Resin Molded Surface Structure for Coating-Free Deep Black

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Solution Overview

Problem

Existing methods for imparting high-quality design and luxurious colors to resin surfaces, such as deep black color, through coating are not suitable for mass production due to issues with uniformity, man-hour, productivity, and cost.

Innovation Solution

A resin molded product with a concave-convex structure is created using a mold, where convex parts have specific dimensions and surface roughness to replicate deep black color without coating, achieved by precise laser processing of the mold and injection molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If coating is applied to the appearance surface of molded products to improve texture and design quality, then the surface appearance is improved, but productivity and manufacturing cost deteriorate due to individual processing requirements

Engineering Contradiction:

Improvesurface appearance qualityVSAvoidmass production efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The mold surface is preliminarily processed with laser to create a microlens array structure before resin injection. This preliminary action transfers the desired surface appearance directly to the molded product during molding, eliminating the need for subsequent coating operations and enabling mass production with high surface quality

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical coating process with an optical approach by forming microlens structures on the mold surface using laser processing. The optical properties of the microlens array directly create the desired surface appearance, substituting the need for physical coating materials and processes

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If coating is applied to achieve luxurious appearance and deep black color, then the aesthetic quality is improved, but manufacturing cost and man-hour increase due to individual processing

Engineering Contradiction:

Improveaesthetic qualityVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The mold surface is copied with a microlens array structure that replicates the desired luxurious appearance and deep black color effect. This master mold can then produce numerous molded products with consistent high aesthetic quality without requiring individual coating operations for each product

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent changes the surface parameter from a flat coated surface to a three-dimensional microlens array structure. This parameter change creates optical effects that produce luxurious appearance and deep black color through light manipulation rather than through coating materials

Inventive Principle:

Principle #35Parameter changes

3Productivity

If a microlens array structure is formed on the mold surface to transfer appearance directly during molding, then productivity and mass production suitability are improved, but manufacturing complexity of the mold increases

Engineering Contradiction:

Improvemass production suitabilityVSAvoidmold structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical mold surface preparation and post-processing mechanisms with a simpler laser processing approach. The laser directly writes the microlens array structure onto the mold surface, reducing mechanical complexity while enabling the sophisticated surface structure needed for high productivity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If laser processing is used to create microlens array on mold surface, then surface roughness and convex part dimensions are precisely controlled, but manufacturing complexity and equipment requirements increase

Engineering Contradiction:

Improveconvex part dimensionsVSAvoidequipment complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces multiple stages of mechanical precision machining and measurement equipment with a single laser processing system. The laser provides both the precision for creating accurate microlens structures and the flexibility for design changes, reducing overall equipment complexity while maintaining high manufacturing precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method allows for the reproduction of deep black color with suppressed glossiness, achieving a luxurious appearance comparable to coated surfaces, while being suitable for mass production.

Implementation Method 1

precise laser processing of the mold

Methodology Applied

Scientific EffectLaser heating: Laser

Data Source

PatentUS20250269566A1Resin molded product, mold, method of manufacturing resin molded product, camera, and printer

Publication Date: 2025.08.28 CANON KK

AI summary

Disclosed are a resin molded product and method for diverse product design to provide a luxurious outer surface with deep black color, with a resin molded product that achieves luxurious colors without coating. The resin molded product includes a plurality of convex parts in a predetermined area with a height of each of the plurality of convex parts between 2 μm and 15 μm, and an arithmetic mean height of high-frequency components in the predetermined area between 12 nm and 20 nm.