Optical Path Shifting Device with Voice Coil Actuator
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Solution Overview
Problem
Existing optical path shifting devices for image display devices, such as projectors, require reduction in size and thickness while maintaining necessary drive force, which is challenging due to their current design with vibration actuators using coils and permanent magnets.
Innovation Solution
The optical path shifting device incorporates a rectangular glass plate with a holding frame and a support part connected by shafts, utilizing an actuator positioned at a corner to apply torque, allowing for smaller size and lighter weight, with a magnetic sensor for feedback control and a thermistor for temperature management, enabling efficient pixel shifting for resolution enhancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vibration actuator with coil and permanent magnet is used to cause the glass plate to swing, then the optical path can be shifted, but the device size and thickness increase
Solution Approach 1:
The patent extracts the permanent magnet from the traditional vibration actuator configuration and replaces it with a voice coil motor. This removes the bulky permanent magnet component while retaining the essential oscillation function, thereby reducing device size and thickness while maintaining optical path shifting capability
Solution Approach 2:
The patent replaces the mechanical vibration actuator system (with permanent magnets and coils) with an electromagnetic voice coil motor system. This substitution eliminates the need for physical oscillation of heavy components and achieves the same optical path shifting effect with a more compact configuration
2Measurement precision
If the glass plate is made to swing with large amplitude, then resolution enhancement is achieved, but the drive force requirement increases
Solution Approach 1:
The patent utilizes mechanical vibration of the glass plate at specific frequencies to achieve optical path shifting. By employing resonant vibration, the system can achieve larger oscillation amplitudes with minimal drive force, enabling resolution enhancement without requiring excessive power
Solution Approach 2:
The patent changes the operational parameters by using a voice coil motor that can precisely control the oscillation amplitude and frequency of the glass plate. This allows optimization of the drive parameters to achieve the necessary swing amplitude for resolution enhancement while minimizing the required drive force through efficient electromagnetic actuation
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 enables a smaller and lighter optical path shifting device that effectively enhances image resolution by shifting the optical path with a constant amplitude, increasing apparent pixels and achieving a smaller size and lower resonance frequency.
Implementation Method 1
Each vibration actuator applies an alternating voltage to the pair of coils, thus causes a magnetic field generated by the coils to move the permanent magnet, and causes the moving part to swing
Implementation Method 2
The optical path shifting device can refract the image light incident on the glass plate and shift the optical path
Data Source
AI summary
An optical path shifting device includes: a holding frame holding a rectangular glass plate; a support part supporting the holding frame in a swingable state; and an actuator causing the holding frame to swing. The holding frame has a first shaft part at a position opposed to a first corner part of the glass plate, and a second shaft part at a position opposed to a second corner part situated in a diagonal direction from the first corner part. The holding frame is connected to the support part by the first and the second shaft parts. The actuator is arranged at a position opposed to a third corner part and has a permanent magnet and a coil opposed to each other. A first opposing surface of the permanent magnet and a second opposing surface of the coil are arranged in a direction intersecting a surface of the glass plate.