Lens unit, exposure device, reading head, image forming apparatus, and image reading apparatus

Patent metadata

Field	Value
Publication number	US-11199650-B2
Application number	US-202016788521-A
Country	US
Kind code	B2
Filing date	Feb 12, 2020
Priority date	Mar 14, 2019
Publication date	Dec 14, 2021
Grant date	Dec 14, 2021

Abstract

The lens unit includes a first lens array including a plurality of first lens elements each of which has a first optical axis and which are arranged in an arrangement direction perpendicular to the first optical axis. A second lens array includes a plurality of second lens elements each of which has a second optical axis and which are arranged in the arrangement direction while facing the first lens elements. The second lens array is in a positional relationship relative to the first lens array such that the second lens array is rotated about a virtual line perpendicular to both the first optical axis and the arrangement direction as the rotational axis by 180 degrees. The optical axes of the lens elements located at the substantially centers of the lens arrays in the arrangement direction are arranged to substantially coincide with each other.

First claim

What is claimed is:

1. A lens unit comprising:
a first lens array including a plurality of first lens elements each of which has a first optical axis, the first lens elements being arranged in an arrangement direction perpendicular to the first optical axis; and
a second lens array including a plurality of second lens elements facing the first lens elements, each of the second lens elements having a second optical axis, the second lens elements being arranged in the arrangement direction, and
a light shielding member disposed between the first lens array and the second lens array, the light shielding member including a plurality of openings arranged in the arrangement direction,
wherein the second lens array is in a positional relationship relative to the first lens array such that the second lens array is rotated about a virtual line perpendicular to both the first optical axis and the arrangement direction as a rotational axis by 180 degrees,
wherein the first optical axis of the first lens element located at a substantially center of the first lens array in the arrangement direction and the second optical axis of the second lens element located at a substantially center of the second lens array in the arrangement direction are arranged to substantially coincide with each other,
wherein the first lens array includes a first positioning portion located at the substantially center in the arrangement direction, and the second lens array includes a second positioning portion located at the substantially center in the arrangement direction,
wherein the light shielding member includes a first fitting portion into which the first positioning portion is fitted and a second fitting portion into which the second positioning portion is fitted, and
wherein the first positioning portion and the second positioning portion are respectively fitted into the first fitting portion and the second fitting portion so that the first positioning portion and the second positioning portion face each other in a direction of the first optical axis via the light shielding member.

2. The lens unit according to claim 1 , wherein the virtual line is located at the substantially center of the first lens array in the arrangement direction.

3. The lens unit according to claim 1 , wherein the virtual line is located to pass through the first optical axis of one of the first lens elements in the first lens array or through an intermediate portion between two first lens elements in the first lens array adjacent to each other in the arrangement direction.

4. The lens unit according to claim 1 , wherein the first lens array includes a first engaging portion on a side facing the light shielding member, and the second lens array includes a second engaging portion on a side facing the light shielding member,
wherein the light shielding member includes a first engaged portion with which the first engaging portion engages and a second engaged portion with which the second engaging portion engages, and
wherein the second engaged portion of the light shielding portion is formed to be engaged with the second engaging portion on a condition that:
the second lens array is in a positional relationship relative to the first lens array such that the second lens array is rotated about the virtual line as the rotational axis by 180 degrees, and
the first optical axis of the first lens element located at the substantially center of the first lens array and the second optical axis of the second lens element located at the substantially center of the second lens array are arranged to substantially coincide with each other.

5. The lens unit according to claim 4 , wherein the first engaged portion and the second engaged portion are formed on opposite sides to each other with respect to the center of the light shielding member in the arrangement direction.

6. The lens unit according to claim 1 , wherein the light shielding member includes a first guide portion configured to position the first lens array in a direction of the rotational axis and a second guide portion configured to position the second lens array in the direction of the rotational axis.

7. The lens unit according to claim 1 , wherein the first lens array and the second lens array have the same shape as each other.

8. The lens unit according to claim 7 , wherein the first lens elements in the first lens array are arranged in two rows, and
wherein the second lens elements in the second lens array are arranged in two rows.

9. The lens unit according to claim 1 , wherein each of the first lens array and the second lens array is integrally formed of resin.

10. The lens unit according to claim 9 , wherein the substantially center of the first lens array in the arrangement direction corresponds to a position of a gate of a mold for forming the first lens array, and the substantially center of the second lens array in the arrangement direction corresponds to a position of a gate of a mold for forming the second lens array.

11. The lens unit according to claim 1 , wherein the first lens array and the second lens array are arranged in such a manner that the first optical axis of each of the plurality of first lens elements and the second optical axis of each of the plurality of second lens elements substantially coincide with each other.

12. The lens unit according to claim 1 , wherein the lens unit collects light from a plurality of optical elements or collects light onto the plurality of optical elements,
wherein m represents a magnification of the first lens element,
wherein XE represents a size of the optical element in the arrangement direction,
wherein ΔP represents a deviation of an arrangement interval of the first lens elements in the arrangement direction, and
wherein ΔP is in the following range:
0<ΔP<XE/m.

13. The lens unit according to claim 12 , wherein ΔP is in the following range:
0<ΔP<3.3.

14. An exposure device comprising:
the lens unit according to claim 1 , and
a light emitting element disposed to face the lens unit.

15. An image forming apparatus comprising:
the exposure device according to claim 14 ;
an image bearing body disposed to face the exposure device;
a developing portion configured to develop a latent image formed by the exposure device on the image bearing body; and
a transfer portion configured to transfer the image developed by the developing portion to a medium.

16. A reading head comprising:
the lens unit according to claim 1 ; and
a light receiving element disposed to face the lens unit.

17. An image reading apparatus comprising:
the reading head according to claim 16 ; and
a support table configured to hold a reading object at a position at which the reading object faces the reading head.

Assignees

• Oki Electric Ind Co Ltd

Inventors

• Nagamine Masamitsu
• Nakamichi Ren
• Yamamura Akihiro

Classifications

• G03G15/04036 Primary

  Details of illuminating systems, e.g. lamps, reflectors (lamp housings for copying cameras, reflex exposure lighting G03B27/542) · CPC title

• G03G2215/0668

  Toner discharging opening at one axial end · CPC title

• G03B27/523

  for full time exposure · CPC title

• B41J11/46

  by marks or formations on the paper being fed · CPC title

• G02B3/0056 Primary

  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