Ophthalmic Lens Edging Reference Point Alignment
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Solution Overview
Problem
Existing methods for edging ophthalmic lenses result in a slight offset between the cut-out lens outline and the presentation lens outline, affecting centering and mounting in spectacle frames, requiring reworking to adjust the lens shape.
Innovation Solution
A method involving a first support on the presentation lens to define a reference point, followed by a second support on the ophthalmic lens to maintain the same orientation, ensuring the edging machine cuts the lens along a contour identical to the presentation lens, using image sensors and calculating means to align the pupillary point with the centering point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the blocking support is glued at the center of the boxing rectangle perpendicular to the lens front face, then the blocking operation is simple and straightforward, but an offset occurs between the cut-out lens outline and the presentation lens outline
Solution Approach 1:
The patent applies preliminary action by determining the exact blocking position on the presentation lens before edging the ophthalmic lens. The method involves acquiring an image of the presentation lens, determining its outline shape, and calculating the precise blocking position based on the centered outline. This pre-determined blocking position is then transferred to the ophthalmic lens, ensuring that the blocking support is positioned accurately to prevent outline offset during edging.
2Ease of operation
If the presentation lens is placed on a flat surface in front of a camera, then the outline acquisition is straightforward, but the tilt of the presentation lens relative to the camera differs from the tilt of the ophthalmic lens during edging
Solution Approach 1:
The patent uses copying by acquiring an image of the presentation lens and using this digital copy to determine the outline shape and calculate the blocking position. The centered outline from the image is virtually transferred to the ophthalmic lens, creating a digital template that guides the edging process. This copying approach allows the outline information to be accurately transferred without physically moving the presentation lens, thereby maintaining outline accuracy despite different lens tilts.
3Ease of operation
If the blocking support extends along a longitudinal axis perpendicular to the lens front face, then the edging machine can easily engage the lens, but the offset between outlines affects the centering of the lens in front of the patient's pupil
Solution Approach 1:
The patent applies feedback by using the acquired image of the presentation lens to determine the outline shape and calculate the precise blocking position. This information feeds back into the edging process, allowing the system to adjust the blocking position on the ophthalmic lens to compensate for potential outline offsets. The feedback loop ensures that the blocking position is optimized to maintain both easy machine engagement and accurate lens centering.
Data Source
AI summary
A method for preparing an ophthalmic lens to be edged based on a presentation lens, includes: fixing a first support a face of the presentation lens, the first support's shape defining a first reference point; positioning the presentation lens by the first support in an optical machine having an image sensor; acquiring, with the image sensor, an image of the presentation lens; determining, on the acquired image, the outline of the presentation lens; positioning a pupillary point relative to the outline; positioning the outline of the presentation lens relative to the ophthalmic lens so the pupillary point is superimposed on a centering point of the ophthalmic lens; and fixing a second support a face of the ophthalmic lens, the second support having a shape defining a second reference point, the second support fixed on the ophthalmic lens so its second reference point is superimposed on the first reference point.