Cylindrical Light Guide for Omnidirectional Proximity Sensor

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Solution Overview

Problem

Proximity sensors with a single light emitting device struggle to provide omnidirectional visibility of the indication state due to light blocking effects from the circuit board, leading to increased manufacturing costs and power consumption when attempting to enhance light emission.

Innovation Solution

Incorporating a cylindrical light guide that surrounds the circuit board with a light-transmitting material, featuring a first and second light outgoing region, and using reflective and refractive surfaces to guide light emissions omnidirectionally, allowing the light to be observed from any angle without the need for additional light emitting devices on the rear surface of the circuit board.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single light emitting device is mounted on the circuit board, then the manufacturing cost is reduced, but the outgoing light cannot reach the side facing the other main surface of the circuit board due to light blocking effect

Engineering Contradiction:
Improvemanufacturing costVSAvoidoutgoing light visibility
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

A light guide member is introduced as an intermediary component between the light emitting device and the external environment. The light guide member receives light from the light emitting device mounted on one main surface of the circuit board and transmits it to multiple directions including the side facing the other main surface, thereby enabling omnidirectional visibility without requiring additional light emitting devices on the other main surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If the amount of current supplied to the light emitting device is increased, then the amount of outgoing light is increased, but the power consumption is increased

Engineering Contradiction:
Improveoutgoing light amountVSAvoidpower consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

Instead of increasing light output in one dimension by supplying more current, the light guide member distributes light in multiple spatial dimensions (omnidirectional transmission). This allows the same light output to be visible from all directions, effectively increasing illumination coverage without increasing the current supply or power consumption.

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

3Illumination intensity

If a light emitting device is mounted on both main surfaces of the circuit board, then omnidirectional light emission is achieved, but the number of components and manufacturing processes are increased

Engineering Contradiction:
Improveomnidirectional light emissionVSAvoidnumber of components
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The light guide member serves multiple functions: it transmits light from the light emitting device, distributes light in multiple directions, and enables visibility from all sides of the proximity sensor. This single multi-functional component replaces what would otherwise require multiple light emitting devices mounted on different surfaces, thereby reducing overall device complexity.

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 configuration enables efficient omnidirectional light emission from a single light emitting device, reducing manufacturing costs and maintaining good visibility of the indication state while minimizing power consumption.

Implementation Method 1

a cylindrical light guide guiding outgoing light from the light emitting device to be emitted to outside... featuring a first and second light outgoing region, and using reflective and refractive surfaces to guide light emissions omnidirectionally

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

using reflective and refractive surfaces to guide light emissions omnidirectionally

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2355355B1Proximity sensor
Publication Date: 2016.08.17 OMRON CORP
  • EP2355355B1 patent drawingFigure 1
  • EP2355355B1 patent drawingFigure 2
  • EP2355355B1 patent drawingFigure 3

AI summary

A proximity sensor includes a circuit board (30) provided with a processing circuit, a light emitting device (32) mounted on the surface (30a) of the circuit board (30), and a light-transmitting cylindrical light guide (43) surrounding the portion of the circuit board (30) having the light emitting device (32) mounted thereon and guiding the outgoing light from the light emitting device (32) to be emitted to outside. The cylindrical light guide (43) includes the first light emitting surface as the first light outgoing region causing the light emitted from the light emitting device (32) to pass therethrough and directly emitting the light to outside, a reflective surface (43a1) reflecting the light emitted from the light emitting device (32) to guide the light through the cylindrical light guide (43) in the circumferential direction, and the second light emitting surface (43a2) as the second light outgoing region emitting, to outside, the light reflected on the reflective surface (43a1) and propagated through the cylindrical light guide (43).