KR20120050781A - White light illumination device using light emitting diodes and color temperature control method - Google Patents

Abstract

PURPOSE: A lighting device including a light emitting diode and a color temperature controlling method using the same are provided to implement a sensitivity lighting function by controlling a color temperature and maintaining a high color rendering. CONSTITUTION: An operation mode selecting unit(110) includes a switching unit(112) and a mode signal generating unit(114). A light source unit(190) emits white light with a different CCT(Correlated Color Temperature). A lookup table stores a driving current value about each light source of the light source unit. A controller(130) generates a control signal corresponding to the intensity of the input current. A driver(170) supplies a driving current to each light source according to a control signal.

Description

White light illumination device using Light emitting diodes and Color temperature control method}

The present invention relates to a lighting device using a light emitting diode and a color temperature control method using the same, and more particularly, to a lighting device for emitting white light using a light emitting diode having various emission wavelengths and a color temperature control method using the same.

An illumination device including a light emitting diode (LED) has a low power consumption, a long life, can be installed in a narrow space, and provides vibration resistance.

With the recent development of semiconductor technology, the lifespan and efficiency of LED are gradually increasing, and it is expected to replace the existing lighting fixtures soon.

Long life LED lighting is expected to replace existing luminaires used in difficult-to-maintenance environment as soon as possible, and it is also possible to focus light in a high color rendering index and a narrow area. It is widely used as a light source for lighting and is expected to serve as a solution to solve the future energy crisis that gradually replaces all home lighting fixtures due to the low power consumption. In addition, these LED lights can also be used as a pick-up light, so that fishing boats no longer need to carry generators and fuels, which will greatly contribute to reducing the fuel consumption of ships. Technology.

In the method of implementing white light using an LED, a method of realizing white light at a package level by applying a phosphor to a UV LED or a blue LED, and red, blue and green color LED devices By adjoining, there is a tricolor LED system in which the light emission from each LED is mixed to realize white light.

In particular, the three-color LED method has a problem in that uniform color mixing, that is, white light close to natural light, is not realized due to different optical characteristics between respective light emitting devices, which causes a lot of technical difficulties in designing a lighting lamp.

In addition, in order to realize white light approaching to sunlight using commercially available LEDs, an appropriate combination of the number of LEDs having different colors and control of injection current is required. Especially in lighting systems, it is very important to reproduce colors that are very close to the colors perceived by the human eye under natural light, and the development of luminaires that emit light close to white light with excellent color reproducibility is a major factor for luminaire developers. R & D goal. Therefore, prior to product development, it is necessary to accurately analyze the optical characteristics and all-optical conversion characteristics of each light emitting device, and the design of the luminaire for maximizing color mixing and efficiency using the analysis results should be made.

As an index for analyzing the optical characteristics of the luminaire, there are a color rendering index (CRI) and a correlated color temperature (CCT).

CRI indicates the degree to which the color of the object is different when natural light having the same color temperature (similar to black body radiation) and artificially produced light are irradiated to the same object. It indicates how close the light is. As the CRI approaches 100, the light emitting device realizes white light close to natural light.

CCT refers to the temperature of a black body that radiates electromagnetic waves that are very similar when a light emitting body including a luminaire emits white light.

Research has shown that this CCT has a great effect on human emotion and brain waves. Therefore, the lighting suitable for various human activities can be realized through the control of the CCT and the light power of the light irradiated to the human environment, and can be further applied to psychiatric treatment. In addition, the strong light of a certain wavelength has a unique effect on the skin can be applied to dermatological treatment.

On the other hand, in the tricolor LED system, it is not easy to realize white light close to natural light. This is because the spectral region in which the LED emits light is very narrow compared to the case of using a fluorescent material, and thus it is difficult to include all the visible region.

In order to realize white light having a very high color rendering index using a single color LED, the visible light range is controlled by adjusting the center wavelength of the LED emitting a plurality of colors (3 or more colors) and the output light power or luminance from the LEDs, respectively. It is necessary to adjust the emission spectrum of the lamp in the whole. Since the relationship between the CRI value and the light power emitted from each LED has a non-linear relationship, it is almost impossible to experimentally obtain a desired color rendering index by controlling the current injected into each LED. It is almost impossible to do.

 Therefore, a procedure for designing an optimal spectrum through a mathematical simulation and implementing it experimentally is necessary before manufacturing a white LED luminaire through color mixing. The spectrum of each LED used in the simulation can use a Gaussian or Lorentzian line shape model.

1 is a graph showing the mixing of the spectrum of red, green and blue tricolor LEDs currently on the market. The three LEDs used here consist of a blue LED peaking around 460nm, a green LED peaking around 520nm and a red LED peaking around 630nm.

Referring to FIG. 1, when different injection currents are applied to each LED, the linewidths of the center wavelength and the emission wavelength of the LED do not change significantly. It is well known that the emission spectrum of an LED can be modeled using a Gaussian or Lorentian model. Therefore, the model for the mixing of the tricolor LED spectrum can be simplified, assuming that the line width and the center wavelength are not changed and only the output power of the LED is changed by the injection current. Finely varying center wavelengths and line widths can also be inserted into mathematical LED spectral models, which allows more accurate calculation of CRI and CCT of LED lamps according to injection current. However, this leads to a large number of parameters for optimizing the spectrum of white light, and therefore, it takes a lot of time to optimize using a computer program.

Referring to FIG. 1, when light emitted from red, green, and blue LEDs is synthesized, a spectrum showing a local maximum at three wavelengths is obtained as shown in the figure.

However, as shown, the intensity of the spectrum is weak between these peaks, resulting in a spectrum that differs from black body radiation as a whole.

Figure 2 is a color matching function (color matching function) by the CIE 1931 standard observer, a graph showing the basic shape by the wavelength of the human eye recognizes blue, green, red.

Referring to FIG. 2, when a color is synthesized using a light source having a spectrum close to a color matching function of blue, green, and red, the entire visible region may be evenly emitted, and lighting having excellent reproducibility may be designed for all colors. It can be seen that. However, currently commercially available LEDs have a much narrower line width than the color matching function.

In comparison with FIG. 1 and FIG. 2, in FIG. 1, the intensity of the spectrum is lowest in a specific section (S1: approximately 550 nm to approximately 590 nm) between the green wavelength band and the red wavelength band. Therefore, in the conventional tricolor LED system, it is difficult to realize white light that is close to natural light, that is, having high CRI.

As a result, conventional tricolor LEDs are limited in their application to a variety of products, and their application is difficult in lighting devices that require white light in close proximity to natural light.

On the other hand, when using a conventional tricolor LED device as a light source for illumination, an effective way to adjust the CCT has not been proposed. Even if the CRI provides high white light, high sensitivity lighting can be achieved by outputting white light of different CCTs depending on the taste and usage of the person.

Clear sky 12,000K Misty sky 9,500K Cloudy sky 7,000 K Bright sun 5,500K Sunrise and sunset 2 hours before and after 4,000K 1 hour before and after sunrise and sunset 3,500K At sunrise, sunset 3,100K At sunrise, at sunset 2,000 ~ 3,000K

Table 1 above shows the change in color temperature over time. As can be seen in Table 1, the solar CCT varies from 2000K to 12000K over time. Therefore, if the lighting can adjust the CCT of the white light as shown below, the human can feel the closest to the natural light, it can create a variety of atmospheres.

In addition, various research results on CCT suitable for human brain activity have been published, and if the CCT can be adjusted according to human learning, creative activity, and logical brain activity, it helps to generate EEG suitable for human activity. It can also increase the efficiency of.

 In addition, there is a need to use the white LED device for illumination to follow the day cycle of natural light by automatically or manually adjusting the CCT to a day cycle in order to provide a lamp that matches the human biorhythm.

In this way, if the CCT adjustment function is provided, in addition to the basic lighting function for illuminating the room, the emotional lighting that can produce a unique atmosphere can be realized. Emotional lighting through CCT control can also be applied to psychotherapy, such as stabilizing a person's psychological state.

These functions can have a great degree of freedom in lighting design due to the use of LED lighting.

However, when only the packaged white LED is used, high CRI can be obtained, but control of the CCT is difficult. In addition, since the optical power is distributed over a very broad spectrum, the all-optical conversion efficiency is lowered.

In addition, the conventional three-color LED system only performs a simple function of lighting control according to the ambient light, there is a problem that is easy to control the CCT, but it is very difficult to realize a high CRI (> 90).

Accordingly, an object of the present invention is to provide a lighting device using an LED that can maintain a high CRI to provide a white light similar to natural light, and at the same time can perform the function of emotional lighting through CCT adjustment.

In addition, another object of the present invention is to provide a color temperature control method using the lighting device that can maintain a high CRI, and at the same time can perform the function of the emotional lighting through the control of the CCT and the amount of light.

According to an aspect of the present invention, a lighting apparatus according to an aspect of the present invention has a plurality of operation modes defined according to a use time or a user environment, and generates a different driving current for each operation mode in response to a control signal. And a light source unit having a predetermined color rendering index and emitting white light having a different CCT for each of the operation modes according to the different driving currents within a preset color temperature range. do. The light source unit may include a first light emitting device having a peak wavelength of about 465 nm to about 477 nm, a second light emitting device having a peak wavelength of about 519 nm to about 537 nm, and a third having a peak wavelength of about 582 nm to about 598 nm. And a fourth light emitting device having a peak wavelength of approximately 618 nm to approximately 636 nm.

According to another aspect of the present invention, a lighting apparatus includes a driving driver that defines a plurality of operation modes according to a use time or a user environment, generates a different driving current for each operation mode, and has a preset color rendering index, and a preset color temperature. And a light source unit emitting white light having a different color temperature for each operation mode according to the different driving currents within a range of correlated color temperature. The light source unit may include a first light emitting device having a peak wavelength of about 465 nm to about 477 nm, a second light emitting device having a peak wavelength of about 519 nm to about 537 nm, and a third light emission having a peak wavelength of about 554 nm to 566 nm. Device and a fourth light emitting device having a peak wavelength of approximately 618 nm to approximately 636 nm.

According to another aspect of the present invention, a lighting device includes a driving driver defining a plurality of operation modes divided according to time or a user environment, and generating a different driving current for each operation mode, and a color rendering index of natural light (Color Rendering Index) It includes a light source unit having a predetermined color rendering index close to), and emits white light having a different color temperature for each operation mode according to the different driving current within a predetermined color temperature (Correlated Color Temperature) range. Here, the light source unit has a first light emitting device having an x chromaticity value of about 0.279 to about 0.3531 and a y chromaticity value of about 0.297 to about 0.3605, a second light emitting device having a peak wavelength of about 465 nm to about 477 nm, and about 618 nm. To a third wavelength having a peak wavelength of approximately 636 nm.

According to another aspect of the present invention, there is provided a method of controlling color temperature, in which a plurality of operation modes are defined according to a use time or a user environment, and storing a ratio of a reference current input to each LED optimized for each operation mode in advance. And generating a different driving current for each operation mode according to the light intensity desired by the user, and referring to the ratio of the pre-stored reference current, and different color temperatures for each operation mode according to the different driving current. And emitting white light having the same. The emitting white light may include an emission spectrum of the first light emitting device having an x chromaticity value of about 0.279 to about 0.3531 and a y chromaticity value of about 0.297 to about 0.3605, and a peak wavelength of about 465 nm to about 477 nm. And emitting the white light in which the emission spectrum of the second light emitting device and the emission spectrum of the third light emitting device having a peak wavelength of about 618 nm to about 636 nm are mixed.

As described above, according to the lighting apparatus using the light emitting diode and the color temperature control method using the same, the high color rendering index is maintained to provide white light similar to natural light by using at least three light emitting elements, and at the same time, the function of the emotional lighting through color temperature adjustment Can be performed.

1 is a graph showing the mixing of the spectrum of red, green and blue tricolor LEDs currently on the market.
Figure 2 is a color matching function (color matching function) by the CIE 1931 standard observer, a graph showing the basic shape by the wavelength of the human eye recognizes blue, green, red.
3 is a block diagram showing a lighting apparatus according to a preferred embodiment of the present invention.
FIG. 4 is a CIE-1931 diagram illustrating white light characteristics of the white LED device when the light source unit illustrated in FIG. 3 includes a white LED device, a blue LED device, and a red LED device.
FIG. 5 is a graph showing the emission spectrum of the white LED device having the chromaticity value shown in FIG. 4 as a function of wavelength.
FIG. 6 is a graph showing the emission spectra of the white, blue, green, yellow and red LED devices shown in FIG.
FIG. 7 is a graph showing emission spectra of each LED device and a mixed spectrum of white light implemented by each LED device in a second operation mode (Mode 2) according to an embodiment of the present invention.
FIG. 8 is a flowchart illustrating a color temperature control method using the lighting apparatus illustrated in FIG. 3.

The term "line width" as used throughout this specification is used to describe the width of the emission spectrum of a light emitting device. The emission profile of the light source has the shape of a Gaussian (or Lorentz) curve as a function of wavelength, as described above. This line width is an indicator used to compare curves with different emission spectra, and is defined as the width across a point at which the curve is half the peak or maximum. The term line width is sometimes used as the term full width at half maximum (FWHM).

The present invention provides a high CRI close to the CRI of natural light that cannot be obtained in the conventional three-color LED system, and at the same time provides the function of emotional lighting through the control of the CCT.

In particular, the present invention provides a lighting device and a method for controlling color temperature using the same, which maintains a CRI of 90 or more, preferably 95 or more, and simultaneously controls the CCT from about 2000K to about 12000K, preferably about 3500K to about 6500K. .

As shown in FIG. 1, in the existing tricolor LED system, the intensity of the spectrum is very low in a specific section (S1: about 550 nm to about 590 nm) between the green wavelength band and the red wavelength band. As a result, it is difficult to realize white light in which the CRI maintains 95 or more in the conventional tricolor LED system. In order to solve this problem, the present invention increases the intensity of the spectrum in the specific section S1, thereby providing white light close to natural light.

The present invention includes at least three light emitting devices that form a specific wavelength band proposed by the applicant in order to increase the spectral intensity in the specific section S1, thereby increasing the spectral intensity in the specific section S1. As a result, overall CRI is improved.

In addition, in the present invention, by adding three primary colors including R, G1, and B and a G2 or Y LED having a relatively large line width, it is helpful to improve the CRI.

In particular, by adopting a light emitting device that emits red light having a wide line width to a red LED having a narrow line width compared to other color LEDs, improves the optical characteristics of red light having a narrow line width (LW1, approximately 20nm) compared to other lights do. As a result, higher CRI can be obtained.

In the present invention, LEDs having a wide line width can be selected and used individually, or a plurality of LEDs emitting light of the same color is used for lighting, so that each LED has a certain dispersion in the center emission wavelength. . Therefore, it is possible to improve (wide) the line width of the LED through a combination of LEDs with high dispersion in a certain range.

In addition, the present invention is limited to the peak wavelength range of the specific range proposed by the applicant of the four light-emitting elements consisting of one (G2 or Y) in addition to the three primary colors (R, G1, B), 90 or more, Preferably it can provide very high CRI of 95 or more.

In addition, the present invention is proposed to automatically adjust the CCT within the range of about 3500K to about 6500K to achieve the function of the emotional lighting.

Therefore, in the lighting apparatus of the present invention and the color temperature control method using the same, by achieving a CRI of 90 or more basically, it is possible to provide white light close to natural light, and at the same time provide a function of emotional lighting through CCT adjustment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Shapes and sizes of the respective graphs provided as respective components or simulation results in the drawings may be exaggerated for clarity.

3 is a block diagram showing a lighting apparatus according to a preferred embodiment of the present invention.

Referring to FIG. 3, the lighting apparatus 100 according to an exemplary embodiment of the present invention may include an operation mode selector 110, a controller 130, a look-up table 150, a driving driver 170, and the like. It includes a light source unit 190.

The operation mode selector 110 generates a mode selection signal MOD according to the operation mode selected by the user and outputs the mode selection signal MOD to the controller 130. The operation mode of the light source unit 190 is determined according to the operation mode selected by the user. Here, the operation mode refers to a step of dividing a range of CCTs provided by the light source unit 190 to emit white light having a desired CCT.

The scope of the CCT may be divided according to a user's use time or a user's use environment.

For example, when the range of the CCT is divided according to the user's usage time, in the first operation mode (Mode 1), the light source unit is configured such that the operation mode selector 110 emits approximately 3500K of white light similar to natural light in the morning time zone. An operation mode of 190 is set.

In the second operation mode (Mode 2), an operation mode of the light source unit is set to emit white light of approximately 6500K, which is similar to natural light at lunch time.

In the third operation mode (Mode 3), the operation mode of the light source unit 190 is set to emit approximately 4500K white light similar to natural light in the evening time zone.

There are many cases where the scope of the CCT is divided according to the user's usage environment. For example, when the user reads, listens to music, the range of the CCT may be divided according to the user's use environment such as the learning environment for each subject.

When the range of the CCT is classified according to the study atmosphere for each learning subject, the operation mode of the light source unit 190 may be set as follows.

In the first operation mode (Mode 1), the operation mode selector 110 emits approximately 4500K of white light, which is known to be suitable for the user to require high concentration, to acquire a large amount of information, and to memorize. The operation mode of 190 is set.

In the second mode of operation (Mode 2), the user is set to emit approximately 6500K of white light, which is known to stimulate the brain waves generated in the course of excellent logical thinking.

In the third operation mode (Mode 3), the operation mode of the light source unit 190 can be set to emit approximately 3500K of white light which simulates a comfortable atmosphere known to be suitable for the user to relax.

In the present embodiment, three operation modes in which the number of operation modes are configured as the first to third operation modes are described. However, the number of operation modes and the CCT in each operation mode may be adjusted as necessary.

In the present embodiment, the operation mode is described as being manually selected by the user, but may be automatically selected. In this case, it will be apparent to those skilled in the art that the operation mode may be automatically adjusted for each time period from sunset to sunset using a counter or timer.

In the present embodiment, description will be made on the assumption of operation modes divided according to time.

The operation mode selector 110 includes a switching unit 112 and a mode signal generator 114. The user selects a desired operation mode through the switching unit 112. Here, the switching unit 102 may be implemented in various forms such as a button form, a sliding form, a rotary switch form. The mode signal generator 114 outputs a mode selection signal MOD that can be processed by the controller 130 according to the operation mode selected by the switching unit 112.

The controller 130 generates a control signal corresponding to the selected operation mode in response to the mode selection signal MOD and outputs the control signal to the driving driver 170. In this case, the controller 130 receives the preset intensity value corresponding to the CCT value required in the selected operation mode by referring to the lookup table 150, and the controller corresponds to the input preset intensity value. Output a control signal. Here, the control signal may be a pulse width modulated (PWM) signal, an amplitude modulated signal, or an analog signal. In the present embodiment, the control signal is limited to the PWM signal.

The lookup table 150 stores a ratio of reference current values corresponding to the CCT required in the selected operation mode in advance. The ratio of the reference current values stored in the lookup table 150 may include a first reference current value Ib corresponding to blue light, a second reference current value Ig corresponding to green light, and a third reference current value corresponding to yellow light. The ratio of the fourth reference current value Ir corresponding to (Iy) and the red light is meant. These ratios of reference current values are classified into operation modes as shown in Table 1 below and stored in the lookup table 150, and the ratio of reference current values optimized to provide a CCT required in a corresponding operation mode. Each reference current value is experimental data previously measured by the designer.

Iw (white light) Ib (blue light) Ig (green light) Iy (yellow light) Ir (red light) Mode 1 3 mA 2 mA 6 mA 3 mA 8 mA Mode 2 5 mA 1 mA 8 mA 5 mA 7 mA Mode 3 4 mA 3 mA 7 mA 9 mA 6 mA

Accordingly, the controller 130 may correspond to the first PWM signal PWM-B corresponding to the first reference current value Ib and the second reference current value Ig in response to the mode signal MOD. The third PWM signal PWM-Y corresponding to the PWM signal PWM-G, the third reference current value Iy, and the fourth PWM signal PWM-R corresponding to the fourth reference current value Ir The PWM signal is generated and output to the driving driver 170.

The driving driver 170 generates a driving current corresponding to the selected operation mode in response to the PWM signal, and outputs the driving current to the light source unit 190. That is, the driving driver 170 generates driving currents DI having different strengths of currents for each time zone in order to create a natural light atmosphere in the morning, lunch, or evening time zone.

In detail, the driving driver 170 may include a first driving current DI1 corresponding to the first PWM signal PWM-B and a second driving current DI2 corresponding to the second PWM signal PWM-G. The driving current DI including a third driving current DI3 corresponding to the third PWM signal PWM-Y and a fourth driving current DI4 corresponding to the fourth PWM signal PWM-R. ) Is generated and output to the light source unit 150.

The light source unit 150 provides white light having a CCT corresponding to an operation mode selected by a user in response to the driving current DI provided from the driving driver 170. That is, the light source unit 150 emits white light having a CCT corresponding to an operation mode selected by a user according to a combination of the first to fourth driving currents DI1, DI2, DI3, and DI4 provided from the driving driver 170. to provide.

In detail, the light source unit 190 may include a blue LED device 191 emitting blue light, a green LED device 193 emitting green light, a yellow LED device 195 emitting yellow light, and a red LED device emitting red light. (197).

The blue LED device 191 emits blue light having a first peak wavelength range in response to a first driving current DI1, and the first peak wavelength range is about 465 nm to about 477 nm in this embodiment.

The green LED element 193 emits green light having a second peak wavelength range longer than the first peak wavelength range in response to a second driving current DI2. In the present embodiment, the second peak wavelength range is It is about 519 nm-537 nm.

The yellow LED element 195 emits yellow light having a third peak wavelength range longer than the second peak wavelength range in response to a third driving current DI3, and in the present embodiment, the third peak wavelength range. Is approximately 582 nm to approximately 598 nm.

The red LED element 197 emits red light having a fourth peak wavelength range longer than the third peak wavelength range in response to a fourth driving current DI5. In the present embodiment, the fifth peak wavelength range is About 618 nm to about 636 nm. Here, when the red LED element 197 is further limited to the fifth peak wavelength range having a range of 618 nm to 624 nm, the applicant confirms that the line width of the conventional red light of approximately 20 nm (LW1 in FIG. 1) becomes larger. Could. Therefore, the fourth peak wavelength range of the red LED device 199 preferably has a range of 618 nm to 624 nm.

By combining LED devices having a specific range of wavelengths as described above, the Applicant was able to confirm that white light capable of maintaining a CRI of 90 or more, preferably 95, can be realized, and also in the range of 3500K to 6500K. It was confirmed that the white light having the CCT can be implemented.

Meanwhile, the lighting apparatus according to the exemplary embodiment of the present invention illustrated in FIG. 3 describes a light source unit 190 including a blue LED element, a green LED element, a yellow LED element, and a red LED element, but the present applicant has the yellow LED. By replacing the device with a green LED device having a peak wavelength range of 554 nm to 566 nm, the same effect was obtained.

Therefore, in the lighting apparatus according to another embodiment of the present invention, the light source unit includes a blue LED element, a first green LED element, a second green LED element, and a red LED element, and the peak wavelength range of the second green LED element is 554 nm to It is limited to 566 nm. The remaining blue LED elements, the first green LED elements and the red LED elements are the same as the respective peak wavelength ranges of the blue LED element 191, the green LED element 193, and the red LED element 197 described with reference to FIG. 3. .

In addition, in the present invention, basically, using four light emitting elements (B, G, Y, R or B, G1, G2, R), a CRI of 90 or more, preferably 95, and a CCT in the range of 3500K to 6500K are used. Although the white light is implemented, the applicant can confirm that the control range of the high CRI and CCT to be achieved in the present invention can be achieved by using a light source unit including three light emitting devices. In this case, the light source unit illustrated in FIG. 3 includes three light emitting devices each including a white LED device, a blue LED device, and a red LED device. The white LED device emits white light whose chromaticity values exist within a region limited on the CIE-1931 plot by the x specific chromaticity value of the blackbody trajectory and the y specific chromaticity value of the second specific range.

4 is a CIE-1931 diagram showing white light characteristics of the white LED device when the light source unit shown in FIG. 3 is composed of a white LED device, a blue LED device, and a red LED device, and FIG. 5 is shown in FIG. It is a graph showing the emission spectrum of a white LED device having a chromaticity value as a function of the wavelength.

As shown in FIG. 4, the white LED device has an x chromaticity value of the first specific range of approximately 0.279 to approximately 0.3531 and a y chromaticity value of the second specific range of approximately 0.297 to approximately 0.3605. The white LED device emits white light maintaining a CRI of approximately 90.

In particular, as shown in FIG. 5, the white LED device is characterized by a very strong blue emission of about 5500K to about 8800K CCT. The white LED device used here is an LED made by emitting a fluorescent material to a LED emitting a spectrum in the blue or ultraviolet region to emit light in a wide visible light region, and its CCT and CRI are determined according to the fluorescent substance. Therefore, the LED made by this method is impossible to control the CCT and CRI according to the external driving method. However, by placing the LED corresponding to R G B Y around the white LED, the CCT can be adjusted in a very wide range through mixing.

In particular, when the light source unit according to another embodiment of the present invention is made of the above-described white LED device, blue LED device and red LED device, the applicant has a CCT range of 2000K ~ 20000K, 57 ~ 92 at less than 5000K It was confirmed that the CRI and the white light having a CRI of 77 to 92 at 5000K or more were possible.

Meanwhile, when the light source unit is made of a white LED device, a blue LED device, and a red LED device according to another embodiment of the present invention, the blue LED device and the red LED device are the blue LED device 191 and the red light described with reference to FIG. 3. Each peak wavelength range of the LED element 197 has the same peak wavelength range.

FIG. 6 is a graph showing the emission spectra of the white, blue, green, yellow and red LED devices shown in FIG.

In FIG. 6, first to fifth graphs C1, C2, C3, C4, and C5 are shown. The first graph C1 is a graph showing the emission spectrum of the white LED element 191, the second graph C2 is a graph showing the emission spectrum of blue light having a peak wavelength of approximately 470 nm, for example, and the third graph ( C3) is, for example, a graph showing an emission spectrum of green light having a peak wavelength of approximately 527 nm, and a fourth graph (C4) is a graph showing, for example, an emission spectrum of yellow light having a peak wavelength of approximately 590 nm, and a fifth graph (C5). ) Is a graph showing an emission spectrum of red light having, for example, a peak wavelength of approximately 630 nm. That is, the embodiment implements the white light using the light source unit consisting of W B G Y R.

FIG. 7 is a graph showing emission spectra of each LED device and a mixed spectrum of white light implemented by each LED device in a second operation mode (Mode 2) according to an embodiment of the present invention.

Referring to FIG. 7, the wavelengths of the first to fifth graphs C1, C2, C3, C4, and C5 of FIG. 7 are the same as those shown in FIG. 6, and the intensity of each light source is different. The fifth graph C1, C2, C3, C4, C5 is a graph showing emission spectra of each LED device for forming white light having a CRI of approximately 95, and a second mode of operation, that is, approximately 6500K. C6) is a graph showing a mixed spectrum of white light formed by mixing the first to fifth graphs C1, C2, C3, C4, and C5.

As can be seen from Figure 7, the lighting apparatus according to the embodiment of the present invention shows an even spectral intensity in the entire wavelength band. Therefore, it is possible to provide a high CRI basically.

Meanwhile, the light emitting device according to the embodiment of the present invention describes a light source unit 190 including a white LED device, a blue LED device, a green LED device, a yellow LED device, and a red LED device, but the present applicant has described the yellow LED device. By replacing with another green LED device having a peak wavelength range of 554 nm to 566 nm, the same effect was obtained.

In summary, an embodiment of the present invention implements white light having a CRI of 95 or more and a CCT ranging from 3500K to 6500K using a light source unit consisting of B, G, Y, and R having a specific range of wavelength bands presented by the applicant. It was.

In another embodiment of the present invention by using the light source unit consisting of B, G1, G2, R having a specific range of the wavelength band proposed by the applicant to implement white light having a CRI of 95 or more and CCT range of 3500K ~ 6500K.

In another embodiment of the present invention, a white light having a high CRI and a wide range of CCT is realized by using a light source unit consisting of W, R, and B. In particular, in this case, the present applicant has a CCT range of 2000K ~ 20000K, it was confirmed that the implementation of the white light having a CRI of 57 ~ 92 and less than 5000K, CRI of 77 ~ 92 at 5000K or more.

In another embodiment of the present invention, the white LED having a specific range of wavelength band proposed by the applicant and a light source unit consisting of B, G, Y, and R, and white light having a CRI of 90 or more and a CCT in the range of 3500K to 15000K. Was implemented.

8 is a flowchart illustrating a CCT control method using the lighting apparatus illustrated in FIG. 3.

Referring to FIG. 8, first, a ratio of a reference current value input to each LED optimized for each operation mode by a designer is stored in the form of a lookup table (S810). The ratio of the reference current values is data previously learned by the user, and the respective reference current values are experimental data previously measured by the designer.

Next, an operation mode is selected (S820). That is, the operation mode is manually selected by the user according to the user's usage time or the user's usage environment. In particular, when the operation mode is selected according to the user's use time, the operation mode may be automatically selected using a timer or the like.

Subsequently, the input current input to each LED device is adjusted according to the selected operation mode by referring to the ratio of the reference current values stored in the form of a look-up table by the controller 130 and the driving driver 170 shown in FIG. S830).

Finally, white light having an optimized color temperature is emitted in the corresponding operation mode selected according to the adjusted input current (S840).

Through the embodiments described so far, the lighting device and the color temperature control method using the same can provide a high CRI to provide white light similar to natural light, and at the same time adjust the CCT according to the user's use time or environment, Can perform the function of.

As described above, the present invention is not limited to the above-described embodiments and the accompanying drawings, and is defined by the appended claims, and is defined in various forms within the scope of the present invention. It will be apparent to those skilled in the art that substitutions, modifications, and variations are possible.

Claims (4)

A light source unit including three or more light sources each having a different wavelength, and emitting white light having a different CCT (Correlated Color Temperature) according to a driving current supplied to each of the light sources;
According to a plurality of operation modes defined on the basis of the CCT period of the white light, a lookup in which the driving current value for each light source of the light source unit is stored so that the light source unit emits white light having a CCT of the interval defined for each operation mode Table,
A controller configured to read an intensity value of the input current corresponding to a selected operation mode among the plurality of operation modes with reference to the lookup table, and generate a control signal corresponding to the read intensity value of the input current;
A driving driver for supplying the driving current to each of the light sources according to the control signal
Including,
And the light source unit emits white light having a CCT of 3500K to 20000K according to the driving current while maintaining a color rendering index (CRI) of 90 or more. The method of claim 1, wherein the light source unit
A first light emitting device having a peak wavelength of 465 nm to 477 nm;
A second light emitting device having a peak wavelength of 519 nm to 537 nm;
A third light emitting device having a peak wavelength of 582 nm to 598 nm; And
Lighting device comprising a fourth light emitting element having a peak wavelength of 618nm to 636nm. Lighting device. A light source unit including three or more light sources each having a different wavelength, and emitting white light having a different CCT (Correlated Color Temperature) according to a driving current supplied to each of the light sources;
A controller for generating a control signal for each operation mode such that a driving current having a predetermined value for each of the light sources is supplied to each of the light sources for each of a plurality of operation modes defined based on the CCT section of the white light;
A driving driver for supplying the driving current to each of the light sources according to the control signal,
The light source unit includes:
A first light emitting device having an x chromaticity value of 0.279 to 0.3531 and a y chromaticity value of 0.297 to 0.3605;
A second light emitting device having a peak wavelength of 465 nm to 477 nm; And
And a third light emitting element having a peak wavelength of 618 nm to 636 nm. The illuminating device according to claim 8, wherein the first light emitting device is a white light emitting device, the second light emitting device is a blue light emitting device, and the third light emitting device is a red light emitting device.

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