Multicolor Reversible Recording Erasure via Wavelength Segmentation

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Solution Overview

Problem

Existing reversible recording media face challenges in achieving high display quality due to incomplete erasure of information, especially when dealing with multicolor displays involving multiple stacked recording layers, which leads to issues like degradation of display quality and incomplete erasure defects.

Innovation Solution

A drawing and erasing apparatus that utilizes a light source section with multiple laser elements of different emission wavelengths, a multiplexer to combine these laser beams, and a controller to manage scanning speeds for overlapping scanning on the recording medium, allowing for precise temperature adjustments during erasure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single wavelength laser is used for erasure, then the device structure is simple, but the temperature control precision is insufficient leading to erasure defects

Engineering Contradiction:
Improveerasure qualityVSAvoidlight source structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The light source is segmented into multiple laser elements emitting at different wavelengths, with each wavelength targeting specific recording layers. This segmentation enables precise temperature control for erasing different color layers (cyan, magenta, yellow) independently, resolving the contradiction between erasure quality and device simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different wavelengths are applied to different regions/layers of the recording medium based on their specific absorption characteristics. The cyan layer absorbs 405nm light, magenta absorbs 532nm, and yellow absorbs 650nm, allowing localized and selective erasure of each layer with optimal temperature control.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If overlapping scanning is performed with multiple wavelengths, then temperature level is finely adjusted reducing erasure defects, but the control system complexity increases

Engineering Contradiction:
Improvetemperature control precisionVSAvoidcontrol system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The overlapping scanning technique applies multiple wavelengths continuously to the same region, maintaining continuous heating action that prevents temperature fluctuations. This continuous multi-wavelength irradiation ensures stable temperature control during erasure, improving precision while the control system manages the coordinated operation of multiple lasers.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The scanning system performs periodic overlapping passes over the recording region, with each pass delivering controlled doses of multiple wavelengths. This periodic scanning pattern allows precise temporal control of energy delivery, enabling fine temperature adjustment and preventing overheating or incomplete erasure.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If multiple laser elements are used for multicolor display, then display quality is improved, but the erasure completeness becomes problematic

Engineering Contradiction:
Improvedisplay qualityVSAvoiderasure completeness
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system changes the wavelength parameter of the laser to match the absorption characteristics of different color layers. By selecting specific wavelengths (405nm for cyan, 532nm for magenta, 650nm for yellow), the system achieves complete erasure of each layer while maintaining the multicolor display capability, resolving the contradiction between display quality and erasure completeness.

Inventive Principle:
Principle #35Parameter changes

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

This approach reduces erasure defects and enhances display quality by finely adjusting the temperature levels on the recording medium, enabling effective erasure of information while maintaining the integrity of multicolor displays.

Implementation Method 1

a light source section 30 that includes a plurality of laser elements different from each other in emission wavelength

Methodology Applied
Scientific EffectPhotothermal conversion: Laser

Implementation Method 2

each of the plurality of recording layers being reversible and different from each other in developed color hue

Methodology Applied
Scientific EffectSelective light absorption: Absorption (EM radiation)

Implementation Method 3

a multiplexer that multiplexes a plurality of types of laser light beams outputted from the plurality of laser elements

Methodology Applied
Scientific EffectOptical multiplexing:

Implementation Method 4

perform overlapping scanning of a predetermined region on the reversible recording medium... to cause the scanner section to perform overlapping scanning... to finely adjust a temperature level

Methodology Applied
Scientific EffectThermal diffusion: Conduction (thermal)

Data Source

PatentEP3812159B1Drawing and erasing device and erasing method
Publication Date: 2023.07.26 SONY GROUP CORP
  • EP3812159B1 patent drawingFigure 1
  • EP3812159B1 patent drawingFigure 2
  • EP3812159B1 patent drawingFigure 3~4

AI summary

A drawing and erasing apparatus includes a light source section that includes a plurality of laser elements different from each other in emission wavelength, a multiplexer that multiplexes a plurality of types of laser light beams outputted from the plurality of laser elements, a scanner section that performs scanning with multiplexed light outputted from the multiplexer on a reversible recording medium including a plurality of recording layers, the plurality of recording layers being reversible and different from each other in developed color hue, and a controller that controls a main scanning speed and a sub-scanning speed of the scanner section to cause the scanner section to perform overlapping scanning of a predetermined region on the reversible recording medium during erasure of information written on the reversible recording medium.