Refractive Diffuser for Time-of-Flight Camera Irradiance Compensation
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Solution Overview
Problem
Conventional time-of-flight (TOF) 3D camera illumination systems are inefficient, leading to reduced irradiance with angular displacement, increasing costs and engineering difficulties due to heat dissipation issues, limiting the precision of applications that require threshold irradiance values.
Innovation Solution
A TOF 3D camera system utilizing a refractive diffuser with a varying intensity profile, characterized by intensity increasing with angular displacement, to compensate for irradiance decrease and reduce wasted light, thereby enhancing illumination efficiency and reducing heat dissipation needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a diffractive diffuser is used to distribute light across the camera field of view, then illumination of regions with greater angular displacement is improved, but light delivery efficiency decreases to less than 75%
Solution Approach 1:
The patent changes the fundamental parameter of light distribution by using a refractive diffuser instead of a diffractive diffuser. The refractive diffuser employs refraction rather than diffraction to distribute light, achieving superior light delivery efficiency of at least 95% while still providing the necessary illumination across the field of view with varying intensity profile.
Solution Approach 2:
The patent uses a varying intensity profile in the refractive diffuser that replicates the compensation function of diffractive diffusers but with improved efficiency. The varying intensity profile creates copies of the light distribution pattern needed to compensate for angular displacement effects while minimizing energy loss.
2Illumination intensity
If illumination intensity is increased to compensate for irradiance decrease with angular displacement, then objects at greater angular displacement are illuminated adequately, but heat dissipation requirements and costs increase
Solution Approach 1:
The patent changes the light distribution parameter through a varying intensity profile in the refractive diffuser, which compensates for angular displacement effects without requiring uniform high-intensity illumination across the entire field. This selective intensity distribution reduces overall power consumption and heat generation while maintaining adequate illumination where needed.
Solution Approach 2:
The varying intensity profile provides different illumination intensities at different locations in the field of view, matching the local requirements for compensation. Regions with greater angular displacement receive enhanced illumination while regions closer to the optical axis receive appropriate baseline illumination, optimizing overall system efficiency and reducing heat dissipation needs.
3Stability of the object's composition
If conventional illumination systems are used to compensate for irradiance decrease, then illumination homogeneity is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the collimation function and the varying intensity profile function into a single integrated optical system. The refractive diffuser is positioned to receive collimated light and simultaneously applies the varying intensity profile, combining multiple functions into one component and reducing overall system complexity compared to separate illumination compensation systems.
Solution Approach 2:
The varying intensity profile parameter in the refractive diffuser provides the necessary irradiance compensation for angular displacement effects. This single parameter change in the diffuser design achieves illumination homogeneity across the field of view without requiring complex multi-component illumination systems.
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 system achieves improved irradiance homogeneity across the camera field of view, increasing precision in distance measurements and reducing material costs and engineering complexity by delivering at least 95% of the source light to the field of view while minimizing heat dissipation requirements.
Implementation Method 1
a collimator configured to receive and collimate the source light to create collimated light
Implementation Method 2
A refractive diffuser is operable to be tuned to the camera field of view and configured to receive and diffuse the collimated light to create refracted light
Implementation Method 3
a light collector with a photosensitive surface configured to receive the return image light to be used for calculating a distance measurement of the object
Data Source
AI summary
A gaming system comprising a time-of-flight 3D camera and related method for illuminating a camera field of view and capturing return image light are disclosed herein. In one example, the time-of-flight 3D camera includes a light source configured to emit source light along an optical axis, and a collimator configured to receive and collimate the source light to create collimated light. A refractive diffuser is operable to be tuned to the camera field of view and configured to receive and diffuse the collimated light to create refracted light having a varying intensity profile. The refractive diffuser is further configured to guide the refracted light to illuminate only a portion of the camera field of view to reduce wasted source light.