LVDS Laptop LCD Page 2

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I do not know the right way to choose a panel but I guess you could say the right panel is one that you are able to find pin out information for and meets a few specifications.

Once you have some panels get their part numbers and see if you can find a datasheet for them.

Some places to look for datasheets are:
http://www.datasheetarchive.com/
http://www.datasheet4u.com/
http://www.alldatasheet.com/

And others you can find by googling the part number. Normally you would leave the last few digits off the part number as you will then be able to find compatible variants.

For example: My panel came from a Compaq Armada M700. The part number of the panel is LTM14C521E I was able to find a compatible datasheet here: http://www.datasheet4u.com/share_search.php?sWord=LTM14C421E&x=409&y=27 Which is for LTM14C421S.

If you open that datasheet you will notice it says "LVDS Interface" under features, it tells you the supply voltage is 3.3V and on page 6 it gives you the pin out. All important things you need to know.

It is also important to note that the backlight inverter is separate to the panel so its specifications are not covered in the data sheet only the panels requirements from the inverter are shown.

I have not been able to find a datasheet for any of my backlight inverters but if you have some knowledge of electronics you can work out how to get them going. If the laptop computer still works you can power it up then measure the signals supplied to the inverter board.

You can get a basic idea of pin out by studying the circuit board. Looking for the input bypassing capacitors on the supply connection. The control signals will go to transistor or similar buffers and the track will be thin. The ground connection will have thick track and or go to a ground plane. Often there is more than one ground connection.

Normally it has a main supply possibly in the range of 12 to 25V and a few other low voltage signals that control back light on and off and brightness normally a couple of volts. These can be produce using variable regulators like LM317. I do not recommend using resistor dividers because you can easily damage the inverter - Like I did.

If the laptop works and has brightness controls on the keyboard you can find which pin controls the brightness and the voltage range used by measuring while changing the brightness.

I have found that the inverter requirements of the LCD panel are quite similar so you should be able to mix and match inverters with panels to get a combination that you can use.

Last part required is the PC motherboard with LVDS or LVDS module that connects to the motherboard. This will be supplied with pin out information in the manual or datasheet. So you will only need to create a connecting cable to go between the interface and the panel.

Also note there are many manufactures/ distributors of embedded and industrial computer systems. They normally stock LCD panels, Inverters and Motherboards designed for this purpose. So if you have some money and do not want the challenge you can buy an off the shelf solution.

Try:
http://www.icoptech.com/index.asp
http://www.advantech.com/eplatform/
http://www.icpamerica.com/
http://www.adek.com/index.html
And others you can find with google

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