Patent Application
20230029214
This application claims the priority benefit of China patent application serial no. 202110828513.1, filed on Jul. 22, 2021. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
The invention relates to a display apparatus; more particularly, the invention relates to a head-mounted display (HMD) apparatus.
With the advancement of display technologies, a near eye display (NED) and a head-mounted display (HMD) have been developed and are products with great development potential. Relevant technologies that have been applied into the NED and/or HMD may be categorized into an augmented reality (AR) technology and a virtual reality (VR) technology. However, the HMD apparatus with the AR technology is not only required to have light weight but also required to allow users to achieve a visual balance when the users respond to different light intensities and brightness of displayed images in different environments and fields.
For instance, in a brighter environment (such as an outdoor environment), the brightness of the displayed image is lower than the light intensity of the real world, and thus the HMD apparatus is required to be able to modulate (reduce) the light intensity of the real world. In addition, in order to accomplish wearing comfort, the center of gravity of the HMD apparatus must be close to the center of gravity of the user's head when the user wears the HMD apparatus. Therefore, the distance between a lens of the HMD apparatus and the eyes is adjusted to be as short as possible. At this time, if it is intended to increase the use of a pair of conventional vision correction eyeglasses, such use may be detrimental to the use of the HMD apparatus with a short distance.
The information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the Background section does not mean that one or more problems to be resolved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art.
The invention provides a head-mounted display (HMD) apparatus, which requires no additional eyeglasses, optimizes the center of gravity of a user wearing the HMD apparatus, and improves wearing comfort of the user; at the same time, good display effects may be achieved even when light intensities are changed.
Other objectives and advantages of the invention may further be learned from technical features disclosed in the invention.
In order to achieve one or a part or all of the foregoing objectives or other objectives, an embodiment of the invention provides an HMD apparatus which includes an image source, a light guiding element, a first modulating element, and a second modulating element. The image source provides an image beam. The light guiding element is arranged on an image beam transmission path to transmit the image beam. The light guiding element has a first surface and a second surface opposite to each other. The image beam undergoes a total internal reflection at the first surface, and the image beam is emitted from the second surface. The first modulating element is arranged on one side of the first surface of the light guiding element and is configured to adjust a transmittance of an ambient beam. The light guiding element is arranged between the first modulating element and the second modulating element, and the second modulating element is configured to adjust a focus position of the image beam.
In view of the above, one or more embodiments of the invention have at least one of the following advantages or effects. In the HMD apparatus provided in one or more embodiments of the invention, the image source provides the image beam to the light guiding element and reflects and transmits the image beam to human eyes. Here, the light guiding element is arranged between the first modulating element and the second modulating element, the first modulating element is configured to adjust the transmittance of the ambient beam, and the second modulating element is configured to adjust the focus position of the image beam. Therefore, the first modulating element may be applied to modulate the intensity of the ambient beam transmitted to the human eyes, so as to be adapted to different condition; the second modulating element may be applied to modulate the focus position of the image beam, so as to improve the optical effects in response to different degrees of vision of the users. Thereby, the users need not wear additional eyeglasses, thereby optimizing the center of gravity of the users wearing the HMD apparatus and improving the wearing comfort, and at the same time, good display effects may be achieved even when the light intensities in the environment are different.
Other objectives, features and advantages of the present invention will be further understood from the further technological features disclosed by the embodiments of the present invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” etc., is used with reference to the orientation of the Figure(s) being described. The components of the present invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. On the other hand, the drawings are only schematic and the sizes of components may be exaggerated for clarity. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Similarly, the terms “facing,” “faces” and variations thereof herein are used broadly and encompass direct and indirect facing, and “adjacent to” and variations thereof herein are used broadly and encompass directly and indirectly “adjacent to”. Therefore, the description of “A” component facing “B” component herein may contain the situations that “A” component directly faces “B” component or one or more additional components are between “A” component and “B” component. Also, the description of “A” component “adjacent to” “B” component herein may contain the situations that “A” component is directly “adjacent to” “B” component or one or more additional components are between “A” component and “B” component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.
The light guiding element 120 is arranged on a transmission path of the image beam L1 provided by the image source 110 and configured to transmit the image beam L1 to the user's eye E. In this embodiment, the light guiding element 120 is composed of, for instance, an optical structure capable of transmitting the image beam L1, such as a freeform waveguide or a prism, which should however not be construed as a limitation to the invention. The light guiding element 120 includes at least one coupling structure 122 which is arranged corresponding to a relative position of the user's eye E (the at least one coupling structure 122 is arranged on the transmission path of the image beam L1). When the image beam L1 is transmitted to the coupling structure 122, the image beam L1 may be reflected into the user's eye E to form a virtual image. The type and the number of the coupling structure 122 may be determined according to actual requirements, which should however not be construed as a limitation to the invention. For instance, in an embodiment, the coupling structure 122 may be a reflective surface formed by combining two different components of part of the light guiding element 120 (e.g., with different refractive indices), and the reflective surface is a freeform curved surface.
The light guiding element 120 has a first surface S1 and a second surface S2 opposite to each other. For instance, the first surface S1 is located on one surface of the light guiding element 120 facing away from the user's eye E, and the second surface S2 is located on the other surface of the light guiding element 120 facing the user's eye E. The image beam L1 undergoes a total internal reflection at the first surface S1. In other words, the image beam L1 is not emitted from the first surface S1. Here, a method of producing the total internal reflection of the image beam L1 at the first surface S1 is performed by modulating the difference between the refractive index of the light guiding element 120 and the refractive index of an external structure (such as the first modulating element 130 described later), for instance, so as to allow the image beam L1 to undergo the total internal reflection, or by modulating an angle at which the image beam L1 enters the light guiding element 120, so as to allow the image beam L1 to undergo the total internal reflection at the first surface S1, which should however not be construed as a limitation to the invention. the invention is not limited to this.
On the other hand, the image beam L1 is emitted from the second surface S2 and transmitted to the user's eye E. For instance, the image beam L1 undergoes the total internal reflection at one portion of the second surface S2, and the image beam L1 is emitted from another portion of the second surface S2. To be specific, the second surface S2 of the light guiding element 120 includes the non-light-emitting region A1 and a light-emitting region A2. Here, the location of the light-emitting region A2 covers (is related to) the location of the user's eye E (i.e., where the human eye is generally located). In particular, the second surface S2 of the light guiding element 120 may have only the light-emitting region A2 and the non-light-emitting region A1. The image beam L1 undergoes the total internal reflection in the non-light-emitting region A1 of the second surface S2, and the image beam L1 is transmitted to the outside through the light-emitting region A2 (e.g., the second modulating element 140 described later), so that the user may observe the image from the light-emitting region A2. Here, a method of producing the total internal reflection of the image beam L1 at the non-light-emitting region A1 of the second surface S2 is performed by modulating the difference between the refractive index of the light guiding element 120 and the refractive index of the external structure (e.g., the first modulating element 130 described later), for instance, so as to allow the image beam L1 to undergo the total internal reflection, or by modulating an angle at which the image beam L1 enters the light guiding element 120, so as to allow the image beam L1 to undergo the total internal reflection, which should however not be construed as a limitation to the invention. In an embodiment, the non-light-emitting region A1 of the first surface S1 and/or the second surface S2 of the light guiding element 120 may be designed to have an optical microstructure for enhancing the effect of the total internal reflection of the image beam L1, which should however not be construed as a limitation to the invention.
In this embodiment, the HMD apparatus 100 further includes a lens module 150 arranged on the transmission path of the image beam L1 and located on a transmission path between the image source 110 and the light guiding element 120. The lens module 150 is composed of at least one optical lens for transmitting the image beam L1 to the light guiding element 120. In this embodiment, the lens module 150 includes at least one axisymmetric aspheric decentered lens. Thereby, the geometric design of the coupling structure 122 in the light guiding element 120 may be further made of a non-axisymmetric freeform curved surface. As such, the overall thickness of the light guiding element 120 may be reduced, which should however not be construed as a limitation to the invention. In other embodiments, the transmission path between the image source 110 and the light guiding element 120 may further include other optical elements, such as a reflective mirror, so that the image beam L1 may be transferred to the light guiding element 120 smoothly.
Specifically, the first modulating element 130 is arranged on one side of the first surface S1 of the light guiding element 120 and is configured to adjust a transmittance of an ambient beam L2. Note that the ambient beam L2 represents the light beam transmitted from the outside to the user's eye E sequentially through the first modulating element 130, the light guiding element 120, and the second modulating element 140; namely, the scene of the outside world in front of the user. Particularly, in this embodiment, the first modulating element 130 is directly disposed on the first surface S1 of the light guiding element 120. Therefore, the image beam L1 transmitted within the light guiding element 120 may achieve the effect of the total internal reflection on the first surface S1 of the light guiding element 120 due to an incident angle and the difference between the refractive index of the light guiding element 120 and the refractive index of the first modulating element 130, which should however not be construed as a limitation to the invention. In another embodiment, an air gap may be designed between the first modulating element 130 and the light guiding element 120, so as to achieve the effect of the total internal reflection on the first surface S1 of the light guiding element 120. The first modulating element 130 is, for instance, an electrically controllable element. Therefore, the transmittance of the ambient beam L2 may be modulated according to different electrical parameters, thereby changing the intensity of the ambient beam L2 transmitted to the human eye. For instance, the HMD apparatus 100 further includes a light sensing element and a controller (not shown). The controller is electrically connected to the light sensing element and the first modulating element 130. The light sensing element is configured to receive the intensity of the ambient beam L2 to provide a modulation signal to the controller, and the controller controls the first modulating element 130 according to the modulation signal.
The second modulating element 140 is arranged on one side of the second surface S2 of the light guiding element 120 (i.e., the light guiding element 120 is located between the first modulating element 130 and the second modulating element 140), and is configured to modulate a focus position of the image beam L1 (i.e., to change the distance between the focus position and the user's eye E), so that the HMD apparatus 100 may accommodate the needs of different users. That is, the HMD apparatus 100 provided in this embodiment may perform a vision compensation function, so as to be adapted to users with different degrees of vision in no need of replacing or additionally wearing any vision compensation eyeglasses. Specifically, in this embodiment, the second modulating element 140 is directly disposed on the second surface S2 of the light guiding element 120. Therefore, the image beam L1 transmitted within the light guiding element 120 may achieve the effect of the total internal reflection at the second surface S2 of the light guiding element 120 due to the incident angle and the difference between the refractive index of the light guiding element 120 and the refractive index of the second modulating element 140, which should however not be construed as a limitation to the invention. In another embodiment, an air gap may be designed between the second modulating element 140 and the light guiding element 120, so as to achieve the effect of the total internal reflection on the second surface S2 of the light guiding element 120. The second modulating element 140 is, for instance, an electrically controllable element. Therefore, the focus position of the image beam L1 may be modulated according to different electrical parameters, so as to improve the optical effect in response to different degrees of the vision of the users. The light path transmission mode of the image beam L1 (focusing toward the user's eye E) shown in
Specifically, in an embodiment where both the first modulating element 130 and the second modulating element 140 are the electrically controllable elements, the first modulating element 130 and the second modulating element 140 may have an electrode structure, and the electrode structure may be made of materials with good transmittance (e.g., transparent) in the visible light band, such as a light transmitting electrode or a micro-structured electrode, which should however not be construed as a limitation to the invention.
As shown in
To sum up, in the HMD apparatus provided in one or more embodiments of the Invention, the image source provides the image beam to the light guiding element, and the image beam is reflected and transmitted to the human eye. Here, the light guiding element is arranged between the first modulating element and the second modulating element, the first modulating element is configured to adjust the transmittance of the ambient beam, and the second modulating element is configured to adjust the focus position of the image beam. Therefore, the first modulating element may be configured to modulate the intensity of the ambient beam transmitted to the human eye, so as to be adapted to different scenarios and conditions, and the second modulating element may be configured to modulate the focus position of the image beam in response to different degrees of the vision of the users, so as to render favorable optical effects. As a result, the users need not wear additional eyeglasses, thereby optimizing the center of gravity of the users wearing the HMD apparatus and improving the wearing comfort, and at the same time, good display effects may be achieved even when the light intensities in the environment are different.
The foregoing description of the preferred of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the term “the invention”, “the present invention” or the like does not necessarily limit the claim scope to a specific embodiment, and the reference to particularly preferred exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. Moreover, these claims may refer to use “first”, “second”, etc. following with noun or element. Such terms should be understood as a nomenclature and should not be construed as giving the limitation on the number of the elements modified by such nomenclature unless specific number has been given. The abstract of the disclosure is provided to comply with the rules requiring an abstract, which will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims. Moreover, no element and component in the present invention is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202110828513.1 | Jul 2021 | CN | national |
