Focus Adjustment Device with Movement Conversion for Portable Projectors
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Solution Overview
Problem
Miniaturized focus adjustment devices in portable image projection apparatuses are overly sensitive to user input, leading to unstable focus adjustments due to excessive movement of the projection lens unit.
Innovation Solution
A focus adjustment device with a rectilinearly movable member that converts linear movement into rotary movement, and further into linear movement of the projection lens unit, utilizing a first and second movement-converting member with guide slots and levers to control the lens unit's movement, along with an anti-shaking member to prevent shaking, achieving a distance attenuation ratio of less than 1.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the focus adjustment device is miniaturized to enhance portability, then the size of the projection apparatus is reduced, but the device becomes overly sensitive to user input causing excessive lens movement
Solution Approach 1:
The patent introduces a movement-converting member as an intermediary between the focus adjustment member and the projection lens unit. This converter transforms the direct linear movement into rotary movement, indirectly controlling the lens position and reducing excessive sensitivity while maintaining miniaturization
Solution Approach 2:
The patent changes the movement parameter relationship by introducing a conversion mechanism with a specific transmission ratio. The movement-converting member alters the movement magnitude parameter, making the lens movement distance smaller than the focus adjustment member movement distance, thereby stabilizing focus adjustment in miniaturized devices
2Length of moving object
If the focus adjustment device is miniaturized, then portability is enhanced, but the projection lens unit moves excessively in response to small user inputs
Solution Approach 1:
The movement-converting member serves as a mediator that decouples the direct relationship between user input and lens movement. By converting linear to rotary motion and providing mechanical advantage, it enables precise control of lens movement even in miniaturized configurations
Solution Approach 2:
The patent transforms the one-dimensional linear movement relationship into a two-dimensional conversion process involving both linear and rotary dimensions. This dimensional transformation allows for better control characteristics and reduced sensitivity in miniaturized devices
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 reduces the sensitivity of the focus adjustment mechanism, allowing stable focus adjustments in miniaturized image projection apparatuses by ensuring the projection lens unit moves a smaller distance in response to user input, thus maintaining focus accuracy.
Implementation Method 1
a first movement-converting member that converts a rectilinear movement of the focus adjustment member into a rotary movement of the rotational shaft
Implementation Method 2
a second movement-converting member that converts the rotary movement of the rotational shaft into a rectilinear movement of a projection lens unit
Data Source
AI summary
A focus adjustment device for adjusting a focus state of a projection lens unit in an image projection apparatus is provided. The focus adjustment device includes a focus adjustment member rectilinearly movable in a first direction; a rotational shaft; a first movement-converting member for converting a rectilinear movement of the focus adjustment member into a rotary movement of the rotational shaft; and a second movement-converting member for converting the rotary movement of the rotational shaft into in a rectilinear movement of the projection lens unit along a focusing direction.