Integrated Rain and Solar Sensing Module with Multi-Lens Optical Path

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Solution Overview

Problem

Conventional rain sensors are inefficient due to limited light collimation and reflection, and solar radiation sensors provide inaccurate measurements with only one or two detection zones, leading to inappropriate control of automotive systems.

Innovation Solution

An integrated rain and solar radiation sensing module with multiple light emitting elements, input lenses, output lenses, and light receiving elements, configured to collimate, focus, and detect light efficiently on a transparent substrate, allowing for improved rainfall and solar radiation measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional rain sensors use a single input lens per light emitting element, then the device complexity is reduced, but the light collection efficiency and measurement precision deteriorate

Engineering Contradiction:
Improvelight collection efficiencyVSAvoidnumber of lenses
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the light detection function into multiple segments by using multiple input lenses (at least two) per light emitting element. Each lens captures light from different angular ranges, and all lenses focus their collimated light onto a single light detecting element. This segmentation increases light collection efficiency without requiring multiple detecting elements, thus improving productivity while controlling device complexity.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If solar radiation sensors use only one or two detection zones, then the device complexity is reduced, but the measurement precision of solar radiation deteriorates

Engineering Contradiction:
Improvesolar radiation measurement accuracyVSAvoidnumber of detection zones
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the light detecting elements serve multiple functions: they detect both reflected light from the windshield (for rain sensing) and transmitted solar radiation (for solar radiation sensing). By using the same detecting elements for both purposes with different optical path configurations, the system achieves multi-zone solar radiation detection capability without proportionally increasing device complexity, thus improving measurement precision while managing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of energy

If conventional rain sensors use limited light paths, then the device complexity is reduced, but the light energy utilization deteriorates

Engineering Contradiction:
Improvelight energy utilization efficiencyVSAvoidoptical path configuration
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent adds an angular dimension to light collection by using multiple input lenses positioned at different locations and orientations. Each lens captures light reflected at different angles from the windshield surface, effectively utilizing light energy that would otherwise be missed by a single-lens configuration. This dimensional expansion improves energy utilization while the shared light detecting element keeps the overall structure relatively simple.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 module enhances efficiency in rainfall detection and accuracy in solar radiation measurement, enabling better control of automotive systems, such as wipers and HVAC, with cost savings from shared light detection elements.

Implementation Method 1

A typical automobile rain sensor includes light emitting elements (e.g., light emitting diodes)

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Implementation Method 2

input lenses adapted to collimate light emitted by the light emitting elements

Methodology Applied
Scientific EffectCollimation: Lens

Implementation Method 3

receive an amount of the collimated light that is reflected off of the windshield

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

output lenses adapted to receive an amount of the collimated light that is reflected off of the windshield and to focus the light

Methodology Applied
Scientific EffectFocusing: Lens

Implementation Method 5

light detecting elements (e.g., a photodiodes) that are adapted to receive the focused light from the output lens and to convert the received light into electrical output signals

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP3535564B1Integrated rain and solar radiation sensing module
Publication Date: 2022.07.13 LITTELFUSE INC
  • EP3535564B1 patent drawingFigure 1
  • EP3535564B1 patent drawingFigure 2
  • EP3535564B1 patent drawingFigure 3

AI summary

An integrated rain and solar radiation sensing module including at least two light emitting elements, a plurality of input lenses, wherein at least two of the plurality of input lenses are configured to receive and collimate light emitted by each of the light emitting elements, a plurality of output lenses numbering at least twice as many as the plurality of input lenses, wherein each output lens is configured to receive and focus light that is collimated by at least one of the plurality of input lenses and reflected off of a transparent substrate, and a plurality of light receiving elements, wherein each light receiving element configured to receive focused light from at least one of the output lenses and to convert the received light into an electrical output signal proportional to the received light.