Pointing Device Light Leakage Prevention via Extraction

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Solution Overview

Problem

Existing meter apparatuses suffer from light leakage causing halation due to gaps between components, limiting design flexibility and requiring large caps to prevent light leakage, which affects visual recognition and reduces the quality of the meter.

Innovation Solution

A pointing device with a light blocking member that covers the entire outer peripheral surface of the pointing shaft and includes a flange portion to cover the bottom surface of the proximal end portion, preventing light from leaking and allowing for a miniaturized cap or no cap at all, while maintaining effective light guidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a cap is used to prevent light leakage from the pointer, then halation is reduced, but the cap size must be large to cover gaps effectively, increasing device complexity and limiting design flexibility

Engineering Contradiction:
ImprovehalationVSAvoidcap size
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the light-blocking function from the cap and relocates it to the pointing shaft itself. The pointing shaft is designed with a light-blocking layer on its outer peripheral surface, which prevents light leakage directly at the source without requiring a large cap structure. This separation of functions allows the cap to be minimized or eliminated while maintaining effective light control.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a cap to block light from leaking outward, the invention inverts the approach by making the pointing shaft itself light-blocking. The light-blocking layer is applied to the outer peripheral surface of the pointing shaft, reversing the conventional wisdom that the cap should be the primary light-blocking component. This inversion eliminates the need for a large cap while effectively preventing halation.

Inventive Principle:
Principle #13The other way round (Inversion)

2Object-affected harmful factors

If the pointing shaft diameter is increased to prevent light leakage, then halation is reduced, but the pointer cannot be miniaturized, affecting device compactness

Engineering Contradiction:
ImprovehalationVSAvoidpointing shaft diameter
Core Design Contradiction:
Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The patent applies local quality by adding a light-blocking layer specifically to the outer peripheral surface of the pointing shaft where light leakage occurs. This localized treatment prevents halation without requiring the entire pointing shaft to have increased diameter. The light-blocking layer provides the necessary light control properties only at the critical interface between the pointing shaft and surrounding structures.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If a light blocking member is added to cover the pointing shaft, then light leakage is prevented, but device complexity increases

Engineering Contradiction:
Improvelight leakageVSAvoidnumber of components
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the light-blocking function with the pointing shaft by applying a light-blocking layer directly to its outer peripheral surface. This integration eliminates the need for a separate light-blocking member, as the pointing shaft itself becomes the light-blocking component. The merging of functions reduces the number of parts while maintaining effective light control.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pointing shaft is given multiple functions: it serves as both the mechanical indicator component and the light-blocking element. By applying the light-blocking layer to the pointing shaft, it simultaneously performs its primary function of indicating values and its secondary function of preventing light leakage. This multi-functionality reduces overall device complexity by eliminating dedicated light-blocking components.

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

The solution effectively prevents halation by covering the pointing shaft's outer surface and bottom surface, allowing for a more flexible pointer design and reducing the need for a large cap, thereby enhancing the meter's visual clarity and design freedom.

Implementation Method 1

a rotary shaft (8) made of a transparent material having light guiding properties and rotating and moving on the display plate (D)

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a light blocking member (10A) which includes a cylindrical main body (10) having both end portions adapted to insert the pointing shaft (92) and the rotary shaft (8) respectively thereinto by press-fitting

Methodology Applied
Scientific EffectLight blocking: Absorption (EM radiation)

Data Source

PatentEP2702366B1Pointing device and meter apparatus provided with the same
Publication Date: 2020.04.01 YAZAKI CORP
  • EP2702366B1 patent drawingFigure 1
  • EP2702366B1 patent drawingFigure 2A~2B
  • EP2702366B1 patent drawingFigure 3

AI summary

A pointing device includes a pointer having light guiding properties, a cap that is attached to the pointer and has light blocking properties, a pointing shaft that is vertically formed on a proximal end portion of the pointer, and a light blocking member. The light blocking member includes a cylindrical main body having both end portions for inserting the pointing shaft and a rotary shaft of a motor having light guiding properties respectively thereinto to prevent illuminating light propagating through the rotary shaft from a light source and entering the pointing shaft from leaking from an outer peripheral surface of the pointing shaft.