Aperture-Stop Control for Dark Exposure Light Leakage
Solution Overview
Problem
Conventional dark exposure control methods in cameras are inadequate in reducing light entry during dark exposures, especially when strong light sources like car headlights are present, leading to increased noise in images due to dark current generation.
Innovation Solution
A dark exposure control device with an aperture-stop mechanism that adjusts the light incidence on the imaging device, minimizing the opening degree during dark exposures, even when strong light enters the lens, using a processor to detect image signals and control the aperture-stop driving circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If only the shutter is closed to perform dark exposure, then the dark exposure can be carried out, but light may still leak into the imaging device through the closed shutter when strong light enters the photographing lens
Solution Approach 1:
The patent introduces an aperture stop as an intermediary element between the lens and the imaging device. During dark exposure, the aperture stop closes its opening to block light paths that would otherwise leak through the shutter mechanism, providing an additional layer of light isolation without requiring fundamental changes to the shutter system.
Solution Approach 2:
The patent divides the light blocking function into two separate components: the shutter (which blocks light during normal operation) and the aperture stop (which provides additional blocking during dark exposure). This segmentation allows each component to be optimized for its specific function while working together to achieve complete light isolation.
2Object-affected harmful factors
If the aperture stop opening degree is reduced during dark exposure, then light entry is dramatically reduced, but the aperture stop must be actively controlled by an additional driving processor
Solution Approach 1:
The aperture stop is designed to serve multiple functions: during normal photography it controls the amount of light for proper exposure, and during dark exposure it closes to block light leakage. This multi-functionality allows the same component to address light control needs in different operational modes without requiring separate dedicated mechanisms.
Solution Approach 2:
The dark exposure control processor monitors the exposure conditions and automatically adjusts the aperture stop opening degree accordingly. When dark exposure is detected, the processor signals the aperture stop to close, providing automated feedback control that reduces manual intervention and simplifies user operation despite the added component.
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 approach significantly reduces light entry into the camera, thereby minimizing noise and improving image quality during long-exposure photography, particularly in mirrorless-type cameras.
Implementation Method 1
The aperture-stop adjusts the amount of light incident on the imaging device
Implementation Method 2
an imaging device and a shutter for controlling the exposure of the imaging device
Data Source
AI summary
A dark exposure control device comprises a dark exposure performing processor, an aperture-stop, and an aperture-stop driving processor. The dark exposure performing processor detects an image signal generated by an imaging device while the shutter is closed. The aperture-stop adjusts the amount of light incident on the imaging device. The aperture-stop driving processor adjusts the opening degree of the aperture-stop to smaller than the opening degree set for a main exposure while the dark exposure performing processor is operated.