Optical Sensor Light Absorbing Layer Reduces Noise

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Solution Overview

Problem

Optical sensors face reduced sensing resolution due to increased noise caused by strong light, particularly sunlight, which leads to black shadows or blurred images, attributed to light reflection from components with reflective surfaces and the need for light collimation structures that further increase noise.

Innovation Solution

An optical sensing device is designed with a substrate, a sensing element layer, a light-shielding layer, and a light-absorbing layer to absorb reflected light, improving sensing resolution by reducing noise. The device includes multiple layers and structures such as metal oxide layers, anti-reflection layers, and microlens structures to regulate light acceptance and collimation, ensuring that stray light is minimized and does not interfere with the sensing elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If light collimation structure is equipped to improve sensing resolution, then sensing resolution is improved, but sensing noise increases due to stray light reflection

Engineering Contradiction:

Improvesensing resolutionVSAvoidsensing noise

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful reflected light into a beneficial effect by using a light absorbing layer to capture the stray light that would otherwise cause noise. The light absorbing layer is strategically positioned to absorb reflected light from reflective components below the sensor, thereby reducing sensing noise while maintaining the light collimation structure for resolution improvement

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces a light absorbing layer as an intermediary element between the light collimation structure and the reflective components below. This intermediary layer absorbs the stray light reflected by components such as batteries or conductive elements, preventing the reflected light from entering the sensing element and causing noise, thus mediating between the collimation structure and the reflective components

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If sensor operates under strong light conditions, then sensing capability is maintained, but black shadows or blurred images occur due to increased noise

Engineering Contradiction:

Improvesensing capabilityVSAvoidimage quality

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent converts the harmful effect of strong light causing noise into a beneficial situation by using the light absorbing layer to capture excess reflected light. Under strong light conditions such as sunlight, the light absorbing layer absorbs the intense reflected light that would otherwise cause black shadows or blurred images, thereby maintaining both sensing capability and image quality

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If reflective components are placed below sensor, then device integration is improved, but sensing noise increases due to light reflection

Engineering Contradiction:

Improvedevice integrationVSAvoidsensing noise

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a light absorbing layer as an intermediary between the reflective components (such as batteries or conductive elements) placed below the sensor and the sensing element above. This intermediary layer absorbs the light reflected by the reflective components, preventing it from reaching the sensing element and causing noise, thus allowing device integration without compromising sensing performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful reflected light from integrated reflective components into a beneficial situation by having the light absorbing layer capture it. The reflective components can be integrated below the sensor for device functionality, and the light absorbing layer converts the potentially harmful reflected light into absorbed energy, eliminating noise while maintaining integration

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 proposed solution effectively reduces sensing noise and enhances the resolution of optical sensors by absorbing reflected light, resulting in clearer images and improved performance even under strong light conditions.

Implementation Method 1

a first light absorbing layer disposed on the second surface

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS11781905B2Optical sensing device and electronic apparatus having the same

Publication Date: 2023.10.10 AU OPTRONICS CORP

AI summary

An optical sensing device includes a substrate, a sensing element layer, a light-shielding layer, and a light absorbing layer. The substrate has a first surface and a second surface opposite to each other. The sensing element layer is disposed on the first surface and includes multiple sensing elements. The light-shielding layer is disposed on the sensing element layer and has multiple openings. An orthogonal projection of the opening on the substrate overlaps an orthogonal projection of the sensing element on the substrate. The light absorbing layer is disposed on the second surface. An electronic apparatus including the optical sensing device is also provided.