The Working Principle of a Colorimeter for Display Applications
A colorimeter is an instrument used to perform color measurements according to the response of the human eye, which determines the intensity of red, green and blue colored components of a self-illuminating object like a display. The instrument achieves this by measuring the intensity of different parts of the visual spectrum alike the human eye’s different photoreceptors.
A colorimeter consists of many different components that define its quality and accuracy. Three important components are the optics that define the viewing angle, the detectors (usually photodiodes) that detects the light that is transmitted through a third important component: optical filters.
Each of these components has their own spectral response. For accurate color measurements according to the human eye, it is important that the sum of these components (i.e. lens, filters, and photodiode) closely match the spectral sensitivity of the human eye as defined by CIE in 1931.
Colorimeter Working Principle
Any light within the visible spectrum is captured by one or more of the photodiodes responding to the X, Y and Z functions. These responses are not coincidentally chosen: these are based on the response of the human eye to short (blue), mid (green) and long (red) wavelengths. Each of these functions represent a certain sensitivity depending on the wavelength.
For example, light with a wavelength of 555nm corresponds to the highest sensitivity of the Y function. Wavelengths at the start and very end of the visual spectral range are not captured by the Y function detector as can be seen in the illustration below. By combining or triggering all three detectors in different proportions, a colorimeter is able to distinguish different colors, in a similar way to the human eye.
Colorimeters have a vast range of applications in various industries where color consistency and accuracy are key, such as the display industry. In such applications, colorimeters are used to measure displays to ensure every display shows exactly the same color palette.
The technical design of Admesy colorimeters enables them to measure color at high speeds and capture high-speed demanding parameters like flicker and response time analysis to determine the reaction time of a display.
Colorimeters from Admesy
Admesy has a range of colorimeters available to purchase. The MSE series provides precise, yet high-speed color measurements in a compact instrument. This colorimeter is the ideal choice for general in-line display color measurement applications to capture parameters like XYZ, Yxy, u’v’ and flicker.
The Hyperion series colorimeter from Admesy is the successor of the MSE series. This instrument provides the same parameters with near-perfect CIE1931 filter characteristics and ultra-high sensitivity. This allows accurate measurements even at low luminance levels in less time.
Correlating Display Measurements to the Human Vision
Watch the presentation of our ‘human vision and display geek’ Peter Karp held at the Electronics Display Conference 2021.