Single Chip LIDAR with Discrete Beam Steering by Digital Micromirror Device

Multi-beam and single-chip LIDAR with discrete beam steering by digital micromirror device

“…The number of scanning angles can be increased by employing a larger DMD micromirror pitch and/or a shorter wavelength. 13 The limitations of two commercially available DMDs under ideal conditions for certain wavelengths of light are shown in Table 1. In the Table it Currently, angular spacing among multiple laser diodes is limited by size of housing of laser diode modules, and/or optics to collimate laser beam, thus it is not possible to accommodate 18 lasers.…”

“…11,12 As previously demonstrated by our group, beam steering by Digital Micromirror Device (DMD) with a short pulsed laser is not only possible, but can be implemented in scanning LIDAR systems. 13 This beam steering technique has a high beam steering efficiency (close to 100% in theory), a larger beam size (~same as DMD area), a wide field of view (48 degrees), and a high scan rate (tens of KHz) while minimizing the number of moving parts. The limitation of the approach, however, is maximum number of scanning point is limited by number of diffraction orders available, and is about 5 to 9 points for wavelength range of 0.5 to 1 m, with commercially available DMD.…”

Angular and Spatial Light Modulation by Single Digital Micromirror Device for Multi-Image Output and Nearly-Doubled Étendue

“…Equation 1, the diffraction grating equation, determines the output diffraction order angles for a DMD with square micromirrors which rotate along their respective corner-tocorner axes, where inc θ is the source input angle of incidence, n θ is the diffraction-orderspecific output angle, n is the diffraction order number, λ is the wavelength, and p is corner-to-corner pixel pitch. The 2 is due to the 2 p pitch between neighboring pixels' axes of rotation in the arrayed structure [16] . Put more simply, the angular extent of the discrete output diffraction orders is limited to the reflected angular extent of the micromirrors (e.g., 48° for a ± 12° micromirror).…”

“…Put more simply, the angular extent of the discrete output diffraction orders is limited to the reflected angular extent of the micromirrors (e.g., 48° for a ± 12° micromirror). For instance, for the DLP3000 DMD with a 24° full angular throw ( ± 12°), a 10.8 µm corner-to-corner pixel pitch, 905 nm illumination, and a 30° illumination angle of incidence, the DMD can sequentially steer across 5 diffraction orders (e.g., −2, −1, 0, 1, 2) by manipulating the diffraction efficiencies of multiple orders through controlling the programmable blaze angle [16].…”

“…The 2D arrayed output system was created using three green LEDs (Kingbright, WP154A4SEJ3VBDZGW/CA, 5 mm RGB, only green channel used), where each LED pulse has a duration of one clock cycle (62.5 ns) of the driving Arduino Uno. (The Arduino Uno microcontroller drives the DMD-based beam steering, see [16] for more details.) The DMD (DLP3000, Texas Instruments) was operated at 4 kHz and sequentially synchronized to LEDs pulsing at 2 kHz to accommodate the black pattern refreshes between multi-perspective patterns.…”