CN100559581C

CN100559581C - Luminous encapsulation, back light unit and the liquid crystal display device that comprises them

Info

Publication number: CN100559581C
Application number: CNB2006100872763A
Authority: CN
Inventors: 李昌昊; 安寅镐; 金富珍
Original assignee: LG Display Co Ltd
Current assignee: LG Display Co Ltd
Priority date: 2005-10-12
Filing date: 2006-06-14
Publication date: 2009-11-11
Anticipated expiration: 2026-06-14
Also published as: CN1949504A; KR20070040710A

Abstract

The invention discloses a kind of luminous encapsulation that can produce white light and can control red, green and blue light-emitting diode (LED) simultaneously.In this luminous encapsulation, a plurality of LED are connected in series with each other.These a plurality of LED are in response to a driving voltage.The electric current that flows through these a plurality of LED is controlled with current regulator.Thereby, the current drives that these a plurality of LED consumptions differ from one another.

Description

Luminous encapsulation, back light unit and the liquid crystal display device that comprises them

The application requires respectively on October 12nd, 2005 and on April 25th, 2006 rights and interests the korean patent application of Korea S Department of Intellectual Property submission 10-2005-0095880 number and 10-2006-0036995 number, and the disclosure of these applications is all quoted at this for referencial use.

Technical field

The present invention relates to a kind of light source that is used to emit white light, particularly relate to a kind of light source by using light-emitting diode to emit white light.And, the present invention relates to a kind of back light unit and liquid crystal display device that uses light-emitting diode.

Background technology

Liquid crystal display (LCD) device comes display image by the light transmission of control liquid crystal.This class LCD comprises the back light unit that face light is provided to liquid crystal panel, and described liquid crystal panel is each pixel region control light transmission.For uniform face light is provided to liquid crystal panel, back light unit comprises a plurality of light path control sheets that are used for luminous light source and are used for evenly distributing the light that sends.

Cold-cathode fluorescence lamp (CCFL) is widely used as the light source of back light unit.CCFL applies between two electrodes respect to one another electronics is sent from electrode.The electron excitation of sending is injected the into interior mercury of lamp, produces ultraviolet light.The phosphorus of the inner coating of uv light induction lamp, thus visible light sent from phosphorus.Fig. 1 illustrates the back light unit of the prior art of a kind of CCFL of employing.

With reference to Fig. 1, the back light unit of prior art comprises and is used for luminous a plurality of CCFL 1, is used for fixing and supports member 3 at the bottom of the lid of CCFL 1, and be arranged on

optical sheet

5a, 5b and 5c between CCFL 1 and the liquid crystal panel (not shown).

Optical sheet

5a, 5b and 5c have avoided light to project on the surface of liquid crystal panel with the form of CCFL 1, thereby uniform brightness is provided on the whole.In order to improve the scattering of light effect,

prismatic lens

5b and 5c and diffusion sheet 5a are set between CCFL 1 and liquid crystal panel.Being positioned at the reflecting plate 7 that covers on end member 3 inner surfaces will reflect towards liquid crystal panel from the light that CCFL 1 sends, thereby has improved the utilization of light.Two electrode (not shown) places at each CCFL 1 are provided with

electrode interconnection

9a and 9b respectively.The external voltage that is used to drive lamp provides via

electrode interconnection

9a and 9b.

The light source that such back light unit shows as image.Particularly, the light that sends from CCFL passes

optical sheet

5a, 5b and 5c, produces the white light of high brightness.By changing the arrangement of injecting the liquid crystal molecule in the feed liquor crystal panel, the liquid crystal panel that is located on the back light unit can be regulated light transmission.Simultaneously, by mix three primary colors (red (R), green (G) and blue (B)) with the colour filter (not shown), can show the full-colour image of expectation.In other words, pass R, G and B colour filter, can show desired images by making the light (white light) that sends from back light unit.

This back light unit is by the common CCFL 1 that uses, and

optical sheet

5a, 5b and 5c, and reflecting plate 7 can realize uniform luminance and high brightness.Yet this back light unit also is not suitable for large-scale LCD.Simultaneously, must apply high voltage to the anode of CCFL 1 sending electronics, thereby the heat that increases has reduced optical efficiency.In addition, also exist the toxic and grievous injury problem of environment of mercury.

Adopt the back light unit of the light-emitting diode (LED) that substitutes CCFL to have some advantage.As shown in Figure 2, the back light unit of prior art comprises the light source 11 with a plurality of R, G and B LED, is used for fixing member 13 at the bottom of the lid with supporting light sources 11, and is arranged on

optical sheet

15a, 15b and 15c between light source 11 and the liquid crystal panel (not shown).

Optical sheet

15a, 15b and 15c have avoided light to project on the surface of liquid crystal panel with the form of light source 11, thereby uniform luminance is provided on the whole.In order to improve the scattering of light effect,

prismatic lens

15b and 15c and diffusion sheet 15a are set between light source 11 and liquid crystal panel.On the inner surface of lid end member 13, reflecting plate 17 is set, will reflexes to liquid crystal panel from the light that light source 11 sends, thereby improve the utilization of light.Light source 11 comprises a plurality of luminous encapsulation 14 that is arranged in a line as shown in Figure 3.Each of these luminous encapsulation 14 all comprises a R LED 12a, two G LED 12b and a B LED 12c.

Usually, R LED 12a, the G LED 12b of luminous encapsulation 14 and B LED 12c control separately, because they have the device property that differs from one another.For example, can apply different voltage with 12c so that identical electric current flows through this each

LED

12a, 12b and 12c to each LED 12a, 12b.Even flow through identical electric current, but because the device property of each

LED

12a, 12b and 12c also can produce the light of different brightness.Therefore, in order to generate the white light with required white balance, the electric current that flows through R LED 12a, G LED12b, B LED 12c just is conditioned to such an extent that R LED 12a, G LED 12b, B LED 12c are controlled individually.

As shown in Figure 4, in a kind of device of prior art, R LED 12a, G LED 12b, B LED12c are driven individually.R LED 12a is provided with the voltage (Vin-R) that comes from R LED voltage generator 20a, produces the light of intensity corresponding to the electric current that flows through RLED 12a.G LED 12b is provided with the voltage (Vin-G) that comes from G LED voltage generator 20b, produces the light of intensity corresponding to the electric current that flows through G LED12b.B LED 12c is provided with the voltage (Vin-B) that comes from B LED voltage generator 20c, produces the light of intensity corresponding to the electric current that flows through B LED 12c.The light that produces from R LED 12a, G LED12b, B LED 12c incides the liquid crystal panel (not shown), shows desired images.

In this class back light unit, R LED 12a, G LED 12b, B LED 12c must be driven individually, have the white light of required white balance with generation.For this purpose, need provide R LED voltage generator 20a, G LED voltage generator 20b and B LED voltage generator 20c individually corresponding to RLED 12a, G LED 12b, B LED 12c.

Thereby it is complicated that the drive circuit of luminous encapsulation 14 just becomes, and manufacturing cost increases.

Summary of the invention

The present invention relates to luminous encapsulation, back light unit and the liquid crystal display device of implementing this luminous encapsulation and back light unit.

In one embodiment, a kind of luminous encapsulation comprises a plurality of light-emitting diodes (LED) that are connected in series and the current regulator that is coupled with these a plurality of LED.

In another embodiment, a kind of back light unit comprises a plurality of circuit boards and a plurality of luminous encapsulation that is arranged on each circuit board.This luminous encapsulation comprises a plurality of light-emitting diodes that are connected in series and the current regulator that is coupled with these a plurality of LED.

In another execution mode, a kind of liquid crystal display device comprises the back light unit with a plurality of circuit boards.This device also comprises a plurality of luminous encapsulation that is arranged on each circuit board.This luminous encapsulation comprises a plurality of light-emitting diodes that are connected in series and the current regulator that is coupled with these a plurality of LED.This liquid crystal display device also comprises liquid crystal panel, is used for coming display image by adjusting from the transmissivity of the white light of back light unit generation.

In another embodiment, a kind of luminous encapsulation comprises the voltage generator that is used to produce input voltage.In addition, this luminous encapsulation comprises and a plurality of light-emitting diodes (LED) of voltage generator coupling and the current regulator that is coupled with a plurality of LED.These LED in series arrange, and receive input voltage, and the current regulator control flows are crossed the electric current of these a plurality of LED.

Should be appreciated that top generality is described and following detailed all is schematic and indicative, being intended to provides further explanation to claim of the present invention.

Description of drawings

The included accompanying drawing of the application is used to provide to further understanding of the present invention, and is included in this application and as the application's a part, shows embodiments of the present invention and be used to explain principle of the present invention together with the description.

In the accompanying drawing:

Fig. 1 is the decomposition diagram of back light unit with prior art of CCFL;

Fig. 2 is the decomposition diagram of back light unit with prior art of R, G and B LED;

Fig. 3 is the view of the light source of prior art shown in Figure 2;

Fig. 4 is the circuit diagram that is used to drive the luminous encapsulation of LED of prior art shown in Figure 3;

Fig. 5 is the view according to a kind of LCD of execution mode;

Fig. 6 is the circuit diagram with luminous encapsulation of R, G and B LED;

Fig. 7 is the circuit diagram according to a kind of luminous encapsulation of execution mode;

Fig. 8 is the detailed circuit diagram according to the luminous encapsulation of this execution mode, is used for an embodiment of current regulator in the key diagram 7;

Fig. 9 is the detailed circuit diagram according to the luminous encapsulation of this execution mode, is used for another embodiment of current regulator in the key diagram 7;

Figure 10 is the detailed circuit diagram according to the luminous encapsulation of this execution mode, is used for another embodiment of current regulator in the key diagram 7;

Figure 11 is the circuit diagram according to the luminous encapsulation of another embodiment of the present invention.

Embodiment

Specifically describe preferred implementation of the present invention now, their embodiment is shown in the drawings.In any case institute's drawings attached uses the same reference numerals to represent identical or like.

Fig. 5 is the view according to LCD of the present invention (LCD).With reference to Fig. 5, comprise according to a kind of LCD of execution mode: liquid crystal panel 102, in this liquid crystal panel 102, be arranged with many grid line GL1 to GLn and many data wire DL1, DL2 to DLm, image is presented on this liquid crystal panel 102; Be used to drive the gate driver 104 and the data driver 106 of liquid crystal panel 102; The time schedule controller 108 that is used for control gate driver 104 and data driver 106; And be used to produce the back light unit 110 that will project the light on the liquid crystal panel 102.

In liquid crystal panel 102, be arranged with grid line GL1 to GLn and data wire DL1 to DLm, the thin-film transistor (TFT) that is used as switch element is arranged in the zone that limits thus.TFT has the grid that is electrically connected on the grid line GL1 to GLn, is electrically connected to the source electrode of data wire DL1 to DLm, and the drain electrode that is electrically connected to the pixel electrode (not shown).

TFT is ending when grid low-voltage (VGL) is provided when providing sweep signal conducting when (particularly, grid high voltage (VGH)) to grid line GL1 to GLn.Simultaneously, when the TFT conducting, the data voltage on the data wire passes source electrode and the drain electrode of TFT, is provided to pixel electrode.Data voltage remains on the pixel electrode place, provides grid high voltage (VGH) up to next frame.

Gate driver 104 provides sweep signal (grid high voltage (VGH) particularly) in response to the grid-control system signal that produces from time schedule controller 108 to grid line GL1 to GLn.

Data driver 106 is in response to the data controlling signal that produces from time schedule controller 108, and DL1 to DLm provides data voltage to data wire.Simultaneously, data driver 106 R, G, the B data-signal that will come from time schedule controller 108 converts analog data voltage to.

By vertical/horizontal synchronizing signal (Vsync/Hsync), data enable signal DE and the clock signal (all not shown) that provides from external system is provided, time schedule controller 108 produces grid control signal that is used for control gate driver 104 and the data controlling signal that is used for control data driver 106.Simultaneously, time schedule controller 108 makes R, G become a line with the B data arrangement, then they is provided to data driver 106.R, G and B data provide from this system with the form of unit frame.

Back light unit 110 produces the light that will shine on the liquid crystal panel 102.The generation of this light is controlled by the control signal that is produced by time schedule controller 108.Back light unit 110 comprises a plurality of optical sheets, reflecting plate and light source.And the light source of back light unit 110 comprises the luminous encapsulation of a plurality of R of having, G, B LED and produces the LED voltage generator of the driving voltage be used to drive R, G, B LED.Preferably, the R of luminous encapsulation, G and B LED are luminous in response to the individual drive voltage that produces from the LED voltage generator jointly.Be connected to the light source that luminous encapsulation 112 on the LED voltage generator 120 can be considered to have the luminous encapsulation that can drive in response to individual drive voltage.

With reference to Fig. 6, luminous encapsulation 112 comprises R LED 112a, G LED 112b and the BLED 112c that is connected in series.The input voltage vin that produces from LED voltage generator 120 is provided on the series circuit of the RLED 112a, the G LED 112b that are connected in series and B LED 112c.Because the existence of R LED 112a, it is so much that the input voltage vin that produces from LED voltage generator 120 at first is reduced the driving voltage V (R) of R LED 112a.The voltage Vin-V (R) that has at first been reduced is provided on the series circuit of G LED 112b and BLED 112c again.Because the existence of G LED 112b, it is so much that secondly the voltage Vin-V (R) that has at first been reduced is reduced driving voltage V (G).Be provided to again on the B LED 112c by next voltage Vin-V (R)-V (G) that has reduced.Thereby the voltage of different stage is provided on RLED 112a, G LED 112b and the B LED 112c.On the contrary, because R LED is 112a, G LED 112b and B LED 112c are connected in series, so what flow through them is the electric current of same amount.

Even the voltage that provides when identical electric current is provided to R LED 112a, G LED 112b and B LED 112c also is different, so R LED 112a, G LED 112b show different device properties with B LED 112c.The device property of R LED 112a, G LED 112b and B LED 112c can be found out from following table 1.Table 1 illustrates the device property of R LED 112a, G LED 112b and BLED 112c with electric current, voltage and power.

[table 1]

As can be seen from Table 1, suppose that identical electric current flows through R LED 112a, G LED 112b and B LED112c, then different voltage V is provided to R LED 112a, G LED 112b and B LED 112c.For example, for the electric current that makes 50mA flows through R LED 112a, G LED 112b and B LED 112c, must be respectively provide the voltage of 1.92V, 2.69V and 2.91V to R LED 112a, G LED 112b and B LED 112c.

Even provide the electric current of same amount to R LED 112a, G LED 112b and B LED 112c, the amount of the light that is sent by RLED 112a, G LED 112b and B LED 112c also is different.In other words, even the R LED 112a, the G LED 112b that are connected in series and the B LED 112c current drives of same amount, they also have different brightness.Therefore, the RLED 112a that is connected in series, G LED 112b and B LED 112c can not send required white light.So, in order to send required white light, just individual drive R LED 112a, G LED 112b and B LED 112c as shown in Figure 4.

Fig. 7 is the view that comprises according to the light source of the back light unit of the luminous encapsulation of one embodiment of the present invention.With reference to Fig. 7, the light source of this back light unit comprises the luminous encapsulation 130 that is connected on the LED voltage generator 120.Luminous encapsulation 130 comprises LED series circuit 200, and it is in response to the input voltage vin that produces from LED voltage generator 120.LED series circuit 200 is included in R LED LDr, G LED LDg and the B LEDLDb that is connected in series between the output of LED voltage generator 120 and the earth terminal GND.Be connected in series R LED LDr, G LED LDg on the LED voltage generator 120 and BLED LDb jointly in response to the input voltage vin that produces from LED voltage generator 120.Simultaneously, R LEDLDr, G LED LDg and B LED LDb send corresponding to the light that applies the magnitude of current thereon.

Luminous encapsulation 130 comprises current regulator 210, and it is used to regulate the amount of the electric current of the R LED LDr, the G LED LDg that flow through LED series circuit 200 respectively and B LED LDb.Current regulator 210 can manufacture the individual module integrated with LED series circuit 200, perhaps can separate manufacturing with LED series circuit 200.The amount that current regulator 210 is regulated each electric current that flows through R LED LDr, G LED LDg and B LED LDb is with R, G and the B light that sends white light.

Because the amount that flows through the electric current of R LED LDr, G LED LDg and B LED LDb is regulated distinctively by current regulator 210, so R LED LDr, G LED LDg and B LED LDb can send R light, G light and B light, thereby form required white light.Simultaneously, R LED LDr, the G LEDLDg and the B LED LDb that are connected in series send R light, G light and B light in response to input voltage vin jointly.

Therefore, different with the prior art that adopts a plurality of LED voltage generators, a LED voltage generator is only adopted in this luminous encapsulation, thereby has simplified the adjunct circuit of the controller that for example is used to control the LED voltage generator.In addition, luminous encapsulation of the present invention can reduce the manufacturing cost of LCD and back light unit.In addition, manufacture process also can be simplified, and the volume of the light source of back light unit also can reduce.

Fig. 8 is the circuit diagram according to the luminous encapsulation of one embodiment of the present invention, is used for an embodiment of key diagram 7 current regulators 210.The current regulator 210 of luminous encapsulation 130 comprises that the R LED LDr, the G LED LDg that are parallel-connected to LED series circuit 200 and first to the 3rd resistance R 1 on the B LED LDb are to R3.Particularly, first resistance R 1 is parallel-connected on the R LED LDr, and second resistance R 2 is parallel-connected on the G LED LDg, and the 3rd resistance R 3 is parallel-connected on the B LED LDb.

Flowing through the R LED LDr, the G LED LDg that are parallel-connected on first to the 3rd resistance R 1 to R3 and electric current I r, Ig and the Ib of B LED LDb can differ from one another because a part circuitous (bypass) that flows through electric current I r, the Ig of R LED LDr, G LEDLDg and B LED LDb and Ib by resistance R 1 to R3.Therefore, first to the 3rd resistance R 1 to R3 can change electric current I r, Ig and the Ib that flows through R LED LDr, G LED LDg and B LED LDb, so that R LED LDr, G LED LDg and B LED LDb send R, G and B light forms white light.In other words, can provide different electric currents to R LED LDr, G LED LDg with B LED LDb, so that R LED LDr, G LED LDg and B LED LDb send the light (that is same brightness) of same amount by first to the 3rd resistance R 1 to R3.

So that R LED LDr, G LED LDg and B LED LDb can send required white light, first to the 3rd R1 to R3 should have different resistance in order to send R, G and B light.In this case, different electric currents flow through R LED LDr, G LED LDg and the B LED LDb that is parallel-connected on first to the 3rd R1 to R3.Particularly, the electric current I r that flows through R LED LDr is different from electric current I g and the current Ib that flows through G LED LDg and B LED LDb.As mentioned above, R LED LDr, the G LED LDg of LED parallel circuits 200 and B LED LDb are luminous according to the magnitude of current (that is brightness) that flows through wherein.

Each resistance of first to the 3rd resistance R 1 to R3 becomes to have certain ratio according to the different set of device property, so that R LED LDr, G LED LDg can send identical brightness with B LED LDb.For example, the brightness of supposing R LED LDr is 100, and the brightness of G LED LDg is 150, and the brightness of B LED LDb is 200, and need have the white light of their combined brightness.So, the ratio of the resistance of first to the 3rd resistance R 1 to R3 should increase along with from first to the 3rd resistance R 1 to R3.

Simultaneously, the resistance of first to the 3rd resistance R 1 to R3 is also set according to the ratio based on the balance of R, G and B light.For example, suppose that formation white light requirement R LED LDr has 100 brightness, G LEDLDg has 150 brightness, and B LED LDb has 200 brightness.

So, the resistance ratio of first to the 3rd resistance R 1 to R3 is set to along with from first to the 3rd resistance R 1 to R3 and reduces.

Similarly, the resistance of first to the 3rd resistance R 1 to R3 is set for according to the difference of the character of R LED LDr, G LED LDg and B LED LDb and the white balance that forms white light and is had suitable ratio.Resistance ratio satisfies the nature difference of R LED LDr, G LED LDg and B LED LDb and first to the 3rd R1 to R3 of white balance is connected on R LED LDr, G LED LDg and the B LED LDb in parallel.Therefore, in response to the input voltage vin that produces from LED voltage generator 120, R LED LDr, GLED LDg and B LED LDb can send R, G, the B light that forms white light by jointly.

Fig. 9 is the circuit diagram according to the luminous encapsulation of another embodiment of the present invention, is used for another embodiment of current regulator 210 in the key diagram 7.The current regulator 210 of luminous encapsulation 130 comprises that being loop shape is parallel-connected to first to the 3rd resistance R 1 on the LED series circuit 200 to R3, and the overlapping of these loops (overlapping) length shortens gradually.First resistance R 1 is parallel-connected on the series circuit of R LED LDr, G LED LDg and B LED LDb, and second resistance R 2 is parallel-connected on the series circuit of G LED LDg and B LED LDb, and the 3rd resistance R 3 is parallel-connected to separately on the B LED LDb.In other words, B LED LDb forms triple parallel circuitss together with first to the 3rd resistance R 1 to R3, and GLED LDg forms dual parallel circuits together with first and second resistance R 1 and R2, and R LED LDr forms a parallel circuits together with first resistance R 1.

Current regulator 210 have be parallel-connected on the LED series circuit 200, form the loop that overlapping length shortens gradually first to the 3rd resistance R 1 to R3, this current regulator 210 can be regulated the amount of the electric current that is provided to R LED LDr, G LED LDg and B LED LDb step by step according to the difference and the white balance of device property.In this case, R LED LDr, G LED LDg and B LED LDb couple together, and form multiple parallel circuits together with first to the 3rd R1 to R3.

The device property of supposing R LED LDr is poorer than the device property of G LED LDg and B LED LD, and the device property of G LED LDg is poorer than the device property of B LED LD, and the type of attachment of first to the 3rd resistance R 1 to R3 and LED series circuit 200 can have current regulator shown in Figure 9 210 among Fig. 9 so.The arrangement of R LED LDr, G LED LDg and B LED LDb can change according to they character separately.Thereby to those skilled in the art, obviously, the position of R LED LDr, G LEDLDg and B LED LDb also can change.

In these resistance of current regulator 210, first resistance R 1 is adjusted to the amount of suitably setting the electric current I r that flows through R LED LDr.Simultaneously, the resistance of first resistance R 1 also can be adjusted to the amount of suitably setting the electric current that flows through LED series circuit 200.The resistance of second resistance R 2 is adjusted to suitably to be set the amount that flows through the electric current I g of G LED LDg within the specific limits, and the amount of electric current I g is less than the amount of the electric current I r that flows through RLED LDr.The resistance of the 3rd resistance R 3 can be adjusted to suitably to be set the amount that flows through the current Ib of B LED LDb within the specific limits, and the amount of current Ib is less than the amount of the electric current I g that flows through G LED LDg.

Adopt first to the 3rd resistance R 1 to R3, electric current I r, the Ig and the Ib that flow through R LED LDr, G LED LDg and B LEDLDb can reduce gradually, with the difference that satisfies device property and required white balance.Thereby R LED LDr, G LED LDg and B LED LDb in response to the input voltage vin that produces from LED voltage generator 120, send R, G and B light by jointly, form white light.

Thereby luminous encapsulation of the present invention can be regulated white balance based on R, G, B light at an easy rate by means of Current Regulation step by step.Therefore, different with the prior art that adopts a plurality of LED voltage generators, a LED voltage generator is only adopted in this luminous encapsulation, thereby has simplified the adjunct circuit of the controller that for example is used to control the LED voltage generator.In addition, luminous encapsulation of the present invention can reduce the manufacturing cost of LCD and back light unit.In addition, manufacture process also can be simplified, and the volume of the light source of back light unit also can reduce.

Figure 10 is the circuit diagram according to the luminous encapsulation of one embodiment of the present invention, is used for another embodiment of current regulator 210 of key diagram 7.The current regulator 210 of luminous encapsulation 130 comprises that one is included in R LED LDr, G LED LDg in the LED series circuit 200 and the series circuit of B LED LDb, and is parallel-connected to first, second and the 3rd resistance R 1, R2 and R3 on R LED LDr, G LED LDg and the B LED LDb respectively.That is, R LED LDr forms dual parallel circuits with first and second resistance R 1 and R2.B LED LDb forms dual parallel circuits with the first and the 3rd resistance R 1 and R3.Simultaneously, G LED LDg forms a parallel circuits with first resistance R 1 separately.

The resistance of first resistance R 1 is conditioned the amount of crossing the electric current of G LED LDg with control flows.Be adjusted to well under the state that does not have G LED LDg and also can be formed required white light if flow through the electric current I g of G LED LDg, can not comprised first resistance R 1 so in this embodiment.The resistance of second resistance R 2 is conditioned and makes the amount of the electric current I r flow through R LED LDr less than the amount of the electric current I g that flows through G LED LDg.Similarly, the resistance of the 3rd resistance R 3 is conditioned and makes the amount of the current Ib flow through B LED LDb less than the amount of the electric current I g that flows through G LED LDg.

By this way, each the amount of the electric current I r of R LED LDr and B LED LDb and Ib that flows through is all regulated according to the amount that flows through the electric current I g of G LED LDg, and this is because green glow can appreciable impact brightness.Based on this, consider the difference of device property and required white balance, the resistance of first resistance R 1 can be adjusted to the amount of suitably setting the electric current I g that flows through G LED LDg and the brightness that improves G LED LDg.After the amount of the electric current I g that flows through G LED LDg was conditioned, the resistance of the second and the 3rd resistance R 2 and R3 was conditioned and makes the amount of the electric current I r flow through R LED LDr and B LED LDb and Ib less than the amount of the electric current I g that flows through G LED LDg.Thereby R LED LDr, G LED LDg and B LED LDb in response to the input voltage vin that produces from LED voltage generator 120, send R, G and B light by jointly, form white light.

Therefore, luminous encapsulation of the present invention can be sent required white light.Thereby different with the prior art that adopts a plurality of LED voltage generators, a LED voltage generator is only adopted in this luminous encapsulation, thereby has simplified the adjunct circuit of the controller that for example is used to control the LED voltage generator.In addition, luminous encapsulation of the present invention can reduce the manufacturing cost of LCD and back light unit.In addition, manufacture process also can be simplified, and the volume of the light source of back light unit also can reduce.

Figure 11 is the luminous encapsulation 130 according to another embodiment of the present invention.With reference to Figure 11, luminous encapsulation 130 is except that being provided with on the LED series circuit 200 the LED lens 220, and is substantially the same in the luminous encapsulation of Fig. 7.In Figure 11,, therefore omitted their detailed description for brevity because identical Reference numeral and symbol is used to refer to the same or analogous parts with Fig. 7.

LED series circuit 200 comprises R LED LDr, G LED LDg and B LED LDb, and they are jointly in response to the input voltage vin that produces from LED voltage generator 120.To those skilled in the art, obviously, can adopt mode identical as Fig. 8 to 10, flow through the amount of the electric current of R LED LDr, G LED LDg and B LED LDb with current regulator 210 adjustings.

LED lens 220 can provide by assembling and mix the white light that the R, the G that send from R LEDLDr, G LED LDg and the B LED LDb of LED series circuit 200 and B light are realized.Simultaneously, LED lens 220 can protective current adjusters 210 and are had R LED LDr, G LED LDg and the LED series circuit 200 of B LED LDb is avoided outside impact.In addition, LED lens 220 can also avoid R LED LDr, G LED LDg and B LED LDb to be subjected to the pollution of impurity.

LED lens 220 can be different with current regulator 210 integrally formed structures therewith with LED series circuit 200, and LED lens 220 also can be integrally formed with the LED series circuit 200 except that current regulator 210.

As mentioned above, flow through R LED, G LED and the B LED of luminous encapsulation by making different electric currents, these LED can send R, G and B light in response to signal voltage Vin jointly, form white light.Thereby different with the prior art that adopts a plurality of LED voltage generators, a LED voltage generator is only adopted in this luminous encapsulation, thereby has simplified the adjunct circuit of the controller that for example is used to control the LED voltage generator.In addition, luminous encapsulation of the present invention can reduce the manufacturing cost of LCD and back light unit.In addition, manufacture process also can be simplified, and the volume of the light source of back light unit also can reduce.

Clearly, those skilled in the art can make modifications and variations to the present invention on the basis that does not deviate from the spirit or scope of the present invention.Therefore, this invention is intended to cover the various modifications and variations that fall in claim of the present invention and the equivalent scope thereof.

Claims

1. luminous encapsulation comprises:

The a plurality of light-emitting diodes that are connected in series; And

Be parallel-connected to a plurality of resistance on described a plurality of light-emitting diode,

Wherein, a plurality of light-emitting diodes comprise red light emitting diodes, green LED and blue LED, and a plurality of resistance comprises first resistance, second resistance and the 3rd resistance,

Wherein, first resistance is parallel-connected to red light emitting diodes, and second resistance is parallel-connected to green LED, and the 3rd resistance is parallel-connected to blue LED, and

Wherein, in order to obtain white light, be required to have the brightness bigger than green LED at blue LED, when green LED was required to have than the bigger brightness of red light emitting diodes, the resistance ratio of first to the 3rd resistance was along with reducing from first resistance to the, three resistance.

2. luminous encapsulation according to claim 1 is characterized in that, each resistance in described a plurality of resistance has different resistances from each other, to establish white balance.

3. luminous encapsulation according to claim 1 is characterized in that, described first resistance, and the ratio of the resistance value of second resistance and the 3rd resistance is set to be guaranteed from Red LED1, the amount of the light that green light-emitting diode and blue light-emitting diode send equates.

4. luminous encapsulation according to claim 1 is characterized in that, the resistance value that each resistance in described a plurality of resistance has is set relevant one electric current crossing a plurality of light-emitting diodes with control flows.

5. luminous encapsulation according to claim 1 is characterized in that, described resistance value is defined so that the amount of the light that sends from each light-emitting diode equates.

6. luminous encapsulation according to claim 1 is characterized in that, also comprises the lens that are arranged on described a plurality of light-emitting diode.

7. luminous encapsulation comprises: a plurality of light-emitting diodes that are connected in series; And

Wherein, first resistance is parallel-connected to red light emitting diodes, green LED and blue LED, and second resistance is parallel-connected to green LED and blue LED, and the 3rd resistance is parallel-connected to blue LED, and

8. luminous encapsulation comprises:

The a plurality of light-emitting diodes that are connected in series; And

Wherein, red light emitting diodes forms dual parallel circuits with first and second resistance, and blue LED forms dual parallel circuits with the first and the 3rd resistance, and green LED forms parallel circuits with first resistance separately, and

Wherein, the resistance value of first resistance is conditioned and makes the magnitude of current that flows through red light emitting diodes, green LED and blue LED be equal to the magnitude of current that flows through green LED, the resistance value of second resistance is conditioned and makes the magnitude of current flow through red light emitting diodes less than the magnitude of current that flows through green LED, and the resistance value of the 3rd resistance is conditioned and makes and flow through the magnitude of current of blue LED less than the magnitude of current that flows through green LED.

9. back light unit comprises:

A plurality of circuit boards; And

Be arranged on a plurality of luminous encapsulation on described a plurality of circuit board, described a plurality of luminous encapsulation comprise a plurality of light-emitting diodes that are connected in series and a plurality of resistance that are parallel-connected on described a plurality of light-emitting diode,

10. liquid crystal display device comprises:

Back light unit comprises:

A plurality of circuit boards;

Be arranged on a plurality of luminous encapsulation on described a plurality of circuit board, described a plurality of luminous encapsulation comprise a plurality of light-emitting diodes that are connected in series and a plurality of resistance that are parallel-connected on described a plurality of light-emitting diode; And

Liquid crystal panel, it is used for the light display image that sends from described back light unit by utilizing,

11. a back light unit comprises:

Be used to produce the voltage generator of input voltage;

With a plurality of light-emitting diodes of described voltage generator coupling, wherein said light-emitting diode series connection ground is provided with, and receives described input voltage; And