Dual-Function Light Guide for LCD Backlight Adjustment
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Solution Overview
Problem
Conventional portable computing devices with LCD backlights face issues of excessive brightness in dim ambient light and insufficient brightness in bright ambient light, affecting the clarity of information displayed, and existing solutions increase manufacturing costs due to integrated light sensors.
Innovation Solution
A portable computing device with a dual-function light conduit that adjusts backlight intensity based on external ambient light levels, using a light controller and ambient light sensor to determine and respond to changing light conditions, allowing for improved visualization of information across a wide range of ambient light levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a light sensor is incorporated into the LCD to automatically adjust backlight intensity, then the clarity of displayed information is improved across varying ambient light levels, but the manufacturing cost of the LCD increases
Solution Approach 1:
The patent applies the universality principle by making the light guide serve dual functions: it continues to guide light from the backlight to illuminate the LCD, and simultaneously acts as an optical path for ambient light to reach the light sensor. This eliminates the need for a separate light sensor housing or additional optical components, thereby avoiding increased manufacturing costs while enabling automatic backlight adjustment functionality
Solution Approach 2:
The patent merges the light guide and light sensor optical path into a single integrated structure. The light sensor is positioned to receive ambient light through the same light guide that delivers backlight illumination, combining two optical functions into one component system. This integration reduces component count and assembly complexity, maintaining ease of manufacture while achieving automatic backlight control
2Reliability
If the backlight intensity is set to a fixed high level, then the information displayed on the LCD is viewable in bright ambient light, but the backlight becomes excessively bright in dim ambient light conditions
Solution Approach 1:
The patent implements feedback control by using the light sensor to continuously monitor ambient light levels and automatically adjusting the backlight intensity accordingly. The light sensor detects ambient light through the light guide, and the controller modulates the backlight output to maintain optimal display visibility without excessive brightness, creating a closed-loop control system that adapts to varying lighting conditions
Solution Approach 2:
The patent transitions from a static fixed-intensity backlight system to a dynamic adjustable-intensity system. The backlight intensity is no longer fixed but varies dynamically based on real-time ambient light conditions detected by the light sensor, allowing the system to optimize visibility across different lighting environments while avoiding excessive brightness in dim conditions
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 adjusts backlight intensity to enhance information clarity in varying light conditions without increasing manufacturing costs, providing improved usability and visibility in different ambient light environments.
Implementation Method 1
a light conduit terminating at the external surface for conveying light between the event notification lamp and the external surface
Implementation Method 2
The light sensor measures the luminous energy at two or more wavelengths
Data Source
AI summary
A portable computing device includes a housing having an external surface, and an event notifier, a display device, and a light controller disposed within the housing. The event notifier includes an event notification lamp, and a light conduit terminating at the external surface for conveying light between the event notification lamp and the external surface. The display device includes illumination means for improved visualization of information rendered on the display device. The light controller is coupled to the event notifier and the illumination means. The light controller is configured to determine the intensity of ambient light external to the housing via the light conduit, and to adjust the intensity of light emitted by the illumination means in accordance with the determined ambient light intensity.