CN105547650A - Method for determining transmittance of optical elements under condition of non-normal incidence - Google Patents

Abstract

The invention provides a method for determining the transmittance of optical elements under the condition of non-normal incidence, and belongs to the field of optical elements. The method is provided to solve the problem in the existing method that there is a need to get a reference sample of known transmittance and manufacture two samples of identical transmittance, and the sample transmittance has manufacture error and measurement error. The method comprises the following steps: first, selecting at least three to-be-tested elements according to the transmittance test requirement of a spectrophotometer; then, pairing the to-be-tested elements under a to-be-tested incidence angle, and performing transmittance test to get transmittance values; and finally, using a formula (1) to calculate the transmittance value of each to-be-tested element under the to-be-tested incidence angle based on the obtained transmittance values. By using the method, the transmittance of multiple unknown samples can be obtained at the same time, and the accuracy of measurement is high.

Description

A kind of method for determining optical component transmitance under non-normal incidence condition

Technical field

The invention belongs to optical component field, being specifically related to a kind of method for determining optical component transmitance under non-normal incidence condition.

Background technology

Adopt the transmitance of photometer measuring optical element, need sample to be placed in photometric light path.When measured transmitance is normal incidence, emergent ray does not change, and therefore test result is free from error transmitance.If but needed the transmitance under measurement anon-normal condition of incidence, because sample exists certain inclination angle relative to incident ray, therefore incident ray could produce refraction on testing sample surface and cause direction to change.For addressing this problem, to need with the plane perpendicular to incident light, for axis, to place another auxiliary element in the mirror position of sample.Like this, incident light is successively after testing sample and auxiliary sample, and its direction does not still produce change.What adopt this kind of method to obtain is the tandem compound transmitance of testing sample and auxiliary sample.

Adopt in this way, there is Railway Project: first, because the tandem compound transmitance of testing sample and auxiliary sample when measuring the transmitance obtained, instead of the transmitance of testing sample self, so the transmitance of auxiliary sample also must be known in advance, the transmitance of testing sample itself can be calculated; Second, auxiliary sample due to known transmitance is difficult to obtain usually, so usually adopting alternative method, namely under similarity condition, make two and be regarded as the identical element of transmitance, measure their tandem compound transmitance, then calculate single transmitance, and in practice, the sample that two transmitances are identical is difficult to make; 3rd, in making and measuring process, can inevitably there is fabrication error, measuring error in any optical element, therefore adopts said method to be usually difficult to obtain element transmitance.

Summary of the invention

The object of the invention is to solve reference sample that existing method needs transmitance known, need making two on all four samples of transmitance, problem that sample transmitance exists fabrication error and measuring error, and provide a kind of method for determining optical component transmitance under non-normal incidence condition.

The invention provides a kind of method for determining optical component transmitance under non-normal incidence condition, the method comprises:

Step one: according to spectrophotometric transmission measurement requirement, choose at least three element under tests;

Step 2: under incident angle to be measured, matches between two by original paper to be measured, then carries out transmission measurement respectively, obtains transmitance numerical value;

Step 3: the transmitance numerical value obtained according to step 2, utilizes formula (1), calculates under this treats measuring angle, the transmitance numerical value of each original paper to be measured;

In formula (1), x represents the quantity of testing sample element.

Beneficial effect of the present invention

The invention provides a kind of method for determining optical component transmitance under non-normal incidence condition, the method is by the combination of two transmission measurement to multiple element (number of elements is more than three), utilize these combination transmitances can calculate the transmitance result of each element, when number of elements is four or more, possible combination of two number has exceeded the number of element, therefore least square method can have been adopted to draw and to have rejected the result of error, achieve higher Transmissivity measurement degree of confidence.Compare with prior art, the method adopted in the present invention is without the need to realizing the transmitance knowing any one sample, and constraint condition that also must be identical without any two sample transmitances, reduces the workload required for preparation of samples; When the sample number participating in test is more, the multiple measurement number more than sample number can be adopted to carry out least square method, effectively prevent the uncertainty that preparation error and measuring error are at random brought, can obtain the transmitance of multiple unknown sample, accuracy of measurement is high simultaneously.

Accompanying drawing explanation

Fig. 1 is transmission measurement specimen holder schematic diagram of the present invention.

Embodiment

The invention provides a kind of method for determining optical component transmitance under non-normal incidence condition, the method comprises:

Step one: according to spectrophotometric transmission measurement requirement, choose at least three element under tests;

Step 2: under incident angle to be measured, matches between two by original paper to be measured, and series connection is positioned on specimen holder, then carries out transmission measurement respectively, namely measures the tandem compound transmitance under a certain incident angle, obtain transmitance numerical value; As shown in Figure 1, be positioned on specimen holder by original paper 1 to be measured and original paper to be measured 2 series connection, 3 is specimen holder base (being placed in during test in photometer sample chamber), measures original paper 1 to be measured and original paper to be measured 2 tandem compound transmitance;

Step 3: the transmitance numerical value obtained according to step 2, utilizes formula (1), calculates under this treats measuring angle, the transmitance numerical value of each original paper to be measured;

In formula (1), x represents the quantity of testing sample element.

In step 2 described in present embodiment, when testing at every turn, incident light successively with same angle successively through two original papers to be measured, record two original papers to be measured connect under this angle after transmitance.

Original paper to be measured described in present embodiment is preferably three or four, and when original paper to be measured is three, marking original paper to be measured is respectively No. 1, No. 2 and No. 3, No. 1, No. 2 sample combination is carried out the 1st test, obtains transmitance T ₁₂; No. 1, No. 3 sample combination carry out the 2nd test, obtain transmitance T ₁₃; No. 2, No. 3 sample combination carry out the 3rd test, obtain transmitance T ₂₃.

When original paper to be measured is four, marking original paper to be measured is respectively No. 1, No. 2, No. 3 and No. 4, then No. 1, No. 2 sample combination carry out the 1st test, obtain transmitance T ₁₂; No. 1, No. 3 sample combination carry out the 2nd test, obtain transmitance T ₁₃; No. 1, No. 4 sample combination carry out the 3rd test, obtain transmitance T ₁₄; No. 2, No. 3 sample combination carry out the 4th test, obtain transmitance T ₂₃; No. 2, No. 4 sample combination carry out the 5th test, obtain transmitance T ₂₄; No. 3, No. 4 sample combination carry out the 6th test, obtain transmitance T ₃₄.

The each transmitance numerical value obtained according to step 2 described in present embodiment, utilizes formula (1), calculates under this treats measuring angle, the transmitance numerical value of each original paper to be measured;

Specifically, when original paper to be measured is three, utilize three the combination transmitance T recorded in second step ₁₂, T ₂₃and T ₁₃, adopt following formula:

Calculate the logarithm value lgT of three elements transmitance separately ₁, lgT ₂and lgT ₃, then obtain T ₁, T ₂and T ₃numerical value.

When original paper to be measured is four, adopt following formula:

LgT ₁, lgT ₂, lgT ₃and lgT ₄be carry out least square method to (2) formula to obtain, then can obtain T ₁, T ₂, T ₃and T ₄numerical value.Obviously, (2) six formula are had in formula, but four unknown numbers are only had, the optimum solution of the logarithm of each element independent measurement transmitance can be solved by least square method, and these optimum solutions have eliminated stochastic error effectively, so just obtain the transmitance of element under non-normal incidence condition.

Below in conjunction with embodiment and accompanying drawing, the invention will be further described.

Embodiment 1

Now for four antireflective film samples that substrate of glass is coated with, illustrate under wavelength is the condition of 632.8nm, when incident angle is 30 degree, the deterministic process of element transmitance.

Step one: according to spectrophotometric transmission measurement requirement, choose No. 1, four element under tests, No. 2, No. 3 and No. 4;

Four element under tests are matched by step 2: under incident angle to be measured between two, No. 1, No. 2 sample combination are carried out the 1st test, obtain transmitance T ₁₂be 98.2%; No. 1, No. 3 sample combination carry out the 2nd test, obtain transmitance T ₁₃be 98.7%; No. 1, No. 4 sample combination carry out the 3rd test, obtain transmitance T ₁₄be 98.3%; No. 2, No. 3 sample combination carry out the 4th test, obtain transmitance T ₂₃t ₁₂be 98.5%; No. 2, No. 4 sample combination carry out the 5th test, obtain transmitance T ₂₄t ₁₂be 98.1%; No. 3, No. 4 sample combination carry out the 6th test, obtain transmitance T ₃₄t ₁₂be 98.6%;

Step 3: utilize each transmitance result obtained in step 2, according to formula (2), calculates under this treats measuring angle, each testing sample transmitance numerical value separately;

Obtain lgT ₁=-0.00349, lgT ₂=-0.00436, lgT ₃=-0.00218 and lgT ₄=-0.00393.It can thus be appreciated that T ₁=99.2%, T ₂=99.0%, T ₃=99.5% and T ₄=99.1%.

Claims (2)

1., for determining a method for optical component transmitance under non-normal incidence condition, it is characterized in that, the method comprises:

Step one: according to spectrophotometric transmission measurement requirement, choose at least three element under tests;

Step 2: under incident angle to be measured, matches between two by original paper to be measured, then carries out transmission measurement respectively, obtains transmitance numerical value;

Step 3: the transmitance numerical value obtained according to step 2, utilizes formula (1), calculates under this treats measuring angle, the transmitance numerical value of each original paper to be measured;

$\left(\begin{array}{cccccc}1& 1& 0& \·& \·& 0\\ 1& 0& 1& \·& \·& 0\\ 1& 0& 0& \·& \·& 0\\ \·& \·& \·& & & \·\\ \·& \·& \·& & & \·\\ 0& 0& 0& \·& 1& 1\end{array}\right)\left(\begin{array}{c}\lg T_1\\ \lg T_2\\ \lg T_3\\ \·\\ \·\\ \lg T_x\end{array}\right)=\left(\begin{array}{c}\lg T_{12}\\ \lg T_{13}\\ \lg T_{14}\\ \·\\ \·\\ \lg T_{(x-1)\left(x\right)}\end{array}\right)---\left(1\right)$

In formula (1), x represents the quantity of testing sample element.

2. a kind of method for determining optical component transmitance under non-normal incidence condition according to claim 1, it is characterized in that, described element under test is 3 or 4.