Wedge-Shaped Optical Element for Grazing Incidence Illumination
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Solution Overview
Problem
Machine-readable symbol readers face challenges in reading symbols formed in surface relief or displayed electronically due to difficulties in creating suitable lighting conditions, particularly with high incidence angle illumination, which can cause operator fatigue and eye strain.
Innovation Solution
The use of wedge-shaped optical elements that provide grazing incidence illumination, allowing for controlled and uniform light distribution, reducing the need for precise angle control and minimizing direct illumination exposure to the operator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high incidence angle illumination is used to read surface relief symbols, then reading capability is improved, but operator fatigue and eye strain increase
Solution Approach 1:
A wedge-shaped optical element is introduced as an intermediary between the illumination source and the operator. This optical element redirects the high incidence angle illumination away from the operator's eyes while maintaining the illumination's effectiveness for reading surface relief symbols, thus resolving the contradiction between reading capability and operator comfort
Solution Approach 2:
The optical element is designed with specific geometric properties (wedge shape with particular angles) to selectively redirect illumination in specific directions. The local geometry of the optical element creates different light paths: one path illuminates the symbol effectively while the other path directs light away from the operator, addressing the contradiction locally
2Reliability
If flood illumination is used to illuminate the entire symbol, then reading capability is improved, but direct illumination exposure to the operator increases
Solution Approach 1:
The wedge-shaped optical element serves as a mediator that takes flood illumination and transforms it into a controlled beam that does not directly expose the operator. The optical element's geometry ensures that while the symbol receives adequate illumination, the operator is protected from direct light exposure
3Measurement precision
If grazing incidence illumination is provided, then reading accuracy is improved, but device complexity increases
Solution Approach 1:
The invention changes the geometric parameters of a simple wedge-shaped optical element to achieve grazing incidence illumination. By carefully selecting the wedge angle and positioning, the system achieves improved reading accuracy without requiring complex mechanical adjustment mechanisms, thus minimizing the increase in device complexity
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
Improves the reading of machine-readable symbols on mixed media by providing consistent and ergonomic illumination, enhancing reading accuracy and reducing operator discomfort.
Implementation Method 1
the first and second major faces which propagate a diminishing amount of light passing through the optical element along the length thereof from the base toward the end by total internal reflection
Implementation Method 2
which exit the light passing through the optical element from the base by refraction through at least one of the first or second major faces
Data Source
AI summary
A machine-readable symbol reader can include a housing, a window, an illumination source, a wedge-shaped optical element, and a sensor array. Illumination can be coupled into the optical element through a base surface of the optical element and out of the optical element through a leg surface of the optical element. Illumination beams coupled out of the optical element through the leg surface can be parallel or substantially parallel to one another, and can exit the machine-readable symbol reader at a grazing angle to illuminate a machine-readable symbol at a grazing angle.