The First

International Proficiency Testing Conference

Sinaia, România 11th − 13th October, 2007

300

SC OPTOELECTRONICA – 2001 SA UV, VIS, IR OPTICAL TESTING

LABORATORY

Necsoiu Teodor, Brindus Comanescu and Iulia Racicovschi SC Optoelectronica – 2001 SA, Strada Atomistilor Nr. 409, Magurele, Judetul Ilfov,

Romania, 077125 tnecsoiu@optoel.com, brindus@optoel.ro, iulia@optoel.ro

Abstract It is made o short presentation of SC Optoelectronica - 2001 SA. Due to the continuous development and miniaturization of optics and optics devices, it was necessary to measure and compare optical parameters. The laboratory is organized and carries out its activity on the rules of SR EN ISO 17025:2005. It was designed and implemented a Quality Management System, that represents the base of performance of all activities. The main tested parameters are: ●EFL-effective focal length and BFL-back focal length for lenses;

●Optical system field of view, Limits: (-60°, +60°); ●Magnification (grossisment);

●Astigmatism; ●Contrast; ●Image quality evaluation; resolution, image distortion, MTF modulation transfer function in real time, spherical and chromatic aberrations, field curvature. General objective of laboratory consists in developing of capacity in certification and evaluation domain for assuring the implementation of European specific legislation transposed in national legislation. The laboratory carries out optical components and optical equipment/devices testing in order to apply on them CE mark by accredited organisms of product certification as a result of them collaboration with laser beam testing laboratory. Also, it is presented both the testing equipment and their main specifications, without mentioning types and companies and the results obtained by the laboratory in carrying out tests and measurements.

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Key words Optics, optical, laboratory, quality management system, measuring, testing, image, quality, evaluation, parameter, physics, inspection, certification 1 A SHORT PRESENTATION OF THE SOCIETY SC OPTOELECTRONICA – 2001 SA is o private company, with the main activity object research &development in optoelectronic field. The main activities of the society are: research and technological development and innovation in physics, advanced electronics, optoelectronic devices development for special applications, advanced technological developments in the optoelectronic domain. Besides this, society has a small fabrication line for optoelectronic devices (night vision devices, lasers and laser devices, false document analyzers, medical equipment) destined to the civilian and military applications. Also, society carries out thermal services, optical and laser testing, mechanical CNC processing services. SC Optoelectronica SA has implemented an ISO 9001:2001 certified Quality System. 2 GENERALITIES Optics is a domain that appeared and developed long time ago, first as simple geometric optics which has remained of the same importance and has taken a significant place in the time of the antiquity philosophers. Optics is the branch of physics that studies the physical properties of light. The evolution on the superior level of the optics knowledge is in tight correlation with design, construction and use of new optics apparatus, especially optoelectronic devices.Thus, it was developed new branches in optics. For example, the integrated optics. The goal of integrated optics is to develop miniaturized optical devices of high functionality on a common substrate. The state-of-the-art of integrated optics is still far behind its electronic counterpart. Today, only a few basic functions are commercially feasible. However, there exists a growing interest in the development of more and more complex integrated optical devices. In the same time it was developed the spectroscopy as an application of lasers, radiation physics and optics. Due to the continuous development and miniaturization of optics and optics devices, it was necessary to measure and compare optical parameters. Thus, optics apparatus construction and use of optical tests have extended researches in optics that lead on discovering of new principles and laws and understanding better the optics applications. As we know, in our country, in present, among the accredited laboratories there are not any laboratory, having as activity object optical testing in UV, VIS, IR range. Although, some of companies which have as the activity object optoelectronics, optics and laser production carry out optical tests for their internal needs based on internal rules, technical specifications, national or international standards. In 2005 year, SC Optoelectronica 2001 SA presented to RENAR the accreditation documentation for carrying out of a number of optical tests, strict necessary for the evaluation of performances of optical components and systems. Already last year

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S C Optoelectronica 2001 SA presented to RENAR the accreditation documentation for extending testing range. In the future, we take into consideration the possibility of extending range with spectrophotometric measurements. It is put accent on developing testing methods for evaluating optical components and systems quality. The laboratory has developed the stand calibration and evaluation methods following to cover a broad measuring range for plastic lenses beginning with 1 mm diameter, resolution and contrast very low to more than 40 mm and focal length up to 1000 mm. It is possible to measure digital photo objectives with plastic optical components of very low resolution and contrast and TV corrected objectives with variable focal lenses of very high resolution and contrast used in image acquisition and microscope objectives. It is necessary to verify optical component and system quality both during technological process and overall at the end of process. It is put accent on image quality evaluation; resolution, image distortion, MTF modulation transfer function in real time, spherical and chromatic aberration, field curvature. 3 OPTICAL TESTING SERVICES FOR LENSES AND OPTICAL SYSTEMS The laboratory is organized and carries out its activity on the rules of SR EN ISO 17025:2005. Taking into consideration the requirements of standard it was designed and implemented a Quality Management System, that represents the base of performance of all activities. The main objective of the company and of the laboratory in the quality domain is complying with all contractual requirements of clients, keeping agreed schedule, offering attractive prices, all of them based on respect and sincerity relative to client. The general objectives of the company and laboratory in the quality politics are:

●Increasing of client satisfaction; ●Increasing of company prestige and creation of an excellence image; ●Increasing of efficiency and operational efficiency of all activities; ●Continuous improvement of the delivered services;

Our testing offer is first useful in research and development (R&D) activities to test designed lenses to see if they are according to the requirements of a new application. The optical testing could diagnose image problems from the prototype phase for a lens or optical system according to the conclusions and the results obtained by measuring them parameters.Thus, it is possible to optimize the parameters of the optical systems. Another destination of optical testing services could be an independent evaluation in inspection and certification of the lenses or optical devices for market or for clients. Below, we mention some of possible tests carried out in optical testing laboratory: ● EFL-effective focal length and BFL-back focal length for lenses.The measuring uncertainty is 0.1%; EFL/ f; BFL/ff: (-20mm, +500 mm); with possibilities of extending the range, as follows: -1… -500mm; +1…+500mm and to 1000mm. (with analogical measurement method);

●Optical system field of view, Limits: (-60°, +60°); ●Magnification (grossisment);

●Astigmatism; ●Contrast;

Teodor Necsoiu, Brindus Comanescu, Iulia Racicovschi: SC Optoelectronica – 2001 SA UV, VIS, IR Optical Testing Laboratory

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● Image quality evaluation; resolution, image distortion, MTF modulation transfer function in real time, spherical and chromatic aberrations, field curvature. The lens and optical system testing is the faster way to solve a image problem even when the contrast and resolution are very low. By our manual testing system of the lenses it is assured a testing platform with a high coefficient of reliability. The system is based on both the testing tricks and the quantitative and qualitative measurements for assuring clear feedback of lens quality. It is possible to test the lenses even in the design stage. To determine resolution limits, the design data are introduced in an image evaluation program (effective focal length, magnification, f-number/exit pupil diameter for afocal optical systems). Thus, it is possible to optimize manufacturing process of lenses and optical systems. Image analysis of lenses and optical systems tested with USAF 1951 target cross reticle and specific software permit:

● Display in real time of monochrome image of 1066.24 µm x 799.68 µm, With 4 X magnification or of 426.24 µm x 319.68 µm with 10 X magnification, 20 X , 30 X;

● Set over and zoom in order to overcome discreet image element ● Image load, measuring image save, record storage, information

transmission in a very shot time; ● Real time measuring: contrast, diagram of line and point spread, diagram

of cross section and histogram; random object position in image analysis and evaluation with accuracies of 0.069 µm; 0.15 µm; 0.7 µm, depending of the characteristics of tested lens or optical system; diagrams of focal length or magnification for optical systems, versus time. The laboratory offers ideal services for testing and inspection in order to certify optical components, optical systems, optoelectronic equipment a.s.o. The laboratory will extend its measuring range with spectrophotometric tests/measures, as follows:

● UV, VIS, IR spectra records with possibilities of sample comparing in relation to a reference;

● Transmittance, absorbance and reflectance measuring versus wave length; ● Quantitative and qualitative evaluation of a sample and its qualitative comparison with a reference of the same type evaluating directly the concentration and composition difference between sample and reference.

● Colour comparison, in xyz planes, between a sample and a reference in order to estimate the colour difference and eventually colour tone difference. In the same time, our UV, VIS, IR optical testing laboratory is able to carry out radiometric measurement, especially for thermal cameras and pyrometers. 4 TESTING/MEASURING EQUIPMENT For carrying out the tests, the laboratory is endowed with the up-to-date testing equipment, that exists on the international market. There are three major benches for measuring optical parameters of the optical components and devices. One of them has the possibility to measure optical parameters in analogue mode. With this bench it is possible to carry out the following measurements: effective focal

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length, back focal length, resolution limits, magnification (grossisment), field of view, exit and entrance pupils. The other both ones measure all the above optical parameters. They are provided with specific softwares assuring a very high accuracy level of the measurements. For most of the parameters the uncertainty of measuring is better than 0.1 %. Also, the laboratory has some reference materials as lenses with known parameters. Having the possibility to measure optical parameters with more methods and using reference materials we assure a very high level of confidence for our clients. Spectrophotometric calitative analysis are assured by modern UV-VIS-IR spectrophotometers, provided with specialized softwares. 5 THE CARRIED OUT TESTS IN THE LABORATORY In the laboratory were carried out the internal tests for a series of reference optical components and systems existing in society. At the request of scientific research teams, from our society, it were made tests for characterizing their working optical components and devices. Thus, there were carried out all measurements described above. Tests carried out had as aim to verify the testing procedures and testing working instructions. It were made comparative tests for being sure that testing methods are valid. Below, it is presented a testing arrangement for some parameters with one of the bences.

Figure 1 Test arrangement for optical parameter measurements For example, below it is presented a diagram of MTF for a lens

Teodor Necsoiu, Brindus Comanescu, Iulia Racicovschi: SC Optoelectronica – 2001 SA UV, VIS, IR Optical Testing Laboratory

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Figure 2 Diagram of MTF for a lens REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9]

Moisil G., Curatu E., Optica-teorie si aplicatii, Editura tehnica, Bucuresti , 1986 Dodoc P., Teoria si constructia aparatelor optice, Editura tehnica, Bucuresti,1989 Calculul si constructia aparatelor optice – Indrumar de laborator, Institutul Politehnic Bucuresti, 1988 SR EN ISO/CEI 17025:2005 – Cerinte generale pentru competenta laboratoarelor de incercari si etalonari SR ENV 13005:2003 Ghid pentru exprimarea incertitudinii de masurare User Manual: “OCK” - Optical testing bench User Manual “Optic Studio” – Optical testing equipment and bench User Manual “Optispheric” – Testing equipment User Manual “V 570 Spectrophotometer”