CN108873327B - Head-mounted display device - Google Patents

Abstract

A head-mounted display device includes a display, a first waveguide element, and a second waveguide element. The image beam is projected to a projection target. The first waveguide element includes a plurality of first light splitting elements. The image light beam from the display enters the first waveguide element through the first light incident surface. The image beam converges within the first waveguide element to the first diaphragm. The image beam leaves the first waveguide element through the first light-emitting surface. The first diaphragm is located within the first waveguide element. The second waveguide element includes a plurality of second light splitting elements. The image light beam from the first waveguide element enters the second waveguide element through the second light incident surface. The image light beam leaves the second waveguide element through the second light-emitting surface and is projected to the second diaphragm outside the second waveguide element. The second diaphragm is located at the projection target.

Description

Head-mounted display device

Technical Field

The present invention relates to a display device, and more particularly, to a head-mounted display device.

Background

Near Eye Displays (NED) and Head-mounted displays (HMD) are next generation killer-grade products with great production potential. In the related application of the near-eye display technology, the technology can be divided into Augmented Reality (AR) technology and Virtual Reality (VR) technology. For augmented reality technology, related developers are currently dedicated to providing optimal image quality on the premise of lightness and thinness.

In the optical architecture of the head-mounted display for realizing augmented reality, the image light beam for display is emitted by the projection device and then enters the eyes of the user through the waveguide. The image from the light valve and the external ambient light beam enter the eyes of the user through the waveguide to achieve the effect of augmented reality. In the current head-mounted display product, because the distance between the waveguide and the optical-mechanical mechanism is too close, the environmental light beam is blocked from entering the visual field of eyes, the immersion is damaged, and the effect of enlarging the real environment is greatly reduced.

At present, the requirement for the head-mounted display device is that the design of the myopia glasses or sunglasses is closer to the general design, so how to move the bulky optical machine to the outside of the user's visual area without blocking the user's sight is one of the important issues at present. In addition, the size of the viewing angle that the head-mounted display can provide and its volume are also important factors that affect the user experience.

The background section is only used to help the understanding of the present invention, and therefore the disclosure in the background section may include some known techniques that do not constitute a part of the knowledge of those skilled in the art. The disclosure in the "background" section does not represent a representation of the disclosure or the problems that may be solved by one or more embodiments of the present invention, but is known or appreciated by those skilled in the art prior to the filing of the present application.

Disclosure of Invention

The invention provides a head-mounted display device which can provide a large viewing angle and good display quality and is small in size.

Other objects and advantages of the present invention will be further understood from the technical features disclosed in the present invention.

To achieve one or a part of or all of the above or other objects, an embodiment of the invention provides a head-mounted display device. The head-mounted display device includes a display, a first waveguide element, and a second waveguide element. The display is used for providing the image light beam. The image beam is projected to a projection target. The first waveguide element comprises a first light incident surface, a first light emitting surface and a plurality of first light splitting elements. The image light beam from the display enters the first waveguide element through the first light incident surface. The image beam converges within the first waveguide element to the first diaphragm. The image beam leaves the first waveguide element through the first light-emitting surface. The first diaphragm is located within the first waveguide element. The second waveguide element is connected to the first waveguide element. The second waveguide element comprises a second light incident surface, a second light emitting surface and a plurality of second light splitting elements. The image light beam from the first waveguide element enters the second waveguide element through the second light incident surface. The image light beam leaves the second waveguide element through the second light-emitting surface and is projected to the second diaphragm outside the second waveguide element. The second diaphragm is located at the projection target.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a schematic perspective view illustrating a head-mounted display device according to an embodiment of the invention.

Fig. 2A is a schematic side view of the head-mounted display device of fig. 1.

FIG. 2B is a schematic diagram showing a side view of a light path of the head-mounted display device in the embodiment of FIG. 2A.

FIG. 2C is a schematic side view of another head mounted display device shown in FIG. 1.

Fig. 3 is a schematic perspective view illustrating a head-mounted display device according to another embodiment of the invention.

Fig. 4 is a schematic perspective view illustrating a head-mounted display device according to another embodiment of the invention.

FIG. 5A is a schematic diagram illustrating a head mounted display device according to an embodiment of the invention.

FIG. 5B is a schematic diagram illustrating an embodiment of a head mounted display device according to the present invention.

FIG. 5C is a schematic diagram illustrating an embodiment of a head mounted display device according to the present invention.

Fig. 6A is a schematic view illustrating a head-mounted display device according to another embodiment of the invention.

Fig. 6B is a schematic view of a head-mounted display device according to another embodiment of the invention.

Fig. 7 shows a schematic top view of the second waveguide element of fig. 1.

FIG. 8 is a schematic diagram illustrating a reflectivity distribution curve of the reflectivity of the diffusion coating relative to the incident angle of the image beam according to an embodiment of the present invention.

FIG. 9 is a schematic diagram of an image frame generated by the image beam at the projection target according to the embodiment of FIG. 7.

Fig. 10 is a side view of the first waveguide element of fig. 1.

FIG. 11 is a schematic diagram illustrating an image frame generated by the image beam of the embodiment of FIG. 10 at the projection target.

Fig. 12A is a schematic diagram illustrating an image frame generated by superimposing the image beams of fig. 9 and 11 on a projection target.

Fig. 12B is a schematic diagram illustrating the reflection of the image beam to the projection target by the second beam splitter.

FIG. 13 is a schematic diagram of an image beam incident from the incident first light splitting element to the second waveguide element according to an embodiment of the invention.

Fig. 14A is a schematic diagram illustrating an image beam incident on the first light splitting element according to an embodiment of the invention.

FIG. 14B is a schematic diagram of an image beam incident on the first light splitting element according to another embodiment of the invention.

Fig. 15 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention.

Fig. 16 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention.

Fig. 17 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention.

Fig. 18 is a schematic diagram illustrating a part of elements of the head-mounted display device in the embodiment of fig. 17.

Fig. 19 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention.

Fig. 20 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention.

Fig. 21 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention.

Detailed Description

The foregoing and other features, aspects and utilities of the present general inventive concept will become apparent from the following detailed description of an embodiment thereof, which is to be read in connection with the accompanying drawings. Directional terms as referred to in the following examples, for example: up, down, left, right, front or rear, etc., are simply directions with reference to the drawings. Accordingly, the directional terminology is used for purposes of illustration and is in no way limiting.

Fig. 1 is a schematic perspective view illustrating a head-mounted display device according to an embodiment of the invention. Fig. 2A is a schematic side view of the head-mounted display device of fig. 1. Referring to fig. 1 and fig. 2A, the head-mounted display device 100 of the present embodiment includes a first waveguide element 110, a second waveguide element 120, a display 130, and a lens module 140. The second waveguide element 120 is connected to the first waveguide element 110. The lens module 140 is disposed between the display 130 and the first waveguide element 110.

In the present embodiment, it is preferred that,the first waveguide element 110 includes a first light incident surface S11, a first light emitting surface S12, and a plurality of first light splitting elements Y1, Y2, Y3, and Y4. The first light splitting elements Y1, Y2, Y3, and Y4 are arranged in the first direction Y. In the embodiment, the first light incident surface S11 is disposed opposite to the first light emitting surface S12, but the invention is not limited thereto. In an embodiment, the first light incident surface S11 may be adjacent to the first light emitting surface S12 according to different arrangement positions of the display 130. In the present embodiment, the image beam ML generates the optical effect of half-penetration and half-reflection at the positions of the first light splitting elements Y1, Y2, Y3, and Y4, and the first light splitting elements Y1, Y2, Y3, and Y4 are, for example, half-penetration and half-reflection films (STM). In the embodiment, the second waveguide element 120 includes a second light incident surface S21, a second light emitting surface S22, and a plurality of second light splitting elements X1, X2, X3, X4, X5, and X6, wherein the second light incident surface S21 and the second light emitting surface S22 belong to the same surface, and the difference is that the second light incident surface S21 of the second waveguide element 120 faces the first light emitting surface S12 of the first waveguide element 110. The second light splitting elements X1, X2, X3, X4, X5, and X6 are arranged in the second direction X. In the present embodiment, the image light beam ML generates the optical effect of half-penetration and half-reflection at the positions of the second beam splitting elements X1, X2, X3, X4, X5, and X6. In the present embodiment, the number of the light splitting elements included in each waveguide element and the spacing between adjacent light splitting elements can be designed according to different product requirements, and is not limited to the present invention. The number of the first light splitting elements and the number of the second light splitting elements can be the same or different, and the spacing between the adjacent light splitting elements can be the same or different. In the present embodiment, the display 130 is used for converting the illumination beam from the illumination system, which will be described in detail below, into the image beam ML to provide the image beam ML to the lens module 140. In the present embodiment, the display 130 includes, for example, a Digital Light Processing (DLP)^TMDLP for short^TM) But the present invention is not limited to image projection systems such as projection systems, Liquid Crystal Display (LCD) projection systems, or Liquid Crystal On Silicon (LCoS) projection systems. In the present embodiment, the lens module 140 is, for example, one or more lenses,the number is not limited and depends on the design. The lens module 140 has an optical axis a1 extending in the third direction Z. The image beam ML passes along the third direction Z in the lens module 140. The image beam ML from the display 130 passes through the lens module 140 and enters the first waveguide 110 through the first light incident surface S11. In the present embodiment, the image light beam ML passes through the first light splitting element Y1 and propagates along the first direction Y within the first waveguide element 110, and after the image light beam ML is reflected by the first light splitting element Y1, Y2, Y3, Y4, the image light beam ML exits the first waveguide element 110 through the first light emitting surface S12 along the opposite direction (-Z) of the third direction Z, it is noted that the first light splitting element Y1, Y2, Y3, Y4 is a half-penetration half-reflection film, that is, the partial image light beam ML can be reflected by the first light splitting element Y1, Y2, Y3, Y4, and the partial image light beam ML passes through the first light splitting element Y1, Y2, Y3, Y4, in the present embodiment, the light path of the main image light beam ML is taken as a description focus.

Further, the image light beam ML from the first waveguide element 110 enters the second waveguide element 120 through the second light incident surface S21 along the direction (-Z) opposite to the third direction Z, and is reflected by the reflecting surface S23 of the second waveguide element 120 and then transmitted toward the second light splitting elements X1, X2, X3, X4, X5, and X6 of the second waveguide element 120. In the present embodiment, the image light beam ML within the second waveguide element 120 is transmitted along the second direction X, and after being reflected by the second beam splitter elements X1, X2, X3, X4, X5 and X6, the image light beam ML exits the second waveguide element 110 from the second light exit surface S22 and is projected to the projection target P. Therefore, in the present embodiment, the second light incident surface S21 and the second light emitting surface S22 are the same surface of the second waveguide element 120, but the second light emitting surface S22 faces the projection target P. In the present embodiment, the projection target P is, for example, one of the eyes of the user whose pupil is one of the eyes. In other embodiments, the projection target P is an image sensing Device, such as a Charge-coupled Device (CCD) or a Complementary Metal-Oxide-Semiconductor (CMOS) image sensor, for example, which receives the image beam ML.

In the present embodiment, the image beam ML passes through the lens module 140 along a direction (-Z) opposite to the third direction Z, and the passing direction thereof is substantially the same as the extending direction of the optical axis a 1. In the present embodiment, the projection target P has a visual axis a2, and the extending direction (third direction Z) thereof is substantially the same as the transferring direction of the image light beam ML projected into the projection target P and is perpendicular to the first direction Y. Accordingly, in fig. 1, translating the visual axis a2 of the projection target P onto the YZ plane (reference plane) toward the first waveguide element 110, a reference axis A3 may be indicated in the first waveguide element 110, as shown in fig. 2A.

That is, in the present embodiment, the projection target P has a viewing axis a2 perpendicular to the first direction Y, and translation of the viewing axis a2 toward the first waveguide element 110 results in a reference axis A3 on a reference plane YZ within the first waveguide element 110. In fig. 2A, on the reference plane YZ, on the propagation path of the illumination light beam ML, the distance in the first direction between the first Stop (Stop) PA1 formed by the illumination light beam ML and the center position PC of the first light-splitting element Y1 of the first light-splitting element Y1, Y2, Y3, Y4 is D1, and the distance in the first direction Y between the reference axis A3 and the center position PC of the first light-splitting element Y1 is D2. In the present embodiment, the distance D1 is greater than or equal to the distance D2. The first light splitting element Y1 is a light splitting element that partially reflects the image light beam ML and enters the first waveguide element 110, and is also one of the first light splitting elements Y1, Y2, Y3, and Y4 closest to the lens module 140.

In the present embodiment, the image beam ML from the lens module 140 converges to the first diaphragm PA1 within the first waveguide 110. The first diaphragm PA1 is located within the first waveguide element 110. In the present embodiment, the first diaphragm PA is a position where the image light beam ML converges to the minimum beam diameter within the first waveguide element 110, and the image light beam ML starts to diverge after passing through the position of the first diaphragm PA. For example, the lens module 140 may converge the image beam ML incident to the first waveguide element 110 from the first beam splitter Y1 and reach a position where the beam diameter is minimum at the first diaphragm PA 1. After the first diaphragm PA1, the image light beam ML starts to diverge and enters the first beam splitter Y4 and is reflected to the first light exiting surface S12. In the present embodiment, the image light beam ML exits the second waveguide element 120 through the second light exiting surface S22 and then is projected outside the second waveguide element 120 to the second diaphragm PA 2. The second diaphragm PA2 is located where the target P is projected. For example, the second beam splitter elements X1, X2, X3, X4, X5, and X6 can reflect the image light beam ML incident on the second waveguide element 120 to exit the second waveguide element 120 from the second light exit surface S22, and the image light beam ML is projected to the position of the second diaphragm PA2, so that the image light beam ML can be incident on the projection target P, wherein the position of the second diaphragm PA2 is substantially the same as the position of the projection target P, i.e., the position where the image can be seen by one of the eyes of the user is the position of the second diaphragm PA 2.

In the present embodiment, the Field Of View (FOV) Of the lens module 140 corresponds to the FOV Of the image received where the target P is projected. In other words, in the present embodiment, the diagonal angle of view at which the projection target P receives the image formed by the image beam ML is substantially equal to the angle of view at which the lens module 140 projects the image beam ML. However, in other embodiments, the angle of view of the projection target P in the diagonal direction from which the image beam ML forms an image is smaller than the angle of view from which the lens module 140 projects the image beam ML.

The first viewing angle in the first direction Y and the second viewing angle in the second direction X can be obtained from the viewing angle in the diagonal direction of the image formed by the image beam ML. In the present embodiment, when the display 130 projects the image beam ML to be displayed as an image with a 16:9 projection ratio, the lens module 140 projects the image beam ML with a diagonal viewing angle between about 30 degrees and 90 degrees, for example, a viewing angle of 40 degrees, and transmits the image beam ML to the projection target P through the first waveguide element 110 and the second waveguide element 120, so that the projection target P can receive the diagonal viewing angle of the image beam ML to form an image, which is between about 30 degrees and 90 degrees, for example, 40 degrees, but is not limited thereto. One skilled in the art can calculate the first viewing angle in the first direction Y to be about 10 degrees and the second viewing angle in the second direction X to be about 17 degrees by the 16:9 projection ratio. As described above, the head-mounted display device of the present invention can make the diagonal view angle (FOV) of the image formed by the image beam ML at the projection target P30 to 90 degrees or more than 90 degrees. In addition, as shown in fig. 2A, in another embodiment, the optical axis a1 of the lens module 140 is perpendicular to the first direction Y and parallel to the visual axis a2 of the projection target P, and the diagonal view angle (FOV) of the projection target P where the image formed by the image beam ML is received may be 30-50 degrees. Referring to fig. 3, in another embodiment, the optical axis a1 of the lens module 140 is parallel to the first direction Y and perpendicular to the visual axis a2 of the projection target P, and the diagonal view angle (FOV) of the projection target P where the image formed by the image beam ML is received may be 50 to 90 degrees. The viewing angle of the diagonal direction can be designed according to different product requirements, and is not limited to the invention. The head-mounted display device 100 can provide a large viewing angle, and the volume of the head-mounted display device 100 is reduced.

In other embodiments, after the image beam ML projected by the lens module 140 forms a diagonal view angle (FOV) of the image, the size of the first view angle may be determined according to the number of the first light splitting elements in the first waveguide element 110, or according to the distance from the first light splitting element to the last light splitting element in the first waveguide element 110, or according to the distance between two adjacent light splitting elements in the first waveguide element 110. Similarly, the size of the second viewing angle is determined according to the number of the second light splitting elements in the second waveguide element 120, or according to the distance from the first light splitting element to the last light splitting element in the second waveguide element 120, or according to the distance between two adjacent light splitting elements in the second waveguide element 120, for example. It should be noted that the size of the first angle of view and the size of the second angle of view generated by the adjustment of the first waveguide device 110 and the second waveguide device 120 may be smaller than or equal to the size of the first angle of view and the size of the second angle of view of the image formed by the image beam ML projected by the lens module 140.

In addition, considering the image projection ratio provided by the display 130, the number of the first light splitting elements of the first waveguide element 110 and the number of the second light splitting elements of the second waveguide element 120 are affected, for example, if the projection ratio is 16:9, the number of the second light splitting elements of the second waveguide element 120 is greater than the number of the first light splitting elements of the first waveguide element 110. However, under other design conditions, the number of the second pieces of optical splitting elements of the second waveguide element 120 may be smaller than the number of the first pieces of optical splitting elements of the first waveguide element 110, and is not limited thereto.

In addition, according to different arrangement positions of the display and the lens module, in an embodiment, the first light incident surface of the first waveguide element may be adjacent to the first light emitting surface, and the optical axis of the lens module is parallel to the first direction. In an embodiment, the first light incident surface of the first waveguide element may be adjacent to the first light emitting surface, and the optical axis of the lens module may be perpendicular to the first direction and parallel to the second direction.

FIG. 2B is a schematic diagram showing a side view of a light path of the head-mounted display device in the embodiment of FIG. 2A. With reference to fig. 2B. Since the first light splitting elements Y1, Y2, Y3, and Y4 of the first waveguide element 110 are half-transmissive and half-reflective films, that is, part of the image light beam ML can be reflected by the first light splitting elements Y1, Y2, Y3, and Y4, and part of the image light beam ML penetrates through the first light splitting elements Y1, Y2, Y3, and Y4, in this embodiment, part of the image light beam ML converges at the position of the first light barrier PA1 in the first waveguide element 110, it can be known from the basic optical principle that the part of the image light beam ML passing through the first light splitting element Y1 can also converge at the position of the light barrier PA1 'in the second waveguide element 120, and the distance from the center position of the first light splitting element Y1 to the position of the light barrier PA 1' is equal to the distance from the center position of the first light splitting element Y1 to the position of the first light barrier PA 1. For the same reason, the partial image light beams ML reflected by the first beam splitting elements Y2 and Y3 can converge at the positions of the diaphragms PA1 "and PA1 '" in the second waveguide 120, and the distance from the center position of the first beam splitting element Y2 to the position of the diaphragm PA1 "is equal to the distance from the center position of the first beam splitting element Y2 to the position of the first diaphragm PA1, and the distance from the center position of the first beam splitting element Y3 to the position of the diaphragm PA 1'" is equal to the distance from the center position of the first beam splitting element Y3 to the position of the first diaphragm PA 1.

FIG. 2C is a schematic side view of a head mounted display device according to another embodiment of the invention. The head-mounted display apparatus of the embodiment of fig. 2C is similar to the head-mounted display apparatus 100 of the embodiment of fig. 2A, and components and related descriptions thereof may refer to components and related descriptions of the head-mounted display apparatus 100, and are not repeated herein. The differences between the head mounted display device 100 and the head mounted display device 100 are as follows. In the present embodiment, the head-mounted display device 100 includes a first optical waveguide element 110 and a second optical waveguide element 120. In addition, the head-mounted display device 100 further includes a reflector 150 disposed beside the first light incident surface S11 and facing the first light incident surface S11. The reflector 150 is used for reflecting the image light beam ML provided by the display 130 through the lens module 140, so that the image light beam ML enters the first optical waveguide element 110 from the first light incident surface S11. Then, the image beam ML entering the first optical waveguide element 110 is reflected by the plurality of first light splitters Y1, Y2, Y3, and Y4 and transmitted to the second optical waveguide element 120.

Specifically, an included angle between the reflector 150 and the first light emitting surface S11 is, for example, 45 degrees. When the image beam ML is reflected by the mirror 150, the first light splitting sheet Y1 can be incident. In addition, in the present embodiment, the position of the first diaphragm PA1 of the image light beam ML is, for example, located in the first optical waveguide element 110. The first diaphragm PA1 is located, for example, between the first light splitting sheets Y1, Y2, Y3, Y4. Therefore, the image light beam ML traveling on the first optical waveguide element 110 can be contracted to the position of the first diaphragm PA 1. In the present embodiment, by disposing the position of the first diaphragm PA1 for converging the image light beam ML inside the first optical waveguide element 110, it is able to prevent the image light beam ML from diverging too earlier on the XY plane and generating total reflection on the first light emitting surface S12 and the first light incident surface S11. That is, the image beam ML can be guided into the second optical waveguide device 120 through the first light splitting sheets Y1, Y2, Y3, and Y4 before the image beam ML is totally reflected, so that the problem of unexpected display caused by the total reflection of the image beam ML in the first optical waveguide device 110 can be avoided.

Fig. 3 is a schematic perspective view illustrating a head-mounted display device according to another embodiment of the invention. Referring to fig. 1 and fig. 3, the head-mounted display device 200 of the present embodiment is similar to the head-mounted display device 100 of the embodiment of fig. 1, but the main difference between the two devices is, for example, that the display 230 and the lens module 240 of the head-mounted display device 200 are disposed parallel to the side of the first waveguide 110, and the image light beam ML from the lens module 240 enters the first waveguide 100 from the first light incident surface S13 of the first waveguide 110 and exits the first waveguide 110 through the first light exiting surface S12. Therefore, in the present embodiment, the first light incident surface S13 of the first waveguide element 110 is adjacent to the first light emitting surface S12, and the optical axis a1 of the lens module 240 is parallel to the first direction Y. In the present embodiment, the first diaphragm PA1 is located inside the first waveguide element 210, and the second diaphragm PA2 is located where the target P is projected. Also, the position of the first diaphragm PA1 within the first waveguide element 210 also satisfies the condition that the distance D1 is greater than or equal to the distance D2.

Fig. 4 is a schematic perspective view illustrating a head-mounted display device according to another embodiment of the invention. Referring to fig. 1 and fig. 4, the head-mounted display device 800 of the present embodiment is similar to the head-mounted display device 100 of the embodiment of fig. 1, but the main difference between the two is that the first light incident surface is adjacent to the first light emitting surface, and the optical axis a1 of the lens module is perpendicular to the first direction Y and parallel to the second direction X.

Specifically, in the present embodiment, the head-mounted display apparatus 800 includes a first waveguide element 810, a second waveguide element 820, a third waveguide element 850, a display 830, and a lens module 840. In one embodiment, the third waveguide element 850 and the second waveguide element 820 may also be made of the same material and integrally formed. The display 830 is used to provide the image beam ML. In the present embodiment, the image light beam ML is incident on the first waveguide element 810 via the first incident surface S14, and is reflected by the reflecting surface S15 and propagates in the first direction Y. Then, the image light beam ML exits the first waveguide 810 through the first light exiting surface S12. Therefore, in the present embodiment, the first light incident surface S14 and the first light emitting surface S12 are adjacent to the reflecting surface S15, and the optical axis a1 of the lens module 840 is perpendicular to the first direction Y and parallel to the second direction X. The positions of the display 830 and the lens module 840 may be determined according to different product designs or optical characteristics, and the invention is not limited thereto. Furthermore, the third waveguide 850 of the present embodiment may adopt a third waveguide design as in one of the embodiments of fig. 5A to 5C.

In the present embodiment, the first waveguide element 810 includes a plurality of first light splitting elements 811. The image beam ML generates an optical effect of half-penetration and half-reflection at the position of the first light splitting elements 811, and is incident on the third waveguide element 850. The third waveguide element 850 may have a reflective structure, such as described in the embodiments of fig. 5A-5C. In the present embodiment, the image light beam ML is reflected at the position of the reflection structure of the third waveguide element 850 and is incident to the second waveguide element 820. The second waveguide element 820 includes a plurality of second light splitting elements 831. The image light beam ML undergoes the optical effect of half-penetration and half-reflection at the positions of these second light splitting elements 831 and exits the second waveguide element 820. In the present embodiment, the image beam ML exiting from the second waveguide 820 is used to enter the projection target P, wherein the projection target P is, for example, an eye position of a user. In addition, the number of the first light splitting element 811 and the second light splitting element 831 is not limited to that shown in fig. 4, and the number of the light splitting elements disposed in the first waveguide 810 and the second waveguide 820 may be designed according to different product requirements, and the invention is not limited thereto.

In the present embodiment, the first light splitting elements 811 and the second light splitting elements 831 respectively have a coating film, and the coating film can only allow the image beam ML incident at a specific incident angle range to pass through. Therefore, when the image light beam ML enters the first light splitting elements 811 and the second light splitting elements 831 at an excessive incident angle during the traveling process of the first waveguide 810 and the second waveguide 820, a part of the image light beam ML is reflected on the first light splitting elements 811 and the second light splitting elements 831. The undesired reflected image beam ML continues to travel through the first waveguide 810 and the second waveguide 820, and is then obliquely directed into the user's eye in a direction opposite to the desired direction when the beam splitter is subsequently incident at a smaller angle. In this case, the user can view not only the originally intended image but also an unintended image that is a mirror image. Therefore, the user can easily feel the existence of ghost images or the blurring of the image during the use of the head-mounted display.

Fig. 5A is a schematic diagram of a head-mounted display device according to an embodiment of the invention, referring to fig. 5A. In the present embodiment, the head-mounted display device 500 includes a first waveguide element 510, a second waveguide element 520, and a third waveguide element 530, wherein the second waveguide element 520 includes a plurality of second light splitting elements 531. In the present embodiment, the first waveguide element 510 is disposed beside the third waveguide element 530. The first waveguide element 510 may be bonded to the third waveguide element 530, or bonded through a transparent adhesive, or fixed to the peripheries of the first waveguide element 510 and the third waveguide element 530 by a fixing member 532 (e.g., a spacer, an adhesive, or a spacer), and the middle region has a gap (gap), which may be a small air gap (air gap). In addition, the first light emitting surface ES1 faces the second light incident surface IS 2. The second light incident surface IS2 IS connected to the second light emitting surface ES 2. The third waveguide element 530 can be attached to the second waveguide element 520 or bonded through a transparent adhesive. Therefore, the third light incident surface IS3 IS connected to the second light emitting surface ES 2. In the present embodiment, the third waveguide element 530 includes a reflective structure 521. The reflective structure 521 may be composed of a plurality of optical microstructures, and the plurality of optical microstructures may be a plurality of reflective surfaces arranged obliquely and periodically.

In addition, the purpose of the air gap (air gap) is to inject the image beam ML having a large incident angle into the first waveguide 510, so that a part of the image beam ML can be prevented from directly penetrating the first waveguide 510, and the part of the image beam ML can be transmitted in the first waveguide 510 by total reflection. Another advantage IS that the partial image beam ML IS reflected by the reflective structure 521 and then directed to the second light incident surface IS2, and the air gap can make the partial image beam ML generate total reflection at the second light incident surface IS2, so as to guide the partial image beam ML into the second waveguide element 520.

In the present embodiment, the image light beam ML enters the third waveguide 530 through the first light emitting surface ES1 of the first waveguide 510, and enters the third waveguide 530 through the second light incident surface IS 2. The image light beam ML reflects the image light beam ML from the second light incident surface IS2 through the reflective structure 521, and exits the third waveguide 530 through the second light emitting surface ES 2. The image light beam ML enters the second waveguide 520 through the third light incident surface IS3 and exits the second waveguide 520 through the third light exiting surface ES 3.

In the present embodiment, the third waveguide element 530 and the second waveguide element 520 may be different materials. For example, the third waveguide 530 may be a plastic material, and the first waveguide 510 and the second waveguide 520 may be glass, but the invention is not limited thereto. In one embodiment, the third waveguide 530 and the second waveguide 520 may be made of the same material and integrally formed. In the present embodiment, the material selection of the first waveguide 510, the third waveguide 530 and the second waveguide 520 may also be determined according to different reflectivity requirements or product designs.

Fig. 5B is a schematic diagram of a head-mounted display device according to an embodiment of the invention, referring to fig. 5B. In the embodiment, the head-mounted display device 600 includes a first waveguide element 610, a third waveguide element 630 and a second waveguide element 620, wherein the second waveguide element 620 includes a plurality of second light splitting elements 631. In the present embodiment, the first waveguide element 610 is disposed beside the second waveguide element 620. The first waveguide element 610 may be attached to the second waveguide element 620, or bonded through a transparent adhesive, or fixed at the periphery of the first waveguide element 610 and the second waveguide element 620 by using a mechanical member (e.g., a spacer or an adhesive), but the middle region has a gap, which may be a small air gap. Therefore, on the transmission path of the image light beam ML, the image light beam ML passes through the second waveguide 620 via the first light emitting surface ES1 and is transmitted to the third waveguide 630. In addition, the first light emitting surface ES1 faces the second light incident surface IS 2. The second light incident surface IS2 IS connected to the second light emitting surface ES 2. The third waveguide element 630 can be bonded to the second waveguide element 620 or bonded through a transparent adhesive. Therefore, the third light incident surface IS3 IS connected to the second light emitting surface ES 2. The second light incident surface IS2 and the third light incident surface IS3 face the first light emitting surface ES 1. In the present embodiment, the third waveguide element 630 includes a reflective structure 621. The reflective structure 621 may be composed of a plurality of optical microstructures, and the plurality of optical microstructures may be a plurality of reflective surfaces arranged obliquely and periodically.

In the present embodiment, the image light beam ML enters the second waveguide 620 through the first light emitting surface ES1 of the first waveguide 610, passes through the second waveguide 620, and enters the third waveguide 630 through the second light incident surface IS 2. The image light beam ML reflects the image light beam ML from the second light incident surface IS2 through the reflective structure 621, and exits the third waveguide 630 through the second light emitting surface ES 2. The image light beam ML enters the second waveguide 620 through the third light incident surface IS3 and exits the second waveguide 620 through the third light exiting surface ES 3.

In the present embodiment, the third waveguide element 630 and the second waveguide element 620 may be different materials. For example, the third waveguide element 630 may be a plastic material, and the first waveguide element 610 and the second waveguide element 620 may be glass, but the invention is not limited thereto. In one embodiment, the third waveguide element 630 and the second waveguide element 620 may also be made of the same material and integrally formed. In the present embodiment, the material selection of the first waveguide element 610, the third waveguide element 630 and the second waveguide element 620 can also be determined according to different reflectivity requirements or product designs.

Fig. 5C is a schematic diagram of a head-mounted display device according to an embodiment of the invention, referring to fig. 5C. In the embodiment, the head-mounted display device 700 includes a first waveguide 710, a third waveguide 730, and a second waveguide 720, wherein the second waveguide 720 includes a plurality of second light splitting elements 731. In the present embodiment, the first waveguide element 710 is disposed beside the second waveguide element 720. The first waveguide element 710 may be attached to the second waveguide element 720, or bonded through a transparent adhesive, or fixed by a fixing member (e.g., a spacer or an adhesive or a spacer, as shown in fig. 5A) at the periphery of the first waveguide element 710 and the second waveguide element 720, and the middle region has a gap (gap), which may be a small air gap (air gap). Therefore, the first light emitting surface ES1 faces the second light incident surface IS2 through the second waveguide 720. The second light incident surface IS2 IS connected to the second light emitting surface ES 2. The third waveguide 730 IS obliquely disposed beside the second waveguide 720, so that the second light incident surface IS2, the second light emitting surface ES2 and the third light incident surface IS3 have an oblique angle with respect to the third light emitting surface ES 3. The third waveguide assembly 730 can be bonded to the second waveguide assembly 720 or bonded through a transparent adhesive. Therefore, the third light incident surface IS3 IS connected to the second light emitting surface ES 2. In the present embodiment, the third waveguide element 730 includes a reflective structure 721 and a transparent layer. The third waveguide 730 is a reflecting unit (reflecting unit), and the reflecting structure 721 can be a mirror or a reflective coating.

In the embodiment, the image light beam ML enters the second waveguide 720 through the first light emitting surface ES1 of the first waveguide 710, passes through the second waveguide 720, and enters the third waveguide 730 through the second light incident surface IS 2. The image light beam ML reflects the image light beam ML from the second light incident surface IS2 through the reflective structure 721, and exits the third waveguide 730 through the second light exiting surface ES 2. The image light beam ML enters the second waveguide 720 through the third light incident surface IS3 and exits the second waveguide 720 through the third light exiting surface ES 3.

In the present embodiment, the first waveguide 710, the third waveguide 730 and the second waveguide 720 may all be made of glass material, but the invention is not limited thereto. In one embodiment, the third waveguide 730 can be a reflective unit made of plastic material. Moreover, the material selection of the first waveguide 710, the third waveguide 730 and the third waveguide 730 can be determined according to different reflectivity requirements or product designs.

Fig. 6A is a schematic view illustrating a head-mounted display device according to another embodiment of the invention. Referring to fig. 1 to 4 and 6A, in the present embodiment, the head-mounted display device 900 includes a first waveguide 910, a third waveguide 930, a second waveguide 920 and a reflective element 950. The reflective element 950 is used for receiving the image beam ML provided by the display, the reflective element 950 may be a prism (not shown) having a reflective layer, and the image beam provided by the display is incident on the reflective element 950 from the X-axis direction and is incident on the first waveguide 910 from the Y-axis direction through the reflective layer of the reflective element 950. For convenience of illustration, the third waveguide element 930 of the present embodiment is designed by using the reflection structure of the second waveguide element in the embodiment of fig. 5C, but the present invention is not limited thereto. The reflective structure design of the second waveguide device in the embodiments of fig. 5A and 5B can also be applied.

In the present embodiment, the present invention proposes that the image beam ML provided by the display device can have only a single polarization direction. For example, when the image light beam ML is incident on the first waveguide 910 from the reflecting element 950, a polarizing element (Polarizer) may be used, the polarizing element 960 may be disposed between the display and the first waveguide 910, between the display and the reflecting element 950, or between the reflecting element 950 and the first waveguide 910, so that the image light beam incident on the first waveguide 910 from the display only has light in the P-polarization direction (as in the direction of the third axis Z), and the image light beam ML is incident on the second waveguide 920 from the first waveguide 910 via the reflecting structure of the third waveguide 930, and the light in the P-polarization direction is converted into light in the S-polarization direction (as in the direction of the second axis Y) based on the optical definition of the basic polarized light in this field. Therefore, the first waveguide 910 only transmits the image beam with a single polarization direction, and the coating layers of the first beam splitter 911 and the second beam splitter 931 can be designed corresponding to the image beam with a single polarization direction.

In another embodiment, the head-mounted display device 900 of the present embodiment may further include a phase retarder 970. In this embodiment, the polarization element 960 may be disposed between the display and the first waveguide 910, or between the reflection element 950 and the first waveguide 910, so that the image beam incident from the reflection element 950 to the first waveguide 910 may only have light in the S-polarization direction. The phase retarder 970 may be disposed between the first waveguide 910 and the third waveguide 930 (the phase retarder 970 may also be disposed between the second waveguide 920 and the first waveguide 910) so that the image beam incident on the second waveguide 920 from the first waveguide 910 may be light in the S-polarization direction. Accordingly, the head-mounted display device 900 can effectively reduce the undesired traveling of the reflected light in the first waveguide 910 and the second waveguide 920 by configuring the polarization element 960 and the phase retarder 970.

Fig. 6B is a schematic diagram of a head-mounted 900A display device according to another embodiment of the invention. In this regard, the image beam ML provided by the display 830 may have only a single polarization direction. For example, the image beam ML directly incident on the first waveguide 910 may have P-polarization light (as in the third direction Z), and the image beam ML is naturally converted into S-polarization image beam ML (as in the first direction Y) by the reflection structure incident on the second waveguide 920 from the first waveguide 910 based on the basic optical reflection effect. Therefore, the first waveguide 910 can only transmit the image beam ML with a single polarization direction, and the respective coatings of the first light splitting element 911 and the second light splitting element 931 can be designed corresponding to the image beam ML with a single polarization direction. Accordingly, the head-mounted display device 900A of the present embodiment can effectively reduce the unexpected situation that the reflected light travels in the first waveguide element 910 and the second waveguide element 920. In the present embodiment, the first diaphragm is also located inside the first waveguide element 910, and the second diaphragm PA2 is located where the target P is projected. Also, the position of the first diaphragm within the first waveguide element 910 also satisfies the condition that the distance D1 is greater than or equal to the distance D2.

Fig. 7 shows a schematic top view of the second waveguide element of fig. 1. FIG. 8 is a schematic diagram illustrating a reflectivity distribution curve of the reflectivity of the diffusion coating relative to the incident angle of the image beam according to an embodiment of the present invention. In fig. 8, the reflectance distribution curve of the reflectance of the diffusion coating film with respect to the incident angle of the image beam is, for example, a wavelength of 520 nm, but the invention is not limited thereto. The reflectance distribution curve of fig. 8 is for illustration only and is not intended to limit the present invention. Referring to fig. 7 to 8, in the present embodiment, each of the second light splitting elements X1, X2, X3, X4, X5, and X6 in the second waveguide element 120 includes a first surface and a second surface opposite to the first surface, and one of the first surface and the second surface may include a diffusion coating, for example, the first surface includes a diffusion coating. Taking the second beam splitting element X1 as an example, the second surface SX12 is opposite to the first surface SX11, and the first surface SX11 includes a diffusion coating film. In the present embodiment, the image light beam ML enters each second light splitting element from the first surface of each second light splitting element, and the incident angle of the image light beam ML entering each second light splitting element ranges from 15 degrees to 45 degrees, so that a part of the image light beam ML can be reflected to the pupil P through the diffusion coating, wherein an included angle between each second light splitting element in the second waveguide element 120 and the second light emitting surface S22 is 30 degrees, but the disclosure is not limited thereto. In the second waveguide element 120, the image beam ML has a polarization direction of a second polarization direction (e.g., S-direction polarized light). In the present embodiment, the reflectance of the diffusion coating film conforms to the reflectance distribution curve of fig. 8, for example. The reflectivity of the Nth second light splitting element is less than or equal to the reflectivity of the (N +1) th second light splitting element when the incident angle is between 15 and 45 degrees, wherein N is an integer greater than or equal to 1. In fig. 8, a curve SR (N +1) is, for example, a reflectance distribution curve of the (N +1) th second light splitting element, and a curve SRN is, for example, a reflectance distribution curve of the nth second light splitting element. For example, the reflectivity of the 1 st second light splitting element X1 is less than or equal to the reflectivity of the 2 nd second light splitting element X2, but not limited thereto.

FIG. 9 is a schematic diagram of an image frame generated by the image beam at the projection target according to the embodiment of FIG. 7. Referring to fig. 7 to 9, in the present embodiment, the image frame formed in the projection target P is the image beam ML reflected from each second beam splitting element, in other words, the image frame in the horizontal direction (the second direction X) visible to human eyes. Therefore, the image frames generated on the projection target P by the image beam ML reflected by the different second beam splitting elements overlap or are partially connected, and if a gap is generated between the image frames, an image having a black area is observed by human eyes. Therefore, as shown in fig. 9, for example, different areas of the image frame in the projection target P are contributed by the image beams ML reflected by different second beam splitters, and image overlapping or image connection is generated in partial areas. According to the design of the diffusion coating of the present embodiment, that is, the reflectivity of the nth second light splitting element of the second light splitting elements is less than or equal to the (N +1) th second light splitting element of the second light splitting elements, even if some blocks are overlapped, the image frame in the projection target P can be kept uniform, and has good display quality.

Fig. 10 is a side view of the first waveguide element of fig. 1. Referring to fig. 10, in the present embodiment, each of the first light splitting elements Y1, Y2, Y3, and Y4 includes a first surface and a second surface opposite to the first surface, and the first surface includes a diffusion coating. One of the first surface and the second surface may include a diffusion coating, for example, the first light splitting element Y1, the second surface SY22 is opposite to the first surface SY21, and the first surface SY21 includes a diffusion coating. In the embodiment, referring to fig. 3, the optical axis a1 of the lens module 140 is parallel to the first direction Y and perpendicular to the viewing axis a2 of the projection target P, the image light beam ML enters the first surface SY21 of the first light splitting element Y1 at an incident angle of 30 degrees to 60 degrees, wherein an included angle between each first light splitting element in the first waveguide element 110 and the first light emitting surface S12 is 45 degrees, and may be 30 degrees in other designs, but the disclosure is not limited thereto. In addition, the reflectivity of the mth first light splitting element is less than or equal to the reflectivity of the (M +1) th first light splitting element, where M is an integer greater than or equal to 1. For example, the reflectivity of the 2 nd first beam splitter Y2 is less than or equal to the reflectivity of the 3 rd first beam splitter Y3, so that part of the image beam ML can be reflected to the second waveguide device 120 through the diffusion coating, and the image frame in the projection target P can be kept uniform, thereby having good display quality. In another embodiment, referring to fig. 2A simultaneously, the optical axis a1 of the lens module 140 is perpendicular to the first direction Y and parallel to the visual axis a2 of the projection target P, the image light beam ML is incident on the first surface SY21 of the first light splitting element, 1 minus the reflectivity of the first light splitting element is less than or equal to the reflectivity of the (M +1) th first light splitting element, where M is an integer greater than or equal to 1. For example, the reflectivity of the 1 st first light splitting element Y1 subtracted by 1 is less than or equal to the reflectivity of the 2 nd first light splitting element Y2. Thus, a portion of the image beam ML is reflected to the second waveguide device 120 through the diffusion coating, and the image frame in the projection target P can be kept uniform, thereby having good display quality.

FIG. 11 is a schematic diagram illustrating an image frame generated by the image beam of the embodiment of FIG. 10 at the projection target. Referring to fig. 10 and 11, in the present embodiment, the image picture formed in the projection target P is the image beam ML reflected from each first light splitting element. In other words, the human eye can see the image screen in the vertical direction (the first direction Y). The image beams ML reflected by different first beam splitting elements partially overlap or partially overlap each other, that is, the image beams ML reflected by different second beam splitting elements generate an image on the projection target P, the image is formed by the partially overlapped image beams ML, or the image beams ML reflected by different second beam splitting elements generate an image on the projection target P, and the image is formed by the partially connected image beams ML.

In other embodiments, the image beam ML reflected by the different first beam splitter and the image beam ML reflected by the different second beam splitter generate an image frame on the projection target P, and the image frame is formed by partially overlapping the image beams ML. Or in another embodiment, the image beam ML reflected by the different first light splitting elements and the image beam ML reflected by the different second light splitting elements generate an image frame on the projection target P, wherein the image frame is formed by partial connected image beams. If a gap is generated between the image frames, the human eyes can see an image with a black area. Therefore, as shown in fig. 11, different areas of the image frame in the projection target P are contributed by the image beams ML reflected by different first beam splitters, and image overlapping or image connection occurs in a portion of the areas, so that the image frame in the projection target P can be kept uniform and has good display quality.

Fig. 12A is a schematic diagram illustrating an image frame generated by superimposing the image beams of fig. 9 and 11 on a projection target. As can be seen from fig. 9, 11 and 12A, the image picture formed in the projection target P is the image beam ML reflected from each second beam splitter to form an image picture in the horizontal direction (second direction X), and the image picture formed in the projection target P is the image beam ML reflected from each first beam splitter to form an image picture in the vertical direction (first direction Y). The image frames of the two are overlapped to form the image frame which can be seen by the projection target P.

Fig. 12B is a schematic diagram illustrating the reflection of the image beam to the projection target by the second beam splitter. Referring to fig. 12B, the image beam is emitted to the outside of the second waveguide element in a diffused manner through the second light splitting element, but the image beam projected by the second light splitting element can be received at the position of the projection target P, and the projection target P receives the partially overlapped image beam or the partially adjacent image beam, so that the projection target P can obtain a clear and complete image.

FIG. 13 is a schematic diagram of an image beam incident from the incident first light splitting element to the second waveguide element according to an embodiment of the invention. In fig. 13, the incident angles of the image beam ML reflected by the different first light splitting elements from the first waveguide element 110 to the second waveguide element 120 may be different, and therefore, the diffusion coatings may be designed differently for the different first light splitting elements. The path of the principal ray of the partial image beam reflected by the first light splitting element Y1 of the first light splitting element is deflected to the last light splitting element Y4 of the first light splitting element. The path of the principal ray of the partial image beam reflected by the last light-splitting element Y4 of the first light-splitting element is deflected to the first light-splitting element Y1 of the first light-splitting element. The beam direction in fig. 13 is schematically illustrated, and the actual image beam is incident into the second waveguide element 120. For example, in fig. 13, the traveling direction (the first direction Y) of the image light beam ML is, for example, at an angle of 45 degrees with respect to the first light splitting element as an incident angle, and the angle of the image light beam ML incident on the first light splitting element may be greater than, less than or equal to 45 degrees (a reference angle). For example, the angle at which the image beam ML is incident on the first beam splitter Y1, Y2 may be greater than 45 degrees, as shown in fig. 14A. Fig. 14A is a schematic diagram illustrating the image light beam ML entering the first light splitting element Y1, wherein the incident angle is greater than 45 degrees. The angle at which the image light beam ML is incident on the first light splitting element Y2 can be analogized. Therefore, the diffusion coating design for the first light splitting elements Y1 and Y2 can be designed to have the reflectivities of 15% and 30% in the regions where the incident angles are greater than 45 degrees and the incident angles are 47 degrees and 50 degrees for the first light splitting elements Y1 and Y2, so that the image beam ML reflected from the first light splitting elements Y1 and Y2 to the second waveguide element 120 has a larger light quantity, thereby improving the efficiency of projecting the image beam ML to the projection target P. For another example, the angle at which the image beam ML is incident on the first beam splitter Y3, Y4 may be less than 45 degrees, as shown in fig. 14B. Fig. 14B is a schematic diagram illustrating the image light beam ML entering the first light splitting element Y4, wherein the incident angle is smaller than 45 degrees. The angle at which the image light beam ML is incident on the first light splitting element Y3 can be analogized. Therefore, the diffusion coating design for the first light splitting elements Y3 and Y4 can be designed to have the reflectivities of 40% and 55% in the regions where the incident angles are less than 45 degrees and the incident angles are 40 degrees and 43 degrees in the first light splitting elements Y3 and Y4, so that the image beam ML reflected from the first light splitting elements Y3 and Y4 to the second waveguide element 120 has a larger light quantity, thereby improving the efficiency of projecting the image beam ML to the projection target P.

Therefore, in the embodiment of the present invention, by adjusting the optical characteristics of the diffusion coating on the beam splitter, the image frame on the projection target P has uniformity and the light amount of the image beam ML projected to the projection target P is large.

In the following, a method of operating a head-mounted display device comprising an illumination system, a display and a waveguide system is described.

Fig. 15 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention. Referring to fig. 15, the head-mounted display device 300A of the present embodiment includes an illumination system 350A, a display 330A, a lens module 340 and a waveguide system. The lens module 340 may include one or more lenses and the waveguide system includes a first waveguide element 310 and a second waveguide element 320. In the present embodiment, the display 330A includes, for example, a Digital Light Processing (DIGITAL LIGHT PROCESSING)^TMDLP for short^TM) A projection system for converting the illumination beam IL from the illumination system 350A into an image beam ML. The image beam ML is delivered to the projection target P via the waveguide system. In the present embodiment, the waveguide system can be operated from fig. 1 to fig. 14B are described in sufficient detail to enable a full teaching, suggestion, and description.

In this embodiment, illumination system 350A is configured to provide an illumination beam IL to display 330A. Illumination system 350A includes illumination source 351, collimating lens group 353, aperture stop 355, light homogenizing element 357, and prism module 359A. The illumination source 351 provides an illumination beam IL. Illumination beam IL passes through collimating lens group 353, aperture stop 355, light homogenizing element 357, and prism module 359A to display 330A. In the present embodiment, the aperture stop 355 is disposed between the collimating lens assembly 353 and the light equalizing element 357, and the illumination source 351 is, for example, a Light Emitting Diode (LED), but not limited thereto, the light equalizing element 357 is, for example, a lens array (fly-eye lens array), and the collimating lens assembly 353 includes one or more lenses. In the present embodiment, illumination beam IL from illumination source 351 converges within illumination system 350A to a third stop (stop) PA 3. A third diaphragm PA3 is located at the aperture diaphragm 355. In this embodiment, the aperture stop 355 may have a driving element 358 (e.g., a motor) for controlling the opening size of the aperture stop 355 to control the area size of the third stop PA 3. Thus, the aperture stop 355 can adjust the amount of illumination beam IL passing through its opening. In the present embodiment, the prism module 359A includes a prism 352 (first prism). Illumination beam IL from light homogenizing element 357 is passed to display 330A via prism 352. In another embodiment, the opening of the aperture stop 355 may be a fixed aperture size, depending on design requirements.

Fig. 16 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention. Referring to fig. 15 and 16, the head-mounted display device 300B of the present embodiment is similar to the head-mounted display device 300A of fig. 15, but the main difference between the two devices is, for example, the design of the illumination system 350B and the display 330B.

Specifically, in the present embodiment, the display 330A includes, for example, a Liquid Crystal On Silicon (LCoS) projection system for converting the illumination beam IL from the illumination system 350B into the image beam ML. The image beam ML is delivered to the projection target P via the waveguide system. In this embodiment, the operation of the waveguide system can be sufficiently taught, suggested and embodied from the description of the embodiment of fig. 1-14B. In this embodiment, illumination system 350B is configured to provide an illumination beam IL to display 330B. The aperture stop 355 is disposed between the collimating lens group 353 and the light equalizing element 357. In the present embodiment, the illumination beam IL from the illumination source 351 converges within the illumination system 350A to the third diaphragm PA 3. The illumination beam IL from the illumination source 351 may be polarity converted to an illumination beam IL having a single polarity. A third diaphragm PA3 is located at the aperture diaphragm 355. In this embodiment, the aperture stop 355 has a driving element. The driving element is used to control the opening size of the aperture stop 355 to control the area size of the third stop PA 3. Thus, the aperture stop 355 can adjust the amount of illumination beam IL passing through its opening. In this embodiment, the prism module 359B includes a Polarizing Beam Splitter (PBS). Illumination beam IL from light homogenizing element 357 is passed to display 330A via polarizing beam splitter and reflected to lens module 340.

Fig. 17 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention. Referring to fig. 15 and 17, the head mounted display device 300C of the present embodiment is similar to the head mounted display device 300A of fig. 15, but the main difference between the two devices is, for example, the design manner of the prism module 359C.

Specifically, in the present embodiment, the display 330C includes, for example, a Digital Light Processing (Digital Light Processing)^TMDLP for short^TM) A projection system for converting the illumination beam IL from the illumination system 350C into an image beam ML. The image beam ML is delivered to the projection target P via the waveguide system. In this embodiment, the operation of the waveguide system can be sufficiently taught, suggested and embodied from the description of the embodiment of fig. 1-14B. In the present embodiment, the prism module 359C includes a first prism 359_1, a second prism 359_2, and a third prism 359_ 3. The first prism 359_1 has a curved surface. The curved surface has a reflective layer R. The curved surface is used to reflect the illumination beam IL from the light equalizing element 357. In this embodiment, air is slightly spaced between two prismsA gap. For example, a first gap is located between the first prism 359_1 and the second prism 359_2, and a second gap is located between the second prism 359_2 and the third prism 359_ 3. The illumination beam IL from the light homogenizing element 357 is delivered to the display 330C via the first prism 359_1, the first gap, the curved surface, the second prism 359_2, the second gap, and the third prism 359_ 3. In one embodiment, the first prism 359_1 can be attached to the second prism 359_2 or bonded through a transparent adhesive. The second prism 359_2 can be attached to the third prism 359_3 or bonded through a transparent adhesive.

In the embodiment of fig. 15 to 17, the illumination systems 350A, 350B, 350C have the first F value, and the first F value is determined according to the area size of the third diaphragm PA 3. The lens module 340 has a second F-number. The head-mounted display devices 300A, 300B, and 300C meet the condition that the first F value is greater than or equal to the second F value, so that the reduction of the ghost image generated in the image frame can be eliminated. The F value may be defined as 1/2 × sin (θ), and the θ angle is the cone angle (cone angle) at which the light beam is incident.

For example, fig. 18 is a schematic diagram illustrating a part of elements of the head-mounted display device in the embodiment of fig. 17. For the sake of simplicity, fig. 18 only shows the display 330C, the third prism 359_3, and the lens module 340 of the head mounted display device 300C. In the present embodiment, the illumination beam IL is incident on the display 330C, and the display 330C includes, for example, a Digital Micromirror Device (DMD). The DMD first converts the illumination beam IL into an image beam ML, and then reflects the image beam ML to the third prism 359_ 3. The third prism 359_3 reflects the image beam ML to the lens module 340. In the present embodiment, the cone angle (cone angle) of the illumination beam IL incident on the display 330C is, for example, θ 1, and the first F value of the illumination system 350C can be defined as 1/2 × sin (θ 1). In the present embodiment, the lens module 340 receives the image beam ML from the display 330C, and the cone angle (cone angle) thereof is θ 2, for example. The second F value of the lens module 340 may be defined as 1/2 × sin (θ 2).

In the present embodiment, the required incident angle θ 2 can be obtained by presetting the second F value of the lens module 340 according to the design of the manufacturer, so that the size of the third diaphragm PA3 can be controlled by adjusting the size of the opening through the aperture diaphragm 355, and the size of the third diaphragm PA3 affects the size of the cone angle θ 1 of the illumination beam IL incident on the display 330C. That is, after the second F value of the lens module 340 is determined, the size of the first F value of the illumination system 350C can be controlled by the aperture stop 355, so that the head-mounted display device 300C meets the condition that the first F value is greater than or equal to the second F value. In one embodiment, the opening of the aperture stop 355 may be a fixed aperture size, and the first F value of the control illumination system 350C is designed to be larger than or equal to the second F value in cooperation with the second F value design of the lens module 340. In the embodiments of fig. 15 and 16, the illumination systems 350A and 350B may also be adjusted in this way, so that the head-mounted display devices 300A and 300B meet the condition that the first F value is greater than or equal to the second F value, and therefore, it is easy for a user to eliminate or reduce the occurrence of ghost images in the viewed image or blur the viewed image during the use of the head-mounted displays 300A and 300B.

Fig. 19 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention. Referring to fig. 15 and fig. 19, the head-mounted display apparatus 400A of the present embodiment is similar to the head-mounted display apparatus 300A of fig. 15, but the two are mainly different from each other in, for example, the arrangement position of the aperture stop 455 and the light equalizing element 457 is a light integrating rod.

Specifically, in the present embodiment, the prism module 459A includes a prism and two lenses, wherein the aperture stop 455 is disposed between the two lenses, and the light equalizing element 457 is, for example, a light integrating rod. In the present embodiment, the illumination beam IL from the illumination source 451 converges within the illumination system 450A to the third diaphragm PA 3. A third diaphragm PA3 is located at the aperture diaphragm 455. In this embodiment, the aperture stop 455 has a driving element. The driving elements are used to control the size of the opening of the aperture stop 455 to control the size of the third stop PA3 and thus the size of the cone angle at which the illumination beam IL is incident on the display 430A. Therefore, after the second F value of the lens module 440 is determined, the size of the first F value of the illumination system 450A can be controlled by the aperture stop 455, so that the head-mounted display device 400A meets the condition that the first F value is greater than or equal to the second F value.

Fig. 20 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention. Referring to fig. 16 and 20, the head-mounted display apparatus 400B of the present embodiment is similar to the head-mounted display apparatus 300B of fig. 16, except that the two are mainly different from each other in, for example, the arrangement position of the aperture stop 455 and the light-equalizing element 457 is a light integrating rod.

Specifically, in the present embodiment, the prism module 459B includes two prisms and two lenses, wherein the aperture stop 455 is disposed between the two lenses in the prism module 459B, and the light equalizing element 457 is, for example, a light integrating rod. In the present embodiment, the illumination beam IL from the illumination source 451 converges within the illumination system 450A to the third diaphragm PA 3. A third diaphragm PA3 is located at the aperture diaphragm 455. In this embodiment, the aperture stop 455 has a driving element. The driving elements are used to control the size of the opening of the aperture stop 455 to control the size of the third stop PA3 and thus the size of the cone angle at which the illumination beam IL is incident on the display 430A. Therefore, after the second F value of the lens module 440 is determined, the size of the first F value of the illumination system 450A can be controlled by the aperture stop 455, so that the head-mounted display device 400A meets the condition that the first F value is greater than or equal to the second F value.

Fig. 21 is a schematic diagram illustrating a head-mounted display device according to an embodiment of the invention. Referring to fig. 21, the head mounted display device 400C of the present embodiment includes an illumination system 450C, a display 430C, a lens module 440, and a waveguide system. The waveguide system includes a first waveguide element 410 and a second waveguide element 420. In the present embodiment, the display 330A includes, for example, a Digital Light Processing (DIGITAL LIGHT PROCESSING)^TMDLP for short^TM) A projection system or a Liquid Crystal On Silicon (LCoS) projection system for converting the illumination beam IL from the illumination system 450C into an image beam ML. The image beam ML is delivered to the projection target P via the waveguide system. In this embodiment, the waveguide system can be operated in a manner sufficiently taught and constructed as described in the description of the embodiment of FIGS. 1-14BDescription of the embodiments is provided.

In this embodiment, illumination system 450C is configured to provide an illumination beam IL to display 430C. Illumination system 450C includes illumination source 451, light equalizing element 457, collimating lens group 453C, aperture stop 455, and prism module 459C. The illumination source 451 provides an illumination beam IL. The illumination beam IL is transmitted to the display 430C via the light equalizing element 357, the aperture stop 355, the collimating lens group 453C, and the prism module 459C. In the present embodiment, the collimating lens group 453C includes lenses 453_1, 453_ 2. The aperture stop 455 is disposed between lenses 453_1, 453_2 in the collimating lens group 353C. The light equalizing element 457 is, for example, a light integrating rod. In the present embodiment, the illumination beam IL from the illumination source 451 converges within the illumination system 450C to the third diaphragm PA 3. A third diaphragm PA3 is located at the aperture diaphragm 455. In this embodiment, the aperture stop 455 has a driving element. The driving element is used to control the size of the opening of the aperture diaphragm 455 to control the size of the third diaphragm PA 3. Thus, the aperture stop 455 can adjust the amount of illumination beam IL passing through its opening. In the present embodiment, the prism module 459C includes a first prism 352_1 and a second prism 352_ 2. The illumination beam IL from the collimating lens group 453C is reflected to the display 430C via the first prism 352_1, converted into an image beam ML and transmitted to the lens module 440 through the second prism 352_ 2.

In the present embodiment, the aperture diaphragm 455 can be adjusted to control the size of the third diaphragm PA3 by adjusting the size of the opening, and the size of the third diaphragm PA3 can affect the size of the cone angle θ 1 of the illumination beam IL incident on the display 430C. Therefore, after the second F value of the lens module 440 is determined, the size of the first F value of the illumination system 450C can be controlled by the aperture stop 455, so that the head-mounted display device 400C meets the condition that the first F value is greater than or equal to the second F value.

In summary, in the exemplary embodiments of the invention, the first diaphragm is located in the first waveguide device, and the second diaphragm is located at the projection target, so that the head-mounted display device provides a large viewing angle and the waveguide system has a small volume. In the exemplary embodiment of the present invention, the diffusion coating of each light splitting element can be determined according to different reflectivity requirements or product designs, so that the image frame in the projection target can be kept uniform and has good display quality. In an exemplary embodiment of the invention, the third light field is within the illumination system and the aperture stop is arranged at the third stop. The head-mounted display device can pass through the aperture diaphragm to control the third diaphragm and the first F value of the illumination system, so that the head-mounted display device meets the condition that the first F value is greater than or equal to the second F value of the lens module, thereby improving ghost in an image and providing good display quality.

The above description is only an example of the present invention, and the scope of the present invention should not be limited thereby, and all the simple equivalent changes and modifications made according to the claims and the contents of the specification should be covered by the present invention. It is not necessary for any embodiment or claim of the invention to address all of the objects, advantages, or features disclosed herein. In addition, the abstract and the title of the specification are provided for assisting the search of patent documents and are not intended to limit the scope of the invention. Furthermore, the terms "first", "second", and the like in the description or the claims are used only for naming elements (elements) or distinguishing different embodiments or ranges, and are not used for limiting the upper limit or the lower limit on the number of elements.

List of reference numerals

100. 200, 300A, 300B, 300C, 400A, 400B, 400C, 500, 600, 700, 800, 900: head-mounted display device

110. 210, 310, 410, 510, 610, 710, 810, 910: first waveguide element

120. 220, 320, 420, 520, 620, 720, 820, 920: second waveguide element

130. 230, 330A, 330B, 330C, 430A, 430B, 430C, 830: display device

140. 240, 340, 440, 840: lens module

350A, 350B, 350C, 450A, 450B, 450C: lighting system

351. 451: illumination light source

352. 352_1, 352_2, 359_1, 359_2, 359_ 3: prism

353. 453C: collimating lens group

355. 455: aperture diaphragm

357. 457: light equalizing element

358: driving element

359A, 359B, 359C, 459A, 459B, 459C: prism module

453_1, 453_ 2: lens and lens assembly

521. 621, 721: reflection structure

530. 630, 730, 850, 930: third waveguide element

532: fixing piece

960. 970: polarizing element

A1: optical axis

A2: visual axis

A3: reference axis

D1, D2: distance between two adjacent plates

ES 3: the third light emitting surface

IS 3: third light incident surface

IL: illuminating light beam

ML: image light beam

P: projecting an object

PA 1: first diaphragm

PA1 ', PA1 ", PA 1"': light diaphragm

PA 2: second diaphragm

PA 3: third diaphragm

PC: center position

R: reflective layer

S11, S13, S14: first light incident surface

S12, ES 1: the first light emitting surface

S23, S15: reflecting surface

S21, IS 2: second light incident surface

S22, ES 2: the second light emitting surface

SX11, SY 21: first surface

SX12, SY 22: second surface

SRN, SR (N + 1): curve line

X: second direction

X1, X2, X3, X4, X5, X6, 531, 631, 731, 831, 931: second light splitting element

Y: a first direction

Y1, Y2, Y3, Y4, 811, 911: first light splitting element

Z: third direction

θ 1, θ 2: taper angle

Claims (13)

1. A head-mounted display device, comprising:

a display for providing an image beam that is projected to a projection target;

a first waveguide element including a first light incident surface, a first light emitting surface, and a plurality of first light splitting elements, wherein the image light beam from the display enters the first waveguide element through the first light incident surface, the image light beam converges to a first diaphragm within the first waveguide element, and the image light beam exits the first waveguide element through the first light emitting surface, wherein the first diaphragm is located within the first waveguide element, the first light splitting elements are arranged along a first direction, a distance between the first diaphragm and a center position of a first light splitting element of the first light splitting elements in the first direction is D1, a distance between a reference axis and the center position of the first light splitting element in the first direction is D2, wherein the distance D1 is greater than the distance D2, and the projection target has a viewing axis perpendicular to the first direction, the boresight is translated toward the first waveguide element to produce the reference axis at a reference plane within the first waveguide element, and the reference plane passes through a center location of the first sheet of light splitting elements; and

the second waveguide element is connected to the first waveguide element, and the second waveguide element includes a second light incident surface, a second light emitting surface, and a plurality of second light splitting elements, wherein the image beam from the first waveguide element is incident on the second waveguide element through the second light incident surface, and the image beam leaves the second waveguide element through the second light emitting surface and is projected to a second diaphragm outside the second waveguide element, wherein the second diaphragm is located at the projection target.

2. The head-mounted display apparatus according to claim 1, wherein the second light splitting elements are arranged in a second direction, the image light beam is transmitted in the first direction within the first waveguide element, and the image light beam exits the first waveguide element after being reflected by the first light splitting elements.

3. The head-mounted display device of claim 2, further comprising:

a lens module having an optical axis and disposed between the display and the first waveguide element, wherein the lens module is configured to produce a viewing angle corresponding to a viewing angle at which the image beam is received at the projection target.

4. The head-mounted display apparatus according to claim 3, wherein the optical axis of the lens module is perpendicular to the first direction and parallel to the visual axis of the projection target, and the angle of view of the projection target receiving a diagonal direction of an image formed by the image beam is 30 to 50 degrees.

5. The head-mounted display apparatus according to claim 3, wherein the optical axis of the lens module is parallel to the first direction and perpendicular to the visual axis of the projection target, and the angle of view of the projection target receiving a diagonal direction of an image formed by the image beam is 50 to 90 degrees.

6. The head-mounted display apparatus according to claim 3, wherein the projection target receives a diagonal view angle of the image formed by the image beam at 30 to 90 degrees.

7. The head-mounted display device of claim 3, wherein the viewing angles generated by the lens module include a first viewing angle and a second viewing angle, the size of the first viewing angle being determined according to the first waveguide element, and the size of the second viewing angle being determined according to the second waveguide element.

8. The head-mounted display device of claim 3, wherein the first light incident surface is disposed opposite to the first light emitting surface, and the optical axis of the lens module is perpendicular to the first direction.

9. The head-mounted display device of claim 3, wherein the first light incident surface is adjacent to the first light emitting surface, and the optical axis of the lens module is parallel to the first direction.

10. The head-mounted display device of claim 3, wherein the first light incident surface is adjacent to the first light emitting surface, and the optical axis of the lens module is perpendicular to the first direction and parallel to the second direction.

11. The head-mounted display device of claim 1, wherein the second light incident surface and the second light emitting surface are on the same surface.

12. The head-mounted display device of claim 1, wherein the first waveguide element and the second waveguide element have a spacing therebetween.

13. The head-mounted display device of claim 1, wherein a number of the plurality of second pieces of light splitting elements of the second waveguide element is greater than a number of the plurality of first pieces of light splitting elements of the first waveguide element.

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