Embodiment
See also Fig. 1, Fig. 1 is the present invention's one light-emitting diode (Light-Emitting Diode, LED) the function block schematic diagram of control system 10, led control system 10 be used for proofreading and correct a red light LED12a, a green light LED12b and a blue-light led 12c red light, green light and the blue light of output respectively.Red light, green light and blue light can synthesize white light with the light source as a backlight module.
LED control system 10 comprises an optical sensing subassembly 14, a reference value generation device 16, an input interface 18, an amplifier 20, a colourity comparison device 22, a brightness comparison device 24, one drive circuit 26 and a control device 28.Wherein optical sensing subassembly 14 includes a red light sensing cell 14a, a green light sensing cell 14b, a blue light sensing cell 14c, is used for the brightness or the intensity of light signal of red light, green light and blue light that sensing red light LED12a, green light LED12b respectively and blue-light led 12c exported; Optical sensing subassembly 14 also comprises a white light sensing cell 14d, is used for the brightness or the intensity of light signal of sensing red light, green light and the white light that blue light synthesized.Optical sensing subassembly 14 can be the TCS230 color sensor collocation three primary colors filter that TAOS company produced, so can sense the brightness or the intensity of light signal of the light (red light, green light, the white light that blue light synthesized) of red light, green light, blue light and non-filtered simultaneously.In addition, red light sensing cell 14a, a green light sensing cell 14b, a blue light sensing cell 14c and white light sensing cell 14d can be arranged on the same circuit board, and contiguous red light LED12a, green light LED12b and blue-light led 12c setting, make the circuit of light sensing unit to be provided with the circuit of LED.
Reference value generation device 16 is used for producing the reference value of red light, green light and blue light and a brightness reference value of the white light that red light, green light and blue light are synthesized.
Input interface 18 is coupled in reference value generation device 16, be used to provide the user and import brightness value, chromaticity coordinates value and color temperature value, for instance, the user can be by color parameters such as input interface 18 input CIE1931 chromaticity coordinates values or colour temperatures, and the reference value generation device 16 ratio yield value (meaning is the ratio of any two primitive color lights in the primaries) that can produce the ratio of red light brightness and green light brightness and blue light brightness and green light brightness according to color parameters such as this chromaticity coordinates value that input interface 18 transmitted or colour temperatures is with as the reference value afterwards; Or the user can directly import the brightness value of red light, green light and blue light by input interface 18, and reference value generation device 16 ratio (meaning is the ratio of any two primitive color lights in the primaries) that can produce the ratio of red light brightness and green light brightness and blue light brightness and green light brightness according to the brightness value that input interface 18 is transmitted is with as the reference value afterwards; In addition, the user can be by a brightness value of input interface 18 input white lights, and reference value generation device 16 can produce the brightness reference value of white light according to this brightness value that input interface 18 is transmitted afterwards.
Amplifier 20 is coupled in optical sensing subassembly 14, be used for amplifying the light signal of red light sensing cell 14a, green light sensing cell 14b, red light LED12a, green light LED12b that blue light sensing cell 14c is sensed respectively, red light that blue-light led 12c is exported, green light, blue light, and the light signal that amplifies white light sensing cell white light that 14d senses.
Colourity comparison device 22 is coupled in reference value generation device 16 and amplifier 20, is used for comparing the reference value of red light that reference value generation device 16 produced, green light, blue light and amplification that amplifier 20 the is transmitted light signal of red light, green light, blue light later.
Brightness comparison device 24 is coupled in reference value generation device 16 and amplifier 20, is used for comparing this brightness reference value of the white light that reference value generation device 16 produced and amplification that amplifier 20 the is transmitted light signal of white light later.
Drive circuit 26 is coupled in red light LED12a, green light LED12b, blue-light led 12c, is used for driving red light LED12a, green light LED12b, blue-light led 12c output red light, green light, blue light.
Control device 28 is coupled in colourity comparison device 22, brightness comparison device 24 and drive circuit 26, is used for according to the comparison result control Driver Circuit 26 driving red light LED12a of colourity comparison device 22 and brightness comparison device 24, the curtage of green light LED12b, blue-light led 12c.
See also Fig. 2, the flow chart of the red light that Fig. 2 is exported for led control system 10 correction red light LED12a of the present invention, green light LED12b, blue-light led 12c, green light, blue light, method of the present invention comprises the following step:
Step 100: a plurality of monochromatic reference values are provided.
Step 102: the brightness reference value that the light that a plurality of monochromatic light synthesizes is provided.
Step 104: these a plurality of monochromatic smooth signals that a plurality of light-emitting diode of sensing is exported.
Step 106: these a plurality of monochromatic light of sensing the light signal of synthetic light.
Step 108: these a plurality of monochromatic smooth signals that this a plurality of monochromatic reference value and step 104 sensed that comparison step 100 provides.
Step 110: the light signal of the light that this a plurality of monochromatic light synthesized that this brightness reference value and step 106 sensed of the light that this a plurality of monochromatic light synthesized that comparison step 102 provides.
Step 112: adjust these a plurality of monochromatic light that this a plurality of light-emitting diode is exported according to the step 108 and the comparison result of step 110.
In this above-mentioned steps is done an explanation, provide a plurality of monochromatic reference values and step 102 that a brightness reference value aspect of the light that a plurality of monochromatic light synthesizes is provided in step 100, at first the user can be by input interface 18 input brightness values, chromaticity coordinates value, or color temperature value, use and utilize reference value generation device 16 to produce corresponding red light, green light, blue light and white light reference value.For instance, the user can be by color parameters such as input interface 18 input CIE1931 chromaticity coordinates XY values or colour temperatures, with the reference value as a standard colorimetric (not colour cast), and reference value generation device 16 can calculate the standard ratio of primaries according to this chromaticity coordinates value that input interface 18 is transmitted.For example when input value during for chromaticity coordinates XY value, can be according to the color science formula:
In the hope of red light brightness, green light brightness and blue light brightness; If during the input color temperature value, can in the hope of pairing chromatic value, utilize aforesaid color science formula promptly also can try to achieve red light brightness, green light brightness and blue light brightness again according to Planck blackbody radiance curve (Planckian locus).Because human eye is the most responsive for green light, so can green light be that benchmark calculates the ratio of red light brightness and green light brightness and the ratio of blue light brightness and green light brightness, also maybe can adopt another primitive color light is that benchmark calculates the ratio of other two primitive color light with respect to this primitive color light, this moment, the ratio that drawn was red light, green light, the luminance standard ratio of blue light under standard colorimetric (not colour cast) situation, and as the reference value of red light, green light, blue light; Perhaps the user can directly import the brightness value of red light, green light and blue light by input interface 18, this moment, the brightness ratio value of red light, green light and blue light was luminance standard ratio under standard colorimetric (not colour cast) situation, and the standard ratio that reference value generation device 16 also can produce primaries according to the brightness value that input interface 18 is transmitted is with as the reference value.Moreover the user can be by the normal brightness value of input interface 18 input white lights, and reference value generation device 16 can produce the brightness reference value of white light according to this normal brightness value that input interface 18 is transmitted afterwards.
In these a plurality of monochromatic smooth signals that a plurality of light-emitting diode of step 104 sensing is exported, red light sensing cell 14a, green light sensing cell 14b, blue light sensing cell 14c can distinguish the brightness or the intensity of red light, green light and blue light that sensing red light LED12a, green light LED12b and blue-light led 12c exported; And the brightness or the intensity of white light sensing cell 14d sensing red light, green light and the white light that blue light synthesized.Next amplifier 20 can amplify the light signal of red light, green light, blue light and red light that red light sensing cell 14a, green light sensing cell 14b, blue light sensing cell 14c, white light sensing cell 14d are sensed respectively, green light, white light that blue light synthesized.
These a plurality of monochromatic smooth signals that this a plurality of monochromatic reference value and step 104 sensed that provide in step 108 comparison step 100 and step 110 are compared the light signal aspect of the light that this a plurality of monochromatic light synthesized that this brightness reference value and step 106 sensed of the light that this a plurality of monochromatic light synthesized that step 102 provides, the red light that colourity comparison device 22 comparison reference value generation devices 16 are transmitted, green light, the amplification that the reference value of blue light and amplifier 20 are transmitted is red light later, green light, the light signal of blue light, for instance, the amplification that colourity comparison device 22 is transmitted according to amplifier 20 is red light later, green light, the light signal of blue light calculates red light LED12a, the ratio of the red light brightness that green light LED12b and blue-light led 12c are exported and the ratio of green light brightness and blue light brightness and green light brightness, the reference value of the ratio of the ratio of red light brightness of being transmitted with reference value generation device 16 and green light brightness and blue light brightness and green light brightness is compared again, and comparison result transferred to control device 28, control device 28 can be according to the PID PID control method doing loop circuit control, as following formula:
Wherein e (t) is the margin of error, K
pBe proportional gain factor, T
iBe integration time constant, T
dBe derivative time constant.And then the proportional gain value (G of adjustment red light brightness and green light brightness
R/G) and the proportional gain value (G of blue light brightness and green light brightness
B/G), the red light brightness after feasible the adjustment is identical with the ratio and the reference value of the ratio of green light brightness and blue light brightness and green light brightness, and reaches the purpose of proofreading and correct colourity; In like manner, brightness comparison device 24 also can be compared this brightness reference value of the white light that reference value generation device 16 transmitted and amplification that amplifier 20 the is transmitted luminance signal of white light later, and comparison result transferred to control device 28, control device 28 is also controlled to do the loop circuit according to the PID PID control method as above-mentioned formula, and then adjusts the luminance gain value (G of red light, green light and blue light respectively
I), brightness value that make to adjust red light later, green light, white light that blue light synthesized is identical with brightness reference value, and reaches the purpose of correcting luminance.
Adjust these a plurality of monochromatic light that this a plurality of light-emitting diode is exported in step 112 according to the step 108 and the comparison result of step 110, control device 28 is imported corresponding driving signal to drive circuit 26 according to above-mentioned adjustment result, use the curtage that control Driver Circuit 26 drives red light LED12a, green light LED12b, blue-light led 12c, for instance, being the above voltage that drives red light LED12a, green light LED12b, blue-light led 12c can be corrected as follows respectively:
(proofreading and correct the voltage/current of rear drive red light LED12a)=(voltage/current of original driving red light LED12a) * (G
I) * (G
R/G);
(proofreading and correct the voltage/current of rear drive blue-light led 12c)=(voltage/current of original driving blue-light led 12c) * (G
I) * (G
B/G);
(proofreading and correct the voltage/current of rear drive green light LED12b)=(voltage/current of original driving green light LED12b) * (G
I)
Drive circuit 26 just can drive red light LED12a, green light LED12b, blue-light led 12c output red light, green light, blue light respectively according to the voltage/current of the voltage/current of proofreading and correct rear drive red light LED12a, the voltage/current of proofreading and correct rear drive green light LED12b, correction rear drive blue-light led 12c afterwards, proofreaies and correct red light LED12a, green light LED12b, blue-light led 12c institute output red light, green light, the brightness of blue light and the purpose of colourity and reach.And optical sensing subassembly 14 can continue red light, green light, blue light that sensing red light LED12a, green light LED12b, blue-light led 12c are sent, and form a loop circuit control system.
Below above-mentioned action principle done one illustrate more specifically, with use primaries at least each 80 hundred million light 99235 light-emitting diode be example, when colourity XY value is input as (0.33,0.33) time, conversion can obtain red light brightness, green light brightness, blue light brightness through the color science formula, after calculating, can obtain the ratio 0.386605 of red light brightness and green light brightness and the ratio 0.074277 of blue light brightness and green light brightness, the reference value that can obtain importing.Perhaps input color temperature reference value 5600K, can obtain colourity XY value according to Planck black-body radiation curve and be about (0.33,0.33), again through after the conversion of color science formula and calculating, also can try to achieve the ratio 0.386605 of red light brightness and green light brightness, and the ratio 0.074277 of blue light brightness and green light brightness, the also reference value that can obtain importing.And the white brightness input value is the reference value that 2000 lumens are used as brightness.Brightness value that reference value generation device 16 is transmitted according to input interface 18 and chromaticity coordinates value produce the reference value of this brightness reference value of white light and red light, green light, blue light.If opening the initial colourity XY value of red light LED12a, green light LED12b, blue-light led 12c is (0.268,0.313), the ratio 0.254495 of initial red light brightness and green light brightness, the ratio 0.099976 of blue light brightness and green light brightness, the initial current value is respectively 52mA, 157mA, 319mA, and this moment, brightness and temperature were respectively 3094.6 lumens and 44 ℃.The signal that detects red light, green light, blue light and white light that red light LED12a, green light LED12b and blue-light led 12c exported through 12bit red light sensing cell 14a, green light sensing cell 14b, blue light sensing cell 14c and white light sensing cell 14d is 532,1836,3732,1267 in regular turn, and it is 834,2520,5122,49686 in regular turn that the signal of input amplifier 20 is converted to the red light of 8bit, green light, blue light and white light signal.Export this signal amplification to colourity comparison device 22 and brightness comparison device 24 in regular turn via amplifier 20, the reference value that the light signal comparison reference value generation device 16 of the ratio of the ratio of red light brightness and green light brightness and blue light brightness and green light brightness was produced after colourity comparison device 22 amplified according to amplifier 20, with reference value to some extent during difference, approach reference value with pid control mode through calculating via control device 28, and the proportional gain value of output red brightness and green light brightness ratio and blue light brightness and green light brightness ratio is respectively 1.5197 with adjustment, 0.7432; The reference value that the light signal comparison reference value generation device 16 of white light was produced after brightness comparison device 24 amplified according to amplifier 20, with reference value to some extent during difference, approach reference value with pid control mode through calculating via control device 28 with adjustment, and the luminance gain value 0.646 of output red light, green light, blue light.See also Fig. 3, Fig. 3 is that gamma correction behind the led control system input reference 10 first time of the present invention, current correction and colour temperature change schematic diagram.The result that control device 28 is adjusted according to colourity comparison device 22 and brightness comparison device 24 proofreaies and correct drive circuit 26 and drives red light LED12a, green light LED12b, electric current 31.4mA, the 94.8mA of blue-light led 12c, 192.6mA.Via red light, green light, blue light colourity XY value after respectively drive current being exported to red light LED12a, green light LED12b, blue-light led 12c output after proofreading and correct and proofreading and correct is (0.3301,0.3301), the ratio of red light brightness and green light brightness be 0.38676 and the ratio of blue light brightness and green light brightness be 0.074307, the brightness and the temperature that are measured behind the elapsed time T1 are respectively 1999.1 lumens and 5600K, as shown in Figure 4, reach the purpose of adjusting correction.
In addition, from the above, behind input one group of reference brightness, color temperature value or chromatic value, import second group of reference value again or organize reference value more, also can realize proofreading and correct purpose.For instance, import second group of colour temperature 4300K or colourity XY value (0.37,0.37) time, through obtaining the ratio 0.457923 of corresponding red light brightness and green light brightness after the said method conversion, the ratio 0.049947 of blue light brightness and green light brightness, use the reference value of being used as colourity, the brightness input value is the reference value that 1500 lumens are used as brightness.Reference value generation device 16 produces reference value and sends it to colourity comparison device 22 and brightness comparison device 24 according to above-mentioned input value, this moment, the signal according to red light, green light, blue light and white light that 12bit red light sensing cell 14a, green light sensing cell 14b, blue light sensing cell 14c and white light sensing cell 14d are measured was 321,1109,2253,818 in regular turn, and it is 503,1522,3092,32078 in regular turn that the signal that inputs to amplifier 20 is converted to the red light of 8bit, green light, blue light and white light signal.Export this signal amplification to colourity comparison device 22 and brightness comparison device 24 in regular turn via amplifier 20, colourity comparison device 22 is according to reference value, approach reference value with pid control mode through calculating via control device 28, and the proportional gain value of output red brightness and green light brightness ratio and blue light brightness and green light brightness ratio is respectively 1.1845,0.6724 with adjustment; Brightness comparison device 24 amplifies the light signal comparison reference value of white light later according to amplifier 20, approaches reference value with pid control mode through calculating with adjustment via control device 28, and the luminance gain value 0.7504 of output red light, green light, blue light.See also Fig. 4, Fig. 4 is that gamma correction behind the led control system input reference 10 second time of the present invention, current correction and colour temperature change schematic diagram.The result that control device 28 is adjusted according to colourity comparison device 22 and brightness comparison device 24 proofreaies and correct drive circuit 26 and drives red light LED12a, green light LED12b, electric current 21.6mA, the 63.6mA of blue-light led 12c, 129.2mA.As shown in Figure 4, via respectively drive current is exported to red light LED12a, green light LED12b, blue-light led 12c output purpose red light, green light after proofreading and correct, blue light colourity XY value is (0.3701,0.3701), the ratio of red light brightness and green light brightness be 0.458106 and the ratio of blue light brightness and green light brightness be 0.049967, brightness that is measured behind the elapsed time T2 and temperature are 1500.1 lumens and 5600K, also can reach to adjust the purpose of proofreading and correct.
In addition, light source used in the present invention can be not limited to the primaries of red light, green light, blue light, also can use red light, green light, blue light and purple light four color light source, and its control principle is same as aforementioned principles, no longer describes in detail in this; Moreover in colourity control and brilliance control aspect, colourity control not necessarily needs to adjust simultaneously the luminance gain value (G of red light, green light and blue light
I), can adjust wherein a kind of brightness output of coloured light earlier, meet the chroma reference value of being imported in other two kinds of coloured light of colourity control with the ratio that before had been adjusted coloured light more afterwards and get final product.
In addition, see also Fig. 5, Fig. 5 has the function block schematic diagram of the led control system 10 of temperature sensing function for the present invention.Can influence the usefulness of light-emitting diode because the backlight module temperature inside raises, therefore, led control system 10 also can comprise a temperature sensing unit 30 and a temperature comparison device 32.Temperature sensing unit 30 is arranged in the backlight module temperature in order to the sensing backlight module, and to produce a sensing temperature value, specifically, temperature sensing unit 30 is used for a plurality of monochromatic temperature that a plurality of light-emitting diode of sensing is exported.Temperature comparison device 32 is coupled in temperature sensing unit 30, reference value generation device 16 and control device 28, be used for comparing the sensing temperature value that temperature reference value that reference value generation device 16 produced and temperature sensing unit 30 are transmitted, the user can be by input interface 18 input temp reference values.Control device 28 is used for according to the comparison result control Driver Circuit 26 driving red light LED12a of temperature comparison device 32, the curtage of green light LED12b, blue-light led 12c.
A plurality of monochromatic method and the led control system exported compared to a plurality of light-emitting diode of existing correction, the present invention use a plurality of monochromatic indivedual signals that sense as the control of the loop circuit of colourity, add the loop circuit control of the brightness of the light source that this a plurality of monochromatic light that senses synthesizes as brightness, and the temperature value that is sensed is as the loop circuit control of LED brightness, just can supply thus to have now only divides other sensing signal as the feedback signal with primaries, but the brightness value of backlight module institute output light source is to divide other shortcoming that brightness value COMPREHENSIVE CALCULATING is drawn with primaries, so can directly carry out feedback control, and improve the LED source problem of unstable veritably to the brightness of light source.
The above only is preferred embodiment of the present invention, and all equalizations of doing according to claim of the present invention change and modify, and all should belong to the covering scope of patent of the present invention.