JPH06100482B2 - Rotary Encoder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has a disk having a plurality of slits extending in the radial direction arranged along the circumference, and sandwiching the disk. Arrange the light emitting element and the light receiving element at the facing position,
By rotating the disc, the light from the light emitting element is intermittently timed through a plurality of slits, and the intermittent light is received by the light receiving element to generate a pulse signal according to the number of revolutions of the disk. The present invention relates to a rotary encoder.

[Summary of Disclosure] The present invention relates to a rotating disk having a slit row composed of slits arranged at equal intervals in the circumferential direction and a slit arranged facing the rotating disk and arranged at equal intervals in the circumferential direction. In a rotary encoder that has a fixed slit plate having a slit array, 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 extracted from the light receiving element, One of the slit rows is concentrically arranged in a plurality of rows, and the plurality of slit rows are offset from each other, so that the slit rows are simply concentrically arranged in a multiple array without reducing the slit spacing. It is possible to obtain pulse output with an increased number of pulses, which is equivalent to shortening the slit pitch. The technology that can be performed is disclosed.

Note that this outline is provided only for quick access to the technical contents of the present invention, and has no influence on the technical scope and the interpretation of rights of the present invention. is there.

[Prior Art] Conventionally, in this type of rotary encoder, a fixed slit, which is opposed to a rotary disc having slits formed all around as described above, is provided with a plurality of slits at the same angular intervals as those of the slits. Place the boards,
Of the light from the light emitting element, only the light that passes through the slit of the rotating disk and further passes through the slit of the fixed slit plate is made incident on the light receiving element. Here, if the angular spacing of the slits of the rotating disk is N / 360 °,
From the light receiving element, N pulses are taken out per one rotation of the rotating disk.

The light receiving element generally has a light receiving surface capable of receiving light from several slits, and the amplitude of the output waveform from the light receiving element is determined according to the number of slits as the light receiving target.

In such a rotary encoder, the more the number of pulses generated per rotation, the more accurately the rotation number can be detected. Therefore, it is desired to increase the number of slits of the rotary disc as much as possible. There is. Among such discs, those of high pulse density are produced by etching a metal film deposited on a glass disc, but the production process is complicated and the product is expensive. On the other hand, cheaper rotary disks are formed by punching a metal plate, etching a metal plate, or plating, but each has a slit density limit in manufacturing, and is suitable for high-density slit formation. Even if the method is used, the pitch of the slits is 150 μm or more, and therefore the number of slits is at most 7 / mm, and it is the current situation that higher density and hence higher pulse cannot be expected.

[Problem to be Solved] Therefore, an object of the present invention is to provide a rotary encoder capable of realizing a high pulse without increasing the number of slits.

[Means for Solving Problems] In the present invention, in order to achieve such an object, a device is added to a pattern of slits formed on the rotating disk, the fixed slit plate, or the light receiving element.

That is, the present invention is directed to a rotary disc having a slit row composed of slits arranged at equal intervals in the circumferential direction and a slit row made up of slits arranged to face the rotary disk and arranged at equal intervals in the circumferential direction. Having a fixed slit plate having, and making light from the light emitting element incident on one light receiving element via the rotating disk and the fixed slit plate,
In a rotary encoder that takes out the output from the light receiving element, slit rows are concentrically arranged on one of the rotating disk and the fixed slit plate, the slit rows are displaced from each other, and the rotating disk is plated. It is characterized by being formed.

According to another aspect of the present invention, a rotary disk having a slit row composed of slits arranged at equal intervals in the circumferential direction, and a light receiving portion corresponding to the slit row made of slits arranged at equal intervals in the circumferential direction. In a rotary encoder having one light receiving means and a light source, the light from the light source is incident on the light receiving portion through the rotating disc and the output is taken out from the light receiving element, one of the rotating disc and the light receiving portion is provided. A plurality of slit rows are concentrically arranged, and the plurality of slit rows are offset from each other.

[Operation] According to the present invention, the number of pulses corresponding to a substantial reduction in the pitch of the slits can be increased by simply arranging the slit rows in a concentric multiple manner without narrowing the slit spacing. A pulse output can be obtained.

EXAMPLES The present invention will be described in detail below with reference to the drawings.

1 and 2 show a part of the rotary disk 10 and a fixed slit plate 20, respectively, in an embodiment of the encoder of the present invention. The rotating disk 10 is formed with outer slits 11 arranged at equal intervals along the circumference near the outer edge thereof at a pitch P. Inside this outer slit 11,
The inner slits 12 are formed at equal intervals along the circumference at a pitch P'with a slight gap. Here, since the slits 11 and 12 are formed near the outer edge of the disk 10 and the length in the longitudinal direction of the slit is shorter than the radius of the disk 10, it can be regarded as P = P '.

As shown in FIG. 2, the fixed slit plate 20 is a rotating disk.
The fixed slit plate 20 is formed with one to several slits 21 arranged at equal intervals along the circumference of the circumference with a circumferential portion having substantially the same radius as 10.

The light receiving element generates a photoelectric conversion output according to the light incident from the light emitting element after passing through the slits of the rotating disk 10 and the fixed slit plate 20. Here, it is assumed that the light receiving surface of the light receiving element has an area including a predetermined number of slits among the slits 21 of the fixed slit plate 20. The larger the predetermined number, the larger the photoelectric conversion output, but the number of pulses of the photoelectric conversion output pulse / rotation becomes a value according to the pitch determined by the number of slits 11 and 12 as described later. .

Here, for each pitch P of the slits 11 and 12, the distance between the slits 11 and 11 is y, and the deviation between the slits 11 and 12, that is, the substantial arrangement pitch of the slits in the present invention is x. . The relationship between these quantities P, x, y will be described with reference to FIG. 3 in the case where the duty ratio of the pulse output is 1: 1.

FIG. 3A shows the slits 13 in a single row with the pitch P by a solid line. In the present invention, two rows of slits 11 and 12 shown in FIGS. 3 (B) and 3 (C) are arranged. In that case, FIG. 3 (A) is used.
As shown in, the solid line slit 13 between the broken line slit
Substantially corresponds to one slit row which is half the pitch where 14 is inserted. Thus, the pitch of the slit row when the broken line slit 14 is inserted in the middle of the solid line slit 13 is P / 2, and this value is equal to x.

That is, Is. Furthermore, Than, Therefore, from this formula And therefore Becomes In this case, a pulse output having a duty ratio of 1: 1 as shown in FIG. 3D is taken out after waveform shaping.
Here, when the pitch P of the slits in each row is 100 μm, the substantial pitch x is 50 μm. Each slit 11,1
The slit width of 2 is 25 μm. If P = 150 μm and the slit width of each slit 11 and 12 is 37.5 μm, x
= 75 μm.

Although FIG. 3 illustrates the case where the duty ratio is 1: 1, the duty ratio is not limited to 1: 1 and the pulse width of any desired duty ratio can be obtained by appropriately changing the slit widths of the slits 11 and 12. Can be generated.

FIG. 4 shows another embodiment of the present invention, in which three rows of slits 11, 12 and 15 are concentrically arranged on the rotary disk 10. In this case, FIG. 5 (A), (B),
Since the slits 11, 12, 15 are arranged as shown by solid lines in (C), the slits 11, 16, 17, 11, are substantially arranged as shown by solid lines and broken lines in FIG. 5 (A). 16,17, ... arranged one
Equivalent to a row of slits, the effective pitch x is Becomes If P = 150 μm and the slit width is 25 μm, x = 50 μm. That is, pitch 150 μm
With the slits, slits with a pitch of 50 μm are formed substantially.

In the present invention, the slit rows to be multiply arranged are not limited to the above-mentioned two rows or three rows, but n rows (n is 2
The above-mentioned positive integer), and in that case, the slits arranged in n rows substantially correspond to one slit row having the pitch x. Here, x = P / n = 2y / (2n-1). That is, according to the present invention, by arranging n slit rows in which N slits are formed per revolution, encoder output pulses of N × n pulses / rotation can be obtained. In other words, as the number of slit rows is increased, the number of pulses per one rotation can be increased without narrowing the slit interval.

Here, since the slit width is P−Y, slit width = P−Y = P− (2n−1) × P / (2n) = P / (2n).

6 and 7 show still another embodiment of the present invention, in which one row of slits 18 are arranged on the rotary disk 10 along the circumference, but one on each fixed slit plate 20. A slit array consisting of a few slits 22 and 23 is concentrically arranged and arranged at equal intervals along the circumference. The slits 22 and 23 are displaced from each other by a slight distance.
Also in this example, in the same manner as shown in FIG.
The slit pitch of the fixed slit plate 20 is x, and therefore is substantially P / 2. As a result, even in this example,
As shown in FIG. 3 (D), an output pulse having a duty ratio of 1: 1 is extracted corresponding to the slit pitch x.

In the above example, instead of providing the fixed slit plate 20, minute light receiving elements are integrally integrated and arranged corresponding to the pattern of the double slit arrangement, or a slit pattern is formed so as to correspond to the slit pattern on the light receiving surface. Of course, it is also possible to arrange a mask having the above in close contact. In this case, it is not necessary to separately provide the fixed slit plate.

[Effects of the Invention] As is apparent from the above, according to the present invention, the pitch of the slits is substantially shortened by simply arranging the slit rows in a concentric multiple manner without narrowing the slit intervals. A pulse output with an increased number of pulses can be obtained.

In the present invention, the slit width is made smaller than the width of the light shielding portion, but a resist pattern is formed on the metal thin plate, and a metal layer is formed by plating on the metal thin plate through the pattern,
Then, when the slit is formed by using the plating method of removing the metal thin plate and the resist pattern, the minimum value of the light shielding part is limited, but the width of the slit between the light shielding parts formed by the growth of the plating is narrowed. Easy to do. Therefore, the encoder of the present invention can be manufactured only by using the plating method.

[Brief description of drawings]

FIG. 1 is a plan view showing a rotary disk in one embodiment of the present invention, FIG. 2 is a plan view showing a fixed slit plate, FIG. 3 is an explanatory view of its operation, and FIG. 4 is another embodiment of the present invention. FIG. 5 is a plan view showing a rotary disc in an example, FIG. 5 is an operation explanatory view thereof, FIG. 6 is a plan view showing a rotary disc in still another embodiment of the present invention, and FIG. 7 is a plan view showing a fixed slit plate. Is. 10 …… Rotating disk, 11 ～ 18 …… Slit, 20 …… Fixed slit plate, 21 ～ 23 …… Slit.

Claims (2)

[Claims] 1. A rotary disk having a slit row composed of slits arranged at equal intervals in the circumferential direction, and a slit row made of slits arranged so as to face the rotary disk and arranged at equal intervals in the circumferential direction. In a rotary encoder having a fixed slit plate having, a light from the light emitting element is incident on the light receiving element through the rotating disk and the fixed slit plate, and an output is extracted from the light receiving element, the light receiving element is one and The slit rows are arranged concentrically in n rows (an integer of n ≧ 2) on one of the rotary disk and the fixed slit plate, and the slit rows of the n rows are offset from each other, and the width of the slits is the slit pitch. The rotary encoder is characterized in that it is approximately P / (2n) when P is. 2. A rotating disk having a slit row composed of slits arranged at equal intervals in the circumferential direction, and a light receiving means having a light receiving portion corresponding to the slit row composed of slits arranged at equal intervals in the circumferential direction. A rotary encoder having a light source, which allows light from the light source to enter the light receiving portion through the rotating disk and extracts an output from the light receiving element, wherein the number of the light receiving portion is one and the rotating disk and the In one of the light receiving portions, the slit rows are concentrically arranged in n rows (n ≧ 2 is an integer), the slit rows of n rows are displaced from each other, and the width of the slits has a slit pitch of P. The rotary encoder is characterized in that it is approximately P / (2n).