Infrared front lens

Abstract

The invention discloses an infrared front lens, which comprises a lens body group, a rear lens group and a connecting bracket group, the rear lens group is connected to the rear end of the lens body group, and the two ends of the connecting support group are detachably connected with the infrared front lens and an external white light sighting telescope respectively. The lens body group comprises a lens body, an infrared objective lens group and an infrared movement group which are sequentially arranged in the lens body, and a control panel, a power supply group, a focusing group and a wireless communication group which are arranged on the side surface of the lens body; an eyepiece group and a display screen are arranged in the rear lens group. The infrared front lens can be assembled with a white light sighting telescope to achieve infrared sighting, and is comprehensive in function and suitable for complex scenes.

Description

Technical Field

[0001] The invention relates to the field of optical sights, and in particular to an infrared front mirror. Background Art

[0002] At present, in order to expand the day and night use of white light sights and improve the all-weather combat effectiveness of weapon systems, infrared sights are often installed on them to achieve functional connection, which has a large market demand. However, the current infrared front mirrors generally have simple functions and are not enough to meet actual needs. Summary of the invention

[0003] The purpose of the present invention is to provide an infrared front mirror, which has the functions of focusing, vision adjustment and wireless communication, can adapt to complex environments and meet various usage requirements.

[0004] In order to solve the above technical problems, the present invention provides an infrared front mirror, comprising: a mirror body group, a rear mirror group, and a connecting bracket group; the rear mirror group is connected to the rear end of the mirror body group, and the two ends of the connecting bracket group are respectively detachably connected to the infrared front mirror and the external white light sight; The mirror body group includes a mirror body, an infrared objective lens group and an infrared movement group arranged in sequence in the mirror body, and a control panel, a power supply group, a focus adjustment group and a wireless communication group arranged on the side of the mirror body; An eyepiece group and a display screen are arranged in the rear mirror group. According to the above scheme, the infrared movement group includes an infrared movement and a movement base, the infrared movement is fixed on the movement base, and the movement base is fixed to the mirror body.

[0005] According to the above scheme, the control panel includes a mirror cover plate, and a button group, an encoder group, and a wireless communication group fixed to the mirror cover plate; The mirror body cover plate is fixed to the mirror body; The key group includes a key circuit board and a first key cover, the key circuit board is fixed to the mirror body cover plate, and the wireless communication group includes a wireless communication cover plate connected to the mirror body cover plate; The encoder group comprises an encoder and an encoder handwheel group. The encoder is fixed to the mirror cover plate, and the control end of the encoder is connected to the encoder handwheel group.

[0006] According to the above scheme, the power supply group includes a battery, a battery compartment, a battery cover group, and an electrode group. The battery compartment is located on the side of the mirror body, the electrode group is arranged at the bottom of the battery compartment, the battery is arranged in the battery compartment, and the battery cover group is detachably connected to the battery compartment; the battery cover group and the electrode group are electrically connected to the negative pole and the positive pole of the battery respectively.

[0007] According to the above scheme, the focusing group includes an inner distance adjusting wheel, a focusing handwheel, and a focusing screw. The inner distance adjusting wheel is rotatably connected to the lens body, the focusing handwheel is fixed to the outer side of the inner distance adjusting wheel, a curved groove is provided on the inner side surface of the inner distance adjusting wheel, and a straight groove is provided on the lens body. One end of the focusing screw is located in the curved groove, and the other end thereof passes through the straight groove and is threadedly connected to the infrared objective lens group.

[0008] According to the above scheme, the connecting bracket group includes a connecting seat, and the two ends of the connecting seat are provided with open rings respectively connected to the eyepiece group and the external white light sight, and a locking mechanism is provided on the open ring.

[0009] According to the above solution, the battery compartment is at a certain oblique angle compared to the axis of the mirror body.

[0010] According to the above scheme, an interface with a certain hole spacing is set on the scope body, and a standard Picatinny rail is fixed to the interface of the scope body.

[0011] According to the above scheme, the eyepiece optical system in the eyepiece group includes a first meniscus lens, a double convex lens, a second meniscus lens, a third meniscus lens, a fourth meniscus lens, and a fifth meniscus lens, which are arranged in sequence from the human eye to the display screen, wherein the first meniscus lens and the double convex lens are closely connected to form a cemented lens.

[0012] According to the above scheme, the focal length fa of the cemented lens satisfies: 58.71mm<fa<64.89mm; The focal length fb of the second meniscus lens satisfies: 32.34mm<fb<35.75mm; The focal length fc of the third meniscus lens satisfies: 17.80mm<fc<19.67mm; The focal length fd of the fourth meniscus lens satisfies 40.24 mm<fd<44.48 mm; The focal length fe of the fifth meniscus lens satisfies 29.36 mm<fe<32.45 mm; The air gap between the cemented lens and the second meniscus lens is 0.3±0.03mm, the air gap between the second meniscus lens and the third meniscus lens is 2.73±0.03mm, the air gap between the third meniscus lens and the fourth meniscus lens is 3.54±0.03mm, and the air gap between the fourth meniscus lens and the fifth meniscus lens is 0.3±0.03mm.

[0013] Beneficial Effects The present invention can realize the assembly of the infrared front mirror and the white light sight through the provided connecting bracket group, so that the white light sight has an infrared aiming function; the aiming parameters are adjusted through the provided control panel to adapt to actual aiming requirements, and the provided wireless communication group enables the infrared front mirror to transmit the video signal to the display terminal wirelessly, thereby improving the use efficiency and convenience. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a side view of an infrared front mirror according to an embodiment of the present invention; Figure 2 yes Figure 1 AA section view; Figure 3 is a structural diagram of an optical system of an eyepiece assembly according to an embodiment of the present invention; Figure 4 is an exploded schematic diagram of a mirror body assembly according to an embodiment of the present invention; Figure 5 is an exploded schematic diagram of a key group according to an embodiment of the present invention; Figure 6 is a cross-sectional view of a focusing group according to an embodiment of the present invention; Figure 7 is an exploded schematic diagram of an encoder group according to an embodiment of the present invention; Figure 8 is a cross-sectional view of a battery cover assembly according to an embodiment of the present invention; Fig. 9 is a schematic diagram of an explosion of an electrode assembly according to an embodiment of the present invention; Fig.10 A connecting bracket assembly according to an embodiment of the present invention; Fig.11 Schematic diagram of the curved groove of the inner spacing wheel according to an embodiment of the present invention; Fig.12 is a spot diagram of an optical system of an eyepiece assembly according to an embodiment of the present invention; Fig.13 4 is a field curvature distortion diagram of the eyepiece optical system according to an embodiment of the present invention.

[0015] In the figure: 1-infrared objective lens group, 2-lens body group, 3-rear mirror group, 4-control panel, 5-eyepiece group, 6-focusing group, 7-encoder group, 8-battery cover group, 9-electrode group, 10-connection bracket group; 201-scope body, 202-movement seat, 203-focusing gasket, 204-scope body screw sleeve, 205-lead slot plate, 206-standard Picatinny rail, 207-TYPE-C gasket, 208-sealing gasket, 209-wire screw sleeve, 210-TYPE-C interface, 211-infrared movement, 212-first screw, 213-second screw, 214-negative plate, 215-third screw, 216-fourth screw, 217-fifth screw, 218-sixth screw, 219-seventh screw; 401-mirror body cover, 402-first button cover, 403-WIFI cover, 404-first button gasket, 405-eighth screw, 406-button circuit board; 50101-first meniscus lens, 50102-biconvex lens, 502-second meniscus lens, 503-third meniscus lens, 504-fourth meniscus lens, 505-fifth meniscus lens; 601-focusing hand wheel, 602-inner distance adjustment wheel, 603-focusing pressure ring, 604-focusing screw, 605-focusing label, 606-ninth screw, 607-first sealing ring, 608-second sealing ring, 609-focusing spring; 701- encoder hand wheel, 702- second button cover, 703- second button gasket, 704- encoder button pressure ring, 705- encoder second pressure ring, 706- third sealing ring, 707- encoder first pressure ring, 708- tenth screw, 709- encoder; 801-battery cover, 802-battery cover screw sleeve, 803-electrode gasket, 804-electrode spring, 805-fourth sealing ring; 901-electrode ring, 902-electrode pressing ring, 903-positive electrode sheet, 904-electrode pad; 1001-connecting seat, 1002-locking handle, 1003-locking screw, 1004-locking nut, 1005-lock nut, 1006-cylindrical pin, 1007-gasket, 1008-corrugated gasket, 1009-anti-slip cloth. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0017] This embodiment provides an infrared front mirror, comprising: a mirror body group 2, a rear mirror group 3, and a connecting bracket group 10; the rear mirror group 3 is connected to the rear end of the mirror body group 2, and the two ends of the connecting bracket group 10 are respectively detachably connected to the infrared front mirror and the external white light sight; The mirror body 201 group 2 includes a mirror body 201, and an infrared objective lens group 1 and an infrared movement 211 group arranged in sequence in the mirror body 201, and a control panel 4, a power supply group, a focus adjustment group 6, and a wireless communication group arranged on the side of the mirror body 201; An eyepiece group 5 and a display screen are arranged in the rear mirror group 3 .

[0018] Furthermore, the infrared movement 211 group includes an infrared movement 211 and a movement base 202 , the infrared movement 211 is fixed on the movement base 202 , and the movement base 202 is fixed to the mirror body 201 .

[0019] Furthermore, the infrared movement 211 seat 202 is fixed to the movement seat 202 by a fourth screw 216, and the movement seat 202 is fixed to the mirror body 201 by a fifth screw 217; and a plurality of stacked focusing gaskets 203 are arranged between the movement seat 202 and the mirror body 201, and the number of focusing gaskets 203 is determined by the focusing effect of the infrared front mirror during assembly.

[0020] Furthermore, there is a large gap between the through hole on the movement seat 202 for the fifth screw 217 to pass through and the outer diameter of the threaded portion of the fifth screw 217 (the single-side gap is 0.4 mm in the embodiment of the present invention), which is convenient for calibrating the position between the infrared movement 211 and the optical axis (providing a certain adjustment space).

[0021] Furthermore, a TYPE-C interface 210 is fixed to the infrared core 211 by a sixth screw 218 , and a TYPE-C gasket 207 is provided between the TYPE-C interface 210 and the infrared core 211 .

[0022] Furthermore, the control panel 4 is fixed to the mirror body 201 by a seventh screw 219 .

[0023] Furthermore, the control panel 4 includes a mirror body cover plate 401, and a button group, an encoder group 7, and a wireless communication group (a WIFI group in this embodiment) fixed to the mirror body cover plate 401; The mirror body cover plate 401 is fixed to the mirror body 201 by the seventh screw 219; The button group includes a button circuit board 406 and a first button cover 402. The button circuit board 406 is fixed to the mirror body cover plate 401 by an eighth screw 405. The wireless communication group includes a wireless communication cover plate (a WIFI cover 403 in this embodiment) connected to the mirror body cover plate 401. The encoder group 7 includes an encoder 709 and an encoder handwheel group. The encoder 709 is fixed to the mirror cover plate 401 , and the control end of the encoder 709 is connected to the encoder handwheel 701 group.

[0024] Furthermore, a first key pad 404 is disposed between the first key cover 402 and the key circuit board 406 , and the first key pad 404 is adhered to the bottom of the key of the first key cover 402 to enhance the operation feel of the key.

[0025] Furthermore, the encoder 709 is fixed to the mirror cover 401 through the encoder first pressure ring 707, the encoder handwheel 701 group includes an encoder handwheel 701, a second button cover 702, and an encoder button pressure ring 704, the second button cover 702 is fixed in the encoder handwheel 701 through the encoder button pressure ring 704, and the encoder button pressure ring 704 is provided with a waist-shaped groove connected to the control end of the encoder 709.

[0026] Furthermore, a second key pad 703 is disposed between the second key cover 702 and the encoder 709 .

[0027] Furthermore, the encoder group 7 includes an encoder second pressure ring 705 and a tenth screw 708. The encoder second pressure ring 705 is fixed on the mirror cover 401, and an annular groove is provided on its side. The encoder handwheel 701 is sleeved on the encoder second pressure ring 705. The tenth screw 708 passes through the encoder handwheel 701 and its inner end is located in the annular groove. The tenth screw 708 is used to limit the axial position of the encoder handwheel 701 without affecting the rotation of the encoder handwheel 701.

[0028] Furthermore, a third sealing ring 706 is provided on the side of the second encoder pressing ring 705 , and the third sealing ring 706 is located between the second encoder pressing ring 705 and the encoder handwheel 701 .

[0029] Furthermore, the power supply group includes a battery, a battery compartment, a battery cover group 8, and an electrode group 9. The battery compartment is located on the side of the mirror body 201, the electrode group 9 is arranged at the bottom of the battery compartment, the battery is arranged in the battery compartment, and the battery cover group 8 is detachably connected to the battery compartment; the battery cover group 8 and the electrode group 9 are electrically connected to the negative pole and the positive pole of the battery, respectively.

[0030] Furthermore, the electrode group 9 includes an electrode pad 904, a positive electrode sheet 903, an electrode spring 804, an electrode pressure ring 902, and an electrode ring 901, which are sequentially arranged at the bottom of the battery compartment; the positive electrode sheet 903 is located in the electrode pad 904, the electrode spring 804 is welded to the positive electrode sheet 903, an annular groove is arranged on the outer side of the electrode ring 901, the electrode pressure ring 902 is sleeved on the annular groove of the electrode ring 901, and the outer side of the electrode pressure ring is threadedly connected to the battery compartment (the electrode ring 901 presses the electrode sheet and the electrode pad 904 to the bottom of the battery compartment); the electrode pad 904 and the electrode pressure ring 902 are made of ABS material, and the electrode ring 901 is made of silicone rubber, all of which have insulating effects.

[0031] Furthermore, the battery cover assembly 8 includes a battery cover 801, an electrode spring 804, an electrode gasket 803, and a battery cover screw sleeve 802; a groove is provided at the inner bottom of the battery cover 801, the electrode spring 804 is provided in the groove of the battery cover 801, and the electrode gasket 803 and the battery cover screw sleeve 802 are fixed to the inner side of the battery cover 801 in sequence.

[0032] Furthermore, the electrode gasket 803 is interference-fitted with the battery to compress the battery and prevent the battery from loosening due to shooting vibration.

[0033] Furthermore, a fourth sealing ring 805 is provided on the outer side of the battery cover screw sleeve 802 .

[0034] Furthermore, the electrode spring 804 located in the battery cover group 8 and the electrode group 9 is electrically connected to the negative electrode and the positive electrode of the battery respectively; the internal thread and the groove of the battery cover 801 are treated with oxygen breaking, the battery cover screw sleeve 802 and the battery cover 801 are fixed by conductive glue, and the battery cover screw sleeve 802 is connected to the battery compartment through the lens body screw sleeve 204 made of conductive material (copper in this embodiment); a threaded hole treated with oxygen breaking is provided on the lens body 201, and a conductive third screw 215 is connected in the threaded hole, and the third screw 215 fixes the negative electrode sheet 214 to the lens body 201, and the negative electrode line is welded to the negative electrode sheet.

[0035] Furthermore, the positive wire is welded on the positive electrode sheet 903, and the positive wire is inserted into the mirror body 201 through a lead groove with holes on the side of the battery compartment; the lead groove is closed by a lead groove sealing plate; the lead groove plate 205 is fixed to the mirror body 201 by a second screw 213, and a sealing gasket 208 is arranged between the lead groove plate 205 and the mirror body 201.

[0036] Furthermore, the focusing group 6 includes an inner distance adjusting wheel 602, a focusing hand wheel 601, and a focusing screw 604. The inner distance adjusting wheel 602 is rotatably connected to the lens body 201. The focusing hand wheel 601 is fixed to the outer side of the inner distance adjusting wheel 602. A curved groove is provided on the inner side surface of the inner distance adjusting wheel 602. A straight groove is provided on the lens body 201. One end of the focusing screw 604 is located in the curved groove, and the other end thereof passes through the straight groove and is threadedly connected to the infrared objective lens group 1.

[0037] Furthermore, the inner distance adjustment wheel 602 is rotationally connected to the mirror body 201 through a focus pressure ring 603 threadedly connected to the mirror body 201 .

[0038] Furthermore, the focusing hand wheel 601 is fixed to the inner distance adjusting wheel 602 via a ninth screw 606 , a focusing label 605 is provided on the outer side of the ninth screw 606 , and the focusing label 605 is connected to the focusing hand wheel 601 .

[0039] Furthermore, a first sealing ring 607 is provided between the inner distance adjustment wheel 602 and the mirror body 201 , and a second sealing ring 608 is provided between the focusing hand wheel 601 and the mirror body 201 .

[0040] Furthermore, a focusing spring 609 is provided between the infrared objective lens group 1 and the lens body 201 .

[0041] Furthermore, the connecting bracket group 10 includes a connecting seat 1001, and two ends of the connecting seat 1001 are provided with open rings respectively connected to the eyepiece group 5 and the external white light sight, and a locking mechanism is provided on the open ring.

[0042] Furthermore, an anti-slip cloth 1009 is pasted on the inner wall of the open ring.

[0043] Furthermore, the locking mechanism includes a locking handle 1002, a cylindrical pin 1006, a locking screw 1003, a gasket 1007, a corrugated gasket 1008, a locking nut 1004, and a stop nut 1005. A boss with a through hole is provided at the opening of the open ring. One end of the locking screw 1003 is rotatably connected to the locking handle 1002 through the cylindrical pin 1006, and the other end thereof passes through the gasket 1007, the boss of the open ring, and the corrugated gasket 1008 in turn, and is threadedly connected to the locking nut 1004 and the stop nut 1005 in turn.

[0044] Furthermore, the gasket 1007 is made of steel and is used to reduce the wear between the locking handle 1002 and the boss of the open ring.

[0045] Furthermore, the locking handle 1002 and the cylindrical pin 1006 are in interference fit.

[0046] Furthermore, the battery compartment is at a certain oblique angle relative to the axial direction of the mirror body 201, so that the battery can be replaced normally when the infrared front mirror is installed and connected to the bracket assembly 10.

[0047] Furthermore, an interface with a certain hole spacing (40 mm in this embodiment) is provided on the scope body 201, and the interface of the scope body 201 is fixed with a standard Picatinny rail 206 by a first screw 212; the standard Picatinny rail 206 can be used to install external devices to expand the function of the infrared front mirror; in other embodiments of the present invention, the interface may also adopt other types of connection structures.

[0048] Furthermore, the eyepiece group 5 moves axially in the rear lens group 3 by rotating (for adjusting the diopter), and the rear lens group 3 includes a stop ring, which is used to prevent the eyepiece group 5 from being rotated out.

[0049] Furthermore, the rear end of the eyepiece group 5 is connected to a diopter adjustment hand wheel, and the rear end of the diopter adjustment hand wheel is connected to an eyepiece cover; it should be understood that when the infrared front mirror is assembled with the connecting bracket group 10, the eyepiece cover should be removed first.

[0050] Furthermore, the eyepiece optical system in the eyepiece group 5 includes a first meniscus lens 50101, a biconvex lens 50102, a second meniscus lens 502, a third meniscus lens 503, a fourth meniscus lens 504, and a fifth meniscus lens 505, which are arranged in sequence from the human eye to the display screen, wherein the first meniscus lens 50101 and the biconvex lens 50102 are closely connected to form a cemented lens.

[0051] Furthermore, the focal length fa of the cemented lens satisfies: 58.71 mm<fa<64.89 mm; The focal length fb of the second meniscus lens 502 satisfies: 32.34 mm<fb<35.75 mm; The focal length fc of the third meniscus lens 503 satisfies: 17.80 mm<fc<19.67 mm; The focal length fd of the fourth meniscus lens 504 satisfies 40.24 mm<fd<44.48 mm; The focal length fe of the fifth meniscus lens 505 satisfies 29.36 mm<fe<32.45 mm.

[0052] Furthermore, the air gap between the cemented lens and the second meniscus lens 502 is 0.3±0.03mm, the air gap between the second meniscus lens 502 and the third meniscus lens 503 is 2.73±0.03mm, the air gap between the third meniscus lens 503 and the fourth meniscus lens 504 is 3.54±0.03mm, and the air gap between the fourth meniscus lens 504 and the fifth meniscus lens 505 is 0.3±0.03mm.

[0053] The eyepiece optical system used in this embodiment adopts a deformed Kenel eyepiece structure, gradually increases the number of field lenses, so that the light can be projected smoothly, reduces the light deflection angle, and effectively ensures the image quality under the condition of a large exit pupil. The magnification reaches 10 times, the focal length is 25mm, and the exit pupil distance is 20mm.

[0054] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0055] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An infrared front mirror, characterized in that: include: A mirror body group, a rear mirror group, and a connecting bracket group; the rear mirror group is connected to the rear end of the mirror body group, and the two ends of the connecting bracket group are detachably connected to the infrared front mirror and the external white light sight respectively; The mirror body group includes a mirror body, an infrared objective lens group and an infrared movement group arranged in sequence in the mirror body, and a control panel, a power supply group, a focus adjustment group and a wireless communication group arranged on the side of the mirror body; An eyepiece group and a display screen are arranged in the rear mirror group.

2. The infrared front mirror according to claim 1, characterized in that: The infrared movement group comprises an infrared movement and a movement base. The infrared movement is fixed on the movement base, and the movement base is fixed on the mirror body.

3. The infrared front mirror according to claim 1, characterized in that: The control panel includes a mirror cover plate, and a button group, an encoder group, and a wireless communication group fixed to the mirror cover plate; The mirror body cover plate is fixed to the mirror body; The key group includes a key circuit board and a first key cover, the key circuit board is fixed to the mirror body cover plate, and the wireless communication group includes a wireless communication cover plate connected to the mirror body cover plate; The encoder group comprises an encoder and an encoder handwheel group. The encoder is fixed to the mirror cover plate, and the control end of the encoder is connected to the encoder handwheel group.

4. The infrared front mirror according to claim 1, characterized in that: The power supply group includes a battery, a battery compartment, a battery cover group, and an electrode group. The battery compartment is located on the side of the mirror body, the electrode group is arranged at the bottom of the battery compartment, the battery is arranged in the battery compartment, and the battery cover group is detachably connected to the battery compartment; the battery cover group and the electrode group are electrically connected to the negative pole and the positive pole of the battery respectively.

5. The infrared front mirror according to claim 1, characterized in that: The focusing group includes an inner distance adjusting wheel, a focusing handwheel, and a focusing screw. The inner distance adjusting wheel is rotatably connected to the mirror body, the focusing handwheel is fixed to the outer side of the inner distance adjusting wheel, a curved groove is provided on the inner side surface of the inner distance adjusting wheel, and a straight groove is provided on the mirror body. One end of the focusing screw is located in the curved groove, and the other end thereof passes through the straight groove and is threadedly connected to the infrared objective lens group.

6. The infrared front mirror according to claim 1, characterized in that: The connecting bracket group comprises a connecting seat, and opening rings which are respectively connected to the eyepiece group and the external white light sight are arranged at two ends of the connecting seat, and a locking mechanism is arranged on the opening ring.

7. The infrared front mirror according to claim 4, characterized in that: The battery compartment is at a certain angle relative to the axis of the mirror body.

8. The infrared front mirror according to claim 1, characterized in that: The scope body is provided with interfaces with certain hole spacing, and the interfaces of the scope body are fixed with standard Picatinny rails.

9. The infrared front mirror according to claim 1, characterized in that: The eyepiece optical system in the eyepiece group includes a first meniscus lens, a double convex lens, a second meniscus lens, a third meniscus lens, a fourth meniscus lens, and a fifth meniscus lens, which are arranged in sequence from the human eye to the display screen, wherein the first meniscus lens and the double convex lens are closely connected to form a cemented lens.

10. The infrared front mirror according to claim 1, characterized in that: The focal length fa of the cemented lens satisfies: 58.71mm<fa<64.89mm; The focal length fb of the second meniscus lens satisfies: 32.34mm<fb<35.75mm; The focal length fc of the third meniscus lens satisfies: 17.80mm<fc<19.67mm; The focal length fd of the fourth meniscus lens satisfies 40.24 mm<fd<44.48 mm; The focal length fe of the fifth meniscus lens satisfies 29.36 mm<fe<32.45 mm; The air gap between the cemented lens and the second meniscus lens is 0.3±0.03mm, the air gap between the second meniscus lens and the third meniscus lens is 2.73±0.03mm, the air gap between the third meniscus lens and the fourth meniscus lens is 3.54±0.03mm, and the air gap between the fourth meniscus lens and the fifth meniscus lens is 0.3±0.03mm.

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