CN114815236A - Symmetrical light path 3D head-up display - Google Patents
Symmetrical light path 3D head-up display Download PDFInfo
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- CN114815236A CN114815236A CN202110110432.8A CN202110110432A CN114815236A CN 114815236 A CN114815236 A CN 114815236A CN 202110110432 A CN202110110432 A CN 202110110432A CN 114815236 A CN114815236 A CN 114815236A
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/0101—Head-up displays characterised by optical features
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
- G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
- G02B30/22—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the stereoscopic type
- G02B30/24—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the stereoscopic type involving temporal multiplexing, e.g. using sequentially activated left and right shutters
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
- G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
- G02B30/22—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the stereoscopic type
- G02B30/25—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the stereoscopic type using polarisation techniques
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
- G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
- G02B30/34—Stereoscopes providing a stereoscopic pair of separated images corresponding to parallactically displaced views of the same object, e.g. 3D slide viewers
- G02B30/35—Stereoscopes providing a stereoscopic pair of separated images corresponding to parallactically displaced views of the same object, e.g. 3D slide viewers using reflective optical elements in the optical path between the images and the observer
Abstract
A symmetrical light path 3D head-up display comprises a projection module, a first light source and a second light source, wherein the projection module alternately projects first image light and second image light in a time-sharing manner; the light splitter is positioned on the light path of the projection module, reflects the first image light and allows the second image light to penetrate through; and the reflecting mirror module is two reflecting mirrors, is arranged symmetrically to the light splitter and is positioned at two opposite sides of the light splitter, respectively reflects the first image light and the second image light, and projects the first image light and the second image light to a reflecting type diffusion sheet, and the reflecting type diffusion sheet reflects the first image light and the second image light to the receiving range of the first eye and the second eye. Through the arrangement, the light paths from the first image light and the second image light to the reflective diffusion sheet after light splitting are symmetrically arranged, so that the lengths of the first eye image light path and the second eye image light path are still maintained to be the same when the virtual image projection distance is longer or the magnification ratio is higher, clear images are displayed on the reflective diffusion sheet, and clear binocular stereoscopic images are projected.
Description
Technical Field
The invention relates to a symmetrical light path 3D head-up display, which can still maintain the same length of left and right eye image light paths when a virtual image projection distance is longer or the magnification ratio is higher, and clear images are displayed on a reflective diffusion sheet so as to project clear binocular stereoscopic images.
Background
In the light path of the vehicular head-up display, a concave mirror 61 is usually used to enlarge the image on the display screen, as shown in fig. 1A; particularly, when applied to a stereoscopic and augmented reality head-up display (AR-HUD), in order to be more conformable to a real scene and reduce the convergence accommodation conflict, a longer Virtual Image Distance (VID) of at least 7.5 m to 20 m is required, and thus a concave mirror 62 having a higher magnification is required, as shown in fig. 1B.
As shown in fig. 2, in the prior patent, a single projection module 1 is used, the parallax image light of left eye viewing angle and the parallax image light of right eye viewing angle are projected in a time-sharing manner through the lens of the projection module, the two image lights are time-shared and modulated into the parallax polarized image light of left eye and the parallax polarized image light of right eye with the polarization directions perpendicular to each other through the polarization modulator 2, the two image lights are reflected and transmitted through the beam splitter (reflective polarizer 3) to be separated, the reflected image light is projected on the reflective diffusion sheet 5, the transmitted image light penetrates the beam splitter (reflective polarizer 3) again after being reflected by the reflector 40 behind the beam splitter (reflective polarizer 3), and then projected onto a reflective diffusion sheet 5, which reflects and diffuses the left and right eye parallax polarized image light to a concave mirror 6, thereby enlarging the image to be displayed and increasing the distance of the virtual image.
As shown in fig. 3, the left and right eye parallax polarized image light is finally reflected to the left eye E1 and the right eye E2 of the viewer through the windshield 7, and the left and right eyes see the images at different parallax angles, respectively, thereby forming a stereoscopic image in the brain.
As shown in fig. 4A, the beam splitter (reflective polarizer 3) and the reflector 40 are both used to fold the light path, so the equivalent projection structure can be regarded as two left and right projection modules 100, as shown in fig. 4B, and the projection central axes 101 of the two projectors 100 form an included angle a and project toward the reflective diffusion sheet 5.
As shown in fig. 5A, this method is suitable for a condition where a small projection angle difference, that is, an included angle between the projection central axes 101 of the left and right equivalent projectors on the reflective diffusion sheet 5 is small, for example, the included angle a1 is 5 degrees. The image light is emitted from the projector to the reflective diffusion sheet 5, the reflective diffusion sheet 5 reflects and diffuses the image light to the concave mirror 61, and the concave mirror 61 reflects the image light to the left eye E1 or the right eye E2 of the viewer, as shown in fig. 5B. However, in an application requiring a longer Virtual Image Distance (VID), it is necessary to use a concave mirror 62 having a higher magnification, that is, a smaller curvature radius, and in this case, if the difference in angles projected by the left and right equivalent projectors onto the reflective diffusion sheet 5 is maintained, the concave mirror 62 cannot reflect the image light to the left eye E1 or the right eye E2 of the viewer, as shown in fig. 5C.
As shown in fig. 6A, in order for the concave mirror 62 to reflect and collect the image light to the eyes of the viewer for the application of the longer Virtual Image Distance (VID), the difference between the angles projected by the left and right equivalent projectors onto the reflective diffusion sheet 5 must be increased, for example, the included angle a2 is 10 degrees. As shown in fig. 6B, at this time, the image light is projected onto the reflective diffusion sheet 5 by the two left and right projectors having a large projection angle difference, the reflective diffusion sheet 5 reflects and diffuses the image light toward the concave mirror 62 having a large magnification, and the concave mirror 62 reflects the image light toward the left eye E1 or the right eye E2 of the viewer.
As shown in fig. 7, in a projector, such as a DLP or LCD projector, the imaging lens 10 has a focal length characteristic, and after passing through the lens 10, the image light L0 must be projected onto a cloth curtain or a reflective diffusion sheet 5 located at the focal length to form a clear image.
As shown in fig. 8A, in the prior art, the image light projected by the imaging lens 10 of the projector is divided into two different light paths by the beam splitter (reflective polarizer 3) and projected onto the reflective diffusion sheet 5, the two light paths have different lengths, and only one light path length is equal to the focal length of the imaging lens 10. When the difference between the angles projected by the left and right equivalent projectors onto the reflective diffusion sheet 5 is not large, for example, the included angle is 5 degrees, the optical path difference is also not large. As shown in fig. 8B, if the optical path length of the polarized image light L11 is equal to the focal length of the imaging lens 10, the polarized image light L11 can form a clear image on the reflective diffusion sheet 5; as shown in fig. 8C, at this time, the optical path length of the polarized image light L12 is slightly shorter than the focal length of the imaging lens 10, and the polarized image light L12 is focused a little behind the reflective diffusion sheet 5, so that the image is slightly blurred. If the optical path length of the polarized image light L12 is equal to the focal length of the imaging lens 10, the polarized image light L12 can form a sharp image on the reflective diffusion sheet 5, and the polarized image light L11 will be focused a little behind the diffusion sheet, so that the image is slightly blurred.
As shown in fig. 9A, when the angle difference of the light to be projected to the reflective diffusion sheet 5 is large, for example, 10 degrees or more, the optical path length of the two-time transmission beam splitter (reflective polarizer 3) is significantly longer than the optical path length of the light reflected by the beam splitter (reflective polarizer 3), and the optical path difference between the two optical paths is relatively large. As shown in fig. 9B, if the optical path length of the polarized image light L11 is equal to the focal length of the imaging lens 10, the polarized image light L11 can form a clear image on the reflective diffusion sheet 5; as shown in fig. 9C, at this time, the optical path length of the polarized image light L12 is shorter than the focal length of the imaging lens 10, and the polarized image light L12 is focused at a position far behind the reflective diffusion sheet, so that a clear image cannot be formed on the reflective diffusion sheet 5, and the image blur is difficult to be recognized. If the optical path length of the polarized image light L12 is equal to the focal length of the imaging lens 10, the polarized image light L12 can form a clear image on the reflective diffusion sheet 5, and the polarized image light L11 is focused at a position far behind the diffusion sheet, so that a clear image cannot be formed on the reflective diffusion sheet 5, and the image blur is difficult to be recognized.
In many patents, for example, JPH10186522A, TW578011, TW396280, CN108919495, TW200916828, TW201019031, TW201214014, TW I349114, TW I359284, TW342101, TW M478830, TWI626475, and TWM434219, display optical path arrangements for generating stereoscopic images are disclosed.
Disclosure of Invention
The invention provides a symmetrical light path 3D head-up display, comprising:
the projection module is provided with an imaging lens and alternately projects a first image light and a second image light in a time-sharing manner;
a polarization modulator for modulating the first image light into a first polarized image light and modulating the second image light into a second polarized image light, the polarization directions of the first polarized image light and the second polarized image light being perpendicular to each other;
a polarizing beam splitter having a light splitting surface for reflecting the first polarized image light and allowing the second polarized image light to pass therethrough;
a reflector module, which is a two-sided reflector symmetrically arranged on the light splitting surface and respectively reflects the first polarized image light and the second polarized image light;
the light path between the first polarized image light and the second polarized image light after being split by the polarizing beam splitter and the reflective diffusion sheet is symmetrically arranged, the angles of incidence of the first polarized image light and the second polarized image light to the reflective diffusion sheet are different, the micro curved mirrors reflect and diffuse the first polarized image light to a first eye receiving range, and the micro curved mirrors reflect and diffuse the second polarized image light to a second eye receiving range.
The reflective diffusion sheet reflects and diffuses the first polarized image light and the second polarized image light to the concave mirror, the concave mirror reflects the first polarized image light and the second polarized image light to the windshield, and the windshield reflects the first polarized image light and the second polarized image light to the first eye receiving range and the second eye receiving range respectively.
The projector further comprises a shutter set arranged between the reflector module and the polarizing beam splitter, wherein shutters are respectively arranged in front of the two symmetrically arranged reflectors, the two shutters are opened and closed at opposite time sequences, and the time sequences and the projection module alternately project the first image light and the second image light in a time-sharing mode.
Wherein the polarizing beam splitter is a reflective polarizer.
Wherein the polarizing beam splitter is a polarizing beam splitter.
The invention also provides a symmetrical light path 3D head-up display, comprising:
the projection module is provided with an imaging lens and alternately projects a first image light and a second image light in a time-sharing manner;
a semi-reflective beam splitter, which is a semi-reflective mirror having a semi-reflective surface, partially reflecting the first image light and the second image light, and allowing the first image light and the second image light to partially penetrate;
a reflector module, which is a two-sided reflector symmetrically arranged on the semi-reflecting surface and respectively reflects the first image light and the second image light;
a shutter set arranged between the reflector module and the semi-reflecting mirror, wherein shutters are respectively arranged in front of two symmetrically arranged reflectors, the two shutters are opened and closed at opposite time sequences, the time sequences and the projection module alternately project the first image light and the second image light synchronously in a time-sharing manner, one shutter is opened when one image light is projected, the image light is emitted to one reflector, and the other shutter is closed, so that the image light is blocked and absorbed and cannot reach the other reflector;
the reflective diffusion sheet is provided with a plurality of micro-curved mirrors which are arranged in an array mode, light paths between first image light and second image light after the first image light and the second image light are split by the semi-reflective light splitter and the reflective diffusion sheet are symmetrically arranged, the first image light is reflected and diffused to a first eye receiving range by the micro-curved mirrors due to different incidence angles of the first image light and the second image light to the reflective diffusion sheet, and the second image light is reflected and diffused to a second eye receiving range by the micro-curved mirrors.
The concave mirror is arranged between the reflective diffusion sheet and the windshield, the reflective diffusion sheet reflects the first image light and the second image light to the concave mirror, the concave mirror reflects the first image light and the second image light to the windshield, and the windshield reflects the first image light and the second image light to the first eye receiving range and the second eye receiving range respectively.
The invention further provides a symmetrical light path 3D head-up display, comprising:
the projection module is provided with an imaging lens and alternately projects a first image light and a second image light in a time-sharing manner;
a reflection rotary light splitter, which is a rotary shutter and has a rotary light splitting surface to define a reflection region and a transmission region, wherein the reflection region and the transmission region are alternately positioned at the projection position of the projection module, so that the reflection region reflects the first image light or the second image light penetrates the transmission region;
a reflector module, which is a two-sided reflector symmetrically arranged on the rotating light splitting surface and respectively reflects the first image light and the second image light;
the reflective diffusion sheet is provided with a plurality of micro-curved mirrors which are arranged in an array mode, light paths between first image light and second image light which are split by a reflective rotary light splitter and then reach the reflective diffusion sheet are symmetrically arranged, the first image light is reflected and diffused to a first eye receiving range by the micro-curved mirrors due to the fact that angles of incidence of the first image light and the second image light to the reflective diffusion sheet are different, and the second image light is reflected and diffused to a second eye receiving range by the micro-curved mirrors.
The concave mirror is arranged between the reflective diffusion sheet and the windshield, the reflective diffusion sheet reflects the first image light and the second image light to the concave mirror, the concave mirror reflects the first image light and the second image light to the windshield, and the windshield reflects the first image light and the second image light to the first eye receiving range and the second eye receiving range respectively.
The rotary shutter is in a disc shape and rotates by using the central point of the disc, the rotation speed of the disc and the time sequence of the projection module alternately project the first image light and the second image light in a time-sharing mode are synchronous, the projection module projects the first image light, the disc rotates to the reflection area, the first image light is reflected by the reflection area, the projection module projects the second image light, the disc rotates to the transmission area, and the second image light penetrates through the transmission area.
Drawings
Fig. 1A and 1B are schematic views of a conventional head-up display for a vehicle.
Fig. 2 is a schematic diagram of a conventional projection apparatus for projecting a stereoscopic image.
Fig. 3 is a schematic diagram of a conventional vehicle head-up display for projecting stereoscopic images.
Fig. 4A and 4B are schematic equivalent optical path diagrams of a conventional projection apparatus for projecting stereoscopic images.
Fig. 5A, 5B, and 5C are schematic diagrams of projection angle differences of a conventional projection apparatus for projecting stereoscopic images.
Fig. 6A and 6B are another schematic views of the projection angle difference of the conventional projection apparatus for projecting stereoscopic images.
Fig. 7 is a focusing schematic diagram of a conventional projector imaging lens.
Fig. 8A, 8B, and 8C are schematic diagrams illustrating small projection angle differences of a conventional projection apparatus for projecting stereoscopic images. Fig. 8B is a diagram illustrating the optical path of a light ray (twice) passing through the beam splitter, and fig. 8C is a diagram illustrating the optical path of a light ray reflected by the beam splitter.
Fig. 9A, 9B, and 9C are schematic diagrams illustrating a large projection angle difference of a conventional projection apparatus for projecting a stereoscopic image. Fig. 9B is a diagram illustrating the optical path of a light ray (twice) passing through the beam splitter, and fig. 9C is a diagram illustrating the optical path of a light ray reflected by the beam splitter.
Fig. 10A, 10B, and 10C are schematic symmetrical optical path diagrams of the first embodiment for projecting stereoscopic images.
Fig. 11A, 11B, and 11C are schematic diagrams illustrating small projection angle differences of symmetric optical paths according to the first embodiment of projecting a stereoscopic image.
Fig. 12A, 12B, and 12C are schematic diagrams illustrating a large projection angle difference of the symmetric optical paths according to the first embodiment for projecting a stereoscopic image.
Fig. 13A and 13B are schematic perspective views of a vehicle using symmetric optical path split projection according to the first embodiment for projecting a stereoscopic image.
Fig. 14A and 14B are schematic diagrams illustrating light leakage of symmetric light path splitting according to the first embodiment of projecting a stereoscopic image.
Fig. 15A, 15B, and 15C are schematic diagrams of the first embodiment of the symmetric optical path beam splitting with shutter projection for projecting stereoscopic images.
Fig. 16A and 16B are schematic perspective views of a symmetric optical path splitting with shutter projection according to a first embodiment for projecting a stereoscopic image.
Fig. 17A and 17B are schematic diagrams of a symmetric optical path light splitting with shutter projection according to a second embodiment for projecting a stereoscopic image.
Fig. 18 is a perspective view of a symmetric optical path beam splitting with shutter projection according to a second embodiment for projecting a stereoscopic image.
Fig. 19 is another perspective view of a vehicle with a symmetric optical path beam splitting and shutter projection according to the second embodiment for projecting a stereoscopic image.
Fig. 20A, 20B, and 20C are schematic symmetrical optical path splitting diagrams of a third embodiment for projecting a stereoscopic image.
Fig. 21A and 21B are schematic diagrams of symmetric optical path splitting projection of the third embodiment for projecting stereoscopic images.
Fig. 22A and 22B are another schematic diagrams of symmetric optical path splitting projection of the third embodiment for projecting a stereoscopic image.
Fig. 23 is a perspective view of a vehicle with symmetric optical path split projection of the third embodiment for projecting stereoscopic images.
Description of reference numerals: 2-a polarization modulator; 3-a reflective polarizer; 5-a reflective diffuser; 40-a mirror; 6,61, 62-concave mirrors; 7-a windshield; e1-left eye; e2-right eye; 100-a projection module; 101-a central axis; a, A1, A2-angle; 10-a lens; l0-image light; l11, L12-polarized image light; 1-a projection module; 10-an imaging lens; 2-a polarization modulator; a 3-polarizing beam splitter; 31-a light splitting surface; 4-a mirror module; 41. 42-a mirror; 5-a reflective diffuser; 6-concave mirror; 7-a windshield; 8-a shutter group; 81, 82-shutter; 85-rotary shutter; 850-rotating the light splitting surface; 851-a reflective region; 852-penetration zone; 9-a half-mirror; 91-semi-reflective surface; d1, D2-image light; e1, E2-eye; l1, L2, L10, L20-polarized image light; LP1, LP 2-light path; r1, R2-region.
Detailed Description
As shown in fig. 10A to 16B, the first embodiment of the symmetrical optical path 3D head-up display includes:
as shown in fig. 10A, a projection module 1 having an imaging lens 10 alternately projects a first image light D1 and a second image light D2 in a time-sharing manner, wherein the first image light D1 and the second image light D2 carry images with different parallax angles;
a polarization modulator 2 for modulating the first image light D1 into a first polarized image light L1 and the second image light D2 into a second polarized image light L2, wherein the polarization directions of the first polarized image light L1 and the second polarized image light L2 are perpendicular to each other;
a polarizing beam splitter 3 having a light splitting surface 31 for reflecting the first polarized image light L1 and allowing the second polarized image light L2 to pass therethrough;
a reflector module 4, which is a two- sided reflector 41, 42 symmetrically disposed on the splitting surface 31, and the two reflectors 41, 42 are located on two opposite sides of the splitting surface 31, taking the direction shown in fig. 10A as an example, the reflectors 41, 42 are respectively located above and below the splitting surface 31, the reflector 41 reflects the first polarized image light L1 reflected by the polarizing beam splitter 3, and the reflector 42 reflects the second polarized image light L2 passing through the polarizing beam splitter 3;
a reflective diffusion sheet 5 having a plurality of micro-curved mirrors arranged in an array, wherein the optical paths between the first polarized image light L1 and the second polarized image light L2 after being split by the polarizing beam splitter 3 and the reflective diffusion sheet 5 are symmetrically arranged, and since the angles of incidence of the first polarized image light L1 and the second polarized image light L2 to the reflective diffusion sheet 5 are different, as shown in fig. 10B, the micro-curved mirrors of the reflective diffusion sheet 5 reflect and diffuse the first polarized image light L1 to a first region R1, the first region R1 extends to one of the eye acceptance ranges, the micro-curved mirrors of the reflective diffusion sheet 5 reflect and diffuse the second polarized image light L2 to a second region R2, and the second region R2 extends to the other eye acceptance range; wherein the polarizing beam splitter 3 is a reflective polarizer (as shown in fig. 10A) or a polarizing beam splitter (as shown in fig. 10C).
As shown in fig. 11A, the first polarized image light L1 and the second polarized image light L2 after being split are respectively projected to two different light paths LP1 and LP2, and reflected to the reflective diffusion sheet 5 through the symmetrically arranged reflection mirrors 41 and 42, and when the angle difference between the two light paths LP1 and LP2 projected to the reflective diffusion sheet 5 is small, for example, the included angle between LP1 and LP2 is 5 degrees, and the lengths of the two light paths LP1 and LP2 are the same and symmetrical, so the light path lengths from the two polarized image lights L1 and L2 to the reflective diffusion sheet 5 are both equal to the focal length of the imaging lens 10, and there is no light path difference, and the two polarized image lights L1 and L2 can both form a clear image on the reflective diffusion sheet, as shown in fig. 11B and fig. 11C.
As shown in fig. 12A, even when the difference between the angles at which the two light paths LP1 and LP2 are projected onto the reflective diffusion sheet 5 is large, for example, the included angle between LP1 and LP2 is 10 degrees or more, the light paths are symmetrical, and thus there is no optical path difference. The optical path lengths from the two polarized image lights L1 and L2 to the reflective diffusion sheet 5 are equal to the focal length of the imaging lens 10, and the two polarized image lights L1 and L2 can both form clear images on the reflective diffusion sheet 5, as shown in fig. 12B and 12C.
As shown in fig. 13A, the display device further includes a windshield 7 and a concave mirror 6, the concave mirror 6 is disposed between the reflective diffuser 5 and the windshield 7, the reflective diffuser 5 reflects and diffuses the first polarized image light L1 and the second polarized image light L2 to the concave mirror 6, the concave mirror 6 reflects the first polarized image light L1 and the second polarized image light L2 to the windshield 7, and the windshield 7 reflects the first polarized image light L1 and the second polarized image light L2 to the first eye E1 receiving range and the second eye E2 receiving range respectively. The polarizing beam splitter 3 is a reflective polarizer or a polarizing beam splitter, the first polarized image light L1 and the second polarized image light L2 are split by the polarizing beam splitter 3 and then reflected on a reflective diffusion sheet 5 through two symmetrically arranged mirrors 41 and 42, the reflective diffusion sheet 5 reflects and diffuses the first polarized image light L1 and the second polarized image light L2 to the concave mirror 6, so as to amplify the image to be displayed and also lengthen the distance of the virtual image. The concave mirror 6 reflects the first polarized image light L1 and the second polarized image light L2 to the windshield 7, and finally the first polarized image light L1 and the second polarized image light L2 are reflected to the first eye E1 receiving range and the second eye E2 receiving range respectively through the windshield 7, as shown in fig. 13B, the left and right eyes respectively see pictures with different parallax angles, and a stereoscopic image is formed in the brain.
In an ideal implementation, the polarization beam splitter 3 reflects all the first polarized image light L1 and transmits all the second polarized image light L2 because the polarization directions of the first polarized image light L1 and the second polarized image light L2 are perpendicular to each other, and one of the polarization directions of the first polarized image light L1 is reflected by the polarization beam splitter 3 and the other polarization direction of the first polarized image light L2 is transmitted through the polarization beam splitter 3 for light splitting. However, in practice, light will be reflected and transmitted in different proportions when passing through two different media, as shown in fig. 14A, the first polarized image light L1 will be mostly reflected, and part of the transmitted light L10 will enter the optical path of the second polarized image light L2, as shown in fig. 14B, the second polarized image light L2 will be mostly transmitted, and part of the reflected light L20 will enter the optical path of the first polarized image light L1, and will not reach completely clean light split, so the left eye will see a slight right eye image, for example, a bright right eye image of 1/40, and the right eye will also see a slight left eye image, for example, a bright left eye image of 1/40.
In order to solve the problem of light leakage, as shown in fig. 15A, a shutter set 8 is further included, which is disposed between the mirror module 4 and the polarizing beam splitter 3, and shutters 81 and 82 are disposed in front of the symmetrically disposed two mirrors 41 and 42, respectively, and the two shutters 81 and 82 are opened and closed at opposite timings, and the timing and the projection module 1 alternately project the first image light D1 and the second image light D2 in a time-sharing manner, so that the incomplete light splitting mechanism of the polarizing beam splitter 3 can be solved, even if there is some light leakage, the light can be blocked by the shutters 81 and 82, and the purpose of completely and cleanly splitting light can be achieved. As shown in fig. 15B, when the first image light D1 is projected, the shutter 81 is opened, and the first polarized image light L1 that should be totally reflected by the polarizing beam splitter 3 enters the optical path of the second polarized image light L2 with a part of the penetrating light L10, but is immediately blocked and absorbed by the closed shutter 82, and cannot reach the mirror 42. As shown in fig. 15C, when the second image light D2 is projected, the shutter 82 is opened, and the second polarized image light L2 that should be transmitted by the polarizing beam splitter 3 is partially reflected light L20 into the optical path of the first polarized image light L1, but is immediately blocked and absorbed by the closed shutter 81, and cannot reach the mirror 41 (see fig. 15C).
The shutter set 8 can be an electronic shutter or a mechanical shutter; as shown in fig. 16A, the electronic shutters control, for example, opaque (closed) and transparent (open) liquid crystal shutters 81 and 82 of the liquid crystal lenses by electronic signals. As shown in fig. 16B, the mechanical shutter is, for example, a rotary shutter 83, 84 that blocks (closes) a part of the area of the disk and penetrates (opens) another part of the area to rotate at the center point. The shutters 8 with opposite timing sequences and synchronous with the projector are arranged in front of the reflectors 41 and 42 symmetrically arranged on two sides, so that even if the polarizing beam splitter 3 cannot achieve completely clean beam splitting, downward light leakage can be effectively blocked, the light leakage cannot enter another light path, the effect of about 1/1000 is achieved, namely, only the brightness of the image of the other eye of 1/1000 is seen at one eye, and the quality of stereoscopic vision is greatly improved.
As shown in fig. 17A to 19, a second embodiment of a symmetric optical path 3D head-up display includes:
a projection module 1 having an imaging lens 10 for alternately projecting a first image light D1 and a second image light D2 at different times;
a half-reflective beam splitter, which is a half-reflective mirror 9 having a half-reflective surface 91, partially reflecting the first image light D1 and the second image light D2, and allowing the first image light D1 and the second image light D2 to partially penetrate therethrough;
a mirror module 4, which is a two- sided mirror 41, 42 symmetrically disposed on the semi-reflective surface 91 and located on two opposite sides of the semi-reflective surface, for reflecting the first image light D1 and the second image light D2 respectively;
a shutter group 8 disposed between the mirror module 4 and the half mirror 9, wherein shutters 81 and 82 are disposed in front of the two symmetrically disposed mirrors 41 and 42, respectively, when the first image light D1 is projected, the shutter 81 is opened to allow the partially reflected first image light D1 to be projected after being directed to the mirror 41, and the other shutter 82 is closed to allow the partially transmitted first image light D1 to be blocked and absorbed; when the second image light D2 is projected, the shutter 82 is opened to allow a portion of the transmitted second image light D2 to be projected after being directed to the mirror 42, and the other shutter 81 is closed to allow a portion of the reflected second image light D2 to be blocked and absorbed;
a reflective diffusion sheet 5 having a plurality of micro-curved mirrors arranged in an array, wherein the optical paths between the first image light D1 and the second image light D2 split by the half mirror 9 and then reach the reflective diffusion sheet 5 are symmetrically arranged, and because the angles of incidence of the first image light D1 and the second image light D2 to the reflective diffusion sheet 5 are different, the micro-curved mirrors reflect and diffuse the first image light D1 to one of the eye receiving ranges, and the micro-curved mirrors reflect and diffuse the second image light D2 to the other eye receiving range.
As shown in fig. 17A, 17B and 18, since the shutter set 8 can effectively deal with the problem of light leakage, the combination of the polarization modulator 2 and the polarization beam splitter 3 in the first embodiment can be replaced by the half-mirror 9 with half-reflection and half-transmission (e.g. 50% reflection/50% transmission), the two shutters 81 and 82 are opened and closed at opposite timings, and the timing is synchronized with the time-sharing and alternate projection of the first image light D1 and the second image light D2 by the projection module 1, so as to achieve the effect similar to that of the first embodiment. Therefore, the polarization modulator 2 is not disposed in front of the projection module 1, and directly projects on the half mirror 9, when the projection module 1 projects the first image light D1, the first image light D1 reaches the two shutters 81 and 82 simultaneously, wherein the shutters 81 are opened, the first image light D1 reflected by the half mirror 9 is emitted to the mirror 41 and reflected to the reflective diffuser 5, the reflective diffuser 5 reflects and diffuses the first image light D1 to a first region R1, the first region R1 extends to one of the eye receiving ranges, and the other shutter 82 is closed, so that the first image light D1 penetrating through the half mirror 9 is blocked and absorbed; when the projection module 1 projects the second image light D2, the second image light D2 reaches the two shutters 81 and 82 simultaneously, wherein the shutters 82 are opened, the second image light D2 penetrating through the half mirror 9 is emitted to the reflector 42 and reflected to the reflective diffusion sheet 5, the reflective diffusion sheet 5 reflects and diffuses the second image light D2 to a second region R2, the second region R2 extends to correspond to another eye receiving range, and the other shutter 81 is closed, so that the second image light D2 reflected by the half mirror 9 is blocked and absorbed.
Although approximately half of the light is blocked and absorbed by the closed shutter group 8, so that the light utilization rate is reduced to below 50%, the polarization modulator 2 of the first embodiment has a similar phenomenon, and the transmittance of the polarization modulator 2 is also lower than 50%. The design of the half-reflecting mirror 9, the shutter group 8 and the symmetrical light path is matched, the polarization modulator 2 and the polarization beam splitter 3 are omitted, the cost can be reduced, and the effect of no light leakage can be achieved.
As shown in fig. 19, the display device further includes a windshield 7 and a concave mirror 6, the concave mirror 6 is disposed between the reflective diffuser 5 and the windshield 7, the reflective diffuser 5 reflects and diffuses the first image light D1 and the second image light D2 to the concave mirror 6, the concave mirror 6 reflects the first image light D1 and the second image light D2 to the windshield 7, and the windshield 7 reflects the first image light D1 and the second image light D2 to the receiving ranges of the first eye E1 and the second eye E2, respectively.
As shown in fig. 20 to 23, a third embodiment of a symmetric optical path 3D head-up display includes:
a projection module 1 having an imaging lens 10 for alternately projecting a first image light D1 and a second image light D2 at different times;
a reflective rotary beam splitter, which is a rotary shutter 85 and has a rotary beam splitting surface 850, defining a reflective region 851 and a transmissive region 852 by taking a rotation axis as a center, wherein the reflective region 851 and the transmissive region 852 are alternately located on the projection path of the projection module, so that the reflective region 851 reflects the first image light D1 and the second image light D2 penetrates the transmissive region;
a reflector module 4, which is two reflectors 41 and 42 symmetrically disposed on the rotating splitting surface 850 and located on two opposite sides of the rotating splitting surface 850 to reflect the first image light D1 and the second image light D2, respectively;
a reflective diffusion sheet 5 having a plurality of micro-curved mirrors arranged in an array, wherein the optical paths between the first image light D1 and the second image light D2 after being split by the rotary shutter 85 and reaching the reflective diffusion sheet 5 are symmetrically arranged, and because the angles of incidence of the first image light D1 and the second image light D2 to the reflective diffusion sheet 5 are different, the micro-curved mirrors reflect and diffuse the first image light D1 to the receiving range of the first eye E1, and the micro-curved mirrors reflect and diffuse the second image light D2 to the receiving range of the second eye E2.
As shown in fig. 20A, the rotary shutter 85 is a disc type shutter, and rotates clockwise or counterclockwise around the center point of the disc, and a part of the area is divided into a reflective area 851 and another part of the area is a transmissive area 852 by two radii passing through the center point of the disc. In this embodiment, the reflective region 851 and the transmissive region 852 are defined from both sides of the diameter of the center point of the disk. The reflective region 851 may be a silver or aluminum reflective surface, or a coating for increasing reflectivity, and the transmissive region 852 may be a transparent material such as glass, resin or crystal, or a coating for increasing transmissivity; the polarization modulator 2 and the combination of the polarization beam splitter 3 and the two shutters 41 and 42 are replaced by a rotary shutter 85, which is placed at the position of the polarization beam splitter 3, and the rotation speed of the rotary shutter 85 is synchronized with the timing of the projection module 1 projecting the first image light D1 and the second image light D2 alternately in time division. As shown in fig. 20B, when the projection module 1 projects the first image light D1, the rotating shutter 85 rotates the reflective region 851 to the projection path of the projection module 1, and the first image light D1 is reflected by the reflective region 851. As shown in fig. 20C, when the projection module 1 projects the second image light D2, the rotating shutter 85 rotates the transmissive area 852 to the projection path of the projection module 1, and the second image light D2 penetrates the transmissive area 852.
As shown in fig. 21A and 21B, when the projection module 1 projects the first image light D1, the rotary shutter 85 rotates the reflection region 851 to the projection path of the projection module 1, the reflection region 851 reflects the first image light D1 to the reflector 41, the reflector 41 reflects the first image light D1 to the reflective diffuser 5, the reflective diffuser 5 reflects and diffuses the first image light D1 to a first region R1, and the first region R1 extends to correspond to one of the eye receiving ranges.
As shown in fig. 22A and 22B, when the projection module 1 projects the second image light D2, the rotary shutter 85 rotates the transmissive region 852 to the projection path of the projection module 1, the second image light D2 penetrates the transmissive region 852 to the reflector 42, the reflector 42 reflects the second image light D2 to the reflective diffuser 5, the reflective diffuser 5 reflects and diffuses the second image light D2 to a second region R2, and the second region R2 extends to correspond to another eye receiving range.
As shown in fig. 23, the display device further includes a windshield 7 and a concave mirror 6, the concave mirror 6 is disposed between the reflective diffuser 5 and the windshield 7, the reflective diffuser 5 reflects and diffuses the first image light D1 and the second image light D2 to the concave mirror 6, the concave mirror 6 reflects the first image light D1 and the second image light D2 to the windshield 7, and the windshield 7 reflects the first image light D1 and the second image light D2 to the receiving ranges of the first eye E1 and the second eye E2, respectively.
The three implementation modes are that a single projection module is used, and a light splitter and a symmetrical light path are matched, so that the effect of clear binocular stereoscopic images is achieved. In a first embodiment, the image light is emitted from an imaging lens of the projection module, the image light is time-division modulated into two polarized image lights with mutually perpendicular polarization directions by the polarization modulator, and the two polarized image lights are separated by the polarization beam splitter in a reflection and penetration manner to form a left-eye polarized image light and a right-eye polarized image light.
The second embodiment uses a semi-reflective beam splitter instead of a combination of a polarization modulator and a polarization beam splitter, and matches a symmetrical optical path structure to achieve a clear binocular stereoscopic image effect.
In the third embodiment, a reflective rotary beam splitter is used to replace the combination of a polarization modulator, a polarization beam splitter and two shutters, and a symmetrical optical path structure is matched to achieve a clear binocular stereoscopic image effect.
It should be noted that in the above three embodiments, the two optical paths of the image light (the polarized image light L1& L2, the image light D1& D2) after being split by the beam splitter (the polarized beam splitter 3, the half mirror 9, and the rotary shutter 85) pass through the mirrors 41 and 42 and reach the reflective diffusion sheet 5, and are mutually symmetrical optical paths, so that the lengths of the left and right eye image optical paths can be maintained the same when the virtual image projection distance is long or the magnification is high, clear images are displayed on the reflective diffusion sheet 5, and a clear binocular stereoscopic image effect is projected.
Claims (10)
1. A symmetric optical path 3D heads-up display, comprising:
the projection module is provided with an imaging lens and alternately projects a first image light and a second image light in a time-sharing manner;
a polarization modulator for modulating the first image light into a first polarized image light and modulating the second image light into a second polarized image light, the polarization directions of the first polarized image light and the second polarized image light being perpendicular to each other;
a polarizing beam splitter having a light splitting surface for reflecting the first polarized image light and allowing the second polarized image light to pass therethrough;
the reflector module is two reflectors which are symmetrically arranged on the light splitting surface and positioned on two opposite sides of the light splitting surface and respectively reflect the first polarized image light and the second polarized image light;
a reflective diffusion sheet having a plurality of micro-curved mirrors arranged in an array, wherein the incident angles of the first polarized image light and the second polarized image light to the reflective diffusion sheet are different, the plurality of micro-curved mirrors reflect and diffuse the first polarized image light to a first eye receiving range, and the plurality of micro-curved mirrors reflect and diffuse the second polarized image light to a second eye receiving range;
the first image light and the second image light form mutually symmetrical optical paths after the light splitting of the polarizing light splitter and before the light is projected to the reflective diffusion sheet.
2. The 3D head-up display with a symmetrical light path as claimed in claim 1, further comprising a windshield and a concave mirror, wherein the concave mirror is disposed between the reflective diffuser and the windshield, the reflective diffuser reflects and diffuses the first polarized image light and the second polarized image light to the concave mirror, the concave mirror reflects the first polarized image light and the second polarized image light to the windshield, and the windshield reflects the first polarized image light and the second polarized image light to the first eye receiving range and the second eye receiving range respectively.
3. The 3D head-up display with symmetric optical paths as claimed in claim 1, further comprising a set of shutters disposed between the mirror module and the polarizing beam splitter, wherein a respective shutter is disposed between the two mirrors and the polarizing beam splitter, the two shutters are opened and closed at opposite timing sequences, and the timing sequences and the projection module alternately project the first image light and the second image light in time-sharing synchronization.
4. The symmetric optical path 3D heads-up display of claim 1 wherein the polarizing beam splitter is a reflective polarizer.
5. The symmetric optical path 3D heads-up display of claim 1 wherein the polarizing beamsplitter is a polarizing beamsplitter.
6. A symmetric optical path 3D heads-up display, comprising:
the projection module is provided with an imaging lens and alternately projects a first image light and a second image light in a time-sharing manner;
a semi-reflective beam splitter, which is a semi-reflective mirror having a semi-reflective surface, partially reflecting the first image light and the second image light, and allowing the first image light and the second image light to partially penetrate;
the reflector module is two reflectors which are symmetrically arranged on the semi-reflecting surface and positioned on two opposite sides of the semi-reflecting surface and respectively reflect the first image light and the second image light;
a shutter set, set between the reflector module and the half-reflecting mirror, setting a respective shutter between the two symmetrically placed reflectors and the half-reflecting mirror, the two shutters opening and closing at an opposite time sequence, the time sequence and the projection module alternately projecting the first image light and the second image light synchronously at a time-sharing time, when projecting one of the image lights, one of the shutters opens to let the image light irradiate to one of the reflectors, the other shutter closes to let the image light be blocked and absorbed, and can not reach the other reflector;
a reflective diffusion sheet having a plurality of micro-curved mirrors arranged in an array, wherein the first image light and the second image light are incident to the reflective diffusion sheet at different angles, the plurality of micro-curved mirrors reflect and diffuse the first image light to a first eye receiving range, and the plurality of micro-curved mirrors reflect and diffuse the second image light to a second eye receiving range;
the first image light and the second image light are symmetrical to each other in light path formed after the light is split by the semi-reflective light splitter and before the light is projected onto the reflective diffusion sheet.
7. The 3D head-up display with symmetrical light paths as claimed in claim 6, further comprising a windshield and a concave mirror, wherein the concave mirror is disposed between the reflective diffuser and the windshield, the reflective diffuser reflects and diffuses the first image light and the second image light to the concave mirror, the concave mirror reflects the first image light and the second image light to the windshield, and the windshield reflects the first image light and the second image light to the first eye receiving range and the second eye receiving range respectively.
8. A symmetric optical path 3D heads-up display, comprising:
the projection module is provided with an imaging lens and alternately projects a first image light and a second image light in a time-sharing manner;
a reflection rotary light splitter, which is a rotary shutter and has a rotary light splitting surface to define a reflection region and a transmission region, wherein the reflection region and the transmission region are alternately positioned on the projection path of the projection module to make the reflection region reflect the first image light or make the second image light penetrate the transmission region;
the reflector module is two reflectors which are symmetrically arranged on the rotating light splitting surface and positioned on two opposite sides of the rotating light splitting surface and respectively reflect the first image light and the second image light;
a reflective diffusion sheet having a plurality of micro-curved mirrors arranged in an array, wherein the first image light and the second image light are incident to the reflective diffusion sheet at different angles, the plurality of micro-curved mirrors reflect and diffuse the first image light to a first eye receiving range, and the plurality of micro-curved mirrors reflect and diffuse the second image light to a second eye receiving range;
the first image light and the second image light form symmetrical light paths after being split by the reflection rotary light splitter and before being projected to the reflection diffusion sheet.
9. The 3D head-up display with symmetrical light paths as claimed in claim 8, further comprising a windshield and a concave mirror, wherein the concave mirror is disposed between the reflective diffuser and the windshield, the reflective diffuser reflects and diffuses the first image light and the second image light to the concave mirror, the concave mirror reflects the first image light and the second image light to the windshield, and the windshield reflects the first image light and the second image light to the first eye receiving range and the second eye receiving range respectively.
10. The symmetrical optical path 3D head-up display of claim 8, wherein the rotary shutter is a disk-type shutter and rotates around a center point of a disk such that the reflective region and the transmissive region are alternately located on a projection path of the projection module, and the rotation speed of the disk and the time sequence of the projection module projecting the first image light and the second image light alternately are synchronized.
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Cited By (1)
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| CN115469462A (en) * | 2022-11-03 | 2022-12-13 | 泽景(西安)汽车电子有限责任公司 | Head-up display and head-up display equipment |
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