Cassegrain Telescope Mounting Plate Positioning References

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Solution Overview

Problem

The assembly of telescopes, particularly those of the Cassegrain type, is complicated due to the challenging operation of mounting the secondary mirror relative to the primary mirror, which can result in mechanical stresses and deformations, affecting the optical quality.

Innovation Solution

A telescope design featuring a fixing plate with positioning references for the primary mirror and a secondary mirror with centering engraving, along with a support system that includes a primary and secondary crown with mechanical decoupling elements and arms to reduce stress and vibration transmission, facilitating alignment and attachment using optical quality machining and structural adhesives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional mounting methods are used to assemble the telescope, then the assembly process is completed, but the operation becomes complicated and mechanical stresses cause mirror deformations

Engineering Contradiction:
Improveassembly processVSAvoidmounting operation complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

Positioning references (machined surfaces, bore centers, engagement features) are pre-formed on the mounting plate and secondary mirror support during manufacturing. This preliminary action eliminates the need for complex field alignment operations, allowing the secondary mirror to be positioned accurately through simple mechanical engagement rather than delicate manual adjustment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex mechanical adjustment mechanisms with a simplified system based on precision-machined positioning references. Instead of using adjustable mounts requiring manual alignment, the design uses pre-formed geometric references (flat surfaces, bore centers, spherical caps) that guide the secondary mirror into correct position through pure mechanical engagement, reducing operational complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If traditional mounting methods are used to assemble the telescope, then the assembly process is completed, but mechanical stresses cause mirror deformations affecting optical quality

Engineering Contradiction:
Improveassembly processVSAvoidoptical quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent extracts the stress-causing elements from the mounting system by using a minimal number of strategically placed fixing elements with precision-machined positioning references. These references (flat surfaces, bore centers, engagement features) are designed to locate and secure the secondary mirror without applying concentrated mechanical stresses that would deform the mirrors, thereby maintaining optical quality while simplifying assembly.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The positioning references act as intermediaries between the mounting plate and the secondary mirror support. These pre-formed geometric features (machined surfaces, bore centers, spherical caps) mediate the connection by providing precise location and orientation without requiring complex stress-bearing mechanical adjustments, thus preserving optical quality during assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If positioning references are added to the mounting plate, then assembly is simplified, but the device complexity increases

Engineering Contradiction:
Improvepositioning operationVSAvoidmounting plate features
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The positioning references on the mounting plate serve multiple functions simultaneously: they provide mechanical support for the secondary mirror support, establish precise angular orientation through machined flat surfaces, define lateral position through bore centers, and set the distance from the primary mirror through spherical cap geometry. This multi-functionality simplifies the overall positioning operation without requiring separate adjustment mechanisms for each degree of freedom.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges multiple positioning functions into a single integrated mounting plate design. Instead of using separate adjustment mechanisms for each positioning parameter (angular orientation, lateral position, distance), the design combines all these functions into pre-formed geometric references (flat surfaces, bore centers, spherical caps) that simultaneously provide all necessary positioning information, reducing operational steps.

Inventive Principle:
Principle #5Merging (Combining)

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

Simplifies the assembly process, reduces mechanical stresses on the mirrors, and improves optical performance by minimizing deformation and vibration transmission, especially in vehicle-mounted telescopes.

Implementation Method 1

The third section is received in the bearing with a sliding fit and is glued into the bearing by means of a structural glue

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

the positioning references are obtained by optical quality machining and include a face perpendicular to an optical axis of the telescope to form an inclination reference, a central bore to form a centering reference

Methodology Applied
Scientific EffectOptical measurement: Optical Tweezers

Data Source

PatentEP3673312B1Telescope that is easier to mount and method for adjusting such a telescope
Publication Date: 2023.01.25 SAFRAN ELECTRONICS & DEFENSE (FR)
  • EP3673312B1 patent drawingFigure 1
  • EP3673312B1 patent drawingFigure 2~4
  • EP3673312B1 patent drawingFigure 5~6

AI summary

The invention relates to a telescope comprising an attachment plate (1), a primary mirror (100) borne by a front face (2) of the plate, and a secondary mirror (200) held opposite the primary mirror by a support (300), characterized in that the telescope is of the Cassegrain type and the plate (1) has a rear surface (3) having positioning references for the telescope with respect to an image capturing device (400) disposed opposite the rear face.