Rotary Shutter Assemblies for Uniform Imaging Photometer Exposure
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Solution Overview
Problem
Conventional mechanical shutters in imaging devices, such as iris shutters, introduce errors due to uneven exposure times across the image sensor, and require frequent maintenance, making them unsuitable for applications requiring short exposure times and high accuracy.
Innovation Solution
A rotary shutter assembly with pivotable apertures that move at a constant angular speed to ensure uniform exposure times across the image sensor, minimizing errors and reducing maintenance needs by eliminating moving parts that rub against each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an iris shutter is used to control exposure time, then the shutter can mechanically block light, but different portions of the image sensor are exposed for different lengths of time introducing measurement errors
Solution Approach 1:
The shutter is divided into multiple independent segments or blades that can be controlled individually. By segmenting the shutter aperture into multiple controllable portions, the system can ensure that all segments open and close simultaneously, achieving uniform exposure across the entire image sensor while maintaining precise exposure time control.
2Reliability
If an iris shutter is used with many moving parts, then the shutter can control light exposure, but the moving parts constantly rubbing against each other require significant maintenance and replacement
Solution Approach 1:
The invention extracts or removes the problematic moving parts from the shutter system. By eliminating the mechanical rubbing components that require maintenance, the system achieves reliable shutter functionality through a simplified design that prevents wear and tear on critical components.
Solution Approach 2:
The patent replaces the traditional mechanical iris shutter system with an alternative mechanism that eliminates rubbing moving parts. This substitution maintains the light control functionality while removing the maintenance burden associated with mechanical wear, potentially using electronic or hybrid control methods.
3Measurement precision
If longer exposure times are used to minimize measurement errors from iris shutter opening/closing times, then exposure accuracy improves, but the system becomes unsuitable for applications requiring short exposure times
Solution Approach 1:
The shutter system incorporates dynamic control capabilities that allow it to adapt to different exposure time requirements. By making the shutter response time adjustable and optimizing the opening/closing dynamics, the system achieves both short exposure times for speed and long exposure times for accuracy when needed, eliminating the trade-off between speed and precision.
Data Source
AI summary
Rotary shutter assemblies for imaging photometers and methods for using such shutters are disclosed herein. In one embodiment, for example, a method for capturing an image with an imaging photometer can include positioning a rotary shutter having an aperture at a first position such that the shutter blocks light traveling along an optical axis from a light source being measured to an image sensor of the photometer. The method can include pivotably moving the shutter at a generally constant angular speed to a second position with the aperture aligned with the optical axis to expose at least a portion of the image sensor to the light for a first predetermined exposure time. After exposing each portion of the image sensor to the light for the first exposure time, the method can include pivotably moving the shutter at the angular speed to a third position such the aperture is not aligned the optical axis, and then pivotably moving the shutter from the third position back to the first position without rotating the shutter 360 degrees.