CN201152484Y - Multi-lamp type back light device - Google Patents

Abstract

The utility model discloses a multi-lamp type backlighting device which comprises a plurality of lamps, a plurality of balancing transformers and a high voltage source. N is a positive integer number, and the k is an integral number ranging from 1 to N. The kth balancing transformer in the balancing transformers comprises a first main coil, a second main coil and a secondary coil. The first main coil is connected with a (2k-1)th lamp in the lamps in series. The second main coil is connected with the first main coil and a 2kth lamp in series. The secondary coil corresponds to the first main coil and the second main coil. The high voltage source is electrically connected between the first main coil and the second main coil of the Nth balancing transformer.

Description

Multi-lamp type backlight device

technical field

The utility model relates to a multi-lamp type backlight device, and in particular, relates to a multi-lamp type backlight device which can use a balance transformer to control two lamps.

Background technique

In recent years, as the size of liquid crystal display panels continues to increase, backlight devices including multiple Cold Cathode Fluorescent Lamps (CCFLs) are more widely used to provide high-quality light sources required by liquid crystal display panels.

However, the biggest problem faced by the multi-lamp backlight device is how to keep the current of each lamp roughly equal to ensure that the light source provided to the liquid crystal display panel has a very stable and uniform brightness.

In order to solve the above problems, a Jin balancer circuit (Jin balancer) applicable to a multi-lamp backlight device is proposed. FIG. 1 is a schematic diagram showing a multi-lamp type backlight device having a Jin balance circuit structure in the prior art. As shown in Fig. 1, assuming that the multi-lamp type backlight device 1 includes ten lamps 12, since in the Jin balance circuit structure, one balancing transformer 2 can only be connected in series with one lamp 12, therefore, the multi-lamp type backlight device 1 requires a total Only ten balancing transformers 2 can make the lamp current flowing through each lamp 12 roughly equal.

Therefore, the utility model provides a multi-lamp backlight device to solve the above problems.

Utility model content

The utility model provides a multi-lamp type backlight device. A specific embodiment according to the utility model is a multi-lamp backlight device. The multi-lamp backlight device includes 2N lamps, N balancing transformers and a high-voltage power supply. Wherein N is a positive integer.

The N balancing transformers are electrically connected to the 2N lamps. The k-th balancing transformer among the N balancing transformers includes a first primary winding, a second primary winding, and a secondary winding. k is a positive integer ranging from 1 to N.

The first main coil is connected in series to the (2k-1)th lamp among the 2N lamps; the second main coil is connected in series between the first main coil and the 2kth lamp among the 2N lamps; The secondary coil corresponds to the first primary coil and the second primary coil, and the multiple secondary coils in the N balancing transformers are connected in series to form a loop. The high voltage power supply is electrically connected between the first main coil and the second main coil of the Nth balancing transformer.

Another specific embodiment according to the present invention is also a multi-lamp backlight device. The multi-lamp backlight device includes 2N lamps, N balancing transformers and a high-voltage power supply. Wherein N is a positive integer. k is a positive integer ranging from 1 to N, and the k-th balancing transformer among the N balancing transformers includes a main coil and a primary coil.

The primary coil is connected in series to the (2k-1)th lamp and the 2kth lamp among the 2N lamps; the secondary coil corresponds to the primary coil. The plurality of secondary coils in the N balancing transformers are connected in series to form a loop. The high-voltage power supply is electrically connected to the plurality of main coils of the N balancing transformers.

Compared with the prior art, according to the multi-lamp type backlight device of the present invention, the lamp current of two lamps can be controlled through a balance transformer, which not only can achieve the balance of each lamp current, obtain a stable and uniform current, but also simplify the The original multi-lamp type backlight device adopts a Jin balanced circuit structure to reduce the number of required balancing transformers, thus greatly reducing the cost of the product.

The advantages and spirit of the present utility model can be further understood through the following detailed description of the utility model and accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram showing a multi-lamp type backlight device having a Jin balance circuit structure in the prior art.

FIG. 2 is a schematic diagram showing a multi-lamp type backlight device according to a first embodiment of the present invention.

Fig. 3A is a schematic diagram showing that the low voltage end of the lamp is connected in series with a high voltage capacitor.

Fig. 3B is a schematic diagram showing that the high voltage end of the lamp is connected in series with a high voltage capacitor.

4A and 4B show experimental data of lamp current related to the multi-lamp backlight device shown in FIG. 2 .

FIG. 5 is a schematic diagram showing a multi-lamp type backlight device according to a second embodiment of the present invention.

6A and 6B show experimental data of lamp current related to the multi-lamp backlight device shown in FIG. 5 .

Description of main component symbols

1, 10, 50: multi-lamp backlight device 12, 52: lamp

Description of main component symbols

1, 10, 50: multi-lamp backlight device 12, 52: lamp

2, 14, 54: Balance transformer 16, 56: High voltage power supply

18: The first main coil 20: The second main coil

22, 60: secondary coil 58: main coil

Detailed ways

The first specific embodiment according to the utility model is a multi-lamp type backlight device. Please refer to FIG. 2 , which is a schematic view showing the multi-lamp backlight device. As shown in FIG. 2 , the multi-lamp backlight device 10 includes 2N lamps 12 , N balancing transformers 14 and a high voltage power supply 16 . Wherein N is a positive integer. In this example, it is assumed that N is equal to 5. Therefore, the multi-lamp backlight device 10 in FIG. 2 includes ten lamps 12 , five balancing transformers 14 and one high voltage power supply 16 in total.

In the above-mentioned multi-lamp type backlight device 10, the k-th balancing transformer 14 among the N balancing transformers 14 includes a first main coil 18, a second main coil 20, and a primary coil 22, and k ranges from 1 to A positive integer between N.

Wherein, the first main coil 18 of the k-th balancing transformer 14 is connected in series to the (2k-1)th lamp 12 among the 2N lamps 12; and the second main coil 20 of the k-th balancing transformer 14 is connected in series to the between a main coil 18 and the 2kth lamp 12 in the 2N lamps; as for the secondary coil 22 of the k balance transformer 14, it will correspond to the first main coil 18 and the second main coil 18 of the k balance transformer 14 Coil 20.

Taking the multi-lamp backlight device 10 shown in FIG. 2 as an example, for the third balance transformer 14, the first main coil 18 included in it is connected in series to the fifth lamp 12; In addition to being connected in series with the first main coil 18 of the second main coil 20, it will also be connected in series to the sixth lamp 12; The main coil 18 and the second main coil 20 .

In addition, in the multi-lamp backlight device 10, the N secondary coils 22 included in the N balancing transformers 14 are connected in series to form a loop. Therefore, the current flowing through the series loops of the N secondary coils 22 should have the same current value. As for the high voltage power supply 16 , it is electrically connected between the first main coil 18 and the second main coil 20 of the Nth balancing transformer 14 . In addition, the loop formed by the N secondary coils 22 can be coupled to a feedback circuit (not shown), and the feedback circuit can adjust the voltage value of the high voltage power supply 16 through the control circuit to make the current of the lamp 12 reach a set value.

In the same balance transformer 14, the electrode terminals of the first main coil 18, the second main coil 20 and the secondary coil 22 connected to the high-voltage capacitor are not strictly limited, so it can be a high voltage terminal or a low voltage terminal. voltage terminal. Fig. 3 is a schematic diagram showing that the electrode end of the lamp is connected in series with a high-voltage capacitor. 3A represents the situation where the low-voltage end of the lamp 12 is connected in series with a high-voltage capacitor C; FIG. 3B represents the situation where the high-voltage end of the lamp 12 is connected in series with a high-voltage capacitor C.

Regardless of whether the high-voltage capacitor is connected in series to the high-voltage end or the low-voltage end of the lamp, its main purpose is to reduce the impact on the current uniformity of each lamp caused by the difference in resistance value in the line. Assuming that the resistance values of the first main coil, the second main coil, or the lamps connected in series with the lamps are not very uniform, the deviation between the lamp currents will become larger, thus causing a negative impact on the balance effect of the lamp currents. In order to improve this phenomenon, a high-voltage capacitor with a small capacitance value can be connected in series on one side of the lamp, so that the resistance difference between the first main coil, the second main coil or the lamp itself can be ignored, thereby obtaining stable And uniform lamp current.

Please refer to FIG. 4A and FIG. 4B , the tables therein list the experimental data related to the above-mentioned multi-lamp backlight device 10 . In this experiment, the multi-lamp type backlight device according to the present invention includes twenty lamps. Figure 4A shows the lamp current values and their deviation percentages from the average value when the lamp brightness is set to 100%; Figure 4B shows the lamp current values when the lamp brightness is set to 30%. Values and their percentage deviations from the mean.

It can be seen from FIG. 4A and FIG. 4B that, with the multi-lamp backlight device of this embodiment, the deviation of each lamp current value is mostly less than 5% no matter when the lamp brightness is set to 100% or 30%. It can be seen from the above that, adopting the multi-lamp type backlight device according to the present invention can provide stable and uniform lamp current for each lamp.

The second specific embodiment according to the present invention is also a multi-lamp backlight device. Please refer to FIG. 5 , which is a schematic diagram showing the multi-lamp backlight device. As shown in FIG. 5 , the multi-lamp backlight device 50 includes 2N lamps 52 , N balancing transformers 54 and a high voltage power supply 56 . Wherein N is a positive integer. In this example, it is assumed that N is equal to 5. Therefore, the multi-lamp backlight device 50 shown in FIG.

k is a positive integer ranging from 1 to N. The k-th balancing transformer 54 among the N balancing transformers 54 includes a primary coil 58 and a primary coil 60 . The primary coil 58 is connected in series to the (2k−1)th lamp 52 and the 2kth lamp 52 among the 2N lamps 52 ; the secondary coil 60 corresponds to the primary coil 58 . N secondary coils 60 included in N balancing transformers 54 are connected in series to form a loop. The high voltage power supply 56 is electrically connected to the N main coils 58 included in the N balancing transformers 54 .

Taking the multi-lamp backlight device 50 shown in FIG. 5 as an example, in the second balance transformer 54, its main coil 58 is connected in series to the third lamp 52 and the fourth lamp 52; Coil 58.

In practice, each balancing transformer 54 has a turn ratio corresponding to the primary winding 58 and the secondary winding 60 . Since the plurality of turn ratios are substantially the same and all the secondary coils 60 have equal currents in the series loops, therefore, according to the principle of energy conservation, the lamp currents provided to each lamp 52 will also be approximately equal. equal.

In addition, the multi-lamp backlight device 50 may further include 2N high voltage capacitors. Each of the high-voltage capacitors can be connected in series with one lamp 52 among the 2N lamps 52 . In more detail, the electrode end of the lamp 52 connected in series with the high voltage capacitor can be a high voltage end or a low voltage end.

Regardless of whether the high-voltage capacitor is connected in series to the high-voltage end or the low-voltage end of the lamp, its main purpose is to reduce the impact on the current uniformity of each lamp due to the difference in resistance value in the line.

It is worth noting that the general Jin balance transformer only corresponds to one lamp, and its inductance is about 600-800mH, while the balance transformer according to the utility model can correspond to two lamps at the same time, and has a larger inductance, about 1.3H. Since the inductance of the balance transformer is related to the number of coils and its size, the balance transformer according to the utility model has more coils and a larger size than the general Jin balance transformer.

Please refer to FIG. 6A and FIG. 6B , the tables therein list the experimental data related to the above-mentioned multi-lamp backlight device 50 . In this experiment, the multi-lamp type backlight device according to the present invention includes twenty lamps. Figure 6A shows the lamp current values obtained when the lamp brightness is set to 100% and their deviation percentages from the average value; Figure 6B shows the obtained lamp current values when the lamp brightness is set to 30%. Each lamp current value and its deviation percentage from the average value.

It can be seen from FIG. 6A and FIG. 6B that, with the multi-lamp backlight device of this embodiment, the deviation of each lamp current value is mostly less than 5% no matter when the lamp brightness is set to 100% or 30%. It can be seen from the above that, adopting the multi-lamp type backlight device according to the present invention can provide stable and uniform lamp current for each lamp.

Compared with the prior art, according to the multi-lamp type backlight device of the present invention, the lamp current of the corresponding two lamps can be controlled through a balance transformer, which can not only achieve the balance of each lamp current, but also obtain a stable and uniform current, and at the same time It also simplifies the structure of the Jin balance circuit used in the original multi-lamp backlight device to reduce the number of balance transformers required, thus greatly reducing the cost of the product.

Through the detailed description of the preferred specific embodiments above, it is hoped that the features and spirit of the present utility model can be described more clearly, and the scope of the present utility model is not limited by the preferred specific embodiments disclosed above. On the contrary, the purpose is to cover various changes and equivalent arrangements within the scope of the patent scope of the utility model. Therefore, the scope of the claims of the application for the utility model should be interpreted in the broadest way based on the above description, so as to cover all possible changes and arrangements with equivalents.

Claims (9)

1, a kind of many lamps type back lighting device comprises:

2N lamp, N are a positive integer;

N balancing transformer is electrically connected to this 2N lamp, the positive integer of k scope between 1 to N, and k balancing transformer in this N balancing transformer comprises:

One first main coil, serial connection (2k-1) individual lamp to this 2N lamp;

One second main coil is serially connected with between 2k the lamp in this first main coil and this 2N the lamp; And

Primary winding, corresponding to this first main coil and this second main coil, this N in this N balancing transformer time coil tandem is to form a loop; And

One high voltage source is electrically connected between this first main coil and this second main coil of N balancing transformer.

2, many lamps type back lighting device as claimed in claim 1, wherein the coiling number of this first main coil and this second main coil and this time coil about equally.

3, many lamps type back lighting device as claimed in claim 1, wherein an electrode tip of each lamp is serially connected with a high-voltage capacitance respectively.

4, many lamps type back lighting device as claimed in claim 1, wherein this first main coil is connected between this (2k-1) individual lamp and this high voltage source.

5, many lamps type back lighting device as claimed in claim 1, wherein this second main coil is connected between this 2k lamp and this high voltage source.

6, a kind of many lamps type back lighting device comprises:

2N lamp, N are a positive integer;

N balancing transformer, the positive integer of k scope between 1 to N, k balancing transformer in this N balancing transformer comprises:

One main coil, serial connection (2k-1) individual lamp and 2k lamp to this 2N lamp; And

Primary winding, corresponding to this main coil, this N in this N balancing transformer time coil tandem is to form a loop; And

One high voltage source is electrically connected this N main coil in this N balancing transformer.

7, many lamps type back lighting device as claimed in claim 6 further comprises:

2N high-voltage capacitance, each high-voltage capacitance are connected in series with a lamp in this 2N lamp respectively.

8, many lamps type back lighting device as claimed in claim 6, wherein each balancing transformer has the number of turns ratio corresponding to this main coil and this time coil, and these a plurality of number of turns are roughly the same than all, and a feasible electric current that offers each lamp is about equally.

9, many lamps type back lighting device as claimed in claim 6, wherein an inductance value of this balancing transformer is roughly 1.3H.

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