Reinforcing structure for COB module and ADAS camera

Abstract

The utility model provides a COB module reinforcing structure and an ADAS camera, the COB module comprises a substrate and a sensor electrically connected with the substrate, the COB module reinforcing structure comprises a heat conduction adhesive layer and a heat dissipation layer, the heat conduction adhesive layer and the heat dissipation layer are sequentially stacked on one side of the substrate away from the sensor, and the heat dissipation layer is electrically connected with the sensor. The heat dissipation layer is a silicon wafer, white glass or a steel plate and is used for heat dissipation and reinforcement of the COB module so as to reduce the deformation of the substrate of the COB module.

Description

Technical Field

[0001] The utility model relates to the technical field of chip reinforcement, in particular to a reinforcement structure for a COB module and an ADAS camera. Background Art

[0002] The COB (Chip On Board) process is a technology that directly mounts a bare chip on a PCB (printed circuit board) and achieves electrical connection through wire bonding.

[0003] At present, most car cameras are in the shape of small closed cubes, and they do not have active cooling function, which makes it easy for the chip on the COB module inside the car camera to accumulate too much heat and heat up quickly after operation, causing circuit damage, thus affecting the service life of the camera. When the camera stops operating and rapidly cools back to room temperature, thermal expansion and contraction cause corresponding stress changes in the internal electronic components and the PCB (printed circuit board). Since the rated operating temperature of image sensors is typically –40°C to 125°C (junction temperature) and –40°C to 105°C (ambient temperature), operating above this rated operating temperature can cause thermal expansion between the electronic components and the PCB. This can cause the front of the PCBA (where the sensor is attached) to heat up due to the high power consumption of the chip itself. This can significantly stretch the PCBA and cause micro-deformation. Furthermore, internal thermal simulation analysis revealed 10-20 μm edge warpage in the PCBA. This 10-20 μm change is sufficient to degrade the lens module's MTF (Modulation Transfer Function), which reflects the lens's ability to resolve image detail. This can affect the image sensor's image quality in the back-end electronic control unit (ECU), causing the sensor to completely shut down or output erroneous image detection signals.

[0004] The photoelectric effect of the image sensor and the temperature drift of the lens, especially in lenses with more than 8 megapixels, require that PCB deformation be controlled within ±3µm to ensure a relatively clear image across the full operating temperature range. If this deviation is exceeded, the electronic control unit (ECU) may restrict camera use by prematurely or delaying shutdown or output erroneous algorithmic judgments. These miscalculations could potentially cause accidents. Utility Model Content

[0005] In view of this, an object of the present invention is to provide a reinforcement structure for a COB module, aiming to reduce the deformation of the substrate of the COB module.

[0006] The utility model provides a reinforcement structure for a COB module. The COB module includes a substrate and a sensor electrically connected to the substrate. The reinforcement structure includes a thermally conductive adhesive layer and a heat dissipation layer. The thermally conductive adhesive layer and the heat dissipation layer are stacked in sequence on a side of the substrate facing away from the sensor. The heat dissipation layer is a silicon wafer, white glass or steel plate, and is used to dissipate heat and reinforce the COB module.

[0007] In one embodiment, the thermally conductive adhesive layer is a thermally conductive silver adhesive layer.

[0008] In one embodiment, the heat dissipation layer has a thickness of 0.3 mm to 3 mm.

[0009] The present invention also provides an ADAS camera, including a camera module, a COB module, a flexible circuit board and the reinforcement structure for the COB module as described above, wherein the camera module, the COB module, the reinforcement structure for the COB module and the flexible circuit board are stacked in sequence.

[0010] In one embodiment, the camera module includes a lens and a lens mount, and the lens is fixed to the COB module via the lens mount to increase the contact area between the COB module and the lens.

[0011] In one embodiment, the substrate is a PCB board, and the heat dissipation layer is a silicon wafer or white glass.

[0012] In one embodiment, the substrate is an FPC board, and the heat dissipation layer is a steel plate.

[0013] In one embodiment, an attachment layer is further included, and the attachment layer is a heat-conductive silver adhesive layer, which is used to attach the sensor to the substrate.

[0014] In one embodiment, the lens and the lens mount are connected via a first curing adhesive layer.

[0015] In one embodiment, the reinforcement structure for the COB module is connected to the flexible circuit board via a heterogeneous conductive adhesive layer.

[0016] The reinforcement structure for the COB module provided by the present invention provides a heat dissipation layer on the opposite side of the sensor packaged in the substrate of the COB module, and adheres it with a thermally conductive adhesive layer, which serves as a thermal bridge between the substrate and the heat dissipation layer, thereby transferring the heat generated by the COB module to the heat dissipation layer for heat dissipation, thereby reducing the risk of deformation of the substrate caused by high power consumption and heat generation of the sensor, and ensuring the normal operation of the image sensor. The silicon wafer, white glass and steel plate have better heat dissipation or reinforcement effects, further improving the reinforcement effect of the COB module. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Schematic diagram of the reinforcement structure for the COB module in the first embodiment of the present invention.

[0019] Figure 2 Schematic diagram of the structure of the ADSA camera in the second embodiment of the present invention.

[0020] Figure numerals: 10, COB module; 11, substrate; 12, sensor; 20, thermally conductive adhesive layer; 30, heat dissipation layer; 40, camera module; 41, lens; 42, lens mount; 43, first cured adhesive layer; 50, flexible circuit board; 60, attachment layer; 70, anisotropic conductive adhesive layer; 80, label paper; 90, second cured adhesive layer. DETAILED DESCRIPTION

[0021] The following is a detailed description of a specific embodiment of the present invention in conjunction with the accompanying drawings. Based on the description of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0022] In the description of this utility model, unless otherwise specified or limited, the terms "disposed," "installed," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms based on the specific circumstances.

[0023] The directions or positional relationships indicated by terms such as "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience and simplification of description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the utility model.

[0024] The terms "first," "second," "third," etc. are merely used to distinguish elements of similar nature and do not indicate or imply relative importance or a particular order.

[0025] The terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than the listed elements and may also include additional elements not specifically listed.

[0026] First embodiment

[0027] Please refer to Figure 1 The utility model discloses a reinforcement structure for a COB module. The COB module 10 includes a substrate 11 and a sensor 12 electrically connected to the substrate 11. The reinforcement structure includes a thermally conductive adhesive layer 20 and a heat dissipation layer 30. The thermally conductive adhesive layer 20 and the heat dissipation layer 30 are stacked in sequence on the side of the substrate 11 away from the sensor 12. The heat dissipation layer 30 is a silicon wafer, white glass or steel plate, and is used to dissipate heat and reinforce the COB module 10.

[0028] Specifically, the sensor 12 is electrically connected to the substrate 11 and integrated onto the substrate 11. Specifically, the sensor 12 is encapsulated and cured on the substrate 11 using epoxy resin through a mold to form a COB module, simplifying the packaging process. However, because the chip thickness of the COB module 10 under the 8-megapixel lens 41 is much thinner than that of a standard packaged chip, the substrate 11 is subject to the heat generated by the sensor 12 and the stress effects of thermal expansion and contraction of the substrate 11 at high and low temperatures, which can easily damage the chip. Issues such as chip attachment accuracy, such as warping, offset, and tilt, need to be addressed urgently. For cameras with higher resolution and reliability requirements above 8 megapixels, relying solely on temperature-sensitive adhesives such as glue to secure the substrate 11 and sensor 12 cannot guarantee that the substrate 11 will not affect the sensor 12 under prolonged heating. It may even cause slight warping in the area where the sensor 12 is attached due to the combined heat and stress of the substrate 11. This can significantly affect the module's MTF (mean temperature function) and result in slightly blurred images. This can cause the autonomous driving algorithm to misjudge, potentially leading to accidents. However, in this embodiment, a heat dissipation layer 30 is attached to the side of the substrate 11 opposite to the sensor 12, which can promote the heat dissipation of the COB model. The heat dissipation layer 30 is attached to the substrate 11 through the thermally conductive adhesive layer 20, which can accelerate the heat conduction to the heat dissipation layer 30, further promote the volatilization of heat by the heat dissipation layer 30, and avoid precision problems such as warping, offset and tilting caused by heat accumulation when attaching the sensor 12 chip.

[0029] The heat dissipation layer 30 can achieve good heat dissipation effect by using silicon wafers, white glass or steel plates. In particular, the silicon wafer and the sensor 12 chip have the same composition. Through heat transfer, the heat dissipation on both sides of the substrate 11 can be balanced, thereby achieving stress compensation balance on both sides of the substrate 11, thereby avoiding thermal deformation of the COB module 10 and achieving the effect of strengthening the substrate 11. When used in the field of camera equipment, the system reliability of the camera can be improved to reduce the impact of the heat generated by the sensor 12 on the image clarity.

[0030] In this embodiment, the thermally conductive adhesive layer 20 is a thermally conductive silver adhesive layer.

[0031] Specifically, silver glue has the advantages of high temperature resistance, heat conductivity, and electrical conductivity. The heat dissipation layer 30 is attached to the substrate 11 through the heat-conductive silver glue layer, which can effectively resist the heat generated by the sensor 12, ensure that it does not deform, and play an effective heat conduction effect.

[0032] In this embodiment, the thickness of the heat dissipation layer 30 is 0.3 mm-3 mm.

[0033] Specifically, a thinner heat dissipation layer 30 can reduce the overall thickness of the product, store less heat, and dissipate heat faster. However, when the heat dissipation layer 30 is made of silicon wafers or white glass, a thickness of less than 0.3 mm can easily lead to excessive brittleness and fragility. Too thick a layer is not conducive to heat dissipation, assembly, and lightweighting of the product. In actual applications, the thickness of the heat dissipation layer 30 can be 0.38mm, 0.47mm, 0.56mm, 0.60mm, 0.68mm, 0.75mm, 0.80mm, 0.85mm, 0.90mm, 1.00mm, 1.15mm, 1.26mm, 1.37mm, 1.45mm, 1.57mm, 1.66mm, 1.72mm, 1.83mm, 1.90mm, 2.11mm, 2.28mm, 2.37mm, 2.49mm, 2.56mm, 2.67mm, 2.74mm, 2.85mm, 2.96mm, etc., which is not a sole limitation here.

[0034] Furthermore, the thickness of the heat dissipation layer 30 is preferably 0.80 mm to 1.20 mm.

[0035] The reinforcement structure for the COB module provided by the present invention provides a heat dissipation layer 30 on the opposite side of the substrate 11 of the COB module 10 where the sensor 12 is encapsulated, and is attached with a thermally conductive adhesive layer 20, which serves as a thermal bridge between the substrate 11 and the heat dissipation layer 30, thereby transferring the heat generated by the COB module 10 to the heat dissipation layer 30 for heat dissipation, thereby reducing the risk of deformation of the substrate 11 caused by high power consumption and heat generation of the sensor 12, and ensuring the normal operation of the image sensor 12. The silicon wafer, white glass and steel plate have better heat dissipation or reinforcement effects, further improving the reinforcement effect of the COB module 10.

[0036] Second embodiment

[0037] Please refer to Figure 2 Another embodiment of the present invention further provides an ADAS camera, including a lens assembly 40, a COB module 10, a flexible circuit board 50 and a reinforcement structure for the COB module as described in the first embodiment, wherein the lens assembly 40, the COB module 10, the reinforcement structure for the COB module and the flexible circuit board 50 are stacked in sequence.

[0038] Specifically, in-vehicle ADAS (Advanced Driving Assistance System) cameras have gradually become a mainstream feature of autonomous driving. The pixel requirement for ADAS cameras has increased from 1 million to 8 million pixels, leading to increased power consumption of the sensor 12 within the product, causing it to overheat. Incorporating a reinforced structure for the COB module in ADAS cameras can effectively address the issue of blurred display caused by sensor 12 overheating, thus preventing driving accidents.

[0039] In this embodiment, the lens assembly 40 includes a lens 41 and a lens mount 42 . The lens 41 is fixed to the COB module 10 via the lens mount 42 , so as to increase the contact area between the COB module 10 and the lens 41 .

[0040] Specifically, the structure inside the lens 41 is extremely sophisticated, and the connection through the lens mount 42 helps stabilize the lens 41. The lens mount 42 also isolates the COB module 10 and the lens 41, preventing the heat generated by the sensor 12 of the COB module 10 from affecting the sensitivity of the chip inside the lens 41. The lens mount 42 also increases the contact area between the lens assembly 40 and the COB module 10, making the connection between the two more stable.

[0041] In this embodiment, the lens 41 and the lens mount 42 are connected via a first curing adhesive layer 43 .

[0042] Specifically, the lens 41 is inserted into the lens mount 42, and an uncured first curing adhesive layer 43 is injected into the connection gap between the lens 41 and the lens mount 42. After the first curing adhesive layer 43 is evenly spread, it can be irradiated with ultraviolet light for curing, and the lens 41 and the lens mount 42 are relatively fixed. The first curing adhesive layer 43 can fill the gap in the connection to prevent contamination caused by debris entering or unstable connection caused by discontinuous filling.

[0043] In this embodiment, the lens holder 42 and the COB module 10 are attached and connected via a second curing adhesive layer 90 .

[0044] Furthermore, the first curing adhesive layer 43 and the second curing adhesive layer 90 are both UV curing adhesives.

[0045] In this embodiment, the substrate 11 is a PCB board, and the heat dissipation layer 30 is a silicon wafer or white glass.

[0046] Specifically, the PCB board is usually a rigid substrate, and there is no need to consider rigid reinforcement during the reinforcement design. It is sufficient to only attach a silicon wafer or white glass. Both the silicon wafer and the white glass contain silicon, which has an excellent effect on the thermal conductivity of the sensor 12 chip, which is also a silicon product.

[0047] In this embodiment, an attachment layer 60 is further included. The attachment layer 60 is a heat-conductive silver adhesive layer, and is used to attach the sensor 12 to the substrate 11 .

[0048] Specifically, the heat-conductive silver adhesive layer is electrically conductive and can transfer the heat of the sensor 12 to the substrate 11 and then to the heat-conductive adhesive layer 20 and the heat dissipation layer 30 , thereby accelerating the heat transfer.

[0049] In this embodiment, the reinforcement structure for the COB module is connected to the flexible circuit board 50 through a heterogeneous conductive adhesive layer 70. Specifically, the substrate 11 in the reinforcement structure for the COB module and the flexible circuit board 50 are bonded through the heterogeneous conductive adhesive layer 70 to form an electrical connection.

[0050] Specifically, the anisotropic conductive adhesive layer 70 has good adhesion and stable conductive performance, and can provide reliable electrical connection and signal transmission, while simplifying the manufacturing process and improving production efficiency.

[0051] In this embodiment, a label paper 80 is further included. The label paper 80 can be a label paper 80 with a QR code or a barcode. The label paper 80 is attached to the side of the flexible circuit board 50 facing away from the COB module 10 .

[0052] Third embodiment

[0053] Another embodiment of the present invention further provides an ADAS camera, which is different from the second embodiment in that the substrate 11 is an FPC board and the heat dissipation layer 30 is a steel plate.

[0054] Specifically, the FPC board usually adopts a flexible substrate, and adopting a steel plate as the heat dissipation layer 30 can enhance its rigidity.

[0055] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention are intended to be covered by the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A reinforcement structure for a COB module, wherein the COB module (10) comprises a substrate (11) and a sensor (12) electrically connected to the substrate (11), characterized in that: The invention comprises a heat-conducting adhesive layer (20) and a heat-dissipating layer (30), wherein the heat-conducting adhesive layer (20) and the heat-dissipating layer (30) are sequentially stacked on a side of a substrate (11) facing away from a sensor (12), and the heat-dissipating layer (30) is a silicon wafer, white glass or a steel plate, and is used for dissipating heat and reinforcing the COB module (10).

2. The reinforcement structure for a COB module according to claim 1, wherein: The heat-conducting adhesive layer (20) is a heat-conducting silver adhesive layer.

3. The reinforcement structure for COB module according to claim 1, wherein: The heat dissipation layer (30) has a thickness of 0.3 mm to 3 mm.

4. An ADAS camera, characterized in that: The invention comprises a lens assembly (40), a COB module (10), a flexible circuit board (50), and a reinforcement structure for a COB module according to any one of claims 1 to 3, wherein the lens assembly (40), the COB module (10), the reinforcement structure for a COB module, and the flexible circuit board (50) are stacked in sequence.

5. The ADAS camera according to claim 4, wherein: The lens assembly (40) comprises a lens (41) and a lens mount (42), wherein the lens (41) is fixed to the COB module (10) via the lens mount (42), thereby increasing the contact area between the COB module (10) and the lens (41).

6. The ADAS camera according to claim 4, wherein: The substrate (11) is a PCB board, and the heat dissipation layer (30) is a silicon wafer or white glass.

7. The ADAS camera according to claim 4, wherein: The substrate (11) is an FPC board, and the heat dissipation layer (30) is a steel plate.

8. The ADAS camera according to claim 4, wherein: It also includes an attachment layer (60), which is a heat-conducting silver glue layer and is used to attach the sensor (12) to the substrate (11).

9. The ADAS camera according to claim 5, wherein: The lens (41) and the lens mount (42) are connected via a first curing adhesive layer (43).

10. The ADAS camera according to claim 4, wherein: The reinforcing structure for the COB module is connected to the flexible circuit board (50) via a heterogeneous conductive adhesive layer (70).

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