Laser Engraving Error Diffusion for Single-Pass Grayscale
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Solution Overview
Problem
Current laser engraving methods require multiple passes to achieve high-quality images, reducing throughput and increasing costs due to the need for additional machines, as they fail to precisely adjust radiation energy for each pixel in a single pass.
Innovation Solution
Measuring the achieved blackening of each pixel during engraving and adjusting the target density of adjacent pixels to compensate for deviations, allowing for accurate gray level reproduction in a single pass by distributing the error to neighboring pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple engraving passes are used to achieve high-quality images with accurate gray levels, then manufacturing precision is improved, but productivity deteriorates due to reduced throughput
Solution Approach 1:
The patent applies preliminary action by performing error diffusion calculations before the actual engraving process. The measuring device detects blackening deviations in real-time during engraving, and the control device pre-calculates corrected radiation energies for subsequent pixels based on these deviations. This allows the system to compensate for engraving errors proactively rather than requiring a separate corrective pass, thereby maintaining high gray level accuracy while improving throughput.
Solution Approach 2:
The patent implements feedback by using a measuring device to detect the actual blackening degree of each pixel during the engraving process. The detected values are fed back to the control device, which compares them with target values and adjusts the radiation energy for subsequent pixels accordingly. This closed-loop feedback mechanism enables real-time error compensation within a single engraving pass, resolving the contradiction between precision and productivity.
2Manufacturing precision
If multiple engraving passes are used to correct blackening deviations, then manufacturing precision is improved, but loss of time increases due to additional engraving runs
Solution Approach 1:
The patent applies continuity of useful action by making the error compensation process continuous and integrated into the single engraving pass. The measuring device continuously monitors blackening deviations as engraving progresses, and the control device continuously adjusts radiation energy for subsequent pixels without interrupting the engraving process. This eliminates the need for separate corrective passes, thereby reducing time loss while maintaining high blackening accuracy.
3Manufacturing precision
If radiation energy is precisely adjusted for each pixel to achieve 64, 128, or 256 gray levels, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by enabling the system to automatically detect and correct its own engraving errors without external intervention. The measuring device self-monitors the blackening degree, and the control device self-adjusts the radiation energy based on detected deviations. This self-correcting mechanism simplifies the overall control architecture compared to systems requiring multiple passes or complex external calibration, while still achieving high gray level precision.
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
Enables high-quality image engraving in a single pass, improving throughput and reducing the need for multiple machines, while maintaining the original gray tone impression and preserving image contrast.
Implementation Method 1
irradiation of the radiation-sensitive layer creates an optical and/or haptic change in the layer referred to below as blackening
Implementation Method 2
the radiation energy or amount of radiation striking each pixel being adjusted so that one of the desired shades of gray corresponding blackening of the pixel is achieved
Data Source
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AI summary
The invention relates to a method for engraving images into a radiation-sensitive layer by means of radiation, in particular for laser engraving. The layer is irradiated point by point such that a blackening (Sist(Pi,k)) is achieved for an image point (Pi,k), said blackening corresponding to a grayscale specified for said image point (Pi,k). In order to allow high-quality images to be engraved in a single engraving pass, the achieved blackening (Sist(Pi,k)) is ascertained for the image point (Pi,k); the difference (DeltaSi,k) between the ascertained blackening (Sist(Pi,k)) and a specified blackening (Ssoll(Pi,k)) is calculated; and the difference (DeltaSi,k) is divided between at least two adjacent image points (Rhoi,k+n; Pi+n,k+m) which are yet to be irradiated.