Q Academy

Charging the Crucible

Charging the crucible is an important step in the process of AR coating. This is where the consumable evaporant materials which comprise the coating are loaded into the AR system’s crucible. It is important to use high quality materials supplied by your coating vendor so that material consistency can be counted on. This will lead to consistent machine deposition performance and high quality coatings.

Equipment and Materials

  • Clean crucible
  • Tweezers
  • Vacuum cleaning system
  • Consumable evaporant materials (consumables)
  • Clean, dry, lint-free cloth or swab
  • Scotch Brite pads

Charging Instructions

  1. Under normal operation, the crucible will be loaded and unloaded from the charging screen.
  2. Always use a freshly cleaned crucible for each run.
  3. Clean crucibles ensure a minimum of contamination, better coating adhesion and lower pump times.
Cleaning the Crucible
  1. Unload used tablets contained in the crucible with tweezers.
  2. Remove all oxidized (discolored) portions of the granulate compounds using tweezers.
  3. Vacuum all loose dust and/or coating overspray from the crucible.
  4. Clean liners using Scotch Brite pads acetone.

NOTE: In some systems, debris left on bottom of crucible causes insufficient contact with crucible carrier and can bring about crucible overheating.

Refill All Crucible Holes
  1. Fill appropriate pocket with new adhesion material (Quantum EV-00004 or EV-00012) granules until the granules are flush with the top of the crucible; do not mound granules.
  2. Fill appropriate pocket with new high index material (Quantum EV-00023 or EV-00026) tablet using tweezers; ensure tablet is centered and level.
  3. Fill appropriate pockets with new low index material (Quantum EV-00003) granules until the granules are flush with the top of the crucible.
  4. Fill appropriate pocket with new overcoat material (Quantum EV-00016) granules.
  5. Fill appropriate pocket or boat with new copper super hydrophobic (Quantum EV-00038, EV-00042, or EV-00051) cup and lid.
    1. Make sure lids, liners, and pockets are clean and free of any carbon deposits or debris.
    2. Use acetone and Scotch Brite to clean when necessary.
  6. Being careful to not tilt the crucible, wipe any debris from the bottom using a dry cloth or swab.
  7. When loading into the chamber, align the crucible so that the steel pin on the front of the crucible carrier stand fits securely into the slot provided on the crucible.
Warm-up Cycle
  1. Open chamber door and load a sample plano lens into clean sector/collet.
  2. Check rotation of carousel for loose lenses.
  3. Load charged crucible and shutter.
  4. Actuate shutter for proper travel and speed.
  5. Change the crystal.
    1. This is vital for EVERY run as the crystal controls the deposition process.
  6. Double check to assure that all the above are correct, then push start.
  7. Observe all monitors during the run.
    1. Note run-times, pressures, and temperatures during warm-up.
  8. Periodically observe electron beam aim.
    1. Beam should be centered in substance.
    2. Caution: use the welder’s glass for eye protection.
  9. After the cycle is complete, the machine will automatically vent and open the door.
  10. After door is opened, remove the sector from the machine and place in the flow booth.
  11. Clean electron beam gun with Scotch Brite.
  12. Vacuum inside chamber.

CAUTION: Wear proper eye protection when observing machine operation.

Chemicals used to make the AR

EV-00004 / EV-00012

Adhesion (granular) – the primary material between the hardcoat and the AR stack; it is the first line of defense in any good AR process. Proper adhesion of the AR to the lens increases AR quality, durability and the ability to warranty the job. Without this layer, the lab will see immediate returns and failures.

EV-00003

Low Index (granular) – the “quartz material” that interacts with light to create the anti-reflective properties. It also aids in the overall abrasion resistance (hardness), which is increased by the aid of the ion source during deposition. Improper deposition of this material will result in inconsistent durability (too hard or too soft) in the coating.

EV-00026 / EV-00023

High Index (pill) – the combination of this material with the low index is instrumental in creating the “green” color we are so used to seeing on the AR lens. Improper deposition of this material can create the wrong color, poor repeatability and overall quality issues for overall cleanability of the lens, poor protection from dust and oils, and patient dissatisfaction.

EV-00038 / EV-00042 / EV-00051

Super Hydrophobic (cup) – the layer responsible for overall cleanability of the lens. Improper deposition of this material will result in poor protection from dust and oils and patient dissatisfaction.

EV-00016

Super Hydrophobic Overcoat (granular) – the final layer, which temporarily covers the super hydrophobic layer to allow edging without lenses slippage. Improper deposition of this material may result in breakage due to slippage in the edging process.