[ Back ] [ Next ]

Retail Light

Several companies place their name on a 4"x5" thin light panel.  I have seen the same product from both Kalt and Logan.  I chose the Logan product for this project because it is significantly less expensive than the others and includes a suitable AC to 9VDC adapter in the price.  The panel has a few characteristics that are worth mentioning.  It:

• uses a fluorescent lamp

• operates at 9VDC

• is about 1/4 stop brighter at the top than the bottom 

• takes 60-90 seconds from initial power on to achieve full brightness

Before gutting the viewer for this project, I  performed some measurements on it and found :

volts amps brightness 12.0 0.31 13 9.0 0.27 12.5 7.5 0.24 12 6.0 0.14 11.5

The brightness measurements were made in the center of the panel with my Sekonic L-208 after the panel was up to full brightness.  As you may determine from the above chart, I'm not to religious about running my panel at 9V.  I routinely operate it 12V and have tried it at 14V.  We can also see that the harder we push it, the more efficient it becomes.  When the voltage doubles (from 6V to 12V), the current consumption is slightly more than doubled, but the light output increases  two and a half times.

This is all well and good, but to do anything interesting with this light, we are going to have to get inside it.  To do so, we flip it over and remove six screws from the bottom.  There are four #1 and two #0 screws, so be sure you have the right tools on hand.

With the screws out, you can flip the unit back over and lift the face off.  In it you will find:

In the base: A 3mm fluorescent tube, inverter circuit to drive the tube from low voltage DC, and a switch and coaxial DC power jack A 10mm thick acrylic panel with white tape on three edges and white dots on the rear surface A highly reflective white plastic card wrapping over the lamp and behind the acrylic panel White paper shims between the reflective card and the black case

In the lid: A very thin, flexible diffuser sheet A hard, frosted plastic sheet that protects the diffuser sheet.  This is glued into the lid but can be pressed out with firm pressure.

If you decide to put your panel back together, everything should slip easily back into place and be ready to screw back together.  As you reassemble, be very careful not to damage the insulation on any of the wires.  The Fluorescent operates at very high voltages which need to be correctly contained.  Be aware of dust and dirt as you reassemble.  Any dirt that gets between the reflector and the acrylic panel will probably be invisible, but anything that touches the diffuser sheet will certainly be visible.

Treat the diffuser sheet with respect.  It is very easily damaged and very difficult to replace.  We have important plans for it and need it in pristine condition.  It would be safest  to remove it and keep it safely in an envelope until the final assembly. 

When deciding if this was a viable project, I cut a "dummy" light from plywood.  Now our job is to take that 10mm acrylic panel and cut it down to match the size of our prototype plywood.    Next

[ Top of Viewer Project ]
[ Stock Viewer ] [ Stock Light ] [ Cutting ] [ Recovery ] [ Illuminator ] [ Electronics ] [ Reflections ] [ Mount Carrier ] [ Complete? ]