Device for measuring absorbance of LED light source

Abstract

The invention discloses an LED light source absorbance measuring device which comprises an LED light source, an absorbance flow cell and a detector, the absorbance flow cell comprises a reflection panel, a bottom panel, an upper panel and a side panel, the bottom panel, the upper panel and the side panel enclose to form the absorbance flow cell, the reflection panel is located in the absorbance flow cell, and the detector is located in the absorbance flow cell. The reflecting panel is parallel to the bottom panel and the upper panel, a plurality of reflecting rings are nested in the reflecting panel, the flow cell inlet and the flow cell outlet are respectively arranged on the side panels, and the LED light source and the detector are symmetrically arranged up and down relative to the reflecting panel. According to the device designed by the invention, the light intensity measurement value can be conveniently and accurately obtained as long as the detector is placed at the symmetrical position (symmetrical about the reflection panel) of the light source.

Description

Technical Field

[0001] The invention patent relates to the field of optical measurement, specifically to the field of LED light source absorbance measurement. Background Art

[0002] Usually, LEDs have a certain divergence angle, and the light intensity distribution at different divergence angles is also different. In the absorbance measurement process, it is usually necessary to keep the optical path unchanged, so higher requirements are placed on the collimation of the light source. With the popularization of LED light sources, when LED surface light sources and scattered light sources are used in the field of absorbance measurement, the light source needs to be lens-encapsulated first to make it a collimated or approximately collimated light source, which greatly increases the preparation cost of the LED light source. How to solve such problems efficiently and at low cost has always been a practical need that needs to be solved urgently. In theory, for non-collimated light sources, absorbance measurement can be achieved by establishing a theoretical model or preliminary experimental measurements. Based on this direction, this patent will provide a measuring device and method for the absorbance of an LED light source with a certain divergence angle. Summary of the Invention

[0003] The present invention utilizes multiple micro-small reflective surfaces to reflect the light emitted by the light source one by one and re-converge it at the detector, which not only solves the light collimation problem of the light source, but also solves the problem of light source convergence at the detection point.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a device for measuring the absorbance of an LED light source, comprising an LED light source, an absorbance flow cell and a detector, wherein the absorbance flow cell comprises a reflective panel, a bottom panel, an upper panel and a side panel, and the bottom panel, the upper panel and the side panel enclose the absorbance flow cell, the reflective panel is located in the absorbance flow cell, and is arranged parallel to the bottom panel and the upper panel, and multiple reflective rings are nested inside the reflective panel, and also include a flow cell inlet and a flow cell outlet, and the flow cell inlet and the flow cell outlet are respectively arranged on opposite side panels, wherein the LED light source and the detector are placed symmetrically about the reflective panel.

[0005] Furthermore, the divergence angle of the LED light source ranges from 20° to 120°.

[0006] Furthermore, the absorbance flow cell is made of highly transparent quartz glass.

[0007] Furthermore, the detector adopts a photodetector.

[0008] Furthermore, the thickness of the reflective panel is D.

[0009] Furthermore, the LED light source and the detector are placed symmetrically about the reflective panel.

[0010] Furthermore, given the vertical distance d between the bottom panel and the upper panel after deducting the thickness of the reflective panel, the equivalent absorption distance L of light absorption can be obtained through theoretical calculation for LEDs with different divergence angles.

[0011] Furthermore, the test liquid in the circulation pool can not only pass through the space on one side between the reflective panel and the bottom panel, which corresponds to a vertical absorption distance of 0.5d; it can also pass through the space on both sides between the two sides of the reflective panel and the bottom panel and the upper panel, which corresponds to a vertical absorption distance d.

[0012] Furthermore, the flow cell inlet and the flow cell outlet can be designed as dual channels, and one of the channels or both channels can be used according to different optical path lengths (vertical absorption distance 0.5d or vertical absorption distance d).

[0013] Furthermore, the light intensity change can be obtained by experimentally measuring a standard substance with known absorbance, and then the equivalent absorption distance L can be obtained by reverse deduction.

[0014] Furthermore, each reflective ring is made of metal coated with a high-reflectivity film to minimize energy loss during light reflection. By optimizing the distribution of the reflective rings, the light beam emitted by the LED light source is precisely converged at the detector.

[0015] Beneficial Effects: The device designed in this invention conveniently and accurately measures light intensity by simply placing detectors symmetrically with the light source (with respect to the reflective panel). This not only solves the problem of light collimation during absorbance measurement, but also addresses challenges such as the parallelism and convergence of LED light sources. By providing flow channels on either side or one side of the reflective panel, measurements at two different optical path lengths can be achieved, expanding the measurement range. The entire device has a simple structure and is therefore highly user-friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention.

[0017] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. DETAILED DESCRIPTION

[0018] Example 1:

[0019] The device for measuring the absorbance of an LED light source includes an LED light source 1, an absorbance flow cell 2, and a detector 3. The absorbance flow cell 2 includes a reflective panel 4, a bottom panel 5, an upper panel 6, and a side panel 10. The bottom panel 5, the upper panel 6, and the side panel 10 form the absorbance flow cell. The reflective panel 4 is located within the absorbance flow cell and is arranged parallel to the bottom panel 5 and the upper panel 6. The reflective panel 4 has multiple reflective rings 9 nested within it. The reflective panel 4 also includes a flow cell inlet 7 and a flow cell outlet 8, which are respectively arranged on opposite side panels. The LED light source 1 and the detector 3 are symmetrically arranged above and below the reflective panel 4.

[0020] The divergence angle of the LED light source 1 is 20°, and the wavelength is 260 nm.

[0021] The absorbance flow cell 2 is made of highly transparent quartz glass.

[0022] The detector 3 is a photoelectric detector.

[0023] The LED light source 1 and the detector 3 are placed symmetrically about the reflective panel 4 .

[0024] The test liquid in the circulation pool passes through the space on one side between the reflective panel 4 and the bottom panel 5 , which corresponds to a vertical light absorption distance of 0.5 d.

[0025] Among them, the absorbance change is obtained by experimental measurement using a standard substance with known absorbance (potassium hydrogen phthalate, COD concentration is 100 mg / L), and then the equivalent absorption distance L is obtained by reverse deduction through the Lambert-Beer law.

[0026] Each reflective ring 9 is made of metal coated with a high reflectivity film layer, and the distribution of the reflective rings decreases in a gradient as the radius increases.

[0027] Example 2:

[0028] The structure of this embodiment is similar to that of embodiment 1, except that the divergence angle of the LED light source 1 is 120°. Through the following theoretical analysis, it can be obtained that the equivalent light absorption distance L=4d / 3.

[0029] The present invention also provides a method for testing the adaptability of different LED light sources. For LED light sources with different divergence angles, the vertical distance d between the bottom panel 5 and the upper panel 6 is adjusted, and the equivalent absorption distance L of light absorption is calculated using a theoretical formula, and then compared with the actual measured value for verification.

[0030] Further, theoretical calculation, the calculation formula of the equivalent absorption distance L is: Where θm is half of the maximum divergence angle of the LED.

[0031] Furthermore, the theoretical calculation derivation process is as follows:

[0032]

[0033] in The optical path length of light at angle θ; I(θ) = I0cos(θ): The light intensity distribution of the LED light source at angle θ under the Lambertian model; sin(θ)dθ: The area weight of the angle element in spherical coordinates. In the derivation process, the denominator integration process needs to use the variable substitution method. Let u = cos(θ), and the calculation can be obtained

[0034] The experimental verification was carried out by injecting a standard absorbance sample (such as a cobalt nitrate solution with known absorbance) into the absorbance flow cell 2, measuring the light intensity change value through the detector 3, and inferring the L value according to the Lambert-Beer law to verify the accuracy of the calculation formula.

[0035] Example 3:

[0036] The present invention also provides a method for measuring absorbance of liquid samples: methyl orange solutions of varying concentrations are selected as test samples, and absorbance measurements are performed using an LED light source with a divergence angle of 60° and a vertical distance d of 10 mm. The experimental steps are as follows:

[0037] 1. Inject the solution to be tested into the absorbance flow cell 2 in sequence, inject through the inlet 7 and discharge through the outlet 8.

[0038] 2. Start the device and record the light intensity signal of detector 3.

[0039] 3. Calculate the absorbance of the solution based on the Lambert-Beer law and the calculated equivalent absorption distance.

[0040] Through the above embodiments, the LED light source absorbance measurement device of the present invention has verified its high efficiency, low cost and high precision, and has wide application potential.

Claims

1. A device for measuring the absorbance of an LED light source, characterized in that: It includes an LED light source, an absorbance flow cell and a detector, wherein the absorbance flow cell includes a reflective panel, a bottom panel, an upper panel and a side panel, and the bottom panel, the upper panel and the side panel enclose the absorbance flow cell. The reflective panel is located in the absorbance flow cell and is arranged parallel to the bottom panel and the upper panel. Multiple reflective rings are nested inside the reflective panel, and the reflective panel also includes a flow cell inlet and a flow cell outlet. The flow cell inlet and the flow cell outlet are respectively arranged on opposite side panels, wherein the LED light source and the detector are placed symmetrically about the reflective panel.

2. The device for measuring the absorbance of an LED light source according to claim 1, wherein: The divergence angle of the LED light source ranges from 20° to 120°.

3. The device for measuring the absorbance of an LED light source according to claim 1, wherein: The absorbance flow cell is made of highly transparent quartz glass.

4. The device for measuring the absorbance of an LED light source according to claim 1, wherein: The detector is a photoelectric detector.

5. The device for measuring the absorbance of an LED light source according to claim 1, wherein: Each reflective ring is made of metal coated with a high-reflectivity film to ensure that the light beam emitted by the LED light source finally converges at the detector.

Images