Laser Array Pre-Charge Modulation for Low-Power 3D Imaging
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Solution Overview
Problem
Existing distance scanning technologies, such as laser range finders, are often bulky and not suitable for integration into smaller hand-held devices like mobile phones, which require efficient power and processing management.
Innovation Solution
The development of a laser driver system that includes a pulse input for receiving logical pulse control signals, a delay circuit to generate delayed pulses, and control circuitry to selectively drive main and precharge pulse outputs, optimizing laser power management and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional laser range finder technology is used, then distance scanning capability is achieved, but device size and power consumption increase making it unsuitable for hand-held devices
Solution Approach 1:
The laser driver is segmented into multiple independent current sources (first current source, second current source, third current source) that can be selectively activated. This allows the system to divide the laser operation into distinct phases (pre-charge, main pulse, extended pulse) with optimized power consumption for each phase, enabling hand-held device integration while maintaining distance scanning capability
Solution Approach 2:
A pre-charge current is applied to the laser diode before the main measurement pulse. This preliminary action brings the laser diode closer to its threshold current, reducing the power required for the subsequent main pulse and enabling more efficient operation in power-constrained hand-held devices
2Use of energy by moving object
If laser current is reduced to save power, then power consumption decreases, but laser output intensity and measurement reliability deteriorate
Solution Approach 1:
The laser is driven with periodic pulsed signals rather than continuous current. The system uses a main pulse output for primary measurements and an extended pulse output for additional measurements when needed. This periodic operation allows the laser to return to a lower pre-charge current state between pulses, reducing average power consumption while maintaining peak output intensity during active measurement periods
3Measurement precision
If continuous laser operation is used, then measurement accuracy is maintained, but power consumption increases
Solution Approach 1:
The system switches from continuous laser operation to periodic pulsed operation. The laser is activated only when measurement is required (main pulse or extended pulse) and returns to a low-power pre-charge state otherwise. This maintains measurement precision when needed while dramatically reducing average power consumption for hand-held device operation
Solution Approach 2:
The system dynamically changes the laser drive current parameter between three distinct levels: pre-charge current (low power standby), main pulse current (full power measurement), and extended pulse current (extended duration measurement). This parameter switching enables the laser to maintain measurement accuracy when required while operating in a low-power state during idle periods
Data Source
AI summary
Laser drivers and methods are disclosed including a pulse input for receiving one or more logical pulse control signals, a delay circuit, a main pulse output, and a precharge pulse output for efficiently driving a laser with reduced time delay to desired optical output and reduced power consumption during between optical outputs.