Ultra-wide-angle dual-channel laser alarm lens

Abstract

The utility model relates to an ultra-wide-angle dual-channel laser alarm lens, and the lens comprises a negative-focal-power front group which comprises a first lens, a second lens and a third lens, the first lens, the second lens and the third lens are sequentially arranged in the light incident direction, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the object side surface and the image side surface of the second lens are concave surfaces; the object side surface of the third lens is a concave surface, and the image side surface is a convex surface; the spectroscope is arranged at the light emitting end of the front group with the negative focal power, and the included angle between the spectroscope and the optical axis is 45 degrees; the non-imaging rear group is arranged at the transmission end of the spectroscope; and the imaging rear group is arranged at the reflecting end of the spectroscope and is vertical to the non-imaging rear group. As the spectroscope is arranged between the front group with the negative focal power and the non-imaging rear group, and the imaging rear group is arranged at the reflecting end of the spectroscope, a dual-channel alarm form combining non-imaging and imaging is realized, and meanwhile, the lens utilizes the front group with the negative focal power to realize compression of off-axis large-view-field light and realize an ultra-large view field angle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser warning, in particular to a super-wide-angle dual-channel laser warning lens. BACKGROUND

[0002] With the development of laser detection, laser guidance and other laser technologies and their wide application in related fields, how to quickly and accurately identify enemy detection and attack laser signals, obtain intelligence and improve platform survivability is the key to achieving photoelectric countermeasure advantage. As an important component of existing photoelectric countermeasure equipment, the laser warning device needs to realize wide range airspace warning. When it monitors laser ranging, laser guidance and other laser threats, it will timely issue a warning and guide the countermeasure system to take appropriate countermeasure and protection measures. High resolution, low false alarm rate and wide angle laser warning device can accurately detect the direction of laser threat sources in a wide range and improve the countermeasure effectiveness of the countermeasure system, and has become the focus of laser warning technology research. The performance of the laser warning lens directly affects the accuracy of the laser warning device.

[0003] Conventional laser warning devices can be divided into two types: non-imaging type and imaging type. The non-imaging type mostly uses PIN detectors to confirm the direction of laser light sources by using array distributed detectors. Its advantage is that it can realize real-time warning and has low false alarm rate, but its disadvantage is low angular resolution. The imaging type mostly uses short-wave detectors. Its advantage is that it has high resolution and higher angular accuracy, but its disadvantage is that from the end of image integration to the end of signal reading, the time period is the "dead zone" of light signal response, which leads to false alarm phenomenon when receiving narrow pulse laser signals during non-integration. The existing laser warning lens has small field of view, and generally four or more distributed laser warning lenses are used to realize 360° airspace warning. SUMMARY

[0004] The present application provides a super-wide-angle dual-channel laser warning lens to solve the deficiencies of laser warning devices in angular resolution, false alarm, field of view and false alarm rate in related technologies.

[0005] In a first aspect, a super-wide-angle dual-channel laser warning lens is provided, comprising:

[0006] a front group with negative focal power, comprising a first lens, a second lens and a third lens arranged in sequence along the light incident direction, the object side of the first lens is convex, and the image side is concave; the object side and the image side of the second lens are both concave; the object side of the third lens is concave, and the image side is convex;

[0007] a beam splitter placed at the light exit end of the front group with negative focal power, and the included angle with the optical axis is 45°;

[0008] The non-imaging rear group, having positive optical power, is placed at the transmission end of the beam splitter;

[0009] The imaging post-group, having positive optical power, is placed at the reflective end of the beam splitter and is set perpendicularly to the non-imaging post-group.

[0010] In some embodiments, the ultra-wide-angle dual-channel laser alarm lens satisfies:

[0011] 34.1≤D1 / f1≤47.2;

[0012] 20.5≤D1 / f2≤24.8;

[0013] Where D1 is the effective aperture of the first lens, f1 is the focal length of the non-imaging rear group, and f2 is the focal length of the imaging rear group.

[0014] In some embodiments, both the object-side and image-side surfaces of the beam splitter are planar;

[0015] And / or, the object side of the beam splitter has a beam-splitting film;

[0016] And / or, the image side of the beam splitter is coated with a laser antireflection film.

[0017] In some embodiments, the non-imaging rear group includes at least a non-imaging aperture, a non-imaging first lens, a non-imaging filter, a non-imaging second lens, a non-imaging third lens, and a non-imaging fourth lens arranged sequentially along the incident direction of light.

[0018] In some embodiments, the imaging back group includes at least an imaging aperture, an imaging first lens, an imaging filter, a cemented lens, and an imaging third lens arranged sequentially along the light refraction direction.

[0019] In some embodiments, the surface of the non-imaging filter is coated with narrow bands that allow transmission in the 0.98μm, 1.064μm, and 1.535μm to 1.57μm wavelength ranges;

[0020] And / or, the non-imaging aperture ranges from 6mm to 10mm.

[0021] In some embodiments, the surfaces of the non-imaging first lens, non-imaging second lens, non-imaging third lens, and non-imaging fourth lens are all coated with a laser anti-reflection film.

[0022] In some embodiments, the surface of the imaging filter is coated with narrow bands that allow transmission in the 0.98μm, 1.064μm, and 1.535μm to 1.57μm wavelength ranges;

[0023] And / or, the imaging aperture ranges from 2mm to 6mm.

[0024] In some embodiments, the surfaces of the imaging first lens, the cemented lens, and the imaging third lens are all coated with a laser anti-reflection film.

[0025] In some embodiments, the protective window, located at the light incident end of the first lens, is a lens of uniform thickness, with its object side being convex and its image side being concave, and the image side being coated with a laser anti-reflection film.

[0026] This application provides an ultra-wide-angle dual-channel laser alarm lens. By placing a beam splitter between the negative optical power front group and the non-imaging rear group, and placing the imaging rear group at the reflective end of the beam splitter, a dual-channel alarm form combining non-imaging and imaging is achieved. This allows the two alarm forms to complement each other, improving the alarm angular resolution while reducing the false alarm rate compared to a single alarm form, thereby enhancing the performance of the laser alarm. Simultaneously, the lens utilizes a negative optical power front group with positive and negative lens elements to compress off-axis light rays with a large field of view, reducing the angle of view incident on the imaging and non-imaging rear groups, thus achieving an ultra-wide field of view. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A cross-sectional structural diagram of the ultra-wide-angle dual-channel laser alarm lens provided in the embodiments of this application.

[0029] In the diagram: 1. Protective window; 2. First lens; 3. Second lens; 4. Third lens; 5. Beam splitter; 6. Non-imaging aperture; 7. Non-imaging first lens; 8. Non-imaging filter; 9. Non-imaging second lens; 10. Non-imaging third lens; 11. Non-imaging fourth lens; 12. Imaging aperture; 13. Imaging first lens; 14. Imaging filter; 15. Cemented lens; 16. Imaging third lens; 17. Non-imaging rear group; 18. Imaging rear group; 19. Front group with negative optical power. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] This application provides an ultra-wide-angle dual-channel laser alarm lens, which can solve the shortcomings of laser alarm devices in related technologies in terms of angular resolution, missed alarms, field of view, and false alarm rate.

[0032] like Figure 1 As shown, an ultra-wide-angle dual-channel laser warning camera includes:

[0033] The front group 19 has negative optical power;

[0034] Beam splitter 5 is placed at the light-emitting end of the front group 19 with negative optical power, and the angle between it and the optical axis is 45°.

[0035] The non-imaging rear group 17, with positive optical power, is placed at the transmission end of the beam splitter 5.

[0036] The imaging post-group 18, which has positive optical power, is placed at the reflective end of the beam splitter 5 and is set perpendicular to the non-imaging post-group 17.

[0037] Specifically, since a beam splitter 5 is set between the front group 19 with negative optical power and the non-imaging rear group 17, and an imaging rear group 18 is set at the reflecting end of the beam splitter 5, the non-imaging rear group 17 uses the real-time alarm of the PI N detector to achieve a general alarm of the laser target with a low false alarm rate. At the same time, the imaging rear group 18 uses the high precision of the short-wave detector to improve the angular resolution of the laser alarm and achieve a fine alarm. This realizes a dual-channel alarm form that combines non-imaging and imaging, so that the advantages of the two alarm forms complement each other. Compared with a single alarm form, it improves the angular resolution of the alarm while reducing the false alarm rate, thereby improving the performance of the laser alarm.

[0038] Furthermore, the lens is equipped with a protective window 1, which is located at the light incident end of the first lens 2. It is a lens of equal thickness and made of H-K9L, a commonly used material for lasers. It has good optical performance and its material properties are more stable and reliable. At the same time, a hard protective film is coated on the outer surface of the protective window 1 to enhance the lens's ability to operate in complex environments.

[0039] Furthermore, the object side of the protective window 1 is convex, while the image side is concave, which facilitates the sliding off of rainwater, etc. The image side is coated with a laser anti-reflection film, which has an anti-reflection effect on lasers in the 0.9μm to 1.7μm wavelength band.

[0040] Furthermore, the negative optical power front group 19 includes a first lens 2, a second lens 3 and a third lens 4 arranged sequentially along the incident direction of light. The object side of the first lens 2 is convex and the image side is concave. Both the object side and the image side of the second lens 3 are concave. The object side of the third lens 4 is concave and the image side is convex.

[0041] Specifically, by using the front group 19 with negative optical power and a combination of positive and negative lenses, the large off-axis field of view light is compressed, reducing the field of view angle incident on the rear imaging group 18 and the non-rear imaging group 17, thereby achieving an ultra-large field of view angle.

[0042] Furthermore, the ultra-wide-angle dual-channel laser warning lens meets the following requirements:

[0043] 34.1≤D1 / f1≤47.2;

[0044] 20.5≤D1 / f2≤24.8;

[0045] Where D1 is the effective aperture of the first lens 2, f1 is the focal length of the non-imaging rear group, and f2 is the focal length of the imaging rear group.

[0046] Specifically, the effective aperture of the first lens 2 and the focal length relationship between the two channels are set. Firstly, this constrains the relationship between the lens size and shape and the focal length, giving the lens focusing relationship data value, thereby quantifying the optical design configuration. Secondly, within this range, the optimal effect of the required parameters is designed.

[0047] Furthermore, both the object side and the image side of the beam splitter 5 are planar.

[0048] Furthermore, the object side of the beam splitter 5 has a beam splitting film, which is used to realize dual-channel alarm. The beam splitting film is applied to the object side to split the compressed light in the front group, so that part of the energy is reflected into the imaging back group 18 and reaches the shortwave detector, and the other part of the energy is transmitted into the non-imaging back group 17 and reaches the PI N detector.

[0049] Furthermore, based on the performance differences between the shortwave detector and the PIN detector, the beam splitter with a beam splitting film coated on the object side of the beam splitter has a splitting ratio of 2:8, that is, 20% is reflected and 80% is transmitted, so that 20% of the energy reaches the shortwave detector and 80% of the energy reaches the PIN detector.

[0050] Furthermore, the image side of the beam splitter 5 is coated with a laser antireflection film, which has an antireflection effect on lasers in the 0.9μm to 1.7μm wavelength range.

[0051] Furthermore, in this embodiment, the non-imaging rear group 17 includes a non-imaging aperture 6, a non-imaging first lens 7, a non-imaging filter 8, a non-imaging second lens 9, a non-imaging third lens 10, and a non-imaging fourth lens 11 arranged sequentially along the light incident direction.

[0052] Specifically, the non-imaging first lens 7, non-imaging second lens 9, non-imaging third lens 10, and non-imaging fourth lens 11 are all lenses that converge light rays. Their main function is to refract light rays and correct aberrations so that the light rays converge onto the PIN detector. The main function of the non-imaging first lens 7 is to refract light rays to create a quasi-parallel optical path. The non-imaging second lens 9, non-imaging third lens 10, and non-imaging fourth lens 11 have similar functions, used to correct aberrations and converge the light rays that have passed through the non-imaging filter 8 onto the detector.

[0053] In some embodiments, the number of lenses can be increased or decreased, but this will affect image quality. More lenses can better correct aberrations, but will increase costs, reduce system transmittance, and affect alarm distance; conversely, reducing the number of lenses will make aberration correction more difficult and may require the introduction of complex aspherical surfaces.

[0054] In this application, the non-imaging filter 8 is optimally positioned behind the non-imaging first lens 7 because its position is a quasi-parallel optical path. This results in a smaller incident angle of light from the non-imaging filter 8, better filter manufacturing, a narrower narrow band, better stray light filtering, and a higher system signal-to-noise ratio. If the non-imaging filter 8 is placed in other positions, the incident angle will be larger, and the effect will not be optimal.

[0055] Furthermore, the surface of the non-imaging filter 8 is coated with narrow bands that allow transmission in the 0.98μm, 1.064μm, and 1.535μm to 1.57μm wavelength ranges, thereby achieving selective transmission of the laser wavelength range reaching the PI N detector.

[0056] Furthermore, the non-imaging aperture 6 has a diameter range of 6mm to 10mm, and its main function is to act as a field stop to limit the light entering the non-imaging channel.

[0057] Furthermore, the surfaces of the non-imaging first lens 7, the non-imaging second lens 9, the non-imaging third lens 10, and the non-imaging fourth lens 11 are all coated with a laser anti-reflection film, which has an anti-reflection effect on lasers in the 0.9μm to 1.7μm wavelength band.

[0058] In this embodiment, the imaging rear group 18 includes an imaging aperture 12, an imaging first lens 13, an imaging filter 14, a cemented lens 15, and an imaging third lens 16 arranged sequentially along the light refraction direction.

[0059] Specifically, similar to the principle of the non-imaging rear group 17, the imaging first lens 13, the cemented lens 15, and the imaging third lens 16 are all lenses that converge light rays. Their main function is to refract light rays and correct aberrations so that the light rays converge onto the shortwave detector. Among them, the cemented lens 15 can perform aberration correction, resulting in better imaging to the shortwave detector and improving alarm accuracy.

[0060] The surface of the imaging filter 14 is coated with narrow bands that allow transmission in the 0.98μm, 1.064μm, and 1.535μm to 1.57μm wavelength ranges, thereby enabling selective transmission of the laser wavelength range reaching the shortwave detector.

[0061] Furthermore, the imaging aperture 12 has a diameter range of 2mm to 6mm, and its main function is also to limit the light entering the imaging channel as a field stop.

[0062] Furthermore, the surfaces of the imaging first lens 13, the cemented lens 15, and the imaging third lens 16 are all coated with a laser anti-reflection film, which has an anti-reflection effect on lasers in the 0.9μm to 1.7μm wavelength band.

[0063] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0064] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0065] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An ultra-wide field-of-view dual-channel laser warning lens, characterized in that, It comprises: a front group (19) with negative focal length, comprising a first lens (2), a second lens (3) and a third lens (4) arranged in sequence along the light incident direction, the object side of the first lens (2) is convex, and the image side is concave; the object side and the image side of the second lens (3) are both concave; the object side of the third lens (4) is concave, and the image side is convex; a beam splitter (5) placed at the light exit end of the front group (19) with negative focal length, with an angle of 45° with the optical axis; a non-imaging rear group (17) with positive focal length, placed at the transmission end of the beam splitter (5); an imaging rear group (18) with positive focal length, placed at the reflection end of the beam splitter (5), and arranged perpendicularly to the non-imaging rear group (17).

2. The ultra-wide-angle dual-channel laser warning lens of claim 1, wherein: the ultra-wide-angle dual-channel laser warning lens satisfies: 34.1≤D1 / f1≤47.2; 20.5≤D1 / f2≤24.8; wherein D1 is the effective aperture of the first lens (2), f1 is the focal length of the non-imaging rear group, and f2 is the focal length of the imaging rear group.

3. The ultra-wide-angle dual-channel laser warning lens of claim 1, wherein: the object side and the image side of the beam splitter (5) are both flat; and / or, the object side of the beam splitter (5) has a beam splitting film; and / or, the image side of the beam splitter (5) is coated with a laser anti-reflection film.

4. The ultra-wide-angle dual-channel laser warning lens of claim 1, wherein: the non-imaging rear group (17) comprises at least a non-imaging diaphragm (6), a non-imaging first lens (7), a non-imaging filter (8), a non-imaging second lens (9), a non-imaging third lens (10) and a non-imaging fourth lens (11) arranged in sequence along the light incident direction.

5. The ultra-wide-angle dual-channel laser warning lens of claim 1, wherein: the imaging rear group (18) comprises at least an imaging diaphragm (12), an imaging first lens (13), an imaging filter (14), a cemented lens (15) and an imaging third lens (16) arranged in sequence along the light incident direction.

6. The ultra-wide-angle dual-channel laser warning lens of claim 4, wherein: the surface of the non-imaging filter (8) is coated with a narrow band of 0.98μm, 1.064μm, 1.535μm-1.57μm wavelength band; and / or, the aperture range of the non-imaging diaphragm (6) is 6mm-10mm.

7. The ultra-wide-angle dual-channel laser warning lens of claim 4, wherein: the surfaces of the non-imaging first lens (7), the non-imaging second lens (9), the non-imaging third lens (10) and the non-imaging fourth lens (11) are all coated with a laser anti-reflection film.

8. The ultra-wide-angle dual-channel laser warning lens of claim 5, wherein: the surface of the imaging filter (14) is coated with a narrow band of 0.98μm, 1.064μm, 1.535μm-1.57μm wavelength band; and / or, the aperture range of the imaging diaphragm (12) is 2mm-6mm.

9. The ultra-wide angle dual-channel laser warning mirror lens according to claim 5, characterized in that: The surfaces of the imaging first lens (13), the cemented lens (15) and the imaging third lens (16) are coated with laser anti-reflection films.

10. The ultra-wide angle dual channel laser warning lens of claim 1, wherein, Further comprising: A protective window (1) is arranged at the light incident end of the first lens (2), which is an equal-thickness lens, the object side is convex, the image side is concave, and the image side is coated with a laser anti-reflection film.

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