A full-wavelength microplate reader light path system based on a multi-spectral LED light mixing module

Abstract

The application provides a full-wavelength enzyme marker light path system based on a multi-spectrum LED light mixing module, relates to the technical field of biochemical detection equipment, and outputs wide-spectrum light through a multi-spectrum LED array, forms small-divergence-angle parallel light after beam shaping of a collimating lens array, and then forms uniform parallel wide-spectrum light beams after light condensation of a Fresnel lens, beam homogenization of an optical integrator and collimation of a collimating lens; after focusing and beam limiting of a beam shaping module, the light beams are incident to a light splitting module; the light beams are rotated and split through a concave diffraction grating to realize fiber output of 200-1000nm continuous monochromatic light; the monochromatic light output by the fiber is incident to a measurement module, is received by a detector after irradiating a sample, and finally the absorbance of the sample at a corresponding wavelength is calculated. The application replaces a traditional xenon lamp with multi-spectrum LED array light mixing, cooperates with optimized beam shaping, light splitting and measurement light paths, and fundamentally solves the problems of short service life, uneven energy, poor stability and large drift of the light source of the existing enzyme marker.

Description

Technical Field

[0001] This invention relates to the field of biochemical detection equipment technology, specifically to the optical path system of a full-wavelength enzyme-linked immunosorbent assay (ELISA) reader. Background Technology

[0002] Full-wavelength ELISA readers are core equipment in life sciences, biochemical assays, and high-throughput analysis, capable of continuous wavelength detection from 200-1000 nm, and have a wide range of applications. Currently, commercially available full-wavelength ELISA readers generally use xenon lamps as a broadband light source, which has insurmountable technical drawbacks in practical use: 1. Short lifespan and rapid decay of light source: Xenon lamps are gas discharge light sources, and their electrodes are prone to aging and ablation. The spectral output will irreversibly decay over time, requiring frequent replacement and resulting in high maintenance costs.

[0003] 2. Extremely uneven energy distribution across the entire spectrum: The output intensity of the xenon lamp varies greatly in the ultraviolet, visible, and near-infrared ranges, resulting in inconsistent detection sensitivity at different wavelengths, which significantly increases signal nonlinearity error and correction difficulty.

[0004] 3. Poor light intensity temporal stability: Affected by arc drift, temperature drift, and drive fluctuations, the output light intensity of the xenon lamp is subject to instantaneous disturbances and long-term baseline drift, making it difficult to meet the requirements of low noise and high repeatability for high-precision biochemical detection.

[0005] 4. Slow startup, high power consumption, and high heat generation: Not suitable for portable, low-power, and long-term continuous monitoring scenarios.

[0006] Multispectral LED arrays have advantages such as long lifespan, configurable spectrum, and high stability, making them an ideal alternative to xenon lamps. However, existing technologies lack a systematic, integrated, and engineerable complete optical path solution for integrating multispectral LED mixing into a full-wavelength microplate reader, making it impossible to achieve continuous wavelength, high uniformity, and high stability detection output in the 200-1000nm range. Summary of the Invention

[0007] This invention proposes a full-wavelength microplate reader optical path system based on a multispectral LED mixing module. It replaces the traditional xenon lamp with a multispectral LED array mixing system, and with optimized beam shaping, spectral splitting and measurement optical paths, it fundamentally solves the problems of short light source life, uneven energy, poor stability and large drift in existing microplate readers.

[0008] The present invention adopts the following technical solution: An optical path system for a full-wavelength microplate reader based on a multispectral LED mixing module includes: an M1 multispectral LED mixing module, an M2 beam shaping module, an M3 beam splitting coupling module, and an M4 measurement module. The output of the M1 multispectral LED mixing module is connected to the input of the M2 beam shaping module, the output of the M2 beam shaping module is connected to the input of the M3 beam splitting coupling module, and the output of the M3 beam splitting coupling module is connected to the input of the M4 measurement module. The M1 multispectral LED mixing module includes a multispectral LED array, a collimating lens array, a Fresnel lens, an optical integrator, and a first collimating lens arranged sequentially. The multispectral LED array is composed of multiple LED chips with different center wavelengths and different spectral bandwidths, forming a continuous broadband light source. The collimating lens array is used in conjunction with the multispectral LED array. Each collimating lens is used to collimate a single LED to reduce the divergence angle of the light source, improve the light energy utilization rate, and form quasi-parallel light with a small divergence angle. The Fresnel lens is used to converge the quasi-parallel light after passing through the collimating lens array, forming a Gaussian-distributed irradiation spot at the front end of the optical integrator. The optical integrator consists of a first microlens array and a second microlens array. Each microlens in the first microlens array is used to segment the converged Gaussian-distributed irradiation spot and image it onto the second microlens array. Each microlens in the second microlens array superimposes the image segmented by the first microlens array, thereby achieving the effect of uniform light. The first collimating lens is used to convert the homogenized beam into a collimated broadband beam, which then enters the subsequent beam shaping module. The M2 beam shaping module includes concave mirrors and a first slit aperture arranged sequentially. The concave mirror is used to reflect and focus a directly incident broadband beam, improving the compactness of the optical path system. The first slit aperture is used to shape and limit the beam after reflection and focusing, so as to filter out stray light, improve beam directionality, and form the incident beam of the subsequent beam splitting module. The M3 beam splitting coupling module includes a concave grating, a second slit stop, and an optical fiber arranged sequentially. The concave grating is used to decompose the shaped incident broadband beam into a spectrum arranged by wavelength, and simultaneously focus the light of each wavelength to its corresponding image point. The second slit aperture is used to select light of a specific wavelength from the focused spectral image and limit the spectral bandwidth to ensure the spectral resolution of the full-wavelength microplate reader; The incident end face of the optical fiber is closely fitted to the light-emitting side of the second slit aperture, so that the monochromatic light beam selected by the second slit aperture is directly coupled into the optical fiber. The light beam is transmitted in the optical fiber in the form of total internal reflection, and after low-loss transmission, it is coupled out from the output end face of the optical fiber and enters the measurement optical path. The M4 measurement module includes a first focusing lens, a sample cell, a second collimating lens, a second focusing lens, and a photodetector arranged in sequence. The first focusing lens is used to focus the monochromatic beam coupled from the optical fiber into the sample cell, where it interacts with the sample to be tested in the sample cell through absorption. The second collimating lens is used to reshape the beam passing through the sample cell to ensure that the beam directionality meets the subsequent focusing requirements. The second focusing lens is used to converge the light beam shaped by the second collimating lens onto the photosensitive surface of the photodetector. After photoelectric conversion and data processing, the absorbance of the sample at the current wavelength is calculated.

[0009] Preferably, the multispectral LED array uses a combination of ultraviolet LEDs, deep ultraviolet LEDs, visible LEDs, and near-infrared LEDs, with a bandwidth covering the entire spectral range of 200-1000nm. By adjusting the number and spatial arrangement of LEDs in each band, the total irradiance and spectral distribution of the light source can be flexibly controlled, thereby achieving on-demand customization of energy and spectral shape within the 200-1000nm wide spectral band.

[0010] Preferably, the collimating lens array uses aspherical lenses, and the divergence angle is controlled within ±5°.

[0011] Preferably, the first microlens array in the optical integrator is located at the focal plane of the Fresnel lens, and the second microlens array is located at the focal plane of the first collimating lens.

[0012] Preferably, the first slit aperture is located at the focal plane of the concave mirror.

[0013] Preferably, the second slit stop is located at the spectral image plane of the concave grating.

[0014] Preferably, the concave grating is mounted on a precision rotating mechanism, which is driven by a motor to rotate around a specific axis. When the rotation angle of the concave grating changes, the center wavelength focused at the second slit aperture changes synchronously. By controlling the rotation angle of the motor, continuous tuning and scanning of the output wavelength can be achieved.

[0015] Preferably, the photodetector is located at the focal plane of the second focusing lens and is selected as an ultraviolet-enhanced silicon photodiode.

[0016] Preferably, in the M2 beam shaping module, an array of filters is added in front of the first slit stop to filter out higher-order diffraction spectral interference generated during beam splitting by the concave grating in the subsequent M3 beam splitting coupling module. By introducing a long-pass or band-pass filter array with a suitable cutoff wavelength in front of the slit, non-target order spectral components can be effectively attenuated, order overlap interference can be suppressed, and the monochromatic light output through the second slit stop can be ensured to have high spectral purity.

[0017] The beneficial effects of this invention are: (1) The lifespan of the light source is greatly improved, and there is no significant attenuation after long-term use: Semiconductor LED devices are used, which have a long lifespan, no electrode aging problem, stable spectral output, and greatly reduce equipment maintenance costs; (2) The energy is more balanced across the entire wavelength, and the detection consistency is better: By reasonably selecting and combining multi-band LEDs, the output spectrum in the 200-1000nm range can be made smoother, thereby reducing the energy difference between different wavelengths and reducing nonlinear errors; (3) The light intensity time stability is high and the baseline drift is small: LEDs can be driven by constant current, and there is no arc drift. The output light noise is low, and the instantaneous and long-term stability is significantly better than that of xenon lamps, meeting the requirements of high-precision absorbance detection; (4) The system structure is simple and the optical efficiency is high: the Fresnel lens, optical integrator, concave grating and other components are used to form a compact optical path, with fewer components, lower assembly and adjustment difficulty, and high system reliability; (5) Low power consumption, low heat generation and fast response: no preheating is required, and it can be lit instantly, which is suitable for portable, continuous and high-throughput detection scenarios; (6) Precise wavelength adjustment: the wavelength of 200-1000nm can be continuously adjusted by rotating the concave grating, which is compatible with traditional full-wavelength microplate readers. Attached Figure Description

[0018] Figure 1 This is a block diagram of the overall structure of the optical path system of the present invention; Figure 2 This is a schematic diagram of the optical structure of the M1 multispectral LED mixing module of the present invention; Figure 3 This is a schematic diagram of the optical structure of the M2 beam shaping module of the present invention; Figure 4 This is a schematic diagram of the optical structure of the M3 beam splitting coupling module of the present invention; Figure 5 This is a schematic diagram of the optical structure of the M4 measurement module of the present invention.

[0019] In the figure: 101-Multispectral LED array, 102-Collimating lens array, 103-Fresnel lens, 104-Optical integrator, 105-First collimating lens, 1041-First microlens array, 1042-Second microlens array; 201 - Concave mirror; 202 - First slit aperture; 301 - Concave grating, 302 - Second slit stop, 303 - Optical fiber; 401 - First focusing lens, 402 - Sample cell, 403 - Second collimating lens, 404 - Second focusing lens, 405 - Photodetector. Detailed Implementation

[0020] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings: Example 1: As Figures 1-5 As shown, a full-wavelength microplate reader optical path system based on a multispectral LED mixing module includes an M1 multispectral LED mixing module, an M2 beam shaping module, an M3 beam splitting coupling module, and an M4 measurement module, which are connected in sequence.

[0021] In the M1 multispectral LED mixing module, the multispectral LED array 101 is composed of LED chips with center wavelengths of 220nm, 254nm, 275nm, 297nm, 310nm, 340nm, 385nm, 430nm, 485nm, 520nm, 550nm, 590nm, 620nm, 680nm, 730nm, 760nm, 810nm, 850nm, 940nm, and 960nm. The number of LED chips in each band is configured according to the energy balance requirements, with the ultraviolet band accounting for 50%, the visible light band accounting for 20%, and the near-infrared band accounting for 30%.

[0022] The collimating lens array 102 uses aspherical lenses, which correspond one-to-one with each LED chip in the multispectral LED array 101, collimating the light output by each LED into quasi-parallel light with a divergence angle of ±4°.

[0023] The Fresnel lens 103 converges the light processed by the collimating lens array 102 to form a Gaussian distributed light spot at the front end of the optical integrator 104.

[0024] The first microlens array 1041 of the optical integrator 104 is located at the focal plane of the Fresnel lens 103, and the second microlens array 1042 is located at the focal plane of the first collimating lens 105. The focal length of a single lens in the first microlens array 1041 is 5mm, and the focal length of a single lens in the second microlens array 1042 is 8mm. By dividing and superimposing the light spots, uniform light is achieved, and a uniform broadband beam is output.

[0025] The first collimating lens 105 converts the homogenized beam into a collimated, uniform broadband beam and outputs it to the M2 beam shaping module.

[0026] In the M2 beam shaping module, the concave reflector 201 has a radius of curvature of 100mm and reflects and focuses the collimated broadband beam output by M1; the first slit stop 202 is located at the focal plane of the concave reflector 201, and the slit width is 0.2mm, which limits and shapes the focused beam and filters out stray light.

[0027] In this embodiment, a filter array is added in front of the first slit aperture 202. The filter array consists of two long-pass filters and one uncoated quartz glass plate. The cutoff wavelengths of the two long-pass filters are 350nm and 650nm, respectively, effectively filtering out the interference of higher-order diffraction spectra generated by the concave grating 301. The uncoated quartz glass plate is used for optical path matching to ensure that the optical path lengths before and after the switching element are consistent, avoiding the introduction of additional optical errors. The above three optical elements are uniformly mounted on an electric guide rail, which can automatically switch according to the target screening wavelength of the concave grating. The specific matching rules are as follows: when the target screening wavelength is greater than or equal to 200nm and less than 370nm, the quartz glass plate is selected; when the target screening wavelength is greater than or equal to 370nm and less than 650nm, a long-pass filter with a cutoff wavelength of 350nm is used; when the target screening wavelength is greater than or equal to 650nm and less than 1000nm, a long-pass filter with a cutoff wavelength of 600nm is switched to use. This structure can both suppress higher-order diffraction spectral interference in segments and maintain the consistency and stability of the system's optical path.

[0028] In the M3 beam splitting coupling module, the concave grating 301 has 1200 lines / mm and is mounted on a precision rotating mechanism. It is driven to rotate by a stepper motor, with a rotation angle range of 0°-60°. The second slit stop 302 is located on the spectral image plane of the concave grating 301, with a slit width of 0.05mm, to filter monochromatic light of a specific wavelength. The fiber optic cable 303 has a core diameter of 100μm, and its incident end face is attached to the light-emitting side of the second slit stop 302 to achieve low-loss light transmission.

[0029] In the M4 measurement module, the first focusing lens 401 has a focal length of 20mm, which focuses the monochromatic light output from the fiber optic 303 into the sample cell 402; the second collimating lens 403 has a focal length of 25mm, which performs secondary shaping on the beam passing through the sample cell 402; the second focusing lens 404 has a focal length of 20mm, which converges the shaped beam onto the photosensitive surface of the photodetector 405; the photodetector 405 is an ultraviolet-enhanced silicon photodiode with a response wavelength range of 190-1100nm, located at the focal plane of the second focusing lens 404, which converts the optical signal into an electrical signal and calculates the sample absorbance.

[0030] The working principle of the optical path system in this embodiment: The multispectral LED array 101 outputs broadband light, which is collimated by the collimating lens array 102, converged by the Fresnel lens 103, enters the optical integrator 104 to achieve uniform light, and is then converted into a collimated uniform broadband beam by the first collimating lens 105. The beam enters the M2 beam shaping module, is reflected and focused by the concave mirror 201, and then passes through the first slit aperture 202 for beam limiting and shaping to filter out stray light; The shaped beam enters the M3 beam splitting coupling module, where the concave grating 301 rotates and splits the beam into monochromatic light. After being filtered by the second slit aperture 302, the light is transmitted to the M4 measurement module via the optical fiber 303. Monochromatic light is focused by the first focusing lens 401 onto the sample cell 402 to interact with the sample. After being shaped again by the second collimating lens 403 and converged by the second focusing lens 404, the light signal is received by the photodetector 405, and finally the absorbance of the sample at the corresponding wavelength is calculated.

[0031] Tests have shown that the optical path system of this embodiment has a light source lifespan of over 50,000 hours, a light intensity baseline drift of ≤0.001 Abs / h, and a detection energy deviation of ≤10% for each wavelength from 200 to 1000 nm, fully meeting the requirements for high-precision full-wavelength microplate readers. Example

[0032] The difference between this embodiment and Embodiment 1 is that the band configuration and quantity ratio of the multispectral LED array 101 are adjusted, with the ultraviolet band LED chips accounting for 20%, the visible light band accounting for 40%, and the near-infrared band accounting for 40%, to adapt to the spectral requirements of specific biochemical detection scenarios. The slit width of the first slit stop 202 is 0.1 mm, and the slit width of the second slit stop 302 is 0.02 mm, further optimizing the stray light filtering effect.

[0033] The remaining structure and working principle are the same as in Example 1, which can achieve higher precision biochemical detection and is suitable for trace sample and high-precision analysis scenarios.

[0034] Industrial applicability of the invention: The optical path system of this invention can be applied to the production and manufacturing of full-wavelength ELISA readers. Through standardized modular design, it is easy to mass-produce and assemble. It can be adapted to full-wavelength ELISA readers in multiple fields such as medical testing, food testing, environmental monitoring, and biomedicine, and has good industrial promotion value and application prospects.

[0035] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A full-wavelength microplate reader optical path system based on a multispectral LED mixing module, characterized in that, include: M1 Multispectral LED Mixing Module, M2 Beam Shaping Module, M3 Beam Splitting Coupler Module, and M4 Measurement Module; The output of the M1 multispectral LED mixing module is connected to the input of the M2 beam shaping module, the output of the M2 beam shaping module is connected to the input of the M3 beam splitting coupling module, and the output of the M3 beam splitting coupling module is connected to the input of the M4 measurement module. The M1 multispectral LED mixing module includes a multispectral LED array, a collimating lens array, a Fresnel lens, an optical integrator, and a first collimating lens arranged sequentially. The multispectral LED array is composed of multiple LED chips with different center wavelengths and different spectral bandwidths, forming a continuous broadband light source. The collimating lens array is used in conjunction with the multispectral LED array. Each collimating lens is used to collimate a single LED, forming quasi-parallel light with a small divergence angle. The Fresnel lens is used to converge the quasi-parallel light after passing through the collimating lens array, forming a Gaussian-distributed irradiation spot at the front end of the optical integrator. The optical integrator consists of a first microlens array and a second microlens array. Each microlens in the first microlens array is used to segment the converged Gaussian-distributed irradiation spot and image it onto the second microlens array. Each microlens in the second microlens array superimposes the image segmented by the first microlens array, thereby achieving the effect of uniform light. The first collimating lens is used to convert the homogenized beam into a collimated broadband beam, which then enters the subsequent beam shaping module. The M2 beam shaping module includes concave mirrors and a first slit aperture arranged sequentially. The concave mirror is used to reflect and focus a directly incident broadband beam of light. The first slit aperture is used to shape and limit the beam after reflection and focusing, forming the incident beam of the subsequent beam splitting module; The M3 beam splitting coupling module includes a concave grating, a second slit stop, and an optical fiber arranged sequentially. The concave grating is used to decompose the shaped incident broadband beam into a spectrum arranged by wavelength, and simultaneously focus the light of each wavelength to its corresponding image point. The second slit stop is used to select light of a specific wavelength from the focused spectral image and limit the spectral bandwidth; The incident end face of the optical fiber is closely fitted to the light-emitting side of the second slit aperture, so that the monochromatic light beam selected by the second slit aperture is directly coupled into the optical fiber. The light beam is transmitted in the optical fiber in the form of total internal reflection, and after low-loss transmission, it is coupled out from the output end face of the optical fiber and enters the measurement optical path. The M4 measurement module includes a first focusing lens, a sample cell, a second collimating lens, a second focusing lens, and a photodetector arranged in sequence. The first focusing lens is used to focus the monochromatic beam coupled from the optical fiber into the sample cell, where it interacts with the sample to be tested in the sample cell through absorption. The second collimating lens is used to reshape the light beam passing through the sample cell. The second focusing lens is used to converge the light beam shaped by the second collimating lens onto the photosensitive surface of the photodetector. After photoelectric conversion and data processing, the absorbance of the sample at the current wavelength is calculated.

2. The optical path system of a full-wavelength microplate reader based on a multispectral LED mixing module according to claim 1, characterized in that, The multispectral LED array uses a combination of ultraviolet LEDs, deep ultraviolet LEDs, visible LEDs, and near-infrared LEDs, with a bandwidth covering the full spectrum range of 200-1000nm.

3. The optical path system of a full-wavelength microplate reader based on a multispectral LED mixing module according to claim 1, characterized in that, The collimating lens array uses aspherical lenses, and the divergence angle is controlled within ±5°.

4. The optical path system of a full-wavelength microplate reader based on a multispectral LED mixing module according to claim 1, characterized in that, The first microlens array in the optical integrator is located at the focal plane of the Fresnel lens, and the second microlens array is located at the focal plane of the first collimating lens.

5. The optical path system of a full-wavelength microplate reader based on a multispectral LED mixing module according to claim 1, characterized in that, The first slit aperture is located at the focal plane of the concave mirror.

6. The optical path system of a full-wavelength microplate reader based on a multispectral LED mixing module according to claim 1, characterized in that, The second slit stop is located at the spectral image plane of the concave grating.

7. The optical path system of a full-wavelength microplate reader based on a multispectral LED mixing module according to claim 1, characterized in that, The concave grating is mounted on a precision rotating mechanism and is driven by a motor to rotate around a specific axis. When the rotation angle of the concave grating changes, the center wavelength focused at the second slit aperture changes synchronously.

8. The optical path system of a full-wavelength microplate reader based on a multispectral LED mixing module according to claim 1, characterized in that, The photodetector is located at the focal plane of the second focusing lens and is selected as an ultraviolet-enhanced silicon photodiode.

9. The optical path system of a full-wavelength microplate reader based on a multispectral LED mixing module according to claim 1, characterized in that, In the M2 beam shaping module, a filter array is added in front of the first slit aperture.

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