TWI490547B - Autofocus head mounted display - Google Patents

Description

Auto focus head mounted display

The present invention relates to a head mounted display, and more particularly to a head mounted display that automatically adjusts the focus.

With the development of display devices, the size and weight of display devices have progressed toward miniaturization. In recent years, Head Mount Display (HMD) has been developed as an image display for virtual reality (VR) systems to be worn on the user's head, and the field of application is becoming more and more extensive. The head-mounted display places the display element in front of the user's eyes in the form of glasses or a helmet, and projects a virtual image on the user's eyes through the distance to generate a wide-angle view, and allows the user to receive image information anywhere.

However, the general head-mounted display is a fixed-focus design (that is, displaying a virtual image at a fixed distance), and this design is liable to cause the user to feel tired due to long-term focusing on the virtual image. When the head-mounted display is opaque, if the position of the scene and the virtual image is very different, the difference in focus adjustment of the human eye will also become large and affect the reaction time.

In view of the above problems of the prior art, one of the objects of the present invention is to provide an autofocus head mounted display comprising at least a light source, a first polarization beam splitter, a display element, a second polarization beam splitter, a wave plate, and a mirror. And adjustable optics.

The light source is used to provide light, and the first polarizing beam splitter is disposed on the light transmission path for reflecting light.

In other words, the display component receives the light reflected by the first polarization beam splitter to project the image light through the first polarization beam splitter. The polarization direction of the light is orthogonal to the polarization direction of the image light projected by the display element, and the display element may be, for example, a liquid crystal on silicon (LCoS) display element.

In other words, the second polarization beam splitter and the wave plate are disposed on the transmission path of the image light. The image light penetrating the first polarization beam splitter sequentially penetrates the second polarization beam splitter and the wave plate, and the image light is reflected by the mirror, so that the image light penetrates the wave plate again, so that the second polarization beam splitter will The image light is reflected to the user's eyes.

The aforementioned wave plate may be, for example, a Quarter Wavelength Plate. The aforementioned mirror can be, for example, a concave mirror (Concave Mirror).

In other words, the adjustable optical component is disposed between the first polarization beam splitter and the second polarization beam splitter to adjust the convergence or divergence of the image light. The adjustable optical component can be, for example, a liquid crystal lens or a combination of a positive lens and a negative lens. Therefore, the adjustable optical component can not only adjust the focal length of the head-mounted display during production to compensate for errors of other optical components, but also compensate the position of the virtual image displayed by the user of myopia or hyperopia.

In addition, the auto-focusing head-mounted display further includes a charge-coupled device (CCD) electrically connected to the display element to receive the light of the scene, and convert the light of the scene into image light by the display element. Wherein, the light of the scene is reflected by the second polarization beam splitter to the first polarization beam splitter, The light of the scene is further reflected by the first polarizing beam splitter to the charge coupled element.

In addition, the adjustable optical component can detect the convergence or divergence of the image light by, for example, detecting the distance between the scene and the user by using an infrared distance detector; or can adjust the image by determining the motion of the user, for example, by a gyroscope. Convergence or divergence of light. Thereby, the position of the virtual image displayed by the user can be adjusted to avoid the tiredness of the user's eyes.

In view of the above, an autofocus head mounted display in accordance with the present invention may have one or more of the following advantages:

(1) The autofocus head mounted display of the present invention utilizes an adjustable optical component to adjust the focal length of the head mounted display during production to compensate for errors in other optical components.

(2) The autofocus head mounted display of the present invention utilizes an adjustable optical component to adjust the focal length of the head mounted display during production to compensate for the position of the virtual image displayed by the user of myopia or hyperopia.

(3) The autofocus head-mounted display of the present invention utilizes an adjustable optical element to adjust the position of the virtual image displayed by the user in use to avoid fatigue in the eyes of the user.

For a better understanding and understanding of the technical features and the efficacies of the present invention, the preferred embodiments and the detailed description are as follows.

10‧‧‧Light source

11‧‧‧Light

20‧‧‧First polarization beam splitter

30‧‧‧Display components

31, 32‧‧‧ image light

40‧‧‧Second polarization beam splitter

50‧‧‧ wave board

60‧‧‧Mirror

70‧‧‧ User's eyes

80‧‧‧ liquid crystal lens

81‧‧‧ positive lens

82‧‧‧negative lens

90‧‧‧Electrical coupling components

100‧‧‧ Scenery

110‧‧‧Light of the scenery

1 is a schematic view of a first embodiment of an autofocus head mounted display of the present invention.

2 is a schematic view showing a second embodiment of the autofocus head mounted display of the present invention.

Figure 3 is a schematic view showing a third embodiment of the autofocus head mounted display of the present invention.

The embodiments of the auto-focusing head-mounted display according to the present invention will be described below with reference to the related drawings. For ease of understanding, the same components in the following embodiments are denoted by the same reference numerals.

Please refer to FIG. 1. FIG. 1 is a schematic view showing a first embodiment of the autofocus head mounted display of the present invention. The autofocus head mounted display includes at least a light source 10, a first polarization beam splitter 20, a display element 30, a second polarization beam splitter 40, a wave plate 50, a mirror 60, and a tunable optical element.

The light source 10 is used to provide the light 11 , and the first polarizing beam splitter 20 is disposed on the transmission path of the light 11 for reflecting the light 11 . The light source 10 can be, for example, a Light-Emitting Diode (LED), and the light 11 can be, for example, polarized polarized light, such as P-polarized or S-polarized.

In other words, the display element 30 receives the light 11 reflected by the first polarizing beam splitter 20 to project the image light 31 through the first polarizing beam splitter 20. The image light 31 projected by the display element 30 can be, for example, polarized light in the S polarization direction or polarized light in the P polarization direction.

The polarization direction of the light ray 11 described above is orthogonal to the polarization direction of the image ray 31 projected by the display element 30. The aforementioned display element 30 can be, for example, a reflective liquid crystal on silicon (LCoS) display element.

In other words, the second polarization beam splitter 40 and the wave plate 50 are disposed on the transmission path of the image light 31. The wave plate 50 is preferably a Quarter Wavelength Plate.

When the image light rays 31 penetrating the first polarization beam splitter 20 sequentially penetrate the second polarization beam splitter 40 and the wave plate 50, the image light rays 31 may be, for example, circularly polarized light, and then by the mirror 60. The image light 31 is reflected. The mirror 60 can be, for example, a Concave Mirror, which is used to enlarge the virtual image seen by the user's eye 70.

Then, after the mirror 60 reflects the image light 31, the reflected image light 32 penetrates the wave plate 50 again, so that the polarization direction of the image light 32 after penetrating the wave plate 50 again is compared with the image projected by the display element 30. The polarization direction of the light 31 is rotated by 90 degrees to reflect the image light 32 to the user's eye 70 by the second polarization beam splitter 40. The polarization direction of the image light 31 is orthogonal to the polarization direction of the reflected image light 32.

In other words, the adjustable optical component is disposed between the first polarization beam splitter 20 and the second polarization beam splitter 40 for adjusting the convergence or divergence of the image light 31. The adjustable optical element can be, for example, a liquid crystal lens (Liquid Crystal Lens) 80. Therefore, the adjustable optical element can not only adjust the focal length of the head mounted display during production to compensate for errors of other optical components, but also compensate for the position of the virtual image seen by the eye 70 of the user of myopia or hyperopia.

Please refer to FIG. 2, which is a schematic view of a second embodiment of the autofocus head mounted display of the present invention.

The auto-focusing head-mounted display can further comprise, for example, a charge-coupled component A (Charge-coupled Device, CCD) 90 is electrically connected to the display element 30. The light 110 of the scene 100 is reflected by the second polarization beam splitter 40 to the first polarization beam splitter 20, and the light 110 of the scene 100 is further reflected by the first polarization beam splitter 20 to the charge coupled element 90.

In other words, after the electrical coupling element receives the light 110 of the scene 100, the light 110 of the scene 100 can be converted into an electrical signal to the display element 30. After receiving the electrical signal, the display element 30 can view the object 100 as image light. 31 projected. Then, the image light rays 31 sequentially penetrate the liquid crystal lens 80, the second polarization beam splitter 40, and the wave plate 50, and the image light rays 31 are reflected by the mirror 60, so that the reflected image light rays 32 penetrate the wave plate 50 again to Image light 32 is reflected by the second polarizing beam splitter 40 to the user's eye 70.

The auto-focusing head-mounted display can further detect the distance between the scene 100 and the user by using an infrared distance detector, for example, as the liquid crystal lens 80 adjusts the convergence or divergence of the image light 31; or The gyroscope judges the user's action as the basis for adjusting the convergence or divergence of the image light 31 as the liquid crystal lens 80. In this way, the electric field intensity of the liquid crystal lens 80 can be controlled according to the signal of the infrared distance detector or the gyroscope, and the arrangement of the liquid crystals can be changed to generate a corresponding refractive index distribution, thereby automatically adjusting the focal length of the head mounted display. .

For example, the auto-focusing head-mounted display can use the gyroscope to determine the horizontal angle to adjust the focal length of the auto-focusing head-mounted display. When the user watches the distant scene 100, the user's eyes and The ground system is horizontal, so that the signal of the gyroscope can be used as the basis for adjusting the convergence or divergence of the image light 31 by the liquid crystal lens 80, so that the position of the virtual image seen by the user is displayed at a distance.

On the other hand, when the user looks down at the newspaper or magazine, the user's eyes and the ground are at an angle, so that the signal of the gyroscope can be used as the basis for adjusting the convergence or divergence of the image light 31 by the liquid crystal lens 80, so that the user The virtual image seen is presented in a closer position. Thereby, the position of the virtual image displayed by the user can be adjusted to prevent the user's eyes from being tired due to long-term focusing on the virtual image of the same position.

In addition, through the disclosure of the present invention, those having ordinary knowledge in the technical field of the present invention should be able to clearly understand how the gyroscope or the infrared distance detector is applied to the auto-focusing head-mounted display, and therefore will not be described herein.

Please refer to FIG. 3, which is a schematic diagram of a third embodiment of the autofocus head mounted display of the present invention. The third embodiment differs from the second embodiment only in the adjustable optical element.

The adjustable optical component is disposed between the first polarization beam splitter 20 and the second polarization beam splitter 40 for adjusting the convergence or divergence of the image light 31. The adjustable optical component can be, for example, a combination of a positive lens (Last) Lens 81 and a negative lens (Negative Lens) 82.

The combination of the positive lens 81 and the negative lens 82 can also detect the distance between the scene 100 and the user, for example, by the infrared distance detector, and adjust the convergence or divergence of the image light 31 as the positive lens 81 and the negative lens 82; For example, the gyro determines the motion of the user, and the positive lens 81 and the negative lens 82 adjust the basis for convergence or divergence of the image light 31. In this way, the distance between the positive lens 81 and the negative lens 82 can be controlled according to the signal of the infrared distance detector or the gyroscope to adjust the convergence or divergence of the image light 31, thereby automatically adjusting the focal length of the head mounted display.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

10‧‧‧Light source

11‧‧‧Light

20‧‧‧First polarization beam splitter

30‧‧‧Display components

31, 32‧‧‧ image light

40‧‧‧Second polarization beam splitter

50‧‧‧ wave board

60‧‧‧Mirror

70‧‧‧ User's eyes

80‧‧‧ liquid crystal lens

Claims (7)

An autofocus head mounted display comprising: a light source for providing a light; a first polarizing beam splitter disposed on the light transmission path for reflecting the light; a display element receiving the first light a light reflected by a polarization beam splitter to project an image light to penetrate the first polarization beam splitter; a second polarization beam splitter disposed on the transmission path of the image light; a wave plate is also disposed in the image light In the transmission path, the image light sequentially penetrates the second polarization beam splitter and the wave plate, and the image light is reflected by a mirror, so that the image light penetrates the wave plate again, by the first a polarizing beam splitter reflects the image light to a user's eye; an adjustable optical component is disposed between the first polarizing beam splitter and the second polarizing beam splitter for adjusting the convergence or divergence of the image light And a charge-coupled device (CCD) electrically connected to the display element to receive a light of a scene, and the light of the scene is turned by the display element And the light of the scene is reflected by the second polarization beam splitter to the first polarization beam splitter to further reflect the light of the scene to the charge coupling element by the first polarization beam splitter And wherein the adjustable optical component detects the convergence of the image light by the infrared distance detector to detect the distance between the scene and the user. The auto-focusing head-mounted display of claim 1, wherein the adjustable optical component further determines the movement of the user by a gyroscope to adjust the convergence or divergence of the image light. The autofocus head mounted display of claim 1, wherein the adjustable optical component is a liquid crystal lens. The autofocus head mounted display of claim 1, wherein the adjustable optical component is a combination of a positive lens and a negative lens. The auto-focusing head-mounted display of claim 1, wherein the display element is a liquid crystal on silicon (LCoS) display element. The autofocus head mounted display of claim 1, wherein the wave plate is a Quarter Wavelength Plate. The autofocus head mounted display of claim 1, wherein the mirror is a Concave Mirror.