Light & Display Measurement

Blue Light Safety

Discussions in lighting safety standards has become a growing topic of conversation as we see the significant increase of modern solid-state lighting (SSL) light sources and UVC “blue light” in our daily environment.

One specific concern is that of photobiological safety and its direct correlation to blue light hazard (BLH). Blue light between 400 nm and 500 nm causes photochemical damage to the retina and may lead to degeneration of the macula. The current international Standard IEC 62471 contains guidelines for evaluating the photobiological safety of lamps and lamp systems. To ensure reliable evaluation, it places high demands on measuring equipment and procedures.

Konica Minolta Sensing and Instrument System provide measurement systems that can help determine the Blue Light Hazard risk of LED light sources and luminaires between 300 nm and 700 nm (i.e. only partially in the UV spectrum).  LEDs are classified by the international Technological Standards IEC 62471 for photobiological safety – the respective risk classes range from 0 (exempt) to 3 (high risk).

Konica Minolta Sensing and Instrument Systems offers two different Blue Light Hazard measurement systems, both based on our CAS 140D with stray light correction, covering the spectral range from 300 nm to 700 nm.  The stray light corrected CAS 140D Instrument Systems is the first to offer an array spectrometer that can reliably assess the blue light hazard from light sources within the prescribed limiting values. Prior, only double monochromators were recommended for this task, as an underestimation of the blue light hazard was possible in measurements with a spectroradiometer on array spectrometer basis due to stray light. The CAS 140D avoids this in two ways: The optics and mechanics used in the spectrograph block are optimized with regard to disturbing stray light. Additionally, a unique stray light correction matrix is integrated in the calibration procedure. Both innovations combined ensure an up to now unachieved precision in the determination of the blue light hazard with an array spectrometer.

Konica Minolta Sensing Americas has been providing resources and instruments for many years as well as setting UV LED calibration standards and addressing the hazards of blue light through our various testing processes. To learn more about our UV measurement instruments visit us at https://sensing.konicaminolta.us/us/technologies/uv-led-measurement/

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Importance of Display Contrast Measurement in Cockpit Instrumentation

Cockpit instrumentation in the aerospace industry has evolved over the past decades. In the past, control panels had backlit gauges, switches, and knobs, where now you are more likely to see an array of flat panel screens. There must be a consistent light and color emitting from these panels to reduce eyestrain, ease interpretation of data, and decrease distractions. In addition, they are comfortable to view equally in daylight and as well as night. Two key measurements are Luminance (a measure of brightness) and Display Contrast (the ratio between light and dark).

Luminance (Brightness) is a photometric measure of the luminous intensity per unit area of light traveling in a given direction. Brightness is defined as the luminance of the brightest component (white color) and is measured in candela per square meter (cd/m² = nit) or foot-lamberts (1fL=3.426 nits). Typically, display luminance varies from 100 nits, found in most office monitors, up to 1000 nits front projection systems.

There are varieties of units used for luminance. In most countries, the most common unit for luminance is candela/square meter (cd/m²). However, in the U.S., the most common unit is the foot-lambert (fL); 1 foot-lambert (fL) equals 1/π candela/square foot, or 3.426 cd/m². Professionals in the industry often use the term nit (nt). 1 nit unit is equivalent to 1 cd/m².

To measure luminance you can use a luminance meter such as the LS-150 or LS-160.

Display Contrast is the ratio between the brightest colors (in most cases white) and the darkest color (in most cases black) that the monitor is capable of producing. Where there is no industry standard in measuring contrast the generally accepted process is to measure parts of a screen and either take the average or highest white and the average or lowest black and express it in ratio form bright:dark. As an example, if a screen has bright luminance of 150 nits and a dark luminance of 1 nit the contrast ratio would be shown as 150:1.

With newer high performance, OLEDs with darker blacks are now producing much wider ratios. Hence, if a monitor can output 7500 nits with a white screen and 0.010 nits with a black screen, it would have a contrast ratio of 750,000:1. A higher contrast produces more in-depth images with better screen quality, giving richer colors that make it easier to interpret images and data. A decent LCD screen might have a contrast ratio of 1,000:1. The contrast on an OLED display is far higher, at around 4000:1, with ultra-high-end units beginning to get close to 1,000,000:1. When an OLED screen shows black, its pixels produce almost no light whatsoever.

A display's contrast ratio is one of the most important measurements of performance. In addition, it will be the most noticeable difference between two displays in a side-by-side comparison.

To measure contrast it is best to use a spectroradiometer such as the CS-2000 and CS-2000A. With high-end spectroradiometers, you can measure the darkest blacks down to super-low luminance of 0.003cd/m² allowing measurements up to 1,000,000:1.

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Why are Konica Minolta Sensing's Light Meters Superior?

Konica Minolta Sensing provides advanced optical technology that precisely measures the elements of color and light. Our light meters have become the staple in many national research and manufacturing environments, helping meet product quality and operational goals with less waste, time and effort.

Specifically, one should focus not only on an instrument that they know will last, but also one that comes backed with world class service and support. 

Konica Minolta Sensing stands behind each instrument sold by providing superior customer service support for Service & Application needs to our customers. All our customers are eligible to receive full Inspection, repair & calibration services to ensure performance and accuracy for the life of their instrument purchased through Konica Minolta Sensing. By using the Konica Minolta support services made available, you can rest assure that your overall cost for the product you purchased will indeed be lower.

What are Illuminance Meters?

Illuminance meter products are single element detectors that measure the intensity of light falling upon a surface as perceived by the human eye. It is measured in units known as foot-candles or in lux. The Konica Minolta illuminance meters are lightweight, compact, portable and provide a high level of accuracy and durability.

Why Konica Minolta Sensing Illuminance Meters?

A quality light meter must take into account the characteristics of Cosine Correction. The level of accuracy with this correction feature is very important in order to reduce measurement errors and correctly capture the illuminance as the human eye will perceive it. The accuracy of the meter is based on the response of the receptor which is proportionate to the cosine of the incidence angle in which the light is received. Konica Minolta’s Illuminance Meters T-10A/10MA is cosine corrected to within 3% of the ideal response curve.

How is this done?

The cosine corrected meter is designed in a way to prevent light from greater than 180 degrees to be included in measurement. The detector has 180-degree view and is typically used under a white diffuser dome. This is why our T-10A has an additional feature of a black rim around the white dome preventing any light, which is greater than 180 degrees, from being included and, hence influencing the measurement. This white diffuser design allows light entering it to be proportional to its angle of entrance to the meter’s overall response. 

Why is this important?

On cosine corrected meter light entering the diffuser directly above the detector at zero degrees (or straight down), has a maximum influence on measurement. But where other meters may fail the T10A separates itself from its competitors by providing a highly accurate measurement with its ability to align itself with the ideal response curve. When a meter is not cosine corrected, it will have more error included in the measurement and this can cause over or under estimation in the true value of Illuminance that is measured.

What are Luminance Meters?

Luminance meters are single element detectors that are filtered to measure photometric brightness as the human eye sees it. Luminance is measured in units known as candelas per meter square (Cd/m2) or Foot Lamberts (FtL). This type of meter measures the brightness of light that is emitted or reflected from a surface. and they are generally lightweight, compact and portable. They can usually connect to a PC using a software package which can evaluate or download the stored measurement data and to control the device.

Why Konica Minolta Sensing Luminance Meters?

An important factor in the performance of luminance meters is controlling and reducing the flare influence on a measurement. Flare factor is the degree to which the influence of light from outside the measurement area is eliminated. The Konica Minolta Luminance meters keep the flare factor to less than 1% even when the light outside the measuring area has very high luminance levels. This design allows the Luminance meter to give the level of performance expected by users of Konica Minolta instruments. The LS-160 series can also precisely measure very small (0.4mm) diameters using an optional closeup lens.

Why is this important?

An important question to ask is are we really measuring the just area we believe we are measuring? If you are unable to obtain the accuracy required of the measurement given, then you need to find the instrument that will provide this performance. If we do not have faith in the measurements, we obtain then the value of the data given will be of little use. It is important to know that the repeatability and accuracy of an instrument is consistent so that the overall cost of errors reduced to a minimum. 

When choosing an instrument, one should focus not only on an instrument that they know will last, but also one that comes backed with world class service and support. When equipment needs repairs or maintenance, your entire workflow may be disrupted. To prevent this, Konica Minolta Sensing offers rental equipment, or 48 hour expedited service to customers who can’t afford to be without their instrument for any length of time. As a result, your process remains seamless and uninterrupted.

Our dedicated staff strives to provide the best-in-class service. Customer service is our top priority. We focus on building a long-term relationship with every client and offering services that will enhance their business. At Konica Minolta, our factory-certified technicians are available to personally answer customer calls and support their hardware, software, and application needs throughout their equipment’s lifespan. Our service center is the only one in the United States that has factory trained engineers, tools, master instruments, and software required to service your Konica Minolta Sensing instrument properly. In order to ensure the accuracy of Konica Minolta products, Konica Minolta has established a system wherein the measuring instruments and other equipment used as in-house working standards are periodically re-calibrated utilizing higher standards, traceable to national standards, which have been established and are maintained by industrial standards organizations.

When choosing an instrument, one should focus not only on an instrument that they know will last, but also one that comes backed with world class service and support.

ISO/IEC 17025 enables an organization to demonstrate that they operate competently and generate valid results, thereby promoting confidence in their work both nationally and around the world. It also helps facilitate cooperation between laboratories and other bodies by generating wider acceptance of results.

Konica Minolta Sensing Americas has the right light measuring equipment to fit your individual budget and needs, whether you need to measure illuminance or luminance. Light meters are not all the same as needs differ from application to application. Konica Minolta provides the style and light meter most suited to your individual needs.

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