Patent ID: 12262566

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

FIG.1Ais a schematic cross-sectional view of an optoelectronic module according to an embodiment of the disclosure. Please refer toFIG.1A, in the embodiment, an optoelectronic module10may be an optical ranging module. For example, the optical ranging module may be a time-of-flight (TOF) module or a proximity sensor. The optoelectronic module10includes a substrate20, a covering member30, a light emitting element40, and a light receiving element5.

In detail, the covering member30, the light emitting element40, and the light receiving element5are disposed on the substrate20, and the covering member30covers at least a portion of the substrate20, the light emitting element40and the light receiving element5. The covering member30includes an upper cover portion301, a peripheral sidewall portion302, and an inside partition33. The upper cover portion301is connected to the peripheral sidewall portion302and the inside partition33, wherein the upper cover portion301is substantially parallel to the substrate20, and the peripheral sidewall 1 portion302and the inside partition33are substantially perpendicular to the substrate20, wherein the inside partition33delimits a first cavity31and a second cavity32. That is, the upper cover portion301, the peripheral sidewall portion302, and the inside partition33jointly define the first cavity31and the second cavity32, and the inside partition33is located between the first cavity31and the second cavity32to separate the first cavity31from the second cavity32. The light emitting element40is disposed in the first cavity31and is configured to emit light with a wavelength toward an external object. The light receiving element5is mainly disposed in the second cavity32and is configured to receive and detect light reflected by the external object.

In the disclosure, the light emitting element40can be implemented, for example, as an infrared (IR) light emitting diode (LED), laser diode or vertical cavity surface emitting laser (VCSEL). Other types of light emitting elements may be used for some implementations. In some cases, the light emitting element may emit light at wavelengths different from IR. The light receiving element5may be a photo detector (PD) or a single-photon avalanche diode (SPAD) sensor chip, but not limited thereto. The embodiment takes the SPAD sensor chip as an example. The SPAD sensor chip90is made of a semiconductor material (e.g., silicon). The SPAD sensor chip90includes one or more electrical components (e.g., an integrated circuit). The integrated circuit may be an analog or digital circuit. Specifically, the SPAD sensor chip90includes the electrical components forming an application specific integrated circuit (ASIC). Accordingly, as commonly known by persons skilled in the art, the SPAD sensor chip90includes circuits for transmitting, receiving, and analyzing electrical signals.

Please refer toFIG.1A, in the embodiment, the SPAD sensor chip90includes a main optical sensor region50, which may be formed in the upper surface of the SPAD sensor chip90or coupled to the upper surface of the SPAD sensor chip90in other manners. The main optical sensor region50may be or include an array of light sensing elements, such as an array of photodiodes, an array of single-photon avalanche diodes (SPADs) or the like configured to detect the reflected light from the external object. In other embodiments, the SPAD sensor chip90further includes a reference optical sensor region60in addition to the main optical sensor region50. The reference optical sensor region60may be formed in the upper surface of the SPAD sensor chip90or coupled to the upper surface of the SPAD sensor chip90in other manners. The reference optical sensor region60is positioned near the light emitting element40and is configured to receive reference light emission, such as light emitted by the light emitting element40and reflected back to the reference optical sensor region60by a nearby surface (e.g., an inner wall surface of the upper cover portion301) with a known distance or optical path length. A reference optical sensor circuit (not shown) is formed in the SPAD sensor chip90near the reference optical sensor region60to process a signal generated by the reference optical sensor region60when a reflected reference light is received.

As shown inFIG.1A, the light emitting element40and the reference optical sensor region60are disposed in the first cavity31, and the main optical sensor region50is disposed in the second cavity32. In other words, the inside partition33separates the light emitting element40from the main optical sensor region50. Correspondingly, the inside partition33separates the reference optical sensor region60from the main optical sensor region50to prevent optical crosstalk. Light emitted by the light emitting element40is irradiated to the external object, then reflected toward the main optical sensor region50, and sensed by the main optical sensor region50and processed by the SPAD sensor chip90to obtain, for example, distance data to the external object or depth data of the external object.

In the embodiment, the covering member30includes a first opening34communicated with the first cavity31and a second opening35communicated with the second cavity32, wherein the light emitting element40is arranged corresponding to the first opening34, and the main optical sensor region50is arranged corresponding to the second opening35. The light, such as infrared light, emitted by the light emitting element40is projected from the first cavity31to the outside through the first opening34, and the infrared light reflected by the external object is incident into the second cavity32through the second opening35to be received by the main optical sensor region50. In detail, the optoelectronic module10further includes a first optical element70disposed in the first cavity31and a second optical element80disposed in the second cavity32, wherein the first optical element70is, for example, a diffuser or a diffractive optical element (DOE) and covers the first opening34. The second optical element80is, for example, a lens, Fresnel lens or a filter element and covers the second opening35. Therefore, the light emitted by the light emitting element40may pass through the first optical element70to form light rays with a uniform intensity distribution and a specific distribution. Additionally, the light reflected by the external object back into the second cavity32may pass through the second optical element80to be focused on and received by the main optical sensor region50.

FIG.1BtoFIG.1Dare schematic structural views of different implementations of an inner wall surface of a first cavity or a second cavity inFIG.1A. Please refer toFIG.1A, in the embodiment, the inside partition33has a first inner wall surface33alocated in the first cavity31and a second inner wall surface33blocated in the second cavity32. A first protruded-recessed structure R1is formed on the first inner wall surface33a,wherein the first protruded-recessed structure R1includes at least one protruded portion or recessed portion. That is, the first inner wall surface33ais not a substantially flat and smooth surface. For example, the first protruded-recessed structure R1has a plurality of protruded portions and a plurality of recessed portions existing in the first inner wall surface33a,which may be a stepped structure, an embossing, a microstructure, or a roughened structure after surface roughening processing (by a mechanical method or a chemical method) to prevent stray light from passing through the inside partition33from the first cavity31to enter the second cavity32, which can avoid the problems of optical crosstalk and signal-to-noise ratio reduction. Therefore, the optoelectronic module10has excellent sensing accuracy. For example, for the form of the first protruded-recessed structure R1of the first inner wall surface33a,reference may be made toFIG.1BtoFIG.1D. As can be seen from the drawings, the first protruded-recessed structure R1may include protruded portions3A and recessed portions3B, and the number and the structural form thereof are not limited thereto.

In addition, please refer toFIG.1A, taken along line II-II ofFIG.1A, the second cavity32is defined by the second inner wall surface33b,a third inner wall surface32aopposite to the second inner wall surface33b,a fourth inner wall surface32band a surface of the substrate20facing the fourth inner wall surface32band located between the second inner wall surface33band the third inner wall surface32a,wherein the fourth inner wall surface32bfacing the main optical sensor region50is connected between the second inner wall surface33band the third inner wall surface32a.A second protruded-recessed structure R2is formed on at least one of the second inner wall surface33b,the third inner wall surface32a,and the fourth inner wall surface32b,wherein the second protruded-recessed structure R2includes at least one protruded portion or recessed portion. In the embodiment, preferably, the second protruded-recessed structure R2has a plurality of protruded portions and a plurality of recessed portions existing in at least one the inner wall surface (e.g., the second inner wall surface33b,third inner wall surface32a,or fourth inner wall surface32b), which may be, for example, a stepped structure, an embossing, a microstructure, or a roughened structure after surface roughening processing (by a mechanical method or a chemical method) to prevent stray light from being reflected by the inner wall surface of the second cavity32to be incident into the main optical sensor region50, which can avoid the problem of the stray light being received by the main optical sensor region50and reduce signal noise. Therefore, the optoelectronic module10has excellent sensing accuracy. For example, for the form of the second protruded-recessed structure R2of at least one of the second inner wall surface33b,the third inner wall surface32a,and the fourth inner wall surface32b,reference may be made toFIG.1BtoFIG.1D. As can be seen from the drawings, the second protruded-recessed structure R2may include protruded portions3A and recessed portions3B, and the number and the structural form thereof are not limited thereto.

Please refer toFIG.1A, taken along line II-II ofFIG.1A, the first cavity31is defined by the first inner wall surface33a,a fifth inner wall surface31aopposite to the first inner wall surface33a,a sixth inner wall surface31band a surface of the substrate20facing the sixth inner wall surface31band located between the first inner wall surface33aand the fifth inner wall surface31a,wherein the sixth inner wall surface31bfacing the light emitting element40is connected between the first inner wall surface33aand the fifth inner wall surface31a.In the embodiment, relative to the first inner wall surface33a,the fifth inner wall surface31aand the sixth inner wall surface31bare substantially smooth. Further, the first inner wall surface33a, the second inner wall surface33b,the third inner wall surface32a,and the fifth inner wall surface31aare substantially perpendicular to the substrate20, and the fourth inner wall surface32band the sixth inner wall surface31bare substantially parallel to the substrate20. On the other hand, the first opening34penetrates the sixth inner wall surface31b,and the first optical element70is attached to the sixth inner wall surface31b.The second opening35passes through the fourth inner wall surface32b,and the second optical element80is attached to the fourth inner wall surface32b.In the embodiment, the second optical element80has a first optical surface81facing the second opening35and a second optical surface82opposite to the first optical surface81, and at least one of the first optical surface81and the second optical surface82is a focusing lens, a Fresnel optical surface, or an optical surface with microstructure. In an embodiment, the first optical surface81and the second optical surface82are both Fresnel optical surfaces. In another embodiment, the first optical surface81is a Fresnel optical surface, and the second optical surface82further includes an optical coating layer. Alternatively, in yet another embodiment, the first optical surface81includes an optical coating layer, and the second optical surface82is a Fresnel optical surface to improve transmittance or block light rays in a specific wavelength band from entering the second cavity32.

Please refer toFIG.1A, the SPAD sensor chip90disposed on the substrate20extends from the second cavity32to the first cavity31, and the main optical sensor region50and the reference optical sensor region60thereon are respectively located in the second cavity32and the first cavity31. In detail, the inside partition33of the covering member30extends from the upper cover portion301(i.e., from the interface between the fourth inner wall surface32band the sixth inner wall surface31b) to the substrate20, and the inside partition33passes locally above the SPAD sensor chip90(i.e., a portion of the end of the inside partition33is located above the top surface of the SPAD sensor chip90) to separate the main optical sensor region50from the reference optical sensor region60. On the other hand, the optoelectronic module10further includes a first light shielding layer103disposed between the inside partition33and the SPAD sensor chip90, and at least a portion of the end of the inside partition33may be bonded to the SPAD sensor chip90through the first light shielding layer103. In the embodiment, the first light shielding layer103may be, for example, an opaque glue, an opaque epoxy, an opaque tape, or opaque foam to prevent stray light from entering the second cavity32through a seam between the inside partition33and the SPAD sensor chip90, which can avoid the stray light being received by the main optical sensor region50to reduce optical crosstalk. On the other hand, the first light shielding layer103may also serve as a buffer to prevent the top surface of the SPAD sensor chip90from being crushed by the inside partition33during the process of assembling the covering member30.

FIG.2is a schematic cross-sectional view of an optoelectronic module according to another embodiment of the disclosure. Please refer toFIG.2, an optoelectronic module10A of the embodiment has substantially the same design as the optoelectronic module10shown inFIG.1A, and the difference between the two is that the optoelectronic module10A further includes a first radiation-filtering adhesive layer101, wherein the first radiation-filtering adhesive layer101can filter out a specific wavelength band. The first radiation-filtering adhesive layer101is attached to the fourth inner wall surface32baround the side edge surfaces of the second optical element80. More in detail, the side edge surfaces of the second optical element80are covered by the first radiation-filtering adhesive layer101, wherein the first radiation-filtering adhesive layer101may be configured to block or absorb light in a specific wavelength range, such as infrared light, to prevent stray light from entering the second cavity32through the edge of the second optical element80or a seam between the second optical element80and the fourth inner wall surface32b,which greatly reduces the stray light being received by the main optical sensor region50.

FIG.3is a schematic cross-sectional view of an optoelectronic module according to yet another embodiment of the disclosure. Please refer toFIG.3, an optoelectronic module10B of the embodiment has substantially the same design as the optoelectronic module10A shown inFIG.2, and the difference between the two is that the optoelectronic module10B further includes a second radiation-filtering adhesive layer102, wherein the second radiation-filtering adhesive layer102can filter out a specific wavelength band. The second radiation-filtering adhesive layer102is disposed on the substrate20around the side edge surfaces of the SPAD sensor chip90. More in detail, the side edge surfaces of the SPAD sensor chip90are covered by the second radiation-filtering adhesive layer102, wherein the second radiation-filtering adhesive layer102may be configured to block or absorb light in a specific wavelength range, such as infrared light, to prevent stray light from entering through the edge of the SPAD sensor chip90or a seam between the SPAD sensor chip90and the substrate20, which reduces the stray light received by the main optical sensor region50to greatly reduce optical crosstalk without affecting the signal-to-noise ratio.

On the other hand, the inside partition33includes a first section331connecting the upper cover portion301and a second section332located between the substrate20and the first section331, and a width W1of the first section331is greater than a width W2of the second section332. In detail, the first section331includes a protruded portion333extended outwardly and located in the first cavity31(relative to the first section331, the second section332includes a recessed portion335recessed inwardly and located in the first cavity31), that is, the first section331and the second section332constitute the first protruded-recessed structure R1. There is a gap G1between the bottom surface of the protruded portion333and the top surface of the SPAD sensor chip90. Further, the reference optical sensor region60is within an orthographic projection area of the protruded portion333on the substrate20. Therefore, the protruded portion333of the first section331may block stray light from entering the reference optical sensor region60, which prevents the stray light from being received by the reference optical sensor region60to improve the sensing accuracy. For example, the proportional relationship between the width W1of the first section331and the width W2of the second section332is W2<W1≤2W2, and the width W2is greater than or equal to 0.15 mm. In addition, there is a gap G2between the top surface of the upper cover portion301and the top surface of the SPAD sensor chip90, and the proportional relationship between the gap G1and the gap G2is 1/3G2≤G1≤1/2G2.

FIG.4Ais a schematic cross-sectional view of an optoelectronic module according to yet another embodiment of the disclosure. Please refer toFIG.4A, an optoelectronic module10C of the embodiment has substantially the same design as the optoelectronic module10shown inFIG.1A, and the difference between the two is that the optoelectronic module10C further includes an adhesive layer104disposed between the substrate20and the SPAD sensor chip90and further surrounding the side surfaces of the SPAD sensor chip90, wherein the adhesive layer104may be made of, for example, a glue with radiation-isolation feature for blocking light in a specific wavelength range, such as infrared light, and further covers the side surfaces of the SPAD sensor chip90to prevent stray light from entering through the side edge of the SPAD sensor chip90or the seam between the SPAD sensor chip90and the substrate20, which avoid the stray light being received by the main optical sensor region50. In sum, the SPAD sensor chip90may not only be bonded to the substrate20through the adhesive layer104, but may also greatly reduce the chance of optical crosstalk through the adhesive layer104.

FIG.4Bis a schematic cross-sectional view taken along line I-I ofFIG.4A. Please refer toFIGS.4A and4B, the end of the inside partition33includes a recess334facing the SPAD sensor chip90and adjacent to the top surface thereof, so that the inside partition33may span across the SPAD sensor chip90to be bonded to the substrate20. In addition, the optoelectronic module10C may further includes a second light shielding layer105disposed between the inside partition33and the substrate20and the SPAD sensor chip90, wherein the second light shielding layer105may be made of, for example, a glue with radiation-isolation feature for blocking light in a specific wavelength range, such as infrared light. In the embodiment, the recess334may provide an increased volume for accommodating the flow of the second light shielding layer105, thereby enhancing the coupling force. In sum, a portion of the second light shielding layer105is disposed in the recess334, so that the recess334of the inside partition33may be bonded to a non-functional region of the top surface of the SPAD sensor chip90through the second light shielding layer105. Similarly, the portion of the second light shielding layer105may also serve as a buffer to prevent the top surface of the SPAD sensor chip90from being crushed by the inside partition33during the process of assembling the covering member30. Another portion of the second light shielding layer105is located outside the recess334, and the end edges of the inside partition33are bonded to the substrate20through the second light shielding layer105. In other words, the second light shielding layer105can prevent stray light from entering the second cavity32through the seam between the inside partition33and the SPAD sensor chip90and a seam between the inside partition33and the substrate20in addition to closely fitting the end of the division portion33to the SPAD sensor chip90and the substrate20, which can avoid the stray light being received by the main optical sensor region50.

FIG.5is a schematic cross-sectional view of an optoelectronic module according to still another embodiment of the disclosure. Please refer toFIG.5, an optoelectronic module10D of the embodiment has substantially the same design as the optoelectronic module10C shown inFIG.4A, and the difference between the two is that the optoelectronic module10D further includes a second radiation-filtering adhesive layer102disposed on the substrate20and covering the side edge surfaces of the SPAD sensor chip90and the side edge surfaces of the adhesive layer104. In detail, the second radiation-filtering adhesive layer102can filter out a specific wavelength band, which may be made of a glue with radiation-isolation feature for blocking or absorbing light in a specific wavelength range, such as infrared light, to prevent stray light from entering the second cavity32through the edge of the SPAD sensor chip90, the seam between the SPAD sensor chip90and the substrate20, or the adhesive layer104, which can avoid the stray light being received by the main optical sensor region50.

FIG.6Ais a schematic cross-sectional view of an optoelectronic module according to yet another embodiment of the disclosure.FIG.6Bis a schematic view of a covering member inFIG.6A. Please refer toFIG.6AandFIG.6B, an optoelectronic module10E of the embodiment has substantially the same design as the optoelectronic module10shown inFIG.1A, and the difference between the two is that the inner wall surfaces, such as a fourth inner wall surface32b′ and a sixth inner wall surface31b′, of an upper cover portion301′ of a covering member30ainclude a first groove36communicated with the first opening34, a second groove37communicated with the second opening35, wherein the first and second grooves36,37constitute air vent. In addition, the covering member30afurther includes a first glue accommodating groove38and a second glue accommodating groove39, wherein the first groove36and the first glue accommodating groove38are located in the first cavity31, and the second groove37and the second glue accommodating groove39are located in the second cavity32. In detail, the first glue accommodating groove38and the first opening34are separated through a first protrusion303, and at the same time, the first glue accommodating groove38and the first groove36are separated through the first protrusion303. In addition, the second glue accommodating groove39and the second opening35are separated through a second protrusion304, and at the same time, the second glue accommodating groove39and the second groove37are separated through the second protrusion304. In the embodiment, the shapes of the first groove36and the second groove37are slightly funnel-shaped, but the shape and the number are not limited thereto.

Please refer toFIG.6AandFIG.6B, during the process of attaching the first optical element70and the second optical element80to the inner wall surfaces, such as a fourth inner wall surface32b′ and a sixth inner wall surface31b′, of the upper cover portion301′ of the covering member30athrough glue, air may then be vented to the outside through the first groove36and the first opening34, and the second groove37and the second opening35to reduce the pressure difference between the inside and the outside of the covering member30a, which prevents the first optical element70and the second optical element80from being damaged under pressure. On the other hand, the glue before curing is squeezed by the first optical element70and the second optical element80to flow, so the first glue accommodating groove38and the second glue accommodating groove39may provide space for glue before curing to flow. In addition, the first glue accommodating groove38provides an increased volume for accommodating the glue, thereby improving the strength of the first optical element70adhered to the upper cover portion301′ of the covering member30athrough the glue. Similarly, the second glue accommodating groove39provides an increased volume for accommodating the glue, thereby improving the strength of the second optical element80adhered to the upper cover portion301′ of the covering member30athrough the glue. In addition, in the embodiment, preferably, the inner wall surfaces of the upper cover portion301′ of the covering member30aare respectively formed with connecting portions305at four corners corresponding to the first optical element70and the second optical element80. The connecting portions305are configured to flatly attach the first optical element70and the second optical element80to the inner wall surfaces of the upper cover portion301′ of the covering member30a,respectively.

In summary, the first protruded-recessed structure is formed on the first inner wall surface of the inside partition located in the first cavity, which can prevent stray light from penetrating the inside partition from the first cavity where the light emitting element is located to enter the second cavity where the light receiving element/the main optical sensor region is located, thereby reducing optical crosstalk. On the other hand, the second protruded-recessed structure is formed on at least a portion of the inner wall surfaces of the second cavity, which can prevent stray light from being received by the light receiving element/the main optical sensor region after being reflected by the at least a portion of the inner wall surfaces. In addition, other traveling paths or other penetrating paths of stray light may be blocked or absorbed by adopting the radiation-filtering adhesive layer or the light shielding layer to greatly reduce the stray light being received by the light receiving element/the main optical sensor region. Therefore, the optoelectronic module of the disclosure can obtain a better signal-to-noise ratio, thereby having excellent sensing accuracy.

Finally, it should be noted that the above embodiments are only used to illustrate, but not to limit, the technical solutions of the disclosure. Although the disclosure has been described in detail with reference to the above embodiments, persons skilled in the art should understand that the technical solutions described in the above embodiments can still be modified or some or all of the technical features thereof can be equivalently replaced. However, the modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the disclosure.