JP5085624B2 - Light emitting diode - Google Patents

Description

The present invention relates to a light emitting diode (LED) including a light emitting diode chip (LED chip) and a nonwoven fabric carrying a phosphor, and in particular, surrounds an LED chip that emits visible light of a predetermined color with a frame member, By placing the nonwoven fabric carrying the phosphor on the frame member, the nonwoven fabric carrying the phosphor is placed above the LED chip, and visible light emitted from the LED chip and visible light emitted from the phosphor are arranged. The present invention relates to a light emitting diode that obtains visible light (hereinafter referred to as mixed color visible light).
For example, an LED chip that emits blue visible light is surrounded by a frame member, and a non-woven fabric carrying a phosphor is disposed above the LED chip by placing a non-woven fabric carrying a phosphor on the frame member. The present invention also relates to a light emitting diode that obtains white light by mixing color of blue visible light emitted from an LED chip and visible light emitted from a phosphor.

As an LED including a nonwoven fabric carrying an LED chip and a phosphor, the present applicant has previously proposed Japanese Patent Application Laid-Open No. 2006-60099. This LED has a structure in which a non-woven fabric carrying a phosphor is placed on an LED chip.
And as LED which can obtain white light while arrange | positioning the said nonwoven fabric which carry | supported the fluorescent substance above LED chip, there exists LED60 of the structure shown in FIG. 8, for example.

  That is, the LED 60 of FIG. 8 includes a substrate 62 made of an insulating material and a pair of external electrodes 64a and 64b extending from the surface of the substrate 62 to the back surface through the side surfaces. The LED chip 66 that emits blue visible light is die-bonded on the external electrode 64a, so that the external electrode 64a and one electrode (not shown) on the bottom surface of the LED chip 66 are electrically connected. Further, the other electrode (not shown) on the upper surface of the LED chip 66 is electrically connected to the other external electrode 64b through a bonding wire 68.

The LED chip 66 is surrounded by a frame member 70 provided on the substrate 62 and having a predetermined height, and is sealed with a translucent resin 72 filled in the frame member 70.
Further, by placing a peripheral portion 78a of a sheet-like nonwoven fabric 78 carrying a phosphor 76 for emitting yellow light on the frame member 70, a nonwoven fabric 78 carrying the phosphor 76 is placed above the LED chip 66. Is arranged. In this way, since the nonwoven fabric 78 is placed on the frame member 70 surrounding the LED chip 66, the nonwoven fabric 78 can be stably disposed above the LED chip 66.

As shown in FIGS. 9 to 11, the non-woven fabric 78 is formed into a sheet shape in which a large number of fibers 80 are intertwined, and a large number of voids 82 (see FIG. 11) are formed between the fibers 80. Since many fibers 80 are entangled three-dimensionally, the surface area of the fibers 80 per unit volume is extremely large.
The phosphor 76 emits light emitted from the LED chip 66 by converting the wavelength of the light into yellow visible light, and is attached to and supported on the surface of the fiber 80 constituting the nonwoven fabric 78.

  The upper end opening of the frame member 70 is closed by a translucent plate 84 made of resin or the like.

Thus, when a voltage is applied to the LED chip 66 through the pair of external electrodes 64a and 64b, the LED chip 66 emits light, and blue visible light and ultraviolet light are emitted. Further, the phosphor 76 supported on the nonwoven fabric 78 is irradiated with the light emitted from the LED chip 66, whereby yellow visible light is emitted from the phosphor 76. The blue visible light emitted from the LED chip 66 and the yellow visible light emitted from the phosphor 76 are mixed to obtain white light.
JP 2006-60099 A

  Since the LED 60 has the nonwoven fabric 78 placed on the frame member 70 surrounding the LED chip 66, as described above, the LED 60 has the advantage that the nonwoven fabric 78 can be disposed in a stable state, Since the light from the LED chip 66 is blocked by the frame member 70, the peripheral edge 78a of the nonwoven fabric 78 placed on the frame member 70 is hardly irradiated with light emitted from the LED chip 66. For this reason, the yellow visible light emitted from the phosphor 76 carried on the peripheral edge 78a of the nonwoven fabric 78 and the blue visible light emitted from the LED chip 66 are not mixed, and the phosphor 76 on the peripheral edge 78a of the nonwoven fabric 78 is not mixed. The yellow visible light radiated from was radiated to the outside as it was.

  In this case, it is conceivable that the frame member 70 is made of a transparent material or a translucent material. However, when the frame member 70 is made of a transparent material or a translucent material, the blue visible light of the LED chip 66 is transmitted to the frame member 70. Will be transmitted to the outside of the LED 60.

The present invention has been made to solve the above-mentioned problems, and its object is to surround an LED chip that emits visible light of a predetermined color with a frame member and to carry a phosphor on the frame member. By placing a non-woven fabric carrying a phosphor above the LED chip, a structure that obtains mixed color visible light of visible light emitted from the LED chip and visible light emitted from the phosphor is obtained. It is an object of the present invention to provide a light emitting diode that can prevent visible light other than mixed color visible light from being emitted outside the light emitting diode.
For example, an LED chip that emits blue visible light is surrounded by a frame member, and a non-woven fabric carrying a phosphor is disposed above the LED chip by placing a non-woven fabric carrying a phosphor on the frame member. In a light emitting diode having a structure that obtains white light by mixing blue visible light emitted from an LED chip and visible light emitted from a phosphor, visible light other than white light is emitted outside the light emitting diode. An object of the present invention is to realize a light-emitting diode that can prevent this.

In order to achieve the above object, a light-emitting diode according to claim 1 of the present invention is provided.
An LED chip that emits visible light of a predetermined color and a non-woven fabric that is impregnated with a light-transmitting binder made of a material having a refractive index larger than that of air and carries a phosphor, and is emitted from the LED chip A light-emitting diode that obtains mixed color visible light obtained by mixing color visible light and visible light emitted from the phosphor,
The LED chip is surrounded by a non-translucent first frame member, and the non-woven fabric is disposed above the LED chip by placing the peripheral edge of the non-woven fabric on the first frame member. Consisting of
Further, the inner end portion of the non-translucent second frame member surrounding the LED chip is disposed on the nonwoven fabric, and the inner end portion of the second frame member is disposed on the first frame member. Projecting inward from the tip of the inner end of the second frame member, the projecting distance L of the inner end of the second frame member,
L ≧ t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ )
[Where t is the thickness of the nonwoven fabric, n ₁ is the refractive index of the binder, and θ ₁ is the critical angle of light emitted from the binder into the air]
It is set to satisfy the formula of

The light-emitting diode according to claim 2 of the present invention is
Blue visible light emitted from the LED chip, which has a LED chip that emits blue visible light, and a non-woven fabric that is impregnated with a translucent binder made of a material having a refractive index greater than that of air and carries a phosphor. And a light emitting diode that obtains white light by color mixing with visible light emitted from the phosphor,
The LED chip is surrounded by a non-translucent first frame member, and the non-woven fabric is disposed above the LED chip by placing the peripheral edge of the non-woven fabric on the first frame member. Consists of
Further, the inner end portion of the non-translucent second frame member surrounding the LED chip is disposed on the nonwoven fabric, and the inner end portion of the second frame member is disposed on the first frame member. Projecting inward from the tip of the inner end of the second frame member, the projecting distance L of the inner end of the second frame member,
L ≧ t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ )
[Where t is the thickness of the nonwoven fabric, n ₁ is the refractive index of the binder, and θ ₁ is the critical angle of light emitted from the binder into the air]
It is set to satisfy the formula of

  A light-emitting diode according to a third aspect is the light-emitting diode according to the second aspect, wherein the first frame member and the second frame member are white.

  The light-emitting diode according to claim 4 is the light-emitting diode according to claim 1, wherein an inclined surface that expands upward is formed at an inner end portion of the second frame member. And

In the light emitting diode according to claim 1 of the present invention, the inner end portion of the second frame member is disposed on the nonwoven fabric, and the inner end portion of the second frame member is disposed on the first frame. Projecting distance L is L ≧ t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ ) [where t is the thickness of the nonwoven fabric. N ₁ is the refractive index of the binder, and θ ₁ is set to satisfy the equation of the critical angle of light emitted from the binder into the air]. Visible light that is not mixed with visible light of a predetermined color of the chip can be prevented from being emitted to the outside of the nonwoven fabric.

In the light-emitting diode according to claim 2 of the present invention, the inner end of the second frame member is disposed on the nonwoven fabric, and the inner end of the second frame member is The projecting distance L is L ≧ t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ ) [where t is a non-woven fabric. N ₁ is the refractive index of the binder, and θ ₁ is the critical angle of light emitted from the binder into the air], so that it is emitted from the phosphor at the periphery of the nonwoven fabric. The visible light which is not mixed with the blue visible light of the LED chip can be prevented from being emitted to the outside of the nonwoven fabric.

  In the light emitting diode according to claim 2, when the first frame member and the second frame member are white, absorption of white light can be prevented and the light can be efficiently reflected.

  4. The light emitting diode according to claim 1, wherein when an inclined surface that expands upward is formed at the inner end of the second frame member, the mixed color visible light (white light) is efficiently generated. It can be reflected upward.

Hereinafter, an embodiment of a light emitting diode according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, an LED 10 according to the present invention includes a substrate 12 made of an insulating material such as resin or ceramic, and a pair of external electrodes 14a and 14b extending from the surface of the substrate 12 to the back surface through side surfaces. The LED chip 16 that emits blue visible light is die-bonded on one external electrode 14a on the surface of the substrate 12, thereby connecting the external electrode 14a and one electrode (not shown) on the bottom surface of the LED chip 16 to each other. Electrically connected. Further, the other electrode (not shown) on the upper surface of the LED chip 16 is electrically connected to the other external electrode 14b through a bonding wire 18.
The LED chip 16 is made of, for example, a gallium nitride-based semiconductor crystal, and emits light that excites a phosphor described later when a voltage is applied.

  The LED chip 16 is surrounded by an annular first frame member 20 having a predetermined height and disposed on the substrate 12, and a light transmitting material made of silicon resin or the like filled in the first frame member 20. It is sealed with a conductive coating material 22. The first frame member 20 is non-translucent, and it is appropriate that the first frame member 20 be white in order to prevent white light from being absorbed and efficiently reflect the light.

  Further, the binder 32 is impregnated on the first frame member 20, more specifically, the inner end portion 20 a of the first frame member 20 located on the LED chip 16 side, and the YAG phosphor. The non-woven fabric 26 carrying the phosphor 24 is disposed above the LED chip 16 by placing the peripheral edge portion 26a of the sheet-like non-woven fabric 26 carrying the yellow light emitting phosphor 24 such as the above. By placing the nonwoven fabric 26 on the first frame member 20 surrounding the LED chip 16, the nonwoven fabric 26 can be disposed in a stable state above the LED chip 16.

As shown in FIGS. 2 to 5, the non-woven fabric 26 is formed into a sheet shape in which a large number of fibers 28 are intertwined, and a large number of voids 30 (see FIG. 4) are formed between the fibers 28. Since the fibers 28 are intertwined in three dimensions, the surface area of the fibers 28 per unit volume is extremely large.
The total surface area of the fibers 28 constituting the nonwoven fabric can be arbitrarily increased or decreased by appropriately adjusting the fiber density of the fibers 28, the thickness of the nonwoven fabric, the basis weight, and the like.

Further, the non-woven fabric 26 is impregnated with a translucent binder 32 in which the phosphor 24 is dispersed and added, so that the phosphor 24 is put on the surface of the fibers 28 constituting the non-woven fabric 26 via the binder 32. At the same time, the gap 30 between the fibers 28 is filled with a binder 32 to which a phosphor 24 is added.
As shown in FIG. 4, all the gaps 30 between the fibers 28 are filled with a binder 32.
Further, as shown in FIG. 5, the amount of the phosphor 24 deposited on the surface of the fiber 28 is larger than the amount of the phosphor 24 in the binder 32 filled in the gap 30, In the distribution state of the phosphors 24 in the binder 32 filled in the gaps 30, the amount of the phosphors 24 increases as the fiber 28 is approached.

  The translucent binder 32 is made of a material having a refractive index larger than that of air, and for example, an organic material such as silicon resin or an inorganic material such as sol-gel glass can be used.

When the phosphor 24 is irradiated with light emitted from the LED chip 16, the phosphor 24 radiates the light by converting the wavelength into yellow visible light. For example, (Y, Gd) ₃ Al ₅ O ₁₂ : A YAG phosphor such as Ce, Y ₃ Al ₅ O ₁₂ : Ce can be used.

The fibers 28 are made of resin fibers such as nylon, polyester, acrylic and polypropylene, cellulosic chemical fibers such as rayon, short fibers such as glass fibers and metal fibers, and the diameter is 5 to 20 μm and the length is 0.00. Of course, it is possible to use fibers 28 made of long fibers having a length of about 5 to 20 mm, but a length of about 50 to 100 mm.
From the viewpoint of light transmittance, it is preferable that the fiber 28 is made of a light transmissive material.

The following method can be used as an example of a method for supporting the phosphor 24 on the non-woven fabric 26.
First, a sheet-like nonwoven fabric 26 having a predetermined length is prepared, and a liquid binder 32 in which particulate phosphors 24 are dispersed and added is filled in a liquid tank (not shown).

Next, the nonwoven fabric 26 is introduced into a vacuum atmosphere in a state of being immersed in the binder 32 in the liquid tank and subjected to a deaeration treatment, whereby the air in the gap 30 between the fibers 28 and the binder 32 Is replaced.
As a result, all the gaps 30 between the fibers 28 constituting the nonwoven fabric 26 are filled with the binder 32 to which the phosphor 24 is added.
The phosphor 24 dispersed and added to the binder 32 moves in the liquid binder 32, but as a result of colliding with the solid fiber 28 and being prevented from moving, as described above, The amount of the phosphor 24 to be deposited is larger than the amount of the phosphor 24 in the binder 32 filled in the gap 30, and the distribution of the phosphor 24 in the binder 32 filled in the gap 30 is further increased. In the state, the amount of the phosphor 24 increases as the fiber 28 is approached.

Thereafter, the nonwoven fabric 26 may be heated at a predetermined temperature for a predetermined time to solidify the liquid binder 32.
For example, when the binder 32 is a silicon resin that is a thermosetting resin, the binder 32 is heated at 80 to 150 ° C. for 2 to 4 hours.
When the binder 32 is a liquid sol-gel glass material, it is heated at 80 to 120 ° C. for 0.5 to 1 hour to hydrolyze and polymerize the sol-gel glass material to form a solid sol-gel glass. To do.
The sol-gel glass is synthesized using a metal organic compound such as metal alkoxide, metal acetylacetonate, or metal carboxylate as a starting material, and its hydrolysis and polymerization reaction. It is easy to mold into glass of any shape.
The sol-gel glass material includes a metal organic compound of the general formula M (OR) n (M: metal element, R: alkyl group, n: metal oxidation number), water (for hydrolysis), methanol as a solvent, DMF ( Dimethylformamide), which can be composed of ammonia as a regulator of hydrolysis / polymerization reaction. By hydrolyzing and polymerizing this sol-gel glass material, gelation occurs, resulting in the formation of a hard glassy inorganic film. A sol-gel glass is formed.

In FIG. 1, 34 is an annular second frame member that surrounds the LED chip 16, and the second frame member 34 has an inner end 34 a on the LED chip 16 side disposed on the nonwoven fabric 26. Further, as shown in FIGS. 6 and 7, the inner end 34a of the second frame member 34 extends from the tip of the inner end 20a of the first frame member 20 to the presence of the LED chip 16. And projecting a predetermined distance L toward the inward side. As a result, the inner end portion 34a of the second frame member 34 is disposed on the peripheral edge portion 26a of the nonwoven fabric 26 and on the nonwoven fabric 26 from the peripheral edge portion 26a to the protruding distance L.
An inclined surface 34b that expands upward is formed at the inner end 34a of the second frame member 34, so that white light can be efficiently reflected upward. Further, the second frame member 34 is also non-translucent like the first frame member 20, and it is appropriate that the second frame member 34 is white in order to prevent absorption of white light and reflect it efficiently. It is.

  The LED 10 of the present invention has a non-woven fabric 26 by causing the inner end 34a of the second frame member 34 to protrude inward from the tip of the inner end 20a of the first frame member 20 by a predetermined distance L. The yellow visible light radiated from the phosphor 24 at the peripheral edge 26a is prevented from being emitted to the outside of the nonwoven fabric 26.

The protruding distance L of the inner end portion 34a of the second frame member 34 protruding from the tip of the inner end portion 20a of the first frame member 20 is set as follows.
That is, as shown in FIG. 6, the thickness of the nonwoven fabric 26 placed on the first frame member 20 is t, the refractive index of the binder 32 impregnated in the nonwoven fabric 26 is n ₁ , and the binder impregnated in the nonwoven fabric 26. When the critical angle of light emitted from the inside of the air 32 into the air is θ ₁ , the protruding distance L of the inner end portion 34a of the second frame member 34 is:
L ≧ t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ )
Set to satisfy

Here, the critical angle (θ ₁ ) is the smallest incident angle at which total reflection occurs when light traveling inside the binder 32 impregnated in the nonwoven fabric 26 has a large refractive index and travels into the air having a small refractive index. I mean. Therefore, when the incident angle is equal to or greater than the critical angle (θ ₁ ), light is reflected in the boundary surface between the binder 32 impregnated in the nonwoven fabric 26 and the air, so that the light exits into the air. Is gone.
On the other hand, when the incident angle is less than the critical angle (θ ₁ ), the light is emitted into the air, so that the protruding distance of the inner end portion 34a of the second frame member 34 satisfies the above formula. By setting L, the light emitted from the peripheral portion 26a of the nonwoven fabric 26 placed on the first frame member 20 is blocked by the second frame member 34.

For example, a case where a silicon resin having a thickness t = 0.35 mm as the nonwoven fabric 26 placed on the first frame member 20 and a refractive index n ₁ = 1.42 as the binder 32 impregnated in the nonwoven fabric 26 is used as an example. Will be described. The third decimal place is rounded off.
From the formula θ ₁ = sin ⁻¹ (1 / n ₁ ),
θ ₁ = sin ⁻¹ (1 / 1.42)
= 44.77 °
From the equation L ≧ t · tan θ ₁ ,
≧ 0.35 ・ tan44.77 °
≧ 0.35 × 0.99
≧ 0.35
As a result, the protruding distance L of the inner end portion 34a of the second frame member 34 protruding from the tip of the inner end portion 20a of the first frame member 20 is 0.35 mm or more.

Further, an example in which an acrylic resin having a thickness t = 0.35 mm as the nonwoven fabric 26 placed on the first frame member 20 and a refractive index n ₁ = 1.49 is used as the binder 32 impregnated in the nonwoven fabric 26 is used. Will be described. The third decimal place is rounded off.
From the formula θ ₁ = sin ⁻¹ (1 / n ₁ ),
θ ₁ = sin ⁻¹ (1 / 1.49)
= 42.16 °
From the equation L ≧ t · tan θ ₁ ,
≧ 0.35 · tan42.16 °
≧ 0.35 × 0.91
≧ 0.32
As a result, the protruding distance L of the inner end portion 34a of the second frame member 34 protruding from the tip of the inner end portion 20a of the first frame member 20 is 0.32 mm or more.

  In the LED 10 of the present invention, when a voltage is applied to the LED chip 16 via a pair of external electrodes 14a and 14b, the LED chip 16 emits light and emits blue visible light and ultraviolet light. Further, yellow light is emitted from the phosphor 24 by irradiating the phosphor 24 carried on the nonwoven fabric 26 with the light emitted from the LED chip 16. The blue visible light emitted from the LED chip 16 and the yellow visible light emitted from the phosphor 24 are mixed to obtain white light.

Since the peripheral edge 26a of the nonwoven fabric 26 placed on the first frame member 20 is blocked by the first frame member 20, light emitted from the LED chip 16 is hardly irradiated. The yellow visible light emitted from the phosphor 24 carried on the LED and the blue visible light emitted from the LED chip 16 are not mixed and remain yellow visible light.
Thus, in the LED 10 of the present invention, the inner end portion 34a of the second frame member 34 is disposed on the nonwoven fabric 26, and the inner end portion 34a of the second frame member 34 is disposed at the first end. Projecting inward from the tip of the inner end 20a of the frame member 20, and the projecting distance L is L ≧ t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ ) [where t Is the thickness of the nonwoven fabric 26, n ₁ is the refractive index of the binder 32, and θ ₁ is the critical angle of light emitted from the binder into the air]. It is possible to prevent the yellow visible light emitted from the phosphor 24 from being emitted to the outside of the nonwoven fabric 26.

If the protruding distance L of the inner end portion 34a of the second frame member 34 is too large, a considerable amount of white light to be radiated to the outside of the LED 10 is blocked, resulting in a decrease in luminance. In order to block yellow visible light emitted from the light source and not to block white light, the protrusion distance L is set to
L = t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ )
It can be said that the setting is most preferable.

  In the above description, the phosphor 24 for yellow light emission may be mixed into the translucent coating material 22 sealing the LED chip 16, and in this case, the luminance of the LED 10 can be improved.

In the above, the case where the non-woven fabric 26 carries the phosphor 24 for emitting yellow light has been described as an example. However, the present invention is not limited to this, and the non-woven fabric 26 has a phosphor for emitting green light. And LED for red light emission, and also applicable to LEDs that obtain white light by mixing blue visible light emitted from the LED chip 16 with green visible light and red visible light emitted from the phosphor. it can.
For example, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, SrGa ₂ S ₄ : Eu, Ca ₃ Sc can be used as the phosphor that converts the wavelength of the light emitted from the LED chip 16 into green visible light. ₂ Si ₃ O ₁₂ : Ce, α-SiAlON: Eu, β-SiAlON: Eu, and the like.
Further, as phosphors that radiate light emitted from the LED chip 16 by converting the wavelength into red visible light, for example, (Sr, Ca) S: Eu, (Ca, Sr) ₂ Si ₅ N ₈ : Eu, CaSiN ₂ : Eu, CaAlSiN ₃ : Eu, etc.

In addition, in the above, when the LED chip 16 that emits blue visible light and the light emitted from the LED chip 16 is irradiated, the phosphor 24 that converts the wavelength of the light into yellow visible light and emits the light is used. The LED 10 that obtains white light by mixing the blue visible light of the LED chip 16 and the yellow visible light of the phosphor 24 has been described as an example, but the present invention is not limited to this.
In short, the present invention is such that the LED chip 16 emits visible light of a predetermined color, and the phosphor 24 emits light of the LED chip 16 by converting the wavelength of the LED chip 16 into visible light of a predetermined color. The present invention is applicable to the light emitting diode 10 that obtains mixed color visible light obtained by mixing visible light emitted from the LED chip 16 and visible light emitted from the phosphor 24.

Thus, in the LED 10 of the present invention, as described above, the inner end 34a of the second frame member 34 is disposed on the nonwoven fabric 26, and the inner end 34a of the second frame member 34 is 1 is formed by projecting inward from the tip of the inner end portion 20a of the frame member 20, and the projecting distance L is L ≧ t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ ) [where, t is the thickness of the nonwoven fabric 26, n ₁ is the refractive index of the binder 32, and θ ₁ is the critical angle of light emitted from the binder into the air]. It is possible to prevent the visible light of the predetermined color emitted from the phosphor 24 at the peripheral edge portion 26a of the nonwoven fabric 26 that does not mix with the emitted visible light of the predetermined color from being emitted to the outside of the nonwoven fabric 26.

Note that, as described above, if the protruding distance L of the inner end portion 34a of the second frame member 34 is too large, the mixed color visible light to be radiated to the outside of the LED 10 is blocked by a considerable amount, resulting in a decrease in luminance. In order to block visible light of a predetermined color emitted from the peripheral edge portion 26a of 26 and not to block mixed color visible light, the protruding distance L is set as follows.
L = t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ )
It is most preferable to set.

When obtaining white light as mixed-colored visible light using the LED chip 16 that emits blue visible light described above and the phosphor 24 that emits the light emitted from the LED chip 16 by converting the wavelength of the light emitted from the LED chip 16 into yellow visible light. There are the following cases, for example.
First, there may be used an LED chip 16 that emits blue visible light and a red light emitting phosphor 24 that radiates light emitted from the LED chip 16 by converting the wavelength of the light into red visible light. In this case, a mixed color visible light of bluish purple to purple to reddish purple to pink is obtained according to the amount of the phosphor 24 that emits red visible light.
In addition, as the phosphor 24 for red light emission, M ₂ O ₂ S: Eu (M is any 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, (SrMg) ₃ (PO ₄ ): Sn, Y ₂ O ₃ : Eu, CaSiO ₃ : Pb, Mn, _{, (Sr, Ca) S:} Eu, (Ca, Sr) 2 Si 5 N 8: Eu, CaSiN 2: Eu, CaAlSiN 3: there is Eu and the like.

In some cases, an LED chip 16 that emits blue visible light and a green light-emitting phosphor 24 that converts the wavelength of the light emitted from the LED chip 16 into green visible light and emits it. In this case, blue-green mixed-color visible light is obtained, and the lightness and darkness changes according to the amount of phosphor.
As the phosphor 24 for green light emission, 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, SrGa ₂ S ₄ : Eu, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, α-SiAlON: Eu, β-SiAlON: Eu, and the like.

  Note that the emission color of the LED chip 16 is not limited to the above-described blue and red, but the mixed color with the emission color of the phosphor 24 excited by the emission from the LED chip 16 becomes a desired color. It can be selected as appropriate.

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

10 Light emitting diode
12 Board
14a External electrode
14b External electrode
16 LED chip
18 Bonding wire
20 First frame member
20a Inner end of first frame member
22 Translucent resin
24 phosphor
26 Nonwoven fabric
26a Non-woven fabric peripheral edge
28 fibers
30 Air gap
32 binder
34 Second frame member
34a Inner end of second frame member
34b Inclined surface
36 Translucent plate L Projection distance of inner end of second frame member protruding from tip of inner end of first frame member n ₁ Refractive index of binder t Non-woven fabric thickness θ ₁ Non-woven fabric Angle of light emitted from the binder impregnated into the air into the air

Claims (4)

An LED chip that emits visible light of a predetermined color and a non-woven fabric that is impregnated with a light-transmitting binder made of a material having a refractive index larger than that of air and carries a phosphor, and is emitted from the LED chip A light-emitting diode that obtains mixed color visible light obtained by mixing color visible light and visible light emitted from the phosphor,
The LED chip is surrounded by a non-translucent first frame member, and the non-woven fabric is disposed above the LED chip by placing the peripheral edge of the non-woven fabric on the first frame member. Consisting of
Further, the inner end portion of the non-translucent second frame member surrounding the LED chip is disposed on the nonwoven fabric, and the inner end portion of the second frame member is disposed on the first frame member. Projecting inward from the tip of the inner end of the second frame member, the projecting distance L of the inner end of the second frame member,
L ≧ t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ )
[Where t is the thickness of the nonwoven fabric, n ₁ is the refractive index of the binder, and θ ₁ is the critical angle of light emitted from the binder into the air]
A light-emitting diode, which is set to satisfy the formula: Blue visible light emitted from the LED chip, which has a LED chip that emits blue visible light, and a non-woven fabric that is impregnated with a translucent binder made of a material having a refractive index greater than that of air and carries a phosphor. And a light emitting diode that obtains white light by color mixing with visible light emitted from the phosphor,
The LED chip is surrounded by a non-translucent first frame member, and the non-woven fabric is disposed above the LED chip by placing the peripheral edge of the non-woven fabric on the first frame member. Consisting of
Further, the inner end portion of the non-translucent second frame member surrounding the LED chip is disposed on the nonwoven fabric, and the inner end portion of the second frame member is disposed on the first frame member. Projecting inward from the tip of the inner end of the second frame member, the projecting distance L of the inner end of the second frame member,
L ≧ t · tan θ ₁ , θ ₁ = sin ⁻¹ (1 / n ₁ )
[Where t is the thickness of the nonwoven fabric, n ₁ is the refractive index of the binder, and θ ₁ is the critical angle of light emitted from the binder into the air]
The light-emitting diode according to claim 1, wherein the light-emitting diode is set to satisfy the following formula.   The light emitting diode according to claim 2, wherein the first frame member and the second frame member are white.   4. The light emitting diode according to claim 1, wherein an inclined surface expanding upward is formed at an inner end portion of the second frame member. 5.

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