Zoom Projection Lens Autofocus Across Variable Zoom Ratios
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Solution Overview
Problem
Existing autofocus capabilities in projection devices are limited to lenses with fixed throw ratios and cannot be applied to projection devices with adjustable zoom ratios, such as zoom projection lenses.
Innovation Solution
A projection device and method that includes a zoom projection lens, a sensor, a focus adjustment module, a zoom-ratio adjustment module, and a detection module, utilizing an autofocus transfer function to calculate focus adjustment parameters based on projection distance and detection values, enabling automatic focusing with adjustable zoom ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed throw ratio lens is used with existing autofocus methods, then automatic focusing can be implemented, but the device cannot support adjustable zoom ratios
Solution Approach 1:
The patent implements dynamic focus adjustment by making the focus position variable according to the zoom ratio. The focus adjustment module dynamically changes the focus position based on real-time zoom ratio detection, allowing the system to adapt focus settings as the zoom ratio changes, thereby maintaining autofocus capability across all zoom levels.
Solution Approach 2:
The patent employs a feedback mechanism where the detection module continuously monitors the zoom ratio, and this information is fed back to the control unit. The control unit then calculates the appropriate focus adjustment parameter based on this feedback and adjusts the focus accordingly, creating a closed-loop system that maintains accurate focus despite zoom ratio changes.
2Measurement precision
If multiple focus adjustment parameters are stored for different distances, then focus accuracy can be improved, but device complexity increases due to lookup tables
Solution Approach 1:
The patent changes the parameter organization from static distance-based lookup tables to dynamic calculations based on zoom ratio and projection distance. Instead of storing focus parameters indexed by distance, the system calculates focus parameters using the detected zoom ratio and projection distance, reducing memory requirements and simplifying the data structure while maintaining focus accuracy.
Solution Approach 2:
The patent replaces the mechanical lookup table approach with a computational method. Instead of retrieving pre-stored focus parameters from a complex data structure, the system uses the control unit to calculate focus parameters in real-time based on simple inputs (zoom ratio and projection distance), thereby reducing device complexity.
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
Enables automatic focusing capability in projection devices with zoom projection lenses across various zoom ratios, ensuring clear projection images by adjusting the imaging focal length based on detected values and distances.
Implementation Method 1
The sensor is configured to sense a projection distance between the projection device and the projection surface
Implementation Method 2
The zoom projection lens is disposed on a transmission path of the image beam, and is configured to project the image beam generated by the projection module to a projection surface to generate a projection image
Implementation Method 3
The focus adjustment module is connected to the zoom projection lens and is configured to rotate the zoom projection lens to adjust an imaging focal length of the zoom projection lens
Implementation Method 4
The detection module is connected to the zoom projection lens, and is configured to generate a corresponding detection value according to a displacement variation of the lens group
Data Source
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AI summary
A projection device and a projection correction method are provided. The projection device includes a projection module, a zoom projection lens, a sensor, a focus adjustment module, a zoom-ratio adjustment module, a detection module and a control unit. The zoom-ratio adjustment module adjusts a position of a lens group in the zoom projection lens to adjust a zoom ratio of a projection image generated by the zoom projection lens projecting an image beam generated by the projection module. The control unit uses an autofocus transfer function to calculate a focus adjustment parameter based on a corresponding detection value generated by the detection module detecting displacement of the lens group and a projection distance sensed by the sensor, and controls the focus adjustment module according to the focus adjustment parameter to adjust an imaging focal length of the zoom projection lens.