Detector Array Substrate Alignment for LIDAR Resolution

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Solution Overview

Problem

Photodetector arrays are constrained by substrate and package size limitations, limiting their ability to maintain consistent detector pitch across multiple substrates, which affects the resolution and efficiency of light detection systems like LIDAR.

Innovation Solution

A system comprising multiple substrates arranged in an edge-to-edge array with detector elements and signal receiver circuits, where each substrate includes a ball grid array or land grid array for electrical coupling, and encapsulation with microlenses to maintain consistent detector pitch and reduce parasitic coupling, allowing for high-resolution light detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple substrates are used to expand detector array size, then the detector array can overcome substrate size limitations, but maintaining consistent detector pitch across substrates becomes difficult

Engineering Contradiction:

Improvedetector array sizeVSAvoiddetector pitch consistency

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The detector array is divided into multiple substrates arranged in an edge-to-edge configuration. Each substrate contains a portion of the detector elements, allowing the overall array to exceed the size limitations of a single substrate while maintaining a continuous detector pattern across substrate boundaries.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An encapsulation layer with integrated alignment structures serves as an intermediary between multiple substrates. This encapsulation layer provides mechanical support and includes alignment features that ensure precise positioning of substrates relative to each other, maintaining consistent detector pitch across substrate boundaries.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If substrates are arranged edge-to-edge to form a borderless array, then optical crosstalk between substrates is reduced, but alignment precision requirements increase

Engineering Contradiction:

Improveoptical crosstalkVSAvoidsubstrate alignment precision

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The encapsulation layer acts as an intermediary that provides alignment structures to facilitate precise substrate positioning. These alignment structures enable accurate edge-to-edge alignment, reducing optical crosstalk while managing the precision requirements through mechanical guidance features.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The edge-to-edge arrangement of substrates creates a borderless detector array where all detector elements exist at the same optical potential level. This eliminates optical discontinuities and crosstalk that would occur with traditional bordered arrangements, as there are no physical or optical barriers between substrates.

Inventive Principle:

Principle #12Equipotentiality

3Measurement precision

If detector elements are densely packed to improve resolution, then light detection efficiency increases, but parasitic coupling between adjacent detectors increases

Engineering Contradiction:

Improvelight detection resolutionVSAvoidparasitic coupling

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

Parasitic coupling effects are extracted and isolated through the encapsulation layer design. The encapsulation material and alignment structures are positioned to minimize electromagnetic interference between adjacent detector elements, allowing dense packing while reducing harmful parasitic effects.

Inventive Principle:

Principle #2Taking out (Extraction)

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

The solution enables a 'borderless' carrier substrate that maintains consistent detector pitch across substrates, enhancing the resolution and efficiency of light detection systems by reducing optical crosstalk and parasitic coupling, particularly in LIDAR applications.

Implementation Method 1

Each detector element of the plurality of detector elements generates a respective detector signal in response to light received by the detector element

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

encapsulation with microlenses to maintain consistent detector pitch and reduce parasitic coupling

Methodology Applied

Scientific EffectLens focusing: Lens

Data Source

PatentUS11393865B1Optical receiver systems and devices with detector array comprising a plurality of substrates aligned with an encapsulation layer comprising an alignment structure

Publication Date: 2022.07.19 WAYMO LLC

AI summary

The present disclosure relates to optical receiver systems. An example system includes a plurality of substrates disposed in an edge-to-edge array along a primary axis. Each respective substrate of the plurality of substrates includes a plurality of detector elements. Each detector element of the plurality of detector elements generates a respective detector signal in response to light received by the detector element. The plurality of detector elements is arranged with a detector pitch between adjacent detector elements of the plurality of detector elements. Each respective substrate of the plurality of substrates also includes a signal receiver circuit configured to receive the detector signals generated by the plurality of detector elements. The respective substrates of the plurality of substrates are disposed such that the detector pitch is maintained between adjacent detector elements on their respective substrates.