Electronic Lock Keypad With Edge-Fed Light Guide for Low-Energy Illumination
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Solution Overview
Problem
Existing electronic locks face challenges in maintaining low energy consumption, particularly when powered by internal energy sources, while ensuring frequent battery replacement is minimized and providing a satisfactory user experience in terms of security, reliability, and visual quality.
Innovation Solution
The electronic lock incorporates a backlit keypad with a light guide and touch sensors, where character boldness increases along the axis of light propagation to compensate for optical losses, ensuring consistent brightness and energy efficiency by minimizing the need for constant illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light guide is used to illuminate the keypad characters, then the visual quality and user experience are improved, but the energy consumption increases
Solution Approach 1:
The light guide is positioned only in the region where characters are displayed, rather than illuminating the entire keypad surface. This localized illumination approach provides sufficient visibility for user input while minimizing overall energy consumption compared to full-keypad illumination.
Solution Approach 2:
The keypad illumination is activated periodically or on-demand based on user interaction states, rather than continuously. The system illuminates the keypad when needed (e.g., when a user approaches or interacts with the lock) and deactivates it during idle periods, reducing total energy consumption while maintaining visual quality when required.
2Use of energy by moving object
If the light source is positioned close to the characters for efficient illumination, then the energy consumption is reduced, but the optical losses in the light guide increase
Solution Approach 1:
Instead of positioning the light source directly adjacent to each character in a planar arrangement, the light guide extends light propagation in a third dimension (depth/thickness direction) through its structured geometry. This allows the light source to be positioned at an optimal location while the light guide efficiently distributes illumination across the character region through its three-dimensional light-guiding structure.
Solution Approach 2:
The light guide acts as an intermediary element between the light source and the characters. It receives light from the light source and redirects/transmits it to the character regions, enabling the light source to be positioned at an energy-efficient location while still achieving effective illumination of all characters despite optical losses.
3Reliability
If the keypad is always illuminated to ensure visibility, then the user experience and reliability are improved, but the battery life decreases
Solution Approach 1:
The keypad illumination is made dynamic rather than static - it automatically activates and deactivates based on detected user presence or interaction states. When a user approaches or interacts with the lock, the illumination activates to ensure visibility and reliable access. When no user is present, the illumination deactivates to conserve battery life, extending the operational duration of the lock.
Solution Approach 2:
The system uses feedback from sensors (such as proximity sensors, touch sensors, or motion detectors) to control the illumination state. When sensors detect user presence or keypad interaction, they provide feedback to activate the illumination, ensuring reliable user access. When sensors indicate absence, the feedback deactivates illumination to extend battery life.
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 maintains consistent keypad brightness and reduces energy consumption by optimizing light propagation, enhancing user experience and extending battery life without frequent replacements.
Implementation Method 1
a light guide underlying the wall portion, the light guide being flat, parallel to the wall portion, and having a thickness, the light guide being optically coupled to the translucent areas via the internal face
Data Source
AI summary
The electronic lock can have a housing having a wall portion being flat, and a keypad. The keypad can have a sequence of characters aligned along an axis parallel to the wall portion, defined by corresponding translucent areas extending across the thickness of the wall portion; a set of touch sensors underlying corresponding ones of the characters of the sequence; a light guide underlying the wall portion, the light guide being flat, parallel to the wall portion, and having a thickness, the light guide being optically coupled to the translucent areas via the internal face; and a light source offset from the plurality of characters, operable to propagate light into an edge surface of the light guide, for the light to propagate within the light guide in a direction of the axis.