CN85101719A - Measure the method and apparatus of high reflectance - Google Patents

Abstract

The present invention adds the repeatedly method and apparatus of reflection unit measurement minute surface high reflectance of symmetric resonator on spectrophotometer.Symmetric resonator is placed on can locate on the disk that rotates 180 °, and high reflectance is to pass through formula

Description

Measure the method and apparatus of high reflectance

One, measures the method for high reflectance

The method of measurement of reflectivity is one of the important method in optic test field.

The present invention adds the repeatedly method of reflection unit measurement minute surface high reflectance of symmetric resonator on spectrophotometer.

The method of existing repeatedly reflection measurement high reflectance (seeing JOSAVo1,51, P164,1961) is seen Fig. 1, and (1) is plane mirror, and (4) are spherical reflectors, and (2) are the identical measured samples of reflectivity with (3).When measured sample (2) and (3) are in position among the figure; Photoelectric reading is E, then reflectivity R ⁸=KE ₁, K is an instrument constant; Sample (3) is when being in dotted line position, and photoelectric reading is E ₂, reflectivity R then ⁸=KE ₂, try to achieve reflectivity R=at last $\sqrt{E{}_1\mathrm{/\; <figure-callout\; id="2"\; label="E"\; filenames="85101719\_DRIMG1.png,85101719\_DRIMG2.png"\; state="\{\{state\}\}">E</figure-callout>}{}_2}$ 。

As long as sample size is enough big, the order of reflection of the method can increase, but sample is placed precision harsher requirement is arranged, otherwise because the difference of receiver sensitivity can produce bigger measuring error; On the other hand, can see that process of measurement is quite complicated.Obviously, require to implement to measure in the finite space of twin-beam spectrophotometer measuring chamber, can not add integrating sphere again, as seen the method for above-mentioned repeatedly reflection measurement high reflectance is inapplicable.

In order to overcome the shortcoming of above-mentioned measurement high reflectance method, we have invented a kind of method of repeatedly reflection measurement high reflectance, see Fig. 2, rotate on 180 ° of garden dishes (6) in the location, coaxial relatively placement spacing is that L(L is that a diameter is coiled in the garden), radius-of-curvature is that spherical reflector (1) and (3) of γ constitute symmetric resonator, light forms repeatedly reflection in the chamber, wherein, curvature γ and spacing L satisfy formula, L=(1-Cos (n)/(N)), N=2,3,4 ...By opening P * q slotted hole in the spherical reflector center.The monochromator exit slit of spectrophotometer resembles the slotted hole place incident that drops on spherical reflector (3) through plane mirror (5) reflection, through spherical reflector (1) reflection N time, after spherical reflector (3) reflection (N-1) is inferior, light becomes the slotted hole place outgoing of slit image in spherical reflector (3) again, spherical reflector (4) is this emergent light reflection, it is propagated along the direction of former measuring beam, measuring samples (2) is placed by rotating disk (6) rotation and vertical with the optical axis of symmetric resonator, then incident light is through sample (2) reflection 2N time, and spherical reflector (3) reflects (2N-1) inferior outgoing.

The reflectivity of measuring samples (2) records like this: establish that sample (2) places before the light path and after measure photosignal and be respectively E ₁And E ₂; The positions of (6) 180 ° of positioning of rotating rotating disks exchange spherical reflector (1) and (3), at this moment sample (2) place before the light path with after the photosignal measured be respectively E ₃And E ₄, then the sample reflectivity is R=4N $\sqrt{E{}_2\mathrm{<figure-callout\; id="4"\; label="E"\; filenames="85101719\_DRIMG1.png,85101719\_DRIMG2.png"\; state="\{\{state\}\}">E</figure-callout>}{}_4\mathrm{/\; E}{}_1\mathrm{<figure-callout\; id="3"\; label="E"\; filenames="85101719\_DRIMG1.png"\; state="\{\{state\}\}">E</figure-callout>}{}_3}$ 。

Two, measure the device of high reflectance.

Based on the method for aforementioned invention measurement high reflectance, we invent a kind of device of measuring high reflectance, are contained in the spectrophotometer measuring chamber, can do repeatedly reflection measurement high reflectance.

Measure the device of high reflectance, see figure (2).It is by spherical reflector (4), plane mirror (5), and be placed on the symmetric resonator composition that the location spherical reflector (1) that to rotate two same curvature radiuses on 180 ° the garden dish (6) be γ and (3) form; By the location rotating disk rotation of (6) and vertical, place and measure high reflectance sample (2) with the symmetric resonator optical axis.

On the garden dish (6) of 180 ° of the location rotations of measuring the high reflectance device, cut-off directly is the coaxial relatively placement spherical reflector of the two-end-point of L (1) and (3), has P * q slotted hole by the spherical reflector center.

The method and apparatus of measurement high reflectance of the present invention can become the multiple function apparatus that can measure high reflectance and transmitance with the double beam spectrophotometer that can only measure transmitance, and sample placement accuracy requirement is not high, and process of measurement is simple.The measuring accuracy of the former instrument transmitance of high reflection rate measurement ratio of precision improves nearly 2N doubly.

Most preferred embodiment is seen accompanying drawing 3, and this is by the wide X=110mm of measuring chamber, and reference beam R and measuring beam S distance Y=100mm design.Because reference path in this measurement high reflectance device and measurement light path have symmetrical structure, so only the structure of light path is measured in narration.

Measuring on the high reflectance device, in measuring (reference) light beam, apart from measuring chamber left side wall X ₁It is the plane by one side that=16mm disposes one, and another side is the dihedral angle mirror (1) that sphere constituted, diagram X₁=30 °, dihedral angle is 96.47 °, and its sphere curvature radius is 110mm; At range observation (reference) light beam Y ₁=50mm and left chamber distance X ₂=62.5mm place designs a garden that horizontally rotates with 180 ° of detent mechanisms and coils (5), get spherical reflector (2) and (4) that a diameter is placed radius-of-curvature γ=221.9mm for the L=65mm two-end-point thereon, open P * q=22 * 2(mm) at 2mm place, distance mirror center ²The hole, the optical axis of two spherical reflectors (2) and (4) becomes angle α with the measuring chamber light beam ₂=53.13 °.Eight light of high reflectance sample (2) reflection are measured in above-mentioned design.

This measurement high reflectance device can be placed in the measuring chamber of twin-beam spectrophotometer of more existing visible ranges, also can cooperate monochromator and photoelectric receiving system to carry out measurement of reflectivity with monochromatic light road form.

Claims (4)

1, a kind of method of measuring high reflectance is repeatedly the method for reflection measurement, it is characterized in that repeatedly the reflection measurement method adopts resonator cavity reflection configuration α repeatedly.

2, by the method for the described measurement high reflectance of claim 1, it is characterized in that: with symmetric resonator repeatedly reflection configuration place one can locate on the plane of rotating 180 °, reflectivity is by photosignal E ₁, E ₂, E ₃And E ₄, by formula R=4N $\sqrt{E{}_{2}E{}_4\mathrm{/\; E}{}_{1}E{}_2}$ Try to achieve.

3, a kind of device of measuring high reflectance, comprise level crossing and spherical mirror, the device that it is characterized in that measuring high reflectance is by plane mirror (5), spherical reflector (4) and be placed on the location spherical reflector (1) that to rotate two same curvature radiuses on 180 ° the garden dish (6) be γ and symmetric resonator that (3) form is formed; Rotation and the vertical high reflectance sample (2) of placing by location rotation garden dish (6) with the symmetric resonator optical axis.

4, by the device of the described measurement high reflectance of claim 3, it is characterized in that: on location rotation garden dish (6), cut-off directly is the two-end-point of L, and coaxial relatively placement spherical reflector (1) and (3) have P * q slotted hole by the spherical reflector center.

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