Watch Hand Light-Guide Layout to Eliminate Dial Illumination Hotspots
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Solution Overview
Problem
Existing luminous display devices for timepieces suffer from unwanted bright spots (hotspots) when viewed at angles greater than 30 degrees, impact optical efficiency, and allow direct view of the light source, leading to suboptimal design and reduced visual and aesthetic quality.
Innovation Solution
A luminous display device with a dial having a central hole and a peripheral wall extending above the dial to create a partitioned space housing the light source, masking it from view and improving optical efficiency by diffusing light through a light guide layer, while maintaining optimal component sizing and ventilation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the light source is positioned below the dial to avoid hotspots and direct view, then the aesthetic rendering is improved, but the optical efficiency deteriorates due to increased distance from the display needles
Solution Approach 1:
A light guide layer is introduced as an intermediary element between the light source and the display needles. This light guide layer captures light from the positioned light source and transmits it to the needles, bridging the optical gap created by positioning the light source below the dial. The light guide layer acts as a mediator that maintains both the aesthetic positioning and the optical efficiency.
Solution Approach 2:
The light transmission path is extended into a third dimension by introducing the light guide layer that extends vertically from the dial surface upward to the needles. This dimensional extension allows light to travel from the below-dial position to the needle position without direct line-of-sight exposure, resolving the contradiction between positioning and optical efficiency.
2Use of energy by moving object
If the light source is positioned close to the display needles to improve optical efficiency, then the optical performance is improved, but the light source becomes visible to users at viewing angles greater than 30 degrees
Solution Approach 1:
The light guide layer serves as a mediator that decouples the light source positioning from the needle illumination. The light source can be positioned optimally for optical efficiency while the light guide layer directs light to the needles without exposing the source to user view, thus resolving the visibility issue.
Solution Approach 2:
The optical path is segmented into distinct segments: light emission from the source, light transmission through the light guide layer, and light delivery to the needles. This segmentation allows independent optimization of each segment, enabling the light source to be positioned for optical efficiency while the light guide layer manages the visibility aspect.
3Device complexity
If a simple design without additional optical elements is used, then the device complexity is reduced, but the optical performance deteriorates due to light leakage and suboptimal light distribution
Solution Approach 1:
The light guide layer is a relatively simple optical element that provides significant optical performance improvement. It acts as an intermediary that guides light efficiently from the source to the needles, reducing light leakage and improving light distribution without requiring complex optical systems.
Solution Approach 2:
The light guide layer changes the optical parameters of the system by controlling light direction and distribution. It modifies the light path parameters to eliminate leakage and optimize illumination, achieving superior optical performance with minimal added complexity.
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 effectively conceals the light source from all viewing angles, eliminating hotspots and enhancing optical performance, visual rendering, and external aesthetics by optimizing component arrangement and reducing light leakage.
Implementation Method 1
a light guide layer arranged to diffuse all or part of a luminous flux emitted by a light source
Data Source
Figure 1~2
Figure 3
AI summary
One aspect of the invention relates to a luminous display device (1) configured to be arranged in a watch case, the display device (1) comprising a dial (2) having a dial body (20) having a central hole and an upper face (21), at least one hand (3, 4, 5) disposed above the dial (2) and mounted on a rotating shaft passing through the central hole of the dial body (20), the hand (3, 4) having a light-guide layer (31, 41) arranged to diffuse all or part of a luminous flux emitted by a lighting module (70) comprising an open partitioned space (10) delimited by a base (26) formed by a dial support (7) and by a peripheral wall (22) forming a screen made of the same material as said dial, said wall (22) being positioned around the rotating shaft of the hand (3, 4, 5) and extending above the dial body. dial (20) on a defined height,said lighting module (70) comprising a light source (6) disposed on the bottom (26) of this space (10) and arranged to emit a luminous flux in the direction of the needle (3, 4, 5) so as to illuminate it from below..,