JPS5845510A - Rotary encoder - Google Patents

Abstract

PURPOSE:To simplify the processing circuit of a sensor, by setting the outside shape of a shielding plate so that the rotation angle and the quantity of light transmitted through a slit have a linear relation. CONSTITUTION:An encoder 4 is attached to a rotating material to change the quantity of light transmitted through a slit 2. A length (r) from a center C of the encoder 4 to the circumferential edge of the encoder 4 is set to satisfy r=atheta+b ((a) and (b) are constants, and anot equal to 0 and b>=0 are true, and theta is the rotation angle from the reference line). Consequently, the rotation angle of the rotating material is detected by the quantity of light transmitted through the slit 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary encoder suitable for application to an optical information processing device that processes information such as precise positioning of a detected object such as a motor shaft.

Conventionally, there are optical encoders that use light as the information medium for encoders that convert analog quantities into digital quantities, but since the code itself generates a digital signal, its accuracy depends on the size of the slit that holds the code. depends on. Therefore, in order to improve accuracy, the code must be made densely on the encoder, which is disadvantageous because processing costs increase.

Furthermore, in the case of an absolute value type encoder, the slit itself that indicates one code becomes large, and it is necessary to use many sensors to read the complicated absolute value code, resulting in a complicated structure. In an incremental encoder, only one light beam passes through the coded slit and is output as a signal, so in order to obtain position and velocity information, two sensors and two sensors are required to process the signals output from this sensor. Since the position and velocity cannot be detected from the signal itself, a special processing circuit such as signal synthesis is required.

In view of these points, the present invention provides a rotary encoder for optical information processing equipment in which the encoder can be easily processed, high-density information can be obtained to improve accuracy, and various output information can be obtained with a simple processing circuit. The main purpose is to propose.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIGS. 1A and 1B are diagrams showing an example of the rotary encoder of the present invention. 4 is a rotary encoder attached to an object to be detected such as a motor with equal axes. A reference line extending in the circumferential direction from the shaft center C! Based on this, the distance r from the axis center C to the circumferential edge of the encoder 4 is set to have a linear relationship expressed by the following equation.

r=aθ + b・・・・・・・・・・・・・・・
(1) (a, b are constants, a\o, b≧0, θ is the rotation angle from the reference line l) FIG. 2 is a block diagram showing an example of an optical information processing device. The amount of light from the light emitting section 6 is transmitted to the light receiving section 7. The light emitting section 6 uses a filament lamp or an infrared LED, and the light receiving section 7 uses a phototransistor or a photodiode. A signal from the light receiving section 7 is supplied via an amplifier 8 to a position signal output terminal 9, and is also supplied via a differentiator 10 to a speed signal output terminal 11. Furthermore, the output from the differentiator 10 is passed through a sign detector 12 to a moving direction signal output terminal 13.
is supplied to As shown in FIGS. 2 and 3, between the light emitting section 6 and the light receiving section 7, the slit 2 is provided on the light emitting section 6 side, and the above-mentioned encoder 4 is provided on the light receiving section 7 side so as to be in contact with each other. 'wood. In this case, as for the amount of light from the light emitting section 6, the larger the distance r from the center of the encoder dot to the peripheral edge, the smaller the amount of light detected by the light receiving section 7, and the smaller the distance r, the larger the amount of light. Therefore, based on equation (1), the change in the amount of light to the light receiving section 7 is proportional to the rotation angle θ of the encoder 40.

That is, L=a'θ + b' ・・・・・・・・・・・・
・・・・・・(2) (al, b' are constants, a\Q, b≧
0). Therefore, the position signal output terminal 9 represents the rotation angle of the encoder 4, that is, the position of the object moved by the motor or the like to which the encoder 4 is attached. Further, at the speed signal output terminal 11, a signal from a differentiator 10t (θ=fωdt, t is time, ω is angular velocity) is obtained. Since this signal has the dimension of angular velocity, the velocity of the object is displayed. Further, at the movement direction signal output terminal 13, in equation (3), since a'ω takes a positive or negative value depending on the rotation direction of the encoder 40, the sign detector 12 indicates one direction of movement of the object. It turns out.

As explained above, according to the present invention, the rotational speed when connected to an object to be detected and rotated around the connecting portion is set to have a linear relationship with the change in distance from the center to the peripheral edge. Therefore, not only can the rotational position of the object to be detected be detected immediately, but also detection of minute rotational angles is possible simply by setting a large rate of change in the linear relationship described above, which reduces the processing burden on the encoder itself. Less is. Therefore, highly accurate optical information can be processed with simple processing.

[Brief explanation of drawings]

1A and 1B are diagrams showing an example of the present invention, FIG. 2 is a block diagram showing an example of an optical information processing device, and FIG. 3 is a diagram showing the relationship between an encoder and a slit. , C...axis center, l...reference line, r...distance to peripheral edge, 4...rotary encoder. Agent Anatomist Akiyama High A Figure 1 B 2nd rq ■ ■ Figure 3

Claims (1)

[Claims] A rotary encoder connected to an object to be detected, wherein the rotational speed when rotating around the connecting portion is set in a linear relationship with a change in the distance from the center to the peripheral edge.