Light Projection Device with Multi-Portion Source and Scanning Mirror

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Solution Overview

Problem

Conventional light projection devices with optical scanners experience significant variations in light intensity across the scanning region due to the vibration of the scanning mirror, leading to uneven illumination.

Innovation Solution

A light projection device with multiple side-by-side light emission portions and an optical scanner that adjusts the mirror's swing angle to position intensity peaks within valley regions, ensuring consistent light distribution without reducing the maximum light output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If light is scanned by a single scanning mirror, then the light projection device is simple in structure, but the light intensity varies significantly across the scanning region

Engineering Contradiction:
Improvestructure simplicityVSAvoidlight intensity uniformity
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The patent divides the light source into multiple emission portions arranged side by side in the scanning direction. Each emission portion generates light that is scanned by the mirror to form a scanning light beam. By segmenting the light source and strategically positioning multiple emission portions, the patent creates overlapping intensity distributions that compensate for the natural intensity variations caused by mirror vibration, thus achieving more uniform illumination without complicating the overall device structure.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the mirror scans light from multiple light emission portions, then the illumination coverage is improved, but the intensity variation between peak and valley regions increases

Engineering Contradiction:
Improveillumination coverageVSAvoidintensity variation
Core Design Contradiction:
Area of stationary objectVSIllumination intensity

Solution Approach 1:

The patent applies local quality by creating specific intensity distribution characteristics for each scanning light from different emission portions. The mirror is positioned and angled such that each emission portion produces a scanning light with a characteristic intensity profile featuring peaks and valleys. By carefully controlling the local intensity characteristics of individual scanning lights and their spatial arrangement, the patent ensures that when these lights overlap in the illumination region, their combined intensity distribution achieves uniformity across the entire coverage area.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent merges multiple scanning lights from different emission portions in the illumination region. The light projection device generates several scanning lights simultaneously, each from a different emission portion, and these scanning lights are designed to overlap in the target illumination area. By combining these multiple scanning lights with carefully controlled intensity distributions, the patent achieves both wide illumination coverage and uniform intensity across the entire region.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If the mirror vibration speed is maximized in the central scanning region, then the scanning efficiency is improved, but the light intensity at ends becomes significantly lower

Engineering Contradiction:
Improvescanning efficiencyVSAvoidlight intensity at ends
Core Design Contradiction:
ProductivityVSIllumination intensity

Solution Approach 1:

The patent utilizes the periodic nature of mirror vibration to create periodic intensity distributions in the scanning light. The mirror oscillates back and forth at a determined frequency, creating regular patterns of peaks and valleys in the intensity distribution of each scanning light. By arranging multiple emission portions and their corresponding scanning lights with appropriate spatial relationships, the patent ensures that the periodic intensity variations from different scanning lights complement each other, filling in the low-intensity regions while maintaining high scanning efficiency through the continuous periodic motion of the mirror.

Inventive Principle:
Principle #19Periodic action

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 effectively reduces light intensity variations across the scanning region, maintaining high utilization efficiency and ensuring uniform illumination.

Implementation Method 1

an optical scanner having a mirror portion which scans light passed through the projection lens in a direction that the plurality of light emission portions is aligned

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

a vibration speed of the mirror is the fastest in a central part of a scanning range

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Data Source

PatentEP3904943A1Light projection device and light projection device for moving body
Publication Date: 2021.11.03 FUNAI ELECTRIC CO LTD
  • EP3904943A1 patent drawingFigure 1
  • EP3904943A1 patent drawingFigure 2
  • EP3904943A1 patent drawingFigure 3~4

AI summary

A light projection device (100) includes: a light source (1) having plural light emission portions (10) arranged side by side in a predetermined direction; a projection lens (2); and an optical scanner having a mirror portion (3a) which scans light passed through the projection lens in a direction that the light emission portions are aligned, and a drive source (3b) swinging the mirror portion. The mirror portion scans a scanning light, which is irradiated from each light emission portion and scanned by the mirror portion, to form an intensity distribution having a central valley part (41) and peaks (42, 43) located on both sides of the valley part. The optical scanner scans the light irradiated from the light emission portions in a manner that at least a peak of an intensity distribution of scanning light of other light emission portion is located in the valley part of the intensity distribution.