Virtual reality system and method for controlling operation modes of virtual reality system

CROSS REFERENCE TO RELATED APPLICATIONS

0001This application claims the benefit of U.S. Provisional Application No. 62/087,593, filed Dec. 4, 2014, and U.S. Provisional Application No. 62/170,878, filed Jun. 4, 2015, the entirety of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

00021. Field of the Invention

0003The invention relates to a virtual reality system, and more particularly to a head mounted display apparatus for a virtual reality system.

00042. Description of the Related Art

0005Displays with virtual image generation are often used in display devices which are located close to the eyes, so-called near-to-eye displays. Such display devices are known, for example, as head mounted displays (HMD).

0006An HMD is a display device that a person wears on the head in order to have video information directly displayed in front of the eyes. HMDs are also known as near-to-eye displays. An HMD has either one or two small CRT, LCD or OLED displays with magnifying lenses and other optical elements. The displays and optics are typically embedded in a helmet, glasses, or a visor, which a user can wear. Lenses and other optical components are used to give the user the perception that the images are coming from a greater distance, to prevent eyestrain. In HMDs that use a single display, the image is typically projected through optics that split the image into two identical images, and redirects each image to the respective eye. With two displays, the HMD can show stereoscopic images. The stereoscopic images attempt to create depth in the images by simulating the angular difference between the images viewed by each eye when looking at an object, due to the different positions of the eyes. This angular difference is one of the key parameters the human brain uses in processing images to create depth perception or distance in human vision.

BRIEF SUMMARY OF THE INVENTION

0007A virtual reality system and a method for controlling the operation modes of a virtual reality system are provided. An embodiment of a virtual reality system is provided. The virtual reality system comprises a host device, a transmission cable, and a head mounted display apparatus to be worn by a user and coupled to the host device via the transmission cable. The head mounted display apparatus comprises a multimedia module, a multi-sensing module, a peripheral hub, a power management device, and a micro control unit. The multimedia module receives multimedia content from the host device via a first signal path of the transmission cable. The multi-sensing module obtains sensing information regarding the head mounted display apparatus and the user. The peripheral hub receives communication data from the host device via a second signal path of the transmission cable, and provides the sensing information to the host device via the second signal path of the transmission cable. The power management device controls power status of the multimedia module, the multi-sensing module, and the peripheral hub according to a power voltage from the host device via a third signal path of the transmission cable. The micro control unit detects which mode the virtual reality system is operating in according to the signal status of the first and second signal paths of the transmission cable, so as to notify the power management device to control the power status of the multimedia module, the multi-sensing module, and the peripheral hub.

0008Furthermore, a method for controlling operation modes of a virtual reality system is provided. The virtual reality system comprises a host device, a head mounted display apparatus to be worn by the user, and a transmission cable coupled between the host device and the head mounted display apparatus. The head mounted display apparatus detects whether a first signal exists in a first signal path of the transmission cable when a power voltage from the host device is received. The head mounted display apparatus detects whether a second signal exists in a second signal path of the transmission cable when the first signal is received. The head mounted display apparatus controls the head mounted display apparatus to operate in a full operation mode when the first signal exists in the first signal path of the transmission cable and the second signal exists in the second signal path of the transmission cable. The head mounted display apparatus controls the head mounted display apparatus to operate in a mobile mode when the first signal exists in the first signal path of the transmission cable and the second signal does not exist in the second signal path of the transmission cable.

0009A detailed description is given in the following embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

0010The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

0011<figref idref="DRAWINGS">FIG. 1</figref> shows a virtual reality system according to an embodiment of the invention;

0012<figref idref="DRAWINGS">FIG. 2</figref> shows an example of the head mounted display apparatus of <figref idref="DRAWINGS">FIG. 1</figref> according to an embodiment of the invention;

0013<figref idref="DRAWINGS">FIG. 3</figref> shows an example of the multi-sensing module of <figref idref="DRAWINGS">FIG. 2</figref> according to an embodiment of the invention;

0014<figref idref="DRAWINGS">FIG. 4</figref> shows an example of the multimedia module of <figref idref="DRAWINGS">FIG. 2</figref> according to an embodiment of the invention;

0015<figref idref="DRAWINGS">FIG. 5</figref> shows an example of the host device of <figref idref="DRAWINGS">FIG. 1</figref> according to an embodiment of the invention;

0016<figref idref="DRAWINGS">FIG. 6A</figref> shows an exemplary architecture of the virtual reality system of <figref idref="DRAWINGS">FIG. 1</figref> according to an embodiment of the invention;

0017<figref idref="DRAWINGS">FIG. 6B</figref> shows a schematic illustrating connection architecture inside the virtual reality system according to the architecture of <figref idref="DRAWINGS">FIG. 6A</figref>;

0018<figref idref="DRAWINGS">FIG. 6C</figref> shows an exemplary architecture of the virtual reality system of <figref idref="DRAWINGS">FIG. 1</figref> according to another embodiment of the invention;

0019<figref idref="DRAWINGS">FIG. 6D</figref> shows an exemplary architecture of the virtual reality system of <figref idref="DRAWINGS">FIG. 1</figref> according to another embodiment of the invention;

0020<figref idref="DRAWINGS">FIG. 7</figref> shows a virtual reality system according to another embodiment of the invention;

0021<figref idref="DRAWINGS">FIG. 8</figref> shows an exemplary architecture of a virtual reality system according to another embodiment of the invention;

0022<figref idref="DRAWINGS">FIG. 9</figref> shows an exemplary architecture of a virtual reality system according to another embodiment of the invention;

0023<figref idref="DRAWINGS">FIG. 10</figref> shows a table illustrating the multiple power operation modes provided by a virtual reality system according to an embodiment of the invention;

0024<figref idref="DRAWINGS">FIGS. 11A and 11B</figref> show a method for controlling operation modes of a head mounted display apparatus according to an embodiment of the invention;

0025<figref idref="DRAWINGS">FIG. 12</figref> shows a flow chart illustrating how the head mounted display apparatus <b>104</b> enter the MFG mode according to an embodiment of the invention;

0026<figref idref="DRAWINGS">FIG. 13</figref> shows a method for controlling operation modes of a head mounted display apparatus according to another embodiment of the invention;

0027<figref idref="DRAWINGS">FIG. 14</figref> shows an exemplary architecture of a virtual reality system according to another embodiment of the invention;

0028<figref idref="DRAWINGS">FIG. 15</figref> shows a controller according to an embodiment of the invention;

0029<figref idref="DRAWINGS">FIG. 16</figref> shows a method for controlling operation modes of a controller according to an embodiment of the invention;

0030<figref idref="DRAWINGS">FIG. 17</figref> shows a base station according to an embodiment of the invention; and

0031<figref idref="DRAWINGS">FIG. 18</figref> shows a method for controlling operation modes of a base station according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

0032The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.

0033<figref idref="DRAWINGS">FIG. 1</figref> shows a virtual reality system <b>10</b> according to an embodiment of the invention. The virtual reality system <b>10</b> comprises a host device <b>102</b>, a head mounted display apparatus <b>104</b> to be worn by a user, and a transmission cable <b>106</b> (optional) connected between an interface unit <b>101</b> of the host device <b>102</b> and an interface unit <b>103</b> of the head mounted display apparatus <b>104</b>. The interface unit <b>101</b> of the host device <b>102</b> comprises a first host interface <b>20</b>A for providing a multimedia content CXT to the head mounted display apparatus <b>104</b>, a second host interface <b>20</b>B for providing communication data DAT to the head mounted display apparatus <b>104</b>, and a third host interface <b>20</b>C for providing a power voltage PWR to power the head mounted display apparatus <b>104</b>. Furthermore, the interface unit <b>103</b> of the head mounted display apparatus <b>104</b> has a first slave interface <b>30</b>A capable of being coupled to the first host interface <b>20</b>A via the transmission cable <b>106</b>, a second slave interface <b>30</b>B capable of being coupled to the second host interface <b>20</b>B via the transmission cable <b>106</b>, and a third slave interface <b>30</b>C capable of being coupled to the third host interface <b>20</b>C via the transmission cable <b>106</b>. The head mounted display apparatus <b>104</b> is capable of playing the multimedia content CXT from the host device <b>102</b>, and sensing information INFO_Sregarding the head mounted display apparatus <b>104</b> and/or the user. Based on the information sensed by the head mounted display apparatus <b>104</b>, the host device <b>102</b> can timely modulate the multimedia content CXT. In one embodiment, the host device <b>102</b> is capable of processing a multimedia source and generating the multimedia content CXT according to the multimedia source and the information sensed by the head mounted display apparatus <b>104</b>.

0034<figref idref="DRAWINGS">FIG. 2</figref> shows an example of the head mounted display apparatus <b>104</b> of <figref idref="DRAWINGS">FIG. 1</figref> according to an embodiment of the invention. In the embodiment, the head mounted display apparatus <b>104</b> further comprises a multi-sensing module <b>202</b>, a multimedia module <b>204</b>, a micro control unit <b>206</b>, a peripheral hub <b>208</b>, a power management device <b>210</b>, and a wireless module <b>212</b>. The multi-sensing module <b>202</b> can sense the position of the user, the biometrical status of the user, and/or the environment surrounding the head mounted display apparatus <b>104</b> to generate the sensing information INFO_Swhen the user is wearing the head mounted display apparatus <b>104</b>. In an exemplary embodiment, the sensing information INFO_Smay comprise position information INFO_P, user information INFO_U, and/or environment information INFO_E. The position information INFO_Pcan comprise movement information, orientation information, tilt angle information, and/or location information regarding the head mounted display apparatus <b>104</b>. The user information INFO_Ucan comprise biometrical information about the user and/or eye view information sensed by the multi-sensing module <b>202</b>. Furthermore, the environment information INFO_Ecan comprise images/video and/or depth information captured by the multi-sensing module <b>202</b>.

0035In <figref idref="DRAWINGS">FIG. 2</figref>, the multimedia module <b>204</b> can receive the multimedia content CXT from the first host interface <b>20</b>A of the host device <b>102</b> of <figref idref="DRAWINGS">FIG. 1</figref> through the first slave interface <b>30</b>A of the head mounted display apparatus <b>104</b>. The multimedia module <b>204</b> can process and play the multimedia content CXT, e.g. audio, image, or video content. The multimedia module <b>204</b> can be coupled to the multi-sensing module <b>202</b>, so as to obtain the sensing information INFO_S, and thus display parameters, such as brightness and refresh time, can be modulated by the multimedia module <b>204</b> according to the sensing information INFO_S. Furthermore, the micro control unit (MCU) <b>206</b> is electrically coupled to the multi-sensing module <b>202</b> and the multimedia module <b>204</b>. The micro control unit <b>206</b> can issue control information to coordinate functions of the multi-sensing module <b>202</b> and the multimedia module <b>204</b> according to the communication data DAT from the host device <b>102</b>. The micro control unit <b>206</b> can receive the sensing information INFO_Sfrom the multi-sensing module <b>202</b>, and transmit the sensing information INFO_Sto the host device <b>102</b> via the peripheral hub <b>208</b> and the second slave interface <b>30</b>B. The wireless module <b>212</b> can communicate with other remote device, such as a controller, and provides information from the other remote device to the micro control unit <b>206</b>. Thus, the micro control unit <b>206</b> can issue the information to the host device <b>102</b> via the peripheral hub <b>208</b> and the second slave interface <b>30</b>B.

0036Referring to <figref idref="DRAWINGS">FIG. 1</figref> and <figref idref="DRAWINGS">FIG. 2</figref> together, the peripheral hub <b>208</b> can receive the communication data DAT from the second host interface <b>20</b>B of the host device <b>102</b> through the second slave interface <b>30</b>B of the head mounted display apparatus <b>104</b>. The peripheral hub <b>208</b> is coupled to the multi-sensing module <b>202</b>, so as to receive the sensing information INFO_S. Furthermore, the peripheral hub <b>208</b> is also coupled to the micro control unit <b>206</b>, so as to receive the control information. The peripheral hub <b>208</b> may be coupled to a plurality of peripheral devices of the head mounted display apparatus <b>104</b>, such as microphones, speakers, or an extended hub. The peripheral hub <b>208</b> can provide the sensing information INFO_Sto the second host interface <b>20</b>B of the host device <b>102</b> through the second slave interface <b>30</b>B of the head mounted display apparatus <b>104</b>. Furthermore, the power management device <b>210</b> can be connected to the third host interface <b>20</b>C of the host device <b>102</b> through the third slave interface <b>30</b>C of the head mounted display apparatus <b>104</b>, so as to receive the power voltage PWR from the host device <b>102</b>. In the embodiment, the power management device <b>210</b> is connected to each component of the head mounted display apparatus <b>104</b> for powering the components, including the multi-sensing module <b>202</b>, the multimedia module <b>204</b>, the micro control unit <b>206</b>, the peripheral hub <b>208</b>, and the wireless module <b>212</b>. The power management device <b>210</b> comprises a plurality of power circuits, wherein each power circuit is capable of modulating a supply power according to the power voltage PWR from the host device <b>102</b>, and providing the supply power to power the corresponding component according to the control information from the micro control unit <b>206</b>. Specifically, the power management device <b>210</b> can perform power management control and peripheral control according to the control information from the micro control unit <b>206</b>.

0037<figref idref="DRAWINGS">FIG. 3</figref> shows an example of the multi-sensing module <b>202</b> of <figref idref="DRAWINGS">FIG. 2</figref> according to an embodiment of the invention. The multi-sensing module <b>202</b> comprises a position sensing device <b>302</b> for obtaining the position information INFO_Pcorresponding to the head mounted display apparatus <b>104</b>, a user sensing device <b>304</b> for obtaining the user information INFO_U, and/or an environment sensing device <b>306</b> for obtaining the environment information INFO_E, wherein the multi-sensing module <b>202</b> provides the sensing information INFO_Saccording to the position information INFO_P, the user information INFO_U, and the environment information INFO_E. The position sensing device <b>302</b> comprises a plurality of sensors <b>308</b> for sensing the position information INFO_Pof the head mounted display apparatus <b>104</b>. A position reference device can be located at a distance from the head mounted display apparatus <b>104</b>, so as to wirelessly provide reference information to the position sensing device <b>302</b>. Thus, the position sensing device <b>302</b> can use the reference information to generate the position information INFO_P. Furthermore, the user sensing device <b>304</b> comprises at least one measurement device <b>310</b> for sensing the user information INFO_U, such as an Inter-pupillary distance (IPD) measurement device for measuring eye view information of the user, e.g. a visual angle of the user. The environment sensing device <b>306</b> comprises at least two cameras <b>312</b> for capturing images/video of objects which the head mounted display apparatus <b>104</b> is facing, and obtaining the depth information of the objects in relative to the head mounted display apparatus <b>104</b>. A depth map can be calculated by the head mounted display apparatus <b>104</b> or the host device <b>102</b> according to the depth information. Furthermore, the camera lens of the cameras <b>312</b> can be moved by the micro control unit <b>206</b>, so as to obtain more depth information for the depth map. The cameras <b>312</b> are spatially separated apart from each other. The cameras <b>312</b> can capture images and generate parallax information of the captured images, wherein the field of view (FOV) of the cameras at least partially overlap so that the parallax information can be generated. The parallax information can be provided to the host device <b>102</b> as depth information, which can be calculated by the host device <b>102</b>, so as to generate a depth map or a depth model of the space or object faced by the head mounted display apparatus <b>104</b>. In one embodiment, the cameras <b>312</b> are allocated in parallel and with a tilt angle between the viewing direction at which the head mounted display apparatus <b>104</b> can be viewed by the user. With the tilt angle, the cameras <b>312</b> can sense the lower region which the head mounted display apparatus <b>104</b> is facing. Moreover, the host device <b>102</b> is capable of monitoring a clear zone in which the head mounted display apparatus <b>104</b> is facing according to the depth information. Thus, the virtual reality system <b>10</b> is capable of alerting the user when the clear zone falls into a short distance range. For example, the head mounted display apparatus <b>104</b> and the host device <b>102</b> can alert the user to obstructions in a room.

0038<figref idref="DRAWINGS">FIG. 4</figref> shows an example of the multimedia module <b>204</b> of <figref idref="DRAWINGS">FIG. 2</figref> according to an embodiment of the invention. The multimedia module <b>204</b> can process and play the multimedia content CXT, e.g. audio, image, or video content. The multimedia module <b>204</b> comprises at least one display section <b>408</b> and a multimedia bridge <b>410</b>. Each display section <b>408</b> can comprise a lens <b>412</b>, and a display module <b>414</b>. The audio unit <b>416</b> is capable of delivering audio sounds of the multimedia content CXT (i.e. the audio part of the multimedia content CXT) or recording sounds from the user or environment. The audio unit <b>416</b> is coupled to the multimedia bridge <b>410</b> for an audio playback function. Furthermore, referring to <figref idref="DRAWINGS">FIG. 4</figref> and the <figref idref="DRAWINGS">FIG. 2</figref> together, the audio unit <b>416</b> is coupled to the peripheral hub <b>208</b> for a microphone function when a microphone is coupled to the peripheral hub <b>208</b>. The audio unit <b>416</b> may comprise an audio codec for coding/decoding audio signals of the multimedia content CXT, and for coding/decoding the signals of the microphone and/or a speaker/earphone coupled to the peripheral hub <b>208</b>. The multimedia bridge <b>410</b> is coupled between the first slave interface <b>30</b>A of the head mounted display apparatus <b>104</b> and the display section <b>408</b> for transforming the multimedia content CXT (e.g. the video part of the multimedia content) into display signals that are readable by the display section <b>408</b>.

0039Referring back to <figref idref="DRAWINGS">FIG. 1</figref> and <figref idref="DRAWINGS">FIG. 2</figref> together, the virtual reality system <b>10</b> can operate in various power-saving modes. If the head mounted display apparatus <b>104</b> operates in a predetermined condition, the host device <b>102</b> can send the communication data DAT to the micro control unit <b>206</b>, so as to perform a power-saving operation on the head mounted display apparatus <b>104</b>. The micro control unit <b>206</b> is capable of performing a first power-saving operation on the multi-sensing module <b>202</b> when the multi-sensing module <b>202</b> has been operated in a predetermined condition. For example, if the host device <b>102</b> generates or modulates the multimedia content CXT without using the sensing information INFO_S, the host device <b>102</b> can control the micro control unit <b>206</b> to turn off the multi-sensing module <b>202</b> via the transmission cable <b>106</b>. The head mounted display apparatus <b>104</b> may comprise a sensor (not shown) for monitoring whether the head mounted display apparatus <b>104</b> is worn by a user. Furthermore, the sensor is also capable of transmitting a trigger signal to the micro control unit <b>206</b> according to the result of said monitoring operation showing that the head mounted display apparatus <b>104</b> is not worn by the user. In response to the trigger signal, the micro control unit <b>206</b> can perform a second power-saving operation on the multimedia module <b>204</b> and/or the multi-sensing module <b>202</b>. The sensor can be a capacitive sensor embedded inside the head mounted display apparatus <b>104</b> and facing inward for detecting whether the head mounted display apparatus <b>104</b> is worn by the user. Moreover, the transmission cable <b>106</b> is coupled between the host device <b>102</b> and head mounted display apparatus <b>104</b>, and is capable of transmitting the multimedia content CXT, the communication data DAT, and the power voltage PWR from the host device <b>102</b> to the head mounted display apparatus <b>104</b>. Furthermore, the transmission cable <b>106</b> can transmit the sensing information INFO_Sfrom the head mounted display apparatus <b>104</b> to the host device <b>102</b>. In another embodiment, the multimedia content CXT, the communication data DAT, or the sensing information INFO_Scan be transmitted wirelessly between the host device <b>102</b> and the head mounted display apparatus <b>104</b> by using wireless communication technologies, e.g. WiGig technology.

0040<figref idref="DRAWINGS">FIG. 5</figref> shows an example of the host device <b>102</b> of <figref idref="DRAWINGS">FIG. 1</figref> according to an embodiment of the invention. The host device <b>102</b> comprises a computing device <b>502</b> for generating the multimedia content CXT. The computing device <b>502</b> may be a personal computer, NB, or a smart phone or any other portable device with a powerful processor inside. The computing device <b>502</b> can receive a multimedia source from a storage unit or Internet network, and the computing device <b>502</b> is capable of generating the multimedia content CXT according to the multimedia source and the sensing information INFO_Sfrom the head mounted display apparatus <b>104</b>. The computing device <b>502</b> is also capable of generating the communication data according to the sensing information INFO_S. The host device <b>102</b> may further comprise a connection control unit <b>504</b> coupled between the computing device <b>502</b> and the transmission cable <b>106</b> of <figref idref="DRAWINGS">FIG. 1</figref>, wherein the connection control unit <b>504</b> is capable of enhancing the signal strength of the communication data DAT and/or the sensing information INFO_Scommunicated between the computing device <b>502</b> and the connection control unit <b>504</b>. Furthermore, the connection control unit <b>504</b> can connect to a power source, so that the connection control unit <b>504</b> is capable of transmitting the power voltage PWR to a power path of the transmission cable <b>106</b>. In one embodiment, the connection control unit <b>504</b> comprises a switch, which is used to control the supply of the multimedia content CXT, the communication data DAT, and/or the power voltage PWR to the transmission cable <b>106</b>.

0041<figref idref="DRAWINGS">FIG. 6A</figref> shows an exemplary architecture of the virtual reality system <b>10</b> of <figref idref="DRAWINGS">FIG. 1</figref> according to an embodiment of the invention. In <figref idref="DRAWINGS">FIG. 6A</figref>, the connection control unit <b>504</b> is connected to the computing device <b>502</b> through a pre-stage cable <b>606</b>. The pre-stage cable <b>606</b> can transmit the multimedia content CXT, the communication data DAT, and the sensing information INFO_Sbetween the computing device <b>502</b> and the connection control unit <b>504</b>, and it can transmit the power voltage PWR from the power source to the connection control unit <b>504</b>. The connection control unit <b>504</b> is connected to the head mounted display apparatus <b>104</b> via the transmission cable <b>106</b>. The transmission cable <b>106</b> can transmit the multimedia content CXT, the communication data DAT, the sensing information INFO_S, and/or the power voltage PWR between the connection control unit <b>504</b> and the head mounted display apparatus <b>104</b>. In the embodiment, label <b>107</b> represents the virtual objects that are viewed by the user wearing the head mounted display apparatus <b>104</b>.

0042<figref idref="DRAWINGS">FIG. 6B</figref> shows a schematic illustrating a connection architecture inside the virtual reality system <b>10</b> according to the architecture of <figref idref="DRAWINGS">FIG. 6A</figref>. In the embodiment, the computing device <b>502</b> can comprise a processor <b>602</b> and a storage unit <b>604</b>, wherein the computing device <b>502</b> is capable of providing the multimedia source. The processor <b>602</b> can generate the multimedia content CXT according to the multimedia source and the sensing information INFO_Sfrom the head mounted display apparatus <b>104</b> via the pre-stage cable <b>606</b>. The processor <b>602</b> can also generate the communication data DAT according to the sensing information INFO_S. The pre-stage cable <b>606</b> comprises a pre-stage multimedia path <b>606</b>-<b>1</b> for transmitting the multimedia content CXT, a pre-stage communication path <b>606</b>-<b>2</b> for transmitting the communication data DAT and/or the sensing information INFO_S, and a pre-stage power path <b>606</b>-<b>3</b> for providing the power voltage PWR to the connection control unit <b>504</b>. In the embodiment, the connection control unit <b>504</b> is connected to a power adapter <b>608</b> via the pre-stage power path <b>606</b>-<b>3</b>. It should be noted that the power adapter <b>608</b> can be integrated in or independent from the computing device <b>502</b>. The power adapter <b>608</b> can provide the power voltage PWR to the connection control unit <b>504</b> through the pre-stage power path <b>606</b>-<b>3</b>. The transmission cable <b>106</b> can comprise a multimedia path <b>106</b>-<b>1</b> for transmitting the multimedia content CXT, a communication path <b>106</b>-<b>2</b> for transmitting the communication data DAT and/or the sensing information INFO_S, and a power path <b>106</b>-<b>3</b> for transmitting the power voltage PWR.

0043<figref idref="DRAWINGS">FIG. 6C</figref> shows an exemplary architecture of the virtual reality system <b>10</b> of <figref idref="DRAWINGS">FIG. 1</figref> according to another embodiment of the invention. The computing device <b>502</b> is capable of wirelessly transmitting the multimedia content CXT to the connection control unit <b>504</b> and wirelessly receiving the sensing information INFO_Sfrom the connection control unit <b>504</b>. The connection control unit <b>504</b> may comprise a transceiver <b>505</b> for wirelessly communicating with the computing device <b>502</b>. Furthermore, at least one of the connection control unit <b>504</b> and the head mounted display apparatus <b>104</b> comprises a receiving device with at least two antennas each facing a different direction for wirelessly receiving information, e.g. the multimedia content CXT, from the computing device <b>502</b>. The receiving device can be circular and can be mounted on a belt or other wearable apparatus. For example, the head mounted display apparatus <b>104</b> may comprise a helmet, wherein the circular receiving device is encircled around the helmet. The head mounted display apparatus <b>104</b> can comprise a receiver for receiving wireless signals from the computing device <b>502</b> via the circular receiving device. Since the head mounted display apparatus <b>104</b> is to be worn on the head of a user during operation, the user's body, hands or furniture in front of the user will not obstruct the transmission of the wireless signals from the computing device <b>502</b>.

0044<figref idref="DRAWINGS">FIG. 6D</figref> shows an exemplary architecture of the virtual reality system <b>10</b> of <figref idref="DRAWINGS">FIG. 1</figref> according to another embodiment of the invention. The computing device <b>502</b> is capable of wirelessly transmitting the multimedia content CXT to the connection control unit <b>504</b> and wirelessly receiving the sensing information INFO_Sfrom the connection control unit <b>504</b>. The connection control unit <b>504</b> may be allocated inside the head mounted display apparatus <b>104</b>, e.g. the connection control unit <b>504</b> is integrated into the head mounted display apparatus <b>104</b>. The head mounted display apparatus <b>104</b> may comprise a transceiver <b>507</b> for wirelessly communicating with the computing device <b>502</b>. The head mounted display apparatus <b>104</b> may comprise a power source such as a battery (not shown). As described above, the head mounted display apparatus <b>104</b> may also comprise the circular receiving device for receiving wireless signals, which comprises video and/or audio data, transmitted from the computing device <b>502</b>.

0045<figref idref="DRAWINGS">FIG. 7</figref> shows a virtual reality system according to another embodiment of the invention. In <figref idref="DRAWINGS">FIG. 7</figref>, a mobile phone <b>108</b> can receive and transmit Bluetooth signals in response to an event such as a phone call. The connection control unit <b>504</b> can comprise a Bluetooth transceiver <b>702</b> for communicating with the mobile phone <b>108</b>. The computing device <b>502</b> can process the Bluetooth signals received from the connection control unit <b>504</b> and generate alarm indicators to inform the user about the event via the display module <b>414</b> and/or the audio unit <b>416</b>. The computing device <b>502</b> may perform a remote-answer application so that the user can answer a phone call through the audio unit <b>416</b>. In some embodiments, the computing device <b>502</b> can mute or lower the sound of the multimedia content CXT and play the sound of the remote-answer application. The audio unit <b>416</b> of the head mounted display apparatus <b>104</b> can record the user's sound, and then transmit the sound information through the Bluetooth transceiver <b>702</b> of the connection control unit <b>504</b> directly to the mobile phone <b>108</b> without passing through the computing device <b>502</b>.

0046<figref idref="DRAWINGS">FIG. 8</figref> shows an exemplary architecture of a virtual reality system <b>10</b> according to another embodiment of the invention. In <figref idref="DRAWINGS">FIG. 8</figref>, the connection control unit <b>504</b> may comprise a switch device <b>418</b> for switching the authority of the Bluetooth transceiver <b>702</b>. The switch device <b>418</b> may comprise a host circuit for receiving request and audio signals from the computing device <b>502</b> and the peripheral hub <b>208</b>. The switch device <b>418</b> can provide a Bluetooth communication path for the peripheral hub <b>208</b> upon request so that audio signals of the remote-answer application can be communicated between the mobile phone <b>108</b> and the head mounted display device <b>104</b> directly without passing through the computing device <b>502</b>.

0047<figref idref="DRAWINGS">FIG. 9</figref> shows an exemplary architecture of a virtual reality system according to another embodiment of the invention. In <figref idref="DRAWINGS">FIG. 9</figref>, the connection control unit <b>504</b> may comprise a first signal path <b>910</b> connected between the computing device <b>502</b> and the peripheral hub <b>208</b> and a second signal path <b>920</b> connected between the computing device <b>502</b> and the Bluetooth transceiver <b>702</b> of the connection control unit <b>504</b>. The recorded audio sounds of the user can be transmitted from the peripheral hub <b>208</b> to the computing device <b>502</b> through the first signal path <b>910</b>. The computing device <b>502</b> can process the recorded audio sounds, and then transmit the sound signals through the second signal path <b>920</b> to the mobile device <b>108</b>. The audio signal from the mobile device <b>108</b> can be sent to the computing device <b>502</b> through the second signal path <b>920</b>. Accordingly, the computing device <b>502</b> can send the audio signals to the audio unit <b>416</b> of the head mounted display apparatus <b>104</b> through the first signal path <b>910</b>. For example, the computing device <b>502</b> converts the audio signals into the multimedia content CXT, and provides the multimedia content CXT to the head mounted display apparatus <b>104</b>, wherein the second signal path <b>910</b> comprises the transmission cable <b>106</b>. In another embodiment, the Bluetooth transceiver <b>702</b> can be replaced with a wireless signal transceiver capable of transmitting/receiving audible sound, images and/or video captured by the mobile phone <b>108</b>, and the head mounted display apparatus <b>104</b> can play the audio sound, images, and/or video received by the wireless signal transceiver.

0048<figref idref="DRAWINGS">FIG. 10</figref> shows a table illustrating the multiple power operation modes provided by a virtual reality system according to an embodiment of the invention. Referring to <figref idref="DRAWINGS">FIGS. 1-4 and 10</figref> together, the virtual reality system <b>10</b> can provide a waiting for boot mode, a mobile mode, a full operation mode, a display off mode, and/or a manufacturing (MFG) test mode. The head mounted display apparatus <b>104</b> can detect in which mode the virtual reality system <b>10</b> is operating according to the signal status of the first slave interface <b>30</b>A, the second slave interface <b>30</b>B, and the third slave interface <b>30</b>C of the head mounted display apparatus <b>104</b>, and the pressing situation of a power button (not shown) on the head mounted display apparatus <b>104</b>. In the waiting for boot mode, the power status of the multimedia bridge <b>410</b>, the peripheral hub <b>208</b>, the audio unit <b>416</b>, the position sensing device <b>302</b>, and the user sensing device <b>304</b> are inactive (i.e. “OFF”), i.e. the multimedia bridge <b>410</b>, the peripheral hub <b>208</b>, the audio unit <b>416</b>, the position sensing device <b>302</b>, and the user sensing device <b>304</b> are disabled by the micro control unit <b>206</b>. Furthermore, in the mobile mode, the virtual reality system <b>10</b> may be used to play a movie, and there may be no requirement to sense the position or the environment. In the mobile mode, the power status of the multimedia bridge <b>410</b> and the audio unit <b>416</b> are active (i.e. “ON”), and the power status of the peripheral hub <b>208</b>, the position sensing device <b>302</b>, and the user sensing device <b>304</b> are inactive (i.e. “OFF”). In the full operation mode, the power status of the multimedia bridge <b>410</b>, the peripheral hub <b>208</b>, the audio unit <b>416</b>, the position sensing device <b>302</b>, and the user sensing device <b>304</b> are active. If it is detected that the user is not wearing the head mounted display apparatus <b>104</b>, the virtual reality system will enter the display off mode. Thus, the multimedia module <b>204</b> is disabled. However, the position sensing device <b>302</b> is active so that the host device <b>102</b> can detect whether the head mounted display apparatus <b>104</b> is moved. Accordingly, in the display off mode, the power status of the multimedia bridge <b>410</b>, the audio unit <b>416</b>, and the user sensing device <b>304</b> are inactive, and the power status of the peripheral hub <b>208</b>, and the position sensing device <b>302</b> are active. In the MFG test mode, the factory may need to test each function of the head mounted display apparatus <b>104</b>. In the MFG test mode, the power status of the multimedia bridge <b>410</b>, the audio unit <b>416</b>, the position sensing device <b>302</b>, and the user sensing device <b>304</b> are inactive or configured by the testing software used by the factory, and the power status of the peripheral hub <b>208</b> is active.

0049<figref idref="DRAWINGS">FIGS. 11A and 11B</figref> show a method for controlling operation modes of a head mounted display apparatus according to an embodiment of the invention. Referring to <figref idref="DRAWINGS">FIG. 1</figref> and <figref idref="DRAWINGS">FIGS. 11A and 11B</figref> together, first, in an initial state (step S<b>1102</b>), the head mounted display apparatus <b>104</b> is turned off. If there are signals or voltages received by one of the first slave interface <b>30</b>A, the second slave interface <b>30</b>B, and the third slave interface <b>30</b>C of the head mounted display apparatus <b>104</b>, the head mounted display apparatus <b>104</b> will enter a “Waiting for boot” mode (step S<b>1104</b>), wherein the power status of the multimedia bridge <b>410</b>, the peripheral hub <b>208</b>, the audio unit <b>416</b>, the position sensing device <b>302</b>, and the user sensing device <b>304</b> are inactive. Next, the head mounted display apparatus <b>104</b> will detect whether the power button of the head mounted display apparatus <b>104</b> is pressed (step S<b>1106</b>). If the power button of the head mounted display apparatus <b>104</b> is pressed over a time period (step S<b>1108</b>), for example 1 sec, the head mounted display apparatus <b>104</b> will detect whether the third slave interface <b>30</b>C has received the power voltage PWR (step S<b>1110</b>). If the power voltage PWR is detected, the head mounted display apparatus <b>104</b> will detect consequently whether the first slave interface <b>30</b>A has received signals, e.g. the multimedia content CXT (step S<b>1112</b>). If no signal is detected in the first slave interface <b>30</b>A, the head mounted display apparatus <b>104</b> will remain in the “Waiting for boot” mode. If it is detected that the first slave interface <b>30</b>A has received the signals, the head mounted display apparatus <b>104</b> will detect whether the second slave interface <b>30</b>B has received signals, e.g. the communication data DAT (step S<b>1114</b>). If it is detected that the second slave interface <b>30</b>B has received the signals, the head mounted display apparatus <b>104</b> will enter the full operation mode (step S<b>1116</b>), wherein the power status of the multimedia bridge <b>410</b>, the peripheral hub <b>208</b>, the audio unit <b>416</b>, the position sensing device <b>302</b>, and the user sensing device <b>304</b> are active. If no signal is detected in the second slave interface <b>30</b>B, the head mounted display apparatus will enter the mobile mode (step S<b>1118</b>), wherein the power status of the multimedia bridge <b>410</b> and the audio unit <b>416</b> are active, and the power status of the peripheral hub <b>208</b>, the position sensing device <b>302</b>, and the user sensing device <b>304</b> are inactive. During the mobile mode, if it is detected that the second slave interface <b>30</b>B has received signals (step S<b>1120</b>), the head mounted display apparatus <b>104</b> will enter the full operation mode (step S<b>1116</b>). During the full operation mode, if it is detected that the user is not wearing the head mounted display apparatus <b>104</b> (step S<b>1122</b>), the virtual reality system will enter the display off mode (S<b>1124</b>) until it is detected that the head mounted display apparatus <b>104</b> is moved (step S<b>1230</b>). If the head mounted display apparatus <b>104</b> is moved, the virtual reality system will return back to the full operation mode (step S<b>1126</b>). As described above, in the display off mode, the power status of the multimedia bridge <b>410</b>, the audio unit <b>416</b>, and the user sensing device <b>304</b> are inactive, and the power status of the peripheral hub <b>208</b>, and the position sensing device <b>302</b> are active. Thus, by controlling the power status of the circuits of the head mounted display apparatus <b>104</b> in the different modes, power consumption of the head mounted display apparatus <b>104</b> can be controlled.

0050<figref idref="DRAWINGS">FIG. 12</figref> shows a flow chart illustrating how the head mounted display apparatus <b>104</b> enters the MFG mode according to an embodiment of the invention. In the embodiment, if the factory need the head mounted display apparatus to enter the MFG test mode, the factory will only need to connect and disconnect the second slave interface <b>30</b>B in a predetermined sequence while not pressing the power button (as shown in the flow chart, denoted as “Present”, “Idle”, “Absent”, “Present”, “Absent”, “Present”, and then “Power button” consecutively), wherein “Present” (step S<b>1206</b>, step S<b>1212</b>, and step S<b>1216</b>) represents that the second slave interface <b>30</b>B has received signals, and “Absent” (step S<b>1210</b>, and step S<b>1214</b>) represents that no signal has received in the second slave interface <b>30</b>B. Furthermore, “Power button is pressed” represents the power button is pressed within a specific time, e.g. <b>4</b> sec (step S<b>1218</b>). In some situations, a reset button can be designed on the head mounted display apparatus <b>104</b>. If the reset button is pressed (step S<b>1222</b>), and then the power button (step S<b>1218</b>) is pressed, the head mounted display apparatus <b>104</b> will directly enter the MFG mode (step S<b>1220</b>).

0051<figref idref="DRAWINGS">FIG. 13</figref> shows a method for controlling operation modes of a head mounted display apparatus according to another embodiment of the invention. Referring to <figref idref="DRAWINGS">FIG. 1</figref> and <figref idref="DRAWINGS">FIG. 13</figref> together, first, in an initial state (step S<b>1302</b>), the head mounted display apparatus <b>104</b> is turned off. If there are signals or voltages received by one of the first slave interface <b>30</b>A, the second slave interface <b>30</b>B, and the third slave interface <b>30</b>C of the head mounted display apparatus <b>104</b>, the head mounted display apparatus <b>104</b> will enter a “Waiting for boot” mode (step S<b>1304</b>), wherein the power status of the multimedia bridge <b>410</b>, the peripheral hub <b>208</b>, the audio unit <b>416</b>, the position sensing device <b>302</b>, and the user sensing device <b>304</b> are inactive. Next, the head mounted display apparatus <b>104</b> will detect whether the third slave interface <b>30</b>C has received the power voltage PWR (step S<b>1306</b>). If no signal is detected in the third slave interface <b>30</b>C, the head mounted display apparatus <b>104</b> will remain in the “Waiting for boot” mode (step S<b>1304</b>). If the power voltage PWR is detected in the third slave interface <b>30</b>C, the head mounted display apparatus <b>104</b> will detect consequently whether both the first slave interface <b>30</b>A and the second slave interface <b>30</b>B have received signals (step S<b>1308</b>), e.g. the multimedia content CXT and the communication data DAT. If it is detected that only the second slave interface <b>30</b>B has received the signals (S<b>1310</b>), the head mounted display apparatus <b>104</b> will enable the environment sensing device <b>306</b> of <figref idref="DRAWINGS">FIG. 3</figref> (step S<b>1312</b>). After the environment sensing device <b>306</b> is enabled, the head mounted display apparatus <b>104</b> will continue to detect whether both the first slave interface <b>30</b>A and the second slave interface <b>30</b>B have received signals (step S<b>1308</b>). If it is detected that both the first slave interface <b>30</b>A and the second slave interface <b>30</b>B have received the signals, the head mounted display apparatus <b>104</b> will enter a full operation mode (step S<b>1314</b>), wherein the power status of the multimedia bridge <b>410</b>, the peripheral hub <b>208</b>, the audio unit <b>416</b>, the position sensing device <b>302</b>, and the user sensing device <b>304</b> are active. Thus, by controlling the power status of the circuits of the head mounted display apparatus <b>104</b> according to the signals exist in the first slave interface <b>30</b>A and/or the second slave interface <b>30</b>B, power consumption of the head mounted display apparatus <b>104</b> can be controlled. Furthermore, in this embodiment, no power button is implemented in the head mounted display apparatus <b>104</b>.

0052<figref idref="DRAWINGS">FIG. 14</figref> shows an exemplary architecture of a virtual reality system <b>20</b> according to another embodiment of the invention. The virtual reality system <b>20</b> comprises a computing device <b>502</b>, a connection control unit <b>504</b>, a head mounted display apparatus <b>104</b>, two controllers <b>1410</b> and <b>1420</b>, and two base stations <b>1460</b> and <b>1470</b>. In <figref idref="DRAWINGS">FIG. 14</figref>, the connection control unit <b>504</b> is connected to the computing device <b>502</b> through a pre-stage cable <b>606</b>. The pre-stage cable <b>606</b> can transmit the multimedia content CXT, the communication data DAT, and the sensing information INFO_Sbetween the computing device <b>502</b> and the connection control unit <b>504</b>, and it can transmit the power voltage PWR from the power source to the connection control unit <b>504</b>. The connection control unit <b>504</b> is connected to the head mounted display apparatus <b>104</b> via the transmission cable <b>106</b>. The transmission cable <b>106</b> can transmit the multimedia content CXT, the communication data DAT, the sensing information INFO_S, and/or the power voltage PWR between the connection control unit <b>504</b> and the head mounted display apparatus <b>104</b>. In the embodiment, the user holds the controller <b>1410</b> with his left hand, and also holds the controller <b>1420</b> with his right land. The head mounted display apparatus <b>104</b> is capable of communicating with the controllers <b>1410</b> and <b>1420</b> via the wireless module <b>212</b> of <figref idref="DRAWINGS">FIG. 2</figref>, so as to perform a specific application, e.g. game. In the embodiment, the base stations <b>1460</b> and <b>1470</b> are the position reference devices. As described above, each position reference device can be located at a distance away from the head mounted display apparatus <b>104</b>, so as to wirelessly provide reference information to a position sensing device (e.g. <b>302</b> of <figref idref="DRAWINGS">FIG. 3</figref>) of the head mounted display apparatus <b>104</b>. Thus, the position sensing device can use the reference information from the base stations <b>1460</b> and <b>1470</b> to generate the position information INFO_P.

0053<figref idref="DRAWINGS">FIG. 15</figref> shows a controller <b>1500</b> according to an embodiment of the invention. The controller <b>1500</b> comprises a wireless module <b>1510</b>, a processing unit <b>1520</b>, a user interface <b>1530</b>, a motion sensor <b>1540</b>, and a power management unit (PMU) <b>1550</b>. In the embodiment, the processing unit <b>1520</b> can communicate with the wireless module <b>1510</b>, the user interface <b>1530</b>, the motion sensor <b>1540</b>, and the PMU <b>1550</b>, so as to control the circuits and obtain data from the circuits. The wireless module <b>1510</b> is capable of communicating with a wireless module (e.g. <b>212</b> of <figref idref="DRAWINGS">FIG. 2</figref>) of the head mounted display apparatus <b>104</b>. The user interface <b>1530</b> comprises a plurality of buttons. When one button is pressed, the processing unit <b>1520</b> can transmit the information corresponding to the pressed button to the head mounted display apparatus <b>104</b> via the wireless module <b>1510</b>. The motion sensor <b>1540</b> is capable of detecting the motion of the controller <b>1500</b>, and providing the motion information to the processing unit <b>1520</b>. Similarly, the processing unit <b>1520</b> can transmit the motion information to the head mounted display apparatus <b>104</b> via the wireless module <b>1510</b>. Furthermore, the PMU <b>1550</b> can provide the corresponding operating voltages to the wireless module <b>1510</b>, the processing unit <b>1520</b>, the user interface <b>1530</b>, and the motion sensor <b>1540</b>. Moreover, when the controller <b>1500</b> is coupled to a charger (not shown), a battery of the PMU <b>1550</b> is charged by the charger.

0054<figref idref="DRAWINGS">FIG. 16</figref> shows a method for controlling operation modes of a controller according to an embodiment of the invention. Referring to <figref idref="DRAWINGS">FIG. 15</figref> and <figref idref="DRAWINGS">FIG. 16</figref> together, first, in a power off mode (step S<b>1610</b>), the controller <b>1500</b> is turned off, wherein the power status of the processing unit <b>1520</b>, the wireless module <b>1510</b>, and the motion sensor <b>1540</b> are inactive. If it is detected that any button of the user interface <b>1530</b> of the controller <b>1500</b> is pressed over a time period (step S<b>1620</b>), the controller <b>1500</b> will enter a normal mode (step S<b>1630</b>), wherein the power status of the processing unit <b>1520</b>, the wireless module <b>1510</b>, and the motion sensor <b>1540</b> are active. When the controller <b>1500</b> enters the normal mode, the processing unit <b>1520</b> will provide information corresponding to the key event, battery event, or charging event to the head mounted display apparatus <b>104</b> via the wireless module <b>1510</b>. In some embodiments, when one button of the user interface <b>1530</b> is pressed, a key event is present. In some embodiments, when battery status of the battery of the PMU <b>1550</b> is changed, such as the battery capacity of the battery of the PMU <b>1550</b> is lower than or higher than a specific value, a battery event is present. Furthermore, when the controller <b>1500</b> is coupled to a charger, the battery of the PMU <b>1550</b> is charged and a charging event is present. When the controller <b>1500</b> is operating in the normal mode, the controller <b>1500</b> will continue to detect whether any event is present (S<b>1640</b>). If a key event indicating that a power button is pressed over a time period is detected, the controller <b>1500</b> will enter the power off mode (step S<b>1650</b>) after notifying the head mounted display apparatus <b>104</b> and receiving a response from the head mounted display apparatus <b>104</b> corresponding to the key event. As described above, the power status of the processing unit <b>1520</b>, the wireless module <b>1510</b>, and the motion sensor <b>1540</b> are inactive in the power off mode. Moreover, if a specific event is detected, the controller <b>1500</b> will enter a power saving mode (or called as a sleep mode) (step S<b>1660</b>). In some embodiments, the controller <b>1500</b> will notify the head mounted display apparatus <b>104</b> that the controller <b>1500</b> will enter the power saving mode. In one embodiment, the specific event is provided by the head mounted display apparatus <b>104</b>, and the specific event indicates that the head mounted display apparatus <b>104</b> is operating in the display off mode, for example, the head mounted display apparatus <b>104</b> is not being worn by the user. In one embodiment, the operating voltages and/or frequency of the circuits of the controller <b>1500</b> are decreased in the power saving mode. In other embodiments, the specific event is present when the controller <b>1500</b> has not been moved over a time period or the controller <b>1500</b> is coupled to a charger. When the controller <b>1500</b> is operated in the power saving mode, the controller <b>1500</b> will continue to detect whether any event is present. If a wakeup event is obtained in the power saving mode (step S<b>1670</b>), the controller <b>1500</b> will enter the normal mode (step S<b>1630</b>) and notify the head mounted display apparatus <b>104</b>. In some embodiment, the wakeup event is a wireless event provided by the head mounted display apparatus <b>104</b>, wherein the wireless event indicates that the head mounted display apparatus <b>104</b> returns back to the normal mode from the display off mode. In some embodiments, the wakeup event is a motion event indicating that the controller <b>1500</b> is moved. In some embodiments, the wakeup event is a key event indicating that one button of the user interface <b>1530</b> has been pressed. In some embodiments, the wakeup event is a charging event indicating that charging of the battery of the PMU <b>1550</b> is completed or the controller <b>1500</b> is disconnected from the charger.

0055<figref idref="DRAWINGS">FIG. 17</figref> shows a base station <b>1700</b> according to an embodiment of the invention. The base station <b>1700</b> comprises a processing unit <b>1710</b>, a wireless module <b>1720</b>, a signal broadcasting module <b>1730</b>, a motion sensor <b>1740</b>, a user interface <b>1750</b>, and a PMU <b>1760</b>. In the embodiment, the processing unit <b>1710</b> can communicate with the wireless module <b>1720</b>, the signal broadcasting module <b>1730</b>, the motion sensor <b>1740</b>, the user interface <b>1750</b>, and the PMU <b>1760</b>, so as to control the circuits and obtain data from the circuits. Furthermore, the PMU <b>1760</b> can provide the corresponding operating voltages to the processing unit <b>1710</b>, the wireless module <b>1720</b>, the signal broadcasting module <b>1730</b>, the motion sensor <b>1740</b>, and the user interface <b>1750</b>. Referring to <figref idref="DRAWINGS">FIG. 17</figref> and <figref idref="DRAWINGS">FIG. 14</figref> together, in a normal mode, the wireless module <b>1720</b> (e.g. a Bluetooth transceiver) is capable of communicating with the connection control unit <b>504</b> of <figref idref="DRAWINGS">FIG. 14</figref> via the Bluetooth transceiver of the connection control unit <b>504</b>, e.g. the Bluetooth transceiver <b>702</b> of <figref idref="DRAWINGS">FIG. 7</figref>. Furthermore, the signal broadcasting module <b>1730</b> (including a laser) is capable of providing reference information to the head mounted display apparatus <b>104</b>. For example, in a room, the base station <b>1700</b> can provide the reference information to the various head mounted display apparatuses in the room, respectively. Furthermore, when one head mounted display apparatus is being worn by the user, the connection control unit <b>504</b> of the worn head mounted display apparatus will periodically provide a trigger signal to keep the base station <b>1700</b> alive in every specific period, e.g. 10 minutes. In response to the trigger signal received by the wireless module <b>1720</b>, the processing unit <b>1710</b> resets/enables a timer <b>1715</b> to count time. If a specific time period (e.g. 30 minutes) is counted by the timer <b>1715</b> and no trigger signal is received by the wireless module <b>1720</b> during the specific time period, the base station <b>1700</b> will enter a power off mode. Furthermore, the base station <b>1700</b> will enter the normal mode from the power off mode when a power button of the user interface <b>1750</b> is pressed over a time period. In some embodiments, the user interface <b>1750</b> further comprises an indicator capable of indicating whether the base station <b>1700</b> is operating in the normal mode. For example, the indicator is a light emitting diode (LED) device, and when the base station <b>1700</b> is operating in the normal mode, the LED device is turned on by the processing unit <b>1710</b>. To the contrary, when the base station <b>1700</b> is operating in the power off mode, the LED device is turned off. Moreover, the motion sensor <b>1740</b> is capable of detecting the motion of the base station <b>1700</b>, and providing the motion information to the processing unit <b>1710</b>.When the motion information indicates that the base station <b>1700</b> is moved, the processing unit <b>1710</b> can transmit an alarm signal to the head mounted display apparatus <b>104</b> via the wireless module <b>1720</b>.

0056<figref idref="DRAWINGS">FIG. 18</figref> shows a method for controlling operation modes of a base station according to an embodiment of the invention. Referring to <figref idref="DRAWINGS">FIG. 17</figref> and <figref idref="DRAWINGS">FIG. 18</figref> together, first, in a power off mode (step S<b>1810</b>), the base station <b>1700</b> is disabled. If it is detected that a power button of the base station <b>1700</b> is pressed over a time period (step S<b>1820</b>), the base station <b>1700</b> will enter a normal mode (step S<b>1830</b>), and then the timer <b>1715</b> is enabled to count time. Before a specific time period is counted by the timer <b>1715</b>, it is detected whether a trigger signal from a connection control unit of a head mounted display apparatus is received by the wireless module <b>1720</b> in the normal mode (step S<b>1840</b>). If no trigger signal is received by the wireless module <b>1720</b> during the specific time period, the base station <b>1700</b> will enter a power off mode (step S<b>1850</b>). To the contrary, if any trigger signal is received during the specific time period, the base station <b>1700</b> will continue to operate in the normal mode (step S<b>1830</b>). Simultaneously, in response to the trigger signal, the timer <b>1715</b> of the base station <b>1700</b> is reset to count the specific time period again.

0057While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.