JP2008171931A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device which has high emission efficiency, shows no color irregularity etc., suppresses the shrinkage of a thermosetting resin when the thermosetting resin sets to eliminate a wrinkle, and hardly allows interface separation between a resin layer and a frame, light-emitting element, etc., to occur even when used under a high temperature and high humidity. <P>SOLUTION: The light-emitting device includes a basic substance 3 having a recession 7, a light-emitting element placed in the recession 7, and a bubbleless phosphor-containing resin layer 9 which is formed in the recession 7 to cover the light-emitting element, contains a phosphor excited by light emitted from a thermosetting resin and the light-emitting element to emit visible light, and has a projection area 5% or more of the upper surface area of the light-emitting element on the side closer to a light extraction direction than the upper surface of the light-emitting element. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light emitting device such as an LED lamp.

  LED lamps using light emitting diodes (LEDs) are rapidly expanding in various fields such as backlights for liquid crystal displays, mobile phones, information terminals, indoor / outdoor advertisements, and the like. Furthermore, LED lamps have features such as long life and high reliability, and low power consumption, impact resistance, high-speed response, high purity display color, lightness, and shortening. It is also in the spotlight for general lighting. When such an LED lamp is applied to various uses, it is important to obtain white light emission.

  As a typical method for realizing white light emission with an LED lamp, (1) a method using three LED chips emitting light in blue, green and red colors, and (2) a blue light emitting LED chip and yellow to orange light emission. There are three types: (3) a method of combining an LED chip that emits ultraviolet light and a three-color mixed phosphor of blue, green, and red light emission (hereinafter referred to as RGB phosphor). Can be mentioned. Of these, the method (2) is generally widely used.

  As the structure of the LED lamp to which the above-described method (2) is applied, a transparent resin mixed with a phosphor is poured into a cup-shaped frame equipped with an LED chip, and the resin layer containing the phosphor is solidified by pouring it. A structure in which is formed is proposed (see, for example, Patent Document 1). Also, a chip-on-board (COB) in which a phosphor-containing resin layer is formed by applying a transparent resin mixed with a phosphor on a large number of LED chips mounted on a substrate (board) for the purpose of increasing brightness. : Chip On Board) structure has also been developed. Furthermore, a cup module has been proposed in which 1 to 5 LED chips are provided in one cup, and a large number of lamps having such a cup structure are mounted on one large board.

  In order to manufacture the LED lamp and the LED module having such a structure, after the LED chip is mounted at a predetermined position and wire bonding is performed, a liquid thermosetting resin in which a phosphor is dispersed is dispensed. For example, a method is used in which a phosphor-containing resin layer is formed by pouring into a frame or the like in which an LED chip is disposed by heating and curing a thermosetting resin.

In the formation of such a phosphor-containing resin layer, it is most important to disperse phosphors and remove foreign substances such as bubbles (hereinafter simply referred to as bubbles). From the viewpoint of reliability and stability, There is a demand for LED lamps or modules in which the phosphor is completely dispersed and the generation of bubbles in the resin layer is small.
JP 2001-148516 A

  However, in conventional LED lamps and LED modules, especially COB modules and large cup modules, the temperature rise due to heat conduction is slow in the heating / curing process of the thermosetting resin. If it is not set higher than that, the phosphor will settle in the resin, resulting in a problem that the luminous efficiency is lowered. However, if the set temperature of the furnace is too high, many bubbles are generated in the resin layer being cured, and this may remain in the resin layer as it is after curing. If bubbles remain in the resin layer, it causes a decrease in light transmission characteristics and variations. That is, light emitted from the LED chip is difficult to hit the phosphor due to bubbles remaining in the resin layer, so that excitation of the phosphor is inhibited, and light emitted from the phosphor strikes the bubbles and diffuses. For this reason, light emission in the light extraction direction is hindered, resulting in uneven brightness and uneven colors.

  Furthermore, if bubbles remain in the resin layer, the shrinkage when the resin cures may increase, and the appearance may be wrinkled. Also, when used for a long period of time, especially when used under high temperature and high humidity, There is a possibility that peeling occurs between the interface between the layer and the frame, the LED chip, or the like, or a bonding wire connected to the LED chip. When such peeling occurs, the brightness is significantly reduced.

  In addition, the above-mentioned bubbles are the result of the micro bubbles originally contained in the resin material growing into large bubbles due to a sudden rise in temperature during curing, and the air entrained during resin injection (usually initially Is present at the corner of the bottom, and if it stays in that position, the effect on the light transmission characteristics is very small.) it is conceivable that.

  An object of the present invention is to provide a light emitting device that has high luminous efficiency and does not have uneven luminance or uneven color. In addition, the object of the present invention is to suppress shrinkage at the time of curing the thermosetting resin, there is no wrinkle, and even when used under high temperature and high humidity, the interface peeling between the resin layer and the frame, the light emitting element, etc. An object of the present invention is to provide a light emitting device in which peeling between a resin layer and a bonding wire connected to a light emitting element hardly occurs.

  The light-emitting device according to claim 1 is formed in the recess so as to cover the light-emitting element, the base having a recess, the light-emitting element disposed in the recess, and emitted from the thermosetting resin and the light-emitting element. And a phosphor having a projected area of 5% or more of the upper area of the light emitting element on the light extraction direction side from the upper surface of the light emitting element. And a phosphor-containing resin layer that is not included.

  The light emitting device according to claim 2 is the light emitting device according to claim 1, wherein the light emitting element is a light emitting element that emits blue light, and the phosphor is excited by the blue light emitted from the light emitting element. A yellow phosphor that emits light between yellow light and orange light.

  The light emitting device according to claim 3 is the light emitting device according to claim 1 or 2, characterized in that the thermosetting resin is a thermosetting silicone resin.

  A light emitting device according to a fourth aspect is the light emitting device according to any one of the first to third aspects, wherein a length of one side of the light emitting element is 50 nm to 800 nm.

  In the first to fourth inventions described above, the definitions and technical meanings of terms are as follows unless otherwise specified.

  The light emitting element is one that excites a phosphor with emitted light to emit visible light, and examples thereof include a blue light emitting type LED chip and an ultraviolet light emitting type LED chip. However, the light-emitting element is not limited thereto, and various light-emitting elements can be used depending on the use of the light-emitting device, the target light emission color, or the like as long as the light-emitting element can excite the phosphor and emit visible light. Can be used.

  The phosphor is excited by light emitted from such a light emitting element (for example, blue light) to emit visible light, and is emitted by a color mixture of the visible light and light emitted from the light emitting element or from the phosphor. As a light emitting device, a desired light emission color is obtained by the visible light or color mixture of visible light itself. The type of the phosphor is not particularly limited, and is appropriately selected according to the intended emission color, light emitted from the light emitting element, and the like.

  The phosphor-containing resin layer is a layer that holds the phosphor. The phosphor-containing resin layer is formed by mixing a transparent thermosetting resin and the phosphor so as to cover the light emitting element and solidifying it. As the thermosetting resin, for example, a transparent thermosetting resin such as an epoxy resin or a silicone resin can be used. In order to improve the luminous efficiency, the blending ratio of the phosphor to the resin is 6 to 20% by weight in total, and the thickness of the phosphor-containing resin layer corresponding to the optical path length is 0.5 to 1. 2 mm is preferable.

  In this invention, it is comprised so that the bubble beyond a fixed magnitude | size may not exist in the light extraction direction side above the upper surface of the light emitting element in such a fluorescent substance containing resin layer. The boundary value of the bubble size is a value that is 5% of the upper area (upper surface area) of the light emitting element as a projected area on the upper surface of the light emitting element. That is, in the present invention, there is no bubble in the phosphor-containing resin layer, or even if it is present, the size of the bubble (one piece) is less than 5% of the upper area of the light emitting element. To do. In the present invention, bubbles having a projected area of 5% or more of the upper area of the light emitting element do not exist in the light extraction direction, so that excitation of the phosphor is inhibited or extraction of light emitted from the phosphor is inhibited. It will never be done.

  According to the first aspect of the present invention, bubbles having a projected area of 5% or more of the upper area of the light-emitting element do not exist in the light extraction direction in the phosphor-containing resin layer. Extraction of light emission from the body is not hindered, and a light emitting device with high luminous efficiency and no luminance unevenness and color unevenness can be realized. In addition, since shrinkage associated with the curing of the thermosetting resin can be reduced, the generation of wrinkles in the resin layer can be suppressed, and the interface between the resin layer and the frame, the light emitting element, etc. associated with long-term use can be suppressed. In addition, peeling between the resin layer and the bonding wire can be suppressed, and a light emitting device with excellent reliability can be obtained.

  According to the second aspect of the present invention, it is possible to realize a so-called light bulb-colored light emitting device that has high luminous efficiency and does not have luminance unevenness or color unevenness.

  According to the inventions according to claims 3 and 4, it is possible to realize a light emitting device with even higher luminous efficiency and no luminance unevenness and color unevenness.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that, in the plurality of drawings referred to below, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a cross-sectional view showing a configuration of a first embodiment in which the light emitting device of the present invention is applied to an LED lamp. FIG. 2 shows a plurality of LED lamps shown in FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2, and FIG. 3 is a plan view showing an example of LED modules arranged in a matrix of rows.

  The LED lamp 1 shown in FIGS. 1 to 3 has an LED chip 2 as a light emitting element. As the LED chip 2, for example, a blue light emitting type LED chip, an ultraviolet light emitting type LED chip, or the like is used. The LED chip 2 is mounted on a circuit pattern 5 provided on a substrate 3 via an electrical insulating layer 4.

  The substrate 3 is made of a flat plate made of aluminum (Al), nickel (Ni), glass epoxy or the like having heat dissipation and rigidity, and the circuit pattern 5 is made of an alloy of copper (Cu) and nickel (Ni), gold (Au ) And the like, the circuit patterns 5a and 5b on the anode side and the cathode side are formed. In the LED chip 2, the bottom electrode is placed on one of the circuit patterns 5a and 5b, for example, the anode side circuit pattern 5a to be electrically connected, and the top electrode is connected to the other of the circuit patterns 5a and 5b, for example, the cathode side circuit. The pattern 5b is electrically connected by a bonding wire 6 such as a gold wire. As an electrode connection structure of the LED chip 2, a flip chip connection structure can also be applied. According to these electrode connection structures, the light extraction efficiency to the front surface of the LED chip 2 is improved.

  On the substrate 3, there is provided a frame 8 that forms a truncated cone-shaped recess 7 that gradually increases in diameter upward, and the LED chip 2 is disposed in the recess 7. The concave portion 7 is formed in a truncated cone shape having a bottom surface diameter of 2.0 to 4.0 mm, a top surface diameter of 1.5 to 4.5 mm, and a depth of 0.5 to 1.0 mm, for example. For example, it is made of polybutylene terephthalate (PBT), polyphthalamide (PPA), polycarbonate (PC) or the like.

  In the recess 7 in which the LED chip 2 is disposed, a phosphor-containing resin layer 9 made of a transparent thermosetting resin containing a phosphor is provided. The LED chip 2 is formed by the phosphor-containing resin layer 9. It is covered. The phosphor-containing resin layer 9 injects (drops / applies) a transparent liquid thermosetting resin mixed with the phosphor into the recess 7 in which the LED chip 2 is disposed using an injection device such as a dispenser, For example, it is formed by heat-curing by a method described later. The injection amount of the liquid thermosetting resin mixed with the phosphor is preferably about 5 to 10 mg. In the drawing, the upper end surface of the phosphor-containing resin layer 9 is formed substantially flush with the upper end of the concave portion 7, but the present invention is not limited to this.

  The phosphor-containing resin layer 9 has a function as a light emitting part as well as a function of sealing the LED chip 2 in the recess 7. That is, the phosphor contained in the phosphor-containing resin layer 9 is excited by light emitted from the LED chip 2, for example, blue light or ultraviolet light, and emits visible light.

  Here, examples of the transparent liquid thermosetting resin used for forming the phosphor-containing resin layer 9 include a silicone resin and an epoxy resin. The use of a liquid silicone resin is preferred. From the viewpoint of ease of injection, it is particularly preferable to use a silicone resin having a viscosity at 25 ° C. of 0.5 to 70 Pa · s. Moreover, the fluorescent substance contained in such a thermosetting resin is not specifically limited, According to the luminescent color etc. of the target LED lamp 1, it can select suitably.

For example, when the white light emission is obtained using the blue light emitting type LED chip 2, a yellow phosphor that emits light between yellow light and orange light is mainly used. Further, in order to improve the color rendering properties and the like, a red light emitting phosphor may be used in addition to the yellow phosphor. As the yellow phosphor that emits light between yellow light and orange light, for example, RE ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphor (RE represents at least one selected from Y, Gd, and La). Silicate phosphors such as YAG phosphors such as AE ₂ SiO ₄ : Eu phosphor (AE is an alkaline earth element such as Sr, Ba, Ca, etc .; the same shall apply hereinafter).

Further, when white light emission is obtained using the ultraviolet light emitting type LED chip 2, RGB phosphors are mainly used. Examples of blue light emitting phosphors include halophosphate phosphors such as AE ₁₀ (PO ₄ ) ₆ Cl ₁₂ : Eu phosphor and aluminate fluorescence such as (Ba, Mg) Al ₁₀ O ₁₇ : Eu phosphor. The body is used. As the green light emitting phosphor, an aluminate phosphor such as a (Ba, Mg) Al ₁₀ O ₁₇ : Eu, Mn phosphor is used. As the red light emitting phosphor, an oxysulfide phosphor such as a La ₂ O ₂ S: Eu phosphor is used.

Further, in place of the above phosphors, nitride phosphors (for example, AE ₂ Si ₅ N ₈ : Eu) and oxynitride phosphors (for example, Y ₂ ) capable of obtaining various emission colors depending on the composition. Si ₃ O ₃ N ₄ : Ce), sialon-based phosphors (for example, AE _x (Si, Al) ₁₂ (N, O) ₁₆ : Eu), or the like may be applied. The LED lamp 1 is not limited to the white light emitting lamp, and the LED lamp 1 having a light emitting color other than white can be configured. When the LED lamp 1 emits light other than white, for example, light of an intermediate color, various phosphors are appropriately used depending on the target light emission color.

In the phosphor-containing resin layer 9 containing such a phosphor, bubbles having a projected area of 5% or more of the upper area of the LED chip 2 are formed above the upper surface of the LED chip 2 in the light extraction direction. It is configured not to exist. For example, when the length of one side of the LED chip 2 is 100 μm (0.1 mm), bubbles having a projected area of 0.0005 mm ² or more on the light extraction direction side of the phosphor-containing resin layer 9, that is, There are no bubbles with a radius of 0.0126 mm (12.6 μm) or more.

  In order to prevent bubbles of a certain size or more from being present in this way, in the heating / curing process of the thermosetting resin, the set temperature of the heating furnace and the work (the LED lamp or LED module that is the object to be processed) It is preferable to adopt a method of controlling the heating conditions such as the temperature rising rate. In other words, in the process of heating and curing the liquid thermosetting resin mixed with the phosphor, the temperature is raised by adjusting the set temperature of the heating furnace or by changing the type and thickness of the auxiliary plate on which the workpiece is placed. By controlling the speed, it is possible to prevent bubbles larger than a certain size from being present.

  In addition, multi-stage heating including a first heating step of heating at a first predetermined temperature and a second heating step of heating at a second predetermined temperature higher than the first predetermined temperature can be performed. By curing the thermosetting resin by multistage heating, it is possible to avoid a rapid temperature rise of the thermosetting resin, so that the generation of bubbles during curing of the thermosetting resin is suppressed, and the phosphor-containing resin There can be no bubbles of a certain size in the layer 9

  In the multi-stage heating, first, as a first heating process, heating is performed under the condition that the thermosetting resin is in a semi-cured state, and then a second heating process is performed in which the temperature is raised and the thermosetting resin is completely cured. The heating conditions in each of the first and second heating steps depend on the type of thermosetting resin and the injection amount thereof, the material and size of the substrate 3 and the frame 8, the size of the recess 7 formed on the frame 8, and the like. However, usually, the first heating step is performed at a temperature of 80 to 110 ° C., and the second heating step is performed at a temperature higher than the temperature of the first heating step, preferably 100 to 150 ° C. .

  Further, the first predetermined temperature, which is the heating temperature in the first heating step, is a temperature between the curing start temperature of the thermosetting resin (for example, thermosetting silicone resin) and the curing temperature, and heating is performed at this temperature. Then, after the thermosetting silicone resin is semi-cured, it is possible to adopt a method in which it is completely cured by heating at a second predetermined temperature higher than the first predetermined temperature in the second heating step.

  According to the first embodiment of the present invention, since bubbles having a projected area of 5% or more of the upper area of the LED chip 2 do not exist in the light extraction direction in the phosphor-containing resin layer 9, excitation of the phosphor Is not inhibited, and the extraction of light emission from the phosphor is not inhibited. Therefore, a light-emitting device with high light emission efficiency and no luminance unevenness and color unevenness can be realized. In addition, shrinkage associated with the curing of the thermosetting resin can be reduced, whereby generation of wrinkles in the resin layer can be suppressed, and the resin layer and the frame 8 and the LED chip 2 associated with long-term use can be suppressed. Etc., and the peeling between the resin layer and the bonding wire 6 connected to the LED chip 2 can be suppressed, and the LED lamp 1 having excellent reliability can be obtained.

  In this embodiment, the flat type SMD type LED lamp 1 has been described as an example. However, the present invention is not particularly limited, and can be applied to, for example, a bullet type (or round type) LED lamp. Moreover, although the LED module 21 in which a plurality of LED lamps 1 are arranged in a matrix has been described, the present invention is not limited to this, and for example, the plurality of LED lamps 1 may be formed in a single row, Furthermore, each LED lamp 1 may be single.

  4 and 5 show a light-emitting device for forming an LED package according to the second embodiment of the present invention. FIG. 4 is a plan view of the light emitting device, and FIG. 5 is a longitudinal sectional view of the light emitting device shown in FIG. 4 cut along the line FF. 4 and 5, the same reference numerals are used for the same components as those in the drawings relating to the first embodiment, and the description thereof is simplified or omitted.

  A light-emitting device (LED lamp) 1 shown in FIGS. 4 and 5 includes a package substrate such as a device substrate 3, a reflective layer 31, a circuit pattern 5, a plurality of semiconductor light-emitting elements such as LED chips 2, and an adhesive layer. 32, a reflector 34, a phosphor-containing resin layer 9, and a light diffusing member 33. The phosphor-containing resin layer 9 also functions as a sealing member.

  The device substrate 3 is made of a flat plate made of a metal or an insulating material such as a synthetic resin, and has a predetermined shape such as a rectangular shape in order to obtain a light emitting area required for the light emitting device 1. When the device substrate 3 is made of a synthetic resin, it can be formed of, for example, an epoxy resin containing glass powder. When the device substrate 3 is made of metal, the heat radiation from the back surface of the device substrate 3 is improved, the temperature of each part of the device substrate 3 can be made uniform, and the semiconductor light emitting element 2 that emits light in the same wavelength range. The variation in the emission color can be suppressed. In addition, as a metal material which has such an effect, the material excellent in the heat conductivity of 10 W / m * K or more, specifically, aluminum or its alloy can be illustrated.

  The reflective layer 31 is sized so that a predetermined number of semiconductor light emitting elements 2 can be disposed, and is, for example, attached to the entire surface of the device substrate 3. The reflective layer 31 can be made of a white insulating material having a reflectance of 85% or more in the wavelength region of 400 to 740 nm. As such a white insulating material, a prepreg made of an adhesive sheet can be used. Such a prepreg can be formed, for example, by impregnating a sheet base material with a thermosetting resin mixed with a white powder such as aluminum oxide. The reflective layer 31 is bonded to the entire surface of the device substrate 3 by its own adhesiveness.

  The circuit pattern 5 is bonded to a surface of the reflective layer 31 opposite to the surface to which the device substrate 3 is bonded as an energizing element for each semiconductor light emitting element 2. For example, the circuit patterns 5 are formed in two rows scattered at predetermined intervals in the longitudinal direction of the device substrate 3 and the reflective layer 31 in order to connect the semiconductor light emitting elements 2 in series. The end-side circuit pattern 5a located on one end side of the row of one circuit pattern 5 is integrally formed with a power feeding pattern portion 5c. Similarly, the end located on one end side of the row of the other circuit pattern 5 The side circuit pattern 5a is integrally formed with a power feeding pattern portion 5d.

  The power supply pattern portions 5 c and 5 d are provided side by side at one end in the longitudinal direction of the reflective layer 31 and are separated from each other and insulated by the reflective layer 31. An electric wire (not shown) reaching the power source is individually connected to each of the power supply pattern portions 5c and 5d by soldering or the like.

  The circuit pattern 5 is formed by the procedure described below. First, a reflective layer 31 made of a prepreg impregnated with the uncured thermosetting resin is stuck on the device substrate 3, and then a copper foil of the same size is stuck on the reflective layer 31. Next, the laminated body thus obtained is heated and pressurized to cure the thermosetting resin, thereby pressing the device substrate 3 and the copper foil to the reflective layer 31 to complete the bonding. Next, after providing a resist layer on the copper foil and etching the copper foil, the remaining resist layer is removed to form the circuit pattern 5. The thickness of the circuit pattern 5 made of copper foil is, for example, 35 μm.

  Each semiconductor light emitting element 2 is made of, for example, a double wire type LED chip using a nitride semiconductor, and is formed by laminating a semiconductor light emitting layer 2a on one surface of an element substrate 2b having translucency. The element substrate 2b is made of, for example, a sapphire substrate. The element substrate 2b is thicker than the circuit pattern 5, for example, 90 μm.

  The semiconductor light emitting layer 2a is formed by sequentially stacking a buffer layer, an n-type semiconductor layer, a light emitting layer, a p-type cladding layer, and a p-type semiconductor layer on the main surface of the element substrate 2b. The light emitting layer has a quantum well structure in which barrier layers and well layers are alternately stacked. An n-side electrode is provided on the n-type semiconductor layer, and a p-side electrode is provided on the p-type semiconductor layer. This semiconductor light emitting layer 2a does not have a reflective film, and can emit light in both thickness directions.

  Each semiconductor light emitting element 2 is disposed between circuit patterns 5 adjacent to each other in the longitudinal direction of the device substrate 3, and is bonded to the same surface of the white reflective layer 31 by an adhesive layer 32. Specifically, the other surface parallel to one surface of the element substrate 2 b on which the semiconductor light emitting layer 2 a is laminated is bonded to the reflective layer 31 by the adhesive layer 32. By this adhesion, the circuit pattern 5 and the semiconductor light emitting element 2 are arranged in a straight line on the same surface of the reflective layer 31, so that the side surface of the semiconductor light emitting element 2 positioned in this arrangement direction and the circuit pattern 5 are close to each other. It is provided so as to face each other.

  The thickness of the adhesive layer 32 can be, for example, 5 μm or less. For the adhesive layer 32, for example, a translucent adhesive having a thickness of 5 μm or less and a light transmittance of 70% or more, for example, a silicone resin-based adhesive can be suitably used.

  As shown in FIGS. 4 and 5, the electrode of each semiconductor light emitting element 2 and the circuit pattern 5 arranged close to both sides of the semiconductor light emitting element 2 are connected by a bonding wire 6. Further, the end-side circuit patterns 5b positioned on the other end side of the two rows of circuit patterns 3 rows are also connected by bonding wires 6. Therefore, in this embodiment, each semiconductor light emitting element 2 is connected in series.

  The surface emitting source of the light emitting device 1 is formed by the device substrate 3, the reflective layer 31, the circuit pattern 5, each semiconductor light emitting element 2, the adhesive layer 32, and the bonding wire 6.

  The reflector 34 is not individually provided for each one or several semiconductor light emitting elements 2, but is a single one surrounding all the semiconductor light emitting elements 2 on the reflective layer 31, for example, as shown in FIG. Thus, it is formed with a rectangular frame, and the semiconductor light emitting element 2 is disposed in a recess 7 formed with the frame. The reflector 34 is bonded to the reflective layer 31, and a plurality of semiconductor light emitting elements 2 and circuit patterns 5 are housed therein, and the pair of power feeding pattern portions 5 c and 5 d are positioned outside the reflector 34. ing.

  The reflector 34 can be formed of, for example, a synthetic resin, and its inner peripheral surface is a reflective surface. The reflecting surface of the reflector 34 can be formed by vapor deposition or plating of a metal material having a high reflectance such as Al or Ni, or can be formed by applying a white paint having a high visible light reflectance. Alternatively, white powder can be mixed into the molding material of the reflector 34 to make the reflector 34 itself white with high visible light reflectivity. As the white powder, a white filler such as aluminum oxide, titanium oxide, magnesium oxide or barium sulfate can be used. In addition, it is desirable to form the reflecting surface of the reflector 34 so as to gradually open in the irradiation direction of the light emitting device 1.

  As in the first embodiment, the phosphor-containing resin layer 9 was arranged on the surface of the reflective layer 31 and in a straight line by using a liquid thermosetting resin mixed with a phosphor using an injection device such as a dispenser. The semiconductor light emitting elements 2 and the bonding wires 6 are filled so as to be filled evenly. For example, the first heating step of heating at the first predetermined temperature and the second higher than the first predetermined temperature as described above. It is formed by curing the thermosetting resin by multi-stage heating including a second heating step of heating at a predetermined temperature.

  The liquid transparent resin that flows between the surface of the reflective layer 31 and the bonding wire 6 reaches each semiconductor light emitting element 2 and the bonding wire 6 due to a capillary phenomenon or the like, and the film thickness thereof is almost uniform. The body is also almost uniformly dispersed in the transparent resin. In the phosphor-containing resin layer 9, there is no bubble having a projected area of 5% or more of the upper area of the semiconductor light emitting element 2 on the light extraction direction side from the upper surface of the semiconductor light emitting element 2. Yes.

  Also in the second embodiment configured as described above, since bubbles having a projected area of 5% or more of the upper area of the semiconductor light emitting element 2 do not exist in the light extraction direction in the phosphor-containing resin layer 9, the phosphor Excitation of light is not hindered or light emission from the phosphor is not hindered, and a light emitting device with high luminous efficiency and no unevenness in brightness and color can be realized. Further, since shrinkage due to curing is reduced, wrinkles of the resin layer after curing, interface peeling between the resin layer and the frame, the semiconductor light emitting element 2, and the like, a bonding wire 6 connected to the resin layer and the semiconductor light emitting element 2 It is possible to suppress the occurrence of peeling.

  Next, examples of the present invention and evaluation results thereof will be described.

Examples 1-3, Comparative Examples 1-5
The phosphor-containing resin layer 9 of the LED lamp 1 having the configuration shown in FIG. 1 was formed as follows. That is, a liquid thermosetting silicone resin (viscosity at 25 ° C. of 3 Pa · s) obtained by mixing the main agent and the curing agent in a ratio of 1: 1 is applied to a vacuum defoaming apparatus, and then the foam is removed. A phosphor containing 10% by weight of the following phosphor (particle size: 10 to 15 μm) was dropped and applied in the recess 7 with a dispenser. In Examples 1 and 2 and Comparative Examples 1 to 3, a blue LED chip (main wavelength: 460 nm) having a side length of 100 μm (upper area 0.01 mm ² ) was used as the light emitting element. 3 and Comparative Examples 4 and 5, a blue LED chip (main wavelength: 460 nm) having a side length of 300 μm (upper area 0.09 mm ² ) was used. Also, a yellow phosphor having a main wavelength of 540 nm, a yellow phosphor having a main wavelength of 585 nm, and a red phosphor having a main wavelength of 650 nm are mixed at a weight ratio (%) of the resin of 4.0: 3.5: 2.5. Used. Then, this phosphor-containing silicone resin was injected into a truncated cone-shaped concave portion 7 having an opening diameter of 3.0 mm, a reflector angle of 63 degrees, and a depth of 1 mm so as to have an optical path length of 1 mm.

  Next, in Examples 1 to 3, the thermosetting silicone resin was heat-cured by two-stage heat treatment at 80 ° C. for 60 minutes and 120 ° C. for 60 minutes, and the LED lamp 1 was produced. In each example, the heating rate was changed by changing the thickness of the auxiliary plate on which the object to be processed was placed. In Comparative Examples 1 to 5, the thermosetting silicone resin was cured by heating at 150 ° C. for 60 minutes to produce LED lamps 1. In each comparative example, the rate of temperature increase was changed by changing the thickness of the auxiliary plate on which the workpiece was placed.

  Thus, in the LED lamp 1 obtained by Examples 1-3 and Comparative Examples 1-5, the magnitude | size of the bubble in the fluorescent substance containing resin layer 9 was measured as shown below. That is, the phosphor-containing resin layer 9 was cut above the LED chip 2 (on the light extraction direction side), the cut surface was magnified 1000 times with a metal microscope or SEM, and the diameter of bubbles present on the cut surface was measured. The measurement results are shown in Table 1 and Table 2, respectively.

  Next, the LED lamps 1 obtained in Examples 1 to 3 and Comparative Examples 1 to 5 were each made to emit light, and the emission spectrum was measured with an instantaneous spectrophotometer MCPD-7000 (manufactured by Otsuka Electronics Co., Ltd.). The color temperature (Tc) was calculated from the emission spectrum. Further, an emission spectrum at an observation angle of 70 degrees was measured, an angular color difference (Δuv) was calculated, and the presence or absence of color unevenness was determined with the naked eye. Moreover, the luminous efficiency was measured using the gonio method. These measurement results are shown in Tables 1 and 2.

  The luminous efficiency is a relative value when the efficiency of the LED lamp of Example 1 is 100%. In addition, the color unevenness was indicated as “◯” when the color unevenness was not noticed by the naked eye, “Δ” when there was a slight color unevenness but not enough, and “X” when the color unevenness was felt.

The angle color difference indicates the color difference for each observation angle. The observation angle is a line connecting the observation point and the center of the upper surface of the phosphor-containing resin layer 9 with a line passing through the center of the upper surface of the phosphor-containing resin layer 9 and being perpendicular to the upper surface of the layer as an axis (0 degree). This is the angle θ formed with the axis, and the angular color difference (Δuv) at the observation angle θ degree can be obtained from the u value and v value of the CIE 1976 UCS system chromaticity diagram by the following equation (1).
Δuv = {(u _θ −u ₀ ) ² + (v _θ −v ₀ ) ² } ^1/2 (1)

Here, u _θ and v _θ are the u value and the v value when the emission spectrum at a wavelength of 380 to 780 nm is measured at the observation angle θ degree, and u ₀ and v ₀ are the wavelength 380 at the observation angle of 0 degree. It is u value and v value when the emission spectrum of ˜780 nm is measured. As the angular color difference (Δuv) increases, the color temperature of white light changes according to the observation angle.

  As is clear from Tables 1 and 2, in Examples 1 to 3 in which the silicone resin was heat-cured by two-stage heating, the upper area of the LED chip in the silicone resin layer on the light extraction direction side from the upper surface of the LED chip. Since there is no bubble having a projected area of 5% or more, the luminous efficiency is high and the angle color difference (Δuv) at an observation angle of 70 degrees is small. In particular, Example 1 and Implementation in which the length of one side of the blue LED chip is 100 μm and the bubbles present in the silicone resin layer are less than 5% (3% and 4%) of the upper area of the LED chip In the LED lamp of Example 2, the angular color difference (Δuv) at an observation angle of 70 degrees was as small as 0.012 or less, and an LED lamp with little color unevenness (color variation) could be realized.

It is sectional drawing which shows the structure of 1st Embodiment which applied the light-emitting device of this invention to the LED lamp. It is a top view which shows an example of the LED module which has arrange | positioned two or more LED lamps shown in FIG. It is the III-III sectional view taken on the line of FIG. It is a top view of the light-emitting device concerning 2nd Embodiment of the light-emitting device of this invention. It is the FF sectional view taken on the line of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... LED lamp, 2 ... LED chip, 3 ... Board | substrate, 4 ... Electrical insulation layer, 5 ... Circuit pattern, 6 ... Bonding wire, 7 ... Recessed part, 8 ... Frame, 9 ... Phosphor containing resin layer, 21 ... LED module .

Claims (4)

A substrate having a recess;
A light emitting device disposed in the recess;
A layer formed in the recess so as to cover the light-emitting element, and containing a thermosetting resin and a phosphor that emits visible light when excited by light emitted from the light-emitting element; A phosphor-containing resin layer having no bubbles having a projected area of 5% or more of the upper area of the light emitting element on the light extraction direction side;
A light-emitting device comprising:   The light emitting element is a light emitting element that emits blue light, and the phosphor is a yellow phosphor that is excited by blue light emitted from the light emitting element to emit light between yellow light and orange light. The light-emitting device according to claim 1.   The light emitting device according to claim 1, wherein the thermosetting resin is a thermosetting silicone resin.   4. The light-emitting device according to claim 1, wherein a length of one side of the light-emitting element is 50 nm to 800 nm.

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