Focal Point Adjustment Device Using Camera Shake Feedback
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Solution Overview
Problem
Existing focal point adjustment devices face challenges in accurately adjusting the focal point due to variations in image height, camera shake, and relative positional shifts between image sensor components, leading to errors in focal point detection accuracy.
Innovation Solution
A focal point adjustment device and method that incorporate an image sensor with imaging and focal point detection pixels, a memory system for storing angular range and sensor characteristics, and a camera-shake preventing mechanism to correct camera shake by moving and rotating the image sensor, allowing for precise focal point adjustment calculations based on corrected image height information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the image sensor is moved for camera-shake correction, then camera shake is corrected, but image height changes causing focal point detection errors
Solution Approach 1:
The patent implements feedback by using a gyro sensor to detect camera shake in real-time, then feeding this information back to the image sensor driving section which adjusts the image sensor position accordingly. This closed-loop feedback mechanism enables effective camera-shake correction while the correction amount information is simultaneously used to compensate for image height changes in focal point detection calculations.
Solution Approach 2:
The patent changes the parameter of image height used in focal point detection calculations by adding a correction term based on the image sensor's movement amount. The corrected image height is calculated as: corrected image height = original image height + correction amount (where correction amount = movement amount × tan(incident angle)). This parameter adjustment eliminates the error introduced by camera-shake correction movement.
2Reliability
If the image sensor rotates for camera-shake correction, then camera shake is corrected, but relative positional relationship changes causing focal point detection errors
Solution Approach 1:
The gyro sensor provides real-time feedback on camera rotation, and this rotation information is fed back to calculate the change in relative positional relationship between the image sensor and optical components. The focal point detection section uses this feedback to adjust calculations and eliminate errors caused by rotational movement.
Solution Approach 2:
The patent adjusts the parameter of relative positional relationship by calculating the change based on rotation amount and incident angle, then applying this correction to the focal point detection. The correction accounts for how rotation changes the geometric relationship between the image sensor and the optical path, maintaining detection accuracy despite rotation.
3Ease of manufacture
If micro lens position shifts during manufacturing, then manufacturing is simplified, but focal point detection accuracy decreases
Solution Approach 1:
The patent changes the parameter of incident angle used in focal point detection calculations to account for micro lens position shifts. By measuring or estimating the actual incident angle of light flux considering the micro lens displacement, the system compensates for the positional error without requiring precise manufacturing. This allows simpler manufacturing while maintaining detection accuracy through parameter adjustment.
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 enables accurate focal point adjustment by accounting for image height variations and camera shake, improving detection accuracy and reducing errors caused by relative positional shifts, thereby enhancing the precision of autofocus systems.
Implementation Method 1
an image sensor having an imaging pixel and a focal point detection pixel, each of which receives a light flux having passed through a photographic lens and performs photoelectric conversion to output an image signal
Data Source
AI summary
There is provided a focal point adjustment device, comprising: a first memory to store information on an emission angular range of a light flux emitted toward an image sensor; a second memory to store the information on characteristics of the image sensor; a camera-shake preventing mechanism to correct camera shake by moving the image sensor, and to correct camera shake by rotating the image sensor in a plane perpendicular to the optical axis of the photographic lens and also output information on the movement and information on the rotation; and a calculation circuit to correct image height information at a range-finding position where the output of the focal point detection pixel is used, based on the information on the movement and the information on the rotation output by the camera-shake preventing mechanism, and calculate information for the focal point adjustment, based on the corrected image height information.