KR20120009527A - Multi color light emitting apparatus - Google Patents

Abstract

PURPOSE: A multicolor light emitting apparatus is provided to easily supply white light in a warm white range using a yellow LED chip in addition to red, green, and blue LED chips. CONSTITUTION: A package member(10) receives a plurality of LED chips in a sealed state. The multiple LED chips comprises a blue LED chip(31), a green LED chip(32), a red LED chip(33), and a yellow LED chip(34). The package member comprises a reflective housing(12) made of plastic or ceramic materials. The package member comprises a light transmissive encapsulating material(14) arranged within a cavity(124). A lead terminal is comprised of an input terminal(21) and an output terminal(22).

Description

Multicolor Light Emitting Device {MULTI COLOR LIGHT EMITTING APPARATUS}

The present invention relates to a multicolor light-emitting device using blue, green, red and yellow LED chips that are capable of emitting more light and, in particular, have a greater color temperature (CCT) control of white light.

As the information and communication industry develops, high performance of portable information processing devices and mobile communication terminals is continuously required, and high performance and high quality of various components of the system are continuously required. LCDs, which are commonly applied to monitors of medium and large terminals such as laptops, require a light source with a white backlight on the back. Cold cathode fluorescent lamps (CCFLs) have been widely used as such backlight sources. Cold cathode fluorescent lamps have advantages such as achieving uniform white light with high luminance, but may be used according to mercury regulations in the future. Difficulties are expected. Therefore, research on a backlight light source that can replace the CCFL is being actively conducted, and a backlight light source using a light emitting diode (Light Emitting Diode) has been spotlighted as a light source replacing a conventional cold cathode fluorescent lamp.

As described above, research into the direction of using a light emitting diode as a backlight light source of a display device such as an LCD has been mainly developed, and research into other uses such as general lighting, automotive lighting, and LED dot mattresses is relatively small. come. In order to broaden the application range of the light emitting diode, many characteristics or performances such as color rendering, color reproducibility, compatibility, or color control are required to suit the application.

Conventional light emitting diodes or light emitting devices using the same realize white light through a combination of red, green, and blue R, G, and B light sources, and this method has limitations in improving color rendering and color reproducibility of white light. FIG. 1 shows the full color of a conventional white light emitting device on a CIE1931 chromaticity coordinate diagram. Referring to FIG. 1, a triangle representing the three primary color coordinates used by the NTSC standard is indicated, and R, The light in the white region may be implemented according to the change in the slope of the coordinate due to the current applied to the G and B light emitting diodes. At this time, the white region appears along a black body locus curve (BBL curve), and the inclination of the black body locus increases from ∞ to about 4000K based on the horizontal axis and the vertical axis xy, but passes about 4000K. It is decreasing. For that reason, there is a region that cannot be realized even by adjusting the brightness of R, G, and B light emitting diodes according to current. This is why conventional light emitting devices using light emitting diodes do not realize white light of all white regions (particularly, warm white regions) of the blackbody trajectory. In addition, since only conventional R, G, and B light emitting diodes are used, since the number of colors that can be obtained by the combination of R, G, and B light emitting diodes is limited to seven, there are limitations in producing various colors of illumination. .

The technical problem of the present invention is that by adjusting the brightness of the blue, green, red and yellow LED chips located in one package member individually or in unit groups, various colors can be produced, and in particular, all white regions of the blackbody trajectory. It is to provide a versatile multicolor light emitting device capable of realizing white light.

According to one aspect of the invention, at least a portion of the package member having a light transmitting; Lead terminals provided on the package member and configured of input terminals and output terminals; Blue, red, green, and yellow LED chips housed in the package member and configured to emit light by receiving power from the lead terminals; There is provided a multicolor light emitting device including control means for controlling the current flowing through the lead terminals to adjust the brightness of the blue, red, green, and yellow LED chips individually or in unit groups.

According to an embodiment of the present invention, the input terminals may include a first input terminal connected to an input side of the blue LED chip and the green LED chip, and a second voltage different from the first voltage for power input of a first voltage. For power, it is preferred to include a second input connected to the input side of the red LED chip and the yellow LED chip.

Preferably, in the package member, the first input terminal is located between an output terminal connected to the blue LED chip and an output terminal connected to the green LED chip, and the second input terminal is an output terminal connected to the red LED chip and the yellow LED. It is desirable to be located between the outputs connected to the chip. In addition, the first voltage is a forward voltage (Vf) of 3.2V, the second voltage is preferably a forward voltage (Vf) of 2.1V. In this case, the LED chips may be mounted on the lead terminal as the output terminal or the lead terminal as the input terminal, depending on the position of the (+) (-) electrode, and the LED chips may be mounted in any package member other than the lead terminal. Each of the (+) and (-) electrodes may be connected to each of the input and output terminals while being mounted at the portion of.

According to another embodiment of the present invention, the input terminals may include first, second, third, and fourth input terminals connected to input sides of the blue, green, red, and yellow LED chips, and the blue, green, red, The yellow LED chips may include first, second, third, and fourth output terminals respectively connected to the output side of the yellow LED chips.

Preferably, in the package member, each of the first, second, third and fourth input terminals is disposed to face each of the first, second, third and fourth output terminals. Device.

In the present invention, the package member, the housing having a cavity for accommodating the LED chips on the upper surface, the end portion of the lead terminal is extended and positioned near the lower surface, the front end of the LED chip and the lead terminal It is preferable to include a translucent encapsulant formed in the cavity to cover the field and the bonding wire. The apparatus may further include storage means for storing light ratios between the blue, green, red, and yellow LED chips, wherein the control means may adjust a current flowing through the lead terminals according to data stored in the storage means. Moreover, it is preferable that a yellow LED chip has a peak of a light emission wavelength in 580-600 nm. Including the orange wavelength of 580 ~ 600nm, the term 'yellow' in the present specification is defined as a broad yellow including 'orange'.

According to the present invention, by using a yellow LED chip in addition to the red, green, and blue LED chips, a blackbody trajectory including an area not obtained by a combination of existing red, green, and blue (R, G, B) light sources. It is possible to implement light in all white areas, and in particular, it is easy to implement white light in warm white areas, which has been required for many lighting applications. In addition, the present invention, it is possible to implement a yellow wavelength that was difficult to implement in the full color of the existing combination of R, G, B light source, thereby increasing the color gamut (or color reproduction area), In this case, there is an effect of increasing the number from the existing R, G, B light source from seven to 15. In addition, the luminous intensity of the green LED chip is relatively compensated by the addition of the yellow LED chip, thereby increasing the luminous intensity of the blue LED chip, and thus, the overall luminous intensity of the white light may also be higher.

1 is a CIE1931 chromaticity coordinate diagram showing the full color of a conventional white light emitting device.
Figure 2 is a plan view showing an LED package which is part of a multicolor light emitting device according to an embodiment of the present invention.
3 is a cross-sectional view of the LED package shown in FIG.
4 is a circuit diagram illustrating a white light emitting device according to an embodiment of the present invention.
FIG. 5 is a circuit diagram illustrating a white light emitting device according to another embodiment of the present invention. FIG.
FIG. 6 is a plan view illustrating an LED package of the white light emitting device of FIG. 5. FIG.
7 shows the spectral distribution of white light obtained by the combination of blue, green, red and green LED chips according to the present invention.
8 is a CIE 1931 chromaticity diagram illustrating the full color coordinates of a multicolor light emitting device according to the present invention obtained by using blue, green, red and yellow LED chips.
FIG. 9 is a chromaticity diagram showing color coordinates for bluish white light (BLUISH), white light of color temperature 7400K, 4000K, 2800K, 2000K that can be obtained through adjustment of the brightness ratio of blue, green, red and yellow LED chips.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples to ensure that the spirit of the present invention can be fully conveyed to those skilled in the art. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. And, in the drawings, the width, length, thickness, etc. of the components may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

FIG. 2 is a plan view showing an LED package which is a part of a multicolor light emitting device according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view of the LED package shown in FIG. FIG. 4 is a circuit diagram for describing a white light emitting device according to an embodiment of the present invention.

2 and 3, the LED package according to the present embodiment includes a package member 10, lead terminals 21 and 22, and a plurality of LED chips 31, 32, 33, and 34. do. At this time, the lead terminals are composed of input terminals 21 and output terminals 22, and the plurality of LED chips are a blue LED chip 31, a green LED chip 32, a red LED chip 33 and a yellow LED chip ( 34).

The package member 10 accommodates the LED chips 31, 32, 33, and 34 in a sealed state, and includes a reflective housing 12 made of a plastic or ceramic material having a cavity 124 formed on an upper surface thereof. do. In addition, the package member 10 includes a light-transmissive encapsulant 14 (indicated by a dot hatch) filled and formed in the cavity 124. The encapsulant 14 permits light emission from the LED chips 31, 32, 33, and 34, while the LED chips 31, 32, 33, and 34 exist in the cavity 124. The tip ends of the lead terminals 21 and 22 and the bonding wires W are covered to protect from the outside. A part of the package member 10 according to the present exemplary embodiment, that is, only the portion of the encapsulant 14 except the housing has light transmitting properties, but the package member 10 may have a light transmitting property as a whole, and a package member having overall light transmitting property ( As a LED package including 10), a lamp type LED package is well known.

As the material of the encapsulant 14, a resin such as transparent silicone or transparent epoxy may be used. As shown in FIG. 3, the lead terminals 21 and 22 connected to electrodes on a printed circuit board (not shown) may be provided on the outer bottom surface of the package member 10. Only 21 are shown). Accordingly, the package member 10 has a structure in which the direction in which the light is emitted and the direction in which the light is emitted are opposite to each other.

As shown in FIG. 2, the lead terminals 21 and 22 have two input terminals, that is, the first and second input terminals 21a and 21b, and four output terminals, that is, the first and second terminals. And third and fourth input terminals 22a, 22b, 22c, and 22d. In this case, the blue LED chip 31 is mounted on the top surface of the first output terminal 22a and the green LED chip 32 is mounted on the top surface of the second output terminal 22b in the package member 10. In addition, a red LED chip 33 is mounted on the upper surface of the third output terminal 22c and a yellow LED chip 34 is mounted on the upper surface of the fourth output terminal 22d. The first input terminal 21a is electrically connected to each of the blue and green LED chips 31 and 32 by bonding wires W, and the second input terminal 21b is connected to the bonding wires w. By the red and yellow LED chips 33 and 34, respectively. Also, in an optimal arrangement, the first input terminal 21a is located between the first output terminal 22a and the second output terminal 22b, and the second input terminal 21b is the third output terminal 22c and the fourth output terminal. It is located between 22d.

However, the LED chips are not necessarily mounted in the arrangement as shown in FIG. 2, and the LED chips may be mounted to facilitate the implementation of the electric circuit to be described with reference to FIG. 4.

2 and 4 together, the first input terminal 21a is connected to the input side of the blue LED chip 31 and the input side of the green LED chip 32, and the second input terminal 21b. Is connected to the input side of the red LED chip 33 and the input side of the yellow LED chip 34. In addition, each of the blue, green, red, and yellow LED chips 31, 32, 33, and 34 is connected to each of the first, second, third, and fourth output terminals 22a, 22b, 22c, and 22d at the output side. do.

 According to an embodiment of the present invention, forward voltage power of 3.2V is applied to the blue LED chip 31 and the green LED chip 32 from the first input terminal 21a, and the red LED chip 33 The yellow LED chip 34 receives a forward voltage of 2.1V from the second input terminal 21b. As such, the pairing of the blue and green LED chips 31 and 32 and the red and yellow LED chips 33 and 34 according to the voltage is performed by the blue LED chip 31 and the green LED chip 32. This is because the voltage characteristics of are similar to each other, and the voltage characteristics of the yellow LED chip 34 and the red LED chip 33 are similar. When LED chips having significantly different voltage characteristics are connected to input terminals of the same voltage, current flows in one direction, making it difficult to obtain desired luminance.

FIG. 7 is a view showing a spectral distribution of white light obtained by a combination of blue, green, red and green LED chips. Referring to FIG. 7, four LED chips 31, 32, 33, and 34; FIGS. 2 and FIG. It can be seen that the four peaks are present in the wavelength region of blue, green, red and yellow, respectively, by the light emitted from the reference 4). In the embodiment of the present invention, the blue LED chip 31 has a peak of blue emission wavelength in the 420 ~ 470nm region, the green LED chip 32 has a peak of the green emission wavelength in the 500 ~ 550nm region, red LED Chip 33 has a peak of a red light emission wavelength in the region 610 ~ 660nm, yellow LED chip 34 has a peak of the light emission wavelength in 580 ~ 600nm.

 As described above, in the case of using the LED chips 31, 32, 33, and 34 which emit light in the blue, green, red, and yellow wavelength ranges, the color rendering area (range) is greatly expanded, and the color rendering and color reproducibility of the white light are increased. You can increase it. The full color of the multi-color light emitting device according to the present invention is 116.4% when the color gamut is 100% of the NTSC standard, which is 109.4% when using R, G, and B light sources. This is an increase of 7%. FIG. 8 is a CIE 1931 chromaticity coordinate diagram showing full color coordinates obtained by using a blue, green, red and yellow LED chip in a multicolor light emitting device according to the present invention, and compared with FIG. 1 according to the prior art. Referring to FIG. 8, it is shown that the area of the color coordinate is expanded by the adoption of the yellow LED chip at the point indicated by the arrow.

The above expansion contributes to increasing the aforementioned color reproducibility to 116.4%, and makes it possible to realize, for example, warm white white light, which was difficult to implement by conventional R, G and B light sources. When only the R, G, and B light sources are used, the color temperature range of the white light is limited to ∞ to 4000K along the blackbody locus, whereas in accordance with the present invention, when using blue, green, red, and yellow LED chips, ∞ along the blackbody locus White light of a color temperature range of from 4000K to 1000K can be realized.

On the other hand, the light emitting device according to the present invention, not only can provide a white light by adjusting the color temperature range widely, but also the number of combinations of the LED chips 31, 32, 33, 34 also use R, G, B light source It can be magnified from seven to fifteen times, to provide light of various colors that can be obtained by the combination. The combination of light according to the invention is R (red), G (green), B (blue), Y (yellow), RG, RB, RY, GB, GY, BY, RGB, RGY, RBY, GBY, RGBY.

Referring back to FIG. 4, the multi-color light emitting device 1 according to the present embodiment includes control means for controlling the brightness or the blinking of the LED chips 31, 32, 33, and 34 individually or in unit groups together with the LED package. (30). The control means 30 controls the current flowing through the lead terminals electrically connected to the blue, red, green, and yellow LED chips 31, 32, 33, and 34, thereby controlling the blue, red, green, and yellow LED chips. Adjust the brightness individually or in groups of units. At this time, for example, an element whose resistance is changed by the control means 30 may be used for current regulation. In addition, the multicolor light emitting device 1 further comprises a storage means 40 for storing the light ratios between the blue, green, red and yellow LED chips 31, 32, 33, 34. On the basis of the data of several predetermined light intensity ratios stored in the storage means 40, the control means 30 is a current flowing through the lead terminals 21 or 22 and the LED chip 31, 32, 33, 34. And accordingly, the brightness of the LED chips 31, 32, 33, 34 can be adjusted.

5 and 6 are views for explaining a multi-color light emitting device according to another embodiment of the present invention.

5 and 6, the multi-color light emitting device 1 according to the present embodiment also, like the previous embodiment, together with the LED package, blue, green, red, yellow LED chip 31, 32 of the LED package And control means 30 for controlling the brightness or flashing of the light emitting diodes 33 and 34, and, in combination with the LED chips, storing means 40 for storing data having a predetermined light intensity ratio in order to obtain a color temperature of a desired white light. ).

Also in this embodiment, the lead terminals provided on the package member 10 include an input terminal 21 and an output terminal 22, but different from the previous embodiment, the input terminals 21 are the blue, green, red, and yellow LEDs. The first, second, third, and fourth input terminals 21a, 21b, 21c, and 21d connected to the input sides of the chips 31, 32, 33, and 34, respectively.

In this case, first, second, third, and fourth output terminals 22a, 22b, 22c, and 22d are connected to the output sides of the blue, green, red, and yellow LED chips 31, 32, 33, and 34, respectively. do. As shown in FIG. 6, in the package member 10, each of the first, second, third, and fourth input terminals 21a, 21b, 21c, and 21d may be the first, second, or third. The third and fourth output terminals 22a, 22b, 22c, and 22d are disposed to face each other. This arrangement is useful to prevent the bonding wires W disposed between the input terminals 21 and the output terminals 22 from interfering with each other.

As described in detail above, according to the present invention, the multi-color light emitting device 1 is wider than the conventional one through the light ratio adjustment of the blue, green, red, and yellow LED chips 31, 32, 33, and 34. White light in a color temperature range can be realized. Such adjustment of the brightness ratio is performed by the control means 30 (see FIGS. 4 and 5) of the multicolor light emitting device 1. In addition, the light intensity ratio is previously stored in the storage means 30 (see FIGS. 4 and 5) of the multicolor light emitting device 1. [Table 1] below shows the light intensity ratios obtained by adjusting the current of the blue, green, red, and yellow LED chips 31, 32, 33, and 34 so as to obtain various white lights, and FIG. 9 shows [Table 1]. Color coordinates for bluish white light (BLUISH), color temperature 7400K, 4000K, 2800K, 2000K that can be obtained by adjusting the brightness ratio of the blue, green, red, and yellow LED chips 31, 32, 33, and 34 indicated in A chromaticity diagram showing

At this time, the white light of the 4000K, 2800K, and 2000K color temperatures in Table 1 and FIG. 9 is white light that can be obtained when using the blue, green, red, and yellow LED chips according to the present invention.

Claims (23)

housing;
Lead terminals disposed on the housing and composed of input terminals and output terminals; And
At least four LED chips mounted on the lead terminals and emitting different colors;
The at least four LED chips are multi-colored light emitting device, characterized in that the brightness is controlled by individual or unit groups, symmetrically arranged with respect to the center of the housing. The method according to claim 1,
Wherein the at least four LED chips comprise a blue LED chip, a red LED chip, a green LED chip, and an LED chip having a different color from the blue, red, and green LED chips. The method according to claim 2,
And a blue light, a green light, a red light, and a white light, respectively, by the combination of the at least four LED chips. The method according to claim 2,
And one of the red LED chip and the green LED chip is disposed in a diagonal direction of the LED chip having the different color. The method of claim 4,
And the blue LED chip is disposed in a diagonal direction of the LED chip having the different color. The method according to claim 2,
And the blue LED chip and the green LED chip are disposed adjacent to each other. The method of claim 6,
The red LED chip and the LED chip having a different color are arranged adjacent to each other. The method according to claim 2,
The LED chip having a different color emits a color that complements the brightness of the green LED chip. The method according to claim 8,
The LED chip having a different color is a multi-color light emitting device, characterized in that the yellow LED chip. The method according to claim 1,
The housing is a multi-color light-emitting device characterized in that the plastic or ceramic material. The method according to claim 10,
And a sealing material covering the at least four LED chips. The method according to claim 1,
The output terminal includes a surface on which the LED chip is mounted, wherein the surface on which the LED chip is mounted has a wider width than the other surface. The method according to claim 1,
The input terminal is connected to each of the LED chips, or a multi-color light emitting device, characterized in that commonly connected to some of the at least four LED chips. The method according to claim 1,
And a control means for individually controlling the brightness or the blinking of the at least four LED chips. The method according to claim 1,
And the housing comprises a cavity. housing;
Lead terminals disposed on the housing and composed of input terminals and output terminals; And
At least four LED chips mounted on the lead terminals and emitting different colors;
Wherein the at least four LED chips are controlled in intensity by an individual or unit group and selectively emit blue light, green light, red light, and white light. The method according to claim 16,
Wherein the at least four LED chips comprise a blue LED chip, a red LED chip, a green LED chip, and an LED chip having a different color from the blue, red, and green LED chips. 18. The method of claim 17,
And one of the red LED chip and the green LED chip is disposed in a diagonal direction of the LED chip having the different color. 18. The method of claim 17,
And the blue LED chip, the red LED chip, the green LED chip, and the LED chip having the different colors are arranged adjacent to each other. 18. The method of claim 17,
The LED chip having a different color emits a color that complements the brightness of the green LED chip. The method of claim 20,
The LED chip having a different color is a multi-color light emitting device, characterized in that the yellow LED chip. The method according to claim 16,
And a sealing material covering the at least four LED chips. The method according to claim 16,
And a control means for individually controlling the brightness or the blinking of the at least four LED chips.

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