Compact Telescope With Movable Aspherical Mirrors
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Solution Overview
Problem
Current space telescopes with single focal lengths lack the ability to provide high optical quality across multiple focal lengths without using expensive deformable mirrors or bulky components, and existing multifocal telescopes do not meet the requirements of compactness and high image quality for large pupil diameters.
Innovation Solution
A telescope design featuring three multifocal aspherical mirrors with retractable components, optimized using Korsch equations and Zernike polynomials to compensate for aberrations, allowing for variable focal lengths while maintaining high image quality and using only classic aspherical components without a deformable mirror.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single focal length telescope design is used, then the optical system is simple and compact, but it cannot provide high optical quality across multiple focal lengths
Solution Approach 1:
The patent introduces movable aspherical components that can be repositioned along the optical axis to change the effective focal length of the telescope. The components include a movable secondary mirror and a movable tertiary mirror that can be positioned at different locations to achieve different focal lengths (e.g., f/24, f/18, f/12), transforming a static single-focal-length system into a dynamic multi-focal-length system without requiring multiple complete optical assemblies
Solution Approach 2:
The patent changes the optical parameters of the system by introducing aspherical components with specific asphericity coefficients (e.g., k = -0.5 to -2.0) that can be moved to different positions. By changing the position parameter of these aspherical components along the optical axis, the system achieves different focal lengths and maintains optimal optical quality across multiple focal settings, rather than being fixed at a single focal length
2Manufacturing precision
If deformable mirrors are used to achieve high image quality across multiple focal lengths, then optical quality is improved, but cost and device complexity increase
Solution Approach 1:
The patent divides the optical correction function into separate fixed aspherical components rather than using a single deformable mirror. The optical system includes a primary mirror, a secondary mirror with aspherical surface, and a tertiary mirror with aspherical surface, where each component has a fixed aspherical shape designed to correct specific aberrations at different focal lengths, eliminating the need for complex real-time deformation control
Solution Approach 2:
The patent replaces expensive deformable mirrors with simpler fixed aspherical mirror components that can be manufactured using conventional precision optics techniques. The fixed aspherical surfaces are designed once and manufactured as rigid components, avoiding the high cost of deformable mirror actuators, control systems, and maintenance associated with active optics
3Device complexity
If classic aspherical components are used instead of deformable mirrors, then device complexity is reduced, but achieving high image quality across multiple focal lengths becomes difficult
Solution Approach 1:
The patent employs aspherical mirror surfaces with asymmetric curvature profiles characterized by conic constants (k) ranging from -0.5 to -2.0. These asymmetric surfaces are designed to correct spherical aberration, coma, and astigmatism at different focal lengths. The asymmetric aspherical shapes allow a single fixed component to maintain high optical quality across multiple focal settings without requiring complex deformable mechanisms
Solution Approach 2:
The patent introduces movable aspherical components as intermediaries between the primary mirror and the focal plane. These intermediate aspherical mirrors (secondary and tertiary) are positioned at specific locations along the optical axis to redirect and focus light, enabling the system to achieve different effective focal lengths while maintaining optimal image quality through their fixed aspherical surface geometries
4Volume of moving object
If the telescope is designed for compactness, then space application requirements are met, but optical path length and image quality control become more difficult
Solution Approach 1:
The patent employs a nested mirror configuration where the secondary mirror is positioned within the shadow of the primary mirror, and the tertiary mirror is positioned within the shadow of the secondary mirror. This nested arrangement allows the optical components to be compactly packaged within a small volume, with each mirror nested within the shadow region of the previous mirror, achieving space-compact design while maintaining the necessary optical path lengths for high-quality imaging at multiple focal lengths
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, high-quality telescope with a single detector that operates effectively across multiple focal lengths, achieving improved image quality and flexibility without the need for expensive deformable mirrors, while maintaining a compact form factor suitable for space applications.
Implementation Method 1
a first mirror M1 concave, a second convex mirror M2 and a third concave mirror M3
Implementation Method 2
The three mirrors being aspherical and of classic shape for such a telescope
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The invention relates to an anastigmat telescope with three aspheric mirrors comprising: - means (5) for linearly displacing the third mirror (M3) on the optical axis of the telescope (O) so as to vary the focal length of the telescope according to a plurality of focal lengths (fi) between at least a minimum focal length (fmin) and a maximum focal length (fmax), - a plurality of aspheric optical components (CAi) associated respectively with the plurality of focal lengths (fi), - the third mirror having a new taper (c'3) determined from an initial taper (c3), the new taper (c'3) being determined such that the telescope exhibits, without the presence of said aspheric components and for the minimum and maximum focal lengths, aberrations compensable by said aspheric components,- the position (PCAi) and the shape of the surface (Si) of each aspheric component being determined so as to correct said compensable aberrations of said telescope for the associated focal length (fi) and to optimize the image quality in the first focal plane of the telescope according to a predetermined criterion.