Simple and cost-effective immersion method for freeform optical surface (FFS) measurements is proposed. Method is based on the determination of the borderline curve formed between the contacted immersion liquid and the controlled surface. Proposed method is suitable for measuring polished and rough surfaces, convex and concave freeform, aspheric, spherical surfaces, prisms and another optical and non-optical 3D objects having freeform surface.
The novel design for the compact augmented reality (AR) glasses that utilize holographic optical element (HOE) as a combiner is presented. The wide field of view (FoV) that is larger than 90°, full color and high contrast ratio (CR) are achieved based on the single layer HOE, which has the thickness of 25 μm. In order to implement compactness of AR glasses using HOE combiner, the combination of optical lenses is proposed. In this design, a chromatic aberration and astigmatism, which are caused by highly off-axis projection of the image onto HOE, and the precise wavefront reproduction that maximize the efficiency of the HOE are taken into account simultaneously. The geometrical image distortion is corrected by implementation of image pre-distortion algorithm. The interpupillary distance (IPD) adjustment is applied to compensate small eye box. Based on the design, wearable prototype is introduced. Through the experiments both on benchtop and prototype, at the distance of 2 m, large image with diagonal of 150 inches is displayed.
Nowadays, the main directions of augmented reality (AR) glasses development are: increasing of field of view (FoV) and eye-motion box; reducing weight of AR glasses; solving vergence-accomodation conflict. All these requirements should be obtained and combined with high image quality and decreasing dimensions of AR Glasses. We propose the optical system of AR glasses based on Schmidt Camera scheme for achievement of wide FoV and eye-motion box, and with using of Super Multi-View (SMV) technique for providing multifocal system. Provided optical design has huge benefits: eye motion box about 10 mm and field of view 60° and represents lightweight, eye fatigue free solution with low aberrations. Finally, our system has high opportunities for further modifications and improvements by using different image sources and projection system.
An optical system of a Schmidt-type telescope for orbital detection is proposed. The system contains a spherical mirror and correction plate with one aspherical surface and has the following characteristics: field of view (FoV) is 40 deg, entrance pupil diameter is 2.5 m, diameter of spherical mirror is 4 m, and f-number is 0.74. The system with the described parameters has image spot size of 3.2-mm (RMS) diameter for the axial beam and 4 mm (RMS) on the edge of the FoV, which is less than the diagonal of the detectors square pixel of 3×3 mm2.
A novel miniaturized near-infrared spectrometer readily mountable to wearable devices for continuous monitoring of individual’s key bio-markers was proposed. Spectrum is measured by sequential illuminations with LED’s, having independent spectrum profiles and a continuous detection of light radiations from the skin tissue with a single cell PD. Based on Tikhonov regularization with singular value decomposition, a spectrum resolution less than 10nm was reconstructed based on experimentally measured LED profiles. A prototype covering first overtone band (1500-1800nm) where bio-markers have pronounced absorption peaks was fabricated and verified of its performance. Reconstructed spectrum shows that the novel concept of miniaturized spectrometer is valid.
Non-contact methods for testing of large rotationally symmetric convex aspheric mirrors are proposed. These methods
are based on non-null testing with side illumination schemes, in which a narrow collimated beam is reflected from the
meridional aspheric profile of a mirror. The figure error of the mirror is deduced from the intensity pattern from the
reflected beam obtained on a screen, which is positioned in the tangential plane (containing the optical axis) and
perpendicular to the incoming beam. Testing of the entire surface is carried out by rotating the mirror about its optical
axis and registering the characteristics of the intensity pattern on the screen. The intensity pattern can be formed using
three different techniques: modified Hartman test, interference and boundary curve test. All these techniques are well
known but have not been used in the proposed side illumination scheme. Analytical expressions characterizing the shape
and location of the intensity pattern on the screen or a CCD have been developed for all types of conic surfaces. The
main advantage of these testing methods compared with existing methods (Hindle sphere, null lens, computer generated
hologram) is that the reference system does not require large optical components.