Zoom Lens Peripheral Light Correction via Perpendicular Sensor Shift
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Solution Overview
Problem
Existing imaging apparatuses face challenges in efficiently using effective pixels of solid-state imaging devices while correcting object image position variations during zooming, leading to uneven light quantity on the periphery of the object image.
Innovation Solution
A high zoom ratio zoom lens system with a configuration that includes a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group, a fourth lens group, and a fifth lens group, where the first, second, third, and fourth lens groups are moved along the optical axis, and a solid-state imaging device is moved perpendicular to the optical axis to correct image position variations, with a shield member limiting peripheral light rays using an aperture portion, satisfying specific conditional expressions for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the solid-state imaging device is moved along the optical axis to correct object image position variation during zooming, then effective pixels can be efficiently used, but light quantity becomes uneven on the corner of the object image
Solution Approach 1:
The patent extracts the function of correcting object image position variation from the solid-state imaging device movement along the optical axis, and instead implements it by moving the imaging device in the shooting direction (perpendicular to optical axis). This separation allows the optical axis movement to be eliminated, preventing peripheral light quantity unevenness while maintaining effective pixel utilization through perpendicular direction correction.
Solution Approach 2:
The patent inverts the conventional correction approach by moving the imaging device perpendicular to the optical axis (in the shooting direction) rather than along the optical axis. This reverse approach achieves the same correction effect while avoiding the side effect of peripheral light quantity unevenness, as the aperture stop remains properly positioned relative to the optical axis.
2Productivity
If the solid-state imaging device is moved perpendicular to the optical axis to correct object image position variation, then effective pixels are efficiently used and peripheral light quantity is maintained, but device complexity increases due to additional moving mechanisms
Solution Approach 1:
The patent makes the imaging device movement mechanism universal by enabling it to perform both vibration reduction (perpendicular to optical axis) and object image position correction (in the shooting direction) functions. This multi-functionality eliminates the need for separate correction mechanisms, reducing overall device complexity while maintaining effective pixel utilization.
Solution Approach 2:
The patent merges the vibration reduction function and object image position correction function into a single imaging device movement mechanism. By combining these functions, the patent reduces the number of separate mechanisms required, thereby reducing device complexity while achieving both effective pixel utilization and peripheral light quantity uniformity.
3Illumination intensity
If a shield member with aperture portion is added to limit peripheral light rays, then peripheral light quantity ratio is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent introduces the aperture stop as an intermediary element that naturally limits peripheral light rays. By utilizing this existing optical component with an aperture portion, the patent achieves improved peripheral light quantity ratio without requiring a separate shield member, thereby avoiding increased manufacturing difficulty and device complexity.
Solution Approach 2:
The patent makes the aperture stop multi-functional by using it both for its conventional purpose (controlling light intensity and depth of field) and for limiting peripheral light rays to improve peripheral light quantity ratio. This eliminates the need for a dedicated shield member, simplifying manufacturing while achieving the desired optical effect.
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 configuration enables efficient use of effective pixels and maintains an excellent peripheral light quantity ratio during vibration reduction, preventing coma and curvature of field issues, thus enhancing image quality.
Implementation Method 1
a driving member that moves the solid-state imaging device in a direction substantially perpendicular to the optical axis; a control member that controls the driving member in order to correct variation in the position of the object image
Implementation Method 2
a shield member with an aperture portion for limiting bundle of rays incident on the periphery of the most object side lens in the first lens group
Implementation Method 3
upon zooming from a wide-angle end state to a telephoto end state, the first lens group, the second lens group, the third lens group, and the fourth lens group being moved along an optical axis
Data Source
AI summary
Providing an imaging apparatus capable of efficiently using effective pixels of a solid-state imaging device, and securing excellent peripheral light quantity of an image even upon vibration reduction. The imaging apparatus comprising: a high zoom ratio zoom lens 2 including, in order from the object, a first positive group, a second negative group, a third group, a fourth group, and a fifth group, upon zooming the first through fourth groups are moved along an optical axis; an imaging device capturing an image formed by the lens 2; a detector detecting variation in an image position; a driver moving the imaging device substantially perpendicularly to the optical axis; a controller controlling the driver for correcting variation in the image position; and a shield with an aperture for limiting bundle of rays incident on the periphery of the most object side lens in the lens 2; and given condition is satisfied.