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We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
On 5/22/19 11:49 AM, Winfield Hill wrote:
We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
That's a favourite technique of George's. Normally black anodized
threads aren't much of a problem--it takes many bounces off a black
surface for the light to get into your detector.
Of course most black anodize is coloured with organic dyes, which aren't
highly absorbing in the IR. You really want carbon for broadband loss.
How big was the leak, and what wavelength was it?
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
On Wednesday, 22 May 2019 22:44:22 UTC+1, tabb...@gmail.com wrote:
How about Kapton tape. Its already fairly dark in the visible and is
reported to have high emissivity in the far infra-red, so it might
be quite black in the near infra red also.
John
John Larkin wrote...
Even thin Kapton tape is black at thermal wavelengths.
I stick a bit onto shiny things to measure their
temperature with our Flir.
Do you think it should be taped over 1210 resistors
and SOT-23 transistors, for accurate readings? I'm
setting T-max for part surface readings of 120 deg C.
The circuit is working fine, but what about long-term
reliability? I have 2 watts dissipated in three near-
spaced 1210 resistors and three SOT-23 transistors.
Maybe could cover them with thermal tape or a heat-
spreader, plus a heatsink, but what's the temp then?
Even thin Kapton tape is black at thermal wavelengths.
I stick a bit onto shiny things to measure their
temperature with our Flir.
On Wednesday, May 22, 2019 at 3:15:48 PM UTC-4, Phil Hobbs wrote:
On 5/22/19 11:49 AM, Winfield Hill wrote:
We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
That's a favourite technique of George's. Normally black anodized
threads aren't much of a problem--it takes many bounces off a black
surface for the light to get into your detector.
Of course most black anodize is coloured with organic dyes, which aren't
highly absorbing in the IR. You really want carbon for broadband loss.
How big was the leak, and what wavelength was it?
Well I use a single layer of teflon tape to take out the backlash
in the fine threads of a thor lab lens tube. Not to block any light.
Not to you, but others. If you are blocking light to a silicon photodiode
then one thing to be aware of is that something 'black' in the visible,
may not be 'black' in the Near IR. (Which is one reason I like my
incandescent bulb... lotsa NIR photons.)
I haven't done any sort of systematic study, but I find that black
electrical tape makes a good light blocker at least down to 1 um.
On 22 May 2019 19:50:15 -0700, Winfield Hill
hill@rowland.harvard.edu> wrote:
John Larkin wrote...
Even thin Kapton tape is black at thermal wavelengths.
I stick a bit onto shiny things to measure their
temperature with our Flir.
Do you think it should be taped over 1210 resistors
and SOT-23 transistors, for accurate readings? I'm
setting T-max for part surface readings of 120 deg C.
The circuit is working fine, but what about long-term
reliability? I have 2 watts dissipated in three near-
spaced 1210 resistors and three SOT-23 transistors.
That doesn't sound bad. More copper helps a lot ...
A 1210 is fine at 1 watt if it's soldered to some
hunky copper pours.
Eyeballs aren't calibrated. Incandescent lamp butted into photodiodeOn 2019-05-22, George Herold <gherold@teachspin.com> wrote:
On Wednesday, May 22, 2019 at 3:15:48 PM UTC-4, Phil Hobbs wrote:
On 5/22/19 11:49 AM, Winfield Hill wrote:
We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
That's a favourite technique of George's. Normally black anodized
threads aren't much of a problem--it takes many bounces off a black
surface for the light to get into your detector.
Of course most black anodize is coloured with organic dyes, which aren't
highly absorbing in the IR. You really want carbon for broadband loss.
How big was the leak, and what wavelength was it?
Well I use a single layer of teflon tape to take out the backlash
in the fine threads of a thor lab lens tube. Not to block any light.
Not to you, but others. If you are blocking light to a silicon photodiode
then one thing to be aware of is that something 'black' in the visible,
may not be 'black' in the Near IR. (Which is one reason I like my
incandescent bulb... lotsa NIR photons.)
I haven't done any sort of systematic study, but I find that black
electrical tape makes a good light blocker at least down to 1 um.
electrical tape seems to cut the brightness of LEDs by an aparrent
factor of about 50 (mark-1 eyeball), metal tape is much more effective.
--
When I tried casting out nines I made a hash of it.
John Larkin wrote...
On 22 May 2019 19:50:15 -0700, Winfield Hill
hill@rowland.harvard.edu> wrote:
John Larkin wrote...
Even thin Kapton tape is black at thermal wavelengths.
I stick a bit onto shiny things to measure their
temperature with our Flir.
Do you think it should be taped over 1210 resistors
and SOT-23 transistors, for accurate readings? I'm
setting T-max for part surface readings of 120 deg C.
The circuit is working fine, but what about long-term
reliability? I have 2 watts dissipated in three near-
spaced 1210 resistors and three SOT-23 transistors.
That doesn't sound bad. More copper helps a lot ...
A 1210 is fine at 1 watt if it's soldered to some
hunky copper pours.
I have larger solder pads, but all six parts are
in close proximity. At 1kV, dissipating 2.1 watts
they get to 115C, at 2.6 watts, they show 144C.
That's at my 1.2kV goal, so add thermal tape and
heatsinks, or scale back a bit on the performance.
Plastic is pretty opaque in the mid-IR, so that's no big surprise.Phil Hobbs wrote...
On 5/22/19 11:49 AM, Winfield Hill wrote:
We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
That's a favourite technique of George's. Normally black anodized
threads aren't much of a problem--it takes many bounces off a black
surface for the light to get into your detector.
Of course most black anodize is coloured with organic dyes, which aren't
highly absorbing in the IR. You really want carbon for broadband loss.
How big was the leak, and what wavelength was it?
The teflon tape worked. 5032nm.
On 5/22/19 11:49 AM, Winfield Hill wrote:
We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
That's a favourite technique of George's. Normally black anodized
threads aren't much of a problem--it takes many bounces off a black
surface for the light to get into your detector.
Of course most black anodize is coloured with organic dyes, which aren't
highly absorbing in the IR. You really want carbon for broadband loss.
How big was the leak, and what wavelength was it?
On 5/23/19 2:50 PM, Winfield Hill wrote:
Phil Hobbs wrote...
On 5/22/19 11:49 AM, Winfield Hill wrote:
We used teflon tape to solve a problem with light
leakage, through loose threads, in a Thor Labs
2" optical tube. Comments or suggestions?
That's a favourite technique of George's. Normally black anodized
threads aren't much of a problem--it takes many bounces off a black
surface for the light to get into your detector.
Of course most black anodize is coloured with organic dyes, which aren't
highly absorbing in the IR. You really want carbon for broadband loss.
How big was the leak, and what wavelength was it?
The teflon tape worked. 5032nm.
Plastic is pretty opaque in the mid-IR, so that's no
big surprise. (Unless you meant 532 nm.)