CN-115524316-B - Method and mechanism for removing interference of excited fluorescent background signal by rotating polarization modulation

CN115524316BCN 115524316 BCN115524316 BCN 115524316BCN-115524316-B

Abstract

The invention relates to a method and a mechanism for removing interference of an excited fluorescence background signal by rotating polarization modulation, wherein laser is automatically incident, preprocessed and emitted to a dichroic mirror, reflected and emitted to a detection sample, excited fluorescence of the detection sample is emitted to the dichroic mirror, the excited fluorescence of the detection sample is modulated with part of the reflected laser after being transmitted to obtain excited fluorescence in a direct current state and modulated polarized laser, the excited fluorescence is obtained after being reprocessed to obtain output light, filtering is carried out, excited fluorescence information is reserved, background signal interference is removed, a preprocessing unit is arranged in cooperation with a laser incident channel, the dichroic mirror is arranged at the tail end of the laser incident channel, a rotating mechanism is arranged in cooperation with laser, a sample position is arranged in a sample optical detection channel at the reflecting light side of the dichroic mirror, and a modulating unit, a reprocessing unit and a signal processing system are sequentially arranged in a fluorescence optical detection channel at the transmitting light side of the dichroic mirror. The invention can be effectively distinguished by the filter, the linear polaroid can be installed at any angle, and even if the phase of the reflected background laser is changed, the phase can be eliminated by the filtering method.

Inventors

JIANG KAI
ZHANG TAO
TANG YAWEI

Assignees

苏州和迈精密仪器有限公司

Dates

Publication Date: 20260505
Application Date: 20220925

Claims (10)

1.A method for removing interference of excited fluorescent background signals by rotating polarization modulation is characterized by comprising the following steps: S1, autorotation and incidence of laser according to preset frequency are carried out, and the incident laser is preprocessed; S2, the preprocessed laser is emitted to a dichroic mirror installed at a preset angle, and is reflected by the dichroic mirror and then emitted to a detection sample; S3, detecting the stimulated fluorescence of the sample, transmitting the stimulated fluorescence to the dichroic mirror, and modulating the stimulated fluorescence with part of the reflected laser to obtain the stimulated fluorescence in a direct current state and the modulated polarized laser rotating at the same frequency; S4, reprocessing the stimulated fluorescence and modulated polarized laser of the S3 to obtain output light; S5, filtering the output light, retaining stimulated fluorescence information and removing background signal interference.
2. The method for removing interference of excitation fluorescent background signals by rotating polarization modulation according to claim 1, wherein the method comprises the following steps: in S1, the preprocessing includes filtering the laser light.
3. A method for removing interference of excitation fluorescence background signal by rotating polarization modulation according to claim 1, wherein in S2, the dichroic mirror is arranged at 45 degrees, and the incident surface of the dichroic mirror faces the incident laser light and the detection sample.
4. A method for removing interference of excitation fluorescence background signals by rotary polarization modulation according to claim 3, wherein in S2, the dichroic mirror reflects laser light into a sample optical detection channel, a first lens is arranged in the sample optical detection channel, a sample position for placing a detection sample is arranged on the focal length of the first lens, and fluorescence is emitted after excitation light irradiation of the detection sample, and the fluorescence is excited and is emitted to the dichroic mirror along the sample optical detection channel.
5. The method for removing interference of excitation fluorescence background signals by rotary polarization modulation according to claim 3, wherein in S3, the linear polarizer is used for modulating the excited fluorescence and the reflected laser of the detection sample to obtain the excited fluorescence in a direct current state and the modulated polarized laser rotating at the same frequency.
6. The method of claim 1, wherein S4, reprocessing comprises filtering and condensing the excited fluorescence and modulated polarized laser light in the DC state.
7. The method for removing interference of excitation fluorescent background signals by rotating polarization modulation according to claim 1, wherein in S5, the output light is subjected to signal acquisition by a photosensitive sensor and filtered by a filter, and a direct current signal is reserved.
8. A mechanism for removing interference of excited fluorescent background signals by adopting rotary polarization modulation according to the method of one of claims 1-7 is characterized by comprising a laser incidence channel matched with laser, a preprocessing unit matched with the laser incidence channel, a dichroic mirror arranged at the tail end of the laser incidence channel at a preset angle, a rotary mechanism matched with the laser; A sample optical detection channel is arranged on the reflected light side of the dichroic mirror, and a sample position for placing a detection sample is arranged on the sample optical detection channel; And a fluorescence optical detection channel is arranged on the transmission light side of the dichroic mirror, and a modulation unit, a reprocessing unit and a signal processing system are sequentially arranged on the fluorescence optical detection channel.
9. The mechanism for removing interference of excitation fluorescent background signals by rotating polarization modulation according to claim 8, wherein a rotation axis of the rotating mechanism is parallel to a laser incidence channel, the sample optical detection channel and the fluorescent optical detection channel are coaxial, and the laser incidence channel is perpendicular to the sample optical detection channel and the fluorescent optical detection channel.
10. The mechanism for removing interference from a background signal of excited fluorescence by rotating polarization modulation according to claim 8, wherein the dichroic mirror is disposed at 45℃with its incident surface facing the laser light incident channel and the sample optical detection channel.

Description

Method and mechanism for removing interference of excited fluorescent background signal by rotating polarization modulation Technical Field The invention relates to the technical field of optical elements, systems or instruments, in particular to a method and a mechanism for removing interference of excited fluorescent background signals by rotating polarization modulation. Background Fluorescent labels are widely applied to the fields of molecular and immunodetection, but the detection sensitivity of the fluorescent labels can not reach the same detection level of chemiluminescence, and the limiting factor for mainly limiting the improvement of the excitation fluorescence sensitivity is the background interference of an excitation light source. In general, the fluorescence signal emitted by the excitation light source is far higher than the self-luminescence fluorescence signal of chemiluminescence, and the advantage of self-luminescence fluorescence is mainly due to the fact that the background signal of the excitation light source is not interfered. If the detection sensitivity of the sensor is only improved under the background interference condition with the excitation light source, the interference signal is amplified in the same proportion, so that the key problem of improving the detection sensitivity of the excitation fluorescence is that the background interference introduced by the excitation light source is eliminated. In the prior art, for eliminating background interference, a light source modulation method is basically adopted, namely an excitation light sequence with specific frequency on-off is generated through an electric signal switch, and then fluorescent signals with the same frequency are collected, so that the fluorescent signals are distinguished from background ambient light, however, the largest interference source in the background signals is the light signal of an excitation light source, the light signal enters a detection sensor through a fluorescent filter, the interference of the light source cannot be eliminated through the modulation method because the excitation light and the fluorescent light are of the same frequency, the interference of the light source signal is generally eliminated through the narrow-band filtering of the fluorescent interference filter, and the detection sensitivity of the fluorescent signals is determined through the reflection light intensity of the excitation light source after the filter is determined due to the limited cut-off depth of the filter. Particularly, when the shift of the excitation light source wavelength and the fluorescence emission wavelength Stock is relatively small, the effect of the optical filter is poorer, and the detection sensitivity is difficult to improve. In order to solve the background interference of the excitation light source, two linear polarizers which are mutually perpendicular to each other and at 90 degrees are respectively arranged on an excitation light path and a fluorescence receiving light path for isolating the interference of the excitation light source, but the absolute perpendicular requirements on the polarizers in the scheme are high, and great difficulty is caused to processing and installation. In addition, the detection sample on the sample position is generally stored in a container made of ABS, PMMA, PC or other organic materials, and the materials all have birefringence, so that the polarization angle of the laser light source can be changed, and even if the linear polaroid of the excitation light path and the fluorescence receiving light path is completely vertical, the isolation effect cannot be realized. Disclosure of Invention The invention solves the problems in the prior art, and provides a method and a mechanism for removing interference of an excited fluorescent background signal by rotating polarization modulation, wherein the decoupling treatment of the linear polarization at a strict vertical angle is realized by rotating laser incidence and matching with a modulation scheme; because the excitation light source is in a rotating state, the excited fluorescence in a direct current state and the modulated polarized laser with the same rotating speed and the same frequency can be obtained through the modulation of the linear polaroid, and no matter the processing installation deviation or the polarization angle change caused by the birefringence interference of the sample container, only the phase of cosine wave is changed, but the frequency is not changed, so that the demodulated filtering isolation effect is not influenced; according to the invention, the modulated frequency polarized laser is filtered through the fixed frequency filter, so that the background interference of the excitation light source on the fluorescent signal is removed. The technical scheme adopted by the invention is that the method for removing interference of the excited fluorescent background signal by rotati