JP2011192703A - Light emitting device, and illumination apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device that has excellent color rendering properties without any decrease in light emission efficiency, and to provide an illumination apparatus using the light emitting device. <P>SOLUTION: The light emitting device 1 includes a substrate 2, a blue light emitting LED element 3 and a red light emitting LED element 4 mounted on the substrate 2, a translucent first sealing member 5a which covers the blue light emitting LED element 3 and contains a phosphor, and a translucent second sealing member 5b which covers the red light emitting LED element 4. One of the first sealing member 5a and the second sealing member 5b is arranged surrounding the other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light emitting device and an illumination device that use an LED as a light source.

Recently, LEDs have been used as light sources for lighting devices. In this light source, a large number of LED bare chips are mounted on a substrate, each LED chip is electrically connected with a bonding wire, and sealed with a sealing body containing a phosphor (for example, Patent Document 1). reference). And it is going to obtain light, such as white, daylight color, and a light bulb color.
However, the light generated by these has a small reddish component, and it is difficult to obtain, for example, light bulb color light with high color rendering properties.

  For this reason, it is conceivable to provide a blue light emitting LED with a sealing body containing a yellow phosphor and a red phosphor to supplement the red component. However, the red phosphor has poor energy conversion efficiency and may cause a decrease in efficiency.

  Conventionally, an LED including a blue light emitting LED element, a red light emitting LED element, and a phosphor that is excited by the blue light emitting LED element and emits light in an emission spectrum in a wavelength band between the blue light emitting LED element and the red light emitting LED element. A lamp has been proposed (see Patent Document 2). The device disclosed in Patent Document 2 uses a red light emitting LED element, and emits red light directly from the LED element, thereby preventing the light emission efficiency from decreasing.

JP 2008-227212 A JP 2002-57376 A

  However, the one disclosed in Patent Document 2 basically has a blue light emitting LED element and a red light emitting LED element arranged on a pedestal, and both the blue light emitting LED element and the red light emitting LED element are covered with a yellow light emitting phosphor. Furthermore, these are sealed with a shell-like transparent resin.

  Therefore, the phosphor is excited when light emitted from the blue light emitting LED element collides, and emits yellow light. On the other hand, the phosphor is not excited by the light emitted from the red LED element having a long wavelength. For this reason, the light emitted from the red light emitting LED element is attenuated by colliding with the phosphor, and the light emission efficiency is lowered.

  The present invention has been made based on the above circumstances, and an object of the present invention is to provide a light-emitting device having good color rendering properties and a lighting device using the light-emitting device without reducing the light emission efficiency.

  The light-emitting device according to claim 1 includes: a substrate; a blue light-emitting LED element and a red light-emitting LED element mounted on the substrate; and a first light-transmitting light source containing a phosphor that covers the blue light-emitting LED element. A sealing member; and a translucent second sealing member that covers the red light-emitting LED element.

  The present invention aims to emit light bulb-colored light with high color rendering properties. A synthetic resin material such as a ceramic material or a glass epoxy resin can be applied to the substrate. In addition, a metal base substrate in which an insulating layer is laminated on one surface of a metal material having good thermal conductivity and excellent heat dissipation, such as aluminum, can be used.

  The blue light emitting LED element can be constituted by an LED chip that emits blue light having a wavelength of 450 nm to 470 nm, such as InGaN or GaN. The red light-emitting LED element can be constituted by an LED chip that emits red light having a wavelength of 580 nm to 620 nm, such as GaP-based or GaAlAs mixed crystal. However, these configurations are not limited to specific ones.

  The first translucent sealing member contains a phosphor. As the phosphor, for example, a yellow phosphor that is excited by light emitted from a blue light emitting LED element and emits light having a peak wavelength at a wavelength of 500 nm to 600 nm of yellow to green can be used.

  The translucent second sealing member does not contain a phosphor. Therefore, the light emitted from the red light emitting LED element that passes through the second sealing member is not attenuated by the phosphor, and the decrease in the light emission efficiency is suppressed.

  The light emitting device according to claim 2 is the light emitting device according to claim 1, wherein one of the first sealing member and the second sealing member is disposed so as to surround the other. It is characterized by.

A configuration in which the second sealing member is disposed so as to surround the first sealing member is preferable, but conversely, a configuration in which the first sealing member is disposed so as to surround the second sealing member. Is also acceptable. With this configuration, one sealing member can function as a frame member that prevents the other sealing member from flowing out and diffusing.
According to a third aspect of the present invention, there is provided an illumination device comprising: a device main body; and the light emitting device according to the first or second aspect disposed in the device main body.
The lighting device includes a light source, a lighting fixture used indoors or outdoors, a display device, and the like.

According to the first aspect of the present invention, it is possible to provide a light emitting device that can suppress a decrease in light emission efficiency and has good color rendering properties. In addition, the amount of phosphor can be reduced, which is advantageous in terms of cost.
According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the sealing member can function as a frame member.
According to invention of Claim 3, the illuminating device which produces the effect of invention of said each claim can be provided.

1 is a perspective view showing a light emitting device according to a first embodiment of the present invention. It is sectional drawing shown along XX in FIG. In a light-emitting device, it is a top view which shows the mounting state of a blue light emitting LED element and a red light emitting LED element in the state before forming a sealing member. It is a top view which shows a light-emitting device. It is sectional drawing which shows an LED lamp as an illuminating device. It is a perspective view which shows a downlight as an illuminating device. It is a top view which shows the mounting state of the blue light emitting LED element and the red light emitting LED element in the state before forming the sealing member, which shows the light emitting device according to the second embodiment of the present invention. It is a top view which shows the light-emitting device. It is a top view which shows the light-emitting device which concerns on the 3rd Embodiment of this invention, and shows the mounting state of a blue light emitting LED element and a red light emitting LED element in the state before forming a sealing member. It is a top view which shows the light-emitting device. It is a top view which shows the mounting condition of the blue light emitting LED element and the red light emitting LED element in the state before forming the sealing member, showing the light emitting device according to the fourth embodiment of the present invention. It is a top view which shows the light-emitting device.

  A light emitting device and a lighting device according to a first embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same part in each figure, and the overlapping description is abbreviate | omitted. 1 to 4 show the light emitting device 1, and FIGS. 5 and 6 show the lighting devices 20 and 30 in which the light emitting device 1 is disposed.

  As shown in FIGS. 1 and 2, the light emitting device 1 includes a substrate 2, a plurality of blue light emitting LED elements (hereinafter referred to as blue LEDs) 3 and red light emitting LED elements (hereinafter red LEDs) mounted on the substrate 2. In the drawing, it is shaded.) 4 and a sealing member 5 are provided.

  As shown in FIGS. 1 to 3, the substrate 2 includes a base material 21, a mounting pad 22 and a power supply terminal 23 provided on the front surface side of the base material 21, and a metal provided on the back surface side of the base material 21. It consists of a plate member 24. The mounting pad 22, the power supply terminal 23 and the metal plate member 24 are made of a copper plate material and are directly bonded to the base material 21.

  The base material 21 is formed in a substantially square shape with a flat plate made of a ceramic material such as white aluminum oxide, aluminum nitride, or silicon nitride, for example. As representatively shown in FIG. 3, a square mounting pad 22 on which the blue LED 3 and the red LED 4 are mounted is disposed in the center of the surface side of the base material 21. In addition, a pair of power supply terminals 23 are disposed on both sides of the mounting pad 22 at a predetermined interval.

  On the other hand, a flat metal plate member 24 is joined to the back surface side of the substrate 21 over substantially the entire surface thereof. The metal plate member 24 has a function of heat dissipation and deformation prevention of the substrate 2.

  Note that a metal base substrate in which an insulating layer is laminated on one surface of a metal material having good thermal conductivity and excellent heat dissipation, such as aluminum, as a base plate can be applied to the substrate. Further, when the base plate material is an insulating material, a synthetic resin material such as a glass epoxy resin can be applied.

  As shown in FIG. 2, the mounting pad 22 and the power supply terminal 23 have a three-layer structure, and a copper plate bonded on the surface of the base material 21 is a first layer A, and on the surface of the copper plate, The second layer B is plated with nickel (Ni), and the third layer C is plated with silver (Ag). The third layer C of the mounting pad 22, ie, the surface layer, is subjected to silver (Ag) plating, and the total light reflectance is as high as 90%.

  The blue LED 3 and the red LED 4 are LED bare chips and are directly mounted on the substrate 2. Specifically, the blue LED 3 and the red LED 4 are bonded onto the mounting pad 22 using a silicone resin insulating adhesive 6. The blue LED 3 is composed of an LED chip that emits blue light having a wavelength of 450 nm to 470 nm, such as InGaN-based or GaN-based. The blue LED 3 includes a light emitting layer that emits blue light on an element substrate such as translucent sapphire, and has a pair of positive and negative element electrodes 31 that allow current to flow through the light emitting layer. The red LED 4 is composed of an LED chip that emits red light having a wavelength of 580 nm to 620 nm, such as GaP-based or GaAlAs mixed crystal. Similarly, the red LED 4 includes a light emitting layer that emits red light on an element substrate such as translucent sapphire, and has a pair of positive and negative element electrodes 41 that allow current to flow through the light emitting layer.

  These electrodes 31 and 41 are electrically connected by a bonding wire 8. The bonding wires 8 are made of gold (Au) fine wires, and are connected via bumps mainly composed of gold (Au) in order to improve mounting strength and reduce damage to bare LED chips.

  As shown in FIG. 3, the blue LEDs 3 and the red LEDs 4 are alternately mounted in a matrix on the mounting pad 22 to form an element array of the plurality of LEDs 3 and 4. Specifically, in the element row arranged in the left-right direction in the drawing, the blue LEDs 3 and the red LEDs 4 are alternately arranged in the direction in which the row extends, and among these element rows, Three rows are connected in series, and these are connected in parallel to each other. Therefore, six series circuits are connected in parallel to each other. These are fed through a feed terminal 23.

  When attention is paid to one series circuit with reference to FIG. 2, for example, in the drawing, the blue LEDs 3 and the blue LEDs 3 are alternately arranged and arranged on the end side of the mounting pad 22. Turned and arranged in an S shape. In terms of number, there are 18 blue LEDs 3 and 15 red LEDs 4. First, the bonding wire 8 connected to the right power supply terminal 23 is connected to the positive electrode element 31 of the blue LED 3, and the other negative electrode element 31 of the blue LED 3 is connected to the adjacent red LED 4 by the bonding wire 8. The element electrode 41 on the positive electrode side is connected to the element electrode 41 on the negative electrode side of the red LED 4, and further connected to the element electrode 31 on the positive electrode side of the adjacent blue LED 3 by the bonding wire 8.

  Such connections are made sequentially, and the electrodes of the opposite polarity of the blue LED 3 and the red LED 4 adjacent in the direction in which the column extends, that is, the element electrodes 31 and 41 on the positive side of the adjacent blue LED 3 or the red LED 4 are connected. The element electrodes 41 and 31 on the negative side of the adjacent red LED 4 or blue LED 3 are connected by a bonding wire 8. The element electrode 31 on the negative side of the blue LED 3 at the tail of the column is connected to the left power supply terminal 23 by the bonding wire 8.

  On the other hand, apart from the plurality of element arrays of the blue LED 3 and the red LED 4 based on the electrical connection, the element arrays are formed in the vertical direction in the drawing, in different directions. This element row has a form in which the rows of blue LEDs 3 and the rows of red LEDs 4 are alternately arranged in units of rows. Specifically, the blue LED 3 rows and the red LED 4 rows are alternately arranged in sequence, the blue LED 3 rows are 6 rows, the red LED 4 rows are 5 rows, and a total of 11 element rows are formed. Yes.

  As shown in FIGS. 1, 2, and 4, the mounting region of the blue LED 3 and the red LED 4 is sealed by a sealing member 5. The sealing member 5 is made of a translucent synthetic resin, for example, a transparent silicone resin, and includes a first sealing member 5a containing a phosphor and a second sealing member 5b containing no phosphor. It consists of types.

  The first sealing member 5 a is disposed corresponding to the blue LED 3, that is, corresponding to the vertical element row of the blue LED 3, and covers the blue LED 3. Therefore, six rows of blue LEDs 3 are covered with the first sealing member 5a.

  The second sealing member 5 b is disposed corresponding to the red LED 4, that is, corresponding to the vertical element row of the red LED 4, and covers the red LED 4. Accordingly, the five rows of red LEDs 4 are covered by the second sealing member 5b. In addition, the second sealing member 5b covers the portion of the power supply terminal 23 to which the bonding wire 8 is connected, and has a rectangular shape as a whole, except for the region where the blue LED 3 is mounted. 2 is formed. For this reason, the 2nd sealing member 5b surrounds the 1st sealing member 5a.

  The phosphor mixed in the first sealing member 5a is excited by the light emitted from the blue LED 3, and emits light of a color different from the color of the light emitted from the blue LED 3. In order to be able to convert the blue light emitted by the blue LED 3 into white light, the phosphor emits light having a peak wavelength at a wavelength of 500 nm to 600 nm of yellow to green, which is complementary to the blue light. A yellow phosphor is used.

  The sealing member 5 is applied on the substrate 2 in an uncured state. For example, the second sealing member 5b is adjusted to have a relatively high viscosity. Therefore, first, the second sealing member 5b including the element array of the red LED 4 is applied except for the region where the blue LED 3 is mounted. Thereafter, the first sealing member 5a is applied or injected corresponding to the element row of the blue LED 3 to which the second sealing member 5b is not applied. In this case, the second sealing member 5b functions as a frame member that prevents the first sealing member 5a from flowing out even when the viscosity of the first sealing member 5a is low. It has become. Next, the sealing member 5 is formed by heat curing.

  Therefore, the provision of the frame member is not hindered, but the frame member can be omitted, and there is no need to provide a special frame member. In addition, the formation method of the said sealing member 5 is only an example, and is not limited to this.

  When power is supplied to the light emitting device 1 having the above configuration through the power supply terminal 23, each blue LED 3 and red LED 4 emits light. The blue light emitted from the blue LED 3 excites the yellow phosphor contained in the first sealing member 5a5, and is converted from yellow phosphor to yellow to green fluorescence to be the first sealing member. The light passes through 5a and is radiated to the outside. Further, of the blue light emitted from the blue LED 3, the light that has not excited the yellow phosphor passes through the first sealing member 5 a as it is and is emitted to the outside. Further, the red light emitted from the red LED 4 is transmitted to the outside through the second sealing member 5b. In this case, since the phosphor is not mixed in the second sealing member 5b, the red light emitted from the red LED 4 is emitted to the outside without being attenuated by the phosphor.

  Further, the mounting pad 22 functions as a heat spreader that diffuses the heat generated by the LEDs 3 and 4 during the light emission of the blue LEDs 3 and the red LEDs 4. Further, the light emitted from the LEDs 3 and 4 toward the substrate 2 is reflected by the surface layer of the mounting pad 22 mainly in the light utilization direction.

  Therefore, blue light from the blue LED 3, yellow to green light from the yellow phosphor, and red light from the red LED 4 are mixed from the light emitting device 1, and light bulb color light with good color rendering is emitted. In this case, since red light is directly emitted from the red LED 4, the red component can be mixed efficiently and the color rendering is improved.

As described above, according to the present embodiment, it is possible to provide the light emitting device 1 having good color rendering properties without reducing the light emission efficiency. Further, since the phosphor is provided corresponding to the blue LED 3, the amount of the phosphor can be reduced, which is advantageous in terms of cost. Furthermore, since the 1st sealing member 5a and the 2nd sealing member 5b can be arrange | positioned along the element row | line | column of the blue light emitting LED element 3, and the element row | line | column of the red light emitting LED element 4, formation of the sealing member 5 is possible. The process can be simplified. Furthermore, since the second sealing member 5b surrounds the first sealing member 5a, it serves as a frame member that prevents the first sealing member 5a from flowing out or diffusing. It is possible to fulfill the functions of
Next, an example in which the light emitting device 1 is applied to a lighting device will be described with reference to FIGS.
Example 1

  In FIG. 5, a light bulb-shaped LED lamp 20 is shown as an illumination device. The LED lamp 20 includes a light emitting device 1, a main body 20a that is thermally coupled to the light emitting device 1, a lighting circuit 20b that controls lighting of the light emitting device 1, a cover member 20c that houses the lighting circuit 20b, and a cover member 20c. The globe 20e is attached to the main body 20a so as to cover the attached base 20d and the light emitting device 1.

The main body 20a is made of, for example, a metal material such as aluminum having good thermal conductivity, and has a substantially cylindrical shape whose diameter is gradually increased from one end side to the other end side, and a plurality of heat radiation fins are integrated on the outer peripheral surface. Is formed.

The lighting circuit 20b is configured by mounting circuit components on a rectangular flat lighting circuit board. Circuit components such as a transistor Q, a resistance element R, a constant voltage diode ZD, a full-wave rectifier REC, and a capacitor C are mounted on the lighting circuit board over both surfaces. Further, the lighting circuit board is vertically arranged in the longitudinal direction, and is housed in a cover member 20c formed of an insulating material such as PBT resin. In addition, the light-emitting device 1 and the lighting circuit 20b are electrically connected by the lead wire which penetrates the wiring hole which is not shown in figure.
According to the present embodiment, by supplying power to the light emitting device 1 through the lighting circuit 20b, it is possible to efficiently transmit the desired light color through the globe 20e.
(Example 2)

  FIG. 6 shows a downlight 30 that is used as a lighting device embedded in a ceiling. The downlight 1 includes a light-emitting device 1, a main body 30a in which the light-emitting device 1 is accommodated, a light distribution member 30b attached to the main body 30a, and a light-transmitting cover 30c disposed in front of the light-emitting device 1. A power supply unit (not shown) that supplies power to the light emitting device 1 is provided. An attachment leaf spring 30d is mounted on the outer peripheral side of the main body 30a.

  The main body 30a is formed of a material having good thermal conductivity, for example, an aluminum alloy die casting. A plurality of radiating fins extending in the vertical direction are formed on the outer surface of the main body 30a.

  According to such a configuration, as in the first embodiment, by supplying power to the light emitting device 1 through the power supply unit, it is possible to efficiently emit the desired light color transmitted through the cover 30c and controlled by the light distribution member 30b. Can get well.

  Next, a light emitting device according to a second embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part which is the same as that of 1st Embodiment, or an equivalent part, and the overlapping description is abbreviate | omitted.

  In the present embodiment, in the individual arrangement of the blue LEDs 3, the arrangement of the element electrodes 31 is arranged so as to be in the direction of the element rows of the blue LEDs 3 (up and down in the drawing). The blue LED 3 columns and the red LED 4 columns are alternately arranged in units of columns, the blue LED 3 has five element columns, and the red LED 4 has four element columns.

  According to the present embodiment, the same effects as the first embodiment can be obtained. Also, with this configuration, the width dimension for forming the first sealing member 5a can be reduced, and the amount of phosphor can be further reduced.

Next, a light emitting device according to a third embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part which is the same as that of 1st Embodiment, or an equivalent part, and the overlapping description is abbreviate | omitted.
In the present embodiment, the red LED 4 is arranged on the power supply terminal 23 side. That is, it is mounted on both sides of the mounting pad 22.

  As shown in FIG. 9, the blue LED 3 and the red LED 4 are arranged on the mounting pad 22, and five series circuits are connected in parallel to each other. When one series circuit is taken, first, in the drawing, the bonding wire 8 connected to the right power supply terminal 23 is connected to the element electrode 41 on the positive side of the red LED 4, and further on the negative side of the red LED 4. The element electrode 41 is connected to the element electrode 41 on the positive electrode side of the adjacent red LED 4 by the bonding wire 8, and then the element electrode 41 on the negative electrode side of the red LED 4 is connected to the element electrode on the positive electrode side of the blue LED 3 by the bonding wire 8. 31 is connected. Thereafter, the element electrodes 31 of the blue LEDs 3 are sequentially connected by the bonding wires 8, connected to the two left red LEDs 4, and connected to the left power supply terminal 23.

  On the other hand, in the drawing, a row of blue LEDs 3 and a row of red LEDs 4 are formed in the vertical direction. Two rows on both sides are the element rows of the red LED 4, and six rows in the center are the element rows of the blue LED 3.

  As shown in FIG. 10, the first sealing member 5a covers each blue LED 3 mounted in a concentrated manner at the center. The second sealing member 5b covers the power supply terminal 23 to which the element array of the red LED 4 and the bonding wire 8 are connected so as to surround the first sealing member 5a. Yes.

  According to the present embodiment, in addition to the effects of the first embodiment, the formation region of the sealing member 5 is reduced in number, that is, two places, so that the formation process can be simplified. Furthermore, although the red LED 4 has a characteristic that the characteristic changes greatly with a temperature change, the influence of the change in the characteristic can be reduced. That is, when a plurality of blue LEDs 3 and red LEDs 4 are mounted on the substrate 2, the temperature of the central portion of the substrate 2 tends to increase, and the temperature change tends to increase. Therefore, by not arranging the red LED 4 on the end side of the substrate 2, that is, in the central portion, the degree of temperature change can be reduced.

  Next, a light emitting device according to a fourth embodiment of the invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part which is the same as that of 1st Embodiment, or an equivalent part, and the overlapping description is abbreviate | omitted.

In the present embodiment, the substrate 2 is formed in a circular shape, in which one red LED 4 is arranged at the center of a substantially octagonal mounting pad 22 and four blue LEDs 3 are arranged around it. is there. The second sealing member 5b covers the red LED 4 at the center, and the first sealing member 5a covers the blue LED 3. Therefore, the 1st sealing member 5a containing a fluorescent substance is arrange | positioned so that the 2nd sealing member 5b may be surrounded.
According to this embodiment, the same effect as that of the first embodiment can be obtained.

  The present invention is not limited to the configuration of each of the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, the second sealing member may be disposed so as to surround the first sealing member containing the phosphor, and conversely, the first sealing member is the second sealing member. The case where it arrange | positions so that a member may be surrounded may be sufficient.

Moreover, in the said embodiment, although demonstrated about what connected the electrode of the different polarity of LED adjacent to the direction where the row | line | column extends in a LED element row | line | column sequentially by a bonding wire, You may make it connect via the wiring pattern formed in the board | substrate.
In addition, the lighting device can be applied to a light source, a lighting fixture used indoors or outdoors, a display device, and the like.

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device, 2 ... Board | substrate, 3 ... Blue light emission LED element,
4 ... red light emitting LED element, 5 ... sealing member, 5a ... 1st sealing member,
5b ... second sealing member,
20, 30 ... Lighting device (LED lamp, downlight),
20a, 30a ... Device main body (LED lamp main body, downlight main body)

Claims (3)

A substrate;
A blue light emitting LED element and a red light emitting LED element mounted on the substrate;
A translucent first sealing member containing a phosphor covering the blue light emitting LED element;
A translucent second sealing member covering the red light emitting LED element;
A light-emitting device comprising:   2. The light emitting device according to claim 1, wherein one of the first sealing member and the second sealing member is disposed so as to surround the other. The device body;
The light-emitting device according to claim 2 or 2, which is disposed in the device main body;
An illumination device comprising:

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