Electrochromic Window Display Using Transparent Photovoltaic Converters
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Solution Overview
Problem
Conventional projector-based Head-Up Displays (HUDs) have limitations such as a small field-of-view due to image distortion at greater viewing angles, poor luminance contrast in bright conditions, and inability to produce dark graphics, restricting their use in vehicles.
Innovation Solution
A vehicle HUD system utilizing a window assembly with electrochromic pixels and transparent photovoltaic converters that switch between transparent and opaque states when irradiated with UV or IR radiation, allowing for wider viewing angles and improved visibility in bright conditions by creating visual contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional projector-based HUD is used, then content can be displayed on the windscreen, but the field-of-view is small due to image distortion at greater viewing angles
Solution Approach 1:
The display is segmented into individual electrochromic pixels that can be independently controlled. Each pixel acts as a separate light-modulating element, allowing the display to maintain image quality across wide viewing angles without the geometric distortion inherent in projected images.
Solution Approach 2:
The electrochromic pixels change their optical properties (from transparent to opaque) in response to electrical signals, enabling dynamic control of light transmission. This allows the display to present visual information that remains clear and undistorted across various viewing angles.
2Illumination intensity
If conventional projector-based HUD is used, then content can be displayed, but luminance contrast is poor in bright conditions
Solution Approach 1:
The electrochromic pixels dynamically adjust their light transmission properties, switching between transparent and opaque states. This enables the display to create high-contrast dark graphics that remain visible against bright daylight backgrounds, overcoming the limitation of projected images that become washed out in sunlight.
Solution Approach 2:
The system converts the harmful effect of ambient daylight into a beneficial contrast mechanism. By using electrochromic pixels that can become opaque, the display creates dark visual elements that stand out sharply against the bright outdoor environment, turning the challenge of daylight interference into an advantage for visibility.
3Adaptability or versatility
If conventional projector-based HUD is used, then content can be displayed on the windscreen, but the reflected image is only visible from the interior of the vehicle
Solution Approach 1:
The electrochromic pixel display serves multiple functions: it can be viewed from the interior of the vehicle like traditional HUDs, and simultaneously from the exterior of the vehicle. This dual-viewing capability makes the display system universal, accommodating both driver information needs and external communication needs without requiring separate systems.
4Ease of operation
If transparent photovoltaic converters and electrochromic pixels are used, then wider viewing angles and improved visibility are achieved, but device complexity increases
Solution Approach 1:
The system merges multiple functions into a single integrated window assembly. The photovoltaic converters, electrochromic pixels, and control electronics are combined in a unified structure that replaces traditional HUD projectors and combiners. This integration reduces the number of separate components and simplifies the overall system architecture despite the advanced functionality.
Solution Approach 2:
The window assembly serves multiple purposes: it generates electrical power through photovoltaic converters, displays visual information through electrochromic pixels, and provides structural integration with the vehicle window. This multi-functionality reduces the need for separate systems, thereby managing complexity through consolidation rather than multiplication of components.
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 system provides wider viewing angles and improved visibility for all vehicle occupants, with the ability to display content that is visible both inside and outside the vehicle, even in bright conditions, and supports larger display areas without distortion.
Implementation Method 1
Each transparent photovoltaic converter can produce an electric current when irradiated with ultraviolet or infrared radiation to switch one or more of the electrochromic pixels from the inactive state to the active state
Implementation Method 2
electrochromic pixels arranged on the base layer and switchable between an inactive state and an active state
Data Source
AI summary
A vehicle head up display system includes a transparent window assembly and an ultraviolet or infrared light source. The light source is used to irradiate transparent photovoltaic converters in the window assembly so that the photovoltaic converters produce an electric current. The electric current is transmitted to electrochromic pixels in the window assembly and actuates the electrochromic pixels in the window assembly to switch between having a transparent appearance and having an opaque appearance. Visual contrast between transparent pixels and opaque pixels provide indicia on the window assembly. The indicia can be removed from the window assembly by actuating the opaque pixels to have the transparent appearance by a subsequent application of electric current exceeding the threshold voltage. An electronic control unit can be including in the system for controlling operation of the light source.