Polarized Light Measurement for Vehicle Windshield Double Image
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing devices for measuring double images in vehicle windshields, caused by internal reflections, face difficulties in distinguishing between the primary and secondary beams due to significant brightness differences, making it challenging to accurately determine the double image angle.
Innovation Solution
A device with a light beam of linear polarization, oriented between 50° and 130° relative to the plane of incidence, enhances the brightness of the secondary beam, allowing for easier measurement of both beams using a light sensor with increased dynamic range and logarithmic resolution, and a converging lens to separate and evaluate the beams independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light beam is directed through the windshield onto a light sensor to measure double image angle, then the measurement of double images can be performed, but the primary beam is regularly many times brighter than the secondary beam making it difficult to measure both beams accurately
Solution Approach 1:
The patent changes the polarization state parameter of the light beam from unpolarized to linearly polarized at a specific angle (45° to 135° relative to the plane of incidence). This parameter change modifies the reflection characteristics at the windshield interfaces, thereby adjusting the brightness ratio between primary and secondary beams to enable accurate measurement of both beams by the light sensor.
Solution Approach 2:
The patent applies preliminary polarization filtering to the light beam before it enters the windshield. By pre-configuring the light source with specific linear polarization orientation, the system prepares the light in advance to optimize the brightness distribution of reflected beams, ensuring that both primary and secondary beams fall within the measurable dynamic range of the sensor.
2Measurement precision
If the light source is positioned such that the light beam does not coincide with the disk normal, then internal reflection and secondary beam formation occur, but the secondary beam brightness remains insufficient for easy measurement
Solution Approach 1:
The patent modifies the polarization parameter of the incident light beam to linear polarization at a specific angle range (45° to 135° relative to the plane of incidence). This parameter modification enhances the intensity of the secondary beam through optimized reflection coefficients, making the secondary beam sufficiently bright for accurate measurement while maintaining the necessary geometric configuration for double image formation.
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 increases the brightness of the secondary beam by a factor of 2, enabling accurate automation of double image angle measurement, independent of the light source's distance from the windshield, and allows for automatic evaluation of the pane's properties, such as wedge angle or curvature.
Implementation Method 1
If a light ray strikes a disk at an angle of incidence other than 0° with the disk's normal, internal reflection can occur within the disk, splitting the light ray into a primary and a secondary ray.
Implementation Method 2
The light beam exhibits linear polarization, the polarization direction forming an angle between 50° and 130° with the plane of incidence.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a device for measuring panes. The device comprises a light source and a light sensor which are arranged in such a way that a light beam emitted from the light source passes through the pane and impinges on the light sensor. According to the invention, the light beam has a linear polarization, wherein the polarization direction forms an angle of between 50° and 130° with an incidence plane stretching between the axis of the light beam and the pane normal at the point at which the light beam impinges on the pane. The light sensor is dimensioned such that both a primary beam and a secondary beam of the light beam impinge on the light sensor. The invention also relates to a corresponding method. According to the invention, the second beam has an increased brightness, so that it is easier to measure both beams.