Image projection device, image projection screen and image display system

1. An image projector comprising a first light source that emits visible light and a second light source that emits invisible light and projecting the visible light and the invisible light onto a screen,

wherein the screen includes a material, at least one of the visible light reflectance, transmittance and absorbance of which changes when irradiated with the invisible light projected, and

wherein the image projector further includes:

a modulating section for modulating the intensities of the visible light and invisible light based on an image signal; and

a control section for controlling the modulating section, and

wherein the control section includes a visible light source control section and an invisible light source control section, and

wherein the invisible light source control section includes a correcting section for correcting an inverted luminance signal, which is obtained by inverting a luminance signal associated with the image signal, and

wherein the correcting section makes at least one correction selected from the group consisting of: a correction to the luminance level of the inverted luminance signal; the correction of truncating portions of the inverted luminance signal that have a predetermined luminance level or less; and the correction of truncating portions of the inverted luminance signal that have predetermined intermediate luminance levels.

2. The image projector of claim 1 , wherein the modulating section modulates the intensity of the invisible light based on a luminance signal associated with the image signal.

3. The image projector of claim 2 , wherein the image signal is RGB signals, and

wherein the control section converts the RGB signals into the luminance signal.

4. The image projector of claim 1 , further comprising at least one of an illuminance detecting section for detecting an illuminance at an image projection area and a temperature detecting section for detecting a temperature at the image projection area,

wherein the correcting section corrects the inverted luminance signal based on at least one of the illuminance and temperature at the image projection area.

5. The image projector of claim 1 , further comprising at least one of an illuminance detecting section for detecting an illuminance at an image projection area and a temperature detecting section for detecting a temperature at the image projection area,

wherein the control section adjusts at least one of the energy and duration of the projected invisible light based on at least one of the illuminance and temperature at the image projection area.

6. The image projector of claim 1 , further comprising:

a scanning section with a reflective plane for reflecting and projecting the visible light and invisible light that have been emitted from the first and second light sources; and

a driving section for driving the scanning section.

7. The image projector of claim 1 , wherein the material included in the screen is a photochromic compound.

8. The image projector of claim 7 , wherein the photochromic compound includes a transparent material.

9. The image projector of claim 7 , wherein the photochromic compound includes an opaque material.

10. The image projector of claim 1 , wherein at least one of the reflectance, transmittance and absorbance of the screen varies with the energy of the invisible light projected.

11. The image projector of claim 1 , wherein at least one of the reflectance, transmittance and absorbance of the screen varies with the duration of the invisible light projected.

12. The image projector of claim 1 , wherein the screen includes the material on the projection side thereof and/or its reverse side.

13. An image display system comprising the image projector of claim 1 and the screen.