TWI907311B - Laser package structure - Google Patents

Abstract

A laser package structure is provided, including: a transparent substrate having a first face and a second face; a conductive layer arranged on the first face of the substrate; a plurality of laser chips having a respective light surface facing the first face of the substrate separately arranged and adhered to the conductive layer with an adhesion layer; a plurality of optical elements respectively corresponding to the plurality of laser chips and arranged between the conductive layer and the adhesion layer, or arranged on the second face of the substrate; a plurality of electrode pairs each of which including a first electrode and a second electrode, disposed on lower surfaces of the plurality laser chips; and a first conductive structure and a second conductive structure connecting to the conductive layer for electrical connection of the laser package structure to an external circuit board.

Description

Laser Packaging Structure

This invention relates to a laser packaging structure, and more particularly to a packaging structure for a vertical cavity surface-emitting laser (VCSEL) element with an integrated beam pattern.

Please refer to Figure 1. During the packaging process, the familiar laser chip 110 (e.g., a Vertical Cavity Surface Emitting Laser, VCSEL) is first die-bonded onto a ceramic substrate 100. After wire bonding to form wires 120, spacers 130 are placed around the laser chip 110 to form a separation space 140, which serves as an air layer. Then, optical components 150 are applied to complete the single-chip packaging process, forming the laser chip package structure 10, for subsequent connection to an external circuit board (not shown in the figure).

According to one embodiment of the present invention, a laser packaging structure includes: a transparent substrate having a first surface and a second surface; a conductive layer disposed on the first surface; a plurality of laser chips arranged side-by-side, each with its light-emitting surface facing the first surface, the plurality of laser chips being bonded to the conductive layer by an adhesive layer; a plurality of optical elements corresponding to the plurality of laser chips, located between the conductive layer and the adhesive layer, or located on the second surface of the transparent substrate; a plurality of electrode groups correspondingly disposed on the lower surfaces of the plurality of laser chips, each of the plurality of electrode groups including a first electrode and a second electrode; and a first conductive post and a second conductive post connected to the conductive layer, providing electrical connection of the laser packaging structure to an external circuit board.

10, 20, 20’, 20”, 20’’’, 30, 30’, 40, 40’, 50, 50’, 60, 60’: Laser Packaging Structure

12, 22, 32, 42, 52, 62: External circuit boards

64: First Laser Element

66: Second laser element

100: Ceramic substrate

110: Laser Chip

120: Route

130: Spacer

140: Separating Spaces

150: Optical Components

202, 302, 402, 502, 602: First laser chip

204, 304, 404, 504, 604: Second laser chip

212, 312, 412, 512, 612, 212', 312', 412', 512', 612': First electrode

214, 314, 414, 514, 614, 214', 314', 414', 514', 614': Second electrode

216, 316, 416, 516: Common electrode

210, 220, 320, 420, 520, 620, 675: Adhesive layer

230, 330, 430, 632, 634: Transparent substrate

230A, 330A, 430A, 530A, 632A, 634A: Surface

230B, 330B, 430B, 530B, 632B, 634B: Surface

240, 340, 440, 540, 640: conductive layer

252, 352, 452, 552, 652: First optical element

254, 354, 454, 554, 654: Second optical element

262, 362: first conductive pillar

264, 364: Second conductive pillar

270, 370, 470, 570: Protective layer

380, 480, 580, 680: Spacers

380A, 480A, 580A, 680A: Top surface

482, 582, 682: first conductive pillar

484, 584, 684: Second conductive pillar

385, 485, 585, 685: Spatial divisions

390, 490, 590, 690: Transparent substrate

390A, 490A, 590A, 690A: Surface

390B, 490B, 590B, 690B: Surface

600: Optical Component Assembly

5542, 6542: Substrate

5544, 6544: Graphics section

A: Light emission surface direction/light emission direction

D1: First distance

D2: Second distance

To further understand the features and technical content of this invention, please refer to the following detailed description of embodiments of this invention and the accompanying drawings. However, the detailed description and accompanying drawings are provided for reference and illustration only and are not intended to limit the invention; wherein: Figure 1 is a schematic cross-sectional view of a conventional laser element package structure.

Figures 2A and 2B are schematic cross-sectional views of the laser packaging structure according to the first embodiment and variations of the present invention.

Figures 2C and 2D are schematic cross-sectional views of a laser packaging structure according to the sixth embodiment and variations of the present invention.

Figures 3A and 3B are schematic cross-sectional views of the laser packaging structure according to the second embodiment and variations of the present invention.

Figures 4A and 4B are schematic cross-sectional views of the laser packaging structure according to the third embodiment and variations of the present invention.

Figures 5A and 5B are schematic cross-sectional views of a laser packaging structure according to the fourth embodiment and variations of the present invention.

Figures 6A and 6B are schematic cross-sectional views of a laser packaging structure according to the fifth embodiment and variations of the present invention.

The following description, with reference to the drawings and illustrative examples, illustrates the concepts of this invention. Similar or identical parts in the drawings and description use the same component symbols. Furthermore, the drawings are for ease of understanding; the thickness and shape of each layer in the drawings do not represent the actual dimensions or proportions of the components. It should be particularly noted that components not shown in the drawings or described in the specification are in a form familiar to those skilled in the art to which this invention pertains.

Please refer to Figures 2A and 2B, which are schematic cross-sectional views of the laser package structure according to the first embodiment of the present invention. The laser package structure 20 of this embodiment is a laser package structure with integrated optical patterns implemented using a wafer-level packaging (WLP) process. That is, at least two optical elements are integrated onto a chip in a single package structure. These two optical elements can be used to modify the optical pattern of the transmitted light, and these two optical elements correspond to different optical patterns.

The laser package structure 20 of this embodiment includes a first laser chip 202 and a second laser chip 204 for emitting laser light. The first laser chip 202 and the second laser chip 204 have a light-emitting surface (the light emission direction is shown by arrow A in the figure) and a lower surface opposite to the light-emitting surface. The first laser chip 202 has an electrode group composed of a first electrode 212 and a second electrode 214 on its lower surface to form an external electrical connection (i.e., an electrical connection to an external circuit board 22). The second laser chip 204 has an electrode group composed of a first electrode 212' and a second electrode 214' on its lower surface to form an external electrical connection. In this embodiment, the first electrode 212 and the second electrode 214 are n-electrodes and p-electrodes, respectively. However, in other embodiments, the first electrode 212 and the second electrode 214 may also be p-electrodes and n-electrodes, depending on whether the first electrode 212 and the second electrode 214 correspond to the p-semiconductor layer or the n-semiconductor layer of the first laser chip 202. In this embodiment, the first electrode 212' and the second electrode 214' are p-electrodes and n-electrodes, respectively. However, in other embodiments, the first electrode 212' and the second electrode 214' may also be, for example, n-electrodes and p-electrodes. The polarity of each first and second electrode depends on the actual design of the package structure and is not limited to the examples given.

On the other hand, regarding the first laser chip 202, although the diagram only shows the first laser chip 202 having one first electrode 212 and one second electrode 214, the first laser chip 202 may also have multiple first electrodes 212 or multiple second electrodes 214; furthermore, the size and shape of the first electrode 212 and the second electrode 214 may be the same or different, and are not limited to the diagram.

More specifically, taking a first laser chip 202 as an example, the first laser chip 202 includes a semiconductor stack, which includes an n-type semiconductor layer, an active layer, and a p-type semiconductor layer arranged sequentially from bottom to top. As mentioned above, the first electrode 212 and the second electrode 214 are, for example, an n-type electrode and a p-type electrode, respectively. The first electrode 212 is electrically connected to the n-type semiconductor layer, and the second electrode 214 is electrically connected to the p-type semiconductor layer through a via in the semiconductor stack. In another embodiment, the first laser chip 202 further includes at least two metal layers, respectively disposed below the n-type semiconductor layer and above the p-type semiconductor layer, and respectively electrically connected to the n-type semiconductor layer and the p-type semiconductor layer. The aforementioned vias, for example, penetrate the semiconductor stack, and the second electrode 214 is electrically connected to the metal layer on the p-type semiconductor layer via a conductive structure disposed in the via, thereby being electrically connected to the p-type semiconductor layer; or, the aforementioned vias, for example, penetrate the protective layer (not shown) outside the semiconductor stack, and the conductive structure in the via extends upward from the outside of the semiconductor stack to electrically connect to the p-type semiconductor layer. For example, an insulating layer is disposed in the via corresponding to the second electrode 214 to prevent the second electrode 214 or the corresponding conductive material from accidentally short-circuiting between the p-type semiconductor layer and the active layer of the first laser chip 202. The structure of the second laser chip 204 is similar to that of the first laser chip 202, and will not be repeated here.

In the embodiment shown in Figure 2A, the space between the adjacent sides of the first laser chip 202 and the second laser chip 204 is an air gap, without any other material filling it. In another embodiment, an insulating material is provided between the two sides of the first laser chip 202 and the second laser chip 204 to isolate them; the insulating material can also serve as a support. More specifically, the insulating material may only cover the sidewalls of the first laser chip 202 and the second laser chip 204, leaving a gap; or, the insulating material may fill the gap between the first laser chip 202 and the second laser chip 204. The light-emitting surfaces of the first laser chip 202 and the second laser chip 204 are bonded to a transparent substrate 230 via an adhesive layer 220. This transparent substrate 230 has a surface 230A facing the light-emitting surface of the laser chips and a surface 230B opposite to surface 230A. In this embodiment, a conductive layer 240 is provided on surface 230A of the transparent substrate 230. The first laser chip 202 and the second laser chip 204 are bonded to the conductive layer 240 on the transparent substrate 230 via the adhesive layer 220. The conductive layer 240 may include a straight line, a curved line, a patterned conductive line, or an unpatterned conductive layer; the structure of the conductive line is not limited herein.

In the embodiment described in Figure 2A, the laser package structure 20 further includes a first optical element 252 and a second optical element 254. As shown in Figure 2A, the first optical element 252 and the second optical element 254 are disposed on the surface 230B of the transparent substrate 230 and correspond to the first laser chip 202 and the second laser chip 204, respectively. The first conductive post 262 and the second conductive post 264 are connected to the conductive layer 240 of the transparent substrate 230, forming an electrical connection between the laser package structure 20 and the outside world. For example, the first conductive post 262 and the second conductive post 264 are electrically connected to an external circuit board 22 via electrodes 217 and 219, respectively.

The transparent substrate 230 is a transparent insulating material, such as glass, sapphire, SiC, Si, or GaAs. In one embodiment, the conductive layer 240 is made of a transparent conductive material, such as indium tin oxide (ITO), gallium zinc oxide (GZO), indium zinc oxide (IZO), or indium gallium zinc oxide (IGZO), to avoid blocking the light beams emitted from the first laser chip 202 and the second laser chip 204. In this embodiment, the conductive layer 240 covers an area of surface 230A that is not less than 10% and not more than 70% of the area of surface 230A. In another embodiment, the conductive layer 240 is made of a metal and surrounds a portion of the first surface along its outer periphery to avoid obstructing light emission from the element. In this embodiment, the conductive layer 240 covers an area of surface 230A that is no more than twenty percent of the area of surface 230A.

In this embodiment, the first optical element 252 and the second optical element 254 can be the same or different optical elements, and are selected from diffraction optical elements (DOE), microlens arrays, metalens, and combinations of the aforementioned optical elements. This allows the light beams emitted from the first laser chip 202 and the second laser chip 204 to be converted into uniform surface light sources, arrayed point light sources, or irregularly distributed point light sources, respectively.

According to the embodiments of the present invention, the first optical element 252 and the second optical element 254 can be elements independent of the transparent substrate 230 and the conductive layer 240, or they can be formed directly from the transparent substrate 230 through an appropriate process. For example, the patterns of the first optical element 252 and the second optical element 254 can be directly imprinted on the surface of the transparent substrate 230 (e.g., surface 230B) by nanoimprinting; or, the transparent substrate 230 can be directly patterned (e.g., etched) to form the first optical element 252 and the second optical element 254 directly on the surface of the transparent substrate (e.g., surface 230B); or a surface plating layer can be formed on the surface of the transparent substrate (e.g., surface 230B) to form the first optical element 252 and the second optical element 254, and the surface plating layer includes at least one of the materials suitable for optical thin films such as SiO2, SiNx, Al2O3, and TiO2. Furthermore, in this embodiment, the first optical element 252 and the second optical element 254 are formed on or located on the surface 230B of the transparent substrate 230; however, in other embodiments, the optical elements of the laser package structure of the present invention may also be located on the surface 230A side of the transparent substrate and on the conductive layer 240, that is, the conductive layer 240 is located between the transparent substrate 230 and the optical element.

The first laser chip 202 and the second laser chip 204 can be independent laser chips, or they can be formed by cutting a single chip at a predetermined pitch. By controlling the arrangement of the laser chips, the laser package structure of the present invention has an integrated optical pattern, which is a composite of one or more optical patterns. With this architecture, designers can arrange the components in the laser package structure to adjust the desired optical pattern, overcoming the problem that the optical pattern of previous laser package structures was determined by a single chip or a single optical element. In the embodiment shown in Figure 2A, the first laser chip 202 and the second laser chip 204 are formed by cutting a single chip at a predetermined pitch.

Furthermore, as shown in Figure 2B, in the laser package structure 20', the first laser chip 202 and the second laser chip 204 are not completely separated. In this embodiment, both the first laser chip 202 and the second laser chip 204 are electrically connected to an external electronic device via a common electrode 216. More specifically, the common electrode 216 corresponds to the aforementioned p electrode, and the first laser chip 202 and the second laser chip 204 each have first electrodes 212 and 212' as the aforementioned n electrode. In one embodiment, the first laser chip 202 and the second laser chip 204 each have a metal conductive layer, and the two metal conductive layers are interconnected. These two metal conductive layers may be the same metal conductive layer. A metal conductive layer is electrically connected to the p-type semiconductor layer of the first laser chip 202 and the p-type semiconductor layer of the second laser chip 204, and a portion of the metal conductive layer is exposed in the gap between the first laser chip 202 and the second laser chip 204. A conductive structure is disposed in the gap, and the conductive structure is electrically connected between the common electrode 216 and the metal conductive layer. The conductive structure and the common electrode can be formed by the same process or by different processes, which is not limited here. In this way, the common electrode is electrically connected to the p-type semiconductor layers of the first laser chip 202 and the second laser chip 204 respectively through the metal conductive layer. In Figure 2B, to avoid visual confusion, the specific structures of the first laser chip 202 and the second laser chip 204 are not described in detail. Instead, a simplified schematic diagram is used to show the interconnected portion between the first laser chip 202 and the second laser chip 204. This interconnected portion can be a metal conductive layer as described above.

Please refer to Figures 2C and 2D, which are schematic cross-sectional views of the laser package structure according to the sixth embodiment and variations of the present invention. Figures 2C and 2D respectively illustrate laser package structure 20” and laser package structure 20'''. The structures of laser package structure 20” and laser package structure 20''' are generally similar to those of the aforementioned laser package structure 20 or laser package structure 20'. Compared to laser package structure 20, in laser package structure 20”, the adhesive layer 220 is located on the conductive layer 240. Compared to laser package structure 20', in laser package structure 20''', the adhesive layer 220 is located on the conductive layer 240.

A plurality of optical elements corresponding to a plurality of laser chips (e.g., a first laser chip and a second laser chip) can be located on the upper or lower surface of the transparent substrate of the laser package structure, or formed directly from the transparent substrate, thereby forming an integrated light pattern output. Furthermore, considering process stability and efficiency, the optical elements can be located on the transparent substrate of the laser chips, or they can be placed on the package structure using a chip-scale package (CSP) process, as explained below.

Please refer to Figures 3A and 3B, which are schematic cross-sectional views of a laser package structure according to a second embodiment of the present invention. The laser package structure 30 of this embodiment includes a first laser chip 302 and a second laser chip 304 arranged side by side to emit laser light. The first laser chip 302 and the second laser chip 304 have a light-emitting surface (the light emission direction is shown by arrow A in the figure) and a lower surface opposite to the light-emitting surface. The first laser chip 302 and the second laser chip 304 each have an electrode group composed of first electrodes 312, 312' and second electrodes 314, 314' on their lower surfaces to form an external electrical connection (i.e., an electrical connection to an external circuit board 32). The configuration of electrodes 312, 314, 312', and 314' is similar to that of electrodes 212, 214, 212', and 214', and related details will not be repeated here. In the embodiment shown in Figure 3A, there is an air gap between the adjacent sides of the first laser chip 202 and the second laser chip 204, without any other material filling it. In another embodiment, an insulating material is provided between the two sides of the first laser chip 302 and the second laser chip 304 to isolate the first laser chip 302 and the second laser chip 304; the insulating material can also serve as a support. More specifically, the insulating material may only cover the sidewalls of the first laser wafer 302 and the second laser wafer 304, leaving a gap; or, the insulating material may fill the gap between the first laser wafer 302 and the second laser wafer 304. This transparent substrate 330 has a surface 330A facing the light-emitting surface of the laser wafer, and a surface 330B opposite to surface 330A and facing outwards.

In this embodiment, the laser package structure 30 further includes a housing/spacer 380 forming a partition space 385 around the front-disclosure wafer structure. This partition space 385 serves as an air layer for the laser package structure 30. The housing/spacer 380 has an upper surface 380A located on the light-emitting surface side of the laser wafer. Another transparent substrate 390 is coated on the upper surface 380A of the housing/spacer 380. In one embodiment, the material of the housing/spacer 380 includes at least one type of adhesive. In another embodiment, the material of the housing/spacer 380 is selected from the group consisting of ceramics, glass, and plastics. The above material selection is merely illustrative and is not limited thereto. The transparent substrate 390 has a surface 390A facing the light-emitting surface of the laser wafer (the light emission direction is shown by arrow A in the figure), and a surface 390B facing outwards from surface 390A. In this embodiment, a first optical element 352 and a second optical element 354 are disposed on surface 390A of the transparent substrate 390, and correspond to the first laser wafer 302 and the second laser wafer 304, respectively. By adjusting the height of the support member 380, the distance D1 between the first optical element 352 and the first laser wafer 302, and the distance D2 between the second optical element 354 and the second laser wafer 304, are adjusted accordingly.

Similarly, in this embodiment, the first laser chip 302 and the second laser chip 304 can be independent laser chips, or they can be formed by cutting the same chip at a certain pitch. By controlling the arrangement of the laser chips, the laser package structure of the present invention can have an integrated optical pattern. In the embodiment shown in Figure 3A, the first laser chip 302 and the second laser chip 304 are arranged side by side, and the sidewalls of the two are formed by cutting a single chip at a certain pitch. In another embodiment, a protective layer can also be provided between the first laser chip 302 and the second laser chip 304. In addition, the first laser chip 302 and the second laser chip 304 can also share a common electrode 316 through the arrangement of their electrodes, forming a laser package structure 30' as shown in Figure 3B. The details of the common electrode 316 are similar to those of the common electrode 216, and will not be repeated here.

Please refer to Figures 4A and 4B, which are schematic cross-sectional views of the laser package structure according to the third embodiment of the present invention. Overall, the laser package element 40 according to the present embodiment includes a first laser chip 402 and a second laser chip 404. The lower surfaces of the two laser chips are respectively provided with electrode groups including a first electrode 412 (e.g., a p electrode) and a second electrode 414 (e.g., an n electrode) for electrical connection of the first laser chip 402 and the second laser chip 404 to the outside (i.e., connection to an external circuit board 42), and are bonded to a transparent substrate 430 by an adhesive layer 420. The configuration of electrodes 412, 414, 412', and 414' is similar to that of electrodes 212, 214, 212', and 214'; related details will not be repeated here. The transparent substrate 430 has opposing surfaces 430A and 430B, wherein surface 430A faces the light-emitting surfaces of the first laser chip 402 and the second laser chip 404.

Similarly, in this embodiment, the laser package structure 40 further includes a housing/spacer 480 forming a partition space 485 around the front-disclosure wafer structure. This partition space 485 serves as an air layer for the laser package structure 40. The housing/spacer 480 has an upper surface 480A located on the side of the laser wafer's light-emitting surface. Another transparent substrate 490 is covered on the upper surface 480A of the housing/spacer 480. The transparent substrate 490 has a surface 490A facing the light-emitting surface of the laser wafer and an outward-facing surface 490B opposite to surface 490A. In this embodiment, the first optical element 452 and the second optical element 454 are disposed on the surface 490A of the transparent substrate 490 and correspond to the first laser wafer 402 and the second laser wafer 404, respectively. In one embodiment, the material of the support member 480 includes at least one type of adhesive. In another embodiment, the material of the support member 480 is selected from the group consisting of ceramics, glass, and plastics. The above material selection is merely illustrative and is not limited thereto.

The laser package structure 40 of this embodiment has a similar configuration to the aforementioned laser package structure 30. However, the difference lies in the fact that, in this embodiment, the conductive layer 440 is located on the transparent substrate 490 on which the first optical element 452 and the second optical element 454 are disposed. The support member 480 that forms the partition space 485 around the laser chip includes a conductive structure passing through it, such as the first conductive post 482 and the second conductive post 484, that is, it forms a conductive support member. By connecting the first conductive post 482 and the second conductive post 484 through the conductive layer 440, the laser package structure 40 can be electrically connected to the outside through this conductive support member, that is, electrically connected to an external circuit board 42. An insulating layer may be provided around the first conductive post 482 or the second conductive post 484 to prevent electrical connection errors in either post.

Similarly, in the embodiment shown in Figure 4A, the first laser chip 402 and the second laser chip 404 are arranged side-by-side, and their sidewalls are formed by cutting a single chip at a certain pitch. In this embodiment, the first laser chip 402 and the second laser chip 404 are separated by air. In another embodiment, a protective layer may be provided in the dicing channel, which may or may not completely fill the channel. Furthermore, the first laser chip 402 and the second laser chip 404 can also share a common electrode 416 through the arrangement of their electrodes. The relevant details of the common electrode 416 are similar to those of the common electrode 216 and will not be described again here.

Please refer to Figures 5A and 5B, which are schematic cross-sectional views of the laser package structure according to the fourth embodiment of the present invention. Overall, the laser package element 50 according to this embodiment includes a first laser chip 502 and a second laser chip 504. The lower surfaces of these chips are respectively provided with electrode groups including a first electrode 512 (e.g., a p-electrode) and a second electrode 514 (e.g., an n-electrode) for electrical connection of the laser chips 502 and 504 to the outside (i.e., connection to an external circuit board 52), and are bonded to a transparent substrate 530 by an adhesive layer 520. The arrangement of electrodes 512, 514, 512', and 514' is similar to that of electrodes 212, 214, 212', and 214'; related details will not be repeated here. The transparent substrate 530 has opposing surfaces 530A and 530B, wherein surface 530A faces the light-emitting surfaces of the first laser wafer 502 and the second laser wafer 504.

Similarly, in this embodiment, the laser package structure 50 further includes a housing/spacer 580 forming a partition space 585 around the front-disclosure wafer structure. This partition space 542 serves as an air layer for the laser package structure 50. The housing/spacer 580 has an upper surface 580A located on the side of the laser wafer's light-emitting surface. Another transparent substrate 590 is covered on the upper surface 580A of the housing/spacer 580. The transparent substrate 590 has a surface 590A facing the light-emitting surface of the laser wafer and an outward-facing surface 590B opposite to surface 590A. A first optical element 552 and a second optical element 554 are disposed on surface 590A of the transparent substrate 590 and correspond to the first laser wafer 502 and the second laser wafer 504, respectively. In this embodiment, the conductive layer 540 is located on the transparent substrate 590 on which the first optical element 552 and the second optical element 554 are disposed, and the support member 580 that forms the partition space 585 around the laser chip includes a conductive structure passing through it, such as the first conductive post 582 and the second conductive post 584, that is, forming a conductive support member. By connecting the first conductive post 582 and the second conductive post 584 through the conductive layer 540, the laser package structure 50 can be electrically connected to the outside through this conductive support member, that is, electrically connected to an external circuit board 52. An insulating layer may be provided around the first conductive post 582 or the second conductive post 584 to prevent incorrect electrical connection of the first conductive post 582 or the second conductive post 584. In one embodiment, the material of the support member 580 includes at least one type of adhesive. In another embodiment, the material of the support member 580 is selected from the group consisting of ceramics, glass, and plastics. The above material selection is merely illustrative and is not limited thereto.

The laser package structure 50 of this embodiment has a similar structure to the aforementioned laser package structure 40, except that in this embodiment, the second optical element 554 is composed of a transparent substrate 5542 and an optical element pattern portion 5544 formed on the transparent substrate 5542. By adjusting the thickness of the transparent substrate 5542, the distance D2 between the second optical element 554 and the second laser chip 504 can be adjusted accordingly, making it different from the distance D1 between the first optical element 552 and the first laser chip 502; wherein the selection of distances D1 and D2 depends on the function of the first optical element 552 and the second optical element 554.

In this embodiment, the first optical element 552 is a diffractive optical element (DOE), and the second optical element 554 is a microlens array (MLA). Each MLA has a separate pattern formed on its surface, and these patterns are independent and unaffected by each other, corresponding to the first laser chip 502 and the second laser chip 504, respectively. In this embodiment, the first optical element 552 and its corresponding first laser chip 502 are separated by a first distance D1, and the second optical element 554 and its corresponding second laser chip 504 are separated by a second distance D2. The first distance D1 is related to the focal length of the first optical element 552, while the second distance D2 is smaller than the first distance D1 due to the thickness of the transparent substrate 5542 of the second optical element 554. For example, in one embodiment, the first distance D1 is the focal length of the DOE and must be at least 2.2 mm; the second distance D2 can be adjusted by the thickness of the transparent substrate 5542, but it must be less than the first distance D1 and at least 0.5 mm.

Similarly, in the embodiment shown in Figure 5A, the first laser wafer 502 and the second laser wafer 504 are arranged side-by-side, and their sidewalls are formed by cutting a wafer at a certain pitch. In this embodiment, the first laser wafer 502 and the second laser wafer 504 are separated by air. In another embodiment, a protective layer may be provided in the dicing channel, which may or may not fill the dicing channel. Furthermore, the first laser wafer 502 and the second laser wafer 504 can also share a common electrode 516 through the arrangement of their electrodes. The relevant details of the common electrode 516 are similar to those of the common electrode 216 and will not be described again here.

Please refer to Figures 6A and 6B, which are schematic cross-sectional views of laser packaging structures according to five embodiments of the present invention. The difference between the laser packaging structure 60 of this embodiment and the laser packaging structures of the aforementioned embodiments is that, in this embodiment, an adhesive layer 675 separates the first laser element 64 and the second laser element 66. As shown in the figures, the first laser element 64 and the second laser element 66 each include: transparent packaging substrates 632 and 634, respectively. The transparent packaging substrate 632 has opposing surfaces 632A and 632B, and the transparent packaging substrate 634 has opposing surfaces 634A and 634B. Laser chips 602 and 604 are used to emit laser light. They are bonded to corresponding transparent packaging substrates 632 and 634 by adhesive layer 620, and their light-emitting surfaces face the surfaces 632A and 634A. The lower surfaces of laser chips 602 and 604 are provided with an electrode assembly including a first electrode 612 and a second electrode 614, which allows the first laser element 64 and the second laser element 66 to be electrically connected to the outside (i.e., electrically connected to an external circuit board 62). The configuration of electrodes 612, 614, 612', and 614' is similar to that of electrodes 212, 214, 212', and 214', and the relevant details will not be repeated here. The laser package structure 60 includes a support member 680 surrounding a first laser element 64 and a second laser element 66. The support member 680 includes conductive structures, such as a first conductive post 682 and a second conductive post 684, extending through it. The first conductive post 682 and the second conductive post 684 are connected to a conductive layer 640 for electrical connection of the laser package structure 60 to an external environment, such as an external circuit board 62. In one embodiment, the material of the support member 680 includes at least one type of adhesive. In another embodiment, the material of the support member 680 is selected from the group consisting of ceramics, glass, and plastics. The above material selection is illustrative only and is not limited thereto. In this embodiment, the optical element assembly 600 further includes a transparent substrate 690, which has a surface 690A and a surface 690B facing each other. Surface 690A faces the light-emitting surfaces of the first laser element 64 and the second laser element 66 (the light emission direction is shown by arrow A). The first optical element 652 and the second optical element 654 correspond to the first laser element 64 and the second laser element 66, respectively, and are located on surface 690A. The aforementioned conductive layer 640 is located on the first optical element 652 and the second optical element 654, and is connected to the external circuit board 62 via the first conductive post 682 and the second conductive post 684. An insulating layer may be provided around the first conductive post 682 or the second conductive post 684 to prevent electrical connection errors in the first conductive post 682 or the second conductive post 684.

Figure 6B illustrates a variation of the embodiment shown in Figure 6A. Similarly, in the embodiment shown in Figure 6B, the first laser element 64 and the second laser element 66 are also arranged side by side and separated by an adhesive layer 675, utilizing the stacking tolerances during the packaging process; however, the difference from the embodiment shown in Figure 6A is that, in this example, the second optical element 654 is composed of a transparent substrate 6542 and an optical element pattern portion 6544 formed on the transparent substrate 6542. By adjusting the thickness of the transparent substrate 6542, the distance D2 between the second optical element 654 and the second laser chip 604 can be adjusted accordingly, making it different from the distance D1 between the first optical element 652 and the first laser chip 602; wherein the selection of distances D1 and D2 depends on the function of the first optical element 652 and the second optical element 654.

In this embodiment, when the distance between the first laser chip 602 and the second laser chip 604 is relatively large due to packaging, the adjacent second electrode 614 and the first electrode 612 can share the same connecting pad p3 through wiring on the external circuit board 62, achieving the effect of a shared electrode.

In summary, this invention provides a laser packaging structure that integrates a traditional laser packaging structure onto a chip during the packaging process, thereby integrating at least two different optical elements within a single packaging structure. This provides a simple and feasible way to achieve a laser packaging structure with integrated optical patterns.

Furthermore, the laser packaging structure provided by this invention is a laser packaging structure with integrated optical patterns that reduces packaging size. It incorporates multiple optical elements, such as diffraction optical elements (DOEs), microlens arrays, metalens, and combinations of the aforementioned optical elements, above or below the flip-chip substrate of the laser chip. With independent control of each laser element, different optical functions, such as diffractors, dot projectors, or area light sources, can be realized within a single packaging structure.

In one embodiment, when the aforementioned optical element is an ultra-transparent lens, the distance between the lower surface of the optical element and the light-emitting surface of the laser chip (e.g., the aforementioned distance D1 or distance D2) is not less than 5 micrometers (μm) and not more than 200 micrometers. Preferably, the distance between the lower surface of the optical element and the light-emitting surface of the laser chip (e.g., the aforementioned distance D1 or distance D2) is not less than 10 micrometers and not more than 100 micrometers. As described in the foregoing embodiments, the height of the support can be adjusted to correspondingly adjust the distance between the optical element and the laser chip; alternatively, the optical element can be selectively positioned on the upper surface (where the transparent substrate is located between the laser chip and the optical element) or the lower surface (where the optical element is located between the laser chip and the transparent substrate) of the transparent substrate, as needed, to place the optical element in a suitable position without adding other components.

It should be noted that a superlens is constructed from a substrate and a fin array formed on the substrate (the substrate can be SiOx, TiO2, SiNx, or Al2O3). The refractive index of the superlens can be controlled and adjusted through the fin array, thus producing the same or different phase differences when light passes through different fin arrays. In integrated beam pattern designs, this ensures that all light reaches the focal point simultaneously, improving the imaging effect of the laser chip. Compared to conventional methods that require multiple lenses to eliminate errors, leading to an increase in the overall thickness of the laser package structure, using a superlens effectively reduces the overall thickness of the laser package structure, while simultaneously achieving miniaturization and precise imaging.

In this invention, by adjusting the wafer dicing pitch, a dual-function laser element is provided, which can be supplemented with a common electrode design and corresponding optical element control. This allows for the integration of multiple optical functions while reducing the package size and improving process reliability.

It should be noted that the aforementioned embodiments of this invention are merely illustrative and not intended to limit the scope of the invention. Various modifications and variations made to this invention by those skilled in the art to which it pertains do not depart from the spirit and scope of this invention. Identical or similar components in different embodiments, or components represented by the same element symbols in different embodiments, possess the same physical or chemical properties. Furthermore, where appropriate, the aforementioned embodiments of this invention can be combined or substituted with each other, and are not limited to the specific embodiments described above. The connection relationships between a specific component described in one embodiment and other components can also be applied to other embodiments, all of which fall within the scope of the appended patent application.

20 Laser Packaging Structure 22 External Circuit Board 202 First Laser Chip 204 Second Laser Chip 212 First Electrode 214 Second Electrode 220 Adhesive Layer 230 Transparent Substrate 230A Surface 230B Surface 240 Conductive Layer 252 First Optical Component 254 Second Optical Component 262 First Conductive Pillar 264 Second Conductive Pillar 270 Protective Layer

Claims (10)

A laser packaging structure includes: a transparent substrate having a first surface and a second surface; a plurality of laser chips arranged side-by-side, each with its light-emitting surface facing the first surface; a plurality of optical elements corresponding to the laser chips, located on the first surface of the transparent substrate and opposite to the laser chips, or located on the second surface of the transparent substrate, the optical elements including diffractive optical elements, microlens arrays, or superlenses; and a plurality of electrode groups correspondingly located on the lower surface of the laser chips, each electrode group including a first electrode and a second electrode, wherein the laser chips include a first laser chip and a second laser chip, at least one of the optical elements is a first optical element, at least one of the laser chips is a first laser chip, and a first distance exists between the first laser chip and the first optical element. At least one of the optical elements is a second optical element, at least one of the laser chips is a second laser chip, and there is a second distance between the second laser chip and the second optical element, wherein the first distance is related to the focal length of the first optical element, and the second distance is related to the focal length of the second optical element. The laser package structure as described in claim 1, wherein the optical elements are located on the second surface of the transparent substrate. The laser package structure as described in claim 1, wherein the first laser chip and the second laser chip share the first electrode. The laser packaging structure as described in claim 1 further includes a conductive layer located on the first surface of the transparent substrate, and at least one of the laser chips is bonded to the conductive layer by an adhesive layer. The laser packaging structure as described in claim 1, wherein the first distance is not equal to the second distance. The laser package structure as described in claim 1 further includes a support member located between at least two of the laser chips. The laser packaging structure as described in claim 1, wherein the first optical element is a diffracted optical element, the first distance is 2.2 mm or more, and the second distance is 0.5 mm or more and less than the first distance. The laser packaging structure as described in claim 1, wherein the first distance or the second distance is not less than 5 micrometers (μm) and not more than 200 micrometers. The laser package structure as described in claim 1, wherein the first optical element corresponds to the first laser chip to be converted into a first beam distribution light source, and the second optical element corresponds to the second laser chip to be converted into a second beam distribution light source, wherein the first beam distribution light source or the second beam distribution light source is a surface light source, an array of point light sources or an irregularly distributed point light source. The laser packaging structure as described in claim 9, wherein the first beam distribution light source is a surface light source and the second beam distribution light source is an array of point light sources.