WO2016124106A1

WO2016124106A1 - Led light source module having high color rendering index and led lamp

Info

Publication number: WO2016124106A1
Application number: PCT/CN2016/072571
Authority: WO
Inventors: 余建华; 谌江波; 鄂雷
Original assignee: 深圳大学
Priority date: 2015-02-04
Filing date: 2016-01-28
Publication date: 2016-08-11
Also published as: CN104633499A; CN104633499B

Abstract

An LED light source module and LED lamp, the LED light source module comprising a first LED light source (401) providing warm white light, a second LED light source providing blue light (402), a third LED light source (403) providing green light and a fourth LED light source (404) providing red light. The first LED light source (401) comprises a first blue light LED chip having a peak wavelength of 442-450 nm, the first blue light LED chip being coated with a green light fluorescent powder having a peak wavelength of 525-540 nm and an orange fluorescent powder having a peak wavelength of 580-600 nm, and the proportions of luminous powers of blue light, green light and orange light in the warm white light are 0.02-0.04, 0.35-0.39 and 0.59-0.61 respectively. The second LED light source (402) comprises a second blue light LED chip having a peak wavelength of 442-450 nm. The third LED light source (403) comprises a green light LED chip having a peak wavelength of 490-500 nm. The fourth LED light source (404) comprises a red light LED chip having a peak wavelength of 627-635 nm. The LED light source module and a light distribution scheme of the LED lamp are easy to achieve, and have a favorable light distribution effect.

Description

LED color light source module with high color rendering index and LED lamp

[Technical Field]

The invention relates to LED lighting technology, in particular to an LED light source module and an LED lamp with high color rendering index.

【Background technique】

As a new generation of illumination source, the LED chip produces white light illumination scheme, which is widely used in lighting field due to its high efficiency, energy saving, green environmental protection and long life. With the improvement of living standards, people's requirements for lighting quality are getting higher and higher. Not only the color temperature can be adjusted, but also a high color rendering index, especially in some special applications, such as museums, hospitals, art rooms, etc., the color rendering index is higher, all above 90, some special The requirement of the color index R9 is also above 90 or higher.

There are three main methods for producing white light through an LED chip: (1) a blue LED chip + a YAG yellow phosphor. The GaN-based blue LED chip is used to excite the YAG phosphor to emit yellow light, which is mixed with the remaining blue light to produce white light. By adjusting the intensity ratio of blue light and yellow light, white light of different color temperatures can be produced. The scheme for realizing white light, the product and the production process are relatively simple, the technology is becoming mature, and the commercialization has been realized, and it is currently the mainstream technology for manufacturing white LED. However, the white light produced by this scheme can only be a fixed color temperature, and the general color rendering index Ra is usually only 60-80, the special color rendering index R9 is also very low, and the low R9 will make the color of the object dim. (2) Near-ultraviolet LED chip + RGB phosphor. The RGB phosphor is excited by the ultraviolet light emitted by the near-ultraviolet LED chip to synthesize white light. The color of the phosphor is changed by adjusting the ratio of the phosphor to obtain the desired white light, and a better color temperature and color rendering index can be obtained, but the applicable near-ultraviolet LED chip has not yet formed a mature application. (3) R, G, B three primary colors synthesize white light. The R, G, and B primary color LED chips are packaged in a single device. By adjusting the driving currents of the three color chips separately to change the ratio of the three color lights, various colors of light can be obtained, and a wide band can also be obtained. White light. However, under this method, it is difficult to determine the light distribution scheme of the LED chip, and in particular, it is difficult to determine a light distribution scheme with a good light distribution effect. The so-called good light distribution effect means that the color temperature can be adjusted within a wide range (2700 ~ 6500K), and can maintain a high color rendering index within the range (high color rendering index means that the general color rendering index Ra is More than 90).

In addition, when the LED chip is mixed with light to obtain white light, there is also the same defect as most illumination sources, that is, the problem of light decay. The most direct manifestation of light decay is the luminous flux that affects the LED. The light decay also has a color temperature and color rendering index. The impact of this will make it difficult to apply LEDs to applications where medical light, photography, etc. have high requirements for light sources. Therefore, how to effectively reduce the light decay is also a major problem facing LED.

[Summary of the Invention]

The technical problem to be solved by the invention is to make up for the deficiencies of the above prior art, and to provide an LED light source module and an LED lamp, which can realize the color temperature adjustable within the range of 2700K-6500K, and the color rendering index Ra in the color temperature range. R9 is above 95, and all color rendering indexes R1 to R15 are above 90, and the chromaticity difference ΔC is less than 0.0054.

The technical problem of the present invention is solved by the following technical solutions:

A high color rendering index LED light source module, the LED light source module comprising a first LED light source providing warm white light, a second LED light source providing blue light, a third LED light source providing cyan light and a red light providing a four LED light source; the first LED light source comprises a first blue LED chip having a peak wavelength of 442 to 450 nm, which is coated with a green light phosphor having a peak wavelength of 525-540 nm and an orange light phosphor of 580-600 nm. The ratio of the optical power occupied by the blue light in the warm white light is 0.02 to 0.04, the ratio of the optical power occupied by the green light is 0.35 to 0.39, and the ratio of the optical power occupied by the orange light is 0.59 to 0.61; the second LED The light source includes a second blue LED chip having a peak wavelength of 442 to 450 nm; the third LED light source includes a cyan LED chip having a peak wavelength of 490 to 500 nm; and the fourth LED light source includes red light having a peak wavelength of 627 to 635 nm. LED chip.

An LED lamp with high color rendering index, comprising a heat sink, a reflector, a diffusion plate and a substrate on which the LED light source module is disposed, the LED light source module comprising at least one set of LED light source modules, the LED light source module For the LED light source module as described above, the LED light fixture further includes four driving circuits and a control circuit; the control circuit stores a correspondence between the luminous flux ratio of each LED light source and the chromaticity parameter of the mixed white light. Relationship table, wherein under the luminous flux ratio of each light source, each chromaticity parameter satisfies the following conditions: the color temperature is adjustable within the range of 2700K to 6500K, and the general color rendering index Ra ≥ 95 of the light source at each color temperature, and the special color rendering index R9 ≥ 95 , all color rendering indexes R1 R R15 ≥ 90, chromaticity difference ΔC < 0.0054; the control circuit selects the corresponding luminous flux ratio of each LED light source according to the mixed color temperature obtained by the user, according to the luminous flux of each LED light source The ratio determines the driving current of each LED light source, and outputs the calculated driving current to the corresponding driving circuit respectively; the four driving circuits respectively output the received driving current to LED light source should drive the corresponding LED light emission.

The beneficial effects of the present invention compared to the prior art are:

The LED light source module and the LED lamp of the invention, the LED light source module is a special first blue LED chip, the second blue LED chip, the cyan LED chip and the red LED chip, through the wavelength of each LED chip And the matching of the corresponding phosphor wavelengths to produce a mixed light of a specific spectral power distribution. When used in LED luminaires in the future, in conjunction with the control circuit in the luminaire, the control circuit stores in advance the correspondence table between the luminous flux ratio and the chromaticity parameter of each light source satisfying the condition, and selects the luminous flux of each light source according to the color temperature obtained. Proportion, thereby determining the driving current output to each light source to drive the light to obtain the desired color temperature, and the color rendering index Ra and R9 of the obtained light source are both ≥95, and all the color rendering indexes R1 to R15 are ≥90, and the chromaticity is poor. △ C < 0.0054. In the LED lamp of the invention, under the premise that the color temperature is adjustable within the range of 2700K-6500K, the display indexes Ra and R9 are ≥95, and all the color rendering indexes R1 R15 are ≥90, and the chromaticity difference ΔC<0.0054, The chromaticity parameter is good, close to natural light, and can simulate the application of natural light to meet high requirements. At the same time, in the mixed light scheme, only one LED chip and the phosphor generate excitation light, and the other three LED chips directly emit light, and the phosphor is not required to generate excitation light, so that the scheme is easy to realize control, and the feedback adjustment is facilitated later.

[Description of the Drawings]

1 is a schematic structural view of an LED lamp in an embodiment of the present invention;

2 is a circuit diagram of an LED lamp in an embodiment of the present invention;

3 is a schematic structural view of an LED light source module in an LED lamp according to an embodiment of the present invention;

4 is a relative spectral power distribution diagram of each chip and phosphor selected in a combination of LED lamps in an embodiment of the present invention;

5 is a relative spectral power distribution diagram of light of four colors generated by an LED lamp in a combination and a set of optical power ratios in a specific embodiment of the present invention;

6 is a schematic diagram showing a color gamut range of light of four colors of a LED lamp in a combination and a set of blue light ratios according to an embodiment of the present invention;

7 is a flow chart of a method for calculating a luminous flux ratio satisfying a condition in a specific embodiment of the present invention;

8 is a relative spectral power distribution diagram of white light obtained by mixing LED lamps in a combination and a set of optical power ratios according to an embodiment of the present invention;

FIG. 9 is a schematic diagram showing the workflow of the LED lamp in the preferred embodiment of the present invention.

【Detailed ways】

The present invention will be further described in detail below in conjunction with the specific embodiments and with reference to the accompanying drawings.

Based on the LED and phosphor luminescence spectrum model, the LED light mixing scheme is deeply studied, and a set of LED light source combination schemes can be used to realize the color rendering characteristics of R1 to R15 which are not realized in the past. . Some previous LED light source combination schemes, such as the public day of January 1, 2014, are open. In the LED lamp of CN103486466A, no matter how to control and adjust the luminous flux ratio of each mixed light LED source, the high R1～R15 index cannot be obtained, so that it is impossible to realize Ra and R9≥95 under a certain luminous flux ratio. The color indexes R1 to R15 are also ≥90, and the chromaticity difference ΔC<0.0054. This is determined by the intrinsic properties of the spectral power distribution of the LED light source participating in the mixed light under its LED light mixing scheme. When the light mixing is the spectral power distribution in the above disclosed scheme, since the spectral power distribution has been determined, no matter what How to adjust the optical power ratio of each light participating in the mixed light, and it is impossible to realize that all the color rendering indexes R1 to R15 are also ≥90. In the LED light source combination scheme of the present invention, the LED light mixing light source and the optical power ratio of each light component are adjusted, thereby obtaining a new spectral power distribution of four kinds of light participating in the mixed light, and further combining the control adjustment, and finally Not only Ra and R9 ≥ 95 can be realized, but also all the color rendering indexes R1 to R15 are ≥ 90, and the chromaticity difference ΔC < 0.0054. Since all the color rendering indexes R1 to R15 are ≥90, the color rendering characteristics are close to natural light, which can meet the demanding application.

1 and 2 are schematic structural diagrams and circuit diagrams of the LED lamp in the specific embodiment. The LED lamp includes a heat sink 1, a reflector 2, a diffusion plate 3, and a substrate 5 on which the LED light source module 4 is disposed. The LED light source module 4 includes at least one set of LED light source modules (multiple sets are shown), and the LED light fixture further includes four

drive circuits

701, 702, 703, and 704 and a control circuit 6.

The LED light source module 4 includes a plurality of LED light source modules, each of which includes four LED light sources, respectively a first LED light source 401 for providing warm white light, and a second LED light source 402 for providing blue light, providing blue light. A third LED light source 403 and a fourth LED light source 404 that provides red light.

The first LED light source 401 includes a first blue LED chip having a peak wavelength of 442 to 450 nm, and is coated with a green light phosphor having a peak wavelength of 525 to 540 nm and an orange light phosphor of 580 to 600 nm, thereby being first. The blue LED chip excites the mixed phosphor of the green phosphor and the orange phosphor to produce warm white light. By adjusting the mixing ratio and coating amount of each phosphor in the mixed phosphor, the ratio of the optical power occupied by the blue light in the generated warm white light is 0.02 to 0.04, and the ratio of the optical power occupied by the green light is 0.35 to 0.39, orange light. The proportion of optical power is 0.59 to 0.61. In the specific embodiment, a blue LED chip with a peak wavelength of 445 nm is used to excite a mixed phosphor composed of a green light phosphor of 538 nm and an orange light phosphor of 585 nm to generate warm white light, and the ratio of optical power occupied by blue light in warm white light is 0.027. The proportion of optical power occupied by green light is 0.367, and the ratio of optical power occupied by orange light is 0.606.

The second LED light source 402 includes a second blue LED chip having a peak wavelength of 442 to 450 nm, providing blue light. In this embodiment, a blue LED chip having a peak wavelength of 445 nm is used.

The third LED light source 403 includes a cyan LED chip having a peak wavelength of 490 to 500 nm, and provides cyan light. Ben In a specific embodiment, a cyan LED chip having a peak wavelength of 495 nm is used.

The fourth LED light source 404 includes a red LED chip having a peak wavelength of 627 to 635 nm, which provides red light. In this embodiment, a red LED having a peak wavelength of 630 nm is used.

When the LED light sources are arranged to form the LED light source module, they can be arranged in any convenient manner, such as a square, a rectangle, or a circle. Preferably, in a circular preferred manner as shown in FIG. 3, a plurality of LED light sources in the LED light source module are arranged in a circular shape, and LED light sources providing different colors of light are spaced apart. FIG. 9 shows a case where five groups of LED light source modules constitute an LED light source module. In each group of LED light source modules, a circular white LED light source 401, a blue LED light source 402, and a cyan LED light source are arranged in a circular arc shape. 403. A red LED light source 404. The order of the arc arrangement is not limited in the figure, and may be arranged in other order, such as blue LED light source 402, blue-green LED light source 401, cyan LED light source 403, red LED light source 404, blue LED light source 402, as long as the whole The LED light sources of different colors of light on the circle may be arranged at intervals. According to the above circular arrangement, the light emitted by each light source can be better concentrated, thereby achieving a better light mixing effect.

As shown in FIG. 4, it is the first LED light source selected in the specific embodiment (a mixed phosphor composed of a 538 nm green phosphor and a 585 nm orange phosphor excited by a blue LED chip having a peak wavelength of 445 nm), and a second The relative spectral power distribution of each chip and phosphor in the LED light source (blue LED chip of 445 nm), the third LED light source (cyan LED chip of 495 nm), and the fourth LED light source (630 nm red LED chip). In Fig. 4, B_445 represents a blue LED chip, B_495 represents a cyan LED chip, G represents a green phosphor, R represents a red LED chip, and O represents an orange phosphor. Under the above combination, the proportion of the phosphor powder, the mixing ratio and the coating amount are adjusted so that the ratio of the optical power occupied by the blue light in the warm white light is 0.027, and the ratio of the optical power occupied by the green light is 0.367, and the light occupied by the orange light The power ratio is 0.606, so the relative spectral power distribution of warm white light, blue light, cyan light and red light generated by the four LED light sources respectively is as shown in FIG. 5.

In Fig. 5, B_G_O indicates warm white light, B_445 indicates blue light, B_495 indicates blue light, and R_630 indicates red light. In the above combination and ratio, the color coordinates of the warm white light, blue light, cyan light and red light generated are: (0.41, 0.49), (0.16, 0.02), (0.08, 0.36), (0.70, 0.30), respectively. A schematic diagram of the gamut range is shown in Figure 6. It can be seen from Fig. 6 that the quadrilateral range of the color coordinates of the four colors of light covers the energy gamut gamut range, indicating that the light obtained by mixing the four lights in the color coordinate can achieve a color temperature ranging from 2700K to 6500K. Adjustable inside.

It should be noted that when a combination of other values in the range is selected, the peak value of the waveform in FIG. 5 will move. When the ratio of the optical power occupied by the blue light, the green light, and the orange light in the warm white light is set to other values in the range, the relative power value at the corresponding wavelength may vary, and the compression opening condition of the waveform may be different. But regardless of the peak value of the waveform, or The waveform shrinkage changes, generally in the 442 ~ 450nm blue LED chip, 525 ~ 540nm green phosphor and 580 ~ 600nm orange phosphor mixed fluorescent powder, 490 ~ 500nm cyan LED chip, 627 ~ Under the combination of the 635 nm red LED chip, when the optical power ratio of the corresponding light in the warm white light is in the foregoing range, the relative spectral power distribution pattern of the mixed light is similar to that of FIG. 5, and the color coordinates of the obtained four colors of light are formed. The quadrilateral can also cover the energy gamut gamut range, and the light obtained by the four kinds of light mixing can also be adjusted in the range of 2700K to 6500K.

When the circuit component of the LED lamp works: the control circuit 6 stores a correspondence table between the luminous flux ratio of each light source and the chromaticity parameter of the mixed light source, wherein under the luminous flux ratio of each light source, each chromaticity parameter satisfies the following Conditions: The color temperature can be adjusted within the range of 2700K~6500K. The general color rendering index Ra≥95 of the light source at each color temperature, the special color rendering index R9≥95, all the color rendering indexes R1～R15 are ≥90, the chromaticity difference △C< 0.0054; the control circuit selects the corresponding luminous flux ratio of each light source according to the mixed color temperature obtained by the user, determines the driving current of each light source according to the luminous flux ratio of each light source, and outputs the calculated driving current to the corresponding driving circuit respectively. 701, 702, 703, and 704.

The four

drive circuits

701, 702, 703, and 704 respectively output the received drive currents to the respective LED

light sources

401, 402, 403, and 404, and drive the corresponding LED light sources to emit light. The four-

way driving circuits

701, 702, 703, and 704 respectively drive the four LED light sources by the adjustment mode of the pulse width adjustment PWM. The PWM adjustment mode adjusts the pulse width of the input current of each LED light source, so that the LED light source always works at full amplitude current and zero, reducing the shift of the chromatogram. The microcontroller can be used to generate a PWM signal using a 16-bit timer, which is divided into 65536 gray levels. This improves control accuracy and softens the lighting process.

The control circuit 6 adjusts the driving current through the driving circuit, thereby controlling the luminous flux output of each light source, and causing the LED lamp to output the mixed white light obtained by mixing the corresponding luminous flux ratios, thereby outputting the mixed white light at a desired color temperature, and dividing the color temperature. The general color rendering index Ra and the special color rendering index R9 are all above 95, and all of the color rendering indexes R1 to R15 are above 90.

As described in detail below, how to obtain a correspondence table between the luminous flux ratio and the chromaticity parameter of the source after mixing.

First, the chromaticity parameters such as the color temperature, color rendering index, and chromaticity difference of the light source are determined by the relative spectral power distribution and optical power ratio of the four color lights participating in the mixed light. The relative spectral power distribution S(λ) of the light after mixing is calculated as shown in equation (1):

S(λ)=K ₁ *S ₁ (λ)+K ₂ *S ₂ (λ)+K ₃ *S ₃ (λ)+K ₄ *S ₄ (λ) (1)

Wherein, S ₁ (λ), S ₂ (λ), S ₃ (λ), and S ₄ (λ) are relative spectral power distributions of warm white light, blue light, cyan light, and red light participating in light mixing, respectively, K ₁ , K ₂ , K ₃ , and K ₄ are optical power ratios corresponding to warm white light, blue light, cyan light, and red light that participate in light mixing. Therefore, in order to determine the color temperature and color rendering index of the light after mixing, it is necessary to know the relative spectral power distribution of the LEDs participating in the light mixing and the optical power ratio between them. As described above, when the peak wavelength of the LED chip and the phosphor used and the amount of the phosphor are determined, the spectral power distribution of the four kinds of light participating in the mixed light is determined (as shown in FIG. 5). Therefore, setting different optical power ratio combinations will result in different S(λ), and S(λ) will eventually affect the value of the chromaticity parameter (the color temperature is calculated by S(λ), the general color rendering index Ra, special Formulas for chromaticity parameters such as color rendering index R9, chromatic aberration, and radiation efficiency are known). In summary, different optical power ratios have different color temperatures, color rendering indexes, and chromaticity differences.

As shown in FIG. 7, a flow chart of a method for calculating a luminous flux ratio that satisfies the condition. As shown in FIG. 7, the following steps are included: 1) receiving relative spectral power distribution data of warm white light, blue light, cyan light, and red light. 2) Assigning a warm white light power ratio K1, a blue light power ratio K2, a cyan light power ratio K3, and a red light power ratio K4. 3) Calculate the chromaticity parameters of the mixed light. Specifically, the relative spectral power distribution of the mixed light is calculated according to the above formula (1), and then the chromaticity parameters of the mixed light source are calculated according to the relative spectral power distribution of the mixed light, and the chromaticity parameters include the color temperature, and the general color rendering index Ra. , all color rendering index R1 ~ R15, chromaticity difference and radiation efficiency. There are known calculation formulas for calculating the above chromaticity parameters based on the relative spectral power distribution S(λ) of the mixed light, which will not be described in detail herein. 4) Determine whether the following conditions are met: the color temperature of the mixed light is within the set range (ie, it can fluctuate within a certain range of the set value. For example, if the color temperature is set to 2700K, the color temperature can be in the range of 2695 to 2705K. Considered as color temperature 2700K), general color rendering index Ra≥95, special color rendering index R9≥95, all color rendering indexes R1～R15 are ≥90, chromaticity difference △C<0.0054, if yes, proceed to step 5) Output warm white light power ratio K1, blue power ratio K2, cyan light power ratio K3 and red light power ratio K4 current value, and the corresponding current chromaticity parameter value; if not, then return Step 2) Re-assign and recalculate until the warm white light power ratio K1, the blue power ratio K2, the cyan light power ratio K3, and the red light power ratio K4 satisfying the condition are obtained.

After obtaining the optical power ratios K1, K2, K3, and K4 satisfying the conditions, since there is a corresponding relationship between the optical power ratio and the luminous flux ratio, the luminous flux ratio can be calculated according to the optical power ratio. The calculation formula is:

Where η _n , K _n , and LER _n correspond to the respective light sources (n=1 corresponds to warm white light, n=2 corresponds to blue light, n=3 corresponds to cyan, and n=4 corresponds to red light) Luminous flux ratio, optical power ratio and radiation efficiency, the value of a _m is 683 lm / W, V (λ) is the visual function, and S (λ) is the relative power spectral distribution data of the corresponding light source.

According to the above calculation method, the luminous flux ratio of each light source and the color temperature of the mixed light source, the general color rendering index Ra, the special color rendering index R9, all the color rendering indexes R1 to R15, and the correspondence between the chromaticity differences ΔC can be obtained. Relationship, and the color temperature is adjustable in the range of 2700K~6500K. The general color rendering index Ra≥95 of the light source after mixing at different color temperatures, the special color rendering index R9≥95, all color rendering indexes R1～R15 are ≥90, chromatic products The difference ΔC<0.0054.

Still using the selected first LED light source (a hybrid phosphor composed of a 538 nm green phosphor and a 585 nm orange phosphor excited by a blue LED chip having a peak wavelength of 445 nm), and a second LED light source (a 445 nm blue LED chip), Three LED light source (495nm cyan LED chip), fourth LED light source (630nm red LED chip), and the proportion of optical power occupied by blue light in the warm white light emitted by the first LED light source is 0.027, the light occupied by green light The power ratio is 0.367, and the ratio of the optical power occupied by the orange light is 0.606. For example, the correspondence between the obtained luminous flux ratio of the white light and the respective chromaticity parameters is as shown in Table 1 and Table 2. The relative power spectral distribution of the rear white light is shown in Fig. 8.

Table 1 Ra, △C and LER parameters of white light after mixing

Table 2 R1 ~ R15 parameters of white light after mixing

It can be seen from the data in Table 1 and Table 2 that by controlling the luminous flux ratio of four kinds of LEDs, such as warm white light, blue light, cyan light and red light, the mixed light of the corresponding color temperature can be obtained, and the color temperature can be realized from 2700K to The range of 6500K is adjustable. At the same time, except for the color rendering index Ra and R9 are above 95, all the color rendering indexes R1 to R15 are also above 90, which is close to natural light. The chromaticity difference ΔC is less than 0.0054, and the chromaticity performance is very good. The radiation efficacy (LER) is above 290 lm/W and the highest radiation efficacy (LER) is 347 lm/W.

It can be seen from the relative spectral power distribution diagram of the mixed white light in FIG. 8 that the LED lamp can be adjusted in the color temperature range of 2700K to 6500K.

In the specific embodiment, the LED lamp adopts four kinds of LED light sources, which are respectively a blue phosphor chip to excite a mixed phosphor composed of a green phosphor and an orange phosphor to generate warm white light, and a blue LED chip generates blue light and a cyan LED chip. Cyan, and red LED chips produce red light. By combining a certain range of peak wavelength combinations and the ratio of optical powers of the respective light components, four kinds of light of a specific spectral power distribution are obtained and mixed. When mixing light, only three kinds of LED chips and two kinds of phosphors are involved, and the light mixing scheme is simple and easy. During operation, the currents of different LED light sources are adjusted by the control circuit and the driving circuit, thereby adjusting the luminous flux output of different LED light sources, adjusting the ratio of the luminous flux between them, and obtaining the mixed white light at the corresponding color temperature under the respective luminous flux ratios, And the chromaticity parameters of white light are better. Except for Ra and R9 above 95, R1~R15 are also above 90, close to natural light, good color rendering index, good chromaticity and radiation efficiency, and also good Satisfied color The temperature is adjustable, and the LED lamp of the specific embodiment can meet the demanding application.

Preferably, the reflector 2 in the LED lamp is a frosted reflector, the substrate 5 is plated with a reflective film, and the diffuser 3 is one of a PC diffusion plate, a PMMA diffusion plate or a frosted glass, thereby improving the LED through the arrangement on the lamp assembly. The spot effect of the luminaire, the light utilization rate and the uniformity of the emitted light.

Further preferably, the acquisition and feedback control are set to improve the color temperature instability caused by light decay after the LED lamp has been used for a period of time. Due to the long-term use, the LED lamp bead will undergo light decay, resulting in a change in the color temperature of the mixed white light emitted by the LED light source module. The color temperature of the emitted white light is related to the light stimulation values of the three colors R, G, and B in the white light, and the light stimulation values of the three colors can be approximated as the fourth LED light source among the four light sources (the red LED light source). ), a third LED light source (cyan LED light source), and a second LED light source (blue LED light source). When light decay occurs, by adjusting the luminous flux of three kinds of LED light sources of red, cyan and blue light, that is, adjusting the driving currents of three kinds of LED light sources of red, cyan and blue light, thereby illuminating the RGB three-channel light of white light after mixing. The value changes, so that the color temperature value of the light source can be changed to resist the color temperature fluctuation caused by the light decay.

Specifically, the LED luminaire further includes a color sensor (for example, a TCS3414 color sensor), and the color sensor is disposed in the luminaire, such as a reflector, for collecting red light stimulation value in the mixed white light emitted by the LED light source module, and the green light Stimulus value and blue light stimulation value. After the acquisition, the acquired values are output to the control circuit 6.

The control circuit 6 stores standard stimuli values of red, green, and blue light corresponding to the white light at various color temperatures after mixing. As shown in Table 1, at each color temperature, there is a luminous flux ratio under four LED light sources. According to formula (1), the relative spectral power distribution S(λ) of white light after mixing can be obtained, combined with red light and green in white light. The spectral stimulus values of light and blue light can be used to calculate the tristimulus values of white light in red, green and blue light in the CIE 1931-RGB system. At each color temperature, a set of tristimulus values is calculated, which is taken as the standard stimulus value. The control circuit 6 stores the correspondence relationship between the color temperature and the stimulus values of the three colors of red, green, and blue for the subsequent adjustment process. The following feedback adjustment is performed in the control circuit 6:

1) Calculating a current actual color temperature value of the white light based on the acquired stimulation value.

2) Compare the current actual color temperature value with the standard color temperature value to determine whether the difference between the two is less than or equal to ΔT, and if so, keep the previous driving current unchanged; if not, proceed to step 3). The standard color temperature value is a color temperature value of the mixed white light that the user needs to obtain. For example, if it is desired to be 3000K, the standard color temperature value in this step is 3000K. ΔT is the difference threshold set by the user. For example, if there is only a difference of 50K, ΔT=50K. This The two values can be set according to the user's needs.

3) adjusting the fourth LED light source, the third LED light source and the second LED light source according to the comparison results of the collected red, green and blue light stimulus values and the standard stimulus values of red light, green light and blue light respectively The luminous flux ratio is adjusted to adjust the corresponding driving current; after the adjustment, return to step 1), and the adjustment process is repeated until the difference between the current actual color temperature value and the standard color temperature value is less than ΔT.

After setting the color sensor and the control circuit according to the above manner, as shown in FIG. 9, the working process of the LED lamp is as follows:

During initialization, the user sets the desired color temperature and adjusts the color temperature file of the fixture to this level. At initialization, an initial PWM control signal is generated in control circuit 6 to initialize the luminaire. Of course, during the initialization process, the user also sets the allowed color temperature difference threshold ΔT.

In the feedback adjustment, the color temperature selected by the user initialization is used as the standard color temperature value, and the standard color temperature value and the stimulation values of the three colors R, G, and B at the standard color temperature are stored in the control circuit 6 (for example, MCU). The control circuit 6 outputs driving currents corresponding to the four LED light sources to the driving

circuits

701, 702, 703 and 704, respectively adjusting the current duty ratios of the four white light sources of warm white light, blue, cyan and red light, thereby realizing the designation in the luminaire White color of color temperature. Here, when the above-described feedback adjustment is performed, the first LED light source (warm white light) is not adjusted, that is, the drive current of the original output to the drive circuit 701 is always maintained. R, G, and B are respectively adjusted corresponding to red light, cyan light, and blue light, and the drive currents of the

drive circuits

704, 703, and 702 are adjusted correspondingly.

The color sensor collects the R, G, and B stimuli values of the emitted white light, and feeds back the collected three stimuli values back to the MCU, and calculates the color temperature value of the light source by conversion. For example, according to the Commission International de L'Eclairage The (CIE) standard is converted to the x, y color coordinates on the chromaticity diagram, and then the current actual color temperature value of the light source is derived from the x, y color coordinates according to the formula. Compare this actual color temperature with the standard color temperature. If the color temperature difference is large, for example, more than 50K (this range can be freely set), then the collected R, G, and B stimulus values are compared with the standard tristimulus values. According to the comparison result, the driving current is adjusted. Here, the PWM adjustment mode can be adopted to adjust the duty ratio of the driving currents of the corresponding blue, cyan, and red LED light sources, and the color temperature of the lamp will change. Of course, other adjustment methods can be used, such as PFM adjustment or a combination of PFM and PWM adjustment. For example, comparing the collected R, G, and B tristimulus values with the standard tristimulus values, the R stimulation value is larger than the standard value, the G stimulation value is smaller than the standard value, and the B stimulation value is equal, then the PWM is passed. Adjusting the current duty ratio of the red LED light source (the fourth LED light source), increasing the current duty ratio of the cyan LED light source (the third LED light source), and maintaining the current of the blue LED light source (the second LED light source) The air ratio does not change and the color temperature of the luminaire changes. Then the color sensor collects the R, G, and B stimuli values of the mixed white light again, and feeds back the collected tristimulus values back to the MCU, and so on, until the actual color temperature of the collected light source is within a reasonable range of the standard color temperature (up and down △) Within the T range), the color temperature of the light source is stabilized.

Of course, in the working process, if the user wants to reset the color temperature file, when re-initializing, first adjust to the corresponding color temperature file, then the control circuit re-receives the new color temperature file data, and re-determines the mixing under the color temperature file. The standard stimulus values of red, green and blue light in white light are then subjected to the above closed loop control.

In the light distribution scheme of the specific embodiment, among the four light sources participating in the mixed light, only one LED chip is coated with a phosphor to generate excitation light, and the other three LED light sources are directly illuminated by the LED chip, and are not involved on the chip. The phosphor coating is a simple LED chip that participates in the light mixing, so it can be regarded as the corresponding color of the three colors of RGB, and the above feedback adjustment is realized, thereby ensuring that the LED lamp still has a stable color temperature after being used for a long time.

The above is a further detailed description of the present invention in connection with the specific preferred embodiments, and the specific embodiments of the present invention are not limited to the description. It will be apparent to those skilled in the art that <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt;

Claims

A high color rendering index LED light source module, characterized in that: the LED light source module comprises a first LED light source providing warm white light, a second LED light source providing blue light, a third LED light source providing cyan light and providing a fourth LED light source of red light; the first LED light source comprises a first blue LED chip having a peak wavelength of 442 to 450 nm, which is coated with a green phosphor having a peak wavelength of 525-540 nm and an orange of 580-600 nm The light phosphor provides a ratio of optical power of 0.02 to 0.04 in the warm white light, a light power ratio of 0.35 to 0.39, and an optical power ratio of 0.59 to 0.61. The second LED light source includes a second blue LED chip having a peak wavelength of 442 to 450 nm; the third LED light source includes a cyan LED chip having a peak wavelength of 490 to 500 nm; and the fourth LED light source includes a peak wavelength of 627 ～ 635nm red LED chip.
A high color rendering index LED lamp, comprising a heat sink, a reflector, a diffusion plate and a substrate on which the LED light source module is disposed, wherein the LED light source module comprises at least one set of LED light source modules, The LED light source module is the LED light source module according to claim 1, wherein the LED lamp further comprises four driving circuits and a control circuit; wherein the control circuit stores the luminous flux ratio of each LED light source and the white light after mixing Correspondence table between chromaticity parameters, wherein under the luminous flux ratio of each light source, each chromaticity parameter satisfies the following conditions: the color temperature is adjustable within the range of 2700K to 6500K, and the general color rendering index of the light source at each color temperature is Ra ≥ 95, The special color rendering index R9≥95, all color rendering indexes R1～R15 are ≥90, and the chromaticity difference ΔC<0.0054; the control circuit selects the corresponding luminous flux ratio of each LED light source according to the mixed color temperature obtained by the user. Determining the driving current of each LED light source according to the luminous flux ratio of each LED light source, and outputting the calculated driving current to the corresponding driving circuit respectively; the four driving circuits are respectively connected Drive current output to the respective LED light sources to drive the corresponding LED light sources to emit light.
The LED lamp of claim 2, wherein the LED lamp further comprises a color sensor, wherein the color sensor is configured to collect red, green and blue light in the mixed white light emitted by the LED light source module. Sensing the value, and outputting the collected value to the control circuit; the control circuit further storing a standard stimulus value of the red, green, and blue light corresponding to the mixed white light at each color temperature, and the control circuit further uses Perform the following feedback adjustments:

1) calculating a current actual color temperature value of the white light according to the collected stimulation value;

2) Compare the current actual color temperature value with the standard color temperature value to determine whether the difference between the two is less than or equal to ΔT, If yes, the driving current is kept unchanged; if not, proceeding to step 3); wherein, the standard color temperature value is a color temperature value of the mixed white light that the user needs to obtain, and ΔT is a difference threshold set by the user;

3) adjusting the fourth LED light source, the third LED light source and the second LED light source according to the comparison results of the collected red, green and blue light stimulus values and the standard stimulus values of red light, green light and blue light respectively The luminous flux ratio is adjusted to adjust the corresponding driving current; after the adjustment, return to step 1), and the adjustment process is repeated until the difference between the current actual color temperature value and the standard color temperature value is less than ΔT.
The LED lamp according to claim 2, wherein the plurality of LED light sources in the LED light source module are arranged in a circular shape, and the LED light sources providing different colors of light are spaced apart.
The LED lamp of claim 2, wherein the four drive circuits adjust the drive current by means of pulse width modulation (PWM).
The LED lamp of claim 2, wherein the reflector is a frosted reflector.
The LED lamp of claim 2, wherein the substrate is plated with a reflective film.
The LED lamp according to claim 2, wherein the diffusion plate is a PC diffusion plate, a PMMA diffusion plate or a frosted glass.