An optical projection lens for observing the concave surface of a sphere suspended in a liquid

Abstract

The present invention discloses an optical projection lens for observing the concave surface of a sphere suspended in a liquid, comprising a first lens, a second lens, a third lens, an aperture stop and a fourth lens arranged in sequence from the image side to the object side; the first lens, the second lens, the third lens and the fourth lens are all positive lenses; the first lens, the second lens and the third lens are single-piece lenses; and the fourth lens is a cemented lens. The optical projection lens for observing the concave surface of a sphere suspended in a liquid of the present invention can work in the entire visible band, the observable diameter range can be up to 14.5 mm at most, and the maximum observable concave depth is 5 mm; the surfaces of all components are only composed of standard spherical surfaces and planes, with a simple structure and low cost; the surface and edge of the concave surface suspended in the liquid can be detected simultaneously, thereby improving the detection efficiency, and the imaging quality is high, and it can be used for the detection of contact lenses and the like.

Description

Technical Field

[0001] The invention relates to an optical projection lens for observing the concave surface of a sphere suspended in liquid, belonging to the technical field of concave surface detection. Background Art

[0002] The imaging systems on the market observe flat surfaces. However, in industrial applications, there are many requirements for imaging curved surfaces, such as concave surfaces. For example, before the finished contact lenses are packaged, it is necessary to detect whether there are defects on their surfaces and boundaries. However, since contact lenses have a certain degree of concavity, the traditional inspection method requires projecting the contact lens image on a large screen, and the operator needs to constantly touch the contact lens to observe the projection at different depths, which makes the workload huge. Summary of the invention

[0003] The present invention provides an optical projection lens for observing the concave surface of a sphere suspended in a liquid. The optical projection lens can simultaneously project and image the surface and edge of a similar concave surface of a sphere with a diameter equal to or less than 14.5 mm and a concavity equal to or less than 5 mm suspended in a liquid, without requiring intervention of other methods such as tomography, thereby greatly improving the efficiency of detection.

[0004] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0005] An optical projection lens for observing the concave surface of a sphere suspended in a liquid comprises a first lens, a second lens, a third lens, an aperture stop and a fourth lens which are arranged in sequence from the image side to the object side; the first lens, the second lens, the third lens and the fourth lens are all positive lenses; the first lens, the second lens and the third lens are single lenses; and the fourth lens is a cemented lens.

[0006] The optical projection lens for observing the concave surface of a sphere suspended in a liquid utilizes secondary imaging to stretch the field curvature of the system. At the same time, the aperture stop is placed between two groups of positive lenses to eliminate dispersion in the entire visible band. Halogen lamps can be used for illumination to magnify objects such as contact lenses onto the projector.

[0007] In order to further ensure the imaging effect, preferably, the first lens is a biconvex H-LAKA lens, the center thickness of the first lens is 12±0.1mm, and from the image side to the object side, the two sides of the first lens are the first image side surface and the first object side surface, the curvature of the first image side surface is 46.6±0.01mm, and the curvature of the first object side surface is -325.3±0.01mm.

[0008] In order to further ensure the imaging effect, preferably, the second lens is a H-ZK10L meniscus single lens with positive refractive power, the center thickness of the second lens is 11.9±0.1mm, and from the image side to the object side, the two sides of the second lens are the second image side surface and the second image-object side surface, the curvature of the second image side surface is 16.1±0.01mm, and the curvature of the second object side surface is 178.2±0.01mm.

[0009] In order to further ensure the imaging effect, preferably, the third lens is a biconvex H-LAK53A lens with positive refractive power, the center thickness of the third lens is 12±0.1mm, and from the image side to the object side, the two sides of the third lens are the third image side surface and the third object side surface respectively, the curvature of the third image plane is 41.9±0.01mm, and the curvature of the third object side surface is -67.5±0.01mm.

[0010] In order to further ensure the imaging effect, preferably, from the image side to the object side, the fourth lens is composed of a H-ZK10L / H-ZF72A cemented lens with positive refractive power, the two sides of the H-ZK10L lens are the fourth A image side surface and the fourth A object side surface, and the two sides of the H-ZF72A lens are the fourth B image side surface and the fourth B object side surface; the fourth A image side surface is convex with a curvature of 31.3±0.01mm; the fourth A object side surface is convex with a curvature of 10±0.01mm; the fourth B image side surface is concave with a curvature of 10±0.01mm; the fourth B object side surface is convex with a curvature of 21.5±0.01mm; the center thickness of the H-ZK10L lens is 11.8±0.1mm, and the center thickness of the H-ZF72A lens is 8.5±0.1mm.

[0011] Further preferably, the center interval between the first lens and the second lens is 33.6±0.1 mm; the center interval between the second lens and the third lens is 27.6±0.1 mm; the center interval between the third lens and the aperture stop is 12.3±0.1 mm; and the center interval between the aperture stop and the fourth lens is 0 mm.

[0012] The optical projection lens for observing the concave surface of a sphere suspended in a liquid is used to work in the entire visible light band; the maximum diameter of the object that can be observed is 14.5 mm and the maximum depth is 5 mm.

[0013] The optical projection lens for observing the concave surface of a sphere suspended in a liquid is composed of two lens groups with positive focal lengths. The aperture is located between the two positive lens groups. The first lens group forms an image between the two lens groups, and then the second positive lens group forms an image on the focal plane, which stretches the depth of field of the lens. The lens uses three single lenses and one cemented lens to eliminate chromatic aberration in the entire visible light range, so that the invented lens can be used on a projector with a halogen lamp as a light source. Such a lens composed of two positive lens groups with intermediate imaging can stretch the field curvature to a greater extent, so that the surface and edge of the concave surface suspended in the liquid can be observed simultaneously.

[0014] The technologies not mentioned in the present invention are all referred to the prior art.

[0015] The optical projection lens for observing the concave surface of a sphere suspended in a liquid can work in the entire visible band, the observable diameter range can be up to 14.5 mm at most, and the maximum observable concave depth is 5 mm; the surfaces of all components are only composed of standard spherical surfaces and planes, the structure is simple, and the cost is low; the surface and edge of the concave surface suspended in the liquid can be detected simultaneously, the detection efficiency is improved, and the imaging quality is high, and the lens can be used for the detection of contact lenses and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The optical projection lens component marking and distance marking for observing the concave surface of a sphere suspended in a liquid according to the present invention;

[0017] Figure 2 The invention provides marking of each lens and surface marking of an optical projection lens for observing the concave surface of a sphere suspended in a liquid;

[0018] Figure 3 A schematic cross-sectional view of the optical projection lens for observing the concave surface of a sphere suspended in a liquid according to the present invention when observing the concave surface of a sphere suspended in a liquid;

[0019] Figure 4 A schematic diagram of the object to be measured and the cross section of light when the optical projection lens for observing the concave surface of a sphere suspended in liquid according to the present invention observes the concave surface of the sphere suspended in liquid;

[0020] Figure 5 The MTF curve of a contact lens with a diameter of 14.5 mm is detected by the optical projection lens for observing the concave surface of a sphere suspended in a liquid according to the present invention;

[0021] Figure 6 This is a picture of a contact lens with a diameter of 14.5 mm imaged by an optical projection lens for observing the concave surface of a sphere suspended in a liquid according to the present invention. DETAILED DESCRIPTION

[0022] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0023] like Figure 1-2 As shown, an optical projection lens for observing the concave surface of a sphere suspended in a liquid comprises a first lens 1, a second lens 2, a third lens 3, an aperture stop 4 and a fourth lens 5 which are arranged in sequence from the image side to the object side; the first lens 1, the second lens 2, the third lens 3 and the fourth lens 5 are all positive lenses; the first lens 1, the second lens 2 and the third lens 3 are single lenses; the fourth lens 5 is a cemented lens, and the design parameters of each lens element are shown in Table 1.

[0024] Table 1 is a table of design parameters of the above lens elements

[0025]

[0026] In the above table, from the image side to the object side, the two sides of the first lens 1 are the first image side surface 11 and the first object side surface 12; the two sides of the second lens 2 are the second image side surface 21 and the second object side surface 22; the two sides of the third lens 3 are the third image side surface 31 and the third object side surface 32; the fourth lens is composed of a positive refractive power H-ZK10L / H-ZF72A cemented lens, the two sides of the H-ZK10L lens are the fourth A image side surface 51 and the fourth A object side surface 52, and the two sides of the H-ZF72A lens are the fourth B image side surface 53 and the fourth B object side surface 54; in In the Surface Type column, all surfaces are standard, which means that only spherical or flat surfaces are included in this lens; a positive value of the radius of curvature means that the corresponding surface is bent in the direction of light propagation (design optical path), while a negative value indicates the corresponding surface is bent in the opposite direction of light propagation (design optical path); the Thickness column indicates the thickness of the component and the distance between adjacent components; the Material column indicates the material used for the corresponding component, and all of them are made of CDGM materials; the Clear Aperture column gives the clear diameter of each component, from which it can be seen that the diameter of all lenses is the same, which is 19mm.

[0027] Figure 1 to Figure 2 The above lens is composed of four lenses and an aperture diaphragm with adjustable size. The fourth lens 5 is the first element for the light of the object to be measured to enter the projection lens, and the input light enters the lens from the object to be measured through this element; the lens group of the fourth lens 5 and the third lens 3 forms an image of an object with a certain height and depth between the third lens 3 and the second lens 2 for the first time, and all the light passing through the fourth lens 5 passes through the aperture diaphragm 4, and the intermediate image is formed on the projector by the second lens 2 and the first lens 1, and the designed magnification is 15 times.

[0028] The above lens uses the secondary imaging method to stretch the field curvature of the system, and at the same time, the aperture stop is placed between the two groups of positive lenses to eliminate dispersion in the entire visible band. Halogen lamps can be used to illuminate and magnify objects such as contact lenses onto the projector. The cross-sectional schematic diagram of using the above lens to observe a concave surface suspended in a liquid is shown in the figure below. Figure 3 As shown, the schematic diagram of the object under test and the light profile is as follows Figure 4 As shown, MTF is Figure 5 As shown, the image of the 14.5mm diameter contact lens is as follows Figure 6 As shown, it can be seen that the above-mentioned lens has high image quality.

[0029] It is particularly pointed out that the protection scope of the present application is not limited to the above-mentioned detailed parameters disclosed. The lens is composed of three single lenses and a group of cemented lenses, as well as intermediate imaging and corresponding material selection, with the pupil close to the front surface of the fourth lens. Any modifications and changes based on this structure are within the scope of protection of the present invention.

Claims

1. An optical projection lens for observing the concave surface of a sphere suspended in a liquid, characterized in that: It is composed of a first lens, a second lens, a third lens, an aperture stop and a fourth lens which are arranged in sequence from the image side to the object side; the first lens, the second lens, the third lens and the fourth lens are all positive lenses; the first lens, the second lens and the third lens are single lenses; the fourth lens is a cemented lens; The first lens is a biconvex H-LAKA lens, the center thickness of the first lens is 12±0.1 mm, and the two sides of the first lens are the first image side surface and the first object side surface from the image side to the object side, the curvature of the first image side surface is 46.6±0.01 mm, and the curvature of the first object side surface is -325.3±0.01 mm; The second lens is a positive refractive power H-ZK10L meniscus single lens, the center thickness of the second lens is 11.9±0.1mm, and the two sides of the second lens are the second image side surface and the second object side surface from the image side to the object side, the curvature of the second image side surface is 16.1±0.01mm, and the curvature of the second object side surface is 178.2±0.01mm; The third lens is a biconvex H-LAK53A lens with positive refractive power. The center thickness of the third lens is 12±0.1 mm. From the image side to the object side, the two sides of the third lens are the third image side surface and the third object side surface. The curvature of the third image side surface is 41.9±0.01 mm, and the curvature of the third object side surface is -67.5±0.01 mm. From the image side to the object side, the fourth lens is composed of a positive refractive power H-ZK10L / H-ZF72A cemented lens, the two sides of the H-ZK10L lens are the fourth A image side surface and the fourth A object side surface, respectively, and the two sides of the H-ZF72A lens are the fourth B image side surface and the fourth B object side surface, respectively; the fourth A image side surface is convex, with a curvature of 31.3±0.01 mm; the fourth A object side surface is convex, with a curvature of 10±0.01 mm; the fourth B image side surface is concave, with a curvature of 10±0.01 mm; the fourth B object side surface is convex, with a curvature of 21.5±0.01 mm; the center thickness of the H-ZK10L lens is 11.8±0.1 mm, and the center thickness of the H-ZF72A lens is 8.5±0.1 mm; The center interval between the first lens and the second lens is 33.6±0.1 mm; the center interval between the second lens and the third lens is 27.6±0.1 mm; the center interval between the third lens and the aperture stop is 12.3±0.1 mm; and the center interval between the aperture stop and the fourth lens is 0 mm.

2. The optical projection lens for observing the concave surface of a sphere suspended in a liquid as claimed in claim 1, characterized in that: Designed to work in the entire visible light band; objects that can be observed have a maximum diameter of 14.5 mm and a maximum depth of 5 mm.

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