Telecentric Encoder Aperture Integration for Alignment Precision

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Solution Overview

Problem

In photoelectric encoders with a double telecentric optical system, aligning the optical axis between separate lenses and apertures is challenging due to the need for additional components and space, making precise alignment difficult.

Innovation Solution

Integrating the aperture within the optical elements, such as lenses, eliminates the need for a separate aperture component, allowing for precise optical axis alignment between the lenses while reducing the number of components and simplifying assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the aperture is provided as a separate component between the first and second optical elements, then the optical system can control light transmission, but the optical axis alignment becomes difficult and the system size increases

Engineering Contradiction:

Improveoptical axis alignment precisionVSAvoidnumber of components and assembly complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The aperture is integrated into either the first optical element or the second optical element, merging two previously separate components (aperture and optical element) into one. This eliminates the need for separate aperture alignment and reduces the number of components, directly resolving the contradiction between alignment precision and device complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The optical element serves dual functions: both as an optical element for light transmission and focusing, and as an aperture for controlling light transmission angles. This multi-functionality eliminates the need for a separate aperture component, simplifying the system while maintaining precise optical axis alignment

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If the aperture is provided as a separate component, then light transmission can be controlled, but additional space is required for holding the aperture between the lenses

Engineering Contradiction:

Improveoptical axis alignment precisionVSAvoidoptical system size

Core Design Contradiction:

Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The aperture is merged with the optical element, eliminating the need for additional space to hold a separate aperture component. This integration directly reduces the optical system size while maintaining precise alignment capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The aperture structure is nested within the optical element structure, with the aperture forming part of the optical element's architecture. This nesting eliminates the need for additional external space while maintaining the aperture's light transmission control function

Inventive Principle:

Principle #7Nested doll (Nesting)

3Ease of manufacture

If separate components are used for lens and aperture, then the optical system can be assembled, but the axis alignment of the optical system becomes difficult

Engineering Contradiction:

Improveassembly feasibilityVSAvoidoptical axis alignment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The aperture and optical element are merged into a single integrated component, reducing the number of assembly steps from aligning multiple separate components to aligning fewer integrated components. This improves both assembly ease and alignment precision simultaneously

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

This configuration enables high-precision optical axis alignment and reduces harmonic distortion in the light intensity distribution, improving signal detection efficiency and reducing the complexity of the optical system.

Implementation Method 1

restrict a passage of light rays each having an angle equal to or larger than a third diffraction angle among diffracted lights generated by the grid scale

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

telecentric optical unit which is provided between the scale and the light receiving portion and forms the image of the grid scale on the light receiving portion

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS10088340B2Telecentric photoelectric encoder including aperture in face of optical element

Publication Date: 2018.10.02 MITUTOYO CORP

AI summary

A photoelectric encoder of the present invention includes: a scale which includes a grid scale; a light emitting portion which irradiates light toward the scale; a light receiving portion which detects an image of the grid scale of the scale; and a telecentric optical unit which is provided between the scale and the light receiving portion and forms the image of the grid scale on the light receiving portion, wherein the telecentric optical unit includes a first optical element which is disposed near the scale, a second optical element which is disposed near the light receiving portion in relation to the first optical element and is disposed so that a gap is formed between the second optical element and the first optical element, and an aperture which is provided in at least one of a face near the second optical element in the first optical element and a face near the first optical element in the second optical element.