Photovoltaic module and wafer-level method for manufacturing a photovoltaic module

Abstract

A device includes an optoelectronic component mounted to a PCB substrate. A transmissive adhesive is disposed directly on the optoelectronic component and transmits light of a wavelength sensed by or emitted by the optoelectronic component. The device includes an optical filter disposed directly on the transmissive adhesive. An epoxy laterally surrounds and contacts the side surfaces of the transmissive adhesive and the optical filter. The epoxy does not transmit light of a wavelength sensed by or emitted by the optoelectronic component. In some cases, the epoxy defines a groove directly above the optical filter for accommodating an optical component such as an optical diffuser. A method of manufacturing a module is also disclosed.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 639,700, filed on March 7, 2018. The contents of the prior application are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates to photovoltaic modules and wafer-level methods for manufacturing the modules. Background Art

[0004] Various consumer electronic products such as smart phones and other host computing devices include compact optoelectronic modules with integrated light sensing or light emitting devices. In some cases, space is at a premium in the host device. Therefore, it is desirable to make the module as small and compact as possible. Due to manufacturing and other tolerances, the size (e.g., height) of the module tends to vary. However, it is desirable to obtain greater consistency for the module. Summary of the invention

[0005] The present disclosure describes photovoltaic modules and methods of manufacturing such modules in wafer-level processing.

[0006] For example, in one aspect, the present disclosure describes a device including an optoelectronic component mounted to a PCB substrate. A transmissive adhesive is disposed directly on the optoelectronic component and transmits light of a wavelength sensed by or emitted by the optoelectronic component. The device includes an optical filter disposed directly on the transmissive adhesive, and an epoxy resin laterally surrounding and contacting the side surfaces of the transmissive adhesive and the optical filter. The epoxy resin does not transmit light of a wavelength sensed by or emitted by the optoelectronic component.

[0007] Some embodiments include one or more of the following features. For example, the epoxy can define a groove that accommodates an optical component (e.g., a light diffuser) directly above the filter. Preferably, there is no air gap between the optoelectronic component and the filter due to the presence of the transmissive adhesive. The epoxy can be, for example, a black epoxy.

[0008] In some cases, the optoelectronic component may be operable to emit light. In other cases, the optoelectronic component may be operable to sense light. In either case, the transmissive adhesive and the filter may be disposed to intersect the optical axis of the optoelectronic component.

[0009] The modules as described in the present disclosure can be integrated into a host device such as a smart phone or other portable computing device. Therefore, in another aspect, the present disclosure describes an apparatus including a host device and an optoelectronic module, the host device including a processor and a display screen. The optoelectronic module may include features described above and / or in more detail below. The processor is operable to control features of the host device based at least in part on signals from the optoelectronic component.

[0010] On the other hand, the present disclosure describes a method for manufacturing an optoelectronic module. The method includes holding a PCB wafer in a first vacuum injection molding tool, wherein a plurality of optoelectronic components are mounted on the PCB wafer, each of the optoelectronic components having a corresponding amount of unhardened transmissive adhesive on a surface intersecting an optical axis of the optoelectronic component, wherein the adhesive transmits light of a wavelength sensed by the optoelectronic component or emitted by the optoelectronic component. The method further includes providing a second vacuum injection molding tool, which includes an elastomer layer having a structured surface, and a plurality of filters are mounted on the structured surface. The first vacuum injection molding tool and the second vacuum injection molding tool are brought close to each other to squeeze the filter into contact with the unhardened transmissive adhesive. Subsequently, the transmissive adhesive is hardened. The method includes injecting epoxy resin into a space between the elastomer layer of the second vacuum injection molding tool and the PCB wafer, so that the epoxy resin laterally surrounds and contacts the side surfaces of the transmissive adhesive and the filter, wherein the epoxy resin does not transmit light of a wavelength sensed by the optoelectronic component or emitted by the optoelectronic component. The epoxy resin is hardened. The method includes cutting through the black epoxy resin to form segmented modules, each of which includes at least one of the optoelectronic components.

[0011] Some embodiments include one or more of the following features. For example, the method may include selectively dispensing an unhardened transmissive adhesive onto a surface of each respective optoelectronic component such that the adhesive intersects an optical axis of the optoelectronic component. In some cases, a sealing plate is disposed on the elastomer layer and defines a precise height separating the first vacuum injection molding tool and the second vacuum injection molding tool when the first vacuum injection molding tool and the second vacuum injection molding tool are combined to press the filter into contact with the unhardened transmissive adhesive.

[0012] Various advantages can be achieved in some embodiments. For example, in some cases, the manufacturing process can result in greater uniformity between modules (eg, greater uniformity in their thickness).

[0013] Other aspects, features, and advantages will be apparent from the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figures 1 to 8 The individual steps in a method of manufacturing a photovoltaic module are shown.

[0015] Fig. 9 An example of a photovoltaic module is shown. DETAILED DESCRIPTION

[0016] The present disclosure describes wafer-level manufacturing techniques for preparing multiple optoelectronic modules simultaneously and in parallel. Each module includes an optoelectronic component, such as a light emitting die or a light receiver die (e.g., an integrated circuit semiconductor chip). Examples of light emitting components include light emitting diodes (LEDs), infrared (IR) LEDs, organic LEDs (OLEDs), infrared (IR) laser diodes, vertical cavity surface emitting lasers (VCSELs), and arrays of such devices. Examples of light receiver components include image sensors, photodiodes, and arrays of such devices. Associated processing circuits can be implemented in the same integrated circuit semiconductor chip, which can include, for example, appropriate logic and / or other hardware components (e.g., readout registers; amplifiers; analog-to-digital converters; clock drivers; timing logic; signal processing circuits; and / or microprocessors).

[0017] Each module also includes an optical filter disposed directly above the optoelectronic component and intersecting the optical axis of the optoelectronic component. To accommodate slight differences in thickness between the various optoelectronic components during the manufacturing process, a transparent adhesive is provided between each optical filter and the upper surface of the associated optoelectronic component. The use of a transparent adhesive in the manufacturing process can result in greater uniformity between modules (e.g., greater uniformity in their thickness).

[0018] The following paragraphs describe an example of a wafer-level process.

[0019] like Figure 1 As shown in FIG, a plurality of optoelectronic components 26 are mounted to a printed circuit board (PCB) wafer 24 via respective die pads 28. Bonding wires 30 may provide electrical connections from conductive pads on the optoelectronic components 26 to conductive pads on the PCB wafer 24. The bonding wires 30 may be encapsulated, for example, by a protective adhesive or epoxy resin. The PCB wafer 24 is attached to a transparent rigid carrier 20 composed, for example, of glass, via double-sided tape 22.

[0020] Next, if Figure 2As shown, a small amount of transparent adhesive material 32 is dispensed onto the top surface of each optoelectronic component 26. The adhesive material 32 can be, for example, an epoxy resin that transmits a wavelength of light (e.g., visible light or infrared light) emitted by the optoelectronic component 26 or detectable by the optoelectronic component 26. In some cases, the transparent adhesive 32 has a relatively high viscosity. Further, the transparent adhesive 32 can have a relatively small coefficient of thermal expansion (CTE). Specifically, in some cases, the CTE of the transparent adhesive 32 is the same as or very close to the CTE of the photosensitive component or the light emitting component (e.g., close enough to prevent cracking, breaking, delamination or other mechanical defects when manufacturing the optoelectronic module).

[0021] like Figure 3 , a vacuum injection molding (VIM) tool 40, which may also be referred to as a baffle tool, includes a structured elastomeric layer 44 on a rigid substrate 42. The rigid substrate 42 may be composed of, for example, glass. The elastomeric layer 44 may be composed of, for example, polydimethylsiloxane (PDMS), and includes protrusions 46 that extend slightly beyond a major surface 50 of the elastomeric layer 44. Each protrusion 46 preferably has a width (i.e., in the xy direction parallel to the plane of the PCB wafer 24) that is slightly larger than the width of the filter 48.

[0022] Next, if Figure 4 As shown in , a corresponding filter 48 is placed on each of the protrusions 46 of the PDMS layer 44. The filter 48 can be placed, for example, by a pick-and-place device. In some cases, a radiochromic film (RCF) can be provided as the filter 48.

[0023] like Figure 5 As shown in FIG. 1 , a transparent rigid carrier 20 with a PCB wafer 24 mounted thereon is placed on a lower VIM tool 50, which may also be referred to as a substrate tool. The substrate tool 50 comprises an elastomeric (e.g., PDMS) layer 52 on a rigid substrate 54, for example, composed of glass. A sealing plate 55 having a large central opening is disposed on the elastomeric layer 52 close to its periphery and defines a precise height, such as when the sealing plate 55 is placed on the lower VIM tool 50. Figure 6 This precise height separates the upper VIM tool 40 and the lower VIM tool 50 when they are combined together as shown in FIG.

[0024] When the upper VIM tool 40 and the lower VIM tool 50 are combined, the filter 48 presses the corresponding area in the area of ​​the transparent adhesive 32 previously deposited on the optoelectronic component 26, thereby flattening the adhesive 32. The transparent adhesive 32 can then be hardened, for example, by UV or thermal curing. Spaces 58 remain between the elastomer layer 44 of the upper tool 40 and the PCB wafer 24. In a subsequent step, these spaces 58 are filled with black epoxy resin.

[0025] Because the sealing plate 55 fixes the distance between the upper VIM tool 40 and the lower VIM tool 50, and because the rigid substrate 54 helps prevent the PCB wafer 24 from bending, the overall height from the bottom of a particular optoelectronic component 26 to the top of the adhesive material 48 is substantially consistent from component to component. In this way, the transparent adhesive 32 helps accommodate variations in the thickness of the photosensitive or light emitting component 26.

[0026] Next, if Figure 7 As shown in , while the upper VIM tool 40 and the lower VIM tool 50 remain in place, a black epoxy 60 is injected and fills the space 58 by the VIM process. The black epoxy 60 can then be hardened, for example, by UV and / or thermal curing. In some cases, this can be done while the upper tool 40 and the lower tool 50 remain in place. Thus, the black epoxy 60 encapsulates the optoelectronic components 26 and laterally surrounds the transparent adhesive 32 and the filter 48. As shown in FIG. Figure 7 As shown, black epoxy 60 is in contact with the adhesive 32 and the side surfaces of the filter 48. Although the injected epoxy 60 may be referred to as black epoxy, more generally, the epoxy 60 should not transmit light of wavelengths sensed or emitted by the optoelectronic components 26 mounted on the PCB wafer 24. After the epoxy material 60 is hardened, the VIM tools 40, 50 are removed (see FIG. Figure 8 ).

[0027] In some cases, narrow vertical grooves are formed through the black epoxy 60. The grooves preferably extend partially into the PCB wafer 24 and are used to relieve stress. The grooves can be formed, for example, by cutting and separate adjacent optoelectronic components 26 from each other. In some cases, in addition, larger grooves can be formed closer to the edge of the PCB wafer 24 and can provide assistance during the subsequent release of the PCB wafer 24 from the tape 22. In some cases, the intermediate carrier is attached to the top of the assembly (i.e., on the outer surface of the black epoxy 60) while applying heat to remove the double-sided tape 22 and the rigid carrier 20.

[0028] Then, during the final singulation process (eg, dicing), the partially separated modules can be completely separated from each other. The result is a plurality of singulated modules 100 (see Fig. 9 ), each of which includes an optoelectronic component 26 mounted on a PCB substrate 104 via a die pad 106, an optical filter 48 disposed just above the optoelectronic component, and a transparent adhesive 32 between the optical filter and the upper surface of the optoelectronic component. The transparent adhesive 32 contacts the upper surface of the optoelectronic component 26 and the lower surface of the optical filter 48. Therefore, there is no air gap between the optoelectronic component 26 and the optical filter 48. As described above, the above process can result in less variation in module height and therefore more consistency between modules.

[0029] from Fig. 9 It can be seen that the black epoxy 60 encapsulates the optoelectronic component 26 and laterally surrounds the transparent adhesive 32 and the filter 48. The black epoxy 60 also defines a plurality of grooves: a first groove 62 accommodates the filter 48, and a second groove 64 can accommodate another optical component (e.g., a light diffuser or lens, etc.). The VIM process described above allows the two grooves to be formed simultaneously. Fig. 9 As shown in , the width of the second groove 64 may be slightly larger than the width of the filter 48 .

[0030] Module 100 may also include bond wires 108 that provide electrical connections between bond pads on top of optoelectronic components 26 and additional bond pads on PCB substrate 104. In some cases, bond wires 108 may be encapsulated with epoxy prior to performing the VIM process described above.

[0031] The modules 100 described herein can be integrated into a variety of portable computing devices, such as smartphones, wearable devices, bio-devices, mobile robots, surveillance cameras, camcorders, laptops, and tablet computers, etc. The modules 100 may include SMT or other pads 102 on their backs to allow the modules to be mounted, for example, on a PCB flex cable in a host device. These modules can be used, for example, as optical sensing modules, such as for gesture sensing or recognition.

[0032] The designs of smart phones and other portable computing devices referenced in this disclosure may include one or more processors, one or more memories (e.g., RAM), storage (e.g., disk or flash memory), a user interface (which may include, for example, a keyboard, a TFT LCD or OLED display, a touch or other gesture sensor, a camera or other optical sensor, a compass sensor, a 3D magnetometer, a 3-axis accelerometer, a 3-axis gyroscope, one or more microphones, etc., and software instructions for providing a graphical user interface), interconnections (e.g., buses) between these elements, and interfaces for communicating with other devices (which may be wireless such as GSM, 3G, 4G, CDMA, WiFi, WiMax, Zigbee, or Bluetooth, and / or wired such as through an Ethernet LAN, T-1 Internet connection). In some cases, one or more processors use signals from the module (e.g., signals from the receiver die 24) to adjust the brightness of the display screen of the host device.

[0033] Various modifications will be apparent, and various modifications may be made to the foregoing examples. Features described in conjunction with different embodiments may be incorporated into the same embodiment in some cases, and various features described in conjunction with the foregoing examples may be omitted from some embodiments. Therefore, other embodiments are within the scope of the claims.

Claims

1. A device comprising an optoelectronic component, comprising: Optoelectronic components mounted to a PCB substrate; a transmissive adhesive disposed directly on the optoelectronic component, wherein the adhesive transmits light at a wavelength sensed by or emitted by the optoelectronic component; an optical filter disposed directly on the transmissive adhesive; as well as an epoxy laterally surrounding and contacting the transmissive adhesive and side surfaces of the filter, wherein the epoxy does not transmit light of a wavelength sensed by or emitted by the optoelectronic component; and Wherein a coefficient of thermal expansion of the transmissive adhesive is approximately the same as a coefficient of thermal expansion of the optoelectronic component.

2. The device of claim 1, wherein the epoxy defines a recess directly above the filter that receives an optical component.

3. The device of claim 1, wherein the epoxy defines a recess directly above the filter that accommodates a light diffuser.

4. The device of claim 1, wherein no air gap exists between the optoelectronic component and the filter. The device of claim 1 , wherein the optoelectronic component is operable to emit light. The device of claim 1 , wherein the optoelectronic component is operable to sense light.

7. The device of claim 1, wherein the epoxy is a black epoxy.

8. The device of claim 1, wherein the transmissive adhesive and the optical filter are disposed to intersect an optical axis of the optoelectronic component.

9. A device comprising a photovoltaic module, comprising: a host device including a processor and a display; The optoelectronic module in the host device comprises: an optoelectronic component mounted to a PCB substrate; a transmissive adhesive directly disposed on the optoelectronic component, wherein the adhesive transmits light of a wavelength sensed by the optoelectronic component or emitted by the optoelectronic component; an optical filter directly disposed on the transmissive adhesive; and an epoxy resin laterally surrounding and contacting side surfaces of the transmissive adhesive and the optical filter, wherein the epoxy resin does not transmit light of a wavelength sensed by the optoelectronic component or emitted by the optoelectronic component, wherein the processor is operable to control a feature of the host device based at least in part on a signal from the optoelectronic component, and Wherein a coefficient of thermal expansion of the transmissive adhesive is approximately the same as a coefficient of thermal expansion of the optoelectronic component.

10. The device of claim 9, wherein the transmissive adhesive and the filter are disposed to intersect an optical axis of the optoelectronic component.

11. The device of claim 9, wherein the epoxy defines a recess directly above the filter that accommodates a light diffuser.

12. The device of claim 9, wherein no air gap exists between the optoelectronic component and the filter.

13. The device of claim 9, wherein the optoelectronic component is operable to emit light.

14. The device of claim 9, wherein the optoelectronic component is operable to sense light.

15. The device of claim 9, wherein the epoxy is a black epoxy.

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