Dual-spectrum passive optical scanning device

Abstract

The invention discloses a dual-spectrum passive optical scanning device. A light-transmitting cover is arranged at the top end of the detection device, and a detection unit 1 and a detection unit 2 are arranged in the cover. The detection unit 1 is located on the central axis of the rolling support or the support and the shell and is composed of a scanning unit 1, a lens 1 and a detector 1. The detection unit 2 is arranged on the pitching support and is provided with a scanning unit 2, a reflecting mirror 2, a lens 2 and a detector 2. The scanning unit (2) performs pitching scanning along with a pitching motor, and the light beam center line between the reflecting mirror (1) and the reflecting mirror (2) is parallel to a pitching axis. The scanning unit-1 comprises two wedge-shaped lenses which rotate coaxially, light rays within the range of + / -45 degrees can be refracted into the detector 1, and the projection diameter d of related parts of the scanning unit-2 on the wedge-shaped lenses of the scanning unit-1 is smaller than or equal to 40% * D. The device can receive optical signals of at least a hemispherical area, and double-spectrum detection is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical detection, and particularly relates to a dual-spectrum passive optical scanning device. Background Art

[0002] Conventional guiding devices are installed at the head of a moving object to measure motion parameters such as the image size and azimuth angle of a target, generate guidance information, and ultimately guide the moving object to reach a specified target. The guiding device measures the relative position information of the target by receiving the energy radiated or reflected by the target and generates a guidance command, and the performance of the guiding device plays a key role in the successful implementation of guidance.

[0003] Through retrieval, it is found that Chinese authorized invention patent 201911098004.7 ("An optical system with a scanning function") proposes a method of changing the optical path transmission path by inserting or withdrawing a mirror in the optical path of a Cassegrain telescope to achieve the switching between a refractive telescope and a reflective telescope. This design realizes the switching between a large field of view scanning system and a small field of view Cassegrain system. However, the limitation of this scheme is that it cannot achieve the coexistence of large and small fields of view simultaneously.

[0004] Further retrieval reveals that Chinese authorized patent 202210463986.0 ("An optical system with a common aperture and multiple fields of view") describes a method of using the unobstructed edge of the primary mirror of a Cassegrain system to realize a medium-wave infrared large field of view short focal length system, and a method of realizing a small field of view long focal length system by blocking the main optical path of the Cassegrain. This technology realizes the switching by alternately inserting two optical systems into the optical path, but it is limited to the conversion of the large and small fields of view of a single-band light beam and does not support multi-band detection.

[0005] Although the above two schemes can achieve the switching of large and small fields of view, they cannot achieve the simultaneous coexistence of large and small field of view systems. In addition, these schemes also fail to support the function of multi-mode detection.

[0006] The patent application 202410616422.5 of the present inventor proposes a scheme that enables the simultaneous existence of large and small fields of view by using a beam splitting mirror with offset. However, since this scheme requires a relatively wide bandwidth for the optical path, it increases the difficulty of selecting lens materials. At the same time, it is difficult to find materials that meet all optical requirements during the design process to meet the refractive requirements of visible light and medium-wave or long-wave infrared, thus limiting the practical application of this scheme.

[0007] Therefore, the main deficiencies of the prior art are as follows: 1. It is impossible to achieve the simultaneous operation of large and small field of view systems and track two targets simultaneously; 2. Lack the ability to support multi-mode detection; 3. There are significant difficulties in selecting optical materials under bandwidth requirements.

[0008] The description of the above background art is only for explaining the technical background of the present invention and should not be regarded as an admission of the prior art or as something known to those of ordinary skill in the art. Summary of the Invention

[0009] A dual-spectrum passive optical scanning device, comprising: a light-transmitting cover disposed at the top of the scanning device; a detection unit-1 and a detection unit-2 disposed within the light-transmitting cover; The detection unit-1 includes a scanning unit-1, a lens-1, and a detector-1 disposed along the central axis on a rolling bracket or a bracket and a housing; The detection unit-2 includes a scanning unit-2 disposed on a pitching bracket, a mirror-2 disposed on a rolling bracket or a pitching bracket, a lens-2, and a detector-2; The lens of the scanning unit-2 and the mirror-1 are disposed on the pitching bracket, or the mirror-1 is disposed on the pitching bracket and is driven by a pitching motor to perform pitching scanning around the pitching axis; the center line of the light beam between the mirror-1 and the mirror-2 is parallel to and almost coincides with the pitching axis.

[0010] The detection unit-2 can receive optical signals from at least a hemispherical region outside under the drive of a rolling motor and a pitching motor; The scanning unit-1 is composed of two wedge-shaped lenses rotating around the central axis. The two coaxial wedge-shaped lenses cooperate with each other to refract light within an external α range (α = ±45°) through the wedge-shaped lenses and enter the detector-1.

[0011] The diameter of the positive projection of the lens of the scanning unit-2 and the mirror-1, or the mirror-1 on the mirror surface of the wedge-shaped lens (diameter D) of the scanning unit-1 is d, and d ≤ 40% * D; The further limited technical solution of the present invention is: Furthermore, the pitching bracket is connected to the rolling bracket through a pitching motor and is driven by the pitching motor to perform pitching scanning around the pitching axis; the rolling bracket is a hollow columnar shape, is connected to the frame and the housing through a rolling motor, and is driven by the rolling motor to perform rotational scanning around the central axis.

[0012] Furthermore, the mirror-1 of the scanning unit-2 is a semi-transmissive mirror that reflects the light beam in the wavelength band where the lens-2 and the detector-2 are located and transmits the light beam in the wavelength band where the lens-1 and the detector-1 are located.

[0013] Furthermore, the scanning unit-1 is composed of two drive motors, two transmission pairs, two shaft encoders, and two coaxially arranged wedge-shaped lenses.

[0014] Two coaxial wedge-shaped lenses are driven by two motors. The two motors use different combinations of scanning speeds to adjust the beam tilt angle α, where α = a*sin(x*t + φ) + b*sin(y*t + ψ). Where a is the tilt of wedge mirror 1, b is the tilt of wedge mirror 2, x is the rotation speed of wedge mirror 1, y is the rotation speed of wedge mirror 2, φ is the position of wedge mirror 1 at time 0, ψ is the position of wedge mirror 2 at time 0, and t is the time variable.

[0015] When the rotation speeds of the two wedge mirrors are equal, i.e., x = y, and α = a*sin(φ) + b*sin(ψ) is not equal to 0, a circular trajectory is formed.

[0016] If x is not equal to y, the trajectory density depends on the value of x / y, and the time to complete one lap of the lotus-shaped trajectory depends on the smaller value of the speeds x and y, then a lotus-shaped trajectory is formed.

[0017] Furthermore, Detector-1 is a detector in the 3-5μm or 8-12μm infrared band; Detector-2 is a visible light detector.

[0018] Furthermore, α = 45°.

[0019] Furthermore, the optical path of Lens-1 is an infrared optical path with a field of view angle less than 0.5° or less than 2°.

[0020] Advantages of this case: ① It can meet the imaging requirements of two-mode beams in a narrow space similar to a seeker, satisfying both the imaging of visible light in the range of 450nm - 650nm and the imaging requirements of mid-wave infrared (3-5μm) or long-wave infrared (8-12μm), and realizing the detection of the same target using beams of different bands. ② Allocate the infrared band to Detector-1, which reduces the design difficulty, enables existing materials to meet the requirements of the infrared field of view, and meets the requirement that a larger lens diameter is needed for infrared energy detection, thus achieving the goal of coexisting large and small fields of view; allocate the visible light band to Detector-2, utilize the characteristics of a refractive system to process the visible light band and the requirement of a smaller lens diameter, which reduces the design difficulty, also reduces the requirement for the optical system bandwidth, and at the same time has a low requirement for the lens diameter. ③ The scanning unit-1 is driven by a double-wedge mirror to achieve detection within the range of ±45° of the central axis. The scanning unit-2 is driven by a pitch motor and a roll motor to rotate, thus achieving detection in a hemispherical region with a pitch angle of at least ±90°. The two detection units can either simultaneously track and detect a single target or work independently to track and detect different targets. ④Since the infrared optical path of lens - 1 is an infrared optical path with a field of view angle of (0.5 - 2)°, the field of view angle is relatively small, so distant targets can be clearly seen. And because a wedge - shaped mirror is used for scanning, the view is wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1a , Figure 1b , Figure 1c , Figure 1d are schematic diagrams of different combinations of detection unit 1 and detection unit 2; Figure 2a and Figure 2b are schematic diagrams of different α ranges; Figure 3 is a schematic structural diagram of scanning unit 1; Figure 4 is a schematic diagram of the cooperation of coaxial wedge - shaped lenses; Figure 5 is a schematic diagram of a circular trajectory; Figure 6 is a schematic diagram of a lotus - shaped trajectory. SPECIFIC EMBODIMENTS Embodiment 1

[0022] A dual - spectrum passive optical scanning device includes: a light - transmitting cover arranged at the top of the scanning device, a detection unit - 1 and a detection unit - 2 arranged in the light - transmitting cover, a pitch motor, a roll motor, a bracket and a housing. The pitch bracket is connected to the roll bracket by the pitch motor and is driven by the pitch motor to perform pitch scanning around the pitch axis. The roll bracket is a hollow columnar shape, is connected to the frame and the housing by the roll motor, and is driven by the roll motor to perform rotational scanning around the central axis.

[0023] The detection unit - 1 includes a scanning unit - 1, a lens - 1 and a detector - 1 arranged on the roll bracket (refer to Figure 1a and Figure 1c ), or the detection unit - 1 includes a scanning unit - 1, a lens - 1 and a detector - 1 arranged along the central axis on the bracket and the housing (refer to Figure 1b and Figure 1d ); the optical path of the lens - 1 is an infrared optical path with a field of view angle less than (0.5 - 2)°.

[0024] The detection unit - 2 is composed of a scanning unit - 2 arranged on the pitch bracket, a mirror - 2, a lens - 2 and a detector - 2 arranged on the roll bracket. The lens of the scanning unit - 2 and the mirror - 1 are arranged on the pitch bracket (see Figure 1c and Figure 1d ), or the mirror - 1 is arranged on the pitch bracket (see Figure 1a and Figure 1b), and is driven by a pitch motor to perform pitch scanning around the pitch axis. The center line of the light beam between Mirror - 1 and Mirror - 2 is parallel to and almost coincides with the pitch axis. With such a setting, the detection unit - 2 can receive light from at least half of the external spherical region under the drive of the roll motor and the pitch motor; Detector - 1 is an infrared band detector in the 3 - 5μm or 8 - 12μm range; Detector - 2 is a visible light detector.

[0025] Scanning unit - 1 is composed of two wedge - shaped lenses that rotate around the central axis. The two coaxial wedge - shaped mirrors are coordinated such that light in the external α range (α = +45° or α = -45°) enters Detector - 1 through the refraction of the wedge - shaped mirrors; (Refer to Figure 2a and Figure 2b ).

[0026] The lens of Scanning unit - 2 and Mirror - 1, or the diameter of the orthographic projection of Mirror - 1 on the mirror surface of the wedge - shaped lens (diameter D) of Scanning unit - 1 is d, and d ≤ 40% * D; (Refer to Figure 1a ).

[0027] The pitch bracket is connected to the roll bracket by a pitch motor and is driven by the pitch motor to perform pitch scanning around the pitch axis; The roll bracket is a hollow column and is connected to the frame and the housing by a roll motor and is driven by the roll motor to perform rotational scanning around the central axis.

[0028] Refer to Figure 3 , Scanning unit - 1 is composed of two drive motors, two transmission pairs, two shaft encoders, and two coaxial wedge - shaped lenses.

[0029] Refer to Figure 4 , For two coaxial wedge - shaped lenses, driven by two motors, the two motors use different scanning speed combinations to achieve the adjustment of the beam tilt angle α, α = a * sin(x * t + φ) + b * sin(y * t + ψ), where a is the slope of wedge - shaped mirror 1, b is the slope of wedge - shaped mirror 2, x is the rotation speed of wedge - shaped mirror 1, y is the rotation speed of wedge - shaped mirror 2, φ is the position of wedge - shaped mirror 1 at time 0, ψ is the position of wedge - shaped mirror 2 at time 0, and t is the time variable.

[0030] Refer to Figure 5 , When the rotation speeds of the two wedge - shaped mirrors are equal, that is, x = y, and α = a * sin(φ) + b * sin(ψ) and is not equal to 0, a circular trajectory is formed.

[0031] Refer to Figure 6 , If x is not equal to y, the trajectory density depends on the magnitude of x / y, and the time to complete one - circle lotus - shaped trajectory depends on the smaller value of the speeds x and y, then a lotus - shaped trajectory is formed.

Claims

1. A dual-spectrum passive optical scanning device, characterized in that Including: A light-transmitting cover disposed at the top of the scanning device; Detection unit - 1 and detection unit - 2 disposed inside the light-transmitting cover; The detection unit - 1 includes a scanning unit - 1, a lens - 1, and a detector - 1 disposed along the central axis on a rolling bracket or a bracket and a housing; The detection unit - 2 includes a scanning unit - 2 disposed on a pitching bracket, a mirror - 2 disposed on a rolling bracket or a pitching bracket, a lens - 2, and a detector - 2; The lens of the scanning unit - 2 and the mirror - 1, or the mirror - 1 is disposed on the pitching bracket and is driven by a pitching motor to perform pitching scanning around the pitching axis; the center line of the light beam between the mirror - 1 and the mirror - 2 is parallel to and almost coincides with the pitching axis; The detection unit - 2 can receive optical signals in at least a hemispherical region outside under the drive of a rolling motor and a pitching motor; The scanning unit - 1 is composed of two wedge-shaped lenses rotating around the central axis. The two coaxial wedge-shaped lenses cooperate with each other to refract the light within the external α range through the wedge-shaped lenses into the detector - 1, where α is ±45°; The diameter of the positive projection of the lens of the scanning unit - 2 and the mirror - 1, or the mirror - 1 on the mirror surface with a diameter D of the wedge-shaped lens of the scanning unit - 1 is d, and d≤40%*D.

2. The dual-spectrum passive optical scanning device according to claim 1, wherein, The pitching bracket is connected to the rolling bracket through a pitching motor and is driven by the pitching motor to perform pitching scanning around the pitching axis; the rolling bracket is a hollow column and is connected to the frame and the housing through a rolling motor and is driven by the rolling motor to perform rotational scanning around the central axis.

3. The dual-spectrum passive optical scanning device according to claim 1, wherein The mirror - 1 of the scanning unit - 2 is a semi-transmissive mirror that reflects the light beam in the wavelength band of the lens - 2 and the detector - 2 and transmits the light beam in the wavelength band of the lens - 1 and the detector - 1.

4. The dual-spectrum passive optical scanning device according to claim 1, wherein, The scanning unit - 1 is composed of two drive motors, two transmission pairs, two shaft encoders, and two coaxially arranged wedge-shaped lenses; The two coaxial wedge-shaped lenses are wedge lens 1 and wedge lens 2, which are driven by two motors. The two motors use different combinations of scanning speeds to adjust the beam tilt angle α, and α = a sin(x t + φ) + b sin(y t + ψ), where a is the slope of wedge lens 1, b is the slope of wedge lens 2, x is the rotation speed of wedge lens 1, y is the rotation speed of wedge lens 2, φ is the position of wedge lens 1 at time 0, ψ is the position of wedge lens 2 at time 0, and t is the time variable; When the rotational speeds of the two wedge-shaped mirrors are equal, i.e., x = y and α = a sin(φ)+b When sin(ψ) is not equal to 0, a circular trajectory is formed; If x is not equal to y, the track density depends on the magnitude of x / y, and the time to complete one lap of the lotus-shaped track depends on the smaller value of the speeds x and y, then a lotus-shaped track is formed.

5. The dual-spectrum passive optical scanning device according to claim 1, wherein The detector - 1 is an infrared band detector in the range of 3 - 5μm or 8 - 12μm; the detector - 2 is a visible light detector.

6. The dual-spectrum passive optical scanning device according to claim 1, characterized in that α = 45°。 7. The dual-spectrum passive optical scanning device according to claim 1, characterized in that, The optical path of the lens - 1 is an infrared optical path with a field of view angle less than 0.5° or less than 2°.

Images