Key Lighting Assembly Light Guide Opaque Layer

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Solution Overview

Problem

Electronic devices face light leakage issues when backlighting keys, particularly due to light emission from undesirable areas such as the sides of keys or through materials that transmit light, which affects the effectiveness of key lighting assemblies.

Innovation Solution

A key lighting assembly comprising a keycap with a non-opaque portion for identification, a light guide optically coupled to an optical radiation source, and opaque layers to control light distribution, ensuring that light is transmitted only to the desired areas, thereby minimizing light leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light is emitted from the light guide to illuminate the key, then key visibility is improved, but light leaks from undesirable portions such as sides of keys

Engineering Contradiction:
Improvekey visibilityVSAvoidlight leak
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The keycap is divided into distinct portions: a non-opaque portion (such as a logo or text) that allows light transmission for visibility, and opaque portions that block light to prevent leakage. This segmentation enables different regions of the keycap to perform different optical functions, illuminating the identifier while containing light within desired boundaries.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the keycap have different optical properties. The non-opaque portion is designed to be translucent or transparent to allow light passage for identification, while surrounding areas are made opaque to prevent light leak. This local differentiation of material properties ensures light is directed only where needed.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If light is transmitted through the keycap material, then key identification is enhanced, but light leaks through the material to undesirable areas

Engineering Contradiction:
Improvekey identificationVSAvoidlight transmission through key material
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The keycap incorporates regions with different optical transmission properties. The identifier portion (logo, text, or symbol) is made of translucent or transparent material to allow light transmission for visibility, while the rest of the keycap body uses opaque material to block light and prevent leakage to adjacent areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The keycap structure is segmented into light-transmitting identifier regions and light-blocking body regions. This segmentation allows selective illumination of the key identifier while containing light within the intended viewing area, preventing unwanted light transmission through the keycap material.

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

The solution effectively illuminates the non-opaque portions of the keycap while preventing light from escaping through unlit regions, enhancing key visibility in low-light conditions without unnecessary light emission.

Implementation Method 1

an optical radiation source optically coupled to the light guide... The first opaque layer opening passes optical radiation through the gap to the keycap

Methodology Applied
Scientific EffectOptical radiation transmission: Light

Implementation Method 2

a first opaque layer disposed on a first surface of the light guide... a second opaque layer disposed on an interior surface of the keycap

Methodology Applied
Scientific EffectLight blocking: Absorption (EM radiation)

Data Source

PatentEP2535914B1Key lighting assembly
Publication Date: 2017.09.06 BLACKBERRY LTD
  • EP2535914B1 patent drawingFigure 1
  • EP2535914B1 patent drawingFigure 2
  • EP2535914B1 patent drawingFigure 3

AI summary

The present disclosure describes key lighting assemblies, electronic devices and keycaps. In one aspect, a key lighting assembly comprises a keycap defining at least one key. The keycap has one or more decorations. The assembly comprises a keycap, defining a key. The keycap has a non-opaque portion to identify the key. The assembly further comprises a light guide which is mounted in spaced relation with the keycap and an optical radiation source optically coupled to the light guide. The assembly further comprises a first opaque layer disposed on a first surface of the light guide. The first opaque layer defines a first opaque layer opening for passing optical radiation from the light guide to the keycap. The first opaque layer opening is located to permit optical radiation to be transmitted from the light guide to the non-opaque portion.