LED chip and aviation obstruction beacon using same

Abstract

The invention relates to an LED chip and an aviation obstruction beacon using the same. The upper surface of the substrate of the LED chip is an inclined upper surface, and the inclination angle of the upper surface of the substrate is theta 1; a plurality of inclined grooves are formed in the inclined upper surface of the base plate, and the included angle between the right bottom surface of each inclined groove and the upper surface of the base plate is theta 2; and a refraction layer with a high refractive index is arranged on the semiconductor layer in the inclined groove, and the refraction layer enables the light vertically emitted by the LED semiconductor layer on the right bottom to pass through the refraction layer and then deflect to the left for theta multi-fold due to light refraction. The LED chip is multi-folded through theta1 + theta2 + theta, even if the LED chip is horizontally mounted, light emitted by a semiconductor layer of the LED chip can be bent by a large angle in the horizontal direction, a lens and an external reflector do not need to be packaged, and meanwhile, by optimizing an electrode structure and the like, the chip cannot be difficult to dissipate heat or crack due to the fact that the right side of a substrate is thick.

Description

Technical Field:

[0001] The present invention relates to the field of LEDs, and particularly to an LED chip. Background Art:

[0002] An LED chip generally includes a substrate and p-layer, light-emitting layer, and n-layer thin films sequentially grown on the substrate. When the substrate is placed horizontally, the light-emitting area in the up-and-down direction is the largest. Therefore, the general light-emitting angle is top emission or bottom emission.

[0003] There is a need to make the horizontally mounted LED chip emit light in the horizontal direction. If it is necessary to adjust the light-emitting angle of the horizontally placed LED chip to lateral emission, the encapsulant for encapsulating the lamp beads can be made into a lens shape, and the lens of the lens encapsulant is used to adjust the light-emitting angle value to horizontal. An external reflector can also be assisted in setting, and a metal reflector is set outside the LED lamp beads to further adjust the light-emitting direction to horizontal.

[0004] Making the encapsulant into a lens shape requires a thick encapsulant body, which is not conducive to the heat dissipation of the LED, especially for high-power LEDs. The heat dissipation performance directly affects its service life. In addition, when assembling multiple LED lamp beads into a lighting fixture, adding a metal reflector outside the LED lamp beads can adjust the light-emitting direction to horizontal. However, on the one hand, it will increase the complexity of the lighting fixture, increase the material cost and installation labor cost of the lighting fixture. On the other hand, the metal reflector will also occupy a large amount of installation space. Summary of the Invention:

[0005] The present invention provides an LED chip that can adjust the light-emitting angle of the LED chip, so that the direction with the strongest light-emitting intensity (defined as the light-emitting elevation angle, that is, the angle between the angle with the strongest light emission and the horizontal plane) is approximately in the horizontal direction, for example, within -5 to 30 degrees in the horizontal direction, for example, within 0 to 12 degrees, for example, 0 degrees, 2.5°.

[0006] <Semiconductor layer of the LED chip>

[0007] The LED chip includes a substrate, a semiconductor layer located on the substrate. The semiconductor layer includes an n-type layer, a light-emitting layer, and a p-type layer sequentially arranged from bottom to top; further, the semiconductor layer includes a buffer layer, an n-type layer, a light-emitting layer, a p-type layer, and a current spreading layer sequentially arranged from bottom to top.

[0008] The LED chip may further include an upper electrode layer disposed above the semiconductor layer, such as a metal grid line electrode, which is in contact with the P-type layer or the current spreading layer of the semiconductor layer.

[0009] <Inclined upper surface of the LED substrate>

[0010] Among them, the upper surface of the substrate is not horizontally arranged, but is an inclined upper surface. The included angle between the inclined upper surface of the substrate and the horizontal plane, that is, the upper surface inclination angle of the substrate is θ1. The emitted light of the LED is bent towards the horizontal direction by using the inclined upper surface of the substrate.

[0011] The value range of the upper surface inclination angle θ1 of the substrate is preferably 0 < θ1 < 30°, more preferably 5 - 25°, and most preferably 10 - 20°, such as 20°. If the angle θ1 is too small, it is difficult to effectively bend the emitted light of the LED towards the horizontal direction. If the angle is too large, the thickness of one side ( Figure 1 the right side in the figure) of the substrate will be relatively thick, which is not conducive to obtaining the substrate and is not conducive to heat dissipation of the substrate. For example, when the length and width of the substrate are 1 mm and the upper surface inclination angle θ1 is 20°, if the thickness of the thin side ( Figure 1 the left side in the figure) of the substrate is about 80 μm, then the thickness of the thick side is 440 μm. The thickness of the thick side is exactly the initial thickness of a conventional sapphire substrate, and the thickness of the left side is exactly the thickness after thinning of a conventional LED substrate. If the substrate is greater than 20°, then it is necessary to further thin the thickness of the thin side of the substrate or increase the thickness of the thick side of the substrate.

[0012] <The inclined grooves on the inclined upper surface of the LED substrate>

[0013] A plurality of inclined grooves are provided in the inclined upper surface of the substrate. The inclined grooves are repeatedly arranged on the inclined upper surface. In the left - right direction, the length of the inclined upper surface between two adjacent inclined grooves is less than 1 / 5 of the length of the top surface of the inclined groove (that is, the missing upper surface of the inclined groove, which was originally the inclined upper surface of the substrate and disappeared when the inclined groove was etched on the substrate), so as to avoid the inclined upper surface between two adjacent inclined grooves occupying too large an area, because the right side wall of the inclined groove is the main left - emitting area. The number of inclined grooves is, for example, 3 - 100.

[0014] The inclined groove has a right bottom surface and a left bottom surface, and the two are perpendicular to each other at the intersection (that is, Figure 1 θ3 is 90° in the figure). The inclined groove is of a triangular prism type or a quasi - triangular prism type. The included angle between the right bottom surface of the inclined groove and the inclined upper surface of the substrate is θ2. The emitted light of the LED is bent towards the horizontal direction by using the right bottom surface of the inclined groove. The angle of θ2 is, for example, 10 - 60°, such as 10 - 40°, such as 40 degrees, 30 degrees, 20°. If the angle is too large, the right inclined surface is relatively steep, and it is difficult to deposit the semiconductor layer on this surface. A triangular prism means that the left bottom surface is a flat left bottom, and a quasi - triangular prism means that the left bottom wall of the inclined groove is further divided into left bottom a and left bottom b.

[0015] Preferably, the inclined grooves are parallel and spaced in the left - right direction and are not connected together. If they are connected together, the connection part is a sharp angle, the film layer stress is large, and the film - forming adhesion is poor.

[0016] Preferably, in the left - right direction, the length of the right bottom of the inclined groove is greater than that of the left bottom. For example, the length of the right bottom is more than 1.1 times that of the left bottom, such as more than 1.19 times, or more than 2 times. The right bottom is the main bottom surface that bends light to the left. By setting the right bottom larger, the intensity of the light emitted to the left can be ensured to be higher.

[0017] <Refractive layer in the inclined groove>

[0018] On the semiconductor layer in the inclined groove, a refractive layer with a high refractive index is provided to bend the emitted light of the LED in the horizontal direction. The refractive layer gradually thickens from the starting point at the upper right of the substrate inclined groove to the lower left, thus forming a triangular prism shape. The right - hand angle of the triangular prism, that is, the angle between the surface of the triangular prism in contact with the LED layer and the top surface of the triangular prism, is θ4. The angle θ4 of the refractive layer should not be too large, otherwise when light exits from the refractive layer with a high refractive index, total internal reflection is likely to occur and it is difficult to exit. The angle of θ4 is, for example, 5 < θ4 < 60°, such as 30°.

[0019] The refractive layer with a high refractive index has a refractive index greater than 1.4, such as 1.4 - 2.62. For example, the refractive layer material is TiO2, with a refractive index of 2.2 - 2.62; for example, the refractive layer material is Ta2O5, with a refractive index of 2.4; for example, the refractive layer is a SiO2 - TiO2 mixed layer, in which SiO2 and TiO2 are uniformly mixed, and the refractive index increases as the proportion of TiO2 with a large refractive index increases, and the refractive index varies between 1.4 and 2.2. The refractive layer is preferably prepared by the spin - coating method, which has a simple manufacturing process, low cost, and can form a relatively thick film layer. The refractive layer is also, for example, SiN x , with a refractive index between 1.8 and 2.4. The refractive index of stoichiometric Si3N4 is about 2.0, and the refractive index increases as the ratio of Si and N increases. SiNx is difficult to prepare by the spin - coating method and is not preferred. The present invention does not use SiNx.

[0020] <Light delivery layer in the inclined groove>

[0021] Using TiO2 with a high refractive index, the angle θ4 of the refractive layer cannot be too large, otherwise total internal reflection will occur. Therefore, the left bottom b must be set. However, the setting of the left bottom b will waste the area for setting the LED semiconductor layer. To reduce the waste of the semiconductor layer area, a light delivery layer is further provided on the refractive layer. The refractive index of the light delivery layer is less than that of the refractive layer. For example, the light delivery layer uses SiO2, with a refractive index of 1.45.

[0022] <Upper electrode of the LED chip>

[0023] On the inclined upper surface of the substrate, on the left bottom and right bottom of the inclined groove, an LED semiconductor layer is deposited, and an upper electrode is further deposited, which is a gate - line electrode. The upper electrode covers the upper surface of the semiconductor layer and is used to disperse and transmit current to the semiconductor layer.

[0024] The shape of the upper electrode is specially set to solve the problem that the right side of the substrate of the present invention is thicker and it is difficult to dissipate heat on the right side. Specifically, the left and right sides of the substrate can be divided into a conventional heat dissipation area and a strengthened heat dissipation area. The strengthened heat dissipation area is located on the right side of the substrate. The length starts from the right edge of the substrate and accounts for more than 1 / 2 of the total length in the left-right direction, for example, 1 / 2 to 2 / 3. The electrode grid lines on the left bottom wall of the inclined groove of the substrate are thick grid lines, whether in the conventional heat dissipation area or in the strengthened heat dissipation area; the electrodes on the inclined upper surface and the electrodes on the right bottom wall of the inclined groove are thick grid lines when in the strengthened heat dissipation area and are thin grid lines when in the conventional heat dissipation area. The LED semiconductor layers attached to the inclined upper surface and the right bottom wall of the inclined groove are the main light-emitting areas that emit light to the left. If the grid lines are set thick, although the heat dissipation is good, the light shielding is serious. Therefore, only in the strengthened heat dissipation area are the thicker grid lines set; for the semiconductor layer on the left bottom wall of the inclined groove, it is difficult for the light to emit to the left, so thick grid lines are set to improve the heat dissipation performance. The width of the thick grid lines is greater than the width of the thin grid lines; preferably, the width of the thick grid lines is 50 to 150 microns, and the width of the thin grid lines is 10 to 80 microns, for example, 10 to 50 microns.

[0025] <Light emission control of LED chip>

[0026] The light emitted from the left bottom wall of the inclined groove of the substrate is emitted to the right and is difficult to exit due to the shielding of the right bottom wall. Therefore, preferably, the left bottom wall is set as a non-light-emitting area. For example, at the upper end and the lower end of the left bottom wall, cutting grooves are provided, such as laser scribing cutting. In the direction from top to bottom of the semiconductor layer, the cutting grooves cut at least the current spreading layer, the P-type layer, and the light-emitting layer and stop on or within the N-type layer. And on the left bottom wall, on the LED semiconductor layers within the two cutting grooves at the upper end and the lower end, a dielectric layer is provided between the semiconductor layer and the upper electrode layer to block the power supply current from reaching this area, so that the power supply current is only supplied to the right bottom wall and the inclined upper surface, which helps to improve the light emission intensity of the right bottom wall and the inclined upper surface.

[0027] Among the multiple repeated inclined grooves, the structures between the inclined grooves are all the same. In this application, without special explanation, this is the case.

[0028] Alternatively, the oblique groove can be of different structures, for example, the angles between the right side wall of the oblique groove and the inclined upper surface are different, so as to obtain more diverse and more precisely controlled outgoing light elevation angles through different θ2 angles. Generally speaking, in addition to the angle precisely adjusted in the present application, LED light also has residual light emitted in other directions, and the light is mainly at the precisely adjusted angle, but has a certain diffusion angle. In order to more accurately control the diffusion angle, the angle between the right side wall of the oblique groove and the inclined upper surface can be adjusted to make different grooves correspond to different outgoing light elevation angles, for example, the outgoing light elevation angle is divided into twelve equal parts, each corresponding to the elevation angles of 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°. For another example, the elevation angle of the outgoing light is divided into 22 parts, 2.5° accounts for ten parts, and the other twelve parts correspond to 0°, 1°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, and 15° respectively. In this way, the 2.5° direction is the main luminous angle because the luminous area is the largest (the luminous angle of ten grooves is 2.5°, and there is only one groove at other angles), and there is also precise luminous distribution at the remaining angles, that is, the luminescence of the remaining angles except 2.5° is accurately enhanced.

[0029] Alternatively, the oblique grooves have the same structure, but the refractive index of the refractive layer in different oblique grooves is changed, that is, by adjusting θ 多折 , to obtain more diverse outgoing light elevation angles, for example, in the direction from right to left, the refractive index increases successively (for example, increases uniformly), so that θ 多折 Gradually increase the angle of the light emitted from the right bottom of the leftmost inclined groove of the LED chip to a final elevation angle of 0° (or -1°), while the final elevation angle of the light emitted from the right bottom of the rightmost inclined groove of the LED chip to a final elevation angle of 11° (or 6°). Thus, the chip's light-emitting elevation angle can be more accurately controlled within a certain angle range.

[0030] Alternatively, the oblique groove structure (e.g., the angle between the right side wall of the oblique groove and the inclined upper surface) and the refractive index of the refractive layer in the oblique groove are adjusted at the same time, so that the oblique groove structure of the inclined upper surface and the refractive index of the refractive layer in the oblique groove are different from left to right, so that the chip light elevation angle is precisely controlled within a certain angle range. For example, the light elevation angle is precisely controlled between 2 and 10 degrees for B-type low-intensity obstacle lights, for example, it is precisely controlled between 2 and 20 degrees for C-type low-intensity obstacle lights, for example, it is precisely controlled between -1 and 6 degrees or -1 and 2 degrees for medium-intensity and high-intensity obstacle lights.

[0031] The upper surface of the chip can be further covered with a passivation protection layer. For example, the semiconductor layer on the left bottom wall, and the semiconductor layer or the upper electrode layer on the inclined upper surface of the substrate are not covered with a refractive layer, etc., and are directly exposed to the air. A passivation protection layer such as SiN4, SiO2, etc. can be further provided in this area. The semiconductor layer on the right bottom wall does not need to be provided with a passivation protection layer because there are a refractive layer, a light delivery layer, etc. above it. Setting a passivation protection layer will affect the refraction direction.

[0032] <Positive and negative electrodes of the LED chip>

[0033] The LED chip is connected to an external circuit through electrodes. Preferably, the electrodes are respectively arranged on the lower surfaces of the left end and the right end of the LED chip, which is convenient for mounting on the circuit board. The positive and negative electrodes are the total electrodes of the LED chip, different from the upper electrode of the LED chip. The positive electrode introduces current from a power source (such as the power line on the circuit board) into the LED chip, transmits it to the upper electrode, is dispersed to the semiconductor layer by the upper electrode, and then is aggregated to the negative electrode (for example, aggregated to the negative electrode via the n-type layer) and then enters the power source again.

[0034] Preferably, a perforation is provided at the left end of the substrate, penetrating from the lower surface of the substrate to the n-type layer of the semiconductor layer of the LED chip. The perforation is filled with a metal electrode material, which serves as the negative electrode of the LED. The negative electrode includes a perforation electrode in the perforation and a pad at the bottom of the perforation; the perforation electrode is a mature electrode setting method for the LED chip, and in this application, the thickness of the left end of the substrate is the same as the thickness of the conventional thinned LED substrate (about 100 microns), and it is easy to realize the perforation.

[0035] Preferably, the above-mentioned perforation electrode does not completely fill the perforation, but covers the left and right side walls of the perforation, not exceeding 2 / 3 of the perimeter of the left side wall and 2 / 3 of the perimeter of the right side wall. The thermal expansion coefficient of the metal electrode is different from that of the LED substrate. The LED lamp has a stroboscopic requirement, for example, 20 - 60 times per minute, for example, more than 60 times per minute of flashing, for example, 80 times per minute. Alternating heat and cold easily cause cracks in the LED. For the substrate with a triangular cross-section in this application, the tip at the left end is a position prone to fracture, and the fracture surface is along the front-back direction (perpendicular to the left-right direction, into the paper surface). Setting the perforation electrode on the left and right side walls, the thermal expansion direction is along the paper surface direction rather than the left-right direction, and there will be no expansion force in the left-right direction on the tip at the left end, and it will not promote the fracture of the left end.

[0036] Preferably, the positive electrode at the right end includes a wall electrode wrapped around the upper surface and right side wall of the substrate and a solder pad at the bottom of the substrate. The right side of the substrate is thicker and difficult to perforate, and due to the large thickness, heat dissipation is difficult. For this reason, the positive electrode at the right end of the substrate wraps around the right side wall of the substrate and is led downward instead of being led out through a perforation. The wall electrode is located on the portion of the upper surface of the substrate, contacts the current expansion layer of the semiconductor layer of the LED chip (for example, the current expansion layer is provided with an upper electrode on the metal grid line, and the wall electrode contacts the upper electrode on the metal grid line), and then passes downward through the wall electrode on the right side wall of the substrate to reach the solder pad at the bottom of the substrate. The wall electrode preferably covers the entire right side wall to improve heat dissipation performance.

[0037] The LED chip of the present invention can bend the upwardly emitted light to the left when the chip is mounted horizontally, and can be used in aviation obstruction lights. The LED chip of any of the above schemes can be used in aviation obstruction lights, and the LED chip is, for example, mounted horizontally on a thermally conductive circuit board in an aviation obstruction light. It can be used in any type of aviation obstruction lights, for example, in low-intensity obstruction lights, such as type C low-intensity obstruction lights, which have a maximum light intensity at an elevation angle of 2.5°, and are required to have a divergence angle of not less than 10°. For example, it can be used in medium-intensity obstruction lights, such as type A and type B medium-intensity obstruction lights, which have a maximum light intensity at an elevation angle of 0°, and are required to have a divergence angle of 3° to 7°. For example, it can be used in high-intensity obstruction lights, such as type A and type B high-intensity obstruction lights, which have a maximum light intensity at an elevation angle of 0°, and are required to have a divergence angle of 3° to 7°.

[0038] In summary, the present invention uses the inclined upper surface of the substrate, the inclined groove, and the refractive layer to bend the light emitted by the LED to the left. The bending angle includes the inclination angle θ1 of the inclined upper surface of the substrate, the angle θ2 between the right bottom of the inclined groove and the upper surface of the substrate, and the light refraction angle θ caused by the refractive layer. 多折 The three angles restrict and complement each other. It is possible to convert the vertically upward emitted light into horizontal left light without using a packaged colloid lens or an external reflector, for example, horizontal left 0-12°, 0-10°, 2-10°, 2-20°, -1-6°, -1-2°. In addition, the electrode structure is specifically adjusted to solve the heat dissipation problem caused by the thick substrate on the right side of the LED, so that the chip has good heat dissipation and will not crack or break due to alternating hot and cold. Description of the drawings:

[0039] Figure 1 Schematic diagram of the LED chip structure of Examples 1 to 4.

[0040] Figure 2 This is a schematic diagram of the LED chip structure of Example 5.

[0041] Figure 3 This is a schematic diagram of the LED chip structure of Example 6.

[0042] Figure 4 Schematic diagram of the LED chip structure of Examples 7-9.

[0043] Figure 5 14 is a top view of the LED chip of Example 10.

[0044] Figure 6 This is an enlarged view of a single oblique groove in Example 10.

[0045] Figure 7 This is an enlarged view of the semiconductor layer, the upper electrode layer, and the dielectric layer on the left bottom of the oblique groove in Example 10.

[0046] Figure 8 It is a schematic diagram of the positive and negative electrodes of the LED chip, the top is a cross-sectional view of the substrate, and the bottom is a schematic diagram of the covering position of the perforated electrode in the perforation (the grooves and other structures on the upper surface of the substrate are not shown in the figure). Specific implementation method:

[0047] In the following, multiple inclined grooves are arranged on the inclined upper surface, and are repeatedly arranged on the inclined upper surface. In the left and right directions, the length of the inclined upper surface between two adjacent inclined grooves is less than 1 / 5 of the length of the top surface of the inclined groove (that is, the upper surface where the inclined groove is missing, which was originally the inclined upper surface of the substrate and disappeared when the substrate was etched to form the inclined groove).

[0048] The oblique groove has a right bottom surface and a left bottom surface. When the refractive layer fills the oblique groove, the left bottom surface is a plane, which is perpendicular to the right bottom surface; or, when the refractive layer does not fill the oblique groove, the left bottom surface is composed of a left bottom a and a left bottom b, where the left bottom a is at the bottom and the left bottom b is at the top, and the dividing line between the two is the upper left end of the refractive layer, the left bottom a is perpendicular to the right bottom, and the left bottom b is further bent to the left by an angle θ on the basis of the left bottom a. 多折 , that is to say, the left bottom b and the light emitted from the refractive layer are parallel, ensuring that the light at the left end of the shading layer can be emitted.

[0049] The semiconductor layer 2 deposited on the substrate includes, from bottom to top, a buffer layer 21 , an n-type layer 22 , a light-emitting layer 23 , a p-type layer 24 , and a current spreading layer 25 .

[0050] Example 1, the refractive layer is TiO2, prepared by spin coating, with a refractive index of 2.4, and the angle between the right bottom surface and the inclined surface of the substrate is 40°. Figure 1 As shown, the refractive layer does not fill up the oblique grooves and there is a gap at the top.

[0051] In this embodiment, the refractive index of TiO2 is 2.4, θ1 of the inclined upper surface of the substrate is 20°, the angle θ2 between the right bottom surface of the inclined groove and the inclined upper surface of the substrate is 40°, and the angle θ4 between the refractive layer and the right bottom surface of the inclined groove of the substrate is 20°. Therefore, the angle between the light vertically emitted from the semiconductor layer on the right bottom surface and the normal line of the top surface of the refractive layer is 20°. According to the law of refraction, when the light is emitted from the refractive layer, the angle between the light and the normal line will be expanded to 55°, which is an increase of 35 degrees, that is, θ 多折 Adding 20° of θ1 and 40° of θ2, the light is bent 95° to the left, that is, the elevation angle of the outgoing light is -5°.

[0052] Example 2, the refractive layer is TiO2, prepared by spin coating, with a refractive index of 2.4, and the angle between the right bottom surface and the inclined surface of the substrate is 30°. Figure 1 As shown, the refractive layer does not fill up the oblique grooves and there is a gap at the top.

[0053] In this embodiment, the refractive index of TiO2 is 2.4, θ1 of the inclined upper surface of the substrate is 20°, the angle θ2 between the right bottom surface of the inclined groove and the inclined upper surface of the substrate is 30°, and the angle θ4 between the refractive layer and the right bottom surface of the inclined groove of the substrate is 20°. Then, the light emitted vertically from the semiconductor layer on the right bottom surface, when emitted from the upper surface of the refractive layer, has an angle of 55° with the normal line of the upper surface of the refractive layer, that is, after being refracted by the refractive layer, the light is bent to the left by an additional θ. 多折 35°, plus 20° of θ1 and 30° of θ2, the light is bent 85° to the left, that is, the elevation angle of the outgoing light is 5°.

[0054] Example 3, the refractive layer is TiO2, prepared by spin coating, with a refractive index of 2.3, and the angle θ2 between the right bottom surface and the inclined surface of the substrate is 30°. Figure 1 As shown, the refractive layer does not fill up the oblique grooves and there is a gap at the top.

[0055] In this embodiment, the refractive index of TiO2 is 2.3, θ1 of the inclined upper surface of the substrate is 20°, the angle θ2 between the right bottom surface of the inclined groove and the inclined upper surface of the substrate is 30°, and the angle θ4 between the refractive layer and the right bottom surface of the inclined groove of the substrate is 20°. Then, the light emitted vertically from the semiconductor layer on the right bottom surface, when emitted from the upper surface of the refractive layer, has an angle of 52° with the normal line of the upper surface of the refractive layer, and the light is bent to the left by an additional angle of θ. 多折 32°. That is, the light can be bent 82°, that is, the elevation angle of the outgoing light is 8°.

[0056] Example 4, the refractive layer is TiO2, prepared by spin coating, with a refractive index of 2.3, and the angle between the right bottom surface and the inclined surface of the substrate is 30°. Figure 1 As shown, the refractive layer does not fill up the oblique grooves and there is a gap at the top.

[0057] The refractive index of TiO2 is 2.3, the angle θ1 of the inclined upper surface of the substrate is 10°, the angle θ2 between the right bottom surface of the inclined groove and the inclined upper surface of the substrate is 30°, and the angle θ4 between the refractive layer and the right bottom surface of the inclined groove of the substrate is 20°. Then the light emitted vertically from the semiconductor layer on the right bottom surface, when it is emitted from the upper surface of the refractive layer, has an angle of 52° with the normal line of the upper surface of the refractive layer, and the light is bent to the left by θ more. 多折 32°. Adding 10° of θ1 and 30° of θ2, the light is bent 72° to the left, that is, the elevation angle of the outgoing light is 18°.

[0058] It should be noted that in the above-mentioned embodiments 1 to 3, the light at the left end of the shading layer will enter the interior of the substrate due to the bending effect, and will be blocked by the semiconductor layer on the inclined surface of the substrate and cannot be emitted. Therefore, the left bottom is divided into a left bottom a and a left bottom b. The dividing line between the two is the upper left end of the refractive layer. The left bottom a is at the bottom, the left bottom b is at the top, the left bottom a is perpendicular to the right bottom, and the left bottom b is further bent to the left by an angle θ on the basis of the left bottom a. 多折 , that is to say, the left bottom b and the light emitted from the refractive layer are parallel, ensuring that the light at the left end of the shading layer can be emitted.

[0059] The refractive layer of this embodiment uses TiO2 with a very high refractive index, and the light is deflected to the left by a large amount, that is, θ 多折 On this basis, θ1 and θ2 can be appropriately reduced.

[0060] Example 5, the refractive layer is TiO2, prepared by spin coating, with a refractive index of 2.3. Based on Example 3, a light delivery layer is further provided on the refractive layer. The refraction process of light is as follows Figure 2 shown.

[0061] When using TiO2 with a high refractive index, the angle θ4 of the refractive layer cannot be too large, otherwise total reflection will occur, so the left bottom b must be set. However, the setting of the left bottom b will waste the setting area of ​​the LED semiconductor layer.

[0062] In order to reduce the waste of semiconductor layer area, this embodiment further arranges a light delivery layer on the refractive layer, and the refractive index of the light delivery layer is smaller than that of the refractive layer. For example, the light delivery layer is made of SiO2 with a refractive index of 1.45.

[0063] Take the refractive layer as TiO2, with a refractive index of 2.3 and θ4 = 20° as an example. When light is emitted from the upper surface of the light-shielding layer, the angle between it and the normal line of the upper surface of the refractive layer is 33°, that is, θ 多折 =13°. Compared with θ when no light delivery layer is provided 多折 32° (reference embodiment 3), which is reduced by 19°. Therefore, the angle at which the left bottom b is bent to the left becomes smaller, and the installation area of ​​the LED semiconductor layer increases.

[0064] After the light is refracted twice by the refractive layer and the light delivery layer, the amount of light that is finally bent to the left does not decrease, and is the same as when there is no light delivery layer.

[0065] The light delivery layer can fill the oblique groove on the inclined surface of the substrate, that is, the light is completely delivered out of the groove, such as Figure 2 Of course, the oblique grooves can also be partially filled.

[0066] Example 6, the refractive layer is a mixed layer of TiO2 and SiO2, prepared by spin coating, with a refractive index of 1.8. The refraction process of light is as follows Figure 3 As shown, the refractive layer fills the oblique grooves.

[0067] When TiO2 is used as the refractive layer, the refractive index of the refractive layer varies between 2.2 and 2.62 depending on the preparation process. By mixing TiO2 and SiO2, the refractive index of the film can be further flexibly adjusted to vary between about 1.4 and 2.2 (see "Microstructure and optical dispersion characterization of nanocomposite sol-gel TiO2-SiO2 thin films with different compositions", S. Kermadi, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 145 (2015) 145-154).

[0068] A SiO2-TiO2 mixed layer is used as the refractive layer, and SiO2 and TiO2 are uniformly mixed in the refractive layer, and the refractive index increases with the increase in the proportion of TiO2. In this embodiment, the refractive index is 1.80, θ1 of the inclined upper surface of the substrate is 20°, the angle θ2 between the right bottom surface of the oblique groove and the inclined upper surface of the substrate is 30°, and the angle θ4 between the refractive layer and the right bottom surface of the oblique groove of the substrate is 30°, that is, the refractive layer fills the groove. Therefore, the light vertically emitted from the semiconductor layer on the right bottom surface has an angle of 30° with the normal of the upper surface of the refractive layer. After refraction by the shading layer, the angle with the normal of the upper surface of the refractive layer is 64°, an increase of 34°. Adding 20° of θ1 and 30° of θ2, the light is bent 84° to the left. That is, the light finally emits at an elevation angle of 6° to the upper left.

[0069] Example 7, the refractive layer is a mixed layer of TiO2 and SiO2, prepared by spin coating, with a refractive index of 1.7. The refraction process of light is as follows Figure 4 As shown, the refractive layer does not fill up the oblique grooves.

[0070] In this embodiment, a SiO2-TiO2 mixed layer is used as the refractive layer, and SiO2 and TiO2 are uniformly mixed in the refractive layer, and the refractive index increases with the increase in the proportion of TiO2. The refractive index is 1.70, θ1 of the inclined upper surface of the substrate is 20°, the angle θ2 between the right bottom surface of the inclined groove and the inclined upper surface of the substrate is 39.5°, and the angle θ4 between the refractive layer and the right bottom surface of the inclined groove of the substrate is 30°, that is, the refractive layer does not fill the groove, and the left bottom of the groove is divided into a left bottom a and a left bottom b, the left bottom a is perpendicular to the right bottom, and the left bottom b and the right bottom are 90°+θ 多折 Angle (in this embodiment, θ 多折 is 28°, and the left base b and the right base form an angle of 118°). Therefore, the angle between the light emitted vertically from the semiconductor layer on the right bottom surface and the normal line of the upper surface of the refractive layer is 30°, and after being refracted by the refractive layer, the angle between the light and the normal line of the upper surface of the refractive layer is 58°, which increases by 28° (i.e., θ 多折 =28°). Add 20° of θ1 and 39.5° of θ2, and it bends 87.5° to the left. That is, the light finally emits at an elevation angle of 2.5° to the upper left.

[0071] Embodiment 8, except that the refractive index of the refractive layer of embodiment 7 is adjusted from 1.70 to 1.74, other settings are the same as those of embodiment 7. The refractive index is increased by increasing the proportion of TiO2 in the refractive layer.

[0072] The refractive index increases to 1.74, then θ 多折 It is 30.5°, and the light finally emits to the left at a luminous elevation angle of 0°.

[0073] Comparative Example 1

[0074] The refractive layer is TiO2, prepared by spin coating, with a refractive index of 2.4.

[0075] The refractive index of TiO2 is 2.4, the angle θ1 of the inclined upper surface of the plate is 20°, the angle θ2 between the right bottom surface and the inclined surface of the substrate is 40°, and the angle θ4 between the refractive layer and the right bottom surface is 30°. Therefore, the angle between the light emitted from the plane of the LED layer perpendicular to the LED semiconductor layer and the normal line of the upper surface of the refractive layer is 30°. After being refracted by the shading layer, the light will be totally reflected on the upper surface of the shading layer and cannot be emitted.

[0076] Example 9, except that the material of the refractive layer is adjusted as follows, other settings are the same as Example 7. The refractive layer is a mixed layer of TiO2 and SiO2, prepared by spin coating, and the refractive index of the refractive layer in different oblique grooves gradually changes from 2.0 to 1.7 from the left side to the right side of the LED chip, so that the final emitting elevation angle of the light gradually increases from the left side to the right side of the LED chip.

[0077] Embodiment 10: Based on any of the above embodiments, this embodiment further adds an upper electrode layer of the LED, that is, the LED chip includes an upper electrode layer, such as a metal grid electrode, which is in direct contact with the current expansion layer 25 of the LED semiconductor layer to deliver positive current to the LED. Figure 5-7 The cathode current of the LED is transmitted to the n-type layer 22 through the cathode electrode, and the n-type layer 22 of the entire LED chip is connected and shared.

[0078] On the inclined upper surface of the substrate 1 and on the left and right bottoms of the inclined grooves, the LED semiconductor layer 2 is deposited, and the upper electrode 5 is further deposited.

[0079] The shape of the upper electrode is specially designed to solve the problem that the right side of the substrate is thicker and heat dissipation is difficult on the right side. Figure 5 , the left and right sides of the substrate are divided into a conventional heat dissipation zone and an enhanced heat dissipation zone. The enhanced heat dissipation zone refers to an area where the heat dissipation capacity is enhanced relative to the conventional heat dissipation zone. In this embodiment, the heat dissipation is enhanced by increasing the width of the gate line. The enhanced heat dissipation zone is located on the right side of the substrate. The length is calculated from the right edge of the substrate and accounts for 2 / 3 of the total length in the left and right directions. The electrode gate line on the left bottom wall of the oblique groove of the substrate is a thick gate line, whether in the conventional heat dissipation zone or in the enhanced heat dissipation zone; the electrode on the inclined upper surface and the electrode on the right bottom wall of the oblique groove are thick gate lines when they are in the enhanced heat dissipation zone, and are thin gate lines when they are in the conventional heat dissipation zone. The LED semiconductor layer attached to the inclined upper surface and the right bottom wall of the oblique groove is the main light-emitting area that emits light to the left. If the gate line is set thick, although the heat dissipation is good, the light blocking is serious. Therefore, it is only set thicker in the enhanced heat dissipation zone; and the semiconductor layer on the left bottom wall of the oblique groove is difficult to emit light to the left, so a thick gate line is set to improve the heat dissipation performance. The width of the thick gate line is greater than that of the thin gate line; preferably, the width of the thick gate line is 50 to 150 microns, and the width of the thin gate line is 10 to 80 microns.

[0080] In this embodiment, the left bottom wall is a non-luminous area. Figure 7 Schematic diagram of the semiconductor layer structure on the left bottom wall. Figure 6 , 7, cutting grooves 3 are provided at the upper and lower ends of the left bottom wall. From the top to the bottom of the semiconductor layer 2, the cutting grooves cut off the current expansion layer 25, the P-type layer 24, and the light-emitting layer 23, and stay on the n-type layer 22. And on the LED semiconductor layer area located in the two cutting grooves at the upper and lower ends of the left bottom wall, and in the cutting grooves, sandwiched between the semiconductor layer and the upper electrode layer, a SiO2 dielectric layer 4 is provided to block the power supply current from reaching this area, and only supply it to the right bottom wall and the inclined upper surface, which helps to improve the luminous intensity of the right bottom wall and the inclined upper surface. Therefore, except on the left bottom wall, the upper electrode in other areas (on the right bottom wall and the inclined upper surface) directly contacts the semiconductor layer; and on the left bottom wall, the upper electrode 5 is provided on the SiO2 dielectric layer 4, thereby being insulated from the semiconductor layer 2.

[0081] Embodiment 11, as Figure 8 As shown, the LED chip has positive and negative electrodes.

[0082] The cathode is at the left end of the substrate. The cathode includes a perforated electrode in the perforation and a pad at the bottom of the perforation. The perforated electrode covers the left and right walls of the perforation, not exceeding 2 / 3 of the circumference of the left wall and 2 / 3 of the circumference of the right wall, and in this embodiment, 1 / 2 of the left wall and 1 / 2 of the right wall. The covering position of the perforated electrode on the left and right walls is centered on the midline of the left and right side walls of the LED chip, and is equal in width from the top to the bottom of the hole.

[0083] The positive electrode is at the right end of the substrate. The positive electrode at the right end includes a wall electrode that wraps around the upper surface and right side wall of the substrate and a pad at the bottom of the substrate. The wall electrode is located on the upper surface of the substrate, contacts the current expansion layer of the semiconductor layer of the LED chip (for example, the current expansion layer is provided with a metal grid line upper electrode, and the wall electrode contacts the metal grid line upper electrode), and then passes downward through the wall electrode on the outer surface of the right side wall of the substrate to reach the pad at the bottom of the substrate. The wall electrode covers the entire right side wall.

[0084] Embodiment 12: In this embodiment, the LED chip of embodiment 7 is used in an aviation obstruction light. The aviation obstruction light is a C-type low-intensity aviation obstruction light, and the maximum light intensity is at an elevation angle of 2.5°. The LED chip is mounted horizontally on a heat dissipation circuit board.

[0085] Embodiment 13: This embodiment uses the LED chip of embodiment 8 in an aviation obstruction light. The aviation obstruction light is a medium-intensity aviation obstruction light of type A or type B, or a high-intensity aviation obstruction light of type A or type B, with the maximum light intensity at an elevation angle of 0°. The LED chip is mounted horizontally on a heat dissipation circuit board.

Claims

1. An LED chip, comprising a substrate, and a semiconductor layer located on the substrate, wherein the semiconductor layer comprises an n-type layer, a light-emitting layer and a p-type layer arranged in sequence from bottom to top; characterized in that: The upper surface of the substrate is an inclined upper surface, the thickness of the substrate increases linearly from left to right, and the angle between the inclined upper surface of the substrate and the horizontal plane is θ1; a plurality of inclined grooves are arranged in the inclined upper surface of the substrate, the inclined grooves have a right bottom surface and a left bottom surface, the two are perpendicular to each other at the intersection, the inclined grooves are triangular prism-shaped or quasi-triangular prism-shaped, and the angle between the right bottom surface of the inclined groove and the upper surface of the substrate is θ2; a refractive layer with a high refractive index greater than 1.4 is arranged on the semiconductor layer in the inclined groove, the refractive layer gradually becomes thicker from the upper right starting point of the inclined groove of the substrate to the lower left, the angle between the bottom surface and the top surface of the light shielding layer is θ4, and the refractive layer causes the light emitted from the LED semiconductor layer on the right bottom to deviate to the left by θ due to light refraction when passing through the refractive layer. 多折 The degree of leftward deviation of the output light emitted by the LED semiconductor layer on the right bottom surface of the inclined groove relative to the plane where the lower bottom surface of the substrate is located is θ1+θ2+θ 多折 ; The semiconductor layer is arranged on the inclined upper surface of the substrate, the right bottom surface of the inclined groove and the left bottom surface of the inclined groove.

2. The LED chip according to claim 1, characterized in that: Adjacent oblique grooves on the upper surface of the substrate are discontinuously arranged with the remaining inclined upper surface of the substrate therebetween. In the left-right direction, the length of the inclined upper surface between two adjacent oblique grooves is less than 1 / 5 of the length of the top surface of the oblique groove.

3. The LED chip according to claim 1, characterized in that: The refractive layer fills up the oblique groove, and the refractive layer and the oblique groove are in a triangular prism shape.

4. The LED chip according to claim 1, characterized in that: The refractive layer is not filled with the oblique groove, which is a triangular prism-like shape. The left bottom surface of the oblique groove is composed of the left bottom a and the left bottom b. The left bottom a is at the bottom and the left bottom b is at the top. The dividing line between the two is the upper left end of the refractive layer. The left bottom a is perpendicular to the right bottom surface. The left bottom b is further bent to the left at an angle θ based on the left bottom a. 多折 .

5. The LED chip according to claim 1, characterized in that: The material of the refractive layer is TiO2, or a mixture of TiO2 and SiO2.

6. The LED chip according to claim 4, characterized in that: A light delivery layer is disposed on the refractive layer, and the refractive index of the light delivery layer is lower than that of the refractive layer.

7. The LED chip according to claim 1, characterized in that: The LED chip further includes an upper electrode layer arranged above the semiconductor layer, and the upper electrode layer is a metal electrode grid line; the substrate is divided into a conventional heat dissipation area and an enhanced heat dissipation area on the left and right sides, and the enhanced heat dissipation area is located on the right side of the substrate; the electrode grid line on the left bottom surface of the oblique groove of the substrate is a thick grid line, whether in the conventional heat dissipation area or in the enhanced heat dissipation area; the upper electrode layer on the inclined upper surface and the upper electrode layer on the right bottom surface of the oblique groove are thick grid lines when they are in the enhanced heat dissipation area, and are thin grid lines when they are in the conventional heat dissipation area.

8. The LED chip according to claim 1, characterized in that: The left bottom surface is a non-luminous area. Cutting grooves are provided at the upper and lower ends of the left bottom surface. From the top to the bottom of the semiconductor layer, the cutting grooves at least cut through the P-type layer and the light-emitting layer, and stay on the N-type layer or in the N-type layer; on the LED semiconductor layer area located in the two cutting grooves at the upper and lower ends of the left bottom surface, and in the cutting grooves, sandwiched between the semiconductor layer and the upper electrode layer, a dielectric layer is provided to block the power current from reaching this area.

9. The LED chip according to claim 1, characterized in that: After the outgoing light finally emitted by the LED semiconductor layer on the right bottom surface of the inclined groove is shifted to the left, the angle between this part of the light and the horizontal plane, that is, the light elevation angle, is -5 to 30 degrees.

10. An aviation obstruction light, comprising a horizontally mounted LED chip, characterized in that: The LED chip adopts the LED chip of any one of claims 1 to 9, so that the vertically upward emitted light is bent toward the horizontal direction.

Images