Light Source Device Bypass Circuit for Faulty LED String
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Solution Overview
Problem
In light source devices, such as backlights for display devices, if one light emitting element fails, it can cause the entire string of connected elements to shut down, leading to decreased brightness and impaired image visibility across the display panel.
Innovation Solution
A light source device with a controller that detects abnormality in light emitting elements and switches to a bypass circuit to maintain functionality, allowing normally functioning elements to continue operating and compensating for the faulty ones by adjusting brightness and drive routes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If light emitting elements are connected in series to improve efficiency and reduce complexity, then the circuit structure is simplified and manufacturing is easier, but if one element fails the entire string shuts down causing significant brightness loss
Solution Approach 1:
The patent segments the series circuit into multiple independent groups by inserting switching elements between adjacent light emitting elements. Each group can be independently controlled and switched on or off. When an element fails, only its specific group is switched off while other groups remain operational, preventing total system shutdown and maintaining partial brightness.
2Strength
If all light emitting elements are turned off when one fails to prevent damage, then the faulty element is protected, but the overall brightness and image visibility significantly deteriorate
Solution Approach 1:
The patent applies local quality by enabling independent control of different circuit groups through switching elements. When a light emitting element fails, only the specific local group containing the faulty element is switched off for protection, while other local groups continue operating. This localized response maintains overall brightness and image visibility rather than shutting down the entire system.
3Reliability
If a bypass circuit is added to maintain functionality when elements fail, then reliability and image visibility are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent introduces switching elements as intermediary components between light emitting elements in series connections. These switching elements act as mediators that can selectively connect or disconnect individual elements or groups from the circuit. This intermediary mechanism enables bypass functionality without requiring complex parallel circuit arrangements, maintaining relative simplicity while improving reliability.
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
Prevents total shutdown of the display area affected by a faulty light emitting element, maintaining image visibility and brightness by isolating the faulty element and rerouting light through functional ones.
Implementation Method 1
a lightguide plate configured to take in the light from the light emitting elements and to pass the light through its exit surface
Data Source
AI summary
According to one embodiment, a light source device includes a plurality of light emitting elements including at least first and second light emitting elements, lightguide, first circuit, second circuit, and controller. The lightguide includes a first surface on which light from light emitting elements is incident and a second surface through which the light exits. The first circuit connects light emitting elements in series. The second circuit can bypass each of light emitting elements. The controller turns on light emitting elements using the first circuit if light emitting elements function normally, and if one of light emitting elements functions abnormally, the controller turns on the light emitting element functioning normally using the second circuit.