Sensor package with light-guiding microstructure elements

Abstract

A sensor package includes a substrate, a light source, a light sensor, a cover, and a microstructure element. The light source and the light sensor are disposed on the substrate. The cover body covers the substrate and is provided with an accommodating space for accommodating the light source and the light sensor. The upper surface of the cover body is provided with a groove. The microstructure element is disposed within the recess to guide stray light in a direction away from the light sensor.

Description

Technical Field

[0001] The present invention relates to a sensor package, and more particularly to a sensor package in which a microstructure element is configured on the upper surface of the package body to redirect stray light away from a light sensor. Background Art

[0002] Please refer to Figure 1 , which is a cross-sectional view of a conventional sensor package 100. Sensor package 100 includes a light source 11 for illuminating an object in front of sensor package 100 through a first opening, and a light sensor 13 for receiving light reflected from the object through a second opening. A processor (not shown) can determine the presence and distance of the object based on the light signal detected by light sensor 13.

[0003] Generally, in order to prevent dust from entering the optical path of the sensor package 100, a protective glass 15 is disposed on the surface of the sensor package 100. Figure 1 As shown, part of the light beam emitted by the light source 11 will be internally reflected in the protective glass 15 and transmitted to the light sensor 13, thereby forming noise in the detection light signal.

[0004] Conventionally, a soft rubber layer may be disposed between the sensor package 100 and the protective glass 15 so that the protective glass 15 is closely attached to the rubber layer to reduce the reflected light energy.

[0005] However, since the rubber layer is made of a soft material, when the protective glass 15 is placed thereon, the rubber layer may be deformed at the opening and block the light path. At the same time, the rubber layer increases the overall height of the device.

[0006] The information disclosed in the background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the relevant information constitutes the prior art already known to those skilled in the art. Summary of the Invention

[0007] In light of this, the present invention provides a sensor package with a recessed top cover for accommodating a microstructured element. Because the thickness of the protective glass attached to the sensor package may vary depending on the product being used, the microstructured element can be replaced to accommodate the different protective glasses without having to re-manufacture the sensor package, simplifying the design process and reducing production costs.

[0008] The present invention provides a sensor package having an upper cover with a groove for disposing a microstructure element therein. The microstructure element may include a plurality of elongated prisms, glass bead reflectors or cube corner reflectors.

[0009] The present invention also provides a sensor package that does not require a soft rubber layer to be disposed between the upper cover and the protective sheet, thereby reducing the overall thickness.

[0010] The present invention provides a sensor package comprising a substrate, a light sensor, a light source, a cover, and a microstructure element. The light sensor is disposed on the substrate. The light source is disposed on the substrate and is located on a side of the light sensor in a first direction. The cover is disposed on the substrate and covers the light sensor and the light source. The cover includes a first through hole facing the light source, a second through hole facing the light sensor, and a groove located on the upper surface of the cover and between the first and second through holes. The microstructure element is disposed within the groove.

[0011] The present invention also provides a sensor package comprising a substrate, a light sensor, a light source, a cover, and a microstructure element. The light sensor is disposed on the substrate. The light source is disposed on the substrate and is located on one side of the light sensor in a first direction. The cover is disposed on the substrate and covers the light sensor and the light source, wherein the cover comprises a first through hole opposite to the light source, a second through hole opposite to the light sensor, and a groove located on the upper surface of the cover and between the first through hole and the second through hole. The microstructure element is disposed in the groove, wherein the lower surface of the microstructure element is a serrated surface and the upper surface is a flat surface, the flat surface being used to attach to a protective sheet placed on the upper surface of the cover.

[0012] The present invention also provides a sensor package comprising a substrate, a light sensor, a light source, a cover, and a microstructure element. The light sensor is disposed on the substrate. The light source is disposed on the substrate and is located on a side of the light sensor in a first direction. The cover is disposed on the substrate and covers the light sensor and the light source, wherein the cover includes a first through hole facing the light source, a second through hole facing the light sensor, and a flat top surface. The microstructure element is attached to the flat top surface and is interposed between the first through hole and the second through hole.

[0013] In order to make the above and other purposes, features and advantages of the present invention more apparent, the following will be described in detail with reference to the accompanying drawings. In addition, in the description of the present invention, the same components are represented by the same symbols and are hereby combined. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a cross-sectional view of stray light internal reflection formed in the protective glass of a known sensor package;

[0015] Figure 2 is a partially exploded schematic diagram of a sensor package according to an embodiment of the present invention;

[0016] Figure 3 is a perspective view of a sensor package according to an embodiment of the present invention;

[0017] Figure 4A is a top view of a microstructure element of a sensor package according to an embodiment of the present invention;

[0018] Figure 4B is another top view of the microstructure element of the sensor package according to an embodiment of the present invention;

[0019] Figure 4C yes Figure 4A and Figure 4B A cross-sectional view along line BB' in the microstructure element;

[0020] Figure 5 yes Figure 3 A cross-sectional view along line AA' in the sensor package;

[0021] Figure 6 is a schematic diagram of a glass bead reflector used as a microstructure element of a sensor package according to an embodiment of the present invention;

[0022] Figure 7 is a cross-sectional view of a sensor package according to another embodiment of the present invention;

[0023] Figure 8 is a cross-sectional view of a sensor package according to yet another embodiment of the present invention; and

[0024] 9A to 9D is a cross-sectional view of a microstructure element of a sensor package according to another embodiment of the present invention.

[0025] Description of Reference Numerals

[0026] 200, 300, 700, 800 sensor packages

[0027] 3110 base plate

[0028] 3130 Cover

[0029] 31 Light Source

[0030] 31R groove

[0031] 310, 330 filters

[0032] 33 Light Sensor

[0033] 35, 75, 85 microstructure elements

[0034] 90 protective glass

[0035] W1, W2 through holes DETAILED DESCRIPTION

[0036] The present invention provides a sensor package that utilizes microstructured elements to redirect stray light away from a light sensor, thereby reducing stray light noise and degrading light sensor performance. The microstructured elements of the present invention can be fabricated directly on the upper surface of the sensor package lid, attached to the upper surface of the sensor package lid, or placed within a recessed groove in the upper surface of the sensor package lid, effectively achieving the aforementioned objectives.

[0037] Please refer to Figure 2 FIG. 2 is a partially exploded schematic diagram of a sensor package 200 according to an embodiment of the present invention. The sensor package 200 includes a package body 21 and a microstructure element 25. The package body 21 includes a substrate 2110 and a cover 2130. The microstructure element 25 is configured in a groove 21R on the upper surface of the cover 2130, for example, Figure 3 shown. Figure 3 FIG3 is a perspective view of a sensor package 300 according to an embodiment of the present invention. Sensor package 300 also includes a package body 31 and a microstructure element 35 placed within recess 31R. Sensor package 300 differs from sensor package 200 in that the configuration of microstructure element 35 differs from that of microstructure element 25.

[0038] In one embodiment, the microstructure element 25 comprises a plurality of V-shaped elongated prisms arranged in parallel. Figure 2 As shown, a plurality of V-shaped corners (i.e., the intersection of the two sides of the V-shaped) are directed toward the light source (disposed in the first opening W1, refer to Figure 5 ) direction, for example Figure 2 The X-direction shown in FIG is the first direction. For example, the two sides of the plurality of V-shaped elongated prisms respectively have an angle θ with the first direction, and the angle θ is, for example, between 0 and 90 degrees. When the angle θ is 0 degrees, the following is formed: Figure 3 and 4B That is, in another embodiment, the plurality of elongated prisms of the microstructure element 35 form a second direction perpendicular to the first direction (eg Figure 3 Multiple parallel prisms in the Y-direction shown).

[0039] In another embodiment, the microstructure element 35' comprises a plurality of elongated prisms forming vertices (eg Figure 4Aa plurality of parallel curvilinear prisms in the first direction) with the midpoint of the curve thereof being a plurality of parallel curvilinear prisms in the first direction, Figure 4A The first direction is shown as the X-direction. That is, the plurality of vertices are aligned toward the light source (ie, along the first direction). The normal direction Dref of the reflective surface facing the light source side of the plurality of elongated prisms is referenced to Figure 4C As shown, they may be the same or different from each other, but all face a direction away from the light sensor to reflect stray light in a direction away from the light sensor.

[0040] For example, refer to Figure 9A and Figure 9B , which illustrates an embodiment in which the normal directions Dref of the reflective surfaces of the plurality of elongated prisms facing the light source are identical. Microstructure element 35A can be formed, for example, by attaching a prismatic sheet (each prism having a triangular cross-section) to a rectangular transparent sheet (of the same or different material as the prismatic sheet) or by injection molding to form an integrally formed structure. Microstructure element 35B can be formed, for example, by injection molding an integrally formed structure.

[0041] The cross section of the prism sheet is not limited to being triangular and directly connected to each other, for example, Figure 9C and Figure 9D As shown, the microstructure element 35C can be formed by attaching a prism sheet (with a semicircular cross section) to a rectangular transparent sheet (which is made of the same or different material as the prism sheet) or by injection molding to form an integrally formed structure; the microstructure element 35D can be formed by injection molding to form an integrally formed structure. In other embodiments, the prism is not limited to a continuous long strip, and can also be a plurality of separated prisms arranged adjacent to each other, for example, arranged in Figure 4A and 4B up and down directions.

[0042] For example, the planar portions (or bottom surfaces) of the microstructure elements 35A to 35D are fixed to the surface of the groove 31R by adhesive 350 .

[0043] Please also refer to Figure 3 and Figure 5 , Figure 5 yes Figure 3 A cross-sectional view of sensor package 300 taken along line A-A' is shown. Package 31 includes substrate 3110, light source 31, light sensor 33, and cover 3130. Light source 31, light sensor 33, and cover 3130 are all disposed on substrate 3110. A protective sheet 90 is placed on cover 3130 of sensor package 300. Due to assembly tolerances, a gap may exist between protective sheet 90 and the top surface of cover 3130, preventing a complete fit.

[0044] The substrate 3110 is, for example, a printed circuit board or a flexible substrate, and is not particularly limited.

[0045] The optical sensor 33 is electrically connected to the substrate 3110. The optical sensor 33 is, for example, a complementary metal oxide semiconductor (CMOS) image sensor or a single photon avalanche diode (SPAD) image sensor.

[0046] The light source 31 is a coherent light source, a partially coherent light source or a non-coherent light source, such as a light emitting diode or a laser diode. The light source 31 is located on one side of the first direction of the light sensor 33 (for example Figure 5 right direction).

[0047] The cover 3130 is made of an opaque material, which covers the light source 31 and the light sensor 33, and has a first through hole W1 and a second through hole W2 respectively opposite the light source 31 and the light sensor 33 to limit the illumination range and the light receiving range respectively. The cover 3130 has a first accommodating space for accommodating the light source 31, and the light source 31 emits light toward the outside of the sensor package 300 through the first through hole W1 above the first accommodating space. The cover 3130 has a second accommodating space for accommodating the light sensor 33, and the light sensor 33 receives reflected light from the outside of the sensor package 300 through the second through hole W2 above the second accommodating space, such as reflected light from an object in front of the cover 3130 of the sensor package 300, wherein the object is, for example, a part of the human body, but is not limited thereto. The light sensor 33 is built into a sensor chip, which includes a processor circuit, such as an application-specific integrated circuit (ASIC), a digital signal processor (DSP), or a field-programmable logic array (FPGA).

[0048] The cover 3130 further includes a recess 31R located on its upper surface, extending in the first direction between the first through hole W1 and the second through hole W2. In one embodiment, the upper surface is flat. Specifically, except for the first through hole W1, the second through hole W2, and the recess 31R, the remaining area of ​​the upper surface is flat.

[0049] Figure 3 and Figure 5 In the embodiment, the first through hole W1 is a first distance D1 from the groove 31R in the first direction; the second through hole W2 is a second distance D2 from the groove 31R in the first direction. In one embodiment, the first distance D1 and the second distance D2 are determined by the thickness of the protective sheet 90 placed on the upper surface of the cover 3130. When the thickness of the protective sheet 90 is greater, the distance of the light beam's internal reflection in the protective sheet 90 is longer, and the first distance D1 and the second distance D2 can be configured to be longer; conversely, when the thickness of the protective sheet 90 is smaller, the distance of the light beam's internal reflection in the protective sheet 90 is shorter, and the first distance D1 and the second distance D2 can be configured to be shorter. The internal reflection refers to the reflection of the light beam inside the protective sheet 90.

[0050] In another embodiment, the first distance D1 and the second distance D2 are kept constant, and only the width of the microstructure element 35 in the first direction is changed with respect to the different thicknesses of the protection sheet 90 .

[0051] In one embodiment, the bottom surface of the microstructure element 35 is a flat surface, which is bonded and fixed to the surface of the recess 31R via adhesive 350. Generally, the microstructure element 35 is made of a black material or a light-absorbing material, for example. Furthermore, by configuring the microstructure element 35 with multiple prisms, stray light that is not absorbed by the microstructure element 35 is reflected away from the light sensor 33 and does not enter the second through hole W2 and be received by the light sensor 33.

[0052] Sensor package 300 also includes filters 310 and 330, respectively, disposed at first through-hole W1 and second through-hole W2. Filters 310 and 330 are used to filter out wavelengths other than those emitted by light source 31. Filters 310 and 330 can be incorporated into cover 3130, or disposed within the first and second accommodating spaces, respectively, in front of light source 31 and light sensor 33, without particular limitation.

[0053] In addition to being composed of a plurality of elongated prisms, the microstructure element 35 can also be composed of glass bead reflectors or corner reflectors to achieve a reflective effect. Figure 6 As shown, in the embodiment where the microstructure element 35 includes glass beads 351 , it is preferred to further include silver glue 350 ′ laid on the bottom of the glass beads 351 (or covering the lower portion of the glass beads 351 ) to enhance the overall reflectivity.

[0054] In one embodiment, the depth of the groove 31R is greater than or equal to the height of the microstructure element 35 , so that the microstructure element 35 can be completely placed in the groove 31R.

[0055] Please refer to Figure 7 , which is a cross-sectional view of a sensor package 700 according to another embodiment of the present invention, also showing a cover protective sheet 90. The package of sensor package 700 also includes a substrate 3110, a light source 31, a light sensor 33, filters 310 and 330, and a cover 3130. Components of sensor package 700 that are identical to those of sensor package 300 are designated with the same reference numerals and are not further described here.

[0056] The primary difference between sensor package 700 and sensor package 300 is that the microstructure element 75 has a zigzag bottom surface and a flat top surface, which is designed to attach to a protective sheet 90 placed on the top surface of cover 3130. In this embodiment, the microstructure element 75 is preferably made of the same material as the protective sheet 90, such as glass or plastic. Consequently, when the top surface of the microstructure element 75 is attached to the protective sheet 90, stray light within the protective sheet 90 enters the microstructure element 75 and is reflected by the zigzag bottom surface away from the light sensor 33.

[0057] Similarly, the sawtooth surface may be formed by a plurality of elongated prisms arranged in parallel as a plurality of V-shaped prisms, as a plurality of parallel prisms arranged along a second direction (e.g., Y-direction) perpendicular to the first direction (e.g., X-direction), or as a plurality of parallel curved prisms with their apexes in the first direction. Figures 2 to 4B .

[0058] In one embodiment, the microstructured element 75 is bonded to the surface of the recess 31R using adhesive, and the depth of the recess 31R is less than the height of the microstructured element 75, so that the microstructured element 75 can protrude from the recess 31R to facilitate adhesion to the lower surface of the protective sheet 90. In one embodiment, the upper surface of the microstructured element 75 is bonded to the lower surface of the protective sheet 90 using transparent adhesive.

[0059] Please refer to Figure 8 , which is a cross-sectional view of a sensor package 800 according to yet another embodiment of the present invention, also showing a protective cover sheet 90. The package of sensor package 800 also includes a substrate 3110, a light source 31, a light sensor 33, filters 310 and 330, and a cover 3130'. Components of sensor package 800 that are identical to those of sensor package 300 are designated with the same reference numerals and are not further described here.

[0060] The primary difference between sensor package 800 and sensor package 300 is that microstructure element 85 is directly attached to the flat upper surface of cover 3130' and positioned between first through-hole W1 and second through-hole W2. That is, cover 3130' lacks a recess. First through-hole W1 is a first distance D1 from a first edge (e.g., the right edge) of microstructure element 85 in the first direction (e.g., the right side), while second through-hole W2 is a second distance D2 from a second edge (e.g., the left edge) of microstructure element 85 in the first direction.

[0061] Similarly, the first distance D1 and the second distance D2 are determined according to the thickness of the protection sheet 90 placed on the flat upper surface of the cover 3130 ′.

[0062] Sensor package 800 also includes a spacer 87 disposed between protective sheet 90 and the flat upper surface of cover 3130' to create a space for accommodating microstructure element 85. Spacer 87 can be made of, for example, rubber or plastic, without particular limitation. Spacer 87 can be disposed over all or part of the flat upper surface of cover 3130', depending on the application.

[0063] Figure 8 In one embodiment, the lower surface of the microstructure element 85 may be a serrated surface and the upper surface may be a flat surface, similar to Figure 7 Similarly, the sawtooth surface is composed of a plurality of elongated prisms, which are arranged into a plurality of parallel V-shaped prisms, a plurality of parallel prisms arranged along a second direction (e.g., Y-direction) perpendicular to a first direction (e.g., X-direction), or a plurality of parallel curved prisms with vertices in the first direction, for example, referring to Figures 2 to 4B .

[0064] Figure 8 In another embodiment, the lower surface of the microstructure element 85 is a plane and the upper surface is a serrated surface, similar to Figure 5 In this case, the sawtooth surface may be composed of a plurality of elongated prisms, as shown in FIG. 4 , or may be composed of glass bead reflectors or corner reflectors.

[0065] In the present invention, the protection sheet 90 can be formed of glass or plastic according to different applications.

[0066] In the present invention, the direction away from the optical sensor 33 includes a range from a direction toward the light source 31 (ie, a first direction) to a second direction perpendicular to the first direction, a range of 180 degrees.

[0067] It should be noted that while the grooves and microstructure elements shown in the present invention's drawings are rectangular, the present invention is not limited to this. In other embodiments, the grooves and microstructure elements may have other shapes, such as circular, elliptical, or trapezoidal. Furthermore, the microstructure elements may have different shapes from the grooves, as long as the microstructure elements can be placed within the grooves.

[0068] In summary, in conventional sensor packages, although the effect of reducing reflected energy can be achieved by configuring a soft rubber layer on the package, there is a problem that the soft rubber layer may deform at the opening and block the light transmission path. Therefore, the present invention further provides a sensor package (refer to Figure 5 、 Figure 7 and Figure 8 ), by configuring microstructure elements on the upper surface of the cover to direct stray light from the protective sheet away from the light sensor, so as to eliminate stray light noise and improve image quality.

[0069] Although the present invention has been disclosed through the aforementioned embodiments, they are not intended to limit the present invention. Any person skilled in the art with ordinary knowledge in the art to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A sensor package, comprising: substrate; a light sensor disposed on the substrate; a light source, the light source being disposed on the substrate and located on one side of the light sensor in the first direction; a cover body, the cover body being disposed on the substrate and covering the light sensor and the light source, wherein the cover body comprises a first through hole opposite to the light source, a second through hole opposite to the light sensor, and a groove located on an upper surface of the cover body and between the first through hole and the second through hole; as well as A microstructure element is configured in the groove.

2. The sensor package according to claim 1, wherein: The first through hole is a first distance away from the groove in the first direction, The second through hole is a second distance away from the groove in the first direction, and The first distance and the second distance are determined according to the thickness of the protection sheet placed on the upper surface of the cover.

3. The sensor package according to claim 2, wherein: The upper surface of the cover body has a region between the first distance and the second distance that is a plane.

4. The sensor package according to claim 1, wherein: The microstructure element includes a plurality of elongated prisms arranged into a plurality of parallel V-shaped prisms, a plurality of parallel prisms arranged along a second direction perpendicular to the first direction, or a plurality of parallel curved prisms with vertices in the first direction.

5. The sensor package according to claim 1, wherein: The bottom surface of the microstructure element is a plane, which is bonded to the surface of the groove by adhesive. The sensor package according to claim 1 , wherein: The microstructure elements include glass bead reflectors or corner reflectors.

7. The sensor package according to claim 1, wherein: The depth of the groove is greater than or equal to the height of the microstructure element.

8. A sensor package, comprising: substrate; a light sensor disposed on the substrate; a light source, the light source being disposed on the substrate and located on one side of the light sensor in the first direction; a cover disposed on the substrate and covering the light sensor and the light source, wherein the cover comprises a first through hole opposite to the light source, a second through hole opposite to the light sensor, and a groove located on an upper surface of the cover and between the first through hole and the second through hole; and A microstructure element is configured in the groove, wherein the lower surface of the microstructure element is a serrated surface and the upper surface is a flat surface, and the flat surface is used to be attached to a protective sheet placed on the upper surface of the cover.

9. The sensor package according to claim 8, wherein: The first through hole is a first distance away from the groove in the first direction, The second through hole is a second distance away from the groove in the first direction, and The first distance and the second distance are determined according to the thickness of the protection sheet.

10. The sensor package according to claim 9, wherein: The upper surface of the cover body has a region between the first distance and the second distance that is a plane.

11. The sensor package according to claim 8, wherein: The sawtooth surface is composed of a plurality of elongated prisms, which are arranged into a plurality of parallel V-shaped prisms, a plurality of parallel prisms arranged along a second direction perpendicular to the first direction, or a plurality of parallel curved prisms with vertices in the first direction.

12. The sensor package according to claim 8, wherein: The microstructure element is adhered to the surface of the groove by adhesive, and the depth of the groove is smaller than the height of the microstructure element.

13. A sensor package, comprising: substrate; a light sensor disposed on the substrate; a light source, the light source being disposed on the substrate and located on one side of the light sensor in the first direction; a cover body, the cover body being disposed on the substrate and covering the light sensor and the light source, wherein the cover body comprises a first through hole facing the light source, a second through hole facing the light sensor, and a flat upper surface; as well as A microstructure element is attached to the flat upper surface and is located between the first through hole and the second through hole.

14. The sensor package according to claim 13, wherein: The first through hole is a first distance away from the first edge of the microstructure element in the first direction, The second through hole is a second distance away from the second edge of the microstructure element in the first direction, and The first distance and the second distance are determined according to the thickness of the protection sheet placed on the flat upper surface of the cover. 15 . The sensor package according to claim 14 , further comprising a spacer, wherein the spacer is disposed between the protection sheet and the flat upper surface and is used to form a receiving space for accommodating the microstructure element.

16. The sensor package according to claim 13, wherein: The microstructure element includes a plurality of elongated prisms arranged into a plurality of parallel V-shaped prisms, a plurality of parallel prisms arranged along a second direction perpendicular to the first direction, or a plurality of parallel curved prisms with vertices in the first direction.

17. The sensor package according to claim 13, wherein: The microstructure elements include glass bead reflectors or corner reflectors.

18. The sensor package according to claim 13, wherein: The lower surface of the microstructure element is a sawtooth surface and the upper surface is a plane.

19. The sensor package according to claim 13, wherein: The lower surface of the microstructure element is a plane surface and the upper surface is a sawtooth surface.

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