Method for testing led backlight
AssigneeSharp Kabushiki Kaisha
InventorRYUHICHI MIYOSHI
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Abstract
An LED backlight (15) having a plurality of LED groups (19) each including a plurality of LEDs (17) connected in series is tested. The LED groups (19a to 19c) are driven with a constant current respectively, and operating voltages (Vf1 to Vf3) of the LED groups (19a to 19c) are measured respectively. The LED backlight (15) is determined as normal when all of differences between the operating voltages (Vf1 to Vf3) are less than a reference value, and is determined as abnormal otherwise. With this, an open circuit failure and a short circuit failure of the LED (17) can be detected. A leakage failure of the LED (17) may be detected by switching an amount of a drive current used for driving with the constant current, to a minute current. Thus, the LED backlight is tested certainly and easily.
Claims9
A method for testing an LED backlight provided in a display device and having a plurality of LED groups each including a plurality of LEDs connected in series, the method comprising steps of:
- driving the LED groups with a constant current respectively;
- measuring operating voltages of the LED groups respectively;
- and
- determining that the LED backlight is normal when all of differences between the operating voltages are less than a reference value and determining that the LED backlight is abnormal otherwise.
A test apparatus for an LED backlight provided in a display device and having a plurality of LED groups each including a plurality of LEDs connected in series, the apparatus comprising:
- a constant current control unit configured to drive the LED groups with a constant current respectively;
- a voltage measurement unit configured to measure operating voltages of the LED groups respectively;
- and
- a determination unit configured to determine that the LED backlight is normal when all of differences between the operating voltages are less than a reference value and determine that the LED backlight is abnormal otherwise.
Dependencies are inferred from the claim text.