Display Backlight Layout With Integrated IR Illumination
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Solution Overview
Problem
In mobile devices, the integration of infrared (IR) lighting for identification purposes often requires significant space, reducing the available area for the display screen, and existing solutions for IR lighting are inefficient and consume additional space with light guides.
Innovation Solution
A lighting device that integrates IR LEDs into a backlighting system with visible LEDs, using a light guide to redirect light for efficient IR illumination across the display screen, allowing for full-face coverage without a separate IR light source, optimizing display screen size and providing homogeneous illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate IR light source is integrated into the mobile device for identification purposes, then IR illumination capability is improved, but the available area for the display screen is reduced
Solution Approach 1:
The patent combines the IR LED and visible LED into a single integrated lighting device assembly. The IR LED and visible LED are mounted together on the same circuit board or substrate, sharing common structural support and electrical connection elements. This merging of previously separate components into one integrated unit reduces the total space required while maintaining both IR illumination and visible display functions.
Solution Approach 2:
The integrated lighting device serves multiple functions: the visible LED provides illumination for the display screen, the IR LED provides illumination for biometric identification, and both share the same mounting structure and electrical connection system. This multi-functional design allows a single component assembly to replace what would traditionally require separate dedicated components, thereby conserving space for the display screen.
2Adaptability or versatility
If light guides are used to redirect IR light around the display screen, then IR illumination is achieved, but the efficiency is reduced and additional space is consumed
Solution Approach 1:
The patent eliminates the light guide component from the IR illumination path. Instead of using light guides to redirect IR light around the display screen, the IR LED is positioned to illuminate the display screen directly. This extraction of the light guide element simplifies the optical path, removes the efficiency losses associated with light guide materials and interfaces, and reduces the space required for IR illumination components.
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
Enables efficient IR illumination for identification purposes without restricting the display screen size, as the IR LEDs are integrated into the backlighting system, providing effective IR lighting without the need for a separate IR light source, thus maximizing the display area.
Implementation Method 1
The light guide is configured to redirect light entering the light entry face towards the light exit face
Implementation Method 2
at least one visible LED capable to emit light in the visible range... at least one IR LED capable to emit light in the IR range
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
The invention refers to a lighting device for providing backlighting to a display screen (4). The object to provide a lighting device for providing illumination in the IR range, wherein the lighting device optimizes the available space for the display screen (4), is solved in that the lighting device comprises: a light guide (10) comprising at least one light entry face (12) and a light exit face (14), wherein the light guide (10) is configured to redirect light entering the light entry face (12) towards the light exit face (14), wherein the light exit face (14) is configured to be coupled to a back side of a display screen (4); at least one visible light-emitting diode (LED) (18) capable to emit light in the visible range, wherein the visible LED (18) is optically coupled to at least one light entry face (12); and at least one infrared (IR) LED (20) capable to emit light in the IR range, wherein the at least one IR LED (20) is configured to provide illumination for the light exit face (14). The invention further corresponds to an electronic device comprising the lighting device (9) according to the invention and a display screen (4). The invention also relates to a use of a lighting device (9) for optical identification and a light-emitting element (26).