CN1577460A - Driver for planar Display - Google Patents
Driver for planar Display Download PDFInfo
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- CN1577460A CN1577460A CN 03133158 CN03133158A CN1577460A CN 1577460 A CN1577460 A CN 1577460A CN 03133158 CN03133158 CN 03133158 CN 03133158 A CN03133158 A CN 03133158A CN 1577460 A CN1577460 A CN 1577460A
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Abstract
The present invention is one kind of drive device for planar display. The planar display includes one display panel and at least two lamps serves as the back light source. The drive device includes two transformers with the primary side and the secondary side, and the two transformers have their primary sides connected to one resonant circuit and the secondary sides to one of the lamps separately for lighting. The two transformers have the primary windings in the same polarity, and one of the secondary windings are wound inversely to form the inverse polarity.
Description
Technical field
The present invention refers in particular to the drive unit that is applied to the back light in the LCD about a kind of flat display driving device.
Background technology
The general closed planar display, for example (liquid crystal display, LCD), it has a display panels, a back light (backlight source) and a drive unit to a LCD.Drive unit is for driving back light so that back light provides light source to illuminate display panels.
See also Fig. 1, Fig. 1 is the synoptic diagram of the drive unit 10 of known LCD.Drive unit 10 is used to drive the back light that comprises two cold cathode ray tubes 18.Drive unit 10 comprises a resonant circuit 12 (resonance circuit), two start-up circuits 14 and two transformers 16 (transformer).Two transformers 16 all drive to recommend (push-pull) mode.Each transformer 16 all comprises primary side (primary side) and secondary side (secondary side).Resonant circuit 12 provides three groups of windings (windings) in side place each time, and it is respectively first winding 20, second winding 22 and the tertiary winding 24.Each start-up circuit 14 provides one the 4th winding 26 in this corresponding secondary side place.One end of each start-up circuit 14 is connected with corresponding cold cathode ray tube 18, and the other end is ground connection then.Resonant circuit 12 in order to provide suitable and stable electric current to be positioned at this each time this group winding (windings) of side locate, via each transformer 16 coupling (coupling), export a trigger voltage respectively in the 4th winding 26 of this every secondary side.This trigger voltage is in order to light corresponding cold cathode ray tube 18.In the drive unit 10, the polarity that all windings of two transformers 16 form is all identical.
See also Fig. 2, Fig. 2 is the drive waveforms figure of two transformers, 16 secondary sides of Fig. 1.Among Fig. 2, L1 and L2 are the drive waveforms that two transformers 16 of drive unit 10 produce separately at secondary side, and L then is the composite wave of L1 and L2.Because known drive unit 10 is given this group winding that is positioned at two transformers, 16 primary sides by same resonant circuit 12 supplying electric currents, therefore two transformers, 16 secondary sides will produce driving ripple L1, the L2 of two same frequencys, phase differential and amplitude, after synthetic, the composite wave L that enlarges will be produced.Be harmful to for health and can disturb the electronic signal generation owing to drive ripple, therefore relevant dealer there's no one who doesn't or isn't is devoted to study the technology of minimizing drive waveforms one-tenth.
See also Fig. 3, Fig. 3 is the synoptic diagram of known another drive unit 28.United States Patent (USP) the 6th, 515 provides a kind of drive unit 28 No. 427.Transformer at the push pull mode driving, drive unit 28 changes second winding, the 22 formed polarity of transformer 16 primary sides of known drive unit 10, by second winding, 30 coils back-roll, to form opposite polarity with the primary side of a transformer 16 in two transformers 16.Two driving wave frequencies and amplitude that drive unit 28 is produced two transformers, 16 primary sides are identical, but waveform reaches the phase differential of 180 degree.After the coupling equimultiple enlarged voltage, the two driving ripples that described secondary side produced can mutually offset.
Yet, scrutinize drive unit 28, after 16 couplings of two transformers, its phase differential will very likely change, and can't reach 180 degree, therefore after the coupling equimultiple enlarges voltage, this two drivings ripple can not mutually offset fully, even if application target is for the interference that alleviates on the picture is enough, yet to suppress countermeasure just accurate inadequately if will be used as the low-frequency current field radiation, and improved effect is had a greatly reduced quality.
Summary of the invention
A purpose of the present invention provides a kind of drive unit that is applied to LCD, in order to solve the problem that known technology produced.
The invention provides a kind of flat display driving device that is used in.Flat-panel screens comprises a display panel, and at least two lamps are used as the back light of display panel.Drive unit of the present invention comprises two transformers.Each transformer includes primary side and secondary side, and the primary side of described transformer is connected with a resonant circuit, and the secondary side of each transformer then is connected to be used for lighting lamp with a corresponding lamp.First side winding polarity in this two transformer is identical, and has the secondary side winding coil of a transformer to rewind to form opposite polarity in this two transformer.
Drive unit of the present invention rewinds the secondary side winding coil of a transformer in two transformers to form opposite polarity, and the winding coil by two secondary sides drives wave phase control, make the driving ripple that secondary side produced of two transformers, its frequency and amplitude are identical, and phase differential is maintained at 180 degree.Therefore the drive waveforms that secondary side produced of two transformers will mutually offset, and can suppress the radiation of low-frequency current field.Drive unit of the present invention does not comprise other ELECTROMAGNETIC OBSCURANT materials, still can significantly reduce the influence that drives wave interference.And drive unit of the present invention is not limited to only utilize a resonant circuit, also is not limited to only utilize the line construction of push pull mode.
Description of drawings
Can be further understood by the following detailed description and accompanying drawings about the advantages and spirit of the present invention.
Fig. 1 is the synoptic diagram of known drive unit.
Fig. 2 is the drive waveforms figure of two Circuit Fault on Secondary Transformer of Fig. 1.
Fig. 3 is the synoptic diagram of known another drive unit.
Fig. 4 is the synoptic diagram of the drive unit of the present invention's first specific embodiment.
Fig. 5 is the drive waveforms figure of Circuit Fault on Secondary Transformer of the drive unit of Fig. 4
Fig. 6 is the synoptic diagram of the drive unit of the present invention's second specific embodiment.
The drawing reference numeral explanation
10: known drive unit 12: resonant circuit
14: start-up circuit 16: transformer
18: 20: the first windings of lamp
Winding 24 in 22: the second: the tertiary winding
26: the four windings
L1, L2: the drive waveforms of known drive unit
The composite wave 28 of L:L1 and L2: known drive unit
Winding 40 in 30: the second: drive unit of the present invention
42: resonant circuit 44: start-up circuit
46: winding 48: winding
50: drive unit 52 of the present invention: resonant circuit
D1, D2: the drive waveforms of drive unit
The composite wave of D:D1 and D2
Embodiment
See also Fig. 4, Fig. 4 is the synoptic diagram of the drive unit 40 of the present invention's first specific embodiment.Drive unit 40 can be provided with in the LCD.This LCD comprises a display panels (not shown) and two lamps.This two lamp can be cold cathode ray tube (cold cathode Fluorescent Lamp, CCFL) 18, be used as the back light (backlight source) of this display panels.
Drive unit 40 comprises a resonant circuit 42 (resonance circuit), two start-up circuits 14 and two transformers 16 (transformer).Two transformers 16 are with a kind of type of drive, for example all can be push pull mode or full-bridge (full-bridge) mode, and present embodiment are example with the push pull mode.Each transformer 16 has primary side (primary side) and secondary side (secondary side).The primary side of transformer 16 is connected with resonant circuit 42, and resonant circuit 42 provides one group of winding (winding) 44 in side place each time.The secondary side of each transformer 16 then is connected with a lamp 18 respectively.
Two start-up circuits 14 provide two windings in the secondary side place of this corresponding transformer 16, wherein, the back-roll of a winding 46 coils, 48 of another windings do not rewind.One end of each start-up circuit 14 is connected with corresponding lamp 18, and the other end is ground connection then.
Resonant circuit 42 provides suitable and stable electric current to the winding 44 (winding) of the primary side that is positioned at each transformer 16 to locate, via 16 couplings (coupling) of each transformer, export a trigger voltage respectively in the winding 46,48 of the secondary side of each transformer 16.This trigger voltage is then in order to light corresponding lamp 18.
Two windings, 44 polarity of primary side that are positioned at two transformers 16 are identical.And the secondary side winding coil that a transformer 16 is arranged in two transformers 16 rewinds to form opposite polarity, and the winding coil of these two secondary sides of mat drives wave phase control, make the driving ripple that secondary side produced of two transformers 16, its frequency and amplitude are all identical, and phase differential is maintained at 180 degree.
See also Fig. 4 and Fig. 5, Fig. 5 is the drive waveforms figure of transformer 16 secondary sides of the drive unit 40 of Fig. 4.The result of drive unit 40 of the present invention such as Fig. 5, wherein D1 and D2 are the drive waveforms that two transformers 16 of drive unit 50 produce separately at its secondary side, and D is the composite wave of D1 and D2.As shown in Figure 5, by the present invention can really reach two transformers 16 secondary side produced two drives the effect that ripples mutually offset.Drive unit of the present invention does not utilize other ELECTROMAGNETIC OBSCURANT materials, and utilizes two frequencies identical and drive waveforms that phase place is opposite is offseted each other, suppresses the radiation of low-frequency current field.
See also Fig. 6, Fig. 6 is the synoptic diagram of the drive unit 50 of the present invention's second specific embodiment.The present invention also can be applicable to one group of resonant circuit the design of electric current to the primary side of a transformer only is provided.In second specific embodiment, drive unit 50 comprises two resonant circuits 52, two start-up circuits 14 and two transformers 16.Two transformers 16 use with a kind of type of drive.The drive unit 50 of second embodiment and the drive unit of first embodiment, 40 main difference parts are resonant circuit, and remaining configuration and type of drive are then similar.52 of each resonant circuits of drive unit 50 are corresponding to one of them of two transformers 16, among this and first embodiment, and resonant circuit 42 direct corresponding two transformers, 16 differences of drive unit 40.
In the drive unit of the present invention, the corresponding lamp number of transformer does not limit one, and the lamp kind is not limited to cold cathode ray tube.In addition, under the identical situation of lamp quantity that each start-up circuit 14 connects, each start-up circuit 14 a plurality of lamps that can be connected in parallel.Application of the present invention has more than the line construction that is limited to push pull mode, as long as the type of drive of two transformers is identical.
More known drive unit 28 (Fig. 3), wherein, two primary sides need to provide electric current by same resonant circuit, and its only suitable line construction of recommending form, thereby known drive unit 28 restriction to some extent on using.40,50 of drive units of the present invention are not limited to only utilize a resonant circuit, also are not limited to only utilize the line construction of push pull mode.
And, learn that through experiment known drive unit 28 can't overcome the phase differential that is produced after 16 couplings of two transformers, and the radiation of its low-frequency current field is about 1.5V/m.Compare with known drive unit 28, drive unit of the present invention makes that this two frequency is identical and drive waveforms that phase place is opposite is offseted each other, suppresses the radiation of low-frequency current field.Even do not utilize other ELECTROMAGNETIC OBSCURANT materials, in the drive unit of the present invention, the reading of measured low-frequency current field radiation (reading data) can be reduced to 0.8V/m-0.3V/m.
By the detailed description of above preferred specific embodiment, be to wish to know more to describe feature of the present invention and spirit, and be not to come category of the present invention is limited with above-mentioned disclosed preferred specific embodiment.On the contrary, its objective is that hope can contain in the category of protection domain of being arranged in of various changes and tool equivalence institute of the present invention desire application.
Claims (8)
1. drive unit, be applicable in the flat-panel screens, this flat-panel screens comprises a display panel and at least two lamps, described lamp is used as the back light of this display panel, this drive unit comprises two transformers, each transformer has primary side and secondary side, then corresponding with one lamp of the secondary side of each transformer connects to light this lamp, wherein, first side winding polarity in this two transformer is identical, and has the secondary side winding coil of a transformer to rewind to form opposite polarity in this two transformer.
2. drive unit as claimed in claim 1, wherein utilize the secondary side winding coil back-roll that a transformer is arranged in this two transformer to form opposite polarity, make that the drive waveforms frequency that secondary side produced of this two transformer is identical and phase differential is maintained at 180 degree.
3. drive unit as claimed in claim 2, wherein this two transformer is required to be with a kind of type of drive.
4. drive unit as claimed in claim 3, wherein the radiometric reading of this low-frequency current field is 0.8V/m-0.3V/m.
5. drive unit as claimed in claim 1, wherein the secondary side of this two transformer produces identical and the drive waveforms that phase place is opposite of two frequencies, and described drive waveforms is offseted each other, in order to suppress the radiation of low-frequency current field.
6. drive unit as claimed in claim 1, wherein this lamp is a cold cathode ray tube.
7. drive unit as claimed in claim 1, wherein, the primary side of this two transformer is connected with a resonant circuit.
8. drive unit as claimed in claim 1, wherein, each is connected the primary side of this two transformer with a corresponding resonant circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03133158 CN1577460A (en) | 2003-07-29 | 2003-07-29 | Driver for planar Display |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03133158 CN1577460A (en) | 2003-07-29 | 2003-07-29 | Driver for planar Display |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1577460A true CN1577460A (en) | 2005-02-09 |
Family
ID=34579003
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 03133158 Pending CN1577460A (en) | 2003-07-29 | 2003-07-29 | Driver for planar Display |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1577460A (en) |
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2003
- 2003-07-29 CN CN 03133158 patent/CN1577460A/en active Pending
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| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
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