Head-up display apparatus, screen member, manufacturing method thereof and image projecting method

• US 8,675,283 B2
• Filed: 08/24/2012
• Issued: 03/18/2014
• Est. Priority Date: 08/29/2011
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Fujikawa, Takayuki, Ando, Hiroshi
• Primary Examiner(s): Martinez, Joseph P
• Application Number:
  US13/593,615
• Publication Number:
  US 20130050655A1
• Time in Patent Office: 571 Days
• Field of Search: 359/630, 359/563, 353/28
• US Class Current: 359/630
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0145 creating an intermediate image
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements

Abstract

A screen member diffuses a bundle of rays of light projected from a laser scanner such that the bundle of rays of light is guided to a viewing range. The screen member includes a plurality of optical elements. A surface of each optical element forms a curved surface that diffuses the bundle of rays of light, which enters the curved surface. The optical elements are arranged in a lattice pattern at each corresponding pitch that is set to adjust a peak-to-peak interval of diffracted rays, which are formed in the viewing range by diffraction of the bundles of rays diffused by the plurality of optical elements, to a value that is equal to or smaller than a diameter of a pupil of the viewer.

Claims

1. A head-up display apparatus that is configured to project a display image onto a projection surface of a vehicle and thereby to enable a viewer located in a vehicle cabin of the vehicle to view a virtual image of the display image, the head-up display apparatus comprising:

a projector that is configured to project a bundle of rays of light, which forms the display image; and

a screen member that diffuses the bundle of rays of light such that the bundle of rays of light is guided to a viewing range, in which the virtual image is visually recognizable by the viewer in the vehicle cabin, wherein;

the screen member includes a plurality of optical elements;

a surface of each of the plurality of optical elements forms a curved surface that diffuses the bundle of rays of light, which enters the curved surface; and

the plurality of optical elements is arranged continuously one after another in two or more directions at each corresponding pitch that is set to adjust a peak-to-peak interval of diffracted rays, which are formed in the viewing range by diffraction of the bundles of rays diffused by the plurality of optical elements, to a value that is equal to or smaller than 8 mm.

2. The head-up display apparatus according to claim 1, wherein the plurality of optical elements is arranged continuously one after another in the two or more directions at each corresponding pitch that is set to adjust the peak-to-peak interval of the diffracted rays to the value that is equal to or smaller than 2 mm.

3. The head-up display apparatus according to claim 1, wherein:

the bundles of rays of light are diffused by the plurality of optical elements, respectively, to form a plurality of virtual image points, respectively, which form the virtual image;

each corresponding pitch of the plurality of optical elements is set to adjust each corresponding pitch of the plurality of virtual image points to a value that is equal to or smaller than a resolution of an eye of the viewer; and

the resolution of the eye of the viewer is a visual angle of 1/60 degrees that is set as an angle of a gap of a Landolt ring.

4. The head-up display apparatus according to claim 3, further comprising an optical system, which is placed in an optical path between the screen member and the projection surface formed in a display member of the vehicle, wherein:

the bundles of rays of light diffused by the plurality of optical elements, respectively, are guided along the optical path;

the optical system is configured to enlarge the bundles of rays of light, which are diffused by the plurality of optical elements, respectively; and

each corresponding pitch of the plurality of virtual image points is enlarged by the optical system alone or in cooperation with the display member relative to each corresponding pitch of the plurality of optical elements by a corresponding magnification power that is in a range of 4 to 8 times.

5. The head-up display apparatus according to claim 1, wherein each pitch of the plurality of optical elements is set in a range of 50 to 200 μ

m.

6. The head-up display apparatus according to claim 1, wherein:

the viewing range, in which the virtual image is visually recognizable by two eyes of the viewer, is configured into a shape of quadrangle that is defined by four outer edges;

two of the four outer edges of the viewing range are generally parallel to each other and are opposed to each other in a first opposing direction of the viewing range, which generally coincides with a left-to-right-direction of the vehicle, and the other two of the four outer edges of the viewing range are generally parallel to each other and are opposed to each other in a second opposing direction of the viewing range, which is perpendicular to the first opposing direction of the viewing range and generally coincides with a top-to-bottom direction of the vehicle; and

the viewing range has a first length in a range of 80 to 200 mm in the first opposing direction of the viewing range and a second length in a range of 30 to 200 mm in the second opposing direction of the viewing range.

7. The head-up display apparatus according to claim 6, wherein:

each of the plurality of optical elements diffuses the bundle of rays of light such that a first angle of diffusion of the bundle of rays of light, which is diffused by the optical element over the viewing range throughout the first length of the viewing range measured in the first opposing direction of the viewing range, is in a range of 10 to 50 degrees, and a second angle of diffusion of the bundle of rays of light, which is diffused by the optical element over the viewing range throughout the second length of the viewing range measured in the second opposing direction of the viewing range, is in a range of 5 to 50 degrees;

each of the plurality of optical elements is configured into a shape of quadrangle, which is generally homothetic to the shape of quadrangle of the viewing range and is defined by four outer edges;

two of the four outer edges of each optical element, which correspond to the two of the four outer edges of the viewing range, are generally parallel to each other and are opposed to each other in a first opposing direction of the optical element, and the other two of the four outer edges of the optical element, which correspond to the other two of the four outer edges of the viewing range, are generally parallel to each other and are opposed to each other in a second opposing direction of the optical element, which is perpendicular to the first opposing direction of the optical element;

a first radius of curvature of an arc of the curved surface of each of the plurality of optical elements, which is arcuately curved in the first opposing direction of the optical element, is in a range of 0.1 to 2 mm; and

a second radius of curvature of an arc of the curved surface of each of the plurality of optical elements, which is arcuately curved in the second opposing direction of the optical element, is in a range of 0.1 to 2 mm.

8. The head-up display apparatus according to claim 1, wherein:

the projector is configured to project a plurality of colors of single-wavelength laser lights, each of which has a corresponding peak wavelength, as the bundle of rays of light; and

a maximum wavelength among the corresponding peak wavelengths of the plurality of colors of single-wavelength laser lights is in a range of 600 to 650 nm.

9. A head-up display apparatus that is configured to project a display image onto a projection surface of a vehicle and thereby to enable a viewer located in a vehicle cabin of the vehicle to view a virtual image of the display image, the head-up display apparatus comprising:

a projector that is configured to project a bundle of rays of light, which forms the display image; and

a screen member that diffuses the bundle of rays of light such that the bundle of rays of light is guided to a viewing range, in which the virtual image is visually recognizable by the viewer in the vehicle cabin, wherein;

the screen member includes a plurality of optical elements;

a surface of each of the plurality of optical elements forms a curved surface that diffuses the bundle of rays of light, which enters the curved surface; and

the plurality of optical elements is arranged continuously one after another in two or more directions at each corresponding pitch that is set to adjust a peak-to-peak interval of diffracted rays, which are formed in the viewing range by diffraction of the bundles of rays diffused by the plurality of optical elements, to a value that is equal to or smaller than a diameter of a pupil of the viewer.

10. The head-up display apparatus according to claim 9, wherein:

the viewing range is configured into a shape of polygon, which is defined by a plurality of outer edges;

each of the plurality of optical elements is configured into a shape of polygon, which is generally homothetic to the shape of polygon of the viewing range and is defined by a plurality of outer edges;

each of the polygon of the viewing range and the polygon of each of the plurality of optical elements is configured such that a total number of the plurality of outer edges of the polygon is defined by 2N where N is an integer number that is equal to or larger than 2, and a total number of a plurality of opposing directions, in each of which corresponding parallel two of the plurality of outer edges of the polygon are opposed to each other, is N; and

the corresponding pitch of the plurality of optical elements in each corresponding one of the plurality of opposing directions satisfies the following equation;

11. The head-up display apparatus according to claim 10, wherein:

the projector is configured to project a plurality of colors of single-wavelength laser lights, each of which has a peak wavelength, as the bundle of rays of light; and

the wavelength of λ

is a maximum wavelength among the peak wavelengths of the plurality of colors of single-wavelength laser lights.

12. The head-up display apparatus according to claim 9, wherein:

the bundles of rays of light are diffused by the plurality of optical elements, respectively, to form a plurality of virtual image points, respectively, which form the virtual image; and

each corresponding pitch of the plurality of optical elements is set to adjust each corresponding pitch of the plurality of virtual image points to a value that is equal to or smaller than a resolution of an eye of the viewer.

13. The head-up display apparatus according to claim 12, further comprising an optical system, which is placed in an optical path between the screen member and the projection surface of the vehicle, wherein:

the bundles of rays of light diffused by the plurality of optical elements, respectively, are guided along the optical path;

the optical system is configured to enlarge the bundles of rays of light, which are diffused by the plurality of optical elements, respectively; and

each corresponding pitch of the plurality of virtual image points is enlarged by the optical system relative to each corresponding pitch of the plurality of optical elements.

14. The head-up display apparatus according to claim 13, wherein:

each of the plurality of optical elements is configured into a shape of polygon that is defined by a plurality of outer edges;

a total number of the plurality of outer edges of the polygon of each optical element is defined by 2N where N is an integer number that is equal to or larger than 2, and a total number of a plurality of opposing directions, in each of which corresponding parallel two of the plurality of outer edges of the polygon are opposed to each other, is N;

the optical system is placed in the optical path between the screen member and the projection surface formed in a display member of the vehicle; and

the corresponding pitch of the plurality of optical elements in each corresponding one of the plurality of opposing directions satisfies the following equation;

15. The head-up display apparatus according to claim 10, wherein:

the polygon of each of the plurality of optical elements is a square; and

all of the corresponding pitches of the plurality of optical elements in the plurality of opposing directions, respectively, are generally equal to each other.

16. The head-up display apparatus according to claim 9, wherein a radius of curvature of each corresponding arc of the curved surface of each of the plurality of optical elements is set based on a corresponding angle of diffusion of the bundle of rays of light, which is diffused by the curved surface of the optical element over the viewing range throughout the viewing range.

17. The head-up display apparatus according to claim 16, wherein:

the viewing range is configured into a shape of polygon that is defined by a plurality of outer edges;

each of the plurality of optical elements is configured into a shape of polygon that is generally homothetic to the shape of polygon of the viewing range and is defined by a plurality of outer edges;

each of the polygon of the viewing range and the polygon of each of the plurality of optical elements is configured such that a total number of the plurality of outer edges of the polygon is defined by 2N where N is an integer number that is equal to or larger than 2, and a total number of a plurality of opposing directions, in each of which corresponding parallel two of the plurality of outer edges are opposed to each other, is N; and

the corresponding radius of curvature of the corresponding arc of the curved surface of each of the plurality of optical elements, which is arcuately curved in the corresponding one of the plurality of opposing directions, satisfies the following equation;

18. The head-up display apparatus according to claim 9, wherein:

the viewing range is configured into a shape of quadrangle that is defined by four outer edges;

two of the four outer edges of the viewing range are generally parallel to each other and are opposed to each other in a first opposing direction of the viewing range, which generally coincides with a left-to-right direction of the vehicle, and the other two of the four outer edges of the viewing range are generally parallel to each other and are opposed to each other in a second opposing direction of the viewing range, which generally coincides with a top-to-bottom direction of the vehicle; and

the viewing range has a first length in the first opposing direction of the viewing range, and a second length in the second opposing direction of the viewing range.

19. The head-up display apparatus according to claim 18, wherein the quadrangle of the viewing range is an elongated rectangle, and the first length of the viewing range is larger than the second length of the viewing range.

20. A head-up display apparatus that is configured to project a display image onto a projection surface formed in a display member of a vehicle and thereby to enable a viewer located in a vehicle cabin of the vehicle to view a virtual image of the display image, the head-up display apparatus comprising:

a projector that is configured to project a bundle of rays of light, which forms the display image; and

a screen member that diffuses the bundle of rays of light such that the bundle of rays of light is guided to a viewing range, in which the virtual image is visually recognizable by the viewer in the vehicle cabin, wherein;

the viewing range is configured into a shape of quadrangle that is defined by four outer edges;

two of the four outer edges of the viewing range are generally parallel to each other and are opposed to each other in a first opposing direction of the viewing range, which generally coincides with a left-to-right-direction of the vehicle, and the other two of the four outer edges of the viewing range are generally parallel to each other and are opposed to each other in a second opposing direction of the viewing range, which is perpendicular to the first opposing direction of the viewing range and generally coincides with a top-to-bottom direction of the vehicle;

the screen member includes a plurality of optical elements, each of which is configured into a shape of quadrangle that is generally homothetic to the shape of quadrangle of the viewing range and is defined by four outer edges;

two of the four outer edges of each optical element, which correspond to the two of the four outer edges of the viewing range, are generally parallel to each other and are opposed to each other in a first opposing direction of the optical element, and the other two of the four outer edges of the optical element, which correspond to the other two of the four outer edges of the viewing range, are generally parallel to each other and are opposed to each other in a second opposing direction of the optical element, which is perpendicular to the first opposing direction of the optical element;

a surface of each of the plurality of optical elements forms a curved surface that diffuses the bundle of rays of light, which enters the curved surface, toward the viewing range;

the plurality of optical elements is arranged continuously one after another at a first pitch in the first opposing direction of each optical element and a second pitch in the second opposing direction of each optical element;

the first pitch satisfies the following equation;

21. The head-up display apparatus according to claim 20, further comprising an optical system, which is placed in an optical path between the screen member and the projection surface of the display member, wherein:

the bundles of rays of light diffused by the plurality of optical elements, respectively, are guided along the optical path;

the optical system is configured to enlarge the bundles of rays of light, which are diffused by the plurality of optical elements, respectively;

the first pitch satisfies the following equation;

22. The head-up display apparatus according to claim 20, wherein:

a first radius of curvature of an arc of the curved surface of each of the plurality of optical elements, which is arcuately curved in the first opposing direction, satisfies the following equation;

23. The head-up display apparatus according to claim 20, wherein the projector is configured to project a laser light as the bundle of rays of light.

24. The head-up display apparatus according to claim 20, wherein each of the plurality of optical elements is configured to reflect the bundle of rays of light, which is projected from the projector, to diffuse the bundle of rays of light.

25. The head-up display apparatus according to claim 20, wherein each of the plurality of optical elements is configured to transmit the bundle of rays of light, which is projected from the projector, through the optical element to diffuse the bundle of rays of light.

26. A screen member for a head-up display apparatus that is configured to project a display image onto a projection surface of a vehicle and thereby to enable a viewer located in a vehicle cabin of the vehicle to view a virtual image of the display image upon diffusing a bundle of rays of light, which is projected from a projector, by the screen member to guide the bundle of rays of light to a viewing range, in which the virtual image is visually recognizable by the viewer in the vehicle cabin, the screen member comprising:

a plurality of optical elements, wherein;

a surface of each of the plurality of optical elements forms a curved surface that diffuses the bundle of rays of light, which enters the curved surface; and

the plurality of optical elements is arranged continuously one after another in two or more directions at each corresponding pitch that is set to adjust a peak-to-peak interval of diffracted rays, which are formed in the viewing range by diffraction of the bundles of rays diffused by the plurality of optical elements, to a value that is equal to or smaller than a diameter of a pupil of the viewer.

27. A manufacturing method of a screen member for a head-up display apparatus that is configured to project a display image onto a projection surface of a vehicle and thereby to enable a viewer located in a vehicle cabin of the vehicle to view a virtual image of the display image upon diffusing a bundle of rays of light, which is projected from a projector, by the screen member to guide the bundle of rays of light to a viewing range, in which the virtual image is visually recognizable by the viewer in the vehicle cabin, the manufacturing method comprising:

determining each corresponding pitch of a plurality of optical elements of the screen member arranged continuously one after another in two or more directions to set a peak-to-peak interval of diffracted rays, which are formed in the viewing range upon occurrence of diffraction of bundles of rays diffused by the plurality of optical elements, to a value that is equal to or smaller than 8 mm; and

forming the screen member that has the plurality of optical elements, which are arranged continuously one after another in the two or more directions at each corresponding pitch that is determined in the determining of each corresponding pitch of the plurality of optical elements.

28. The manufacturing method according to claim 27, wherein the determining of each corresponding pitch of the plurality of optical elements includes determining each corresponding pitch of the plurality of optical elements such that each corresponding pitch of the plurality of optical elements satisfies the following equation:

29. The manufacturing method according to claim 27, wherein the determining of each corresponding pitch of the plurality of optical elements includes determining each corresponding pitch of the plurality of optical elements such that each corresponding pitch of the plurality of optical elements satisfies the following equation:

30. The manufacturing method according to claim 27, further comprising determining a corresponding radius of curvature of each corresponding arc of a curved surface of each of the plurality of optical elements before the forming of the screen member such that the corresponding radius of curvature of each corresponding arc of the curved surface of each of the plurality of optical elements satisfies:

31. An image projecting method of projecting a display image onto a projection surface of a vehicle to enable a viewer located in a vehicle cabin of the vehicle to view a virtual image of the display image, the image projecting method comprising:

adjusting a peak-to-peak interval of diffracted rays, which are formed in the viewing range, to a value that is equal to or smaller than a diameter of a pupil of the viewer through use of;

a projector that is configured to project a bundle of rays of light, which forms the display image; and

a screen member that diffuses the bundle of rays of light such that the bundle of rays of light is guided to the viewing range, in which the virtual image is visually recognizable by the viewer in the vehicle cabin, wherein;

the screen member includes a plurality of optical elements;

a surface of each of the plurality of optical elements forms a curved surface that diffuses the bundle of rays of light, which enters the curved surface, and the diffracted rays are formed in the viewing range by diffraction of the bundles of rays of light, which are diffused by the plurality of optical elements, respectively; and

the plurality of optical elements is arranged continuously one after another in two or more directions at each corresponding pitch.