3D Image Sensor LC Resonator Power Optimization

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Solution Overview

Problem

Existing 3D image sensor modules face challenges in reducing power consumption while generating accurate depth information, as they often require high energy for modulating light and compensating for distortions in the oscillation frequency used for depth calculation.

Innovation Solution

A 3D image sensor module is designed with a distortion-compensated oscillation frequency generated by a differential LC voltage-controlled oscillator, which supplies a driving voltage to an optical shutter to modulate light into multiple phase signals, and an energy supplement system to reduce power consumption and prevent negative voltage swings, along with a burst mode driver to optimize energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a conventional oscillator is used to generate driving voltage for light modulation, then the system can operate, but power consumption is high and distortion compensation is complex

Engineering Contradiction:
Improvepower consumptionVSAvoiddepth information accuracy
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent employs an LC resonator that utilizes electromagnetic resonance to generate the driving voltage for the optical shutter. The resonant oscillation between the inductor and capacitor naturally produces the required sinusoidal waveform, eliminating the need for complex active oscillation circuits and reducing power consumption while maintaining signal accuracy for depth measurement

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The LC resonator is designed to self-oscillate at its natural resonant frequency, requiring minimal external energy input. The system automatically maintains the oscillation through energy exchange between the inductor and capacitor, with only small amounts of energy needed to compensate for resistive losses, thereby achieving low power consumption without sacrificing measurement precision

Inventive Principle:
Principle #25Self-service

2Stability of the object's composition

If energy is continuously supplied to the resonator, then oscillation is maintained, but power consumption increases

Engineering Contradiction:
Improveoscillation stabilityVSAvoidpower consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The energy supplementer is designed to provide energy to the LC resonator in periodic pulses synchronized with the oscillation cycle, rather than continuous energy supply. This allows the resonator to naturally oscillate between energy storage states, maintaining stable oscillation while minimizing the total energy input required from the power source

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system incorporates a feedback mechanism where the oscillation state of the LC resonator is monitored and used to control the timing and amount of energy supplementation. This ensures that energy is supplied only when needed to maintain oscillation amplitude, preventing energy waste while ensuring oscillation stability

Inventive Principle:
Principle #23Feedback

3Illumination intensity

If the optical shutter modulates light with high amplitude, then signal strength is sufficient, but distortion in driving voltage increases

Engineering Contradiction:
Improvelight modulation strengthVSAvoiddriving voltage accuracy
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent optimizes the operating parameters of the LC resonator, specifically the inductance and capacitance values, to achieve maximum oscillation amplitude at the resonant frequency. This natural amplification effect provides sufficient driving voltage for strong light modulation without requiring additional amplification stages that would introduce distortion

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

By utilizing the resonant vibration of the LC circuit, the system achieves maximum energy transfer and voltage amplitude at the resonant frequency. This resonant amplification provides the necessary driving strength for the optical shutter while maintaining sinusoidal waveform purity, avoiding the distortion that would result from non-resonant oscillation or active amplification

Inventive Principle:
Principle #18Mechanical vibration

Data Source

PatentEP3021138B1Depth sensing method and 3D image sensor
Publication Date: 2019.06.19 SAMSUNG ELECTRONICS CO LTD
  • EP3021138B1 patent drawingFigure 1
  • EP3021138B1 patent drawingFigure 2
  • EP3021138B1 patent drawingFigure 3

AI summary

A three-dimensional (3D) image sensor module including: an oscillator configured to output a distortion-compensated oscillation frequency as a driving voltage of a sine wave biased with a bias voltage; an optical shutter configured to vary transmittance of reflective light reflected from a subject, according to the driving voltage, and to modulate the reflective light into at least two optical modulation signals having different phases; and an image generator configured to generate image data about the subject, the image data including depth information that is calculated based on a difference between the phases of the at least two optical modulation signals.