Head-mounted display device

Abstract

The present invention provides a head-mounted display device, which includes a projection device, a waveguide element, and a light-shielding element. The projection device is used to provide an image light beam, and the projection device includes a lens module, and the lens module is used to transmit the image light beam. At least one waveguide element has a light inlet end and a light outlet end, the light inlet end is used to receive the image light beam, and the image light beam is transmitted by at least one waveguide element and emitted from the light outlet end. The light-shielding element is disposed between the projection device and the light inlet end of at least one waveguide element, wherein the image light beam leaves the projection device and converges to a light barrier, the light barrier is located outside the projection device, and the light barrier is located in the at least one waveguide element. The head-mounted display device of the present invention can effectively reduce the generation of unexpected light or light spots, so as to avoid displaying noise or ghost images in the display screen.

Description

[0001] This application is a divisional application of a Chinese invention application with an application date of May 31, 2018, an application number of 201810571161.4, and a title of "Head-Mounted Display Device". Technical Field

[0002] The present invention relates to a display device, and particularly to a head-mounted display device. Background Art

[0003] Near Eye Displays (NEDs) and Head-mounted Displays (HMDs) are currently next-generation killer products with great production potential. In the related applications of near-eye display technology, it can currently be divided into Augmented Reality (AR) technology and Virtual Reality (VR) technology. For AR technology, relevant developers are currently working on how to provide the best image quality on the premise of being thin and light. However, in the optical architecture of AR, how to use limited space to reduce stray light or ghosting, so that users have better visual quality and provide a good user experience, is one of the important topics currently.

[0004] The "Background Art" paragraph is only used to help understand the content of the present invention. Therefore, the content disclosed in the "Background Art" paragraph may include some known technologies that are not known to those skilled in the art. The content disclosed in the "Background Art" paragraph does not represent the problems to be solved by the content or one or more embodiments of the present invention, which have been known or recognized by those skilled in the art before the filing of the present invention application. Summary of the Invention

[0005] The present invention provides a head-mounted display device, which can effectively reduce the generation of unexpected light or light spots to avoid displaying noise or ghosting in the display screen.

[0006] Other objects and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

[0007] To achieve one or part or all of the above objects or other objects, an embodiment of the present invention provides a head-mounted display device, which includes a projection device, at least one waveguide element, and a light-shielding element. The projection device is used to provide an image beam. The projection device includes a lens module, and the lens module is used to transmit the image beam. At least one waveguide element has a light inlet end and a light outlet end. The light inlet end is used to receive the image beam, and the image beam is transmitted by the at least one waveguide element and emitted from the light outlet end. The light-shielding element is disposed between the projection device and the light inlet end of the at least one waveguide element, wherein the image beam leaves the projection device and converges to a light stop. The light stop is located outside the projection device, and the light stop is located on the at least one waveguide element.

[0008] Based on the above, the embodiments of the present invention have at least one of the following advantages or effects. In the head-mounted display device according to an embodiment of the present invention, since the light-shielding element is disposed between the projection device and the light inlet end of the waveguide element, the excess and divergent partial image beams of the image beam provided by the projection device can be blocked by the light-shielding element when passing through the light-shielding element. In this way, unexpected light or light spots can be effectively reduced to avoid noise or ghost images in the virtual image, thereby improving the optical display quality of the head-mounted display device.

[0009] To make the above features and advantages of the present invention more obvious and understandable, specific embodiments are hereinafter given and described in detail in conjunction with the accompanying drawings as follows. Description of the Drawings

[0010] Figure 1 A three-dimensional schematic diagram of the head-mounted display device according to an embodiment of the present invention.

[0011] Figure 2 For Figure 1 a schematic diagram of the waveguide element and the light-shielding element.

[0012] Figure 3 For Figure 1 a schematic diagram of another perspective of the head-mounted display device.

[0013] Figure 4 For Figure 1 an optical characteristic curve diagram of the head-mounted display device.

[0014] Figure 5 A schematic diagram of the head-mounted display device according to another embodiment of the present invention.

[0015] Figure 6 A schematic diagram of the head-mounted display device according to another embodiment of the present invention.

[0016] Figure 7 A schematic diagram of the head-mounted display device according to another embodiment of the present invention.

[0017] Figure 8A and Figure 8B are respectively Figure 7 the enlarged side views of region A of

[0018] Figure 9 a schematic diagram of a head-mounted display device according to another embodiment of the present invention.

[0019] Figure 10 a schematic diagram of a head-mounted display device according to another embodiment of the present invention. Detailed implementation manners

[0020] Regarding the foregoing and other technical contents, features and effects of the present invention, they will be clearly presented in the following detailed description of a preferred embodiment in conjunction with the reference views. The directional terms (such as: up, down, left, right, front or back, etc.) mentioned in the following embodiments are only for reference to the directions of the attached views. Therefore, the directional terms used are for illustration and not for limiting the present invention.

[0021] Figure 1 a three-dimensional schematic diagram of a head-mounted display device according to an embodiment of the present invention. Figure 2 is Figure 1 a schematic diagram of the waveguide element and the light-shielding element of Figure 3 is Figure 1 another perspective schematic diagram of the head-mounted display device of Figures 1 to 3 Referring to

[0022] , in this embodiment, the head-mounted display device 100 includes a projection device 110, at least one waveguide element 120, and a light-shielding element 130. The head-mounted display device 100 is, for example, a Near Eye Display (NED) or a Head-mounted Display (HMD), and the display technology can use Augmented Reality (AR) technology or Virtual Reality (VR) technology, but the present invention is not limited thereto.

[0022] In this embodiment, the projection device 110 is used to provide an image beam L, and the image beam L has a stop ST. Specifically, the projection device 110 includes, for example, an illumination system that provides an illumination beam, an imaging device that converts the illumination beam into the image beam L, and a lens module (not shown) that transmits the image beam L to the waveguide element 120. In this embodiment, the projection device 110 can be used in various types of head-mounted displays. The imaging device is, for example, a Digital Micromirror Device (DMD), a reflective Liquid Crystal on Silicon (LCOS), or a transmissive spatial light modulator, such as a Transparent Liquid Crystal Panel, etc., for converting the illumination beam provided by the illumination system into the image beam L. In addition, in other embodiments, the projection device 110 includes, for example, Micro Light Emitting Diodes, and the Micro Light Emitting Diodes are used as the imaging device to generate the image beam L.

[0023] In this embodiment, the image beam L is transmitted through the lens module and the waveguide element 120 to a projection target P, such as a human eye. Figure 1 and Figure 2 The illustrated projection device 110 and waveguide element 120 are only for illustrative purposes and do not limit the present invention. Specifically, in this embodiment, the image beam L exits the projection device 110 and converges to the stop ST. The stop ST has the smallest cross-sectional area for beam constriction of the image beam L. In other words, the image beam L is projected by the projection device 110 and then converges to the stop ST, and diverges after passing through the stop ST. In this embodiment, the stop ST is located outside the projection device 110, for example, between the light-shielding element 130 and the waveguide element 120. Specifically, the stop ST is located at the light entrance end 122, which can enable the head-mounted display device 100 to have better optical display quality. In other embodiments, the stop ST can be located inside the waveguide element 120, such that the light entrance end 122 is located between the projection device 110 and the stop ST, but is not limited thereto.

[0024] In this embodiment, the waveguide element 120 has a light input end 122 and a light output end 124. Specifically, the light input end 122 is used to receive the image light beam L. The image light beam L is optically transmitted inside the waveguide element 120 and emitted from the light output end 124 to be transmitted to the projection target P (the human eye in this embodiment), so that the human eye can receive the virtual image IM. In this embodiment, the light input end 122 and the light output end 124 of the waveguide element 120 respectively have a diffraction structure (Grating / Diffraction structure). For example, the diffraction structure can be attached to the light input end 122 and the light output end 124 of the waveguide element 120 in a pasting manner, or the diffraction structure can be formed on the light input end 122 and the light output end 124 of the waveguide element 120 in an integrally formed manner (such as by etching), but the present invention is not limited thereto. For example, the waveguide element 120 includes a first diffraction structure and a second diffraction structure, wherein the first diffraction structure is located at the light input end 122, and the second diffraction structure is located at the light output end 124. In other embodiments, the waveguide element 120 may further include multiple diffraction structures, but the present invention is not limited thereto. In addition, the present invention does not limit the type, quantity, and kind of the waveguide element 120. In other embodiments, the head-mounted display device 100 may include multiple waveguide elements 120, which can be arranged according to the design. For example, the head-mounted display device 100 includes two waveguide elements 120 - the first waveguide element and the second waveguide element. Then the first waveguide element has a light input end, and the light input end includes a first diffraction structure, while the second waveguide element has a light output end, and the light output end includes a second diffraction structure.

[0025] In this embodiment, the light shielding element 130 is disposed between the projection device 110 and the light input end 122 of the waveguide element 120, and the light stop ST of the image light beam L is located between the light shielding element 130 and the waveguide element 120. Specifically, the light shielding element 130 is, for example, a solid light shielding object, such as a light shielding sheet, having a light incident port 132 for allowing the image light beam L that conforms to the size (cross-sectional area) of the light incident port 132 to pass through, thereby restricting the light flux of the image light beam L transmitted from the projection device 110 to the waveguide element 120, and blocking the redundant and divergent partial image light beam L by the light shielding element 130. In this way, the unanticipated light or light spots can be effectively reduced to avoid showing noise or ghost images in the virtual image IM (display screen), thereby improving the optical display quality of the head-mounted display device 100.

[0026] Specifically, in this embodiment, the light-shielding element 130 may be an additional physical element that is attached to the waveguide element 120 or a component between the waveguide element 120 and the projection device 110 by coating or pasting. The present invention is not limited thereto. In this embodiment, the light-shielding element 130 is directly disposed on the light inlet end 122 of the waveguide element 120. However, in other embodiments, the light-shielding element 130 may also be disposed on the light-emitting surface of the projection device 110. The present invention is not limited thereto. In this embodiment, the shape of the light inlet 132 of the light-shielding element 130 is, for example, matched to the shape of the light inlet end 122, but is not limited thereto. For example, the shape of the light inlet 132 of the light-shielding element 130 may be circular, and the shape of the light inlet end 122 may be rectangular. In addition, the light-shielding element 130 is located between the projection device 110 and the waveguide element 120. The size of the light inlet 132 is greater than or equal to the size of the aperture stop ST. The size of the light inlet end 122 is greater than or equal to the size of the aperture stop ST. In addition, in this embodiment, the size of the light inlet 132 of the light-shielding element 130 is greater than the size of the light inlet end 122, that is, the size of the light inlet 132 of the light-shielding element 130 is greater than the size of the first diffraction structure of the light inlet end 122, but is not limited thereto. In other words, the size of the light inlet 132 of the light-shielding element 130 may be equal to the size of the first diffraction structure of the light inlet end 122. In other embodiments, for example, the size of the light inlet 132 of the light-shielding element 130 is less than the size of the light inlet end 122. The present invention does not impose any restrictions. In this way, it is possible to enhance the reduction of unexpected light or light spots to avoid noise or ghosting in the virtual image. The so-called size refers to the cross-sectional area of the element.

[0027] Figure 4 is Figure 1 the optical characteristic curve graph of the head-mounted display device. Please refer to Figure 2 and Figure 4 , Figure 4 Curve 200 of 2 may represent the contrast of the virtual image IM seen by the projection target P at different sizes of the light inlet 132 of the light-shielding element 130. For example, in this embodiment, the light inlet end 122 has an area of 7 * 6 square millimeters (mm Figure 4As can be seen from the curve 200, when the size of the light incident port 132 of the light shielding element 130 gradually becomes smaller than the size of the light entrance end 122, the contrast obtained by the head-mounted display device gradually increases. Therefore, configuring the light shielding element 130 will improve the contrast of the head-mounted display device, thereby enhancing the optical resolution.

[0028] Figure 5 Schematic diagram of a head-mounted display device according to another embodiment of the present invention. Please refer to Figure 5 , the head-mounted display device 100A of this embodiment is similar to Figure 3 the head-mounted display device 100. The difference between the two is that, in this embodiment, the head-mounted display device 100A further includes a light transmission device 140, which is configured on the transmission path of the image light beam L and is located between the projection device 110 and the light entrance end 122 of the waveguide element 120. The light shielding element 130 is configured on the light entrance end 122 of the waveguide element 120. The light transmission device 140 can be any optical or non-optical element located between the projection device 110 and the waveguide element 120, and is used to transmit the image light beam L to the light entrance end 122. In this embodiment, the light transmission device 140 is an optical element, and the image light beam L is reflected by the optical element and transmitted to the waveguide element 120. For example, the light transmission device 140 is a mirror. In addition, the light shielding element 130 is located between the light transmission device 140 and the light entrance end 122. Therefore, the projection device 110 can be configured parallel to the waveguide element 120.

[0029] Figure 6 Schematic diagram of a head-mounted display device according to another embodiment of the present invention. Please refer to Figure 6 , the head-mounted display device 100B of this embodiment is similar to Figure 5 the head-mounted display device 100A. The difference between the two is that, in this embodiment, the projection device 110 is inclined relative to the waveguide element 120. In addition, the light shielding element 130 is located between the light transmission device 140 and the projection device 110, and the light shielding element 130 is provided on the light exit surface of the projection device 110.

[0030] Figure 7 Schematic diagram of a head-mounted display device according to another embodiment of the present invention. Figure 8A and Figure 8B respectively are Figure 7 the enlarged side views of area A of Figures 7 to 8B at two different viewing angles. Please refer to Figure 5The head-mounted display device 100A. The difference between the two is that in this embodiment, the light transmission device 140A is a prism, and the light-shielding element 130A is disposed on the reflection surface S of the prism. The reflection surface S can be formed by coating or is the total reflection surface of the prism. In addition, the reflection surface S of the prism further includes an anti-reflecting layer. Specifically, the light-shielding element 130A can be formed on the reflection surface S of the prism by coating or attaching, so that after the image light beam L enters the prism 140A, on the reflection surface S, part of the image light beam L is reflected by the light-incident port 132 of the light-shielding element 130A, and another part of the image light beam L is absorbed by the light-shielding element 130A, so as to achieve the effect of blocking the redundant divergent part of the image light beam L from entering the waveguide element 120.

[0031] In other embodiments, the light transmission device can further be an optical adhesive, and the projection device is fixed to the waveguide element by the optical adhesive. Or, for example, the light transmission device is a prism and can further include an optical adhesive, and the light transmission device is fixed between the projection device and the waveguide element by the optical adhesive. In other embodiments, the light transmission device can be a light-transmissive material with a refractive index not equal to 1 for transmitting the image light beam L to the waveguide element 120. However, the present invention is not limited thereto.

[0032] Figure 9 Schematic diagram of a head-mounted display device according to another embodiment of the present invention. Please refer to Figure 9 , the head-mounted display device 100D of this embodiment is similar to Figure 3 the head-mounted display device 100. The difference between the two is that in this embodiment, the head-mounted display device 100D further includes a light transmission device 140B, and the light transmission device 140B is a support structure. The light-shielding element 130 is disposed in the support structure, and the light transmission device 140B supports and fixes the light-shielding element 130. In other words, the light transmission device 140B can be a support structure of a non-optical element, so that the light-shielding element 130 can be adjusted in position in the support structure, and further the light-shielding element 130 provides a better light-shielding effect.

[0033] Figure 10 Schematic diagram of a head-mounted display device according to another embodiment of the present invention. Please refer to Figure 10 , the head-mounted display device of this embodiment is similar to Figure 3The head-mounted display device 100, the difference between the two is that, in this embodiment, the light barrier ST is located outside the projection device 110, for example, inside the waveguide element 120. Further elaborating, the light entrance end 122 is located between the light-shielding element 130 and the light barrier ST. The light entrance end 122 is used to receive the image light beam L, and the image light beam L is optically transmitted inside the waveguide element 120 and emitted from the light exit end 124 to be transmitted to the projection target P, so that the projection target P can receive the virtual image IM. In addition, in this embodiment, the light entrance end 122 of the waveguide element 120 is located between the light-shielding element 130 and the light barrier ST. The size of the light entrance 132 of the light-shielding element 130 is larger than the size of the light barrier ST. The size of the light entrance end 122 of the waveguide element 120 is larger than the size of the light barrier ST. In this way, the effect of reducing unexpected light or light spots can be enhanced.

[0034] In summary, the embodiments of the present invention have at least one of the following advantages or effects. In the head-mounted display device according to an embodiment of the present invention, since the light-shielding element is disposed between the projection device and the light entrance end of the waveguide element, the excess and divergent partial image light beams provided by the projection device can be blocked by the light-shielding element when passing through the light-shielding element. In this way, unexpected light or light spots can be effectively reduced to avoid noise or ghosting in the virtual image, thereby improving the optical display quality of the head-mounted display device.

[0035] The above are only the preferred embodiments of the present invention, and the scope of implementation of the present invention cannot be limited thereby. That is, all simple equivalent changes and modifications made according to the claims and the description of the present invention still fall within the scope covered by the patent of the present invention. In addition, any embodiment or claim of the present invention does not have to achieve all the purposes, advantages or features disclosed in the present invention. In addition, the abstract of the specification and the title of the invention are only used to assist in the retrieval of patent documents and do not limit the scope of rights of the present invention. In addition, the terms "first", "second", etc. mentioned in this specification or claims are only used to name elements or distinguish different embodiments or scopes, and do not limit the upper or lower limits of the number of elements.

[0036] Reference Numerals

[0037] 100, 100A, 100B, 100C, 100D: Head-mounted display device

[0038] 110: Projection device

[0039] 120: Waveguide element

[0040] 122: Light entrance end

[0041] 124: Light exit end

[0042] 130, 130A: Light-shielding element

[0043] 132: Light incident port

[0044] 140, 140A, 140B: Light transmission device

[0045] 200: Curve

[0046] IM: Virtual image

[0047] L: Image light beam

[0048] P: Projection target

[0049] S: Reflecting surface

[0050] ST: Diaphragm.

Claims

1. A head-mounted display device, characterized in that, The head-mounted display device includes a projection device, at least one waveguide element, and a light-shielding element, wherein: The projection device is configured to provide an image light beam. The projection device includes a lens module for transmitting the image light beam. The at least one waveguide element has a light inlet end and a light outlet end. The light inlet end is configured to receive the image light beam, and the image light beam is transmitted by the at least one waveguide element and emitted from the light outlet end. The light-shielding element is disposed between the projection device and the light inlet end of the at least one waveguide element. After the image light beam exits the projection device, a portion of the image light beam that is not blocked or absorbed by the light-shielding element converges to a light stop. The light-shielding element is located between the projection device and the light stop. The light-shielding element has a light inlet, and the size of the light inlet is greater than or equal to the size of the light stop. The light stop is located outside the projection device and the light stop is located in the at least one waveguide element.

2. The head-mounted display device according to claim 1, wherein The head-mounted display device further includes a light transmission device disposed on the transmission path of the image light beam and between the projection device and the light inlet end of the at least one waveguide element.

3. The head-mounted display device according to claim 2, wherein The light-shielding element is located between the light transmission device and the projection device.

4. The head-mounted display device according to claim 2, characterized in that The light-shielding element is located between the light transmission device and the at least one waveguide element.

5. The head-mounted display device according to claim 2, wherein The light transmission device is a reflection element, and the image light beam is reflected and transmitted to the at least one waveguide element by the reflection element.

6. The head-mounted display device according to claim 2, wherein, The light transmission device is a prism, and the light-shielding element is disposed on the reflection surface of the prism.

7. The head-mounted display device according to claim 2, wherein The light transmission device is an optical adhesive, and the projection device is fixed to the at least one waveguide element by the optical adhesive.

8. The head-mounted display device according to claim 6, wherein The light transmission device further includes an optical adhesive, and the light transmission device is fixed between the projection device and the at least one waveguide element by the optical adhesive.

9. The head-mounted display device according to claim 2, wherein The light transmission device is a support structure, the light-shielding element is disposed in the support structure, and the support structure supports and fixes the light-shielding element.

10. The head-mounted display device according to claim 1, characterized in that, The size of the light inlet end is greater than or equal to the size of the light stop.

11. The head-mounted display device according to claim 1, wherein The at least one waveguide element includes a first diffraction structure and a second diffraction structure. The first diffraction structure is located at the light inlet end, and the second diffraction structure is located at the light outlet end.

12. The head-mounted display device according to claim 1, characterized in that, The at least one waveguide element is two waveguide elements. The first waveguide element includes a first diffraction structure, and the second waveguide element includes a second diffraction structure. The first diffraction structure is located at the light inlet end of the first waveguide element, and the second diffraction structure is located at the light outlet end of the second waveguide element.

13. The head-mounted display device according to claim 1, wherein The light stop is located in the at least one waveguide element and the light inlet end is located between the light-shielding element and the light stop, or the light stop is located at the light inlet end.

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