Beam Scanning Display Mirror Distortion Correction
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Solution Overview
Problem
Existing irradiation display apparatuses face challenges in measuring irradiation distance and correcting image distortion, especially on uneven or curved surfaces, due to the need for a large space for light detection and the inability to account for surface shape variations.
Innovation Solution
A beam scanning type display apparatus with a light source, a reflection angle variable mirror, and at least two light detectors that calculate drive correction values for the mirror based on detected light amounts and mirror inclination to perform image correction, allowing for more space-efficient distance measurement and distortion correction on various surface shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a two-dimensional position sensitive light detector (PSD) is used to measure irradiation distance by triangulation method, then the irradiation distance measurement is achieved, but the device size becomes large due to the space required for guiding reflected light to the detector
Solution Approach 1:
The patent combines the distance measurement function and image projection function into a single compact device. The light detector is integrated into the projection device body, and the reflected light from the irradiation screen is directly detected without requiring separate light guiding paths, thereby reducing device size while maintaining measurement capability
Solution Approach 2:
The light detector serves dual purposes: it detects the reflected light for distance measurement and also contributes to the overall projection system functionality. The same optical path is used for both image projection and distance measurement, making the device more compact and multi-functional
2Ease of operation
If laser light is radiated obliquely onto an irradiation screen, then the beam scanning function is achieved, but image distortion such as trapezoidal distortion occurs
Solution Approach 1:
The patent uses light detectors to detect the reflected light from the irradiation screen and calculates the actual irradiation distance and screen inclination. This information is fed back to the control unit, which then adjusts the mirror inclination angles to correct the image distortion, ensuring accurate image projection even on inclined or uneven surfaces
Solution Approach 2:
The control unit dynamically changes the mirror inclination angles based on the detected screen position and inclination. By adjusting these parameters in real-time, the system compensates for the trapezoidal distortion caused by oblique irradiation and maintains image quality across different projection conditions
3Adaptability or versatility
If the irradiation surface is a curved surface or has unevenness, then the display can adapt to various surfaces, but distortion correction becomes difficult because the projected image expands and contracts
Solution Approach 1:
The patent divides the irradiation surface into multiple measurement points using multiple light detectors positioned at different locations. Each detector measures the local inclination and distance of its corresponding region, allowing the system to handle complex curved or uneven surfaces by processing each segment independently and correcting distortions locally
Solution Approach 2:
The patent transitions from single-point distance measurement to multi-point three-dimensional surface mapping. By using multiple light detectors arranged in specific positions, the system captures spatial information in multiple dimensions, enabling accurate distortion correction across curved and uneven surfaces through comprehensive surface characterization
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 high-quality image display with reduced distortion by detecting and correcting for irradiation surface irregularities, including color shading and uneven shapes, without the need for extensive space for light detection.
Implementation Method 1
at least two light detectors which detect a light amount of screen reflection light of the beam light
Data Source
AI summary
A beam scanning type display apparatus includes a reflection angle variable mirror that scans a beam light, at least two light detectors disposed at a predetermined distance in a beam scanning direction of the mirror that detects a light amount of screen reflection light, a distortion correction calculation unit that obtains a drive correction value of the mirror by calculating an irradiation distance and a screen inclination, from a light amount of a reflection light detected by the light detectors at two different scanning timings and an inclination angle of the mirror at this time, and a mirror driving unit that controls an inclination angle of the mirror by the drive correction value. A drive correction value of the mirror driving unit is obtained at a plurality of timings of a scanning period of beam light, and beam light is scanned at the corrected inclination angle of the mirror.