Light Guide Lens Surface Roughness and Cover Layer Molding
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Solution Overview
Problem
The existing methods for forming a non-concave-convex surface on light guide lenses in display apparatuses are inefficient, requiring multiple polishing steps with sandpaper and a buff, which increases the number of manufacturing steps and reduces productivity.
Innovation Solution
A display apparatus with a light guide member featuring a concave-convex curved surface with surface roughness of 40-250 μm, covered by a cover layer such as an adhesive film or coating layer, which forms a non-concave-convex surface on the image display side, allowing light to be output without the need for additional polishing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light guide lens with a concave-convex surface is used, then light can be guided effectively, but light scattering at the exit surface causes image blurring and darkening
Solution Approach 1:
The patent divides the light guide lens into two distinct surfaces: a concave-convex input surface for effective light guidance and a flat output surface for clear light emission. This segmentation allows each surface to optimize its function independently, resolving the contradiction between light guidance efficiency and output quality.
Solution Approach 2:
The patent applies different surface qualities to different regions of the light guide lens. The input surface has a concave-convex structure optimized for light capture and guidance, while the output surface is maintained flat and smooth for clear light emission. This local differentiation resolves the contradiction by giving each region the quality it needs for its specific function.
2Manufacturing precision
If the light guide lens surface is polished using traditional methods with sandpaper and buff, then a non-concave-convex surface is achieved, but the number of manufacturing steps increases significantly
Solution Approach 1:
The patent incorporates surface smoothing directly into the molding process, performing the smoothing action beforehand rather than requiring separate post-processing steps. The mold design includes a flat surface that directly forms the output surface of the light guide lens, eliminating the need for subsequent polishing operations with sandpaper and buff.
Solution Approach 2:
The patent replaces the mechanical polishing system (sandpaper and buff) with a molding-based surface formation approach. By using a precision mold with a flat surface, the desired smooth output surface is created directly during manufacturing, substituting complex mechanical post-processing with a more efficient forming process.
3Manufacturing precision
If multiple sandpaper grits are used in sequence for polishing, then surface roughness is reduced, but the number of processing steps increases from about #80 to about #2000 grit
Solution Approach 1:
The patent performs surface smoothing during the initial molding process rather than requiring multiple sequential polishing steps. The mold is designed with a flat surface that directly forms the smooth output surface of the light guide lens, eliminating the need for progressive polishing through multiple grit stages.
Solution Approach 2:
The patent changes the approach from gradual surface modification through multiple polishing stages to a single-step surface formation process. By controlling the molding parameters and using a precision flat mold surface, the desired surface quality is achieved directly without requiring progressive refinement through multiple grit levels.
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 configuration simplifies the manufacturing process by reducing the need for extensive polishing, enhances productivity, and improves visibility by reducing light scattering and image blurring, resulting in a seamless image display across multiple units.
Implementation Method 1
Light output through a concave-convex surface of the light guide lens is scattered at such an exit surface of the light guide lens, resulting in image blurring and darkening
Data Source
AI summary
A method for manufacturing a display apparatus includes a first step of arranging a display panel (110) inside a housing (130); a second step including a light guide lens formation step of forming a curved surface (151b) of a light guide lens (151) into a concave-convex surface having surface roughness of 40-250 μm, and a cover layer formation step of forming a light guide member (150) in such a manner that the curved surface (151b) of the light guide lens (151) is covered by a cover layer (152) to form an image-display-side surface of the cover layer (152) into a non-concave-convex surface; and a third step of bonding the light guide member (150) to a surface of an outer peripheral edge part of the display panel (110) and a surface of the window frame (130).