Fisheye Camera Module NIR Diffusion for Uniform Illumination
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Solution Overview
Problem
Cameras with wide field of view, such as those using fisheye lenses, face challenges in uniformly illuminating their field of view due to directional light sources, which results in varying light intensity across the view area.
Innovation Solution
Incorporating a camera module with near-infrared (NIR) light emitting diodes (LEDs) and a light-diffusing structure, like microlenses, within a housing transparent to NIR but opaque to visible light, to spread out the light uniformly across the field of view, ensuring consistent illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If directional light sources are used to illuminate the field of view, then the light sources can be configured with specific intensity and direction, but the illumination becomes non-uniform across the wide field of view
Solution Approach 1:
The patent introduces a light diffuser as an intermediary component between the directional LED light sources and the wide field of view. The diffuser scatters the directional light into multiple directions, creating uniform illumination across the entire field of view while maintaining the benefits of using LED light sources.
Solution Approach 2:
The patent changes the directional parameters of light emission by using a diffuser that transforms the concentrated directional light from LEDs into omnidirectional or widely distributed light patterns. This parameter change enables the light to cover the wide field of view uniformly.
2Ease of operation
If multiple light sources are added to illuminate the wide field of view uniformly, then the illumination uniformity improves, but the device complexity increases
Solution Approach 1:
The light diffuser acts as a mediator that allows a single or few light sources to achieve the illumination effect that would otherwise require multiple light sources. The diffuser distributes the light from one source across the entire wide field of view, simplifying the device architecture.
Solution Approach 2:
The light diffuser serves multiple functions: it distributes light uniformly, maintains light intensity, and enables wide field of view coverage. This multi-functionality reduces the need for additional specialized components or multiple light sources.
3Area of stationary object
If the light sources are positioned to cover the entire field of view, then the illumination coverage improves, but the intensity distribution becomes non-uniform
Solution Approach 1:
The diffuser serves as an intermediary that decouples the relationship between light source position and illumination distribution. It takes light from positioned sources and redistributes it uniformly across the entire field of view, achieving both full coverage and uniform intensity.
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
The solution provides substantially uniform illumination throughout the field of view, enhancing image quality in low-light conditions by maintaining intensity variation below 20-50% across the entire view area.
Implementation Method 1
light-diffusing structures (e.g., microlenses) that spread out the light emitted by the light emitters to provide illumination that is substantially uniform throughout the field of view
Implementation Method 2
The portion of the housing is transparent to near infrared (NIR) light
Data Source
AI summary
A camera module includes a housing with an opening and a portion that surrounds the opening, wherein the portion of the housing is transparent to near infrared (NIR) light. A fisheye lens is disposed within the opening such that a portion of the fisheye lens protrudes through the opening. An image sensor is disposed within the housing and optically coupled to the fisheye lens. The image sensor is sensitive to visible light and NIR light. A plurality of NIR light emitters is disposed within the housing. The NIR light emitters are configured to emit NIR light through the NIR-transparent portion of the housing. The NIR-transparent portion of the housing may include a light-diffusing structure, such as a pattern of microlenses formed on an inner surface of the NIR-transparent portion of the housing, to spread out the NIR light emitted by the NIR light emitters.