JP2003347601A - Light emitting diode illuminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long-life light emitting diode illuminator working with a little secular change of the light pickup efficiency and a little deterioration of its light emitting diode. <P>SOLUTION: A light emitting diode 1 is face-down-mounted on a circuit board 2 and has an emitting surface on one side, not parallel to the other side. A plate-like base 3 having a thicknesswise bored through-hole 31 is mounted on the circuit board 2 in the form of housing the diode 1 in the through-hole 31 closed at one side opening with the board 2. The other opening of the through-hole 31 is closed with a synthetic resin cover 5 containing phosphor mixed thereinto; the cover 5 being apart from the diode 1. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode illuminating device using a phosphor which receives light from a light emitting diode and emits light having a wavelength different from that of the light from the light emitting diode.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 16, for example, a light emitting diode illuminating device using a phosphor which receives light from a light emitting diode and emits light having a wavelength different from that of the light emitting diode has been provided. I have. The light emitting diode lighting device includes a light emitting diode 1 and a circuit board 2 on which the light emitting diode 1 is mounted. Further, the base 3 having a plate-like shape and provided with a through hole 31 penetrating from front to back is provided in a form in which the light emitting diode 1 is housed in the through hole 31 and one opening of the through hole 31 is closed by the circuit board 2. Circuit board 2
It is attached to. On the inner peripheral surface of the through hole 31, a reflecting mirror for reflecting the light of the light emitting diode 1 is provided. Inside the through hole 31, a sealing resin 4 made of a synthetic resin containing a phosphor excited by the light of the light emitting diode 1 and emitting light having a different wavelength from the light of the light emitting diode 1 is included.
Is filled. For example, when the light emitting diode 1 is selected to emit blue light and the phosphor is selected to emit yellow light, the blue light emitted from the light emitting diode and transmitted through the sealing resin 4 and the phosphor emitted. White light is obtained by mixing with yellow light.

[0003]

However, in the above-mentioned conventional example, since the light emitting diode 1 is sealed by the sealing resin 4, the light and the light emitted from the light emitting diode 1 are sealed in the vicinity of the light emitting diode 1. The resin 4 deteriorates,
The life has been shortened due to a decrease in light extraction efficiency due to coloring of the sealing resin 4 due to deterioration or the like. Here, the light extraction efficiency is a ratio between the amount of light generated in the light emitting diode 1 and the amount of light extracted outside the light emitting diode lighting device.

The present invention has been made in view of the above circumstances, and has as its object to provide a long-life light-emitting diode illuminating device in which the light extraction efficiency is less reduced over time and the light-emitting diode is less deteriorated. It is in.

[0005]

According to a first aspect of the present invention, there is provided a light emitting diode having a plate-like shape and having an emission surface which is not parallel to another surface on one surface in a thickness direction, and wherein the light emitting diode is mounted face down. A circuit board, and a storage chamber mounted on one surface of the circuit board in a thickness direction for storing the light emitting diode, and an opening window for extracting light emitted from the light emitting diode is part of the storage chamber. A light-emitting diode, and a phosphor that converts light emitted from the light emitting diode to a different wavelength, and is attached to the base so as to be separated from the light emitting diode and cover the opening window. And a light-emitting cover.

According to a second aspect of the present invention, in the first aspect of the invention, the storage chamber is sealed by the circuit board and the cover, and a liquid that transmits light emitted by the light emitting diode is sealed in the storage chamber. It is characterized by the following.

According to a third aspect of the present invention, in the first aspect, the storage chamber is surrounded by the circuit board and the cover, and the circuit board and the cover are connected to each other so that an airflow passes through the storage chamber. A heat radiating hole for communicating the storage chamber with the outside is provided.

According to a fourth aspect of the present invention, in the first aspect of the present invention, at least one of the cover and the base is provided with attaching / detaching means for separating the cover from the opening window. And

According to a fifth aspect of the present invention, in the invention of the fourth aspect, the base is fixed to the circuit board and has a light-shielding fixed base in which the storage chamber is formed, and a surface of the fixed base. A movable base functioning as the attaching / detaching means, holding a plurality of covers having a shape corresponding to the opening windows provided on the circuit board so as to be rotatable in a plane parallel to the opening. A rotation means for rotating the movable base so that any one of the covers coincides with the position of the opening window is added.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) As shown in FIG. 1, a light-emitting diode illuminating device according to the present embodiment includes a light-emitting diode 1 mounted face-down on a circuit board 2.
The circuit board 2 includes an aluminum plate 21, an insulating film 22 covering one surface of the aluminum plate 21, and a copper circuit pattern 23 provided on the opposite side of the aluminum plate 21 with the insulating film 22 interposed therebetween.

The base 3 has a plate-like shape and is provided with a through hole 31 penetrating in the thickness direction. The cross section of the through hole 31 orthogonal to the thickness direction of the base 3 is circular, and the inner peripheral surface of the through hole 31 is an inclined surface that makes one opening wider than the other opening. In addition, a reflecting mirror is provided on the inner peripheral surface of the through hole 31. The base 3 is fixed to the circuit board 2 such that the light emitting diode 1 is housed in the through hole 31 with the surface of the through hole 31 on the side with the narrow opening facing the circuit board 2.
A plate-shaped cover 5 made of a light-transmitting synthetic resin is attached to the base 3 so as to cover the opening on the wide side of the through hole 31. That is, the opening on the wide side of the base 3 functions as an opening window. In the peripheral portion of the opening on the wide side of the through hole 31,
A cover mounting portion 33 is provided, which forms a step of reducing the thickness of the cover 5 by the thickness of the cover 5 from the other portions of the base 3, and the periphery of the cover 5 is attached to the cover mounting portion 33. It is placed. Here, the thickness dimension of the cover mounting portion 33 of the base 3 is determined by the circuit board 2 on the emission surface of the light emitting diode 1.
The cover 5 is held at a fixed position at a position apart from the light emitting diode 1 by the base 3.

A portion surrounded by the cover 5, the base 3, and the circuit board 2 is a storage room 32. The synthetic resin forming the cover 5 is kneaded with a phosphor that is excited by the light of the light emitting diode 1 and emits light having a wavelength different from that of the light of the light emitting diode 1. When the light emitting diode 1 emitting blue light and the phosphor emitting yellow light are used as a combination of the light emitting diode 1 and the phosphor, for example, white light can be obtained by mixing blue and yellow.

The shapes of the light emitting diode 1 and the circuit board 2 will be specifically described. As shown in FIG. 1, the light emitting diode 1 is formed on a plate-shaped sapphire substrate 11 and on one surface of the sapphire substrate 11. And a semiconductor layer 12 in which an InGaN n-type semiconductor layer 12a and a p-type semiconductor layer 12b are joined. The semiconductor layer 12 is provided with a bump 13, and the light emitting diode 1 is mounted face down on the circuit board 2. The surface of the sapphire substrate 11 on the side away from the semiconductor layer 12 is the emission surface. On the surface of the sapphire substrate 11 on the side remote from the semiconductor layer 12, fine irregularities are formed over the entire surface, that is, the emission surface is not parallel to the opposite side.

Here, the light generated in the semiconductor layer 12 and having reached the emission surface of the sapphire substrate 11 at an incident angle equal to or greater than the critical angle is totally reflected and reaches the semiconductor layer 12. When the surface and the semiconductor layer 12 are parallel to each other, the semiconductor layer 12 also enters the interface with air at an angle of incidence equal to or greater than the critical angle, is totally reflected, and returns to the exit surface of the sapphire substrate 11 at the same angle of incidence Incident. That is, the light that has reached the emission surface of the sapphire substrate 11 at an incident angle equal to or greater than the critical angle repeats total reflection inside the light emitting diode 1 and cannot be emitted outside the light emitting diode 1. On the other hand, since the interface between the semiconductor layer 12 and the air and the emission surface of the sapphire substrate 11 are not parallel, light totally reflected at the emission surface of the sapphire substrate 11 is reflected at the interface between the semiconductor layer 12 and the air. Then, when the light is incident on the emission surface, the incident angle changes. At this time, since some light is emitted with the incident angle smaller than the critical angle, the light extraction efficiency is improved as compared with the case where the sapphire substrate 11 and the semiconductor layer 12 are parallel.

The shape in which the exit surface and the opposite side surface are made non-parallel may be a shape in which the exit surface is inclined with respect to the opposite side surface. Alternatively, the emission surface is formed in a conical shape, the emission surface is formed in a shape that forms part of a spherical surface, or a plurality of cones or a spherical shape is formed on the emission surface, thereby forming a surface opposite to the emission surface. May be non-parallel.

According to the above configuration, the heat transmitted from the light emitting diode 1 to the cover 5 is smaller than the heat transmitted from the light emitting diode 1 to the synthetic resin when the light emitting diode 1 is sealed with the synthetic resin. Is smaller than the incident density of light received by the synthetic resin in the vicinity of the light emitting diode 1 when the light emitting diode 1 is sealed with the synthetic resin, so that the deterioration of the synthetic resin can be suppressed. Is less likely to occur, and the life is longer than in a light emitting diode lighting device in which the light emitting diode 1 is sealed with a synthetic resin.

When the light emitting diode 1 is sealed with a synthetic resin, it is necessary to use a synthetic resin having a low viscosity in order to wrap around the resin. However, since the cover 5 is plate-shaped, the cover 5 has a comparative viscosity. It can be formed using a highly synthetic resin. In addition, the cover 5 is thinner than the synthetic resin for sealing the light emitting diode 1, and the time until the synthetic resin hardens is short. Therefore, it is easy to distribute the phosphor uniformly, and it is easy to adjust the concentration of the phosphor.

The inner peripheral surface of the through hole 31 of the base 3 is an inclined surface that widens the opening of the through hole 31 in a direction away from the circuit board 2. By appropriately setting the position on the inner surface of the through hole 31 and the diameter of the cover 5, the size of the portion from which light is emitted can be freely set.

When the light emitting diode 1 is sealed with a synthetic resin, the heat of the light emitting diode 1 is mainly radiated to the outside through the circuit board 2 because the thermal conductivity of the synthetic resin is generally low. On the other hand, in the present embodiment, the air heated by the light emitting diode 1 convects inside the storage chamber 32, so that heat is easily transmitted to the cover 5 as compared with the case where the light emitting diode 1 is sealed with a synthetic resin. Since more heat is released from the cover 5, the heat dissipation is also improved. Since the heat dissipation is improved as compared with the case where the light emitting diode 1 is sealed with a synthetic resin, deterioration of the light emitting diode 1 due to heat is suppressed. Luminance can be increased by passing a current. By the way, when comparing the case where the light emitting diode 1 is sealed with a synthetic resin and the above configuration under the same conditions,
With the above configuration, it was possible to reduce the temperature of the light emitting diode 1 by about 20 ° C. as compared with the case where the light emitting diode 1 was sealed with a synthetic resin.

As shown in FIG. 2, a phosphor layer 53 coated with a phosphor may be formed on the surface of the cover 5 facing the light emitting diode 1. In this case, the phosphor is covered 5
The cover 5 may be made of glass instead of synthetic resin.

(Embodiment 2) The light-emitting diode illuminating apparatus according to the present embodiment is one in which silicon oil 9 as a liquid is sealed in a storage chamber 32 having the same configuration as that of Embodiment 1 as shown in FIG. Other configurations are the same as those of the first embodiment.

According to the above configuration, since the silicon oil 9 is sealed in the storage chamber 32, the silicon conducts heat better than air, so that the heat of the light emitting diode 1 can be more efficiently covered through the silicon oil 9. 5 to escape to the outside of the device.

(Embodiment 3) The light emitting diode illuminating device according to the present embodiment has the same structure as that of Embodiment 1,
As shown in FIG. 4, the cover 5 and the circuit board 2 are provided with heat radiating holes 51 and 24 for communicating the inside and outside of the storage chamber 32 with each other.

More specifically, as shown in FIG. 5, four heat radiation holes 51 of the cover 5 are provided at equal intervals along the circumferential direction at the peripheral edge of the cover 5. As shown in FIG. 6, the heat radiation holes 24 of the circuit board 2 are provided at positions on the circuit board 2 that sandwich the position where the light emitting diode 1 is mounted. To give an example of the dimensions, the diameter of the cover 5 is 3.2 mm, and the diameter of the heat radiation holes 51 and 24 is 0.2 mm.
2 mm, the distance H1 between the circuit board 2 and the cover 5 (see FIG. 7) is 1 mm, and the thickness dimension H2 of the circuit board 2 is 0.5 m
m, the diameter of the opening of the through hole 31 near the circuit board 2 is 1.5 mm, and the length of one side of the outer periphery of the light emitting diode 1 is 0.35 mm.

According to the above configuration, the air is radiated from the heat radiation holes 51 and 52.
4, the heat of the light emitting diode 1 can be more efficiently released to the outside of the storage room 32. For example, when the cover 5 is installed with the cover 5 facing upward, as shown by an arrow A in FIG.
Is heated by the light emitting diodes and flows out of the storage chamber 32 through the heat radiation holes 51 of the cover.

(Embodiment 4) The light-emitting diode illuminating device of this embodiment is different from that of Embodiment 1 in that the cover 5 is detachable from the base 3. More specifically, as shown in FIG. 9, the cover 5 has a circular flat plate shape,
Engaging claws 52 are protrudingly provided at the respective locations. One surface of the front and back surfaces of the engaging claw 52 is flush with one surface of the other surface of the cover 5, and the thickness of the engaging claw 52 is formed smaller than the thickness of the other portion of the cover 5. Have been. Further, as shown in FIG. 9, two engaging portions 34 that engage with the engaging claws 52 in a bayonet manner are provided at two places on the base 3 with the through hole 31 interposed therebetween. More specifically, the engaging portion 34 is provided at the base 3 near the opening window at the through hole 31.
A storage groove 34b is formed in the inner surface of the base 3 and is formed along the circumferential direction of the through-hole 31. The storage groove 34b communicates with one end of the storage groove 34b and is open to the surface of the base 3 away from the circuit board 2. And an introduction portion 34a. In each engagement portion 34, the introduction portion 34a is provided on the same side of the storage groove 34b along the circumferential direction of the through hole 31.

When the cover 5 is attached to the base 3, the side of the engaging claw 52 formed flush with the front and back surfaces of the other portions of the cover 5 is directed toward the circuit board 2, and the arrow B in FIG.
When the cover 5 is rotated relative to the base 3 as shown by the arrow C after each of the engagement claws 52 is introduced into each one of the introduction portions 34a as shown by, as shown in FIG. Each of the engaging claws 52 is housed in the housing groove 34b of each one of the engaging portions 34. When removing the cover 5 from the base,
By rotating the cover 5 in a direction opposite to the direction of attachment, each engagement claw 52 faces the introduction portion 34a of the engagement portion 34, and the cover 5 can be separated from the base 3 here. That is, the engaging claw 52 of the cover 5 and the engaging portion 34 of the base 3
Function as attachment / detachment means.

The dimensions of each part are, for example, the diameter of the cover 5 is 3.2 mm, and the distance H3 between the cover 5 and the circuit board 2 is H3.
Is 1 mm, and the thickness H4 of the circuit board 2 is 0.5 mm. The light emitting diode 1 has a square shape with an outer circumference of 0.35 mm square, and the diameter of the opening on the narrow side of the base 3 is 1.5 mm.

According to the above configuration, the light transmittance is reduced due to the deterioration of the synthetic resin constituting the cover 5, or the color of light obtained from the cover 5 due to the deterioration of the phosphor used in the cover 5 is deteriorated. The cover 5 can be easily replaced when the value changes. Also, it is easy to change the color of light by replacing the cover 5 with a cover 5 having another phosphor.

(Embodiment 5) The light emitting diode 1 according to the present embodiment emits ultraviolet light.
2 uses GaN. As shown in FIG. 12, the fixing base 8 in the present embodiment is provided with a through hole 81 which is plate-shaped and forms a storage chamber penetrating in the thickness direction, and the light emitting diode 1 is provided inside the through hole 81. Is mounted on the circuit board 2 in a form to be stored. Here, the thickness dimension of the fixed base 8 is larger than the distance of the light emitting surface of the light emitting diode 1 from the circuit board 2. The inner peripheral surface of the through hole 81 is an inclined surface that makes one opening wider than the other opening.
A reflecting mirror is formed on the inner peripheral surface of the through hole 81. The opening on the wide side of the through hole 81 functions as an opening window. Also,
As shown in FIG. 13, an output shaft 71 and a motor main body 7 for driving the output shaft 71 are provided on the side of the fixed base 8 on the circuit board 2.
2 is fixed with the output shaft 71 directed in a direction orthogonal to the circuit board 2. Further, the center of the circular plate-shaped movable base 6 is fixed to the output shaft 71 of the motor 7. The surface of the movable base 6 on the side close to the circuit board 2 is close to and opposes the surface of the fixed base 8 on the side remote from the circuit board 2. As shown in FIG. 14, four circular cover holes 61 are provided at equal intervals along the circumferential direction on one circle centered on the output shaft 71 in the movable base 6. Each cover hole 61 is provided with four covers 5 made of synthetic resin. The shape of each cover 5 matches the shape of the opening on the wide side of the through hole 81 of the fixed base 8. Each cover 5 has a different phosphor, and receives red light emitted by the light emitting diode 1 to receive red light, green light,
Emits blue and yellow light. The motor 7 is connected to the output shaft 7 so that one of the cover holes 61 overlaps the through hole 31 of the base 3 and one surface of the front and back of the cover 5 is directed to the light emitting diode 1.
1 can be rotated relative to the circuit board 2 in the direction of arrow D in FIG. Accordingly, the cover 5 is attached to and detached from the opening window as the movable base 6 rotates. That is, the motor 7 functions as a rotating unit. The movable base 6 has a diameter of, for example, 10 mm, and has a cover hole 6.
The diameter of 1 is, for example, 3 mm. The thickness H5 of the fixing base 8 is 1 mm, and the thickness H of the circuit board 2 is 1 mm.
6 is 0.5 mm.

Note that the numbers of the cover holes 61 and the covers 5 are not limited to the present embodiment, and for example, as shown in FIG.
The movable base 6 may be provided with eight cover holes 61 and eight covers 5.

According to the above configuration, the color of the light can be easily changed by changing the cover 5 for receiving the light of the light emitting diode 1 only by rotating the movable base 6 by the motor 7.

[0034]

According to the first aspect of the present invention, since the light emitting diode is not covered with a material that is deteriorated by heat or light, the life of the light emitting diode is longer than when the light emitting diode is sealed with a synthetic resin. In addition, since at least the synthetic resin for sealing the light emitting diode is not required, the cost can be reduced. Furthermore, even when the cover is made of synthetic resin and the phosphor is kneaded, less synthetic resin is used than in the case where the light emitting diode is sealed with synthetic resin, and the concentration of the phosphor is easily adjusted because the synthetic resin cures quickly. It is.

According to the second aspect of the present invention, since the liquid is sealed in the storage chamber in which the light emitting diode 1 is stored, the liquid is generally easier to conduct heat than air, so that the air is sealed in the storage chamber. Heat radiation of the light emitting diode is promoted as compared with the case.

According to the third aspect of the present invention, since the cover and the circuit board are provided with a heat radiating hole communicating between the inside and the outside of the storage chamber, at least a part of the air heated by the light emitting diode passes through the heat radiating hole. The heat exchange of the light emitting diode is promoted by the replacement.

According to the fourth aspect of the present invention, since at least one of the cover and the base is provided with attaching / detaching means capable of separating the cover from the opening window, the material of the cover and the phosphor contained in the cover deteriorate. In this case, the performance can be restored simply by replacing the cover.

According to a fifth aspect of the present invention, the base is fixed to the circuit board and has a light-shielding fixed base in which a storage chamber is formed, and the base is rotatable in a plane parallel to the surface of the fixed base. A movable base functioning as a detachable means by holding a plurality of covers supported by the circuit board and having a shape corresponding to the opening window provided in the storage chamber, and any one of the covers is positioned at the position of the opening window; Since the rotating means for rotating the movable base is added so as to match the above, the cover can be replaced only by rotating the movable base by the rotating means.

[Brief description of the drawings]

FIG. 1 is a sectional view showing Embodiment 1 of the present invention.

FIG. 2 is a sectional view showing a main part of another embodiment of the above.

FIG. 3 is a sectional view showing Embodiment 2 of the present invention.

FIG. 4 is a sectional view showing Embodiment 3 of the present invention.

FIG. 5 is a plan view showing a cover used in a third embodiment of the present invention.

FIG. 6 is a plan view illustrating a third embodiment of the present invention without including a cover.

FIG. 7 is a sectional view showing the above.

FIG. 8 is a plan view showing a cover used in a fourth embodiment of the present invention.

FIG. 9 is a plan view illustrating a fourth embodiment of the present invention without including a cover.

FIG. 10 is an explanatory diagram showing the above.

FIG. 11 is a sectional view showing the above.

FIG. 12 is a sectional view showing a main part of a fifth embodiment of the present invention.

FIG. 13 is a sectional view showing Embodiment 5 of the present invention.

FIG. 14 is a plan view showing the above.

FIG. 15 is a perspective view that does not include a base showing another embodiment of the above.

FIG. 16 is a sectional view showing a conventional example.

[Explanation of symbols] 1 Light emitting diode 2 Circuit board 24 Heat radiation holes 3 bases 32 storage rooms 5 Cover 51 Heat dissipation hole 53 phosphor layer 6 movable base 7 Motor 8 Fixed base 9 Silicone oil

   ────────────────────────────────────────────────── ─── Continuation of front page    F term (reference) 3K014 AA01 LA01 LB03                 5F041 AA33 AA44 CA02 CA34 CA40                       CA46 CB36 DA04 DA20 DA35                       DA36 DA61 DA75 EE25 FF11

Claims (5)

[Claims] 1. A light-emitting diode having a plate-like shape and having an emission surface that is non-parallel to another surface on one surface in a thickness direction, a circuit board on which the light-emitting diode is mounted face-down,
A base formed with a storage chamber mounted on one surface in the thickness direction of the circuit board for storing the light emitting diode and having an opening window for taking out light emitted from the light emitting diode formed in a part of the storage chamber And a light-transmitting cover having a phosphor that converts light emitted from the light-emitting diode to a different wavelength, and a light-transmitting cover attached to the base in a form that is separated from the light-emitting diode and covers the opening window. A light emitting diode lighting device, comprising: 2. The light-emitting diode illumination according to claim 1, wherein the storage chamber is sealed by the circuit board and the cover, and a liquid that transmits light emitted by the light-emitting diode is sealed in the storage chamber. apparatus. 3. The storage chamber is surrounded by the circuit board and the cover, and the circuit board and the cover have a radiating hole for communicating the storage chamber with the outside so that an airflow passes through the storage chamber. The light emitting diode lighting device according to claim 1, wherein the light emitting diode lighting device is provided. 4. The light-emitting diode illuminating device according to claim 1, wherein a detachable means for detaching the cover from the opening window is provided on at least one of the cover and the base. 5. A light-shielding fixed base fixed to the circuit board and having the storage chamber formed therein, and a circuit configured to be rotatable in a plane parallel to a surface of the fixed base. A movable base functioning as the attaching / detaching means, holding a plurality of covers supported by the substrate and having a shape corresponding to the opening windows provided in the storage chamber, and any one of the covers is provided with an opening window 5. A rotating means for rotating the movable base so as to match the position of the movable base is added.
The light-emitting diode lighting device according to claim 1.