WO2014132542A1 - Light emitting element - Google Patents

Abstract

A light emitting element (100) is provided with: an LED element (1); a resin section, which contains phosphor, and which seals the LED element, said phosphor absorbing a part of light emitted from the LED element, performing wavelength conversion, and emitting the light; and a reflecting film (3), which contains an inorganic oxide, and which is formed on the surface of the resin section. The reflecting film has wavelength dependence in light transmission characteristics, and a refractive index of the reflecting film is larger than that of the resin section. As a result, the light emitting element capable of efficiently outputting white light having desired chromatic characteristics is provided.

Description

Light emitting element

The present invention relates to a light emitting element. More specifically, the present invention relates to a light emitting element that can emit white light adjusted to a desired chromaticity with high light extraction efficiency.

White light emitting devices using semiconductor light emitting devices are expected to be applied to the next generation of general lighting and bulbs such as liquid crystal backlights, and tube markets such as fluorescent tubes and cold cathode tubes. Such a white light emitting element is obtained by coating a light emitting diode chip with a resin containing phosphor, etc., and light from a phosphor excited by light from the light emitting diode chip and light from the light emitting diode chip. To obtain white light.

In recent years, with the improvement in performance of individual white light-emitting elements due to the development of technologies such as blue light-emitting diodes and phosphors used in white light-emitting elements, white light-emitting elements that surpass luminous efficiency such as fluorescent lamps and cold cathode tubes are being commercialized. is there.

However, these white light emitting elements still have large chromaticity variations compared to chromaticity variations such as fluorescent lamps and cold cathode fluorescent lamps. Is required. Therefore, various structures for reducing variations in chromaticity have been proposed (Patent Documents 1 to 4).

Patent Document 1 discloses a structure that improves the accuracy of chromaticity by using a plurality of LED chips and making the combination of chromaticity of each LED chip a predetermined combination. However, in this structure, when a module is used, chromaticity variation occurs due to variations in the amount of phosphor of each LED chip.

Therefore, Patent Documents 2 to 4 disclose techniques for color matching in a separate process in a modularized state.

In Patent Document 2, the phosphor layer for chromaticity adjustment containing the second phosphor provided in the outer layer in the light emitting direction than the phosphor-containing resin layer containing the first phosphor. A configuration formed in a dot shape is disclosed, and it is disclosed that the color is finely adjusted by the phosphor layer for chromaticity adjustment.

Patent Document 3 discloses a light-emitting element containing a phosphor and having a light scattering portion formed on at least a part of the surface of a sealing resin portion covering a light-emitting diode chip, and the light scattering portion is disposed therein. Thus, it is disclosed that the efficiency of quantum conversion by a phosphor is improved.

Patent Document 4 has an LED element and a sealing material containing a phosphor in a transparent resin, and the sealing material is disposed in the periphery of the LED element, and the surface of the sealing material An LED light source having a transparent thin film with a refractive index different from the refractive index of the encapsulant is disclosed.

Japanese Patent Publication “Japanese Unexamined Patent Publication No. 2011-3594 (January 6, 2011)” Japanese Patent Publication “Japanese Patent Laid-Open No. 2010-186968 (Released on August 26, 2010)” Japanese Patent Publication “JP 2009-130301 A” (published on June 11, 2009) Japanese Patent Publication “Japanese Patent Laid-Open No. 2010-16029 (published on Jan. 21, 2010)”

However, since the technique disclosed in Patent Document 2 requires a process of forming the chromaticity adjusting phosphor layer in a dot shape, it is difficult to accurately configure the chromaticity adjusting phosphor layer. Therefore, there is a problem that it is difficult to finely adjust the color in practice.

On the other hand, methods disclosed in Patent Documents 3 and 4 can be used to easily and accurately construct the phosphor layer.

However, in the method disclosed in Patent Document 3, the ratio of the fluorescence emitted from the phosphor being scattered by the light scattering portion and other phosphors, resulting in a loss due to multiple scattering, increases the light extraction efficiency. There is a problem that will decrease.

In the method disclosed in Patent Document 4, it is disclosed that the refractive index of the transparent thin film is smaller than the refractive index of the resin, or that the transparent thin film is a multilayer film. When the refractive index of a transparent thin film is smaller than the refractive index of resin, the light emission from resin to air becomes favorable.

However, since the refractive index of a general resin is 1.4 to 1.8, and a substance having a refractive index smaller than this range is very rare, the combination of a transparent thin film and a resin is also practical. There is no combination. Therefore, there is a problem that it is difficult to give wavelength dependency to the transmission characteristics of light passing through the transparent thin film.

In addition, when the transparent thin film is a multilayer film, there are problems that the control of the film thickness is complicated and that the number of manufacturing steps increases, resulting in a decrease in productivity.

The present invention has been made in view of the above-described problems, and has an object of being able to finely adjust chromaticity while maintaining light utilization efficiency with a simple structure and having desired chromaticity characteristics. An object of the present invention is to provide a light emitting device capable of emitting white light and a method for manufacturing the same.

In order to solve the above-described problems, a light-emitting element according to one embodiment of the present invention includes an LED element and a phosphor that absorbs part of light emitted from the LED element and emits light by wavelength conversion. A resin part that seals the LED element; and a reflective film that contains an inorganic oxide and is formed on the surface of the resin part. The reflective film is formed on the surface of the resin part. Therefore, the transmission characteristic of the outgoing light emitted from the reflective film has a wavelength dependency, and the refractive index of the reflective film is larger than the refractive index of the resin portion.

The light-emitting element according to one embodiment of the present invention has an effect that white light having desired chromaticity characteristics can be obtained efficiently and at low cost.

1 is a schematic sectional view of a light emitting device according to a first embodiment of the present invention. FIG. 6 is a chromaticity diagram illustrating variation in chromaticity depending on the presence or absence of a reflective film in the light emitting device according to the present invention. It is a schematic sectional structure figure of the light emitting element concerning the 2nd Embodiment of this invention. It is a schematic diagram which shows the outline of the process of the manufacturing method of the light emitting element concerning this invention. It is a figure which shows the result of having measured the wavelength dependence of the light emitting element in the Example of this invention. It is a figure which shows the result of having measured the wavelength dependence of the light emitting element in the comparative example of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected about the member which shows the same function and an effect | action. Unless otherwise specified, “A to B” representing a numerical range means “A or more (including A and greater than A) and B or less (including B and less than B)”.

The light-emitting element according to the present invention includes an LED element, a phosphor that absorbs part of the light emitted from the LED element, converts the wavelength, and emits light, and a resin that contains the phosphor and seals the LED element. And a reflective film that contains an inorganic oxide and is formed on the surface of the resin part, and the reflective film is formed on the surface of the resin part, whereby the reflective film The wavelength dependence of the transmission characteristics of the outgoing light emitted from the outside to the outside occurs, and the refractive index of the reflective film is larger than the refractive index of the resin portion.

<First Embodiment>
(Light-emitting device according to the present invention)
A light emitting device according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic sectional view of a light emitting device 100 according to the first embodiment.

As shown in FIG. 1, the light emitting element 100 includes an LED element 1, a phosphor-containing resin layer 2 (also referred to as “resin portion” in the present specification), a reflective film 3, and a substrate 4.

That is, in the first embodiment, the light emitting element 100 according to the present invention has the resin portion formed on the outer peripheral portion of the LED element 1. And the said fluorescent substance containing resin layer (resin part) 2 contains the fluorescent substance which absorbs a part of light emission from the said LED element 1, changes wavelength, and light-emits. The “outer peripheral part” means that the LED element 1 is outside in the light emission direction as viewed from the LED element 1.

The LED element 1 is mounted on the mounting surface 6 of the substrate 5 with a silicone-based resin paste or the like. The substrate 5 is preferably made of a material having a high reflective effect on the mounting surface, and for example, a ceramic substrate is preferably used.

On the substrate 5, a front surface electrode (not shown) for wire bonding is mounted on the mounting surface 6, and a back surface electrode (not shown) for connecting to an external circuit on the back surface (the surface on which the LED element 1 is not mounted). ), And a through hole (not shown) for conducting the front surface electrode and the back surface electrode is provided inside.

The LED element 1 may be any element that can emit blue light (wavelength of 435 nm or more and 480 nm or less). For example, a nitride-based compound semiconductor such as InGaN can be used.

The LED element 1 is mounted (die bonding) on the mounting surface 6 of the substrate 5 and is electrically connected to the surface electrode of the substrate 5 by a wire (not shown) made of, for example, gold. As a result, power is supplied to the LED element 1 from the back electrode of the substrate 5.

The number of the LED elements 1 may be one or plural. When the number of the LED elements 1 is plural, the LED elements 1 may be disposed at a predetermined position that satisfies a predetermined light emission amount, for example, at equal intervals.

The phosphor-containing resin layer (resin portion) 2 is formed so as to cover the LED element 1 and seals the LED element 1. The phosphor-containing resin layer (resin portion) 2 is made of a resin containing a phosphor. The resin is preferably a silicone resin because of its excellent translucency, and an epoxy resin, an acrylic resin, or the like can also be used. Silicone resins are particularly preferable because they are excellent in heat resistance.

The phosphor absorbs part of the light emitted from the LED element 1 (blue light), converts the wavelength, and emits yellow light. Examples of such phosphors include CaAlSiN ₃ : Eu, (Si · Al) ₆ (O · N) ₈ : Eu, BOSE (Ba, O, Sr, Si, Eu), SOSE (Sr, Ba, Si, O, Eu), YAG (Ce activated yttrium aluminum garnet), α sialon ((Ca), Si, Al, O, N, Eu), β sialon (Si, Al, O, N, Eu), etc. It can be used suitably.

(Regarding adjustment of chromaticity by reflecting film)
The phosphor-containing resin layer (resin portion) 2 in the present invention includes a reflective film 3 on the surface. The reflection film 3 is formed on the surface of the phosphor-containing resin layer (resin portion) 2 so that the transmission characteristics of the emitted light emitted from the reflection film 3 to the outside (in this specification, “light transmission” It is also referred to as “characteristic”.). “Transmission characteristics of emitted light” refers to the characteristics of the reflective film 3 such as what wavelength the reflective film 3 easily emits to the outside and what wavelength light easily reflects. “To produce wavelength dependency in the transmission characteristics of outgoing light” means that the reflectance of light having a wavelength in a specific range is stronger than the reflectance of light having a wavelength in other ranges. The “outside” refers to the outside of the light emitting element 1. That is, it refers to a region outside the reflective film 3 in the light emission direction.

Since the reflective film 3 has a refractive index larger than that of the phosphor-containing resin layer (resin portion) 2, the reflectance of short wavelength light (for example, blue light) can be reduced with a relatively thin film thickness. The difference between the reflectance of long-wavelength light (for example, yellow light) can be increased, that is, the thickness can be increased to several percent while the film thickness accuracy is improved. . In the present specification, the refractive index of the reflective film 3 is also referred to as “refractive index n ′”, and the refractive index of the phosphor-containing resin layer (resin portion) 2 is also referred to as “refractive index n”.

The wavelength dependence of the light transmission characteristics of the reflective film 3 is an interference involving the refractive index of the reflective film 3, the refractive index of the phosphor-containing resin layer (resin portion) 2, and the film thickness of the reflective film 3. Therefore, by adjusting the film thickness of the reflective film 3, the wavelength dependence of the light transmission characteristics can be controlled, and white light having a desired chromaticity characteristic can be obtained.

For example, in Example 1 described later, TiO ₂ having a refractive index n ′ of 2.5 and a silicone resin having a refractive index n of the resin portion of 1.41 are used. At this time, when the thickness of the reflective film 3 is 10 nm and 15 nm, the result shows that the reflectance is higher as the light has a shorter wavelength and the reflectance is lower as the light has a longer wavelength. That is, for example, the reflectance of blue light is higher than the reflectance of yellow light.

Therefore, when the reflecting film 3 is not formed, the blue light emitted from the LED element 1 and a part of the light emitted from the LED element 1 are absorbed, and the yellow from the phosphor emitted by wavelength conversion is absorbed. When the light mixed with the light is more blue than the desired chromaticity as white light, the refractive index of the reflective film 3 is set to be the same as that of the phosphor-containing resin layer (resin portion) 2 as in Example 1. The reflective film 3 having a refractive index larger than that of the reflective film 3 and having a thickness of 10 nm or 15 nm, for example, may be formed on the surface of the phosphor-containing resin layer (resin portion) 2.

As a result, the blue light transmitted through the reflective film 3 and emitted from the light emitting element 100 is reduced, and the blue light is wavelength-converted by the phosphor existing in the phosphor-containing resin layer 2. As a result, since the ratio of yellow light in the emitted light increases, the light emitted from the light emitting element 100 has chromaticity shifted to the yellow side as compared with the case where the reflective film 3 is not provided.

Therefore, since the chromaticity of the emitted light in which the emitted light is blue lighter than the prescribed chromaticity as white light can be optimized and the emission of the blue light can be suppressed, the quality of the light emitting element 100 can be improved. The blue light retinopathy can be reduced.

On the other hand, in Example 1 described later, when the thickness of the reflective film 3 is 80 nm, the reflectance of blue light is significantly lower than the reflectance of yellow light. In this way, by designing the reflective film 3 so that the reflectance of light having a long wavelength is high, for example, a reflective film in which the reflectance of green light to red light is higher than that of blue light is formed. Yes.

Thereby, the chromaticity of the light emitted from the light emitting element 100 to the outside can be adjusted from the yellow side to the blue side (direction in which the chromaticity decreases). The adjustment of chromaticity in this case is realized not by the wavelength conversion efficiency by the phosphor but by the loss of the long wavelength component.

Therefore, when the above mixed light is more yellow than the desired chromaticity as white light, the refractive index of the reflective film 3 is changed to the phosphor-containing resin layer (resin portion) 2 as in Example 1. The reflective film 3 may be formed on the surface of the phosphor-containing resin layer (resin portion) 2, for example, with a refractive index greater than the refractive index of the phosphor-containing resin layer (resin portion) 2.

Thereby, yellow light transmitted through the reflective film 3 and emitted from the light emitting element 100 is reduced. As a result, since the proportion of blue light in the emitted light increases, the light emitted from the light emitting element 100 has a chromaticity shifted to the blue side as compared with the case where the reflective film 3 is not provided.

Here, Patent Document 4 discloses an LED light source in which the refractive index of the transparent thin film is smaller than the refractive index of the transparent resin in the sealing material. Patent Document 4 discloses that the wavelength dependence of light transmission characteristics is confirmed, that is, the reflectance depends on the wavelength, but the film thickness disclosed in Patent Document 4 is about 300 nm. It is a thick film. For this reason, the technique disclosed in Patent Document 4 has a problem that the accuracy of film thickness control by film formation deteriorates.

In Patent Document 4, since the difference in reflectance with respect to the confirmed wavelength is about 1%, there is a problem that the range of chromaticity that can be adjusted is small. Furthermore, since the refractive index of the resin is generally 1.4 to 1.8, and a substance having a refractive index smaller than this refractive index is very rare, the combination of the transparent thin film and the transparent resin However, there is no practical combination. Therefore, it is difficult to give wavelength dependency to the transmission characteristics of light passing through the transparent thin film.

On the other hand, as described above, since the refractive index of the reflective film 3 is larger than the refractive index of the phosphor-containing resin layer (resin portion) 2, for example, even if the film thickness is several tens of nanometers, short wavelength light The difference between the reflectance of (for example, blue light) and the reflectance of long-wavelength light (for example, yellow light) can be made significantly larger than about 1%.

However, the film thickness of the reflective film 3 is not limited to the film thickness used in the above embodiment. As described above, since the refractive index of the reflective film 3 is larger than the refractive index of the phosphor-containing resin layer (resin portion) 2 in the present invention, the film thickness can be made relatively thin. That is, it is not a thick film of about 300 nm like the film disclosed in Patent Document 4, but can be a relatively thin film. The thickness of the reflective film 3 is not particularly limited, but is preferably 10 nm or more. Moreover, as an upper limit, it is preferable that it is 80 nm or less.

In the reflective film 3 of the present invention, the reflectance of visible light having a wavelength of 435 nm or more and 480 nm or less is higher than the reflectance of visible light having a wavelength of 500 nm or more and 700 nm or less, more specifically, blue light (wavelength 435 nm or more and 480 nm or less) reflectivity of green light (wavelength of 500 nm or more and 560 nm or less), yellow green light (wavelength of 560 nm or more and 580 nm or less), yellow light (wavelength of 580 nm or more and 595 nm or less), orange light (wavelength of 595 nm or more and 605 nm or less) and The configuration may be higher than the reflectance of red light (wavelength 605 nm or more and 700 nm or less).

Further, the reflective film 3 may have a configuration in which the reflectance of visible light having a wavelength of 500 nm to 700 nm is higher than the reflectance of visible light having a wavelength of 435 nm to 480 nm.

The wavelength dependence of such light transmission characteristics of the reflective film 3, that is, the wavelength dependence of the reflectance can be adjusted by appropriately controlling the film thickness of the reflective film 3 in consideration of the influence of the interference described above. it can. The relationship between the thickness of the reflective film 3, the wavelength of light incident on the reflective film 3, and the reflectance of the light of the reflective film 3 can be determined by a conventionally known matrix method.

As described above, the refractive index of the reflective film 3 is larger than the refractive index of the phosphor-containing resin layer (resin portion) 2. At this time, the difference between the refractive index of the reflective film 3 and the refractive index of the phosphor-containing resin layer (resin portion) 2 is preferably 1 or more.

If the difference between the refractive index of the reflective film 3 and the refractive index of the phosphor-containing resin layer (resin part) 2 is about 1 as shown in the examples described later, the reflective film 3 that is a single layer film is used. By using the wavelength dependence of the reflective film 3, the chromaticity of the emitted light can be optimized.

On the other hand, in the LED light source disclosed in Patent Document 4, the refractive index of the transparent thin film is smaller than the refractive index of the transparent resin in the sealing material. In this case, although light emission from the sealing resin to the air is good, as described above, it is difficult to give wavelength dependency to the transmission characteristics of light passing through the transparent thin film.

FIG. 2 is a chromaticity diagram for explaining variation in chromaticity depending on the presence or absence of the reflective film 3 in the light emitting element 100 shown in FIG. Here, a plurality of LED elements 1 are provided inside the phosphor-containing resin layer (resin portion) 2 for the light-emitting element 100 that includes the phosphor-containing resin layer (resin portion) 2 and is not formed with the reflective film 3. Assume that the result of measuring the chromaticity of the emitted light of all the LED elements 1 when sealed is shown in FIG. The chromaticity can be measured by a conventionally known method using a commonly used chromaticity meter.

As shown in FIG. 2A, the light before the formation of the reflective film 3 varies in chromaticity due to variations in the dispersion state of the phosphors dispersed in the phosphor-containing resin layer (resin part) 2. Is widespread.

Here, for example, when it is desired to increase the chromaticity of the emitted light of the light emitting element 100 in both the x direction and the y direction, it is necessary to change the chromaticity in the yellow direction, so that the phosphor-containing resin layer (resin portion) 2 By forming the reflective film 3 having a controlled film thickness on the surface, blue light is reflected more strongly than green light to red light. In the present specification, the surface of the phosphor-containing resin layer (resin portion) 2 refers to an outer surface in the light emitting direction among the surfaces of the phosphor-containing resin layer (resin portion) 2.

The reflected blue light returns to the phosphor-containing resin layer (resin portion) 2, undergoes wavelength conversion by the phosphor, and is emitted toward the reflection film 3. If the emitted light is yellow light, the light passes through the reflective film 3 and is emitted to the outside of the light emitting element 100.

On the other hand, when the light that has been subjected to the wavelength conversion and is emitted toward the reflective film 3 is still shifted to blue, the blue light contained in the light is reflected by the reflective film 3 and again the phosphor. Undergoes wavelength conversion. By repeating the above operation by increasing the number of wavelength conversions, it is possible to finally obtain light of the desired chromaticity without causing light loss even with a small amount of phosphor.

As described above, since the chromaticity is adjusted by forming the reflective film 3, the variation in chromaticity corresponding to the region shown in FIG. 2A is canceled out, and (b) of FIG. ), The chromaticity of light emitted from the light emitting element 100 to the outside can be adjusted from the blue side to the yellow side (direction in which the chromaticity increases).

Furthermore, since the number of wavelength conversions can be increased by the reflective film 3, the amount of the phosphor present in the phosphor-containing resin layer (resin portion) 2 can be reduced, and the cost can be reduced. Play.

The reflective film 3 contains an inorganic oxide. The inorganic oxide is preferably, for example, titanium oxide or zinc oxide. Titanium oxide or zinc oxide is an inexpensive material having a refractive index one or more larger than that of a silicone resin preferable as a resin contained in the phosphor-containing resin layer (resin portion) 2, and is formed by a simple process. This is preferable because it is possible. The titanium oxide is not particularly limited, but is preferably one or more compounds selected from the group consisting of TiO ₂ , TiO, and Ti ₃ O ₅ .

The effect that the weather resistance of the light emitting element 100 can be improved by the reflective film 3 containing an inorganic oxide is also exhibited.

In particular, for example, when titanium oxide or zinc oxide is used as the inorganic oxide, and a silicone resin is used as the resin contained in the phosphor-containing resin layer (resin portion) 2, relatively strong —Ti—O—Si— And the like, the adhesion between the silicone resin and the inorganic oxide is increased, and the adhesion between the reflective film 3 and the phosphor-containing resin layer (resin portion) 2 can be improved. Play.

Thereby, it is possible to provide the light emitting device 100 having good adhesion between the reflective film 3 and the phosphor-containing resin layer (resin portion) 2 and excellent weather resistance.

When the reflective film 3 contains an inorganic oxide, the reflective film 3 can be a dielectric film having a photocatalytic action. Thus, the light emitting device 100 according to the present invention can exhibit effects such as an antifouling effect, an antifogging effect, an antibacterial effect, an air purification effect, and a water purification effect.

The light emitting device 100 according to the present invention exhibits antifouling and antifogging effects, so that the intensity and brightness of light emitted from the light emitting device 100 can be kept constant, and the light emitting device 100 can be used. The period can be lengthened.

In addition, the light emitting device 100 according to the present invention has an antibacterial effect, an air purification effect, and a water purification effect, and thus has a more useful effect on the effect of stably emitting white light having a desired chromaticity. Will be added. Therefore, the commercial value of the light emitting device 100 according to the present invention can be further improved.

The preferred content of the inorganic oxide in the reflective film 3 varies depending on the physical properties of the inorganic oxide contained in the reflective film 3, the amount of wavelength component to be adjusted, the wavelength of light incident on the reflective film 3, and the like. I can't say that. The reflective film 3 may be made of the above inorganic oxide.

The reflective film 3 in the present invention is preferably produced using a vapor deposition method. By using the vapor deposition method, it is easy to precisely adjust the thickness of the reflective film 3. In addition, even if the shape of the phosphor-containing resin layer (resin portion) 2 is uneven, the film can be easily formed.

That is, by using the vapor deposition method, a reflective film having a desired film thickness can be formed with high accuracy by a simple film formation method, and the chromaticity can be adjusted according to the film thickness. it can. The vapor deposition method is also referred to as vapor deposition, and refers to a technique for growing a thin film on the surface of a material by making the material in a gas (vapor phase) state.

The vapor deposition method is not particularly limited, and any of physical vapor deposition (Physical Vapor Deposition; PVD) and chemical vapor deposition (Chemical Vapor Deposition; CVD) can be used.

Physical vapor deposition is not particularly limited, and sputtering, vacuum vapor deposition, molecular beam epitaxy, ion plating, laser deposition, and the like can be used. Among these, sputtering can be particularly preferably used because simple and highly accurate film formation can be performed.

The chemical vapor deposition is not particularly limited, and thermal CVD method, photo CVD method, plasma CVD method, atmospheric pressure CVD (AP-CVD), low pressure CVD (LP-CVD), metal organic chemical vapor deposition method, etc. Can be used. Chemical vapor deposition can be preferably used because it has a high film forming speed, can increase the treatment area, and can evenly form a film even on an uneven surface.

(About phosphor concentration)
The density | concentration of the fluorescent substance in the said fluorescent substance containing resin layer (resin part) 2 is not specifically limited, For example, the density | concentration in the vicinity area | region of the said LED element 1 is a vicinity area | region of the said reflecting film 3 It may be higher than the concentration in.

In the first embodiment of the present specification and the second embodiment to be described later, “the vicinity region of the LED element 1” refers to the inner surface of the reflective film 3 from any point on the outer surface of the LED element 1 ( When a straight line is drawn to the surface of the reflective film 3 up to the surface containing the phosphor-containing resin layer (resin portion 2), any one of the outer surfaces of the LED element 1 is on the straight line. The distance to the point is a region formed by a point shorter than the distance to the inner surface of the reflective film 3.

The “region in the vicinity of the reflective film 3” is a line drawn from any point on the inner surface of the reflective film 3 to any point on the outer surface of the LED element 1. In addition, the distance to any point on the inner surface of the reflective film 3 is a region formed by a point shorter than the distance to any point on the outer surface of the LED element 1. The “outer surface” refers to an outer surface in the light emission direction as viewed from the LED element 1.

In FIG. 1, a part of the light a emitted from the LED element 1 is reflected by the reflective film 3 and separated into emitted light c and reflected light b. The reflected light b reflected is scattered by the phosphor present in the phosphor-containing resin layer (resin portion) 2 (wavelength conversion is also performed).

The wavelength-converted light d is immediately emitted to the outside of the light emitting element 100, or part of the light is reflected by the reflective film 3 and undergoes further wavelength conversion by the phosphor. Then, the outgoing light c having the wavelength λ and the light d having the wavelength λ ′ are mixed, and white light having a desired chromaticity can be obtained.

<Second Embodiment>
(Light Emitting Element According to Another Form of the Present Invention)
In the first embodiment, as shown in FIG. 1, in the light emitting element 100, the phosphor-containing resin layer (resin portion) 2 and the reflective film 3 are formed in a hemispherical shape on the mounting surface 5 of the substrate 4. . However, the form of the light emitting element is not limited to this. In the second embodiment, a light-emitting element that takes a form different from that of the first embodiment will be described.

FIG. 3 is a schematic cross-sectional structure diagram of a light emitting device 101 according to the second embodiment of the present invention. In the light emitting element 101, the reflection frame 6 is disposed on the mounting surface 5 of the substrate 4.

The reflection frame 6 is used for efficiently irradiating the reflection film 3 with light emitted from the LED element 1 or the phosphor, and one having a high surface reflectance such as resin, ceramic, or metal material is used. For example, the light beam emitted from the LED element 1 in the lateral direction can be emitted in the direction of the reflective film 3 by being reflected by the reflection frame 6. The reflection frame 6 may be formed on the mounting surface 5 as a separate body from the substrate 4 or may be integrally formed with the substrate 4.

In the light emitting element 101, a phosphor-containing resin layer (resin part) 2 is formed on the outer periphery of the LED element 1. A reflective film 3 is formed across the surface of the phosphor-containing resin layer (resin portion) 2 and the reflective frame 6. The reflective film 3 is formed on the surface of the phosphor-containing resin layer (resin portion) 2, thereby causing wavelength dependence in the transmission characteristics of the emitted light emitted from the reflective film 3 to the outside.

As shown in FIG. 3, a part of the light a emitted from the LED element 1 is reflected by the reflective film 3 and separated into reflected light b and emitted light c. The reflected light b is wavelength-converted by the phosphor existing in the phosphor-containing resin layer (resin portion) 2 and is emitted from the light emitting element 101 as the emitted light d. The light a is partly wavelength-converted by a phosphor after being emitted, and is emitted from the light emitting element 101 as emitted light d ′.

The light-emitting element 101 is different from the light-emitting element 100 according to the first embodiment in the shapes of the phosphor-containing resin layer (resin portion) 2 and the reflective film 3, but the reflective film 3 depends on the wavelength of light transmission characteristics as described above. Therefore, according to the chromaticity characteristics when there is no reflective film 3, by selecting the reflective film 3 that produces an appropriate wavelength dependence, the light mixed with the outgoing light c, d, d ' White light having desired chromaticity characteristics can be obtained.

The density | concentration of the fluorescent substance in the said fluorescent substance containing resin layer (resin part) 2 is not specifically limited, For example, the density | concentration in the vicinity area | region of the said LED element 1 is a vicinity area | region of the said reflecting film 3 It may be higher than the concentration in.

<Third Embodiment>
(Method for Manufacturing Light-Emitting Element According to the Present Invention)
A method for manufacturing a light emitting device according to the present invention includes: a resin portion containing a phosphor that absorbs a part of light emitted from an LED device and converts the wavelength to emit light; A first step of sealing and sealing the LED element; a second step of measuring chromaticity characteristics of light emitted from the LED element through the resin portion; and the measured color According to the degree characteristics, the surface of the resin part is formed with a reflection film that contains an inorganic oxide, has a refractive index larger than the refractive index of the resin part, and has a wavelength dependency in light transmission characteristics. 3 steps.

The light emitting device 100 according to the first embodiment and the light emitting device 101 according to the second embodiment described above can be manufactured by the method.

FIG. 4 is a schematic diagram showing a schematic diagram of the steps of the method for producing a light emitting device according to the present invention. 4A shows a method for manufacturing the light emitting device 100 according to the first embodiment, and FIG. 4B shows a method for manufacturing the light emitting device manufacturing method 101 according to the second embodiment. .

First, as shown in FIGS. 4 (a), (1), (b) and (1), the LED element 1 is mounted on the mounting surface 5 of the substrate 4, and (a), (2) and (b) in FIG. Wire bonding is performed using the wire 7 and a conventionally known wire bonding machine 8 as shown in (2).

Subsequently, as shown in FIGS. 4A and 3, the phosphor-containing resin layer (resin portion) 2 is placed on the mounting surface 5 so as to cover the LED element 1 using a dispenser (not shown). The LED element 1 is sealed, and the phosphor-containing resin layer (resin portion) 2 is covered and molded by the mold 9.

4 (b) and (3), the phosphor-containing resin layer (resin portion) 2 is applied to the recess formed by the mounting surface 5 and the reflection frame 6 using the dispenser 10 so as to cover the LED element 1. It inject | pours, the LED element 1 is sealed and the fluorescent substance containing resin layer (resin part) 2 is formed.

Next, the chromaticity characteristics of light emitted from the LED element 1 through the phosphor-containing resin layer (resin portion) 2 are measured. Then, based on the measurement result, select the reflective film 3 that produces the wavelength dependency necessary to obtain the desired measurement result, the reflective film 3 on the surface of the phosphor-containing resin layer (resin part) 2, It forms and forms using a vapor-phase film-forming method (for example, sputtering, CVD).

Finally, as indicated by arrows in FIGS. 4A, 4B, and 4B, the phosphor-containing resin layer 2 is cured by irradiating with UV or the like, so that the light emitting element 100 or the light emitting element is obtained. 101 can be manufactured.

In addition to the above-described steps shown in FIG. 4, the light emitting element having a higher concentration in the vicinity of the LED element 1 than the concentration in the vicinity of the reflective film 3 is formed by the phosphor-containing resin layer (resin portion) 2. After the element 1 is sealed, it can be manufactured by adding a step of precipitating the phosphor contained in the phosphor-containing resin layer (resin portion) 2.

A reflective film made of TiO ₂ having a refractive index n ′ of 2.5 as a reflective film in the light emitting element, a silicone resin having a refractive index n of the phosphor-containing resin layer (resin part) of 1.41, For light-emitting elements having film thicknesses of 10 nm, 15 nm, and 80 nm, calculation was performed by a matrix method in which the incident angle of light was zero and the refractive index and phase film thickness were taken into consideration. In this calculation, the wavelength dependence of the refractive index (the chromatic dispersion of the material) and light absorption by the medium are not taken into consideration.

Fig. 5 shows the calculation results. In FIG. 5, “dielectric film” refers to a reflective film, and “resin” refers to a phosphor-containing resin layer (resin portion). The horizontal axis represents the wavelength of light, and the vertical axis represents the reflectance of the reflective film.

As can be seen from FIG. 5, the light-emitting element having a reflective film with a film thickness of 10 nm and 15 nm has a wavelength dependency such that the shorter wavelength light has higher reflectance and the longer wavelength light has lower reflectance. .

On the other hand, when the thickness of the reflective film is 80 nm, the reflectance with respect to light having a wavelength of 450 nm shows a minimum value, and thereafter, the reflectance increases as the wavelength increases.

This result shows that the reflective film containing the inorganic oxide has a refractive index larger than that of the phosphor-containing resin layer (resin portion), and then the reflective film is adjusted to adjust the reflection film thickness. It shows that the wavelength dependence of the rate can be controlled.

Therefore, by utilizing the wavelength dependency, light emission capable of emitting white light having a desired chromaticity by adjusting the refractive index and film thickness of the reflective film according to the light to be suppressed from being emitted from the light emitting element. An element can be realized.

[Comparative Example 1]
The light-emitting element in which the refractive index n ′ of the reflective film in the light-emitting element is 1.2, the refractive index n of the phosphor-containing resin layer (resin part) is 1.41, and the film thickness of the reflective film is 20 nm, 50 nm, and 100 nm. In the same manner as in Example 1, the calculation was performed by a matrix method in which the incident angle of light was set to zero and the refractive index and the phase film thickness were taken into consideration. In this calculation, the wavelength dependence of the refractive index (the chromatic dispersion of the material) and light absorption by the medium are not taken into consideration. FIG. 6 shows the calculation results.

As can be seen from FIG. 6, the light emitting element in which the refractive index n ′ of the reflective film is smaller than the refractive index n of the resin portion did not show the wavelength dependency of the reflectance.

[Summary]
The light-emitting elements 100 and 101 according to the first aspect of the present invention include the LED element 1 and a phosphor that absorbs part of the light emitted from the LED element 1 and converts the wavelength to emit light, and seals the LED element. A resin part (phosphor-containing resin layer 2) to be stopped, and a reflective film 3 containing an inorganic oxide and formed on the surface of the resin part, and the reflective film 3 is the resin part 2 Is formed on the surface of the reflective film 3, the wavelength dependence of the transmission characteristics of the outgoing light emitted from the reflective film 3 to the outside occurs, and the refractive index of the reflective film 3 is the resin part (phosphor-containing resin). Greater than the refractive index of layer 2).

According to the above configuration, since the refractive index of the reflective film 3 is larger than the refractive index of the resin portion (phosphor-containing resin layer 2), the thickness of the reflective film 3 is made relatively thin, and in the visible light region. The difference between the reflectance of short wavelength light (for example, blue light) and the reflectance of long wavelength light (for example, yellow light) can be increased.

Furthermore, by adjusting the film thickness of the reflective film 3, the wavelength dependence of the transmission characteristic of the emitted light can be controlled, and white light having a desired chromaticity characteristic can be obtained.

Therefore, it is possible to realize the light emitting elements 100 and 101 with small variations in chromaticity. Moreover, according to the said structure, since the frequency | count of wavelength conversion by a fluorescent substance can be increased, the fluorescent substance amount which exists in a resin part (phosphor containing resin layer 2) can be reduced, and material cost is reduced. There is an effect that can be. Furthermore, by suppressing the emission of blue light, there is an effect that blue light retinal damage can be reduced. In addition, since the reflection film 3 contains an inorganic oxide, the weather resistance of the light emitting elements 100 and 101 can be improved.

In the light-emitting elements 100 and 101 according to the second aspect of the present invention, the reflective film 3 in the first aspect is preferably a single-layer film manufactured using a vapor deposition method.

According to the above configuration, the reflective film 3 having a desired film thickness can be formed with high accuracy by an easy film forming method, and the chromaticity can be adjusted according to the film thickness. Moreover, according to the said structure, the light emitting elements 100 and 101 can be obtained efficiently and at low cost.

Therefore, it is possible to efficiently provide the light emitting elements 100 and 101 having the reflective film 3 formed with high accuracy.

In the light-emitting elements 100 and 101 according to the third aspect of the present invention, in the first or second aspect, the vapor deposition method is preferably sputtering or chemical vapor deposition.

According to the above configuration, the film thickness can be controlled with high accuracy regardless of the unevenness of the resin portion.

Therefore, it is possible to efficiently provide the light-emitting elements 100 and 101 having the reflective film 3 formed with higher accuracy.

In the light-emitting elements 100 and 101 according to the fourth aspect of the present invention, in the third aspect, the inorganic oxide is preferably a titanium oxide or zinc oxide, and the resin contained in the resin portion is preferably a silicone resin. .

According to the said structure, the refractive index of the reflecting film 3 can be made 1 or more larger than the refractive index of the resin part (phosphor containing resin layer 2), and it is manufactured by a simple process using an inexpensive material. Can be membrane.

Further, according to the above configuration, since a relatively strong bond such as —Ti—O—Si— is formed, the adhesion between the reflective film 3 and the resin portion (phosphor-containing resin layer 2) can be improved. .

Furthermore, according to the above configuration, since the reflective film 3 has a photocatalytic action, it exhibits an antifouling effect, an antifogging effect, an antibacterial effect, an air purification effect, a water purification effect, and the like.

Therefore, according to the above configuration, it is possible to provide the light emitting element 100 that can emit white light having desired chromaticity characteristics, has excellent reflection film adhesion, and exhibits various useful effects. There is an effect.

In the light-emitting elements 100 and 101 according to the fifth aspect of the present invention, in the fourth aspect, the titanium oxide is preferably one or more compounds selected from the group consisting of TiO ₂ , TiO, and Ti ₃ O _5. .

According to the above configuration, when a silicone resin is used as the resin contained in the resin portion (phosphor-containing resin layer 2), a relatively strong —Ti—O—Si— bond is formed. And the resin part (phosphor-containing resin layer 2) can be improved, and the reflective film 3 is not easily peeled off.

In the light-emitting elements 100 and 101 according to the sixth aspect of the present invention, the difference between the refractive index of the reflective film 3 and the refractive index of the resin portion (phosphor-containing resin layer 2) is preferably 1 or more.

According to the above configuration, as shown in the above-described embodiment, the chromaticity adjustment of the emitted light is performed using the reflective film 3 that is a single layer film, based on the fact that the reflective film 3 causes the wavelength dependence of the transmission characteristics of the emitted light. There is an effect that can be easily performed.

In the light-emitting elements 100 and 101 according to the aspect 7 of the present invention, the reflective film 3 preferably has a thickness of 10 nm to 80 nm.

According to the above configuration, the difference between the reflectance of short-wavelength light and the reflectance of long-wavelength light can be increased in a visible light range with a relatively thin film thickness.

Therefore, it is possible to improve the film thickness accuracy and increase the width of the adjustable chromaticity.

The manufacturing method of the light emitting elements 100 and 101 according to the aspect 8 of the present invention includes a resin part (phosphor-containing resin) containing a phosphor that absorbs part of the light emitted from the LED element 1 and converts the wavelength to emit light. The layer 2) is formed so as to cover the LED element 1 mounted on the mounting surface 5 of the substrate 4, and the LED element 1 is sealed. On the surface of the resin part (phosphor-containing resin layer 2) according to the second step of measuring the chromaticity characteristics of light emitted through the body-containing resin layer 2) and the measured chromaticity characteristics. In addition, it contains an inorganic oxide, has a refractive index greater than the refractive index of the resin part, and is formed on the surface of the resin part. A third step of forming the reflective film 3 to generate

According to the above configuration, a reflective film having a desired film thickness can be formed by a simple process according to the measured chromaticity characteristics. Thereby, since the reflective film 3 that causes the wavelength dependency of the light transmission characteristics is formed, variation in chromaticity of light emitted from the light emitting elements 100 and 101 can be effectively suppressed, and desired chromaticity characteristics can be suppressed. The light-emitting elements 100 and 101 capable of emitting white light having the above can be manufactured. Moreover, according to the said structure, the light emitting elements 100 and 101 with improved quality can be manufactured.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

The present invention can be suitably used in the field related to a light emitting element combined with a phosphor. Further, it can be widely used in the fields of various electric devices such as a mobile phone including a light emitting element.

1 LED element 2 Phosphor-containing resin layer (resin part)
DESCRIPTION OF SYMBOLS 3 Reflective film 4 Board | substrate 5 Mounting surface 6 Reflective frame 7 Wire 100, 101 Light emitting element

Claims (6)

1. An LED element;
   A resin part that absorbs part of the light emitted from the LED element, contains a phosphor that emits light after wavelength conversion, and seals the LED element;
   A reflection film containing an inorganic oxide and formed on the surface of the resin part,
   The reflection film is formed on the surface of the resin portion, thereby causing wavelength dependency in the transmission characteristics of the emitted light emitted from the reflection film to the outside.
   The light emitting element characterized by the refractive index of the said reflecting film being larger than the refractive index of the said resin part.
2. 2. The light-emitting element according to claim 1, wherein the reflective film is a single-layer film produced using a vapor deposition method.
3. The light emitting device according to claim 2, wherein the vapor deposition method is sputtering or chemical vapor deposition.
4. The light-emitting element according to any one of claims 1 to 3, wherein the inorganic oxide is titanium oxide or zinc oxide, and the resin contained in the resin portion is a silicone resin.
5. _5. The light emitting device according to claim 4, wherein the titanium oxide is one or more compounds selected from the group consisting of TiO ₂ , TiO, and Ti ₃ O ₅ .
6. The light emitting device according to any one of claims 1 to 5, wherein a difference between a refractive index of the reflective film and a refractive index of the resin portion is 1 or more.

Images