JP2019161239A - Light emitting device - Google Patents

Abstract

To provide a light emitting device which enables batwing light distribution, in which color unevenness of light distribution is improved, without using a secondary lens.SOLUTION: A light emitting device includes: a base substance 101 having conductor wiring 102; a light emitting element 105 placed on the base substance 101 and electrically connected with the conductor wiring 102; and a translucent sealing member 108 covering the light emitting element 105. The sealing member 108 has a protruding shape. A height of the sealing member 108 is longer than a width of a bottom surface of the sealing member 108 when viewed in an optical axis L direction. Further, the sealing member 108 includes a light diffusion material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device.

In recent years, various electronic components have been proposed and put into practical use, and the performance required for them has been increased. In particular, electronic components are required to maintain long-term performance even under severe usage environments. Such a requirement is no exception for a light emitting device using a semiconductor light emitting element such as a light emitting diode (LED). That is, in the general lighting field and the in-vehicle lighting field, the performance required for the light emitting device is increasing day by day, and further higher output (high luminance) and higher reliability are required. Furthermore, it is also required to supply at a low price while maintaining these high performances.
Especially for backlights and general lighting fixtures used in liquid crystal televisions, the importance of design is emphasized, and there is a strong demand for thinning.

For example, Patent Document 1 realizes a batwing-type light distribution characteristic by combining a secondary optical lens with an LED, and can uniformly diffuse light over a short irradiation distance, resulting in a thinner instrument. Is disclosed.
Patent Document 2 discloses that a batwing light distribution is realized by devising a mold shape.

JP 2006-114863 A JP 2012-231036 A

However, in the method combined with the secondary lens described in Patent Document 1, Fresnel loss due to surface reflection occurs at the time of incidence to the secondary lens and at the time of emission from the secondary lens, and the light utilization efficiency decreases. In addition, the cost of the lens and the mounting cost of the lens are generated, and the cost increases.
In the method described in Patent Document 2, since the thickness of the phosphor-containing layer varies depending on the angle and light distribution color unevenness occurs, improvement in color unevenness has been desired.

  Embodiments according to the present invention have been made in view of such circumstances, and provide a light-emitting device that enables batwing light distribution with improved light distribution color unevenness without using a secondary lens.

  The light-emitting device according to the present embodiment includes a base body having conductor wiring, a light-emitting element placed on the base body and electrically connected to the conductor wiring, and a translucent sealing covering the light-emitting element. The sealing member has a convex shape, the height in the optical axis direction is longer than the width of the bottom surface of the sealing member, and contains a light diffusing material.

  According to the embodiment of the present invention, it is possible to provide a light emitting device that enables batwing light distribution with improved light distribution color unevenness without using a secondary lens.

It is the top view and sectional drawing which show an example of the light-emitting device of this embodiment. It is a figure which shows the light distribution characteristic of the light-emitting device of this embodiment. It is sectional drawing which shows an example of the light-emitting device of this embodiment. It is sectional drawing which shows an example of the light-emitting device of this embodiment. It is sectional drawing which shows an example of the light-emitting device of this embodiment. It is a top view which shows an example of the light-emitting device of this embodiment. It is a figure which shows the example of the shape of the sealing member of the light-emitting device of Examples 3-5. It is a figure which shows the light distribution characteristic of the light-emitting device of Examples 3-5. It is a figure which shows the luminance distribution of the light-emitting device of Examples 3-5. It is a luminance distribution figure of Examples 3-5.

Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. However, the light-emitting device described below is for embodying the technical idea, and the present invention is not limited to the following unless otherwise specified. In addition, the contents described in one embodiment and example can be applied to other embodiments and examples.
Further, in the following description, the same name and reference sign indicate the same or the same members, and detailed description will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are configured by the same member and the plurality of elements are shared by one member. It can also be realized by sharing.

[First Embodiment]
1A and 1B are schematic structural views showing an example of the light-emitting device of the first embodiment. FIG. 1A is a top view, and FIG. 1B is FIG. It is sectional drawing in the II line | wire.
As shown in FIG. 1, the light emitting element 105 is mounted on the base 101 in this embodiment by flip chip mounting via a connecting member 103 so as to straddle a pair of conductor wirings 102 provided on the surface of the base. Has been. A region electrically connected to the light emitting element 105 on the upper surface of the conductor wiring 102 is exposed from the insulating member 104.

  An underfill 106 is formed under the light emitting element 105 (that is, between the lower surface of the light emitting element 105 and the base 101) and the side surface of the light emitting element 105, and a sealing member 108 containing a light diffusing material is formed thereon. ing.

  The sealing member 108 has a convex shape (for example, a substantially hemispherical shape, a substantially conical shape, a substantially cylindrical shape, a mushroom shape, etc.), and the height A in the optical axis (L) direction is the width of the bottom surface of the sealing member 108. It is formed to be longer than C. In the description in this specification, a normal line passing through the center of the light emitting element 105 is referred to as an optical axis L. With such a configuration, the light emitted from the light emitting element 105 is scattered by the light diffusing material, and the light intensity emitted from the light emitting device 100 is substantially proportional to the apparent area ratio of the sealing member 108. As a result, the bat wing type light distribution characteristic as shown in FIG. 2 can be realized. That is, the light emitting device 100 according to the present embodiment exhibits a light distribution characteristic such that the center part becomes darker than the outer peripheral part when the light emitting element 105 is turned on and observed from the optical axis direction.

  The sealing member 108 is formed so that its outer shape is circular or elliptical when viewed from above. In the case of an elliptical shape, the bottom surface radius B has a major radius and a minor radius. The radius is defined as radius B.

FIG. 2 is a diagram illustrating the light distribution characteristics of the light emitting device according to the present embodiment. As shown in FIG. 2, the light-emitting device of this embodiment has a so-called batwing type light distribution in which the relative luminous intensity near 50 to 60 ° becomes stronger and the light distribution becomes wider than when the light distribution angle is 0 °. Has characteristics.
In FIG. 2, the aspect ratio (A / B) obtained by dividing the height A of the sealing member in the optical axis direction by the radius B of the bottom surface of the sealing member is 2.8, 3.2, and 3.5. Each case is shown. It can be seen that the greater the aspect ratio, the lower the relative luminous intensity near 0 °, and the wider the light distribution. In order to diffuse light uniformly, the aspect ratio is preferably 2.0 or more.

Since the light emitting element 105 is directly covered with the sealing member 108, the Fresnel loss can be reduced and the light extraction efficiency can be improved as compared with the case where a secondary lens is used.
The light emitting element 105 is preferably disposed at a height within 0.5 mm from the upper surface of the substrate.

In addition, when the concentration of the light diffusing material is increased, the light emitting device 100 according to the present embodiment exhibits a luminance distribution in which the central portion is darker than the outer peripheral portion when the light emitting element 105 is turned on and observed from the optical axis direction. .
This is because when viewed from the light emitting element 105, the optical path length in the optical axis direction is longer than the optical path length in the direction perpendicular to the optical axis, the light from the light emitting element 105 is scattered and attenuated.
Therefore, by adjusting the concentration of the light diffusing material, it is possible to reduce the amount of light in the direction of the optical axis and achieve batwing light distribution without increasing the aspect ratio. .

Hereinafter, the preferable form of the light-emitting device 100 which concerns on this Embodiment is demonstrated.
(Substrate 101)
The base 101 is a member on which the light emitting element 105 is placed. The substrate 101 has a conductor wiring 102 for supplying power to the light emitting element 105 on the surface thereof.
Examples of the material of the substrate 101 include resins such as ceramics, phenol resin, epoxy resin, polyimide resin, BT resin, polyphthalamide (PPA), and polyethylene terephthalate (PET). Among these, it is preferable to select a resin as an insulating material from the viewpoint of low cost and ease of molding. Alternatively, ceramics is preferably selected as the material of the substrate 101 in order to obtain a light emitting device having excellent heat resistance and light resistance.

Examples of ceramics include alumina, mullite, forsterite, glass ceramics, nitrides (for example, AlN), carbides (for example, SiC), and the like. Among these, ceramics made of alumina or mainly composed of alumina is preferable.
In the case of using a resin material constituting the substrate 101, and a glass _fiber, an inorganic filler such as _{SiO 2, TiO 2, Al 2} O 3 were mixed in a resin, the improvement of mechanical strength, reduction in coefficient of thermal expansion In addition, the light reflectance can be improved. The substrate 101 may be any substrate as long as the pair of conductor wirings 102 can be insulated and separated, and a so-called metal substrate in which an insulating layer is formed on a metal member may be used.

(Conductor wiring 102)
The conductor wiring 102 is a member that is electrically connected to the electrode of the light emitting element 105 and supplies a current (electric power) from the outside. That is, it plays a role as an electrode for energizing from the outside or a part thereof. Usually, it is formed to be separated into at least two of positive and negative.

  The conductor wiring 102 is formed on at least the upper surface of the base body on which the light emitting element 105 is placed. The material of the conductor wiring 102 can be appropriately selected depending on the material used for the substrate 101, the manufacturing method, and the like. For example, when ceramic is used as the material of the substrate 101, the material of the conductor wiring 102 is preferably a material having a high melting point that can withstand the firing temperature of the ceramic sheet. For example, a high melting point metal such as tungsten or molybdenum is used. It is preferable to use it. Furthermore, you may coat | cover with other metal materials, such as nickel, gold | metal | money, and silver, by plating, sputtering, vapor deposition, etc. on it.

  Further, when glass epoxy resin is used as the material of the base 101, the material of the conductor wiring 102 is preferably a material that can be easily processed. When using an injection-molded epoxy resin, the material of the conductor wiring 102 is preferably a member that can be easily processed by stamping, etching, bending, and has a relatively large mechanical strength. Specific examples include metals such as copper, aluminum, gold, silver, tungsten, iron, and nickel, or metal layers such as iron-nickel alloys, phosphor bronze, iron-containing copper, and molybdenum, lead frames, and the like. Moreover, you may coat | cover the surface with a metal material further. Although this material is not specifically limited, For example, it can be set as the multilayer film using only silver, the alloy of silver, copper, gold | metal | money, aluminum, rhodium, etc., or these, silver, or each alloy. Further, as a method for arranging the metal material, a sputtering method or a vapor deposition method can be used in addition to the plating method.

(Connection member 103)
The connection member 103 is a member for fixing the light emitting element 105 to the base body 101 or the conductor wiring 102. An insulating resin or a conductive member can be used. In the case of flip chip mounting as shown in FIG. 1B, a conductive member is used. Specifically, Au-containing alloy, Ag-containing alloy, Pd-containing alloy, In-containing alloy, Pb-Pd-containing alloy, Au-Ga-containing alloy, Au-Sn-containing alloy, Sn-containing alloy, Sn-Cu-containing alloy, Sn- Cu-Ag containing alloy, Au-Ge containing alloy, Au-Si containing alloy, Al containing alloy, Cu-In containing alloy, the mixture of a metal and a flux, etc. can be mentioned.

  As the connection member 103, a liquid, paste, or solid (sheet, block, powder, wire) can be used, and can be appropriately selected depending on the composition, the shape of the substrate, and the like. . Further, these connection members 103 may be formed as a single member or may be used in combination of several kinds.

(Insulating member 104)
The conductor wiring 102 is preferably covered with an insulating member 104 except for portions that are electrically connected to the light emitting element 105 and other materials. That is, as shown in each drawing, a resist for insulatingly covering the conductor wiring 102 may be disposed on the base, and the insulating member 104 can function as a resist.

In the case of disposing the insulating member 104, not only the purpose of insulating the conductor wiring 102 but also the inclusion of a white filler similar to the underfill material described below prevents light leakage and absorption, The light extraction efficiency of the light emitting device 100 can also be increased.
The material of the insulating member 104 is a material that absorbs less light from the light emitting element and is not particularly limited as long as it is insulating. For example, epoxy, silicone, modified silicone, urethane resin, oxetane resin, acrylic, polycarbonate, polyimide, or the like can be used.

(Light emitting element 105)
The light-emitting element 105 mounted on the base is not particularly limited, and a known light-emitting element 105 can be used. However, in the present embodiment, it is preferable to use a light-emitting diode as the light-emitting element 105.
A light emitting element 105 having an arbitrary wavelength can be selected. For example, as blue and green light-emitting elements, those using ZnSe, nitride-based semiconductors (In _x Al _y Ga _1-xy N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1), or GaP are used. be able to. As the red light emitting element, GaAlAs, AlInGaP, or the like can be used. Furthermore, a semiconductor light emitting element made of a material other than this can also be used. The composition, emission color, size, number, and the like of the light emitting element to be used can be appropriately selected according to the purpose.

  Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal. It may have positive and negative electrodes on the same surface side, or may have positive and negative electrodes on different surfaces.

  The light-emitting element 105 of this embodiment includes a light-transmitting substrate and a semiconductor layer stacked over the substrate. In this semiconductor layer, an n-type semiconductor layer, an active layer, and a p-type semiconductor layer are formed in this order, an n-type electrode is formed on the n-type semiconductor layer, and a p-type electrode is formed on the p-type semiconductor layer. ing.

  As shown in FIG. 1, the electrode of the light emitting element 105 is flip-chip mounted on the conductor wiring 102 on the surface of the base 101 via the connection member 103, and is a surface opposite to the surface on which the electrode is formed, that is, translucent light. The main surface of the conductive substrate is the light extraction surface. The light emitting element 105 is disposed so as to straddle two conductor wirings 102 that are positively and negatively insulated and separated, and is electrically connected by a conductive connecting member 103 and mechanically fixed. The mounting method of the light emitting element 105 can be, for example, a mounting method using bumps in addition to a mounting method using solder paste. Further, as the light emitting element 105, a small package product in which the light emitting element is sealed with resin or the like can be used, and the shape and structure are not particularly limited.

As will be described later, when a light emitting device including a wavelength conversion member is used, a nitride semiconductor (In _x Al _y Ga _{1-x −} capable of emitting a short wavelength capable of efficiently exciting the wavelength conversion member 109 can be used. _yN , 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) are preferable.

(Underfill 106)
In the case where the light emitting element 105 is flip-chip mounted, an underfill 106 is preferably formed between the light emitting element 105 and the substrate 101. The underfill 106 contains a filler for the purpose of efficiently reflecting light from the light emitting element 105 and bringing the coefficient of thermal expansion close to that of the light emitting element 105.
The material of the underfill 106 is not particularly limited as long as the material does not absorb light from the light emitting element. For example, epoxy, silicone, modified silicone, urethane resin, oxetane resin, acrylic, polycarbonate, polyimide, or the like can be used.

  If the filler contained in the underfill 106 is a white filler, light is more easily reflected, and the light extraction efficiency can be improved. Moreover, it is preferable to use an inorganic compound as a filler. The white here includes those that appear white due to scattering when there is a difference in refractive index from the material surrounding the filler even when the filler itself is transparent.

  Here, the reflectance of the filler is preferably 50% or more, and more preferably 70% or more with respect to the light having the emission wavelength. In this way, the light extraction efficiency of the light emitting device 100 can be improved. The particle size of the filler is preferably 1 nm or more and 10 μm or less. By setting the particle size of the filler within this range, the resin fluidity as an underfill is improved, and even a narrow gap can be coated without any problem. The particle size of the filler is preferably 100 nm to 5 μm, more preferably 200 nm to 2 μm. Further, the shape of the filler may be spherical or scaly.

  In addition, it is preferable that the side surface of the light-emitting element is not covered with the underfill by appropriately selecting and adjusting the particle size of the filler and the material of the underfill. This is for securing the side surface of the light emitting element as a light extraction surface.

(Sealing member 108)
The sealing member 108 is a member disposed on the base so as to cover the light emitting element 105 in order to protect the light emitting element 105 from the external environment and optically control light output from the light emitting element. In the present embodiment, the light emitting element 105 is directly covered with the sealing member 108.

  As a material of the sealing member 108, an epoxy resin, a silicone resin, a resin obtained by mixing them, or a translucent material such as glass can be used. Among these, it is preferable to select a silicone resin in consideration of light resistance and ease of molding.

  The sealing member 108 contains a light diffusing material for diffusing light from the light emitting element 105. By having the light diffusing material, the light emitted from the light emitting element 105 in the direction of the optical axis L is diffused to the entire enclosure by the light diffusing material.

  In addition to the light diffusing material, the sealing member 108 absorbs light from the light emitting element 105 and emits light having a wavelength different from that of the output light from the light emitting element. A colorant can also be included corresponding to the emission color.

  The sealing member 108 can be formed by compression molding or injection molding so as to cover the light emitting element 105. In addition, the viscosity of the material of the sealing member 108 can be optimized, dropped or drawn on the light emitting element 105, and the shape as shown in each figure can be formed by the surface tension of the material itself.

  When the latter forming method is used, the sealing member can be formed by a simpler method without requiring a mold. Further, as a means for adjusting the viscosity of the material of the sealing member by such a forming method, in addition to the inherent viscosity of the material, a desired viscosity using the light diffusing material, the wavelength conversion member, and the colorant as described above. It can also be adjusted.

(Light diffusing material)
Specifically, as the light diffusing material, SiO ₂ , Al ₂ O ₃ , Al (OH) ₃ , MgCO ₃ , TiO ₂ , ZrO ₂ , ZnO, Nb ₂ O ₅ , MgO, Mg (OH) ₂ , SrO , Oxides such as In ₂ O ₃ , TaO ₂ , HfO, SeO, Y ₂ O ₃ , CaO, Na ₂ O, B ₂ O ₃ , nitrides such as SiN, AlN, AlON, fluorides such as MgF ₂ Etc. These may be used alone or in combination. Alternatively, these may be laminated in a plurality of layers.

  Moreover, you may use an organic filler as a light-diffusion material. For example, what made various resin the particle form is mentioned. In this case, examples of various resins include silicone resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, polytetrafluoroethylene resin, epoxy resin, cyanate resin, phenol resin, acrylic resin, polyimide resin, polystyrene resin, polypropylene resin. , Polyvinyl acetal resin, polymethyl methacrylate resin, urethane resin and polyester resin.

  The light diffusing material is preferably a material that does not substantially convert the wavelength of light from the light emitting element. Thereby, the light distribution color nonuniformity by the thickness of the wavelength conversion member content layer changing with angles can be suppressed.

The content of the light diffusing material only needs to be such that light is diffused, and is, for example, about 0.01 to 30 wt%, preferably about 2 to 20 wt%. Similarly, the size of the light diffusing material may be such that light is diffused, for example, about 0.01 to 30 μm, preferably about 0.5 to 10 μm. The shape may be spherical or scaly, but is preferably spherical for uniform diffusion. However, the concentration of the light diffusing material is a material that changes relatively depending on the refractive index difference and thickness with respect to the sealing material, and the above-mentioned numbers are only a guide.
For example, the light emitting element itself usually has the highest light intensity in the optical axis direction. For this reason, when the concentration of the diffusing material is too low, there is a case where the luminance distribution at the center portion is not darker than the outer peripheral portion when the light emitting element is turned on and observed from the optical axis direction. Therefore, it is preferable to adjust the concentration of the diffusing material so that the center portion has a darker luminance distribution than the outer peripheral portion.

  Further, by controlling the concentration of the light diffusing material in the sealing member 108, the light emitting device 100 can be observed from the optical axis, and the center can be darkened and the outer periphery can be brightened. By adopting such a configuration, the amount of light in the optical axis direction can be further suppressed, and a batwing type light distribution characteristic can be obtained.

  In the light emitting device of the present embodiment, wide light distribution can be realized without using a secondary lens. Therefore, when a plurality of light emitting elements 105 are mounted on the base 101, the interval between adjacent light emitting elements is small. Even if it is 20 mm or more, light can be uniformly diffused at a short irradiation distance. Thereby, the surface light source by which the brightness nonuniformity was suppressed using a some light emitting element is realizable. Here, the interval between the adjacent light emitting elements means the shortest distance between the two adjacent light emitting elements 105 as shown by a distance F in FIG.

[Second Embodiment]
FIG. 3 is a cross-sectional view illustrating an example of the light emitting device of the second embodiment.
In this embodiment, the wavelength conversion member 109 is disposed in contact with the light emitting element 105, and the sealing member 108 containing the light diffusing material is formed so as to cover the wavelength conversion member 109.

  As described above, when the wavelength conversion member is contained in the entire sealing member 108, the thickness of the wavelength conversion member-containing layer varies depending on the angle, and light distribution color unevenness occurs. Therefore, in this embodiment, the wavelength conversion member 109 is formed around the light emitting element 105, and the sealing member 108 having optical performance is formed thereon. Thereby, since the region where the wavelength conversion is performed (the wavelength conversion member 109) and the region where the optical performance is imparted (the sealing member 108) can be formed separately, while realizing the desired light distribution characteristics, Light distribution color unevenness is suppressed.

(Wavelength conversion member 109)
As the wavelength conversion member, for example, any member that absorbs light from a light emitting element having a nitride semiconductor as a light emitting layer and converts the light into light having a different wavelength may be used. As the fluorescent material, for example, a nitride-based phosphor or an oxynitride-based phosphor that is mainly activated by a lanthanoid element such as Eu or Ce can be used. More specifically, it is preferably at least any one or more selected from the groups described in the following (D1) to (D3).
(D1) Alkaline earth halogen apatite, alkaline earth metal borate, alkaline earth metal aluminate, alkaline earth metal, mainly activated by lanthanoids such as Eu and transition metal elements such as Mn Fluorescent substance such as sulfide, alkaline earth metal thiogallate, alkaline earth metal silicon nitride, germanate, etc. (D2) Rare earth aluminate, rare earth silicate, alkali mainly activated by lanthanoid elements such as Ce Phosphors such as earth metal rare earth silicates (D3) Phosphors such as organic or organic complexes mainly activated by lanthanoid elements such as Eu

Among these, a YAG (Yttrium Aluminum Garnet) phosphor, which is a rare earth aluminate phosphor mainly activated by a lanthanoid element such as Ce in (D2), is preferable. The YAG phosphor is represented by the following composition formula (D21) to (D24).
(D21) Y ₃ Al ₅ O ₁₂ : Ce
_{(D22) (Y 0.8 Gd 0.2} ) 3 Al 5 O 12: Ce
_{(D23) Y 3 (Al 0.8} Ga 0.2) 5 O 12: Ce
(D24) (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce

For example, part or all of Y may be substituted with Tb, Lu, or the like. _{Specifically, Tb 3 Al 5 O 12:} Ce, Lu 3 Al 5 O 12: may be Ce or the like. Furthermore, phosphors other than the above-described phosphors having the same performance, function, and effect can be used.

The particle size of such a phosphor is preferably about 2.5 to 30 μm, for example.
In the present specification, the term “particle size” refers to an average particle size, and the value is determined by the air permeation method or F.I. S. S. S. No (Fisher-SubSieve-Sizers-No.) (A value represented by a so-called D bar (bar above D)).

The wavelength conversion member may be, for example, a so-called nanocrystal or a luminescent material called a quantum dot. Examples of such materials include semiconductor materials such as II-VI, III-V, IV-VI, and I-III-VI semiconductors, specifically CdSe, core-shell CdS _X Se _1. Nano-sized highly dispersed particles such as _{—X 2} / ZnS, GaP, InAs, InP, GaN, PbS, PbSe, Cu (In, Ga) S ₂ , and Ag (In, Ga) S ₂ can be mentioned. Such quantum dots can have, for example, a particle size of 1 to 100 nm, preferably about 1 to 20 nm (about 10 to 50 atoms). By using quantum dots having such a particle size, internal scattering can be suppressed, and light scattering in the wavelength conversion region can be suppressed.

The light emitting device 200 shown in FIG. 3 may have the same configuration as the light emitting device 100 of the first embodiment except that the light emitting element 105 has a wavelength conversion member 109 around it.
In the present embodiment, the wavelength conversion member 109 has a convex shape in the optical axis L direction, like the sealing member 108. The wavelength conversion member 109 is disposed in contact with a portion where the surface of the light emitting element 105 is exposed so that the wavelength conversion is performed from the light emitting element to the sealing member 108. In the example shown in FIG. 3, the wavelength conversion member 109 is formed in a substantially hemispherical shape that covers the light emitting element 105.

  The wavelength conversion member 109 is preferably formed so that its outer shape is circular or elliptical when viewed from above.

  The height (D) of the wavelength conversion member 109 in the optical axis (L) direction is preferably ½ or less of the height (A) of the sealing member 108 in the optical axis (L) direction. Thereby, the thickness of the sealing member 108 can be ensured, and color unevenness can be reduced.

  The width (E) of the wavelength conversion member 109 is preferably 4/5 or less of the width (C) of the sealing member 108. Thereby, the thickness of the sealing member 108 can be ensured, and color unevenness can be reduced.

  Note that the sealing member 108 of the light emitting device of the second embodiment may further contain a wavelength conversion member such as a phosphor. In this case, the emission wavelength of the wavelength conversion member 109 is preferably longer than the emission wavelength of a wavelength conversion member such as a phosphor contained in the sealing member 108. Thereby, it can suppress that the light wavelength-converted by the wavelength conversion member 109 is wavelength-converted again by the wavelength conversion member contained in the sealing member.

[Modification of Second Embodiment]
FIG. 4 is a cross-sectional view showing a modification of the light emitting device 200 of the second embodiment. The light emitting device 300 according to this modification uses a small LED package product that includes a wavelength conversion member and a reflection member 203 in the light emitting element as the light emitting element 105. Specifically, the LED package 201 in which the side surface and the lower surface of the light emitting element 105 are covered with the reflection member 203 and the wavelength conversion member 109 is provided on the upper surface of the light emitting element 105 is mounted on the base 101. The terminal 204 of the LED package 201 and the conductor wiring 102 are electrically connected by the connecting member 103.

  Also according to this modification, similarly to the second embodiment, a region where wavelength conversion is performed and a region where optical performance is imparted can be formed separately, and thus light distribution color unevenness is suppressed. With such a configuration, it is possible to use a light source whose chromaticity has been selected in advance, so that the chromaticity yield of the product can be improved.

[Third Embodiment]
FIG. 5 is a cross-sectional view illustrating an example of the light emitting device 400 of the third embodiment.
In the present embodiment, the radius of the region where the sealing member 108 and the base 101 are in contact (the bottom surface of the sealing member 108) is smaller than the maximum radius in the width direction of the sealing member 108. As described above, since the sealing member 108 has the inversely tapered portion 205 in the vicinity of the base 101, the light emitted from the light emitting element in the lateral direction with respect to the optical axis (L) is changed in direction toward the top surface of the base by refraction. Thus, the amount of light that illuminates the entire surface without hitting the substrate can be increased. The sealing member 108 may have a configuration similar to that of the light emitting device 100 of the first embodiment or the light emitting device 200 of the second embodiment, except that the sealing member 108 has a reverse taper shape in the vicinity of the base 101.

Hereinafter, although an example explains concretely, the present invention is not limited to these examples.
[Example 1]
In this embodiment, as shown in FIGS. 1A and 1B, a glass epoxy base material is used as the base 101, and a 35 μm Cu material is used as the conductor wiring.
The light emitting element is a nitride blue LED having a square shape with sides of 600 μm and a thickness of 150 μm in plan view, and an epoxy white solder resist is used for the insulating member 104. As the underfill 106, a silicone resin containing 30 wt% of titanium oxide as a filler is used, and the lower surface and side surfaces of the light emitting element 105 are covered with the underfill 106. The sealing member 108 uses a silicone resin containing 30 wt% of SiO ₂ filler as a light diffusing material, and has a substantially hemispherical shape with an outer shape in a top view as shown in FIGS. 1A and 1B. The height A in the optical axis direction is 5.5 mm, the radius B of the bottom surface of the sealing member 108 is 1.7 mm, and the aspect ratio (A / B) is 3.2.

With such a configuration, the light emitted from the light emitting device 105 is scattered by the SiO ₂ filler that is a light diffusing material, so that the light intensity emitted from the light emitting device 100 is approximately equal to the apparent area ratio of the sealing member 108. Proportional. As a result, a light distribution characteristic as shown in FIG. 2 with an aspect ratio of 3.2 can be realized. This light distribution has a higher relative light intensity near 50 ° to 60 ° than a relative light intensity near 0 °, and can be controlled as a batwing light distribution.

[Example 2]
This embodiment is the same as the first embodiment except that the sealing member 108 containing the wavelength conversion member 109 is formed around the light emitting element 105 as shown in FIG.
The wavelength conversion member 109 of this embodiment uses a silicone resin containing a YAG phosphor, and the sealing member 108 uses a silicone resin containing a SiO ₂ filler as a light diffusing material.
With such a configuration, white light is synthesized by the blue light of the light emitting element 105 and the yellow light wavelength-converted by the wavelength conversion member 109, and further diffused in the sealing member 108 so as to be omnidirectional. A bat wing light distribution with little color unevenness is obtained.

  As Examples 3 to 5, the shape of the sealing member 108 was changed, and the light distribution characteristics and the luminance distribution were confirmed. The light emitting device of Example 3 is shown in FIG. 7A, the light emitting device of Example 4 is shown in FIG. 7B, and the light emitting device of Example 5 is shown in FIG. 7C.

In the light emitting devices of Examples 3 to 5, the sealing member 108 has a convex shape, the height in the optical axis direction is longer than the width of the bottom surface of the sealing member 108, and contains a light diffusing material. And the point that the upper surface of the sealing member 108 has a curvature.
Further, a glass epoxy base material is used as the substrate, and a 35 μm Cu material is used as the conductor wiring. The light emitting element is common in that a nitride blue LED having a square of 600 μm on a side and a thickness of 150 μm is used in plan view, and an epoxy white solder resist is used as an insulating member.

[Example 3]
As shown in FIG. 7A, the sealing member 108 according to the third embodiment has a shape close to a conical shape with a curvature near the optical axis larger than that of other portions. The side surface of the sealing member also has a curvature. In Example 3, as shown in FIG. 3, the phosphor layer is formed by applying the phosphor on the light emitting element. The phosphor uses a YAG phosphor and is a white light emitting device.

[Example 4]
As shown in FIG. 7B, the sealing member 108 of Example 4 has a curvature in the vicinity of the optical axis that is smaller than the curvature in other portions, and the surface in the vicinity of the optical axis is nearly flat. . In addition, the side surface of the sealing member has a surface that is substantially perpendicular to the upper surface of the substrate (the upper surface of the light emitting element), and has a shape close to a cylindrical shape.

Such a shape can be formed as follows.
First, using a resin prepared by dispersing a diffusing material in a highly thixotropic resin by adding nanofillers, the resin is applied while pulling up by controlling the vertical direction (z direction) of the dispenser, and then pulled up to the required height. Then, pulling up is stopped and the resin is supplied until the vertical cross section is close to a rectangle. When the desired shape is obtained, the supply of the resin is terminated, and the resin is trimmed so that the upper surface is rubbed. Here, an example in which the upper surface of the sealing member has a curvature is shown, but the upper surface may be flat.
In Example 4, as in Example 3, a phosphor layer is formed by a method of applying a phosphor on a light emitting element, and a white light emitting device is obtained.

[Example 5]
The sealing member 108 of Example 5 has an upper portion 10 and a lower portion 20 as shown in FIG. 7C, and the upper portion 10 has a mushroom type having a diameter G larger than the diameter H of the lower portion 20. It is said that. In addition, in the upper part 10, the curvature in the vicinity of the optical axis is smaller than the curvatures in the other parts as in the fourth embodiment, and the surface in the vicinity of the optical axis has a substantially flat shape. The side surface of the lower portion 20 has a surface that is substantially perpendicular to the upper surface of the substrate (the upper surface of the light emitting element) and is formed in a substantially cylindrical shape, and the upper portion 10 is formed in a substantially spherical shape.
Further, the side surface of the sealing member increases in diameter from the lower side to the upper side, becomes maximum at the point of the diameter G, and gradually decreases as it goes further upward. As described above, when the light emitting device is viewed from the top, the upper portion 10 overlaps with the lower portion 20 so that the periphery of the bottom portion of the sealing member that increases the brightness is not directly visible when viewed from the top. As a result, uniformity can be improved.
In Example 5, a white light emitting device is formed by forming a phosphor layer using the LED package 201 as shown in FIG.

(Orientation characteristics and luminance distribution)
As shown in FIG. 8, the light distribution characteristics of the light emitting devices are all batwing light distribution. The light-emitting device of Example 5 exhibits substantially the same light distribution characteristics as the light-emitting devices of Examples 3 and 4 except that the brightness near the optical axis is flat.
On the other hand, FIG. 9 is a graph showing the luminance distribution in the top view of the sealing member 108 of the light emitting device of Examples 3 to 5 and the periphery thereof, and FIG. 10 is the in-plane luminance distribution in the top view. 10A shows the luminance distribution of the third embodiment, FIG. 10B shows the luminance distribution of the fourth embodiment, and FIG. 10C shows the luminance distribution of the fifth embodiment.
9 and 10, the light emitting device of Example 5 has the best uniformity. Here, the uniformity means the brightness / darkness ratio (dark part / bright part) of the brightness of the darkest part (dark part) near the optical axis and the brightness of the brightest part (bright part). The larger this value is, the smaller the difference between the bright part and the dark part, and the better the uniformity. The light / dark ratio of Example 3 is 0.157, the light / dark ratio of Example 4 is 0.557, and the light / dark ratio of Example 5 is 0.717.
When the light diffusing plate or the like, which is the irradiation surface, is very close to the light emitting device, the influence of the luminance distribution of the light emitting device itself that does not appear in the light distribution characteristics shown in FIG. The surface is dark on the optical axis, and a bright donut-like shape appears around it. On the other hand, in Examples 4 and 5, since the luminance uniformity of the light emitting device is good, it is possible to suppress the occurrence of bright and dark shapes near the irradiation surface optical axis.

From the results of Examples 3 and 4, when the curvature in the vicinity of the optical axis of the sealing member 108 is smaller than the curvature of other portions, there is a difference in the optical path length in the sealing member on and around the optical axis. Since it becomes small, the difference in the amount of light passing through in the optical axis direction becomes small, and the uniformity is improved.
The reason why the uniformity of the light emitting device of Example 5 is the best is that the reflected light from the white solder resist around the bottom of the sealing member having the highest luminance in Example 4 is shielded and scattered by the sealing member itself. This is probably because of this.
The difference in diameter between the upper portion 10 and the lower portion 20 at this time is, for example, that the diameter of the upper portion 10 is about 1.1 to 2.0 times, preferably about 1.2 to 1.5 times the diameter of the lower portion 20. . In addition, since this diameter ratio changes with the aspect ratio and light distribution characteristic of a sealing member, it is not limited to the above-mentioned range.

  The light emitting device of the present invention can be used for a backlight light source of a liquid crystal display, various lighting fixtures, and the like.

100, 200, 300, 400 Light emitting device 101 Base body 102 Conductor wiring 103 Connection member 104 Insulating member 105 Light emitting element 106 Underfill 108 Sealing member 109 Wavelength converting member L Optical axis 201 LED package 203 Reflecting member 204 Terminal 205 Reverse taper portion

Claims (13)

A substrate having conductor wiring;
A light emitting element placed on the substrate and electrically connected to the conductor wiring;
A translucent sealing member that covers the light emitting element,
The light emitting device characterized in that the sealing member has a convex shape, the height in the optical axis direction is longer than the width of the bottom surface of the sealing member, and contains a light diffusing material.   The light emitting device according to claim 1, wherein an aspect ratio obtained by dividing the height in the optical axis direction by the radius of the bottom surface of the sealing member is 2.0 or more.   The light-emitting device according to claim 1, wherein when the light-emitting element is turned on and observed from the optical axis direction, the light-emitting device exhibits a light distribution characteristic that is darker at the center than at the outer periphery.   The light-emitting device according to claim 1, wherein when the light-emitting element is turned on and observed from the optical axis direction, the center portion exhibits a luminance distribution that is darker than the outer peripheral portion.   The light emitting device according to claim 1, wherein the light emitting element is disposed at a height within 0.5 mm from the base.   The light emitting device according to any one of claims 1 to 5, wherein a plurality of the light emitting elements covered with the sealing member are mounted on the base, and an interval between adjacent light emitting elements is set to 20 mm or more. apparatus.   The light emitting device according to claim 1, further comprising a wavelength conversion member around the light emitting element.   The light emitting device according to claim 7, wherein a height of the wavelength conversion member in the optical axis direction is ½ or less of a height of the sealing member in the optical axis direction.   The light emitting device according to claim 7 or 8, wherein a width of the wavelength conversion member is 4/5 or less of a width of the sealing member.   The light emitting device according to claim 1, wherein the sealing member has a radius of a region in contact with the base that is smaller than a maximum radius in a width direction of the sealing member.   The light emitting device according to claim 1, wherein the sealing member contains a phosphor.   The light emitting device according to any one of claims 7 to 9, wherein the sealing member contains a phosphor, and the emission wavelength of the wavelength conversion member is longer than the emission wavelength of the phosphor.   The light emitting device according to claim 1, wherein the convex shape has a curvature in the vicinity of the optical axis that is smaller than the curvature of other portions.

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