Lens Array Element Inclined End Face Mold Release
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Solution Overview
Problem
The existing lens array elements face challenges in maintaining accurate alignment and releasing from metal molds due to level differences between perpendicular reference surfaces and inclined draft surfaces, leading to deformation and reduced alignment accuracy, which affects light utilization efficiency and illuminance uniformity in projection-type image display devices.
Innovation Solution
A lens array element with a rectangular plate-like shape featuring inclined end faces and trapezoidal reference surfaces that provide a draft, allowing for accurate positioning and improved releasing properties without damaging the reference surface, enabling precise alignment with the optical axis and reducing deformations during molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a perpendicular reference surface is formed on the end face of the lens array element for accurate alignment, then alignment precision is improved, but the element cannot be released from the metal mold due to lack of draft
Solution Approach 1:
The end face of the lens array element is segmented into two distinct regions: a reference surface region with a perpendicular surface for alignment precision, and a draft region with an inclined surface for mold releasing. This segmentation allows each region to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the end face are given different surface properties: the reference surface region has a perpendicular surface (0° inclination) for accurate alignment, while the draft region has an inclined surface (e.g., 5-15° inclination) for easy mold releasing. This local differentiation of surface quality resolves the contradiction between alignment precision and manufacturability.
2Measurement precision
If the end face is used as a reference surface for alignment, then positioning accuracy is improved, but the accuracy of the end face shape becomes significantly important, increasing manufacturing difficulty
Solution Approach 1:
The end face is divided into a reference surface region and a draft region. The reference surface region is specifically designed and manufactured to high precision with a perpendicular surface, while the draft region can have lower precision requirements since its primary function is mold releasing rather than alignment.
Solution Approach 2:
High manufacturing precision is applied locally to the reference surface region where accuracy is critical for alignment, while the draft region can be manufactured with standard precision. This localized approach to quality control reduces overall manufacturing difficulty while maintaining positioning accuracy.
3Measurement precision
If a perpendicular reference surface is formed on the end face, then alignment accuracy is improved, but level differences occur between the reference surface and inclined draft surface, causing deformation during mold releasing
Solution Approach 1:
The draft region with the inclined surface is prepared in advance during the molding process. This preliminary draft angle ensures that when the element is released from the mold, the release force is distributed smoothly from the draft region toward the reference surface region, preventing sudden stress concentration and deformation at the interface.
Solution Approach 2:
The inclined draft surface acts as a cushioning zone that absorbs and distributes the mechanical stress during mold releasing. By providing this gradual transition zone beforehand, the perpendicular reference surface is protected from direct stress that would cause deformation, maintaining its integrity and alignment accuracy.
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
The solution ensures accurate positioning of the lens array element with respect to the optical axis, enhancing light utilization efficiency and preventing illuminance unevenness, while maintaining the integrity of the reference surface for precise alignment in projection-type image display devices.
Implementation Method 1
Each of end faces of the rectangular plate-like external shape forms an inclined surface that slants inward from one of plate surfaces toward another of the plate surfaces
Implementation Method 2
a reference surface perpendicular to the plate surface is formed on a part of at least two adjoining end faces among the end faces
Implementation Method 3
Light beams divided by the individual lenses of the first lens array 38 are focused on the image display element 36, while being superimposed, by a corresponding number of divided lenses constituting the second lens array 39
Data Source
AI summary
A lens array element has a rectangular plate-like external shape, and includes plate surfaces that functions as light transmission surfaces; and a plurality of cellular lenses that are formed on at least one of the plate surfaces. Each of end faces 4 of the rectangular plate-like external shape forms an inclined surface that slants inward from a plate surface 6 on one side toward a plate surface 2 on the other side, and a reference surface 5 perpendicular to the plate surface is formed on a part of at least two adjoining end faces among the end faces. A front view shape of the reference surface region arranged side-by-side with the inclined surface of the end face is a trapezoid, an oblique side 7 of the trapezoid is disposed so as to extend from a plate surface on one side toward the plate surface 2 on the other side, and an upper side 9 of the trapezoid is disposed on a side of the other of the plate surfaces. Regarding the reference surface provided to the rectangular plate-like end face for optical alignment, the occurrence of inaccuracy due to the releasing properties at the time of molding the lends array element using a metal mold is suppressed.