Optical device and method of manufacturing the same

Abstract

An optical module and a method of manufacturing an optical module are provided. The optical module includes a carrier, an electronic component, a cover, a diffuser, and a bonding layer. The electronic component is disposed on the carrier. The cover is disposed on the carrier. The cover has a first cavity to house the electronic component. The cover defines a first aperture above the first cavity. The diffuser is disposed within the first aperture. The bonding layer is disposed between the diffuser and a sidewall of the first aperture.

Description

Technical Field

[0001] The present invention relates to an optical device, and more particularly to an optical device comprising a photodetector and a diffuser. Background Technology

[0002] Optical modules (such as ambient light sensors (ALS)) are widely used in various electronic devices, such as cellular phones, tablet computers, and laptops / notebooks. To improve the performance of the photodetector in an optical module, a relatively large detection angle and relatively uniform light are required. However, such structures may inevitably increase the size of the optical module, which will hinder the miniaturization of electronic devices. Summary of the Invention

[0003] According to an aspect of the invention, the optical module includes a carrier, an electronic component, a cover, a diffuser, and a bonding layer. The electronic component is disposed on the carrier. The cover is disposed on the carrier. The cover has a first cavity for receiving the electronic component. The cover defines a first opening above the first cavity. The diffuser is disposed within the first opening. The bonding layer is disposed between the diffuser and a sidewall of the first opening.

[0004] According to another aspect of the invention, the optical module includes a carrier, an electronic component, a cover, a diffuser, and a bonding layer. The electronic component is disposed on the carrier. The cover is disposed on the carrier. The cover defines a first aperture above the electronic component. The diffuser is disposed within the first aperture. The bonding layer is disposed between the diffuser and the sidewall of the first aperture. The bonding layer comprises a material crystallized in a BCC lattice.

[0005] According to another aspect of the invention, the optical module includes a carrier, an electronic component, a cover, and a diffuser. The electronic component is disposed on the carrier. The cover is disposed on the carrier. The cover defines a first opening above the electronic component. The diffuser is disposed within the first opening. The diffuser has an inwardly concave surface.

[0006] According to another aspect of the invention, a method of manufacturing an optical module includes (a) providing a carrier, (b) placing a cap on the carrier, the cap defining an orifice to expose the carrier and a cavity above the orifice, (c) forming an bonding layer on the sidewall of the orifice and the cavity of the cap, (d) dispensing a diffusion gel into the orifice, and (e) removing the carrier from the cap. Attached Figure Description

[0007] Figure 1 Explaining cross-sectional views of an optical device according to some embodiments of the present invention;

[0008] Figure 2A Explaining cross-sectional views of an optical device according to some embodiments of the present invention;

[0009] Figure 2BExplaining cross-sectional views of an optical device according to some embodiments of the present invention;

[0010] Figure 3 Explaining cross-sectional views of an optical device according to some embodiments of the present invention;

[0011] Figure 4A Explaining cross-sectional views of an optical device according to some embodiments of the present invention;

[0012] Figure 4B Description of some embodiments according to the present invention Figure 4A An enlarged view of a portion of the optical equipment in the image;

[0013] Figure 5A Explaining a cross-sectional view of the cover according to some embodiments of the present invention;

[0014] Figure 5B Explaining a cross-sectional view of the cover according to some embodiments of the present invention;

[0015] Figure 6A , Figure 6B , Figure 6C and Figure 6D A method for manufacturing an optical device according to some embodiments of the present invention is described;

[0016] Figure 7A Explaining cross-sectional views of an air-type package according to some embodiments of the present invention; and

[0017] Figure 7B A cross-sectional view illustrating an air-type package according to some embodiments of the present invention is provided.

[0018] Throughout the figures and embodiments, common reference numerals are used to indicate the same or similar components. The invention can be most preferably understood in conjunction with the accompanying drawings and the following embodiments. Detailed Implementation

[0019] Figure 1 Cross-sectional views illustrating some embodiments of an optical device 1 according to a first aspect of the present invention are shown. The optical device 1 includes a carrier 10, electronic components 11a and 11b, a cover 12, and a diffuser 13.

[0020] The carrier 10 may include, for example, a printed circuit board, such as a paper-based copper foil laminate, a composite copper foil laminate, or a polymer-impregnated glass fiber-based copper foil laminate. The carrier 10 may include interconnect structures, such as multiple conductive traces or vias. In some embodiments, the carrier 10 comprises a ceramic material or a metal plate. In some embodiments, the carrier 10 may include a substrate, such as an organic substrate or a lead frame. In some embodiments, the carrier 10 may include a bilayer substrate comprising a core layer and conductive material and / or structures disposed on an upper and lower surface of the carrier 10. The conductive material and / or structures may include multiple traces, pads, or vias.

[0021] Electronic component 11a is disposed on carrier 10. Electronic component 11a may comprise a light-emitting chip or other optical chip. For example, electronic component 11a may comprise a light-emitting diode (LED), a laser diode, or another device that may comprise one or more semiconductor layers. The semiconductor layers may comprise silicon, silicon carbide, gallium nitride, or any other semiconductor material. Electronic component 11a may be connected to carrier 10 by means of, for example, flip-chip or wire bonding technology. In some embodiments, electronic component 11a comprises an LED chip bonded to carrier 10 via a chip bonding material. The LED chip includes at least one wire bonding pad. The LED chip is electrically connected to carrier 10 via a conductive wire, one end of which is bonded to the wire bonding pad of the LED chip, and the other end of which is bonded to the wire bonding pad of carrier 10. Electronic component 11a has an active region (or light-emitting area) facing away from carrier 10.

[0022] Electronic component 11b is disposed on carrier 10 and is physically separate from electronic component 11a. In some embodiments, electronic component 11b may include a photodetector, such as a PIN diode (a diode comprising a p-type semiconductor region, a pure semiconductor region, and an n-type semiconductor region), a photodiode, or a phototransistor. In some embodiments, the second electronic component 11b includes an ambient light sensor (ALS). Electronic component 11b may be connected to carrier 10, for example, by means of flip-chip or wire bonding technology. Electronic component 11b has an active region (or light detection region) facing away from carrier 10.

[0023] A cover (or housing) 12 is disposed on a carrier 10. The cover 12 defines a cavity 12c1 to accommodate electronic component 11a and a cavity 12c2 to accommodate electronic component 11b. The cover 12 has a wall structure 12w disposed between electronic components 11a and 11b to separate them. The cover 12 includes an opaque material to prevent unwanted light emitted by electronic component 11a from directly transmitting to electronic component 11b.

[0024] Cover 12 defines orifices (or openings) 12h1 and 12h2 above cavity 12c1. In some embodiments, orifices 12h1 and 12h2 expose at least a portion (e.g., a light-emitting area) of electronic component 11a. Orifice 12h2 is located above orifice 12h1 (e.g., orifice 12h1 is defined by a portion of cover 12 forming the bottom of orifice 12h2). In some embodiments, the width of orifice 12h2 is greater than the width of orifice 12h1 (e.g., greater than about 10%, greater than about 20%, greater than about 30%, or greater than more than about 30%).

[0025] The cover 12 further defines orifices (or openings) 12h3 and 12h4 above the cavity 12c2. In some embodiments, orifices 12h3 and 12h4 expose at least a portion of the electronic component 11b (e.g., a photodetector region). Orifice 12h4 is located above orifice 12h3 (e.g., orifice 12h3 is defined by a portion of the cover 12 forming the bottom of orifice 12h4), and the orifice is configured to receive a diffuser 13. In some embodiments, the width of orifice 12h4 is greater than the width of orifice 12h3 (e.g., greater than about 10%, greater than about 20%, greater than about 30%, or greater than more than about 30%).

[0026] A diffuser 13 is disposed within an aperture 12h4. The diffuser 13 serves to decompose and uniformly distribute light radiated toward the electronic component 11b, thereby enhancing the uniformity of light received through the electronic component 11b. The cover 12 may be designed to have a relatively large thickness to accommodate the relatively thick diffuser 13, which improves light uniformity. Furthermore, to support the diffuser 13 within the aperture 12h4, a stepped structure is required defining the aperture 12h3, and such a stepped structure further increases the thickness of the cover 12. Moreover, controlling the thickness tolerance of the diffuser 13 (e.g., approximately + / - 30 micrometers) is challenging.

[0027] Figure 2A A cross-sectional view of an optical device 2A according to some embodiments of the present invention is shown. The optical device 2A includes a carrier 20, electronic components 21a and 21b, a cover 22, and a diffusion film 23. Each of the carrier 20 and electronic components 21a and 21b may be similar to or identical to the reference numerals. Figure 1 The carrier 10 and electronic components 11a and 11b are described and illustrated. Alternatively, depending on different design specifications, each of the carrier 20 and electronic components 21a and 21b may differ from... Figure 1 The carrier 10 and electronic components 11a and 11b are shown in the figure.

[0028] A cover (or housing) 22 is disposed on a carrier 20. The cover 22 defines a cavity 22c1 to accommodate electronic component 21a and a cavity 22c2 to accommodate electronic component 21b. The cover 22 has a wall structure 22w disposed between electronic component 21a and electronic component 21b to separate them. The cover 22 includes an opaque material to prevent unwanted light emitted by electronic component 21a from directly transmitting to electronic component 21b.

[0029] Cover 22 defines an aperture (or opening) 22h1 above cavity 22c1. In some embodiments, aperture 22h1 exposes at least a portion (e.g., a light-emitting region) of electronic component 21a. Cover 22 further defines an aperture (or opening) 22h2 above cavity 22c2. In some embodiments, aperture 22h2 exposes at least a portion (e.g., a light-detecting region) of electronic component 21b.

[0030] A diffusion film 23 is disposed within the aperture 22h2. The diffusion film 23 serves to decompose and uniformly distribute light radiated toward the electronic component 21b, thereby enhancing the uniformity of light received by the electronic component 21b. The diffusion film 23 includes a surface 231 facing away from the carrier 20 and a surface 232 facing the carrier 20. The surface 231 of the diffusion film 23 is substantially coplanar with the surface 221 of the cover 22. The surface 232 of the diffusion film 23 is recessed from the surface 222 of the cover 22. For example, the surface 232 of the diffusion film 23 is an inwardly concave surface. For example, the diffusion film 23 may function as a concave lens. In some embodiments, the thickness of the diffusion film 23 is equal to or less than the depth of the aperture 22h2 (or the thickness of the cover 22). For example, the thickness of a portion of the diffusion film 23 adjacent to the sidewall of the aperture 22h2 is substantially equal to the depth of the aperture 22h2. For example, the thickness of a portion of the diffusion film 23 away from the sidewall of the aperture 22h2 is less than the depth of the aperture 22h2.

[0031] In some embodiments, the diffusion film 23 is formed by distributing a diffusion gel within an aperture 22h2 (detailed process described below). In some embodiments, the diffusion film 23 may comprise a frosted glass diffuser, a Teflon diffuser, a holographic diffuser, a milky white glass diffuser, and a gray glass diffuser. In some embodiments, the diffusion film 23 may be formed from GaN or fused silica. The diffusion film 23 may be formed by a distribution technique, such as distributing the diffusion gel within the aperture 22h2. The diffusion gel adhering to the sidewall defining the aperture 22h2 is then cured / hardened to form the diffusion film 23. Therefore, no support structure (e.g., such as...) is required. Figure 1 (as shown in the stepped structure), and the thickness of the cover 22 is reduced. In addition, since the thickness and shape of the diffusion film 23 are generally conformal to the orifice 22h2, the tolerance of the thickness of the diffusion film 23 can be reduced or decreased.

[0032] Figure 2B A cross-sectional view of an optical device 2B according to some embodiments of the present invention is shown. Optical device 2B is similar to optical device 2A except that it further includes a bonding layer 24. The bonding layer 24 is disposed between the diffusion film 23 and the sidewall of the aperture 22h2. The bonding layer 24 is in contact with both the diffusion film 23 and the sidewall of the aperture 22h2. In some embodiments, the thickness of the bonding layer is in the range of 100 nanometers (nm) to 200 nm.

[0033] In some embodiments, the bonding layer 24 has a body-centered cubic (BCC) crystal structure. For example, the bonding layer 24 comprises a material crystallized in a BCC lattice. In some embodiments, the bonding layer may be formed of or comprise a metal or metal oxide. Because the bonding layer 24 comprises a material with a BCC structure, the gaps or distances between two adjacent atoms are relatively large compared to materials with a face-centered cubic (FCC) or simple cubic structure. In other words, the bonding layer 24 may have a loose structure, and the surface fluctuations (or roughness) defined by the stacked atoms of the bonding layer 24 are relatively large. This increases the contact area between the bonding layer 24 and the diffusion film 23 and enhances the bonding ability between the bonding layer 24 and the diffusion film 23, which in turn prevents delamination between the cap 22 and the diffusion film 23.

[0034] Figure 3 A cross-sectional view illustrating an optical device 3 according to some embodiments of the present invention is provided. (Except for...) Figure 3 The orifice 22h2' in the middle is different in shape from Figure 2B Apart from the aperture 22h2, optical device 3 is similar to optical device 2B.

[0035] The orifice 22h2' has a first portion that gradually decreases in size from the surface 221 of the cover 22 toward the surface 222 of the cover 22, and a second portion that gradually decreases in size from the surface 222 of the cover 22 toward the surface 221 of the cover 22. The first portion and the second portion of the orifice 22h2' are connected to define the orifice 22h2'. For example, the orifice 22h2' has the shape of an hourglass or funnel.

[0036] A diffuser 23 is disposed within the aperture 22h2' and is substantially conformal to the shape of the aperture 22h2'. The diffuser 23 serves to decompose and uniformly distribute light radiated toward the electronic component 21b, thereby enhancing the uniformity of light received by the electronic component 21b. The diffuser 23 includes a surface 231 facing away from the carrier 20 and a surface 232 facing the carrier 20. The surface 231 of the diffuser 23 is substantially coplanar with the surface 221 of the cover 22. The surface 232 of the diffuser 23 is recessed from the surface 222 of the cover. For example, the surface 232 of the diffuser 23 is an inwardly concave surface. For example, the diffuser 23 may function as a concave lens. In some embodiments, the thickness of the diffuser 23 is equal to or less than the depth of the aperture 22h2' (or the thickness of the cover 22). For example, the thickness of a portion of the diffuser 23 adjacent to the sidewall of the aperture 22h2' is substantially equal to the depth of the aperture 22h2'. For example, the thickness of a portion of the diffuser on the sidewall furthest from the orifice 22h2' is less than the depth of the orifice 22h2'.

[0037] Figure 4A A cross-sectional view of an optical device 4 according to some embodiments of the present invention is shown. Figure 4A The optical device shown is similar to Figure 2B The optical devices shown are described below, and the differences between them will be described below.

[0038] Cover 42 defines orifices (or openings) 42h1 and 42h2 above cavity 22c1. In some embodiments, orifices 42h1 and 42h2 expose at least a portion (e.g., a light-emitting area) of electronic component 21a. Orifice 42h2 is located above and connected to orifice 42h1. In some embodiments, the width of orifice 42h1 is greater than the width of orifice 42h2 (e.g., greater than about 10%, greater than about 20%, greater than about 30%, or greater than more than about 30%).

[0039] Cover 42 further defines orifices (or openings) 42h3 and 42h4 above cavity 22c2. In some embodiments, orifices 42h3 and 42h4 expose at least a portion of electronic component 21b (e.g., a light detection area). Orifice 42h4 is located above orifice 42h3. In some embodiments, the width of orifice 42h3 is greater than the width of orifice 42h4 (e.g., greater than about 10%, greater than about 20%, greater than about 30%, or greater than more than about 30%).

[0040] A diffusion film 23 is disposed within the orifice 42h4. The diffusion film 23 is used to decompose and uniformly distribute the light radiated toward the electronic component 21b, which will enhance the uniformity of the light received by the electronic component 21b. Figure 4B As shown, the explanation is enclosed by the dashed circle 4A. Figure 4AAn enlarged view of a portion of the optical device 4 shows that the diffusion film 23 includes a surface 231 facing away from the carrier 20 and a surface 232 facing the carrier 20. The surface 231 of the diffusion film 23 is substantially coplanar with the surface 421 of the cover 42. The surface 232 of the diffusion film 23 is recessed from the surface 422 of the cover 42. For example, the surface 232 of the diffusion film 23 is an inwardly concave surface. For example, the diffusion film 23 may function as a concave lens. In some embodiments, the thickness of the diffusion film 23 is equal to or less than the depth of the aperture 42h4. For example, the thickness of a portion of the diffusion film 23 adjacent to the sidewall of the aperture 42h4 is substantially equal to the depth of the aperture 42h4. For example, the thickness of a portion of the diffusion film 23 away from the sidewall of the aperture 42h4 is less than the depth of the aperture 42h4.

[0041] like Figure 4B As shown, orifices 42h3 and 42h4 may define a ladder-like structure. In some embodiments, the ladder-like structure has arcuate corners (circled by the dashed circle 4B). The diffusion membrane 23 is conformally shaped to the orifice 42h4 of the cap 42, and the ladder-like structure of the cap 42 is used to prevent the diffusion gel from overflowing or seeping out during the manufacturing process.

[0042] Figure 5A and Figure 5B Cross-sectional views illustrating caps 52A and 52B, and diffusion films 53A and 53B according to some embodiments of the present invention are shown. Figure 5A As shown, the diffusion membrane 53A can be placed using the two openings of the cover 52A. Figure 5B As shown, the cover 53B may include three openings to define two trapezoidal structures. In some embodiments, the cover may include any number of trapezoidal structures, depending on different design requirements.

[0043] Figure 6A , Figure 6B , Figure 6C and Figure 6D This is a cross-sectional view of an optical device manufactured at various stages according to some embodiments of the present invention. Several figures have been simplified for a preferred understanding of aspects of the invention.

[0044] refer to Figure 6A A carrier 60 is provided, and a cover 62 is placed on the carrier 60. In some embodiments, the cover 62 is attached to the carrier 60 via an adhesive layer, such as tape or glue. The cover 62 includes openings 62h1 and 62h2 to expose a portion of the carrier 60. The cover 62 further includes cavities 62c1 and 62c2 above the openings 62h1 and 62h2 to accommodate electronic components. For example, cavity 62c1 may be used to accommodate a light emitter, and cavity 62c2 may be used to accommodate a photodetector. In some embodiments, the widths of cavities 62c1 and 62c2 are greater than the widths of openings 62h1 and 62h2.

[0045] refer to Figure 6B The bonding layer 64 is formed on the sidewall of the aperture 62h2 by, for example, sputtering or any other suitable process. In other embodiments, depending on different design requirements, the bonding layer 64 may also be formed on the sidewall of the cavity 62c2. In some embodiments, the bonding layer 64 has a BCC crystal structure. For example, the bonding layer 64 contains a material crystallized in a BCC lattice. In some embodiments, the bonding layer may be formed of or contain a metal or metal oxide. Because the bonding layer 64 contains a material with a BCC structure, the gap or distance between two adjacent atoms is relatively larger than that of a material with an FCC or simple cubic structure. In other words, the bonding layer 64 may have a loose structure, and the surface fluctuations (or roughness) defined by the stacked atoms of the bonding layer 64 are relatively large. This increases the contact area between the bonding layer 64 and the diffusion film 63 and enhances the bonding ability between the bonding layer 64 and the diffusion film 63, which in turn prevents delamination between the cap 62 and the diffusion film 63.

[0046] refer to Figure 6C The diffusion gel 63' is dispensed into the orifice 62h2. In some embodiments, the diffusion gel 63' may comprise GaN or fused silica. In some embodiments, the amount of diffusion gel 63' is controlled to prevent seepage or flow from the orifice 62h2. For example, the amount of diffusion gel 63' is controlled to prevent it from flowing onto the bottom surface 62a of the cavity 62c2. For example, the diffusion gel 63' is substantially below or coplanar with the bottom surface 62a of the cavity 62c2.

[0047] refer to Figure 6D The diffusion gel 63' is then cured (heated or hardened) to attach or bond to the bonding layer 64, thereby forming a diffusion film 63. In some embodiments, the diffusion gel 63' is cured by, for example, but not limited to, an oven or other suitable equipment to form the diffusion film 63. After the curing operation, the diffusion film 63 has a recessed surface (or an inwardly concave surface) 63r.

[0048] Still referencing Figure 6D Remove the carrier 60 and adhesive (if present) from the cover 62 and the diffusion film 63. The cover 62 with the diffusion film 63 can be placed on the carrier having a light emitter and a photodetector to form a shape such as Figure 2B The optical device shown.

[0049] In some embodiments, Figure 6A , Figure 6B , Figure 6C and Figure 6D The operations shown are applicable to forming an air-type package with a lens. For example, as... Figure 7AAs shown, in a comparative method for forming an air-type package 7A, glass 70 is placed on a cover 71 having an aperture 71h and covers the aperture 71h of the cover 71 to act as a lens. However, placing glass 70 on the cover 71 increases the thickness of the air-type package 7A. Figure 7B As shown, the lens 72 is formed within the aperture 71h of the cover 71 by dispensing transparent epoxy resin into the aperture 71h, which reduces the thickness of the air-type package 7B.

[0050] As used herein, the terms “substantially,” “largely,” “approximately,” and “about” are used to indicate and describe minor variations. For example, when used in conjunction with numerical values, these terms may refer to a range of variation less than or equal to ±10% of that value, such as 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, “substantially uniform” for the thickness of a film or layer may refer to the standard deviation of the average thickness of the film or layer being less than or equal to ±10% (e.g., 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" can refer to two surfaces that are within 50 μm along the same plane (e.g., within 40 μm, 30 μm, 20 μm, 10 μm, or 1 μm along the same plane). If, for example, two components overlap or overlap within 200 μm, 150 μm, 100 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, or 1 μm, then the two components can be considered "substantially aligned." If the angle between two surfaces or components is, for example, 90° ± 10° (e.g., ±5°, ±4°, ±3°, ±2°, ±1°, ±0.5°, ±0.1°, or ±0.05°), then the two surfaces or components can be considered "substantially perpendicular." When used in conjunction with an event or situation, the terms "substantially," "substantially," "approximately," and "about" can refer to the exact occurrence of the event or situation as well as the very close approximation of its occurrence.

[0051] In the description of some embodiments, the term "on another component" can cover situations where the preceding component is directly on the following component (e.g., in physical contact with the following component), and situations where one or more intermediate components are located between the preceding and following components.

[0052] Additionally, quantities, ratios, and other values ​​are sometimes presented in range format in this document. It is understood that this range format is for convenience and brevity and should be flexibly interpreted as including not only values ​​explicitly specified as range limits, but also all individual values ​​or subranges covered within the range, as if each value and subrange were explicitly specified.

[0053] Although the invention has been described and illustrated with reference to specific embodiments thereof, such description and illustration are not limiting of the invention. It will be readily understood by those skilled in the art that various changes can be made and equivalent elements can be substituted within the embodiments without departing from the true spirit and scope of the invention as defined by the appended claims. Illustrations need not be drawn to scale. Differences may exist between artistic representations of the invention and actual devices due to variations in the class of manufacturing processes. Other embodiments of the invention may exist that are not specifically described. This specification and the drawings should be considered illustrative rather than restrictive. Modifications may be made to adapt particular circumstances, materials, compositions, methods, or processes to the objectives, spirit, and scope of the invention. All such modifications are intended to be within the scope of the claims appended herein. Although the methods disclosed herein have been described with reference to specific operations performed in a particular order, it will be understood that these operations may be combined, subdivided, or rearranged to form equivalent methods without departing from the teachings of the invention. Therefore, unless specifically indicated herein, the order and grouping of operations are not a limitation of the invention.

Claims

1. An optical module comprising: carrier; A photodetector and a photoemitter are mounted on the carrier; The cover is placed on the carrier; and A diffuser disposed within the cover, wherein the diffuser has an inward concave surface toward the photodetector, the diffuser has an upper surface relative to the inward concave surface, the inward concave surface having a central region and a peripheral region surrounding the central region, and the distance between the upper surface and the central region of the inward concave surface is less than the distance between the upper surface and the peripheral region of the inward concave surface. and A bonding layer, wherein the cover defines a first aperture above the photodetector, the bonding layer is disposed between the diffuser and the sidewall of the first aperture, and the minimum thickness of the diffuser is less than the thickness of the bonding layer.

2. The optical module of claim 1, wherein the cover defines a second opening above the light emitter, the diffuser is disposed within the first opening, and the second opening exposes the light-emitting area of ​​the light emitter.

3. The optical module of claim 2, wherein the inward concave surface of the diffuser is recessed from the surface of the bonding layer.

4. The optical module of claim 3, wherein the cover has a first cavity for receiving the photodetector, the surface of the bonding layer is exposed from the first cavity, and the lower surface of the bonding layer overlaps with the photodetector in the vertical direction.

5. The optical module of claim 4, wherein the cover has a second cavity for receiving the light emitter, and the second cavity communicates with the outside of the optical module through the second aperture.

6. The optical module of claim 3, wherein the diffuser has an hourglass shape, the bonding layer contacts the sidewall of the diffuser having the hourglass shape and the first aperture, and the bonding layer is conformal to the sidewall of the diffuser having the hourglass shape.

7. The optical module of claim 6, wherein the diffuser is conformal to the sidewall of the first aperture and does not contact the second aperture.

8. The optical module of claim 2, wherein the cover has a first cavity for receiving the photodetector, the cover further defining a third opening between the first opening and the first cavity, the width of the first opening being less than the width of the third opening, and the width of the third opening being less than the width of the first cavity.

9. An optical module comprising: carrier; A photodetector and a photoemitter are mounted on the carrier; The cover is placed on the carrier; and A diffuser is disposed within the cover, wherein the diffuser has an inwardly concave surface facing the photodetector, the inwardly concave surface of the diffuser having a first region near the geometric center of the diffuser and a second region away from the geometric center of the diffuser, the first region being spaced apart from the photodetector by a first distance along a direction perpendicular to the light-receiving surface of the photodetector, the second region being spaced apart from the photodetector by a second distance along the same direction, the first distance being greater than the second distance. The cover has a first cavity for accommodating the photodetector, the cover defines a first opening above the photodetector and a second opening located between the first opening and the first cavity, the width of the first opening being less than the width of the second opening, the width of the second opening being less than the width of the first cavity, the first opening and the second opening defining a stepped structure, the diffuser being disposed within the first opening, and the thickness of the portion of the diffuser adjacent to the sidewall of the first opening being equal to the depth of the first opening.

10. The optical module of claim 9, further comprising a bonding layer disposed between the diffuser and the sidewall of the first aperture, wherein the surface of the bonding layer is exposed from the second aperture.

11. The optical module of claim 10, wherein the bonding layer has a body-centered cubic (BCC) crystal structure.

12. The optical module according to claim 10, wherein the stepped structure has an arc-shaped corner.

13. The optical module of claim 12, wherein the arcuate corner protrudes from the surface of the bonding layer and is exposed from the first cavity.

14. The optical module of claim 12, wherein the arcuate corner protrudes from the surface of the bonding layer and is exposed from the second aperture.

15. The optical module of claim 10, wherein the minimum thickness of the diffuser is less than the thickness of the bonding layer.

16. The optical module of claim 9, wherein the first aperture has a first opening that gradually decreases in size from the cover toward the carrier and a second opening that gradually decreases in size from the carrier toward the cover, and wherein the first opening is connected to the second opening.

17. The optical module of claim 9, wherein the cover has a second cavity for accommodating the light emitter, the cover defining a third opening above the light emitter and a fourth opening located between the third opening and the second cavity, the width of the third opening being less than the width of the fourth opening, the width of the fourth opening being less than the width of the second cavity.

18. A method for manufacturing an optical module, the method comprising: (a) Provide a carrier; (b) Place a cover on the carrier, the cover defining an opening to expose the carrier and the cavity above the opening; (c) A bonding layer is formed on the sidewall of the orifice; (d) Dispensing the diffusion gel into the orifice, comprising: controlling the amount of the diffusion gel to prevent the diffusion gel from flowing onto the bottom surface of the cavity, such that the horizontal plane of the diffusion gel is equal to or lower than the bottom surface of the cavity; (d-1) The diffusion gel is cured to form a diffuser having an inwardly concave surface, wherein the bonding layer is disposed between the diffuser and the sidewall of the orifice, and the minimum thickness of the diffuser is less than the thickness of the bonding layer; (e-1) Flip the cover; and (e-2) The cover is placed on a substrate on which a photodetector is placed, wherein the photodetector is housed in the cavity, wherein the inward concave surface of the diffuser faces the photodetector, the inward concave surface of the diffuser has a first region near the geometric center of the diffuser and a second region away from the geometric center of the diffuser, the first region being spaced apart from the photodetector by a first distance along a direction perpendicular to the light-receiving surface of the photodetector, the second region being spaced apart from the photodetector by a second distance along the direction, the first distance being greater than the second distance.

19. The method of claim 18, wherein in operation (d-1), the inward concave surface of the diffuser is recessed from the surface of the bonding layer.

20. The method of claim 19, wherein the bonding layer has a body-centered cubic (BCC) crystal structure and the surface of the bonding layer is exposed from the cavity.

21. The method of claim 18, wherein after operation (d-1), it further comprises: (e) Remove the carrier from the cover.

22. The method of claim 18, wherein the width of the cavity is greater than the width of the orifice.

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