Light barrier optical module

• US 6,348,685 B1
• Filed: 03/11/1999
• Issued: 02/19/2002
• Est. Priority Date: 03/11/1998
• Status: Expired due to Fees

• Current Assignee: Schneider Electric SA (Schneider Electric SE)
• Original Assignee: Schneider Electric SA (Schneider Electric SE)
• Inventors: Givet, Jean-Bernard
• Primary Examiner(s): EVANS, FANNIE L
• Application Number:
  US09/266,574
• Time in Patent Office: 1,076 Days
• Field of Search: 250/221, 250/222.1, 250/222.2, 250/216, 250/237.R, 250/214.B, 250/214.C, 250/239, 340/555, 340/556, 340/557
• US Class Current: 250/221
• CPC Class Codes: G01D 5/34 the beams of light being detected by photocells
• CPC Class Codes: G01V 8/10 Detecting, e.g. by using light barriers by reflection from the object G01S17/00

Abstract

An improved light barrier optical module including a system of one or more light blocking partitions. The partitions have different sized orifices configured to reduce the effects of parasitic light rays which would otherwise interfere with the reliable operation of the module. The module is suitable for both the transmission and reception of light barrier beams and for production using injection molding.

Claims

1. An optical module for a light barrier, comprising:

at least one of an optoelectronic emission component and an optoelectronic reception component;

an optical transmission device configured to focus the light, centered on an optical axis, and having an useful optical area with diameter D1 around the optical axis;

a rear wall defining a rear wall orifice centered on the optical axis, the rear wall orifice having an diameter D3 around the optical axis wherein D3<

D1; and

a diaphragm positioned to block reflected light within a chosen reflection zone and comprising a first partition defining a first partition orifice centered on the optical axis between the rear wall and the transmission device, the first partition orifice having a diameter D2A wherein D3<

D2A<

D1.

2. The optical module according to claim 1, further comprising:

another diaphragm comprising a second partition defining a second partition orifice centered on the optical axis between the transmission device and the first partition, the second partition orifice having a diameter D2B wherein D3<

D2A<

D2B<

D1.

3. The optical module according to claim 1, wherein:

the first partition is connected to one of (a) a front wall and (b) a rear wall and another partition through spacers which are provided with walls located apart from the optical axis by a given distance relative to the diameters of the partition orifices so as to minimize parasitic reflections.

4. The optical module according to claim 1, further comprising:

a body formed of a front wall and a back wall separated by at least one partition provided with an orifice;

a front wall defining a front orifice located on the optical axis;

a front panel with at least one lens located on the optical axis fixed to the front wall; and

at least one of a beam entry orifice and an beam exit orifice located on the optical axis,

wherein the walls and partitions are connected together through spacers, said spacers comprising supportive walls aligned substantially parallel to the optical axis and configured to fixedly hold at least the front wall, the back wall, and said at least one partition in alignment along the optical axis.

5. The optical module according to claim 4, wherein the body comprises means for attaching the body to a housing.

6. The optical module according to claim 4, wherein the body comprises positioning broaches projecting forward from the front wall, and wherein the front panel comprises recesses corresponding to the broaches for positioning the front panel on the body.

7. The optical module according to claim 4, wherein the body and the front panel are made by injection molding.