JP4254276B2 - Light emitting device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light-emitting device that absorbs light emitted from a light-emitting diode (hereinafter referred to as “LED”) with a phosphor, converts the light into light having a different wavelength, and emits the light. The present invention relates to a light emitting device that is large and has excellent light collecting properties.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a light emitting device that emits light emitted from an LED chip by converting the wavelength of the light with a phosphor (see, for example, Patent Document 1).
[0003]
FIG. 9 shows a light emitting device disclosed in Patent Document 1, and FIG. 9A is a longitudinal sectional view. The light emitting device 10 electrically connects the lead frames 11A and 11B, the cup 12 formed on the lead frame 11A, the LED 13 held in the cup 12, and the electrode portion of the LED 13 and the lead frames 11A and 11B. A bonding wire 14 for sealing, a sealing portion 15 for sealing the LED 13 provided in the cup 12, and a bullet-shaped epoxy resin 16 having light transmittance and sealing the whole.
[0004]
FIG. 9B shows a partially enlarged view of the cup 12. The LED 13 is sealed with a transparent spacer 15A, and a fluorescent material 15B is provided in a layer on the surface of the transparent spacer 15A.
[0005]
According to such a configuration, uniform and uniform white light can be obtained by uniformly illuminating the fluorescent material 15B.
[0006]
FIG. 10 partially shows another configuration of the light-emitting device disclosed in Patent Document 1. In this configuration, the LED 13 mounted on the substrate 17 by the transparent spacer 15A formed by dropping an ultraviolet curable resin on the LED 13 and the fluorescent material 15B formed in a layer by being dropped on the surface of the transparent spacer 15A. Is sealed in a hemispherical shape.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-077723 (FIGS. 1, 3, and 4)
[0008]
[Problems to be solved by the invention]
However, according to the conventional light emitting device, since a resin or a fluorescent material is dropped around the LED, there is a problem that the sealing shape and thickness cannot be provided with high accuracy. In addition, when the LED is sealed in a hemisphere with resin, the dropped fluorescent material flows and accumulates around the resin, and the light extraction efficiency is lowered by absorbing light at that portion. is there.
[0009]
Further, in FIG. 9B, since the fluorescent material 15B emits light, there is a problem that the light emitting area becomes approximately 10 times, and it becomes difficult to obtain the light collecting effect by the light collecting optical system. That is, as shown in FIG. 11A, when the light emitted from the light source 19 is condensed by the condensing optical system 18, the light emission area of the light source 19 is small and the light L is sufficiently collected when it can be regarded as a point light source. To be lighted. On the other hand, as shown in FIG. 11 (b), if the light emitting area of the light source 19 is large, sufficient condensing cannot be performed, resulting in a decrease in condensing degree that cannot be regarded as a point light source.
[0010]
Accordingly, an object of the present invention is to provide a light-emitting device that can increase the luminous intensity by preventing the light source size from increasing, reducing the light absorption loss, and irradiating the light condensed in a desired direction and range. Is to provide.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a semiconductor light emitting element that emits light of a predetermined wavelength, and an external lens.
Said external lens is a recess-like element accommodating portion for accommodating a pre-Symbol light-emitting portion, a phosphor layer is excited by light emitted from formed on an inner surface of the element housing portion and the light-emitting portion And a condensing optical shape for condensing the light emitted from the phosphor layer , and the element housing portion condenses the light emitted from the phosphor layer in a spot shape by the condensing optical shape. A light-emitting device having a size is provided.
[0012]
Semiconductors light emitting element section may also be used flip chip type LED elements which emit light from the light emitting surface provided on the opposite side to the mounting surface.
[0013]
It is preferable that the element accommodating portion is provided close to the outer shape of the semiconductor light emitting element portion. Further, the semiconductor light emitting element portion may be formed by regularly arranging a plurality of LED elements, or may be formed by regularly arranging a plurality of LED elements having different emission wavelengths.
[0014]
According to such a configuration, the phosphor portion is arranged with a uniform thickness in the vicinity of the semiconductor light emitting element portion, thereby suppressing an increase in the apparent light source size due to excitation light emission of the phosphor. The amount of light absorption is reduced.
[0015]
The present invention, in order to achieve the above object, Engineering and more mounting surfaces that form a electrode extending in a direction perpendicular to the optical axis of the light-emitting portion of a metal material,
And as factories that implements a semiconductor light emitting element to the mounting surface of the electrode,
Forming an external lens having a flat surface that comes into contact with the mounting surface, and a hollow element housing portion that is formed on the flat surface and houses the semiconductor light emitting element portion when fixed to the electrode;
Forming a phosphor layer of the thin layer along the shape of the element housing portion of the external lens,
Provide a method of manufacturing a light emitting device characterized by having said Cheng Hao you positioning and fixing the external lens and the said electrode so that the semiconductor light emitting element is surrounded by the phosphor layer of the element receiving part To do.
[0016]
The element accommodating portion is preferably formed with the phosphor layer by spraying a phosphor material after molding the light-transmitting resin.
[0017]
As the electrode, a lead electrode provided on the surface of the highly heat-conductive submount material or a copper foil electrode provided on the surface of the base material having high heat conductivity via an insulating layer can be used. The semiconductor light emitting element is preferably flip-chip bonded to the electrode.
[0018]
According to such a configuration, the light transmission part can be manufactured in a separate process, so that the productivity is excellent, and the phosphor part having a uniform thickness is accurately arranged in the vicinity of the semiconductor light emitting element part.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
1A and 1B show a light emitting device according to a first embodiment of the present invention, in which FIG. 1A is a longitudinal sectional view, FIG. 1B is a partially enlarged view of an LED element, and FIG. A cross section is shown.
[0020]
In the following description, as a definition of light collection, in addition to light collection in a spot shape in the optical axis direction, light collection in a direction perpendicular to the optical axis or a direction having a predetermined angle with respect to the optical axis Concentration of light is also included.
[0021]
As shown in FIG. 1A, the light emitting device 1 is provided on the surface of the leads 2A and 2B formed of a metal material such as copper having excellent thermal conductivity, and the leads 2A and 2B on the element mounting side. Submount 3 having wiring patterns 3A and 3B, LED element 4 mounted on wiring patterns 3A and 3B, and lens 5 externally fixed to leads 2A and 2B so as to surround LED element 4 Have
[0022]
The submount 3 is made of a high thermal conductivity material such as AlN, and the LED element 4 is flip-chip bonded to the copper foil wiring patterns 3A and 3B formed on the surface via the bumps 4A. The wiring pattern 3A is electrically connected to the lead 2A, and the wiring pattern 3B is electrically connected to the lead 2B via a via hole (not shown).
[0023]
The LED element 4 is formed to emit light in a blue color of 450 nm to 480 nm using, for example, a gallium nitride compound semiconductor such as GaN, GaAlN, InGaN, InGaAlN, or ZnSe (zinc selenide). This LED element 4 emits light mainly from the side of the sapphire substrate formed on the side opposite to the electrode formation surface, and has a chip size of 1000 × 1000 μm. Since the element structure of the blue LED is a well-known technique, a detailed description thereof is omitted.
[0024]
The lens 5 is formed in a cannonball shape by injection molding a light transmissive resin such as an epoxy resin, and is positioned and fixed at a predetermined position with respect to the leads 2A and 2B on which the LED element 4 is mounted. ing. Although this positioning is not shown, the positioning is performed based on the concave-convex fitting between the concave portions formed in the leads 2A and 2B and the convex portions formed in the lens 5. In addition, you may make it fix with sufficient position accuracy by another positioning method.
[0025]
Further, as shown in FIG. 1B, the lens 5 has a hollow element housing portion 50 that houses the LED element 4 when positioning and fixing to the leads 2 </ b> A and 2 </ b> B, and the inner peripheral surface of the element housing portion 50. Is provided with a thin phosphor layer 5A. As shown in FIG. 1 (c), the element accommodating portion 50 is formed with a size that makes the gap 5 </ b> B formed between the element accommodating portion 50 and the LED element 4 as small as possible. The phosphor layer 5A is made of Ce: YAG (yttrium, aluminum, garnet) that is excited by the blue light having the above-described wavelength to emit yellow light.
[0026]
In order to manufacture such a light emitting device 1, first, leads 2A and 2B are formed by punching a metal material. In addition, an indentation for positioning is formed during punching of the leads 2A and 2B. Next, the submount 3 is formed of a high thermal conductivity material on the element mounting side of the leads 2A and 2B. Next, predetermined circuit patterns 3A and 3B made of copper foil are formed on the surface of the submount 3. Next, the LED element 4 is flip-chip bonded to the predetermined positions of the circuit patterns 3A and 3B via the bumps 4A.
[0027]
The lens 5 is formed in a separate process. First, a lens 5 having an element accommodating portion 50 is injection molded by filling a mold corresponding to the lens shape with a light transmissive resin. In addition, the positioning convex portions are molded together during resin molding. Next, the phosphor layer 5A is formed by thinly applying a phosphor to the element housing portion 50.
[0028]
Next, they are positioned and fixed so that the convex portions provided on the lens 5 and the concave portions provided on the leads 2A and 2B are fitted. At this time, a transparent silicon resin is injected into the element housing portion 50. Next, the lens 2 is put on the leads 2A and 2B to be bonded and fixed, and the LED element 4 is sealed with silicon.
[0029]
The operation of the light emitting device according to the first embodiment will be described below.
[0030]
A drive unit (not shown) applies a drive voltage to the leads 2A and 2B. The LED element 4 emits light based on the driving voltage and emits blue light. Blue light emitted from the LED element 4 is applied to the phosphor layer 5A. The phosphor layer 5A is excited based on blue light and emits yellow light. The yellow light and the blue light are mixed in the phosphor layer 5A to become white light. The white light travels through the lens 5, is collected at the shell-shaped portion, and is emitted outside the lens 5. The emitted white light is condensed in a predetermined irradiation range with a similarity ratio determined by the size of the light source unit and the optical system shape.
[0031]
According to the first embodiment described above, the following effects are obtained.
(1) Since the element housing portion 50 is provided in the external lens 5 and the phosphor layer 5A is thinly provided on the inner peripheral surface of the element housing portion 50 so as to integrally surround the LED element 4, the phosphor layer It becomes possible to form 5A uniformly thinly. Further, since the phosphor layer 5A having a uniform thickness can be formed, it is possible to prevent a decrease in luminous intensity due to light absorption. Moreover, since the size expansion of the light source due to the thickness of the phosphor layer 5A can be minimized, the light can be condensed in a spot shape by the condensing optical system, and the luminous intensity in a predetermined irradiation range can be increased. it can.
(2) Further, even when the LED element 4 having a large size (for example, about 1000 μm square) is used as the light source, it is possible to prevent light source size from being enlarged by being covered with the phosphor layer 5A and to secure the light collecting property. It becomes possible.
(3) Since the lens 5 is formed separately and is positioned and fixed with respect to the leads 2A and 2B, the LED element 4 and the phosphor layer 5A are arranged in an appropriate positional relationship, which is desired. The light can be collected with high accuracy in the irradiation direction and irradiation range. Moreover, it becomes possible to selectively attach the lens 5 having a shape corresponding to the application and light condensing property.
(4) In the method of providing the lens 5 with the phosphor layer 5A in the element housing portion 50, a formation method in which the layer thickness is made uniform and thin can be selected. Therefore, even when an expensive phosphor is used, the amount used is reduced. It is possible to reduce the manufacturing cost.
(5) Since the LED element 4 is mounted on the leads 2A and 2B via the submount 3 having high thermal conductivity, the heat dissipation is improved, and there is a margin for increasing the output of the light emitting device in response to the demand for increasing the luminous intensity. Can respond.
[0032]
FIG. 2 shows an element housing portion of the lens according to the second embodiment. In this lens 5, an element housing portion 50 that surrounds the LED element 4 is formed in a rectangular shape that is substantially the same as the outer shape of the LED element 4. In the following description, the same reference numerals are assigned to portions having the same configuration as that of the first embodiment, so that the duplicate description is omitted.
[0033]
According to the second embodiment described above, since the gap 5B between the LED element 4 and the phosphor layer 5A can be made smaller, the increase in the light source size can be more effectively suppressed, and the light is thereby emitted. The light condensing property can be further enhanced.
[0034]
3A and 3B show a light emitting device according to a third embodiment, wherein FIG. 3A is a longitudinal sectional view, FIG. 3B is a partially enlarged view of an LED element, and FIG. 3C is a sectional view taken along line BB in FIG. .
[0035]
As shown in FIGS. 3A and 3B, the light emitting device 1 surrounds the LED element 4 mounted on the wiring patterns 3A, 3B, and 3C of the submount 3 and the LED element 4, respectively. The lens 5 is externally fixed to the leads 2A and 2B.
[0036]
As shown in FIG. 3C, the LED element 4 includes a red LED element 40 that emits red light and eight blue LED elements 41 that are arranged around the red LED element 40. , And 3C, each LED element has a chip size of 300 × 300 μm.
[0037]
The phosphor layer 5A is made of Ce: YAG that is excited based on the blue light emitted from the blue LED element 41 and emits yellow light.
[0038]
According to the third embodiment described above, in addition to the preferable effects of the first embodiment, blue light emitted from the blue LED element 41 and yellow emitted from the phosphor layer 5A excited by the blue light. White light can be obtained by mixing with light, and white light with high color rendering can be obtained by adding red light emitted from the red LED element 40.
[0039]
As another configuration in which a plurality of LED elements are provided, for example, a fluorescent LED in which an ultraviolet LED element 41 is arranged around a red LED element 40 instead of the blue LED element 41 and red, blue, and green phosphors are mixed. White light may be obtained based on passing ultraviolet light through the body layer 5A. Further, nine blue LED elements 41 may be provided instead of the red LED elements 40.
[0040]
In the above-described embodiment, the configuration in which the wavelength of the light of the LED element 4 is converted by the phosphor has been described. However, for example, a light diffusion layer is formed on the inner peripheral surface of the element housing portion 50 to emit from the LED element 4. The light diffused by the light diffusion layer may be used. According to this, it is possible to approximate a plurality of light emitting elements to a continuous light source, and it is possible to reduce the light source size.
[0041]
4A and 4B show a light emitting device according to a fourth embodiment, where FIG. 4A is a longitudinal sectional view, and FIG. 4B is a partially enlarged view of an LED element.
[0042]
As shown in FIGS. 4A and 4B, the light emitting device 1 includes an insulating layer 6A, a base material 6B made of a good thermal conductor such as aluminum, a copper foil provided on the surface of the insulating layer 6A, and the like. The substrate 6 having the wiring patterns 3A and 3B is used, and the LED elements 4 having a size (300 × 300 μm) smaller than the LED elements 4 described in the first embodiment are flip-chiped on the wiring patterns 3A and 3B. The bonded configuration is different from that of the first embodiment.
[0043]
According to the fourth embodiment described above, since the substrate 6 excellent in heat dissipation is used in addition to the preferable effects of the first embodiment, the heat generated when the LED element 4 is turned on is efficiently transmitted through the substrate 6. It is possible to dissipate well, and it is possible to cope with an increase in the output of the LED element 4. Even when the size of the LED element 4 is reduced, the phosphor layer 5A is thin, so that it is possible to prevent light from being shielded. Further, by using the small LED element 4, it is possible to collect light in a spot size of a smaller size by the condensing optical system, and it is possible to improve the light intensity in a predetermined irradiation range.
[0044]
FIG. 5 shows a longitudinal section of a light emitting device according to the fifth embodiment.
[0045]
In the light emitting device 1, the LED element 4 having a size of 300 × 300 μm is face-up bonded to the wiring pattern 3A of the substrate 6 described in the fourth embodiment, and the electrode portion of the LED element 4 and the wiring patterns 3A and 3B Are electrically connected by a bonding wire 7.
[0046]
The lens 5 has an element accommodating portion 50 formed in a dome shape so as to surround the LED element 4 and the bonding wire 7, and a phosphor layer 5 </ b> A formed in a thin layer on the inner peripheral surface of the element accommodating portion 50. Is provided. A transparent silicon resin (not shown) is injected inside the element housing portion 50.
[0047]
According to the fifth embodiment described above, even when the LED element 4 is face-up joined, the size expansion of the light source can be suppressed, the luminous intensity can be increased, and the light collecting property can be improved. In addition, it is preferable that the dome shape of the element accommodating part 50 is formed in the minimum radius size which can protect the bonding wire 7, for example, you may form in the cone shape.
[0048]
In each of the above-described embodiments, the light emitting device in which the phosphor layer 5A is thinly formed in the element housing portion 50 formed in the lens 5 in a concave shape has been described. However, for example, if the phosphor layer 5A can be formed compactly and thinly, The lens 5 and the phosphor layer 5A can be provided separately.
[0049]
FIG. 6 shows a longitudinal section of a light emitting device according to the sixth embodiment.
[0050]
The light emitting device 1 includes an LED element 4 face-up bonded to a wiring pattern 3A of a substrate 6, a light-transmitting resin cap 8 provided separately so as to surround the LED element 4 in a dome shape, and a cap 8 The lens 5 is integrally formed with the substrate 6 with a gap 5C between the element housing portion 50 and the phosphor layer 5A. A transparent silicon resin is injected inside the cap 8.
[0051]
According to the sixth embodiment described above, since the lens 5 and the phosphor layer 5A can be formed in separate steps, the formation thickness when the phosphor layer 5A is formed on the surface of the cap 8 can be easily controlled. Can do. The shape of the cap 8 is not limited to the illustrated dome shape, and may be formed in a rectangular shape that can cover the LED element 4 that is flip-chip bonded.
[0052]
Moreover, although the above-mentioned condensing optical system condenses light in the optical axis direction of the light source, for example, it can be applied to a light emitting device that emits light in a direction orthogonal to the optical axis of the light source.
[0053]
FIG. 7 shows a longitudinal section of a light emitting device according to a seventh embodiment.
[0054]
The light emitting device 1 is provided with a horizontal emission type lens 5 that emits light emitted from the LED element 4 in a horizontal direction orthogonal to the optical axis, instead of the bullet-shaped lens 5 shown in the fourth embodiment. Have a configuration. The lens 5 is integrally provided with a reflection surface 5D that totally reflects the light emitted from the LED element 4.
[0055]
According to the seventh embodiment described above, by emitting the light reflected by the reflecting surface 5D in the horizontal direction, the light extraction efficiency in the direction orthogonal to the optical axis is improved, and the lens 5 is directed toward the side surface. Condensation is improved. This can increase the light intensity in a predetermined irradiation range in the horizontal direction.
[0056]
In addition, the condensing optical system can be applied to a light emitting device that emits light through a configuration in which a transmission optical system and a reflection optical system are combined.
[0057]
FIG. 8 shows a longitudinal section of a light emitting device according to the eighth embodiment.
[0058]
The light emitting device 1 includes an LED element 4 face-up bonded on a substrate 6, a reflective lens 5 made of a light-transmitting material such as silicon resin provided around the LED element 4, and a reflective film of the lens 5. And a light shielding plate 9 having a slit 9A for allowing the light reflected by 5E to pass therethrough.
[0059]
The lens 5 is formed to have a hemispherical outer shape, and has a reflective film 5E such as aluminum formed on its surface by a thin film formation technique such as sputtering.
[0060]
In addition, the lens 5 has a space 50A that accommodates the substrate 6 at the center, and the tip of the space 50A is formed in a dome shape. In addition, the phosphor layer 5A is formed in a thin layer on the inner peripheral surface of the tip portion.
[0061]
The light emitted from the LED element 4 is emitted to the lens 5 through the phosphor layer 5A. The light transmitted through the lens 5 is radiated to the outside of the lens 5 through the slit 9A by being reflected by the reflective film 5E.
[0062]
According to the above-described eighth embodiment, even when light transmitted through the lens 5 and reflected by the light reflecting film 5E is emitted from the slit 9A, the light condensing property is good due to the small light source size. Can be granted.
[0063]
In each of the above-described embodiments, the configuration in which the element accommodating portion 50 is provided in the lens 5 has been described. However, the element accommodating portion 50 is provided in a light transmissive member different from the lens 5, and the light transmissive member and the lens 5 are provided. And a condensing optical system may be configured.
[0064]
【The invention's effect】
As described above, according to the light emitting device of the present invention, the element housing portion is provided in the external lens, and the phosphor layer is thinly provided on the inner peripheral surface of the element housing portion so as to integrally surround the LED element. In addition, the light source size can be prevented from being increased, the light absorption loss can be reduced, the luminous intensity can be increased, and the light condensed in a desired direction and range can be irradiated.
[Brief description of the drawings]
1A and 1B show a light emitting device according to a first embodiment of the present invention, in which FIG. 1A is a longitudinal sectional view, FIG. 1B is an enlarged partial sectional view of an LED element portion, and FIG. It is a fragmentary sectional view in the AA section.
FIG. 2 is a partial cross-sectional view of a light emitting device according to a second embodiment.
3A and 3B show a light emitting device according to a third embodiment, in which FIG. 3A is a longitudinal sectional view, FIG. 3B is an enlarged partial sectional view of an LED element portion, and FIG. It is a fragmentary sectional view in B section.
4A and 4B show a light emitting device according to a fourth embodiment, in which FIG. 4A is a longitudinal sectional view, and FIG. 4B is an enlarged partial sectional view of an LED element portion.
FIG. 5 is a longitudinal sectional view of a light emitting device according to a fifth embodiment.
FIG. 6 is a longitudinal sectional view of a light emitting device according to a sixth embodiment.
FIG. 7 is a longitudinal sectional view of a light emitting device according to a seventh embodiment.
FIG. 8 is a longitudinal sectional view of a light emitting device according to an eighth embodiment.
FIG. 9A is a longitudinal sectional view showing a conventional light emitting device.
(B) is the elements on larger scale of LED of (a).
FIG. 10 is a partial cross-sectional view showing another configuration of a conventional light emitting device.
FIG. 11A is a diagram showing the light collecting property when the light source size is small.
(B) is a figure which shows the condensing property in case a light source size is large.
[Explanation of symbols]
1, light emitting device 2A, lead 2B, lead 3, submount 3A, circuit pattern 3A, wiring pattern 3B, wiring pattern 4A, bump 4, LED element 5, lens 5A, phosphor layer 5B, gap 5C, gap 5D, reflection Surface 5E, reflective film 6, substrate 6A, insulating layer 6B, base material 7, bonding wire 8, cap 8, translucent resin portion 9, light shielding plate 9A, slit 10, light emitting device 11A, lead frame 12, cup 14, Bonding wire 15, sealing part 15A, transparent spacer 15B, fluorescent material 16, epoxy resin 17, substrate 18, condensing optical system 19, light source 40, element 41, element 50, element housing part 50A, space

Claims (5)

A semiconductor light emitting element that emits light of a predetermined wavelength, and an external lens,
Said external lens is a recess-like element accommodating portion for accommodating a pre-Symbol light-emitting portion, a phosphor layer is excited by light emitted from formed on an inner surface of the element housing portion and the light-emitting portion And a condensing optical shape for condensing the light emitted from the phosphor layer , and the element housing portion condenses the light emitted from the phosphor layer in a spot shape by the condensing optical shape. A light-emitting device having a size . The light emitting device according to claim 1, wherein the semiconductor light emitting element unit is a flip chip type LED element that emits the light from a light emitting surface provided on the opposite side to the mounting surface. The element accommodating portion, the light emitting device according to claim 1 or 2, characterized in that provided in close proximity along the outer shape of the semiconductor light emitting element section. The semiconductor light emitting element portion, light-emitting device according to any one of claims 1 to 3, characterized in that it is formed by arranging a plurality of LED elements regularly. The semiconductor light emitting element portion, light-emitting device according to any one of claims 1 to 3, characterized in that a plurality of different LED elements emission wavelengths are formed by regularly arranged.

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