AR waveguide sheet optical detection system

Abstract

The application discloses an AR waveguide sheet optical detection system, which comprises a projection module and an imaging module. The projection module comprises a plurality of projection assemblies, each of which comprises a projection lens, and the optical paths of the plurality of projection assemblies have one focus point. The imaging module comprises imaging assemblies corresponding to the projection assemblies one by one, each of which comprises an imaging lens, and the optical paths of the plurality of imaging assemblies have one focus point. The projection lens of the projection assembly and the imaging lens of the corresponding imaging assembly are mutually conjugate. The application makes the optical paths of the projection assembly and the imaging assembly converge at one point through active adjustment. The application can realize high-precision quantitative test imaging of important performances of the optical waveguide lens and projection modules independently, can be freely matched, debugged and tested, and is convenient for secondary development for different measured objects and realization of same-side or different-side measurement.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of optical detection, and particularly relates to an AR waveguide sheet optical detection system. BACKGROUND

[0002] With the rapid development of the AR industry, the AR augmented reality technology has great development potential in the military industry, the medical industry, the industrial detection industry and even the entertainment industry. Accordingly, higher requirements are put forward for AR product detection equipment, which not only needs to realize high-precision detection of product appearance, field of view, brightness, brightness uniformity and modulation transfer function and the like, but also needs to be capable of quick replacement to adapt to different products, different angles and configuration measurement requirements.

[0003] The optical waveguide sheet is a commonly used lens of AR glasses, and the AR glasses adopting the optical waveguide scheme are usually composed of a micro-projector, a diffractive optical waveguide and a human eye. Therefore, in the process of testing the optical waveguide sheet, a device simulating the functions of the micro-projector and the human eye is needed. At present, the device of this type usually needs to be specially customized, and the development cycle is long and the cost is high.

[0004] The optical performance testing device for the waveguide sheet as described in CN202011186782.4 can shield the edges of the waveguide sheet through the annular groove for accommodating the edges of the waveguide sheet, and the light shielding mechanism can shield the stray light at the edges of the waveguide sheet. However, the device has poor universality for different measured objects and is inconvenient for secondary development. SUMMARY

[0005] The application aims to provide an AR waveguide sheet optical detection system which is convenient for secondary development for different measured objects.

[0006] TECHNICAL SOLUTION: The AR waveguide sheet optical detection system comprises a projection module and an imaging module. The projection module comprises a plurality of projection assemblies, each of which comprises a projection lens. The light paths of the plurality of projection assemblies have one focal point. The imaging module comprises imaging assemblies corresponding to the projection assemblies one by one. Each imaging assembly comprises an imaging lens. The light paths of the plurality of imaging assemblies have one focal point. The projection lens of the projection assembly and the imaging lens of the corresponding imaging assembly are mutually conjugate. When the focal points of the light paths of the projection assembly and the imaging assembly coincide, the light paths of the projection assembly and the corresponding imaging assembly coincide. The distance from the focal point to the front end of the projection module is the same as the distance from the focal point to the front end of the imaging module.

[0007] Preferably, the projection module further comprises a projection base, the projection base being a spherical dome, and the projection assembly is installed on the projection base at a same position from the center of the sphere.

[0008] The projection assembly and the imaging assembly are provided with the spherical dome as the base, and when the projection assembly and the imaging assembly are debugged, only a small degree of debugging is needed, and the projection lens and the imaging lens can be easily conjugated.

[0009] Preferably, the projection assembly further comprises a light source assembly and a relay lens group, the light source assembly, the relay lens group and the projection lens are connected in sequence, and the imaging assembly further comprises an industrial camera connected to the imaging lens.

[0010] The light source assembly is used to provide a light source for the system, and the relay lens group is used to arrange the incident light of the light source assembly, so that the light source input is more uniform.

[0011] Preferably, the light source assembly comprises an LED light source, a collimating lens and a dichroic sheet, and the light of the LED light source passes through the collimating lens and the dichroic sheet in sequence to the relay lens group.

[0012] The collimating lens is used to arrange the incident light of the LED light source into parallel light, and then project it on the dichroic sheet with a transmissive and reflective function in the middle, and then transmit and reflect it through the dichroic sheet.

[0013] Preferably, the relay lens group comprises a relay outer cylinder, two groups of glue members are arranged in the relay outer cylinder, and a small aperture diaphragm with adjustable size is arranged in the middle of the glue member.

[0014] The size of the small aperture diaphragm can be adjusted according to requirements, so as to present different sizes of light spots at the center position of the light path, that is, at the focusing point where the projection assembly and the imaging assembly coincide during debugging.

[0015] Preferably, the imaging assembly and the projection assembly are provided with an inclination adjustment assembly, and a centering adjustment assembly and an inclination adjustment device are arranged between the industrial camera of the imaging assembly and the imaging lens.

[0016] The inclination adjustment assembly is used to adjust the inclination when the projection assembly and the imaging assembly are installed on the respective bases, and the centering adjustment assembly and the inclination adjustment assembly are used to complete the centering adjustment and the inclination adjustment between the camera and the lens, so that each imaging lens and its corresponding camera are in an excellent centering state after the centering operation.

[0017] Preferably, a negative cross line reticle is arranged at the front end of the relay lens group, and the negative cross line reticle is provided with a translation adjustment structure and a rotation adjustment structure.

[0018] The negative cross line scale plate is used as an object side, and can project an image on a camera in the system. The translation adjustment structure and the rotation adjustment structure are set to compensate for the slight errors caused by the machining of the optical element during active alignment, thereby affecting the debugging and imaging effect.

[0019] Preferably, the relay outer cylinder is connected to the projection lens through a hollow cylinder away from the light source assembly.

[0020] Working principle: The present application can make the light paths of the multi-channel projection assembly and the multi-channel imaging assembly converge at a point through active alignment. The detection system after debugging, the projection lens of the projection assembly and the imaging lens of the corresponding imaging assembly are mutually conjugated to form the test optical conditions of the waveguide sheet to be measured. The imaging and projection modules are independent after debugging. When used, the focal point of the projection assembly is aligned with the incident part of the AR waveguide sheet, and the focal point of the imaging assembly is aligned with the imaging part of the AR waveguide sheet. The light source presents a light spot on the AR waveguide sheet through the pinhole diaphragm. Since the imaging and projection modules are independent, the detection system is not limited to same-side or opposite-side measurement. The imaged light spot is converted into an electrical signal through a high-precision industrial camera. After an algorithm test process, the appearance and field of view angle, brightness, brightness uniformity and modulation transfer function of the important component light waveguide lens of the AR glasses are tested.

[0021] Advantages: Compared with the prior art, the present application has the following advantages: 1. The detection system can be freely debugged and tested on the rack, which is convenient for secondary development of different measured objects and realizes same-side or opposite-side measurement; 2. Compared with the existing similar detection equipment, the cost is lower and the measurement is more efficient. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is the overall structure principle diagram of the present application;

[0023] Figure 2 It is the projection assembly structure diagram of the present application;

[0024] Figure 3 It is the imaging assembly structure diagram of the present application;

[0025] Figure 4 It is the inclination adjustment structure diagram of the present application;

[0026] Figure 5 It is the centering adjustment structure diagram of the present application;

[0027] Figure 6 It is the imaging assembly adjustment tool schematic diagram of the present application;

[0028] Figure 7 It is the projection assembly adjustment tool schematic diagram of the present application;

[0029] Figure 8This is a schematic diagram illustrating the usage state of the present invention. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0031] like Figure 1 and Figure 8 The AR waveguide optical inspection system shown includes two optical modules: a projection module and an imaging module, which are used to simulate the micro-projector and the human eye in the actual application of AR glasses using an optical waveguide scheme, respectively.

[0032] The projection module includes nine projection components 1 and a projection base 5. Each projection component 1 includes a light source component 11, a relay lens group 12 and a projection lens 13. The light source component 11, the relay lens group 12 and the projection lens 13 are connected in sequence, and the optical path of the projection component 1 has a focal point.

[0033] The projection base 5 is a spherical dome. In this embodiment, there are a total of 9 projection components 1, that is, 9-channel projection components 1 are arranged on the lighting dome at corresponding angles. The projection components 1 are installed on the projection base 5 at the same position as the center of the sphere.

[0034] The light source assembly 11 includes an LED light source, a collimating lens 114, and a dichroic filter 115. The light from the LED light source passes sequentially through the collimating lens 114 and the dichroic filter 115 to the relay lens group 12. The LED light source is an RGB tri-color light source, and all three RGB light sources are point light sources, such as... Figure 2 As shown, the RGB three-color light source specifically consists of blue LED bead 111, green LED bead 112, and red LED bead 113. Each bead has two collimating lenses 114 at its front end. The collimating lenses 114 organize the incident light into parallel light, which is then projected onto a two-way color filter 115 in the middle that has transmission and reflection functions. After transmission and reflection by the two-way color filter 115, the output of the RGB three-color light source can be realized.

[0035] The relay lens group 12 is used to refine the incident light, making the light source input more uniform. The relay lens group 12 includes a relay outer cylinder 123, which contains two sets of adhesive components. An adjustable aperture 122 is located in the center of each adhesive component, and the size of the aperture 122 can be adjusted as needed. This results in light spots of different sizes appearing at the center position 4 of the optical path.

[0036] The front end of the relay lens group 12 is provided with a negative crosshair reticle 121, which is equipped with a translation adjustment structure and a rotation adjustment structure. The negative crosshair reticle 121 serves as the object plane, projecting an image onto the industrial camera 21 within the system. The translation and rotation adjustment structures are designed to compensate for minor errors in the optical component manufacturing process that could affect the adjustment and imaging results during active setup.

[0037] The end of the relay outer tube 123 away from the light source assembly 11 is connected to the projection lens 13 through the empty tube 124. The empty tube 124 has threads and high-precision shaft holes at both ends, which connect the relay lens tube, i.e., the relay outer tube 123, and the conjugate lens of the rear imaging lens 25, i.e., the projection lens 13. Specifically, it is connected to the lens tube 131.

[0038] The imaging module includes an imaging component 2 and an imaging base 6, which correspond one-to-one with the projection component 1. The imaging component 2 includes an imaging lens 25 and a camera 21. The camera 21 is connected to the imaging lens 25. The camera 21 is a high-precision industrial camera with a pixel size of 2.4μm×2.4μm, small size, light weight, and fast transmission speed.

[0039] The imaging base 6 is also a spherical dome. In this embodiment, there are nine imaging components 2, i.e., nine-channel imaging components 2 arranged at corresponding angles on the imaging dome. The imaging components 2 are mounted on the imaging base 6 at the same distance from the center of the sphere. Since the surface of the projection-side dome base is originally spherical, the platform is trimmed at the same distance from the center of the sphere at different spatial angles to serve as the mounting surface for each projection component 1. Similarly, the surface of the imaging-side dome base is originally spherical, and the platform is trimmed at the same distance from the center of the sphere at different spatial angles to serve as the mounting surface for each imaging component 2.

[0040] The optical path of projection component 1 also has a focal point. The projection lens 13 of projection component 1 and the imaging lens 25 of the corresponding imaging component 2 are conjugate to each other. When the focal points of projection component 1 and imaging component 2 coincide, the optical paths of the corresponding projection component 1 and imaging component 2 coincide. The distance from the center of the coincident optical path, i.e. the center position 4 of the optical path, to the front end of the projection module is the same as the distance from the center of the second optical path to the front end of the imaging module.

[0041] like Figure 3 As shown, a tilt adjustment component 24 is installed on the imaging component 2 and the projection component 1. A centering adjustment component 22 and a tilt adjustment device are provided between the industrial camera 21 and the imaging lens 25 of the imaging component 2. When the imaging component 2 is installed on the imaging base 6, or when the projection component 1 is installed on the projection base 5, the tilt adjustment component is used to adjust the tilt of the projection component 1 and the imaging component when they are installed on their respective bases. The centering adjustment component 22 and the tilt adjustment component 24 are used to perform centering adjustment and tilt adjustment on the imaging component 2, and to adjust the centering of the industrial camera 21 and the imaging lens 25 so that each imaging lens 25 is in a good centering state with its corresponding camera.

[0042] In this embodiment, the projection lens 13 and the imaging lens 25 are identical and conjugate to ensure that the centers of the optical paths on both sides coincide and the distance from the center of the optical path to the front end of both lenses is the same.

[0043] As shown in Figure 3 , the end face of the imaging lens 25 is also provided with an additional lens assembly 26, which is only used during adjustment.

[0044] The waveguide sheet optical detection system of the present application is adjusted during installation:

[0045] First, the bottom surface of the centering adjustment assembly 22 is used as a reference to adjust the sensor surface of the industrial camera 21 to be parallel to the bottom surface of the centering adjustment assembly 22, and then the entire set is connected with the imaging lens 25 at the bottom, which is connected perfectly through the shaft hole cooperation and does not need to be adjusted.

[0046] The tilt adjustment assembly 24 is used to adjust the two-dimensional tilt between the nine imaging assemblies 2 when the imaging dome is installed, which is composed of three plates, and two cylindrical pins are inserted from the side between each two plates, so that each two plates can adjust one-dimensional tilt, and after adjustment, it is locked by screw 23, and the three plates together constitute two-dimensional tilt adjustment, and the two-dimensional adjustment does not affect each other, and the same two-dimensional tilt adjustment assembly 24 is also provided on one side of the projection assembly 1.

[0047] As shown in Figure 6 , when all the imaging assemblies 2 and the projection assembly 1 are independently assembled, the imaging dome is assembled on the frame tool 82, a set of imaging adjustment assemblies is placed in the center hole, so that the central imaging assembly is centered with the cross line tool 81, and the central imaging assembly 2 and the cross line tool 81 are used as a reference to adjust the other eight imaging adjustment assemblies, so that all the optical centers fall on the cross line tool 81.

[0048] As shown in Figure 4 and Figure 5 , when the industrial camera 21 and the imaging lens 25 are assembled, the tilt adjustment device is used for tilt adjustment: the tilt adjustment device includes a camera adapter ring 221 and a camera reference ring 222, first, the industrial camera 21, the camera adapter ring 221 and the camera reference ring 222 are assembled, a small collimating light pipe 223 is sleeved on the camera reference ring 222, and it is considered that the cross line inside the small collimating light pipe 223 is parallel to the bottom surface of the camera reference ring 222, at this time, the cross line of the small collimating light pipe 223 is used as a reference to observe the imaging of the cross line inside the industrial camera 21, if there is a positional deviation, the tilt relationship is adjusted by inserting shims between the camera adapter ring 221 and the camera reference ring 222, until the cross line is completely coincident with the camera center. At this time, the small collimating light pipe 223 is removed, and the tilt relationship between the industrial camera 21 and the camera reference ring 222 is adjusted.

[0049] Centering adjustment: after the above-mentioned inclination adjustment, the relative position relationship adjustment of the industrial camera 21 and the centering adjustment assembly 22 assembly is completed, and the centering adjustment is to adjust the position relationship between the industrial camera 21 and the imaging lens 25. Similarly, the small collimating light pipe 223 is connected to the front end of the imaging lens 25, the imaging position of the cross line on the industrial camera 21 is observed, the imaging position of the cross line on the industrial camera 21 is adjusted by translating the industrial camera 21 and the centering adjustment assembly 22 assembly, until the cross line and the center of the industrial camera 21 almost coincide, and the two-part assembly is locked by the screw 23, and the centering adjustment is completed.

[0050] As shown in Figure 6 and Figure 7 , the entire frame tool 82 in the complete state is composed of 3 layers of frames, and different component adjustment purposes are achieved through the combination of different frames and the frame overturning. After the 9 imaging assemblies 2 are adjusted and centered, Figure 6 shows two layers of frames, and the third layer of frame is installed on the frame tool 82, and after the whole set is overturned, the uppermost layer is removed as Figure 7 , the projection assembly 1 can be adjusted.

[0051] Projection assembly 1 adjustment: after overturning, the projection dome and the imaging dome are first adjusted and centered, the middle projection assembly 1 is placed, and the 9 projection assemblies 1 are sequentially adjusted and fixed based on the imaging adjustment assembly.

[0052] At this point, the adjustment of the device can be considered complete, as shown in Figure 1 , the projection light 3 emitted from the front end of the projection assembly 1 is focused on the same point and then enters the corresponding imaging assembly 2, and when the device is developed again, the imaging module and the projection module can be arranged according to the needs, which can realize both opposite side measurement and same side measurement.

[0053] When in use, the middle part of the three-layer frame has a mounting plate 83, which can place the support 84 of the measured object. At the same time, the imaging module can be configured with an XY moving platform, so that the imaging module and the projection module are staggered with each other, so as to realize measurement on the optical waveguide sheet whose image coupling-in position and coupling-out position are not aligned, as shown in Figure 8 , which shows the measurement state, in the figure, the center of the first light path is aligned with the incident part 71 of the AR waveguide sheet 7 to be measured, and the center of the second light path is aligned with the imaging part 72 of the AR waveguide sheet, in this state, the light paths of the imaging module and the projection module still coincide through the AR waveguide sheet in the middle, the projection lens 13 and the imaging lens 25 are conjugate with each other, and through the cooperation of the high-precision industrial camera and the algorithm, the present application can realize high-precision quantitative testing of various important performances of the optical waveguide lens with high quality and high efficiency.

[0054] Finally, the application can realize high-definition imaging based on modulation transfer function; at a working distance of 250 mm, the spot presented by the optical path center has a single size of not more than 2 mm, and the overall size of 9 spots is not more than 3 mm; the angle centering repeatability data standard deviation of the projection imaging module at each angle position is less than 1.

Claims

1. An AR waveguide sheet optical detection system, comprising a projection module and an imaging module, characterized in that: The projection module comprises a plurality of projection assemblies (1), each of the projection assemblies (1) comprises a projection lens (13), and the optical paths of the plurality of projection assemblies (1) have one focal point; the imaging module comprises imaging assemblies (2) corresponding to the projection assemblies (1) one by one, each of the imaging assemblies (2) comprises an imaging lens (25), and the optical paths of the plurality of imaging assemblies (2) have one focal point; the projection lens (13) of the projection assembly (1) and the imaging lens (25) of the corresponding imaging assembly (2) are conjugate to each other, and when the focal points of the optical paths of the projection assembly (1) and the imaging assembly (2) coincide and the distance from the focal point to the front end of the projection module is the same as the distance from the focal point to the front end of the imaging module, the optical paths of the projection assembly (1) and the corresponding imaging assembly (2) coincide, and the distance from the focal point to the front end of the projection module is the same as the distance from the focal point to the front end of the imaging module; the projection module further comprises a projection base (5), the projection base (5) is a spherical dome, and the projection assemblies (1) are installed on the projection base (5) at positions away from the center of the sphere by the same distance; the imaging module further comprises an imaging base (6), the imaging base (6) is a spherical dome, and the imaging assemblies (2) are installed on the imaging base (6) at positions away from the center of the sphere by the same distance. 2.The AR waveguide sheet optical detection system of claim 1, wherein: The projection assembly (1) further comprises a light source assembly (11) and a relay lens group (12), the light source assembly (11), the relay lens group (12) and the projection lens (13) are connected in sequence, and the imaging assembly (2) further comprises a camera (21) connected to the imaging lens (25).

3. The AR waveguide sheet optical detection system of claim 2, wherein: The light source assembly (11) comprises an LED light source, a collimating lens (114) and a dichroic sheet (115), and the light of the LED light source passes through the collimating lens (114) and the dichroic sheet (115) to the relay lens group (12) in sequence.

4. The AR waveguide sheet optical detection system of claim 2, wherein: The relay lens group (12) comprises a relay outer cylinder (123), two groups of cementing members are arranged in the relay outer cylinder (123), and a small aperture diaphragm (122) with adjustable size is arranged in the middle of the cementing members.

5. The AR waveguide sheet optical detection system of claim 2, wherein: The imaging assembly (2) and the projection assembly (1) are provided with an inclination adjusting assembly (24), and the camera (21) of the imaging assembly (2) and the imaging lens (25) are provided with a centering adjusting assembly (22) and an inclination adjusting device.

6. The AR waveguide sheet optical detection system of claim 4, wherein, The front end of the relay lens group (12) is provided with a negative cross line scale plate (121), the negative cross line scale plate (121) is provided with a translation adjusting structure and a rotation adjusting structure.

7. The AR waveguide sheet optical detection system of claim 4, wherein: The end of the relay outer cylinder (123) away from the light source assembly (11) is connected to the projection lens (13) through a hollow cylinder (124).

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