KR100591687B1 - Multi-chip LED package with improved color scheme and backlight unit using the same - Google Patents

Abstract

Disclosed are a multi-chip LED package and a backlight unit employing the same.

The disclosed backlight unit includes a light emitting diode package in which a plurality of light emitting diode chips are packaged as a module, the chip bonding pad comprising: a chip bonding pad; Light emitting diode chips emitting light of at least four different wavelengths disposed on the chip bonding pads; Leads electrically connected to the light emitting diode chips by wire bonding; And a cavity formed above the light emitting diode chips, wherein the cavity is filled with a transparent material to form a light emitting window.

The color gamut may be enlarged through the light emitting diode chips emitting light of at least four different wavelengths, and color reproduction may be closer to natural colors.

Description

Multi-chip light emitting diode package developing color gamut and back light unit employing the same}

1 illustrates a light emitting diode light source disclosed in US Pat. No. 6,540,377 B1.

2A is a plan view of a multi-chip LED package according to a first embodiment of the present invention.

FIG. 2B is a cross-sectional view taken along the line A-A of FIG. 2A.

FIG. 3 illustrates a color scheme when a red light emitting chip, first and second green light emitting chips, and a blue light emitting chip are provided in the multi-chip LED package shown in FIG. 2A.

4 shows a modification of the multi-chip light emitting diode package according to the first embodiment of the present invention.

FIG. 5 illustrates a color scheme when a red light emitting chip, a green light emitting chip, a blue light emitting chip, and a yellow light emitting chip are provided in the multi-chip LED package shown in FIG. 4.

6 shows a modification of the multi-chip light emitting diode package according to the first embodiment of the present invention.

7 is a plan view of a package of a multi-chip light emitting diode according to a second embodiment of the present invention.

FIG. 8 illustrates a color scheme when the multi-chip LED package shown in FIG. 7 includes a red light emitting chip, a green light emitting chip, a blue light emitting chip, a yellow light emitting chip, and a cyan light emitting chip.

9 schematically illustrates a light metering backlight unit according to the present invention.

10A illustrates a light source unit employed in a direct type backlight unit according to the present invention.

10B schematically illustrates a direct backlight unit according to the present invention.

<Description of main part of drawing>

50 ... light guide plate, 60 ... light source

65,120 ... Printed Circuit Board, 70,70 ', 70 "... Light Emitting Diode Package

91a, 91b, 91c, 91d, 101a, 101b, 101c, 101d, 111a, 111b, 111c, 111d, 111e ... light emitting diode chip

92,105 ... body, 93,104 ... cavity

94,107 ... Light Emitting Window, 97,102a, 102b, 102c ... Chip Bonding Pad

98a, 98b, 98c, 103a, 103b, 103d, 113a, 113b, 113c, 113d ... lead

The present invention relates to a multi-chip light emitting diode package and a backlight unit employing the same. More particularly, the present invention relates to a light emitting diode packaged by packaging a plurality of light emitting diode chips emitting light having different wavelengths of at least 4 wavelengths. A package and a backlight unit employing the same.

A liquid crystal display device, which is a kind of light-receiving flat panel display used in notebooks, desktop computers, LCD-TVs, mobile communication terminals, etc., does not have its own light emitting capability, and thus forms an image by selectively transmitting illumination light emitted from the outside. To this end, a backlight unit for illuminating light is provided on the back of the liquid crystal display.

The backlight unit is classified into a direct light type and an edge light type according to the arrangement of the light sources. The direct type is a method of directly irradiating light to the liquid crystal panel from a light source provided directly below the liquid crystal panel, and the photometric type is a method of reflecting light emitted from the side of the light guide plate through the light guide plate to be directed to the liquid crystal panel.

The direct type backlight unit is suitable for a large display, and the metering type backlight unit is suitable for a small and medium size display because its thickness is relatively thin and the amount of light is small. Light emitting diodes are widely used in these backlight units because of their low power consumption, long life, fast response, and environmental friendliness. Existing light emitting diode packages are mixed with blue light emitting chips and yellow phosphors, or packaged with red light emitting chips, green light emitting chips, and blue light emitting chips, respectively, by mixing the light emitted from them to realize white color. In the former case, since the red wavelength is weak, it is difficult to reproduce the vivid red color even though passing through the color filter. In the latter case, the color expression is clearer and freer than in the former case.

Recently, many packages have been developed in which three light emitting diode chips are packaged as one without separately configuring a red light emitting chip, a green light emitting chip, and a blue light emitting chip.

A light emitting device using a conventional light emitting diode is disclosed in US Pat. No. 6,540,377 B1. As shown in Fig. 1, the light emitting device 1 includes a printed circuit board 2A for mounting an LED and a plurality of LED elements 3F, 3G, and 3B disposed on the surface 2a of the printed board 2A. ), A case 4 in which the opening 4a is provided to surround the plurality of LED elements, and a charging member 5 for packing the plurality of LED elements and filling the inside of the opening 4a of the case 4. Has The printed circuit board 2A has individual leads 6R, 6G, 6B for each of R, G, and B, and a common lead 6C common to a plurality of LED elements. The leads 6R, 6G, 6B, and 6C have electrode faces 6R ₁ , 6G1, 6B ₁ , 6C ₁ , extensions 6R ₂ , 6G ₂ , 6B ₂ , 6C ₂ , and connections 6R ₃ , 6G _3. , 6B ₃ , 6C ₃ ).

The LED element 3 is composed of a blue LED element 3B, two red LED elements 3R and 3R disposed on both sides thereof, and two green LED elements 3G and 3G. Here, in order to compensate for the lower luminous efficiency of red and green than blue, a plurality of LED elements of the same color can be provided to obtain uniform white light emission characteristics. However, in such a structure, there is a problem that the color gamut is limited because the color reproduction by the three wavelengths of red light, green light, and blue light is limited, and thus there is a limit to satisfy the requirement to implement a full color image.

The present invention has been made to solve the above problems, and provides a light emitting diode package packaged with light emitting diode chips emitting at least four different wavelengths of light to improve color gamut and a backlight unit employing the same. There is a purpose.

In order to achieve the above object, in a light emitting diode package in which a plurality of light emitting diode chips are packaged as a module,

Chip bonding pads; Light emitting diode chips emitting light of at least four different wavelengths disposed on the chip bonding pads; Leads electrically connected to the light emitting diode chips by wire bonding; It is formed to have a cavity above the light emitting diode chips, the cavity is filled with a transparent material to form a light emitting window; including, characterized by extending the color by the light emitted from the light emitting diode chips.

In order to achieve the above object, a light emitting diode package according to the present invention includes a light emitting diode package in which a plurality of light emitting diode chips are packaged as a module.

One chip bonding pad; First and second leads and third leads provided in pairs on both sides of the chip bonding pad; A first light emitting diode chip disposed on the chip bonding pad, the first light emitting diode chip connected to the first lead to emit red light, and a second light emitting diode chip connected to the second lead to emit the first green light, the second lead A third light emitting diode chip connected to the first green light and emitting a second green light in a wavelength region different from the first green light, and a fourth light emitting diode chip connected to the third lead and emitting blue light; It is formed to have a cavity above the light emitting diode chips, the cavity is filled with a transparent material to form a light emitting window; including, characterized by extending the color by the light emitted from the light emitting diode chips.

In order to achieve the above object, a light emitting diode package according to the present invention includes a light emitting diode package in which a plurality of light emitting diode chips are packaged as a module.

First, second and third chip bonding pads arranged in a line to insulate each other; First, second, and third leads disposed adjacent to the first, second, and third chipbonding pads; A first light emitting diode chip disposed on the first chip bonding pad and connected to the first lead to emit red light, and a second disposed on the second chip bonding pad and connected to the second lead to emit first green light A light emitting diode chip, a third light emitting diode chip emitting second green light in a wavelength region different from the first green light, and a fourth light emitting diode chip disposed on the third chip bonding pad and connected to a third lead to emit blue light ; It is formed to have a cavity above the light emitting diode chips, the cavity is filled with a transparent material to form a light emitting window; including, characterized by extending the color by the light emitted from the light emitting diode chips.

A multi-chip LED package and a backlight unit employing the same according to the present invention will be described in detail with reference to the accompanying drawings.

The multi-chip LED package according to the present invention is configured as a module by packaging LED chips emitting light of at least four different wavelengths. By using light of various wavelength bands, color is extended to express a color gamut.

The multi-chip LED package 70 according to the first embodiment of the present invention includes the first, second, third and fourth LED chip 91a of different wavelengths as shown in FIGS. 2A and 2B. 91b, 91c, 91d are provided. First, second, third, and fourth light emitting diode chips 91a, 91b, 91c, and 91d are arranged in one chip bonding pad 97, and are insulated from the chip bonding pad 97. Three pairs of leads 98a, 98b and 98c are provided. The first to fourth LED chips may be arranged in various forms, but an example of the first to fourth LED chips will be described. The three pairs of leads 98a, 98b and 98c are configured by pairing a positive terminal and a negative terminal which are disposed to face each other with the chip bonding pad 97 interposed therebetween. The first light emitting diode chip 91a is connected to the first lead 98a by wire bonding, and the second and third light emitting diode chips 91b and 91c are connected to the second lead 98b by wire bonding. The fourth LED chip 91d is connected in parallel to the third lead 98c. The heat dissipation extension pads 99 extend from both sides of the chip bonding pads 97 to escape the first to third leads to dissipate heat generated from the chips. The heat dissipation extension pad 99 preferably has a larger width than the chip bonding pad 97.

As shown in FIG. 2B, the first to fourth light emitting diode chips 91a, 91b, 91c, and 91d have a body 92 made of a plastic resin having a cavity 93 thereon. The cavity 93 is formed of a light emitting window 94 filled with a transparent material capable of transmitting light. The first to fourth LED chips are arranged in a line in the chip bonding pad 97 that forms the bottom surface of the cavity 93, and the LED window 94 includes the LED chips arranged in a line. It is preferably formed in a rectangular shape having a long length in the direction.

The first to fourth LED chips 91a, 91b, 91c, and 91d emit light having different wavelengths. For example, the first LED chip 91a emits red light. The second LED chip 91b may emit first green light, the third LED chip 91c may emit second green light, and the fourth LED chip 91d may emit blue light. . Here, in order to widen the color gamut, it is preferable to configure the wavelength range of the first green light and the second green light differently. More preferably, the first green light and the second green light have a wavelength difference within a range of 15-40 nm.

Since the multi-chip LED package is mixed in the package and emitted, no space for mixing is required. In this case, the distance between the light emitting diode chips is preferably as small as possible, and in order to emit light with a wider directivity, the light emitting diode chips are arranged in a row and the light emitting window is preferably formed long in the direction in which the light emitting diode chips are arranged. . The light emitting window 94 may be manufactured in various forms, but may be formed to have a rectangular shape, for example.

FIG. 3 illustrates color coordinates of a light emitting diode package composed of a red chip, a first green chip, a second green chip, and a blue chip, and includes color gamut, red light (R), and green light according to the National Television System Committee (NTSC) standard. (G), the color gamut by the tricolor light of the blue light (B), the red light (R), the first green light (G1), the second green light (G2), and the color gamut by the blue light (B) are shown in comparison. The color rendering between these is summarized as follows.

   color          Color coordinates   Wavelength (Wd)   Color rendering       x       y   NTSC     R     0.67     0.33     610    100%     G     0.21     0.71     535     B     0.14     0.08     470   RGB     R     0.7     0.3     625    108%     G     0.2     0.7     530     B     0.13     0.07     470 RG ₁ G ₂ B     R     0.7     0.3     625    126% G ₁     0.2     0.7     530 G ₂     0.1     0.7     510     B     0.13     0.07     470

It can be seen that the color gamut is enlarged by the area indicated by A in FIG. 3.

In addition, in order to study the desired color gamut, the wavelength of each LED chip may be appropriately selected and configured.

For example, the first light emitting diode chip 91a emits a first red light, the second light emitting diode chip 91b emits a second red light having a wavelength different from that of the first red light, and a third light emitting diode chip. Reference numeral 91c may emit green light, and the fourth LED chip 91d may be configured to emit blue light.

In FIG. 2A, an example in which the second and third LED chips 91b and 91c are connected in parallel is illustrated, but as shown in FIG. 4, the first to fourth LED chips are connected to each other in series to independently connect each chip. It is possible to drive with. In this structure, the first LED chip 91a is red light, the second LED chip 91b is green light, the third LED chip 91c is blue light, and the fourth LED chip 91d is yellow light. It can be configured to emit light. FIG. 5 shows a color scheme when the light emitting diode package is configured in this manner.

On the other hand, a modification according to the first embodiment of the present invention is shown in FIG. Fig. 6A shows a plan view of the package, Fig. 6B shows a side cross-sectional view, and Fig. 6C shows a side cross-sectional view.

The light emitting diode package 70 'has first, second and third chip bonding pads 102a, 102b and 102c insulated from each other on the bottom surface of the cavity 104 formed in the center of the body 105. And a first light emitting diode chip 101a on the first chip bonding pad 102a and a second and third light emitting diode chip 101b and 101c on the second chip bonding pad 102b. The fourth LED chip 101d is disposed on the chip bonding pad 102c. The first light emitting diode chip 101a is wire-bonded to the first lead 103a, the second and third light emitting diode chips 102b and 102c are wire-bonded to the second lead 103b, and the fourth light emission. The diode chip 102d is wire bonded to the third lead 103c. In this case, the chip bonding pads are divided into three so that the LED chips are driven independently.

The light emitting window 107 formed by filling the inside of the cavity 104 with a transparent material is formed to have an elongated shape in a direction in which the first to fourth LED chips 101a, 101b, 101c, and 101d are arranged in a line. It has a rectangular shape. Then, the heat generated from the light emitting diode chips is provided with heat dissipation extension pads 106 formed to extend from the first, second and third chip bonding pads 102a, 102b and 102c to the outside and escape from the leads. To the outside.

For example, the first LED chip 101a may be a red light, the second LED chip 101b may be a first green light, the third LED chip 101c may be a second green light, and a fourth LED chip ( 101d) may be configured to emit blue light. In addition, as described above, examples for configuring different colors to emit light are equally applicable here, and thus a detailed description thereof will be omitted.

FIG. 7 illustrates a light emitting diode package 70 ″ according to a second embodiment of the present invention, and includes first to fifth light emitting diode chips emitting light having different wavelengths in a row on the chip bonding pad 97. 111a, 111b, 111c, 111d, and 111e are arranged, and the first to fifth leads 113a, 113b, and 113c (both sides thereof) with the chip bonding pad 97 interposed therebetween. 113d) 113e are arranged insulated in pairs, and members shown by the same reference numerals as in Fig. 2A in Fig. 6. The same functions and functions as in Fig. 6. In the second embodiment, a chip emitting light of five different wavelengths is different. For example, the first LED chip 111a may have red light, the second LED chip 111b may have green light, and the third LED chip 111c may have blue light. The fourth LED chip 111d emits yellow light, and the fifth LED chip 111e emits cyan light.

FIG. 8 illustrates a color scheme implemented by the light emitting diode package configured as described above, and it can be seen that the color gamut is greatly extended compared to the color gamut due to R, G, and B tricolor light.

The following describes a backlight unit employing a multi-chip light emitting diode package according to the present invention.

9 schematically shows a photometric backlight unit.

The photometric backlight unit includes a light guide plate 50 for guiding light toward the display panel 80 to supply light to the display panel 80 forming an image, and a light source unit disposed on at least one surface of the light guide plate 50. 60). In addition, a diffusion sheet 72 for diffusing light emitted from the light guide plate 50 between the light guide plate 50 and the display panel 80, and a vertical prism sheet for correcting a path of light passing through the diffusion sheet 72. 74, and a horizontal prism sheet 76 is provided. The rear surface of the light guide plate 50 is provided with a reflective sheet 55 to reflect light emitted from the light guide plate 50 toward the reflective sheet 55 toward the display panel 80 to improve the light efficiency.

The display panel 80 may be, for example, a liquid crystal panel. The light source unit 60 includes a multi-chip LED package 70, 70 ′, 70 ″ arranged in a row or in a plurality of rows on the printed circuit board 65. The light source unit 60 includes a light guide plate 50. It may be disposed on one side of the surface, or on two opposite surfaces, that is, on the two opposite sides, the upper surface and the lower surface, or on the two adjacent surfaces. In order to reduce the size, the multi-chip LED package 70 is preferably arranged in a row, and the printed circuit board 65 may have a size substantially equal to the width and length of the side surface of the light guide plate 50.

The following describes a case in which the multi-chip LED package according to the present invention is employed in a direct type backlight unit. FIG. 10A illustrates a light source unit in which the package 70 ′ described above as an example of the light emitting diode package is two-dimensionally arranged on the printed circuit board 120. Instead of the package 70 ', other example packages 70 and 70 "may be used.

Referring to FIG. 10B, the light irradiated from the light emitting diode package is supplied to the image display panel 128 to form a color image. As a means for uniformly injecting light into the display panel 128 between the display panel 128 and the light source unit, a diffusion plate 122 and a diffusion sheet 124 are provided, and the diffusion sheet 124 and the display panel are provided. A prism sheet 126 is disposed between the 128 to correct the light propagation path so that the light is directed to the display panel 128. The direct type backlight unit is provided with a large number of light emitting diode packages to secure a sufficient amount of light, which is suitable for large displays.

As described above, the multi-chip LED package according to the present invention and the backlight unit employing the same package chips that emit light of at least four wavelengths different from each other, thereby widening the color gamut to implement colors closer to natural colors. It can improve color balancing. In addition, since the light is mixed in the package and light is emitted, it is possible to reduce the size and thickness of the backlight unit since there is no need for a separate space for mixing. In addition, by arranging the light emitting diode chips in a line to increase the direction angle it is possible to effectively prevent the occurrence of dark areas.

Claims (15)

A light emitting diode package in which a plurality of light emitting diode chips are packaged as a module, Chip bonding pads; Light emitting diode chips emitting light of at least four different wavelengths disposed on the chip bonding pads; Leads electrically connected to the light emitting diode chips by wire bonding; And a cavity formed on the light emitting diode chips to have a cavity, wherein the cavity is filled with a transparent material to form a light emitting window. The LED package, characterized in that the color gamut by the light emitted from the LED chip. The method of claim 1, The light emitting diode chips may include a first chip emitting red light, a second chip emitting first green light, a third chip emitting second green light in a wavelength region different from the first green light, and a fourth chip emitting blue light. Light emitting diode package comprising a. The method of claim 2, The first green light and the second green light has a wavelength difference of 5-40nm range LED package. The method of claim 1, The LED chips may include a first chip emitting a first red light, a second chip emitting a second red light in a wavelength region different from the first red light, a third chip emitting green light, and a fourth chip emitting blue light. Light emitting diode package comprising a. The method of claim 1, The LED chips include a first chip emitting red light, a second chip emitting green light, a third chip emitting blue light, a fourth chip emitting yellow light, and a fifth chip emitting cyan light. Light emitting diode package, characterized in that. The method according to any one of claims 1 to 5, The LED package is characterized in that the light emitting diode chips are arranged in a line so that the light emitted from the LED package is widely spread. The method of claim 6, The light emitting diode package of claim 1, wherein the light emitting diode package has a rectangular shape having a long length in a direction in which the light emitting diode chips are arranged in a line. The method according to any one of claims 1 to 5, And a heat dissipation extension pad which escapes the leads and extends from the chip bonding pad to the outside to release heat generated from the light emitting diode chips. A light emitting diode package in which a plurality of light emitting diode chips are packaged as a module, One chip bonding pad; First and second leads and third leads provided in pairs on both sides of the chip bonding pad; A first light emitting diode chip disposed on the chip bonding pad, the first light emitting diode chip connected to the first lead to emit red light, and a second light emitting diode chip connected to the second lead to emit first green light, the second lead A third light emitting diode chip connected to the first light emitting diode and emitting a second green light in a wavelength region different from the first green light, and a fourth light emitting diode chip connected to the third lead and emitting blue light; And a cavity formed on the light emitting diode chips to have a cavity, wherein the cavity is filled with a transparent material to form a light emitting window. The LED package, characterized in that the color gamut by the light emitted from the LED chip. A light emitting diode package in which a plurality of light emitting diode chips are packaged as a module, First, second and third chip bonding pads arranged in a line to insulate each other; First, second, and third leads disposed adjacent to the first, second, and third chipbonding pads; A first light emitting diode chip disposed on the first chip bonding pad and connected to the first lead to emit red light, and a second disposed on the second chip bonding pad and connected to the second lead to emit first green light A light emitting diode chip, a third light emitting diode chip emitting second green light in a wavelength region different from the first green light, and a fourth light emitting diode chip disposed on the third chip bonding pad and connected to a third lead to emit blue light ; And a cavity formed on the light emitting diode chips to have a cavity, wherein the cavity is filled with a transparent material to form a light emitting window. The LED package, characterized in that the color gamut by the light emitted from the LED chip. The method according to claim 9 or 10, The first green light and the second green light has a wavelength difference in the range of 5-40nm light emitting diode package. The method according to claim 9 or 10, The LED package is characterized in that the light emitting diode chips are arranged in a line so that the light emitted from the LED package is widely spread. The method of claim 12, The light emitting diode package of claim 1, wherein the light emitting diode package has a rectangular shape having a long length in a direction in which the light emitting diode chips are arranged in a line. The method according to claim 9 or 10, And a heat dissipation extension pad that escapes the first to third leads and extends outward from the chip bonding pad to dissipate heat generated from the light emitting diode chips. In the backlight unit used as a light source in a display device for forming an image, A backlight unit comprising the light emitting diode package according to any one of claims 1, 2, 3, 4, 5, 9, or 10.

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