Illumination Device Uniform Light Intensity Sensor
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Solution Overview
Problem
Light detection devices, such as time-of-flight devices, face challenges in achieving uniform light intensity across the image sensor, especially in wide field of view applications, leading to decreased signal-to-noise ratio (SNR) at image borders due to natural vignetting and intrinsic relative illumination loss, which affects performance in high background brightness conditions.
Innovation Solution
An illumination device with a light source and a light intensity adapting device that adjusts the light intensity profile to provide uniform light intensity on the image sensor, compensating for relative illumination loss and distortion, using a diffractive optical element and field of illumination adapting lenses to optimize light distribution based on the optical lens's field of view and virtual target area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wide field of view optical lens is used to capture a larger scene, then the coverage area is improved, but the light intensity becomes non-uniform with lower intensity at corners and borders
Solution Approach 1:
The illumination device applies different light intensities to different regions of the scene. Specifically, higher light intensity is directed toward corners and borders where the optical lens naturally captures less light, while lower intensity is applied to central regions. This compensates for the vignetting effect and achieves uniform light intensity distribution across the entire image sensor.
Solution Approach 2:
The illumination pattern intentionally uses an asymmetric intensity distribution that is inverted relative to the optical lens's natural response. Since the optical lens captures more light at the center and less at the corners, the illumination device applies more light to the corners and less to the center, creating a compensating asymmetric pattern that results in uniform overall illumination.
2Illumination intensity
If light intensity is increased at corners and borders to compensate for vignetting, then light intensity uniformity is improved, but power consumption increases
Solution Approach 1:
Instead of uniformly increasing light intensity across the entire scene, the illumination device applies excessive light intensity only to the specific regions (corners and borders) that suffer from vignetting. The central regions receive reduced or normal intensity. This partial application of increased intensity achieves the desired uniformity while minimizing overall power consumption compared to a uniform high-intensity approach.
3Use of energy by stationary object
If non-uniform illumination is accepted to reduce power consumption, then energy efficiency is improved, but signal-to-noise ratio decreases at image borders
Solution Approach 1:
The illumination device addresses the SNR issue by applying enhanced light intensity locally to the specific regions (corners and borders) where the optical lens captures insufficient light. This localized compensation ensures that the signal-to-noise ratio is maintained across the entire image sensor, preventing degradation in measurement precision at the borders while avoiding the need to uniformly increase power consumption.
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 solution enhances sunlight robustness, reduces power consumption, and facilitates image processing by maintaining consistent SNR across the image, allowing for effective monitoring of large scenes with reduced illumination gradient.
Implementation Method 1
using a diffractive optical element and field of illumination adapting lenses to optimize light distribution
Implementation Method 2
an optical lens portion configured to image light reflected from a scene onto the light detection sensor
Data Source
AI summary
An illumination device for a light detection device, the light detection device including a light detection sensor and an optical lens portion, wherein the illumination device includes a light source configured to emit light to a scene and a light intensity adapting device configured to adapt a light intensity profile of the light emitted by the light source for at least partially providing a uniform light intensity on the light detection sensor of light reflected from the scene and detected by the light detection sensor through the optical lens portion.