Retinal Scanning Display Laser Current Control
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Solution Overview
Problem
Retinal scanning type display apparatuses using low output lasers face insufficient current value adjustment resolution due to the lack of dedicated drive ICs, leading to limited current adjustment capabilities when using drive ICs designed for standard output lasers.
Innovation Solution
Incorporating a shunting element connected in parallel with the low output laser and utilizing a drive circuit capable of adjusting current values on a discrete basis within a higher operational current range, similar to that of standard output lasers, to enhance current value adjustment resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a low output laser is used in combination with a drive IC designed for standard output lasers, then the device complexity is reduced, but the current value adjustment resolution deteriorates
Solution Approach 1:
The drive circuit is segmented into two independent current control paths: a first current control circuit for controlling the laser diode current, and a second current control circuit for controlling the shunting element current. This segmentation allows each circuit to be optimized independently, enabling high-resolution current control for the laser while using a standard drive IC architecture.
Solution Approach 2:
A shunting element is introduced as an intermediary component connected in parallel with the laser diode. This shunting element acts as a current divider, allowing the drive circuit to control the laser current with high resolution by controlling the shunting element current, while the overall drive IC architecture remains standard and simple.
2Measurement precision
If a dedicated drive IC for low output laser is used, then the current value adjustment resolution is improved, but the device complexity increases
Solution Approach 1:
The drive IC is designed with multi-functionality to accommodate both standard output lasers and low output lasers. By incorporating a shunting element control function in addition to the standard laser drive function, the same drive IC architecture can achieve high-resolution current control for low output lasers without requiring a completely different dedicated IC design.
3Object-affected harmful factors
If the operational current range is reduced for low output laser, then the safety is improved, but the current adjustment resolution deteriorates
Solution Approach 1:
The system dynamically controls the shunting element current based on the desired laser output level. By dynamically adjusting the shunting element current in conjunction with the laser diode current, the system achieves fine-grained control over the laser output within the safe low current range, effectively improving current adjustment resolution without compromising safety.
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 improves the current value adjustment resolution for low output lasers in retinal scanning type display apparatuses, allowing for more precise control and stable image projection without relying on dedicated drive ICs, thereby maintaining image quality and accuracy.
Implementation Method 1
a shunting element (212R) that is connected in parallel with the low output laser (211R)
Data Source
AI summary
A display apparatus is provided. The display apparatus is a retinal scanning type display apparatus, and includes a low output laser whose operational current is less than that of a standard output laser; a shunting element that is connected in parallel with the low output laser; and a drive circuit that supplies a current to the low output laser and the shunting element. The drive circuit is a drive circuit for the standard output laser capable of adjusting a current value on a discrete basis in a range of an operational current that is higher than the operational current of the low output laser.