Illuminating Device With Hollow Optical Element

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Solution Overview

Problem

Conventional illuminating devices using surface light sources, such as LEDs, struggle to achieve uniform omnidirectional light distribution with a solid angle of 2π or more, as existing optical elements are either too large and costly or lack an efficient method to control light direction effectively.

Innovation Solution

A compact illuminating device design featuring a specific shape for the optical element's light exit surface, where the first light exit surface has a hollow around the optical axis, with a ratio of x-coordinate distances and angle conditions that determine the ratio of total internal reflection to refraction, allowing for uniform illumination in all directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a large optical element is used to control light direction, then light distribution uniformity is improved, but device size and manufacturing cost increase

Engineering Contradiction:

Improvelight distribution uniformityVSAvoidoptical element size

Core Design Contradiction:

Illumination intensityVSArea of stationary object

Solution Approach 1:

The optical element employs different surface curvatures at different locations: the first light exit surface has a first curvature and the second light exit surface has a second curvature. This local variation in surface quality allows compact control of light rays from different regions of the light source, achieving uniform omnidirectional distribution without requiring a uniformly large optical element throughout.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention transitions from controlling light in a single plane to controlling light in three-dimensional space by introducing a first light exit surface and a second light exit surface at different positions and orientations. This multi-surface approach enables omnidirectional light distribution (solid angle of 2π or more) within a compact footprint, resolving the contradiction between coverage and size.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If LED chips are arranged three-dimensionally to achieve omnidirectional radiation, then light distribution is improved, but manufacturing cost and thermal design complexity increase

Engineering Contradiction:

Improveomnidirectional light radiationVSAvoidmanufacturing cost and thermal design

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

Instead of arranging LED chips in three dimensions, the invention introduces an optical element as an intermediary between the surface light source and the surrounding environment. This optical element redirects and distributes the light emitted by the two-dimensional light source omnidirectionally, achieving the same lighting effect without the complexity of three-dimensional chip arrangement and associated thermal management challenges.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If an optical element with large size relative to light source is used, then ray control precision is improved, but device compactness deteriorates

Engineering Contradiction:

Improveray control precisionVSAvoiddevice compactness

Core Design Contradiction:

Manufacturing precisionVSVolume of moving object

Solution Approach 1:

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

The design enables uniform illumination in the forward, lateral, and backward directions, efficiently distributing light over a 2π solid angle, addressing the limitations of previous technologies by optimizing the light exit surface shape and size ratio.

Implementation Method 1

in 80% or more of an area in which x coordinate of a point is equal to or greater than x coordinate of the third point, an angle of incidence of light emitted at the first point is equal to or greater than the critical angle

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

in 80% or more of an area in which x coordinate of a point is equal to or smaller than x coordinate of the fourth point, an angle of incidence of light emitted at the second point is smaller than the critical angle

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS8118457B2Illuminating device

Publication Date: 2012.02.21 NALUX CO LTD

AI summary

An illuminating device includes a light source and a light receiving surface, first and second light exit surfaces. When a point at the edge of the light emitting surface is P2 and an axis which passes through a center P1 of a light emitting surface and is perpendicular to the light emitting surface is an optical axis, the optical element has a hollow around the optical axis. The first light exit surface is such that x coordinate of a point most distant from the optical axis on the first light exit surface is at least 1.5 times x coordinate of P2, that in 80% or more of an area in which x coordinate of a point is at least the x coordinate of another point P3, an angle of incidence of light emitted at P1 is at least the critical angle and that in 80% or more of an area in which x coordinate of a point is equal to or smaller than x coordinate of another point P4, an angle of incidence of light emitted at P2 is smaller than the critical angle.