Cheap Shenzhen Inspection Microscopes
Well I finally got round to playing with the inspection microscopes I picked up in Shenzhen. If I remember correctly the whole system came to about 80USD. The purchasing process is almost as exciting as the price, you need to buy the optics from one place, the CCD PCBs from another, and the CCD chassis from yet another place. Luckily they’re all in the same building which specializes in security equipment.
Here’s a selection of parts:
The CCD cameras and optics are all C-mount sometimes with C to CS (?) adapters. This is handy as most modern microscopes use C-mount and for older microscopes you can get eyepiece to C-mount adapters.
There are various CCD and CMOS imaging PCBs available. With a variety of network, composite, USB, and HDMI connections. Interesting composite seems to be favored for its low latency. I guess this is particularly important for inspection and rework. However it’s a little sad that the digital stuff isn’t faster these days…
I’ve been using the CCD, mostly because I’m kind of interested in CCD interfacing. It module uses a Sony CCD and CCD driver IC. It takes a 12v input. I hacked the connector off and used a lab PSU the supply it. Connecting the black to ground and other two wires to 12v. The module draws about 70mA. I used an old composite input monitor I had. I think I’ll buy some small monitors and a PC composite input acquisition card of some kind.
I purchased 2 sets of optics. One was fixed magnification, the other variable. First the fixed, the pads shown are for an SOIC8:
Then the variable, at max magnification. This is one of the pads from the device above:
As you can see the first image I took was pretty grey and washed out. This was due to poor lighting. Without illumination the images from the variable magnification lens were much poorer. However I’m very impressed by the working distance should be great for rework.
One issue with the variable magnification lens is that you have to keep refocusing as you change magnification. This isn’t an issue with the Wild Heerbrugg M8 which I’ve been using for rework lately, and it’s very handy to be able to zoom in and out. That however has a secondhand value for a 1000USD+.
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