JP2014241313A - LED device - Google Patents

Abstract

Provided is an LED device capable of correcting a luminescent color even with a structure obtained by a simple additional process. An LED device includes an LED die that is flip-chip mounted on a submount substrate, and a sealing resin that covers the periphery of the LED die and the upper surface of the submount substrate. The sealing resin 15 contains a phosphor, and a diffusion layer 14 is present on the top thereof. The diffusion layer 14 is formed by implanting a diffusion material by a sandblast method. The light emission color of the LED device 10 is adjusted based on the diffusion degree of the diffusion layer 14. [Selection] Figure 1

Description

  The present invention relates to an LED device in which an LED die is covered with a light-transmitting sealing resin, and more particularly to an LED device that can easily correct an emission color by scattering of the sealing resin.

  An LED device in which an LED die cut out from a wafer is mounted on a lead frame or a circuit board and covered with a light-transmitting member such as resin or glass has become widespread.

  In this LED device, the emission color is determined by the emission spectrum of the LED die, the sealing resin containing the phosphor, the reflection characteristics of the substrate for mounting the LED die, and the like. However, since these conditions are not always constant, the emission color varies for each LED device. Therefore, it has been required to correct the emission color of each LED device so that the emission color of the LED device falls within a certain range.

  Under such circumstances, as a method for correcting the emission color to the yellow side (long wavelength side), a method using scattering on the upper surface of the sealing resin included in the LED device is known. Then, FIG. 3 of patent document 1 is re-displayed in FIG. 4, and the correction | amendment of the structure of this LED device and luminescent color is demonstrated. FIG. 4 is a cross-sectional view of the light emitting element 100a (LED device). In the figure, some symbols are changed. In FIG. 4, a light emitting diode chip 108 (LED die) is mounted on a substrate included in the light emitting element 100 a, and the sealing resin portion 105 covers the light emitting diode chip 108. The sealing resin portion 105 contains a phosphor 110 and includes a light scattering resin portion 106a on the top.

  A part of the light emitted from the light emitting diode chip 108 is scattered by the light scattering resin portion 106a as indicated by an arrow in the figure, and the light returning to the sealing resin portion 105 is wavelength-converted by the phosphor 110. . That is, the light emission color of the light emitting element 100a is corrected by the light scattering resin portion 106a. For example, when a blue light emitting diode chip and a yellow phosphor are used, part of the blue light emitted from the light emitting diode chip 108 is scattered by the light scattering resin portion 106 a and returns to the sealing resin portion 105. The blue light returning to the sealing resin portion 105 excites the phosphor 110 and is converted into yellow light. As a result, in the light emitted from the light emitting diode chip 108, the blue light component decreases and the yellow light component increases. If the application amount of the light scattering resin portion 106a is adjusted using this principle, the emission color of the light emitting element 100a can be adjusted.

  Patent Document 2 describes in paragraph 0026 that “the light scattering portion is provided in a region within a critical angle to adjust the chromaticity of pseudo white light emitted from the LED light source to be yellow”. Here, the LED light source 100 of Patent Document 2 means an LED device. FIG. 1 of Patent Document 2 shows ten light scattering portions 107 formed on the upper surface of the sealing member 106 by cutting with a drill. The LED light source 100 adjusts the emission color according to the number of light scattering portions 107.

JP 2009-130301 A (FIG. 3) JP 2009-283877 A (paragraph 0026, FIG. 1)

  The LED device (light emitting diode chip 108) disclosed in Patent Document 1 forms a scattering portion (light scattering resin portion 106a) on an upper surface of a sealing resin (sealing resin portion 105) by an additional process such as coating. It was. Further, in the LED device (LED light source 100) disclosed in Patent Document 2, a scattering portion (light scattering resin portion 107) is formed on an upper surface of a sealing resin (sealing member 106) by an additional process such as cutting with a drill. Was. In other words, the LED devices disclosed in Patent Documents 1 and 2 have a structure in which additional processes such as coating and cutting are performed for correcting the emission color.

  Accordingly, an object of the present invention is to provide an LED device capable of correcting a luminescent color even with a structure obtained by a simple additional process in order to solve this problem.

In order to solve the above problems, the LED device of the present invention is:
An LED die,
A sealing resin that covers the upper surface of the LED die and contains a phosphor;
And a diffusion layer contained in the upper portion of the sealing resin and including a diffusion material.

  In the LED device of the present invention, the sealing resin covers the upper surface of the LED die. This sealing resin contains a phosphor and has a diffusion layer in the upper part thereof. The diffusion layer functions to return a part of the light emitted from the LED die to the inside of the sealing resin, and the wavelength of the returned light is converted by the phosphor. As a result, compared with the LED device without the diffusion layer, the LED device of the present invention having the diffusion layer shifts the emission color to the long wavelength side. Further, the diffusion layer can be easily formed by implanting diffusion particles (diffusion material) from above the sealing resin.

  The upper surface of the sealing resin may be a rough surface.

  The LED die may include an external connection electrode for connecting to the mother substrate.

  A reflection frame may be provided around and a part of the reflection frame may be a slope.

  The sealing resin may be dome-shaped.

  As described above, although the LED device of the present invention has a structure obtained by a simple additional process, the emission color can be corrected.

The sectional view of the LED device in a 1st embodiment of the present invention. Sectional drawing of the LED apparatus in 2nd Embodiment of this invention. Sectional drawing of the LED apparatus in 3rd Embodiment of this invention. Sectional drawing of the conventional LED device.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted. For the sake of explanation, the scale of the members is changed as appropriate.

(First embodiment)
The LED device 10 in the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of the LED device 10. As shown in FIG. 1, the LED device 10 includes a submount substrate 13.
The LED die 11 is flip-chip mounted thereon, and the periphery of the LED die 11 and the upper surface of the submount substrate 13 are covered with a sealing resin 15. The LED die 11 is provided with two internal connection electrodes 12, and the internal connection electrodes 12 are connected to wiring electrodes on a submount substrate 13 (not shown). Further, a diffusion layer 14 is present on the top of the sealing resin 15.

  The submount substrate 13 is made of resin, ceramic, metal having an insulating layer on the surface for insulation, and the like, and includes wiring electrodes and through holes. The LED die 11 is a blue light emitting diode, and a semiconductor layer and a transparent insulating substrate are laminated on the internal connection electrode 12. The semiconductor layer has a thickness of less than 10 μm and includes a p-type GaN layer and an n-type GaN layer. The light emitting layer is a boundary between the p-type GaN layer and the n-type GaN layer. The transparent insulating substrate is made of sapphire and has a thickness of about 150 μm.

  The sealing resin 15 is a silicone resin containing a phosphor, and the thickness from the upper surface to the upper surface of the transparent insulating substrate is about 300 μm. The diffusion layer 14 is formed by implanting a diffusion material made of SiO 2 having a diameter of less than 10 μm, titanium oxide, or alumina on the upper surface of the sealing resin 15 by a sandblasting method, and has a thickness of several tens of μm.

  First, light emission of the LED device 10 will be described. Part of the light emitted from the LED die 11 passes through the sealing resin 15 and the diffusion layer 14 and is emitted to the outside. The remaining part of the light emitted from the LED die 11 is wavelength-converted by the phosphor in the sealing resin 15 and then emitted to the outside of the LED device 10. Another part of the light emitted from the LED die 11 is returned downward by the diffusion layer 14, wavelength-converted by the phosphor in the sealing resin 15, and then emitted to the outside of the LED device 10.

  Next, correction of the emission color will be described. First, the emission color (chromaticity) of the LED device 10a without the diffusion layer 14 (which becomes the LED device 10 when the diffusion layer 14 is formed) is measured. A difference from the target chromaticity is obtained, and based on a correction table prepared in advance, a diffusion material is sprayed from the upper part of the LED device 10a by the sandblast method. In the correction table, conditions for sandblast pressure and time are set according to the correction amount. Further, the diffusion material enters the sealing resin 15 by sandblasting to form the diffusion layer 14. As described above, the LED device 10 corrected to a desired emission color is obtained.

  This correction method can only correct to the yellow side (long wavelength side). For the LED device 10a that needs to be corrected to the blue side (short wavelength side), for example, the surface of the sealing resin 15 may be smoothly cut to reduce the phosphor. Alternatively, the upper portion of the LED die 11 may be masked to form a diffusion layer only in the region on the upper surface of the sealing material 15 that is larger than the critical angle of light emission from the LED die 11 to increase the amount of blue light emitted. In the LED device 10, the LED die 11 is flip-chip mounted on the submount substrate 13. However, the LED die mounting method is not limited to flip chip mounting. For example, the LED die is bonded to the submount substrate by wire bonding and the electrode is formed by wire bonding. An inter-connection may be taken.

(Second Embodiment)
The LED device 10 (see FIG. 1) shown as the first embodiment includes the submount substrate 13. However, in the case of aiming to reduce the components and reduce the size, the LED device of the present invention does not use the submount substrate. Also good. Further, since the LED device 10 has only covered the LED die 11 with the translucent sealing resin 15, the LED device 10 also emits light to the side of the LED device 10. On the other hand, in applications where the light distribution is narrowed, such as a light source for flash, the light traveling to the side may be harmful. That is, as is generally known, the LED device of the present invention may also include a reflective frame on the side of the LED device. Furthermore, although the upper surface of the sealing resin 15 of the LED device 10 is flat, the upper surface of the sealing member 15 may be roughened to prevent a decrease in light emission efficiency due to total reflection.
Therefore, referring to FIG. 2, an LED device 20 having no submount substrate, including a reflection frame around it, and having a rough upper surface will be described as a second embodiment.

  FIG. 2 is a cross-sectional view of the LED device 20. In FIG. 2, the upper surface and the side surface of the LED die 11a are covered with a sealing resin 15a, and a diffusion layer 14a is present in the upper portion of the sealing resin 15a. Below the LED die 11a is an external connection electrode 12a for connecting the LED die 11a itself to the mother board. The external connection electrode 12a corresponds to an anode and a cathode, and is adjusted to a size that can be easily mounted on the semiconductor layer included in the LED die 11a by an interlayer insulating film or a multilayer wiring. The mother board is a large board on which other electronic components such as resistors and capacitors may be mounted.

  A reflection frame 21 exists around the sealing resin 15 a, and a slope 22 is provided at the bottom of the reflection frame 21. The reflection frame 21 is obtained by kneading and curing reflective fine particles such as titanium oxide and alumina in a silicone resin, and has a thickness of about 100 μm.

  If the side surface of the LED die 11a is in contact with the reflecting frame 21 (hereinafter referred to as the LED device 20a), the light emitted from the side surface of the transparent insulating substrate of the LED die 11a is reflected by the reflecting frame 21 and again is the transparent insulating substrate. Come back in. This light is reabsorbed by the semiconductor layer of the LED die 11a or becomes stray light, thereby reducing the light emission efficiency of the LED device 20a. On the other hand, in the LED device 20 of the present embodiment, since the sealing resin 15a exists between the side surface of the LED die 11a and the reflection frame 21, light emitted from the side surface of the LED die 11a is guided at this portion and the LED device. 20 is emitted to the outside. As a result, the light emission efficiency of the LED device 20 is improved as compared with the LED device 20a. Furthermore, it has been confirmed that if the slope 22 is provided at the bottom of the reflection frame 21, the luminous efficiency is improved.

  The rough surface 23 formed on the upper surface of the sealing resin 15a is formed simultaneously with the implantation of the diffusion material when the diffusion layer 14a is formed by the sandblast method. By roughening the upper surface of the sealing resin 15a as described above, the total reflection that occurs at the interface between the sealing resin 15a and the air can be eliminated, so that the light emission efficiency of the LED device 20 is improved. Since the rough surface 23 causes the emission color to shift similarly to the diffusion layer 14a, it is necessary to consider the influence of the rough surface 23 in correcting the emission color by the diffusion layer 14a.

(Third embodiment)
In the LED device 20 shown as the second embodiment, the top surface of the sealing resin 15a is roughened to improve the light emission efficiency. However, the light emission efficiency may be improved by making the sealing resin into a dome shape. Therefore, FIG. 3 illustrates an LED device 30 in which a sealing resin is formed in a dome shape as a third embodiment of the present invention.

  FIG. 3 is a cross section of the LED device 30. 3, the same reference numerals as those in FIG. 1 denote the same members, and the description thereof is omitted. The only difference between the LED device 30 and the LED device 10 of FIG. 1 is the shape of the sealing resin 15b shown in FIG. 3 and the sealing resin 15 shown in FIG. Along with this difference, the shape of the diffusion layer 14 b existing above the sealing resin 15 b is also different from the shape of the diffusion layer 14 of the LED device 10.

  In FIG. 3, the sealing resin 15b is formed in a dome shape. For this reason, the incident angle of the light which is going to be emitted to the outside from the sealing resin 15b becomes small, and total reflection hardly occurs. Since the diffusion layer 14b can also be formed by simply driving a diffusion material from the upper part of the LED device 30 by sandblasting, the emission color can be corrected with a simple additional process.

In the LED device 20 shown in FIG. 2, the upper surface of the sealing resin 15 a is a rough surface 23. Figure 1
The LED devices 10 and 30 shown in FIG. 3 can also improve the light emission efficiency by roughening the upper surfaces of the sealing resins 15 and 15b. At this time, the rough surface can be formed simultaneously with the diffusion layers 14 and 14b. Further, the LED device 20 has a reflection frame around it, and a part of the reflection frame 21 is a slope 22. The LED devices 10 and 30 may be provided with a reflection frame around and part of them may be a slope. Further, in the LED devices 10 and 20, the sealing resins 15 and 15a may be formed in a dome shape.

10, 20, 30 ... LED device,
11, 11a ... LED die,
12 ... internal connection electrodes,
12a ... external connection electrode,
13 ... Submount substrate,
14, 14a, 14b ... diffusion layer,
15, 15a, 15b ... sealing resin,
21 ... Reflective frame,
22 ... Slope,
23 ... rough surface.

Claims (5)

An LED die,
A sealing resin that covers the upper surface of the LED die and contains a phosphor;
An LED device comprising: a diffusion layer that is present above the sealing resin and includes a diffusion material.   The LED device according to claim 1, wherein an upper surface of the sealing resin is a rough surface.   The LED device according to claim 1, wherein the LED die includes an external connection electrode for connecting to a mother substrate.   4. The LED device according to claim 1, further comprising a reflection frame around the periphery, wherein a part of the reflection frame is an inclined surface. 5.   The LED device according to claim 1, wherein the sealing resin has a dome shape.

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