Lens holder, lens assembly, camera module, video see-through device, and head-mounted display device

Abstract

A lens holder, a lens assembly, a camera module, a video see-through device, and a head-mounted display device. The lens holder comprises a first connection structure (11), an expansion structure (13) and a base (12), which are sequentially connected in the axial direction of the lens holder; the first connection structure (11) is used for mounting a lens (2); the base (12) is used for mounting an image sensor (3); the expansion structure (13) linearly expands in the axial direction of the lens holder when the temperature rises, so that the distance between the first connection structure (11) and the base (12) is increased.

Description

Lens bracket, lens assembly, camera module, video perspective device and head-mounted display device

[0001] This application claims priority to Chinese patent application No. 202410256887.4, filed on March 6, 2024, entitled “Lens holder, lens assembly, camera module, video perspective device and head-mounted display device”. The entire contents of that application are incorporated herein by reference. Technical Field

[0002] The present application relates to the technical field of head-mounted display devices, and in particular to a lens bracket, a lens assembly, a camera module, a video perspective device, and a head-mounted display device. Background Art

[0003] Virtual reality (VR) and mixed reality (MR) glasses are increasingly focusing on VST (video seethrough) or passthrough functionality. This functionality has evolved from simply setting a safe zone in its early stages to meeting the human eye's perception and achieving MR requirements for a seamless fusion of real scenes and virtual objects. Summary of the Invention

[0004] In order to solve the above technical problems, the present application provides a lens holder, a lens assembly, a camera module, a video perspective device and a head-mounted display device.

[0005] In a first aspect, the present application provides a lens holder, comprising a first connecting structure, an expansion structure, and a base connected in sequence along the axial direction of the lens holder, wherein the first connecting structure is used to mount the lens, and the base is used to mount the image sensor. When the temperature rises, the expansion structure expands linearly along the axial direction of the lens holder to increase the distance between the first connecting structure and the base.

[0006] Optionally, the expansion structure is made of polyester or nylon.

[0007] In a second aspect, the present application provides a lens assembly, comprising a lens and the lens holder as described above; the lens is provided with a second connecting structure connected to the first connecting structure.

[0008] Optionally, the first connecting structure includes a buckle with a set arc extending along the circumference of the lens holder, and the first buckle end face of the buckle in the axial direction of the lens holder is used to limit the axial position with the first clamping end face on the second connecting structure, and the first buckle end face is arranged opposite to the base.

[0009] Optionally, a second snap-on end face of the snap-on is arranged opposite to the first snap-on end face in the axial direction of the lens holder and is used to limit the axial position with a second snap-on end face on the lens, and a slot for snapping with the snap-on is formed between the second snap-on end face and the first snap-on end face.

[0010] Optionally, a buckle limiting end is provided at one end of the buckle, and a lens assembly limiting end is provided at one end of the slot, and the buckle limiting end and the lens assembly limiting end cooperate in the circumferential limit direction of the lens bracket.

[0011] Optionally, a plurality of the buckles and the slots are arranged at intervals along the circumference of the lens holder, and an escape space is formed between each two adjacent buckles for the slots to pass through in the axial direction of the lens holder.

[0012] Optionally, the second clamping end surface is a sloped structure, wherein a side of the second clamping end surface away from the limiting end of the lens assembly forms an opening with the first clamping end surface, and gradually approaches the first clamping end surface toward the limiting end of the lens assembly;

[0013] And / or the second buckle end surface is a slope structure, and the second buckle end surface gradually moves away from the first buckle end surface in a direction away from the buckle limiting end.

[0014] Optionally, the lens includes multiple resin lenses.

[0015] Optionally, the first lens of the lens is a convex mirror, and the optical power of the white lens of the lens matches the temperature drift of the refractive index.

[0016] In a third aspect, the present application provides a camera module, comprising an image sensor, a control board, and the lens assembly as described above;

[0017] The image sensor and the control board are both mounted on the base; the image sensor and the lens are both electrically connected to the control board.

[0018] Optionally, the control board is a flexible circuit board.

[0019] Optionally, the control board is mounted on the lens bracket, and the image sensor is mounted on the control board.

[0020] Optionally, the camera module further includes a temperature sensor, which is electrically connected to the control board and is mounted on the control board or the lens bracket.

[0021] In a fourth aspect, the present application provides a video perspective device comprising the camera module as described above.

[0022] In a fifth aspect, the present application provides a head-mounted display device, comprising the video see-through device as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0024] In order to more clearly illustrate the embodiments of the present application 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, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] FIG1 is a cross-sectional view of a camera module according to an embodiment of the present application;

[0026] FIG2 is a schematic structural diagram of a lens according to an embodiment of the present application when it is installed on a lens holder;

[0027] FIG3 is a schematic structural diagram of a lens according to an embodiment of the present application;

[0028] FIG4 is a schematic structural diagram of a lens holder according to an embodiment of the present application;

[0029] FIG5 is a schematic structural diagram of the camera module according to an embodiment of the present application.

[0030] Among them, 11, first connecting structure; 111, buckle; 1111, first buckle end face; 1112, second buckle end face; 1113, buckle limiting end; 12, base; 13, expansion structure;

[0031] 2. Lens; 21. Second connecting structure; 211. First clamping end surface; 212. Second clamping end surface; 213. Lens assembly limiting end;

[0032] 3. Image sensor;

[0033] 4. Control panel;

[0034] 5. Temperature sensor. DETAILED DESCRIPTION

[0035] In order to more clearly understand the above-mentioned objectives, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0036] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application can also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present application, not all of the embodiments.

[0037] As mentioned above, virtual reality and mixed reality goggles are increasingly emphasizing VST (visualization / transmission) or passthrough functionality. The camera modules used to implement VST have evolved from low-resolution, multiplexed 6D0F cameras to color cameras. To achieve even clearer and more realistic images, the resolution of color cameras is gradually increasing. Furthermore, to achieve low latency and smooth playback, frame rates above 60 fps are often used, significantly increasing power consumption and load, leading to significantly increased camera heat generation. Furthermore, to improve wearing comfort, the overall weight and size of the device have been reduced, further compromising the thermal environment in which the camera operates. Thermally-induced changes in camera performance have become a pressing issue that needs to be addressed.

[0038] At present, the temperature increase of the lens assembly mainly causes the back focal length (BFL) of the lens assembly to become longer, causing the best clear imaging position to shift, resulting in unclear imaging and affecting the user's actual usage experience.

[0039] As shown in Figures 1 to 5, a lens holder provided in this embodiment includes a first connecting structure 11, an expansion structure 13 and a base 12 connected in sequence along the axial direction of the lens holder. The first connecting structure 11 is used to install the lens 2, and the base 12 is used to install the image sensor 3. The expansion structure 13 expands linearly along the axial direction of the lens holder when the temperature rises, so that the distance between the first connecting structure 11 and the base 12 increases.

[0040] It can be understood that a linear expansion area is formed between the first connecting structure 11 and the base 12 by the expansion structure 13 that can expand linearly along the axial direction of the lens holder when the temperature rises. After the lens assembly is heated, the linear expansion characteristic of the expansion structure 13 can be utilized to expand a set distance at the corresponding temperature, thereby changing the distance between the lens 2 and the image sensor 3, thereby achieving the purpose of changing the back focal length (BFL), thereby compensating for the lengthening of the back focal length (BFL) of the lens 2 itself due to the influence of temperature rise, enabling the image sensor 3 to obtain a clear image, and reducing the impact of temperature rise on the lens 2 using the lens holder.

[0041] In some embodiments, the material of the expansion structure 13 is polyester material (PBT) or nylon material (PA); when these two materials are used, the linear expansion coefficient of the expansion structure 13 is nearly doubled compared to the linear expansion coefficient of traditional NTB932 series materials, LCP materials and PC series materials. The thermal deformation height H of the expansion structure 13 used in conjunction with the lens holder in the present application is higher than the thermal deformation height H of the traditional lens holder, thereby being able to achieve a larger bracket thermal compensation height when the temperature changes quantitatively, to ensure that the camera module takes pictures with continuous clarity at different temperatures; specifically, the bracket thermal compensation height = linear expansion coefficient * thermal deformation height H * temperature change range.

[0042] Furthermore, the first connection structure 11, the expansion structure 13 and the base 12 can be integrally formed or can be separate structures, as long as the expansion structure 13 can have a certain height in the axial direction of the lens holder for linear expansion.

[0043] In a second aspect, the present application provides a lens assembly, comprising a lens 2 and the lens holder as described above; the lens 2 is provided with a second connecting structure 21 connected to the first connecting structure 11 .

[0044] Exemplarily, in a specific implementation, referring to Figures 2 and 4, the first connecting structure 11 includes a buckle 111 with a set arc extending along the circumference of the lens holder, and the first buckle end face 1111 of the buckle 111 in the axial direction of the lens holder is used to limit the axial position with the first clamping end face 211 on the second connecting structure 21, and the first buckle end face 1111 is arranged back to back with the base 12. Specifically, the thermal deformation height H of the lens holder refers to the height of the expansion structure 13, that is, the distance between the first buckle end face 1111 and the base 12.

[0045] It should be noted that the first snap-fit ​​end face 1111 supports the first snap-fit ​​end face 211 in the axial direction of the lens holder, so that when the expansion structure 13 undergoes linear expansion, the first snap-fit ​​end face 1111 generates a thrust on the first snap-fit ​​end face 211, thereby moving the lens 2 toward the side away from the image sensor 3, thereby lengthening the back focal length (BFL).

[0046] Furthermore, the second snap-on end face 1112 of the snap-on 111 is arranged opposite to the first snap-on end face 1111 in the axial direction of the lens holder and is used to limit the axial position of the second snap-on end face 212 on the lens 2, and a slot is formed between the second snap-on end face 212 and the first snap-on end face 211 to engage with the snap-on 111.

[0047] It should be understood that the buckle 111 is a structure formed by the inner wall of the lens holder protruding radially inward, and a first buckle end face 1111 and a second buckle end face 1112 are formed in the axial direction of the lens holder respectively; the lens 2 first moves a certain distance toward the lens holder, and then the buckle 111 is inserted into the lens 2 by rotating the lens 2, and the axial locking of the lens holder and the lens 2 can be achieved through the first buckle end face 1111 and the second buckle end face 1112, and the locking of the slot and the buckle 111 can be achieved. When the lens 2 is rotated in the opposite direction, the slot and the buckle 111 can be unlocked; in other embodiments, the lens 2 can also be made into an integral structure with the lens holder, and the buckle 111 can be used to push the lens 2 during thermal expansion to complete focal length compensation.

[0048] In some embodiments, a buckle limit end 1113 is provided at one end of the buckle 111, and a lens assembly limit end 213 is provided at one end of the slot, and the buckle limit end 1113 and the lens assembly limit end 213 cooperate in the circumferential limit of the lens bracket; further, the buckle limit end 1113 and the lens assembly limit end 213 are both planes passing through the axis of the lens bracket, so that the lens bracket and the lens 2 form a stable limiting effect in the circumferential direction, ensuring that the lens 2 and the lens bracket are installed in place, and at the same time, it can also improve the connection stability and reliability between the lens 2 and the lens bracket.

[0049] Furthermore, there are multiple buckles 111 and slots arranged at intervals along the circumference of the lens holder, and an escape space is formed between each two adjacent buckles 111 for the slot to pass through in the axial direction of the lens holder; through the arrangement of multiple buckles 111, the connection points with the lens 2 can be increased, and the connection stability of the lens 2 and the lens holder can be improved. At the same time, the escape space formed between two adjacent buckles 111 can prevent the slot on the lens 2 from being interfered with by the lens holder before it is inserted into place. When the buckle 111 is opposite to the corresponding slot on the lens 2, the lens 2 is rotated to complete the action of inserting the buckle 111 into the slot; referring to Figures 1 to 4, there are two buckles 111, and the two buckles 111 are set 180 degrees apart.

[0050] For example, referring to Figures 2 to 4, the second clamping end face 212 is a slope structure, and the side of the second clamping end face 212 away from the lens assembly limiting end 213 forms an opening with the first clamping end face 211, and gradually approaches the first clamping end face 211 in the direction of the lens assembly limiting end 213; and / or the second buckle end face 1112 is a slope structure, and the second buckle end face 1112 gradually moves away from the first buckle end face 1111 in the direction away from the buckle limiting end 1113, thereby forming a tip structure that is easy to insert into the slot; it should be understood that such a setting can reduce the connection between the second connecting structure 21 and the buckle 111 Difficulty, the second snap-fit ​​end face 212 and / or the second snap-fit ​​end face 1112 can form a guiding structure, and the opening formed by the first snap-fit ​​end face 211 and the second snap-fit ​​end face 212 can be used to better align the snap-fit ​​111, and the connection between the snap-fit ​​111 and the second connecting structure 21 can be completed quickly and accurately, and the tip structure formed by the first snap-fit ​​end face 1111 and the second snap-fit ​​end face 1112 can be used to better align the card slot, and the connection between the snap-fit ​​111 and the second connecting structure 21 can be completed quickly and accurately; the first snap-fit ​​end face 211 and the first snap-fit ​​end face 1111 are both located on a plane perpendicular to the axis of the lens holder, which can more smoothly complete the position adjustment of the lens 2.

[0051] It is understandable that the first connecting structure 11 can also be directly connected to the second connecting structure 21 by bolt connection, welding, bonding, etc., as long as the first connecting structure 11 can generate a thrust on the second connecting structure 21 away from the image sensor 3 when the expansion structure 13 undergoes linear expansion, and the lens 2 is moved away from the image sensor 3.

[0052] In some embodiments, the lens 2 includes multiple resin lenses, which can be a 5P lens assembly, a 6P lens assembly, or a 7P lens assembly, so as to ensure that the camera module using the lens 2 has clearer imaging.

[0053] Furthermore, the first lens of lens 2 is a convex mirror, and the optical focal length and refractive index temperature drift of the white lens of lens 2 are matched; by adjusting the surface shape of the first lens assembly, the optical focal length of each lens in the lens assembly and the refractive index ratio of the refractive index as the temperature changes, the effect of temperature on the effective focal length (EFL) and back focal length (BFL) of the lens assembly can be weakened. The lens 2 is designed under the actual working temperature rather than the design under the normal temperature production state, which further ensures the optimal overall performance under the working conditions; specifically, the temperature of the lens 2 in actual design and use conditions is around 40-50°C, and the actual distance of AA (active attachment) during production is determined, so that the camera module suitable for high temperature conditions can be produced at room temperature. During the design, the height of the expansion structure 13 and the internal parameters of the lens 2 can be timely corrected and adjusted, thereby further reducing the impact of temperature increase on the imaging clarity of the camera module.

[0054] Compared with the high-resolution RGB module of the traditional 6P lens assembly, when the temperature of the lens assembly rises from 25°C to 40-50°C, the SFR value at 1 / 4 Nyquist frequency in the central area will change by 18-20 points; the result of the design of the camera module of the present application is that there is no change in the SFR value, that is, the clarity does not change, and the SFR value of the production result also changes within 5 points.

[0055] By using a linear expansion lens holder, when the back focal length of the lens 2 increases due to temperature rise, the linear expansion lens holder can be used to drive the lens 2 to move toward the side away from the image sensor 3, thereby compensating for the lengthened back focal length.

[0056] On the third aspect, the present application provides a camera module, including an image sensor 3, a control board 4 and the lens assembly as described above; the image sensor 3 and the control board 4 are both mounted on a base 12; the image sensor 3 and the lens 2 are both electrically connected to the control board 4; wherein the image sensor 3 can be a CMOS (Complementary Metal Oxide Semiconductor) or a CCD (Charge-Coupled Device).

[0057] In some embodiments, the control board 4 is selected to be a flexible printed circuit (FPC), and the control board 4 can also be selected to be a printed circuit board (PCB).

[0058] For example, in a specific implementation, referring to FIG. 1 , the control board 4 is mounted on the lens holder, and the image sensor 3 is mounted on the control board 4 .

[0059] Specifically, the camera module also includes a temperature sensor 5, which is electrically connected to the control board 4 and is installed on the control board 4 or the lens bracket; wherein, the temperature sensor 5 is used to timely feedback the temperature of the camera module. Through design and testing, the relationship between the change in temperature and the effective focal length (EFL) of the camera module can be determined, thereby determining the relationship between the change in the intrinsic reference focal length (Focal Length) of the lens 2 with the temperature. Then, the algorithm is used to calculate how to adjust the intrinsic reference focal length (Focal Length) of the lens 2 under the real-time temperature feedback from the temperature sensor 5, and further fine-tune the compensation for the linear expansion area to achieve continuous clear imaging; compared with traditional camera modules, when the temperature of the lens assembly rises from 25°C to 40-50°C, the reprojection error is generally more than 2 pixels. After the linear expansion of the lens bracket of this application and the compensation for the intrinsic reference focal length (Focal Length) of the lens 2, the target can be reduced by an order of magnitude.

[0060] By using a linear expansion lens holder that can compensate for the increase in the back focal length (BFL) of the lens 2 itself due to the influence of temperature increase, the image sensor 3 can obtain a clear image, reduce the impact of temperature increase on the lens 2 using the lens holder, improve the reliability and stability of the entire camera module, and reduce the impact of temperature increase of the lens assembly on the entire camera module.

[0061] In a fourth aspect, the present application provides a video perspective device comprising the camera module as described above.

[0062] By using the above-mentioned camera module, the reprojection error caused by the heating of the lens assembly can be reduced when the temperature rise occurs, and blur or abnormal depth position in the video perspective device experience can be effectively avoided.

[0063] In a fifth aspect, the present application provides a head-mounted display device, comprising the video see-through device as described above.

[0064] After using the above-mentioned camera module in the video see-through device of the head-mounted display device, it is possible to reduce the reprojection error caused by the temperature rise of the lens assembly. The error of more than 2 pixels generated by the traditional camera module when the lens assembly temperature rises from 25°C to 40-50°C is reduced by an order of magnitude, effectively avoiding the blurring or abnormal depth position experience of the video see-through device, thereby significantly improving the user experience.

[0065] The specific implementation method and implementation principle are the same as those in the above embodiment, and can bring the same or similar technical effects, which will not be described here one by one. For details, please refer to the description of the above lens bracket embodiment.

[0066] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0067] The foregoing description is intended only to provide specific embodiments of the present application, which will enable those skilled in the art to understand and implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments described herein, but is intended to be construed in the broadest manner consistent with the principles and novel features disclosed herein.

Claims

1. A lens holder, wherein: The invention comprises a first connection structure (11), an expansion structure (13) and a base (12) which are sequentially connected along the axial direction of the lens holder, wherein the first connection structure (11) is used for mounting a lens (2), the base (12) is used for mounting an image sensor (3), and the expansion structure (13) linearly expands along the axial direction of the lens holder when the temperature rises, so that the distance between the first connection structure (11) and the base (12) increases.

2. The lens holder according to claim 1, wherein: The expansion structure (13) is made of polyester or nylon.

3. A lens assembly, wherein: Comprising a lens (2) and a lens holder as claimed in claim 1 or 2; The lens (2) is provided with a second connecting structure (21) connected to the first connecting structure (11).

4. The lens assembly according to claim 3, wherein: The first connecting structure (11) comprises a buckle (111) extending along the circumference of the lens holder to a set arc, a first buckle end face (1111) of the buckle (111) in the axial direction of the lens holder being used for axially limiting with a first clamping end face (211) on the second connecting structure (21), and the first buckle end face (1111) is arranged opposite to the base (12).

5. The lens assembly according to claim 4, wherein: The second snap-in end face (1112) of the snap-in (111) is arranged opposite to the first snap-in end face (1111) in the axial direction of the lens holder and is used for axially limiting the position of the second snap-in end face (212) on the lens (2); a snap-in groove for snapping with the snap-in (111) is formed between the second snap-in end face (212) and the first snap-in end face (211).

6. The lens assembly according to claim 5, wherein: One end of the buckle (111) is provided with a buckle limiting end (1113), and one end of the slot is provided with a lens assembly limiting end (213), and the buckle limiting end (1113) and the lens assembly limiting end (213) cooperate in a circumferential upper limit direction of the lens bracket.

7. The lens assembly according to claim 5, wherein: A plurality of the buckles (111) and the slots are arranged at intervals along the circumference of the lens holder, and an escape space is formed between each two adjacent buckles (111) for the slots to pass through in the axial direction of the lens holder.

8. The lens assembly according to claim 6, wherein: The second clamping end surface (212) is a slope structure, and a side of the second clamping end surface (212) away from the lens assembly limiting end (213) forms an opening with the first clamping end surface (211), and gradually approaches the first clamping end surface (211) toward the lens assembly limiting end (213); And / or the second buckle end surface (1112) is a slope structure, and the second buckle end surface (1112) gradually moves away from the first buckle end surface (1111) in a direction away from the buckle limiting end (1113).

9. The lens assembly according to claim 3, wherein: The lens (2) comprises a plurality of resin lenses.

10. The lens assembly according to claim 9, wherein: The first lens of the lens (2) is a convex mirror, and the optical power of the white lens of the lens (2) matches the temperature drift change of the refractive index.

11. A camera module, wherein: comprising an image sensor (3), a control board (4) and a lens assembly as claimed in any one of claims 3 to 10; The image sensor (3) and the control board (4) are both mounted on the base (12); the image sensor (3) and the lens (2) are both electrically connected to the control board (4).

12. The camera module according to claim 11, wherein: The control board (4) is a flexible circuit board.

13. The camera module according to claim 11, wherein: The control board (4) is mounted on the lens bracket, and the image sensor (3) is mounted on the control board (4).

14. The camera module according to any one of claims 11 to 13, wherein: The camera module further comprises a temperature sensor (5), the temperature sensor (5) being electrically connected to the control board (4), and the temperature sensor (5) being mounted on the control board (4) or the lens bracket.

15. A video see-through device for a head-mounted display device, wherein: Comprising the camera module according to any one of claims 11 to 14.

16. A head-mounted display device, wherein: Comprising the video see-through device as claimed in claim 15.

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