Sinusoidal Laser Scanner Optical Filter Brightness Compensation

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Solution Overview

Problem

Scanning laser projectors experience brightness variations due to sinusoidal scanning, which can be costly to address with increased resolution of analog-to-digital converters.

Innovation Solution

Incorporating an optical filter with variable attenuation characteristics to compensate for brightness variations, reducing the need for additional data bits in digital-to-analog converters and allowing operation with single-bit or binary drivers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If increased resolution of analog-to-digital converters is used to combat brightness variations, then brightness uniformity is improved, but cost increases

Engineering Contradiction:

Improvebrightness uniformityVSAvoidcost

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

An optical filter is introduced as an intermediary component between the laser scanner and the display medium. The filter compensates for brightness variations caused by sinusoidal scanning without requiring higher resolution analog-to-digital converters, thus maintaining cost-effectiveness while achieving uniform brightness across the raster pattern.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The optical filter modifies the intensity distribution parameter of the laser beam dynamically to counteract the brightness variations inherent in sinusoidal scanning. By changing the filter's attenuation characteristics, the system achieves uniform brightness without increasing converter resolution.

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If higher resolution analog-to-digital converters are used, then brightness variations are reduced, but the number of data bits required increases

Engineering Contradiction:

Improvebrightness uniformityVSAvoidnumber of data bits

Core Design Contradiction:

Illumination intensityVSLoss of information

Solution Approach 1:

The optical filter serves as a mediator that handles the brightness compensation function, allowing the system to operate with single-bit or binary drivers. This eliminates the need for additional data bits that would otherwise be required to compensate for brightness variations through higher resolution converters.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the electronic approach (higher resolution converters) with an optical approach (optical filter). This substitution allows the system to achieve brightness uniformity without increasing the data bit resolution, effectively replacing an electronic solution with an optical one.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The optical filter ensures uniform brightness across the raster pattern, reducing the required number of data bits and lowering costs while maintaining image quality.

Implementation Method 1

an optical filter with variable attenuation characteristics to compensate for brightness variations

Methodology Applied

Scientific EffectOptical filter attenuation: Filter (optical)

Data Source

PatentUS8717342B2Sinusoidal laser scanner with optical filter

Publication Date: 2014.05.06 MICROVISION INC

AI summary

A scanning projector includes an optical filter. The optical filter exhibits a variable attenuation as a function of position. The scanning projector may scan sinusoidally in at least one dimension. The variable attenuation of the optical filter compensates for brightness variations due to sinusoidal scanning.