An LCD screen does not produce light by itself. It needs an additional light source.
A Backlight is the additional light source.
A Backlight can be a CCFL, or a series of LED lights.
(Two present technologies being used)
The Toshiba Satellite A215-S7472 Notebook PC uses a CCFL.
A CCFL is a Cold Cathode Fluorescent Lamp.
Similar to Fluorescent lighting used in homes, and businesses, but on a MUCH smaller scale.
(Average size is 2mm by 334mm. In inches that is;
Approximately a little thicker than 1/16th of an inch Thick, and a little over 13 inches Long)
A screen Inverter is used to convert the power (Electricity) from the laptop, for the Backlight, and LCD screen.
Point of all this?
90 PERCENT OF THE TIME the fault is a bad Inverterhttp://www.irisvista.com/tech/laptops/toshiba-satellite-a215/disassemble-display-panel-1.htmhttp://www.zkarlo.com/selected-zkarlo-part/inverter-board-p907.php
HOWEVER, the Backlight bulb is located inside the Screen Frame, of the LCD display assembly.
An LCD screen is composed of layers. These layers are held in a specific pattern, by the LCD screen frame.
This is a thin metal frame which surrounds the LCD screen layers, and has Philips head screws which hold the frame together.
The procedure is fairly intricate.http://www.laptoprepair101.com/laptop/2007/12/09/replace-laptop-backlight-ccfl-lamp/
For additional questions please post in a Comment.
[ So far I have only seen listings for the LCD screen itself, and not a separate CCFL Backlight ]