Optical Cap Reflective Collar for Downhole Illumination Uniformity
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Solution Overview
Problem
Existing inspection systems with wide angle lenses, such as fish-eye lenses, face issues with inadequate illumination of the peripheral field of view due to the configuration of light sources, leading to underexposure in these regions and overexposure in the central area when used in high temperature and high pressure environments like downhole settings.
Innovation Solution
An optical cap with a reflection surface on a tubular collar is integrated into the inspection assembly, deflecting a fraction of the light emitted by the light sources to illuminate the peripheral regions more evenly, while minimizing the likelihood of light entering the window element, and the cap is made from materials with matching thermal expansion coefficients to ensure durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wide angle lens is used to capture the entire field of view, then the coverage area is improved, but the illumination uniformity deteriorates due to inadequate light distribution to peripheral regions
Solution Approach 1:
A reflective collar is introduced as an intermediary element between the light source and the inspection target. The collar reflects light from the central region toward peripheral areas, mediating the light distribution to achieve more uniform illumination across the entire field of view captured by the wide angle lens
Solution Approach 2:
The reflective collar is positioned specifically in the peripheral region where illumination is inadequate. By applying the reflective property locally to this specific area, the solution targets the illumination deficiency without altering the overall wide angle lens configuration or requiring complex multi-source illumination systems
2Illumination intensity
If light sources are positioned to illuminate the field of view, then the illumination coverage is improved, but light may enter the window element and cause glare or interference
Solution Approach 1:
The reflective collar, which could potentially reflect light into the window element causing interference, is instead configured to reflect light away from the window element. The potential harmful effect of light reflection is converted into a beneficial effect by directing the reflected light toward the inspection target rather than toward the window element
3Ease of manufacture
If the optical cap is made from materials with different thermal expansion coefficients, then the manufacturing ease is improved, but the reliability deteriorates in high temperature environments due to thermal stress
Solution Approach 1:
The optical cap is constructed from materials with matching thermal expansion coefficients (such as Invar for the collar and sapphire or quartz for the window element). This principle ensures that both materials expand and contract at the same rate during temperature changes, preventing thermal stress and maintaining the integrity of bonded joints in high temperature downhole environments
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 provides more even illumination of the field of view, reducing the likelihood of under or overexposure in images captured by the camera, while maintaining the optical cap's integrity and functionality in harsh environments.
Implementation Method 1
there is provided on an external surface of the collar a reflection surface, an angle between the reflection surface and the axis of the collar being between 10° and 70°. The location of the reflection surface causes a part of a light beam emitted from a light source to be deflected
Implementation Method 2
a window element and a collar. The window element is made of a material having substantially the same coefficient of thermal expansion as the metal from which the collar is made
Implementation Method 3
The collar may be bonded to the window element by means of energy beam welding, solid state welding and/or brazing
Implementation Method 4
The collar may be bonded to the window element by means of energy beam welding, solid state welding and/or brazing
Data Source
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AI summary
This invention relates to an optical cap for an inspection assembly. In particular this invention relates to the provision of an optical cap that protects a camera lens of the inspection assembly. An optical cap for an inspection assembly comprises an optically clear dome-shaped window element and a metal collar attached to the window element, the collar including means for securing the optical cap to said inspection assembly, wherein the collar is bonded to the window element by means of brazing or welding.