This application claims priority to Taiwan Application Serial Number 97136941, filed Sep. 25, 2008, which is herein incorporated by reference.
1. Field of Invention
The present invention relates to a backlight module and an operating method thereof. More particularly, the present invention relates to a side-type backlight module and an operating method thereof.
2. Description of Related Art
The side-type backlight module can direct light from its lateral faces to the top surface for providing uniform light. The back light source of the side-type backlight module may include cold cathode fluorescent lamps (CCFL), light-emitting diode (LED) or the like. LED has gradually replaced CCFL in display field, because they are very small, lower power consumption, long working life, lower driving voltage, stronger shock resistance and so forth.
In general, the LED light sources are disposed on the lateral face, and have equal pitches between each LED light sources.
However, the equal pitches among the LED light sources cause a difference of power density and heat dissipation capability in different places of the light guide plate, which results in unbalanced temperature distribution or high temperature gathered at some places of the light guide plate. Thus, the light density of the backlight module will not uniform, and the light guide plate may be warped; therefore, the reliability of the side-type backlight module is reduced.
In view of the foregoing, there is a need in the related field to provide a suitable side-type backlight module and a method for operating the side-type backlight module.
The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the present invention or delineate the scope of the present invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.
In one aspect, the present invention is directed to a side-type backlight module.
According to one embodiment of the present invention, the side-type backlight module comprises a light guide plate and a plurality of LED light sources. The light guide plate comprises a lateral face. The LED light sources are disposed on the lateral face, wherein every two adjacent LED sources are spaced by a pitch and the pitches between each two LED light sources are difference. Thus, the problem of the unbalanced temperature distribution is solved, thereby the quality of light is unaffected, and the appearance of the warped light guide plate is prevented.
According to another embodiment of the present invention, the side-type backlight module comprises a light guide plate, a plurality of first LED light sources, a plurality of second LED light sources, a plurality of third LED light sources and a plurality of fourth LED light sources. The light guide plate comprising a first lateral face, a second lateral face, a third lateral face and a fourth lateral face, where the first lateral face is opposite to the second lateral face, and the third lateral face is opposite to the fourth lateral face; the first lateral face is connected with the third and fourth lateral faces, the second lateral face is connected with the third and fourth lateral faces. The first LED light sources are disposed on the first lateral face, wherein every two adjacent first LED sources are spaced by an first pitch, thereby a plurality of the first pitches are arranged among the first LED light sources, wherein at least one minimum first pitch of the first pitches is positioned nearest to a center of the first lateral face; the second LED light sources are disposed on the second lateral face, wherein every two adjacent second LED sources are spaced by a second pitch, thereby a plurality of the second pitches are arranged among the second LED light sources, wherein at least one minimum second pitch of the second pitches is positioned nearest to a center of the second lateral face; the third LED light sources disposed on the third lateral face, wherein every two adjacent third LED sources are spaced by an third pitch, thereby a plurality of the third pitches are arranged among the third LED light sources, wherein at least one minimum third pitch of the third pitches is positioned nearest to a center of the third lateral face; the fourth LED light sources disposed on the fourth lateral face, wherein every two adjacent fourth LED sources are spaced by an fourth pitch, thereby a plurality of the fourth pitches are arranged among the fourth LED light sources, wherein at least one minimum fourth pitch of the fourth pitches is positioned nearest to a center of the fourth lateral face. Thus, the problem of the unbalanced temperature distribution is solved, thereby the quality of light is unaffected, and the appearance of the warped light guide plate is prevented.
In another aspect, the present invention is directed to a method for operating a side-type backlight module.
According to another embodiment of the present invention, the method for operating the side-type backlight module is accomplished, wherein the side-type backlight module comprises a light guide plate comprising a lateral face and a plurality of LED light sources disposed on the lateral face. The method is performed to drive the LED light sources in such a way that powers of the LED light source are varied. Thus, the problem of the unbalanced temperature distribution is solved, thereby the quality of light is unaffected, and the appearance of the warped light guide plate is prevented.
According to another embodiment of the present invention, the method for operating the side-type backlight module is accomplished, wherein the side-type backlight module comprises a light guide plate, a plurality of first LED light sources, a plurality of second LED light sources, a plurality of third LED light sources and a plurality of fourth LED light sources. The light guide plate comprises a first lateral face, a second lateral face, a third lateral face and a fourth lateral face, where the first lateral face is opposite to the second lateral face, and the third lateral face is opposite to the fourth lateral face; the first lateral face is connected with the third and fourth lateral faces, and the second lateral face is connected with the third and fourth lateral faces. The first LED light sources are disposed on the first lateral face; the second LED light sources are disposed on the second lateral face; the third LED light sources are disposed on the third lateral face; the fourth LED light sources are disposed on the fourth lateral face. The method is performed to drive the first, second, third and fourth LED light sources in such a way that powers of first, second, third and fourth LED light sources are varied. Thus, the problem of the unbalanced temperature distribution is solved, thereby the quality of light is unaffected, and the appearance of the warped light guide plate is prevented.
The present description will be better understood from the following detailed description read in light of the accompanying drawings, wherein:
Like reference numerals are used to designate like parts in the accompanying drawings.
The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.
In one aspect, the present invention is directed to a side-type backlight module. The side-type backlight module may be easily inserted into displays and may be applicable or readily adaptable to all technologies. Herewith a side-type backlight module is illustrated by reference to the following descriptions considered in
In the side-type backlight module, a plurality of LED light sources may be disposed on one lateral face of the light guide plate in a longitudinal direction. In general, every two adjacent LED sources are spaced by a pitch, and the pitches arranged among the LED light sources are the same. Thus, the temperature distribution of the lateral face of the light guide plate is unbalanced.
For the foregoing reasons, please refer to
Accordingly, the varied pitches 161,162 and 163 are arranged among the LED light sources 120 for preventing the unbalanced temperature distribution of the lateral face 112 of the light guide plate 110.
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Accordingly, the varied pitches 261,262 and 263 are arranged among the LED light sources 120, so as to prevent the unbalanced temperature distribution of the lateral face 112 of the light guide plate 110.
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The light guide plate 210 comprises a first lateral face 211, a second lateral face 212, a third lateral face 213 and a fourth lateral face 214. The first lateral face 211 is opposite to the second lateral face 212; the third lateral face 213 is opposite to the fourth lateral face 214. The first lateral face 211 is connected with the third and fourth lateral faces 212 and 214; the second lateral face 212 is connected with the third and fourth lateral faces 213 and 214.
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In another aspect, the present invention is directed to a method for operating a side-type backlight module. The method may be easily applied in displays and may be applicable or readily adaptable to all technologies. Herewith one or more methods for operating the side-type backlight module is illustrated by reference to the following description considered in
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For a more complete understanding of the method for driving the side-type backlight module 400, the first and second embodiments are illustrated by reference to the following description considered in
Moreover, at least one LED light sources 124 positioned nearest to margins of the lateral face 112 receives at least one maximum current of the adjustable currents. Thus, it is prevented that the temperature of the margins of the lateral face 112 is lower than the temperature of the center of the lateral face 112.
Moreover, the adjustable currents received by the LED light sources 121,122,123 and 124 are gradually increased along a longitudinal direction from the center to the margins of the lateral face 112. In other words, the adjustable current received by the LED light sources 121 is lower than the adjustable current received by the LED light sources 122; the adjustable current received by the LED light sources 122 is lower than the adjustable current received by the LED light sources 123; the adjustable current received by the LED light sources 123 is lower than the adjustable current received by the LED light sources 124. Thus, power consumption and heat dissipation capacity of the lateral face 112 of the light guide plate 110 are balanced, so that the temperature distribution of the lateral face 112 of the light guide plate 110 is uniform.
In the second embodiment, a plurality of pulse currents is generated by means of pulse-width modulation, and the pulse currents is inputted into the LED light sources 121,122,123 and 124 respectively, peak values of the pulse currents being substantially equal, wherein each of the pulse currents has a duty cycle, and at least one LED light source 121 of the LED light sources 121,122,123 and 124 positioned nearest to the center of the lateral face 112 receives at least one of the pulse currents having a minimum duty cycle. Thus, a state of high temperature of the center of the lateral face 112 is avoided.
Moreover, at least one LED light sources 124 positioned nearest to the margins of the lateral face 112 receives at least one of the pulse currents having a maximum duty cycle. Thus, it is prevented that the temperature of the margins of the lateral face 112 is lower than the temperature of the center of the lateral face 112.
Moreover, the LED light sources 121,122,123 and 124 receives the pulse currents respectively, and the duty cycles of the pulse currents are gradually increased along a longitudinal direction from the center to the margins of the lateral face. In other words, the duty cycle of the pulse current of the LED light sources 121 is lower than the duty cycle of the pulse current of the LED light sources 122; the duty cycle of the pulse current of the LED light sources 122 is lower than the duty cycle of the pulse current of the LED light sources 123; the duty cycle of the pulse current of the LED light sources 123 is lower than the duty cycle of the pulse current of the LED light sources 124. Thus, power consumption and heat dissipation capacity of the lateral face 112 of the light guide plate 110 are balanced, so that the temperature distribution of the lateral face 112 of the light guide plate 110 is uniform.
Moreover, the pitches among the LED light sources 121,122,123 and 124 may be substantially equal; alternatively, the pitches among the LED light sources 121,122,123 and 124 may be varied, such as the arrangement of the pitches shown in
Please refer to
The light guide plate 210 comprises a first lateral face 211, a second lateral face 212, a third lateral face 213 and a fourth lateral face 214. The first lateral face 211 is opposite to the second lateral face 212; the third lateral face 213 is opposite to the fourth lateral face 214. The first lateral face 211 is connected with the third and fourth lateral faces 213 and 214; the second lateral face 212 is connected with the third and fourth lateral faces 213 and 214.
The first LED light sources 511,512,513 and 514 are disposed on the first lateral face 211. The second LED light sources 521,522,523 and 524 disposed on the second lateral face 212. The third LED light sources 531,532 and 533 are disposed on the third lateral face 213. The fourth LED light sources 541,542 and 543 are disposed on the fourth lateral face 214.
The method for operating the side-type backlight module 500 is performed to driving the first, second, third and fourth LED light sources in such a way that powers of first, second, third and fourth LED light sources are varied.
For a more complete understanding of the method for driving the side-type backlight module 500, the third and fourth embodiments are illustrated by reference to the following description considered in
In the third embodiment, a plurality of first adjustable currents are generated by means of analog modulation, and the first adjustable currents are inputted into the first LED light sources 511,512,513 and 514 respectively, wherein at least one first LED light source 511 of the first LED light sources 511,512,513 and 514 positioned nearest to a center of the first lateral face 211 receives a minimum current of the first adjustable currents; a plurality of second adjustable currents are generated by means of the analog modulation, and the second adjustable currents are inputted into the second LED light sources 521,522,523 and 524 respectively, wherein at least one second LED light source 521 of the second LED light sources 521,522,523 and 524 positioned nearest to a center of the second lateral face 212 receives a minimum current of the second adjustable currents; a plurality of third adjustable currents are generated by means of the analog modulation, and the third adjustable currents are inputted into the third LED light sources 531,532 and 533 respectively, wherein at least one third LED light source 531 of the third LED light sources 531,532 and 533 positioned nearest to a center of the third lateral face 213 receives a minimum current of the third adjustable currents; a plurality of fourth adjustable currents are generated by means of the analog modulation, and the fourth adjustable currents are inputted into the fourth LED light sources 541,542 and 543 respectively, wherein at least one fourth LED light source 541 of the fourth LED light sources 541,542 and 543 positioned nearest to a center of the fourth lateral face 214 receives a minimum current of the fourth adjustable currents. Thus, a state of high temperature of the center of each lateral face of the light guide plate 210 is avoided.
Moreover, at least one first LED light source 514 positioned nearest to margins of the first lateral face 211 receives at least one maximum current of the first adjustable currents; at least one second LED light source 524 positioned nearest to margins of the second lateral face 212 receives at least one maximum current of the second adjustable currents; at least one third LED light source 533 positioned nearest to margins of the third lateral face 213 receives at least one maximum current of the third adjustable currents; at least one fourth LED light source 543 positioned nearest to margins of the fourth lateral face 214 receives at least one maximum current of the fourth adjustable currents. Thus, it is prevented that the temperature of the margins of each lateral face of the light guide plate 210 is lower than the temperature of the center of each lateral face of the light guide plate 210.
Moreover, the first adjustable currents received by the first LED light sources 511,512,513 and 514 are gradually increased from the center to the margins of the first lateral face 211; the second adjustable currents received by the second LED light sources 521,522,523 and 524 are gradually increased from the center to the margins of the second lateral face 212; the third adjustable currents received by the third LED light sources 531,532 and 533 are gradually increased from the center to the margins of the third lateral face 213; the fourth adjustable currents received by the fourth LED light sources 541,542 and 543 are gradually increased from the center to the margins of the fourth lateral face 214. Thus, the temperature distribution of each lateral face of the light guide plate 210 is uniform.
In the fourth embodiment, a plurality of first pulse currents are generated by means of pulse-width modulation, and the first pulse currents are inputted into the first LED light sources 511,512,513 and 514 respectively, peak values of the first pulse currents being substantially equal, wherein each of the first pulse currents has a first duty cycle, and at least one first LED light source 511 of the first LED light sources 511,512,513 and 514 positioned nearest to the center of the first lateral face receives at least one of the first pulse currents having a minimum duty cycle of the first duty cycles; a plurality of second pulse currents are generated by means of the pulse-width modulation, and the second pulse currents are inputted into the second LED light sources 521,5122,523 and 524 respectively, peak values of the second pulse currents being substantially equal, wherein each of the second pulse currents has a second duty cycle, and at least one second LED light source 521 of the second LED light sources 521,5122,523 and 524 positioned nearest to the center of the second lateral face 212 receives at least one of the second pulse currents having a minimum duty cycle of the second duty cycles; a plurality of third pulse currents are generated by means of the pulse-width modulation, and the third pulse currents are inputted into the third LED light sources 531,532 and 533 respectively, peak values of the third pulse currents being substantially equal, wherein each of the third pulse currents has a third duty cycle, and at least one third LED light source 531 of the third LED light sources 531,532 and 533 positioned nearest to the center of the third lateral face 213 receives at least one of the third pulse currents having a minimum duty cycle of the third duty cycles; a plurality of fourth pulse currents are generated by means of the pulse-width modulation, and the fourth pulse currents are inputted into the fourth LED light sources 541,542 and 543 respectively, peak values of the fourth pulse currents being substantially equal, wherein each of the fourth pulse currents has a fourth duty cycle, and at least one fourth LED light source 541 of the fourth LED light sources 541,542 and 543 positioned nearest to the center of the fourth lateral face 214 receives at least one of the fourth pulse currents having a minimum duty cycle of the fourth duty cycles. Thus, a state of high temperature of the center of each lateral face of the light guide plate 210 is avoided.
Moreover, at least one first LED light source 514 positioned nearest to the margins of the first lateral face 211 receives at least one of the first pulse currents having a maximum duty cycle of the first duty cycles; at least one second LED light source 524 positioned nearest to the margins of the second lateral face 212 receives at least one of the second pulse currents having a maximum duty cycle of the second duty cycles; at least one third LED light source 533 positioned nearest to the margins of the third lateral face 213 receives at least one of the third pulse currents having a maximum duty cycle of the third duty cycles; at least one fourth LED light source 534 positioned nearest to the margins of the fourth lateral face 214 receives at least one of the fourth pulse currents having a maximum duty cycle of the fourth duty cycles. Thus, it is prevented that the temperature of the margins of each lateral face of the light guide plate 210 is lower than the temperature of the center of each lateral face of the light guide plate 210.
Moreover, the first LED light sources 511,512,513 and 514 receive the first pulse currents respectively, and the first duty cycles of the first pulse currents are gradually increased from the center to the margins of the first lateral face 211; the second LED light sources 521,522,523 and 524 receives the second pulse currents respectively, and the second duty cycles of the second pulse currents are gradually increased from the center to the margins of the second lateral face 212; the third LED light sources 531,532 and 533 receive the third pulse currents respectively, and the third duty cycles of the third pulse currents are gradually increased from the center to the margins of the third lateral face 213; the fourth LED light sources 541,542 and 543 receives the fourth pulse currents respectively, and the fourth duty cycles of the fourth pulse currents are gradually increased from the center to the margins of the fourth lateral face 214. Thus, the temperature distribution of each lateral face of the light guide plate 210 is uniform.
Moreover, the pitches among the LED light sources may be varied, such as the arrangement of the pitches shown in
In an alternative embodiment, the pitches among the LED light sources are substantially equal. In this manner, the first LED light sources 511,512,513 and 514 receive the first pulse currents respectively, and the first duty cycles of the first pulse currents are gradually decreased from the center to the margins of the first lateral face 211; the second LED light sources 521,522,523 and 524 receives the second pulse currents respectively, and the second duty cycles of the second pulse currents are gradually decreased from the center to the margins of the second lateral face 212; the third LED light sources 531,532 and 533 receive the third pulse currents respectively, and the third duty cycles of the third pulse currents are gradually decreased from the center to the margins of the third lateral face 213; the fourth LED light sources 541,542 and 543 receives the fourth pulse currents respectively, and the fourth duty cycles of the fourth pulse currents are gradually decreased from the center to the margins of the fourth lateral face 214.
It will be understood that the above description of embodiments is given by way of example only and that various modifications may be made by those with ordinary skill in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments of the invention. Although various embodiments of the invention have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those with ordinary skill in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention.
Number | Date | Country | Kind |
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97136941 | Sep 2008 | TW | national |