Spatial image projection apparatus

Patent metadata

Field	Value
Publication number	US-2016100142-A1
Application number	US-201514876486-A
Country	US
Kind code	A1
Filing date	Oct 6, 2015
Priority date	Oct 6, 2014
Publication date	Apr 7, 2016
Grant date	—

Abstract

A spatial image projection apparatus including a receiver configured to receive an image signal; a display unit configured to display an image acquired by processing the image signal; a projection unit configured to project a spatial image to a prescribed space by transmitting or reflecting light corresponding to the image displayed on the display unit; and an optical-path length-converter located between the display unit and the projection unit so as to change an optical-path length of the image. Further, the optical-path length-converter includes a polarizer configured to transmit only specific polarized light, among the light introduced from the display unit, toward the projection unit, and to reflect the remaining light other than the specific polarized light; and a mirror configured to transmit light, introduced from the display unit, to the polarizer, and to convert the light reflected from the polarizer into specific polarized light so as to again reflect the light to the polarizer.

First claim

What is claimed is:

1 . A spatial image projection apparatus, comprising:
a receiver configured to receive an image signal; a display unit configured to display an image acquired by processing the image signal; a projection unit configured to project a spatial image to a prescribed space by transmitting or reflecting light corresponding to the image displayed on the display unit; and an optical-path length-converter located between the display unit and the projection unit so as to change an optical-path length of the image, wherein the optical-path length-converter includes: a polarizer configured to transmit only specific polarized light, among the light introduced from the display unit, toward the projection unit, and to reflect the remaining light other than the specific polarized light; and a mirror configured to transmit light, introduced from the display unit, to the polarizer, and to convert the light reflected from the polarizer into specific polarized light so as to again reflect the light to the polarizer.

2 . The apparatus according to claim 1 , wherein the polarizer includes a reflective polarizing plate configured to transmit only linearly polarized light.

3 . The apparatus according to claim 1 , wherein the mirror includes a one-way mirror configured to transmit light only in a given direction.

4 . The apparatus according to claim 1 , wherein the polarizer and the mirror are spaced apart from each other by a given distance.

5 . The apparatus according to claim 1 , wherein the polarizer is spaced apart from the display unit by a first distance,
wherein the mirror is spaced apart from the display unit by a second distance, and wherein the first distance is longer than the second distance.

6 . The apparatus according to claim 1 , wherein the polarizer and the mirror have the same area.

7 . The apparatus according to claim 1 , wherein at least one of the polarizer and the mirror has the same area as an area of the display unit.

8 . The apparatus according to claim 1 , wherein the optical-path length-converter is configured to change an optical-path length from the display unit to the projection unit to the sum of a first optical-path length from the display unit to the polarizer, a second optical-path length from the polarizer to the mirror, and a third optical-path length from the mirror to the projection unit.

9 . The apparatus according to claim 8 , wherein the first optical-path length is a distance between a light emission surface of the display unit and a light reflection surface of the polarizer,
wherein the second optical-path length is a distance between the light reflection surface of the polarizer and a light reflection surface of the mirror, and wherein the third optical-path length is a distance between the light reflection surface of the mirror and a light introduction surface of the projection unit.

10 . The apparatus according to claim 8 , wherein the sum of the first, second, and third optical-path lengths is changed according to a distance between the display unit and the projection unit.

11 . The apparatus according to claim 10 , wherein the sum of the first, second, and third optical-path lengths increases as the distance between the display unit and the projection unit decreases, and decreases as the distance between the display unit and the projection unit increases.

12 . The apparatus according to claim 1 , wherein the optical-path length-converter changes the optical-path length by linearly moving at least one of the mirror and the polarizer toward the display unit or the projection unit in response to a control signal from the controller.

13 . The apparatus according to claim 12 , wherein, when optical-path length-converter linearly moves at least one of the mirror and the polarizer, at least one of the display unit and the projection unit is linearly moved toward the optical-path length-converter in response to a control signal from the controller.

14 . The apparatus according to claim 1 , wherein the optical-path length-converter includes:
a first wavelength plate located between the display unit and the mirror; and a second wavelength plate located between the mirror and the polarizer.

15 . The apparatus according to claim 14 , wherein the first and second wavelength plates are ¼λ wavelength plates.

16 . The apparatus according to claim 14 , wherein the first wavelength plate and the second wavelength plate have the same area.

17 . The apparatus according to claim 14 , wherein the area of the first and second wavelength plates is the same as an area of the display unit.

18 . The apparatus according to claim 1 , wherein the display unit is configured to polarize and emit light in a given direction when emitting the light corresponding to the image.

19 . The apparatus according to claim 1 , wherein the projection unit includes a single convex lens, or an array including a plurality of convex lenses.

20 . The apparatus according to claim 1 , wherein the projection unit includes:
a first lens configured to transmit light introduced from the optical-path length-converter so as to project a first spatial image to a first space; and a second lens spaced apart from the first lens by a given distance, the second lens being configured to reflect the light directed from the first lens so as to project a second spatial image to a second space.

Assignees

• Lg Electronics Inc
• Univ Kwangwoon Ind Acad Collab

Inventors

• Shin Sungchul
• Kim Eunsoo
• Kim Seungcheol

Classifications

• G02B30/56

  by projecting aerial or floating images · CPC title

• H04N9/3167 Primary

  for polarizing the light beam (polarizing optical systems per se G02B27/28) · CPC title

• H04N13/368

  for two or more viewers · CPC title

• G02B30/25

  using polarisation techniques · CPC title

• H04N13/393

  the volume being generated by a moving, e.g. vibrating or rotating, surface · CPC title