Waveguide Member Recesses for Keypad Illumination
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Solution Overview
Problem
Conventional keypad assemblies for portable wireless terminals suffer from significant light leakage and loss due to inefficient rear lighting systems, which hinder the development of compact and power-efficient devices.
Innovation Solution
Incorporation of a waveguide member with recesses and light blocking layers to minimize light leakage by reflecting and diffusing light within the waveguide, ensuring that light is directed towards the key buttons while preventing unnecessary loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional rear lighting means are used to illuminate key buttons, then key buttons can be illuminated, but a considerable amount of light is directed to the periphery and lost
Solution Approach 1:
A waveguide member is introduced as an intermediary between the light source and key buttons. The waveguide captures light from LEDs and guides it through total internal reflection, directing it precisely to the key buttons while preventing peripheral light loss. This mediator structure transforms the direct illumination approach into a controlled light guiding system.
Solution Approach 2:
The waveguide member utilizes changes in the refractive index parameter between the waveguide material and surrounding air to achieve total internal reflection. By carefully selecting materials with appropriate refractive indices, the system maintains light within the waveguide until it reaches the intended key button areas, minimizing energy loss.
2Illumination intensity
If conventional rear lighting means are used, then key buttons can be illuminated, but light is directed to the periphery and lost
Solution Approach 1:
The waveguide member serves multiple functions simultaneously: it acts as a light guide, a structural support element, and a light distribution mechanism. By integrating these functions into a single component, the design reduces overall system complexity while achieving effective key button illumination without peripheral light loss.
Solution Approach 2:
The waveguide member combines the light guiding function with the structural framework of the keypad assembly. Rather than adding a separate complex lighting system, the waveguide is integrated into the existing structure, merging optical functionality with mechanical support to simplify the overall device design.
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 reduces light leakage, enhancing key button illumination and power efficiency by ensuring that light is focused on the intended area, thereby improving the overall performance and usability of portable wireless terminals.
Implementation Method 1
a waveguide member including a waveguide for guiding light coupled to an inside and at least one recess formed in a direction perpendicular to the direction of guidance of light coupled to the inside of the waveguide so that light guided by the waveguide is reflected to the waveguide
Implementation Method 2
at least one recess is formed in a direction perpendicular to the direction of guidance of light coupled to the inside of the waveguide, so that light guided by the waveguide is reflected to the waveguide
Data Source
AI summary
Disclosed are a waveguide member and a keypad assembly including the same. The waveguide member includes a waveguide for guiding light propagated inside, and at least one recess formed in a direction perpendicular to a direction of guidance of light coupled to the inside of the waveguide so that light guided by the waveguide is reflected to the waveguide. The keypad assembly includes a keypad having at least one key button and an elastic sheet fixing the key button, a waveguide member positioned beneath the keypad, the waveguide member having a waveguide for guiding light coupled to an inside and at least one recess for reflecting light guided by the waveguide to the waveguide, and a switch pad positioned beneath the waveguide member so as to establish an electric contact when the key button is pressed.