Holographic Watch Display Using Hand-Mounted LEDs and Waveguide Diffraction
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Solution Overview
Problem
Existing watch and clock display technologies face challenges in providing effective illumination in dark environments, particularly due to limitations in size and glare issues with direct lighting and hologram visibility.
Innovation Solution
A holographic display device with light sources at the ends of movable hands and glass surfaces featuring holograms and diffraction gratings, allowing for the reconstruction of holograms via diffracted light, enabling larger and clearer hologram display without direct glare, using LEDs or VCSELs for illumination and relief-etched gratings for mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If direct lighting is used to illuminate holograms in dark environments, then visibility is improved, but glare and direct light interference worsen
Solution Approach 1:
The patent introduces a waveguide as an intermediary optical element between the light source and the hologram. The waveguide captures light from the LED source and guides it through total internal reflection to illuminate the hologram indirectly, eliminating direct glare while maintaining visibility. This mediator structure allows light to reach the hologram without the viewer seeing the light source directly.
Solution Approach 2:
The patent transitions from direct 2D illumination to 3D waveguide-based indirect illumination. By using the waveguide's internal reflection paths and routing light through multiple dimensions within the glass structure, the system achieves indirect lighting that avoids direct glare while maintaining hologram visibility.
2Area of stationary object
If larger holograms are used to improve display size, then visibility and clarity are improved, but the complexity of integrating light sources and optical paths worsens
Solution Approach 1:
The waveguide structure serves multiple functions simultaneously: it acts as a light guide, a structural support for the hologram, and an optical element for total internal reflection. This multi-functionality reduces the need for separate components and simplifies the overall integration of large holograms with the lighting system.
Solution Approach 2:
The patent merges the light source, waveguide, and hologram into an integrated assembly. The LED is positioned within or near the waveguide structure, which then distributes light across the entire hologram area, eliminating the need for separate lighting and mounting structures that would increase complexity.
3Adaptability or versatility
If multiple light sources are used on different hands, then hologram reconstruction for multiple hands is improved, but the risk of colour interference and confusion worsens
Solution Approach 1:
The patent assigns different wavelengths (colors) to light sources on different hands. For example, the hour hand uses one wavelength while the minute hand uses a different wavelength. This color differentiation allows both hands to be illuminated and their holograms reconstructed simultaneously without visual confusion, as each hand's light is spectrally distinct.
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 provides enhanced visibility and clarity of holograms in dark environments by using indirect lighting with diffraction gratings, allowing for larger hologram sizes and avoiding direct glare, while maintaining durability and manufacturability.
Implementation Method 1
at least one movable hand having a light source at its peripheral end
Implementation Method 2
at least one diffraction grating, arranged on the internal surface of the glass to diffract light at an angle greater than the critical angle of total reflection
Implementation Method 3
diffract light at an angle greater than the critical angle of total reflection, at least one hologram being disposed on the glass in order to be reconstructed by the diffracted beam, preferably after total reflection at the external surface of the glass
Implementation Method 4
the light source(s) include(s) a waveguide housed inside the hand
Data Source
AI summary
The present invention concerns a holographic display device incorporated in a timepiece device comprising at least one movable hand, having a light source at its peripheral end, and a watch glass comprising at least one hologram at its periphery, said light source being arranged on the hand so that it reconstructs said hologram when it moves into a predetermined angular sector.