Laser Projection Display Timing Adjustment for Intensity Detection
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Solution Overview
Problem
Existing laser projection display systems face challenges in maintaining image brightness while preventing light emissions for intensity detection from interfering with the displayed image, often requiring costly shielding and reducing luminance by increasing scanning angles.
Innovation Solution
A laser projection display system that includes a timing adjustment unit to separate display and intensity detection periods, and a scan mirror driving unit with distinct scanning directions and deflection angles, allowing for blocked light emission during intensity detection without decreasing image brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light emissions for intensity detection are executed in the non-image display region, then laser light intensity can be adjusted, but the display image becomes close in location to the light emissions requiring precise shielding that increases cost
Solution Approach 1:
The patent changes the spatial arrangement by executing intensity detection light emissions in the vertical flyback period when the scan mirror is at the upper end of its scanning range, rather than in the horizontal non-image display region. This temporal and spatial separation in another dimension eliminates the need for precise shielding structures while maintaining detection accuracy.
Solution Approach 2:
The patent performs intensity detection during the vertical flyback period before the main image display begins. By completing the detection action preliminarily during the flyback time, the system avoids interference with the displayed image and eliminates the need for complex shielding during the image display period.
2Object-affected harmful factors
If the scanning angle is increased to keep the display image away from light emissions for intensity detection, then light interference is avoided, but the luminance of the display screen decreases
Solution Approach 1:
The patent utilizes the periodic vertical flyback motion of the scan mirror to execute intensity detection only during brief intervals when the mirror is at the upper end of its scanning range. This periodic action during flyback periods allows detection without increasing the scanning angle, thereby maintaining display screen luminance while avoiding light interference with the image.
3Illumination intensity
If a light blocking object is incorporated to prevent light emissions for intensity detection from being projected in the screen, then image brightness is maintained, but the device complexity and cost increase
Solution Approach 1:
The patent extracts the intensity detection function from the image display region and relocates it to the vertical flyback period. By separating the detection function in time and space, the system eliminates the need for light blocking objects while maintaining both image brightness and detection capability.
Solution Approach 2:
The patent utilizes the existing vertical flyback motion of the scan mirror for its primary scanning function to simultaneously enable intensity detection. The scan mirror's own motion during flyback provides the temporal window for detection without requiring additional light blocking structures or complex shielding mechanisms.
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
Effectively prevents light emissions for intensity detection from interfering with the displayed image while maintaining image brightness by varying deflection angles and scanning speeds, ensuring high luminance and precise positioning.
Implementation Method 1
a laser light source that generates laser light of multiple colors
Implementation Method 2
a scanning unit that projects an image by scanning with laser light generated by the laser light source in accordance with synchronization signals for image signals
Data Source
AI summary
A laser projection display system that executes, by swinging a scan mirror, scanning with laser light of multiple colors in accordance with image signals, thereby displaying an image in accordance with the image signals, includes: a timing adjustment unit that divides temporally a display period during which the image signals are displayed and a light emission period for intensity detection to detect the intensity of the laser light; a laser light source that generates the laser light of the multiple colors; a laser light source driving unit that drives the laser light source in synchronization with a signal from the timing adjustment unit; and a scan mirror driving unit including: a first scanning means that executes scanning in a first direction in response to synchronization signals according to the image signals, with laser light generated by the laser light source through the scan mirror.