JP2001264453A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely move a lens to a light emitting part in the optical axis direction while accurately maintaining the lens central position to the optical axis of light outputted from the light emitting part. SOLUTION: A laser diode 13 is fixed to a laser holder 12, a guide part 14 is fixed to the laser holder 12, and a lens holder 15 holding a light projection lens 16 receiving light outputted from the laser diode 13 is supported slidably in the optical axis direction of the light outputted from the laser diode 13 by means of the guide part 14. A lens barrel part 18 screwed onto the lens holder 15 is supported with a lens barrel holding part 19 and a lens barrel cover 20 in a case 11 rotationally around the optical axis direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device capable of projecting light output from a light emitting unit through a lens and adjusting the position of the lens with respect to the light emitting unit.

[0002]

2. Description of the Related Art Conventionally, photoelectric switches have been used to detect the presence or absence of an object on a production line of a factory or the like.
This photoelectric switch adjusts the distance between the photoelectric switch and the object so that the object is located within the detection area of the photoelectric switch, projects light on the detection area of the object, and receives return light from the object, This is to determine the presence or absence of an object.

One of such conventional photoelectric switches is as follows.
In order to adjust the detection distance to the object, a laser diode serving as a light emitting part is fixed to a cylindrical light emitting part holder having a female screw formed on the inner peripheral surface, and a male screw screwed to the female screw of the light emitting part holder has an outer peripheral surface. There is a lens in which a lens is fixed to a lens holder formed as described above, and a male screw of the lens holder is screwed into a female screw of the light emitting unit holder. In this photoelectric switch, the position of the lens with respect to the light emitting unit is moved by rotating the lens holder with respect to the light emitting unit holder, and the spot shape and the spot position of the light projected from the lens on the object are changed, and The spot is adjusted according to the distance from the photoelectric switch.

Further, in the above-mentioned conventional photoelectric switch, a nut-shaped locking member having a female screw portion similar to that of the light emitting portion holder formed on the inner peripheral surface thereof is screwed into the female screw portion of the lens holder, and the lock portion is tightened. As a result, the end face of the lock section and the end face of the light emitting section holder are brought into contact with each other to lock the position of the lens with respect to the light emitting section.

[0005]

In the above-described conventional photoelectric switch, since the lens holder is moved by the screw mechanism, the lens is moved with respect to the light emitting portion by the play of the screw mechanism caused by the clearance between the male screw and the female screw. The position shifts, the spot shape of the projected light on the object changes, or the spot position changes.

Further, since the lens holder is rotated by the screw mechanism, the lens itself fixed to the lens holder also rotates, and when the center of the lens is shifted with respect to the optical axis of the light output from the light emitting section, With the rotation of the holder, the center of the lens rotates around the optical axis, and also in this case, the spot shape of the projected light on the object changes or the spot position changes.

Further, when the lens position is locked by tightening the lens holder with the nut-shaped locking member, the position of the lens moves by the amount of play of the screw mechanism before and after the locking operation, and the position is adjusted from the adjusted position. As a result, the position of the lens is displaced, so that the spot shape of the projected light on the object changes or the spot position changes.

In order to solve the above problem, it is conceivable to increase the distance between the light emitting unit and the lens to reduce the allowable value of the deviation of the lens from the optical axis. Is fixed, the amount of light incident on the lens surface with respect to the amount of light emitted from the light emitting unit is reduced, and the efficiency of light entering the lens is reduced. Further, if the area of the lens is increased in order to increase the efficiency of light entering the lens, the size of the light projecting portion is increased.

An object of the present invention is to move a lens with respect to a light emitting unit in the optical axis direction with high accuracy while maintaining the center position of the lens with respect to the optical axis of light output from the light emitting unit with high accuracy. It is to provide an optical device which can be used.

[0010]

Means for Solving the Problems and Effects of the Invention (1)
An optical device according to a first aspect of the present invention is an optical device that emits light and is fixed to a device main body, receives a light emitting unit that outputs light, and receives light output from the light emitting unit. Lens and
A lens holding portion for holding the lens, a supporting portion fixed to the device main body and supporting the lens holding portion in a state of being slidable in the optical axis direction of light output from the light emitting portion, and rotatable with the device main body It is supported in a state and includes a rotating unit that is screwed with the lens holding unit.

In the optical device according to the present invention, the light emitting portion for outputting light is fixed to the device main body, and the lens holding portion for holding the lens for receiving the light output from the light emitting portion is fixed to the device main body. The portion is supported so as to be slidable in the optical axis direction of the light output from the light emitting portion. Therefore, the support portion functions as a slide bearing with respect to the lens holding portion, and the lens holding portion, that is, the lens is moved with respect to the light emitting portion in a state without a large play such as a screw mechanism in a direction perpendicular to the optical axis. The lens can be slid in the axial direction, and the lens can be moved with high precision with respect to the light emitting unit.

In addition, since the rotating portion screwed to the lens holding portion is supported by the apparatus main body in a rotatable state about the optical axis direction of the light output from the light emitting portion, the rotating portion is rotated. Accordingly, the lens holding unit screwed to the rotating unit can be moved in the optical axis direction. At this time, the rotation unit rotates, and the lens holding unit slides in accordance with the rotation of the rotation unit. Therefore, the lens holding unit, that is, the lens moves in the optical axis direction without rotating. Therefore, it is possible to move the lens in a state where the center position of the lens in the optical axis direction of the light output from the light emitting unit is maintained at a position adjusted with high precision at the time of assembly.

As a result, it is possible to move the lens with respect to the light emitting unit in the optical axis direction with high accuracy while maintaining the center position of the lens with respect to the optical axis of the light output from the light emitting unit with high accuracy.

(2) Second invention In the optical device according to the second invention, in the configuration of the optical device according to the first invention, the lens holding unit is urged in the optical axis direction of the light output from the light emitting unit. Further, there is provided an urging means.

In this case, since the lens holding portion is urged in the optical axis direction of the light output from the light emitting portion, it is possible to eliminate play in the optical axis direction at the screwing portion between the lens holding portion and the rotating portion. It is possible to slide and move in the optical axis direction with higher precision.

(3) Third invention In the optical device according to the third invention, in the configuration of the optical device according to the first or second invention, the rotating portion is formed along the rotation direction of the rotating portion. Including a plurality of locking portions, by moving in the optical axis direction of the light output from the light emitting portion or rotating about the direction intersecting the optical axis direction as a center of rotation, between the adjacent locking portions of the plurality of locking portions It further includes a lock portion interposed to lock the rotation of the rotating portion.

In this case, the lock portion is formed along the rotation direction of the rotating portion by moving the lock portion in the optical axis direction of the light output from the light emitting portion or rotating the lock portion around a direction intersecting the optical axis direction. A locking portion is interposed between adjacent locking portions of the plurality of locking portions, and rotation of the rotating portion is locked.
As described above, since the lock portion is interposed along the optical axis direction of the light, that is, along the rotation center axis of the rotation portion, the rotation portion can be locked without substantially rotating the rotation portion. Further, even if the lock portion abuts on the lock portion when the lock portion is interposed between the lock portions, the stress from the lock portion can be released by slightly rotating the rotating portion,
Unnecessary stress is not applied to the lens holding unit and the lens from the lock unit via the rotating unit. As a result, it is possible to lock the lens in a state where the position of the lens is adjusted with high precision without substantially changing the position of the lens with respect to the light emitting unit before and after the locking operation.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a photoelectric switch will be described as an example of the optical device according to the present invention. The photoelectric switch has a light emitting means for generating light and a light receiving means for receiving the light and outputting a light receiving signal according to the amount of received light, and projects the light generated by the light emitting means to a detection area and from the detection area. The presence or absence of an object in the detection area is detected by receiving the return light of the above by the light receiving means.

FIG. 1 is an external perspective view of a photoelectric switch according to an embodiment of the present invention as viewed from one direction, and FIG.
FIG. 2 is an external perspective view of the photoelectric switch of FIG. 1 viewed from another direction.

In the photoelectric switch 1 shown in FIGS. 1 and 2, a light emitting section 2 serving as light emitting means for emitting light is provided in a case 11 serving as a housing, and the light emitting section 2 is provided beside the light emitting section 2. A light receiving unit 3 is provided as a light receiving unit that receives reflected light reflected by an object that receives light projected from the light source. The photoelectric switch 1 receives the light incident on the light receiving unit 3 out of the light reflected by the object receiving the light emitted from the light emitting unit 2, detects the presence or absence of the object based on the amount of received light, and outputs the detection result. I do.

A display unit 4 is provided on the side of the case 11 of the photoelectric switch 1 opposite to the light emitting / receiving surface on which the light emitting unit 2 and the light receiving unit 3 are provided, that is, on the back of the light emitting / receiving surface.
The display unit 4 is provided with an LED (light emitting diode) or the like, and displays the amount of light received by the light receiving unit 3 and the like.

The light projecting section 2 can change the position of the light projecting lens with respect to a laser diode serving as an internal light emitting section by rotating the lens barrel cover 20 in the direction of the arrow in the figure, as described below. To change the focal length to adjust the shape and position of the spot on the object.

FIG. 3 is a partial cross-sectional view mainly showing the light projecting portion 2 of the photoelectric switch shown in FIG. 1, and FIG. 4 is a partial cross-sectional view of the light projecting portion shown in FIG. It is.

As shown in FIG. 3 and FIG.
The laser holder 12 is integrally formed on a side surface provided substantially perpendicular to the light receiving and emitting surface of the laser light emitting device. Laser holder 1
A through-hole is formed at the center of 2, and a laser diode 13 serving as a light emitting unit is inserted into the through-hole, and the laser diode 13 is fixed to the laser holder 12.

The laser holder 12 is fitted with a guide portion 14 serving as a support portion for slidably supporting a lens holder 15 serving as a lens holding portion. A light projecting lens 16 is fixed inside the lens holder 15. The lens holder 15 is inserted into the cylindrical guide portion 14 in a highly accurate fitting state (for example, a clearance between the inner diameter of the guide portion 14 and the outer diameter of the lens holder 15 is about 10 to 20 μm). The guide portion 14 functions as a slide bearing, and the lens holder 15 is held in a state in which the lens holder 15 can smoothly slide along the optical axis direction of the light output from the laser diode 13 without play.

As described above, the case 11, the laser holder 1
2 and the guide part 14 become a fixing part (apparatus main body). The case 11, the laser holder 12, and the guide portion 14 may be formed integrally or in whole or in part.

Further, the laser holder 12 and the lens holder 1
The lens holder 15 is urged by the coil spring 17 in the direction away from the laser diode 13 along the optical axis direction.

A male screw is formed on the outer peripheral surface of the lens holder 15 on the light projecting lens 16 side, and a female screw is formed on the inner peripheral surface of the lens barrel 18 to be screwed with the male screw of the lens holder 15.
The lens barrel 18 is screwed to the lens holder 15. A lens barrel cover 20 is fitted on the outer peripheral surface of the lens barrel portion 18.
An anti-reflection plate 21 for preventing regular reflection is fixed near one end of the inner peripheral portion of the lens barrel 18. Lens barrel 1
The lens barrel holding portion 19 is fitted to the other end of the inner peripheral portion of the lens 8.

The case 11 is interposed between the end of the lens barrel cover 20 on the side of the laser diode 13 and the end of the lens barrel holding portion 19 on the side of the light emitting lens 16. The section 18 and the lens barrel holding section 19 are supported so as to be rotatable with respect to the case 11.

Therefore, by rotating the lens barrel cover 20, the lens barrel cover 20, the lens barrel portion 18, the lens barrel holding portion 19 and the antireflection plate 21 are integrally rotated, and the lens barrel cover 20, the lens barrel portion The rotation unit 18 and the lens barrel holding unit 19 are provided. The lens-barrel cover 20, the lens-barrel part 18, and the lens-barrel holding part 19 may form all or some of them integrally.

On the outer peripheral surface of the lens barrel holding portion 19, the lens barrel holding portion 1 is provided.
9, a plurality of locking portions 25 are formed in a gear shape at a constant pitch, each of the locking portions 25 has a substantially triangular cross section and a raised shape. , A substantially inverted triangular valley is formed. The shape and number of the locking portions 25 are not particularly limited to the illustrated example, and other shapes and numbers may be used.

A multistage cylindrical lock portion 22 is arranged on the side of the lens barrel holding portion 19, and both ends of the lock portion 22 are supported by the case 11 and an upper lid 26 fixed to the case 11. It is supported in a rotatable state.
Slots 24 are provided at both ends of the lock portion 22, and the tip of a screwdriver is inserted into the slit 24 to rotate the lock portion 22 around the arrow direction in the drawing, that is, the direction orthogonal to the optical axis direction. Can be.

In the middle portion of the lock portion 22, two convex portions 23 having a substantially triangular cross section are formed so as to protrude in one direction (downward in FIG. 3). 3 and 4 show a state in which the lens barrel holding unit 19, that is, the rotating unit is not locked by the lock unit 22. The shape and number of the protrusions 23 are not particularly limited to the illustrated example, and may be other shapes and numbers.

In the light emitting unit 2 of the photoelectric switch 1 configured as described above, the laser diode 13 is connected to the laser holder 1.
2, the guide portion 14 is fixed to the laser holder 12, and the lens holder 15 holding the light projecting lens 16 for receiving the light output from the laser diode 13 is the light output from the laser diode 13 by the guide portion 14. Are slidably supported in the optical axis direction.

At this time, the lens holder 1 is
5 is inserted in a highly accurate fitting state, so that there is no backlash in the direction orthogonal to the optical axis direction.
5, ie, the light projecting lens 16 can be slid in the optical axis direction with respect to the laser diode 13.

The lens barrel 18 screwed with the lens holder 15 is supported by the case 11 together with the lens barrel holder 19 and the lens barrel cover 20 so as to be rotatable about the optical axis direction. By rotating the tube cover 20, the lens holder 15 screwed to the lens barrel 18 can be moved in the optical axis direction.

At this time, since the lens barrel 18 rotates and the lens holder 15 slides in accordance with the rotation of the lens barrel 18, the lens holder 15, ie, the light projecting lens 16 moves in the optical axis direction without rotating. . Therefore, the light projecting lens 16 can be moved while maintaining the center position of the light projecting lens 16 in the optical axis direction of the light output from the laser diode 13 at a position adjusted with high accuracy at the time of assembly.

As a result, while maintaining the center position of the light projecting lens 16 with respect to the optical axis of the light output from the laser diode 13 with high precision, the light projecting lens 16 is moved with high precision in the optical axis direction with respect to the laser diode 13. Can be moved.

Since the lens holder 15 is urged in the optical axis direction of the light output from the laser diode 13 by the coil spring 17, the lens holder 15 and the lens barrel 1
It is possible to eliminate play in the optical axis direction at the screwing portion with the screw 8, and it is possible to more accurately slide and move in the optical axis direction. The biasing means is not particularly limited to the above-described coil spring, but may be another spring such as a plate spring or a disc spring, or an elastic member such as elastic rubber.

FIG. 5 shows the lens barrel holding unit 1 by the lock unit 22.
FIG. 6 is a partial cross-sectional view mainly showing a light emitting unit 2 of the photoelectric switch shown in FIG. 1 in a locked state where 9 is locked, and FIG. 6 is a partial view of the light emitting unit shown in FIG. It is sectional drawing.

When the user inserts a screwdriver into the slot 24 and rotates the lock portion 22 by 90 degrees, as shown in FIGS. 5 and 6, the convex portion 23 of the lock portion 22 It is interposed between the locking portions 25. Even if the user tries to rotate the lens barrel cover 20 in this state, the locking part 25 of the lens barrel holding part 19 comes into contact with the convex part 23 of the lock part 22, and the lens barrel cover 20 does not rotate. Tube holder 19
Is locked, and the position of the light projecting lens 16 with respect to the laser diode 13 is fixed.

Here, in the locked state shown in FIGS. 5 and 6, the protrusion 23 of the lock portion 22 and the locking portion 2 of the lens barrel holding portion 19
The cross-sectional shape of the lens 5 is set so that a predetermined clearance is formed in the rotation direction of the lens-barrel holding portion 19. Therefore, when the convex portion 23 is interposed exactly in the middle between the locking portions 25, the convex portion 23 and the locking portion 25 do not abut. As a result, unnecessary stress is not transmitted from the lock unit 22 to the light projecting lens 16 via the lens barrel holding unit 19, and the lens barrel holding unit 19 does not rotate. Projection lens 1 for 13
The position of the projection lens 16 is not changed at all, and is highly accurate.
With the position adjusted, the projection lens 16 can be locked as it is.

When the position of the locking portion 25 is slightly shifted and the projection 23 is interposed between the locking portions 25 while the projection 23 and the locking portion 25 are in contact with each other, the lens barrel holding Since the portion 19 has no member other than the lock portion 22 to restrict its rotation,
Unnecessary stress from the convex portion 23 can be released by slightly rotating the lens barrel holding portion 19. Therefore, also in this case, unnecessary stress is not transmitted to the light projecting lens 16 from the lock unit 22 via the lens barrel holding unit 19. In this case, the lens barrel holder 19 rotates slightly, but the amount of movement in the optical axis direction with respect to the rotation amount of the lens barrel holder 19 is very small.
The position of the light projecting lens 16 with respect to is hardly changed, and the light projecting lens 16 can be locked with the position of the light projecting lens 16 adjusted with high precision.

As described above, in this embodiment, the focal length can be adjusted while maintaining the center position of the light projecting lens 16 with respect to the optical axis of the light output from the laser diode 13 with high accuracy. Further, since the position of the light projecting lens 16 with respect to the laser diode 13 hardly changes before and after the locking operation after the focus adjustment, the light projecting lens 16 can be locked without changing the spot. Further, since the light projecting lens 16 is locked after the lock, the spot does not change during the detection of the object. Therefore, the operation of adjusting the focal length, the operation of locking, and the operation of detecting are facilitated, and the presence or absence of a desired object can be easily detected in a short time.

In the present embodiment, the lock mechanism 22 is used as a lock mechanism that rotates about a direction orthogonal to the optical axis direction as a center of rotation. A lock portion interposed between the portions 25 may be used. Although the locking portion 25 is provided on the outer peripheral surface of the lens barrel holding portion 19, the locking portion is formed on the inner peripheral surface of the lens barrel holding portion 19, and the locking portion interposed between the locking portions is provided. May be used.

In the above description, the photoelectric switch has been described as an example. However, the optical device to which the present invention is applied is not particularly limited to the above photoelectric switch as long as it emits light. It can be applied to any type of photoelectric switch, such as a type or transmission type, a built-in amplifier type or an amplifier separated type, a separation optical system that separates the projecting optical system and the receiving optical system, or a coaxial optical system using a beam splitter etc. Also, the present invention can be similarly applied to other optical devices such as a photoelectric sensor and an optical displacement meter for measuring a distance to an object and the like, a color discriminating sensor for identifying color shading, and the like. Can be obtained. Further, although a laser diode is used as the light emitting unit, an LED or the like may be used.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a photoelectric switch according to an embodiment of the present invention as viewed from one direction.

FIG. 2 is an external perspective view of the photoelectric switch of FIG. 1 as viewed from another direction.

FIG. 3 is a partial cross-sectional view mainly showing a light projecting portion of the photoelectric switch shown in FIG. 1;

FIG. 4 is a partial cross-sectional view of the light projecting unit shown in FIG. 3 as viewed from the back.

5 is a partial cross-sectional view mainly showing a light projecting portion of the photoelectric switch shown in FIG. 1 in a locked state in which the lens barrel holding portion is locked by the lock portion.

FIG. 6 is a partial sectional view of the light projecting unit shown in FIG. 5 as viewed from the back.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoelectric switch 2 light emitting part 3 light receiving part 4 display part 11 case 12 laser holder 13 laser diode 14 guide part 15 lens holder 16 light emitting lens 17 coil spring 18 lens barrel part 19 lens barrel holding part 20 lens barrel cover 21 anti-reflection Plate 22 Locking part 23 Convex part 24 Slit 25 Locking part 26 Upper lid

Claims (3)

[Claims] 1. An optical device for projecting light, comprising: a light emitting unit fixed to a device main body and outputting light; a lens receiving light output from the light emitting unit; and holding the lens. A lens holding portion, a support portion fixed to the device main body, and supporting the lens holding portion in a state of being slidable in the optical axis direction of the light output from the light emitting portion; An optical device, comprising: a rotating unit supported and screwed with the lens holding unit. 2. The optical device according to claim 1, further comprising an urging unit that urges the lens holding unit in an optical axis direction of the light output from the light emitting unit. 3. The rotating part includes a plurality of locking parts formed along a rotating direction of the rotating part, and the rotating part moves in the optical axis direction of light output from the light emitting part or is in the optical axis direction. 2. The lock device according to claim 1, further comprising a lock portion interposed between adjacent lock portions of the plurality of lock portions to lock the rotation of the rotary portion by rotating about the intersecting direction as a rotation center. Or the optical device according to 2.