Head-up display device with eye box adjusted by backlight toroidal mirror

Abstract

To provide a head-up display device with an eye box adjusted by a backlight toroidal mirror.SOLUTION: A head-up display device is adapted to a use in combination with an image formation half-mirror, and is configured that include: a backlight source; a backlight toroidal mirror; a display panel; and an image formation concave surface mirror. The backlight toroidal mirror is rotatable, has an X-axis curvature and a Y-axis curvature different from the X-axis curvature, and can reflect a backlight beam of the backlight source. The backlight beam reflected by the backlight toroidal mirror is configured to form a backlight source real image at a position of an eye after passing through the display panel, in which the backlight source real image is an eye box. Since the backlight toroidal mirror rotates, and thereby the eye-box expands or contracts, the backlight source real image is still kept within the eye box even if the eye of an observer moves back and force.SELECTED DRAWING: Figure 14B

Description

[Technical field]

[0001] The present invention relates to a head-up display, and more particularly to a head-up display device with eyebox adjusted by backlight toroidal mirror. [Background technology]

[0002] Conventionally, a backlight concave mirror Mr_BL is used to reflect a backlight light source Lt_BL emitted by a backlight light source BL to form a backlight beam Bm_BL, and a backlight light source virtual image BL_im is formed behind the backlight concave mirror Mr_BL. The backlight beam Bm_BL passes through a display panel DP to form an image beam Bm_G, which is reflected by an imaging concave mirror Mr_F, and the display panel DP forms an image virtual image DP_im behind the imaging concave mirror Mr_F, and the backlight light source virtual image BL_im forms a backlight light source real image BL_re in front of the imaging concave mirror Mr_F (see Figures 1A and 1B).

[0003] After the image virtual image DP_im behind the imaging concave mirror Mr_F is reflected by the imaging half mirror Mr_SR, an image virtual image DP_im is formed in front of the vehicle. After the backlight light source real image BL_re in front of the imaging concave mirror Mr_F is reflected by the imaging half mirror Mr_SR, a backlight light source real image BL_re is formed at the observer's eye E, that is, the eye box EB.

[0004] The imaging half mirror Mr_SR is a windshield as shown in FIG. 1A or a combiner as shown in FIG. 1B.

[0005] As shown in FIG. 1C, when the observer's eye E moves back and forth, the original position of the eye box EB does not overlap with the moved eye E, and the image observed by the observer becomes unclear, the image is lost, and sometimes the image becomes invisible.

[0006] Therefore, the present inventors believed that the above-mentioned drawbacks could be improved, and as a result of extensive research, they came to propose the present invention, which effectively improves the above-mentioned problems through rational design.

[0007] The present invention has been made in view of the above circumstances, and aims to solve the above problems, i.e., to provide a head-up display that adjusts the eyebox with a backlight toroidal mirror so that a complete image can be clearly observed even if the observer's eyes move back and forth. Summary of the Invention [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following means. According to one aspect of the present invention, there is provided a head-up display for adjusting an eyebox with a backlight toroidal mirror, the head-up display including: a backlight light source adapted to be used in combination with an imaging half mirror and for projecting a backlight beam; a backlight toroidal mirror that is rotatable and has an X-axis curvature and a Y-axis curvature, the X-axis curvature being different from the Y-axis curvature, the backlight toroidal mirror being used to reflect the backlight beam of the backlight light source; a display panel arranged to display an image and transmit the backlight beam reflected by the backlight toroidal mirror to form an image beam; and an imaging concave mirror arranged to reflect the image beam to the imaging half mirror, to form a display panel virtual image at one side of the imaging half mirror away from a viewer, and to form a backlight light source real image at one side of the imaging half mirror closer to the viewer and at the position of the viewer's eyes, the backlight light source real image being the eyebox. An off-axis optical path is between the backlight light source and the backlight toroidal mirror, the backlight light source is reflected by the X-axis curvature so as to be focused on the X-axis backlight focal plane, the backlight light source is reflected by the Y-axis curvature so as to be focused on the Y-axis backlight focal plane, the range of the eyebox is from the X-axis backlight focal plane to the Y-axis backlight focal plane, and the range of the eyebox extends or contracts on the imaging optical path of the backlight light source real image by rotating the backlight toroidal mirror, so that the observer's eyes are still kept within the eyebox when moving on the imaging optical path of the backlight light source real image.

[0009] In a preferred embodiment of the present invention, the backlight toroidal mirror rotates about its central axis.

[0010] In a preferred embodiment of the present invention, when an included angle in the Y-axis direction exists between the optical axis of the backlight beam and the central axis of the backlight toroidal mirror, the backlight toroidal mirror rotates by a rotation angle around its central axis, and the X-axis curvature of the surface of the backlight toroidal mirror on which the backlight beam is irradiated is smaller than the Y-axis curvature, the range of the eyebox expands as the rotation angle increases from 0 degrees to 90 degrees, and the range of the eyebox contracts as the rotation angle decreases from 90 degrees to 0 degrees.

[0011] In a preferred embodiment of the present invention, when an included angle in the Y-axis direction exists between the optical axis of the backlight beam and the central axis of the backlight toroidal mirror, the backlight toroidal mirror rotates by a rotation angle around its central axis, and the X-axis curvature of the surface of the backlight toroidal mirror on which the backlight beam is irradiated is greater than the Y-axis curvature, the range of the eyebox shortens as the rotation angle increases from 0 degrees to 90 degrees, and the range of the eyebox expands as the rotation angle decreases from 90 degrees to 0 degrees.

[0012] In a preferred embodiment of the present invention, when an included angle in the X-axis direction exists between the optical axis of the backlight beam and the central axis of the backlight toroidal mirror, the backlight toroidal mirror rotates by a rotation angle around its central axis, and the X-axis curvature of the surface of the backlight toroidal mirror on which the backlight beam is irradiated is smaller than the Y-axis curvature, the range of the eyebox shortens as the rotation angle increases from 0 degrees to 90 degrees, and the range of the eyebox expands as the rotation angle decreases from 90 degrees to 0 degrees.

[0013] In a preferred embodiment of the present invention, when an included angle in the X-axis direction exists between the optical axis of the backlight beam and the central axis of the backlight toroidal mirror, the backlight toroidal mirror rotates by a rotation angle around its central axis, and the X-axis curvature of the surface of the backlight toroidal mirror on which the backlight beam is irradiated is greater than the Y-axis curvature, the range of the eyebox expands as the rotation angle increases from 0 degrees to 90 degrees, and the range of the eyebox contracts as the rotation angle decreases from 90 degrees to 0 degrees.

[0014] In a preferred embodiment of the present invention, when the backlight toroidal mirror rotates to extend the range of the eyebox, the brightness of the backlight source is increased.

[0015] In a preferred embodiment of the present invention, when the backlight toroidal mirror rotates to reduce the range of the eyebox, the brightness of the backlight light source decreases.

[0016] In a preferred embodiment of the present invention, the imaging half mirror is a windshield or combiner, and is used to partially reflect the image beam from the imaging concave mirror to the observer's eye, and at the same time partially transmit light rays of the scene in front of it to the observer's eye.

[0017] Other features of the present invention will become apparent from the following detailed description of the present invention and the accompanying drawings. [Brief description of the drawings]

[0018] [Figure 1A] FIG. 1 is a schematic diagram showing a conventional head-up display that uses a windshield for projection. [Figure 1B] FIG. 1 is a schematic diagram showing a head-up display projected using a conventional combiner. [Figure 1C] 1B is a schematic diagram showing forward and backward movement of the viewer's eye position in the conventional head-up display shown in FIG. 1A. FIG. [Figure 2A]FIG. 1 is a schematic diagram showing a configuration of a backlight toroidal mirror used in a head-up display according to an embodiment of the present invention. [Figure 2B] FIG. 1 is a schematic diagram showing a configuration of a backlight toroidal mirror used in a head-up display according to an embodiment of the present invention. [Figure 3A] FIG. 2 is a schematic diagram showing equivalent focal lengths on the X-axis and Y-axis for different angles of incidence of a backlight toroidal mirror according to an embodiment of the present invention. [Figure 3B] FIG. 2 is a schematic diagram showing equivalent focal lengths on the X-axis and Y-axis for different angles of incidence of a backlight toroidal mirror according to an embodiment of the present invention. [Figure 3C] FIG. 2 is a schematic diagram showing equivalent focal lengths on the X-axis and Y-axis for different angles of incidence of a backlight toroidal mirror according to an embodiment of the present invention. [Figure 4] 1 is a schematic diagram showing a real image formation state when a point light source according to an embodiment of the present invention is on the central axis of a backlight toroidal mirror and the object distance is longer than the focal length. FIG. [Diagram 5] 1 is a schematic diagram showing a virtual image formation state when a point light source according to an embodiment of the present invention is on the central axis of a backlight toroidal mirror and the object distance is shorter than the focal length. FIG. [Figure 6] 1 is a schematic diagram showing a real image formation state when a rectangular light source according to an embodiment of the present invention is located on the central axis of a backlight toroidal mirror and the object distance is longer than the focal length. FIG. [Figure 7] 1 is a schematic diagram showing a real image formation state when a rectangular light source according to an embodiment of the present invention is shifted on the Y axis from the central axis of a backlight toroidal mirror and the object distance is longer than the equivalent focal length. FIG. [Figure 8] FIG. 8 is a schematic diagram showing a real image formation state when the backlight toroidal mirror of FIG. 7 according to one embodiment of the present invention is rotated 90 degrees. [Figure 9] 1 is a schematic diagram showing a virtual image formation state when a rectangular light source according to an embodiment of the present invention is located on the central axis of a backlight toroidal mirror and the object distance is smaller than the focal length. FIG. [Figure 10] 1 is a schematic diagram showing a virtual image formation state when a rectangular light source according to an embodiment of the present invention is shifted on the Y axis from the central axis of a backlight toroidal mirror and the object distance is less than the equivalent focal length. FIG. [Figure 11] FIG. 11 is a schematic diagram showing a virtual image formation state when the backlight toroidal mirror of FIG. 10 according to one embodiment of the present invention is rotated 90 degrees. [Figure 12] 13 is a list showing the different off-axis directions, different rotation angle degree changes, and corresponding backlight source real image stretching or shortening according to different backlight toroidal mirror curvature configurations according to one embodiment of the present invention. [Figure 13A] FIG. 2 is a schematic diagram showing the eyebox displayed when the backlit toroidal mirror is not rotating in accordance with one embodiment of the present invention. [Figure 13B] FIG. 2 is a schematic diagram showing the eyebox displayed when the backlit toroidal mirror is not rotating in accordance with one embodiment of the present invention. [Figure 13C] FIG. 13 is a schematic diagram of a backlight toroidal mirror rotating to stretch the eyebox as the observer moves back and forth in accordance with one embodiment of the present invention. [Figure 14A] FIG. 2 is a schematic diagram illustrating a small eyebox formed when a backlight source according to one embodiment of the present invention is placed off-axis relative to the Y-axis of a backlight toroidal mirror. [Figure 14B] FIG. 14B is a schematic diagram illustrating the elongated eyebox formed when the backlight toroidal mirror of FIG. 14A is rotated 90 degrees in accordance with one embodiment of the present invention. [Figure 15A] 1 is a schematic diagram showing a slightly larger eye box formed when a backlight light source according to an embodiment of the present invention is installed off-axis of the Y-axis of a backlight toroidal mirror. FIG. [Figure 15B] FIG. 15B is a schematic diagram illustrating the elongated eyebox formed when the backlight toroidal mirror of FIG. 15A is rotated 45 degrees in accordance with one embodiment of the present invention. [Figure 15C]FIG. 15B is a schematic diagram illustrating the elongated eyebox formed when the backlight toroidal mirror of FIG. 15A is rotated 90 degrees in accordance with one embodiment of the present invention. [Figure 16A] 1 is a schematic diagram showing a small eyebox formed when a backlight source according to an embodiment of the present invention is disposed off-axis of the X-axis of a backlight toroidal mirror. FIG. [Figure 16B] FIG. 16B is a schematic diagram illustrating the elongated eyebox formed when the backlight toroidal mirror of FIG. 16A is rotated 90 degrees in accordance with one embodiment of the present invention. [Figure 17A] FIG. 1 is a schematic diagram showing a slightly larger eye box formed when a backlight light source according to an embodiment of the present invention is installed off-axis of the X-axis of a backlight toroidal mirror. [Figure 17B] FIG. 17B is a schematic diagram illustrating the elongated eyebox formed when the backlight toroidal mirror of FIG. 17A is rotated 45 degrees in accordance with one embodiment of the present invention. [Figure 17C] FIG. 17B is a schematic diagram illustrating the elongated eyebox formed when the backlight toroidal mirror of FIG. 17A is rotated 90 degrees in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, the embodiments of the present invention will be described in detail. However, the present invention is not limited to these, and various modifications are possible within the scope of the description. The embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present invention.

[0020] Next, a head-up display in which an eyebox is adjusted using a backlight toroidal mirror according to the present invention will be described with reference to FIGS. 2A to 17C.

[0021] The head-up display for adjusting an eye box EB with a backlight toroidal mirror according to the present invention is suitable for use in combination with an imaging semi-reflective mirror Mr_SR, and includes a backlight source BL, a backlight toroidal mirror TMR, a display panel DP, and an imaging concave mirror Mr_F. The imaging semi-reflective mirror Mr_SR may be a windshield as shown in FIG. 1A or a combiner as shown in FIG. 1B. The following description will be given taking the imaging semi-reflective mirror Mr_SR as a windshield as an example.

[0022] The backlight source BL projects a backlight beam onto the backlight toroidal mirror TMR. The head-up display is designed with an off-axis light path and a non-coaxial light path, so that the image is kept clear and undistorted. Therefore, the backlight concave mirror and the imaging concave mirror used are both concave mirrors with two kinds of curvature, that is, toroidal mirrors. The backlight light source BL and the backlight toroidal mirror TMart are off-axis light paths, and the included angle between the optical axis of the backlight beam and the central axis of the backlight toroidal mirror TMart is greater than 0 degrees and less than 90 degrees, and the backlight toroidal mirror TMart is rotatable and has an X-axis curvature and a Y-axis curvature. The X-axis curvature refers to the curvature on the axial direction X, and the Y-axis curvature refers to the curvature on the axial direction Y, and the X-axis curvature is different from the Y-axis curvature. The backlight toroidal mirror TMart reflects the backlight beam of the backlight light source BL to the display panel DP. The backlight toroidal mirror TMart may be a backlight toroidal mirror TMart as shown in Fig. 2A, in which the focal length FL_x corresponding to the X-axis curvature is larger than the focal length FL_y corresponding to the Y-axis curvature, or may be a toroidal mirror TMart as shown in Fig. 2B, in which the focal length FL_x corresponding to the X-axis curvature is smaller than the focal length FL_y corresponding to the Y-axis curvature.

[0023] The display panel DP displays an image and transmits a backlight beam from a backlight toroidal mirror TMR to form an image beam.

[0024] The imaging concave mirror Mr_F reflects the image beam to the imaging half mirror Mr_SR, which forms a display panel virtual image on one side of the imaging half mirror Mr_SR that is far from the viewer, and forms backlight light source real images (BL_re1 to BL_re15) on one side of the imaging half mirror Mr_SR that is closer to the viewer and at the viewer's eye position. This backlight light source real image is the eye box EB.

[0025] As the backlight toroidal mirror T Gr rotates, the eye box EB expands or contracts on the optical path for forming the real image of the backlight light source, so that the observer's eye remains within the eye box EB when moving on the optical path for forming the real image of the backlight light source.

[0026] The operation and principle of the backlight toroidal mirror TMR will now be described with an example. As shown in FIG. 3A, when a light ray Lt travels along the central axis CA of the backlight toroidal mirror TMR, the focal length FL_x of the focus Fx in the axial direction X is greater than the focal length FL_y of the focus Fy in the axial direction Y.

[0027] As shown in Fig. 3B, when the optical path of the light ray Lt rotates in the axial direction Y by an angle θy greater than 0 degrees with the center of the backlight toroidal mirror TMR as a pivot point, the equivalent focal length FL_x1 corresponding to the X-axis curvature is shortened to FL_x × cosθy, and the equivalent focal length FL_y1 corresponding to the Y-axis curvature is extended to FL_y / cosθy. By designing the suitable focal lengths FL_x and FL_y and the angle θy, the equivalent focal length FL_x1 is approximately equal to the equivalent focal length FL_y1, that is, FL_x × cosθy ≒ FL_y / cosθy.

[0028] As shown in FIG. 3C, when the backlight toroidal mirror TMR in FIG. 3B is rotated 90 degrees around its central axis CA as the center of rotation and the value of the X-axis curvature is replaced by the value of the Y-axis curvature, the equivalent focal length FL_x2 corresponding to the X-axis curvature becomes shorter, FL_y×cosθy, and the equivalent focal length FL_y2 corresponding to the Y-axis curvature becomes longer, FL_x / cosθy, i.e., FL_x / cosθy>FL_x>FL_y>FL_y×cosθy.

[0029] In a situation where a point light source P forms a real image in front of the backlight toroidal mirror TMart (see FIG. 4), when the point light source P is on the central axis CA of the backlight toroidal mirror TMart, the focal length FL_x of the focal point Fx corresponding to the X-axis curvature is larger than the focal length FL_y of the focal point Fy corresponding to the Y-axis curvature, and the distance from the point light source P to the backlight toroidal mirror TMart is larger than the focal length FL_x and larger than the focal length FL_y. Because the distance from the point light source P to the focal point Fx is short and the distance from the focal point Fy is long, the light emitted by the point light source P is reflected by the surface of the X-axis curvature on the backlight toroidal mirror TMart and then focused at position q1, and the light emitted by the point light source P is reflected by the surface of the Y-axis curvature on the backlight toroidal mirror TMart and then focused at position q2. The distance from position q1 to the backlight toroidal mirror TMart is larger than the distance from position q2 to the backlight toroidal mirror TMart.

[0030] Before the light reflected by the surface of the X-axis curvature reaches position q1, it passes through position q2 and is not focused. After the light reflected by the surface of the Y-axis curvature is focused at position q2, it starts to diverge forward and then passes through position q1. The circle of least confusion is located at position q3 between positions q1 and q2. Therefore, the area where the light on the central axis CA has the highest brightness is the area from position q1 to position q2, and the brightness of the light decreases in both other areas before and after this area.

[0031] In a situation where a point light source P forms a virtual image behind the backlight toroidal mirror TMart (see FIG. 5), when the point light source P is on the central axis CA of the backlight toroidal mirror TMart, the focal length FL_x of the focal point Fx is smaller than the focal length FL_y of the focal point Fy, and the distance from the point light source P to the backlight toroidal mirror TMart is smaller than the focal length FL_x and smaller than the focal length FL_y. Because the distance from the point light source P to the focal point Fx is short and the distance from the focal point Fy is long, the virtual image light rays generated by the light emitted by the point light source P being extended backward when reflected by the surface of the X-axis curvature on the backlight toroidal mirror TMart are focused at position q4, and the virtual image light rays generated by the light emitted by the point light source P being extended backward when reflected by the surface of the Y-axis curvature on the backlight toroidal mirror TMart are focused at position q5. The distance from position q4 to the backlight toroidal mirror TMart is greater than the distance from position q5 to the backlight toroidal mirror TMart.

[0032] The virtual image light rays generated by extending the light rays reflected by the surface with the X-axis curvature toward the rear first converge at position q4 at the portion far from the rear, and then diverge toward the front and pass through position q5. The virtual image light rays generated by extending the light rays reflected by the surface with the Y-axis curvature toward the rear first pass through position q4 before converge at position q5 at the portion far from the rear, and are not converged. Since the circle of least confusion is located at position q6 between positions q4 and q5, the region where the brightness of the virtual image light rays on the central axis CA is the highest is the region from position q4 to position q5, and the brightness of the virtual image light rays decreases in both other regions before and after this region.

[0033] In a situation where a surface light source forms a real image in front of the backlight toroidal mirror TMart (see FIG. 6), when a rectangular backlight light source BL is on the central axis CA of the backlight toroidal mirror TMart, the focal length FL_x of the focus Fx corresponding to the X-axis curvature is greater than the focal length FL_y of the focus Fy corresponding to the Y-axis curvature, and the distance from the backlight light source BL to the backlight toroidal mirror TMart is greater than the focal length FL_x, which is greater than the focal length FL_y. Since the distance from the backlight light source BL to the focal point Fx is short and the distance to the focal point Fy is long, the light emitted by the backlight light source BL is reflected by the surface of the X-axis curvature on the backlight toroidal mirror TMart and then focused at position q7, i.e., the X-axis backlight focal plane FPX has high brightness in the axial direction X close to the central axis CA, and the light emitted by the backlight light source BL is reflected by the surface of the Y-axis curvature on the backlight toroidal mirror TMart and then focused at position q8, i.e., the Y-axis backlight focal plane FPY has high brightness in the axial direction Y close to the central axis CA. The distance from position q7 to the backlight toroidal mirror TMart is greater than the distance from position q8 to the backlight toroidal mirror TMart.

[0034] Before the light reflected by the surface with the X-axis curvature reaches position q7, it first passes through position q8 and is not focused. After the light reflected by the surface with the Y-axis curvature is focused at position q8, it diverges forward and passes through position q7. Therefore, the region where the brightness of the light near the central axis CA is the highest is the region from position q7 to position q8, and at position q7, the brightness in the axial direction X close to the central axis CA is high, and at position q8, the brightness in the axial direction Y of the central axis CA is high, and the brightness of the light decreases in both other regions before and after the region from position q7 to position q8.

[0035] Therefore, after the light emitted by the backlight source BL is reflected by the backlight toroidal mirror TMart, a single backlight source real image BL_re1 with an expanded area and extended range (depth) is formed in front of the backlight toroidal mirror TMart.

[0036] As shown in FIG. 7, when the rectangular backlight source BL rotates in the axial direction Y at an angle θy1 with the center of the backlight toroidal mirror TMart as a pivot point (i.e., the included angle between the optical axis of the backlight beam of the backlight source BL in the axial direction Y and the central axis CA of the backlight toroidal mirror TMart is angle θy1), the equivalent focal length FL_x2 corresponding to the X-axis curvature is shortened to FL_x×cosθy1, and the equivalent focal length FL_y2 corresponding to the Y-axis curvature is extended to FL_y / cosθy1. If the focal lengths FL_x and FL_y and the angle θy1 are appropriately adjusted, there is a possibility that FL_x×cosθy1 becomes almost equal to FL_y / cosθy1. Under this condition, the light emitted by the backlight source BL is reflected by the backlight toroidal mirror TMart and then condensed at a position q9, forming a single backlight source real image BL_re2 with an expanded area, a small volume, and a bright overall image.

[0037] As shown in Fig. 8, when the backlight toroidal mirror TMR in Fig. 7 rotates 90 degrees around its central axis CA, the equivalent focal length FL_x3 corresponding to the X-axis curvature is shortened to FL_y × cosθy1, and the equivalent focal length FL_y3 corresponding to the Y-axis curvature is extended to FL_x / cosθy1, so that FL_x / cosθy1>FL_x>FL_y>FL_y × cosθy1. Under this condition, after the light emitted by the backlight source BL is reflected by the backlight toroidal mirror TMR, the area is expanded and the light becomes one backlight source real image BL_re3 with a longer range, which is from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY.

[0038] 9, when the rectangular backlight light source BL is on the central axis CA of the backlight toroidal mirror TMart, the focal length FL_x of the focal point Fx corresponding to the X-axis curvature is larger than the focal length FL_y of the focal point Fy corresponding to the Y-axis curvature, and the distance between the backlight light source BL and the backlight toroidal mirror TMart is smaller than the focal length FL_x and smaller than the focal length FL_y. Because the distance from the backlight light source BL to the focal point Fx is long and the distance from the backlight light source BL to the focal point FMart is short, the light beam emitted by the backlight light source BL is reflected by the surface of the X-axis curvature on the backlight toroidal mirror TMart and then extended backward, generating a virtual image light beam that is focused at a position q9, increasing the luminance in the axial direction X close to the central axis CA, and the light beam emitted by the backlight light source BL is reflected by the surface of the Y-axis curvature on the backlight toroidal mirror TMart and then extended backward, generating a virtual image light beam that is focused at a position q10, increasing the luminance in the axial direction Y close to the central axis CA. The distance between the position q9 and the backlight toroidal mirror TMR is smaller than the distance between the position q10 and the backlight toroidal mirror TMR.

[0039] The virtual image light rays generated by extending the light rays reflected by the surface with the X-axis curvature toward the rear first pass through position q10 and are not focused before being focused at position q9 from a point far from the rear. The virtual image light rays generated by extending the light rays reflected by the surface with the Y-axis curvature toward the rear are focused at position q10 from a point far from the rear, and then diverge toward the front and pass through position q9. The region where the luminance of the light on the central axis CA is the highest is the region from position q9 to position q10, and at position q9, the luminance in the axial direction X close to the central axis CA is high, and at position q10, the luminance in the axial direction Y close to the central axis CA is high, and the luminance of the light decreases in both other regions before and after the region from position q9 to position q10.

[0040] Therefore, after the light emitted by the backlight source BL is reflected by the backlight toroidal mirror TMart, a backlight source virtual image BL_im1 with an enlarged area and extended range is formed behind the backlight toroidal mirror TMart, and its range extends from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY.

[0041] As shown in Fig. 10, when the rectangular backlight source BL rotates in the axial direction Y at an angle θy2 with the center of the backlight toroidal mirror TMart as a pivot point, the equivalent focal length FL_x4 corresponding to the X-axis curvature is shortened to FL_x × cosθy2, and the equivalent focal length FL_y4 corresponding to the Y-axis curvature is extended to FL_y / cosθy2. By appropriately adjusting the focal lengths FL_x and FL_y and the angle θy2, it is possible that FL_x × cosθy2 is almost equal to FL_y / cosθy2. Under this condition, the light emitted by the backlight source BL is reflected by the backlight toroidal mirror TMart and then focused at a position q11, forming a single backlight source virtual image BL_im2 with an expanded area, a small volume, and a bright overall image.

[0042] 11, when the backlight toroidal mirror TMR in FIG. 10 rotates 90 degrees around its central axis CA, the equivalent focal length FL_x5 corresponding to the X-axis curvature is shortened to FL_y×cosθy2, and the equivalent focal length FL_y5 corresponding to the Y-axis curvature is extended to FL_x / cosθy2, so that FL_x / cosθy2>FL_x>FL_y>FL_y×cosθy2. Under this condition, the light emitted by the backlight source BL is reflected by the backlight toroidal mirror TMR, and the area is expanded to become one backlight source virtual image BL_im3 with a longer range, which is from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY.

[0043] FIG. 12 shows a table showing the change in the backlight light source real image elongating or shortening when the rotation angle changes from 0 degrees to 90 degrees or from 90 degrees to 0 degrees when the off-axis direction is the X-axis or the Y-axis, under the condition that the X-axis curvature of the backlight toroidal mirror is larger or smaller than the Y-axis curvature.

[0044] As can be seen from the above results, when the equivalent focal length of the backlight toroidal mirror TMart in the axial direction X and the axial direction Y is approximately the same (see FIG. 13A), the light emitted by the backlight source BL is reflected by the backlight toroidal mirror TMart and then concentrated as a single backlight source virtual image BL_im4 which is enlarged in area, small in volume, and bright overall. The backlight source virtual image BL_im4 is then reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form a single backlight source real image BL_re4 which is small in volume and bright overall, that is, the eye box EB.

[0045] When the equivalent focal length of the backlight toroidal mirror T Mart in the axial direction X is different from that in the axial direction Y (see FIG. 13B ), the light emitted by the backlight source BL is reflected by the backlight toroidal mirror T Mart and then concentrated into a single bright backlight source virtual image BL_im5 with an expanded area and a slightly larger volume. The backlight source virtual image BL_im5 is then reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form a single bright backlight source real image BL_re5 with a slightly longer range, that is, the eye box EB.

[0046] When using a head-up display, if the observer's eyes move back and forth, the eye box EB shown in Figures 13A and 13B cannot overlap with the eyes after the movement, and the image observed by the observer becomes unclear. At this time, the backlight toroidal mirror TMR rotates 90 degrees around its central axis CA as the center of rotation (see Figure 13C), and the eye box EB extends back and forth so that the eye box EB covers the observer's eyes after the movement, making it possible to observe a clear image.

[0047] Hereinafter, a head-up display in which the range of the eye box EB is adjusted by a backlight toroidal mirror TGr will be described as an example. <Example 1>

[0048] 14A, the Y-axis curvature of the backlight toroidal mirror TMR is larger than the X-axis curvature, and the focal length in the axial direction Y is smaller than the focal length in the axial direction X. The backlight light source BL is deflected downward in the axial direction Y at an angle θy3 from the central axis CA of the backlight toroidal mirror TMR. Under this condition, the backlight beam forms a single backlight light source virtual image BL_im6 behind the backlight toroidal mirror TMR, which is expanded in area, small in volume, and bright overall.

[0049] The light emitted by the backlight source virtual image BL_im6 passes through the display panel DP and is reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form a backlight source real image BL_re6 that is small in volume and bright overall, that is, the eye box EB, where the viewer's eyes overlap with the eye box EB.

[0050] As shown in FIG. 14B, the backlight toroidal mirror TMR in FIG. 14A rotates 90 degrees around its central axis CA, and the backlight beam from the backlight source BL forms a single backlight source virtual image BL_im7 with an extended range behind the backlight toroidal mirror TMR.

[0051] The light emitted by the backlight source virtual image BL_im7 passes through the display panel DP, and is reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form one backlight source real image BL_re7 with an extended range, that is, one eyebox EB with an extended front and rear. The range of this eyebox EB is from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY, and even if the viewer's eyes move back and forth, they are still kept within the eyebox EB.

[0052] This elongated eyebox EB has its luminance distributed within the elongated range, but by simply increasing the luminance of the backlight source, the image that the observer views within this elongated eyebox range still remains clear. <Example 2>

[0053] 15A, the Y-axis curvature of the backlight toroidal mirror TMR is larger than its X-axis curvature, and its focal length in the axial direction Y is smaller than its focal length in the axial direction X. The backlight light source BL is deflected downward in the axial direction Y at an angle θy4 from the central axis CA of the backlight toroidal mirror TMR. Under this condition, the backlight beam forms a single bright backlight light source virtual image BL_im8 with an expanded area and a slightly larger volume behind the backlight toroidal mirror TMR.

[0054] The light emitted by the backlight source virtual image BL_im8 passes through the display panel DP, and is reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form a backlight source real image BL_re8 that is somewhat long in range and bright overall, that is, the eyebox EB. The range of this eyebox EB is from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY, and the viewer's eyes stay within the eyebox EB.

[0055] As shown in FIG. 15B, the backlight toroidal mirror TMR in FIG. 15A rotates 45 degrees around its central axis CA, and the backlight beam of the backlight source BL forms a single backlight source virtual image BL_im9 with an extended range behind the backlight toroidal mirror TMR.

[0056] The light emitted by the backlight source virtual image BL_im9 passes through the display panel DP, and is reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form one backlight source real image BL_re9 with an extended range, that is, one eyebox EB with an extended front and rear. The range of this eyebox EB is from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY, and even if the viewer's eyes move back and forth a short distance, the viewer's eyes are still kept within the eyebox EB.

[0057] As shown in FIG. 15C, the backlight toroidal mirror TMR in FIG. 15A rotates 90 degrees around the central axis CA, and the backlight beam from the backlight source BL forms a single long-range backlight source virtual image BL_im10 behind the backlight toroidal mirror TMR.

[0058] The light emitted by the backlight source virtual image BL_im10 passes through the display panel DP, and is reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form one backlight source real image BL_re10 with an extended range, that is, one eyebox EB that is further extended forward and backward. The range of this eyebox EB is from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY, and even if the viewer's eyes move a long distance forward and backward, the viewer's eyes are still kept within the eyebox EB.

[0059] This further elongated eyebox EB has its luminance distributed within the further elongated range, but by simply increasing the luminance of the backlight source BL, the image that the observer views within this further elongated eyebox EB is still clearly maintained. <Example 3>

[0060] 16A, the X-axis curvature of the backlight toroidal mirror TMR is larger than the Y-axis curvature, and the focal length in the axial direction X is smaller than the focal length in the axial direction Y. The backlight light source BL is deflected at an angle θx5 to the right in the axial direction X from the central axis CA of the backlight toroidal mirror TMR. Under this condition, the backlight beam forms a single backlight light source virtual image BL_im11 behind the backlight toroidal mirror TMR, which has an expanded area, shallow range, and is bright overall.

[0061] The light emitted by the backlight source virtual image BL_im11 passes through the display panel DP, and is reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form a backlight source real image BL_re11 that is shallow in range and bright overall, that is, the eye box EB, where the viewer's eyes overlap.

[0062] As shown in FIG. 16B, the backlight toroidal mirror TMR in FIG. 16A rotates 90 degrees around its central axis CA, and the backlight beam of the backlight source BL forms a single backlight source virtual image BL_im12 with an extended range behind the backlight toroidal mirror TMR.

[0063] The light emitted by the backlight source virtual image BL_im12 passes through the display panel DP, and is reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form one backlight source real image BL_re12 with an extended range, that is, one eyebox EB with an extended front and rear. The range of this eyebox EB is from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY, and even if the viewer's eyes move back and forth, the viewer's eyes are still kept within the eyebox EB.

[0064] Although the brightness of this elongated eyebox EB is distributed within the elongated range, the image that the observer views within this elongated eyebox EB is still clearly maintained by simply increasing the brightness of the backlight source BL. <Example 4>

[0065] 17A, the X-axis curvature of the backlight toroidal mirror TMR is larger than the Y-axis curvature, and the focal length in the axial direction X is smaller than the focal length in the axial direction Y. The backlight light source BL is deflected at an angle θx6 to the right in the axial direction X from the central axis CA of the backlight toroidal mirror TMR. Under this condition, the backlight beam forms a single bright backlight light source virtual image BL_im13 behind the backlight toroidal mirror TMR, which has an expanded area and a slightly longer range.

[0066] The light emitted by the backlight source virtual image BL_im13 passes through the display panel DP, and is reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form a backlight source real image BL_re13 that is somewhat long in range and bright overall, that is, the eyebox EB. The range of this eyebox EB is from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY. At this time, the viewer's eyes stay within the eyebox EB.

[0067] As shown in FIG. 17B, the backlight toroidal mirror TMR in FIG. 17A rotates 45 degrees around its central axis CA, and the backlight beam of the backlight source BL forms a single backlight source virtual image BL_im14 with an extended range behind the backlight toroidal mirror TMR.

[0068] The light emitted by the backlight source virtual image BL_im14 passes through the display panel DP, and is reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form one backlight source real image BL_re14 with an extended range, that is, one eyebox EB with an extended front and rear. The range of this eyebox EB is from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY, and even if the viewer's eyes move back and forth a short distance, the viewer's eyes are still kept within the eyebox EB.

[0069] As shown in FIG. 17C, the backlight toroidal mirror TMR in FIG. 17A rotates 90 degrees around its central axis CA, and the backlight beam from the backlight source BL forms a single long-range backlight source virtual image BL_im15 behind the backlight toroidal mirror TMR.

[0070] The light emitted by the backlight source virtual image BL_im15 passes through the display panel DP, and is reflected by the imaging concave mirror Mr_F and the imaging half mirror Mr_SR to form one backlight source real image BL_re15 with an extended range, that is, one eyebox EB further extended forward and backward. The range of this eyebox EB is from the X-axis backlight focal plane FPX to the Y-axis backlight focal plane FPY, and even if the viewer's eyes move back and forth a long distance, the viewer's eyes are still kept within the eyebox EB.

[0071] Although the brightness of this further elongated eyebox EB is distributed within the further elongated range, the image that the observer views within this further elongated eyebox EB is still clearly maintained by simply increasing the brightness of the backlight source BL.

[0072] In the situation of FIG. 17C, when the backlight toroidal mirror TMR rotates 45 degrees in the opposite direction around its central axis CA, the eyebox EB returns from the long range state to the slightly shortened range state of FIG. 17B.

[0073] In the state of FIG. 17C, when the backlight toroidal mirror TMR rotates 90 degrees in the opposite direction around its central axis CA, the eyebox EB returns from the long-range state to the short-range state of FIG. 17A.

[0074] In the present invention, the angle at which the backlight toroidal mirror TMart rotates at the original position may be any angle other than 45 degrees and 90 degrees. Different rotation angles result in different degrees of extension or contraction of the eyebox EB. For example, within the range of 0 degrees to 90 degrees, the larger the rotation angle, the larger the change in the range of the eyebox EB, and the smaller the rotation angle, the smaller the change in the range of the eyebox EB. The effect of an angle between 90 degrees and 180 degrees is the same as that between 90 degrees and 0 degrees. The effect of an angle between 180 degrees and 270 degrees is the same as that between 0 degrees and 90 degrees. The effect of an angle between 270 degrees and 360 degrees is the same as that between 90 degrees and 0 degrees.

[0075] In the present invention, the longer the eye box EB is extended, the more the luminance is dispersed and the greater the need for increased luminance of the backlight source BL. The shorter the eye box EB is shortened, the less the luminance is dispersed and the less the need for increased luminance of the backlight source BL.

[0076] In addition, the head-up display of the present invention further includes a controller (not shown), an eye tracking system (not shown), and a driving module (not shown). The controller is electrically connected to the eye tracking system, the driving module, the backlight source, and the display panel DP, and controls the operation of the driving module and the backlight source based on information provided by the eye tracking system.

[0077] The eye tracking system detects the degree of forward and backward displacement of the observer's eyes, and based on this, the controller adjusts the rotation angle of the backlight toroidal mirror T MR and also adjusts the brightness of the backlight light source accordingly, so that the eye box EB extends or contracts to the eye position, allowing the observer to continuously observe a clear and complete image.

[0078] The driving module drives the backlight toroidal mirror T MR , and the backlight toroidal mirror T MR rotates based on the angle set by the controller.

[0079] The present invention can be implemented in various other forms without departing from its spirit or main features. Therefore, the above-described embodiments are merely illustrative in all respects and should not be interpreted as being limiting. The scope of the present invention is defined by the claims and is not limited to the text of the specification. Furthermore, all modifications and changes within the scope of the claims are within the scope of the present invention. [Explanation of symbols]

[0080] BL Backlight source BL_im Backlight source virtual image BL_im1 Backlight source virtual image BL_im2 Backlight source virtual image BL_im3 Backlight source virtual image BL_im4 Backlight source virtual image BL_im5 Backlight source virtual image BL_im6 Backlight source virtual image BL_im7 Backlight source virtual image BL_im8 Backlight source virtual image BL_im9 Backlight source virtual image BL_im10 Backlight source virtual image BL_im11 Backlight source virtual image BL_im12 Backlight source virtual image BL_im13 Backlight source virtual image BL_im14 Backlight source virtual image BL_im15 Backlight source virtual image BL_re Backlight light source real image BL_re1 Backlight light source real image BL_re2 Backlight light source real image BL_re3 Backlight light source real image BL_re4 Backlight light source real image BL_re5 Backlight light source real image BL_re6 Backlight light source real image BL_re7 Backlight light source real image BL_re8 Backlight light source real image BL_re9 Backlight light source real image BL_re10 Backlight light source real image BL_re11 Backlight light source real image BL_re12 Backlight light source real image BL_re13 Backlight light source real image BL_re14 Backlight light source real image BL_re15 Backlight light source real image Bm_G Image beam Bm_BL Backlight Beam CA center axis DP display panel DP_im Image virtual image E eyes EB Eye Box fx focus Fy focus FL_x focal length FL_x1 equivalent focal length FL_x2 equivalent focal length FL_x3 equivalent focal length FL_x4 equivalent focal length FL_x5 equivalent focal length FL_y focal length FL_y1 equivalent focal length FL_y2 equivalent focal length FL_y3 Equivalent focal length FL_y4 Equivalent focal length FL_y5 Equivalent focal length FPX X-axis backlight focal plane FPY Y-axis backlight focal plane Lt_BL Backlight source Mr_BL Backlit Concave Mirror Mr_F Imaging concave mirror Mr_SR Imaging Half Mirror P point light source q1 position q2 position q3 Position q4 position q5 position q6 position q7 position q8 position q9 position q10 position q11 position TMr backlight toroidal mirror X-axis direction Y-axis direction θy angle θy1 angle θy2 angle θy3 angle θy4 angle θx5 angle θx6 angle

Claims

1. A head-up display that adjusts an eyebox with a backlit toroidal mirror adapted for use in combination with an imaging half mirror, a backlight source for projecting a backlight beam; a backlight toroidal mirror that is rotatable and has an X-axis curvature on an X-axis and a Y-axis curvature on a Y-axis, the X-axis curvature being different from the Y-axis curvature, the backlight toroidal mirror being used to reflect the backlight beam of the backlight light source; a display panel arranged to display an image and transmit the backlight beam reflected by the backlight toroidal mirror to form an image beam; an imaging concave mirror that is disposed so as to reflect the image beam onto the imaging half mirror, form a display panel virtual image at one side of the imaging half mirror that is remote from a viewer, and form a backlight light source real image at one side of the imaging half mirror that is close to the viewer and at the position of the viewer's eyes, the backlight light source real image being an eye box; a backlight toroidal mirror that adjusts an eyebox according to a first embodiment of the present invention; a backlight toroidal mirror that adjusts an eyebox according to a first embodiment of the present invention; a backlight toroidal mirror that adjusts an eyebox according to a first embodiment of the present invention; a backlight toroidal mirror that adjusts an eyebox according to a first embodiment of the present invention; a backlight toroidal mirror that adjusts an eyebox according to a first embodiment of the present invention;

2. 2. The head-up display according to claim 1, wherein the backlight toroidal mirror rotates around its central axis.

3. 2. The head-up display with eyebox adjustment using a backlight toroidal mirror according to claim 1, wherein an included angle in the Y-axis direction is formed between the optical axis of the backlight beam and the central axis of the backlight toroidal mirror, the backlight toroidal mirror rotates by a rotation angle with its central axis as a center of rotation, and the X-axis curvature of the surface of the backlight toroidal mirror on which the backlight beam is irradiated is smaller than the Y-axis curvature, the range of the eyebox extends as the rotation angle increases from 0 degrees to 90 degrees, and the range of the eyebox contracts as the rotation angle decreases from 90 degrees to 0 degrees.

4. 2. The head-up display with eyebox adjustment using a backlight toroidal mirror according to claim 1, wherein an included angle in the Y-axis direction is formed between the optical axis of the backlight beam and the central axis of the backlight toroidal mirror, the backlight toroidal mirror rotates by a rotation angle with its central axis as a center of rotation, and the X-axis curvature of the surface of the backlight toroidal mirror on which the backlight beam is irradiated is greater than the Y-axis curvature, the range of the eyebox shortens as the rotation angle increases from 0 degrees to 90 degrees, and the range of the eyebox expands as the rotation angle decreases from 90 degrees to 0 degrees.

5. 2. The head-up display with eyebox adjustment using a backlight toroidal mirror according to claim 1, wherein an included angle in the X-axis direction is formed between the optical axis of the backlight beam and the central axis of the backlight toroidal mirror, the backlight toroidal mirror rotates by a rotation angle with the central axis as a center of rotation, and the X-axis curvature of the surface of the backlight toroidal mirror on which the backlight beam is irradiated is smaller than the Y-axis curvature, the range of the eyebox shortens as the rotation angle increases from 0 degrees to 90 degrees, and the range of the eyebox expands as the rotation angle decreases from 90 degrees to 0 degrees.

6. 2. The head-up display with eyebox adjustment using a backlight toroidal mirror according to claim 1, wherein an included angle in the X-axis direction is formed between the optical axis of the backlight beam and the central axis of the backlight toroidal mirror, the backlight toroidal mirror rotates by a rotation angle with its central axis as a center of rotation, and the X-axis curvature of the surface of the backlight toroidal mirror on which the backlight beam is irradiated is greater than the Y-axis curvature, the range of the eyebox extends as the rotation angle increases from 0 degrees to 90 degrees, and the range of the eyebox contracts as the rotation angle decreases from 90 degrees to 0 degrees.

7. 2. The head-up display in which the eyebox is adjusted by the backlight toroidal mirror according to claim 1, wherein the brightness of the backlight light source is improved when the range of the eyebox is expanded by rotating the backlight toroidal mirror.

8. 2. A head-up display that adjusts an eyebox using a backlight toroidal mirror according to claim 1, wherein when the range of the eyebox is shortened by rotating the backlight toroidal mirror, the brightness of the backlight light source is reduced.

9. A head-up display for adjusting an eyebox with a backlit toroidal mirror as described in claim 1, characterized in that the imaging half mirror is a windshield or a combiner, and is used to partially reflect the image beam from the imaging concave mirror to the eye of the observer and at the same time partially transmit light rays of the scene in front of it to the eye of the observer.

Images