Telecentric projection lens structure

Abstract

The utility model relates to the field of lenses. The telecentric projection lens structure comprises a front lens group, a rear lens group and a diaphragm module, the front lens group is in threaded connection with the rear lens group, and the diaphragm module is in threaded connection with the front lens group; by arranging the front lens group, the rear lens group and the diaphragm module, the structure is modularized, the installation is convenient, a plurality of modules can be assembled at the same time, and the production efficiency is improved; by changing the lens into a telecentric lens, a projected image is unchanged in breadth size, negligible in distortion, consistent in stripe density and uniform in brightness in a field depth range, a measurement image with better quality can be obtained, the measurement precision is improved, and the lens is high in heat resistance, high in grinding precision and higher in projection permeability through an all-glass lens. A clearer projection image can be obtained, the resolution capability of a tiny structure is effectively improved, the connecting parts and the lens barrel are made of metal alloy materials, the thermal conductivity is good, the problems of virtual focus, out-of-focus and the like caused by deformation of the lens are avoided, and the focusing stability is high.

Description

Technical Field

[0001] The utility model relates to a projection lens, more specifically to a telecentric projection lens structure. Background Art

[0002] The projection lens is an optical element that projects the image on the image display element. The projection lenses on the market generally have multiple lenses, complex structures, and large sizes, which are not suitable for micro-projectors used by structured light sensors.

[0003] For general projection lenses, the projected image is smaller near and larger far. The image projected at an oblique angle appears trapezoidal on the plane, and the shape and brightness of the image change linearly from left to right. The short side of the trapezoid is close to the projection lens and has higher brightness, while the long side is far away from the projection lens and has lower brightness. The uneven brightness of the projected image is prone to overexposure on one side and underexposure on the other side when inspecting parts with high or low reflectivity, affecting the final measurement effect. Utility Model Content

[0004] The main technical problem solved by the utility model is to provide a telecentric projection lens structure, which can solve the above-mentioned problems.

[0005] To solve the above technical problems, according to one aspect of the utility model, more specifically a telecentric projection lens structure includes a front lens group, a rear lens group, and an aperture module. The front lens group and the rear lens group are threadedly connected, and the aperture module is threadedly connected to the front lens group.

[0006] Furthermore, the front lens group includes a first lens, a second lens, a third lens, a first pressure ring, a first spacer ring, a second pressure ring, and a front lens barrel. The third lens is located on the right side inside the front lens barrel. The second pressure ring is threadedly connected to the front lens barrel, and the right side of the second pressure ring contacts the left side of the third lens. The second lens, the first spacer ring, and the first lens are sequentially located inside the front lens barrel from right to left. The first pressure ring is threadedly connected to the front lens barrel, and the right side of the first pressure ring contacts the left side of the first lens.

[0007] Furthermore, the rear lens group includes a rear lens barrel, a fourth lens, a fifth lens, a sixth lens, a third pressure ring, a second spacer ring and a fourth pressure ring, the fourth lens is located on the left side inside the rear lens barrel, the third pressure ring is threadedly connected to the rear lens barrel, and the left side of the third pressure ring is in contact with the right side of the fourth lens, the fifth lens, the second spacer ring and the sixth lens are sequentially located inside the rear lens barrel from left to right, the fourth pressure ring is threadedly connected to the rear lens barrel, and the left side of the fourth pressure ring is in contact with the right side of the sixth lens, and the front lens barrel and the rear lens barrel are threadedly connected.

[0008] Furthermore, the aperture module includes an aperture, a cemented lens, and a fifth pressure ring. The cemented lens is provided inside the aperture. The fifth pressure ring is threadedly connected to the aperture, and the left side of the fifth pressure ring is in contact with the right side of the aperture.

[0009] Furthermore, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the cemented lens are all made of glass.

[0010] Furthermore, the second pressure ring, the first spacer ring, the front lens barrel, the first pressure ring, the rear lens barrel, the third pressure ring, the second spacer ring, the fourth pressure ring, the aperture, and the fifth pressure ring are all made of metal alloy.

[0011] Furthermore, the first lens and the fifth lens are biconvex lenses, and the second lens, the third lens, the fourth lens, and the sixth lens are meniscus lenses.

[0012] The beneficial effects of the telecentric projection lens structure of the utility model are:

[0013] By setting the front lens group, the rear lens group and the aperture module, the structure is modularized, which is easy to install. Multiple modules can be assembled at the same time to improve production efficiency. By changing it into a telecentric lens, the projected image can be kept in the same size within the depth of field, the distortion can be ignored, the fringe density is consistent, and the brightness is uniform, which is conducive to obtaining better quality measurement images and improving measurement accuracy. Through the all-glass lens, it has strong heat resistance, high grinding accuracy, and stronger projection transparency, so that clearer projection images can be obtained, and the resolution of tiny structures is effectively improved. The connecting parts and the lens barrel are made of metal alloy with good thermal conductivity and strong deformation resistance. The lens will not have problems such as out-of-focus and out-of-focus due to deformation, and the focusing stability is strong.

[0014] By arranging a plurality of lenses and a pressure ring, a small number of lenses, a simple structure, a small size and a high degree of integration are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The utility model is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0016] Figure 1 It is a schematic diagram of the overall structure of a telecentric projection lens structure of the utility model;

[0017] Figure 2 The utility model is a schematic diagram of the cross-sectional internal structure of a telecentric projection lens structure.

[0018] In the figure: 1, front lens group; 2, rear lens group; 3, aperture module; 11, first lens; 12, second lens; 13, third lens; 14, cemented lens; 15, fourth lens; 16, fifth lens; 17, sixth lens; 21, first pressure ring; 22, first spacer ring; 23, second pressure ring; 24, aperture; 25, fifth pressure ring; 26, third pressure ring; 27, second spacer ring; 28, fourth pressure ring; 31, front lens barrel; 32, rear lens barrel. DETAILED DESCRIPTION

[0019] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0020] According to one aspect of the present invention, Figure 1 As shown in FIG. 2 , a telecentric projection lens structure is provided, including a front lens group 1, a rear lens group 2, and an aperture module 3. The front lens group 1 and the rear lens group 2 are threadedly connected, and the aperture module 3 is threadedly connected to the front lens group 1, making the structure modular and making installation more convenient.

[0021] In this embodiment, the front lens group 1 includes a first lens 11, a second lens 12, a third lens 13, a first pressure ring 21, a first spacer ring 22, a second pressure ring 23, and a front lens barrel 31. The third lens 13 is located on the right side inside the front lens barrel 31. The second pressure ring 23 is threadedly connected to the front lens barrel 31, and the right side of the second pressure ring 23 contacts the left side of the third lens 13. The second lens 12, the first spacer ring 22, and the first lens 11 are located inside the front lens barrel 31 from right to left. The first pressure ring 21 is threadedly connected to the front lens barrel 31, and the right side of the first pressure ring 21 contacts the left side of the first lens 11. The front lens group 1 plays a magnifying role, magnifying the focused image by a certain magnification and projecting it.

[0022] In this embodiment, the rear lens group 2 includes a rear lens barrel 32, a fourth lens 15, a fifth lens 16, a sixth lens 17, a third pressure ring 26, a second spacer ring 27 and a fourth pressure ring 28. The fourth lens 15 is located on the left side inside the rear lens barrel 32. The third pressure ring 26 is threadedly connected to the rear lens barrel 32, and the left side of the third pressure ring 26 contacts the right side of the fourth lens 15. The fifth lens 16, the second spacer ring 27 and the sixth lens 17 are located from left to right inside the rear lens barrel 32. The fourth pressure ring 28 is threadedly connected to the rear lens barrel 32, and the left side of the fourth pressure ring 28 contacts the right side of the sixth lens 17. The front lens barrel 31 and the rear lens barrel 32 are threadedly connected. The rear lens group 2 is used for viewing.

[0023] In this embodiment, the aperture module 3 includes an aperture 24, a cemented lens 14, and a fifth pressure ring 25. The interior of the aperture 24 is provided with a cemented lens 14. The fifth pressure ring 25 is threadedly connected to the aperture 24, and the left side of the fifth pressure ring 25 is in contact with the right side of the aperture 24. The aperture 24 is a stepped short-axis lens seat. The first section has a smaller outer cylindrical surface with high precision and is used for radial positioning to ensure the coaxiality of the installation and prevent eccentricity. The second section is an external thread for installation and fixation, and is connected to the front lens barrel 31. The step end face from the threaded section to the third section of the outer cylindrical surface is used for axial positioning of the aperture 24 to ensure the axial position accuracy of the aperture hole and the cemented lens 14.

[0024] In this embodiment, the first lens 11, the second lens 12, the third lens 13, the fourth lens 15, the fifth lens 16, the sixth lens 17, and the cemented lens 14 are all made of glass; glass has good heat resistance, good processability, and high precision.

[0025] In this embodiment, the second pressure ring 23, the first spacer ring 22, the front lens barrel 31, the first pressure ring 21, the rear lens barrel 32, the third pressure ring 26, the second spacer ring 27, the fourth pressure ring 28, the aperture 24, and the fifth pressure ring 25 are all made of metal alloy; the metal alloy material has good processability, good thermal conductivity, and strong deformation resistance.

[0026] In this embodiment, the first lens 11 and the fifth lens 16 are biconvex lenses, and the second lens 12, the third lens 13, the fourth lens 15, and the sixth lens 17 are meniscus lenses.

[0027] The working principle of the device is: assemble the internal structures of the front lens group 1, the rear lens group 2 and the aperture module 3 in sequence, put the third lens 13 into the interior of the front lens barrel 31, and then press it with the second pressing ring 23, then put the second lens 12, the first spacer ring 22 and the first lens 11 into the interior of the front lens barrel 31 from right to left in sequence, and then press it with the first pressing ring 21, the rear lens group 3 puts the fourth lens 15 into the leftmost part of the interior of the rear lens barrel 32, and presses it with the third pressing ring 26, then puts the fifth lens 16, the second spacer ring 27 and the sixth lens 17 in sequence, and then presses it with the fourth pressing ring 28, the aperture module 3 puts the cemented lens 14 into the aperture 24, and then presses it with the fifth pressing ring 25, then the aperture module 3 is threadedly connected to the front lens barrel 31, and then the rear lens barrel 32 is threadedly connected to the front lens barrel 31.

[0028] The electrical components that appear in this article are all electrical components that exist in reality.

[0029] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention also fall within the protection scope of the present invention.

Claims

1. A telecentric projection lens structure, comprising a front lens group (1), a rear lens group (2), and an aperture module (3), characterized in that: The front lens group (1) and the rear lens group (2) are threadedly connected, and the aperture module (3) is threadedly connected to the front lens group (1).

2. The telecentric projection lens structure according to claim 1, characterized in that: The front lens group (1) comprises a first lens (11), a second lens (12), a third lens (13), a first pressure ring (21), a first spacer ring (22), a second pressure ring (23), and a front lens barrel (31); the third lens (13) is located on the right side inside the front lens barrel (31); the second pressure ring (23) is threadedly connected to the front lens barrel (31), and the right side of the second pressure ring (23) contacts the left side of the third lens (13); the second lens (12), the first spacer ring (22), and the first lens (11) are located inside the front lens barrel (31) in sequence from right to left; the first pressure ring (21) is threadedly connected to the front lens barrel (31), and the right side of the first pressure ring (21) contacts the left side of the first lens (11).

3. The telecentric projection lens structure according to claim 2, characterized in that: The rear lens group (2) comprises a rear lens barrel (32), a fourth lens (15), a fifth lens (16), a sixth lens (17), a third pressure ring (26), a second spacer ring (27) and a fourth pressure ring (28); the fourth lens (15) is located on the left side inside the rear lens barrel (32); the third pressure ring (26) is threadedly connected to the rear lens barrel (32), and the left side of the third pressure ring (26) contacts the right side of the fourth lens (15); the fifth lens (16), the second spacer ring (27) and the sixth lens (17) are located in sequence from left to right inside the rear lens barrel (32); the fourth pressure ring (28) is threadedly connected to the rear lens barrel (32), and the left side of the fourth pressure ring (28) contacts the right side of the sixth lens (17); and the front lens barrel (31) and the rear lens barrel (32) are threadedly connected.

4. The telecentric projection lens structure according to claim 3, characterized in that: The aperture module (3) comprises an aperture (24), a cemented lens (14), and a fifth pressure ring (25); the cemented lens (14) is arranged inside the aperture (24); the fifth pressure ring (25) is threadedly connected to the aperture (24); and the left side of the fifth pressure ring (25) is in contact with the right side of the aperture (24).

5. The telecentric projection lens structure according to claim 4, characterized in that: The first lens (11), the second lens (12), the third lens (13), the fourth lens (15), the fifth lens (16), the sixth lens (17), and the cemented lens (14) are all made of glass.

6. The telecentric projection lens structure according to claim 5, characterized in that: The second pressure ring (23), the first spacer ring (22), the front lens barrel (31), the first pressure ring (21), the rear lens barrel (32), the third pressure ring (26), the second spacer ring (27), the fourth pressure ring (28), the diaphragm (24), and the fifth pressure ring (25) are all made of metal alloy.

7. The telecentric projection lens structure according to claim 3, characterized in that: The first lens (11) and the fifth lens (16) are biconvex lenses, and the second lens (12), the third lens (13), the fourth lens (15) and the sixth lens (17) are crescent lenses.

Images