisplay to the observer’s eye with the prismatic structure are discussed.

Method for calculation and analysis of a cemented component with achromatic and aplanatic correction

This paper presents a method for calculating and analyzing a cemented component, developed on the basis of the methodology of G. G. Slyusarev. According to the given values of the main parameters P, W, and C, which determine the aberration characteristics of the system, several suitable pairs of glasses are selected that provide the required values of the third-order aberrations. For each pair, the design parameters of the cemented component are calculated, and the residual aberrations are determined according to the calculation of the real ray path.

Design of single and two-lens laser flat-top reshaping systems

Recently laser technologies are expanded widely among various applications of optical devices. Regarding unique properties laser sources are used in industrial systems, in medicine, in a variety of laboratory equipment, etc. Large number of technical applications requires laser beam reshaping, which presuppose redistribution of optical power in the beam cross-section; particularly to form a flat-top beam with uniform intensity distribution. Traditional inverted lens telescopic systems purposed for the light collimation do not allow to achieve the laser beam reshaping. For this case is possible to use more complicated kind of lens surfaces, such as aspherical ones, or freeforms (both lens and mirror optical systems), microlens arrays and other approaches. Current work describes the optimization model of laser beam reshaping optical system based on aspherical (conic) optics, using Zemax software. Single and two-lens telescopic systems were investigated to reach specified characteristics, results of this studies are shown.

Optical schemes of the head-mounted displays

Recently there is a growing interest to the head up and head mounted systems. There are many variants of implementation of the head-mounted display system for various purposes with different characteristics. The configuration of the system is highly affected by both type of the image generator and the type of the used combiner. We have considered several variants of the layout of the systems and compare their characteristics including the package and image quality. The systems were designed for operating with the same image generator.

Analysis of the three-mirror systems for survey telescopes

Normally, telescope systems applied for astronomic purposes have rather narrow field. Survey telescopes which are the systems with angular field up to several degrees are applied in several spheres not only for astronomic purposes but also for weather observing, comets and asteroids detecting (asteroid and comet threats or ACT). Systems with relatively small diameters (below 1.5m) are of interest both for ground-based and space instruments. As a rule, such systems should be fast (up to F/3 … F/1.5 and faster). Therefore, the most part of survey telescopes are reflective systems with additional lens correctors. Lens elements in these instruments can lead to some difficulties because the possibility of manufacturing large size lens correctors of the optimal glass sort is not always exist. So, from that point mirror systems can provide more advantages. Mirror systems are also of great interest due to the wide spectrum range used for operation. However, the design of the mirror system that can give both sufficient f-number and large angular field is the complicated and complex task, first of all because of difficulty during the choosing the initial principal scheme. Using the expressions based on the third-order aberration theory several system of survey telescopes were chosen which can provide the needed characteristics. The examples of the schemes are given, including their optical characteristics.

Analysis of ghost images in a compound prismatic combiner for head-up-displays

Systems of augmented reality are widely used not only in military but and in civil application. Providing a sufficient size for the pupil zone, which is the area where the user’s eye could be located, may be implemented in different ways. One of the ways is to multiply (duplicate) the pupil using a beam-splitting with special coating or elements, for example with semi-transparent layers. This method is very attractive because it can provide the most compact schemes. The compound prismatic combiner which uses waveguide principle is considered and analyzed in the work. It was shown in previous work that the angles of the entrance prism and layers should be chosen in certain limits to provide beam passing through the structure due to total internal reflection, partially reflected by beam-splitting layers. This structure has mosaic structure of the pupil zone that means appearing the dark zones where the part of an image does not exist. To minimize dark zones the structure step should be minimal but the ghost images may appear. Dark zones size and brightness of the ghosts are dependent on the combiner’s parameters, so we can find optimal case as a compromise between the dark zone size and ghost image. Analysis of the ghosts’ brightness was implemented, and optimal locations of the observer’s eye and optimal structure parameters were found from the point of view of minimizing ghosts for the system with the smallest blind zone sizes.