JP2011107508A - Phosphor filter, method of manufacturing the same, and lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phosphor filter for efficiently taking out light emitted by a light emitting element as uniform light having no color irregularity regardless of the viewing angle. <P>SOLUTION: The phosphor filter 10 for a semiconductor light emitting element integrally includes a first dichroic filter 1 for transmitting first visible light and reflecting second visible light of a wavelength longer than that of the first visible light, a phosphor layer 2 that is stacked on the first dichroic filter 1 and contains a phosphor for wavelength-converting the first visible light into the second visible light, a second dichroic filter 3 that is stacked on the opposite side to the first dichroic filter 1 of the phosphor layer 2, reflects the first visible light propagating in the thickness direction, and transmits the second visible light, and a light scattering layer 4 that is stacked on the opposite side to the phosphor layer 2 of the second dichroic filter 3 and scatters the emission light emitted from the second dichroic filter 3 while transmitting it. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a phosphor filter, a method for manufacturing the phosphor filter, and a lamp, and is arranged on the light emitting side of the light emitting element, and the light emitted from the light emitting element is efficiently converted into light that is uniform and has no color unevenness regardless of the viewing angle. The present invention relates to a phosphor filter that can be taken out well, a manufacturing method thereof, and a lamp including the phosphor filter.

Some lamps including a light emitting element such as a light emitting diode (LED) element convert the wavelength of light emitted from the light emitting element and emit light having a wavelength different from that of the light emitted from the light emitting element.
Specifically, a light emitting element such as a light emitting diode that emits blue light is provided, and a part of the blue light emitted from the light emitting element is wavelength-converted by the phosphor, and the light emitted from the phosphor and blue that has not been wavelength-converted There are lamps that emit white light by color mixing with light. However, in such a lamp, as described below, it is difficult to efficiently extract the light emitted from the light emitting element as white light having no color.

That is, since the phosphor converts the wavelength of blue light, if the amount of the phosphor is small, the proportion of blue light emitted without wavelength conversion increases, and the light emitted from the lamp is blue. It becomes light. However, increasing the amount of phosphor increases the amount of light that is converted by the phosphor and refracted and reflected repeatedly by other phosphors and cannot be taken out of the lamp. It will not be possible to take out well.
In addition, since the light whose wavelength has been converted by the phosphor is emitted from the phosphor in all directions, it is also emitted in a direction in which the light cannot be directly extracted. Such light travels toward the inside of the LED lamp, such as the lead frame, the case resin of the package, and the LED element, where only the light reflected toward the outside of the lamp is emitted, and thus the emitted light is attenuated.

In order to solve this problem, a dichroic filter that transmits blue light and reflects the converted light converted by the phosphor and a dichroic filter on the side opposite to the light emitting element are provided. There is a technique for emitting blue light emitted from a light emitting element as white light through a phosphor layer for wavelength conversion.
For example, Patent Document 1 discloses that an LED element having an emission center wavelength of 470 nm, a phosphor layer of a glass sealing portion that emits converted light by irradiating the phosphor with light, and transmitting blue light. A semiconductor light emitting device is described that includes a dichroic filter that reflects light converted from a phosphor to prevent re-incidence of light emitted from a phosphor to a glass sealing portion.
Patent Documents 2 to 5 also propose a technique using a phosphor and a dichroic filter that transmits blue light and reflects converted light.

  From the light emitting element through a dichroic filter that transmits blue light and reflects converted light, and a phosphor layer that is provided on the opposite side of the light emitting element of the dichroic filter and converts the wavelength of blue light into converted light by the phosphor. When emitting the emitted blue light as white light, among the converted light obtained by being totally reflected by the phosphor, the converted light traveling from the phosphor layer to the light emitting element side is reflected by the dichroic filter, and the phosphor layer Can be returned to. Therefore, of the converted light obtained by being totally reflected by the phosphor, the converted light traveling from the phosphor layer to the light emitting element side can be eliminated, and the light emitted from the light emitting element can be efficiently extracted. Also, by returning the converted light traveling from the phosphor layer to the light emitting element side to the phosphor layer, the amount of converted light that can be extracted out of the lamp can be increased, so the amount of phosphor contained in the phosphor layer can be reduced. Can do. Therefore, it is possible to reduce the amount of light that the converted light converted by the phosphor is repeatedly refracted and reflected by other phosphors and cannot be taken out of the lamp, and the light emitted from the light emitting element can be efficiently extracted. it can.

Patent Document 6 describes a dielectric multilayer film that reflects only blue light and transmits light of other wavelengths as a blue light reflecting film constituting a cross dichroic prism.
Patent Document 7 describes a dielectric multilayer film that reflects blue light, for example, light having a wavelength of 525 nm, as a dichroic filter film constituting a cross dichroic prism.

Further, in FIG. 6 of Patent Document 1, a light emitting unit mounted on a case and a phosphor layer that covers an opening of the case and contains an RGB phosphor are laminated, which transmits visible light and transmits ultraviolet light. There is described an LED lamp having a dichroic filter that reflects, and a light emitting section having an ultraviolet LED element as a light source, and a dichroic filter that transmits ultraviolet light and reflects visible light.
Furthermore, Patent Document 1 describes a configuration in which an ultraviolet LED element is a blue LED element, an RGB phosphor is a yellow phosphor, and white light is emitted externally.

  In the technique described in FIG. 6 of Patent Document 1, a dichroic filter that transmits ultraviolet light as light source light and reflects visible light is disposed on the light source side with respect to a phosphor layer containing RGB phosphors. A dichroic filter that reflects ultraviolet light and transmits visible light is arranged on the light emission side of the layer, so that visible light traveling from the phosphor layer to the light source side can be returned to the phosphor layer and taken out of the LED lamp. The amount of visible light can be increased, and ultraviolet light that has not been converted into RGB phosphors can be converted back to the phosphor layer and passed through the phosphor layer again, allowing efficient wavelength conversion. The amount of RGB phosphor contained can be reduced.

JP 2006-202962 A JP 2007-109947 A JP 2007-81234 A JP 2006-216753 A JP 2007-59864 A JP 2007-78779 A JP 2008-96766 A

  However, a dichroic filter that transmits blue light and reflects the converted light converted by the phosphor, and a phosphor layer that is provided on the side opposite to the light emitting element of the dichroic filter and converts the wavelength of the blue light into converted light by the phosphor. When the blue light emitted from the light emitting element is emitted as white light via the blue light, the blue light emitted from the light emitting element and not wavelength-converted to the phosphor is emitted as it is. For this reason, when the amount of the phosphor is small, the ratio of blue light emitted without wavelength conversion increases, and the light emitted from the lamp becomes a bluish color. For this reason, when the dichroic filter is provided, the amount of the phosphor can be reduced as compared with the case where the dichroic filter is not provided, but the amount of the phosphor that can be reduced is small. Therefore, it has been required to reduce the amount of the phosphor further and to extract the light emitted from the light emitting element more efficiently.

  In addition, a dichroic filter that transmits ultraviolet light, which is light source light, and reflects visible light is arranged on the light source side of the phosphor layer containing RGB phosphors, and ultraviolet light is emitted on the light emitting side of the phosphor layer. In the technique described in Patent Document 1 in which a dichroic filter that reflects and transmits visible light is disposed, it is difficult to obtain high-output light source light using an ultraviolet LED element. It was not obtained. In the technique described in Patent Document 1, since ultraviolet light having a short emission wavelength and high energy is used as the light source light, the material forming the LED lamp such as a sealing resin is easily deteriorated. There was a problem that the lifetime was short compared with the LED lamp which does not use ultraviolet light as light.

The present invention has been made in view of the above problems, and provides a phosphor filter that can efficiently extract light emitted from a light-emitting element as uniform, non-uniform color light regardless of the viewing angle, and a method for manufacturing the same. The task is to do.
Another object of the present invention is to provide a lamp that includes the phosphor filter of the present invention and can efficiently extract light emitted from a light-emitting element as uniform and non-uniform light regardless of the viewing angle. To do.

  In order to solve the above-mentioned problems, the present inventor has made extensive studies. As a result, a first dichroic filter that transmits the first visible light and reflects the second visible light having a longer wavelength than the first visible light, and a first dichroic filter are stacked, and the first visible light is A phosphor layer containing a phosphor for wavelength conversion into second visible light; and a layer on the opposite side of the phosphor layer from the first dichroic filter to reflect the first visible light traveling in the thickness direction and the second It has been found that the light emitted from the light emitting element can be efficiently extracted by emitting the light emitted from the light emitting element through the second dichroic filter that transmits visible light.

  In order to solve the above-mentioned problems, the present inventor has further studied earnestly. As a result, a light scattering layer is provided on the opposite side of the phosphor layer of the second dichroic filter, and light emitted from the light emitting element is passed through the first dichroic filter, the phosphor layer, the second dichroic filter, and the light scattering layer. The light scattering layer transmits the vertical light transmitted through the second dichroic filter in the thickness direction and the oblique light transmitted through the second dichroic filter traveling in the direction inclined with respect to the vertical light while being transmitted by the light scattering layer. It was found that by scattering and mixing, the light emitted from the light emitting element can be extracted more efficiently and color unevenness can be effectively prevented, and the present invention has been completed. That is, the present invention relates to the following.

(1) A first dichroic filter that transmits first visible light and reflects second visible light having a wavelength longer than that of the first visible light; and a first dichroic filter that is stacked on the first dichroic filter. A phosphor layer containing a phosphor that converts the wavelength to the second visible light; and a layer opposite to the first dichroic filter of the phosphor layer, and reflects the first visible light traveling in the thickness direction, and A second dichroic filter that transmits second visible light; and a light scattering layer that is stacked on the opposite side of the phosphor layer of the second dichroic filter and that scatters while transmitting the emitted light emitted from the second dichroic filter. A phosphor filter for a semiconductor light emitting device, characterized in that is integrated.

(2) One or both of the second dichroic filter and the first dichroic filter are alternately stacked with a plurality of low refractive index films and high refractive index films having a higher refractive index than the low refractive index film. The phosphor filter according to (1), which is made of a dielectric multilayer film.
(3) The phosphor filter according to (1) or (2), wherein the phosphor is unevenly distributed on one surface side of the phosphor layer.
(4) The first visible light has a peak wavelength in a range of 400 nm to 500 nm, and the second visible light has a peak wavelength in a range of 500 nm to 800 nm. The phosphor filter according to any one of (1) to (3).

(5) The phosphor filter according to any one of (1) to (4), wherein the light scattering layer is made of a resin film having a plurality of irregularities.
(6) The phosphor filter according to (5), wherein the plurality of irregularities are formed only on a surface of the light scattering layer opposite to the second dichroic filter.
(7) The light scattering layer is made of a resin film including a resin base material, and a plurality of particles having different refractive indexes from the resin base material integrated with the resin base material (1) The phosphor filter according to any one of to (4).
(8) The phosphor filter according to any one of (1) to (4), wherein the light scattering layer is made of a resin film containing a plurality of bubbles.

(9) The method for producing the phosphor filter according to any one of (1) to (8), wherein a step of providing the second dichroic filter on a light scattering layer made of a resin film, and the second dichroic A method for producing a phosphor filter, comprising: a step of providing a phosphor layer on a filter; and a step of providing the first dichroic filter on the phosphor layer.
(10) The phosphor filter according to (9), wherein one or both of the second dichroic filter and the first dichroic filter are formed by forming a film at a temperature of 200 ° C. or lower. Method.
(11) The step of providing the phosphor layer includes a step of applying and curing a coating solution made of a resin containing a phosphor on the second dichroic filter (9) or (10) ). The manufacturing method of the fluorescent substance filter of description.

(12) A substrate, a semiconductor light emitting device that emits light having a wavelength of 500 nm or less disposed on the substrate, and a phosphor filter that converts the wavelength of the emitted light of the semiconductor light emitting device, the phosphor filter comprising: The phosphor filter according to any one of (1) to (8), wherein the first dichroic filter is disposed toward the semiconductor light emitting element side.

  The phosphor filter of the present invention is laminated on the first dichroic filter, the first dichroic filter that transmits the first visible light and reflects the second visible light having a longer wavelength than the first visible light, A phosphor layer containing a phosphor that converts the wavelength of the first visible light into the second visible light, and the first visible light that is laminated on the opposite side of the phosphor layer from the first dichroic filter and proceeds in the thickness direction. A second dichroic filter that reflects and transmits the second visible light, and a second dichroic filter that is laminated on the opposite side of the phosphor layer of the second dichroic filter, and scatters while transmitting the outgoing light that has exited the second dichroic filter. Since the light scattering layer to be integrated is integrated, the phosphor filter of the present invention is used as the first dichroic filter as the semiconductor light emitting device. When the first visible light emitted from the semiconductor light emitting device is wavelength-converted, the first visible light emitted from the semiconductor light emitting device is output with no color unevenness regardless of the viewing angle as shown below. It can be emitted as incident light.

That is, the first dichroic filter and the second dichroic filter constituting the phosphor filter of the present invention selectively transmit or reflect light having a specific wavelength with respect to light traveling in the thickness direction.
The emitted light emitted through the phosphor filter of the present invention is the first visible light emitted without being wavelength-converted in the phosphor filter and the second visible light generated by wavelength conversion in the phosphor filter. Are mixed colors.

The first visible light incident on the phosphor filter is emitted in all directions when the wavelength of the first visible light is converted to the second visible light by the phosphor of the phosphor layer. Of the second visible light obtained from the phosphor layer, the second visible light incident on the second dichroic filter at an angle within the critical angle range is emitted from the second dichroic filter.
The first visible light incident on the second dichroic filter is incident on the second dichroic filter after passing through the first dichroic filter after passing through the first dichroic filter and proceeding in the thickness direction of the phosphor filter without being wavelength-converted by the phosphor. Since it is reflected by the two-dichroic filter, it is not emitted in the thickness direction of the phosphor filter. For this reason, the light emitted from the second dichroic filter in the thickness direction of the phosphor filter lacks the amount of the first visible light mixed with the second visible light, and is a color corresponding to the wavelength of the second visible light. It becomes light with a taste.

  On the other hand, when light traveling in a direction inclined with respect to the thickness direction is incident on the first dichroic filter or the second dichroic filter, the distance that the light passes through the first dichroic filter or the second dichroic filter is in the thickness direction. Since the traveling light is different from the incident light, the spectral characteristics of the first dichroic filter or the second dichroic filter are different. That is, the second dichroic filter reflects the first visible light traveling in the thickness direction, but transmits light having a shorter wavelength as the incident angle increases for light traveling in a direction inclined with respect to the thickness direction.

Therefore, the light enters the first dichroic filter from the direction inclined with respect to the thickness direction, passes through the first dichroic filter, passes through the phosphor layer without being wavelength-converted to the second visible light, The light incident on the second dichroic filter in the tilting direction passes through the second dichroic filter and is emitted as the first visible light. Therefore, the light emitted from the second dichroic filter in the direction inclined with respect to the thickness direction includes not only the second visible light wavelength-converted by the phosphor layer but also a lot of first visible light. It will be.
As a result, there is a problem that the light emitted from the second dichroic filter has a different color depending on the viewing angle. That is, the light emitted in the thickness direction becomes light with a color corresponding to the wavelength of the second visible light as compared with the light emitted in the direction inclined with respect to the thickness direction. On the other hand, the light emitted in the direction inclined with respect to the thickness direction becomes light having a color corresponding to the wavelength of the first visible light as compared with the light emitted in the thickness direction. For this reason, when the emitted light of the semiconductor light emitting element is emitted through the first dichroic filter, the phosphor layer, and the second dichroic filter, the color differs depending on the viewing angle.

However, in the phosphor filter of the present invention, the second dichroic filter is provided with a light scattering layer that scatters while transmitting the emitted light emitted from the second dichroic filter on the side opposite to the phosphor layer of the second dichroic filter. The light having a tint corresponding to the wavelength of the second visible light emitted from the dichroic filter in the thickness direction and the wavelength of the first visible light emitted from the second dichroic filter in a direction inclined with respect to the thickness direction. Since the light having the corresponding color is mixed in the light scattering layer, the light emitted from the semiconductor light emitting element can be emitted as uniform and non-uniform light regardless of the viewing angle.
Therefore, for example, when the first visible light has a peak wavelength in the range of 400 nm to 500 nm and the second visible light has a peak wavelength in the range of 500 nm to 800 nm, When the phosphor filter is disposed with the first dichroic filter facing the semiconductor light emitting element side and the wavelength of the first visible light emitted from the semiconductor light emitting element is converted, the first visible light emitted from the semiconductor light emitting element is converted into a viewing angle. Regardless of, it can be emitted as white light with no color.

In addition, the phosphor filter of the present invention is provided with a light scattering layer that scatters the light emitted from the second dichroic filter while transmitting the light, so that the phosphor filter is inclined with respect to the thickness direction from the second dichroic filter. Of the oblique light emitted in the direction, the light scattering layer reflects a part of the light having a very large angle difference from the thickness direction that cannot be extracted when the light scattering layer is not provided. It can be taken out from the phosphor filter. Therefore, according to the phosphor filter of the present invention, it is possible to extract light emitted from the semiconductor light emitting element more efficiently than a phosphor filter not provided with a light scattering layer.
Furthermore, in the phosphor filter of the present invention, the first visible light that passes through the light scattering layer and proceeds in the thickness direction toward the second dichroic filter can be reflected by the second dichroic filter and returned to the light scattering layer. Therefore, the light emitted from the semiconductor light emitting element can be extracted efficiently.

  In addition, since the phosphor filter of the present invention is formed by laminating and integrating the first dichroic filter, the phosphor layer, the second dichroic filter, and the light scattering layer, the first dichroic filter is disposed on the semiconductor light emitting element side. When the first visible light emitted from the semiconductor light emitting device is wavelength-converted by arranging the phosphor filter of the present invention toward the first, the second visible light traveling from the phosphor layer to the first dichroic filter is transmitted by the first dichroic filter. It can be reflected back to the phosphor layer, and the first visible light traveling in the thickness direction that has passed through the phosphor layer without being converted can be reflected by the second dichroic filter and returned to the phosphor layer. . Therefore, even if the amount of the phosphor contained in the phosphor layer is small, the wavelength of the first visible light traveling in the thickness direction can be converted efficiently, and the amount of the phosphor contained in the phosphor layer can be reduced. it can. Therefore, the amount of light that cannot be extracted from the phosphor layer by being repeatedly totally reflected by the phosphor in the phosphor layer can be reduced, and the light emitted from the semiconductor light emitting element can be extracted more efficiently.

In addition, the phosphor filter of the present invention is formed by laminating and integrating the first dichroic filter, the phosphor layer, the second dichroic filter, and the light scattering layer. Compared with a case where a low refractive index intervening layer such as an air layer is interposed in at least one of the layers, the light emitted from the semiconductor light emitting element can be extracted efficiently.
On the other hand, for example, when an air layer is included as an intervening layer, the amount of light that cannot be extracted from the air layer increases due to total reflection of light incident on the air layer. The emitted light cannot be extracted efficiently.

  The method for producing a phosphor filter of the present invention includes a step of providing a second dichroic filter on a light scattering layer made of a resin film, a step of providing a phosphor layer on the second dichroic filter, and a phosphor layer. And a step of providing a first dichroic filter. The phosphor filter of the present invention in which the first dichroic filter, the phosphor layer, the second dichroic filter, and the light scattering layer are laminated and integrated. Easy to manufacture.

The lamp of the present invention includes a base, a semiconductor light emitting element that emits light having a wavelength of 500 nm or less, disposed on the base, and a phosphor filter that converts the wavelength of light emitted from the semiconductor light emitting element. Since the filter is the phosphor filter of the present invention, and the first dichroic filter is disposed toward the semiconductor light emitting element side, the emitted light having a wavelength of 500 nm or less emitted from the semiconductor light emitting element is related to the viewing angle. Therefore, it can be efficiently extracted as uniform and uniform light.
In addition, since the lamp of the present invention uses a semiconductor light emitting element that emits light with a wavelength of 500 nm or less, the life of the lamp is longer than that of a lamp using a semiconductor light emitting element that emits ultraviolet light. It can be used across

FIG. 1 is a schematic cross-sectional view schematically showing an example of the phosphor filter of the present invention. FIG. 2 is a graph showing the relationship between wavelength and transmittance for an example of a dielectric multilayer film used as the first dichroic filter, and shows the result of measuring the spectral characteristics of the dielectric multilayer film with a spectrophotometer. Spectrum. FIG. 3 is a graph showing the relationship between wavelength, transmittance and reflectance for an example of a dielectric multilayer film used as the second dichroic filter, and the spectral characteristics of the dielectric multilayer film were measured with a spectrophotometer. It is the spectrum which showed the result. FIG. 4 is a schematic cross-sectional view for explaining the optical path of the first visible light incident on the phosphor filter shown in FIG. FIG. 5A to FIG. 5C are schematic cross-sectional views schematically showing an example of the lamp of the present invention.

Hereinafter, a phosphor filter, a method for producing the phosphor filter, and a lamp of the present invention will be described in detail with reference to the drawings.
"Phosphor filter"
FIG. 1 is a schematic cross-sectional view schematically showing an example of the phosphor filter of the present invention. In FIG. 1, reference numeral 10 denotes a phosphor filter. In FIG. 1, the lower side of the phosphor filter 10 is the semiconductor light emitting element side, and the upper side of the phosphor filter 10 is the light emitting side.
As shown in FIG. 1, the phosphor filter 10 is formed by laminating a first dichroic filter 1, a phosphor layer 2, a second dichroic filter 3, and a light scattering layer 4.

The phosphor filter 10 shown in FIG. 1 is arranged with the first dichroic filter facing the semiconductor light emitting element side.
As the semiconductor light emitting device, for example, a device that emits light having a wavelength of 500 nm or less can be used. The peak wavelength and dominant wavelength of light emitted from the semiconductor light emitting element having a wavelength of 500 nm or less are not particularly limited. For example, an LED element that emits blue light having a peak wavelength of 455 nm may be used as the semiconductor light emitting element. it can.

  The first dichroic filter 1 transmits the first visible light out of the vertical light traveling in the thickness direction of the phosphor filter 10 (vertical direction in FIG. 1), and the second visible light having a longer wavelength than the first visible light. Is reflected. The first dichroic filter 1 transmits 70% or more, more preferably 80% or more, of the first visible light incident from the semiconductor light emitting element side, and the wavelength of the first visible light incident from the phosphor layer 2 is converted. It is preferable that 90% or more, more preferably 95% or more of the second visible light is reflected.

In the phosphor filter 10 shown in FIG. 1, the wavelength of the first visible light is a wavelength including the wavelength range of light emitted from the semiconductor light emitting element. The first visible light preferably has a peak wavelength in the range of 400 nm to 500 nm, and more preferably has a peak wavelength in the range of 435 nm to 480 nm.
The second visible light preferably has a peak wavelength in the range of 500 nm to 800 nm, and more preferably has a peak wavelength in the range of 530 nm to 600 nm. The second visible light may include light having a peak wavelength in the range of 500 nm to 580 nm and light having a peak wavelength in the range of 600 nm to 750 nm.

  The phosphor layer 2 is laminated on the opposite side of the first dichroic filter 1 from the semiconductor light emitting element (on the first dichroic filter 1 in FIG. 1). The phosphor layer 2 includes a phosphor (not shown in FIG. 1) that converts the wavelength of the first visible light into the second visible light, and a part of the first visible light transmitted through the first dichroic filter 1. Is converted into second visible light having a longer wavelength than the first visible light. As the phosphor layer 2, a light-transmitting resin containing a phosphor is used.

The phosphor layer 2 is not particularly limited as long as the phosphor layer 2 converts the wavelength of the first visible light into the second visible light having a wavelength longer than that of the first visible light. YAG (Yttrium Aluminum Garnet) which radiates | emits blue light as yellow light with a peak wavelength of 560 nm wavelength-converted by receiving blue light with an incident peak wavelength of 460 nm can be used.
Further, as a phosphor, when receiving blue light having a peak wavelength of 460 nm incident on the phosphor layer 2 and being excited, green light having a peak wavelength of 520 nm obtained by wavelength conversion of the blue light, red light having a peak wavelength of 650 n, and For example, a silicate phosphor that emits light containing light may be used.

  The light-transmitting resin is not particularly limited, but a coating liquid containing a phosphor dispersed in the light-transmitting resin can be formed, and the phosphor can be formed by applying and curing the coating liquid. What can form the layer 2 is preferably used. Specifically, for example, a silicone resin or a transparent epoxy resin is preferably used as the light transmissive resin.

  The thickness of the phosphor layer 2 and the particle size of the phosphor contained in the phosphor layer 2 are not particularly limited. Moreover, it is preferable that the fluorescent substance layer 2 is unevenly distributed in the one surface side of the fluorescent substance layer 2 rather than the fluorescent substance disperse | distributing uniformly to the fluorescent substance layer 2 whole. . When the phosphor is unevenly distributed on one surface side of the phosphor layer 2, among the light incident on the phosphor layer 2, the light is repeatedly refracted and reflected by the phosphor and the light scattering layer 4 side of the phosphor filter 10. The amount of light that can no longer be extracted can be reduced, and the blue light emitted from the semiconductor light emitting element can be efficiently extracted via the phosphor filter 10.

  The second dichroic filter 3 is laminated on the opposite side of the phosphor layer 2 from the first dichroic filter 1 (on the phosphor layer 2 in FIG. 1). The second dichroic filter 3 reflects the first visible light that passes through the phosphor layer 2 and proceeds in the thickness direction, and transmits the second visible light. The second dichroic filter 3 reflects 90% or more, more preferably 95% or more of the first visible light that passes through the phosphor layer 2 and is incident, and the first visible light incident from the phosphor layer 2 It is preferable that the second visible light having undergone wavelength conversion transmit 70% or more, more preferably 85% or more.

  Furthermore, in the present embodiment, one or both of the second dichroic filter 1 and the first dichroic filter 3 includes a low refractive index film (not shown) and a high refractive index having a higher refractive index than the low refractive index film. It is preferably a dielectric multilayer film formed by alternately laminating a plurality of films (not shown). By forming the second dichroic filter 1 and / or the first dichroic filter 3 from a dielectric multilayer film, an excellent second having a high reflectance and a high transmittance selectively with respect to light of a predetermined wavelength. The dichroic filter 1 and / or the first dichroic filter 3 can be realized.

Examples of the low refractive index film constituting the dielectric multilayer film include an SiO ₂ film and an MgF ₂ film. Examples of the high refractive index film include a TiO ₂ film, a Ta ₂ O ₅ film, and an Nb ₂ O ₅ film. As the dielectric multilayer film used here, it is preferable to use a dielectric multilayer film in which a SiO ₂ film as a low refractive index film and a Ta ₂ O ₅ film as a high refractive index film are alternately laminated several tens of times. Note that the wavelength characteristics of the dielectric multilayer film as the second dichroic filter 1 or the first dichroic filter 3 include the refractive index and film thickness of each low refractive index film and each high refractive index film constituting the dielectric multilayer film. Determined by selection. For example, since the optical thin film basically has an optical film thickness nd = λ / 4, if the film thickness is about several tens of nm, the film thickness d and the refractive index n can be determined from the reflectance spectrum.

FIG. 2 is a graph showing the relationship between wavelength and transmittance for an example of a dielectric multilayer film used as the first dichroic filter, and shows the result of measuring the spectral characteristics of the dielectric multilayer film with a spectrophotometer. Spectrum. The graph shown in FIG. 2 shows a dielectric multilayer film in which a SiO ₂ film as a low refractive index film and a Ta ₂ O ₅ film as a high refractive index film are alternately laminated 30 times on a quartz substrate. Is the spectrum. As shown in FIG. 2, the dielectric multilayer film transmits light (first visible light) having a wavelength of 500 nm or less (transmits 80% or more) and light having a wavelength exceeding 500 nm (second visible light). Is reflected (reflects 95% or more) (not transmitted), and can be preferably used as the first dichroic filter 1. The film thickness of the SiO ₂ film is 117 nm, and the film thickness of the Ta ₂ O ₅ film is 80 nm.

FIG. 3 is a graph showing the relationship between wavelength, transmittance and reflectance for an example of a dielectric multilayer film used as the second dichroic filter, and the spectral characteristics of the dielectric multilayer film were measured with a spectrophotometer. It is the spectrum which showed the result. The graph shown in FIG. 3 shows a dielectric multilayer film in which a SiO ₂ film as a low refractive index film and a Ta ₂ O ₅ film as a high refractive index film are alternately laminated 30 times on a quartz substrate. Is the spectrum. As shown in FIG. 3, the dielectric multilayer film reflects light (first visible light) having a wavelength of 500 nm or less (reflects 95% or more) and light exceeding the wavelength 500 nm (second visible light). Is transmitted (70% or more is transmitted), and can be preferably used as the second dichroic filter 3.

  The light scattering layer 4 is laminated on the side opposite to the phosphor layer 2 of the second dichroic filter 3 (on the second dichroic filter 3 in FIG. 1), and scatters while transmitting the outgoing light emitted from the second dichroic filter 3. It is something to be made. Therefore, in the phosphor filter 10 of the present embodiment, the vertical light transmitted through the second dichroic filter 3 and the oblique light transmitted through the second dichroic filter 3 are scattered and mixed by the light scattering layer 4. It has become.

  The light scattering layer 4 may be any material as long as the light emitted from the second dichroic filter 3 can be scattered while being transmitted, but in order to obtain a phosphor filter 10 that can be easily manufactured, a resin film It is preferable that it consists of. The light scattering layer 4 made of a resin film is preferably made of a resin film having a plurality of irregularities. In this case, it is more preferable that the plurality of irregularities constituting the light scattering layer 4 is formed only on the surface of the light scattering layer 4 opposite to the second dichroic filter 3. When a plurality of irregularities are formed only on the surface of the light scattering layer 4 opposite to the second dichroic filter 3, the plurality of irregularities are formed only on the surface of the light scattering layer 4 on the second dichroic filter 3 side. Compared with the case, the scattering effect by the light-scattering layer 4 is effectively obtained, and the light incident on the phosphor filter 10 can be efficiently extracted.

The light scattering layer 4 may be made of a resin base material, a resin base material integrated with the resin base material, and a plurality of particles having different refractive indexes, or a plurality of bubbles. It may consist of a resin film containing.
The material of the resin film used for the light scattering layer 4 is not particularly limited, but light transmissive properties such as polyethylene terephthalate (PET), silicone resin, acrylic resin, transparent epoxy resin, amorphous cycloolefin resin, and polycarbonate resin. It is preferable to use a resin.

Examples of the resin film having a plurality of irregularities used as the light scattering layer 4 include those having a plurality of irregularities formed on the surface by roughening the surface of the resin film.
Examples of the resin film containing a plurality of bubbles include a resin film containing bubbles formed by containing scattering particles made of hollow glass particles or the like inside the resin film. In this case, it is preferable that the hollow scattering particles are laid only in one layer so as not to overlap each other inside the resin film. As a result, light is scattered by the light scattering layer 4, so that light traveling in a direction near the direction perpendicular to the thickness direction of the phosphor filter 10 is generated, and light that cannot be extracted from the phosphor filter 10 is generated. Can be prevented.
Moreover, as the resin film containing a plurality of bubbles, a resin film containing bubbles formed using a foaming technique inside the resin film may be used.

The transmittance of the light scattering layer 4 is preferably as high as possible, and is not particularly limited. For example, the spectral transmittance at 600 nm is preferably 50% or more, and more preferably 60% or more. Moreover, it is preferable that the haze value of the light-scattering layer 4 is 70% or more, and it is more preferable that it is 80% or more.
The light scattering layer 4 is specifically made of, for example, polyethylene terephthalate (PET) having an average thickness of 51 μm, and the heat shrinkage ratio before and after heating at 150 ° C. for 0.5 hour is 1% or less at 600 nm. Those having a spectral transmittance of 64.5% and a haze value of 81.4% can be preferably used. Examples of such a light scattering layer 4 include D114SIII (trade name: manufactured by Tsujiden Co., Ltd.).

"Light path of light"
Next, the first visible light emitted from the semiconductor light emitting element is incident from the first dichroic filter 1 side (lower side in FIG. 1) of the phosphor filter 10 shown in FIG. 1, and the light scattering layer 4 side (FIG. 1). The optical path of light emitted from the upper side will be described with reference to the drawings.
FIG. 4 is a schematic cross-sectional view for explaining the optical path of the first visible light incident on the phosphor filter 10 shown in FIG. As shown in FIG. 4, when the first visible lights a to c emitted from the semiconductor light emitting element are incident on the phosphor filter 10 from the first dichroic filter 1 side, the first visible light a to c is transmitted through the first dichroic filter 1 to fluoresce. Reach body layer 2. The first visible light a and the first visible light b out of the first visible light a to c reaching the phosphor layer 2 are absorbed by the phosphor 2a included in the phosphor layer 2 and are converted into a wavelength of the second visible light Y. Converted.

More specifically, as shown in FIG. 4, the first visible light a is absorbed by the phosphor 2 a and wavelength-converted into a1 to a4 that are the second visible light Y.
As shown in FIG. 4, the wavelength-converted second visible light Y a <b> 1 and a <b> 3 passes through the second dichroic filter 3 and reaches the light scattering layer 4. The second visible light a <b> 1 is not vertical light that travels in the thickness direction of the phosphor filter 10 in the phosphor layer 2, but is oblique light that travels in a direction inclined with respect to the vertical light, and enters the light scattering layer 4. Has reached. The second visible light a <b> 3 is converted into vertical light in the phosphor layer 2 and reaches the light scattering layer 4.

Further, as shown in FIG. 4, the wavelength-converted second visible light Y a <b> 2 is totally reflected by the phosphor 2 a, travels toward the first dichroic filter 1, and is reflected by the first dichroic filter 1. It is returned to the phosphor layer 2, passes through the second dichroic filter 3, and reaches the light scattering layer 4.
Further, as shown in FIG. 4, the wavelength-converted second visible light Y a4 is totally reflected a plurality of times by the phosphor 2a and converted into the second visible light Y, and then the second dichroic filter 3 is used. And reaches the light scattering layer 4.

  Further, as shown in FIG. 4, the first visible light b passes through the phosphor layer 2 without being converted into the second visible light Y by the phosphor 2 a and reaches the second dichroic filter 3. . Then, the first visible light b reaching the second dichroic filter 3 is reflected by the second dichroic filter 3, returned to the phosphor layer 2, and wavelength-converted to the converted light Y by the phosphor 2a. Thereafter, the first visible light b converted into the converted light Y is transmitted through the second dichroic filter 3 and reaches the light scattering layer 4 as shown in FIG.

  Further, as shown in FIG. 4, the first visible light c passes through the phosphor layer 2 without being wavelength-converted to the second visible light Y by the phosphor 2a, and remains in the first visible light c as the second dichroic. The filter 3 is reached. The second dichroic filter 3 reflects the first visible light out of the vertical light transmitted through the phosphor layer 2 and transmits the second visible light. Since the first visible light c that has reached the second dichroic filter 3 is oblique light, as shown in FIG. 4, the first visible light c passes through the second dichroic filter 3 without being reflected by the second dichroic filter 3, and It reaches the light scattering layer 4 with visible light B as it is.

  As described above, when the first visible lights a to c emitted from the semiconductor light emitting element pass through the second dichroic filter 3 and reach the light scattering layer 4, only the second visible light Y is used for the oblique light. Since much first visible light B is also included, the oblique light becomes light with a color corresponding to the wavelength of the first visible light as compared with the vertical light. For this reason, when the light transmitted through the second dichroic filter 3 is emitted from the phosphor filter 10 without being transmitted through the light scattering layer 4, the color varies depending on the viewing angle, and color unevenness occurs.

In the phosphor filter 10 shown in FIG. 4, the vertical light and the oblique light that have reached the light scattering layer 4 are scattered and mixed while being transmitted by the light scattering layer 4. Therefore, as shown in FIG. 4, the light emitted from the phosphor filter 10 becomes light W having no color unevenness regardless of the viewing angle.
For example, the first visible light has a peak wavelength in the range of 400 nm to 500 nm, the second visible light has a peak wavelength in the range of 500 nm to 800 nm, and the phosphor shown in FIG. When the filter 10 is disposed with the first dichroic filter 1 facing the semiconductor light emitting element and the wavelength of the first visible light emitted from the semiconductor light emitting element is converted, the first visible light emitted from the semiconductor light emitting element is It is emitted as white light with no color regardless of the angle. More specifically, when the first visible light emitted from the semiconductor light emitting element reaches the light scattering layer 4, it corresponds to the colored vertical light corresponding to the wavelength of the second visible light and the wavelength of the first visible light. The oblique light having a tinged color is scattered and mixed while being transmitted by the light scattering layer 4, and is emitted as white light having no color regardless of the viewing angle.

  Further, a part of the first visible light B reaching the light scattering layer 4 becomes vertical light traveling toward the second dichroic filter 3 by being scattered by the light scattering layer 4, but the second dichroic filter 3. The light is reflected by the light scattering layer 4 and returned to the light scattering layer 4, and is again scattered and utilized by the light scattering layer 4.

"Method of manufacturing phosphor filter"
Next, a method for manufacturing the phosphor filter 10 shown in FIG. 1 will be described.
First, the light scattering layer 4 made of a resin film is formed. Next, the second dichroic filter 3 is provided on the light scattering layer 4 made of a resin film.
In addition, when the light-scattering layer 4 is a resin film which has a several unevenness | corrugation only on one side, it is preferable to provide the 2nd dichroic filter 3 in the surface side which does not have the unevenness | corrugation of the light-scattering layer 4. By doing in this way, it becomes the structure by which the several unevenness | corrugation which comprises the light-scattering layer 4 is formed only in the surface on the opposite side to the 2nd dichroic filter 3 of the light-scattering layer 4, and has a predetermined spectral characteristic. The phosphor filter 10 that includes the second dichroic filter 3 and the light scattering layer 4 that effectively obtains the scattering effect and can efficiently extract the light incident on the phosphor filter 10 can be formed.

  When the second dichroic filter 3 is formed on the non-protruding surface side of the light scattering layer 4 made of a resin film having a plurality of concavities and convexities only on one side, compared with the case where the second dichroic filter is formed on the surface side having the unevenness. Thus, the film thickness of the second dichroic filter 3 becomes uniform, and the second dichroic filter 3 having a predetermined spectral characteristic can be easily obtained. On the other hand, when the second dichroic filter 3 is formed on the uneven surface side of the light scattering layer 4 made of a resin film having a plurality of unevenness only on one side, the variation in film thickness increases and the phosphor filter 10 The second dichroic filter 3 has many portions that are not perpendicular to the thickness direction, and the second dichroic filter 3 having spectral characteristics as designed may not be obtained.

Next, the phosphor layer 2 is provided on the second dichroic filter 3 by a method of applying and curing a coating solution made of a resin containing the phosphor. When the phosphor layer 2 is formed such that the phosphor is unevenly distributed on one surface side of the phosphor layer 2, for example, a low-viscosity material in which phosphors having a relatively large particle size are dispersed. It is preferable to form the phosphor layer 2 using a method in which a coating solution is applied and cured. In this case, it is preferable to use a phosphor having an average particle diameter of 5 μm or more as the phosphor having a relatively large particle diameter, and it is preferable to use a low-viscosity coating liquid having a viscosity of 10 Pa · s or less.
Next, the first dichroic filter 1 is provided on the phosphor layer 2 in the same manner as the method of forming the second dichroic filter 3. Through the above steps, the phosphor filter 10 shown in FIG. 1 is obtained.

In the method for manufacturing the phosphor filter 10 of the present embodiment, the first dichroic filter 1 and the second dichroic filter 3 are formed by alternately forming a low refractive index film and a high refractive index film a plurality of times, and a dielectric multilayer film. It is preferable to form by forming.
In addition, as a film-forming method for forming the 1st dichroic filter 1 and the 2nd dichroic filter 3, physical vapor deposition methods (PVD method), such as a vacuum evaporation method, sputtering method, and ion plating method, chemical vapor deposition method ( CVD method) can be used, but it is preferable to use a method capable of forming a film at a low temperature that does not adversely affect the resin film constituting the light scattering layer 4 such as deformation. It is preferable to use a method capable of forming a film at a low temperature. Of the above film formation methods, the sputtering method is preferable because it is suitable for film formation at a low temperature. As the sputtering method, it is particularly preferable to use a method of forming a film at a low temperature of 200 ° C. or lower using a digital sputtering apparatus Ardis (ULDiS) (trade name: manufactured by ULVAC, Inc.).

"lamp"
FIG. 5A to FIG. 5C are schematic cross-sectional views schematically showing an example of the lamp of the present invention. Each of the lamps 21, 22, and 23 shown in FIGS. 5A to 5C converts the wavelength of the LED element 5 (semiconductor light emitting element) disposed on the substrate and the emitted light of the LED element 5. The phosphor filter 10 shown in FIG. 1 is provided, and the phosphor filter 10 is disposed with the first dichroic filter 1 facing the LED element 5 side.

  The LED element 5 is not particularly limited as long as it emits light having a wavelength of 500 nm or less. For example, an LED element 5 in which a gallium nitride based semiconductor layer is formed on a substrate made of sapphire or the like is preferably used. . In the lamps 21, 22, and 23 shown in FIGS. 5A to 5C, the LED element 5 that emits light having a wavelength of 400 to 500 nm is used. Therefore, ultraviolet light is emitted as the LED element. Compared to lamps using lamps, they have a long life and can be used for a long time.

  The lamp 21 shown in FIG. 5A includes the reflector 6. The reflector 6 has a sealing portion 7 for accommodating the LED element 5 disposed on a base (not shown). A phosphor filter 10 is installed on the reflector 6 so as to cover the sealing portion 7. The sealing portion 7 has, for example, a circular concave shape in plan view, and the LED element 5 is installed at the bottom. The inside of the sealing portion 7 may be sealed by being filled with a sealing resin, or may be sealed, but is preferably sealed. When the inside of the sealing portion 7 is sealed by filling the sealing resin, there is no air layer between the LED element 5 and the phosphor filter 10, and the LED element 5 and the phosphor filter 10. Compared to the case where an air layer exists between the two, the lamp 21 has an excellent light extraction efficiency.

The lamp 21 shown in FIG. 5A includes the LED element 5 that emits blue light, and the phosphor filter 10 that is disposed with the first dichroic filter 1 facing the LED element 5 side. The light emitted from the element 5 can be efficiently extracted as uniform and uniform color light regardless of the viewing angle.
Further, in the lamp 21 shown in FIG. 5A, sufficiently high light extraction is possible without improving the light extraction efficiency by highly controlling the material of the reflector 6 and the shape of the sealing portion 7. Since efficiency is obtained, the design conditions of the reflector 6 can be relaxed.

  In the lamp 21 shown in FIG. 5A, the phosphor filter 10 is installed on the reflector 6 so that the first dichroic filter 1 faces the LED element 5 so as to cover the sealing portion 7. Therefore, the color of the light emitted from the lamp 21 can be controlled by the phosphor filter 10, and the light emitted from the lamp 21 by filling the sealing portion 7 with a sealing resin containing the phosphor. There is no need to adjust the color, and the step of filling the sealing resin can be omitted, and it can be easily manufactured.

  The lamp 22 shown in FIG. 5 (b) has a recess 8a for accommodating the LED element 5 on the substrate 8 (base). The LED element 5 is installed at the bottom of the recess 8a. The recess 8a may or may not be filled with sealing resin. A phosphor filter 10 is installed on the edge of the recess 8a so that the first dichroic filter 1 faces the LED element 5 so as to cover the recess 8a. As shown in FIG. 5B, the phosphor filter 10 may be provided individually so as to cover each recess 8a, but is provided integrally so as to continuously cover the adjacent recess 8a. It may be done.

  Similarly to the lamp 21 shown in FIG. 5A, the lamp 22 shown in FIG. 5B is also arranged with the LED element 5 emitting blue light and the first dichroic filter 1 facing the LED element 5 side. Since the phosphor filter 10 is provided, the light emitted from the LED element 5 can be efficiently extracted as uniform and non-uniform color light regardless of the viewing angle.

Further, in the lamp 22 shown in FIG. 5B, the phosphor filter 10 is installed with the first dichroic filter 1 facing the LED element 5 so as to cover the recess 8a. The color of the light emitted from the lamp 21 can be controlled, and it is not necessary to adjust the color of the light emitted from the lamp 22 by filling the recess 8a with a sealing resin containing a phosphor. The step of filling the sealing resin can be omitted and can be easily manufactured.
Further, in the lamp 22 shown in FIG. 5B, since the concave portion 8a for accommodating the LED element 5 is provided on the substrate 8, it is easily formed as compared with the case where a reflector or the like is formed. it can.

  The lamp 23 shown in FIG. 5C is formed on the substrate 9 (base), and the first dichroic filter 1 is directed toward the LED element 5 so as to cover the LED element 5 arranged on the substrate 9. The phosphor filter 10 is installed. In addition, as shown in FIG.5 (c), although the phosphor filter 10 may be provided individually so that each LED element 5 may be covered, it integrates so that the adjacent LED element 5 may be covered continuously. It may be provided.

Similarly to the lamp 21 shown in FIG. 5A, the lamp 23 shown in FIG. 5C is also arranged with the LED element 5 emitting blue light and the first dichroic filter 1 facing the LED element 5 side. Since the phosphor filter 10 is provided, the light emitted from the LED element 5 can be efficiently extracted as uniform and non-uniform color light regardless of the viewing angle.
Further, in the lamp 23 shown in FIG. 5C, the phosphor filter 10 is installed so as to cover the LED element 5 formed on the substrate 9, so that the phosphor filter 10 emits the light from the lamp 21. The color of the emitted light can be controlled, and it is not necessary to form a reflector, which can be easily formed as compared with the case of forming a reflector or the like.

  DESCRIPTION OF SYMBOLS 1 ... 1st dichroic filter, 2 ... Phosphor layer, 2a ... Phosphor, 3 ... 2nd dichroic filter, 4 ... Light scattering layer, 5 ... LED element, 6 ... Reflector, 7 ... Sealing part, 8, 9 ... Substrate (base), 8a... Recess, 10... Phosphor filter, a, b, c, B... First visible light, a1, a2, a3, a4, Y. …lamp.

Claims (12)

A first dichroic filter that transmits the first visible light and reflects the second visible light having a longer wavelength than the first visible light;
A phosphor layer that is laminated on the first dichroic filter and includes a phosphor that converts the wavelength of the first visible light into the second visible light;
A second dichroic filter that is laminated on the opposite side of the phosphor layer from the first dichroic filter, reflects the first visible light traveling in the thickness direction, and transmits the second visible light;
A semiconductor light emitting device, wherein a light scattering layer that is laminated on a side opposite to the phosphor layer of the second dichroic filter and that scatters while transmitting the emitted light emitted from the second dichroic filter is integrated. Phosphor filter for element.   One or both of the second dichroic filter and the first dichroic filter are dielectric layers in which a plurality of low refractive index films and a plurality of high refractive index films having a higher refractive index than the low refractive index film are alternately stacked. The phosphor filter according to claim 1, wherein the phosphor filter is made of a multilayer film.   The phosphor filter according to claim 1 or 2, wherein the phosphor is unevenly distributed on one surface side of the phosphor layer.   The first visible light has a peak wavelength in a range of 400 nm to 500 nm, and the second visible light has a peak wavelength in a range of 500 nm to 800 nm. The phosphor filter according to claim 1.   The phosphor filter according to any one of claims 1 to 4, wherein the light scattering layer is made of a resin film having a plurality of projections and depressions.   The phosphor filter according to claim 5, wherein the plurality of irregularities are formed only on a surface of the light scattering layer opposite to the second dichroic filter.   The said light-scattering layer consists of a resin film containing the resin base material, the said resin base material integrated with the said resin base material, and several particle | grains from which a refractive index differs. 4. The phosphor filter according to any one of 4 above.   The phosphor filter according to any one of claims 1 to 4, wherein the light scattering layer is made of a resin film containing a plurality of bubbles. It is a manufacturing method of the fluorescent substance filter in any one of Claims 1-8,
Providing the second dichroic filter on a light scattering layer made of a resin film;
Providing a phosphor layer on the second dichroic filter;
Providing the first dichroic filter on the phosphor layer. A method for producing a phosphor filter, comprising:   10. The method of manufacturing a phosphor filter according to claim 9, wherein one or both of the second dichroic filter and the first dichroic filter are provided by forming a film at a temperature of 200 ° C. or less.   11. The method according to claim 9, wherein the step of providing the phosphor layer includes a step of applying and curing a coating liquid made of a resin containing a phosphor on the second dichroic filter. Manufacturing method of phosphor filter. A substrate, a semiconductor light emitting element that emits light having a wavelength of 500 nm or less disposed on the substrate, and a phosphor filter that converts the wavelength of the emitted light of the semiconductor light emitting element,
The said fluorescent filter is a fluorescent substance filter in any one of Claims 1-8, Comprising: The said 1st dichroic filter is arrange | positioned toward the said semiconductor light emitting element side, The lamp | ramp characterized by the above-mentioned. .

Images