JP4269709B2 - Light emitting device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a light-emitting device used for various light sources such as a backlight light source, a display, and an illumination, and an optical sensor, and more particularly to a light-emitting device that combines good reliability and optical characteristics.
[0002]
[Prior art]
  Today, high-luminance and high-power semiconductor light-emitting elements and small and highly sensitive light-emitting devices have been developed and used in various fields. Such a light-emitting device is utilized for, for example, a light source of an optical printer head, a light source of a liquid crystal backlight, a light source of various meters, various reading sensors, and the like, taking advantage of features such as low power consumption, small size, and light weight.
[0003]
  An example of such a light emitting device is a light emitting device as shown in FIG. An LED chip is die-bonded as a light-emitting element on the lead electrode 2 exposed from the inner bottom surface of the recess, using a plastic package 5 having a recess and integrally formed with a lead electrode inserted, and each electrode of the LED chip A lead electrode provided in the package is electrically connected by a gold wire or the like. Thus, the LED chip disposed in the recess is sealed with a light-transmitting member having rigidity after curing. As a result, the LED chip, the wire and the like disposed inside the package can be protected from the external environment such as moisture and external force, and a light emitting device having extremely high reliability can be obtained.
[0004]
  However, such light-emitting devices have begun to be used under more severe environmental conditions due to the expansion of application fields. In a light emitting device used for an aircraft or a vehicle, for example, the temperature may change to −20 ° C. or lower and + 80 ° C. or higher depending on the outside temperature. There is also vibration at the same time as external pressure, thermal shock, and the like. In such a case, each structural member repeats expansion and contraction due to thermal stress, and the structural integrity of each component is weakened. The optical characteristics are adversely affected and the reliability is also lowered. In addition, at the present time when light emitting elements capable of emitting light with high luminance in the near ultraviolet region have been developed and used, it is important to suppress deterioration of each member due to light in the above region.
[0005]
  Therefore, in recent years, a resin having a siloxane bond that is not cleaved by light has attracted attention. Such a resin has excellent light resistance with respect to the wavelength in the above region, and also has high flexibility and high stability to heat.
[0006]
  However, since it has flexibility, its surface is also soft and its mechanical strength is weak, and it is not suitable as an exterior of a light-emitting device. Moreover, since it has tackiness on the surface, foreign matter adheres to it and is not suitable as a light emitting surface.
[0007]
  Japanese Patent Application Laid-Open No. 2000-150968 discloses a light-emitting element mounted on the metal substrate using a package with excellent heat dissipation, and a member having flexibility and excellent light resistance inside the empty wall. A light-emitting device is described which is covered with a rigid cover provided with. The light emitting device configured as described above can have excellent heat resistance, light resistance, and external mechanical strength.
[0008]
[Patent Document 1]
  JP 2000-150968 A
[0009]
[Problems to be solved by the invention]
  However, as described above, when a flexible member is sealed with a rigid member, bubbles tend to be mixed into the flexible member during sealing. In particular, when sealed with a rigid member made of metal or glass that does not pass gas, the flexible member whose thermal stability is impaired by the bubbles cannot relax the thermal stress, and the adjacent rigid member may be damaged. . Further, when bubbles are contained in the interface between the flexible member and the rigid member, these interfaces are peeled off due to the bubbles to form an air layer, resulting in a decrease in light emission output and a change in optical characteristics.
[0010]
  Accordingly, the present invention provides a light-emitting device that solves the above problems and has high reliability and stable optical characteristics.
[0011]
[Means for Solving the Invention]
  A light emitting device of the present invention includes a light emitting element disposed in a recess provided in a package, a first light transmissive member covering the light emitting element, and a first light transmissive member mounted on the first light transmissive member. A second light-transmitting member, wherein the second light-transmitting member has a convex shape protruding in the direction of the light-emitting element, and a flange on the outside of the convex shape. And the flange is disposed in the recess of the package., Covered with the first translucent memberIt is characterized by that.
[0012]
  When the light-emitting element chip is sealed by laminating the first light-transmissive member, which is a flexible member, and the second light-transmissive member, which is a rigid member, bubbles are easily mixed from these interfaces. Light emitting devices with bubbles will lose their integrity due to volatile explosion of bubbles at high temperatures, so reflow mounting that can be soldered to a mounting board etc. at a time cannot be performed, and mass productivity Is scarce. On the other hand, the light emitting device of the present invention has a high reliability that can solve the above-mentioned problem by specifying the shape of the rigid member and can be reflow mounted, and is also compatible with Pb-free mounting. Is possible.
[0013]
  The cross-sectional shape of the back surface is not particularly limited as long as it protrudes in the direction of the light emitting element, but a V-shaped shape that is closest to the light emitting element at one point is preferable because the efficiency of preventing bubble mixing is enhanced.
[0014]
  Furthermore, when the one point is the central portion of the back surface of the second translucent member, it is possible to efficiently prevent air bubbles from being mixed in the entire interface. Moreover, if this back surface is made into a curved surface and a pressure is applied to a flexible member in the back surface which has such a structure, the flow speed of the said flexible member will be accelerated and the bubble defoaming effect can be improved. Accordingly, a highly reliable light-emitting device can be formed with high productivity. Moreover, the adhesiveness with the flexible member below is improved, which is preferable. Further, when the back surface is convex, it is possible to prevent the flexible member from overflowing to the main surface side of the rigid member.
[0015]
  The lower end of the rigid member has a flange that extends outward, and the side surface and the main surface of the flange are covered with the flexible member. By providing the collar portion in this way, the attaching operation of the rigid member is facilitated. Further, the adhesiveness with the flexible member is improved, and the reliability can be enhanced without adversely affecting the optical characteristics.
[0016]
  The concave portion of the package includes at least a first main surface, a second main surface that extends outward above the first main surface, and a third main that extends outward above the second main surface. The flexible member is preferably provided continuously over the first main surface, the second main surface, and the lower end of the rigid member. Thereby, the integrity of each member can be maintained without using a separate adhesive, and a light emitting device with excellent reliability can be obtained. On the other hand, when each member is bonded with a small amount of adhesive or the like, the adhesive or the like is locally deteriorated by heat or light, resulting in a decrease in reliability. The local deterioration is prevented and the life of the light emitting device is extended.
[0017]
  The second main surface is a main surface of at least three or more support bases provided apart from each other on the first main surface, and one back surface of the rigid member is in contact with the second main surface. It is preferable. With such a configuration, even if the rigid member and the flexible member are peeled off when used in a severe environment, the peeled portion can be controlled near the support base, and the optical characteristics can be maintained. .
[0018]
  The rigid member is inscribed with at least three or more contacts in the outline of the second main surface, and the first main surface and the second main surface are respectively in the rigid member. It is preferable to have an exposed part outside between each contact. The light-emitting device configured as described above uses the pressure when the rigid member is placed on the flexible member, and the rigid member positioned with high accuracy by the second main surface and the first main surface Due to the action of the exposed portion of the light emitting device, air bubbles mixed in the flexible member or the interface between the flexible member and the rigid member are discharged to the outside, and a light emitting device having high reliability and stable optical characteristics is made an easy technique with high yield. Can be obtained. In many cases, the surface of the flexible member has a shape in which the central portion has an upward convexity due to surface tension in the applied state before curing, and this convex portion is pressed by one back surface to flow through the package concave portion. Thereby, the bubble defoaming action can be applied to the entire flexible member. The light emitting device of the present invention is integrally formed with the rigid member using a flexible member that overflows during the defoaming action. Moreover, it is preferable that the main surface of a rigid member has a curved surface which protruded on the opposite side to the back surface. The light emitting surface having such a shape can collect the light reflected and scattered by the inner wall of the concave portion and increase the luminance in the front direction. In particular, the back surface having a curved surface protruding in the concave direction as described above is incident on the rigid member in a state where light is diffused. Therefore, a curved surface protruding to the opposite side of the back surface is provided on the main surface side. Is preferably condensed.
[0019]
  Furthermore, the lower end of the rigid member has an eaves portion that extends outward, the side surface and the main surface of the eave portion are covered with the flexible member, and the back surface of the eave portion is connected to the second main surface. It is preferable to be parallel and opposed to each other, whereby the positioning accuracy between the rigid member and the second main surface is improved, and a highly reliable light-emitting device without causing an optical axis shift between the light-emitting devices. It can be provided with good mass productivity.
[0020]
  When the outline of the second main surface is a polygon having more corners than the outline of the rigid member, a small light emitting device capable of high-density mounting is obtained.
[0021]
  If the outline of the rigid member is rounded at the contact point, the speed of overflowing the flexible member to the second main surface is increased, and the rigid member can be quickly fixed. Thereby, the stress which concerns on a flexible member becomes strong, a defoaming effect | action improves and reliability increases. Furthermore, the flexible member provided over the second main surface and the lower end portion of the rigid member becomes a gentle and flat main surface, and a preferable appearance is obtained.
[0022]
  In the first main surface, the exposed portion is preferably a convex portion protruding outward from the central region. By setting it as such a shape, a flexible member can be efficiently flowed to a 2nd main surface and a rigid member lower end part efficiently. Moreover, the defoaming effect | action of a flexible member is improved because a flexible member collides with the said convex part wall surface. When the convex portion faces the corner of the second main surface, a flexible member having a uniform film thickness can be formed on the exposed portion of the second main surface, and structurally integrated. Sexuality can be strengthened. Further, when the tip of the convex portion is rounded, the effect is further increased.
[0023]
  When the package is one in which a pair of lead electrodes is inserted from the side surface and is integrally molded with a molding resin, the inner portion of the lead electrode is along the outline of the first main surface on the first main surface. Are preferably exposed. Since the surface of the lead electrode is a metal, it is considered that the fluidity of the flexible member is excellent. The present invention has a high reliability by causing the flexible member to collide and recoil on each side wall of the package to flow upward, but the lead electrode is arranged along the side wall where the collision recoil is performed. If provided, the impact reaction speed of the flexible member is accelerated, and the effect of the bubble defoaming action is enhanced.
[0024]
  The inner portion of the lead electrode is preferably provided separately from the exposed portion of the first main surface in two inner directions, thereby further improving the above effects. Also, the integrally formed lead electrode is prevented from coming off. In addition, when it is necessary to place another element such as a protective element, the element is placed at a position that does not participate in the light emission observation plane when it is electrically connected by being placed between the separate branch leads. Is preferable.
[0025]
  It is preferable that a part of the back surface of the inner part of the lead electrode is exposed from a minute hole penetrating from the back side of the package. Thereby, the stress of the lead electrode received when wire bonding is performed or when the rigid member is placed can be relieved. Thereby, structural integration of a lead electrode and each member can be strengthened.
[0026]
  Preferably, the package has a metal substrate whose back surface is a mounting surface, the main surface of the metal substrate is exposed from the bottom surface of the recess, and the light emitting element is mounted on the metal substrate. Thereby, heat generated from the light emitting element can be radiated to the mounting substrate satisfactorily, and the reliability of the flexible member covering the light emitting element can be improved. In addition, the fluidity of the lower flexible member can be improved on the surface of the metal substrate, and local deterioration in the vicinity of the light emitting element can be prevented.
[0027]
  It is preferable that the metal substrate is inserted from the side surface direction and integrally formed with the lead electrode with the molding resin, and one end portion projects from the side surface of the package. Thereby, the contact area with the external air of a metal base | substrate increases, and the heat dissipation of a light-emitting device can be improved.
[0028]
  The metal substrate preferably has a first main surface exposed from the recess and a second main surface buried in the package. This improves the structural integrity of the light emitting device.
[0029]
  It is preferable to provide a second recess at the center of the main surface of the metal base exposed from the bottom surface of the recess, and place the light emitting element on the bottom surface of the second recess. This improves the extraction efficiency of light emitted from the end face of the light emitting element, prevents bubbles from entering the flexible member, defoams the mixed bubbles, and provides flexibility in the vicinity of the light emitting element when using the light emitting device. The fluidity of the adhesive member is also improved. In addition, the contact area between the flexible member and the metal substrate serving as the heat dissipation path is increased, and local deterioration of the flexible member can be prevented.
[0030]
  One end of the pair of lead electrodes is preferably exposed in parallel at a predetermined distance from the side opposite to the side where the one end of the metal substrate is exposed. Thereby, the electrode wiring of the mounting substrate can be simplified. In addition, the light emitting device can be reduced in size while maintaining the back surface area of the metal substrate. Further, by providing a notch portion on the opposite side surface side on the back surface of the package, even if there are too many conductive members provided on the back surface of the metal base, the notch that the conductive member flows out in the lead electrode direction. Therefore, it is possible to prevent the lead electrode from flowing out to the opposite lead electrode and improve the yield.
[0031]
  When the light emitting element has a pair of positive and negative electrodes on the same plane side, and the pair of positive and negative electrodes are respectively bridged with the inner part of the pair of lead electrodes by a wire, the vertex of the wire is the first main electrode. It is preferable to arrange | position between a surface and said 2nd main surface. By providing the wire in this way, the fluidity of the flexible member can be improved and the influence of thermal stress on the wire can be minimized. In addition, since the lead electrode is disposed above each electrode of the light emitting element and there is no obstacle protruding upward at the wire passing point from the light emitting element to the lead electrode, the wire bonding operation is relatively easy and reliable. It can be done with high performance.
[0032]
  The flexible member may contain a fluorescent material. When the flexible member is configured by a laminated structure including at least two layers, the fluorescent material may be contained in at least one layer. That's fine.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
  As a result of various experiments, the present inventor has found that the above problem can be solved by specifying the shape of the rigid member member when the light emitting element chip is covered with the flexible member and the rigid member. Invented the invention. Hereafter, each structure of this invention is explained in full detail.
[0034]
  (Package 1)
  For example, as shown in FIG. 1, the package has a positive lead electrode, a negative lead electrode 5, and a metal base that becomes a heat sink, inserted into the molds that are inserted from opposite sides and closed, on the lower surface side. It is formed by pouring molten resin from a certain gate and curing it.
[0035]
  More specifically, the package has a first recess on the main surface side, and the main surface of the metal base 6 inserted from one side surface of the package is exposed from the bottom surface of the recess. The main surface of the metal base 6 is provided with a second recess capable of accommodating a light emitting element.
[0036]
  On the other hand, a first main surface extending outwardly above the first concave portion and a second main surface extending outwardly above the first main surface are provided. The main surfaces of the pair of positive and negative lead electrodes inserted from the other side surface facing the one side surface of the package are exposed from the first main surface. The main surface of the lead electrode is electrically connected to each electrode of the light emitting element by a wire. The second main surface serves to position a rigid member placed on the upper side.
[0037]
  Using a package having such a configuration, a light emitting element is electrically connected to the bottom surface of the recess of the package, and these are used as a flexible member as a first sealing member and a rigid member as a second sealing member. And sealed to obtain the light emitting device of the present invention.
[0038]
  Here, it is sufficient that the lead electrode main surface exposed at the first recess has an area necessary for fixing a conductive wire to be cross-linked with each electrode of the light emitting element chip as shown in FIG. Other lead electrode main surfaces are preferably covered with the same material as the package resin. Thereby, the vaporization expansion which arises in the interface of a lead electrode and a 1st sealing member can be suppressed. Further, by increasing the contact area between the package molding resin having relatively high adhesiveness and the sealing member, the light emitting device can be integrated and a light emitting device with high optical characteristics and reliability can be obtained.
[0039]
  Here, the package of the present embodiment has a shape that allows the first main surface and a part of the second main surface to be exposed to the outside from the second sealing member. In the present embodiment, the outer wall of the second main surface is a rounded square, a second sealing member whose outer shape is a circle is inscribed in the square, and the outer periphery of the second sealing member At four places, both the edge of the second main surface and the edge of the first main surface are exposed. As described above, the present invention provides a consistent passage from the bottom surface of the package to the upper side without being blocked by the rigid member when the rigid member is placed on the upper side after sealing the flexible member inside the package. Bubbles are also pushed out together with the flexible member from the passage, and bubbles can be prevented from being mixed between the rigid member and the flexible member. Particularly in the present embodiment, the exposed portion of the first main surface is a convex shape protruding from the central portion of the first main surface, so that the bubble defoaming effect due to the collision reaction by the outer contour of the convex shape Has improved. In the present embodiment, such a consistent passage is formed by adjusting the form of the package, but the present invention is not limited to this, and it can also be formed by forming a notch at the edge of the lens.
[0040]
  (Lead electrode 5)
  The lead electrode can be configured using a high thermal conductor such as copper or iron-containing copper. In addition, in order to improve the reflectance of light from the light emitting element and to prevent oxidation of the lead base material, the surface of the lead electrode can be subjected to metal plating such as silver, aluminum, copper or gold. In order to improve the reflectance of the surface, smoothing is preferable. In addition, it is preferable to increase the area of the lead electrode. In this way, heat dissipation can be improved, and the temperature rise of the light emitting element chip to be arranged can be effectively suppressed. Accordingly, a relatively large amount of power can be input to the light emitting element chip, and the light output can be improved.
[0041]
  The lead electrode is formed, for example, by punching a long metal plate made of a copper alloy metal having a thickness of 0.15 mm. In the present embodiment, the press working is performed so that the positive lead electrode and the negative lead electrode are connected in one direction.
[0042]
  In the light emitting device of the present invention, it is preferable that the angle between the back surface and the side surface of the lead electrode is curved. As described above, when the end of the lead electrode is rounded in accordance with the direction of injecting the resin, the flow of the molding resin becomes smooth, and the adhesion between the lead electrode and the molding resin portion is enhanced. Further, the resin can be filled in the space between the pair of lead electrodes exposed on the bottom surface of the package without any gap. Further, the joining line with the lead electrode of the molded resin portion has a shape corresponding to the lead electrode. Therefore, when the lead electrode having the above-described shape is used, the joining line with the back surface on the side surface of the molded resin portion can have a concave shape with a curved base angle. Thereby, stress concentration in the joining line can be avoided and generation of package cracks can be suppressed.
[0043]
  Furthermore, it is preferable that the angle between the main surface and the side surface of the lead electrode rises to an acute angle. Thereby, the adhesiveness of a lead electrode and a 1st sealing member is improved, and peeling at these interfaces can be suppressed.
[0044]
  In addition, the outer lead part of the positive lead electrode and negative lead electrode protruding from the outer wall of the package molded body is processed into a gull wing type so that the back surface is flush with the back surface of the molded resin portion and the back surface of the metal substrate. It is a positive and negative connection terminal portion. In addition, the structure of the connection terminal part of this invention is not restricted to a gull wing type | mold, Other structures, such as J-bend (Bend), may be sufficient.
[0045]
  (Metal base 6)
  The package used for the light-emitting device of this embodiment has a metal substrate in the center that can accommodate the light-emitting element and can efficiently dissipate heat generated from the light-emitting element. The metal base has a recess on the main surface side, and the back surface is located on substantially the same plane as the mounting surface of the light emitting device, that is, the back surface of the connecting terminal portion of the lead electrode and the back surface of the molded resin portion, It is configured to touch. With this configuration, heat generated from the light emitting element can be directly radiated to the mounting substrate, and the amount of current dropped on the light emitting element can be increased to improve output. The film thickness of the bottom surface of the recess is formed in a thin film so as to have good heat dissipation. The concave portion is preferably located in the central portion of the light emitting device, whereby good directivity characteristics can be obtained. Moreover, it is preferable that a recessed part has a volume which can accommodate the said light emitting element whole. Thereby, the light emitted from the four side surfaces of the light emitting element can be favorably extracted in the front direction through the inner wall of the recess. In addition, when the wavelength of the light emitting element is converted using the color conversion layer, the entire light emitting element arranged in the concave portion can be easily covered with the color conversion layer. The color conversion layer includes a translucent member and a fluorescent material capable of absorbing a part of light emitted from the light emitting element and emitting other wavelengths. Since the metal package used in the present invention is particularly excellent in heat dissipation of the concave portion in which the light emitting element is disposed, each member of the color conversion layer is not limited to an inorganic material, and an organic material can be used. The organic matter hardly deteriorates due to the above, and good optical characteristics can be obtained. Moreover, it is preferable that the inner wall of the said recessed part is a taper shape so that a volume may become so large that it goes to the opening side, and, thereby, the light-emitting device which can light-emit with higher brightness | luminance is obtained.
[0046]
  The concave portion is formed by, for example, drawing a metal flat plate. In the present embodiment, the metal plate is drawn from the main surface direction of the metal flat plate to flow the metal in the back surface direction to form the recess. As a result, the outer shell of the back surface has an uneven shape, the contact area with the molded resin portion is increased, and the structural integrity can be enhanced.
[0047]
  The thermal conductivity of the lead electrode and the metal substrate is preferably in the range of 10 W / m · K to 100 W / m · K, more preferably 15 W / m · K to 80 W / m · K, further Preferably, it is 15 W / m · K or more and 50 W / m · K or less. A light emitting device capable of supplying a large current for a long time while maintaining reliability can be obtained.
[0048]
  (Light emitting element 2)
  The light-emitting element chip used in the present invention is not particularly limited. However, when the pair of lead electrodes and the metal substrate are insert-molded with a molding resin as described above, the light-emitting element has a pair of positive and negative electrodes on the same surface side. A chip is used. In addition, when a fluorescent material is used, a semiconductor light emitting element having a light emitting layer capable of emitting an emission wavelength capable of exciting the fluorescent material is preferable. Examples of such semiconductor light emitting devices include various semiconductors such as ZnSe and GaN, but nitride semiconductors (In_XAl_YGa_1-XYN, 0 ≦ X, 0 ≦ Y, and X + Y ≦ 1) are preferable. If desired, the nitride semiconductor may contain boron or phosphorus. Examples of the semiconductor structure include a homostructure having a MIS junction, a PIN junction, and a pn junction, a heterostructure, and a double heterostructure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal. In addition, a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed in a thin film in which a quantum effect is generated can be used. When a nitride semiconductor is used, materials such as sapphire, spinel, SiC, Si, ZnO, and GaN are preferably used for the semiconductor substrate. In order to form a nitride semiconductor with good crystallinity with high productivity, it is preferable to use a sapphire substrate. A nitride semiconductor can be formed on the sapphire substrate by MOCVD or the like. A buffer layer of GaN, AlN, GaAIN or the like is formed on the sapphire substrate, and a nitride semiconductor having a pn junction is formed thereon. As an example of a light emitting device having a pn junction using a nitride semiconductor, a first contact layer formed of n-type gallium nitride, a first cladding layer formed of n-type aluminum nitride / gallium, and a nitride layer on a buffer layer Examples include a double hetero structure in which an active layer formed of indium gallium, a second cladding layer formed of p-type aluminum nitride / gallium, and a second contact layer formed of p-type gallium nitride are sequentially stacked. Nitride semiconductors exhibit n-type conductivity without being doped with impurities. When forming a desired n-type nitride semiconductor, for example, to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, etc. as an n-type dopant. On the other hand, when forming a p-type nitride semiconductor, the p-type dopants such as Zn, Mg, Be, Ca, Sr, and Ba are doped. Since nitride semiconductors are not easily converted to p-type by simply doping with a p-type dopant, it is preferable to reduce resistance by heating in a furnace or plasma irradiation after introducing the p-type dopant. The semiconductor substrate may be removed after laminating a metal layer on the p-type layer. When the thus configured light emitting element is mounted such that the metal layer is on the mounting surface side, a light emitting device with high heat dissipation can be obtained. A light emitting element made of a nitride semiconductor can be formed by forming each electrode on the exposed p-type layer and n-type layer and then cutting the semiconductor wafer into chips.
[0049]
  In the light emitting diode of the present invention, in order to emit white light, the emission wavelength of the light emitting element is preferably 400 nm or more and 530 nm or less in consideration of the complementary color relationship with the emission wavelength from the fluorescent material, deterioration of the translucent resin, and the like. 420 nm or more and 490 nm or less is more preferable. In order to further improve the excitation and emission efficiency of the light emitting element and the fluorescent material, 450 nm or more and 475 nm or less are more preferable.
[0050]
  In the present invention, since the light emitting element chip is sealed with high reliability by the first sealing member having excellent light resistance and flexibility, local deterioration of the component due to near ultraviolet rays or ultraviolet rays is suppressed. be able to. Therefore, the light-emitting device of the present invention uses a light-emitting element whose main emission wavelength is an ultraviolet region shorter than 400 nm, a fluorescent substance capable of absorbing part of light from the light-emitting element and emitting other wavelengths. By combining these, a color conversion light emitting device with little color unevenness can be obtained. Here, when the fluorescent substance is bound to the light emitting element chip, it is preferable to use a resin that is relatively resistant to ultraviolet rays, an inorganic glass, or the like.
[0051]
  Here, the light emitting element is, for example, a gallium nitride compound semiconductor element capable of emitting blue light, and the element includes, for example, a nitride semiconductor layer including an n-type layer, an active layer, and a p-type layer on a sapphire substrate. An n electrode is formed on the n-type layer formed and exposed by removing a part of the active layer and the p-type layer, and a p-electrode is formed on the p-type layer.
[0052]
  (Flexible member 3)
  A flexible member is provided so as to cover the light emitting element from the inside of the recess of the package to the lower end of the upper rigid member. In addition to protecting the light emitting element from moisture and the like, the flexible member has translucency and can efficiently extract light from the light emitting element to the outside. Moreover, since it has high stability with respect to heat, it is possible to relieve thermal stress generated during operation of the light emitting device. Further, when a light emitting element in the near ultraviolet region or the ultraviolet region is used, it is preferable to use a flexible member having excellent light resistance against these lights. Examples of these flexible members include rubber-like elastic resins and gel-like resins. Since these resins have a low crosslinking density or do not have a crosslinked structure, they can have good flexibility. In addition, a coloring dye or a coloring pigment can be added to give a specific filter effect to the light from the light emitting element chip.
[0053]
  (Rigid member 4)
  In the light emitting device of the present invention, the flexible member provided around the light emitting element is sealed with a rigid member. The rigid member used in the present invention is not particularly limited as long as it has mechanical strength and is translucent.
[0054]
  In the present embodiment, the rigid member that is the light extraction window is located on the upper surface of the light emitting element disposed in the recess of the metal package, and the inside of the extension line of the inner wall of the recess and the intersection emits light. Will be involved in the face. The light emitted from the end of the light emitting element is reflected and scattered by the side surface of the recess in the flexible member, passes through the rigid member, and is extracted in the front direction. It is considered that the range in which these reflected scattered light exists is substantially within the extension line of the side surface of the recess. Therefore, a light emitting device capable of emitting desired luminance can be obtained by adjusting the shape inside the intersection to any shape. Moreover, it is preferable that the base material of the rigid member has a thermal expansion coefficient approximate to that of the molding resin forming the package body and the flexible member provided in the lower part.
[0055]
  The shape of the rigid member preferably has one continuous back surface. Thereby, it becomes possible to install with high reliability without air bubbles being mixed into the interface with the flexible member. Moreover, if an edge is provided on the outer periphery of the back surface, it can be installed more reliably. The edge portion is preferably provided outside the extended line of the side surface of the concave portion in which the light emitting element is accommodated, and this makes it possible to improve the reliability without affecting the optical characteristics. On the other hand, it is preferable that the main surface side has a curved surface with a central portion protruding inside the extension line of the side surface of the recess. Thereby, the light diffused on the back side can be efficiently converged in the front direction, and the luminous intensity in the front direction can be increased. In the present invention, the rigid member is structurally integrated with each member by a flexible member that is inscribed in the outline of the second main surface and overflows through a consistent passage from the bottom surface of the recess to the main surface side. Yes. In such a rigid member, a coloring dye or a coloring pigment can be added to give a specific filter effect or the like to the light from the light emitting element chip on the inside, the main surface side surface, and the back surface side.
[0056]
  (Fluorescent substance 8)
  In the present invention, the flexible member and the rigid member may contain other substances such as the fluorescent substance 8. Here, the fluorescent substance used in the present embodiment will be described in detail.
[0057]
  In the present invention, various fluorescent materials such as an inorganic fluorescent material and an organic fluorescent material can be contained in each constituent member. As an example of such a fluorescent substance, there is a phosphor containing a rare earth element which is an inorganic phosphor. As the rare earth element-containing phosphor, specifically, at least one element selected from the group of Y, Lu, Sc, La, Gd, and Sm, and at least one selected from the group of Al, Ga, and In And a garnet-type phosphor having an element. In particular, yttrium-aluminum oxide phosphors activated with cerium are preferable, and in addition to Ce, Tb, Cu, Ag, Au, Fe, Cr, Nd, Dy, Ni, Ti, Eu, and Pr may be used as desired. Etc. can also be contained.
[0058]
  In the light-emitting device of this example, fluorescence based on a cerium-activated yttrium-aluminum oxide-based fluorescent material that can emit light by exciting light emitted from a semiconductor light-emitting element having a nitride-based semiconductor as a light-emitting layer. The substance is used.
[0059]
  As a specific yttrium / aluminum oxide fluorescent material, YAlO₃: Ce, Y₃Al₅O₁₂: Ce (YAG: Ce) or Y₄Al₂O₉: Ce, and also a mixture thereof. The yttrium / aluminum oxide phosphor may contain at least one of Ba, Sr, Mg, Ca, and Zn. Moreover, by containing Si, the reaction of crystal growth can be suppressed and the particles of the fluorescent material can be aligned.
[0060]
  In this specification, the yttrium / aluminum oxide phosphor activated by Ce is to be interpreted in a broad sense, and a part or all of yttrium is selected from the group consisting of Lu, Sc, La, Gd and Sm. Or a part or all of aluminum is used in a broad sense including a phosphor having a fluorescent action in which any one or both of Ba, Tl, Ga, and In are substituted.
[0061]
  More specifically, the general formula (Y_zGd_1-z)_ThreeAl_FiveO₁₂: Photoluminescence phosphor represented by Ce (where 0 <z ≦ 1) or a general formula (Re_1-aSm_a)_ThreeRe ’_FiveO₁₂: Ce (where 0 ≦ a <1, 0 ≦ b ≦ 1, Re is at least one selected from Y, Gd, La, Sc, and Re ′ is at least one selected from Al, Ga, In) The photoluminescence phosphor shown in FIG.
[0062]
  Since this fluorescent material has a garnet structure (garnet-type structure), it is resistant to heat, light and moisture, and the peak of the excitation spectrum can be made around 450 nm. The emission peak is also in the vicinity of 580 nm and has a broad emission spectrum that extends to 700 nm.
[0063]
  Further, the photoluminescence phosphor can increase the excitation light emission efficiency in a long wavelength region of 460 nm or more by containing Gd (gadolinium) in the crystal. As the Gd content increases, the emission peak wavelength shifts to a longer wavelength, and the entire emission wavelength also shifts to the longer wavelength side. That is, when a strong reddish emission color is required, it can be achieved by increasing the amount of Gd substitution. On the other hand, as Gd increases, the emission luminance of photoluminescence by blue light tends to decrease. Furthermore, in addition to Ce, Tb, Cu, Ag, Au, Fe, Cr, Nd, Dy, Co, Ni, Ti, Eu, and the like can be contained as desired.
[0064]
  Moreover, in the composition of the yttrium / aluminum / garnet (garnet) phosphor having a garnet structure, the emission wavelength is shifted to the short wavelength side by substituting part of Al with Ga. Further, by substituting part of Y in the composition with Gd, the emission wavelength is shifted to the longer wavelength side.
[0065]
  When substituting a part of Y with Gd, it is preferable that the substitution with Gd is less than 10%, and the Ce content (substitution) is 0.03 to 1.0. If the substitution with Gd is less than 20%, the green component is large and the red component is small. However, by increasing the Ce content, the red component can be supplemented and a desired color tone can be obtained without lowering the luminance. With such a composition, the temperature characteristics are good and the reliability of the light emitting diode can be improved. In addition, when a photoluminescent phosphor adjusted to have a large amount of red component is used, a light emitting device capable of emitting an intermediate color such as pink can be formed.
[0066]
  Such photoluminescent phosphors use oxides or compounds that easily become oxides at high temperatures as raw materials for Y, Gd, Al, and Ce, and mix them well in a stoichiometric ratio. Get raw materials. Alternatively, a mixed raw material obtained by mixing a coprecipitation oxide obtained by firing a solution obtained by coprecipitation of a solution obtained by dissolving a rare earth element of Y, Gd, and Ce in an acid in a stoichiometric ratio with oxalic acid and aluminum oxide. Get. A suitable amount of fluoride such as barium fluoride or ammonium fluoride is mixed as a flux and packed in a crucible, and fired in air at a temperature range of 1350 to 1450 ° C. for 2 to 5 hours to obtain a fired product, and then fired. The product can be obtained by ball milling in water, washing, separating, drying and finally passing through a sieve.
[0067]
  In the light emitting device of the present invention, such a photoluminescent phosphor may be a mixture of yttrium, aluminum, garnet (garnet type) phosphor activated with two or more kinds of cerium, and other phosphors. .
[0068]
  The particle size of the fluorescent material used in the present invention is preferably in the range of 10 μm to 50 μm, more preferably 15 μm to 30 μm. A fluorescent material having a particle size of less than 15 μm is relatively easy to form an aggregate, and is densely settled in a liquid resin, thus reducing the light transmission efficiency. In the present invention, by using such a fluorescent material that does not have a fluorescent material, concealment of light by the fluorescent material is suppressed and the output of the light emitting device is improved. In addition, the fluorescent material having a particle size range of the present invention has high light absorption and conversion efficiency and a wide excitation wavelength range. Thus, by including a large particle size fluorescent material having optically excellent characteristics, light around the dominant wavelength of the light emitting element can be converted and emitted well, and the mass productivity of the light emitting device is improved. Is done.
[0069]
  Here, in the present invention, the particle size is a value obtained from a volume-based particle size distribution curve. The volume-based particle size distribution curve is obtained by measuring the particle size distribution by a laser diffraction / scattering method. Specifically, in an environment of an air temperature of 25 ° C. and a humidity of 70%, hexametalin having a concentration of 0.05%. Each substance was dispersed in an aqueous sodium acid solution and measured with a laser diffraction particle size distribution analyzer (SALD-2000A) in a particle size range of 0.03 μm to 700 μm. In this volume-based particle size distribution curve, it is a particle size value when the integrated value is 50%, and the central particle size of the fluorescent material used in the present invention is preferably in the range of 15 μm to 50 μm. Moreover, it is preferable that the fluorescent substance which has this center particle size value is contained frequently, and the frequency value is preferably 20% to 50%. In this way, by using a fluorescent material with small variation in particle size, a light emitting device having a favorable color tone with suppressed color unevenness can be obtained.
[0070]
  The location of the fluorescent material is not particularly limited, and a binder may be provided on the back surface of the window portion of the rigid member, or may be directly contained in each material of the rigid member and the flexible member. When the fluorescent material is attached to the back surface of the rigid member or the surface of the light emitting element with a binder, the material of the binder is not particularly limited, and either an organic material or an inorganic material can be used. When an organic substance is used as the binder, a transparent resin excellent in weather resistance such as an epoxy resin, an acrylic resin, or silicone is preferably used as a specific material. In particular, silicone is preferable because it is excellent in reliability and can improve the dispersibility of the fluorescent material.
[0071]
  In addition, when a fluorescent substance is placed on the lens surface, it is preferable to use an inorganic substance that is close to the coefficient of thermal expansion as a binder because the fluorescent substance can be satisfactorily adhered. As a specific method, a precipitation method, a sol-gel method, or the like can be used. For example, fluorescent material, silanol (Si (OEt)₃OH) and ethanol are mixed to form a slurry. After the slurry is discharged from the nozzle to the window of the rigid member, the slurry is heated at 300 ° C. for 3 hours to convert silanol into SiO 2.₂And the fluorescent material can be fixed.
[0072]
  Further, an inorganic binder can be used as a binder. The binder is a so-called low-melting glass, is a fine particle and is preferably very stable in the binder with little absorption with respect to radiation from the ultraviolet to the visible region, and was obtained by a precipitation method. Alkaline earth borates, which are fine particles, are suitable.
[0073]
  In addition, when attaching a fluorescent substance having a large particle size, a binder whose particle is an ultrafine powder even if the melting point is high, such as silica, alumina made by Degussa, or a fine particle size alkali obtained by a precipitation method It is preferred to use earth metal pyrophosphates, orthophosphates and the like. These binders can be used alone or mixed with each other.
[0074]
  Here, a method for applying the binder will be described. In order to sufficiently enhance the binding effect, the binder is preferably used as a binder slurry by wet pulverization in a vehicle to form a slurry. The vehicle is a high viscosity solution obtained by dissolving a small amount of a binder in an organic solvent or deionized water. For example, an organic vehicle can be obtained by adding 1 wt% of nitrocellulose as a binder to butyl acetate as an organic solvent.
[0075]
  A fluorescent substance is contained in the binder slurry thus obtained to prepare a coating solution. The amount of the slurry in the coating solution is preferably such that the total amount of the binder in the slurry is about 1 to 3% wt with respect to the amount of the fluorescent substance in the coating solution. If the amount of the binder added is too large, the luminous flux maintenance factor tends to decrease. Therefore, it is preferable to minimize the amount of use.
[0076]
  When it is desired to fix the fluorescent material to the back surface or the main surface of the rigid member with the binder, the coating liquid is applied to the back surface of the window portion, and then hot air or hot air is blown and dried. Finally, baking is performed at a temperature of 400 ° C. to 700 ° C. to scatter the vehicle. Thereby, the phosphor layer is adhered to the surface of the window portion with the binder.
[0077]
  (Diffusion agent)
  Further, in the present invention, the color conversion member may contain a diffusing agent in addition to the fluorescent material. As a specific diffusing agent, barium titanate, titanium oxide, aluminum oxide, silicon oxide or the like is preferably used. As a result, a light emitting device having good directivity can be obtained.
[0078]
  Here, in this specification, the diffusing agent refers to those having a center particle diameter of 1 nm or more and less than 5 μm. A diffusing agent having a size of 1 μm or more and less than 5 μm is preferable because it diffuses light from the light-emitting element and the fluorescent material well and can suppress color unevenness that tends to occur by using a fluorescent material having a large particle size. In addition, the half width of the emission spectrum can be narrowed, and a light emitting device with high color purity can be obtained. On the other hand, a diffusing agent having a wavelength of 1 nm or more and less than 1 μm has a low interference effect on the light wavelength from the light emitting element, but has a high transparency and can increase the resin viscosity without reducing the luminous intensity. As a result, when the color conversion member is arranged by potting or the like, it becomes possible to disperse the fluorescent substance in the resin almost uniformly in the syringe and maintain the state, and the fluorescent substance having a large particle size that is relatively difficult to handle. Even when a substance is used, it is possible to produce with good yield. Thus, the action of the diffusing agent in the present invention varies depending on the particle size range, and can be selected or combined according to the method of use.
[0079]
  (Filler)
  Furthermore, in the present invention, the color conversion member may contain a filler in addition to the fluorescent material. The specific material is the same as that of the diffusing agent, but the diffusing agent has a central particle size different from that of the diffusing agent. In this specification, the filler has a central particle size of 5 μm or more and 100 μm or less. When the filler having such a particle size is contained in the translucent resin, the chromaticity variation of the light emitting device is improved by the light scattering action, and the thermal shock resistance of the translucent resin can be enhanced. As a result, even when used at high temperatures, it is possible to prevent disconnection of the wire that electrically connects the light emitting element and the external electrode, and peeling of the bottom surface of the light emitting element and the bottom surface of the recess of the package with high reliability. A light emitting device is obtained. Furthermore, the fluidity of the resin can be adjusted to be constant for a long time, and a sealing member can be formed in a desired place, and mass production can be performed with a high yield.
[0080]
  The filler preferably has a particle size and / or shape similar to that of the fluorescent material. Here, in this specification, the similar particle diameter means a case where the difference in the central particle diameter of each particle is less than 20%, and the similar shape means an approximate degree of each particle diameter with a perfect circle. This represents a case where the difference in the value of the degree of circularity (circularity = perimeter length of a perfect circle equal to the projected area of the particle / perimeter length of the projected particle) is less than 20%. By using such a filler, the fluorescent material and the filler interact with each other, and the fluorescent material can be favorably dispersed in the resin, thereby suppressing color unevenness. Furthermore, it is preferable that both the fluorescent substance and the filler have a central particle diameter of 15 μm to 50 μm, more preferably 20 μm to 50 μm. In this way, by adjusting the particle diameter, a preferable interval is provided between the particles. be able to. As a result, a light extraction path is ensured, and the directivity can be improved while suppressing a decrease in luminous intensity due to filler mixing.
[0081]
  Hereinafter, the light-emitting device of the Example which concerns on this invention is explained in full detail. In addition, this invention is not limited only to the Example shown below.
【Example】
[0082]
  Example 1
  A surface mount type light emitting device as shown in FIG. 1 is formed. The LED chip has a 475 nm In as a light emitting layer with a monochromatic emission peak of visible light._0.2Ga_0.8A nitride semiconductor element having an N semiconductor is used. More specifically, in the LED chip, TMG (trimethyl gallium) gas, TMI (trimethyl indium) gas, nitrogen gas and dopant gas are flowed together with a carrier gas on a cleaned sapphire substrate, and a nitride semiconductor is formed by MOCVD. Can be formed. SiH as dopant gas₄And Cp₂A layer to be an n-type nitride semiconductor or a p-type nitride semiconductor is formed by switching Mg.
[0083]
  As an element structure of the LED chip, an n-type GaN layer which is an undoped nitride semiconductor on a sapphire substrate, a GaN layer where an Si-doped n-type electrode is formed to become an n-type contact layer, and an n-type nitride semiconductor which is an undoped nitride semiconductor 5 layers of InGaN layers sandwiched between GaN layers, each comprising a type GaN layer, a GaN layer that constitutes a light emitting layer, a InGaN layer that constitutes a well layer, and a GaN layer that constitutes a barrier layer It is a multiple quantum well structure. On the light emitting layer, an AlGaN layer as a p-type cladding layer doped with Mg and a GaN layer as a p-type contact layer doped with Mg are sequentially laminated. (Note that a GaN layer is formed on the sapphire substrate at a low temperature to serve as a buffer layer. The p-type semiconductor is annealed at 400 ° C. or higher after film formation.)
[0084]
  Etching exposes the surface of each pn contact layer on the same side as the nitride semiconductor on the sapphire substrate. Positive and negative pedestal electrodes are formed on each contact layer by sputtering. A metal thin film is formed on the entire surface of the p-type nitride semiconductor as a translucent electrode, and then a pedestal electrode is formed on a part of the translucent electrode. After drawing the scribe line on the completed semiconductor wafer, it is divided by an external force to form LED chips that are semiconductor light emitting elements.
[0085]
  On the other hand, a first copper plate having a thickness of 0.3 mm is punched to form a plurality of pairs of lead electrodes connected in one direction. Next, a 1.2 mm-thick second copper plate having a thickness greater than that of the first copper plate is punched and pressed, and a metal substrate having a recess capable of accommodating a light emitting element chip on the main surface side is provided. A plurality are formed. The pair of lead electrodes and the metal base are inserted from opposite directions, and are arranged in a metal mold so that the respective lead electrodes are symmetrical via the metal base above the metal base. At this time, the inner tip portion of each lead electrode is fixed by the support from below.
[0086]
  In this way, the first copper plate and the second copper plate installed in the mold are integrally formed with a molding resin to create a package. The package thus obtained has a first concave portion in which the concave portion of the metal substrate is exposed on the main surface side, a first main surface that spreads outward above the first concave portion, and the first main surface. A second main surface extending outwardly above the surface. The outline of the second main surface is a square with a rounded corner, and the corners of the first main surface are provided with protrusions toward the corners of the second main surface. The protrusion is configured to be exposed to the outside of the rigid member when the rigid member is placed on the upper side.
[0087]
  Next, an LED chip is die-bonded with an Ag—Sn alloy in a recess provided in the metal substrate. Here, as the bonding member used for die bonding, a resin or glass containing a conductive material can be used in addition to the above-described alloy. The conductive material contained is preferably Ag. When an Ag paste having a content of 80% to 90% is used, a light emitting device having excellent heat dissipation and low stress after bonding can be obtained. In addition, it is preferable to provide a metal layer on the substrate side of the light-emitting element and fix the light-emitting element because heat dissipation and light extraction efficiency are improved.
[0088]
  Next, the respective electrodes of the die-bonded LED chip and the respective lead electrodes exposed from the bottom of the package recess are electrically connected by Ag wires. Here, when resin is not used for the constituent members, it is also possible to use Al wires.
[0089]
  Next, a gel-like silicone resin is injected by potting so as to cover the second main surface from the concave portion, and then a glass lens as a light-transmitting rigid member is pressed downward onto the gel-like silicone resin. Place. Here, the lens can be made of a thermoplastic resin, glass, or the like, which is a plastic. Moreover, it has one continuous back surface and has a curved surface protruding downward. Further, the outer peripheral portion has an edge portion whose rear surface is parallel to the second main surface. Further, the outer shell of the edge portion has a circular shape so as to be inscribed in the outer shell of the second main surface. The lens configured as described above is installed on the second main surface, and a part of the gel-like silicone resin below the protruding portion of the first main surface exposed from the outside of the lens is After overflowing to the upper surface of the edge, heating is performed at 70 ° C. for 2 hours, at 100 ° C. for 2 hours, and further at 150 ° C. for 2 hours to structurally integrate the members.
[0090]
  The light-emitting device obtained in this manner does not have contaminants such as bubbles and has excellent reliability and optical characteristics.
[0091]
  (Example 2)
  As shown in FIG. 10, when the light emitting device is formed in the same manner as in Example 1 except that the outline of the second main surface is a rounded hexagon, it is more mass-productive and denser than Example 1. A light-emitting device that can be obtained is obtained.
[0092]
  (Example 3)
  As shown in FIG. 11, the outline of the second main surface and the outline of the first main surface are polygons that are similar to each other, and the lens has an outer periphery so that the corners of the first main surface are exposed. When the light emitting device is formed in the same manner as in Example 1 except that the portion has a notch, the same effect as in Example 1 can be obtained.
[0093]
  (Example 4)
  When the light emitting device is formed in the same manner as in Example 3 except that the lens used as the rigid member has a convex lens shape, the front luminous intensity is improved by 50% compared to Example 1.
[0094]
  (Example 5)
  A light emitting device is formed in the same manner as in Example 1 except that a fluorescent material is previously contained in the lens.
[0095]
  Here, as the fluorescent material, a solution obtained by dissolving rare earth elements of Y, Gd, and Ce in acid at a stoichiometric ratio is coprecipitated with oxalic acid. A co-precipitated oxide obtained by firing this and aluminum oxide are mixed to obtain a mixed raw material. This is mixed with barium fluoride as a flux and packed in a crucible and fired in air at a temperature of 1400 ° C. for 3 hours to obtain a fired product. The fired product is ball-milled in water, washed, separated, dried, and finally passed through a sieve to have a center particle size of 22 μm (Y_0.995Gd_0.005)_2.750Al₅O₁₂: Ce_0.250Form a fluorescent material.
[0096]
  The fluorescent substance thus obtained and powdered silica are mixed at a ratio of 1: 2, and melt-cured in a mold and collectively molded. The color conversion type light-emitting device obtained in this way can achieve the same effects as those of Example 1, and can emit white light with high reliability and high output.
[0097]
  (Example 6)
  A color conversion member is constituted by containing 50 wt% of the fluorescent material in a slurry composed of 90 wt% of nitrocellulose and 10 wt% of γ-alumina, coating the back surface of the rigid member, and heating and curing at 220 ° C. for 30 minutes. Except for the above, when the light emitting device is formed in the same manner as in Example 5, the same effect as in Example 5 is obtained.
[0098]
  (Example 7)
  When the light emitting device is formed in the same manner as in Example 1 except that the elastic silicone resin is applied on the gel silicone resin and then the lens is placed, the adhesion of the lens is improved. A light emitting device with higher reliability than 1 can be obtained.
[0099]
  (Example 8)
  When the light emitting device is formed in the same manner as in Example 7 except that the gel-like silicone resin contains 50 wt% of the fluorescent material, the same effect as in Example 5 can be obtained.
[0100]
  Example 9
  When the light emitting device is formed in the same manner as in Example 1 except that the light emitting element is sealed in advance with silica gel containing 50 wt% of the fluorescent material, the same effect as in Example 5 is obtained.
[0101]
  (Example 10)
  The surface of the light emitting element is coated with the fluorescent material and SiO.₂A light-emitting device is formed in the same manner as in Example 1 except that a continuous color conversion layer having s is formed by spray coating. Here, a method for forming the color conversion layer will be described in detail.
[0102]
  Step 1.
  As the alkyl silicate, methyl silicate, ethyl silicate, N-propyl silicate, N-butyl silicate can be used.₂A colorless and transparent oligomer liquid condensed with ethyl silicate containing 40 wt% is used. In addition, ethyl silicate is used that has been previously reacted with water in the presence of a catalyst to undergo a hydrolysis reaction to form a sol.
[0103]
  First, a coating solution is prepared by stirring a solution in which sol-form ethylsilicate, ethylene glycol, and a fluorescent substance are mixed at a weight ratio of 1: 1: 1. Here, since sol-like ethylsilicate is easy to dry, it is preferable to prevent gelation by mixing with a high boiling point (100 ° C. to 200 ° C.) organic solvent such as butanol or ethylene glycol. When mixed with a high-boiling organic solvent in this way, clogging of the nozzle tip due to gelation of the sol-like ethyl silicate can be prevented and work efficiency can be improved.
[0104]
  Step 2.
  The coating liquid is placed in a container, and the coating liquid is conveyed from the container to the nozzle by a circulation pump. The flow rate of the coating solution is adjusted by a valve. Here, the mist-like coating liquid ejected from the nozzle is sprayed while being rotated in a mist-like and spiral manner. Specifically, the spray spreads in a conical shape in the vicinity of the nozzle, and spreads in a cylindrical shape as the distance from the nozzle increases. Accordingly, the upper surface, side surfaces, and corners of the light emitting element can be covered with a continuous color conversion layer in which the film thickness is substantially equal and the fluorescent material is uniformly dispersed, and color unevenness such as blue ring is obtained. Can be improved. The color conversion layer is preferably composed of a single particle layer, which improves the light extraction efficiency. In this embodiment, the distance from the upper surface of the light emitting element to the lower end of the nozzle is set to 40 to 50 mm so that the surface of the light emitting element is placed in a state where the spray spreads in a columnar shape, and the coating liquid and the gas are put into the light emitting element. A continuous color conversion layer having a substantially uniform film thickness is formed on the upper surface, side surfaces and corners of the substrate, and on the inner surface of the recess.
[0105]
  Moreover, the said process is performed in the state which heated the place to apply | coat. As a result, the ethanol or solvent generated by the sol-formation of ethyl silicate can be instantaneously blown onto the light emitting element. Accordingly, the color conversion layer can be provided without adversely affecting the light emitting element. In this embodiment, spray coating is performed while placing the package on the heater, and the temperature of the heater is preferably adjusted to a temperature of 50 ° C. or higher and 300 ° C. or lower.
[0106]
  Step 3.
  After performing Step 2, when left at room temperature, the sol-form ethyl silicate reacts with moisture in the air, and SiO 2₂As a result, the fluorescent substance is fixed.
[0107]
  Step 4.
  Next, it is dried at a temperature of 300 ° C. for 2 hours. When nitride-based light-emitting elements are placed at a temperature of 350 ° C. or higher, the performance as light-emitting elements deteriorates. Therefore, alkylsilicates that can be fixed to the surface of light-emitting elements at a temperature of 300 ° C. It can be preferably used as an agent.
[0108]
  Since all the light emitting devices configured as described above are made of an inorganic material, the light emitting device has high heat dissipation and is excellent in light resistance against near ultraviolet rays and ultraviolet rays. The light emitting device of this embodiment can use any element such as a light emitting element that emits light in the ultraviolet region.
[0109]
  (Example 11)
  As the fluorescent material, the first fluorescent material (Y_0.995Gd_0.005)_2.750Al₅O₁₂: Ce_0.250And second fluorescent substance Ca_1.8Eu_0.2Si₅N₈When a light emitting device is formed in the same manner as in Example 8 except that a mixture of and dispersed is used, a light emitting device having better color rendering than in Example 8 is obtained. The second fluorescent material that can be used in this embodiment is not particularly limited, but MxSiyNz: Eu () having an excitation wavelength similar to that of the first fluorescent material and capable of emitting yellow to red fluorescence. However, when M is at least one alkaline earth metal selected from the group of Ca, Sr, Ba, and Zn, z = (2/3) x + (4/3) y), an excellent color rendering property is obtained. The light which has is obtained and is preferable.
[0110]
  Specifically, the phosphor is LMN: R or LMON: R (L is one selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn). M contains at least one selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf, N is nitrogen, O is oxygen, and R is a rare earth element. Nitride-based phosphors represented by the following formula:_xM_yN_{{(2/3) x + (4/3) y}}: R or L_xM_yO_zN_{{(2/3) x + (4/3) y- (2/3) z}}: R (L contains at least one selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn. M is selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, Hf) 1 or more, N is nitrogen, O is oxygen, R is a rare earth element), and is preferably a nitride-based phosphor having a crystal structure. By using such a phosphor, a light emitting device capable of emitting warm white light can be obtained.
[0111]
  Specific examples of basic constituent elements include Ca and Mu and B added.₂Si₅O_0.1N_7.9: Eu, Sr₂Si₅O_0.1N_7.9: Eu, (Ca_aSr_1-a)₂Si₅O_0.1N_7.9: Eu, CaSi₇O_0.5N_9.5: Eu, and further Ca added with rare earth₂Si₅O_0.5N_7.9: Eu, Sr₂Si₅O_0.5N_7.7: Eu, (Ca_aSr_1-a)₂Si₅O_0.1N_7.9: Eu etc.
[0112]
  Furthermore, Sr₂Si₅N₈: Eu, Pr, Ba₂Si₅N₈: Eu, Pr, Mg₂Si₅N₈: Eu, Pr, Zn₂Si₅N₈: Eu, Pr, SrSi₇N₁₀: Eu, Pr, BaSi₇N₁₀: Eu, Ce, MgSi₇N₁₀: Eu, Ce, ZnSi₇N₁₀: Eu, Ce, Sr₂Ge₅N₈: Eu, Ce, Ba₂Ge₅N₈: Eu, Pr, Mg₂Ge₅N₈: Eu, Pr, Zn₂Ge₅N₈: Eu, Pr, SrGe₇N₁₀: Eu, Ce, BaGe₇N₁₀: Eu, Pr, MgGe₇N₁₀: Eu, Pr, ZnGe₇N₁₀: Eu, Ce, Sr_1.8Ca_0.2Si₅N₈: Eu, Pr, Ba_1.8Ca_0.2Si₅N₈: Eu, Ce, Mg_1.8Ca_0.2Si₅N₈: Eu, Pr, Zn_1.8Ca_0.2Si₅N₈: Eu, Ce, Sr_0.8Ca_0.2Si₇N₁₀: Eu, La, Ba_0.8Ca_0.2Si₇N₁₀: Eu, La, Mg_0.8Ca_0.2Si₇N₁₀: Eu, Nd, Zn_0.8Ca_0.2Si₇N₁₀: Eu, Nd, Sr_0.8Ca_0.2Ge₇N₁₀: Eu, Tb, Ba_0.8Ca_0.2Ge₇N₁₀: Eu, Tb, Mg_0.8Ca_0.2Ge₇N₁₀: Eu, Pr, Zn_0.8Ca_0.2Ge₇N₁₀: Eu, Pr, Sr_{0. 8}Ca_0.2Si₆GeN₁₀: Eu, Pr, Ba_0.8Ca_0.2Si₆GeN₁₀: Eu, Pr, Mg_0.8Ca_0.2Si₆GeN₁₀: Eu, Y, Zn_0.8Ca_0.2Si₆GeN₁₀: Eu, Y, Sr₂Si₅N₈: Pr, Ba₂Si₅N₈: Pr, Sr₂Si₅N₈: Tb, BaGe₇N₁₀: Ce can be produced, but is not limited thereto. Similarly, it is naturally conceivable that the phosphors described by these general formulas appropriately contain suitable elements such as the third component, the fourth component, and the fifth component as desired.
[0113]
  Example 12
  When a light emitting device was formed by the same method as in Example 11 except that the phosphor was bound by adjusting the coating solution using a fluororesin (PTFE = polytetrafluoroethylene) instead of ethyl silicate, Example 11 And a good production yield can be obtained.
[0114]
  (Example 13)
  An LED chip having a dominant wavelength of 400 nm is used as the light emitting element, and (Sr_0.96, Eu_0.01, Mn_0.03)₁₀(PO₄)₆Cl₂A light emitting device is formed in the same manner as in Example 11 except that is used.
[0115]
  Here, a method for forming the fluorescent material will be described. First, each raw material SrHPO₄, SrCO₃, Eu₂O₃, MnCO₃, NH₄Adjust and mix Cl so as to have the above composition ratio. (SrHPO₄: 1000g, SrCO₃: 482.4 g, Eu₂O₃: 16.0 g, MnCO₃: 35.2 g, NH₄Cl: 116.5 g)
[0116]
  Next, the raw materials are weighed and thoroughly mixed by a dry method using a mixer such as a ball mill. This mixed raw material is packed in a crucible such as SiC, quartz, or alumina, and N₂, H₂In a reducing atmosphere, the temperature is raised to 1200 ° C. at 960 ° C./hr, and firing is performed at a constant temperature portion of 1200 ° C. for 3 hours. The obtained fired product is pulverized, dispersed, sieved, separated, washed with water and dried in water to obtain the desired phosphor powder.
[0117]
  When the fluorescent material thus obtained is applied to the periphery of the light emitting element and the flat surface in the concave portion in the same manner as in Example 10 to form a color conversion layer, a light emitting device capable of emitting light with high luminance is obtained.
[0118]
  (Example 14)
  CaHPO as raw material₄, CaCO₃, Eu₂O₃, MnCO₃, NH₄Cl and NH₄Br is used (Ca_0.93, Eu_0.05, Mn_0.02)₁₀(PO₄)₆Br_1.0Cl_1.0The composition ratio is adjusted and mixed.
[0119]
  The raw materials are weighed and mixed thoroughly by a dry method using a mixer such as a ball mill. This goto raw material is packed in a crucible such as SiC, quartz, alumina, etc.₂, H₂In a reducing atmosphere, the temperature is raised to 1200 ° C. at 960 ° C./hr, and firing is performed at a constant temperature portion of 1200 ° C. for 3 hours. The obtained fired product is pulverized, dispersed, sieved, separated, washed with water and dried in water to obtain the desired phosphor powder. A light emitting device capable of emitting light with high luminance can be obtained by coating the periphery of the light emitting element and the inner surface of the recess in the same manner as in Example 13 except that this fluorescent material is used to form a color conversion layer.
[0120]
  (Example 15)
  As the fluorescent material, the first fluorescent material (Y_0.995Gd_0.005)_2.750Al₅O₁₂: Ce_0.250And second fluorescent material (Ca_0.93, Eu_0.05, Mn_0.02)₁₀(PO₄)₆Br_1.0Cl_1.0A white light source capable of emitting light with high brightness can be obtained by forming a light emitting device in the same manner as in Example 13 except that a mixture of and dispersed is used.
[0121]
  (Example 16)
  (Ca_0.93, Eu_0.05, Mn_0.02)₁₀(PO₄)₆Br_1.0Cl_1.0Fluorescent material is Al₂O₃After the coating liquid consisting of the above is applied by spraying on the periphery of the light emitting element and the plane in the recess to form the first color conversion layer, the first color conversion layer is contacted (Y_0.995Gd_0.005)_2.750Al₅O₁₂: Ce_0.250The fluorescent material was made of SiO in the same manner as in Example 11 using sol-like ethyl silicate.₂A light emitting device is formed in the same manner as in Example 14 except that the second color conversion layer fixed by is formed. By forming in this way, the optical refractive index of the second color conversion layer <the optical refractive index of the first color conversion layer <the refractive index of the gallium nitride compound semiconductor layer, and the light from the light emitting element can be obtained. A light-emitting device capable of emitting light at high output with increased extraction efficiency can be obtained.
[0122]
  (Example 17)
  The first fluorescent substance Y with respect to 100% by weight of the gel silicone resin_2.985Al₃Ga₄O₁₂: Ce_0.03520 wt% and the second fluorescent substance Ca_1.8Eu_0.2Si₅N₈When a light emitting device is formed in the same manner as in Example 1 except that 5 wt% mixed and dispersed is used as the flexible member, warm white light having a color temperature of 2700 K is obtained.
[0123]
  (Example 18)
  As shown in FIG. 12, the corner portion of the first main surface has a protruding portion exposed from the outside of the second main surface 1c toward the package outer corner portion, and the protruding portion faces the package outer corner portion. A light-emitting device is formed in the same manner as in Example 1 except that a package having a substantially trapezoidal shape that spreads out at the end is used. Thereby, when a lens is pressed in the shape of a gel-like silicone resin, the gel-like silicone resin can be prevented from overflowing to the upper surface of the package. The number of the projecting portions is not particularly limited, but when formed in pairs with each corner portion of the package, the overflow effect can be uniformly applied to the entire package.
[0124]
  Example 19
  As shown in FIG. 17, the light emitting device is the same as in Example 1 except that a substantially truncated cone having a top surface smaller than the bottom surface is formed on the first main surface, and the top surface is used as a lens support surface. Form. Thereby, it can suppress that the interface of a gel-like silicone resin and a lens peels according to a thermal expansion coefficient difference. It is preferable that three or more of the substantially truncated cones are formed at equal intervals, which further increases the peeling prevention effect.
[0125]
  (Example 20)
  As shown in FIG. 14, Example 1 is used except that a substantially semicircular cylinder like a kamaboko is formed on the first main surface and a vertex line of the curved surface of the substantially semicircular cylinder is used as a lens support line. When the light emitting device is formed in the same manner as in Example 19, the effect of preventing peeling can be further enhanced as compared with Example 19, and a light emitting device having high reliability can be obtained. Like the substantially truncated cone, it is preferable that three or more substantially semicircular cylinders are formed at equal intervals, which further increases the effect.
[0126]
  (Example 21)
  A surface mount light emitting device as shown in FIG. 19 is formed. The light emitting device is the same as in Example 1 except that the submount is fixed with Ag paste in the recess provided on the metal substrate, and the light emitting element is flip-chip mounted on the submount 9 using the metal bump. When the is formed, the optical characteristics and reliability are further improved. Here, as the submount, various types such as a protective element made of a silicon semiconductor and a metal base made of aluminum nitride can be used. If the submount itself is conductive, SiO₂It is possible to use a laminate of conductive patterns with an insulating film such as SiN. Further, the material of the metal bump is not particularly limited as long as it is conductive, and Au bump, Sn-Pb solder bump, Zn-Ag solder bump, or the like can be used.
[0127]
【The invention's effect】
  In the light emitting device of the present invention, when the package on which the light emitting element is placed is sealed with the first sealing member having flexibility and the second sealing member having rigidity, the light emitting device is consistent from the inside of the package to the upper side. By providing the path, air bubbles can be prevented from being mixed between the first sealing member and the second sealing member, and once mixed in the first sealing member. It is possible to efficiently degas bubbles that have been trapped.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a light emitting device of the present invention.
FIG. 2 is a schematic cross-sectional view taken along the line II-II in FIG.
3 is a schematic cross-sectional view taken along line III-III in FIG. 1. FIG.
FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG.
5 is a schematic cross-sectional view showing a step of forming the light emitting device of Example 10. FIG.
6 is a schematic cross-sectional view showing a step of forming the light emitting device of Example 10. FIG.
7 is a schematic cross-sectional view showing a step of forming the light emitting device of Example 10. FIG.
8 is a schematic cross-sectional view showing a step of forming the light emitting device of Example 10. FIG.
FIG. 9 is a schematic cross-sectional view showing another light emitting device of the present invention.
FIG. 10 is a schematic cross-sectional view showing another light emitting device of the present invention.
FIG. 11 is a schematic cross-sectional view showing another light emitting device of the present invention.
FIG. 12 is a schematic cross-sectional view showing another light emitting device of the present invention.
13 is a schematic cross-sectional view taken along line XIII-XIII in FIG.
FIG. 14 is a schematic cross-sectional view showing another light-emitting device of the present invention.
FIG. 15 is a schematic cross-sectional view taken along line XV-XV in FIG.
FIG. 16 is a schematic cross-sectional view showing another light emitting device of the present invention.
FIG. 17 is a schematic cross-sectional view showing another light emitting device of the present invention.
18 is a schematic cross-sectional view taken along line XVIII-XVIII in FIG.
FIG. 19 is a schematic cross-sectional view showing another light emitting device of the present invention.
20 is a schematic cross-sectional view taken along line XX-XX in FIG.
FIG. 21 is a schematic cross-sectional view showing another light emitting device of the present invention.
22 is a schematic cross-sectional view taken along line XXII-XXII in FIG. 21. FIG.
FIG. 23 is a schematic cross-sectional view of a light-emitting device shown for comparison with the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Package, 1a ... Package recessed part, 1b ... 1st main surface, 1c ... 2nd main surface, 1d ... 3rd main surface, 2 ... Light emitting element chip DESCRIPTION OF SYMBOLS 3 ... Flexible member, 4 ... Rigid member, 5 ... Lead electrode, 6 ... Metal base | substrate, 7 ... Wire, 8 ... Fluorescent substance, 9 ... Submount.

Claims (9)

A light emitting element disposed in a recess provided in the package, a first light transmissive member covering the light emitting element, and a second light transmissive member placed on the first light transmissive member; A light emitting device comprising:
The second translucent member has a convex shape protruding in the direction of the light emitting element, and a flange on the outside of the convex shape, and the flange is in the recess of the package. A light-emitting device that is disposed and covered with the first light- transmissive member . The concave portion of the package includes at least a first main surface, a second main surface that extends outward above the first main surface, and a third main that extends outward above the second main surface. And having a surface,
2. The light emitting device according to claim 1 , wherein the second translucent member has at least three contacts with the second main surface on a back surface thereof. The exposed portion has an exposed portion outside the contact, and the first translucent member is formed by the exposed portion, the first main surface, the second main surface, and the back surface of the second translucent member. The light-emitting device according to claim 2 , wherein the light-emitting device is provided continuously. The outline of the second major surface, the light emitting device according to claim 2 or 3 is a polygon having a number of corners than the outline of the second transparent member. The rear of the second light transmitting member, the light emitting device according to any one of claims 2 to 4 which is curved in the contact. The light emitting element has a pair of positive and negative electrodes on the same surface side, and these electrodes are respectively connected to a pair of positive and negative lead electrodes provided in the package via wires,
The apex of the wire, the light emitting device according to 5 claim 2 which is disposed between the second major surface and the first major surface. The concave portion of the package has at least a first main surface and a second main surface extending outwardly above the first main surface,
The first main surface has a shape of a plurality of truncated cones, and the second translucent member has at least three contacts with the upper surface of the truncated cone on the back surface thereof. The light emitting device according to claim 1 . The concave portion of the package has at least a first main surface and a second main surface extending outwardly above the first main surface,
The first main surface has a plurality of kamaboko shapes, and the second translucent member has at least three contacts with the apex of the kamaboko shape on the back surface thereof. 2. The light emitting device according to 1 . A light emitting element disposed in a recess provided in the package, a first light transmissive member covering the light emitting element, and a second light transmissive member placed on the first light transmissive member; A method of manufacturing a light emitting device comprising:
A first step of covering the light emitting element disposed in the recess with a first light-transmissive member;
The first translucent member is pressed by the convex shape of the second translucent member having a convex shape protruding in the direction of the light emitting element and a flange on the outer side of the convex shape. And a second step of causing the first light-transmissive member to flow above the flange portion disposed in the recess of the package.

Images