(光電信息工程專業(yè)英語)專業(yè)英語第七講Geometrical-Optics課件

1、光電信息工程專業(yè)英語Chapter 2 Geometrical Optics光電信息工程專業(yè)英語Chapter 2 Geometrica1.6 Locating Images by Ray Tracing8 . An ordinary piece of flat glass, such as a window with parallel faces, passes light without changing its direction. Although the direction of the ray does not changes, the ray is displaced later

2、ally. 翻譯： 一個普通的平面玻璃，例如帶有兩個平行面的玻璃窗，透過光線而不改變它的方向。雖然方向不改變，但光線會發(fā)生側移。1.6 Locating Images by Ray Tra1.6 Locating Images by Ray TracingThe object may be self-luminous, giving off its own light(like the sun or a light bulb), or it may reflect the light that falls on it (like an apple or a page of this book)

3、.9. In either case, an image of the object is formed where light rays that come from points on the object intersect or at the points from which the rays appear to originate.翻譯：任何一種情況下，在來自物的光線相交的位置形成圖像（實），或在看起來發(fā)出光線的點形成圖像（虛）。1.6 Locating Images by Ray Tra(光電信息工程專業(yè)英語)專業(yè)英語第七講Geometrical-Optics課件(光電信息工程專

4、業(yè)英語)專業(yè)英語第七講Geometrical-Optics課件1.7 The Thin-lens Equation1. In the predceding derivation, we examined the special case of a converging lens with the object placed outside the focal point. However, the thin-lens equation holds for both converging and diverging thin lenses and for any object distance,

5、 provided the following sign conventions are maintained.詞匯：Preceding在前的，前述的Hold 有效Sign convention 符號規(guī)則Maintain 維持，供養(yǎng)，繼續(xù)，主張參考翻譯：在上述的推導中，我們檢驗了物在會聚透鏡焦點以外的特殊情況。然而，如果遵守下述的符號規(guī)則，薄透鏡公式對于會聚和發(fā)散薄透鏡都是有效的，且不論物體遠近。Provided,conj.假如，倘若：Provided (that) there is no opposition, she will be our new chairman. vt.提供；給予（p

6、rovide的過去式） A lens whose thickness is small in comparison with its focal length is called a thin lens.1.7 The Thin-lens Equation1. I1.8 Spherical Mirrors2. A concave mirror reflects light from the inner surface of a sphere; a convex mirror reflects light from the outer surface.1.8 Spherical Mirrors2

7、. A conc3. However, if the diameter of the incident beam is a large fraction of the diameter of the mirror, the reflected rays do not all converge to the same point, and the image is somewhat blurred. This effect, called spherical aberration, is discussed in more detail in section 1.9.1.8 Spherical

8、Mirrors3. However, if the diameter of1.9 Lens Aberrations4. Up to now, our discussion of lenses has not taken into account some of the optical imperfections that are inherent in single lenses made of uniform material with spherical surfaces. These failures of a lens to give a perfect image are known

9、 as aberrations. 句子結構：our discussion has not taken into account imperfections其它句子成分：optical imperfections that are inherent in single lensessingle lenses made of uniform material with spherical surfaces翻譯：迄今為止，我們對透鏡的討論還沒有考慮由均質材料組成的具有球面的單透鏡固有的光學缺陷。這些透鏡缺陷就是像差.1.9 Lens Aberrations4. Up to nAberrations像

10、差：使像模糊：球差：Sperical aberration慧差：coma aberration像散： astigmatism 使像變形：場曲：field curvature畸變：distortion色差：chromatic aberration參考：1./article-1584.html2./wiki/%E8%B1%A1%E5%B7%AEAberrations像差：5. We see that what we said earlier about thin lenses is strictly true only in the so-called paraxial approximation

11、-that is, only for incoming rays that are not far from axis and that are parallel to the axis. These limitations explain why the center of an image is often relatively clear while the edges are considerably more distorted.句子結構：We see that句子其它成分：what we said is trueparaxial approximation-that is, onl

12、y for incoming rays that are not far from axis and that are parallel to the axis.參考翻譯：我們發(fā)現，只有在所謂的傍軸近似條件下，我們先前關于薄透鏡（的公式）才是嚴格正確的也就是說，只有當入射光線離光軸較近，且平行于光軸時才成立。這些限制解釋了為什么圖像常常中央相對清晰而邊緣會有較大的變形。1.9 Lens Aberrations5. We see that what we said ea6.However, to reduce aberrations of this kind to an acceptable l

13、evel for optical instruments such as microscopes, binoculars, or cameras, each lens must be made of several thin lenses in combination. 參考翻譯1：然而，為了減小這種由于光學儀器所帶來的在允許之內的像差，例如顯微鏡，雙筒望遠鏡，或者照相機，每一個鏡頭必須由幾個混合的薄透鏡組成。參考翻譯2：然而，為了使光學光學儀器（例如顯微鏡，雙筒望遠鏡，或者照相機）的像差減少至可接受的程度，每一個鏡頭必須由幾個薄透鏡組合構成。幾個要點：reduceto an acceptab

14、le levelseveral thin lenses in combination1.9 Lens Aberrations6.However, to reduce aberratio7.Along with the aberrations mentioned above, there is an additional complication: the index of refraction varies slightly for light of different colors that is, different wavelengths. This variation is most

15、easily seen in the action of a prism. along with和一起，同一道參考翻譯：與上面提到的像差一起的，另外還有一個復雜情況：（同一種材料）折射率對不同顏色的光有微小的差別，也就是說對不同波長，折射率是不同的。這種差異在棱鏡中最容易看到。1.9 Lens Aberrations7.Along with the aberrations m8. Chromatic aberration can be troublesome in any optical instrument that uses lenses. To overcome this problem

16、 in telescopes, Isaac Newton invented the reflecting telescope, which uses a focusing mirror instead of an objective lens. No dispersion occurs when light is reflected from the mirror, so chromatic aberration is eliminated from that element.牛頓1672年使用的6英寸反射式望遠鏡復制品，為皇家學會所擁有。 1994年，不列顛哥倫比亞大學開始建造一臺口徑為6米

17、的旋轉水銀面望遠鏡大型天頂望遠鏡（LZT），并于2003年建成1.9 Lens Aberrations8. Chromatic aberration can be9. By choosing materials with indices of refraction that depend in different ways on the color of the light, lens designers can ensure that positive and negative lens elements compensate for each other by having equal b

18、ut opposite chromatic effects.參考翻譯1：對不同折射率材料的選擇依靠光線在不同方式中的顏色，透鏡設計者可以通過使正負透鏡相等但有相反的色效益來確保正負透鏡相補償。參考翻譯2：不同顏色的光會被沿不同路徑折射，通過選擇不同折射率的材料，透鏡設計者可以確保正透鏡和負透鏡單元具有相反的色差效應，從而（使色差）相互補償。1.9 Lens Aberrations9. By choosing materials with aberrationThe blurring in the first photograph is primarily the result of spheraical aberration, and the inaccuracy in the color is due to chromatic aberration. A color photograph thaken through the well-corrected lens (second figure) shows no visible color errors.aberrationThe blurring in the Aspherics lensAspherics lens名詞復數medium media