Motor Light Guide for Homogeneous Pointer Illumination

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Solution Overview

Problem

Mounting miniature stepper motors on the rear side of a printed circuit board (PCB) in automotive instrumentation poses challenges for illumination, as it lacks mechanical and electrical support for light sources, resulting in inhomogeneous pointer illumination.

Innovation Solution

A motor design with a light guide that allows the light source to be installed on the PCB, enabling it to be powered and positioned for consistent illumination, with the option to mount LEDs on either the front or rear side, and using guide pegs for secure attachment, ensuring homogeneous illumination across the pointer's range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the motor is mounted on the rear side of the PCB, then space restrictions are satisfied and new cluster technologies are accommodated, but mechanical support and electrical power for the LED are lost, resulting in inhomogeneous pointer illumination

Engineering Contradiction:

Improvemounting flexibilityVSAvoidillumination homogeneity

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent introduces a light guide as an intermediary component between the LED and the pointer shaft. This light guide transfers light from the LED (mounted on the PCB) through the motor housing to illuminate the pointer shaft uniformly, solving the illumination problem caused by rear mounting while maintaining mounting flexibility

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the spatial arrangement by mounting the LED on the PCB plane rather than requiring it to be integrated with the motor shaft. The light guide extends the illumination path from the PCB plane through the motor structure to the pointer, enabling rear mounting while maintaining illumination quality

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If a transparent shaft is used with a centred LED, then constant illumination over the entire range of rotation is achieved, but the motor must be mounted on the front side of the PCB, limiting design flexibility

Engineering Contradiction:

Improveillumination constancyVSAvoidmounting position flexibility

Core Design Contradiction:

Illumination intensityVSAdaptability or versatility

Solution Approach 1:

Instead of mounting the motor on the front side of the PCB with the LED integrated into the motor, the invention inverts the arrangement by mounting the motor on the rear side of the PCB and using a light guide to deliver light from the PCB-mounted LED through the motor housing to the pointer shaft

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The light guide acts as a mediator that transfers illumination from the PCB-mounted LED to the pointer shaft, enabling the motor to be mounted on the rear side while maintaining constant illumination throughout the pointer's rotation range

Inventive Principle:

Principle #24Intermediary (Mediator)

3Illumination intensity

If three LEDs are used to illuminate the pointer, then adequate illumination over the 300 degree turning radius is achieved, but component cost and complexity increase

Engineering Contradiction:

Improvepointer illumination adequacyVSAvoidnumber of LEDs

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The invention extracts the illumination function from multiple LEDs and consolidates it into a single LED mounted on the PCB. The light guide distributes this single light source's output to illuminate the entire pointer shaft uniformly, reducing component count and complexity while maintaining adequate illumination

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The single LED mounted on the PCB serves the universal function of illuminating the entire pointer shaft through the light guide, replacing the need for multiple LEDs positioned at different locations. This multi-functional approach reduces component count while achieving the same illumination effect

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

Enables consistent and cost-effective illumination of pointers by allowing flexible LED placement and power supply, maintaining the benefits of shaftless motors while accommodating rear PCB mounting, ensuring clear driver visibility and reduced component costs.

Implementation Method 1

A light guide is provided in the motor. The light guide is arranged to direct light into the pointer shaft

Methodology Applied

Scientific EffectLight guidance: Waveguide (optics)

Data Source

PatentEP2699875B1Motor for a rotatable and illuminable pointer

Publication Date: 2018.04.04 JUKEN SWISS TECH

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AI summary

The present invention relates to a motor designed for being mounted on a circuit board (303), the circuit board (303) having a pointer side (305) and a rear side (307). The motor can be used for rotating an illuminated pointer. The motor comprises a light conveying pointer shaft (103) for projecting through the circuit board (303) from the rear side (307) of the circuit board (303) to the pointer side (305) of the circuit board (303). The pointer shaft (103) is arranged to convey light to the pointer. The motor further comprises a light guide (113) for conveying light from a light source (301) mounted on the circuit board (303) to a rear end of the pointer shaft (103), the rear end of the pointer shaft (103) being on the rear side (307) of the circuit board (303). Thus, the motor can be advantageously mounted on the rear side of the circuit board (303).