Optical configuration of a single-beam-based ultraviolet-visible spectrophotometer

Abstract

The utility model relates to optical technology field, concretely is a kind of optical configuration of ultraviolet visible spectrophotometer based on single light beam, compared with prior art, introduce mercury lamp as high-precision wavelength reference source in light source, for periodically calibrating wavelength to instrument, ensure that display wavelength is consistent with real value, improve the accuracy of measurement;Convenient switching of different light sources is realized through rotatable spherical surface light source mirror;Through plane mirror, optical path is realized 120 ° deflection, effectively reduce the straight-line propagation distance of optical path, make monochromator layout more regular, higher integration, to further reduce volume;Through the monitoring light path of proportional light mirror, proportional receiver composition, realize proportional receiver and sample receiver signal comparison, effectively suppress the baseline drift and noise enhancement of instrument, improve the stability, repeatability and signal-to-noise ratio of measurement.

Description

Technical Field

[0001] This utility model relates to the field of optical technology, specifically to an optical structure for a single-beam ultraviolet-visible spectrophotometer. Background Technology

[0002] The ultraviolet-visible spectrophotometer originates from the wave-particle duality of light and the principle of selective absorption of light by substances. Its core is based on the characteristic absorption of ultraviolet light (190-400 nm) and visible light (400-1100 nm) by valence electrons in molecules, developed in conjunction with the Lambert-Beer law. The ultraviolet-visible spectrophotometer generates a continuous spectrum through a light source, which is then separated into monochromatic light by a monochromator. After illuminating the sample, the transmitted light signal is captured by a detector and converted into absorbance, enabling qualitative and quantitative analysis of substances. The optical structure of the ultraviolet-visible spectrophotometer integrates technologies such as light propagation, spectrophotometry, and signal conversion, and it is widely used in material analysis in fields such as chemistry, biology, and the environment.

[0003] The optical system of a UV-Vis spectrophotometer encompasses the overall optical path design principles of the instrument. It can generally be divided into the light source optical path, the monochromator optical path, and the sample and receiver optical paths. The sample and receiver optical paths can be further categorized into single-beam and dual-beam types. For single-beam UV-Vis spectrophotometer optical systems, improving the system's optical energy utilization efficiency, reducing stray light levels, minimizing the overall size of the optical system, and pursuing measurement stability and accuracy have always been the goals pursued in the field of UV-Vis spectrophotometry.

[0004] Currently, monochromators suffer from drawbacks such as excessive size, inconvenience in replacing the light source, and non-adjustable light source mirror angle, which negatively impact the stability and accuracy of measurements.

[0005] Therefore, it is necessary to design an optical structure for a single-beam UV-Vis spectrophotometer to reduce the size of the monochromator, facilitate light source switching, and improve the stability and accuracy of the measurement. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an optical structure for a single-beam ultraviolet-visible spectrophotometer, so as to reduce the volume of the monochromator, facilitate the switching of the light source, and improve the stability and accuracy of the measurement.

[0007] To achieve the above objectives, this invention provides an optical structure for a single-beam ultraviolet-visible spectrophotometer, comprising a light source, a rotatable spherical light source mirror, an entrance slit, a plane mirror, an entrance collimating mirror, a grating, an exit collimating mirror, an exit slit, a semi-transparent mirror, a proportional condenser, a proportional receiver, a first condenser, a sample cell, a receiver condenser, and a sample receiver. The light source is positioned in the incident light path of the rotatable spherical light source mirror, and the exit light path of the rotatable spherical light source mirror sequentially includes an entrance slit and a plane mirror. An entrance collimator is provided in the exit light path, a grating is provided in the exit light path of the entrance collimator, an exit collimator is provided in the exit light path of the grating, an exit slit and a semi-transparent mirror are provided in sequence in the exit light path of the exit collimator, a condenser lens, a sample cell, a receiver condenser lens and a sample receiver are provided in sequence in the transmission light path of the semi-transparent mirror, and a proportional condenser lens and a proportional receiver are provided in sequence in the reflection light path of the semi-transparent mirror. The light source includes a tungsten lamp, a deuterium lamp and a mercury lamp. The positions of the tungsten lamp, deuterium lamp and mercury lamp are matched with the rotation angle of the rotatable spherical light source mirror.

[0008] The angle between the incident light path and the outgoing light path of the spherical light source mirror where the tungsten lamp or deuterium lamp is located is 20°, and the angle between the incident light path and the outgoing light path of the spherical light source mirror where the mercury lamp is located is 46°.

[0009] The spherical light source mirror is a plano-concave spherical mirror.

[0010] The light rays emitted from the plane rotating mirror to the collimating mirror, the light rays emitted from the collimating mirror to the grating, and the light rays emitted from the grating to the collimating mirror intersect in front of the collimating mirror and the collimating mirror.

[0011] The angle between the incident light path and the outgoing light path of the plane rotating mirror is 120°.

[0012] The distance between the exit collimator and the entrance slit is 99mm.

[0013] The distance between the grating and the exit collimator, and the distance between the grating and the entrance collimator, are 84.5 mm.

[0014] The inlet slit and outlet slit are located at the far ends of both sides of the grating.

[0015] Compared with existing technologies, this invention introduces a mercury lamp as a high-precision wavelength reference source into the light source for periodic wavelength calibration of the instrument, ensuring that the displayed wavelength is consistent with the true value and improving measurement accuracy. A rotatable spherical light source mirror enables convenient switching between different light sources. A planar rotating mirror achieves a 120° deflection of the optical path, effectively reducing the straight-line propagation distance of the light path, making the monochromator layout more regular and its integration higher, thereby further reducing the size. A monitoring optical path composed of a proportional optical mirror and a proportional receiver enables signal comparison between the proportional receiver and the sample receiver, effectively suppressing baseline drift and noise enhancement of the instrument, and improving measurement stability, repeatability, and signal-to-noise ratio. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0017] The present invention will now be further described with reference to the accompanying drawings.

[0018] See Figure 1 This invention relates to the optical structure of a single-beam ultraviolet-visible spectrophotometer, comprising a light source, a rotatable spherical light source mirror 4, an entrance slit, a plane rotating mirror, an entrance collimating mirror, a grating, an exit collimating mirror, an exit slit, a semi-transparent mirror, a proportional condenser, a proportional receiver, a condenser lens 1, a sample cell, a receiver condenser, and a sample receiver. The light source is positioned in the incident light path of the rotatable spherical light source mirror 4, and the exit light path of the rotatable spherical light source mirror 4 is sequentially provided with an entrance slit 5 and a plane rotating mirror 6. The plane rotating mirror 6 has an entrance collimating mirror 7 in its exit light path, a grating 8 in its exit light path, an exit collimating mirror 9 in its exit light path, an exit slit 10 and a semi-transparent mirror 11 in sequence in its exit light path, a condenser lens 14, a sample cell 15, a receiver condenser lens 16, and a sample receiver 17 in sequence in its transmission light path, and a proportional condenser lens 12 and a proportional receiver 13 in sequence in its reflection light path.

[0019] The light source includes a tungsten lamp 1, a deuterium lamp 2, and a mercury lamp 3. The positions of the tungsten lamp 1, deuterium lamp 2, and mercury lamp 3 are matched with the rotation angle of the rotatable spherical light source mirror 4. The rotatable spherical light source mirror 4 can be adjusted manually or electrically according to different light sources, thereby realizing convenient switching between different light sources and simplifying the assembly process of the light source.

[0020] When using tungsten lamp 1 or deuterium lamp 2 as the light source, the spherical light source mirror 4 rotates 10 degrees to the left or right along the normal. The angle between the incident light path and the outgoing light path of the spherical light source mirror 4 containing tungsten lamp 1 or deuterium lamp 2 is 20°, allowing the light emitted from tungsten lamp 1 or deuterium lamp 2 to directly enter the slit 5. When using mercury lamp 3 as the light source, the spherical light source mirror 4 rotates 23 degrees to the left along the normal. The angle between the incident light path and the outgoing light path of the spherical light source mirror 4 containing mercury lamp 3 is 46°, allowing the light emitted from mercury lamp 3 to directly enter the slit 5. The spherical light source mirror 4 can effectively converge and shape the light source, enhancing the utilization rate of the light source and the collimation of the outgoing light. This provides stable, sufficient, and spectrally broad incident light for subsequent detection, which is beneficial for obtaining higher optical energy to enter the slit 5, thus improving the overall optical energy utilization efficiency of the optical system.

[0021] When the mercury lamp 3 is used as a light source, it serves as a built-in high-precision wavelength reference source. By utilizing the authority and stability of the absolute wavelength values ​​of the characteristic emission spectral lines of the mercury lamp, the monochromator output wavelength of the instrument is periodically calibrated and verified, thereby eliminating system wavelength errors and ensuring that the spectral and quantitative measurement data have strict metrological traceability and repeatability.

[0022] The spherical light source mirror 4 is a plano-concave spherical mirror. The manufacturing process of spherical mirrors is more mature and easier to process. At the same time, it significantly simplifies the calibration process of the optical path and improves the adjustability of the system.

[0023] For tungsten lamp 1, where both the filament and slit are elongated rectangles, using a spherical mirror for focused imaging results in minimal filament aberration at the slit entrance, closely matching the slit's dimensions. This allows more light to be drawn into the slit, improving optical energy utilization. Other types of concave or curved mirrors produce greater filament aberrations than spherical mirrors, resulting in lower optical energy utilization.

[0024] The light rays emitted from the plane mirror 6 to the collimating mirror 7, the light rays emitted from the collimating mirror 7 to the grating 8, and the light rays emitted from the grating 8 to the collimating mirror 9 intersect in front of the collimating mirror 7 and the collimating mirror 9, which significantly improves the spatial arrangement efficiency of optical elements and thus greatly reduces the system volume.

[0025] The angle between the incident and exit light paths of the plane mirror 6 is 120°. After the light path enters the entrance slit 5, it is deflected by 120° by the plane mirror 6. This structure not only effectively compresses the volume of the monochromator but also makes the overall layout more compact and reasonable, thereby significantly improving the integration and space utilization efficiency of the optical path. The entrance slit 5 and exit slit 10 are located at the far ends of both sides of the grating 8, which helps to improve the system's signal-to-noise ratio.

[0026] The grating 8 is the core dispersive element, which achieves fine beam splitting based on the principle of diffraction; while the collimating lens 9 is responsible for focusing and collimating the split monochromatic light, ensuring that it is transmitted to the subsequent optical channel efficiently and stably, effectively improving the output quality and directional consistency of the monochromatic light.

[0027] The distances between the exit collimator 9 and the entrance slit 5, and between the exit collimator 9 and the exit slit 10, are 99 mm. The distances between the grating 8 and the exit collimator 9, and between the grating 8 and the entrance collimator 7, are 84.5 mm. The monochromator of the optical system has dimensions of 190 × 130 mm, making it more suitable for scenarios with high requirements for detection efficiency and miniaturization. At the same time, the simplified optical path layout reduces light scattering loss during transmission, greatly improving optical energy utilization. This optimized optical path layout provides a stable optical foundation for high-sensitivity detection.

[0028] In operation, this invention uses a tungsten lamp 1, a deuterium lamp 2, and a mercury lamp 3 as light sources. The light beam emitted from the light source is incident on a spherical light source mirror 4, which converges the light and guides it into an entry slit 5. After passing through the entry slit 5, the light beam is reflected by a plane rotating mirror 6, turned, and then incident on an entry collimating mirror 7. The collimated parallel beam then illuminates a grating 8 for beam splitting. The split beam is collected and focused by an exit collimating mirror 9, passes through an exit slit 10, and then incident on a semi-transparent mirror 11. The semi-transparent mirror 11 splits the light path into two beams. One beam passes through a condenser lens 14, a sample cell 15, and a receiver condenser lens 16 before being collected by a sample receiver 17. The other beam passes through a proportional condenser lens 12 before being collected by a proportional receiver 13. The proportional receiver 13 continuously collects a reference signal and synchronously compares it with the sample signal collected by the sample receiver 17. The comparison can also be performed by ratio calculation, thereby effectively suppressing baseline drift and noise enhancement.

[0029] This invention introduces a mercury lamp as a high-precision wavelength reference source into the light source for periodic wavelength calibration of the instrument, ensuring that the displayed wavelength matches the true value and improving measurement accuracy. A rotatable spherical light source mirror enables convenient switching between different light sources. A planar rotating mirror achieves a 120° deflection of the optical path, effectively reducing the straight-line propagation distance and making the monochromator layout more regular and integrated, thereby further reducing the size. A monitoring optical path composed of a proportional mirror and a proportional receiver enables comparison between the proportional receiver and the sample receiver, effectively suppressing baseline drift and noise enhancement, and improving measurement stability, repeatability, and signal-to-noise ratio.

Claims

1. An optical structure for a single-beam ultraviolet-visible spectrophotometer, comprising a light source, a rotatable spherical light source mirror, an entrance slit, a plane rotating mirror, an entrance collimating mirror, a grating, an exit collimating mirror, an exit slit, a semi-transparent mirror, a proportional condenser, a proportional receiver, a first condenser, a sample cell, a receiver condenser, and a sample receiver, characterized in that: The light source is set in the incident light path of the rotatable spherical light source mirror (4). The exit light path of the rotatable spherical light source mirror (4) is provided with an entrance slit (5) and a plane rotating mirror (6) in sequence. The exit light path of the plane rotating mirror (6) is provided with an entrance collimating mirror (7). The exit light path of the entrance collimating mirror (7) is provided with a grating (8). The exit light path of the grating (8) is provided with an exit collimating mirror (9). The exit light path of the exit collimating mirror (9) is provided with an exit slit (10) and a semi-transparent and semi-reflective mirror (11) in sequence. The semi-transparent and semi-reflective mirror (11) is provided with a condenser lens (14), a sample cell (15), a receiver condenser lens (16), and a sample receiver (17) in sequence on the transmission light path. The semi-transparent and semi-reflective mirror (11) is provided with a proportional condenser lens (12) and a proportional receiver (13) in sequence on the reflection light path. The light source includes a tungsten lamp (1), a deuterium lamp (2), and a mercury lamp (3). The positions of the tungsten lamp (1), the deuterium lamp (2), and the mercury lamp (3) are matched with the rotation angle of the rotatable spherical light source mirror (4).

2. The optical structure of a single-beam ultraviolet-visible spectrophotometer according to claim 1, characterized in that: The angle between the incident light path of the spherical light source mirror (4) where the tungsten lamp (1) or deuterium lamp (2) is located and the outgoing light path of the spherical light source mirror (4) is 20°, and the angle between the incident light path of the spherical light source mirror (4) where the mercury lamp (3) is located and the outgoing light path of the spherical light source mirror (4) is 46°.

3. The optical structure of a single-beam ultraviolet-visible spectrophotometer according to claim 1, characterized in that: The spherical light source mirror (4) is a plano-concave spherical mirror.

4. The optical structure of a single-beam ultraviolet-visible spectrophotometer according to claim 1, characterized in that: The light rays emitted from the plane rotating mirror (6) to the collimating mirror (7), the light rays emitted from the collimating mirror (7) to the grating (8), and the light rays emitted from the grating (8) to the collimating mirror (9) intersect in front of the collimating mirror (7) and the collimating mirror (9).

5. The optical structure of a single-beam ultraviolet-visible spectrophotometer according to claim 1, characterized in that: The angle between the incident light path and the outgoing light path of the plane rotating mirror (6) is 120°.

6. The optical structure of a single-beam ultraviolet-visible spectrophotometer according to claim 1, characterized in that: The distance between the exit collimator (9) and the entrance slit (5), and the distance between the exit collimator (9) and the exit slit (10) are 99 mm.

7. The optical structure of a single-beam ultraviolet-visible spectrophotometer according to claim 1, characterized in that: The distance between the grating (8) and the exit collimator (9) and the distance between the grating (8) and the entrance collimator (7) are 84.5 mm.

8. The optical structure of a single-beam-based ultraviolet-visible spectrophotometer according to claim 1, characterized in that: The inlet slit (5) and outlet slit (10) are located at the far ends of both sides of the grating (8).

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