Piezoelectric Drive Unit Positioning Without Tilting
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Solution Overview
Problem
Existing drive units using piezoelectric elements face challenges in accurately controlling the positional movement of optical components, leading to tilting issues when the movable object contacts a restricting member, which can degrade optical system performance and require larger restricting members or additional sensors, increasing cost and size.
Innovation Solution
A drive unit configuration that applies specific wave drive signals to the electromechanical transducer to control the movement of the supporting member, ensuring the movable object makes contact with the restricting member without tilting, using a first wave signal for contact and a second wave signal to maintain position, potentially with a third wave signal for correction, without the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the movable object makes contact with the restricting member to achieve positional control, then the positional accuracy is improved, but the movable object tilts which degrades optical system performance
Solution Approach 1:
The patent applies periodic vibration to the rod supporting the movable object, causing the movable object to repeatedly contact and separate from the restricting member. This periodic contact allows the movable object to be positioned accurately at the restricting member while the vibration prevents tilting by continuously adjusting the position, thereby resolving the contradiction between positional accuracy and tilting prevention
Solution Approach 2:
The patent utilizes mechanical vibration of the rod to achieve precise positioning. The vibration causes the movable object to oscillate between contacting and separating from the restricting member, allowing accurate positioning through controlled contact while preventing tilting through the dynamic vibration effect
2Object-affected harmful factors
If a larger restricting member is used to prevent tilting, then the tilting is reduced, but the device size increases
Solution Approach 1:
Instead of enlarging the restricting member, the patent uses periodic vibration to create repeated contact between the movable object and the restricting member. This dynamic approach prevents tilting through controlled oscillation rather than relying on the size of the restricting member, thereby preventing tilting without increasing device size
3Measurement precision
If additional sensors are added to detect position and prevent tilting, then the positional control accuracy is improved, but the device complexity and cost increase
Solution Approach 1:
The patent makes the rod serve dual functions: supporting the movable object and providing vibration for positioning. The restricting member serves as both a mechanical stop and a positioning reference through vibration-induced contact. This self-service approach eliminates the need for additional sensors while achieving accurate positional control
Solution Approach 2:
The patent implements multi-functionality where the rod既是支撑结构又是振动驱动装置，restricting member既是限位装置又是定位基准。Existing components perform multiple functions including support, vibration generation, and positioning reference, eliminating the need for separate sensors and reducing system 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
This approach effectively prevents tilting of the movable object during contact with the restricting member, allowing precise positional control without additional sensors, reducing system size and cost, and maintaining optical axis alignment.
Implementation Method 1
A piezoelectric element 4 comprises multiple piezoelectric plates stacked. One end 4a thereof in the expansion/contraction direction is secured to a base 1, and the other end 4b thereof is secured to the first end 5a of a rod (supporting member) 5.
Implementation Method 2
Because the rod 5 is flexible, the rod 5 vibrates with a displacement having a sawtooth shape in the direction of its length in response to the displacement of the piezoelectric element 4
Implementation Method 3
The spring force of the hold-down spring 10c of the movable object 10 (the frictional connection force applied from the movable object 10 to the rod 5) is adjusted so that the movable object 10 moves together with the rod 5 when the rod 5 moves slowly
Data Source
AI summary
A drive unit being characterized in that a movable object can be prevented from being tilted when the movable object is stopped using a restricting member. The drive unit comprises a piezoelectric element; a rod provided at an end of the piezoelectric element; a movable object, which is frictionally engaged with the rod and the movable range of which is restricted using the restricting members; and drive pulse generating means for applying drive signals to the piezoelectric element, wherein the drive pulse generating means apply a first wave drive signal for vibrating the rod so that the movable object moves toward the restricting member when the movable object is moved to a position where the movable object is close to the restricting member, and temporarily apply a second wave drive signal for vibrating the rod so that the movable object is moved in a direction of movement away from the restricting member after the movable object is made contact with the restricting member, and then stop the application of the drive signal.