Folded Prism Camera Module Layout for Compact Autofocus
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Solution Overview
Problem
Consumer electronics devices face a challenge in reducing camera size while maintaining or improving optical performance, as traditional optical systems become more complex with shrinking device sizes.
Innovation Solution
Incorporation of prisms in camera modules that fold light along additional axes using total internal reflection, with opaque masks to control stray light, and actuators for autofocusing capabilities, allowing the lens assembly and image sensor to be positioned adjacent to a common prism surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional optical systems are used to maintain camera performance, then optical quality is preserved, but device size increases
Solution Approach 1:
The patent employs a folding optical system using a prism to redirect light at non-traditional angles (e.g., 45-degree reflections), effectively folding the optical path into three-dimensional space. This allows the optical path length to be extended without increasing the linear footprint of the camera module, resolving the contradiction between maintaining optical performance and reducing device size.
Solution Approach 2:
The patent integrates multiple optical components (lens assembly, prism, image sensor) into a compact nested arrangement where the prism is positioned between the lens and sensor, and opaque masks are embedded within the prism structure. This nesting allows components to share space efficiently, reducing overall camera module volume while maintaining functional performance.
2Volume of moving object
If folding optics are used to reduce camera footprint, then device size decreases, but optical path complexity increases
Solution Approach 1:
The patent combines multiple functions into the prism component: it serves as both the light-folding element and the mounting structure for opaque masks. The opaque masks themselves perform multiple functions by simultaneously blocking stray light and defining the optical aperture. This merging reduces the number of separate components needed, simplifying the overall optical system despite the folded path.
Solution Approach 2:
The patent introduces opaque masks as intermediary elements within the optical path to manage stray light that results from the folded configuration. These masks act as mediators that control light distribution without requiring complex coating or alignment adjustments on the prism surfaces themselves, simplifying the implementation of the folding optics.
3Reliability
If prism with opaque masks is used to control stray light, then image quality improves, but manufacturing complexity increases
Solution Approach 1:
The patent divides the opaque masking function into multiple discrete masks positioned at different locations within the prism. Each mask can be manufactured and positioned independently, allowing for modular manufacturing approaches. This segmentation makes it easier to control the precision requirements for each individual mask rather than requiring a single complex mask structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces camera module size without compromising focal length or performance, enabling autofocusing and optical image stabilization with a reduced footprint.
Implementation Method 1
Inclined surfaces of the housing may be configured to reflect light traveling through the prism using total internal reflection
Implementation Method 2
The prism may include one or more opaque masks configured to block stray light within the prism to reduce flare
Data Source
AI summary
Embodiments described herein relate to camera modules which include a prism, and a lens assembly and image sensor positioned adjacent to a common side of the prism. The camera module may be configured such that the light enters the prism (e.g., from the lens assembly) via a first surface and exits the prism (e.g., directed to the image sensor) via the same, first surface. The prism may be operable to move with respect to both the lens assembly and the image sensor via an actuator. The prism may include opaque masks extending from a second surface that is opposite the first surface and into the body of the prism. The structure described can help reduce the overall package size of the camera module due to the configuration of the prism.