JP2009094199A - Light emitting device, plane light source, display device, and method of manufacturing the light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce color irregularity caused when an observation direction is changed by suppressing variation in spectral distribution with respect to change in projection angle θ of projection light. <P>SOLUTION: A light emitting device includes a substrate, a semiconductor light emitting element die-bonded to the substrate and operative to emit primary light, and a wavelength conversion section which covers the semiconductor light emitting element and operative to absorb the primary light and emit secondary light. The wavelength conversion section is formed by dispersing a phosphor in a resin and has a shape of a truncated pyramid which is trapezoidal in a longitudinal section, and a side surface of the semiconductor light emitting element is enclosed with an inclined plane. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light-emitting device having a semiconductor light-emitting element (chip) that emits primary light and a wavelength conversion unit that includes a phosphor that absorbs primary light and emits secondary light.

  The primary light emitted from the semiconductor light emitting element is mixed with the secondary light that passes through the wavelength conversion unit and the wavelength conversion unit absorbs a part of the primary light and emits white light. A light-emitting device that emits emitted light is known.

  This light emitting device preferably obtains a uniform white color even when the emission angle θ is changed, that is, when the observation direction is changed, but there is a problem that the chromaticity actually changes. FIG. 11 is a chromaticity diagram showing a state in which the emission angle θ is changed. That is, the change in the emission angle θ changes the spectral distribution of the emitted light, and the chromaticity moves on the chromaticity diagram.

  In particular, when the light emitting devices are arranged in a plane and a surface light source is formed, color unevenness is caused, which has been an obstacle when used as a backlight of a liquid crystal display device, for example.

  As one of the causes of color unevenness, it is known that the distance that the primary light passes through the wavelength converter is nonuniform depending on the emission angle θ. The primary light is converted into secondary light by the phosphor included in the wavelength conversion unit while passing through the wavelength conversion unit. Therefore, the ratio of the primary light is increased when the distance passing through the wavelength conversion unit is short, and the ratio of the secondary light is increased when the distance is long.

  As a means for solving this problem, a light emitting element that emits blue light and a package that includes a phosphor that absorbs part of the blue light and emits yellow-green light, and the light emitting element is covered with the package. A light-emitting device manufactured in such a manner that the thickness of the package covering the light-emitting element is the same in all directions is disclosed (Patent Document 1).

In addition, a light-emitting device using electrophoretic deposition is disclosed as a method for forming the wavelength conversion unit. This is because the LED chip and the electrode are immersed in a container containing a solution containing phosphor particles, a charging material and aluminum nitride as a binder in a solvent composed of isopropyl alcohol and water, and a bias is applied between the LED chip and the electrode. It is disclosed that the phosphor layer is deposited conformally on the surface of the LED chip by electrophoresis when applied, and the thickness of the phosphor layer is sufficiently thinner than the cross-sectional dimension of the LED chip. (Patent Document 2).
JP 2000-208822 A JP 2003-69086 A

  According to Patent Document 1, a photolithography method, a screen printing method, and a transfer method are disclosed as a package forming method. According to these formation methods, the thickness of the package is such that the portion facing the side of the light emitting element and the portion facing the corner are thick, and the shape of the package cannot be reliably controlled.

  According to Patent Document 2, although a phosphor layer is deposited conformally on the surface of the LED chip, no means for reliably giving a desired shape to the phosphor layer is disclosed. Therefore, in any case, the improvement of the color unevenness is not sufficient.

  The present invention suppresses fluctuations in the spectral distribution with respect to changes in the emission angle θ of the emitted light, and improves color unevenness when the observation direction is changed.

  The light emitting device of the present invention includes a substrate, a semiconductor light emitting element that is die-bonded to the substrate, emits primary light, covers the semiconductor light emitting element, absorbs the primary light, and emits secondary light. A wavelength conversion unit that emits light, wherein the wavelength conversion unit includes a phosphor dispersed in a resin and has a truncated pyramid shape that is trapezoidal in a longitudinal section. It has a structure surrounded by an inclined surface.

  The light emitting device of the present invention includes a substrate, a semiconductor light emitting element that is die-bonded to the substrate, emits primary light, covers the semiconductor light emitting element, absorbs the primary light, and emits secondary light. A light emitting device having a wavelength converting unit that emits light, wherein the wavelength converting unit has a dome shape while a phosphor is dispersed in a resin.

  In the light emitting device of the present invention, it is preferable that the wavelength conversion unit is formed by dispersing at least two kinds of the phosphors.

  In the light emitting device of the present invention, the wavelength conversion unit includes a plurality of types of the wavelength conversion units that absorb the primary light and emit different secondary lights, and emit the secondary light having a relatively long wavelength. It is preferable that the wavelength conversion unit is arranged in order from the side close to the semiconductor light emitting element.

  The surface light source of the present invention includes the light emitting device and a mounting substrate, and has a structure in which a plurality of the light emitting devices are disposed on a surface of the mounting substrate.

  The display device of the present invention preferably has the surface light source, a liquid crystal display element, and a structure in which the surface light source irradiates the liquid crystal display element from the back.

  The method for manufacturing a light emitting device of the present invention includes a step of dispersing a phosphor in a resin to prepare a phosphor-containing resin, a step of injecting the phosphor-containing resin into a cavity of a mold, and a semiconductor light emitting element being die bonded. And a step of setting the substrate to the mold, in order, the inner wall surface of the cavity has a truncated pyramid shape that is trapezoidal in a longitudinal section, and the semiconductor light emitting element is The semiconductor light emitting device has a structure in which a side surface of the semiconductor light emitting device is surrounded by an inclined surface in a state of being immersed in the cavity.

  The method for manufacturing a light emitting device of the present invention includes a step of dispersing a phosphor in a resin to prepare a phosphor-containing resin, a step of injecting the phosphor-containing resin into a cavity of a mold, and a semiconductor light emitting element being die bonded. And a step of setting the substrate to the mold, in order, wherein the inner wall surface of the cavity has a dome shape, and the semiconductor light emitting element is immersed in the cavity. The semiconductor light emitting device has a structure surrounded by the inner wall surface.

  In the method for manufacturing a light emitting device according to the present invention, the mold includes a cavity mold having the cavity and a base mold having a pressure surface, and the cavity mold and the base mold are separated from each other. Preferably, the method includes a step of injecting the phosphor-containing resin into the cavity and a step of pressing the cavity mold and the press surface of the base mold so as to face each other.

  According to the light emitting device of the present invention, the periphery of the semiconductor light emitting element (chip) is covered with a substantially uniform thickness by the wavelength conversion unit. Accordingly, the distance that the primary light emitted from the chip passes through the wavelength conversion unit is substantially uniform even when the emission angle θ changes, so that fluctuations in the spectral distribution of the outgoing light due to changes in the emission angle θ are suppressed. be able to. Further, by arranging the light emitting devices of the present invention in a plane and forming a surface light source, uneven color of the surface light source can be suppressed. In the display device having a structure in which the liquid crystal display element is irradiated from the back surface by the surface light source of the present invention, the display quality can be improved.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1A is a diagram showing a manufacturing process of the light emitting device according to the first embodiment of the present invention. In the present embodiment, a nitride semiconductor light emitting device, which is a die bonding step for fixing a chip 3 that emits primary light, which is blue light having an emission peak wavelength of about 450 nm, to the substrate 1, and an electrode provided in the chip 3 A wire bonding process for electrically connecting the wiring pattern 2 provided on the substrate 1 is performed. Subsequently, the first wavelength conversion is performed by covering the chip 3 with a resin in which a yellow phosphor 13 that absorbs the primary light and emits secondary light that is yellow light having a peak wavelength of about 560 nm is dispersed in advance. A first resin sealing step in which the portion 11a is formed and a dicing step for separating the individual light emitting devices are sequentially performed.
(Die bonding, wire bonding)
FIG. 2 is a plan view and a cross-sectional view showing a die-bonded substrate in which a chip is die-bonded and a wire is wire-bonded.

  In the substrate 1, a plurality of wiring patterns 2 composed of wiring patterns 2a and 2b spaced apart from each other are continuously arranged on the main plane of the flat substrate 1a.

  The wiring patterns 2a and 2b are formed of a copper foil having a thickness of 70 μm, for example.

  Subsequently, the chip 3 is die-bonded on the substrate 1. The chip 3 includes a pair of electrodes including a back electrode and a front electrode (not shown). The front surface and the back electrode of one wiring pattern 2 a are fixed through a conductive brazing material (not shown), and the other wiring pattern 2 b and the front electrode are wire-bonded by a wire 4. As a result, the chip 3 is fixed at a predetermined position, and the wiring pattern 2 and the chip 3 are electrically connected.

  A notch 5 for alignment is formed at the edge of the substrate 1, and when the resin sealing described later is performed, the substrate 1 is accurately set at a predetermined position of the first cavity mold 31a. The position shift is suppressed.

Further, a through hole 6 as an external terminal is formed at a predetermined position of the substrate 1. A conductor is formed on the inner wall surface of the through hole 6 by plating or the like, and is electrically connected to an electrode pattern (not shown) formed on the surface opposite to the chip mounting surface.
(First resin sealing)
FIG. 3A is a perspective view showing the structure of a mold, and FIG. 3B is a cross-sectional view showing a state when a substrate is set in the mold.

  The mold 31 includes a first cavity mold 31a that accommodates the substrate 1 and the first sealing resin 11, and the first sealing resin 11 is injected into the first cavity mold 31a, and the substrate 1 is set and added. And a base mold 31b having a pressing surface for pressing.

  The first cavity mold 31 a includes a bathtub portion 32 formed on the surface thereof and a relief cavity 33 formed so as to surround the periphery of the bathtub portion 32.

  The bathtub portion 32 is formed in a dish shape on the surface of the first cavity mold 31a so as to fill the resin. The escape cavity 33 is formed in a groove shape so as to accommodate the resin that protrudes excessively during resin sealing.

  The bathtub portion 32 is a flat surface formed on the bottom surface of the bathtub portion 32, and a set surface 34 on which a die-bonded substrate is set, on which a chip is die-bonded, and the chip 3 is sealed and a wavelength conversion portion. And a concave first main cavity 35 that gives a predetermined shape. Although the detailed shape of the first main cavity 35 will be described later, in FIG. 3, it is described in a simplified manner. A plurality of first main cavities 35 are arranged so as to match the position of the chip 3 die-bonded to the substrate 1.

  A positioning projection 36 is provided at a predetermined position of the bathtub portion 32. The alignment protrusion 36 is engaged with the notch 5 formed in the substrate 1, thereby suppressing the positional deviation between the first main cavity 35 and the chip 3.

  FIG. 4A is an enlarged sectional view showing the shape of the first main cavity.

  The first main cavity 35 has a surface whose inner wall surface is equidistant from the outer surface of the chip 3. That is, the die-bonded substrate is set on the set surface 34, and the chip 3 has a surface parallel to the top surface and the side surface of the chip 3 in a state where the chip 3 is immersed in the first main cavity 35. Further, the portion along the side of the chip 3 has a first inclined surface 37 cut obliquely. By using the first cavity mold 31a having the first main cavity 35 as described above, the portion along the side of the chip 3 has an inclined surface, and the periphery can be covered with a substantially uniform thickness.

  In addition, in order to make mold release easy, you may equip the surface of the bathtub part 32 previously with the release sheet 38 so that it may closely_contact | adhere along the unevenness | corrugation of this surface.

  Subsequently, a first resin sealing is performed in which the chip is sealed with a resin in which the yellow phosphor 13 is dispersed in advance.

  A first sealing resin 11 in which a yellow phosphor 13 is dispersed in advance in a resin is prepared.

  The resin is required to have high durability against the primary light emitted from the chip 3 to be sealed. In the present embodiment, the primary light is blue light, and a silicone resin having high durability is suitably used. Thereby, the light quantity fall by the yellowing of resin in long-term operation | movement is suppressed, and a reliable light-emitting device is obtained.

  It should be noted that a substance other than the phosphor, for example, a filler such as silica or silicone resin may be mixed in the resin in order to suppress the bias or sedimentation of the phosphor or to scatter light.

  Subsequently, the die 31 is used, and the chip 3 is sealed by the process described below.

  First, the first sealing resin 11 is injected into the first main cavity 35 of the first cavity mold 31a placed with the bathtub portion 32 facing upward. The injection amount may be such that at least the first main cavity 35 is filled and remains on the set surface 34 to some extent. At this time, the first sealing resin 11 is gently injected so as not to generate bubbles. Further, the container in which the first sealing resin 11 is accommodated may be appropriately agitated so that the phosphor is evenly dispersed.

  Subsequently, a die-bonded substrate is set so that the mounting surface of the chip 3 faces the set surface 34 of the first cavity mold 31a filled with the first sealing resin 11, and the first cavity mold 31a and Set so as to be sandwiched between the pressing surface of the base mold 31b and clamp the mold. At this time, the position of the chip 3 corresponds to the position of the main cavity 35, and the chip 3 is immersed in the first main cavity 35. The first sealing resin 11 overflowing excessively due to mold clamping is accommodated in the escape cavity 33. The clamping pressure may be such that almost all of the sealing resin escapes from the surface of the substrate 1 when the substrate 1 is pressed against the set surface 34 and the sealing resin is pressed and spread.

  Subsequently, the mold 31 is heated to thermally cure the first sealing resin 11. Specifically, it may be cured for about several minutes in an oven at 80 ° C. to 350 ° C., for example.

  At this time, it is preferable to start thermosetting promptly because the phosphor settles down and uniform dispersion is impaired when a long time elapses between the injection of the first sealing resin 11 and the start of thermosetting. It is preferable to start within minutes.

  Next, the substrate 1 is released from the mold 31 and the release sheet 38 is removed, and after-curing is performed under high temperature conditions. Specifically, after-curing may be performed in an oven at about 350 ° C. for about 5 hours.

  Through the above-described steps, a first resin-sealed substrate in which a plurality of light-emitting devices 20 each having the chip 3 sealed with the first resin seal 11 is formed.

  As a result, the distance that the primary light passes through the first wavelength conversion unit 11a is substantially uniform even when the emission angle θ changes, so that the fluctuation of the spectrum distribution of the outgoing light due to the change of the emission angle θ. Can be suppressed.

  Thus, by performing resin sealing using a mold, it is possible to reliably give a desired shape to the wavelength conversion unit.

  Further, when forming the wavelength conversion unit using a resin in which the phosphor is dispersed, it is preferable that the phosphor is evenly dispersed. According to the above-described process, it is not necessary to provide the mold 31 with a resin inlet or injection path. Therefore, when a mold having an injection path is used, there is no risk of uneven distribution of phosphors and fillers that tend to occur at bent portions of the injection path. Therefore, in particular, when a plurality of light emitting devices are sealed at once, variation among individuals can be reduced.

In short, it is important to disperse the phosphor as evenly as possible in the resin, to cure the resin containing the phosphor while maintaining this state, and to cover the chip with the resin containing the phosphor with a uniform thickness.
(Dicing)
Subsequently, the substrate 1 on which the light emitting devices 20 are formed is individually separated by dicing.

  FIG. 5 is an outline view of a light-emitting device manufactured according to this embodiment. According to this, the outer surface of the chip 3 is covered with the first wavelength conversion unit 11 a with a substantially uniform thickness and sufficiently thicker than the thickness of the chip 3. That is, the top surface and the side surface of the first wavelength conversion unit 11a have surfaces parallel to the top surface and the side surface of the chip 3, respectively. Further, the portion along the side of the chip 3 has an inclined surface 17. Further, the yellow phosphor 13 is in a state of being dispersed in the first wavelength conversion unit 11a (indicated by white squares in FIG. 5C).

  FIG. 6 is a diagram illustrating characteristics of the light-emitting device. FIG. 6A shows the characteristics of the light emitting device produced according to the present embodiment, in which the wavelength conversion unit 11 a has the inclined surface 17 along the side of the chip 3. According to this, as compared with FIG. 6B, that is, the case where the inclined surface 17 is not provided, the fluctuation of the spectral distribution of the outgoing light due to the change of the outgoing angle θ is suppressed. In FIG. 6, the emission angle θ is 0 ° in the direction perpendicular to the surface of the substrate 1 and 90 ° in the parallel direction.

In this embodiment, a chip having a front electrode and a back electrode is used, but a flip chip 9 having a pair of electrodes on the surface can also be used. FIG. 8 is an external view of a light emitting device when a flip chip is used. The flip chip 9 is a chip in which, for example, a nitride semiconductor is stacked on a sapphire substrate 9c, and a pair of electrodes 9a and 9b is formed above the stack. Primary light is mainly transmitted from the sapphire substrate 9c side. Designed to take out. In the die bonding step, the electrodes 9a and 9b and the wiring patterns 2a and 2b can be opposed to each other and fixed with a conductive brazing material. According to this, since wire bonding is unnecessary, the wire does not get in the way when the chip is uniformly covered with the first wavelength conversion unit 11a, which is preferable.
(Second Embodiment)
FIG. 7 is an external view of a light emitting device according to the second embodiment of the present invention.

  In the present embodiment, the shape of the wavelength conversion section of the light emitting device according to the first embodiment is replaced with the shape of a truncated pyramid. Further, the phosphor to be dispersed in the resin is replaced with the yellow phosphor 13 and the red phosphor 14 and the green phosphor 15 are dispersed. Since other parts are the same as those in the first embodiment, different points will be described.

  FIG. 7A is an external view of a light emitting device in which the wavelength conversion unit 11a has a truncated pyramid shape. According to this embodiment, the longitudinal section of the wavelength conversion unit 11 a is trapezoidal, and the portion surrounding the side surface of the chip 3 has the inclined surface 17. At this time, in the portion where the inclined surface 17 surrounds the side surface of the chip 3, the thickness covering the outer surface of the chip 3 is not completely uniform. However, the intensity of the primary light emitted in an emission angle θ of approximately 90 °, that is, in a direction substantially parallel to the surface of the substrate 1 is relatively low, and it is considered that the effect of generating color unevenness is small.

  In addition, it is conceivable that the ratio of the primary light and the secondary light is compensated in this portion and the total reflection that occurs at the interface between the wavelength conversion unit and the outside is suppressed.

  FIG. 12 is a diagram showing an optical path of the light emitting device. The component of the emitted light by the primary light that has a relatively large emission angle θ and passes through the inclined surface 17 includes a component lp1 that is emitted through the thin portion of the wavelength converter and a component lp2 that is emitted through the thick portion. Therefore, lp1 has a high primary light ratio, and lp2 has a high secondary light ratio. Therefore, it is considered that the ratio of the primary light and the secondary light is compensated by mixing these components.

  In addition, the incident angle θi at the interface between the wavelength conversion unit 11a and the outside is reduced by inclining the side surface of the wavelength conversion unit 11a, and is incident at an angle closer to the interface. Therefore, it is conceivable that the intensity of the outgoing light that passes through the inclined surface 17 and is emitted becomes higher.

  These actions are considered to suppress the fluctuation of the spectral distribution with respect to the change in the emission angle θ.

  When it is assumed that the size of the chip is relatively small with respect to the wavelength conversion unit and can be approximated as a point light source, the thickness that the wavelength conversion unit covers the chip is preferably uniform in all directions. However, as the size of the chip increases, the above-mentioned premise is lost, and a component having a relatively large emission angle θ in primary light cannot be ignored. In such a case, by providing the shape of the wavelength converter shown in the present embodiment, it is possible to effectively suppress fluctuations in the spectrum distribution with respect to changes in the emission angle θ.

  In the present embodiment, light emission is made such that the length of one side of the base of the trapezoid is 2400 μm, the inclination angle of the inclined surface 17 with respect to the base of the trapezoid is 60 degrees, and the height of the trapezoid, that is, the thickness of the wavelength converter 11a is h = 800 μm. The device was prototyped. The chip 3 had a side length of 700 μm and a thickness of 100 μm. This light-emitting device exhibited characteristics substantially equivalent to the characteristics shown in FIG. 6A, and the effect of suppressing color unevenness was confirmed.

  FIG. 7B shows a red phosphor 14 and a green phosphor 15 (FIG. 7B) that absorb the primary light and emit red and green secondary light instead of the yellow phosphor 13 described above. It is sectional drawing of the light-emitting device which formed the wavelength conversion part 11a with the sealing resin 11 which disperse | distributed (it shows with a white circle and a white triangle). Thus, by having a wavelength conversion unit in which at least two kinds of phosphors are dispersed, a red component can be sufficiently included in the spectrum distribution of the emitted light, and the wavelength conversion unit has yellow fluorescence. Color rendering can be improved compared to the case of using only the body.

Similarly, a sealing resin 11 in which instead of blue light, a chip that emits primary light that is UV light, and phosphors that absorb primary light and emit red, green, and blue secondary light are dispersed. The same effect can be obtained even if the light emitting device having the wavelength conversion unit 11a formed by the above is configured.
(Third embodiment)
FIG. 1B is a diagram showing a manufacturing process of the light emitting device according to the third embodiment of the present invention.

In the present embodiment, the wavelength conversion unit of the light emitting device according to the first embodiment is configured by a plurality of types of wavelength conversion units. That is, the chip 3 is sealed with the first sealing resin 11 in which the red phosphor 14 is dispersed instead of the resin in which the yellow phosphor 13 is dispersed, and then the second phosphor in which the green phosphor 15 is dispersed. The sealing resin 12 is sealed so as to cover the first sealing resin 11. Since other parts are the same as those in the first embodiment, different points will be described.
(First resin sealing)
First, the first resin-sealed substrate is created by sealing the chip 3 with the first sealing resin 11 in which the red phosphors 14 are dispersed in advance.
(Second resin sealing)
Subsequently, the first resin-sealed substrate is further sealed with the second sealing resin 12 in which the green phosphor 15 is dispersed in advance, thereby performing the second resin sealing.

  In the second resin sealing, the first resin-sealed substrate is used instead of the die-bonded substrate, the green phosphor 15 is used as the phosphor, and the second cavity mold 41a is used. Since it is the same process as the first resin sealing, different parts will be described.

  FIG. 4B is an enlarged cross-sectional view showing the shape of the second main cavity 45 of the second cavity mold 41a. The second cavity mold 41a is the same as the first cavity mold 31a except that a second main cavity 45 is provided instead of the first main cavity 35.

  The inner wall surface of the second main cavity 45 has a shape that covers the periphery of the first wavelength converter 11a with a substantially uniform thickness. In addition, a second inclined surface 47 is provided in a portion facing the inclined surface 17 of the first wavelength conversion unit 11a. That is, the first resin-sealed substrate is set on the set surface 34, and the first wavelength conversion unit 11a is immersed in the second main cavity 45, and the top and side surfaces of the first wavelength conversion unit 11a are set. Are parallel to the inclined surface 17. By sealing the first wavelength conversion unit 11a with the second cavity mold 41a having the second main cavity 45 as described above, the periphery of the first wavelength conversion unit 11a is the second wavelength conversion unit. 12a is coated with a substantially uniform thickness.

  FIG. 5D is an external view of a light-emitting device manufactured according to this embodiment. The red phosphor 14 and the green phosphor 15 are dispersed in the first wavelength conversion unit 11a and the second wavelength conversion unit 12a, respectively (indicated by white circles and white triangles in FIG. 5D). According to this, since the distance through which the primary light passes through the first wavelength conversion unit 11a and passes through the second wavelength conversion unit 12a is uniform even when the emission angle θ changes, the emission angle Variations in the spectral distribution of emitted light due to changes in θ are suppressed.

  According to the present embodiment, since a plurality of wavelength conversion units including phosphors different from each other are separately stacked, the phosphors are not mixed between different layers, and the layers can be formed separately.

  In addition, after-curing in the first resin sealing is omitted, and only after-curing in the second resin sealing is performed, the process can be simplified.

  In addition, the order of arrangement of the wavelength converters is the order of the first wavelength converter 11a including the red phosphor 14 and the second wavelength converter 12a including the green phosphor 15 from the side close to the chip 3. Is preferred. That is, when a plurality of types of wavelength conversion units that absorb primary light that is blue light emitted by the chip 3 and emit different secondary light are provided, the wavelength conversion unit that emits secondary light having a relatively long wavelength is the chip. It is preferable to arrange in order from the side close to 3.

  The red phosphor 14 whose secondary light wavelength is centered at 640 nm can absorb green light whose wavelength is centered at 540 nm and blue light that is primary light. The green phosphor 15 whose secondary light wavelength is centered at 540 nm absorbs blue light, which is primary light, but is less likely to absorb light having a longer wavelength than green light emitted as secondary light. . Therefore, by arranging the wavelength conversion units in the order as described above, the secondary light emitted from the wavelength conversion unit arranged first is not absorbed by the wavelength conversion unit arranged later and is outside the light emitting device 20. Since the light is emitted, the efficiency can be increased.

  Similarly, a light emitting device including a chip that emits primary light that is UV light instead of blue light, and a plurality of types of wavelength converters that absorb primary light and emit different secondary light. The same effect can be obtained even if the arrangement of the wavelength conversion units is arranged in the order of the secondary light being red light, green light, and blue light from the side closer to the chip. .

In addition, the shape of the wavelength conversion part comprised by the several wavelength conversion part is not limited to the shape demonstrated in this Embodiment. For example, the shape of the truncated pyramid described in the second embodiment or a dome shape described later may be used.
(Fourth embodiment)
FIG. 9 is an external view of a light emitting device according to the fourth embodiment of the present invention.

  In the present embodiment, the shape of the wavelength conversion unit of the light emitting device according to the first embodiment is deformed into a dome shape. Further, the phosphor to be dispersed in the resin is replaced with the yellow phosphor 13 and the red phosphor 14 and the green phosphor 15 are dispersed. Since other parts are the same as those in the first embodiment, different points will be described.

  FIG. 9A is an external view of a light emitting device in which the wavelength conversion unit 11a has a dome shape. According to this embodiment, the chip 3 is covered with the wavelength conversion unit 11a having a dome-like shape with a circle drawn on the substrate 1 around the chip 3 as a bottom surface. As for the dimensions of the dome, for example, the diameter of the bottom surface can be φ = 2.5 mm and the height can be h = 0.8 mm.

  In a light emitting device in which a chip is coated with a resin, total reflection occurs at the interface between the resin and the outside, and it is known that a part of the emitted light cannot be extracted to the outside, resulting in a decrease in efficiency. . However, according to the present embodiment, since the interface is a curved surface, the total reflection of the outgoing light in which the primary light and the secondary light are mixed is suppressed, so that the light extraction efficiency is improved.

  In the present embodiment, the shape of the dome can be a hemispherical shape. As for the dimensions of the dome, for example, the diameter of the bottom surface can be φ = 2.5 mm, and the height can be h = 1.25 mm. Thereby, since the thickness with which the chip 3 is covered with the wavelength conversion unit 11a is uniform in all directions, the effect of suppressing the fluctuation of the spectrum distribution of the emitted light due to the change of the emission angle θ is high. Further, when the diameter of the dome is sufficiently larger than the size of the chip 3, the chip 3 is in a state close to a point light source, which is more effective.

  FIG. 9B shows a red phosphor 14 and a green phosphor 15 (FIG. 9B) that absorb the primary light and emit red and green secondary light instead of the yellow phosphor 13 described above. It is sectional drawing of the light-emitting device which formed the wavelength conversion part 11a with the sealing resin 11 which disperse | distributed (it shows with a white circle and a white triangle). Thus, it can be set as the structure which has a wavelength conversion part by which at least 2 or more types of fluorescent substance is disperse | distributed to resin.

  Similarly, a sealing resin 11 in which instead of blue light, a chip that emits primary light that is UV light, and phosphors that absorb primary light and emit red, green, and blue secondary light are dispersed. The same effect can be obtained even if the light emitting device having the wavelength conversion unit 11a formed by the above is configured.

  In any configuration, the color rendering can be improved for the same reason as in the second embodiment.

In these embodiments, the outer surface of the wavelength conversion unit is coated with a transparent resin, and the coating is given a predetermined shape to protect the wavelength conversion unit from the outside air and to provide a lens function. it can.
(Fifth embodiment)
FIG. 10 is a diagram showing the structure of a surface light source and a flat panel display. In FIG. 10, the description of the wiring on the mounting substrate 62 is omitted.

  The surface light source 61 includes a mounting substrate 62 and the light emitting device 20 manufactured according to any one of the first to fourth embodiments. Preferably, the surface light source 61 has a pillar 65 from the surface of the mounting substrate 62, for example, 10 mm to 20 mm. A diffusing plate 63 is provided at an interval. A plurality of light emitting devices 20 are disposed at predetermined positions on the surface of the mounting substrate 62.

  The light emitted from each light emitting device 20 is diffused by the diffusion plate 63 and emitted forward, but it appears as if the entire surface is emitting light through the diffusion plate 63. The light emitting device 20 has a small variation in the spectral distribution with respect to the change in the radiation angle θ, and the variation in the spectral distribution among the individual light emitting devices is small, so that in-plane color unevenness can be suppressed. Thus, the surface light source 61 in which the in-plane color unevenness is suppressed can be suitably used as the backlight of the flat panel display 66, and the display quality can be improved. For example, as shown in FIG. 10C, a display device having a structure in which a liquid crystal display element 64 is disposed on the light emitting surface side of the surface light source 61 and the liquid crystal display element 64 is irradiated from the back surface can be configured. .

It is a figure which shows the manufacturing process of the light-emitting device of this invention. It is the top view and sectional drawing which show the die-bonded board | substrate. It is the perspective view which shows the structure of a metal mold | die, and sectional drawing which shows a state when a board | substrate is set to a metal mold | die. It is an expanded sectional view showing the shape of the 1st main cavity and the 2nd main cavity. It is an external view of a light-emitting device. It is a figure which shows the characteristic of a light-emitting device. It is an external view of the light-emitting device which is 2nd Embodiment. It is an external view of the light-emitting device when a flip chip is used. It is an external view of the light-emitting device which is 4th Embodiment. It is a figure which shows the structure of a surface light source and a flat panel display. It is a chromaticity diagram showing a state where the emission angle θ is changed. It is a figure which shows the optical path of a light-emitting device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 3 Chip 4 Wire 9 Flip chip 11 1st sealing resin 11a 1st wavelength conversion part 12 2nd sealing resin 12a 2nd wavelength conversion part 13 Yellow fluorescent substance 14 Red fluorescent substance 15 Green fluorescent substance 17 Inclined surface 20 Light emitting device 31 Mold 31a First cavity mold 31b Base mold 32 Bathtub portion 34 Set surface 35 First main cavity 37 First inclined surface 41a Second cavity mold 45 Second main cavity 47 Second Inclined surface 61 Surface light source 63 Diffuser plate 64 Liquid crystal display element 65 Pillar 66 Flat panel display

Claims (9)

A substrate,
A semiconductor light emitting device that is die-bonded to the substrate and emits primary light;
A light-emitting device that covers the semiconductor light-emitting element and has a wavelength conversion unit that absorbs the primary light and emits secondary light,
The wavelength conversion unit has a structure in which a phosphor is dispersed in a resin, has a truncated pyramid shape that is trapezoidal in a longitudinal section, and a side surface of the semiconductor light emitting element is surrounded by an inclined surface. Light emitting device. A substrate,
A semiconductor light emitting device that is die-bonded to the substrate and emits primary light;
A light-emitting device that covers the semiconductor light-emitting element and has a wavelength conversion unit that absorbs the primary light and emits secondary light,
The wavelength conversion unit is a light emitting device in which a phosphor is dispersed in a resin and has a dome shape.   3. The light emitting device according to claim 1, wherein at least two types of the phosphors are dispersed in the wavelength conversion unit.   The wavelength converter includes a plurality of types of the wavelength converters that absorb the primary light and emit different secondary lights, and the wavelength converter that emits secondary light having a relatively long wavelength is the semiconductor light emitting device. The light-emitting device according to claim 1, wherein the light-emitting device is arranged in order from a side closer to the element.   5. A surface light source comprising: the light emitting device according to claim 1; and a mounting substrate, wherein the plurality of light emitting devices are arranged on a surface of the mounting substrate.   6. A display device comprising: the surface light source according to claim 5; a liquid crystal display element; and a structure in which the surface light source irradiates the liquid crystal display element from a back surface. A step of dispersing a phosphor in a resin and preparing a resin containing the phosphor;
Injecting the phosphor-containing resin into a cavity of a mold;
A method of manufacturing a light-emitting device comprising sequentially setting a substrate on which a semiconductor light-emitting element is die-bonded to the mold,
An inner wall surface of the cavity has a truncated pyramid shape that is trapezoidal in a longitudinal section, and the semiconductor light emitting element has a structure in which a side surface of the semiconductor light emitting element is surrounded by an inclined surface in a state where the semiconductor light emitting element is immersed in the cavity. A method of manufacturing a light emitting device. A step of dispersing a phosphor in a resin and preparing a resin containing the phosphor;
Injecting the phosphor-containing resin into a cavity of a mold;
A method of manufacturing a light-emitting device comprising sequentially setting a substrate on which a semiconductor light-emitting element is die-bonded to the mold,
An inner wall surface of the cavity has a dome shape, and the semiconductor light emitting element is surrounded by the inner wall surface in a state where the semiconductor light emitting element is immersed in the cavity. Production method. The mold includes a cavity mold having the cavity and a base mold having a pressure surface, and the phosphor-containing resin is injected into the cavity in a state where the cavity mold and the base mold are separated from each other. Process,
The method for manufacturing a light emitting device according to claim 7, further comprising a step of pressing the cavity mold and the pressing surface of the base mold so as to face each other.