Vehicle Display Light Guide for Readability
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Solution Overview
Problem
Existing display devices for motor vehicles, particularly speedometers, face issues with reduced readability due to light loss and reflections from sunlight or street lighting, especially when using a light source for the rear pointer.
Innovation Solution
A display device with a light source arranged on the rear pointer's outer end and a light-guiding element concentrically enclosing the dial, minimizing light losses and allowing for improved readability, flexibility in pointer shape, and visual variations, including color and flashing displays, with the light-guiding element's exit surface angled to prevent user dazzle and enhance aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a light source is used for the rear pointer to display the set speed value, then the display functionality is improved, but light loss occurs and readability deteriorates due to reflections from sunlight or street lighting
Solution Approach 1:
A light-guiding element is introduced as an intermediary between the light source and the viewer. This element channels and directs the light from the rear pointer through a defined optical path, ensuring that the light reaches the viewer with minimal loss and without interference from external reflections, thus resolving the contradiction between display functionality and readability
Solution Approach 2:
The patent replaces traditional mechanical or direct optical display mechanisms with a light-guiding system. Instead of relying on direct light emission that is susceptible to environmental reflections, the system uses a structured light guidance mechanism that actively directs light to the viewer, substituting passive optical elements with an active light management system
2Illumination intensity
If the light-guiding element has a large light exit surface to improve visibility, then illumination is enhanced, but the user may be dazzled and aesthetics are compromised
Solution Approach 1:
The light exit surface of the light-guiding element is designed with local quality variations - different regions have different optical properties. The exit surface is angled and positioned to direct light specifically toward the viewer's expected position while avoiding direct illumination of the viewer's eyes, thus providing visibility without causing dazzle
Solution Approach 2:
The patent addresses the dazzle problem by transitioning from a two-dimensional light exit plane to a three-dimensional angular distribution of light. The light-guiding element is positioned and angled at specific dimensions (offset from the dial plane, inclined at specific angles) to control the spatial distribution of exiting light, directing it away from the viewer's eyes while maintaining visibility of the display
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
Significantly enhances readability and accuracy of the display with reduced light losses, allowing for flexible and aesthetically pleasing visual representations, including accurate tachometer scale readings and constant backlighting without shading.
Implementation Method 1
a light-guiding element (7) concentrically enclosing the dial (4) with a coupling surface (10) for the light from the light source (6)
Implementation Method 2
The light source (6) is arranged on the rear pointer (3), on its radially outer end section (5), and has a light-guiding element (7) concentrically enclosing the dial (4) with a coupling surface (10) for the light from the light source (6)
Data Source
AI summary
The invention relates to a display device (1) for a motor vehicle with two pointers (2, 3) arranged to pivot in parallel planes. The rear pointer (3) is covered by a circular dial (4) and is therefore invisible to the observer. To display a light bar (not shown) recognizable to the observer as a light marker, the rear pointer (3) has a light source (6) at its outer end section (5). This light source shines into a light guide element (7) that concentrically encloses the dial (4) and becomes visible at a light emission surface (8) inclined at 45° to the plane of the dial (4). In conjunction with a scale (9), the light marker thus enables a clear assignment of a value.