JPS626117A - Rotary encoder - Google Patents

Abstract

PURPOSE:To shorten substantially a pitch of a slit and to increase the number of pulses, by constituting the titled rotary encoder so that an array pitch of a slit of a rotary disk and an array pitch of a slit of a fixed slit plate are different from each other. CONSTITUTION:On a rotary disk 1, N pieces of slits 5 are formed at an equal interval of N pieces/round in the peripheral direction in its outside peripheral edge. On a fixed slit plate 2, one piece - several pieces of slits 6 are formed at an equal interval of NXn/m pieces/round in the peripheral direction of a circle for forming a sector. In this case, the slits 5 and 6 are constituted so as to be placed in the same radial position, when the rotary disk 1 and the fixed slit plate 2 have been placed so as to be opposed to each other, and also an array pitch of the slit 5 of the rotary disk 1 and an array pitch of the slit 6 of the fixed slit plate 2 are made different from each other. In this way, the pitch of the slits is shortened substantially and the number of pulses can be increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has a disk configured by arranging a plurality of radially extending slits along the circumference, and the disk is sandwiched between the disks. A light emitting element and a light receiving element are placed in opposing positions,
By rotating the disk, the light from the light emitting element is temporally intermittent through multiple slits, and the intermittent light is received by the light receiving element, thereby generating a pulse signal according to the rotation speed of the disk. The present invention relates to a rotary encoder as described above.

[Summary of the Disclosure] The present invention provides two rotating disks having a slit row consisting of slits arranged at equal intervals in the circumferential direction, and a rotary disk disposed facing the rotating disk and having a row of slits arranged at equal intervals in the circumferential direction. In a rotary encoder that has a fixed slit plate having a row of slits, the light from the light emitting element is incident on the light receiving element through the rotating disk and the fixed slit plate, and the output is taken out from the light receiving element. and a fixed three.

This invention discloses a technique that can substantially shorten the slit pitch and increase the number of pulses by making the pitch of the slits on the top plate different from each other.

This summary is provided solely for the purpose of quickly accessing the technical content of the present invention, and does not have any influence on the technical scope of the present invention or the interpretation of rights. be.

[Prior Art] Conventionally, in this type of rotary encoder, as described above, a fixed slit in which a plurality of slits are arranged at the same angular intervals as the slits faces a rotating disk in which slits are formed all around the circumference. Place the board,
Of the light from the light emitting element, only the light that has passed through the slit of the rotating disk and further passed through the slit of the fixed slit plate is made to enter the light receiving element. Here, if the angular interval between the slits of the rotating disk is N (I/389°), then N pulses are extracted from the light receiving element per one rotation of the rotating disk.

Note that the light-receiving element generally has a light-receiving surface that can receive light from several slits.
The amplitude of the output waveform from the light receiving element is determined according to the number of light receiving elements.

In such a rotary encoder, the higher the number of pulses generated per rotation, the more accurate rotation speed detection can be performed, so it is desired to increase the number of slits in the disk per rotation as much as possible. There is. Among such disks, those with high pulse density are manufactured by etching a metal film deposited on a glass disk, but the manufacturing process is complicated and the product is expensive. On the other hand, cheaper rotating disks are formed by punching metal plates, etching metal plates, or plating, respectively.

There is a manufacturing limit to the slit density, and even if a plating method suitable for forming high-density slits is used, the slit pitch will be 1501 L or more, and therefore the number of slits will be at most 7 wood/■■. Therefore, at present, it is not possible to achieve higher density and therefore higher pulses.

[Problems to be Solved] Therefore, an object of the present invention is to provide a rotary encoder that can realize high pulses without increasing the number of slits.

[Means for Solving the Problem] In order to achieve such an object, a first aspect of the present invention provides a rotating disk having a slit row consisting of slits arranged at equal intervals in one circumferential direction, and a rotating disk. It has a fixed slit plate having a slit row consisting of slits arranged at equal intervals in the circumferential direction, and the light from the light emitting element is incident on the light receiving element through the rotating disk and the fixed slit plate. In the rotary encoder which extracts an output from a light receiving element, the rotary encoder is characterized in that the arrangement pitch of the slits on the rotating disk and the arrangement pitch of the slits on the fixed slit plate are made different from each other.

In a second embodiment of the present invention, there is provided a rotating disk having a slit row consisting of slits arranged at equal intervals in the circumferential direction, and a rotating disk disposed opposite to the rotating disk and having a row of slits arranged at equal intervals in the circumferential direction. In a rotary encoder that has a fixed slit plate with a row of slits, the light from one light emitting element is incident on the light receiving element through the rotating disk and the fixed slit plate, and the output is taken out from the light receiving element. The present invention is characterized in that the slit arrangement pitch of the fixed slit plate and the fixed slit plate are different from each other, and a plurality of slit rows are arranged concentrically on either the one-rotation disk or the fixed slit plate.

In a third aspect of the present invention, a rotating disk having a slit row consisting of slits arranged at equal intervals in the circumferential direction;
A slit consisting of slits arranged at equal intervals in the circumferential direction.
In a rotary encoder that has a light receiving means having a light receiving part corresponding to two rows of lights and a light source, the light from the light source is made incident on the light receiving part via a rotating disk, and the output is taken out from the light receiving lambda element. It is characterized in that the arrangement pitch of the slits and the arrangement pitch of the slits in the light receiving portion are made different from each other.

In a fourth aspect of the present invention, a rotating disk having a slit row consisting of slits arranged at equal intervals in one circumferential direction,
It has a light receiving means having a light receiving part corresponding to a slit row consisting of slits arranged at equal intervals in the circumferential direction, and a light source, the light from the light source is made incident on the light receiving part via a rotating disk, and the light receiving element In a rotary encoder that takes out output from The slits are arranged in rows, and the plurality of slit rows are shifted from each other.

[Function] According to the present invention, the pitch of the slits in the three and three parts of the rotating disk and the pitch of the slits in the fixed slit plate or the slit pattern on the light-receiving surface are made different from each other, thereby substantially shortening the pitch of the slits. [Embodiment] The present invention will be described in detail below with reference to one drawing.

FIG. 1 shows an outline of an embodiment of the rotary encoder of the present invention, where 1 is a disk-shaped rotating disk, 2 is a sector-shaped fixed slit plate, 3 is a light emitting element as a light source, and 4 is a light emitting element from a light source l. The 0-rotation disk l, which is a light receiving element that receives light via the rotating disk 1 and the fixed slit plate 2, has a
N slits 5 are formed on the outer periphery at equal intervals of N slits/circumference in the circumferential direction. The fixed slit plate 2 has N x n/m wood/circumference (however, m
, n is a relatively prime integer, m″41.n″ql and m=n±1) from one to several slits 6 at equal intervals.
form. Here, the slits 5 and 6 are arranged at the same radial position when the rotating disk 1 and the fixed slit plate 2 are arranged facing each other.

Here, the relationship between the slits 5 and 6 will be explained in detail with reference to FIG. 2 for the case where m=3°, n=2°, and N=500.

In FIG. 2, (A) and (C) show the relative positional relationship between the slit 6 of the fixed slit plate and the slit 5 of the rotating disk, and (B) shows the generation timing of the encoder output pulse P over time T. In this case,
The output pulses P are generated simultaneously every other time when viewed from the fixed slit plate side, and are 2 x 500 = per rotation.
Generates 1000 pulses.

Here, when obtaining a pulse with a duty ratio of 1:1, if the slit width of each slit is 254 m+ and the width of the light-shielding portion of the disk is 75 m+, then this corresponds to the pitch of 3 and 7 in one row. It can be seen that the actual pitch is 50 μI.

Generally, an output pulse P is generated every nth pulse, so
Since nXN pulses are generated per rotation, it is possible to increase the number of pulses.

In addition, in the -L example, m is set to m=nfl, but the reason is that if m is set to a prime number other than nthl, the pitch of one of the slits, for example, the slit of the fixed slit plate, becomes too wide, and the light receiving element This is because the light-receiving surface cannot be made smaller. Therefore, it is preferable to set m=n±1 and shorten the pitch of the slits.

FIG. 3 shows another embodiment of the present invention, in which a mask with a slit pattern corresponding to the slits 6 shown in the first diagram is placed in close contact with the light-receiving surface 12 of the light-receiving element 11 itself. do. Alternatively, a light receiving device may be provided in which minute light receiving elements are integrated and arranged in correspondence with this slit pattern. In this case, a separate fixed slit plate can be omitted.

Figure f:tS4 shows yet another embodiment of the present invention, in which two slit rows are formed in the rotary disk 1, with slits 13 and 14 doubly arranged in a concentric circle. These two slit rows are equivalent to a double array of slit rows consisting of slits 7) 15 and 1B shown by solid lines and broken lines, as shown in FIG. 5, and according to this, the slit pitch can be adjusted. The slit pitch can be substantially shortened without shortening. Note that the number of such slit arrays is not limited to two, but can generally be arranged in n-fold. Furthermore, the slit array of this multiple array is
Of course, the present invention is not limited to the case where it is provided on the rotating disk l, but may also be applied to a slit formed on a fixed slit plate or a light receiving element.

[Effects of the Invention] As is clear from the following, according to the present invention, by making the pitch of the slits on the rotating disk different from the pitch of the slits in the slit pattern on the fixed slit plate or the light-receiving surface, It is possible to obtain a pulse output with an increased number of pulses corresponding to a shortened pitch of the slits.

In the present invention, the slit width is made smaller than the width of the light shielding part, but a resist pattern is formed on a thin metal plate, a metal layer is formed by plating on the thin metal plate through the pattern, and then the thin metal plate and resist pattern are removed. When forming slits using a plating method, although the minimum value of the light-shielding portion is limited, it is easy to narrow the width of the slit between the light-shielding portions formed by the growth of plating.

Therefore, the encoder of the present invention can be suitably manufactured using such a plating method.

Furthermore, in the present invention, the pitch of the slits on the rotating disk and the pitch of the slits in the slit pattern of the fixed slit plate or the light-receiving surface 1 are made different from each other, and the slits of either one are arranged in multiple concentric circles. Accordingly, it is possible to obtain an encoder output with an increased number of pulses corresponding to a substantially shorter slit pitch without narrowing the slit interval.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of an embodiment of an unfired IJ, and FIG. 2 is an explanatory diagram of its operation. FIG. 3 is a perspective view showing a light receiving element in another embodiment of the invention, FIG. 4 is a plan view showing a rotating disk in still another embodiment of the invention, and FIG. 5 is an explanatory diagram of its operation. DESCRIPTION OF SYMBOLS 1... Rotating disk 2... Rotating slit plate, 3... Light emitting element, 4... Light receiving element, 5... Slit. 6...Slit. ll... Light receiving element. 12... Light receiving surface with slit pattern, 13.14
...Double array slit, 15.18...Slit.

Claims (1)

[Scope of Claims] 1) A rotating disk having a slit row consisting of slits arranged at equal intervals in the circumferential direction, and a rotating disk having slits arranged at equal intervals in the circumferential direction and disposed opposite to the rotating disk. In the rotary encoder, the rotary encoder has a fixed slit plate having a row of slits, and allows light from a light emitting element to enter a light receiving element through the rotating disk and the fixed slit plate, and extracting an output from the light receiving element. A rotary encoder characterized in that the arrangement pitch of the slits of the fixed slit plate and the arrangement pitch of the slits of the fixed slit plate are different from each other. 2) A rotating disk having a slit row consisting of slits arranged at equal intervals in the circumferential direction, and a stationary device disposed opposite to the rotating disk and having a slit row consisting of slits arranged at equal intervals in the circumferential direction. A rotary encoder that has a slit plate and makes light from a light emitting element enter a light receiving element through the rotating disk and the fixed slit plate, and extracts an output from the light receiving element, and the arrangement pitch of the slits of the rotating disk and the fixed slit plate are as follows: A rotary encoder characterized in that the slits of the slit plates are arranged at different pitches, and a plurality of slit rows are arranged concentrically on one of the rotating disk and the fixed slit plate. 3) A rotating disk having a slit row consisting of slits arranged at equal intervals in the circumferential direction, a light receiving means having a light receiving portion corresponding to the slit row consisting of slits arranged at equal intervals in the circumferential direction, and a light source. and making light from the light source enter the light receiving portion via the rotating disk,
A rotary encoder that extracts an output from the light-receiving element, wherein the arrangement pitch of the slits in the rotating disk and the arrangement pitch of the slits in the light-receiving portion are different from each other. 4) A rotating disk having a slit row consisting of slits arranged at equal intervals in the circumferential direction, a light receiving means having a light receiving portion corresponding to the slit row consisting of slits arranged at equal intervals in the circumferential direction, and a light source. and making light from the light source enter the light receiving portion via the rotating disk,
In the rotary encoder that extracts an output from the light receiving element, the arrangement pitch of the slits of the rotating disk and the arrangement pitch of the slits of the light receiving part are made different from each other, and either the rotating disk or the fixed slit plate has the above-mentioned A rotary encoder characterized in that a plurality of slit rows are arranged concentrically and the plurality of slit rows are shifted from each other.