Uniform lighting device for industrial microscopic detection

Abstract

The utility model discloses a uniform lighting device for industrial microscopic detection, which comprises three LED (light-emitting diode) light sources with the size of a light-emitting surface being 1.14 mm * 1.14 mm; the light distribution lens is composed of an annular cylinder and a polygonal cylinder. Three rectangular pyramid-shaped recesses are formed in the bottom of the polygonal cylinder, and the bottom surfaces of the recesses are square; the top surface of the annular cylinder is provided with three aspheric recesses, and the sections of the aspheric recesses are circular; and the LED light source is fixed on the bottom surface of the rectangular pyramid-shaped recess. The lens is designed to be a quarter annular cylinder, compared with a traditional rectangular lens, the size is reduced, the lens is matched with an industrial microscopic detection system packaging space with the diameter smaller than or equal to 50 mm, the lens has the advantages of being large in field angle and high in uniformity on a target surface through the synergistic effect of a bottom rectangular pyramid concave part and a top aspheric concave part, and the optical performance is improved; through the positioning columns and the heat dissipation grooves, the installation offset error is reduced, and the assembly stability is high.

Description

Technical Field

[0001] This invention belongs to the field of non-imaging optical design technology, and particularly relates to a uniform illumination device for industrial microscopic inspection. Background Technology

[0002] In the field of industrial micro-inspection, the illumination cavity space of embedded inspection platforms (such as Automated Optical Inspection (AOI) equipment) typically has a diameter ≤50mm. Current mainstream solutions include: light guide plate solutions require multiple optical films, resulting in a thickness ≥8mm, and an illuminance uniformity of only 41.5% at a distance of 200mm; lens array solutions have a length >30mm, making them unsuitable for miniaturized devices; and bare lamp direct illumination solutions, while small in size, have a light spot uniformity <26%, failing to meet the requirements for chip solder joint inspection (uniformity must be >50%). Existing technologies cannot achieve illumination with >50% illuminance uniformity within a space with a diameter <50mm. The root cause is that conventional Lambertian light source design methods are not suitable for light-emitting surfaces >1mm. 2 This invention addresses the unique challenge posed by non-Lambertian LEDs and proposes an innovative structural solution. Utility Model Content

[0003] The purpose of this invention is to provide a uniform illumination device for industrial microscopic inspection, so as to solve the technical problem that microscopic inspection systems require uniform illumination and have very limited size.

[0004] To solve the above-mentioned technical problems, the specific technical solution of this utility model is as follows:

[0005] In some embodiments of this application, a uniform illumination device for industrial microscopic inspection is provided, comprising:

[0006] Three LED light sources, with a light-emitting surface size of 1.14mm × 1.14mm;

[0007] The light distribution lens is composed of a circular cylinder and a polygonal cylinder;

[0008] The polygonal column has three square pyramidal recesses at its bottom, and the bottom surface of the recesses is square.

[0009] The top surface of the annular cylinder has three aspherical recesses, the cross-section of which is circular;

[0010] The LED light source is fixed to the bottom surface of the quadrangular pyramidal recess.

[0011] In some embodiments of this application, the light-distributing lens is a quarter-ring cylindrical integrated structure made of PMMA.

[0012] In some embodiments of this application, the line connecting the center points of the three aspherical depressions forms an equilateral triangle with a circumcircle diameter of 18±0.2mm.

[0013] In some embodiments of this application, the angle between the lateral slope of the pyramidal recess and the bottom surface is 65°±2°.

[0014] In some embodiments of this application, the height of the annular cylinder is 5±0.2mm, the outer diameter is Φ25±0.5mm, and the inner diameter is Φ10±0.3mm.

[0015] In some embodiments of this application, the maximum depth of the aspherical depression is 1.8±0.1mm, and the surface roughness Ra≤0.05μm.

[0016] In some embodiments of this application, the joint surface of the polygonal cylinder and the annular cylinder is provided with a chamfer structure with a width of 0.5±0.1mm.

[0017] In some embodiments of this application, the distance between the edge of the light-emitting surface of the LED light source and the bottom edge of the concave quadrangular pyramid is 0.15±0.02mm.

[0018] In some embodiments of this application, the top surface of the annular cylinder is provided with three positioning posts with a diameter of Φ1.2±0.1mm and a height of 0.8±0.05mm.

[0019] In some embodiments of this application, the sidewall of the light-distributing lens is provided with heat dissipation grooves with a depth of 0.2±0.05mm and a groove spacing of 2±0.2mm.

[0020] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0021] By designing the lens as a quarter-ring cylinder, its volume is reduced compared to traditional rectangular lenses, making it suitable for packaging spaces in industrial micro-inspection systems with diameters ≤50mm. The lens, through the synergistic effect of the bottom pyramidal concave and the top aspherical concave, produces a large field of view and high uniformity on the target surface, thus improving optical performance. The positioning post and heat dissipation groove not only reduce installation offset errors but also provide high assembly stability. Attached Figure Description

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0023] Figure 1 A schematic diagram of the lens structure provided for an embodiment of this utility model;

[0024] Figure 2 This is a schematic diagram of the assembly structure provided for an embodiment of the present utility model;

[0025] Figure 3 The present invention provides a comparative schematic diagram of candela distribution diagrams of an endoscope illumination system including a light-distributing lens (top) and a bare lamp (bottom) for embodiments of the present invention.

[0026] Figure 4 A comparative schematic diagram of irradiance distribution at a distance of 20mm provided for embodiments of this utility model;

[0027] Figure 5 A comparative schematic diagram of irradiance distribution at a distance of 50mm provided for embodiments of this utility model;

[0028] Figure 6 A comparative schematic diagram of irradiance distribution at a distance of 100mm provided for embodiments of this utility model;

[0029] Figure 7 A schematic diagram showing the comparison of irradiance distribution at a distance of 200mm for embodiments of this utility model. Detailed Implementation

[0030] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0031] To better understand the purpose, structure, and function of this utility model, a more detailed description of this utility model is provided below with reference to the accompanying drawings.

[0032] See appendix Figure 1-7 As shown, according to some embodiments of this application, it includes:

[0033] Three LED light sources 1, with a light-emitting surface size of 1.14mm × 1.14mm;

[0034] The light distribution lens 2 is composed of a circular cylinder and a polygonal cylinder;

[0035] The polygonal column has three square pyramidal recesses at its bottom, and the bottom surface of the recesses is square.

[0036] The top surface of the annular cylinder has three aspherical recesses, the cross-section of which is circular;

[0037] The LED light source 1 is fixed to the bottom surface of the quadrangular pyramidal recess.

[0038] In some embodiments of this application, the light distribution lens 2 is an integrated quarter-ring cylinder structure made of PMMA.

[0039] In some embodiments of this application, the line connecting the center points of the three aspherical depressions forms an equilateral triangle with a circumcircle diameter of 18±0.2mm.

[0040] In some embodiments of this application, the angle between the lateral slope of the pyramidal recess and the bottom surface is 65°±2°.

[0041] In some embodiments of this application, the height of the annular cylinder is 5±0.2mm, the outer diameter is Φ25±0.5mm, and the inner diameter is Φ10±0.3mm.

[0042] In some embodiments of this application, the maximum depth of the aspherical depression is 1.8±0.1mm, and the surface roughness Ra≤0.05μm.

[0043] In some embodiments of this application, the joint surface of the polygonal cylinder and the annular cylinder is provided with a chamfer structure with a width of 0.5±0.1mm.

[0044] In some embodiments of this application, the distance between the edge of the light-emitting surface of the LED light source 1 and the bottom edge of the concave quadrangular pyramid is 0.15±0.02mm.

[0045] In some embodiments of this application, the top surface of the annular cylinder is provided with three positioning posts with a diameter of Φ1.2±0.1mm and a height of 0.8±0.05mm.

[0046] In some embodiments of this application, the sidewall of the light-distributing lens 2 is provided with heat dissipation grooves with a depth of 0.2±0.05mm and a groove spacing of 2±0.2mm.

[0047] When this device is working, the light emitted by the LED light source first reaches the concave side of the square pyramid (the angle between the inclined plane and the base is 65°±2°). Due to the difference in refractive index between air and PMMA, the light is deflected towards the central axis of the lens. The deflected light propagates within the ring cylinder, and when it reaches the side wall of the lens: if the angle of incidence is greater than 42.2°, total internal reflection occurs, and the light is transmitted to the top surface; if it is less than 42.2°, some light escapes due to refraction, resulting in a loss. The light that reaches the top after reflection is affected by the aspherical concave surface (surface parameter: c=0.25mm). -1 Curvature modulation (k = -2.5) results in rays exiting at different angles. Three sets of symmetrically distributed aspherical surfaces cause the light rays to form overlapping circular spots on the target surface.

[0048] Example 1

[0049] A uniform illumination device for industrial microscopic inspection. It comprises two parts: an LED light source 1 and a light-distributing lens 2. The light source 1, model SZ8-Y11-W0-C9-A, has a light-emitting surface size of 1.14mm*1.14mm. Based on the official documentation for light source 1, its luminous characteristics exhibit a non-Lambertian distribution, with each LED having 5 light-emitting surfaces. Given the limited platform size of the microscopic inspection system, the LEDs should be considered as a large-area light source 1. Considering size limitations and luminous efficiency, the light-distributing lens 2 adopts a hybrid design of TIR and quadratic surface, using common PMMA material with a refractive index of 1.4935. The lens as a whole is a quarter-ring cylinder, integrally composed of a circular ring cylinder and a polygonal cylinder. Figure 1 The three LED light sources shown are placed on the bottom surface of the annular column. Figure 1 At the three squares on the front view surface, each square is the base of three pyramidal recesses within a polygonal prism. Light rays enter the entire toroidal lens from the four sides of the pyramids, and after Fresnel refraction and reflection, exit from the three aspherical surfaces of the toroidal lens, converging on the target detection illumination surface to form a uniformly illuminating circular spot. The three aspherical surfaces are formed by the top surface of the toroidal lens (…). Figure 1 The three TIR structures at the rear view are formed by aspherical indentations, and the cross-sections of the three TIR structures in the direction of the top surface of the ring-cylindrical lens are circular. Figure 1 (Three circles on the rear view). The lens structure of this device is compact and lightweight, producing a circular light spot with uniform illumination and clear boundaries on the target illumination surface, making it widely applicable in industrial microscopic inspection lighting systems. Its compact and lightweight design effectively solves the problem of microscopic inspection systems requiring uniform illumination while having very limited size.

[0050] The initial surface structure of the lens of the lighting device was designed and optimized based on Tracepro and Lighttools software. The surface was then modeled into a lens entity in SolidWorks and imported into Lighttools software for ray tracing. To improve the reliability of Lighttools simulation, the total number of ray tracing lines was increased to 14,650,548. Tests were conducted on target surfaces at distances of 20mm, 50mm, 100mm, and 200mm. Figure 2 The image shows the location of the cylindrical lens and LED light source 1 inside the package of the microscopic detection system. The three spherical spaces, each constructed from several circular lines, are the mounting locations for the three LED light sources 1.

[0051] Figure 3A comparison of candela distribution diagrams is provided for the endoscope illumination system with lens 2 (top) and the bare lamp (bottom). The diagrams show that the total light power collected by the illumination system with lens 2 is 98.193W, while the bare lamp collects only 73.129W, resulting in a 34.3% efficiency improvement. Ray tracing was performed on the three lenses using LightTools 8.4.0, with simulations conducted at four distances: 20mm, 50mm, 100mm, and 200mm. It is evident that with lens 2, the minimum field of view is greater than 100°, and the maximum is slightly greater than 120°. At a test distance of 20mm, within a 100° field of view, the radiant flux received by the target surface is 68.257W, with an illuminance uniformity of 56.4%. Simultaneously, at this distance, the bare lamp receives 54.200W of radiant flux, representing a 25.9% efficiency improvement, meeting the design requirements.

[0052] Figure 4 Comparison of irradiance distribution at a distance of 20mm: The top image shows the system with light-distributing lens 2, and the bottom image shows the bare lamp system. At a test distance of 50mm, within a 100° field of view, the radiant flux received by the target surface is 66.241W, and the irradiance uniformity is 61.2%. Meanwhile, at this distance, the bare lamp receives 54.145W of radiant flux, representing a 22.3% increase in efficiency, meeting the design requirements.

[0053] Figure 5 Comparison of irradiance distribution at a distance of 50mm: The top image shows the system with light-distributing lens 2, and the bottom image shows the bare lamp system. At a test distance of 100mm, within a 100° field of view, the radiant flux received by the target surface is 65.535W, and the irradiance uniformity is 62.5%. Meanwhile, at this distance, the bare lamp receives a radiant flux of 54.107W, representing a 21.1% increase in efficiency, meeting the design requirements.

[0054] Figure 6 Comparison of irradiance distribution at a distance of 100mm: The top image shows the system with light-distributing lens 2, and the bottom image shows the bare lamp system. At a test distance of 200mm, within a 100° field of view, the radiant flux received by the target surface is 65.172W, and the irradiance uniformity is 63.2%. Meanwhile, at this distance, the radiant flux received by the bare lamp is 54.084W, representing a 20.5% increase in efficiency, meeting the design requirements.

[0055] Figure 7 Comparison of irradiance distribution at a distance of 200mm: The top image shows the system with light distribution lens 2, and the bottom image shows the bare lamp system.

[0056] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0057] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0058] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0059] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0060] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A uniform illumination device for industrial microscopic inspection, characterized in that, include: Three LED light sources, with a light-emitting surface size of 1.14mm × 1.14mm; The light distribution lens is composed of a circular cylinder and a polygonal cylinder; The polygonal column has three square pyramidal recesses at its bottom, and the bottom surface of the recesses is square. The top surface of the annular cylinder has three aspherical recesses, the cross-section of which is circular; The LED light source is fixed to the bottom surface of the quadrangular pyramidal recess.

2. The uniform illumination device for industrial microscopic detection according to claim 1, characterized in that: The light-distributing lens is a one-piece quarter-ring cylinder structure made of PMMA.

3. The uniform illumination device for industrial microscopic detection according to claim 1, characterized in that: The line connecting the center points of the three aspherical depressions forms an equilateral triangle with a circumcircle diameter of 18±0.2mm.

4. A uniform illumination device for industrial microscopic detection according to claim 1, characterized in that: The angle between the lateral slope and the bottom surface of the pyramidal recess is 65°±2°.

5. The apparatus according to claim 1, characterized in that: The height of the annular cylinder is 5±0.2mm, the outer diameter is Φ25±0.5mm, and the inner diameter is Φ10±0.3mm.

6. A uniform illumination device for industrial microscopic detection according to claim 1, characterized in that: The maximum depth of the aspherical depression is 1.8±0.1mm, and the surface roughness Ra≤0.05μm.

7. A uniform illumination device for industrial microscopic detection according to claim 1, characterized in that: The joint surface between the polygonal cylinder and the annular cylinder is provided with a chamfer structure with a width of 0.5±0.1mm.

8. A uniform illumination device for industrial microscopic detection according to claim 1, characterized in that: The distance between the edge of the light-emitting surface of the LED light source and the bottom edge of the concave square pyramid is 0.15±0.02mm.

9. A uniform illumination device for industrial microscopic detection according to claim 1, characterized in that: The top surface of the annular cylinder is provided with three positioning posts, with a diameter of Φ1.2±0.1mm and a height of 0.8±0.05mm.

10. A uniform illumination device for industrial microscopic detection according to claim 1, characterized in that: The sidewall of the light-distributing lens has heat dissipation grooves with a depth of 0.2±0.05mm and a groove spacing of 2±0.2mm.

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