JP2000011721A - Optical part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical part capable of irradiating the irradiating object part in the comparatively uniform light quantity distribution, capable of reducing the number of reflecting surfaces and capable of reducing a loss by reflection on an interface. SOLUTION: In an optical part composed of a convex lens 1 and the reflecting surface 2 arranged at a prescribed angle with the optical axis of the convex lens, the optical part is constituted in such a way that the reflecting surface has a structure of a large number of recesses/projections of a prism type, this recess/projection structure is a structure that the nonreflective surface and the total reflection surface having an angle of 45 degrees to the optical axis of the convex lens are alternately arranged, and this total reflection surface can totally reflect the parallel light from the convex lens in the right-angles direction to the optical axis. The optical part is formed by arranging the light emitting end of an optical fiber 4 in a focal position of the convex lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical component comprising a convex lens and a total reflection surface useful for an air-rear sensor or the like.

[0002]

2. Description of the Related Art As a technique for improving detection accuracy in an air rear sensor using an optical fiber or the like, there is a means for equalizing the amount of light illuminating a detection area. For example, the light radiated from the optical fiber is made uniform light by passing through a shielding means having an opening having a narrow portion and a small amount of light corresponding to the light amount distribution and a small amount of light corresponding to the light amount distribution. There is known a means for changing the optical path by reflecting the light with a reflecting material such as the above, and then making the amount of light in a detection area uniform as parallel light with a convex lens (Japanese Patent Application Laid-Open No. 9-251104).

[0003]

However, in this technique, in order to make the outgoing light uniform, an opening with a large amount of light is used narrowly and a portion with a small amount of light is widened. A problem is that the number of parts increases because a reflecting mirror or the like for the purpose of bending is used. In addition, the use of separately molded optical components increases the man-hours required during assembly work, increases the number of interfaces, increases the loss due to Fresnel reflection, and tends to cause optical axis misalignment of each optical component. is there.

For example, in the case of a lens made of polymethyl methacrylate, the loss of light quantity due to Fresnel reflection is about 4% of the total light quantity at one interface, and if there are six interfaces, about 24% of the total light quantity is lost. Light is lost. Therefore, it is very important to reduce the number of interfaces in order to prevent a decrease in the amount of emitted light.

[0005]

The gist of the present invention is an optical component comprising a convex lens 1 and a reflecting surface 2 arranged at a predetermined angle with respect to the optical axis of the convex lens. The uneven structure has a structure in which non-reflective surfaces 21 and total reflection surfaces 22 having an angle of 45 degrees with respect to the optical axis of the convex lens are alternately arranged. An optical component capable of totally reflecting parallel light from a convex lens in a direction perpendicular to the optical axis.

The gist of the present invention resides in an optical component comprising the optical fiber 4 and the optical component, wherein the light emitting end of the optical fiber is located at the focal point of the convex lens.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The optical component of the present invention is a convex lens 1
And a reflecting surface 2 disposed at a predetermined angle to the optical axis of the convex lens. As shown in FIG. 1, the reflection surface is arranged at a predetermined distance from the convex lens such that the center thereof is located on the optical axis of the convex lens. In FIG. 1, the X direction is the direction of the optical axis of the convex lens, and the Y direction is a direction perpendicular to the direction. Although not shown, the Z direction is a direction perpendicular to the paper. The reflection surface 2 has a predetermined angle of less than 45 degrees with respect to the optical axis of the convex lens as a whole.

[0008] These optical parts are optical fibers 4
Can be an optical component arranged so that its light emitting end coincides with the position of the focal point of the convex lens. In this case, the other end of the optical fiber is connected to a light source, and light from the light source is emitted to the convex lens. Known optical fibers can be used, and the number thereof may be one or plural.

The reflecting surface has a number of prism-shaped uneven structures, in which a non-reflective surface 21 and a total reflecting surface 22 having an angle of 45 degrees with respect to the optical axis of the convex lens are alternately arranged. It is a structure (FIG. 2). And each total reflection surface is XY
It is formed with a predetermined length (width) in a direction perpendicular to the plane (Z direction). That is, the angle between each total reflection surface and the XZ plane is 45 degrees.

The total reflection surface 22 is usually a glass or transparent resin total reflection prism surface, but may be a reflection surface having a reflection material disposed on the back surface. Since the non-reflective surface 21 is not substantially used, its shape and material are not particularly limited.

Since light from a light source is usually incident on the convex lens from the focal point of the convex lens, light passing through the convex lens becomes light parallel to the optical axis. Since the total reflection surface has an angle of 45 degrees with respect to the optical axis of the convex lens, this parallel light is totally reflected in a direction perpendicular to the optical axis of the convex lens (Y direction).

In the light reflecting direction (Y direction) of the reflecting surface 2, a light shielding component 3 for adjusting the light amount distribution can be arranged as required. Of the parallel light that has passed through the convex lens, the amount of light near the optical axis is large, but the amount of light away from the optical axis is small. Therefore, of the light reflected from the reflecting surface 2 in the Y direction, the amount of light near the center of the reflecting surface is large, but the amount of light at a position farther from the center in the X direction is small. For this reason, in order to make the light amount distribution in the X direction uniform, for example, as shown in FIG. 4B, the light shielding component 3 has a narrower exit width of the exit light at a portion corresponding to the vicinity of the center of the reflection surface. Structure.

Although FIGS. 1 to 4 illustrate an optical component having a narrow width in the Z direction as an optical component whose longitudinal direction is in the X direction, an optical component having a wider width in the Z direction is illustrated. It can also be a part. In this case, a plurality of pairs of light incident portions composed of the convex lens light and the fiber are arranged in the Z direction.

The optical component of the present invention usually has a structure housed in a case 5. This optical component can be used as a light irradiating component or a light receiving component for an area sensor, a photoelectric switch, or the like. When used as an area sensor, for example, as shown in FIG. 5, one optical component can be arranged as a light irradiation unit 7 and the other optical component can be arranged as a light receiving unit 8. In the case where the light blocking member 6 does not exist between the light irradiating section and the light receiving section, the light is bent at an angle of 45 degrees on the reflecting surface at the light receiving section, and becomes parallel to the optical axis of the convex lens. Is collected. When a light-shielding object is present, the amount of received light decreases, so that the presence of the light-shielding object can be detected.

[0015]

The optical component of the present invention has the following excellent effects. 1) The light emitted from the point light source can irradiate a wide area with a relatively uniform light amount distribution. A sensor using this optical component can inspect a wide range of an inspection object as an air rear type sensor. 2) Since the number of light reflection surfaces is small and the loss due to reflection at the interface is small, the object can be detected with high sensitivity when used as an object detection sensor or the like.

[Brief description of the drawings]

FIG. 1 is a view showing a light path in an optical component of the present invention.

FIG. 2 is a partially enlarged view of a reflection surface.

FIG. 3 is a diagram showing a state where the optical component of the present invention is housed in a case.

4 (a), (b) and (c) are a plan view, a front view and a side view of the optical component of FIG. 3, respectively.

FIG. 5 is a diagram showing an example of an area sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Convex lens 2 Reflecting surface 3 Light shielding part 4 Optical fiber 5 Case 6 Shield 7 Light irradiation part 8 Light receiving part

Claims (3)

[Claims] 1. An optical component comprising a convex lens (1) and a reflecting surface (2) arranged at a predetermined angle with respect to the optical axis of the convex lens, wherein the reflecting surface has many prism-shaped uneven structures. This uneven structure is a structure in which non-reflection surfaces (21) and total reflection surfaces (22) having an angle of 45 degrees with respect to the optical axis of the convex lens are alternately arranged. Optical component that can totally reflect parallel light in the direction perpendicular to the optical axis. 2. An optical component according to claim 1, wherein a light shielding component for adjusting a light amount distribution is arranged in a light reflection direction of the reflection surface of the optical component according to claim 1. 3. An optical component comprising an optical fiber (4) and the optical component according to claim 1, wherein the light emitting end of the optical fiber is arranged at the position of the focal point of the convex lens.