Planar Light Irradiation Mask Layout for Uniform Illuminance
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Solution Overview
Problem
Existing sample observation apparatuses using planar light irradiation experience non-uniform radiation illuminance distribution due to interference fringes caused by diffraction at the edges of aperture masks, particularly with coherent light sources like lasers.
Innovation Solution
The aperture mask is designed with opening edges that have linear spreads or asymmetrical shapes relative to the focusing line, suppressing interference fringes and ensuring a uniform radiation illuminance distribution by preventing overlapping diffraction patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If an aperture mask is disposed on the optical path to limit the irradiation range of planar light, then the irradiation range is controlled and adjacent observation areas are not irradiated, but interference fringes due to diffraction at the aperture mask edges are generated, causing non-uniform radiation illuminance distribution
Solution Approach 1:
The aperture mask is designed with asymmetrical opening shapes (such as rectangular, triangular, or trapezoidal openings) rather than symmetrical circular openings. This asymmetry causes the diffraction patterns from different edges to have different characteristics, preventing them from overlapping and reinforcing each other, thereby suppressing interference fringes and achieving uniform illuminance distribution across the irradiation range
Solution Approach 2:
Different edges of the aperture mask opening are designed with different geometrical characteristics (e.g., different lengths, orientations, or shapes). This local differentiation ensures that diffraction patterns from each edge are distinct and do not coincide, eliminating the reinforcement of interference fringes and producing uniform light intensity distribution in the irradiated area
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 allows for the output of planar light with a uniform radiation illuminance distribution, enhancing the accuracy of sample observation by reducing interference fringes and ensuring consistent illuminance across the irradiated area.
Implementation Method 1
planar light used in the sample observation apparatus described above is formed by focusing light emitted from a light source using a light focusing element such as a cylindrical lens
Implementation Method 2
interference fringes due to diffraction on the edge of the aperture mask are generated
Implementation Method 3
interference fringes due to diffraction in the opening edges are generated, and there is concern that a radiation illuminance distribution of the planar light may become non-uniform
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
A light irradiation device (2) includes: a light source (21) configured to output light (L0) having coherence; a light focusing element (23) having a focusing axis (F1) and a non-focusing axis (F2) intersecting with the focusing axis (F1) and configured to focus the light (L0) on a focusing line (K) so as to generate planar light (LI); and an aperture mask (22) having an opening part (24) that limits a part of luminous fluxes of the light (L0) transmitted from the light source (21) to the light focusing element (23). The opening part (24) of the aperture mask (22) has opening edges (25A) disposed to extend in a direction along the focusing axis (F1) of the light focusing element (23), and, in a case in which the opening edges (25A) are projected onto the focusing line (K), corresponding projected portions (P) have linear spreads.