CN100416350C - Backlight driving device, backlight driving method, and liquid crystal display device - Google Patents
Backlight driving device, backlight driving method, and liquid crystal display device Download PDFInfo
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- CN100416350C CN100416350C CNB2005101237049A CN200510123704A CN100416350C CN 100416350 C CN100416350 C CN 100416350C CN B2005101237049 A CNB2005101237049 A CN B2005101237049A CN 200510123704 A CN200510123704 A CN 200510123704A CN 100416350 C CN100416350 C CN 100416350C
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Abstract
The invention discloses a backlighting drive device, which is used for controlling the driving of a backlighting device used on a display, wherein, the backlighting device generates preconcerted white light through mixing the light emitted from a plurality of LBDs with three or more colors. The backlighting drive device comprises a memory device which is used for memorizing initial amperage and preconcerted multiplication constant of each color; a luminous flux detection device used for detecting the luminous flux of each color; and a control device which is used for taking the amperage obtained through multiplying the initial amperage by the preconcerted multiplication constant as a starting value, and adjusting the amperage flowing through each different color LBD to generate the preconcerted white light through feedback control based on detection output of the luminous flux detection device, wherein, when the difference value between the amperage and the initial amperage after the feedback control is more than a preconcerted threshold value, the control device renews the multiplication constant according to the amperage after the feedback control.
Description
The cross reference of related application
Japanese patent application 2004-336571 number that the theme that the present invention includes relates on November 19th, 2004 to be submitted to Jap.P. office and on August 25th, 2005, its full content was hereby expressly incorporated by reference to the Japanese patent application of Jap.P. office submission 2005-244924 number.
Technical field
The present invention relates to (backlight) backlight drive unit, backlight driving method and be used for the liquid crystal indicator of driving that control comprises the back lighting device of LED (light emitting diode) element.
Background technology
Although adopting the backlight of CCFL (cold-cathode fluorescence lamp) type of fluorescent tube is the main flow of liquid crystal board back light, consider environmental factor, to the not mercurous demand that has backlight always.Just because of this, people have thought that LED is expected to become the light source that replaces CCFL recently.The primary colors of a kind of independent use red LED, green LED, blue led also adds the method that the mixture of colours obtains white light by optics is synthetic, and especially, it is considered to be particularly advantageous in and is used for the TV purpose, and reason is that this method is convenient to obtain colour balance.
When LED was used as light source backlight, the luminescence efficiency of red LED, green LED and blue led was different, and the electric current that therefore flows through the LED of every kind of color should be irrelevant with other color.Form element (element) voltage difference different, that be used for every kind of color because be used for the semiconductor of the LED of every kind of color, so the power consumption of every kind of color is also different.Equally, when LED is used as back light, consider, can not drive each LED (seeing that Jap.P. discloses 2001-272938 number) respectively from the angle of actual cost.
Therefore, when LED is used as light source backlight, adopt the LED (being connected in series) of cascade some and the method for whole driving LED.
Especially, adopt a kind of method, wherein, be cascaded series as each LED of load, for example, be used for each cascaded series of predetermined quantity LED of every kind of color of redness, green, blueness, DC-DC converter power and PWM (width modulation) are provided control module.Red, green, the blue versicolor luminous flux of light sensors, and based on testing result, by FEEDBACK CONTROL, the magnitude of current that flows through every group of LED is carried out PWM regulate, thereby regulate by red, green, blue synthetic colourity that obtains and brightness.
Summary of the invention
Yet, if the response of such FEEDBACK CONTROL is very fast, the colourity frequent variations, this is easy to visually be perceiveed out by the user.For fear of the inconvenience that colourity frequent variations like this is brought, the response with FEEDBACK CONTROL is provided with very lowly usually.Therefore can not expect to regulate colourity during energized by such FEEDBACK CONTROL.
Like this, have such LED, for example, be initially every kind of color before dispatching from the factory and be provided as reference power (power) amount that obtains predetermined white light as in light source backlight.For example, by dutycycle and peak value (flowing through the constant current value of every group of LED) are set roughly for the LED of every kind of color, make this dutycycle and peak value adjustable and adjusting dutycycle and peak value, so that obtain the luminous flux of expectation and the colourity of expectation, and the output of the optical sensor of dutycycle, the every kind of color of the LED of every kind of color of storage and the output of temperature sensor in nonvolatile memory, carry out such initial setting up.
Like this, because set in advance, so can obtain predetermined white light by read this dutycycle from nonvolatile memory during energized with dutycycle for referencial use.
Yet LED is that brightness weakens the device of (degrade) in time.In addition, weaken speed and not only change between the LED of different colours, and change between the LED of same color, this depends on the variation when making, the temperature of LED, environment temperature of placing environment backlight etc.
Therefore, when brightness weakened greatly, the dutycycle of reading above-mentioned reference value and the LED by regulating two kinds of colors from nonvolatile memory after the energized obtained the predetermined required time (convergence time, converging time) of white light and is extended.As a result, for example, screen is little red phenomenon that bleaches gradually afterwards when energized occurring.In addition, when making the dutycycle increase of LED owing to brightness deterioration, power consumption backlight is compared increase with initial setting up phenomenon appears.
Incidentally, not only under the situation that above-mentioned brightness weakens in time, can cause this problem, and the dutycycle the when changing features of the LED that causes owing to reason such as annealing deficiency etc. and initial setting up and regulate after dutycycle between difference also can cause this problem when becoming very big.
Consider that so traditional actual conditions have proposed the present invention, expectation provides a kind of backlight drive device, backlight driving method and liquid crystal indicator, it can prevent when obtaining to be scheduled to white light by the magnitude of current that flows through LED with the FEEDBACK CONTROL adjusting, because the prolongation of the convergence colourity required time that factors such as secular variation cause.
According to one embodiment of present invention, a kind of backlight drive device that is used to control the driving of the back lighting device that is used for display is provided, back lighting device is by mixing from the light of a plurality of light emitting diodes of three kinds or more colors, generate predetermined white light, this backlight drive device comprises: memory storage is used to store the initial current amount and the predetermined multiplication constant of every kind of color; The luminous flux detection device is used to detect the luminous flux of every kind of color; And control device, be used for initial current amount and predetermined multiplication constant are multiplied each other the magnitude of current that obtains as initial value,, pass through FEEDBACK CONTROL based on the output of luminous flux detection Device Testing, the magnitude of current of the light emitting diode of every kind of color is flow through in adjusting, generates predetermined white light thus; Wherein, when the magnitude of current after the FEEDBACK CONTROL and the difference between the initial current amount surpassed predetermined threshold, this control device upgraded multiplication constant according to the magnitude of current after the FEEDBACK CONTROL.
In addition, according to one embodiment of present invention, a kind of backlight driving method that is used to control the driving of the back lighting device that is used for display is provided, back lighting device is by mixing from the light of a plurality of light emitting diodes of three kinds or more colors, generate predetermined white light, this backlight driving method comprises: read step is used for being read as initial current amount and the predetermined multiplication constant that every kind of color is stored from memory storage; The luminous flux detection step is used to detect the luminous flux of every kind of color; Controlled step, be used for initial current amount and predetermined multiplication constant are multiplied each other the magnitude of current that obtains as initial value,, pass through FEEDBACK CONTROL based on the detection output of luminous flux detection step, the magnitude of current of the light emitting diode of every kind of color is flow through in adjusting, generates predetermined white light thus; And step of updating, when being used for the magnitude of current after the FEEDBACK CONTROL and the difference between the initial current amount and surpassing predetermined threshold, upgrade multiplication constant according to the magnitude of current after the FEEDBACK CONTROL.
In addition, according to one embodiment of present invention, provide a kind of liquid crystal indicator, comprise: back lighting device, be used for generating predetermined white light by mixing from the light of a plurality of light emitting diodes of three kinds or more colors, this back lighting device is driven by backlight drive device; And the transmission type colour liquid crystal display board, quilt is from the white light of the back lighting device generation of this transmission type colour liquid crystal displaying plate face; Wherein, backlight drive device comprises: memory storage is used to store the initial current amount and the predetermined multiplication constant of every kind of color; The luminous flux detection device is used to detect the luminous flux of every kind of color; And control device, be used for initial current amount and predetermined multiplication constant are multiplied each other the magnitude of current that obtains as initial value, export based on the luminous flux detection Device Testing, pass through FEEDBACK CONTROL, the magnitude of current of the light emitting diode of every kind of color is flow through in adjusting, generate predetermined white light thus, and when the magnitude of current after the FEEDBACK CONTROL and the difference between the initial current amount surpassed predetermined threshold, this control device was according to the renewal of the magnitude of current after FEEDBACK CONTROL multiplication constant.
According to the present invention, the initial current amount that will store in memory storage and predetermined multiplication constant multiply each other the magnitude of current that obtains as initial value, regulate the magnitude of current of the light emitting diode that flows through every kind of color by FEEDBACK CONTROL, generate predetermined white light thus.More particularly, when the magnitude of current after the FEEDBACK CONTROL and the difference between the initial current amount surpass predetermined threshold, upgrade multiplication constant according to the magnitude of current after the FEEDBACK CONTROL.Therefore, even when causing light-emitting diode luminance to weaken, can prevent to assemble the prolongation of colourity required time owing to factors such as secular variation.
Description of drawings
Fig. 1 is the perspective schematic view of structure of using the backlight type liquid crystal display of color liquid crystal display arrangement of the present invention;
Fig. 2 is the synoptic diagram of unit cell, wherein, use two red light emitting diodes, two green LEDs and two blue LEDs, and six light emitting diodes all are in line the number of the light emitting diode of the corresponding every kind of color of pattern symbol;
Fig. 3 is the synoptic diagram of example that forms the connection of the actual leds in the light source of back lighting device of color liquid crystal display arrangement;
Fig. 4 is the block scheme of example of the universal architecture of color liquid crystal display arrangement;
Fig. 5 is the temperature sensor that is provided with in the back lighting device and the synoptic diagram of luminous flux or chromaticity transducer;
Fig. 6 is the synoptic diagram that is used for the backlight drive control module of driven for emitting lights diode; And
Fig. 7 is the process flow diagram of the processing of microcomputer in the supplementary explanation backlight drive control module.
Embodiment
Hereinafter will be described in detail with reference to the attached drawings and use a specific embodiment of the present invention.
For example, the present invention is applied to have the color liquid crystal display arrangement of the backlight type liquid crystal display 1 that forms as shown in Figure 1.
Liquid crystal display 1 comprises transmission type colour liquid crystal display board 10 and is positioned at the back lighting device 20 at color LCD board 10 back sides.
Transmission type colour liquid crystal display board 10 is to form like this, promptly, by arranging TFT substrate 11 and counter electrode substrate 12, make that TFT substrate 11 and counter electrode substrate 12 are staggered relatively, and provide by being filled into the liquid crystal layer 13 that forms in the gap between TFT substrate 11 and the counter electrode substrate 12 such as twisted nematic (TN) liquid crystal.On TFT substrate 11, be formed with: the signal wire 14, the sweep trace 15 that become arranged in matrix; Thin film transistor (TFT) 16 is arranged on the point of crossing between signal wire 14 and the sweep trace 15 as on-off element; And pixel electrode 17.Thin film transistor (TFT) 16 is scanned line 15 and sequentially selects, and the vision signal that signal wire 14 provides is write corresponding pixel electrode 17.Counter electrode 18 and color filter 19 are formed on the inside surface of counter electrode substrate 12.
In the color liquid crystal display unit 1, so the transmission type colour liquid crystal display board 10 that forms places between two polaroids.Color liquid crystal display unit 1 drives transmission type colour liquid crystal display board 10 in the active matrix mode, provides the panchromatic video of expectation to show, wherein transmission type colour liquid crystal display board 10 by back lighting device 20 from its back side illuminaton white light.
The light source 21 of back lighting device 20 comprises a large amount of light emitting diodes (LED:LightEmitting Diode) 3.The light of light source 21 output light emitting diodes emission.Light source 21 comprises the light emitting diode 3R of a large amount of emissions red (R) light, launches light emitting diode 3G of green (G) light and the light emitting diode 3B of blue (B) light of a large amount of emissions in a large number.Light source 21 passes through R, G and B light are mixed the generation white light, and this white light emission is arrived color LCD board 10.
For example, the arrangement of the light emitting diode 3 in the light source 21 of back lighting device 20 is as follows.
At first, as shown in Figure 2, use two red light emitting diodes 3R, two green LED 3G and two blue LED 3B, and six light emitting diodes are arranged in all in the delegation as unit cell ( 2G 2R 2B).Next, by further arranging three unit cells in the horizontal direction, form intermediate unit ( 6G 6R 6B).Then, as shown in Figure 3, such intermediate unit ( 6G 6R 6B) connection that is one another in series in the horizontal direction, and arrange the light emitting diode 3 that is connected in series each other in vertical direction, to cover whole screen.
By arranging light emitting diode 3 like this, three kinds of color R, G and the B of light emitting diode mix mutually, launch well-balanced white light.Incidentally, the arrangement of light emitting diode 3 is not limited to Fig. 2 and arrangement shown in Figure 3, as long as color is mixed mutually in well-balanced mode, any arrangement all allows.Light emitting diode 3 is not limited to the light emitting diode of R, G and three kinds of colors of B, also can adopt the light emitting diode of more colors to generate the white light of predetermined chromaticity.
Fig. 4 shows the example of the universal architecture of color liquid crystal display arrangement 30.
Color liquid crystal display arrangement 30 comprises: power supply unit 31 is used to provide the electric energy that drives color LCD board 10 and back lighting device 20; X-drive circuit 32 and Y-drive circuit 33 are used to drive color LCD board 10; RGB process control unit 35 provides vision signal from the outside to it by input terminal 34; Video memory 36 and control module 37 are connected to RGB process control unit 35; And backlight drive control module 38, be used for the drive controlling of back lighting device 20.
Carry out signal Processing by 35 pairs of RGB process processing element via the vision signals of input terminal 34 inputs, and further convert the vision signal of input to be fit to drive color LCD board 10 RGB separation signal from composite signal such as colourity processing etc.The RGB separation signal is provided for control module 37, also is provided for X-driver 32 by video memory 36.Control module 37 is according to the RGB separation signal, at predetermined timing controlled X-drive circuit 32 and Y-drive circuit 33, and use the RGB separation signal driving color LCD board 10 that offers X-driver 32 via video memory 36, show the video corresponding thus with the RGB separation signal.
As shown in Figure 4 and Figure 5, color liquid crystal display arrangement 30 comprises: temperature sensor 41 is used to detect the temperature of the light source 21 (light emitting diode) of back lighting device 20; Luminous flux or chromaticity transducer 42 (42R, 42G and 42B) are used for detecting in R, the G of the light source 21 (light emitting diode) of back lighting device 20 and the luminous flux or the colourity of B color.
The detected value of the detected value of temperature sensor 41 and luminous flux or chromaticity transducer 42 is provided for backlight drive control module 38.Backlight drive control module 38 is based on the detected value of these sensors, and control is used to drive the drive current of the light emitting diode that forms light source 21.
Next use description to drive the backlight drive control module 38 of the light emitting diode 3 that is connected in series mutually in the horizontal direction.Fig. 6 shows the example of the circuit structure of backlight drive control module 38.
Backlight drive control module 38 comprises DC-DC converter 51, constant resistance device (Rc) 52, FET 53, pwm control circuit 54, capacitor 55, sampling and keeps FET 56, resistor 57, keeps timing circuit 58 and as the microcomputer 59 of control module.
DC-DC converter 51 is provided with the DC voltage VIN that is produced by power supply shown in Figure 4 31, and direct current by conversion and stable input, produce VD Vcc.DC-DC converter 51 and produce stable output voltage V cc, make that from the voltage Vf and the electric potential difference between the output voltage V cc of feedback terminal input be constant value (Vref).
The positive terminal of the light emitting diode 3 that is connected in series mutually is connected to the lead-out terminal of the output output voltage V cc of DC-DC converter 51 by constant resistance device (Rc) 52.The positive terminal of the light emitting diode 3 that is connected in series mutually also is connected to the feedback terminal of DC-DC converter 51 by the source electrode of sampling and maintenance FET 56 with draining.The negative pole end of the light emitting diode 3 that is connected in series mutually is by source electrode and the grounded drain of FET 53.
The grid of FET 53 is provided with the pwm signal that is produced by pwm control circuit 54.When pwm signal was ON, FET 53 connected drain electrode and source electrode, and when pwm signal was OFF, FET 53 disconnected drain electrode and source electrode.Therefore, when pwm signal was ON, FET 53 made electric current flow through light emitting diode 3, and when pwm signal was OFF, the electric current that will flow through light emitting diode 3 was reduced to zero.That is, when pwm signal was ON, FET 53 made light emitting diode 3 luminous, and when pwm signal was OFF, it is luminous that light emitting diode 3 is stopped.
Keep timing circuit 58 to be provided with pwm signal, and produce holding signal at the rising edge of pwm signal, this holding signal is OFF in the given time, and is being ON At All Other Times.
The grid of sampling and maintenance FET 56 is provided with the holding signal that keeps timing circuit 58 outputs.When holding signal was OFF, sampling and maintenance FET 56 connected source electrode and drain electrodes, when holding signal is ON, disconnected between source electrode and the drain electrode.
That is, in backlight drive control module 38, only during the pwm signal that is produced by pwm control circuit 54 was to connect, electric current I LED flow through light emitting diode 3.Capacitor 55, sampling and maintenance FET 56 and resistor 57 form sampling and holding circuits.This sampling and holding circuit are in pwm signal is the time of ON, to the positive pole of light emitting diode 3 (promptly, constant resistance device (Rc) 52 is not connected to the end of output voltage V cc) magnitude of voltage sample, and this magnitude of voltage is offered the feedback terminal of DC-DC converter 51.DC-DC converter 51 is based on the magnitude of voltage of the feedback terminal that is input to DC-DC converter 51, and regulated output voltage Vcc makes that the peak value of the electric current I LED that flows through constant resistance (Rc) 52 and light emitting diode 3 is constant.Therefore, in backlight drive control module 38, under the constant state of the peak value of the electric current I LED that flows through light emitting diode 3, carry out pulsed drive according to pwm signal.
When connecting color liquid crystal display arrangement 30, the dutycycle of microcomputer 59 when nonvolatile memory 60 reads every kind of color initial setting up, and this dutycycle offered pwm control circuit 54.For example, initial setting up is to carry out like this, the light emitting diode 3 that is every kind of color is provided with the peak value of dutycycle and electric current I LED roughly, make this dutycycle and peak value variable, and adjusting dutycycle and peak value, so that obtain the luminous flux of expectation and the colourity of expectation, and the luminous flux of the dutycycle of the light emitting diode 3 of every kind of color of storage, every kind of color and colourity and the output of temperature sensor 41 at this moment in nonvolatile memory 60 in advance before dispatching from the factory.
In addition, in order to obtain predetermined white light, microcomputer 59 is fixed the dutycycle of the light emitting diode 3 of any one color, and carries out the FEEDBACK CONTROL of the light emitting diode 3 of other two kinds of colors.Microcomputer 59 provides the target duty ratio to pwm control circuit 54, up to the ratio of luminous flux that detects every kind of color by luminous flux or chromaticity transducer 42 or the colourity ratio during with initial setting up consistent (, up to assembling) by the colourity of mixing the white light that R, G and B light obtains.
As mentioned above, in having the backlight drive control module 38 of microcomputer 59, at first produce the pwm signal of the dutycycle when having initial setting up, regulate dutycycle by FEEDBACK CONTROL then, so that, obtain predetermined white light with reference in the luminous flux or colourity by luminous flux or chromaticity transducer 42 detected every kind of colors.
Light emitting diode is the device that brightness weakens in time.In addition, the speed that weakens not only changes between the light emitting diode of different colours, and between the light emitting diode of same color, also change, this depends on the difference when making, the environment temperature of the environment that the temperature of light emitting diode, back lighting device 20 are placed etc.
Therefore, when brightness weakens greatly, thereby the dutycycle during from initial setting up that nonvolatile memory 60 reads and regulate after dutycycle between difference when increasing, the dutycycle of dutycycle when nonvolatile memory 60 is read initial setting up and the light emitting diode by regulating two kinds of other colors obtains the required time (convergence time) of predetermined white light and prolongs.Consequently, for example, screen is little red phenomenon that bleaches gradually afterwards when energized having occurred.In addition, when making the dutycycle increase of light emitting diode 3 owing to brightness deterioration, overall backlight power is compared increase with initial set value phenomenon appears.
Not only under the situation that above-mentioned brightness weakens in time, can cause the problems referred to above, and the dutycycle the when changing features of the LED that causes owing to reason such as annealing deficiency etc. and initial setting up and regulate after dutycycle between difference also can cause this problem when becoming very big.
Therefore, microcomputer 59 is the dutycycle when nonvolatile memory 60 is read as predetermined multiplication constant that every kind of color is provided with and initial setting up in fact, dutycycle by with initial setting up the time multiplies each other with the multiplication constant of reading, dutycycle when proofreading and correct initial setting up, and the dutycycle after the employing correction, thereby shortened the required time of colourity of assembling.
Specifically describe an example of the process of proofreading and correct dutycycle with reference to the process flow diagram of figure 7.Incidentally, regulate dutycycle,, fix the dutycycle of the light emitting diode 3 of any one color, and regulate the dutycycle of the light emitting diode 3 of two kinds of other colors so that obtain predetermined white light.Because temperature variant the variations minimum of the brightness of blue LED 3B and peak wavelength, therefore, in this instantiation, the fixing dutycycle of blue LED 3B.
At first, when connecting color liquid crystal display arrangement 30, microcomputer 59 versicolor dutycycle PWM when nonvolatile memory 60 reads initial setting up
R0, PWM
G0And PWM
B0And predetermined multiplication constant Kr, the Kg and the Kb that are provided with for shades of colour, multiply by dutycycle PWM with multiplication constant Kr, Kg and Kb respectively
R0, PWM
G0And PWM
B0, and result of product offered pwm control circuit 54 (step S1).The initial value of multiplication constant Kr, Kg and Kb is 1, therefore, and the dutycycle PWM during initial setting up
R0, PWM
G0And PWM
B0In statu quo offer pwm control circuit 54 at first.The pulsewidth that pwm control circuit 54 is regulated pwm signal is so that the dutycycle consistent with the dutycycle that is provided is provided.
Next, in order to obtain predetermined white light, microcomputer 59 is the dutycycle PWM of blue LED 3B fixedly
B0, and execution is red and the FEEDBACK CONTROL of green LED 3R and 3G.Microcomputer 59 changes the dutycycle of red and green LED 3R and 3G, and this dutycycle offered pwm control circuit 54, up to the ratio consistent (step S2) during with initial setting up by the ratio of the luminous flux of luminous flux or chromaticity transducer 42 detected every kind of colors or colourity.Suppose that as a result of when obtaining to be scheduled to white light, versicolor dutycycle is PWM
Rx, PWM
GxAnd PWM
B0
Handle though carried out this adjusting, the result of the long-time repetition Continuous irradiation of light emitting diode 3 is brightness deteriorations of light emitting diode 3.Microcomputer 59 changes dutycycle, so that proofread and correct such brightness deterioration.Suppose that as a result of versicolor dutycycle is PWM after regulating
Ry, PWM
GyAnd PWM
B0
A kind of update method is that multiplication constant Kb is fixed as 1, and the dutycycle PWM during according to initial setting up
R0And PWM
G0With the dutycycle PWM after the adjusting
RyAnd PWM
GyBetween ratio, upgrade multiplication constant Kr and Kg.
Yet, in this case,, might increase the dutycycle of light emitting diode 3 and increase power consumption backlight because compare with initial setting up, so can upgrade all multiplication constant Kr, Kg and Kb, make the increase of power consumption drop on such as within 5% the scope.Incidentally, make that Vr, Vg and Vb are the total voltages of lighting light emitting diode 3R, 3G and 3B respectively, make that Ir, Ig and Ib are the current values of lighting light emitting diode 3R, 3G and 3B respectively, can be by following equation rough calculation power consumption backlight:
Power＝Vr*PWM
R*Ir+Vg*PWM
g*Ig+Vb*PWM
b*Ib
In addition, the dutycycle PWM according to initial setting up the time
R0, PWM
G0And PWM
B0With versicolor dutycycle PWM after the adjusting
RxPWM
GxAnd PWM
B0Between ratio, determine can proofread and correct multiplication constant Kr, Kg and Kb after multiplication constant Kr, Kg and the Kb, make that its maximal value is 1, obtain new multiplication constant Kr, Kg and Kb.
Backlight drive control module 38 upgrades the value of multiplication constant Kr, Kg and Kb like this.Thereby when connecting color liquid crystal display arrangement 30 next time, the dutycycle that is similar to the final dutycycle after regulating is from beginning to be provided for pwm control circuit 54.Therefore, might shorten the required time of colourity of assembling.
It should be noted that to the invention is not restricted to the foregoing description, can under the situation that does not depart from spirit of the present invention, make various changes it.
For example, though in the foregoing description, versicolor initial setting up value and multiplication constant are stored in the nonvolatile memory 60, but the invention is not restricted to this, and the versicolor value of setting after regulating can be stored in the nonvolatile memory 60 with value at that time.In addition, for example, the information of the ratio of the value of setting of the value of setting of particular color and other color and the value of setting of particular color can be stored in the nonvolatile memory 60.That is, as long as can bear the data that are used for shortening every kind of color assembling the colourity required time when energized again, then these data can be stored in the nonvolatile memory 60 with arbitrary form.
The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (7)
1. a backlight drive device is used to control the driving of the back lighting device that is used for display, and described back lighting device generates predetermined white light by mixing from the light of a plurality of light emitting diodes of three kinds or more colors, and described backlight drive device comprises:
Memory storage is used to store the initial current amount and the predetermined multiplication constant of every kind of color;
The luminous flux detection device is used to detect the luminous flux of every kind of color; And
Control device, be used for described initial current amount and described predetermined multiplication constant are multiplied each other the magnitude of current that obtains as initial value, based on described luminous flux detection Device Testing output, pass through FEEDBACK CONTROL, the magnitude of current of the described light emitting diode of every kind of color is flow through in adjusting, generate described predetermined white light thus
Wherein, when the absolute value of the magnitude of current after the described FEEDBACK CONTROL and the difference between the described initial current amount surpassed predetermined threshold, described control device upgraded described multiplication constant according to the magnitude of current after the described FEEDBACK CONTROL.
2. backlight drive device according to claim 1,
Wherein, described control device fixed flow is crossed the magnitude of current of the light emitting diode of a kind of color in the described color, and regulates the magnitude of current of the light emitting diode that flows through described other color by described FEEDBACK CONTROL.
3. backlight drive device according to claim 1,
Wherein, the multiplication constant that described control device will be used for a kind of color of described color is set at 1, and upgrades the multiplication constant that is used for described other color.
4. backlight drive device according to claim 1,
Wherein, described control device upgrades described multiplication constant, makes that backlight power consumption is a scheduled volume or littler.
5. backlight drive device according to claim 1,
Wherein, described control device upgrades described multiplication constant, and the feasible maximal value that is used for the multiplication constant of a plurality of colors is 1.
6. a backlight driving method is used to control the driving of the back lighting device that is used for display,
Described back lighting device generates predetermined white light by mixing from the light of a plurality of light emitting diodes of three kinds or more colors, and described backlight driving method comprises:
Read step is used for being read as initial current amount and the predetermined multiplication constant that every kind of color is stored from memory storage;
The luminous flux detection step is used to detect the luminous flux of every kind of color;
Controlled step, be used for described initial current amount and described predetermined multiplication constant are multiplied each other the magnitude of current that obtains as initial value, export based on the detection in described luminous flux detection step, pass through FEEDBACK CONTROL, the magnitude of current of the described light emitting diode of every kind of color is flow through in adjusting, generates described predetermined white light thus; And
Step of updating is used for upgrading described multiplication constant according to the magnitude of current after the described FEEDBACK CONTROL when the absolute value of the magnitude of current after the described FEEDBACK CONTROL and the difference between the described initial current amount surpasses predetermined threshold.
7. liquid crystal indicator comprises:
Back lighting device is used for generating predetermined white light by mixing from the light of a plurality of light emitting diodes of three kinds or more colors, and described back lighting device is driven by backlight drive device; And
The transmission type colour liquid crystal display board, the described white light that is generated by described back lighting device from described transmission type colour liquid crystal displaying plate face,
Wherein, described backlight drive device comprises: memory storage is used to store the initial current amount and the predetermined multiplication constant of every kind of color; The luminous flux detection device is used to detect the luminous flux of every kind of color; And control device, be used for described initial current amount and described predetermined multiplication constant are multiplied each other the magnitude of current that obtains as initial value, based on described luminous flux detection Device Testing output, pass through FEEDBACK CONTROL, the magnitude of current of the described light emitting diode of every kind of color is flow through in adjusting, generate described predetermined white light thus, and when the absolute value of the magnitude of current after the described FEEDBACK CONTROL and the difference between the described initial current amount surpassed predetermined threshold, described control device upgraded described multiplication constant according to the magnitude of current after the described FEEDBACK CONTROL.
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| JP2004336571 | 2004-11-19 | ||
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| CN102132200B (en) * | 2009-09-02 | 2014-02-19 | 光远科技股份有限公司 | Rapid detection method of led backlight plate liquid crystal display attenuation and the display |
| JP5414468B2 (en) | 2009-11-09 | 2014-02-12 | 三洋電機株式会社 | LIGHT EMITTING ELEMENT DRIVE CIRCUIT SYSTEM AND ELECTRONIC DEVICE |
| CN102858072B (en) * | 2012-09-28 | 2014-12-17 | 北京半导体照明科技促进中心 | Lighting control method and system |
| CN116631306B (en) * | 2022-07-21 | 2024-02-23 | 宜宾市极米光电有限公司 | Brightness adjustment method, brightness adjustment device, display device and storage medium |
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Also Published As
| Publication number | Publication date |
|---|---|
| JP4992954B2 (en) | 2012-08-08 |
| JP2010033096A (en) | 2010-02-12 |
| CN1776488A (en) | 2006-05-24 |
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