Characterization Archives - PISÉO https://piseo.fr/en/characterization/ Design and Characterization of Innovative Optical Systems Tue, 10 Sep 2024 12:40:21 +0000 en-US hourly 1 https://wordpress.org/?v=7.0 https://piseo.fr/wp-content/uploads/2020/02/cropped-minioeilpiseo2-1-90x90.png Characterization Archives - PISÉO https://piseo.fr/en/characterization/ 32 32 On-site optical risk assessment https://piseo.fr/en/press-news/news-en/optical-risk-assessment/ Fri, 07 Oct 2022 13:05:27 +0000 https://piseo.fr/?p=22516 Sources of artificial light such as LEDs (non-coherent) and lasers (coherent), as well as the systems that integrate them, can, under certain conditions, cause deleterious effects on the human body. Radiation from these sources is present in the ultraviolet (UV), visible, and infrared (IR) ranges. Also, European regulations provide provisions to protect people from the […]

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]]> Sources of artificial light such as LEDs (non-coherent) and lasers (coherent), as well as the systems that integrate them, can, under certain conditions, cause deleterious effects on the human body. Radiation from these sources is present in the ultraviolet (UV), visible, and infrared (IR) ranges.

Also, European regulations provide provisions to protect people from the risks of potentially dangerous radiation.

In the professional field, employers must respect the legislation and implement means to protect employees against this potentially harmful exposure. To do this, they must first assess the optical risks related to working conditions based on the regulations and international standards in force and on the advice of experts in the field.

Regulations and standards concerning optical risk

In order to protect individuals, the Council of the European Union and the Parliament have adopted directives and regulations with which products and devices incorporating UV sources and their use must comply. These directives refer to so-called harmonized standards enabling compliance with this regulation. Finally, the scientific community has written publications to specify the UV systems in line with their application.

The European regulatory and normative system concerning worker exposure to UV risk can be summarized in the diagram below.

In France, the labor code and decree also regulate worker exposure to UV risks. The exposure limits and UV risk assessment methods are also described in the standards. The assessment of the UV risk for workers on an illumination system, for example, is therefore mandatory.

On-site optical risk assessment

Thanks to their skills and mobile radiometric test equipment, PISÉO experts can carry out on-site optical risk assessments in order to report on employee exposure to artificial optical radiation and allow employers to take appropriate measures to prevent these risks. Indeed, PISÉO experts take part in the standardization work of AFNOR and IEC on optical safety within the framework of the UF76 and TC76 committees and carry out radiometric measurements using the spectroradiometers of their laboratory accredited to ISO 17025 by the COFRAC (scope available on www.cofrac.fr).

 

Recommendations to reduce optical risks

The optical risk can be reduced in several ways:

– using light sources with low optical risk,

– by integrating the light sources into the systems in such a way that the optical risk is limited,

– by informing users of sources and systems by markings indicating the presence and level of risk,

– by using protection either in the installation and/or by providing employees with appropriate personal protective equipment.

PISEO experts are able to support you in reducing the optical risk in all of these situations by offering you consulting, optical and mechatronic design and characterization services in the laboratory and on-site.

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]]> Characterization of materials for optics https://piseo.fr/en/press-news/news-en/characterization-of-materials-for-optics/ Thu, 08 Sep 2022 12:08:38 +0000 https://piseo.fr/?p=21386 Illumination, detection and visualization systems integrate optical components manufactured and treated from different (optics) materials. Indeed, these materials transmit, reflect, absorb, diffuse optical radiation in various ways and thus influence the performance of the systems that integrate them. PISÉO’s experts use these materials to design innovative and high-performance optical systems. They therefore have a very […]

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]]> Illumination, detection and visualization systems integrate optical components manufactured and treated from different (optics) materials. Indeed, these materials transmit, reflect, absorb, diffuse optical radiation in various ways and thus influence the performance of the systems that integrate them.

PISÉO’s experts use these materials to design innovative and high-performance optical systems. They therefore have a very large database of the optical characteristics of marketed materials such as polymethyl methacrylate (PMMA), polycarbonate (PC), glasses and anti-reflective coatings. The experts use these characteristics to perform simulations with tools such as LightTools or Zemax. They predict the performance achievable by optical systems once integrated including yields, illuminance, luminance, distortion, modulation transfer function (MTF) and colorimetry.

PISÉO is therefore an innovation platform and center of expertise in optics-photonics. To support its experts in optical design and its customers, PISÉO offers characterization services for materials for optics such as those described below:

Measurement of the refractive index according to the wavelength

The refractive index varies with wavelength. Its precise measurement makes it possible to limit the risks of chromatic aberrations in an imaging system and to see colored fringes appear.

In a monochromatic system, the optical system will be optimized according to the material used. The simulated performances will be as close as possible to those measured.

Measurement of spectral linear transmittance

The transmittance of a material varies according to the wavelength and its thickness. PISÉO’s optical design experts can give precise photometric and radiometric performance according to the thicknesses of the materials envisaged and the sources used. Recommendations can be made on the use of different materials depending on the application and the industrial constraints of our customers.

spectral linear transmittance
materials for optics

Characterization of scattering materials

Diffusing materials are increasingly used to obtain light homogeneity and perfect uniformity, without hot spots. The diversity of materials makes the choice complicated depending on the application, such as lighting, automotive or visualization. PISÉO’s experts rely on precise measurements of materials from different manufacturers to calculate the uniformity and optical performance of the systems.

They import the bidirectional reflectance distribution function (BRDF) and bidirectional transmittance distribution function (BTDF) results into the LightTools or Zemax simulation software to size an optical system and obtain results close to industrial reality.

  • Volume diffusion measurement for opaque or translucent materials:
volume diffusion optic measurement

Commercial references or samples can be measured through the Bidirectional Scattering Distribution Function (BSDF). This measurement also records how light is scattered in transmission via the BTDF and in reflection via the BRDF.

BRDF BTDF optics

Experts charge the material with diffusing particles such as titanium dioxide. They can then provide the loading rate in a defined material such as PC or PMMA and adjust it according to the performance to be achieved.

  • Measurement of surface diffusion for grained and textured materials :
surface diffusion optique

Similar to volumetric diffusion, the BSDF of commercial references or custom samples can be measured. PISÉO has VDI 3400 and Mold-Tech injection mold texturing references for aluminum, PC, PMMA and silicone optics. We thus support our customers in the production of their textured molded part.

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]]> Radiometric measurements in the UV https://piseo.fr/en/optical-laboratory/photometry-laboratory/radiometric-measurements-in-the-uv/ Tue, 29 Sep 2020 14:37:17 +0000 https://piseo.fr/?p=4413 Ultraviolet (UV) radiation is included in the part of the light spectrum ranging from 200nm to 380nm. They are more energetic than the radiation emitted in the visible. Also, depending on the wavelength used, their applications can be very varied: disinfection, polymerization, tanning … However, these rays are dangerous for the human body and can […]

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]]> Ultraviolet (UV) radiation is included in the part of the light spectrum ranging from 200nm to 380nm. They are more energetic than the radiation emitted in the visible. Also, depending on the wavelength used, their applications can be very varied: disinfection, polymerization, tanning …

However, these rays are dangerous for the human body and can deteriorate materials. It is therefore necessary to have a good understanding of UV radiation by carrying out measurements on the light sources and devices that integrate them.

spectre UV

UV measurements

Radiometric measurements carried out in a reliable and impartial manner thus make it possible to know precisely the radiation emitted and to determine the performance of devices operating in the UV.

In this context, the PISEO lab offers the following radiometric measurements and analyzes:

– measurement of the UV-A, UV-B and UV-C spectrum

– irradiance measurement (Wopt / cm2) on a surface at a given distance of 250nm to 380nm

– mapping of irradiance on a surface at different distances

– calculation of energy doses (J / cm2) at a given distance and time

Equipments :

– UV-C power probe and optometer Gigahertz optik (UV-3726-4 / X1-1 V-02): 250nm-290nm

– CAS 140D Instrument System spectroradiometer: 300nm-1100nm

– OST 300 Everfine radiometric bench: 200nm-1600nm

UV measurements

“UV-C LEDs at the time of Covid-19”

Following the exceptional crisis linked to the appearance of Covid-19 (Coronavirus), disinfection to fight contagion has become a real subject. Moreover, UV-C radiation can destroy this virus, just like other coronaviruses.

Thus, PISEO has published a report providing a complete description of the UV-C LED technology, its implementation in systems, market and much more.

PISEO experts present in particular:

– an analysis of the offer of UV-C LED manufacturers,

– the performance and price evolution prospects of these light sources,

-the methodology to be followed to design and qualify efficient disinfection devices,

-a deep analysis of the applicable regulations,

-an analysis of the application needs expressed in terms of doses to be applied according to the microorganisms to be destroyed.

UV-C LED

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]]> “À la carte” tests https://piseo.fr/en/optical-laboratory/photometry-laboratory/a-la-carte-tests/ Mon, 06 Jul 2020 14:02:26 +0000 https://piseo.fr/?p=2845 Are you currently developing or modifying an optical or LED lighting product and want to quickly carry out series of tests for its development?We offer to carry out tests (optical, photometric, etc.) à la carte in your presence to carry out a maximum of tests in a minimum of time. Nothing is easier : Laboratory […]

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]]> Are you currently developing or modifying an optical or LED lighting product and want to quickly carry out series of tests for its development?
We offer to carry out tests (optical, photometric, etc.) à la carte in your presence to carry out a maximum of tests in a minimum of time.

Nothing is easier :

  • You make an appointment for a day or half-day of laboratory tests with our staff and in your presence.
  • You come on the appointed day with your samples to be tested and have all the tests you want carried out by our staff.
  • You can therefore interact directly based on the test results and vary the parameters you want.
test lab

Laboratory equipment at your disposal

  • Goniophotometry
  • Spectral and colorimetric analyzes under variable current and temperature conditions
  • Thermal analyzes using IR camera and thermocouples
  • Electrical analysis
  • Luminance maps

These tests do not allow you to submit an accredited report.

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]]> Characterization of phosphorescent devices https://piseo.fr/en/optical-laboratory/characterization-of-phosphorescent-devices/ Mon, 06 Jul 2020 09:59:30 +0000 https://piseo.fr/?p=2780 Phosphorescent materials have the particularity of emitting light during a period of time which depends on their nature and duration of exposure to light radiation. PISEO has test facilities to characterize the luminance, its decreasing over time, the persistence time, the spectral composition and the color of products incorporating phosphorescent materials (textiles, paints, concretes …). […]

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]]> Phosphorescent materials have the particularity of emitting light during a period of time which depends on their nature and duration of exposure to light radiation.

PISEO has test facilities to characterize the luminance, its decreasing over time, the persistence time, the spectral composition and the color of products incorporating phosphorescent materials (textiles, paints, concretes …).

These characterizations allow PISEO’s customers to know precisely the performance of their products and thus to value them.

Measurements

To emit light, a product loaded with luminescent material must have been previously exposed to a dose of light (energy).This dose can be provided by sunlight or by an artificial light source whose emission spectrum and duration should be known to produce the expected visual effect on the product (luminance, color, remanence).

In addition to the applied radiation dose, the chemical composition and quantity of the phosphorescent materials contained in the products will be determinant for the desired effect.

PISEO has expertise in optics to develop specific artificial light sources based on monochromatic LED able to produce the energy radiation necessary to activate the phosphorescent phenomenon. In particular, PISEO has developed a test bench that combines a module equipped with UV LED and D65 LED and associated with a luminance camera. This device allows to simulate the light of day and to apply to the samples tested the desired energy doses and then to characterize the variation of the brightness levels (luminance) over time up to “the extinction”.

The device allows to carry out product benchmarks with a regular recording of the measure luminance after the application of variable energy doses according to the needs of the Customer.

Thanks to their knowledge of luminescent materials and the characterization of illumination systems, PISEO experts can also assist the Customer in defining the test program, in interpreting the results obtained and, if necessary, in improving the performance of the tested products through consulting on material formulation.

phosphorescent

Note: Luminous decreasing are always compared regardless of the perception of the eye, but a red emission will be perceived much shorter than a green emission. The measurement of the luminance makes it possible to account for this physiological aspect. The luminance measurements realized by PISEO are based on the French standard NF X 08-050-1 Part 1.

Spectral and colorimetric measurements

Spectral and colorimetric measurements can also be done on samples using an Instrument Systems CAS 140 spectroradiometer.

Equipments

WESTBORO PHOTONICS 5Mpx P501F camera:

Westboro camera

Instrument Systems CAS 140 Spectroradiometer :

Luminescent material measurements
Benchtop spectrophotometer

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]]> Photobiological risk evaluation NF EN62471 https://piseo.fr/en/optical-laboratory/photometry-laboratory/photobiological-risk-evaluation-en62471/ Mon, 06 Jul 2020 07:58:59 +0000 https://piseo.fr/?p=2759 The assessment of the photobiological risk (NF EN62471 & IECTR 62778) of light sources and devices using them is one of the mandatory requirements imposed by the European Commission to ensure the safety of products and people. Required by various European directives, the assessment of photobiological risk is part of the CE marking of products […]

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]]> The assessment of the photobiological risk (NF EN62471 & IECTR 62778) of light sources and devices using them is one of the mandatory requirements imposed by the European Commission to ensure the safety of products and people. Required by various European directives, the assessment of photobiological risk is part of the CE marking of products marketed in Europe.

All products are concerned: lighting, toys, medical devices, etc.
Manufacturers and marketers of products integrating light sources must therefore assess the level of associated risk according to standard NF EN 62471 and, where applicable, taking into account the additional requirements of IEC TR 62778 for lighting devices. LED lighting.

The safety standards for luminaires, LED modules and LED lamps refer to this last document for the assessment of the risk to blue light.

Accredited for measurements according to NF EN62471 and IEC TR 62778

The protocol implemented by PISEO complies with the NF EN 62471 standard. This allows the classification of the product studied according to 4 risk groups ranging from 0 to 3 for lighting devices but also LED optical systems.

The term “photobiological hazard” refers to the potential of LED light to injure the eye, particularly at the extreme ends of the visible spectrum.

On the blue end of the visible spectrum, the risks are with UV light, while on the red side it will be more with infrared light.

Several criteria are taken into account for the measurement result and in particular those concerning the risks for the skin and the eyes: exposure of the skin, exposure of the surface of the eye (cornea, conjunctiva and lenses), as well as the exposure of the retina in the posterior part of the eye.

risque photobiologique NF EN 62471

Measuring equipment to assess photobiological risk

EVERFINE OST-300 radiometric bench

The measurements are carried out on a radiometric measurement bench entirely dedicated to photobiological risk assessment.

This bench can perform all the measurements required by the NF EN62471 and IEC TR62778 standards for ultraviolet, visible and infrared radiation.

PISÉO has chosen to work only with state-of-the-art equipment whose manufacturers enjoy worldwide renown.

Our measuring equipment is frequently calibrated, checked and calibrated. In addition, they are implemented by qualified operators in a controlled environment (temperature, humidity, etc.). All of these parameters together ensure correct and reliable test results.

As part of the accreditation, the bench is calibrated using standard light sources connected to the International System.

Evolution in the assessment of photobiological risk with the IEC 62471-7 standard

Evolution in the assessment of photobiological risk with the IEC 62471-7 standard
The IEC 62471-7 standard evolves the risk assessment method for lighting fixtures by providing a different classification from the IEC 62471:2006 standard. It concerns light sources emitting in the visible and will eventually replace IEC TR 62778 which is of regulatory application within the framework of the IEC 60598-1 safety standard. PISÉO dedicates a complete article to this subject.

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]]> Characterization of displays and luminous surfaces https://piseo.fr/en/test-lab/characterisation-of-displays-and-luminous-surfaces/ Mon, 06 Jul 2020 07:47:28 +0000 https://piseo.fr/?p=2752 On entend par “écran” toute surface lumineuses telle que les enseignes lumineuses, claviers rétro-éclairés, pictogrammes, boutons lumineux, marquages phosphorescents, signalétique.. Ces surfaces lumineuses présentent des caractéristiques photométriques et colorimétriques mesurables. Par conséquent, caractériser un écran au moyen d’équipements adaptés permet de quantifier sa performance visuelle et de vérifier sa conformité avec la réglementation. PISÉO peut […]

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]]> On entend par “écran” toute surface lumineuses telle que les enseignes lumineuses, claviers rétro-éclairés, pictogrammes, boutons lumineux, marquages phosphorescents, signalétique..

Ces surfaces lumineuses présentent des caractéristiques photométriques et colorimétriques mesurables.

Par conséquent, caractériser un écran au moyen d’équipements adaptés permet de quantifier sa performance visuelle et de vérifier sa conformité avec la réglementation.

PISÉO peut ainsi vous proposer :

  • des mesures de luminance
  • des cartographies des luminances en 2D,
  • des mesures de distribution spectrale et colorimétriques,
  • ainsi que des mesures de flicker, réalisées en conformité avec les normes internationales.

Cartographie de luminance en 2D sur écran

La luminance, intensité lumineuse par unité de surface exprimée en cd/m², est une des caractéristiques clés du ressenti visuel lorsque l’on observe une source de lumière.

Ainsi, plus la luminance sera élevée et contrastée avec la luminosité ambiante, plus la source de lumière sera susceptible de produire un sentiment d’éblouissement et donc un inconfort visuel.

Cela est particulièrement vrai avec les appareils d’éclairage à LED. En effet, les LED peuvent présenter des luminances élevées (> 5000 cd/m²), surtout celles dont la surface d’émission lumineuse est très petite et ainsi directement visibles.

Outre la luminance ponctuelle, on s’intéressera également à luminance moyenne, à l’uniformité des luminances et aux contrastes sur l’ensemble de la surface lumineuse considérée. C’est le cas des écrans (TFT, OLED) et des autres dispositifs tels que les claviers rétro-éclairés, les interfaces homme-machine (IHM), les pictogrammes, les bandes réfléchissantes, les boutons lumineux, les pictogrammes…,

Mesure écran

Dans ce cas la caractérisation des luminances en 2D au moyen d’une caméra de luminancemétrie sera particulièrement adaptée pour mesurer de manière efficace et fiable les performances de toute surface lumineuse.

Elle permet notamment de réaliser toutes les mesures des caractéristiques de performance des normes et standards internationaux tels que IDMS, ISO 9241-305, ISO 3864-4, EN 1838…

Cet équipement qui dispose de différents objectifs et d’un logiciel d’analyse particulièrement élaboré, nous permet de tester de manière fiable et rapide vos dispositifs lumineux et de vous fournir des rapports d’essais contenant les caractéristiques suivantes :

  • Luminance ponctuelle
  • Luminance moyenne par zone définie
  • Uniformité dans la zone
  • Contrastes entre différentes zones
  • Pixels morts
  • Réflexion
  • MTF

Les performances optiques de l’œil humain en terme de résolution et de sensibilité aux contrastes peuvent être appréciées par une seule et même fonction : la Fonction de Transfert de Modulation  (FTM) en français ou «Modulation Transfert Function – MTF » en anglais. C’est une fonction qui donne une présentation synthétique du contraste et de la résolution d’un système optique.

Le laboratoire de PISÉO réalise ainsi des mesures de cette donnée qui se révèle très importante pour évaluer la qualité de tout système d’imagerie.

Distribution spectrale et mesures colorimétriques

Les mesures de distribution spectrale et colorimétriques d’écrans et de surfaces lumineuses sont réalisées de manière ponctuelle au moyen d’un spectroradiomètre et d’une sonde déportée que l’on vient appliquer sur la surface à caractériser.

Aussi, l’utilisation d’un spectroradiomètre permet une mesure de l’ensemble du spectre lumineux émis puis par calcul de déterminer de manière de manière extrêmement précise les caractéristiques colorimétriques mesurées (point de couleur).

Équipements de mesure

  • Sphères intégratrices Instrument Systems 2m et GL Optik 50cm
  • Spectroradiomètre Instrument Systems CAS 120 et 140CT

Mesures de flicker sur écran

Le flicker caractérise le scintillement des écrans ou de toute source de lumière. A certaines fréquences, il peut donc être perceptible par l’œil humain.

Ce phénomène dépend de la conception électronique et s’avère être une caractéristique discriminante de la qualité du système.

Doté de l’équipement adéquat, le laboratoire de PISÉO vous propose des mesures de flicker sur les écrans en accord avec les normes internationales IDMS, ISO 9241-305, IEC 62288

Équipements de mesure pour écran

  • Photomètre Westboro Photonics PF 501 A 5Mpx, dynamique de 0.01cd/m² jusqu’à 100 Mcd/m²
  • Source de luminance
  • Flickermètre Admesy Asteria
  • Objectifs 50mm, grand angle, macro
  • Logiciel de traitement et d’analyse Photometrica
mesure luminance et uniformité

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