Optical Sensor Electrode Light Shielding Design

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Solution Overview

Problem

Conventional optical sensors with photo-diodes on semiconductor substrates face reduced detection accuracy due to light incident on non-intended areas, leading to electric charge production and compromised performance.

Innovation Solution

An optical sensor design featuring a semiconductor substrate with an insulation film, a light receiving part including a light receiving element and a reset element, and electrodes with light shielding properties that define the light receiving surface, allowing controlled voltage application to restrict light incidence on non-intended areas and simplify component design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If intervals are secured between photo-diodes and light propagation area to detect light direction, then light direction detection is enabled, but light may incident upon non-intended areas reducing detection accuracy

Engineering Contradiction:

Improvelight direction detection capabilityVSAvoidlight detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The light shielding layer is merged with the electrode structure, where the electrode itself serves as the light shielding component. This integration eliminates the need for separate light shielding structures and intervals, preventing light from incidenting on non-intended areas while maintaining detection functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The electrode is designed to perform multiple functions: it applies control voltage to the reset element and simultaneously acts as a light shielding layer to define the light receiving area. This multi-functionality resolves the contradiction by eliminating the need for separate light shielding structures that would require intervals.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If distance is secured between light shielding layer and photo-diode to specify incidence angle, then light incidence control is achieved, but detection accuracy is reduced due to light on non-intended areas

Engineering Contradiction:

Improvelight incidence controlVSAvoiddetection accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The light shielding function is merged into the electrode structure that is already positioned over the photo-diode. The electrode serves as both the control voltage application component and the light shielding layer, eliminating the need for additional distance intervals while maintaining precise light incidence control.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The insulation film serves as an intermediary layer between the electrode (which acts as light shielding) and the photo-diode. This allows the electrode to be positioned close to the photo-diode for precise light control while maintaining electrical isolation and proper voltage application to the reset element.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If separate light shielding component is used to define light receiving surface, then light receiving area specification is achieved, but component complexity increases

Engineering Contradiction:

Improvelight receiving area definitionVSAvoidcomponent count

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The light shielding function is merged into the electrode structure. The electrode, which is already necessary for applying control voltage to the reset element, is designed with light shielding properties and positioned to define the light receiving area, eliminating the need for separate light shielding components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The electrode is designed as a multi-functional component that simultaneously: (1) applies control voltage to the reset element, (2) acts as a light shielding layer to define the light receiving surface, and (3) provides electrical connection. This reduces component complexity while maintaining manufacturing precision for light receiving area definition.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 design enhances light detection accuracy by preventing unintended light incidence and reduces component complexity, maintaining high performance while simplifying the manufacturing process.

Implementation Method 1

a light receiving element which changes light into electric charge

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

The first electrode has a light shielding property, and a shape of a light receiving surface of the light receiving element is defined by the first electrode

Methodology Applied

Scientific EffectLight shielding: Absorption (EM radiation)

Data Source

PatentUS9224883B2Optical sensor

Publication Date: 2015.12.29 DENSO CORP

AI summary

An optical sensor has a semiconductor substrate, an insulation film formed on the semiconductor substrate, a light receiving part formed on the semiconductor substrate, and an electrode formed on the semiconductor substrate through the insulation film. The light receiving part has a light receiving element which changes light into electric charge, and a reset element which discharges the electric charge accumulated in the light receiving element. The electrode has a first electrode applying a control voltage to the reset element. The first electrode has a light shielding property. The first electrode defines a shape of a light receiving surface of the light receiving element.