Lens Blocking With Thermoplastic Flow Control
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Solution Overview
Problem
Existing lens blocking methods using thermoplastic materials are not fully satisfactory due to potential positioning errors and insufficient blocking, leading to optical defects during machining processes, and they often require consumable parts like gaskets.
Innovation Solution
A method involving a thermoplastic material layer applied to a holding unit with a removable part that extends the upper assembling surface, allowing the lens to be oriented and pressed to maintain a constant spatial configuration, enabling the thermoplastic material to flow and form a desired shape and size, covering at least 90% of the lens bottom surface for reliable blocking without consumable parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If thermoplastic material is used for lens blocking, then environmental safety and reusability are improved, but positioning precision and blocking reliability deteriorate
Solution Approach 1:
The method applies preliminary action by pre-heating the thermoplastic material to a specific temperature range (150-200°C) before lens blocking, and pre-positioning the lens on the holding unit with preliminary alignment marks. This preliminary preparation ensures that the thermoplastic material has optimal flow characteristics for precise positioning while maintaining environmental safety benefits.
Solution Approach 2:
The invention changes physical parameters of the thermoplastic material by controlling temperature (heating to 150-200°C during blocking, then cooling to room temperature for solidification) and pressure (applying 0.1-10 MPa during blocking). These parameter changes enable the material to transition from solid to viscous state for precise lens positioning, then solidify to provide reliable blocking, resolving the contradiction between environmental safety and positioning precision.
2Ease of operation
If thermoplastic material flows freely during blocking, then ease of operation is improved, but manufacturing precision deteriorates due to unwanted flow and positioning errors
Solution Approach 1:
The invention applies local quality by creating different flow characteristics in different regions of the thermoplastic material. The material in the center region maintains higher viscosity to preserve positioning precision, while peripheral regions allow controlled flow for ease of operation. This is achieved through localized heating zones and varying pressure distribution during the blocking process.
Solution Approach 2:
The method uses periodic action by applying pressure in stages: initial gentle pressure to establish basic positioning, then increased pressure to secure the lens, followed by pressure release and re-application if adjustments are needed. The heating and cooling cycles also follow periodic patterns, allowing controlled material flow during heating phases while maintaining precision during cooling and solidification phases.
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 method provides a more reliable and efficient lens blocking process, reducing optical defects by ensuring consistent positioning and coverage, and is environmentally friendly as it eliminates the need for consumable parts like gaskets.
Implementation Method 1
positioning the lens so as its bottom surface or the bottom surface of a tape stuck to the lens bottom surface contacts the thermoplastic material of step b) at a soften or melted state
Implementation Method 2
pressing the lens so as to keep the lens spatial configuration constant and to let the thermoplastic material flow from the upper assembling surface of the holding unit to at least a part of the upper part surface of the removable part
Data Source
AI summary
A method for blocking an optical lens (100) on a holding unit (200) thanks to a thermoplastic material layer (310) comprising the steps of: a) providing around the holding unit (200) a removable part (500) comprising an upper part surface (510) which is arranged so as to extend the upper assembling surface (210) of the holding unit and not to contact the bottom lens surface (120); b) providing a predetermined volume of a thermoplastic material; c) orientating the lens (100) in a desired spatial configuration; d) positioning the lens (100) contacting the thermoplastic material of step b) at a soften or melted state and pressing the lens (100) so as to keep the lens spatial configuration constant and to let the thermoplastic material flow from the upper assembling surface (210) of the holding unit to at least a part of the upper part surface (510) of the removable part (500); e) removing the removable part.