R&D in the Automotive Industry Using White Point Adjustment and Color Measurement

Critical design factors in the automotive industry include the quality of lighting and displays. Measuring the colors emitted from the lights and displays accurately allows high-quality, precise results. The key solutions for accurate color measurement in vehicle design and manufacturing are outlined in this article.

Figure 1. Lighting and displays are an essential aspect of vehicle design. Image Credit: xusenru/pixabay.com.

The automotive market is becoming more competitive. Safer, better, more reliable vehicles that provide a more enjoyable driving experience are being demanded by consumers. In recent decades this has resulted in a flurry of technological advances in the automotive industry. Automotive lighting and design are no exception to this trend, with a number of significant innovations.

Automotive Lighting Research Enhances Efficiency and Design

From halogen lamps which were introduced in the 1970s, to xenon lamps introduced in the 1990s, to full LED headlamps introduced in 2006, exterior vehicle lights have advanced quickly. When compared to their predecessors LED headlamps provide increased efficiency, longer lifetimes, and reduced energy consumption.

Additionally, adaptive driving beam technologies which were introduced in 2014 now enable headlights to automatically adapt to every driving situation. Laser lights are the latest trend in headlights, offering diodes that are a fraction of the size of LEDs while providing superior quality, efficiency, and performance.^1-4

Interior lighting is also becoming a more critical part of vehicle design, studies have shown that ambient interior lighting can enhance vehicle attractiveness, space perception and perceived safety. LEDs are the primary lighting source presently employed in interior lighting, but there is ongoing research into OLEDs, which provide more design flexibility, and optical fibers, which provide compactness.

Whilst interior lighting is currently focused on enabling a superior driver experience, the introduction of autonomous vehicles could wholly alter how we interact with our vehicles.^6,7

Color Quality of Vehicle Lighting and Displays is an Essential Design Consideration

To ensure increased customer satisfaction and a high-quality product, measuring and adjusting optical properties of vehicle components during research and development is crucial. Vehicle manufacturers and automotive OEMs aim to plan their design and lighting schemes precisely to meet regulatory and consumer demands.

Sadly, mass production processes can result in small variations in composition, material structure, and thickness which result in color differences and spectral variations in automotive displays and lights.^8-10

Color reproduction and white point adjustment are a key process of quality control in automotive research and development. Color measurement can be carried out using a spectroradiometer or colorimeter.^11-13

Measuring Color – Colorimeter or Spectroradiometer?

Whilst both devices provide a ‘correct’ measurement of color, they do it in ways that are very different. The context of the measurement often determines the best choice of device as a result.^11-13

Colorimeters measure color in a similar way as the human eye does, according to a set of coordinates (XYZ, or red, green, blue). When color is measured with a colorimeter, you get three values that can be translated to a color point in, for example, the CIE 1931 diagram.

One of the downsides of employing a colorimeter to measure color is that a lot of the time the same color can be attained using different spectrums of light. Therefore, colorimeters could not tell the difference between many varieties of white light, but this does not mean that the lights are spectrally the same.^11,12

Figure 2. CIE 1931 diagram, with the white point marked.

Spectroradiometers provide a spectrum with a ‘truer’ reflection of the color, by dispersing and measuring the intensity of each wavelength of light in a light source. As a result, spectroradiometers can differentiate between different spectrums of light that all appear to be the same color, for example different varieties of white light (see Figure 3). ^11-13

Figure 3. Spectra of several “white” light sources measured using a spectroradiometer. Image credit: Admesy.¹³

There are advantages and disadvantages to both light analysis devices. Whilst spectroradiometers provide a more detailed measurement of the light source, they are generally slower, more expensive, and more complex to operate and interpret than colorimeters. Colorimeters offer outstanding repeatability.^11-13

Colorimeters are extremely accurate for routine comparisons and color measurements. As a result, they are critical for quality control and are frequently utilized in the production and inspection phases of manufacturing. On the other hand, spectroradiometers provide a larger degree of versatility, flexibility, and specificity. Spectroradiometers are the ideal versatile solution for the vehicle research and development process, including color formulation and lighting system development.^12-15

Color Measurement Solutions from Admesy

Admesy supplies a wide variety of instruments focused on light and color measurements. Including spectroradiometers and colorimeters that are perfect for a range of automotive development and manufacture applications. The Hyperion colorimeter provides almost perfect CIE 1931 filter characteristics which are combined with low noise circuitry and high sensitivity, resulting in a high-performance colorimeter in a robust and user-friendly system.

Admesy offers two options for applications that require a spectroradiometer: the Hera series and the Rhea series. The Hera series provides spectral measurement solutions which are robust and compact while maintaining high-performance. The Rhea series allows flexible, high-end spectral measurement solutions.^16-17

References and Further Reading

1. ‘Fundamentals of Automotive and Engine Technology’ — Reif K, Springer, 2014.
2. ‘A review on light-emitting diode based automotive headlamps’ — Long X, He J, Zhou J, Fang L, Zhou X, Ren F, Xu T, Renewable and Sustainable Energy Reviews, 2015.
3. ‘Solid-State Automotive Lighting: Implications for Sustainability and Safety’ — Bullough JD, Sustainable Automotive Technologies, 2012.
4. ‘The Next Step — Pure Laser High-Beam for Front Lighting’ — Fiederling R, Trommer J, Feil T, Hager J, Auto Tech Review, 2016.
5. ‘Reality Check: Laser High Beam Performance in Real Driving Tests’ — Albrecht KF, Austerschulter A, Rosehahn EO, 11th International Symposium on Automotive Lighting, 2015.
6. ‘Influence of ambient lighting in a vehicle interior on the driver’s perceptions’ — Caberletti L, Elfmann K, Kummel M, Schierz C, Lighting Research and Technology, 2010.
7. ‘Effects of Automotive Interior Lighting on Driver Vision’ — Flannagan MJ, Devonshire JM, The Journal of the Illuminating Engineering Society , 2012.
8. ‘Colorimetry Applications In The Automotive Industry’ — Chao MK, Hake BP, Electro-Optical Instrumentation for Industrial Applications, 1983.
9. ‘Advanced Imaging Colorimetry’ — Konjhodžić Đ, Khrustalev P, Young R, Information Displays, 2015.
10. ‘11^th International Symposium on Automotive Lighting’ — Khanh TQ, Herbert Utz Verlag, 2015.
11. ‘Colorimetry: Fundamentals and Applications’ — Ohta N, Robertson A, John Wiley & Sons, 2006.
12. ‘Measuring colour in a world of light’ https://www.admesy.com
13. ‘Spectrometry: General Spectrometry’ https://www.admesy.com/application/general-spectrometry/
14. ‘Visual and Instrumental Assessments of Color Differences in Automotive Coatings’ — Gómez O, Perales E, Chorro E, Burgos FJ, Viqueira V, Vilaseca M, Martínez-Verdú FM, Pujol J, Color Application and Research, 2016.
15. ‘Hyperion Series’ https://www.admesy.com/product/hyperion-i/
16. ‘Hera Series’ https://www.admesy.com/
17. ‘Rhea Series’ https://www.admesy.com/product/rhea/

This information has been sourced, reviewed and adapted from materials provided by Admesy.

For more information on this source, please visit Admesy.