Optical component, lighting system and imaging system

Abstract

The present invention relates to the fields of defect detection technology and optical technology, and in particular to an optical component, an illumination system and an imaging system. When detecting the three-dimensional structure of an object to be detected, an LED light source plus an illumination lens group can be used to replace a common LED light source or a collimated laser light source, thereby greatly reducing the detection cost. In addition, a second divergence angle β of light reaching the surface of the three-dimensional structure of the object to be detected is greatly reduced compared with a first divergence angle α emitted from the light source. When used for defect detection of three-dimensional contact lenses, the system can meet the requirements for detecting tiny defects of contact lenses, effectively improve the defect detection capability of contact lenses, and has strong practicality.

Description

Technical Field

[0001] The present invention relates to the technical field of defect detection and the technical field of optics, and in particular to an optical component, an illumination system and an imaging system. Background Art

[0002] At present, in the lighting system of contact lens defect detection equipment, LEDs of a certain area and arrangement are usually used as lighting sources, where the LED arrangement can be matrix-type or concentric ring-type; in order to adapt to the three-dimensional structural characteristics of contact lenses, the concentric ring-type LED arrangement also supports different installation angles of LEDs in different rings to achieve regional lighting of contact lenses. In order to make the light intensity evenly distributed within a certain spatial range, a light diffusion plate is often configured after the LED lighting source.

[0003] At present, even LED products with good divergence angles can hardly have divergence angles lower than 10 degrees. Considering the diffusion characteristics of the light diffusion plate, after the light beam generated by the lighting system of the previous contact lens defect detection equipment reaches the lens surface, although the light intensity can be almost evenly distributed at different spatial positions, it is difficult to make the divergence angle of the lighting beam smaller. This limits the recognition accuracy and detection ability of some small defects or transparent defects when performing transmission-type bright field imaging in the previous contact lens defect detection process.

[0004] It is easy to understand that for transparent objects with planar structures, when the divergence angle of the transmitted light beam is small, such as when a collimated laser beam is used for incident light in extreme cases, slight defects on the planar transparent object will cause obvious deflection of the incident light beam, thus being presented during the image acquisition process. When an LED light source with a larger divergence angle is used for illumination, the degree of visualization will be greatly reduced, which is specifically reflected in the decrease in the contrast of the defects that can be visualized, and even slight defects are difficult to visualize. However, collimated laser light sources are rarely used in contact lens defect detection systems due to factors such as complexity, service life, cost, and low degree of adaptation to lenses with different degrees. On the other hand, although LED light sources with low cost, stable performance, and high cost-effectiveness in detection are highly favored in contact lens defect detection systems, they cannot meet the requirements for detecting tiny defects. Based on the shortcomings of existing lighting systems, it is urgent to provide a solution. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides an optical component, an illumination system and an imaging system, which can effectively reduce the divergence angle of light from a light source when it reaches the surface of the three-dimensional structure of the object to be tested, and modulate it to the required intensity, thereby improving the contact lens defect detection capability.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides an optical component, comprising a first lens group, an aperture stop, a filter element and a second lens group arranged along an optical axis direction; light rays with a first divergence angle α emitted by a light source are angle-bent after passing through the first lens group; when the angle-bent light rays pass through the aperture stop and the filter element, the aperture stop and the filter element modulate the angle and intensity of the light rays, so as to limit and reduce the divergence angle of the light rays and modulate the intensity of the light rays with different divergence angles to a desired intensity;

[0008] The light after angle and intensity modulated is deflected again by the second lens group, so that when the light reaches the surface of the three-dimensional structure of the object to be measured, the illumination angles at different spatial positions are different and the light intensity is the same, and the second divergence angle β of the illumination light at each position of the three-dimensional structure of the object to be measured is smaller than the first divergence angle α.

[0009] Further, the first lens group includes a first light-incoming lens and a first light-outgoing lens; the light-incoming surface and the light-outgoing surface of the first light-incoming lens are both convex structures; the light-incoming surface of the first light-outgoing lens is a concave structure, and the light-outgoing surface of the first light-outgoing lens is a flat or convex structure; the air gap between the first light-incoming lens and the first light-outgoing lens is 0 or a value greater than 0;

[0010] Alternatively, the first lens group includes a single lens or a double cemented achromatic lens, the light incident surface of the first lens group is a convex structure, and the light exit surface of the first lens group is a plane or convex structure.

[0011] Further, the second lens group includes a second light-incoming lens and a second light-outgoing lens; the light-incoming surface of the second light-incoming lens is a plane or convex structure, and the light-outgoing surface of the second light-incoming lens is a concave structure; the light-incoming surface and the light-outgoing surface of the second light-outgoing lens are both convex structures; the air gap between the second light-incoming lens and the second light-outgoing lens is 0 or a value greater than 0;

[0012] Alternatively, the second lens group includes a single lens or a double cemented achromatic lens, the light incident surface of the second lens group is a plane or convex structure, and the light exit surface of the second lens group is a convex structure.

[0013] Preferably, the equivalent focal length f1 of the first lens group is a positive value; the light source is located before the light entrance surface of the first lens group, and the distance l1 to the light entrance surface is greater than the equivalent focal length f1 of the first lens group; the distance l2 between the image plane of the light source formed by the first lens group and the light exit surface of the first lens group satisfies or approximately satisfies 1 / l1+1 / l2=1 / f1;

[0014] The distance l1 between the light source and the light-entry surface of the first lens group can be continuously adjusted under the premise of being greater than the equivalent focal length f1 of the first lens group, so as to limit the maximum divergence angle of the light reaching the surface of the three-dimensional structure of the object to be measured;

[0015] The position of the first lens group, the aperture stop and the filter element as a whole is adjusted as the distance l1 between the light source and the light incident surface of the first lens group is adjusted, thereby improving the contact lens defect detection capability and achieving the best detection effect.

[0016] Preferably, the equivalent focal length f2 of the second lens group is a positive value, the image plane of the light source formed by the first lens group is located before the light incident surface of the second lens group, the image plane of the light source formed by the first lens group is located at the front focal plane or near the front focal plane of the second lens group, and the distance from the image plane of the light source formed by the first lens group to the light incident surface of the second lens group is or is approximately the equivalent focal length f2 of the second lens group, so as to ensure that the shape of the wavefront of the outgoing light beam is as close as possible to the curved surface shape of the three-dimensional structure of the object to be tested, thereby improving the defect detection capability of contact lenses and achieving the best detection effect.

[0017] Furthermore, the aperture diaphragm adopts a variable diaphragm, the variable diaphragm is provided with an opening, and the variable diaphragm is driven by an diaphragm driving device connected to drive the opening size of the variable diaphragm.

[0018] Furthermore, the filter element includes a filter group turntable, a plurality of filters with different transmittances arranged on the filter group turntable, and a filter driving device connected to the filter group turntable, wherein the filter driving device is used to drive the filter group turntable to rotate so that the filter with the required transmittance is located in the light path.

[0019] The present invention also provides a lighting system, comprising the above optical component; and also comprising a plurality of LED light sources arranged in an array and a light diffuser for converting the point light sources of the LED light sources into a surface light source, wherein the light emitted by the light diffuser passes through a first lens group.

[0020] The present invention also provides an imaging system, comprising the above-mentioned lighting system; and also comprising a transparent carrier for placing the three-dimensional structure of the object to be measured, and an image acquisition device for acquiring images of the three-dimensional structure of the object to be measured.

[0021] Furthermore, it also includes a first driving device for driving the LED light source and the light diffusion plate to move as a whole, and a second driving device for driving the LED light source, the light diffusion plate, the first lens group, the filter element, and the aperture stop to move as a whole.

[0022] Beneficial effects of the present invention:

[0023] The present invention relates to the fields of defect detection technology and optical technology, and in particular to an optical component, an illumination system and an imaging system. When detecting the three-dimensional structure of an object to be detected, an LED light source plus an illumination lens group can be used to replace a common LED light source or a collimated laser light source, thereby greatly reducing the detection cost. In addition, a second divergence angle β of light reaching the surface of the three-dimensional structure of the object to be detected is greatly reduced compared with a first divergence angle α emitted from the light source. When used for defect detection of three-dimensional contact lenses, the system can meet the requirements for detecting tiny defects of contact lenses, effectively improve the defect detection capability of contact lenses, and has strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a simplified structural schematic diagram of the optical component and the lighting system of the present invention.

[0025] Figure 2 It is a schematic diagram of the optical path structure of the optical component and the lighting system described in the present invention.

[0026] Figure 3 It is a simplified structural schematic diagram of the aperture stop described in the present invention.

[0027] Figure 4 It is a simplified structural schematic diagram of the filter element described in the present invention.

[0028] Figure 5 It is a simplified structural schematic diagram of the optical component described in the present invention.

[0029] Figure 6 It is a simplified structural schematic diagram of the imaging system according to the present invention.

[0030] Figure 7 It is a schematic diagram of a defective contact lens in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with the embodiments and drawings, and the contents mentioned in the embodiments are not intended to limit the present invention. The present invention is described in detail below in conjunction with the drawings.

[0032] The present invention is applicable to the detection of contact lenses, and is also applicable to the defect detection of products such as artificial lenses, OK lenses, and glass lenses, and can be extended to the defect detection of other transparent materials with three-dimensional structures. In this embodiment, the object to be detected is a contact lens, and the three-dimensional structure 5 of the object to be detected is illustrated by a three-dimensional lens of a contact lens.

[0033] refer to Figures 1 to 4 As shown, the present invention provides an optical component, comprising a first lens group 1, an aperture stop 2, a filter element 3 and a second lens group 4 arranged along an optical axis.

[0034] In practical application, the optical component can be arranged between the light source 6 and the three-dimensional structure 5 of the object to be measured, and the light source 6 emits a light with a first divergence angle α, which is angle-bent after passing through the first lens group 1;

[0035] When the light after angle deflection passes through the aperture stop 2 and the filter element 3, the aperture stop 2 and the filter element 3 modulate the angle and intensity of the light, so as to limit and reduce the divergence angle of the light and modulate the intensity of the light with different divergence angles to the required intensity; specifically, the aperture stop 2 located near the image focal plane of the first lens group 1 reduces the first divergence angle α of the light beam emitted from any point of the light source 6; the filter element 3 with the function of spatial light intensity modulation adjusts the light energy of the aperture stop 2 opening;

[0036] The light after angle and intensity modulation is deflected again after passing through the second lens group 4, so that when the light reaches the surface of the three-dimensional structure 5 of the object to be measured, the illumination angles at different spatial positions are different and the illumination intensity is the same; the light propagation direction at each spatial position is consistent with or close to the normal direction of the surface of the three-dimensional structure 5 of the object to be measured, and the second divergence angle β of the illumination light at each position of the three-dimensional structure 5 of the object to be measured is smaller than the first divergence angle α, so that the second divergence angle β is greatly reduced compared with the first divergence angle α emitted from the light source 6, so that the final imaging pattern is evenly distributed, thereby improving the contact lens defect detection capability.

[0037] This optical component is particularly suitable for LED light sources with low cost, stable performance and high cost-effectiveness in detection. When detecting the three-dimensional structure 5 of the object to be detected, an LED light source plus an illumination lens group can be used to replace an ordinary LED light source or a collimated laser light source, thereby greatly reducing the detection cost. In addition, the second divergence angle β of the light reaching the surface of the three-dimensional structure 5 of the object to be detected is greatly reduced compared with the first divergence angle α emitted from the light source. When used for defect detection of three-dimensional contact lenses, it can meet the requirements for detecting tiny defects in contact lenses, effectively improve the defect detection capability of contact lenses, and has strong practicality.

[0038] In this embodiment, the first lens group 1 includes a first light-inlet lens 11 and a first light-outlet lens 12; the light-inlet surface and the light-outlet surface of the first light-inlet lens 11 are both convex structures; the light-inlet surface of the first light-outlet lens 12 is a concave structure, and the light-outlet surface of the first light-outlet lens 12 is a plane or a convex structure; the air gap between the first light-inlet lens 11 and the first light-outlet lens 12 is 0 or a value greater than 0; or the first lens group 1 includes a single lens or a double-cemented achromatic lens, the light-inlet surface of the first lens group 1 is a convex structure, and the light-outlet surface of the first lens group 1 is a plane or a convex structure.

[0039] In this embodiment, the second lens group 4 includes a second light-inlet lens 41 and a second light-outlet lens 42; the light-inlet surface of the second light-inlet lens 41 is a plane or a convex structure, and the light-outlet surface of the second light-inlet lens 41 is a concave structure; the light-inlet surface and the light-outlet surface of the second light-outlet lens 42 are both convex structures; the air gap between the second light-inlet lens 41 and the second light-outlet lens 42 is 0 or a value greater than 0; or the second lens group 4 includes a single lens or a double-cemented achromatic lens, the light-inlet surface of the second lens group 4 is a plane or a convex structure, and the light-outlet surface of the second lens group 4 is a convex structure.

[0040] In this embodiment, the equivalent focal length f1 of the first lens group 1 is a positive value; the light source 6 is located before the light incident surface of the first lens group 1, and the distance l1 to the light incident surface is greater than the equivalent focal length f1 of the first lens group 1; the distance l2 between the image plane of the light source 6 formed by the first lens group 1 and the light exit surface of the first lens group 1 satisfies or approximately satisfies 1 / l1+1 / l2=1 / f1; the distance l1 between the light source 6 and the light incident surface of the first lens group 1 can be continuously adjusted on the premise that it is greater than the equivalent focal length f1 of the first lens group 1, so as to limit the maximum divergence angle of the light reaching the surface of the three-dimensional structure 5 of the object to be measured; the first lens group 1, the aperture stop 2 and the filter element 3 as a whole, their position is adjusted as the distance l1 between the light source 6 and the light incident surface of the first lens group 1 is adjusted, and when used for defect detection of three-dimensional contact lenses, the defect detection capability of contact lenses is improved to achieve the best detection effect.

[0041] In this embodiment, the equivalent focal length f2 of the second lens group 4 is a positive value, the image plane of the light source 6 formed by the first lens group 1 is located before the light incident surface of the second lens group 4, the image plane of the light source 6 formed by the first lens group 1 is located at the front focal plane or near the front focal plane of the second lens group 4, and the distance from the image plane of the light source 6 formed by the first lens group 1 to the light incident surface of the second lens group 4 is or is approximately the equivalent focal length f2 of the second lens group 4; the distance from the image plane of the light source 6 formed by the first lens group 1 to the light incident surface of the second lens group 4 is equal to or may be slightly greater than or slightly less than the equivalent focal length f2 of the second lens group 4, so as to ensure that the shape of the wavefront of the outgoing light beam is as close to the curved surface shape of the three-dimensional structure 5 of the object to be tested as possible, and when used for defect detection of three-dimensional contact lenses, the defect detection capability of contact lenses is improved to achieve the best detection effect.

[0042] Please refer to Figure 3 As shown, in this embodiment, the aperture diaphragm 2 adopts a variable diaphragm, which is provided with an opening 21, and the variable diaphragm driving device 22 for driving the opening size of the variable diaphragm is connected. Specifically, the aperture diaphragm 2 is provided with a circular opening and / or an annular opening. Preferably, the size of the variable diaphragm can vary between 1mm-15mm.

[0043] Please refer to Figure 4 As shown, in this embodiment, the filter element 3 includes a filter set rotating disk 31, a plurality of filters 32 with different transmittances arranged on the filter set rotating disk 31, and a filter driving device 33 drivingly connected to the filter set rotating disk 31, and the filter driving device 33 is used to drive the filter set rotating disk 31 to rotate so that the filter 32 with the required transmittance is located in the light path. Specifically, the filter 32 can be divided into a circular area and an annular area, and the two areas have different transmittances, and a plurality of filter circular / annular area transmittance combinations can be selected.

[0044] Please refer to Figure 5 As shown, the present invention also provides a lighting system, including the above-mentioned optical components; it also includes a plurality of LED light sources 61 arranged in an array and a light diffuser 62 for converting the point light source of the LED light source 61 into a surface light source, and the light emitted by the light diffuser 62 passes through the first lens group 1.

[0045] When the lighting system is used to illuminate the three-dimensional structure 5 of the object to be tested, an LED light source plus a lighting lens group can be used to replace an ordinary LED light source or a collimated laser light source, thereby greatly reducing the detection cost. In addition, the second divergence angle β of the light reaching the surface of the three-dimensional structure 5 of the object to be tested is greatly reduced compared to the first divergence angle α emitted from the light source. When used for defect detection of three-dimensional contact lenses, the requirements for detecting tiny defects in contact lenses can be met, effectively improving the contact lens defect detection capability, and having strong practicality.

[0046] Please refer to Figure 6 and Figure 7 As shown, the present invention also provides an imaging system, including the above-mentioned lighting system; and also includes a transparent carrier 7 for placing the three-dimensional structure 5 of the object to be tested, and an image acquisition device 8 for acquiring images of the three-dimensional structure 5 of the object to be tested. Specifically, the image acquisition device 8 can use an industrial lens and camera assembly to acquire images of contact lenses, so as to facilitate defect analysis thereof.

[0047] Figure 7 The present invention is to detect the three-dimensional structure 5 of the object to be detected, specifically a schematic diagram of a defective lens for detecting a three-dimensional contact lens; wherein the defective lens includes three defects such as a transparent annular structure, a transparent broken lens, and a tear.

[0048] The imaging system also includes a first driving device 9 for driving the LED light source 61 and the light diffuser 62 to move as a whole, and a second driving device 10 for driving the LED light source 61, the light diffuser 62, the first lens group 1, the filter element 3, and the aperture stop 2 to move as a whole, so as to facilitate adaptive adjustment of the imaging system.

[0049] This imaging system is particularly suitable for LED light sources with low cost, stable performance and high cost-effectiveness. When detecting the three-dimensional structure 5 of the object to be tested, an LED light source plus an illumination lens group can be used to replace an ordinary LED light source or a collimated laser light source, thereby greatly reducing the detection cost. In addition, the second divergence angle β of the light reaching the surface of the three-dimensional structure 5 of the object to be tested is greatly reduced compared to the first divergence angle α emitted from the light source. When used for defect detection of three-dimensional contact lenses, it can meet the requirements for detecting tiny defects of contact lenses, effectively improve the defect detection capability of contact lenses, and has strong practicality.

[0050] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention is disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments according to the technology of the present invention are all within the scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.

Claims

1. An optical component, characterized in that: It comprises a first lens group (1), an aperture stop (2), a filter element (3) and a second lens group (4) arranged along the optical axis direction; A light source (6) emits light with a first divergence angle α, which is then angle-reflected after passing through a first lens group (1); when the angle-reflected light passes through an aperture stop (2) and a filter element (3), the aperture stop (2) and the filter element (3) modulate the angle and intensity of the light, thereby limiting and reducing the divergence angle of the light and modulating the intensity of light with different divergence angles to a desired intensity; The light after the angle and intensity modulation is deflected again after passing through the second lens group (4), so that when the light reaches the surface of the three-dimensional structure (5) of the object to be measured, the illumination angles at different spatial positions are different and the illumination intensity is the same, and the second divergence angle β of the illumination light at each position of the three-dimensional structure (5) of the object to be measured is smaller than the first divergence angle α; The three-dimensional structure (5) of the object to be tested is a three-dimensional contact lens; The equivalent focal length f2 of the second lens group (4) is a positive value, the image plane of the light source (6) formed by the first lens group (1) is located before the light entrance surface of the second lens group (4), and the distance between the image plane of the light source (6) formed by the first lens group (1) and the light entrance surface of the second lens group (4) is greater than or less than the equivalent focal length f2 of the second lens group (4), so as to ensure that the shape of the wavefront of the outgoing light beam is as close to the curved surface shape of the three-dimensional structure (5) of the object to be measured as possible, and the propagation direction of the light at each spatial position is consistent with the surface normal direction of the three-dimensional structure (5) of the object to be measured.

2. The optical component according to claim 1, wherein: The first lens group (1) comprises a first light-inlet lens (11) and a first light-outlet lens (12); the light-inlet surface and the light-outlet surface of the first light-inlet lens (11) are both convex structures; the light-inlet surface of the first light-outlet lens (12) is a concave structure, and the light-outlet surface of the first light-outlet lens (12) is a flat or convex structure; an air gap between the first light-inlet lens (11) and the first light-outlet lens (12) is 0 or a value greater than 0; Alternatively, the first lens group (1) comprises a single lens or a double cemented achromatic lens, the light entrance surface of the first lens group (1) is a convex structure, and the light exit surface of the first lens group (1) is a flat or convex structure.

3. The optical component according to claim 1, wherein: The second lens group (4) comprises a second light-incoming lens (41) and a second light-outgoing lens (42); the light-incoming surface of the second light-incoming lens (41) is a plane or convex structure, and the light-outgoing surface of the second light-incoming lens (41) is a concave structure; both the light-incoming surface and the light-outgoing surface of the second light-outgoing lens (42) are convex structures; an air gap between the second light-incoming lens (41) and the second light-outgoing lens (42) is 0 or a value greater than 0; Alternatively, the second lens group (4) comprises a single lens or a double cemented achromatic lens, the light entrance surface of the second lens group (4) is a plane or convex structure, and the light exit surface of the second lens group (4) is a convex structure.

4. The optical component according to claim 1, wherein: The equivalent focal length f1 of the first lens group (1) is a positive value; the light source (6) is located before the light entrance surface of the first lens group (1), and the distance l1 to the light entrance surface is greater than the equivalent focal length f1 of the first lens group (1); the distance l2 between the image plane of the light source (6) formed by the first lens group (1) and the light exit surface of the first lens group (1) satisfies 1 / l1+1 / l2=1 / f1; The distance l1 between the light source (6) and the light entrance surface of the first lens group (1) can be continuously adjusted under the premise that it is greater than the equivalent focal length f1 of the first lens group (1); The positions of the first lens group (1), the aperture stop (2) and the filter element (3) as a whole are adjusted as the distance l1 between the light source (6) and the light entrance surface of the first lens group (1) is adjusted.

5. The optical component according to claim 1, wherein: The aperture diaphragm (2) adopts a variable diaphragm, which is provided with an opening (21). The variable diaphragm is driven by an diaphragm driving device (22) for driving the opening size of the variable diaphragm.

6. The optical component according to claim 1, wherein: The filter element (3) comprises a filter assembly turntable (31), a plurality of filters (32) with different transmittances arranged on the filter assembly turntable (31), and a filter driving device (33) drivingly connected to the filter assembly turntable (31), wherein the filter driving device (33) is used to drive the filter assembly turntable (31) to rotate so that the filters (32) with required transmittances are located in the light path.

7. A lighting system, characterized in that: The optical component comprises the optical component according to any one of claims 1 to 6; further comprising a plurality of LED light sources (61) arranged in an array and a light diffusion plate (62) for converting the point light source of the LED light source (61) into a surface light source, wherein the light emitted by the light diffusion plate (62) passes through the first lens group (1).

8. An imaging system, characterized in that: It comprises the lighting system according to claim 7; and further comprises a transparent carrier (7) for placing the three-dimensional structure (5) of the object to be measured, and an image acquisition device (8) for acquiring an image of the three-dimensional structure (5) of the object to be measured.

9. The imaging system according to claim 8, characterized in that: The invention also includes a first driving device (9) for driving the LED light source (61) and the light diffusion plate (62) to move as a whole, and a second driving device (10) for driving the LED light source (61), the light diffusion plate (62), the first lens group (1), the filter element (3), and the aperture stop (2) to move as a whole.

Images