Design and method for integrating a distributable light-transmitting aperture in a thin-type optical sensor module

Abstract

Embodiments of the present disclosure relate to a design and method for integrating a distributable light-transmissive aperture in a thin light sensor module. A method of manufacturing a light sensor module includes: connecting a light sensing circuit to an interconnect on a substrate, and forming a cap. The cap is formed by: making a cap substrate from a light-opaque material to form an opening therein; placing the top surface of the cap substrate face down; dispensing a light-transmissive material into the opening; using a thermal tool to compress the light-transmissive material such that the light-transmissive material fully flows into the opening to form a light-transmissive aperture; and placing the cap substrate in a curing environment. A bonding material is dispensed onto the substrate. The cap is picked up and placed on the substrate, and the substrate is positioned such that the light-transmissive aperture is aligned with the light sensing circuit, wherein the bonding material bonds the cap to the substrate to form a light sensor module.

Description

Technical Field

[0001] The present disclosure relates to a cap design for a thin optical sensor module, and more particularly to a method of forming a light-transmissive aperture in a cap in such a way that the cap has an upper wall that is thinner than prior art designs, thereby enabling the production of a thin optical sensor module. Background Art

[0002] Mobile electronic devices, such as smart phones, tablet computers, earbuds, headphones, headsets, and smart watches, typically employ one or more optical sensor modules. For example, a smart phone may employ an optical sensor module to detect the proximity of a user's ear, so as to know to turn off its touch screen when the user makes a voice call, thereby ensuring that the user's ear does not provide inadvertent input to the touch screen. As another example, a smart phone may have a camera system that employs an optical sensor module to detect ambient lighting conditions to adjust the camera settings when the user takes a picture to produce a better image.

[0003] Such an optical sensor module is typically formed by placing passive and / or active light sensing components on a substrate, and then bonding a cap over the light sensing components to thereby protect the light sensing components from damage. The cap includes a light-transmissive closing aperture, such as a lens, located over the components.

[0004] Typically, the cap is formed with an opening defined therein, and the light-transmissive aperture is installed in the opening, and typically such light-transmissive aperture installation is performed by injection molding. While this does successfully produce the desired cap with a light-transmissive aperture securely positioned therein, the use of injection molding limits the shapes that can be formed. Additionally, injection molding typically cannot produce a light-transmissive aperture having a thickness less than 150 μm, and there are typically limitations if the light-transmissive aperture is formed of glass.

[0005] The current commercial need is for optical sensor modules with reduced thickness (e.g., on the order of 0.4 mm to 0.8 mm). However, conventional processes cannot produce a cap that is thin enough for an optical sensor to enable the production of the desired optical sensor module. Accordingly, further development of cap designs and light-transmissive aperture production is needed. Summary of the Invention

[0006] Disclosed herein is a method of forming a cap for an optical sensor module. The method includes: manufacturing a cap substrate from a light-opaque material to form at least one opening therein; placing the cap substrate face down in a production environment; dispensing a light-transmissive material into the at least one opening; using a thermal tool to compress the light-transmissive material so that the light-transmissive material fully flows into the at least one opening to thereby form at least one light-transmissive aperture; and placing the cap substrate in a curing environment to thereby fabricate a cap for an optical sensor module.

[0007] The cap base can be manufactured using injection molding.

[0008] Placing the cap base face - down in a manufacturing environment can include: placing the top face of the cap base down on the top face of a tape; and placing the bottom face of the tape down in the manufacturing environment.

[0009] The light - transmissive material can be dispensed through a needle into at least one opening.

[0010] The cap base can be manufactured such that the sidewall defines at least one opening, the sidewall has at least one ridge extending therefrom, and using a hot tool to compress the light - transmissive material can be used to cause the light - transmissive material to flow around at least one ridge.

[0011] The cap base can be manufactured to have an overflow region into which excess light - transmissive material can flow when the light - transmissive material is compressed using a hot tool.

[0012] The method can also include removing the hot tool from the light - transmissive material before placing the cap base into a curing environment.

[0013] The method can also include removing the hot tool from the light - transmissive material after placing the cap base into a curing environment.

[0014] Placing the cap base into a curing environment can include placing the cap base into an oven.

[0015] Placing the cap base into a curing environment can include irradiating the light - transmissive material with curing light.

[0016] Using a hot tool to compress the light - transmissive material can be used to form the bottom surface of the light - transmissive material with a desired shape.

[0017] Placing the cap base face - down in a manufacturing environment can include placing the cap base face - down into a fixture having a top surface facing the cap top surface.

[0018] The top surface of the fixture can be shaped such that using a hot tool to compress the light - transmissive material shapes the top surface of the light - transmissive material to have a shape opposite to the shape of the top surface of the fixture.

[0019] The present disclosure also discloses a method of manufacturing a light sensor module, including: connecting at least one light sensing circuit to an interconnect on a substrate; and forming a cap. The cap is formed by: manufacturing a cap substrate from a light-opaque material to form at least one opening therein; placing the top surface of the cap substrate face down in a manufacturing environment; dispensing a light-transmissive material into at least one opening; using a heat tool to compress the light-transmissive material such that the light-transmissive material fully flows into at least one opening to form at least one light-transmissive aperture; and placing the cap substrate in a curing environment to manufacture the cap. The method may further include: dispensing a bonding material onto the substrate; and picking up the cap and placing the cap on the substrate, the substrate being positioned such that at least one light-transmissive aperture is aligned with at least one light sensing circuit, wherein the bonding material bonds the cap to the substrate to form a light sensor module.

[0020] Connecting at least one light sensing circuit to the interconnect may include connecting a passive light sensing circuit to the interconnect.

[0021] Connecting at least one light sensing circuit to the interconnect may include connecting an active light sensing circuit to the interconnect.

[0022] The cap substrate may be manufactured using injection molding.

[0023] Placing the cap substrate face down in the manufacturing environment may include: placing the top surface of the cap substrate face down on the top surface of a tape; and placing the bottom surface of the tape face down in the manufacturing environment.

[0024] The light-transmissive material may be dispensed into at least one opening through a needle.

[0025] The cap substrate may be manufactured such that a sidewall defines at least one opening, the sidewall having at least one ridge extending therefrom, and using a heat tool to compress the light-transmissive material may be used to cause the light-transmissive material to flow around at least one ridge.

[0026] The cap substrate may be manufactured to have an overflow region into which excess light-transmissive material may flow when the light-transmissive material is compressed using a heat tool.

[0027] The method may further include removing the heat tool from the light-transmissive material before placing the cap substrate in the curing environment.

[0028] The method may further include removing the heat tool from the light-transmissive material after placing the cap substrate in the curing environment.

[0029] Placing the cap substrate in the curing environment may include placing the cap substrate in an oven.

[0030] Placing the cap substrate in the curing environment may include irradiating the light-transmissive material with curing light.

[0031] Using a hot tool to compress a light-transmissive material can be used to form the bottom surface of the light-transmissive material into a desired shape.

[0032] Placing the cap substrate top surface down in a manufacturing environment can include placing the cap substrate top surface down into a fixture having a top surface facing the cap top surface.

[0033] The top surface of the fixture can be shaped such that using a hot tool to compress the light-transmissive material serves to form the top surface of the light-transmissive material into a shape opposite to the shape of the top surface of the fixture.

[0034] Also disclosed herein is a cap for a light sensor. The cap includes: a top wall; a side wall that extends generally perpendicularly from the top wall and extends around the top wall; and a dividing side wall that extends from a portion of the side wall to another portion of the side wall, thereby defining a first cavity and a second cavity. The first cavity includes a central through-hole extending through the top wall and at least one release blind hole that extends into but not through the top wall. The at least one release blind hole docks with the central through-hole to be in fluid communication therewith.

[0035] The central through-hole can be defined by an inner side wall extending through the top wall, and a ridge can extend outwardly from the inner side wall.

[0036] A light-transmissive aperture can be mounted within the central through-hole, wherein the light-transmissive aperture has a cavity defined in its outer side wall to dock with the ridge of the inner side wall, thereby mechanically anchoring the light-transmissive aperture within the central through-hole.

[0037] The central through-hole can be circular and the at least one release blind hole is semi-circular. Brief Description of the Drawings

[0038] Figure 1 is a perspective view of the bottom surface of the cap described herein, wherein the light-transmissive aperture is formed using the process described herein.

[0039] Figure 2 is Figure 1 a cross-sectional view of the cap, wherein the cap is arranged such that its top surface is up.

[0040] Figure 3 is a schematic view of a cap substrate placed in a manufacturing environment in a "dead bug" position on Kapton tape (which forms the cap once the light-transmissive aperture is formed) Figure 1 of.

[0041] Figure 4 is Figure 3 a schematic view of the cap substrate after the light-transmissive material has been dispensed into the opening of the cap substrate.

[0042] Figure 5 is Figure 4Schematic of the cap base, showing the application of a hot tool to the dispensed light-transmissive material to compress the material.

[0043] Figure 6 is Figure 5 Schematic of the cap base, showing how the hot tool compresses the dispensed light-transmissive material and showing the cap base ready for curing.

[0044] Figure 7 is Figure 5 the cap base after curing with the tape removed, thereby forming Figure 1 a schematic of the cap.

[0045] Figure 8 is a perspective view of the bottom surface of the cap described, having the formed and shown light-transmissive aperture.

[0046] Figure 9 is a perspective view of the top surface of the cap described herein.

[0047] Figure 10 is a perspective view of the top surface of the light sensor base, having a light sensing assembly mounted thereon but without the cap formed thereon herein.

[0048] Figure 11 is Figure 10 a perspective view of the light sensing base after the cap has been joined in place, thereby forming the light sensing module described herein. Detailed Description

[0049] The following disclosure enables those skilled in the art to make and use the subject matter disclosed herein. Without departing from the spirit and scope of the present disclosure, the general principles described herein can be applied to embodiments and applications other than those detailed above. The present disclosure is not intended to be limited to the embodiments shown, but rather to the broadest scope consistent with the principles and features disclosed or suggested herein.

[0050] A method of manufacturing a cap for a light sensor for a consumer electronic product is now described, the cap having a light-transmissive aperture formed therein, where "light-transmissive aperture" refers to a physical structure through which light or certain bandwidths of light can pass but physical objects cannot. Initially, a plurality of such caps are formed, for example, using injection molding, each having a defined opening therein. These caps are placed on a tape (e.g., Kapton) such that the tape is attached to the top side of the cap, and the resulting tape is loaded onto a reel.

[0051] Now referring to Figure 1The structure of each cap 22 is described herein. The cap 22 here is opaque to light and is shown with its bottom surface facing up and its top surface facing down. The cap 22 has a front wall 31 and side walls 32 extending therefrom, and a dividing side wall 33 extending from the front wall, thereby defining two chambers 34 and 36 each having openings 24 and 26 extending through the front wall. The opening 24 includes a main circular opening 24a, having two semi-circular openings 24b and 24c adjacent thereto; similarly, the opening 26 includes a main circular opening 26a, having two semi-circular openings 26b and 26c adjacent thereto. Note that the main circular opening 24a is a through-hole, while the openings 24b and 24c are blind holes (meaning they do not extend completely through the front wall 31 of the cap 22); similarly, the main circular opening 26a is a through-hole, while the openings 26b and 26c are blind holes.

[0052] Figure 2 Shown is a cross-sectional view of the cap 22 with its top surface facing up. As can be seen from the cross-section, the main circular opening 24a of the opening 24 is formed by a side wall 51, the side wall 51 having a ridge 53 extending outwardly towards the center of the main circular opening 24a; similarly, the main circular opening 26a of the opening 26 is formed by a side wall 55, the side wall 55 having a ridge 57 extending outwardly towards the center of the main circular opening 26a. Note that the semi-circular openings 24b, 24c and 26b, 26c lack this feature and are instead defined by smooth, straight side walls and the bottom surface of the top side of the cap 22. The ridges 53 and 57 may extend around the entire side walls 51 and 55 of the main circular openings 24a and 26a, or alternatively may extend partially around the side walls 51 and 55 of the main circular openings 24a and 26a such that portions of those side walls 51 and 55 are smooth and straight. In some cases, features (e.g., valve structures) may be formed in the cap 22 to allow internal air to escape in the case where the internal air expands due to a temperature increase. Although the openings 24 and 26 are shown as circular, they may also be of other shapes, such as oval, square, rectangular, etc.

[0053] For the remainder of this specification, first referring to Figure 3 , for clarity, the formation of a cap structure 22 will be described. To form the aperture, a portion of the tape 20 extends from the reel 19 and is placed such that the bottom surface of the tape 20 faces down, and thus the bottom side of the cap structure 22 faces up and is in the "dead bug" position.

[0054] Then, the light-transmissive materials 25 and 27 are dispensed from the needles or nozzles of an automatic dispensing device into the openings 24 and 26 defined in the cap structure 22 as shown in Figure 4 . As described above, the light-transmissive material 25 may be completely light-transmissive, or may be tuned to transmit certain wavelengths of light while attenuating other wavelengths of light. It is expected that the light-transmissive materials 25 and 27 will remain within the main circular openings 24a and 26a of the openings 24 and 26 at this step.

[0055] As for the light-transmissive material itself, it can be completely transparent to light or can act as a band-pass filter, allowing only light in certain frequency bands (e.g., infrared) to pass through. In some cases, the light-transmissive material can alternatively act as a low-pass filter or a high-pass filter to filter out light above or below a specific frequency. For example, the light-transmissive material can be a material based on silicon, epoxy resin, or acrylic.

[0056] Thereafter, as Figure 5 shown, hot tools 30 and 32 having shapes substantially equal to the inner diameters of openings 24 and 26 are respectively placed in openings 24 and 26 and pressed onto light-transmissive materials 25 and 27, and then removed. This causes the bottom surfaces of light-transmissive materials 25 and 27 to be pressed into shapes corresponding to the surface shapes of hot tools 30 and 32 facing light-transmissive materials 25 and 27, where the excess light-transmissive material flows into semi-circular openings 24b, 24c and 26b, 26c. Here, it should be noted that when pressed by hot tools 30 and 32, the molten light-transmissive material will flow completely around ridges 53 and 57 of main circular openings 24a and 26a of openings 24 and 26. When cured, these ridges 53 and 57 mechanically anchor light-transmissive materials 25 and 27 firmly in place.

[0057] The surfaces of hot tools 30 and 32 facing light-transmissive materials 25 and 27 can be convex in shape to form the bottom surfaces of light-transmissive materials 25 and 27 into concave shapes; conversely, the surfaces of hot tools 30 and 32 facing light-transmissive materials 25 and 27 can be concave in shape to form the bottom surfaces of light-transmissive materials 25 and 27 into convex shapes. As an alternative, the surfaces of hot tools 30 and 32 facing the light-transmissive material can be flat in shape to form flat bottom surfaces of the light-transmissive material.

[0058] Depending on the temperatures of hot tools 30 and 32, this action can also perform pre-curing of light-transmissive materials 25 and 27. Then, when cap structure 22 is still attached to tape 20, cap structure 22 is placed in a curing environment (e.g., an oven applying heat, or in the presence of curing light) to fully cure transmissive materials 25 and 27 so that they become light-transmissive apertures 25a and 27a as Figure 6 shown. As Figure 7 shown, cap structure 22 is then removed from tape 20.

[0059] As an alternative to removing hot tools 30 and 32 before curing, hot tools 30 and 32 can alternatively remain in place during curing and then be removed before removing tape 20.

[0060] As an alternative to dispensing and then curing the single layers of light-transmissive materials 25 and 27, multiple layers can be dispensed and cured, where the process sequence is to dispense a layer, thermally press the layer using a heat tool, and cure the layer, thermally press the next layer, cure the next layer, etc. before proceeding to dispense the next layer.

[0061] As Figure 8 shown is the bottom surface of the cap 22, where it can be seen that the light-transmissive apertures 25a and 27a have been installed within the openings 24 and 26 (where the top surfaces of the light-transmissive apertures 25a and 27a are represented by the dashed lines shown), and the excess material has properly flowed from the main circular openings 24a and 26a into the semi-circular openings 24b, 24c and 26b, 26c.

[0062] The top surface of the cap 22 is shown in Figure 9 wherein it can also be observed that the light-transmissive apertures 25a and 27a installed within the openings 24 and 26.

[0063] After the tape 20 is removed, the cap 22 is picked up and placed on a light sensor unit that contains passive and / or active components. A sample light sensing unit 39 is shown in Figure 10 The light sensing unit 39 is an active proximity sensor that includes a substrate 40 having a light source (e.g., infrared) 50 and a light sensor (e.g., infrared) 44. The light source 50 is connected to a wiring layer on or within the substrate 40 via a lead 54 connected to a pad 52, and the light sensor 44 is connected to a wiring layer on or within the substrate 40 via a lead 48 connected to a pad 46. To sense the proximity of an object, the light sensor 44 detects the photons received from the light source 50, and a sufficient level of the detected photons can be inferred to mean that an object is nearby. An adhesive layer 42 is dispensed onto the surface of the substrate 40, and once the cap 22 is placed onto the substrate 40, above the light source 50 and the light sensor 44, the cap 22 is bonded to the substrate 40.

[0064] The completed light sensor module 19 can be seen in Figure 11 It should be understood that any suitable components can be on the substrate 40 within the light sensor module 19, such as to fabricate proximity sensors, ambient light sensors, time-of-flight ranging sensors, etc.

[0065] As an alternative to the above steps starting with the cap 22 over the length of the tape, the cap 22 can alternatively be placed in a metal carrier and the above steps can be carried out. In the case of using a metal carrier, the metal carrier can be shaped to affect the shape of the formed light-transmissive apertures 25a and 27a. For example, the metal carrier can be shaped to form the top surfaces of the light-transmissive apertures 25a and 27a into a convex or concave shape, or can be shaped such that the top surfaces of the light-transmissive apertures 25a and 27a are higher or lower than the top surface of the cap 22. As another alternative, the cap 22 can be placed in a "live bug" position with its inner surface (bottom surface) sealed. The light-transmissive materials 25 and 27 can be dispensed from the top sides of the openings 24 and 26 defined in the cap 22. When a controlled volume of the material is dispensed, its surface tension is then cured into the designed shape, such as the designed convex shape, without the need to use a heat tool.

[0066] The advantages of the above design and forming process are manifold. The light-transmissive apertures 25a and 27a formed using the above forming process greatly reduce the thickness of the top wall of the cap 22 to, for example, as low as 70 μm to 80 μm or even lower. By reducing the thickness of the top wall of the cap 22 while still maintaining an internal space for the internal passive and / or active components, the thickness of the light sensor module 19 itself can be reduced to below 0.8 mm, thereby allowing for the manufacture of thinner consumer electronic devices using the light sensor module 19 or freeing up additional space inside the consumer electronic devices using the light sensor module 19. Additionally, by using a light-transmissive dispensable material instead of glass or injection molding material to form the light-transmissive apertures 25a and 27a, a wider range of material choices is provided. Additionally, since mounting glass into the cap can be expensive and since injection molding generates a large amount of waste, while the above molding process does not, the manufacturing cost can be reduced. Further still, the use of the above forming process allows for the manufacture of light-transmissive apertures and having shapes that are not easily or inexpensively achievable using glass or injection molding.

[0067] Although the present disclosure has been described with respect to a limited number of embodiments, those skilled in the art who benefit from the present disclosure will understand that other embodiments can be envisioned without departing from the scope of the present disclosure as disclosed herein. Therefore, the scope of the present disclosure should be limited only by the appended claims.

Claims

1. A method of forming a cap for an optical sensor module, the method comprising: manufacturing a cap substrate from a light-opaque material to form at least one opening in the cap substrate; placing the cap substrate face-down in a manufacturing environment; dispensing a light-transmissive material into the at least one opening; using a heat tool to compress the light-transmissive material so that the light-transmissive material fully flows into the at least one opening to form at least one light-transmissive aperture; and placing the cap substrate in a curing environment to manufacture the cap for the optical sensor module; wherein the cap substrate is manufactured such that sidewalls define the at least one opening, and the sidewalls have at least one ridge extending from the sidewalls; and wherein using the heat tool to compress the light-transmissive material causes the light-transmissive material to flow around the at least one ridge.

2. The method according to claim 1, wherein injection molding is used to manufacture the cap substrate.

3. The method according to claim 1, wherein placing the cap substrate face-down in the manufacturing environment comprises: placing the cap substrate face-down on the top surface of a tape; and placing the tape face-down in the manufacturing environment.

4. The method according to claim 1, wherein the light-transmissive material is dispensed into the at least one opening through a needle.

5. The method according to claim 1, wherein the cap substrate is manufactured to have an overflow region into which excess light-transmissive material can flow when the light-transmissive material is compressed using the heat tool.

6. The method according to claim 1, further comprising removing the heat tool from the light-transmissive material before placing the cap substrate in the curing environment.

7. The method according to claim 1, further comprising removing the heat tool from the light-transmissive material after placing the cap substrate in the curing environment.

8. The method according to claim 1, wherein placing the cap substrate in a curing environment comprises placing the cap substrate in an oven.

9. The method according to claim 1, wherein placing the cap substrate in a curing environment comprises irradiating the light-transmissive material with curing light.

10. The method according to claim 1, wherein using the heat tool to compress the light-transmissive material is for shaping the bottom surface of the light-transmissive material to have a desired shape.

11. The method according to claim 1, wherein placing the cap substrate face-down in the manufacturing environment comprises: placing the cap substrate face-down in a fixture having a top surface facing the top surface of the cap.

12. The method according to claim 11, wherein the top surface of the fixture is shaped such that using the heat tool to compress the light-transmissive material is for shaping the top surface of the light-transmissive material to have a shape opposite to the shape of the top surface of the fixture.

13. A method of fabricating an optical sensor module, the method comprising: connecting at least one light-sensing circuit to an interconnect on a substrate; forming a cap by the following steps: Manufacture a cap substrate from a light-opaque material to form at least one opening in the cap substrate; Place the top surface of the cap substrate face down in a manufacturing environment; Dispense a light-transmissive material into the at least one opening; Use a heat tool to compress the light-transmissive material so that the light-transmissive material fully flows into the at least one opening to form at least one light-transmissive aperture; And Place the cap substrate in a curing environment to manufacture the cap; Dispense a bonding material onto the substrate; Pick up the cap and place the cap on the substrate, the substrate being positioned such that the at least one light-transmissive aperture is aligned with the at least one light-sensing circuit, wherein the bonding material bonds the cap to the substrate to form the light sensor module; Wherein the cap substrate is manufactured such that sidewalls define the at least one opening, the sidewalls having at least one ridge extending from the sidewalls; And Wherein the heat tool is used to compress the light-transmissive material to cause the light-transmissive material to flow around the at least one ridge.

14. The method according to claim 13, wherein connecting the at least one light-sensing circuit to the interconnect includes connecting a passive light-sensing circuit to the interconnect.

15. The method according to claim 13, wherein connecting the at least one light-sensing circuit to the interconnect includes connecting an active light-sensing circuit to the interconnect.

16. The method according to claim 13, wherein injection molding is used to manufacture the cap substrate.

17. The method according to claim 13, wherein placing the cap substrate face down in the manufacturing environment includes: Place the top surface of the cap substrate face down on the top surface of a tape; And Place the tape face down in the manufacturing environment.

18. The method according to claim 13, wherein the light-transmissive material is dispensed into the at least one opening through a needle.

19. The method according to claim 13, wherein the cap substrate is manufactured to have an overflow area into which excess light-transmissive material can flow when the light-transmissive material is compressed using the heat tool.

20. The method according to claim 13, further comprising removing the heat tool from the light-transmissive material before placing the cap substrate in the curing environment.

21. The method according to claim 13, further comprising removing the heat tool from the light-transmissive material after placing the cap substrate in the curing environment.

22. The method according to claim 13, wherein placing the cap substrate in a curing environment includes placing the cap substrate in an oven.

23. The method according to claim 13, wherein placing the cap substrate in a curing environment includes irradiating the light-transmissive material with curing light.

24. The method according to claim 13, wherein the heat tool is used to compress the light-transmissive material to form the bottom surface of the light-transmissive material into a desired shape.

25. The method according to claim 13, wherein placing the cap substrate face down in the manufacturing environment includes: Place the top surface of the cap base facing downwards in a fixture, the fixture having a top surface facing the top surface of the cap.

26. The method according to claim 25, wherein the top surface of the fixture is shaped such that the hot tool is used to compress the light-transmissive material for shaping the top surface of the light-transmissive material into a shape opposite to the shape of the top surface of the fixture.

27. A cap for a light sensor, the cap comprising: a top wall; a side wall extending generally perpendicularly from and surrounding the top wall; a dividing side wall extending from a portion of the side wall to another portion of the side wall, thereby defining a first cavity and a second cavity; wherein the first cavity includes a central through-hole extending through the top wall and at least one release blind hole extending into but not through the top wall, wherein the at least one release blind hole intersects the central through-hole so as to be in fluid communication with the central through-hole; wherein the central through-hole is defined by an inner side wall extending through the top wall, and the central through-hole further includes a ridge extending outwardly from the inner side wall; and a light-transmissive aperture mounted within the central through-hole and butting against the ridge of the inner side wall.

28. The cap according to claim 27, wherein the light-transmissive aperture has a cavity defined in an outer side wall of the light-transmissive aperture for butting against the ridge of the inner side wall so as to mechanically anchor the light-transmissive aperture within the central through-hole.

29. The cap according to claim 27, wherein the central through-hole is circular and the at least one release blind hole is semi-circular.

30. A method of forming a cap for a light sensor module, the method comprising: manufacturing a cap base from a light-opaque material to form at least one opening in the cap base; placing the cap base with its top surface facing downwards in a manufacturing environment; dispensing a light-transmissive material into the at least one opening; placing the cap base in a curing environment, thereby manufacturing the cap for the light sensor module; wherein the cap base is manufactured such that a side wall defines the at least one opening, the side wall having at least one ridge extending from the side wall; and wherein a hot tool is used to compress the light-transmissive material for causing the light-transmissive material to flow around the at least one ridge.

31. The method according to claim 30, wherein the cap base is manufactured using injection molding.

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