Light Guide Plate Orientation Recognition via Light-Receiving Face Protrusions
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Solution Overview
Problem
Light guide plates in backlight units face challenges in distinguishing between top and bottom surfaces, leading to uneven light intensity and increased device size due to tabs on side surfaces for orientation recognition.
Innovation Solution
A light guide plate with protrusions on the light-receiving face for easy orientation recognition, allowing for a compact design and preventing light from reaching the protrusions, thus maintaining even light intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If tabs are formed on two opposite side surfaces of the light guide plate for orientation recognition, then the orientation can be recognized, but the outer shape of the backlight unit becomes larger
Solution Approach 1:
The patent moves the orientation recognition features from side surfaces (horizontal dimension) to the light-receiving face (vertical dimension relative to light propagation). By forming protrusions on the light-receiving face instead of tabs on side surfaces, the orientation can be recognized without increasing the lateral dimensions of the backlight unit, thus resolving the contradiction between ease of operation and device size.
2Ease of operation
If tabs are formed on side surfaces remote from the light-receiving face, then orientation recognition is enabled, but incident light reaches these tabs and causes uneven light intensity
Solution Approach 1:
The patent extracts the orientation recognition function from the side surfaces and relocates it to the light-receiving face. By taking out the protrusions from positions where they would interfere with light propagation and placing them on the light-receiving face, the design eliminates the harmful effect of light reaching the orientation features while preserving the orientation recognition capability.
Solution Approach 2:
The protrusions on the light-receiving face serve as an intermediary solution that fulfills the orientation recognition function without becoming part of the light propagation path. They act as a mediator between the need for orientation recognition and the requirement for uniform light output, allowing both requirements to be satisfied simultaneously.
3Volume of moving object
If the light guide plate has a compact design without side tabs, then device size is reduced, but orientation recognition becomes difficult
Solution Approach 1:
The patent resolves this contradiction by transitioning the orientation recognition features from the lateral dimension (side surfaces) to the optical dimension (light-receiving face). This allows compact lateral dimensions while maintaining orientation recognition capability through protrusions that are visible during assembly but do not increase device size.
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 enables easy recognition of the top surface orientation, reduces device size, and prevents uneven light intensity by forming protrusions only on the light-receiving face, enhancing the quality of planar light emitted.
Implementation Method 1
a backlight unit described in Patent Document 1, for example, includes light guide plates 111 (111α, 111β) that receive light from a light emitting diode (LED) 122 and that convert the light to planar light by internal multiple reflection
Data Source
AI summary
Provided is a light guide plate that is suited for a compact illumination device emitting high-grade light and that allows the orientation thereof to be recognized with ease, an illumination device equipped with the light guide plate, and a display device equipped with the illumination device. Two protrusions (12A, 12B) are formed on a light-receiving face (11r) of a light guide plate (11), and these protrusions (12A, 12B) serve as a recognition member that allows the orientation of a top surface (11u) of the light guide plate (11) to be recognized.