Fine spaced LED array with larger vertical field of view, automotive lighting system and method of manufacture

Abstract

A finely spaced LED array, an automotive lighting system, and a method of manufacture are described herein. The LED lighting system includes an array of rows and columns of LEDs, wherein the spacing between adjacent LEDs in the array is less than 50 microns. The array comprises at least five rows of LEDs. A plurality of first conductive connectors electrically couple the LEDs in the first four of the five rows in series. A plurality of second conductive connectors electrically couple the LEDs in the fifth one of the five rows in parallel to the LEDs in the fourth one of the five rows.

Description

Background Technology

[0001] Adaptive high beam (ADB) is a headlight system that, from the driver's perspective, automatically emits less light in some areas of the road and more light in others. For example, the car can detect objects on or near the road and adjust the beam so that pedestrians, animals, and other objects are well illuminated without reducing the visibility of other drivers on the road.

[0002] ADB (Adaptive Beam Delay) technology is becoming increasingly popular and important in the automotive industry because it enhances safety and showcases a brand's technological prowess. ADB headlights typically comprise an LED array with a conventional spacing of 500µm or greater between adjacent LEDs. Utilizing this conventional spacing, pre-optics, such as silicone pre-optics, are typically required to increase luminous efficiency and / or alter the light distribution of the LED array. Due to the high tolerance requirements of LED arrays and the specialized manufacturing processes typically used to produce them, the cost of pre-optics used in ADB headlights can be quite high. Summary of the Invention

[0003] This document describes a finely spaced LED array, an automotive lighting system, and a method for manufacturing it. The LED lighting system includes an array of LED rows and columns, wherein the spacing between adjacent LEDs in the array is less than 50 micrometers. The array includes at least 5 rows of LEDs. A plurality of first conductive connectors electrically couple the LEDs in the first 4 of the 5 rows in series. A plurality of second conductive connectors electrically couple the LEDs in the fifth row of the 5 rows in parallel to the LEDs in the fourth row of the 5 rows. Attached Figure Description

[0004] A more detailed understanding can be obtained through the following description given with examples and accompanying figures, wherein: Figure 1A This is a top view of an example LED array used in LED headlight systems, such as ADB headlight systems; Figure 1B This is a top view of another example LED array used in LED headlight systems, such as ADB headlight systems; Figure 2 This is a top view of an example finely spaced LED array used in an ADB headlight system; Figure 3 This is an example of a finely spaced LED array (such as...) Figure 2 Circuit diagram of a finely spaced LED array; Figure 4 This is a top view of another example of a finely spaced LED array used in an ADB headlight system; Figure 5 It is a finely spaced LED array (such as) Figure 4 Circuit diagram of a finely spaced LED array; Figure 6 This is a diagram of an example vehicle headlight system; and Figure 7 This is a flowchart of an example method for manufacturing a finely spaced LED array. Detailed Implementation

[0005] Examples of different light illumination systems and / or light-emitting diode (“LED”) implementations will be described more fully below with reference to the accompanying drawings. These examples are not mutually exclusive, and features found in one example may be combined with features found in one or more other examples to achieve additional implementations. Therefore, it will be understood that the examples shown in the drawings are provided for illustrative purposes only and are not intended to limit this disclosure in any way. The same reference numerals refer to the same elements throughout the text.

[0006] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms may be used to distinguish one element from another. For example, without departing from the scope of the invention, a first element may be referred to as a second element, and a second element may be referred to as a first element. As used herein, the term "and / or" may include any and / or all combinations of one or more of the associated listed items.

[0007] It will be understood that when an element such as a layer, region, or substrate is referred to as "on" or "extending" to another element, it can be directly on or directly extended to the other element, or there may be intermediate elements present. Conversely, when an element is referred to as "directly on" or "directly extended" to another element, there may be no intermediate elements present. It will also be understood that when an element is referred to as "connected" or "coupled" to another element, it can be directly connected or coupled to the other element and / or connected or coupled to the other element via one or more intermediate elements. Conversely, when an element is referred to as "directly connected" or "directly coupled" to another element, there are no intermediate elements between that element and the other element. It will be understood that these terms are intended to encompass different orientations of elements other than those depicted in the figures.

[0008] In this document, related terms such as “below,” “above,” “over,” “under,” “horizontal,” or “vertical” may be used to describe the relationship between one element, layer, or region and another element, layer, or region illustrated in the figure. It will be understood that these terms are intended to encompass different orientations of the device other than those depicted in the figure.

[0009] Figure 1A This is a diagram of an example LED array 100a used in LED headlight systems, such as ADB headlight systems. Figure 1A In the example illustrated, LED array 100a includes six LEDs 120a (in... Figure 1A Only one was marked in the text. Figure 1A Six LEDs are shown, but those skilled in the art will understand that, consistent with the embodiments described herein, LED arrays can have varying numbers of LEDs in varying numbers of rows and columns. Each of the LEDs 120a has a light-emitting region 130a from which most of the light from the LED 120a is emitted. Adjacent LEDs 120a may be spaced apart by a distance w1 in the horizontal direction and by a distance w2 in the vertical direction. For conventional LEDs, as mentioned above, the distances w1 and w2 are relatively large, such as approximately greater than or equal to 500 µm. For such a system, as mentioned above, pre-optics or primary optics may be required.

[0010] Direct imaging systems that do not require pre-optics or primary optics are becoming increasingly mainstream due to their low manufacturing cost. Direct imaging systems can be achieved by reducing the spacing between adjacent LEDs in an LED array.

[0011] Figure 1B This is a diagram of another example LED array 100b used in LED headlight systems, such as ADB headlight systems. Similar to... Figure 1A The LED arrays 100a and 100b shown in the figure include six LEDs 120ba (in Figure 1A Only one was marked in the text. Figure 1B Six LEDs are shown, but those skilled in the art will understand that, consistent with the embodiments described herein, LED arrays can have different numbers of LEDs in different numbers of rows and columns. Each of the LEDs 120b has a light-emitting region 130b from which most of the light from the LED 120b is emitted. Adjacent LEDs 120b have a fine spacing, or in other words, they can be spaced apart by a distance w3 in the horizontal direction and by a distance w4 in the vertical direction. For direct imaging systems, such as Figure 1BAs illustrated in the diagram, distances w3 and w4 can be significantly smaller than distances w1 and w2. For example, distances w3 and w4 can be approximately 50 µm or less.

[0012] Figure 2 This is a top view of an example finely spaced LED array 200 used in an ADB headlight system. Figure 2 In the illustrated example, for simplicity, a portion of the LED array 200 is shown. Figure 2 The section shown includes four rows of LEDs, each row consisting of seven complete LEDs (half of the two LEDs at the edge of each row are also included). Figure 2 (As shown in the figure). Consistent with the embodiments described herein, the number of LEDs in each row may not be limited to seven or even nine, or may even include fewer LEDs per row.

[0013] Figure 2 This example illustrates the electrical wiring required for a finely spaced LED array. For such LED arrays, especially those formed on ceramic substrates or copper-insulated metal substrates (IMS) PCBs, unique heat dissipation requirements necessitate that the electrical wiring be limited to a single layer. For example... Figure 2 As shown, conductive connectors 240a and 240b can be used to electrically couple LEDs in the array together in series. For example, LED 220a can be electrically coupled in series to LED 220b via conductive connector 240a, and electrically coupled in series to LED 220c via conductive connector 240b. The conductive connectors can be any type of single-layer conductive connector known in the art, such as metal traces.

[0014] Figure 3 This is an example of a finely spaced LED array (such as...) Figure 2 The circuit diagram 300 shows a finely spaced LED array 200. Figure 3 The illustrated example shows a finely spaced LED array 300 comprising four rows of LEDs 320 (labeled row 1, row 2, row 3, and row 4), with each row containing four LEDs 320. Figure 2 Similar to the finely spaced LED array 200, array 300 may include more or fewer LEDs per row, consistent with the embodiments described herein. To simplify the circuit diagram, Figure 3 Only four LEDs are shown in each row.

[0015] Figure 3The diagram illustrates two groups 360 and 370 of LEDs 320. Each group comprises two rows of LEDs 320, and the LEDs 320 in each group are electrically coupled together in series. For example, LED 320b in row 2 is electrically coupled in series with LED 320a in row 1 via conductive connector 340a, and is electrically coupled in series with LED 320c in row 1 via conductive connector 340b. Each LED 320 in rows 1 and 2 can be electrically coupled in the same manner. Similarly, each LED 320 in rows 3 and 4 can be electrically coupled in the same manner. The conductive connectors can be any type of single-layer conductive connector known in the art, such as metal traces. The LEDs 320 in each of groups 360 and 370 can be energized and de-energized, for example, by supplying power to each group via cathode or anode lines (e.g., cathode or anode lines 345a, 345b, respectively). To enable addressability of individual LEDs, LED320b can be turned off by shorting conductive connectors 345c and 345d with a medium (e.g., an external switch).

[0016] Such as Figure 1B , Figure 2 and Figure 3 The direct imaging system shown offers many advantages over conventional LED headlights. For example, the headlight system itself can be simplified by removing the primary / collimating optics. Furthermore, the direct imaging system is relatively inexpensive to manufacture compared to conventional headlight systems with shorter time-to-market. Direct imaging systems can also be more compact and are more robust to assembly tolerances. However, given the limitations of single-layer wiring, it is practically impossible to add additional LED rows to an LED array with individual addressability, resulting in practical limitations on the size of such arrays. The embodiments described herein provide a solution for finely spaced LED arrays that can be expanded to include additional LED rows, and in some embodiments, can be used for direct imaging in ADB headlight systems (i.e., omitting the need for primary optics) to increase the vertical field of view of the LED array.

[0017] Figure 4 This is a top view of another example of a finely spaced LED array 400 used in an ADB headlight system. Figure 4 In the illustrated example, each row shows five LEDs 420. Consistent with the embodiments described herein, the number of LEDs per row may not be limited to five, or may even include fewer LEDs per row.

[0018] Figure 4 The array 400 shown includes a fifth row of LEDs. Conductive connectors 440a and 440b can be used to electrically couple some of the LEDs in the array together in series. For example, with... Figure 2The LED 220 in the row can be electrically coupled in a similar manner. LEDs 420 in rows 1 and 2 can be electrically coupled together in series, and LEDs 420 in rows 3 and 4 can be electrically coupled together in series. For example, LED 420a in row 1 can be electrically coupled in series to LED 420b in row 2 via conductive connector 440a, and electrically coupled in series to LED 420c in row 1 via conductive connector 440b.

[0019] Due to the limitations of single-layer wiring in finely spaced LED arrays, LED 420 in row 5 is electrically coupled in parallel with LED 420 in row 4. Figure 4 In the illustrated example, for instance, LED 420d in row 5 is electrically coupled in series with LED 420e in row 4 via conductive connectors 440c and 440d. The conductive connectors can be any type of single-layer conductive connector known in the art, such as metal traces.

[0020] Figure 5 This is an example of a finely spaced LED array (such as...) Figure 4 Circuit diagram of a finely spaced LED array (400). Figure 5 The illustrated example shows a finely spaced LED array 500 comprising six rows of LEDs 520, with each row containing four LEDs 520. Figure 4 Similar to the finely spaced LED array 400, array 500 may include more or fewer LEDs per row, consistent with the embodiments described herein. To simplify the circuit diagram, Figure 5 Only four LEDs are shown in each row.

[0021] Figure 5 The diagram shows three groups 560, 570, and 580 of LEDs 520. Groups 560 and 570 each include two rows of LEDs 520, and the LEDs 520 in each of these groups are electrically coupled together in series. For example, LED 520b in row 2 is electrically coupled in series with LED 520a in row 1 via conductive connector 540a, and is electrically coupled in series with LED 520c in row 1 via conductive connector 540b. Each LED 520 in rows 1 and 2 can be electrically coupled in the same manner. Similarly, each LED 520 in rows 3 and 4 can be electrically coupled in the same manner.

[0022] Similar to Figure 4 In array 400, LED 520 in row 5 can be electrically coupled in parallel with LEDs in row 4. For example, LED 520f in row 5 can be electrically coupled in parallel with LED 520e in row 4 via conductive connectors 540c and 540d. Figure 5As illustrated, additional rows can be added below row 5 to further increase the vertical field of view of the LED array. For example, row 6 in... Figure 5 The array is shown as optional and includes a row of LEDs 520. By way of example, LED 520g is shown electrically coupled in parallel to LED 520f in row 5 via conductive connectors 540c and 540d. This can be repeated in an additional row below row 6, and / or an additional row can be added in parallel with row 1 above array 500. In this way, LEDs 520 in group 580 are electrically coupled in parallel to LEDs 520 in group 570. The conductive connectors can be any type of single-layer conductive connector known in the art, such as metal traces.

[0023] One drawback of this arrangement is that the parallel-coupled LEDs cannot be individually addressed. They are turned on and off using LEDs in a row of parallel-coupled LEDs. (See above regarding...) Figure 3 As explained, the LED in group 560 can be energized and de-energized via the supplied current through the anode wire 545a and the cathode wire 545b. Similarly, the LEDs in groups 570 and 580 can be energized and de-energized in the same manner.

[0024] Parallel electrical coupling of LED 520 in group 580 and LED 520 in group 570 can cause current surge effects due to uneven current flow to the LEDs caused by the forward voltage of the LEDs. To address this issue, the LEDs used in this array may need to be pre-balanced in smaller steps to ensure minimal variation in forward voltage between LEDs in the array.

[0025] Figure 6 This is a diagram of an example vehicle headlight system 600. Figure 6 The example vehicle headlight system 600 illustrated includes an application platform 602, two LED lighting systems 606 and 608, and secondary optics 610 and 612. When an LED array is used in LED lighting systems 606 and 608 (such as...), Figure 4 and Figure 5 As illustrated, primary optical components may not be necessary in system 600.

[0026] LED lighting system 608 can emit a beam of light 614 ( Figure 6 (As indicated by arrows 614a and 614b). The LED lighting system 606 can emit a beam 616 ( Figure 6 (As indicated by the middle arrows 616a and 616b). In Figure 6In the illustrated embodiment, secondary optics 610 are adjacent to LED lighting system 608, and light emitted from LED lighting system 608 passes through secondary optics 610. Similarly, secondary optics 612 are adjacent to LED lighting system 606, and light emitted from LED lighting system 606 passes through secondary optics 612. In an alternative embodiment, secondary optics 610 / 612 are not provided in the vehicle headlight system.

[0027] The location including secondary optics 610 / 612 may include one or more light guides. The one or more light guides may be edge-illuminated or may have internal openings defining internal edges of the light guides. LED lighting systems 608 and 606 may be inserted into the internal openings of one or more light guides, such that they inject light into the inner edge (internal opening light guide) or outer edge (edge-illuminated light guide) of one or more light guides. In embodiments, the one or more light guides may shape the light emitted by LED lighting systems 608 and 606 in a desired manner, such as, for example, utilizing gradients, slanted distributions, narrow distributions, wide distributions, or angular distributions.

[0028] Application platform 602 can provide power and / or data to LED lighting systems 806 and / or 608 via line 604. One or more sensors (which may be sensors in the vehicle headlight system 800 or other additional sensors) may be inside or outside the housing of application platform 602. Alternatively or additionally, each LED lighting system 608 and 606 may include its own sensor module, connectivity and control module, power supply module, and / or LED array.

[0029] In an embodiment, the vehicle headlight system 600 may represent a car with a maneuverable beam of light, wherein LEDs can be selectively activated to provide maneuverable light. For example, LEDs or an array of emitters may be used to define or project shapes or patterns, or to illuminate only selected portions of a road. In an example embodiment, infrared camera or detector pixels within LED lighting systems 606 and 608 may be sensors that identify portions of a scene (e.g., a road or pedestrian crossing) that require illumination.

[0030] Figure 7 This is flowchart 700, which is an example method for manufacturing a finely spaced LED array. Figure 7 In the illustrated example, the method includes selecting boxed LEDs (710) with a forward voltage variation of no more than 0.08 volts or less. The LEDs can be arranged in at least 5 rows, with the spacing between adjacent LEDs less than 100 micrometers (720). The LEDs in the first 4 rows can be electrically coupled together in series (730). The LEDs in the fifth row can be electrically coupled in parallel with the LEDs in the fourth row (740).

[0031] In some embodiments, the array may include more than five rows of LEDs. For example, at least one additional row of selected LEDs may be added below the fifth row. The LEDs in at least one additional row may be electrically coupled in parallel with the LEDs in the fifth row. In another example, at least one additional row of selected LEDs may be added above the first row of LEDs. The LEDs in at least one additional row may be electrically coupled in parallel with the LEDs in the first row. The LEDs in the array may be arranged such that the LEDs in the first and second rows may be powered by an independent power supply, and the LEDs in the third, fourth, and fifth rows may be powered by another independent power supply.

[0032] In some embodiments, to save on the cost of compartmentalized LEDs, only LEDs in parallel electrical coupling can be compartmentalized, ensuring that their forward voltage variation does not exceed 0.08 volts. Other LEDs in the array can be selected with a wider acceptable range of forward voltage deviation, as excessive current may not be a problem for these LEDs.

[0033] As will be apparent to those skilled in the art, based on the description herein, embodiments of the present invention can be designed in software using a hardware description language (HDL) (such as, for example, Verilog or VHDL). HDL designs can model the behavior of electronic systems, where the designs can be synthesized and ultimately manufactured into hardware devices. Furthermore, HDL designs can be stored in computer products and loaded into computer systems prior to hardware manufacturing.

[0034] Having described the embodiments in detail, those skilled in the art will understand that modifications can be made to the embodiments described herein without departing from the spirit of the inventive concept. Therefore, it is not intended to limit the scope of the invention to the specific embodiments illustrated and described.

Claims

1. A light-emitting diode (LED) lighting system, comprising: An array of LED rows and columns, wherein the spacing between adjacent LEDs in the array is less than 100 micrometers, the array comprising at least 5 rows of LEDs; Multiple first conductive connectors electrically couple the LEDs in the first four of the five rows in series. and Multiple second conductive connectors electrically couple the LEDs in the fifth row of the 5 rows to the LEDs in the fourth row of the 5 rows in parallel.

2. The lighting system of claim 1, wherein the variation of the forward voltage of each LED in the array with each other does not exceed 0.08 volts.

3. The lighting system of claim 1 further includes at least one additional row of LEDs below the fifth row, wherein the LEDs in the at least one additional row of LEDs are electrically coupled in parallel with the LEDs in the fourth and fifth rows.

4. The lighting system of claim 1 further includes at least one additional row of LEDs above the first row of the five rows of LEDs, wherein the LEDs in the at least one additional row of LEDs are electrically coupled in parallel with the LEDs in the first row.

5. The lighting system of claim 1, wherein the LEDs in the array are arranged such that the LEDs in the first and second rows of the five rows of LEDs are powered by an independent power supply, and the LEDs in the third, fourth and fifth rows of the five rows of LEDs are powered by another independent power supply.

6. An automotive lighting system, comprising: Two LED lighting systems, each system comprising: An array of LED rows and columns, wherein the spacing between adjacent LEDs in the array is less than 100 micrometers, the array comprising at least 5 rows of LEDs. Multiple first conductive connectors, which are electrically coupled in series to the LEDs in the first four rows of five rows, and Multiple second conductive connectors electrically couple the LEDs in the fifth row of the 5 rows to the LEDs in the fourth row of the 5 rows in parallel.

7. The system of claim 6, wherein the automotive lighting system is an adaptive high beam system.

8. The system of claim 6 further includes a secondary optics for each of the LED lighting systems, wherein the two LED lighting systems do not include a primary optics.

9. The system of claim 6, wherein the variation of the forward voltage of each LED in each of the array with each other does not exceed 0.08 volts.

10. The system of claim 6, wherein each of the LED lighting systems further comprises at least one additional row of LEDs below the fifth row, wherein the LEDs in the at least one additional row of LEDs are electrically coupled in parallel with the LEDs in the fourth and fifth rows.

11. The system of claim 6, wherein each of the LED lighting systems further comprises at least one additional row of LEDs above the first row of the five rows of LEDs, the LEDs in the at least one additional row of LEDs being electrically coupled in parallel with the LEDs in the first row.

12. The system of claim 6 further includes a controller configured to power the LEDs in the first and second rows of the five rows of LEDs from an independent power source, wherein the LEDs in the third, fourth, and fifth rows of the five rows of LEDs shall be powered by another independent power source.

13. A method for manufacturing an LED lighting system, the method comprising: Select multiple LEDs in separate boxes such that the selected LEDs have a positive voltage that varies by no more than 0.08 volts among the selected LEDs; Arrange the selected LEDs in at least five rows, with the spacing between adjacent LEDs being less than 100 micrometers; Connect the LEDs in the first 4 of the 5 rows in series for electrical coupling; and Connect the LED in the fifth row of the five rows to the LED in the fourth row of the five rows in parallel.

14. The method of claim 13, further comprising: Add at least one additional row of selected LEDs below the fifth row; and At least one LED in an extra row is electrically coupled in parallel with LEDs in the fourth and fifth rows.

15. The method of claim 13, further comprising: Add at least one additional row of selected LEDs above the first row of the 5 rows of LEDs; and At least one LED in an additional row is electrically coupled in parallel to the LED in the first row.

16. The method of claim 13, wherein the LEDs in the array are arranged such that the LEDs in the first and second rows of the five rows of LEDs are powered by an independent power supply, and the LEDs in the third, fourth and fifth rows of the five rows of LEDs are powered by another independent power supply.

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