CN112147787B

CN112147787B - Augmented reality heads-up display

Info

Publication number: CN112147787B
Application number: CN202011179737.6A
Authority: CN
Inventors: 李冠勋
Original assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Current assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Priority date: 2020-10-29
Filing date: 2020-10-29
Publication date: 2022-08-09
Anticipated expiration: 2040-10-29
Also published as: CN112147787A; TWI739644B; TW202217395A

Abstract

The invention provides an augmented reality head-up display, which comprises a display device and a light path mirror group with an electric control liquid crystal polaroid. The light path mirror group changes the light path of the light emitted from the display device by switching the electrified state and the non-electrified state of the electric control liquid crystal polaroid, so that a plurality of images provided by the display device form virtual images at different positions, and a user can see the virtual images simultaneously.

Description

Augmented reality heads-up display

Technical Field

The present invention relates to a Head Up Display (HUD), and more particularly, to an Augmented Reality (AR) head up display.

Background

A head-up display is a flight assist device commonly used in aircraft. The head-up display can project the flight information to the front of the windshield, so that the pilot can see the flight information without lowering the head, the attention interruption is avoided, and the safety is improved. Some automobile manufacturers have started to provide heads-up displays in automobiles because of their convenience and the ability to improve safety. The head-up display can project information such as speed, rotating speed, navigation and the like of the automobile to the front of the windshield, so that the driver can obtain the automobile information without lowering head, and the driving safety is improved. In order to combine images with real road conditions, augmented reality heads-up displays have become a popular research direction.

In order to achieve the augmented reality effect, the current augmented reality head-up display requires two or more display devices to provide a plurality of images, and further forms a plurality of virtual images at the remote end and the near end. However, the more display devices, the more the display devices are.

Disclosure of Invention

The present invention is directed to an augmented reality head-up display, which uses a display device to form a plurality of virtual images at a plurality of positions.

According to the invention, an augmented reality head-up display comprises a display device and an optical path lens group. The display device emits a light ray, and the light path mirror group is arranged on a light path of the light ray. The light path mirror group comprises an electric control liquid crystal polaroid and a reflector. The electrically controlled liquid crystal polarizer is disposed on the light path. The reflector is arranged on the light path and positioned between the electric control liquid crystal polaroid and the display device, and reflects the light rays from the display device to the electric control liquid crystal polaroid. During a first time period, the electrically controlled liquid crystal polarizer reflects the light rays from the mirror to form a first virtual image at a first location. During a second time period, the light rays from the mirror penetrate the electrically controlled liquid crystal polarizer to form a second virtual image at a second location.

According to the invention, an augmented reality head-up display comprises a display device and an optical path lens group. The display device emits light rays, and the light path mirror group is arranged on a light path of the light rays. The light path mirror group comprises an electric control liquid crystal polaroid and a reflector. The electrically controlled liquid crystal polarizer and the reflector are both disposed on the light path, and the electrically controlled liquid crystal polarizer is located between the reflector and the display device. In a first time period, the electrically controlled liquid crystal polarizer reflects light from the display device, and the mirror reflects the light from the electrically controlled liquid crystal polarizer to form a first virtual image at a first location. During a second time period, the light rays from the display device penetrate the electrically controlled liquid crystal polarizer to form a second virtual image at a second location.

According to the invention, an augmented reality head-up display comprises a display device and an optical path lens group. The display device emits light rays, and the light path mirror group is arranged on a light path of the light rays. The optical path lens group comprises a first electric control liquid crystal polaroid and a second electric control liquid crystal polaroid. The first electrically controlled liquid crystal polarizer and the second electrically controlled liquid crystal polarizer are both in the light path, and the second electrically controlled liquid crystal polarizer is located between the first electrically controlled liquid crystal polarizer and the display device. In a first time period, the first electrically controlled liquid crystal polarizer reflects the light rays from the display device, and the second electrically controlled liquid crystal polarizer reflects the light rays from the first electrically controlled liquid crystal polarizer to form a first virtual image at a first location. In a second time period, the first electrically controlled liquid crystal polarizer reflects the light rays from the display device, and the light rays from the first electrically controlled liquid crystal polarizer penetrate the second electrically controlled liquid crystal polarizer to form a second virtual image at a second location. During a third time period, the light rays from the display device penetrate through the first electrically controlled liquid crystal polarizer to form a third virtual image at a third location.

The augmented reality head-up display of the invention can generate a plurality of virtual images at a plurality of positions only by one display device, so the augmented reality head-up display of the invention has smaller volume and lower cost.

Drawings

Fig. 1 shows a first embodiment of an augmented reality head-up display according to the present invention.

FIG. 2 shows an embodiment of an electrically controlled liquid crystal polarizer.

Figure 3 shows an embodiment when the electrically controlled liquid crystal polarizer is not energized.

Figure 4 shows an embodiment when the electrically controlled liquid crystal polarizer is energized.

FIG. 5 shows an embodiment of the display device of FIG. 1 outputting two different images.

Fig. 6 shows a second embodiment of an augmented reality head-up display according to the present invention.

Fig. 7 shows a third embodiment of an augmented reality head-up display according to the present invention.

FIG. 8 shows an embodiment of the display device of FIG. 7 outputting three different images.

Reference numerals:

an augmented reality heads-up display

12.. a display device

Optical path lens group

Reflector mirror

An electrically controlled liquid crystal polarizer

A polarization rotator

1822

1824

1826. liquid crystal cell

A reflective polarizer

A human eye

A windshield

Augmented reality heads-up display

Display device

Optical path lens group

An electrically controlled liquid crystal polarizer

A polarization rotator

364.. reflective polarizer

A reflector

Augmented reality heads-up display

Display device

Optical path lens group

A first electrically controllable liquid crystal polarizer

462

464

A second electrically controllable liquid crystal polarizer

482

484

A

Image a'

A second virtual image

Image of

C

Image C

Light ray

LP.. polarization direction

LS.. polarization direction

Optical axis of RPP

Detailed Description

Fig. 1 shows a first embodiment of an augmented reality head-up display according to the present invention. In fig. 1, an augmented reality head-up display 10 includes a display device 12 and an optical lens assembly 14. The display device 12 is configured to emit a light L1 to the optical path assembly 14 to form a first virtual image a or a second virtual image B in front of the windshield 22, where the light L1 may be an image, and the light L1 is an S-polarized light or a P-polarized light. In general, the polarization direction LS of S-polarized light is the vertical direction, and the polarization direction LP of P-polarized light is the horizontal direction. The display device 12 may be, but is not limited to, a display or a projection device. Light path mirror group 14 sets up in on the light path, light path mirror group 14 can change the light path is in order to project light L1 different positions, and then forms first virtual image A or forms second virtual image B at the second position before windshield 22 at the first position before windshield 22. The optical lens assembly 14 includes a reflector 16 and an electrically controlled liquid crystal polarizer 18. A mirror 16 and an electrically controlled liquid crystal polarizer 18 are both disposed in the light path, and the mirror 16 is positioned between the electrically controlled liquid crystal polarizer 18 and the display device 12. The mirror 16 reflects the light L1 from the display device 12. Light ray L1 reflected by mirror 16 may pass through electrically controlled liquid crystal polarizer 18 or be reflected by electrically controlled liquid crystal polarizer 18.

Figure 2 shows an embodiment of an electrically controllable liquid crystal polarizer 18. The electrically controlled liquid crystal polarizer 18 includes a polarization rotator 182 and a reflective polarizer 184. The polarization rotator 182 has an incident surface 1822, an exit surface 1824, and a liquid crystal cell 1826. Liquid crystal cell 1826 is sandwiched between entrance surface 1822 and exit surface 1824, and electrodes, such as but not limited to indium tin oxide transparent electrodes, are disposed on entrance surface 1822 and exit surface 1824, and an external control voltage module (not shown) applies a voltage to the electrodes, which causes liquid crystal molecules in liquid crystal cell 1826 to rotate to a predetermined alignment direction, thereby switching the state of the electrically controlled liquid crystal polarizer that allows polarized light to pass or reflect. The reflective polarizer 184 is disposed on the exit surface 1824 side of the polarization rotator 182 and attached to the exit surface 1824, and the reflective polarizer 184 has an optical axis RPP. When the polarization direction of light ray L1 emerging from exit surface 1824 is parallel to the optical axis RPP of the reflective polarizer 184, light ray L1 will pass through the reflective polarizer 184. When the polarization direction of the light ray L1 emerging from the exit surface 1824 is perpendicular to the optical axis RPP of the reflective polarizer 184, the light ray L1 will be reflected by the reflective polarizer 184.

For easier understanding, the non-energized state and the energized state of the electrically controlled liquid crystal polarizer 18 will be described in one embodiment. Assuming that the light L1 emitted from the display device 12 is P-polarized light and the optical axis RPP of the reflective polarizer 184 is horizontal, when the electrically controlled liquid crystal polarizer 18 is not energized, the liquid crystal molecules in the liquid crystal cell 1826 will not rotate, and as shown in fig. 3, after the light L1 enters the liquid crystal cell 1826 from the incident plane 1824, the polarization direction LP of the light L1 will not be changed, so the polarization direction LP of the light L1 emitted from the exit plane 1824 is parallel to the optical axis RPP of the reflective polarizer 184, and thus can penetrate through the reflective polarizer 184. In other words, when electronically controlled liquid crystal polarizer 18 is not energized, light L1 exiting display device 12 is able to pass through electronically controlled liquid crystal polarizer 18 because the polarization direction LP of light L1 exiting exit surface 1824 is parallel to the optical axis RPP of reflective polarizer 184. When electrically controlled liquid crystal polarizer 18 is turned on, liquid crystal molecules in liquid crystal cell 1826 are rotated, as shown in fig. 4, after light L1 enters liquid crystal cell 1826 from incident surface 1824, light L1 changes from P polarized light to S polarized light, i.e., from polarization direction LP to polarization direction LS, so that polarization direction LS of light L1 exiting from exit surface 1824 is perpendicular to optical axis RPP of reflective polarizer 184, resulting in reflective polarizer 184 reflecting light L1 exiting from exit surface 1824. In other words, when the electrically controlled liquid crystal polarizer 18 is energized, the polarization direction LS of the light ray L1 exiting the exit surface 1824 is perpendicular to the optical axis RPP of the reflective polarizer 184, and therefore the light ray L1 exiting the display device 12 is reflected by the electrically controlled liquid crystal polarizer 18.

In another embodiment, it is assumed that the optical axis RPP of the reflective polarizer 184 is still horizontal, but the light ray L1 emitted from the display device 12 is S-polarized light. When electrically controlled liquid crystal polarizer 18 is not energized, liquid crystal molecules in liquid crystal cell 1826 do not rotate, and after light ray L1 enters liquid crystal cell 1826 from incident surface 1824, the polarization direction LS of light ray L1 is not changed, so that the polarization direction LS of light ray L1 exiting from exit surface 1824 is perpendicular to optical axis RPP of reflective polarizer 184, which causes reflective polarizer 184 to reflect light ray L1 exiting from exit surface 1824. In other words, when the electrically controlled liquid crystal polarizer 18 is not energized, the polarization direction LS of the light beam L1 exiting the exit surface 1824 is perpendicular to the optical axis RPP of the reflective polarizer 184, and therefore the light beam L1 exiting the display device 12 is reflected by the electrically controlled liquid crystal polarizer 18. When the electrically controlled liquid crystal polarizer 18 is energized, the liquid crystal molecules in the liquid crystal cell 1826 are rotated, and after the light ray L1 enters the liquid crystal cell 1826 from the incident surface 1824, the light ray L1 is changed from S-polarized light to P-polarized light, so that the polarization direction LP of the light ray L1 exiting from the exit surface 1824 is parallel to the optical axis RPP of the reflective polarizer 184, and the light ray L1 exiting from the exit surface 1824 passes through the reflective polarizer 184. In other words, when electrically controlled liquid crystal polarizer 18 is energized, light L1 exiting display device 12 is able to pass through electrically controlled liquid crystal polarizer 18 because the polarization direction LP of light L1 exiting exit surface 1824 is parallel to the optical axis RPP of reflective polarizer 184.

As described in the above two embodiments, the light path of the light L1 can be changed by the non-energized state and the energized state of the electrically controlled liquid crystal polarizer 18, and the present invention can project the image provided by the display device 12 at different positions. The two embodiments are for explaining why the path of the light ray L1 can be changed when the electrically controlled liquid crystal polarizer 18 is not energized and is energized, and the invention is not limited to the two embodiments, for example, in other embodiments, the optical axis RPP of the reflective polarizer 184 may be vertical.

Next, how the augmented reality head-up display 10 of fig. 1 forms two virtual images a and B is described. Referring to fig. 1 to 5, in a first time period T1, the display device 12 outputs an image a', and a light L1 emitted from the display device 12 is reflected by the mirror 16 to the electrically controlled liquid crystal polarizer 18. Assume that the light ray L1 exiting the display device 12 is P-polarized, the optical axis RPP of the reflective polarizer 184 is horizontal, and the electrically controlled liquid crystal polarizer 18 is energized at time T1. As shown in FIG. 4, by applying voltages to liquid crystal cell 1826 via an external control voltage module (not shown), liquid crystal molecules in liquid crystal cell 1826 are rotated to a predetermined alignment direction, such as polarization direction LS, and polarization direction LP of light ray L1 entering from incident surface 1822 of polarization rotator 182 is changed into polarization direction LS by liquid crystal cell 1826. Since the polarization direction LS is perpendicular to the optical axis RPP of the reflective polarizer 184, the light ray L1 exiting from the exit surface 1824 is reflected by the reflective polarizer 184 to the windshield 22. Finally, the light L1 is reflected by the windshield 22 to the human eyes 20, so that the user can see the first virtual image a at a first position in front of the windshield 22. Briefly, during the first time period T1, the optical path mirror assembly 14 switches the electrically controlled liquid crystal polarizer 18 to the energized state to switch the optical path of the light L1 to a first sub-optical path, which sequentially passes through the reflector 16, the electrically controlled liquid crystal polarizer 18 and the windshield 22 from the display device 12 to the human eye 20. The first virtual image a is located far in front of the windshield 22, so the first virtual image a can be, but is not limited to, navigation path information.

During a second time period T2 of FIG. 5, the display device 12 outputs an image B', at which time the light L1 emitted by the display device 12 is also reflected by the mirror 16 toward the electrically controlled liquid crystal polarizer 18. Since the electrically controlled liquid crystal polarizer 18 is not energized at time T2, the liquid crystal molecules in the liquid crystal cell 1826 are not rotated, as shown in fig. 3. The polarization direction LP of the light ray L1 entering from the incident surface 1822 of the polarization rotator 182 is not changed. Since the polarization direction LP is parallel to the optical axis RPP of the reflective polarizer 184, the light ray L1 exiting from the exit surface 1824 will pass through the reflective polarizer 184 and be projected to the human eye 20, so that the user can see the second virtual image B at a second location in front of the windshield 22. Briefly, during the second time interval T2, the optical lens assembly 14 switches the electrically-controlled liquid crystal polarizer 18 to the non-energized state to switch the optical path of the light L1 to a second sub-optical path, which sequentially passes through the mirror 16 and the electrically-controlled liquid crystal polarizer 18 from the display device 12 to the human eye 20. The first position is further from the second position, i.e., the first position is a greater distance from the windshield 22 than the second position is from the windshield 22. The second virtual image B is located at a position closer to the front of the windshield 22, so the second virtual image B can be, but is not limited to, vehicle speed information.

When a human eye views an object, the image of the object is imaged on the retina and is input into the human brain through the optic nerve, and then people can feel the image of the object. When the object is removed, the impression of the optic nerve on the object does not immediately disappear, and the human eye can still keep the image for about 0.1-0.4 seconds, which is called persistence of vision. The present invention utilizes the feature of persistence of vision to make the human eyes see the first virtual image a and the second virtual image B at the same time, thereby achieving the purpose that one display device 12 displays a plurality of images at the same time. Therefore, the display device 12 in fig. 1 repeatedly outputs the images a 'and B', and the time interval between the two images a '(i.e., the second time interval T2) and the time interval between the two images B' (i.e., the first time interval T1) are both less than or equal to 0.1 second. In other words, the frame rates of the images a 'and B' (or the frame rates of the first virtual image a and the second virtual image B) are greater than or equal to 10 fps.

Fig. 6 shows a second embodiment of an augmented reality head-up display according to the present invention. In fig. 6, the augmented reality head-up display 30 includes a display device 32 and an optical lens assembly 34. The display device 32 is configured to emit a light L1 to the optical path assembly 34 to form a first virtual image a or a second virtual image B in front of the windshield 22, where the light L1 may be an image, and the light L1 is S-polarized light or P-polarized light. In general, the polarization direction LS of S-polarized light is the vertical direction, and the polarization direction LP of P-polarized light is the horizontal direction. The display device 32 may be, but is not limited to, a display or a projection device. The optical path mirror assembly 34 is disposed on a light path of the light L1, and the optical path mirror assembly 34 can change the light path to project the light L1 to different positions, so as to form a first virtual image a at a first position in front of the windshield 22 or a second virtual image B at a second position in front of the windshield 22. The optical lens assembly 34 includes an electrically controlled liquid crystal polarizer 36 and a reflector 38. Electrically controllable liquid crystal polarizer 36 and mirror 38 are both disposed in the light path, and electrically controllable liquid crystal polarizer 36 is positioned between mirror 38 and display device 32. Light L1 from display device 32 may pass through or be reflected by electrically controllable liquid crystal polarizer 36, and mirror 38 reflects light L1 from electrically controllable liquid crystal polarizer 36. The electrically controlled liquid crystal polarizer 36 includes a polarization rotator 362 and a reflective polarizer 364, wherein the reflective polarizer 364 is attached to the exit surface of the polarization rotator 362. The structure and operation principle of the electrically controlled liquid crystal polarizer 36 can refer to fig. 2, fig. 3 and fig. 4, which are not described herein again.

Referring to fig. 3 and 6, in the first period T1, the display device 32 outputs an image a'. Assume that the light ray L1 exiting the display device 32 is P-polarized, the optical axis RPP of the reflective polarizer 364 is horizontal, and the electronically controlled liquid crystal polarizer 36 is energized at time T1. As shown in fig. 4, when the polarization rotator 362 is powered on, the liquid crystal molecules of the liquid crystal cell of the polarization rotator 362 are rotated, so that the polarization direction LP of the light L1 entering from the incident surface (e.g., the incident surface 1822 of fig. 4) of the polarization rotator 362 is changed into the polarization direction LS. Since the polarization direction LS is perpendicular to the optical axis RPP of the reflective polarizer 364, the light ray L1 exiting from the exit surface (e.g., exit surface 1824 of fig. 4) of the polarization rotator 362 is reflected by the reflective polarizer 364 toward the mirror 38. The mirror 38 then reflects the light L1 from the lc polarizer 36 to the windshield 22. Finally, the light L1 is reflected by the windshield 22 to the human eyes 20, so that the user can see the first virtual image a at a first position in front of the windshield 22. In brief, during the first time period T1, the optical path mirror assembly 34 switches the electrically controlled liquid crystal polarizer 36 to the energized state to switch the optical path of the light L1 to a first sub-optical path, which reaches the human eyes 20 after passing through the electrically controlled liquid crystal polarizer 36, the reflector 38 and the windshield 22 in sequence from the display device 32. The first virtual image a is located farther in front of the windshield 22, and thus may be, but is not limited to, navigation path information.

During a second time period T2, the display device 32 outputs an image B' and the electrically controlled liquid crystal polarizer 36 is not energized. Since the polarization rotator 362 of the electrically controlled liquid crystal polarizer 36 is not energized, the liquid crystal molecules of the liquid crystal cells of the polarization rotator 362 are not rotated. The polarization direction LP of the light ray L1 entering from the incident plane of the polarization rotator 362 (e.g., the incident plane 1822 of fig. 3) is not changed. Polarization direction LP is parallel to optical axis RPP of reflective polarizer 184, and thus light ray L1 exiting an exit surface (e.g., exit surface 1824 of fig. 3) will pass through reflective polarizer 364 and be projected toward windshield 22. Finally, the windscreen 22 reflects the light L1 to the eyes 20, so that the user can see the second virtual image B in a second position in front of the windscreen 22. In brief, during the second time period T2, the optical lens assembly 34 switches the electrically controlled liquid crystal polarizer 36 to the non-energized state to switch the optical path of the light L1 to a second sub-optical path, which sequentially passes through the electrically controlled liquid crystal polarizer 36 and the windshield 22 from the display device 32 to the human eyes 20. The first position is further from the second position, i.e., the first position is a greater distance from the windshield 22 than the second position is from the windshield 22. The second virtual image B is located at a position closer to the front of the windshield 22, and thus the second virtual image B may be, but is not limited to, vehicle speed information.

The display device 32 in fig. 6 repeatedly outputs the images a 'and B', and the time interval between the two images a '(i.e., the second time interval T2) and the time interval between the two images B' (i.e., the first time interval T1) are less than or equal to 0.1 second. In other words, the frame rates of the images a 'and B' (or the frame rates of the first virtual image a and the second virtual image B) are greater than or equal to 10 fps. According to the persistence of vision, the augmented reality head-up display 30 of fig. 6 allows the user to see the first virtual image a and the second virtual image B simultaneously, so that one display device 32 can display a plurality of images simultaneously.

Fig. 7 shows a third embodiment of an augmented reality head-up display according to the present invention. In fig. 7, the augmented reality head-up display 40 includes a display device 42 and an optical lens assembly 44. The display device 42 emits a light L1 to the optical path assembly 44 to form a first virtual image a, a second virtual image B, or a third virtual image C in front of the windshield 22, where the light L1 may be an image, and the light L1 is S-polarized light or P-polarized light. In general, the polarization direction LS of S-polarized light is the vertical direction, and the polarization direction LP of P-polarized light is the horizontal direction. The display device 42 may be, but is not limited to, a display or a projection device. The optical path mirror group 44 is disposed on the optical path of the light L1, and the optical path mirror group 44 can change the optical path. To project light line L1 to different locations to form a first virtual image a at a first location in front of windshield 22, a second virtual image B at a second location in front of windshield 22, or a third virtual image C at a third location in front of windshield 22. The optical lens assembly 44 includes a first electrically controllable liquid crystal polarizer 46 and a second electrically controllable liquid crystal polarizer 48. A first electrically controlled liquid crystal polarizer 46 and a second electrically controlled liquid crystal polarizer 48 are disposed in the light path, with the second electrically controlled liquid crystal polarizer 48 being positioned between the first electrically controlled liquid crystal polarizer 46 and the display device 42. Light ray L1 from display device 42 may pass through electrically controlled liquid crystal polarizer 46 or be reflected by electrically controlled liquid crystal polarizer 46. Light ray L1 from electrically controllable liquid crystal polarizer 46 may pass through electrically controllable liquid crystal polarizer 48 or be reflected by electrically controllable liquid crystal polarizer 48. The first electrically controlled liquid crystal polarizer 46 includes a polarization rotator 462 and a reflective polarizer 464, wherein the reflective polarizer 464 is attached to the exit surface of the polarization rotator 462. The second electrically controlled liquid crystal polarizer 48 includes a polarization rotator 482 and a reflective polarizer 484, the reflective polarizer 484 attached to the exit surface of the polarization rotator 482. The structure and operation principle of the first electrically controlled liquid crystal polarizer 46 and the second electrically controlled liquid crystal polarizer 48 can be referred to fig. 2, fig. 3 and fig. 4, which are not described herein again.

FIG. 8 shows an embodiment of the display device 42 of FIG. 7 outputting three different images, and the display device 12 sequentially outputs an image A ', an image B ' and an image C '. Referring to fig. 7 and 8, in the first period T1, the display device 42 outputs an image a'. Assume that the light ray L1 emitted by the display device 42 is P-polarized and that the first electrically controlled liquid crystal polarizer 46 and the second electrically controlled liquid crystal polarizer 48 are energized at time T1. As shown in fig. 4, when the polarization rotator 462 of the first electrically controlled liquid crystal polarizer 46 is energized, the liquid crystal molecules of the liquid crystal cells of the polarization rotator 462 are rotated, and thus the polarization direction LP of the light ray L1 entering from the incident plane of the polarization rotator 462 (e.g., the incident plane 1822 of fig. 4) is changed to the polarization direction LS. Since the polarization direction LS is perpendicular to the optical axis RPP of the reflective polarizer 464, a light ray L1 exiting from the exit surface (e.g., exit surface 1824 of fig. 4) of the polarization rotator 462 is reflected by the reflective polarizer 464 to the second electrically controllable liquid crystal polarizer 48. Since the polarization rotator 482 of the second electrically controlled liquid crystal polarizer 48 is also energized, the liquid crystal molecules of the liquid crystal cell of the polarization rotator 482 are rotated, and the polarization direction LP of the light ray L1 entering from the incident surface (e.g., the incident surface 1822 of fig. 4) of the polarization rotator 482 will be changed into the polarization direction LS. Since the polarization direction LS is perpendicular to the optical axis RPP of the reflective polarizer 484, a light ray L1 exiting from the exit surface (e.g., exit surface 1824 of fig. 4) of the polarization rotator 482 is reflected by the reflective polarizer 484 toward the windshield 22. Finally, the light L1 is reflected by the windshield 22 to the human eyes 20, so that the user can see the first virtual image a at a first position in front of the windshield 22. In brief, during the first time interval T1, the optical lens assembly 44 switches the first electrically controlled liquid crystal polarizer 46 and the second electrically controlled liquid crystal polarizer 48 to the energized state to switch the optical path of the light L1 to a first sub-optical path, which reaches the human eyes 20 from the display device 42 through the first electrically controlled liquid crystal polarizer 46, the second electrically controlled liquid crystal polarizer 48 and the windshield 22 in sequence.

In the second time period T2, the display device 42 outputs the video B'. It is assumed that during the second time period T2, the first electrically controlled liquid crystal polarizer 46 is energized and the second electrically controlled liquid crystal polarizer 48 is not energized. As previously described, the energized first electrically controlled liquid crystal polarizer 46 will reflect the light ray L1 from the display device 42 to the second electrically controlled liquid crystal polarizer 48. Since the polarization rotator 482 of the second electrically controllable liquid crystal polarizer 48 is not energized, the polarization direction LP of light ray L1 entering from the plane of incidence of the polarization rotator 482 (e.g., plane of incidence 1822 of FIG. 3) is not altered. The polarization direction LP is parallel to the optical axis RPP of the reflective polarizer 484, so that a light ray L1 exiting from the exit surface (e.g., exit surface 1824 of fig. 3) of the polarization rotator 482 will pass through the reflective polarizer 484 and be projected to the human eye 20, and the user can see a second virtual image B at a second location in front of the windshield 22. In brief, during the second time interval T2, the optical lens assembly 44 switches the first electrically controlled liquid crystal polarizer 46 to the energized state and switches the second electrically controlled liquid crystal polarizer 48 to the de-energized state to switch the optical path of the light L1 to a second sub-optical path, which sequentially passes through the first electrically controlled liquid crystal polarizer 46 and the second electrically controlled liquid crystal polarizer 48 from the display device 42 to the human eye 20.

In the third time period T3, the display device 42 outputs the image C'. Assume that during the third time period T3, neither the first electrically controlled liquid crystal polarizer 46 nor the second electrically controlled liquid crystal polarizer 48 is energized. Since the polarization rotator 462 of the first electrically controllable liquid crystal polarizer 46 is not energized, the polarization direction LP of light ray L1 entering from the plane of incidence of the polarization rotator 462 (e.g., plane of incidence 1822 of FIG. 3) is not altered. The polarization direction LP is parallel to the optical axis RPP of the reflective polarizer 464, and thus a light ray L1 exiting an exit surface (e.g., exit surface 1824 of fig. 3) of the polarization rotator 462 will pass through the reflective polarizer 464 and be projected onto the windshield 22. Finally, the windshield 22 reflects the light L1 to the human eyes 20, so that the user can see the third virtual image C at a third position in front of the windshield 22. In brief, during the third time interval T3, the optical lens assembly 44 switches the first electrically controlled liquid crystal polarizer 46 and the second electrically controlled liquid crystal polarizer 48 to the non-energized state to switch the optical path of the light L1 to a third sub-optical path, which sequentially passes through the first electrically controlled liquid crystal polarizer 46 and the windshield 22 from the display device 42 to the human eyes 20. The first position is further than the third position, and the third position is further than the second position. In other words, the first position is a greater distance from the windshield 22 than the third position is from the windshield 22, and the third position is a greater distance from the windshield 22 than the second position is from the windshield 22.

The display device 42 in fig. 7 repeatedly outputs the image a ', the image B' and the image C ', and the time interval between two images a' (i.e., T2+ T3), two images B '(i.e., T1+ T3) and two images C' (i.e., T1+ T2) are less than or equal to 0.1 second. In other words, the frame rates of the image a ', the image B ', and the image C ' (or the frame rates of the first virtual image a, the second virtual image B, and the third virtual image C) are greater than or equal to 10 fps. According to the persistence of vision characteristic, the augmented reality head-up display 40 of fig. 7 allows the user to see the first virtual image a, the second virtual image B, and the third virtual image C simultaneously, so that one display device 42 can display a plurality of images simultaneously.

Although the present invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An augmented reality heads-up display, comprising:

a display device for emitting light; and

the light path lens group is arranged on the light path of the light rays, and comprises an electric control liquid crystal polaroid arranged on the light path:

wherein, during a first time interval, the electrically controlled liquid crystal polarizer reflects the light rays to form a first virtual image at a first position;

wherein, during a second time interval, the light ray penetrates through the electrically controlled liquid crystal polarizer to form a second virtual image at a second position;

the electrically controlled liquid crystal polarizer includes:

a polarization rotator having an incident surface and an exit surface, wherein the polarization rotator changes a polarization direction of the light entering from the incident surface when the polarization rotator is energized; and

a reflective polarizer disposed on the exit surface, the reflective polarizer having an optical axis, wherein the light ray emitted from the exit surface passes through the reflective polarizer when the polarization direction of the light ray emitted from the exit surface is parallel to the optical axis, and the reflective polarizer reflects the light ray emitted from the exit surface when the polarization direction of the light ray emitted from the exit surface is perpendicular to the optical axis.

2. The augmented reality head-up display of claim 1, wherein the optical path mirror further comprises a mirror disposed in the optical path between the electrically controlled liquid crystal polarizer and the display device, the mirror configured to reflect the light from the display device to the electrically controlled liquid crystal polarizer.

3. The augmented reality head-up display of claim 1, wherein the optical path mirror further comprises a mirror disposed in the optical path and the electrically controlled liquid crystal polarizer is between the mirror and the display device, wherein during the first time period, the mirror reflects the light from the electrically controlled liquid crystal polarizer to form the first virtual image at the first position.

4. The augmented reality heads-up display of claim 1 wherein the display device is a display or a projection device.

5. The augmented reality head-up display of claim 1, wherein the light emitted by the display device is S-polarized light or P-polarized light.

6. The augmented reality heads-up display of claim 1 wherein the frame rate of the first and second virtual images is greater than or equal to 0.1 seconds.

7. The augmented reality heads-up display of claim 1 wherein the first position is further from the second position.

8. The augmented reality head-up display of claim 1, wherein the light path comprises a first sub light path and a second sub light path, the optical path mirror switching the electrically controlled liquid crystal polarizer between an energized state and an unenergized state to switch the light path to the first sub light path to form the first virtual image during the first period and to switch the light path to the second sub light path to form the second virtual image during the second period.

9. An augmented reality heads-up display, comprising:

a display device for emitting light; and

the light path mirror group is arranged on the light path of the light and comprises:

a first electrically controlled liquid crystal polarizer disposed on the optical path; and

a second electrically controlled liquid crystal polarizer disposed on the light path and between the first electrically controlled liquid crystal polarizer and the display device;

wherein, during a first time period, the first electrically controlled liquid crystal polarizer reflects the light rays from the display device and the second electrically controlled liquid crystal polarizer reflects the light rays from the first electrically controlled liquid crystal polarizer to form a first virtual image at a first location;

wherein, during a second time period, the first electrically controlled liquid crystal polarizer reflects the light rays from the display device, and the light rays from the first electrically controlled liquid crystal polarizer penetrate the second electrically controlled liquid crystal polarizer to form a second virtual image at a second location;

wherein, during a third time period, the light rays from the display device penetrate through the first electrically controlled liquid crystal polarizer to form a third virtual image at a third location.

10. The augmented reality heads-up display of claim 9 wherein the first electronically controlled liquid crystal polarizer comprises:

a polarization rotator having an incident surface to which the light from the display device is incident and an exit surface, and changing a polarization direction of the light entering from the incident surface when the polarization rotator is energized; and

11. The augmented reality heads-up display of claim 9 wherein the second electronically controlled liquid crystal polarizer comprises:

a polarization rotator having an entrance face and an exit face, wherein said light from said first electrically controlled liquid crystal polarizer is incident on said entrance face, and said polarization rotator changes the polarization direction of said light entering from said entrance face when said polarization rotator is energized; and

12. The augmented reality heads-up display of claim 9 wherein the display device is a display or a projection device.

13. The augmented reality head-up display of claim 9, wherein the light emitted by the display device is S-polarized light or P-polarized light.

14. The augmented reality heads-up display of claim 9 wherein the frame rates of the first, second and third virtual images are greater than or equal to 0.1 seconds.

15. The augmented reality heads-up display of claim 9 wherein the first position is further from the third position and the third position is further from the second position.

16. The augmented reality heads-up display of claim 9 wherein the light path includes a first sub light path, a second sub light path and a third sub light path, the optical path mirror switching the powered state and the unpowered state of the first electrically controlled liquid crystal polarizer and the second electrically controlled liquid crystal polarizer to switch the light path to the first sub light path to form the first virtual image during the first time period, to switch the light path to the second sub light path to form the second virtual image during the second time period, and to switch the light path to the third sub light path to form the third virtual image during the third time period.