Range Sensor Charge Generating Region Extension for Aperture Ratio
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Solution Overview
Problem
The existing Time-Of-Flight (TOF)-type range image sensors have a low aperture ratio and poor charge transfer efficiency due to the charge discharging region being disposed around the entire pixel region, which limits the area of the charge generating region and increases the distance charges need to travel to the charge collecting region.
Innovation Solution
The range sensor design extends the charge generating region to the sides of the polygonal pixel region except for the corner portions, incorporating a signal charge collecting region at the center and an unnecessary charge collecting region in the corners, with transfer and unnecessary charge collecting gate electrodes to improve aperture ratio and charge transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the charge discharging region is disposed around the entire pixel region, then the charge transfer efficiency is improved, but the aperture ratio is reduced
Solution Approach 1:
The charge collecting region is segmented into two distinct parts: a signal charge collecting region disposed inside the charge generating region, and an unnecessary charge collecting region disposed outside the charge generating region. This segmentation allows charges to be collected at different locations optimized for their respective purposes, resolving the contradiction between maintaining high aperture ratio and ensuring efficient charge transfer.
2Area of stationary object
If the charge generating region is enlarged to the end of the pixel region, then the aperture ratio is improved, but the charge transfer efficiency is reduced
Solution Approach 1:
The patent introduces a spatial dimension distinction by placing the signal charge collecting region inside the charge generating region while positioning the unnecessary charge collecting region outside. This dimensional arrangement allows the charge generating region to extend to the pixel region boundaries (improving aperture ratio) while maintaining efficient charge transfer paths to the internal signal charge collecting region.
3Area of stationary object
If the charge generating region extends to corner portions, then the aperture ratio is improved, but the transfer distance for charges increases
Solution Approach 1:
Different regions are assigned different qualities and functions: the signal charge collecting region inside the charge generating region handles efficient charge collection for signal pixels, while the unnecessary charge collecting region outside handles charges from non-signal areas. This local differentiation allows corner portions to be utilized for aperture ratio improvement without compromising charge transfer efficiency for signal charges.
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 aperture ratio and charge transfer efficiency, improving space resolution and reducing distance calculation deviations, while allowing for integrated pixel regions and efficient sensor area usage.
Implementation Method 1
a charge generating region configured such that outer peripheries thereof extend to sides of a polygonal pixel region except for corner portions of the pixel region and configured to generate charges in response to incident light
Implementation Method 2
a transfer electrode disposed between the signal charge collecting region and the charge generating region, and configured to cause the signal charges from the charge generating region to flow into the signal charge collecting region in response to an input signal
Implementation Method 3
an unnecessary charge collecting gate electrode disposed between the unnecessary charge collecting region and the charge generating region, and configured to cause the unnecessary charges from the charge generating region to flow into the unnecessary charge collecting region in response to an input signal
Data Source
AI summary
A range sensor includes a charge generating region, a signal charge collecting region, an unnecessary charge collecting region, a photogate electrode, a transfer electrode, and an unnecessary charge collecting gate electrode. Outer peripheries of the charge generating region extend to sides of a polygonal pixel region except for corner portions thereof. The signal charge collecting region is disposed at a center portion of the pixel region and inside the charge generating region so as to be surrounded by the charge generating region. The unnecessary charge collecting region is disposed in the corner portion of the pixel region and outside the charge generating region. The photogate electrode is disposed on the charge generating region. The transfer electrode is disposed between the signal charge collecting region and the charge generating region. The unnecessary charge collecting gate electrode is disposed between the unnecessary charge collecting region and the charge generating region.