CN110646169B

CN110646169B - Method for measuring reflectivity of curved surface optical film element

Info

Publication number: CN110646169B
Application number: CN201911028735.4A
Authority: CN
Inventors: 王银河; 宋光辉; 姚春龙; 刘海涛; 李明华; 李野
Original assignee: Shenyang Academy of Instrumentation Science Co Ltd
Current assignee: Shenyang Academy of Instrumentation Science Co Ltd
Priority date: 2019-10-28
Filing date: 2019-10-28
Publication date: 2022-03-08
Anticipated expiration: 2039-10-28
Also published as: CN110646169A

Abstract

The invention belongs to the field of optical thin film element parameter measurement, and particularly relates to a method for measuring the reflectivity of a curved optical thin film element, which is implemented according to the following steps: a. starting a constant current light source, and testing parameter setting; b. carrying out standard calibration; c. light emitted by the constant current light source enters the optical fiber receiving end after being focused; the light rays are reflected by a mirror surface and then enter the optical integrator, are homogenized by the optical integrator and then enter a receiving optical fiber through an exit port of the optical integrator, and then enter a CCD detector and are processed by a computer to finally obtain spectral reflection data. The invention can solve the problem that light rays with different angles are difficult to collect completely, has accurate reflectivity test and can ensure that different curvature radiuses are tested.

Description

Method for measuring reflectivity of curved surface optical film element

Technical Field

The invention belongs to the field of optical thin film element parameter measurement, and particularly relates to a method for measuring the reflectivity of a curved optical thin film element.

Background

The method for measuring the reflectivity of the optical thin film element is generally measured by using a spectrophotometer, but the spectrophotometer test is generally limited to the reflectivity measurement of a planar optical element. Due to the structural characteristics of the optical system of the device, when the reflectivity of different curved-surface optical film elements is tested, the light spots and the direction change greatly after being reflected by the curved-surface mirror, and the reflected light is difficult to accurately collect, so that accurate measurement cannot be carried out. The reflectivity of the curved optical film element is difficult to measure in the industry, the conventional testing method is difficult to realize, no universal equipment is available in the industry at present for testing, and the reflectivity testing technology has great difficulty.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides the method for measuring the reflectivity of the curved optical film element, which can solve the problem that light rays with different angles are difficult to collect completely, can test the reflectivity accurately and can ensure that the test of the reflectivity of the curved optical film element with different curvature radiuses is carried out.

In order to solve the technical problem, the invention is realized as follows:

a method for measuring the reflectivity of a curved optical thin-film element can be implemented according to the following steps:

a. starting a constant current light source, and testing parameter setting;

b. carrying out standard calibration; when the entrance port of the optical integrator is closed and light cannot enter the optical integrator, the CCD detector cannot enter light, namely, the zero line reference setting is finished; opening an exit port of the optical integrator, directly testing a standard sample reflector, and processing data to obtain hundred-line data;

c. light emitted by the constant current light source enters the optical fiber receiving end after being focused; the light rays are reflected by a mirror surface and then enter the optical integrator, are homogenized by the optical integrator and then enter a receiving optical fiber through an exit port of the optical integrator, and then enter a CCD detector and are processed by a computer to finally obtain spectral reflection data.

As a preferable scheme, in step a of the present invention, the setting of the test parameters includes setting an integration time, referring to a data line, and a test coordinate range.

Furthermore, the optical integrator can adopt an ultra-short distance reflection integrator; the distance between the integrating port of the optical integrator and the surface to be tested is 2-3 mm.

Further, the spherical diameter of the optical integrator is 30 mm.

The invention can solve the problem that light rays with different angles are difficult to collect completely, has accurate reflectivity test and can ensure that different curvature radiuses are tested.

Compared with the prior art, the invention has the following characteristics:

1. the multi-angle reflection integral light collection method comprises the following steps: because the incidence directions of the light rays reflected by the cambered surfaces with different curvatures are different, the conventional converging light path is difficult to collect and transmit, the integrating sphere type collecting device is designed, and the light rays incident at different angles are collected into the integrating sphere through one integrating sphere, so that the problem that the light rays at different angles are difficult to collect completely is solved.

2. Ultra-short distance reflection integrator: the design strong point of optical integrator, the integration mouth with await measuring face distance 2 ~ 3mm, can directly get into optical integrator when light incides curved surface reflection, ultrashort apart from reflection design has guaranteed when testing different radians and the surface of size, the reverberation can get into optical integrator completely, guarantees no light loss, guarantees the reflectivity test accuracy.

3. Small-bore micro-integrator: the micro design of the integrator ensures that the reflectivity of the free curved surfaces with different curvature radiuses can be tested, the spherical diameter of the integrator is only 30mm, and the reflectivity of any curved surface with the specification of 50mm of the minimum curvature radius can be tested.

Drawings

The invention is further described with reference to the following figures and detailed description. The scope of the invention is not limited to the following expressions.

FIG. 1 is a schematic view of the overall structure of the measuring device of the present invention.

Fig. 2 is a schematic diagram of the optical integrator of the present invention.

In the figure: 1. an optical integrator; 2. an incident optical fiber; 3. emergent light; 4. a constant current light source; 5. a CCD detector; 6. an entrance port; 7. an exit port; 8. an optical integrator housing; 9. a curved optical thin film element; 10. and (4) a computer.

Detailed Description

As shown in the figure, the method for measuring the reflectivity of the curved surface optical thin film element is implemented according to the following steps:

a. starting the constant current light source 4, and testing parameter setting;

b. carrying out standard calibration; when the entrance port 6 of the optical integrator 1 is closed and light cannot enter the optical integrator 1, the CCD detector 5 does not have light entering, namely, the zero line reference setting is considered to be finished; opening an exit port 7 of the optical integrator 1, directly testing a standard sample reflector, and processing data to obtain hundred-line data;

c. light emitted by the constant current light source 4 enters an optical fiber receiving end after being focused; the parallel light enters the optical integrator 1 and enters the surface of the curved optical film element to be tested 9 according to a certain angle, the light is reflected by a mirror surface and enters the optical integrator 1, the light is homogenized by the optical integrator 1 and enters a receiving optical fiber through an exit 7 of the optical integrator 1, and then enters the CCD detector 5 and is processed by a computer to finally obtain spectral reflection data.

In step a of the invention, the setting of the test parameters comprises setting of the integration time, the reference data line and the test coordinate range. The optical integrator 1 of the invention adopts an ultra-short distance reflection integrator; the distance between the integrating port of the optical integrator and the surface to be tested is 2-3 mm. The spherical surface diameter of the integrator is 30 mm.

The invention researches a set of method for detecting the reflectivity of a free-form surface with an integral structure. The method is mainly characterized in that light emitted by a constant current light source 4 enters an optical fiber receiving end after being focused, parallel light is emitted after passing through an optical fiber lens, the parallel light is emitted to the surface of a curved surface optical thin film element 9 to be tested according to a certain angle, the light enters an optical integrator 1 after being reflected by a mirror surface, and because the distance between the opening of the optical integrator 1 and the surface to be tested is short, the light can all enter the integrator after being reflected by a free curved surface although the reflection angles are different, the light can be homogenized by the optical integrator, then enters a receiving optical fiber through the exit of the optical integrator, enters a CCD detector and finally obtains spectral reflection data. In the test process, the light outlet of the integrator is aligned to the test curved surface, the reflectivity data can be read after the spectral curve is stably output, and the reflectivity data is stored in the data table.

The equipment structure of the invention is as follows:

(1) computer and test software: the spectrum testing software can use general spectrum testing software and can be also designed in a programming mode. The test software communicates with the CCD detector and converts the received electrical signals into data. Meanwhile, functions such as a reference line, integration time, data calculation and the like can be set.

(2) Incident and exit fibers: the optical fiber adopts thinner ultraviolet optical fiber, can transmit optical signals with different wavelengths of 200 nm-1000 nm, can test the spectral wavelength range of near ultraviolet-visible-near infrared, and has the main function of transmitting incident light and emergent light.

(3) Constant current light source: the constant current light source comprises halogen and ultraviolet light sources, can generate stable light output, and cannot generate stroboflash or unstable jitter.

(4) A CCD detector: the CCD detector is mainly used for receiving optical signals and converting the optical signals into electric signals, and the electric signals are processed to form percentage data of transmissivity or reflectivity.

(5) Fiber lens: the optical fiber lens is mainly used for forming collimated light beams or converging divergent light, when light of a light source enters the optical integrator through the optical fiber and then is emitted, the light beams need to be ensured to return to the optical integrator, and collimated parallel light beams need to be used; the light emitted by the optical integrator enters the optical fiber through the lens, so that enough energy is ensured to be transmitted into the CCD detector, and the light is converged by the lens.

(6) Standard sample mirror: the standard sample mirror is a full spectrum high reflection mirror, has high reflectivity to the spectrum of the test wave band, and is a reference sample wafer for making hundreds of lines.

It should be understood that the detailed description of the present invention is only for illustrating the present invention and is not limited by the technical solutions described in the embodiments of the present invention, and those skilled in the art should understand that the present invention can be modified or substituted equally to achieve the same technical effects; as long as the use requirements are met, the method is within the protection scope of the invention.

Claims

1. A method for measuring the reflectivity of a curved optical thin-film element is characterized by comprising the following steps:

a. starting a constant current light source (4), and testing parameter setting; setting test parameters including setting integration time, reference data lines and test coordinate ranges;

b. carrying out standard calibration; when the entrance port (6) of the optical integrator (1) is closed and light cannot enter the optical integrator (1), the CCD detector (5) does not have light entering, namely, the zero line reference setting is considered to be finished; opening an emergent port (7) of the optical integrator (1), directly testing a standard sample reflector, and processing data to obtain hundred-line data; the optical integrator (1) adopts an ultra-short distance reflection integrator; the distance between an integrating port of the optical integrator (1) and a surface to be tested is 2-3 mm; the spherical surface diameter of the optical integrator (1) is 30 mm;

c. light emitted by the constant current light source (4) enters an optical fiber receiving end after being focused; the light is homogenized by the optical integrator (1), enters a receiving optical fiber through an exit port of the optical integrator (1), enters a CCD detector (5) and is processed by a computer (10) to finally obtain spectral reflection data.