A thermal lens with a long focal length

Abstract

This invention relates to the field of remote temperature field control. Existing methods for focusing temperature fields involve using thermal metamaterials to directly guide heat from the heat source to the focal point, which does not enable remote control of the temperature field. This invention provides a thermal lens with a long focal length, where the heat absorption / release structural units form a ring or single-ring structure. The power of each heat absorption / release structural unit is determined by the geometric parameters of the thermal lens and the parameters of the heat source. The double-ring and single-ring structures of this invention can achieve temperature field focusing at the same point outside the lens. The heat absorption / release effect is achieved by applying currents of different directions and magnitudes to the thermoelectric semiconductor cooling component. By adjusting the heat absorption / release power, the focal length and focusing temperature of the thermal lens can be changed, allowing the focal point to be a hot or cold spot, thus enabling remote control of the temperature field and solving the problem of the inability to remotely control thermal lenses.

Description

Technical Field

[0001] This invention relates to novel thermal devices, including fields such as remote temperature field control, and more specifically, to a thermal lens with a long focal length. Background Technology

[0002] Optical lenses can easily focus parallel light to a point limited by the diffraction limit, but focusing a diffuse temperature field to a single point is exceptionally difficult. The fundamental reason is the constraint of the second law of thermodynamics, which states that heat cannot spontaneously flow from a low-temperature region to a high-temperature region. Currently, some methods can achieve temperature field focusing, but not by converging or diverging temperature fields. Instead, they use thermal metamaterials to directly guide heat from the heat source to the focal point. The thermal lens involved in this method needs to fill the entire area between the heat source and the focal point, meaning the lens's focal length is zero. Therefore, such lenses cannot achieve remote control of the temperature field. Remote control of the temperature field requires a certain background space between the thermal lens, the heat source, and the focal point, and cannot be directly connected to them. To achieve remote control of the temperature field, a long-focal-length thermal lens is needed. Currently, there is no thermal lens with a long focal length. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention proposes a thermal lens with a long focal length, which solves the problem that existing thermal lenses have short focal lengths and cannot achieve remote control of the temperature of a target point, thus enabling remote control of the temperature field.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A thermal lens with a long focal length ring structure includes an outer ring and an inner ring formed by several thermal absorption / release structural units constituting the boundary of the thermal lens. The inner ring is located inside the outer ring, and the heat source is located inside the inner ring of the ring structure. The absorption / release power of the thermal absorption / release structural units is controlled by the radius R1 of the inner ring and the radius R2 of the outer ring, as well as the position and power of the heat source. The distance between the outer ring of the ring structure thermal lens and the focal point of the temperature field is the focal length.

[0006] Furthermore, the heat absorption / release power of the thermally absorbing / releasing structural unit is calculated using the following formula:

[0007] Inner circle:

[0008] Outer ring: Where Q1 represents the heat absorption / release power of the inner ring, Q2 represents the heat absorption / release power of the outer ring, and the location of the heat source is h. o The power of the heat source is A, and Δθ is the angle subtended by two adjacent structural units about the center of the ring structure. mis the angle between the m-th heat absorption / excitation structure and the x-axis; N is the total number of terms in the Fourier series.

[0009] Furthermore, the focal length f of the thermal lens is calculated using the following formula:

[0010]

[0011] A thermal lens with a long focal length and a circular structure includes a single ring of thermal absorption / release structural units that form the boundary of the thermal lens, and the distance between the single ring of the circular thermal lens and the focal point of the temperature field is the focal length.

[0012] Furthermore, the heat absorption / release power of the thermally absorbing / releasing structural unit is calculated using the following formula:

[0013]

[0014] Furthermore, the heat absorption / release of the heat absorption / release structural unit is achieved by controlling the direction and magnitude of the current applied by the thermoelectric semiconductor cooling component.

[0015] Furthermore, the heat-generating structural unit is implemented using ordinary electric heating elements.

[0016] Furthermore, the number of heat absorption / excitation structural units is no less than twice the total number of terms N in the Fourier series.

[0017] In summary, the invention has the following beneficial effects:

[0018] This invention utilizes several heat absorption / release units to form a long focal length thermal lens with a ring or circular structure. It does not require other complex thermal metamaterials and is simple to implement. The power of the heat absorption / release units can be adjusted by controlling the direction and magnitude of the current. Moreover, the current of the heat absorption / release units is controlled by the circuit system, which changes the parameters of the thermal lens and realizes remote control of the temperature field, thus solving the problem that thermal lenses cannot be remotely controlled. Attached Figure Description

[0019] Figure 1 These are schematic diagrams of two types of thermal lenses.

[0020] Figure 2 Temperature distribution diagram for the remote heating effect of the thermal lens in Example 1.

[0021] Figure 3 This is a temperature simulation distribution diagram of a heat source placed directly at the focal point in Example 1, which is used as a reference when there is no thermal lens.

[0022] Figure 4 Temperature distribution diagram for the remote heating effect of the thermal lens in Example 2.

[0023] In the diagram, 1 is the outer ring, 2 is the inner ring, 3 is the heat source, 4 is the focal point, and 5 is a single ring. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings.

[0025] It should be noted that, for ease of description, the descriptions of direction in the following text are consistent with the directions in the accompanying drawings, but they do not limit the structure of the present invention.

[0026] like Figures 1-4 As shown, this invention discloses a thermal lens with a long focal length and an annular structure. Its features include an outer ring 1 and an inner ring 2 formed by several thermal absorption / release structural units constituting the boundary of the thermal lens. The inner ring 2 is located inside the outer ring 1, and a heat source 3 is located inside the inner ring 2 of the annular structure. The specific position of the heat source can be adjusted as needed, and the heat source 3 cannot be placed at the center of the annular structure. The distance between the heat source 3 and the center of the ring is... To ensure the focal length of the thermal lens is greater than 0, the heat absorption / release power Q of the thermal absorption / release structural unit is controlled by the radius R1 of the inner ring 2 and the radius R2 of the outer ring 1, as well as the position and power of the heat source; the distance between the outer ring 1 of the annular thermal lens and the focal point of the temperature field is the focal length. The heat absorption / release power of each thermal absorption / release structural unit is calculated using the following formula:

[0027] Inner circle:

[0028] Outer ring: Where Q1 represents the heat absorption / release power of the inner ring, Q2 represents the heat absorption / release power of the outer ring, and the location of the heat source is h. o The power of the heat source is A, and Δθ is the angle subtended by two adjacent structural units about the center of the ring structure. m is the angle between the m-th heat absorption / release structure and the x-axis; N is the total number of terms in the Fourier series, and the number of heat absorption / release structure units is no less than twice the total number of terms N in the Fourier series.

[0029] The focal length f of a thermal lens is calculated using the following formula:

[0030]

[0031] The location of heat source 3 can also be determined according to formula 3. Formula (3) can be transformed into: The distance between the heat source 3 and the center of the circle can be calculated using the focal length and the radii of the outer circle 1 and the inner circle 2.

[0032] This invention also discloses a thermal lens with a long focal length circular structure, comprising a single ring 5 of a circular structure formed by several thermal absorption / release structural units constituting the boundary of the thermal lens. In embodiment two, the number of absorption / release structural units in the circular thermal lens is selected to be the same as the number of outer rings in embodiment two. It can be adjusted as needed during use. A single ring of any radius can achieve focusing at a specific focal length by setting different powers of the absorption / release structural units. The distance between the single ring 5 of the circular thermal lens and the focal point of the temperature field is the focal length.

[0033] The heat absorption / release power of the thermally absorbent / exothermic structural unit is calculated using the following formula:

[0034]

[0035] The heat absorption / release structure unit described above achieves heat absorption / release by controlling the direction and magnitude of the current applied by the thermoelectric semiconductor cooling component. The current direction controls heat absorption or release, and the current magnitude controls the amount of heat absorption or release power. The heat release structure unit is implemented using a common electric heating element, and the heat release power is controlled by controlling the current of the electric heating element. Alternatively, a semiconductor cooling component can be used to control the heat release power.

[0036] Implementation Example 1:

[0037] This example presents the two-dimensional simulation results of a thermal lens designed with an inner and outer ring two-layer heat absorption / release unit structure. The inner ring 2 of the thermal lens has a radius of 1m, the outer ring 1 has a radius of 2m, and the point heat source is placed 0.8m away from the center of the ring, with a size of 62.8W / m. In this embodiment, 12 heat absorption / release structures are added to both the inner and outer rings, and the power of each structure is given by formulas (1) and (2) (where N = 6). Figure 2 For the temperature field distribution in the numerical simulation, the entire area (including the background and the interior of the lens) is filled with the background material - copper (thermal conductivity 400 W / K / m). Figure 3 The simulation diagram shows the temperature distribution when a point heat source with a strength of 62.8 W / m is placed at the focal point. It is evident that the thermal lens can focus the temperature field generated by the internal heat source to the focal point. Figure 2 and Figure 3 The temperature field distribution outside the lens is uniform.

[0038] Implementation Example 2:

[0039] This example is a simplification of Example 1, where the heat sources inside the thermal lens and on the inner ring are merged into the heat sources on the outer ring to form a circular thermal lens structure. The power of the inner ring is calculated and merged into the power of the outer ring to form a single-ring structure, thus correcting the power of the outer ring heat source. The modified power of the outer ring heat source is given by formula (4). The outer ring consists of 12 heat absorption / release structures; the temperature distribution diagram from the numerical simulation is shown below. Figure 4 It can be seen that the simplified single-ring thermal lens without internal sources can also achieve the same temperature field distribution outside the lens as in Example 1.

[0040] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A thermal lens of annular structure with long focal length, characterized in that: The outer ring (1) and the inner ring (2) of the annular structure are surrounded by a plurality of thermal absorption / heat release structure units constituting the boundary of the thermal lens, the inner ring (2) is located inside the outer ring (1), the heat source (3) is located inside the inner ring (2) of the annular structure, and the heat source (3) cannot be placed in the center of the annular structure, the absorption / heat release power of the thermal absorption / heat release structure unit is controlled through the radius R1 of the inner ring (2) and the radius R2 of the outer ring (1), and the position and power of the heat source; the distance between the outer ring (1) of the annular structure thermal lens and the temperature field focusing point is the focal length.

2. The thermal lens with a long focal length annular structure according to claim 1, characterized in that: The absorption / heat release power of the thermal absorption / heat release structure unit is calculated by the following formula: Inner ring: (1) Outer ring: (2) Where Q1 represents the heat absorption / release power of the inner ring, Q2 represents the heat absorption / release power of the outer ring, and the location of the heat source is... h o, the power of the heat source is A , The angle subtended by two adjacent structural units with respect to the center of the ring structure. For the first m Individual heat absorption / excitation structure and x The angle subtended by the axis; N Let be the total number of terms in the Fourier series.

3. The thermal lens of claim 1 having a long focal length annular structure, wherein: focal length of the thermal lens f calculated by the equation: （3）。 4. A thermal lens of circular configuration with long focal length, characterized in that: The single ring (5) of the circular structure is surrounded by a plurality of thermal absorption / heat release structure units constituting the boundary of the thermal lens, the single ring (5) of the circular structure thermal lens is the focal length from the temperature field focusing point, the absorption / heat release of the thermal absorption / heat release structure unit is realized by controlling the direction and size of the current of the thermoelectric semiconductor refrigeration assembly, the direction of the current controls the heat absorption or heat release, and the size of the current controls the size of the absorption / heat release power.

5. The thermal lens of claim 4 having a long focal length of circular structure, characterized by: The absorption / heat release power of the thermal absorption / heat release structure unit is calculated by the following formula: （4）。 6. The thermal lens according to any one of claims 1 to 5, wherein: The absorption / heat release of the absorption / heat release structure unit is realized by controlling the direction and size of the current of the thermoelectric semiconductor refrigeration assembly.

7. The thermal lens according to any one of claims 1 to 5, wherein: The heat release structure unit is realized by a common electric heating sheet.

8. The thermal lens according to any one of claims 1 to 5, wherein: The number of the absorption / heat release structure units is not less than 2 times of the total term number N of the Fourier series.

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