Internal reflection light projector

Abstract

The application provides an inner reflection type light projector, comprising a light source module and a telecentric lens arranged in sequence along a light path; the telecentric lens comprises a first lens assembly, a reflecting device and a second lens assembly; the light source module is used for emitting a plurality of discrete collimated light beams; the first lens assembly comprises a first lens; the first lens assembly is used for receiving the discrete collimated light beams, converging the discrete collimated light beams so that the discrete collimated light beams are converged at a diaphragm position of the second lens assembly after being folded by the reflecting device; the second lens assembly is used for receiving the discrete collimated light beams reflected by the reflecting device and changing a focusing plane by moving along an optical axis direction to realize switching between a point light array and a surface light array of the projected discrete collimated light beams. The application can realize projection of two lights by a single light source, effectively reduce the cost of a 3D camera and facilitate miniaturization of the 3D camera.

Description

TECHNICAL FIELD

[0001] The present application relates to 3D depth vision, in particular, to an internal reflection light projector. BACKGROUND

[0002] As a brand-new technology, 3D depth vision has appeared in consumer-level products such as mobile phones, motion games, and payments, and gradually penetrated into new fields such as security and automatic driving. With the continuous progress of hardware technology and the continuous optimization of algorithms and software, the accuracy and practicality of 3D depth vision have been greatly improved.

[0003] The main schemes currently used for 3D depth perception are binocular stereo vision, 3D structured light, and TOF scheme. Among them, binocular stereo vision generally uses two cameras to obtain two digital images of the measured object from different angles at the same time, and restores the three-dimensional geometric information of the object based on the principle of parallax, reconstructs the three-dimensional profile and position of the object. The principle of 3D structured light is to emit a diffraction spot to the object, and the sensor receives the deformed spot, so as to judge the depth information according to the amount of spot deformation. 3D structured light has high precision and is suitable for close-range information collection, such as face recognition, face payment, and other functions. The TOF scheme is to continuously send light signals to the measured target, and then the sensor receives the returned light signals, and then calculates the flight time of a series of light signals to obtain the distance of the measured target.

[0004] Among them, 3D structured light and TOF scheme both need a transmitting end and a receiving end. The general transmitting end includes a laser light source, a collimating light path, and a DOE, or a laser light source, a collimating light path, a chip, and a projection lens. No matter which scheme is adopted, the light needs to propagate through a long distance from the light source to the exit position, so it will cause the product to have a large thickness, which is not conducive to the miniaturization of the entire product.

[0005] The projection lens usually adopts an object-side telecentric light path to achieve uniform field of view and CRA matching. Due to the principle limitation of the telecentric projection lens, there will be a large gap between the first lens and the subsequent lens group. The conventional design scheme is a direct-down structure, as shown in FIG. 1, the object plane is perpendicular to the optical axis, and the light rays pass through the object plane and the telecentric lens from bottom to top to project the object plane image. Or add a reflecting mirror at the end of the lens to realize 90° folding of the light beam to reduce the system height, but this further increases the length of the lens, as shown in FIG. 2. Figure 2 Figure 3

[0006] With the development of portable terminal devices such as mobile phones and tablet computers, in certain applications, it is required that the device has a projection function. The conventional telecentric projection lens design needs to occupy a large space volume, which limits its application in portable devices.

[0007] ​​In addition, the emitting end in the prior art 3D structured light and TOF scheme can only project structured light or flood light, and a flood light source and a structured light source need to be assembled, which not only increases the cost and power consumption of the entire 3D camera, but also is not conducive to the miniaturization of the 3D camera.

[0008] Therefore, how to reduce the cost of the 3D camera and realize miniaturization is a technical problem to be solved by those skilled in the art. SUMMARY

[0009] In view of the defects in the prior art, the purpose of the present application is to provide an internal reflection light projector, which changes the focusing plane by moving the second lens assembly along the optical axis direction, so as to realize the switching of the discrete collimated light beams projected by the light source module between the point light array and the surface light array.

[0010] The internal reflection light projector provided by the present application comprises a light source module and a telecentric lens arranged in sequence along an optical path; the telecentric lens comprises a first lens assembly, a reflecting device and a second lens assembly;

[0011] The light source module is used for emitting a plurality of discrete collimated light beams;

[0012] The first lens assembly comprises a first lens; the image side of the first lens is arranged with the reflecting device;

[0013] The first lens assembly is used for receiving the discrete collimated light beams and converging the discrete collimated light beams, so that the discrete collimated light beams are converged at the diaphragm position of the second lens assembly after being folded by the reflecting device;

[0014] The second lens assembly is used for receiving the discrete collimated light beams reflected by the reflecting device, and changing the focusing plane by moving along the optical axis direction, so as to realize the switching of the discrete collimated light beams between the point light array and the surface light array.

[0015] Preferably, the second lens assembly comprises a second lens, a third lens and a fourth lens arranged in sequence along the optical path;

[0016] The image side of the first lens is arranged with the reflecting device, the image side of the reflecting device is arranged with the second lens, the image side of the second lens is arranged with the third lens, and the image side of the third lens is arranged with the fourth lens.

[0017] Preferably, the first lens has a positive focal power, and the object side and the image side are convex structures;

[0018] The second lens has a positive focal power, the object side is convex, and the image side is concave;

[0019] The third lens has positive refractive power, a concave object side surface, and a convex image side surface.

[0020] The fourth lens has negative refractive power, a concave object side surface, and a convex image side surface.

[0021] Preferably, the chief rays at different image heights of the object plane of the telecentric lens are parallel to the optical axis of the first lens.

[0022] Preferably, the reflecting surface of the reflecting device is a metal layer, a dielectric film coating, or an internal total reflection surface of a prism.

[0023] Preferably, the reflecting surface of the reflecting device is a plane, which is arranged between the optical paths of the first lens and the second lens, and is inclined by 40° to 50° with respect to the optical axes of the first lens, the second lens, the third lens, and the fourth lens.

[0024] The reflecting device is used to fold the discrete collimated light beams emitted by the first lens by 90° and project them to the second lens.

[0025] Preferably, the optical distance between the first lens and the second lens and the size of the reflecting device satisfy the following conditional expression:

[0026]

[0027] Preferably, a diaphragm is arranged between the second lens and the third lens, so that the telecentric lens satisfies the following conditional expression:

[0028] 73° < FOV < 112°

[0029] wherein FOV is the field of view of the telecentric lens.

[0030] 0.95 < VP < 1

[0031] wherein VP is the depth of view of the telecentric lens.

[0032] | Distortion | < 8%

[0033] wherein Distortion is the optical distortion of the optical system.

[0034] Preferably, the first lens, the second lens, the third lens, and the fourth lens are made of aspherical plastic lenses.

[0035] The refractive index nd of the first lens, the second lens, the third lens, and the fourth lens satisfies the following formula:

[0036] 1.62 < nd < 1.69

[0037] Wherein, nd is the refractive index of the lens at 587.6nm wavelength.

[0038] Preferably, the second lens assembly is capable of moving along the optical axis direction, changing the optical distance between the first lens assembly and the second lens assembly to change the object side focal length of the telecentric lens, and realizing the focusing on different image plane positions.

[0039] When the distance between the light source module and the first lens assembly decreases, the second lens assembly is moved towards the reflecting device.

[0040] When the distance between the light source module and the first lens assembly increases, the second lens assembly is moved away from the reflecting device.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] In the present application, the telecentric lens focusing plane is adjusted by moving the second lens assembly, so that the dispersed collimated light beam of the light source module is defocused, that is, the size of each point in the dot matrix light array is increased, and when the point density is high enough, all the points will be connected after the defocusing of the axial focal point, and then become floodlight output, so that the switching between dot matrix light and floodlight output can be realized, thereby realizing the projection of two lights by a single light source, effectively reducing the cost of 3D camera, and facilitating the miniaturization of 3D camera.

[0043] In the present application, the reflecting device is arranged between the first lens assembly and the second lens assembly, which shortens the optical path length of the entire telecentric lens, and thus reduces the height of the telecentric lens, so that the telecentric lens can be applied to electronic devices such as mobile phones which have requirements for thickness.

[0044] In the present application, when the relative position of the light source module and the first lens assembly changes, the second lens assembly can be moved correspondingly to realize grouped focusing, so as to facilitate the focusing of the light projector using the telecentric lens, thereby matching different light source module positions without adjusting the positional relationship between the light source module and the first lens. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and those skilled in the art can obtain other drawings without creative labor based on the provided drawings. Other features, objects and advantages of the present application will become more apparent through reading the following detailed description of the non-limiting embodiments with reference to the accompanying drawings:

[0046] Figure 1(a) is a schematic diagram of a structure of an internal reflection light projector in an embodiment of the present application;

[0047] Figure 1(b) is a schematic diagram of another structure of an internal reflection light projector in an embodiment of the present application;

[0048] Figure 2 Figure 2 is a schematic diagram of a telecentric lens structure in which a reflecting device is omitted in an embodiment of the present application;

[0049] Figure 3 Figure 3 is a schematic diagram of a telecentric lens structure in which a reflecting device is located at an exit end in an embodiment of the present application;

[0050] Figure 4 Figure 4(a) is a schematic diagram of a side surface position in which an internal reflection light projector in an embodiment of the present application is assembled in a mobile phone;

[0051] Figure 4 Figure 4(b) is another schematic diagram of a side surface position in which an internal reflection light projector in an embodiment of the present application is assembled in a mobile phone;

[0052] Figure 5(a) is a schematic diagram of a size in which an internal reflection light projector in an embodiment of the present application is assembled in a mobile phone;

[0053] Figure 5(b) is a schematic diagram of a size in which a light projector in which a reflecting device is omitted in an embodiment of the present application is assembled in a mobile phone;

[0054] Figure 5(c) is a schematic diagram of a size in which a light projector in which a reflecting device is located at an exit end in an embodiment of the present application is assembled in a mobile phone;

[0055] Figure 6 Figure 6 is a schematic diagram of a focusing principle of a first lens assembly and a second lens assembly in an embodiment of the present application;

[0056] Figure 7 Figure 7 is a curve diagram of an MTF transfer function of an optical system in an embodiment of the present application;

[0057] Figure 8 Figure 8 is a curve diagram of a relative luminance of an optical system in an embodiment of the present application;

[0058] Figure 9 Figure 9 is a curve diagram of distortion of an optical system in an embodiment of the present application.

[0059] In the figures:

[0060] 1 is a light source module; 2 is a first lens; 3 is a reflecting device; 4 is a second lens; 5 is a diaphragm; 6 is a third lens; 7 is a fourth lens; 8 is a lens opening; 9 is a lens assembly; 10 is a first lens assembly; 11 is a second lens assembly. DETAILED DESCRIPTION

[0061] The application will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the application. These are within the scope of the application.

[0062] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, the connection can be for fixing or for circuit communication.

[0063] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0064] In addition, the terms "first", "second", "third", etc. are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the embodiments of the application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0065] In the embodiments of the application, the internal reflection type light projector provided by the application comprises a light source module and a telecentric lens arranged in sequence along an optical path; the telecentric lens comprises a first lens assembly, a reflecting device, and a second lens assembly;

[0066] The light source module is configured to emit a plurality of discrete collimated light beams;

[0067] The first lens assembly comprises a first lens; the image side of the first lens is arranged with the reflecting device;

[0068] The first lens assembly is configured to receive the discrete collimated light beams, and converge the discrete collimated light beams so that the discrete collimated light beams are converged at the stop position of the second lens assembly after being folded by the reflecting device;

[0069] The second lens assembly is used for receiving the discrete collimated light beams reflected by the reflecting device, and changing the focusing plane by moving along the optical axis direction to realize the switching between the point light array and the surface light array of the projected discrete collimated light beams.

[0070] In the application, the discrete collimated light beams of the light source module are defocused by moving the second lens assembly to adjust the focusing plane of the telecentric lens, that is, the size of each point in the point light array is increased, and when the point density is high enough, all the points are connected into a piece after the axial defocusing, and then become the floodlight output, so that the switching between the point array light and the floodlight output can be realized, the projection of the two lights can be realized by a single light source, the cost of the 3D camera can be effectively reduced, and the miniaturization of the 3D camera can be facilitated.

[0071] The above is the core idea of the application. In order to make the above-mentioned purposes, characteristics and advantages of the application more obvious and easy to understand, the technical solutions in the embodiments of the application will be described clearly and completely in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0072] Fig. 1(a) is a structural schematic diagram of an internal reflection type light projector in an embodiment of the application, and Fig. 1(b) is another structural schematic diagram of the internal reflection type light projector in the embodiment of the application. As shown in Fig. 1(a) and Fig. 1(b), the internal reflection type light projector provided by the application comprises a light source module and a telecentric lens which are sequentially arranged along the light path; the telecentric lens comprises a first lens assembly 10, a reflecting device 3 and a second lens assembly 11;

[0073] The light source module is used for emitting a plurality of discrete collimated light beams;

[0074] The first lens assembly 10 comprises a first lens 2; the second lens assembly 11 comprises a second lens, a third lens 6 and a fourth lens 7 which are sequentially arranged along the light path;

[0075] The image side of the first lens 2 is arranged with the reflecting device 3, the image side of the reflecting device 3 is arranged with the second lens 4, the image side of the second lens 4 is arranged with the third lens 6, and the image side of the third lens 6 is arranged with the fourth lens 7;

[0076] The first lens assembly 10 is used for receiving discrete collimated light beams, converging the discrete collimated light beams, and converging the discrete collimated light beams at the position of the diaphragm 5 of the second lens assembly 11 after being folded by the reflecting device 3; and the second lens assembly 11 is used for receiving the discrete collimated light beams reflected by the reflecting device 3 and projecting an image.

[0077] The light path composition of the internal reflection light projector comprises a light source module 1, a first lens 2, a reflecting mirror device 3, a second lens 4, a diaphragm 5, a third lens 6, and a fourth lens 7.

[0078] The light source module 1 is used for emitting a plurality of discrete collimated light beams.

[0079] In the embodiment of the present application, the first lens 2 is used for converging the discrete collimated light beams from the light source module 1, and the focal plane is at the diaphragm 5.

[0080] The reflecting mirror device 3 is used for reflecting and folding the discrete collimated light beams by 90°, and can adopt a plane film-coated mirror, and can improve the reflectivity of the light on the surface of the mirror through a metal layer or a multi-layer dielectric film coating, or can adopt a right-angle total reflection prism. Since the discrete collimated light beams are totally reflected on the inclined surface of the right-angle reflection prism, the light is incident on the inclined surface of the right-angle prism at an angle exceeding the critical angle of total reflection, so that 100% reflectivity can be achieved on the inclined surface without coating, but the right-angle surface needs to be coated with an anti-reflection film to improve the transmittance.

[0081] The second lens 4 adopts a meniscus convex lens, and is used for converging the discrete collimated light beams to the diaphragm 5.

[0082] The diaphragm 5 is a virtual plane, and the discrete collimated light beams are collected to the narrowest at the diaphragm 5.

[0083] The third lens 6 adopts a meniscus convex lens, and is used for diverging and projecting the discrete collimated light beams incident through the diaphragm 5.

[0084] The fourth lens 7 adopts a meniscus concave lens, and is used for further diverging and projecting the discrete collimated light beams incident through the third lens 6.

[0085] In the embodiment of the present application, the first lens 2 has positive focal power, and the object side and the image side are convex structures, and the chief rays of different image heights of the object plane of the telecentric lens are all parallel to the optical axis of the first lens 2.

[0086] The reflecting surface of the reflecting device 3 is a plane, which is inclined by 40-50 degrees relative to the optical axis of the first lens 2 or the second lens 4, the third lens 6 and the fourth lens 7, and preferably by 45 degrees; the reflecting device 3 is used to project the discrete collimated light beams emitted by the first lens 2 to the second lens 4 after being turned by 90 degrees.

[0087] The reflecting device 3 is arranged by taking the characteristics of the large optical distance between the first lens 2 and the second lens 4 and the small inclination angle of the optical path, and is embedded in the optical path to realize the folding of the optical path without increasing the total length of the telecentric lens, which is beneficial to the miniaturization of the lens.

[0088] The second lens 4 has positive focal power, and the object side is convex and the image side is concave.

[0089] The third lens 6 has positive focal power, and the object side is concave and the image side is convex.

[0090] The fourth lens 7 has negative focal power, and the object side is concave and the image side is convex.

[0091] In the embodiment of the present application, the optical distance between the first lens 2 and the second lens 4 and the size of the reflecting device 3 satisfy the following conditional formula:

[0092]

[0093] In the embodiment of the present application, the second lens 4 and the third lens 6 are provided with a diaphragm 5, so that the telecentric lens satisfies the following conditional formula:

[0094] 73°<FOV<112°

[0095] Wherein, FOV is the field of view of the telecentric lens; FOV is used to limit the range of the field of view of the lens to realize large-angle projection.

[0096] 0.95<VP<1

[0097] Wherein, VP is the depth of view of the telecentric lens; VP is used to constrain the depth of view of the lens, reduce the size of the aperture, and reduce the vignetting, which is beneficial to improving the uniformity of the illumination of the image surface.

[0098] |Distortion|<8%

[0099] Wherein, Distortion is the optical distortion of the optical system; Distortion is used to constrain the distortion of the wide-angle lens, and the smaller the distortion is, the more real the image contour is.

[0100] In an embodiment of the present application, the chief rays at different image heights of the object plane of the telecentric lens are parallel to the optical axis of the first lens 2.

[0101] In an embodiment of the present application, the light source module 1 comprises an edge-emitting laser and a beam projector arranged on an optical path.

[0102] The edge-emitting laser is configured to project laser light to the beam projector.

[0103] The beam projector is configured to project the incident laser light into a plurality of discrete collimated light beams.

[0104] The inner surface of the beam splitter is processed with a micro-nano structure light chip and cooperates with an optical lens. The beam splitter can split the incident light from the edge-emitting laser into a plurality of collimated light beams. The emission direction of the edge-emitting laser 201 and the projection direction of the beam splitter can be the same, or can be 90 degrees or any angle required by the optical system design. The beam splitter can be a diffraction chip.

[0105] In an embodiment of the present application, the light source module 1 comprises a laser array, a collimating lens, and a beam splitting device arranged on an optical path.

[0106] The laser array is configured to project a first order of magnitude of laser light to the collimating lens.

[0107] The collimating lens is configured to collimate the incident plurality of laser beams and emit a first order of magnitude of collimated light beams.

[0108] The beam splitting device is configured to split the incident first order of magnitude of collimated light beams and emit a second order of magnitude of collimated light beams.

[0109] The second order of magnitude is greater than the first order of magnitude.

[0110] In an embodiment of the present application, the second order of magnitude is one to two times the first order of magnitude.

[0111] In an embodiment of the present application, the laser array can comprise a plurality of vertical cavity surface emitting lasers (VCSELs) or a plurality of edge-emitting lasers (EELs). After passing through the collimating lens, the plurality of laser beams can become highly parallel collimated light beams. According to the actual application, the beam splitting device can be used to achieve more collimated light beams according to the number of discrete light beams required. The beam splitting device can be a diffraction grating (DOE), a spatial light modulator (SLM), etc.

[0112] In one embodiment of the present invention, the first lens 2, the second lens 4, the third lens 6, and the fourth lens 7 are aspherical plastic lenses. The refractive indices nd of the first lens 2, the second lens 4, the third lens 6, and the fourth lens 7 satisfy the following formula:

[0113] 1.62 <nd<1.69

[0114] Where nd is the refractive index of the lens at a wavelength of 587.6 nm.

[0115] The center of the light source module 1 is on the same straight line as the optical axis of the first lens 2;

[0116] The optical axes of the second lens 4, the third lens 6, and the fourth lens 7 are on the same straight line;

[0117] The optical axis of the first lens 2 is perpendicular to the optical axes of the second lens 4, the third lens 6, and the fourth lens 7.

[0118] In one embodiment of the present invention, when the light source module 1 projects a multi-layer pattern, the focus plane can be changed by adjusting the second lens assembly to achieve image switching projection at different depths.

[0119] Figure 2 This is a schematic diagram of a light projector structure with the reflective device omitted in an embodiment of the present invention, as shown below. Figure 2 As shown, the optical axes of the light source module 1, the first lens 2, the second lens 4, the third lens 6, and the fourth lens 7 are all on the same straight line, which can achieve the same projection effect. However, the height of the telecentric lens is significantly increased after omitting the reflector 3.

[0120] Figure 3 This is a schematic diagram of the light projector structure with the reflective device 3 located at the light-emitting end in an embodiment of the present invention, as shown below. Figure 3 As shown, the optical axes of the light source module 1, the first lens 2, the second lens 4, the third lens 6, and the fourth lens 7 are all on the same straight line. A reflective device 3 is set on the image side of the fourth lens 7, which can achieve the same projection effect, but the length and height of the telecentric lens are significantly increased.

[0121] Figure 4 (a) is a schematic diagram showing the position of one side of the internal reflection light projector assembled in a mobile phone according to an embodiment of the present invention. Figure 4 (b) is a schematic diagram showing the position of the internal reflection light projector assembled in a mobile phone according to an embodiment of the present invention, as shown below. Figure 4 (a) and Figure 4 In (b), there are restrictions on the height and aperture size of the telecentric lens in compact devices such as mobile phones. Therefore, the smaller the aperture size of the telecentric lens, the better, and the height of the telecentric lens needs to be less than the thickness of the mobile phone.

[0122] Figure 5(a) is a size schematic diagram of the internal reflection light projector in the embodiment of the present application assembled in a mobile phone, Figure 5(b) is a size schematic diagram of the telecentric lens without the reflecting device in the embodiment of the present application assembled in a mobile phone, Figure 5(c) is a size schematic diagram of the telecentric lens with the reflecting device located at the light emitting end in the embodiment of the present application assembled in a mobile phone, as shown in Figure 5(a), Figure 5(b), Figure 5(c), the internal reflection light projector in the embodiment of the present application has a lower optical height relative to the telecentric lens without the reflecting device 3, the internal reflection light projector has a lower optical height, shorter length and smaller aperture relative to the telecentric lens with the reflecting device 3 located at the light emitting end, which can have better compatibility in compact devices.

[0123] Figure 6 Figure 6 is a schematic diagram of the focusing principle of the first lens assembly and the second lens assembly in the embodiment of the present application, as shown in Figure 6, the second lens assembly 11 can move along the optical axis direction, so as to adjust the focal length; Figure 6

[0124] For example, when the light source module 1 is located at the dotted line, the relative displacement between the first lens assembly 10 and the light source module 1 loses focus, that is, a horizontal displacement as shown in Figure 7 occurs, then the position of the second lens assembly 11 can be adjusted by the vertical movement as shown in Figure 8 to compensate, and refocus. Figure 6 Figure 6

[0125] Specifically, when the distance between the light source module 1 and the first lens assembly 10 decreases, the second lens assembly 11 is moved towards the reflecting device 3; when the distance between the light source module 1 and the first lens assembly 10 increases, the second lens assembly 11 is moved away from the reflecting device 3.

[0126] In the embodiment of the present application, the surface type, curvature radius, thickness and material refractive index nd and dispersion coefficient vd of the light source module 1, the first lens 2, the reflecting mirror device 3, the second lens 4, the diaphragm 5, the third lens 6 and the fourth lens 7 are shown in Table 1.

[0127] Table 1

[0128] Surface No. Surface Class Radius of Curvature Thickness Material (hd, vd) 1 Asphere 3.233 0.353 1.65，25.48 2 Asphere 0.664 0.575 3 Asphere 0.866 0.329 1.64，27.56 4 Asphere 0.780 0.145 Stop Plane Infinite 0.110 6 Asphere -3.923 0.644 1.66，20.37 7 Asphere -0.711 1.415 Mirror Plane Infinite 0.802 9 Sphere 2.975 0.462 1.62，33.24 10 Sphere -3.405 0.391 Object Plane Plane Infinite 0.000

[0129] ​​​In Table 1, surface number 1 is the light-emitting surface of the fourth lens 7, surface number 2 is the light-receiving surface of the fourth lens 7; surface number 3 is the light-emitting surface of the third lens 6, surface number 4 is the light-receiving surface of the third lens 6; surface number 6 is the light-emitting surface of the second lens 4, surface number 7 is the light-receiving surface of the second lens 4; surface number 9 is the light-emitting surface of the first lens 2, and surface number 10 is the light-receiving surface of the first lens 2.

[0130] Figure 7 This is a graph of the MTF transfer function of the optical system in this embodiment of the invention. The MTF transfer function can comprehensively reflect the imaging quality of the optical system. The higher and smoother the curve is on the Y-axis, the better the imaging quality of the optical system. Figure 7 As shown, the horizontal axis, SPATIAL FREQUENCY IN CYCLES PER MILLIMETER, represents the spatial frequency of line pairs / 1p / mm. The vertical axis represents the MTF value. The higher the curve, the better the image quality. The vertical axis, MODULUS OF THEOTF, where OTF stands for optical transfer function, represents the optical modulation transfer function. In this embodiment, the internal reflection light projector has a resolution >110 lp / mm.

[0131] Figure 8 This is a relative illumination curve of the optical system in an embodiment of the present invention, such as... Figure 8 As shown, the vertical axis Relative Illumination represents relative illumination, and the horizontal axis Y Field Millimeters represents the height in the Y direction, with units in millimeters.

[0132] Among them, the higher the height of the curve on the Y-axis and the smoother it is, the more uniform the relative illumination of the optical system is. In this embodiment of the invention, the maximum field of view relative illumination of the internal reflection light projector is >70%.

[0133] Figure 9 This is a distortion curve diagram of the optical system in an embodiment of the present invention, such as... Figure 9 As shown, the horizontal axis represents Percent, and the vertical axis represents Distortion. In this embodiment of the invention, the distortion of the internal reflection light projector is <7% across the entire field of view.

[0134] The embodiment of the present application adjusts the focusing plane of the telecentric lens by moving the second lens assembly, so that the discrete collimated light beams of the light source module are defocused, that is, the size of each point in the point array is increased, and when the point density is high enough, all the points will be connected after the defocusing of the axial focus, and then become a floodlight output, so that the switching between the point array light and the floodlight output can be realized, thereby realizing the projection of two lights by a single light source, effectively reducing the cost of the 3D camera, and facilitating the miniaturization of the 3D camera; in the embodiment of the present application, the reflector is arranged between the first lens assembly and the second lens assembly, so as to shorten the optical path length of the entire telecentric lens, thereby reducing the height of the telecentric lens, so that the telecentric lens can be applied to electronic devices such as mobile phones which have requirements on thickness; in the embodiment of the present application, when the relative position of the light source module and the first lens assembly changes, the second lens assembly can be moved correspondingly to realize the grouping focusing, so as to facilitate the focusing of the light projector using the telecentric lens, thereby being able to match different positions of the light source module without adjusting the positional relationship between the light source module and the first lens.

[0135] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0136] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the above specific embodiments, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application.

Claims

1. An internal reflection light projector characterized by comprising: The light source module and the telecentric lens are sequentially arranged along an optical path; the telecentric lens comprises a first lens assembly, a reflecting device and a second lens assembly; The light source module is configured to emit a plurality of discrete collimated light beams; The first lens assembly comprises a first lens; the image side of the first lens is arranged with the reflecting device; The first lens assembly is configured to receive the discrete collimated light beams, and concentrate the discrete collimated light beams so that the discrete collimated light beams are concentrated on the stop position of the second lens assembly after being reflected by the reflecting device; The second lens assembly is configured to receive the discrete collimated light beams reflected by the reflecting device, and change the focusing plane by moving along the optical axis direction to realize the switching between the point light array and the surface light array of the projected discrete collimated light beams; The second lens assembly comprises a second lens, a third lens and a fourth lens sequentially arranged along an optical path; The image side of the second lens is arranged with the reflecting device, the image side of the second lens is arranged with the third lens, and the image side of the third lens is arranged with the fourth lens; The first lens has positive refractive power, the second lens has positive refractive power, the third lens has positive refractive power, and the fourth lens has negative refractive power.

2. The internal reflection light projector according to claim 1, wherein The object side and the image side of the first lens are convex structures; The object side of the second lens is convex, and the image side is concave; The object side of the third lens is concave, and the image side is convex; The object side of the fourth lens is concave, and the image side is convex.

3. The internal reflection light projector according to claim 1, wherein The chief rays at different image heights of the object plane of the telecentric lens are parallel to the optical axis of the first lens.

4. The internal reflection light projector according to claim 1, wherein The reflecting surface of the reflecting device is a metal layer or a dielectric film coating.

5. The internal reflection light projector according to claim 1, wherein The reflecting surface of the reflecting device is an internal total reflection surface of a prism.

6. The internal reflection type light projector according to claim 1, wherein The reflecting surface of the reflecting device is a plane arranged between the optical paths of the first lens and the second lens, and is inclined by 40° to 50° with respect to the optical axes of the first lens, the second lens, the third lens and the fourth lens; The reflecting device is configured to project the discrete collimated light beams emitted by the first lens after being reflected by 90°.

7. The internal reflection light projector according to claim 1, wherein The optical distance between the first lens and the second lens and the size of the reflecting device satisfy the following conditional formula: 。 8. The internal reflection light projector according to claim 1, wherein A stop is arranged between the second lens and the third lens, so that the telecentric lens satisfies the following conditional formula: 73° < FOV < 112°, wherein FOV is the field of view of the telecentric lens; 0.95 < VP < 1, wherein VP is the depth of view of the telecentric lens; |Distortion| < 8%, wherein Distortion is the optical distortion of the optical system. The first lens, the second lens, the third lens and the fourth lens are made of aspheric plastic lenses; The refractive index nd of the first lens, the second lens, the third lens and the fourth lens satisfies the following formula: 1.62 < nd < 1.69, wherein nd is the refractive index of the lens at a wavelength of 587.6 nm.

9. The internal reflection light projector according to claim 1, wherein ​ ​ ​ ​ 10. The internal reflection light projector according to claim 1, wherein The second lens assembly is capable of moving along the optical axis direction, changing the optical distance between the first lens assembly and the second lens assembly to change the object side focal length of the telecentric lens, and realizing focusing on different image plane positions; When the distance between the light source module and the first lens assembly decreases, the second lens assembly is moved to the direction close to the reflecting device; When the distance between the light source module and the first lens assembly increases, the second lens assembly is moved to the direction away from the reflecting device.

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