Head-Up Display Infrared Absorbing Filter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Head-up display systems for vehicles face heating issues due to external radiation, such as solar radiation, which can reach the image generation unit through optical elements, leading to potential damage.
Innovation Solution
Incorporating a transparent part that is absorbent to infrared radiation between the reflective surface and the mirror in the head-up display device, positioned to intercept incoming radiation effectively, reducing heating at the image generation unit while maintaining transparency for visible light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the optical element is made transparent to allow visible light transmission, then the driver can see through it, but external infrared radiation can pass through and heat the image generation unit
Solution Approach 1:
The optical element is designed with different optical properties for different wavelengths: transparent to visible light (400-700nm) for driver visibility, but absorbent to infrared radiation (700nm-1mm) to prevent heating of the image generation unit. This wavelength-selective property resolves the contradiction by allowing beneficial visible light transmission while blocking harmful infrared radiation.
Solution Approach 2:
The optical element combines multiple materials or layers with complementary properties: a transparent substrate material (such as glass or plastic) for visible light transmission, combined with infrared-absorbing materials (such as metallic coatings, ceramic layers, or specialized polymers) to block infrared radiation. This composite structure enables simultaneous visible transparency and infrared absorption.
2Speed
If a reflective surface is used to redirect light, then the light beam can be directed to the driver, but external radiation can be reflected onto the image generation unit causing heating
Solution Approach 1:
Instead of using a purely reflective surface that redirects both visible light and infrared radiation, the patent inverts the approach by using a transparent optical element with wavelength-selective absorption. The system allows visible light to pass through while absorbing infrared radiation, effectively blocking the harmful reflected radiation before it can reach the image generation unit.
Solution Approach 2:
The optical element converts the potentially harmful incident infrared radiation into beneficial thermal energy absorption at a controlled location. By positioning the infrared-absorbing layer in the optical path, the system absorbs external infrared radiation before it can reach and heat the image generation unit, effectively using the absorption to protect sensitive components.
3Temperature
If a filter is added to block infrared radiation, then heating is reduced, but the device complexity increases
Solution Approach 1:
The infrared-absorbing layer is merged with the optical element itself rather than being a separate component. The coating or layer is applied directly to the transparent substrate, creating an integrated structure that combines visible light transmission with infrared absorption in a single element. This integration minimizes additional complexity while achieving the desired thermal protection.
Solution Approach 2:
The optical element serves multiple functions simultaneously: it acts as a transparent window for visible light transmission, a directional guide for the light beam, and an infrared radiation filter. By combining these functions in a single component with wavelength-selective properties, the system avoids the need for separate filters and maintains structural simplicity.
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 effectively attenuates infrared radiation, minimizing heating at the image generation unit without the need for complex reflective surfaces, while allowing visible light to pass through, thus protecting the unit from thermal damage.
Implementation Method 1
a part transparent for visible light, absorbent for infrared and interposed on the path of the light beam between the reflective surface and the mirror
Implementation Method 2
a reflective surface configured to reflect the light beam emitted by the image generation unit
Data Source
Figure 1~2
AI summary
A head-up display device (2) comprising an image-generating unit (6) designed to emit a light beam, a reflective surface (8) configured to reflect the light beam emitted by the image-generating unit (6) and a mirror (10) configured to receive the light beam reflected by the reflective surface (8). Provision is furthermore made for a part (12) that is transparent to visible light, that absorbs infrared and that is interposed on the path of the light beam between the reflective surface (8) and the mirror (10).