Previous in Forum: Bandwidth Use   Next in Forum: Fiber Optic Routing
Close
Close
Close
12 comments
Commentator

Join Date: Oct 2010
Posts: 62
Good Answers: 5

Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/21/2010 1:34 AM

Good day my friends on CR4! I recently purchased a digital camera that had a zoom problem. I thought the problem was more complicated than it was, and took the lens assembly apart. If anyone is familiar with the read lens on a CD player, this optical assembly is very similar. It has a voice coil motor like assembly, where current is induced in several coils to position the focus lens. In trying to clean the lens, I took it apart and did not note the polarity of the magnets when I cleaned it. The Camera is a Sony DSC-H1. It would be a great help to me personally if anyone can offer me advice on the proper orientation of the magnets. Each magnet has a red mark on the side of the longest portion near a corner. It would make aligning the magnets easy-if one knew how to align the marks. Please see the pictures below: Here is the assembly, magnet side: Here is the assembly, other side: Here is the magnet side assembly, with the cover removed: And finally, here is the magnet against a keeper plate, with the red stripe (Thicker piece, mark on top) visible:

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5155
Good Answers: 279
#1

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/22/2010 6:08 AM

I did a google search for "teardown Sony DSC-H1" (you might try tear down or tear-down).

Google instant came up with a lot more stuff for the H2 (which may contain the same part). But for the H1 this might be some use:-

http://www.eserviceinfo.com/index.php?what=search2&searchstring=DSC-H1

__________________
We are alone in the universe, or, we are not. Either way it's incredible... Adapted from R. Buckminster Fuller/Arthur C. Clarke
Register to Reply
Commentator

Join Date: Oct 2010
Posts: 62
Good Answers: 5
#2
In reply to #1

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/22/2010 11:33 AM

Thank you for the link. I like the eserviceinfo they are a great resource. The link is for the level 2 service manual which only lists the lens block and gives no detail as to the components inside. Let me ask this question: in a voice coil motor, would each magnet be facing the coil be of the same pole? Like the N side of each face the coil?

Register to Reply
2
Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5155
Good Answers: 279
#3
In reply to #2

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/22/2010 1:49 PM

In these picture from Wikipedia http://en.wikipedia.org/wiki/Voice_coil

The magnet is the darker grey donut: the N pole is all over the top annulus and the S pole is all over the bottom annulus. This means that the iron pillar is S and the iron annulus is N, so that the magnetic field through the coil is radial (in to out).

(Of course it could be the other way up)

__________________
We are alone in the universe, or, we are not. Either way it's incredible... Adapted from R. Buckminster Fuller/Arthur C. Clarke
Register to Reply Good Answer (Score 2)
Commentator

Join Date: Oct 2010
Posts: 62
Good Answers: 5
#4
In reply to #3

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/22/2010 4:28 PM

You have helped me a great deal. It may have had 2 more magnets on the other side. So I am looking to create magnetic attraction with the red stripe magnets? Is that how the electromagnetic coil reacts to the field? Would it work with the magnets repelling instead of attracting?

Register to Reply
Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5155
Good Answers: 279
#5
In reply to #4

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/22/2010 5:29 PM

I think that the simple answer here is no. The trick is to get the current (i.e. the wires) running at right angles to the lines of magnetic field. The magnetic field lines run from one pole to the other.

http://en.wikipedia.org/wiki/Fleming's_left_hand_rule_for_motors

(I'm using Chrome at home: so no spell check or proper hyperlinks:- just copy the above URL into your browser)

__________________
We are alone in the universe, or, we are not. Either way it's incredible... Adapted from R. Buckminster Fuller/Arthur C. Clarke
Register to Reply
Commentator

Join Date: Oct 2010
Posts: 62
Good Answers: 5
#6
In reply to #5

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/22/2010 6:23 PM

So I need to get each set of magnets attracting each other. Given the distance between the magnets, do you think there would be an alignment between the two blocks? Or is it as simple as getting both magnets on each side to attract then re assembling? What I am trying to say is that do you think that I should align each set of two magnets for a total of 4 aligned magnets? I truly appreciate your help.

Register to Reply
Commentator

Join Date: Oct 2010
Posts: 62
Good Answers: 5
#8
In reply to #5

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/23/2010 12:16 PM

Randall, I took the lens assembly further apart and discovered that the magnets on the opposing side also had red marks on them. At that point is was just a matter of aligning the marks and re assembling the unit. It works fine now. I thank you for your help and will mention you and CR4 by name on the instructable I will publish on how to repair a Sony Lens system. Thanks again!

Register to Reply Score 1 for Good Answer
Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5155
Good Answers: 279
#9
In reply to #8

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/23/2010 3:14 PM

Great, Thanks for keeping us updated.

Hope to see some nice winter pics. here soon.

__________________
We are alone in the universe, or, we are not. Either way it's incredible... Adapted from R. Buckminster Fuller/Arthur C. Clarke
Register to Reply Off Topic (Score 5)
Commentator

Join Date: Oct 2010
Posts: 62
Good Answers: 5
#10
In reply to #9

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/23/2010 5:02 PM

You've got it my friend! Now, if I can just keep it from focusing on the dust inside the lenses!!!

Register to Reply Off Topic (Score 5)
Commentator

Join Date: Oct 2010
Posts: 62
Good Answers: 5
#7

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/22/2010 8:32 PM

I am 80% closer to getting this together. If we consider lines of flux, even if both L and R assemblies are properly aligned, and in proper relation to each other, all in attraction, then there are still 2 more combinations, and I am not positive if it would have any kind of effect on it at all. The mechanism itself moves laterally and not up and down, I suppose searching for a perfect position. If so and I get it wrong, then it is possible the sensors function moving one way or another until the focus is right. If so, then the orientation really is not that important.

Register to Reply
Commentator

Join Date: Oct 2010
Posts: 62
Good Answers: 5
#11

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/25/2010 12:13 PM

Randall, here are the pictures that I could manage to upload. I ended up cleaning the inside lens of the outer lens assembly with scratch free microfiber cloth, and it scratched the lens pretty bad, but the camera works fine. Some pics were shot before I "cleaned" the inside lens and scratched it, others were shot after. Overall I am happy with how it turned out. Macro of a muffler for an air compressor: I am in the high desert of California, 4,000 feet above sea level. In some of these pictures I was at the cloudline. Thank you again and Merry Christmas! (I have just one complaint of CR4, why is it we are not able to post the HTML code? Such as: <a href="http://photobucket.com" target="_blank"><img src="http://img.photobucket.com/albums/v237/wolfmangk/Desert/DSC00020_1024x768.jpg" border="0" alt="Photobucket"></a> ?)

Register to Reply
Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5155
Good Answers: 279
#12
In reply to #11

Re: Electromagnetic Positioning Focusing Mechanism Magnet Orientation in a Digcam

12/28/2010 10:08 AM

Wow, great pictures of awesome scenery. You have been well rewarded for persevering when many others would have given up. I can't tell which shots were taken with the dust and which with the scratches, but I guess that the originals are much bigger than my screen.

I hope you had a good Xmas, and are looking forward to some long walks in the high desert in the new year.

__________________
We are alone in the universe, or, we are not. Either way it's incredible... Adapted from R. Buckminster Fuller/Arthur C. Clarke
Register to Reply
Register to Reply 12 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!

Previous in Forum: Bandwidth Use   Next in Forum: Fiber Optic Routing

Advertisement