Zoom Lens Angle of View Stability via Segmented Focus Units
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving high optical performance and reducing angle of view fluctuations during zooming and focusing, particularly due to difficulties in electrification and weight distribution, as well as limitations in maintaining optical quality across the entire zoom range.
Innovation Solution
A zoom lens configuration that includes a first lens unit with negative refractive power, an intermediate group with multiple lens units, an aperture stop, and a rear group, where the intermediate group comprises two focus units that move during focusing, allowing for precise control of focal length and angle of view changes while maintaining a stable overall length and low zoom torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the focus lens in the first lens unit is moved during focusing, then the angle of view can be corrected, but the lens unit has large diameter and heavy weight making electrification difficult
Solution Approach 1:
The patent extracts the focusing function from the first lens unit (which contains the heavy focus lens) and relocates it to the second lens unit. Specifically, the second lens unit is configured to move along the optical axis during focusing, while the first lens unit remains stationary. This separation allows angle of view correction without moving the heavy lens, enabling electrification and reducing mechanical complexity.
Solution Approach 2:
The patent introduces the second lens unit as an intermediary element that performs the focusing function. Instead of directly moving the heavy focus lens in the first unit, the system uses the second lens unit's movement to achieve the same optical effect. This intermediary approach allows angle of view stabilization without the drawbacks of moving the heavy lens.
2Stability of the object's composition
If a zoom cam is used for correction during zooming, then angle of view changes can be corrected, but the configuration cannot perform electric zoom
Solution Approach 1:
The patent replaces the mechanical zoom cam system with an electrically controlled lens movement mechanism. The distances between lens units are adjusted using electric motors or actuators that move the lens units along the optical axis during zooming. This substitution enables automated electric zoom while maintaining angle of view correction through programmed lens position adjustments.
Solution Approach 2:
The patent implements dynamic control of lens unit positions during zooming operations. Rather than using a fixed mechanical cam profile, the system dynamically adjusts the distances between lens units based on real-time zoom position feedback. This allows flexible, electrically controlled angle of view correction across the entire zoom range.
3Stability of the object's composition
If the first lens unit is moved during zooming, then angle of view correction can be achieved, but the overall lens length changes and zoom torque increases
Solution Approach 1:
The patent segments the zooming function across multiple lens units (first, second, and third) rather than relying on movement of the entire first lens unit. Each lens unit contributes to the zooming action through coordinated movement, allowing angle of view correction while maintaining a more compact overall structure and reducing the torque required for zooming operations.
Solution Approach 2:
The second and third lens units serve as intermediaries that facilitate zooming and angle of view correction without requiring movement of the heavy first lens unit. By distributing the corrective function across these intermediate lens units, the system achieves the desired optical correction while maintaining stable overall length and reducing mechanical stress.
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 achieves high optical performance with minimal aberrational fluctuations and angle of view changes, enabling effective image capture across the entire zoom range, suitable for both digital still cameras and video cameras, and is compatible with electric zoom attachments.
Implementation Method 1
a first lens unit B1 having negative refractive power
Implementation Method 2
an intermediate group having positive refractive power, the intermediate group including two or more lens units
Implementation Method 3
The intermediate group includes a first focus unit F1 and a second focus unit F2 that move during focusing from infinity to a close distance
Data Source
AI summary
A zoom lens includes a plurality of lens units. The plurality of lens units consist of, in order from an object side to an image side, a first lens unit having negative refractive power, an intermediate group having positive refractive power, the intermediate group including two or more lens units, an aperture stop, and a rear group including at least one lens unit. A distance between adjacent lens units changes during zooming from a wide-angle end to a telephoto end. The intermediate group includes a first focus unit and a second focus unit that move during focusing from infinity to a close distance.