JPH06317759A - Head-mounted type display - Google Patents

Abstract

PURPOSE:To provide a head-mounted type display where the efficiency of receiving light from a video display element and the efficiency of receiving external light are improved. CONSTITUTION:This display is provided with a display device 1, a 1st prism 2 having a 1st surface 3 on which video light from the display device 1 is made incident and a 2nd surface 5 on which the external light is made incident, a 2nd prism 6 having an incident surface 7 on which the video light is made incident or the external light is made incident, an optical layer provided between both prisms 2 and 6 and having lower refractive index than that of the 2nd prism 6, and a concave mirror 8 reflecting the video light. The 1st prism 2, the 2nd prism 6 and the optical layer are constituted so that they can be integrally turned, thereby receiving the video light and the external light without the loss of light quantity in a state where a display device is attached.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head mounted display which is mounted on the head and used to enjoy a large-screen image by one person indoors and outdoors.

[0002]

2. Description of the Related Art Various display devices such as a helmet type device, a goggle type device and a spectacle type device have been proposed. These are configured so that an observer can observe an image and enjoy sound through an optical means incorporated inside the apparatus in a state of being unaffected by external light. These display devices are capable of stereoscopically displaying images and stereoscopically receiving sound, and are attracting attention as new image devices mainly for young people.

By the way, it has been proposed that the above-mentioned display device is an optical system having a switching means so that the outside world can be seen in order to meet the demand when it is necessary to grasp the surroundings in the mounted state. ing.
For example, USP 4,969,724 discloses an optical system as shown in FIG. This is because light from an image display device such as a CRT is made incident on the first prism 30 at an angle larger than the critical angle, and after being totally internally reflected, the first half prism 30 is partially reflected by the spherical half mirror 31. The light is transmitted through the inner surface and the second prism 32 to reach the eyes of the observer (solid line indicates the traveling direction of light).

[0004]

However, in the above-mentioned conventional example, the light incident on the first prism 30 is partially reflected by the spherical half mirror 31 and reaches the observer's eye.
As shown by the broken line, the external light also partially passes through the spherical half mirror 31 and reaches the observer's eye. In this way, the light from the image display element and the external light reach the eyes of the observer at the same time, which causes a loss of the amount of light from the image display element. Since the mirror 31 is used, the amount of light from the image display element or the amount of external light is halved, resulting in poor light receiving efficiency.

The present invention has been proposed to solve the above-mentioned problems, and in a head-mounted display device which is configured so that the display device can grasp the surrounding condition in the mounted state, It is an object of the present invention to provide a head-mounted display that improves the light receiving efficiency and the external light receiving efficiency.

[0006]

In order to achieve the above object, the present invention provides an image generating means, a first surface on which image light from the image generating means is incident and a second surface on which external light is incident. Is provided between the first prism and the second prism, and the second prism having a surface on which the image light from the image generation unit is incident or the external light is incident. An optical layer having a refractive index lower than that of the prism, a concave mirror for reflecting the image light from the image generating means, and an optical layer provided between the first prism and the second prism. The prism body has a rotatable structure.

[0007]

The image light is configured so as to be totally reflected within the optical element and reach the eyes of the observer without being interrupted by the external light without passing through the half mirror. Since the outside light reaches the eyes of the observer by switching and using the optical elements, both the image light and the outside light can be received without loss of light amount.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an optical system according to a first embodiment of the present invention, in which FIG. 1A shows an optical path diagram for observing an electronic image, and FIG. 1B shows an optical system in the state of FIG. 1A. FIG. 6 is an optical path diagram when the external image is observed by rotating the system. A first prism 2 is provided in a direction in which image light is emitted from the display device 1 which is an image generating means. The first prism 2 has a first surface 3 on which image light from the display device 1 is incident, an emission surface 4 on which image light is emitted, and a second surface 5 on which external light is transmitted.
Have.

A second prism 6 is provided in the direction in which the image light is emitted from the first prism 2. The second prism 6 has an incident surface 7 that allows the image light to be incident from the first prism 2 or that transmits external light, an eccentric concave mirror 8 that reflects the incident image light, and whether to emit the image light. Alternatively, it has an emission surface 9 for emitting external light. In addition,
The emission surface 9 and the second surface 5 of the first prism 2 are configured to be parallel to each other. In addition, an air layer 10 having a lower refractive index than the second prism 6 is interposed between the first prism 2 and the second prism 6. The display device 1, the first prism 2, the air layer 10, and the second prism 6 can be integrally rotated while maintaining the mutual positional relationship.

Next, the operation of the first embodiment constructed as above will be described. When the image light from the display device 1 is received and the observer views the image, the orientation of the optical system is set as shown in FIG. 1A. Then, the display device 1
Image light from is incident on the first surface 3 of the first prism 2. The image light transmitted through the first prism 2 is
The light is refracted by the air layer 10 from the exit surface 4 and enters the entrance surface 7 of the second prism 6. The incident light is reflected by the concave mirror 8, is incident on the incident surface 7 again at an angle equal to or greater than the critical angle, is totally reflected, is emitted from the emitting surface 9, and reaches the observer's eye. In this way, the image light can reach the eyes of the observer without being disturbed by the external light and without causing the loss of the image light.

Next, the case of observing the external image will be described.
In this case, the orientation of the optical system is set as shown in FIG. 1B (the broken line shows the original state, and the solid line shows the state rotated in the arrow direction). Then, the outside world image is incident on the second surface 5 of the first prism 2, is transmitted through the inside of the first prism 2, and the outside world image is refracted by the air layer 10 from the exit surface 4 and enters the second prism 6. It is incident on the surface 7. Then, it is emitted from the emission surface 9 and reaches the eyes of the observer. In this way, the light enters the respective surfaces of the first prism 2 and the second prism 6 at an angle equal to or less than the critical angle, follows the optical path different from the optical path of the image light from the display device 1, and interferes with the image light. It is possible to reach the observer's eyes without causing any loss of external light without being reflected.

In this embodiment, the emission surface 9 and the second surface 5 of the first prism 2 are arranged to be parallel to each other, but they do not necessarily have to be parallel to each other. Further, in this embodiment, the concave mirror 8 is formed integrally with the second prism 6, but it is not always necessary to form it. Second
It may be independently provided in the vicinity of the second prism 6 as long as the image light incident on the prism 6 is totally reflected and then again incident on the incident surface 7 and totally reflected. Further, in this embodiment, the display device 1, the first prism 2,
The air layer 10 and the second prism 6 can rotate integrally with each other while maintaining the mutual positional relationship, but the display device 1 does not rotate integrally. Good. The integrated structure as in the present embodiment has an advantage that the entire structure of the optical system becomes compact.

2 and 3 show a second embodiment of the present invention. Of these, FIG. 2 shows a state in which an electronic image is observed (A) and a state in which an external image is observed (B), and a head-mounted display is attached to the head of each observer 11. It is in a state. An LCD (liquid crystal display) that receives a signal from the image generation device 12 is disposed so as to be located on both side faces of the observer's face, and an optical system 16 according to the present invention is provided via a relay lens 14 and a triangular prism 15. The image light is made to enter. In addition, the external light enters the eyes of the observer 11 only through the optical system 16 according to the present invention.

The optical system 16 arranged in front of the observer's eyes is
It has a first prism 17 and a second prism 18. The first prism 17 has a surface a on which image light is incident, a surface b on which image light and external light are emitted, and a surface c on which external light is incident. The second prism 18 has a surface d on which the image light and the external light are incident, a surface e on which the image light and the external light are emitted, and a surface f on which the image light is reflected. The c-plane and the e-plane are formed parallel to each other. Also,
Between the first prism 17 and the second prism 18,
An air layer 19 similar to that of the first embodiment is interposed. Then, the first prism 17 that sandwiches the air layer 19
The second prism 18 and the second prism 18 are configured to be rotatable in the direction of the paper surface, and by rotating from the state of FIG. 2A to the state of FIG. 2B, the observation of the electronic image can be switched to the observation of the external image. Has become.

Next, the operation of the present embodiment configured as described above will be described. First, to observe the electron image, LC
The light from D13 is made incident on the triangular prism 15 via the relay lens 14 and internally reflected so that the optical path is changed and made incident on the first prism 17. The incident light passes through the first prism 17, is refracted by passing through the air layer 19, and then enters the second prism 18. Incident light is reflected by the f-plane, which is a concave mirror that is eccentric, is incident on the d-plane at an angle equal to or greater than the critical angle, and is totally reflected. .

On the other hand, when observing the external image, the first prism 17 and the second prism 18 that sandwich the air layer 19 are provided.
And are rotated in the direction of the paper surface to bring them to the state of FIG. 2B. That is, the c-plane and the e-plane are set to be parallel to both eyes. Then, the external image enters the c-plane of the first prism 17, passes through the b-plane, the air layer 19, enters the d-plane of the second prism 18, and exits from the e-plane to both eyes of the observer without loss of light quantity. reach. It goes without saying that both the electronic image and the external light reach the eyes of the observer through the transparent member 20a forming the goggle type cover 20 (the external light is transmitted through the member 20b. It comes into the cover 20). Figure 3
FIG. 3 is a device perspective view showing a state in which an electronic image is being observed according to the present embodiment.

As described above, according to the present invention, the light from the image generating means passes through the first prism, passes through the air layer, and enters the second prism. The light incident on the second prism is reflected by the concave mirror, then enters the reflecting surface at an angle larger than the critical angle, and is totally reflected to reach the observer's eye, so that the loss of the light quantity can be prevented. . Also, external light can be made to reach the observer's eyes without loss of light quantity by switching and using a predetermined optical element.

[Brief description of drawings]

FIG. 1 shows an optical system related to a head mounted display according to a first embodiment of the present invention and a switching state of the optical system.

FIG. 2 is a plan view showing a head mounted display according to a second embodiment of the present invention and a state in which an optical system is switched.

FIG. 3 is a perspective view showing a head-mounted display according to a second embodiment of the present invention.

FIG. 4 shows an optical system of a conventional example.

[Description of Reference Signs] 1 display device 2 first prism 3 first surface 4 exit surface 5 second surface 6 second prism 7 entrance surface 8 concave mirror 9 exit surface 10 air layer

Claims (1)

[Claims] 1. An image light from the image generating means, a first prism having a first surface on which image light from the image generating means is incident and a second surface on which external light is incident, and image light from the image generating means. Having a surface on which light is incident or on which external light is incident
A prism, an optical layer provided between the first prism and the second prism and having a refractive index lower than that of the second prism, and a concave mirror for reflecting the image light from the image generating means. A head-mounted display characterized in that a prism body having the first prism, the second prism, and an optical layer provided between the first prism and the second prism is configured to be rotatable.