Optical Sensing Structure for Large-Angle Light Crosstalk
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Solution Overview
Problem
Optical sensing devices face significant interference from crosstalk due to large-angle reflected light from non-detected objects, leading to inaccurate distance measurements and the 'full count' phenomenon when objects are extremely close, where light energy becomes infinite.
Innovation Solution
The implementation of alternately stacked light-filtering and light-transmitting layers above the photosensitive region to block large-angle incident light, reducing crosstalk and preventing the 'full count' phenomenon by controlling the ratio of large-angle to small-angle light that reaches the photosensitive region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional light blocking devices are used to reduce crosstalk, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent integrates the light blocking function directly into the existing package structure by forming light blocking regions within the transparent encapsulation layer. This nesting approach eliminates the need for separate external light blocking devices, thereby reducing device complexity while maintaining measurement accuracy through effective crosstalk reduction.
Solution Approach 2:
The transparent encapsulation layer serves multiple functions: it provides structural protection, maintains environmental sealing, and now also incorporates light blocking regions to reduce crosstalk. By making the encapsulation layer multi-functional, the patent avoids adding separate components, thus improving measurement accuracy without increasing device complexity.
2Reliability
If light blocking structures are added to prevent full count phenomenon, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The patent combines the light blocking structures with the transparent encapsulation layer formation process. The light blocking regions are created by depositing opaque materials (such as metal layers) during the same manufacturing sequence used to create the encapsulation structure, thereby improving reliability without significantly increasing manufacturing complexity.
Solution Approach 2:
Instead of making the entire encapsulation layer opaque, the patent applies light blocking properties only to specific regions where crosstalk occurs. This localized approach maintains the overall transparency needed for light transmission while preventing the full count phenomenon, and can be implemented using targeted material deposition techniques that align with existing manufacturing processes.
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
This solution effectively reduces optical crosstalk, enhances measurement accuracy, and prevents the 'full count' phenomenon, ensuring reliable distance sensing even at close object proximity without additional light blocking devices, thereby improving the overall performance of optical sensing devices.
Implementation Method 1
an optical structure located above the photosensitive region... block large-angle incident light from entering the photosensitive region
Implementation Method 2
the light is reflected by an object, and then is received by a photodiode (PD) to convert the light energy into an electrical signal
Data Source
AI summary
An optical sensing device can include: a semiconductor having a photosensitive region; an optical structure located above the photosensitive region; and where the optical structure comprises alternately stacked light-filtering layers and light-transmitting layers, in order to block large-angle incident light from entering the photosensitive region.