Spectacle Lens Hole Angle Calculation for Pantoscopic Adjustment

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Solution Overview

Problem

Conventional spectacle lens processing devices face difficulties in accurately forming holes that account for the pantoscopic angle, leading to challenges in aligning the line of sight and optical axis, which affects user vision.

Innovation Solution

A spectacle lens processing device with a control unit that acquires the pantoscopic angle and determines the relative angle between the drilling tool and the lens, allowing for precise hole formation by adjusting the drilling tool's position based on the acquired pantoscopic angle and lens holding shaft angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the hole angle is determined based only on the lens shape (surface angle), then the processing is simple, but the pantoscopic angle cannot be adjusted and the line of sight and optical axis cannot be properly aligned

Engineering Contradiction:
Improvehole angle setting simplicityVSAvoidalignment of line of sight and optical axis
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The system changes the parameter basis for hole angle determination from solely lens surface geometry to a composite calculation incorporating both lens surface angle and pantoscopic angle. The control unit computes the hole angle by combining these two parameters, enabling both operational simplicity and proper alignment of line of sight with optical axis.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the hole angle is set freely by the operator, then the pantoscopic angle can be taken into account, but the setting procedure becomes complex and difficult to operate

Engineering Contradiction:
Improvehole angle accuracy for pantoscopic adjustmentVSAvoidsetting procedure complexity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The system performs self-service by automatically calculating the appropriate hole angle based on input parameters (lens shape and desired pantoscopic angle). The control unit executes the computation without requiring the operator to manually determine complex angular relationships, thereby maintaining precision while simplifying operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control unit acts as an intermediary between the operator's requirements and the processing parameters. It receives input about desired pantoscopic adjustment and lens geometry, then computes and outputs the precise hole angle, mediating the complex relationship between these parameters without exposing the operator to the complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the lens is held by the lens holding shaft at a position other than the optic center, then the angle of the held lens changes, but it becomes difficult to form the hole at the target angle

Engineering Contradiction:
Improvelens holding position flexibilityVSAvoidhole angle accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system incorporates feedback by measuring the actual angle of the held lens using a lens shape measurement unit, then using this measured angle as input to the control unit's calculation. The control unit computes the hole angle based on the actual held lens angle and desired pantoscopic angle, compensating for any deviation from optic center holding and maintaining hole angle accuracy.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3480639B1Eyeglass lens processing devices and processing control data-creation programs
Publication Date: 2021.12.08 NIDEK CO LTD
  • EP3480639B1 patent drawingFigure 1
  • EP3480639B1 patent drawingFigure 2
  • EP3480639B1 patent drawingFigure 3

AI summary

A spectacle lens processing device includes a control unit that controls processing. The control unit acquires a position of a hole formed in a lens and a pantoscopic angle. The pantoscopic angle is an angle in a vertical plane between a visual axis of a user and an optical axis of the lens when the user wears spectacles in which the lens after processing is mounted and faces forward. The control unit determines, based on the acquired pantoscopic angle, a relative angle between a drilling tool and the lens when the hole is formed in the lens in the acquired position of the hole.