JP2567907B2 - Linear encoder - Google Patents

Description

The present invention relates to a linear encoder, and more particularly to a high resolution linear encoder using light.

[Technical environment]

In recent years, linear encoders using light tend to have higher resolution and wider dynamics as optical semiconductor technology advances, and have become increasingly important as means for detecting speed and position of mechatronics equipment.

[Common technology]

Generally, a linear encoder using light includes a fixed body and a movable body.

This linear encoder encodes the movement of the movable body with respect to the fixed body by the number of blinks of light.

That is, the structure is such that light is blocked and transmitted every time the movable body moves a certain distance.

[Conventional technology]

The conventional linear encoder includes (A) first and second mirrors arranged to face each other, (B) a guide rail arranged in parallel to the first and second mirrors, and (C) along a front guide rail. A light-receiving element fixed to the slide body so as to face the first mirror, and (E) a light-emitting unit that supplies a light beam for measurement to the mirror. Composed of.

Next, a conventional linear encoder will be described in detail with reference to the drawings.

FIG. 3 is a perspective view showing an example of a conventional linear encoder.

The linear encoder shown in FIG. 3 slides along (A) the mirrors 1 and 2 facing each other, (B) the guide rails 3 arranged parallel to the mirrors 1 and 2, and (C) the guide rails 3. A sliding body 4, (D) a light receiving element 5 fixed to the sliding body 4 so as to face the mirror 1, and (E) a light emitting section 7 for supplying a measuring light beam to the mirror 2. It

 A laser light source or the like is used for the light emitting unit 7.

4 (a) and 4 (b) are operation explanatory views of the linear encoder shown in FIG.

As shown in FIG. 4A, the light beam a is incident from the right end, is reflected N times between the mirrors 1 and 2, and is incident on the light receiving element 5.

FIG. 4 (b) shows a case where the sliding body 4 has moved to the left.
In this case, the light beam is reflected N + 2 times and enters the light receiving element 5.

Therefore, the position detection resolution of this linear encoder is
It is equal to the distance d between adjacent light reflection points on the same mirror surface.

[Problems to be Solved by the Invention]

The conventional linear encoder described above has a resolution of distance d.
It had the drawback that it could not be made smaller.

[Means for solving the problem]

The linear encoder of the present invention comprises: (A) first and second mirrors arranged to face each other, (B) guide rails arranged in parallel to the first and second mirrors, and (C) the first and second mirrors. A slide body that slides along the guide rail in the center of a second mirror, (D) First and second light receiving elements fixed to the slide body so as to face the first and second mirrors And (E) a light emitting unit that supplies a light beam for measurement to the mirror.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

 FIG. 1 is a perspective view showing an embodiment of the present invention.

The linear encoder shown in FIG. 1 includes (A) mirrors 1 and 2 arranged to face each other, (B) guide rails 3 arranged parallel to the mirrors 1 and 2, and (C) guides the centers of the mirrors 1 and 2. A sliding body 4 sliding along the rail 3, (D) light receiving elements 5 and 6 fixed to the sliding body 4 so as to face the mirrors 1 and 2, and (E) supplying a light beam for measurement to the mirror 2 And a light emitting section 7 that operates.

2 (a) and 2 (b) are operation explanatory views of the linear encoder shown in FIG.

As shown in FIG. 2A, the light beam a is incident from the right end, is reflected N times between the mirrors 1 and 2, and is incident on the light receiving element 5.

FIG. 2B shows the case where the sliding body 4 has moved to the left.
In this case, the light beam is reflected N + 1 times and enters the light receiving element 6 on the lower surface of the light receiving element 5.

Therefore, the position detection resolution of this linear encoder is
Equal to the distance d / 2 between adjacent light reflection points on the same mirror surface.

〔The invention's effect〕

The linear encoder of the present invention has an effect that the resolution can be made equal to or less than the interval between the adjacent light reflection points on the same mirror surface by adding the light receiving element to the lower surface of the sliding body.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIGS. 2 (a) and 2 (b) are operation explanatory views of the linear encoder shown in FIG. 1, and FIG. 4 (a) and 4 (b) are operation explanatory views of the linear encoder shown in FIG. 1,2 …… Mirror, 3 …… Guide rail, 4 …… Sliding body, 5,6…
… Light receiving element, 7… Light emitting part. a: light beam, d: distance.

Claims (1)

(57) [Claims] 1. (A) First and second mirrors arranged to face each other, (B) Guide rails arranged in parallel to the first and second mirrors, (C) The first and second mirrors (D) first and second light receiving elements fixed to the sliding body so as to face the first and second mirrors; E) A light-emitting unit that supplies a light beam for measurement to the mirror, and a linear encoder.