Wavelength sensor based on fluorescent film

Abstract

The invention discloses a wavelength sensor based on a fluorescent film. The wavelength sensor is composed of the fluorescent film and a photoelectric detector. The fluorescent film is used for converting short-wave light into long-wave light, and the photoelectric detector is used for detecting incident light. The sensor is based on the characteristic that the photocurrent ratio of a detector with a fluorescent film and a detector without a fluorescent film is monotonically attenuated along with the increase of the wavelength of incident light, so that wavelength identification is realized. The sensor has the advantages of being easy to prepare, simple in structure, low in cost, convenient to operate, self-powered and the like, ultraviolet recognition is accurate, and weak light detection is sensitive. Meanwhile, by improving the light conversion performance of the fluorescent film, the precision and sensitivity of light recognition can be further improved.

Description

Technical Field

[0001] The present invention belongs to the field of photodetectors, and particularly relates to a wavelength sensor based on a fluorescent film. Background Art

[0002] In recent years, wavelength sensors, with their ability to qualitatively distinguish different light wavelengths, have important applications in many fields such as spectral analysis, color imaging, bionic eyes, optical communication, and security detection, showing broad development prospects and great research value. However, currently, whether it is a wavelength sensor realized with or without the assistance of a filter, or a wavelength sensor realized based on a vertical stacking structure or a charge collection narrowing mechanism, most wavelength sensors not only have problems such as cumbersome preparation processes, complex device structures, and high prices, but also, since their wavelength recognition range is usually limited to the visible light region and their responsivity to the ultraviolet band is relatively low, this greatly limits the further application of wavelength sensors in the field of ultraviolet detection, and ultraviolet detection is crucial for military and civilian fields such as ultraviolet communication, missile warning, environmental monitoring, and medical safety. Therefore, it is particularly crucial to propose a wavelength sensor that is easy to prepare, has a simple structure, low cost, and can effectively identify ultraviolet light. Summary of the Invention

[0003] Based on the problems existing in the above-mentioned prior art, the present invention provides a wavelength sensor based on a fluorescent film, which has the advantages of easy preparation, simple structure, convenient operation, low cost, precise and sensitive ultraviolet recognition.

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] A wavelength sensor based on a fluorescent film, which is composed of a fluorescent film and a photodetector;

[0006] When light is incident, since the fluorescent film can convert short-wavelength light into long-wavelength light, the light response of the detector with the fluorescent film is higher than that of the detector without the fluorescent film, and the light response difference increases as the incident light wavelength becomes smaller, resulting in the photocurrent ratio of the detector with the fluorescent film and the detector without the fluorescent film monotonically decaying as the incident light wavelength becomes larger. Thus, the wavelength of the incident light can be identified according to the photocurrent ratio.

[0007] Among them, the fluorescent film is a fluorescent material or a fluorescent composite material for short-wavelength to long-wavelength conversion, and the photodetector is a photovoltaic cell, a photoconductive cell, a photodiode, or an avalanche photodetector for incident light detection.

[0008] Among them, the working process of the sensor is as follows:

[0009] Place the detectors with fluorescent films and without fluorescent films under light of known wavelengths respectively, collect the photocurrents of the two detectors at the same wavelength and compare them. Obtain an empirical formula as a standard by fitting the photocurrent ratios at different wavelengths. Then place the two detectors under light of the wavelength to be measured respectively, collect the photocurrents and compare them. Finally, substitute into the standard empirical formula for calculation to obtain the wavelength value of the light to be measured.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. The wavelength sensor of the present invention provides a new method based on fluorescent films for optical recognition. This sensor is not only easy to fabricate, simple in structure, and low in cost, but also convenient to operate and self-powered.

[0012] 2. The optical recognition range of the wavelength sensor of the present invention covers the ultraviolet to visible light band. Moreover, as the wavelength of the light to be measured becomes smaller, its optical recognition accuracy is higher. At the same time, by improving the optical conversion performance of the fluorescent film, the photocurrent response difference between the detector with a fluorescent film and the detector without a fluorescent film can be increased, thereby further improving the optical recognition accuracy of the sensor and achieving higher-precision detection.

[0013] 3. The wavelength sensor of the present invention realizes optical recognition through a fluorescent film with high optical conversion performance and has excellent weak-light recognition sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure and operation of the wavelength sensor in Example 1.

[0015] Figure 2 It is a graph of the measured data and fitting results of the wavelength sensor in Example 1 under light of different wavelengths.

[0016] Figure 3 It is a schematic diagram of the structure and operation of the wavelength sensor in Example 2.

[0017] Figure 4 It is a schematic diagram of the structure and operation of the wavelength sensor in Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0018] The following further describes a wavelength sensor based on a fluorescent film according to the present invention in conjunction with specific embodiments and the drawings.

[0019] Example 1 As Figure 1As shown in the figure, a wavelength sensor consists of a fluorescent film and a photodetector. In this embodiment, the fluorescent film used is a perovskite quantum dot / polymer fluorescent composite prepared in the laboratory, the photodetector is a commercial silicon photovoltaic cell, and the light source is a commercial light-emitting diode. First, measure the photocurrents of detectors A and B with and without the fluorescent film under light of known wavelengths at zero bias, and compare the photocurrents at the same wavelength; then, fit the photocurrent ratios at different wavelengths to obtain a standard empirical formula, such as Figure 2 shown; finally, substitute the photocurrent ratio under the light of the wavelength to be measured into the formula for calculation to obtain the value of the wavelength to be measured, thereby realizing wavelength identification. It can be seen that the smaller the wavelength, the larger the photocurrent ratio, the higher the resolution of the sensor, and the more sensitive and accurate the wavelength identification.

[0020] Embodiment 2 As Figure 3 shown, a wavelength sensor consists of a fluorescent film, two photodetectors, and a light shield. It is an equivalent structure or device of the wavelength sensor described in Embodiment 1. Its working principle and process are basically the same as those of the Embodiment 1 sensor, and it is required that the optical power densities incident on the detectors with and without the fluorescent film are equal. The sensor in Embodiment 1 keeps the position of the detector unchanged during illumination, so as to ensure that the incident optical power densities with and without the fluorescent film are equal, while the sensor in this embodiment ensures that the optical power densities on both sides are equal by requiring the light to be incident from the middle of the parallel-arranged detectors with and without the fluorescent film.

[0021] Embodiment 3 As Figure 4 shown, a wavelength sensor consists of a fluorescent film, two photodetectors, and a 50:50 beam splitter. It is an equivalent structure or device of the wavelength sensor described in Embodiment 2. Its working principle and process are basically the same as those of the Embodiment 2 sensor, and it is also required that the optical power densities incident on the detectors with and without the fluorescent film are equal. Different from the sensor in Embodiment 2, the sensor in this embodiment ensures the equality of the incident optical power density through a beam splitter, with higher precision.

[0022] The specific embodiments of the present invention are elaborated in detail above, but the embodiments cited are not intended to limit the present invention. They are only used to understand the present invention and enable its implementation. Any equivalent replacement, modification, etc. made using the technical solution of the present invention shall fall within the scope of patent protection of the present invention.

Claims

1. A wavelength sensor based on a fluorescent film, characterized in that: The sensor is composed of a fluorescent film and a photodetector; When light is incident, since the fluorescent film can convert short-wave light into long-wave light, the light response of the detector with fluorescent film is higher than that of the detector without fluorescent film, and the light response difference increases as the wavelength of the incident light becomes smaller, resulting in the photocurrent ratio of the detector with fluorescent film and the detector without fluorescent film decaying monotonically as the wavelength of the incident light becomes larger. Therefore, the wavelength of the incident light can be identified based on the photocurrent ratio.

2. A wavelength sensor based on a fluorescent film according to claim 1, characterized in that: The fluorescent film is a fluorescent material or a fluorescent composite material used for converting short-wave light into long-wave light, and the photodetector is a photocell, a photoconductor, a photodiode or an avalanche photodetector used for incident light detection.

3. The wavelength sensor based on fluorescent film according to claim 1, characterized in that: The working process of the sensor is: The detectors with fluorescent film and without fluorescent film are placed under light of known wavelength respectively, the photocurrents of the two detectors at the same wavelength are collected and compared, and an empirical formula is obtained by fitting the photocurrent ratio at different wavelengths as a standard. Then the two detectors are placed under light of the wavelength to be measured respectively, the photocurrents are collected and compared, and finally the standard empirical formula is substituted for calculation to obtain the wavelength value of the light to be measured.

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