A new prism that enables large-field-of-view high-resolution sampling and small-field-of-view imaging systems

Abstract

The present invention discloses a prism module for achieving high-resolution sampling of incident light with a large field of view. The prism module includes a plurality of elongated prisms arranged around a central axis, each prism including a front surface; a rear surface; and a reflective surface connected to the front surface on a first edge and to the rear surface on a second edge, wherein the front surface is configured to receive incident light arranged orthogonally relative to the front surface, and the reflective surface is configured to reflect the incident light so that the outgoing light exits through the rear surface at a right angle to form an image with maximum distortion that is unrecognizable to the naked eye.

Description

Technical Field

[0001] The present invention relates to a small imaging system suitable for high-resolution sampling with a large field of view (FOV). Specifically, the present invention relates to a prism module suitable for high-resolution sampling with a large field of view (FOV). Background Art

[0002] Conventional optical systems used to guide incident beams with large fields of view (FOVs) in wearable eyewear, such as augmented reality / virtual reality / mixed reality (AR / VR / MR) glasses, typically occupy a large area. Because each pair of glasses requires at least two light sources to be tested, arranged within a space further defined by a pair of frames, the available space for optical, functional, and quality testing of fully assembled or assembled glasses is even more limited. Furthermore, given that the incident beam to be tested or measured may form an acute angle with the optical axis of the human pupil, the large FOV requires that the optical system used to test such glasses be capable of directing the incident beam at an acute angle to an imaging plane where the resulting image is collected and analyzed. Existing solutions, such as those involving optical systems and components using mirrors, are bulky and occupy a significant amount of space. In some cases, the temples of AR / VR / MR glasses, particularly those sized for children, may need to be removed, increasing testing costs and impacting manufacturing quality due to the potential for additional assembly steps and the potential for errors introduced at each step. Sampling the large FOV beam requires a smaller FOV imaging system. Summary of the Invention

[0003] Objectives of the invention: One objective of the present invention is to provide an optical element or system capable of sampling a large field of view (FOV) beam on a smaller FOV imaging system. Another objective of the present invention is to provide an optical element or system capable of sampling a large field of view (FOV) beam on a smaller FOV imaging system from wearable augmented reality / virtual reality / mixed reality goggles.

[0004] Technical solution: The present invention relates to a prism module capable of performing high-resolution sampling of incident light with a large field of view. The prism module comprises a plurality of elongated prisms arranged around a central axis, each prism comprising: a front surface; a rear surface; and a reflective surface connected to the front surface on a first edge and to the rear surface on a second edge, wherein the front surface is configured to receive incident light arranged orthogonally relative to the front surface, and the reflective surface is configured to reflect the incident light so that the outgoing light is emitted through the rear surface at a right angle, thereby forming an image with maximum distortion that is unrecognizable to the human eye.

[0005] In one embodiment, the maximum distortion is approximately 2%.

[0006] In one embodiment, the incident light is light from a collimated light source, a converging light source, or a diverging light source.

[0007] In one embodiment, at least one of the plurality of elongated prisms comprises two triangular prisms.

[0008] In one embodiment, at least one of the plurality of elongated prisms is arranged at an angle of 0 degrees, 16 degrees, 23 degrees, or 28 degrees relative to the central axis.

[0009] Advantageous Effects: The optical element of the prism module of the present invention is capable of sampling a large field of view (FOV) beam on a smaller FOV imaging system, while having a compact form factor, thereby enabling it to be used in limited spaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram illustrating sampling a large field of view (FO) beam from a pair of virtual reality (VR) glasses using a pair of prism modules on a smaller FOV imaging system;

[0011] Figure 2 is a schematic diagram depicting a front view of a prism module for sampling a large field of view (FOV) beam on a smaller FOV imaging system;

[0012] Figure 3 is a schematic diagram depicting a side view of a prism module for sampling a large field of view (FOV) beam on a smaller FOV imaging system;

[0013] Figure 4 is the front view of the prism module;

[0014] Figure 5 is a side view of a prism of the prism module;

[0015] Figure 5A The beam is Figure 5 A footprint diagram of a front surface of a prism of a prism module;

[0016] Figure 5B The beam is Figure 5A Footprint of the rear surface of the same prism;

[0017] Figure 6 is a side view of a prism and its components;

[0018] Figure 7 is a schematic diagram depicting angles of incident light beams for various prisms of the prism module;

[0019] Figure 8 is a footprint diagram showing the test results of the Prism module;

[0020] Figure 9Depicts using a prism module to direct a converging light beam, for example, for a light input disposed at a +0.65 virtual imaging distance (VID); in one embodiment, a back focal length (BFL) of approximately 92.93 mm;

[0021] Figure 10 Depicts the use of a prism module to direct a light beam disposed at an infinite VID; in one embodiment, the back focal length (BFL) is approximately 87.37 mm;

[0022] Figure 11 Depicts the use of a prism module to direct a diverging light beam, for example, for an optical input arranged at a -0.65D VID; in one embodiment, the back focal length (BFL) is approximately 81.16 mm;

[0023] Figure 12 is a side view depicting a prism for directing a light beam arranged at approximately 28 degrees from a central axis of the prism module;

[0024] Figure 13 Depicted as Figure 12 Dot plot of test results on the prism shown;

[0025] Figure 14 As Figure 12 Schematic diagram of the polychromatic diffraction modulation transfer function (MTF) of the test results on the prism shown;

[0026] Figure 15 is Figure 12 Distortion diagram obtained from the test results on the prism shown;

[0027] Figure 16 is a side view depicting a prism for directing a light beam disposed approximately 23 degrees relative to a central axis of the prism module;

[0028] Figure 17 Depicted as Figure 16 Dot plot of test results on the prism shown;

[0029] Figure 18 Depicted as Figure 16 The multi-color diffraction MTF diagram of the test results on the prism shown;

[0030] Figure 19 is Figure 16 Distortion diagram obtained from the test results on the prism shown;

[0031] Figure 20 is a side view depicting a prism for directing a light beam disposed at an angle of approximately 23 degrees about a central axis of the prism module;

[0032] Figure 21 Depicted as Figure 20 Dot plot of test results on the prism shown;

[0033] Figure 22 As Figure 20 Multi-color diffraction MTF diagram of the test results on the prism shown;

[0034] Figure 23 is Figure 20 Distortion diagram obtained from the test results on the prism shown;

[0035] Among them, prism module 2; prism or elongated prism 4, front surface 6; back surface 8; reflective surface 10; right angle 12; light 14; light source 16; augmented reality / virtual reality / mixed reality (AR / VR / MR) glasses 18; augmented reality / virtual reality / mixed reality glasses temple line 20; image plane 22; imaging lens 24; half the distance between the temples or spatial limit 26; temple length 28; gap 30; distance between the light source and prism module 32; central axis of the prism 34; diffraction limit circle 36; point arrangement 38; angle 40; central axis of the prism module 42; triangular prism 44; bottom surface of the triangular prism 46; top surface of the triangular prism 48; footprint map 50 generated based on the results collected from the image plane. DETAILED DESCRIPTION

[0036] As used herein, the term "approximately" means approximately, roughly, about, or within the range of. When the term "approximately" is used in conjunction with a numerical range, it modifies that numerical range by extending the boundaries above and below the stated values. Generally, as used herein, the term "approximately" modifies the stated value by a variance of 20% above or below the stated value.

[0037] Figure 1 It is a schematic diagram describing the use of a pair of prism modules 2 on a smaller FOV imaging system to sample a large field of view (FOV) light beam from a light source 16 of a pair of augmented reality / virtual reality / mixed reality (AR / VR / MR) glasses 18, wherein the imaging system is specifically embodied as an imaging system having an imaging plane 22. Figure 1A pair of glasses is shown with a light source 16, all of which are flanked by a pair of temples 20. When assembled, the glasses 18 are prepared for testing, for example for quality control purposes. Since the temples 20 are an integral part of the glasses 18, any testing and measurement of the glasses is performed or obtained without disassembling the temples 20 for access, both from an optical (when arranged on the wearer's face) and control perspective. In one example, the gap provided for the test equipment is half the width between the pair of temples 20, as two test devices are required for the wearer's eyes. In one example, at the longitudinal position of the temples where the test equipment is set, the temple-to-tem gap is approximately 130 mm. Therefore, the width of the space provided for the test equipment is only half the temple-to-tem gap or approximately 65 mm. The present prism module 2 is configured to be arranged in this space. The prism module 2 is capable of large field of view high resolution sampling of incident light, such as Figure 1 and other figures elsewhere in this article. Figure 2 is a diagram depicting a lower elevation view of a prism module 2 for sampling a large field of view (FOV) beam on a smaller FOV imaging system, which is shown as an imaging system having an imaging plane 22. Figure 3 is a diagram depicting a side view of a prism module 2 for sampling a large field of view (FOV) beam on a smaller FOV imaging system, which is shown as an imaging system having an imaging plane 22.

[0038] Figure 4 4 is a front perspective view of the prism module 2. The prism module 2 includes a plurality of elongated prisms 4 arranged about a central axis 42. In this embodiment, the prism module 2 includes eight prisms, although the prism module 2 can be configured to have more or fewer prisms as desired. Each prism 4 includes a front surface 6, a rear surface 8, and a reflective surface 10, which is connected to the front surface 6 at a first edge and to the rear surface 8 at a second edge. The front surface 6 is configured to receive an incident light ray arranged orthogonally relative to the front surface 6, and the reflective surface 10 is configured to reflect the incident light ray so that the outgoing light ray exits through the rear surface 8 at a right angle 12, thereby forming an image with maximum distortion that is not recognizable to the human eye. As shown in FIG. Figure 1 As shown, to minimize the FOV, the light source 16 is transmitted through the prism module 2 to the light 14 , and the footprint of the light 14 is suitable for the imaging lens 24 disposed between the prism module 2 and the image plane 22 .

[0039] Figure 5 is a side view of prism 4 of prism module 2 , for example, as would result when prism module 2 is cut along line KK to produce a cross-sectional view of prism B. Light beam 14 is shown disposed through prism 4 . Figure 5A yes Figure 5Footprint of the light beam 14 at the front surface 6 of the prism of the prism module. Figure 5B is the beam 14 in Figure 5A Footprint of the rear surface 8 of the same prism. In one example, the height of the front surface 6 is about 8 mm, the length of the reflective surface 10 is about 35 mm, and the height of the rear surface 8 is about 15 mm. Back Figure 1 In one example, the length 28 of the temple 20 is approximately 173 mm, and care must be taken to ensure that the optical path passes through the entire length of the temple 20 when the temple 20 is in the upright position. Here, a gap 30 of approximately 3 mm is provided for the imaging lens 24 in a direction transverse to the optical path of the imaging lens 24. In one embodiment, the distance 32 between the light source 16 and the prism module 2 is approximately 17 mm.

[0040] Figure 6 is a side view of a prism and its components. In one embodiment, prism 4 can be composed of two triangular prisms 44, as shown on the left side of the figure. Top triangular prism 44 is combined with bottom triangular prism 44 so that bottom surface 46 of top triangular prism 44 mates with top surface 48 of bottom triangular prism 44, thereby forming prism 4 on the right side of the figure.

[0041] Figure 7 is a diagram depicting the angles of incident light beams for various prisms 4 of the prism module 2. The applicant has discovered that by arranging the prisms 4 at a specific angle 40 to the central axis of the prism module 2, the resulting light beams can be formed on the image plane 22 in a compact manner, thereby reducing the amount of blank and unused areas on the image plane 22. Figure 4 、 7 8, it should be noted that, in one embodiment, the prisms 4 of the prism module 2 are arranged at different angles relative to the central axis 42 of the prism module 2. Here, the incident light rays are aligned orthogonally with the front surface 6 of the prism 4 at angles of 16 degrees, 23 degrees, and 28 degrees relative to the central axis 42 of the prism module 2. The centrally positioned prism E is referred to as being arranged at 0 degrees relative to the central axis 42 of the prism module 2 because the central axis 42 passes through the prism module 2 and is positioned at the center. Prisms A, C, and G are arranged at 23 degrees relative to the central axis 42. Prisms B and H are arranged at 28 degrees relative to the central axis 42. Prisms D and F are arranged at 16 degrees relative to the central axis 42.

[0042] Figure 8 is a footprint plot 50 showing the test results on the prism module 2. Note the compactness of the spot map 38 generated based on the results collected from the image plane 22.

[0043] Figure 9 Depicted is the use of a prism module to direct a converging light beam, for example, for a light input disposed at a +0.65 virtual imaging distance (VID).In one embodiment, the back focal length (BFL) is approximately 92.93 mm. Figure 10 Depicted is the use of a prism module to direct a light beam disposed at infinity.In one embodiment, the back focal length (BFL) is approximately 87.37 mm. Figure 11 The use of a prism module for directing a diverging light beam is depicted, for example, for a light input set at a -0.65D VID. In one embodiment, the back focal length (BFL) is approximately 81.16 mm. Note that Figure 11 In the case of a diverging light beam, the prism module 2 has the ability to transmit a diverging light beam, while it is also suitable for transmitting a converging and collimated light beam, respectively. Figure 9 and Figure 10 situation.

[0044] In ensuring that the prism module 2 is useful for achieving high-resolution sampling of incident light over a large FOV, measurements were taken to ensure that the prism module 2 can produce satisfactory results for each type of incident light, namely, converging, collimated, and diverging beams. Newton's imaging formula. Figure 12-15 represents the set of results obtained for an infinite virtual imaging distance (VID), ie with collimated rays 28 degrees from the central axis 42. Newtonian Imaging Formula. Figure 16-19 = 20-23 represents the result set obtained for an infinite VID, i.e., with collimated light at 23 degrees from the central axis 42. Newton's imaging formula. 20-23 represents the result set obtained for an infinite VID, i.e., with collimated light at 16 degrees from the central axis 42.

[0045] Figure 12 3 is a side view depicting a prism used to direct a light beam disposed at an angle of approximately 28 degrees about the central axis of the prism module. The direction of the light beam can be represented by the central axis 34 of the prism. Figure 13 Depicted as Figure 12 Spot diagram of the test results on the prism shown. Note that the points within each diffraction limit circle 36 are well arranged within the circle, which means that almost no diffraction is detected in the beam incident on the image plane 22. Figure 14 As Figure 12 Schematic diagram of the polychromatic diffraction modulation transfer function (MTF) test results on the prism shown. Figure 15 is Figure 12 Distortion plot obtained from testing on the prism shown. Note that the maximum distortion is approximately 0.95%.

[0046] Figure 16 is a side view depicting a prism used to direct a light beam, the prism being positioned approximately 23 degrees from the horizontal axis. Figure 17 Depicted as Figure 16 Dot plot of test results on the prism shown. Figure 18 Depicted as Figure 16The polychromatic diffraction MTF diagram of the test results on the prism shown. Figure 19 is Figure 16 Distortion plot obtained from testing on the prism shown. Note that the maximum distortion is approximately 1.15%.

[0047] Figure 20 is a side view depicting a prism used to direct a light beam, the prism being positioned approximately 23 degrees from the horizontal axis. Figure 21 Depicted as Figure 20 Dot plot of test results on the prism shown. Figure 22 As Figure 20 Polychromatic diffraction MTF plot of test results on the prism shown. Figure 23 is Figure 20 The distortion diagram obtained from the test results on the prism shown. It should be noted that the maximum distortion is approximately 0.53%. Overall, it can be concluded that the maximum distortion produced by using this prism module is limited to less than 2%, which is distortion that the human eye cannot detect.

Claims

1. A prism module capable of sampling incident light with a large field of view and high resolution, characterized in that: The prism module includes a plurality of elongated prisms arranged around a central axis, each of the prisms including: a front surface; a rear surface; and a reflective surface connected to the front surface on a first edge and to the rear surface on a second edge, wherein the front surface is configured to receive an incident light ray arranged orthogonally relative to the front surface, and the reflective surface is configured to reflect the incident light ray so that the outgoing light ray exits through the rear surface at a right angle, thereby forming an image with maximum distortion that is not recognizable to the naked eye; the incident light ray is aligned orthogonally to the front surface of the prism and is at angles of 16 degrees, 23 degrees, and 28 degrees to the central axis of the prism module; the prism E arranged in the center is referred to as being arranged at 0 degrees relative to the central axis of the prism module, prisms A, C, and G are arranged at 23 degrees to the central axis; prisms B and H are arranged at 28 degrees to the central axis, and prisms D and F are arranged at 16 degrees to the central axis; the prisms are composed of two triangular prisms, the top triangular prism is combined with the bottom triangular prism so that the bottom surface of the top triangular prism is matched with the top surface of the bottom triangular prism.

2. The prism module according to claim 1, wherein: The maximum distortion is within 2%.

3. The prism module according to claim 1, wherein: The incident light is selected from a collimated light source, a converging light source and a diverging light source.

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