Tapered Sapphire Light Guide for Night Vision Image Combining
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Solution Overview
Problem
Current light guiding devices for combining images from image intensifiers and thermal imagers face challenges such as reduced field of view and sensitivity due to opaque housings, and intensity issues from projected light swamping captured light.
Innovation Solution
A light guiding device with an elongate solid body of high refractive index material, such as sapphire, that tapers from a wider end to a narrower end, eliminating the need for an opaque housing and incorporating a reflector to direct light with minimal obstruction, along with a control unit to adjust light intensity based on ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an opaque housing is used to provide structural integrity and shield the reflector, then structural stability is improved, but field of view obstruction increases and sensitivity is reduced
Solution Approach 1:
The patent replaces the traditional opaque housing with a transparent or translucent housing that allows light to pass through. This thin-film approach maintains structural integrity while eliminating field of view obstruction, enabling the housing to serve both protective and optical transmission functions simultaneously.
Solution Approach 2:
The patent removes the opaque housing component entirely and replaces it with a transparent housing structure. This extraction of the opaque material eliminates the trade-off between structural stability and field of view, as the transparent housing provides structural support without blocking light paths.
2Illumination intensity
If the projector intensity is increased to improve visibility of projected information, then projected image visibility is improved, but captured light is swamped and image quality deteriorates
Solution Approach 1:
The patent employs temporal modulation where the projector operates in periodic pulses rather than continuous operation. During projection pulses, the intensifier is suppressed, and during capture intervals, the projector is turned off. This periodic action allows high-intensity projection without swamping the captured light, as the two functions occur at different times.
Solution Approach 2:
The patent implements dynamic control of the projector intensity and timing based on ambient light conditions and capture requirements. The system automatically adjusts projection intensity and timing to optimize both projected visibility and captured image quality, transitioning between projection and capture modes as needed.
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 reduces the overall thickness and weight of the device, minimizes field of view obstruction, and ensures clear differentiation between projected and captured light, enhancing night vision performance by combining images effectively across different wavelength ranges.
Implementation Method 1
an elongate light transmitting solid body, the body tapering from a wider end to a narrower end
Implementation Method 2
a reflector provided adjacent to the narrower end, the reflector adapted to receive said incident light from the exit surface and reflect said incident light away from the device
Data Source
AI summary
A light guiding device is operable to receive incident light emitted by a light source through a capture surface. The received light exits the light guiding device through an exit surface provided adjacent to and aligned with an aperture of light receiver. In this manner, light from the light source can be inserted into the receiver where it may be combined with additional incident light captured by the receiver. The light source might be a projector and the light projected may correspond to operational data relating to the operation of the receiver or images corresponding to data captured by a further receiver device operating with a different form of sensor or in a different region of the spectrum. In order to improve the composite image observed by a user of the light receiving device, the operation of the light source can be controlled to vary the intensity of the light emitted. In one example, this variation can be in response to the ambient light level, as sensed by a suitable sensor. An additional or alternative variation is to vary the intensity in a pulsed manner between a peak and a low level.