A folded optical engine imaging device

Abstract

The present application relates to a kind of folded optical machine imaging device, comprising: folding optical machine structure rotation center is located in the ball center of fixed lens;Front lens group, relay lens group is installed in lens barrel, and lens barrel is connected at the interface of one end of light path folding black cavity;Light path folding black cavity is composed of black cavity base and black cavity shell, two interfaces are opened on black cavity shell and are connected with two lenses respectively, and the inside of black cavity shell is treated with extinction.Black cavity base is processed with two elliptic cylinders, and the bevel of elliptic cylinder is mirror surface, and it is 45 ° angle.Black cavity base is treated with extinction except reflecting surface;Rear lens group is installed in lens barrel by means of adhesive or pressure ring, and lens barrel is connected at the outlet of one end of light path folding black cavity by thread or screw.Light is compressed aperture after passing through front lens group, enters rear lens group after passing through black cavity reflection and stray light elimination by relay lens group, and rear lens group converges light and forms image on detector.Folding optical system can move around the ball center of fixed lens.

Description

Technical Field

[0001] This invention relates to a foldable optomechanical imaging device, belonging to the field of optics. Background Technology

[0002] With the development of technology, there are higher requirements for the miniaturization of optical systems. Transmissive optical lenses have the advantages of single-image imaging and small size, and can be designed with a large entrance pupil. However, the stray light that comes with them will further aggravate the impact on image quality. In order to reduce stray light, optical systems need to use secondary imaging systems. Traditional secondary imaging systems are complex in structure due to multiple folds, and are large in size and weight. Alternatively, a folding structure can be used, but such a compact folding structure is difficult to obtain a large field of view. Using a non-folding transmissive secondary imaging system cannot be conveniently applied in small spaces. Summary of the Invention

[0003] The technical problem solved by this invention is that, in order to take into account both miniaturization and secondary imaging advantages, the optical system needs to be folded. This invention provides a folded optomechanical imaging device, which can achieve better detection capabilities within an effective space through folding, eccentricity, and optical path control.

[0004] The solution of the present invention is: a foldable optomechanical imaging device, comprising a fixed lens, a front lens group, a relay lens group, a rear lens group, a first lens barrel, a second lens barrel, and a black cavity;

[0005] A fixed lens is placed in front of the front lens group via a mechanical structure; the rotation center of the folded optomechanical imaging device is located at the center of the fixed lens and can rotate around the center; the front lens group and the relay lens group are installed in the first lens tube, which is installed at the entrance of the black cavity; two mirrors with a 45-degree angle are set in the black cavity, and an aperture is set between the two mirrors; except for the two mirrors, all other parts in the black cavity are treated to extinct light; the rear lens group is installed in the second lens tube, which is installed at the exit of the black cavity; after the light passes through the front lens group, its aperture is compressed, it passes through the relay lens group, and after being reflected and stray light eliminated by the black cavity, it enters the rear lens group, which converges the light rays to form an image on the detector.

[0006] Furthermore, the front lens group, the relay lens group, and the rear lens group all include positive lenses and negative lenses, and each lens group contains at least two lenses.

[0007] Furthermore, the aperture of the front lens group is 1.5 times larger than the maximum aperture of the relay lens group and the rear lens group.

[0008] Furthermore, the front lens group and the relay lens group each contain at least one aspherical lens, and the rear lens group contains at least one aspherical lens, and the aspherical surface of the aspherical lens has an eccentricity or tilt in a predetermined direction.

[0009] Furthermore, the optical axis of the relay lens group is aligned with the entrance center of the black cavity, and the optical axis of the rear lens group is aligned with the exit center of the folded black cavity.

[0010] Furthermore, the black cavity includes a black cavity base and a black cavity housing. The black cavity housing has two interfaces that connect to the first lens barrel and the second lens barrel respectively, and threaded holes are opened on the side. The black cavity base is bonded to the black cavity housing by potting glue. There are adjusting screws around the black cavity housing. Turning the adjusting screws pushes the black cavity base to move in two vertical directions perpendicular to the optical axis of the rear lens group.

[0011] Furthermore, the two reflectors on the black cavity base are cut from cylinders machined on the base, and the two reflective bevels are at a 45° angle, and also at a 45° angle to the machining and positioning surface of the black cavity base; the light rays converged by the front lens group are corrected for aberration by the relay lens group, and the optical axis of the relay lens group is at a 45° angle to the normal of the reflector in the black cavity.

[0012] Furthermore, the diameter of the interface on the black cavity housing that connects to the first lens barrel is equal to the diameter of the intersection circle of the rays emitted from the relay lens group on the plane, and the diameter of the interface that connects to the second lens barrel is equal to the diameter of the intersection circle of the rays emitted from the rear lens group on the plane.

[0013] Furthermore, the first reflecting mirror on the black cavity substrate is the smallest cross-section that does not intercept system light, and the edge of the first reflecting mirror is the aperture stop of the optical system.

[0014] Furthermore, the second reflector on the black cavity substrate is the smallest cross-section that does not intercept system light, and the edge of the second reflector is the aperture stop of the optical system.

[0015] Furthermore, a movable circular or elliptical aperture is placed in the center of the black cavity base plate. The aperture size of the movable circular or elliptical aperture is equal to the minimum beam diameter of the light passing through the two mirrors.

[0016] Furthermore, the optical central axis of the fixed lens is located between the optical central axes of the front lens group and the rear lens group.

[0017] Furthermore, non-imaging light entering the folded optical imaging device is blocked when passing through the entrance and exit of the black cavity, the two mirrors, and the aperture.

[0018] The advantages of this invention compared to the prior art are:

[0019] (1) In the optomechanical imaging device of the present invention, the optical center of the front group optical lens is offset from the optical center of the fixed lens, and the aberration caused by the inconsistency of the optical axis is corrected by the eccentricity and tilt of the aspherical lens, thereby reducing the space occupied by the system while ensuring image quality; by offsetting the optical center of the front group optical lens downward from the optical center of the fixed lens, the centroid of the entire folding optical system is closer to the rotation center of the optomechanical structure, thereby reducing the load on the control system.

[0020] (2) This invention achieves a large entrance pupil and small volume structure by controlling the structural distribution and optical power distribution of the optical lens; it effectively reduces stray light from the optical system by designing two elliptical reflecting surfaces and a movable aperture stop in the black cavity; the integrated design of the reflection system effectively reduces the difficulty of assembly and adjustment; the structural form of this invention is widely applicable to systems with high miniaturization requirements within a limited space, requiring both a large entrance pupil and excellent suppression of stray light.

[0021] (3) This invention utilizes a black cavity with multiple aperture stops to effectively reduce stray light in the system. The mirrors in the black cavity are matched with the beam projection to effectively block stray light. The two mutually perpendicular mirrors are fabricated together with the black cavity, making the entire optomechanical imaging device easy to assemble and adjust. Offset and tilt are introduced into the three lens groups to further correct aberrations caused by the misalignment of the optical axes between the front lens group and the relay lens group. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the optical folding optical-mechanical imaging device of the present invention;

[0023] Figure 2 This is a cross-sectional view of the black cavity device of the present invention;

[0024] Figure 3 This is a cross-sectional view of the optical element of the present invention. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] A folding optomechanical imaging device includes a fixed lens 1, a front lens group 21, a relay lens group 22, a rear lens group 41, a first lens tube 2, a second lens tube 4, and a black cavity 3.

[0027] The fixed lens 1 is placed in front of the front lens group 21 by a mechanical structure; the rotation center of the folded optomechanical imaging device is located at the center 6 of the fixed lens 1 and can rotate around the center 6; the front lens group 21 and the relay lens group 22 are installed in the first lens tube 2, which is installed at the entrance 31 of the black cavity 3; two mirrors with a 45-degree angle are set in the black cavity 3, and an aperture 33 is set between the two mirrors; except for the two mirrors, all other parts in the black cavity 3 are treated to remove light; the rear lens group 41 is installed in the second lens tube 4, which is installed at the exit 35 of the black cavity 3; after the light passes through the front lens group 21, its aperture is compressed, it passes through the relay lens group 22, and after being reflected and stray light removed by the black cavity 3, it enters the rear lens group 41, which converges the light and images it onto the detector 5.

[0028] The front lens group 21, the relay lens group 22 and the rear lens group 41 each include a positive lens and a negative lens, and each lens group contains at least two lenses.

[0029] The aperture of the front lens group 21 is 1.5 times larger than the maximum aperture of the relay lens group 22 and the rear lens group 41.

[0030] The front lens group 21 and the relay lens group 22 each contain at least one aspherical lens, and the rear lens group 41 contains at least one aspherical lens. The aspherical surface of the aspherical lens has an eccentricity or tilt in a predetermined direction.

[0031] The optical axis of the relay lens group 22 is aligned with the center of the entrance 31 of the black cavity 3, and the optical axis of the rear lens group 41 is aligned with the center of the exit 35 of the folded black cavity 3.

[0032] The black cavity 3 includes a black cavity base 37 and a black cavity housing. The black cavity housing has two interfaces that connect to the first lens barrel 2 and the second lens barrel 4 respectively, and has threaded holes on the side. The black cavity base 37 is glued to the black cavity housing by potting glue. There are adjusting screws 36 around the black cavity housing. Turning the adjusting screws 36 pushes the black cavity base 37 to move in two vertical directions perpendicular to the optical axis of the rear lens group.

[0033] The two reflectors on the black cavity base 37 are cut from a cylinder machined on the base. The two reflective bevels are at a 45° angle and at a 45° angle to the machining and positioning surface of the black cavity base 37. The light rays converged by the front lens group 21 are corrected for aberration by the relay lens group 22. The optical axis of the relay lens group 22 is at a 45° angle to the normal of the reflector in the black cavity 3.

[0034] The diameter of the interface on the black cavity housing that connects to the first lens barrel 2 is equal to the diameter of the intersection circle of the rays emitted from the relay lens group 22 on the plane, and the diameter of the interface that connects to the second lens barrel 4 is equal to the diameter of the intersection circle of the rays incident from the rear lens group 41 on the plane.

[0035] The first reflecting mirror 32 on the black cavity base plate 37 is the smallest cross section that does not intercept system light, and the edge of the first reflecting mirror 32 is the aperture stop of the optical system.

[0036] The second reflector 34 on the black cavity base plate 37 is the smallest cross section that does not intercept system light, and the edge of the second reflector 34 is the aperture stop of the optical system.

[0037] A movable circular or elliptical aperture is placed in the center of the black cavity base plate 37. The aperture size of the movable circular or elliptical aperture is equal to the minimum beam diameter of the light passing through the two mirrors.

[0038] The optical center axis of the fixed lens 1 is located between the optical center axes of the front lens group 21 and the rear lens group 41.

[0039] Non-imaging light entering the folded optical imaging device is blocked when passing through the inlet 31 and outlet 35 on the black cavity 3, the two mirrors, and the aperture.

[0040] Example:

[0041] like Figures 1-3 As shown, the folding optical engine imaging device of the present invention includes: a fixed lens 1, a front lens group 21, a relay lens group 22, a rear lens group 41, a first lens barrel 2, a second lens barrel 4, and a black cavity 3.

[0042] The front lens group 21 and the relay lens group 22 are installed in the first lens barrel 2 by adhesive or pressure ring. The first lens barrel 2 is installed at the inlet 31 at one end of the black cavity 3 by threads or screws. The black cavity 3 includes a black cavity base 37 and a black cavity housing. The black cavity housing has an inlet 31 and an outlet 35, which are respectively connected to the first lens barrel 2 and the second lens barrel 4. The black cavity housing has threaded holes on its side, and the system is adjusted by turning the adjusting screw 36. The interior of the black cavity housing is treated with a matte finish. Two elliptical cylinders are machined on the black cavity base 37, with the inclined sides of the elliptical cylinders serving as mirrors, namely the first reflecting mirror 32 and the second reflecting mirror 34, and the included angle between the two reflecting mirrors is 45°. The black cavity base 37 has an aperture 33 in the middle, with a circular or elliptical aperture. Except for the first reflecting mirror 32 and the second reflecting mirror 34, all other parts of the black cavity base 37 are treated with a matte finish. The rear lens group 41 is mounted in the second mirror tube 4 by adhesive or pressure ring. The second mirror tube 4 is connected to the outlet 35 at one end of the black cavity 3 by threads or screws. After passing through the front lens group 21, the light is compressed in diameter, passes through the relay mirror group 22, then through the black cavity inlet 31, and through the first reflecting mirror 32 and the second reflecting mirror 34. After stray light is eliminated, it enters the rear lens group 41, which converges the light rays and images them onto the detector 5. The folding optical system can rotate around the center 6 of the fixed lens 1.

[0043] Specifically, the front lens group 21 includes a first lens 212 (positive lens) and a second lens 211 (negative lens); the relay lens group 22 includes a third lens 222 (negative lens) and a fourth lens 221 (positive lens); the rear lens group 41 includes a fifth lens 411 (negative lens), a sixth lens 412 (negative lens), and a seventh lens 413 (positive lens). In this embodiment, the first lens 212 is made of single-crystal silicon, the second lens 211 is made of IRG209, and the third lens 222 is made of IR... The fourth lens 221 is made of IRG201, the fifth lens 411 is made of single-crystal silicon, the sixth lens 412 is made of calcium fluoride, and the seventh lens 413 is made of IRG209. The specific design parameters of this embodiment are: focal length 31.39mm, entrance pupil size 29.5mm, total length 74mm, 33-line-pair transfer function > 0.7, and 33-line-pair off-axis transfer function > 0.6. This embodiment has a compact structure and good imaging quality, and can be widely used in related fields.

[0044] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A foldable optomechanical imaging device, characterized in that: It includes a fixed lens (1), a front lens group (21), a relay lens group (22), a rear lens group (41), a first lens barrel (2), a second lens barrel (4), and a black cavity (3); The fixed lens (1) is placed in front of the front lens group (21) by a mechanical structure; the rotation center of the folded optomechanical imaging device is located at the center (6) of the fixed lens (1) and can rotate around the center (6); the front lens group (21) and the relay lens group (22) are installed in the first lens tube (2), and the first lens tube (2) is installed at the entrance (31) of the black cavity (3); two mirrors with a 45-degree angle are set in the black cavity (3), and an aperture (33) is set between the two mirrors; except for the two mirrors, all the black cavity (3) is treated to extinct light; the rear lens group (41) is installed in the second lens tube (4), and the second lens tube (4) is installed at the exit (35) of the black cavity (3); after the light passes through the front lens group (21), the aperture is compressed, and after passing through the relay lens group (22), and then after being reflected and stray light eliminated by the black cavity (3), it enters the rear lens group (41), and the rear lens group (41) converges the light to image onto the detector (5); The front lens group (21) consists of a first lens (212) and a second lens (211); the relay lens group (22) consists of a third lens (222) and a fourth lens (221); the rear lens group (41) consists of a fifth lens (411), a sixth lens (412) and a seventh lens (413); The first lens (212) is a positive lens and the second lens (211) is a negative lens; the third lens (222) is a negative lens and the fourth lens (221) is a positive lens; the fifth lens (411) is a negative lens, the sixth lens (412) is a negative lens and the seventh lens (413) is a positive lens; The front lens group (21) and the relay lens group (22) each contain at least one aspherical lens, and the rear lens group (41) contains at least one aspherical lens. The aspherical surface of the aspherical lens has an eccentricity or tilt in a predetermined direction.

2. The foldable optomechanical imaging device according to claim 1, characterized in that, The aperture of the front lens group (21) is 1.5 times larger than the maximum aperture of the relay lens group (22) and the rear lens group (41).

3. A foldable optomechanical imaging device according to claim 1, characterized in that, The optical axis of the relay lens group (22) is aligned with the center of the entrance (31) of the black cavity (3), and the optical axis of the rear lens group (41) is aligned with the center of the exit (35) of the folded black cavity (3).

4. A foldable optomechanical imaging device according to claim 1, characterized in that, The black cavity (3) includes a black cavity base plate (37) and a black cavity housing. The black cavity housing has two interfaces that connect to the first lens tube (2) and the second lens tube (4) respectively, and threaded holes are opened on the side. The black cavity base plate (37) is glued to the black cavity housing by potting glue. There are adjusting screws (36) around the black cavity housing. Tightening the adjusting screws (36) pushes the black cavity base plate (37) to move in two vertical directions perpendicular to the optical axis of the rear lens group.

5. A foldable optomechanical imaging device according to claim 4, characterized in that, The two reflectors on the black cavity base plate (37) are cut from cylinders processed on the base. The two reflective bevels are at a 45° angle and at a 45° angle with the processing and positioning surface of the black cavity base plate (37). The light rays converged by the front lens group (21) are corrected for aberration by the relay lens group (22). The optical axis of the relay lens group (22) is at a 45° angle with the normal of the reflector in the black cavity (3).

6. A foldable optomechanical imaging device according to claim 5, characterized in that, The diameter of the interface on the black cavity housing that connects to the first lens tube (2) is equal to the diameter of the intersection circle of the light rays emitted from the relay lens group (22) on the interface plane on the black cavity housing that connects to the first lens tube (2). The diameter of the interface that connects to the second lens tube (4) is equal to the diameter of the intersection circle of the light rays incident from the rear lens group (41) on the interface plane on the black cavity housing that connects to the second lens tube (4).

7. A foldable optomechanical imaging device according to claim 5, characterized in that, The first reflector (32) on the black cavity base plate (37) is the smallest cross section that does not intercept system light, and the edge of the first reflector (32) is the aperture stop of the optical system.

8. A foldable optomechanical imaging device according to claim 5, characterized in that, The second reflector (34) on the black cavity base plate (37) is the smallest cross section that does not intercept the system light, and the edge of the second reflector (34) is the aperture stop of the optical system.

9. A foldable optomechanical imaging device according to claim 5, characterized in that, The black cavity base plate (37) has a movable circular or elliptical aperture in the center, the aperture of which is equal to the minimum beam diameter of the light passing through the two mirrors.

10. A foldable optomechanical imaging device according to claim 1, characterized in that, The optical center axis of the fixed lens (1) is located between the optical center axes of the front lens group (21) and the rear lens group (41).

11. A foldable optomechanical imaging device according to claim 9, characterized in that, Non-imaging light entering the folded optomechanical imaging device is blocked when passing through the entrance (31) and exit (35) on the black cavity (3), the two mirrors, and the aperture.

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