Optical system and manufacturing method thereof

Abstract

The invention relates to an optical system and a manufacturing method thereof. The optical system includes a carrier, a light emitter, a light receiver, a block structure, and a package. And the light emitter is arranged on the bearing frame. The light receiver is disposed on the carrier and is physically spaced apart from the light emitter. The light receiver has a light detection area. The block structure is disposed on the carrier. The package is disposed on the carrier and covers the light emitter, the light receiver, and the block structure. The package has a recess over the block structure.

Description

[0001] Information about divisional applications

[0002] This application is a divisional application of the invention patent application with the application date of May 9, 2019, application number 201910385124.9, and invention name “Optical system and manufacturing method thereof”. Technical Field

[0003] The present disclosure relates to an optical system, and more particularly, to an optical system including a photodetector and a block structure. Background Art

[0004] In optical systems (e.g., optical scanning sensors, ranging sensors, background light sensing systems), light emitters (e.g., vertical cavity surface emitting lasers (VCSELs) or light emitting diodes (LEDs)) and / or light detectors are widely used. In some optical systems, packaging can be implemented to protect the light emitters or light detectors. However, some of the light emitted by the light emitter may be reflected at the boundary between the package and the air outside the package (e.g., interface reflection or total internal reflection), and the reflected light may be received by the light detector, resulting in unacceptable crosstalk problems and reducing the signal-to-noise ratio (SNR) of the optical system. Summary of the invention

[0005] According to one aspect of the present disclosure, an optical system includes a carrier, an optical transmitter, an optical receiver, a block structure, and a package. The optical transmitter is placed on the carrier. The optical receiver is placed on the carrier and physically separated from the optical transmitter. The optical receiver has a light detection area. The block structure is placed on the carrier. The package is placed on the carrier and covers the optical transmitter, the optical receiver, and the block structure. The package has a recess above the block structure.

[0006] According to another aspect of the present disclosure, an optical system includes a carrier, a light emitter, a light receiver, a block structure, and a package. The light emitter is disposed on the carrier. The light receiver is disposed on the carrier and is physically separated from the light emitter. The light receiver has a light detection area on a top surface of the light receiver. The package is disposed on the carrier and covers at least a portion of the light emitter and the block structure. The block structure is disposed between the light emitter and the light receiver. The block structure has a curved surface. The package has a recess above the block structure. The distance between the bottom surface of the recess and the carrier is less than the distance between the light detection area of ​​the light receiver and the carrier.

[0007] According to another aspect of the present disclosure, a method for manufacturing an optical system includes: (a) providing a carrier; (b) placing an optical transmitter on the carrier; (c) placing an optical receiver on the carrier, wherein the optical receiver is physically separated from the optical transmitter; (d) forming a package on the carrier to cover the optical transmitter and the optical receiver; and (e) forming a recess on the package block structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 shows a cross-sectional view of an optical system according to some embodiments of the present disclosure;

[0009] Figure 2A shows a cross-sectional view of an optical system according to some embodiments of the present disclosure;

[0010] Figure 2B A perspective view showing an optical system according to some embodiments of the present disclosure;

[0011] Figure 3A shows a cross-sectional view of an optical system according to some embodiments of the present disclosure;

[0012] Figure 3B shows a cross-sectional view of an optical system according to some embodiments of the present disclosure;

[0013] Figure 3C shows a cross-sectional view of an optical system according to some embodiments of the present disclosure;

[0014] Figure 3D shows a cross-sectional view of an optical system according to some embodiments of the present disclosure;

[0015] Figure 3E shows a cross-sectional view of an optical system according to some embodiments of the present disclosure;

[0016] Figure 4 shows a cross-sectional view of an optical system according to some embodiments of the present disclosure;

[0017] Figure 5A and Figure 5B A method for manufacturing an optical system according to some embodiments of the present disclosure is shown;

[0018] Fig. 6A , Figure 6B and Figure 6C A method for manufacturing an optical system according to some embodiments of the present disclosure is shown; and

[0019] Fig. 7A , Figure 7B , Figure 7C and Fig.7D A method of manufacturing an optical system according to some embodiments of the present disclosure is shown.

[0020] Common reference numerals are used throughout the drawings and detailed description to refer to the same or similar components.The present invention can be best understood from the following detailed description taken in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0021] Figure 1 1 shows a cross-sectional view of an optical system 1. The optical system 1 comprises a substrate 10, a light emitter 11, a light detector 12 and a cover 13. Figure 1 As shown, the cover 13 has a wall structure disposed between the light emitter 11 and the light detector 12. In some embodiments, the cover 13 includes an opaque material to prevent unwanted light emitted by the light emitter from being directly transmitted to the light detector. However, because the thickness of the cover 13 (e.g., thickness d1, d2, or d3) is relatively large (e.g., the total thickness of the cover 13 in the x-direction or y-direction increases by about 0.5 millimeters (mm), and the thickness in the z-direction is about 0.4 mm), the use of the cover 13 hinders the miniaturization of the optical system 1.

[0022] Figure 2A A cross-sectional view of an optical system 2 in some embodiments of the present disclosure is shown. The optical system 2 includes a carrier 20, a light emitter 21, a light receiver 22, a block structure (eg, baffle) 23, and a package 24.

[0023] The carrier 20 may include, for example, a printed circuit board, such as a paper-based copper foil laminate, a composite copper foil laminate, or a glass fiber-based copper foil laminate impregnated with a polymer (pp). The carrier 20 may include an interconnect structure, such as a plurality of conductive traces, pads, or perforations. In some embodiments, the carrier 20 includes a ceramic material or a metal plate. In some embodiments, the carrier 20 may include a substrate, such as an organic substrate or a lead frame. In some embodiments, the carrier 20 may include a double-layer substrate, the double-layer substrate including a core layer and a conductive material and / or structure disposed on the upper surface and the bottom surface of the carrier. The conductive material and / or structure may include a plurality of traces, pads, or through holes.

[0024] The light emitter 21 is disposed on the carrier 20. The light emitter 21 may include an emission die or other optical die. For example, the light emitter 21 may include a light emitting diode (LED), a laser diode, or another device that may include one or more semiconductor layers. The semiconductor layer may include silicon, silicon carbide, gallium nitride, or any other semiconductor material. The light emitter 21 may be connected to the carrier 20 by means of (for example) flip chip or wire bonding technology. In some embodiments, the light emitter 21 includes an LED die bonded to the carrier 20 by a die bonding material. The LED die includes at least one wire bonding pad. The LED die is electrically connected to the carrier 20 by a conductive wire, one end of the conductive wire is bonded to the wire bonding pad of the LED die, and the other end thereof is bonded to the wire bonding pad of the carrier 20. The light emitter 21 has an active area (or light emitting area) facing away from the carrier 20.

[0025] The optical receiver 22 is disposed on the carrier 20 and physically spaced apart from the optical transmitter 21. In some embodiments, the optical receiver 22 includes, for example, a PIN diode (a diode including a p-type semiconductor region, an intrinsic semiconductor region, and an n-type semiconductor region) or a photodiode or a phototransistor. In some embodiments, the optical receiver 22 not only detects light from the optical transmitter 21, but also includes some different sensing areas with a filter structure for ambient light sensing (ALS). The optical receiver 22 can be connected to the carrier 20, for example, by means of a flip chip or wire bonding technology (e.g., by bonding wires 23w). The optical receiver 22 has an active area 22d (or light detection area) facing away from the carrier 20. In some embodiments, the optical receiver 22 may include a controller, a processor, a memory, an application specific integrated circuit (ASIC), and the like.

[0026] The block structure (e.g., baffle) 23 is disposed on the carrier 20 and spans a portion of the light receiver 22 where the non-light detection region 22d is located. For example, the block structure 23 is disposed across other circuits integrated into the light receiver 22. In some embodiments, the block structure 23 may be disposed across a portion of the bonding wire 23w that connects the light receiver 22 to the carrier 20, such as Figure 2B As shown in Figure 2B Show Figure 2A 2 is a perspective view of the optical system 2 in FIG. 2. In some embodiments, the block structure 23 may cover a portion of the side wall of the light receiver 22. In some embodiments, the ratio of the width of the bottom surface of the block structure 23 to the height of the block structure 23 is about 2:1. In some embodiments, the block structure 23 may have a curved structure 23c located at or adjacent to the top side of the block structure 23.

[0027] In some embodiments, the block structure 23 includes an opaque material or a light-absorbing material to prevent the light emitted by the light emitter 21 from directly transmitting to the light receiver 22. Figure 2A As shown in FIG. 2 , light L1 detected by the optical receiver 22 is reflected by the target object 25, while light L2 reflected at the boundary of the package 24 and the air outside the package 24 (e.g., interface reflection) is blocked by the block structure 23. Therefore, the crosstalk problem between the optical transmitter 21 and the optical receiver 22 can be eliminated or alleviated, so that the SNR of the optical system 2 can be increased.

[0028] In some embodiments, the light is reflected at the boundary between package 24 and the air outside package 24 and is Figure 2A or Figure 2B The power of light received by the optical receiver 22 in the optical system is about 1% to 5% less than the power of light in the optical system without the block structure. For example, the light reflected at the boundary of the package 24 and the air outside the package 24 and Figure 2A or Figure 2B The power of light received by the light receiver 22 in the optical system 2 may be about 0.063 microwatts (μW) in the case of having the block structure 23, and may be about 1.68 μW in the case of not having the block structure 23. In addition, since a cover is not required in the optical system 2 to avoid crosstalk between the light transmitter 21 and the light receiver 22, Figure 2A or Figure 2B The area and thickness of the optical system 2 can be reduced, thereby achieving a compact package size.

[0029] The package 24 is placed on the carrier 20 and covers the light emitter 21, the light receiver 22 and at least a portion of the block structure 23. In some embodiments, a portion (e.g., a top surface) of the block structure 23 is exposed from the package 24. The top surface of the block structure 23 is substantially coplanar with the top surface of the package 24. In other embodiments, the block structure 23 may be completely covered by the package 24. In some embodiments, the package 24 includes a light-transmitting material. For example, the package 24 is a transparent compound. For example, the package 24 includes epoxy resin.

[0030] Figure 3A A cross-sectional view of an optical system 3A in some embodiments of the present disclosure is shown. The optical system 3A is similar to Figure 2A The optical system 2, except Figure 3A The block structure 23 in FIG. 2 is not disposed across the light receiver 22. For example, the block structure 23 is disposed between the light emitter 21 and the light receiver 22 and is spaced apart from the light emitter 21 or the light receiver 22.

[0031] Figure 3B A cross-sectional view of an optical system 3B in some embodiments of the present disclosure is shown. Optical system 3A is similar to Figure 3A The optical system 3A in, the differences between them are described below.

[0032] like Figure 3BAs shown in , the package 24 has a recess 24r. The recess is disposed between the light emitter 21 and the light receiver 22. The recess 24r is disposed above the block structure 23. In some embodiments, the recess 24r exposes the block structure 23. In other embodiments, the lower side (e.g., bottom surface or bottom side) of the recess 24r is spaced apart from the block structure 23. In some embodiments, the lower side of the recess 24r may be smaller than, equal to, or larger than the active area 22d of the light receiver 22 according to different design requirements.

[0033] In some embodiments, the optical receiver 22 is electrically connected to the carrier 20 via a bonding wire 23. Since the bonding wire 23 requires space (e.g., a wire loop), the thickness of the package 24 has a minimum limit. For example, there should be a gap between the top surface of the package 24 and the optical receiver 22 to accommodate the bonding wire 23. In addition, as mentioned above, the ratio of the width of the bottom surface of the block structure 23 to the height of the block structure 23 should follow a rule (e.g., 2:1), so if the height of the block structure 23 is designed to be the same as the thickness of the package 24, then the width of the block structure 23 will be relatively large, which will increase the area occupied by the block structure 23 (increase the package size). However, if the height of the block structure 23 is designed to be less than the thickness of the package 24 (e.g., there is a gap between the top surface of the package 24 and the top surface of the block structure 23), then the light emitted from the optical transmitter 21 can directly enter the optical receiver 22, which will cause unacceptable crosstalk problems and reduce the SNR.

[0034] According to Figure 3B In the embodiment shown in , a recess 24r is formed above the block structure 23, and the light (e.g., L33) emitted by the light emitter 21 can be refracted twice by the recess 24r, wherein one refraction occurs when the light is emitted from the package 24 to the outside of the package 24, and the other refraction occurs when the light is emitted from the outside of the package 24 to the package 24. Therefore, the power of the light emitted by the light emitter 21 and directly entering the active area 22d of the light receiver 22 can be reduced. For example, the light emitted by the light emitter 21 and directly entering the active area 22d of the light receiver 22 (e.g., Figure 3B The power of light emitted by the light emitter 21 and directly entering the active area 22d of the light receiver 22 can be reduced by 80% compared to the power of light in the structure without the recess 24r formed above the block structure 23. Therefore, by forming the recess 24r above the block structure 23, the power of light emitted by the light emitter 21 and directly entering the active area 22d of the light receiver 22 can be reduced without increasing the height of the block structure 23. In addition, the block structure 23 includes an opaque material or a light-absorbing material to prevent the light emitted by the light emitter 21 from being directly transmitted to the light receiver 22 (for example, through the path L34).

[0035] Figure 3C A cross-sectional view of an optical system 3C in some embodiments of the present disclosure is shown. The optical system 3C is similar to Figure 3B The optical system 3B, except Figure 3C The shape of the recess 24r in the Figure 3B In some embodiments, the shape of the recess 24r can be designed according to different design requirements. In some embodiments, the bottom surface of the recess 24r is spaced apart from the block structure 23. For example, there is a gap between the recess 24r and the block structure 23.

[0036] Figure 3D A cross-sectional view of an optical system 3D in some embodiments of the present disclosure is shown. Figure 3D The optical system in 3D is similar to Figure 3A The optical system 3A, except Figure 3D The package 24 of the optical system 3D in the embodiment has a recess 24r for exposing the top surface of the block structure 23. For example, the top surface of the package 24 is not coplanar with the top surface of the block structure 23. In some embodiments, Figure 3D The hardness of the block structure 23 is greater than Figure 2A or Figure 3A In some embodiments, the bottom surface of the recess 24r is substantially coplanar with the top surface of the block structure 23. For example, the top surface of the block structure 23 is exposed from the recess 24r. In some embodiments, the width of the recess 24r may be equal to or greater than the width of the block structure 23.

[0037] Compared to Figure 3C The optical system 3C, Figure 3D The top surface of the block structure 23 in the embodiment is exposed from the recess, which can prevent the light emitted by the light emitter 21 from being directly transmitted to the light receiver 22. Figure 3D As shown in FIG, light L31 reflected at the boundary of the package 24 and the air outside the package 24 (e.g., interface reflection) is blocked by the block structure 23. Therefore, the crosstalk problem between the optical transmitter 21 and the optical receiver 22 can be eliminated or alleviated, thereby increasing the SNR of the optical system 3D.

[0038] Figure 3E A cross-sectional view of an optical system 3E in some embodiments of the present disclosure is shown. Figure 3E The optical system 3E in is similar to Figure 3D The differences between them are described below.

[0039] In some embodiments, Figure 3E The width of the recess 24r is smaller than the width of the block structure 23. Figure 3EAs shown in , the block structure 23 may have a cut surface 24r1 exposed from the package 24. The cut surface 24r1 of the block structure 23 is recessed from other portions of the block structure 23 surrounding the cut surface 24r1. In some embodiments, the recess 24r may be defined by the cut surface 24r1 and at least a portion of the block structure 23. As an example, at least a portion of a sidewall of the recess 24r may be defined by a portion of the block structure 23. In some embodiments, the portion of the block may at least partially surround the cut surface 24r1 and be exposed from the package 24.

[0040] Figure 4 A cross-sectional view of an optical system 4 in some embodiments of the present disclosure is shown. Figure 4 The optical system 4 in is similar to Figure 2A The optical system 2, except Figure 4 The package 24 of the optical system 4 in FIG. 4 has a recess 24r for exposing the top surface of the block structure 43. For example, the top surface of the package 24 is not coplanar with the top surface of the block structure 43.

[0041] like Figure 4 As shown in FIG. 2 , light L41 reflected at the boundary of package 24 and the air outside package 24 (e.g., interface reflection) is blocked by block structure 23. Therefore, the crosstalk problem between light emitter 21 and light receiver 22 can be eliminated or alleviated, thereby increasing the SNR of optical system 4. In some embodiments, the power of light reflected at the boundary of package 24 and the air outside package 24 and received by light receiver 22 can be about 0.028 μW.

[0042] Figure 5A and Figure 5B A method for manufacturing an optical system according to some embodiments of the present disclosure is shown. In some embodiments, Figure 5A and Figure 5B The method used to make Figure 2A The optical system 2.

[0043] refer to Figure 5A , a carrier 20 is provided. The light emitter 21 and the light receiver 22 are placed on the carrier 20 and physically spaced apart from each other. The block structure 23 is formed on the carrier 20 and across a portion of the light receiver 22 where the non-light detection area 22d is located. In some embodiments, the block structure 23 can be formed by dispensing an opaque material on the carrier 20 and the portion of the light receiver 22 where the non-light detection area 22d is located. In some embodiments, the block structure 23 includes silicon, epoxy resin, or any other suitable material (e.g., an opaque material or a light absorbing material). In some embodiments, the block structure 23 is relatively soft or flexible. For example, the block structure 23 can be formed of a material having a hardness of Shore A50 or greater.

[0044] Next, the mold tool 50 with the film 50f is moved toward the carrier 20 to form a package 24 covering the light emitter 21, the light receiver 22 and the block structure 23, thereby forming the optical system 2, as shown in FIG. Figure 5B . In some embodiments, the mold compound 24 is formed by a compression molding process. Because the support structure 23 is relatively soft or pliable, when the mold tool 50 is pressed on the block structure 23, the block structure 23 will be compressed. Therefore, there is no gap between the top surface of the block structure 23 and the top surface of the package 24. In other words, the top surface of the block structure 23 is substantially coplanar with the top surface of the package 24.

[0045] Fig. 6A , Figure 6B and Figure 6C A method of manufacturing an optical system according to some embodiments of the present disclosure is shown according to a cross-sectional view. Fig. 7A , Figure 7B , Figure 7C and Fig.7D A method for manufacturing an optical system according to some embodiments of the present disclosure is shown according to a perspective view. In some embodiments, Fig. 6A , Figure 6B and Figure 6C or Fig. 7A , Figure 7B , Figure 7C and Fig.7D The method used to make Figure 4 The optical system 4.

[0046] refer to Fig. 6A or Fig. 7A , a carrier 20 is provided. The light emitter 21 and the light receiver 22 are placed on the carrier 20 and are physically separated from each other. Fig. 7A As shown in FIG. 1 , the light receiver 22 is connected to the carrier 20 via a bonding wire 22w. A block structure 43′ is formed on the carrier 20 and is positioned across a portion of the non-light detection area 22d in the light receiver 22. In some embodiments, the block structure 43′ is positioned across a portion of the bonding wire 22w, such as Figure 7B In some embodiments, the block structure 43' may cover a portion of the side wall of the light receiver 22. In some embodiments, the block structure 43' may be formed by dispensing an opaque material on the portion of the carrier 20 and the light receiver 22 where the non-light detection area 22d is located. In some embodiments, the block structure 43' comprises silicon, epoxy, or any other suitable material (e.g., an opaque material or a light absorbing material). In some embodiments, the block structure 43' is relatively hard. For example, Fig. 6A The block structure 43' is Figure 5A For example, the block structure 43' may be formed of a material having a Shore C or greater hardness such as Shore D90.

[0047] Next, the mold tool 50 with the film 50f is moved toward the carrier 20 to form a package 24 covering the light emitter 21, the light receiver 22 and a portion of the block structure 43', thereby forming an optical system, such as Figure 6B or Figure 7C In some embodiments, the package 24 is formed by a compression molding process. Because the block structure 43' is relatively hard, the block structure 43' will not deform when the mold tool 50 is pressed on the block structure 43'. Figure 6B As shown in FIG. 4 , the block structure 43' protrudes from the top surface of the package 24. The film 50f is formed of a soft material to provide a buffer for the block structure 43' to prevent cracking.

[0048] refer to Figure 6C or Fig.7D A cutting operation (e.g., half-cutting) is performed to remove a portion of the block structure 43' and a portion of the package to form a recess 24r. The top surface of the remaining portion of the block structure 43 is exposed from the package 24. For example, the top surface of the package 24 is higher than the top surface of the block structure 43. For example, the top surface of the block structure 43 is recessed from the top surface of the package 24.

[0049] As used herein, the terms "substantially," "generally," "approximately," and "about" are used to indicate and explain small variations. For example, when used in conjunction with a numerical value, the terms may refer to a range of variation of less than or equal to ±10% of the numerical value, for example, less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. As another example, a film or layer having a thickness that is "substantially uniform" may refer to an average thickness of the film or layer having a standard deviation of less than or equal to ±10%, for example, less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. The term "substantially coplanar" may refer to two surfaces that are within 50 μm along the same plane, such as within 40 μm, within 30 μm, within 20 μm, within 10 μm, or within 1 μm along the same plane. If, for example, two components overlap or are within 200 μm, within 150 μm, within 100 μm, within 50 μm, within 40 μm, within 30 μm, within 20 μm, within 10 μm, or within 1 μm of overlap, then the two components may be considered to be "substantially aligned." If the angle between two surfaces or components is, for example, 90°±10°, such as ±5°, ±4°, ±3°, ±2°, ±1°, ±0.5°, ±0.1°, or ±0.05°, then the two surfaces or components may be considered to be "substantially perpendicular." When used in conjunction with an event or circumstance, the terms "substantially", "approximately", "approximately" and "about" may refer to instances where the event or circumstance occurs exactly, as well as instances where the event or circumstance occurs very approximately.

[0050] When describing some embodiments, a component being disposed “on” another component may encompass the case where the former component is directly on (eg, in physical contact with) the latter component as well as the case where one or more intermediate components are positioned between the former and the latter components.

[0051] In addition, amounts, ratios and other numerical values ​​are sometimes presented herein in a range format. It should be understood that such a range format is used for convenience and brevity and should be flexibly construed to include not only the values ​​explicitly specified as the limits of the range, but also all individual values ​​or sub-ranges encompassed within the range, as if each value and sub-range were explicitly specified.

[0052] Although the disclosure has been described and illustrated with reference to specific embodiments of the present invention, these descriptions and illustrations do not limit the disclosure. It is clearly understood by those skilled in the art that various changes may be made, and equivalent elements may be substituted in the embodiments without departing from the true spirit and scope of the disclosure as defined by the appended claims. The illustrations may not necessarily be drawn to scale. Due to variables such as manufacturing processes, there may be differences between the technical reproduction in the disclosure and the actual equipment. There may be other embodiments of the disclosure that are not specifically described. This specification and drawings should be considered illustrative rather than restrictive. Modifications may be made so that specific situations, materials, material compositions, methods or processes are suitable for the goals, spirit and scope of the disclosure. All such modifications are intended to be within the scope of the appended claims. Although the methods disclosed herein have been described with reference to specific operations performed in a specific order, it should be understood that these operations may be combined, subdivided or reordered to form equivalent methods without departing from the teachings of the disclosure. Therefore, unless specifically indicated herein, the order and grouping of operations do not limit the disclosure.

Claims

1. An optical system, comprising: Carrying frame; A light emitter, which is placed on the carrier; an optical receiver, which is mounted on the carrier; a block structure, which is placed on the carrier; as well as A package is placed on the carrier and covers the optical transmitter, the optical receiver and the block structure, wherein the package has a recess above the block structure, and the recess has a cutting surface. 2 . The optical system according to claim 1 , wherein the block structure has a curved surface, and the curved surface is located outside the recess. 3 . The optical system of claim 1 , wherein a portion of the block structure is exposed from the package, and a top surface of the portion of the block structure is lower than a top surface of the package. 4 . The optical system according to claim 3 , wherein the top surface of the portion of the block structure has a middle portion and a peripheral portion, and the middle portion of the top surface is lower than the peripheral portion of the top surface. 5 . The optical system of claim 1 , wherein the package has a top surface and a side surface adjacent to the recess and the top surface of the package, and an angle defined by the side surface of the package and the top surface is not less than 90 degrees. 6 . The optical system according to claim 2 , wherein the curved surface of the block structure comprises a first curved surface convex toward the light emitter or a second curved surface convex toward the light receiver.

7. The optical system according to claim 6, wherein the first curved surface of the curved surface of the block structure is separated from the light emitter by a first distance, and the second curved surface of the curved surface of the block structure is separated from the light receiver by a second distance, and the first distance is greater than the second distance. 8 . The optical system according to claim 1 , wherein the light receiver has a light detection area on a top surface of the light receiver, and the cut surface of the recessed portion of the package is higher than the light detection area of ​​the light receiver.

9. The optical system of claim 1, wherein a width of the recess is smaller than a width of the block structure.

10. The optical system of claim 1, wherein a width of the recess is greater than a width of the block structure.

11. The optical system of claim 1, wherein the block structure is formed of silicon or epoxy.

12. An optical system comprising: Carrying frame; A light emitter, which is placed on the carrier; an optical receiver, which is mounted on the carrier; a block structure disposed between the optical transmitter and the optical receiver; as well as A package is placed on the carrier and covers the light emitter and at least a portion of the block structure, wherein the package has a recess above the block structure, the block structure includes a first portion adjacent to the carrier and a second portion adjacent to the recess, the second portion is located between the recess and the first portion, the second portion has a first curved surface, and the first curved surface includes an arc surface convex toward the top of the light emitter.

13. The optical system of claim 12, wherein a width of the first portion is greater than a width of the second portion. 14 . The optical system according to claim 12 , wherein the second portion has a second curved surface, the second curved surface comprising an arc surface convex toward above the light receiver.

15. The optical system according to claim 12, wherein the second portion of the block structure has a middle portion and a peripheral portion, and the middle portion of the second portion is lower than the peripheral portion of the top surface.

16. An optical system comprising: Carrying frame; A light emitter, which is placed on the carrier; an optical receiver, which is mounted on the carrier; a block structure disposed between the optical transmitter and the optical receiver; as well as package, which contacts the block structure, The package has a curved surface.

17. The optical system of claim 16, wherein the block structure has a recess, and the package and the recess do not overlap in a direction substantially perpendicular to the top surface of the carrier.

18. The optical system of claim 16, wherein the package defines a first opening, the block structure has a second opening, and the first opening connects the second opening.

19. The optical system of claim 18, wherein the package comprises a first portion and a second portion separated from each other by the first opening, and the first opening penetrates the package from a top view. 20 . The optical system of claim 18 , wherein the package has a first sidewall defining the first opening, the block structure has a second sidewall defining the second opening, and the light transmittance of the first sidewall is greater than the light transmittance of the second sidewall.

21. An optical system comprising: Carrying frame; A light emitter, which is placed on the carrier; an optical receiver, which is mounted on the carrier; as well as A package, which is placed on the carrier and covers the optical transmitter and the optical receiver; as well as a target object, which is placed on the carrier, The light detected by the light receiver is reflected by the target object.

22. The optical system according to claim 21, further comprising a block structure disposed between the light emitter and the light receiver, and light reflected at a boundary of the package and air outside the package is blocked by the block structure.

23. The optical system of claim 22, wherein the block structure is disposed across a portion of the optical receiver.

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