TWI878020B - Light-emitting element and light-emitting device comprising the same - Google Patents

Abstract

A light-emitting device has a carrier, a contact arranged on the carrier, a semiconductor stack and an electrode electrically connected to the semiconductor stack and the contact.

Description

A light emitting element and a light emitting device thereof

The present invention relates to a light emitting device, and more particularly to a light emitting device comprising a pair of electrodes symmetrical to each other.

Light-emitting diodes (LEDs) have gradually replaced traditional incandescent lamps and fluorescent lamps in various lighting applications due to their advantages such as energy saving, long life, and small size.

The LED can be further bonded to a substrate through conductive materials such as solder to form a light-emitting device. However, during the bonding process, the conductive material flows during the solidification process, which may cause the LED on the conductive material to be pulled by the flowing conductive material and displaced, thereby making it impossible for the LED to be bonded to the correct position.

The aforementioned light-emitting device may include a primary carrier (sub-mount); a solder (solder) is located on the above-mentioned sub-carrier, and the light-emitting diode is bonded and fixed to the sub-carrier by the solder and the light-emitting diode is electrically connected to the circuit on the sub-carrier; wherein the above-mentioned sub-carrier can be a lead frame (lead frame) or a large-sized mounting substrate (mounting substrate).

The present invention discloses a light-emitting device, comprising a light-emitting element, a carrier, a first contact and a second contact. The light-emitting element comprises a first electrode and a second electrode. The first contact is disposed on the carrier and electrically connected to the first electrode, and the second contact is disposed on the carrier and electrically connected to the second electrode. The first contact has a similar outline to the first electrode, and the second contact has a similar outline to the second electrode.

The present invention discloses a light-emitting device, comprising a light-emitting element, a carrier, a first contact and a second contact. The light-emitting element comprises a first electrode and a second electrode surrounded by the first electrode. The first electrode has a first profile, and the second electrode has a second profile different from the first profile. The first contact is disposed on the carrier and electrically connected to the first electrode, the second contact is disposed on the carrier and electrically connected to the second electrode, and the second contact has a third profile.

The present invention discloses a light-emitting device, comprising a light-emitting element, a carrier, a first contact and a second contact. The light-emitting element comprises a first electrode and a second electrode having a first profile and surrounded by the first electrode. The first contact is disposed on the carrier and electrically connected to the first electrode, and the second contact having a second profile is disposed on the carrier and electrically connected to the second electrode.

FIG. 1 is a side view of a light emitting device according to an embodiment of the present invention. Referring to FIG. 1, the light emitting device 10 includes a semiconductor stack 2, a first electrode 40 and a second electrode 42, and the first electrode 40 and the second electrode 42 are physically separated from each other and do not contact each other. They can overlap each other (but separated by an insulating layer) or not overlap each other. In one embodiment, an insulating portion is formed between the first electrode 40 and the second electrode 42. The semiconductor stack 2 includes a first semiconductor layer of a first conductivity (not shown), a second semiconductor layer of a second conductivity (not shown), and a light-emitting layer (not shown) located between the first semiconductor layer and the second semiconductor layer, wherein the light-emitting layer can emit an incoherent light. The first semiconductor layer is electrically connected to the first electrode 40, and the second semiconductor layer is electrically connected to the second electrode 42.

The first semiconductor layer of the first conductivity and the second semiconductor layer of the second conductivity may serve as a cladding layer or a confinement layer, respectively providing electrons and holes that are combined in the light-emitting layer to emit light. The constituent materials of the first semiconductor layer of the first conductivity, the second semiconductor layer of the second conductivity and/or the light-emitting layer may include III-V semiconductor materials, such as _{AlxInyGa ( 1-xy )} N _{or AlxInyGa ( 1 -xy )} P, where 0≤x, y≤1; (x+y)≤1. Depending on the material of the light-emitting layer, the light-emitting element 10 can emit red light with a peak wavelength between 610nm and 650nm, green light with a peak wavelength between 530nm and 570nm, or blue light with a peak wavelength between 450nm and 490nm.

The electrodes 40, 42 are made of metal materials, such as titanium, nickel, gold, platinum or aluminum. In one embodiment, the electrodes 40, 42 are a multi-layer structure composed of titanium/aluminum/nickel/aluminum/nickel/aluminum/nickel/gold, titanium/aluminum/titanium/aluminum/nickel/gold, or titanium/platinum/aluminum/nickel/aluminum/nickel/gold, wherein the bottom layer is gold for direct contact with external components.

The light-emitting element 10 may further include a wavelength conversion material (not shown) covering the semiconductor stack 2. The wavelength conversion material can absorb the first light emitted by the semiconductor stack 2 and convert it into a second light with a peak wavelength or a main wavelength different from the first light. The wavelength conversion material includes quantum dot material, yellow-green fluorescent powder, red fluorescent powder or blue fluorescent powder. The yellow-green fluorescent powder includes YAG, TAG, silicate, valate, alkali earth metal selenide, or metal nitride. The red fluorescent powder includes fluoride (such as K ₂ TiF ₆ :Mn ⁴⁺ or K ₂ SiF ₆ :Mn ⁴⁺ ), silicate, vanadate, alkali earth metal sulfide, metal oxynitride, or a mixture of tungstate and molybdenum. The blue fluorescent powder includes BaMgAl ₁₀ O ₁₇ :Eu ²⁺ . In one embodiment, the first light and the second light are mixed into a white light, and the white light has a color point coordinate (x, y) in the CIE 1931 chromaticity diagram, wherein 0.27≦x≦0.285; 0.23≦y≦0.26. In one embodiment, the white light has a color temperature between 2200 and 6500K (e.g., 2200K, 2400K, 2700K, 3000K, 5700K, 6500K) and has a color point coordinate (x, y) located within the 7th order MacAdam ellipse in the CIE 1931 chromaticity diagram. In one embodiment, the first light and the second light are mixed into a non-white light, such as red light, amber light, purple light, or yellow light. In one embodiment, the first light can be almost entirely or mostly converted into the second light.

Quantum dot materials can be composed of a core and a shell. The core and the shell can be composed of different semiconductor materials. The shell material has a higher energy barrier than the core material, which can reduce the excessive electrons emitted by the core material during the repeated emission of light, thereby reducing the brightness attenuation of the quantum dot material. The core material can be selected from zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), zinc oxide (ZnO), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), gallium nitride (GaN), gallium phosphide (GaP), gallium selenide (GaSe), gallium antimonide (GaSb), gallium arsenide (GaAs), aluminum nitride (AlN), aluminum phosphide (AlP), aluminum arsenide (AlAs), indium phosphide (InP), indium arsenide (InAs), tellurium (Te), lead sulfide (PbS), indium antimonide (InSb), lead telluride (PbTe), lead selenide (PbSe), antimony telluride (SbTe) , zinc cadmium selenide (ZnCdSe), zinc cadmium selenide (ZnCdSeS), and copper indium sulfide (CuInS). The shell material and the core material must match each other (for example, the lattice constants of the core and shell materials need to match). Specifically, the choice of the shell material composition, in addition to matching the lattice constant of the core material, is also to form a high energy barrier region around the core to increase the quantum yield. In order to satisfy both properties at the same time, the shell structure and/or composition can be changed to reduce the stress in the core and shell on the one hand, and raise the energy barrier on the other. The shell structure can be a single layer, multi-layer, or a structure with a gradient material composition. In one embodiment, the core is cadmium selenide and the shell is a single layer of zinc sulfide. In another embodiment, the core is cadmium selenide and the shell comprises an inner layer of (cadmium, zinc) (sulfur, selenium) and an outer layer of zinc sulfide. In another embodiment, the core is cadmium selenide and the shell comprises an inner layer of cadmium sulfide, a middle gradient layer of Zn _0.25 Cd _0.75 S/Zn _0.5 Cd _0.5 S/Zn _0.75 Cd _0.25 S, and an outer layer of zinc sulfide.

The light-emitting element 10 may also include a carrier, which can be used to carry or support the light-emitting layer. In one embodiment, the carrier is a substrate that can be used for epitaxial growth, and the material of the substrate is, for example, sapphire, gallium nitride, silicon, silicon carbide, etc., which is suitable for forming (for example, epitaxial growth technology) semiconductor materials of group III-V or group II-VI that can form a light-emitting layer thereon. In another embodiment, the carrier is not a growth substrate for directly forming a light-emitting layer, but is used to replace or support other supporting members of the growth substrate (the supporting member is, for example, a structure whose material, composition, or shape is different from that of the growth substrate).

FIG. 2 is a bottom view of the light-emitting element 10 of FIG. 1, wherein the first electrode 40 and the second electrode 42 are similar in shape and are symmetrical with respect to a virtual line L0, and the first electrode 40 and the second electrode 42 do not overlap with the virtual line L0. The virtual line L0 is a virtual line for schematic purposes and is not a specific line segment visible to the naked eye on the light-emitting element 10, and the virtual line L0 in the figure overlaps with the geometric center (not shown) of the light-emitting element 10. Referring to FIG. 2, the semiconductor stack 2 and the light-emitting layer (not shown) inside have a square outline, and the light-emitting layer can be used to provide a light field with a square outline. In one embodiment, the shortest distance between the first electrode 40 and the second electrode 42 is greater than 150 μm.

FIG. 3 is a side view of a light emitting device according to an embodiment of the present invention. Referring to FIG. 3 , the light emitting device 1000 includes a semiconductor stack 2, a first electrode 40 and a second electrode 42, conductive layers 101, 102, a first contact 400, a second contact 420, and a carrier 300. The carrier 300 includes a circuit (not shown), which electrically connects the first electrode 40 and the second electrode 42, so that an external power source can provide power through the conductive layers 101, 102 and the electrodes 40, 42 to make the light emitting device 1000 emit light. Referring to FIG. 4, FIG. 4 shows the relative positions of the carrier 300 and the conductive layers 101 and 102 thereon in FIG. 3, and omits the semiconductor stack 2, the first electrode 40, and the second electrode 42. The first contact 400 and the second contact 420 are formed on the upper surface of the carrier 300, and are electrically connected to the semiconductor stack 2 through the conductive layers 101 and 102. The conductive layers 101 and 102 on the first contact 400 and the second contact 420 may have different profiles and are formed on the first contact 400 and the second contact 420 in an asymmetric manner (relative to the virtual line L0). The first contact 400 and the second contact 420 are similar in shape and are symmetrical with respect to a virtual line L0, and the first contact 400 and the second contact 420 do not overlap with the virtual line L0. The first contact 400 is similar in outline to the first electrode 40, and the second contact 420 is similar in outline to the second electrode 42. The first contact 400 and the second contact 420 can be electrically connected to a circuit (not shown) on the carrier 300. The conductive layer 101 electrically connects the first electrode 40 and the first contact 400, and the conductive layer 102 electrically connects the second electrode 42 and the second contact 420, and fixes the semiconductor stack 2 on the carrier 300. It is worth noting that the conductive layers 101 and 102 contact the first contacts 400 and the second contacts 420 on the carrier 300 and the areas on the carrier 300 that are not covered by the first contacts 400 or the second contacts 420. The bonding force between the conductive layers 101 and 102 and the first contacts 400 and the second contacts 420 is stronger than the bonding force between the conductive layers 101 and 102 and the areas on the upper surface of the carrier 300 that are not covered by the first contacts 400 or the second contacts 420. Good adhesion between the conductive layer and the contact can prevent the conductive layers 101, 102 from being gathered in large quantities on the carrier 300 where there is no first contact 400 or second contact 420 during the manufacturing process, and instead there is no conductive layer 101, 102 on the first contact 400 or second contact 420, thereby causing a disconnection between the semiconductor stack 2 and the circuit of the carrier 300. In addition, good adhesion can also prevent the conductive layers 101, 102 from being peeled off from the surface of the first contact 400, the second contact 420 or the carrier 300, thereby preventing the light-emitting element 10 from being separated from the carrier 300 together with the conductive layers 101, 102. In one embodiment, the shortest distance between the first contact 400 and the second contact 420 is greater than 150 μm.

FIG. 4 is a top view of the carrier 300 in FIG. 3. Referring to FIG. 4, the first contact 400 (second contact 420) is composed of a branch (region A) and a main body (such as region B). During the manufacturing process, a conductive material is covered on the first contact 400 and the second contact 420. The conductive material can be solder or other conductive adhesive materials. Then, the light-emitting element 10 is pressed down and fixed on the first contact 400 and the second contact 420. At the same time, the conductive material is fixed to form conductive layers 101 and 102. During the pressing process, due to the different amounts of conductive material covering the first contact 400 and the second contact 420, the difference in roughness on the first contact 400 and the second contact 420, or the unequal forces applied to the first contact 400 and the second contact 420 during the pressing process, the conductive material may flow on the first contact 400 and the second contact 420, thereby forming a situation in which the conductive layers 101 and 102 have different shapes as shown in FIG. 4 . Therefore, the present invention utilizes the characteristic that the bonding force between the conductive material and the first contact 400 and the second contact 420 is greater than the bonding force between the conductive material and the carrier 300, and designs the first contact 400 and the second contact 420 to have a structure with area B and area A, so that during the pressing process, the conductive material mainly flows to area A or area B, which is the same material and has a greater bonding force relative to the surface of the carrier 300, thereby avoiding the conductive material from flowing everywhere (for example, flowing to the carrier 300 where the first contact 400 and the second contact 420 are not located), so that the conductive material can remain on the first contact 400, the second contact 420 and between the electrodes 40, 42.

In addition, it is worth noting that the maximum width of the branch (e.g., region A) in the first contact 400 and the second contact 420 is smaller than the maximum width of the main body (e.g., region B). This allows the branch to attract less conductive material than the main body, thereby preventing the conductive material from simultaneously contacting the two contacts 400 and 420 through the branch to form a short circuit. At the same time, even if the light-emitting element 10 moves due to the flow of the conductive layer material during the manufacturing process, it is not easy for the first contact 400 and the second contact 420 to be electrically connected to the same electrode 40 or 42 on the light-emitting element 10 at the same time due to excessive conductive material, resulting in a short circuit.

The conductive material can be solder or anisotropic conductive paste (ACP). Anisotropic conductive paste includes conductive pastes such as paste containing micro-solder balls or ultra-fine pitch fixed array anisotropic conductive paste (ultra-fine pitch fixed array ACP). Among them, the paste containing micro-solder balls can be PAL-ACF (particle-aligned anisotropic conductive film), ACF (Anisotropic Conductive film), SAP (Self Assembly Anisotropic Conductive Paste) or epoxy solder pate.

FIG. 5 is a cross-sectional view of a light-emitting device according to an embodiment of the present invention. The light-emitting device 20 comprises a semiconductor stack 2 and an electrode portion 6. The electrode portion 6 comprises a first electrode 60, a second electrode 62, and a first insulating portion 61 between the first electrode 60 and the second electrode 62. For details of the semiconductor stack 2, please refer to the relevant paragraphs in the aforementioned embodiment, and for the sake of brevity, the description is not repeated. The electrode portion 6 protrudes above the semiconductor stack 2 and has a substantially flat surface on a side away from the semiconductor stack 2. FIG. 6 is a bottom view of the light-emitting device of FIG. 5. Referring to FIG. 6 , the electrode portion 6 has a square outline, and the second electrode 62 and the first insulating portion 61 surrounding the second electrode 62 form a concentric structure. The concentric structure has a center C1 in the plan view of FIG. 6 . The first electrode 60, the first insulating portion 61 and the second electrode 62 all protrude outside the semiconductor stack 2, and all have the same height and a substantially flat outermost surface for electrical connection with other components. The center C1 of the second electrode 62 substantially overlaps with the geometric center of the light-emitting element 20, and the second electrode 62 has a semi-diameter R1, and the insulating portion 61 has a semi-diameter R2 from the center C1. The first electrode 60 and the second electrode 62 are physically separated from each other by the first insulating portion 61, do not contact each other, and do not overlap each other, and are each electrically connected to a semiconductor layer of different electrical properties in the semiconductor stack 2. The first insulating portion 61 surrounds the second electrode 62 and has the same profile as the second electrode 62. In one embodiment, the first insulating portion 61 and the second electrode 62 have similar profiles, such as a circle or an ellipse. In other embodiments, the first insulating portion 61 and the second electrode 62 may also have the shape of a quadrilateral, a triangle, a polygon, or a closed curve. 6 , the first electrode 60 has a profile similar to that of the semiconductor stack 2, and the outermost edge of the first electrode 60 does not overlap with the outermost edge of the semiconductor stack 2. The light-emitting element 20 has a square profile, and the semiconductor stack 2 and the light-emitting layer (not shown) therein have the same profile as the light-emitting element 20. In other words, the semiconductor stack 2 has a square profile, and the light-emitting layer (not shown) also has a square profile. In one embodiment, the narrowest width of the first insulating portion 61 is greater than 150 μm to prevent the electrodes 60 , 62 from overlapping and causing a short circuit during the process of manufacturing the first electrode 60 and the second electrode 62 .

The material of the insulating portion 61 may be an oxide, a nitride or a polymer. Oxides include silicon oxide ( _SiOx ), titanium oxide ( _TiOx ), tantalum oxide ( _TaOx ) or aluminum oxide ( _AlOx ). Nitrides include aluminum nitride ( _AlNx ) or silicon nitride ( _SiNx ). Polymers include polyimide or benzocyclobutane (BCB). In another embodiment, the insulating portion 61 includes a plurality of sub-layers of repeatedly stacked low refractive index layers and high refractive index layers to form a Bragg reflector (DBR).

FIG. 7 is a cross-sectional view of a light emitting device according to an embodiment of the present invention. FIG. 8 is a top view of the carrier 300 in FIG. 7. In FIG. 7, the light emitting device 2000 includes a light emitting element 20 fixedly connected to the carrier 300 through a conductive layer 103. Referring to FIG. 8, the carrier 300 is provided with a first contact 600, a second contact 620, and a second insulating portion 610 isolating the first contact 600 and the second contact 620. The first contact 600, the second contact 620, and the second insulating portion 610 are substantially at the same height and have a flat surface. The first contact 600, the second contact 620 and the second insulating portion 610 have a substantially circular outline in the plan view of FIG. 8, and the first contact 600, the second contact 620 and the second insulating portion 610 form a concentric circle structure having a center C2 in the plan view of FIG. 8. The second contact 620 has a center C2 and a semi-diameter R3, and the second insulating portion 610 has a semi-diameter R4 from the center C2. In one embodiment, the center C2 overlaps with the geometric center of the carrier 300. In another embodiment, the narrowest width of the second insulating portion 610 is greater than 150 μm. In one embodiment, a plurality of light-emitting elements 20 may be disposed on the carrier 300. More specifically, a plurality of sets of first contacts 600 and second contacts 620 separated by a second insulating portion 610 are disposed on the carrier 300, so that each set of first contacts 600 and second contacts 620 can be electrically connected to a light-emitting element 20. As shown in FIG. 7, the light-emitting element 20 is fixed to the carrier 300 through the conductive layers 103 and 104, the first electrode 60 of the light-emitting element 20 is electrically connected to the first contact 600 through the conductive layer 103, the second electrode 62 is electrically connected to the second contact 620 through the conductive layer 104, and the first insulating portion 61 is substantially connected to the second insulating portion 610. The material of the conductive layers 103 and 104 can be solder or anisotropic conductive paste (ACP). Referring to FIG. 7 , the edge shape of the conductive layers 103 and 104 is arc-shaped. The center C1 of the second electrode 62 is roughly connected to the center C2 of the second contact 620. In this embodiment, the first contact 600, the second contact 620, the second insulating portion 610, the second electrode 62 and the first insulating portion 61 all have a circular profile. The radius R1 of the second electrode 62 is not greater than the radius R4 of the second insulating portion 610 to prevent the second electrode 62 from being electrically connected to the first contact 600 and the second contact 620 at the same time. The radius R3 of the second contact 620 is not greater than the radius R2 of the first insulating portion 61, so as to prevent the first electrode 60 and the second electrode 62 from being electrically connected to the second contact 620. The two sides of the conductive layers 103 and 104 are respectively connected to the light emitting element 20 and the carrier 300. On one side of the carrier 300, when the conductive layers 103 and 104 are in contact with the second insulating portion 610, the bonding force between the conductive layers 103 and 104 and the first contacts 600 and the second contacts 620 is preferably greater than the bonding force between the conductive layers 103 and 104 and the second insulating portion 610. On one side of the light-emitting element 20, when the conductive layers 103, 104 are in contact with the second insulating portion 610, the bonding force between the conductive layers 103, 104 and the first electrode 60, the second electrode 62 is preferably greater than the bonding force between the conductive layers 103, 104 and the first insulating portion 61. The surfaces of the first contact 600, the second contact 620 and the second insulating portion 610 are substantially flush to match the substantially flat surface of the electrode portion 6 of the light-emitting element 20. In one embodiment, the electrode portion 6 of the light-emitting element 20 has a non-flat surface including a protrusion and/or a recess. For example, the thickness of the second electrode 62 and the first insulating portion 61 is greater than the thickness of the first electrode 60. In contrast, the surfaces of the second contact 620 and the second insulating portion 610 of the carrier 300 are more concave than the surface of the first contact 600 to match the protruding shape of the electrode portion 6; and the conductive layer 104 also fills the concave portion of the carrier 300, so that the second electrode 62 can be electrically connected to the second contact 620 through the conductive layer 104, and the conductive layer 103 can be electrically connected to the first electrode 60 and the first contact 600.

FIG. 9 is a cross-sectional view of a light-emitting element of an embodiment of the present invention. The light-emitting element 30 includes a carrier 204, a first semiconductor layer 201 having a first conductivity, a light-emitting layer 202, a second semiconductor layer 203 having a second conductivity, a first electrode 80, a second electrode 82, and a groove portion 81 located between the first electrode 80 and the second electrode 82. The first conductivity and the second conductivity can be N-type and P-type, or P-type and N-type, respectively. The first semiconductor layer 201 includes a raised portion 201U, and the light-emitting layer 202 is formed on the raised portion 201U and can emit an incoherent light. Referring to FIG. 9, the raised portion 201U is approximately located at the center of the first semiconductor layer 201, and is also approximately located at the center of the light-emitting element 30. In one embodiment, the uppermost surface of the first semiconductor layer 201 is a plane of substantially equal height, and the light-emitting layer 202 is formed on the plane of substantially equal height and is located at the center of the first semiconductor layer 201, and the center point (not shown) of the light-emitting layer 202 is substantially aligned with the center point (not shown) of the first semiconductor layer 201. The first semiconductor layer 201 is electrically connected to the first electrode 80, and the second semiconductor layer 203 is electrically connected to the second electrode 82. FIG. 10 is a top view of the light-emitting element 30 of FIG. 9. Referring to FIG. 10, the second electrode 82 has a circular profile, and the groove portion 81 surrounding the second electrode 82 has a circular profile substantially the same as that of the second electrode 82. The second electrode 82 and the groove portion 81 surrounding the second electrode 82 form a concentric circle structure. This concentric circle structure has a center C3 in the plan view of FIG. 10. The second electrode 82 has a semi-diameter R5, and the groove portion 81 has a semi-diameter R6 from the center C3. The contours of the light-emitting layer 202 and the second electrode 82 are roughly the same circle, so the light-emitting element 30 has a circular light-emitting area. The outer contour of the first electrode 80 is not limited to the state in FIG. 10, and the outer contour of the first electrode 80 can be various shapes formed by a circle or other closed curves. The groove portion 81 has a substantially equal width in the plan view of FIG. 10. The groove portion 81 contains air. In one embodiment, the narrowest width of the groove portion 81 is greater than 150μm. In one embodiment, the groove portion 81 further includes an insulating material for electrically isolating the first electrode 80 from the light-emitting layer 202, the second semiconductor layer 203, and the second electrode 82. The insulating material may fill the entire groove portion 81, or only a portion of the groove portion 81 may be covered by the insulating material, such as the sidewall of the first electrode 80 close to the light-emitting layer 202, the sidewall of the light-emitting layer 202 close to the first electrode 80, the sidewall of the second semiconductor layer 203 close to the first electrode 80, and/or the sidewall of the second electrode 82 close to the first electrode 80.

In one embodiment, the carrier 204 is a substrate that can be used for epitaxial growth. The material of the substrate is, for example, sapphire, gallium nitride, silicon, silicon nitride, etc., which is suitable for forming (for example, epitaxial growth technology) semiconductor materials of group III-V or group II-VI that can form a light-emitting layer thereon. In another embodiment, the carrier 204 is not a material layer or a growth substrate for directly forming a light-emitting layer, but is used to replace or support other supporting members of the growth substrate (the supporting member is, for example, a structure whose material, structure, or shape is different from that of the growth substrate).

Referring to FIG. 10 , the light-emitting layer 202 and the second electrode 82 have substantially the same profile and a circular profile to provide a circular light-emitting area, and the light-emitting layer 202 has substantially the same optical properties in all directions, including the light intensity, the main wavelength of the emitted light, and/or the peak wavelength of the emitted light. The circular profile also has the advantage of being easy to manufacture. For example, in the process of bonding the light-emitting element 30 to the carrier through the conductive layer, even if the light-emitting element 30 is rotated 45 degrees from the originally predetermined position, the circular second electrode 82 can still be correctly connected to the conductive area on the carrier, and the first electrode 80 will not be connected to the conductive area of the second electrode 82 that is to be connected. In contrast, when the electrode does not have a circular profile, such as the electrodes 40 and 42 in FIG. 1 , if the light-emitting element 10 is rotated during the bonding process (e.g., rotated 45 degrees from the originally predetermined position), the electrode 40 (and/or 42) has a chance to simultaneously dock with the two contacts 400 and 420 to form a short circuit and cause the light-emitting element 10 to burn out.

FIG. 11 is a cross-sectional view of a light-emitting device according to an embodiment of the present invention. FIG. 12 is a top view of the carrier 301 in FIG. 11. The light-emitting device 3000 includes a light-emitting element 30 fixedly connected to the carrier 301 through conductive layers 105 and 106. For details of the light-emitting element 30, please refer to the relevant paragraphs in the aforementioned embodiment. The light-emitting device 3000 does not fill the groove 81 with solid material, so the space between the first semiconductor layer 201 and the carrier 301 is substantially filled with air. The carrier 301 is provided with a first contact 800, a second contact 820 and a third insulating portion 810 isolating the first contact 800 and the second contact 820. The second electrode 82 is electrically connected to the second contact 820 through the conductive layer 106. The first electrode 80 is electrically connected to the first contact 800 through the conductive layer 105. The conductive layer 105 and the conductive layer 106 do not contact each other. From the side view, the edge shape of the conductive layer 105 and the conductive layer 106 is an arc.

Referring to FIG. 12 , the first contact 800, the second contact 820, and the third insulating portion 810 surrounding the second contact 820 form a concentric circle structure. The concentric circle structure has a center C4 in the plan view of FIG. 12 . The second contact 820 has a radius R7 from the center C4, and the third insulating portion 810 has a radius R8 from the center C4. The first contact 800, the second contact 820, and the third insulating portion 810 are substantially equal in height and have a flat surface. In one embodiment, the narrowest width of the third insulating portion 810 is greater than 150 μm. Therefore, when the light-emitting element 30 and the carrier 301 are joined, if there is a deviation in the alignment of the light-emitting element 30 and the carrier 301, for example, there is an error of a distance d between the position of the light-emitting element 30 and the predetermined distance, when the distance d is less than the narrowest width of the third insulating portion 810, the light-emitting device 3000 can still operate normally without the first electrode 80 and the second contact 820 being in contact with each other, or the second electrode 82 and the first contact 800 being in contact with each other. In one embodiment, a plurality of light-emitting elements 30 may be disposed on the carrier 301. More specifically, a plurality of groups of first contacts and second contacts separated by insulating portions are disposed on the carrier 301, so that each group of first contacts 800 and second contacts 820 can be electrically connected to a light-emitting element 30. As shown in FIG. 11, the light-emitting element 30 is fixed to the carrier 301 through the conductive layers 105 and 106. The first contacts 800, the second contacts 820, the third insulating portion 810, and the second electrode 82 all have similar profiles, such as a circle. In other embodiments, the groove portion 81 and the second electrode 82 may also have a quadrilateral, triangle, polygon, or closed curve profile. Referring to Figures 10, 11, and 12, the radius of the second electrode 82 is not larger than the maximum radius of the third insulating portion 810, so as to avoid electrical connection between the second electrode 82 and the first contact 800. Also, the radius of the second contact 820 is not larger than the maximum radius of the groove portion 81, so as to avoid electrical connection between the first electrode 80 and the second contact 820. The two sides of the conductive layers 105 and 106 are connected to the light emitting element 30 and the carrier 301, respectively. On the carrier 301 side, the bonding force between the conductive layer 105 and the first contact 800, and the bonding force between the conductive layer 106 and the second contact 820 are both greater than the bonding force between the conductive layer 105 or the conductive layer 106 and the third insulating portion 810. In one embodiment, the third insulating portion 810 contacts the conductive layers 105 and 106, but the bonding force between the third insulating portion 810 and the conductive layers 105 and 106 is smaller than the bonding force between the conductive layer 105 and the first electrode 80, and also smaller than the bonding force between the conductive layer 106 and the second electrode 82. The surfaces of the first contact 800, the second contact 820 and the third insulating portion 810 are substantially flush to match the electrodes 80, 82 of substantially the same height of the light emitting element 30. In one embodiment, the first contact 800, the second contact 820 and the third insulating portion 810 are protruding or concave to match the surface morphology of the electrodes 80, 82, so that the contacts and the electrodes can be tightly bonded.

FIG. 13 is a bottom view of a light-emitting element of an embodiment of the present invention. The structure of the light-emitting element 30' is roughly similar to that of the light-emitting element 30. For the relevant description, please refer to the relevant paragraphs in the aforementioned embodiment. The light-emitting element 30' has a circular outline. From FIG. 13, the outlines of the first electrode 80, the second electrode 82 and the groove portion 81 of the light-emitting element 30' are roughly concentric circles. Since the outline of the light-emitting element 30' and the outline of the light-emitting layer (not shown) are both circular, the optical characteristics of the light-emitting element 30' in all directions are roughly the same. Furthermore, during the process of joining the light-emitting element 30' to the carrier (e.g., the carrier 301 in FIG. 12 ), even if the light-emitting element 30' is rotated, the first electrode 80 or the second electrode 82 of the light-emitting element 30' will not simultaneously contact two different contacts (e.g., the first contact 800 and the second contact 820 in FIG. 12 ) on the carrier (e.g., the carrier 301 in FIG. 12 ) to cause a short circuit.

FIG. 14 is a cross-sectional view of a light emitting device according to an embodiment of the present invention. The light emitting device 4000 includes a light emitting element 30 fixedly connected to a carrier 301 through a conductive layer 107. The light emitting device 4000 is similar to the light emitting device 3000. For details, please refer to the relevant paragraphs in the aforementioned embodiment. It is worth noting that the conductive layer 107 is a continuous layer, which simultaneously connects the first electrode 80 and the carrier 301, and the second electrode 82 and the carrier 301. The conductive layer 107 includes a first region 107A, a second region 107B, and a third region 107C, wherein the first region 107A is electrically connected to the first electrode 80 and the first contact 800 on the carrier 301, the second region 107B is electrically connected to the second electrode 82 and the second contact 820 of the carrier 301, and the first region 107A and the second region 107B are isolated from each other by the third region 107C. Further, the first region 107A and the second region 107B contain conductive particles of sufficient concentration and quantity, thereby achieving the effect of electrically connecting the light-emitting element 30 and the conductive region on the carrier 301 (in a direction perpendicular to the surface where the carrier 301 and the conductive layer 107 are connected). The third region 107C does not contain any conductive particles, or contains only a small amount of conductive particles, which is insufficient to electrically connect the first region 107A and the second region 107B (in a direction parallel to the surface where the carrier 301 and the conductive layer 107 are connected), and is also insufficient to electrically connect the light-emitting element 30 and the conductive region on the carrier 301 (in a direction perpendicular to the surface where the carrier 301 and the conductive layer 107 are connected). The difference in the amount/concentration of conductive particles in each region of the conductive layer 107 may be caused during the manufacturing process of the light-emitting device 4000. Specifically, when the conductive material of the conductive layer 107 covers the carrier 301, the conductive particles in the conductive material are initially roughly evenly distributed, but in the process of placing the light-emitting element 30 and connecting it to the carrier 301, the conductive material is pressed or heated to form the conductive layer 107, and the conductive particles in the third region 107C move to the regions 107A and 107B. It can also be a pre-formed difference, for example, the conductive layer 107 is pre-formed so that the number/concentration of conductive particles in the third region 107C is lower than the number/concentration of conductive particles in the regions 107A and 107B, so as to achieve a vertical conductive effect in a specific region and electrically isolate a part of the region (in a direction parallel to the surface of the carrier 301 connected to the conductive layer 107). In one embodiment, the height of the conductive layer 107 is not uniform, and the height of the third region 107C between the first region 107A and the second region 107B is lower. The conductive layer 107 is similar to the conductive layers 105 and 106. From FIG. 14 , the edge of the conductive layer 107 is also an arc shape.

The embodiments described above are only for illustrating the technical ideas and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly. They should not be used to limit the patent scope of the present invention. In other words, any equivalent changes or modifications made according to the spirit disclosed by the present invention should still be covered by the patent scope of the present invention.

10, 20, 30, 30': light-emitting element 1000, 2000, 3000, 4000: light-emitting device 2: semiconductor stack 201, 203: semiconductor layer 202: light-emitting layer 81: groove part 40, 42, 60, 62, 80, 82: electrode 6: electrode part 61, 610, 810: insulation part 204, 300, 301: carrier 101, 102, 103, 104, 105, 106, 107: conductive layer 400, 420, 600, 620, 800, 820: contact A, B, 107A, 107B, 107C: Area L0, L1: Virtual line C1, C2, C3, C4: Center R1, R2, R3, R4, R5, R6, R7, R8: Radius

FIG. 1 is a side view of a light emitting element according to an embodiment of the present invention;

FIG. 2 is a bottom view of the light emitting element of FIG. 1;

FIG3 is a side view of a light emitting device according to an embodiment of the present invention;

FIG. 4 is a view of the carrier board in FIG. 3;

FIG5 is a cross-sectional view of a light emitting element according to an embodiment of the present invention;

FIG6 is a bottom view of the light emitting element of FIG5;

FIG7 is a cross-sectional view of a light emitting device according to an embodiment of the present invention;

FIG. 8 is a view of the carrier board in FIG. 7;

FIG9 is a cross-sectional view of a light emitting element according to an embodiment of the present invention;

FIG10 is a top view of the light emitting element of FIG9;

FIG11 is a cross-sectional view of a light emitting device according to an embodiment of the present invention;

FIG. 12 is a view of the carrier board of FIG. 11;

FIG. 13 is a bottom view of a light emitting element according to an embodiment of the present invention;

FIG. 14 is a cross-sectional view of a light emitting device according to an embodiment of the present invention.

20: Light-emitting element

2: Semiconductor stack

40, 42: Electrode

L0, L1: virtual line

Claims (10)

A light-emitting device comprises: a light-emitting element comprising a first electrode and a second electrode, wherein the second electrode is completely surrounded by the first electrode; a carrier; a first contact disposed on the carrier and facing the first electrode; a first conductive layer electrically connecting the first electrode and the first contact; a second contact disposed on the carrier, facing the second electrode and surrounded by the first contact; and a second conductive layer electrically connecting the second electrode and the second contact, The first conductive layer is not flush with the outermost side of the first electrode, the second conductive layer is not flush with the outermost side of the second electrode, the first contact is similar to the outline of the first electrode, and the second contact is similar to the outline of the second electrode. A light-emitting device as described in claim 1, wherein the first electrode and the second electrode have similar profiles. A light-emitting device as described in claim 1, wherein the second electrode is circular. A light-emitting device as described in claim 1, wherein the first electrode is circular. A light-emitting device as described in claim 1, wherein the contours of the first electrode and the second electrode are substantially concentric circles. A light-emitting device as described in claim 1, wherein the outline of the first electrode or the second electrode is not a quadrilateral. The light emitting device as described in claim 1, wherein the first conductive layer and the second conductive layer include ACF (Anisotropic Conductive Film), SAP (Self Assembly Anisotropic Conductive Paste) or epoxy solder pate. A light-emitting device as described in claim 1, wherein the light-emitting element has a semiconductor stack, and in a top view, the outline of the semiconductor stack is similar to or different from that of the second electrode. A light-emitting device as described in claim 8, wherein the outline of the semiconductor stack is circular. A light-emitting device as described in claim 1, wherein the first electrode and the second electrode have different thicknesses.

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