Opto-Electronic Modules With Embedded Light-Blocking Regions
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Solution Overview
Problem
Miniaturized optical sensors face challenges in managing internal optical interference and stray light, particularly when mounted behind transparent or semi-transparent covers, which can lead to signal-to-noise ratio issues and reduced precision.
Innovation Solution
The development of opto-electronic modules with a substrate-mounted light emitting and sensing elements, separated by a non-transparent separation member and covered with a transparent glass having embedded light-blocking regions, which helps reduce optical cross-talk and stray light interference, improving signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor is mounted behind a transparent or semi-transparent cover to enable optical signal transmission, then the sensor can detect light signals, but optical interference and stray light from the cover increase the noise level
Solution Approach 1:
A light blocking element is introduced as an intermediary component between the transparent cover and the sensing element. This mediator selectively blocks harmful optical interference and stray light while allowing the desired optical signals to reach the sensor, thus resolving the contradiction between maintaining signal detection capability and reducing optical noise
Solution Approach 2:
The light blocking element is positioned specifically at locations where optical interference occurs, such as around the sensing element or at strategic points within the optical path. This localized approach blocks harmful light only where needed while preserving the transparent cover's overall light transmission function
2Volume of moving object
If the sensor size is reduced to meet miniaturization requirements, then the device becomes more compact, but optical crosstalk between subcomponents increases
Solution Approach 1:
Light blocking elements are strategically placed between adjacent sensing elements or optical components within the miniaturized sensor. These intermediaries prevent optical crosstalk by blocking stray light from one component from reaching adjacent components, enabling compact design without sacrificing measurement accuracy
Solution Approach 2:
Instead of increasing lateral separation between components (which would increase device size), the light blocking elements extend in the vertical dimension or utilize the depth of the optical path to prevent crosstalk. This allows miniaturization in the planar dimensions while maintaining optical isolation through three-dimensional light blocking structures
3Illumination intensity
If the intensity of reflected light from the cover is similar to the signal of interest, then the cover allows adequate light transmission, but the signal-to-noise ratio deteriorates
Solution Approach 1:
The light blocking element acts as a mediator that discriminates between desired optical signals and unwanted reflected light from the cover. By selectively blocking stray light paths while allowing direct optical signals to pass through, it improves the signal-to-noise ratio without compromising the cover's light transmission function
Solution Approach 2:
The harmful reflected light from the cover is extracted or removed from the optical path using light blocking elements positioned to intercept these specific stray light paths. This separates the desired signal from the noise, allowing the cover to maintain its light transmission function while eliminating the interference
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These modules effectively minimize optical interference and enhance signal quality, enabling precise measurements in various applications, including medical and health-related uses, by maintaining well-defined light paths and protecting sensing elements from unwanted light.
Implementation Method 1
The cover includes embedded light-blocking regions to help reduce optical cross-talk
Data Source
AI summary
Opto-electronic modules, which can be fabricated in a wafer-scale process, include light emitting and/or light sensing devices mounted on or in a substrate. The modules, which can include various features to help reduce the occurrence of optical cross-talk and help prevent interference from stray light, can be used in a wide range of applications, including medical and health-related applications. For example, performing a measurement on a human body can include bringing a portion of the human body into direct contact with an exterior surface of the opto-electronic module and using a differential optical absorption spectroscopy technique to obtain an indication of a physical condition of the human body.