Optical Receiving Unit Mounting for Stable Detector Alignment

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Solution Overview

Problem

Existing optical position measuring systems face inaccuracies due to mechanical and thermal stress, which can cause deformation and changes in the distance and position between the detector and scanning grid, leading to measurement errors.

Innovation Solution

An optical receiving unit with a self-centering compensation element and solid-state joint bipods is designed to maintain a stable relative position of the detector to the scanning grid, preventing lateral movement and rotation caused by mechanical and thermal influences, and ensuring the measuring cell is kinematically mounted to minimize deformation and thermal expansion effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the measuring cell is rigidly fixed to the mounting housing, then the mounting is stable, but mechanical stress causes deformation and changes in distance/position between detector and scanning grid

Engineering Contradiction:

Improvemounting stabilityVSAvoidposition determination accuracy

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

Solid-state joint bipods are introduced as intermediary mounting elements between the measuring cell and the mounting housing. These bipods provide a kinematically determined mounting that allows controlled movement and deformation absorption, preventing stress transmission to the detector-scanning grid system while maintaining stable positioning.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The mounting system is designed to accommodate parameter changes (thermal expansion, mechanical deformation) by allowing controlled movement through the solid-state joint bipods. The system transitions from a rigid fixed mounting to a compliant mounting that adapts to dimensional changes without compromising measurement accuracy.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the detector is rigidly mounted on the base plate, then the structure is simple, but thermal expansion causes lateral position changes and rotation

Engineering Contradiction:

Improvemounting structure simplicityVSAvoiddetector position accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

A self-centering compensating element is introduced as an intermediary between the detector and the base plate. This element absorbs thermal expansion and mechanical deformation, maintaining the detector's lateral position and orientation relative to the scanning grid while allowing the base plate to deform freely.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The self-centering compensating element is specifically designed to accommodate thermal expansion of the base plate. It allows the base plate to expand and contract with temperature changes while maintaining the detector's precise position, effectively decoupling the detector from thermal effects.

Inventive Principle:

Principle #37Thermal expansion

3Strength

If the measuring cell is attached by screwing, then the assembly is secure, but mechanical stress deforms the measuring cell and scanning grid

Engineering Contradiction:

Improveassembly securityVSAvoidmeasuring cell geometry accuracy

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

Solid-state joint bipods serve as intermediary mounting elements that replace direct screwing of the measuring cell to the housing. They provide secure attachment while accommodating dimensional changes and preventing stress transmission that would deform the measuring cell and scanning grid.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The solid-state joint bipods are designed to beforehand cushion and absorb mechanical stresses before they can reach the measuring cell. This preventive approach protects the precision components from deformation while maintaining secure assembly.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 design minimizes measurement errors by maintaining a stable relative position of the detector to the scanning grid, preventing bending and deformation, and ensuring accurate spatial position determination despite mechanical and thermal influences.

Implementation Method 1

when thermal or mechanical influences act on the base plate

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

A deformation of the measuring cell can result in a changed distance between the detector and the scanning grid

Methodology Applied

Scientific EffectMechanical deformation: Deformation

Implementation Method 3

Similar effects can also be caused by temperature changes

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4145083B1Optical receiving unit

Publication Date: 2023.12.20 DR JOHANNES HEIDENHAIN GMBH

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AI summary

The present invention relates to an optical receiving unit for a position measuring system for determining spatial position information. The receiving unit comprises a measuring cell consisting of a base plate, a transparent top plate with a scanning grid, one or more spacers between the base plate and the top plate, and an optoelectronic detector whose light-sensitive surface is oriented towards the top plate. The detector is arranged on the base plate of the measuring cell via a self-centering compensating element.