detect cracks in solar cells

[9949633612]

hello,

    Iam using vision assistant 8.5,labview 8.6,my requirement is to find the cracks in solar cell,can any one suggest me a solution,iam sending the sample image

[another_novice · Accepted solution]

Your first task is to obtain an image with a difference in contrast between crack and 'good' surface. Did you mean to attach an image? There wasn't one.

Depending on the construction of your solar cells and the stage in the manufacturing process you're at, it might be worth exploring what IR lighting can do for you.

[Robert_Eastlund]

One successful technique for imaging cracks and other defects in solar cells is to use a SWIR camera (short wave infrared), see http://www.sensorsinc.com/photovoltaics.html.  Note: the SWIR technology is not inexpensive.

[AnalogKid2DigitalMan]

Darkfield illumination is often used to enchance surface defects or contamination, it may be of use in this situation.

I thought I read somewhere that applying a voltage to a solar cell makes it emit IR radiation, not sure if that is true, but it may make crack detection straightforward.

One thing to consider is how big the cell is versus how small a crack you need to detect. This will drive your camera lens selection and you may have to translate the cell under the lens if the cracks are small compared to the area you are imaging.

-AK2DM

[AnalogKid2DigitalMan]

Very illuminating, my memory served me correctly. And they always said I was the dimmest solar cell in the panel 🙂

http://www.physorg.com/news154013791.html

-AK2DM

[9949633612]

Thanq for ur suggestion sir,Iam sending the image.

[9949633612]

Than q for ur suggession,I cannot do Darkfield illumination forward bias cannot be given,as the solar cell string comes out of the tabber which contains 10cells in a string,the string is picked by the robot and placed on alignment plate where it is mechanical alignment.here i have to take image of cells and inspect for cracks,this is an open environment,after inspection robot has to place down to form matrix of cells.iam sending the image of cracked cell

[AnalogKid2DigitalMan]

Not an Ni solution, but I came across this today in Vision Systems Design for detecting cracks and defects in crystalline solar cells:

http://www.sensopart.com/article-95-Solar_Sensor_With_Sharp_Focus.html

-AK2DM

[F._Schubert]

It happens that I work in this industry and have once attended a trade fair for such kind of equipment. There is tons of different companies offering solutions to detect cracks and the like. Most do simple vision inspection (on a wide range of cracks and notches).

However, if you need to get other failure mechanisms (micro-cracks) as well, you need EL (electroluminescense), PL (photoluminescence) at least.

Best results you would get with a ILIT (infrared lock-in thermography). I don't know about the availability of these tools for in-line operation (*)

The other solution, but very slow is to use a LBIC (light beam induced current).

* If you are going to head for this, you should check the papers of O. Breitenstein. In one of the links posted above one of his papers is referenced. He is the 'pope' of ILIT. If you need a commercially available system, check my company's website (see my signature).

Felix

[9949633612]

any one can give some more suggestions