Compact Optical System Using Diffractive Surface
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Solution Overview
Problem
Existing optical systems for imaging apparatuses in industrial and medical fields require a large number of optical elements to increase the angle of view, leading to a bulky system due to the need for parallel light beams to be focused, which is inefficient and increases system size.
Innovation Solution
An optical system comprising a front group and a rear group with a light-shielding member, where the front group forms an intermediate image of the object in a non-parallel light section, and the rear group uses a diffractive surface to split and focus light beams at different wavelengths, allowing for a smaller and more compact design with increased angle of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cylindrical mirrors and diffraction grating are used to split light beams, then wavelength separation is achieved, but the system size increases and angle of view is limited
Solution Approach 1:
The patent changes the fundamental parameter of light beam configuration from parallel to non-parallel (converging/diverging). By making the light beam non-parallel in the first section and utilizing the diffractive surface to create an intermediate image, the system achieves wavelength separation without requiring the bulky parallel beam configuration, thus reducing system size while maintaining separation precision
Solution Approach 2:
The patent introduces a second section perpendicular to the first section, creating a three-dimensional optical path configuration. The diffractive surface operates in the second section to split light beams that converged in the first section, utilizing spatial dimensionality to achieve wavelength separation in a compact arrangement rather than requiring extended linear configuration
2Adaptability or versatility
If lenses are disposed nearer to increase angle of view, then more optical elements are needed, but system complexity and size increase
Solution Approach 1:
The diffractive surface performs multiple functions simultaneously: it acts as a wavelength separator (diffraction grating function), a focusing element (lens function in the second section), and enables intermediate image formation. This multi-functionality eliminates the need for separate lenses and optical elements that would otherwise be required to achieve the same angle of view and spectral separation
Solution Approach 2:
The patent extracts the focusing function from the diffraction grating by introducing a separate diffractive surface that operates on non-parallel light beams. This allows the system to achieve both wide angle of view and wavelength separation without requiring multiple lenses, as the diffractive surface handles both spectral and spatial control in a single element
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 enables a compact optical system with enhanced angle of view and improved imaging performance by utilizing non-parallel light beams and diffractive surfaces, reducing the number of optical elements and system size while maintaining precise image formation across various wavelengths.
Implementation Method 1
The rear group has a diffractive surface that splits a light beam that passes through the opening into light beams at different wavelengths in the second section and focuses the light beams on different locations in the second section
Data Source
AI summary
Optical system includes a front group, light-shielding member, and rear group that are arranged in this order in direction from object side toward image side. The light-shielding member is provided with opening elongated in first direction. The front group does not image the object at the opening in first section parallel to the first direction and forms intermediate image of the object at the opening in second section perpendicular to the first direction. The rear group has diffractive surface that splits light beam that passes through the opening into light beams at different wavelengths in the second section and focuses the light beams on different locations in the second section. Light beam that is emitted from the front group 11 and that enters the opening is non-parallel light in the first section.