ABSTRACT
In this paper we present an infrared laser pointer, consisting of a vertical-cavity surface-emitting laser (VCSEL) and a diffractive optical element (DOE), encapsulated into a scleral contact lens (SCL). The VCSEL is powered remotely by inductive coupling from a primary antenna embedded into an eyewear frame. The DOE is used either to collimate the laser beam or to project a pattern image at a chosen distance in front of the eye. We detail the different SCL constitutive blocks, how they are manufactured and assembled. We particularly emphasize the various technological challenges related to their encapsulation in the reduced volume of the SCL, while keeping the pupil free. Finally, we describe how the laser pointer operates, what are its performances (e.g. collimation, image formation) and how it can be used efficiently in various application fields such as visual assistance and augmented reality.
ABSTRACT
We present a new eye-tracking and target designation device based on a contact lens incorporating a pair of vertical-cavity surface-emitting lasers (VCSELs). We describe the operating principle, the manufacturing process and characterize the impact of the VCSELs encapsulation on their optical properties. We then describe how such device can be incorporated into an eye-wear or a visual augmented system. We compare two different detection set-ups, the first using a camera and the second a position sensitive device, both illustrating different laser beam detection modes. We analyze their performances in terms of angular accuracy, speed, compactness, manufacturability, compared to current conventional eye-tracking systems. We emphasize how the use of two VCSELs and the control of their orientation during the encapsulation can simplify their integration in host systems and improve the gaze detection performance. Finally, we describe various embodiments and discuss potential improvements that can be expected in future systems.
Subject(s)
Contact Lenses , Eye-Tracking Technology , Lasers , LightABSTRACT
Most eye trackers nowadays are video-based, which allows for a relatively simple and non-invasive approach but also imposes several constraints in terms of necessary computing power and conditions of use (e.g., lighting, spectacles, etc.). We introduce a new eye tracker using a scleral lens equipped with photodiodes and an eyewear with active illumination. The direction of gaze is obtained from the weighted average of photocurrents (centroid) and communicated through an optical link. After discussing the optimum photodiodes configuration (number, layout) and associated lighting (collimated, Lambertian), we present prototypes demonstrating the high performances possibilities (0.11° accuracy when placed on an artificial eye) and wireless optical communication.
Subject(s)
Biosensing Techniques/instrumentation , Contact Lenses , Eye-Tracking Technology , Equipment Design , Humans , ScleraABSTRACT
A new mixed-valent iron ammonium phosphate, beta-NH(4)Fe(2)(PO(4))(2), has been synthesized. The diffuse scattering observed on the diffraction patterns implies complex disorder phenomena and prevents a direct structure resolution. The latter can be solved by generating an artificially ordered orthorhombic structure, using a five-dimensional approach and performing partial integration of the diffuse streaks. In the artificially ordered structure, hexagonal tunnels, delimited by FeO(6) octahedra, perpendicular to the directions [011] and [01(over)1] can then be seen; they are filled either by [FeP(2)O(10)](infinity) zigzag ribbons or by NH(4)(+) cations. It is shown that the disordering originates from the shifting of adjacent (100) tunnel slices of the structure with respect to each other along [011], allowing the formation of either new commensurate (superstructure) or incommensurate modulations, or even complete disorder along a. The close relationships with the ordered monoclinic form alpha-NH(4)Fe(2)(PO(4))(2) are also explained by this description.
