SCANNING PROJECTION APPARATUS AND SCANNING IMAGE DISPLAY
In a light beam scanning projection apparatus which scans a light beam emitted from a laser light source, an image display apparatus is configured including a plurality of light beams, a reflection mirror for reflecting the light beams to project them onto a screen or the like, and a mirror driving unit for driving the reflection mirror so that the plurality of light beams are incident on the reflection mirror with different optical axes and projected on different projection areas, thereby displaying a single image with a plurality of images. Further, by forming a single image by causing a plurality of the light beams to have predetermined relative angles thereamong so as to make a plurality of images overlap on each other with slight shifts, a scanning projection apparatus is provided with which the luminance of the image is improved while conforming to safety standards.
1 . A scanning projection apparatus comprising:
a plurality of laser light sources;
optical means each of which converts an light beam emitted from each of the plurality of laser light sources into a substantially collimated light beam or a weakly converged light beam;
optical means which makes coincident with each other optical axes of the plurality of optical beams each converted into a substantially collimated light beam or a weakly converged light beam; and
an optical reflection and scan means which drives repetitive scan of the light beams of which optical axes are made coincident in directions of two axes substantially perpendicular to each other,
the scanning projection apparatus containing at least two or more light beams of which optical axes are made coincident and displaying a plurality of images on a projection screen by making the light beams of which optical axes are made coincident have predetermined relative angles therebetween so that the plurality of images are displayed with slight shifts of positions from each other.
2 . The scanning projection apparatus according to claim 1 , wherein the relative angles between the plurality of light beams which are emitted from the plurality of light sources and of which optical axes are made coincident are 4° or more.
3 . The scanning projection apparatus according to claim 1 , wherein a separation amount of the images in the plurality of images arranged with the shifts of positions from each other is ½ or less of a size of a image.
4 . The scanning projection apparatus according to claim 1 , wherein the plurality of light beams which are emitted from the plurality of light sources and of which optical axes are made coincident are substantially coincident with each other at a reflection area of the optical reflection and scan means which drives repetitive scan of the light beams of which optical axes are made coincident in directions of two axes substantially perpendicular to each other.
5 . The scanning projection apparatus according to claim 1 further comprising an optical element from which a plurality of light beams each made coincident with each other the optical axes of the light beams emitted from the plurality of light sources exit at predetermined angles, wherein surfaces from which the plurality of beams exit form a convex shapes with each other.
6 . The scanning projection apparatus according to claim 1 further comprising an optical element from which a plurality of light beams each made coincident with each other the optical axes of the light beams emitted from the plurality of light sources exit at predetermined angles, wherein surfaces from which the plurality of beams exit form a concave shape with each other.
7 . The scanning projection apparatus according to claim 1 further comprising an optical element from which a plurality of light beams each made coincident with each other the optical axes of the light beams emitted from the plurality of light sources exit at predetermined angles, wherein surfaces from which the plurality of beams exit form a concave shape with each other, and surfaces which the plurality of beams enter form a convex shape with each other.
8 . The scanning projection apparatus according to claim 1 further comprising an optical element from which a plurality of light beams each made coincident with each other the optical axes of the light beams emitted from the plurality of light sources exit at predetermined angles, wherein the optical element let the plurality of light beams exit at the predetermined angles by reflecting light beams entering the element a plurality of times.
9 . The scanning projection apparatus according to claim 8 , wherein in the optical element from which the plurality of light beams each made coincident with each other the optical axes of the light beams emitted from the plurality of light sources exit at predetermined angles light beams entering the optical element are incident perpendicular with respect to an incident end surface.
10 . The scanning projection apparatus according to claim 8 , wherein in the optical element from which the plurality of light beams each made coincident with each other the optical axes of the light beams emitted from the plurality of light sources exit at predetermined angles, light beams exiting from the optical element exit perpendicular with respect to an exit end surface.
11 . The canning projection apparatus according to claim 8 , wherein in the optical element from which the plurality of light beams each made coincident with each other the optical axes of the light beams emitted from the plurality of light sources exit at predetermined angles, at least one of reflection surfaces of the optical element lets part of the incident light beams transmit therethrough.
12 . A scanning image display with a scanning projection apparatus, comprising:
the scanning projection apparatus according to claim 1 ;
a laser light source driving circuit which drives the plurality of laser light sources;
a scan mirror driving circuit which supplies a driving signal to a scan mirror of the optical reflection and scan means so as to repetitively rotate the mirror surface two-dimensionally; and
a video signal processing circuit which transmits respective RGB signals to the laser light source driving circuit and the scan mirror driving circuit.
13 . The scanning projection apparatus according to claim 1 , wherein light beams emitted from a plurality of RGB light sources are substantially collimated.
14 . The scanning projection apparatus according to claim 1 , wherein light beams emitted from a plurality of RGB light sources are substantially perpendicular with each other.
15 . The scanning projection apparatus according to claim 1 , wherein a plurality of RGB light sources are so arranged to oppose to each other.
16 . The scanning projection apparatus according to claim 1 , wherein a light beam scanning means is arranged at a position opposite to a direction in which light beams emit from a plurality of RGB light sources.
17 . The scanning projection apparatus according to claim 1 ,
wherein the optical beam combiner comprises an optical glass or a transparent plastic for optics having a predetermined refractive index (n) and at least one smooth surface;
wherein a first light beam for image display emitted from a first light source of the two or more light sources is incident on the smooth surface of the optical beam combiner in a direction from an outside thereof towards an inside of the optical beam combiner at an incident angle (θ1) with respect to the smooth surface where it satisfies Equation (1) below,
θ1≈ TAN −1 [n] (1);
and
wherein a second light beam for image display emitted from a second light source is incident on the smooth surface of the optical beam combiner in a direction from an inside of the optical beam combiner to an outside of the combiner at an incident angle (θ 2 ) with respect to the smooth surface where it satisfies a relational Equation (2) below,
θ2>SIN −1 [1/ n] (2).
18 . The scanning projection apparatus according to claim 17 , wherein the first light beam for image display is a light beam linearly polarized in substantially parallel to a plane formed by a center optical axis of the first light beam for image display and a plane-normal to the smooth surface.
19 . The scanning projection apparatus according to claim 17 , wherein the optical beam combiner comprises an optical glass material or a transparent plastic material for optics having a refractive index of 1.60 or higher for a wavelength of visible light.
20 . The scanning projection apparatus according to claim 17 ,
wherein the optical beam combiner comprises an optical glass material or a transparent plastic material for optics having a refractive index of 1.60 to 1.65 for a wavelength of visible light;
wherein the incident angle (θ 1 ) of the first light beam for image display is set to a predetermined angle within an angle range of 60°±10°; and
wherein the incident angle (θ 2 ) of the second light beam for image display is set to a predetermined angle within an angle range of 43°±5°.