Lens barrel scattered stray light suppression structure

Abstract

A lens barrel scattered stray light suppression structure relates to the technical field of precision optical instruments and is integrated in an optical lens barrel, a multi-stage annular blade assembly is formed by coaxially arranging a plurality of annular blades in the optical axis direction and is arranged on a lens barrel body, and the cutting edge contour line of the multi-stage annular blade assembly is located on the outer side of the maximum view field edge light of an optical lens. The light trapping microstructure is engraved on the inner wall of the lens cone main body between the adjacent annular blades and is coupled with the multi-stage annular blade assembly to form a composite light trap configuration, and the surfaces of the multi-stage annular blade assembly and the light trapping microstructure are coated with extinction coatings. According to the invention, a combined suppression system is constructed from the coupling dimension of geometric angle deflection-composite light trap attenuation-body absorption and conversion, the triple mechanisms cooperate with one another, and synergistic interaction is realized to realize multi-level stray light attenuation, so that the problem of low comprehensive suppression efficiency of dense scattering stray light is solved, and the comprehensive suppression efficiency of the stray light is improved. The stray light suppression method is suitable for stray light suppression requirements in severe task scenes such as space optical loads, high-resolution remote sensing imaging and space-based infrared early warning.

Description

Technical Field

[0001] The present invention relates to the technical field of precision optical instruments, and specifically to a stray light suppression structure for a lens barrel Background Art

[0002] When off-axis light outside the field of view enters the surface of a long and bare lens barrel, it will cause a dense stray light phenomenon. Unsuppressed stray light may mix with imaging light and reach the detector to form background noise, affecting the signal-to-noise ratio and dynamic range of precision optical instruments. In severe cases, distinguishable ghosts may be formed, resulting in the loss of key image information.

[0003] In the prior art, the extinction efficiency of the extinction thread is correlated with factors such as the pitch and tooth profile. The specific parameters of the thread need to be repeatedly optimized through simulation or experiment, and the attenuation effect is limited. The stop ring mainly suppresses stray light within the suppression angle range. When the incident angle deviates from the design threshold, the stray light suppression effect is unstable, and the aperture stop structure placed inside the lens barrel may affect the effective aperture and cause vignetting. The honeycomb light-absorbing layer often sacrifices mechanical structure strength and environmental adaptability for high stray light absorption efficiency, presenting reliability hazards.

[0004] In addition, traditional solutions often rely on a single-dimensional stray light suppression mechanism, which can play a role under certain working conditions. However, when facing dense stray light with multiple incident angles and multi-modal energy characteristics, the comprehensive suppression efficiency has always been unable to break through. Summary of the Invention

[0005] To solve the deficiencies in the background art, the present invention provides a stray light suppression structure for a lens barrel. It uses a multi-stage annular blade assembly to achieve geometric angle deflection for stray light, couples a light-trapping micro-structure to form a composite light trap configuration for attenuation, and the composite light trap configuration relies on an extinction coating for absorption and conversion. The triple mechanism synergistically enhances the multi-level stray light attenuation, significantly improving the stray light suppression effect.

[0006] To achieve the above objective, the present invention adopts the following technical solution: A stray light suppression structure for a lens barrel, the suppression structure is integrated inside the lens barrel of an optical lens, and includes a lens barrel main body, a multi-stage annular blade assembly, and a light-trapping micro-structure. The lens barrel main body selects an empty section of the lens barrel of the optical lens. The multi-stage annular blade assembly is composed of several annular blades arranged coaxially along the optical axis direction and is disposed on the lens barrel main body. The edge contour line thereof is located outside the marginal light rays of the maximum field of view of the optical lens. The light-trapping micro-structure is engraved on the inner wall of the lens barrel main body between adjacent annular blades, and is coupled with the multi-stage annular blade assembly to form a composite light trap configuration. The multi-stage annular blade assembly and the light-trapping micro-structure are coated with an extinction coating.

[0007] Furthermore, the multi-stage annular vane assembly includes at least three stages of annular vanes, which are distributed in an equally spaced or gradient arrangement, and the height of each stage of annular vane is greater than or equal to 2 mm.

[0008] Furthermore, the main body of the lens barrel is provided with enhanced wall thickness.

[0009] Furthermore, the light-trapping micro-structure adopts an axially periodic pattern or a regularly arranged unit array, and its height is less than 2 mm.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] The multi-stage annular vane assembly forms a stray light diaphragm to play a role in geometric angle deflection. Its side walls can physically block these lights to achieve stray light angle deflection, so that the stray light cannot travel along the original propagation direction, but is forced to reflect and scatter. This process realizes the preliminary weakening and guiding of the stray light, and avoids the first-order scattered stray light from irradiating the imaging sensor or film. The multi-stage annular vane assembly is coupled with the light-trapping micro-structure to form a composite light trap configuration. The composite light trap attenuation mechanism is closely connected with the geometric angle deflection mechanism. The stray light after preliminary deflection and guidance undergoes multiple reflections and scatterings between the composite light traps to achieve the purpose of deep attenuation. Throughout the process, the extinction coating always plays the role of body absorption and conversion, converting light energy into heat energy or other forms of energy. The composite light trap structure extends the propagation path of the stray light, provides conditions for body absorption and conversion, and further increases the probability and degree of stray light energy attenuation. The present invention constructs a joint suppression system from the coupling dimension of "geometric angle deflection - composite light trap attenuation - body absorption and conversion", forms a complete suppression chain from macroscopic optical path regulation to microscopic energy conversion, and the triple mechanisms cooperate with each other and synergistically enhance to achieve multi-level stray light attenuation, solve the problem of low comprehensive suppression efficiency of dense scattered stray light, and significantly improve the stray light suppression effect. Description of the Drawings

[0012] Figure 1 is a schematic diagram of an optical system applying the stray light suppression structure of the lens barrel of the present invention;

[0013] Figure 2 is a tracing diagram of the dense scattered stray light phenomenon of an optical system without a suppression structure.

[0014] In the figure: 100, suppression structure section; 200, light shield; 300, optical lens; 400, detector; 500, off-axis stray light source outside the field of view; 110, main body of the lens barrel; 111, multi-stage annular vane assembly; 112, light-trapping micro-structure. Detailed Embodiments

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0016] The mirror barrel stray light suppression structure of the present invention is applied to a transmissive optical system in the visible light band for description. With reference to Figure 1 As shown, the optical system includes a light shield 200, an optical lens 300, and a detector 400. The field of view angle of the optical lens 300 is ±5°. The mirror barrel stray light suppression structure of the present invention is integrally provided with the optical lens 300 to form a suppression structure section 100. The suppression structure section 100 includes a mirror barrel body 110, a multi-stage annular blade assembly 111, and a light trapping microstructure 112. The mirror barrel body 110 is selected from an empty section of the mirror barrel of the optical lens 300. The multi-stage annular blade assembly 111 is composed of a plurality of annular blades arranged coaxially along the optical axis direction inside the mirror barrel body 110. The edge contour line thereof is located outside the outermost marginal ray of the maximum field of view of the optical lens 300. The light trapping microstructure 112 is engraved on the inner wall of the mirror barrel body 110 between adjacent annular blades, and is coupled with the multi-stage annular blade assembly 111 to form a composite light trap configuration. The surfaces of the multi-stage annular blade assembly 111 and the light trapping microstructure 112 are coated with an extinction coating, and the absorption rate of the extinction coating can be 95%.

[0017] In an optical system without the suppression structure of the present invention, with reference to Figure 2 As shown, when the off-axis angle of the off-axis stray light source 500 outside the field of view is in the range of 8° to 14°, the angle of the stray light incident on the optical system gradually increases, and the boundary point of the opto-mechanical system reached by the light gradually moves to the left. Specifically, the boundary point starts from the edge of the seventh lens inside the optical lens 300 and gradually moves to the edge of the sixth lens. During this process, the mirror barrel body 110 connecting these two lenses will inevitably be illuminated, and the aspect ratio of the mirror barrel body 110 is greater than 0.5. At this time, the inner wall of the mirror barrel body 110 is both the illuminated surface and the key surface that can be seen by the detector 400. Therefore, there is a potential first-order stray light path: off-axis stray light source 500 outside the field of view - front lens group of the optical lens 300 - inner wall of the mirror barrel body 110 - rear lens group of the optical lens 300 - detector 400. When stray light sources with multiple incident angles act simultaneously, dense scattered stray light appears on the surface of the long and bare mirror barrel, thereby affecting the imaging quality.

[0018] When the stray light suppression structure of the lens barrel of the present invention is applied to an optical system, after off-axis light passes through the front lens group and reaches the suppression structure section 100, the multi-stage annular vane assembly 111 forms a stray light diaphragm to play a role in geometric angle deflection. Its side walls can physically block these light rays to achieve the angular deflection of stray light, so that the stray light cannot travel along the original propagation direction but is forced to be reflected and scattered. This process realizes the preliminary weakening and guiding of stray light, avoiding the first-order scattered stray light from irradiating the imaging sensor or film. The multi-stage annular vane assembly 111 is coupled with the light-trapping micro-structure 112 to form a composite light trap configuration. The attenuation mechanism of the composite light trap is closely connected with the geometric angle deflection mechanism. The stray light after preliminary deflection and guidance undergoes multiple reflections and scatterings among the composite light traps to achieve the purpose of deep attenuation. Throughout the process, the extinction coating always plays the role of body absorption and conversion, converting light energy into heat energy or other forms of energy. The composite light trap structure extends the propagation path of stray light, provides conditions for body absorption and conversion, and further increases the probability and degree of stray light energy attenuation.

[0019] Figure 1 In the optical system shown, the multi-stage annular vane assembly 111 includes at least three stages of annular vanes and is distributed in an equidistant or gradient arrangement. The height of each stage of annular vane is greater than or equal to 2 mm, so as to ensure that the annular vane does not interfere with the imaging light path but only affects the stray light path, enabling the optical system to maintain its original imaging performance, effectively intercept or attenuate stray light, reduce the non-desired light rays in the optical system, and reduce the adverse effects that may be caused by stray light.

[0020] Figure 1 In the optical system shown, the light-trapping micro-structure 112 adopts an axially periodic texture or a regularly arranged unit array, and the type can be an extinction thread, a honeycomb-shaped light-absorbing cavity, a polygonal groove or others. Its height is less than 2 mm, so as to ensure that the scattered stray light is effectively attenuated when entering the composite light trap and increase the surface area of the stray light absorption surface.

[0021] Figure 1 In the optical system shown, the lens barrel body 110 adopts a wall thickness strengthening setting, which can strengthen the bases of the multi-stage annular vane assembly 111 and the light-trapping micro-structure 112, form a constraint relationship with their specific design parameters, enhance the impact resistance performance, improve the overall structural stability and durability, reduce the maintenance requirements, and ensure the mechanical reliability.

[0022] The stray light suppression structure of the lens barrel of the present invention is different from the single suppression mechanism in the traditional solution. It constructs a joint suppression system from the coupling dimension of "geometric angle deflection - compound optical trap attenuation - body absorption conversion", forming a complete suppression chain from macroscopic optical path regulation to microscopic energy conversion. These three mechanisms are not simply superimposed, but an organic whole, cooperating with each other and synergistically enhancing to achieve multi-level stray light attenuation, solving the problem of low comprehensive suppression efficiency of dense scattered stray light. In particular, it improves the attenuation effect of scattered stray light with multi-incidence angle and multi-modal energy characteristics caused by off-axis light incident on the surface of a long and bare lens barrel outside the field of view, effectively improving the imaging quality of the optical system, and is applicable to the stray light suppression requirements in harsh mission scenarios such as space optical payloads, high-resolution remote sensing imaging, and space-based infrared early warning.

[0023] In terms of design, the present invention allows users to customize the lens barrel structure according to specific optical path conditions, flexibly adjust the number of annular blades, layout of the multi-stage annular blade assembly 111, and the selection and height of the light-trapping microstructures 112, and meet special system requirements through personalized solutions, with a high degree of design freedom.

[0024] In terms of processing, the manufacturing process of the multi-stage annular blade assembly 111 can draw on the mature process of the inner baffle ring of the light shield. The lens barrel body 110, the multi-stage annular blade assembly 111, and the light-trapping microstructures 112 can be processed by an integrated molding method. For the high-precision requirements of the light-trapping microstructures 112, laser etching technology can also be selected.

[0025] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent conditions of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed claims.

[0026] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A structure for suppressing stray light scattered by a lens barrel, characterized in that: The suppression structure is integrated inside the lens barrel of the optical lens (300), and comprises a lens barrel body (110), a multi-stage annular blade assembly (111), and a light-trapping microstructure (112); the lens barrel body (110) is selected from an empty section of the lens barrel of the optical lens (300); the multi-stage annular blade assembly (111) is composed of a plurality of annular blades coaxially arranged along an optical axis direction and arranged on the lens barrel body (110); the edge contour line of the multi-stage annular blade assembly (111) is located outside the maximum field of view edge light of the optical lens (300); the light-trapping microstructure (112) is engraved on the inner wall of the lens barrel body (110) between adjacent annular blades and coupled with the multi-stage annular blade assembly (111) to form a composite light trap configuration; the surfaces of the multi-stage annular blade assembly (111) and the light-trapping microstructure (112) are covered with a matte coating.

2. The lens barrel scattered stray light suppression structure according to claim 1, characterized in that: The multi-stage annular blade assembly (111) comprises at least three stages of annular blades, which are arranged in an equidistant or gradient manner, and the height of each stage of the annular blades is greater than or equal to 2 mm.

3. A lens barrel scattered stray light suppression structure according to claim 1 or 2, characterized in that: The lens barrel body (110) is provided with a reinforced wall thickness.

4. The structure for suppressing stray light from a lens barrel according to claim 3, characterized in that: The light trapping microstructure (112) adopts axial periodic patterns or regularly arranged unit arrays, and its height is less than 2 mm.

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