An LED chip and an aviation obstruction light using the same

Abstract

This invention relates to an LED chip and an aviation obstruction light using the same. The upper surface of the LED chip substrate is inclined at an angle of θ1. Multiple oblique grooves are provided within the inclined upper surface of the substrate, with the right bottom surface of each groove forming an angle of θ2 with the upper surface of the substrate. A high-refractive-index refractive layer is provided on the semiconductor layer within the oblique grooves. This refractive layer causes light rays emitted vertically from the LED semiconductor layer on the right bottom surface to be deflected to the left by light refraction at an angle θ2. 多折 The LED chip uses θ1+θ2+θ 多折 Even when LED chips are mounted horizontally, the light emitted from the semiconductor layer of the LED chip can be bent at a large angle in the horizontal direction without the need for encapsulated lenses and external reflectors. At the same time, by optimizing the electrode structure, the chip will not have difficulty in heat dissipation or crack due to the thicker right side of the substrate.

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, so 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 encapsulating glue of the encapsulated lamp bead can be made into a lens shape, and the lens of the lens encapsulating glue is used to adjust the light-emitting angle value to be horizontal. An external reflector can also be assisted in setting, and a metal reflector is set outside the LED lamp bead to further adjust the light-emitting direction to be horizontal.

[0004] Making the encapsulating glue into a lens shape requires a thick encapsulating colloid, 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 lamp, adding a metal reflector outside the LED lamp bead can adjust the light-emitting direction to be horizontal, but on the one hand, it will increase the complexity of the lamp, increase the material cost and installation labor cost of the lamp, and on the other hand, the metal reflector will also occupy a large amount of installation space. Summary of the Invention:

[0005] The present invention proposes 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-emitting 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 and 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 upper electrode, which contacts 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 inclined upward. The 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 toward 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 even more preferably 10 - 20°, such as 20°. If θ1 is too small, it is difficult to effectively bend the emitted light of the LED toward 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 - hand 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 angle between the right bottom surface of the inclined groove and the inclined upper surface of the substrate is θ2. The right bottom surface of the inclined groove is used to bend the emitted light of the LED toward the horizontal direction. 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 - hand side 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, it can ensure a higher intensity of the light emitted to the left.

[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 part 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 contacting 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 easily occurs and it is difficult for the light to exit. The angle 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, with the refractive index varying between 1.4 and 2.2. The refractive layer is preferably prepared by spin - coating, 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 spin - coating 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 occurs. 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, and 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 the right bottom of the inclined groove, an LED semiconductor layer is deposited, and then 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 blocking 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] <LED Chip Light Emission Control>

[0026] The light emitted from the left bottom wall of the inclined groove of the substrate is emitted to the right and is blocked by the right bottom wall and is difficult to emit. 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 the top to the bottom of the semiconductor layer, the cutting grooves at least cut off the current spreading layer, the P-type layer, and the light-emitting layer and stay 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-emitting 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, in the case of no special description, this is the case.

[0028] Alternatively, the inclined groove can have different structures, such as different angles between the right side wall and the inclined upper surface, to obtain more diverse and precisely controlled emission angles of the emitted light through different θ2 angles. Generally, LED light emission, in addition to the angle precisely adjusted in this application, also emits residual light in other directions. The light is mainly emitted at the precisely adjusted angle, but has a certain diffusion angle. To more precisely control the diffusion angle, the angle between the right side wall and the inclined upper surface of the inclined groove can be adjusted so that different grooves correspond to different emission angles of the emitted light. For example, the emission angle can be divided into twelve equal parts, each corresponding to an elevation angle of 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, and 11° respectively. For example, the elevation angle of the emitted light is divided into 22 parts, with 2.5° accounting for ten parts, and the other twelve parts corresponding to 0°, 1°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, and 15° respectively. In this way, the 2.5° direction has the largest light-emitting area (the light-emitting angle of the ten grooves is 2.5°, while the other angles have only one groove), which is the main light-emitting angle. There is also a precise light-emitting distribution in the remaining angles, that is, the light emission of the remaining angles other than 2.5° is precisely enhanced.

[0029] Alternatively, the inclined grooves may all have the same structure, but the refractive index of the refractive layer within each groove may be changed, i.e., by adjusting θ. 多折 This allows for a wider variety of exit ray elevation angles. For example, the refractive index can increase sequentially (e.g., uniformly) from right to left, making θ... 多折 By gradually increasing the elevation angle, the final elevation angle of the light emitted from the bottom right of the leftmost slanted groove of the LED chip becomes 0° (or -1°), while the final elevation angle of the light emitted from the bottom right of the rightmost slanted groove of the LED chip becomes 11° (or 6°). Thus, the chip's emission elevation angle can be more precisely controlled within a certain angular range.

[0030] Alternatively, the refractive index of the inclined groove structure (e.g., the angle between the right side wall of the inclined groove and the inclined upper surface) and the refractive index of the refractive layer within the inclined groove can be adjusted simultaneously, so that the refractive indices of the inclined groove structure on the inclined upper surface and the refractive layer within the inclined groove are different from left to right. This allows the chip's emission elevation angle to be precisely controlled within a specific angular range. For example, a precise emission elevation angle control between 2 and 10° is used for type B low-intensity obstruction lights; a precise control between 2 and 20° is used for type C low-intensity obstruction lights; and a precise control between -1 to 6° or -1 to 2° is used for medium-intensity and high-intensity obstruction lights.

[0031] The upper surface of the chip can be further covered with a passivation protection layer. For example, the semiconductor layers 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 provided 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, and is dispersed to the semiconductor layer by the upper electrode, and then汇总到负电极(例如经由n型层汇总到负电极)后再次进入电源。(此句中“汇总到负电极(例如经由n型层汇总到负电极)”翻译为“aggregated to the negative electrode (for example, aggregated to the negative electrode via the n-type layer)”,但感觉“汇总到”表述不太准确,可根据实际情况调整更合适的表达,比如“汇聚到”等,这里先按原文翻译)and then enters the power source again after aggregating to the negative electrode (for example, aggregating to the negative electrode via the n-type layer).

[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 to serve as the negative electrode of the LED. The negative electrode includes a through-hole electrode in the perforation and a pad at the bottom of the perforation; the through-hole electrode is a mature electrode setting method for the LED chip, and in this application, the thickness of the substrate at the left end is the same as the thickness of the conventional thinned LED substrate (about 100 microns), making it easy to achieve the perforation.

[0035] Preferably, the above-mentioned through-hole electrode does not completely fill the perforation, but covers the left side wall and the right side wall 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, such as 20 - 60 times per minute, such as more than 60 flashes per minute, such as 80 times per minute. Alternating heat and cold can 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 in the front-rear direction (perpendicular to the left-right direction, into the paper). Setting the through-hole electrode on the left side wall and the right side wall, the thermal expansion direction is along the paper direction rather than the left-right direction, and no left-right expansion force will be generated at the tip of the left end, which will not promote the fracture of the left end.

[0036] Preferably, the positive electrode at the right end includes a wall electrode surrounding the upper surface and right side wall of the substrate and a pad at the bottom of the substrate. The right side of the substrate is thicker, making through-hole drilling difficult and heat dissipation challenging. Therefore, the positive electrode at the right end of the substrate is led downwards around the right side wall of the substrate instead of being led out through a hole. The portion of the wall electrode located on the upper surface of the substrate contacts the current spreading layer of the semiconductor layer of the LED chip (e.g., the current spreading layer has a metal gate electrode on it, and the wall electrode contacts the metal gate electrode), and then extends downwards through the wall electrode on the right side wall of the substrate to the 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 this invention can bend upward-emitting light to the left when the chip is horizontally mounted, and can be used in aviation obstruction lights. The LED chip of any of the above-described embodiments can be used in aviation obstruction lights, for example, the LED chip is horizontally mounted on a heat-conducting circuit board inside the aviation obstruction light. It can be used in any type of aviation obstruction light, 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 require 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 require 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 require a divergence angle of 3° to 7°.

[0038] In summary, this invention combines the use of an inclined upper surface of the substrate, an oblique groove, and a light-refractive layer to bend the light emitted by the LED to the left. The bending angle includes the tilt angle θ1 of the inclined upper surface of the substrate, the angle θ2 between the right bottom of the oblique groove and the upper surface of the substrate, and the light refraction angle θ caused by the light-refractive layer. 多折 The sum of these three angles, mutually constraining and complementing each other, allows for the conversion of vertically upward emitted light into a horizontal leftward direction without the use of encapsulated colloidal lenses or external reflectors. For example, horizontal leftward angles of 0–12°, 0–10°, 2–10°, 2–20°, -1–6°, and -1–2° are possible. Furthermore, to address the heat dissipation difficulties caused by the thicker substrate on the right side of the LED, the electrode structure was specifically adjusted, resulting in good heat dissipation of the chip and preventing cracks or breakage due to alternating hot and cold temperatures. Attached image description:

[0039] Figure 1 These are schematic diagrams of the LED chip structures in Examples 1 to 4.

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

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

[0042] Figure 4 This is a schematic diagram of the LED chip structure in Examples 7-9.

[0043] Figure 5 This is a top view of the LED chip in 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, upper electrode layer, and dielectric layer on the left bottom of the inclined groove in Example 10.

[0046] Figure 8 This is a schematic diagram of the positive and negative electrodes of an LED chip. The top is a cross-sectional view of the substrate, and the bottom is a schematic diagram of the coverage position of the through-hole electrode inside the through hole (the grooves and other structures on the upper surface of the substrate are not shown in the figure). Detailed implementation method:

[0047] In the following text, multiple oblique grooves are provided on the inclined upper surface, and are repeatedly provided on the inclined upper surface. 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 (i.e. the upper surface missing from the oblique groove, which was originally the inclined upper surface of the substrate, but disappeared when the substrate was etched to form the oblique groove).

[0048] The inclined groove has a right bottom surface and a left bottom surface. When the refractive layer fills the inclined groove, the left bottom surface is a plane, perpendicular to the right bottom surface; or, when the refractive layer does not fill the inclined groove, the left bottom surface is composed of left bottom a and left bottom b, with left bottom a at the bottom and left bottom b at the top. The dividing line between the two is the upper left end of the refractive layer. Left bottom a is perpendicular to the right bottom, and left bottom b is further bent to the left at an angle θ based on left bottom a. 多折 In other words, the light from the left bottom b and the light emitted from the refractive layer are parallel, ensuring that the light from the left end of the light-blocking layer can be emitted.

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

[0050] Example 1: The refractive layer is TiO2, prepared by spin coating, with a refractive index of 2.4. The angle between the right bottom surface and the beveled surface of the substrate is 40°. The light refraction process is as follows... Figure 1 As shown, the refractive layer does not fill the slanted groove, and there is a gap at the top.

[0051] In this embodiment, the refractive index of TiO2 is 2.4, the angle 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 vertically emitted light from the semiconductor layer on the right bottom surface and the normal of the top surface of the refractive layer is 20°. According to the law of refraction, when the light exits from the refractive layer, the angle with the normal will increase to 55°, an increase of 35 degrees, i.e., θ 多折 The angle is 35°. Adding 20° to θ1 and 40° to θ2, the light ray bends 95° to the left, meaning the elevation angle of the outgoing ray 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 bevel of the substrate is 30°. The light refraction process is as follows... Figure 1 As shown, the refractive layer does not fill the slanted groove, and there is a gap at the top.

[0053] In this embodiment, the refractive index of TiO2 is 2.4, the angle 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°. Therefore, light rays vertically emitted from the semiconductor layer on the right bottom surface will form an angle of 55° with the normal to the upper surface of the refractive layer when emitting light from the upper surface of the refractive layer. That is, after refraction by the refractive layer, the light rays bend to the left by an additional θ. 多折 35°, plus 20° of θ1 and 30° of θ2, the light ray bends 85° to the left, that is, the elevation angle of the outgoing light ray is 5°.

[0054] Example 3: The refractive layer is TiO2, prepared by spin coating, with a refractive index of 2.3. The angle θ2 between the right bottom surface and the inclined surface of the substrate is 30°. The refraction process of light is as follows... Figure 1 As shown, the refractive layer does not fill the slanted groove, and there is a gap at the top.

[0055] In this embodiment, the refractive index of TiO2 is 2.3, the angle 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°. Therefore, the light rays vertically emitted from the semiconductor layer on the right bottom surface, when emitted from the upper surface of the refractive layer, form an angle of 52° with the normal to the upper surface of the refractive layer, meaning the light rays are bent to the left by an additional θ. 多折 32°. This means that the light can be bent by 82°, that is, the elevation angle of the emitted 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 bevel of the substrate is 30°. The light refraction process is as follows... Figure 1 As shown, the refractive layer does not fill the slanted groove, and there is a gap at the top.

[0057] The refractive index of TiO2 is taken as 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 is 20°. Then, a ray of light vertically emitted from the semiconductor layer on the right bottom surface will, when emitted from the upper surface of the refractive layer, form an angle of 52° with the normal to the upper surface of the refractive layer, meaning the ray bends to the left by an additional θ. 多折 32°. Adding 10° to θ1 and 30° to θ2, the light ray bends 72° to the left, meaning the elevation angle of the outgoing ray is 18°.

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

[0059] In this embodiment, the refractive layer uses TiO2 with an extremely high refractive index, resulting in a significant leftward shift of light, i.e., θ. 多折 If the value is large, then 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 added to the refractive layer. The light refraction process is as follows... Figure 2 As shown.

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

[0062] To reduce wasted semiconductor layer area, this embodiment further incorporates a light delivery layer on the refractive layer. The refractive index of the light delivery layer is lower than that of the refractive layer. For example, the light delivery layer may be made of SiO2 with a refractive index of 1.45.

[0063] Taking TiO2 as the refractive layer with a refractive index of 2.3 and θ4 = 20° as an example, when light exits from the upper surface of the light-shielding layer, the angle between the light and the normal to the upper surface of the refractive layer is 33°, i.e., θ4 = 20°. 多折 =13°. Compared to θ without a light delivery layer. 多折 The angle of the left bottom b bending to the left is reduced by 19° to 32° (refer to Example 3), thus the angle of the left bottom b bending to the left is smaller, and the area of ​​the LED semiconductor layer is increased.

[0064] After the light passes through the refractive layer and the light delivery layer twice, the amount of light that bends to the left does not decrease and remains the same as when there is no light delivery layer.

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

[0066] Example 6: The refractive layer is a mixture 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 slanted groove.

[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. However, by using a mixture of TiO2 and SiO2, the refractive index of the film can be further adjusted flexibly, varying between approximately 1.4 and 2.2 (refer to "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 hybrid layer is used as the refractive layer, in which SiO2 and TiO2 are uniformly mixed. The refractive index increases with the higher proportion of TiO2. In this embodiment, the refractive index is 1.80, θ1 of the inclined upper surface of the substrate is 20°, θ2 of the angle between the right bottom surface of the inclined groove and the inclined upper surface of the substrate is 30°, and θ4 of the angle between the refractive layer and the right bottom surface of the inclined groove is 30°, meaning the refractive layer fills the groove. Therefore, the angle between the vertically emitted light from the semiconductor layer on the right bottom surface and the normal of the upper surface of the refractive layer is 30°. After refraction by the light-shielding layer, the angle between the light and the normal of the upper surface of the refractive layer is 64°, an increase of 34°. Adding the 20° of θ1 and the 30° of θ2, the light bends 84° to the left. That is, the final emission angle of the light is 6°, emitted to the upper left.

[0069] Example 7: The refractive layer is a mixture 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 completely fill the slanted groove.

[0070] In this embodiment, a SiO2-TiO2 mixed layer is used as the refractive layer. The refractive layer uniformly mixes SiO2 and TiO2, and the refractive index increases with the increase of the proportion of TiO2. The refractive index is set to 1.70. The angle 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 is 30°. That is, the refractive layer does not fill the groove. The left bottom of the groove is divided into left bottom a and left bottom b. Left bottom a is perpendicular to the right bottom, and left bottom b forms a 90° + θ with the right bottom. 多折 Angle (θ in this embodiment) 多折 The angle is 28°, and the left bottom (b) and right bottom form an angle of 118°. Therefore, the angle between the vertically emitted light from the semiconductor layer on the right bottom surface and the normal to the upper surface of the refractive layer is 30°. After refraction by the refractive layer, the angle between the light and the normal to the upper surface of the refractive layer is 58°, an increase of 28° (i.e., θ). 多折 (28°). Adding 20° of θ1 and 39.5° of θ2, it bends 87.5° to the left. That is, the light finally shines out at an elevation angle of 2.5° to the upper left.

[0071] Example 8 is identical to Example 7 except that the refractive index of the refracting layer in Example 7 is adjusted from 1.70 to 1.74. The refractive index is increased by increasing the proportion of TiO2 in the refracting layer.

[0072] If the refractive index is increased to 1.74, then θ 多折 The angle is 30.5°, and the light eventually shines to the left at an 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 taken as 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 light rays emitted from the plane perpendicular to the LED semiconductor layer of the LED layer make an angle of 30° with the normal of the upper surface of the refractive layer. After being refracted by the light-shielding layer, the light rays will undergo total internal reflection at the upper surface of the light-shielding layer and cannot be emitted.

[0076] Example 9 is identical to Example 7 except for the following adjustments to the material of the refractive layer. The refractive layer is a mixture of TiO2 and SiO2, prepared by spin coating. The refractive index of the refractive layer in different inclined grooves gradually changes from 2.0 to 1.7 from the left to the right side of the LED chip. This results in a gradual increase in the final emission angle of the light from the left to the right side of the LED chip.

[0077] Example 10: This example, based on any of the preceding examples, further adds an upper electrode layer to the LED. Specifically, the LED chip includes an upper electrode layer, such as a metal gate line electrode, which directly contacts the current spreading layer 25 of the LED semiconductor layer to supply positive current to the LED. Figure 5-7 Schematic diagram. The negative current of the LED is transmitted to the n-type layer 22 through the negative electrode. The n-type layer 22 of the entire LED chip is connected and shared.

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

[0079] The shape of the upper electrode is specially designed to solve the problem of the substrate being thicker on the right side, making heat dissipation difficult on the right side. (Reference) Figure 5 The substrate is divided into a conventional heat dissipation area and an enhanced heat dissipation area on the left and right sides. The enhanced heat dissipation area refers to the region where heat dissipation capacity is enhanced compared to the conventional heat dissipation area. In this embodiment, heat dissipation is enhanced by increasing the width of the grid lines. The enhanced heat dissipation area is located on the right side of the substrate, and its length, measured from the right edge of the substrate, accounts for 2 / 3 of the total length in the left and right directions. The electrode grid lines on the left bottom wall of the inclined groove of the substrate are coarse grid lines, regardless of whether they are in the conventional heat dissipation area or the enhanced heat dissipation area. The electrodes on the inclined upper surface and the electrodes on the right bottom wall of the inclined groove are coarse grid lines when they are in the enhanced heat dissipation area, and fine grid lines when they are in the conventional heat dissipation area. The LED semiconductor layer attached to the inclined upper surface and the right bottom wall of the inclined groove is the main light-emitting area that emits light to the left. If the grid lines are set to be thick, although the heat dissipation is good, the light will be severely blocked. Therefore, the grid lines are set to be thicker only in the enhanced heat dissipation area. As for the semiconductor layer on the left bottom wall of the inclined groove, the light is difficult to emit to the left, so thick grid lines are set to improve the heat dissipation performance. The width of the coarse gate line is greater than the width of the fine gate line; preferably, the width of the coarse gate line is 50 to 150 micrometers and the width of the fine gate line is 10 to 80 micrometers.

[0080] In this embodiment, the left bottom wall is a non-light-emitting area. Figure 7 This is a schematic diagram of the semiconductor layer structure on the bottom left wall. (Reference) Figure 6 , 7Cutting grooves 3 are provided at the upper and lower ends of the left bottom wall. These grooves cut through the current extension layer 25, the P-type layer 24, and the light-emitting layer 23 from the top to the bottom of the semiconductor layer 2, stopping on the n-type layer 22. Furthermore, on the LED semiconductor layer area located within the two cutting grooves at the upper and lower ends on the left bottom wall, and within the cutting grooves, sandwiched between the semiconductor layer and the upper electrode layer, a SiO2 dielectric layer 4 is provided. This layer blocks the power supply current from reaching this area, supplying it only to the right bottom wall and the inclined upper surface, thus helping 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; while on the left bottom wall, the upper electrode 5 is disposed on the SiO2 dielectric layer 4, thereby insulating it from the semiconductor layer 2.

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

[0082] The negative electrode is located at the left end of the substrate. The negative electrode includes a through-hole electrode within the through-hole and a pad at the bottom of the through-hole. The through-hole electrode covers the left and right walls of the through-hole, not exceeding 2 / 3 of the circumference of the left and right walls respectively; in this embodiment, it covers 1 / 2 of the left and 1 / 2 of the right walls. The coverage position of the through-hole electrode on the left and right walls is centered on the centerline of the left and right side walls of the LED chip, with equal width from the top to the bottom of the hole.

[0083] The positive electrode is located at the right end of the substrate. The positive electrode at the right end includes a wall electrode surrounding the upper surface and right side wall of the substrate, and a pad at the bottom of the substrate. The portion of the wall electrode located on the upper surface of the substrate contacts the current spreading layer of the LED chip's semiconductor layer (e.g., a metal gate electrode is provided on the current spreading layer, and the wall electrode contacts the metal gate electrode), then extends downwards 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] Example 12: This example uses the LED chip from Example 7 in an aviation obstruction light. The aviation obstruction light is a C-type low-intensity aviation obstruction light with a maximum intensity at an elevation angle of 2.5°. The LED chip is horizontally mounted on a heat dissipation circuit board.

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

Claims

1. An LED chip, comprising a substrate and a semiconductor layer disposed on the substrate, the semiconductor layer comprising an n-type layer, a light-emitting layer and a p-type layer disposed sequentially from bottom to top; characterized in that, The substrate has an inclined upper surface, with its thickness increasing linearly from left to right. The angle between the inclined upper surface and the horizontal plane is θ1. Multiple inclined grooves are formed within the inclined upper surface, each groove having a right bottom surface and a left bottom surface, which are perpendicular to each other at their intersection. The grooves are triangular prisms or quasi-triangular prisms, and the angle between the right bottom surface of the groove and the upper surface of the substrate is θ2. A high-refractive-index refractive layer with a refractive index greater than 1.4 is formed on the semiconductor layer within the inclined grooves. The refractive layer gradually thickens from the upper right of the inclined groove towards the lower left. The angle between the bottom and top surfaces of the light-shielding layer is θ4. The refractive layer causes light emitted from the LED semiconductor layer on the lower right to be deflected to the left by light refraction due to θ when passing through it. 多折 The emitted light from the LED semiconductor layer on the right bottom surface of the inclined groove is offset to the left by an angle of θ1+θ2+θ relative to the plane containing the bottom surface of the substrate. 多折 The semiconductor layer is disposed 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, The adjacent inclined grooves on the upper surface of the substrate are not discontinuously arranged, with the remaining inclined upper surface of the substrate in between. 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.

3. The LED chip according to claim 1, characterized in that, The light-reflecting layer fills the oblique groove, and both the light-reflecting layer and the oblique groove are triangular prisms.

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

5. The LED chip according to claim 1, characterized in that, The refractive layer material 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 smaller 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 disposed above the semiconductor layer, the upper electrode layer being 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, the enhanced heat dissipation area being located on the right side of the substrate; the electrode grid line on the left bottom surface of the inclined groove of the substrate is a coarse grid line, regardless of whether it is in the conventional heat dissipation area or 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 inclined groove are coarse grid lines when they are in the enhanced heat dissipation area and fine grid lines when they are in the conventional heat dissipation area.

8. The LED chip according to claim 1, characterized in that, The bottom left surface is a non-light-emitting area. Cutting grooves are provided at the top and bottom of the bottom left surface. From the top to the bottom of the semiconductor layer, the cutting grooves cut through at least the P-type layer and the light-emitting layer, and stop on or inside the N-type layer. On the LED semiconductor layer area located in the two cutting grooves at the top and bottom of the bottom left 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 supply current from reaching this area.

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

10. An aviation obstruction light, comprising horizontally mounted LED chips, characterized in that, The LED chip is any one of the LED chips described in claims 1-9, which causes the vertically upward emitted light to bend in the horizontal direction.

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