Plasmon Coupling Display Element for High Luminance and Directivity
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Solution Overview
Problem
Projectors with solid state light sources face challenges in achieving both high luminance and directivity due to optical losses and etendue limitations, where light emitted from the light source cannot be effectively used unless its emission angle is within specific constraints, making it difficult to narrow the emission angle below ±15°.
Innovation Solution
A display element with a light valve section incorporating optical shutter means and plasmon coupling sections, including a carrier generation layer and a plasmon excitation layer with a higher plasma frequency than the light emitted, coupled with a wave number vector conversion layer to control the exit angle of light, allowing for high luminance and directivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light emitting element with high luminance output is used, then the light beam intensity increases, but the emission angle becomes wide (cannot be narrowed below ±15°)
Solution Approach 1:
A light guide plate is introduced as an intermediary component between the light emitting element and the optical modulation array. The light guide plate receives light from the light emitting element and guides it through internal reflection, converting wide-angle emission into directed light output. This mediator enables the system to achieve both high luminance and narrow emission angle by decoupling the light source's natural emission pattern from the required beam direction.
Solution Approach 2:
The patent changes the optical parameters of the light guide plate, specifically its thickness and refractive index properties, to control light propagation. By adjusting these parameters, the system optimizes the conversion of wide-angle light emission into a narrow, directed beam while maintaining high intensity. The light guide plate's physical parameters are engineered to achieve the desired emission angle control.
2Illumination intensity
If the emission angle of the light source is wide, then high luminance can be achieved, but optical loss increases due to light not entering the projection optical system
Solution Approach 1:
The light guide plate serves as a mediator that captures wide-angle light emission and redirects it into the acceptance angle of the projection optical system. Through internal reflection and controlled light guiding, it ensures that light which would otherwise be lost due to wide emission angles is efficiently channeled into the required angular range, reducing optical loss while preserving luminance.
Solution Approach 2:
The patent replaces mechanical optical shutters with a light guide plate-based optical system. Instead of mechanically blocking or directing light, the system uses optical principles (internal reflection, refraction) within the light guide plate to control light direction. This substitution eliminates mechanical complexity while achieving efficient light management and reduced optical loss.
3Use of energy by moving object
If optical shutters are used to control light transmission, then light use efficiency improves, but device complexity increases
Solution Approach 1:
The patent replaces mechanical optical shutter mechanisms with a light guide plate-based optical system. The light guide plate uses internal reflection and optical path control to achieve light transmission management without moving parts. This substitution maintains light use efficiency by controlling light direction optically rather than mechanically, while significantly reducing device complexity by eliminating mechanical shutters and their associated control systems.
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 a display element that achieves high luminance and directivity by controlling the emission angle of light, reducing optical losses and etendue, thereby improving light use efficiency and projecting high-quality images.
Implementation Method 1
a plasmon excitation layer stacked above the carrier generation layer and having a higher plasma frequency than a frequency of light generated in the carrier generation layer excited with light emitted from the light emitting element
Data Source
AI summary
The present invention includes light valve section (10) having substrate (22) through which light that exits plurality of optical connection mechanisms (23) that switch between the transmitting state and the shading state of light emitted from light emitting element (25) transmits and plasmon coupling section (11) that is arranged in light valve section (10) and that causes plasmon coupling to occur with light that exits light emitting element (25). Plasmon coupling section (11) includes carrier generation layer (15) that generates carriers with light that exits light emitting element (25) and plasmon excitation layer (17) that has a higher plasma frequency than the frequency of light that is generated in carrier generation layer (15) excited with the light emitted from light emitting element (25). Wave number vector conversion layer (19) is arranged on substrate (22). Wave number vector conversion layer (19) converts the light or surface plasmons generated in plasmon excitation layer (17) into light having a predetermined exit angle. Plasmon excitation layer (17) is sandwiched between first dielectric constant layer (16) and second dielectric constant layer (18).