JP7182450B2 - light emitting device - Google Patents

Description

The present invention relates to a light-emitting device including light-emitting elements such as light-emitting diodes.

2. Description of the Related Art Conventionally, light-emitting devices including light-emitting elements such as light-emitting diodes have been known. For example, Patent Literature 1 discloses a light-emitting device including a light-emitting element and a light-transmitting member that transmits light emitted from the light-emitting element.

JP 2010-219324 A

The light-emitting element performs a light-emitting operation when supplied with power. A light-emitting device is provided with, for example, electrodes and wiring for power supply to a light-emitting element. Further, the light-emitting device is provided with, for example, functional elements such as resistors and capacitors in addition to the light-emitting elements. Then, the light-emitting device is attached to various devices and systems using the light-emitting device while the various elements and wiring are protected and sealed.

In addition, light emitting devices are required to have different optical characteristics, for example, different optical output ranges, depending on the application and customer. Moreover, even if the device is designed so as to satisfy the required optical characteristics, there are cases where an individual that does not satisfy the optical characteristics is produced due to other factors such as manufacturing process tolerances.

However, in the case of light-emitting devices, it is often difficult to change the light-emitting elements and other functional elements after packaging, for example, sealing. Therefore, for example, it is difficult to adjust a light-emitting device whose optical characteristics are out of the acceptable range in a finished product inspection so that it falls within the acceptable range after the inspection, or to change the optical characteristics of the light-emitting device at the customer's site. often.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light-emitting device whose optical characteristics can be easily adjusted after mounting.

A light-emitting device according to the present invention comprises a substrate, a light-emitting element arranged on the substrate, and a plurality of metal oxide particles provided on the substrate on the side of the light-emitting element, the light absorption characteristics of which change when irradiated with ultraviolet light. and a variable light absorber comprising:

Further, the light-emitting device according to the present invention includes a substrate, a plurality of light-emitting elements arranged side by side on the substrate, and provided on the side of each of the plurality of light-emitting elements on the substrate. and a variable light absorber comprising a plurality of varying metal oxide particles.

1 is a top view of a light emitting device according to Example 1. FIG. 1 is a cross-sectional view of a light emitting device according to Example 1. FIG. 1 is an enlarged cross-sectional view of a light emitting device according to Example 1. FIG. 4 is a cross-sectional view of particles in the variable light absorber in the light emitting device according to Example 1. FIG. 4A to 4C are diagrams illustrating a method for manufacturing the light emitting device according to Example 1; 4A to 4C are diagrams illustrating a method for manufacturing the light emitting device according to Example 1; 4A to 4C are diagrams illustrating a method for manufacturing the light emitting device according to Example 1; 4A and 4B are diagrams showing a method for adjusting light output in the light emitting device according to Example 1. FIG. FIG. 10 is a cross-sectional view of a light-emitting device according to Modification 1 of Example 1; FIG. 10 is a cross-sectional view of a light-emitting device according to Modification 2 of Example 1; FIG. 10 is a cross-sectional view of a light emitting device according to Example 2; FIG. 11 is a cross-sectional view of a light emitting device according to Example 3;

Examples of the present invention will be described in detail below.

FIG. 1A is a schematic top view of the light emitting device 10 according to Example 1. FIG. FIG. 1B is a cross-sectional view along line 1B-1B of FIG. 1A. Moreover, FIG. 1C is an enlarged cross-sectional view showing an enlarged portion A surrounded by a dashed line in FIG. 1B. The configuration of the light emitting device 10 will be described with reference to FIGS. 1A to 1C.

The light emitting device 10 has a substrate 11 and a light emitting element 12 arranged on the substrate 11 . The light emitting device 10 also has a variable light absorber 13 provided on the side of the light emitting element 12 on the substrate 11 and capable of changing absorption of light emitted from the light emitting element 12 . The light-emitting device 10 also includes a sealing body 14 that is provided on the substrate 11 , seals the light-emitting element 12 , and transmits light emitted from the light-emitting element 12 .

In this embodiment, the light-emitting device 10 also has a frame 15 that is provided on the substrate 11 so as to be spaced apart from the light-emitting element 12 and surrounds the light-emitting element 12 . Each of the variable light absorber 13 and the sealing body 14 is provided in a region between the light emitting element 12 and the frame 15 on the substrate 11 .

Next, a detailed configuration of the light emitting device 10 will be described. In this embodiment, the substrate 11 has an insulating substrate 11A and first and second wirings 11B and 11C provided on the substrate 11A. The light emitting element 12 is bonded to the substrate 11 so as to be electrically connected to the first and second electrodes 11B and 11C.

In this embodiment, the base 11A of the substrate 11 has a plate-like shape, and first and second wirings 11B and 11C are formed on the upper surface of the base 11A. The light emitting element 12 is bonded to the upper surface of the base 11A while being in contact with the first and second wirings 11B and 11C. That is, the upper surface of the base 11 functions as a mounting surface of the light emitting element 12 on the substrate 11 .

Although not shown, in this embodiment, the first and second wirings 11B and 11C are formed on the bottom surface of the substrate 11 via through holes penetrating between the top surface and the bottom surface of the substrate 11. connected to an external terminal. However, the wiring configuration of the substrate 11 is not limited to this. It is sufficient that the light emitting element 12 is mounted on the substrate 11 .

The light emitting element 12 is, for example, a semiconductor light emitting element such as a light emitting diode. In this embodiment, the light emitting element 12 has a support substrate 12A and a semiconductor layer 12B including a light emitting layer supported by the support substrate 12A. For example, the support substrate 12A is made of a silicon substrate. Also, for example, the semiconductor layer 12B is made of a nitride-based semiconductor. Each of the light emitting elements 12 emits light with a wavelength of, for example, 420 to 470 nm (hereinafter sometimes referred to as blue light).

For example, the light emitting element 12 includes a support substrate 12A, a semiconductor layer 12B formed on the upper surface of the support substrate 12A, a first electrode (not shown) formed on the semiconductor layer 12B, and a bottom surface of the support substrate 12A. has a second electrode (not shown) formed on the .

The light emitting element 12 is mounted on the mounting surface of the substrate 11 from the bottom surface of the support substrate 12A. Also, the first electrode of the light emitting element 12 is connected to the first wiring 11B of the substrate 11 via a bonding wire such as a gold wire. Also, the second electrode is connected to the second wiring 11C of the substrate 11 via a conductive bonding member.

Note that the configuration of the light emitting element 12 is not limited to this. For example, the light emitting device 12 may have a growth substrate used for crystal growth of the semiconductor layer 12B. In this case, for example, the light emitting element 12 has a growth substrate, a semiconductor layer 12B grown on the growth substrate, and a first electrode and a second electrode formed on the semiconductor layer 12B. Also, in this case, the growth substrate of the light emitting element 12 is bonded to the substrate 11 . Also, the first and second electrodes are connected to the first and second wirings 11B and 11C of the substrate 11 via bonding wires.

As another configuration of the light emitting element 12, the semiconductor layer 12B may be placed on the mounting surface of the substrate 11. FIG. In this case, the light emitting element 12 has first and second electrodes formed on the semiconductor layer 12B. Also, the first and second electrodes of the light emitting element 12 are bonded to the substrate 11 via a conductive bonding member (also called flip-chip bonding). In this case, the semiconductor layer 12B is arranged on the substrate 11, and the translucent support substrate 12A or the growth substrate used for crystal growth of the semiconductor layer 12B is arranged on the semiconductor layer 12B.

In this embodiment, the light-emitting element 12 has a rectangular (square in this embodiment) top shape when viewed from a direction perpendicular to the mounting surface of the light-emitting element 12 on the substrate 11 . However, the top surface shape of the light emitting element 12 is not limited to a rectangular shape, and may be various shapes such as a circular shape, an elliptical shape, and a rectangular shape. In this embodiment, the upper surface of the light emitting element 12 (for example, the surface of the semiconductor layer 12B or the support substrate 12A opposite to the substrate 11) functions as the light extraction surface of the light emitting element 12. FIG.

The variable light absorber 13 is configured such that its light absorbency changes as it is irradiated with ultraviolet light. For example, the variable light absorber 13 is composed of titanium oxide particles and a medium (matrix) containing the titanium oxide particles, as described later. In this embodiment, the variable light absorber 13 is formed in layers on the side of the light emitting element 12 on the substrate 11 .

The titanium oxide particles in the variable light absorber 13 change in quality when irradiated with ultraviolet light, and change, for example, the absorption of light emitted from the light emitting element 12 . In this embodiment, the variable light absorber 13 absorbs the light emitted from the light emitting element 12 in one region and transmits or scatters the light in another region.

In this embodiment, the variable light absorber 13 is provided on the substrate 11, is not irradiated with ultraviolet light, and is titanium oxide particles that scatter and reflect the light emitted from the light emitting element 12. In contrast, it has a region (hereinafter referred to as a scattering reflection region) 13SC containing titanium oxide particles having no absorptivity.

Also, the variable light absorber 13 is provided at a position farther from the substrate 11 than the scattering reflection region 13SC, in the present embodiment, near the upper surface 13S of the variable light absorber 13, and emits light when irradiated with ultraviolet light. It has a region (hereinafter referred to as an absorption region) 13AB containing titanium oxide particles that absorb light emitted from the element 12 .

The sealing body 14 is provided on the substrate 11 so as to embed the light emitting element 12 and the variable light absorber 13 therein. In this embodiment, the encapsulant 14 completely covers the top surface and side surfaces of the light emitting element 12 and the top surface 13S of the variable light absorber 13 . In addition, the sealing body 14 has insulating properties and translucency with respect to the light emitted from the light emitting element 12 . For example, the sealing body 14 is made of silicone resin.

The frame 15 is arranged on the substrate 11 so as to be in contact with the side surfaces of the variable light absorber 13 and the sealing body 14 and to surround the light emitting element 12 while being separated from the light emitting element 12 . The frame body 15 is made of, for example, a resin body containing titanium oxide particles at a higher concentration than the variable light absorber 13 .

Note that the frame 15 functions as a member that defines a mounting region of the light emitting element 12 on the substrate 11 and a sealing region of the light emitting element 12 with the sealing body 14 . The sealing body 14 is provided in a region inside the frame body 15 . However, the sealing body 14 may cover a part of the upper surface of the frame 15, or may cover the entire frame 15 (may bury the frame 15). Also, the frame 15 may not be provided.

The variable light absorber 13 will be described in detail below. The variable light absorber 13 is sealed together with the light emitting element 12 by a sealing body 14 . In this embodiment, the variable light absorber 13 is in contact with the sealing body 14 on the upper surface 13S and in contact with the light emitting element 12 on the inner surface. In addition, in this embodiment, the variable light absorber 13 is in contact with the substrate 11 at its bottom surface, and is in contact with the frame body 15 at its outer surface. Note that the variable light absorber 13 may be arranged on the side of the light emitting element 12 on the substrate 11, and is not limited to the arrangement shown in FIG.

Next, the internal structure of the variable light absorber 13 will be described with reference to FIGS. 1C and 1D. FIG. 1D is a schematic cross-sectional view of particles contained in the variable light absorber 13. FIG. First, as shown in FIG. 1C, the variable light absorber 13 includes a plurality of titanium oxide particles dispersed in the variable light absorber 13 (first, second and third titanium oxide particles P1, P2 and P3 are shown).

In this embodiment, the variable optical absorber 13 includes a medium that disperses the particle group 13PT. Examples of the medium include thermosetting silicone resins and epoxy resins. That is, the variable light absorber 13 is made of a resin containing particles. In addition, in this embodiment, the resin body as the medium has a property of transmitting visible light. In this embodiment, the medium of the variable light absorber 13 is in contact with the substrate 11, the light emitting element 12, the sealing body 13, and the like.

Further, as shown in FIG. 1D, each of the first to third titanium oxide particles P1 to P3 includes titanium oxides P10, P20 and P30 and titanium oxide (particle bodies) P10, P20 and P30, respectively. and covering films P11, P21 and P31.

Specifically, in this example, the first titanium oxide particles P1 have titanium oxide P10 and a coating film P11 that covers the surface of the titanium oxide P10 and protects the titanium oxide P10. The coating film P11 is, for example, a film made of an organic substance such as alumina, silica, or polyol. Similarly, the second and third titanium oxide particles P2 and P3 each have titanium oxides P20 and P30 and coating films P21 and P31 covering the surfaces of the titanium oxides P20 and P30.

Next, as shown in FIG. 1D, in the particle group 13PT, each of the first and third titanium oxide particles P1 and P3 has more particles (inside each titanium oxide P10 and P30) than other portions. It has a small bandgap portion P00. The portion P00 is a portion of titanium oxide lacking oxygen. The portion P00 is hereinafter referred to as an oxygen-deficient portion.

In addition, as shown in FIG. 1C, in the present embodiment, the particle group 13PT is arranged such that the average density of the oxygen-deficient portions P00 in each particle decreases from the upper surface 13S of the variable light absorber 13 toward the substrate 11. contains first to third titanium oxide particles P1 to P3 dispersed in For clarity of illustration, the first and third titanium oxide particles P1 and P3 are hatched in FIG. 1C. In this embodiment, each of the titanium oxide particles P1 to P3 consists of titanium dioxide (TiO ₂ ) P10, P20 and P30 having a rutile crystal structure.

The density of the oxygen-deficient portions P00 in each of the first to third titanium oxide particles P1 to P3 is, for example, the ratio of the oxygen-deficient portions P00 in each particle. This is the area occupied by the oxygen-deficient portion P00 on the surface of P30.

In the present embodiment, first titanium oxide particles P1 dispersed in a region (hereinafter sometimes referred to as a first region) 13A on the uppermost surface 13S side in the variable light absorber 13 in the particle group 13PT. has an oxygen-deficient portion P00 at the highest density (first density).

For example, the oxygen-deficient portion P00 of the first titanium oxide particles P1 has a bandgap energy smaller than the energy of visible light (more specifically, the energy of the wavelength of visible light). For example, in this embodiment, the oxygen vacancy P00 in the first titanium oxide particles P1 has a bandgap energy (for example, about 1 .5 eV).

Further, among the particle groups 13PT, the second titanium oxide particles P2 dispersed in the region 13B closest to the substrate 11 in the variable light absorber 13 (hereinafter sometimes referred to as the second region) have the lowest It has an oxygen-deficient portion P00 at a density (second density).

For example, the second titanium oxide particles P2 have almost no oxygen vacancies P00, as shown in FIG. 1D. Therefore, for example, the second titanium oxide particles P2 have bandgap energy higher than the energy of the light emitted from the light emitting element 12 in any portion (almost all).

For example, when the second titanium oxide particles P2 (titanium oxide P20) have a rutile crystal structure, the second titanium oxide particles P2 have a bandgap energy of 3.0 eV. When the second titanium oxide particles P2 have an anatase-type crystal structure, the second titanium oxide particles P2 have a bandgap energy of 3.2 eV.

Further, in the particle group 13PT, the third titanium oxide particles P3 dispersed in the region 13C between the first and second regions 13A and 13B (hereinafter sometimes referred to as the third region) It has an oxygen-deficient portion P00 which is smaller than the titanium oxide particles P1 and has a higher density (third density (a density between the first density and the second density)) than the second titanium oxide particles P2.

It is understood that titanium oxide crystals have a smaller bandgap due to oxygen deficiency. More specifically, oxygen vacancies form an intermediate level between the valence band and conduction band of titanium oxide. The bandgap referred to here is the energy gap between this intermediate level and the valence band or conduction band.

Here, the bandgap (local bandgap in each particle) of the first to third titanium oxide particles P1 to P3 will be described. A crystal with a bandgap has the optical property of absorbing light of wavelengths with energies greater than its bandgap energy and transmitting light of wavelengths with energies less than this energy.

In this example, the oxygen vacancy P00 in each of the first and third titanium oxide particles P1 and P3 has a bandgap energy smaller than the bandgap energy corresponding to the wavelength of visible light.

For example, the energy of light with a wavelength of 450 nm (blue light, in air) is about 2.76 eV, and the energy of light with a wavelength of 630 nm (red light, in air) is about 1.67 eV. . As described above, the first and third titanium oxide particles P1 and P3 contain oxygen vacancies P00 having a bandgap energy of 1.5 eV. Therefore, each of the first and third titanium oxide particles P1 and P3 absorbs visible light due to the oxygen deficiency portion P00.

On the other hand, each of the second titanium oxide particles P2 does not (almost do not) have an oxygen-deficient portion P00. That is, almost all of the second titanium oxide particles P2 have a bandgap energy of 3.0 eV (for example, in the case of rutile type). Therefore, the second titanium oxide particles P2 function as scattering reflection particles that do not absorb visible light, and transmit and scatter visible light.

In this example, the first and third titanium oxide particles P1 and P3 (the first and third regions 13A and 13C) absorb visible light under observation using white visible light. Therefore, it has a black or gray color. In addition, in this example, the second titanium oxide particles P2 (second regions 13B) are white under observation using white visible light.

In other words, in this embodiment, the first and third regions 13A and 13C function as absorption regions 13AB that absorb visible light. On the other hand, the second region 13B functions as a scattering reflection region 13SC that scatters and reflects visible light.

Also, in this embodiment, the first and third titanium oxide particles P1 and P3 are dispersed only in a predetermined depth region near the upper surface 13S of the variable light absorber 13. FIG. For example, the first and third titanium oxide particles P1 and P3 are dispersed only in a region within a thickness (depth) range of 20 μm or less from the upper surface 13S. Therefore, the variable light absorber 13 functions as an absorption region 13AB in the vicinity of the upper surface 13S, and functions as a scattering reflection region 13SC inside thereof.

Further, in this embodiment, the first to third titanium oxide particles P1 to P3 are dispersed in the variable light absorber 13 (inside the medium) with a uniform dispersion density as a whole. However, the first to third titanium oxide particles P1 to P3 may be dispersed such that the dispersion density (content) gradually increases from the upper surface 13S of the variable light absorber 13 toward the substrate 11. . For example, the particle groups 13PT may be dispersed at a higher density in a region (lower region) of the variable light absorber 13 near the substrate 11 than in a region (upper region) near the upper surface 13S.

The first, second and third titanium oxide particles P1, P2 and P3 have coating films P11, P21 and P31, respectively. As a result, the first to third titanium oxide particles P1 to P3 can be endowed with resistance to yellowing due to ultraviolet rays (yellowing resistance) and weather resistance. However, the first to third titanium oxide particles P1 to P3 may not have the coating films P11 to P31 if resistance to yellowing due to ultraviolet rays and weather resistance are not required.

2A, 2B, and 2C are diagrams showing each step of the method for manufacturing the light emitting device 10. FIG. Each of FIGS. 2A-2C is a cross-sectional view similar to FIG. 1A during each step. FIG. 3 is a flowchart showing a method for manufacturing the light emitting device 10. As shown in FIG. A method for manufacturing the light emitting device 10 will be described with reference to FIGS. 2A to 2C and 3. FIG.

First, FIG. 2A shows a substrate 11 on which a light-emitting element 12, a variable light absorber 13P having no absorption region 13AB (hereinafter also referred to as a variable light absorber), a sealing body 14, and a frame body 15 are formed. FIG. 4 is a diagram showing; In this embodiment, first, the substrate 11 (the substrate 11A on which the first and second wirings 11B and 11C are formed) is prepared, and the frame 15 is fixed to the substrate 11 (FIG. 3, step S11). The substrate 11 to which the frame 15 is fixed in advance may be prepared, or the substrate 11 and the frame 15 may be integrally molded.

Next, the light emitting element 12 is mounted on the substrate 11 (FIG. 3, step S12). Subsequently, the variable light absorber 13P is formed on the substrate 11 between the light emitting element 12 and the frame 15 (FIG. 3, step S13).

In this embodiment, a silicone resin containing titanium oxide particles P0 similar to the second titanium oxide particles P2 is filled and heated for a short period of time to temporarily harden (a state in which the intermolecular cross-linking of the silicone resin is insufficient). ) to form the variable light absorber 13P. In this example, rutile-type titanium dioxide having an average particle diameter of 250 nm and a bandgap energy of 3.0 eV was used as the titanium oxide particles P0. The concentration of the titanium oxide particles P0 in the variable light absorber 13P was set to 16 wt%.

Next, the light emitting element 12 is sealed (FIG. 3, step S14). In this example, the area inside the frame 15 on the substrate 11 was filled with translucent silicone resin so as to embed the light emitting element 12 and the variable light absorber 14 therein. Then, the sealing body 14 was formed by heating the silicone resin to fully cure it.

In addition, in this embodiment, ultraviolet light is used for adjusting the light absorptance of the variable light absorber 13 . Therefore, in this example, a resin material having translucency to both ultraviolet light and visible light was used as the sealing member 14 .

FIG. 2B is a diagram showing the substrate 11 in which the upper surface 13S of the variable light absorber 13P is irradiated with the ultraviolet light LB. In this embodiment, after the sealing step S14, the output of light extracted from the sealing body 14 is measured (FIG. 3, step S15). Then, based on the measurement result of the light output, the variable light absorber 13P is irradiated with the ultraviolet light LB to adjust the light absorption rate of the variable light absorber 13P.

Specifically, it is determined whether or not the result of the measurement step S15 is the desired result, in this embodiment, whether or not the desired optical output is obtained (FIG. 3, step S16). If the desired light output is obtained, there is no need to adjust the light output, and thus the light emitting device 10 is completed.

On the other hand, when the desired light output is not obtained, the variable light absorber 13P is irradiated with the ultraviolet light LB to adjust the light absorption rate of the variable light absorber 13P (FIG. 3, step S17). In this example, while supporting the substrate 11, the variable light absorber 13P was irradiated from outside the sealing body 14 with a laser beam having a peak wavelength in the ultraviolet region as the ultraviolet light LB. In this example, a laser light source LS that emits laser light with a wavelength of 355 nm was prepared. Further, the laser beam is emitted from the surface of the sealing body 14 toward the variable light absorber P while scanning. As a result, the ultraviolet light LB is transmitted through the sealing body 14 and irradiated to the variable light absorber 13P.

In this example, the variable light absorber 13P was irradiated with a laser beam having a beam diameter of φ45 μm and an output of 50 kW/cm ² while being moved at a speed of 1000 mm/sec. The energy of light with a wavelength of 355 nm is approximately 3.5 eV, and the bandgap energy of rutile-type titanium dioxide is 3.0 eV. Therefore, the energy of the ultraviolet light LB is greater than the bandgap energy of the titanium oxide particles P0. Therefore, the ultraviolet light LB is absorbed by the titanium oxide particles P0.

As a result, the titanium oxide particles P0 irradiated with the ultraviolet light LB are altered, and oxygen atoms within the particles are eliminated. Also, the ultraviolet light LB is intensively irradiated to the titanium oxide particles P0 in the vicinity of the upper surface 13PS of the variable light absorber 13P. Accordingly, titanium oxide particles with the greatest amount of oxygen vacancies are generated near the upper surface 13PS of the variable light absorber 13P, and titanium oxide particles with smaller degrees of oxygen vacancies are generated with increasing distance from the upper surface 13PS.

As a result, the titanium oxide particles P0 irradiated with relatively strong ultraviolet light LB in the vicinity of the upper surface 13PS of the variable light absorber 13P become high-density titanium oxide particles having oxygen-deficient portions P00, that is, the first titanium oxide particles. becomes P1. The titanium oxide particles P0 slightly separated from the upper surface 13PS of the variable light absorber 13P become the third titanium oxide particles P3 having relatively few oxygen-deficient portions P00.

Further, when separated from the upper surface 13PS by a predetermined distance (a distance at which the ultraviolet light LB is blocked by the titanium oxide particles P0), the ultraviolet light LB is not irradiated and the titanium oxide particles P0 are not degraded. Therefore, for example, the titanium oxide particles P0 existing in the vicinity of the substrate 11 become titanium oxide particles having almost no oxygen vacancies P00, that is, the second titanium oxide particles P2.

In this manner, the irradiation of the ultraviolet light LB forms the variable light absorber 13 containing a plurality of titanium oxide particles (particle group 13PT) dispersed so that the density of the oxygen-deficient portion P00 gradually decreases ( Figure 2C). The variable light absorber 13 irradiated with the ultraviolet light LB has an absorption region 13AB in the vicinity of the upper surface 13S, and a scattering reflection region 13SC closer to the substrate 11 than the absorption region 13AB.

The variable light absorber 13 has a higher light absorptance than the variable light absorber 13P before being irradiated with the ultraviolet light LB. Accordingly, in this embodiment, the output of light extracted from the sealing body 14 is reduced by irradiation with the ultraviolet light LB. That is, in this embodiment, by irradiating the variable light absorber 13P with the ultraviolet light LB, it is possible to perform output adjustment for reducing the light output. Further, after the ultraviolet light LB irradiation step (step S17), the light output is measured again (step S15), and the output can be adjusted repeatedly until the desired output is obtained.

Therefore, the light-emitting device 10 is irradiated with the ultraviolet light LB and has the variable light absorber 13 having the absorption region 13AB, or is not irradiated with the ultraviolet light LB and has only the titanium oxide particles P0 (only the scattering reflection region 13SC). has a variable light absorber 13P having The light emitting device 10 manufactured in this way has a stable light output.

In the step of irradiating the ultraviolet light LB (step S17), other materials such as the medium of the variable light absorber 13 or 13P (for example, silicone resin), the sealing member 14, the frame 15, etc. are not changed. It is preferable to adjust the output of the LS. For example, by irradiating ultraviolet light (laser light) LB under the conditions described above, it is possible to alter only the titanium oxide particles P0 while suppressing alteration of other materials.

The inventors of the present application have found that the laser light under these conditions (and the output within the range of 25 to 75 kW/cm ² ) modifies the medium of the variable light absorber 13, the silicone resin as the sealant 14, and the frame 15. I'm sure it won't let you. For example, it is preferable to use a silicone resin having a transmittance of 60% or more for light with a wavelength of 355 nm as the medium of the variable light absorber 13 .

Considering that the density of the oxygen-deficient portion P00 is stably adjusted by the irradiation of the ultraviolet light LB, the concentration of the particle group 13PT (for example, the titanium oxide particles P0) is preferably 30 wt% or less, more preferably 20 wt%. More preferably:

For example, when the titanium oxide particles P0 are contained at a concentration higher than 30 wt %, it becomes difficult to form the oxygen-deficient portion P00 in the titanium oxide particles P0 even when the ultraviolet light LB is irradiated under the above conditions. This is because there are many cases. This is thought to be due to the fact that in the medium in which the titanium oxide particles P0 are dispersed at a concentration higher than 30 wt %, the ultraviolet light LB is scattered over a wide range before oxygen deficiency occurs in the titanium oxide particles P0. Therefore, when the concentration of the titanium oxide particles P0 is higher than 30 wt %, it may not be possible to stably adjust the light absorbance.

The frame 15 is made of silicone resin having titanium oxide particles P0 at a concentration higher than that of the variable light absorber 13 or 13P, for example, 70 to 90 wt %. In this case, the frame 15 functions as a member that reflects light with a high reflectance and improves the efficiency of extracting light emitted from the light emitting element 12 from the sealing body 14 . This frame 15 does not cause oxygen deficiency (does not turn black) even when irradiated with ultraviolet light LB, and maintains the scattering reflectivity of visible light. The variable light absorber 13 and the frame 15 differ at least in this point.

Moreover, the titanium oxide particles P0 may have the concentration described above in the vicinity of the upper surface 13S, and the concentration inside thereof is not limited to 30 wt % or less. For example, the variable light absorber 13 may have titanium oxide particles P0 with a concentration of 30 wt % or less in the vicinity of the upper surface 13S and titanium oxide particles P0 with a concentration higher than 30 wt % in the vicinity of the substrate 11. good. For example, it may be dispersed at a concentration of 30 wt % or less in a region of a predetermined depth from the upper surface 13S of the variable light absorber 13 .

Further, the particle size (average particle size) of the titanium oxide particles P0 is preferably, for example, within the range of 150 to 350 nm, considering the adjustment of good light absorption by the ultraviolet light LB.

Specifically, the average particle size of the particle group 13PT (titanium oxide particles P0) is 1 to 1/4 of the wavelength of light (visible light) within the variable light absorber 13 (for example, the wavelength within the silicone resin). By setting it within the range of the degree, Mie scattering with a high backscattering ratio can be generated, and extremely good scattering reflection can be obtained. In addition, by adjusting the average particle size of the particles in the particle group 13PT, the light is scattered and the light is taken in and absorbed by the particles with a high probability, so the light absorption rate can be adjusted well. .

In addition to the ease of light absorption adjustment, the titanium oxide particles P0 function as good visible light scattering particles in a state in which they are not irradiated with the ultraviolet light LB. Considering the reflectivity, the titanium oxide particles P0 preferably have an average particle size within the range of 200 to 300 nm.

The variable light absorber 13 has, for example, a particle configuration suitable for changing the light absorptance by irradiation with the ultraviolet light LB, as described above. As a result, the variable light absorber 13 becomes a member whose light output can be easily adjusted after sealing.

Note that the method for manufacturing the light emitting device 10 is not limited to this. For example, a particle-containing resin that becomes the variable light absorber 13P is applied, allowed to stand still for a predetermined time, and then heated to settle the titanium oxide particles P0. As a result, it is possible to form the variable light absorber 13 in which the titanium oxide particles P0 on the upper surface 13S side have a low dispersion density.

As described above, this embodiment has the variable light absorber 13 having the particle group 13PT including the titanium oxide particles P0 whose light absorption characteristics are changed by irradiation with the ultraviolet light LB. Therefore, after the light emitting element is sealed, for example, after completion or shipment, for example, the customer can easily adjust the light output. Therefore, it is possible to provide the light emitting device 10 whose optical characteristics can be easily adjusted after mounting.

Further, in this embodiment, the resin body, which is the dispersion medium of the particle groups 13PT in the variable light absorber 13, is integrally formed. That is, for example, the variable light absorber 13 has one resin matrix supporting each of the first to third titanium oxide particles P1 to P3. Further, there is no medium boundary between the first to third regions 13A to 13C. Therefore, the mechanical strength of the variable light absorber 13 is maintained even when the absorption region 13AB is provided. Therefore, the variable light absorber 13 and the light emitting device 10 are of high quality and long life.

Moreover, the particle group 13PT has a uniform dispersion density as a whole within the variable light absorber 13 . Therefore, each of the first to third titanium oxide particles P1 to P3 is dispersed in the variable light absorber 13 with a density within a range comparable to each other. Therefore, even when the absorption region 13AB is provided, the thermal expansion coefficient of the variable light absorber 13 as a whole is made uniform, thereby maintaining the mechanical strength of the variable light absorber 13. FIG. Therefore, the variable light absorber 13 and the light emitting device 10 are of high quality and long life.

Incidentally, as described above, the dispersion density of the particle groups 13PT within the variable light absorber 13 may gradually decrease toward the substrate 11 . For example, when the dispersion density of the first to third titanium oxide particles P1 to P3 on the substrate 11 side is increased and the dispersion density of the first to third titanium oxide particles P1 to P3 on the upper surface 13S side is decreased, , the adhesion of the interface between the upper surface 13S of the variable light absorber 13 and the sealing body 14 is improved. Therefore, for example, even when a high-output laser beam is irradiated as the ultraviolet light LB several times, it is possible to prevent the variable light absorber 13 and the sealing member 14 from peeling off.

For example, when performing step S13 described above, a particle-containing resin having a content of titanium oxide particles P0 of 32% by weight is used, and the titanium oxide particles P0 are allowed to stand still to settle and then hardened. An absorber 13P is formed. In this case, the concentration of the titanium oxide particles (first titanium oxide particles P1) in the vicinity of the upper surface 13S of the variable light absorber 13 can be adjusted to a concentration suitable for adjusting the light absorptance, for example, about 16 wt%. . In this case, the light absorption characteristics in the absorption region 13AB and the light scattering characteristics in the scattering reflection region 13SC in the vicinity of the upper surface 13S can be maintained, and the adhesion between the variable light absorber 13 and the sealing body 14 is improved. It is possible to

Further, in this embodiment, the variable light absorber 13 has thermosetting silicone resin having a refractive index within the range of 1.4 to 1.55 as the resin medium. Also, the particle group 13PT includes, for example, anatase-type titanium oxide particles having a refractive index of approximately 2.5 or rutile-type titanium oxide particles having a refractive index of approximately 2.7. Considering obtaining high scattering reflectivity in the scattering reflection region 13SC, the particle group 13PT (titanium oxide particles P0 or P2) preferably has a higher refractive index than the resin medium.

Further, as shown in FIG. 1D, each of the first to third titanium oxide particles P1 to P3 has a coating film P11 to P31 (that is, the titanium oxide particle P0 used for forming each particle is coated). By using the ultraviolet light LB, for example, a high-output laser with a wavelength of 355 nm, the oxygen vacancies P00 can be effectively and stably generated on the surface of each of the titanium oxides P10 to P30. Therefore, the absorption region 13AB can be stably formed in a desired region.

FIG. 4 is a cross-sectional view of a light-emitting device 10A according to Modification 1 of Example 1. FIG. The light emitting device 10A has the same configuration as the light emitting device 10 except for the configuration of the variable light absorber 16. FIG. In this modified example, the variable light absorber 16 has an absorption region 16AB only in a partial region on the upper surface 16S. That is, the variable light absorber 16 has the scattering reflection area 16SC in a partial area of the upper surface 16S.

In this modification, the variable light absorber 16 has a scattering reflection region 16SC in a region other than the absorption region 16AB including part of the upper surface 16S. Note that the absorption region 16AB has the same particles and medium as the absorption region 13AB, and the scattering reflection region 16SC has the same particles and medium as the scattering reflection region 13SC.

As in this modification, the variable light absorber 16 has the absorption region 16AB only in a partial region of the upper surface 16S, and has the scattering reflection region 16SC in the other region. For example, when a position on the substrate 11 suitable for light output adjustment is known, or when performing local output adjustment such as suppressing intensity unevenness, only a part of the variable light absorber 16 is irradiated with ultraviolet light. The absorption region 16AB may be formed only in that portion by irradiating the light LB. In this case, the light-emitting device 10A in which the absorption region 16AB is formed only on a part of the surface of the variable light absorber 16 is manufactured. Other regions of the upper surface 16S are reflective regions in this modification.

Note that the variable light absorber 16 does not necessarily need to be provided with the absorption region 16AB. This is because, for example, when there is no need to adjust the light output, there is no need to irradiate the ultraviolet light LB. Both of the variable light absorbers 13 and 16 have almost no absorptivity as a whole and function as light reflectors when the ultraviolet light LB is not irradiated. As a result, the light emitting device 10 or 10A, which has a high output and is capable of adjusting the light output, is obtained.

In other words, the variable light absorber 13 or 16 changes its light absorption characteristics between a state in which it hardly absorbs light and a state in which it does absorb light. The variable light absorber 13 or 16 is a particle-containing body that functions as a light output adjuster that adjusts the light output by irradiation with the ultraviolet light LB in the light emitting device 10 or 10A.

FIG. 5 is a cross-sectional view of a light-emitting device 10B according to Modification 2 of Embodiment 1. FIG. The light-emitting device 10B has the same configuration as the light-emitting device 10 except for the configurations of the light-emitting element 12F and the sealing body 17. FIG. The light emitting device 10B has a light emitting element 12F mounted by flip chip bonding. The light emitting element 12F has a semiconductor layer 12B arranged on the substrate 11, and a support substrate 12A arranged on the semiconductor layer 12B.

Further, the light emitting device 10B has a plate-like sealing body 17 fixed to the upper surface of the frame body 15 . The sealing body 17 is not in contact with the light emitting element 12</b>F and the variable light absorber 13 and seals the space above the substrate 11 formed by the frame body 15 . The encapsulant 17, like the encapsulant 14, has translucency to light emitted from the light emitting element 12 and ultraviolet light. The sealing body 17 is made of a material such as glass or acrylic resin, for example.

For example, the sealing body 17 is fixed to the frame body 15 with an adhesive. Further, the light-emitting device 10B is provided with the exception that the variable light absorber 13P is sufficiently heated and completely cured in step S13, and then a glass plate or the like as the sealing member 17 is adhered to the frame 15 in step S14. Alternatively, it can be manufactured by a process similar to that shown in FIG.

Further, as in this modification, the light emitting device 10 may have a light emitting element 12F mounted by flip chip bonding. In other words, even when the light emitting element 12 has various configurations, it is possible to adjust the light output after sealing.

Note that even when various light-emitting elements 12 are formed, the variable light absorber 13 preferably has a height within a range that does not cover the side surface of the light-emitting layer in the semiconductor layer 12B of the light-emitting element 12 . For example, the variable light absorber 13 is preferably formed on the substrate 11 with a height not exceeding the light emitting layer of the light emitting element 12 . This is because, when the absorption region 13AB is formed in the variable light absorber 13, if the absorption region 13AB covers the side surface of the light emitting layer, the light output is greatly reduced.

On the other hand, when adjusting the light output to a large extent, the variable light absorber 13 may be intentionally formed so as to cover the side surface of the light emitting layer of the light emitting element 12 . For example, when the absorption region 13AB is formed so as to cover the side surface of the light emitting layer, the light output is much lower than when the absorption region 13AB is provided along the upper surface 13S under the light emitting layer.

In other words, for example, the light output can be coarsely adjusted by adjusting the formation region of the variable light absorber 13 as a whole, and the light output can be finely adjusted by adjusting the region forming the absorption region 13AB. It can be performed.

In this embodiment, the case where the variable light absorber 13 has the absorption region 13AB that absorbs visible light and the scattering reflection region 13SC that reflects visible light has been described. However, the configuration of the variable light absorber 13 is not limited to this. For example, the light emitting element 12 may have a configuration that emits light in a band other than visible light. In this case, the absorption region 13AB and the scattering reflection region 13SC of the variable light absorber 13 only need to have absorbability and reflectivity, respectively, with respect to light in the other wavelength band.

In other words, for example, the particles in the variable light absorber 13, their bandgap configurations, and the medium should be adjusted so that the light absorption characteristics for the light emitted from the light emitting element 12 are changed.

Also, in this case, considering the effective provision of the absorption region 13AB within the variable light absorber 13, for example, the titanium oxide particles in the particle group 13PT absorb the emitted light from the light emitting element 12 within the variable light absorber 13. (the wavelength in the medium in which the particle group 13PT is dispersed).

Also, in this embodiment, the case where the absorption region 13AB has the first and third titanium oxide particles P1 and P3 has been described, but the configuration of the particle group 13PT is not limited to this. For example, the particle group 13PT may be composed of only two types of titanium oxide particles P1 and P2.

In this case, for example, the average density of the oxygen-deficient portions P00 in the first titanium oxide particles P1 dispersed in the first region 13A near the upper surface 13S of the variable light absorber 13 in the variable light absorber 13 is It is sufficient that the average density of the oxygen vacancies P00 in the second titanium oxide particles P2 dispersed in the second region 13B on the substrate 11 side of the first region 13A is higher than the average density.

Further, for example, as described above, there are cases where the adjustment itself of the optical output is not performed. In this case, for example, the particle group 13PT may include the second titanium oxide particles P2, that is, the titanium oxide particles P0 that are not irradiated with the ultraviolet light LB. In other words, the variable light absorber 13 only needs to have a plurality of titanium oxide particles whose light absorption characteristics change when irradiated with the ultraviolet light LB.

Further, the particles forming the particle group 13PT are not limited to titanium oxide particles. For example, zinc oxide (ZnO) has properties similar to titanium oxide. For example, zinc oxide has a bandgap energy of 3.37 eV and is transparent to visible light. Zinc oxide also has the property of absorbing ultraviolet light LB with a wavelength of 355 nm. Furthermore, the refractive index of zinc oxide is 2.0, which is greater than the refractive index of silicone resin (1.4 to 1.55). Zinc oxide has the property of absorbing visible light by forming a deep donor level due to oxygen deficiency to reduce the bandgap.

Therefore, the particle group 13PT, such as titanium oxide particles and zinc oxide particles, scatters or reflects light of a predetermined wavelength such as visible light in a crystal state with no oxygen deficiency, and absorbs the light of the wavelength due to the oxygen deficiency. Metal oxide crystals with properties can be used. For example, metal oxide particles having such properties may be substituted for the titanium oxide particles P0 or P1 to P3, or may be added to the particle group 13PT. That is, the variable light absorber 13 may have, for example, a plurality of metal oxide particles whose bandgap is changed by irradiation with ultraviolet light LB.

In addition, other particles that scatter the light emitted from the light emitting element 12 are added to the particle group 13PT, in addition to particles such as titanium oxide particles or zinc oxide particles whose bandgap is changed by irradiation with the ultraviolet light LB. good too. The other particles include metal carbides such as silicon carbide (SiC), silicon nitride (Si ₂ N ₃ ), gallium nitride (GaN), aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), and metal carbides. Examples include particles of oxides, metal nitrides, and the like.

Also, the particle group 13PT may include particles having properties other than light scattering properties. For example, the particle group 13PT may contain thixotropic nano-sized silica or alumina particles. For example, when using the variable light absorber 13P to which thixotropic particles are added, sedimentation of the titanium oxide particles P0 before curing is suppressed to form the variable light absorber 13 in which the titanium oxide particles P0 are uniformly dispersed. can be done.

In other words, the variable light absorber 13 may contain, as the particle group 13PT, at least a plurality of metal oxide particles whose light absorption characteristics are changed by irradiation with the ultraviolet light LB. For example, when the particle group 13PT contains a plurality of particles including particles other than titanium oxide particles and zinc oxide particles, the plurality of particles are dispersed in the variable light absorber 13 at a uniform density, or It suffices if they are dispersed so that the density gradually increases from 13S toward the substrate 11 . Also, for example, all the particles included in the particle group 13PT may be dispersed at the above concentration.

Moreover, in this embodiment, the case where the titanium oxide particles P0 are dispersed throughout the variable light absorber 13 has been described. However, the variable light absorber 13 may contain, in at least a part of its region, a plurality of metal oxide particles whose light absorption characteristics are changed by irradiation with the ultraviolet light LB. Further, for example, when the ultraviolet light LB is irradiated, among the metal oxide particles dispersed in the variable light absorber 13, the metal oxide particles to which the ultraviolet light LB reaches cause oxygen deficiency, thereby causing the absorption region to 13AB will be formed.

Also, in this embodiment, the case where the variable light absorber 13 has the absorption region 13AB and the scattering reflection region 13SC has been described. However, the variable light absorber 13 may be configured so as to be able to form the absorption region 13AB by irradiation with the ultraviolet light LB, for example.

Therefore, for example, the variable light absorber 13 is formed in a region (for example, the first and third regions 13A and 13C) at a predetermined depth from the upper surface 13S of the variable light absorber 13, and emits light when irradiated with the ultraviolet light LB. It is only necessary to have an absorption region 13AB containing a plurality of metal oxide particles (for example, titanium oxide particles P1 and P3) that absorb light emitted from the element 12. FIG.

Further, considering obtaining high light extraction efficiency, the variable light absorber 13 is provided, for example, closer to the substrate 11 (for example, the second region 13B) than the absorption region 13AB, and the light emitted from the light emitting element 12 is It is preferable to have a scattering reflection region 13SC that includes a plurality of metal oxide particles (eg, titanium oxide particles P2) that are scattering and reflecting with respect to light.

Further, for example, when the optical output can be adjusted with a high degree of freedom and adjustment width, for example, the variable light absorber 13 is preferably formed in layers on the substrate 11 . This allows, for example, not only a global adjustment of the light output, but also a local adjustment.

Moreover, in this embodiment, the case where the light emitting device 10 has the sealing body 14 has been described. However, the light emitting device 10 is not limited to having the encapsulant 14 . For example, if the light emitting element 12 and the first and second wirings 11B and 11C of the substrate 11 are electrically protected, the sealing body 14 may not be provided.

In this way, for example, the light-emitting device 10 includes a substrate 11, a light-emitting element 12 arranged on the substrate 11, and arranged on the side of the light-emitting element 12 on the substrate 11, and the light absorption characteristic is changed by irradiation with the ultraviolet light LB. and a variable light absorber 13 comprising a plurality of metal oxide particles with varying . Therefore, it is possible to provide the light emitting device 10 whose optical characteristics can be easily adjusted after mounting.

FIG. 6 is a cross-sectional view of a light emitting device 20 according to Example 2. FIG. The light-emitting device 20 has the same configuration as the light-emitting device 10 except that it has a wavelength converter 21 on which the light-emitting element 12 is formed. In this embodiment, the wavelength conversion body 21 covers the entire light emitting element 12 in a layered manner and is partially in contact with the substrate 11 .

The wavelength converter 21 contains a material that converts the wavelength of light emitted from the light emitting element 12, such as a phosphor. For example, the phosphor may be a green phosphor that converts blue light into green light, a yellow phosphor that converts blue light into yellow light, a red phosphor that converts blue light into red light, or the like. . In addition, the structure of the wavelength conversion body 21 is not limited to this. For example, the wavelength converter 21 may be a phosphor plate provided on the upper surface of the light emitting element 12 in a plate shape.

For example, in this embodiment, the wavelength converter 21 contains a YAG (yttrium aluminum garnet) phosphor. Therefore, in this embodiment, the light emitting element 12 emits blue light and the wavelength converter 21 converts the blue light into yellow light. White light generated by mixing these colors is emitted from the light emitting device 10 .

In this embodiment, the variable light absorber 22 is provided on the side of the wavelength converter 21 . The variable light absorber 22 has the same configuration as the variable light absorber 13, for example. The variable light absorber 22 has a particle group 13PT, for example titanium oxide particles P0. Also, by irradiating the variable light absorber 22 with the ultraviolet light LB, an absorption region 22AB and a scattering reflection region 22SC are formed in the variable light absorber 22 .

In the case of the light-emitting device 20 having the wavelength converter 21 as in the present embodiment, the variable light absorber 22 is composed of light emitted from the light-emitting element 12, light whose wavelength has been converted by the wavelength converter 21, or light having a wavelength converted by the wavelength converter 21. It is sufficient that the light absorbability of the generated light is changed by mixing the colors of the light.

For example, even if the variable light absorber 22 contains particles whose absorbency for only light emitted from the light emitting element 12 is changed by irradiation with the ultraviolet light LB, output adjustment or color adjustment of light extracted from the light emitting device 20 is possible. It can be performed. It should be noted that the titanium oxide particles P0 used in the variable light absorber 13 change their light absorbency with respect to visible light when irradiated with the ultraviolet light LB. Therefore, the titanium oxide particles P<b>0 can also be used as the variable light absorber 22 .

Thus, in this embodiment, the light-emitting device 20 has the wavelength converter 21 provided on the light-emitting element 12 to convert the wavelength of the light emitted from the light-emitting element 12 . In this embodiment, the variable light absorber 22 is made of a metal oxide that changes its absorption rate with respect to the light emitted from the light emitting element 12 or the light whose wavelength is converted by the wavelength converter 22 when irradiated with the ultraviolet light LB. material particles (eg titanium oxide particles P0 or zinc oxide particles). Therefore, it is possible to easily adjust the optical characteristics of a light-emitting device that is used as a light source for various applications using visible light, such as illumination, after mounting.

FIG. 7 is a cross-sectional view of a light emitting device 30 according to Example 3. FIG. The light-emitting device 30 is the same as the light-emitting device 10 except that it has a plurality of light-emitting elements 12, and has a substrate 31, a variable light absorber 32, a sealing body 33, and a frame 34 that are associated therewith. It has a similar configuration. The light emitting device 30 has a substrate 31 made up of a base 11 provided with two light emitting elements 12 and two sets of first and second wirings 11B and 11C corresponding to each of the light emitting elements 12 .

The light-emitting device 30 also has a variable light absorber 32 provided on each side of the light-emitting elements 12 on the substrate 31 . Like the variable light absorber 13, the variable light absorber 32 has a particle group 13PT and includes, for example, titanium oxide particles P0. Also, the variable light absorber 32 has an absorption region 32AB in which the light absorbency of the particles of the particle group 13PT is changed by irradiation with the ultraviolet light LB. Also, the variable light absorber 32 has a scattering reflection region 32SC similar to that of the variable light absorber 13 .

In addition, the light emitting device 30 includes a sealing body 33 that seals each of the light emitting elements 12 and the variable light absorber 32, and a sealing body 33 that surrounds each of the light emitting elements 12, the variable light absorber 32 and the sealing body 33. and a frame 34 provided on the substrate 31 .

As in this embodiment, the light emitting device 30 may have a plurality of light emitting elements 12 . Even in this case, the variable light absorber 32 contains metal oxide particles whose light absorption characteristics change when irradiated with the ultraviolet light LB, so that the light output can be easily adjusted. Therefore, it is possible to provide the light emitting device 30 whose optical characteristics can be easily adjusted after mounting.

10, 10A, 10B, 20, 30 light emitting devices 11, 31 substrate 12 light emitting elements 13, 32 variable light absorbers P0, P1, P2, P3 titanium oxide particles

Claims (13)

a substrate;
a light emitting element disposed on the substrate;
a variable light absorber provided on the substrate on the side of the light emitting element and containing a plurality of metal oxide particles whose light absorption characteristics change when irradiated with ultraviolet light ;
The variable light absorber is formed in a region with a depth of 20 μm or less from the upper surface of the variable light absorber, and includes a plurality of metal oxides having absorbency for light emitted from the light emitting element upon irradiation with ultraviolet light. A light-emitting device comprising an absorbing region containing particles . 2. The light-emitting device according to claim 1, wherein the plurality of metal oxide particles of the variable light absorber change bandgap by irradiation with ultraviolet light. 3. The light emitting device according to claim 1, wherein the variable light absorber is formed in layers on the substrate. The variable light absorber has a scattering reflection region provided closer to the substrate than the absorption region and containing a plurality of metal oxide particles that scatter and reflect light emitted from the light emitting element. The light-emitting device according to any one of claims 1 to 3 , characterized by: a wavelength converter provided on the light emitting element for converting the wavelength of light emitted from the light emitting element;
5. The light emission according to any one of claims 1 to 4 , wherein the plurality of metal oxide particles change an absorptance with respect to light whose wavelength has been converted by the wavelength converter by irradiation with ultraviolet light. Device. 6. The light emitting device according to claim 1, wherein said variable light absorber has a resin medium in which said plurality of metal oxide particles are dispersed. 7. The light emitting device according to claim 1, wherein said plurality of metal oxide particles are a plurality of titanium oxide particles or zinc oxide particles. 8. The method according to claim 7 , wherein the plurality of titanium oxide particles or zinc oxide particles are dispersed at a concentration of 30 wt % or less in a region of a predetermined depth from the upper surface of the variable light absorber. luminous device. 9. The light emitting device according to claim 7, wherein said plurality of titanium oxide particles or zinc oxide particles have an average particle size within the range of 150-350 nm. The plurality of metal oxide particles according to any one of claims 1 to 9 , wherein the plurality of metal oxide particles are dispersed in the variable light absorber so that the concentration thereof gradually increases toward the substrate. Luminescent device. 11. The structure according to any one of claims 1 to 10 , further comprising a sealing body which is provided on the substrate , seals the light emitting element and the variable light absorber, and transmits ultraviolet light. 1. The light-emitting device according to 1. The light-emitting element has a support substrate and a semiconductor layer supported by the support substrate and including a light-emitting layer,
12. The light-emitting device according to claim 1, wherein the variable light absorber is formed on the substrate with a height not exceeding the light-emitting layer of the light-emitting element. a substrate;
a plurality of light emitting elements arranged side by side on the substrate;
a variable light absorber provided on the substrate on the side of each of the plurality of light emitting elements and containing a plurality of metal oxide particles whose light absorption characteristics change due to irradiation with ultraviolet light ,
The variable light absorber is formed in a region with a depth of 20 μm or less from the upper surface of the variable light absorber, and absorbs light emitted from each of the plurality of light emitting elements by irradiation with ultraviolet light. A light emitting device comprising an absorbing region comprising a plurality of metal oxide particles .

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