JP2010258479A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To white light with high intensity and having rich color rendering properties in a light emitting device. <P>SOLUTION: A light emitting device is provided with: a blue light emitting diode (LED) 11; a green LED 12; a yellow fluorescent material 14 that absorbs blue light from the blue LED 11 as excitation light and emits yellow fluorescent light; and a red fluorescent material 15 that absorbs green light from the green LED 12 as excitation light and emits red fluorescent light. The light emitting device also is provided with: a blue and yellow light emitting section 21 that is the blue LED 11 coated with yellow sealing resin 26A in which the yellow fluorescent material 14 is dispersed and mixed; and a red and green light emitting section 22 that is the green LED 12 coated with red sealing resin 26B in which the red fluorescent material 15 is dispersed and mixed. The yellow fluorescent material 14 and the red fluorescent material 15 are respectively divided into the yellow sealing resin 26A and the red sealing resin 26B, and are disposed in close contact with each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light emitting device having excellent color rendering properties and suitable as a backlight or illumination source.

  In recent years, LED devices that obtain white light emission by combining blue LEDs (light-emitting diodes) and yellow phosphors, which are complementary colors, are commercially available as packages with a high luminous intensity price ratio. There was an inconvenience that the index of obtaining a natural color when illuminated was low. In other words, the combination of the blue LED and the yellow phosphor does not include or weakly includes both the green component and the red component, so that the color rendering property is not sufficient for a backlight of a liquid crystal display or an illumination light source. It was.

Therefore, conventionally, in order to improve color rendering properties, for example, in Patent Document 1, as shown in FIG. 7A, a green phosphor is included in a sealing resin 2 that covers the periphery of a blue LED 1. A technique has been proposed in which both the 3 and the red phosphors 4 are dispersed so that the three primary colors of light are emitted to enhance the color rendering.
Further, in Patent Document 2, as shown in FIG. 7B, each of the blue phosphor 7, the green phosphor 3, and the red phosphor 4 is dispersed in a sealing resin 6 that covers the periphery of the ultraviolet LED 5. Thus, a technique has also been proposed in which the three primary colors of light are emitted to enhance color rendering.

JP 2001-144331 A (Claims, FIG. 13) Japanese Patent Laying-Open No. 2004-127988 (Claims, FIG. 2)

The following problems remain in the conventional technology.
The color rendering property is obtained by combining the conventional single-color LEDs such as the blue LED 1 and the ultraviolet LED 5 and the phosphors 3, 4, and 7 of blue, green, and red to obtain the three primary colors of light. Although improved, the fluorescence efficiency was poor and it was difficult to obtain the required luminous intensity. That is, phosphors of multiple colors must be excited with monochromatic light of a monochromatic LED, high luminance of monochromatic light is required, and the fluorescence efficiency of each phosphor with respect to monochromatic light is different, so that sufficient luminous intensity and better Color rendering properties could not be obtained.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a light emitting device capable of obtaining white light with high luminous intensity and high color rendering properties.

  The present invention employs the following configuration in order to solve the above problems. That is, a light emitting device of the present invention includes a blue semiconductor light emitting element, a green semiconductor light emitting element, and a yellow light emitting yellow fluorescent light by absorbing blue light from the blue semiconductor light emitting element as excitation light. A phosphor, and a red phosphor that emits red fluorescence by absorbing green light from the green semiconductor light emitting element as excitation light, and a yellow sealing resin in which the yellow phosphor is dispersed and mixed A blue-yellow light emitting part coated with the blue semiconductor light emitting element, and a red green light emitting part coated with the green semiconductor light emitting element with a red sealing resin in which the red phosphor is dispersed and mixed. The yellow phosphor and the red phosphor are divided into the yellow sealing resin and the red sealing resin, respectively, and are arranged in close contact with each other.

  This light emitting device emits blue light from a blue semiconductor light emitting element, yellow light from a yellow phosphor, green light from a green semiconductor light emitting element, and red light from a red phosphor. By doing so, three primary colors of light of R (red) / G (green) / B (blue) and yellow complementary to blue can be obtained, and excellent color rendering can be obtained. Moreover, by exciting phosphors with two semiconductor light emitting elements such as LEDs, high luminous intensity can be obtained, and by adjusting the mutual light emission intensity of the two semiconductor light emitting elements, color rendering properties and color temperature can be improved. Adjustment is possible.

  In this light emitting device, in the blue yellow light emitting portion and the red green light emitting portion, the yellow phosphor and the red phosphor are dispersed and mixed in separate sealing resins, and the yellow phosphor and the red phosphor are each sealed in yellow. It is divided into a stop resin and a red sealing resin and arranged in close contact with each other, and each is excited separately by blue light of a blue semiconductor light emitting element and green light of a green semiconductor light emitting element, so that yellow is efficiently Fluorescence and red fluorescence can be obtained. Therefore, in the case where the blue and green semiconductor light emitting elements are integrally coated, the fluorescence obtained by the excitation light of each semiconductor light emitting element is blocked by the phosphors of different combinations, and the corresponding luminous intensity. However, according to the present invention, it is possible to prevent light from being shielded by other phosphors by individually coating the monochromatic excitation light and the monochromatic phosphor on a one-to-one basis.

  The light emitting device of the present invention is characterized in that an emission wavelength band of the blue semiconductor light emitting element is 470 to 490 nm, and an emission wavelength band of the green semiconductor light emitting element is 490 to 520 nm. To do.

In the light-emitting device of the present invention, the red phosphor is a CaAlSiN ₃ phosphor in which Eu is dissolved. That is, in this light emitting device, since CaAlSiN ₃ phosphor in which Eu is dissolved is used, it becomes possible to absorb green light as excitation light and emit red light fluorescence with high efficiency, thereby obtaining a stronger red component. be able to.

The present invention has the following effects.
That is, according to the light emitting device of the present invention, the blue light from the blue semiconductor light emitting element, the yellow light from the yellow phosphor using this as excitation light, and the green light from the green semiconductor light emitting element Since the red light emitted from the red phosphor with the excitation light is emitted, white light having high color intensity and excellent color rendering can be obtained, and the emission intensity of the two semiconductor light emitting elements can be adjusted. The color rendering properties and color temperature can be adjusted. In addition, the yellow phosphor and the red phosphor are divided into a yellow sealing resin and a red sealing resin, respectively, and are arranged in close contact with each other, and individually blue light and green semiconductor light emission of a blue semiconductor light emitting element. Since it is excited by the green light of the element, yellow fluorescence and red fluorescence can be efficiently obtained. Therefore, according to the illumination device using the light emitting device, white illumination with high luminance and excellent color rendering can be used as an illumination light source for a liquid crystal display using RGB color filters, a meter, an indicator, and the like. At the same time, the expressive power can be remarkably improved by adjusting the color rendering properties and the color temperature.

1 is a schematic cross-sectional view showing a light emitting device of a first reference technology according to the present invention. 1 is a schematic cross-sectional view showing a light emitting device according to an embodiment of the present invention. It is a schematic sectional drawing which shows the light-emitting device of the 2nd reference technique which concerns on this invention. It is a schematic sectional drawing which shows the light-emitting device of the 3rd reference technique which concerns on this invention. It is a schematic sectional drawing which shows the light-emitting device and illuminating device of 4th reference technique which concern on this invention. It is a schematic sectional drawing which shows the light-emitting device and illuminating device of 5th reference technique which concern on this invention. It is a schematic sectional drawing which shows the light-emitting device of the prior art example which concerns on this invention.

  Hereinafter, the first reference technique of the light emitting device according to the present invention will be described with reference to FIG.

  As shown in FIG. 1, the light emitting device 10 of the first reference technology has a blue LED (blue semiconductor light emitting element) 11, a green LED (green semiconductor light emitting element) 12, a blue LED 11 and a green LED 12 on the surface. A substrate 13 bonded and mounted with Ag paste or the like; a yellow red sealing resin 16 in which the blue LED 11 and the green LED 12 are integrally coated on the substrate 13 and the yellow phosphor 14 and the red phosphor 15 are dispersed and mixed; It has.

The blue LED 11 is a high-efficiency blue light-emitting diode element using an InGaN-based compound semiconductor having an emission wavelength band of 470 to 490 nm, for example.
The green LED 12 is a high-efficiency green light-emitting diode element using, for example, an InGaN-based or GaP-based compound semiconductor having an emission wavelength band of 490 to 520 nm.

The substrate 13 is an insulating substrate such as a substantially rectangular parallelepiped glass epoxy substrate, a BT resin substrate, a ceramic substrate, or a metal core substrate, and has a pattern of electrodes (not shown) for connection to the outside.
The electrical connection between the blue LED 11 and the green LED 12 and the substrate 13 is not shown, but the electrodes of the blue LED 11 and the green LED 12 and the connection electrodes formed on the substrate 13 are made of Ag paste. Electrical connection is established by connecting with a conductive adhesive material such as wire or a wire by wire bonding.

  The yellow phosphor 14 is a particulate phosphor material that absorbs blue light from the blue LED 11 as excitation light and emits yellow fluorescence, and is, for example, YAG (yttrium, aluminum, garnet), or delbium. Phosphors such as strontium, phosphate, silicate, and aluminate are used.

The red phosphor 15 is a particulate phosphor material that emits red fluorescence by absorbing green light from the green LED 12 as excitation light. For example, Eu2 ⁺ (europium) solid solution CaAlSiN ₃ (Calcium, aluminum, silicon trinitride) A phosphor or the like is used. Conventionally known red phosphors based on yttrium oxide, which are used in cathode ray tubes and the like, fluoresce well with electron beams and ultraviolet rays, but hardly fluoresce with visible light. However, the Eu ²⁺ solid-solution CaAlSiN ₃ phosphor is a phosphor that emits red light with high light emission intensity equivalent to that of the ultraviolet red phosphor for excitation light from blue light to green light. It is a red phosphor suitable for the reference technique.

  The yellow-red sealing resin 16 containing the yellow phosphor 14 and the red phosphor 15 is mainly made of a transparent resin such as an epoxy resin or a silicon resin. This yellow-red sealing resin 16 is molded into a substantially rectangular parallelepiped shape or a shell shape depending on the application.

  Thus, in the first reference technique, the blue light from the blue LED 11, the yellow light from the yellow phosphor 14, the green light from the green LED 12, and the red light from the red phosphor 15 are emitted. Thus, the three primary colors of RGB light and the yellow color complementary to the blue color can be obtained, and excellent color rendering can be obtained. In addition, by exciting the yellow phosphor 14 and the red phosphor 15 with the blue LED 11 and the green LED 12, respectively, high luminous intensity can be obtained efficiently, and the mutual emission intensity of the blue LED 11 and the green LED 12 can be adjusted. Thus, color rendering properties and color temperature can be adjusted.

  Next, a light emitting device according to an embodiment of the present invention will be described with reference to FIG. In the following description of the embodiment and the reference technique, the same components described in the first reference technique are denoted by the same reference numerals, and the description thereof is omitted.

  The difference between the first reference technology and an embodiment according to the present invention (hereinafter referred to as this embodiment) is that the yellow reference seal in which the yellow phosphor 14 and the red phosphor 15 are dispersed and mixed in the first reference technology. While the stop resin 16 integrally covers the blue LED 11 and the green LED 12, in the light emitting device 20 of the present embodiment, as shown in FIG. 2, a yellow sealing resin in which the yellow phosphor 14 is dispersed and mixed The blue-yellow light emitting part 21 covered with the blue LED 11 by 26A and the red-green light emitting part 22 covered with the green LED 12 by the red sealing resin 26B in which the red phosphor 15 is dispersed and mixed are provided. .

  That is, in the present embodiment, the yellow phosphor 14 and the red phosphor 15 are divided into the yellow sealing resin 26A and the red sealing resin 26B, respectively, and are arranged in close contact with each other. When the blue LED 11 and the green LED 12 are integrally covered with the yellow-red sealing resin 16 as in the first reference technique, the fluorescence obtained by the excitation light of each LED is blocked by the phosphors having different combinations. As a result, the luminous intensity is reduced accordingly. On the other hand, in the present embodiment, the yellow phosphor 14 and the red phosphor 15 are separately excited by the blue light of the blue LED 11 and the green light of the green LED 12, so that yellow fluorescence and red fluorescence are efficiently obtained. And can be prevented from being blocked by other phosphors.

  Next, second and third reference techniques according to the present invention will be described with reference to FIGS.

  The difference between the second reference technology and the present embodiment is that the blue-yellow light emitting portion 21 and the red-green light emitting portion 22 are adjacent to each other in the close contact state in the present embodiment, whereas the light emitting device 30 of the second reference technology. Then, as shown in FIG. 3, the blue-yellow light-emitting part 21 and the red-green light-emitting part 22 are adjacently arranged at a predetermined interval. That is, in the second reference technique, since the space between the adjacent blue-yellow light emitting part 21 and the red-green light emitting part 22 is spaced, the other fluorescent substance is prevented from blocking the fluorescence emitted from one fluorescent substance. can do.

  The difference between the third reference technique and the second reference technique is that, in the second reference technique, a space is provided between the blue-yellow light-emitting part 21 and the red-green light-emitting part 22 with a space therebetween. In the light emitting device 40 of the reference technology, as shown in FIG. 4, the blue-yellow light emitting part 21 and the red-green light emitting part 22 are arranged adjacent to each other via a partition wall part 41 that shields light. That is, in the third reference technique, the partition wall portion 41 is disposed between the blue-yellow light emitting portion 21 and the red-green light emitting portion 22 to divide them, thereby preventing mutual light from entering and mixing light. Therefore, light shielding by the other phosphor can be prevented. In addition, the partition part 41 is formed, for example with a plastic material, a metal material, etc. Further, if the surface of the partition wall 41 is mirror-finished or a reflective film is formed, the surface of the partition wall 41 can be made a reflective surface, and higher luminous intensity can be obtained.

  Next, the fourth and fifth reference techniques according to the present invention will be described below with reference to FIGS.

  The difference between the fourth reference technique and the second reference technique is that, in the second reference technique, the blue-yellow light emitting part 21 and the red-green light emitting part 22 are bonded on one substrate 13, whereas the fourth reference technique is different from the fourth reference technique. In the illumination device of the reference technology, as shown in FIG. 5, the blue-yellow side package 51 in which the blue-yellow light emitting portion 21 is bonded onto the blue-yellow side substrate 53 and the red-green light emitting portion 22 are on the red-green side substrate 54. The light emitting device 50 including the bonded red / green side package 52 is fixed on a mother board (circuit board) 55.

  The blue-yellow substrate 53 and the red-green substrate 54 are insulating substrates such as a substantially rectangular glass epoxy substrate, a BT resin substrate, a ceramic substrate, and a metal core substrate. (Omitted) pattern is formed. In addition, on the mother board 55, a circuit pattern (not shown) that is electrically connected to the connection electrodes of the blue-yellow side substrate 53 and the red-green side substrate 54 is formed on at least the mounting surface.

  That is, in the fourth reference technique, the light emitting device 50 including the blue-yellow side package 53 and the red-green side package 54 is mounted on the mother board 55 to constitute an illumination device. As described above, in this embodiment, since the light emitting device 50 having high luminous intensity and excellent color rendering is mounted on the mother board 55, the backlight and illumination of the liquid crystal display in various devices are produced by white light having excellent color rendering. The object can be well illuminated as a light source, and color rendering and color temperature can be adjusted during illumination.

  The difference between the fifth reference technique and the fourth reference technique is that, in the fourth reference technique, a blue-yellow light emitting part 21 having a blue-yellow light emitting part 21 bonded on a blue-yellow side substrate 53 and a red-green light emitting part 22 are provided. While the red-green side package 52 bonded on the red-green side substrate 54 is mounted on the motherboard 55, in the fifth reference technique, as shown in FIG. A plurality of light emitting devices 60 including the green light emitting unit 22 are directly bonded and fixed on a mother board (circuit board) 65. The mother board 65 has an electrode pad (not shown) and a circuit pattern (not shown) for electrical connection to the blue LED 11 and the green LED 12 via a conductive adhesive such as an Ag paste and a wire for wire bonding. Is formed.

  That is, in the fifth reference technique, a plurality of light emitting devices 60 are mounted in an array on the mother board 65, so that a light source suitable for a backlight of a liquid crystal display having a high luminance and a large area can be obtained.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above embodiment, the blue LED 11 and the green LED 12 are used as the semiconductor light emitting elements, but a blue LD (semiconductor laser) and a green LD may be applied.
The light-emitting devices 10, 20, 30, 40, 50, 60 and the illumination device using the light-emitting device include light guide plate illumination and meters for small-area liquid crystal displays such as mobile phones in addition to backlights for large-area liquid crystal displays. You may apply to various illumination light sources, such as a backlight unit of a kind or indicator.

  DESCRIPTION OF SYMBOLS 11 ... Blue LED (blue type semiconductor light emitting element) 10, 20, 30, 40, 50, 60 ... Light emitting device, 12 ... Green LED (green type semiconductor light emitting element), 14 ... Yellow fluorescent substance, 15 ... Red Phosphor, 16 ... yellow-red sealing resin, 21 ... blue-yellow light emitting part, 22 ... red-green light emitting part, 26A ... yellow sealing resin, 26B ... red sealing resin, 41 ... partition wall part, 55, 65 ... motherboard ( Circuit board)

Claims (3)

A blue semiconductor light emitting device;
A green semiconductor light emitting element;
A yellow phosphor that emits yellow fluorescence by absorbing blue light from the blue semiconductor light emitting element as excitation light;
A red phosphor that absorbs green light from the green semiconductor light emitting element as excitation light and emits red fluorescent light, and
A blue-yellow light emitting part in which the blue semiconductor light emitting element is coated with a yellow sealing resin in which the yellow phosphor is dispersed and mixed;
A red-green light emitting part in which the green semiconductor light-emitting element is coated with a red sealing resin in which the red phosphor is dispersed and mixed, and
The light emitting device, wherein the yellow phosphor and the red phosphor are divided into the yellow sealing resin and the red sealing resin, respectively, and are arranged in close contact with each other. The light-emitting device according to claim 1.
The emission wavelength band of the blue semiconductor light emitting element is 470 to 490 nm,
An emission wavelength band of the green semiconductor light emitting element is 490 to 520 nm. The light emitting device according to claim 1 or 2,
The light emitting device, wherein the red phosphor is a CaAlSiN ₃ phosphor in which Eu is dissolved.

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