JP2022145973A - Semiconductor light-emitting device - Google Patents

Abstract

To provide a flexible semiconductor light-emitting device.SOLUTION: A semiconductor light-emitting device 1 according to an embodiment includes a projection lens 10, and at least one light emitting diode sheet 30. A light-emitting portion of the light-emitting diode sheet is arranged beyond the object-side focal length of the projection lens 10. The light-emitting diode sheet 30 includes at least a plurality of light-emitting elements in which first wiring, a light-emitting layer containing a diode, and second wiring are stacked in order, and an insulating layer disposed between the plurality of light-emitting elements. The light emitting layer is in direct contact with the first wiring, and the surface of the light emitting layer opposite to the surface in direct contact with the first wiring is in direct contact with the second wiring.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to semiconductor light emitting devices.

Light-emitting devices with light-emitting diodes have been proposed. In such a light emitting device, a plurality of light emitting diodes are mounted on a substrate. Therefore, it has been difficult to provide a flexible light-emitting device.

JP 2015-112969 A

A problem to be solved by the present invention is to provide a flexible semiconductor light emitting device.

A semiconductor light emitting device according to an embodiment includes a projection lens and at least one light emitting diode sheet. The light-emitting portion of the light-emitting diode sheet is arranged beyond the object-side focal length of the projection lens. The light-emitting diode sheet includes at least a first wiring, a light-emitting layer containing a diode, a plurality of light-emitting elements in which the second wiring is stacked in order, and an insulating layer disposed between the plurality of light-emitting elements. there is The light emitting layer is in direct contact with the first wiring, and the surface of the light emitting layer opposite to the surface in direct contact with the first wiring is in direct contact with the second wiring.

1A and 1B are schematic diagrams of a semiconductor light-emitting device according to an embodiment; The model perspective view of an LED sheet. The schematic cross section of an LED sheet. The schematic cross section of the light emission part which concerns on a modification. The schematic cross section of the light emission part which concerns on a modification. 4A to 4C are process diagrams of the phosphor sheet according to the present embodiment; 4A to 4C are process diagrams of the phosphor sheet according to the present embodiment; 4A to 4C are process diagrams of the phosphor sheet according to the present embodiment; 4A to 4C are process diagrams of the phosphor sheet according to the present embodiment; 4A to 4C are process diagrams of the phosphor sheet according to the present embodiment; The schematic cross section of the LED sheet which concerns on a modification. Schematic diagrams illustrating projection principles. 4A and 4B are schematic diagrams illustrating an image forming relationship; Schematic diagram of a light source with two different positions in the depth direction. FIG. 10 is a schematic diagram of changing the illumination area according to another embodiment; FIG. 10 is a schematic diagram of changing the illumination area according to another embodiment; FIG. 10 is a schematic diagram of changing the illumination area according to another embodiment; 1A and 1B are schematic diagrams illustrating a semiconductor light-emitting device that is a lighting device; (a), (b) is a schematic diagram of a light emission part. Image diagram of light distribution. (a), (b) is a schematic diagram of the light distribution state of illumination light. (a) and (b) are schematic diagrams of a high beam area. (a) and (b) are schematic diagrams of a low beam region. (a), (b), and (c) are schematic diagrams of other high beam light sources. (a), (b) is a schematic diagram of arrangement|positioning of a light source. (a), (b) is a schematic diagram of arrangement|positioning of a light source. Schematic perspective view of a light source. (a), (b) is a schematic diagram of an illumination area. (a), (b) is a schematic diagram of an illumination area.

Hereinafter, embodiments will be illustrated with reference to the drawings. In addition, in each drawing, the same reference numerals are given to the same constituent elements, and detailed description thereof will be omitted as appropriate.
FIG. 1 is a schematic diagram for illustrating a semiconductor light emitting device 1 according to this embodiment.
As shown in FIG. 1, a semiconductor light emitting device 1 can be provided with an optical element 10 and a light emitting section 20 . The semiconductor light emitting device 1 can be, for example, a lighting device or a display device such as a projector. The details of using the semiconductor light-emitting device 1 as an illumination device (for example, an adaptive headlight) will be described later.

The optical element 10 can be provided on the light emitting side of the light emitting section 20 . The optical element 10 can be, for example, a lens. For example, the optical element 10 illustrated in FIG. 1 is a so-called plano-convex lens. However, the optical element 10 is not limited to lenses. The optical element 10 can perform, for example, at least one of collecting, diffusing, guiding, and reflecting light emitted from the light emitting section 20, and forming a predetermined light distribution pattern.

The semiconductor light emitting device 1 illustrated in FIG. 1 has one optical element 10 (for example, a so-called single lens). can also be used. It should be noted that, depending on the application of the semiconductor light emitting device 1, there are cases where the light emitted from the light emitting section 20 does not need to be collected. Therefore, the optical element 10 may be provided as required, or may be omitted.

The light emitting section 20 can have a stage 21 and a light emitting diode sheet (hereinafter referred to as an LED sheet) 30 .
The stage 21 may have, for example, a block shape. However, the form of the stage 21 is not limited to the illustrated form, and can be changed as appropriate. Further, a moving mechanism or the like for controlling the distance and position between the optical element 10 and the LED sheet 30 may be provided as appropriate.

The LED sheet 30 can be provided on the stage 21, for example. For example, the LED sheet 30 can be adhered to the stage 21 or fixed using a fastening member such as a screw.
FIG. 2 is a schematic perspective view of the LED sheet 30. FIG.
FIG. 3 is a schematic cross-sectional view of the LED sheet 30. As shown in FIG.

As shown in FIGS. 2 and 3, the LED sheet 30 includes, for example, a first wiring 31, a first buffer layer 32, a light-emitting layer 33 containing a diode, and a second wiring 34, which are laminated in order. It includes light emitting elements and an insulating layer 35 disposed between the plurality of light emitting elements. In addition, the LED sheet 30 has a first surface and a second surface opposite to the first surface, and the first wiring 31 is provided on the first surface side of the light emitting layer 33, and the light emitting layers 33 of the plurality of light emitting elements are provided. A second wiring 34 is provided on the second surface side.

In the case of the LED sheet 30 illustrated in FIG. 2, the first wirings 31 extend in the first direction and the second wirings 34 extend in the second direction.

In FIGS. 2 and 3, the light-emitting elements are of the same size and are uniformly arranged in the first direction and the second direction, but the size and arrangement of the light-emitting elements are limited to those shown in FIGS. not to be For example, when the LED sheet 30 is used as a display device, it is preferable that the light emitting elements are arranged in a specific shape and pattern.

The LED sheet 30 has a structure in which light emitting elements are arranged in an insulating layer 35 . By using a flexible polymer or the like for the insulating layer 35, the LED sheet 30 can be made flexible. “Flexible” means that the LED sheet 30 has no damage such as cracks, chipping, and disconnection after being gently wound and released 10 times around a cylindrical bar with a diameter of 200 mm under an atmospheric pressure environment of 25°C. Say.

Since the LED sheet 30 does not include a single crystal epitaxial growth substrate for growing the light-emitting layer 33 and is not used in its production, the LED sheet 30 can be produced at low cost.

The LED sheet 30 can be of a passive matrix type that does not contain drive elements (switching elements) inside. Also, the LED sheet 30 can be of an active matrix type including driving elements inside. The switching element may be one or more selected from the group consisting of inorganic TFTs (Thin Film Transistors) such as Si and IGZO, organic TFTs, CMOS and diodes, but is not particularly limited. By making the drive element flexible, the active matrix type LED sheet 30 also becomes flexible. 2 and 3 show the passive matrix type LED sheet 30. FIG.
The size of the LED sheet 30 varies from several tens of mm ² to over 1 m ² .

(first wiring)
The first wiring 31 is a conductor in direct contact with the first buffer layer 32 . The first wiring 31 is an electrode of each light emitting element. The first wiring 31 serves as one electrode of the anode or cathode of the light emitting layer 33 . The first wiring 31 is in direct contact with the first buffer layer 32 . The surface of the first buffer layer 32 in contact with the first wiring 31 is opposite to the surface of the first buffer layer 32 facing the second wiring 34 . It is preferable that the plurality of light emitting elements included in the LED sheet 30 are electrically connected via the first wiring 31 .

The first wiring 31 includes either a metal film or a transparent conductive film. The first wiring 31 can be a transparent electrode. The first wiring 31 may be a laminated film. For example, when the second wiring 34 side is the direction of light emission, a metal film may be used for the first wiring 31 so that the first wiring 31 also functions as a reflector.

In some cases, the first wiring 31 can electrically connect a plurality of light emitting elements arranged as shown in FIGS. When the LED sheet 30 is of the active matrix type, either one of the first wiring 31 and the second wiring 34 is connected to a driving element that selects a light emitting element to emit light. When the LED sheet 30 is of an active matrix type, one of the first wiring and the second wiring that is not connected to the driving element is a line-shaped, mesh-shaped, or film-shaped conductor, and a plurality of light-emitting elements. are electrically connected by a line-shaped, mesh-shaped or film-shaped conductor.
The form of the first wiring 31 includes a form of an electrode of a light emitting element, a form of a wiring connected to a drive element, a form of an electrode of a drive element, and the like.

(First buffer layer)
The first buffer layer 32 contains a layered compound. The first buffer layer 32 is preferably plate-shaped. The first buffer layer 32 is preferably a layer made of a layered compound. The first buffer layer 32 is arranged between the first wiring 31 and the light emitting layer 33 . The surface of the first buffer layer 32 facing the light emitting layer 33 is opposite to the surface of the first buffer layer 32 facing the first wiring 31 . The crystal orientation of the surface of the first buffer layer 32 facing the light-emitting layer 33 (the crystal orientation of the layered compound) is uniform. The first buffer layer 32 is a single crystal containing a plurality of two-dimensional sheet-like layered compounds. The crystallinity of the first buffer layer 32 is obtained by 4-axis X-ray diffraction measurement or transmission electron microscope observation.

In some cases, two-dimensional layered materials such as graphene, hexagonal metals such as hafnium and alloys, and ceramics can be used instead of layered compounds for growing nitride semiconductor layers.

The layered compound is in the form of a two-dimensional sheet extending in the surface direction of the first buffer layer 32 . A metal chalcogenide is preferable as the layered compound. Graphene is also a layered compound, but the lattice constant of graphene cannot be changed to match the light-emitting layer 33 . When it is a metal chalcogenide, the lattice constant of the layered compound can be controlled by the selection and ratio of the metal and chalcogen elements.

As the layered compound, a metal chalcogenide represented by MSe _α S _β Te _γ O _δ is preferable. M, which is a metal contained in the metal chalcogenide, is Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Zn, Cd, Ga, In, Ge, Sn, Pt, Au, Cu, Ag, Mn , Fe, Co, Ni, Pb and Bi. α, β and γ are 0.0≦α≦2.0, 0.0≦β≦2.0, 0.0≦γ≦2.0, 0.0≦δ≦2.0 and 1.0 It is preferable to satisfy ≦α+β+γ+δ≦2.0. Furthermore, α, β and γ are 0.0≦α≦2.0, 0.0≦β≦2.0, 0.0≦γ≦2.0, 0.0≦δ≦2.0, 0 .0<α+β+γ and 1.0≦α+β+γ+δ≦2.0 are preferably satisfied. The metal M contained in the metal chalcogenide preferably contains at least one selected from the group consisting of Mo, W and Cr. The selection and ratio of elements of the metal chalcogenide are changed according to the light emitting layer 33 to be epitaxially grown.

The diameter (D ₁ ) of the first buffer layer 32 (columnar object) is preferably in the range of 0.1 μm or more and 200 μm or less. Within this range, the size of the light source is suitable for a display device. Moreover, when the size of the light source is suitable for the lighting device, the diameter (D ₁ ) of the first buffer layer 32 (columnar object) is preferably in the range of 5 μm or more and 200 μm or less. For the diameter of the first buffer layer 32, the diameter of the inscribed circle and the diameter of the circumscribed circle of each first buffer layer 32 are obtained in a cross section perpendicular to the stacking direction of the light emitting device. The average value of the obtained inscribed circle diameter and circumscribed circle diameter is taken as the diameter of each first buffer layer. The diameter of the pillars in which the first buffer layer 32 and the light-emitting layer 33 are laminated depends on the diameter of the first buffer layer 32 . When the size of the light source is suitable for a display device, the diameter of the first buffer layer 32 (columnar object) is preferably 1 μm or more and 200 μm or less. It is preferable that the cross-sectional area and diameter of the first buffer layer 32 be changed according to the required brightness and the like. When the size of the light source is suitable for the illumination device, the diameter of the first buffer layer 32 (columnar object) is preferably 5 μm or more and 200 μm or less.

The plate shape (cross-sectional shape) of the first buffer layer 32 is often a disk shape, a polygonal prism shape such as a triangular prism shape, or a hexagonal prism shape, but any plate shape may be used. Adjacent first buffer layers 32 may have different shapes.

When the size of the light source is suitable for a mobile type, indoor display device, etc., which is viewed closely, the shortest distance (D ₂ ) between the centers of the first buffer layers 32 (pillars) of the plurality of light emitting elements is It is preferably 0.5 μm or more and 500 μm or less. When the size of the light source is suitable for a lighting device, the shortest distance (D ₂ ) between the centers of the first buffer layers 32 (pillars) of the plurality of light emitting elements is preferably 1 μm or more and 1000 μm or less. A plurality of light emitting elements are included in the LED sheet 30 . The plurality of light emitting elements are separated from each other, and there are gaps between the plurality of light emitting elements. The shortest distance between the centers of the first buffer layers 32 of the plurality of light emitting elements is obtained as follows. First, the center point of the first buffer layer 32 of one light emitting element and the center points of the first buffer layers 32 of a plurality of surrounding light emitting elements are obtained. Then, among the distances between the center point of the first buffer layer 32 of one light emitting element and the center points of the first buffer layers 32 of the plurality of light emitting elements around the periphery of the light emitting element, the shortest distance is selected from the plurality of light emitting elements. It is the shortest distance between the centers of the first buffer layer 32 . The center point of the first buffer layer 32 of the light emitting device is the center of the circumscribed circle of the first buffer layer 32 . When the size of the light source is suitable for a display device viewed from close, the shortest distance between the centers of the first buffer layers 32 (columnar objects) of the plurality of light emitting elements is 5 μm or more and 300 μm or less, or 0.5 μm or more. It is more preferably 3 μm or less. The shortest distance between the centers of the first buffer layers 32 of the plurality of light emitting elements is changed according to the number of pixels of the product and the like. When the size of the light source is suitable for a lighting device, the shortest distance between the centers of the first buffer layers 32 (pillars) of the plurality of light emitting elements is 50 μm or more and 2000 μm or less, or 300 μm or more and 2000 μm or less depending on the application. is more preferable.

The thickness of the first buffer layer 32 is not particularly limited. The thickness of the first buffer layer 32 is, for example, 10 nm or more and 30 nm or less. Variation in the thickness of the first buffer layer 32 is preferably as small as possible.

The first buffer layer 32 and the light emitting layer 33 have a heteroepitaxial relationship.
The stacking direction of the light-emitting element is parallel to the hexagonal c-axis of the metal chalcogenide. The metal chalcogenide in the direction perpendicular to the stacking direction of the light-emitting element is parallel to the hexagonal crystal system a and b axes. The orientation of the metal chalcogenide parallel to the substrate surface is random when viewed vertically from the substrate surface and is not particularly limited.

The lattice constant of the metal chalcogenide can be arbitrarily changed by selecting the element. Therefore, by changing the composition of the metal chalcogenide, the lattice constant of the epitaxially grown single crystal layer and the lattice constant of the metal chalcogenide can be matched. In other words, by changing the composition of the metal chalcogenide according to the single crystal layer to be epitaxially grown and the crystal orientation to be grown, it is possible to prepare a substrate suitable for epitaxial growth such as GaN, InN, and AlN. In these hexagonal nitrides, the plane orientation to be grown is the 0001 direction.

The difference between the in-plane lattice constant of the first buffer layer 32 and the in-plane lattice constant of the layer closest to the first buffer layer 32 among the light-emitting layers 33 in which a plurality of layers are stacked (=([of the first buffer layer 32 In-plane lattice constant]−[In-plane lattice constant of the layer closest to the first buffer layer 32 in the light-emitting layer 33]/[In-plane lattice constant of the first buffer layer 32]) is within ±1%. If the lattice constant difference is large, epitaxial growth is difficult, and if the difference is large, epitaxial growth will not occur or crystal defects will easily occur.Therefore, the in-plane lattice constant of the first buffer layer 32 and the plurality of layers The difference in the in-plane lattice constant of the layer closest to the first buffer layer 32 among the laminated light emitting layers 33 is more preferably within ±0.5%.The lattice constant is determined by 4-axis X-ray diffraction Alternatively, it is roughly determined by the composition ratio of the metal chalcogenide that constitutes the first buffer layer 32. For example, for the growth of an epitaxial GaN wafer with a plane orientation of (0001), MoS1.6Se0 is added to the metal chalcogenide. Then, the error between the a-axis length of GaN of 3.189 Å and the a-axis length of metal chalcogenide of 3.189 Å is 0.0%, which is suitable for epitaxial growth of GaN.

The two-dimensional sheet-like metal chalcogenide in direct contact with the light-emitting layer 33 of the first buffer layer 32 may be composed of a plurality of two-dimensional sheet-like metal chalcogenides. At this time, on the surface of the first buffer layer 32 that is in direct contact with the light-emitting layer 33 , the plurality of two-dimensional sheet-like metal chalcogenides are arranged so that their crystal orientations are aligned. A plurality of two-dimensional sheet-shaped metal chalcogenides may overlap each other without any problem, and may have steps. Even if the surface of the first buffer layer 32 that is in direct contact with the light-emitting layer 33 is not a single two-dimensional sheet of metal chalcogenide when it is separated from the substrate used for fabrication, a plurality of two-dimensional sheets may be used. Epitaxial growth of the light-emitting layer 33 on the first buffer layer 32 is possible if the crystal orientation of the metal chalcogenide is uniform. Since epitaxial growth is possible even if it is not a perfect sheet, a member having a plurality of first buffer layers 32 arranged on a substrate can be produced at low cost. By using the substrate to manufacture the LED sheet 30, the manufacturing cost of the LED sheet 30 can be suppressed.

(Light emitting layer)
The light emitting layer 33 is a light emitting diode arranged between the first buffer layer 32 and the second wiring 34 . The light emitting layer 33 is in direct contact with the first buffer layer 32 and in direct contact with the second wiring 34 . The surface of the light-emitting layer 33 in direct contact with the second wiring 34 is opposite to the surface in direct contact with the first buffer layer 32 .

The light emitting layer 33 includes a first conductivity type semiconductor layer (compound semiconductor layer), an active layer, and a second conductivity type semiconductor layer (compound semiconductor layer). The light emitting layer 33 includes a hexagonal nitride semiconductor layer. It is preferable that the light-emitting layer 33 is formed by laminating a plurality of hexagonal nitride semiconductor layers. The multiple layers of light emitting layer 33 are preferably in a heteroepitaxial relationship. In other words, it includes a quantum well structure that improves luminous efficiency. The nitride semiconductor layer is preferably a single crystal layer of GaN, InN, AlN, and a mixed composition of two or more selected from the group consisting of GaN, InN and AlN. The in-plane lattice constant of the nitride semiconductor layer varies from 3.111 Å to 3.532 Å depending on these mixed composition ratios. The composition ratio of the metal chalcogenide may be changed slightly in consideration of the difference in thermal expansion coefficients and the growth rate during film formation.

Compound semiconductors (including an active layer) used for the light emitting layer 33 include GaN, InN, AlN, and mixed compositions of two or more selected from the group consisting of GaN, InN, and AlN, as well as GaAs and the like. Phosphorus-based compound semiconductors such as arsenic-based compound semiconductors and InGaAlP can be used. An arsenic-based compound semiconductor and a phosphorus-based compound semiconductor can also match the in-plane lattice constant with the first buffer layer 32 in the same manner as the nitride semiconductor. An arsenic-based compound semiconductor or a phosphorus-based compound semiconductor can suitably grow from the first buffer layer 32 as the light-emitting layer 33 . That is, the semiconductor layer of the first conductivity type, the active layer, and the semiconductor layer of the second conductivity type are semiconductor layers containing one or more selected from the group consisting of nitride semiconductors, arsenic-based compound semiconductors, and phosphorus-based compound semiconductors. .

When the light-emitting layer 33 is a blue light-emitting diode, the light-emitting layer 33 is a laminate of, for example, first conductivity type GaN, first conductivity type AlGaN, InGaN, second conductivity type AlGaN, and second conductivity type GaN. It has a structure that In this case, the in-plane lattice constant of the first buffer layer 32 is matched to GaN. As described above, by using MoS _1.6 Se _0.4 as the metal chalcogenide, the lattice constants of the metal chalcogenide and GaN are matched.

The diameter (D ₃ ) of the light-emitting layer 33 (columnar object) is preferably in the range of 0.1 μm or more and 200 μm or less. Within this range, the size of the light source is suitable for a display device. When the size of the light source is suitable for a lighting device, the diameter (D ₃ ) of the light emitting layer 33 (columnar object) is preferably in the range of 50 μm or more and 3000 μm or less. For the diameter of the light emitting layer 33, the diameter of the inscribed circle and the diameter of the circumscribed circle of the light emitting layer 33 are obtained in a cross section perpendicular to the stacking direction of the light emitting element. The average value of the obtained inscribed circle diameter and circumscribed circle diameter is taken as the diameter of each light emitting layer 33 . The diameter of the pillars in which the first buffer layer 32 and the light-emitting layer 33 are laminated is affected by the diameter of the first buffer layer 32 . When the size of the light source is suitable for a display device, the diameter of the light emitting layer 33 (columnar object) is preferably 1 μm or more and 200 μm or less. The cross-sectional area and diameter of the light-emitting layer 33 are preferably changed according to the required luminance and the like. For example, when the size of the light source is suitable for a lighting device, the diameter of the light emitting layer 33 (columnar object) is preferably 50 μm or more and 3000 μm or less.

The cross-sectional shape of the light-emitting layer 33 is often a disk shape, a polygonal prism shape such as a triangular prism shape, or a hexagonal prism shape, but is not particularly limited. Adjacent light-emitting layers 33 may have different shapes.

When the size of the light source is suitable for a display device, the shortest distance (D ₄ ) between the centers of the light emitting layers 33 of the plurality of light emitting elements is preferably 0.5 μm or more and 500 μm or less. When the size of the light source is suitable for a lighting device, the shortest distance (D ₄ ) between the centers of the light emitting layers 33 of the plurality of light emitting elements is preferably 1 μm or more and 1000 μm or less. A plurality of light emitting elements are included in the LED sheet 30 . The plurality of light emitting elements are separated from each other, and there are gaps between the plurality of light emitting elements. The shortest distance between the centers of the light emitting layers 33 of the plurality of light emitting elements is obtained as follows. First, the center point of the light emitting layer 33 of one light emitting element and the center points of the light emitting layers 33 of a plurality of surrounding light emitting elements are obtained. Then, among the distances between the center point of the light emitting layer 33 of one light emitting element and the center points of the light emitting layers 33 of the plurality of light emitting elements around the light emitting element, the shortest distance is the distance of the light emitting layers 33 of the plurality of light emitting elements. The shortest distance between centers. The center point of the light-emitting layer 33 of the light-emitting element is the center of the circumscribed circle of the light-emitting layer 33 . When the size of the light source is suitable for a display device, the shortest distance between the centers of the light emitting layers 33 of the plurality of light emitting elements is more preferably 5 μm or more and 300 μm or less, or 30 μm or more and 3 μm or less. The shortest distance between the centers of the light emitting layers 33 of the plurality of light emitting elements is changed according to the number of pixels of the product and the like. When the size of the light source is suitable for a lighting device, the shortest distance between the centers of the light emitting layers 33 of the plurality of light emitting elements is more preferably 50 μm to 300 μm or 300 μm to 2000 μm.

(second wiring)
The second wiring 34 is a conductor in direct contact with the light emitting layer 33 . The second wiring 34 is an electrode of each light emitting element. It is preferable that the plurality of light emitting elements included in the LED sheet 30 are electrically connected via the second wiring 34 . The second wiring 34 includes either a metal film or a transparent conductive film. The second wiring 34 can be a transparent electrode. The second wiring 34 may be a laminated film.
For example, when the first wiring 31 side is the direction of light emission, a metal film may be used for the second wiring 34 so that the second wiring 34 also functions as a reflector.

The form of the second wiring 34 includes a form of an electrode of a light emitting element, a form of a wiring connected to a drive element, a form of an electrode of a drive element, and the like.

(insulating layer)
The insulating layer 35 is arranged between the plurality of light emitting elements. The insulating layer 35 preferably holds the light emitting elements and serves as the base of the LED sheet 30 . The insulating layer 35 is made of an insulating material containing polymer. The surface of the insulating layer 35 facing the light emitting element is in direct contact with at least part of the surface of the light emitting element facing the insulating layer 35 (side surface of the light emitting element). The surface of the insulating layer 35 facing the light emitting element includes a direction perpendicular to the stacking direction of the light emitting element. The insulating layer 35 is in direct contact with the side surfaces of the first buffer layer 32 and the light emitting layer 33 or the first buffer layer 32 and the light emitting layer 33 .

The insulating layer 35 is filled between the light emitting layers 33 grown in a columnar shape and spreads like a sheet. The insulating layer 35 is a polymer spacer. The film thickness of the insulating layer 35 is such that it covers the first buffer layer 32 and the light-emitting layer 33 grown on the first buffer layer 32, specifically, it is approximately 2 μm to 5 μm. The insulating layer 35 provides insulation between the light-emitting layers 33 and is also responsible for the flexibility of the light-emitting element sheet and display sheet as products, and the material is preferably selected based on strength and workability.

A colored or colorless polymer can be used as the insulating layer 35 . From the viewpoint of reducing light absorption loss, colorless and transparent materials are more desirable. Examples of polymers that can be used as the insulating layer 35 include fluorine resin, epoxy resin, and silicone resin.

As the insulating layer 35, for example, fluorine-based resin, transparent resin, transparent polymer, or the like is filled at least between a plurality of light emitting layers including diodes. Specifically, it covers at least part of the side surface of the light emitting layer 33 and fills at least between the plurality of light emitting layers so that the plurality of light emitting layers 33 are not in direct contact with each other. More specifically, when the first wiring 31 and the second wiring 34 are also formed on part of the side surface of the light emitting layer 33 , the insulating layer 35 is also formed on the outer peripheral side surface of the first wiring 31 and the second wiring 34 . is sometimes formed. More specifically, the insulating layer 35 is formed on the surface where the light-emitting layer 33 which is the upper end surface of the light-emitting layer 33 contacts the first wiring 31 and the surface where the light-emitting layer 33 which is the lower end surface contacts the second wiring 34 . preferably not. More specifically, the insulating layer 35 may partially cover the side surfaces of the first wiring 31 and the second wiring 34 , but the surface of the first wiring 31 opposite to the surface facing the light emitting layer 33 may be covered. It is preferable that the insulating layer 35 is not formed on the surface of the second wiring 34 opposite to the surface facing the light emitting layer 33 .

The insulating layer 35 is in contact with the light emitting layer 33 . In the case of a light source suitable for a display device, the light emitted from the light emitting layer 33 is totally reflected by the surface in contact with the insulating layer 35, thereby preventing color mixture in the pixels. When the light-emitting elements 33 are closely arranged, the distance between the light-emitting elements becomes narrow, and color mixture between pixels is likely to occur. By selecting it as the layer 35, it is possible to prevent color mixture between pixels. For example, when the light-emitting layer 33 is GaN, the refractive index n3 of the light-emitting layer ₃₃ is about 3.0, specifically 2.4 to 2.5, which is similar to other nitride semiconductor layers. In detail, it is a numerical value close to about 1.9 to 2.9. Considering that the light-emitting layer 33 has a refractive index of about 2.4 to 2.5, it is preferable to select a material for the insulating layer 35 having a refractive index smaller than n3 of the light-emitting layer ₃ . Specifically, the refractive index n5 of the insulating layer 35 is less than _2.5 , preferably less than 1.9, and more preferably less than 1.5. When a fluororesin having a refractive index of about 1.3 is used as the insulating layer 35, the difference in refractive index between the insulating layer 35 and the light emitting layer 33 is very large, preventing color mixture between pixels and increasing the light emission intensity of the LED sheet 30. Very favorable in terms of heightening.

(Light emitting unit 120)
FIG. 4 is a schematic cross-sectional view of a light emitting section 120 according to a modification.
A light-emitting portion 120 shown in FIG. 4 has a configuration in which phosphor sheets 40 and 50 are further provided in the above-described light-emitting portion 20 . The phosphor sheets 40 and 50 can be provided in the direction in which the LED sheet 30 emits light. For example, as shown in FIG. 4, when the second wiring 34 side is the direction of light emission, phosphor sheets 40 and 50 can be provided on the second wiring 34 side. In addition, when the first wiring 31 side is the light emission direction, the phosphor sheets 40 and 50 can be provided on the first wiring 31 side. Also, the case where the phosphor sheet 40 is provided between the LED sheet 30 and the phosphor sheet 50 is illustrated, but the phosphor sheet 50 may be provided between the LED sheet 30 and the phosphor sheet 40. good.

The phosphor sheet 40 includes a plurality of phosphor layers 41 and a retention layer 42 arranged between the plurality of phosphor layers 41 .
The fluorescent layer 41 can be provided facing any light-emitting layer 33 . Although the diameter of the fluorescent layer 41 is not particularly limited, it can be approximately the same as the diameter of the light emitting layer 33, for example. The cross-sectional shape of the fluorescent layer 41 is often a disk shape, a polygonal prism shape such as a triangular prism shape, or a hexagonal prism shape, but is not particularly limited. Adjacent fluorescent layers 41 may have different shapes. The fluorescent layer 41 can contain, for example, a red phosphor. For example, the light-emitting layer 33 of the LED sheet 30 emits blue light B, and part of the blue light B incident on the phosphor layer 41 is converted into red light R and emitted from the phosphor layer 41 .

The retention layer 42 is arranged between the plurality of fluorescent layers 41 . The holding layer 42 preferably holds the phosphor layer 41 and serves as the base of the phosphor sheet 40 . The retention layer 42 is composed of a material containing a polymer. The surface of the retaining layer 42 facing the fluorescent layer 41 is in direct contact with at least part of the surface of the fluorescent layer 41 facing the retaining layer 42 (side surface of the fluorescent layer 41). The surface of the retention layer 42 facing the fluorescent layer 41 includes the direction perpendicular to the thickness direction of the fluorescent layer 41 .

The holding layer 42 is filled between the fluorescent layers 41 grown in a columnar shape and spreads in a sheet shape. Retention layer 42 is a polymer spacer. The holding layer 42 is a part responsible for the flexibility of the phosphor sheet 40, and the material is preferably selected based on strength and workability. In this case, the thickness of the fluorescent layer 41, which has the function of converting the wavelength of light, must be increased to some extent, but considering flexibility and the like. It is preferable to reduce the thickness of the holding layer 42 . Therefore, the thickness of the retention layer 42 can be made thinner than the thickness of the fluorescent layer 41 .

A colored or colorless polymer can be used as the retention layer 42 . From the viewpoint of reducing light absorption loss, colorless and transparent materials are more desirable. Polymers that can be used as the holding layer 42 include, for example, fluorine resins, epoxy resins, silicone resins, and the like. As the holding layer 42 , for example, fluorine-based resin, transparent resin, transparent polymer, or the like is filled at least between the plurality of fluorescent layers 41 .

The phosphor sheet 50 includes a plurality of phosphor layers 51 and a retention layer 52 arranged between the plurality of phosphor layers 51 .
The fluorescent layer 51 can be provided facing any light-emitting layer 33 at a position not facing the fluorescent layer 41 . The diameter and cross-sectional shape of the fluorescent layer 51 can be the same as the diameter and cross-sectional shape of the fluorescent layer 41 . The fluorescent layer 51 can contain, for example, a green phosphor. For example, the light-emitting layer 33 of the LED sheet 30 emits blue light B, and part of the blue light B incident on the phosphor layer 51 is converted into green light G and emitted from the phosphor layer 51 .

The retention layer 52 is arranged between the plurality of fluorescent layers 51 . The holding layer 52 preferably holds the phosphor layer 51 and serves as the base of the phosphor sheet 50 . The material and form of the retention layer 52 can be the same as those of the retention layer 42 .

If a phosphor sheet 40 for converting blue light B into red light R and a phosphor sheet 50 for converting blue light B into green light G are provided, blue light B and red light R , and green light G are mixed, the semiconductor light emitting device 1 capable of emitting white light can be obtained. Further, by controlling the proportions of blue light B, red light R, and green light G, the semiconductor light emitting device 1 can emit light of various colors. Depending on the application of the semiconductor light-emitting device 1, the phosphor sheets 40 and 50 can be omitted, or one of the phosphor sheets 40 and 50 can be provided, and the blue light B can be used to emit light other than red and green. A phosphor sheet having a phosphor layer that converts to light of any color may also be provided.

(Light emitting unit 121)
FIG. 5 is a schematic cross-sectional view of a light emitting section 121 according to a modification.
Similar to the light emitting section 120 described above, the phosphor sheets 40 and 50 can be provided in the light emitting section 121 . As mentioned above, the thickness of the retention layer 42 can be less than the thickness of the phosphor layer 41 . Also, the thickness of the retention layer 52 can be made thinner than the thickness of the fluorescent layer 51 . In this case, as shown in FIG. 5, the fluorescent layer 41 can protrude from the holding layer 42. FIG. The fluorescent layer 51 can protrude from the retaining layer 52 . Then, as shown in FIG. 5, the side of the phosphor sheet 40 from which the phosphor layer 41 protrudes faces the phosphor sheet 50 side, and the side of the phosphor sheet 50 from which the phosphor layer 51 protrudes faces the phosphor sheet 40 side. By stacking the phosphor sheet 40 and the phosphor sheet 50, the dimension in the stacking direction can be reduced. That is, it is possible to reduce the thickness of the light emitting section 121 . In addition, since positional displacement between the light emitting layer 33 and the fluorescent layer 41 and positional displacement between the light emitting layer 33 and the fluorescent layer 51 can be suppressed, the light emitting section 121 can emit uniform light.

(Production of phosphor sheet)
The configuration of the phosphor sheet 50 can be the same as the configuration of the phosphor sheet 40 except that the material of the phosphor layer 51 is different from the material of the phosphor layer 41 . Therefore, a method for manufacturing the phosphor sheet 40 will be described below as an example.

FIG. 6 shows a step (first step) of forming a plurality of plate-like precursors 201 of the buffer layer 202 on the non-oriented substrate 200 . The non-oriented substrate 200 may be made of any material such as glass, metal, polycrystal, plastic (resin), ceramics, amorphous, etc., as long as there is no uniquely determined crystal orientation over the entire surface of the substrate. The non-oriented substrate 200 is not particularly limited as long as it can hold the fluorescent layer 41 when the fluorescent layer 41 is epitaxially grown. The non-oriented substrate 200 does not need to use an expensive single crystal substrate. Also, the fluorescent layer 41 does not include the non-oriented substrate 200 .

The precursor 201 can be formed, for example, by forming a metal film (or alloy film) and patterning it. Precursors 201 include Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Zn, Cd, Ga, In, Ge, Sn, Pt, Au, Cu, Ag, Mn, Fe, Co, Ni , Pb and Bi. From the viewpoint of epitaxial growth, all plate-like precursors 201 preferably have the same composition. The material of the precursor 201 can be appropriately selected according to the material of the fluorescent layer 41 to be epitaxially grown, which will be described later.

FIG. 7 shows the step of heating the non-oriented substrate 200 provided with the precursor 201 (second step). Heating is performed in an atmosphere containing at least one selected from the group consisting of Se, S, Te and O (oxygen). A buffer layer 202 is formed on the non-oriented substrate 200 by such heat treatment. The heating conditions (atmosphere, temperature, time, etc.) are selected according to the fluorescent layer 41 to be epitaxially grown. All plate-like buffer layers 202 preferably have the same composition.

FIG. 8 shows a step (third step) of epitaxially growing the phosphor layer 41 on the plurality of buffer layers 202 to form a plurality of pillars. The pillar consists of one buffer layer 202 and the fluorescent layer 41 formed on this buffer layer 202 . Since the lattice constant of the buffer layer 202 matches the lattice constant of the fluorescent layer 41 to be epitaxially grown, the fluorescent layer 41 is epitaxially grown on the buffer layer 202 . Since it is difficult to grow on the non-oriented substrate 200 , the fluorescent layer 41 grows selectively on the buffer layer 202 .

The material of the epitaxially grown phosphor layer 41 is a phosphor compound having a six-fold symmetric crystal structure, such as Ca3(PO4)2, Sr3(PO4)2, Ba3(PO4)2, ZnS, CdS/ZnS, InP/GaP/ZnS. , InP/ZnS, Si—Al—ON, YO.65GdO.35B03; E3+, Zn2SiO4; Mn2+, (Y,Gd)BO3; Tb3+, and the like.

FIG. 9 shows a step (fourth step) of forming a holding layer 42 between a plurality of pillars. The retention layer 42 is formed by filling the above-described polymer between the plurality of pillars formed on the non-oriented substrate 200 . The retention layer 42 can be formed by dipping, spraying, spin coating, or the like. As shown in FIG. 9, the holding layer 42 may be partially exposed on the side opposite to the non-oriented substrate 200 side of the pillars, or may completely cover the pillars. If desired, a portion of the retention layer 42 can be removed to expose the surface of the phosphor layer 41 in order to reduce the thickness of the retention layer 42 .

FIG. 10 shows the step of peeling off the non-oriented substrate 200 (fifth step). Since the plurality of buffer layers 202 are fixed to the non-oriented substrate 200 by Van der Waals contact, the plurality of buffer layers 202 can be physically peeled off from the non-oriented substrate 200 easily. By peeling off the plurality of buffer layers 202 and the holding layer 42 from the non-oriented substrate 200 and removing the plurality of buffer layers 202, the phosphor sheet 40 shown in the cross-sectional view of FIG. 4 is obtained. Removal of the plurality of buffer layers 202 can be performed, for example, by electrostatic adsorption, ultrasonic treatment, cleaning, etching, or the like.

(LED sheet 130)
FIG. 11 is a schematic cross-sectional view of an LED sheet 130 according to a modification.
The LED sheet 130 shown in FIG. 11 has a configuration in which a space 36 is further provided in the LED sheet 30 described above. A space 36 can be provided inside the insulating layer 35 between the light emitting layers 33 . The space 36 can extend, for example, along the direction in which the plurality of light emitting layers 33 are arranged. A plurality of spaces 36 may be connected to each other, may be connected in groups of spaces 36, or may be separated from each other.

Here, when a voltage is applied to the light emitting layer 33, light is emitted from the light emitting layer 33 and heat is generated. Therefore, the temperature of the light emitting layer 33 rises. Moreover, when the semiconductor light emitting device 1 is installed in a high temperature environment, the temperature of the light emitting layer 33 may further rise. If the temperature of the light-emitting layer 33 becomes too high, the life of the light-emitting layer 33 may be shortened or the function of the light-emitting layer 33 may be deteriorated.

Since the space 36 is provided between the light emitting layers 33 in the LED sheet 130 , the fluid can be supplied to the inside of the space 36 . Considering fluidity, the fluid is preferably a liquid such as ethylene glycol or fluorocarbon.
Further, the semiconductor light emitting device 1 may be provided with a cooling mechanism for cooling the fluid that circulates inside the LED sheet 130 and is discharged to the outside of the LED sheet 130 .
According to the present embodiment, the plurality of light emitting layers 33 can be cooled by the fluid supplied to the space 36, so temperature rise of the plurality of light emitting layers 33 can be suppressed.

Also, as will be described later, there are cases where a plurality of LED sheets 130 are stacked in the thickness direction. Therefore, the space 36 can also be shaped like a lens. In this way, the fluid supplied inside the space 36 can act as a lens for the light emitted from the lower LED sheet 130 .

The space 36 can be formed, for example, as follows. First, a material that is easier to dissolve and remove than the insulating layer 35 is linearly applied between the light emitting layers 33 . Next, an insulating layer 35 is formed between the light emitting layers 33 . The insulating layer 35 can be formed by dipping, spraying, spin coating, or the like. Next, the space 36 is formed by removing the linearly applied material.

(Lighting device)
Next, a case where the semiconductor light-emitting device according to the embodiment of the present invention is a lighting device will be described.
Here, as an example, a case where a semiconductor light emitting device is used for a headlight of an automobile will be described.
2. Description of the Related Art Conventionally, automobile headlights have functions of a high beam for illuminating distant objects and a low beam for illuminating near objects. The high beam illuminates a distance of about 100m, and is used to obtain information necessary for safe driving operation, such as road signs and other obstacles on the road ahead. . The low beam illuminates the road surface up to about 40m, and does not illuminate the area of 80cm to 120cm or more from the road surface. This area corresponds to the position of the eyes of pedestrians in front of the vehicle and the positions of the eyes of the drivers of oncoming and forward vehicles. do not impede Conventionally, these light distributions have been manually switched. When the car is driving alone at night, the high beam light is distributed so that it can be seen far away, but when a vehicle approaching from the front is detected, it is manually switched to low beam. As a result, it is possible to avoid hindering the operation of nearby vehicles.

In recent years, adaptive headlights (referred to as ADB (Adaptive Driving Beam), AHS (Adaptive Hi-beam System), AFS (Adaptive Front-Lighting System), etc.) that automatically switch between these Adaptive headlights are intended to automatically control these light distributions (in the above example, switching between high beam light distribution and low beam light distribution), but in addition to this, the left and right direction For example, a control such as switching to a wide light distribution has been proposed.

Conventional adaptive headlights basically have a set of a light source and a projection optical system adapted to a certain irradiation range. For this reason, it is necessary to have a light source and an optical system corresponding to the limited number of irradiation ranges, which generally results in a large system.

The above-described LED sheet is characterized in that the single element (light emitting element: light emitting layer 33) has high efficiency and high light emission and is small in size. Therefore, by using the LED sheet, it is possible to compactly integrate small high-intensity light-emitting elements. If an LED sheet is used as a light source, it is possible to obtain a compact light distribution control type headlight capable of splitting and distributing light over a wide area such as high beam, low beam, front, back, left, right, top and bottom. In an ideal state, a single light source and a single projection optical system can finely control the light distribution over the wide area described above.

As a light source used in the semiconductor light emitting device according to this embodiment, an LED sheet (small light emitting elements integrated on a single sheet) is used. The light-emitting elements have a diameter of about 0.1 mm, and they are integrated.
FIG. 12 is a schematic diagram illustrating the projection principle.
FIG. 13 is a schematic diagram illustrating an imaging relationship.
An imaging optical system is used in a semiconductor light emitting device. For simplicity, a single lens configuration is considered. With respect to a projection lens (single lens) having an object-side focal length f and an image-side focal length f', a light source is placed at a distance s1 from the object-side focal position. The light of height h1 on the light source hijacks the law of image formation, and forms an image of height h2 at a point s1' away from the image-side focal length f'. The imaging relationship at this time is given by equation (1), and the magnification of the image height is given by equation (2).

s1×s1′=f×f′ (1)
-f/s1=-s1'/f' (2)
According to this method, by independently turning on and off the light emitting elements integrated on the light source, it is possible to selectively turn on/off the illumination range in accordance with the enlargement ratio. For this reason, it is possible to eliminate mechanically driven light shielding devices and refraction slits that have been used to change the light distribution range in conventional headlights, which is advantageous in terms of cost. At the same time, it leads to widening the range of application in terms of design.

By using such an imaging optical system, it is possible to change the position of the light emitting element that emits light on the light source side and control the irradiation area for various spatial positions.
FIG. 14 shows the case where two light sources, s1 and s2, having different positions in the depth direction are provided. In this case, the irradiation range is limited to different depth positions corresponding to the object side positions s1 and s2. Light source A for high beam is adjusted to a position where an image can be formed at a distance, and light source B for low beam is positioned near and below. It is possible to make it last.

15, 16, and 17 are schematic diagrams illustrating changes in illumination areas according to other embodiments.
As shown in FIGS. 15, 16, and 17, by changing the light emitting point on the light source side, the illumination area can be changed to any position on the image side, front, back, left, right, up and down.

When considering illumination using imaging as in the present invention, the longer the projection distance, the greater the magnification of the light source. This produces a very magnified source image that is difficult to segment. In order to avoid this, a light source that has both a very small light source size and high emission luminance that can be used for illumination is required. The LED sheet described above is perfect for this application. In other words, such a lighting device can be realized by using the above-described LED sheet.

(Example 1)
The drawings exemplified below are schematic diagrams, and the positions of the optical axis, the focal point, and the like are greatly different from reality.
FIG. 18 is a schematic diagram illustrating a semiconductor light-emitting device 11 that is a lighting device (headlight).
A semiconductor light emitting device 11 is provided with a projection lens as an optical element 10 . The projection lens is a plano-convex lens with a focal length of 320 mm. The semiconductor light emitting device 11 is a system using a single lens.

At this time, the position of the principal point is considered to be several mm inside the lens from the plane side (herein referred to as the object side), but the light source was arranged with the position 320 mm from the object side as the reference of the focal length. The light source was placed on the stage 21 to correct the focal length position error described above.

The light emitting section 20 a has a stage 21 , a light source 22 and a light source 23 .
FIG. 19A is a schematic enlarged view (side view) of the light emitting portion 20a.
FIG. 19(b) is a schematic front view of the light emitting section 20a.
As shown in FIGS. 19A and 19B, a light source 22 and a light source 23 can be provided in the light emitting section 20a. The light source 22 has a light emitting surface at a position 1 mm away from the focal position of the optical element 10 (projection lens). The light source 23 has a light emitting surface at a position 2.5 mm away from the focal position of the optical element 10 (projection lens). The light source 22 is a light source for far projection (for high beam), and the light source 23 is a light source for near projection (for low beam). The light sources 22, 23 are both composed of segmented light emitting elements. For example, the light emitting surfaces of the light sources 22 and 23 can be divided into a plurality of square areas at intervals of 1 mm, and the above-described LED sheets 30 and 130 can be provided for each of the plurality of square areas. Note that the phosphor sheets 40 and 50 described above may be further provided.

As shown in FIGS. 19A and 19B, the high beam light source 22 is arranged with the center of the light source as the center of the optical axis. Unlike this, the low beam light source 23 is arranged so that its lower end is in contact with the center of the optical axis. By arranging the light sources centered on the optical axis, it is possible to create an irradiation area for the low beam light only in the downward direction from the optical axis, and to irradiate the entire area centered on the optical axis for the high beam light. becomes possible.

FIG. 20 is an image diagram of light distribution.
Projected light from the light source 22 placed 1 mm away from the focal length on the object side is distributed over the entire surface around the optical axis at a position about 100 m away from the emission position. The enlargement ratio at this time is about 320 times. In this embodiment, the light source 22 is given a size of 10 mm, forming an irradiation area of 3 m square in front.

The light emitting surface of the light source 23 is placed 2.5 mm away from the focal length on the object side, and this projection light forms an image at a position about 40 m away from the emission position. The image of the light source 23 arranged above the center of the optical axis illuminates the area below the center of the optical axis. Such light distribution characteristics are suitable for passing lighting of vehicles.

Next, a light distribution image within the irradiation plane will be described.
FIG. 21A is a schematic diagram (side view) of the light distribution state of illumination light in the low beam region.
FIG. 21B is a schematic diagram (side view) of the light distribution state of the illumination light in the high beam region.
Depending on the shape of the light emitting element assembly arranged in the light sources 22 and 23, divided light distribution regions corresponding to the number are generated. As shown in FIG. 21(a), a light distribution area is generated below the optical axis in the low beam area. As shown in FIG. 21(b), a light distribution area is generated over the entire surface of the high beam area.

FIG. 22(a) is a side view of the high beam area.
FIG. 22(b) is a front view of the high beam area.
As shown in FIGS. 22(a) and 22(b), it is possible to isotropically widen the light distribution area around the optical axis in the high beam area. In this example, the light emitting element set was about 1 mm×1 mm, and 10×10 pieces were integrated as a light source of 1 cm×1 cm. The aggregate of these light emitting elements is magnified approximately 320 times and projected.

In other words, it is possible to divide an area of about 30 cm×30 cm and change the illumination area (change illumination and non-illumination states). When illumination is performed at a distance of 100 m using the imaging method as in the present invention, the enlargement ratio of the light source is significantly increased, making it difficult to finely control segments with illumination using conventional light-emitting elements. However, by using the minute and high-brightness light emitter (LED sheet) in the present invention, it is possible to finely divide the illumination area and control illumination and non-illumination by performing image-forming illumination. Become.

FIG. 23(a) is a side view of the low beam area.
FIG. 23(b) is a front view of the low beam area.
As shown in FIGS. 23(a) and 23(b), in the low-beam area, a non-illuminated area occurs near the center of the optical axis. This is because the high beam light source 22 is arranged in the center of the optical axis. The light source 23 has a magnification of about 130 at a point of 40 m, which is the irradiation position. The light source size at the object point is approximately 2.4 times larger than the light source 22 . Therefore, even if the high beam light source 22 is placed above the low beam light source 23 and the high beam light source 22 shields the vicinity of the optical axis center as in the present embodiment, the non-illuminated area is greatly reduced in the low beam state. Do not mean.

FIG. 24A is a schematic front view illustrating a high beam light source 22a according to another embodiment.
FIG. 24(b) is a side view of the high beam area.
FIG. 24(c) is a front view of the high beam area.
In the light source 22 described above, the light emitting elements are arranged only in the area corresponding to the center of the optical axis.

As shown in FIG. 24( a ), the light source 22 a is obtained by adding light sources 22 a 1 to the left and right of the light source 22 described above so as to have the same width as the light source 23 . As shown in FIG. 24(c), the light source 22a1, which is placed at the same distance from the focal point as the light source 22, has a size in which the illumination area of the light source 22 is expanded left and right above the optical axis. Become. In the present embodiment, the light source 22 has a spread of about 3m square, but by adding the light source 22a1, a spread of about 2m is generated in each of the left and right sides, making it possible to irradiate a point of 100m.

As described above, the light-emitting element assembly used in the light source of the present invention can also be integrated in a transparent sheet. When such transparent sheets are stacked, a wide area can be illuminated without creating a completely shielded space even in a low beam area. In this embodiment, the light source 22 for high beam and the light source 23 for low beam are each sheet-shaped, and the thickness direction pitch between the light sources is 1.5 mm. Illuminated at the position of the surface.

FIG. 25(a) is a schematic side view illustrating the arrangement of the light sources 22b and 23b.
FIG. 25(b) is a schematic front view illustrating the arrangement of the light sources 22b and 23b.
FIG. 26(a) is a schematic side view illustrating the arrangement of the light source 22b and the light source 23b.
FIG. 26(b) is a schematic front view illustrating the arrangement of the light sources 22b and 23b.
In the case of this embodiment, both the light source 22b and the light source 23b are configured to have a size of 24 mm square. The light source 22b had a light emitting surface separated from the focal position by 1 mm toward the object side, a thickness of 1.5 mm, and a light source 23b placed behind the light source 22b.

FIG. 27 is a schematic perspective view of the light sources 22b and 23b.
As shown in FIG. 27, the light sources 22b and 23b can have a plurality of integrated bodies (LED sheets) of light emitting elements having the same area.
FIG. 28(a) is a schematic side view of a region illuminated by the light source 23b.
FIG. 28(b) is a schematic plan view of the illuminated area by the light source 23b.
According to this embodiment, it is possible to irradiate an area of about 130 times 24 mm×24 mm at a point 40 m away. For example, as shown in FIG. 28(b), the illumination area can be approximately 3m×3m. The illumination and non-illumination areas within this area can be turned on/off according to the size of the segment of the aggregate of the light emitting elements.

FIG. 29(a) is a schematic side view of a region illuminated by the light source 22b.
FIG. 29(b) is a schematic plan view of the illuminated area by the light source 22b.
According to the present embodiment, it is possible to illuminate an area of about 7 m vertically and horizontally centering on the optical axis. In the case of this embodiment, since the center of the optical axis is about 1.5 m above the ground, a portion of about 2 m below is reflected on the road surface.

As described above, a semiconductor light emitting device according to embodiments of the present invention can comprise, for example, a projection lens and at least one light emitting diode sheet. The light-emitting portion of the light-emitting diode sheet can be arranged beyond the object-side focal length of the projection lens. The light-emitting diode sheet can include at least a first wiring, a light-emitting layer including a diode, a plurality of light-emitting elements in which the second wiring is stacked in order, and an insulating layer disposed between the plurality of light-emitting elements. . The light emitting layer is in direct contact with the first wiring, and the surface of the light emitting layer opposite to the surface in direct contact with the first wiring can be in direct contact with the second wiring.
In addition, the irradiation area can be changed by turning on/off an arbitrary light-emitting element among the plurality of light-emitting elements.
Also, a plurality of light emitting diode sheets may be provided, and at least a portion of the plurality of light emitting diode sheets may overlap in the thickness direction.
In addition, the insulating layer can have translucency.

Although some embodiments of the present invention have been illustrated above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, etc. can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof. Moreover, each of the above-described embodiments can be implemented in combination with each other.

1 semiconductor light emitting device 10 optical element 11 semiconductor light emitting device 20 light emitting part 20a light emitting part 22 light source 22a light source 22a1 light source 22b light source 23 light source 23b light source 30 light emitting diode sheet (LED sheet) 31 First wiring 32 First buffer layer 33 Emitting layer 34 Second wiring 35 Insulating layer 36 Space 40 Phosphor sheet 41 Fluorescent layer 42 Holding layer 50 Phosphor sheet 51 Fluorescent layer 52 Holding layer, 130 LED sheets

Claims (4)

a projection lens;
at least one light emitting diode sheet;
with
the light-emitting portion of the light-emitting diode sheet is arranged beyond the object-side focal length of the projection lens,
The light emitting diode sheet is
At least a first wiring, a light emitting layer including a diode, a plurality of light emitting elements in which the second wiring is stacked in order, and an insulating layer disposed between the plurality of light emitting elements,
the light emitting layer is in direct contact with the first wiring,
A semiconductor light-emitting device, wherein the surface of the light-emitting layer opposite to the surface directly in contact with the first wiring is in direct contact with the second wiring. 2. The semiconductor light-emitting device according to claim 1, wherein an irradiation area can be changed by turning on/off an arbitrary light-emitting element among the plurality of light-emitting elements. A plurality of the light emitting diode sheets are provided,
3. The semiconductor light-emitting device according to claim 1, wherein at least part of said plurality of light-emitting diode sheets overlap in the thickness direction. 4. The semiconductor light emitting device according to claim 1, wherein said insulating layer has translucency.

Images