Method for testing optical density of absorption type laser protective goggles

Abstract

The invention provides a method for testing the optical density of an absorption type laser goggles, and relates to the technical field of laser detection. The method for testing the optical density of the absorption type laser protective goggles comprises the following specific steps: S1, placing equipment: sequentially placing a laser light source, an attenuator, a polarization beam splitter prism, an aperture diaphragm I, a semi-transparent and semi-reflective prism, a photoelectric detector I, an aperture diaphragm II and a photoelectric detector II, other parts are arranged on the same straight line; s2, setting a light source: turning on a laser light source and preheating; and S3, releasing the light source: opening the aperture diaphragm I, and enabling the emergent light beam of the laser light source to enter the polarization beam splitter prism through the attenuator. A device for generating linear polarized light and monitoring the polarization state of a light beam entering the surface of the protective glass is introduced into a test light path, so that laser energy before and after a to-be-detected product is added does not generate large fluctuation, and the accuracy of an optical density detection result is further improved.

Description

Technical Field

[0001] The present invention relates to the field of laser detection technology, in particular to a method for testing the optical density of absorption-type laser protective goggles. Background Art

[0002] Laser radiation can cause damage to the eyes and face of people accidentally exposed. During the development, production, and use of lasers, eye and face safety is crucial, and users are required to wear eye and face protection. In recent years, various types of laser protective lenses with different operating principles have been widely used on the market. However, optical density remains a key indicator for evaluating the safety and reliability of laser protective goggles, making it particularly important to accurately and effectively test the optical density of laser protective lenses.

[0003] At present, there are two mainstream methods for detecting the optical density value of laser protective lenses. One is to use a semi-transparent, semi-reflective beam splitter to compare the laser power of the transmitted light path and the reflected light path to calculate the optical density value, that is, the logarithm of the ratio of the power of the transmitted light of the semi-transparent, semi-reflective prism passing through the laser protective lens to the power of the reflected light of the semi-transparent, semi-reflective prism.

[0004] The other method is simpler and cruder. It records the energy of the light source irradiating the detector surface before and after adding protective glasses, and then compares them. Both of the above methods ignore two key issues. First, how to ensure that the polarization state of the incident light during the detection process is linearly polarized. As we all know, in the optical density test process, only when the incident light beam is linearly polarized can the accuracy of the subsequent test results be guaranteed. Second, the energy of the laser will inevitably fluctuate to varying degrees within a certain time range. There is a difference in the output energy of the light source between the two irradiations with and without protective glasses. The 50:50 splitting of the semi-transparent and semi-reflective prism is only a reference value, not an absolute value. In addition, the absorption rate of the semi-transparent and semi-reflective prism to the spectrum is different.

[0005] To this end, we have developed a new method for testing the optical density of absorption laser protective goggles. Summary of the Invention

[0006] (1) Technical problems solved

[0007] In response to the shortcomings of the existing technology, the present invention provides a method for testing the optical density of absorptive laser protective goggles, which solves the problems in the existing technology of low test accuracy caused by different light source output energies before and after the installation of the test object and different absorption rates of the semi-transparent and semi-reflective prisms to the spectrum.

[0008] (2) Technical solution

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for testing the optical density of absorption laser protective glasses, comprising the following specific steps:

[0010] S1. Arrange the equipment: Place the laser light source, attenuator, polarization beam splitter, aperture stop 1, semi-transparent and semi-reflective prism, photodetector 1, aperture stop 2, and photodetector 2 in order. Except for photodetector 1, all other components are coaxially arranged.

[0011] S2. Set the light source: turn on the laser light source and preheat it;

[0012] S3. Release the light source: Open aperture 1, and the outgoing beam of the laser light source passes through the attenuator and enters the polarization beam splitter prism;

[0013] S4. Adjust the optical path and read the reading: Rotate the polarizing beam splitter prism while observing the reading of the photodetector. Stop rotating the polarizing beam splitter prism when the reading of the photodetector reaches the maximum value, and lock it.

[0014] S5. Primary recording: Open aperture diaphragm 2, and the light beam in the optical path passes through the transmission surface of the semi-transparent and semi-reflective prism and enters photodetector 2. The laser powers detected by photodetector 1 and photodetector 2 are read simultaneously and recorded as P1 and P2, respectively.

[0015] S6. Install the test object: Add a laser protective goggles to the test object between the second aperture stop and the second photodetector, so that the second aperture stop, the laser protective goggles and the second photodetector are in a straight line;

[0016] S7, secondary recording: reading the laser powers detected by the first photodetector and the second photodetector simultaneously again, and recording them as P3 and P4 respectively;

[0017] S8. Calculate the values: Substitute P1, P2, P3, and P4 from the two records into the formula for calculating the optical density OD (λ) of the protective lens at a specific wavelength:

[0018]

[0019] The final optical density OD (λ) was calculated according to the formula.

[0020] Preferably, the photodetector 1 in S1 is arranged on one side of the semi-transparent and semi-reflective prism, and the line between the photodetector 1 and the semi-transparent and semi-reflective prism is perpendicular to the straight line where the other components are located.

[0021] Preferably, the attenuation accuracy of the attenuator selected in S1 is positively correlated with the brightness of the laser light source.

[0022] Preferably, the light-clearing diameter of the aperture stop 1 in S1 is between φ4 mm and φ7 mm, and the light-clearing diameter of the aperture stop 2 is φ3.5 mm.

[0023] Preferably, the time for preheating the light source in S2 exceeds 30 minutes.

[0024] Preferably, the main vibration direction of the light beam emitted by the laser light source in S4 is consistent with the fast axis direction of the polarization beam splitter prism.

[0025] Preferably, a rotating mount is provided at the bottom of the polarization beam splitter prism in the S4, and the model of the rotating mount is PRM05.

[0026] Preferably, the distance between the laser protective mirror and the aperture stop 2 in S6 is smaller than the distance between the laser protective mirror and the photodetector 2.

[0027] (3) Beneficial effects

[0028] The present invention provides a method for testing the optical density of absorption-type laser protective goggles. It has the following beneficial effects:

[0029] 1. The present invention introduces a device for generating linear polarized light and for monitoring the polarization state of the light beam incident on the surface of the protective mirror into the test optical path, so that the light beam in the up and down vibration direction of the laser light source is emitted from the output end of the polarization beam splitter prism, and the other part containing a small amount of light beam in the up and down vibration direction, together with the light beam vibrating inward and outward perpendicular to the optical axis, is filtered out from the side of the polarization beam splitter prism. The filtered light beam does not participate in the detection, so only the light beam vibrating inward and outward is retained. The laser energy before and after the addition of the test sample will not produce large fluctuations, thereby improving the accuracy of the optical density test results.

[0030] 2. The calculation formula in this application is the core formula for calculating optical density Derived from this, the transmitted light intensity I(λ) and the incident light intensity I 0( The four numbers P1, P2, P3 and P4 are converted into P1, P2, P3 and P4 which can be read intuitively in the experiment. At the same time, these four numbers have their own meanings. P1 represents the power or energy of the light path reflected by the semi-transparent and semi-reflective prism when there is no protective glass. P2 represents the power or energy of the light path transmitted by the semi-transparent and semi-reflective prism when there is no protective glass. P3 represents the power or energy of the light path reflected by the semi-transparent and semi-reflective prism when there is a protective glass. P4 represents the power or energy of the light path transmitted by the semi-transparent and semi-reflective prism when there is a protective glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Example 1:

[0034] like Figure 1 As shown, an embodiment of the present invention provides a method for testing the optical density of an absorptive laser protective goggles, comprising the following specific steps:

[0035] S1. Arrange the equipment: Place the laser light source, attenuator, polarization beam splitter, aperture stop 1, semi-transparent and semi-reflective prism, photodetector 1, aperture stop 2, and photodetector 2 in order. Except for photodetector 1, all other components are coaxially arranged.

[0036] S2. Set the light source: turn on the laser light source and preheat it;

[0037] S3. Release the light source: Open aperture 1, and the outgoing beam of the laser light source passes through the attenuator and enters the polarization beam splitter prism;

[0038] S4. Adjust the optical path and read the reading: Rotate the polarizing beam splitter prism while observing the reading of the photodetector. Stop rotating the polarizing beam splitter prism when the reading of the photodetector reaches the maximum value, and lock it.

[0039] S5. Primary recording: Open aperture diaphragm 2, and the light beam in the optical path passes through the transmission surface of the semi-transparent and semi-reflective prism and enters photodetector 2. The laser powers detected by photodetector 1 and photodetector 2 are read simultaneously and recorded as P1 and P2, respectively.

[0040] S6. Install the test object: Add a laser protective goggles with a nominal OD4 between the aperture stop 2 and the photodetector 2, so that the aperture stop 2, the laser protective goggles and the photodetector 2 are in a straight line;

[0041] S7, secondary recording: reading the laser powers detected by the first photodetector and the second photodetector simultaneously again, and recording them as P3 and P4 respectively;

[0042] S8. Calculate the values: Substitute P1, P2, P3, and P4 from the two records into the formula for calculating the optical density OD (λ) of the protective lens at a specific wavelength:

[0043]

[0044] The final optical density OD (λ) was calculated according to the formula.

[0045] Example 2:

[0046] This embodiment differs from the first embodiment in that a method for testing the optical density of an absorptive laser protective goggles includes the following specific steps:

[0047] S1. Arrange the equipment: Place the laser light source, attenuator, polarization beam splitter prism, aperture stop 1, semi-transparent and semi-reflective prism, photodetector 1, aperture stop 2, and photodetector 2 in order. Except for photodetector 1, all other components are coaxially arranged.

[0048] S2. Set the light source: turn on the laser light source and preheat it;

[0049] S3. Release the light source: Open aperture 1, and the outgoing beam of the laser light source passes through the attenuator and enters the polarization beam splitter prism;

[0050] S4. Adjust the optical path and read the reading: Rotate the polarizing beam splitter prism while observing the reading of the photodetector. Stop rotating the polarizing beam splitter prism when the reading of the photodetector reaches the maximum value, and lock it.

[0051] S5. Primary recording: Open aperture diaphragm 2, and the light beam in the optical path passes through the transmission surface of the semi-transparent and semi-reflective prism and enters photodetector 2. The laser powers detected by photodetector 1 and photodetector 2 are read simultaneously and recorded as P1 and P2, respectively.

[0052] S6. Install the test object: Add a laser protective goggles with a nominal OD of 4.5 between the aperture stop 2 and the photodetector 2, so that the aperture stop 2, the laser protective goggles and the photodetector 2 are in a straight line;

[0053] S7, secondary recording: reading the laser powers detected by the first photodetector and the second photodetector simultaneously again, and recording them as P3 and P4 respectively;

[0054] S8. Calculate the values: Substitute P1, P2, P3, and P4 from the two records into the formula for calculating the optical density OD (λ) of the protective lens at a specific wavelength:

[0055]

[0056] The final optical density OD (λ) was calculated according to the formula.

[0057] Example 3:

[0058] This embodiment differs from the first embodiment in that a method for testing the optical density of an absorptive laser protective goggles includes the following specific steps:

[0059] S1. Arrange the equipment: Place the laser light source, attenuator, polarization beam splitter prism, aperture stop 1, semi-transparent and semi-reflective prism, photodetector 1, aperture stop 2, and photodetector 2 in order. Except for photodetector 1, all other components are coaxially arranged.

[0060] S2. Set the light source: turn on the laser light source and preheat it;

[0061] S3. Release the light source: Open aperture 1, and the outgoing beam of the laser light source passes through the attenuator and enters the polarization beam splitter prism;

[0062] S4. Adjust the optical path and read the reading: Rotate the polarizing beam splitter prism while observing the reading of the photodetector. Stop rotating the polarizing beam splitter prism when the reading of the photodetector reaches the maximum value, and lock it.

[0063] S5. Primary recording: Open aperture diaphragm 2, and the light beam in the optical path passes through the transmission surface of the semi-transparent and semi-reflective prism and enters photodetector 2. The laser powers detected by photodetector 1 and photodetector 2 are read simultaneously and recorded as P1 and P2, respectively.

[0064] S6. Install the test object: Add a laser protective goggles with a nominal OD5 between the aperture stop 2 and the photodetector 2, so that the aperture stop 2, the laser protective goggles and the photodetector 2 are in a straight line;

[0065] S7, secondary recording: reading the laser powers detected by the first photodetector and the second photodetector simultaneously again, and recording them as P3 and P4 respectively;

[0066] S8. Calculate the values: Substitute P1, P2, P3, and P4 from the two records into the formula for calculating the optical density OD (λ) of the protective lens at a specific wavelength:

[0067]

[0068] The final optical density OD (λ) was calculated according to the formula.

[0069] Comparative Example:

[0070] The commonly used method for testing optical density is to use a spectrophotometer to measure it. The specific steps are as follows:

[0071] S1. Preheating and calibration: Turn on the spectrophotometer and preheat it according to the instructions to ensure that the light source and detector are stable. At the same time, perform instrument self-test and calibration.

[0072] S2. Set the wavelength: Set it on the instrument according to the nominal protection wavelength range of the protective glasses or the specific wavelength λ that needs to be detected. If it is in scanning mode, set the scanning range and step size;

[0073] S3. Measure the incident light intensity I0(λ): Do not place any sample for "baseline calibration". The instrument will automatically record the light intensity at this time as I0(λ), or set the transmittance T at this time to 100% (absorbance / OD to 0);

[0074] S4. Measure the transmitted light intensity I(λ): Place the protective goggles sample (OD 4.5) to be measured vertically in the sample compartment in the light path, ensuring that the light beam passes through the effective area of the protective goggles. The instrument detector will measure the light intensity I(λ) after passing through the protective goggles.

[0075] S5. Reading: The instrument usually directly calculates and displays the absorbance (A) at the wavelength. In the field of optics, especially in protective goggles standards, optical density (OD) is usually equivalent to absorbance (A), so the optical density (OD) can be directly calculated.

[0076] Each of the above examples and comparative examples adopts the method of taking the average value of multiple experiments to obtain the average OD. By comparing the OD values of Example 1, Example 2, Example 3 and the comparative example, the following table can be obtained:

[0077] Example Nominal OD Measured OD Example 1 4 4 Example 2 4.5 4.5 Example 3 5 5 Comparative Example 4.5 4.7

[0078] In summary, the present invention introduces a device for generating linear polarized light and monitoring the polarization state of the light beam incident on the surface of the protective mirror into the test optical path, as well as a device for respectively detecting the laser power value of the transmission optical path of the semi-transparent and semi-reflective prism and the laser power value of the reflected optical path, thereby improving the accuracy of the optical density detection results.

[0079] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for testing the optical density of absorption laser protective goggles, characterized in that: The specific steps include: S1. Arrange the equipment: Place the laser light source, attenuator, polarization beam splitter, aperture stop 1, semi-transparent and semi-reflective prism, photodetector 1, aperture stop 2, and photodetector 2 in order. Except for photodetector 1, all other components are coaxially arranged. S2. Set the light source: turn on the laser light source and preheat it; S3. Release the light source: Open aperture 1, and the outgoing beam of the laser light source passes through the attenuator and enters the polarization beam splitter prism; S4. Adjust the optical path and read the reading: Rotate the polarizing beam splitter prism while observing the reading of the photodetector. Stop rotating the polarizing beam splitter prism when the reading of the photodetector reaches the maximum value, and lock it. S5. Primary recording: Open aperture diaphragm 2, and the light beam in the optical path passes through the transmission surface of the semi-transparent and semi-reflective prism and enters photodetector 2. The laser powers detected by photodetector 1 and photodetector 2 are read simultaneously and recorded as P1 and P2, respectively. S6. Install the test object: Add a laser protective goggles to the test object between the second aperture stop and the second photodetector, so that the second aperture stop, the laser protective goggles and the second photodetector are in a straight line; S7, secondary recording: reading the laser powers detected by the first photodetector and the second photodetector simultaneously again, and recording them as P3 and P4 respectively; S8. Calculate the values: Substitute P1, P2, P3, and P4 from the two records into the formula for calculating the optical density OD (λ) of the protective lens at a specific wavelength: The final optical density OD (λ) was calculated according to the formula.

2. The method for testing the optical density of an absorption-type laser protective goggles according to claim 1, wherein: The photoelectric detector 1 in S1 is arranged on one side of the semi-transparent and semi-reflective prism, and the line connecting the photoelectric detector 1 and the semi-transparent and semi-reflective prism is perpendicular to the straight line where the other components are located.

3. The method for testing the optical density of an absorption laser protective goggles according to claim 1, wherein: The attenuation accuracy of the attenuator selected in S1 is positively correlated with the brightness of the laser light source.

4. The method for testing the optical density of an absorption laser protective goggles according to claim 1, wherein: The aperture of aperture stop 1 in S1 is between φ4 mm and φ7 mm, and the aperture of aperture stop 2 is φ3.5 mm.

5. The method for testing the optical density of an absorption laser protective goggles according to claim 1, wherein: The time for preheating the light source in S2 exceeds 30 minutes.

6. The method for testing the optical density of an absorption laser protective goggles according to claim 1, wherein: The main vibration direction of the light beam emitted by the laser light source in S4 is consistent with the fast axis direction of the polarization beam splitter prism.

7. The method for testing the optical density of absorption laser protective goggles according to claim 1, wherein: A rotating mounting base is provided at the bottom of the polarization beam splitter prism in the S4, and the model of the rotating mounting base is PRM05.

8. The method for testing the optical density of absorption laser protective goggles according to claim 1, wherein: In the S6, the distance between the laser protective mirror and the second aperture stop is smaller than the distance between the laser protective mirror and the second photodetector.

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