Terahertz time-domain spectroscopy lens compact range device

Abstract

The invention relates to the technical field of terahertz time-domain spectroscopy scattering characteristic measurement, in particular to a terahertz time-domain spectroscopy lens compact range device. The terahertz time-domain spectroscopy lens compact range device comprises an off-axis parabolic mirror, a concave lens and a convex lens. Wherein the off-axis parabolic mirror is used for converting wave beams emitted by the transmitting antenna into parallel wave beams. The concave lens is used for diverging the parallel beams. And the convex lens is used for changing the diverged wave beam into a silence area wave beam again. Wherein the focal length and the diameter of the off-axis parabolic mirror are determined according to the divergence angle of the transmitting antenna, the diameters of the off-axis parabolic mirror, the concave lens and the convex lens are sequentially increased, the diameter of the convex lens is larger than that of the quiet zone, and the focal points of the concave lens and the convex lens coincide. The compact range device is a lens compact range, the other implementation mode of the dead zone is achieved, the flexibility of space utilization is improved, the number of needed devices is smaller, and the structure is simple.

Description

Technical Field

[0001] The invention relates to the technical field of terahertz time-domain spectroscopy scattering characteristic measurement, and in particular to a terahertz time-domain spectroscopy lens compact field device. Background Art

[0002] At present, in the terahertz time-domain spectroscopy scattering characteristic measurement system, a parabolic reflector is usually used as the main reflector to form a plane beam to illuminate the target. Due to the limitation of the off-axis angle, the optical path and the device do not make full use of the space, and there are many devices and the optical path is long. Therefore, there is an urgent need for a compact field that can be easily constructed according to the required situation. Summary of the invention

[0003] The purpose of the present invention is to provide a terahertz time-domain spectroscopy lens compact field device to solve the problems that the compact field of the existing terahertz time-domain spectroscopy scattering characteristic measurement system mainly relies on the reflection surface to form a plane wave, thereby resulting in insufficient space utilization of the optical path and devices due to the limitation of the off-axis angle, and there are many devices and the optical path is long.

[0004] In order to achieve the above object, the present invention provides a terahertz time-domain spectroscopy lens compact field device, comprising:

[0005] An off-axis parabolic mirror is used to convert the beam emitted by the transmitting antenna into a parallel beam;

[0006] Concave lens, used to diverge the parallel beam;

[0007] Convex lens, used to convert the divergent beam into a quiet zone beam;

[0008] The focal length and diameter of the off-axis parabolic mirror are determined according to the divergence angle of the transmitting antenna. The diameters of the off-axis parabolic mirror, the concave lens and the convex lens increase in sequence. The diameter of the convex lens is larger than the diameter of the quiet zone, and the focal points of the concave lens and the convex lens coincide.

[0009] Optionally, the concave lens is mounted on a first fixing frame capable of adjusting the pitch and azimuth of the concave lens;

[0010] The convex lens is mounted on a second fixing frame which can adjust the pitch and azimuth of the convex lens.

[0011] Optionally, the terahertz time-domain spectroscopy lens compact field device also includes a displacement platform, which includes a horizontal adjustment part and a longitudinal adjustment part arranged on the horizontal adjustment part, and the first fixed frame and the second fixed frame are installed on the longitudinal adjustment part through a bracket and move with the longitudinal adjustment part.

[0012] Optionally, the distance between the concave lens and the convex lens satisfies the following formula:

[0013]

[0014] Among them, d1 is the diameter of the concave lens, f1 is the focal length of the concave lens, d2 is the diameter of the convex lens, f2 is the focal length of the convex lens, and D is the distance between the concave lens and the convex lens.

[0015] Optionally, the concave lens and the convex lens are made of TPX material.

[0016] Optionally, the diameter of the convex lens is 8% to 12% larger than the diameter of the quiet zone.

[0017] Optionally, the concave lens is a plano-concave lens, and the convex lens is a plano-convex lens.

[0018] The above technical solution of the present invention has the following advantages:

[0019] The terahertz time-domain spectrum lens compact field device provided by the present invention includes an off-axis parabolic mirror, a concave lens and a convex lens. The off-axis parabolic mirror is used to convert the beam emitted by the transmitting antenna into a parallel beam. The concave lens is used to diverge the parallel beam. The convex lens is used to convert the diverged beam into a quiet zone beam again. The focal length and diameter of the off-axis parabolic mirror are determined according to the divergence angle of the transmitting antenna, the diameters of the off-axis parabolic mirror, the concave lens and the convex lens increase successively, the diameter of the convex lens is greater than the diameter of the quiet zone, and the focal points of the concave lens and the convex lens coincide. The compact field device is a lens compact field, which realizes another implementation method of the quiet zone, improves the flexibility of space utilization, requires fewer devices, and has a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings of the present invention are provided for illustrative purposes only, and the proportions and quantities of the components in the drawings may not necessarily be consistent with the actual products.

[0021] Figure 1 It is a structural schematic diagram of a terahertz time-domain spectroscopy lens compact field device in an embodiment of the present invention;

[0022] Figure 2 is a structural schematic diagram of a first fixing frame in an embodiment of the present invention;

[0023] Figure 3 is a structural schematic diagram of a second fixing frame in an embodiment of the present invention;

[0024] Figure 4 It is a schematic structural diagram of a translation platform in an embodiment of the present invention.

[0025] In the figure:

[0026] 1: Off-axis parabolic mirror;

[0027] 2: Concave lens;

[0028] 3: Convex lens;

[0029] 4: first fixed frame;

[0030] 5: second fixing frame;

[0031] 6: Translation stage;

[0032] 61: horizontal adjustment unit;

[0033] 62: longitudinal adjustment part;

[0034] 7: Transmitting antenna. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] like Figure 1 As shown, the terahertz time-domain spectroscopy lens compact field device provided by the embodiment of the present invention includes an off-axis parabolic mirror 1, a concave lens 2, and a convex lens 3. Among them, the off-axis parabolic mirror 1 is used to convert the beam emitted by the transmitting antenna 7 into a parallel beam. The concave lens 2 is used to diverge the parallel beam. The convex lens 3 is used to convert the diverged beam into a parallel beam again, that is, a quiet zone beam. Among them, the focal length and diameter of the off-axis parabolic mirror 1 are determined according to the divergence angle of the transmitting antenna 7 to achieve coverage of the entire range of the beam emitted by the transmitting antenna 7, convert the received beam into a parallel beam, and determine that the beam emitted by the off-axis parabolic mirror 1 is the beam range to be expanded. The diameters of the concave lens 2 and the convex lens 3 are determined by the off-axis parabolic mirror and the quiet zone diameter, respectively, that is, the diameter of the concave lens 2 is larger than the diameter of the off-axis parabolic mirror, and the beam emitted by the off-axis parabolic mirror 1 can be received in the full range. The diameter of the convex lens is larger than the diameter of the concave lens 2 and the diameter of the quiet zone, so as to be able to receive the entire range of beams after the concave lens 2 and generate a quiet zone of a satisfactory size. The focal points of the concave lens 2 and the convex lens 3 coincide. The compact field device is a lens compact field, which realizes another way to realize the quiet zone. The off-axis parabolic mirror 1 converts the beam emitted by the transmitting antenna 7 into a parallel beam, which then diverges after passing through the concave lens 2. The focal point of the concave lens 2 is consistent with that of the convex lens 3, so the divergent beam becomes a parallel beam after passing through the convex lens 3, which is the required quiet zone beam. The compact field device requires fewer devices, has a simple structure, and is more convenient to place in space.

[0037] In order to facilitate the optical path adjustment, in one example, see Figure 2 As shown, the concave lens 2 is mounted on a first fixing frame 4 which can adjust the pitch and azimuth of the concave lens 2. Figure 3 As shown, the convex lens 3 is mounted on a second fixing frame 5 capable of adjusting the pitch and azimuth of the convex lens 3. It should be noted that the first fixing frame 4 and the second fixing frame 5 can be fixed frames with adjustment functions commonly used in existing optical paths, which will not be described in detail.

[0038] In order to further expand the adjustment range and achieve better adjustment of the optical path, in one example, see Figure 4 As shown, the terahertz time-domain spectroscopy lens compact field device also includes a displacement stage 6, which includes a horizontal adjustment portion 61 and a longitudinal adjustment portion 62 arranged on the horizontal adjustment portion 61. The first fixing frame 4 and the second fixing frame 5 are installed on the longitudinal adjustment portion 62 through a bracket and move with the longitudinal adjustment portion 62. By adjusting the horizontal adjustment portion 61, the longitudinal adjustment portion 62 is horizontally moved, thereby realizing the horizontal position adjustment of the first fixing frame 4 and the second fixing frame 5 arranged thereon, and realizing the adjustment of the equal distance between the concave lens 2 and the convex lens 3. The adjustment of the longitudinal adjustment portion 62 can realize the longitudinal position adjustment of the first fixing frame 4 and the second fixing frame 5 arranged thereon.

[0039] It should be noted that the horizontal position and the longitudinal position of the first fixing frame 4 and the second fixing frame 5 can be adjusted respectively, and the adjustment structure is the existing technology, for example, the ball screw structure. The entire translation stage can adopt the existing structure, which will not be repeated here.

[0040] In one example, the distance between the concave lens and the convex lens satisfies the following formula:

[0041]

[0042] Among them, d1 is the diameter of the concave lens, f1 is the focal length of the concave lens, d2 is the diameter of the convex lens, f2 is the focal length of the convex lens, and D is the distance between the concave lens and the convex lens.

[0043] In one example, the diameter of the convex lens 3 is 8% to 12% larger than the diameter of the quiet zone, for example, 9%, 10%, 11%, etc. It should be noted that this range is only a preferred range, and the cost should be reduced as much as possible while meeting the requirements.

[0044] In a specific example, the axial parabolic mirror 1 is selected with a 2-inch aperture and focal length, a 90° off-axis angle and a gold-coated film. The diameters of the concave lens 2 and the convex lens 3 are determined by the off-axis parabolic mirror and the diameter of the quiet zone. The material is TPX, which has a high transmittance to terahertz waves. Concave lens 2 is a plano-concave lens, and convex lens 3 is a plano-convex lens. The diameter of concave lens 2 should be larger than the diameter of the off-axis parabolic mirror, and the diameter of convex lens 3 is 10% larger than the diameter of the quiet zone. The focal points of the concave lens and the convex lens coincide, and the distance between the concave lens and the convex lens satisfies the following:

[0045]

[0046] The off-axis parabolic mirror converts the beam emitted by the transmitting antenna into a parallel beam, which is then diverged after passing through a concave lens. The focus of the concave lens is consistent with that of the convex lens, so the divergent beam becomes a parallel beam after passing through the convex lens, which is the required quiet zone beam.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that not every embodiment contains only one independent technical solution. In the absence of a conflict of solutions, the various technical features mentioned in each embodiment can be combined in any manner to form other implementation methods that can be understood by those skilled in the art.

[0048] In addition, without departing from the scope of the present invention, the technical solutions described in the aforementioned embodiments may be modified, or some of the technical features may be replaced by equivalents, without causing the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A terahertz time-domain spectroscopy lens compact field device, characterized in that: include: An off-axis parabolic mirror is used to convert the beam emitted by the transmitting antenna into a parallel beam; A concave lens, used to diverge the parallel beam; Convex lens, used to convert the divergent beam into a quiet zone beam; The focal length and diameter of the off-axis parabolic mirror are determined according to the divergence angle of the transmitting antenna. The diameters of the off-axis parabolic mirror, the concave lens and the convex lens increase successively. The diameter of the convex lens is larger than the diameter of the quiet zone. The focal points of the concave lens and the convex lens coincide.

2. The terahertz time-domain spectroscopy lens compact field device according to claim 1, characterized in that: The concave lens is mounted on a first fixing frame capable of adjusting the pitch and azimuth of the concave lens; The convex lens is mounted on a second fixing frame which can adjust the pitch and azimuth of the convex lens.

3. The terahertz time-domain spectroscopy lens compact field device according to claim 2, characterized in that: It also includes a translation platform, which includes a horizontal adjustment part and a longitudinal adjustment part arranged on the horizontal adjustment part. The first fixing frame and the second fixing frame are installed on the longitudinal adjustment part through a bracket and move with the longitudinal adjustment part.

4. The terahertz time-domain spectroscopy lens compact field device according to claim 1, characterized in that: The distance between the concave lens and the convex lens satisfies the following formula: Among them, d1 is the diameter of the concave lens, f1 is the focal length of the concave lens, d2 is the diameter of the convex lens, f2 is the focal length of the convex lens, and D is the distance between the concave lens and the convex lens.

5. The terahertz time-domain spectroscopy lens compact field device according to claim 1, characterized in that: The concave lens and the convex lens are made of TPX material.

6. The terahertz time-domain spectroscopy lens compact field device according to claim 1, characterized in that: The diameter of the convex lens is 8% to 12% larger than the diameter of the quiet zone.

7. The terahertz time-domain spectroscopy lens compact field device according to claim 1, characterized in that: The concave lens is a plano-concave lens, and the convex lens is a plano-convex lens.

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