Structured-light intraoral scanners require the projection of precise light patterns onto the tooth surface. DLP (Digital Light Processing) technology is one of the core solutions for generating these patterns.
Working Principle of DLP
The heart of DLP is the DMD (Digital Micromirror Device) chip developed by Texas Instruments. The surface of a DMD contains hundreds of thousands to millions of micron-scale aluminum micromirrors, each corresponding to one pixel and capable of independently tilting ±10–12 degrees. In the "on" state a micromirror reflects light into the projection lens; in the "off" state it reflects light into a light absorber. By rapidly switching the micromirror states in combination with the light source, any black-and-white or grayscale pattern can be projected.
Application in Intraoral Scanners
Devices such as the 3Shape TRIOS series use a DMD to project checkerboard and fringe patterns.
The DMD can switch patterns at high speed (thousands of frames per second), supporting multi-step phase-shifting profilometry-rapid sequential projection of phase-shifted fringes that improves phase-calculation accuracy.
Combined with RGB LEDs or a color wheel, the DMD can project color patterns or time-sequentially project different colors.
Advantages of the DLP Approach
Flexible programmable patterns: Any fringe, Gray-code, checkerboard, or random speckle pattern can be generated by software, facilitating algorithm iteration and upgrades.
High contrast: DMD on/off contrast is high, producing sharp pattern edges.
High speed: Micromirror switching occurs at the microsecond level, supporting high-speed 3D acquisition.
Wide spectral range: Compatible with visible-light, near-infrared, and other light sources.
Challenges of the DLP Approach
Volume: The DMD chip, illumination optics, and projection lens require space; miniaturizing the scanning tip remains an engineering challenge.
Heat dissipation: Heat from the DMD and light source is concentrated and demands precise thermal management.
Cost: DMD chips and driving circuitry are relatively expensive.
Sterilization tolerance: The entire projection module must withstand high-temperature, high-pressure autoclave conditions of the scanning tip (or be designed so that it does not enter the sterilization zone).
Alternative Projection Technologies
LCoS (Liquid Crystal on Silicon): Similar to DLP but uses reflective liquid crystals; contrast and light efficiency have different trade-offs.
MEMS laser scanning: A micro-electromechanical galvanometer scans a laser beam; no DMD is required, resulting in a smaller volume, but field of view and speed are limited.
Laser speckle projection: A fixed random-speckle pattern is generated by a diffractive optical element (DOE). The structure is simple, but the pattern cannot be changed.
The maturity and flexibility of DLP technology make it the preferred projection solution for high-end structured-light intraoral scanners.
At Aident Technology, the AI-30 intraoral scanner series employs advanced structured-light projection optimized for clinical performance. With ≥30 frames per second, ≤10 μm full-arch accuracy, powder-free true-color scanning, intelligent anti-fog heating, and an ultra-lightweight 156–198 g design, the AI-30 delivers reliable digital impressions for modern chairside and laboratory workflows.
Explore our solutions:
Contact Aident for OEM/ODM collaboration, wholesale pricing, or a live demonstration and experience how precise structured-light projection contributes to accurate digital dentistry.
