A large angle, low voltage, small footprint micromirror for eye tracking and near-eye display applications

Sarkar, Niladri; Strathearn, D.; Lee, G.; Olfat, M.; Rohani, Arash; Mansour, Raafat R.

doi:10.1109/transducers.2015.7181058

Cited by 17 publications

(5 citation statements)

References 4 publications

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“…These tasks have been used widely in eye movement studies; however, the capability of the MindLink system remains to be examined in other tasks where participants are not constrained by a chin rest and the stimulus is presented in more ecological conditions rather than a computer monitor. Finally, the application of MEMS technology to eye tracking is quite novel [ 37 ]. While the current tracking algorithms provide less accurate recordings when compared to the EyeLink eye tracker, it is likely that as the technology matures the tracking algorithms will also improve.…”

Section: Discussionmentioning

confidence: 99%

Investigation of Camera-Free Eye-Tracking Glasses Compared to a Video-Based System

Zafar,

Calderon,

Yeboah

et al. 2023

Sensors

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Technological advances in eye-tracking have resulted in lightweight, portable solutions that are capable of capturing eye movements beyond laboratory settings. Eye-tracking devices have typically relied on heavier, video-based systems to detect pupil and corneal reflections. Advances in mobile eye-tracking technology could facilitate research and its application in ecological settings; more traditional laboratory research methods are able to be modified and transferred to real-world scenarios. One recent technology, the AdHawk MindLink, introduced a novel camera-free system embedded in typical eyeglass frames. This paper evaluates the AdHawk MindLink by comparing the eye-tracking recordings with a research “gold standard”, the EyeLink II. By concurrently capturing data from both eyes, we compare the capability of each eye tracker to quantify metrics from fixation, saccade, and smooth pursuit tasks—typical elements in eye movement research—across a sample of 13 adults. The MindLink system was capable of capturing fixation stability within a radius of less than 0.5∘, estimating horizontal saccade amplitudes with an accuracy of 0.04∘± 2.3∘, vertical saccade amplitudes with an accuracy of 0.32∘± 2.3∘, and smooth pursuit speeds with an accuracy of 0.5 to 3∘s, depending on the pursuit speed. While the performance of the MindLink system in measuring fixation stability, saccade amplitude, and smooth pursuit eye movements were slightly inferior to the video-based system, MindLink provides sufficient gaze-tracking capabilities for dynamic settings and experiments.

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Section: Discussionmentioning

confidence: 99%

Investigation of Camera-Free Eye-Tracking Glasses Compared to a Video-Based System

Zafar,

Calderon,

Yeboah

et al. 2023

Sensors

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show abstract

“…Also, photodiodes on smart contact lenses combined with IR LEDs on eyeglasses were also used for eye tracking [50]. Another application of a VCSEL-based system in eye tracking involves light from VCSELs directed with a micromirror onto the eye and detected with photodiodes for smart eyeglasses [51]. Purkinje reflections is yet another method used for eye tracking [52].…”

Section: Distance Sensing From Eye Vergence Triangulatonmentioning

confidence: 99%

Ultralow Power On-the-Eye Vergence and Distance Sensing Through Differential Magnetometry

et al. 2023

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We demonstrate the realization of a very low energy, on-the-eye vergence-type distance ranger based on sensing of a locally-uniform vector field, specifically the earth's magnetic field. This ranging method is passive, only requiring measurement of the magnetic field vector at both eyeballs utilizing magnetometer chips placed on the eye scleral regions. The eye vergence angle and range distance are calculated from these two vector quantities. The method can obtain a range reading with as little as 118 nJ of energy consumed per eye for 3.3V and 50 nJ when operated at 1.9V. This method is thus suitable for applications where energy storage is very limited such as in smart contacts vision correcting microsystems.

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“…These selections provide a rectangular scan area in front of the vehicle with a refresh rate of about 50 Hz. This scanning method is rarely used in LiDAR systems compared with the more common raster scanning, 5,7,8 in which one axis is fast and the other axis is slow. When both axes are driven with only a small frequency difference between them, the resulting almost uniform XY-movement enables measurements evenly around the scan area.…”

Section: Mems Mirror Designmentioning

confidence: 99%

“…Various methods have been applied to miniaturize the optical scanning elements of the LiDAR system, such as the two-mirror systems presented by Wang et al 1 and Nguyen et al 2 or the wobbling mirror for circular scanning presented by Pensala et al 3 and Hoffman et al 4 This work is concentrated on a single-mirror approach for a 2D-scanning pattern suitable for use in forward-looking LiDARs. Different types of 2D-scanning LiDARs have been reported based on PZT-elements 5 and electrothermal, 6,7 electromagnetic, 8 or electrostatic actuators. 9 Actuators fabricated on the aluminium nitride (AlN) thin-film-based process offer comparable performance levels with other state-of-the-art 2D scanning techniques, in which the tilt angle and the mirror size are mainly limited by mechanical considerations.…”

Section: Introductionmentioning

confidence: 99%

Resonating AlN-thin film MEMS mirror with digital control

Ruotsalainen

Morits

Ylivaara

et al. 2022

J. Optical Microsystems

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Piezoelectrically actuated resonant micromirrors were designed to meet the light detection and ranging (LiDAR) system requirements. Key features were a 3-mm mirror aperture, a 40-deg field of view, and a 50-Hz refresh rate. The presented micromirror provides biaxial symmetrical beam steering with AE12.7 deg mechanical tilt angle, resulting in a 50-deg field of view with an adjustable Lissajous XY-scanning pattern for a forward-looking LiDAR system. The mirrors were fabricated using silicon on insulator wafers, and actuation was based on piezoelectric aluminium nitride thin film. The mirrors were vacuum packaged for high-quality factor resonator operation. The device design contained eight separate piezoelectric aluminium nitride elements arranged as differential pairs for each axis, where each actuator was equipped with a sensing element providing a mechanically coupled electrical feedback signal. The piezoelectric elements connected as actuators required only minimal power and were directly compatible with CMOS low-voltage logic, which eases integration to driving digital systems. The sense elements are used to monitor phase, amplitude, and frequency. A digital control system connected to each of these elements provides accurate frequency and phase control of independent orthogonal resonators, permitting control of the X and Y amplitudes and the refresh rate of the Lissajous pattern.

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A large angle, low voltage, small footprint micromirror for eye tracking and near-eye display applications

Cited by 17 publications

References 4 publications

Investigation of Camera-Free Eye-Tracking Glasses Compared to a Video-Based System

Investigation of Camera-Free Eye-Tracking Glasses Compared to a Video-Based System

Ultralow Power On-the-Eye Vergence and Distance Sensing Through Differential Magnetometry

Resonating AlN-thin film MEMS mirror with digital control

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