ToF Light Emitter Layout for Uniform Reflection in 3D Sensing
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Solution Overview
Problem
In three-dimensional measurement using a ToF sensor, variations in reflection light amounts from a target object lead to decreased accuracy due to unequal irradiation light amounts from light emitting elements, causing differences in reflection light amounts between inner and outer portions, which affects the precision of the measurement.
Innovation Solution
A light emitting apparatus with regions of light emitting elements on a substrate, where the irradiation light amounts are controlled to create differences, particularly making the outer portions brighter than inner portions to equalize reflection light amounts, using drivers to adjust driving current and region arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If irradiation light amounts from all light emitting elements are made substantially equal, then the light emitting apparatus structure is simple and easy to control, but the reflection light amount received by the sensor varies between inner and outer portions, decreasing three-dimensional measurement accuracy
Solution Approach 1:
The patent applies local quality by making the irradiation light amount differ according to the spatial position of light emitting elements. Specifically, light emitting elements in outer regions (first regions at ends in arrangement direction) emit larger amounts of light, while elements in inner regions (second regions not at ends) emit smaller amounts. This localized differentiation compensates for the geometric effect where outer sensor elements receive less reflected light, thereby equalizing the reflection light amounts across all sensor elements and improving three-dimensional measurement accuracy.
2Measurement precision
If irradiation light amounts from outer regions are increased to compensate for lower reflection light amounts, then measurement accuracy improves, but the light emitting apparatus requires complex control mechanisms to adjust individual region light amounts
Solution Approach 1:
The patent segments the light emitting element array into multiple regions based on their positions in the arrangement direction. At least one first region is defined at an end in the arrangement direction, while at least one second region is defined not at an end. This segmentation allows independent control of irradiation light amounts for different regions, with outer regions emitting larger amounts and inner regions emitting smaller amounts, thereby achieving uniform reflection light amounts across the sensor while maintaining manageable control complexity through region-based grouping.
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 enhances the accuracy of three-dimensional measurements by equalizing reflection light amounts, ensuring precise determination of the target object's shape.
Implementation Method 1
light emitting elements including at least one light emitting element that is provided, on the substrate, in each region of plural regions and that emits irradiation light toward a target object
Data Source
AI summary
A light emitting apparatus includes a substrate and light emitting elements including at least one light emitting element that is provided, on the substrate, in each region of plural regions and that emits irradiation light toward a target object, the regions including a first region and a second region and being isolated from each other to be arranged one-dimensionally or two-dimensionally. In the plural regions, an irradiation light amount of at least one light emitting element provided in the first region that is a region located at an end in an arrangement direction is larger than an irradiation light amount of at least one light emitting element provided in the second region that is a region located at a place other than the end in the arrangement direction.