Common-Aperture Optical System Boresight Alignment

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Solution Overview

Problem

Existing optical systems face challenges in maintaining precise boresight alignment of light sensors and light sources, especially in adverse environments, and struggle to combine different optical signals of varying wavelengths using a single telescope.

Innovation Solution

A common-aperture reflective telescope with a beam splitter and diverger lens is used to align and correct both input and output light beams, ensuring precise boresight alignment and avoiding chromatic aberration, while maintaining a compact and lightweight design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two separate telescopes are used for light collection and light transmission, then the functions are performed separately, but maintaining parallel boresight alignment becomes challenging under thermal expansion and environmental conditions

Engineering Contradiction:
Improveboresight alignment stabilityVSAvoidalignment maintenance complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the light collection telescope and light transmission telescope into a single integrated optical system with a common aperture and shared optical path. The beam combiner merges the incoming light path and outgoing light path, allowing both functions to be performed through one telescope structure, thereby eliminating alignment drift between separate telescopes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single telescope structure serves multiple functions: it collects incoming light for the light sensor, transmits outgoing light from the light source, and provides a common boresight for both functions. The beam combiner enables the system to handle both incoming and outgoing beams through the same optical path, achieving multi-functionality in a unified structure.

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

2Device complexity

If a single telescope with common aperture is used for both light sensing and light transmission, then the system is more compact, but it becomes difficult to handle different optical signal characteristics such as different wavelengths and intensities

Engineering Contradiction:
Improvesystem structure simplicityVSAvoidoptical signal compatibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The beam combiner acts as an intermediary optical element that separates and directs different optical signals. It uses wavelength-selective properties to direct the outgoing light beam (typically laser wavelength) through the telescope while allowing the incoming light beam (sensor wavelength) to pass through to the sensor, enabling the single telescope to handle different optical signal characteristics.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The beam combiner introduces wavelength-specific optical properties at different locations in the optical path. Different portions of the spectrum are handled differently: the outgoing laser light is reflected by the beam combiner toward the telescope, while the incoming sensor light passes through the beam combiner to the sensor, allowing each wavelength to be optimized for its specific function.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If reflective optics are used in the common aperture telescope, then chromatic aberration is avoided for different wavelengths, but the optical path management becomes more complex

Engineering Contradiction:
Improvechromatic aberration correctionVSAvoidoptical path management
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the reflective telescope optics with the beam combiner in a unified optical path. The reflective mirrors handle wavelength-independent focusing while the beam combiner manages wavelength-specific beam routing, combining the advantages of reflective optics (no chromatic aberration) with beam splitting capabilities in a single integrated design.

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

The solution achieves precise aiming and alignment of light beams under various conditions, reducing the potential for air breakdown and maintaining alignment, even with different wavelengths, resulting in a more compact and efficient optical system.

Implementation Method 1

A beam splitter intersects the beam path so that the beam path is incident upon the beam splitter

Methodology Applied
Scientific EffectBeam splitting: Reflection

Implementation Method 2

A diverger corrects at least one of the input light beam and the output light beam

Methodology Applied
Scientific EffectLight divergence correction: Lens

Implementation Method 3

a reflective telescope including at least two mirrors

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2115515B1Common-aperture optical system incorporating a light sensor and a light source
Publication Date: 2017.05.17 RAYTHEON CO
  • EP2115515B1 patent drawingFigure 1
  • EP2115515B1 patent drawingFigure 2
  • EP2115515B1 patent drawingFigure 3

AI summary

A common-aperture optical system (20) includes a reflective telescope (22) having a common boresight (24), an entrance pupil (26), an exit pupil (28), and a beam path (30) extending from the entrance pupil (26) to and beyond the exit pupil (28). A beam splitter (32) intersects the beam path (30) so that the beam path (30) is incident upon the beam splitter (32). A light sensor (34) is positioned to receive an input light beam (36) traveling along the beam path (30) after the beam path (30) intersects the beam splitter (32) and passes the exit pupil (28) of the reflective telescope (22). A light source (38) produces an output light beam (40) incident upon the beam splitter (32) and positioned to inject the output light beam (40) into an inverse of the beam path (30) and toward the entrance pupil (26) of the reflective telescope (22). A diverger (42) corrects at least one of the input light beam (36) and the output light beam (40).