TWM666178U - White light emitting chip and lighting device - Google Patents

Abstract

A white light emitting crystal and a lighting device, the lighting device comprising a light source unit and a control unit. The light source unit comprises three white light emitting crystals. Each white light emitting crystal comprises a first, a second, and a third light emitting diode element and three fluorescent layers. The first light emitting diode element can emit a first blue light with a wavelength between 410 and 450 nanometers. The second light emitting diode element can emit a second blue light with a wavelength between 450 and 470 nanometers. The third light emitting diode element can emit a third blue light with a wavelength between 460 and 490 nanometers. The fluorescent layers can be excited by the first blue light, the second blue light and the third blue light respectively, and the mixed light after the excitation appears as white light with blue-green light, so that each white light emitting crystal grain generates white light, thereby achieving the effect of simulating sunlight.

Description

White light emitting chip and lighting device

This new invention relates to a light-emitting crystal and a lighting device, in particular to a white light-emitting crystal that can emit white light and a lighting device with adjustable color temperature.

Refer to Figure 1, which shows the spectrum of white light emitted by a general white light emitting crystal. The definition of white light is that its spectrum is continuous, and its spectrum range is 380nm~780nm, and its luminous color may change from reddish, yellowish to bluish depending on the color temperature. Since the white light emitted by a general white light emitting crystal lacks blue-green light (as indicated by the arrows in Figure 1), the color rendering index R9 and R12 usually do not exceed 90, and it cannot completely simulate sunlight. Therefore, how to make the white light emitted by a general white light emitting crystal simulate real sunlight is the focus of current white light emitting crystal developers.

Referring to FIG. 2 , a general lighting device is usually provided with two groups of light-emitting chips with different color temperatures and adjustable brightness. Among them, the coordinates of one of the light-emitting chips with a lower color temperature in the CIE chromaticity diagram shown in FIG. 2 are defined as a low color temperature coordinate 110; the coordinates of the other light-emitting chip with a higher color temperature in the CIE chromaticity diagram shown in FIG. 2 are defined as a high color temperature coordinate 120. The light emitted by each of the light-emitting chips after mixing is the light emitted by the lighting device. By adjusting the brightness of the light-emitting chips separately, the color temperature of the mixed light source (i.e., the light emitted by the lighting device) can be changed on the line connecting the low color temperature coordinate 110 and the high color temperature coordinate 120. However, the line connecting the low color temperature coordinate 110 and the high color temperature coordinate 120 still deviates from the black body radiation 40 representing sunlight in FIG. 2 . That is to say, the color temperature of the light emitted by a general lighting device still has a significant gap with the color temperature of real sunlight.

Therefore, the purpose of this invention is to provide a white light emitting crystal particle that can solve at least one of the above problems.

Therefore, the novel white light emitting crystal chip includes a base plate, a first light emitting diode element, a second light emitting diode element, a third light emitting diode element and three fluorescent layers. The first light emitting diode element is arranged on the base plate and can emit a first blue light with a wavelength between 410nm and 450nm. The second light emitting diode element is arranged on the base plate and can emit a second blue light with a wavelength between 450nm and 470nm. The third light emitting diode element is arranged on the base plate and can emit a third blue light with a wavelength between 460nm and 490nm. The fluorescent layers cover the surfaces of the first light emitting diode element, the second light emitting diode element and the third light emitting diode element respectively. When the fluorescent layers are irradiated by the first blue light, the second blue light and the third blue light respectively, the fluorescent layers will be excited to make the white light emitting crystal generate white light.

In some embodiments, the first blue light emitted by the first LED element has a color temperature between 2700K and 7500K, the second blue light emitted by the second LED element has a color temperature between 2700K and 7500K, and the third blue light emitted by the third LED element has a color temperature between 2700K and 7500K.

In some embodiments, the white light generated by the white light emitting crystal has a color rendering index R9 greater than 91 at an ambient temperature between 30°C and 90°C.

In some embodiments, the white light generated by the white light emitting crystal has a color rendering index R12 greater than 91 at an ambient temperature between 30°C and 90°C.

Another purpose of the present invention is to provide a lighting device that can provide a basic light source close to blackbody radiation.

Therefore, the novel lighting device includes a light source unit and a control unit. The light source unit includes at least three of the aforementioned white light emitting crystals. The white light generated by the white light emitting crystals has color coordinates corresponding to a first coordinate, a second coordinate and a third coordinate in a CIE chromaticity diagram, respectively. The relevant color temperatures of the first coordinate, the second coordinate and the third coordinate are different from each other. The line connecting the first coordinate, the second coordinate and the third coordinate forms two intersections with a black body radiation. The line connecting the first coordinate, the second coordinate and the third coordinate surrounds and defines a dimming area. The dimming area includes a portion of the black body radiation, and the corresponding color coordinate of the light source after mixing of the light source unit in the CIE chromaticity diagram is defined as a mixed light coordinate. The control unit is electrically connected to the light source unit to output current to the white light emitting chips to control their brightness changes respectively, so that the mixed light coordinates move in the dimming area.

In some embodiments, at least two of the first coordinate, the second coordinate, and the third coordinate are not located on the blackbody radiation.

In some implementations, the first coordinate, the second coordinate, and the third coordinate are not located on the blackbody radiation.

In some embodiments, the line connecting the first coordinate, the second coordinate and the third coordinate forms two intersections with the black body radiation. The color temperature of one of the intersections is not higher than 1800K, and the color temperature of the other intersection is not lower than 10000K.

In some embodiments, the line connecting the first coordinate and the third coordinate forms two intersections with the black body radiation. The color temperature of one of the intersections is not higher than 1800K, and the color temperature of the other intersection is not lower than 10000K.

In some implementations, the associated color temperature of the first coordinate is between 1800 and 2600K.

In some implementations, the associated color temperature of the second coordinate is between 2600 and 4500K.

In some implementations, the associated color temperature of the third coordinate is between 6500 and 10000K.

In some embodiments, the lighting device further includes a substrate. The white light emitting chips are arranged alternately on the substrate.

In some embodiments, the light source unit further includes a red light group, a green light group, and a blue light group electrically connected to the control unit and used to emit monochromatic light. The red light group, the green light group, and the blue light group respectively receive the current output by the control unit to change their brightness.

In some embodiments, the corresponding color coordinates of the red light group, the green light group, and the blue light group in the CIE chromaticity diagram are defined as a red light coordinate, a green light coordinate, and a blue light coordinate, respectively. The connection line of the red light coordinate, the green light coordinate, and the blue light coordinate surrounds and defines a light mixing area, and the area of the light mixing area is larger than the area of the dimming area.

The effect of the present invention is that the first light-emitting diode element, the second light-emitting diode element and the third light-emitting diode element emit three kinds of blue light with wavelengths between 410nm and 450nm, between 450nm and 470nm and between 460nm and 490nm, so that the mixed light of the excited fluorescent layers can appear as white light with blue-green light, so as to achieve the effect of simulating sunlight. In addition, the white light generated by the white light emitting crystals includes part of the black body radiation in the dimming area of the CIE chromaticity diagram, so that the light mixing coordinates corresponding to the light source unit after light mixing can be close to the black body radiation as the brightness of the white light emitting crystals changes, so as to achieve the effect that the light emitted by the lighting device is similar to sunlight at different color temperatures.

Refer to Figures 3 and 4, which are an embodiment of the novel lighting device. The lighting device includes a light source unit 1, a control unit 2 electrically connected to the light source unit 1, and a substrate 3 on which the light source unit 1 is mounted. The lighting device can be any type of lighting device, such as a photographic lamp, a ceiling-mounted recessed lamp, a table lamp, a plant growth lamp, etc.

The light source unit 1 includes a first white light group 11, a second white light group 12 and a third white light group 13 that can emit white light with different Correlated Color Temperatures (CCT). The first white light group 11, the second white light group 12 and the third white light group 13 each include a plurality of white light emitting crystal grains 10. The white light emitting crystal grains 10 of the first white light group 11, the white light emitting crystal grains 10 of the second white light group 12 and the white light emitting crystal grains 10 of the third white light group 13 are alternately arranged on the substrate 3 and are arranged in a slightly circular shape as a whole. The staggered arrangement of the white light emitting crystals 10 of the first white light group 11, the second white light group 12 and the third white light group 13 can make the light source after color mixing uniform, but in other embodiments, the arrangement and shape of the light source unit 1 are not limited to a specific form. And the first white light group 11, the second white light group 12 and the third white light group 13 can also each include only one white light emitting crystal 10, depending on actual needs.

5, each of the white light emitting chips 10 includes a base plate 101, a first light emitting diode element 102, a second light emitting diode element 103 and a third light emitting diode element 104 disposed on the base plate 101, and three fluorescent layers 105 respectively covering the first light emitting diode element 102, the second light emitting diode element 103 and the third light emitting diode element 104. The first light emitting diode element 102, the second light emitting diode element 103 and the third light emitting diode element 104 are all basic light emitting diode (Light Emitting Diode, referred to as: LED) package components. Specifically, the first LED element 102 can emit a first blue light (not shown) with a wavelength between 410nm and 450nm when a voltage is applied, and the color temperature of the first blue light emitted by the first LED element 102 is between 2700K and 7500K. The second LED element 103 can emit a second blue light (not shown) with a wavelength between 450nm and 470nm when a voltage is applied, and the color temperature of the second blue light emitted by the second LED element 103 is between 2700K and 7500K. The third LED element 104 can be applied with a voltage to emit a third blue light (not shown) with a wavelength between 460nm and 490nm, and the color temperature of the third blue light emitted by the third LED element 104 is between 2700K and 7500K.

The fluorescent layers 105 are, for example, structures composed of fluorescent powders of different colors, and the composition or composition ratio of the fluorescent layers 105 will vary according to the wavelength of blue light emitted by the corresponding light-emitting diode elements, and can be adjusted according to needs.

Referring to FIG. 6 , when the fluorescent layers 105 are irradiated by the first blue light, the second blue light, and the third blue light, the fluorescent layers 105 are excited to generate light of different colors. The light of different colors generated by the fluorescent layers 105 are mixed to present white light with blue-green light, so that the white light emitting crystal grain 10 generates white light and simulates sunlight.

The white light generated by the white light emitting crystal 10 has a very high color rendering index (i.e., the quantitative degree of a light source's ability to present the color of a real object, in English: Color Rendering Index, abbreviated as: CRI). Specifically, the color rendering index R1~R15 of the white light generated by the white light emitting crystal 10 is greater than 90, and in particular, the color rendering index R9 and R12 of the white light generated by the white light emitting crystal 10 are both greater than 93 when the relevant color temperature is 5886K, which can improve the color reproduction. In this embodiment, the measured values of the color rendering index Ra, R1~R15 of the white light emitting crystal 10 when the relevant color temperature is 5886K are shown in Table 1 below.

Referring to FIG. 7 , the relative color temperature changes of the white light emitting die 10 and a general white light emitting die at different ambient temperatures ( _TP ) are shown. The relative color temperature changes of the white light emitting die 10 are shown by the solid line in FIG. 7 , while the relative color temperature changes of the general white light emitting die are shown by the dotted line in FIG. 7 . FIG. 7 shows that the relative color temperature of the white light emitting die 10 is less significantly affected by the ambient temperature than that of the general white light emitting die.

Refer to Figure 8, which shows the color rendering index R9 changes of the white light emitting crystal grain 10 and general white light emitting crystal grains in different ambient temperatures. The color rendering index R9 change of the white light emitting crystal grain 10 is represented by the solid line in Figure 8, and the color rendering index R9 change of the general white light emitting crystal grain is represented by the dotted line in Figure 8. Figure 8 shows that the color rendering index R9 of the white light emitted by the white light emitting crystal grain 10 is always greater than 91 in different ambient temperatures (30℃~90℃), and the color rendering index R9 of the white light emitting crystal grain 10 is less significantly affected by the ambient temperature than that of the general white light emitting crystal grain.

Refer to Figure 9, which shows the color rendering index R12 changes of the white light emitting crystal grain 10 and general white light emitting crystal grains in different ambient temperatures. The color rendering index R12 change of the white light emitting crystal grain 10 is represented by the solid line in Figure 9, and the color rendering index R12 change of the general white light emitting crystal grain is represented by the dotted line in Figure 9. Figure 9 shows that the color rendering index R12 of the white light emitted by the white light emitting crystal grain 10 is always greater than 91 in different ambient temperatures (30℃~90℃).

Referring to FIG. 3, FIG. 4 and FIG. 10, the color coordinates corresponding to the light emitted by the white light emitting crystal grains 10 of the first white light group 11 after mixing in a CIE chromaticity diagram (in this embodiment, CIE 1976) as shown in FIG. 10 are defined as a first coordinate 112, the color coordinates corresponding to the light emitted by the white light emitting crystal grains 10 of the second white light group 12 after mixing in the CIE chromaticity diagram are defined as a second coordinate 122, and the color coordinates corresponding to the light emitted by the white light emitting crystal grains 10 of the third white light group 13 after mixing in the CIE chromaticity diagram are defined as a third coordinate 132. The color temperatures of the first coordinate 112, the second coordinate 122 and the third coordinate 132 are different from each other. In this embodiment, the first coordinate 112, the second coordinate 122 and the third coordinate 132 are not located on the black body radiation 41 for illustration, but in other embodiments, one of the first coordinate 112 and the third coordinate 132 may be located on the black body radiation 41, and the effect claimed in this case can still be achieved. The relevant color temperatures of the first white light group 11, the second white light group 12 and the third white light group 13 are respectively between 1800 and 2600K, 2600 and 4500K, and 6500 and 10000K. In this embodiment, the relevant color temperatures of the first white light group 11, the second white light group 12 and the third white light group 13 are respectively 1800K, 3500K and 10000K.

Among them, the triangular connection line of the first coordinate 112, the second coordinate 122 and the third coordinate 132 and the black body radiation 41 form two intersection points 18. The color temperature of one of the intersection points 18 is not higher than 1800K, and the color temperature of the other intersection point 18 is not lower than 10000K. In this embodiment, the intersection points 18 are located on the connection line of the first coordinate 112 and the third coordinate 132 for illustration, but the intersection points 18 can also be located on any two sides of the triangular connection line, and are not limited to this. The triangular connection line of the first coordinate 112, the second coordinate 122 and the third coordinate 132 surrounds and defines a dimming area 42, and the dimming area 42 includes part of the black body radiation 41. In other words, the black body radiation 41 in the dimming area 42 is the target of the predetermined dimming. Define the corresponding color coordinate of the light source after the light source unit 1 mixes light in the CIE chromaticity diagram as a mixed light coordinate 17.

The control unit 2 is, for example, a combination of a storage device such as a microprocessor, a memory, and a current driver, and can output driving currents to the first white light group 11, the second white light group 12, and the third white light group 13 according to an algorithm to control the brightness changes of the white light emitted by the first white light group 11, the second white light group 12, and the third white light group 13, so that the mixed light coordinate 17 moves in the dimming area 42 according to the brightness changes of the three, so as to mix the light to produce light sources with different related color temperatures from 1800K to 10000K. The algorithm is to calculate the power ratio of the first white light group 11, the second white light group 12 and the third white light group 13 corresponding to the predetermined color temperature (for example, 3000K) of the mixed light coordinate 17 in advance according to the spectra of the first white light group 11, the second white light group 12 and the third white light group 13 (for example, the first white light group 11 is 35%, the second white light group 12 is 63%, and the third white light group 13 is 3%), and fit its setting values into a function or a table, and then store the function or the table in the control unit 2 for use in the algorithm. The power ratio is, for example: when the light source unit 1 is expected to use 300W of power, then according to the above power ratio, 300W of power is allocated to the first white light group 11, the second white light group 12 and the third white light group 13 for light emission.

In this embodiment, in the algorithm, the power ratio of the mixed light coordinate 17 at each color temperature is set as shown in Table 2 below. It can be seen from Table 2 that the D _uv value (defined as the distance of the color coordinate from the black body radiation 41) measured by the mixed light coordinate 17 at each color temperature is within -0.0005 to 0.0005, and the CRI value (color rendering index) is also greater than 95. In other words, the mixed light coordinate 17 corresponding to the light source mixed by the present embodiment can fall on the black body radiation 41 or close to the black body radiation 41, and the light source has only a very slight difference from the real sunlight, and can achieve the effect of highly restoring the real color of the object.

Refer to FIG. 11 and FIG. 12 for another embodiment of the present embodiment. In another embodiment of the present embodiment, the light source unit 1 further includes a red light group 14, a green light group 15 and a blue light group 16 electrically connected to the control unit 2 and used to emit monochromatic light. The red light group 14 includes a plurality of red light emitting diode elements (not shown). The green light group 15 includes a plurality of green light emitting diode elements (not shown). The blue light group 16 includes a plurality of blue light emitting diode elements (not shown). The red light group 14, the green light group 15 and the blue light group 16 respectively receive currents of different sizes output by the control unit 2, so that the brightness of the monochromatic light emitted by the red light group 14, the green light group 15 and the blue light group 16 can be controlled and adjusted. The monochromatic light is defined as having a half-wave width range of 5nm~30nm.

The corresponding color coordinates of the red light group 14, the blue light group 16 and the green light group 15 in the CIE chromaticity diagram shown in FIG. 12 are defined as a red light coordinate 141, a green light coordinate 151 and a blue light coordinate 161 respectively. The connection line of the red light coordinate 141, the green light coordinate 151 and the blue light coordinate 161 surrounds and defines a light mixing area 43, and the range of the light mixing area 43 includes the dimming area 42 on the CIE chromaticity diagram and the area is larger than the dimming area 42.

In actual application, the control unit 2 first adjusts the power ratio of the first white light group 11, the second white light group 12 and the third white light group 13, so that the light source unit 1 provides a basic light source close to the black body radiation 41. Then, according to the needs, the power of the red light group 14, the green light group 15 and the blue light group 16 are adjusted to dye the basic light source. For example, when red light similar to sunlight is needed for photography, after adjusting the basic light source close to the black body radiation 41, the brightness of the red light group 14 can be adjusted according to the required saturation of red light. In this way, a light source with red light added to the basic light source can be provided.

In summary, the first LED element 102, the second LED element 103 and the third LED element 104 emit three kinds of blue light with wavelengths between 410nm and 450nm, between 450nm and 470nm and between 460nm and 490nm, so that the mixed light of the excited fluorescent layers 105 can appear as white light with blue-green light, so as to achieve the effect of simulating sunlight. In addition, the white light generated by the white light emitting crystal grains 10 has related color temperatures different from each other, and the white light generated by the white light emitting crystal grains 10 includes part of the black body radiation 41 in the dimming area 42 in the CIE chromaticity diagram. The control unit 2 is configured to output a current to control the brightness change of the white light generated by the white light emitting crystal grains 10 respectively, so that the mixed light coordinates 17 corresponding to the mixed light of the light source unit 1 can approach the black body radiation 41 as the brightness of the white light emitting crystal grains 10 changes, so as to achieve the effect that the light emitted by the lighting device is similar to sunlight at different color temperatures, and can achieve the effect of highly restoring the real color of the object. In addition, by setting the red light group 14, the green light group 15 and the blue light group 16, after adjusting the basic light source close to the black body radiation 41, the power of the red light group 14, the green light group 15 and the blue light group 16 can be adjusted according to the needs to dye the basic light source. In this way, the color saturation of the light source after mixing can be improved while taking into account good color rendering, so as to cope with the application of photography or various environments, so the purpose of this novel can be achieved.

However, the above is only an example of the implementation of this new model, and it cannot be used to limit the scope of the implementation of this new model. All simple equivalent changes and modifications made according to the scope of the patent application of this new model and the content of the patent specification are still within the scope of this new patent.

1: Light source unit

10: White light emitting crystals

101: Base plate

102: First light-emitting diode element

103: Second light-emitting diode element

104: The third light-emitting diode element

105: Fluorescent layer

11: The first white light group

112: First coordinate

12: Second white light group

122: Second coordinate

13: The third white light group

132: The third coordinate

14: Red light group

141: Red light coordinates

15: Green Light Group

151: Green light coordinates

16: Blu-ray Group

161: Blue light coordinates

17: Mixed light coordinates

18: Intersection

2: Control unit

3: Substrate

41: Blackbody radiation

42: Dimming area

43: Mixed light area

Other features and effects of the present invention will be clearly presented in the implementation method with reference to the drawings, wherein: FIG. 1 is a spectrum diagram illustrating the relative intensity variation of white light emitted by a general white light emitting crystal grain at different wavelengths; FIG. 2 is a CIE chromaticity diagram illustrating the color coordinates corresponding to two sets of luminous crystal grains of a general lighting device; FIG. 3 is a block diagram illustrating an implementation example of the present invention; FIG. 4 is a diagram illustrating the connection relationship between a plurality of white light emitting crystal grains and a base plate of the implementation example; and FIG. 5 is a diagram illustrating the connection relationship between a base plate, a first light emitting diode element, a second light emitting diode element, a third light emitting diode element, and three fluorescent layers of any white light emitting crystal grain. Relationship; Figure 6 is a spectrum diagram illustrating the relative intensity change of white light emitted by any white light emitting crystal grain at different wavelengths; Figure 7 is a diagram showing the relevant color temperature change of the white light emitting crystal grain and a general white light emitting crystal grain at different ambient temperatures; Figure 8 is a diagram showing the color rendering index R9 change of the white light emitting crystal grain and a general white light emitting crystal grain at different ambient temperatures; Figure 9 is a diagram showing the color rendering index R12 change of the white light emitting crystal grain and a general white light emitting crystal grain at different ambient temperatures; Figure 10 is a CIE chromaticity diagram of the embodiment; Figure 11 is a block diagram showing another embodiment of the embodiment; and Figure 12 is a CIE chromaticity diagram of another embodiment of the embodiment.

10: White light emitting crystals

101: Base plate

102: First light-emitting diode element

103: Second light-emitting diode element

104: The third light-emitting diode element

105: Fluorescent layer

Claims (15)

A white light emitting crystal chip, comprising: a base plate; a first light emitting diode element, disposed on the base plate, and capable of emitting a first blue light with a wavelength between 410nm and 450nm; a second light emitting diode element, disposed on the base plate, and capable of emitting a second blue light with a wavelength between 450nm and 470nm; a third light emitting diode element, disposed on the base plate, and capable of emitting a third blue light with a wavelength between 460nm and 490nm; and three fluorescent layers, respectively covering the surfaces of the first light emitting diode element, the second light emitting diode element, and the third light emitting diode element, When the fluorescent layers are irradiated by the first blue light, the second blue light and the third blue light respectively, the fluorescent layers will be excited to make the white light emitting crystal generate white light. The white light emitting chip as described in claim 1, wherein the color temperature of the first blue light emitted by the first light emitting diode element is between 2700K and 7500K, the color temperature of the second blue light emitted by the second light emitting diode element is between 2700K and 7500K, and the color temperature of the third blue light emitted by the third light emitting diode element is between 2700K and 7500K. The white light emitting crystal chip as described in claim 1, wherein the color rendering index R9 of the white light generated by the white light emitting crystal chip is greater than 91 when the ambient temperature is between 30°C and 90°C. The white light emitting crystal chip as described in claim 1, wherein the white light generated by the white light emitting crystal chip has a color rendering index R12 greater than 91 when the ambient temperature is between 30°C and 90°C. A lighting device, comprising: A light source unit, comprising at least three white light emitting crystals as described in any one of claims 1 to 4, the white light generated by the white light emitting crystals having color coordinates corresponding to a first coordinate, a second coordinate and a third coordinate in a CIE chromaticity diagram, respectively, the color temperatures of the first coordinate, the second coordinate and the third coordinate are different from each other, the line connecting the first coordinate, the second coordinate and the third coordinate forms two intersections with a black body radiation, the line connecting the first coordinate, the second coordinate and the third coordinate surrounds and defines a dimming area, wherein the dimming area includes part of the black body radiation, and the corresponding color coordinate of the light source after mixing of the light source unit in the CIE chromaticity diagram is defined as a mixed light coordinate; and A control unit is electrically connected to the light source unit to output current to the white light emitting chips to control their brightness changes respectively, so that the mixed light coordinate moves in the dimming area. A lighting device as described in claim 5, wherein at least two of the first coordinate, the second coordinate and the third coordinate are not located on the blackbody radiation. A lighting device as described in claim 5, wherein the first coordinate, the second coordinate and the third coordinate are not located on the blackbody radiation. A lighting device as described in claim 5, wherein a line connecting the first coordinate, the second coordinate and the third coordinate forms two intersection points with the black body radiation, wherein a color temperature of one of the intersection points is not higher than 1800K, and a color temperature of the other intersection point is not lower than 10000K. A lighting device as described in claim 5, wherein a line connecting the first coordinate and the third coordinate forms two intersection points with the black body radiation, wherein a color temperature of one intersection point is not higher than 1800K, and a color temperature of the other intersection point is not lower than 10000K. A lighting device as described in claim 5, wherein the associated color temperature of the first coordinate is between 1800 and 2600K. A lighting device as described in claim 10, wherein the associated color temperature of the second coordinate is between 2600 and 4500K. A lighting device as described in claim 11, wherein the associated color temperature of the third coordinate is between 6500 and 10000K. The lighting device as described in claim 5 further includes a substrate, and the white light emitting chips are arranged alternately on the substrate. A lighting device as described in claim 5, wherein the light source unit further includes a red light group, a green light group and a blue light group electrically connected to the control unit and used to emit monochromatic light, and the red light group, the green light group and the blue light group respectively receive the current output by the control unit to change their brightness. A lighting device as described in claim 14, wherein the corresponding color coordinates of the red light group, the green light group and the blue light group in the CIE chromaticity diagram are respectively defined as a red light coordinate, a green light coordinate and a blue light coordinate, and the line connecting the red light coordinate, the green light coordinate and the blue light coordinate surrounds a mixed light area, and the area of the mixed light area is larger than the area of the dimming area.