JP7190890B2 - light emitting device - Google Patents

Description

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

Conventionally, there has been known a light-emitting device that combines a light-emitting element that emits light having a predetermined wavelength (emission color) and a wavelength converter that converts the wavelength of light emitted from the light source (for example, Patent Document 1). . Also, a light-emitting device in which a plurality of light-emitting elements are arranged side by side is known (for example, Patent Document 2).

JP 2010-219324 A JP 2014-236275 A

When a plurality of light-emitting elements are provided in a light-emitting device, not only high output but also low light crosstalk between the light-emitting elements may be required. As a case where less crosstalk is required, for example, there is a case where each of the light emitting elements is turned on and off independently. In this case, it is preferable that light emitted from the lit light emitting element is suppressed from entering the extinguished light emitting element.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light-emitting device that has a simple structure and suppresses light crosstalk between light-emitting regions.

A light-emitting device according to the present invention comprises a substrate, a plurality of light-emitting elements arranged side by side on the substrate, a plurality of light-transmitting members each arranged on each of the plurality of light-emitting elements, and a plurality of light-transmitting members on the substrate. a coating disposed in a region between adjacent light-transmitting members and covering side surfaces of the plurality of light-transmitting members, wherein the coating comprises a plurality of light-scattering metal oxide particles dispersed within the coating In the particle group, the metal oxide particles dispersed in the vicinity of the surface of the coating are characterized by having oxygen-deficient portions.

A 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 a region between adjacent light-emitting elements of the plurality of light-emitting elements on the substrate. a coating that covers the side surface, the coating having a particle group containing a plurality of light-scattering metal oxide particles, the metal oxide particles dispersed near the surface of the coating in the particle group is characterized by having oxygen-deficient portions.

A 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 a region between adjacent light-emitting elements of the plurality of light-emitting elements on the substrate. a coating that covers the side surface, the coating having a particle group containing a plurality of light-scattering metal oxide particles, and the coating covering a region irradiated with laser light on the surface of the coating. It is characterized by having

1 is a cross-sectional view of a light emitting device according to Example 1. FIG. 1 is a top 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 a coating 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; FIG. 4 is a diagram schematically showing light paths in the light-emitting device according to Example 1; 4 is a diagram showing light output from 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. 11 is a cross-sectional view of a light-emitting device according to Modification 3 of Example 1; FIG. 10 is a cross-sectional view of a light-emitting device according to Modification 4 of Example 1; FIG. 11 is a cross-sectional view of a light-emitting device according to Modification 5 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; FIG. 11 is a top 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 cross-sectional view of a light emitting device 10 according to Example 1. FIG. FIG. 1B is a schematic top view of the light emitting device 10. FIG. FIG. 1A is a cross-sectional view along line 1A-1A of FIG. 1B. Also, FIG. 1C is an enlarged cross-sectional view showing an enlarged portion A surrounded by a dashed line in FIG. 1A. 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 , a plurality of light-emitting elements 12 arranged side by side on the substrate 11 , and a translucent member 14 bonded to each of the light-emitting elements 12 via bonding members 13 . In this embodiment, the bottom surface of the light emitting element 12 is arranged on the top surface of the substrate 11 . Also, the bonding member 13 is in contact with the upper surface of the light emitting element 12 . Further, the bottom surface of the translucent member 14 is in contact with the top surface of the bonding member 13 .

Further, the light-emitting device 10 is formed on the substrate 11, is separated from each of the light-emitting element 12, the bonding member 13, and the light-transmitting member 14, and has a frame surrounding each of the light-emitting element 12, the bonding member 13, and the light-transmitting member 14. It has a body 15. The light-emitting device 10 also has a cover 16 that is arranged in a region between the adjacent light-transmitting members 14 on the substrate 11 and covers each side surface of the light-transmitting members 14 . Cover 16 has surface S1 exposed to the outside. In this embodiment, the cover 16 is a region on the substrate 11 inside the frame 15 and is integrally formed on the surface of the substrate 11 exposed from the light emitting element 12 .

A detailed configuration of the light emitting device 10 will be described below. First, in this embodiment, the substrate 11 is a mounting substrate having a mounting surface (mounting surface) for the light emitting element 12 and on which the light emitting element 12 is mounted. The substrate 11 also has first wiring and second wiring (not shown) formed on the mounting surface and connected to the light emitting element 12 . Further, the substrate 11 has a first connection electrode and a second connection electrode formed on a surface (rear surface) opposite to the mounting surface and electrically connected to the first wiring and the second wiring, respectively. It has electrodes (not shown).

Each of the light emitting elements 12 is, for example, a semiconductor light emitting element such as a light emitting diode. In this embodiment, each of the light emitting elements 12 has a support substrate 12A and a semiconductor layer 12B supported by the support substrate 12A and including a light emitting layer. 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 first main surface of the support substrate 12A, and a semiconductor layer 12B formed on the second main surface opposite to the first main surface of the support substrate 12A. It has first and second electrodes (not shown) formed thereon. The light emitting element 12 is mounted on the mounting surface of the substrate 11 from the second main surface. Also, the first and second electrodes are connected to the first and second electrodes of the substrate 11 via a conductive adhesive (for example, metal bump, metal eutectic member, solder, metal nano-sintered member, conductive paste, etc.). are connected to the wiring of

Further, in this embodiment, the light emitting device 10 is configured to drive each of the light emitting elements 12 independently. For example, the first electrode of each light emitting element 12 is insulated from other first electrodes. Therefore, each of the light emitting elements 12 turns on and off independently of each other.

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. Further, in this case, the growth substrate of the light emitting device 12 is adhered to the substrate 11 . The first and second electrodes of the light emitting element 12 are connected to the first and second wirings of the substrate 11 via gold wires.

As another configuration of the light emitting element 12, the semiconductor layer 12B may be mounted 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 adhesive (also called flip-chip bonding). In this case, the semiconductor layer 12B is arranged on the substrate 11, and the support substrate 12A is arranged on the semiconductor layer 12B.

In this embodiment, each of the light emitting elements 12 has a rectangular (square in this embodiment) top shape when viewed from a direction perpendicular to the surface of the substrate 11 on which the light emitting elements 12 are mounted. explain. 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 bonding member 13 has a property of transmitting light emitted from the light emitting element 12 . The joining member 13 transmits at least visible light, for example. For example, the bonding member 13 may be made of epoxy resin, silicone resin, low-melting glass, or the like. In this embodiment, the joining member 13 is made of silicone resin.

The bonding member 13 may contain a wavelength converter, such as a phosphor, that converts the wavelength of light emitted from the light emitting element 12 . 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. .

Note that the configuration of the joining member 13 is not limited to this. For example, the translucent member 13 may be composed of a metal oxide nanoparticle sintered body that transmits the light emitted from the light emitting element 12 and the light converted by the wavelength converter.

The translucent member 14 is arranged on the upper surface of the bonding member 13 . For example, the translucent member 14 has a plate-like shape. In addition, the translucent member 14 has a characteristic of transmitting light emitted from the light emitting element 12 and/or light converted by the wavelength converter, for example, a characteristic of transmitting at least visible light. For example, the translucent member 14 may be a glass plate, a sapphire plate, a YAG (yttrium-aluminum-garnet) plate, or the like.

Further, the translucent member 14 may contain a wavelength converter, such as a phosphor, that converts the wavelength of the light emitted from the light emitting element 12 . For example, as the phosphor, 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 can be used. In this embodiment, the translucent member 14 is made of a YAG plate.

In addition, the structure of the translucent member 14 is not limited to this. For example, the translucent member 14 is made of acrylic resin, polycarbonate resin, epoxy resin, silicone resin, fluororesin, or metal oxide nanoscale resin that transmits the light emitted from the light emitting element 12 and the light converted by the wavelength converter. It may be composed of a sintered body of particles.

The top surface of the translucent member 14 functions as a light extraction surface of the light emitting device 10 . In this embodiment, the top surface of the translucent member 14 has the same shape as the top surface of the light emitting element 12, for example, a rectangular shape. However, the top surface shape of the translucent member 14 is not limited to a rectangle, and may be a shape different from the top surface shape of the light emitting element 12 . Further, for example, the side surface of the translucent member 14 may be formed stepwise, or may be inclined with respect to the upper surface.

The frame 15 is arranged on the substrate 11 so as to surround the light emitting element 12 , the joining member 13 and the light transmitting member 14 while being separated from each of the light emitting element 12 , the joining member 13 and the light transmitting member 14 . Note that the frame 15 may be arranged so as to surround the outer periphery of the substrate 11 . Further, in this embodiment, the frame body 15 is formed integrally with the substrate 11 and together with the substrate 11 forms a lamp house having a recess for housing the light emitting element 12 . The frame 15 is made of, for example, an alumina compact.

The cover 16 is formed in a region on the substrate 11 outside the light emitting element 12 , the bonding member 13 and the translucent member 14 and surrounded by the frame 15 . Note that the cover 16 may cover a part of the upper surface of the frame 15 or may cover the entire frame 15 (the frame 15 may be embedded). Also, the frame 15 may not be provided, and the outer surface of the cover 16 may be exposed.

The cover 16 will be described in detail below. Cover 16 is exposed to the outside at surface S1. Specifically, the cover 16 is continuously arranged on the substrate 11 from the end of the upper surface (that is, the light extraction surface) of the translucent member 14 to the inner wall surface or the upper end surface of the frame 15 . there is Moreover, the cover 16 is formed so as to surround the side surface of the translucent member 14 .

The cover 16 includes a bottom surface in contact with the substrate 11, an inner surface in contact with the side surface of the light-transmitting member 14, an outer surface in contact with the inner wall surface of the frame 15, and an outer surface provided between the inner surface and the outer surface so as to be exposed to the outside. and a surface S1 that In addition, in the present embodiment, the covering 16 contains a thermosetting resin. Therefore, the surface S1 of the cover 16 has a shape slightly recessed toward the substrate 11 due to heat shrinkage after curing.

Also, in this embodiment, the case where the cover 16 is in contact with the entire side surface of the translucent member 14 will be described. However, the cover 16 may be in contact with only part of the side surface of the translucent member 14 . For example, the cover 16 is a part of the side surface of the light-transmitting member 14 extending from the end of the top surface (light extraction surface) of the light-transmitting member 14 to the bottom surface of the light-transmitting member 14 (that is, the side surface of the light-transmitting member 14). It may cover only the upper region).

Next, the internal structure of the cover 16 will be described with reference to FIGS. 1C and 1D. First, as shown in FIG. 1C, the coating 16 includes a plurality of titanium oxide particles dispersed within the coating 16 (first, second and third titanium oxide particles P1, P2 and P3 are shown in FIG. 1C). shown).

In this embodiment, the coating 16 contains a medium (matrix) for dispersing the particle groups 16PT. Examples of the medium include thermosetting silicone resins and epoxy resins. That is, the covering 16 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 addition, in this embodiment, the cover 16 functions as a sealing body that seals the light emitting element 12 and the wiring on the substrate 11 .

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 16PT, 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.

Further, as shown in FIG. 1C, in this embodiment, the particle group 16PT is dispersed from the surface S1 of the coating 16 toward the substrate 11 so that the average density of the oxygen-deficient portions P00 in each particle is low. first to third titanium oxide particles P1 to P3. 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 this embodiment, among the particle groups 16PT, in the first titanium oxide particles P1 dispersed in the region closest to the surface S1 in the coating 16, the oxygen-deficient portion P00 in the first titanium oxide particles P1 has the highest density (having an oxygen-deficient portion P00 at the 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, the oxygen-deficient portion P00 in the first titanium oxide particles P1 is the light emitted from the light-emitting element 12 (blue light in this embodiment) and the emitted light from the translucent member 14 (blue light and blue light in this embodiment). It has a bandgap energy (eg, about 1.5 eV) smaller than that of yellow light).

Further, among the particle groups 16PT, in the second titanium oxide particles P2 dispersed in the region closest to the substrate 11 in the coating 16, the density of the oxygen-deficient portions P00 in the second titanium oxide particles P2 is the highest. Low (has the oxygen vacancy P00 at the 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 third titanium oxide particles P3 dispersed between the first and second titanium oxide particles P1 and P2 in the particle group 16PT, the oxygen-deficient portion P00 (for example, The portion having a bandgap energy of 1.5 eV) is the density between the first titanium oxide particles P1 and the second titanium oxide particles P2 (the third density (the ratio between the first density and the second density). density between)).

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. Therefore, each of the first and third titanium oxide particles P1 and P3 absorbs visible light due to the oxygen deficiency portion P00.

In addition, the higher the density of the oxygen-deficient portions P00, the higher the absorbance of visible light. Therefore, in this example, the first and third titanium oxide particles P1 and P3 are black or gray under observation using white visible light because the visible light is absorbed. Further, since the density of the oxygen-deficient portions P00 of the first titanium oxide particles P1 is higher than that of the third titanium oxide particles P3, the first titanium oxide particles P1 exhibit a darker black or gray color than the third titanium oxide particles P3.

In the present embodiment, each of the second titanium oxide particles P2 has no (almost no) oxygen vacancies P00, and therefore transmits and scatters visible light. Therefore, in this example, each of the second titanium oxide particles P2 presents a white color under observation using white visible light.

Further, in this embodiment, the regions in which the first, second and third titanium oxide particles P1, P2 and P3 in the coating 16 are dispersed are respectively referred to as the first, second and third regions (or When the first, second and third particle layers) 16A, 16B and 16C, the first and third regions 16A and 16C are visible light absorption regions (hereinafter simply referred to as absorption regions) ) 16AB. On the other hand, the second region 16B functions as a visible light scattering/reflection region (hereinafter simply referred to as a scattering/reflection region) 16SC that scatters and reflects visible light.

Also, the first and third titanium oxide particles P1 and P3 are dispersed only in a region near the surface S1 of the coating 16. As shown in 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 surface S1. Therefore, the covering 16 functions as an absorbing region 16AB in the vicinity of the surface S1, and functions as a scattering reflecting region 16SC inside thereof.

Further, in this embodiment, the first to third titanium oxide particles P1 to P3 are dispersed in the coating 16 (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 surface S1 of the coating 16 toward the substrate 11. For example, the particle groups 16PT may be dispersed at a higher density in a region (lower region) of the covering 16 near the substrate 11 than in a region (upper region) near the surface S1.

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. A method for manufacturing the light emitting device 10 will be described with reference to FIGS. 2A to 2C.

First, FIG. 2A is a diagram showing the substrate 11 on which the light emitting element 12, the bonding member 13, the translucent member 14, the frame 15 and the particle-containing resin 16P are formed. In this embodiment, first, a plurality of light emitting elements 12 are arranged and bonded on a substrate 11 having a wiring and a frame 15 bonded thereto (step 1). Next, a silicone resin is applied as a bonding member 13 onto each of the light emitting elements 12 (step 2). Also, a YAG plate is arranged as a translucent member 14 on each of the joining members 13 and adhered (step 3).

Subsequently, a silicone resin containing titanium oxide particles P0 similar to the second titanium oxide particles P2 as the particle-containing resin 16P in the area inside the frame 15 including the area between the light-transmitting members 14 on the substrate 11. (Step 4). Then, the particle-containing resin 16P is heated and cured (step 5). In this example, rutile-type titanium dioxide having an average particle size 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 particle-containing resin 16P was set to 16 wt%.

FIG. 2B is a diagram showing the substrate 11 of the particle-containing resin 16P while the upper surface S0 of the particle-containing resin 16P is being irradiated with laser light. First, the particle-containing resin 16P is heated and cured (step 6).

Then, while supporting the substrate 11, the upper surface S0 of the particle-containing resin 16P is irradiated with the laser beam LB (step 7). In this example, a laser light source LS that emits laser light LB with a wavelength of 355 nm was prepared. Further, the upper surface S0 of the particle-containing resin 16P is irradiated with the laser beam LB while scanning.

In this example, the upper surface S0 of the particle-containing resin 16P was irradiated with a laser beam LB 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 laser beam LB is higher than the bandgap energy of the titanium oxide particles P0. Therefore, the laser beam LB is absorbed by the titanium oxide particles P0.

As a result, the titanium oxide particles P0 irradiated with the laser beam LB are altered, and oxygen atoms within the particles are eliminated. Further, by adjusting the irradiation intensity, irradiation time, focal position, etc. of the laser beam LB, the laser beam LB is irradiated only to the titanium oxide particles P0 in the vicinity of the upper surface S0. Accordingly, titanium oxide particles with the greatest amount of oxygen vacancies are generated near the top surface S0 of the particle-containing resin 16P, and titanium oxide particles with smaller degrees of oxygen vacancies are generated with increasing distance from the top surface S0.

As a result, the titanium oxide particles P0 irradiated with the laser beam LB relatively strongly in the vicinity of the upper surface S0 of the particle-containing resin 16P become titanium oxide particles having a high density and the oxygen-deficient portions P00, that is, the first titanium oxide particles P1. becomes. The titanium oxide particles P0 slightly separated from the upper surface S0 of the particle-containing resin 16P become the third titanium oxide particles P3 having relatively few oxygen-deficient portions P00.

Further, when separated from the upper surface S0 by a predetermined distance (the distance at which the laser beam LB is blocked by the titanium oxide particles), the titanium oxide particles P0 are not affected by the laser irradiation and 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 way, by laser irradiation, the coating 16 containing a plurality of titanium oxide particles (particle group 16PT) dispersed so that the density of the oxygen-deficient portion P00 gradually decreases, and the light-emitting device 10 including the same are manufactured. (Fig. 2C).

In the step of irradiating the laser beam LB (step 7), the output of the laser light source LS is adjusted so as not to alter the properties of other materials such as the medium (for example, silicone resin) of the cover 16, the bonding member 13 and the translucent member 14. Adjustments are preferably made. For example, by irradiating the laser beam 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 beam LB under this condition (and the output within the range of 25 to 75 kW/cm ² ) uses silicone resin as the medium of the cover 16, YAG as the bonding member 13, and the translucent member 14. It is confirmed that the plate is not altered. In this embodiment, a silicone resin having a transmittance of 60% or more for light with a wavelength of 355 nm is used as the medium of the cover 16 .

Note that the method for manufacturing the light emitting device 10 is not limited to this. For example, after the particle-containing resin 16P is applied and allowed to stand still for a predetermined time, the particle-containing resin 16P is heated to cause the titanium oxide particles P0 to settle. As a result, it is also possible to form the coating 16 in which the titanium oxide particles P0 on the surface S1 side have a low dispersion density.

FIG. 3 is a diagram schematically showing light paths in the light emitting device 10. As shown in FIG. First, most of the light emitted from the light-emitting element 12 passes through the bonding member 13 and the light-transmitting member 14 and exits from the upper surface (light extraction surface) of the light-transmitting member 14 like the light L1. to be taken out.

Next, the light (such as light L2) entering the scattering reflection area 16SC of the cover 16 from the side surface of the translucent member 14 is reflected by the scattering reflection area 16SC and returns to the translucent member 14 . Light such as the light L2 is extracted to the outside from the upper surface of the translucent member 14 .

On the other hand, it is assumed that part of the light that has entered the cover 16 from the area near the upper surface of the translucent member 14 propagates through the cover 16 like the light L3. Such light enters the absorbing region 16AB and is absorbed by the absorbing region 16AB.

More specifically, the light that has entered the vicinity of the surface S1 of the cover 16 propagates along the surface S1 in the vicinity of the surface S1 of the cover 16 by causing total reflection on the surface S1 of the cover 16. easier. That is, in the vicinity of the surface S1 of the cover 16, an unintended propagation path of light is likely to be formed along the surface S1. Therefore, if the entire covering 16 has scattering reflectivity, light may propagate between the adjacent translucent members 14 via the region near the surface S1 of the covering 16 . That is, the area near the surface S1 of the cover 16 is an area where light crosstalk is likely to occur between the translucent members 14, that is, between the light emitting areas.

Therefore, since the cover 16 has the absorption region 16AB in the vicinity of the surface S1, crosstalk of light between the light-emitting regions is suppressed. Also, light such as light L3 is sufficiently attenuated by entering the absorption region 16AB, even if it is not completely absorbed. Therefore, crosstalk of light is suppressed.

Most of the area of the cover 16 other than the absorption area 16AB is the scattering reflection area 16SC. Therefore, as described above, the light (light like the light L2) that attempts to enter the scattering reflection region 16SC is reflected toward the light emitting element 12 or the translucent member 14, and then extracted to the outside. Therefore, crosstalk of light is reliably suppressed in the entire covering 16 without substantially sacrificing the light output.

FIG. 4 is a diagram showing the distribution of light output from the light emitting device 10. As shown in FIG. The horizontal axis of FIG. 4 indicates the position of the light-emitting device 10 along the line 1A-1A of FIG. 1B, and the vertical axis indicates the light output (luminance normalized by the maximum value).

In FIG. 4, as a comparative example, the dashed line indicates the measurement result of the output from a light emitting device having a coating in which only the second titanium oxide particles P2 are dispersed instead of the coating 16. A solid line indicates the result.

As shown in FIG. 4, in the light-emitting device 10, compared to the light-emitting device 100, the output from the region other than the light-emitting element 12 (translucent member 14) is greatly suppressed, and the light output from the region of the light-emitting element 12 is high. is emitted. Further, it can be seen that the light intensity sharply drops to about 1/100 of the area of the light transmitting member 14 outside the light transmitting member 14 . Also, the maximum output values of the light emitting devices 10 and 100 were substantially the same.

That is, it can be seen that the light-emitting device 10 is a light-emitting device in which crosstalk of light between light-emitting regions is suppressed without lowering the output. The inventors of the present application have confirmed that light crosstalk is sufficiently suppressed even when the translucent members 14 are arranged at intervals of about 200 μm.

Thus, the covering 16 has high reflectivity for most of the light incident on the covering 16 from the light emitting element 12, the bonding member 13, and the translucent member 14. It has an absorptive property with respect to the light that has entered the vicinity of the surface S1. Therefore, the light emitting device 10 can emit light with desired light distribution characteristics without sacrificing a decrease in light output.

For example, the light-emitting device 10 is used in applications where it is preferable to change the irradiation area (for example, the light distribution area) by switching between lighting and non-lighting of each of the light-emitting elements 12, such as lighting applications such as vehicle headlights. can be In this case, it is required that the light emitted toward the irradiation area corresponding to one light emitting element 12 should not be emitted toward another irradiation area. In this embodiment, the light-emitting device 10 has a configuration suitable for such applications.

Also, the absorption region 16AB of the cover 16 can be easily formed only by adding the step of irradiating the laser beam LB (Step 7). Therefore, it is possible to easily provide the light-emitting device 10 in which crosstalk between light-emitting regions is suppressed.

Incidentally, in this embodiment, the resin body, which is the dispersion medium of the particle group 16PT, is integrally formed. That is, for example, the coating 16 has one resin matrix that supports each of the first to third titanium oxide particles P1 to P3. Further, there is no medium boundary between the first to third regions 16A to 16C. Therefore, even if the absorbing region 16AB is provided, the mechanical strength of the covering 16 is maintained, and the optical function is stabilized as described above. Therefore, the covering 16 and the light emitting device 10 are of high quality and long life.

Further, in this embodiment, the particle groups 16PT have a uniform dispersion density as a whole within the coating 16 . Therefore, each of the first to third titanium oxide particles P1 to P3 is dispersed in the coating 16 with a density within a range comparable to each other. Therefore, even if the absorbing region 16AB is provided, the thermal expansion coefficient of the covering 16 as a whole is made uniform, thereby maintaining the mechanical strength of the covering 16. FIG. Therefore, the covering 16 and the light emitting device 10 are of high quality and long life.

Note that, as described above, the dispersion density of the particle groups 16PT within the coating 16 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 surface S1 side is decreased, , resin cracks on the surface S1 of the coating 16 can be suppressed. In this case, there is a possibility that the light L3 guided near the surface S1 is increased, but the absorption region 16AB suppresses the guiding of the light L3.

More specifically, for example, when performing the step 4 described above, the particle-containing resin 16P containing 32 wt % of the titanium oxide particles P0 is used in the stationary step (the step of settling the titanium oxide particles P0). ) to form the covering 16 . Through this step, the content of the titanium oxide particles (first titanium oxide particles P1) in the vicinity of the surface S1 of the covering 16 can be made about 16 wt %. In this case, the light absorption characteristics in the absorption region 16AB and the light scattering characteristics in the scattering reflection region 16SC in the vicinity of the surface S1 can be maintained, and resin cracking of the cover 16 can be prevented.

Also, in this embodiment, the coating 16 has a thermosetting epoxy resin or silicone resin having a refractive index within the range of 1.4 to 1.55 as the resin medium. Also, the particle group 16PT 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 the scattering of light within the coating 16, the particle group 16PT (particularly the second titanium oxide particles P2) preferably has a higher refractive index than the resin medium.

In addition, the particle size (average particle size) of each of the first to third titanium oxide particles P1 to P3 in the particle group 16PT of the covering 16 is such that good diffusion is achieved in the visible light range (for example, the range of 380 to 780 nm). Considering obtaining a reflection, it is preferably in the range of 150 to 350 nm. Further, the average particle size of the first to third titanium oxide particles P1 to P3 is 1 to 1/1 to the wavelength of light (visible light) entering the coating 16 (for example, the wavelength in the medium of the silicone resin). By setting it within the range of about 4, Mie scattering with a high backscattering ratio can be generated, and extremely good diffuse reflection can be obtained.

For example, if the resin medium has a refractive index of 1.5, light with a wavelength of 380 nm in air will have a wavelength of 253 nm in the resin medium, and light with a wavelength of 780 nm in air will have a wavelength of 520 nm in the resin medium. In this case, the titanium oxide particles P1 to P3, for example, have an average particle diameter within the range of 195 nm to 253 nm, for example, so that good diffuse reflection is achieved. Similarly, in the case of light with a wavelength of 420 nm to 680 nm in air, the titanium oxide particles P1 to P3 exhibit good diffuse reflection when the particle size is within the range of 170 nm to 280 nm.

By adjusting the average particle diameter of the particles in the particle group 16PT in consideration of these factors, the reflectance in the scattering reflection region 16SC can be increased. Also in the absorption region 16AB, the light is scattered and absorbed by the particles with a high probability, so that the absorptivity can be increased.

Further, the concentration of the particle groups 16PT in the coating 16 is preferably in the range of 5 to 70 wt% in consideration of obtaining the desired light reflectivity and light absorption, and ease of manufacture (particle-containing resin Considering the ease of application of 16P) and manufacturing costs, it is more preferable to be in the range of 8 to 30 wt%. The configuration of the particle groups 16PT and the medium in the coating 16 is merely an example.

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). film), in the irradiation step (step 7) of the laser light LB during the manufacture of the light emitting device 10, a high output laser with a wavelength of 355 nm is used to effectively and stably form each of the titanium oxides P10 to P30. Oxygen-deficient portion P00 can be generated on the surface of . Therefore, the absorption region 16AB can be stably formed only in a thin region of several μm to 20 μm from the surface S1 of the cover 16. FIG.

Further, when the particle size of the titanium oxide particles P0 is substantially equal to the wavelength of the laser beam LB within the particle-containing resin 16P, in the region within the particle-containing resin 16P, the titanium oxide particles P0 have a large backscatter ratio. Scattering occurs. As a result, the laser beam LB is scattered and reflected in the vicinity of the surface S1 of the particle-containing resin 16P. As a result, it is possible to uniformly irradiate only the vicinity of the surface S1 of the cover 16 (thin region of several μm to 20 μm from the surface S1) with the laser beam LB, and stably form the absorption region 16AB.

In addition, by using light having a wavelength with energy higher than the bandgap energy of the titanium oxide particles P0 in the particle-containing resin 16P as the laser light LB, the laser light LB can be absorbed by the titanium oxide particles P0. Therefore, irradiation of the laser beam LB to a position distant from the surface S1 of the covering 16 is suppressed. Therefore, the absorption region 16AB can be stably formed only in the vicinity of the surface S1 of the cover 16. FIG.

5A 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 bonding member 13A. In this modified example, the bonding member 13A partially covers the side surface of the light emitting element 12 . That is, the bonding member 13A is formed on the upper surface and side surfaces of the light emitting element 12. As shown in FIG. In this modification, the cover 16 is in contact with the light emitting element 12 in the lower area of the side surface of the light emitting element 12, and covers the light emitting element 12 in the upper area via the bonding member 13A.

In the light emitting device 10A, the cover 16 has a portion above the side surface of the light emitting element 12 that does not come into contact with the side surface of the light emitting element 12 . When the cover 16 is configured in this manner, the light emitted from the side surface of the light emitting element 12 can be guided by the bonding member 13A and made incident on the outer edge portion of the translucent member 14 . Therefore, the amount of light extracted from the outer edge of the translucent member 14 can be increased. Therefore, the light emitting device 10A has high contrast and low crosstalk.

5B is a cross-sectional view of a light-emitting device 10A according to Modification 2 of Embodiment 1. FIG. The light emitting device 10B has the same configuration as the light emitting devices 10 and 10A except for the configuration of the bonding member 13B. In this modified example, the bonding member 13B covers the entire side surface of the light emitting element 12 . That is, the bonding member 13B is in contact with the entire top surface and side surfaces of the light emitting element 12 . In this modification, the cover 16 covers the side surface of the light emitting element 12 via the bonding member 13B.

In the light emitting device 10B, the cover 16 does not come into contact with the side surface of the light emitting element 12 completely. When the cover 16 is configured in this manner, almost all of the light emitted from the side surface of the light emitting element 12 can enter the outer edge of the translucent member 14 by the bonding member 13B. Therefore, the amount of light extracted from the outer edge of the translucent member 14 can be increased. Therefore, the light emitting device 10B has high contrast and low crosstalk.

5C is a cross-sectional view of a light-emitting device 10C according to Modification 3 of Example 1. FIG. 10 C of light-emitting devices have the same structure as the light-emitting device 10 except for the structure of 13 C of joining members, and 14 A of translucent members. In this modified example, the translucent member 14A has an upper surface that is larger than the upper surface of the light emitting element 12 . Also, the joining member 13C is formed from the side surface of the light emitting element 12 to the bottom surface of the translucent member 14A.

In this modification, the light emitted from the light emitting element 12 is incident on the entire bottom surface of the translucent member 14A via the bonding member 13C, and then extracted to the outside from the upper surface of the translucent member 14A. Moreover, the covering 16 covers the side surface of the joining member 13C and the side surface of the translucent member 14A. Therefore, for example, the light emitted from the side surface of the light emitting element 12 can be made incident on the outer edge portion of the translucent member 14A by the bonding member 13C. Therefore, for example, it is possible to increase the size of the light extraction surface without changing the size of the light emitting element 12, and to provide the light emitting device 10C in which crosstalk is suppressed.

5D is a cross-sectional view of a light-emitting device 10D according to Modification 4 of Example 1. FIG. The light-emitting device 10D has the same configuration as the light-emitting device 10 except for the configurations of the bonding member 13D and the translucent member 14B. In this modified example, the translucent member 14B has an upper surface that is smaller than the upper surface of the light emitting element 12 . Also, the bonding member 13D is formed from the upper surface of the light emitting element 12 to the side surface of the translucent member 14B.

In this modification, the light emitted from the light emitting element 12 is incident on the bottom and side surfaces of the translucent member 14B through the bonding member 13D, and then extracted to the outside from the upper surface of the translucent member 14B. In addition, the cover 16 covers the side surfaces of the light emitting element 12 and the bonding member 13D, and the upper portion of the side surface of the translucent member 14B. Therefore, for example, the size of the light extraction surface can be reduced without changing the size of the light emitting element 12, and the light emitting device 10D with high output and low crosstalk can be provided.

5E is a cross-sectional view of a light-emitting device 10E according to Modification 5 of Example 1. FIG. The light-emitting device 10E has the same configuration as the light-emitting device 10 except that it does not have the translucent member 14 . The light emitting device 10</b>E has a substrate 11 , a plurality of light emitting elements 12 arranged side by side on the substrate 11 , and a covering 16 covering the side surfaces of the light emitting elements 12 .

The cover 17 has the same configuration as the cover 16 except that it covers the side surface of the light emitting element 12 . The covering 17 is arranged on the substrate 11 between the adjacent light emitting elements 12 and covers the side surfaces of the light emitting elements 12 . As with the coating 16, the coating 17 includes a plurality of titanium oxide particles (for example, It has a particle group 16PT containing first to third titanium oxide particles P1 to P3).

In this modified example, the upper surface of the light emitting element 12 is exposed to the outside. In this case, the emitted light from the light emitting element 12 is directly taken out without passing through another medium. Also in the light-emitting device 10E, the coating 17 includes the particle group 16PT, so that the crosstalk is suppressed.

In this embodiment, the case where the cover 16 has the absorption region 16AB that absorbs visible light and the scattering reflection region 16SC that reflects visible light has been described. However, the configuration of the cover 16 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 16AB and the scattering reflection region 16SC of the coating 16 absorb and reflect light in the other wavelength band and/or light converted to another wavelength by the wavelength converter, respectively. It's fine if you have it.

In other words, for example, it has a region having light absorbability and light reflectivity corresponding to the wavelengths of emitted light from the light emitting element 12 and emitted light from the wavelength converter included in the bonding member 13 or the translucent member 14. It is sufficient that the particles in the coating 16, their bandgap configurations, and the medium are adjusted as described above.

Also, in this case, considering that the absorption region 16AB and the scattering reflection region 16SC are effectively provided in the coating 16, for example, the titanium oxide particles in the particle group 16PT are the emitted light from the light emitting element 12 and/or bonding It is preferable that the particles have an average particle diameter corresponding to the wavelength in the coating 16 of the emitted light from the wavelength conversion body included in the member 13 or the translucent member 14 .

In addition, in consideration of maintaining mechanical strength, the coating 16 preferably has an integrally formed resin medium (for example, silicone resin) in which the plurality of titanium oxide particles of the particle group 16PT are dispersed. .

Further, in this embodiment, the case where the particle group 16PT includes the first to third titanium oxide particles P1 to P3 has been described, but the configuration of the particle group 16PT is not limited to this. For example, the particle group 16PT 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 16A near the surface S1 of the covering 16 in the covering 16 is It is sufficient if the average density of the oxygen vacancies P00 in the second titanium oxide particles P2 dispersed in the second region 16B on the substrate 11 side of the first region 16A is higher than the average density.

In addition, for example, the coating 16 is arranged at a position closest to the surface S1 and has a plurality of high-density portions (oxygen-deficient portions P00) having a bandgap smaller than the energy of the light emitted from the light-emitting element 12. 1 titanium oxide particles P1 and a portion (oxygen-deficient portion P00) arranged closer to the substrate 11 than the first titanium oxide particles P1 and having a bandgap smaller than the energy of the light emitted from the light-emitting element 12 (oxygen-deficient portion P00). and a plurality of second titanium oxide particles P2.

Also, for example, the particle group 16PT may contain at least the first titanium oxide particles P1. That is, the first titanium oxide particles P1 dispersed in the vicinity of the surface S1 of the coating 16 in the particle group 16PT should have the oxygen-deficient portion P00.

In addition, the particles forming the absorption region 16AB and the scattering reflection region 16SC in the particle group 16PT 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. In addition, zinc oxide has a property of absorbing ultraviolet rays (for example, laser light LB) having 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 vacancies to reduce the bandgap (a portion corresponding to the small bandgap portion P00 is formed).

Therefore, the particle group 16PT, 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 first to third titanium oxide particles P1 to P3, or in addition to the first to third titanium oxide particles P1 to P3. It may be contained in the particle group 16PT.

In addition to the titanium oxide particles or zinc oxide particles, the particle group 16PT also scatters emitted light from the light emitting element 12 and/or emitted light from the wavelength converter included in the bonding member 13 or the translucent member 14. Particles may be added. The particles include metal carbides such as silicon carbide (SiC), silicon nitride (Si2N3), gallium nitride (GaN), aluminum nitride (AlN), aluminum oxide (Al2O3), metal oxides, metal nitrides and the like. particles.

In other words, the coating 16 should have at least the particle group 16PT including a plurality of light-scattering metal oxide particles dispersed within the coating 16 . For example, when the particle group 16PT contains a plurality of particles including particles other than titanium oxide particles and zinc oxide particles, the plurality of particles are dispersed in the coating 16 at a uniform density, or It is sufficient if they are dispersed so that the density gradually increases toward the substrate 11 . Also, for example, all the particles included in the particle group 16PT may be dispersed at the above concentration.

Moreover, in the present embodiment, the case where the absorption region 16AB is provided in the entire region near the surface S1 of the cover 16 has been described. However, the absorbent region 16AB may be provided only in part of the region near the surface S1 of the cover 16. FIG. For example, when output is prioritized over output and crosstalk suppression, the cover 16 may have the absorption region 16AB only in a part of the region near the surface S1.

Moreover, in the present embodiment, the case where the cover 16 is provided so as to fill the inside of the frame 15 and cover the entire side surface of the translucent member 14 has been described. However, the cover 16 only needs to cover the side surfaces of the light-transmitting members 14 at least between the adjacent light-transmitting members 14 (or between the light-emitting elements 12). That is, the cover 16 and the absorption region 16AB may not be provided on the side surface of the light-transmitting member 14 that is not adjacent to another light-transmitting member 14 .

In addition, for example, when it is required to clarify the brightness of the outer edge of the region of light irradiated by the light emitting device 10, the cover 16 covers all the side surfaces of the translucent member 14 as in the present embodiment, It preferably has an absorbent region 16AB on its surface S1.

Thus, for example, the light-emitting device 10 includes a substrate 11, a plurality of light-emitting elements 12 arranged side by side on the substrate 11, a plurality of translucent members 14 each arranged on each of the light-emitting elements 12, the substrate a covering 16 disposed in a region between adjacent light-transmitting members 14 on 11 and covering each side surface of the light-transmitting members 14 .

Moreover, the coating 16 has a particle group 16PT including a plurality of light-scattering metal oxide particles dispersed within the coating 16 . Moreover, the metal oxide particles (for example, the first titanium oxide particles P1) dispersed in the vicinity of the surface S1 of the coating 16 in the particle group 16PT have oxygen-deficient portions P00. Therefore, it is possible to provide the light emitting device 10 that has a simple configuration and suppresses light crosstalk between the light emitting regions.

Further, for example, the light-emitting device 10E is arranged in a substrate 11, a plurality of light-emitting elements 12 arranged side by side on the substrate 11, and regions between the adjacent light-emitting elements 12 on the substrate 11. and a covering 17 having a surface S1 exposed to the outside. Further, the coating 17 has a particle group 16PT containing a plurality of light-scattering metal oxide particles dispersed within the coating 17 . Moreover, the metal oxide particles (for example, the first titanium oxide particles P1) dispersed in the vicinity of the surface S1 of the coating 16 in the particle group 16PT have oxygen-deficient portions P00. Therefore, it is possible to provide the light-emitting device 10E that has a simple configuration and suppresses light crosstalk between the light-emitting regions.

Further, for example, the oxygen-deficient portion P00 is a portion in which oxygen is deficient in the metal oxide particles due to irradiation with the laser beam LB. That is, the covering 16 or 17 has a region where the surface S1 of the covering 16 or 17 is irradiated with the laser beam LB. This makes it possible to form contrast-enhancing absorption regions 16AB or 17AB on the surface S1 of the covering 16 or 17 . Therefore, it is possible to provide the light-emitting device 10 which can be easily manufactured and which has a simple configuration and suppresses light crosstalk between the light-emitting regions.

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 the two-layered cover 21 is provided between the light-emitting elements 12 . The covering 21 is arranged on the substrate 11 in a region between the adjacent light emitting elements 12, and is arranged on the first covering layer 22 to cover the lower sides of the light emitting elements 12, and is arranged on the first covering layer 22 to be transparent. and a second coating layer 23 covering the side surface of the optical member 14 and having a surface S1 exposed to the outside.

In this embodiment, the second coating layer 22 is arranged on the substrate 11 in the region between the adjacent translucent members 14 so as to embed the first coating layer 21 .

In this embodiment, the first coating layer 22 covers the side surface of the support substrate 12A in the light emitting element 12. As shown in FIG. The first coating layer 22 has an absorption region 22AB (for example, first titanium oxide particles P1) near the interface with the second coating layer 23 . Further, the first coating layer 22 has a scattering reflection region 22SC (for example, second titanium oxide particles P2) closer to the substrate 11 than the absorption region 22AB.

Further, in this embodiment, the second covering layer 23 covers the side surface of the semiconductor layer 12B of the light emitting element 12 and the side surface of the translucent member 14 . The second coating layer 23 also has an absorption region 23AB (for example, the first titanium oxide particles P1) near the surface S1. Moreover, the second coating layer 23 has a scattering reflection region 23SC (for example, second titanium oxide particles P2) in a region closer to the first coating layer 22 than the absorption region 23AB.

The coating 21 can be formed, for example, by reducing the amount of the particle-containing resin 16P each time and repeating steps 4 to 7 twice. Therefore, the cover 21 can be easily formed by repeating the process of forming the cover 16 . That is, the covering 21 has a structure corresponding to the case where the covering 16 is laminated in two layers.

In this embodiment, each of the side surface of the semiconductor layer 12B, the side surface of the bonding member 13, and the side surface of the translucent member 14 serves as a surface from which light emitted from the semiconductor layer 12B can be emitted. In this embodiment, the absorption area 23AB of the second cover 23 is above the surface from which light can be emitted (light extraction surface side), and the absorption region 23AB of the first cover 22 is below the surface (on the substrate 11 side). It is surrounded by area 22AB.

Therefore, in this embodiment, the region where light crosstalk between the light emitting regions can occur is limited to the region between the absorbing regions 22AB and 23AB. A scattering reflection region 23SC of the second covering 23 is provided between the absorption regions 22AB and 23AB. Therefore, in this embodiment, it is possible to suppress the decrease in the output while suppressing the crosstalk of light. Moreover, in this embodiment, the light emitting elements 12 can be arranged closer than when the absorption region 23AB is provided only on the surface S1. Therefore, the size of the device can be reduced while suppressing crosstalk.

In addition, in the present embodiment, the case where the cover 21 has the first and second cover layers 22 and 23 having the same configuration has been described. However, the configuration of the cover 21 is not limited to this. For example, the first covering layer 22 may have a different configuration than the second covering layer 23 . For example, the first coating layer 22 is composed of a light absorber having particles that absorb light emitted from the light emitting element 12, such as carbon black, or titanium oxide particles or zinc oxide particles that absorb visible light. may be In this case, after forming the light absorber in layers as the first coating layer 22, the steps of forming the coating 16 (for example, steps 4 to 7) may be performed.

Thus, in this embodiment, the cover 21 is provided in the region between the adjacent light emitting elements 12 on the substrate 11, and covers the side surfaces of the support substrate 12A of the light emitting elements 12, the first covering layer 22; a second coating layer 23 provided on the first coating layer 22 and having a surface S1. Further, the first coating layer 22 absorbs light emitted from the light emitting element 12 at the interface with the second coating layer 23 . Therefore, it is possible to provide the light emitting device 20 that has a simple configuration and suppresses light crosstalk between the light emitting regions.

FIG. 7A is a cross-sectional view of a light emitting device 30 according to Example 3. FIG. 7B is a top view of the light emitting device 30. FIG. The light-emitting device 30 has the same configuration as the light-emitting device 10 except for the configuration of the covering 31 .

In this embodiment, the cover 31 has a plurality of recesses 31R on the surface S1. Further, in this embodiment, as shown in FIG. 7B, each of the recesses 31R of the cover 31 extends in the surface S1 of the cover 31 in a groove shape. Moreover, although not shown, each of the recesses 31R has a scaly inner wall.

The coating 31 can be formed, for example, by irradiating the upper surface S0 of the particle-containing resin 16P with laser light LB (for example, light with a wavelength in the ultraviolet region) multiple times. Specifically, a laser beam LB having a wavelength of 355 nm and an output of 25 kW/cm ² or more is irradiated in a specific pattern, and by irradiating again in the same pattern, the silicone resin is sequentially sublimated and removed from the surface of the particles. An irradiation mark of the laser beam LB remains on the upper surface S0 of the contained resin 16P. As a result, grooves corresponding to the beam diameter of the laser beam LB and its movement direction are formed on the surface S1 of the particle-containing resin 16P. This laser mark becomes the concave portion 31R of the cover 31. As shown in FIG.

The concave portion 31R of the cover 31 can be formed not only by irradiating the laser beam LB multiple times, but also by adjusting the output of the laser beam LB, the scanning speed, and the like. Also, the shape of the recess 31R is not limited to the illustrated shape. For example, the surface S1 of the cover 31 may be formed with convex portions, or may be formed with continuous wave-like unevenness. The covering 31 may have a surface S1 having various irregularities.

Also in this embodiment, each of the coatings 31 is a particle group containing a plurality of light-scattering metal oxide particles (for example, titanium oxide particles) dispersed in the coating 21, similar to the coating 16. It has 16PT. Moreover, the metal oxide particles (for example, the first titanium oxide particles P1) dispersed in the vicinity of the surface S1 of the coating 31 in the particle group 16PT have oxygen-deficient portions P00.

In the present embodiment, each surface S1 of the cover 31 has unevenness that is repeatedly provided, so that the area of the surface exposed to the outside is increased compared to, for example, a flat surface. This increases the surface area of the absorbent region 31AB provided on the covering 31 . Therefore, the cover 31 highly efficiently absorbs light entering the cover 31 from the side surface of the translucent member 14 . Therefore, crosstalk of light is suppressed with high efficiency.

In addition, in this embodiment, the case where the concave portion 31R is formed on the entire surface S1 of the cover 31 has been described. However, the recess 31R may be formed only on a part of the surface S1 of the cover 31. FIG. Also, the shape of the recess 31R is not limited to that shown in FIGS. 7A and 7B.

Thus, in the light-emitting device 30, the cover 31 has unevenness on the surface S1. Therefore, it is possible to provide the light emitting device 30 that has a simple configuration and suppresses light crosstalk between the light emitting regions.

10, 10A, 10B, 10C, 10C, 10D, 10E, 20, 30 Light-emitting device 11 Substrate 12 Light-emitting element 14 Translucent member 16, 17, 21, 31 Coating P1, P2, P3 Titanium oxide particles 16PT, 17PT Particle group

Claims (15)

a substrate;
a plurality of light emitting elements arranged side by side on the substrate;
a plurality of translucent members each arranged on each of the plurality of light emitting elements;
a cover disposed in a region between adjacent light-transmitting members of the plurality of light-transmitting members on the substrate and covering side surfaces of the plurality of light-transmitting members;
the coating has a particle group including a plurality of light-scattering metal oxide particles dispersed within the coating;
The plurality of metal oxide particles have a property that the bandgap is lowered due to oxygen deficiency,
A light-emitting device according to claim 1, wherein the plurality of metal oxide particles dispersed near the surface of the coating in the particle group has a portion with a smaller bandgap than other portions in each particle . 2. The light-emitting device according to claim 1, wherein the covering has one resin matrix that supports the plurality of metal oxide particles. 3. The light-emitting device according to claim 1, wherein the plurality of metal oxide particles are dispersed with a uniform density within the coating. 3. The light-emitting device according to claim 1, wherein the plurality of metal oxide particles are dispersed in the coating such that the density increases gradually from the surface toward the substrate. The average density of the portion of the plurality of metal oxide particles dispersed in the first region in the vicinity of the surface of the coating in the coating and having a smaller bandgap than the other portions of the coating is the 3. The average density of a portion of the plurality of metal oxide particles dispersed in a second region closer to the substrate than the first region, the bandgap of which is smaller than that of the other portion, is higher than the average density of the portion. 5. The light-emitting device according to any one of 1 to 4. The resin matrix supporting the plurality of metal oxide particles in the first region of the coating and the resin matrix supporting the plurality of metal oxide particles in the second region of the coating are continuous. 6. The light-emitting device according to claim 5, wherein the light-emitting device is formed by 7. The light emitting device according to any one of claims 1 to 6 , wherein the plurality of metal oxide particles comprise titanium oxide particles or zinc oxide particles. The light-emitting device according to any one of claims 1 to 7 , wherein the plurality of metal oxide particles are dispersed in the coating within a range of 5 to 70 wt%. 9. The light emission according to any one of claims 1 to 8 , wherein the particle group comprises the plurality of metal oxide particles and a coating film that coats the plurality of metal oxide particles. Device. The plurality of metal oxide particles having a portion with a bandgap smaller than that of the other portion are dispersed in a region within a depth range of 20 μm or less from the surface of the coating. Item 8. The light-emitting device according to Item 7 . The light emitting device according to any one of claims 1 to 10 , wherein the covering has a plurality of unevenness on the surface. each of the plurality of light emitting elements has a supporting substrate arranged on the substrate, and a semiconductor layer arranged on the supporting substrate and including a light emitting layer;
The covering includes: a first covering layer arranged in a region between adjacent light emitting elements of the plurality of light emitting elements on the substrate and covering a side surface of the supporting substrate of each of the plurality of light emitting elements; a second coating layer disposed on the first coating layer and having the surface;
2. The light-emitting device according to claim 1, wherein said first coating layer absorbs emitted light from said plurality of light-emitting elements in the vicinity of an interface with said second coating layer. . a substrate;
a plurality of light emitting elements arranged side by side on the substrate;
a covering disposed in a region between adjacent light emitting elements of the plurality of light emitting elements on the substrate and covering a side surface of each of the plurality of light emitting elements;
The coating has a particle group containing a plurality of light-scattering metal oxide particles,
at least some of the plurality of metal oxide particles have a property of lowering the bandgap due to oxygen deficiency,
A light-emitting device according to claim 1, wherein the plurality of metal oxide particles dispersed near the surface of the coating in the particle group has a portion with a smaller bandgap than other portions in each particle . 14. The light-emitting device according to any one of claims 1 to 13, wherein the proportion of the portion having a bandgap smaller than that of the other portion in each particle increases toward the vicinity of the surface of the covering. a substrate;
a plurality of light emitting elements arranged side by side on the substrate;
a covering disposed in a region between adjacent light emitting elements of the plurality of light emitting elements on the substrate and covering a side surface of each of the plurality of light emitting elements;
The coating has a particle group containing a plurality of light-scattering metal oxide particles,
at least some of the plurality of metal oxide particles have a property of lowering the bandgap due to oxygen deficiency,
The light-emitting device according to claim 1, wherein the coating has a region on the surface thereof which is irradiated with a laser beam so as to cause oxygen deficiency in the plurality of metal oxide particles .

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