Projection display system with two reflecting mirrors

1. A projection display system comprising a projection display unit and a windable screen, the projection display unit projecting an image light onto a projection plane of the screen which is unwound to display an image;

wherein the projection display unit includes:

a light source;

an image display element;

a lighting optical system irradiating a beam of light from the light source on the image display element; and

a projection optical system projecting the image light from the image display element toward the screen, the projection optical system including, in order toward the screen from the image display element;

a front lens group composed of a plurality of lens elements being symmetrical with respect to an optical axis;

a rear lens group including an eccentric lens element with respect to the optical axis; and

a first reflecting mirror shaped to be axial-asymmetrical with respect to the optical axis and a second reflecting mirror;

wherein the image display element has a display, a center of the display being positioned on the optical axis, and a normal line of the display is inclined slightly with respect to the optical axis,

wherein the screen is provided with a case for accommodating the wound screen therein;

wherein the projection display unit is mechanically jointed to the screen so that the projection display unit is positioned in an imaginary plane substantially perpendicular to the display plane of the screen when the screen is taken out from the case and unwound; and

wherein the first reflecting mirror is located within a unit housing, and the second reflecting mirror is planar mirror and is fixed rotatably to a part of the unit housing such that the second mirror is fixed at a predetermined degree in use, so that a distance between the unit housing and the display plane of the screen is shortened by replicating the image light.

2. The system according to claim 1 , wherein the projection display unit is integrated with the case so that one side face of the projection display unit is fixed to the case at a substantially center portion in an elongated direction of the case.

3. The system according to claim 2 , wherein the projection display unit is designed to be fixed on a ceiling.

4. The system according to claim 2 , wherein the screen is provided with a handle.

5. The system according to claim 1 , wherein the projection display unit has one side face and the one side face is detachably connected to the case at a substantially center portion in an elongated direction of the case.

6. The system according to claim 1 , wherein a pair of projection display units are arranged close to upper and lower or left and right sides of the screen and along a pair of imaginary plane extended from the upper and lower or left and right sides in a direction substantially perpendicular to the projection plane;

wherein an image light from the image display element is reflected and widened by a reflecting surface of the reflecting mirror and outgoes from the projection display unit; and

wherein the pair of projection display units arranged on the upper and lower or left and right sides of the screen project same or mutually different images on the screen so that the images are composed whereby a large screen display is enabled.

7. The system according to claim 1 , wherein a plurality of projection display units and a plurality of screens are provided, the plurality of screens surround a booth where an operator is positioned, wherein each projection display unit projects a corresponding image on corresponding screen so that three-dimensional pseudo image is presented to the operator.

8. The system according to claim 7 , wherein a dynamic image is projected from the projection display units on the screens.

9. The system according to claim 7 , wherein each projection display unit is arranged above and substantially centrally of corresponding screen.

10. A projection display system comprising a projection display unit and a white board, the projection display unit projecting an image light onto a projection plane of the white board to display an image;

wherein the projection display unit includes:

a light source;

an image display element;

a lighting optical system irradiating a beam of light from the light source on the image display element; and

a projection optical system projecting the image light from the image display element toward the screen, the projection optical system including, in order toward the screen from the image display element;

a front lens group composed of a plurality of lens elements being symmetrical with respect to an optical axis;

a rear lens group including an eccentric lens element with respect to the optical axis; and

a first reflecting mirror shaped to be axial-asymmetrical with respect to the optical axis and a second reflecting mirror;

wherein the image display element has a display, a center of the display being positioned on the optical axis, and a normal line of the display is inclined slightly with respect to the optical axis;

wherein the white board includes a frame and a surface, and the projection display unit is integrated with a part of the frame so as to project a projection image on the surface of the white board; and

wherein the first reflecting mirror is located within a unit housing, and the second reflecting mirror is planar mirror and is fixed rotatably to a part of the unit housing such that the second mirror is fixed at a predetermined degree in use, so that a distance between the unit housing and the display plane of the screen is shortened by replicating the image light.

11. The system according to claim 10 , wherein the projection display unit is arranged substantially centrally of an upper side of the frame of the white board.

12. The system according to claim 11 , wherein the projection display unit is arranged so as to project a projection image to a lower projection plane.

13. The system according to claim 12 , wherein the projection display unit is arranged so as to project a projection image to a lower projection plane through a mirror.

14. A projection display system comprising a projection display unit, a notice board, and a pedestal for building the notice board thereon, the projection display unit projecting an image light onto a projection plane of the notice board to display an image;

wherein the projection display unit includes:

a light source;

an image display element;

a lighting optical system irradiating a beam of light from the light source on the image display element; and

a projection optical system projecting the image light from the image display element toward the screen, the projection optical system including, in order toward the screen from the image display element;

a front lens group composed of a plurality of lens elements being symmetrical with respect to an optical axis;

a rear lens group including an eccentric lens element with respect to the optical axis; and

a first reflecting mirror shaped to be axial-asymmetrical with respect to the optical axis and a second reflecting mirror;

wherein the image display element has a display, a center of the display being positioned on the optical axis, and a normal line of the display is inclined slightly with respect to the optical axis;

wherein the projection display unit is incorporated in the pedestal; and

wherein the first reflecting mirror is located within a unit housing, and the second reflecting mirror is planar mirror and is fixed rotatably to a part of the unit housing such that the second mirror is fixed at a predetermined degree in use, so that a distance between the unit housing and the display plane of the screen is shortened by replicating the image light.

15. The system according to claim 14 , wherein the projection display unit projects at least one of a still image and a dynamic image on the notice board.

16. The system according to claim 14 , wherein a plurality of pedestals and projection display units are provided, each pedestal incorporating corresponding projection display unit, and wherein the plurality of pedestals are aligned laterally.

17. The system according to claim 14 , wherein a plurality of display projection units are provided whereby different images are projected on the notice board.

18. The system according to claim 1 , wherein the second reflecting mirror is designed such way that the reflecting mirror can be opened or closed by an opening mechanism.

19. The system according to claim 10 , wherein the second reflecting mirror is designed such way that the reflecting mirror can be opened or closed by an opening mechanism.

20. The system according to claim 14 , wherein the second reflecting mirror is designed such way that the reflecting mirror can be opened or closed by an opening mechanism.

21. The system according to claim 1 , wherein the first reflecting mirror has a free-form surface.

22. The system according to claim 10 , wherein the first reflecting mirror has a free-form surface.

23. The system according to claim 14 , wherein the first reflecting mirror has a free-form surface.