Optical device

Abstract

The present invention provides an optical device comprising a substrate, an electronic component, a cover, and a barrier. The electronic component is disposed on the substrate. The electronic component has an active surface facing away from the substrate. The cover is disposed on the substrate. The cover has a wall structure extending toward and spaced apart from the active surface of the electronic component. The barrier is disposed on the active surface of the electronic component and spaced apart from the wall structure of the cover.

Description

[Technical Field]

[0001] This invention relates to optical devices, and more particularly to optical devices including blocking structures. [Previous Technology]

[0002] In optical systems (e.g., light scanning sensors, distance finding sensors, background light sensing systems), light emitters (e.g., vertical cavity surface-emitting lasers (VCSELs) or light-emitting diodes (LEDs)) and / or photodetectors are widely used to locate any object by detecting whether it is near the optical system or electronic components including the optical system. The light emitter is configured to emit light toward the target object, and the light reflected from the target object is received by the photodetector. However, some of the light emitted from the light emitter can directly enter the photodetector, which will cause an unacceptable crosstalk problem and reduce the signal-to-noise ratio (SNR) of the optical system. [Summary of the Invention]

[0003] According to one embodiment of the present invention, an optical device includes a substrate, an electronic component, a cover, and a barrier. The electronic component is disposed on the substrate. The electronic component has an active surface facing away from the substrate. The cover is disposed on the substrate. The cover has a wall structure extending toward and spaced apart from the active surface of the electronic component. The barrier is disposed on the active surface of the electronic component and spaced apart from the wall structure of the cover.

[0004] According to another embodiment of the present invention, the optical device includes a substrate, an electronic component, a barrier, and a cover. The electronic component is disposed on the substrate. The electronic component has an active surface facing away from the substrate. The barrier is disposed on the active surface of the electronic component. The cover is disposed on the substrate. The cover has a wall structure extending toward and spaced apart from the active surface of the electronic component. The barrier is spaced apart from and adjacent to at least one lateral surface of the wall structure of the cover.

[0005] According to another aspect of the present invention, a method for manufacturing an optical device includes (a) providing a substrate; (b) placing an electronic component on the substrate, the electronic component having an active surface facing away from the substrate; (c) placing a barrier on the active surface of the electronic component; (d) removing a portion of the barrier to form a groove; and (e) placing a cover disposed on the substrate, the cover having a wall structure extending within the groove and spaced apart from a sidewall and a bottom surface of the groove.

Implementation Method

[0016] FIG1A illustrates a cross-sectional view of an optical device 1 according to some embodiments of the present invention. The optical device 1 includes a substrate 10, a photodetector 11, an electronic component 12, a light emitter 13, a barrier (blocking structure or barrier wall) 14, a cover 15, lenses 16a, 16b, and a cover 17. In some embodiments, the optical device 1 in FIG1A may be a light scanning sensor, a distance finding sensor, a background light sensing system, a ToF sensor, or the like.

[0017] The substrate 10 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 polymer (PP). The substrate 10 may include interconnect structures, such as a plurality of conductive traces, pads, or vias. In some embodiments, the substrate 10 includes a ceramic material or a metal plate. In some embodiments, the substrate 10 may include an organic substrate or a lead frame. In some embodiments, the substrate 10 may include a dual-layer substrate, the dual-layer substrate including a core layer and a conductive material and / or a structure disposed on the upper and lower surfaces of the substrate 10. The conductive material and / or structure may include a plurality of traces, pads, or vias. In some embodiments, the substrate 10 includes a hole 10h (e.g., an vent hole) penetrating the substrate 10 to vent air within a cavity defined by the substrate 10, the cover 15, and the cap 17, which may mitigate or eliminate bursting problems.

[0018] Electronic component 12 (die or wafer) is disposed on substrate 10 and connected to substrate 10, for example, by means of flip chip or wire bonding technology. In some embodiments, as shown in FIG1A, electronic component 12 has an active surface 121 facing away from substrate 10 and is connected to substrate 10 by bonding wires. In some embodiments, electronic component 12 may be or include a controller, processor, memory, application-specific integrated circuit (ASIC) or the like.

[0019] A light emitter 13 is disposed on an electronic component 12. In some embodiments, the light emitter 13 is disposed on an active surface 121 of the electronic component 12 and is electrically connected to the electronic component 12 via bonding wires. In some embodiments, the light emitter 13 is configured to radiate light (e.g., L11) toward an object TB. The light emitter 13 may include an emitting die or other optical die. For example, the light emitter 13 may include a light-emitting diode (LED), a laser diode, a vertical cavity surface-emitting laser (VCSEL), or another device that may include one or more semiconductor layers. The semiconductor layers may include silicon, silicon carbide, gallium nitride, or any other semiconductor material.

[0020] The photodetector 11 is disposed on the substrate 10 and is physically separate from the light emitter 13 and the electronic component 12. In some embodiments, the photodetector 11 has an active region (or photodetector area) facing away from the substrate 10 and is configured to receive light reflected from the object TB (e.g., L12). In some embodiments, the photodetector 11 may include, for example, a PIN diode (including a diode comprising a p-type semiconductor region, an intrinsically semiconductor region, and an n-type semiconductor region), a photodiode, or a photoelectric crystal. In some embodiments, the photodetector 11 is an ambient light sensor (ALS). The photodetector 11 may be connected to the substrate 10, for example, by means of flip-chip or wire bonding technology.

[0021] A cover (or housing) 15 is disposed on a substrate 10. The cover 15 has a wall structure 15w extending from the cover 15 toward the electronic component 12. The wall structure 15w is disposed between the photodetector 11 and the light emitter 13. The wall structure 15w is disposed above the electronic component 12. In some embodiments, the wall structure 15w is spaced apart from the active surface 121 of the electronic component 12. For example, the wall structure 15w does not contact the active surface 121 of the electronic component 12. For example, there is a gap between the wall structure 15w and the active surface 121 of the electronic component 12. The cover 15 has an opaque material or a light-absorbing material to prevent unwanted light (e.g., L13) emitted by the light emitter 13 from being directly transmitted to the photodetector 11.

[0022] Barrier 14 is disposed on electronic component 12 (e.g., on active surface 121 of electronic component 12). Barrier 14 contacts active surface 121 of electronic component 12. In other embodiments, barrier 14 may contact active surface 121 and lateral surfaces of electronic component 12. Barrier 14 is spaced apart from cover 15 and wall structure 15w of cover 15. For example, there is a gap between barrier 14 and cover 15 or between barrier 14 and wall structure 15w of cover 15. Barrier 14 is disposed between light emitter 13 and photodetector 11 and adjacent to wall structure 15w of cover 15. As shown in FIG1A, barrier 14 is disposed between photodetector 11 and wall structure 15w. In some embodiments, barrier 14 may be disposed between wall structure 15w and light emitter 13. In some embodiments, barrier 14 may be disposed on both sides of wall structure 15w. For example, there are two barriers, one placed between the light emitter 13 and the wall structure 15w, and the other placed between the wall structure 15w and the light detector 11.

[0023] As shown in FIG1B (which is a perspective view illustrating the optical device 1 in FIG1A) (for clarity, the cover 15, lens 16, and cover 17 are omitted in FIG1B), a barrier 14 is disposed between the photodetector 11 and the electronic component 12 at position 15wp on which the wall structure 15w on which the cover 15 is disposed. In some embodiments, the barrier 14 may be disposed between the light emitter 13 and position 15wp. In some embodiments, the barrier 14 may be disposed on both sides of position 15wp. For example, there are two barriers, one disposed between the photodetector 11 and position 15wp and the other disposed between the light emitter 13 and position 15wp.

[0024] In some embodiments, the barrier 14 is formed of or includes an opaque or light-absorbing material. In some embodiments, the height of the barrier 14 is equal to or greater than the distance between the wall structure 15w and the active surface 121 of the electronic component 12. In some embodiments, the height of the barrier 14 is about 0.2 mm and the width of the barrier 14 is about 0.4 mm. In other embodiments, the height and width of the barrier 14 may be varied depending on different design requirements. The barrier 14 and the wall structure 15w of the cover 15 may, individually or collectively, prevent light emitted by the light emitter 13 from being directly transmitted to the photodetector 11. For example, light L14 passing through the gap between the wall structure 15w and the active surface 121 of the electronic component 12 may be blocked by the barrier 14. Compared to an optical device without barrier 14 (which only has a wall structure), the optical device 1 in FIG1A (which includes both the wall structure 15w and barrier 14) has better shielding capability, which can increase the signal-to-noise ratio (SNR) of the optical device 1. For example, the optical device without barrier 14 has an SNR of 14, while the optical device 1 in FIG1A has an SNR of 316.

[0025] In some embodiments, the barrier 14 is disposed between the wall structure 15w and the active surface 121 of the electronic component 12 and is in direct contact with both the wall structure 15w and the active surface 121 of the electronic component 12. However, during the manufacturing process of the optical device (e.g., reflow process), the barrier 14 will expand as the temperature increases. The expansion of the barrier 14 will compress the electronic component 12, thereby subjecting the electronic component 12 to stress, which may cause damage to the electronic component 12. In addition, since the two spaces / cavities (one for accommodating the light emitter 13 and the other for accommodating the photodetector 11) are completely separated or isolated by the wall structure 15w and the barrier 14, two vent holes are required for the cavities to avoid bursting problems, which will increase manufacturing costs and time.

[0026] According to the embodiment shown in FIG1A, since the cover 15 (the wall structure 15w of the cover 15) does not contact the barrier 14 or the electronic component 12, the barrier 14 and the wall structure 15w will not compress the electronic component 12 during the high-temperature process (e.g., reflow or curing process) used to manufacture the optical device 1 (e.g., stress-free), which prevents the electronic component 12 from breaking or being damaged. In addition, since the two cavities (one for accommodating the light emitter 13 and the other for accommodating the photodetector 11) are connected to each other (e.g., not completely sealed), only one hole 10h is needed to avoid bursting problems, which reduces manufacturing costs and time.

[0027] A cover 17 is disposed on a cover 15. The cover 17 defines apertures 17h1 and 17h2. The cover 15 defines apertures 15h1 and 15h2. Apertures 17h1 and 15h1 are above the photodetector 11. Apertures 17h2 and 15h2 are above the light emitter 13. A lens 16a is disposed within apertures 17h1 and 15h1. A lens 16b is disposed within apertures 17h2 and 15h2. Lenses 16a and 16b are configured to allow light emitted by the light emitter 13 (e.g., L11) and light reflected by the object TB (e.g., L12) to pass through. In some embodiments, lenses 16a and 16b are plano-convex lenses, which can increase optical density and improve the performance of the optical device 1.

[0028] FIG2 illustrates a cross-sectional view of an optical device 2 according to some embodiments of the present invention. The optical device 2 in FIG2 is similar to the optical device 1 in FIG1A, and the differences therebetween are described below.

[0029] As shown in FIG. 2, the photodetector is integrated into the electronic component 22. For example, the electronic component 22 includes a sensing area 22s (or photodetector area) facing away from the substrate 10 (or facing the lens 16b) to receive light. In some embodiments, the electronic component 22 may include a controller, processor, memory, ASIC, and the like. A light emitter 13 is disposed on the substrate 10 and spaced apart from the electronic component 22.

[0030] The wall structure 15w and the barrier 14 are disposed between the light emitter 13 and the sensing area 22s of the electronic component 22. The barrier 14 is disposed between the light emitter 13 and the wall structure 15w. In some embodiments, the barrier 14 may be disposed between the wall structure 15w and the sensing area 22s of the electronic component 22. In some embodiments, the barrier 14 may be disposed on both sides of the wall structure 15w. For example, there are two barriers, one disposed between the light emitter 13 and the wall structure 15w and the other disposed between the wall structure 15w and the sensing area 22s of the electronic component 22.

[0031] FIG3 illustrates a cross-sectional view of an optical device 3 according to some embodiments of the present invention. Except that the lenses in the optical device 3 are replaced by planar transmission films 36a and 36b, the optical device 3 in FIG3 is similar to the optical device 1 in FIG1A.

[0032] Flattened transmission films 36a and 36b are respectively disposed within apertures 17h1 and 17h2 defined by the cover 17. Flattened transmission films 36a and 36b are used to split and uniformly distribute light radiated toward the photodetector 11, thereby enhancing the uniformity of the light received by the photodetector 11. In some embodiments, flattened transmission films 36a and 36b are formed by applying transmission gel within apertures 17h1 and 17h2 or by transfer molding. In some embodiments, flattened transmission films 36a and 36b may comprise frosted glass, Teflon, holographic glass, opal glass, and grey glass. In some embodiments, flattened transmission films 36a and 36b may be formed of GaN or fused silica.

[0033] FIG4 illustrates a cross-sectional view of an optical device 4 according to some embodiments of the present invention. Except that the cover 47 in the optical device 4 is transmissive to allow light to pass through, the optical device 4 in FIG4 is similar to the optical device 1 in FIG1A. In some embodiments, the cover 47 may comprise a material similar to the flat transmissive films 36a and 36b shown in FIG3.

[0034] FIG5A illustrates a cross-sectional view of an optical device 5 according to some embodiments of the present invention. The optical device 5 in FIG5A is similar to the optical device 1 in FIG1A, and the differences therebetween are described below.

[0035] The optical device 5 includes a barrier 54 (or obstruction) disposed between the wall structure 15w of the cover 15 and the electronic component 12. The barrier 54 is located between two lateral surfaces of the cover 15. At least one lateral surface of the barrier 54 is located between the light emitter 13 and the photodetector 11. One lateral surface of the barrier 54 faces one lateral surface of the cover 15. The upper surface of the barrier 54 has a groove 54h (opening or aperture). The wall structure 15w extends toward the interior of the groove 54h. The wall structure 15w extends within the groove 54h of the barrier 54 without contacting the barrier 54. For example, the wall structure 15w is spaced apart from the lateral and bottom surfaces of the groove 54h. As shown in FIG5A, the barrier 54 may surround all lateral surfaces of the wall structure 15w. In other embodiments, as shown in FIG5B and FIG5C, the barriers 54', 54'' may surround only a portion of the lateral surfaces of the wall structure 15w. For example, in Figure 5B, barrier 54' is located only on the left side of wall structure 15w. For example, in Figure 5C, barrier 54" is located only on the right side of wall structure 15w.

[0036] The optical device 5 may include a light-transmitting material 55 (e.g., a transparent molding compound) disposed on the substrate 10 and covering the photodetector 11, electronic components 12, light emitter 13, and barrier 54. The light-transmitting material 55 covers the lateral and bottom surfaces of the groove 54h of the barrier 54. The light-transmitting material 55 surrounds the wall structure 15w. The light-transmitting material 55 is spaced apart from the cover 15 (including the wall structure 15w). For example, there is a gap between the light-transmitting material 55 and the wall structure 15w. In some embodiments, the light-transmitting material 55 includes protrusions 55p extending within the apertures 15h1 and 15h2 of the cover 15. In some embodiments, the protrusions 55p may define a plano-convex lens, which may increase light density and improve the performance of the optical device 5. In some embodiments, one of the protrusions 55p is located above the light detector 11 (e.g., above the light sensing area of ​​the light detector 11), and the other is located above the light emitter 13 (e.g., above the light emitting area of ​​the light emitter 13).

[0037] Since the barrier 54 is positioned below the wall structure 15w of the cover 15, no other area is needed on the electronic component 12 for placing the barrier 54. Therefore, the barrier 54 in FIG5A is suitable for electronic components where the area for placing additional objects on the active surface of the electronic component is relatively small or insufficient.

[0038] Figures 6A, 6A', 6B, and 6C illustrate methods for manufacturing optical devices according to some embodiments of the present invention. In some embodiments, the methods illustrated in Figures 6A, 6A', 6B, and 6C can be used to manufacture the optical device 5 shown in Figure 5A. Alternatively, the methods illustrated in Figures 6A, 6A', 6B, and 6C can be used to manufacture other optical devices.

[0039] Referring to FIG. 5A, a substrate 10 is provided. A photodetector 11 and an electronic component 12 are disposed on the substrate 10 and connected to the substrate 10 by means of, for example, wire bonding technology or any other suitable technology. A light emitter 13 is disposed on the active surface 121 of the electronic component 12. A barrier 54 is disposed on the active surface of the electronic component 12. The barrier 54 is disposed between the photodetector 11 and the light emitter 13. A light-transmitting material 55 including protrusions 55p is then formed on the substrate 10 to cover the photodetector 11, the electronic component 12, the light emitter 13, and the barrier 54. In some embodiments, one of the protrusions 55p is located above the photodetector 11 (e.g., above the light-sensing area of ​​the photodetector 11), and the other is located above the light emitter 13 (e.g., above the light-emitting area of ​​the light emitter 13). In some embodiments, the light-transmitting material 55 may be formed by molding technology (e.g., transfer molding, compression molding, or the like) or any other suitable technology.

[0040] In other embodiments, as shown in FIG6A' (a perspective view illustrating a portion of the structure in FIG6A), the barrier 54 may also be formed on the lateral surface of the electronic component 12. For example, the barrier 54 covers the active surface and both lateral surfaces of the electronic component 12. For example, the barrier 54 is positioned across the electronic component 12.

[0041] Referring to FIG6B, a portion of the light-transmitting material 55 and the barrier 54 is removed to form a groove 54h. In some embodiments, the light-transmitting material 55 and the barrier 54 may be removed by means of, for example, wiring, drilling, laser cutting or any other suitable process.

[0042] Referring to FIG6C, the cover 15 is placed on the substrate 10 and the wall structure 15w is placed in the groove 54h to form the optical device 5 as illustrated in FIG5A. The cover 15 has apertures 15h1 and 15h2 to expose the protruding portion 55p of the light-transmitting material 55.

[0043] As used herein, the terms “substantially,” “materially,” “approximately,” and “about” are used to describe and account for small 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, the thickness of a membrane or layer being “substantially uniform” may refer to a standard deviation of the average thickness of the membrane or layer less than or equal to ±10%, 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%. The term "substantially coplanar" can refer to two surfaces that are within 50 μm along the same plane (such as 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 "substantial," "substantial," "approximately," and "about" can refer to the exact occurrence of an event or situation as well as the approximate occurrence of an event or situation.

[0044] In the description of some embodiments, providing a component "on" another component may cover the case where the preceding component is directly on the following component (e.g., in physical contact with the following component) and the case where one or more intervening components are located between the preceding and following components.

[0045] In addition, quantities, ratios and other values ​​are sometimes presented in range format herein. It is understood that such range format is used for convenience and brevity and should be flexibly interpreted to include not only the values ​​explicitly specified as range limits, but also all individual values ​​or subranges covered within that range, as if each value and subrange were explicitly specified.

[0046] Although the invention has been described and illustrated with reference to specific embodiments thereof, such description and illustration are not intended to limit the invention. Those skilled in the art will readily understand 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 may not be drawn to scale. Due to variables in manufacturing processes, there may be differences between the artistic representation in the invention and the actual device. Other embodiments of the invention may exist that are not specifically described. The specification and drawings should be considered illustrative rather than restrictive. Modifications may be made to adapt specific circumstances, materials, composition, methods, or processes to the objectives, spirit, and scope of the invention. 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 particular order, it will be understood that these operations may be combined, subdivided, or reordered 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 intended to limit the invention. [Simplified Explanation of the Diagram]

[0006] FIG1A illustrates a cross-sectional view of an optical device according to some embodiments of the present invention;

[0007] FIG1B illustrates a perspective view of the optical device in FIG1A according to some embodiments of the present invention;

[0008] FIG2 illustrates a cross-sectional view of an optical device according to some embodiments of the present invention;

[0009] FIG3 illustrates a cross-sectional view of an optical device according to some embodiments of the present invention;

[0010] FIG4 illustrates a cross-sectional view of an optical device according to some embodiments of the present invention;

[0011] FIG5A illustrates a cross-sectional view of an optical device according to some embodiments of the present invention;

[0012] FIG5B illustrates an enlarged view of a portion of the optical device in FIG5A according to some embodiments of the present invention;

[0013] FIG5C illustrates a portion of the optical device in FIG5A according to some embodiments of the present invention;

[0014] Figures 6A, 6A', 6B and 6C illustrate a method for manufacturing an optical system according to some embodiments of the present invention;

[0015] Common reference numerals are used throughout the drawings and embodiments to indicate the same or similar components. The invention can be best understood in conjunction with the accompanying drawings and the following embodiments.

Claims

1. An optical device comprising: a substrate; a barrier disposed on the substrate, wherein one upper surface of the barrier has a groove; and a cover disposed on the substrate, the cover having a first structure extending parallel to the substrate and a wall structure extending from the first structure toward the interior of the groove, wherein the barrier is located between two lateral surfaces of the cover, wherein one length of the wall structure in a vertical direction is less than one length of the first structure of the cover in a horizontal direction, wherein the upper surface of the groove of the barrier is non-planar, and wherein the wall structure extends within the groove of the barrier without contacting the barrier.

2. The optical device of claim 1, further comprising: A light detector is mounted on the substrate; A light emitter is mounted on the substrate; And a light-transmitting material disposed on the substrate and covering the barrier, the photodetector and the light emitter.

3. The optical device of claim 2, further comprising an electronic component disposed on the substrate, wherein the barrier and the light emitter are disposed on a top surface of the electronic component, wherein at least one side surface of the barrier is located between the light emitter and the light detector.

4. The optical device of claim 2, wherein the cover has a first aperture above the light emitter and a second aperture above the light detector, and the light-transmitting material is at least partially disposed in the first aperture and the second aperture.

5. The optical device of claim 4, further comprising a wire that electrically connects the photodetector to the substrate, wherein the light-transmitting material covers the wire.

6. The optical device of claim 5, wherein the conductor at least partially overlaps perpendicularly with the second aperture.

7. The optical device of claim 2, wherein one bottom surface of the barrier is at substantially the same height as one bottom surface of the light emitter, wherein, relative to the substrate, one bottom surface of the barrier structure is higher than one top surface of the light emitter.

8. The optical device of claim 1, wherein the groove of the barrier has a lateral surface facing one of the lateral surfaces of the wall structure.

9. An optical device comprising: a substrate; a barrier disposed on the substrate; a cover disposed on the substrate, the cover having a first structure extending parallel to the substrate and a wall structure extending from the first structure toward the substrate, wherein the barrier covers a first sidewall, a second sidewall, and a bottom surface of the wall structure, and wherein the first sidewall and the second sidewall are connected through the bottom surface, wherein a length of the wall structure in a vertical direction is less than a length of the first structure of the cover in a horizontal direction; a light-transmitting material disposed on the substrate, wherein a portion of the light-transmitting material is disposed between the cover and the barrier and perpendicularly overlaps the cover and the barrier; a light emitter disposed on the substrate, wherein a portion of the barrier is disposed between the wall structure and the light emitter, wherein, in a cross-sectional view, a width of the wall structure is greater than a width of the light emitter; and a light detector disposed on the substrate, wherein another portion of the barrier is disposed between the wall structure and the light detector. The cover defines a first cavity that houses one of the light emitters and a second cavity that houses one of the light detectors. The light-transmitting material is located in the first cavity and the second cavity to cover the light emitter and the light detector. The first cavity is connected to the second cavity through the gap between the wall structure and the barrier.

10. The optical device of claim 9, wherein one of the upper surfaces of the barrier has a groove, wherein the wall structure extends toward the interior of the groove, and wherein the barrier is located between two lateral surfaces of the cover.

11. The optical device of claim 9, wherein the barrier is at least partially disposed between the bottom surface of the wall structure of the cover and one of the upper surfaces of the substrate, wherein the barrier is located only on one side of the wall structure.

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