Screen Drive Circuit for Oscillation-Free High-Speed Image Display
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Solution Overview
Problem
Conventional image display devices face challenges in smoothly stopping a screen that has moved at high speed without causing oscillations, particularly when displaying images with no depth, which affects the quality and visibility of virtual images in head-up displays.
Innovation Solution
The image display device incorporates a screen drive circuit that generates a drive signal by superimposing an acceleration/deceleration signal on a periodic signal, allowing the screen to reciprocate smoothly and stop accurately without oscillations, using a drive signal table to control the screen's movement and stop locations within a predetermined period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the screen moves at high speed to display images with depth, then the productivity of image display is improved, but the screen causes oscillations when stopping, worsening the stability of the displayed image
Solution Approach 1:
The drive signal table pre-calculates and stores optimal acceleration/deceleration profiles for the screen motor. Before the screen needs to stop, the control circuit retrieves the pre-computed deceleration signal from the drive signal table, allowing the screen to smoothly reduce speed and stop without oscillations, thus maintaining both high-speed performance and stopping stability
Solution Approach 2:
The control circuit dynamically changes the motor drive parameters by superimposing acceleration/deceleration signals from the drive signal table onto the periodic reciprocation signal. This parameter modulation allows the screen to transition smoothly between moving and stopping states, eliminating oscillations while maintaining high-speed display capability
2Adaptability or versatility
If the screen stops temporarily to display images with no depth, then the adaptability of the display device is improved, but the high-speed movement causes vibrations at stop locations, worsening the manufacturing precision of the screen positioning
Solution Approach 1:
The drive signal table pre-stores precise deceleration and positioning signals for various stop locations within the reciprocation range. When temporary stopping is required for displaying images with no depth, the control circuit retrieves the pre-calculated positioning signal that accounts for the screen's momentum and inertia, ensuring the screen stops accurately at the intended location without vibrations or oscillations
Solution Approach 2:
The control circuit uses the drive signal table to implement a feedback-based positioning system. The pre-computed acceleration/deceleration signals in the drive signal table are designed to counteract the screen's inertial effects, creating a self-correcting mechanism that ensures precise stopping at designated locations regardless of the high-speed reciprocation
Data Source
AI summary
An image display device includes a light source that emits a light beam, a screen, a scanning section that scans the screen with the light beam, an optical system, a drive section, and a screen drive circuit. The optical system generates a virtual image by using the light beam that has passed through the screen. The drive section moves the screen at least in parallel to a travel direction of the light beam. The screen drive circuit contains a drive signal table that stores an information group for use in generating a drive signal tailored to stop the screen at different stop locations over different stop periods. The screen drive circuit selects first information in the drive signal table which is associated with displaying of an image and supplies the drive section with a first drive signal generated from the first information.