Laser Array Capacitor Layout for Faster ToF Light Emission
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Solution Overview
Problem
Existing light-emitting devices for three-dimensional shape measurement using the Time of Flight (ToF) method face challenges in achieving a short rise time of light emission due to high effective inductance in the electric current path, which affects the accuracy and efficiency of light emission.
Innovation Solution
The device incorporates a laser element array with a pair of capacitors disposed beside two sides to sandwich the array and a driving unit on another side, reducing the effective inductance of the electric current path for faster light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional light-emitting device configuration is used, then the device structure is simple, but the effective inductance of the electric current path is high, resulting in long rise time of light emission
Solution Approach 1:
The patent applies dimensionality change by transitioning from a planar two-dimensional layout to a three-dimensional stacked configuration. The laser element array, capacitors, and driving unit are arranged in vertical layers rather than spread out in a plane. This spatial reorganization shortens the electric current path length while maintaining a compact footprint, thereby reducing effective inductance and achieving faster light emission rise time without proportionally increasing device area.
Solution Approach 2:
The patent implements nesting by placing the driving unit and capacitors in close proximity to the laser element array, with capacitors positioned on opposite sides of the array and the driving unit adjacent to another side. This nested arrangement creates a compact integrated structure where components are tightly coupled, minimizing the loop area of the electric current path and reducing effective inductance, thus enabling shorter rise time of light emission.
2Loss of time
If the effective inductance is reduced by repositioning components, then the rise time of light emission is shortened, but the layout complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the device into distinct functional layers: the laser element array layer, the capacitor layer positioned on opposite sides, and the driving unit layer. This segmentation allows each component to be optimized independently for its specific function while maintaining short interconnection paths. The modular layered structure reduces the electric current path length and effective inductance, achieving shorter rise time without excessive layout complexity.
3Speed
If capacitors are disposed beside two sides of the laser element array, then the effective inductance is reduced, but the device area increases
Solution Approach 1:
The patent resolves the area conflict by moving from a two-dimensional planar expansion to a three-dimensional stacked architecture. Capacitors are positioned vertically adjacent to the laser element array rather than extending the device footprint horizontally. This vertical arrangement reduces the electric current path length and effective inductance for faster rise time while maintaining a compact device area, as the increased component density is achieved through the third dimension.
Data Source
AI summary
A light-emitting device includes a laser element array having a quadrangular planar shape, a pair of capacitors that supply an electric current for light emission of the laser element array, and a driving unit that drives the laser element array by turning on and off the electric current for light emission of the laser element array. The pair of capacitors are disposed beside two sides of the laser element array that face each other so as to sandwich the laser element array, and the driving unit is disposed beside another side of the laser element array.