KR100855556B1 - Light emitting diode - Google Patents

Abstract

An object of the present invention is to combine all the advantages of the light emitting diode using the three-color light emitting chip and the light emitting diode using the phosphor excitation can express all the colors of the area required in NTSC, high luminous efficiency and consistent color reproduction and consumption The present invention provides a light emitting diode capable of lowering power.

To this end, the present invention is a mixture of a lead frame, at least one light emitting chip of two kinds of colors die-bonded to the lead frame of red, green, blue light emitting chips, phosphors emitted in colors other than the two types of die bonding. To provide a light emitting diode comprising a resin encapsulating agent for sealing the light emitting chip.

Light Emitting Diode, Light Emitting Chip, Wavelength, Phosphor, Resin Encapsulant

Description

Light Emitting Diodes

1 is a plan view of a light emitting diode according to a first embodiment of the present invention.

2 is a side cross-sectional view of a light emitting diode according to a first embodiment of the present invention.

3 is a perspective view showing a light emitting diode according to a second embodiment of the present invention.

4 is a graph showing excitation wavelength characteristics of a light emitting diode according to a first embodiment of the present invention.

5 is a graph showing excitation wavelength characteristics of a light emitting diode according to a second embodiment of the present invention.

6 is a graph showing a wavelength characteristic distribution showing an emission spectrum distribution according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10,20: light emitting diode 11,21: lead frame

12,22: blue light emitting chip 13,23: red light emitting chip

14 reflector 15 wire

16,24: resin encapsulation agent

The present invention relates to a light emitting diode. More particularly, the present invention relates to a light emitting diode used as a light source of a backlight unit of a medium-large LCD.

In general, a light emitting diode (Light Emitting Diode) is a device that converts electricity into infrared or light by using the characteristics of the compound semiconductor, and has been recently used for various uses such as a light source for the backlight of the liquid crystal panel or a next-generation lighting source.

In order to use as a light source for the backlight of the liquid crystal panel, conventionally, white light is represented by combining three primary colors of light using the emission wavelength of the light emitting chip itself.

However, the above-described structure is a reality that the variation of the color according to the usage environment in the combination of the three colors due to the poor three-color luminous efficiency of the chip itself and the different characteristics of luminous degradation with respect to heat, the manufacturing cost is also extremely high in mass production There is difficulty.

There is an attempt to apply white light using the blue excitation characteristics of the existing YAG-based, TAG-based and Silicate-based phosphors having high efficiency as a backlight light source, but the red color region decreases the efficiency of the phosphor and the red expression region is NTSC ( National television system committee: There is a problem in that it does not realize the high color gamut (GAMUT) because it cannot express the red area of the national television system committee standard.

That is, it is suitable to be used as a light source for backlight of NTSC standard medium / large LCD, and in case of structure using red, green and blue tricolor light emitting chip to realize high color gamut, it secures wide light emission area and therefore wide area of NTSC standard. Although it is possible to provide a light source capable of expressing the color of the light emitting diodes, the light emitting diodes of the three colors can not be provided in the same combination in the same combination due to the different optical characteristics, the yield is low and the manufacturing cost is increased have.

In addition, the technology of emitting white light by exciting phosphors in a single wavelength light emitting chip has a problem of implementing a certain color of the same color and a color of a wide range of red, green, and blue colors, and thus it is difficult to use it as a backlight unit of medium and large sized video media. There is a disadvantage of limitation.

In addition, it is possible to apply a phosphor that has improved the color by improving this, but such a structure is difficult to commercialize due to the poor luminous efficiency.

As described above, in the case of a structure using a light emitting chip of three colors as a white light emitting diode, there is a problem of deviation according to the temperature of the color and a disadvantage of poor light efficiency and high power consumption. It is difficult to reproduce a wide color in the NTSC area, and there is a problem in that it cannot overcome the limitations of resolution and color expression.

The present invention has been made to solve the above problems, an object of the present invention is to combine the advantages of the light emitting diode using the tri-color light emitting chip with the advantages of the light emitting diode using phosphor excitation all colors of the area required in the NTSC The present invention provides a light emitting diode capable of expressing light emitting efficiency, high color reproduction, and low power consumption.

In addition, the present invention has another object to provide a light emitting diode that can increase the yield to minimize the production cost and increase the reliability.

In order to achieve the above object, the light emitting diode includes a lead frame and at least one light emitting chip of two kinds of colors die-bonded to the lead frame among red, green, and blue light emitting chips, and colors other than the two kinds of die bonding. Phosphor emitting light may be mixed to include a resin encapsulant for sealing the light emitting chip.

Accordingly, a wide range of colors can be expressed by the light emitting chips of two colors and the phosphors of the remaining colors, and the light emitting efficiency can be improved.

The two types of light emitting chips die-bonded to the lead frame may be blue light emitting chips and red light emitting chips.

In addition, the phosphor may be a green phosphor.

The phosphor may be a structure that is excited and diverged by a wavelength emitted from at least one of the light emitting chips, and is preferably excited by the wavelength of the blue light emitting chip.

The blue light emitting chip preferably emits in the wavelength range of 445 nm to 460 nm.

Preferably, the red light emitting chip emits light at a wavelength of 620 nm to 650 nm.

The green phosphor is preferably to be emitted in the wavelength range of 520nm ~ 540nm.

In addition, the excitation wavelength of the phosphor is preferably 445nm ~ 460nm, more preferably may have a structure that is not excited in the wavelength band of 500nm or more.

The light emitting diode may include a structure in which a reflector is injection molded in a lead frame and the transmissive resin encapsulant is filled in the reflector, or a structure in which the resin encapsulant is transfer molded in a lead frame on which a light emitting chip is mounted, or a lamp. It does not specifically limit.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a plan view of a light emitting diode according to a first embodiment of the present invention, Figure 2 is a side cross-sectional view of the light emitting diode according to the first embodiment of the present invention.

According to the drawings, the light emitting diode 10 of the present embodiment includes a lead frame 11 including a pair of anode lead frames and cathode lead frames, and A blue light emitting chip 12, a red light emitting chip 13, and a resin formed on the upper side of the lead frame 11, which are attached to the die pad through a die adhesive, surround the light emitting chips 12 and 13. The reflector 14, the conducting wire 15 connected between the light emitting chips 12 and 13 and the lead frame 11, and green phosphors excited by the emission wavelength of the blue light emitting chip and emitted green And a resin encapsulant 16 filled in the reflector.

In the present embodiment, three light emitting chips are mounted in one light emitting diode 10, two are blue light emitting chips 12 emitting blue light, and the other is red light emitting red light. Chip 13.

The number of the blue light emitting chip and the red light emitting chip for one light emitting diode is not limited to the above embodiment and various combinations are possible.

In addition, the three light emitting chips 12 and 13 are connected to the lead frame 11 through a conducting wire 15 so as to be configured in a series circuit with each other. This series connection structure is the same as the circuit structure of the conventional light emitting diode, and provides the advantage that the light emitting diode chip of the present embodiment can be manufactured using the same without changing the conventional manufacturing process.

In FIG. 1, the three light emitting chips 12 and 13 are arranged in a triangular shape, but the arrangement structure is not particularly limited and may be arranged in various forms.

The blue light emitting chip 12 is made of GaN-based or InGaN-based elements, and emits light in the wavelength range of 445 nm to 460 nm.

In addition, the red light emitting chip 13 is made of an InGap-based element and emits light in a wavelength range of 620 nm to 650 nm.

The resin encapsulant 16 is a liquid or solid resin mixture in which a light-transparent epoxy resin and a phosphor are mixed, and the mixing ratio of the epoxy resin and the phosphor is a weight ratio of the phosphor mixed within 15% of the resin mixture. Is preferred.

When the mixing ratio is higher than 15%, the luminous efficiency is lowered as compared with the conventional one, and the reproduction pseudo-value of color is lowered by extremely reducing the emission of blue which is the source in extracting red, green, and blue.

In addition, in the present embodiment, the green phosphor is made of a silicate-based material mainly containing strontium silicate. In addition to the material, any material that satisfies the following characteristics will be applicable as the green phosphor.

The green phosphor mixed with the resin encapsulant 16 has a structure that is excited by only one type of wavelength of the blue light emitting chip 12 to emit light. Accordingly, the green phosphor is excited in the wavelength range of 445 nm to 460 nm, which is the wavelength band of the blue light emitting chip 12, and is not excited in the wavelength range of 500 nm or more, and is excited in the specific wavelength band to emit light in the wavelength range of 520 nm to 540 nm. do.

In addition, the green phosphor has one or more peak wavelengths in the emission spectrum, peaks are distributed in the green wavelength region and the red wavelength region, and the red light emission efficiency does not exceed 20% of the green light emission efficiency.

This is because the green phosphor is a combination of only blue and green wavelengths can implement a constant color coordinates under the most ideal conditions and the color change with respect to the amount of the phosphor is extremely small.

When the spectrum of the green phosphor is distributed only in the green wavelength range or when the red luminous efficiency exceeds 20% of the green luminous efficiency, the color becomes a combination of three colors of the source wavelength of the light emitting chip and the green and red wavelengths of the phosphor. Diverse distributions make it difficult to achieve consistent colors.

4 is a graph showing excitation spectral characteristics of the green phosphor, and FIG. 5 is a graph showing a spectral distribution in which the green phosphor emits light in response to an excitation wavelength.

As can be seen from the above graph, the green phosphor has a property of not being excited in a wavelength range of 500 nm or more, and emits in a wavelength of 525 nm to 540 nm in response to an excitation wavelength of 445 nm to 460 nm, and does not emit light in a wavelength of 620 nm or more. It can be seen that.

Accordingly, the light emitting diode is excited by a specific wavelength emitted from the blue light emitting chip and the red light emitting chip and a wavelength emitted from the blue light emitting chip, and the wavelength emitted from the green phosphor is combined with each other. It emits light in the wide wavelength range of green.

FIG. 6 is a graph illustrating light emission wavelengths of light emitting diodes according to the present embodiment. As can be seen from the graphs, blue, red, and green wavelength bands are clearly identified, and each color emits light in a wide wavelength region satisfying the NTSC standard. It can be seen that.

Meanwhile, FIG. 3 illustrates a structure in which an epoxy resin is molded as another embodiment of the light emitting diode.

According to the drawings, the light emitting diode 20 of the present embodiment includes a lead frame 21 including a pair of anode lead frames and cathode lead frames, and the lead frames 21. The green phosphor that is excited by the emission wavelength of the blue light emitting chip 22, the red light emitting chip 23, and the blue light emitting chip 22, which is attached to the die pad through the die adhesive, emits green. A resin encapsulant 24 is mixed and transferred to the lead frame 21.

The resin encapsulant 24 may be understood as a resin mold molded into the lead frame 21 to form an outline.

Except for the structure of the resin encapsulant 24 coupled to the lead frame 21, the light emitting diode 20 according to the present embodiment has the same characteristics and operation as those described in Example 1 except for the structure of the light emitting chip or the phosphor. Therefore, the detailed description will be omitted below.

Hereinafter, referring to Example 1, a manufacturing process of the light emitting diode 10 will be described. Among the light emitting chips of three primary colors, the blue light emitting chip 12 and the red light emitting chip 13 may have a lead frame 11 through a die adhesive. Die bonding on the wire) and wire bonding with the gold conducting wire 15 for electrical connection with the leadframe 11.

In addition, a resin encapsulant 16 is prepared by mixing a green phosphor with a transparent epoxy resin, and the resin encapsulant 16 mixed with phosphor is injected into a reflector 13 formed on the lead frame 11 and filled. Alternatively, in the second embodiment, the lead frame 21 is transfer molded.

When the resin is cured through the resin encapsulation process, each device is individualized through a trimming or forming process, and then a light emitting diode 10 having a broad wavelength band of three primary colors and a uniform color gamut is formed through an electrical and optical characteristic selection process. It becomes possible to manufacture.

While exemplary embodiments of the present invention have been shown and described as described above, various modifications and other embodiments may be made by those skilled in the art. Such modifications and other embodiments will be considered and included in the appended claims without departing from the true spirit and scope of the invention.

As described above, according to the present invention, it is possible to obtain a light emitting diode capable of expressing a high yield and a wide range of colors while minimizing manufacturing costs by taking advantage of light emitting diodes using tricolor light emitting chips and light emitting diodes using phosphors.

In addition, the conventional series circuit configuration can be used as it is, there is an advantage that a separate design for circuit improvement is unnecessary.

In addition, the color can be adjusted more easily by controlling only two kinds of light emitting chips, and the color adjustment is easier. By being insensitive to change, color reproduction in the same package can be kept constant even if the conditions of the use environment are changed.

Claims (15)

In the light emitting diode used as the light source of the backlight unit of the liquid crystal display device, The light emitting diode is mixed with a lead frame, a red light emitting chip die-bonded to the lead frame, a blue light emitting chip, and a green phosphor excited by the light emission wavelength of the light emitting chip to emit green light to seal the light emitting chip. Including resin encapsulant, The resin encapsulation agent is made of a resin mixture in which an epoxy resin and a green phosphor are mixed, and the green phosphor is mixed within 15% of the resin mixture by weight ratio, and excited in a wavelength range of 445 nm to 460 nm to a wavelength of 520 nm to 540 nm. A light emitting diode that emits light, has one or more peak wavelengths in an emission spectrum, has peaks distributed in a green wavelength region and a red wavelength region, and has a red luminous efficiency that does not exceed 20% of the green luminous efficiency. The light emitting diode of claim 1, wherein the phosphor is excited only at a wavelength band emitted from one type of light emitting chip among the two types of light emitting chips. delete delete The method of claim 1, And the phosphor is excited to the emission wavelength band of the blue light emitting chip. The method of claim 5, wherein The blue light emitting chip emits light with a wavelength of 445 nm to 460 nm. The method of claim 5, wherein The red light emitting chip emits light with a wavelength of 620 nm to 650 nm. delete delete The method of claim 1, A light emitting diode having a structure in which a reflector is injection molded in the lead frame and the resin encapsulation agent is filled in the reflector. The method of claim 1, A light emitting diode having a structure in which the resin encapsulant is transfer molded to the lead frame. The method of claim 1, The light emitting diodes of the plurality of light emitting chips connected in series circuit. The method of claim 1, The green phosphor is a light emitting diode made of a silicate (Silicate) material mainly composed of Strontium Silicate (Strontium Silicate). delete delete

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