Visual naked eye display VOC detection system

Abstract

The utility model belongs to the technical field of optical detection, and discloses a visual naked eye display VOC (volatile organic compound) detection system. A backlight source generation system in the VOC detection system comprises a laser, a collimation assembly, an optical fiber coupling assembly, a laser shimming assembly and a parallel collimation assembly, through complex two-dimensional aspheric curved surfaces at the tops of two Powell prisms, a large amount of spherical aberration can be generated when laser passes through, a light path is redistributed, and a large amount of spherical aberration can be generated when the laser passes through the two-dimensional aspheric curved surfaces. After collimation, a uniform rectangular light field is generated as a backlight source; in addition, the optical detection system comprises a reflecting mirror, a liquid crystal sensing element and a polarization analyzer, the polarization state of light generated by the backlight source is changed through the liquid crystal sensing element, the brightness change of a specific pattern is observed in combination with the polarization analyzer, and therefore rapid and accurate detection of VOC is achieved. The utility model overcomes the problems of large volume and complex detection system of the existing optical detection device, and has important research significance and application value in the field of optical detection.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical detection, and particularly relates to a VOC detection system with visual naked-eye display. Background Art

[0002] With the rapid development of artificial intelligence, computer, optical sensing and semiconductor technologies, visualization technology has become an important branch of computer science. By simulating the perception ability of the human eye, visualization technology converts data into perceivable forms such as graphics, symbols, colors, textures, etc., greatly enhancing the data recognition efficiency and the effect of information transmission. In recent years, significant progress has been made in visualization display technology, which enables observers to directly observe with the naked eye without relying on large-scale observation instruments, greatly simplifying the observation process and reducing the dependence on professional detection equipment.

[0003] In the field of environmental monitoring, VOCs are a class of chemical substances with high vapor pressure, which are easily present in the air in the form of vapor at normal temperature and widely come from various aspects of life and production, such as fuel combustion, transportation, industrial production, building materials and furniture emissions, etc. Since the emissions of VOCs pose a threat to the atmospheric environment and human health, the detection of volatile organic compounds (VOCs) is particularly important. Traditional VOC detection methods mostly use a polarizing microscope for observation and characterization. This method requires placing the sample between a polarizer and an analyzer, and judging the presence of VOC gas by observing the pattern changes in the field of view. However, this detection system is complex and bulky, bringing many inconveniences to the actual detection work, especially in on-site rapid detection and real-time monitoring.

[0004] Therefore, in order to overcome the limitations of traditional detection methods and improve the efficiency and convenience of VOC detection, we propose. How to design a simple and small-sized detection device by combining modern visualization display technology and optical sensing technology, and be able to achieve rapid and accurate detection of VOC gas, and display the detection results through direct naked-eye observation, providing strong technical support for environmental monitoring and VOC treatment. Summary of the Utility Model

[0005] Aiming at the problems of the traditional VOC detection method in the background art, such as complex system and large volume, it is difficult to meet the requirements of on-site rapid detection and real-time monitoring. We realize the optical detection of harmful gases by combining a liquid crystal sensing element and an analyzer. Based on this, the utility model provides a VOC detection system with visual naked-eye display.

[0006] To achieve the above object, the present utility model adopts the following technical solutions: A VOC detection system for visual naked-eye display, comprising a laser. The laser outputs a Gaussian beam as a point light source. A collimating component, a fiber optic coupling component, a laser beam homogenizing component, and a parallel collimating component are sequentially arranged on the outgoing light path of the laser. A reflecting mirror is arranged on the outgoing light path of the parallel collimating component. A liquid crystal sensing element is arranged on the outgoing light path of the reflecting mirror. The liquid crystal sensing element is used to change the polarization state of specific light emitted by the backlight source and detect the gas. A polarizer is placed on the liquid crystal sensing element. The polarizer is used to modulate the brightness of the outgoing light field to realize visual observation of the detection result. The collimating component reshapes the Gaussian beam emitted by the laser into a collimated elliptical spot. The fiber optic coupling component is used to perform secondary shaping on the collimated elliptical spot to obtain a spot with a diameter of 0.8 mm. The laser beam homogenizing component is used to perform a third shaping on the 0.8 mm spot to obtain a uniform light field with a fixed divergence angle and uniform energy distribution. The parallel collimating component is used to perform a fourth shaping on the uniform light field to obtain a rectangular light field as the backlight source for visual naked-eye display detection.

[0007] As a further explanation and limitation of the above technical solution, the collimating component is a circular aspherical lens made of plastic material, with a diameter of 5 mm and a focal length of 6 mm.

[0008] As a further explanation and limitation of the above technical solution, the fiber optic coupling component is composed of a coupling lens, a multimode fiber, and an aspherical collimating mirror. The focal length of the coupling lens is 10 mm, the numerical aperture is 0.25, and the material is B270 glass material, and an antireflection film is coated on it. The wavelength range of the antireflection film is 350 - 750 nm. The multimode fiber is a step-index multimode fiber with a quartz core and a fluorine-doped glass cladding, with a numerical aperture of 0.22 and a fiber diameter of 200 μm. The focal length of the aspherical collimating mirror is 2 mm, the numerical aperture is 0.50, and an antireflection film is coated on it. The wavelength range of the antireflection film is 350 - 750 nm.

[0009] As a further explanation and limitation of the above technical solution, the laser beam homogenizing component includes a first Powell prism and a second Powell prism, and the gap between the two is 0 mm, and the azimuth angles differ by 90°. The fan angle of the first Powell prism is 30°, the conic coefficient is -2.35, the radius of curvature is 0.612 mm, the size is 6.30 mm × 6.30 mm × 5.85 mm, and the material is BK7. The fan angle of the second Powell prism is 60°, the size is 6.30 mm × 6.30 mm × 5.85 mm, the conic coefficient is -1.38, the radius of curvature is 0.330 mm, and the material is BK7.

[0010] As a further explanation and limitation of the above technical solution, the parallel collimation component includes a first plano-convex lens and a second plano-convex lens placed vertically and orthogonally. The focal length of the first plano-convex lens is 50.8 mm, the radius of curvature is 26.4 mm, the height is 50.8 mm, the length is 53.0 mm, the central thickness is 21.6 mm, and the edge thickness is 2.0 mm. An antireflection film is coated on the first plano-convex lens, and the wavelength range of the antireflection film is 350 - 750 nm; the focal length of the second plano-convex lens is 75.6 mm, the radius of curvature is -39.1 mm, the height is 50.8 mm, the length is 53.0 mm, the central thickness is 12.4 mm, and the edge thickness is 3.0 mm. An antireflection film is coated on the second plano-convex lens, and the wavelength range of the antireflection film is 350 - 750 nm.

[0011] As a further explanation and limitation of the above technical solution, the reflectivity of the mirror is 100%, and its setting angle is 45°, which is used to deflect the light emitted from the rectangular light field from the horizontal propagation direction to the vertical direction.

[0012] As a further supplementary description of the above technical solution, the liquid crystal sensing element is a liquid crystal wave plate array, and its distance from the mirror is 200 mm.

[0013] As a further supplementary description of the above technical solution, the distance between the analyzer and the liquid crystal sensing element is 10 mm.

[0014] As a further supplementary description of the above technical solution, the laser is a semiconductor laser, which is fixed on the optical platform by a fixture.

[0015] As a further explanation and limitation of the above technical solution, the laser is specifically a laser diode module, which is cylindrical with a size of 6 mm × 21 mm, the output wavelength is 520 ± 10 nm, and the power is 5 mW.

[0016] Compared with the prior art, the beneficial effects of the present utility model are mainly reflected in the following aspects:

[0017] 1. By adopting the combination of an aspherical lens and a Powell prism, the present utility model can achieve precise shaping of the Gaussian beam, enabling the beam to diverge at a fixed angle in the horizontal and vertical directions to form a surface light source with uniform energy distribution. This design not only solves the problem of large energy density at the center and small energy density at both sides in traditional beam shaping technology, but also obtains a rectangular light field with extremely high illumination uniformity and a small beam angle through further shaping by the parallel collimation component, meeting the high requirements of the visual naked-eye display system for the backlight source.

[0018] 2. The present utility model combines a liquid crystal sensing element and a polarizer, enabling the observation of changes in specific patterns in the optical path, providing a means of high sensitivity and high precision for the detection of volatile organic compounds (VOCs). The specific orientation and patterning of the liquid crystal waveplate array enable the system to accurately capture the optical changes caused by VOCs, achieving rapid and accurate detection of VOCs.

[0019] 3. The design of the present utility model has a high degree of flexibility and scalability. By adjusting parameters such as the sector angle, size, and material of the Powell prism, as well as parameters such as the focal length and size of the lenses in the parallel collimation component, customization of backlight sources with different sizes and different lighting requirements can be achieved. In addition, the specific patterns and orientations of the liquid crystal sensing elements can also be designed and adjusted according to actual needs to meet the requirements of different detection tasks.

[0020] 4. The present utility model adopts a simple and compact structural design, which is easy to implement and maintain. At the same time, due to the use of standardized optical elements and components, the reliability and stability of the system are effectively guaranteed.

[0021] 5. The present utility model provides an optical system that is efficient, highly accurate, easy to implement and maintain, and is particularly suitable for the backlight sources of visual naked-eye display systems and the field of VOC detection, having broad application prospects and market potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a structural diagram of the VOC detection system for visual naked-eye display in the present utility model;

[0023] Figure 2 is the illuminance distribution diagram of the backlight source in the present utility model;

[0024] Figure 3 is a schematic diagram of the pattern change of the liquid crystal sensing element in the present utility model.

[0025] In the figure: 1 is a laser, 2 is a collimation component, 3 is an optical fiber coupling component, 4 is a laser beam homogenizing component, 5 is a parallel collimation component; 6 is a reflector, 7 is a liquid crystal sensing element, 8 is a polarizer, 31 is an aspherical coupling mirror, 32 is a multimode optical fiber, 33 is an aspherical collimating mirror, 41 is the first Powell prism, 42 is the second Powell prism, 51 is the first plano-convex lens, 52 is the second plano-convex lens. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0026] In order to further elaborate on the technical solution of the present utility model, the following combines the attached Figures 1 to 3 , according to the design scheme and detection principle, we further illustrate the present utility model through the optimal embodiment.

[0027] As shown in the attachedFigure 1 As shown in the figure, a VOC detection system for visual naked-eye display includes a laser 1. The laser 1 outputs a Gaussian beam as a point light source. A collimation component 2, an optical fiber coupling component 3, a laser beam homogenization component 4, and a parallel collimation component 5 are sequentially arranged on the outgoing light path of the laser 1. A reflector 6 is arranged on the outgoing light path of the parallel collimation component 5. A liquid crystal sensing element 7 is arranged on the outgoing light path of the reflector 6. The liquid crystal sensing element 7 is used to change the polarization state of the specific light emitted by the backlight source and detect gases. An analyzer 8 is placed on the liquid crystal sensing element 7. The distance between the analyzer 8 and the liquid crystal sensing element 7 is 10 mm. The analyzer 8 is used to modulate the brightness of the outgoing light field to realize visual observation of the detection result.

[0028] In the above embodiment, the laser 1 is a semiconductor laser, specifically a laser diode module, which is fixed on the optical platform by a fixture. The laser diode module is cylindrical with a size of 6 mm × 21 mm, an output wavelength of 520 ± 10 nm, and a power of 5 mW. Of course, to ensure good heat dissipation, its housing is made of copper. The reflectivity of the reflector 6 is 100%, and its arrangement angle is 45°, which is used to deflect the light emitted by the rectangular light field from the horizontal propagation direction to the vertical direction.

[0029] In a preferred embodiment, the collimation component 2 is an aspherical lens made of plastic, with a focal length of 6 mm. The collimation component 2 reshapes the Gaussian beam emitted by the laser 1 into a collimated elliptical light spot.

[0030] Preferred embodiment: The fiber optic coupling component 3 consists of a coupling lens 31, a multimode optical fiber 32, and an aspherical collimating mirror 33. The coupling lens 31 has a focal length of 20 mm, a numerical aperture of 0.60, and is made of B270 glass material with an antireflection coating deposited on it. The wavelength range of the antireflection coating is 350 - 750 nm. The multimode optical fiber 32 is a step-index multimode optical fiber with a quartz core and a fluorine-doped glass cladding, having a numerical aperture of 0.22, a fiber diameter of 200 μm, the same size at the incident end and the output end, and the same thickness. The aspherical collimating mirror 33 has a focal length of 2 mm, a numerical aperture of 0.50, and an antireflection coating deposited on it with a wavelength range of 350 - 750 nm. In the specific implementation process, the curved surface of the coupling lens 31 faces the light source incident direction and is coaxial with the light source incident direction. Under the condition of meeting the coupling condition, the fiber incident end face is placed facing the light incident direction at a distance approximately equal to the focal length of the coupling lens 31 and is coaxial with the light. After the focused light spot enters the optical fiber 32 for transmission at a certain angle, according to the total internal reflection principle, the light will be reflected multiple times inside the optical fiber to achieve full mode mixing of the light beam. The light beam output from the output end of the optical fiber 32 passes through an aspherical lens collimation 33. The plane of the lens faces the output light beam and is placed coaxial with the output light beam of the optical fiber 32 to obtain a collimated Gaussian light beam with a diameter of approximately 0.8 mm.

[0031] Preferred embodiment: The laser beam homogenizing component 4 includes a first Powell prism 41 and a second Powell prism 42, with a gap of 0 mm between them and an azimuth difference of 90°. The fan angle of the first Powell prism 41 is 30°, the conic coefficient is -2.35, the radius of curvature is 0.612 mm, the size is 6.30 mm × 6.30 mm × 5.85 mm, the material is BK7, and the curved surface convex rib is vertical and placed facing the light source incident direction. The fan angle of the second Powell prism 42 is 60°, the size is 6.30 mm × 6.30 mm × 5.85 mm, the conic coefficient is -1.38, the radius of curvature is 0.330 mm, the material is BK7, and the curved surface convex rib is horizontal and placed facing the light source incident direction. In the specific implementation process, when the 0.8 mm diameter collimated Gaussian light is incident on the laser beam homogenizing group 4, the aspherical curved surface of the convex surface of the Powell prism causes a large amount of spherical aberration in the incident light spot, making the energy distribution of the light beam a surface light source that diverges at a fixed angle and has a uniform energy distribution, greatly changing the uneven phenomenon of high energy density in the center of the light beam and low energy density on both sides brought about by shaping the Gaussian light beam with a cylindrical lens.

[0032] Preferred embodiment, the parallel collimation assembly 5 includes a first plano-convex lens 51 and a second plano-convex lens 52 placed vertically and orthogonally. The focal length of the first plano-convex lens 51 is 50.8 mm, the radius of curvature is 26.4 mm, the height is 50.8 mm, the length is 53.0 mm, the central thickness is 21.6 mm, and the edge thickness is 2.0 mm. An anti-reflection film is coated on the first plano-convex lens 51, and the wavelength range of the anti-reflection film is 350 - 750 nm. The curved surface of the first plano-convex lens 51 is horizontally curved, and the plane faces the light source. The focal length of the second plano-convex lens 52 is 75.6 mm, the radius of curvature is -39.1 mm, the height is 50.8 mm, the length is 53.0 mm, the central thickness is 12.4 mm, and the edge thickness is 3.0 mm. An anti-reflection film is coated on the second plano-convex lens 52, and the wavelength range of the anti-reflection film is 350 - 750 nm. The curved surface of the second plano-convex lens 52 is vertically curved, and the plane faces the light source. The convex surface of the first plano-convex lens 51 faces the direction of the light emitted by the laser homogenizing assembly 4, coaxial with the light, and is 30 mm away from the rear surface of the second Powell prism 42. The plane of the second plano-convex lens 52 faces the direction of the light emitted by the laser homogenizing assembly 4, coaxial with the light, and is 74 mm away from the rear surface of the second Powell prism 42. The distance between the two plano-convex lenses is 22 mm. In the specific implementation process, the spot shaped by the Powell prism is a uniform surface light source that diverges at a fixed angle in the horizontal and vertical directions. After being shaped by the parallel collimation assembly 5, a rectangular light field with a length × width of approximately 40 mm × 22 mm is obtained. We use the middle part with a length × width of approximately 20 mm × 20 mm as the backlight source for the visual naked-eye display detection device.

[0033] As Figure 2 shown, according to the illuminance of the backlight source, it can be seen that the light in the selected area is evenly distributed on the illumination surface, and the backlight source has a very high illumination uniformity. Select the central area of the illumination plane, and calculate the average error to measure the illumination uniformity. The average error is the ratio of the standard deviation of illuminance to the average value of illuminance:

[0034] Among them,

[0035] In the formula: σ is the standard deviation of illuminance, n is the number of sampled pixels, and xi is the illuminance value on the i-th sampled pixel. is the average illuminance on the illumination surface, and v is the average error of the illuminance. Then the illumination uniformity is: U = (1 - v) × 100%. According to the above formula, it can be calculated that the illumination uniformity of the collimated backlight source designed in Embodiment 1 on the illumination plane is 95.2%. By sampling and analyzing the light intensity on the illumination plane at different angles, it is obtained that the included angle of the light beam is less than 6°. In the existing backlight technology, usually achieving an illumination uniformity of 95% and a divergence angle of less than 8° are two difficult-to-balance indicators. This shows that the backlight source designed by the method of the present invention has good collimation and uniformity, meeting the requirements of the visual naked-eye display system for the backlight source.

[0036] As shown in the attached Figure 3 figure, the liquid crystal sensing element 7 is an array of liquid crystal wave plates. Each array is oriented in a specific direction and undergoes special patterning treatment. As Figure 1 shown. By combining with the analyzer 8, a specific pattern can be observed, and it should be placed at a position 200 mm away from the outgoing light path of the mirror 6. In the specific implementation process, the light emitted from the rectangular light field irradiates the liquid crystal wave plate array. When combined with the analyzer 8, after introducing volatile organic compounds (VOCs), a change in the specific pattern can be observed.

[0037] The above shows and describes the main features and advantages of the present utility model. For those skilled in the art, it is obvious that the specific implementation manners of the present utility model are not limited to the details of the above exemplary embodiments. Moreover, without departing from the spirit or basic features of the present utility model, the creative ideas and design concepts of the present utility model can be implemented in other specific forms, which should be equally within the protection scope disclosed in the technical solutions of the present utility model. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present utility model.

[0038] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A VOC detection system with visual naked-eye display, comprising a laser (1), characterized in that: The laser (1) outputs a Gaussian beam as a point light source. A collimator component (2), an optical fiber coupling component (3), a laser shim component (4), and a parallel collimator component (5) are sequentially arranged on the output light path of the laser (1). A reflector (6) is arranged on the output light path of the parallel collimator component (5). A liquid crystal sensor element (7) is arranged on the output light path of the reflector (6). The liquid crystal sensor element (7) is used to change the polarization state of specific light emitted by the backlight source and detect gas. A polarizer (8) is placed on the liquid crystal sensor element (7). The polarizer (8) is used to modulate the brightness of the output light field to achieve visual observation of the detection result. The collimating component (2) shapes the Gaussian beam emitted by the laser (1) into a collimated elliptical light spot; The optical fiber coupling component (3) is used to perform secondary shaping on the collimated elliptical light spot to obtain a light spot with a diameter of 0.8 mm; The laser shim assembly (4) is used to perform a third shaping on the 0.8 mm light spot to obtain a uniform light field with a fixed divergence angle and uniform energy distribution; The parallel collimation component (5) is used to perform a fourth shaping on the uniform light field to obtain a rectangular light field, and the middle part is used as a backlight source for visual naked eye display detection.

2. A VOC detection system with visual naked eye display according to claim 1, characterized in that: The collimating component (2) is an aspheric lens made of plastic material and has a focal length of 6 mm.

3. A VOC detection system with visual naked eye display according to claim 2, characterized in that: The optical fiber coupling component (3) comprises a coupling lens (31), a multimode optical fiber (32), and an aspheric collimator (33). The coupling lens (31) has a focal length of 10 mm and a numerical aperture of 0.25, and is made of B270 glass material, on which an anti-reflection film is coated, and the wavelength range of the anti-reflection film is 350-750 nm. The multimode optical fiber (32) is a step-refractive-index multimode optical fiber with a quartz core and a fluorine-doped glass cladding, with a numerical aperture of 0.22 and a fiber diameter of 200 μm. The aspheric collimator (33) has a focal length of 2 mm and a numerical aperture of 0.50, and is coated with an anti-reflection film, and the wavelength range of the anti-reflection film is 350-750 nm.

4. A VOC detection system with visual naked eye display according to claim 3, characterized in that: The laser shim assembly (4) comprises a first Powell prism (41) and a second Powell prism (42), the gap between the two being 0 mm, the azimuth angles differing by 90°, the first Powell prism (41) having a sector angle of 30°, a cone coefficient of -2.35, a curvature radius of 0.612 mm, a size of 6.30 mm×6.30 mm×5.85 mm, and a material of BK7; the second Powell prism (42) having a sector angle of 60°, a cone coefficient of -1.38, a curvature radius of 0.330 mm, a size of 6.30 mm×6.30 mm×5.85 mm, and a material of BK7.

5. A VOC detection system with visual naked eye display according to claim 4, characterized in that: The parallel collimation assembly (5) comprises a first plano-convex lens (51) and a second plano-convex lens (52) which are arranged vertically and orthogonally. The first plano-convex lens (51) has a focal length of 50.8 mm, a radius of curvature of 26.4 mm, a height of 50.8 mm, a length of 53.0 mm, a center thickness of 21.6 mm, and an edge thickness of 2.0 mm. The first plano-convex lens (51) is coated with an anti-reflection film, and the wavelength range of the anti-reflection film is 350-750 nm. The second plano-convex lens (52) has a focal length of 75.6 mm, a radius of curvature of 39.1 mm, a height of 50.8 mm, a length of 53.0 mm, a center thickness of 12.4 mm, and an edge thickness of 3.0 mm. The second plano-convex lens (52) is coated with an anti-reflection film, and the wavelength range of the anti-reflection film is 350-750 nm.

6. A VOC detection system with visual naked eye display according to claim 5, characterized in that: The reflectance of the reflector (6) is 100%, and its arrangement angle is 45°, and it is used to deflect the light emitted by the rectangular light field from the horizontal propagation direction to the vertical direction.

7. A VOC detection system with visual naked eye display according to claim 6, characterized in that: The liquid crystal sensing element (7) is a liquid crystal wave plate array, and the distance between the liquid crystal sensing element and the reflector (6) is 200 mm.

8. A VOC detection system with visual naked eye display according to claim 7, characterized in that: The distance between the polarizer (8) and the liquid crystal sensor element (7) is 10 mm.

9. A VOC detection system with visual naked-eye display according to any one of claims 1 to 8, characterized in that: The laser (1) is a semiconductor laser, which is fixed on an optical platform by a clamp.

10. A VOC detection system with visual naked eye display according to claim 9, characterized in that: The laser (1) is a laser diode module, which is cylindrical in size of 6 mm×21 mm, has an output wavelength of 520±10 nm, and a power of 5 mW.

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