All about automotive lidar

Laser eye safety, standards, and failure modes

• Thread opens with detailed concerns about 905/940 nm vs 1550 nm lidars, cataract/retinal damage thresholds, and worst‑case “stuck beam” failures (stuck mirror or phased array).
• Commenters worry about:
  • Lack of published beam‑failure shutoff latency (claims of >50 ms).
  • No standard for multi‑source exposure (many cars at an intersection).
  • Proprietary lidar designs and difficulty finding independent certifications.
• Others push back:
  • Automotive lidars are certified as Class 1; similar low‑power lasers (e.g., barcode scanners) have massive exposure history without obvious epidemics.
  • IEC 60825 is a standard, not a regulation, and explicitly requires evaluation under foreseeable single‑point failures like scan failure.
  • For retina‑focused wavelengths, beams from different directions generally hit different retinal spots, so “20x exposure” is said to be ill‑founded; corneal heating at 1550 nm is acknowledged as additive.
• Historical analogies (lead, tobacco, PFAS, asbestos) are used to argue that “it’s been fine so far” is not sufficient.

Evidence, anecdotes, and perceived risk

• Reports of lidar burning pixels on phone and DSLR cameras (including Volvo EX90 cases) are treated by some as a strong red flag; others note camera sensors are more fragile than eyes.
• Concern that depot staff and cleaners around fleets could be harmed without easy attribution; skeptics point out injuries would become hard to hide at scale.
• One rider describes being physically “whacked” by an exposed spinning bumper lidar; others explain design trade‑offs (field of view, optical quality, cooling).
• Several participants look for or propose IR‑blocking sunglasses / coatings; existing laser safety glasses are seen as overkill or visually obtrusive.

Lidar architectures, interference, and engineering trade‑offs

• Technical discussion covers:
  • Energy‑per‑pulse vs power and the push to very short pulses (sub‑10 ns) using GaNFETs, plus need for very fast ADCs/TDCs.
  • Severe EMI and self‑crosstalk when high‑current laser drivers sit inches from nanoamp‑level detectors; mitigations include geometry, noise cancellation, modulation, and timing strategies.
  • Range vs pulse‑repetition trade‑offs and temporal aliasing; limited use of code sequences/jitter given eye‑safety energy budgets.
  • Flash lidar for short‑range, and FMCW systems; clarification that FMCW doesn’t strictly require fiber lasers.
  • Distinction between discrete macroscopic emitter arrays (no beamforming) and true phased arrays (software‑controlled beamforming).

Inter‑lidar interference in dense traffic

• Some argue overlapping scanners at intersections could cumulatively exceed safe exposure.
• Others counter:
  • 905/940 nm beams will land on different retinal spots.
  • 1550 nm systems could, in principle, accumulate corneal heating, but are designed with divergence and scanning patterns that make precise overlap unlikely.
  • Random jitter and coded emissions (analogous to GPS) are used to reduce sensor interference; for pulsed automotive lidars, modulation options are limited by power circuitry.

Lidar vs camera‑only autonomy (Waymo vs Tesla)

• One camp: lidar adds indispensable, safety‑critical information and is key to current Level 4 systems; camera‑only systems remain behind in reliability and can’t yet run driverless.
• Opposing camp: lidar is fundamentally flawed or at least not worth its complexity, cost, and safety risk; camera‑only (Tesla‑style) systems are improving rapidly and may make lidar obsolete.
• Debates hinge on:
  • Current safety records (with disagreements over how to interpret small fleets and supervised vs driverless operation).
  • Scalability: geofenced, map‑heavy lidar stacks vs generalist camera systems.
  • Diminishing returns: several Tesla FSD users report excellent performance and doubt lidar would improve it enough to justify cost.
  • Others stress that anecdotal success doesn’t capture rare catastrophic failures and that only large‑scale post‑deployment stats will settle the question.
• Volvo’s decision to drop lidar from future models is cited by some as evidence against lidar’s long‑term role; others note existing production uses (e.g., Audi/Scala) and even museum pieces as part of lidar’s technological arc.