CN101075608A - Light emitting device and method of operation thereof - Google Patents

Abstract

The present invention provides a light-emitting device, which includes a first light-emitting device for emitting a first emission light having a first wavelength range, a second light-emitting device for emitting a second emission light having a second wavelength range, a third light-emitting device for emitting a third emission light having a third wavelength range, and a fourth light-emitting device for emitting a fourth emission light having a fourth wavelength range; wherein the first, second, third, and fourth wavelength ranges are different from each other and together cover the spectrum of visible light.

Description

Light emitting device and method of operation thereof

technical field

The present invention relates to a light-emitting device, in particular to a four-color light-emitting device capable of emitting white light and a method for operating the four-color light-emitting device.

Background technique

Light emitting diodes (LEDs), commonly used as light sources, illuminators, indicator lights, and displays, are well-known solid-state light-generating devices that generate light with a peak wavelength in a specific region of the spectrum. LEDs are advantageous for use as light sources for several reasons. LEDs are more mechanically robust when compared to light bulbs or fluorescent lamps (fluorescent lamps) because they can generally withstand greater shock or vibration. In addition, LEDs generally have a long life, reducing the frequency of replacing damaged diodes. When it is necessary to replace an LED, it is also easier and more economical than replacing a fluorescent source. In addition, LEDs have the advantages of low power consumption, small size and light weight, so they can be used in a variety of display applications, from backlighting for liquid crystal displays to traffic lights.

Currently developed LEDs can emit red (R), green (G), and blue (B) color light respectively. Since white is very important for full-color image display, there are at least two different methods to emit white light in the prior art. In the first method, the light emitted by each of the red, green, and blue LEDs is mixed to provide white emission, or other color emission if necessary. However, in the first red-green-blue-based approach, it may be difficult to provide amber (yellow) emission in the wavelength range of about 570nm (nanometer) to 600nm. In addition, the first approach may also be difficult to provide white emission with a correlated color temperature (CCT) below about 3000°K (Kirvin's absolute temperature).

In the second approach, a wavelength conversion technique is used to achieve the emitted light color. The wavelength conversion technology is mainly based on the principle that phosphor placed on a light-emitting component absorbs light emitted from the light-emitting component and emits light with a wavelength different from that of the absorbed light. In particular, after the phosphor absorbs the light emitted by the light-emitting component, it emits photo-luminescence with different emission colors. For example, in LEDs based on wavelength conversion technology, the blue light emitted from the blue light-emitting component is partially or completely affected by phosphor to undergo wavelength conversion. As a result, light of a color different from blue light is radiated. For example, when using yellow phosphorous, the wavelength-converted yellow light can be mixed with unconverted blue light to provide a mixed light. In theory, this mixed light appears white when viewed from the outside of the LED. The disadvantage of the second method is that, due to the relatively small thickness of the phosphor layer, the amount of light absorbed by the phosphor layer is also small. Therefore, the amount of emitted yellow light does not reach a satisfactory level. For this reason, the emitted color perceived by the viewer is not the expected color, ie not white, but may be bluish or yellowish white (bluish white or yellowish white).

Therefore, it would be desirable to have a lighting device that can provide emitted light of a desired color, such as white light, and a method of operating such a lighting device to provide better color rendering.

Contents of the invention

The present invention relates to a light emitting device and a method of operating the light emitting device to overcome one or more problems caused by limitations and disadvantages in the prior art.

According to an embodiment of the present invention, a light emitting device capable of emitting white light or light of other colors is provided. The device includes a first light-emitting device for emitting first emission light with a first wavelength range, a second light-emitting device for emitting second emission light with a second wavelength range, and a third light-emitting device for emitting light with a second wavelength range The third emission light in the third wavelength range, and a fourth light-emitting device for emitting fourth emission light in the fourth wavelength range; wherein the first, second, third, and fourth wavelength ranges are different from each other, and together cover the spectrum of visible light.

Also according to the present invention, there is provided a light emitting device capable of emitting white light or light of other colors. This device comprises a first light-emitting device for emitting red light, a second light-emitting device for emitting green light, a third light-emitting device for emitting blue light, and a fourth light-emitting device for emitting amber light; wherein, by Emission of white light is provided by combining the first, second, third, and fourth light emitting devices.

Further according to the present invention, there is provided a light emitting device capable of emitting white light or light of other colors. The device includes a plurality of first light-emitting devices for emitting first emission light with a first wavelength range, a plurality of second light-emitting devices for emitting second emission light with a second wavelength range, and a plurality of third light-emitting devices for emitting light with a second wavelength range. The third emission light in the third wavelength range, and the plurality of fourth light-emitting devices are used to emit the fourth emission light with the fourth wavelength range; wherein, the plurality of first, second, third, and fourth light-emitting devices are based on The rows and columns are arranged in a matrix, and the first, second, third, and fourth wavelength ranges are different from each other, and together cover the spectrum of visible light.

Also according to the present invention, there is provided a method for operating a light emitting device emitting white light or light of another color. The method comprises: emitting first emission light having a first wavelength range from a first light emitting device of the light emitting device, emitting second emission light having a second wavelength range from a second light emitting device of the light emitting device, and emitting from a second light emitting device of the light emitting device The third light-emitting device emits the third emission light with the third wavelength range, and the fourth emission light with the fourth wavelength range is emitted from the fourth light-emitting device of the light-emitting device; mixing the light from the first, second, third, and the light emitted by the fourth light emitting device to generate white emission light.

Also in accordance with the present invention, there is provided a method for operating a lighting device capable of emitting white or other colored light. The method includes: emitting red emission light from a first light emitting device of the light emitting device, emitting green emission light from a second light emitting device of the light emitting device, emitting blue emission light from a third light emitting device of the light emitting device, and emitting light from the light emitting device A fourth light emitting device of the device emits amber emission light; and mixes the light emitted from the first, second, third, and fourth light emitting devices to produce white emission light.

The foregoing summary of the invention and the following detailed description of the embodiments can be better understood by referring to the accompanying drawings. In order to illustrate the invention, the drawings show presently preferred embodiments of the invention. However, the invention is not limited to the means and instrumentalities shown in the figures.

Description of drawings

FIG. 1A is a schematic diagram of a light emitting device according to an embodiment of the present invention;

Fig. 1B is a top view of the light emitting device shown in Fig. 1A;

2A, 2B and 2C are schematic diagrams of a light emitting device according to another embodiment of the present invention;

Fig. 3A is a chromaticity coordinate system, defines the color in the color space;

Figure 3B is a Planck plot obtained from the chromaticity coordinate system shown in Figure 3A; and

FIG. 4 is a flowchart showing a method for operating a light emitting device according to an embodiment of the present invention.

[Description of main component symbols]

10 light emitting device

R The first light-emitting device (emitting red light)

G The second light-emitting device (emitting green light)

B The third light-emitting device (emitting blue light)

A The fourth light-emitting device (emitting amber light)

12 First base

12-R pin

12-G pin

12-B pin

12-A pin

14 base

15 gold wire

16 second base

17 pins

18 Transparent polymer or plastic molding compound

Detailed ways

FIG. 1A is a schematic diagram of a light emitting device 10 according to an embodiment of the present invention. Please refer to Fig. 1A, the light-emitting device 10 includes a first light-emitting device, labeled R, for providing first light emission, a second light-emitting device, labeled G, for providing second light emission, a third light-emitting device , marked as B, for providing the third emitted light, and a fourth light emitting device, marked as A, used for providing the fourth emitted light. The wavelength ranges of the first, second, third, and fourth emitted lights are different from each other, but together cover the spectrum of visible light. The visible light spectrum includes a range of wavelengths falling between approximately 380nm (nanometers) and 780nm, which ranges from violet through blue, green, yellow, orange, and red. Outside this range are ultraviolet rays with wavelengths less than 380nm and infrared rays with wavelengths greater than 780nm. According to an embodiment of the present invention, the first light-emitting device R is provided to emit red light in the wavelength range of 600nm to 640nm; the second light-emitting device G is provided to emit green light in the wavelength range of 500nm to 570nm; the third The light emitting device B is for emitting blue light with a wavelength range of 420nm to 500nm; the fourth light emitting device A is provided for emitting amber light with a wavelength range of 570nm to 600nm.

The light-emitting devices R, G, B, and A in this embodiment include most light-emitting diodes, but may include other light-emitting components, such as inorganic light-emitting components, laser diodes, inorganic thin-film electroluminescent sheets, and inorganic thin-film electroluminescent components . The first, second, third, and fourth light emitting devices R, G, B, and A are disposed on a first base 12 using, for example, an existing die bonding process. Pins 12-R, 12-G, 12-B, and 12-A extend from the first base 12 and penetrate a base 14, and function as a first electrode, for example, as a first and second electrode, respectively. , the cathodes of the third and fourth light emitting devices R, G, B, A. The first, second, third, and fourth light emitting devices R, G, B, A are each bonded to a second submount 16 via a gold wire 15 by wire bonding. The pin 17 extends from the second base 16 and penetrates the substrate 14, and its function is to serve as a second electrode, for example, as a common electrode for the first, second, third, and fourth light-emitting devices R, G, B, and A. anode. Pins 12-R, 12-G, 12-B, 12-A and 17 provide power to light emitting devices R, G, B, A. The luminous means R, G, B, A are completely encapsulated in a transparent polymer or plastic molding compound 18 , eg by conventional injection molding methods.

FIG. 1B shows a top view of the light emitting device 10 shown in FIG. 1A . FIG. 1A and FIG. 1B show a lamp-type light emitting device, which refers to a light emitting device including a plurality of pins penetrating a substrate. However, the present invention is not limited to lamp-type applications, but is equally applicable to chip-type light-emitting devices, that is, light-emitting devices comprising a plurality of pins mounted on a substrate surface.

2A, 2B and 2C are schematic diagrams of a light emitting device according to another embodiment of the present invention. Please refer to FIG. 2A , the light emitting device 21 includes a plurality of first, second, third, and fourth light emitting devices R, G, B, A, whose characteristics and functions have been discussed above with reference to FIGS. 1A and 1B. In the light emitting device 21, the light emitting devices R, G, B, A form a matrix of rows and columns. Each (horizontal) column of the matrix includes first, second, third and fourth light emitting devices R, G, B, A arranged in a periodic order. That is, for example the sequence R-G-B-A. According to another embodiment of the present invention, each (straight) row of the matrix comprises first, second, third and fourth light emitting devices R, G, B, A arranged in a periodic order.

Referring to FIG. 2B , the light emitting device 22 includes a plurality of first, second, third, and fourth light emitting devices R, G, B, and A forming a matrix of rows and columns. Each (horizontal) column of the matrix includes only one of the first, second, third, and fourth light-emitting devices R, G, B, and A. More specifically, the first light emitting device R is arranged in the first column, the second light emitting device G is arranged in the second column, and so on. Please refer to FIG. 2C , the light emitting device 23 includes a plurality of first, second, third, and fourth light emitting devices R, G, B, A forming a matrix of rows and columns. Each (horizontal) column of the matrix includes two of the first, second, third, and fourth light-emitting devices R, G, B, and A, and the other column directly adjacent to each column includes the first, third, and fourth light-emitting devices. Two, the third, and the fourth light-emitting devices R, G, B, and A are the other two. More specifically, when the second and fourth light emitting devices G and A are arranged in the first row, the first and third light emitting devices R and B are arranged in the second row, and so on.

FIG. 3A is a chromaticity coordinate system for defining colors in a color space. The purpose of providing FIG. 3A and FIG. 3B is to better understand the method for operating a light emitting device according to the present invention. In general, the color quality of emitted light can be measured using a number of different rating systems. "Chroma" is used to define the color hue (hue) and chroma (saturation). "CIE" is a chromaticity coordinate system developed by the International Commission on Illumination. Each CIE chromaticity coordinate is a definition of a color located in the "1931 CIE" color space. These coordinates are defined as x, y, z, and are respectively the ratio of the three standard primary colors X, Y, Z (tristimulus values) to the sum of the three tristimulus values. The CIE chart contains the distribution of the ratios x, y, z of the individual tristimulus values to their sum. When reducing the case where the coordinates x, y, z sum to 1, a two-dimensional CIE(x, y) diagram is usually used. Fig. 3A shows one of its examples. Please refer to FIG. 3A , green, blue, red, and white are roughly located in the upper area, the lower left area, the lower right area, and the central area of the CIE chart, respectively.

FIG. 3B is a Planckian Curve diagram obtained from the chromaticity coordinate system shown in FIG. 3A. White is an important factor for full-color image display in LED displays. Various white-like colors (white-like colors) can be described by a "correlated color temperature" (CCT). For example, when a metal is heated, light is emitted, and the light is initially red and flameless. As the metal heats up, the emitted light shifts to higher quantum energies, first reddish, then white, and finally bluish-white. A system has been developed to interpret the changes in these colors over a standard object called a blackbody radiator. Depending on the temperature, a blackbody source emits white-like rays. This white ray-like color can then be illustrated with a CIE chromaticity diagram. Therefore, for the light source to be identified, its correlated color temperature is the temperature at which the black body radiation source produces the chromaticity most similar to the chromaticity of the light source. Both color temperature and CCT are expressed in Kelvin's absolute temperature (°K). Please refer to FIG. 3B, and also refer to FIG. 3A to compare the coordinates. For LED applications, the required white emission CCT value falls at about 6500°K.

In addition, there is a "color rendering index" (color rendering index, CRI) established through visual experiments. Wherein, the correlated color temperature of an identified light source is determined first. Then use the light source to illuminate the eight standard color samples, and then use the light produced by the blackbody with the same color temperature to illuminate the eight standard color samples. If there is a standard color sample without discoloration, then the light source has a theoretically perfect special CRI value of 100. The common color rendering index is called "Ra", which is the average color rendering index of all eight standard color samples.

FIG. 4 is a flowchart showing a method for operating a light emitting device according to an embodiment of the present invention. Referring to FIG. 4 , in step 41 , a light emitting device having the first, second, third, and fourth light emitting devices as mentioned above is provided. Next, in steps 42, 43, 44, and 45, emit light from the first, second, third, and fourth light-emitting devices of the light-emitting device with the first, second, third, and fourth wavelengths respectively. The first, second, third, and fourth range emit light. In step 46, the emitted light from the first, second, third, and fourth light emitting devices is mixed to produce white emitted light. The first, second, third and fourth wavelength ranges are different from each other and together cover the spectrum of visible light. In one embodiment, the first, second, third, and fourth light emitting devices respectively emit red light, green light, blue light, and amber light.

Then in step 47, if necessary, adjust the emitted light intensity of one of the first, second, third, and fourth light-emitting devices, and change the white emitted light with the first correlated color temperature CCT value to the second CCT value . The correlated color temperature of the white emitted light generated in an embodiment of the present invention can be adjusted between approximately 1000°K to 10000°K, which produces a better color rendering index Ra than the prior art. In another embodiment, when adjusting the intensity of the emitted light, the first, second, and third emitted light are emitted with a predetermined light intensity ratio, and the intensity of the fourth emitted light is adjusted to obtain the Two CCT values of white emission light. In one embodiment, the intensity ratio of the red, green and blue emitted light is about 1:4.59:0.06. Then increase the intensity of the light emitted by amber, so that the CCT value changes towards the lower temperature in the Planck curve shown in Figure 3B; or decrease the intensity of the light emitted by amber, so that the CCT value changes towards the higher temperature in the Planck curve direction change.

In yet another embodiment, when adjusting the emitted light intensity, the first, second, and fourth emitted light intensities for generating white emitted light with the first CCT value remain unchanged, while the third emitted light intensity Then adjust to obtain white emission light with the second CCT value. For example, in one embodiment, the intensity of red, green, and amber emitted light remains unchanged, while the intensity of blue emitted light increases, so that the CCT value changes toward a higher temperature in the Planck curve; or the intensity of blue emitted light is reduced , so that the CCT value changes in the direction of lower temperature in the Planck curve.

The method of changing the CCT value of white emitted light is also applicable to emitted light of other colors than white in the visible light spectrum. According to an embodiment of the present invention, the first, second, and third emission lights are emitted with a predetermined light intensity ratio, and the intensity of the fourth emission light is adjusted to obtain a certain color emission in the visible light spectrum. Light. In another embodiment, one of the first, second, third and fourth light emitting devices is selected and emits light from the unselected light emitting device at a predetermined light intensity ratio. Then, the intensity of the emitted light emitted by the selected light-emitting device is adjusted to obtain emitted light of a certain color in the visible light spectrum.

In describing representative embodiments of the invention, the description may have presented the method or process of the invention as steps in a particular order. However, when such methods or procedures do not rely on the specific order of steps described herein, the methods or procedures of the present invention should not be limited to the specific order of steps described above. Those skilled in the art of such techniques will appreciate that other sequences of steps may also be applicable. Therefore, the specific sequence of steps described in this specification should not be construed as limiting the scope of claims. In addition, patent claims related to the method or procedure of the present invention should not be limited to the steps performed in the sequence described, and those skilled in the art can easily understand that such sequence can be changed and still remain within the spirit and scope of the present invention.

Various changes may be made in the above-described embodiments without departing from the broad concepts of the invention. Accordingly, the present invention is not limited to the particular embodiments disclosed, but covers various modifications and variations within the spirit and scope of the invention, as defined by the appended claims.

Claims (30)

1. A lighting device, characterized in that it comprises: A first light-emitting device is used to emit first light with a first wavelength range, a second light-emitting device is used to emit second light with a second wavelength range, and a third light-emitting device is used to emit light with a third The third emission light in the wavelength range, and a fourth light-emitting device is used to emit the fourth emission light with the fourth wavelength range; wherein, the first, second, third, and fourth wavelength ranges are different from each other and share the same Covers the spectrum of visible light. 2. The light emitting device according to claim 1, wherein the first wavelength range extends from 600nm to 640nm. 3. The light emitting device according to claim 1, wherein the second wavelength range extends from 500nm to 570nm. 4. The light emitting device according to claim 1, wherein the third wavelength range extends from 420nm to 500nm. 5. The light emitting device according to claim 1, wherein the fourth wavelength range extends from 570nm to 600nm. 6. A lighting device, characterized in that it comprises: a first light emitting device for emitting red light; a second light emitting device for emitting green light; a third light emitting device for emitting blue light; and a fourth light emitting device for emitting amber light; Wherein, white emission light is provided by combining the first, second, third, and fourth light emitting devices. 7. The light emitting device according to claim 6, wherein the light emitted by the first light emitting device has a wavelength range extending from 600nm to 640nm. 8. The light emitting device according to claim 6, wherein the light emitted by the second light emitting device has a wavelength range extending from 500nm to 570nm. 9. The light emitting device according to claim 6, wherein the light emitted by the third light emitting device has a wavelength range extending from 420nm to 500nm. 10. The light emitting device according to claim 6, wherein the light emitted by the fourth light emitting device has a wavelength range extending from 570nm to 600nm. 11. A light emitting device, characterized in that it comprises: The plurality of first light emitting devices are used to emit first emitted light having a first wavelength range; a plurality of second light emitting devices for emitting second emission light having a second wavelength range; a plurality of third light emitting devices for emitting third emission light having a third wavelength range; and The plurality of fourth light emitting devices are used to emit fourth emission light having a fourth wavelength range; Wherein, the plurality of first, second, third, and fourth light-emitting devices are arranged in a row-column matrix, and the first, second, third, and fourth wavelength ranges are different from each other, and together cover the spectrum of visible light . 12 . The light emitting device according to claim 11 , wherein each row of the matrix includes the first, second, third and fourth light emitting devices arranged in a periodic order. 13 . 13. The light emitting device according to claim 11, wherein each straight row of the matrix includes the first, second, third and fourth light emitting devices arranged in a periodic order. 14. The light emitting device according to claim 11, wherein each column of the matrix includes only one of the first, second, third and fourth light emitting devices. 15. The light-emitting device according to claim 11, wherein each row of the matrix includes two kinds of the first, second, third, and fourth light-emitting devices, and each column Another column directly adjacent includes the other two of the first, second, third, and fourth light-emitting devices. 16. A method for operating a light emitting device, comprising the following steps: emitting first emitted light having a first wavelength range from a first light emitting device of the light emitting device; emitting second emitted light having a second wavelength range from a second light emitting device of the light emitting arrangement; emitting third emitted light having a third wavelength range from a third light emitting device of the light emitting arrangement; emitting fourth emitted light having a fourth wavelength range from a fourth light emitting device of the light emitting arrangement; Light emitted from the first, second, third, and fourth light emitting devices is mixed to produce white emitted light. 17. The operating method of a light emitting device as claimed in claim 16, wherein the first, second, third and fourth wavelength ranges are different from each other and together cover a spectrum of visible light. 18. The method of operating a light emitting device according to claim 16, further comprising generating white emission light with a correlated color temperature ranging from 1000°K to 10000°K. 19. The method for operating a light emitting device according to claim 16, further comprising: emitting the first, second, and third emitted light with a predetermined light intensity ratio; and The intensity of the fourth emitted light is adjusted to obtain white emitted light with a predetermined correlated color temperature. 20. The operating method of the light emitting device according to claim 16, further comprising: emitting the first, second, and third emitted light at a predetermined light intensity ratio; and The intensity of the fourth emitted light is adjusted to obtain emitted light of a certain color in the visible light spectrum. 21. A method for operating a light emitting device, comprising the following steps: emitting red emission light from the first light emitting device of the light emitting device; emitting green emission light from a second light emitting device of the light emitting device; emitting blue emission light from a third light emitting device of the light emitting device; emitting amber emission light from a fourth light emitting device of the light emitting device; and Light emitted from the first, second, third, and fourth light emitting devices is mixed to produce white emitted light. 22. The method for operating a light emitting device according to claim 21, further comprising emitting red emission light with a wavelength ranging from 600nm to 640nm. 23. The method for operating a light emitting device according to claim 21, further comprising emitting green emission light with a wavelength ranging from 500 nm to 570 nm. 24. The operating method of the light emitting device according to claim 21, further comprising emitting blue emission light with a wavelength range of 420nm to 500nm. 25. The operating method of the light emitting device according to claim 21, further comprising emitting amber emission light in a wavelength range of 570nm to 600nm. 26. The operating method of the light emitting device according to claim 21, further comprising: emitting the red, green and blue light at a predetermined intensity ratio; and The intensity of the amber emission is adjusted to obtain a white emission having a predetermined correlated color temperature. 27. The operating method of the light emitting device according to claim 21, further comprising: Selecting one of the first, second, third and fourth light-emitting devices; emitting light from unselected light emitting devices at a predetermined intensity ratio; and The intensity of the emitted light emitted by the selected light emitting device is adjusted to obtain white emitted light with a predetermined correlated color temperature. 28. The operating method of the light emitting device according to claim 21, further comprising: Selecting one of the first, second, third and fourth light-emitting devices; emitting light from unselected light emitting devices at a predetermined intensity ratio; and The intensity of the emitted light emitted by the selected light-emitting device is adjusted to obtain emitted light with a certain color in the visible light spectrum. 29. The operating method of the light emitting device as claimed in claim 27, further comprising increasing the intensity of the amber emitted light to obtain white emitted light at a lower correlated color temperature. 30. The method for operating a light emitting device as claimed in claim 27, further comprising increasing the intensity of the blue emitted light to obtain white emitted light at a higher correlated color temperature.

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