Zoom Lens Aperture Stop Dynamics for Compact Wide-Angle Design
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Solution Overview
Problem
Existing zoom lenses with high zoom ratios and wide angles of view face challenges in achieving both small size and high optical performance, as they tend to increase in size due to larger lens diameters and require complex movements to maintain optical quality across the image plane.
Innovation Solution
A zoom lens configuration with a first lens unit having positive refractive power that does not move for zooming, one or two moving lens units with negative refractive power, a positive lens unit with an aperture stop that moves for zooming, and a final lens unit with positive refractive power that does not move, where the intervals between lens units change for zooming, adhering to specific conditional expressions to optimize size and optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a wider angle of view is achieved by increasing the lens diameter of the first lens unit, then the angle of view is improved, but the size of the zoom lens increases
Solution Approach 1:
The patent applies dynamics by making the aperture stop movable during zooming. The aperture stop moves along the optical axis to different positions at wide angle, intermediate, and telephoto ends. This dynamic positioning allows the first lens unit to maintain a smaller diameter while still achieving wide angle of view at the wide angle end, because the aperture stop position is optimized for each zoom state rather than being fixed for all states.
Solution Approach 2:
The patent changes the position parameter of the aperture stop during zooming. By adjusting the aperture stop position to different locations (LSP at wide angle end, LSP' at intermediate end, LSP'' at telephoto end), the optical system can achieve wide angle of view with a smaller first lens unit diameter. This parameter change allows the same lens unit to serve multiple zoom states effectively.
2Temperature
If the focal length of the first lens unit is shortened to achieve wider angle of view, then the angle of view is improved, but the optical performance from center to edge of image plane deteriorates
Solution Approach 1:
The patent uses dynamics by moving the aperture stop to different positions during zooming. At the wide angle end, the aperture stop is positioned at LSP which is optimized for wide angle performance. At intermediate and telephoto ends, the aperture stop moves to LSP' and LSP'' respectively. This dynamic adjustment compensates for the shortened focal length of the first lens unit, maintaining optical performance uniformity across the image plane while achieving wide angle of view.
Solution Approach 2:
The aperture stop acts as an intermediary element that mediates between the first lens unit and the subsequent lens units. By positioning the aperture stop at optimal locations for different zoom states, it controls the light paths and ensures that the shortened focal length of the first lens unit does not compromise the optical performance uniformity across the image plane.
3Ease of operation
If the lens unit including the aperture stop moves to get closest to the object side at an intermediate point in zooming, then the zooming mechanism is optimized, but the achievement of wider angle of view becomes difficult
Solution Approach 1:
The patent applies dynamics by implementing a non-linear movement path for the aperture stop during zooming. Instead of following a simple linear path or getting closest to the object side at an intermediate point, the aperture stop moves to specifically optimized positions (LSP, LSP', LSP'') at wide angle, intermediate, and telephoto ends respectively. This dynamic positioning strategy maintains zooming mechanism efficiency while prioritizing wide angle of view achievement by ensuring the aperture stop is at the optimal position for wide angle performance.
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 allows for a zoom lens with a wide angle of view, small size, and high optical performance across the entire zoom range by controlling the position of the aperture stop and focal lengths of lens units, reducing size and weight while maintaining image quality.
Implementation Method 1
a first lens unit (L1) having a positive refractive power
Implementation Method 2
one or two moving lens units including a lens unit having a negative refractive power
Implementation Method 3
a positive lens unit including an aperture stop and configured to move for zooming
Implementation Method 4
a final lens unit having a positive refractive power
Data Source
AI summary
Provided is a zoom lens including, in order from an object side: a positive first unit not moving for zooming; one or two moving units move for zooming and including a negative unit; a negative unit moving for zooming; a positive unit including a stop and moving for zooming; and a positive final unit not moving for zooming. The distances on the optical axis, from surface, closest to the object side, of the first unit to a surface, closest to an image side, of the first unit, from the surface, closest to the object side, of the first unit to the stop at the wide angle end, from the surface, closest to the image side, of the first unit to the stop at the wide angle end, and the maximum distance from the surface, closest to the image side, of the first unit to the stop are appropriately set.