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Optical alignment system

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#72623

Optical alignment system | 27 August, 2014

Hi, Can anyone explain how BGA optical systems work on proffesional systems? What optics is used?( optical prisms or mirrors only)

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#72627

Optical alignment system | 27 August, 2014

The superior machines typically use only a split vision system which allows two pictures to be viewed simultaneously. The PCB (pads) and the underside (balls) of the BGA can be observed. By using micrometer screws, both exposures can be adjusted exactly congruent. An easy and accurate placement of the components is assured. Check out the Shuttlestar machines at http://www.pcb-repair.com/

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#72631

Optical alignment system | 27 August, 2014

Thank you for your reply. YES, optical alignment system allows two pictures to be viewed simultaneously but it can be achieved more ways. Do you know what method is used in the superior machines e.g.in Shuttlestar machines?

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#72632

Optical alignment system | 27 August, 2014

Sorry...prism. Typically no mirrors.

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#72638

Optical alignment system | 28 August, 2014

Thanks for the reply. So a mix of two images is made by optics(2 prisms) and ONE camera shows the result? Or there are two cameras and a mix of two images is made in video mixture device?

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#72642

Optical alignment system | 28 August, 2014

One camera is used with typically one of the following prism set-ups: The split prism system, in its most common form, is a cube made from two triangular glass prisms which are glued together at their base using polyester, epoxy, or urethane-based adhesives. Another form of prism system is the dichroic mirrored prism assembly which uses dichroic optical coatings to divide an incoming light beam

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#72643

Optical alignment system | 28 August, 2014

Thank you for your reply. For the first type of the optical alignment, do you mean something like this in the picture below?

And can you please explain a little more another form of prism system that is the dichroic mirrored prism assembly?

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#72644

Optical alignment system | 28 August, 2014

Yes, your picture is correct. Regarding the dichroic mirrored prism assembly…in this application, a dichroic material is one which causes visible light to be split up into distinct beams of different wavelengths. The original meaning of dichroic, from the Greek dikhroos, two-coloured, refers to any optical device which can split a beam of light into two beams with differing wavelengths. Such devices include mirrors and filters, usually treated with optical coatings, which are designed to reflect light over a certain range of wavelengths, and transmit light which is outside that range. An optical coating is one or more thin layers of material deposited on an optical component such as a lens or mirror which alters the way in which the optic reflects and transmits light

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#72654

Optical alignment system | 29 August, 2014

Thank you for your reply. Are you sure that it should really work as drawn? Or the mirrored ray( blue colour) will go differently because there is a total internal reflection? And the correct path of the mirrored blue ray is like that green ray?

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#72655

Optical alignment system | 29 August, 2014

Not like that.

Like this. The prism area is a partial mirror. A variable light source at Image 2 is key.

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#72656

Optical alignment system | 29 August, 2014

I'm not sure of that point, just that they are comprised of two 45 degree prisms.

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#72657

Optical alignment system | 29 August, 2014

Hi, Clarification...The point I was not sure of was Jane's last post; not Hedgemon's. I was typing while Hedgemon was posting.

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#72658

Optical alignment system | 29 August, 2014

@Hegemon: I do not think it will work properly. Why do you reckon red ray will go directly to camera? It should go up( there should be reflection). It is right angle prism. And besides I need to align two objects .One is up and the other is down, Not one left and the other down. But thanks for your reply anyway.

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