Optical Coupling for Intensifier Tube Digital Sensor Integration
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Solution Overview
Problem
Current low light level image capture systems using intensifier tubes produce analog images that cannot be directly used by digital image processing, storage, and transmission systems, and alternative solutions like replacing the tube with digital sensors or optical coupling face challenges such as reduced sensitivity, resolution, and complex optical coupling issues.
Innovation Solution
A method for optimizing the optical coupling between the intensifier tube and a digital sensor using a dioptric or telecentric coupling optic with specific lens configurations and filtering to maintain sensitivity and resolution while minimizing numerical aperture and diffraction, allowing for efficient digital image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical coupling is done by means of a bundle of optical fibers, then the advantages of intensifier tube are combined with those of digital image sensor, but geometric transmission losses, Fresnel losses, and resolution losses occur
Solution Approach 1:
The patent introduces a specialized coupling optic as an intermediary component between the intensifier tube and digital sensor. This coupling optic includes specific lens elements (first positive lens, negative lens, second positive lens) arranged in a particular configuration that acts as a mediator to transfer light with minimal loss, avoiding the transmission problems of optical fiber bundles while enabling digital compatibility
Solution Approach 2:
The patent optimizes the coupling optic by carefully selecting and adjusting parameters such as focal lengths of lens elements, distances between them, and numerical aperture. These parameter changes enable the system to achieve both high transmission efficiency and compatibility with digital sensors, resolving the contradiction between maintaining signal strength and achieving digital integration
2Measurement precision
If a refractive or catadioptric optical transport is used, then desired resolution and optimized transmission can be obtained, but optical quality, size and cost constraints become contradictory
Solution Approach 1:
The patent applies local quality by designing the coupling optic with different lens elements having specific properties at different positions. The first positive lens, negative lens, and second positive lens each have tailored characteristics optimized for their specific location in the optical path, allowing high resolution where needed while controlling overall system complexity
Solution Approach 2:
The coupling optic is segmented into multiple discrete lens elements rather than using a single complex element. This segmentation allows each lens to be optimized for its specific function while simplifying manufacturing and assembly, thereby achieving high resolution without excessive device complexity
3Adaptability or versatility
If digital sensors replace intensifier tubes, then digital image processing capability is achieved, but sensitivity to low illumination and resolution are reduced
Solution Approach 1:
The patent merges the advantages of both intensifier tubes and digital sensors by combining them in a coupled system. The intensifier tube maintains its superior low-light sensitivity and resolution capabilities, while the coupling optic transfers the amplified image to the digital sensor, thereby achieving both digital processing capability and high performance in low-light conditions
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 optimized optical coupling system achieves high sensitivity and resolution, enabling real-time digital image capture with minimal degradation, suitable for low light level applications and compatible with digital processing and storage.
Implementation Method 1
The principle of operation of an intensifier tube is to form a low level light image on the surface of a photocathode. This emits electrons in proportion to the photons received.
Implementation Method 2
These electrons are amplified by means of a micro-channel pancake and a high voltage.
Implementation Method 3
At the output of the amplification, the electrons are received by a phosphorescent screen which gives an amplified image of the initial image.
Data Source
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AI summary
The general field of the invention is that of methods for implementing a coupling optic (3) for a low-light image capture system. The image capture system comprises a light intensifier (2), the coupling optic, and a matrix photosensitive sensor (4).The method for implementing the coupling optics according to the invention comprises the following steps: Step 1: Calculation of the optimal magnification of the coupling optics; Step 2: Calculation of the aperture number of the coupling optics so that the diameter of the diffraction spot, the image of a point object given by the coupling optics on said phosphorescent screen, is less than or on the order of magnitude of the dimensions of the pixels of the photosensitive sensor; Step 3: Calculation of the amplification gain of the intensifier so that, for a minimum luminance of the captured image, the luminous flux received by each elementary pixel is equal to or greater than the minimum flux given by the sensitivity of the photosensitive sensor.