Patent ID: 12255188

DETAILED DESCRIPTION OF THE EMBODIMENTS

The drawings illustrate the embodiments of the application and, together with the description, serve to illustrate the principles of the application. The same name or the same reference number given or appeared in different paragraphs or figures along the specification should has the same or equivalent meanings while it is once defined anywhere of the disclosure. The thickness or the shape of an element in the specification can be expanded or narrowed.

FIG.1is a top view of a light-emitting device100in accordance with an embodiment of the present disclosure. The light-emitting device100can be used for indoor or outdoor display. The light-emitting device100can emit a white light. The light-emitting device100includes a first light-emitting unit1, a second light-emitting unit2, a third light-emitting unit3, and a supporting body4. The first light-emitting unit1can be a red light-emitting diode having a peak/dominant wavelength ranging of 600 nm to 720 nm. The second light-emitting unit2can be a blue light-emitting diode having a peak/dominant wavelength ranging of 430 nm to 490 nm. The third light-emitting unit3can be a green light-emitting diode having peak/dominant wavelength ranging of 510 nm to 570 nm. The first light-emitting unit1, the second light-emitting unit2, and the third light-emitting unit3are disposed on the supporting body4. The supporting body4can be a lead frame or a substrate. The lead frame can include a plurality of conductive terminals (not shown) for electrically connecting the light-emitting units, and a housing (not shown) covering at least a portion of the conductive terminals. Wherein, the housing can optionally have a recess for accommodating the light-emitting units. The material of the substrate can comprise metal, thermoplastic material, thermosetting material, or ceramic material. The metal can comprise aluminum, copper, and the like. The thermosetting material can comprise phenolic resin, epoxy resin, bismaleimide triazine resin, or combination thereof. The thermoplastic material can comprise polyimide resin, polytetrafluorethylene or the like. The ceramic materials can include alumina, aluminum nitride, tantalum carbide, and the like.

The light-emitting unit can be a semiconductor light-emitting element which can emit the non-coherent light and includes a carrier, a first semiconductor layer, an active stack, and a second semiconductor layer. The first semiconductor layer and the second semiconductor layer can be cladding layer or confinement layer. The first semiconductor layer and the second semiconductor layer can provide electrons and holes respectively. The electrons and holes are combined in the active stack to emit light. The first semiconductor layer, the active stack, and the second semiconductor layer can include a semiconductor material of III-V group, such as AlxInyGa(1-x-y)N or AlxInyGa(1-x-y)P, where 0≤x≤1; 0≤y≤1; (x+y)≤1. Based on the material of the active stack, the light-emitting unit can emit an infrared light, a red light, a green light, a blue light, a violet light, or a ultra-violet light. The carrier can be a growth substrate for epitaxially growing the first semiconductor layer, the active stack, and the second semiconductor layer in sequence thereon; or be a support for the first semiconductor layer, the active stack, and the second semiconductor layer in sequence located thereon after removing the growth substrate. The growth substrate can be made of a material, such as Ge, GaAs, InP, sapphire, SiC, Si, GaN. The support can be LiAlO2, ZnO, AlN, metal, glass, diamond, CVD diamond, Diamond-Like Carbon (DLC). In an embodiment, the light-emitting unit does not have a growth substrate or a support, and has a thickness of about 5 to 10 μm.

When the size of the light-emitting unit is miniaturized, for example, the length or width of the light-emitting unit is less than 100 μm, or the light-emitting area is less than 2500 μm2, the influence of non-radiative recombination becomes apparent so that the external quantum efficiency (EQE) of the light-emitting diode decreases and the brightness decreases. When the material of the active stack comprises Al, In, Ga, P, and/or As, the light-emitting unit can emit a red light and have a carrier surface recombination velocity (SRV) of about 1×105(cm/s), which is faster than those of other materials used for emitting a blue light and a green light, for example, the SRV of gallium nitride (GaN) is about 1×104(cm/s). When the light-emitting unit can emit a red light and contains a material of Al, In, Ga, P, and/or As, the diffusion length is longer than that of the material of GaN, wherein the diffusion length is about 2 μm. In other words, there is no light emitted in a peripheral region of the light-emitting unit, where in the peripheral region has a width of 2 μm from the edge of the active stack. When the active stack of the light-emitting unit is gallium nitride (GaN), the light-emitting unit can emit a blue light and has a diffusion length is shorter than that of light-emitting unit which can emit a red light. The diffusion length of the light-emitting unit which can emit a blue light is about several hundred nm and less than 2 μm. Therefore, when the size of the light-emitting unit is miniaturized and the material is nitride-based, the non-radiative recombination effect occurring on the edge of the active stack is small, and the area of the non-light-emitting area is also small. By contrast, when the material is Al, In, Ga, P, or As-based, the non-radiative recombination effect on the edge of the active stack is substantial and the area of the non-light-emitting area is large, so that the luminous efficiency and external quantum efficiency (EQE) is degraded.

In one embodiment shown inFIG.1, the first light-emitting unit1emits a red light, the second light-emitting unit2emits a blue light, and the third light-emitting unit3emits a green light. When each of the light-emitting areas (projected area of the active layer) of the light-emitting units1,2, or3is about 1500 μm2, for example, the light-emitting unit has a rectangular shape with a length of 50 μm and a width of 30 μm, or the light-emitting unit has a circle shape with a radius of 22 μm, the external quantum efficiency (EQE) of the first light-emitting unit1is about 7%, the external quantum efficiency (EQE) of the second light-emitting unit2is about 27%, and the external quantum efficiency (EQE) of the third light-emitting unit3is about 25%. Therefore, in the case of the light-emitting device100, the luminous efficiency of the first light-emitting unit1is only about ¼ of that of the second light-emitting unit2. The luminous efficiency of the first light-emitting unit1is only about ⅓ of that of the third light-emitting unit3. In another embodiment, when the sizes of the light-emitting units are similar to each other/the same, the ratio of the luminous efficiency of the first light-emitting unit1to the second light-emitting unit2is less than ¼, the ratio of the luminous efficiency of the first light-emitting unit1to the third light-emitting unit3is less than ⅓. When the sizes of the light-emitting units are miniaturized and are similar (or identical) to each other, the luminous efficiency/luminance of the red light-emitting unit is lower than that of the green light-emitting unit and that of the blue light-emitting units. In order to balance the luminance of the red, blue, and green lights of the light-emitting device, it is necessary to increase the light-emitting area of the red light-emitting unit for increasing the amount of red light.

FIG.2shows a light-emitting device200. The light-emitting device200can emit a white light. The amount of the red light-emitting units is more than that of the blue light-emitting unit and that of the green light-emitting unit. Therefore, the light-emitting area of the red light is larger than that of the blue light, and the light-emitting area of the red light is larger than that of the green light. The red light emitted from the light-emitting device200has a first brightness, the green light emitted from the light-emitting device200has a second brightness, and the ratio of the first brightness to the second brightness is between 0.8 and 1.2. In this embodiment, the light-emitting device200includes two light-emitting units, a first light-emitting unit1and a fourth light-emitting unit5, which can emit red lights, a second light-emitting unit2which can emit a blue light, and a third light-emitting unit3which can emit a green light, and a supporting body4. The light-emitting units1,2,3, and5are disposed on the upper surface of the supporting body4, and the light-emitting surfaces of the light-emitting units1,2,3, and5have the same normal direction which is the same as a normal direction of the upper surface of the supporting body4. Each of the lengths and widths of the light-emitting units1,2,3, and5is less than 100 μm, or each of the areas of the light-emitting areas (projected area of the active stack) of the light-emitting units1,2,3, and5is less than 0.01 mm2. In one embodiment, each of the light-emitting units has a rectangular shape with a length and a width of less than 70 μm, such as a rectangle with a length of 30 μm and a width of 50 μm. In another embodiment, each of the areas of the light-emitting areas of the light-emitting units1,2,3,5(the projected area of the active stack) is less than 2500 μm2. For example, the light-emitting unit has a circle shape with a radius of about 22 μm. Some or all of the light-emitting units1,2,3, and5can be electrically connected to the supporting body4by flip bonding and/or wire bonding. The size of the light-emitting device200is less than 1 mm×1 mm. In one embodiment, the size of the light-emitting device200is between 0.1 mm×0.1 mm and 1 mm×1 mm. The shape of the light-emitting unit can be a rectangle, a circle, a triangle, a square, a parallelogram, a trapezoid, or other polygonal shapes. The shape of the light-emitting unit is an exemplary here and is not a limitation of the disclosure. In an embodiment, each of the light-emitting units has a rectangular shape. In another embodiment, the shape of each of the light-emitting units can be the same, different, or some can be the same and some are different. In another embodiment, the number of red light-emitting units is greater than 2, the number of green light-emitting units is at least 1, and the number of blue light-emitting units is at least 1, but the number of red light-emitting units is more than that of green light-emitting unit, and is also more than that of blue light-emitting unit. The materials of the light-emitting units and the supporting body can be referred to the aforementioned descriptions.

In the aforementioned embodiment, in order to make the brightness of the three colors to be balanced, the light-emitting area of the red light is increased by increasing the number of red light-emitting units, so that the number of red light-emitting units is greater than that of the green light-emitting units and that of the blue light-emitting units. In addition to adjusting the number of red light-emitting units, it is also possible to use a red light-emitting unit which has a larger size along with a blue light-emitting unit and a green-emitting unit which have a smaller size. As shown inFIG.3, the light-emitting device300can emit a white light, the light-emitting area of the red light-emitting unit is larger than that of the blue light-emitting unit, and the light-emitting area of the red light-emitting unit is larger than that of the green light-emitting unit. The light-emitting device300can emit a red light having a first brightness, a green light having a second brightness, and the ratio of the first brightness to the second brightness is between 0.8 and 1.2. The light-emitting device300includes a first light-emitting unit1that emits a red light, a second light-emitting unit2that emits a blue light, a third light-emitting unit3that emits a green light, and a supporting body4. Each of the lengths and the widths of the light-emitting units1,2, and3is less than 100 μm, or each of the sizes (projected area of the active stack) of the light-emitting units1,2, and3is less than 0.01 mm2. The size of the first light-emitting unit1is larger than that of the second light-emitting unit2and is also larger than that of the third light-emitting unit3. In other words, the light-emitting area of the first light-emitting unit1is larger than that of the second light-emitting unit2and is also larger than that of the third light-emitting unit3. In an embodiment, the area of the first light-emitting unit1is at least 1.5 times of that of the second light-emitting unit2, for example, 1.5 to 20 times. The area of the first light-emitting unit1is at least 1.5 times of that of the third light-emitting unit3, for example, 1.5 to 20 times. In another embodiment, the area of the first light-emitting unit1is at least 2 times of that of the second light-emitting unit2, and the area of the first light-emitting unit1is at least 2 times of that of the third light-emitting unit3. In another embodiment, each of the second and third light-emitting units2,3has a length and a width of less than 70 μm, such as the light-emitting unit has a rectangular shape with a length of 30 μm and a width of 50 μm. In another embodiment, each of the sizes of the light-emitting units1,2,3,5(the projected area of the active stack) is less than 2500 μm2. For example, the light-emitting unit has a circle shape with a radius of about 22 μm. The size of the light-emitting device300is less than 1 mm×1 mm. In one embodiment, the size of the light-emitting device300is between 0.1 mm×0.1 mm and 1 mm×1 mm. The shape of the light-emitting unit can be a rectangle, a circle, a triangle, a square, a parallelogram, a trapezoid, or other polygonal shapes. The shape of the light-emitting unit is an exemplary here and is not a limitation of the disclosure. In an embodiment, each of the light-emitting units has a rectangular shape. In another embodiment, the shape of each of the light-emitting units can be different, or some can be the same and some are different. Some or all of the light-emitting units1,2, and3can be electrically connected to the supporting body4by flip bonding and/or wire bonding. The materials of the light-emitting units1,2,3, and the supporting body4can be referred to the aforementioned descriptions.

The light-emitting device of the aforementioned embodiment, the light-emitting units1,2, and3are arranged along a horizontal direction on the upper surface of the supporting body4(the arrangement direction is perpendicular to the normal direction of the upper surface of the supporting body4), therefore, in the top view, the total area of the light-emitting device is greater than/or equal to the summation of the areas of the first light-emitting unit1, the second light-emitting unit2, and the third light-emitting unit3. In order to reduce the size, vertical arrangement can be used to make the total area of the light-emitting device smaller than the summation of the areas of the light-emitting units.FIG.4Ashows a light-emitting device401, which can emit a white light. The light-emitting device401includes a first light-emitting unit1which can emit a red light, a second light-emitting unit2which can emit a blue light, and a third light-emitting unit3which can emit a green light, and a supporting body (not shown). The light-emitting surfaces of the light-emitting units1,2, and3have the same normal direction. Each of the lengths and the widths of the light-emitting units1,2, and3is less than 100 μm, or each of the sizes (projected area of the active stack) of the light-emitting units1,2,3is less than 0.01 mm2. The size of the first light-emitting unit1is larger than that of the second light-emitting unit2and is also larger than that of the third light-emitting unit3. The third light-emitting unit3is disposed on the first light-emitting unit1and covers a portion of the light-emitting surface of the first light-emitting unit1. The second light-emitting unit2is disposed on the third light-emitting unit3and covers a portion of the light-emitting surface of the third light-emitting unit3. In the top view, the second light-emitting unit2fully overlaps the third light-emitting unit3, and the outer side of the second light-emitting unit2is surrounded by a portion of the light-emitting surface of the third light-emitting unit3. The second light-emitting unit2and the third light-emitting unit3fully overlap the first light-emitting unit1, and the outer side of the third light-emitting unit3is surrounded by a portion of the light-emitting surface of the first light-emitting unit1. In an embodiment, the light emitted from the first light-emitting unit1can penetrate the second light-emitting unit2and the third light-emitting unit3, and the light emitted from the third light-emitting unit3can penetrate the second light-emitting unit2. The area of the first light-emitting unit1is larger than that of the third light-emitting unit3, and larger than that of the second light-emitting unit2. For example, the area of the first light-emitting unit1is at least 1.5 times of that of the second light-emitting unit2, for example, 1.5 to 20 times. The area of the first light-emitting unit1is at least 1.5 times of that of the third light-emitting unit3, for example, 1.5 to 20 times. In another embodiment, the second light-emitting unit2and the third light-emitting unit3comprise a reflective layer, so that the light of the light-emitting unit2and the light-emitting unit3are reflected by the reflective layer and are emitted upward to increase the brightness. Therefore, the light emitted from the first light-emitting unit1does not penetrate the second light-emitting unit2and the third light-emitting unit3, and the light emitted from the second light-emitting unit2does not penetrate the third light-emitting unit3. The uncovered light-emitting area of the first light-emitting unit1is larger than that of the third light-emitting unit3, and is larger than the light-emitting area of the second light-emitting unit2. For example, the uncovered light-emitting area of the first light-emitting unit1is at least 1.5 times of light-emitting area of the second light-emitting unit2, for example, 1.5 to 20 times. The uncovered light-emitting area of the first light-emitting unit1is at least 1.5 times of that of the third light-emitting unit3, for example, 1.5 to 20 times. In one embodiment, each of the lengths and the widths of the second and third light-emitting units is less than 70 μm. For example, the second and third light-emitting units have rectangular shapes with a length of 30 μm and a width of 50 μm. In another embodiment, each of the sizes of the light-emitting units1,2,3(the projected area of the active stack) is less than 2500 μm2. For example, the light-emitting unit has a circle shape with a radius of about 22 μm. In the top view, the first light-emitting unit1, the second light-emitting unit2, and the third light-emitting unit3have the same geometric center. In another embodiment, in the top view, the geometric centers of the first light-emitting unit1, the second light-emitting unit2, and the third light-emitting unit are different. In another embodiment, as shown inFIG.4B, in the light-emitting device402, the first light-emitting unit1can emit a red light, the second light-emitting unit2can emit a blue light, and the third light-emitting unit3can emit a green light. The second light-emitting unit2is disposed on the first light-emitting unit1, and covers a portion of the first light-emitting unit1, and the third light-emitting unit3is disposed on the second light-emitting unit2, and covers a light-emitting surface of the second light-emitting unit2.

The light-emitting units1,2, and3are joined by a bonding material, and the bonding material can include glue. The glue can be polyimide, benzocyclobutene (BCB), perfluorocyclobutane (PFCB), epoxy, Su8, or spin-on glass (SOG). In another embodiment, there is no bonding material between the light-emitting units1,2and between the light-emitting units2,3. After the light-emitting units1,2, and3are disposed on the supporting body, a glue material covers the light-emitting units1,2, and3to protect the light-emitting units1,2, and3. The material of the glue can refer to the aforementioned bonding material. The light-emitting units1,2,3can be electrically connected to an external power source by flip bonding or wire bonding. In one embodiment, the first light-emitting unit1is electrically connected to an external power source by flip bonding, and the second light-emitting unit2and the third light-emitting unit3are electrically connected to an external power source by wire bonding. In another embodiment, the first light-emitting unit1, the second light-emitting unit2, and the third light-emitting unit3are electrically connected to an external power source by wire bonding. The shape of the light-emitting unit can be a rectangle, a circle, a triangle, a square, a parallelogram, a trapezoid, or other polygonal shapes. The shape of the light-emitting unit is an exemplary here and is not a limitation of the disclosure. In an embodiment, each of the light-emitting units has a rectangular shape. In another embodiment, the shape of each of the light-emitting units can be different, or some can be the same and some are different. The supporting body (not shown) is located under the first light-emitting unit1and can be slightly larger than the first light-emitting unit1. In the top view, the total area of the light-emitting device401is smaller than summation of the areas of the first light-emitting unit1, the second light-emitting unit2, and the third light-emitting unit3. In another embodiment, in a top view, the supporting body (not shown) is equal to or slightly smaller than the first light-emitting unit1, and then the area of the light-emitting device401is equal to that of the first light-emitting unit1.

In another embodiment, in order to reduce the size of the light-emitting device in a top view, and also to reduce the thickness of the light-emitting device in a side view, some of the light-emitting units can be arranged along a vertical direction and some of the light-emitting units can be arranged along a horizontal direction. As shown inFIG.5, the light-emitting device500which can emit a white light, and includes a first light-emitting unit1which can emit a red light, a second light-emitting unit2which can emit a blue light, and a third light-emitting unit3which can emit a green light. The light-emitting surfaces of the light-emitting units1,2, and3have the same normal direction. Each of the lengths and the widths of the light-emitting units1,2, and3is less than 100 μm, or each of the sizes (projected area of the active stack) of the light-emitting units is less than 0.01 mm2. The size of the first light-emitting unit1is larger than that of the second light-emitting unit2, and is also larger than that of the third light-emitting unit3. The second light-emitting unit2is disposed on the first light-emitting unit1and covers a first portion of the light-emitting surface of the first light-emitting unit1. The third light-emitting unit3is disposed on the first light-emitting unit1and covers the second portion of the light-emitting surface of the first light-emitting unit1. The second portion is different from the first portion. In a top view, the second light-emitting unit2is physically separated from the third light-emitting unit3and fully overlaps the first light-emitting unit1, the outer side of the second light-emitting unit2is surrounded by a portion of the light-emitting surface of first light-emitting unit1. The second light-emitting unit2and the first light-emitting unit1are arranged along a vertical direction (the arrangement direction is parallel to the normal direction of the light-emitting surface of the first light-emitting unit1), the third light-emitting unit3and the first light-emitting unit1are arranged along a vertical direction (the arrangement direction is parallel to the normal direction of the light-emitting surface of the first light-emitting unit1), and the second light-emitting unit2and the third light-emitting unit3are disposed on the first light-emitting unit1so the arrangement direction is perpendicular to the normal direction of the light-emitting surface of the first light-emitting unit1. In an embodiment, the light emitted from the first light-emitting unit1can penetrate the second light-emitting unit2and the third light-emitting unit3, and the light-emitting area of the first light-emitting unit1is larger than that of the third light-emitting unit3and larger than that of the second light-emitting units2. For example, the light-emitting area of the first light-emitting unit1is at least 1.5 times of that of the second light-emitting unit2, for example, 1.5 to 20 times. The area of the first light-emitting unit1is at least 1.5 times of that of the third light-emitting unit3, for example, 1.5 to 20 times. In another embodiment, the second light-emitting unit and the third light-emitting unit include a reflective layer, so that the light emitted from the light-emitting layer of the light-emitting units2,3is reflected by the reflective layer and is emitted upward to increase the brightness. Therefore, the light emitted from the first light-emitting unit1does not penetrate the second light-emitting unit2and the third light-emitting unit3. The uncovered light-emitting area of the first light-emitting unit1is larger than the light-emitting area of the second light-emitting unit2and the light-emitting area of the third light-emitting unit3. For example, the uncovered light-emitting area of the first light-emitting unit1is at least 1.5 times of the area of the second light-emitting unit, for example, 1.5 to 20 times. The uncovered light-emitting area of the first light-emitting unit1is at least 1.5 times of the area of the second light-emitting unit2, for example, 1.5 to 20 times. In one embodiment, each of the length and the width of the light-emitting unit is less than 70 μm. For example, the light-emitting unit has a rectangular shape with a length of 30 μm and a width of 50 μm. In another embodiment, each of the sizes of the light-emitting units1,2,3(the projected area of the active stack) is less than 2500 μm2. For example, the light-emitting unit has a circle shape with a radius of about 22 μm. In a top view ofFIG.5, the locations of the second light-emitting unit2and the third light-emitting unit3are close to two opposite diagonal ends of the light-emitting surface of the first light-emitting unit1, and a distance between the geometric centers of the second light-emitting unit2and the first light-emitting unit1are substantially the same as that between the geometric centers of the second light-emitting unit3and the first light-emitting unit1. In another embodiment, the common geometric center of the second light-emitting unit2and the third light-emitting unit3is different from the geometric center of the first light-emitting unit1in the top view.

The light-emitting units2,3and the light-emitting unit1are joined by a bonding material, and the bonding material can include glue. The glue can be polyimide, benzocyclobutene (BCB), perfluorocyclobutane (PFCB), epoxy, Su8, or spin-on glass (SOG). In another embodiment, there is no bonding material between the light-emitting units1,2and between the light-emitting units2,3. After the light-emitting units1,2, and3are disposed on the supporting body, a glue material covers the light-emitting units1,2, and3to protect the light-emitting units1,2, and3. The material of the glue can be the aforementioned bonding material. The light-emitting units1,2, and3can be electrically connected to an external power source by flip bonding or wire bonding. In one embodiment, the first light-emitting unit1is electrically connected to an external power source by flip bonding, and the second light-emitting unit2and the third light-emitting unit3are electrically connected to an external power source by wire bonding. In another embodiment, the first light-emitting unit1, the second light-emitting unit2, and the third light-emitting unit3are electrically connected to an external power source by wire bonding. The shape of the light-emitting unit can be a rectangle, a circle, a triangle, a square, a parallelogram, a trapezoid, or other polygonal shapes. The shape of the light-emitting unit is an exemplary here and is not a limitation of the disclosure. In an embodiment, each of the light-emitting units has a rectangular shape. In another embodiment, the shape of each of the light-emitting units can be different, or some can be the same and some are different.

In another embodiment, all of the light-emitting units1,2,3are flip chips and are bonded to the supporting body by flip bonding.FIG.6shows a light-emitting device600which can emit a white light, and includes a first light-emitting unit1which can emit a red light, a second light-emitting unit2which can emit a blue light, and a third light-emitting unit3which can emit a green light, and a supporting body4which the first light-emitting unit1, the second light-emitting unit2, and the third light-emitting unit3are disposed on. The light-emitting surfaces of the light-emitting units1,2, and3have the same normal direction. Each of the lengths and widths of the light-emitting units1,2, and3is less than 100 μm, or each of the sizes (projected area of the active stack) of the light-emitting units is less than 0.01 mm2. The size of the first light-emitting unit1is larger than that of the second light-emitting unit2, and is also larger than that of the third light-emitting unit3. The second light-emitting unit2is disposed on the first light-emitting unit1and covers a first portion11of the light-emitting surface of the first light-emitting unit1. The third light-emitting unit3and the second light-emitting unit2are arranged along a horizontal direction on the first light-emitting unit1. The third light-emitting unit3is disposed on the first light-emitting unit1and covers the second portion12of the light-emitting surface of the first light-emitting unit1. The second portion12is different from the first portion11. In the top view, the second light-emitting unit2is physically separated from the third light-emitting unit3. The second light-emitting unit2partially overlaps the first light-emitting unit1. The longitudinal direction of the second light-emitting unit2is perpendicular to the longitudinal direction of the first light-emitting unit1. The third light-emitting unit3partially overlaps the first light-emitting unit1. The longitudinal direction of the third light-emitting unit3is perpendicular to the longitudinal direction of the first light-emitting unit1. The second light-emitting unit2and the first light-emitting unit1are arranged along a vertical direction (the arrangement direction is parallel to the normal direction of the light-emitting surface of the first light-emitting unit1). The third light-emitting unit3and the first light-emitting unit1are arranged along a vertical direction (the arrangement direction is parallel to the normal direction of the light-emitting surface of the first light-emitting unit1). The second light-emitting unit2and the third light-emitting unit3are disposed on the first light-emitting unit1so the arrangement direction is perpendicular to the normal direction of the light-emitting surface of the first light-emitting unit1. In order to facilitate the stacking of the second light-emitting unit2and the third light-emitting unit3on the first light-emitting unit1, the first light-emitting unit1does not have a growth substrate or has a thinned growth substrate, so that the thickness of the first light-emitting unit1is thinner than that of the second light-emitting unit2and that of the third light-emitting unit3. In another embodiment, in order to reduce the thickness of the light-emitting device, the light-emitting units1,2, and3do not have the growth substrate or have a thinned growth substrate.

The light-emitting units2,3and the light-emitting unit1are joined by a bonding material, and the bonding material can include glue. The glue can be polyimide, benzocyclobutene (BCB), perfluorocyclobutane (PFCB), epoxy, Su8, or spin-on glass (SOG). In another embodiment, there is no bonding material between the light-emitting units1,2and between the light-emitting units1,3. After the light-emitting units1,2, and3are disposed on the supporting body4, a glue material covers the light-emitting units1,2, and3to protect the light-emitting units1,2, and3. In detail, the glue can continuously cover the outer side surfaces and the light-emitting surfaces of the light-emitting units1,2, and3. The material of the glue can refer to aforementioned description.

As shown inFIG.6, in a top view, the second light-emitting unit2includes a first portion21which overlaps the first light-emitting unit1, a second portion22and a third portion23which do not overlap the first light-emitting unit1. The second portion22and the third portion23are located on opposite sides of the first portion21. The second portion22is located outside the front side16of the first light-emitting unit1, and the third portion23is located outside the rear side17opposite to the front side16of the first light-emitting unit1. The first portion21is located between the front side16and the rear side17of the first light-emitting unit1. The third light-emitting unit3includes a first portion31overlapping the first light-emitting unit1, a second portion32and a third portion33which do not overlap the first light-emitting unit1. The second portion32and the third portion33are located at opposite sides of the first portion31. The second portion32is located outside the front side16of the first light-emitting unit1, and the third portion33is located outside the rear side17opposite to the front side16of the first light-emitting unit1. The first portion31is located between the front side16and the rear side17of the first light-emitting unit1. The first light-emitting unit1has a first portion11covered by the second light-emitting unit2, a second portion12covered by the third light-emitting unit3, and a third portion13, a fourth portion14, and a fifth portion15which are not covered by the second light-emitting unit2and the third light-emitting unit3. The third portion13of the light-emitting surface of the first light-emitting unit1is located between the second light-emitting unit2and the third light-emitting unit3. The fourth portion14of the light-emitting surface of the first light-emitting unit1is located on the left side of the first light-emitting unit1and outside the left side of the second light-emitting unit2. The fifth portion15of the light-emitting surface of the first light-emitting unit1is located on the right side of the first light-emitting unit1and outside the right side of the third light-emitting unit3. The light-emitting area (the summation of the areas of the third portion13, the fourth portion14, and the fifth portion15) that are not been covered of the first light-emitting unit1is larger than the light-emitting area of the second light-emitting unit2(the summation of the areas of the first portion21, the second portion22, and the third portion23), and is also larger than the light-emitting area of the third light-emitting unit3(the summation of the first portion31, the second portion32, and the third portion33). In an embodiment, the light emitted from the first light-emitting unit1can penetrate the second light-emitting unit2and the third light-emitting unit3, and the area of the first light-emitting unit1is larger than that of the third light-emitting unit3, and larger than that of the second light-emitting unit2. For example, the light-emitting area of the first light-emitting unit1is at least 1.5 times of that of the second light-emitting unit2, for example, 1.5 to 20 times. The area of the first light-emitting unit1is at least 1.5 times of that of the third light-emitting unit3, for example, 1.5 to 20 times. In another embodiment, the light emitted from the first light-emitting unit1does not penetrate the second light-emitting unit2and the third light-emitting unit3, and the uncovered light-emitting area of the first light-emitting unit1is at least 1.5 times of the light-emitting area of the second light-emitting unit2, for example, 1.5 to 20 times. In one embodiment, each of the lengths and the widths of the second and third light-emitting units is less than 70 μm, such as the second and third light-emitting units have rectangular shape with a length of 30 μm and a width of 50 μm. The electrode pads of the light-emitting units1,2, and3are disposed on the bottom surface corresponding to the light-emitting surfaces of each of the light-emitting units, and are electrically connected to the supporting body4by flip bonding.

In another embodiment, the light-emitting units2,3can be partially located at the leftmost or rightmost side of the first light-emitting unit1, thus the first light-emitting unit1has at least one uncovered light-emitting area. For example, the second light-emitting unit2is located at the leftmost side of the first light-emitting unit1, the third light-emitting unit3is located at the rightmost side of the first light-emitting unit1and physically separated from the second light-emitting unit2, and then the first light-emitting unit1has one uncovered light-emitting area. In another embodiment, the light-emitting units2,3can be arranged side by side and disposed on the first light-emitting unit1, so that the first light-emitting unit1has at least one uncovered light-emitting area. For example, the light-emitting units2,3are located between the leftmost side and the rightmost side of the first light-emitting unit1, and the second light-emitting unit2and the third light-emitting unit3are arranged along a horizontal direction on the light-emitting unit1and adjacent to each other without a gap therebetween. Therefore, the first light-emitting unit1has two separated and uncovered light-emitting areas.

FIGS.7A to7Eshow steps of manufacturing a light-emitting device600in accordance with an embodiment of the present disclosure. As shown inFIG.7A, a supporting body4is provided. The supporting body4has a first group of bonding pads61,62, a second group of pads63,64, a third group of pads65,66, and optionally has a conductive structure (not shown) for electrically connecting the light-emitting units. The first group of pads61,62corresponds to the electrode pads of the first light-emitting unit1, the second group of pads63,64corresponds to the electrode pads of the second light-emitting unit2, and the third group of pads65,66corresponds to the third light-emitting unit3electrodes. As shown inFIG.7B, a paste71is formed on the first group of pads61,62. The paste71includes an insulating material and a plurality of conductive particles dispersed in the insulating material. The method of forming the paste can be the patterning jig, such as a stencil, such that the paste71does not cover the second group of pads63,64and the third group of pads65,66. In an embodiment, the pads61and the pads62separated from each other are covered by the same paste71. In another embodiment, the pads61and pads62separated from each other are covered by two physically separated pastes. As shown inFIG.7C, the first light-emitting unit1which is a flip chip is placed on the corresponding first group of pads61,62and is in contact with the paste71. Then, a thermal curing step is performed to bond the first light-emitting unit1with the first group of pads61,62. As shown inFIG.7D, the paste72is formed on the pads63and65which are outside the front side16of the first light-emitting unit1, wherein the pads63and65respectively belong to the second group of pads and the third group of pads. The paste73is on the pads64and66which are outside the rear side17of the first light-emitting unit1, wherein the pads64and66respectively belong to the second group of pads and the third group of pads. The method of forming the paste can be the patterning jig, such that the paste72does not cover the first light-emitting unit1and the pads64,66, and the paste73does not cover the first light-emitting unit1and the pads63,65. In one embodiment, the pads63and65separated from each other are covered by the same paste72, and the pads64and pads66separated from each other are covered by the same paste73. In another embodiment, the pads63,64,65,66separated from each other are covered by four physically separated pastes. As shown inFIG.7E, the second light-emitting unit2which is a flip chip is placed on the corresponding second group of pads63,64and is in contact with the pastes72and73. The third light-emitting unit3which is a flip chip is placed on the corresponding third group of pads65,66and is in contact with the pastes72and73. Then, a thermal curing step is performed to bond the second light-emitting unit2with the second group of pads63,64, and bond the third light-emitting unit3with the third group of pads65,66to complete the fabrication of the light-emitting device.

FIGS.8A˜8B show steps of bonding the light-emitting units shown inFIGS.7A˜7E to a supporting body.FIG.8Ashows the structure before thermal curing, andFIG.8Bshows the structure after thermal curing. Taking the first light-emitting unit1as an example, as shown inFIG.8A, the first light-emitting unit1includes two electrode pads181,182disposed on a bottom surface112corresponding to the light-emitting surface111. The electrode pads181,182respectively face the first group of pads61,62on the supporting body4, and the paste71is disposed between the first light-emitting unit1and the supporting body4. As shown inFIG.8A, before thermal curing, the paste71includes an insulating material74and a plurality of conductive particles75dispersed in the insulating material74. The method of bonding the first light-emitting unit1includes a thermal curing. During the curing process, the viscosity of the insulating material74is first decreased and then raised, and the conductive particles75are gathered in a region which is between or around the electrode pads181,182of the first light-emitting unit and the first group of pads61,62.FIG.8Bshows the state after thermal curing. As shown inFIG.8B, after the thermal curing, most of the conductive particles75are concentrated and formed a conductive structure78which is between the electrode pads181,182of the first light-emitting unit and the first group of pads61,62. The insulating material74forms a non-conductive structure77surrounding the conductive structure78. A few of the conductive particles75disperses in the non-conductive structure77. The average density of the conductive particles75in the conductive structure78is larger than that in the non-conductive region77. In an embodiment, the conductive structure78does not have the insulating material74.

The conductive particles75can include a metal with a low melting temperature of less than 210° C., or an alloy with low liquidus melting temperature of less than 210° C. The metal can be an element, a compound, or an alloy, such as Bi, Sn, Ag, In, or an alloy thereof. In one embodiment, the metal has a low melting temperature of less than 170° C. or the alloy has a liquidus melting temperature of less than 170° C. The material of the alloy with the low liquidus melting temperature can be a Sn—In alloy or a Sn—Bi alloy. The insulating material74can be a thermosetting polymer such as epoxy, silicone, polymethyl methacrylate, and episulfide. The insulating material74can be cured at a curing temperature. In an embodiment, the melting temperature of the conductive particles75is lower than the curing temperature of the insulating material74. Before the thermal curing,FIG.8Ashows the particle size of the conductive particles75is defined as the diameter of the conductive particles75, which is between 5 μm and 50 μm. The shortest distance between the two electrode pads181,182is preferably more than twice of the particle size of the conductive particles75. If the first light-emitting unit1is a rectangular shape with a size of less than 100 μm×100 μm, for example, 80 μm×80 μm, or 70 μm×50 μm, the shortest distance between the two electrode pads181,182of the first light-emitting unit1is preferably not more than 50 μm, for example: no more than 40 μm, 30 μm, or 20 μm.

After thermal curing,FIG.8Bshows the conductive particles75are aggregated into a bulk and be a conductive structure78. The conductive structure78covers at least one side surface of the electrode pads181,182, and the pads61,62. The conductive structure78directly contacts the corresponding electrode pads181,182and pads61,62to provide electrical conduction. The external power can drive the light-emitting unit1through the pads61,62, the conductive structure78, the electrode pads181,182. The insulating structure77surrounds the outer surfaces of the conductive structure78, the electrode pads181,182, the pads61,62. The conductive particles75in the non-conductive region77are distributed discretely and surrounded by the insulating material74. Therefore, the conducting current cannot pass through the non-conductive region77. The non-conductive region77can enhance the bonding strength between the light-emitting unit1and the supporting body4and avoid the conductive material from oxidation due to contacting the external environment, and also can prevent the conductive structure78from softening or melting due to high temperature environment that may cause a short circuit problem. In a cross-sectional view, taking the corresponding electrode pad182and the pad62as an example, the bottom end of the conductive structure78(the end contacting the pad62) completely covers the top surface624of the pad62, and the top end of the conductive structure78(the end contacting the electrode pad182) completely covers the bottom surface183of the electrode pad182. The conductive structure78has a necking shape, and the outer side surface781of the conductive structure78has a surface with a concave portion and a convex portion. In detail, the electrode pad182has a width W1, the pad62has a width W2, and the width W2of the pad62is larger than or equal to the width W1of the electrode pad182. The conductive structure78has a width W3that is not a constant value along the normal direction of the supporting body4. The conductive structure78has a minimum width W3(min) at the necking portion between the electrode pad182and the pad62. The minimum width W3(min) of the conductive structure78is smaller than the width W1of the electrode pad182or/and the width W2of the pad62. In another embodiment, the outer side surface781of the conductive structure78is a convex arc shape so the conductive structure78does not have the necking portion. In another embodiment, the outer side surface781of the conductive structure78is a flat surface.

As shown inFIG.8B, the outermost surface711of the paste71has a curved shape and extends from the supporting body4to the outer side surface19of the light-emitting unit1. The shape of the paste71changes after thermal curing (compared toFIG.8A), that is, the paste71has a different shape before and after the thermal curing. The paste71covers a portion of the outer side surface19of the light-emitting unit1. More specifically, after thermal curing, as shown inFIG.8B, the outermost surface711of the paste71has an angle θ with respect to the supporting body4, and the angle θ gradually increases along the direction of the outermost surface711toward the outer side surface19of the light-emitting unit1.

FIG.9is a view of a display module1000according to an embodiment of the present disclosure. The display module1000includes a substrate8, such as a circuit substrate, and a plurality of light-emitting devices700. The plurality of light-emitting devices700can be the aforementioned light-emitting devices100,200,300,401,402,500,600, or a combination thereof. In one embodiment, the plurality of light-emitting devices700is arranged in an array on the substrate8and electrically connected to a circuit (not shown) on the substrate8. The surface of the substrate8can have a light-absorbing layer (not shown) to improve the contrast of the display module1000when displaying. The light-absorbing material is preferably the light-blocking material which does not reflect light and has dark color, such as black, brown, or gray. The light-blocking material is a dark and opaque material. The opaque material can include bismaleimide triazine resin (BT) which is light yellow, and a surface of the BT is covered by a material that can block visible light, such as black ink, or a light-shielding material. The light-shielding material can include metal, resin, or graphite. The metal can be chromium. The resin can include polyimide (PI) or acrylate, and a material which can absorb light, such as carbon, titanium oxide or the like, or a dark pigment, dispersed in the resin.

FIG.10is a view of a display device2000in accordance with an embodiment of the present disclosure. The display device2000includes a carrier substrate91. The plurality of display modules1000are formed on the carrier substrate91. A frame92surrounds the plurality of display modules1000, and a plate93covers the display module1000and the frame92. In an embodiment, the spacing between adjacent display modules1000can be very small, even two adjacent display modules adjoin with each other (the spacing is zero).

FIG.11is a display system3000in accordance with an embodiment of the present disclosure. The display system3000includes a processor301, a data receiver302, a display device303, and one or more display driver ICs304. The data receiver302can receive data by the wireless communication or by the wired communication. The method of the wireless communication can adopt any wireless standard or protocol, for example: WiFi (IEEE802.11), WiMAX (IEEE 802.16), IEEE 802.20, LTE, Ev_D0, HSPA+, HSDPA+, HSUPA+, EDGE, GSM, GPRS, CDMA, TDMA, EDCT, Bluetooth, or any wireless protocol designated as 3G, 4G, 5G and higher generation. One or more display driver ICs304are electrically coupled to display device303. The display device303includes aforementioned display device2000, the display module1000, or the light-emitting devices100˜600. Depending on the application, display system3000can optionally include other components, such as memory components, touch screen controllers, sensors, and batteries.

FIG.12Ashows a top view of the light-emitting device601. The light-emitting device601is similar to the light-emitting device600ofFIG.6and includes a first light-emitting unit1, a second light-emitting unit2, and a third light-emitting unit3. The light-emitting surfaces of the light-emitting units1,2, and3have the same normal direction, and towards the direction corresponding to the supporting body4. The electrode pads of the light-emitting units1,2, and3are located at two opposite ends of the bottom surface corresponding to the light-emitting surface, and are electrically connected to the supporting body4by flip bonding. The second light-emitting unit2is physically separated from the third light-emitting unit3. The second light-emitting unit2and the third light-emitting unit3are arranged along a horizontal direction on the light-emitting unit1and cover a portion of the first light-emitting unit1. The longitudinal direction of the second light-emitting unit2is perpendicular to the longitudinal direction of the first light-emitting unit1, and partially overlaps the first light-emitting unit1. The longitudinal direction of the third light-emitting unit3is perpendicular to the longitudinal direction of the first light-emitting unit1, and partially overlaps the first light-emitting unit1. The first light-emitting unit1is bonded to the supporting body4by a paste71. The electrode pads of the second light-emitting unit2and the third light-emitting unit3located on the left side of the first light-emitting unit1are bonded to the supporting body4by a single, non-separating paste72. The electrode pads of the second light-emitting unit2and the third light-emitting unit3located on the right side of the first light-emitting unit1are bonded to the supporting body4by a bulk, non-separated paste73. The materials of the pastes71,72, and73and forming methods of can be referred to the aforementioned related descriptions ofFIGS.7and8. Each of the lengths of the light-emitting units1,2,3is larger than 100 μm, each of the widths of the light-emitting units1,2,3is larger than 50 μm, or each of the sizes (projected area of the active stack) of the light-emitting units1,2,3is larger than 0.005 mm2. The first light-emitting unit1emits a red light, the second light-emitting unit2emits a blue light, and the third light-emitting unit3emits a green light. In an embodiment, the light emitted from the first light-emitting unit1can penetrate the second light-emitting unit2and the third light-emitting unit3, and the area of the first light-emitting unit1is larger than that of the third light-emitting unit3and larger than that of the second light-emitting units2. In another embodiment, the second light-emitting unit and the third light-emitting unit include a reflective layer, so that the light emitted from the light-emitting layer of the light-emitting units is reflected by the reflective layer and is emitted upward to increase the brightness. Therefore, the light emitted from the first light-emitting unit1does not penetrate the second light-emitting unit2and the third light-emitting unit3. In order to facilitate the stacking of the second light-emitting unit2and the third light-emitting unit3on the first light-emitting unit1, the first light-emitting unit1does not have a growth substrate or has a thinned growth substrate, so that the thickness of the first light-emitting unit1is thinner than that of the second light-emitting unit2and that of the third light-emitting unit3. In another embodiment, in order to reduce the thickness of the light-emitting device, the light-emitting units1,2, and3do not have the growth substrate or have a thinned growth substrate.

The light-emitting units2,3and the light-emitting unit1are joined by a bonding material, and the bonding material can be referred to aforementioned descriptions ofFIG.6. In another embodiment, there is no bonding material between the light-emitting units1,2, and the light-emitting units1,3. After the light-emitting units1,2, and3are disposed on the supporting body4, a glue material covers the light-emitting units1,2, and3to protect the light-emitting units1,2, and3. The material of the glue can refer to aforementioned description.

FIG.12Bshows a top view of the light-emitting device602. The light-emitting device602includes a first light-emitting unit1, a second light-emitting unit2, and a third light-emitting unit3. All of the electrode pads of the light-emitting units1,2, and3are disposed on the bottom surface corresponding to the light-emitting surface, and are electrically connected to the supporting body4by flip bonding. The arrangements of the first light-emitting unit1, the second light-emitting unit2, and the third light-emitting unit3can be referred to the related descriptions ofFIG.12A. The first light-emitting unit1is bonded to the supporting body4by a paste71. Two ends of the second light-emitting unit2are bonded to the supporting body4by pastes72,73. Two ends of the third light-emitting unit3are bonded to the supporting body4by pastes74,75. The light-emitting device601has some differences fromFIG.12A, the electrode pads of the second light-emitting unit2and the third light-emitting unit3located on the left side of the first light-emitting unit1are bonded to the supporting body4by two physically separated pastes72,74. The electrode pads of the second light-emitting unit2and the third light-emitting unit3located on the right side of the first light-emitting unit1are bonded to the supporting body4by two physically separated pastes73and75. Each of the lengths of the light-emitting units1,2,3is larger than 100 μm, each of the widths of the light-emitting units1,2,3is larger than 50 μm, or each of the sizes (projected area of the active stack) of the light-emitting units1,2,3is larger than 0.005 mm2. The first light-emitting unit1emits a red light, the second light-emitting unit2emits a blue light, and the third light-emitting unit3emits a green light. In an embodiment, the light emitted from the first light-emitting unit1can penetrate the second light-emitting unit2and the third light-emitting unit3. The area of the first light-emitting unit1is larger than that of the third light-emitting unit3and larger than that of the second light-emitting units2. In another embodiment, the light emitted from the first light-emitting unit1does not penetrate the second light-emitting unit2and the third light-emitting unit3.

FIG.12Cshows a display module1001. The display module1001includes a substrate8, such as a circuit substrate, and a plurality of light-emitting devices, such as the light-emitting device602. The plurality of light-emitting devices602is arranged in an array on the substrate8and electrically connected to a circuit on the substrate8. Each of the light-emitting devices602includes a first light-emitting unit which can emit a red light, the second light-emitting unit which can emit a blue light, and the third light-emitting unit which can emit a green light. Therefore each of the light-emitting devices602can be regarded as one pixel. The longitudinal direction of the first light-emitting unit1is perpendicular to the longitudinal direction of the second light-emitting unit2, and perpendicular to the longitudinal direction of the third light-emitting unit3. The longitudinal direction of the second light-emitting unit2is parallel to the longitudinal direction of the third light-emitting unit3. The arrangement direction of the longitudinal sides of each of the first light-emitting unit of the light-emitting devices602is horizontal direction (the first direction). The arrangement direction of each of the longitudinal sides of the second light-emitting unit of the light-emitting devices602is vertical direction (the second direction). The arrangement direction of each of the longitudinal sides of the third light-emitting unit of the light-emitting devices602is vertical direction (the second direction). The second direction is perpendicular to the first direction. The arrangement direction of the longitudinal sides of each of the second light-emitting units is same as that of each of the third light-emitting units. The surface of the substrate8has a light-absorbing layer (not shown) to improve the contrast of the display module1000when displaying images. The material of the light-absorbing layer can refer to the related descriptions ofFIG.9. In another embodiment, the light-emitting device can be the light-emitting device601.

FIG.5andFIG.6disclose a light-emitting device which includes a plurality of light-emitting units stacked in a single package. Some of the light-emitting units are arranged along a horizontal direction and some of the light-emitting units are arranged along a vertical direction.FIG.7explains in detail how to manufacture the light-emitting device ofFIG.6by a paste containing an insulating material and conductive particles. The above stacking method can also be applied to a light-emitting device with multiple light-emitting wavelength bands. Comparing to a light-emitting device with multiple light-emitting wavelength bands formed by epitaxial growth, the light-emitting device with multiple light-emitting wavelength bands formed in package structure is easier to manufacture and easier to control the light-emitting quality. As shown inFIG.13,FIG.13is a top view of the light-emitting device800. The light-emitting device800can emit a light with multiple light-emitting wavelength bands or with a wide light-emitting wavelength band. The light emitted from light-emitting device800depends on the selection and combination of the light-emitting wavelengths of the plurality of light-emitting units. The light-emitting device800includes a supporting body4, and a first light-emitting unit1, a second light-emitting unit2, a third light-emitting unit3, and a fourth light-emitting unit5which are arranged on the supporting body4. The second light-emitting unit2, the third light-emitting unit3, and the fourth light-emitting unit5are arranged along a horizontal direction on the first light-emitting unit1, and cover different portions of the light-emitting surface of the first light-emitting unit1. The light-emitting surfaces of the light-emitting units1,2,3, and5have the same normal direction. In a top view, the second light-emitting unit2, the third light-emitting unit3, and the fourth light-emitting unit5are physically separated from each other. The second light-emitting unit2is partially overlapped the first light-emitting unit1, the third light-emitting unit3is partially overlapped the first light-emitting unit1, the fourth light-emitting unit5is partially overlapped the first light-emitting unit1. The first light-emitting unit1has a plurality of light-emitting areas separated by the light-emitting units2,3,5and not be covered. In an embodiment, the light-emitting units2,3,5are separated from each other and located between the leftmost side and the rightmost side of the first light-emitting unit1. Hence, the first light-emitting unit1has four light-emitting areas which are separated from each other and not covered. In another embodiment, some of the light-emitting units2,3,5located at the leftmost or rightmost side of the first light-emitting unit1, therefore, the first light-emitting unit1has at least one uncovered light-emitting area. For example, the second light-emitting unit2is located at the leftmost side of the first light-emitting unit1, and the third light-emitting unit3is located at the rightmost side of the first light-emitting unit1. The fourth light-emitting unit5is physically separated from the second light-emitting unit2and the third light-emitting unit3, and is located between the leftmost side and the rightmost side of the first light-emitting unit1. Hence, and the first light-emitting unit1has two separated, uncovered light-emitting areas. In another embodiment, some of the light-emitting units2,3,5can be arranged side by side and arranged along a horizontal direction on the first light-emitting unit1, so that the first light-emitting unit1has at least one uncovered light-emitting area. For example, the light-emitting units2,3,5are located between the leftmost side and the rightmost side of the first light-emitting unit1, the second light-emitting unit2and the third light-emitting unit3are arranged side by side without gaps and arranged along a horizontal direction. The fourth light-emitting unit5is physically separated from the second light-emitting unit2and the third light-emitting unit3. Hence, the first light-emitting unit1has three separated, uncovered light-emitting areas.

In order to facilitate the stacking of the second light-emitting units2,3,5on the first light-emitting unit1, the first light-emitting unit1does not have a growth substrate or has a thinned growth substrate, so that the thickness of the first light-emitting unit1is thinner than those of the light-emitting units2,3,5. In another embodiment, in order to reduce the thickness of the light-emitting device, the light-emitting units1,2,3,5do not have the growth substrate or have a thinned growth substrate. The light-emitting units2,3,5and the light-emitting unit1are joined by a bonding material, and the bonding material can include glue. The glue can comprise polyimide, benzocyclobutene (BCB), perfluorocyclobutane (PFCB), epoxy, Su8, or spin-on glass (SOG). In another embodiment, there is no bonding material between the light-emitting units1,2, between the light-emitting units1,3, and between the light-emitting units1,5. After the light-emitting units1,2,3,5are disposed on the supporting body4, a glue material covers the light-emitting units1,2,3,5to protect the light-emitting units1,2,3,5. The material of the glue can refer to aforementioned description.

The light-emitting units1,2,3,5can be electrically connected to an external power source by flip bonding. LikeFIG.6, the second light-emitting unit2includes a portion overlapping the first light-emitting unit1, and another two portions without overlapping the first light-emitting unit1located on opposite sides of the portion overlapping the first light-emitting unit1. The third light-emitting unit3includes a portion overlapping the first light-emitting unit1, and another two portions without overlapping the first light-emitting unit1located on opposite sides of the portion overlapping the first light-emitting unit1. The fourth light-emitting unit5includes a portion overlapping the first light-emitting unit1, and another two portions without overlapping the first light-emitting unit1located on opposite sides of the portion overlapping the first light-emitting unit1. All of the electrode pads of the light-emitting units1,2,3,5are disposed on the bottom surface corresponding to the light-emitting surface, and are electrically connected to the supporting body4by flip bonding. The materials and bonding steps of the electrode pads and the supporting body4can refer to the related descriptions ofFIG.7andFIG.8.

The light-emitting device800can emit a light with a wavelength band from red light to infrared light. For example, the first light-emitting unit1can emit a red light having a wavelength of 630 to 780 nm, and the light-emitting units2,3, and5can emit an infrared light having a wavelength larger than 780 nm, for example, 810 nm, 850 nm, 880 nm, 910 nm, 940 nm, 970 nm, or 1050 nm. In another embodiment, some of the light-emitting units1,2,3,5can simultaneously emit two lights with two wavelengths, for example, the first light-emitting unit1can emit a light with a wavelength less than 720 nm, the second light-emitting unit2can emit an infrared light with two wavelengths of 810 nm and 850 nm, the third light-emitting unit3can emit an infrared light with two wavelengths of 880 nm and 910 nm, and the fourth light-emitting unit5can emit an infrared light with a wavelength larger than 1000 nm. The light emitted from the first light-emitting unit1can penetrate at least one of the second light-emitting unit2, the third light-emitting unit3, and the fourth light-emitting unit5, and the light emitted from the first light-emitting unit1cannot penetrate at least one of the second light-emitting unit2, the third light-emitting unit3, and the fourth light-emitting unit5. The shape of the light-emitting unit can be a rectangle, a circle, a triangle, a square, a parallelogram, a trapezoid, or other polygonal shapes. The shape of the light-emitting unit is an exemplary here and is not a limitation of the disclosure. In an embodiment, each of the light-emitting units has a rectangular shape. In another embodiment, the shape of each of the light-emitting units can be same, different, or some can be the same and some are different. The number of light-emitting units is four which is exemplary here and is not a limitation of the invention. In another embodiment, the number of light-emitting units is at least greater than two. The light-emitting wavelength of the light-emitting unit is an exemplary here and is not a limitation of the disclosure. In another embodiment, some or all of the light-emitting units emit the lights that are different from red or infrared light.

In order to facilitate the stacking of the second light-emitting unit2on the first light-emitting unit1, the first light-emitting unit1does not have a growth substrate or has a thinned growth substrate, so that the thickness of the first light-emitting unit1is thinner than those of the light-emitting unit2. In another embodiment, in order to reduce the thickness of the light-emitting device, the light-emitting units1,2do not have the growth substrate or have a thinned growth substrate. The light-emitting units2and the light-emitting unit1are joined by a bonding material, and the bonding material can include glue. The glue can comprise polyimide, benzocyclobutene (BCB), perfluorocyclobutane (PFCB), epoxy, Su8, or spin-on glass (SOG). In another embodiment, there is no bonding material between the light-emitting units1,2. After the light-emitting units1,2are disposed on the supporting body4, a glue material covers the light-emitting units1,2to protect the light-emitting units1,2. The material of the glue can refer to aforementioned description. The light emitted from the first light-emitting unit1penetrates the second light-emitting unit2. Therefore, the lights emitted from the first light-emitting unit1and the second light-emitting unit2are coaxial, and the light-emitting device900is a light-emitting device which can emit coaxial light.

It will be apparent to those having ordinary skill in the art that various modifications and variations can be made to the devices in accordance with the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure covers modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.