A spectrophotometer optical system

Abstract

The application relates to a spectrophotometer optical system which comprises a first converging part, an incident part, a first concave mirror, a light splitting reflection grating, a second concave mirror, an exit slit, a second converging part, a detection cell, a converging lens and a detection part, the first converging part comprises a first lens and a second lens arranged in sequence along an optical path, the first concave mirror and the second concave mirror are off-axis concave mirrors, the second converging part comprises a first lens and a second lens, the light beam converged by the converging lens passes through the detection cell, passes through the converging lens after passing through the detection cell, and is finally detected by the detection part. The spectrophotometer optical system can realize material optical analysis or testing in a wide spectral range, and has the advantages of miniaturization and light weight.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of spectral analysis systems, in particular to a spectrophotometer optical system. BACKGROUND

[0002] A spectrophotometer is an important spectral analysis instrument, widely used in chemistry, biology, material science and printing, etc. Its main principle is that different substances have different absorption of specific wavelengths of light. By separating the composite wavelength light into single wavelength light through a monochromator, and measuring the absorption of the substance to the wavelength light, the composition or concentration of the substance can be calculated. In the printing field, the spectrophotometer not only improves the color quality and production efficiency of the printed matter, but also provides strong support for the sustainable development of the industry.

[0003] Traditional spectrophotometers usually achieve light separation and accurate wavelength measurement through optical systems. However, in the prior art, most spectrophotometers have limited spectral range, usually only covering the ultraviolet spectral region or the visible spectral region. In applications requiring simultaneous detection of ultraviolet, visible and near-infrared spectra, multiple devices or complex optical systems are often needed to complete the task. This approach not only increases the size and weight of the device, but also reduces the flexibility of the system, making it difficult to meet the needs of modern applications for miniaturization and portability. SUMMARY

[0004] To solve the above technical problems, the present application provides a spectrophotometer optical system, which can cover a wide spectral range of 200nm to 1100nm, i.e. simultaneously detecting wavelengths in the 200nm-380nm ultraviolet spectral region, 380nm-780nm visible spectral region and 780nm-1100nm near-infrared spectral region. Through optimized design, the system realizes miniaturization and light weight, greatly improving the flexibility of the spectrophotometer system.

[0005] This invention specifically relates to an optical system for a spectrophotometer, comprising: a first converging section (1) consisting of a first lens (11) and a second lens (12) arranged sequentially along the optical path; an entrance slit (2); a first concave mirror (3); a beam-splitting grating (4); a second concave mirror (5); an exit slit (6); a second converging section (7) including a third lens (71) and a fourth lens (72); a detection cell (8); a converging lens (9); and a detection section (10); the first lens (11), the second lens (12), the third lens (71), and the fourth lens (72) are all spherical mirrors, and the first concave mirror (3) and the second concave mirror (5) are off-axis concave mirrors; the incident light beam enters the converging section (1), passes through the first lens (11) and the second lens... (12) After converging sequentially, the beam is reflected by the first concave mirror (3) into a parallel beam through the path defined by the entrance slit (2). The direction of the parallel beam intersects with the direction of the incident beam. The parallel beam is split and reflected by the beam splitting grating (4) to the second concave mirror (5). The beam is then reflected by the second concave mirror (5) to form a spectrum and projected onto the exiting part (6) for emission. A slit is provided on the exiting part. The converging lens group (7) includes a first lens and a second lens. The converged beam passes through the detection cell (8), then through the converging lens (9), and finally through the detection unit (10). The optical power of the spectrophotometer optical system is Φ, the optical power of the first converging part (1) is Φ1, and the optical power of the first lens is Φ. 11 The optical power of the second lens (12) is Φ 12 It satisfies the following relationship: 0.24≤Φ 11 / Φ≤0.29, 0.31≤Φ 12 / Φ≤0.35, 0.13≤Φ 11 +Φ 12 ≤0.2, 0.3≤Φ1 / Φ≤0.41, and the distance from the entrance slit (2) to the object surface of the first lens (11) is less than the distance from the entrance slit (2) to the first concave mirror (3).

[0006] Furthermore, the optical power of the second converging part (7) is Φ7, which satisfies the following relationship: 0.22≤Φ7 / Φ≤0.35.

[0007] Furthermore, the optical power Φ of the third lens (71) 71 The optical power Φ of the fourth lens (72) 72 Satisfying 0.01≤Φ 71 =Φ 72 ≤0.067.

[0008] Further, the first concave mirror has a curvature radius R1, an inclination angle θ1 and an eccentricity Y1, and satisfies the following relationships: -0.01≤R1≤-0.006, -13°≤θ1≤-9° and 6≤Y1≤10.

[0009] Further, the second concave mirror has a curvature radius R2, an inclination angle θ2 and an eccentricity Y2, and satisfies the following relationships: -0.02≤R2≤-0.005, -20°≤θ2≤-16° and 4≤Y2≤10.

[0010] Further, the spectroscopic reflection grating has a grating constant d and an inclination angle θ3, and satisfies the following relationships: 2μm≤d≤10μm and 14°≤θ3≤25°.

[0011] Further, the spectroscopic reflection grating (4) is a blazed grating, and has a blazed wavelength λ, and satisfies the following relationship: 450nm≤λ≤625nm.

[0012] Further, the detection unit (6) comprises a receiving plane for directly receiving the light signal, and the receiving plane has an inclination angle θ4, and satisfies the following relationship: 10°≤θ4≤15°.

[0013] Further, the converging lens (9) has an optical power Φ9, and satisfies the following relationships: 0.01≤Φ9≤0.074 and 0.1≤Φ9 / Φ≤0.23.

[0014] The spectrophotometer optical system has the advantages of miniaturization and light weight, greatly improves the flexibility of the spectrophotometer system, has excellent light splitting function, clear separation of different color lights at different object planes, similar size of a diffraction spot and an Airy disk, stable spectrum forming, can cover a wide spectral range of 200nm to 1100nm in detection, that is, simultaneously detects wavelengths in the ultraviolet spectral region of 200nm-380nm, the visible light spectral region of 380nm-780nm and the near-infrared spectral region of 780nm-1100nm, the MTF (Modulation Transfer Function) of the full field of view at a spatial frequency of 100lp / mm is greater than 0.2, and the overall length is less than 160mm. In addition, the detection light path of the present application adopts a single-beam light path without beam splitting throughout the whole process, and the light energy utilization rate is higher. In the detection of low-concentration or weakly-absorbing samples, the single beam may exhibit a better signal-to-noise ratio, and the simplified optical path makes the instrument smaller in size, suitable for rapid detection in laboratories or on-site with limited space.

[0015] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0017] Figure 1 A schematic diagram of a spectrophotometer optical system according to an embodiment of the present application is shown;

[0018] Figure 2 A schematic diagram of a corresponding diffraction spot of a spectrophotometer optical system according to an embodiment of the present application is shown;

[0019] Figure 3 A curve diagram of a corresponding modulation transfer function of a spectrophotometer optical system according to an embodiment of the present application is shown.

[0020] Reference signs: 1-first converging part, 11-first lens, 12-second lens, 2-incoming slit, 3-first concave mirror, 4-splitting reflection grating, 5-second concave mirror, 6-detection part, 7-second converging part, 71-third lens, 72-fourth lens, 8-detection cell, 9-converging lens, 10-detection part DETAILED DESCRIPTION

[0021] The present application is further described below in conjunction with the accompanying drawings: the described embodiments are only a part of the embodiments of the present application, and not all, the following embodiments are only to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0022] Before the embodiments of the present application are described in detail, the spectrophotometer optical system involved in the present application is first introduced. It needs to be declared that the unit of optical power in the present application is mm, the unit of curvature radius is mm, and the unit of eccentricity is mm.

[0023] In the embodiments disclosed in the present application, in the order of the optical path, the spectrophotometer optical system includes: a first converging part 1 composed of a first lens 11 and a second lens 12 arranged in sequence along the optical path, an incoming slit 2, a first concave mirror 3, a splitting reflection grating 4, a second concave mirror 5, an outgoing slit 6, a second converging part 7 including a third lens 71 and a fourth lens 72, a detection cell 8, and a converging lens 9 and a detection part 10.

[0024] The incident light beam enters the first converging part 1, is sequentially converged by the first lens 11 and the second lens 12, is reflected by the first concave mirror 3 as a parallel light beam after being limited by the path of the incident slit 2, the direction of the parallel light beam intersects with the direction of the incident light beam, the parallel light beam is reflected by the light splitting reflection grating 4 to the second concave mirror 5, is reflected by the second concave mirror 5 to form a spectrum and is projected on the exit slit 6 to exit, the exit light is converged by the second converging part 7, the converged light beam passes through the detection cell 8 and the converging lens 9, finally forms a spectrum and is projected on the detection part 10 to form an image.

[0025] The incident slit 2 is arranged on the converging side of the first converging part, is a slit intersecting with and perpendicular to the extension line of the first converging part, and is used for limiting the path of the incident light beam; the first concave mirror 3 is arranged towards the incident slit 2, the light splitting reflection grating 4 is arranged towards the first concave mirror 3, the second concave mirror 5 is arranged towards the light splitting reflection grating 4, and the exit slit 6 is arranged towards the second converging part 7 and is used for limiting the path of the exit light beam; the second converging part 7 is arranged on the path of the exit light and converges the exit light; the converged light beam passes through the detection cell 8, and the detection cell 8 has different absorption rates for different wavelengths of light.

[0026] Due to the design of multiple reflections and the reasonable arrangement of the optical parameters and the position parameters of each part, the optical distortion is effectively controlled, and the miniaturization and lightness of the spectrophotometer optical system are realized. For the first converging part, the second converging part and the incident slit 2 and the exit slit 6, the description about the “object side” “image side” or “incident side” “converging side” can be referred to the light ray in Figure 1 The above “towards” means “can be connected by the light path” but is not equal to “facing”. The spectrophotometer optical system can realize the function only by six optical units and one detector, and the structure has the advantages of miniaturization and lightness, greatly improving the flexibility of the spectrophotometer system.

[0027] In a preferred embodiment, as shown in Figure 1 The first lens 11, the second lens 12, the third lens 71 and the fourth lens 72 are all spherical mirrors, the two lens combinations of the present application as the first converging part and the second converging part can better bear the optical power, reduce the sensitivity of lens processing and help to eliminate aberration.

[0028] In a preferred embodiment, the first concave mirror 3 and the second concave mirror 5 are off-axis concave mirrors.

[0029] In a preferred embodiment, as shown in Figure 1As shown, the optical power of the spectrophotometer optical system is Φ, the optical power of the first converging part (1) is Φ1, the optical power of the first lens 11 is Φ 11 , the optical power of the second lens 12 is Φ 12 , which satisfies the following relationships: 0.24≤Φ 11 / Φ≤0.29, 0.31≤Φ 12 / Φ≤0.35, 0.13≤Φ 11 +Φ 12 ≤0.2, 0.3≤Φ1 / Φ≤0.41, and the distance from the incident slit 2 to the object surface of the first lens (11) is less than the distance from the incident slit (2) to the first concave mirror (3), which helps to ensure clear separation of different colors of light at different object surfaces, close size of the diffraction spot and the Airy disk, and stable spectrum formation in a wide spectral range of 200 nm to 1100 nm.

[0030] In some embodiments, as shown in Figure 1 , the central axes (or equivalent central axes) of the first concave mirror 3, the light splitting reflection grating 4, the second concave mirror 5 and the detection part 6 are all tilted relative to the incident optical axis. Referring to Figure 1 , the tilt angle θ of any component is defined in the plane shown in Figure 1 : the angle between the central axis and the extension line of the incident optical axis, and the counterclockwise direction is positive.

[0031] In a preferred embodiment, as shown in Figure 1 , the first concave mirror has a radius of curvature R1, a tilt angle θ1 and an eccentricity Y1, which satisfy the following relationships: -0.01≤R1≤-0.006, -13°≤θ1≤-9°, 6≤Y1≤10.

[0032] In a preferred embodiment, as shown in Figure 1 , the second concave mirror has a radius of curvature R2, a tilt angle θ2 and an eccentricity Y2, which satisfy the following relationships: -0.02≤R2≤-0.005, -20°≤θ2≤-16°, 4≤Y2≤10.

[0033] In a preferred embodiment, as shown in Figure 1 , the light splitting reflection grating has a grating constant d and a tilt angle θ4, which satisfy the following relationships: 2μm≤d≤10μm, 14°≤θ4≤25°.

[0034] In a preferred embodiment, as shown in Figure 1 , the light splitting reflection grating 4 is a blazed grating, and the blaze wavelength is λ, which satisfies the following relationship: 450 nm≤λ≤625 nm.

[0035] In a preferred embodiment, as shown in Figure 1As shown, the exit slit 6 includes a receiving plane for directly receiving optical signals. The tilt angle of the receiving plane is θ6, which satisfies the following relationship: 10°≤θ6≤15°.

[0036] In the embodiments disclosed in this invention, the overall length of the spectrophotometer optical system is less than 210 mm, the overall height is less than 90 mm, and the length of the first converging part is less than 60 mm.

[0037] In a preferred embodiment, the distance from the entrance slit 2 to the image plane of the second lens 12 is less than one-third of the distance from the entrance slit 2 to the first concave mirror 3.

[0038] In a preferred embodiment, the distance from the beam-splitting reflective grating 4 to the first concave reflective mirror 3 is D. 34 The distance from the beam-splitting reflection grating 4 to the second concave reflector 5 is D. 45 The following relationship is satisfied: D 34 <D 45 More preferably, the following relationship is satisfied: 0.6≤D 34 / D 45 ≤0.85.

[0039] In a preferred embodiment, the distance from the beam-splitting reflective grating 4 to the second concave reflector 5 is D. 45 The distance from the detection plane of the exit slit 6 to the second concave reflector 5 is D. 56 The following relationship is satisfied: 0.74≤D 45 / D 56 ≤0.92.

[0040] In a preferred embodiment, such as Figure 1 As shown, the optical power of the second converging part 7 is Φ7, which satisfies the following relationship: 0.22≤Φ7 / Φ≤0.35.

[0041] In a preferred embodiment, such as Figure 1 As shown, the optical power Φ of the third lens 71 71 Optical power Φ of the fourth lens 72 72 Satisfying 0.01≤Φ 71 =Φ 72 ≤0.067.

[0042] In a preferred embodiment, such as Figure 1 As shown, the optical power Φ9 of the converging lens 9 satisfies 0.01≤Φ9≤0.074 and 0.1≤Φ9 / Φ≤0.23.

[0043] The aforementioned distances and lengths are defined on the incident optical axis or in a direction parallel to it, while the height direction is defined on... Figure 1The plane shown is perpendicular to the direction of the length. The above arrangement helps the spectrophotometer optical system to keep the diffused spot of each color light concentrated.

[0044] The following provides a specific embodiment of the present application and its technical effects for auxiliary explanation:

[0045] Referring to Figure 2 , in the spectrophotometer optical system, the first converging part is composed of the first lens 11 and the second lens 12 along the incident light axis, the optical power Φ1 of the first lens 11 is 0.02, the optical power Φ2 of the second lens 12 is 0.015, and the sum of the two optical powers satisfies 0.02≤Φ1+Φ2≤0.05; the length (in the direction of the incident light axis) of the entire first converging part (including the first lens 11, the second lens 12, and the assembly for fixedly connecting the first lens 11 and the second lens 12) is 50 mm.

[0046] The first converging part is connected with the incident slit 2 by a light shielding assembly, the incident slit 2 intersects and is perpendicular to the extension line of the incident light axis, only the light rays converging through the first converging part can pass through, and the length of the slit is 5.5 mm and the width is 0.2 mm, so as to accommodate the light in the wavelength range of 200 nm-1100 nm to pass through after being converged by the first converging part.

[0047] The first concave mirror 3 improves the correction ability of the system to the off-axis aberration and increases the field of view of the system; the curvature radius is -0.005, the inclination angle is -13°, the eccentricity is 6.5, and the distance (in the direction of the incident light axis) from the curvature center of the first concave mirror 3 to the incident slit 2 is 62 mm.

[0048] The diffraction grating constant of the blaze diffraction grating as the diffraction reflection grating 4 is 3 μm, the inclination angle is 22°, the blaze wavelength is 500 nm, and the transverse distance (i.e. in the direction parallel to the incident light axis) from the curvature center of the first concave mirror 3 to the diffraction reflection grating 4 is 46 mm.

[0049] The second concave mirror 5 further improves the correction ability of the system to the off-axis aberration; the curvature radius is -0.004, the inclination angle is -13°, the eccentricity is 6, and the transverse distance from the curvature center of the second concave mirror 5 to the diffraction reflection grating 4 is 60 mm.

[0050] The inclination angle of the receiving plane of the exit slit 6 is 12°, and the transverse distance from the curvature center of the second concave mirror 5 to the receiving plane is 78 mm; the position and angle of the receiving screen can be controlled and adjusted through communication connection to correspond to different object planes.

[0051] The second converging part is composed of the third lens 71 and the second lens 72 along the exit light axis, the optical power Φ 71 of the third lens 71 is 0.05, and the optical power Φ72 0.05, the optical power satisfies 0.01≤Φ 71 =Φ 72 0.067; the length (in the direction of the incident optical axis) of the entire first converging part (including the third lens 71 and the second lens 72 and the assembly for fixedly connecting the first lens 11 and the second lens 12) is 30 mm.

[0052] The detection pool is passed through the converging light beam (8), and the detection pool has different absorption rates of light of different wavelengths. The detection pool serves as a core carrier for the interaction of light and samples, provides a sealed space for containing liquid, gas or solid samples, and avoids external pollution or volatilization.

[0053] The optical power Φ9 of the converging lens 9 is 0.06, the optical power satisfies 0.01≤Φ9≤0.074, and 0.1≤Φ9 / Φ≤0.23, which converges light of different wavelengths to facilitate detection by the detector.

[0054] The length (in the direction of the incident optical axis) of the part of the spectrophotometer optical system except the first converging part and the second converging part is 102 mm, and the height (in the direction perpendicular to the incident optical axis) is 75 mm; the overall length of the spectrophotometer optical system is about 210 mm, which obviously has the advantages of miniaturization and light weight, realizes wide spectral range (200 nm-1100 nm) application, well controls optical distortion, and greatly improves the flexibility and practicality of the system.

[0055] The imaging effect of the specific embodiment is shown in Figure 2 , Figure 3 The figure shows the corresponding diffraction spot of the spectrophotometer optical system in this embodiment: under different object surface inclination angles (-0.300°, 0.000°, 0.300°), the light spots of wavelengths 200 nm (ultraviolet), 425 nm (about blue light), 650 nm (about red light), 875 nm (near-infrared), and 1100 nm (near-infrared) are respectively imaged from top to bottom at the corresponding image planes (-9.754 mm, -6.241 mm, -2.746 mm). In the horizontal scale, the distribution of each light spot is relatively concentrated, and the diffraction spot is nearly circular as a whole. Under different angles, the position of the diffraction spot changes slightly, but there is no obvious diffusion; from short wave to long wave range, the diffraction spot distribution is highly concentrated. Therefore, the imaging stability of the spectrophotometer optical system is relatively high, the aberration control effect of the spectrophotometer optical system is good, and it has strong correction ability for off-axis asymmetric coma and astigmatism, and has good imaging quality in a wide spectral range.

[0056] Figure 2The curve diagram of the modulation transfer function of the spectrophotometer optical system of the present application is shown, the uppermost point dash-dot line close to a straight line represents the diffraction limit, which is the theoretically maximum resolving power of the lens assembly, and the other curves are the curve diagrams of the modulation transfer functions of the spectrophotometer optical system of the present application at multiple field angles, it can be seen that the curves of the modulation transfer functions are close to the diffraction limit, and the closer to the diffraction limit, the higher the resolving power of the lens, it can be seen from the diagram that the spectrophotometer optical system proposed in the present application has excellent resolving power.

[0057] Although specific values of various parameters are shown in this embodiment, it should be pointed out that each part of the spectrophotometer optical system is electrically connected with the controller, and the angle and distance can be fine-tuned to adapt to the imaging needs of different object distances; the performance parameters of each optical unit can also be adjusted within the range shown in the present application, and the imaging performance of approximately Figure 1 can also be achieved. That is, the specific parameters not limited in the range above are only examples and do not limit the protection scope of the present application.

[0058] In a specific embodiment of the present application, referring to ​ , in the spectrophotometer optical system, the slit length of the incident slit 2 and the exit slit 6 is 5.5mm, and the width is 0.2mm; as a spectroscopic reflection grating 4, the blazed reflection grating has a grating constant of 4μm, an inclination angle of 22°, and a blazed wavelength of 625nm.

[0059] In a preferred embodiment, the first converging part 1 and / or the second converging part 7 are detachably and telescopically arranged relative to the entire system, which is convenient for assembly in different application scenarios.

[0060] The spectrophotometer optical system of the embodiment of the present application can realize miniaturization and high-quality imaging in the spectral range of 200nm-1100nm, i.e. simultaneously for the spectral range of 200nm-380nm ultraviolet spectral region, 380nm-780nm visible spectral region, and 780nm-1100nm near-infrared spectral region, with good aberration control and wavelength consistency, which meets the design requirements of precision spectral instruments.

[0061] It should be emphasized that the embodiments described in the present application are exemplary rather than limiting, therefore the present application is not limited to the embodiments described in the specific embodiments, and any other embodiments derived from the technical solutions of the present application by those skilled in the art also belong to the protection scope of the present application.

Claims

1. An optical system for a spectrophotometer, characterized in that, The spectrophotometer optical system includes: The first converging part (1) is composed of the first lens (11) and the second lens (12) arranged sequentially along the optical path, the entrance slit (2), the first concave mirror (3), the beam splitting and reflecting grating (4), the second concave mirror (5), the exit slit (6), the second converging part (7) including the third lens (71) and the fourth lens (72), the detection cell (8), the converging lens (9), and the detection part (10). The first lens (11), the second lens (12), the third lens (71) and the fourth lens (72) are all spherical mirrors, and the first concave mirror (3) and the second concave mirror (5) are off-axis concave mirrors; The incident beam enters the first converging part (1), and after being converged by the first lens (11) and the second lens (12) in sequence, it is reflected by the first concave mirror (3) into a parallel beam through the path defined by the incident slit (2). The direction of the parallel beam intersects with the direction of the incident beam. The parallel beam is split and reflected by the beam splitting reflection grating (4) to the second concave mirror (5). It is then reflected by the second concave mirror (5) to form a spectrum and projected onto the exit slit (6) for exit. The exit light is converged through the second converging part (7). The converged beam passes through the detection cell (8), and through the converging lens (9), and is finally detected by the detection part (10). Wherein, the optical power of the spectrophotometer optical system is Φ, the optical power of the first converging part (1) is Φ1, and the optical power of the first lens is Φ 11 The optical power of the second lens (12) is Φ 12 The optical power of the second converging part (7) is Φ7, which satisfies the following relationship: 0.24≤Φ 11 / Φ≤0.29, 0.31≤Φ 12 / Φ≤0.35, 0.13≤Φ 11 +Φ 12 ≤0.2, 0.3≤Φ1 / Φ≤0.41, 0.22≤Φ7 / Φ≤0.35, and the distance from the entrance slit (2) to the object surface of the first lens (11) is less than the distance from the entrance slit (2) to the first concave mirror (3).

2. The spectrophotometer optical system as described in claim 1, characterized in that, The optical power Φ of the third lens (71) 71 The optical power Φ of the fourth lens (72) 72 Satisfying 0.01≤Φ 71 =Φ 72 ≤0.

067.

3. The spectrophotometer optical system according to claim 2, characterized in that, The first concave reflector has a radius of curvature of R1, a tilt angle of θ1, and an eccentricity of Y1, satisfying the following relationships: -0.01≤R1≤-0.006, -13°≤θ1≤-9°, and 6≤Y1≤10.

4. The spectrophotometer optical system according to claim 3, characterized in that, The second concave reflector has a radius of curvature of R2, a tilt angle of θ2, and an eccentricity of Y2, satisfying the following relationships: -0.02≤R2≤-0.005, -20°≤θ2≤-16°, 4≤Y2≤10.

5. The spectrophotometer optical system according to claim 4, characterized in that, The grating constant of the beam-splitting reflective grating is d, and the tilt angle is θ4, satisfying the following relationships: 2μm≤d≤10μm, 14°≤θ4≤25°.

6. The spectrophotometer optical system according to claim 5, characterized in that, The beam-splitting reflective grating (4) is a blazed grating with a blazed wavelength of λ, satisfying the following relationship: 450nm≤λ≤625nm.

7. The spectrophotometer optical system according to claim 6, characterized in that, The exit slit (6) includes a receiving plane for directly receiving optical signals, the tilt angle of the receiving plane being θ6, satisfying the following relationship: 10°≤θ6≤15°.

8. The spectrophotometer optical system as described in claim 7, characterized in that, The optical power Φ9 of the converging lens (9) satisfies 0.01≤Φ9≤0.074 and 0.1≤Φ9 / Φ≤0.23.

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