Pressure-Sensitive Adhesive Sheet for Display Device Concealment

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Light-blocking pressure-sensitive adhesive (PSA) sheets used for concealing metal members in electronic devices face challenges in maintaining consistent appearance when applied to processed surfaces, as differences in color between the PSA sheet and the adherend can emphasize contrasts, impairing uniform concealment.

Innovation Solution

A PSA sheet with a light transmittance of 20% or lower and a lightness (L*) value between 20 and 70 in the L*a*b* color space, combined with a black colorant and metal oxide, is used to minimize color contrast and ensure consistent concealment, even on processed surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a light-blocking PSA sheet is used to conceal metal members, then the metal member is concealed, but color contrast between the PSA sheet and processed adherend surface emphasizes the contrast, impairing consistent appearance

Engineering Contradiction:

Improveconcealment consistencyVSAvoidcolor contrast

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the L* value (lightness) of the PSA layer within the range of 20 to 70 in the L*a*b* color space. This parameter adjustment ensures that the PSA sheet's color matches the processed metal surface, reducing color contrast and improving concealment consistency. The light transmittance is simultaneously controlled at 20% or lower to maintain adequate light blocking while achieving uniform appearance.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the PSA layer has low light transmittance for good concealment, then the adherend is well concealed, but the L* value must be carefully controlled to match processed surfaces

Engineering Contradiction:

Improveconcealment effectivenessVSAvoidcolor matching precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent establishes specific parameter ranges: light transmittance of 20% or lower for concealment effectiveness, and L* value between 20 and 70 for color matching. These parameter changes provide both good concealment and reduced color contrast simultaneously.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining a PSA layer with specific optical properties (low light transmittance, controlled L* value) with a release liner. This composite structure enables the PSA sheet to achieve both effective concealment and color matching to processed surfaces.

Inventive Principle:

Principle #40Composite materials

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 PSA sheet effectively conceals processed metal surfaces with reduced inconsistency, maintaining adhesive strength and optical properties, suitable for applications in portable electronic devices.

Implementation Method 1

The PSA layer has a light transmittance of 20% or lower

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS20230323161A1Pressure-sensitive adhesive sheet, display device and laminate

Publication Date: 2023.10.12 NITTO DENKO CORP

AI summary

To provide a PSA sheet capable of providing good concealment to an adherend whose surface to which the PSA sheet is applied has been processed. Provided is a PSA sheet having a PSA layer. The PSA layer has a light transmittance of 20% or lower and an L* value of 20 or higher and 70 or lower, defined in the L*a*b* color space.