Optical engine and electronic equipment

Abstract

The invention relates to the technical field of optics, in particular to an optical engine and electronic equipment. According to the optical engine provided by the invention, the light emitting direction of the light source module is the same as the light emitting direction of the projection lens, so that the light emitting direction of the light source module is the same as the light emitting direction of the projection lens, or an included angle is formed between the light emitting direction of the light source module and the light emitting direction of the projection lens; due to the arrangement of the dodging module, a gap is formed between the light source module and the projection lens, the heat transfer distance is enlarged, the influence of heat of the light source module on the temperature of components of the projection lens is reduced, and the temperature drift of the optical engine is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of optical technology, and in particular to an optical engine and electronic equipment. Background Art

[0002] In the field of machine vision, a specified optical pattern is projected onto a target object through an optical engine, and a camera is used to capture the distorted pattern of the corresponding optical pattern after it passes through the target object. By analyzing the deformation of the pattern, the three-dimensional shape and surface texture of the object can be determined.

[0003] Optical engines are crucial components in the field of machine vision, enabling stable and accurate generation of structured light signals. However, in related technologies, optical engines are compact and their components are susceptible to heat from the light source module, which can affect projection clarity and detection accuracy. Summary of the Invention

[0004] The present disclosure provides an optical engine and an electronic device, so that the optical engine has low-temperature drift performance.

[0005] In order to achieve the above objectives, the present disclosure adopts the following technical solutions:

[0006] A first aspect of the present disclosure provides an optical engine, comprising: a projection lens and an illumination module, wherein the projection lens is fixedly connected to the illumination module; the illumination module comprises a light source module, a homogenization module, and a spatial light modulator;

[0007] The light emitted by the light source module passes through the light homogenization module and is emitted to the spatial light modulator; the spatial light modulator generates a structured light pattern and projects it to the target object through the projection lens;

[0008] The light source module emits light along a first direction, and the projection lens emits light along a second direction; the second direction is not opposite to the first direction.

[0009] Compared with the prior art, the optical engine provided by the first aspect of the present disclosure has the following advantages:

[0010] The optical engine provided by the present disclosure limits the direction of light emitted by the light source module and the direction of light emitted by the projection lens to be not opposite, so that the direction of light emitted by the light source module and the direction of light emitted by the projection lens are the same or have a certain angle. Since the light averaging module directs the light emitted by the light source module toward the projection lens, a gap is created between the light source module and the projection lens, thereby increasing the physical distance between the light source module and the projection lens, extending the heat transfer distance, thereby reducing the impact of the heat of the light source module on the temperature of the projection lens components, and reducing the temperature drift of the optical engine.

[0011] As an improvement to the above optical engine of the present disclosure, the central axis of the projection lens extends along the second direction; the central axis of the light source module extends along the first direction;

[0012] The central axis of the projection lens and the central axis of the light source module are skew lines.

[0013] As an improvement to the above-mentioned optical engine disclosed in the present invention, the central axis of the projection lens and the central axis of the light source module are coplanar straight lines, and the plane determined by the central axis of the projection lens and the central axis of the light source module is a first plane; the projection lens and the light source module are spaced apart in the first plane.

[0014] As an improvement of the above optical engine disclosed herein, the projection lens is located on a side of the light source module from which light is emitted; and along an extension direction of a central axis of the light source module, a gap is provided between the projection lens and the light source module.

[0015] As an improvement to the above optical engine disclosed herein, an extension direction of a central axis of the projection lens is parallel to an extension direction of a central axis of the light source module, so that an angle between the second direction and the first direction is equal to 0°.

[0016] As an improvement of the above optical engine disclosed in the present invention, the light homogenization module and the spatial light modulator are located in the interval between the projection lens and the light source module.

[0017] As an improvement of the above-mentioned optical engine disclosed in the present invention, the light homogenization module includes a prism, a shell portion and a fixing member, the prism is located in the shell portion, and the fixing member is fixedly connected to the shell portion and elastically contacts the prism.

[0018] As an improvement to the above optical engine disclosed herein, the fixing member is a spring screw.

[0019] As an improvement to the above-mentioned optical engine disclosed in the present invention, the image source plane of the spatial light modulator, the main plane of the projection lens, and the extended projection plane of the target object intersect on the same straight line, satisfying Scham's law; the angle β between the image source plane and the optical axis is 80° to 90°.

[0020] As an improvement of the above optical engine of the present disclosure, the light source module includes a light source and a first lens, a second lens, and a third lens arranged in sequence along the light emission direction of the optical axis;

[0021] The light homogenization module includes a light homogenization element, a fourth lens, a reflector, a fifth lens, and a prism, which are sequentially arranged along the optical emission direction of the optical axis.

[0022] As an improvement of the above-mentioned optical engine disclosed in the present invention, the first lens is a meniscus lens, the second lens is a meniscus lens, the third lens is a meniscus lens, the fourth lens is a biconvex lens, and the fifth lens is a biconvex lens.

[0023] As an improvement to the above-mentioned optical engine disclosed in the present invention, the radius of curvature R011 of the incident surface of the first lens is -25mm to -15mm, and the radius of curvature R012 of the exit surface is -10mm to -1mm; the radius of curvature R021 of the incident surface of the second lens is -80mm to -70mm, and the radius of curvature R022 of the exit surface is -15mm to -5mm; the radius of curvature R031 of the incident surface of the third lens is -10mm to -1mm, and the radius of curvature R032 of the exit surface is -10mm to -1mm; the radius of curvature R051 of the incident surface of the fourth lens is 100mm to 110mm, and the radius of curvature R052 of the exit surface is 100mm to 110mm; the radius of curvature R071 of the incident surface of the fifth lens is -40mm to -30mm, and the radius of curvature R072 of the exit surface is 30mm to 40mm.

[0024] As an improvement to the above-mentioned optical engine disclosed herein, the focal length f01 of the first lens is 5mm to 15mm; the focal length f02 of the second lens is 10mm to 20mm; the focal length f03 of the third lens is -80mm to -70mm; the focal length f05 of the fourth lens is 60mm to 70mm; and the focal length f07 of the fifth lens is -25mm to -15mm.

[0025] As an improvement to the above-mentioned optical engine disclosed in the present invention, the focal length f01 of the first lens and the effective focal length f of the projection lens satisfy 0<|f01 / f|<1; the focal length f02 of the second lens and the effective focal length f of the projection lens satisfy 0.5<|f02 / f|<1.5; the focal length f03 of the third lens and the effective focal length f of the projection lens satisfy 2<|f03 / f|<4; the focal length f05 of the fourth lens and the effective focal length f of the projection lens satisfy 2<|f05 / f|<4; the focal length f07 of the fifth lens and the effective focal length f of the projection lens satisfy 0.5<|f07 / f|<1.5.

[0026] As an improvement to the above-mentioned optical engine disclosed herein, the refractive index N01 of the first lens is 1.7-1.9, and the Abbe number V01 is 20-25; the refractive index N02 of the second lens is 1.7-1.9, and the Abbe number V02 is 45-50; the refractive index N03 of the third lens is 1.7-1.9, and the Abbe number V03 is 45-50; the refractive index N05 of the fourth lens is 1.7-1.9, and the Abbe number V04 is 45-50; the refractive index N07 of the fifth lens is 1.7-1.9, and the Abbe number V05 is 45-50.

[0027] As an improvement of the above optical engine of the present disclosure, the center thickness GT01 of the first lens is 3mm to 6mm; the center thickness GT02 of the second lens is 2mm to 6mm;

[0028] The center thickness GT03 of the third lens is 1 mm to 4 mm; the center thickness GT05 of the fourth lens is 1 mm to 4 mm; and the center thickness GT07 of the fifth lens is 3 mm to 6 mm.

[0029] As an improvement to the above-mentioned optical engine disclosed in the present invention, the air spacing distance AT00 between the light source and the first lens along the optical axis is 0 mm to 2 mm; the air spacing distance AT01 between the first lens and the second lens along the optical axis is 0 mm to 2 mm; the air spacing distance AT02 between the second lens and the third lens along the optical axis is 0 mm to 2 mm; the air spacing distance AT03 between the third lens and the light homogenizing element along the optical axis is 1 mm to 4 mm; the air spacing distance AT04 between the light homogenizing element and the fourth lens along the optical axis is 1 mm to 3 mm; the air spacing distance AT05 between the fourth lens and the center of the reflector along the optical axis is 8 mm to 11 mm; the air spacing distance AT06 between the center of the reflector and the fifth lens along the optical axis is 9 mm to 12 mm; the air spacing distance AT07 between the fifth lens and the prism along the optical axis is 3 mm to 7 mm; and the air spacing distance AT08 between the prism and the image source plane of the spatial light modulator along the optical axis is 0 mm to 2 mm.

[0030] As an improvement to the above-mentioned optical engine of the present disclosure, the projection lens comprises: a first lens group, a second lens group, a third lens group, and a fourth lens group, arranged in sequence along the optical axis from one side of the projection surface to one side of the image source surface of the spatial light modulator, with an aperture stop disposed between the second lens group and the third lens group; wherein the projection surface is used to receive a projection image;

[0031] The optical power of the first lens group is negative, the optical power of the second lens group is positive, the optical power of the third lens group is negative, and the optical power of the fourth lens group is positive;

[0032] The image source plane is arranged perpendicularly or obliquely relative to the optical axis, and an angle θ between a normal direction of the image source plane and the optical axis is 0° to 10°.

[0033] As an improvement to the above-mentioned optical engine of the present invention, the focal length fa of the first lens group satisfies |fa / f|=1.4~1.9 with the effective focal length f of the projection lens, the focal length fb of the second lens group satisfies fb / f=1.2~2.4 with the effective focal length f of the projection lens, the focal length fc of the third lens group satisfies |fc / f|=3.2~8.7 with the effective focal length f of the projection lens, and the focal length fd of the fourth lens group satisfies fd / f=0.7~1.3 with the effective focal length f of the projection lens.

[0034] As an improvement to the above-mentioned optical engine disclosed in the present invention, the focal length fa of the first lens group is -26.5mm to -12.4mm, the focal length fb of the second lens group is 16.5mm to 25.3mm, the focal length fc of the third lens group is -95mm to -45mm, and the focal length fd of the fourth lens group is 10mm to 14mm.

[0035] As an improvement to the above-mentioned optical engine disclosed in the present invention, the axial spacing d12 between the first lens group and the second lens group is 0.2 mm to 7.3 mm, the axial spacing d23 between the second lens group and the third lens group is 2.9 mm to 11.9 mm, and the axial spacing d34 between the third lens group and the fourth lens group is 1.8 mm to 2.9 mm.

[0036] As an improvement to the above-mentioned optical engine of the present disclosure, the projection lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens along the optical axis from the projection surface to the image source surface, wherein the first lens, the second lens, and the third lens form a first lens group; the fourth lens forms the second lens group, the fifth lens forms the third lens group, and the sixth lens, the seventh lens, and the eighth lens form the fourth lens group.

[0037] As an improvement to the above-mentioned optical engine of the present invention, the first lens is a convex-plano lens with positive optical power, the second lens is a convex-concave lens with negative optical power, the third lens is a concave-convex lens with negative optical power, the fourth lens is a concave-convex lens with positive optical power, the fifth lens is a convex-concave lens with negative optical power, the sixth lens is a biconcave lens with negative optical power, the seventh lens is a biconvex lens with positive optical power, the sixth lens and the seventh lens are cemented lenses, and the eighth lens is a biconvex lens with positive optical power.

[0038] As an improvement to the above-mentioned optical engine of the present disclosure, the projection lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens along the optical axis from the projection surface to the image source surface, wherein the first lens forms the first lens group; the second lens, the third lens, and the fourth lens form the second lens group, the fifth lens forms the third lens group, and the sixth lens, the seventh lens, the eighth lens, and the ninth lens form the fourth lens group.

[0039] As an improvement to the above-mentioned optical engine of the present invention, the first lens is a convex-plano lens or a convex-concave lens with positive optical power, the second lens is a convex-concave lens with negative optical power, the third lens is a concave-convex lens or a plano-concave lens or a biconcave lens with negative optical power, the fourth lens is a concave-convex lens or a biconvex lens with positive optical power, the fifth lens is a convex-concave lens with negative optical power, the sixth lens is a biconcave lens with negative optical power, the seventh lens is a biconvex lens with positive optical power, the eighth lens is a biconvex lens with positive optical power, and the ninth lens is a convex-plano lens or a convex-concave lens with positive optical power.

[0040] As an improvement to the above-mentioned optical engine of the present disclosure, the curvature radius R11 of the projection side surface of the first lens is 18.6 mm to 32.1 mm, and the curvature radius R12 of the image source side surface is greater than or equal to 110.8 mm; the curvature radius R21 of the projection side surface of the second lens is 10.1 mm to 18.8 mm, and the curvature radius R22 of the image source side surface is 4.2 mm to 10.2 mm; the curvature radius R31 of the projection side surface of the third lens is -68 mm to -6.8 mm, and the curvature radius R32 of the image source side surface is -16.2 mm to 13.7 mm; the curvature radius R41 of the projection side surface of the fourth lens is -34 mm to 55.5 mm, and the curvature radius R42 of the image source side surface is -39.6 mm to 6.8 mm. -10.3mm; the curvature radius R51 of the projection-side surface of the fifth lens is 16.36mm-43mm, and the curvature radius R52 of the image-source-side surface is 10.4mm-26.2mm; the curvature radius R61 of the projection-side surface of the sixth lens is -76.2mm--18.2mm, and the curvature radius R62 of the image-source-side surface is 30.7mm-39mm; the curvature radius R71 of the projection-side surface of the seventh lens is 30.7mm-39mm, and the curvature radius R72 of the image-source-side surface is -29.4mm--9.8mm; the curvature radius R81 of the projection-side surface of the eighth lens is 19.82mm-48.7mm, and the curvature radius R82 of the image-source-side surface is -50.3mm--25.74mm;

[0041] Wherein, the projection side surface faces the projection surface, and the image source side surface faces the image source surface.

[0042] As an improvement to the above-mentioned optical engine disclosed in the present invention, the center thickness GT1 of the first lens is 3 mm to 5.1 mm; the center thickness GT2 of the second lens is 3 mm to 4 mm; the center thickness GT3 of the third lens is 1.5 mm to 3 mm; the center thickness GT4 of the fourth lens is 1.6 mm to 2.5 mm; the center thickness GT5 of the fifth lens is 3 mm to 5.2 mm; the center thickness GT6 of the sixth lens is 1.5 mm to 2.3 mm; the center thickness GT7 of the seventh lens is 3 mm to 5.1 mm; and the center thickness GT8 of the eighth lens is 3 mm to 4.8 mm.

[0043] As an improvement to the above-mentioned optical engine disclosed in the present invention, the air spacing distance AT1 between the first lens and the second lens along the optical axis is 0.2mm-2.2mm; the air spacing distance AT2 between the second lens and the third lens along the optical axis is 2.2mm-4.5mm; the air spacing distance AT3 between the third lens and the fourth lens along the optical axis is 0.2mm-7.3mm; the air spacing distance AT4 between the fourth lens and the aperture stop along the optical axis is 0.6mm-8.5mm; the air spacing distance AT5 between the aperture stop and the fifth lens along the optical axis is 1.2mm-3.4mm; the air spacing distance AT6 between the fifth lens and the sixth lens along the optical axis is 1.8mm-2.9mm; the sixth lens and the seventh lens are cemented lenses; and the air spacing distance AT7 between the seventh lens and the eighth lens along the optical axis is 0.2mm-1.38mm.

[0044] As an improvement to the above-mentioned optical engine disclosed in the present invention, the focal length f1 of the first lens is 25mm to 48mm; the focal length f2 of the second lens is -33mm to -13mm; the focal length f3 of the third lens is -19mm to -13mm; the focal length f4 of the fourth lens is 17mm to 25mm; the focal length f5 of the fifth lens is -95mm to -46mm; the focal length f6 of the sixth lens is -23mm to -15mm; the focal length f7 of the seventh lens is 13mm to 20.6mm; and the focal length f8 of the eighth lens is 15mm to 27.6mm.

[0045] As an improvement to the above-mentioned optical engine of the present disclosure, the refractive index N1 of the first lens is 1.73-1.88, and the Abbe number V1 is 39.2-54.7; the refractive index N2 of the second lens is 1.52-1.9, and the Abbe number V2 is 31.3-58.6; the refractive index N3 of the third lens is 1.7-1.85, and the Abbe number V3 is 30-52.3; the refractive index N4 of the fourth lens is 1.83-1.85, and the Abbe number V4 is 23. 8 to 42.7; the refractive index N5 of the fifth lens is 1.73 to 1.78, and the Abbe number V5 is 25.7 to 28.3; the refractive index N6 of the sixth lens is 1.76 to 1.95, and the Abbe number V6 is 17.9 to 26.6; the refractive index N7 of the seventh lens is 1.62 to 1.83, and the Abbe number V7 is 42.7 to 63.4; the refractive index N8 of the eighth lens is 1.75 to 1.88, and the Abbe number V8 is 39.2 to 52.3.

[0046] As an improvement of the above optical engine of the present disclosure, the curvature radius R91 of the projection side surface of the ninth lens is 19.7 mm to 24.4 mm, and the curvature radius R92 of the image source side surface is greater than or equal to 221.5 mm;

[0047] The center thickness GT9 of the ninth lens is 4 mm to 5.2 mm;

[0048] The air spacing distance AT8 between the eighth lens and the ninth lens along the optical axis is 0.2 mm;

[0049] The focal length f9 of the ninth lens is 34 mm to 43.1 mm;

[0050] The refractive index N8 of the ninth lens is 1.57-1.62, and the Abbe number V8 is 60.3-71.3.

[0051] As an improvement to the above-mentioned optical engine disclosed herein, the effective focal length f of the projection lens is 8 mm to 14 mm, the aperture number Fno is F / 1.7 to F / 4.2, the size IMG of the image source surface of the spatial light modulator is 8 mm to 12 mm, the operating band is 390 nm to 700 nm, the total optical length TTL of the projection lens is 50 mm to 85 mm, and the system back focus BFL is 17.5 mm to 21.4 mm.

[0052] As an improvement to the above optical engine of the present disclosure, the distortion curve of the projection lens changes monotonically over the entire field of view;

[0053] The MTF contrast ratio of each field of view of the projection lens at a spatial frequency of 93 cycles / mm is greater than 0.7;

[0054] The relative illumination of the entire viewing field of the projection lens is greater than 96%.

[0055] As an improvement to the above optical engine disclosed herein, all lenses are made of glass and all lenses are spherical lenses.

[0056] A second aspect of the present disclosure provides an electronic device comprising: a camera and the optical engine described in any one of the first aspects, wherein the optical engine is used to project a pattern toward the surface of the object to be measured, and the camera is used to capture light reflected from the surface of the object to be measured and form an image.

[0057] The electronic device provided in the second aspect of the present disclosure includes the optical engine described in the first aspect, so the electronic device provided in the second aspect of the present disclosure also has the same advantages as the optical engine described in the first aspect.

[0058] In addition to the technical problems solved by the present disclosure, the technical features that constitute the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions described above, other technical problems that can be solved by the optical engine and electronic device provided by the present disclosure, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments of the present disclosure or the description of the prior art. Obviously, the drawings described below are only part of the embodiments of the present disclosure. These drawings and text descriptions are not intended to limit the scope of the concept of the present disclosure in any way, but to illustrate the concept of the present disclosure for those skilled in the art by referring to specific embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0060] Figure 1 Schematic diagram of the structure of an optical engine in the prior art;

[0061] Figure 2 A schematic diagram of the structure of an optical engine provided in an embodiment of the present disclosure;

[0062] Figure 3 A schematic cross-sectional view of an optical engine provided by an embodiment of the present disclosure;

[0063] Figure 4 A schematic diagram of the structure of an optical engine provided in some embodiments of the present disclosure;

[0064] Figure 5 A schematic diagram of the structure of an optical engine provided in some other embodiments of the present disclosure;

[0065] Figure 6 This is the principle diagram of Sham's law;

[0066] Figure 7 A schematic diagram of the structure of an optical engine provided by an embodiment of the present disclosure;

[0067] Figure 8 A schematic diagram of the structure of an optical engine provided in an embodiment of the present disclosure;

[0068] Figure 9 A schematic diagram of a portion of the structure of an optical engine provided in an embodiment of the present disclosure;

[0069] Figure 10 It is a thermal analysis image of an optical engine in the prior art;

[0070] Figure 11Thermal analysis images of the optical engine provided by the embodiments of the present disclosure;

[0071] Figure 12 A schematic diagram of the structure of a projection lens provided in some embodiments of the present disclosure;

[0072] Figure 13 A distortion diagram of the projection lens provided in an embodiment of the present disclosure;

[0073] Figure 14 An MTF curve diagram of the projection lens provided in an embodiment of the present disclosure;

[0074] Figure 15 A relative illumination curve diagram of a projection lens provided in an embodiment of the present disclosure;

[0075] Figure 16 A schematic diagram of the structure of a projection lens provided in some embodiments of the present disclosure;

[0076] Figure 17 This is a schematic structural diagram of a projection lens provided in some other embodiments of the present disclosure. DETAILED DESCRIPTION

[0077] With the continuous advancement of technology, machine vision has been widely used in industrial automation, quality control, medical imaging, security monitoring, and robotics. Structured light plays a key role in this field. An optical engine projects a specified optical pattern onto a target object. A camera captures the distortion of the corresponding optical pattern after it passes through the target object. By analyzing the deformation of the pattern, the object's three-dimensional shape and surface texture can be determined.

[0078] Optical engines, which enable stable and accurate generation of structured light signals, are crucial components in the field of machine vision. As the demand for imaging precision continues to increase, the thermal expansion and contraction of components within optical engines due to temperature fluctuations is becoming increasingly significant. The temperature-dependent behavior of components is known as temperature drift.

[0079] In existing optical engines, when implementing oblique projection or non-orthographic projection scenarios, problems such as image blur, difficulty in focusing, and insufficient depth of field are often encountered, which cannot meet the needs of high-precision imaging.

[0080] To this end, the presently disclosed embodiments incorporate an optical engine structure based on Scheimpflug's law, known as the Scheimpflug Optical Engine. The principal plane of the projection lens, the image source plane, and the projected object plane are extended and intersect on the same straight line, effectively expanding the system's depth of field and enabling uniform, clear images across the entire projection area at varying tilt angles.

[0081] The disclosed embodiments provide a low-cost, low-temperature drift modular Sham optical engine. This optical engine utilizes spherical optical components to achieve highly uniform illumination, eliminating the high mold costs associated with aspherical optical components and achieving low costs. The structural layout of the optical engine reduces the impact of temperature on key components, minimizing thermal drift and improving system accuracy.

[0082] Combine Figure 1 The optical engine may include a light source 10, a light homogenization unit, a digital micromirror device 20 (DMD), and a lens 30. The light source 10 is primarily used for light input. The light homogenization unit, located between the light source 10 and the DMD 20, evens out and deflects light toward the DMD 20. The DMD 20 is used to spatially modulate light to generate images or structured light. The lens 30 is used to project the modulated light onto the surface of a target object.

[0083] The heat sources of an optical engine mainly include the following aspects: ① The heat generated by the light source when converting electricity into light; ② The Joule heat generated by the high-speed flipping of the DMD; ③ The heat generated by the operation of the driving circuit; ④ The heat generated by the optical element absorbing part of the light energy.

[0084] like Figure 1 As shown, the existing optical engine has a compact structure, and the light source part 10 and the lens part 30 are stacked in a direction perpendicular to the optical axis O in the figure, so that the physical distance between the light source part 10 and the lens part 30 is relatively close, and thus the heat of the light source part 10 has a greater impact on the optical elements of the lens part 30.

[0085] To this end, the embodiment of the present disclosure adjusts the position of each module in the optical engine so that there is a gap between the light source module and the projection lens, thereby increasing the physical distance between the light source module and the projection lens, thereby reducing the heat transferred from the light source module to the projection lens, and further reducing the impact of the heat of the light source module on the components in the projection lens, reducing the temperature drift of the optical engine, and improving the detection accuracy of the detection system.

[0086] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0087] Example 1

[0088] Combine Figure 2 and Figure 3The present disclosure provides an optical engine that provides a structured light pattern for a structured light detection system. The optical engine may include a projection lens 100 and an illumination module 200, with the projection lens 100 and the illumination module 200 being fixedly connected. In the present disclosure, the projection lens 100 and the illumination module 200 are separate modules for ease of assembly. The illumination module 200 provides the structured light pattern, and the projection lens 100 projects the structured light pattern onto a target object.

[0089] In the embodiment of the present disclosure, the lighting module 200 includes a light source module 210, a uniform light module 220 and a spatial light modulator 230; the light emitted by the light source module 210 passes through the uniform light module 220 and is emitted to the spatial light modulator 230; the spatial light modulator 230 generates a structured light pattern and projects it onto the target object through the projection lens 100.

[0090] The light homogenization module 220 is used to homogenize and transmit the light generated by the light source module 210. The light source module 210 and the light homogenization module 220 can be detachably connected, so that the light source module 210 can be replaced as needed and the light wavelength range of the optical engine can be flexibly selected.

[0091] In the disclosed embodiment, the spatial light modulator 230 may be a digital micromirror device (DMD), which receives light emitted by the light homogenization module 220 and forms a structured light pattern. The spatial light modulator 230 may also be an LCOS (Liquid Crystal on Silicon).

[0092] The projection lens 100 is a magnifying lens that can magnify the structured light pattern output by the spatial light modulator 230 and project the magnified light pattern onto a target object.

[0093] exist Figure 1 In the structure shown, the light source module 210 emits light in a first direction, and the projection lens 100 emits light in a second direction, which is opposite to the first direction. In this way, through the action of the uniform light module 220, the direction of the light emitted by the light source module 210 is opposite to the direction of the light emitted by the projection lens 100.

[0094] It should be noted that since the light source module 210 and the projection lens 100 include lenses, the lenses can converge or diverge light. In the disclosed embodiment, the light source module 210 emitting light along a first direction means that the light emitted by the light source module 210 along the optical axis is emitted along the first direction. The projection lens 100 emitting light along a second direction means that the light emitted by the projection lens 100 along the optical axis is emitted along the second direction.

[0095] In the embodiment of the present disclosure, the second direction is not opposite to the first direction, which can be understood as the second direction and the first direction are in the same direction, or the second direction and the first direction have an angle therebetween.

[0096] The direction of the light emitted by the light source module 210 is the same as the direction of the light emitted by the projection lens 100, or the direction of the light emitted by the light source module 210 is at an angle to the direction of the light emitted by the projection lens 100. In addition, due to the provision of the uniform light module 220, a gap is created between the light source module 210 and the projection lens 100, thereby expanding the heat transfer distance, thereby reducing the impact of the heat of the light source module 210 on the temperature of the components of the projection lens 100, and thereby reducing the temperature drift of the optical engine.

[0097] Here, the second direction and the first direction are in the same direction, which can be understood in a broad sense as follows: the second direction and the first direction are parallel and in the same direction, or a straight line extending along the second direction and a straight line extending along the first direction are collinear, so that the second direction and the first direction are in the same direction.

[0098] The second direction and the first direction have an included angle, which can be broadly understood as follows: the second direction and the first direction are coplanar, and the second direction and the first direction have an included angle; or the second direction and the first direction are not coplanar, and the second direction and the projection of the first direction have an included angle. The included angle is greater than 0° and less than 180°.

[0099] In some embodiments, combined Figure 4 , the central axis of the projection lens 100 extends along the second direction; the central axis of the light source module 210 extends along the first direction;

[0100] The central axis of the projection lens 100 and the central axis of the light source module 210 are skew lines. Thus, the second direction and the first direction are not in the same plane.

[0101] That is, the central axis of the projection lens 100 is neither intersecting nor parallel to the central axis of the light source module 210. This configuration allows the projection lens 100 to be flexible in its deflection angle and direction relative to the light source module 210.

[0102] In other embodiments, combined Figure 4 and Figure 5 , the central axis of the projection lens 100 and the central axis of the light source module 210 are coplanar straight lines, and the plane defined by the central axis of the projection lens 100 and the central axis of the light source module 210 is the first plane;

[0103] The projection lens 100 and the light source module 210 have a gap in the first plane.

[0104] By arranging the central axis of the projection lens 100 and the central axis of the light source module 210 to be coplanar straight lines, the arrangement of the projection lens 100 and the light source module 210 is simplified, which facilitates the installation of a relatively simple light homogenization module 220 to achieve light deflection and homogenization.

[0105] Since the projection lens 100 and the light source module 210 are two components, the central axis of the projection lens 100 is not collinear with the central axis of the light source module 210. The extension line of the central axis of the projection lens 100 and the extension line of the central axis of the light source module 210 intersect or are parallel. The central axis of the projection lens 100 and the central axis of the light source module 210 define and form a first plane. Figure 3 In the illustrated orientation, the first plane is the XY plane.

[0106] In the embodiment of the present disclosure, Figure 4 The first direction and the second direction are in the same direction. The central axis of the projection lens 100 is parallel to the central axis of the light source module 210, and the first direction and the second direction are in the same direction.

[0107] The angle between the second direction and the first direction can be an acute angle, such as Figure 5 The angle between the second direction and the first direction can be 90°, so that the light direction emitted by the light source module 210 is perpendicular to the light direction emitted by the projection lens 100. The angle between the second direction and the first direction can also be an obtuse angle.

[0108] In the embodiment of the present disclosure, in order to enable the light from the light source module 210 to be emitted to the spatial light modulator 230 via the light homogenization module 220 , a plurality of lenses may be provided to refract the light.

[0109] Combine Figure 4 There is a gap between the projection lens 100 and the light source module 210 , and at least a portion of the light homogenization module 220 is located in the gap to transmit the light from the light source module 210 to the projection lens 100 .

[0110] Since there is a gap between the projection lens 100 and the light source module 210, and the central axis of the projection lens 100 is deflected by a preset angle relative to the central axis of the light source module 210 around the light homogenization module 220, the physical distance between the light source module 210 and the projection lens 100 is increased, and the heat transfer distance is expanded, thereby reducing the impact of the heat of the light source module 210 on the temperature of the components of the projection lens 100 and reducing the temperature drift of the optical engine.

[0111] Therefore, in the optical engine of the embodiment of the present disclosure, the light source module 210 and the projection lens 100 are spaced apart in the first plane, thereby increasing the physical distance between the light source module 210 and the projection lens 100 and expanding the heat transfer distance, thereby reducing the impact of the heat of the light source module 210 on the temperature of the components of the projection lens 100 and reducing the temperature drift of the optical engine.

[0112] Continue to refer to Figure 3 In some embodiments of the present disclosure, there is a gap between the projection lens 100 and the light source module 210 along the extension direction of the central axis of the light source module 210. In addition, the projection lens 100 is located on the light-emitting side of the light source module 210. In this way, the projection lens 100 is close to the light-emitting end of the light source module 210 and is separated from it, while the projection lens 100 is far away from the heat source end of the light source module 210. This further reduces the impact of the heat from the light source module 210 on the components of the projection lens 100, further reduces the temperature drift of the optical engine, and enables the optical engine to have low-temperature drift performance.

[0113] Combine Figure 5 The projection lens 100 is located on the light emitting side of the light source module 210. The central axis of the projection lens 100 may not be parallel to the central axis of the light source module 210, so that the angle between the first direction and the second direction is greater than zero.

[0114] Combine Figure 3 , the extension direction of the central axis of the projection lens 100 is parallel to the extension direction of the central axis of the light source module 210, so that the angle between the second direction and the first direction is equal to 0°. As a result, the projection lens 100 is roughly arranged in a Z shape. Such an arrangement makes the arrangement position of the uniform light module 220 and the spatial light modulator 230 simple, which is convenient for adjusting the light. The interval between the light source module 210 and the projection lens 100 increases the heat conduction distance, and under the same heat dissipation conditions, the temperature of the projection lens 100 is reduced compared with the existing technical structure. Moreover, it is convenient to adjust the inclination angle of the image source surface of the spatial light modulator 230 relative to the optical axis so that the projection lens 100, the image source surface and the plane of the target object satisfy Schaam's law, so that the optical engine can still form a clear image under tilted conditions.

[0115] The light homogenization module 220 and the spatial light modulator 230 are located in the gap between the projection lens 100 and the light source module 210 , making the structure of the optical engine compact and eliminating the need for designing a complex light deflection structure, thereby simplifying the structure of the light homogenization module 220 .

[0116] Combine Figure 6 and Figure 7, the image source plane of the spatial light modulator 230, the principal plane of the projection lens 100, and the extended projection plane of the target object intersect on the same straight line, satisfying Schaam's law;

[0117] The image source plane of the spatial light modulator 230, the main plane of the projection lens 100, and the extended projection plane of the target object intersect on the same straight line, and when the intersection line is unique, a clear projection can be achieved in the entire oblique projection field of view. The following Sham relationship is satisfied:

[0118] tanα / tanβ=b ′ / a ′

[0119] Where α is the angle between the projection plane and the lens optical axis, β is the angle between the image source plane and the lens optical axis, a' is the object distance at point D on the lens optical axis, b' is the image distance at point D on the optical axis, and b' / a' is the lens magnification. The angle β between the DMD chip plane and the lens optical axis needs to satisfy the following relationship:

[0120]

[0121] Where f′ is the focal length of the lens.

[0122] The included angle β between the image source plane and the optical axis may be 80° to 90°.

[0123] The light homogenization module 220 may include a prism 221 and a housing 222. The prism 221 is located in the housing 222 and can be used to redirect and eliminate stray light. The prism 221 may be an RTIR prism 221 or a TIR prism 221.

[0124] In the related art, the prism 221 is fixed to the housing 222 by glue, which is a simple and reliable fixing method. However, taking the housing 222 made of 6061 aluminum alloy as an example, its linear expansion coefficient is 23.6×10 -6 / ℃, that is, when the temperature rises by 10℃, the aluminum alloy expands by 23.6um. Taking the prism 221 made of optical glass BK7 as an example, its thermal expansion coefficient is 7.1×10 -6 / ℃, that is, for every 10℃ rise in temperature, the glass expands 7.1um. In conventional designs, glue is used to fix the prism 221. For example, a certain UV glue has a thermal expansion coefficient of 220×10 -6 / °C, meaning that for every 10°C increase in temperature, the glue expands by 220 μm. Therefore, under the same temperature increase, the displacement of prism 221 is greater than when no glue is used. Therefore, in the disclosed embodiment, prism 221 is secured not with glue but with structural members to reduce temperature drift of the optical engine.

[0125] Continue to refer to Figure 3、 Figure 8 as well as Figure 9 In the embodiment of the present disclosure, the light homogenization module 220 may further include a fixing member 223 , which is fixedly connected to the housing portion 222 and elastically contacts the prism 221 .

[0126] In this way, the fixing member 223 can be used to secure the prism 221 within the housing 222, while also allowing for elastic contact between the fixing member 223 and the prism 221, thereby preventing the fixing member 223 from damaging the prism 221. Compared to securing with glue, using the fixing member 223 to secure the prism 221 minimizes displacement of the prism 221, thereby reducing thermal drift of the optical engine.

[0127] The fixing member 223 can be a screw with an elastic rubber sleeve on its head. The screw is fixedly connected to the housing portion 222, and the elastic rubber sleeve is in elastic contact with the prism 221. The expansion coefficient of the elastic rubber sleeve is smaller than that of the glue, and the expansion of the prism 221 can also be converted into elastic deformation of the elastic rubber sleeve, which helps to reduce temperature drift.

[0128] In some implementations of the present disclosure, fixing member 223 is a spring screw. Using existing spring screws not only provides a stable connection but also reduces costs. Furthermore, the hard contact between the spring screw and prism 221 minimizes deformation due to temperature, further reducing thermal drift. Furthermore, the spring within the spring screw is in a compressed state. When the temperature changes, the expansion of prism 221 is converted into compression of the spring, which not only reduces thermal drift but also ensures the reliability of prism 221's fixation.

[0129] Continue to refer to Figure 8 and Figure 9 In some embodiments of the present disclosure, multiple fixing members 223 may be provided to constrain the prism 221 to a predetermined position. For example, two fixing members 223 are provided, one of which constrains the prism 221's degree of freedom along the horizontal direction H, and the other of which constrains the prism 221's degree of freedom along the vertical direction V. The horizontal direction H may be parallel to the central axis of the projection lens 100.

[0130] The fixing member 223 can be in direct elastic contact with the prism 221 ; the fixing member 223 can also be in elastic contact with the prism 221 through an intermediate member. The intermediate member and the prism 221 can have a larger contact area, thereby improving the installation stability of the prism 221 .

[0131] Continue to refer to Figure 3 In some embodiments of the present disclosure, the light source module 210 includes a light source 211 and a first lens G01, a second lens G02, and a third lens G03 arranged in sequence along the light emission direction of the optical axis.

[0132] The light source 211 may be a monochromatic LED, a polychromatic LED, a laser or an optical fiber.

[0133] The light source 211 and the housing of the light source module 210 can be detachably connected, such as by threaded connection, snap connection or plug-in connection, so as to facilitate the removal and replacement of the light source 211 to adapt to the optical engine's requirements for light of different wavelength bands.

[0134] The light source module 210 of the present embodiment may further include a lens assembly for processing light emitted by the light source 211. The lens assembly may include a first lens G01, a second lens G02, and a third lens G03. The first lens G01, the second lens G02, and the third lens G03 are all mounted within the housing of the light source module 210.

[0135] The light homogenization module 220 includes a light homogenization element G04 , a fourth lens G05 , a reflector G06 , a fifth lens G07 , and a prism 221 , which are sequentially arranged along the optical emission direction of the optical axis.

[0136] The light homogenizing element G04, the fourth lens G05, the reflector G06, the fifth lens G07, and the prism 221 of the light homogenizing module 220 are installed in the housing 222, which is connected to the housing of the light source module 210. The light homogenizing element G04 can be an optical integrator rod, a fly-eye lens, a diffuser, frosted glass, etc.

[0137] The reflector G06 is installed between the fourth lens G05 and the fifth lens G07 to refract light, thereby reducing the volume of the light homogenization module 220 .

[0138] Combine Figure 3 The optical structure shown in the figure is simple in form while ensuring the optical path size and volume of the optical engine. Each lens adopts a spherical lens, which has good processability; moreover, it can also reduce the processing cost.

[0139] In the disclosed embodiment, the first lens G01 is a meniscus lens, the second lens G02 is a meniscus lens, the third lens G03 is a meniscus lens, the fourth lens G05 is a biconvex lens, and the fifth lens G07 is a biconvex lens. The first lens G01 is the lens closest to the light source 211, and the fifth lens G07 is the lens closest to the projection lens 100.

[0140] The curvature radius of each lens is: the curvature radius R011 of the incident surface of the first lens G01 is -25mm to -15mm, and the curvature radius R012 of the exit surface is -10mm to -1mm; the curvature radius R021 of the incident surface of the second lens G02 is -80mm to -70mm, and the curvature radius R022 of the exit surface is -15mm to -5mm; the curvature radius R031 of the incident surface of the third lens G03 is - The radius of curvature of the incident surface of the fourth lens G05 is R051 of 100mm-110mm, and the radius of curvature of the exit surface is R052 of 100mm-110mm; the radius of curvature of the incident surface of the fifth lens G07 is R071 of -40mm--30mm, and the radius of curvature of the exit surface is R072 of 30mm-40mm.

[0141] The focal lengths of the lenses are as follows: the focal length f01 of the first lens G01 is 5 mm to 15 mm; the focal length f02 of the second lens G02 is 10 mm to 20 mm; the focal length f03 of the third lens G03 is -80 mm to -70 mm; the focal length f05 of the fourth lens G05 is 60 mm to 70 mm; and the focal length f07 of the fifth lens G07 is -25 mm to -15 mm.

[0142] For example, the focal length f01 of the first lens G01 is 7.2229 mm; the focal length f02 of the second lens G02 is 11.6573 mm; the focal length f03 of the third lens G03 is -75.0402 mm; the focal length f05 of the fourth lens G05 is 65.948 mm; and the focal length f07 of the fifth lens G07 is -21.314 mm.

[0143] In some embodiments, the focal length f01 of the first lens G01 and the effective focal length f of the projection lens 100 satisfy 0<|f01 / f|<1; the focal length f02 of the second lens G02 and the effective focal length f of the projection lens 100 satisfy 0.5<|f02 / f|<1.5; the focal length f03 of the third lens G03 and the effective focal length f of the projection lens 100 satisfy 2<|f03 / f|<4; the focal length f05 of the fourth lens G05 and the effective focal length f of the projection lens 100 satisfy 2<|f05 / f|<4; the focal length f07 of the fifth lens G07 and the effective focal length f of the projection lens 100 satisfy 0.5<|f07 / f|<1.5.

[0144] The optical material parameters of each lens are as follows: the refractive index N01 of the first lens G01 is 1.7-1.9, and the Abbe number V01 is 20-25; the refractive index N02 of the second lens G02 is 1.7-1.9, and the Abbe number V02 is 45-50; the refractive index N03 of the third lens G03 is 1.7-1.9, and the Abbe number V03 is 45-50; the refractive index N05 of the fourth lens G05 is 1.7-1.9, and the Abbe number V04 is 45-50; the refractive index N07 of the fifth lens G07 is 1.7-1.9, and the Abbe number V05 is 45-50.

[0145] The center thickness of each lens is: the center thickness GT01 of the first lens G01 is 3mm to 6mm; the center thickness GT02 of the second lens G02 is 2mm to 6mm;

[0146] The center thickness GT03 of the third lens G03 is 1 mm to 4 mm; the center thickness GT05 of the fourth lens G05 is 1 mm to 4 mm; and the center thickness GT07 of the fifth lens G07 is 3 mm to 6 mm.

[0147] In some implementations, the air spacing distance AT00 between the light source 211 and the first lens G01 along the optical axis is 0 mm to 2 mm; the air spacing distance AT01 between the first lens G01 and the second lens G02 along the optical axis is 0 mm to 2 mm; the air spacing distance AT02 between the second lens G02 and the third lens G03 along the optical axis is 0 mm to 2 mm; the air spacing distance AT03 between the third lens G03 and the light homogenizing element G04 along the optical axis is 1 mm to 4 mm; the air spacing distance AT04 between the light homogenizing element G04 and the fourth lens G05 along the optical axis is 1 mm to 4 mm. The air spacing distance AT04 along the optical axis is 1mm~3mm; the air spacing distance AT05 between the center of the fourth lens G05 and the reflector G06 along the optical axis is 8mm~11mm; the air spacing distance AT06 between the center of the reflector G06 and the fifth lens G07 along the optical axis is 9mm~12mm; the air spacing distance AT07 between the fifth lens G07 and the prism 221 along the optical axis is 3mm~7mm; the air spacing distance AT08 between the prism 221 and the image source surface of the spatial light modulator 230 along the optical axis is 0mm~2mm.

[0148] In the embodiment of the present disclosure, the focal length of the projection imaging system is 8 mm to 14 mm, for example, 8 mm to 9 mm, 8.5 mm to 14 mm, etc. The distance from the projection surface to the main surface of the imaging system is 250 mm to 350 mm.

[0149] This patent describes a low-temperature drifted oblique-axis optical engine with an operating F-number range of F / 1.7 to F / 4.2, such as F / 3.8 to F / 4.2 and F / 1.7 to F / 4. It is suitable for LEDs with a light-emitting surface size of 0.5 to 2.5 mm, an operating wavelength range of 390 nm to 700 nm, such as 400 nm to 700 nm, and an operating distance range of 100 to 150 mm.

[0150] Through the above-mentioned arrangement, the optical engine of the embodiment of the present disclosure expands the heat conduction distance by spacing the light source module 210 and the projection lens 100, and uses a mechanical fixing member 223 to fix the prism 221 instead of using glue to fix the prism 221, which is beneficial to reducing the temperature drift of the optical engine; and the lens uses a spherical lens, which is beneficial to reducing costs; thereby, the optical engine achieves the characteristics of low cost and low temperature drift.

[0151] Combine Figure 10 In the thermal analysis image of the optical engine in the prior art, the temperature of the light source part is the highest and gradually spreads to the uniform light part. Figure 10 It can be seen that a large amount of heat has been transferred to the lens of the projection lens (some lenses are shown in orange in the figure), which has a significant impact on the temperature drift of the projection lens.

[0152] Combine Figure 11 In the thermal analysis image of the optical engine of the embodiment of the present disclosure, the entire projection lens is shown in yellow, and part of the projection lens is shown in green. The temperature of the light source module has little effect on the projection lens, which helps to reduce the temperature drift of the projection lens.

[0153] Example 2

[0154] Combine Figure 12 An embodiment of the present disclosure provides a projection lens, which includes: at least four lens groups and an aperture stop ST arranged in sequence along an optical axis O.

[0155] Each lens group includes at least one lens. Each lens group can include a pair of separate lenses or a cemented lens. The lenses in each lens group can be all spherical lenses, all aspherical lenses, or a combination of spherical and aspherical lenses.

[0156] Lenses are made of colorless optical glass or optical plastic. Optical plastic offers low mass production costs, easy processing of aspheric surfaces, and lightweight properties. Optical glass possesses stable mechanical and thermal properties, and by combining different refractive indices and Abbe numbers, chromatic aberration can be eliminated, improving image quality. Industrial robots operate in diverse environments and require high ambient temperature stability.

[0157] In some embodiments, all lenses of the projection lens are made entirely of glass, and all lenses are spherical lenses. First, glass has higher transmittance and better imaging quality than plastic. Second, glass is far more physically and chemically stable than plastic, better adaptable to various environments and longer-lasting. Furthermore, glass spherical lenses are significantly less expensive than glass aspherical lenses.

[0158] At least two lens groups are provided on the side of the aperture stop ST facing the projection surface, and at least two lens groups are provided on the side of the aperture stop ST facing the image source surface 12; wherein, the projection surface is used to receive the projection picture; the image source surface 12 is used to output the image to be projected.

[0159] When the projection lens projects onto the surface of the target object, the target object surface serves as the surface receiving the projected image, i.e., the projection surface. The image source surface 12 is the chip plane of the spatial light modulator. Light is projected from the image source surface 12 to the projection surface.

[0160] The at least four lens groups include a first lens group L1, a second lens group L2, a third lens group L3, and a fourth lens group L4. The second lens group L2 is located on a side of the aperture stop ST facing the projection plane and is close to the aperture stop ST. The first lens group L1 is located on a side of the second lens group L2 facing the projection plane. The third lens group L3 is located on a side of the aperture stop ST facing the image source plane 12 and is close to the aperture stop ST. The fourth lens group L4 is located on a side of the third lens group L3 facing the image source plane 12.

[0161] Taking the projection lens as an example, which includes four lens groups, along the optical axis O, in the direction from the image source plane 12 to the projection plane, that is, along the direction from the light emission along the optical axis O, the first lens group L1, the second lens group L2, the aperture stop ST, the third lens group L3 and the fourth lens group L4 are arranged in order.

[0162] The refractive power of the first lens group L1 is negative, the refractive power of the second lens group L2 is positive, the refractive power of the third lens group L3 is negative, and the refractive power of the fourth lens group L4 is positive.

[0163] Among them, along the optical axis from the projection plane to the image source plane 12, the optical focal length of the first lens group L1 is negative, which can allow light beams with a large off-axis angle to enter the lens; the optical focal length of the second lens group L2 is positive, which can achieve the deflection of the light angle, allowing the light to smoothly enter the aperture stop ST; the optical focal length of the third lens group L3 is negative, which receives the light emitted by the aperture stop ST, making the light trend more gentle; the optical focal length of the fourth lens group L4 is positive, and has a certain convergence ability, allowing the light to converge on the image source plane.

[0164] Along the direction of light emission, the fourth lens group L4 has a positive optical power and has a certain convergence ability, which can collect the light projected from the image source surface 12; the third lens group L3 has a negative optical power and receives the light emitted by the fourth lens group L4 and enters the aperture; the second lens group L2 has a positive optical power and converges the light emitted from the aperture stop ST; the first lens group L1 has a negative optical power and can diffuse the light outward and project it onto the corresponding object surface.

[0165] Combine Figure 6 and Figure 7 The image source plane 12 of the projection lens is arranged perpendicularly or obliquely relative to the optical axis O. The angle θ between the normal direction N of the image source plane of the projection lens and the optical axis is 0° to 10°. The angle θ and the angle β are complementary angles, that is, the sum of the angles θ and β is 90°.

[0166] When the image source plane 12 of the projection lens is perpendicular to the optical axis O, the normal direction N of the image source plane 12 is parallel to the optical axis, so that the angle θ between the normal direction N of the image source plane and the optical axis O is 0°.

[0167] When the image source surface 12 of the projection lens is tilted relative to the optical axis O, an angle θ is formed between the normal direction N of the image source surface 12 and the optical axis O. The angle θ is greater than 0° and less than or equal to 10°.

[0168] Therefore, the projection lens of the embodiment of the present disclosure can project clearly when the image source plane is perpendicular to the optical axis, and can also project clearly when the image source plane is tilted relative to the optical axis. The projection lens has the characteristics of high resolution, compact structure and low cost.

[0169] In the embodiment of the present disclosure, the effective focal length f of the projection lens is 8.5 mm to 14 mm, the aperture number Fno is F / 1.7 to F / 4, the size IMG of the digital micromirror device (DMD) adapted for the projection lens is 8 mm to 12 mm, the operating band is 390 nm to 700 nm, the total system optical length TTL of the projection lens is 50 mm to 85 mm, and the system back focus BFL is greater than 10 mm, for example, the system back focus BFL is 17.5 mm to 21.4 mm.

[0170] The focal length fa of the first lens group L1 is -26.5mm to -12.4mm, the focal length fb of the second lens group L2 is 16.5mm to 25.3mm, the focal length fc of the third lens group L3 is -95mm to -45mm, and the focal length fd of the fourth lens group L4 is 10mm to 14mm.

[0171] The axial distance d12 between the first lens group L1 and the second lens group L2 is 0.2 mm to 7.3 mm, the axial distance d23 between the second lens group L2 and the third lens group L3 is 2.9 mm to 11.9 mm, and the axial distance d34 between the third lens group L3 and the fourth lens group L4 is 1.8 mm to 2.9 mm.

[0172] The focal length fa of the first lens group L1 satisfies |fa / f|=1.4~1.9 with the effective focal length f of the projection lens, the focal length fb of the second lens group L2 satisfies fb / f=1.2~2.4 with the effective focal length f of the projection lens, the focal length fc of the third lens group L3 satisfies |fc / f|=3.2~8.7 with the effective focal length f of the projection lens, and the focal length fd of the fourth lens group L4 satisfies fd / f=0.7~1.3 with the effective focal length f of the projection lens.

[0173] The following combination Figures 13 to 15 The performance of the projection lens of the embodiment of the present disclosure is described. Figure 13 A distortion diagram of the projection lens provided in an embodiment of the present disclosure; Figure 14 An MTF curve diagram of the projection lens provided in an embodiment of the present disclosure; Figure 15 A relative illumination curve diagram of the projection lens provided in an embodiment of the present disclosure.

[0174] exist Figure 13 In the distortion diagram, the vertical axis is the field of view and the horizontal axis is the distortion value. Each curve represents the distortion value at different wavelengths within the working band. Figure 13 The distortion curve of the projection lens of the disclosed embodiment exhibits a monotonic variation across the entire field of view. From the center field of view of 0° to the edge field of view of 15.94°, the distortion gradually increases from 0 to 5%, showing a monotonic variation. Compared to a non-monotonic distortion curve, a monotonic distortion curve simplifies the correction process during 3D reconstruction. The algorithm can more accurately compensate for distortion, reduce errors, and achieve higher fitting accuracy, thereby achieving higher detection precision.

[0175] In some possible embodiments, the distortion of the projection lens is less than 5%, so that the full-frame distortion of the imaging is small.

[0176] like Figure 14The MTF (Modulation Transfer Function) curve shown in the figure has the spatial frequency on the horizontal axis in line cycles / mm and the contrast on the vertical axis in the range of 0-1. The solid and dashed lines represent the meridional and sagittal components of the MTF under different fields of view. The solid line represents the contrast component in the meridional direction, which is perpendicular to the optical axis; the dashed line represents the contrast component in the sagittal direction, which is along the optical axis. The higher the two curves are and the closer they are to each other, the higher the imaging quality. Figure 14 The contrast ratio of the MTF of each field of view of the projection lens at a spatial frequency of 93 cycles / mm is greater than 0.7, which can achieve high-resolution imaging, reduce image blur, make the image clearer, and improve image quality.

[0177] Figure 15 In the relative illumination curve, the horizontal axis is the field of view, and the unit is mm. Among them, 0 is the center field of view, and 3.96mm represents the edge field of view. The vertical axis is the relative illumination, and the value range is 0 to 1. The projection lens of the disclosed embodiment has a relative illumination of 100% in the center field of view, and a relative illumination of greater than 96% in the edge field of view. The edge field of view has a high relative illumination, which can ensure the uniformity of the entire picture. There will be no dark corners even at the edge of the picture, and the difference between the edge brightness and the center brightness is small, reducing the need for post-brightness correction.

[0178] Example 3

[0179] Combine Figure 16 , the projection lens of this embodiment is composed of eight lenses.

[0180] The projection lens includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a fifth lens G5, a sixth lens G6, a seventh lens G7 and an eighth lens G8 along the optical axis from the projection plane to the image source plane. The first lens G1, the second lens G2 and the third lens G3 form a first lens group L1; the fourth lens G4 forms a second lens group L2, the fifth lens G5 forms a third lens group L3, and the sixth lens G6, the seventh lens G7 and the eighth lens G8 form a fourth lens group L4.

[0181] Among them, the first lens G1 is a convex-plano lens with positive focal power, the second lens G2 is a convex-concave lens with negative focal power, the third lens G3 is a meniscus lens with negative focal power, the fourth lens G4 is a meniscus lens with positive focal power, the fifth lens G5 is a convex-concave lens with negative focal power, the sixth lens G6 is a biconcave lens with negative focal power, the seventh lens G7 is a biconvex lens with positive focal power, the sixth lens G6 and the seventh lens G7 are a cemented lens, and the eighth lens G8 is a biconvex lens with positive focal power.

[0182] The first lens G1 has positive optical power, and its primary function is to provide significant negative distortion, thereby compensating for the significant positive distortion produced by the other lenses. The second and third lenses G2 and G3 have negative optical power, and their primary function is to collect large-angle off-axis light beams and direct them into the lens, thereby miniaturizing the optical path. The fourth lens G4 has positive optical power, and its primary function is to deflect the angle of the light beams, allowing them to smoothly enter the aperture stop ST. The fifth lens G5, located after the aperture stop ST, has negative optical power and receives the light emitted from the aperture stop ST, smoothing its trajectory. The cemented lens consisting of the sixth and seventh lenses G6 and G7 has positive optical power, sharing a certain amount of optical power with the subsequent lenses. The positive lens can adopt a lens with specific DN / DT parameters for athermalization. The eighth lens G8 has positive optical power and provides a certain degree of convergence capability, converging the light onto the image source plane, and can also adopt a lens with specific DN / DT parameters for athermalization.

[0183] Wherein, DN / DT represents the rate of change of the refractive index with temperature (Refractive Index Temperature Coefficient). DN / DT is equal to the ratio between the change in refractive index and the change in temperature.

[0184] The projection lens of the disclosed embodiment has a simple lens structure and good processability while ensuring the size and volume of the lens optical path.

[0185] In the disclosed embodiment, the radius of curvature R11 of the projection-side surface of the first lens element G1 is between 18.6 mm and 32.1 mm, and the radius of curvature R12 of the image-source-side surface is greater than or equal to 110.8 mm. The radius of curvature R21 of the projection-side surface of the second lens element G2 is between 10.1 mm and 18.8 mm, and the radius of curvature R22 of the image-source-side surface is between 4.2 mm and 10.2 mm. The radius of curvature R31 of the projection-side surface of the third lens element G3 is between -68 mm and -6.8 mm, and the radius of curvature R32 of the image-source-side surface is between -16.2 mm and 13.7 mm. The radius of curvature R41 of the projection-side surface of the fourth lens element G4 is between -34 mm and 55.5 mm, and the radius of curvature R42 of the image-source-side surface is between -39.6 mm and -10. 3mm; the radius of curvature R51 of the projection-side surface of the fifth lens element G5 is 16.36mm-43mm, and the radius of curvature R52 of the image-source-side surface is 10.4mm-26.2mm; the radius of curvature R61 of the projection-side surface of the sixth lens element G6 is -76.2mm--18.2mm, and the radius of curvature R62 of the image-source-side surface is 30.7mm-39mm; the radius of curvature R71 of the projection-side surface of the seventh lens element G7 is 30.7mm-39mm, and the radius of curvature R72 of the image-source-side surface is -29.4mm--9.8mm; the radius of curvature R81 of the projection-side surface of the eighth lens element G8 is 19.82mm-48.7mm, and the radius of curvature R82 of the image-source-side surface is -50.3mm--25.74mm;

[0186] The projection side surface faces the projection surface, and the image source side surface faces the image source surface.

[0187] In the disclosed embodiment, the center thickness GT1 of the first lens G1 is 3 mm to 5.1 mm; the center thickness GT2 of the second lens G2 is 3 mm to 4 mm; the center thickness GT3 of the third lens G3 is 1.5 mm to 3 mm; the center thickness GT4 of the fourth lens G4 is 1.6 mm to 2.5 mm; the center thickness GT5 of the fifth lens G5 is 3 mm to 5.2 mm; the center thickness GT6 of the sixth lens G6 is 1.5 mm to 2.3 mm; the center thickness GT7 of the seventh lens G7 is 3 mm to 5.1 mm; and the center thickness GT8 of the eighth lens G8 is 3 mm to 4.8 mm. The center thickness of a lens refers to the thickness of the center of the lens along the optical axis.

[0188] In the embodiment of the present disclosure, the air distance AT1 between the first lens G1 and the second lens G2 along the optical axis is 0.2 mm to 2.2 mm; the air distance AT2 between the second lens G2 and the third lens G3 along the optical axis is 2.2 mm to 4.5 mm; the air distance AT3 between the third lens G3 and the fourth lens G4 along the optical axis is 0.2 mm to 7.3 mm; the air distance AT4 between the fourth lens G4 and the aperture stop ST along the optical axis is 0.6 mm to 8.5 mm; the air distance AT5 between the aperture stop ST and the fifth lens G5 along the optical axis is 1.2 mm to 3.4 mm; the air distance AT6 between the fifth lens G5 and the sixth lens G6 along the optical axis is 1.8 mm to 2.9 mm; the sixth lens G6 and the seventh lens G7 are a cemented lens; and the air distance AT7 between the seventh lens G7 and the eighth lens G8 along the optical axis is 0.2 mm to 1.38 mm.

[0189] An air distance AT4 between the fourth lens G4 and the aperture stop ST along the optical axis and an air distance AT5 between the aperture stop ST and the fifth lens G5 along the optical axis satisfy AT4+AT5 of 1.8 mm to 11.9 mm.

[0190] In the disclosed embodiment, the focal length f1 of the first lens G1 is 25 mm to 48 mm; the focal length f2 of the second lens G2 is -33 mm to -13 mm; the focal length f3 of the third lens G3 is -19 mm to -13 mm; the focal length f4 of the fourth lens G4 is 17 mm to 25 mm; the focal length f5 of the fifth lens G5 is -95 mm to -46 mm; the focal length f6 of the sixth lens G6 is -23 mm to -15 mm; the focal length f7 of the seventh lens G7 is 13 mm to 20.6 mm; and the focal length f8 of the eighth lens G8 is 15 mm to 27.6 mm.

[0191] In the disclosed embodiment, the refractive index N1 of the first lens G1 is 1.73 to 1.88, and the Abbe number V1 is 39.2 to 54.7; the refractive index N2 of the second lens G2 is 1.52 to 1.9, and the Abbe number V2 is 31.3 to 58.6; the refractive index N3 of the third lens G3 is 1.7 to 1.85, and the Abbe number V3 is 30 to 52.3; the refractive index N4 of the fourth lens G4 is 1.83 to 1.85, and the Abbe number V4 is 23.8 to 42. .7; the refractive index N5 of the fifth lens G5 is 1.73-1.78, and the Abbe number V5 is 25.7-28.3; the refractive index N6 of the sixth lens G6 is 1.76-1.95, and the Abbe number V6 is 17.9-26.6; the refractive index N7 of the seventh lens G7 is 1.62-1.83, and the Abbe number V7 is 42.7-63.4; the refractive index N8 of the eighth lens G8 is 1.75-1.88, and the Abbe number V8 is 39.2-52.3. The disclosed embodiments define the material properties of each lens by limiting the refractive index and Abbe number of each lens.

[0192] The parameters of each lens in this embodiment can be calculated using optical design software or through a ray tracing algorithm, but the present disclosure does not limit the design tools and design process.

[0193] Each lens or lens group in the optical lens disclosed herein has its own unique functional focus. Through reasonable optical focal length distribution and material matching, various aberrations are balanced and kept within a range that does not affect accuracy.

[0194] Combine Figure 12 The center thickness GT10 of the equivalent prism 10 is 13 mm. The distance between the equivalent prism 10 and the image plane 12 along the optical axis is 2.4 mm, and there is a cover glass 11 with a center thickness of 1.1 mm.

[0195] Combine Figure 5 and Figure 12 The equivalent prism 10 may be at least a portion of the prism 221 , that is, the portion of the prism 221 between the light source surface 12 and the projection lens.

[0196] Example 1:

[0197] The effective focal length f of the projection lens of the embodiment of the present disclosure is 14 mm, the aperture number Fno is F / 4, the DMD size IMG is 8 mm, the operating band is 435 nm to 485 nm, the system optical total length TTL of the projection lens is 50 mm, the system back focus BFL is 17.5 mm, and the angle between the normal direction of the image source surface and the optical axis is 3.3°.

[0198] The focal length fa of first lens group L1 is -26.5mm, the focal length fb of second lens group L2 is 16.5mm, the focal length fc of third lens group L3 is -45mm, and the focal length fd of fourth lens group L4 is 10mm. The axial distance d12 between first lens group L1 and second lens group L2 is 0.2mm, the axial distance d23 between second lens group L2 and third lens group L3 is 2.9mm, and the axial distance d34 between third lens group L3 and fourth lens group L4 is 1.8mm.

[0199] The focal length fa of the first lens group L1 satisfies |fa / f|=1.9 with the effective focal length f of the projection lens, the focal length fb of the second lens group L2 satisfies fb / f=1.2 with the effective focal length f of the projection lens, the focal length fc of the third lens group L3 satisfies |fc / f|=3.2 with the effective focal length f of the projection lens, and the focal length fd of the fourth lens group L4 satisfies fd / f=0.7 with the effective focal length f of the projection lens.

[0200] The curvature radii of each lens are as follows: the curvature radius R11 of the projection side surface of the first lens G1 is 18.6mm, and the curvature radius R12 of the image source side surface is infinite; the curvature radius R21 of the projection side surface of the second lens G2 is 10.1mm, and the curvature radius R22 of the image source side surface is 4.2mm; the curvature radius R31 of the projection side surface of the third lens G3 is -6.8mm, and the curvature radius R32 of the image source side surface is -16.2mm; the curvature radius R41 of the projection side surface of the fourth lens G4 is -34mm, and the curvature radius R42 of the image source side surface is -10 .3mm; the radius of curvature R51 of the projection-side surface of the fifth lens element G5 is 16.36mm, and the radius of curvature R52 of the image-source-side surface is 10.4mm; the radius of curvature R61 of the projection-side surface of the sixth lens element G6 is -18.2mm, and the radius of curvature R62 of the image-source-side surface is 39mm; the radius of curvature R71 of the projection-side surface of the seventh lens element G7 is 39mm, and the radius of curvature R72 of the image-source-side surface is -9.8mm; the radius of curvature R81 of the projection-side surface of the eighth lens element G8 is 19.82mm, and the radius of curvature R82 of the image-source-side surface is -25.74mm.

[0201] The center thicknesses of the lenses are as follows: the center thickness GT1 of the first lens G1 is 3 mm; the center thickness GT2 of the second lens G2 is 3 mm; the center thickness GT3 of the third lens G3 is 3 mm; the center thickness GT4 of the fourth lens G4 is 1.6 mm; the center thickness GT5 of the fifth lens G5 is 3 mm; the center thickness GT6 of the sixth lens G6 is 2.3 mm; the center thickness GT7 of the seventh lens G7 is 3 mm; the center thickness GT8 of the eighth lens G8 is 3 mm, and the center thickness GT10 of the equivalent prism 10 is 13 mm.

[0202] The air spacing between the lenses is as follows: the air spacing distance AT1 along the optical axis between the first lens G1 and the second lens G2 is 2.2 mm; the air spacing distance AT2 along the optical axis between the second lens G2 and the third lens G3 is 2.2 mm; the air spacing distance AT3 along the optical axis between the third lens G3 and the fourth lens G4 is 0.2 mm; the air spacing distance AT4 along the optical axis between the fourth lens G4 and the aperture stop ST is 0.6 mm; the air spacing distance AT5 along the optical axis between the aperture stop ST and the fifth lens G5 is 2.3 mm; the air spacing distance AT6 along the optical axis between the fifth lens G5 and the sixth lens G6 is 1.8 mm; the sixth lens G6 and the seventh lens G7 are a cemented lens; the air spacing distance AT7 along the optical axis between the seventh lens G7 and the eighth lens G8 is 1.14 mm; and the air spacing distance along the optical axis between the eighth lens G8 and the equivalent prism 10 is 2.3 mm.

[0203] An air distance AT4 between the fourth lens G4 and the aperture stop ST along the optical axis and an air distance AT5 between the aperture stop ST and the fifth lens G5 along the optical axis satisfy AT4+AT5=2.9 mm.

[0204] The focal lengths of the lenses are as follows: the focal length f1 of the first lens G1 is 25 mm; the focal length f2 of the second lens G2 is -17 mm; the focal length f3 of the third lens G3 is -19 mm; the focal length f4 of the fourth lens G4 is 17 mm; the focal length f5 of the fifth lens G5 is -46 mm; the focal length f6 of the sixth lens G6 is -15 mm; the focal length f7 of the seventh lens G7 is 13 mm; and the focal length f8 of the eighth lens G8 is 15 mm.

[0205] The optical material parameters of each lens are as follows: the refractive index N1 of the first lens element G1 is 1.73, and the Abbe number V1 is 54.7; the refractive index N2 of the second lens element G2 is 1.52, and the Abbe number V2 is 58.6; the refractive index N3 of the third lens element G3 is 1.7, and the Abbe number V3 is 30; the refractive index N4 of the fourth lens element G4 is 1.83, and the Abbe number V4 is 42.7; the refractive index N5 of the fifth lens element G5 is 1.78, and the Abbe number V5 is 25.7; the refractive index N6 of the sixth lens element G6 is 1.76, and the Abbe number V6 is 26.6; the refractive index N7 of the seventh lens element G7 is 1.62, and the Abbe number V7 is 63.4; the refractive index N8 of the eighth lens element G8 is 1.75, and the Abbe number V8 is 52.3; and the refractive index N10 of the equivalent prism 10 is 1.71, and the Abbe number V10 is 53.8.

[0206] Example 4

[0207] While meeting overall optical performance requirements, some embodiments may include one or more optional lenses between two adjacent lenses to further improve aberrations, control beam quality, optimize projection magnification, or adapt to different application scenarios. These optional lenses can be spherical or aspherical, with positive or negative optical power, and their material, surface shape, thickness, and position can be adjusted as needed. The introduction of optional lenses does not alter the basic structure and core design concept of the disclosed projection lens.

[0208] Combine Figure 17 , the projection lens of this embodiment is composed of nine lenses.

[0209] The projection lens includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a fifth lens G5, a sixth lens G6, a seventh lens G7, an eighth lens G8, and a ninth lens G9 along the optical axis from the projection plane to the image source plane. The first lens G1 forms a first lens group L1; the second lens G2, the third lens G3, and the fourth lens G4 form a second lens group L2; the fifth lens G5 forms a third lens group L3; and the sixth lens G6, the seventh lens G7, the eighth lens G8, and the ninth lens G9 form a fourth lens group L4.

[0210] Among them, the first lens G1 is a convex-plano lens or a convex-concave lens with positive focal power, the second lens G2 is a convex-concave lens with negative focal power, the third lens G3 is a convex-convex lens or a plano-concave lens or a biconcave lens with negative focal power, the fourth lens G4 is a convex-convex lens or a biconvex lens with positive focal power, the fifth lens G5 is a convex-concave lens with negative focal power, the sixth lens G6 is a biconcave lens with negative focal power, the seventh lens G7 is a biconvex lens with positive focal power, the eighth lens G8 is a biconvex lens with positive focal power, and the ninth lens G9 is a convex-plano lens or a convex-concave lens with positive focal power.

[0211] In the embodiment of the present disclosure, the curvature radius, center thickness, air spacing distance, focal length, refractive index and Abbe number of the first to eighth lenses can refer to the above-mentioned embodiment 2.

[0212] The curvature radius R91 of the projection-side surface of the ninth lens G9 is 19.7 mm to 24.4 mm, and the curvature radius R92 of the image-source-side surface is greater than or equal to 221.5 mm.

[0213] The center thickness GT9 of the ninth lens G9 is 4 mm to 5.2 mm;

[0214] The air distance AT8 between the eighth lens G8 and the ninth lens G9 along the optical axis is 0.2 mm;

[0215] The focal length f9 of the ninth lens element G9 is 34 mm to 43.1 mm.

[0216] The refractive index N8 of the ninth lens G9 is 1.57 to 1.62, and the Abbe number V8 is 60.3 to 71.3.

[0217] The air distance between the ninth lens G9 and the equivalent prism 10 along the optical axis is 2.3 mm to 6.2 mm.

[0218] Example 2:

[0219] The effective focal length f of the projection lens of the embodiment of the present disclosure is 8.5 mm, the aperture number Fno is F / 1.7, the image DMD size IIMG is 8 mm, the operating band is 435 nm to 485 nm, the system optical total length TTL of the projection lens is 65 mm, the system back focus BFL is 18.2 mm, and the angle between the normal direction of the image source surface and the optical axis is 10°.

[0220] The focal length fa of first lens group L1 is -12.4 mm, the focal length fb of second lens group L2 is 20.3 mm, the focal length fc of third lens group L3 is -69.5 mm, and the focal length fd of fourth lens group L4 is 11 mm. The axial distance d12 between first lens group L1 and second lens group L2 is 5.7 mm, the axial distance d23 between second lens group L2 and third lens group L3 is 6.3 mm, and the axial distance d34 between third lens group L3 and fourth lens group L4 is 2.5 mm.

[0221] The focal length fa of the first lens group L1 satisfies |fa / f|=1.5 with the effective focal length f of the projection lens, the focal length fb of the second lens group L2 satisfies fb / f=2.4 with the effective focal length f of the projection lens, the focal length fc of the third lens group L3 satisfies |fc / f|=8.2 with the effective focal length f of the projection lens, and the focal length fd of the fourth lens group L4 satisfies fd / f=1.3 with the effective focal length f of the projection lens.

[0222] The first lens G1 is a convex-concave lens, the second lens G2 is a convex-concave lens, the third lens G3 is a plano-concave lens, the fourth lens G4 is a biconvex lens, the fifth lens G5 is a convex-concave lens, the sixth lens G6 is a biconcave lens, the seventh lens G7 is a biconvex lens, the eighth lens G8 is a biconvex lens, and the ninth lens G9 is a convex-plano lens.

[0223] The curvature radii of each lens are as follows: the curvature radius R11 of the projection side surface of the first lens G1 is 27mm, and the curvature radius R12 of the image source side surface is 83.6; the curvature radius R21 of the projection side surface of the second lens G2 is 15.7mm, and the curvature radius R22 of the image source side surface is 8.4mm; the curvature radius R31 of the projection side surface of the third lens G3 is infinite, and the curvature radius R32 of the image source side surface is 10.2mm; the curvature radius R41 of the projection side surface of the fourth lens G4 is 31.7mm, and the curvature radius R42 of the image source side surface is -39.6mm; the curvature radius R51 of the projection side surface of the fifth lens G5 is The radius of curvature R61 of the projection-side surface of the sixth lens element G6 is -32.5 mm, and the radius of curvature R62 of the image-source-side surface is 30.7 mm. The radius of curvature R71 of the projection-side surface of the seventh lens element G7 is 30.7 mm, and the radius of curvature R72 of the image-source-side surface is -18.2 mm. The radius of curvature R81 of the projection-side surface of the eighth lens element G8 is 40.4 mm, and the radius of curvature R82 of the image-source-side surface is -50.3 mm. The radius of curvature R91 of the projection-side surface of the ninth lens element G9 is 19.7 mm, and the radius of curvature R82 of the image-source-side surface is infinite.

[0224] The center thicknesses of the lenses are as follows: the center thickness GT1 of the first lens G1 is 3.9 mm; the center thickness GT2 of the second lens G2 is 3 mm; the center thickness GT3 of the third lens G3 is 1.5 mm; the center thickness GT4 of the fourth lens G4 is 2.3 mm; the center thickness GT5 of the fifth lens G5 is 3.7 mm; the center thickness GT6 of the sixth lens G6 is 1.5 mm; the center thickness GT7 of the seventh lens G7 is 4.5 mm; the center thickness GT8 of the eighth lens G8 is 3 mm; the center thickness GT9 of the ninth lens G9 is 4 mm; and the center thickness GT10 of the equivalent prism 10 is 13 mm.

[0225] The air spacing between the lenses is as follows: the air spacing distance AT1 between the first lens G1 and the second lens G2 along the optical axis is 0.2 mm; the air spacing distance AT2 between the second lens G2 and the third lens G3 along the optical axis is 4 mm; the air spacing distance AT3 between the third lens G3 and the fourth lens G4 along the optical axis is 5.7 mm; the air spacing distance AT4 between the fourth lens G4 and the aperture stop ST along the optical axis is 5.2 mm; the air spacing distance AT5 between the aperture stop ST and the fifth lens G5 along the optical axis is 1.2 mm; the air spacing distance AT5 between the fifth lens G5 and the sixth lens G4 along the optical axis is 1.2 mm; the air spacing distance AT6 between the fifth lens G5 and the sixth lens G4 along the optical axis is 1.2 mm; the air spacing distance AT7 between the fifth lens G5 and the sixth lens G4 along the optical axis is 1.2 mm; the air spacing distance AT8 between the fifth lens G5 and the sixth lens G4 along the optical axis is 1.2 mm; the air spacing distance AT9 between the fifth lens G5 and the sixth lens G4 along the optical axis is 1.2 mm; the air spacing distance AT1 .... The air spacing distance AT6 of lens G6 along the optical axis is 2.4 mm; the sixth lens G6 and the seventh lens G7 are a cemented lens; the air spacing distance AT7 of the seventh lens G7 and the eighth lens G8 along the optical axis is 0.2 mm; the air spacing distance AT8 of the eighth lens G8 and the ninth lens G9 along the optical axis is 0.2 mm; the air spacing distance of the ninth lens G9 and the equivalent prism 10 along the optical axis is 2.45 mm, and the distance between the equivalent prism 10 and the image plane 12 along the optical axis is 2.2 mm. There is a cover glass 11 with a center thickness of 1.1 mm.

[0226] An air distance AT4 between the fourth lens G4 and the aperture stop ST along the optical axis and an air distance AT5 between the aperture stop ST and the fifth lens G5 along the optical axis satisfy AT4+AT5=6.4 mm.

[0227] The focal lengths of the lenses are as follows: the focal length f1 of the first lens G1 is 48 mm; the focal length f2 of the second lens G2 is -24 mm; the focal length f3 of the third lens G3 is -13 mm; the focal length f4 of the fourth lens G4 is 20 mm; the focal length f5 of the fifth lens G5 is -69 mm; the focal length f6 of the sixth lens G6 is -16 mm; the focal length f7 of the seventh lens G7 is 14 mm; the focal length f8 of the eighth lens G8 is 25 mm; and the focal length f9 of the ninth lens G9 is 34 mm.

[0228] The optical material parameters of each lens are as follows: the refractive index N1 of the first lens G1 is 1.79, and the Abbe number V1 is 47.5; the refractive index N2 of the second lens G2 is 1.9, and the Abbe number V2 is 31.3; the refractive index N3 of the third lens G3 is 1.75, and the Abbe number V3 is 52.3; the refractive index N4 of the fourth lens G4 is 1.85, and the Abbe number V4 is 23.8; the refractive index N5 of the fifth lens G5 is 1.73, and the Abbe number V5 is 1. The refractive index N6 of the sixth lens element G6 is 1.95, and the Abbe number V6 is 17.9; the refractive index N7 of the seventh lens element G7 is 1.83, and the Abbe number V7 is 42.7; the refractive index N8 of the eighth lens element G8 is 1.88, and the Abbe number V8 is 39.2; the refractive index N9 of the ninth lens element G9 is 1.57, and the Abbe number V9 is 71.3; the refractive index N10 of the equivalent prism 10 is 1.71, and the Abbe number V10 is 53.8.

[0229] Example 3:

[0230] The projection lens of the embodiment of the present disclosure has an effective focal length f of 11 mm, an aperture number Fno of F / 1.7, a DMD size IMG of 12 mm, an operating wavelength range of 435 nm to 485 nm, a total optical length TTL of 85 mm, a back focus BFL of 21.4 mm, and an angle between the normal direction of the image source surface and the optical axis of 0°.

[0231] The focal length fa of first lens group L1 is -15.5mm, the focal length fb of second lens group L2 is 25.3mm, the focal length fc of third lens group L3 is -95mm, and the focal length fd of fourth lens group L4 is 14mm. The axial distance d12 between first lens group L1 and second lens group L2 is 7.3mm, the axial distance d23 between second lens group L2 and third lens group L3 is 11.9mm, and the axial distance d34 between third lens group L3 and fourth lens group L4 is 2.9mm.

[0232] The focal length fa of the first lens group L1 satisfies |fa / f|=1.4 with the effective focal length f of the projection lens, the focal length fb of the second lens group L2 satisfies fb / f=2.3 with the effective focal length f of the projection lens, the focal length fc of the third lens group L3 satisfies |fc / f|=8.7 with the effective focal length f of the projection lens, and the focal length fd of the fourth lens group L4 satisfies fd / f=1.3 with the effective focal length f of the projection lens.

[0233] The surface shapes of the lenses are as follows: the first lens G1 is a convex-concave lens, the second lens G2 is a convex-concave lens, the third lens G3 is a biconcave lens, the fourth lens G4 is a biconvex lens, the fifth lens G5 is a convex-concave lens, the sixth lens G6 is a biconcave lens, the seventh lens G7 is a biconvex lens, the sixth lens G6 and the seventh lens G7 are a cemented lens, the eighth lens G8 is a biconvex lens, and the ninth lens G9 is a convex-concave lens.

[0234] The curvature radii of each lens are as follows: the curvature radius R11 of the projection side surface of the first lens G1 is 32.1mm, and the curvature radius R12 of the image source side surface is 110.8mm; the curvature radius R21 of the projection side surface of the second lens G2 is 18.8mm, and the curvature radius R22 of the image source side surface is 10.2mm; the curvature radius R31 of the projection side surface of the third lens G3 is -68mm, and the curvature radius R32 of the image source side surface is 13.7mm; the curvature radius R41 of the projection side surface of the fourth lens G4 is 55.5mm, and the curvature radius R42 of the image source side surface is -36.6mm; the curvature radius R5 of the projection side surface of the fifth lens G5 is 10.2mm. The lens element G1 has a projection-side surface radius R1 of 43 mm, and a curvature radius R52 of the image-source-side surface of 26.2 mm. The sixth lens element G6 has a projection-side surface radius R61 of -76.2 mm, and a curvature radius R62 of the image-source-side surface of 33.7 mm. The seventh lens element G7 has a projection-side surface radius R71 of 33.7 mm, and a curvature radius R72 of the image-source-side surface of -29.4 mm. The eighth lens element G8 has a projection-side surface radius R81 of 48.7 mm, and a curvature radius R82 of the image-source-side surface of -48.7 mm. The ninth lens element G9 has a projection-side surface radius R91 of 24.4 mm, and a curvature radius R82 of the image-source-side surface of 221.5 mm.

[0235] The center thicknesses of the lenses are as follows: the center thickness GT1 of the first lens G1 is 5.1 mm; the center thickness GT2 of the second lens G2 is 4 mm; the center thickness GT3 of the third lens G3 is 1.5 mm; the center thickness GT4 of the fourth lens G4 is 2.5 mm; the center thickness GT5 of the fifth lens G5 is 5.2 mm; the center thickness GT6 of the sixth lens G6 is 1.5 mm; the center thickness GT7 of the seventh lens G7 is 5.1 mm; the center thickness GT8 of the eighth lens G8 is 4.8 mm; the center thickness GT9 of the ninth lens G9 is 5.2 mm; and the center thickness GT10 of the equivalent prism 10 is 13 mm.

[0236] The air spacing between the lenses is as follows: the air spacing distance AT1 between the first lens G1 and the second lens G2 along the optical axis is 0.5 mm; the air spacing distance AT2 between the second lens G2 and the third lens G3 along the optical axis is 4.5 mm; the air spacing distance AT3 between the third lens G3 and the fourth lens G4 along the optical axis is 7.3 mm; the air spacing distance AT4 between the fourth lens G4 and the aperture stop ST along the optical axis is 8.5 mm; the air spacing distance AT5 between the aperture stop ST and the fifth lens G5 along the optical axis is 3.4 mm; the air spacing distance AT6 between the fifth lens G5 and the fourth lens G4 along the optical axis is 1.6 mm; the air spacing distance AT7 between the fifth lens G5 and the fourth lens G4 along the optical axis is 2.8 mm; the air spacing distance AT8 between the fifth lens G5 and the fourth lens G4 along the optical axis is 3.9 mm. The air spacing distance AT6 along the optical axis of the sixth lens G6 is 2.9 mm; the sixth lens G6 and the seventh lens G7 are cemented lenses; the air spacing distance AT7 along the optical axis between the seventh lens G7 and the eighth lens G8 is 1.38 mm; the air spacing distance AT8 along the optical axis between the eighth lens G8 and the ninth lens G9 is 0.2 mm; the air spacing distance along the optical axis between the ninth lens G9 and the equivalent prism 10 is 6.2 mm, and the distance between the equivalent prism 10 and the image plane 12 along the optical axis is 2.2 mm. There is a cover glass 11 with a central thickness of 1.1 mm.

[0237] An air distance AT4 between the fourth lens G4 and the aperture stop ST along the optical axis and an air distance AT5 between the aperture stop ST and the fifth lens G5 along the optical axis satisfy AT4+AT5=11.9 mm.

[0238] The focal lengths of the lenses are as follows: the focal length f1 of the first lens G1 is 48 mm; the focal length f2 of the second lens G2 is -33 mm; the focal length f3 of the third lens G3 is -13 mm; the focal length f4 of the fourth lens G4 is 25 mm; the focal length f5 of the fifth lens G5 is -95 mm; the focal length f6 of the sixth lens G6 is -23 mm; the focal length f7 of the seventh lens G7 is 20.6 mm; the focal length f8 of the eighth lens G8 is 27.6 mm; and the focal length f9 of the ninth lens G9 is 43.1 mm.

[0239] The optical material parameters of each lens are as follows: the refractive index N1 of the first lens G1 is 1.88, and the Abbe number V1 is 39.2; the refractive index N2 of the second lens G2 is 1.83, and the Abbe number V2 is 42.7; the refractive index N3 of the third lens G3 is 1.85, and the Abbe number V3 is 32.3; the refractive index N4 of the fourth lens G4 is 1.85, and the Abbe number V4 is 23.8; the refractive index N5 of the fifth lens G5 is 1.78, and the Abbe number V5 is 1.78. The refractive index N6 of the sixth lens element G6 is 1.95, and the Abbe number V6 is 17.9; the refractive index N7 of the seventh lens element G7 is 1.77, and the Abbe number V7 is 49.6; the refractive index N8 of the eighth lens element G8 is 1.88, and the Abbe number V8 is 39.2; the refractive index N9 of the ninth lens element G9 is 1.62, and the Abbe number V9 is 60.3; the refractive index N10 of the equivalent prism 10 is 1.71, and the Abbe number V10 is 53.8.

[0240] The projection lens of the embodiment of the present disclosure can achieve high-quality imaging or light beam projection under the matching numerical aperture (NA) of the light source 21 to meet the needs of scenes such as defect detection and three-dimensional imaging.

[0241] Example 5

[0242] An embodiment of the present disclosure further provides an electronic device, comprising the optical engine of the above embodiment and a camera, wherein the optical engine is used to project a pattern toward the surface of the object to be measured, and the camera is used to capture light reflected from the surface of the object to be measured and form an image.

[0243] The structure, function and effect of the optical engine provided in this embodiment are the same as those in the above embodiment. For details, please refer to the above embodiment and will not be described again here.

[0244] Since the electronic device of this embodiment includes the optical engine of the above embodiment, the electronic device of the embodiment of the present disclosure also has the same advantages as the optical engine of the above embodiment.

[0245] In the above description, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without mutual contradiction.

[0246] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. An optical engine, characterized in that: include: A projection lens and an illumination module, wherein the projection lens is fixedly connected to the illumination module; the illumination module comprises a light source module, a light homogenization module, and a spatial light modulator; The light emitted by the light source module passes through the light homogenization module and is emitted to the spatial light modulator; the spatial light modulator generates a structured light pattern and projects it to the target object through the projection lens; The light source module emits light along a first direction, and the projection lens emits light along a second direction; the second direction is not opposite to the first direction.

2. The optical engine according to claim 1, wherein: The central axis of the projection lens extends along the second direction; the central axis of the light source module extends along the first direction; The central axis of the projection lens and the central axis of the light source module are skew lines.

3. The optical engine according to claim 1, wherein: The central axis of the projection lens and the central axis of the light source module are coplanar straight lines, and the plane defined by the central axis of the projection lens and the central axis of the light source module is a first plane; The projection lens and the light source module are spaced apart in a first plane.

4. The optical engine according to claim 3, wherein: The projection lens is located on a side of the light source module from which light is emitted; and along an extending direction of a central axis of the light source module, a gap is provided between the projection lens and the light source module.

5. The optical engine according to claim 4, wherein: An extension direction of a central axis of the projection lens is parallel to an extension direction of a central axis of the light source module, so that an angle between the second direction and the first direction is equal to 0°.

6. The optical engine according to claim 4, wherein: The light homogenization module and the spatial light modulator are located in a space between the projection lens and the light source module.

7. The optical engine according to claim 1, wherein: The light homogenizing module includes a prism, a housing portion, and a fixing member. The prism is located in the housing portion. The fixing member is fixedly connected to the housing portion and elastically contacts the prism.

8. The optical engine according to claim 7, wherein: The fixing member is a spring screw.

9. The optical engine according to claim 1, wherein: The image source plane of the spatial light modulator, the principal plane of the projection lens, and the projection plane of the target object are extended to intersect on the same straight line, satisfying Schaam's law; The included angle β between the image source plane and the optical axis is 80° to 90°.

10. The optical engine according to any one of claims 1 to 9, characterized in that: The light source module includes a light source and a first lens, a second lens, and a third lens arranged in sequence along the light emission direction of the optical axis; The light homogenization module includes a light homogenization element, a fourth lens, a reflector, a fifth lens, and a prism, which are sequentially arranged along the optical emission direction of the optical axis.

11. The optical engine according to claim 10, wherein: The first lens is a concave-convex lens, the second lens is a concave-convex lens, the third lens is a concave-convex lens, the fourth lens is a biconvex lens, and the fifth lens is a biconvex lens.

12. The optical engine according to claim 10, wherein: The curvature radius R011 of the incident surface of the first lens is -25mm to -15mm, and the curvature radius R012 of the exit surface is -10mm to -1mm; the curvature radius R021 of the incident surface of the second lens is -80mm to -70mm, and the curvature radius R022 of the exit surface is -15mm to -5mm; the curvature radius R031 of the incident surface of the third lens is -10mm to -1mm, and the curvature radius R032 of the exit surface is -10mm to -1mm; the curvature radius R051 of the incident surface of the fourth lens is 100mm to 110mm, and the curvature radius R052 of the exit surface is 100mm to 110mm; the curvature radius R071 of the incident surface of the fifth lens is -40mm to -30mm, and the curvature radius R072 of the exit surface is 30mm to 40mm.

13. The optical engine according to claim 10, wherein: The focal length f01 of the first lens is 5mm to 15mm; the focal length f02 of the second lens is 10mm to 20mm; the focal length f03 of the third lens is -80mm to -70mm; the focal length f05 of the fourth lens is 60mm to 70mm; and the focal length f07 of the fifth lens is -25mm to -15mm.

14. The optical engine according to claim 10, wherein: The focal length f01 of the first lens and the effective focal length f of the projection lens satisfy 0<|f01 / f|<1; the focal length f02 of the second lens and the effective focal length f of the projection lens satisfy 0.5<|f02 / f|<1.5; the focal length f03 of the third lens and the effective focal length f of the projection lens satisfy 2<|f03 / f|<4; the focal length f05 of the fourth lens and the effective focal length f of the projection lens satisfy 2<|f05 / f|<4; the focal length f07 of the fifth lens and the effective focal length f of the projection lens satisfy 0.5<|f07 / f|<1.

5.

15. The optical engine according to claim 10, wherein: The refractive index N01 of the first lens is 1.7 to 1.9, and the Abbe number V01 is 20 to 25; the refractive index N02 of the second lens is 1.7 to 1.9, and the Abbe number V02 is 45 to 50; the refractive index N03 of the third lens is 1.7 to 1.9, and the Abbe number V03 is 45 to 50; the refractive index N05 of the fourth lens is 1.7 to 1.9, and the Abbe number V04 is 45 to 50; the refractive index N07 of the fifth lens is 1.7 to 1.9, and the Abbe number V05 is 45 to 50.

16. The optical engine according to claim 10, wherein: The center thickness GT01 of the first lens is 3 mm to 6 mm; the center thickness GT02 of the second lens is 2 mm to 6 mm; The center thickness GT03 of the third lens is 1 mm to 4 mm; the center thickness GT05 of the fourth lens is 1 mm to 4 mm; and the center thickness GT07 of the fifth lens is 3 mm to 6 mm.

17. The optical engine according to claim 10, wherein: The air distance AT00 between the light source and the first lens along the optical axis is 0 mm to 2 mm; the air distance AT01 between the first lens and the second lens along the optical axis is 0 mm to 2 mm; the air distance AT02 between the second lens and the third lens along the optical axis is 0 mm to 2 mm; the air distance AT03 between the third lens and the light homogenizing element along the optical axis is 1 mm to 4 mm; the air distance AT04 between the light homogenizing element and the fourth lens along the optical axis is 1 mm to 3 mm; the air distance AT05 between the fourth lens and the center of the reflector along the optical axis is 8 mm to 11 mm; the air distance AT06 between the center of the reflector and the fifth lens along the optical axis is 9 mm to 12 mm; the air distance AT07 between the fifth lens and the prism along the optical axis is 3 mm to 7 mm; and the air distance AT08 between the prism and the image source plane of the spatial light modulator along the optical axis is 0 mm to 2 mm.

18. The optical engine according to any one of claims 1 to 9, characterized in that: The projection lens comprises: a first lens group, a second lens group, a third lens group, and a fourth lens group, arranged in sequence along the optical axis from one side of the projection surface to one side of the image source surface of the spatial light modulator, with an aperture stop provided between the second lens group and the third lens group; wherein the projection surface is used to receive a projection image; The optical power of the first lens group is negative, the optical power of the second lens group is positive, the optical power of the third lens group is negative, and the optical power of the fourth lens group is positive; The image source plane is arranged perpendicularly or obliquely relative to the optical axis, and an angle θ between a normal direction of the image source plane and the optical axis is 0° to 10°.

19. The optical engine according to claim 18, wherein: The focal length fa of the first lens group satisfies |fa / f|=1.4-1.9 with the effective focal length f of the projection lens, the focal length fb of the second lens group satisfies fb / f=1.2-2.4 with the effective focal length f of the projection lens, the focal length fc of the third lens group satisfies |fc / f|=3.2-8.7 with the effective focal length f of the projection lens, and the focal length fd of the fourth lens group satisfies fd / f=0.7-1.3 with the effective focal length f of the projection lens.

20. The optical engine according to claim 18, wherein: The focal length fa of the first lens group is -26.5mm to -12.4mm, the focal length fb of the second lens group is 16.5mm to 25.3mm, the focal length fc of the third lens group is -95mm to -45mm, and the focal length fd of the fourth lens group is 10mm to 14mm.

21. The optical engine according to claim 18, wherein: An axial distance d12 between the first lens group and the second lens group is 0.2 mm to 7.3 mm, an axial distance d23 between the second lens group and the third lens group is 2.9 mm to 11.9 mm, and an axial distance d34 between the third lens group and the fourth lens group is 1.8 mm to 2.9 mm.

22. The optical engine according to claim 18, wherein: The projection lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens along the optical axis from the projection surface to the image source surface, wherein the first lens, the second lens, and the third lens form a first lens group; the fourth lens forms the second lens group, the fifth lens forms the third lens group, and the sixth lens, the seventh lens, and the eighth lens form the fourth lens group.

23. The optical engine according to claim 22, wherein: The first lens is a convex-plano lens with positive power, the second lens is a convex-concave lens with negative power, the third lens is a concave-convex lens with negative power, the fourth lens is a concave-convex lens with positive power, the fifth lens is a convex-concave lens with negative power, the sixth lens is a biconcave lens with negative power, the seventh lens is a biconvex lens with positive power, the sixth lens and the seventh lens are a cemented lens, and the eighth lens is a biconvex lens with positive power.

24. The optical engine according to claim 18, wherein: The projection lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens along the optical axis from the projection surface to the image source surface, wherein the first lens forms the first lens group; the second lens, the third lens, and the fourth lens form the second lens group; the fifth lens forms the third lens group; and the sixth lens, the seventh lens, the eighth lens, and the ninth lens form the fourth lens group.

25. The optical engine according to claim 24, wherein: The first lens is a convex-plano lens or a convex-concave lens with positive power, the second lens is a convex-concave lens with negative power, the third lens is a concave-convex lens or a plano-concave lens or a biconcave lens with negative power, the fourth lens is a concave-convex lens or a biconvex lens with positive power, the fifth lens is a convex-concave lens with negative power, the sixth lens is a biconcave lens with negative power, the seventh lens is a biconvex lens with positive power, the eighth lens is a biconvex lens with positive power, and the ninth lens is a convex-plano lens or a convex-concave lens with positive power.

26. The optical engine according to any one of claims 22 to 25, wherein: The curvature radius R11 of the projection side surface of the first lens is 18.6mm~32.1mm, and the curvature radius R12 of the image source side surface is greater than or equal to 110.8mm; the curvature radius R21 of the projection side surface of the second lens is 10.1mm~18.8mm, and the curvature radius R22 of the image source side surface is 4.2mm~10.2mm; the curvature radius R31 of the projection side surface of the third lens is -68mm~-6.8mm, and the curvature radius R32 of the image source side surface is -16.2mm~13.7mm; the curvature radius R41 of the projection side surface of the fourth lens is -34mm~55.5mm, and the curvature radius R42 of the image source side surface is -39.6mm~-10.3mm; The curvature radius R51 of the projection-side surface of the fifth lens is 16.36 mm to 43 mm, and the curvature radius R52 of the image-source-side surface is 10.4 mm to 26.2 mm; the curvature radius R61 of the projection-side surface of the sixth lens is -76.2 mm to -18.2 mm, and the curvature radius R62 of the image-source-side surface is 30.7 mm to 39 mm; the curvature radius R71 of the projection-side surface of the seventh lens is 30.7 mm to 39 mm, and the curvature radius R72 of the image-source-side surface is -29.4 mm to -9.8 mm; the curvature radius R81 of the projection-side surface of the eighth lens is 19.82 mm to 48.7 mm, and the curvature radius R82 of the image-source-side surface is -50.3 mm to -25.74 mm; Wherein, the projection side surface faces the projection surface, and the image source side surface faces the image source surface.

27. The optical engine according to any one of claims 22 to 25, wherein: The center thickness GT1 of the first lens is 3 mm to 5.1 mm; the center thickness GT2 of the second lens is 3 mm to 4 mm; the center thickness GT3 of the third lens is 1.5 mm to 3 mm; the center thickness GT4 of the fourth lens is 1.6 mm to 2.5 mm; the center thickness GT5 of the fifth lens is 3 mm to 5.2 mm; the center thickness GT6 of the sixth lens is 1.5 mm to 2.3 mm; the center thickness GT7 of the seventh lens is 3 mm to 5.1 mm; and the center thickness GT8 of the eighth lens is 3 mm to 4.8 mm.

28. The optical engine according to any one of claims 22 to 25, wherein: An air distance AT1 between the first lens and the second lens along the optical axis is 0.2 mm to 2.2 mm; an air distance AT2 between the second lens and the third lens along the optical axis is 2.2 mm to 4.5 mm; an air distance AT3 between the third lens and the fourth lens along the optical axis is 0.2 mm to 7.3 mm; an air distance AT4 between the fourth lens and the aperture stop along the optical axis is 0.6 mm to 8.5 mm; an air distance AT5 between the aperture stop and the fifth lens along the optical axis is 1.2 mm to 3.4 mm; an air distance AT6 between the fifth lens and the sixth lens along the optical axis is 1.8 mm to 2.9 mm; the sixth lens and the seventh lens are cemented lenses; and an air distance AT7 between the seventh lens and the eighth lens along the optical axis is 0.2 mm to 1.38 mm.

29. The optical engine according to any one of claims 22 to 25, wherein: The focal length f1 of the first lens is 25mm to 48mm; the focal length f2 of the second lens is -33mm to -13mm; the focal length f3 of the third lens is -19mm to -13mm; the focal length f4 of the fourth lens is 17mm to 25mm; the focal length f5 of the fifth lens is -95mm to -46mm; the focal length f6 of the sixth lens is -23mm to -15mm; the focal length f7 of the seventh lens is 13mm to 20.6mm; and the focal length f8 of the eighth lens is 15mm to 27.6mm.

30. The optical engine according to any one of claims 22 to 25, wherein: The refractive index N1 of the first lens is 1.73-1.88, and the Abbe number V1 is 39.2-54.7; the refractive index N2 of the second lens is 1.52-1.9, and the Abbe number V2 is 31.3-58.6; the refractive index N3 of the third lens is 1.7-1.85, and the Abbe number V3 is 30-52.3; the refractive index N4 of the fourth lens is 1.83-1.85, and the Abbe number V4 is 23.8-42.7; The refractive index N5 of the fifth lens is 1.73-1.78, and the Abbe number V5 is 25.7-28.3; the refractive index N6 of the sixth lens is 1.76-1.95, and the Abbe number V6 is 17.9-26.6; the refractive index N7 of the seventh lens is 1.62-1.83, and the Abbe number V7 is 42.7-63.4; the refractive index N8 of the eighth lens is 1.75-1.88, and the Abbe number V8 is 39.2-52.

3.

31. The optical engine according to claim 24 or 25, wherein: The curvature radius R91 of the projection side surface of the ninth lens is 19.7 mm to 24.4 mm, and the curvature radius R92 of the image source side surface is greater than or equal to 221.5 mm; The center thickness GT9 of the ninth lens is 4 mm to 5.2 mm; The air spacing distance AT8 between the eighth lens and the ninth lens along the optical axis is 0.2 mm; The focal length f9 of the ninth lens is 34 mm to 43.1 mm; The refractive index N8 of the ninth lens is 1.57-1.62, and the Abbe number V8 is 60.3-71.

3.

32. The optical engine according to claim 18, wherein: The effective focal length f of the projection lens is 8 mm to 14 mm, the aperture number Fno is F / 1.7 to F / 4.2, the size IMG of the image source surface of the spatial light modulator is 8 mm to 12 mm, the operating band is 390 nm to 700 nm, the total optical length TTL of the projection lens is 50 mm to 85 mm, and the system back focus BFL is 17.5 mm to 21.4 mm.

33. The optical engine according to claim 18, wherein: The distortion curve of the projection lens changes monotonically over the entire field of view; The MTF contrast ratio of each field of view of the projection lens at a spatial frequency of 93 cycles / mm is greater than 0.7; The relative illumination of the entire viewing field of the projection lens is greater than 96%.

34. The optical engine according to claim 1, wherein: All lenses are made of glass and all lenses are spherical lenses.

35. An electronic device comprising a camera and the optical engine according to any one of claims 1 to 34, wherein the optical engine is used to project a pattern toward a surface of an object to be measured, and the camera is used to capture light reflected from the surface of the object to be measured and form an image.

Images