Display device, object apparatus, image forming unit and display method

Patent metadata

Field	Value
Publication number	US-11042029-B2
Application number	US-201816475496-A
Country	US
Kind code	B2
Filing date	Mar 14, 2018
Priority date	Mar 17, 2017
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A display device includes a light source unit, a light deflector configured to deflect light from the light source unit, an optical element array configured to be two-dimensionally scanned in a main-scanning direction and in a sub-scanning direction with light via the light deflector 15, the optical element array having a plurality of optical elements, and a light projecting unit configured to project light received via the optical element array. In the display device, each of a beam spot diameter in the sub-scanning direction on the optical element array and an arrangement pitch of the optical elements in the sub-scanning direction on the optical element array is equal to or greater than a scanning line pitch on the optical element array.

First claim

The invention claimed is:

1. A display device comprising:
a light source unit;
a light deflector configured to deflect light from the light source unit;
an optical element array including a plurality of optical elements;
a light deflector configured to deflect light from the light source unit to two-dimensionally scan the optical element array in a main-scanning direction and a sub-scanning direction; and
a light projecting unit configured to project light received via the optical element array, wherein
each of a beam spot diameter in the sub-scanning direction on the optical element array and an arrangement pitch of the optical elements in the sub-scanning direction on the optical element array is equal to or greater than a scanning line pitch on the optical element array, and
when the arrangement pitch is Plens, the scanning line pitch defines as an interval between the adjacent scanning lines at a position with respect to the main-scanning direction where the interval becomes widest between the adjacent scanning lines on the optical element array is Pscan, and the pixel density in the sub-scanning direction of the display device is Ycpd, respective values for Ycpd, Plens, and Pscan are set such that the moiré frequency fmoiré obtained by fmoiré=Ycpd(Plens−Pscan)/2Pscan is 10 cycles per degree or more.

2. The display device according to claim 1 , wherein
a width of the optical element in the sub-scanning direction is equal to or greater than the scanning line pitch.

3. The display device according to claim 1 , wherein
when the beam spot diameter is W beam , and a moiré contrast is C moire , the following formulas are established:
f moire =Y epd ( P lens −P scan )/2 P scan ;
C moire =−0.9× W beam /P scan +1.6; and

0.5/5.05Done×exp(−0.138 f moire )×(1.0−exp(−0.1) f moire )≥ C moire .

4. The display device according to claim 1 , wherein
when the beam spot diameter is W beam , the moiré contrast C moire obtained by C moire =−0.9×W beam /P scan +1.6 is 0.5 or less.

5. The display device according to claim 1 , wherein
optical centers of the optical elements adjacent to each other in the main-scanning direction in the optical element array are shifted in the sub-scanning direction.

6. The display device according to claim 1 , wherein
each of the plurality of optical elements has a hexagonal shape in plan view, and the plurality of optical elements are arranged in a honeycomb structure.

7. The display device according to claim 1 , wherein
each of the beam spot diameter in the main-scanning direction on the optical element array and the arrangement pitch in the main-scanning direction of the optical elements in the optical element array is equal to or greater than a center-to-center interval between beam spots adjacent in the main-scanning direction on the optical element array.

8. The display device as claimed in claim 7 , wherein
a width of the optical element in the main-scanning direction is equal to or greater than the center-to-center interval.

9. An object apparatus comprising:
an object provided with a transreflective member and
the display device according to claim 1 mounted on the object and configured to project light onto the transreflective member.

10. The object apparatus according to claim 9 , wherein
the object is a movable object.

11. A display method comprising:
forming an image by two-dimensionally scanning an optical element array including a plurality of optical elements in a main-scanning direction and in a sub-scanning direction; and
projecting the image formed by the two-dimensional scanning of the optical element array to display a projected image, wherein
each of a beam spot diameter in the sub-scanning direction on the optical element array and an arrangement pitch of the optical elements in the sub-scanning direction on the optical element array is equal to or greater than a scanning line pitch on the optical element array, and
when the arrangement pitch is Plens, the scanning line pitch defines as an interval between the adjacent scanning lines at a position with respect to the main-scanning direction where the interval becomes widest between the adjacent scanning lines on the optical element array is Pscan, and the pixel density in the sub-scanning direction of the display device is Ycpd, respective values for Ycpd, Plens, and Pscan are set such that the moire frequency fmoiré obtained by fmoiré=Ycpd(Plens−Pscan)/2Pscan is 10 cycles per degree or more.

Assignees

• Tanabe Hiroyuki
• Kishi Yumiko
• Inamoto Makoto
• Ricoh Co Ltd

Inventors

• Tanabe Hiroyuki
• Kishi Yumiko
• Inamoto Makoto

Classifications

• G02B2027/014

  comprising information/image processing systems · CPC title

• G02B27/0905

  Dividing and/or superposing multiple light beams · CPC title

• G02B27/14

  operating by reflection only · CPC title

• G02B3/0056

  arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses (G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085) · CPC title

• G02B2027/0145

  creating an intermediate image · CPC title