Distributing Light Guide Element for HMD Illumination Cost Reduction
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Solution Overview
Problem
Head-mounted displays (HMDs) requiring numerous laser diodes for illumination are expensive due to the high cost of laser diodes, making them unaffordable for widespread use in virtual reality applications.
Innovation Solution
The use of a distributing light guide element with light waveguides and a light guide, combined with a reflector, to efficiently distribute and emit light from a reduced number of laser diodes, reducing the overall cost by minimizing the number of diodes needed while maintaining uniform luminance and color consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large number of laser diodes are installed to provide sufficient illumination, then the illumination intensity is improved, but the cost of the head-mounted display increases
Solution Approach 1:
The patent divides the illumination system into multiple light guides that distribute light from a reduced number of laser diodes across different regions of the display panel, allowing each laser diode's light to be segmented and distributed to multiple areas through waveguide structures
Solution Approach 2:
The patent introduces light guides and waveguides as intermediary elements between the laser diodes and the display panel, enabling a small number of laser diodes to illuminate large areas by transporting and distributing light through these intermediary optical components
2Ease of manufacture
If the number of laser diodes is reduced to lower cost, then the cost is improved, but the uniformity of luminance distribution deteriorates
Solution Approach 1:
The patent applies different optical properties to different regions of the light guides, including varying extraction efficiencies, waveguide configurations, and reflector placements to ensure uniform luminance distribution across the display panel despite using fewer laser diodes
Solution Approach 2:
The patent modifies optical parameters such as refractive index, extraction efficiency, and waveguide geometry in different regions of the illumination system to compensate for the reduced number of laser diodes and maintain uniform luminance distribution
3Ease of manufacture
If the number of laser diodes is reduced to lower cost, then the cost is improved, but the color consistency deteriorates
Solution Approach 1:
The patent controls and maintains consistent optical parameters across all light guides, including wavelength, intensity, and spectral composition, to ensure that color consistency is preserved even when using a reduced number of laser diodes
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
This configuration allows for a cost-effective illumination system that reduces the number of laser diodes required, lowering the overall cost of the HMD while ensuring uniform luminance and color consistency, thereby making virtual reality technology more accessible.
Implementation Method 1
a distributing light guide element 10A, 10B and a light guide 20A, 20B. The distributing light guide element 10A, 10B includes side surfaces SS1A, SS1B opposing the plurality of light sources LS1, and light waveguides 11 extending from the side surfaces SS1A, SS1B
Implementation Method 2
The light emitted from the second end portion is reflected by the reflector, enters the light guide, propagates in the light guide, and is emitted from the first main surface
Data Source
AI summary
According to one embodiment, an illumination device includes light sources, a distributing light guide element and a light guide. The distributing light guide element has a first side surface, a second side surface and light waveguides extending from the first side surface towards the second side surface. The light guide has a third side surface and a first main surface. Each of the light waveguides have a first end portion into which light emitted from a corresponding light source enters, and a second end portion from which the light propagating in the light waveguide is emitted. The light emitted from the second end portion enters the light guide via the second side surface and the third side surface and is emitted from the first main surface.