Laser Light Source Device with Diffusion Member Detection

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Solution Overview

Problem

Existing image projection apparatuses using laser light sources lack adequate safety measures when the diffusion member deviates from or breaks within the optical path, leading to potential laser beam leakage and safety hazards, especially when it does not exist in the normal state or breaks due to external factors like falling.

Innovation Solution

Incorporating a detection system, such as capacitance, temperature, magnetic, or potential sensors, to monitor the diffusion member's presence and integrity, and a controller to stop the laser beam emission if deviations or abnormalities are detected, ensuring the laser beam is shielded and preventing leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a diffusion member is provided in the traveling optical path of the laser beam to relieve energy density, then laser beam safety is improved, but if the diffusion member deviates or breaks, laser beam leakage occurs and safety is reduced

Engineering Contradiction:
Improvelaser beam safetyVSAvoidlaser beam leakage hazard
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A detection element is positioned to detect the diffusion member before the laser beam reaches it. When the diffusion member is detected to be absent or abnormal, the system preliminarily activates a light-shielding member to block the optical path, preventing laser beam leakage before it can occur. This proactive approach ensures safety even when the diffusion member deviates or breaks.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A light-shielding member is introduced as an intermediary protective element in the optical path. When the detection element signals an abnormality in the diffusion member, the light-shielding member engages to block the laser beam, serving as a mediator that prevents direct exposure and ensures safety even when the primary diffusion member fails.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a detection element and light-shielding member system is added to detect diffusion member abnormalities, then laser beam safety is improved, but device complexity increases

Engineering Contradiction:
Improvelaser beam safetyVSAvoidsafety system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The safety function is extracted and separated into distinct modular components: a detection element positioned near the diffusion member, a control mechanism, and a light-shielding member. This modular extraction allows each component to perform its specific function independently, making the system easier to design, manufacture, and maintain while ensuring comprehensive safety coverage.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The safety system is segmented into functionally independent parts: the detection element that monitors the diffusion member, the control logic that processes detection signals, and the light-shielding member that executes the safety action. This segmentation reduces overall system complexity by allowing each segment to be optimized and implemented separately.

Inventive Principle:
Principle #1Segmentation

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

Enhances safety by immediately stopping the laser beam transmission when abnormalities in the diffusion member are detected, preventing accidental exposure and ensuring the beam does not leak outside the apparatus, thus improving human safety.

Implementation Method 1

a detection element disposed close to the diffusion member and configured to detect the diffusion member

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a detection element disposed close to the diffusion member and configured to detect the diffusion member

Methodology Applied
Scientific EffectTemperature: Temperature Gradient

Implementation Method 3

a detection element disposed close to the diffusion member and configured to detect the diffusion member

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 4

a detection element disposed close to the diffusion member and configured to detect the diffusion member

Methodology Applied
Scientific EffectElectric potential: Electric Field

Implementation Method 5

a laser light source configured to emit laser beam

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 6

a diffusion member provided in a traveling optical path of the laser beam such that laser beam with high output is not directly leaked

Methodology Applied
Scientific EffectScattering: Scattering

Data Source

PatentEP3121649B1Light source device and image projection device having light source device
Publication Date: 2019.12.18 RICOH CO LTD
  • EP3121649B1 patent drawingFigure 1
  • EP3121649B1 patent drawingFigure 2~4
  • EP3121649B1 patent drawingFigure 5~6

AI summary

A light source device capable of contributing to an improvement in safety to laser beam is provided, even if a situation that a diffusion member does not exist in a traveling optical path of the laser beam in a normal state occurs. The light source device of the present invention includes a light source section (1) that emits laser beam (P), a diffusion member (8) that is provided in a traveling optical path of the laser beam (P) and transmits the laser beam (P) while diffusing the laser beam, a detection element (20) that detects whether the diffusion member (8) exists in the traveling optical path of the laser beam in a normal state by a physical characteristic of the diffusion member (8) and outputs a state detecting signal, and an abnormal state determiner (30a) that has a predetermined threshold to determine whether the diffusion member exists in the traveling optical path in a normal state and determines an abnormal state of the diffusion member (8) by comparing the state detecting signal with the threshold. The light source section (1) is controlled in a direction where an output of the laser beam (P) is reduced when the abnormal state is determined by the abnormal state determiner (30a).