JP2006105626A - Optical fiber sensor head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber sensor head capable of detecting long-term stable detection even under an environment where a metal material is easily deteriorated. <P>SOLUTION: The optical fiber sensor head 1 is equipped with an optical fiber 10 and a holder 14 in which the end part of the optical fiber 10 is inserted, and a collimator lens 19 for converting the light emitted from the leading end of the optical fiber 10 to parallel light to emit the same is provided in the holder 14. Further, a prism 20 is attached in front of the emission direction of the light of the collimator lens 19 and equipped with an incident surface 20A on which the emitted light from the collimator lens 19, a reflecting surface 20B arranged in the contact state with an air layer in the outside of the holder so as to reflect the light emitted from the incident surface 20A by an inner surface and an emission surface 20C for emitting the light from the reflecting surface 20B to the outside. Then, the emitted light from the collimator lens 19 is totally reflected by the reflecting surface 20B of the prism 20 to be emitted from the emission surface 20C toward a detection region. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical fiber sensor head.

Conventionally, an optical fiber sensor head called a side view type has been provided. For example, in the side view type optical fiber sensor head disclosed in Patent Document 1, a reflecting surface is formed on a reflector facing the detection end face of the optical fiber, and this reflecting surface is inclined with respect to the axial direction in the holding sleeve. Arranged to face the external space through the window hole. And the light radiate | emitted from an optical fiber is reflected in a reflective surface, and this reflected light is irradiated to the predetermined detection area | region in external space through a window part.
Japanese Patent Laid-Open No. 6-294741

  By the way, in the reflector in the conventional side view type optical fiber sensor head, in order to increase the reflectivity, the reflective surface is formed by performing metal deposition such as silver or aluminum, or performing a mirror polishing process on a stainless steel material. It was. However, there is a problem that such a reflective surface is made of a metal material and is used by exposing it to a detection target in an environment where the metal material is likely to deteriorate.

  For example, in some manufacturing processes of semiconductor wafers, detection is required in an environment where a corrosive gas (for example, hydrogen bromide gas) that easily corrodes a metal material exists. If the reflective surface of the metal material is exposed as in the technique shown in, the reflective surface may be corroded by gas when used in such a corrosive atmosphere, and accurate reflection may not be performed. There is.

  The present invention has been made based on the above-described circumstances, and an object thereof is to provide an optical fiber sensor head capable of performing long-term stable detection even in an environment in which a metal material is likely to deteriorate. .

As means for achieving the above object, the invention of claim 1 comprises an optical fiber,
In an optical fiber sensor head comprising a holder into which an end of the optical fiber is inserted,
A collimator lens that is arranged in the holder and converts the light irradiated from the tip of the optical fiber into parallel light and emits it;
The collimator lens is attached to the holder in the front of the light emission direction, and the incident surface on which the emitted light emitted from the collimator lens is incident, and the light incident from the incident surface is reflected by the inner surface. A translucent member comprising a reflecting surface arranged in contact with the air layer outside the holder, and an emitting surface for emitting the reflected light from the reflecting surface to the outside;
Have
The emitted light emitted from the collimator lens is emitted from the emission surface toward the detection region.

Invention of Claim 2 is the optical fiber sensor of Claim 1, The cap is attached to the said translucent member so that the said reflective surface of the said translucent member may be covered,
The cap covers the reflective surface in a state where the air layer is interposed between the cap and the translucent member.

  A third aspect of the present invention is the optical fiber sensor head according to the first or second aspect, wherein the holder is formed in a polygonal column shape.

  According to a fourth aspect of the present invention, in the optical fiber sensor head according to any one of the first to third aspects, the holder is made of titanium.

<Invention of Claim 1>
In the invention of claim 1, in the translucent member, the reflecting surface is provided in a state of being in contact with the air layer outside the holder so that the light incident from the incident surface is reflected by the inner surface of the translucent member. The reflected light from the reflecting surface is emitted to the outside from the emitting surface formed by the translucent member.

  That is, since the light-transmitting member having a large refractive index is incident on the air layer having a small refractive index, total reflection occurs at the boundary surface when the incident angle is larger than the critical angle. Utilizing this, the light emitted from the collimator lens is totally reflected and emitted from the emission surface. Therefore, since reflection is possible without configuring a reflective surface made of a metal material, even if used in an environment where the metal material is deteriorated, the reflective surface is not deteriorated due to the environment, Long-term stable detection is possible.

  In addition, since the translucent member is provided outside the holder, it is easy to wipe off contaminants even when contaminants (for example, dust or water droplets) adhere to the exit surface, and has excellent maintainability It becomes.

<Invention of Claim 2>
According to the invention of claim 2, since the reflection surface can be prevented from being exposed by the cap, it is possible to perform reflection with high accuracy without adhering substances such as water droplets and dust to the reflection surface, and thus stable detection is suitably performed. It can be carried out.

<Invention of Claim 3>
According to the invention of claim 3, since the holder is configured in a polygonal columnar shape, the light emission direction can be adjusted on the basis of the substantially flat outer surface of the holder configured in the polygonal columnar shape when mounting. The holder can be easily attached in consideration of the emission direction.

<Invention of Claim 4>
According to the invention of claim 4, even when the optical fiber sensor head is used in a corrosive atmosphere (for example, hydrogen bromide gas) that corrodes the metal material, the holder is made of titanium. Therefore, the holder is not corroded, and the holder can be effectively prevented from being deteriorated. As a result, a structure is obtained in which stable strength and structure are ensured over a long period of time.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.
1 is a side sectional view showing an example of an optical phi sensor head according to Embodiment 1 of the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a front view thereof. FIG. 4 is a view of the optical fiber sensor head according to the first embodiment as viewed in the axial direction from the cap side, and FIG. 5 is a perspective view of the optical fiber sensor head. FIG. 6 is an enlarged view showing a part of FIG.

  In FIG. 1, reference numeral 10 denotes an optical fiber, which has a circular cross section with a diameter of about 2 mm, for example, and is covered with an outer coating 11 on the outside, and a tip portion is exposed from the outer coating 11. The tip portion of the optical fiber 10 exposed from the outer coating 11 is accommodated in the inner sleeve 13. The inner sleeve 13 is made of resin and has a substantially cylindrical shape, and the tip of the optical fiber 10 is accommodated therein.

  The inner sleeve 13 is fitted with the holder 14 in the holder 14. The holder 14 is made of titanium and has a hollow shape (in detail, a cylindrical shape) as a whole, and a hole 17A for inserting a prism 20 (a prism corresponds to a light transmitting member) to be described later is formed at one end. A large-diameter portion 17 is provided, and a small-diameter portion 16 in which a hole 16A for inserting the optical fiber 10 is formed at the other end.

  In the inner sleeve 13, a slit portion 18 that is in close contact with the distal end surface of the optical fiber 10 is integrally formed on the back side where the optical fiber 10 is inserted, and the slit portion 18 includes the optical fiber 10. A slit 18A narrower than the tip surface is formed. A part of the collimator lens 19 is accommodated on the side of the inner sleeve 13 opposite to the optical fiber 10 across the slit portion 18. The collimator lens 19 is formed in a longitudinal shape, and a part of the collimator lens 19 is fitted in the inner sleeve 13, and another part different from the collimator lens 19 is fitted in the holder 14. The light irradiated in the axial direction of the optical fiber sensor head 1 is converted into parallel light and emitted to the prism 20 side. The end of the collimator lens 19 on the side opposite to the optical fiber 10 side is close to the prism 20 (for example, close to the contact or with a slight gap).

  The large diameter portion 17 of the holder 14 is provided with a prism 20 that takes in the emitted light emitted from the collimator lens 19 in front of the light emitting direction of the collimator lens 19 so as to transmit the inside. The internal arrangement portion 20D, which is a part of the prism 20, is inserted into the hole 17A and is fitted to the holder 14, and the external arrangement portion 20E is provided outside the holder 14. As shown in FIGS. 1 to 3, a stepped portion 20F having a larger outer diameter than the inner disposed portion 20D is formed in the outer disposed portion 20E. In the prism 20, the end surface of the stepped portion 20F is a holder. 14 is held by the holder 14 while being supported by the end face of the large-diameter portion 17. The inner surface of the holder 14 and the outer surface of the internal arrangement portion 20D are joined by an adhesive medium such as an adhesive.

  As shown in FIG. 1, the prism 20 is arranged outside the holder 14 so that the incident surface 20 </ b> A on which the emitted light emitted from the collimator lens 19 is incident and the light incident from the incident surface 20 </ b> A are reflected by the inner surface. And a reflecting surface 20B arranged in contact with the air layer. When the side where the optical fiber 10 is inserted in the axial direction of the optical fiber sensor head 1 is the rear side and the opposite side is the front side, the incident surface 20A is formed on the rear end side of the prism 20, and the reflecting surface 20B is It is formed on the front end side on the opposite side. The reflecting surface is a surface inclined by 45 ° with respect to the light emitting direction from the collimator lens 19 (that is, the longitudinal direction of the optical fiber sensor head 1).

  Furthermore, the side surface of the prism 20 is provided with an emission surface 20C for emitting the reflected light from the reflection surface 20B to the outside, and the emitted light emitted from the collimator lens 19 is directed from the emission surface 20C toward the detection region. It is comprised so that it may radiate | emit. The emission surface 20C of the prism 20 is formed in a planar shape, and has a configuration for emitting parallel light without converging and diffusing.

  Now, in the optical fiber sensor head of the present invention, in the prism 20, the reflecting surface 20B is in contact with the air layer 30 outside the holder so that the light incident from the incident surface 20A is reflected by the inner surface of the prism 20. The reflection light from the reflection surface 20B is provided so as to be emitted from the emission surface 20C formed on the side surface of the prism 20 to the outside. That is, since the light in the axial direction emitted from the collimator lens 19 is transmitted through the prism 20 and enters the air layer having a small refractive index from the prism 20 having a large refractive index, the incident angle is larger than the critical angle. In the present invention, the light emitted from the collimator lens 19 is totally reflected in the direction perpendicular to the axis and emitted from the output surface 20C. ing. Therefore, reflection is possible without configuring a reflecting surface made of a metal material, and even when used in an environment where the metal material is deteriorated, the reflecting surface 20B is not deteriorated due to the environment, and it is long-term. Stable detection is possible.

  As described above, in the configuration of the present embodiment, while the parallel light is emitted through the collimator lens 19 and the parallel light is totally reflected through the prism 20, the entire emission surface 20C is planar. Therefore, the reflected light is emitted from the emission surface 20C to the side detection region in a state where the parallelism is maintained (that is, without converging and diffusing at the emission surface 20C). . Furthermore, as shown in FIGS. 2, 3, and 5, the emission surface 20 </ b> C is formed in a planar shape on the side of the prism 20 and is disposed outside the holder 14. Therefore, even when a substance (for example, dust or water droplets) that contaminates the emission surface 20C adheres, the contaminant is easily wiped off, and the structure is excellent in maintainability. Here, the emission surface 20C is disposed in front of the stepped portion 20F and has a rectangular outer edge. In addition, although the emission surface 20C is formed in a flat shape here, the emission surface may be formed in a generally convex shape as long as the emission surface has no recess. In the present embodiment, the position of the inner surface of the holder 14 in the surface direction orthogonal to the axial direction of the holder 14 having the exit surface 20 </ b> C formed in an axial shape (the same direction as the exit direction from the collimator lens 19 in the present embodiment). Are provided in the same area or outside the area, and are more easily maintained. In this plane direction, the emission surface 20 </ b> C may be disposed slightly inside the position of the inner surface of the holder 14.

  A cap 22 made of a resin material is attached to the prism 20. As shown in FIGS. 2, 3, and 5, the cap 22 is attached to the prism 20 so as to cover a portion of the prism 20 arranged outside the holder 14 except for the emission surface 20 </ b> C. The cap 22 and the prism 20 are joined by an adhesive medium such as an adhesive in a state where the air layer 30 is sealed. Thus, since the cap 22 covers at least the reflection surface 20B with the air layer 30 interposed between the cap 20 and the prism 20, the exposure of the reflection surface 20B is prevented by the cap 22, and reflection is thereby achieved. Reflection with high accuracy is performed without substances such as water droplets and dust adhering to the surface 20B, and as a result, stable detection is suitably performed.

  Moreover, as shown in FIG.4 and FIG.5, the holder 14 is comprised by the polygonal column shape. Specifically, the outer surface of the holder 14 has eight surfaces (14A to 14H) and is configured in an octagonal column shape. The outer peripheral surface (that is, the eight surfaces 14A to 14H) of the holder 14 is constituted by a plurality of flat surfaces or substantially flat surfaces, and the outer edge shape (in other words, collimator) of the holder 14 viewed in the axial direction as shown in FIG. The outer edge shape of the cut surface obtained by cutting the holder 14 in a direction perpendicular to the light emission direction of the lens 19 is formed in a polygonal shape (an octagonal shape). Thus, since the holder 14 is configured in a polygonal column shape, the light emission direction can be adjusted with reference to the outer surface configured in the polygonal column shape when attached. Therefore, it is possible to easily perform the attachment work of the holder 14 so that the light emission direction is an arbitrary direction with reference to the outer surface of the holder 14. Although the outer shape of the holder 14 is an octagonal column here, it may be another polygonal column such as a hexagonal column.

  The holder 14 is made of a titanium material. Therefore, the holder 14 does not corrode even when used in a corrosive atmosphere (for example, hydrogen bromide gas) that easily corrodes the metal material, such as a part of the manufacturing process of the semiconductor wear. It is possible to effectively prevent the deterioration. As a result, stable strength and structure are ensured over a long period of time. Therefore, it is useful to use the optical fiber sensor head 1 as a semiconductor wear detection sensor that is used in a corrosive atmosphere such as hydrogen bromide gas.

1 is a side sectional view of an optical fiber sensor head according to Embodiment 1 of the present invention. Side view of the optical fiber sensor head of FIG. Front view of the optical fiber sensor head of FIG. FIG. 1 is a view of the optical fiber sensor head of FIG. 1 viewed from the cap side in the axial direction. 1 is a perspective view of the optical fiber sensor head of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical fiber sensor head 10 ... Optical fiber 14 ... Holder 19 ... Collimator lens 20 ... Prism (translucent member)
20A ... Incident surface 20B ... Reflective surface 20C ... Outgoing surface 22 ... Cap

Claims (4)

Optical fiber,
In an optical fiber sensor head comprising a holder into which an end of the optical fiber is inserted,
A collimator lens that is arranged in the holder and converts the light irradiated from the tip of the optical fiber into parallel light and emits it;
The collimator lens is attached to the holder in the front of the light emission direction, and the incident surface on which the emitted light emitted from the collimator lens is incident, and the light incident from the incident surface is reflected by the inner surface. A translucent member comprising a reflecting surface arranged in contact with the air layer outside the holder, and an emitting surface for emitting the reflected light from the reflecting surface to the outside;
Have
An optical fiber sensor head configured to emit the emitted light emitted from the collimator lens toward a detection region from the emission surface. A cap is attached to the translucent member so as to cover the reflective surface of the translucent member,
2. The optical fiber sensor head according to claim 1, wherein the cap covers the reflecting surface in a state where the air layer is interposed between the cap and the translucent member. The optical fiber sensor head according to claim 1, wherein the holder is formed in a polygonal column shape. The optical fiber sensor head according to any one of claims 1 to 3, wherein the holder is made of titanium.

Images