Transparent Electrode Photoreceiver for Compact Light Sensing
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Solution Overview
Problem
Conventional photocell devices, especially those integrated with ASICs, face challenges in size reduction and require expensive filters to compensate for infrared radiation, limiting their ability to efficiently adjust display brightness in response to ambient light.
Innovation Solution
An integrated circuit device with a photoreceiver and a transparent electrode on a semiconductor substrate, where the electrode's charge is varied to alter the spectral response of the photoreceiver, allowing for precise adjustment of spectral sensitivity and composition analysis of incident light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If photoreceiver is integrated with ASIC, then device size is reduced, but photoreceiver remains proportionally large due to signal amplification requirements
Solution Approach 1:
The device is segmented into distinct functional layers: the photoreceiver layer for light detection and the ASIC layer for signal processing. This segmentation allows each component to be optimized independently, with the photoreceiver being made as small as possible while the ASIC handles the signal amplification functions, thereby reducing the overall device volume while maintaining photoreceiver miniaturization.
Solution Approach 2:
The patent transitions from a planar integration approach to a three-dimensional stacked architecture where the photoreceiver and ASIC are positioned at different vertical levels. This dimensional change allows the photoreceiver to be miniaturized without being constrained by the ASIC's signal amplification requirements, as the coupling is achieved through vertical interconnects rather than lateral integration.
2Volume of moving object
If conventional integrated approaches are used, then device size is reduced, but expensive filters are required to compensate for infrared radiation properties of silicon
Solution Approach 1:
An intermediary optical filter layer is introduced between the ambient environment and the photoreceiver to selectively block infrared radiation before it reaches the silicon photoreceiver. This mediator approach eliminates the need for expensive post-processing filters while maintaining the benefits of silicon's infrared sensitivity, thereby reducing manufacturing costs without sacrificing device miniaturization.
Solution Approach 2:
The patent converts silicon's harmful property (infrared sensitivity that causes noise) into a benefit by using the same silicon material's optical properties to advantage. By carefully designing the photoreceiver structure and using wavelength-selective optics, the system leverages silicon's natural spectral response to enhance visible light detection while inherently suppressing infrared interference, eliminating the need for additional filtering components.
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
Enables compact, cost-effective adjustment of display brightness by mimicking human eye spectral response, reducing energy consumption and improving user experience through precise light sensing and filtering.
Implementation Method 1
an electrode arranged proximate the photoreceiver and configured to receive a charge to alter a spectral response of the photoreceiver to incident light that passes through the electrode to the photoreceiver
Implementation Method 2
a photoreceiver formed on the semiconductor substrate... to sense ambient light
Data Source
AI summary
Embodiments relate to photoreceivers, such as photodiodes. In one embodiment, an integrated circuit device comprises a photodiode, and an electrode arranged over or on top of the photodiode. The electrode is substantially transparent or otherwise exhibits a lower absorption rate, such that light or other radiation can pass through the electrode to the photodiode. Varying a charge applied to the electrode enables the spectral sensitivity of the underlying photodiode to be altered, tuned or otherwise adjusted.