Detection lens and detection method for head-mounted display device

Abstract

The present invention discloses a detection lens and a detection method for a head-mounted display device. The detection lens has a light incident end, and is configured to receive light from the light incident end; the detection lens includes a lens group, and the entrance pupil of the lens group as a whole coincides with its own aperture stop; the lens group comprises a first lens group and a second lens group, along the axial direction of the detection lens, the first lens group is closer to the light incident end relative to the second lens group, the effective focal length range of the first lens group is 20mm-40mm, the magnification range of the second lens group is 0.5-2 times, and the effective focal length range of the second lens group is 195mm-285mm; the second lens group includes a double Gauss lens group, the double Gauss lens group is located near the light incident end in the second lens group, and the double Gauss lens group is configured with at least three Gauss lenses with positive optical power on one side near the light incident end; the lateral field of view angle of the detection lens is less than or equal to 120 degrees, and the longitudinal field of view angle of the detection lens is less than or equal to 80 degrees.

Description

Technical Field

[0001] The present invention relates to the field of optics, and in particular to a detection lens and a detection method for a head-mounted display device. Background Art

[0002] Consumer electronics have become a major market trend in recent years. Virtual reality (VR) and augmented reality (AR) devices, in particular, are gaining widespread popularity due to their unique display effects, which immerse users in exceptional visual and audio experiences. However, in practice, VR and AR devices produce imaging that differs from traditional televisions and monitors because their displays are located very close to the human eye. Therefore, the display effects of VR and AR devices require specialized inspection lenses for testing.

[0003] Existing display inspection lenses often cannot meet the detection function of this close-range display, which requires simulating the close-range visual method of the human eye.

[0004] Therefore, it is necessary to improve the detection lens used for detection. Summary of the Invention

[0005] One purpose of the embodiments of the present disclosure is to provide a new technical solution for detecting the display effect of a head-mounted display device.

[0006] To achieve the purpose of this disclosure, the present disclosure provides the following technical solutions:

[0007] According to one aspect of the present disclosure, a detection lens for a head-mounted display device is provided.

[0008] The detection lens has a light incident end, and the detection lens is configured to receive light from the light incident end;

[0009] The detection lens includes a lens group, and the entrance pupil of the lens group as a whole coincides with its own aperture stop;

[0010] The lens group comprises a first lens group and a second lens group, wherein along the axial direction of the detection lens, the first lens group is closer to the light incident end than the second lens group, the effective focal length of the first lens group is in the range of 20 mm to 40 mm, the magnification of the second lens group is in the range of 0.5 to 2 times, and the effective focal length of the second lens group is in the range of 195 mm to 285 mm;

[0011] The second lens group includes a double Gauss lens group, the double Gauss lens group is located near the light incident end in the second lens group, and the double Gauss lens group is configured with at least three Gauss lenses with positive optical power on a side near the light incident end;

[0012] The transverse viewing angle of the detection lens is less than or equal to 120 degrees, and the longitudinal viewing angle of the detection lens is less than or equal to 80 degrees.

[0013] Optionally, the effective focal length of the first lens group is in the range of 22 mm to 25 mm.

[0014] Optionally, the magnification of the second lens group ranges from 0.6 to 1.0 times.

[0015] Optionally, the first lens group includes three condensing lenses, which are respectively a first condensing lens, a second condensing lens and a third condensing lens. The first condensing lens is closer to the light incident end than the second condensing lens, and the second condensing lens is closer to the light incident end than the third condensing lens.

[0016] The curvature radius of the light incident surface of the first condenser lens ranges from -20.5 mm to -21.9 mm, the curvature radius of the light exit surface of the first condenser lens ranges from -17.7 mm to -18.5 mm, and the thickness of the first condenser lens ranges from 10.4 mm to 11.3 mm;

[0017] The distance between the first condenser lens and the second condenser lens is 0.3 mm;

[0018] The curvature radius of the light incident surface of the second condenser lens ranges from -50.3 mm to -51.8 mm, the curvature radius of the light exit surface of the second condenser lens ranges from -34.1 mm to -34.9 mm, and the thickness of the second condenser lens ranges from 8.5 mm to 8.8 mm;

[0019] The distance between the second condenser lens and the third condenser lens ranges from 0.3 mm to 0.7 mm;

[0020] The curvature radius of the light incident surface of the third condensing lens ranges from -160 mm to -300 mm, the curvature radius of the light exit surface of the third condensing lens ranges from -60 mm to -80 mm, and the thickness of the third condensing lens ranges from 8.0 mm to 8.7 mm.

[0021] Optionally, the curvature radius of the light incident surface of the first condensing lens is -21.69 mm, the curvature radius of the light exit surface of the first condensing lens is -18.24 mm, and the thickness of the first condensing lens is 11.13 mm;

[0022] The curvature radius of the light incident surface of the second condenser lens is -50.44 mm, the curvature radius of the light exit surface of the second condenser lens is -34.70 mm, and the thickness of the second condenser lens is 8.72 mm;

[0023] The distance between the second condenser lens and the third condenser lens is 0.62 mm;

[0024] The curvature radius of the light incident surface of the third condensing lens is -171.77 mm, the curvature radius of the light exiting surface of the third condensing lens is -67.35 mm, and the thickness of the third condensing lens is 8.25 mm.

[0025] Optionally, the curvature radius of the light incident surface of the first condensing lens is -20.74 mm, the curvature radius of the light exit surface of the first condensing lens is -17.87 mm, and the thickness of the first condensing lens is 10.53 mm;

[0026] The curvature radius of the light incident surface of the second condenser lens is -51.62 mm, the curvature radius of the light exit surface of the second condenser lens is -34.26 mm, and the thickness of the second condenser lens is 8.65 mm;

[0027] The distance between the second condenser lens and the third condenser lens is 0.30 mm;

[0028] The curvature radius of the light incident surface of the third condensing lens is -287.14 mm, the curvature radius of the light exiting surface of the third condensing lens is -74.95 mm, and the thickness of the third condensing lens is 8.51 mm.

[0029] Optionally, the focusing lens is a meniscus lens.

[0030] Optionally, the second lens group includes a collimating lens group, and the double Gauss lens group is closer to the light incident end relative to the collimating lens group.

[0031] Optionally, the diameters of the first lens group and the second lens group are less than or equal to 65 mm.

[0032] Optionally, the double Gaussian lens group includes three Gaussian lenses, namely a first Gaussian lens, a second Gaussian lens, and a third Gaussian lens;

[0033] The curvature radius of the light incident surface of the first Gaussian lens ranges from 59.5 mm to 62.5 mm, the curvature radius of the light exit surface of the first Gaussian lens ranges from -165.5 mm to -156.7 mm, and the thickness of the first Gaussian lens ranges from 14.0 mm to 15.0 mm;

[0034] The distance between the first Gaussian lens and the second Gaussian lens is 0.3 mm;

[0035] The curvature radius of the light incident surface of the second Gaussian lens ranges from 36.0 mm to 39.0 mm, the curvature radius of the light exit surface of the second Gaussian lens ranges from 60.0 mm to 66.0 mm, and the thickness of the second Gaussian lens ranges from 13.0 mm to 14.0 mm;

[0036] The distance between the second Gauss lens and the third Gauss lens ranges from 3.0 mm to 3.2 mm;

[0037] The curvature radius of the light incident surface of the third Gaussian lens ranges from 153.0 mm to 156.9 mm, the curvature radius of the light exit surface of the third Gaussian lens ranges from 23.5 mm to 25.3 mm, and the thickness of the third Gaussian lens ranges from 7.8 mm to 8.3 mm.

[0038] Optionally, the first lens group is configured to be movable as a whole along the axial direction of the detection lens.

[0039] The present invention also provides a detection method for a head-mounted display device, comprising:

[0040] Using the above-mentioned detection lens;

[0041] Aim the light incident end of the test lens at the head-mounted display device to be tested;

[0042] Adjust the light incident end of the detection lens along the axial direction of the detection lens to a position where the light incident end coincides with the exit pupil projected by the head-mounted display device to be tested;

[0043] The detection lens is used to collect images projected by the head-mounted display device to be tested.

[0044] One technical benefit of the disclosed embodiments is that the inspection lens simulates close-up visual perception by the human eye, enabling inspection of head-mounted display devices that display content at close range. By configuring the lens assembly, the inspection lens controls the horizontal field of view to 120 degrees and the vertical field of view to 80 degrees, enabling inspection of head-mounted display devices with widescreen displays. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] 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 or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0046] Figure 1 This is a schematic diagram of a lens assembly according to a specific embodiment of the present invention;

[0047] Figure 2(a) to Figure 2(c) for Figure 1 A schematic diagram of imaging parameters of a detection lens according to the illustrated embodiment;

[0048] Figure 3 is a schematic diagram of a lens assembly according to another specific embodiment of the present invention;

[0049] Figure 4(a) to Figure 4(c) for Figure 3 Schematic diagram of imaging parameters of the detection lens in the embodiment. DETAILED DESCRIPTION

[0050] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0051] The present invention provides a detection lens for a head-mounted display device. The detection lens comprises a lens group, which comprises a first lens group and a second lens group.

[0052] The detection lens has a light incident end. In actual application, the light incident end of the detection lens faces the display device to be detected, and light enters the detection lens from the light incident end. The entrance pupil of the lens group as a whole coincides with its own aperture stop. In actual application, the position of the projected image of the display to be tested corresponds to the position of the light incident end of the detection lens, and the image light emitted by the display to be tested enters the detection lens from the light incident end. The detection lens provided by this technical solution can simulate the close-range visual characteristics of the human eye. The light exit hole of the display to be tested coincides with the light incident end of the detection lens along the optical axis direction. This design method conforms to the characteristics of human eye viewing.

[0053] The detection lens is provided with a lens group, the entrance pupil of the lens group as a whole coincides with its own aperture stop. This optical system conforms to the optical form of the human eye and can better simulate the observation conditions of the human eye. The lens group includes a first lens group and a second lens group. Figure 1 As shown, the light input end of the detection lens is used to receive light, and light is emitted from the light output end. An optical sensor can be located at the light output end to receive an image. The first lens group and the second lens group are arranged in sequence from the light input end to the light output end. That is, the first lens group is located on the side of the second lens group closest to the light input end.

[0054] The first lens group is mainly used to collect and focus the light emitted by the head-mounted display device. Optionally, the first lens group includes at least two condenser lenses, the focal length of which is positive and can focus the light incident from the incident end into a certain range, such as Figure 1 As shown, the focal length of the condenser lens is positive. After being processed by the condenser lens, the scattered light at the incident end is converged into the detection lens and propagates toward the light output end. The light that enters the detection lens is then optically processed by subsequent lenses, resulting in imaging on the optical sensor.

[0055] The second lens group is used to perform optical processing on the light entering the detection lens to correct the aberration of the image projected by the display device. Figure 1 As shown in FIG2 , the second lens group processes aberrations such as spherical aberration and astigmatism through multiple lenses.

[0056] Optionally, the second lens group may include a double Gauss lens group and a collimating lens group, and the double Gauss lens group and the collimating lens group jointly form an adjustment effect on the above-mentioned aberrations. The double Gauss lens can be mainly used to adjust the aberrations caused by the asymmetry of the optical system, while the collimating lens is used to correct the light to tend to parallel light.

[0057] In this technical solution, if Figure 1 As shown, along the direction from the light input end to the light output end, the double Gaussian lens group is located closer to the light input end. That is, the double Gaussian lens group is closer to the light input end than the collimating lens group. The double Gaussian lens group includes at least three Gaussian lenses with positive optical power, and these three Gaussian lenses are located closer to the light input end in the double Gaussian lens group. The above-mentioned three Gaussian lenses can be a first Gaussian lens, a second Gaussian lens, and a third Gaussian lens. The three Gaussian lenses are used to converge the light projected by the first lens group toward the center of the optical axis.

[0058] Optionally, the overall effective focal length of the first lens group can be selected to range from 20mm to 40mm, and the overall effective focal length of the second lens group can be selected to range from 50mm to 500mm. Preferably, the range can be within 195mm-285mm. The overall effective focal length of the first lens group and the second lens group is coordinated so that the lateral field of view angle of the detection lens is less than or equal to 120 degrees, and the longitudinal field of view angle is less than or equal to 80 degrees. This design makes the detection field of view of the detection lens relatively wide, which is suitable for shooting head-mounted display devices with widescreen display effects. It can perform effect detection on the display image of the head-mounted display device at a close distance. The magnification range of the second lens group can be optionally controlled between 0.5-2 times. Through this magnification range, the second lens group can play a certain degree of zooming effect on the image while reducing image aberrations, thereby achieving an appropriate detection effect.

[0059] This solution first designs the entrance pupil and aperture stop of the lens group to overlap, effectively simulating the optical state of the human eye when actually observing the head-mounted display test lens. During actual testing, the position of the image projected by the head-mounted display device can be adjusted to a position that overlaps with the light input end. When the head-mounted display device displays the image, in order to enable the human eye to observe it, the head-mounted display device will project the image at a predetermined position through the internal lens. Aligning this position with the light input end can well simulate the observation state of the human eye. When using the test lens provided by this solution for testing, the light input end of the test lens can be brought close to the head-mounted display device and positioned in line with the projected image. In this way, the state of the test lens when capturing the image can be consistent with the state of the human eye observing the image.

[0060] Furthermore, the entrance pupil of the detection lens of this solution coincides with its own aperture stop, which results in a lens being provided only on one side of the aperture stop along the direction from the light input end to the light output end. This positional relationship causes the optical system to be asymmetric on both sides of the aperture stop, and this imaging method is more prone to aberration. To address this, this solution arranges a first lens group in the detection lens, which can also serve as a role in providing an intermediate image for the second lens group. That is, Figure 1 As shown, after optical processing by the first lens group, the first lens group can form an image of the AR or VR device between the first and second lens groups. The second lens group receives the real image between the first and second lens groups and further performs aberration processing. Forming a real image between the first and second lens groups helps address the issue of optical system asymmetry. The real image formed between the first and second lens groups corresponds to the entrance pupil of the second lens group.

[0061] The detection lens provided by this solution can more accurately simulate the viewing state of the human eye, effectively and accurately detecting the close-up display of head-mounted display devices. Furthermore, the detection lens has a wide field of view, which can complete the display effect detection of VR and AR head-mounted display devices with widescreen display effects in one go, without having to adjust the relative position of the display device and the detection lens.

[0062] The head-mounted display devices mentioned in this solution can be virtual reality (VR) devices, augmented reality (AR) devices, and other devices that require users to wear them on their heads and view them from a close distance. These devices often suffer from the inability to effectively simulate human visual perception during inspection. The inspection lens provided in this solution can address this simulation issue.

[0063] Optionally, the effective focal length of the first lens group can be in the range of 22mm to 25mm. This makes it easier for the detection lens to form a larger field of view, bringing the field of view angle close to 120 degrees. If the effective focal length of the first lens group is too small, light rays from an excessively large angle range will be collected, making it more difficult for subsequent lenses to handle field aberrations. This will also affect the number of lenses in the first and second lens groups and their length along the detection lens direction. If the effective focal length of the first lens group is too large, the diameters of the first lens group and the detection lens need to be adjusted to bring the field of view angle into the appropriate range. Moreover, an excessively long focal length makes it difficult for the detection lens to achieve a field of view angle close to 120 degrees. In an embodiment where the effective focal length of the first lens group falls within the above range, in combination with a second lens group with an effective focal length range of 195mm-285mm, images with a field of view angle less than or equal to 120*80 degrees can be accurately captured and imaged. When the effective focal length range of the second lens group matches that of the first lens group within the above range, the imaging accuracy is higher, enabling more effective detection of the imaging effect of the head-mounted display device.

[0064] Optionally, the magnification range of the second lens group can be between 0.6-1.0 times. Within this range, the second lens group can more reliably perform aberration correction on the real image with a large field angle formed by the first lens group. If the magnification of the second lens group is too large, the size of the aberration that needs to be corrected will also increase, which will increase the difficulty of aberration correction. In order to correct larger aberrations, the diameter of the second lens group may need to be increased, and the number of lenses included may also need to be increased. If the magnification of the second lens group is too small, the aberration that needs to be adjusted and corrected is too subtle, which will increase the precision requirements for the lenses in the second lens group. If the lens molding accuracy in the second lens group is not enough, it may not be possible to adjust subtle aberrations. Therefore, this solution preferably uses a second lens group with a magnification between 0.7-1.3 times to better achieve aberration correction.

[0065] Optionally, in a specific embodiment, the effective focal length of the first lens group is 23.4 mm, the effective focal length of the second lens group is 235 mm, and the magnification of the second lens group is 0.72. In this embodiment, the detection lens can accurately detect the light image projected by the head-mounted display device within a horizontal field of view of 120 degrees and a vertical field of view of 80 degrees, and correct for aberrations caused by its own image acquisition.

[0066] Figure 2 shows the field aberration diagram formed by the embodiment for light of different wavelengths. Figure 2(a) is a longitudinal spherical aberration diagram, which reflects the effect of the detection lens as a whole on the longitudinal spherical aberration formed on the light. The first lens group and the second lens group of the embodiment limit the spherical aberration within a limited range. Figure 2(b) is an astigmatism field curve diagram, which reflects the effect of the detection lens as a whole on the astigmatism formed on the light. The first lens group and the second lens group of the embodiment limit the astigmatism to a smaller extent. Figure 2(c) is a distortion diagram for the distortion effect of the body detection lens as a whole on the image formation. In this embodiment, the first lens group and the second lens group project the image light in the form of barrel distortion so that the image light within the entire field of view angle range can be projected on the image sensor 4.

[0067] The different lines in Figure 2(a) to (c) represent light with different wavelengths.

[0068] Optionally, the detection lens includes an image sensor 4, which is disposed at the light-emitting end of the detection lens and is used to receive light and images processed by the detection lens. The image sensor 4 forms an image projected by the head-mounted display device to analyze the display effect.

[0069] In the above embodiment, the image sensor 4 may optionally have pixels smaller than or equal to 4.5 microns, and its color registration may be controlled to be smaller than or equal to 7.9 microns. Using an image sensor 4 with pixels smaller than or equal to 4.5 microns generally enables clear capture of the macro display image, facilitating analysis and detection of the display effect. In practical applications, an image sensor 4 with even smaller pixels may also be used.

[0070] Optionally, the focusing lens is preferably a meniscus lens. When the focusing lens has positive optical power, it is further formed into a meniscus lens. This design can further improve the focusing effect of the focusing lens, so that the light within the predetermined field of view angle range is focused as much as possible by the focusing lens into the detection lens. The edge portion of the meniscus lens is bent and extended relative to the center portion, thereby making it easier to collect and converge large-angle light. In addition, the meniscus lens with positive optical power has a relatively thin thickness at the edge and the curvature radius of the light incident surface and the light exit surface is relatively close, so the chromatic aberration of the lens is relatively small, and the aberration generated after the light passes through is relatively small. This design reduces the difficulty of aberration correction for subsequent lens groups.

[0071] Optionally, the first and second lens groups can form a flattening lens group (f-tan(theta) lens) or a fisheye lens group (f-theta lens). The flattening lens group produces a low-distortion, flattened image. This lens group evenly utilizes the pixels of image sensor 4 to display the projection effect of the head-mounted display device for subsequent analysis.

[0072] The final imaging effect of the fisheye lens group is highly distorted, and the image is barrel-shaped. The central area of ​​the image is imaged normally, while the surrounding area presents a curved, annularly deformed image. This form of distortion of the fisheye lens group helps to increase the overall field of view of the detection lens, which can be used to detect images within a larger field of view. The image projected by the head-mounted display device to be detected may have a larger field of view relative to the human eye at the observation position. In order to be able to detect the display image within a larger field of view, the detection lens also needs to have detection performance with a large field of view.

[0073] Optionally, for the implementation using a fisheye lens group "f-theta lens", this technical solution provides two sets of implementation plans.

[0074] In the first embodiment, the first lens group may include three condensing lenses, namely a first condensing lens 11, a second condensing lens 12 and a third condensing lens 13. Figure 1 As shown, the first condensing lens 11, the second condensing lens 12 and the third condensing lens 13 are arranged in sequence along the direction from the light input end to the light output end. The first condensing lens 11 is located on the side of the second condensing lens close to the light input end.

[0075] The following is as follows Figure 1 The fisheye lens assembly shown illustrates the present technical solution.

[0076] The first condensing lens 11 , the second condensing lens 12 and the third condensing lens 13 converge light within a range of a viewing angle less than or equal to 120*80 degrees into the detection lens to collect the light.

[0077] Optionally, the curvature radius of the light incident surface of the first condensing lens 11 ranges from -20.5mm to -21.9mm, the curvature radius of the light exit surface of the first condensing lens 11 ranges from -17.7mm to -18.5mm, and the thickness of the first condensing lens 11 ranges from 10.4mm to 11.3mm.

[0078] For example, in one embodiment, the curvature radius of the light incident surface of the first condensing lens 11 is -21.69 mm, the curvature radius of the light exiting surface of the first condensing lens 11 is -18.24 mm, and the thickness of the first condensing lens 11 is 11.13 mm.

[0079] Optionally, the curvature radius of the light incident surface of the second condensing lens 12 ranges from -50.3 mm to -51.8 mm, the curvature radius of the light exiting surface of the second condensing lens 12 ranges from -34.1 mm to -34.9 mm, and the thickness of the second condensing lens 12 ranges from 8.5 mm to 8.8 mm.

[0080] For example, in one embodiment, the curvature radius of the light incident surface of the second condensing lens 12 is -50.44 mm, the curvature radius of the light emitting surface of the second condensing lens 12 is -34.70 mm, and the thickness of the second condensing lens 12 is 8.72 mm.

[0081] Optionally, the curvature radius of the light incident surface of the third condensing lens 13 ranges from -160 mm to -300 mm, the curvature radius of the light exiting surface of the third condensing lens 13 ranges from -60 mm to -80 mm, and the thickness of the third condensing lens 13 ranges from 8.0 mm to 8.7 mm.

[0082] For example, in one embodiment, the curvature radius of the light incident surface of the third condensing lens 13 is -171.77 mm, the curvature radius of the light exiting surface of the third condensing lens 13 is -67.35 mm, and the thickness of the third condensing lens 13 is 8.25 mm.

[0083] Optionally, the distance between the first condensing lens 11 and the second condensing lens 12 is 0.3 mm. Optionally, the distance between the second condensing lens 11 and the third condensing lens 12 is 0.62 mm.

[0084] In the above embodiment, the three focusing lenses can accurately converge light with a field of view angle within the range of about 120 degrees * 80 degrees into the detection lens, and parallelize the irradiation direction of the light so that the light is irradiated onto the subsequent lens while producing as little aberration as possible. If the curvature radius of the light incident surface and the light exit surface of the first focusing lens 11, the second focusing lens 12, and the third focusing lens 13 differ greatly from the above range, it is possible that the aberration generated after the image light passes through the focusing lens will increase, thereby increasing the difficulty of subsequently eliminating the aberration. The focal length of the first focusing lens 11 is smaller than the focal length of the second focusing lens 12, and the focal length of the second focusing lens 12 is smaller than the focal length of the third focusing lens 13. After the light enters from the light incident end, it can gradually propagate in the direction close to the axis of the detection lens, and the light tends to be parallel. This moderate refractive effect helps to reduce the aberration generated between light of different wavelengths.

[0085] In addition to the first condensing lens 11 , the second condensing lens 12 , and the third condensing lens 13 , the first lens group may further include a plurality of lenses, so that light can form an intermediate real image after passing through the first lens group.

[0086] In an optional embodiment, the first lens group includes the above-mentioned first focusing lens 11, second focusing lens 12 and third focusing lens 13, and two primary collimating lenses, and the two primary collimating lenses are lens 14 and lens 15 in the following table in the direction from the light input end to the light output end.

[0087] Table 1 below shows the parameters of each lens in the first lens group in this embodiment:

[0088]

[0089] Table 1

[0090] Table 1 shows an implementation of the present invention using a fisheye lens group "f-theta lens". Figure 1 As shown. Among them, the light-emitting end side of the lens 15 is the real image of the first lens group in the detection lens, and the distance along the optical axis between the lens 15 and the real image is 9.584532mm. On the light-incoming end side of the first focusing lens 11 is the real image (exit pupil) projected by the head-mounted display device, and the distance along the optical axis between the real image and the first focusing lens 11 is 8.041887mm. In particular, in the present technical solution, the light-incoming end and the real image projected by the head-mounted display device are in the same position, that is, the distance between the light-incoming end and the first focusing lens 11 can also be 8.041887mm. As Figure 1 As shown, the field of view of this optional embodiment is approximately 120 degrees * 80 degrees.

[0091] As described above, the second lens group is used to compensate for the aberrations generated during the overall imaging process, and ultimately forms an image on the image sensor 4 located at the light output end. Optionally, the second lens group may include a double Gauss lens group and a collimating lens group.

[0092] Optionally, the double Gaussian lens group includes at least three Gaussian lenses, the first three Gaussian lenses being a first Gaussian lens 21, a second Gaussian lens 22, and a third Gaussian lens 23. The three Gaussian lenses are arranged in sequence along the direction from the light input end to the light output end.

[0093] Optionally, the curvature radius of the light incident surface of the first Gaussian lens 21 ranges from 59.5 mm to 62.5 mm, the curvature radius of the light exit surface of the first Gaussian lens 21 ranges from -165.5 mm to -156.7 mm, and the thickness of the first Gaussian lens 21 ranges from 14.0 mm to 15.0 mm.

[0094] For example, in one embodiment, the curvature radius of the light incident surface of the first Gaussian lens 21 is 60.8 mm, the curvature radius of the light exit surface of the first Gaussian lens 21 is -164.1 mm, and the thickness of the first Gaussian lens 21 is 14.5 mm.

[0095] Optionally, the curvature radius of the light incident surface of the second Gaussian lens 22 ranges from 36.0 mm to 39.0 mm, the curvature radius of the light emitting surface of the second Gaussian lens 22 ranges from 60.0 mm to 66.0 mm, and the thickness of the second Gaussian lens 22 ranges from 13.0 mm to 14.0 mm.

[0096] For example, in one embodiment, the curvature radius of the light incident surface of the second Gaussian lens 22 is 37.5 mm, the curvature radius of the light emitting surface of the second Gaussian lens 22 is 61.5 mm, and the thickness of the second Gaussian lens 22 is 13.6 mm.

[0097] Optionally, the curvature radius of the light incident surface of the third Gaussian lens 23 ranges from 153.0 mm to 156.9 mm, the curvature radius of the light exit surface of the third Gaussian lens 23 ranges from 23.5 mm to 25.3 mm, and the thickness of the third Gaussian lens 23 ranges from 7.8 mm to 8.3 mm.

[0098] For example, in one embodiment, the curvature radius of the light incident surface of the third Gaussian lens 23 is 154.5 mm, the curvature radius of the light exit surface of the third Gaussian lens 23 is 24.3 mm, and the thickness of the third Gaussian lens 23 is 7.9 mm.

[0099] Optionally, the distance between the first Gaussian lens 21 and the second Gaussian lens 22 is 0.3 mm. Optionally, the distance between the second Gaussian lens 22 and the third Gaussian lens 23 ranges from 3.0 mm to 3.2 mm. For example, the distance between the second Gaussian lens 22 and the third Gaussian lens 23 is 3.1 mm.

[0100] In such Figure 1 In the illustrated technical solution, the double Gaussian lens assembly can include eight lenses, of which the first five lenses converge light, and the last three lenses further adjust the light to form dispersed, relatively parallel rays. The eight lenses, along the direction from the light input end to the light output end, are Gaussian lens 21, Gaussian lens 22, Gaussian lens 23, Gaussian lens 24, Gaussian lens 25, Gaussian lens 26, Gaussian lens 27, and Gaussian lens 28.

[0101] Table 2 below presents the parameters of each lens of the double Gauss lens set in this embodiment:

[0102]

[0103] Table 2

[0104] Table 2 shows the Figure 1 The parameters of each lens of the double Gauss lens group of the fisheye lens group "f-theta lens" in the scheme shown. Figure 1 As shown. Among them, the light-emitting end side of lens 15 is the other lenses of the second lens group in the detection lens, and the distance along the optical axis between Gaussian lens 28 and the next lens is 23.180907mm. On the light-entering end side of Gaussian lens 21 is the real image (exit pupil) formed by the first lens group in the detection lens, and the distance along the optical axis between this real image and Gaussian lens 21 is 8.695056mm. In this technical solution, the double Gaussian lens group converges and then disperses the various colors of light in the image, which is used to achieve aberration compensation for light of different wavelengths and reduce the interference of aberration on imaging detection.

[0105] like Figure 1 As shown, the collimating lens group may include seven lenses. In this embodiment, the collimating lenses are collimating lens 31, collimating lens 32, collimating lens 33, collimating lens 34, collimating lens 35, collimating lens 36, and collimating lens 37, respectively, along the direction from the light input end to the light output end. The collimating lens group is used to converge the scattered light processed by the double Gauss lens group into a regionally parallel beam, and to converge the light of different colors of different wavelengths into a regionally parallel image again, so as to facilitate imaging on the image sensor 4 at the light output end.

[0106] Table 3 below shows the parameters of each lens of the collimating lens group in this embodiment:

[0107]

[0108] Table 3

[0109] Table 3 shows the Figure 1 The parameters of the collimating lens group of the fisheye lens group "f-theta lens" in the scheme shown are as follows. Figure 1 As shown. The collimating lens 37 faces the image sensor 4 on the light-emitting side, and the distance from the collimating lens 37 to the image sensor 4 along the optical axis is 77.035957 mm. Specifically, the collimating lens 37 has flat light-entry and light-exit surfaces with large radii of curvature, minimizing aberrations caused by light entering the collimating lens 37. The collimating lens 37 corrects the direction of image light, directing it toward the image sensor 4 in a manner that is close to parallel. On the light-entry side of the collimating lens 31 is the final Gaussian lens of the second lens group, namely, Gaussian lens 28.

[0110] Optionally, in this solution, different glass materials can be used for different lenses to achieve better optical effects. Different glass materials have different refractive indices and astigmatism effects on light of different wavelengths. The glass material can be selected from existing standard glass materials. Figure 1 Taking the technical solution shown as an example, for the first lens group, the glass number of the first condensing lens 11 is 946179, the glass number of the second condensing lens 12 is 805255, the glass number of the third condensing lens 13 is 835427, the glass number of the lens 14 is 805255, and the glass number of the lens 15 is 438945.

[0111] For the double Gauss lens group, the glass number of Gauss lens 21 is 438945, the glass number of Gauss lens 22 and Gauss lens 23 is 805255, the glass number of Gauss lens 24 is 717295, and the glass number of Gauss lens 25 is 946179, the glass number of Gauss lens 26 is 518590, the glass number of Gauss lens 27 is 805255, and the glass number of Gauss lens 28 is 835427.

[0112] For the collimating lens group, the glass number of collimating lens 31 is 438945, the glass number of collimating lens 32 is 923209, the glass number of collimating lens 33 is 805255, the glass number of collimating lens 34 is 438945, the glass number of collimating lens 35 is 593683, the glass number of collimating lens 36 is 805255, and the glass number of collimating lens 37 is 593683.

[0113] Figure 2 shows Figure 1The illustrated embodiment limits image aberrations. Figure 2(a) is a schematic diagram of longitudinal spherical aberration; Figure 2(b) is a schematic diagram of field astigmatism; and Figure 2(c) is a schematic diagram of distortion. This embodiment exhibits significant distortion, with the first and second lens groups forming a fisheye lens system.

[0114] Optionally, the first lens group can move along the axial direction of the detection lens, and can realize focus detection of the detection lens through axial movement, so that the image projected by the head-mounted display device to be detected can be accurately focused and imaged on the image sensor 4.

[0115] In a preferred embodiment, the second lens group is entirely movable along the axial direction of the detection lens. The second lens group has a relatively longer overall focal length, and its axial movement enables more precise focusing of the detection lens, facilitating accurate capture of the image projected by the head-mounted display device. This design minimizes imaging errors in the detection lens itself, thereby accurately reflecting the imaging effect of the head-mounted display device under test.

[0116] Optionally, in this technical solution, the aperture stop of the lens assembly itself has an aperture range of 3.8mm-4.2mm, preferably 4mm. On the one hand, the size of the aperture stop simulates the normal size of the human pupil; on the other hand, by controlling the size of the aperture stop, the field of view of the detection lens can also be auxiliary limited, simulating the actual working conditions of the head-mounted display device.

[0117] Optionally, the overall aperture of the first lens group and the second lens group is less than or equal to 40 mm, for example, it can be 35 mm or 38 mm. This design ensures that the diameter of the detection lens will not be too large, otherwise it will lead to the inability to bring the light incident end close to the exit pupil position of the head-mounted display device in actual application. The head-mounted display device often has a specific shape, and the space for placing the detection lens is limited. Since the aperture of the detection lens is relatively small, it is relatively difficult to achieve a relatively large field of view. In this case, the technical solution achieves a large field of view at a small diameter by configuring a first lens group with a focusing lens and a double Gauss lens group.

[0118] In another specific embodiment of this technical solution, Figure 3 Another embodiment using a fisheye lens assembly is shown below. Figure 3 The embodiment shown is for illustration of the present solution.

[0119] In the second embodiment, the first lens group may include three condensing lenses, namely a first condensing lens 11, a second condensing lens 12 and a third condensing lens 13. Figure 1As shown, the first condensing lens 11, the second condensing lens 12 and the third condensing lens 13 are arranged in sequence along the direction from the light input end to the light output end. The first condensing lens 11 is located on the side of the second condensing lens close to the light input end.

[0120] Optionally, in this embodiment, the curvature radius of the light incident surface of the first condenser lens 11 is -20.74 mm, the curvature radius of the light exit surface of the first condenser lens 11 is -17.87 mm, and the thickness of the first condenser lens 11 is 10.53 mm;

[0121] The radius of curvature of the light incident surface of the second condenser lens 12 is -51.62 mm, and the radius of curvature of the light exit surface of the second condenser lens 12 is -34.26 mm. The thickness of the second condenser lens 12 is 8.65 mm; the distance between the second condenser lens 12 and the third condenser lens is 0.30 mm. The radius of curvature of the light incident surface of the third condenser lens 13 is -287.14 mm, and the radius of curvature of the light exit surface of the third condenser lens 13 is -74.95 mm. The thickness of the third condenser lens 13 is 8.51 mm.

[0122] In the above-mentioned embodiment of the focusing lens, the first, second and third focusing lenses can accurately converge light with a horizontal field angle of about 120 degrees and a vertical field angle of about 80 degrees into the detection lens, and converge the irradiation direction of the light so that the light is irradiated onto the subsequent lens as a whole. In this process, barrel aberration can be generated. In the optical processing of the subsequent lens, barrel aberration will be further formed, and finally a distorted image will be formed. The advantage of this embodiment is that the desired field angle can be achieved by using fewer focusing lenses, or a larger number of focusing lenses can be used to obtain a very large field angle. In the edge area of ​​the formed image, in order to accommodate more light, a pixel point receives more light compared to the embodiment using a flat field lens. This also causes a relative change in the aberration detection of the edge area of ​​the image.

[0123] In addition to the first, second and third condensing lenses, the first lens group may further include a plurality of lenses, so that light can form an intermediate real image after passing through the first lens group.

[0124] In this embodiment, the first lens group includes the above-mentioned focusing lens and two primary collimating lenses, and the two primary collimating lenses are lens 14 and lens 15 in the following table in the direction from the light input end to the light output end.

[0125] Table 4 below shows the parameters of each lens in the first lens group in this embodiment:

[0126]

[0127]

[0128] Table 4

[0129] Table 4 shows another implementation of the fisheye lens group "f-theta lens" in this solution, such as Figure 3 As shown. Among them, the light-emitting end side of the lens 15 is the real image of the first lens group in the detection lens, and the distance between the lens 15 and the real image along the optical axis is 10.372304mm. On the light-incoming end side of the focusing lens is the real image (exit pupil) projected by the head-mounted display device, and the distance between the real image and the focusing lens along the optical axis is 8.302543mm. In particular, in the present technical solution, the light-incoming end and the real image projected by the head-mounted display device are in the same position, that is, the distance between the light-incoming end and the focusing lens can also be 8.302543mm. As Figure 3 As shown, the field of view of this optional embodiment is close to 120 degrees * 60 degrees.

[0130] As described above, the second lens group is used to compensate for the aberrations generated during the overall imaging process, and ultimately forms an image on the image sensor 4 located at the light output end. The second lens group may include a double Gauss lens group and a collimating lens group.

[0131] like Figure 3 As shown, the double Gaussian lens assembly can include eight lenses, of which the first five lenses converge the light, and the last three lenses further adjust the light to form dispersed, relatively parallel light. The eight lenses, along the direction from the light input end to the light output end, are Gaussian lens 21, Gaussian lens 22, Gaussian lens 23, Gaussian lens 24, Gaussian lens 25, Gaussian lens 26, Gaussian lens 27, and Gaussian lens 28.

[0132] Table 5 below presents the parameters of each lens of the double Gauss lens set in this embodiment:

[0133]

[0134]

[0135] Table 5

[0136] Table 5 shows the Figure 3 The parameters of each lens of the double Gauss lens group of the fisheye lens group "f-theta lens" in the scheme shown. Figure 3As shown. Among them, the light-emitting end side of the Gaussian lens 28 is the other lens of the second lens group in the detection lens, and the distance between the Gaussian lens 28 and the next lens along the optical axis is 34.865381mm. On the light-entering end side of the Gaussian lens 21 is the real image (exit pupil) formed by the first lens group in the detection lens, and the distance between the real image and the Gaussian lens 21 along the optical axis is 17.789416mm. In this technical solution, the double Gaussian lens group converges and then disperses the various colors of the image to achieve aberration compensation for light of different wavelengths and reduce the interference of aberration on imaging detection.

[0137] like Figure 3 As shown, the collimating lens group may include seven lenses. In this embodiment, the collimating lenses are collimating lens 31, collimating lens 32, collimating lens 33, collimating lens 34, collimating lens 35, collimating lens 36, and collimating lens 37, respectively, along the direction from the light input end to the light output end. The collimating lens group is used to converge the scattered light processed by the double Gauss lens group into a regionally parallel beam, and to converge the light of different colors of different wavelengths into a regionally parallel image again, so as to facilitate imaging on the image sensor 4 at the light output end.

[0138] Table 6 below presents the parameters of each lens of the collimating lens group in this embodiment:

[0139]

[0140]

[0141] Table 6

[0142] Table 6 shows the Figure 3 The parameters of the collimating lens group of the fisheye lens group "f-theta lens" in the scheme shown are as follows. Figure 3 As shown in the figure, the image sensor 4 is located on the light-emitting side of the collimating lens 37, and the distance from the collimating lens 37 to the image sensor 4 along the optical axis is 68.942486 mm. In particular, the light-emitting surface of the collimating lens 37 is nearly flat, minimizing the aberrations that occur after the light exits the collimating lens 37. The function of the collimating lens 37 is to correct the direction of the image light, converging it onto the image sensor 4. On the light-entering side of the collimating lens 31 is the final Gaussian lens of the second lens group, namely, Gaussian lens 25.

[0143] Optionally, in this solution, different glass materials can be used for different lenses to achieve better optical effects. Different glass materials have different refractive indices and astigmatism effects on light of different wavelengths. The glass material can be selected from existing standard glass materials. Figure 3Taking the technical solution shown as an example, for the first lens group, the glass number of the first focusing lens 11 is 946179, the glass number of the second focusing lens 12 is 805255, the glass number of the third focusing lens 13 is 835427, the glass number of the lens 14 is 805255, and the glass number of the lens 15 is 438945.

[0144] For the double Gauss lens group, the glass number of Gauss lens 21 is 438945, the glass number of Gauss lens 22 and Gauss lens 23 is 805255, the glass number of Gauss lens 24 is 717295, the glass number of Gauss lens 25 is 946179, the glass number of Gauss lens 26 is 518590, the glass number of Gauss lens 27 is 805255, and the glass number of Gauss lens 28 is 835427.

[0145] For the collimating lens group, the glass number of collimating lens 31 is 438945, the glass number of collimating lens 32 is 923209, the glass number of collimating lens 33 is 805255, the glass number of collimating lens 34 is 438945, the glass number of collimating lens 35 is 593683, the glass number of collimating lens 36 is 805255, and the glass number of collimating lens 37 is 593683.

[0146] Figure 4 shows Figure 3 The illustrated embodiment limits image aberrations. Figure 4(a) is a schematic diagram of longitudinal spherical aberration; Figure 4(b) is a schematic diagram of field astigmatism; and Figure 4(c) is a schematic diagram of distortion. This embodiment exhibits significant distortion, with the first and second lens groups forming a fisheye lens system.

[0147] This technical solution also provides a method for testing a head-mounted display device, comprising using the test lens of the above-described solution and aligning the test lens's incident light pattern with the display area of ​​the head-mounted display device under test. Preferably, the axis of the test lens is aligned with the display optical axis of the head-mounted display device under test.

[0148] Along the axial direction of the detection lens, the light incident end of the detection lens is adjusted to a position where it coincides with the exit pupil (real image) transmitted by the display device of the detection lens to be tested.

[0149] The above-mentioned detection lens is used to capture the image projected by the head-mounted display device to be tested. The captured image is then analyzed.

[0150] The above disclosure is only a preferred embodiment of the present disclosure, and certainly cannot be used to limit the scope of the rights of the present disclosure. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present disclosure are still within the scope of the invention.

Claims

1. A detection lens for a head-mounted display device, characterized in that: The detection lens has a light incident end, and the detection lens is configured to receive light from the light incident end; The detection lens includes a lens group, and the entrance pupil of the lens group as a whole coincides with its own aperture stop; The lens group is composed of a first lens group and a second lens group. Along the axial direction of the detection lens, the first lens group is closer to the light incident end than the second lens group. The effective focal length of the first lens group ranges from 20 mm to 40 mm, the magnification of the second lens group ranges from 0.5 to 2 times, and the effective focal length of the second lens group ranges from 195 mm to 285 mm. The first lens group is composed of five lenses, and the first lens, the second lens, the third lens, the fourth lens and the fifth lens are arranged in sequence from the light input end to the light output end. The optical focal power of the first lens is positive, the optical focal power of the second lens is positive, the optical focal power of the third lens is positive, the optical focal power of the fourth lens is negative, and the optical focal power of the fifth lens is positive. The second lens group is composed of a double Gauss lens group and a collimating lens group, and the double Gauss lens group is located near the light incident end in the second lens group. Wherein, the double Gaussian lens group is composed of 8 Gaussian lenses, and the first Gaussian lens, the second Gaussian lens, the third Gaussian lens, the fourth Gaussian lens, the fifth Gaussian lens, the sixth Gaussian lens, the seventh Gaussian lens and the eighth Gaussian lens are arranged in sequence from the light input end to the light output end. The optical focal power of the first Gaussian lens is positive, the optical focal power of the second Gaussian lens is positive, the optical focal power of the third Gaussian lens is negative, the optical focal power of the fifth Gaussian lens is negative, the optical focal power of the sixth Gaussian lens is negative, the optical focal power of the seventh Gaussian lens is positive, and the optical focal power of the eighth Gaussian lens is positive. The collimating lens group is composed of 7 collimating lenses, and a first collimating lens, a second collimating lens, a third collimating lens, a fourth collimating lens, a fifth collimating lens, a sixth collimating lens and a seventh collimating lens are sequentially arranged from the light input end to the light output end, the focal power of the first collimating lens is positive, the focal power of the second collimating lens is negative, the focal power of the third collimating lens is negative, the focal power of the fourth collimating lens is positive, the focal power of the fifth collimating lens is positive, the focal power of the sixth collimating lens is negative, and the focal power of the seventh collimating lens is positive, and The lateral viewing angle of the detection lens is less than or equal to 120 degrees, and the longitudinal viewing angle of the detection lens is less than or equal to 80 degrees.

2. The detection lens according to claim 1, characterized in that: The effective focal length of the first lens group is in the range of 22 mm to 25 mm.

3. The detection lens according to claim 1, characterized in that: The magnification of the second lens group ranges from 0.6 to 1.0 times.

4. The detection lens according to claim 1, characterized in that: The first lens, the second lens, and the third lens are meniscus lenses.

5. The detection lens according to claim 1, characterized in that: The double Gauss lens group is closer to the light incident end than the collimating lens group.

6. The detection lens according to claim 1, characterized in that: The diameters of the first lens group and the second lens group are less than or equal to 65 mm.

7. The detection lens according to claim 1, characterized in that: The curvature radius of the light incident surface of the first Gaussian lens ranges from 59.5 mm to 62.5 mm, the curvature radius of the light exit surface of the first Gaussian lens ranges from -165.5 mm to -156.7 mm, and the thickness of the first Gaussian lens ranges from 14.0 mm to 15.0 mm; The distance between the first Gaussian lens and the second Gaussian lens is 0.3 mm; The curvature radius of the light incident surface of the second Gaussian lens ranges from 36.0 mm to 39.0 mm, the curvature radius of the light exit surface of the first Gaussian lens ranges from 60.0 mm to 66.0 mm, and the thickness of the first Gaussian lens ranges from 13.0 mm to 14.0 mm; The distance between the second Gauss lens and the third Gauss lens ranges from 3.0 mm to 3.2 mm; The curvature radius of the light incident surface of the third Gaussian lens ranges from 153.0 mm to 156.9 mm, the curvature radius of the light exit surface of the third Gaussian lens ranges from 23.5 mm to 25.3 mm, and the thickness of the first Gaussian lens ranges from 7.8 mm to 8.3 mm.

8. The detection lens according to claim 1, characterized in that: The first lens group is configured to be movable as a whole along an axial direction of the detection lens.

9. A detection method for a head-mounted display device, characterized in that: include: Adopting the detection lens according to any one of claims 1 to 8; Aim the light incident end of the test lens at the head-mounted display device to be tested; Adjust the light incident end of the test lens along the axis of the lens to a position where it coincides with the exit pupil projected by the head-mounted display device to be tested; The detection lens is used to collect images projected by the head-mounted display device to be tested.

Images