In this paper we discuss the geometrical and optical characterization of a miniaturized very wide field-of-view (FOV)
motion sensor inspired by the working principle of insect facet eyes. The goal of the sensor is to detect movement in the
environment and to specify where in the surroundings these changes took place. Based on the measurements of the
sensor, certain actions can be taken such as sounding an alarm in security applications or turning on the light in domotic
applications. The advantage of miniaturizing these sensors is that they are low-cost, compact and more esthetical
compared to current motion detectors.
The sensor was designed to have a very large FOV of 125° and an angular resolution of 1° or better. The micro-optics is
built up of two stacked polymer plates consisting each out of a five by five lens array. In between there is a plate of
absorbing material with a five by five array of baffles to create 25 optically isolated channels that each image part of the
total FOV of 125° onto the detector.
To geometrically characterize the lens arrays and verify the designed specifications, we made use of a coordinate
measuring machine. The optical performance of the designed micro-optical system was analyzed by sending white light
beams with different angles of incidence with respect to the sample through the sensor, comparing the position of the
light spots visible on the detector and determining optical quality parameters such as MTF and distortion.
In this paper we discuss the design of a novel miniaturized image sensor based on the working principle of insect
facet eyes. The main goals are to design an imaging system which captures a large field of view (FOV) and to find
a good trade-off between image resolution and sensitivity. To capture a total FOV of 124°, we split up this FOV
into 25 different zones. Each of these angular zones is imaged by an isolated optical channel on our image sensor.
There is an overlap between the zones to cover the full FOV but the different zones are imaged on separated
regions at the image sensor. Every optical channel in the designed component consists of two lenses that are
tilted with respect to each other and the optical axis. Because of this tilt of the lenses, we are able to minimize
field curvature and distortion in the obtained images at the detector, and have an angular resolution below 1°.
The optical system was implemented and optimized in the ray-tracing program ASAP. The parameters (in one
channel) that are optimized to obtain this large FOV with a good image resolution and sensitivity are the radius
of curvature of the two lenses, their conical factor and their tilt in two directions with respect to the optical axis
of the complete system. The lenses are each placed on a pedestal that connects the lens to a planar substrate.
We also add absorbing tubes that connect the two lenses in one channel to eliminate stray-light between different
optical channels. The obtained image quality of the design is analyzed using our simulation model. This is
determined by different parameters as there are: modulation transfer function, distortion, sensitivity, angular
resolution, energy distribution in each channel and channel overlap. The modulation transfer function shows
us that maximum contrast in the image is reached up to 0.3LP/°, distortion is maximal 21% in one of the 25
different channels, the sensitivity is 0.3% and the resolution is better than 1°.
KEYWORDS: Tolerancing, Phase only filters, Monte Carlo methods, Assembly tolerances, 3D modeling, Statistical analysis, Optics manufacturing, Navigation systems, Manufacturing, Silicon
The advent of Plastic Optical Fibre (POF) opened perspectives for numerous applications in the field of datacommunications.
POF is increasingly popular in the automotive industry as a robust, lightweight, electromagnetic
interference free, easy and cheap to install alternative to electrical wiring for high-speed entertainment, navigation
and data acquisition systems in cars. The main challenge for the introduction of datacommunication
systems based on POF is imposed by the working conditions of automotive applications: systems should remain
fully functional in a temperature range from -40 °C to +115 °C . Furthermore, standardisation and mechanical
design considerations put a number of other boundary conditions.
We designed a misalignment-tolerant optical coupling system according to the Media Oriented Systems Transport
standard (MOST) to convey the divergent beam from a Resonant Cavity Light Emitting Diode (RCLED)
into a Step-Index (SI) multimode POF mounted in a detachable ferrule. In this contribution we describe the
methodology to synthesize the dimensions and tolerances on the optical components in the coupling system.
A Monte Carlo optimisation algorithm on the full three-dimensional (3D) description of the complete RCLED
package and detachable POF ferrule was used to allow a realistic modelling of all misalignments that could occur
in the production chain. We select the best suited system according to manufacturing and assembly capabilities
as well as its suitability for automotive applications.
KEYWORDS: Phase only filters, Tolerancing, Temperature metrology, Epoxies, Monte Carlo methods, Compound parabolic concentrators, Polymer optical fibers, 3D modeling, Light, Refractive index
Today a lot of applications (datacommunication, automation, sensing, automotive . . . ) make use of plastic optical
fibers (POF) to carry data over short distances. In this paper we will focus on the case study of a resonant cavity
light emitting diode (RCLED) in combination with a POF. First we compare the optimal coupling efficiency
of different coupling configurations (with ball lens, micro-lens and reflector) using non-sequential ray tracing
software. Because we want to involve all specified external perturbations of the complete system we use
Monte-Carlo based 3D opto-mechanical tolerancing to obtain the ideal optical system and its dimensions and tolerances.
The definition of the best design will be based on a guaranteed minimum coupled power for a system subject to
prescribed dimensional and geometrical deviations. To define the source model, we used extensive measurements.
We import the measurement data of the light source to obtain realistic simulation results. Therefore we performed
a full quantitative characterization of this source. More in particular we measured the total output power, the
optical spectrum and the far-field pattern by using an integrating sphere, a spectrum analyzer and a goniometric
radiometer respectively at different temperatures. We investigated two different situations, one where the RCLED
emits light directly in air and the other where the light of this source first passes through epoxy before being
measured in air like it is the case in a lot of coupling configurations.
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