Wavelength converter and LED die for correcting edge color shift and method of manufacturing the same

Abstract

A wavelength converter for shaping the surface brightness of an LED die is described. The wavelength converter, when energized, produces a peak brightness in a region of the LED die. The wavelength converter includes a body of wavelength conversion material having a width, a length, and a height. A cross-section of the body in the length direction has a shape such that, when the wavelength converter is mounted over the LED die, the height of the body is greater near the region of the LED die where the peak brightness is produced.

Description

[0001] Cross-references to related applications This application claims the benefit of U.S. Nonprovisional Application No. 18 / 434,517, filed February 6, 2024, the contents of which are incorporated herein by reference. Background Technology

[0002] Light-emitting diodes (LEDs) are increasingly used in lighting applications, such as automotive lighting systems or general lighting applications, to replace more conventionally used filament lamps. In some applications, shaped surface brightness LEDs can be used to control the brightness distribution of the light emitted by the LED across its surface area. The brightness distribution can be represented graphically as a brightness map, where a series of peaks and valleys define areas of brightness above or below the average value on the LED surface area; the highest point is called the "peak brightness." Summary of the Invention

[0003] A wavelength converter for shaping the surface brightness of an LED die is described. The wavelength converter generates peak brightness in a region of the LED die when powered on. The wavelength converter includes a body of wavelength conversion material having a width, length, and height. The cross-section of the body in the length direction has a shape such that when the wavelength converter is mounted above the LED die, the height of the body is relatively large in the vicinity of the region of the LED die where the peak brightness is generated. Attached Figure Description

[0004] A more detailed understanding can be obtained through the following description, presented with reference to the accompanying drawings, which are given by way of example: Figure 1 The diagram illustrates an exemplary conventional wavelength converter for LEDs, shown as (a) a side view and (b) a perspective view; Figure 2 It is a uniform core (e.g.) Figure 1 Figures showing (a) brightness diagram, (b) v' diagram and (c) v' cross-sectional diagram of the uniform core shown; Figure 3 This is a diagram illustrating an exemplary LED exhibiting an edge color shift effect occurring in one or more overhang regions; Figure 4 It is an edge-offset brightness die (e.g.) Figure 3 The diagrams shown are (a) a brightness diagram, (b) a v' diagram, and (c) a v' cross-sectional view of the edge-off brightness die. Figure 5 This is a diagram of an LED with a low transparency wavelength converter; Figure 6 This is a diagram of an LED including a cap-shaped wavelength converter, which is surrounded by an optical side coating on all sides; Figure 7 This is a diagram of an exemplary shaped wavelength converter optimized to correct source-on-source color (CoS) variations in the brightness of shaped surface LEDs; Figure 8 and Figure 9 These are diagrams illustrating different shapes of exemplary shaped wavelength converters consistent with the embodiments described herein; Figure 10 It is an asymmetric truncated pyramidal wavelength converter (e.g.) Figure 7 (a) brightness plot, (b) v' plot and (c) v' cross-sectional plot of the wavelength conversion layer; Figure 11 This is an example of a simulated cross-sectional view of v'; Figure 12 This is a flowchart of an exemplary method for manufacturing a shaped wavelength converter consistent with the embodiments described herein; Figure 13 This is a flowchart of an exemplary method for manufacturing a shaped wavelength converter for shaping surface brightness LED dies; Figure 14A This demonstrates how to cut palm blanks into wedge shapes using a single pass (e.g., as shown in the image). Figure 9 A graph showing the parameters of the blade (as shown). Figure 14B This demonstrates how to cut palm blanks into shapes using a single pass with each blade, such as... Figure 7 or Figure 8 A diagram showing the parameters of the two blades of the shape shown; Figure 14C This illustrates a method for cutting palm blanks into shapes using multiple passes (e.g.) Figure 9 A diagram showing the parameters of the smaller blade (of the wedge shape); Figure 15 This is a diagram illustrating a wavelength converter formed using additive manufacturing methods at various stages of the manufacturing process; and Figure 16 This is a flowchart of an exemplary method for assembling LEDs. Detailed Implementation

[0005] Examples of different lighting 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 further implementations. Therefore, it should be understood that the examples shown in the drawings are for illustrative purposes only and are not intended to limit this disclosure in any way. The same reference numerals denote the same elements throughout the text.

[0006] It should 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 all combinations of one or more of the associated listed items.

[0007] It should be understood that when an element (e.g., a layer, region, or substrate) is referred to as being "on" or "extending" to "another element," the element may be directly on or directly extended to the other element, or intermediate elements may be present. Conversely, when an element is referred to as being "directly on" or "directly extended to" another element, intermediate elements may not be present. It should also be understood that when an element is referred to as being "connected" or "coupled" to another element, the element may be directly connected or coupled to the other element, and / or connected or coupled to the other element through one or more intermediate elements. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intermediate elements between the element and the other element. It should be understood that, except for any orientation shown in the accompanying drawings, these terms are intended to cover different orientations of elements.

[0008] This document may use relative terms (e.g., "below," "above," "upper," "lower," "horizontal," or "vertical") to describe the relationship between one element, layer, or region shown in the accompanying drawings and another element, layer, or region. It should be understood that these terms are intended to cover different orientations of the apparatus, in addition to those shown in the accompanying drawings.

[0009] After a detailed description of the embodiments, 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, the scope of the invention is not intended to be limited to the specific embodiments shown and described.

[0010] Analysis of some automotive system optics indicates that shaped surface brightness LEDs with peak brightness located at the center of the LED provide optimal system performance for systems with total internal reflection (TIR) ​​lenses. Conversely, LED surface brightness with a gradient from one side to the other can provide optimal system performance for systems with reflectors. This contrasts with uniform dies that have a more uniform surface brightness distribution. System optical performance can be evaluated using the system optical quality factor (FOM), which assesses the intensity and quality of light distribution on the road. In the embodiments described herein, LED dies with a center peak brightness distribution can be referred to as center peak brightness (CPL) dies, and LED dies with edge-offset brightness can be referred to as edge-offset brightness (ESL) dies. Generally, a die with a shaped brightness profile can be defined as a die whose average brightness deviates from the average brightness over at least 10% (10%) of the total luminous area by more than 20% (20%) of the average brightness over the entire luminous area. The area with the largest brightness deviation can be referred to as the peak brightness.

[0011] While shaped surface brightness LEDs may be advantageous for certain applications, as mentioned above, such LEDs can also cause potentially undesirable color variations in the light emitted from the LED. These variations can be assessed by analyzing, for example, system optical metrics such as luminous efficacy (which can be determined by Vf and LED luminous flux), source-on-source color (CoS) variation and / or role variation, and thermal resistance. Strong CoS variations can be particularly significant as they can lead to drastic and unpleasant color changes in light projected onto a road.

[0012] Figure 1 The diagram illustrates an exemplary conventional wavelength converter 100 for a uniform LED die, shown as (a) a side view and (b) a perspective view. Figure 1 In the example shown, the wavelength converter 100 may have a top surface 104 and a bottom surface opposite the top surface (in... Figure 1 (Not visible in the center) and at least one side 102. As can be seen from the side view in (a), the wavelength converter has a uniform surface profile defined by a uniform height across the entire side 102. Figure 1 In the example shown, the wavelength converter 100 has a uniform height of about 73 µm and a width of about 1060 µm, but these dimensions can vary, for example, depending on design constraints.

[0013] exist Figure 1In the example shown, wavelength converter 100 may be a ceramic phosphor wafer. However, those skilled in the art will understand that other types of wavelength converters may be used, such as phosphors in silicone or glass. Unless otherwise stated, as used throughout, the term wavelength converter may include one or more layers of any type of wavelength conversion material, including but not limited to ceramic phosphor wafers, phosphors in silicone, or phosphors in glass.

[0014] Figure 2 These are diagrams of (a) brightness, (b) v' plot, and (c) v' cross-sectional plot of a uniform die. The uniform die can be, for example, a standard 1 mm² uniform die. Figure 1 In the example shown, for a uniform die, the brightness pattern is roughly centered relative to the surface area of ​​the LED (i.e., the peak intensity is roughly centered in the die), and the variation of the light intensity v' is relatively small.

[0015] Figure 3 This is a diagram of an exemplary ESL LED 300. Figure 3 In the example shown, LED 300 includes LED die 308, which may include an epitaxial layer 320 on a substrate 308 (e.g., a sapphire substrate). A wavelength converter 312 is disposed above LED die 302 and may be fixed to LED die 302, for example, by adhesive 310. The top surface of wavelength converter 312 may be referred to as light-emitting region (LEA) 326, in which light is emitted from LED 300. Figure 3 In the example shown, LEA 326 occupies the entire top surface of wavelength converter 312; however, those skilled in the art will understand that in practice, LEA may occupy an area smaller than the entire top surface. Conductive contacts 322 and 324 may be disposed on or near the bottom surface of LED die 308, and these contacts may be used to supply current from an external power source (not shown) to drive LED 300, thereby energizing and de-energizing it. Conductive contact 314 may be shaped and positioned to facilitate current injection into specific portions of the die (e.g., ...). Figure 3 (As shown).

[0016] In some embodiments, highly reflective materials ( Figure 3 (not shown) (e.g., an optical side coating) may be placed around one or more sides of the LED die 302 and wavelength converter 312 to prevent the LED 300 from emitting light outside the LEA 326. Figure 3 In the example shown, the wavelength converter 312 extends beyond the LED die 302 in the overhang region 304. The wavelength converter 312 may extend beyond the LED die 302 on all sides.

[0017] Figure 3The image illustrates the edge color shift effect occurring in one or more overhang regions 304. One or more overhang regions 304 may be necessary to avoid the presence of blue light rays that do not pass through the wafer. In practice, the wavelength converter 312 can be tens of micrometers larger than the LED die 302, taking into account variations due to manufacturing tolerances and wafer misalignment.

[0018] like Figure 3 As can be seen, the LED die 320 emits axial rays 318 and oblique rays 316. The axial rays can pass unconverted through the wavelength converter 312, and the oblique rays can be absorbed by the phosphor particles 306 in the wavelength converter 312 and re-emitted as light of a different color. For example, in the peak brightness region 314, due to geometry, the LED die 320 emits significantly more oblique rays, which travel a longer distance through the wavelength converter 312 than the axial rays 318. This can lead to edge color shift, where the light emitted through the wavelength converter 312 may appear more yellow to the observer in areas far from the peak brightness region 314 than in the peak brightness region 314. Therefore, such as Figure 3 The LED 300 shown may have the significant drawback of high CoS variation.

[0019] This edge color shift phenomenon tends to occur in all shaped surface brightness LEDs based on non-uniform current distributions, which may also suffer from the drawback of strong CoS variation. Similar to... Figure 3 The LED 300 shown, for this type of shaped surface brightness LED based on non-uniform current distribution, may appear yellower due to the light emitted through the portion far from the peak brightness region compared to the light emitted through the peak brightness region.

[0020] Figure 4 It is an edge-offset brightness die (e.g.) Figure 3 The figures shown are (a) a brightness diagram, (b) a v' diagram, and (c) a v' cross-sectional view of the edge-off brightness die. Figure 2 Compared to the provided figures, edge-offset brightness dies exhibit at least a 50-point v' variation between the peak brightness region and the overhanging region. It should be noted that the color variation on the surface will directly depend on brightness uniformity and the associated current uniformity. The higher the current uniformity across the LED's LEA, the greater the CoS variation will be. Unlike uniform dies, the whitest blue region of the ESL die matches the peak brightness region. This is critical for system optical performance, as this peak brightness region will contribute the most to the cutoff color in low-beam automotive optics or the peak intensity in high-beam automotive optics.

[0021] Traditional shaped brightness LEDs are designed to facilitate current injection into specific portions of the LED die. However, this approach results in strong CoS variations, such as... Figure 3 and Figure 4 As shown and as mentioned above, because the oblique rays emitted near the peak brightness region will be converted more than the rays emitted at the center of the die.

[0022] Figure 5 This is a cross-sectional view of an LED 500 with a low-transparency wavelength converter 512. (As shown) Figure 5 As shown, a traditional approach to addressing the strong CoS variation in conventionally shaped brightness LEDs can be achieved by using a thick, low-transparency wavelength converter 512, which is achieved by providing a high-density scattering aperture 540. This high-density scattering aperture 540 can scatter light in all directions, resulting in better color mixing of the light emitted through the LEA 526. All other parts of the LED 500 can be connected with… Figure 3 The LED 300 shown is the same as or similar to the one described. For example, the wavelength converter 512 may also include phosphor particles 506, and the wavelength converter may be disposed above the LED die 502, which may be connected to... Figure 3 The LED die 302 is the same as or similar to that of the LED 500. While the LED 500 can slightly improve edge color shift by providing better color mixing, it may also reduce luminous flux and surface brightness due to its optical side coating (not shown but mentioned above). Figure 3 The interactions described may be higher.

[0023] Figure 6 This is a cross-sectional view of LED 600, which includes a cap-shaped wavelength converter 612 surrounded on all sides by an optical side coating 650. Figure 6 In the example shown, the wavelength converter 612 has a visor region 652 adjacent to the top surface of the LED die 620. Figure 6 Only the substrate of the LED die 620 is marked. Although the substrate is... Figure 6 The substrate is labeled as sapphire, but as those skilled in the art will understand, any suitable type of substrate can be used for LED die 620. The crown 654 of the wavelength converter 612 extends upward from the brim, giving the wavelength converter 612 an inverted cap shape.

[0024] exist Figure 6 In the example shown, the brim region 652 of the wavelength converter 612 is completely covered on all sides by a diffuse optical side coating 650. This reduces color shift on the brim region 652 of the wavelength converter 612 because almost no light will be emitted through the overhang region 628 (in Figure 6(Only one of the overhanging areas is marked in the image). However, this design will also reduce luminous flux and requires a thick wavelength converter 612 to ensure that no light is emitted above the brim area 652. For example, in some cases, the wavelength converter can be as thick as about 200 µm or more.

[0025] The embodiments described herein can provide a shaped surface brightness LED that can provide minimal CoS variation without compromising system FOM performance (e.g., quality based on road light distribution and luminous flux). This embodiment reduces the optical path of light through the LED's wavelength converter toward the outer edge of the wavelength converter. This can be achieved, for example, by cutting one or more corners of the wavelength converter on the light-emitting side.

[0026] Figure 7 This is a diagram of an exemplary shaping wavelength converter 700 optimized to correct for CoS variations in the brightness of a shaped surface LED. The shaping wavelength converter 700 is shown as a cross-sectional view (a) and a perspective view (b) taken along the x-line. Figure 7 In the example shown, the wavelength converter 712 is used for a 1 mm² LED die (not shown) and has four sides 764, 766, 768, and 770, and a top surface 762. One or more of the edges 772, 774, 776, and 778 between the sides 764, 766, 768, and 770 can be curved or angled. Figure 7 In the example shown, all four edges 772, 774, 776, and 778 are curved. The approximate cross-sectional shape of the wavelength converter can be seen in cross-sectional view (a). Each of edges 772, 774, 776, and 778 is curved, and the curved shape has a corresponding angle θ and a bending length L. The shaped wavelength converter 700 can be designed for use with standard 1 mm² LED dies. How to choose the value of θ to apply the teachings of this paper to LED dies of other sizes will become apparent from the methods described below.

[0027] To correct for the strong CoS variation that a shaped surface brightness LED would otherwise exhibit, at least one edge 772, 774, 776, and / or 778 can be located on the light-emitting side (e.g., on one side of the LED die where the LEA is located) – in Figure 7 For clarity, it is marked as 780 (curved). Figure 7 In the example shown, the value of θ is larger on the die side opposite to the peak brightness side.

[0028] For wavelength converters (e.g.) Figure 7The wavelength converter 712 shown has a height H that decreases from the center toward the outer edge. In other words, the wavelength converter 712 has an asymmetric truncated pyramid shape. This smooth height reduction can provide lower conversion efficiency, thereby reducing the yellow conversion of oblique light, which, for example, compensates for the higher conversion caused by the dominance of oblique light in the overhang region. The angle shape is not necessarily linear (beveled), but can also be curved, for example, having the steepest slope on the die side opposite the peak brightness. Such angle shapes may be collectively referred to herein as curved chamfers. In some embodiments, the ridge may be curved only on the die side opposite the peak brightness or otherwise angled. In other embodiments, such as Figure 7 As shown, all four edges can be curved or otherwise tilted, but the edges on the side opposite to the peak brightness can have a steeper slope (θ) than the edges on the peak brightness side of the LED die.

[0029] Figure 8 and Figure 9 These are figures illustrating different cross-sectional shapes of exemplary wavelength converters according to embodiments described herein. The shaped wavelength converter 812 is shown as a cross-sectional view (a) and a perspective view (b) taken along the yy line. Figure 8 In the example shown, the wavelength converter 812 has two sides 884 and 886 and a top surface 882. Each of the sides 884 and 886 is curved and... Figure 7 Similarly, the bending angle θ is steeper on the side of the lower LED die opposite to the peak brightness. Figure 8 The shape of the wavelength converter in the image can be described as having a ramp shape. The shaped wavelength converter 912 is shown as a cross-sectional view (a) and a perspective view (b) taken along line z. Figure 9 In the example shown, the wavelength converter 912 has a single sloping top surface 892 (or in other words, the wavelength converter 912 is wedge-shaped), and the value of the bending angle θ is selected to allow the height H of the wavelength converter 912 to be lower on the side of the LED die below, opposite to the peak brightness.

[0030] for Figure 7 and / or Figure 8 In the embodiment shown, the length L (only when...) Figure 7 The text is incomplete and appears to be a fragment of a longer document. A more coherent translation would require the full context. Figure 8 The wavelength converter height L extends from a minimum of approximately 50 µm to a maximum of approximately 2 / 4 of the LED die length. As detailed above, the wavelength converter height L will be higher on the peak brightness side of the LED die.

[0031] As mentioned above, different wavelength converter shapes are possible. When one or more values ​​of the bending angle θ are large on the die side opposite to the peak brightness, the wavelength converter will have an asymmetrical shape, regardless of how many bending sides or edges it has, where the surface or edge on the die side opposite the peak brightness has a steeper slope. Reference Figure 7 In an embodiment optimized for a standard 1 mm² LED die, the bend chamfer angle on the die side opposite to peak brightness (e.g., the angles of surface 764 and edges 772 and 774) is approximately 12.5°, while the bend chamfer angles of edges 776 and 778 (on the peak brightness side) are approximately 7°. The bend chamfer length L is approximately 300 µm or approximately one-third of the die length.

[0032] Figure 10 It is an asymmetric truncated pyramidal wavelength converter (e.g.) Figure 7 The wavelength converter 712 is shown in the following figures: (a) brightness diagram, (b) v' diagram, and (c) v' cross-sectional diagram. Figure 10 As can be seen from, for example Figure 3 In contrast, the luminance map still shows a rightward shift in peak luminance values. However, the v' section ratio... Figure 3 The flatter shape indicates that the asymmetric truncated pyramidal wavelength converter provides a much lower CoS variation for a standard 1 mm² LED die compared to conventional wavelength converters.

[0033] Figure 11 This is an exemplary simulation of a cross-sectional view of v'. The diagram is generated based on certain characteristics of the underlying LED die (e.g., dimensions) and the wavelength converter (e.g., material). Figure 11 In the example shown, the graph is obtained by targeting a converter (e.g.) Figure 7 The converter shown is generated by taking the average value of v' over a 100 µm band in the y direction and over the entire die length in the x direction for a given LED. As mentioned above, this graph will change if there are any changes in the converter design, such as scattering ability, different materials, different dopants, small die design variations, die designs with more pronounced gradients, etc. Figure 11 The dashed line in the graph represents the average value of v' across the entire surface of the LEA of the selected LED die. Analysis of this graph can provide an optimized value for θ, as described in detail below.

[0034] Figure 12 This is a flowchart of an exemplary method for manufacturing a wavelength converter according to embodiments described herein. Figure 12 In the example shown, as above regarding Figure 11The (1202) shaped brightness profile LED die can be selected for a given application, for example, based on application specifications. For the embodiments described herein, a shaped brightness profile LED die will be selected. The selected shaped brightness profile LED die will have certain parameters that are likely best suited to the specific application, such as the size of the LED die. Parameters of the (1204) wavelength converter (other than its shape) can be selected. For example, one or more materials of the wavelength converter can be selected, such as ceramic phosphors or phosphors in another medium (e.g., silicone or glass). For the purposes of this example method, it is assumed that a standard shaped brightness profile LED die with a size of 1 mm² is selected, and the wavelength converter will be formed from ceramic phosphors.

[0035] A simulated v' cross-sectional plot (1206) can be generated based on the characteristics of the selected die and wavelength converter. The degree of color shift (1208) can be determined from the simulated v' cross-sectional plot. This can be determined by observing the portion of the curve above the dashed line in the plot, which represents the average v' value across the entire LEA surface. For example, from... Figure 11 As shown in the diagram, the curve has two continuous portions above the dashed line, one on the left and one on the right. If the diameter of the continuous portion above the dashed line is greater than (>) approximately 50 µm, this portion can be considered to represent a large degree of color cast. Conversely, if the diameter of the continuous portion above the dashed line is less than (<) approximately 50 µm, this portion can be considered to represent a small degree of color cast. Figure 11 In the example shown, curve portion 1102 has a diameter >50 µm, and is therefore considered to have a high degree of color cast. Curve portion 104 has a diameter <50 µm, and is therefore considered to have a low degree of color cast.

[0036] The tilt angle of at least one surface or edge of the wavelength converter (1210) can be selected, for example, based on the determination in 1208. Rules can be established such that the angle between the tangent of curvature (at the outer starting point) and the horizontal line should be greater than 10° to correct for large color shifts (>50 µm) and less than 10° to correct for small color shifts (<50 µm). The angle between the tangent of curvature (at the outer starting point) and the horizontal line is... Figure 7 The shape is represented by θ, and can be used for other shapes (e.g.) Figure 8 and Figure 9 The shape shown is similarly defined, as will be apparent to those skilled in the art. For Figure 11 In the example shown, and assuming an asymmetric truncated pyramidal wavelength converter, the angle θ of the two edges on the peak brightness side of the LED can be chosen to be 12.5°. The angle θ of the two edges on the non-peak brightness side of the LED can be chosen to be 7.0°.

[0037] Alternatively, rules can be established based on the height of the small patch. For example, a rule could be established that the ratio of the height at the outermost point of a small patch to the maximum height of the small patch should be less than a threshold. Various small patch heights, for example, are... Figure 8 As shown, h1 is the height at the outermost point of the patch, and h is the maximum height of the patch (e.g., at the center of the patch). An example rule could be h1 / h < 0.8.

[0038] The (1212) wavelength converter can then be formed using the selected shape and material. Figures 13 to 16 An example of a method that can be used to manufacture the wavelength converter described herein is shown.

[0039] Figure 13 This is a flowchart illustrating an exemplary method for manufacturing a wavelength converter for shaping surface brightness LED dies. Figure 13 In the example shown, the selected LED die (1302) is determined (see...) Figure 12 (1202) refers to the required wavelength converter size. A selected wavelength converter material (1304) with the dimensions determined in 1302 can be selected (see [reference]). Figure 12 The body (1204) can be shaped (1306) into a defined shape (see...). Figure 12 Optionally, in some embodiments, the body may be heated as described below where applicable.

[0040] by Figure 13 Guided by these methods, a variety of different approaches can be used to fabricate wavelength converters. In an exemplary embodiment, material subtraction methods (such as cutting or laser ablation techniques) can be used to form the wavelength converter. According to these methods, in Figure 13 Obtaining the bulk material for the selected wavelength in 1304 may, for example, involve obtaining one or more densified rectangular ceramic wafers or obtaining a brown blank. The brown blank may be the bulk of ceramic particles. Organic particles may be sintered off, but the bulk may possess high mechanical strength due to partial sintering of oxide powder.

[0041] In some embodiments, cutting can be used to remove material from the preform to produce shaped wafer wavelength converters. In this embodiment, materials specifically designed for manufacturing selected shapes (e.g., Figure 7 , 8 The cutting blade (as shown in Figure 9 and the shape described above) is used to form the shape.

[0042] Figure 14A This demonstrates how to cut palm blanks into wedge shapes using a single pass (e.g., as shown in the image). Figure 9 A graph showing the parameters of the blade (as shown). Figure 14AIn the example shown, a special cutting blade is manufactured according to the size specifications of the wavelength converter, and this blade is used to cut the brown blank into a wedge shape. For example... Figure 14A As can be seen, the blade is a sharp cutting blade whose size can be determined based on selected parameters of the wafer. A second cut can be made in the x and y directions to separate the wafer into wafers.

[0043] Figure 14B This demonstrates how to cut palm blanks into shapes using a single pass with each blade, such as... Figure 7 or Figure 8 A diagram showing the parameters of two blades of the shape shown. In the first pass, a wide cutting blade can be used to cut to a portion or half the height of the body. Then a smaller blade (e.g., Figure 14B The blade (as shown) cuts through the remaining portion of the body's height (e.g., in the x-direction) to form a stepped body. The body can then be cut in the y-direction to produce individual pieces. In an embodiment, multiple steps can be created by starting with a wider blade and using a smaller blade width and different cutting depths to produce the desired number of steps.

[0044] Figure 14C This demonstrates the ability to create shapes using multiple passes (e.g.) Figure 9 A diagram showing the parameters of the smaller blade (in a wedge shape). In the first pass, sharp blades with different widths and tip angles can be used as needed to create the shape. A second pass can be performed using different blades in the x and y directions to separate the wafer into individual wedges.

[0045] Alternatively, various forming wavelength converters can be manufactured by removing material from the blank, for example, using grinding and / or laser ablation processes. In this embodiment, the material of the body can be removed in multiple passes. Using a laser (e.g., a femtosecond laser) allows for greater freedom in creating shapes, such as those referenced above. Figure 7 , 8 The shape described by 9.

[0046] Using about Figure 14A , 14B Following any of the methods described in 14C, one or more palm blanks can be further densified in heating cycles (see [link to 14C]). Figure 13 (1308 in the middle).

[0047] In other exemplary embodiments, the material additive method can be used to form a wavelength converter. According to these methods, in Figure 13Obtaining the bulk material of the selected wavelength in 1304 may include obtaining a green body. The green body may be, for example, a bulk of binder powder or sheet, including, for example, a mixture of ceramic material, at least one phosphor material, and any other required or desired additives, obtained prior to sintering.

[0048] Figure 15 This diagram illustrates the wavelength converter formed using additive manufacturing processes at various stages of the manufacturing process. Figure 15 In the example shown, in (a), multiple green sheets 1510 and 1512 are arranged and laminated in patterns 1530a and 1530b, respectively. Figure 15 The image shows two arrangements that can be further processed to produce wavelength converters with different shapes. Additionally, in... Figure 15 In (a), two different shapes of green sheets 1510 and 1512 are used to form patterns. Sheet 1510 is strip-shaped, while sheet 1512 is plate-shaped. The sheets can be green strips or other smaller sheets of green material. At the top of (a), three rows of green sheets 1512 are stacked, with one row of green sheets 1510 on top. At the bottom of (a), only two rows of green sheets 1512 are stacked, with two rows of green sheets 1510 stacked on top. As described above, each patterned stack in (a) can be laminated to form the green shown in (b). In (b), the green 1540a at the top of the figure includes a laminated stack of green material 1514(a) and a series of green material strips 1516a laminated on top. The green 1540b at the bottom of the figure includes a laminated stack of green material 1514b and a series of double-stacked strips 1516b laminated on top.

[0049] The green blanks 1540a and 1540b shown in (b) can then be isostatically pressed to form deformed green blank wafers 1550a and 1550b, respectively. During this process, one or more top layers (i.e., strip-shaped green blanks) can be shaped to form deformed green blank wafers, which can then be separated to form multiple individual wavelength converters. In some embodiments, for isostatic pressing, a negative mask can be used for an embossing process during pressing. The strip-shaped green blank 1510 may need to be formed from a material with a very low green density to allow the strip-shaped blank 1510 to deform during ISP. In this embodiment, the green blank material will flow under stress due to high pressure, with the shape defined using a mask. By selecting the geometry of the die, the desired shape of the green blank can be manufactured and sintered into the optically densified ceramic bodies 1550a and 1550b shown in (c). As can be seen in (c), two different shapes of top layers 1520a and 1520b are formed by changing the shape of pattern 1530 and / or the green sheet during isostatic pressing and using different molds. Wafers 1550a and 1550b can be diced along the dicing lines (indicated by dashed lines in (d)) or otherwise separated to form individual wavelength converters (e.g., ceramic phosphor wafers) 1552 and 1554 (in... Figure 15 Only 1552a, 1522b, 1524a, and 1524b are marked in the text.

[0050] In some embodiments, the green body can be manufactured using slip casting. Using this technique may also require the use of molds to create top layers of different shapes (e.g., with...). Figure 15 (The top layers 1520a and 1520b in the model are the same or similar). In some embodiments, the green preform can be formed using 3D printing (e.g., inkjet printing). The 3D-printed green preform can be in wafer form, which can be slit after sintering to create individual wavelength converters, or it can be manufactured in the form of a single piece.

[0051] Figure 16 This is a flowchart of an exemplary method for assembling LEDs. Figure 16 In the example shown, a (1602) LED die can be obtained. The LED die can be, for example, a... Figure 12The shaped surface brightness LED die selected in 1202. Selection may include choosing an off-the-shelf LED die, an LED die manufactured by another manufacturer, or an LED die manufactured elsewhere, or may include manufacturing an LED conforming to the desired specifications. A shaped wavelength converter may be obtained (1604). Obtaining may include obtaining a shaped wavelength converter from another manufacturer or obtaining a shaped wavelength converter manufactured elsewhere, or may include manufacturing the wavelength converter by some or all of the methods described above. The LED die and the shaped wavelength converter may be mechanically coupled together (1606) to form an LED. The two components may be mechanically coupled together using any known technique, such as gluing.

[0052] Although features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. Furthermore, the methods described herein can be implemented in computer programs, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over a wired or wireless connection) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor storage devices, magnetic media (e.g., internal hard disks and removable disks), magneto-optical media, and optical media (e.g., read-only optical discs (CD-ROMs) and digital versatile optical discs (DVDs)).

Claims

1. A wavelength converter for shaping the surface brightness of a light-emitting diode (LED) die, the LED die generating peak brightness in a region of the LED die when energized, the wavelength converter comprising: The body of the wavelength conversion material has a width, a length and a height, wherein the cross-section of the body in the length direction has a shape such that when the wavelength converter is mounted above the LED die, the height of the body is larger in the vicinity of the region of the LED die that produces the peak brightness.

2. The wavelength converter according to claim 1, wherein, The cross-sectional shape of the body in the length direction is an asymmetric truncated pyramid.

3. The wavelength converter according to claim 2, wherein, The body has four sides and a top surface, wherein each of the four sides is separated from two adjacent sides by one of four edges, wherein each of the four edges has a curved shape, and wherein, when the wavelength converter is mounted above the LED chip, the two edges of the four edges adjacent to the region of the LED chip that generates the peak brightness have a smaller slope than the two edges of the four edges that are not adjacent to the region of the LED chip that generates the peak brightness.

4. The wavelength converter according to claim 1, wherein, The body has two sides separated from each other by a top surface, and wherein the shape of the cross-section of the body in the length direction is such that, when the wavelength converter is mounted above the LED die, one of the two sides adjacent to the region of the LED die that generates the peak brightness has a smaller slope than the other of the two sides that is not adjacent to the region of the LED die that generates the peak brightness.

5. The wavelength converter according to claim 1, wherein, The body has a wedge shape.

6. The wavelength converter according to claim 1, wherein, The wavelength conversion material is one of ceramic phosphors, phosphors in silicone resins, or phosphors in glass.

7. The wavelength converter according to claim 1, wherein, The main body is a small piece.

8. A shaped surface brightness light-emitting diode (LED), comprising: LED chip, which generates peak brightness in the region of the LED chip when powered on; as well as A wavelength converter, located above the LED die, comprises a body of wavelength conversion material having a width, a length, and a height, wherein the cross-section of the body in the length direction has a shape such that when the wavelength converter is mounted above the LED die, the height of the body is greater in the vicinity of the region of the LED die that produces the peak brightness.

9. The shaped surface brightness LED according to claim 8, wherein, The cross-sectional shape of the body in the length direction is an asymmetric truncated pyramid.

10. The shaped surface brightness LED according to claim 9, wherein, The body has four sides and a top surface, wherein each of the four sides is separated from two adjacent sides by one of four edges, wherein each of the four edges has a curved shape, and wherein, when the wavelength converter is mounted above the LED chip, the two edges of the four edges adjacent to the region of the LED chip that generates the peak brightness have a smaller slope than the two edges of the four edges that are not adjacent to the region of the LED chip that generates the peak brightness.

11. The shaped surface brightness LED according to claim 8, wherein, The body has two sides separated from each other by a top surface, and wherein the shape of the cross-section of the body in the length direction is such that, when the wavelength converter is mounted above the LED die, one of the two sides adjacent to the region of the LED die that generates the peak brightness has a smaller slope than the other of the two sides that is not adjacent to the region of the LED die that generates the peak brightness.

12. The shaped surface brightness LED according to claim 8, wherein, The body has a wedge shape.

13. The shaped surface brightness LED according to claim 8, wherein, The wavelength conversion material is one of ceramic phosphors, phosphors in silicone resins, or phosphors in glass.

14. The shaped surface brightness LED according to claim 8, wherein, The main body is a small piece.

15. A method for manufacturing a light-emitting diode (LED), the method comprising: Select a shaped brightness LED chip, the LED chip being configured to emit light when powered on, such that the light has peak brightness in a region of the LED chip; A wavelength converter is manufactured by forming a body of wavelength conversion material, the body having a width, a length, and a height, wherein the cross-section of the body in the length direction has a shape such that when the wavelength converter is mounted above the LED die, the height of the body is larger in the vicinity of the region of the LED die that produces the peak brightness; as well as The shaped brightness LED chip and the wavelength converter are mechanically coupled together.

16. The method according to claim 15, wherein, Manufacturing the wavelength converter also includes: Select the characteristics of the wavelength converter. Based on the characteristics of the selected wavelength converter and the characteristics of the shaped brightness LED chip, a simulated v' cross-sectional diagram is generated. The degree of color cast was determined from the generated simulated v' cross-sectional diagram, and Based on the determined degree of color shift, a value for the tilt angle of at least one surface or edge of the wavelength converter is selected, such that the degree of color shift is optimized and the height of the body is increased by an optimized amount in the vicinity of the region of the LED die that produces the peak brightness.

17. The method according to claim 15, wherein, The peak brightness is a region within the light-emitting area (LEA) of the LED die, wherein the brightness of the light emitted from this region deviates most from the average brightness value of the LED across the entire LEA.

18. The method according to claim 16, wherein, Manufacturing the wavelength converter also includes: Obtain palm fiber blanks, Based on the selected tilt angle value and the selected shape of the wavelength converter, at least one cutting blade is selected for cutting the brown blank, and The brown blank is cut into the selected shape using at least one selected blade, and at least one pass is made using at least one selected blade.

19. The method of claim 16, wherein, The shape of the wavelength converter is selected from an asymmetric truncated pyramid shape or a ramp shape.

20. The method of claim 16, wherein, Manufacturing the wavelength converter also includes: Laminated green bodies are formed from multiple green sheets. A die is used to press the laminated green preform to shape the topmost green sheet into a wavelength converter wafer, each wavelength converter having the selected shape, and The wafer is diced to form a plurality of separate wavelength converters, each having the selected shape.

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