Directional Light Sensor IC with Overhanging Shading Structure

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Solution Overview

Problem

Existing directional light sensors in integrated circuits require complex arrangements of tapered stacks to achieve directional sensitivity, which complicates their design and manufacturing.

Innovation Solution

Incorporating a light blocking structure with a first portion extending from the substrate and a second portion overhanging at least one photodetector, which shades the photodetectors from certain angles, allowing for directional sensitivity through differential output signal processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If tapered stacks of opaque slats are used to make the light sensor directionally sensitive, then directional sensitivity is achieved, but the design complexity increases

Engineering Contradiction:

Improvedirectional sensitivityVSAvoiddesign complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the light-blocking function from the complex tapered stack structure and implements it through a simpler overhanging structure that blocks light from reaching specific photodetectors based on incident angle, thereby achieving directional sensitivity with reduced design complexity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a vertical overhanging dimension to the light-blocking structure, creating shadows that fall on specific photodetectors depending on the angle of incident light. This dimensional approach simplifies the design compared to complex tapered stacks while maintaining directional sensitivity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If a light blocking structure with overhanging portion is used, then manufacturing complexity is reduced, but directional sensitivity must be maintained

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddirectional sensitivity

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies local quality by positioning the overhanging light-blocking structure to selectively shade specific photodetectors (e.g., third and fourth photodetectors) while leaving others (first and second photodetectors) exposed to light from certain directions, thereby maintaining directional sensitivity through localized light blocking

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The asymmetric overhanging structure creates different light-blocking patterns for different incident angles, allowing the sensor to distinguish between light coming from above versus the sides, thus maintaining directional sensitivity with a manufacturing-simple structure

Inventive Principle:

Principle #4Asymmetry

3Adaptability or versatility

If photodetectors are arranged with adjacent positioning, then sensor functionality is diversified, but light exposure control becomes more challenging

Engineering Contradiction:

Improvesensor functionalityVSAvoidlight exposure control

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the photodetector array into distinct groups (first/second photodetectors and third/fourth photodetectors) with the overhanging light-blocking structure positioned between them, allowing independent control of light exposure for different sensor functions while maintaining adjacent positioning for compactness

Inventive Principle:

Principle #1Segmentation

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 approach simplifies the design and manufacturing of directional light sensors by providing effective direction-dependent shading, improving resolution and sensitivity without requiring additional processing steps or masks, while protecting non-volatile memory from light exposure.

Implementation Method 1

a light blocking structure comprising a first portion extending from said major surface in between the first photodetector and the second photodetector; and a second portion extending from the first portion and at least partially overhanging at least one of the first photodetector and the second photodetector

Methodology Applied

Scientific EffectLight blocking / Shading: Absorption (EM radiation)

Implementation Method 2

a plurality of photodetectors on a region of said major surface, said plurality of photodetectors comprising a set of first photodetectors for detecting light from a first direction and a set of second photodetectors for detecting light from a second direction

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS9331219B2Integrated circuit with directional light sensor, device including such an IC and method of manufacturing such an IC

Publication Date: 2016.05.03 NXP BV

AI summary

Disclosed is an integrated circuit comprising a substrate having a major surface; a directional light sensor, the directional light sensor comprising a plurality of photodetectors on a region of said major surface, said plurality of photodetectors comprising a set of first photodetectors for detecting light from a first direction and a set of second photodetectors for detecting light from a second direction, wherein a first photodetector is located adjacent to a second photodetector; and a light blocking structure comprising a first portion extending from said major surface in between the first photodetector and the second photodetector; and a second portion extending from the first portion and at least partially overhanging at least one of the first photodetector and the second photodetector. A device including such an IC and a method of manufacturing such an IC are also disclosed.