A parallel light total reflection spectrometer suitable for solar frequency division and a method of using the same

Abstract

The application relates to a parallel light total reflection light splitting prism suitable for solar frequency splitting and a use method thereof. The light splitting prism is made of optical glass and comprises an incident surface, an emitting surface, a first working surface and a second working surface. The incident surface is opposite to the emitting surface, the first working surface is opposite and parallel to the second working surface, and the included angle between the incident surface and the second working surface is equal to a critical angle corresponding to a light splitting wavelength. After parallel light beams are perpendicularly incident on the incident surface, the light beams are sequentially subjected to light splitting for several times through the second working surface, the first working surface, the second working surface, the first working surface and so on, light beams with wavelengths greater than the light splitting wavelength are emitted outside the first working surface and the second working surface, and light beams with wavelengths less than or equal to the light splitting wavelength are perpendicularly emitted by the emitting surface. The parallel light total reflection light splitting prism does not rely on film coating to realize light splitting, but only utilizes light to realize total reflection when the light is incident on a light-lean medium from a light-dense medium at a critical angle or smaller than the critical angle, and realizes refraction when the light is incident on the light-lean medium at a critical angle or greater than the critical angle, so that light splitting is realized.

Description

Technical Field

[0001] This invention belongs to the field of optical instrument design, specifically relating to a parallel light total internal reflection beam splitter suitable for solar energy frequency division and its usage method. Background Technology

[0002] Solar energy, as a natural resource, demonstrates unique advantages due to its abundant reserves and pollution-free nature, and has been internationally recognized as one of the most competitive energy sources for the future. To improve the utilization rate of solar energy, solar thermal, photovoltaic, and photocatalytic systems are often coupled in engineering. For example, in the solar thermal catalytic reaction of carbon dioxide, solar radiation in the catalyst-sensitive spectrum is allocated to the reactor; high-spectral solar radiation is allocated to the solar collector, transferring heat to the reactor, and both work together to carry out the photothermal catalytic reaction. Therefore, the design of solar spectrum frequency division devices has become a hot research topic in the field of solar energy.

[0003] Currently, cutoff filters are commonly used as frequency dividers in engineering, with their working surface being a selective reflection and transmission film system. These thin-film multilayer filters are designed based on the principle of light interference, achieving solar light frequency division by coating antireflection and anti-reflection films onto a quartz plate. However, solar energy utilization devices often add concentrating systems to increase the solar energy receiving area. Considering that solar energy utilization systems often include concentrating devices, this type of filter cannot adapt to high energy flux density beams. Furthermore, the coating process increases the overall cost of the device, thus limiting the widespread adoption of solar energy systems. In addition, there are liquid absorption filters, which use fluids to absorb a portion of the energy for heat generation. While this method is lower in cost, it still has many drawbacks. For example, it requires an additional circulating flow device, increasing the design complexity of the entire system. Therefore, designing a low-cost and highly reliable frequency divider has become a pressing problem in solar energy utilization engineering.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a parallel light total internal reflection beam splitter prism suitable for solar energy frequency division and its usage method, thereby providing a solution for solar energy utilization devices to achieve solar spectrum frequency division utilization.

[0006] This invention is achieved through the following technical solution:

[0007] A parallel light total internal reflection beam splitter suitable for solar frequency division, wherein the beam splitter is optical glass and includes an incident surface, an exit surface, a first working surface and a second working surface; the incident surface and the exit surface are opposite to each other, and the first working surface and the second working surface are opposite to each other and parallel to each other;

[0008] The angle between the incident surface and the second working surface is equal to the critical angle corresponding to the beam splitting wavelength. When the parallel beam is incident perpendicularly from the incident surface, it passes through the second working surface, the first working surface, the second working surface, the first working surface, ... and undergoes several beam splitting events. Light rays with wavelengths greater than the beam splitting wavelength are emitted along the outer side of the first and second working surfaces, while light rays with wavelengths less than or equal to the beam splitting wavelength are emitted perpendicularly from the exit surface.

[0009] Preferably, for optical glass to which the Sellmeier formula applies, the wavelength range of the spectral dispersion is 302.15 nm to 2325.42 nm, and for optical glass to which the Schotto formula applies, the wavelength range of the spectral dispersion is 365.01 nm to 1013.98 nm.

[0010] Preferably, assuming the number of beam splitting operations is n and the angle between the incident surface and the second working surface is θ, the dimensional parameters of the beam splitter prism are as follows:

[0011] When n is odd, the length of the second working surface is (n+1)l / 2cosθ; when n is even, the length of the second working surface is n·l / 2cosθ. When n is odd, the angle between the exiting surface and the second working surface is θ; when n is even, the angle between the exiting surface and the second working surface is 180°-θ.

[0012] Preferably, if the length coefficient k of the incident surface is set, and the critical angle corresponding to the beam splitting wavelength is θ, then the relationship between the length l of the incident surface and the diameter d of the parallel beam is l = d·k / 2sin 2 θ and k take values ​​from 1.5 to 2.

[0013] Furthermore, the incident position of the parallel beam is within a range of k·d from one side of the incident surface to the side of the incident surface.

[0014] Preferably, it further includes a first non-working surface and a second non-working surface arranged opposite to each other, the first non-working surface and the second non-working surface being used for clamping the beam splitter.

[0015] Preferably, the distance between the first non-working surface and the second non-working surface is greater than the length of the incident surface.

[0016] The method of using the parallel light total internal reflection beam splitter prism suitable for solar frequency division is as follows: a parallel light beam is incident perpendicularly from the incident surface. When it reaches the second working surface, light with wavelengths less than or equal to the splitting wavelength undergoes total internal reflection, while light with wavelengths greater than the splitting wavelength undergoes refraction and reflection, thus achieving the first beam splitting. The light after the first reflection reaches the first working surface for the second beam splitting, and the light after the second reflection reaches the second working surface for the third beam splitting, and so on, to achieve several beam splittings. The reflected light is then emitted through the exit surface.

[0017] Preferably, the light emitted through the exiting surface is used for photocatalytic reaction, and the light emitted through the first working surface and the second working surface is used for heat generation.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The parallel light total internal reflection beam-splitter prism for solar energy frequency division described in this invention achieves beam splitting without relying on coating. It utilizes the fact that light incident from an optically denser medium to an optically less dense medium at or below the critical angle undergoes total internal reflection, while light incident from an optically denser medium to an optically less dense medium at an angle greater than the critical angle undergoes refraction, thus achieving beam splitting. The beam splitting wavelength of the prism can be arbitrarily set within permissible limits according to usage requirements, splitting the beam into two beams of different wavelengths: one greater than the specified wavelength and the other less than or equal to it. This invention utilizes the characteristics of total internal reflection to achieve beam splitting, effectively reducing light energy loss. The overall splitting efficiency of the prism in this invention can reach 85%, with light energy loss less than 10%. Furthermore, compared to existing beam splitting devices, this invention can meet the requirements for high-energy beam splitting, has better durability and reliability, and a wider range of applications. Overall, the prism of this invention has advantages such as compact structure, high reliability, convenient processing, and low manufacturing cost. This invention can adapt to complex engineering application environments and can effectively improve the light energy utilization efficiency of various solar-driven photocatalysis, photothermal catalysis, photoelectrocatalysis and photovoltaic systems. It can provide efficient and convenient light energy frequency division utilization for various solar energy utilization devices.

[0020] Furthermore, by selecting an appropriate incident surface length coefficient, the incident position of the beam can be shifted within a certain range, which can simplify debugging and installation; Attached Figure Description

[0021] Figure 1 The prism designed according to the present invention;

[0022] Figure 2 The optical path diagrams are shown for rays with wavelengths greater than the split wavelength (a) and for rays with wavelengths less than or equal to the split wavelength (b).

[0023] Figure 3 This is a dimensional diagram of the beam-splitting prism in an example of the present invention;

[0024] Figure 4 This is one mounting method for the beam splitter prism in an example of the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Incident surface; 2. Exit surface; 3. First working surface; 4. Second working surface; 5. First non-working surface; 6. Second non-working surface. Detailed Implementation

[0027] To facilitate further understanding by those skilled in the art, the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be noted that various modifications and alterations can be made to the present invention without departing from its concept and principles, and all such modifications and alterations fall within the scope of protection of the present invention.

[0028] like Figure 1 The parallel light total internal reflection beam splitter for solar frequency division described in this invention is formed by an incident surface 1, an exit surface 2, a first working surface 3, a second working surface 4, a first non-working surface 5, and a second non-working surface 6; the incident surface 1 is opposite to the exit surface 2, the first working surface 3 is opposite to and parallel to the second working surface 4, and the first non-working surface 5 is opposite to the second non-working surface 6.

[0029] The angle between the incident surface 1 and the second working surface 4 is equal to the critical angle corresponding to the wavelength of the beam. When the parallel beam is incident perpendicularly from the incident surface 1, it undergoes several beam splits through the second working surface 4, the first working surface 3, the second working surface 4, the first working surface 3, ... Finally, the light with a wavelength greater than the wavelength of the beam splits is emitted along both sides of the first working surface 3 and the second working surface 4, while the light with a wavelength less than or equal to the wavelength of the beam splits is emitted perpendicularly from the exit surface 2. The first non-working surface 5 and the second non-working surface 6 can be used for clamping the prism.

[0030] The beam-splitting prism of this invention is made of optical glass. Based on size and efficiency requirements, a suitable grade of optical glass is selected, and the beam-splitting prism of this invention can be obtained through simple machining. For optical glass applicable to the Sellmeier formula, the beam-splitting wavelength range is 302.15 nm to 2325.42 nm; for optical glass applicable to the Schotto formula, the beam-splitting wavelength range is 365.01 nm to 1013.98 nm. The beam-splitting wavelength can be selected according to actual working needs.

[0031] Given a length coefficient k and a critical angle θ corresponding to the splitting wavelength, the relationship between the length l of the incident surface 1 and the beam diameter d is l = d·k / 2sinθ. 2θ and k take values ​​from 1.5 to 2. The incident position of the parallel beam is within a range of k·d from one side of the incident surface 1, with the optimal incident point being the middle position within this range. By selecting an appropriate length coefficient, the incident position of the beam can be shifted within a certain range.

[0032] Based on size and efficiency requirements, select an appropriate number of beam splitting operations, where 2 ≤ number of beam splitting operations ≤ 8. Design the beam splitting prism based on the number of beam splitting operations. Let the number of beam splitting operations be n. Then the prism's dimensional parameters are as follows: When n is odd, the length of the second working surface 4 is (n+1)l / 2cosθ; when n is even, the length of the second working surface 4 is n·l / 2cosθ; the angle between the incident surface 1 and the second working surface 4 is θ; when n is odd, the angle between the exit surface 2 and the second working surface 4 is θ; when n is even, the angle between the exit surface 2 and the second working surface 4 is 180°-θ.

[0033] The parallel light total internal reflection beam-splitter prism for solar frequency division described in this invention achieves beam splitting without relying on coating. It utilizes the characteristic that light undergoes total internal reflection when incident from an optically denser medium to an optically less dense medium at or below a critical angle. It achieves beam splitting by refracting light with wavelengths greater than the splitting wavelength and by total internal reflection of light with wavelengths less than or equal to the splitting wavelength. This invention is applicable when the light beam is parallel and the incident direction is perpendicular to the incident plane 1.

[0034] Example

[0035] A beam splitter prism is designed for a solar photothermal catalytic reaction device, using the infrared portion with wavelengths greater than 750nm for heat generation, and the visible and ultraviolet portions with wavelengths less than 750nm for the photocatalytic reaction. Therefore, in this example, the beam splitting wavelength is 750nm.

[0036] In this example, to improve the spectrophotometry, the number of spectrophotometers is selected as 7.

[0037] Considering that this example requires the use of infrared light, and that the beam is split seven times, resulting in a long optical path within the prism, optical glass with a high internal transmittance is chosen. Taking into account factors such as price, HFK61B fluorine crown optical glass manufactured by Chengdu Guangming Optoelectronics Co., Ltd. is selected.

[0038] Assuming the diameter of the parallel beam obtained by the focusing device is 12mm, a length factor of 1.5 is selected.

[0039] The beam splitter design is described below. Based on the Sellmeier dispersion formula, the refractive index of HFK61B glass for 750nm light is calculated to be 1.49330026, and the incident angle for each beam split is calculated to be 42.040650°. Based on this angle, the number of splits, the beam diameter, and the length coefficient, the beam splitter in this example can be designed, as shown in the attached diagram. Figure 3 As shown.

[0040] When the light beam is incident perpendicularly from the incident surface 1, the angle of incidence is 0°, and the direction of the light does not change. When the light first reaches the second working surface 4, the refractive index of light with wavelengths less than or equal to 750nm in the prism is greater than 1.49330026, therefore its critical angle is less than or equal to the angle of incidence, resulting in total internal reflection. Similarly, the critical angle corresponding to light with wavelengths greater than 750nm is greater than the angle of incidence, resulting in refraction and reflection. Among them, the light emitted by refraction is light with wavelengths greater than 750nm, and the light retained in the prism by reflection is the full spectrum. The light after the first reflection reaches the first working surface 3 and continues the above-mentioned beam splitting process. After completing 7 refraction and reflection beam splitting processes, the unrefracted light with wavelengths less than or equal to 750nm and a small portion of the light with wavelengths greater than 750nm retained by reflection are emitted perpendicularly from the exit surface 2.

[0041] It should be noted that when the number of beam splits is odd, the angle between the outgoing ray and the incident ray is twice the incident angle, which is 84.0813° in this example; when the number of beam splits is even, the outgoing ray and the incident ray are parallel.

[0042] The optical losses in the entire device mainly occur in the following processes: 1) partially reflected light when incident perpendicularly; 2) partially reflected light when emitted perpendicularly; 3) light propagation loss within the prism. Reflection loss can be calculated using Fresnel's formula; propagation loss can be calculated using the transmittance in the optical glass grade table combined with the optical path length.

[0043] The refractive index of the entire device can be calculated using Fresnel's formula combined with the number of refractions. The longer the wavelength of light, the higher the refractive index.

[0044] To ensure a high refractive index, prisms can be made from optical materials with lower refractive indices or by increasing the number of refractions. However, more refractions increase the optical path length within the prism, leading to increased propagation losses. Therefore, these factors should be fully considered during the design process, and the number of refractions should be flexibly selected based on actual operating conditions.

[0045] In this example, a spectral splitting efficiency greater than 90% and a light energy loss of less than 10% can be achieved.

[0046] To verify the correctness of this invention, the optical path of the beam splitter designed in this example was simulated using the ray tracing module of the optics section of COMSOL 5.6. The results are as follows. Figure 2 As shown. Figure 2 (a) shows the propagation path of light with a wavelength greater than 750 nm; Figure 2(b) shows the propagation path of light with a wavelength less than or equal to 750 nm. The simulation results are consistent with the theoretical analysis.

[0047] Figure 3 This is the machining drawing for the prism in this example. The prism designed according to this invention has an isosceles trapezoidal cross-section. During machining, the bottom surface is used as the reference surface, and it can be obtained with only simple machining, which has the advantage of being easy to manufacture.

[0048] The thickness of the prism should take into full account the clamping. The thickness of the prism, i.e., the distance between the first non-working surface 5 and the second non-working surface 6, should be greater than the length of the incident surface 1. Figure 4 Given a clamping method, where light is incident in the direction indicated by the arrow.

[0049] In summary, the present invention can split parallel beams using a low-cost method, and has certain practical engineering value.

Claims

1. A parallel light total internal reflection beam splitter suitable for solar energy frequency division, characterized in that, The beam splitter is optical glass and includes an incident surface (1), an exit surface (2), a first working surface (3), and a second working surface (4); the incident surface (1) is opposite to the exit surface (2), and the first working surface (3) is opposite to and parallel to the second working surface (4); The angle between the incident surface (1) and the second working surface (4) is equal to the critical angle corresponding to the beam splitting wavelength. When the parallel beam is incident perpendicularly from the incident surface (1), it passes through the second working surface (4), the first working surface (3), the second working surface (4), the first working surface (3), ... and undergoes several beam splitting events. The light with a wavelength greater than the beam splitting wavelength is emitted out along the outside of the first working surface (3) and the second working surface (4), while the light with a wavelength less than or equal to the beam splitting wavelength is emitted perpendicularly from the exit surface (2). Let the number of spectroscopic steps be... n The angle between the incident surface (1) and the second working surface (4) is θ The dimensions of the beam splitter are as follows: when n When the length is odd, the length of the second working face (4) is ,when n When the number is even, the length of the second working face (4) is ;when n When the angle is odd, the angle between the exit surface (2) and the second working surface (4) is... θ ,when n When the number is even, the angle between the exit surface (2) and the second working surface (4) is ; Set the length factor of the incident surface (1) k The critical angle corresponding to the wavelength of the spectral split is θ Then the length of the incident surface (1) l Diameter of parallel beam d The relationship is , k The value ranges from 1.5 to 2; The incident position of the parallel beam is located at a distance of from the incident surface (1) to the incident surface (1) at a distance of _ Within the range.

2. The parallel light total internal reflection beam splitter prism suitable for solar frequency division according to claim 1, characterized in that, For optical glass using the Sellmeier formula, the wavelength range for spectral dispersion is 302.15 nm to 2325.42 nm; for optical glass using the Schotto formula, the wavelength range is 365.01 nm to 1013.98 nm.

3. The parallel light total internal reflection beam splitter prism suitable for solar frequency division according to claim 1, characterized in that, It also includes a first non-working surface (5) and a second non-working surface (6) arranged opposite to each other, the first non-working surface (5) and the second non-working surface (6) being used for clamping the beam splitter.

4. The parallel light total internal reflection beam splitter prism suitable for solar frequency division according to claim 3, characterized in that, The distance between the first non-working surface (5) and the second non-working surface (6) is greater than the length of the incident surface (1).

5. The method of using the parallel light total internal reflection beam splitter prism suitable for solar frequency division as described in any one of claims 1 to 4, characterized in that, When a parallel beam is incident perpendicularly from the incident surface (1) and reaches the second working surface (4), light with wavelengths less than or equal to the beam splitting wavelength undergoes total internal reflection, while light with wavelengths greater than the beam splitting wavelength undergoes refraction and reflection, thus achieving the first beam splitting. After the first reflection, the light reaches the first working surface (3) for the second beam splitting, and after the second reflection, the light reaches the second working surface (4) for the third beam splitting. This process is repeated several times to achieve beam splitting. The reflected light is then emitted through the exit surface (2).

6. The method of using the parallel light total internal reflection beam splitter prism suitable for solar frequency division according to claim 5, characterized in that, The light emitted through the exit surface (2) is used for photocatalytic reaction, and the light emitted through the first working surface (3) and the second working surface (4) is used for heat generation.

Images