Planar Illumination Coupling Member for Optical Axis Alignment
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Solution Overview
Problem
The challenge in planar illumination apparatuses is to maintain high luminance characteristics and positioning accuracy of optical axes between thin light guide plates and LEDs, particularly as the thickness of the light guide plate becomes smaller relative to the LEDs, leading to instability and potential breakage under external forces.
Innovation Solution
A planar illumination apparatus design that includes a light guide plate emitting light from its lateral surface, a substrate-mounted light source, a frame accommodating the components, and a first coupling member between the light guide plate and the light source, which couples them optically and structurally, using adhesive tapes to align and secure the optical axes while allowing for flexibility to absorb or reflect light, thus stabilizing the luminance and preventing breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the thickness of the light guide plate is reduced to meet thinning demands, then the overall profile is thinner, but the positioning accuracy of optical axes between the light guide plate and LED deteriorates
Solution Approach 1:
A coupling member is introduced as an intermediary component between the light guide plate and the LED. This coupling member includes a positioning protrusion that fits into a positioning recess, providing a mechanical interface that ensures accurate optical axis alignment. The coupling member acts as a mediator that transfers and maintains precise positioning relationships even when the light guide plate thickness is reduced, thereby resolving the contradiction between thinning and positioning accuracy.
2Length of stationary object
If the thickness of the light guide plate is reduced, then the apparatus is thinner, but the stability of luminance characteristics deteriorates
Solution Approach 1:
The coupling member serves as a stable intermediary structure that maintains consistent optical coupling between the LED and light guide plate. By providing a rigid positioning mechanism with precise geometric features (protrusion and recess), it ensures that the optical relationship remains stable despite the reduced thickness of the light guide plate, thereby maintaining stable luminance characteristics.
3Length of stationary object
If the thickness of the light guide plate is reduced, then the apparatus is thinner, but the risk of breakage and misalignment increases
Solution Approach 1:
The coupling member acts as a protective intermediary that mechanically links the light guide plate and LED through a robust positioning protrusion and recess interface. This interface provides misalignment prevention by constraining relative movement, and misalignment correction by maintaining the designed optical axis relationship. The coupling member thereby enhances the reliability and resistance to breakage of the thin light guide plate structure.
Data Source
AI summary
A planar illumination apparatus according to an embodiment includes a light guide plate that emits light from an emission surface, the light being incident on a lateral surface of the light guide plate; a light source that is arranged on the lateral surface side and has a light emitting surface that emits light to be incident on the lateral surface; a substrate that has two principal surfaces, a surface opposite to the light emitting surface of the light source being mounted on one of the principal surfaces; a frame that has a lateral surface and a floor surface, and accommodates the light guide plate, the light source, and the substrate; and a first coupling member that is arranged between the light guide plate and the floor surface and between the light source and the floor surface, and couples the light guide plate and the light source.