Diffraction Grating Return Mirror for Wide FOV Jitter Sensing
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Solution Overview
Problem
Conventional optical sensors with planar reflective return mirrors face limitations when large pointing motions result in jitter signals being reflected outside the field of view, leading to incomplete jitter correction and reduced image quality.
Innovation Solution
The use of a diffraction grating as a jitter signal return component within the optical sensor system, which reflects and diffracts the jitter source signal to generate multiple orders, ensuring that at least one order is returned within the field of view of the position sensor, enabling accurate jitter measurement and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a planar reflective return mirror is used, then the optical path is simple and alignment is easy, but during large pointing motions the jitter signal is reflected outside the field of view and cannot be detected
Solution Approach 1:
The patent changes the fundamental optical parameter of the return component from planar reflection to diffraction grating operation. The diffraction grating equation d(sinα + sinβ) = nλ allows the return signal to be directed at different angles based on the diffraction order, enabling the system to maintain the return signal within the field of view during large pointing motions while preserving alignment simplicity.
Solution Approach 2:
The patent introduces a new dimension to the optical path by using diffraction orders. Instead of relying solely on the incident angle for signal return, the diffraction grating creates multiple return paths corresponding to different diffraction orders (n=0, ±1, ±2, ...), providing additional spatial dimensions for signal recovery within the field of view.
2Adaptability or versatility
If the field of view is increased to accommodate large pointing motions, then the jitter signal can be maintained within view, but the imaging resolution and precision are reduced
Solution Approach 1:
The patent segments the return signal into multiple diffraction orders, where each order can be independently detected and processed. This allows the system to maintain a narrow field of view for high-resolution imaging while the diffraction grating redirects the jitter signal through specific orders that remain within the detector's field of view, thus preserving both resolution and adaptability.
3Adaptability or versatility
If a diffraction grating is used instead of a planar mirror, then multiple diffraction orders provide redundant signal paths for large pointing motions, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The diffraction grating serves multiple functions simultaneously: it acts as a beam splitter, a wavelength separator, and a directional controller all in one component. By providing multiple diffraction orders, a single component achieves what would otherwise require multiple mirrors and beam splitters, actually reducing overall system complexity while improving signal return reliability.
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 solution allows for reliable jitter signal return and accurate measurement, even during large pointing motions, enhancing the ability to correct image jitter and maintain image quality in optical sensors.
Implementation Method 1
a diffraction grating positioned about the foreoptics assembly. The diffraction grating can be operable to reflect and diffract the jitter source signal
Implementation Method 2
The diffraction grating can be operable to reflect and diffract the jitter source signal
Data Source
AI summary
An optical sensor comprises foreoptics configured to receive an image signal, an image optic operable to focus the image signal, at least one focal plane array (FPA) configured to detect the image signal, and a jitter stabilization system. The jitter stabilization system can comprise a transmitter configured to transmit a jitter source signal to the foreoptics and a position sensor configured to receive a jitter return signal. The position sensor can be positioned at a shared focus with the at least one FPA. The optical sensor further comprises a diffraction grating operable to reflect and diffract at least a portion of the jitter source signal. The jitter return signal received at the position sensor comprises at least a portion of the reflected and diffracted jitter source signal.