High precision QCW pitch stack with sintered joints

Abstract

A light-emitting device including a plurality of emitter subassemblies and a lens array, each emitter subassembly including a plate-shaped light emitter having two sides and configured to emit light from an edge, and at least one plate-shaped submount attached to at least one side of the plate-shaped light emitter. Each of the plurality of emitter subassemblies is arranged parallel to one another and sintered together in a manner to form a light-emitting diode stack. A predefined pitch pattern defines the distance between adjacent emitter subassemblies. The lens array is mounted on the light-emitting diode stack and includes a plurality of lenses combined into a single unitary structure. The distance between the lenses corresponds to the distance defined by the predefined pitch pattern, so that each of the plurality of lenses is aligned with a corresponding one of the plate-shaped light emitters.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a PCT application of U.S. Non-Provisional Patent Application No. 18 / 172,342, filed February 22, 2023, and is incorporated herein by reference.

[0002] Technical Field The present invention relates to a high precision laser diode stack and a method for fabricating the same. [Background technology]

[0003] Quasi-continuous wave (QCW) lasers are assembled as stacks of parallel-edge emitting diodes. A QCW laser stack includes subassemblies with submounts and diodes that are bonded together to form a stack. Typically, the subassemblies are joined by reflow soldering to ensure complete electrical and thermal coverage between the subassemblies. However, soldered QCW stacks can pose challenges during assembly, making QCW stack manufacturing time-consuming and costly. For example, stack assemblies can be misaligned or have large tolerances, making it difficult to control quality during assembly. Furthermore, small variations in the spacing between two subassemblies within a stack can result in significant additive differences across the entire stack. Similarly, variations in the thickness of the subassemblies can cumulatively result in large variations in the thickness of the stack. Thickness variations tend to result in multiple stacks that are either all too thick or all too thin, resulting in large overall dimensional variations in the finished stack. Even in the unlikely event that the variations cancel each other out to result in adequate overall stack dimensions, pitch variations between subassemblies necessitate the attachment of individual lenses for each diode in the stack if high beam quality is required. Furthermore, when the stack is formed using soldering, tolerances are typically high enough to necessitate the attachment of individual lenses for each diode in the stack. Attaching individual lenses also adds both time and expense to the QCW stack manufacturing process. Therefore, improvements are needed in the tolerances of QCW stacks, the tolerances of the individual subassemblies of QCW stacks, and the methods for manufacturing QCW stacks.

[0004] Summary of the Invention A light-emitting device comprising a plurality of emitter subassemblies, each of which includes a plate-shaped light emitter having two sides and configured to emit light from an edge disposed between the two sides, and at least one plate-shaped submount attached to at least one side of the plate-shaped light emitter. Each of the plurality of emitter subassemblies is arranged parallel to one another and sintered together in a manner to form a light-emitting diode stack. A predefined pitch pattern defines the distance between adjacent emitter subassemblies. The light-emitting device also comprises a lens array mounted on the light-emitting diode stack, the lens array including a plurality of lenses combined into a single unitary structure. The distance between the lenses corresponds to the distance defined by the predefined pitch pattern, such that each of the plurality of lenses is aligned with a corresponding one of the plate-shaped light emitters.

[0005] The subject matter of the present disclosure will be explained in further detail below based on exemplary figures. All features described and / or illustrated herein can be used alone or in combination in different combinations. The features and advantages of various embodiments will become apparent from reading the following detailed description with reference to the accompanying drawings, which are illustrated below. [Brief explanation of the drawings]

[0006] [Figure 1a] 1 illustrates a radiator subassembly according to an aspect of the present disclosure. [Figure 1b] 1 illustrates a radiator subassembly according to an aspect of the present disclosure. [Figure 1c] 1 illustrates a laser stack according to an aspect of the present disclosure. [Figure 2] 1 illustrates a cooler according to an aspect of the present disclosure. [Figure 3a] 1 illustrates a laser device according to an aspect of the present disclosure. [Figure 3b] 1 illustrates a laser device according to an aspect of the present disclosure. [Figure 3c]1 illustrates a laser device according to an aspect of the present disclosure. [Figure 3d] 1 illustrates a laser device according to an aspect of the present disclosure. [Figure 4a] 1 illustrates a lens array according to an aspect of the present disclosure. [Figure 4b] 1 illustrates a lens array according to an aspect of the present disclosure. [Figure 5a] 1 illustrates an electron microscope scan of a bonded emitter subassembly according to an aspect of the present disclosure. [Figure 5b] 1 illustrates an electron microscope scan of a bonded emitter subassembly according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0007] Embodiments of the present disclosure improve the tolerances of light-emitting stacks, such as QCW "backplane-cooled" laser stacks. Tight pitch patterns create tolerance challenges because they must be matched between the stack and the top metallization of the cooler. This creates challenges in the assembly process of these components. Furthermore, when the laser stack is lensed, each light-emitting subcomponent of the laser stack must be individually lensed, creating challenges due to the very small pitch distance. This process is very labor-intensive compared to processes that can use lens arrays instead. Therefore, embodiments of the present disclosure provide high-precision pitch stacks and enable the use of lens arrays to reduce manufacturing and labor costs while maintaining beam quality comparable to laser stacks with individually lensed lenses.

[0008] In one embodiment, a laser stack is formed by first attaching a laser diode to a submount using a first bonding method. A second submount can be added using a second bonding method. The first and second bonding methods can be the same or different. In some embodiments, an insulator can be attached to the bottom of the submount via a third bonding method. The third bonding method can also bond the submount and laser diode submount assembly into a smaller stack. The laser stack is then stacked on a cooler. The bottom of the laser stack is connected to the cooler using a fourth bonding method.

[0009] If the laser stack does not already have an insulator attached, the insulator can be attached while the uninsulated laser stack is bonded to the cooler by adding an insulator (or insulators) between the laser stack and the cooler. If each of the four bonding methods above were performed via soldering, the solder from the first and second bonding methods could liquefy during the third and fourth bonding methods, potentially resulting in component tolerance stackup. As a result, the total size of the laser stack can vary by as much as 100 micrometers or multiples thereof. In conventionally produced laser stacks, local tolerances can range from 20 micrometers to 200 micrometers. That is, the deviation in the distance between adjacent laser diodes in a laser stack (or, as described in more detail below, the pitch between adjacent laser diodes or their assemblies) can vary from 20 to 200 micrometers between desired distances between adjacent laser diodes in a laser stack. Such high tolerances lead to inefficiencies and quality control issues during manufacturing. Furthermore, lens arrays with precise pre-fabricated pitch between lenses cannot be used because they cannot be attached to the laser stack without tighter controlled tolerances, and individual lenses must be attached. Similarly, pre-fabricated coolers require tight and predictable tolerances for bonding the cooler's metallized contacts to the laser stack.

[0010] In one embodiment, the present disclosure addresses the aforementioned shortcomings of conventional laser stacks by using sintering instead of soldering for at least part of the joining method. Generally, sintering is a joining process that involves the application of pressure (e.g., via compression of the parts being joined) and heat to join solid particles without melting them. The compression ratio used during sintering can be varied without affecting the functionality of sintered laser stacks manufactured to tight dimensional tolerances. The compression ratio is defined by dividing the thickness of the parts after compression by the original thickness of the parts before compression. Therefore, in the present context, the compression ratio represents a value equal to the thickness of the laser stack after compression divided by the original thickness of the laser stack before compression. Sintering ensures that the position of the optical emitter within the laser stack is more accurate than if the laser stack were simply soldered, resulting in reduced manufacturing costs due to the ability to more reliably join the laser stack with pre-fabricated coolers and lens arrays. Furthermore, by selecting a nominal overall height for the laser stack, tolerances of individual components can be compensated for in each sintered layer of the laser stack. Specifically, because laser stacks can collapse to absolute values ​​during sintering, the tolerances of the individual subcomponents of the laser stack (e.g., laser diode, submount, and insulator) can be compensated for by varying the compression of the sintered material provided by the third and fourth bonding methods, thereby ensuring that the completed laser stack has low tolerances that are closer to fixed dimensional values. The result is a laser stack with highly repeatable pitch distances within and across the laser stack. Experimental laser stacks produced according to the present disclosure have achieved local tolerances of 2-20 micrometers, representing a significant improvement over the local tolerances seen in traditional laser stack manufacturing.

[0011] 1a and 1b illustrate emitter subassemblies according to embodiments of the present disclosure. In particular, FIG. 1a illustrates a first emitter subassembly 10 including a laser diode 12 bonded to a submount 14. The laser diode 12 has a substantially planar configuration and emits light along an emitting edge in an emitting direction 13 away from the emitting edge of the laser diode 12. While the laser diode 12 generally emits light in the emitting direction, it will be readily understood that the light emitted from the laser diode 12 is not focused in a precise direction because light rays are scattered and emitted from the emitting edge. Therefore, it should be understood that the emitting direction 13 represents a generalized direction for purposes of describing embodiments of the present disclosure and does not represent the direction of all light emitted from the laser diode 12.

[0012] The submount 14 is a structural member configured to receive the laser diode 12 and provide structural rigidity to a laser stack created using the emitter subassembly, as described in more detail below. In addition to providing structural rigidity and a mounting surface for the laser diode 12, the submount also serves to transfer heat from the laser diode while protecting it from the external environment. Therefore, the submount 14 is preferably formed from a material with very high thermal conductivity to transfer heat away from the laser diode 12. Furthermore, the submount 14 is configured to ensure only low mechanical stress occurs between the laser diode 12 and the submount 14 to which it is bonded, as described below. The submount 14 may include copper tungsten (CuW) or other materials with properties similar to copper tungsten, or other materials as described above. The submount 14 also includes an aperture through which the mounted laser diode 12 can emit light.

[0013] The laser diode 12 may be bonded to the submount 14 via a variety of processes. In one embodiment, the laser diode 12 is bonded to the submount 14 via sintering. This ensures a strong bond of the laser diode 12 to the submount 14, strong thermal conduction between the laser diode 12 and the submount 14, and greater precision in the tolerances of the assembled first emitter subassembly 10 than can be achieved with other processes, such as soldering. The laser diode 12 may be bonded to the submount 14 at the P-side (or anode) of the laser diode that constitutes the laser diode 12.

[0014] FIG. 1b illustrates a second emitter subassembly 16. The second emitter subassembly 16 is similar to the first emitter subassembly 10 in that it also includes a laser diode 12 mounted on a submount 14. However, the second emitter subassembly further includes a second submount 14, thereby sandwiching the laser diode 12 between the submounts 14. As a result, the second emitter subassembly encapsulates the laser diode as a stand-alone unit while providing an opening through which the emitting edge of the laser diode 12 can emit light. In some embodiments, the laser diode 12 can be bonded to the second submount 14 of the second emitter subassembly 16 at the N-side (or cathode) of the laser diode 12.

[0015] FIG. 1c illustrates a laser stack 18 according to an embodiment of the present disclosure. The laser stack 18 includes a series of first emitter subassemblies 10 bonded together in parallel, with all of the emitting edges of the first emitter subassemblies facing the same general direction on one face of the stack. The stack is formed so that the optical output of each emitter subassembly is combined and concentrated into a smaller footprint to form a high-power laser. In some embodiments, the laser stack 18 can instead be configured to include a series of second emitter subassemblies 16 bonded together, with adjacent second emitter subassemblies 16 bonded via their submounts 14. Both laser stack embodiments are described in more detail below in FIGS. 3a and 3b.

[0016] FIG. 2 illustrates a cooler 20 according to an embodiment of the present disclosure. The cooler includes a plurality of metallized contacts 22 for transferring heat from the first or second emitter subassembly 10, 16 to the body of the cooler 20. The metallized contacts 22 are made of a thermally conductive material, and any thermally conductive material may be used as long as it is thermally conductive enough to transfer heat from the first or second emitter subassembly 10, 16 to the body of the cooler 20 based on the amount of heat generated by the emitter subassembly 10, 16. The cooler may use a coolant circulating within the body of the cooler 20 to transfer heat from both the cooler 20 and the laser stack. The cooler's equally spaced metallized contacts 22 are configured to match the spacing of the first or second emitter subassemblies in the laser stack, such that each metallized contact 22 is aligned with a corresponding emitter subassembly, as described in more detail below with reference to FIGS. 3a-3d.

[0017] FIG. 3a illustrates a cross-sectional view of a QCW laser 30 composed of first emitter subassemblies 10 bonded adjacent to and in parallel with one another. The first emitter subassemblies are also bonded to a cooler 20 via metallized contacts 22. FIG. 3a also illustrates a detailed view 32 shown enlarged in FIG. 3b. As shown in FIG. 3b, each first emitter subassembly 10 is configured to contact a metallized contact 22. The first emitter subassemblies 10 and metallized contacts 22 are arranged with an equal spacing (hereinafter referred to as a first pitch 34) between adjacent first emitter subassemblies 10 and metallized contacts 22, respectively. A consistent or repeatable pitch between adjacent first emitter subassemblies 10 and adjacent metallized contacts 22 is important to ensure high thermal performance of the cooler 20 because misalignment between the first emitter subassemblies 10 and the metallized contacts 22 can lead to reduced heat transfer from the laser diode 12, potentially causing laser damage, malfunction, or suboptimal laser performance. In other words, each pitch between adjacent subassemblies can be equidistant from adjacent pitches. As shown in FIG. 3b, the first pitch 34 represents the distance from one reference point on a first emitter subassembly 10 to the same reference point on an adjacent first emitter subassembly 10. Similarly, the first pitch 34 represents the distance from one reference point on a first metallized contact 22 of the cooler 20 to the same reference point on an adjacent metallized contact 22. While FIG. 3b illustrates that the first pitch 34 is the distance between the center points of the components, it will be readily understood that the first pitch 34 may be similarly measured or expressed as the same distance using a different reference point on either the first radiator subassembly 10 or the metallized contacts 22.

[0018] FIG. 3c illustrates a cross-sectional view of a QCW laser 36 composed of second emitter subassemblies 16 bonded adjacent to and in parallel with one another. The second emitter subassemblies 16 are also bonded to the cooler 20 via metallized contacts 22. FIG. 3c also illustrates a detailed view 38 shown enlarged in FIG. 3d. As shown in FIG. 3d, each second emitter subassembly 16 is configured to contact a metallized contact 22. The second emitter subassemblies 16 and metallized contacts 22 are arranged with a second pitch 39 between adjacent second emitter subassemblies 16 and metallized contacts 22, respectively. Similar to the embodiment illustrated in FIGS. 3a and 3b, a consistent pitch between adjacent second emitter subassemblies 16 and adjacent metallized contacts 22 ensures optimal thermal performance of the cooler 20. 3d, the second pitch 39 represents the distance from one reference point on a second radiator subassembly 16 to the same reference point on an adjacent second radiator subassembly 16. The second pitch 39 also represents the distance from one reference point on a first metallized contact 22 of a cooler 20 to the same reference point on an adjacent metallized contact 22.

[0019] 4a and 4b illustrate a lens array according to an embodiment of the present disclosure. Specifically, FIG. 4a illustrates a perspective view of the lens array 40 in which multiple lenses 42 are arranged adjacent to and parallel with one another, while FIG. 4b illustrates a cross-sectional view of the lens array 40. The lens array 40 is configured to be mounted on a QCW laser (e.g., QCW lasers 30, 36 in FIGS. 3a and 3c) to align with the emitting edge formed by the first or second emitter subassembly. The lenses 42 of the lens array 40 are arranged adjacent to one another at a pitch 44 that matches the pitch of the subassembly of the QCW laser to which it is mounted (e.g., first pitch 34 or second pitch 39 in FIGS. 3b and 3d). Because the pitch of the lenses 42 is equal to the pitch of the emitter subassembly, the lens array 40 can be mounted relatively easily compared to conventional systems and methods in which lenses are instead mounted individually. The process of individually attaching lenses can be particularly labor- and / or resource-intensive when the pitch between emitter subassemblies is small, e.g., only about 0.5 mm. Furthermore, the use of replicable pitches between emitter subassemblies, metallized contacts, and lenses enables the production of lens arrays, reducing production costs by eliminating the need to individually bond or attach lenses to each other and / or to the QCW laser.

[0020] It should be understood that Figures 4a and 4b are illustrative and do not depict the exact dimensions of the individual lenses 42 or lens array 40. Rather, the lens array 40 may be configured with various sizes and with various numbers of lenses 42 based on the particular specifications of the QCW laser. Similarly, the individual lenses 42 may have various dimensions based on the particular specifications of the QCW laser.

[0021] FIGS. 5a and 5b illustrate electron microscope scans 50 of an emitter subassembly bonded via sintering according to an embodiment of the present disclosure. FIG. 5a shows multiple laser diodes 52 and submounts 54 bonded with a sintered preform 58, which is shown in more detail in the detailed view 56 underlying the enlarged scan shown in FIG. 5b. FIG. 5b illustrates the sintered preform 58 positioned between the laser diodes 52 and the submount 54. The sintered preform 58 includes a solid silver layer 62 between two silver sintered film layers 60, 64. The three-layer sintered preform 58 is configured to be positioned between the laser diodes 52 and the submount 54 before the laser stack is compressed and heated. For comparison, FIG. 5b also illustrates a silver-tin solder joint 66. The silver-tin solder joint 66 may contain voids formed as a result of conventional soldering processes. These voids can be irregular in size and shape, causing variations in the solder joints throughout the laser stack. Furthermore, after reflow, different compositions of silver and tin are visible, with irregular shapes and / or layering. Thus, laser stacks formed using soldering instead of sintering may have overall dimensional tolerances that are too large for mounting a single lens array 40. Similarly, laser stacks formed using soldering instead of sintering may contain pitch variations between emitter subassemblies that make them unsuitable for mounting to a prefabricated cooler 20 or lens array 40. In comparison, joints formed from sintered preforms contain more predictable and regular pore sizes, providing greater precision when manufacturing laser stacks with tight tolerances. The resulting tolerances achieved via sintering versus soldering allow consistent pitch to be achieved throughout the emitter subassembly, further enabling separate fabrication of lens arrays and coolers with the same pitch. Furthermore, the overall dimensional tolerance of the finished laser stack can be more tightly controlled by varying the compressive force (measured as a compression ratio) applied to the laser stack during sintering, thereby compensating for variations in the sizes of subcomponents such as the laser diode and submount, and also variations in the size of the emitter subassembly.

[0022] The arrangement of laser diode 52 and submount 54 in Figures 5a and 5b is illustrative of the sintering process and joints described in embodiments of the present disclosure and should not be understood as accurately representing electron microscope scans of a completed laser stack. Similarly, the inclusion of solder joints in Figures 5a and 5b is for comparison and illustration purposes, and laser stacks formed in embodiments of the present disclosure may not include solder joints.

[0023] In some embodiments, sintered preforms of different compositions and types may be used to achieve similarly high-precision joints. For example, a single film (e.g., a single silver sintered film) may be used instead of a three-layer preform. In some embodiments, sintering paste may be applied between the laser diode and the submount and / or between the emitter subassembly. In some embodiments, sintered foil may be used. In some embodiments, copper and / or gold may be used as the sintered material. It will be readily understood that various compounds or elements may be used as nanoparticles that form the basis of the sintered material. Regardless of the means for providing the sintered material prior to compression and heating, or its specific composition, embodiments of the present disclosure achieve high-precision pitch tolerances through sintering, and it will be readily understood that the sintering process may involve some variation in how the sintered material is provided between the components and how they are subsequently fused to form the sintered joint.

[0024] In some embodiments, additional system and method steps may be implemented to ensure the laser stack is properly sintered. For example, pressure sensors may be used to monitor the pressure applied to opposing ends of the laser stack during sintering to ensure that pressure is applied evenly to opposite sides of the laser stack to provide uniform compression. Because the application of angled pressure during compression can cause misalignment of the radiator subassembly and / or subcomponents, quality control may be more easily performed to reduce manufacturing defects before they occur or to reject parts known to have been sintered using uneven pressure application. Pressure sensors may also be used to ensure that the proper compression ratio is maintained during sintering. In some embodiments, a compression ratio of 20-50% is used during sintering of the laser stack.

[0025] In some embodiments, temperature sensors may be used to monitor the temperature of the laser stack during sintering, thereby enabling temperature monitoring to ensure that all components of the laser stack achieve a sufficient temperature to complete the sintering process for a sufficient period of time. Internal, surface, and environmental temperature monitoring may also be utilized to prevent outgassing during sintering. In some embodiments, the clamps, presses, or vices used to compress the laser stack for sintering are preheated to promote heat propagation to the interior portions of the laser stack, thereby reducing the time required to achieve the sintering temperature at the innermost portion of the laser stack. For example, a press with two hot plates may be used, with one hot plate configured to be lowered toward the other to compress the laser stack.

[0026] In some embodiments, the pitch between emitter subassemblies within a laser stack can be variable, but is predefined. In such embodiments, the lens array is also configured with a variable pitch between individual lenses to match the predefined pitch of the laser stack. In this manner, lens arrays can still be used even if the pitches are not equidistant from one another, because bonding of the emitter subassemblies via sintering can be performed with sufficient precision to allow for the mounting of lens arrays with matching pitch configurations. In some embodiments, more than one lens array can be mounted on the laser stack instead of just a single lens array. For example, each lens array mounted on a laser stack can include two or more lenses, each with a predefined pitch or a predefined variable pitch between the lenses. The predefined pitch or predefined variable pitch is configured to match the predefined pitch or predefined variable pitch within a particular laser stack, so that individual mounting of lenses is not required, but more than one lens array may be needed. In this manner, a more versatile range of lasers can be produced by the methods disclosed herein. The use of variable pitch and / or two or more lens arrays increases the customizability of the laser stack and the feasible range of laser products that can be manufactured, while still achieving cost and time savings by eliminating the need for individual lens attachment.

[0027] It will be readily appreciated that a predefined pitch pattern can be used to define the distance at which the emitter subassemblies, lenses of the lens array, and metallized contacts are positioned relative to one another. In some embodiments, the predefined pitch pattern is simply a repeating pitch, or a pattern that defines all equal inter-component distances, as described above with reference to FIGS. 3a-3d and / or 4a-4b. This has the advantage of providing a simpler pattern that may require fewer lens arrays, may allow larger laser stacks to be produced while maintaining acceptable overall tolerances, and may reduce costs by reducing complexity. In some embodiments, the predefined pitch pattern defines inter-component distances that are variable. Because the predefined pitch pattern is used to define the distance between emitter subassemblies that matches the distance between lenses in one or more lens arrays, and because the same predefined pitch pattern can also be used to define the distance between metallized contacts, laser stacks can still be produced without individually attached lenses. This has the advantage of providing cost and time savings during laser stack production, while also enabling the production of more complex laser stacks.

[0028] While the subject matter of the present disclosure has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description should be considered illustrative or exemplary and not restrictive. Any statements herein characterizing the invention should be considered illustrative or exemplary and not restrictive, and the invention is defined by the claims. Those skilled in the art will understand that within the scope of the following claims, changes and modifications can be made which may include any combination of features from the different embodiments described above.

[0029] The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article "a" or "the" when introducing an element should not be construed as excluding a plurality of elements. Similarly, "or" listings should be construed as inclusive, so that a listing of "A or B" does not exclude "A and B" unless it is clear from the context or the foregoing description that only one of A and B is intended. Furthermore, a listing of "at least one of A, B, and C" should be construed as one or more of the group of elements consisting of A, B, and C, and should not be construed as requiring at least one of each of the listed elements A, B, and C, regardless of whether A, B, and C are related categorically. Furthermore, a listing of "A, B, and / or C" or "at least one of A, B, or C" should be construed as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B, and C.

Claims

1. 1. A light emitting device comprising: A plurality of radiator subassemblies, each radiator subassembly comprising: a plate-shaped light emitter having two sides and configured to emit light from an edge disposed between the two sides; at least one plate-shaped submount attached to at least one side of the plate-shaped light emitter; each of the plurality of emitter subassemblies are disposed parallel to one another and sintered together in a manner to form a light-emitting diode stack; a plurality of radiator subassemblies, the predefined pitch pattern defining the distance between adjacent radiator subassemblies; a lens array mounted on the light emitting diode stack, the lens array includes a plurality of lenses combined into a single unitary structure; a lens array, wherein the distance between the lenses corresponds to the distance defined by the predefined pitch pattern, such that each of the plurality of lenses is aligned with a corresponding one of the plate-shaped light emitters.

2. 2. The light emitting device of claim 1, wherein each of the plurality of emitter subassemblies includes two plate-shaped submounts, each attached to one of the two side surfaces of a respective plate-shaped light emitter.

3. 2. The light emitting device of claim 1, wherein each of the plurality of radiator subassemblies includes a plate-shaped submount attached to one of two sides of a respective plate-shaped light emitter, and the sintered portion between each of the plurality of radiator subassemblies is between the other of the two sides of each plate-shaped light emitter and the respective plate-shaped submount of an adjacent radiator subassembly.

4. 4. A light-emitting device according to claim 1, further comprising a cooler bonded to the light-emitting diode stack, the cooler having a plurality of cooling junctions arranged parallel to each other and with a relative distance from each other defined by the predefined pitch pattern, such that each of the plurality of cooling junctions is aligned with a respective one of the plurality of emitter subassemblies.

5. The light emitting device of any one of claims 1 to 4, further comprising a material sintered between each of the emitter subassemblies.

6. The light emitting device of claim 5 , wherein the sintered material comprises sintered silver.

7. 1. A method for forming a light emitting device, the method comprising: providing a plurality of plate-shaped light emitters, each having two sides and configured to emit light from an edge disposed between the two sides; providing a plurality of plate-shaped submounts; bonding each of the plurality of plate-shaped light emitters to at least one of two side surfaces of the plurality of plate-shaped submounts to form a plurality of emitter subassemblies; disposing each of the plurality of radiator subassemblies adjacent to and parallel to one another; and sintering each of the plurality of emitter subassemblies together to form a light-emitting diode stack, wherein the sintered emitter subassemblies are arranged at one or more predefined pitches relative to each other.

8. 8. The method of claim 7, further comprising attaching a lens array to the light-emitting diode stack, the lens array comprising a plurality of lenses combined into a unitary structure and arranged with the one or more predefined pitches between the lenses corresponding to the one or more predefined pitches of the sintered emitter subassembly.

9. The method of claim 7 or 8, further comprising providing a sintered preform between each radiator subassembly.

10. The method of claim 9 , wherein each of the sintered preforms comprises a solid silver layer between two silver sintered film layers.

11. determining a dimensional value of at least one dimension of the light emitting diode stack; 11. The method of claim 7, further comprising: varying a compression ratio applied to the light-emitting diode stack during sintering of the emitter subassemblies based on the determined dimensional values.

12. The method of any one of claims 7 to 11, further comprising providing a sintered film between each radiator subassembly.

13. The method of any one of claims 7 to 12, further comprising providing a sinter paste between each radiator subassembly.

14. 14. The method of any one of claims 7 to 13, further comprising bonding the sintered light-emitting diode stack to a cooler, the cooler having cooling junctions arranged parallel to one another and with the one or more predefined pitches between the cooling junctions corresponding to the one or more predefined pitches, so that each of the cooling junctions is aligned with a respective one of the emitter subassemblies.

15. The method of claim 14 , wherein the cooler and lens array are each separately pre-fabricated.

16. 16. The method according to claim 7, wherein the bonding step comprises bonding each of the plurality of plate-shaped light emitters to one of the plurality of plate-shaped submounts, such that the light-emitting diode stack comprises each of the plurality of plate-shaped light emitters and each of the plurality of plate-shaped submounts arranged in an alternating pattern.

17. The method according to any one of claims 7 to 15, wherein the bonding step comprises bonding each of the plurality of plate-shaped light emitters between two of the plurality of plate-shaped submounts.

18. 18. The method of any one of claims 7 to 17, further comprising preheating two plates prior to sintering the radiator subassembly, the two plates being configured to compress the radiator subassembly towards each other during sintering.

19. The method according to any one of claims 7 to 18, wherein the one or more predefined pitches are equal in length.

20. The method of any one of claims 7 to 19, wherein the one or more predefined pitches comprise at least two different lengths.

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