Camera module providing reliable long term adherence

An camera module includes a substrate, an image sensor chip, and a lens module. The image sensor chip is disposed on and electrically connected to the substrate. The lens module is mounted on the base via an adhesive layer. The lens module includes a bottom surface contacting with the substrate. The bottom surface defines at least one sloped surfaces thereon. At least one gap is defined between the substrate and the at least one sloped surface. The adhesive layer is disposed between the bottom surface and the substrate, the gap is capable of accepting adhesive when the lens module and substrate are pressed together.

BACKGROUND

1. Technical Field

The disclosure relates to a camera module.

2. Description of the Related Art

Current camera modules typically include an image sensor chip, a substrate, a number of gold wires, an encapsulation glass, and a lens module. The image sensor chip is disposed on the substrate and electrically connected to the substrate via the gold wires. The encapsulation glass encapsulates the image sensor chip and the gold wires. The lens module is installed on the substrate via adhesive layer, enclosing the image sensor chip, the gold wires, and the encapsulation glass. The problem is, during installing the lens module to the substrate, the adhesive layer is pressed and it spreads to the immediate area of the lens module on the substrate, contaminating the substrate. In addition, the adhered area of the lens module is limited to the bottom surface thereof, which is typically not adequate to provide reliable long term adherence.

What is desired is a camera module that can overcome the above-described problems.

DETAILED DESCRIPTION

Embodiments of the present camera module will now be described in detail with references to the drawings.

Referring toFIG. 1, a camera module100, according to a first exemplary embodiment, includes an image sensor chip10, a substrate20, an adhesive layer30, a number of conductive wires35, a lens module40, and a transparent cover50.

The image sensor chip10can be a charged coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS). The image sensor chip10includes a top surface11and a bottom surface13facing away from the top surface11. The image sensor chip10has a photosensitive area12formed on the center of the top surface11, and a non-photosensitive area14surrounding the photosensitive area12. The non-photosensitive area14has a number of chip pads101formed thereon.

The substrate20can be made of a material such as: polyimide, ceramic, or glass fiber. The substrate20has a supporting surface22. The bottom surface13of the image sensor chip10is adhered to the supporting surface22via the adhesive layer30. The adhesive layer30can be made, for example, from silicone, epoxy, acrylic, or polyamide.

A number of base pads201are disposed on the supporting surface22of the substrate20. Each base pad201can be electrically connected to a corresponding chip pad101via a conductive wire35. The conductive wires35can be made of a conductive material, such as gold, silver, aluminum, or an alloy thereof.

Alternatively, the image sensor chip10may be mechanically and electrically connected to the substrate20by available package processes, such as, chip-scale, wafer-level chip-scale, ceramic leaded, plastic leadless chip, thermal compression bonding, and flip chip packaging processes.

The lens module40is aligned with the image sensor chip10. The lens module40includes a lens barrel42, a lens holder44, and lens group46. The lens holder44comprises a top hollow cylinder441, a bottom hollow cylinder442coaxially aligned with and communicated with the top hollow cylinder441, and a connecting plate443connecting the top hollow cylinder441and the bottom hollow cylinder442. The lens group46is received in the lens barrel42. The combined lens barrel42and lens group46are received in the top hollow cylinder441. The image sensor chip10is received in the bottom hollow cylinder442. The bottom hollow cylinder442comprises a bottom surface445contacting with the substrate20, and an outer sidewall446. The bottom surface445defines a sloped surface4421extending from the bottom surface445to the outer sidewall446. The bottom surface445and the sloped surface4421define an angle therebetween. The angle, in this embodiment, is greater than 30 degrees. A gap4422is defined between the substrate20and the sloped surface4421of the bottom hollow cylinder442of the lens holder44.

The gap4422is filled with the adhesive layer30. The lens module40is disposed on the supporting surface22of the substrate20via the adhesive layer30.

The lens barrel42comprises a lower surface422facing the image sensor chip10. The transparent cover50, such as an infrared filter, is provided between the image sensor chip10and the lens group46and is configured for protecting the photosensitive area12from contamination and filtering light from the lens group46. The transparent cover50is secured to the lower surface422of the lens barrel42by the adhesive layer30. Alternatively, the transparent cover50may be directly fixed to the lens module40. Alternatively, the transparent cover50can be fixed to the inner surface of the connecting plate443. The transparent cover50may be an optical glass plate.

In assembly, the adhesive30is disposed on the supporting surface22of the substrate20, when the lens module40is assembled on the substrate20, the adhesive layer30flows into the gap4422of the lens holder44and contacts with the sloped surface4421, which prevents the adhesive layer30from overflowing on to the substrate30. In addition, the contact area between the adhesive layer30and the bottom surface445of the lens holder44may have complimentary patterns formed therein to increase contact area, thereby, bonding strength between the lens module40and the substrate20is stronger.

Referring toFIG. 2, a camera module200in accordance with a second exemplary embodiment is disclosed, differing from the camera module100only in the lens holder64. In this embodiment, the bottom hollow cylinder642comprises an inner sidewall647facing away the outer sidewall646. The bottom surface645defines an sloped surface6441extending from the bottom surface645to the inner sidewall647. The bottom surface645and the sloped surface6441defines an angle therebetween, which in this embodiment, is greater than 30 degree. A gap6442is defined between the substrate70and the sloped surface6441of the bottom hollow cylinder642of the lens holder64. In this embodiment, the gap6442is triangular in shape.

Referring toFIG. 3, a camera module300in accordance with a third exemplary embodiment is disclosed. In this embodiment, the profile of the bottom surface945of the lens holder94is “V” shaped but is not limited in that configuration. The bottom surface945is square shaped, and defines an inner sloped surface951extending from the bottom surface945to the inner sidewall941, and an outer sloped surfaces952extending from the bottom surface945to the outer sidewall942. A first gap97is defined between the substrate96and the inner sloped surface951. A second gap98is defined between the substrate96and the outer sloped surface952. It should note that, the bottom surface945of the lens holder94can also define a trapeziform gap for accommodating the adhesive layer95. Because the profile of the bottom surface945is “V” shaped, when the adhesive layer95disposes between the bottom surface945and the substrate96, which not only prevents the adhesive layer95from overflowing on to the substrate96, but also increases the amount of surface contact between the substrate96and the bottom surface945via the adhesive95.

It will be understood that the above particular embodiments and methods are shown and described by way of illustration only. The principles and the features of the disclosure may be employed in various and numerous embodiment thereof without departing from the scope of the invention as claimed. The above-described embodiments illustrate the scope of the invention but do not restrict the scope of the invention.