JP5227093B2 - Light emitting diode - Google Patents

Description

  The present invention relates to a light emitting diode chip (LED chip) and a light emitting diode (LED) provided with a nonwoven fabric carrying a wavelength converting fluorescent material that converts light emitted from the LED chip into light of a predetermined wavelength.

The applicant previously described an LED (Japanese Patent Laid-Open No. 2006-60099) in which a non-woven fabric carrying a phosphor is placed on an LED chip, or an LED (Japanese Patent Laid-Open No. 2006-60099) covered with a non-woven fabric carrying a phosphor (JP 2006-147925).
FIG. 6 shows an LED in which an LED chip is covered with a nonwoven fabric carrying a phosphor. The LED 60 is formed by connecting and fixing an LED chip 64 on a substrate 62 made of an insulating material.
A pair of external electrodes 66a and 66b extending from the front surface of the substrate 62 through the side surface to the back surface are formed in a state of being insulated from each other.

  One electrode (not shown) on the upper surface of the LED chip 64 is connected to one external electrode 66a via a bonding wire 68, and the other electrode (not shown) on the upper surface of the LED chip 64 is bonded. The wire 68 is connected to the other external electrode 66b.

The LED chip 64 and the bonding wire 68 are covered with a dome-shaped nonwoven fabric 72 that carries a phosphor 70 placed on a substrate 62.
Since the nonwoven fabric 72 is formed by entangled a large number of fibers, the surface area of the fibers per unit volume is extremely large. Further, as shown in FIG. Are formed in large numbers.
The phosphor 70 is carried on the surface of the fiber 73 constituting the nonwoven fabric 72 (FIGS. 6 and 7).

  The LED chip 64 and the non-woven fabric 72 are surrounded by a frame member 74 having a predetermined height disposed on the substrate 62, and a transparent material formed by filling the frame member 74 with a translucent material. It is sealed with a light lid member 76.

  In the light emitting diode 60, when a voltage is applied to the LED chip 64 via the pair of external electrodes 66a and 66b, the LED chip 64 emits light, and ultraviolet light, visible light, etc. that excites the phosphor 70, etc. Of light is emitted. This light is applied to the phosphor 70 carried on the dome-shaped non-woven fabric 72 covering the LED chip 64, and after wavelength conversion into light such as visible light having a predetermined wavelength, the light is transmitted through the translucent lid member 76. Is radiated to the outside.

The light emitting diode 60 covers the LED chip 64 with a dome-shaped non-woven fabric 72, and supports the phosphor 70 on the surface of the fiber 73 constituting the non-woven fabric 72. It can be taken out as reflected light reflected by the phosphor 70. For this reason, the light extraction efficiency is improved, and high brightness can be achieved. In addition, since the LED chip 64 is covered with the nonwoven fabric 72, almost all the light emitted from the LED chip 64 can be irradiated onto the nonwoven fabric 72 carrying the phosphor 70.
Further, since the light emitting diode 60 has the phosphor 70 supported on the surface of the fiber 73 constituting the nonwoven fabric 72 in which the surface area of the fiber 73 per unit volume is extremely large, the amount and surface area of the phosphor 70 are dramatically increased. It can be increased.
JP 2006-60099 A JP 2006-147925 A

  By the way, in the conventional LED 60, the phosphor 70 is bonded to the surface of the fiber 73 constituting the non-woven fabric 72 through a resin or the like, or the surface of the fiber 73 constituting the non-woven fabric 72 is melted. Since the phosphor 70 was carried on the surface of the fiber 73 by welding, the carrying of the phosphor 70 on the nonwoven fabric 70 was complicated.

  The present invention has been devised in view of the above-described conventional problems, and an object of the present invention is to provide an LED chip and a wavelength conversion phosphor that converts light emitted from the LED chip into light of a predetermined wavelength. In the light emitting diode provided with the nonwoven fabric which carries | supports this, it is providing the light emitting diode with which the fluorescent material is easy to carry | support to a nonwoven fabric.

In order to achieve the above object, a light-emitting diode according to the present invention includes:
A light emitting diode comprising a light emitting diode chip and a nonwoven fabric carrying a fluorescent material, wherein the nonwoven fabric has a fiber diameter within ± 50% of the average particle diameter of the fluorescent material, and 0.3 to 0 By forming with a fiber density of .9 g / cm ³ and a basis weight of 20 to 80 g / m ^2, a large number of voids capable of holding a fluorescent substance are formed between the fibers constituting the nonwoven fabric, and The fluorescent material is held in the voids between the fibers.

The light-emitting diode according to the present invention is a non-woven fabric in which the fiber diameter is within ± 50% of the average particle diameter of the fluorescent material, and the fiber density is 0.3 to 0.9 g / cm ³ , and 20 to 80 g / cm 2. By forming with a fabric weight of m ^2, a large number of voids capable of holding the fluorescent material are formed between the fibers constituting the nonwoven fabric, so that the fluorescent material can be applied to the voids between the fibers without bonding or welding. The fluorescent material can be easily supported on the non-woven fabric simply by being held.

Hereinafter, an embodiment of a light emitting diode according to the present invention will be described with reference to the drawings.
FIG. 1 shows a light-emitting diode 10 according to the present invention. The light-emitting diode 10 is made of an insulating material such as resin and has a substantially ring-shaped frame body 14 having holes 12 formed therein, and a first lead. A frame 16 and a second lead frame 18 are provided.
The first lead frame 16 has a front end portion 16a that covers substantially the entire bottom surface 14a of the frame body 14, and a rear end portion 16b that passes through the frame body 14 and is taken out in the horizontal direction. Yes. A part of the tip portion 16a of the first lead frame 16 is exposed in the hole 12, and the LED chip 20 is die-bonded to the tip portion 16a of the first lead frame 16 exposed in the hole 12. Thus, the first lead frame 16 and one electrode (not shown) on the bottom surface of the LED chip 20 are electrically connected.

The second lead frame 18 includes a front end portion 18a that penetrates the frame body 14 and is exposed in the hole 12, and a rear end portion 18b that is taken out in the horizontal direction toward the outside of the frame body 14. The tip 18a of the second lead frame 18 is electrically connected to the other electrode (not shown) on the upper surface of the LED chip 20 via a bonding wire 22.
When a voltage is applied, the LED chip 20 emits light such as ultraviolet light or blue visible light having a wavelength that excites a phosphor to be described later, and is made of, for example, a gallium nitride based semiconductor crystal.

The distal end portion 16a of the first lead frame 16 and the distal end portion 18a of the second lead frame 18 are insulated from each other by being arranged to face each other with a predetermined gap in the vertical direction.
In addition, the LED chip 20 is sealed by filling the hole 12 of the frame body 14 with a translucent coating material 24 made of silicon resin or the like.

  A step portion 26 is formed at the upper end of the frame body 14, and a disc-shaped non-woven fabric 30 (see FIG. 2) that carries a fine particle-like phosphor 28 is placed on the step portion 26. ing. As a result, the nonwoven fabric 30 carrying the phosphor 28 is disposed above the LED chip 20.

As shown in FIGS. 3 and 4, the nonwoven fabric 30 is formed by three-dimensionally entwining a large number of fibers 32, and a large number of voids 34 (see FIG. 4) are formed between the fibers 32. In addition, since many fibers 32 are intertwined in three dimensions, the surface area of the fibers 32 per unit volume is extremely large.
The fibers 32 are translucent and are made of cellulose-based chemical fibers such as rayon, short fibers or long fibers such as glass fibers.

As shown in FIG. 4, the phosphor 28 is held in the gap 34 between the fibers 32 constituting the nonwoven fabric 30.
That is, the fiber 32 constituting the nonwoven fabric 30 has a diameter within ± 50% of the average particle diameter of the phosphor 28.
The fiber density of the nonwoven fabric 30 composed of the fibers 32 is 0.3 to 0.9 g / cm ³ , and the basis weight is 20 to 80 g / m ² .
Thus, the non-woven fabric 30 is composed of the fibers 32 having a diameter within the range of ± 50% of the average particle diameter of the phosphor 28, and the non-woven fabric 30 has a fiber density of 0.3 to 0.9 g / cm ³ and a basis weight. 20 to 80 g / m ² , a large number of voids 34 capable of holding the phosphor 28 are formed between the fibers 32.

As described above, a large number of voids 34 capable of holding the phosphors 28 are formed between the fibers 32 constituting the nonwoven fabric 30. The phosphor 28 is held in the gap 34.
Note that the size of the gap 34 varies from a smaller one to a larger one of the phosphor 28, and a considerable amount of the sprayed phosphor 28 passes through the gap 34 larger than the phosphor 28 and the inside of the nonwoven fabric 30. Therefore, the phosphor 28 is not distributed only near the surface of the nonwoven fabric 30.
Further, the phosphor 28 can be held in the gap 34 between the fibers 32 by applying vibration to the particulate phosphor 28 and introducing the nonwoven fabric 30 into an atmosphere filled with the vibrating phosphor 28. In this case, since the vibration is given to the phosphor 28, the phosphor 28 can be spread to the inside of the nonwoven fabric 30.

The phosphor 28, when irradiated with light such as ultraviolet light or blue visible light, converts the wavelength of the light into light such as visible light having a predetermined wavelength. For example, the phosphor having the following composition can be used. .
As a phosphor 28 for red light emission that converts ultraviolet light into red visible light, M ₂ O ₂ S: Eu (M is one of La, Gd, and Y), 0.5 MgF ₂ .3.5MgO.GeO ₂ : _{Mn, 2MgO · 2LiO 2 · Sb} 2 O 3: Mn, Y (P, V) O 4: Eu, YVO 4: Eu, (Sr, Mg) 3 (PO 4): Sn, Y 2 O 3: Eu, CaSiO ₃ : Pb, Mn, etc.
Moreover, as a phosphor 28 for green light emission that converts ultraviolet light into green visible light, BaMg ₂ Al ₁₆ O ₂₇ : Eu, Mn, Zn ₂ SiO ₄ : Mn, (Ce, Tb, Mn) MgAl ₁₁ O ₁₉ , LaPO ₄ : Ce, Tb, (Ce, Tb) MgAl ₁₁ O ₁₉ , Y ₂ SiO ₅ : Ce, Tb, ZnS: Cu, Al, ZnS: Cu, Au, Al, (Zn, Cd) S: Cu, Al, SrAl ₂ O ₄ : Eu, SrAl ₂ O ₄ : Eu, Dy, Sr ₄ Al ₁₄ O ₂₅ : Eu, Dy, Y ₃ Al ₅ O ₁₂ : Tb, Y ₃ (Al, Ga) ₅ O ₁₂ : Tb, Y ₃ Al ₅ O ₁₂ : Ce, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, and the like.
Furthermore, as a phosphor 28 for blue light emission that converts ultraviolet light into blue visible light, (SrCaBa) ₅ (PO ₄ ) ₃ Cl: Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, (Sr, Mg) ₂ P ₂ O ₇ : Eu, Sr ₂ P ₂ O ₇ : Eu, Sr ₂ P ₂ O ₇ : Sn, Sr ₅ (PO ₄ ) ₃ Cl: Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, CaWO ₄ , CaWO ₄ : Pb, ZnS: Ag, Cl, ZnS: Ag, Al, (Sr, Ca, Mg) 10 (PO 4) 6 Cl 2: there is Eu and the like.
Further, when white light is obtained using the LED chip 20 that emits blue visible light, Y ₃ is used as the green light emitting phosphor 28 that converts blue visible light emitted from the LED chip 20 into green visible light. (Al, Ga) ₅ O ₁₂ : Ce, SrGa ₂ S ₄ : Eu, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, SrSiON: Eu, β-SiAlON: Eu, and the like.
Further, when the LED chip 20 that emits blue visible light is used, the phosphor 28 for red light emission that converts the blue visible light emitted from the LED chip 20 into red visible light is used as (Sr, Ca) S. : Eu, (Ca, Sr) ₂ Si ₅ N ₈ : Eu, CaSiN ₂ : Eu, CaAlSiN ₃ : Eu, and the like.
By appropriately selecting and mixing the phosphor 28 for red light emission, the phosphor 28 for green light emission, and the phosphor 28 for blue light emission, it is possible to develop various colors.
The phosphor 28 includes organic and inorganic fluorescent dyes and organic and inorganic fluorescent pigments.

  In the LED 10 of the present invention, when a voltage is applied to the LED chip 20 via the first lead frame 16 and the second lead frame 18, the LED chip 20 emits light, and the phosphor 28 is Light such as ultraviolet light or blue visible light having a wavelength to be excited is emitted. This light is applied to the phosphor 28 carried on the non-woven fabric 30 disposed above the LED chip 20, is converted into light such as visible light having a predetermined wavelength, and is then emitted to the outside.

  Thus, in the LED 10 of the present invention, since a large number of voids 34 capable of holding the phosphor 28 are formed between the fibers 32 constituting the nonwoven fabric 30, the fibers 32 can be bonded without being bonded or welded. The phosphor 28 can be easily supported on the non-woven fabric 30 only by holding the phosphor 28 in the gap 34 therebetween.

As a fluorescent material, not only the above-described phosphor 28 but also fluorescent glass, fluorescent resin, etc., when irradiated with light such as ultraviolet light or blue visible light, this light is converted into light such as visible light having a predetermined wavelength. Includes all substances to be converted.
The fluorescent glass is a transparent body formed by adding a fluorescent material to a glass material, and the fluorescent resin is a transparent body formed by adding a fluorescent material to a resin material such as an epoxy resin. These fluorescent glass and fluorescent resin may be formed into fine particles and supported on the nonwoven fabric 30 as in the case of the phosphor 28.

It is sectional drawing which shows typically the light emitting diode which concerns on this invention. It is a perspective view which shows typically the nonwoven fabric which carry | supported fluorescent substance. It is the elements on larger scale which show typically the nonwoven fabric which carry | supported fluorescent substance. It is a principal part enlarged view which shows typically the nonwoven fabric which carry | supported fluorescent substance. It is sectional drawing which shows the conventional light emitting diode typically. It is an enlarged view which shows typically the fiber which comprises the nonwoven fabric of the conventional light emitting diode. It is sectional drawing which shows typically the fiber which comprises the nonwoven fabric of the conventional light emitting diode.

10 Light emitting diode
12 holes
14 Frame
16 First lead frame
18 Second lead frame
20 LED chip
24 Coating material
28 Phosphor
30 Nonwoven fabric
32 fibers
34 Air gap

Claims (1)

A light emitting diode comprising a light emitting diode chip and a nonwoven fabric carrying a fluorescent material, wherein the nonwoven fabric has a fiber diameter within ± 50% of the average particle diameter of the fluorescent material, and 0.3 to 0 By forming with a fiber density of .9 g / cm ³ and a basis weight of 20 to 80 g / m ^2, a large number of voids capable of holding a fluorescent substance are formed between the fibers constituting the nonwoven fabric, and A light emitting diode characterized in that a fluorescent material is held in the gap between fibers.

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