KR102421222B1 - Led package and back light unit including the led package - Google Patents

Abstract

The present embodiments relate to an LED package capable of high color reproduction and a backlight unit using the LED package as a light source, comprising a first LED chip emitting light of a first color and a second LED chip emitting light of a second color. By configuring the LED package including the first phosphor and the second phosphor having different peak wavelengths in the wavelength band of the third color, it is possible to express colors with high color purity in the red, green, and blue color regions. Provides an LED package that can realize high color reproduction.

Description

LED package and backlight unit including LED package {LED PACKAGE AND BACK LIGHT UNIT INCLUDING THE LED PACKAGE}

The present embodiments relate to an LED package and a backlight unit including the LED package.

As the information society develops, various user demands for display devices that display images are increasing, and liquid crystal display devices, plasma display devices, and organic light emitting display devices are increasing. Various display devices such as display devices are being used.

Among these display devices, a liquid crystal display device displays color and grayscale by arranging liquid crystal on a display panel and changing the arrangement of the liquid crystal according to a voltage applied to the liquid crystal. Here, a structure for irradiating light to the liquid crystal disposed on the display panel, such as a backlight unit, is disposed on the display panel.

The backlight unit may include a light source assembly in which a light source is disposed to emit light, and a light guide plate to guide the light emitted from the light source assembly to the display panel.

That is, the light emitted from the light source disposed in the light source assembly is guided by the light guide plate and irradiated to the liquid crystal disposed in the display panel, and a color, etc. is expressed according to the arrangement state of the liquid crystal.

Therefore, in order to enable high color reproduction of images displayed by the liquid crystal display device, the light source disposed in the light source assembly must be capable of supporting high color reproduction. There is a problem that it is difficult to support reproduction.

An object of the present embodiments is to provide a light source capable of supporting high color reproduction in a liquid crystal display device requiring high resolution and high color reproduction and a backlight unit including the same.

In addition, by providing an LED package including an LED chip and a phosphor configured to support high color reproduction, it is to provide an LED package that can be used in various fields such as lighting and medical fields as well as a backlight unit of a liquid crystal display device.

In one aspect, the present embodiments provide an LED package including a first LED chip emitting light of a first color and a second LED chip emitting light of a second color different from the first color.

The LED package includes a first phosphor having a first wavelength as a peak wavelength in a wavelength band of a third color different from a first color, a second color, and a second wavelength different from the first wavelength in a wavelength band of the third color. A second phosphor having a peak wavelength may be included.

In another aspect, the present embodiments include a light source assembly on which one or more LED packages are disposed, and a light guide plate for guiding light emitted from the light source assembly, wherein the one or more LED packages include a plurality of light sources emitting light of different colors. Provided is a backlight unit including an LED chip and a plurality of phosphors having different peak wavelengths in a wavelength band of the same color.

According to the present embodiments, by providing an LED package including a plurality of LED chips emitting light of different colors and a plurality of phosphors having different peak wavelengths in a wavelength band of the same color, an LED capable of high color reproduction to provide a package.

In addition, by using an LED package capable of high color reproduction as a light source of a backlight unit, a liquid crystal display device capable of realizing high color reproduction is provided.

1 is a diagram illustrating a schematic configuration of a display device according to the present exemplary embodiment.
2 is a diagram illustrating a schematic configuration of a backlight unit in the display device according to the present exemplary embodiment.
3 is a view showing an example of an LED package according to the present embodiments.
FIG. 4 is a view for explaining a method of implementing a color by the LED package shown in FIG. 3 .
5 and 6 are views illustrating light intensity according to colors implemented by the LED package shown in FIG. 3 .
FIG. 7 is a view showing color gamut by the LED package shown in FIG. 3 .
8 and 9 are views showing another example of the LED package according to the present embodiments.
10 and 11 are views illustrating light intensity according to colors implemented by the LED package shown in FIGS. 8 and 9 .
12 is a view showing color gamut by the LED package shown in FIGS. 8 and 9 .

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the nature, order, order, or number of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It will be understood that each component may be “interposed” or “connected”, “coupled” or “connected” through another component.

1 shows an example of the configuration of the display apparatus 100 according to the present embodiments.

Referring to FIG. 1 , the display apparatus 100 according to the present exemplary embodiments includes a display panel 110 displaying an image, a backlight unit irradiating light to the display panel 110 , and a display. It may include a chassis unit (Chassis Unit) for fastening each component of the apparatus 100, and the like.

The display panel 110 may include a first substrate 111 on which a thin film transistor and various signal lines are disposed, and a second substrate 112 on which a color filter is disposed. have.

The backlight unit is disposed under the display panel 110 and may include a light source (not shown) and a light guide plate 130 guiding the light emitted from the light source to the display panel 110 .

Such a backlight unit may be of a direct type in which the light source is positioned below the display panel 110 , and may be of an edge type in which the light source is positioned at the side of the display panel 110 .

The backlight unit may include at least one sheet 120 such as a diffusion sheet for diffusing light on the upper portion of the light guide plate 130 , and a reflector 140 under the light guide plate 130 to increase light efficiency, etc. may include

The chassis unit may serve to fasten or protect components such as the display panel 110 and the backlight unit, and may include a guide panel 150 and a cover bottom 160 .

The display apparatus 100 according to the present exemplary embodiments may further include a driving circuit for driving the display panel 110 .

Such a driving circuit may be composed of a plurality of driver integrated circuits (Driver IC) for operating the display panel 110 and a printed circuit board to which various circuit elements are attached.

Here, the plurality of driver integrated circuits may include at least one gate driver IC and at least one data driver IC.

The plurality of driver integrated circuits may be electrically connected to the first substrate 111 .

For example, the driver integrated circuit may be mounted on a film and connected to the first substrate 111 in a tape carrier package (TCP) mounting method using a tape automated bonding (TAB) technology. Alternatively, the driver integrated circuit may be connected to the first substrate 111 by a chip on glass (COG) mounting method that is directly connected to a bonding pad formed on the first substrate 111 .

The above-described driving circuit may further include a controller that generates an electric signal for controlling a plurality of driver integrated circuits and controls a digital data signal input from the outside.

FIG. 2 illustrates an example of a backlight structure when the backlight unit is an edge type in the display device 100 illustrated in FIG. 1 .

Referring to FIG. 2 , the backlight unit according to the present embodiments may include a light source assembly 200 in which a plurality of light sources 210 are disposed, and a light guide plate 130 for guiding light emitted from the light sources 210 . can

The light source assembly 200 may be disposed on one side of the display panel 110 , and as shown in FIG. 2 , may be disposed on both sides of the display panel 110 .

A plurality of light sources 210 may be disposed in the light source assembly 200 , and the light sources 210 include Electro luminescence (EL), Cold Cathode Fluorescent Lamp (CCFL), Hot Cathode Fluorescent Lamp (HCFL), and Light Emitting Diode (LED). ) may be used.

Among these light sources 210, the LED has the advantages of low power consumption and excellent luminous efficiency, and thus the use thereof is gradually increasing.

Such an LED may constitute an LED package including an LED chip emitting light and a plurality of phosphors.

3 shows an example of the structure of the LED package used as the light source 210 in the backlight unit according to the present embodiments.

Referring to FIG. 3 , the LED package according to the present embodiments may include a plurality of LED chips emitting blue light, a yellow phosphor, and a red phosphor.

For example, an LED chip emitting blue light may emit light having a peak wavelength of 446 nm, a yellow phosphor may have a peak wavelength of 540 nm, and a red phosphor may have a peak wavelength of 630 nm.

The LED package implements a blue color through light emitted from an LED chip that emits blue light. In addition, the light emitted from the LED chip excites the yellow phosphor and the red phosphor to realize green and red colors.

4 to 7 show a method of implementing a color by the LED package shown in FIG. 3 and a color gamut by the implemented color.

Referring to FIG. 4 , the LED package according to the present embodiments exhibits a blue color by an LED chip emitting light having a peak wavelength of 446 nm. Then, the light emitted from the LED chip excites the yellow phosphor having a peak wavelength of 540 nm to display a green color. In addition, light emitted from the LED chip excites a red phosphor having a peak wavelength of 630 nm to exhibit a red color.

That is, a blue color is realized through an LED chip that emits blue light, and a green color and a red color are realized through the light generated when the light emitted from the LED chip excites the yellow phosphor and the red phosphor.

At this time, the green and red colors are realized by exciting the yellow phosphor and the red phosphor through the light emitted from the LED chip that emits blue light. There is a problem in that it is difficult to implement color.

5 and 6 show the intensity of color implemented by the LED package shown in FIG. 3 , and FIG. 7 shows the color gamut by the LED package shown in FIG. 3 .

Referring to FIG. 5 , since the LED package according to the present embodiments emits light using an LED chip corresponding to a blue color, the intensity of light appears high in a wavelength band corresponding to the blue color.

On the other hand, since the yellow phosphor and the red phosphor are excited using the light emitted by the LED chip that emits blue light to realize the green and red colors, the intensity of light in the wavelength bands corresponding to the green and red colors is increased. appear low.

Accordingly, as shown in FIG. 6 , the intensity of light appears to be high in the wavelength band corresponding to the blue color, whereas the intensity of light appears to be low in the wavelength band corresponding to the green color and the red color.

7 shows colors that can be implemented by the LED package according to the present embodiments according to the intensity of such light.

Referring to FIG. 7 , in the case of a blue color, a blue color having a relatively high color purity can be expressed.

However, in the case of green and red colors, a region with high color purity cannot be expressed, so there is a limit when high color reproduction with higher color purity than general color reproduction is required (84.5% color reproduction based on Adobe RGB).

The LED package according to the present embodiments provides an LED package capable of high color reproduction with high color purity by adjusting a color of light emitted by an LED chip and a peak wavelength of a phosphor included in the LED package differently.

8 shows another example of the structure of the LED package according to the present embodiments.

Referring to FIG. 8 , the LED package according to the present embodiments may include a first LED chip emitting light of a first color and a second LED chip emitting light of a second color different from the first color. can

In addition, a phosphor having a peak wavelength in a wavelength band of a third color different from the first color and the second color may be included.

Here, the phosphor having a peak wavelength in the wavelength band of the third color may be composed of two types of phosphors having different peak wavelengths in the corresponding wavelength band.

That is, by configuring an LED package using an LED chip having four different peak wavelengths and a phosphor, a deep color with high color purity can be realized.

For example, the first LED chip emitting light of the first color may be a blue LED chip emitting light of a blue color having a peak wavelength of 446 nm. Accordingly, a blue color is implemented using the light emitted by the first LED chip.

The second LED chip emitting light of the second color may be a green LED chip emitting light of a green color having a peak wavelength of 520 nm. Accordingly, a green color is implemented using the light emitted by the second LED chip.

Unlike the above-described LED package that excites a yellow phosphor to realize a green color, a green color with high color purity can be realized by using the light emitted from the LED chip to implement a green color.

The first phosphor and the second phosphor included in the LED package may be red phosphors having a peak wavelength in a red wavelength band.

In this case, the phosphor may be composed of a KSF phosphor (first phosphor) having a peak wavelength of 630 nm and a deep red phosphor (second phosphor) having a peak wavelength of 670 nm.

Here, the KSF phosphor refers to a type of inorganic phosphor, and refers to a red phosphor having a peak wavelength of 630 nm in the LED package of FIG. 3 .

And, the deep red phosphor means a red phosphor having a peak wavelength of 670 nm longer than a peak wavelength of 630 nm in the LED package of FIG. 3 .

That is, compared to the LED package shown in FIG. 3, the red phosphor is composed of a first phosphor having a peak wavelength of 630 nm and a second phosphor having a peak wavelength of 670 nm, so that a color with high color purity in the red region is obtained. make it possible to implement

The first phosphor and the second phosphor may be included in the same ratio or may be included in different ratios.

FIG. 9 shows an example of a case in which different ratios of the first phosphor and the second phosphor are included in the LED package shown in FIG. 8 .

Referring to FIG. 9 , a first LED chip emitting light of a first color and a second LED chip emitting light of a second color are included. In addition, in the wavelength band of the third color, a first phosphor having a peak wavelength of a first wavelength and a second phosphor having a peak wavelength of a second wavelength are included.

Here, the first LED chip may be an LED chip emitting blue light having a peak wavelength of 446 nm, and the second LED chip may be an LED chip emitting green light having a peak wavelength of 520 nm.

In addition, the first phosphor and the second phosphor are red phosphors having different peak wavelengths in the red wavelength band. The first phosphor may be a phosphor having a peak wavelength of 630 nm, and the second phosphor may be a phosphor having a peak wavelength of 670 nm. have.

Here, a ratio of the first phosphor having a peak wavelength of 630 nm may be higher than a ratio of the second phosphor having a peak wavelength of 670 nm.

That is, blue and green colors are implemented through the first LED chip emitting blue light and the second LED chip emitting green light, and the light emitted from the first LED chip and the second LED chip. to excite the red phosphor to realize the red color, but to improve the color purity of the red color by including a part of the deep red phosphor having a peak wavelength of 670 nm.

Therefore, the blue color and green color enable high color reproduction through the light emitted from the LED chip, and the red color is a red color with high color purity by mixing and including red phosphors having different peak wavelengths in the red color wavelength band. to be able to implement

10 to 12 show the intensity of the color expressed by the LED package shown in FIGS. 8 and 9 and the area of the implemented color.

Referring to FIGS. 10 and 11 , the LED package according to the present embodiments realizes blue color through the first LED chip emitting blue color light, so that light exhibiting high intensity in the blue color wavelength band is emitted. radiate

Then, the green color is implemented through the second LED chip that emits the green light, and light having high intensity in the green color wavelength band is emitted.

In addition, the LED package includes a mixture of a first phosphor and a second phosphor having different peak wavelengths in a red wavelength band, and is formed with the first phosphor and the second phosphor by light emitted from the first LED chip and the second LED chip. By excitation of the second phosphor to realize a red color, light having a high intensity in a wavelength band of the red color is emitted.

Accordingly, as shown in FIG. 11, by increasing the intensity of light emitted not only from the blue color area, but also from the green color area and the red color area, it is possible to reproduce a color with high color purity in the green color area and the red color area. make it possible

As shown in FIG. 12 , it is possible to provide an LED package capable of high color reproduction (99.5% color reproduction based on Adobe RGB) by enabling color reproduction in an area of high color purity of green color and area of high color purity of red color. ).

According to the present embodiments, an LED package including a plurality of LED chips emitting light of different colors and a plurality of phosphors having different peak wavelengths in a wavelength band of a color different from that of the light emitted by the LED chip. By configuring it, an LED package capable of high color reproduction in red, green, and blue color areas is provided.

Such an LED package may be used as a light source of a backlight unit irradiating light from the display device 100 to the display panel 110 .

In addition, it can be used for devices requiring high color reproduction, such as lighting devices or medical equipment, as well as the display device 100 to realize colors with high color purity.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. In addition, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, so the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: display device 110: display panel
111: first substrate 112: second substrate
120: sheet 130: light guide plate
140: reflector 150: guide panel
160: cover bottom 200: light source assembly
210: light source (LED package)

Claims (6)

a first LED chip emitting light of a first color;
a second LED chip emitting light of a second color different from the first color;
a first phosphor emitting light having a first wavelength as a peak wavelength in a wavelength band of a third color different from the first color and the second color; and
a second phosphor emitting light having a second wavelength different from the first wavelength as a peak wavelength in the wavelength band of the third color;
The first phosphor and the second phosphor are dispersedly disposed on the first LED chip and the second LED chip, and the light of the first color emitted by the first LED chip and the second LED chip Excite a part of the emitted light of the second color to emit light of the third color,
The first wavelength and the second wavelength are 600 nm or more, the second wavelength is greater than the first wavelength, and the ratio of the second phosphor to the total phosphor is smaller than the ratio of the first phosphor.
The method of claim 1,
The wavelength of the first color and the wavelength of the second color are shorter than the wavelength of the third color LED package.
The method of claim 1,
The first wavelength of the first phosphor is longer than a wavelength of the first color and a wavelength of the second color and is shorter than the second wavelength of the second phosphor.
delete The method of claim 1,
The first LED chip emits blue light, the second LED chip emits green light, and the first phosphor and the second phosphor are red phosphors having different peak wavelengths.
A backlight unit comprising a light source assembly in which the LED package of any one of claims 1 to 5 is disposed, and a light guide plate guiding light emitted from the light source assembly.

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