标题: 求助，帮师妹答几个光学题目，谢谢了 [打印本页] 作者: wangnachina 时间: 2007-9-13 13:37 标题: 求助，帮师妹答几个光学题目，谢谢了 2) Imagine you need to measure an optical properties of a
surface: angular distribution of scattered radiation (for each
wavelength).
How you would do this, using which device. What difficulties and
which accuracy do you expect.
3) Imagine you faced a situation when customer's PLED
(Plane Light Emitter )
was simulated, but the results (spatial distribution of brightness
over screen) differs substantially from what was measured (by
customer). The PLED consists of a CCFL tube, an LGP with micro
dimples on its bottom, wrapped in a white plastic reflector
sheet, and a couple of DBEFs (this plates with microprisms) laid
on its emitting surface. Even with DBEFs removed there remains a
viable difference.
Specifications of geometry and CCFL were given by customer,
optical properties of reflector sheet and DBEFs were measured.
What would you do. Where you suspect the error. Which its
magnitude do you consider normal (e.g. caused by inaccuracy of
measurement, deviation of CCFL instances etc).
4) Imagine you need to measure which (scattering) particles are
dispersed in a solution (e.g. paint). Expected size of particles
is say
case A 10-500 nm,
case B 5-50 um
and concentration (volumetric) can be varied between say 0.5% to
say 10%. How would you proceed. Which difficulties do you expect
and which accuracy hope to achieve.
How you can measure their spatial distribution if it is
inhomegeneous.
5) Imagine you faced a fluorescent sample (solution or surface).
How would you measure it? Which characteristics are pertinent to
fluorescence? How they are defined? How to simulate fluorescence
using it?
6) Imagine a customer device (pls give SSML scene). They say
there is emitter that is < 1/100 (!!) wavelength in size. What
can such emitter be. How you can simulate it.
7) Do you have experience with CCD measuring cameras and photo
diode sensors. How you estimate their strong and weak points and
accuracy. What is their dynamic range. How to measure sample
whose reflectance has WIDER range of brightness.
8) Imagine you need to simulate scattering by particles dispersed
in a clear plastic. They have cylindrical shape and are of size,
say
case A < 0.1 um
case B 1 to 5 um
case C some 20-30 um
How would you proceed. Which data you need and which difficulties
and errors do you expect.
9) What are different cases when diffraction occurs in optics?
What are their differences? How to simulate them.
Which method of solution of diffraction problems in optics (under
monochrome illumination) do you know. Which of them you operated.
What are their weak and strong points.
10) Imagine we have solution of a diffraction problem for a
snowflake under monochrome illumination, that is so-called phase
function.
How it can be (resp. can not be) used for simulation of
scattering of sun light in a snow storm, e.g. to see bloom around
sun disk. What inaccuracies do you expect. How to do.
11) What is light coherence. How to measure it. How it affects
scattering and when. Pls list coherence characteristics of some
common light sources.
12) Imagine you have a PLED (see pt 3). Dimples on LGP surface
have spatially varied density, orientation, size and maybe shape.
These parameters, or rather their space distribution, must be
chosen (designed) so as to achieve e.g. maximally uniform
brightness of emitted light. Experience shows that e..g. size may
vary about order of magnitude from one edge to another, and with
a proper profile one may achieve nearly (+/- a few percent or
less) brightness.
The work consists of two coupled phases: ANALYSIS (calculation of
characteristics of emission for GIVEN distributions) and
OPTIMISATION STEP (changing those distributions by comparing
obtained and target emissions).
How you would do such a design. What simulation and optimisation
method would you use. Which difficulties do you expect.
What are your estimates of required run time and memory.
13) Design of paint color. Imagine you have a palette of
available pigments, say 100 of them. You need to fabricate a
paint with desired optical properties (notice that its color may
depend on angle of observation/illumination).
Design consists in choosing which pigments among available to
use, and in which proportions (concentrations).
How would you proceed. Which data on pigments and target paint
would you use. How the optimisation procedure can be organized.
As a result (this or that way) you got formulation of the paint.
Now suppose it is fabricated, applied, dried and measured. What
deviation from predicted results do you expect. Why.
14) Imagine you have a rough surface (brushed metal). Which
measuring method do you suggest to measure its profile.
Imagine this was done, and the sample was simulated, The results
however deviate from direct measurement of scattering. What the
is the reason as you suspect.
15) Imagine that in a measurement you need to attenuate
illumination (change its amplitude better gradually but at least
granularly), Which attenuator will you use. What is its string
and weak points and expected accuracy.作者: shaka2007 时间: 2007-9-14 17:03
刚刚看到你的消息了，但是很抱歉，这些问题不是我的专长，没有办法回答你，如果是激光相关的还可以，应用光学这块我也在学习，看看其他人的回答吧