BACKLIGHT MODULE

Abstract

A backlight module including a control unit, a backlight driving unit, a first light source set, and a second light source set is provided. The backlight driving unit is controlled by the control unit to generate a driving command to light on/off the light source sets. Therefore, the first and second light source set can be lighted on or off by turns according to a predetermined value, e.g., a time interval, times of power on operations. Otherwise, the second light source set may be used to compensate a brightness loss of the first light sources set when the displaying brightness is not enough, so as to maintain the displaying brightness within a predetermined range. Therefore, a longer lifetime of the backlight module can be obtained.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a circuit block diagram showing a conventional direct type LCD device.

FIG. 2 is a circuit block diagram showing the backlight module according to the first and third embodiment of the present invention.

FIG. 3 is a flow chart showing the control method of the first preferred embodiment.

FIG. 4 is a circuit block diagram showing the backlight module according to the second embodiment of the present invention.

FIG. 5 is a flow chart showing the control method of the second embodiment.

FIG. 6 is a graph illustrating the third embodiment according to the present invention of the backlight module having a longer lifetime, which employs an output brightness of a second light source set to compensate a brightness loss of a first light source set, so as to maintain the light sources within a predetermined range.

FIG. 7 is schematic diagram illustrating the third embodiment, in which the first light source set is not co-planar with the second light source set, and a substrate on which the first and the second light source sets are assembled can be adjusted in corporation with the space of the second light source set.

FIG. 8 is a flow chart showing the control method of the third embodiment.

FIG. 9 is a circuit block diagram showing the backlight module according to the fourth embodiment of the present invention.

FIG. 10 is a flow chart showing the control method of the fourth embodiment.

Claims

1. A backlight module, comprising: a control unit;a backlight driving unit, electrically connected to the control unit, wherein the backlight driving unit is controlled by the control unit to generate a driving command;a first light source set, electrically connected to the backlight driving unit, wherein the first light source set is turned on/off by the driving command; anda second light source set, electrically connected to the backlight driving unit, wherein the second light source set is turned on/off by the driving command;wherein the control unit controls the backlight driving unit to generate the driving command according to a predetermined value, in order to drive the first light source set and the second light source by turns.

2. The backlight module according to claim 1, wherein the predetermined value is a time interval, and the control unit comprises a timer for timing the period of power supplying, if a timing result is an odd multiple of the time interval, the backlight driving unit is controlled to generate the driving command to light on the first light source set and light off the second light source set, and if the counting result is an even multiple of the time interval, the backlight driving unit is controlled to generate the driving command to light on the second light source set and light off the first light source set.

3. The backlight module according to claim 2 further comprising a memory unit and an input unit, the memory unit and the input unit being electrically connected to the control unit, the input unit serving as an interface for users to input the predetermined value of the time interval, and the predetermined value being stored in the memory unit by the control unit.

4. The backlight module according to claim 1, wherein the predetermined value is a counting result, the control unit comprises a counter, and the counter counts the number of times of power on to obtain the counting result, if the counting result is an odd number, the backlight driving unit is controlled to generate the driving command to light on the first light source set and light off the second light source set, and if the counting result is an even number, the backlight driving unit is controlled to generate the driving command to light on the second light source set and light off the first light source set.

5. The backlight module according to claim 1, wherein the backlight driving unit comprises a plurality of backlight drivers for driving the first light source set and the second light source set, respectively.

6. A backlight module, comprising: a control unit;a backlight driving unit, electrically connected to the control unit, wherein the backlight driving unit is controlled by the control unit to generate a driving command;a first light source set, electrically connected to the backlight driving unit; anda second light source set, electrically connected to the backlight driving unit;wherein the backlight driving unit drives the first light source set, and the control unit determines whether to light on the second light source set or not according to a predetermined value simultaneouly, in order to compensate a brightness loss of the first light source set, thus maintaining a brightness of the backlight module within a predetermined range.

7. The backlight module according to claim 6, wherein a number of light sources of the first light source set is not equal to a number of light sources of the second light source set.

8. The backlight module according to claim 6, wherein the predetermined value is an decay period that a brightness of the first light source set decreases to a predetermined degree, the control unit comprises a timer for timing the period of power supplying, if the timing result does not reach the decay period, the backlight driving unit is controlled to generate the driving command to light on the first light source set and light off the second light source set, and if the timing result reaches the decay period, the backlight driving unit is controlled to generate the driving command to light on the first light source set and the second light source set simultaneously, and to make the second light source set compensate the brightness of the first light source set in a predetermined brightness displaying range.

9. The backlight module according to claim 6, wherein the first light source set is not co-planar with the second light source set.

10. The backlight module according to claim 6 further comprising a brightness detecting unit electrically connected to the control unit, for detecting a brightness of the light source sets and outputting a detected brightness value which is provided to the control unit as the predetermined value.

11. The backlight module according to claim 10, wherein the control unit determines whether the detected brightness detected by the brightness detecting unit is lower than the predetermined value, if the detected brightness is not lower than the predetermined brightness value, the backlight driving unit is controlled to generate the driving command to light on the first light source set and light off the second light source set, and if the detected brightness is lower than the predetermined brightness, the backlight driving unit is controlled to generate the driving command to light on the first light source set and the second light source set simultaneously, and to make the second light source set compensate the brightness of the first light source set in the predetermined brightness displaying range.