Transmission type photoelectric sensor, element holder assembled therein and manufacturing method thereof

• US 20040104335A1
• Filed: 11/12/2003
• Published: 06/03/2004
• Est. Priority Date: 11/13/2002
• Status: Abandoned Application

• Current Assignee: Keyence Corporation (Keyence)
• Original Assignee: Keyence Corporation (Keyence)
• Inventors: Sakaguchi, Tomikazu
• Application Number:
  US10/704,792
• Publication Number:
  US 20040104335A1
• Time in Patent Office: Days
• US Class Current: 250/221
• CPC Class Codes: G01V 8/10 Detecting, e.g. by using light barriers by reflection from the object G01S17/00

Abstract

An element holder is a single-piece member integrally having a light-blocking component for limiting the spread angle of light. The element holder includes a cylindrical internal path and can detachably hold an optical element on one end. A lens is affixed on the opposite end of the element holder. The element holder is a molded plastic product, and includes a single light-blocking wall integrally molded with the element holder to extend across the internal path in a level approximately equally spaced from the optical element and the lens to limit the spread angle of light.

Claims

1. A transmission type photoelectric sensor comprising:

an optical element;

a plastic element holder having a base wall which has an aperture and detachably contacts said optical element; and

a lens positioned adjacent to the element holder opposite from the base wall,

wherein the element holder includes;

a light path extending from the aperture of the base wall to said lens; and

an intermediate light-blocking wall extending in a substantially equally spaced level from the base wall and the lens to limit the spread angle of light, and

wherein the element holder is a single-piece molded product including the intermediate light-blocking wall.

2. The transmission type photoelectric sensor according to claim 1, wherein a wall defining the light path has a dark color.

3. The transmission type photoelectric sensor according to claim 1, wherein the element holder includes a sidewall defining the light path has an opening from the base wall to the intermediate light-blocking wall to expose a corresponding part of the light path externally through the opening.

4. The transmission type photoelectric sensor according to claim 3, wherein the aperture in the base wall increases in diameter toward the optical element, and the intermediate light-blocking wall includes a through hole that increases in diameter toward the lens.

5. The transmission type photoelectric sensor according to claim 4, wherein the transmission type photoelectric sensor is a multi-beam photoelectric sensor having a plurality of optical axes.

6. The transmission type photoelectric sensor according to claim 1, wherein the aperture in the base wall increases in diameter toward the optical element, and the intermediate light-blocking wall includes a through hole that increases in diameter toward the lens.

7. The transmission type photoelectric sensor according to claim 1, wherein the transmission type photoelectric sensor is a multi-beam photoelectric sensor having a plurality of optical axes.

8. A transmission type photoelectric sensor comprising:

an optical element for emitting or detecting light through a lens;

a holding portion for holding the optical element;

an aperture formed in the holding portion in optical alignment with the optical element;

a sidewall defining a light path from the aperture to the lens;

a light-blocking wall extending from the sidewall;

a through hole formed in the light-blocking wall to define a part of the light path; and

an opening formed in the sidewall defining the part of the light path from the aperture to the light-blocking wall to expose the adjacent part of the light path externally through the opening.

9. The transmission type photoelectric sensor according to claim 8, wherein the aperture in the base wall increases in diameter toward the optical element, and the through hole in the light-blocking wall increases in diameter toward the lens.

10. The transmission type photoelectric sensor according to claim 9, wherein the transmission type photoelectric sensor is a multi-beam photoelectric sensor having a plurality of optical axes.

11. A plastic element holder unit to be assembled in a transmission type photoelectric sensor for holding a plurality of optical elements in equal intervals and permitting the optical elements to emit or receive light through lenses, comprising:

a plurality of element holder portions for holding the individual optical elements therein, each said element holder portion including;

a base wall for detachably receiving each said optical element;

an aperture formed in a position of the base wall in optical alignment with the optical element;

a sidewall defining a light path extending from the base wall to the lens;

an intermediate light-blocking wall which is integral with the sidewall and extends across the light path from the aperture to the lens to limit the spread angle of light; and

an opening formed in the sidewall defining the part of the light path from the base wall to the intermediate light-blocking wall,

wherein the element holder is a single-piece product.

12. The element holder unit according to claim 11, wherein the sidewall has a dark color.

13. The element holder unit according to claim 11 wherein the sidewall has an opening from the base wall to the intermediate light-blocking wall to expose the corresponding part of the light path externally through the opening.

14. The element holder unit according to claim 13, wherein the aperture in the base wall increases in diameter toward the optical element, and the through hole in the intermediate light-blocking wall increases in diameter toward the lens.

15. The element holder unit according to claim 14, wherein the transmission type photoelectric sensor is a multi-beam photoelectric sensor having a plurality of optical axes.

16. A method of manufacturing a plastic element holder to be assembled in a transmission type photoelectric sensor for detachably holding an optical element, which element holder includes a light path extending from an aperture formed in the base wall in optical alignment with the optical element to the lens;

and an intermediate light-blocking wall extending across the light path in a level substantially equally spaced from the base wall and the lens and having a through hole to limit the spread angle of light, comprising the steps of;

simultaneously setting a first die for making a lens-side half of the light path from the lens to the intermediate light-blocking wall and movable in parallel to the optical axis and a second die for a element-side half of the light path from the base wall to the intermediate light-blocking wall and movable across the optical axis; and

injecting a material into a mold to make the lens-side half of the light path, the intermediate light-blocking wall and the element-side half of the light path.

17. The method according to claim 16, wherein the method includes providing the first die with a first projection on one surface thereof to make the through hole in the intermediate light-blocking wall.

18. The method according to claim 17, wherein the method includes simultaneously setting a third die in position with the first and second dies to make an element receiving portion for holding the optical element, and then performing said step of injecting a material into a mold to form the lens-side half of the light path, the intermediate light-blocking wall, the element-side half of the light path and the element receiving portion simultaneously.

19. The method according to claim 18 wherein the method includes providing the third die with a second projection on one surface thereof to make the aperture in the base wall.