Antireflection Film Reduces Moire Interference in Compact Light Irradiation Device
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Solution Overview
Problem
The existing light irradiation devices for inspection systems can cause moire interference, leading to image quality issues, especially at certain magnification ratios, and previous solutions to mitigate this problem increase manufacturing costs and compromise the compact design.
Innovation Solution
A light irradiation device with a transparent plate and microscopic reflecting sections, where an antireflection film is applied to the object-facing surface to reduce moire interference by controlling the angle between the reflecting sections and the image-taking device's pixel layout, thereby minimizing reflections that contribute to interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple reflecting members are arranged on the transparent plate to create compact light irradiation, then the system size is reduced and closeup imaging is enabled, but moire interference occurs on the image screen
Solution Approach 1:
The patent applies an antireflection film (a simple, inexpensive coating) on the transparent plate to suppress moire interference. This low-cost solution eliminates the need for complex expensive alternatives while maintaining the compact design with microscopic reflecting members.
Solution Approach 2:
The patent changes the optical parameters of the transparent plate by applying an antireflection film that controls light reflection characteristics. This parameter change (reducing reflection) directly addresses the moire interference problem while preserving the compact structure.
2Object-affected harmful factors
If reflecting members are arranged in uneven pitch or irregular shape to reduce moire interference, then moire interference is reduced, but manufacturing cost increases significantly
Solution Approach 1:
Instead of using expensive irregularly-shaped or unevenly-pitched reflecting members, the patent employs a simple antireflection film coating on regularly arranged microscopic reflecting members. This approach dramatically reduces manufacturing cost while effectively suppressing moire interference.
Solution Approach 2:
The patent extracts the moire interference suppression function from the complex geometry of reflecting members and implements it through a separate antireflection film layer. This separation allows regular, easy-to-manufacture reflecting members to be used while still achieving interference suppression.
3Illumination intensity
If a half mirror is arranged at 45 degrees on the observation axis to irradiate light coaxially, then light can be irradiated from the coaxial direction, but the system becomes bulky and the image-taking device cannot approach the object closely
Solution Approach 1:
The patent transitions from the conventional 45-degree half-mirror arrangement (requiring lateral space) to a thin-plate configuration where light irradiation occurs through the thickness dimension of the plate. This dimensional change enables coaxial illumination while maintaining a compact form factor that allows closeup imaging.
Solution Approach 2:
The patent uses a thin transparent plate structure that can be positioned close to the object without obstructing the image-taking path. The plate's thinness allows the system to achieve compact dimensions while still providing the necessary light irradiation function from the coaxial direction.
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 effectively reduces moire interference while maintaining a compact design and low production costs, allowing for clear, high-quality images to be taken in close-up mode.
Implementation Method 1
an antireflection film that covers the object facing surface
Implementation Method 2
multiple reflecting sections that are laid out on other surface (also be called as an opposite object facing surface) of the light permeable plate with forming a microscopic space therebetween with its light reflecting surface facing a direction of the object
Implementation Method 3
a light source section arranged at a position where at least a part of the emitted light is transmitted inside the light permeable plate, reaches the light reflecting surface
Data Source
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AI summary
The light irradiation device is provided that can reduce moire interference with a simple and low-cost arrangement without sacrificing a compact design by comprising a transparent plate 31 which has a predetermined thickness and one of whose surfaces is arranged as an object facing surface 31a to face an object W such as a product on which light is to be irradiated, multiple reflecting sections 32 that are laid out on other surface of the transparent plate 31 with forming a microscopic space S therebetween with its light reflecting surface facing a direction of the object W, a light source section 5 arranged at a position where at least a part of the emitted light is transmitted, reaches the light reflecting surface, is reflected on the light reflecting surface and is emitted from the object facing surface 31a, and an antireflection film 33 that covers the object facing surface 31a.