Optical flat

Optical Flat Resurfacing

Optical flats become worn and abraded from use and accuracy is lost. This degradation in performance is due to a decrease in the distinctness of the interference pattern, and to a change in figure caused by scratches on either side of the optical flat. Resurfacing or re-polishing the surface of an optical flat back to its original accuracy can be less costly than replacement. Advanced Optics maintains an optical flat refinishing service with a fast turnaround time.
Whether you require custom optical fabrication or one of our many off-the-shelf flats, call today for a competitive quote!

Optical Flat Interpretation

An optical flat is a piece of glass that has been precision polished to a specific flatness on one or both sides and is used as a reference (test plate) against which the flatness of an unknown surface can be compared. In practice, an optical flat can be used to test and certify metal or glass surfaces that have been lapped or polished such as metal rings or seals, optical mirrors and optical windows, prisms, filters and more. A single sided optical flat (single surface optical flat) is polished on only one side and the opposing side is generally left clear, but not precision polished. A double sided optical flat (dual surface optical flat) is precision polished on both sides and may be used as an optical window.
Optical flats are polished to a known flatness and used in conjunction with a monochromatic light source. The optical flat is placed on top of the work to be tested under a monochromatic light of a specific wavelength, typically He-Ne which has a wavelength of 632.8nm and is equivalent to 0.000024 inches per wave. An interference (fringe) pattern of light and dark bands are formed due to the air gap between the work surface and the optical flat. The change in thickness of the air gap or wedge shows the direction and shape of the interference bands. The curvature and distance between bands determines how flat the work surface is compared to the known surface of the optical flat.
To determine the surface flatness of a test piece (work surface) using the interference pattern formed by an optical flat, gently place the optical flat on top of the work piece. Both the working surface of the test piece and the optical flat should be clean and free of dust. Care should be taken to not slide the optical flat across the surface of the part being tested as it may cause damage (scratches) to the optical flat. Scratches or damage to the surface of the optical flat can cause it to become less flat and therefore affect the results of the test. Next use a soft object, such as the new eraser of a pencil, to apply pressure to various points across the surface of the optical flat. Applying gentle pressure will reduce the air gap between the optical flat and the working surface of the part being tested. As the air gap is reduced, a fringe pattern (light and dark bands) will appear. Continue to apply light pressure to spread the fringes so that only a few are visible. Then imagine two straight and parallel lines, one between the ends of any one fringe and the other at the top of that same fringe. The number and curvature of fringes located between the two lines can be used to determine flatness.

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Optik tekis sirtni qayta tiklash
Foydalanish natijasida optik yassilar eskiradi va yiqilib ketadi va aniqlik yo'qoladi. Ishlashning bunday pasayishi interferentsiya naqshining aniqligining pasayishi va optik tekislikning har ikki tomonidagi tirnalganligi sababli shaklning o'zgarishi bilan bog'liq. Optik yassi yuzasini asl aniqligiga qaytarish yoki qayta parlatish almashtirishdan ko'ra arzonroq bo'lishi mumkin. Advanced Optics tez aylanish vaqti bilan optik tekis tozalash xizmatini qo'llab-quvvatlaydi.
Sizga maxsus optik ishlab chiqarish kerak bo'ladimi yoki bizning ko'p sotiladigan kvartiralarimizdan biri kerakmi, raqobatbardosh narx uchun bugun qo'ng'iroq qiling!
Optik tekis talqin
Optik yassi – bu bir yoki ikki tomondan ma'lum bir tekislikka qadar aniq sayqallangan va noma'lum sirt tekisligini solishtirish mumkin bo'lgan mos yozuvlar (sinov plitasi) sifatida ishlatiladigan shisha bo'lagi. Amalda, optik yassi metall halqalar yoki muhrlar, optik oynalar va optik oynalar, prizmalar, filtrlar va boshqalar kabi laklangan yoki parlatilgan metall yoki shisha yuzalarni sinash va sertifikatlash uchun ishlatilishi mumkin. Bir tomonlama optik yassi (bitta sirtli optik tekis) faqat bir tomonda silliqlangan va qarama-qarshi tomon odatda aniq qoldirilgan, ammo aniqlik bilan silliqlanmagan. Ikki tomonlama optik yassi (ikki yuzali optik tekis) har ikki tomonda ham nozik silliqlangan va optik oyna sifatida ishlatilishi mumkin.
Optik yassilar ma'lum tekislikka sayqallanadi va monoxromatik yorug'lik manbai bilan birgalikda ishlatiladi. Optik yassi ma'lum bir to'lqin uzunlikdagi monoxromatik yorug'lik ostida sinovdan o'tkaziladigan ishning ustiga qo'yiladi, odatda He-Ne to'lqin uzunligi 632,8 nm va to'lqin boshiga 0,000024 dyuymga teng. Ish yuzasi va optik yassi orasidagi havo bo'shlig'i tufayli yorug'lik va qorong'i bantlarning interferentsiya (chekka) naqshlari hosil bo'ladi. Havo bo'shlig'i yoki takoz qalinligining o'zgarishi interferentsiya bantlarining yo'nalishi va shaklini ko'rsatadi. Bantlar orasidagi egrilik va masofa ish yuzasining optik tekislikning ma'lum yuzasiga nisbatan qanchalik tekisligini aniqlaydi.
Optik yassi hosil qilgan interferentsiya naqshidan foydalanib, sinov buyumining (ish yuzasi) sirt tekisligini aniqlash uchun optik tekislikni ish qismining ustiga yumshoq qilib qo'ying. Sinov qismining ishchi yuzasi ham, optik tekisligi ham toza va changdan tozalangan bo'lishi kerak. Optik tekislikni tekshirilayotgan qismning yuzasi bo'ylab siljitmaslik uchun ehtiyot bo'lish kerak, chunki u optik tekislikka zarar etkazishi (tirnalgan) bo'lishi mumkin. Optik yassi yuzasining tirnalgan yoki shikastlanishi uning kamroq tekis bo'lishiga olib kelishi mumkin va shuning uchun sinov natijalariga ta'sir qiladi. Keyinchalik, optik tekisning yuzasi bo'ylab turli nuqtalarga bosim o'tkazish uchun qalamning yangi silgisi kabi yumshoq narsadan foydalaning. Yumshoq bosimni qo'llash, sinovdan o'tkazilayotgan qismning optik tekisligi va ishchi yuzasi orasidagi havo bo'shlig'ini kamaytiradi. Havo bo'shlig'ining kamayishi bilan chekka naqsh (engil va qorong'i bantlar) paydo bo'ladi. Faqat bir nechtasi ko'rinadigan qilib, chekkalarni yoyish uchun engil bosimni qo'llashda davom eting. Keyin ikkita to'g'ri va parallel chiziqni tasavvur qiling, ulardan biri har qanday chekkaning uchlari orasida, ikkinchisi esa o'sha chetning tepasida. Yassilikni aniqlash uchun ikkita chiziq o'rtasida joylashgan chekkalarning soni va egriligidan foydalanish mumkin

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Selectional of an Optical Flat

Optical flats can be made of several low expansion materials such as fused silica, fused quartz. Zerodur© or Clearceram© Fused silica and fused quartz provide low thermal expansion and are ideal for high wear applications. Zerodur© and Clearceram© are glass-ceramic materials with extremely low thermal expansion and are an ideal choice for applications where temperature fluctuation is a concern. BOROFLOAT©33 may also be considered as a less expensive alternative for test plates.

An optical flat must be more accurate (flatter) than the surface of the work or piece being tested. For example, if the surface being tested is flat to ¼ wave or ½ of a light band, the optical flat used to determine if the work or test piece is flat should be 1/10 wave or 1/5 of a light band. The optical flat should be larger than the part being tested so that an accurate reading of the entire work surface is obtained.

Optical flats come in many different accuracies, but most commonly ¼ wave, 1/10 wave and 1/20 wave. In addition to describing the accuracy of an optical flat in terms of waves (as above) accuracy may be specified in terms of light bands, microinches, fringes or inches. The table below summarizes how the accuracy of an optical flat may be specified.

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Optik tekislikni tanlash

Optik kvartiralar eritilgan kremniy, eritilgan kvarts kabi bir nechta past kengayish materiallaridan tayyorlanishi mumkin. Zerodur© yoki Clearceram© Eritilgan silika va eritilgan kvarts past issiqlik kengayishini ta'minlaydi va yuqori aşınma ilovalari uchun idealdir. Zerodur© va Clearceram© juda past issiqlik kengayishiga ega shisha-keramika materiallari bo'lib, haroratning o'zgarishi tashvishlanadigan ilovalar uchun ideal tanlovdir. BOROFLOAT©33 ham sinov plitalari uchun arzonroq alternativ sifatida ko'rib chiqilishi mumkin.

Optik yassi sinovdan o'tkazilayotgan ish yoki buyumning yuzasiga qaraganda aniqroq (tekisroq) bo'lishi kerak. Misol uchun, agar sinovdan o'tkazilayotgan sirt ¼ to'lqin yoki yorug'lik chizig'ining ½ qismi tekis bo'lsa, ish yoki sinov qismi tekis ekanligini aniqlash uchun ishlatiladigan optik tekislik yorug'lik chizig'ining 1/10 to'lqini yoki 1/5 qismi bo'lishi kerak. Optik tekislik sinovdan o'tkazilayotgan qismdan kattaroq bo'lishi kerak, shunda butun ish yuzasining aniq o'qilishi olinadi.

Optik tekisliklar juda ko'p turli xil aniqlikda keladi, lekin ko'pincha ¼ to'lqin, 1/10 to'lqin va 1/20 to'lqin. Optik yassi to'lqinlar bo'yicha aniqligini tavsiflashdan tashqari (yuqoridagi kabi) yorug'lik chiziqlari, mikrodyuymlar, chekkalar yoki dyuymlar bo'yicha aniqlik belgilanishi mumkin. Quyidagi jadvalda optik kvartiraning aniqligi qanday aniqlanishi mumkinligi haqida umumiy ma'lumot berilgan.

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Optical flats are commonly round in shape. However, depending on their application, custom shapes and may be required. Our optic capabilities also include crafting custom shapes including; square, rectangular, beveled and truncated optical flats. We also have the ability to drill custom holes and can provide coatings to increase the interference (fringe) pattern. In addition, we offer custom wooden storage cases for the protection of the optical flat when not in use.

Keep in mind, understanding your application can help you to select the right optical flat without over specifying your requirements thereby saving you time and money. Choosing the appropriate material, defining the correct accuracy and determining whether the flat should be polished on one or both sides should be considered. If you are still uncertain as to how to specify the corre features ct optical flat, Advanced Optics has over 50 years of experience and can help you define your requirements and wisely choose the correct optical flat for your application.
An optical flat, also known as a test plate or a reference flat, is used to test the flatness of glass or metal surfaces that have been lapped. Wen our reference flat is placed in contact with a glass or metal surface that is being tested, interference fringes would be created. The pattern of the fringes indicates the flatness level of the test piece.
Custom Scientific optical flats are used around the world by optical machine shops to test their finished parts. Our flats are also used by Quality Control inspection teams to test and certify the polish of finished parts.
These optical flats can also be used as substrates for precision mirrors. Such mirror coatings are typically, Silver, Gold, or a custom dielectric high-reflector coating. You can deposit this coating, or we can do it – contact us for a quote. Our standard optical flats that are written in the tables above and have a one-week delivery are designed primarily for contact testing and consequently have a somewhat relaxed cosmetic quality (80-50 scratch-dig). While this is quite suitable for contact testing, if you intend to use these flats as a mirror substrate, you may need a better surface quality which we can definitely provide – please contact us directly for information about that.
If you are looking for precision windows where you can cont Aluminum rol the transmitted wavefront accuracy to a level of lambda/4 or better, then we would need to quote that on a custom basis – Please contact us for such a quote. These optical flats are not intended to be used as precision windows (that is, better than around 1 x lambda per inch in transmission) because even though the surface(s) are polished to a high precision, the bulk fused quartz material between the surfaces has a relaxed control of refractive index homogeneity. This means that even though light reflecting off the surfaces would undergo a very small degradation in wavefront, light transmitting through the window would undergo a significantly more wavefront degradation, typically around 3 or 4 x lambda per inch. Please note that the degradation in transmitted wavefront is not visible to the eye – it would look like an excellent window – if you were to measure it on an interferometer the readings would show the wavefront degradation. If you need a precision window which has good transmitted wavefront accuracy, please contact us and we would provide a quote. We do precision windows routinely, but not in a stock program like the optical flats.

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Optik kvartiralar odatda yumaloq shaklga ega. Biroq, ularning qo'llanilishiga qarab, maxsus shakllar va talab qilinishi mumkin. Bizning optik imkoniyatlarimiz shuningdek, maxsus shakllarni yaratishni o'z ichiga oladi, jumladan; kvadrat, to'rtburchaklar, qiyshiq va kesilgan optik yassi. Bundan tashqari, biz maxsus teshiklarni burg'ulash qobiliyatiga egamiz va interferentsiyani (sochka) naqshini oshirish uchun qoplamalar bilan ta'minlay olamiz. Bundan tashqari, biz foydalanilmayotganda optik kvartirani himoya qilish uchun maxsus yog'och saqlash qutilarini taklif qilamiz.

Yodda tuting, arizangizni tushunish sizning talablaringizni ko'rsatmasdan turib, to'g'ri optik kvartirani tanlashga yordam beradi va bu sizga vaqt va pulni tejaydi. Tegishli materialni tanlash, to'g'ri aniqlikni aniqlash va kvartirani bir yoki ikki tomondan silliqlash kerakligini aniqlash kerak. Agar siz hali ham ct optik kvartiraning to'g'ri xususiyatlarini qanday belgilashni bilmasangiz, Advanced Optics 50 yildan ortiq tajribaga ega va sizning talablaringizni aniqlashga va ilovangiz uchun to'g'ri optik kvartirani oqilona tanlashga yordam beradi.
Sinov plitasi yoki mos yozuvlar tekisligi sifatida ham tanilgan optik yassi shisha yoki metall yuzalarning tekisligini tekshirish uchun ishlatiladi. Wen bizning mos yozuvlar tekisligimiz sinovdan o'tayotgan shisha yoki metall yuza bilan aloqada bo'lsa, interferentsiya chekkalari hosil bo'ladi. Qirralarning naqshi sinov qismining tekislik darajasini ko'rsatadi.
Maxsus Scientific optik kvartiralar butun dunyo bo'ylab optik mashinalar do'konlari tomonidan tayyor qismlarini sinab ko'rish uchun ishlatiladi. Bizning kvartiralarimiz sifat nazorati bo'yicha inspeksiya guruhlari tomonidan tayyor qismlarning jilosini sinab ko'rish va sertifikatlash uchun ham qo'llaniladi.
Ushbu optik kvartiralar nozik nometall uchun substrat sifatida ham ishlatilishi mumkin. Bunday oyna qoplamalari odatda kumush, oltin yoki maxsus dielektrik yuqori reflektorli qoplamadir. Siz ushbu qoplamani depozitga qo'yishingiz mumkin, yoki biz buni qila olamiz – narx uchun biz bilan bog'laning. Yuqoridagi jadvallarda yozilgan va bir haftalik yetkazib beriladigan standart optik kvartiralarimiz asosan kontaktni tekshirish uchun mo'ljallangan va shuning uchun biroz qulay kosmetik sifatga ega (80-50 skretch-dig). Bu kontaktni tekshirish uchun juda mos bo'lsa-da, agar siz ushbu kvartiralarni oyna substrati sifatida ishlatmoqchi bo'lsangiz, sizga yaxshiroq sirt sifati kerak bo'lishi mumkin, biz buni albatta taqdim etamiz – bu haqda ma'lumot olish uchun biz bilan bevosita bog'laning.
Agar siz alyuminiydan uzatiladigan to'lqin jabhasining aniqligini lambda/4 yoki undan yuqori darajagacha davom ettirishingiz mumkin bo'lgan aniq oynalarni izlayotgan bo'lsangiz, biz buni odatiy asosda keltirishimiz kerak – Bunday taklif uchun biz bilan bog'laning. Bu optik yassilar nozik oynalar sifatida foydalanish uchun mo'ljallanmagan (ya'ni uzatishda dyuym uchun taxminan 1 x lambdadan yaxshiroq), chunki sirt(lar) yuqori aniqlikda sayqallangan bo'lsa ham, yuzalar orasidagi kvars materialining katta qismi eritiladi. Sinishi indeksining bir xilligini bo'shashgan nazoratga ega. Bu shuni anglatadiki, yuzadan aks ettirilgan yorug'lik to'lqin jabhasida juda kichik degradatsiyaga uchrasa ham, deraza orqali o'tadigan yorug'lik sezilarli darajada ko'proq to'lqin fronti degradatsiyasiga uchraydi, odatda dyuym uchun 3 yoki 4 x lambda. E'tibor bering, uzatilgan to'lqin jabhasidagi buzilish ko'zga ko'rinmaydi – bu ajoyib oynaga o'xshaydi – agar siz uni interferometrda o'lchasangiz, ko'rsatkichlar to'lqin jabhasi degradatsiyasini ko'rsatadi. Agar sizga yaxshi uzatiladigan to'lqin old aniqligiga ega bo'lgan aniq oyna kerak bo'lsa, biz bilan bog'laning va biz taklif qilamiz. Biz aniq oynalarni muntazam ravishda qilamiz, lekin optik kvartiralar kabi birja dasturida emas.

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An optical flat is a contact optical measurement device used in conjunction with a monochromatic light source to measure precision flat surfaces. Lapmaster optical flats are manufactured from high quality fused quartz.Fused quartz is used because it possesses an extremely low coefficient of thermal expansion and extremely high resistance to abrasion. Even with the hardness of fused quartz the optical flat must be handled and used very carefully to prevent damage and scratches. It is important to not slide or rotate the optical flat on any surface. Optical lens tissue and alcohol should be used to clean optical flats. Since the measurement resolution of an optical flat is a light band (.0000116” or .295 micron), components must be flatter than 15 or 20 light bands in order for the optical flat to be able to make the interference fringes visible. This is not normally a problem since most flatness requirements are to achieve single digit light bands. Proper inspection procedure dictates that the optical flat must be large enough to completely cover a surface that has a flatness specification.

Lapmaster offers a standard line of round optical flats from 1” to 12” diameter supplied with a protective case. Each size optical flat is available in three accuracy’s, 1/2, 1/5 and 1/10 of a light band. The standard optical flats are accurate on both faces, but single side accurate optical flats are available by request. The accuracy simply indicates the actual measured flatness across the diameter of the optical flat. In other words, the optical flat accuracy is in fact the measured inaccuracy. The more accurate optical flats require greater manufacturing time and are thus more expensive.

Non-standard sizes (16” diameter maximum), shapes (square or rectangular) and “donut” type (flat has a hole machined in its center) optical flats are available from Lapmaster.

Lapmaster provides a service for reconditioning used optical flats. The maximum capability is 16” diameter, but 12” diameter optical flats are the largest that can currently be certified. Lapmaster uses a 12” diameter “master optical flat” that has been certified for accuracy by NIST (National Institute for Standards and Testing. Large chips, fractures and deep surface damage cannot be repaired.

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Optik yassi - bu aniq tekis yuzalarni o'lchash uchun monoxromatik yorug'lik manbai bilan birgalikda ishlatiladigan kontaktli optik o'lchash moslamasi. Lapmaster optik yassilari yuqori sifatli eritilgan kvartsdan ishlab chiqariladi. Eritilgan kvarts juda past termal kengayish koeffitsientiga va aşınmaya juda yuqori qarshilikka ega bo'lgani uchun ishlatiladi. Eritilgan kvartsning qattiqligida ham, shikastlanish va chizishlarning oldini olish uchun optik tekis ishlov berish va juda ehtiyotkorlik bilan foydalanish kerak. Optik tekislikni har qanday sirtda siljitmaslik yoki aylantirmaslik muhimdir. Optik kvartiralarni tozalash uchun optik linza to'qimasi va spirtli ichimliklarni ishlatish kerak. Optik tekislikning o'lchov ruxsati yorug'lik diapazoni (.0000116" yoki .295 mikron) bo'lganligi sababli, optik tekislik interferentsiya chekkalarini ko'rinadigan qilib qo'yishi uchun komponentlar 15 yoki 20 yorug'lik diapazonidan tekisroq bo'lishi kerak. Bu odatda muammo emas, chunki tekislik talablarining aksariyati bir raqamli yorug'lik diapazoniga erishishdir. To'g'ri tekshirish tartibi, optik tekislik tekislik xususiyatiga ega bo'lgan sirtni to'liq qoplash uchun etarlicha katta bo'lishi kerakligini ko'rsatadi.Lapmaster himoya sumkasi bilan ta'minlangan diametri 1 "dan 12" gacha bo'lgan yumaloq optik kvartiralarning standart liniyasini taklif qiladi. Har bir o'lchamdagi optik kvartira uchta aniqlik, 1/2, 1/5 va 1/10 yorug'lik diapazonida mavjud. Standart optik yassilar ikkala yuzda ham aniq, ammo bitta tomonli aniq optik kvartiralar so'rov bo'yicha mavjud. Aniqlik oddiygina optik yassi diametri bo'ylab haqiqiy o'lchangan tekislikni ko'rsatadi. Boshqacha qilib aytganda, optik tekis aniqlik aslida o'lchangan noaniqlikdir. Aniqroq optik kvartiralar ko'proq ishlab chiqarish vaqtini talab qiladi va shuning uchun qimmatroqdir.

Lapmasterdan nostandart o'lchamlar (diametri maksimal 16 dyuym), shakllar (kvadrat yoki to'rtburchaklar) va "donut" tipidagi (kvartiraning markazida ishlov berilgan teshikka ega) optik kvartiralar mavjud.

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Prior to use, carefully clean the optical flat and surface requiring measurement. The surface being measured must be reflective to view interference fringes. A monochromatic light source must be used to accurately determine flatness with an optical flat. Place a sheet of lens tissue onto the surface requiring inspection. Physically place the optical flat onto the lens tissue covering the surface requiring measurement. While relieving some of the optical flat weight, gently pull the lens tissue out from between the two surfaces. Place a finger on the center of the optical flat and press down to remove some of the air trapped between the surfaces. The visual curvature of the interference fringes (light bands), relative to a parallel straight reference line, indicate the high and low deviation from the flat plane. If one band crosses the reference line, the surface is one light band “out-of-flat”. If two bands cross the reference line, the surface is two light bands out-of-flat. The user’s judgement of the degree of band curvature is a drawback with this method of measurement. The initial light band pattern indicates the total deviation from the lapped plane and nothing about the direction of deviation (convex or concave). Additional technique with the optical flat must be employed to determine if the surface deviates up (convex) or down (concave).

Optical Flat Reflection Stand
Optical Flat StandA reflection stand is a devise used to allow an inspector the ability to view interference fringe patterns of a measured surface that is placed on the top surface of the optical flat. This “upside down” procedure must be used when measuring a component that will be stressed and forced from its natural shape by the weight of the optical flat. Large diameter carbon graphite components with small cross section profiles are notorious for being extremely physically unstable. This is a prime example of an application that requires a reflection stand for accurate flatness measurement.
The reflection stand consists of a fabricated polypropylene plastic housing containing an angle adjustable glass-viewing mirror. The front and top surface of the case is made from clear acrylic plastic. The stand works by supporting an optical flat above a mirror that is angled towards the clear acrylic front viewing panel of the unit. The appropriate size monochromatic light unit is placed on a step integral in the reflection stand with the diffusing lens overhanging the clear acrylic top surface of the reflection stand. A component requiring measurement is placed on top of the optical flat with its polished surface in contact with the flat.
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Ishlatishdan oldin optik tekislikni va o'lchovni talab qiladigan sirtni ehtiyotkorlik bilan tozalang. Interferentsiya chekkalarini ko'rish uchun o'lchanayotgan sirt aks ettiruvchi bo'lishi kerak. Optik tekislik bilan tekislikni aniq aniqlash uchun monoxromatik yorug'lik manbasidan foydalanish kerak. Tekshirishni talab qiladigan sirtga linza to'qimasini qo'ying. Jismoniy ravishda optik tekislikni o'lchashni talab qiladigan sirtni qoplaydigan linza to'qimalariga joylashtiring. Optik tekis og'irlikning bir qismini engillashtirganda, linza to'qimasini ikki yuza orasidan muloyimlik bilan tortib oling. Barmoqni optik tekisning o'rtasiga qo'ying va yuzalar orasiga tushgan havoning bir qismini olib tashlash uchun pastga bosing. Parallel to'g'ri yo'naltiruvchi chiziqqa nisbatan interferentsiya chekkalarining vizual egriligi (yorug'lik chiziqlari) tekis tekislikdan yuqori va past og'ishlarni ko'rsatadi. Agar bitta tarmoqli mos yozuvlar chizig'ini kesib o'tsa, sirt bitta yorug'lik chizig'i «tekisdan tashqarida» bo'ladi. Agar ikkita chiziq mos yozuvlar chizig'ini kesib o'tsa, sirt tekislikdan tashqarida ikkita yorug'lik chizig'i bo'ladi. Foydalanuvchining tarmoqli egrilik darajasi haqidagi mulohazasi ushbu o'lchash usulining kamchiliklari hisoblanadi. Yorug'lik chizig'ining dastlabki namunasi lapped tekislikdan umumiy og'ish va og'ish yo'nalishi (qavariq yoki konkav) haqida hech narsa ko'rsatmaydi. Sirtning yuqoriga (qavariq) yoki pastga (konkav) og'ishini aniqlash uchun optik tekislik bilan qo'shimcha texnikadan foydalanish kerak.

Optik tekis aks ettiruvchi stend

Optik tekis stendA ko'zgu stendi – bu inspektorga optik tekisning yuqori yuzasiga joylashtirilgan o'lchangan sirtning shovqin chegaralarini ko'rish imkoniyatini beradigan qurilma. Ushbu «teskari» protsedura optik tekisning og'irligi bilan tabiiy shaklidan zo'riqish va majburlanadigan komponentni o'lchashda qo'llanilishi kerak. Kichik kesma profilli katta diametrli uglerod grafit komponentlari juda jismonan beqarorligi bilan mashhur. Bu tekislikni aniq o'lchash uchun aks ettirish stendini talab qiladigan dasturning eng yaxshi namunasidir.

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Optical Flat – Single & Double Sided

Optical flats are used to check the flatness of a substrate. When a high quality optical flat is placed on top of a polished substrate and used with a monochromatic light source, light bands are formed. The number of rings or straight lines shown is an indication of how flat the part is.
Produced from Quartz, Kemet Optical Flats are available in single and double sided, ¼ light band accuracy (Higher accuracy available on request), in sizes from 25mm up to 600mm diameter. Larger sizes made to order with configurations such as square optical flats, rectangle optical flats, donut optical flats and custom optical flat thickness are available. They are supplied with Certificate of Conformity with full traceability to international standards. Special optical flats are available on request.
Over a period of time an optical flat can get scratched and/or chipped so it cannot be used or recalibrated without refurbishing. For small optical flats (less than 4”/100mm), depending on the level of damage, it may be more cost effective to purchase a new one but for larger flats Kemet offers a reconditioning/refurbishing/calibration service to lambda/20, with the use of interferometers and continuous pitch polishers. As with the calibration service interferograms and inspection certificates are provided for reworked optical flats.
The following shows some examples of optical flats that have been returned to Kemet for calibration (lightly scratched), re-polishing and calibration (more heavily scratched) and complete refurbishing (heavily scratched and/or chipped – chips are ground out and polished). Contact Kemet for a quotation.
The width of the light bands is dependant upon the thickness of the air wedge which always exists between two parts. Minute particles of dust or dirt on either surface will hold the flat far enough away from the part so that the light bands will be very narrow and close together. The thickness of the air wedge can be decreased either by more cleaning or by gently pressing on the optical flat to force out some of the air. As the air wedge thickness decreases the light bands become wider. The width of the light bands or the number of bands does not affect the surface measurement, only the ease of making an accurate reading. The bands need only to be as wide as necessary for an accurate interpretation of their curvature.

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Optik tekis – bir va ikki tomonlama

Optik tekisliklar taglikning tekisligini tekshirish uchun ishlatiladi. Yuqori sifatli optik yassi silliqlangan substrat ustiga qo'yilganda va monoxromatik yorug'lik manbai bilan foydalanilganda, yorug'lik bantlari hosil bo'ladi. Ko'rsatilgan halqalar yoki to'g'ri chiziqlar soni qismning qanchalik tekis ekanligini ko'rsatadi.
Kvarsdan ishlab chiqarilgan Kemet Optik Flats bir va ikki tomonlama, ¼ yorug'lik diapazonining aniqligi (so'rov bo'yicha yuqori aniqlik), diametri 25 mm dan 600 mm gacha bo'lgan o'lchamlarda mavjud. Kvadrat optik yassilar, to'rtburchaklar optik yassilar, donutli optik tekislar va maxsus optik tekis qalinligi kabi konfiguratsiyalar bilan buyurtma berish uchun tayyorlangan kattaroq o'lchamlar mavjud. Ular xalqaro standartlarga to'liq kuzatilishi mumkin bo'lgan Muvofiqlik sertifikati bilan ta'minlangan. Maxsus optik kvartiralar so'rov bo'yicha mavjud.
Vaqt o'tishi bilan optik kvartira tirnalgan va/yoki yorilib ketishi mumkin, shuning uchun uni ta'mirlamasdan ishlatish yoki qayta kalibrlash mumkin emas. Kichkina optik kvartiralar uchun (4»/100 mm dan kam), shikastlanish darajasiga qarab, yangisini sotib olish tejamkor bo'lishi mumkin, ammo kattaroq kvartiralar uchun Kemet lambda/20 ga qayta tiklash/ta'mirlash/kalibrlash xizmatini taklif qiladi. Interferometrlardan va doimiy pog'onali jilolardan foydalanish. Kalibrlash xizmatida bo'lgani kabi, qayta ishlangan optik kvartiralar uchun interferogrammalar va tekshirish sertifikatlari taqdim etiladi.
Quyida kalibrlash (engil tirnalgan), qayta sayqallash va kalibrlash (ko'proq tirnalgan) va to'liq ta'mirlash (qattiq tirnalgan va/yoki chiplar maydalangan va jilolangan) uchun Kemetga qaytarilgan optik kvartiralarning ba'zi misollari keltirilgan. Kotirovka uchun Kemet bilan bog'laning.
Yorug'lik chiziqlarining kengligi har doim ikki qism o'rtasida mavjud bo'lgan havo xanjarining qalinligiga bog'liq. Ikkala yuzadagi chang yoki axloqsizlikning kichik zarralari tekislikni qismdan etarlicha uzoqda ushlab turadi, shunda yorug'lik chiziqlari juda tor va bir-biriga yaqin bo'ladi. Havo xanjarining qalinligini ko'proq tozalash yoki havoning bir qismini chiqarish uchun optik yassi ustiga sekin bosib kamaytirish mumkin. Havo xanjarining qalinligi kamayishi bilan yorug'lik chiziqlari kengayadi. Yorug'lik chiziqlarining kengligi yoki chiziqlar soni sirt o'lchamiga ta'sir qilmaydi, faqat aniq o'qishni osonlashtiradi. Bantlar ularning egriligini aniq talqin qilish uchun kerakli darajada keng bo'lishi kerak.

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Measuring flatness using an optical flat entails direct contact between the specimen to be measured and the optical flat itself. Holding the surface of a high precision optical flat against the test specimen under monochromatic light creates visible light bands, which are formed by the air gaps where the two surfaces are not in perfect contact. These interference fringes show the contour of the surface under test. The light and dark patterns visually represent the flatness of the surface being tested, and it is the curve and spacing between these fringes which indicate the surface accuracy.

Disadvantages of Surface Flatness Measurements with Optical Flats:
The optical flat is in intimate contact with the test sample, causing scratches in both.
Test samples are placed on top of an optical flat for viewing with the help of a mirror. When placed horizontally, large diameter, thin parts can conform to the surface of the optical flat, causing an inaccurate reading.
Classic Fizeau interferometers cannot measure flatness of thin, transparent glass 0.5mm (.020») and thinner in a free-state, without applying an opaque coating to the opposite side of the thin part to be measured. This also distorts the specimen, and will cause an inaccurate reading.
Flatness Measuring Instrument from Valley Design
Patented, our new non-contact interferometer, the Indars Interferometer, is designed to alleviate the problems inherent with using optical flats or Fizeau interferometers as discussed above. The Indars Interferometer has been specifically optimized for the flatness characterization of thin, transparent wafers, substrates and windows. Its unique design allows wafers to be positioned vertically, eliminating most bending forces applied by gravity and without necessitating the application of flatness distorting films.

For additional information on Optical flat interferometer see:

• 
  Indars Optical Interferometer
  

• 
  Fizeau Interferometer
  

• 
  Transparent wafer flatness measurements
  

• 
  Flatness interferometer and how it works
  

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Optik yassi yordamida tekislikni o'lchash o'lchanadigan namuna va optik tekisning o'zi o'rtasida to'g'ridan-to'g'ri aloqa qilishni talab qiladi. Yuqori aniqlikdagi optik tekisning sirtini monoxromatik yorug'lik ostida sinov namunasiga nisbatan ushlab turish, ikkita sirt mukammal aloqada bo'lmagan havo bo'shliqlari tomonidan hosil bo'ladigan ko'rinadigan yorug'lik chiziqlarini hosil qiladi. Ushbu interferentsiya chekkalari tekshirilayotgan sirtning konturini ko'rsatadi. Yorug'lik va qorong'i naqshlar sinovdan o'tayotgan sirtning tekisligini vizual tarzda ifodalaydi va bu qirralarning orasidagi egri chiziq va masofa sirt aniqligini ko'rsatadi.

Optik tekisliklar yordamida sirt tekisligini o'lchashning kamchiliklari:

Optik yassi sinov namunasi bilan yaqin aloqada bo'lib, ikkalasida ham chizishlarga olib keladi.
Sinov namunalari oyna yordamida ko'rish uchun optik yassi ustiga qo'yiladi. Gorizontal joylashtirilganda, katta diametrli, nozik qismlar optik tekisning yuzasiga mos kelishi mumkin, bu noto'g'ri o'qishga olib keladi.
Klassik Fizeau interferometrlari o'lchanadigan yupqa qismning qarama-qarshi tomoniga shaffof bo'lmagan qoplama qo'llamasdan, 0,5 mm (.020») yupqa shaffof shishaning tekisligini va erkin holatda yupqaroqligini o'lchay olmaydi. Bu ham namunani buzadi va noto'g'ri o'qishga olib keladi.
Vodiy dizaynidan tekislikni o'lchash asbobi
Patentlangan yangi kontaktsiz interferometrimiz Indars Interferometer yuqorida muhokama qilinganidek, optik yassi yoki Fizeau interferometrlaridan foydalanish bilan bog'liq muammolarni engillashtirish uchun mo'ljallangan. Indars Interferometer nozik, shaffof gofret, taglik va derazalarning tekisligini tavsiflash uchun maxsus optimallashtirilgan. Uning noyob dizayni gofretlarni vertikal ravishda joylashtirish imkonini beradi, bu esa tortishish ta'sirida qo'llaniladigan ko'pchilik egilish kuchlarini yo'q qiladi va tekislikni buzuvchi plyonkalarni qo'llashni talab qilmaydi.

Optik yassi interferometr haqida qo'shimcha ma'lumot olish uchun qarang:

• Indars optik interferometri
• Fizeau interferometri
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Optical Flat – Single & Double Sided

Optical flats are used to check the flatness of a substrate. When a high quality optical flat is placed on top of a polished substrate and used with a monochromatic light source, light bands are formed. The number of rings or straight lines shown is an indication of how flat the part is.
Produced from Quartz, Kemet Optical Flats are available in single and double sided, ¼ light band accuracy (Higher accuracy available on request), in sizes from 25mm up to 600mm diameter. Larger sizes made to order with configurations such as square optical flats, rectangle optical flats, donut optical flats and custom optical flat thickness are available. They are supplied with Certificate of Conformity with full traceability to international standards. Special optical flats are available on request.
Optical Flat showing light bands on substrate.
It is important to regularly calibrate optical flats and Kemet offers a calibration service to lambda/20 using 4» and 12» interferometers to measure the flatness of the optical flat and provide interferograms and inspection certificates.
Optical Flat Cleaning/Care Kit
It is also important to maintain optical flats using Kemet’s Optical Flat Cleaning/Care Kit, as taking special care of them will ensure accuracy and long service.
Over a period of time an optical flat can get scratched and/or chipped so it cannot be used or recalibrated without refurbishing. For small optical flats (less than 4”/100mm), depending on the level of damage, it may be more cost effective to purchase a new one but for larger flats Kemet offers a reconditioning/refurbishing/calibration service to lambda/20, with the use of interferometers and continuous pitch polishers. As with the calibration service interferograms and inspection certificates are provided for reworked optical flats.

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Optik tekis – bir va ikki tomonlama

Optik tekisliklar taglikning tekisligini tekshirish uchun ishlatiladi. Yuqori sifatli optik yassi silliqlangan substrat ustiga qo'yilganda va monoxromatik yorug'lik manbai bilan foydalanilganda, yorug'lik bantlari hosil bo'ladi. Ko'rsatilgan halqalar yoki to'g'ri chiziqlar soni qismning qanchalik tekis ekanligini ko'rsatadi.
Kvarsdan ishlab chiqarilgan Kemet Optik Flats bir va ikki tomonlama, ¼ yorug'lik diapazonining aniqligi (so'rov bo'yicha yuqori aniqlik), diametri 25 mm dan 600 mm gacha bo'lgan o'lchamlarda mavjud. Kvadrat optik yassilar, to'rtburchaklar optik yassilar, donutli optik tekislar va maxsus optik tekis qalinligi kabi konfiguratsiyalar bilan buyurtma berish uchun tayyorlangan kattaroq o'lchamlar mavjud. Ular xalqaro standartlarga to'liq kuzatilishi mumkin bo'lgan Muvofiqlik sertifikati bilan ta'minlangan. Maxsus optik kvartiralar so'rov bo'yicha mavjud.
Substratdagi yorug'lik chiziqlarini ko'rsatadigan optik tekis.
Optik tekisliklarni muntazam ravishda kalibrlash muhim va Kemet optik yassi tekisligini o'lchash va interferogrammalar va tekshirish sertifikatlarini taqdim etish uchun 4» va 12» interferometrlar yordamida lambda/20 ga kalibrlash xizmatini taklif qiladi.
Optik tekis tozalash / parvarishlash to'plami
Shuningdek, Kemetning Optik Yassi Tozalash/G'amxo'rlik to'plamidan foydalangan holda optik kvartiralarni saqlash muhimdir, chunki ularga alohida g'amxo'rlik qilish aniqlik va uzoq xizmatni ta'minlaydi.
Vaqt o'tishi bilan optik kvartira tirnalgan va/yoki yorilib ketishi mumkin, shuning uchun uni ta'mirlamasdan ishlatish yoki qayta kalibrlash mumkin emas. Kichkina optik kvartiralar uchun (4»/100 mm dan kam), shikastlanish darajasiga qarab, yangisini sotib olish tejamkor bo'lishi mumkin, ammo kattaroq kvartiralar uchun Kemet lambda/20 ga qayta tiklash/ta'mirlash/kalibrlash xizmatini taklif qiladi. Interferometrlardan va doimiy pog'onali jilolardan foydalanish. Kalibrlash xizmatida bo'lgani kabi, qayta ishlangan optik kvartalar uchin interferugrama tagdim etadi.


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