Optical Filter Layer Reflective Layer Detection Device

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Solution Overview

Problem

Existing optical sensors with front lights face challenges in achieving good detection accuracy due to light interference and reduced light use efficiency, particularly because part of the light is either directly absorbed by photodiodes or absorbed by light-blocking portions in collimators.

Innovation Solution

A detection device is designed with a plurality of photodiodes, a front light including a light guide plate and a light source, and an optical filter layer with light guide paths and a light-blocking portion. The optical filter layer is accompanied by a reflective layer between the light guide plate and the optical filter layer, which enhances light use efficiency by reflecting scattered light back into the light guide plate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a front light is provided between the object to be detected and photodiodes, then illumination of the object is improved, but light from the front light directly enters the photodiodes and reduces detection accuracy

Engineering Contradiction:

Improveillumination of objectVSAvoiddetection accuracy

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The optical filter layer is divided into multiple light guide paths corresponding to individual photodiodes, with light-blocking portions between them. This segmentation prevents light from one photodiode's path from entering adjacent photodiodes, reducing cross-talk while maintaining illumination.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The optical filter layer acts as an intermediary between the front light and photodiodes. It selectively transmits light along defined paths while blocking direct light entry into photodiodes, thus maintaining illumination benefits while preventing detection interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a light-blocking portion is added to the collimator, then direct light interference with photodiodes is reduced, but light use efficiency decreases due to light absorption

Engineering Contradiction:

Improvedetection accuracyVSAvoidlight use efficiency

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The reflective layer converts the harmful effect of light-blocking (absorbed light being wasted) into a benefit by reflecting the blocked light back into the light guide plate. This allows the light to be reused for illumination, maintaining detection accuracy while improving light use efficiency.

Inventive Principle:

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

Solution Approach 2:

Instead of discarding the light blocked by the light-blocking portion, the reflective layer recovers it by reflecting it back into the light guide plate. This recovered light can then be redirected to illuminate the object, reducing energy waste.

Inventive Principle:

Principle #34Discarding and recovering

3Use of energy by moving object

If light is emitted directly toward the object from the front light, then illumination is efficient, but scattered light enters the photodiodes and reduces detection accuracy

Engineering Contradiction:

Improvelight emission efficiencyVSAvoiddetection accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The optical filter layer extracts and removes scattered light that would otherwise enter the photodiodes. By taking out the harmful scattered light component while allowing useful illumination light to pass through the light guide paths, it maintains illumination efficiency while improving detection accuracy.

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 detection device improves detection accuracy by reducing direct light interference with photodiodes and enhances light use efficiency by reflecting scattered light, thereby improving the overall performance of the optical sensor.

Implementation Method 1

a reflective layer that is provided between the light guide plate and the optical filter layer and overlaps the light-blocking portion of the optical filter layer

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

The optical filter layer includes a plurality of light guide paths that at least partially overlap the photodiodes

Methodology Applied

Scientific EffectLight guiding: Waveguide (optics)

Implementation Method 3

a light-blocking portion having higher absorptance of the light than the light guide paths

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS12264963B2Detection device

Publication Date: 2025.04.01 MAGNOLIA WHITE CORP

AI summary

According to an aspect, a detection device includes: a plurality of photodiodes arranged on a substrate; a front light including a light guide plate disposed so as to overlap the photodiodes and a light source configured to emit light to a side surface of the light guide plate; and an optical filter layer provided between the photodiodes and the light guide plate of the front light. The optical filter layer includes a plurality of light guide paths that at least partially overlap the photodiodes, and a light-blocking portion having higher absorptance of the light than the light guide paths. The detection device includes a reflective layer that is provided between the light guide plate and the optical filter layer and overlaps the light-blocking portion of the optical filter layer.