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This kind in the lens front sunglasses online surface produces

This kind in the lens front sunglasses online surface produces the reflection can only cause others to look when Dai Jingzhe eye, saw is actually lens surface gonorrhea light. When photograph, this kind of reflection serious will influence also wear Mirror's artistic. " Ghost " The eyeglasses optics theory thought that the spectacle lenses refraction strength will cause to regard the object the distant point to form a clear elephant in Dai Jingzhe, may also explain that for will regard the optical fiber through the lens has the deflection and gathers on the retina, will form the image point. But Because the refraction lens' around surface's curvature is different, and has the ration the reflected light, between them will produce the internal reflection light. The internal reflection can only nearby the distant point spherical surface have sunglasses australia the virtual image, is also produces the virtual image spot nearby retina's image point. These virtual image spot Will affect will regard the clarity and comfortableness. Dazzles all optical system to be likely same, the eye is not perfect, becomes the elephant on the retina is not a spot, but is a blur circle. Therefore, two consecutive point's feelings are by two compound more or less overlap molds Sticks the circle to produce. So long as between two spot distances are big enough, will have two spot feelings on retina's image formation, but if two spots will be too close, then two blur circles will tend to and superpose, is taken for is a spot. The contrast gradient may use for to reflect this kind Phenomenon, expression vision clarity. The correlative value must be bigger than some determination value (to realize threshold, is equal in 1-2) only then can guarantee that the eye distinguishes two neighbor spots. The contrast gradient formula is: D= (a-b)/(a+b) C is a contrast gradient, two neighboring On the retina the image formation feeling maximum is a, the neighboring part's minimum value is b. If the contrast gradient C value is higher, the explanation vision system is higher to these two spot resolution, the feeling is clearer; If two object points are close, their neighboring sunglasses online
australia part The minimum value is quite close to the maximum, then the C value is low, explained that the vision system feels to these two spots not clearly, or cannot distinguish clearly. Let us simulate this kind of scene to produce: Night, wears eyeglasses' driver to see the opposite distant place to have two clearly from The driving is coming to his Che Qi. This time, tags along after that automobile's headlight after driver lens on the surface has the reflection: This reflected light the elephant which formed on the retina increased two by the viewpoint intensity (bicycle headlight). Therefore, a section and b section The length increases, is that as it may the denominator (a+b) to increase, but the member (a-b) maintains invariable, therefore has caused the C value reduction. Contrast compression's result will make the existence two riding a bicycle person's feeling which the pilot will produce at first to superpose into the sole elephant, will be just like differentiates them The angle is reduced suddenly! Occupies incident light by the quantity reflected light the percentage to be decided by the lens material refractive index, may through the reflection quantity formula: R= (n-1) square/(n+1) square R: Lens' one-sided counter-reflection quantity's formula carries on the computation. Shoots measures n: Mirror sheet material The material refractive index for discount sunglasses example common resin material's refractive index is 50, reflected light R= (50 lens have two surfaces, if R1 is the lens front surface - the square/(50+ squares =0.04=4%. The quantity, after R2 is lens, superficial reflection quantity, then lens always instead Shoots measures R=R1+R2. when (calculates R2 the reflection quantity, the incident light is 100%-R.