Periscope Camera Optical System IR Filter Placement
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Solution Overview
Problem
Conventional camera modules, especially periscope cameras, face issues with infrared light reaching the image sensor due to the inherent infrared transmittance of optical components, leading to color and brightness distortions, and require thin IR blocking filters that are difficult to produce and maintain mechanical stability.
Innovation Solution
An optical system for a camera module that includes an image sensor and an optical arrangement with a sequence of components such as prisms and planar optical elements, where at least one component acts as an absorption filter, allowing for a longer optical path and improved signal-to-noise ratio by placing the filter further away from the sensor, enabling thicker filter components that optimize blocking and transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin IR blocking filter is placed directly in front of the sensor, then the filter effect is sufficient, but the mechanical stability is low and production is difficult
Solution Approach 1:
The patent moves the IR blocking filter from a position directly in front of the sensor (2D plane) to a position within the optical path at a distance, utilizing the third dimension (depth/optical path length). This allows the filter to be integrated into a thicker optical component, providing both sufficient filter effect and mechanical stability.
Solution Approach 2:
The patent introduces an intermediary optical component (such as a lens or prism) that serves as a carrier for the IR blocking filter. This intermediary element allows the filter to be positioned at a distance from the sensor while still maintaining its function, thereby achieving both adequate filter performance and structural stability.
2Reliability
If a thin IR blocking filter is placed directly in front of the sensor, then the filter effect is sufficient, but the production cost increases and optical problems occur
Solution Approach 1:
The patent merges the IR blocking filter function with an existing optical component in the path (such as combining the filter with a lens or prism). This integration eliminates the need for a separate thin filter element, reducing production complexity and cost while maintaining effective IR blocking.
Solution Approach 2:
The patent makes an existing optical component multi-functional by integrating the IR blocking filter into it. This single component then serves both its primary optical function (focusing or deflecting light) and the secondary function of IR blocking, thereby reducing overall system complexity and production costs.
3Measurement precision
If the filter is placed further away from the sensor, then the optical path length increases and signal-to-noise ratio improves, but the component thickness increases
Solution Approach 1:
The patent utilizes the optical path dimension to achieve longer effective filter thickness without increasing the physical footprint in the direction of light travel. By positioning the filter within an angled optical path (using prisms or lens geometries), the effective path length through the filter material is increased while maintaining compact overall dimensions.
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 eliminates the need for thin filters directly in front of the sensor, enhancing the signal-to-noise ratio and mechanical stability while reducing production costs and optical problems, resulting in improved image quality.
Implementation Method 1
at least one of the components (a), (b), (d), and (e) includes at least one absorption filter
Implementation Method 2
Suitable blocking filters have a high degree of transmittance in a first wavelength range (transmission range), for example from 430 to approximately 650 nm
Implementation Method 3
a first prism, which deflects the incident light by 90°
Data Source
AI summary
An optical system for a camera module includes: an image sensor; and an optical arrangement defining a beam path, the optical arrangement including a plurality of optical components including a first prism and an optical lens system, the plurality of optical components being arranged in the beam path in a sequential order relative to one another and in front of the image sensor, the sequential order being such that the first prism is positioned before the optical lens system, at least one of the plurality of optical components including at least one absorption filter.