Image display device
View Patent ↗An image display device includes a light source, a scanner, a screen, a virtual image optical system and a screen incident angle correcting optical system. The light source emits laser light. The scanner scans the laser light. An image is formed on the screen by the scanned laser light. The virtual image optical system generates a virtual image of the image by the laser light having transmitted through the screen. The screen incident angle correcting optical system orients the scanned laser light toward the screen. The scanner performs at least first scanning and second scanning that has a scanning direction different from a scanning direction of the first scanning. The screen includes a lenticular lens having a lens pitch in a direction parallel to the first scanning. The lens pitch of the lenticular lens is larger than a beam diameter of the laser light near a light receiving surface of the screen.
1. An image display device comprising:
a light source which emits laser light;
a scanner which scans the laser light emitted from the light source;
a screen on which an image is formed by the laser light scanned with the scanner;
a virtual image optical system which generates a virtual image of the image by the laser light having transmitted through the screen; and
a screen incident angle correcting optical system which orients the laser light scanned with the scanner toward the screen, wherein:
the scanner performs at least first scanning and second scanning that has a scanning direction different from a scanning direction of the first scanning, and makes a scanning speed of the first scanning higher than a scanning speed of the second scanning,
the virtual image optical system generates the virtual image larger than the image formed on the screen,
the screen incident angle correcting optical system makes the laser light perpendicularly incident to a light receiving surface of the screen,
the screen includes a lenticular lens having a lens pitch in a direction parallel to the scanning direction of the first scanning and a louver structure having an inter-louver pitch in a direction parallel to the scanning direction of the second scanning,
the lens pitch of the lenticular lens is larger than a beam diameter of the laser light near the light receiving surface of the screen, and
the inter-louver pitch of the louver structure is smaller than the lens pitch of the lenticular lens.
2. The image display device according to claim 1 , wherein the screen incident angle correcting optical system is a telecentric f-θ lens.
3. The image display device according to claim 1 , wherein the screen causes the lenticular lens to function as a light receiving surface, and causes a wedge surface of the louver structure to function as an emission surface.
4. The image display device according to claim 1 , wherein the louver structure includes a reflecting function of reflecting the laser light and an absorbing function of absorbing the laser light, and switches the reflecting function and the absorbing function according to an incident angle of the laser light.
5. The image display device according to claim 1 , wherein a transverse mode in the light source is a single mode.
6. The image display device according to claim 1 , wherein at least one of a red light source, a green light source and a blue light source constituting the light source lights up only once while one pixel is illuminated.
7. The image display device according to claim 1 , wherein a diameter of a mirror constituting the scanner is from 0.8 mm to 1.5 mm both inclusive.
8. An image display device comprising:
a light source which emits laser light;
a scanner which scans the laser light emitted from the light source;
a screen on which an image is formed by the laser light scanned with the scanner;
a virtual image optical system which generates a virtual image of the image by the laser light having transmitted through the screen; and
a screen incident angle correcting optical system which orients the laser light scanned with the scanner toward the screen, wherein:
the scanner performs at least first scanning and second scanning that has a scanning direction different from a scanning direction of the first scanning, and makes a scanning speed of the first scanning higher than a scanning speed of the second scanning,
the virtual image optical system generates the virtual image larger than the image formed on the screen,
the screen incident angle correcting optical system makes the laser light perpendicularly incident to a light receiving surface of the screen,
the screen includes a first lenticular lens including a first lens pitch in a direction parallel to the scanning direction of the first scanning and a second lenticular lens including a second lens pitch in a direction parallel to the scanning direction of the second scanning,
the first lenticular lens and the second lenticular lens are arranged along an optical axis on which the laser light is incident, and
the second lens pitch of the second lenticular lens is smaller than the first lens pitch of the first lenticular lens.
9. The image display device according to claim 8 , wherein the first lenticular lens and the second lenticular lens are disposed at a top surface of the screen and at a back surface of the screen, respectively.
10. The image display device according to claim 8 , wherein the first lens pitch of the first lenticular lens satisfies the following equation,
0.2
≦
Px
D
≦
(
A
32
)
-
1
3
where Px represents the first lens pitch of the first lenticular lens, D represents a beam diameter of the laser light, and A represents effective optical magnification of the virtual image optical system.
11. The image display device according to claim 8 , wherein the scanning direction of the first scanning is orthogonal to the scanning direction of the second scanning.