Abstract

Integrating camera modules into electromechanical systems, such as smart glasses, mobile phones, and telecommunications hardware, frequently risks perturbing the delicate lens-to-sensor pose and degrading optical performance. Conventional assembly techniques that rely on mechanical fasteners (e.g., screws) or glued secondary brackets introduce structural distortion due to mechanical tolerance mismatches, improper installation torque, or excessive bracket stiffness. Furthermore, during sensor and voice coil motor operation, adjacent components generate heat and may undergo differential thermal expansion because of mismatched coefficients of thermal expansion. This differential expansion can cause the sensor plane to shift in position or orientation, introducing thermal drift in module intrinsics, inducing sensor bowing, and degrading image focus and sharpness across the field of view.

The disclosed technology describes a camera module integration system that eliminates secondary brackets by bonding the rear face of a camera module stiffener to a system substrate using an adhesive layer. Alignment is established through a pin-and-slot arrangement, where alignment pins on the substrate engage a corner opening and an axis-aligned corner slot on the back of the camera module. The adhesive layer, which may be a pressure sensitive adhesive (PSA) or liquid dispensed adhesive (LDA) cured by ultraviolet light or heat, functions as a viscoelastic buffer between the module stiffener and the substrate. To balance bond strength, thermal transfer, and shear coupling, the adhesive layer can be configured in various thicknesses (e.g., 50 to 200 microns) and different geometric topologies, including solid rectangles, central dots, perimeter frames, or radially-aligned spokes, with or without a mesh carrier. Furthermore, the adhesive layer can be doped with certain materials such as ceramic, carbon-based materials or metallic fillers to enhance thermal conductivity.

Thermal mitigation is achieved by directly sinking heat from the rear surface of the camera module stiffener into a larger metal substrate with sufficient thermal mass and surface area, reducing operational sensor temperatures and temperature-induced image noise. During thermal cycling, the viscoelastic properties of the adhesive layer absorb differential thermal expansion between the stiffener and the substrate, preventing mechanical strain from being transmitted to the sensor plane. By reducing fastener-induced assembly stresses and accommodating coefficients of thermal expansion mismatches, this architecture can maintain the as-assembled optical calibration, prevent sensor bowing, and preserve module focus and intrinsic accuracy across various operating temperature ranges.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Download

Share

COinS