Provided is a head-mounted display in which it is easy to photograph eyes of a user that wears the head-mounted display. The HMD that is worn by the user includes a display unit disposed in front of the eyes of the user, an optical system disposed between the display unit and eyes of the user, and an imaging unit disposed between the display unit and the optical system, the imaging unit imaging the display unit in which an image of the eyes of the user is reflected.

TECHNICAL FIELD

The present invention relates to a head-mounted display.

BACKGROUND ART

In a head-mounted display or the like that is worn on a head of a user and in which a video or the like is viewed as disclosed in PTL 1 to 4, a technique has been known in which a position of eyes or line-of-sight direction of the user is detected from an image of the eyes of the user photographed by a camera.

CITATION LIST

Patent Literature

SUMMARY

Technical Problem

When photographing eyes of a user that wears a head-mounted display, a camera is installed in a location (for example, an upper portion or lower portion of an optical system) that is a space between the eyes of the user and the optical system disposed between a display unit and the eyes of the user, and that has no obstruction in viewing the display unit by the user.

Herein, in the head-mounted display that is worn on a head, a distance between the optical system and the eyes of the user that wears the head-mounted display becomes small. Also, an actual state is that a size of the optical system is preferably larger in order to broaden a field of view of the user. Then, there occurs a problem that a photographing angle of the camera to the eyes of the user becomes shallow and it is difficult to photograph the eyes of the user with eyelids, eyelashes, or the like becoming an obstacle.

In view of the foregoing, it is an object of the present invention to provide the head-mounted display in which it is easy to photograph the eyes of the user that wears the head-mounted display.

Solution to Problem

In order to solve the above-described problem, a head-mounted display worn by a user according to the present invention, includes a display unit disposed in front of eyes of the user, an optical system disposed between the display unit and the eyes of the user, and an imaging unit disposed between the display unit and the optical system, the imaging unit imaging the display unit in which an image of the eyes of the user is reflected.

In a mode of the present invention, it may be assumed that the head-mounted display further includes a light-irradiation unit that irradiates light onto the eyes of the user, and the imaging unit images an image of the eyes of the user reflected in the display unit by reflecting the light irradiated by the light-irradiation unit by the eyes of the user.

In this mode, it may be assumed that the light-irradiation unit is disposed between the optical system and the eyes of the user and directly irradiates light onto the eyes of the user.

Further, it may be assumed that the light-irradiation unit is disposed between the display unit and the optical system and irradiates, onto the eyes of the user, reflected light in which light irradiated onto the display unit is reflected.

Further, it may be assumed that the light-irradiation unit irradiates infrared light, and the imaging unit is an infrared camera capable of imaging the infrared light.

Further, in a mode of the present invention, it may be assumed that the head-mounted display further includes a line-of-sight detection unit that detects a line-of-sight direction of the user on the basis of an image including the image of the eyes of the user imaged by the imaging unit.

DESCRIPTION OF EMBODIMENT

FIG. 1is a diagram illustrating an example of a hardware configuration of an HMD10according to an embodiment of the present invention.FIG. 2is a schematic diagram illustrating a first example of a configuration of the HMD10according to the present embodiment.

As illustrated inFIG. 1, the HMD10according to the present embodiment includes, for example, a control unit11, a storage unit12, an input/output unit13, a display unit14, a light-irradiation unit15, and an imaging unit16.

The control unit11includes a program control device such as a central processing unit (CPU), and executes various types of information processing in accordance with programs stored in the storage unit12.

The storage unit12includes a memory device such as a random access memory (RAM) or read-only memory (ROM), and stores programs or the like executed by the control unit11. Further, the storage unit12also functions as a work memory of the control unit11.

The input/output unit13is an input/output interface such as a high-definition multimedia interface (HDMI) (registered trademark) port or a universal serial bus (USB) port, for example.

The display unit14is a display such as a liquid crystal display or an organic electroluminescence (EL) display, for example. The display unit14according to the present embodiment displays, for example, a video or the like expressed by video signals received from an entertainment apparatus such as a home game machine, digital versatile disc (DVD) player, or Blue-ray (registered trademark) player connected via the input/output unit13. In addition, the display unit14according to the present embodiment may be capable of displaying a three-dimensional video.

The light-irradiation unit15is an optical device such as a light-emitting diode (LED). The light-irradiation unit15according to the present embodiment is assumed to irradiate light of a wavelength band other than a visible light band, called infrared light; however, the light-irradiation unit15is not limited to this example, and may be assumed to irradiate light of the visible light band.

The imaging unit16is a camera such as a digital camera for generating an image in which an object is imaged, for example. The imaging unit16according to the present embodiment is assumed to be an infrared camera capable of imaging infrared light; however, the imaging unit16is not limited to this example, and may be a camera capable of imaging visible light. Further, as illustrated inFIG. 2, the imaging unit16according to the present embodiment is disposed so as to image the display unit14and images the display unit14in which an image40of eyes of a user obtained by using infrared light reflected by eyes30of the user is reflected. In addition, the imaging unit16may be assumed to image the display unit14in which the image40of the eyes of the user obtained by using visible light reflected by the eyes30of the user is reflected.

The control unit11further detects a position of the eyes of the user or a line-of-sight direction of the user from an image including the image40of the eyes of the user imaged by the imaging unit16. The control unit11is assumed to detect the position of the eyes of the user or the line-of-sight direction by using a known line-of-sight detection technique. For example, the control unit11detects the position of the eyes of the user or the line-of-sight direction of the user on the basis of a positional relationship between pupils of the user and a basic point obtained by reflecting infrared light by corneas of the user. Alternatively, on the basis of the position of irises or pupils, the control unit11may detect the position of the eyes of the user or the line-of-sight direction of the user. In addition, the imaging unit16may include a function of detecting the position of the eyes of the user or the line-of-sight direction of the user.

As described above, the position of the eyes of the user or the line-of-sight direction of the user detected from an image including the image40of the eyes of the user imaged by the imaging unit16is applicable to calibration of the HMD10or a line-of-sight tracking function of the user. The calibration of the HMD10is for adjusting a display position of a video in the display unit14at the time of starting up the HMD10, at the time of starting up applications, or the like; for example, the display position of the video can be adjusted so that the video is displayed in the position of the eyes of the user on the display unit14by using the detected position of the eyes of the user. In the line-of-sight tracking function of the HMD10, for example, a line-of-sight tracking can be performed by using the detected line-of-sight direction of the user.

In addition, the image including the image40of the eyes of the user imaged by the imaging unit16may be assumed to be transmitted to an external information processing apparatus via the input/output unit13. In this case, the position of the eyes of the user or the line-of-sight direction of the user is assumed to be detected by using the image including the image40of the eyes of the user received by the external information processing apparatus.

In the first example of the configuration of the HMD10according to the present embodiment illustrated inFIG. 2, a state in which the user wears the HMD10is illustrated. As illustrated inFIG. 2, in the HMD10according to the present embodiment, the display unit14and an optical system17including at least one optical member such as a mirror, a lens, or a prism are disposed in front of the eyes of the user. That is, the optical system17is disposed in front of the eyes of the user and the display unit14is disposed at a front surface of the eyes30of the user through the optical system17. Further, it is assumed that when a distance from the display unit14to the optical system17is X and a distance from the optical system17to the eyes30of the user is Y, the distance Y is shorter than the distance X. In particular, in the HMD10worn by the user, the distance Y tends to become short. In the above-described HMD10according to the present embodiment, video light output from the display unit14passes through the optical system17and is made incident on the eyes30of the user, and thereby the user can view a video displayed on the display unit14. Further, the light-irradiation unit15is disposed between the optical system17and the eyes30of the user and irradiates infrared light onto the eyes30of the user. The imaging unit16is a camera capable of imaging infrared light and is disposed facing to the display unit14between the display unit14and the optical system17. Herein, it is assumed that a vertical distance between the imaging unit16and a straight line incident vertically on the display unit14from the eyes30of the user is H1and a vertical distance between the display unit14and the imaging unit16is L1.

In the HMD10according to the present embodiment illustrated inFIG. 2, the infrared light irradiated onto the eyes30of the user by the light-irradiation unit15is reflected by the eyes30of the user; further, the reflected light passes through the optical system17and is made incident on the display unit14, and thereby the image40of the eyes of the user by the infrared light is reflected in the display unit14. Then, the imaging unit16images the display unit14in which the image40of the eyes of the user by the infrared light is reflected. In addition, the image40of the eyes of the user by the infrared light may be only required to indicate the pupils of the user and the basic point obtained by reflecting the infrared light by the corneas of the user; further, the imaging unit16may be disposed so as to image a portion of the display unit14in which the above-described image40of the eyes of the user is reflected. As described above, in the HMD10according to the present embodiment illustrated inFIG. 2, a photographing angle of the imaging unit16to the image40of the eyes of the user reflected in the display unit14is θ1. It is to be noted that, inFIG. 2, the photographing angle91to a center of the image40of the eyes of the user reflected in the display unit14is illustrated as an example.

Subsequently, a contrast example with the HMD10according to the present embodiment illustrated inFIG. 2will be described.FIG. 3is a schematic diagram illustrating a configuration of an HMD110according to the contrast example. In the HMD110according to the contrast example illustrated inFIG. 3, a display unit114and an optical system117including at least one optical member such as a mirror, a lens, or a prism are disposed in front of the eyes of the user. That is, the optical system117is disposed in front of the eyes of the user and the display unit114is disposed at the front surface of eyes130of the user through the optical system117. Further, a light-irradiation unit115is disposed between the optical system117and the eyes130of the user and irradiates infrared light onto the eyes130of the user. An imaging unit116is a camera capable of imaging infrared light and is disposed facing to the eyes130of the user between the optical system117and the eyes130of the user. In addition, the display unit114, the light-irradiation unit115, the imaging unit116, and the optical system117of the HMD110according to the contrast example illustrated inFIG. 3are assumed to be the same as the display unit14, the light-irradiation unit15, the imaging unit16, and the optical system17of the HMD10according to the present embodiment illustrated inFIG. 2, respectively. Thus, a distance X from the display unit114to the optical system117and a distance Y from the optical system117to the eyes130of the user are assumed to be the same as those of the HMD10according to the present embodiment illustrated inFIG. 2.

In the HMD110according to the contrast example illustrated inFIG. 3, the infrared light irradiated onto the eyes130of the user by the light-irradiation unit115is reflected by the eyes130of the user and the reflected light is made incident on the imaging unit116. As described above, the imaging unit116of the HMD110according to the contrast example is capable of imaging the pupils of the user and the basic point obtained by reflecting the infrared light irradiated by the light-irradiation unit115by the corneas of the user. Further, in the HMD110according to the contrast example illustrated inFIG. 3, a photographing angle of the imaging unit116to the eyes130of the user is θ2. It is to be noted that, inFIG. 3, the photographing angle82to a center of the eyes130of the user is illustrated as an example.

Herein, the HMD10according to the present embodiment illustrated inFIG. 2and the HMD110according to the contrast example illustrated inFIG. 3are compared with each other.

First, in the HMD10according to the present embodiment, the imaging unit16is preferably disposed in a location in which it is easy to image the image40of the eyes of the user reflected in the display unit14and a video displayed on the display unit14by the user is not prevented from being viewed. In the HMD10according to the present embodiment as illustrated inFIG. 2, for example, the imaging unit16is disposed at the end of the optical system17that is a position near to the optical system17. That is, the vertical distance L1between the display unit14and imaging unit16in the HMD10according to the present embodiment is a value approximate to the distance X. Further, the vertical distance H1between the imaging unit16and a straight line incident on the display unit14vertically from the eyes30of the user is a value according to a size of the optical system17and the position of the eyes of the user and is, for example, approximately half of a height of the optical system17.

Subsequently, in the HMD110according to the contrast example, the imaging unit116is preferably disposed in a location in which it is easy to image the eyes130of the user and a video displayed on the display unit114is not prevented from being viewed by the user. In the HMD110according to the contrast example as illustrated inFIG. 3, for example, the imaging unit116is disposed at the end of the optical system117that is a position near to the optical system117. That is, a vertical distance L2between the eyes30of the user and the imaging unit116in the HMD110according to the contrast example is a value approximate to the distance Y. Further, a vertical distance H2between the imaging unit116and a straight line incident on the display unit114vertically from the eyes130of the user is a value according to a size of the optical system117and the position of the eyes of the user and is, for example, approximately half of a height of the optical system117. It is to be noted that, in the HMD110according to the contrast example illustrated inFIG. 3, as the distance Y is shorter and as the size of the optical system117is larger, the photographing angle82of the imaging unit116to the eyes130of the user is shallower and eyelashes, eyelids, or the like of the user become an obstacle to the imaging.

As described above, inFIGS. 2 and 3, the vertical distance H1in the HMD10according to the present embodiment is approximately the same as the vertical distance H2in the HMD110according to the contrast example. Further, the vertical distance L1in the HMD10according to the present embodiment is longer than the vertical distance L2in the HMD110according to the contrast example. Therefore, the photographing angle θ1of the imaging unit16to the image40of the eyes of the user reflected in the display unit14according to the present embodiment is larger than the photographing angle82of the imaging unit116to the eyes130of the user according to the contrast example. As described above, the imaging unit16according to the present embodiment images the display unit14in which the image40of the eyes of the user is reflected, and thereby it is possible to deepen the photographing angle of the imaging unit16to the image40of the eyes of the user and it is easy to photograph the image40of the eyes of the user.

In the above-described example, an example is provided in which the vertical distance H1in the HMD10according to the present embodiment is approximately the same as the vertical distance H2in the HMD110according to the contrast example, and the vertical distance L1in the HMD10according to the present embodiment is longer than the vertical distance L2in the HMD110according to the contrast example; however, the present embodiment is not limited to this example. For example, the vertical distance H1in the HMD10according to the present embodiment may be larger than half of the height of the optical system17. Further, the vertical distance L1in the HMD10according to the present embodiment may be shorter than the distance X or may be shorter than the distance Y. Even in this case, the imaging unit16according to the present embodiment images the display unit14in which the image40of the eyes of the user is reflected, and thereby there is not present an obstacle to the imaging such as the eyelashes or eyelids of the user as in the HMD110according to the contrast example, and therefore it is easy to image the image40of the eyes of the user.

The imaging unit16further images the display unit14in which the image40of the eyes of the user by the infrared light is reflected, and thereby the image40of the eyes of the user can be imaged even during the period in which videos or the like received from entertainment apparatus are displayed on the display unit14. That is, the infrared light is irradiated onto the eyes of the user, and thereby the image40of the eyes of the user can be reflected in the display unit14without obstructing the video displayed on the display unit14. Through this processing, even while the user views the video or the like received from the entertainment apparatus, the control unit11is capable of detecting the position of the eyes of the user or the line-of-sight direction of the user and performing the calibration or the line-of-sight tracking. For example, a line-of-sight input operation can be used as a user input operation to be accepted while the video or the like received from the entertainment apparatus is displayed on the display unit14; further, the entertainment apparatus is capable of performing processing relating to the input operation according to the position of the eyes of the user or the line-of-sight direction of the user.

Further, in the HMD10according to the present embodiment illustrated inFIG. 2, the imaging unit16may be assumed to be a camera capable of imaging visible light. In this case, the imaging unit16is assumed to perform image processing such as filtering processing to an image obtained by imaging the display unit14and thereby extract the image40of the eyes of the user by the infrared light.

Further, in the HMD10according to the present embodiment illustrated inFIG. 2, it may be assumed that the imaging unit16is a camera capable of imaging visible light and further the light-irradiation unit15is not disposed. Even when the light-irradiation unit15is not disposed, reflected light obtained by reflecting visible light by the eyes30of the user passes through the optical system17and is made incident on the display unit14, and thereby the image40of the eyes of the user by the visible light is reflected in the display unit14. Then, the imaging unit16may be assumed to image the display unit14in which the image40of the eyes of the user by the visible light is reflected. Herein, when the imaging unit16images the display unit14in which the image40of the eyes of the user by the visible light is reflected, the imaging unit16preferably images the display unit14during the period in which the video or the like received from the entertainment apparatus is not displayed on the display unit14.

FIG. 4is a schematic diagram illustrating a second example of a configuration of the HMD10according to the present embodiment. The HMD10according to the present embodiment illustrated inFIG. 4is obtained by making different a position of the light-irradiation unit15of the HMD10according to the present embodiment illustrated inFIG. 2. The light-irradiation unit15of the HMD10according to the present embodiment illustrated inFIG. 4is disposed between the display unit14and the optical system17and irradiates the infrared light called infrared laser onto the display unit14. The other configurations are similarly to those of the HMD10according to the present embodiment illustrated inFIG. 2, and therefore redundant descriptions are omitted herein.

In the HMD10according to the present embodiment illustrated inFIG. 4, the infrared light irradiated onto the display unit14by the light-irradiation unit15is reflected by the display unit14; further, the reflected light passes through the optical system17and is irradiated onto the eyes30of the user. Then, the infrared light irradiated onto the eyes30of the user is reflected by the eyes30of the user; further, the reflected light passes through the optical system17again and is made incident on the display unit14, and thereby the image40of the eyes of the user by the infrared light is reflected in the display unit14. Then, the imaging unit16images the display unit14in which the image40of the eyes of the user is reflected. As described above, the reflected light obtained by reflecting the infrared light irradiated onto the display unit14is irradiated onto the eyes30of the user and thereby the infrared light is made incident on the eyes30of the user from the front side. Thus, since the image40of the eyes of the user is easily reflected in the display unit14, the imaging unit16easily images the display unit14in which the image40of the eyes of the user is reflected. Thus, an accuracy of detection in the position of the eyes of the user or in the line-of-sight direction of the user through the control unit11is improved.

In addition, the configuration of the HMD10illustrated inFIGS. 2 and 4is consistently one example and is not limited to this example. In the above-described example, inFIGS. 2 and 4, an example is provided in which the light-irradiation unit15and the imaging unit16are disposed on the upper side of the HMD10; further, for example, the light-irradiation unit15and the imaging unit16may be disposed on the lower side of the HMD10or may be disposed on the side surface side of the HMD10. These dispositions may be appropriately set in accordance with characteristics of the display unit14or the optical system17, the distance X from the display unit14to the optical system17, the distance X2from the optical system17to the eyes30of the user, or the like.

Modification Example

FIG. 5is a schematic diagram illustrating a first modification example of the configuration of the HMD10according to the present embodiment.FIG. 5illustrates a state in which the user wears the HMD10. In the HMD10according to the modification example illustrated inFIG. 5, the optical system17is disposed in front of the eyes of the user and the imaging unit16is disposed at the front surface of the eyes30of the user through the optical system17. The optical system17includes a mirror27that reflects visible light and transmits infrared light and is disposed between the imaging unit16and the eyes30of the user. The display unit14is disposed so that video light output from the display unit14is reflected by the mirror27and is made incident on the eyes30of the user. The light-irradiation unit15is disposed between the optical system17and the eyes30of the user and irradiates the infrared light onto the eyes30of the user. The imaging unit16is assumed to be an infrared camera capable of imaging the infrared light.

In the HMD10according to the modification example illustrated inFIG. 5, the infrared light irradiated onto the eyes30of the user by the light-irradiation unit15is reflected by the eyes30of the user, and the reflected light is transmitted through the mirror27and is made incident on the imaging unit16. This processing permits the imaging unit16to image the eyes30of the user to the eyes30of the user from the front side.

FIG. 6is a schematic diagram illustrating a second modification example of the configuration of the HMD10according to the present embodiment. The HMD10according to the modification example illustrated inFIG. 6is obtained by making different the position of the light-irradiation unit15of the HMD10according to the modification example illustrated inFIG. 5. The light-irradiation unit15of the HMD10according to the modification example illustrated inFIG. 6is disposed in front of the eyes of the user through the optical system17. The other configurations are similarly to those of the HMD10according to the modification example illustrated inFIG. 5, and therefore redundant descriptions are omitted herein.

In the HMD10according to the modification example illustrated inFIG. 6, the infrared light irradiated by the light-irradiation unit15is transmitted through the mirror27and is irradiated onto the eyes30of the user. Then, the infrared light irradiated onto the eyes30of the user is reflected by the eyes30of the user; further, the reflected light is transmitted through the mirror27and is made incident on the imaging unit16. This processing permits the light-irradiation unit15to irradiate the infrared light onto the eyes30of the user from the front side, and permits the imaging unit16to image the eyes30of the user to the eyes30of the user from the front side.