US 7,317,403 B2 · LED light source for backlighting with integrated electronics

Abstract

An LED backlight structure for setting voltages and currents for LEDs. Red LEDs are connected in series between a first voltage regulator and a first controllable current source, green LEDs are connected in series between a second voltage regulator and a second controllable current source, blue LEDs are connected in series between a third voltage regulator and a third controllable current source. The current sources may be linear current regulators controlled to balance the three colors to achieve a target light output of the board using a light detection chamber. PWM controllers control transistor switches connected in parallel across groups of LEDs, where the duty cycles set the average current through each group of LEDs. The control values used to achieve target light characteristics are stored in memory. The PWM controller may control brightness levels of the LEDs. The backlight may be for an LCD television.

Claims31

Dependent claims

A light emitting diode (LED) light source for use in a backlight for a display comprising:

at least one LED of a first color;
at least one LED of a second color;
at least one LED of a third color;
a plurality of current controllers, each controller connected to at least one LED of the first color, at least one LED of the second color, and at least one LED of the third color for controlling a brightness level of each color;
the at least one LED of the first color, the at least one LED of the second color, the at least one LED of the third color, and the plurality of controllers being mounted on a same circuit board;
and
a memory mounted on the circuit board, the memory storing values for controlling an output current magnitude of each of the controllers so that a combined light output of the light source has characteristics set by the values stored in the memory.

4 more elements

A method for producing a light source for use as a backlight comprising:

providing on a circuit board at least one LED of a first color, at least one LED of a second color, and at least one LED of a third color;
providing on the circuit board a plurality of current controllers, each controller connected to at least a cathode end of a respective one of the at least one LED of the first color, at least one LED of the second color, and at least one LED of the third color;
providing on the circuit board a memory, values stored in the memory determining a current output of each of the controllers;
controlling the plurality of controllers to vary brightness levels of the at least one LED of the first color, at least one LED of the second color, and at least one LED of the third color while detecting a combined light output of the at least one LED of the first color, at least one LED of the second color, and at least one LED of the third color;
determining control signals for the plurality of controllers needed to obtain a target light output of the board from the combination of the first color, second color, and third color;
and
storing in the memory values corresponding to the control signals needed to obtain the target light output.

4 more elements

Dependencies are inferred from the claim text.

LED light source for backlighting with integrated electronics

Life of this patent

LED light source for backlighting with integrated electronics

Life of this patent

Abstract

Claims31