Computer generated hologram type display device

Patent metadata

Field	Value
Publication number	US-9244278-B2
Application number	US-201313858329-A
Country	US
Kind code	B2
Filing date	Apr 8, 2013
Priority date	Apr 10, 2012
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

A display device includes: a light source; an illumination optical system; a diffraction pattern generation unit; a spatial modulation element that generates diffracted light; and a shielding unit that selectively enters a first state where a first and second partial areas are a transmitting and shielding areas, respectively, and a second state where the first and second partial areas are the shielding and transmitting areas, respectively. The spatial modulation element displays the fictive image on a first and second display areas corresponding to the first and second partial areas when the shielding unit is in the first and second states, respectively. The diffraction pattern generation unit generates a first and second portion diffraction patterns from an image in an area corresponding to the first and second display areas out of the original image when the shielding unit is in the first and second states, respectively.

First claim

What is claimed is:

1. A display device, comprising:
a light source that outputs laser light;
an illumination optical system that emits the laser light as illumination light;
a processor that generates a diffraction pattern from an original image, the diffraction pattern being different from the original image and being calculated to appear to a user as a fictive image at a distance from the user;
a spatial modulation element that is illuminated by the illumination light, diffracts the illumination light by displaying the diffraction pattern to generate diffracted light directed to a location of eyes of the user to create the fictive image calculated to appear at the distance from the user; and
a shield that is disposed on an optical path of the diffracted light, and has a first partial area and a second partial area adjacent to the first partial area, wherein
the shield is configured so as to selectively enter one of a plurality of states including a first state where the first partial area is a transmitting area that transmits the diffracted light and where the second partial area is a shielding area that shields the diffracted light, and a second state where the first partial area is the shielding area and where the second partial area is the transmitting area,
the spatial modulation element displays the diffraction pattern being generated by the processor on a first display area corresponding to the first partial area when the shielding unit is in the first state, and displays the diffraction pattern being generated by the processor in a second display area corresponding to the second partial area when the shield is in the second state, and
the processor generates, as the diffraction pattern, a first portion diffraction pattern from an image in an area corresponding to the first display area of the original image when the shield is in the first state, and generates, as the diffraction pattern, a second portion diffraction pattern from an image in an area corresponding to the second display area of the original image when the shield is in the second state.

2. The display device according to claim 1 , wherein
the processor:
generates at least one type of correction pattern;
generates, as the diffraction pattern, a first portion composite diffraction pattern in which the generated correction pattern and the first portion diffraction pattern are combined; and
generates, as the diffraction pattern, a second portion composite diffraction pattern in which the generated correction pattern and the second portion diffraction pattern are combined.

3. The display device according to claim 2 , wherein the processor:
acquires visual acuity of the user; and
determines the distance from the eye of the user to the fictive image according to the visual acuity of the user.

4. The display device according to claim 3 , further comprising a storage device that stores information on the visual acuity of the user, wherein the processor acquires the information on the visual acuity of the user from the storage device and the information is used to determine the distance.

5. The display device according to claim 1 , wherein
the shield is disposed with respect to the spatial modulation element so that, out of the diffracted light, plus first-order diffracted light enters the first partial area and minus first-order diffracted light enters the second partial area.

6. The display device according to claim 5 , further comprising a reflecting mirror that reflects the diffracted light toward the user, wherein
the shield is disposed in a vicinity of an intermediate position between the spatial modulation element and the reflecting mirror.

7. The display device according to claim 5 , further comprising a collective optical system that collects the diffracted light, wherein
the shield is disposed in a vicinity of a collecting position of the diffracted light that is collected by the collective optical system.

8. The display device according to claim 1 , wherein
the shield includes a liquid crystal panel that is configured to be able to diffract incident light by forming interference fringes on a surface thereof, and is configured to be able to control presence or absence of the interference fringes by applying voltage.

9. The display device according to claim 1 , wherein
the illumination optical system includes a deflecting element that changes a direction of the illumination light with respect to the spatial modulation element,
the deflecting element is configured to be able to change the direction of the illumination light to a first direction in which the display area of the fictive image is a first setting area, and to a second direction in which the display area of the fictive image is a second setting area which is adjacent to the first setting area, and
the processor generates a first setting diffraction pattern from an image in an area corresponding to the first setting area out of the original image when the direction of the illumination light is the first direction, and generates a second setting diffraction pattern from an image in an area corresponding to the second setting area out of the original image when the direction of the illumination light is the second direction.

10. The display device according to claim 9 , wherein
the processor:
generates at least one type of correction pattern to correct the diffraction pattern;
generates a first setting composite diffraction pattern in which the generated correction pattern and the first setting diffraction pattern are combined; and
generates a second setting composite diffraction pattern in which the generated correction pattern and the second setting diffraction pattern are combined.

11. The display device according to claim 10 , wherein the processor:
acquires visual acuity of the user;
determines an optimum reconstruction position of the fictive image according to the visual acuity of the user; and
generates the correction pattern so that the fictive image is displayed at the optimum reconstruction position.

12. The display device according to claim 1 , wherein the processor:
judges a specific area out of the original image, and
generates a specific correction pattern for correcting the diffraction pattern based on the position of the specific area in the original image, and generates a specific composite diffraction pattern in which the generated specific correction pattern and the generated diffraction pattern are combined.

13. The display device according to claim 12 , wherein the processor:
acquires visual acuity of the user;
determines an optimum reconstruction position of the fictive image according to the visual acuity of the user; and
generates the specific correction pattern so that an area corresponding to the specific area, out of the fictive image, is displayed at the optimum reconstruction position.

14. The display device according to claim 13 , wherein the processor:
determines a specific position to generate the specific correction pattern so that the area corresponding to the specific area, out of the fictive image, is displayed at the optimum reconstruction position; and
generates the specific correction pattern from a phase in a case where a spherical wave from a point light source virtually disposed in the specific position enters the spatial modulation element.

15. The display device according to claim 12 , wherein the processor:
detects a line-of-sight position of the user; and
judges, as the specific area, an area of the original image corresponding to an area of the fictive image including the line-of-sight

Assignees

• Panasonic Corp
• Panasonic Ip Man Co Ltd

Inventors

• Sugiyama Keiji
• Kasazumi Kenichi

Classifications

• G02B27/017

  Head mounted · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B27/0103 Primary

  comprising holographic elements · CPC title

• G02B2027/011

  comprising device for correcting geometrical aberrations, distortion · CPC title

• G02B2027/014

  comprising information/image processing systems · CPC title