JP6856981B2 - LED light emitting device - Google Patents

Description

The present invention relates to an LED light emitting device having good directivity and emission efficiency.

In recent years, LED light emitting devices using LEDs, which are characterized by power saving, high efficiency, and long life, have been rapidly becoming widespread in place of conventional light sources such as incandescent lamps and fluorescent lamps. In LED light emitting devices, improvement of emission efficiency has been a continuous issue, and directivity may be further emphasized. On the other hand, as a method for improving the directivity of the LED light emitting device and increasing the emission efficiency, a configuration in which an LED light source and an internal total internal reflection type condensing lens are combined has been proposed (for example, Patent Document 1).

Hereinafter, the prior art described in Patent Document 1 will be described with reference to the drawings.
FIG. 9 is a cross-sectional view of the LED light emitting device described in Patent Document 1. As shown in FIG. 9, in the LED light emitting device 100, the light emitting element 101 is die-bonded to the metal stem 102. The metal stem 102 covers the upper surface and the side surface of the sealing glass 105, and has a turret shape with a flat upper surface. Further, one lead 103 is integrally provided on the metal stem 102. The other lead 104 is arranged so that the upper end surface is exposed from the hole 102a provided in the metal stem 102, and the side surface is fixed by the sealing glass 105. The upper end surface of the lead 104 is connected to the electrode of the light emitting element 101 by a wire 106.

A tubular metal cap 107 is fixed to the side surface of the metal stem 102. A condenser lens 109 is arranged in a space formed by an inner surface of the metal cap 107 and an upper surface of the metal stem 102. The periphery of the upper surface 109a of the condenser lens 109 is fixed to the metal cap 107, and the lower surface of the condenser lens 109 is fixed to the upper surface of the metal stem 102.
Further, the condenser lens 109 is provided with a reflecting surface 109b (internal total internal reflection type) on the side surface thereof, and a recessed portion 109c having a concave cross section is provided at the lower portion. The upper surface of the depressed portion 109c is a downwardly convex radial curved surface 109d. The light emitting element 101 is arranged in the recessed portion 109c.

Next, the emission light characteristics of the LED light emitting device 100 will be described.
As shown in FIG. 9, among the light emitted from the light emitting element 101, the light ray Pa incident on the radial surface 109d is refracted by the radial surface 109d and heads upward.
Further, among the light emitted from the light emitting element 101, the light ray Pb directed to the side wall of the depressed portion 109b is totally reflected by the reflecting surface 109b after being refracted by this side wall and heads upward.

As described above, the LED light emitting device 100 in Patent Document 1 has a bowl-shaped overall shape of the condensing lens 109 so that the side surface is a reflective surface, and a recessed portion 109c having a concave cross section is provided at the bottom thereof. The upper surface of 109c is a radial curved surface 109d. As a result, in the LED light emitting device 100, almost all the light emitted from the light emitting element 101 goes upward.

JP-A-61-147585 (Fig. 1)

As described above, the LED light emitting device 100 described in Patent Document 1 has improved the directivity and the emission efficiency by devising the shape of the condenser lens. However, the light emitted from the light emitting element 101 is reflected at the interface between the air layer and the condenser lens 109 in the recessed portion 109c, and the LED light emitting device 100 has a problem that sufficient emission efficiency cannot be obtained. ..

(Purpose of Invention)
Therefore, the present invention is intended to solve the above problems, and an object of the present invention is to provide an LED light emitting device that improves emission efficiency while maintaining directivity.

In order to achieve the above object, the LED light emitting device in the present invention has the following configuration.
Between the incident surface and the LED light source, an incident surface at the bottom, an exit surface at the top, a condenser lens having a flange portion around the exit surface, an LED light source arranged so as to face the incident surface, and the incident surface and the LED light source. An LED light emitting device comprising a flexible flexible resin that is sandwiched between the two, has translucency, and generates a repulsive force by pressure, and a support member that houses the condensing lens and the LED light source. together with the said converging lens on the support member and the flexible resin and the LED light source stacked, there is fixed the optical system of the supporting member-fitted to the flange portion of the condenser lens, the The support member comprises a box-shaped case and a frame having a U-shaped cross section, and the light source and the flexible light source are laminated on the support member by fitting the frame to the flange portion of the case and the light source. It is characterized in that the sex resin and the LED light source are fixed by applying a necessary pressure.

According to the above configuration, in the LED light emitting device of the present invention, a flexible resin is sandwiched between the incident surface of the condenser lens and the LED light source. That is, the air layer does not intervene in the optical path from the LED light source to the condenser lens. Therefore, the reflection on the exit surface of the LED light source and the entrance surface of the condenser lens is reduced. As a result, it is possible to provide an LED light emitting device having improved emission efficiency while maintaining directivity.
Further, the condenser lens is fixed to a support member including a box-shaped case and a frame having a U-shaped cross section at a flange portion. As a result, there is nothing to block the exit surface of the condenser lens, and high luminous efficiency can be maintained. Further, the support member including the box-shaped case and the frame having a U-shaped cross section can be easily attached when the LED light emitting device is attached to another device.

The condenser lens is preferably made of a translucent resin.

The refractive index of the condenser lens is preferably larger than the refractive index of the flexible resin.

According to the above configuration, the light emitted from the LED light source, passing through the flexible resin and heading for the condenser lens is not totally reflected at the interface between the flexible resin and the condenser lens. Therefore, the loss due to reflection is reduced, and the emission efficiency is further improved.

The condenser lens is preferably an internal total reflection type lens.

According to the above configuration, the condenser lens uses an internal total reflection type lens. That is, the light obliquely incident on the condenser lens is reflected by the side surface of the condenser lens and heads upward. As a result, it is possible to provide an LED light emitting device having high directivity and emission efficiency.

It is preferable that the condensing lens includes a recess, the recess includes the incident surface, and the flexible resin is arranged in the recess.

According to the above configuration, the light that is about to leak from the side of the flexible resin to the outside is incident on the condenser lens from the side wall of the recess. Therefore, the emission efficiency can be further increased. Further, when at least a part of the LED light source is housed in the recess, the positioning of the condensing lens and the LED light source is stabilized with high accuracy, and the height of the LED light emitting device 30 can be reduced.

The support member comprises a box-shaped case and a frame having a U-shaped cross section, and the condensing lens and the condensing lens which are laminated on the support member by fitting the frame to the flange portion of the case and the condensing lens. It is preferable to apply the necessary pressure to the flexible resin and the LED light source to fix the lens .

According to the above configuration, a box-shaped case and a U-shaped cross-section frame are used as support members, and the U-shaped cross-section frame is fitted to the box-shaped case and the flange portion of the condensing lens. By applying a large amount of pressure to fix the lens, the assembling property of the LED light emitting device can be further improved.

The exit surface is preferably roughened.

According to the above configuration, the emitted light of the condenser lens is diffused. As a result, soft lighting can be performed.

The LED light source includes an LED die, a translucent resin that covers the LED die, and a reflective resin frame provided around the translucent resin, and the reflective resin frame is flexible at the top. It is good that the sex resin is arranged.

It is preferable that the flexible resin is mixed with a phosphor.

According to the configuration of the present invention, a translucent and flexible flexible resin is sandwiched between the incident surface of the condenser lens and the LED light source. That is, the air layer does not intervene in the optical path from the LED light source to the condenser lens. As a result, in the LED light emitting device of the present invention, reflection on the incident surface of the condenser lens is eliminated, and the emission efficiency is improved while the directivity is maintained.

It is a perspective view of the LED light emitting device in the 1st Embodiment of this invention. It is sectional drawing of the LED light emitting device shown in FIG. It is sectional drawing which shows the emission light characteristic of the LED light emitting device shown in FIG. It is sectional drawing of the LED light emitting device in 2nd Embodiment of this invention. It is sectional drawing which shows the emission light characteristic of the LED light emitting device shown in FIG. It is sectional drawing of the LED light emitting device in 3rd Embodiment of this invention. It is sectional drawing of the LED light emitting device in 4th Embodiment of this invention. It is sectional drawing of the LED light emitting device in 5th Embodiment of this invention. It is sectional drawing of the LED light emitting device in the prior art.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiments shown below exemplify an LED light emitting device for embodying the idea of the present invention, and the present invention is not specified in the following configuration. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments are not intended to limit the scope of the present invention to the specific description unless otherwise specified, and are merely explanatory examples. It's just that. In addition, the size, positional relationship, optical path, etc. of the members shown in each drawing may be exaggerated in order to clarify the explanation. The light emission of the LED and the excitation light of the fluorescent particles are described by typical light rays.

(First Embodiment)
Hereinafter, the LED light emitting device of the first embodiment will be described with reference to FIGS. 1 to 3.
FIG. 1 is a perspective view of the LED light emitting device 10 shown as the first embodiment of the present invention as viewed from the bottom, FIG. 2 is a cross-sectional view showing the configuration of the LED light emitting device 10, and FIG. It is a cross-sectional view. As shown in FIG. 1, the condenser lens 2 has an axis of rotational symmetry (not shown) and a flat incident surface 2a formed at the bottom. Further, the side surface of the condenser lens 2 is convex in the direction away from the axis of rotational symmetry, and the horizontal cross section becomes larger toward the upper side. A flexible resin 3 is attached to the bottom surface 2a. The LED light source 1 is in close contact with the bottom of the flexible resin 3. Note that FIG. 1 does not show a support member that holds and fixes the condenser lens 2, the LED light source 1, and the like.

Next, the configuration of the LED light emitting device 10 will be described in more detail with reference to FIG. As shown in FIG. 2, in the LED light emitting device 10, a translucent and flexible flexible resin 3 is sandwiched between the incident surface of the condenser lens 2 and the LED light source 1. The condenser lens 2 is provided with an incident surface 2a at the bottom, an exit surface 2b at the top, and a reflecting surface 2c at the side. The reflecting surface 2c is an internal total internal reflection surface, and the condenser lens 2 constitutes an internal total internal reflection lens having a bowl-shaped cross section as a whole. The condenser lens 2 may be made of a translucent resin such as acrylic, polycarbonate, or silicon.

The LED light source 1 includes a module substrate 4, an LED element 5 mounted on the module substrate 4 (hereinafter referred to as an LED die 5), a translucent resin 6 that covers the LED die 5, and a periphery of the translucent resin 6. It is provided with a reflective resin frame 7 provided in the above. A flexible resin 3 is disposed on the upper portion of the reflective resin frame 7, and the flexible resin 3 is sandwiched between the incident surface 2a of the condenser lens 2 and the upper surface of the LED light source 1.
The module substrate 4 has a wiring pattern formed on the upper surface thereof for connecting to the electrodes of the LED die 5. Further, the module substrate 4 is preferably made of a substrate material having good heat dissipation characteristics, and for example, a ceramic such as alumina or a metal plate having an insulating layer on the surface is used. Further, it is preferable that the surface has a high reflectance.

The reflective resin frame 7 is fixed to the module substrate 4 and the translucent resin 6. The translucent resin 6 filled inside the reflective resin frame 7 contains fluorescent particles and seals the LED die 5. The material constituting the reflective resin frame 7 is a white resin containing fine particles that reflect light, such as titanium oxide and alumina.
In the present embodiment, the translucent resin 6 uses a fluorescent resin mixed with yellow fluorescent particles, and a blue LED die is used as the LED die 5. With this configuration, the LED light emitting device 10 emits white light. However, the choice of phosphor and LED die is not limited to this.

Next, the characteristics and actions of the flexible resin 3, which is a feature of the present invention, will be described.
As shown in FIG. 2, the flexible resin 3 is sandwiched between the incident surface 2a of the condenser lens 2 and the translucent resin 6 of the LED light source 1. At this time, the flexible resin 3 improves the light transmission characteristic from the LED light source 1 to the incident surface 2a of the condenser lens 2 (reduces the reflection loss). That is, the flexible resin 3 is arranged between the incident surface 2a of the condenser lens 2 and the translucent resin 6 of the LED light source 1, and the incident surface 2a of the condenser lens 2 and the translucent resin 6 of the LED light source 1 are arranged. Are optically in close contact with each other.
As is well known, when light tries to enter a medium having a refractive index n1 from a medium having a refractive index n2,
R = {(n1-n2) / (n1 + n2)} ²
The reflection indicated by (R is the reflectance. Hereinafter referred to as Fresnel loss) occurs.
Since the refractive index of the translucent resin 6 contained in the condenser lens 2 and the LED light source 1 is about 1.5, if the refractive index of the flexible resin 3 is set to 1.4 to 1.6, the translucency is transmitted. The refractive indexes of the resin 6, the flexible resin 3, and the condenser lens 2 are close to each other, and the reflection loss between the condenser lens 2 and the LED light source 1 can be ignored. In particular, when the refractive index of the condenser lens 2 is made larger than the refractive index of the flexible resin 3, total reflection does not occur at the interface between the flexible resin 3 and the condenser lens 2, so that the emission efficiency is further improved.

Next, the emission light characteristics of the LED light emitting device 10 will be described with reference to FIG.
As shown in FIG. 3, among the light emitted from the LED die 5, the light rays Ps directly emitted to the incident surface 2a of the condenser lens 2 are refracted by the emitting surface 2b and emitted upward. Further, the light beam Ph heading toward the reflecting surface 2c (internal reflecting surface) after being incident from the incident surface 2a of the condenser lens 2 is reflected by the reflecting surface 2c and emitted upward.
Of the light emitted from the LED die 5, the light ray Pm directed to the side is reflected by the reflective resin frame 7, then incident from the incident surface 2a of the condenser lens 2, reflected by the reflective surface 2c, and upward. Exit.

As shown in FIG. 3, the incident surface 2a of the condenser lens 2 and the translucent resin 6 of the LED light source 1 are in close contact with each other by the flexible resin 3. Moreover, the refractive indexes of the condenser lens 2, the translucent resin 6, and the flexible resin 3 are approximated. Therefore, the reflection loss at the interface between the translucent resin 6 and the flexible resin 3 and the interface between the flexible resin 3 and the condenser lens 2 can be ignored, so that extremely good light transmission is achieved. Will be done.
As a result, in the LED light emitting device 10, the internal total internal reflection type condensing lens 2 and the LED light source 1 are brought into close contact with each other with the flexible resin 3, so that most of the light rays emitted from the LED light source 1 are substantially parallel to the upward direction. Efficiently emits as light rays.

(Second Embodiment)
Next, the LED light emitting device 20 shown as the second embodiment of the present invention will be described with reference to FIGS. 4 and 5.
FIG. 4 is a cross-sectional view of the light emitting device 20, and FIG. 5 is a cross-sectional view in which the emitted light characteristics are added to FIG. The basic configuration and operation of the LED light emitting device 20 in FIGS. 4 and 5 are the same as the configuration and operation of the LED light emitting device 10 shown in FIGS. 2 and 3, and the same element and the corresponding element are the same. Number and omit duplicate description.

The difference between the LED light emitting device 20 and the LED light emitting device 10 shown in FIG. 2 is that, as shown in FIG. 4, a recess 22d for accommodating a part of the LED light source 1 is provided at the bottom of the condensing lens 22. .. The upper surface of the recess 22d is an incident surface 22a. The recess 22d is slightly deeper than the thickness of the flexible resin 3. The flexible resin 3 is fitted into the recess 22d. In this state, the condenser lens 22 and the LED light source 1 are arranged. At this time, the flexible resin 3 is in close contact with the incident surface 22a. Further, in the LED light emitting device 20, the flexible resin 3 is a fluorescent resin in which fluorescent particles are mixed in the resin. On the other hand, the translucent resin 6 is simply composed of a transparent resin.

As described above, the LED light emitting device 20 is provided with a recess 22d at the bottom of the condenser lens 22, and the flexible resin 3 is disposed in the recess 22d. Therefore, the optical and mechanical positioning of the flexible resin 3 with respect to the condenser lens 22 is stable. In addition, the pressurization of the flexible resin 3 is stable.

Next, the emission light characteristics of the LED light emitting device 20 will be described with reference to FIG.
As shown in FIG. 5, among the light emitted from the LED die 5, the light rays Ps emitted toward the incident surface 22a of the condenser lens are refracted by the emitting surface 22b and emitted upward. Further, the light beam Ph, which is directed from the incident surface 22a of the condenser lens 2 and then directed to the reflecting surface 22c (total internal reflecting surface), is reflected by the reflecting surface 22c and emitted upward.
Further, among the light rays emitted from the LED die 5, the light rays Pm directed to the side are reflected by the reflective resin frame 7, then incident from the incident surface 22a of the condensing lens, reflected by the reflecting surface 22c, and upward. Exit.

The emission light characteristics of the light rays Ps, the light rays Ph, and the light rays Pm are almost the same as those of the LED light emitting device 10 shown in FIG. However, in the LED light emitting device 20, since the flexible resin 3 is arranged inside the recess 22d of the condensing lens 22, some of the light rays Pm toward the side are the reflective resin frame. After being reflected by 7, the light is incident on the condenser lens 22 from the side surface of the flexible resin 3 through the side wall of the recess 22d of the condenser lens 22. Further, the light beam Pm'is reflected by the total internal reflection surface of the reflection surface 22c and is emitted upward. That is, the light beam Pm'passing through the side surface of the flexible resin 3 is also effectively emitted upward. Of the light emitted by the phosphor contained in the flexible resin 3, the light passing through the side surface of the flexible resin 3 is also emitted above the condenser lens 2.

(Third Embodiment)
Next, the LED light emitting device 30 shown as the third embodiment will be described with reference to FIG.
FIG. 6 is a cross-sectional view showing the configuration of the LED light emitting device 30, and the basic configuration is the same as that of the LED light emitting device 20 shown in FIG. The difference between the LED light emitting device 30 and the LED light emitting device 20 shown in FIG. 4 is that the depth of the recess 32d provided on the bottom side of the condenser lens 32 is different as shown in FIG. It is only that the reflective resin frame 7 is not provided. Although not shown, the phosphor is contained in the translucent resin 6.
That is, while the recess 22d in the LED light emitting device 20 was deep enough to accommodate the flexible resin 3 as shown in FIG. 4, the recess 32d in the LED light emitting device 30 was deep enough to accommodate the flexible resin 3. It is formed to a depth that accommodates the entire portion of the LED light source 1 except for the module substrate 4.

As described above, the LED light source 1 is not provided with the reflective resin frame 7, and the flexible resin 3 is directly arranged on the translucent resin 6. That is, the laminate of the translucent resin 6 and the flexible resin 3 is housed in the recess 32d of the condenser lens 32.
As described above, in the LED light emitting device 30, the translucent resin 6 is a fluorescent resin, and the flexible resin 3 is a transparent resin.

The LED light emitting device 30 houses the entire portion of the LED light source 1 except the module substrate 4 in the recess 32d provided in the condenser lens 32. Therefore, even if the reflective resin frame 7 is not provided, all the light directed toward the side surface from the LED die 5 can be emitted upward through the side wall of the recess 32d. The same applies to the light emitted from the phosphor toward the side.
Further, the height of the LED light emitting device 30 can be reduced by accommodating the entire LED light source 1 in the recess 32d of the condenser lens 32. The arrangement of the phosphor is arbitrary. For example, the phosphor may be arranged only in the peripheral portion of the LED die 5 or may surround the translucent resin 6 (at this time, the flexible resin may be a fluorescent resin). May be).

(Fourth Embodiment)
Next, the LED light emitting device 40 shown as the fourth embodiment will be described with reference to FIG. 7.
FIG. 7 is a cross-sectional view of the LED light emitting device 40, and the basic configuration is the same as that of the LED light emitting device 10 shown in FIG. The difference between the LED light emitting device 40 and the LED light emitting device 10 shown in FIG. 2 is the shape of the exit surface 42b of the condenser lens 42 as shown in FIG.
That is, while the exit surface 2b of the condenser lens 2 in the LED light emitting device 10 was flat, the exit surface 42b of the condenser lens 42 in the LED light emitting device 40 was roughened by providing an uneven shape 42e. ..

The LED light emitting device 40 can perform illumination that gives a soft impression by diffusing the emitted light by roughening the emitting surface 42b of the condenser lens 42.

(Fifth Embodiment)
Next, the LED light emitting device 50 shown as the fifth embodiment will be described with reference to FIG.
FIG. 8 is a cross-sectional view of the LED light emitting device 50. The LED light emitting device 50 includes an LED light source 1, a flexible resin 3, and a condensing lens 52 housed in a support member 60. In the LED light emitting device 50, the basic configuration (hereinafter referred to as an optical system) relating to the LED light source 1, the flexible resin 3, and the condenser lens 52 is the same as that of the LED light emitting device 10 shown in FIG.
That is, the only difference between the LED light emitting device 10 and the optical system of the LED light emitting device 50 is that the LED light emitting device 50 is provided with a flange portion 52f around the upper surface of the condenser lens 52 as shown in FIG. is there. In the LED light emitting device 50, the optical system is fixed to the support member 60 by using the flange portion 52f.

The support member 60 includes a case 61 having a box-shaped cross section and a frame 62 having a U-shaped cross section. Further, in the support member 60, the frame 62 is fitted to the jaw portion 61a of the case 61 and the flange portion 52f of the condenser lens 52, and a necessary pressure is applied to fix the optical system. This pressure is generated by the repulsive force of the flexible member 3. Further, due to this pressure, the LED light source 1, the flexible resin 3, the flexible resin 3, and the incident surface 52a of the condenser lens 52 are brought into close contact with each other.

The shape of the LED light emitting device 50 is stabilized by housing the optical system in the support member 60, and the LED light emitting device 50 is easily incorporated into other devices. Further, if the support member 60 is made of a metal having good thermal conductivity, the heat generated by the LED light source 1 can be efficiently dissipated.

As described above, in the LED light emitting device of the present invention, the light transmission efficiency from the LED light source to the condensing lens can be improved by bringing the LED light source and the condensing lens into close contact with each other via the flexible resin. Further, the light transmission efficiency can be improved by approximating the refractive index of the sealing resin of the LED light source, the condensing lens, and the flexible resin.
Further, in each of the first to fifth embodiments, an internal total reflection type lens was used as the condenser lens 2 and the like. However, in providing an LED light emitting device having high directivity and emission efficiency, the condenser lens is not limited to an internal reflection type lens, and can be applied to, for example, a convex lens, a lenticular lens, and a condenser lens such as a truncated cone or a truncated cone. is there.

1 LED light source 2,22,32,42,52,109 Condensing lens
2a, 22a, 32a, 42a, 52a Incident surface 2b, 22b, 32b, 42b, 52b Exit surface 2c, 22c, 32c, 42c, 52c Reflective surface 22d, 32d Recess 42e Concavo-convex shape 52f Flange
3 Flexible resin 4 Module substrate 5 LED die 6 Translucent resin 7 Reflective resin frame 10, 20, 30, 40, 50, 100 LED light emitting device 60 Support member 61 Case 62 Frame 101 Light emitting element

Claims (8)

Between the incident surface and the LED light source, an incident surface at the bottom, an exit surface at the top, a condenser lens having a flange portion around the exit surface, an LED light source arranged so as to face the incident surface, and the incident surface and the LED light source. An LED light emitting device comprising a flexible flexible resin that is sandwiched between the two, has translucency, and generates a repulsive force by pressure, and a support member that houses the condensing lens and the LED light source. together with the said converging lens on the support member and the flexible resin and the LED light source stacked, there is fixed the optical system of the supporting member-fitted to the flange portion of the condenser lens, the The support member comprises a box-shaped case and a frame having a U-shaped cross section, and the light source and the flexible light source are laminated on the support member by fitting the frame to the flange portion of the case and the light source. An LED light emitting device characterized in that the sex resin and the LED light source are fixed by applying a necessary pressure. The LED light source includes an LED die, a translucent resin that covers the LED die, and a reflective resin frame provided around the translucent resin, and the reflective resin frame has the above-mentioned upper portion. The LED light emitting device according to claim 1 , wherein a flexible resin is arranged. The LED light emitting device according to claim 1 or 2 , wherein the condensing lens is made of a translucent resin. The LED light emitting device according to any one of claims 1 to 3 , wherein the refractive index of the condenser lens is larger than the refractive index of the flexible resin. The LED light emitting device according to any one of claims 1 to 4 , wherein the condensing lens is an internal total reflection type lens. The condensing lens includes a recess, the recess includes the incident surface, and the flexible resin is arranged in the recess, according to any one of claims 1 to 5. The LED light emitting device according to the description. The LED light emitting device according to any one of claims 1 to 6 , wherein the exit surface is roughened. The LED light emitting device according to any one of claims 1 to 7 , wherein the flexible resin is mixed with a phosphor.

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