Lighting Device Heat Dissipation via Air Circulation

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Solution Overview

Problem

The existing lighting devices for liquid crystal display panels in head-up displays face issues with heat accumulation, leading to deformation of the case body and reduced lighting quality due to the sealed space surrounding the light source unit.

Innovation Solution

The design incorporates a case body with heat releasing portions and air introducing features, allowing heat generated by the light sources to be released outside, preventing deformation and maintaining illumination quality by ensuring efficient air circulation within the cavity portion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the case body is arranged between the diffusing member and the substrate to form a sealed cavity portion, then the light beam can be uniformly directed to the liquid crystal display panel, but heat generated by the light source accumulates in the sealed space causing deformation of the case body and degradation of lighting quality

Engineering Contradiction:
Improvelighting qualityVSAvoidheat accumulation
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The patent extracts the harmful heat from the sealed cavity by introducing air through air introducing portions and enabling heat release through heat releasing portions. This separates the light transmission function (maintained by the sealed cavity structure) from the heat management function (achieved by the air circulation path), allowing the cavity to remain sealed for optical purposes while heat is actively removed through dedicated pathways.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Air acts as an intermediary substance in this patent. By introducing air into the cavity through air introducing portions and allowing it to circulate through heat releasing portions, the system uses air as a heat transfer medium to carry heat away from the light source without compromising the sealed structure needed for proper light beam uniformization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the cavity portion is sealed by the substrate and diffusing member, then the optical path is protected and light uniformization is achieved, but heat dissipation is prevented leading to case body deformation

Engineering Contradiction:
Improveoptical path stabilityVSAvoidstructural stability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent segments the cavity functions into two separate systems: the sealed optical cavity for light transmission and protection, and the air circulation system for heat management. The sealed cavity maintains optical path stability while the segmented air circulation pathways (through air introducing portions and heat releasing portions) handle thermal management, preventing case body deformation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different local qualities to different parts of the case body. The main cavity remains sealed to maintain optical path stability, while specific localized portions (air introducing portions and heat releasing portions) are designed with different properties to enable air circulation and heat dissipation. This localized modification allows heat management without compromising the overall sealed structure.

Inventive Principle:
Principle #3Local quality

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 solution effectively prevents deformation of the case body and diffusing member, ensuring consistent illumination quality by releasing heat generated during light emission, thus maintaining efficient light delivery to the liquid crystal display panel.

Implementation Method 1

a light source unit having a light source (LED) mounted (disposed) on a substrate as a circuit board

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 2

heat generated when the light source emits a light beam stays in the sealed space

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

heat generated when the light source emits a light beam

Methodology Applied
Scientific EffectThermal Radiation: Thermal Radiation

Data Source

PatentEP2518386B1Lighting device
Publication Date: 2021.02.17 NIPPON SEIKI CO LTD
  • EP2518386B1 patent drawingFigure 1~2
  • EP2518386B1 patent drawingFigure 3
  • EP2518386B1 patent drawingFigure 4

AI summary

Disclosed is a lighting device that prevents deformations in the casing, etc., thereof caused by heat being emitted when the light source is lit, thereby avoiding risk that the quality of illumination of a member being illuminated will deteriorate. The lighting device comprises a light source unit (23), whereupon light sources (22) are positioned upon a circuit substrate (21); an LCD panel (24) which is the member being illuminated by the light that is emitted from the light sources (22); a casing (27), further comprising a hollow portion (50) that is disposed so as to accommodate the light sources (22); and a diffusion member (25) that is installed upon the casing (27). The circuit substrate (21) is mounted so as to block the lower end aperture (51) of the hollow portion (50), and the diffusion member (25) is mounted so as to block the upper end aperture (52) of the hollow portion (50), which constitutes the opposite end of the hollow portion (50) from the lower end aperture (51) thereof. Radiation units (61d, 61f, 62d, 62f) are formed upon the casing (27) in order to radiate heat caused by the light sources (22) outside the casing (27).