Positionable LED mounts

by Krista Disano

These instructions may be used to create a small LED mount (using a 16mm cage plate to mount the LED) or a large LED mount (using a 30mm cage plate to mount the LED).  One advantage of using the larger LED system is the dispersion of heat from the LED onto the cage plate. However, if you plan on assembling a larger LED system, the increase in weight from a larger cage plate will lead to less stability when mounted onto a cage rod. The system may not stay in place at certain angles. Make sure you check this before assembling!  The excess heat emitted by the LED can also be resolved by mounting a heat sink on the back of the cage plate. I would recommend that both systems use heat sinks. Otherwise, the LED’s may burn out with prolonged use. 

MATERIALS:
  • Cage plates (depending on the preferred size of the system; you'll need the corresponding retaining rings from ThorLabs)
    • For a small system:(1) Small cage plate (16-mm; ThorLabs #SPO1) and (1) adapter plate (ThorLabs #SP05)
    • For a large system: (2) Large cage plate (30 mm; ThorLabs #CPO1)
  • Cage assembly rods:
    • For a small system: (4) 1-inch mini cage assembly rods (ThorLabs #SR1)
    • For a larger system: (4) 1-inch cage assembly rods (ThorLabs #ER1)
  • (1) Rod end swivel connector (#C2A) Note: order additional cage rods if you want the arm holding the LED to be longer
  • Heat sink (ordered from Mouser electronics)
    • For a small system: (1)  (it's either 774-APF19-19-13CBA01 APF19-19-13CB/A01 Heatsinks 19x19x13mm Heat Sink 0.13mm 4000V/mi or it's 774-BDN125CBA01 BDN125CBA01 Heatsinks IERC Heat Sink 1.21x1.21x0.555).
    • For a large system: (1) 774-BDN125CBA01 IERC Heat Sink from Mouser Electronics
  • Collimating lens (you'll want a spanning wrench to put in the lens,SPW603 for small cage system, SPW602 for large cage system):
    • For a small system: (1) 10.5mm focal length, 12mm diameter aspheric condenser lens (ThorLabs #ACL1210-A)
    • For a large system: (1) 20mm focal length, 25mm diameter aspheric condenser lens (ThorLabs #ACL2520-A)
  • LED of the desired wavelength, for example:
    • Luxeon Rebel Star LEDs
    • Cree Blue XLAMP 485nm LED, XREBLU-L1-R250- 00K01CT-ND, order from DigiKey
  • (1) BNC test lead (ordered from L-COM #BC55)
INSTRUCTIONS:

The following assembly is for a small LED illumination system (Notes will be made if you need to modify a step for a large LED system).

1. Take the aspheric lens and mount it into the cage adaptor plate (#sp05)

2. Add the 4 mini cage assembly rods (#SR1) into the holes closest to the lens. If you are making a larger system, the rods (#ER1) will be on the outer 4 holes.

3a
. Use a cage plate ((#SP01) 16mm for mounting the LED in a small system and (#CP01) 30mm for a large system) to add an LED and BNC lead.

3b
. For the small system, the LED must be cut down using the dremel. Beware of the connections when you are trimming the LED.  If you are using a large system you will not need to cut down the LED. Solder the BNC lead onto the LED after it has been trimmed. The wire coming from the center of the BNC lead is positive, while the outer cable is negative. Attach the LED to the cage plate with arctic silver. 

4
. Add on a heat sink to the opposite side of the cage plate with the LED. Be careful that the heat sink is not overlapping with the cage rod holes. Normally these heat sinks are stickers so they can be stuck right on; one could also use arctic silver thermal adhesive (be sure to get the thermal adhesive, not thermal paste).

5
. Attach the cage plate (with LED/heat sink) to the cage plate with the lens. The lens and LED must be exactly 1 lens focal length apart (10.5mm and 20mm for the small and large lenses above). 

6
. Finally, attach a swivel rod to the system. This allows the system to be attached to the intrinsic imaging system and move around. You will adjust the length of this arm and the point of attachment to suite your own needs. 

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