Waveguide device and optical device using the same

Abstract

A waveguide device includes at least one light-transmitting substrate, a first image coupling element, a first image coupling element, a second image coupling element, and a second image coupling element. The light-transmitting substrate includes a central region and a peripheral region surrounding the central region. The first image coupling element is located in the peripheral region and is configured to diffract a first light beam into the light-transmitting substrate. The first image coupling element is located in the central region and is configured to diffract the diffracted first light beam propagating in the light-transmitting substrate. The second image coupling element is located in the peripheral region and is configured to diffract a second light beam into the light-transmitting substrate. The second image coupling element is located in the central region and is configured to diffract the diffracted second light beam propagating in the light-transmitting substrate.

Description

[Technical Field]

[0001] This disclosure relates to a waveguide device and an optical device using the same. [Previous Technology]

[0002] Various types of computing devices, entertainment devices, and / or mobile devices can be implemented through see-through or semi-see-through displays, through which users can view their surrounding environment. Such devices, also known as see-through, mixed reality display systems, or augmented reality (AR) systems, allow users to see their surrounding environment through the device's see-through or semi-see-through display, simultaneously viewing virtual object images (such as text, graphics, videos, etc.) generated for display, making them appear as part of and / or superimposed on the surrounding environment. These devices can be implemented as head-mounted display (HMD) glasses or other wearable display devices, but are not limited to these, and typically utilize optical waveguides to replicate images to locations where the device user can perceive the images as virtual images within the augmented reality environment. As this is still an emerging technology, there are certain challenges when using waveguides to display virtual object images to users.

[0003] However, examining existing augmented reality display devices on the market, their core architecture is mostly based on a single image guidance unit, operating in a one-to-one image input and output mode. Such designs often provide only a single and fixed virtual image presentation effect at any given time, making it difficult to adjust key parameters of the virtual image viewed by the user in real time and flexibly, such as position, virtual image distance, and virtual image field of view. In other words, current technology is still insufficient in providing users with diverse and dynamically adjustable virtual image experiences.

[0004] Therefore, providing a waveguide device that can solve the above problems and an optical device using the same is an important issue for the industry. [Summary of the Invention]

[0005] One aspect of this disclosure is to provide a waveguide device and an optical device using the same, which can effectively solve the aforementioned problems.

[0006] According to one embodiment of the present disclosure, a waveguide device includes at least one light-transmitting substrate, a first image coupling element, a first image coupling element, a second image coupling element, and a second image coupling element. The light-transmitting substrate includes a central region and a peripheral region surrounding the central region. The first image coupling element is located in the peripheral region and is configured to diffract a first light beam propagating in the light-transmitting substrate. The first image coupling element is located in the central region and is configured to diffract the diffracted first light beam propagating in the light-transmitting substrate. The second image coupling element is located in the peripheral region and is configured to diffract a second light beam propagating in the light-transmitting substrate. The second image coupling element is located in the central region and is configured to diffract the diffracted second light beam propagating in the light-transmitting substrate.

[0007] In one embodiment of this disclosure, the first image coupling element and the first image coupling element are radially aligned. The second image coupling element and the second image coupling element are radially aligned.

[0008] In one embodiment of this disclosure, the first beam and the second beam have the same wavelength.

[0009] In one embodiment of this disclosure, a first image coupling element is configured to diffract a first diffracted light beam at a first diffraction angle. A second image coupling element is configured to diffract a second diffracted light beam at a second diffraction angle different from the first diffraction angle.

[0010] In one embodiment of this disclosure, the first image coupling element conforms to a first diffraction wave function. The second image coupling element conforms to a second diffraction wave function different from the first diffraction wave function.

[0011] In one embodiment of this disclosure, the first diffraction wave function is the wave function of the first virtual image distance. The second diffraction wave function is the wave function of the second virtual image distance, which is different from the first virtual image distance.

[0012] In one embodiment of this disclosure, the first diffraction wave function is the wave function of the first virtual image field of view. The second diffraction wave function is the wave function of the second virtual image field of view, which is different from the first virtual image field of view.

[0013] In one embodiment of this disclosure, the first image coupling element includes a first diffraction grating. The second image coupling element includes a second diffraction grating. The first diffraction grating and the second diffraction grating intersect each other.

[0014] In one embodiment of this disclosure, the at least one light-transmitting substrate includes a first light-transmitting substrate and a second light-transmitting substrate. A first image coupling element and a first image coupling element are located on the first light-transmitting substrate. A second image coupling element and a second image coupling element are located on the second light-transmitting substrate.

[0015] In one embodiment of this disclosure, the first beam and the second beam have different wavelengths.

[0016] In one embodiment of this disclosure, the first beam and the second beam have the same wavelength.

[0017] In one embodiment of this disclosure, the central region is rotatably connected to the peripheral region.

[0018] According to one embodiment of the present disclosure, an optical device includes a housing, a waveguide device, and a projector. The waveguide device includes at least one light-transmitting substrate, a first image coupling element, a first image coupling element, a second image coupling element, and a second image coupling element. The light-transmitting substrate is rotatably connected to the housing and includes a central region and a peripheral region surrounding the central region. The first image coupling element is located in the peripheral region and is configured to diffract a first light beam propagating in the light-transmitting substrate. The first image coupling element is located in the central region and is configured to diffract the diffracted first light beam propagating in the light-transmitting substrate. The second image coupling element is located in the peripheral region and is configured to diffract a second light beam propagating in the light-transmitting substrate. The second image coupling element is located in the central region and is configured to diffract the diffracted second light beam propagating in the light-transmitting substrate. The projector is disposed on the housing and configured to emit the first light beam and the second light beam toward the peripheral region along an optical path.

[0019] In one embodiment of this disclosure, the first beam and the second beam have the same wavelength.

[0020] In one embodiment of this disclosure, a first image coupling element is configured to diffract a first diffracted light beam at a first diffraction angle. A second image coupling element is configured to diffract a second diffracted light beam at a second diffraction angle different from the first diffraction angle.

[0021] In one embodiment of this disclosure, the first image coupling element conforms to a first diffraction wave function. The second image coupling element conforms to a second diffraction wave function different from the first diffraction wave function.

[0022] In one embodiment of this disclosure, the first diffraction wavefunction is the wavefunction of a first virtual image distance. The second diffraction wavefunction is the wavefunction of a second virtual image distance, which is different from the first virtual image distance.

[0023] In one embodiment of this disclosure, the first diffraction wave function is the wave function of the first virtual image field of view. The second diffraction wave function is the wave function of the second virtual image field of view, which is different from the first virtual image field of view.

[0024] In one embodiment of this disclosure, the first image coupling element includes a first diffraction grating. The second image coupling element includes a second diffraction grating. The first diffraction grating and the second diffraction grating intersect each other.

[0025] In one embodiment of this disclosure, the central region is rotatably connected to the peripheral region.

[0026] Therefore, in the waveguide device and optical device disclosed herein, by disposing a plurality of image coupling elements in the peripheral region of the light-transmitting substrate and correspondingly disposing a plurality of image coupling elements in the central region of the light-transmitting substrate, independent optical guidance and output control of a plurality of beams can be achieved. In this way, the waveguide device and optical device disclosed herein can effectively solve the bottlenecks encountered in the prior art, such as potential limitations in virtual image position, virtual image distance, or virtual image field of view, thereby providing more flexible and diverse virtual image presentation effects.

[0027] The above description is only used to illustrate the problem to be solved by this disclosure, the technical means to solve the problem, and the effects produced, etc. The specific details of this disclosure will be described in detail in the following implementation methods and related figures.

Implementation Method

[0029] Specific embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Wherever possible, the same element symbols in the drawings and description will be used to refer to the same or similar components. However, the specific structural and functional details disclosed herein are for illustrative purposes only and may therefore be implemented in many alternative forms, and should not be construed as being limited to the illustrative embodiments described herein. Therefore, it should be understood that the illustrative embodiments are not intended to be limited to the specific forms disclosed; rather, the illustrative embodiments are intended to cover all modifications, equivalents, and alternatives falling within the scope of this disclosure.

[0030] Please refer to Figure 1. Figure 1 is a schematic diagram illustrating an optical device 100 according to an embodiment of the present disclosure. As shown in Figure 1, in this embodiment, the optical device 100 can be used in an augmented reality device, which may be implemented as, but is not limited to, a pair of glasses or other wearable display devices. Specifically, the optical device 100 includes a housing 110, two waveguide devices 120, and a projector 130. The housing 110 includes two frames 111, temples 112, and connecting members 113. The waveguide devices 120 are rotatably connected to the inner edges of the frames 111. The temples 112 are connected to the edge of one of the waveguide devices 120. The connecting members 113 are connected between the frames 111. The projector 130 is disposed on the side of the temple 112 near one of the waveguide devices 120. The optical device 100 may include another temple 112 (not shown) connected to the edge of the other waveguide device 120. The main function of each waveguide device 120 is to overlay the virtual image generated by the projector 130 onto the real-world scene seen by the user through the waveguide device 120.

[0031] Please refer to Figure 2. Figure 2 is a front view illustrating one of the waveguide devices 120 in Figure 1. As shown in Figures 1 and 2, in this embodiment, the waveguide device 120 includes a light-transmitting substrate 121, a first image coupling element 122a, a first image coupling element 123a, a second image coupling element 122b, a second image coupling element 123b, a third image coupling element 122c, a third image coupling element 123c, a fourth image coupling element 122d, and a fourth image coupling element 123d. The light-transmitting substrate 121 is rotatably connected to the inner edge of the frame 111 of the housing 110. The light-transmitting substrate 121 includes a central region 121a and a peripheral region 121b surrounding the central region 121a. The first image coupling element 122a, the second image coupling element 122b, the third image coupling element 122c, and the fourth image coupling element 122d are located in the peripheral region 121b. The first image coupling element 123a, the second image coupling element 123b, the third image coupling element 123c, and the fourth image coupling element 123d are located in the central region 121a. Specifically, the first image coupling element 122a and the first image coupling element 123a are radially aligned. The second image coupling element 122b and the second image coupling element 123b are radially aligned. The third image coupling element 122c and the third image coupling element 123c are radially aligned. The fourth image coupling element 122d and the fourth image coupling element 123d are radially aligned. That is, the combination of the first image coupling element 122a and the first image coupling element 123a, the combination of the second image coupling element 122b and the second image coupling element 123b, the combination of the third image coupling element 122c and the third image coupling element 123c, and the combination of the fourth image coupling element 122d and the fourth image coupling element 123d are arranged radially.

[0032] As shown in Figure 1 and referring to Figure 2, in this embodiment, the projector 130 is configured to emit light toward the peripheral region 121b along an optical path OP. In this way, when the light-transmitting substrate 121 rotates counterclockwise relative to the frame 111 of the housing 110, the light emitted by the projector 130 is sequentially incident on the first image coupling element 122a, the second image coupling element 122b, the third image coupling element 122c, and the fourth image coupling element 122d.

[0033] In some embodiments, the central region 121a is rotatably connected to the peripheral region 121b. For example, the central region 121a is fixed relative to the frame 111 of the housing 110, while the peripheral region 121b is rotatable between the frame 111 and the central region 121a. In some embodiments, to address the refraction problem at the interface between the central region 121a and the peripheral region 121b, the interface can be filled with a material that matches the refractive index.

[0034] Please refer to Figure 3A. Figure 3A is a partial schematic diagram illustrating the waveguide device 120 in Figure 2. As shown in Figure 3A, in this embodiment, the light-transmitting substrate 121 has opposing first surfaces 121c and second surfaces 121d. A first image coupling element 122a is disposed on the first surface 121c and configured to diffract a first light beam La and propagate through the light-transmitting substrate 121. Specifically, the first light beam La is a parallel light beam. The first light beam La enters the light-transmitting substrate 121 from the second surface 121d and is incident perpendicularly on the first image coupling element 122a disposed on the first surface 121c. On the other hand, a first image coupling element 123a is disposed on the second surface 121d and configured to diffract the diffracted first light beam La propagating in the light-transmitting substrate 121, and convert it into a first output light beam La1. Specifically, the first output light beam La1 exits the light-transmitting substrate 121 from the first surface 121c.

[0035] Please refer to Figure 3B. Figure 3B is another partial schematic diagram illustrating the waveguide device 120 in Figure 2. As shown in Figure 3B, in this embodiment, the second image coupling element 122b is disposed on the first surface 121c and configured to diffract the second light beam Lb and propagate in the light-transmitting substrate 121. Specifically, the second light beam Lb is a parallel light beam. The second light beam Lb enters the light-transmitting substrate 121 from the second surface 121d and is incident perpendicularly on the second image coupling element 122b disposed on the first surface 121c. On the other hand, the second image coupling element 123b is disposed on the second surface 121d and configured to diffract the diffracted second light beam Lb propagating in the light-transmitting substrate 121, and convert it into a second output light beam Lb1. Specifically, the second output light beam Lb1 exits the light-transmitting substrate 121 from the first surface 121c.

[0036] Please refer to Figure 3C. Figure 3C is another partial schematic diagram illustrating the waveguide device 120 in Figure 2. As shown in Figure 3C, in this embodiment, a third image coupling element 122c is disposed on the first surface 121c and configured to diffract a third beam Lc and propagate in the light-transmitting substrate 121. Specifically, the third beam Lc is a parallel beam. The third beam Lc enters the light-transmitting substrate 121 from the second surface 121d and is incident perpendicularly on the third image coupling element 122c disposed on the first surface 121c. On the other hand, a third image coupling element 123c is disposed on the second surface 121d and configured to diffract the diffracted third beam Lc propagating in the light-transmitting substrate 121, and convert it into a third output beam Lc1. Specifically, the third output beam Lc1 exits the light-transmitting substrate 121 from the first surface 121c.

[0037] Please refer to Figure 3D. Figure 3D is another partial schematic diagram illustrating the waveguide device 120 in Figure 2. As shown in Figure 3D, in this embodiment, a fourth image coupling element 122d is disposed on the first surface 121c and configured to diffract a fourth light beam Ld and propagate in the light-transmitting substrate 121. Specifically, the fourth light beam Ld is a parallel light beam. The fourth light beam Ld enters the light-transmitting substrate 121 from the second surface 121d and is incident perpendicularly on the fourth image coupling element 122d disposed on the first surface 121c. On the other hand, a fourth image coupling element 123d is disposed on the second surface 121d and configured to diffract the diffracted fourth light beam Ld propagating in the light-transmitting substrate 121, and convert it into a fourth output light beam Ld1. Specifically, the fourth output light beam Ld1 exits the light-transmitting substrate 121 from the first surface 121c.

[0038] As shown in Figures 3A to 3D, it can be seen that the diffraction angles of the first image coupling element 123a diffracting the first diffracted beam La, the second image coupling element 123b diffracting the second diffracted beam Lb, the third image coupling element 123c diffracting the third diffracted beam Lc, and the fourth image coupling element 123d diffracting the fourth diffracted beam Ld are different from each other. In this way, the first exit angle θa of the first output beam La1 at the first surface 121c, the second exit angle θb of the second output beam Lb1 at the first surface 121c, the third exit angle θc of the third output beam Lc1 at the first surface 121c, and the fourth exit angle θd of the fourth output beam Ld1 at the first surface 121c are different from each other.

[0039] Please refer to Figure 4. Figure 4 is a schematic diagram illustrating different virtual image positions VPa, VPb, VPc, and VPd. As shown in Figures 3A and 4, the virtual image presented by the first output beam La1 corresponds to the virtual image position VPa in Figure 4 as seen by the user's eyes. As shown in Figures 3B and 4, the virtual image presented by the second output beam Lb1 corresponds to the virtual image position VPb in Figure 4 as seen by the user's eyes. As shown in Figures 3C and 4, the virtual image presented by the third output beam Lc1 corresponds to the virtual image position VPc in Figure 4 as seen by the user's eyes. As shown in Figures 3D and 4, the virtual image presented by the fourth output beam Ld1 corresponds to the virtual image position VPd in ​​Figure 4 as seen by the user's eyes.

[0040] Please refer to Figure 5. Figure 5 is a partial schematic diagram illustrating the first image coupling element 122a in Figure 3A. As shown in Figure 5, in this embodiment, the first image coupling element 122a includes at least one holographic grating 122a1. The holographic grating 122a1 is configured to diffract light (i.e., the first beam La) incident on the first image coupling element 122a. The holographic grating 122a1 of the first image coupling element 122a is a reflective holographic grating, but this disclosure is not limited thereto. In some other embodiments, the holographic grating 122a1 of the first image coupling element 122a may be a transmissive holographic grating, and the first image coupling element 122a may be disposed on the second surface 121d of the light-transmitting substrate 121. The holographic grating 122a1 is a volume holographic grating. It is worth noting that light diffracted by a volume holographic grating can propagate based on Bragg's law.

[0041] In some embodiments, the second image coupling element 122b may include at least one holographic grating configured to diffract light incident on the second image coupling element 122b (i.e., the second beam Lb). In some embodiments, the third image coupling element 122c may include at least one holographic grating configured to diffract light incident on the third image coupling element 122c (i.e., the third beam Lc). In some embodiments, the fourth image coupling element 122d may include at least one holographic grating configured to diffract light incident on the fourth image coupling element 122d (i.e., the fourth beam Ld).

[0042] As shown in Figures 3B to 3D, in this embodiment, the holographic gratings of the second image coupling element 122b, the third image coupling element 122c, and the fourth image coupling element 122d are reflective holographic gratings, but this disclosure is not limited thereto. In some other embodiments, the holographic grating of at least one of the second image coupling element 122b, the third image coupling element 122c, and the fourth image coupling element 122d may be a transmissive holographic grating, and at least one of the aforementioned second image coupling element 122b, the third image coupling element 122c, and the fourth image coupling element 122d may be disposed on the second surface 121d of the light-transmitting substrate 121.

[0043] As shown in Figures 3A to 3D, in this embodiment, the first image coupling element 123a may include at least one holographic grating configured to diffract light propagating in the light-transmitting substrate 121 (i.e., the first beam La). The second image coupling element 123b may include at least one holographic grating configured to diffract light propagating in the light-transmitting substrate 121 (i.e., the second beam Lb). The third image coupling element 123c may include at least one holographic grating configured to diffract light propagating in the light-transmitting substrate 121 (i.e., the third beam Lc). The fourth image coupling element 123d may include at least one holographic grating configured to diffract light propagating in the light-transmitting substrate 121 (i.e., the fourth beam Ld). The holographic gratings of the first image coupling element 123a, the second image coupling element 123b, the third image coupling element 123c, and the fourth image coupling element 123d are reflective holographic gratings, but this disclosure is not limited thereto. In some other embodiments, the holographic grating of at least one of the first image coupling element 123a, the second image coupling element 123b, the third image coupling element 123c, and the fourth image coupling element 123d can be a transmissive holographic grating, and at least one of the aforementioned first image coupling element 123a, the second image coupling element 123b, the third image coupling element 123c, and the fourth image coupling element 123d can be disposed on the first surface 121c of the light-transmitting substrate 121.

[0044] In some embodiments, the first beam La, the second beam Lb, the third beam Lc, and the fourth beam Ld emitted by the projector 130 may have the same wavelength, but this disclosure is not limited thereto.

[0045] Please refer to Figure 6. Figure 6 is a schematic diagram illustrating an optical exposure system 900 used to manufacture holographic optical elements. As shown in Figure 6, the optical exposure system 900 includes two mirrors 920c and 920d, two half-wave plates 930a and 930b, a polarizing beam splitter 940, two spatial filters 950a and 950b, two lenses 960a and 960b, and a prism 970. A photosensitive polymer P is attached to one side of the prism 970. The optical exposure system 900 is configured to expose a portion of the photosensitive polymer P from opposite sides using two beams of light with different incident directions. The photosensitive polymer P includes monomers, polymers, a photo-initiator, and a binder. When the photosensitive polymer P is exposed, the photo-initiator receives photons to generate free radicals, causing the monomers to begin polymerization (i.e., photopolymerization). By using an exposure method employing holographic interference fringes, unilluminated monomers (i.e., in dark areas) diffuse into illuminated areas (i.e., in bright areas) and polymerize, resulting in a gradient of polymer concentration that is not uniform. Finally, after fixing, a phase grating containing staggered bright and dark fringes can be formed, and the photosensitive polymer P is transformed into a holographic optical element.

[0046] In some embodiments, at least one of the first image coupling element 122a, the second image coupling element 122b, the third image coupling element 122c, the fourth image coupling element 122d, the first image coupling element 123a, the second image coupling element 123b, the third image coupling element 123c, and the fourth image coupling element 123d can be manufactured by an optical exposure system 900 as shown in Figure 6.

[0047] Please refer to Figure 7. Figure 7 is a partial schematic diagram illustrating a light-transmitting substrate 121' with a first image coupling element 122a' according to another embodiment of the present disclosure. As shown in Figure 7, in this embodiment, the first image coupling element 122a' formed on the surface of the light-transmitting substrate 121' includes a plurality of surface structures 122a1'. The first image coupling element 122a' uses the surface structures 122a1' to form a periodic width structure. The surface structures 122a1' can be manufactured to form a surface relief diffraction grating, and the surface relief diffraction grating can form a holographic grating. In this way, the diffraction characteristics of the holographic grating of the first image coupling element 122a' formed by the surface relief diffraction grating can be the same as or similar to the diffraction characteristics of the holographic grating of the first image coupling element 122a' formed by the volume holographic grating.

[0048] In some embodiments, at least one of the second image coupling element 122b, the third image coupling element 122c, the fourth image coupling element 122d, the first image coupling element 123a, the second image coupling element 123b, the third image coupling element 123c, and the fourth image coupling element 123d may include a plurality of surface structures forming surface relief diffraction gratings, just like the first image coupling element 122a'.

[0049] Please refer to Figure 8. Figure 8 is a partial schematic diagram illustrating a first image coupling element 122a'' according to another embodiment of the present disclosure. As shown in Figure 8, in this embodiment, the first image coupling element 122a'' includes a plurality of liquid crystal molecules 122a1'' disposed between two photoalignment layers 122a2, and the photoalignment layers 122a2 are sandwiched between two light-transmitting substrates 122a3. A voltage can be applied to the photoalignment layers 122a2 to rotate the liquid crystal molecules 122a1'' to form a periodic width structure. In other words, the first image coupling element 122a'' uses the internal liquid crystal molecules 122a1'' to form a periodic width structure, so the outer surface of the light-transmitting substrate 122a3 has no solid structure. The rotating liquid crystal molecules 122a1'' can form a liquid crystal grating, and the liquid crystal grating can form a holographic grating. In this way, the diffraction characteristics of the holographic grating of the first image coupling element 122a'' formed by the liquid crystal grating can be the same as or similar to the diffraction characteristics of the holographic grating of the first image coupling element 122a formed by the volume holographic grating.

[0050] In some embodiments, at least one of the second image coupling element 122b, the third image coupling element 122c, the fourth image coupling element 122d, the first image coupling element 123a, the second image coupling element 123b, the third image coupling element 123c, and the fourth image coupling element 123d may include a liquid crystal grating, just like the first image coupling element 122a''.

[0051] Please refer to Figures 9A to 9D. Figures 9A to 9D are schematic diagrams illustrating different partial portions of a waveguide device 220 according to another embodiment of the present disclosure. As shown in Figures 9A to 9D, in this embodiment, the waveguide device 220 includes a light-transmitting substrate 121, a first image coupling element 222a, a second image coupling element 222b, a third image coupling element 222c, a fourth image coupling element 222d, a first image coupling element 223a, a second image coupling element 223b, a third image coupling element 223c, and a fourth image coupling element 223d. The relative positions of these components of the waveguide device 220 are the same as the relative positions of the components of the waveguide device 120 shown in Figures 2 to 3D. The functions of the first image coupling element 222a, the second image coupling element 222b, the third image coupling element 222c, and the fourth image coupling element 222d are the same as those of the components of the waveguide device 120. The functions of the first image coupling element 223a, the second image coupling element 223b, the third image coupling element 223c, and the fourth image coupling element 223d are similar to those of the components of the waveguide device 120.

[0052] Specifically, the first image coupling element 223a is configured to diffract the first beam La that propagates in the light-transmitting substrate 121 and convert it into a first output beam La2. The second image coupling element 223b is configured to diffract the second beam Lb that propagates in the light-transmitting substrate 121 and convert it into a second output beam Lb2. The third image coupling element 223c is configured to diffract the third beam Lc that propagates in the light-transmitting substrate 121 and convert it into a third output beam Lc2. The fourth image coupling element 223d is configured to diffract the fourth beam Ld that propagates in the light-transmitting substrate 121 and convert it into a fourth output beam Ld2.

[0053] It should be noted that the first image coupling element 223a conforms to the first diffraction wave function, the second image coupling element 223b conforms to the second diffraction wave function, the third image coupling element 223c conforms to the third diffraction wave function, and the fourth image coupling element 223d conforms to the fourth diffraction wave function. The first, second, third, and fourth diffraction wave functions are different from each other. The first, second, third, and fourth diffraction wave functions are wave functions for different virtual image distances.

[0054] Please refer to Figure 10. Figure 10 is a schematic diagram illustrating different virtual image distances. As shown in Figures 9A and 10, the virtual image presented by the first output beam La2 corresponds to the first virtual image distance VSa in Figure 10 as seen by the user's eye along direction D. As shown in Figures 9B and 10, the virtual image presented by the second output beam Lb2 corresponds to the second virtual image distance VSb in Figure 10 as seen by the user's eye along direction D. As shown in Figures 9C and 10, the virtual image presented by the third output beam Lc2 corresponds to the third virtual image distance VSC in Figure 10 as seen by the user's eye along direction D. As shown in Figures 9D and 10, the virtual image presented by the fourth output beam Ld2 corresponds to the fourth virtual image distance VSd in Figure 10 as seen by the user's eye along direction D. For example, the first virtual image of the first diffraction wave function is infinitely far from VSa, the second virtual image of the second diffraction wave function is about 3 meters from VSb, the third virtual image of the third diffraction wave function is about 1 meter from VSC, and the fourth virtual image of the fourth diffraction wave function is about 0.5 meters from VSd, but this disclosure is not limited to these.

[0055] Please refer to Figures 11A to 11D. Figures 11A to 11D are schematic diagrams illustrating different partial portions of a waveguide device 320 according to another embodiment of the present disclosure. As shown in Figures 11A to 11D, in this embodiment, the waveguide device 320 includes a light-transmitting substrate 121, a first image coupling element 322a, a second image coupling element 322b, a third image coupling element 322c, a fourth image coupling element 322d, a first image coupling element 323a, a second image coupling element 323b, a third image coupling element 323c, and a fourth image coupling element 323d. The relative positions of these components of the waveguide device 320 are the same as the relative positions of the components of the waveguide device 120 shown in Figures 2 to 3D. The functions of the first image coupling element 322a, the second image coupling element 322b, the third image coupling element 322c, and the fourth image coupling element 322d are the same as those of the components of the waveguide device 120. The functions of the first image coupling element 323a, the second image coupling element 323b, the third image coupling element 323c, and the fourth image coupling element 323d are similar to those of the components of the waveguide device 120.

[0056] Specifically, the first image coupling element 323a is configured to diffract the first beam La that propagates in the light-transmitting substrate 121 and convert it into a first output beam La3. The second image coupling element 323b is configured to diffract the second beam Lb that propagates in the light-transmitting substrate 121 and convert it into a second output beam Lb3. The third image coupling element 323c is configured to diffract the third beam Lc that propagates in the light-transmitting substrate 121 and convert it into a third output beam Lc3. The fourth image coupling element 323d is configured to diffract the fourth beam Ld that propagates in the light-transmitting substrate 121 and convert it into a fourth output beam Ld3.

[0057] It should be noted that the first image coupling element 323a conforms to the first diffraction wave function, the second image coupling element 323b conforms to the second diffraction wave function, the third image coupling element 323c conforms to the third diffraction wave function, and the fourth image coupling element 323d conforms to the fourth diffraction wave function. The first, second, third, and fourth diffraction wave functions are different from each other. The first, second, third, and fourth diffraction wave functions are wave functions of different virtual image fields of view.

[0058] Please refer to Figure 12. Figure 12 is a schematic diagram illustrating different virtual image fields of view. As shown in Figures 11A and 12, the virtual image presented by the first output beam La3 corresponds to the first virtual image field of view VFa as seen by the user's eye in Figure 12. As shown in Figures 11B and 12, the virtual image presented by the second output beam Lb3 corresponds to the second virtual image field of view VFb as seen by the user's eye in Figure 12. As shown in Figures 11C and 12, the virtual image presented by the third output beam Lc3 corresponds to the third virtual image field of view VFc as seen by the user's eye in Figure 12. As shown in Figures 11D and 12, the virtual image presented by the fourth output beam Ld3 corresponds to the fourth virtual image field of view VFd as seen by the user's eye in Figure 12. For example, the first virtual image field of view VFa of the first diffraction wave function is about 60 degrees, the second virtual image field of view VFb of the second diffraction wave function is about 50 degrees, the third virtual image field of view VFc of the third diffraction wave function is about 40 degrees, and the fourth virtual image field of view VFd of the fourth diffraction wave function is about 30 degrees, but this disclosure is not limited to these.

[0059] Please refer to Figure 13. Figure 13 is a front view illustrating a waveguide device 420 according to another embodiment of the present disclosure. As shown in Figure 13, in this embodiment, the waveguide device 420 includes a light-transmitting substrate 421, a first image coupling element 422a, a first image coupling element 423a, a second image coupling element 422b, a second image coupling element 423b, a third image coupling element 422c, and a third image coupling element 423c. The light-transmitting substrate 421 includes a central region 421a and a peripheral region 421b surrounding the central region 421a. The first image coupling element 422a is located in the peripheral region 421b and is configured to diffract a first light beam La (refer to Figure 3A) propagating in the light-transmitting substrate 421. The first image coupling element 423a is located in the central region 421a and is configured to diffract the diffracted first light beam La propagating in the light-transmitting substrate 421. The second image coupling element 422b is located in the peripheral region 421b and is configured to diffract the second light beam Lb (refer to Figure 3B) into the light-transmitting substrate 421. The second image coupling element 423b is located in the central region 421a and is configured to diffract the diffracted second light beam Lb propagating in the light-transmitting substrate 421. The third image coupling element 422c is located in the peripheral region 421b and is configured to diffract the third light beam Lc (refer to Figure 3C) into the light-transmitting substrate 421. The third image coupling element 423c is located in the central region 421a and is configured to diffract the diffracted third light beam Lc propagating in the light-transmitting substrate 421.

[0060] Specifically, in this embodiment, the first image coupling element 423a includes a first diffraction grating, the second image coupling element 423b includes a second diffraction grating, and the third image coupling element 423c includes a third diffraction grating. The first, second, and third diffraction gratings intersect each other. That is, the first, second, and third diffraction gratings physically pass through each other. Therefore, the waveguide device 420 can have a smaller size.

[0061] In this embodiment, the first diffraction grating of the first image coupling element 423a is configured to diffract red light R. For example, the wavelength of the first light beam La diffracted by the first diffraction grating of the first image coupling element 423a is approximately 632 nanometers (within the wavelength range of red light R). The second diffraction grating of the second image coupling element 423b is configured to diffract green light G. For example, the wavelength of the second light beam Lb diffracted by the second diffraction grating of the second image coupling element 423b is approximately 532 nanometers (within the wavelength range of green light G). The third diffraction grating of the third image coupling element 423c is configured to diffract blue light B. For example, the wavelength of the third light beam Lc diffracted by the third diffraction grating of the third image coupling element 423c is approximately 465 nanometers (within the wavelength range of blue light B).

[0062] Refer to Figure 14. Figure 14 is a front view illustrating a waveguide device 520 according to another embodiment of the present disclosure. As shown in Figure 14, in this embodiment, the waveguide device 420 includes light-transmitting substrates 521a, 521b, 521c, a first image coupling element 522a, a first image coupling element 523a, a second image coupling element 522b, a second image coupling element 523b, a third image coupling element 522c, and a third image coupling element 523c. The functions of the first image input element 522a, the first image output element 523a, the second image input element 522b, the second image output element 523b, the third image input element 522c, and the third image output element 523c are the same as those of the first image input element 422a, the first image output element 423a, the second image input element 422b, the second image output element 423b, the third image input element 422c, and the third image output element 423c. The differences between the embodiments shown in Figures 13 and 14 are discussed below.

[0063] As shown in Figure 14, in this embodiment, the light-transmitting substrate 521a includes a central region 521a1 and a peripheral region 521a2 surrounding the central region 521a1. The light-transmitting substrate 521b includes a central region 521b1 and a peripheral region 521b2 surrounding the central region 521b1. The light-transmitting substrate 521c includes a central region 521c1 and a peripheral region 521c2 surrounding the central region 521c1. A first image coupling element 522a and a first image coupling element 523a are respectively located in the peripheral region 521a2 and the central region 521a1 of the light-transmitting substrate 521a. A second image coupling element 522b and a second image coupling element 523b are respectively located in the peripheral region 521b2 and the central region 521b1 of the light-transmitting substrate 521b. The third image coupling element 522c and the third image coupling element 523c are located in the peripheral region 521c2 and the central region 521c1 of the light-transmitting substrate 521c, respectively. That is, the combination of the light-transmitting substrate 521a, the first image coupling element 522a, and the first image coupling element 523a is responsible for diffracting red light R. The combination of the light-transmitting substrate 521b, the second image coupling element 522b, and the second image coupling element 523b is responsible for diffracting green light G. The combination of the light-transmitting substrate 521c, the third image coupling element 522c, and the third image coupling element 523c is responsible for diffracting blue light B.

[0064] Please refer to Figure 15. Figure 15 is a front view illustrating a waveguide device 620 according to another embodiment of the present disclosure. As shown in Figure 15, in this embodiment, the waveguide device 620 includes a light-transmitting substrate 621, a first image coupling element 622a, a first image coupling element 623a, a second image coupling element 622b, a second image coupling element 623b, a third image coupling element 622c, and a third image coupling element 623c. The light-transmitting substrate 621 includes a central region 621a and a peripheral region 621b surrounding the central region 621a. The first image coupling element 622a is located in the peripheral region 621b and is configured to diffract a first light beam La (refer to Figure 3A) propagating in the light-transmitting substrate 621. The first image coupling element 623a is located in the central region 621a and is configured to diffract the diffracted first light beam La propagating in the light-transmitting substrate 621. The second image coupling element 622b is located in the peripheral region 621b and is configured to diffract the second light beam Lb (refer to Figure 3B) into the light-transmitting substrate 621. The second image coupling element 623b is located in the central region 621a and is configured to diffract the diffracted second light beam Lb propagating in the light-transmitting substrate 621. The third image coupling element 622c is located in the peripheral region 621b and is configured to diffract the third light beam Lc (refer to Figure 3C) into the light-transmitting substrate 621. The third image coupling element 623c is located in the central region 621a and is configured to diffract the diffracted third light beam Lc propagating in the light-transmitting substrate 621.

[0065] Specifically, in this embodiment, the first image coupling element 623a includes a first diffraction grating, the second image coupling element 623b includes a second diffraction grating, and the third image coupling element 623c includes a third diffraction grating. The first, second, and third diffraction gratings intersect each other. That is, the first, second, and third diffraction gratings physically pass through each other. Therefore, the waveguide device 620 can have a smaller size.

[0066] In this embodiment, the first diffraction grating of the first image coupling element 623a is configured to diffract red light R within a first diffraction angle range. For example, the first diffraction grating of the first image coupling element 623a is configured to diffract light with a wavelength of approximately 632 nanometers, causing it to propagate within the first diffraction angle (as shown by the red light R in Figure 15). The second diffraction grating of the second image coupling element 623b is configured to diffract red light R within a second diffraction angle range. For example, the second diffraction grating of the second image coupling element 623b is configured to diffract light with a wavelength of approximately 632 nanometers, causing it to propagate within the first diffraction angle plus 5 degrees (as shown by the red light R' in Figure 15). The third diffraction grating of the third image coupling element 623c is configured to diffract red light R within a third diffraction angle range. For example, the third diffraction grating of the third image coupling element 623c is configured to diffract light with a wavelength of approximately 632 nanometers, causing it to propagate at a first diffraction angle plus 10 degrees (as shown by the red light R'' in Figure 15).

[0067] Please refer to Figure 16. Figure 16 is a front view illustrating a waveguide device 720 according to another embodiment of the present disclosure. As shown in Figure 16, in this embodiment, the waveguide device 720 includes light-transmitting substrates 721a, 721b, 721c, a first image coupling element 722a, a first image coupling element 723a, a second image coupling element 722b, a second image coupling element 723b, a third image coupling element 722c, and a third image coupling element 723c. The functions of the first image input element 722a, the first image output element 723a, the second image input element 722b, the second image output element 723b, the third image input element 622c, and the third image output element 623c are the same as those of the first image input element 622a, the first image output element 623a, the second image input element 622b, the second image output element 623b, the third image input element 622c, and the third image output element 623c, respectively. The differences between the embodiments shown in Figures 15 and 16 are discussed below.

[0068] As shown in Figure 16, in this embodiment, the light-transmitting substrate 721a includes a central region 721a1 and a peripheral region 721a2 surrounding the central region 721a1. The light-transmitting substrate 721b includes a central region 721b1 and a peripheral region 721b2 surrounding the central region 721b1. The light-transmitting substrate 721c includes a central region 721c1 and a peripheral region 721c2 surrounding the central region 721c1. A first image coupling element 722a and a first image coupling element 723a are respectively located in the peripheral region 721a2 and the central region 721a1 of the light-transmitting substrate 721a. A second image coupling element 722b and a second image coupling element 723b are respectively located in the peripheral region 721b2 and the central region 721b1 of the light-transmitting substrate 721b. The third image coupling element 722c and the third image coupling element 723c are located in the peripheral region 721c2 and the central region 721c1 of the light-transmitting substrate 721c, respectively. That is, the combination of the light-transmitting substrate 721a, the first image coupling element 722a, and the first image coupling element 723a is responsible for diffracting the red light R at a first diffraction angle. The combination of the light-transmitting substrate 721b, the second image coupling element 722b, and the second image coupling element 723b is responsible for diffracting the red light R at the first diffraction angle plus 5 degrees. The combination of the light-transmitting substrate 721c, the third image coupling element 722c, and the third image coupling element 723c is responsible for diffracting the red light R at the first diffraction angle plus 10 degrees.

[0069] From the detailed description of the specific embodiments disclosed above, it is evident that in the waveguide device and optical device disclosed herein, by disposing of a plurality of image coupling elements in the peripheral area of ​​the light-transmitting substrate and correspondingly disposing of a plurality of image coupling elements in the central area of ​​the light-transmitting substrate, independent optical guidance and output control of a plurality of light beams can be achieved. Therefore, the waveguide device and optical device disclosed herein can effectively solve the bottlenecks encountered in the prior art, such as potential limitations in virtual image position, virtual image distance, or virtual image field of view, thereby providing more flexible and diverse virtual image presentation effects.

[0070] Although this disclosure has been described in considerable detail with reference to certain embodiments thereof, other embodiments are also possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments included in this disclosure.

[0071] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of this disclosure without departing from the scope or spirit of this disclosure. In view of the foregoing, this disclosure is intended to cover modifications and variations thereof, provided they fall within the scope of the following claims. [Simplified Explanation of the Diagram]

[0028] To make the above and other objects, features, advantages and embodiments of this disclosure more apparent and understandable, the accompanying drawings are described below: Figure 1 is a schematic diagram illustrating an optical device according to one embodiment of this disclosure. Figure 2 is a front view illustrating one of the waveguide devices in Figure 1. Figure 3A is a partial schematic diagram illustrating the waveguide device in Figure 2. Figure 3B is another partial schematic diagram illustrating the waveguide device in Figure 2. Figure 3C is another partial schematic diagram illustrating the waveguide device in Figure 2. Figure 3D is another partial schematic diagram illustrating the waveguide device in Figure 2. Figure 4 is a schematic diagram illustrating different virtual image positions. Figure 5 is a partial schematic diagram illustrating the first image coupling element in Figure 3A. Figure 6 is a schematic diagram illustrating an optical exposure system for manufacturing a diffraction element. Figure 7 is a partial schematic diagram illustrating a light-transmitting substrate with a first image coupling element according to another embodiment of this disclosure. Figure 8 is a partial schematic diagram illustrating the first image coupling element according to another embodiment of this disclosure. Figure 9A is a partial schematic diagram illustrating a waveguide device according to another embodiment of the present disclosure. Figure 9B is another partial schematic diagram illustrating the waveguide device in Figure 9A. Figure 9C is another partial schematic diagram illustrating the waveguide device in Figure 9A. Figure 9D is another partial schematic diagram illustrating the waveguide device in Figure 9A. Figure 10 is a schematic diagram illustrating different virtual image distances. Figure 11A is a partial schematic diagram illustrating a waveguide device according to another embodiment of the present disclosure. Figure 11B is another partial schematic diagram illustrating the waveguide device in Figure 11A. Figure 11C is another partial schematic diagram illustrating the waveguide device in Figure 11A. Figure 11D is another partial schematic diagram illustrating the waveguide device in Figure 11A. Figure 12 is a schematic diagram illustrating different virtual image fields of view. Figure 13 is a front view illustrating a waveguide device according to another embodiment of the present disclosure. Figure 14 is a front view illustrating a waveguide device according to another embodiment of the present disclosure. Figure 15 is a front view illustrating a waveguide device according to another embodiment of the present disclosure. Figure 16 is a front view illustrating a waveguide device according to another embodiment of this disclosure. [Biomaterial Storage]

[0073] Domestic storage information (please note in order of storage institution, date, and number): None. International storage information (please note in order of storage country, institution, date, and number): None.

Claims

1. A waveguide device comprising: at least one light-transmitting substrate, including a central region and a peripheral region surrounding the central region; a first image coupling element located in the peripheral region and configured to diffract a first light beam propagating in the at least one light-transmitting substrate; a first image coupling element located in the central region and configured to diffract the diffracted first light beam propagating in the at least one light-transmitting substrate; a second image coupling element located in the peripheral region and configured to diffract a second light beam propagating in the at least one light-transmitting substrate; and a second image coupling element located in the central region and configured to diffract the diffracted second light beam propagating in the at least one light-transmitting substrate, wherein the first light beam and the second light beam have the same wavelength, the first image coupling element is configured to diffract the diffracted first light beam propagating at a first diffraction angle, and the second image coupling element is configured to diffract the diffracted second light beam propagating at a second diffraction angle different from the first diffraction angle.

2. The waveguide device as claimed in claim 1, wherein the first image coupling element and the first image coupling element are radially aligned, and the second image coupling element and the second image coupling element are radially aligned.

3. The waveguide device as claimed in claim 1, wherein the first image coupling element includes a first diffraction grating, the second image coupling element includes a second diffraction grating, and the first diffraction grating and the second diffraction grating intersect each other.

4. The waveguide device as claimed in claim 1, wherein the at least one light-transmitting substrate includes a first light-transmitting substrate and a second light-transmitting substrate, the first image coupling element and the first image coupling element are located on the first light-transmitting substrate, and the second image coupling element and the second image coupling element are located on the second light-transmitting substrate.

5. A waveguide device comprising: at least one light-transmitting substrate, including a central region and a peripheral region surrounding the central region; a first image coupling element located in the peripheral region and configured to diffract a first light beam propagating in the at least one light-transmitting substrate; a first image coupling element located in the central region and configured to diffract the diffracted first light beam propagating in the at least one light-transmitting substrate; a second image coupling element located in the peripheral region and configured to diffract a second light beam propagating in the at least one light-transmitting substrate; and a second image coupling element located in the central region and configured to diffract the diffracted second light beam propagating in the at least one light-transmitting substrate, wherein the first light beam and the second light beam have the same wavelength, the first image coupling element conforms to a first diffraction wave function, and the second image coupling element conforms to a second diffraction wave function different from the first diffraction wave function.

6. The waveguide device as claimed in claim 5, wherein the first diffraction wavefunction is a wavefunction of a first virtual image distance, and the second diffraction wavefunction is a wavefunction of a second virtual image distance that is different from the first virtual image distance.

7. The waveguide device as claimed in claim 5, wherein the first diffraction wave function is a wave function of a first virtual image field of view, and the second diffraction wave function is a wave function of a second virtual image field of view, different from the first virtual image field of view.

8. A waveguide device comprising: at least one light-transmitting substrate, including a central region and a peripheral region surrounding the central region, wherein the central region is rotatably connected to the peripheral region; a first image coupling element located in the peripheral region and configured to diffract a first light beam propagating in the at least one light-transmitting substrate; a first image coupling element located in the central region and configured to diffract the diffracted first light beam propagating in the at least one light-transmitting substrate; a second image coupling element located in the peripheral region and configured to diffract a second light beam propagating in the at least one light-transmitting substrate; and a second image coupling element located in the central region and configured to diffract the diffracted second light beam propagating in the at least one light-transmitting substrate.

9. The waveguide device as claimed in claim 8, wherein the first beam and the second beam have different wavelengths.

10. The waveguide device as claimed in claim 8, wherein the first beam and the second beam have the same wavelength.

11. An optical device comprising: a housing; a waveguide device comprising: at least one light-transmitting substrate rotatably connected to the housing, and including a central region and a peripheral region surrounding the central region; a first image coupling element located in the peripheral region and configured to diffract a first light beam in the at least one light-transmitting substrate; a first image coupling element located in the central region and configured to diffract the diffracted first light beam in the at least one light-transmitting substrate; a second image coupling element located in the peripheral region and configured to diffract a second light beam in the at least one light-transmitting substrate; and a second image coupling element located in the central region and configured to diffract the diffracted second light beam in the at least one light-transmitting substrate; and a projector disposed on the housing and configured to emit the first light beam and the second light beam toward the peripheral region along an optical path.

12. The optical device as claimed in claim 11, wherein the first beam and the second beam have the same wavelength.

13. The optical device as claimed in claim 12, wherein the first image coupling element is configured to diffract the diffracted first light beam at a first diffraction angle, and the second image coupling element is configured to diffract the diffracted second light beam at a second diffraction angle different from the first diffraction angle.

14. The optical device as claimed in claim 12, wherein the first image coupling element conforms to a first diffraction wave function, and the second image coupling element conforms to a second diffraction wave function different from the first diffraction wave function.

15. The optical device as claimed in claim 14, wherein the first diffraction wave function is a wave function of a first virtual image distance, and the second diffraction wave function is a wave function of a second virtual image distance that is different from the first virtual image distance.

16. The optical device as claimed in claim 14, wherein the first diffraction wave function is a wave function of a first virtual image field of view, and the second diffraction wave function is a wave function of a second virtual image field of view that is different from the first virtual image field of view.

17. The optical device as claimed in claim 11, wherein the first image coupling element includes a first diffraction grating, the second image coupling element includes a second diffraction grating, and the first diffraction grating and the second diffraction grating intersect each other.

18. The optical device as claimed in claim 11, wherein the central region is rotatably connected to the peripheral region.

Images