Technical Details of Hermetic Packages for LiDAR Sensors
LiDAR sensors must deliver continuous high performance in challenging automotive environments. Sensitive optical LiDAR components need reliable packages for long-term protection against harmful elements. These packages must simultaneously offer precise optical interfaces and exceptional thermal dissipation properties to achieve stable laser wavelengths.
Vacuum Tightness
- Our hermetic packaging technology allows the implementation of tailored and controlled internal pressure environments (typically < 1x10-8 mBar*l/s).
- Hermeticity enables the required internal pressure to be maintained over an extremely long time period.
Reliability
Corrosion resistance
- Humidity test: 85⁰C, 85% RH, 1000 hours.
- Salt spray test: 35⁰C, 0.5 - 3% salt concentration, 24 hours.
Thermal stability
- Thermal shock: -65 to 150⁰C, 15 cycles.
- Soldering compatibility: 260⁰C for 5 minutes.
Plating stability
- Bake test: 425⁰C for 15 minutes (no plating discoloration or blistering).
- Solderability of leads: wet homogenously with stains / bare spots <5%.
- Mandrel test: leads to be coiled at 1mm diameter, 2-6 coils with no plating blistering or peeling.
Mechanical stability
- Leads twisting and bending with load: 56g for pin diameter Ø0.25 ~ 0.29mm, 85g for pin diameter Ø0.3 ~ 0.5mm.
- Tensile test: 10N for pin diameter 0.20-0.29mm, 23N for pin diameter 0.30-0.50mm.
Thermal Conductivity
- Optimized thermal material (CuW, OFHC) choices available: copper thermal conductivity = 385 W/m-k.
- TEC (thermoelectric cooler) designs and ceramic multilayer substrates are also available.
Optical
- Windows, lenses and coatings available for improved optical transmission and reduced reflection.
- High transmission glass in 905 - 1550nm range.
- Glass filters / coatings.
- Angled window caps also available.
Optical Emission Direction
- Vertical emission for VCSEL, as with TO packages.
- Horizontal emission for edge-emitting laser diodes.
Mechanical
Through Hole and SMD Technology
- THT: Through Hole Technology – particularly reliable for environments with mechanical vibration / shock.
- SMD: Surface Mount Technology – particularly reliable for packages with lower mass.
Sealing methods
- Projection welding – fast, economical, low heat dissipation to the chip.
- Seam sealing – rectangular package, seal in array form.
- Eutectic soldering such as AuSn – <350⁰C.
- Laser welding – high precision.
Electrical
Insulation Resistance
- Feedthrough insulation > 1x10^10 ohm at 50% RH, 100V.
Kristina Gruber
Product/Sales Manager