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Old 12-03-2021, 02:11 PM
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Peter Ward
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Laser alignment of sensors

In another post a novel technique was mentioned about "squaring-on" of sensors within a camera housing.

There is a body of evidence that shows laser light can and does destroy sensors.

But don't take my word for it, a 30 second Google search should verify this.

Clearly the power of the lasers used are a factor plus whether any convex optic is being placed ahead of the sensor.
But it does beg the question, can I point a laser directly at a sensor and not damage it?

A unique property of laser light is that it can be focused to an exquisitely fine point. It is for this reason they can be applied to industrial cutting operations, as even though
the laser itself may only have a few watts of power, it's beam cam be concentrated far more than say the light from an incandescent light globe.

Lots of luck trying to cut anything with convex lens and a 100 watt globe...
But a 100 watt laser will cut most materials known to man.
Focused or not, laser light shining onto CMOS and CCD sensors that also have micro-lenses may have unintended consequences.

But back to the point at hand...is it a good idea to shine even a low power laser directly at a imaging sensor?
Lasers are classified in various classes, and after doing a bit of digging looks like sensors are immune to Class 1 devices.

Anything higher than that (e.g. Class 1M , Class 2 ,3 and 4) and you may well cause damage.

So Class 1 should be OK. But it also would be prudent to question the veracity of your laser's safety/classification label.....i.e a "cheapie" picked up on E-Bay may have bogus Classification labeling.

I'd also mention that when SBIG was located in Santa Barbara I was shown their sensor alignment rig.
They used simple optics with incandescent light source to "square-on" the sensor. At the time I asked why not a laser.

They just smiled...and reminded me that the sensor in the camera being tested at the time was worth $USD 5000.00 and wanted to keep it that way.

Last edited by Peter Ward; 12-03-2021 at 02:22 PM.
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Old 12-03-2021, 04:23 PM
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Yes, I have seen posts in a Sony full frame camera forum that a laser wrecked their Sony sensor. That sensor would be very similar to the QHY600m (I think it was either the 42.4mp A7R3 camera sensor or the 24mp one used in the Sony A7111).

So using lasers on expensive sensors sounds like a real no no. Especially these days with 90% plus QE. I am sure that level of sensitivity is a double edged sword also with its microlenses focusing light even more finely.

Gee, I thought simple Cosmic Ray hits degrade sensors over time.

CD definitely has some degradation over time with some sensors more susceptible than others.

Greg.

Last edited by gregbradley; 12-03-2021 at 04:43 PM.
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Old 12-03-2021, 04:27 PM
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thanks for posting. I had purchased a laser light for this purpose but hadnt got around to using it yet...will need to approach with more caution or not at all !
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