Light-Blocking Recess Structure for Touchpad Panel Border Coating

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Solution Overview

Problem

Conventional illuminated push-button switch cover members with light-blocking layers on the front surface suffer from degradation and light leakage, especially at borders where coatings do not flow well, compromising design integrity.

Innovation Solution

A panel with a light-transmissive main body and side portions featuring recesses at borders, where a light-blocking part is formed on the inner surface to prevent thinning and enhance light-blocking efficiency, minimizing light leakage and maintaining design quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the light-blocking layer is formed on the front surface of the key top, then the light-blocking function is achieved, but the light-blocking layer degrades with use and light leakage occurs

Engineering Contradiction:

Improvelight-blocking function durabilityVSAvoidlight leakage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

Instead of forming the light-blocking layer on the front surface (conventional approach), the patent inverts the approach by forming the light-blocking layer on the inner surface of the key top. This inversion allows the light-blocking function to be maintained while preventing degradation and light leakage issues associated with front-surface coating.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent addresses the coating flow problem at borders by introducing a recess structure at the border between the upper portion and side portions. This dimensional change creates a stepped structure that ensures proper coating flow and thickness distribution, preventing light leakage at critical border areas.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the light-blocking layer is formed on the inner surface through coating, then degradation is avoided, but the coating material does not flow well at borders resulting in thin light-blocking layer and light leakage

Engineering Contradiction:

Improvelight-blocking layer durabilityVSAvoidcoating thickness uniformity at borders

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The recess structure is formed in advance before coating application. This preliminary action creates a geometric feature that guides the coating material flow, ensuring that the coating material properly fills the recess and achieves uniform thickness at borders, preventing thin spots that would cause light leakage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The recess is specifically located at the border area where coating flow problems occur. This local structural modification针对性地 addresses the coating thickness issue at borders without affecting other areas, ensuring proper coating distribution and preventing light leakage at critical locations.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10133371B2Panel and touchpad

Publication Date: 2018.11.20 KK TOKAI RIKA DENKI SEISAKUSHO

AI summary

A panel includes a light-transmissive main body including an upper portion and a plurality of side portions contiguous with the upper portion, a recess being formed at a border between an inner surface of the upper portion and an inner surface of at least one of the plurality of side portions, and a light-blocking part formed in the recess and on an inner surface of the main body except a design part that transmits light, the light-blocking part being configured to block light.