TW201138551A - Backlight module and liquid crystal display - Google Patents

Abstract

A backlight module and a liquid crystal display are provided. The liquid crystal display includes the backlight module and a liquid crystal panel disposed on one side of the backlight module. The backlight module includes n first transformers and n first lamps. The first sides of the n first transformers are received a first driving signal collectively. In the n first lamps, a first terminal of ith first lamp couples to a first terminal of a second side of ith first transformer, a second terminal of ith first lamp couples to a second terminal of a second side of (i+1)th first transformer, a first terminal of nth first lamp couples to a first terminal of a second side of nth first transformer, a second terminal of nth first lamp couples to a second terminal of a second side of 1st first transformer. n and i are positive integer, and n is greater than i.

Description

201138551

"BEZ1TW 32650twf.doc/I VI. Description of the Invention: [Technical Field] The present invention relates to a backlight module and a liquid crystal display device, and more particularly to a backlight module and a liquid crystal using the same Display device. [Prior Art]

With the advancement of modern video technology, liquid crystal display devices have been widely used in mobile phones, notebook computers (noteb〇〇k), personal computers (personal computers, NC) and personal digital assistants (pers〇nal digital). Assistant, NDA) and other consumer electronic products on the display screen. However, since the liquid crystal panel of the liquid crystal display device itself does not have the function of emitting light, it is necessary to arrange a backlight module under the liquid crystal panel to improve the light source required for the liquid crystal panel, thereby enabling the liquid crystal panel to achieve the display effect. Currently, backlight modules on the market include flat fluorescent lamps, cold cathode fluorescent lamps (CCFL), and LEDs (LED) and LEDs. S Figure 1 is a schematic diagram of a conventional backlight module. Please refer to the figure, the pressure device (such as 11G and 13G) and the four lamps 120, and the two ends of the lamp & 120 are respectively coupled to the transformer 11〇 and: a butterfly of these transformers 110 and 130: ::: sDR. In general, the two ends of the lamp 12〇 must be driven by a high voltage of different phase, so the lamp 12 mesh ^ (10) pressure device: and 130 are the same polarity transformer and 'in addition, the pressure is crying 11Γ) Fen μ _ Wang's side pressure state. The back plate of the device acts as a grounding point' and the lamp. To the LCD display, it will be configured close to

JZ1TW 32650twf.doc/I 201138551 The back plate is such that the lamp 110 forms a stray capacitance between the lamp and the back plate, which in turn affects the luminous effect of the lamp 110. In order to suppress the influence of stray capacitance, a transformer having a specific leakage inductance value is usually selected according to the characteristics of the lamp 110: and the larger the inductance value of the transformer, the better. However, in the case where the transformer inductance value is large, the lamp tube 110 is liable to flicker when it is started at a low temperature, and the efficiency of the inverter is poor. Moreover, due to the inefficient efficiency of the inverter, the temperature of the reverse converter is increased. Therefore, the components used in the inverter can operate normally at high temperatures and are insensitive to temperature, thereby increasing the inverse. The component cost of the 2 flow device. D, [Digital Description of the Invention] The present invention provides a backlight module, which can reduce the stray capacitance of the lamp, 2 to make the brightness of the lamp tube close to each other or to improve the uniformity of the # domain group. The present invention provides a liquid crystal display device. , can reduce the backlight module and can improve the efficiency of the inverter. The invention provides a backlight module </ RTI> for providing a liquid crystal display panel, a surface light source, and a backlight module comprising n first transformers and n. The primary side of the wide first transformer collectively receives a first drive. In the above 11th tube, the first end of the second side of the first transformer, the first end of the first stage of the first transformer, the first end of the first stage of the first transformer (the fourth) 1st - the secondary side of the transformer and = the ΐ of the Γϊ tube: the end consumes the "solid-transformer: the second side of the crying - Μ" brother η brother - the second end of the lamp is coupled to the first a second end of the first-transformed-sub-side, wherein, and 丨 are positive integers, and the heart

201138551 IV/~voBEZITW 32650tw£doc/I A liquid crystal display device is provided in the north of the country. It includes a liquid crystal panel and a moonlight module, and the liquid crystal panel is disposed on one side of the backlight module. The backlight module includes n first transformers and! !The first light tube. The primary sides of the eleven first transforms = collectively receive a first drive signal. In the above! The first light: the first end of the i-th first tube is coupled to the first end of the first-man side of the i-th first transformer, the first! The second end of the first lamp is lightly connected to the second end of the second side of the first-th order repeater, the _th of the nth first lamp is connected to the second side of the f-n-th transformer At the first end, the second end of the nth - 2th minus the second end of the second side of the first -th change_. In &quot;, 11 and i are positive integers, and η is greater than i. In a second embodiment, the backlight module further includes n imaginary tubes and a current comparator. The above n second variations "receive I fth drive signal. On the second end of the n second secondary side, the first second transformer and the second transformer are connected: second:: two lights The first end of the tube is coupled to the first +1 end _ nth second transformer: two two two: the second end of the first secondary side of the secondary side of the second-stage tube of the second-tube. The second end of the secondary side is composed of n; No.: the first end of the secondary side of the comparator - receives the first _ ^, the primary side of the pressure is the second of the flow comparators. a moving signal, the primary side of the n-th transforming crying of the secondary side of the flow device, the current used by the comparator to adjust the current of the primary side of the device to = current and the above-mentioned n second changes Pressure 201138551

ZlTW

32650 twf.doc/I In an embodiment of the invention, the first drive signal and the second drive signal are provided by an inverter. In the embodiment of the invention - the first drive signal is the same as the second drive signal. In the embodiment of the present invention, the primary side and the secondary side of the n first transformers are of the same polarity, and the secondary side and the secondary side of the second transformer are of the same polarity. In the embodiment of the present invention, the current comparator is a transformer, and the primary side and the secondary side of the current transformer are of different polarities. σ ... based on the above description, the backlight module and the liquid crystal display device of the present invention are coupled in series with the lamp through the secondary side of the transformer, so that the secondary side of the transformer is connected to the lamp tube in a floating state, thereby reducing the tube interference. The effect of the bulk capacitance. In this way, the luminous efficiency of the lamp can be improved, and the hardware θ cost of the transformer can be reduced, and the current required by the TIV low-reverse k-device can be increased, thereby improving the efficiency of the inverter. Moreover, in the case of series connection, the current flowing through each of the lamps will be the same, thereby improving the uniformity of the backlight module. The above described features and advantages of the present invention will become more apparent from the description of the appended claims. Embodiments Fig. 2 is an exploded view of a liquid crystal display device according to an embodiment of the present invention. Referring to FIG. 2, the liquid crystal display device 2 of the present embodiment includes a backlight module 210 and a liquid crystal display panel 220. The liquid crystal display panel 220 is disposed on one side of the backlight module 210. The backlight module 21 is configured to provide a liquid crystal display panel 220 201138551

1 yj7\j The surface light source required for BEZ1TW 32650twf.doc/I. Specifically, the liquid crystal panel 220 is disposed on a light emitting surface 240 of the backlight module 210. In addition, the liquid crystal display device 2 can have a front frame 230 ′ for the liquid crystal panel 220 to be more stably disposed on the backlight module 210. FIG. 3 is a schematic circuit diagram of the backlight module of FIG. 2 according to an embodiment of the invention. Referring to FIG. 3 , in the embodiment, the backlight module 21 〇 includes first transformers 311 314 314 and first lamps 321 324 324 , and the first lamps 321 324 324 are U-shaped tubes as an example. And the first tube 32^24 may be a cold cathode fluorescent tube. In other embodiments, the first lamps 321 324 324 may be L-shaped tubes, S-shaped tubes, or other shaped tubes. The primary sides (i.e., 311a, 312a, 313a, and 3Ma) of the first transformers 311 to 314 collectively receive the first driving signal sDR1, wherein the first driving signal Sdri may be provided by an inverter (not shown). Moreover, since the cold cathode fluorescent lamp is driven by an alternating current, the first driving signal can be a parent flow signal. The first end 32la of the first bulb 321 is coupled to the first transformer

The first end is Η. The first end 324a of the secondary side 314b of the first transformer 314 of the first lamp 324 is coupled to the first transformer

201138551 ^ ^ wv^-v-fj-z^ZlXW ^2650twf.doc/I The third side of the 3M is given the _th end G, the 324b of the first lamp 324 is coupled to the secondary side 31 of the first transformer 311 The second end b of the ratio. In this way, the first lamps 321 324 324 are lightly connected to the secondary side 3Ub, the pass, the dish and the 3 hidden series of the first variable pressure crying 311 314 314 and form a loop circuit. At this time, since the loop circuit formed by the first lamp tube 32i~ and the secondary sides 311b, 312b, 31b, and 314b of the transformers 311 314 314 is in a floating state (ie, there is no domain ground), the first lamp 321 〜 The stray capacitance of the 324 is greatly reduced, thereby reducing the effect of stray capacitance on the current. Moreover, since the secondary sides 311b, 312b, 313b, and 314b of the first transformers 311 to 314 still sense the voltages of the primary sides 311a, 312a, 313a, and 314a to generate current, the first lamps 321 to 324 can still be driven. And glow. Further, since the first lamps 321 to 324 are connected in series with the secondary sides 311b, 312b, 313b, and 314b of the first transformers 311 to 314, they flow through the lamps 321 to 324 and the secondary side 311b of the transformers 311 to 314, The currents of 312b, 313b, and 314b will be the same. At this time, even if the leakage inductance values of the first transformers si! to 3i4 are different, the current flowing through the first lamps 321 to 324 is still the same due to the coupling relationship. Therefore, since the currents flowing through the first lamps 321 to 324 are the same, the luminances of the first lamps 321 to 324 are similar or even the same, that is, the overall uniformity of the backlight module 210 is greatly improved. Moreover, in this embodiment, the four first lamps 321 324 324 need only four first transformers 311 314 314, and the first transformers 321 324 324 may not use a specific leakage inductance value, that is, a single leakage sensation may be used. Value of the transformer. Therefore, the component cost of the backlight module 210 and the manufacturing cost of the transformer can be greatly reduced.

201138551 rw^^ojBEZlTW 32650twf.doc/I Furthermore, since the first lamp tubes 321 324 324 of this embodiment are less affected by the impurity, the current can be reduced by the leakage current (4) Μ|| And the efficiency of the inverter can be. It is worth mentioning that the first transformers 311 314 314 of the present embodiment - the secondary side and the secondary side are transformers of the same polarity as an example, but in the case of the new transformer 3, the first transformer 3 &amp; 3H may be the primary side and Two owed &amp; = sex transformers. In this embodiment, the four first-lamps and the four first transformers 311-314 are used for the lamp and a plurality of the first and second meals. In the case of ηth-th tube and n first transformers=the end consumes the second side of the first first transformer: the second key of the second 第+1th-transformer=two:= :nr_n the second end of the secondary side of the first-variable voltage converter, wherein the circuit of the backlight module of the embodiment 2 of the embodiment is shown: ΐ; two; f Figure 4 'in this embodiment In the 'backlight mode, please include the fourth 422% ^^42; ^^431 421. Cry 45 〇ϋ 450 450. Also, the specific voltage regulator is exemplified here, but in other embodiments it may be realized by a current mirror or an adjustment circuit. The second side of the first transformers 4u, 4i2 is connected to the first lamp 42b 422, and the secondary side of the second intersection U 431, 432, the gamma and the second lamp phase,

32650t\vf.doc/I 201138551 wide

The coupling manner of x ^ \r \y w -A-^ Λ Λ T T 442 can be referred to the description of the above embodiment, and will not be described herein. The primary sides 411a, 412a of the first transformed state 411, 412 collectively receive the secondary side illusion of the second transformer 43b 432 of the first drive signal SDR1'. , 432a collectively receives the second drive signal Sdr2. The secondary side 450a of the current transformer 45A is coupled between the common end point b of the primary side 411a, 412a and the first driving signal SDR1, and the secondary side 450b of the current transformer 450 is coupled to the primary side 431a, 432a. Between the common endpoint 0 and the second drive signal Sdm. It is assumed here that the first driving signal sDRI is the same as the second driving signal SdR2, that is, the first driving signal SDR1 and the second driving signal are the same driving signal, so that the current flowing through the primary side 450a and the secondary side 450b will Instead, the current transformer 450 uses a transformer of a different polarity. Moreover, since the ratio of the number of lamps to be driven corresponding to the current applied to the secondary side 450b and the current of the secondary side 450b is 1. 1, the ratio of the turns of the primary side 450a and the secondary side 450b of the current transformer 450 may be 1. : 1. Furthermore, since the primary side 450a and the secondary side 45〇b of the current transformer 450 are mutually inductive, the current ratio of the right primary side 450a to the secondary side 450b is not Lu 1: 1, the primary side 450a and the secondary side 450b will interact with each other such that the current ratio between the primary side 450a and the secondary side 450b will be substantially maintained at 1:, 1. The current of the primary side 450a is the sum of the currents of the primary sides 411a, 412a, and the currents of the secondary sides 411b, 412b are generated by sensing the currents of the primary sides 4Ua, 412a, respectively. The current on the secondary side 450b is the sum of the primary side 431 &amp; 432a current, and the secondary side 431b, 432b current is generated by sensing the currents of the primary sides 431a, 432a, respectively. Due to the primary side 45〇a 10 201138551

The current of ruyuzo^BEZlTW 32650twf.doc/I is the same as the current of the secondary side 450b, so the current of the secondary side 4Ub, 412b will be substantially the same as the current of the secondary side 431b, 432b. Thereby, the brightness of the first lamps 421 and 422 is similar or even the same as that of the second tubes 441 and 442, thereby greatly improving the overall uniformity of the backlight module 2 ι.

In addition, the first transformers 4U and 412 of the present embodiment are exemplified by the change (4) of the same polarity on the secondary side of the primary side, but in the other variables, the first change, the devices 4U and 412 may be the second side and the second side. Similarly, the second transformers 43 and 432 of the present embodiment are transformers having the same polarity on the primary side and the secondary side, but in other embodiments, the second 4 31 432 may be a transformer having a different polarity on the primary side and the secondary side. If the value is 付, if the primary side 45〇a is coupled between the common end point a of the primary side 4na, 2a and the first driving signal s (four), the secondary side is connected to the common side of the primary side 431a and the fairy side. Between the point ^ and the second drive signal, then the comparator 450 can use a transformer of the same polarity. And, twice: the common end point b coupled to the primary side 4Ua, 412a is between the drive number "8" and the secondary side 45% is coupled to the common end point d of the primary side 431 &amp; The transformer of the same polarity can also be used with the second drive (four) current transformer 50. Furthermore, this embodiment is based on two first pressures = _, 412, two second lamps 441, 442 and two second ^ In the other embodiments, there may be a plurality of first s maimai pressure, a plurality of second lamps and a plurality of second transformers, 201138551

! V.V^^ZITW 3265〇twf.doc/I and the number of the first lamp is the same as the number of the second lamp. For the connection manner of the n first lamps, the n first transformers, the n second lamps, and the n second types, refer to the above embodiments, and details are not described herein again. The backlight assembly of the present invention and the liquid crystal display device are coupled in series with the first lamp through the secondary side of the first 'cross-pressure benefit, so that the secondary side of the first transformer is connected to the first tube The floating state, in order to reduce the influence of the stray capacitance of the first lamp. Thereby, the luminous efficiency of the first lamp can be improved, and the cost of the first transformer can be reduced, and the current required for the inverter can be reduced, thereby improving the efficiency of the inverter. Moreover, in the case of series coupling, the current flowing through each of the first lamps will be the same, thereby improving the uniformity of the backlight module. In addition, the present invention passes through the current regulator to adjust the current flowing through the primary side of the first transformer and the primary side of the second transformer, so that the illumination brightness of the first lamp and the first lamp are similar. The uniformity of the modules. The present invention has been disclosed in the above embodiments, and it is not intended to limit the invention to those skilled in the art, and it is possible to make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims. [Simple diagram of the figure] Figure 1 is a schematic diagram of a conventional backlight module. 2 is an exploded view of a liquid crystal display killing device according to an embodiment of the present invention. FIG. 3 is a schematic circuit diagram of the backlight module of FIG. 2 according to an embodiment of the invention. . 4 is a circuit diagram of the backlight module of FIG. 2 according to another embodiment of the present invention. 12 201138551 rv^ojBEZlTW 32650twf.doc/I Intent. [Description of main component symbols] 100, 210: backlight modules 110, 130, 311 to 314, 4H, 412, 431, 432: transformers 120, 321 to 324, 421, 422, 44 442: lamp 200: liquid crystal display Device 220. Liquid crystal pain panel 230: front frame 240: light-emitting surfaces 311a, 312a, 313a, 314a, 411a, 412a, 431a, 432a: primary side 311b, 312b, 313b, 314b, 411b, 412b, 431b, 432b: Secondary side A~H, a~d, 321a, 321b, 322a, 322b, 323a, 323b, 324a, 324b: endpoint

SdR 'SdRI, SDR2: drive signal

Claims (1)

32650twf.doc/I 201138551 A V-/V-4, W-/l-/i^ZlTW 7. Patent application scope: 1. A backlight module for providing a surface light source required for a liquid crystal display panel, including : n first transformers, the primary side of the n first transformers collectively receive a first driving signal; and n first lamps, the first end of the ith first tube is coupled to the ith first a first end of the secondary side of the transformer, a second end of the i-th first tube is coupled to a second end of the second side of the i+th first transformer, the first of the nth first tube The end is coupled to the first end of the second side of the nth first transformer, and the second end of the nth first tube is coupled to the second end of the second side of the first first transformer, where η and i Is a positive integer and η is greater than i. 2. The backlight module of claim 1, further comprising: n second transformers, wherein the primary sides of the n second transformers jointly receive a second driving signal; n second lamps, The first end of the i second tube is coupled to the first end of the secondary side of the i th second transformer, and the second end of the i th second tube is coupled to the second i + second second transformer a second end of the second side, a first end of the nth second tube is coupled to a first end of the second side of the nth second transformer, and a second end of the nth second tube is coupled to the first end a second end of the secondary side of the second transformer; and a current divider, the first end of the primary side of the current comparator receiving the first driving signal, and the second end of the primary side of the current transformer is coupled Connected to the primary side of the n first transformers, the first end of the secondary side of the current comparator receives the second driving signal, and the second end of the secondary side of the current transformer is coupled to the n second variable 14 201138551 χ v^v^-vjJBEZITW 32650twf.doc/I The primary side of the voltage device is used to connect the current of the primary side of the above-mentioned n-transformers with the above The currents on the primary side of the n second transformers are the same. 3. The method of claim 2, wherein the driving signal and the second driving signal are provided by an inverter. 4. If the application is specifically _ 2 described in the back domain 纟 1, a drive signal is the same as the second drive signal. 5. The backlight module according to item 2 of the patent application scope; t; transformer: the secondary side of the secondary side is of the same polarity, and the above-mentioned two-person &amp; For the same polarity. The flow device ^^^fiber _2 is in the form of a woven fabric, wherein the ratio is as described in the sixth section of the patent application. And a medium liquid crystal display device comprising: a liquid crystal panel; a moonlight weight group, wherein the liquid crystal side, the backlight module comprises: a 月 帛 颜 颜 | | | | | | | | | Cooperating to receive a first driving signal; and - the first side of the heart - n -th tube, the first of the i th first tube, the -w ΐ : the first end of the under side 'the i th The first end of the second side of the i+1th-transformer, the first end of the second first tube, the end of the second, the second end of the second transformer, the second end of the second pole, the first end of the second The second end of the nth first tube is coupled to the second end of the secondary side of the first first transformer, wherein η and i are positive integers, and η is greater than i. 9. The liquid crystal display device of claim 8, wherein the backlight module further comprises: n second transformers, wherein the primary side of the n second transformers collectively receive a second driving signal; a second lamp, the first end of the ith second lamp is coupled to the first end of the secondary side of the i-th second transformer, and the second end of the ith second lamp is coupled to the i+th a second end of the secondary side of the second transformer, a first end of the nth second tube is coupled to a first end of the secondary side of the nth second transformer, and a second end of the nth second tube The end is coupled to the second end of the second side of the first second transformer; and a current comparator, the first end of the primary side of the current comparator receives the first driving signal, and the primary side of the current comparator The second end is coupled to the primary side of the n first transformers, the first end of the secondary side of the current comparator receives the second driving signal, and the second end of the secondary side of the current transformer is coupled to the second end a primary side of the n second transformers, the current transformer is configured to connect the current of the primary side of the n first transformers with the n second transformers Current adjustment primary side is the same. 10. The liquid crystal display device of claim 9, wherein the first driving signal and the second driving signal are provided by an inverter. 11. The liquid crystal display device of claim 9, wherein the first driving signal is the same as the second driving signal in 16 201138551 ... jBEZITW 32650twf.doc/I. 12. The liquid crystal display device of claim 9, wherein the primary side and the secondary side of the n first transformers are of the same polarity, and the primary side and the secondary side of the n second transformers are the same polarity. 13. The liquid crystal display device of claim 9, wherein the current transformer is a transformer. 14. The liquid crystal display device of claim 13, wherein the primary side and the secondary side of the current transformer are of opposite polarity. 17