Light-emitting element and light-emitting device

Abstract

The utility model provides a light-emitting element and a light-emitting device. The light-emitting element comprises a substrate and an LED chip, and the orthographic projection of the LED chip on the first surface of the substrate and the first surface of the substrate are both square; an electrode is arranged at each of a pair of diagonal positions on the surface, deviating from the substrate, of the LED chip, and the electrodes are electrically connected with the substrate. The two electrodes, deviating from the surface of the substrate, of the LED chip are respectively arranged at one pair of diagonal positions, so that current is more uniformly injected into each region of the chip on the premise that the light-emitting area of the chip is not reduced; the luminous intensity on the surface of the chip is more uniformly distributed, and the illumination quality is improved; the light-emitting element can generate more uniform light spots; the lower voltage requirement can be met, the energy efficiency of the light-emitting element is improved, and the energy consumption is reduced; the temperature and brightness uniformity of the light-emitting element are improved, and the reliability and performance of the light-emitting element are enhanced.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor devices, and in particular to a light-emitting element and a light-emitting device. Background Art

[0002] Light Emitting Diode (LED) and its packaging components are widely used in lighting, display, automobile, communication and signal indication. The chip structure of LED is mainly divided into three categories: face-up structure, flip-chip structure and vertical structure. Among them, the vertical structure chip has attracted much attention due to its good high current resistance.

[0003] In the design of vertical structure chips, in order to withstand higher currents, multiple electrodes are usually required, and the package end is connected to the electrode by welding multiple gold wires. The electrode structure includes hole electrodes, long strip electrodes, etc., among which hole electrodes are the most common design.

[0004] For sizes within 1mm 2 ~4mm 2 LED chips are generally equipped with two holes with the same polarity, mostly positive electrodes. In order to facilitate wire bonding, the two electrodes are usually located on the same side of the chip. When the LED is working, the current is first injected from the electrode and then diffuses to the entire LED chip. Due to the influence of the chip structure and its own resistance, the current is more concentrated at the initial injection end (around the electrode), and the current is lower at a position far away from the electrode, which causes the temperature and brightness uniformity of the light-emitting device to deteriorate.

[0005] In order to solve the problem that when a vertically structured light-emitting element works under high current conditions, the uneven current distribution may easily cause local overheating of the chip and uneven brightness, thereby affecting the overall performance and service life of the light-emitting element, the present application provides a light-emitting element and a light-emitting device. Utility Model Content

[0006] In view of the defects and shortcomings of the vertical structure chip of the light-emitting element in the prior art under high current working conditions, due to the uneven current distribution, the chip is locally overheated and the brightness is uneven, which affects the overall performance and service life of the light-emitting element, the present application provides a light-emitting element and a light-emitting device. Without setting more electrodes, the light-emitting element sets two electrodes on the surface of the LED chip away from the substrate at a pair of diagonal positions, respectively, and achieves a more uniform current distribution without reducing the chip light-emitting area by optimizing the design and distribution of the electrodes, thereby improving the temperature and brightness uniformity of the light-emitting element and enhancing the reliability and performance of the light-emitting element.

[0007] An embodiment of the present application provides a light-emitting element, comprising at least:

[0008] A substrate, the substrate comprising a first surface and a second surface arranged opposite to each other, and the first surface is square;

[0009] An LED chip, wherein the LED chip is fixed to the first surface of the substrate, and the LED chip is a vertical structure chip, and its orthographic projection on the substrate is a square;

[0010] Wherein, a first electrode is disposed at each of a pair of diagonal positions on the surface of the LED chip facing away from the substrate, and the electrodes are electrically connected to the substrate.

[0011] Another embodiment of the present application provides a light emitting device, including:

[0012] A circuit board and a plurality of light-emitting units arranged on the circuit board, wherein the light-emitting units include the light-emitting elements mentioned above.

[0013] As described above, the light-emitting element and the light-emitting device of the present application have the following beneficial effects:

[0014] The light-emitting element of the present application, without setting more electrodes, realizes that the current is injected into various areas of the chip more evenly without reducing the light-emitting area of ​​the chip by setting two electrodes on the surface of the LED chip facing away from the substrate at a pair of diagonal positions respectively; due to the uniformity of current injection, the luminous intensity on the chip surface is also more evenly distributed, thereby improving the lighting quality; the improved light-emitting element can produce a more uniform light spot; and the light-emitting element can achieve a lower voltage requirement, thereby improving the energy efficiency of the light-emitting element and reducing energy consumption; due to the reduction in operating voltage and the uniformity of current distribution, the heat loss of the chip is reduced, which helps to improve the energy efficiency of the light-emitting element and extend its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram showing the structure of a light-emitting element in the prior art.

[0016] Figure 2 Shown is a schematic diagram of the structure of the light-emitting element provided in Example 1 of the present application.

[0017] Figure 3 Shown is a schematic diagram of the structure of the LED chip in the light-emitting element provided in Example 1 of the present application.

[0018] Figure 4 Shown is a schematic structural diagram of a light-emitting device provided in Embodiment 2 of the present application.

[0019] Component number description

[0020] 10, circuit board; 20, light-emitting unit; 100, substrate; 110, first diagonal line; 120, second diagonal line; 200, LED chip; 210, electrode; 220, welding wire; 230, metal layer; 240, insulating layer; 250, reflective layer; 260, semiconductor stack; 261, first semiconductor layer; 262, active layer; 263, second semiconductor layer; 270, conductive hole. DETAILED DESCRIPTION

[0021] The following is an explanation of the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0022] The present application provides a light-emitting element, comprising at least:

[0023] A substrate, the substrate comprising a first surface and a second surface arranged opposite to each other, and the first surface is square;

[0024] An LED chip, wherein the LED chip is fixed to the first surface of the substrate, and the LED chip is a vertical structure chip, and its orthographic projection on the substrate is a square;

[0025] Wherein, on the surface of the LED chip facing away from the substrate, an electrode is disposed at each of a pair of diagonal positions, and the electrode is electrically connected to the substrate.

[0026] The light-emitting element provided in this embodiment sets the two electrodes on the surface of the LED chip facing away from the substrate at a pair of diagonal positions without increasing the number of electrodes, so that the current is more evenly injected into various areas of the chip without reducing the light-emitting area of ​​the chip; due to the uniformity of current injection, the luminous intensity on the chip surface is also more evenly distributed, which is beneficial to improving the lighting quality; the improved light-emitting element can produce a more uniform light spot, which is crucial to improving the visual effect and lighting consistency of the lighting equipment; due to the uniformity of current expansion, the light-emitting element can achieve lower voltage requirements when working, which is beneficial to improving the energy efficiency of the light-emitting element and reducing the energy consumption of the light-emitting element; due to the reduction of the operating voltage of the light-emitting element and the uniformity of current distribution, the heat loss of the light-emitting element is reduced, which is beneficial to improving the energy efficiency of the light-emitting element and extending the service life of the light-emitting element.

[0027] In some embodiments, the first surface of the substrate includes a first diagonal line and a second diagonal line, the first diagonal line passes through one pair of opposite corners of the first surface, the second diagonal line passes through another pair of opposite corners of the first surface, and the intersection point of the first diagonal line and the second diagonal line is the center point of the first surface;

[0028] The center point of the orthographic projection of the LED chip on the substrate coincides with the center point of the first surface, and one pair of two opposite sides is perpendicular to the first diagonal line, and the other pair of two opposite sides is perpendicular to the second diagonal line.

[0029] In this embodiment, the center point of the orthographic projection of the LED chip on the substrate is coincident with the center point of the first surface, so that the light-emitting surface of the LED chip is located at the center of the light-emitting element; the orthographic projection of the LED chip on the substrate is arranged so that two opposite sides thereof are perpendicular to the first diagonal line of the first surface, and the other two opposite sides thereof are perpendicular to the second diagonal line of the first surface, so that when the electrode is connected to the substrate, it is convenient to set the substrate and facilitate wiring.

[0030] In some embodiments, the ratio of the side length of the orthographic projection of the LED chip on the substrate to the side length of the first surface is between 0.3 and 0.6.

[0031] In this embodiment, the light-emitting effect of the light-emitting surface of the light-emitting element is improved by limiting the ratio of the side length of the orthographic projection of the LED chip on the substrate to the side length of the first surface.

[0032] In some embodiments, the electrodes are electrodes of the same polarity.

[0033] In some embodiments, the electrode is electrically connected to the substrate via a welding wire.

[0034] In some embodiments, the LED chip is connected to the substrate via a bonding adhesive layer.

[0035] In some embodiments, a packaging layer is further included, and the packaging layer is disposed on the surface of the LED chip facing away from the substrate, the side of the LED chip, and the surface of the first surface not covered by the LED chip.

[0036] In some embodiments, along the direction from the second surface to the first surface, the LED chip includes a metal layer, an insulating layer, and a reflective layer stacked in sequence from the first surface;

[0037] A semiconductor stack is disposed on a partial area of ​​a surface of the reflective layer on a side away from the insulating layer, wherein the semiconductor stack comprises a second semiconductor layer, an active layer and a first semiconductor layer stacked in sequence from the reflective layer;

[0038] The electrodes are arranged at a pair of diagonal positions in an area of ​​the reflective layer that is away from the insulating layer and is not covered by the semiconductor stack.

[0039] In some embodiments, a conductive hole is provided in the semiconductor stack, and the conductive hole penetrates the second semiconductor layer, the active layer and a portion of the first semiconductor layer;

[0040] The insulating layer and the metal layer are sequentially arranged on the sidewalls of the conductive hole from the outside to the inside, and the metal layer passes through the conductive hole and is electrically connected to the first semiconductor layer.

[0041] Another embodiment of the present application provides a light-emitting device, including a circuit board and a plurality of light-emitting units arranged on the circuit board, wherein the light-emitting units include the light-emitting elements provided in the present application.

[0042] The light-emitting unit in the light-emitting device of the present embodiment adopts the light-emitting element provided by the present application. Since the light-emitting element provided by the present application arranges the two electrodes on the surface of the LED chip facing away from the substrate at a pair of diagonal positions without increasing the number of electrodes, the current is more evenly injected into various areas of the chip without reducing the light-emitting area of ​​the chip. This is beneficial to improving the lighting quality of the light-emitting device of the present application, the visual effect and lighting consistency of the light-emitting device, improving the energy efficiency of the light-emitting device, reducing the energy consumption of the light-emitting device, and extending the service life of the light-emitting device.

[0043] like Figure 1 As shown, a light-emitting element in the prior art is shown, which includes a substrate 100 and an LED chip 200. The substrate 100 includes an upper surface and a lower surface arranged oppositely, and the LED chip 200 includes a light-emitting surface and a backlight surface arranged oppositely, and a side surface arranged between the light-emitting surface and the backlight surface. The backlight surface of the LED chip 200 is fixedly connected to the upper surface of the substrate 100. Among them, the orthographic projection of the LED chip 200 on the upper surface of the substrate 100 has each side parallel to the corresponding side of the first surface of the substrate 100; two electrodes 210 arranged on the light-emitting surface of the LED chip 200 are electrically connected to the substrate 100 through welding wires 220. For the convenience of welding wires, the two electrodes 210 are located on the same side of the LED chip 200. When the light-emitting element is working, current is first injected from the electrode 210 and diffuses to the entire LED chip 200. Due to the structure of the LED chip 200 and the influence of its own resistance, the current is generally concentrated at the initial injection end (around the electrode 210), and the current is lower at locations far away from the electrode 210, resulting in poor temperature uniformity and brightness uniformity of the light-emitting element.

[0044] In view of the above defects, the present application provides a light emitting element and a light emitting device, which are now described in detail through the following embodiments.

[0045] Embodiment 1

[0046] This embodiment provides a light emitting element, such as Figure 2 As shown, the light-emitting element includes a substrate 100 and an LED chip 200. The substrate 100 includes a first surface (which may be the upper surface of the substrate 100) and a second surface (which may be the lower surface of the substrate 100) which are arranged opposite to each other, and the shape of the first surface is a square; the LED chip 200 includes a light-emitting surface, a backlight surface, and a side surface arranged between the light-emitting surface and the backlight surface, the backlight surface of the LED chip 200 is fixedly connected to the first surface of the substrate 100, the shape of the orthographic projection of the LED chip 200 on the first surface of the substrate 100 is a square, and the LED chip 200 is a vertical structure chip. The surface of the LED chip 200 facing away from the substrate 100 (the light-emitting surface of the LED chip 200) includes four corners, and two opposite corners are defined as a pair of diagonal corners, which are divided into two pairs of diagonal corners, and each pair of diagonal corners is provided with an electrode 210, and the electrode 210 is electrically connected to the substrate 100. The light-emitting element of this embodiment maintains the same number of two electrodes 210 on its light-emitting surface, and respectively arranges the two electrodes 210 on the light-emitting surface of the LED chip 200 at a pair of diagonal positions on the light-emitting surface, so as to achieve more uniform injection of current into various areas of the chip without reducing the light-emitting area of ​​the LED chip 200; due to the improvement of the uniformity of current injection, the luminous intensity of the light-emitting surface of the LED chip is also more evenly distributed, which is beneficial to improving the lighting quality of the light-emitting element; the improved light-emitting element can produce a more uniform light spot, which is crucial to improving the visual effect and lighting consistency of the light-emitting element; due to the uniformity of current expansion, the light-emitting element can achieve lower voltage requirements when working, which is beneficial to improving the energy efficiency of the light-emitting element and reducing the energy consumption of the light-emitting element; due to the reduction of the working voltage of the light-emitting element and the uniformity of current distribution, the heat loss of the light-emitting element is reduced, which is beneficial to extending the service life of the light-emitting element.

[0047] In an optional embodiment, if Figure 2As shown, the shape of the first surface of the substrate 100 is a square, and the first surface includes a first diagonal line 110 passing through one pair of diagonals, and a second diagonal line 120 passing through another pair of diagonals, and the intersection of the first diagonal line 110 and the second diagonal line 120 is the center point of the first surface. The orthographic projection of the LED chip 200 on the first surface of the substrate 100 is a square, and its center point coincides with the center point of the first surface, so that the light-emitting surface of the LED chip 200 is located at the center of the light-emitting element; and the orthographic projection of the LED chip 200 on the first surface of the substrate 100, wherein a pair of two parallel sides are perpendicular to the first diagonal line 110 of the first surface, and another pair of two parallel sides are perpendicular to the second diagonal line 120 of the first surface, so that when the electrode 210 is connected to the substrate 100, it is convenient to set the substrate 100 and facilitate wire bonding.

[0048] The substrate 100 is a conductive substrate, and the material of the conductive substrate may be, for example, silicon, metal, or a composite structure material, etc. The metal material may be, for example, copper and aluminum, etc.

[0049] In an optional embodiment, the ratio of the side length of the orthographic projection of the LED chip 200 on the first surface of the substrate 100 to the side length of the first surface is between 0.3 and 0.6. Specifically, the ratio of the side length of the orthographic projection of the LED chip 200 on the first surface of the substrate 100 to the side length of the first surface can be, for example, 0.3, 0.4, 0.5, 0.6, etc. Under this condition, it is beneficial to improve the luminous effect and luminous intensity of the light-emitting element.

[0050] In an optional embodiment, the two electrodes 210 located on the light emitting surface of the LED chip 200 are electrodes of the same polarity, for example, they may be P-type electrodes, and the material of the P-type electrodes may be, for example, Ti, Pt, Ni, Au, etc.

[0051] In an optional embodiment, the electrode 210 is electrically connected to the substrate 100 via a bonding wire 220. The bonding wire 220 may be made of, for example, gold, aluminum, copper, silver, or an alloy. The alloy may be, for example, a gold-copper alloy or a gold-palladium alloy.

[0052] In an optional embodiment, the backlight surface of the LED chip 200 is connected to the first surface of the substrate 100 via a bonding adhesive layer (not shown in the figure). The material of the bonding adhesive layer can be, for example, conductive adhesive.

[0053] In an optional embodiment, the light-emitting element also includes a packaging layer (not shown in the figure), which completely covers the LED chip 200 (the light-emitting surface and side surfaces of the LED chip), the surface of the first surface not covered by the LED chip 200, and the welding wire 220. The packaging layer encapsulates the LED chip 200, the surface of the first surface not covered by the LED chip 200, and the welding wire 220 to achieve the sealing of the light-emitting element, isolate the air, prevent moisture, etc., and extend the service life of the light-emitting element.

[0054] In an optional embodiment, the LED chip 200 in the light emitting element is a vertical structure chip, such as Figure 3 As shown, along the direction from the second surface to the first surface (from bottom to top), the LED chip 200 includes a metal layer 230, an insulating layer 240 and a reflective layer 250 stacked in sequence from the first surface, and a semiconductor stack 260 is arranged in a partial area of ​​the surface of the side of the reflective layer 250 away from the insulating layer 240, and the semiconductor stack 260 includes a second semiconductor layer 263, an active layer 262 and a first semiconductor layer 261 stacked in sequence from the surface of the reflective layer 250 away from the insulating layer 240; an area of ​​the surface of the reflective layer 250 away from the insulating layer 240 that is not covered by the semiconductor stack 260, wherein a pair of diagonal positions are respectively provided with electrodes 210; a conductive hole 270 is arranged in the semiconductor stack 260, and the conductive hole 270 passes through the second semiconductor layer 263, the active layer 262 and a part of the first semiconductor layer 261. Figure 3 Only one insulating layer 240 is illustrated in the example, and there may be at least two insulating layers 240 in actual production. The metal layer 230 is filled in the remaining space after the insulating layer 240 is set in the conductive hole 270 (that is, the metal layer 230 is set on the side of the conductive hole 270 close to the first semiconductor layer 261 and on the side wall after the insulating layer 240 is filled), and the metal layer 230 is electrically connected to the first semiconductor layer 261 through the conductive hole 270.

[0055] The first semiconductor layer 261 is an N-type semiconductor layer that provides electrons through N-type doping. The N-type semiconductor layer can be formed by doping Si, Ge, Sn, Se, Te, etc. in the semiconductor. The second semiconductor layer 263 is a P-type semiconductor layer that provides holes through P-type doping. The P-type semiconductor layer can be formed by doping Mg, Zn, Ca, Sr, Ba, etc. in the semiconductor. The active layer 262 can be a single quantum well structure or a multiple quantum well (MQWs) structure. The multiple quantum well structure is formed by alternately stacking quantum well layers and quantum barrier layers. The quantum barrier layers can be GaN layers, AlGaN layers, or AlGaInP layers. Optionally, the active layer 262 may include multiple quantum well structures such as GaN / AlGaN, InAlGaN / InAlGaN, InGaN / AlGaN, GaInP / AlGaInP, GaInP / AlInP, or InGaAs / AlInGaAs. In order to improve the light emitting efficiency of the active layer 262 , it can be achieved by changing the depth of the quantum well, the number of layers, thickness and / or other characteristics of the paired quantum wells and quantum well barriers in the active layer 262 .

[0056] The reflective layer 250 may be formed of at least one metal selected from Ag, Al, Ni, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf. The reflective layer 250 can reflect the light radiated from the semiconductor stack 260 toward the side of the substrate 100 back to the semiconductor stack 260 and radiate out from the light emitting side of the semiconductor stack 260.

[0057] The material of the insulating layer 240 is an insulating material, for example, SiO 2 、SiN、SiO x N y 、TiO 2 、Si 3 N 4 、Al 2 O 3 、TiN、AlN、ZrO 2 、TiAlN、TiSiN、HfO 2 、TaO 2 MgF 2 The metal layer 230 has at least two metal layers, one of which is an N-electrode layer, and the material of the N-electrode layer can be, for example, Al, Ag, Cr, Pt, TiW; the other metal layer is a bonding layer, and one side of the metal layer 230 is adhered to the substrate 100. The bonding layer is usually made of metals such as gold, tin, titanium, nickel, platinum, etc., and the bonding layer can be a combination of multiple materials.

[0058] Embodiment 2

[0059] This embodiment provides a light emitting device, such as Figure 4 As shown, it includes a circuit board 10 and a plurality of light-emitting units 20 arranged on the circuit board 10, and the light-emitting units 20 include the light-emitting element provided in Example 1. In the light-emitting element of Example 1, without increasing the number of electrodes, two electrodes 210 on the surface of the LED chip 200 away from the substrate 100 are respectively arranged at one pair of diagonal positions of the light-emitting surface of the LED chip 200, so that the current is more evenly injected into various areas of the chip without reducing the light-emitting area of ​​the chip, which is conducive to improving the lighting quality of the light-emitting element, improving the visual effect and lighting consistency of the light-emitting element, improving the energy efficiency of the light-emitting element, reducing the energy consumption of the light-emitting element, and extending the service life of the light-emitting element.

[0060] The above-mentioned light-emitting device can be used for flashlights of handheld communication equipment, lighting, vehicle lighting, stage lights, etc., and can effectively improve the current uniformity of the light-emitting device, improve the lighting quality of the light-emitting device, improve the energy efficiency of the light-emitting device, reduce the energy consumption of the light-emitting device, and extend the service life of the light-emitting device.

[0061] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A light emitting element, characterized in that: At least: A substrate, the substrate comprising a first surface and a second surface arranged opposite to each other, and the first surface is square; An LED chip, wherein the LED chip is fixed to the first surface of the substrate, and the LED chip is a vertical structure chip, and its orthographic projection on the substrate is a square; Wherein, on the surface of the LED chip facing away from the substrate, an electrode is disposed at each of a pair of diagonal positions, and the electrode is electrically connected to the substrate.

2. The light emitting element according to claim 1, characterized in that The first surface of the substrate comprises a first diagonal line and a second diagonal line, the first diagonal line passes through one pair of opposite corners of the first surface, the second diagonal line passes through another pair of opposite corners of the first surface, and the intersection point of the first diagonal line and the second diagonal line is the center point of the first surface; The center point of the orthographic projection of the LED chip on the substrate coincides with the center point of the first surface, and One pair of opposite sides is perpendicular to the first diagonal line, and the other pair of opposite sides is perpendicular to the second diagonal line. straight.

3. The light emitting element according to claim 1 or 2, characterized in that: The ratio of the side length of the orthographic projection of the LED chip on the substrate to the side length of the first surface is between 0.3 and 0.

6.

4. The light emitting element according to claim 1, characterized in that The electrodes are electrodes of the same polarity.

5. The light emitting element according to claim 1, wherein: The electrode is electrically connected to the substrate via a welding wire.

6. The light emitting element according to claim 1, wherein: The LED chip and the substrate are connected via a solid crystal adhesive layer.

7. The light emitting element according to claim 1, characterized in that It also includes a packaging layer, wherein the packaging layer is arranged on the The surface of the LED chip facing away from the substrate, the side of the LED chip, and the first surface not covered by the substrate The surface covered by LED chips.

8. The light emitting element according to claim 1, characterized in that Along the direction from the second surface to the first surface, the LED chip includes a metal layer, an insulating layer and a reflective layer stacked in sequence from the first surface; A semiconductor stack is disposed on a partial area of ​​a surface of the reflective layer on a side away from the insulating layer, wherein the semiconductor stack comprises a second semiconductor layer, an active layer and a first semiconductor layer stacked in sequence from the reflective layer; The electrodes are arranged at a pair of diagonal positions in an area of ​​the reflective layer that is away from the insulating layer and is not covered by the semiconductor stack.

9. The light emitting element according to claim 8, characterized in that A conductive hole is provided in the semiconductor stack, and the conductive hole penetrates the second semiconductor layer, the active layer and a part of the first semiconductor layer; The insulating layer and the metal layer are sequentially arranged on the sidewalls of the conductive hole from the outside to the inside, and the metal layer passes through the conductive hole and is electrically connected to the first semiconductor layer.

10. A light emitting device, characterized in that: The invention comprises a circuit board and a plurality of light-emitting units arranged on the circuit board, wherein the light-emitting units comprise the light-emitting elements according to any one of claims 1 to 9.

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