بعض تطبيقات الليزر المشاريع المعماريّة الاتصالات الكهروضوئية صناعة الحديد و الصلب الأغراض البيئيّة الاستعمالات الطبيّة المجالات الأمنيّة والحربيّة المطيافية الذرية

تطبيقات الليزر في المشاريع المعماريّة Laser pointer and laser level Straight line marking, or plan of reference. Many daily applications require a precise reference line for alignment. Examples are: Laying pipes of gas, water, electricity, etc. Digging tunnels under-ground (such as the one under the English Channel between England and France). Alignment of mechanical systems. Marking spots for pointing invisible radiation from another laser (such as Nd-YAG or CO2 lasers). The visible laser radiation is aligned parallel to the invisible radiation, such that it mark the place where the invisible beam is pointing. Marking a reference plane for construction: By using a vibrating (or rotating) mirror to reflect a visible laser light, a perfect plane is defined in space. The mirror is vibrating around one axis, so the light is reflected into consecutive angles continuously, thus defining a perfect plane. Since the vibration of the mirror is at a frequency greater than the persistence of vision in the brain, the viewer see a plane of light. This plane helps aligning walls, sealing, etc. in industrial construction. عند حفر الأنفاق أو رفع المباني أو انشاء الطرق يمكن خط الخطوط المستقيمة و لمسافات بعيدة باستخدام الليزر.

تطبيقات الليزر في صناعة الحديد و الصلب The mechanism of interaction between the laser beam and the processed material: Thermal Effects - Most of the applications of lasers in material processing were based on the absorption of the laser radiation inside the material, and the effects were thermal in nature. The absorption process transfers energy to the material. As a result, there is a rise in the temperature in that region to high temperatures. Photochemical Effects - Breaking the bonds between the molecules in the material. The Excimer laser (see chapter 6.1.7) emits in the Ultra-Violet (UV) part of the electromagnetic spectrum, and its photons are very energetic. It can be used to cut very delicate and accurate structures without causing thermal damage to surrounding areas. الحفر و القطع بالليزر اللحام بالليزر click here

ميّزات استخدام الليزر في الأغراض الطبيّة: تطبيقات الليزر في الطب ميّزات استخدام الليزر في الأغراض الطبيّة: 1- قلة النزيف 2- قلة الشعور بالألم بعد العمليّة 3- عدم الحاجة إلى التعقيم 4- وضوح الرؤية عند أداء العمليّة 5- امكانيّة معالجة أنسجة دون أخرى (باختيار طول موجي معيّن) 6- سهولة العمل تحت المجهر 7- اجراء عمليات من غير فتح جراحي (باستخدام الألياف البصريّة) 8- دقة القطع باستخدام الليزر 9- امكانيّة التحكم في العمليّة عن طريق الحاسب الآلي

هناك أربعة أنواع رئيسيّة من الليزر تستخدم في الأغراض الطبيّة: هناك أربعة أنواع رئيسيّة من الليزر تستخدم في الأغراض الطبيّة: 1- ليزر ثاني أكسيد الكربون (CO2 laser) 2- ليزر النيودميوم ياق (Nd-YAG laser) 3- ليزر أيون الأرجون (Ar ion laser) 4- الليزر الصبغي (dye laser) و لكل من هذه الأنواع ميّزاته (و سلبيّاته!)

الليزر و العين: 1- تلحيم الشبكيّة 2- تعديل العدسة Lasers for eye treatment The laser was invented in 1960, and in 1961 this laser (Ruby) was used by eye doctors. It is natural that the eye was chosen to be the first organ for performing medical experiments, since the eye is transparent to the electromagnetic spectrum in the visible range. Another natural device that helps was the lens in the eye, which focuses the electromagnetic radiation onto the retina. Thus, increasing the power density by orders of magnitude. Using Excimer laser under computer control, a change in the shape of the cornea can be precisely made, by removing sub micron layers from the cornea. The operation is called PRK = Photo-Refractive Keratotomy and most of the problems with focusing the image on the retina can be repaired. 1- تلحيم الشبكيّة 2- تعديل العدسة

الليزر و الأمراض الجلديّة

الليزر و النزيف المعوي الليزر و التهاب الرحم الليزر و المسالك البوليّة الليزر و علاج السرطان الليزر و جراحة الأذن

تطبيقات الليزر في مجال الاتصالات و في تخزين المعلومات و قراءتها الليزر في مجال الاتصالات (optical communication) : إما عن طريق الألياف البصريّة أو في الهواء الطلق!

ميّزات الأقراص المدمجة: الليزر و تخزين المعلومات في الأقراص المدمجة (CD&DVD): ميّزات الأقراص المدمجة: 1- كثافة المعلومات عالية! 2- سرعة تحصيل المعلومة 3- ليس هناك مماسّة ميكانيكيّة، و بالتالي لا ينهك القرص 4- لا يلزم الاحتياط عند التخزين، فهو لا يتأثر بالمجالات المغناطيسيّة و لا بالرطوبة (أو الماء)

تركيبة الأقراص المدمجة

تركيبة قارئ القرص المدمج نقاش لماذا بالليزر؟ Some numerical data on the structure of CD: The total length of the track is about 5 kilometers (!). The total number of pits is about 2*109 (more than 2 Billion !). The width of each pit is 0.6 [mm]. The length of each pit is 0.83-3.05 [mm], in 9 discrete steps. The depth of each pit is: 0.11 [mm]. The distance between adjacent tracks is 1.6 [mm]. The density of tracks is about 16,000 TPI (Tracks Per Inch), For comparison: human hair covers about 60 tracks. The wavelength of the Diode laser reading the CD is 780 [nm]. The spot size of the beam on the reflecting surface of the CD is about 1 [mm].

قراءة المعلومات بالليزر (laser bar code scanners): نقاش لماذا بالليزر؟ Bar code is used for identifying specific items in many applications such as: Inventory items in a storage, market, etc. Identifying workers in registering time present (although magnetic cards are much more efficient). Quality control in assembly lines. Reading a bar code optically is much faster than using a keyboard and pressing a large number of times for all the numbers of the identification code. The number of mistaken identity using optical methods is much lower than other identification methods. Bar code system is very simple to operate even by a non-professional employee. It is used to collect data accurately and reliably for data management systems. Any way in which there is a relative movement between the bar code label and the laser beam can be used. An example: Moving a "light pen" on the bar code. Moving the product across a beam coming from a fixed laser inside the table. Using a moving light beam from a stable system (automatic scanning system).

قراءة المعلومات بالليزر: النظام الثنائي البسيط النظام العالمي للمنتوجات (UPC) Methods for reading bar codes The optical system used to read the information from the bar code does not depend on the coding method. Reading the information is done in certain stages: The laser beam scan the code and is reflected from it to a detector or collection of detectors (photodiods). The detectors transform the optical signals into electrical signals. The electrical signals are transferred into the computer and translated by it to numbers and digits which describe the product. This information is used by the computer for further processing (printing a receipt, managing inventory, etc.). Increasing reliability and avoiding mistakes from reflection of standard illuminations: The fact the laser has the monochromatic light (a single defined wavelength), enable a filter in front of the detector to transmit to the detector only the laser wavelength. This way reflections of other light sources from the bar code are not detected by the detector. Thus, only the information from the bar code illuminated by the laser reaches the detector. النظام 2 من 5

قراءة المعلومات بالليزر: Advantages of the Automatic Scanning System: High level of safety - the beam trojectory is determined in advance toward the bar code and there is no danger of pointing the laser beam into unwanted directions. Very high scanning rate (tenth of meter per second) such that the beam scan the code many times and the computer can check and verify, thus increasing the reliability of reading. Compared to the "light pen" where the scanning rate is determined by the manual movement of the operator’s hand and limited to one scan per second. The scanning rate is fixed and is not influenced by the shaking of the operator’s hand. Using fixed scanning rate, it is very easy to calculate the widths of the dark and bright bands, thus decreasing the number of mistakes in reading the bar code. The entire system is hidden and protected, and there is no damage to external parts such as the "light pen", which is connected by a cable to the computer. Automatic scanning system can operate without an operator, in systems where the products are moving (such as in assembly line). رسم يبيّن الأدوات المستخدمة في قارئ المعلومات

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