Optical Sheet Forming Device with Non-Uniform T-Die Gap
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional extrusion techniques for forming thin optical sheets with complex contours, such as light guide panels for mobile devices, struggle to accurately create stereoscopic projections while maintaining standard thickness, often resulting in sinkage and inaccurate shaping due to insufficient resin volume distribution.
Innovation Solution
An optical sheet forming technique utilizing an extruding unit with a T-die having a standard gap and an enlarged gap portion, combined with a forming roll unit and a thick portion forming mechanism, allows for the precise formation of thicker sections within the sheet, ensuring accurate contour creation and maintaining standard thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional extrusion technique with standard gap T-die is used to form thin optical sheets, then standard thickness is maintained, but stereoscopic projections (thicker portions) cannot be accurately formed due to insufficient resin volume
Solution Approach 1:
The T-die gap is made non-uniform with a standard gap portion and an enlarged gap portion. The enlarged gap portion corresponds to the position where thicker sections are needed in the final product. This local variation in gap size allows increased resin volume to be supplied to specific areas, enabling accurate formation of stereoscopic projections while maintaining standard thickness in other areas.
Solution Approach 2:
The resin volume distribution is adjusted in advance during the extrusion process by designing the T-die gap configuration. The enlarged gap portion pre-supplies additional resin to the regions that will become thicker sections, ensuring sufficient material is available before the forming rolls shape the sheet. This preliminary action prevents sinkage and ensures accurate contour formation.
2Manufacturing precision
If recessed groove pattern is provided only on forming rolls to create projections, then standard thickness is maintained, but sinkage occurs due to insufficient resin supply to recesses
Solution Approach 1:
The T-die gap is locally enlarged at specific positions corresponding to where thicker sections are needed. This creates a non-uniform resin flow distribution, supplying additional resin volume to specific regions before the material contacts the forming rolls. This local quality adjustment prevents sinkage in recessed areas while maintaining standard thickness elsewhere.
Solution Approach 2:
The additional resin volume is supplied in advance through the enlarged gap portion of the T-die, before the molten resin contacts the forming rolls. This preliminary action ensures that sufficient resin is available to fill recessed grooves and form accurate projections, preventing sinkage defects that would otherwise occur with uniform gap extrusion.
3Productivity
If uniform resin flow is ejected from T-die, then standard thickness sheet is formed, but complex contour shapes with varying thickness cannot be achieved
Solution Approach 1:
The T-die gap is designed with different sizes at different positions: a standard gap portion for areas requiring standard thickness and an enlarged gap portion for areas requiring thicker sections. This local differentiation enables the extrusion of sheets with complex varying thickness contours while maintaining continuous forming efficiency, as the entire process remains a single-pass extrusion operation.
Solution Approach 2:
The T-die gap is segmented into distinct portions: a standard gap portion and an enlarged gap portion. This segmentation allows different resin flow rates and thicknesses to be achieved in different regions of the extruded sheet simultaneously, enabling complex contour shapes while maintaining continuous production efficiency.
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 enables the accurate extrusion of optical sheets with preset shapes, enhancing light guiding efficiency by ensuring all light from the light source is effectively directed and diffused, preventing sinkage and maintaining optical properties.
Implementation Method 1
sheet-shaped molten resin is ejected from an extruder through a T-die
Implementation Method 2
a forming roll unit configured to solidify and carry the ejected sheet-shaped molten resin in the extrusion direction
Data Source
AI summary
An extruding unit, a forming roll unit and a thick portion forming mechanism are provided. The extruding unit has an ejecting slit which ejects sheet-shaped molten resin. The ejecting slit includes a standard gap portion and an enlarged gap portion. The standard gap portion is formed as a gap having a constant size. The enlarged gap portion is formed as a gap larger than the standard gap portion in a position corresponding to a thick portion. The thick portion forming mechanism forms one or several thick portions which are thicker than other portion, in the sheet-shaped molten resin continuously in the extrusion direction.