Key Pad Light Guide Frame for Even Backlighting

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Solution Overview

Problem

Existing keypad backlighting technologies for mobile devices often require significant space for light emission and do not effectively distribute light evenly across the keypad, leading to inefficiencies in illumination and user experience.

Innovation Solution

A keypad assembly incorporating a light guide assembly with a combination of a light guide film and a light guide frame, utilizing side firing LEDs and micro features to direct light efficiently towards the keys, while providing structural support and reducing the overall thickness of the keypad.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If traditional backlighting methods are used with separate light emission components, then light can be emitted to illuminate keys, but the keypad thickness increases and space is consumed

Engineering Contradiction:
Improvebacklighting illuminationVSAvoidkeypad thickness
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The patent combines the light guide function and structural support function into a single light guide frame component. This frame structure serves dual purposes: it guides light from the light source to illuminate the keys while simultaneously providing mechanical support for the keypad assembly, thereby eliminating the need for separate support structures and reducing overall thickness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light guide frame is designed to perform multiple functions: light guidance, structural support, and potential integration with other keypad components. This multi-functional design reduces the number of separate components needed, optimizing space utilization and reducing keypad thickness while maintaining illumination functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Illumination intensity

If light is directed toward keys using conventional methods, then keys are illuminated, but light distribution is uneven across the keypad

Engineering Contradiction:
Improvelight distribution uniformityVSAvoidlight guiding structure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The light guide frame incorporates different surface characteristics at different locations to optimize light distribution. By varying the optical properties (such as reflective or diffusive surfaces) at specific areas of the frame, the patent achieves more uniform light distribution across the keypad without requiring complex additional components.

Inventive Principle:
Principle #3Local quality

3Illumination intensity

If additional space is allocated for light emission components, then effective backlighting is achieved, but the overall device size increases

Engineering Contradiction:
Improvebacklighting effectivenessVSAvoidkeypad area
Core Design Contradiction:
Illumination intensityVSArea of stationary object

Solution Approach 1:

The patent transitions from a traditional linear light path to a frame-based light guidance structure that utilizes two-dimensional light distribution. This dimensional change allows light to be guided more efficiently across the keypad surface, achieving effective illumination without requiring additional linear space or increasing the overall keypad area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 ensures even backlighting across the keypad, enhances user experience with improved tactile feedback, and reduces the keypad's thickness by eliminating the need for additional space typically required for light emission, while maintaining efficient light distribution.

Implementation Method 1

A keypad assembly incorporating a light guide assembly with a combination of a light guide film and a light guide frame, utilizing side firing LEDs and micro features to direct light efficiently towards the keys

Methodology Applied
Scientific EffectLight guidance: Waveguide (optics)

Implementation Method 2

utilizing side firing LEDs and micro features to direct light efficiently towards the keys

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP2426688B1Backlighting assembly for a keypad
Publication Date: 2015.08.12 BLACKBERRY LTD
  • EP2426688B1 patent drawingFigure 1
  • EP2426688B1 patent drawingFigure 2
  • EP2426688B1 patent drawingFigure 3

AI summary

A backlighting assembly (560) for use in a keypad assembly (400). The backlighting assembly (560) includes at least one light emitting source (461) configured to emit light (462); and a light guide assembly (470) configured to receive the emitted light (462) and direct the light toward the at least one key (410). The light guide assembly (470) includes both a light guide film (471) and a light guide frame (475) for directing light from the light source (461) toward the key(s) (410).