Anti-reflection and stray light eliminating device suitable for thermal infrared imager

Abstract

The utility model relates to the field of thermal infrared imagers, in particular to an anti-reflection and stray light eliminating device suitable for a thermal infrared imager. Comprising a light shield and a light extinction cup, the light shield is provided with a plurality of light shielding holes arranged in a honeycomb shape, the light extinction cup is in a conical barrel shape, a plurality of light extinction rings are arranged in the light extinction cup, and the light shield is directly connected with a front lens barrel of the thermal imager or the light shield and the light extinction cup are connected to a front lens of the thermal imager after being installed together. According to the utility model, the reflected light of the thermal imager can be effectively reduced, and stray light caused by the sun can be reduced, so that the concealment and the practicability of the thermal imager can be greatly improved.

Description

Technical Field

[0001] The utility model relates to the field of infrared thermal imagers, in particular to an anti-reflection and stray light elimination device suitable for infrared thermal imagers. Background Art

[0002] Infrared thermal imagers are widely used in military and security fields due to their clear imaging capabilities in adverse weather conditions such as rain, snow, and fog, and their ability to operate around the clock. However, in some challenging locations, especially outdoors, sunlight can be reflected by the camera's lens, potentially allowing detection by the enemy. Furthermore, direct sunlight can increase stray light in the system, reducing image quality and impairing scene perception. Currently, anti-reflective devices on the market are primarily designed for riflescopes, creating a pressing need for anti-reflective and stray light reduction devices suitable for infrared thermal imagers. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide an anti-reflection and stray light elimination device for use in an infrared thermal imager, which can effectively reduce the reflection of the thermal imager and eliminate the stray light caused by the sun, thereby greatly increasing the concealment and practicality of the thermal imager.

[0004] In order to solve the technical problem, the technical solution adopted by the utility model is: an anti-reflection and stray light elimination device suitable for an infrared thermal imager, including a light shield and a light extinction cup, the light shield is provided with a plurality of light shielding holes arranged in a honeycomb shape, the light extinction cup is a conical cylinder, and a plurality of light extinction rings are provided inside the light shield, the light shield is directly connected to the front lens barrel of the thermal imager or the light shield and the light extinction cup are installed together and then connected to the front lens of the thermal imager.

[0005] Furthermore, the light-shielding hole is a through hole, the radial cross-section of the light-shielding hole is a regular hexagon, and the side:height ratio of the light-shielding hole is 1:2.

[0006] Furthermore, the extinction ring zone is in the shape of multiple layers of incremental steps.

[0007] Furthermore, the lens hood is made of aluminum alloy and treated with black oxidation process.

[0008] Furthermore, the light shield is circular, and its diameter matches the aperture of the thermal imager. The side of the light shield is provided with threads, and the light shield is connected to the extinction cup through the threads or directly connected to the front barrel of the thermal imager.

[0009] Furthermore, the inner side of the top of the extinction cup is provided with a thread for connecting to a light shield, and the outer side of the bottom of the extinction cup is provided with a thread for connecting to a front lens barrel of an infrared thermal imager.

[0010] Furthermore, stop steps are provided on the threads of the lens hood and the lens, and stop steps are provided on the top inner side and the bottom outer side of the deglare cup. When the threads are connected, the opposite surfaces of the stop steps fit together.

[0011] The present invention has the following beneficial effects: It consists of two parts: an anti-reflection device and a stray light elimination device, which are connected by threads for easy installation and removal. The anti-reflection device has a circular honeycomb-shaped light shield on the front, with a diameter that matches the aperture of the thermal imager. The side of the honeycomb is threaded, allowing it to be connected to the stray light elimination device or directly to the front lens barrel of the thermal imager, making assembly easy. The internal honeycomb structure effectively blocks reflections of sunlight. The stray light elimination device is conical in shape, with an extinction ring inside to eliminate stray light introduced by the anti-reflection device into the imaging optical path. The top inner side is threaded for connection to the anti-reflection device, and the bottom outer side is threaded for connection to the front lens barrel of the infrared thermal imager. The stray light elimination device is easy to remove and can be installed in systems with cooled thermal imagers that are sensitive to the system noise equivalent temperature difference. It can be omitted in systems with uncooled thermal imagers that are less sensitive to the system noise equivalent temperature difference. Another advantage of this device is its ease of installation. It can be quickly and easily installed and removed by simply screwing onto the front lens barrel of the thermal imager. Another advantage is the use of a black oxide finish throughout, effectively reducing solar reflection from the accessory and increasing its concealment. Another advantage is its low cost and light weight, as it is made of aluminum alloy, ensuring minimal cost in the event of damage during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural diagram of the utility model;

[0013] Figure 2 This is a schematic diagram of the top structure of the utility model;

[0014] Figure 3 This is a schematic cross-sectional view of the utility model;

[0015] Figure 4 This is a simulated spot diagram of the utility model installed on a lens;

[0016] Figure 5 This is a simulated relative illumination diagram of the utility model installed on the lens;

[0017] In the picture: 1. Light-shielding hole, 2. Extinction cup, 3. Extinction ring, 4. Thermal imager front barrel, 5. Lens hood. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1

[0020] This embodiment discloses an anti-reflection and stray light elimination device suitable for infrared thermal imagers, such as Figure 1 、 2 As shown in Figure 3, the device comprises a light shield 5 and a light extinction cup 2. The light shield 5 is provided with a plurality of light-shielding holes 1 arranged in a honeycomb shape. The light-shielding holes 1 are through-holes designed according to optical principles into a regular hexagonal structure with a side:height ratio of 1:2. This structure can effectively block the reflection of sunlight from above at the maximum angle, thereby increasing the concealment of the device. The light extinction cup 2 is conical and cylindrical, and is internally provided with a plurality of light extinction rings 3. The light extinction rings 3 are used to reduce stray light within the thermal imager's optical system caused by sunlight, thereby improving the signal-to-noise ratio and thereby enhancing the sensitivity of the thermal imager. The light extinction rings 3 are multi-layered, incrementally stepped, which effectively increases the reflection of stray light. The greater the number of steps, the better the stray light elimination effect.

[0021] In this embodiment, the light shield 5 is made of aluminum alloy and treated with a black oxide process. This not only provides excellent light-shielding performance (low reflectivity), good corrosion resistance, and rust resistance, but also boasts lightweight and low cost. These features make the light shield 5 widely applicable in the fields of anti-glare and gloss reduction for thermal imagers.

[0022] In this embodiment, the light shield 5 is circular, with a diameter that matches the aperture of the thermal imager. Threads are provided on the side of the light shield 5, which connects to the deglare cup 2 or directly to the front lens barrel 4 of the thermal imager. The top inner side of the deglare cup 2 is threaded for connection to the light shield 5, while the bottom outer side of the deglare cup 2 is threaded for connection to the front lens barrel 4 of the infrared thermal imager. Stop steps are provided on the threads of the light shield 5 and the lens. Stop steps are provided on both the top inner side and the bottom outer side of the deglare cup 2. When threaded together, the stop steps mate with each other. When used, the present invention is installed on the front lens barrel 4 of the thermal imager. The two parts of the present invention have a unified interface, allowing them to be used independently or in combination. When used independently, an anti-reflection device can be installed to prevent sunlight reflection, enhancing the concealment of the device. A stray light reduction device can be installed to reduce stray light from the thermal imager caused by sunlight, improving image quality. When used in combination, both anti-reflection and stray light reduction can be achieved. The stray light elimination device is easy to disassemble and can be installed for a system where the cooled thermal imager is relatively sensitive to the system noise equivalent temperature difference, and can be omitted for a system where the uncooled thermal imager is not very sensitive to the system noise equivalent temperature difference.

[0023] Figure 4 、 Figure 5It is a simulated spot diagram and a simulated relative illumination curve of the embodiment of the present invention installed on the lens. It can be found from the figure that installing the present invention in front of the infrared lens does not affect the imaging quality and relative illumination of the thermal imager itself, and it can be used normally.

[0024] The above description is only the basic principle and preferred embodiments of the present invention. Improvements and substitutions made by those skilled in the art based on the present invention fall within the scope of protection of the present invention.

Claims

1. An anti-reflection and stray light elimination device suitable for infrared thermal imagers, characterized by: It includes a light shield and a light extinction cup. The light shield is provided with multiple light-shielding holes arranged in a honeycomb shape. The light extinction cup is a conical cylinder with multiple light extinction rings inside. The light shield is directly connected to the front barrel of the thermal imager or the light shield and the light extinction cup are installed together and then connected to the front lens of the thermal imager.

2. The anti-reflection and stray light elimination device for infrared thermal imagers according to claim 1, characterized in that: The light-shielding hole is a through hole, the radial cross-section of the light-shielding hole is a regular hexagon, and the side:height of the light-shielding hole is 1:

2.

3. The anti-reflection and stray light elimination device for infrared thermal imagers according to claim 1, characterized in that: The extinction ring zone is multi-layered and incremental.

4. The anti-reflection and stray light elimination device for infrared thermal imagers according to claim 1, characterized in that: The lens hood is made of aluminum alloy and treated with black oxide process.

5. The anti-reflection and stray light elimination device for infrared thermal imagers according to claim 1, characterized in that: The lens hood is circular, and its diameter matches the aperture of the thermal imager. There is a thread on the side of the lens hood, which is connected to the extinction cup through the thread or directly connected to the front barrel of the thermal imager.

6. The anti-reflection and stray light elimination device for infrared thermal imagers according to claim 5, characterized in that: The inner side of the top of the extinction cup is threaded for connecting to the sunshade, and the outer side of the bottom of the extinction cup is threaded for connecting to the front barrel of the infrared thermal imager.

7. The anti-reflection and stray light elimination device for infrared thermal imagers according to claim 6, characterized in that: Stop steps are provided on the threads of the lens hood and the lens, and stop steps are provided on the top inner side and the bottom outer side of the deglare cup. When the threads are connected, the opposite surfaces of the stop steps fit together.

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